Title of Invention	A POLYETHYLENE POLYMER COMPOSITION.
Abstract	Novel polyethylene copolymer composition prepared with homogeneous casaly system are a characterized by hav- ing a unique high molecular weight,low comonomer(high density) fraction.These hetero(xxx) comoposition may may be prepared using asolution polymerization process in which thepolymerization reaction contain a gradient in temperature catalyst conection or monomer connection.The(xxxx)/homogeneous composition of this invention are easily processed into film having excellent (xxx)(xxx)the and low (xxxx).

Title of Invention

A POLYETHYLENE POLYMER COMPOSITION.

Abstract

Novel polyethylene copolymer composition prepared with homogeneous casaly system are a characterized by hav- ing a unique high molecular weight,low comonomer(high density) fraction.These hetero(xxx) comoposition may may be prepared using asolution polymerization process in which thepolymerization reaction contain a gradient in temperature catalyst conection or monomer connection.The(xxxx)/homogeneous composition of this invention are easily processed into film having excellent (xxx)(xxx)the and low (xxxx).

Full Text	This invention relates to polyethylene compositions having a unique balance of properties. Preferred polyethylene compositions may be easily "processed" to produce plastic films having very good tear strength, impact strength and optical properties. BACK GROUND ART Linear low density polyethylene ("LLOPE") copolymers that are prepared by the copolymerization of ethylene with a higher alpha olefin, using 3 conventional Ziegler-Natta type catalyst system are known to contain three different polymer fractions (or "modes"), namely 1) a low molecular weight fraction which contains a high comonomer content: 2) a copolymer fraction of intermediate molecular weight and intermediate comonomer content and 3) a high molecular weight fraction which . contains little or no comonomer. The low molecular weight fraction is sometimes also described as being "highly branched" (due to the high comonomer content) and/or "grease" (due to the low molecular weight). The high molecular weight content is also sometimes described as "homopolymer". The "grease" traction often causes organoleptic problems and may even limit or restrict uses in the which the polymer in contact with food. The "homopotymer" fraction generally imparts a stiffness to the resin and melts at a higher temperature than the other fractions. In general, the non-uniformity of the molecular weight and the comonomer content is a distinguishing characteristic of conventional Ziegler resins. It In contrast, "homogeneous" polyethylene copolymers are generally characterized by having a narrow molecular weight distribution and a narrow composition distribution. The term "homogeneous" was proposed by one of us to describe such polymers in United States Patent (USP) 3.645,992 (Elston), the disclosure of which is incorporated herein by- reference. WO 2004/041927 2 PCT/CA2003/001585 2 As noted in Elston '992, homogeneous polymers have a distinct melting point due to the uniform polymer architecture. The homogeneous polymers disclosed in the Elston '992 patent were prepared with a vanadium catalyst system which is insufficiently active to permit Advances in catalyst technology now permit the production of homogeneous ethylene eopolymers at commercially viable rates. For example, She metallocenelaminoxane catalysts disclosed by Kamlnsky (USP 4,542,199) and improved by Welbom (USP 5,324,800); the ' monocyclopentadienyl catalysts disclosed by Stevens et al. (USP i 5.064,802) and Canich (USP 5,055,438); the ketimine catalysts disclosed by McMeeking et at. (USP 6,114,431); and the phosphinimine catalysts disclosed by Stephan at al (USP 6,063,879) are all highly active for the preparation of homogeneous copolymers. A particularly important end use of LLDPE is the manufacture of films. Films prepared from homogeneous LLDPE generally have good optical properties, good organoleptic properties and excellent impact strength. However, films prepared from homogeneous LLDPE generally have poor tear strength, particularly in the so-called "machine direction". In addition, homogeneous resins are difficult to 'process" (i.e. to convert to films). This poor processability is manifested by high energy demands required to extrude the resin (e.g. large current draws on the electric motors used to drive the extrudes) and/or poor melt strength- Attempts have been made to blend heterogeneous (Ziegler-Natta, or"Z/N") resins with homogeneous resins in order to produce a resin blend which is easier to convert to film and/or to produce film having higher impact strength and good tear properties. USP 5,530,065 (Farley, to Exxon) teaches that a trivial blend of a conventional heterogeneous Z/N resin and a metallocene resin has a balance of properties which are suitable for some film properties. Similarly, USP 5,844,045 and 5,869,575 (Kolthamer, to Dow) also disclose that simple blends of a conventional WO 2004/041927 PCT/CA2003/001585 3 heterogeneous Z/N resin and homogeneous resin prepared with a. monocyclopentadienyl catalyst are also suitable for preparing films. However, it will also be appreciated that the simple blends of the above '065, '045 and '575 patents all contain the low molecular weight "grease" due to the use of the Z/N catalyst to prepare some of the blend composition. Moreover, the disclosures of the "065, 045 and "575 patents are silent with respect to the hexane extractables contents of the blends. Thus, films prepared from conventional heterogeneous resins have comparatively poor Impact strength, optical properties and organoleptic properties — but do have very good tear strength. Conversely, films prepared from homogeneous resins have excellent impact strength, optical properties and organoleptic properties-- but poor tear strength. Previous attempts to utilize resin blends to eliminate this problem have not been completely successful. Simple blends of heterogeneous resins with homogeneous resins provide films with sub-optimal orcrsnoleptic properties (presumably because of the "grease" fraction or made in the conventional heterogeneous resin). Another attempt to solve This problem Is by preparing blends of more than one homogeneous resin is disclosed in USP 5.382,630. and 5,382,631 (Stehling etal, to EXXON). Stehling al. '631 teach blends which are characterized by the substantial absence of blend components having a higher molecular weight and a lower comonomer content than other blend components (e.g. the high molecular weight homopolymer of conventional heterogeneous resins. These blends are shown to be useful -for the preparation of structures having improved tear properties, However, the disclosure of this patent is silent on the subject of impact suffer a very large loss of dart impact strength where the amount of lower molecular weight higher density component is sufficient to enhance tear strength .One of us disclosed a dual reactor solution polymerization process to prepare a homogeneous copolymer composition which is useful for the preparation of films (Brown, USP 6,372,864). None of the inventive WO 2004/041927 PCT/CA2003/001585 4 copolymer compositions disclosed in Brown S64 contained the high molecular weight, high density (very low comonomer) fraction which is an Thus, Films prepared from conventional heterogeneous resins have comparatively poor impact strength, optical properties and organoleptic I properties - but do have very good tear strength. Conversely, films prepared from homogeneous resins have excellent impact strength, optical properties and organoleptic properties - but poor tear strength. Previous attempts to utilize resin blends to eliminate this problem have not been completely successful- Simple blends of heterogeneous resins with homogeneous resins provide films with sub-optimal organoleptic properties and optical properties (presumably because of the "grease" fraction or made In the conventional heterogeneous resin), DISCLOSURE OF INVENTION We have now discovered a heterogenized/homogeneous polymer composition which may be used to prepare films having an improved balance of impact strength, tear strength and organoleptic propertis. In addition the heterogenized/homogeneous polymer compositions of this invention are surprisingly easy to "process" in machinery used to \| convert the compositions into films (in comparison to homogeneous resins. The heterogenized/homogeneous polymer compositions must be prepared using a "homogeneous catalyst" - i.e. a catalyst system that will produce homogeneous polymers (having a narrow molecular weight distribution and a narrow composition distribution) In a conventional polymerization reactor. In addition, the hetorogenized/homogeneous polymer compositions of this invention must contain at least one first copolymer fraction and a second high molecular weight/high density fraction. This second fraction is somewhat analogous to the "homopolymer" fraction of heterogeneous resins, In this sense, the compositions may be referred to as being "heterogenized". Thus, the polymer compositions of this Invention are made with "homogenous" WO 2004/041927 PCT/CA2003/001585 5 components prepared with a "homogeneous" catalyst system but they must also contain a high molecular weight, high density component which is analogous to a "heterogeneous" resin. Thus, in one embodiment, the present invention provides a heterogenized/homogeneous polymer composition prepared with a homogeneous catalyst system, said composition comprising: A) a first polymer fraction having a density of from 0.880 to 0.945 grams per cubic centimeter as measured by ASTM D792: a melt index, (2, of from 0.1 to 200 grams per 10 minutes as determined by ASTM D1238,- less then 2 weight % hexane extractables: and a substantial absence of homopolyrner wherein said first polymer fraction comprises at least one homogeneous copolymer of ethylene and at least one C4to 10 alpha olefin, and wherein each of said at least one homogeneous copolymer is characterized by having a molecular weight distribution. Mw/Mn, of less then three; and B) a second polymer fraction having a higher molecular weight then said first fraction; a higher density then said first fraction; and a lower alpha olefin content then said first fraction, wherein said second polymer fraction comprises at least one second homogeneous polymer of ethylene. optionally with at least one C4to10 alpha olefin comonomer, and wherein each of said at least one second homogoneous polymer of elthylene is characterized by having a molecular weight distribution, Mw/Mn, of less then 3. As noted above, the second traction must have both of a higher molecular weight and a lower comonomer content than the first fraction. It will be appreciated by those skilled in the art that it is extremely difficult to prepare such a polyrner composition by a simple mechanical blend of the two polymer fractions. Accordingly, if is highly preferred to prepare the present compositions by solution blending - especially via a solution polymerization process in which the fractions are blended in situ. It is particularly preferred to use two continuously stirred tank reactors (CSTRs) to prepare the compositions - although a single tube reactor WO 2004/041927 PCT/CA2003/001585 6 (plug. flow reactor) or a combination of a tube reactor and a CSTR may also be suitably employed. The compositions of this invention may be used to prepare a wide variety of goods including injection molded parts, rotomolded parts and film. Preferred compositions which are described in more detail below are especially suitable for the preparation of films. The film may be prepared by conventional "cast" or "blown bubble" techniques. Monolayer films or multilayer films (prepared by coextruslon of multiple layers of laminates) are possible. The resulting films may be used to package foods and I consumer goods in sealed packages, including sealed packages for Iiquid. The films are also suitable for preparing trash bags, "heavy duly packages" (for such goods as peat moss-and other gardening items including bark, fertilizer and decorative gravel - that are exposed to the outdoors in gardening centers); shrink films (which may be used in high performance packaging for poultry or cuts of meat); pallet wraps (to protect goods on pallets during shipping and/or outdoor storage); and stretch films. The plastic parts and films prepared from the polymer compositions of this invention may include conventional additives such as antioxidants (e.g. hindered phenols and phosphates); UV stabilizers such as hindered amines; antiblocks (e.g. talc and silica); antistatic agents (e.g. low molecular weight polyethylene glycol); processing aids (e.g. fluoropolymers and polyethylene glycols having a molecular weight of from 2.000 to 8,000); pigments and the like. BEST MODE FOR CARRYING OUT THE INVENTION Part1. (Description of Catalysts In general, any catalyst system which produces a "homogeneous" (as defined by Elston '922) ethylene capolymer may be used to prepare the composition of this invention. It is preferred to use a catalyst of a group 4 metal which provides an activity of at least 250,000 grams of polymer per gram of group 4 metal. Preferred catalysts contain at least one cyclopentadienyl ligand. Examples of such catalysts are disclosed in+ WO 2004/041927 PCT/CA2003/001585 7 the aforesaid Welbom '800. Stevens '802. Stephan '879 and McMeaking '481 patents. A preferred catalyst used In the process of this invention is an organometallic complex of a group 3,4 or 5 metal which is characterized by having a cyclopentadienyl ligand (as defined in section 1.3 below) and a phosphinimine ligand(as defined in section1.2.1below)or a kitimide ligand (as defined in section 1.2.2 below], Any such organometallic having a phosphinimine ligand which displays catalytic activity for ethylene polymerization may be employed. Preferred catalysts are defined by the formula: wherein M is a transition metal selected from 71, Hf and Zr (as described in section 1.1 below); Cp Is a cyclopentadienyl ligand (as broadly defined in section 1.3below);i.is a phosphimine ligand or a ketimide X is an activatable ligand which is most preferably a simple monoanionic ligand such as alkyl or a halide (as described in section 1.4 below); and p is one or two depending upon the valence of M and X. The most preferred catalysts are group 4 metal complexes in the highest oxidation slate. For example, a preferred catalyst may be a I cyclopentadienyl (phosphinimine) dichloride complex of titanium, zirconlum or hafnium. It is especially preferred that the catalyst contain one phosphinimine ligand, one cyclopentadienyl ligand, and two "X" ligands (which are preferably both chloride), 1.1 Metals I The preferred catalyst is an organomelallic complex of a group 3.4 or 5 metal (where the numbers refer to columns in the Periodic Table of the Elements using lUPAC nomenclature). The preferred metals are from group 4, (e.g. titanium, hafnium or zirconium) with titanium being most Preferred. WO 2004/041927 PCT/CA2003/001585 8 ' 1.2.1 PhosphInlmine Ligand A preferred catatysl contains a phosphinimlne ligand which is covslently bonded to the metal. This ligand is defined by the formula: wherein each R1 is independently selected from the group consisting of a hydrogen atom, a halogen atom, C1-20 hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, a C1-8 alkoxy radical, a C6 10 aryl aryloxy radical, an amido radical, a silyl radical of the formula: Si-(R2)3 wherein each R2 is independently selected from the group consisting of hydrogen, a C1-8 or alkoxy radical, C6-10 or aryloxy radicals, and , a germanyl radical of the formula; Ge-(R2)3 wherein R2 is as defined above. The preferred phosphinimlnes are those in which each R1 is a hydrocarbyl radical. A particularly preferred phosphinimine is tri-(tertiary butyl) phosphinimine (i.e. where each R1 is a tertiary butyl group). 1.2.2 Ketirmide Ligads As used herein, the term "ketimide ligand" refers to a ligand which; (a) is bonded to the transmission metal via a metal-nitroge atom bond;(b) has a single substituent on the nitrogen atom, (where this single Substituent is a carbon atom which is doubly bonded to the N atom); and (c) has two substituents (Sub 1 and Sub 2. described below) which are ' bonded to the carbon atom. Conditions a,b and c are illustrated below. WO 2004/041927 PCT/CA2003/001585 9 The substituents "Sub 1 and Sub 2" may be the same or different. Exemplary substituents include hydrocarbyls having from 1 to 20 carbon atoms; sllyl groups, amido groups and phosphido groups. For reasons of cost and convenience it is preferred that these substituents both be hydrocarbyls, especially simple alkyls and most preferably lertiary butyl. 