Title of Invention

A PROPYLENE POLYMER COMPOSITION

Abstract This invention relates to a propylene polymer composition comprising propylene random copolymer and propylene homopolymer; wherein the propylene random copolymer is a copolymer of propylene and ethylene, optionally comprising one or more alpha-olefins of C4-C10; the propylene polymer composition has an overall isotacticity index, as determined by nuclear magnetic resonance method, of greater than or equal to 96.5%, and an ethylene content of 0.3 wt% to 0.8 wt%.
Full Text IEC050045
Propylene polymer composition and oriented film prepared thereby
Cross-reference of the related applications
This application is based upon and claims priority of Chinese Patent
Application No. 200510004901.9 filed on Jan. 28, 2005, the contents being
incorporated herein for reference in their entirety for all purposes.
Technical field
The present invention relates to a propylene polymer composition, in particular,
to a propylene polymer composition for producing a biaxially oriented film and a
method for preparing the same, and to a biaxially oriented polypropylene film
(BOPP) prepared by the composition.
Background art
Owing to its excellent optical properties, mechanical properties and packaging
adaptability, polypropylene film has been widely applied to the field of packaging
material. In particular, biaxially oriented polypropylene film (BOPP) has been
widely applied to package various products such as foods, medicines, commodities
and cigarettes and also applied as a substrate material for high-strength composite
film, due to its features of softness, good transparency, non-toxicity, good water
repellent property and high mechanical strength.
Biaxially oriented polypropylene film (BOPP) is generally produced with
polypropylene resin as raw material by the steps of: extruding the resin to obtain a
film, and then subjecting the film to biaxial stretching, heat treatment and cooling
treatment. To meet the requirement of high-speed film production in a large scale,
the polypropylene resin raw material should have both good tensile strength and
excellent high-temperature stretching property. As far as polypropylene is
concerned, it is generally deemed that a lower isotacticity index and a lower

melting temperature of the polymer are favorable to the processing and forming of
the BOPP film, but the mechanical properties such as tensile strength and stiffness
of the film as obtained will be reduced. Thus, a method of adding C5-C9 petroleum
resin to isotactic polypropylene material was developed in order to increase
modulus of the material, thereby improving the stiffness of the finally obtained
polypropylene film. For instance, Chinese Patent CN1102419A disclosed a
propylene polymer composition comprising C5 hydrocarbons free of polar group,
the use of which can improve the steam barrier property, transparency and Young's
modulus of the polypropylene oriented film obtained thereby. However, this
method not only needs extra components thereby increasing the production cost,
but also does not have a satisfactory result.
In the prior art, the methods for preparing BOPP films with propylene random
copolymers, in particular, compositions comprising propylene random copolymers,
as raw materials are also disclosed, wherein the random copolymers are generally
copolymers of propylene and alpha-olefins such as ethylene. For instance, as
disclosed in Chinese Patent CN1404500A, the amount of ethylene in propylene
copolymer or in propylene polymer composition should be greater than 0.8 wt%,
generally in the range of 0.8-1.5 wt%. Moreover, the MFR value of the first
polypropylene (generally a homopolymer) is lower than that of the second
propylene random copolymer, i.e., the molecular weight of the first polypropylene
(generally a homopolymer) is higher than that of the second propylene random
copolymer, and the difference in the MFR values being preferably greater than 5
g/10 min. Such control in ethylene content and melt flow rate in the propylene
polymer composition might be applicable to the special polymerization reactor and
special polymerization method, wherein two interconnected gaseous
polymerization reaction zones are used, as adopted in the embodiment of that
patent application. However, as to a common reactor or polymerization method,
such control cannot balance the requirement of producing BOPP film and the
achievement of polypropylene resin having satisfactory inherent properties, which

