Title of Invention

"A SYNERGISTIC ANTIBLOCKING COMPOSITION"

Abstract This invention concerns a mixture of a first component Selected from talcs and a second component selected from feldspars, nephelines and neplleliue syenites, wherein the ratio of the first component to the second component provides an enhanced abraaiveness property. The invention further relates to an antiblock agent made from such mixture. This mixture provides favorable optical properties when used in a polyolefin film, This invention also relates tapolyolcfm resin composition having the mixture therein, as well as to films made with such.
Full Text FIELD OF INVENTION
This invention relates to a synergistic antiblocking composition comprising a first component selected from talcs along with second component selected from a group consisting of feldspar and nepheline syenites.
More particularly, the invention relates to the use of a combination of talc and feldspar, nepheline and/or nepheline syenite.
BACK GROUND
The invention pertains in polyolefin resin compositions that are designed to produce clear films that have satisfactory antiblocking capability and where the antiblocking agent exhibits low abrasivity. These films would be used in a broad range of packaging and covering films applications.
Polyolefin films are used extensively for packing around the world and, increasingly, are replacing traditional materials such as paper. High clarity polyolefin films allow easy viewing and identification of the package contents. When plastic film is produced, however, there is a tendency for two or more contacting layers of the films to stick together, or "block", making separation of the film, opening the bag, or finding the end of the roll difficult.
Addition of inorganic mineral fillers to polyolefin film to reduce blocking is required commercially. It is well recognized that films produced from resin containing antiblock fillers have a rougher surface, which reduces the intimate contact between layers of film and reduces blocking, hence, the term "antiblocking agent" is applied to such fillers.
Not all inorganic fillers are effective antiblocks and some effective antiblocks have other problems (such as high cost, high abrasivity, adverse affect on opticals, health hazard) which limit their commercial utility. The objective is to add as little antiblock as possible to reduce blocking force to the required level, while minimizing the adverse effects on optical properties of the film and other concerns such as wear on processing equipment.
Diatomaceous earth has been widely used as a moderately effective

antiblocking agent but has the following adverse attributes: fair film haze, poor film clarity, very high abrasiveness, and is modeiatcly expensive. Talc is also widely used in certain, polyolefin formulations as a moderately effective antiblocking agent. Its advantages over diatomaceous earth ace lower cost, excelled film clarity, aadi very low abrasiveness. However, its film haze is usually only fair and would not be suitable for high clarity packaging applications. While nepheline syenite or felspar have been considered as antiblocking agents for high clarity film applications (because their optical index of refraction, is closer to that of polyethylene), they are relatively ineffective in reducing blocking forces, and have very high abrasiveness
Abrasivity of inorganic antiblocks is of concern for Several reasons. Highly abrasive antiblocks will contribute to rapid equipment wear in compounding and processing equipment. When wear reaches the point where it chariges the equipment dimensions in critical areas, both dispersion of additives in the resfa, and output rates can be adversely affected. In such cases, product quality may surfer and production costs may increase, particularly if the equipment must be taken out of service and new parts purchased to replace worn pieces of equipment. In addition; abrasion of equipment will introduce metal contamination into the plastic product, 'which may have a detrimental effect on product stability or color or both. Antiblocks with low abrasiveness are preferred for these reasons,
There have been many attempts by others to solvg the problem of balancing polyolefin film antiblocking and haze properties but nene have addressed the additional concerns of film clarity and the antiblock abrasivity and cost (which are all necessary considerations for a viable commercial product). The existing situation is that a cost effective antiblocking formulation for high clarity polyalefin films with low abrasivity of the antiblock has not yet been found.
SUMMARY OF THE INVENTION
The present invention concerns a mixture of a first component selected from talcs and a second component selected from feldspars, nephelincs and nepheljne syenites, wherein the ratio of the first component to the second component provides an abrasiveness property significantly less than that expected from the law of mixtures. The invention further relates to m antiblock agent comprising a mixture of a first component selected from talcs and a second component selected from feldspars,

nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an antiblocking action significantly greater than eithet component alone. This agent does not result in a significant loss of optical properties when used in a polyolefin film.
This invention .also relates to a mixture of a first component selected from talcs and a second component selected from feldspars, nepheliffe and nepheline syenites, wherein title ratio of the first component to the second component provides an abrasiveness property significantly less than that expected from the law of mixtures and wherein the ratio of the first component to the second component pf provides an antiblocking action significantly greater than either component alone,
This invention also relates to a polyolefin resin composition wherein the ratio of the first component to the second component further provides an antiblocking action significantly greater than either component alone, and the abfasiveness property of the first and-second component in mixture is about eighty percerit or less than that expected from the law of mixtures.
Also this invention relates to a polyolefin film comprising the polyolefin resin composition, and such film can be made from the above components having an abrasiveness property significantly less than that expected from the law of mixtures, and the film can have an antiblocking action significantly greater than when made from either component alone.
An advantage of the present invention is that the mixtures and polyolefin resin compositions can be used to produce films that have satisfactory antiblocking and optical properties (haziness and clarity)- The precursor mixture alfcb can have low abrasivity. The combination produces a synergistic effect wherein the degree of antiblocking action is unexpectedly higher than either alone, whil^ still retaining optical properties and having low abrasivity.
Statement of Invention:
A synergistic antiblocking composition comprising a first component selected from talcs along with a second componsnt selected from a group consisting of feldspar and nepheline syenites, having low abrasiveness, wherein the ratio of first component and second component is in the range of 1:3 to 3:1.
Related Art:
In Monsanto et al, "Method for the production of Antifog Polyolefin Film" Japanese Kokai No, 60 (1985)-49,047, there is disclosed a method of using polyolefm resin composition containing polyolefm resin, two types of finely powdered inorganic filler, an unsaturated fatty acid amide and a mixed fatty acid polyolester.
In hayashida et al, Polyolefin resin composition", US patent Number
5,346,944 there is disclosed! a polyol'efin resin composition having fin antiblocking agent and, optionally, an antistatic-agent, an ontifogeiiig agent and;Shtioxidants. DESCRIPTION OF EMBODIMENTS OF THE INVENTION
Ohe embodiment of the present invention is a mixture of a first component selected from, tales and a second component selected! from feldspars, nephelines and ixepheline syenites, wherein the ratio of the first component to the second component provides an abrasiveriess property significantly less than that expected from the law of mixtures.
Preferably the abrasiveness property is about eighty percent or less than that expected from the law of mixtures, more preferably is about fifty percent or less than that expected from the law of mixtures,
•. . ' This mixture has use as a precursor material useabte in polyolefm resin compositions and in films and other types of products, such as sheets, molds andi castables, manufactured from such polyolefin resin, compositions. Polyolefms considered suitable for the present invention may be any polyolefin which can be clear, crystalline, and capable of forming a self-supported film, Non-limiting examples include crystalline homopolymers of a-olefin with carbon numbers ranging from 2 to 12 or a blend; of two or more crystalline copolymers or ethyleiu^Vinlyacetata copolymers with others resins, Also, the polyolefm resin can bH a high-density polyethylene, low density polyethylene, linear low-density polyethylene, polypropylene, cthylctxe-propylene eopolymers, p61y-l-butene, ethyiene-vinyl adetate copolymers., etc., and low and medium-density polyethylenes. Additional examples are represented by random or block copolymers of polyethylene, polypropylene pdiy-r-metiiylpentene-1, and ethylone-propylene, and ethylene^-roprylene-hexane copolyraers. Among them, copolymers of ethylcne and propylene and those containing 1 or 2 selected from butene-1, hexane-1, 4-methylpentene-l, and octene-1 (the so-called LLDPE) are particularly suitable, The method of producing polyolefm resin used in the present invention is not limited. For example, it can be manufactured by ionic polymerization or radical polymerization, Examples of polyolefm resins obtained by ionic polymerization include homopolymers such as polyethylene, polypropylene, poly-butane-1, and poly-4-melhylpcntene and ethylene copolymers obtained by copolymerizing ethylene and a-olefin, a-olefins having from 3 to 18 carbon atoms such as propylene,
butene-1, 4-methylpeatene-l, hexens-1, octene-1, deeene-1, and octadecene-1 are used as a-olefins, These a-olefins can be used individually or as two pi .mote types. .Other examples include propylene copolymers such as copolymers of propyiene and butene-1. Examples of polyolefin resins obtained by radical polymerization Include ethylene alone or ethylene copolymers obtained by copolymerteing ethylene and radical polymerizable monomers. Examples of radical polymerizable monomers include unsaturated cafboxylic acids such as acrylic acid, methylaorylic acid and maleie acid esters and acid anhydrides thereof, and vinyl esters such as vinyl acetate. Concrete examples of esters of unsaturated earboxylic acids include atiiyl acrylate, methyl methacrylate and glycidly
f
methacrylate. These radical polymerizable monomers can be used individually or as two or more types.
•The talc in the present invention is selected ftom thf>se talcs useable for manufactured polyolefin materials. A typical talc is inonoclinic ir* crystal structure, has a specific gravity of about 2,6 to 2.8 and an empirical formula of Mg3 Si, O10(OH)a.
Preferably, the average particle size of the tale used is from about 0.1 microns to about 10 microns.
The second component is selected from feldspars, hephellnes and nepheiine syenites, or mixtures thereof. Such materials arc known to those in the art and are conveniently defined in "Minerals and Rocks", The "New.Encyclopedic Britannioa. Vol. 24, pp. 151-157, 175-179, Encyclopedia Britarthica, Inc. (Chicago, 1986), incorporated herein by reference in its entirety.
Preferably the average particle size of the second component used is from about 0.1 micron to about 10 microns.
The mixture is made by any convenient mixing operation which does not adversely reduce or agglomerate the component Such mixing can be, but is not required to be, integrated into the milling operation, if any, of the components,
The abrasiveness property can be determined by Using the Einlehner AT 1000 Abrasion Tester and the recommend methodology of the manufacturer, as such equipment and methods are known in the art. Incorporated herein by reference in its entirety is the manual "Einlehner Abrasion Tester AT 1000".
In another embodiment, the present invention is an antiblock agent comprising a mixture of a first component selected from talcs and a second component