1.3 Cycfopentadienvl Ligands i Preferred catalysts are group 4 organometallic complexes which contain one phosphinimine ligand or ketimide ligand and one cyclopentadienyl ligand. As used herein, the term cyclopentadienyl ligand is meant to convey its broad meaning, namely a ligand having a five carbon ring which is bonded to the metal via eta-5 bonding. Thus, the term "cyclopentadienyl" includes unsubstituted cyclopentadienyl, substituted cyclopentadienyl. unsubstituted Indenyl, substituted indenyt, unsubstituted fluorenyl and substituted fluorenyl. An exemplary list of substituents for a cyclopentadlenyl ligand includes the group consisting of C1-10 hydrocarbyl radical (which hydrocarbyl substituents are unsubstituted or further substituted); a halogen atom, C1-8 alkoxy radical, a C6-10aryl or aryioxy radical; an amido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals; a phosphido radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals; silyl radicals of the formula —Si- (R)3 wherein each R is independently selected from the group consisting of hydrogen, a C1-8 alkyl or alkoxy radical C6-10 arly or aryloxy radicals; germanyl radicals of the fomula Ge—(R)3 wherein R is as defined directly above. WO 2004/041927 PCT/CA2003/001585 10 1.4 Activatable Ligand X The term "activatable llgand" refers to a llgand which may be activated by a cocafalyst (also referred to as an "activator"). to facilitate olefin polymerization. Exemplary activatable ligands are independently selected from the group consisting of a hydrogen atom, a halogen atom, a C1-10 hydrocarbyl radical, a C1-10 alkoxy radical, a C5-10 aryl oxide radical: each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be unsubstituted by or further substituted by a halogen atom, a C1-8 alkyl radical, a C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amldo radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals; a phosphldo radical which is unsubstituted or substituted by up to two C1-8 alkyl radicals. The number of activatable llgands depends upon the valency of the metal and the valency of the activatable ligand. For example, a single divalent activatable ligand (such as butadiene) may be used with a group 4 metal in the 4* oxidation slate. The preferred catalyst metals are group 4 metals in their highest oxidation slate (i.e. 4') and the preferred activatable ligands are monoanionic (such as a halide - especially chloride or a alkyl - especially methyl). Thus, the preferred catalyst contain a phosphinimlne ligand, a cyclopentadienyl ligand and two chloride (or methyl) ligands bonded to the group 4 metal. In some instances, the metal of the catalyst component may not be in the highest oxidation state. For example, a I titanium (111) component would contain only one activable ligand. \| 1.5 Summary Description of Preferred Catalyst As previously noted, The most preferred catalyst is a group 4 organometallic comptex in its highest oxidation state having a phosphinimine ligand, a cyclopentadienyl-type ligand and two activatable ligands. These requirements may be concisely described using the following formula for the preferred catalyst: -WO 2004/041927 PCT/CA2003/001585 11 wherein (a) M is a metal selected from Tl Hf and Zr, (b) Pl is a phosphinimine ligand defined by the formula; wherein each R is independently selected from the group consisting of .$ hydrogen atom, a halogen atom, C1-20hydrocarbyl radicals which are unsubstituted by or further substituted by a halogen atom, a C1-8 alkoxy radical, a C6-8 ARLY or aryloxy radical, an amido radical, a silyl radical of the formula: S-(R2)3 wherein each R2 is Independently selected from the group consisting of hydrogen, a C1-8 alkyl or alkoxy radical, C6-10 aryl or aryloxy radicals, and,a germanyl radical of the formula: Ge-(R2)3 wherein R2 is as defined above: (c) Cp is a ligand selected from the group. consisting of cyclopentadienyl. substituted cydopentadienyl, indenyl, substituted indenyl, fluorenyl. substituted fluorenyl; and (d) each X is an activatable ligand. 2. Description of Cocatalyst The catalyst components described in part 1 above are used in combination with at least one cocatalyst (or "activator") to form an active catalyst system for oletin polymerization. Preferred activators are decribed in more deatail in section 2.1and 2.2 below. 2.1 Alumoxane The alumoxane may be of the formula: (R4)2AIO(R4AIO)mAl(R4)2 wherein each R4 is independently selected from the group consisting of C1-20 hydrocarbyl radicals and m is from 0 to 50, preferably R4 is a C1-8 -WO 2004/041927 PCT/CA2003/001585 12 alkyl radical and m is from 5 to 30. Mathylalumoxane (or "MAO") in which each R is methyl is the preferred alumoxana. Alumoxanes ara well known as cocatalysts, particularly for metallocene-type catalysts. Alumoxanes are also readily available articles The use or an alumonxane cocatalyst generally requites a molar ratio of aluminum to the transition metal in the catalyst from 20:1 lo 1000:1. Preferred ratios are from 50:1 to 250:1. Commercially available MAO typically contains free aluminum alkyl (e.g. trimethylaluminum or "TMA") which may reduce catalyst activity and/or broaden the molecular weight distribution of the polymer. If a narrow molecular weight distribution polymer is required, jt is preferred to treat such commercially available MAO with an additive which is capable of reading with the TMA. Alcohols are preferred (with hindered phenols being particularly preferred) for this purpose. I 2.2 "Ionic Activators' Cocatalysts ' So-called 'ionic activators" are also well known for metallocene catalysts. See, for example. USP 5.198,401 (Hlathcy and Tumer) and USP 5.132,380 (Stevens and Neilhamer). Whilst not wishing to be bound by any theory, it is thought by those skilled in the art that "ionic activators" initially cause the abstraction of one or more of the activatable ligands In a manner which ionizes the catalyst into a cation, then provides a bulky, labile, non-coordinating anion which stabilizes the catalyst in a cationic form. The bulky, non-coordinating anion permits olefin polymerization to proceed at the cationic catalyst center (presumably because the non-coordinating anioin is sufficiently labile to be displaced by monomer which coordinates to the catalyst. (i) - (iii) below. (i) compounds of the formula [R5]'B(R7)4]'wherein B is a boron atom, R5- is a aromatic hydrocarbyl (e.g. triphenyl methyl cation) and each R7 is independently selected from the group consisting of phenyl' WO 2004/041927 PCT/CA2003/001585 13 radicals which are unsubstituted or substituted with from 3 to 5 substituents selected from the group consisting of a fluorine atom, a C1-4 alkyl or alkoxy radical which is unsubstituted or ubstituied by a fluorine atom; and a silyl radical of the formula S-(R9)3; wherein each R9 is independently selected from the group consisting of a hydrogen atom and a C1-4 alkyl radical; and (ii) compounds at the Fomula [(R8) ZH][B(R7)4] wherein B is a boron atom, H is 3 hydrogen atom,Z is a nitrogen atom or phosphorus atom, t Is a or 3 and R8 is selected from the group consisting of C1-8 alkyl radicals, a phenyl radical which is unsubstituted or substituted by up to three C1-4 alkyl radicals, or one R8 taken together with the nitrogen atom may form an anillnium radical and R7 is as defined above; and (iii) compounds of the formula B(R7)3 wherein R7 is as detined above. In the above compound preferably R7 is a pentafluorophenly radical, and R5 is a Iriphenylmethyl cation, Z is a nitrogen atom and R8 is a C1-4 alkyl radical or R8 taken together with the nitrogen atom forms an anilinium radical which is substituted by two C1-4 alkyl radicals. The"ionic activator "may abstract one or more activatabte ligands so as to ionizing catalyst center into a cation but not to covalenlly bond with the catalyst to provide sufficient distance between the catalyst and the ionizig active to permit a polymerizable olefin to enter the resuliting active site. Example of ionic activators include triothylamonium tetra (phenyl)boron. triprophylamnium tetra(pheny))boron, (n-buthyl)ammonium tetra(phenyl)borun, trimethlammonium tetra(p-tolyl)boron, trimethylammonium tetra(O-tolyl)boron, trimethylammonium tetra(pentafluorohenyl)boron. trimethylammonium tetra(o.p-dimethylphenyl)boron, trimethylammonium tetra(m.m-di methyl phenyl ]boron, WO 2004/041927 PCT/CA2003/001585 14 tributhylammonium tetra(p-triuoromethyphenyl)boron tributylammonium tetra(pentafluorophenly) boron tri(n-butyl)ammonium tetra (o-tolyl) boron N,N-diethylanllinium tetra(phenyl)boron, N,N-diethylanllinium tetra(phenyl)boron, N,N-diethylanllinium tetra(phenyl)boron, N,N-2,4,6 pentamethylanilinium tetra(phenyl)boron, di-(isoproprophyl)ammonium tetra(pentraflourophenthore, dicyclohexlammonium tetra(phenyl)boron tri(methylphenyl)phosphonium tetra(phenyl)boron tri(methylphenyl)phosphonium tetra(phenyl)boron tri(methylphenyl)phosphonium tetra(phenyl)boron tropillium tetrakispenta fluorophenyl borate, triphenylmethyllium phenyttrispentalfluorophenyly borate, benzene(diazonlum) tetrakispenta fluorophenyl borate tropllium phenyltriphenyt trispentalfluorophenly borate tropillium tetrakls (2,3,5,6-terafluorophenyl) borate, benzene(diazonlum) tetrakispenta (3,5,6-terafluorophenyl) borate, tropillium tetrakis(,3,4,5trispentalfluorophenly )borate benzene(diazonlum) tetrakis (3,4,5 fluorophenyl) borate tropillum tetrakis (1,2,,2trispentalfluorophenly)borate tributhylammonium tetrakis (1,2,2trispentalfluorophenly)borate benzene(diazonlum) tetrakispenta (1,2,2-tetrafluorophenyl) borate tropillium tetrakis(2,3,4,5trispentalfluorophenly )borate triphenylmethylium tertrakis (2,3,4,5 tetrafluorophenyl) borate benzene(diazonlum) tetrakis (,2,3,4,5-tetrafluorophenyl) borate Readily commercialy available ionic activators includes N N-diamethylaluminutetetrakispentaflurophenyl borate. triphenylmethylium tetrakispentafluophenyl borate and -WO 2004/041927 PCT/CA2003/001585 15 trispenfafluorophenyl borane. 3. Description of Dual Reactor Solution Polymerization Process Solution processes for the (colpolymarization of ethylene are well knowin that art.These processes are conduted in the presence of an inert hydrocarbon sovent(typicaliy a C5-12 hydrocarbon which, which be unsiib5tr(uied or substituted by a CM affcyf group, such as pentane, methyl perrtane. fiexane, heptane, octane, cycfofiexane. mefliycyctafiexane and hyrirogenated naphtha. An example of a suitable solvent which is commercially available is "(sopar p (CIM? aliphatic solvent, Exxon Chemical Co.). The preferred solution polymerisation process for this invention uses at least two pdymsrisJEion rssctors- The pc!yTrreri2a8an tempef^ftire i^i [Ire rrrsf rvzetof Is Itatn abof/f SO°C to about iflO°C (pnsferaWv from about !EO"C to ISO'CJ ancf ifve second reactor Is preferably operated at a higher terrro^rafure (4/p fo sfcaut 220°C). The most prefened rescfon process is a "medium pressure pmcess', rrwaning that trie pressure in eacft reactof is prefersWy less ^arr about 6,000 psi (about A 2,000 kitoPzscais or kPa), most preferably from si?out 2,000 psi to 3,000 psi (about 14.000-22.000 JfPa). SuSaWe monomers for copolymerization with ethylene include XXX ajpha olefins. Pi&f&ired comonomeis 'mciuOs alpha o}&liri$ which sas uxissjbstituled Of substituted i?y yp io hw^ C?.§ sJJcyi fadir^Js. WJusfis^ve non-Jimilin0 exampJes Of such ^^ph^-c^lefi^s are one or more of propyfe^e, 1-buteoe. 1-peuIene, 1-hexene, 3-octerjeand 1-derene. The heterogeneous/homogeneous copolymer compositions which may be prepared in accordance with the present invention are preferably U-DPE'S which typically comprise not less than 60, preferably not less than 75 weight % of ethylena and the balance one or more C-«, alpha oleiins, preferably selected from the group consisting of 1-butene. 1- hexane and 1-octene. The polyethylene prepared in accordance with the present invention may be LLDPE having a density from about 0.910 to 0.93G glee or [linear) high density polyethylene having a density above WO 2004/041927 PCT/CA2003/001585 16 0.935 glce. The present invention might also be useful to prepare polyethylene having a density below 0,910 g/cc - the so-called very low and ultra low density polyetiiylenes. Generally (he alpfra olefin may be present in an amount from about 3 to 30 weight %. preferably from about 4 to 25 weight %. The monomers are dissolved/dispersed in the solvent either prior to being fed to the first reactor (or for gaseous monomers the monomer may- be fed to the reactor SD that it will dissolve in the reaction mixture). Prior to mixing, the solvent and monomers are generally purified to remove potential catalyst poisons such as water, oxygen or metal impurities. The feedstock purification follows standard practices in the art, e.g. molecular sieves, alumina beds and oxygen removal catalysts are used for the purification of monomers. The solvent itself as well (e.g. methyl pentahe, cyctohexsne, hexann or toluene) is preferably treated in a similar manner. Tha feedstock may be heated or cooled prior to feeding to the first reactor. Additional rnonomers and solvent may be added to the second reactor, and it may be heated or cooled. Generally, the catalyst components may be premised in the solvent for the reaction orfed as separat stream to each reactor.In some Instances premixing it may be desirable to provide a reaction time for the catalyst components prior to entering the reaction. Such an in line mixing" technique is described in a number of patents in the name of DuPont Canada Inc (e.g. USP 5.589,555, issued December 31,1996). The residence time in each reactor will depend on the design and the capacity of the reactor. Generally the reactors should be operated under conditions to achieve good mixing of the reactants. In addition, it is preferred that from 20 to 60 weight % of the final polymer is polymerized In the first reaclor, with the balance being polymerized in the second reactor. On leaving the reactor system the solvent is removed and the resulting polymer is finished in a conventional manner. In a highly preferred embodiment, the first polymerization reactor has a smaller volume than the second polymerization reactor. In addition WO 2004/041927 PCT/CA2003/001585 17 the first polymerization reactor is preferably operated at a colder temperature than the second reactor. Preferred Polymer Compositions Polyethylene resins are often converted to finished products by a melt extrusion process. Extrusion processes generally produce more "drawdown" of the polyethylene melt in the machine direction (MD) than the transverse direction (TD) due to the force which is required to "draw the melt through the extrusion die. This typically produces a finished plastic part with unbalanced mechanical properties which vary with the orientation or direction of measurement A common example of this phenomenon is illustrated by considering an injection molded plastic cup. These cups are usually fabricated by forcing the plastic melt through an Injection port at the base of the cup mold thus producing a flow from the base of the cup to the lip of the cup in a lengthwise direction. The finished plastic cup therefore has a "machine direction" along the length of the cup and is more prone to split or tear in this lengthwise direction (i.e. the cup is less prone to fail around the circumference or "transverse direction"). An analogous phenomenon is observed with polyethylene films. That is, extiuded plastic films generally have poor "machine direction" tear strength in comparison to transverse directionh tear slrength.This may be referred to as a tear strength imbalance. It has been observed that this effect (i.e. MD vs. TD tear Imbalance) becomes more pronounced in films prepared from heterogeneous ethylene-butene copolymers as the molecular weight of the copolymer increases. That is, the relative MD vs. TD imbalance becomes more pronounced in films prepared from higher molecular weight heterogeneous copolymers. While not wishing to be bound by theory, it is postulated that this phenomenon is a result of the greater stress which is required to extrude the higher molecular weight copolymer (which in turn gives rise to a higher orientation of the polymer molecules and thereby causes a higher MD/TD imbalance). This phenomenon has also been observed to become even more pronounced with homogeneous resins. While again not wishing to be WO 2004/041927 PCT/CA2003/001585 18 bound by theory, it is believed that the uniform structure of a homogeneous resin causes the polymer molecules to be very uniformly oriented during melt extrusion. In any event, the MD tear of films prepared from homogeneous polymers is generally very poor. However, the impact strength of films prepared from homogeneous polymers is usually excellent. As previously noted, It is Known to prepare homogeneous ethylene polymer compositions in which a fraction or blend component of the \| composition contains a higher density but lower molecular weight then the other polymer fraction (e.g. me Stehting et al. '631 patent and the commercially available EXCEED™ 1016 resin). In contrast, the compositions of this invention must contain a second" polymer fraction which is both higher molecular weight and higher density (or alternatively stated, "less branched') than the first copolymer fraction. It is preferred that this high molecular weight/high density fraction be present in an amount of from 1 to 20 weight %, especially from 2 to 10 weight %, of the total polymer composition. It is also preferred that the high molecular weight/high density fraction has less than 5, especially less than 4, short branches per 1,000 carbon atoms. It is further preferred that the high molecular weight/high density fraction has a weight average molecular weight, Mw.of from 130.000 to 500,000, especially more than 150,000 to 500.000. The "first" fraction of the polymer compositions of this invention contains at least one homogeneous copolymer. The first fraction may contain more than one homogenous copolymer but this is not necessary. The heterogenrzed/homogenous compositions of this invention are especially suitable for the preparation or films. It is preferred that films prepared from a heterogenized/homegenous composition have an overall density or from 0.900 to 0.940 g/cc (especially from 0.90B to 0.920) and ar\| overall melt index. I2 of from 0.3 to 20. WO 2004/041927 PCT/CA2003/001585+ 19 EXAMPLES I Part 1. Comparative Examples A sample of commercially available resin sold under the trademark EXCEED™ f 1019CA by ExxonMobil Chemical was subjected to a gel permeation chromatography (GPC) analysis to determine molecular weight distribution and a temperature rising elation fractionation (TREF)1 analysis. Trichlorobenzene was used as the mobile liquid phase for the TREF analysis. The GPC analysis is described in Part 2 below. The EXCEED™ 1018CA resin is reported to be an ethylene-hexene copolymer produced using ExxonMobil Chemicals' EXXPOL™ technology (which is believed to be a metallocena catalyst technology). The TREF analysis of this resin showed two distinct elution peaks- The first peak - indicative of a homogeneous copolymer fraction —was observed at 80.7ºC. A second fraction having less comonomsr (high density fraction) was observed to elute at 93.1°C. GPC analysis of the whole resin showed the weight average molecular weight (Mw) to be about 101,000 and the molecular weigh! distribution to be about 2.1. according to elution temperature (using a conventional TREF preparation technique with trichlorobenzene as the moblie liquid phase solvent). The high density fraction (or cut), which eluted at a temperature of from so to 95°C, was observed to be about 8.5 weight % of the total polymer \| composition. This fraction was analyzed to have a weight average I molecular weight of 72,000. Thus, this sample of EXCEED™ 1018CA is consistent with the disclosure of ths