mainly concern high soluble content of the polypropylene resin and reduced,
transparency and stiffness of the film.
In view of the situations in the prior art, it is desired to develop a propylene
polymer composition for producing a biaxially oriented film, which can better
balance the high-temperature stretching properties and physical properties of the
film, thereby obtaining a BOPP film having excellent comprehensive properties.
The present inventors discovered by laborious experiments that by increasing
the isotacticity of the polymer having a relatively higher MFR value (i.e., a
relatively lower molecular weight) in the propylene polymer composition to keep
the overall isotacticity of the propylene polymer composition at a relatively higher
level, a polypropylene oriented film having high modulus, with its other properties
such as transparency and mechanical properties being somewhat improved, can be
obtained, without the addition of any stiffening agent (such as C5-C9 petroleum
resin)
Contents of the invention
The present invention provides a propylene polymer composition for
producing a biaxially oriented film, comprising propylene random copolymer and
propylene homopolymer; wherein the propylene random copolymer is a copolymer
of propylene and ethylene, optionally comprising one or more alpha-olefins of
C4-C10. The propylene polymer composition has an overall isotacticity index, as
determined by nuclear magnetic resonance (NMR) method, of greater than or equal
to 96.5%, and an ethylene content of greater than 0.3 wt%.
To obtain a BOPP film having high stiffness (including high transverse Young
modulus and longitudinal Young modulus), it is very important to provide a
propylene homopolymer having a relatively higher isotacticity index. In principle,
the higher, the better. In comparison with the prior art, the present invention differs
in that: under the condition of maintaining a suitable range of ethylene content in
the composition, the overall isotacticity index of the composition is controlled at a

relatively higher level (being completely higher than that in the prior art) by
increasing the isotacticity index of propylene homopolymer, thereby achieving the
object of increasing the stiffness of the film.
In the present invention, the overall isotacticity index of the final propylene
polymer composition is determined by NMR method, wherein the ethylene
segments are regarded as defects. The formula for calculation is as follows:

wherein, Toverall represents the overall isotacticity index of the propylene
polymer composition, [mm], [mr], [rr], [PPE] and [EPE] are molar contents of the
corresponding triads (characterized by the corresponding peak areas after
normalization).
A BOPP film having excellent properties can be obtained when the overall
isotacticity index is greater than or equal to 96.5%, preferably greater than or equal
to 97%, more preferably greater than or equal to 97.5%. In contrast, the propylene
copolymer resin useful for producing BOPP film, as disclosed in the prior art,
generally has an overall isotacticity index of less than 96%.
The crystallization distribution curve of the propylene polymer composition
described herein is determined by CRYSTAF method (described in detail
hereinafter) to obtain a Dispersion index R, wherein R = (Tw/Tn - 1) x 100, wherein
Tw and Tn respectively represent weight-average and number-average
crystallization temperatures calculated by CRYSTAF method. In the present
invention, R is preferably less than or equal to 2.5, more preferably less than or
equal to 2.0. In contrast, the R values of products known in the field are generally
greater than 2.5.
Other properties of the present propylene polymer composition for
producing the BOPP film are preferably as follows.
In the propylene polymer composition, the content of fraction soluble in
xylene at room temperature (about 25°C) is preferably less than 3 wt%, more

preferably lower than 2.6 wt%, in particular preferably lower than or equal to 2.0
wt%. In general, the higher the content of fraction soluble in xylene is, the lower
rigidity the film will have, and which higher content possibly causes that the film
cannot contact directly with food, medicine and the like as a packaging material, or
the article to be packaged may be polluted.
In order to obtain a BOPP film having excellent comprehensive properties
and good processability, it is also very important to control the molecular weight
and molecular weight distribution of the propylene polymer composition. Herein, it
is preferred that, in the propylene polymer composition, the MFR value of the
propylene random copolymer is controlled to be lower than that of the propylene
homopolymer, i.e., the molecular weight of the propylene random copolymer is
greater than that of the propylene homopolymer. The MFR value is determined
under a load of 2.16 kg at 230°C according to the method of ISO 1133. Preferably,
the propylene random copolymer has a MFR value of 0.05-0.5 g/10 min, and the
finally obtained propylene polymer composition has a MFR value of 1-8 g/10 min.
More preferably, the propylene random copolymer has a MFR value of 0.1-0.3 g/10
min, and the finally obtained propylene polymer composition has a MFR value of
2-4 g/10 min. The propylene polymer composition has a molecular weight
distribution index (weight-average molecular weight/numeric-average molecular
weight) of 4-10, preferably 5-7.
For satisfying the above requirements about molecular weight and molecular
weight distribution, the mass ratio of propylene random copolymer and propylene
homopolymer in the propylene polymer composition is generally 30:70 to 70:30,
preferably 65:35 to 35:65, more preferably 55:45 to 45:55.
In one specific embodiment herein, it is usual to control the comomoner
ethylene content of the propylene random copolymer in the propylene polymer
composition, thereby making the ethylene content in the finally obtained propylene
polymer composition to be greater than 0.3 wt%, preferably 0.3-0.8 wt%. Moreover,
the propylene random copolymer further optionally comprises one or more