selected from feldspars, nephelines and nepheline syenites, waerein the ratio of the first component to the second component provides an antiblocking actioa significantly greater than either component alone.
In a preferred embodiment, the ratio'of the two components is from about 1/3 to about 3/1; that is, about 25 percent to about 75 percent of tele with the balance being the second component. More preferably, the ratio Is from, about 45/55 to about 75/15.
Preferably, the antiblocking action produces a blocking degree of about eight-five percent or less than either component alone; more preferably a blocking degree of about seventy-five percent or less than either component alone; and even more preferably a blocking degree of about fifty percent or less man either component alone.
The antiblock agent can be used to produce a polyolefin film and when so used, preferably the mixture of the first component and the second component does not result in a significant loss of optical properties such as clarity and haze.
In another embodiment, the invention is a mixture of a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an abrasiveness property significantly less than that expected from the law of mixtures and wherein the ratio of the first component to the second component provides an antiblocking action significantly greater than either component alone.
Preferably, the ratio of the first and second component ranges from about 1/3 to 3/1 and the abrasiveness property of the first and second component in mixture is about fifty percent or less than that expected from the law of mixtures and the antiblocking agent produces a blocking degree of about fifty percent or less.
The mixture of the first and second component can be produced as a precursor mixture added into a polyolefm resin composition or formulated in situ in either a polyelefin resin composition or as a portion of the polyolefm film production, The order of addition of the separate components is not critical. When formulated in situ, the components can be added separately in sequence or simultaneously or into separate master batches to be later blended together,
In yet another embodiment, the invention is a polyolefin resin
omposition having a mixture of a first component selected from talcs and a second component selected from), feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an abrasiveness property significantly less than that expected from the law of mixtures.
Another embodiment is a polyolefin' film comprising the polyolefm resin composition having a ratio of the first component to the second component which provides an abrasiveness property significantly less than that expected from the law of mixtures and further provides an antiblocking action significantly greater than either component alone,
Preferably, the polyolefin resin composition has a mixture of the first and second component wherein the ratio of the first component io second component is from about 1/3 to 3/1 and the abrasiveness property of the first and second component in mixture is about eighty percent or less than that expected from the law of mixtures and the first and second component in combination produces a blocking degree of about fifty percent or legs.
In another embodiment, the invention is a polyolefin film comprising a first component selected from talcs and a second component selected from feldspars, nephelines and nepheline syenites, wherein the ratio of the first component to the second component provides an abrasiveness property significantly less than that expected from the law of mixtures.
Preferably, the polyolefm film comprising a first component selected from talcs and a second component selected from feldspars, naphelines and nepheline syenites, wherein the ratio of the first component to the second" component provides an abrasiveness property significantly less than that expected front the law of mixtures and wherein the ratio of the first component to the second component provides an antiblocking action significantly greater than either component alone,
The present invention is described in the following illustrative examples which are not intended to limit the scope of the invention.
EXAMPLES Example 1
Laboratory abrasiveness measurements of antiblock agents were conducted using an Einlehner Abrasion Tester. Mineral and combinations thereof were