aforesaid Stehling et al. '630 patent because the 'high density" fraction has a toner molecular weight than the conolymer fraction (i.e. 72,000 vs. 101,000). One mil films prepared from EXCEED™ 1O1BCA (on a blown film line having a 60 mil die gap, using a 2.5:1 blow up ratio) are reported by ExxonMobil Chemical to have (typical) WO 2004/041927 PCT/CA2003/001585 20 dart impact strength of 740 grams, machine direction (MD) tear strength of 260 gratis, and transverse direction (TD) tear strength of 340 grams. Comparative Example An ethylene-octene copolymer having a density of 0.917 grams per cubic centimeter (g/cc) and a molecular weight distribution (Mw/Mn) of 18- was prepared in a solution polymerization process using a titanium catalyst having one cyclopentadienyl ligand, one tri(terllary butyl) phosphinimine ligand and two chloride ligands (referred to hereinafter as. CpTiNP(t-Bu)3Cl2) and an activator consisting of a commercially \| available methyl aluminoxane ("MAO") at an A/Ti mole ratio of 100/1 and' triphenyimethylium tetra kispentafluorophenyl borate ("Ph3CB(C6F5)4") at a Bm mole ratio of 1.2/1. The resulting copolymer did not contain a very high density/higher melting point fraction In any meaningful amount. , A blown film having an average thickness of 1 mil was prepared using a conventional extruder al a blow up ratio of 2.5/1 through a 3.5 mil die gap. The resulting film had a dart impact of greater than 1,000 grams, a machine direction tear strength of 250 grams and a transverse direction tear strength of 340 grams. Part2 Inventive Polymerizations The examples illustrate the continuous solution copolymerization of ethylene and octene at medium pressure. The Inventive examples used a first continuously stirred tank reactor ("CSTR") which operated at a relatively low temperature (see Table B.1). The first reactor pressure was about 14.5 Mega Pascals, and the second reactor pressure was marginally lower (to facilitate flow from the first to second reactor). The contents from this reactor flowed into a larger, second polymerization reactor which was also a CSTR. The volume of reactor 2 was 1.8 times larger than the volume of reactor 1. The process was continuous In all "feed streams (i.e. solvent, which was methyl pentane; monomers and catalyst systems) and in the removal WO 2004/041927 PCT/CA2003/001585 21 of product monomer were purified prior to addition to the reactor using conventional feed preparation systems (such as contact with various absorption media to remove impurities such as water, oxygen and polar contaminates). Feeds (monomers, catalysts, activators) were pumped to the reactors as shown in Table B.1. Average residence times for the reactors were calculated by dividing average flow rates by reactor volume. The I residence time in each reactor for all of the inventive experiments was less than 1.5 minutes and the reactors were well mixed. While not wishing to be bound by theory, it is believed that the short residence time of the inventive polymerization reads to small temperature. catalyst and/or monomer concentration gradients which cause the formation of the high molecular weight/high density polymer component which is essential to the compositions of this invention. The catalyst used in all experiments was a titanium (IV) complex I having one cyclopentadienyl ligand, two chloride ligands and one tri \| (tertiary butyl) phosphinimine ligand (-CpTiNP(Bu)3Cl2"). The cocatalysls were a commercially available methylalumoxane ("MAO") and a commercially available borate ('Ph3CB(C6F5)4-). A hindered phenol (2,6 di-tertiary butyl, 4-ethyl, phenol) was also used as shown in Table B.1. The amount of catalyst added to each reactor(expressed as parts per million (ppm) by weight, based on the total mass of the reactor contents) as shown in Table B1. The MAO. borate and phenol were added in the amounts shown in Table B.I. The amount of MAO (expressed as moles of Al per mole of Ti (in the catalyst)), berate (expressed as moles of 8 per mol of Ti) and moles of phenol (expressed as moles of OH per mole of Al in the MAO) is shown in Table 8.1 where "R1" refers to reactor 1 and "R2" refers to reactor 2. The ethylene concentration in reactor 1 ( R1") is expressed as weight %. An equivalent flow of ethylene was provided to each reactor. The total amount of octene used in both reactors is reported in ■ TableB.1 based on the total amount of ethylene (mole/mole basis). The WO 2004/041927 PCT/CA2003/001585 22 fraction of the oclene added to R1 is shown in Table B.1 (with the remaining octene being added to the second reactor R2"), I Hydrogen was added to the reactors in small amounts as shown in Table B.1 (expressed as ppm by weight). (For clarification: Table B.1 shows that the first composition, was prepared using the following average conditions in reactor 1 (R1"); I catalyst concentration of 0.099 ppm;boron/Ti=1.1 (mol/mol): AUi-65A (mol/mol); OHAI=0.3 (mol/mol); ethylene concentration=9.2 weight %: 80% of the total octene added toR1 and R2 was added to R1; the total oetenefethylene mole ratio was D.B5; the hydrogen concentration was 0.23 ppm by weight in R1; the mean R1 reactor temperature was 139.8°C and the residence time was 1.0 minutes). The composition of the monomer feeds and the position of the monomer feed port(s) relative to the catalyst feed port in the second reactor R2 was varied to examine the effect of these variables upon the microstructure of the heterogenized homogeneous compositions of this invention. The feed ports to reactor 1 were not adjusted for any of the experiment .One feed port was used to add ethylene and octene In solvent and another feed port was used for all of the catalyst components added to R1. The entry port into reactor R2 for the polymer solution from R1 was not changed for any of the experiments shown inTable B.1 — it was located on one side of the reactor about midpoint between the top and bottom. The first product (entry 1 in Table B.1) was prepared by feeding the fresh monomer and catalyst at the bottom of the reactor R2 through separate feed lines. Product 2 was prepared by moving the fresh monomer feed to the side of reactor. Product 3 to 6 were prepared using "split fresh monomer feed"i:e. through two nozztes on theside of the reactor. Cocatalyst flows and WO 2004/041927 PCT/CA2003/001585 23 hydrogen flows were also changed for Products 3 to 6 as shown in Table B.1. Polymer properties were measured using test methods described below Melt index ("Ml") measurements are conducted according to ASTM method D-1238. Polymer densities are measured using ASTM 0-1928. Molecular weights were analysed by gel permeation chromatography (GPC), using an Instrument sold under the tradename 'Waters 150c",with 1,2.4-trichlorobenzene as the mobile phase at 140°C. The samples were prepared by dissolving the polymer in this solvent and were run without filtration. Molecular weights are expressed as polyethylene equivalents with a relative standard deviation of 2.9% for the number average molecular weight ("Mo") and 5.0% for the weight average molecular weight ("Mw"). Film properties were measured using the following test methods' Haze (ASTM D-1003); Gloss (ASTM D-2457); MD Tear and TD Tear Resistance (ASTM D-1922); ' Dart Impact Strength (ASTM D-1709); and ' Hexane Extraetables (Complies with U.S. Food and Drug Administration (FDA) test set out in the Code of Federal Regulations Title 21. Parts 177.1520. In general, a film sample is extracted in hexane at 50°C for2 hours.) Melt index, l2, and density data for each of the heterogenized homogeneous compositions are also given in Table B.1, TREF and GPC analysis of Products 1,4 and 6 was then completed. Product 1 was expected to be most "heterogenized" (due to the previously discussed locations of the fresh monomer feed and catalyst ports). Product 1 had an Mw of 93,300; an Mn of 24,000; and an average of 15 short chain branches per 1,000 carbon atoms. 91.5 weight % of the composition eluted at the lower temperatures expected for homogeneous copolymers. However, 8.5 weight % of Product 1 eluted over a higher) WO 2004/041927 PCT/CA2003/001585 24 temperature range of from 88 to 110°C. This fraction had an Mw of 130,400 and only 3.9 branches per 1,000 carbon atoms -thus, it was higher molecular weight and lower comanomer content (higher density) than the remainder of the composition. These data are shown in Table B.2, together with analogous date for Product 4 and 6 (from the polymerization examples). In Table B.2, *SCB refers to the number of short chain branches per 1000 carbon atoms. A low SCB figure indicates a low amount of comonomer. The term "heterogenized fraction" in Table B.2 refers to the high molecular weight, high density component which elutes at a temperature of the total heterogeneous/homogeneous composition. For clarity, the data in Table B.2 show that Product 1 contained 8.5 weight % of the high density/high molecular weight, low comonomer content material and Product 6 contained 5.9 weight %. ' Part 3. Film Preparation Films were prepared from compositions 1 to 6 which ware prepared in the polymerizations observed above. A comparative film was also made using the previously described commercially available EXCEED™ 1018 I product The films were manufactured on a conventional blown film line which was fed by a single screw extruder having a 3.5 inch screw diameter. The extruder was driven by an electrical motor. Conventional additives (antioxldants and process aid) were added to all extrusions. The extrudate was forced through a circular die having a four inch diameter and a 35 mil die gap. A blow up ratio (BUR) of 25:1 was used to prepaid the film. Other processing conditions (output, head pressure and motor \| toad) are shown in Table C.1. Referring to Table C1.it can be seen that I the electrical power demand required to drive the extruder is expressed as a current load on the motor (expressed in amps) to produce a given film output (expressed in pounds of film per hour). The electrical demand for the product from experiment 1-C was 54 amps for a 100 Ibs/hr throughput (in comparison to 36-39amps for the inventive composition). Thus, the WO 2004/041927 PCT/CA2003/001585 25 comparative LLDPE of experiment 1-C has poor "processability" (as indicated by load or the electrical motor). Physical properties of the films are shown inTableC.1!. The "hexane extractables" content of all films is very low. This is a very desirable feature of films mads from a homogeneous catalyst system. The comparative film 1-C had a very high dart impact strength but tear properties. [Note that the "dart" impact strength of 1,226 g is significantly higher than the typical" value of 740 reported by the resin manufacturer — as discussed in Part 1 above. However, the MD and TD tear strength numbers shown in Table C.1 (255 g and 337 g) correspond very closeiy to the -typical- values (MD=260 g, TD=340 g) reported by the manufacturer of the EXCEED™ 1018 resin.] All of the inventive compositions 2 to 6 have significantly improved tear strengths. Moreover, the films made from heterogeneous/homogeneous- resins 4 to 6 also exhibit very good impact strength, \| It will also be noted that the "haze" values of all of the films I prepared on this machine were not very impressive. Additional experimentation showed that the haze values could be greatly improved by blending some high pressure low density ("LD") resin or conventional (heterogeneous) linear low density resin with the inventive resins. Blends of up to 40 weight % of the LD or heterogeneous LLDPE resins may be used to improve haze results and amounts as low as 0.25 to 3.00 weight For example, three blends of a high pressure, low density polyethylene "LD" (having a density of 0.921 g/cc and a melt index,\|l2, of; The three blends contained 2 weight %, 3 weight % and 4 weight % (respectively) of the LD with the balance to 100 weight % being Product 4. These films had haze values of 5%. 6% and 5%, respectively. Three j further ■blended" films were then prepared on a larger blown film machine (having a screw extruder diameterof 3.5 inches) and tested for haze. These blends were made with Product 5 and contained only 1 weight %, WO 2004/041927 PCT/CA2003/001585 26 0.75 weight% and 0,5 weight % of the above described LD. The haze values for these films were 3%, 4% and 4%, respectively. Additional films were prepared at different film gauges (from 0.5 to 2.5 mils) using different blow up ratios (from 2 to 3). These data are not included, but the tear strengths of all films were observed to be excellent. INDUSTRIAL APPLICABILITY The novel compositions of this invention are suitable for the > preparation of a wide variety of plastic goods, especially film. TABLE B.1 RESIN 1 2 3 4 5 6 Catalyst(ppm)toR1 0.099 0.090 0.093 0.094 0.095 0.100 R1 RT1 ratio (mol/mol) 1.1 1.1 1.1 1.1 1.1 1.1 R1 AIT7 ratio (mol/mol) 65.4 65.3 65.1 65.3 200.5 65.1 R1 OH/Al ratio (mol/mol) 0.30 0.30 0.30 0.30 0.30 0.30 Catalysl(ppm)toR2 0.45 0.40 0.36 0.32 0.32 0.32 R2 BlTi ratio (mol/mol) 1.2 1.2 1.2 1.2 1.2 1.2 R2 Ai/Tl ratio (moI/mol) 45.0 45.0 45.0 45.0 0.2 45.0 R2OH/AlralIo(mol/mol) 0.30 0.30 0.30 0.30 0.02 0.300 Ethylene conc R1 (weight%) 9.2 9.4 9.4 9.5 9.3 9.4 Octeno % lo R1 80.0 60.0 59.9 60.0 80.0 97.5 Total Octane/Einylene 0.85 0.90 0.98 0.90 0.90 0.87 R1 H2 (ppm) 0.23 0.27 0.26 0.25 0.24 0.26 R2 H2 (ppm) 0.85 0.52 0.45 0.50 0.48 0.37 R1 mean temperature (ºC) 139.8 140.1 140.0 141.4 139.8 140.2 R1 out (ºC) 140.5 110.7 140.6 141.9 140.4 140.8 R1 ethylene conversion (%) 85.7 84.5 84.8 85.1 85.4 84.8 R1means temperature(ºC) 190.9 189.2 189.7 186.6 187.5 188.6 R2out (ºC) 193.3 191.7 192.0 191.4 190.4 191.7 R2 ethyene conversion (%) 92.1 90.5 88.5 88.2 88.3 90.0 R1 residence time (min) 1.0 1.1 1.0 1.0 1.0 1.0 R2 residence time (mim) 1.2 1.2 1.1 1.1 1.1 1.1 Melt lndex , (g/10 minutes) 1.2 1.1 0.9 1.1 1.1 12 Density (g/cc) 0.917 0.918 0.918 0.910 0.91 7 0.917 WO 2004/041927 PCT/CA2003/001585 27 TABLE B.2 Product Overall Composition Heterogenized Fraction Mn(x103) Mw(x103) SCB(per 1000C atoms) Weight% Mn(x103) Mn(x103) SCB(per1000C atoms) 1 24.1 93.3 15.0 8.5 76.8 130.1 3.9 4 27.8 91.7 15.1 5.3 99.3 185.1 3.1 6 28.7 91.6 14.9 5.9 67.4 165.2 2.8 TABLE C.1 1 mil Films 2.5/1 BUR 1-C 2 3 4 5 Dart Impact Strenglh (XXX) 1336 367 648 1004 1262 1335 Hoxanc Extractables (%) 0.4 0.9 0.9 0.6 0.5 0.6 MDTear(g) 255 476 347 345 343 347 TD Tear (g) 337 824 548 509 478 463 Haze(%) 20 30 27 22 32 32 Output (xxx) 100 100 100 100 100 100 Screw Speed (rpm) 37 40 40 40 39 38 Amps 54 38 36 38 39 36 Average Pressure(psl) 4885 3780 3945 3880 3945 3700 Note: Comparative film 1-C was prepared from EXCEED 1018 resin WO 2004/041927 PCT/CA2003/001585 28 CLAIMS 1. A heterogenized/homogeneous polymer composition comprising: A) a first polymer fraction having a density of from 0.880 to 0.945 grams per cubic centimeter as measured by ASTM D792; a malt index, l2 of from 0.1 to 200 grams per 10 minutes as determined byASTM D1238; less then 2 weight % hexane extractables; and a substantial absence at homopolymer wherein said first polymer fraction comprises at least one homogeneous copolymer of ethytene and at least one C4to10 alpha olefin, and wherein each of said at least one homogeneous copotymers characterized by having a molecular weight distribution, Mw/Mn, of less then three; and B) a second polymer fraction having a higher molecular weight then said first fraction; a higher density then said first fraction; and a lower alpha olefin content then said first fraction, wherein said second polymer fraction comprises at least one second homogeneous polymer of ethylene, optionally with at least one C4TO10 alpha olefin comonomer, and wherein each of said at least one second homogeneous polymer of ethylene is characterized by having a molecular weight distribution, Mw/Mn, of less 2. The polymer composition of claim 1 when prepared in a solution polymerization process using a catalyst system comprising an organometallic complex of a group 4 metal having an activity greater than 250,000 grams of polymer composition per gram of said group 4 metal. 3. The polymer composition of claim 1 wherein said second polymer 4. The polymer composition of claim 1 containing from 80 to 99 weight % of said first polymer fraction and from 1 to 20 weight % of said second polymer fraction. 5. The polymer composition of claim 4 containing from 2 to 10 weigh! % of said second polymer fraction, 6. he polymer composition of claim 1 containing less than 2 weight % hexane extractables. WO 2004/041927 PCT/CA2003/001585 29 7. The polymer cam position of claim 4 having an overall composition! density of from 0.910 to 0.940 grams per cubic centimeter as determined by ASTM D792. 8. The polymer composition of claim 1 wherein said first polymer fraction comprises at least one homogeneous copolymer of ethylene and octene-1. 9. Film prepared from the polymer composition of claim 1. 10. Film prepared from a blend of the polymer composition of claim 1 of high pressure linear low density polyethylene; heterogeneous linear low density polyethylene; heterogeneous high density polyethylene; and homogeneous linear low density polyethylene. 11. Film according to claim 10 having a thickness of from 0.5 mil to 3.0 mil; a. machine direction tear strength as determined by ASTM D1922 of greater than 300 grams per mil; and a hexane extractables content of less than 2 weight %. 12. A multilayer film structure comprising at least one layer of film according to claim 9. 13. A multilayer film structure comprising at least one layer of film according to claim 10. 14. A sealed package manufactured from a film according to claim 9. 16. A liquid package manufactured from a film according to claim 9. 17. A heavy-duty package manufactured from a film according to 18. A pallet wrap package manufactured from a film seconding-to claim 3. Novel polyethylene copolymer composition prepared with homogeneous casaly system are a characterized by hav- ing a unique high molecular weight,low comonomer(high density) fraction.These hetero(xxx) comoposition may may be prepared using asolution polymerization process in which thepolymerization reaction contain a gradient in temperature catalyst conection or monomer connection.The(xxxx)/homogeneous composition of this invention are easily processed into film having excellent (xxx)(xxx)the and low (xxxx).