alpha-olefins of C4-C10, said alpha-olefins of C4-C10 specifically including 1-butene,
1-pentene, 1-hexene, 4-methyl-1-pentene and 1-octene, preferably 1-butene.
In one preferred embodiment described herein, the propylene polymer
composition is characterized by having:
(1) an overall isotacticity index, as determined by NMR method, of greater
than or equal to 97%;
(2) an ethylene content of 0.3-0.8 wt%;
(3) a Dispersion index R of less than or equal to 2.0 according to the;,
crystallization distribution curve as determined by a CRYSTAF, model 200;
(4) a content of fraction soluble in xylene at room temperature (about 25 °C)
less than 2.6 wt%; and
(5) a MFR value of 1-3 g/10 min, wherein the propylene random copolymer
having a MFR value of 0.1 -0.3 g/10 min.
The propylene polymer composition for producing biaxially oriented film in
the present invention may be prepared by one or more polymerization steps.
Preferably, it is prepared, in the presence of a Ziegler-Natta catalyst having high
activity and high stereo-selectivity, by a method comprising two-step
polymerization reactions, wherein one of the steps comprises copolymerizing
propylene with ethylene and optionally one or more alpha-olefins of C4-C10 to
obtain a propylene random copolymer, and the other step comprises
homopolymerizing propylene to obtain a propylene homopolymer. The two-step
polymerization reactions may be stepwise carried out in different or same reaction
zone(s). However, the two-step polymerization reactions are in an arbitrary order.
The polymerization reactions as above described may be carried out in
propylene liquid phase, or gas phase, or by using a liquid-gas combined process. In
liquid phase polymerization, the polymerization temperature is 0-150°C, preferably
40-100°C; and the polymerization pressure is higher than the saturated vapor
pressure of propylene under the polymerization temperature. In gas phase
polymerization, the polymerization temperature is 0-150°C, preferably 40-100°C;

and the polymerization pressure is normal pressure or higher, preferably 1.0-3.0
MPa (gauge pressure, the same below). The polymerization may be carried out
continuously or intermittently. The continuous polymerization may be carried out
by using two or more loop reactors_in series, or two or more kettle-type reactors in
series, or two or more gas phase reactors in series; or the combinations of loop
reactor, kettle-type reactor and gas phase reactor. As to continuous liquid phase
polymerization, the catalyst generally needs to undergo continuous or intermittent
prepolymerization. By prepolymerizing with propylene, the catalyst can effectively
control the particle shape of polymer during reaction, and reduce the rupture of
polymer particles; and also the polymerization activity of the catalyst can be
brought into full effect. The prepolymerization reaction is generally carried out
under relatively milder conditions, preferably the polymerization temperature is
lower than 30°C, and the prepolymerization multiple is controlled within 3-1,000
times. In continuous gas phase polymerization, the catalyst may be either
prepolymerized or not.
Whether in the homopolymerization or coplymerization of propylene, a
molecular weight regulator is used for regulating the molecular weight of polymer,
so that the MFR of propylene random copolymer is lower than that of propylene
homopolymer. The molecular weight regulator is preferably hydrogen.
The polymerization reactions as above described are preferably carried out in
the presence of a Ziegler-Natta catalyst having high stereo-selectivity. The
"Ziegler-Natta catalyst having high stereo-selectivity" used herein refers to the
catalyst capable of preparing a propylene homopolymer having isotacticity index of
greater than 97%, preferably greater than 98%, more preferably greater than 99%.
This type of catalyst generally comprises active solid catalyst component,
preferably a Ti-containing solid catalyst as an active component and an organic
aluminum compound as a co-catalyst component, to which an external electron
donor component may be optionally added.
The concrete examples for this type of catalyst are disclosed in Chinese