tested for abrasiveness compared to diatomaceous earth as a control. Samples of Talc
A (PolyTaic AG609), Talc B (Polybloc), nepheline syenite (Minex 75. and
diatomaceous earth (Super Floss) were tested, Samples and blends are described as
follows:
Test 1 = 50/50* Blend of Talc A and Nepheline syenite
Test 2 = 50/50 Blend of Talc B and Nepheline syenite
Test 3 = 75/25 Blend of Talc A and Nepheline syenite
Test 4 « 25/75 Blend of Talc A and Nepheline syenite
Test 5 - 100% Talc A
Test 6 - 100% Nepheline syenite
Test 7 - 100% diatomaceous earth
*"50/50" means 50 weight percent to 50 weight percent.
All samples were tested on the Einlehner Model AT-1000 Tester as 10% dry minerals solids slurries, The wear body was a bronze wire screen. Test duration was 100 minutes and/or 174,000 abrasion cycles. The test results represents the weight loss of the wire expressed in milligrams (mgs). Results are provided in Table 1.
Table 1
(Table Removed)Example 2
In this experiment, talc and nepheline syenite minerals, alone and in
combinations, along with diatomaeeous earth as a control were compounded into LDPE (low density polyethylene) resin using a Leistritz twin screw extruded at a total loading of 50% to produce antiblock master batches. The ratio of talc to nepbeline syenite was varied from 0/100 to 100/0. The master batches were then let down (mixed) with LDPE and an erucamide slip masterbateh and blown into one millimeter thick film using a single screw blown film line so as to yield a final film formulation of 2000 ppm (parts pet million) total mineral antiblock and 750 ppm erucarnide slip agent. The film products were then tested for blocking degree and optical properties (haze and clarity) using the following procedures. Test Procedures:
(1) Blocking Degree.
The parallel plate method of ASTM D3354-74 was used to measure degree of blocking, In preparing the samples, 8" x 8" pieces wer0 cut from the layflat tubing. The double film layer was separated, passed slowly over ft grounded bar to remove static charges, and then reunited so that the inside surfaced of the original bubble were in contact with each other, All films were conditioned under a top load of 1.0 psi for 24 hours using a recirculating forced air oven set a 40SC. The force required to separate these two layers was then determined and expressed as grams.
(2) Haze
This test was conducted according to ASTM D 1003. Haze is the pctcentage of transmitted light which in passing through the film specimen, is scattered. The lower the haze number, the better the light-tnuismitting film optical property.
(3) Clarity
A Zebedee CL-100 clarity meter was used for this test and operated in accordance with the manufacturers procedure. Optical clarity is defined as the distinctness of detail that an object can be seen through a film. The higher the clarity number, the better the object resolution of the film.
Specific antiblocking minerals used for these samples were: Talo A (PolyTalc AG609), Talc B (Polybloc), nepheline syenite (Minex 7), and diatomaeeous earth (Super Floss). Results of blocking degree, haze and clarity for the samples of Example 2 are in Table 2.
Table
Formulation; 5500 ppm Antiblock and No Slip in LDPE Filhi

(Table Removed)Talc C is AST 2500 Talc.



We Claim:
1. A synergistic antiblocking composition comprising a first component selected
from talcs along with a second component selected from a group consisting of
feldspar and nepheline syenites, having low abrasiveness, wherein the ratio of
first component and second component is in the range of 1:3 to 3:1.
2. The synergistic antiblocking composition as claimed in claim 1, wherein the
ratio of first component and second component is preferably in the range of
45:55 to 3:1.
3. The synergistic antiblocking composition as claimed in claim 1, wherein the
antiblocking property of the said synergistic antiblocking composition is
greater than either component individually.
4. The synergistic antiblocking composition as claimed in claim 1, wherein the
synergistic antiblocking composition produces blocking degree of about
seventy five percent or less than either component.
5. The synergistic antiblocking composition such as herein described in any of
the examples.

Documents:

994-del-1997-abstract.pdf

994-del-1997-assigment.pdf

994-del-1997-claims.pdf

994-DEL-1997-Correspondence Others-(24-03-2011).pdf

994-del-1997-correspondence-others.pdf

994-del-1997-correspondence-po.pdf

994-del-1997-description (complete).pdf

994-del-1997-form-1.pdf

994-del-1997-form-13.pdf

994-del-1997-form-19.pdf

994-del-1997-form-2.pdf

994-del-1997-form-26.pdf

994-DEL-1997-Form-27-(24-03-2011).pdf

994-del-1997-form-3.pdf

994-del-1997-form-4.pdf

994-del-1997-form-6.pdf

994-del-1997-gpa.pdf

994-del-1997-petition-others.pdf


Patent Number 215306
Indian Patent Application Number 994/DEL/1997
PG Journal Number 11/2008
Publication Date 14-Mar-2008
Grant Date 25-Feb-2008
Date of Filing 17-Apr-1997
Name of Patentee MINERALS TECHNOLOGIES INC.
Applicant Address 405 LAXINGTON AVENUE, NEW YORK, NEW YORK 10174-1901, U.S.A.
Inventors:
# Inventor's Name Inventor's Address
1 JOSEPH ANTHONY RADOSTA 3 WEDGEWOOD DRIVE, EASTON, PA, 18045, U.S.A.
PCT International Classification Number C08K 003/34
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 08/636,364 1996-04-23 U.S.A.