Full Text

This invention relates to polyethylene compositions having a unique
balance of properties. Preferred polyethylene compositions may be easily
"processed" to produce plastic films having very good tear strength, impact
strength and optical properties.
BACK GROUND ART
Linear low density polyethylene ("LLOPE") copolymers that are
prepared by the copolymerization of ethylene with a higher alpha olefin,
using 3 conventional Ziegler-Natta type catalyst system are known to
contain three different polymer fractions (or "modes"), namely 1) a low
molecular weight fraction which contains a high comonomer content: 2) a
copolymer fraction of intermediate molecular weight and intermediate
comonomer content and 3) a high molecular weight fraction which .
contains little or no comonomer. The low molecular weight fraction is
sometimes also described as being "highly branched" (due to the high
comonomer content) and/or "grease" (due to the low molecular weight).
The high molecular weight content is also sometimes described as
"homopolymer". The "grease" traction often causes organoleptic problems
and may even limit or restrict uses in the which the polymer in contact
with food. The "homopotymer" fraction generally imparts a stiffness to the
resin and melts at a higher temperature than the other fractions. In
general, the non-uniformity of the molecular weight and the comonomer
content is a distinguishing characteristic of conventional Ziegler resins. It
In contrast, "homogeneous" polyethylene copolymers are generally
characterized by having a narrow molecular weight distribution and a
narrow composition distribution. The term "homogeneous" was proposed
by one of us to describe such polymers in United States Patent (USP)
3.645,992 (Elston), the disclosure of which is incorporated herein by-
reference.