Patents: CN85100997A, CN1258680A, CN1258683A, CN1258684A,'
CN1091748A, CN1330086A, CN1298887A, CN1298888A and CN1436796A.
These catalysts may be directly used or prepolymerized prior to use. The catalysts
as disclosed in Chinese Patents: CN1330086A, CN85100997 and CN1258683A
are particularly favorable for use in the present invention.
The Ti-containing active solid catalyst component may be prepared according
to various methods.
Usually, the catalyst active component is prepared by loading a Ti compound
and an internal electron donor compound on a MgCl2.nROH adduct, wherein the
MgCl2.nROH adduct is an adduct of MgCl2 and alcohol, preferably in the form of
spherical particles; and wherein n is usually 2.0 to 3.5, R is an alkyl group having 1
to 4 carbon atoms, and the alcohol includes ethanol, propanol, isopropanol, butanol,
isobutanol, isooctanol and etc. For the concrete preparation steps, one may refer to
Chinese Patents CN1036011C and CN1330086A.
Additionally, the Ti-containing solid catalyst component may also be prepared
by referring to the following method as disclosed in Chinese Patents CN85100997
and CN1258683A:
Firstly, magnesium halide is dissolved with a solvent system consisting of an
organic epoxide, an organic phosphorus compound and an inert diluent to obtain a
homogenous solution; the solution is mixed with a Ti compound, and then a solid is
precipitated in the presence of an auxiliary precipitation; the solid is treated with an
internal electron donor compound thereby loading it on the solid, if necessary, the
solid is further treated with titanium tetrahalide and an inert diluent, thereby
obtaining the Ti-containing solid catalyst component; wherein the auxiliary
precipitation is one selected from organic anhydride, organic acid, ether and ketone.
Wherein, the amounts of various components are, based on per mole of magnesium
halide, as follows: the organic epoxide 0.2-10 mol, the organic phosphorus
compound 0.1-3 mol, the auxiliary precipitation 0.03-1.0 mol, the titanium
compound 0.5-150 mol, and the internal electron donor compound 0.01-5 mol,

preferably 0.05-1 mol.
The internal electron donor compound in the catalyst component is usually
selected from aliphatic dicarboxylic acid esters or aromatic dicarboxylic acid esters,
preferably, dialkyl phthalates, for example, e.g., diethyl phthalate, diisobutyl
phthalate, di-n-butyl phthalate, diisooctyl phthalate, di-n-octyl phthalate, and etc.
The internal electron donor compound can also be selected from a dihydric
alcohol ester compound shown as in formula (I):
wherein, R1-R6 and R1-R2n radicals, which are same or different, represent
hydrogen, halogen, or substituted or unsubstituted linear or branched C1-C20 alkyl
group, C3-C20 cycloalkyl group, C6-C20 aryl group, C7-C20 alkaryl, C7-C20 aralkyl,
C2-C10 alkenyl, C10-C20 fused ring aryl or C2-C10 ester group; but with the proviso
that R1 and R2 are not hydrogen; R3-R6 and R1 -R2n radicals optionally contain one
or more heteroatoms to substitute carbon or hydrogen atom(s) or both of them; said
heteroatom is selected from the group consisting of nitrogen, oxygen, sulfur, silicon,
phosphorus or halo atom; optionally, one or more R3-R6 and R1 -R2n radicals are
linked together to form a ring; n is an integer of 0 to 10.
This type of dihydric alcohol ester compound is disclosed in Chinese Patents
CN1436766A, CN1436796Aand CN1453298A.
The organic aluminum compound as a co-catalyst component preferably
includes alkyl aluminum compound, more preferably trialkylaluminum such as
triethylaluminum, triisobutylaluminum and tri-b-butyl aluminum. In the catalyst,
the molar ratio of Ti/Al is 1:25-100.
In order to increase the overall isotacticity index of the final polymer
composition, in particular the isotacticity index of propylene homopolymer in the
composition, it is usually desired to introduce an external electron donor compound

to the catalyst. The external electron donor compound is preferably an organic
silicon compound having a formula RnSi(OR')4-n, wherein 0 which are same or different, represent alkyl group, cycloalkyl group, aryl group,
haloalkyl group and etc.; R may also be halo or hydrogen atom. Specifically, the
external electron donor compound includes trimethylmethoxysilane,
trimethylethoxysilane, trimethylphenoxysilane, dimethyldimethoxysilane,
dimethyldiethoxysilane, methyl tert-butyldimethoxysilane,
methylisopropyldimethoxysilane, diphenoxydimethoxysilane,
diphenyldiethyoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane,
vinyltrimethoxysilane, cyclohexylmethyldimethoxysilane,
dicyclopentyldimethoxysilane, diisopropyldimethoxysilane,
diisobutyldimethoxysilane, 2-ethylpiperidyl-2-tert-butyldimethoxysilane,
(1,1,1 -trifluoro-2-propyl)-2-ethylpiperidyldimethoxysilane and
(l,l,l-trifluoro-2-propyl)-methyldimethoxysilane and etc., During the
polymerization reactions, the isotacticity index of polypropylene can be effectively
controlled through regulating the ratio between the organic aluminum compound as
a co-catalyst component and the organic silicon compound as an external electron
donor component in the catalyst described herein. In order to obtain a propylene
polymer composition having the desired properties, the ratio of said two
components, based on the molar ratio of Al/Si, is preferably 4-30, more preferably
6-20.
In one preferred embodiment, the method for preparing the propylene polymer
composition described herein comprises subjecting propylene to continuous or
intermittent random copolymerization and homopolymerization reactions in two or
more reaction zones in series; wherein, a molecular weight regulator such as
hydrogen is added in different amounts to different reaction zones, so that the MFR
of propylene copolymer is lower than that of propylene homopolymer; and wherein,
the yield ratio of the copolymerization and homopolymerization of propylene is
30:70 to 70:30, the polymerization temperature is controlled in the range of

60-80°C, and the polymerization reactions are carried out in liquid phase.
Wherein, a specific embodiment includes subjecting propylene to continuous
random copolymerization and homopolymerization reactions in two loop reactors
in series. Wherein, in the presence of a Ziegler-Natta catalyst having high
stereo-selectivity, the random copolymerization reaction of propylene and ethylene
is carried out in the first loop reactor for a certain time, thereafter the reactants are
transferred to the second loop reactor for carrying out the homopolymerization
reaction of propylene; and wherein, hydrogen is added in different amounts to the
first and second loop reactors, the hydrogen amount in the first loop reactor being
lower than that in the second loop reactor, so that the MFR value of the propylene
copolymer in the first stage is lower than that of the propylene homopolymer in the
second stage. The yield ratio in the first and second loop reactors is about 65:35 to
55:45, the polymerization temperature in the two loop reactors is controlled in the
range of 60-80°C, and the polymerization reactions are liquid phase bulk reactions.
Another specific embodiment comprises subjecting propylene to continuous
random copolymerization and homopolymerization reactions in two kettle-type
reactors in series. Wherein, in the presence of the above Ziegler-Natta catalyst of
high efficiency as result of the prepolymerization, the random copolymerization
reaction of propylene and ethylene is carried out in the first kettle-type reactor for a
certain time, thereafter the reactants are transferred to the second kettle-type reactor
for carrying out the homopolymerization reaction of propylene; and wherein,
hydrogen is added in different amounts to the first and second kettle-type reactors,
with the hydrogen amount in the first kettle-type reactor being lower than that in
the second kettle-type reactor. Alternatively, the homopolymerization reaction of
propylene may be firstly carried out prior to the copolymerization reaction of
propylene and ethylene. No matter which of the steps is firstly carried out, the MFR
value of the propylene copolymer is lower than that of the propylene homopolymer.
The yield ratio of the copolymerization and homopolymerization of propylene is
about 65:35 to 55:45, the polymerization temperature in the two kettle-type reactors

is controlled in the range of 60-80°C, and the polymerization reactions are liquid
phase bulk reactions.
The propylene polymer composition described herein can also be prepared by,
apart from the above multi-step polymerization reactions, mechanical blending in
melt state by using a routine mixing device such as screw extruder.
The propylene polymer composition described herein can be used for
producing single- or multi-layer, uni- or bi-axially oriented film. The multi-layer
oriented film has at least one layer containing the propylene polymer composition
described herein.
The followings are directed in detail to BOPP film produced by the propylene
polymer composition described herein. Prior to producing the BOPP film, the
propylene polymer composition is generally pelletized by extrusion, during which
various additives conventionally used in the field may be added, such as
antioxidants, halogen-absord agents, light stabilizers, heat stabilizers, colorants and
fillers. The antioxidants include phenols, phosphites and etc.; and the
halogen-absord agents include aliphatic metal salts.
The BOPP film described herein can be produced by various well-known
methods, such as flat-film method and tubular-film method. The flat-film method is
often used. The method comprises the steps of: mixing raw materials, extruding,
casting, longitudinally stretching, transversely stretching, edge cutting, treating
with corona, coiling up, ageing, cutting, and packaging.
The BOPP film produced by the propylene polymer composition described
herein exhibits excellent physical properties, which has, in the absence of any
stiffening agent, relatively higher modulus and stiffness, with the transverse Young
modulus being > 5,000 MPa, even > 5,300 Mpa, and the longitudinal Young
modulus being > 2,400 Mpa, even > 2,600 Mpa. The film has a haze of no more
than 0.5%. Owing to the special structure of the propylene polymer composition
described herein, the process for producing the BOPP film is featured with a good
film-forming stability and a film-forming stretching speed of greater than 380