WO 2004/041927 2 PCT/CA2003/001585
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As noted in Elston '992, homogeneous polymers have a distinct
melting point due to the uniform polymer architecture. The homogeneous
polymers disclosed in the Elston '992 patent were prepared with a
vanadium catalyst system which is insufficiently active to permit
Advances in catalyst technology now permit the production of
homogeneous ethylene eopolymers at commercially viable rates. For
example, She metallocenelaminoxane catalysts disclosed by Kamlnsky
(USP 4,542,199) and improved by Welbom (USP 5,324,800); the '
monocyclopentadienyl catalysts disclosed by Stevens et al. (USP i
5.064,802) and Canich (USP 5,055,438); the ketimine catalysts disclosed
by McMeeking et at. (USP 6,114,431); and the phosphinimine catalysts
disclosed by Stephan at al (USP 6,063,879) are all highly active for the
preparation of homogeneous copolymers.
A particularly important end use of LLDPE is the manufacture of
films. Films prepared from homogeneous LLDPE generally have good
optical properties, good organoleptic properties and excellent impact
strength.
However, films prepared from homogeneous LLDPE generally have
poor tear strength, particularly in the so-called "machine direction". In
addition, homogeneous resins are difficult to 'process" (i.e. to convert to
films). This poor processability is manifested by high energy demands
required to extrude the resin (e.g. large current draws on the electric
motors used to drive the extrudes) and/or poor melt strength-
Attempts have been made to blend heterogeneous (Ziegler-Natta,
or"Z/N") resins with homogeneous resins in order to produce a resin blend
which is easier to convert to film and/or to produce film having higher
impact strength and good tear properties. USP 5,530,065 (Farley, to
Exxon) teaches that a trivial blend of a conventional heterogeneous Z/N
resin and a metallocene resin has a balance of properties which are
suitable for some film properties. Similarly, USP 5,844,045 and 5,869,575
(Kolthamer, to Dow) also disclose that simple blends of a conventional

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heterogeneous Z/N resin and homogeneous resin prepared with a.
monocyclopentadienyl catalyst are also suitable for preparing films.
However, it will also be appreciated that the simple blends of the
above '065, '045 and '575 patents all contain the low molecular weight
"grease" due to the use of the Z/N catalyst to prepare some of the blend
composition. Moreover, the disclosures of the "065, 045 and "575 patents
are silent with respect to the hexane extractables contents of the blends.
Thus, films prepared from conventional heterogeneous resins have
comparatively poor Impact strength, optical properties and organoleptic
properties — but do have very good tear strength. Conversely, films
prepared from homogeneous resins have excellent impact strength, optical
properties and organoleptic properties-- but poor tear strength. Previous
attempts to utilize resin blends to eliminate this problem have not been
completely successful. Simple blends of heterogeneous resins with
homogeneous resins provide films with sub-optimal orcrsnoleptic
properties (presumably because of the "grease" fraction or made in the
conventional heterogeneous resin).
Another attempt to solve This problem Is by preparing blends of
more than one homogeneous resin is disclosed in USP 5.382,630. and
5,382,631 (Stehling etal, to EXXON). Stehling al. '631 teach blends
which are characterized by the substantial absence of blend components
having a higher molecular weight and a lower comonomer content than
other blend components (e.g. the high molecular weight homopolymer of
conventional heterogeneous resins. These blends are shown to be useful
-for the preparation of structures having improved tear properties,
However, the disclosure of this patent is silent on the subject of impact
suffer a very large loss of dart impact strength where the amount of lower
molecular weight higher density component is sufficient to enhance tear
strength .One of us disclosed a dual reactor solution polymerization
process to prepare a homogeneous copolymer composition which is useful
for the preparation of films (Brown, USP 6,372,864). None of the inventive

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copolymer compositions disclosed in Brown S64 contained the high
molecular weight, high density (very low comonomer) fraction which is an
Thus, Films prepared from conventional heterogeneous resins have
comparatively poor impact strength, optical properties and organoleptic I
properties - but do have very good tear strength. Conversely, films
prepared from homogeneous resins have excellent impact strength, optical
properties and organoleptic properties - but poor tear strength. Previous
attempts to utilize resin blends to eliminate this problem have not been
completely successful- Simple blends of heterogeneous resins with
homogeneous resins provide films with sub-optimal organoleptic
properties and optical properties (presumably because of the "grease"
fraction or made In the conventional heterogeneous resin),
DISCLOSURE OF INVENTION
We have now discovered a heterogenized/homogeneous polymer
composition which may be used to prepare films having an improved
balance of impact strength, tear strength and organoleptic propertis.
In addition the heterogenized/homogeneous polymer compositions
of this invention are surprisingly easy to "process" in machinery used to |
convert the compositions into films (in comparison to homogeneous
resins.
The heterogenized/homogeneous polymer compositions must be
prepared using a "homogeneous catalyst" - i.e. a catalyst system that will
produce homogeneous polymers (having a narrow molecular weight
distribution and a narrow composition distribution) In a conventional
polymerization reactor. In addition, the hetorogenized/homogeneous
polymer compositions of this invention must contain at least one first
copolymer fraction and a second high molecular weight/high density
fraction. This second fraction is somewhat analogous to the
"homopolymer" fraction of heterogeneous resins, In this sense, the
compositions may be referred to as being "heterogenized". Thus, the
polymer compositions of this Invention are made with "homogenous"

WO 2004/041927 PCT/CA2003/001585
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components prepared with a "homogeneous" catalyst system but they
must also contain a high molecular weight, high density component which
is analogous to a "heterogeneous" resin.
Thus, in one embodiment, the present invention provides a
heterogenized/homogeneous polymer composition prepared with a
homogeneous catalyst system, said composition comprising:
A) a first polymer fraction having a density of from 0.880 to
0.945 grams per cubic centimeter as measured by ASTM D792: a melt
index, (2, of from 0.1 to 200 grams per 10 minutes as determined by ASTM
D1238,- less then 2 weight % hexane extractables: and a substantial
absence of homopolyrner wherein said first polymer fraction comprises at
least one homogeneous copolymer of ethylene and at least one C4to 10
alpha olefin, and wherein each of said at least one homogeneous
copolymer is characterized by having a molecular weight distribution.
Mw/Mn, of less then three; and
B) a second polymer fraction having a higher molecular weight
then said first fraction; a higher density then said first fraction; and a lower
alpha olefin content then said first fraction, wherein said second polymer
fraction comprises at least one second homogeneous polymer of ethylene.
optionally with at least one C4to10 alpha olefin comonomer, and wherein
each of said at least one second homogoneous polymer of elthylene is
characterized by having a molecular weight distribution, Mw/Mn, of less
then 3.
As noted above, the second traction must have both of a higher
molecular weight and a lower comonomer content than the first fraction.
It will be appreciated by those skilled in the art that it is extremely
difficult to prepare such a polyrner composition by a simple mechanical
blend of the two polymer fractions. Accordingly, if is highly preferred to
prepare the present compositions by solution blending - especially via a
solution polymerization process in which the fractions are blended in situ.
It is particularly preferred to use two continuously stirred tank reactors
(CSTRs) to prepare the compositions - although a single tube reactor

WO 2004/041927 PCT/CA2003/001585
6
(plug. flow reactor) or a combination of a tube reactor and a CSTR may
also be suitably employed.
The compositions of this invention may be used to prepare a wide
variety of goods including injection molded parts, rotomolded parts and
film. Preferred compositions which are described in more detail below are
especially suitable for the preparation of films. The film may be prepared
by conventional "cast" or "blown bubble" techniques. Monolayer films or
multilayer films (prepared by coextruslon of multiple layers of laminates)
are possible. The resulting films may be used to package foods and I
consumer goods in sealed packages, including sealed packages for
Iiquid. The films are also suitable for preparing trash bags, "heavy duly
packages" (for such goods as peat moss-and other gardening items
including bark, fertilizer and decorative gravel - that are exposed to the
outdoors in gardening centers); shrink films (which may be used in high
performance packaging for poultry or cuts of meat); pallet wraps (to protect
goods on pallets during shipping and/or outdoor storage); and stretch
films.
The plastic parts and films prepared from the polymer compositions
of this invention may include conventional additives such as antioxidants
(e.g. hindered phenols and phosphates); UV stabilizers such as hindered
amines; antiblocks (e.g. talc and silica); antistatic agents (e.g. low
molecular weight polyethylene glycol); processing aids (e.g.
fluoropolymers and polyethylene glycols having a molecular weight of from
2.000 to 8,000); pigments and the like.
BEST MODE FOR CARRYING OUT THE INVENTION
Part1. (Description of Catalysts
In general, any catalyst system which produces a "homogeneous"
(as defined by Elston '922) ethylene capolymer may be used to prepare
the composition of this invention. It is preferred to use a catalyst of a
group 4 metal which provides an activity of at least 250,000 grams of
polymer per gram of group 4 metal. Preferred catalysts contain at least
one cyclopentadienyl ligand. Examples of such catalysts are disclosed in+

WO 2004/041927 PCT/CA2003/001585
7
the aforesaid Welbom '800. Stevens '802. Stephan '879 and McMeaking
'481 patents.
A preferred catalyst used In the process of this invention is an
organometallic complex of a group 3,4 or 5 metal which is characterized
by having a cyclopentadienyl ligand (as defined in section 1.3 below) and
a phosphinimine ligand(as defined in section1.2.1below)or a kitimide
ligand (as defined in section 1.2.2 below],
Any such organometallic having a phosphinimine ligand which
displays catalytic activity for ethylene polymerization may be employed.
Preferred catalysts are defined by the formula:

wherein M is a transition metal selected from 71, Hf and Zr (as described in
section 1.1 below); Cp Is a cyclopentadienyl ligand (as broadly defined in
section 1.3below);i.is a phosphimine ligand or a ketimide X is
an activatable ligand which is most preferably a simple monoanionic ligand
such as alkyl or a halide (as described in section 1.4 below); and p is one
or two depending upon the valence of M and X.
The most preferred catalysts are group 4 metal complexes in the
highest oxidation slate. For example, a preferred catalyst may be a I
cyclopentadienyl (phosphinimine) dichloride complex of titanium, zirconlum
or hafnium. It is especially preferred that the catalyst contain one
phosphinimine ligand, one cyclopentadienyl ligand, and two "X" ligands
(which are preferably both chloride),
1.1 Metals I
The preferred catalyst is an organomelallic complex of a group 3.4
or 5 metal (where the numbers refer to columns in the Periodic Table of
the Elements using lUPAC nomenclature). The preferred metals are from
group 4, (e.g. titanium, hafnium or zirconium) with titanium being most
Preferred.

WO 2004/041927 PCT/CA2003/001585
8 '
1.2.1 PhosphInlmine Ligand
A preferred catatysl contains a phosphinimlne ligand which is
covslently bonded to the metal. This ligand is defined by the formula:

wherein each R1 is independently selected from the group consisting of a
hydrogen atom, a halogen atom, C1-20 hydrocarbyl radicals which are
unsubstituted by or further substituted by a halogen atom, a C1-8 alkoxy
radical, a C6 10 aryl aryloxy radical, an amido radical, a silyl radical of the
formula:
Si-(R2)3
wherein each R2 is independently selected from the group consisting of
hydrogen, a C1-8 or alkoxy radical, C6-10 or aryloxy radicals, and , a
germanyl radical of the formula;
Ge-(R2)3
wherein R2 is as defined above.
The preferred phosphinimlnes are those in which each R1 is a
hydrocarbyl radical. A particularly preferred phosphinimine is tri-(tertiary
butyl) phosphinimine (i.e. where each R1 is a tertiary butyl group).
1.2.2 Ketirmide Ligads
As used herein, the term "ketimide ligand" refers to a ligand which;
(a) is bonded to the transmission metal via a metal-nitroge atom bond;(b)
has a single substituent on the nitrogen atom, (where this single
Substituent is a carbon atom which is doubly bonded to the N atom); and
(c) has two substituents (Sub 1 and Sub 2. described below) which are '
bonded to the carbon atom.
Conditions a,b and c are illustrated below.

WO 2004/041927 PCT/CA2003/001585
9

The substituents "Sub 1 and Sub 2" may be the same or different.
Exemplary substituents include hydrocarbyls having from 1 to 20 carbon
atoms; sllyl groups, amido groups and phosphido groups. For reasons of
cost and convenience it is preferred that these substituents both be
hydrocarbyls, especially simple alkyls and most preferably lertiary butyl.
1.3 Cycfopentadienvl Ligands i
Preferred catalysts are group 4 organometallic complexes which
contain one phosphinimine ligand or ketimide ligand and one
cyclopentadienyl ligand.
As used herein, the term cyclopentadienyl ligand is meant to
convey its broad meaning, namely a ligand having a five carbon ring which
is bonded to the metal via eta-5 bonding. Thus, the term
"cyclopentadienyl" includes unsubstituted cyclopentadienyl, substituted
cyclopentadienyl. unsubstituted Indenyl, substituted indenyt, unsubstituted
fluorenyl and substituted fluorenyl. An exemplary list of substituents for a
cyclopentadlenyl ligand includes the group consisting of C1-10 hydrocarbyl
radical (which hydrocarbyl substituents are unsubstituted or further
substituted); a halogen atom, C1-8 alkoxy radical, a C6-10aryl or aryioxy
radical; an amido radical which is unsubstituted or substituted by up to two
C1-8 alkyl radicals; a phosphido radical which is unsubstituted or
substituted by up to two C1-8 alkyl radicals; silyl radicals of the formula —Si-
(R)3 wherein each R is independently selected from the group consisting of
hydrogen, a C1-8 alkyl or alkoxy radical C6-10 arly or aryloxy radicals;
germanyl radicals of the fomula Ge—(R)3 wherein R is as defined directly
above.