m/min.
All the publications mentioned are incorporated herein for reference in their
entirety for all purposes.
Unless identified otherwise, the percentages, ratios and amounts used herein;
are all on the basis of weight.
Mode of carrying out the invention
The following examples are for illustrative purposes only and are not to be
construed as limiting this invention in any manner.
The methods for determining relevant data of polymers and films in the
present invention and its examples are as follows.
1. The overall isotacticity index and comonomer content of the propylene
polymer composition are determined by the following method.
The overall isotacticity index Toverall and comonomer ethylene (E) content of
the propylene polymer composition described herein are determined by using
AVANCE 400 -nuclear magnetic resonance (NMR) spectrometer by Bruker
company in Germany. The sample is dissolved at 140°C using deuterated
o-dichlorobenzene as solvent, and determined at 125°C using a probe of 10 mm
with a delay time (Dl) of 10 seconds, a sampling time (AT) of 5 seconds, and a
number of scanning of over 5,000 times. The steps of test operation, identification
of spectral peaks and method of data processing are performed according to the test
standard of NMR, and one can refer to the following document for more details: (1)
James C. Randall, A Review of High Resolution Liquid 13Carbon Nuclear Magnetic
Resonance Characterization of Ethylene-Based Polymers, JMS-REV. Macromol.
Chem. Phys., C29 (2&3), 201-317 (1989). (2) Vincenzo Busico, Roberta Cipulo,
Guglielmo Monaco, and Michele Vacatello, Full Assignment of the 13Carbon NMR
Spectra of Regioregular Polypropylenes: Methyl and Methylene Region,
Macromolecules, 30, 6251-6263 (1997).
The formula for calculation of overall isotacticity index is as follows:


2. The determination of Dispersion index (R)—CRYSTAF method
The crystallization distribution curve is determined by using CRYSTAF,
model 200 manufactured by Polymer Characterization S. A. Co., Spain, thereby
obtaining the Dispersion index (R) by using a data processing method "others";
therein. Wherein, 1,2,4-trichlorobenzene is used as solvent (to which
2,6-dibutyl-p-methylphenol as antioxidant is added in a concentration of 0.3 g/1),
the sample amount is 30 mg, the temperature of dissolving sample is set at 160°C,
the rate of lowering temperature is 0.2°C/min, and other operations are performed
according to the specification of the analyzer.
3. The melt flow rate (MFR) is determined under a load of 2.16 kg at 230°C
according to the method described in ISO 1133.
4. The molecular weight distribution is determined by gel permeation
chromatography (GPC), and generally calibrated by a narrow-distributed
polystyrene standard sample.
5. The xylene-soluble is determined according to the method described in
ASTM D5492-98.
6. The melting temperature and crystallization temperature are determined
according to the method described in ASTM D3418-03.
7. The resin tensile strength is determined according to the method described
inASTMD638-00.
8. The resin flexural modulus is determined according to the method described
in ASTMD 790-97.
9. The Izod impact strength is determined according to the method described
in ASTMD 256-00.

10. The Charpy impact strength is determined according to the method
described in GB/T 1043.
11. The haze of film is determined according to the method described in

ASTMD1003-00.
12. The tensile strength and Young modulus of film are determined according
to the method described in GB/T 13022-1991.
13. The heat shrinkage of film is determined according to the method
described in ASTM D1204-02.
Unless identified otherwise, all of the above determinations are conducted
under atmospheric environment.
Example 1
1. Preparation of a catalyst active component
The catalyst active component was prepared according to the method
described in Example 1 of Chinese Patent CN1330086A, comprising Ti 2.4 wt%,
Mg 18.0 wt%, and di-n-butyl phthalate 13 wt%.
2. Preparation of propylene polymer composition
The polymerization reactions were continuously carried out in two loop
reactors in series. Firstly, the above catalyst active component, triethylaluminum as
co-catalyst component and cyclohexylmethyldimethoxysilane as external electron
donor in a mass ratio of 1:10:2 were continuously added to a prepolymerization
reactor, to which adequate liquid propylene was fed for prepolymerization at 15°C
for 6 min. The catalyst as prepolymerized was continuously added to the first loop
reactor, to which propylene, ethylene and hydrogen in a mass ratio of
310000:1100:3 were fed to carry out the random copolymerization reaction of
propylene for 1 h. Thereafter, the reactants were transferred to the second loop
reactor for carrying out the homopolymerization reaction of propylene, to which
fresh propylene and hydrogen in a mass ratio of 1500:1 were supplemented. The
polymerization temperature in the two loop reactors was 70°C, and the yield ratio
in the first and second loop reactors was controlled at 60:40. The properties of the
polymer composition as obtained in the form of powder were shown in Table 1..
Each of the above steps was carried out under a pressure higher than the saturated

vapor pressure of propylene at 70°C, and two liquid phase loop reactors in series
were used therein.
3. Production of BOPP film
0.1 wt% Irgafosl68 additive (antioxidant), 0.2 wt% IrganoxlOlO additive
(antioxidant) and 0.1 wt% calcium stearate (halogen-absord agent) were added to
the polymer powder as above obtained, which was then pelletized with a 65 mm
twin-screw extruder at 220°C.
The materials as pelletized were extruded with a sheet extruder of Φ70 mm at
220°C. By using a flat-film continuous biaxial stretching device, the sheet as
extruded was longitudinally oriented by 10 times at 140°C and then transversely
oriented by 8 times at 170°C, thereby obtaining a A-B-A type biaxially oriented
film having a thickness of about 20 µm, with outside layers and core layer being
the same polymer. The properties of the film were shown in Table 3.
Example 2
1. Preparation of a catalyst active component: the same as that described in
Example 1.
2. Preparation of propylene polymer composition
The reaction conditions were identical with those described in Example 1,
except for that dicyclopentyldimethoxysilane was used as an external electron
donor component, and the yield ratio in the first and second loop reactors was
controlled at 65:35. The properties of the composition as obtained were shown in
Table 1.
3. Production of BOPP film: the same as that described in Example 1. The
properties of the film as obtained were shown in Table 3.
Example 3
1. Preparation of a catalyst active component
The catalyst active component was prepared according to the method

described in Example 1 of Chinese Patent CN85100997, comprising Ti 2.03 wt%,
Mg 17.8 wt%, and diisobutyl phthalate 12 wt%.
2. Preparation of propylene polymer composition: the same as that described
in Example 1. The properties of the composition as obtained were shown in Table.
1.
3. Production of BOPP film: the same as that described in Example 1. The
properties of the film as obtained were shown in Table 3.
Example 4
1. Preparation of a catalyst active component: the same as that described in
Example 3.
2. Preparation of propylene polymer composition: the same as that described
in Example 2. The properties of the composition as obtained were shown in Table
1.
3. Production of BOPP film: the same as that described in Example 1. The
properties of the film as obtained were shown in Table 3.
Comparative Example 1
The polymer used was a high-quality propylene homopolymer FS3011
(Chisso Co, Japan) for producing high-stiffness BOPP film, available in our
country's market. A polypropylene biaxially oriented film was produced with a
flat-film continuous biaxial stretching device according to the method described in
Example 1.
Comparative Example 2
1. Preparation of a catalyst active component: the same as that described in
Example 3.
2. Preparation of propylene polymer composition
The polymerization reactions were continuously carried out in two loop