WO 2004/041927 PCT/CA2003/001585
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1.4 Activatable Ligand X
The term "activatable llgand" refers to a llgand which may be
activated by a cocafalyst (also referred to as an "activator"). to facilitate
olefin polymerization. Exemplary activatable ligands are independently
selected from the group consisting of a hydrogen atom, a halogen atom, a
C1-10 hydrocarbyl radical, a C1-10 alkoxy radical, a C5-10 aryl oxide radical:
each of which said hydrocarbyl, alkoxy, and aryl oxide radicals may be
unsubstituted by or further substituted by a halogen atom, a C1-8 alkyl
radical, a C1-8 alkoxy radical, a C6-10 aryl or aryloxy radical, an amldo
radical which is unsubstituted or substituted by up to two C1-8 alkyl
radicals; a phosphldo radical which is unsubstituted or substituted by up to
two C1-8 alkyl radicals.
The number of activatable llgands depends upon the valency of the
metal and the valency of the activatable ligand. For example, a single
divalent activatable ligand (such as butadiene) may be used with a group 4
metal in the 4* oxidation slate. The preferred catalyst metals are group 4
metals in their highest oxidation slate (i.e. 4') and the preferred activatable
ligands are monoanionic (such as a halide - especially chloride or a alkyl -
especially methyl). Thus, the preferred catalyst contain a phosphinimlne
ligand, a cyclopentadienyl ligand and two chloride (or methyl) ligands
bonded to the group 4 metal. In some instances, the metal of the catalyst
component may not be in the highest oxidation state. For example, a I
titanium (111) component would contain only one activable ligand. |
1.5 Summary Description of Preferred Catalyst
As previously noted, The most preferred catalyst is a group 4
organometallic comptex in its highest oxidation state having a
phosphinimine ligand, a cyclopentadienyl-type ligand and two activatable
ligands. These requirements may be concisely described using the
following formula for the preferred catalyst:

-WO 2004/041927 PCT/CA2003/001585
11

wherein (a) M is a metal selected from Tl Hf and Zr, (b) Pl is a
phosphinimine ligand defined by the formula;

wherein each R is independently selected from the group consisting of .$
hydrogen atom, a halogen atom, C1-20hydrocarbyl radicals which are
unsubstituted by or further substituted by a halogen atom, a C1-8 alkoxy
radical, a C6-8 ARLY or aryloxy radical, an amido radical, a silyl radical of the
formula:
S-(R2)3
wherein each R2 is Independently selected from the group consisting of
hydrogen, a C1-8 alkyl or alkoxy radical, C6-10 aryl or aryloxy radicals, and,a
germanyl radical of the formula:
Ge-(R2)3
wherein R2 is as defined above: (c) Cp is a ligand selected from the group.
consisting of cyclopentadienyl. substituted cydopentadienyl, indenyl,
substituted indenyl, fluorenyl. substituted fluorenyl; and (d) each X is an
activatable ligand.
2. Description of Cocatalyst
The catalyst components described in part 1 above are used in
combination with at least one cocatalyst (or "activator") to form an active
catalyst system for oletin polymerization. Preferred activators are
decribed in more deatail in section 2.1and 2.2 below.
2.1 Alumoxane
The alumoxane may be of the formula:
(R4)2AIO(R4AIO)mAl(R4)2
wherein each R4 is independently selected from the group consisting of
C1-20 hydrocarbyl radicals and m is from 0 to 50, preferably R4 is a C1-8

-WO 2004/041927 PCT/CA2003/001585
12
alkyl radical and m is from 5 to 30. Mathylalumoxane (or "MAO") in which
each R is methyl is the preferred alumoxana.
Alumoxanes ara well known as cocatalysts, particularly for
metallocene-type catalysts. Alumoxanes are also readily available articles
The use or an alumonxane cocatalyst generally requites a molar ratio
of aluminum to the transition metal in the catalyst from 20:1 lo 1000:1.
Preferred ratios are from 50:1 to 250:1.
Commercially available MAO typically contains free aluminum alkyl
(e.g. trimethylaluminum or "TMA") which may reduce catalyst activity
and/or broaden the molecular weight distribution of the polymer. If a
narrow molecular weight distribution polymer is required, jt is preferred to
treat such commercially available MAO with an additive which is capable
of reading with the TMA. Alcohols are preferred (with hindered phenols
being particularly preferred) for this purpose. I
2.2 "Ionic Activators' Cocatalysts '
So-called 'ionic activators" are also well known for metallocene
catalysts. See, for example. USP 5.198,401 (Hlathcy and Tumer) and USP
5.132,380 (Stevens and Neilhamer).
Whilst not wishing to be bound by any theory, it is thought by those
skilled in the art that "ionic activators" initially cause the abstraction of one
or more of the activatable ligands In a manner which ionizes the catalyst
into a cation, then provides a bulky, labile, non-coordinating anion which
stabilizes the catalyst in a cationic form. The bulky, non-coordinating
anion permits olefin polymerization to proceed at the cationic catalyst
center (presumably because the non-coordinating anioin is sufficiently
labile to be displaced by monomer which coordinates to the catalyst.
(i) - (iii) below.
(i) compounds of the formula [R5]'B(R7)4]'wherein B is a
boron atom, R5- is a aromatic hydrocarbyl (e.g. triphenyl methyl cation) and
each R7 is independently selected from the group consisting of phenyl'

WO 2004/041927 PCT/CA2003/001585
13
radicals which are unsubstituted or substituted with from 3 to 5
substituents selected from the group consisting of a fluorine atom, a C1-4
alkyl or alkoxy radical which is unsubstituted or ubstituied by a fluorine
atom; and a silyl radical of the formula S-(R9)3; wherein each R9 is
independently selected from the group consisting of a hydrogen atom and
a C1-4 alkyl radical; and
(ii) compounds at the Fomula [(R8) ZH][B(R7)4] wherein B is a
boron atom, H is 3 hydrogen atom,Z is a nitrogen atom or phosphorus
atom, t Is a or 3 and R8 is selected from the group consisting of C1-8 alkyl
radicals, a phenyl radical which is unsubstituted or substituted by up to
three C1-4 alkyl radicals, or one R8 taken together with the nitrogen atom
may form an anillnium radical and R7 is as defined above; and
(iii) compounds of the formula B(R7)3 wherein R7 is as detined
above.
In the above compound preferably R7 is a pentafluorophenly
radical, and R5 is a Iriphenylmethyl cation, Z is a nitrogen atom and R8 is a
C1-4 alkyl radical or R8 taken together with the nitrogen atom forms an
anilinium radical which is substituted by two C1-4 alkyl radicals.
The"ionic activator "may abstract one or more activatabte ligands
so as to ionizing catalyst center into a cation but not to covalenlly bond
with the catalyst to provide sufficient distance between the catalyst
and the ionizig active to permit a polymerizable olefin to enter the
resuliting active site.
Example of ionic activators include
triothylamonium tetra (phenyl)boron.
triprophylamnium tetra(pheny))boron,
(n-buthyl)ammonium tetra(phenyl)borun,
trimethlammonium tetra(p-tolyl)boron,
trimethylammonium tetra(O-tolyl)boron,
trimethylammonium tetra(pentafluorohenyl)boron.
trimethylammonium tetra(o.p-dimethylphenyl)boron,
trimethylammonium tetra(m.m-di methyl phenyl ]boron,

WO 2004/041927 PCT/CA2003/001585
14
tributhylammonium tetra(p-triuoromethyphenyl)boron
tributylammonium tetra(pentafluorophenly) boron
tri(n-butyl)ammonium tetra (o-tolyl) boron
N,N-diethylanllinium tetra(phenyl)boron,
N,N-diethylanllinium tetra(phenyl)boron,
N,N-diethylanllinium tetra(phenyl)boron,
N,N-2,4,6 pentamethylanilinium tetra(phenyl)boron,
di-(isoproprophyl)ammonium tetra(pentraflourophenthore,
dicyclohexlammonium tetra(phenyl)boron
tri(methylphenyl)phosphonium tetra(phenyl)boron
tri(methylphenyl)phosphonium tetra(phenyl)boron
tri(methylphenyl)phosphonium tetra(phenyl)boron
tropillium tetrakispenta fluorophenyl borate,
triphenylmethyllium phenyttrispentalfluorophenyly borate,
benzene(diazonlum) tetrakispenta fluorophenyl borate
tropllium phenyltriphenyt trispentalfluorophenly borate
tropillium tetrakls (2,3,5,6-terafluorophenyl) borate,
benzene(diazonlum) tetrakispenta (3,5,6-terafluorophenyl) borate,
tropillium tetrakis(,3,4,5trispentalfluorophenly )borate
benzene(diazonlum) tetrakis (3,4,5 fluorophenyl) borate
tropillum tetrakis (1,2,,2trispentalfluorophenly)borate
tributhylammonium tetrakis (1,2,2trispentalfluorophenly)borate
benzene(diazonlum) tetrakispenta (1,2,2-tetrafluorophenyl) borate
tropillium tetrakis(2,3,4,5trispentalfluorophenly )borate
triphenylmethylium tertrakis (2,3,4,5 tetrafluorophenyl) borate
benzene(diazonlum) tetrakis (,2,3,4,5-tetrafluorophenyl) borate
Readily commercialy available ionic activators includes
N N-diamethylaluminutetetrakispentaflurophenyl borate.
triphenylmethylium tetrakispentafluophenyl borate and

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15
trispenfafluorophenyl borane.
3. Description of Dual Reactor Solution Polymerization Process
Solution processes for the (colpolymarization of ethylene are well
knowin that art.These processes are conduted in the presence of an
inert hydrocarbon sovent(typicaliy a C5-12 hydrocarbon which, which be
unsiib5tr(uied or substituted by a CM affcyf group, such as pentane, methyl
perrtane. fiexane, heptane, octane, cycfofiexane. mefliycyctafiexane and
hyrirogenated naphtha. An example of a suitable solvent which is
commercially available is "(sopar p (CIM? aliphatic solvent, Exxon
Chemical Co.).
The preferred solution polymerisation process for this invention
uses at least two pdymsrisJEion rssctors-
The pc!yTrreri2a8an tempef^ftire i^i [Ire rrrsf rvzetof Is Itatn abof/f
SO°C to about iflO°C (pnsferaWv from about !EO"C to ISO'CJ ancf ifve
second reactor Is preferably operated at a higher terrro^rafure (4/p fo sfcaut
220°C). The most prefened rescfon process is a "medium pressure
pmcess', rrwaning that trie pressure in eacft reactof is prefersWy less ^arr
about 6,000 psi (about A 2,000 kitoPzscais or kPa), most preferably from
si?out 2,000 psi to 3,000 psi (about 14.000-22.000 JfPa).
SuSaWe monomers for copolymerization with ethylene include XXX
ajpha olefins. Pi&f&ired comonomeis 'mciuOs alpha o}&liri$ which sas
uxissjbstituled Of substituted i?y yp io hw^ C?.§ sJJcyi fadir^Js. WJusfis^ve
non-Jimilin0 exampJes Of such ^^ph^-c^lefi^s are one or more of propyfe^e,
1-buteoe. 1-peuIene, 1-hexene, 3-octerjeand 1-derene.
The heterogeneous/homogeneous copolymer compositions which
may be prepared in accordance with the present invention are preferably
U-DPE'S which typically comprise not less than 60, preferably not less
than 75 weight % of ethylena and the balance one or more C*-«, alpha
oleiins, preferably selected from the group consisting of 1-butene. 1-
hexane and 1-octene. The polyethylene prepared in accordance with the
present invention may be LLDPE having a density from about 0.910 to
0.93G glee or [linear) high density polyethylene having a density above

WO 2004/041927 PCT/CA2003/001585
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0.935 glce. The present invention might also be useful to prepare
polyethylene having a density below 0,910 g/cc - the so-called very low
and ultra low density polyetiiylenes.
Generally (he alpfra olefin may be present in an amount from about
3 to 30 weight %. preferably from about 4 to 25 weight %.
The monomers are dissolved/dispersed in the solvent either prior to
being fed to the first reactor (or for gaseous monomers the monomer may-
be fed to the reactor SD that it will dissolve in the reaction mixture). Prior to
mixing, the solvent and monomers are generally purified to remove
potential catalyst poisons such as water, oxygen or metal impurities. The
feedstock purification follows standard practices in the art, e.g. molecular
sieves, alumina beds and oxygen removal catalysts are used for the
purification of monomers. The solvent itself as well (e.g. methyl pentahe,
cyctohexsne, hexann or toluene) is preferably treated in a similar manner.
Tha feedstock may be heated or cooled prior to feeding to the first
reactor. Additional rnonomers and solvent may be added to the second
reactor, and it may be heated or cooled.
Generally, the catalyst components may be premised in the solvent
for the reaction orfed as separat stream to each reactor.In some
Instances premixing it may be desirable to provide a reaction time for the
catalyst components prior to entering the reaction. Such an in line
mixing" technique is described in a number of patents in the name of
DuPont Canada Inc (e.g. USP 5.589,555, issued December 31,1996).
The residence time in each reactor will depend on the design and
the capacity of the reactor. Generally the reactors should be operated
under conditions to achieve good mixing of the reactants. In addition, it is
preferred that from 20 to 60 weight % of the final polymer is polymerized In
the first reaclor, with the balance being polymerized in the second reactor.
On leaving the reactor system the solvent is removed and the resulting
polymer is finished in a conventional manner.
In a highly preferred embodiment, the first polymerization reactor
has a smaller volume than the second polymerization reactor. In addition

WO 2004/041927 PCT/CA2003/001585
17
the first polymerization reactor is preferably operated at a colder
temperature than the second reactor.
Preferred Polymer Compositions
Polyethylene resins are often converted to finished products by a
melt extrusion process. Extrusion processes generally produce more
"drawdown" of the polyethylene melt in the machine direction (MD) than
the transverse direction (TD) due to the force which is required to "draw
the melt through the extrusion die. This typically produces a finished
plastic part with unbalanced mechanical properties which vary with the
orientation or direction of measurement A common example of this
phenomenon is illustrated by considering an injection molded plastic cup.
These cups are usually fabricated by forcing the plastic melt through an
Injection port at the base of the cup mold thus producing a flow from the
base of the cup to the lip of the cup in a lengthwise direction. The finished
plastic cup therefore has a "machine direction" along the length of the cup
and is more prone to split or tear in this lengthwise direction (i.e. the cup is
less prone to fail around the circumference or "transverse direction").
An analogous phenomenon is observed with polyethylene films.
That is, extiuded plastic films generally have poor "machine direction" tear
strength in comparison to transverse directionh tear slrength.This may be
referred to as a tear strength imbalance. It has been observed that this
effect (i.e. MD vs. TD tear Imbalance) becomes more pronounced in films
prepared from heterogeneous ethylene-butene copolymers as the
molecular weight of the copolymer increases. That is, the relative MD vs.
TD imbalance becomes more pronounced in films prepared from higher
molecular weight heterogeneous copolymers. While not wishing to be
bound by theory, it is postulated that this phenomenon is a result of the
greater stress which is required to extrude the higher molecular weight
copolymer (which in turn gives rise to a higher orientation of the polymer
molecules and thereby causes a higher MD/TD imbalance).
This phenomenon has also been observed to become even more
pronounced with homogeneous resins. While again not wishing to be

WO 2004/041927 PCT/CA2003/001585
18
bound by theory, it is believed that the uniform structure of a
homogeneous resin causes the polymer molecules to be very uniformly
oriented during melt extrusion. In any event, the MD tear of films prepared
from homogeneous polymers is generally very poor. However, the impact
strength of films prepared from homogeneous polymers is usually
excellent.
As previously noted, It is Known to prepare homogeneous ethylene
polymer compositions in which a fraction or blend component of the |
composition contains a higher density but lower molecular weight then the
other polymer fraction (e.g. me Stehting et al. '631 patent and the
commercially available EXCEED™ 1016 resin).
In contrast, the compositions of this invention must contain a
second" polymer fraction which is both higher molecular weight and
higher density (or alternatively stated, "less branched') than the first
copolymer fraction. It is preferred that this high molecular weight/high
density fraction be present in an amount of from 1 to 20 weight %,
especially from 2 to 10 weight %, of the total polymer composition. It is
also preferred that the high molecular weight/high density fraction has less
than 5, especially less than 4, short branches per 1,000 carbon atoms. It
is further preferred that the high molecular weight/high density fraction has
a weight average molecular weight, Mw.of from 130.000 to 500,000,
especially more than 150,000 to 500.000.
The "first" fraction of the polymer compositions of this invention
contains at least one homogeneous copolymer. The first fraction may
contain more than one homogenous copolymer but this is not necessary.
The heterogenrzed/homogenous compositions of this invention are
especially suitable for the preparation or films. It is preferred that films
prepared from a heterogenized/homegenous composition have an overall
density or from 0.900 to 0.940 g/cc (especially from 0.90B to 0.920) and ar|
overall melt index. I2 of from 0.3 to 20.

WO 2004/041927 PCT/CA2003/001585+
19
EXAMPLES I
Part 1. Comparative Examples
A sample of commercially available resin sold under the trademark
EXCEED™ f 1019CA by ExxonMobil Chemical was subjected to a gel
permeation chromatography (GPC) analysis to determine molecular
weight distribution and a temperature rising elation fractionation (TREF)1
analysis. Trichlorobenzene was used as the mobile liquid phase for the
TREF analysis. The GPC analysis is described in Part 2 below.
The EXCEED™ 1018CA resin is reported to be an ethylene-hexene
copolymer produced using ExxonMobil Chemicals' EXXPOL™ technology
(which is believed to be a metallocena catalyst technology).
The TREF analysis of this resin showed two distinct elution peaks-
The first peak - indicative of a homogeneous copolymer fraction —was
observed at 80.7ºC. A second fraction having less comonomsr (high
density fraction) was observed to elute at 93.1°C.
GPC analysis of the whole resin showed the weight average
molecular weight (Mw) to be about 101,000 and the molecular weigh!
distribution to be about 2.1.
according to elution temperature (using a conventional TREF preparation
technique with trichlorobenzene as the moblie liquid phase solvent). The
high density fraction (or cut), which eluted at a temperature of from so to
95°C, was observed to be about 8.5 weight % of the total polymer |
composition. This fraction was analyzed to have a weight average I
molecular weight of 72,000. Thus, this sample of EXCEED™ 1018CA is
consistent with the disclosure of ths aforesaid Stehling et al. '630 patent
because the 'high density" fraction has a toner molecular weight than the
conolymer fraction (i.e. 72,000 vs. 101,000). One mil films prepared from
EXCEED™ 1O1BCA (on a blown film line having a 60 mil die gap, using a
2.5:1 blow up ratio) are reported by ExxonMobil Chemical to have (typical)

WO 2004/041927 PCT/CA2003/001585
20
dart impact strength of 740 grams, machine direction (MD) tear strength of
260 gratis, and transverse direction (TD) tear strength of 340 grams.
Comparative Example
An ethylene-octene copolymer having a density of 0.917 grams per
cubic centimeter (g/cc) and a molecular weight distribution (Mw/Mn) of 18-
was prepared in a solution polymerization process using a titanium
catalyst having one cyclopentadienyl ligand, one tri(terllary butyl)
phosphinimine ligand and two chloride ligands (referred to hereinafter as.
CpTiNP(t-Bu)3Cl2) and an activator consisting of a commercially |
available methyl aluminoxane ("MAO") at an A/Ti mole ratio of 100/1 and'
triphenyimethylium tetra kispentafluorophenyl borate ("Ph3CB(C6F5)4") at a
Bm mole ratio of 1.2/1.
The resulting copolymer did not contain a very high density/higher
melting point fraction In any meaningful amount. ,
A blown film having an average thickness of 1 mil was prepared
using a conventional extruder al a blow up ratio of 2.5/1 through a 3.5 mil
die gap.
The resulting film had a dart impact of greater than 1,000 grams, a
machine direction tear strength of 250 grams and a transverse direction
tear strength of 340 grams.
Part2 Inventive Polymerizations
The examples illustrate the continuous solution copolymerization of
ethylene and octene at medium pressure. The Inventive examples used a
first continuously stirred tank reactor ("CSTR") which operated at a
relatively low temperature (see Table B.1). The first reactor pressure was
about 14.5 Mega Pascals, and the second reactor pressure was
marginally lower (to facilitate flow from the first to second reactor). The
contents from this reactor flowed into a larger, second polymerization
reactor which was also a CSTR. The volume of reactor 2 was 1.8 times
larger than the volume of reactor 1.
The process was continuous In all "feed streams (i.e. solvent, which
was methyl pentane; monomers and catalyst systems) and in the removal

WO 2004/041927 PCT/CA2003/001585
21
of product monomer were purified prior to addition to the reactor using
conventional feed preparation systems (such as contact with various
absorption media to remove impurities such as water, oxygen and polar
contaminates).
Feeds (monomers, catalysts, activators) were pumped to the
reactors as shown in Table B.1. Average residence times for the reactors
were calculated by dividing average flow rates by reactor volume. The I
residence time in each reactor for all of the inventive experiments was less
than 1.5 minutes and the reactors were well mixed. While not wishing to
be bound by theory, it is believed that the short residence time of the
inventive polymerization reads to small temperature. catalyst and/or
monomer concentration gradients which cause the formation of the high
molecular weight/high density polymer component which is essential to the
compositions of this invention.
The catalyst used in all experiments was a titanium (IV) complex I
having one cyclopentadienyl ligand, two chloride ligands and one tri |
(tertiary butyl) phosphinimine ligand (-CpTiNP(Bu)3Cl2"). The cocatalysls
were a commercially available methylalumoxane ("MAO") and a
commercially available borate ('Ph3CB(C6F5)4-). A hindered phenol (2,6
di-tertiary butyl, 4-ethyl, phenol) was also used as shown in Table B.1.
The amount of catalyst added to each reactor(expressed as parts
per million (ppm) by weight, based on the total mass of the reactor
contents) as shown in Table B1. The MAO. borate and phenol were
added in the amounts shown in Table B.I. The amount of MAO
(expressed as moles of Al per mole of Ti (in the catalyst)), berate
(expressed as moles of 8 per mol of Ti) and moles of phenol (expressed
as moles of OH per mole of Al in the MAO) is shown in Table 8.1 where
"R1" refers to reactor 1 and "R2" refers to reactor 2.
The ethylene concentration in reactor 1 ( R1") is expressed as
weight %. An equivalent flow of ethylene was provided to each reactor.
The total amount of octene used in both reactors is reported in ■
TableB.1 based on the total amount of ethylene (mole/mole basis). The

WO 2004/041927 PCT/CA2003/001585
22
fraction of the oclene added to R1 is shown in Table B.1 (with the
remaining octene being added to the second reactor *R2"), I
Hydrogen was added to the reactors in small amounts as shown in
Table B.1 (expressed as ppm by weight).
(For clarification: Table B.1 shows that the first composition, was
prepared using the following average conditions in reactor 1 (R1"); I
catalyst concentration of 0.099 ppm;boron/Ti=1.1 (mol/mol): AUi-65A
(mol/mol); OHAI=0.3 (mol/mol); ethylene concentration=9.2 weight %:
80% of the total octene added toR1 and R2 was added to R1; the total
oetenefethylene mole ratio was D.B5; the hydrogen concentration was 0.23
ppm by weight in R1; the mean R1 reactor temperature was 139.8°C and
the residence time was 1.0 minutes).
The composition of the monomer feeds and the position of the
monomer feed port(s) relative to the catalyst feed port in the second
reactor R2 was varied to examine the effect of these variables upon the
microstructure of the heterogenized homogeneous compositions of this
invention.
The feed ports to reactor 1 were not adjusted for any of the
experiment .One feed port was used to add ethylene and octene In
solvent and another feed port was used for all of the catalyst components
added to R1.
The entry port into reactor R2 for the polymer solution from R1 was
not changed for any of the experiments shown inTable B.1 — it was
located on one side of the reactor about midpoint between the top and
bottom. The first product (entry 1 in Table B.1) was prepared by feeding
the fresh monomer and catalyst at the bottom of the reactor R2 through
separate feed lines.
Product 2 was prepared by moving the fresh monomer feed to the
side of reactor.
Product 3 to 6 were prepared using "split fresh monomer feed"i:e.
through two nozztes on theside of the reactor. Cocatalyst flows and

WO 2004/041927 PCT/CA2003/001585
23
hydrogen flows were also changed for Products 3 to 6 as shown in Table
B.1.
Polymer properties were measured using test methods described
below
Melt index ("Ml") measurements are conducted according to ASTM
method D-1238.
Polymer densities are measured using ASTM 0-1928.
Molecular weights were analysed by gel permeation
chromatography (GPC), using an Instrument sold under the tradename
'Waters 150c",with 1,2.4-trichlorobenzene as the mobile phase at
140°C. The samples were prepared by dissolving the polymer in this
solvent and were run without filtration. Molecular weights are expressed
as polyethylene equivalents with a relative standard deviation of 2.9% for
the number average molecular weight ("Mo") and 5.0% for the weight
average molecular weight ("Mw").
Film properties were measured using the following test methods'
Haze (ASTM D-1003);
Gloss (ASTM D-2457);
MD Tear and TD Tear Resistance (ASTM D-1922); '
Dart Impact Strength (ASTM D-1709); and '
Hexane Extraetables (Complies with U.S. Food
and Drug Administration (FDA) test set out in the Code of Federal
Regulations Title 21. Parts 177.1520. In general, a film sample is
extracted in hexane at 50°C for2 hours.)
Melt index, l2, and density data for each of the heterogenized
homogeneous compositions are also given in Table B.1,
TREF and GPC analysis of Products 1,4 and 6 was then
completed. Product 1 was expected to be most "heterogenized" (due to
the previously discussed locations of the fresh monomer feed and catalyst
ports).
Product 1 had an Mw of 93,300; an Mn of 24,000; and an average
of 15 short chain branches per 1,000 carbon atoms. 91.5 weight % of the
composition eluted at the lower temperatures expected for homogeneous
copolymers. However, 8.5 weight % of Product 1 eluted over a higher)

WO 2004/041927 PCT/CA2003/001585
24
temperature range of from 88 to 110°C. This fraction had an Mw of
130,400 and only 3.9 branches per 1,000 carbon atoms -thus, it was
higher molecular weight and lower comanomer content (higher density)
than the remainder of the composition. These data are shown in Table
B.2, together with analogous date for Product 4 and 6 (from the
polymerization examples). In Table B.2, *SCB refers to the number of
short chain branches per 1000 carbon atoms. A low SCB figure indicates
a low amount of comonomer.
The term "heterogenized fraction" in Table B.2 refers to the high
molecular weight, high density component which elutes at a temperature
of the total heterogeneous/homogeneous composition. For clarity, the
data in Table B.2 show that Product 1 contained 8.5 weight % of the high
density/high molecular weight, low comonomer content material and
Product 6 contained 5.9 weight %. '
Part 3. Film Preparation
Films were prepared from compositions 1 to 6 which ware prepared
in the polymerizations observed above. A comparative film was also made
using the previously described commercially available EXCEED™ 1018 I
product The films were manufactured on a conventional blown film line
which was fed by a single screw extruder having a 3.5 inch screw
diameter. The extruder was driven by an electrical motor. Conventional
additives (antioxldants and process aid) were added to all extrusions. The
extrudate was forced through a circular die having a four inch diameter
and a 35 mil die gap. A blow up ratio (BUR) of 25:1 was used to prepaid
the film. Other processing conditions (output, head pressure and motor |
toad) are shown in Table C.1. Referring to Table C1.it can be seen that I
the electrical power demand required to drive the extruder is expressed as
a current load on the motor (expressed in amps) to produce a given film
output (expressed in pounds of film per hour). The electrical demand for
the product from experiment 1-C was 54 amps for a 100 Ibs/hr throughput
(in comparison to 36-39amps for the inventive composition). Thus, the

WO 2004/041927 PCT/CA2003/001585
25
comparative LLDPE of experiment 1-C has poor "processability" (as
indicated by load or the electrical motor).
Physical properties of the films are shown inTableC.1!. The
"hexane extractables" content of all films is very low. This is a very
desirable feature of films mads from a homogeneous catalyst system.
The comparative film 1-C had a very high dart impact strength but
tear properties. [Note that the "dart" impact strength of 1,226 g is
significantly higher than the typical" value of 740 reported by the resin
manufacturer — as discussed in Part 1 above. However, the MD and TD
tear strength numbers shown in Table C.1 (255 g and 337 g) correspond
very closeiy to the -typical- values (MD=260 g, TD=340 g) reported by the
manufacturer of the EXCEED™ 1018 resin.] All of the inventive
compositions 2 to 6 have significantly improved tear strengths. Moreover,
the films made from heterogeneous/homogeneous- resins 4 to 6 also
exhibit very good impact strength, |
It will also be noted that the "haze" values of all of the films I
prepared on this machine were not very impressive. Additional
experimentation showed that the haze values could be greatly improved
by blending some high pressure low density ("LD") resin or conventional
(heterogeneous) linear low density resin with the inventive resins. Blends
of up to 40 weight % of the LD or heterogeneous LLDPE resins may be
used to improve haze results and amounts as low as 0.25 to 3.00 weight
For example, three blends of a high pressure, low density
polyethylene "LD" (having a density of 0.921 g/cc and a melt index,|l2, of;
The three blends contained 2 weight %, 3 weight % and 4 weight %
(respectively) of the LD with the balance to 100 weight % being Product 4.
These films had haze values of 5%. 6% and 5%, respectively. Three j
further ■blended" films were then prepared on a larger blown film machine
(having a screw extruder diameterof 3.5 inches) and tested for haze.
These blends were made with Product 5 and contained only 1 weight %,

WO 2004/041927 PCT/CA2003/001585
26
0.75 weight% and 0,5 weight % of the above described LD. The haze
values for these films were 3%, 4% and 4%, respectively.
Additional films were prepared at different film gauges (from 0.5 to
2.5 mils) using different blow up ratios (from 2 to 3). These data are not
included, but the tear strengths of all films were observed to be excellent.
INDUSTRIAL APPLICABILITY
The novel compositions of this invention are suitable for the >
preparation of a wide variety of plastic goods, especially film.
TABLE B.1
RESIN 1 2 3 4 5 6
Catalyst(ppm)toR1 0.099 0.090 0.093 0.094 0.095 0.100
R1 RT1 ratio (mol/mol) 1.1 1.1 1.1 1.1 1.1 1.1
R1 AIT7 ratio (mol/mol) 65.4 65.3 65.1 65.3 200.5 65.1
R1 OH/Al ratio (mol/mol) 0.30 0.30 0.30 0.30 0.30 0.30
Catalysl(ppm)toR2 0.45 0.40 0.36 0.32 0.32 0.32
R2 BlTi ratio (mol/mol) 1.2 1.2 1.2 1.2 1.2 1.2
R2 Ai/Tl ratio (moI/mol) 45.0 45.0 45.0 45.0 0.2 45.0
R2OH/AlralIo(mol/mol) 0.30 0.30 0.30 0.30 0.02 0.300
Ethylene conc R1 (weight%) 9.2 9.4 9.4 9.5 9.3 9.4
Octeno % lo R1 80.0 60.0 59.9 60.0 80.0 97.5
Total Octane/Einylene 0.85 0.90 0.98 0.90 0.90 0.87
R1 H2 (ppm) 0.23 0.27 0.26 0.25 0.24 0.26
R2 H2 (ppm) 0.85 0.52 0.45 0.50 0.48 0.37
R1 mean temperature (ºC) 139.8 140.1 140.0 141.4 139.8 140.2
R1 out (ºC) 140.5 110.7 140.6 141.9 140.4 140.8
R1 ethylene conversion (%) 85.7 84.5 84.8 85.1 85.4 84.8
R1means temperature(ºC) 190.9 189.2 189.7 186.6 187.5 188.6
R2out (ºC) 193.3 191.7 192.0 191.4 190.4 191.7
R2 ethyene conversion (%) 92.1 90.5 88.5 88.2 88.3 90.0
R1 residence time (min) 1.0 1.1 1.0 1.0 1.0 1.0
R2 residence time (mim) 1.2 1.2 1.1 1.1 1.1 1.1
Melt lndex , (g/10 minutes) 1.2 1.1 0.9 1.1 1.1 12
Density (g/cc) 0.917 0.918 0.918 0.910 0.91 7 0.917

WO 2004/041927 PCT/CA2003/001585
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TABLE B.2
Product Overall Composition Heterogenized Fraction
Mn(x103) Mw(x103) SCB(per 1000C atoms) Weight% Mn(x103) Mn(x103) SCB(per1000C atoms)
1 24.1 93.3 15.0 8.5 76.8 130.1 3.9
4 27.8 91.7 15.1 5.3 99.3 185.1 3.1
6 28.7 91.6 14.9 5.9 67.4 165.2 2.8
TABLE C.1
1 mil Films
2.5/1 BUR
1-C 2 3 4 5
Dart Impact Strenglh (XXX) 1336 367 648 1004 1262 1335
Hoxanc Extractables (%) 0.4 0.9 0.9 0.6 0.5 0.6
MDTear(g) 255 476 347 345 343 347
TD Tear (g) 337 824 548 509 478 463
Haze(%) 20 30 27 22 32 32
Output (xxx) 100 100 100 100 100 100
Screw Speed (rpm) 37 40 40 40 39 38
Amps 54 38 36 38 39 36
Average Pressure(psl) 4885 3780 3945 3880 3945 3700
Note: Comparative film 1-C was prepared from EXCEED 1018 resin

WO 2004/041927 PCT/CA2003/001585
28
CLAIMS
1. A heterogenized/homogeneous polymer composition comprising:
A) a first polymer fraction having a density of from 0.880 to
0.945 grams per cubic centimeter as measured by ASTM D792; a malt
index, l2 of from 0.1 to 200 grams per 10 minutes as determined byASTM
D1238; less then 2 weight % hexane extractables; and a substantial
absence at homopolymer wherein said first polymer fraction comprises at
least one homogeneous copolymer of ethytene and at least one C4to10
alpha olefin, and wherein each of said at least one homogeneous
copotymers characterized by having a molecular weight distribution,
Mw/Mn, of less then three; and
B) a second polymer fraction having a higher molecular weight
then said first fraction; a higher density then said first fraction; and a lower
alpha olefin content then said first fraction, wherein said second polymer
fraction comprises at least one second homogeneous polymer of ethylene,
optionally with at least one C4TO10 alpha olefin comonomer, and wherein
each of said at least one second homogeneous polymer of ethylene is
characterized by having a molecular weight distribution, Mw/Mn, of less
2. The polymer composition of claim 1 when prepared in a solution
polymerization process using a catalyst system comprising an
organometallic complex of a group 4 metal having an activity greater than
250,000 grams of polymer composition per gram of said group 4 metal.
3. The polymer composition of claim 1 wherein said second polymer
4. The polymer composition of claim 1 containing from 80 to 99 weight
% of said first polymer fraction and from 1 to 20 weight % of said second
polymer fraction.
5. The polymer composition of claim 4 containing from 2 to 10 weigh!
% of said second polymer fraction,
6. he polymer composition of claim 1 containing less than 2 weight %
hexane extractables.

WO 2004/041927 PCT/CA2003/001585
29
7. The polymer cam position of claim 4 having an overall composition!
density of from 0.910 to 0.940 grams per cubic centimeter as determined
by ASTM D792.
8. The polymer composition of claim 1 wherein said first polymer
fraction comprises at least one homogeneous copolymer of ethylene and
octene-1.
9. Film prepared from the polymer composition of claim 1.
10. Film prepared from a blend of the polymer composition of claim 1
of high pressure linear low density polyethylene; heterogeneous linear low
density polyethylene; heterogeneous high density polyethylene; and
homogeneous linear low density polyethylene.
11. Film according to claim 10 having a thickness of from 0.5 mil to 3.0
mil; a. machine direction tear strength as determined by ASTM D1922 of
greater than 300 grams per mil; and a hexane extractables content of less
than 2 weight %.
12. A multilayer film structure comprising at least one layer of film
according to claim 9.
13. A multilayer film structure comprising at least one layer of film
according to claim 10.
14. A sealed package manufactured from a film according to claim 9.
16. A liquid package manufactured from a film according to claim 9.
17. A heavy-duty package manufactured from a film according to
18. A pallet wrap package manufactured from a film seconding-to
claim 3.

Novel polyethylene copolymer composition prepared with homogeneous casaly system are a characterized by hav-
ing a unique high molecular weight,low comonomer(high density) fraction.These hetero(xxx) comoposition may
may be prepared using asolution polymerization process in which thepolymerization reaction contain a gradient in temperature catalyst
conection or monomer connection.The(xxxx)/homogeneous composition of this invention are easily processed into
film having excellent (xxx)(xxx)the and low (xxxx).

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Patent Number

216041

Indian Patent Application Number

00758/KOLNP/2005

PG Journal Number

10/2008

Publication Date

07-Mar-2008

Grant Date

06-Mar-2008

Date of Filing

29-Apr-2005

Name of Patentee

NOVA CHEMICALS (INTERNATIONAL) S.A.

Applicant Address

CHEMAN DES MAZOLS 2, CH-1700 FRIBOURG, SWITZERLAND

Inventors:

#	Inventor's Name	Inventor's Address
1	AUBEE, NORMAN, DORIEN, JOSEPH	32 CUMSRRN DRIVE, OKOTOKS, ALBERTA, T1S 1S8,CANADA
2	BROWN, STEPHEN , JOHN	157 SPARROWHAWK PLACE SE, CALGARY, ALBERTA, T2Z 2G7 CANADA
3	DIBBIN, CHRISTOPHER, JOHN, BROOKE	187 ROCKY RIDGE LANDING NW, CALGARY, ALBERTA, T3G 4J7, CANADA
4	ELSTON, CLAYTON, TREVOR	1112 JOHNSON STREET, KINGSTON, ONTARIO, K7M 2N5, CANADA
5	ARNOULD, GILBERT, ALEXANDER	117 HAMPTON CLOSE NW, CALGARY7, ALBERTA, T3A 6B6, CANADA
6	MARSHALL, SARAH	317-5 AVEMIE ME, CALGARY, ALBERTA, T2E OK9,
7	KALE, LWRENCE, THOMAS	815 BOULDER DRIVE, BETHEL PARK, PENNSYLVANIA 15102, U.S.A
8	WEBER, MARK	6320 THOMBY WAY NW, CALGARY, ALBERTA, T2K 5K9, CANADA

PCT International Classification Number

C08J 5/18

PCT International Application Number

PCT/CA2003/001585

PCT International Filing date

2003-10-20

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2,411,183	2002-11-05	Canada