reactors in series. Firstly, the catalyst active component, triethylaluminum as a
co-catalyst component and cyclohexylmethyldimethoxysilane (in a mass ratio of
1:10:2) were continuously added to a prepolymerization reactor, to which adequate
liquid propylene was fed for prepolymerization at 15°C for 6 min. The catalyst as
prepolymerized was continuously added to the first loop reactor, to which
propylene, ethylene and hydrogen in a mass ratio of 31000:110:6 were fed to carry
out the random copolymerization reaction of propylene for 1 h. Thereafter, the
reactants were transferred to the second loop reactor for carrying out the
homopolymerization reaction of propylene, to which fresh propylene and hydrogen
in a mass ratio of 15000:3 were supplemented. The polymerization temperature in
the two loop reactors was 70°C, and the yield ratio in the first and second loop
reactors was controlled at 60:40. The properties of the polymer composition as
obtained in the form of powder were shown in Table 1.
The hydrogen amounts in the two reactors were controlled so that the MFR
value of the propylene copolymer is higher than that of the propylene
homopolymer.
3. Production of BOPP film: the same as that described in Example 1. The
properties of the film as obtained were shown in Table 3.





As seen from the data of BOPP films shown in Table 3, in comparison with the
high-stiffness BOPP films produced in the prior art (cf. Comparative Examples 1-2),
the BOPP films produced by the polymer compositions of the present invention (cf.
Examples 1-4) had transverse Young modulus higher by 20-40%, and longitudinal
Young modulus higher by 20%, as well as higher tensile strength
(longitudinal/transverse) and lower thickness derivation. Meanwhile, other
properties of the BOPP films described herein are comparative to those in the
Comparative Examples.

WE CLAIM;
1. A propylene polymer composition comprising propylene random
copolymer and propylene homopolymer; wherein the propylene random
copolymer is a copolymer of propylene and ethylene, optionally
comprising one or more alpha-olefins of C4-C10; the propylene polymer
composition has an overall isotacticity index, as determined by nuclear
magnetic resonance method, of greater than or equal to 96.5%, and an
ethylene content of 0.3 wt% to 0.8 wt%.
2. The propylene polymer composition as claimed in claim 1, wherein the
melt flow rate of the propylene random copolymer is lower than that of
the propylene homopolymer.
3. The propylene polymer composition as claimed in claim 1, which has
an overall isotacticity index of greater than or equal to 97%.
4. The propylene polymer composition as claimed in claim 1, which has
an overall isotacticity index of greater than or equal to 97.5%.
5. The propylene polymer composition as claimed in claim 1, which has a
Dispersion index R of less than or equal to 2.5 according to the
crystallization distribution curve as determined by a CRYSTAF, model
200.
6. The propylene polymer composition as claimed in claim 1, which has a
Dispersion index R of less than or equal to 2.0 according to the
crystallization distribution curve as determined by a CRYSTAF, model
200.

7. The propylene polymer composition as claimed in claim 1, wherein the
content of fraction soluble in xylene at room temperature 25°C is less
than 3.0 wt%.
8. The propylene polymer composition as claimed in claim 1, wherein the
propylene random copolymer has a melt flow rate of 0.05-0.5 g/10 min,
and the propylene polymer composition has a melt flow rate of 1-8 g/10
min, as determined under a load of 2.16 kg at 230°C according to the
method of ISO 1133.
9. The propylene polymer composition as claimed in claim 1, wherein the
propylene random copolymer has a melt flow rate of 0.1-0.3 g/10 min,
and the propylene polymer composition has a melt flow rate of 1-3 g/10
min.

10. The propylene polymer composition as claimed in claim 1, which has
a molecular weight distribution index Mw/Mn of 4-10.
11. The propylene polymer composition as claimed in claim 1, wherein
the mass ratio of the propylene random copolymer and the propylene
homopolymer is 30:70-70:30.
12. The propylene polymer composition as claimed in claim 1, comprising
propylene random copolymer and propylene homopolymer, wherein the
propylene random copolymer is a copolymer of propylene and ethylene,
and the propylene polymer composition is characterized by having:
(1) an overall isotacticity index, as determined by nuclear magnetic
resonance method, of greater than or equal to 97%;

(2) an ethylene content of 0.3-0.8 wt%; and
(3) a Dispersion index R of less than or equal to 2.5 according to the
crystallization distribution curve as determined by a CRYSTAF, model
200.

13. The propylene polymer composition as claimed in claim 12, wherein
the content of fraction soluble in xylene at room temperature 25°C is less
than 2.6 wt%, and the propylene polymer composition has a melt flow
rate of 1-3 g/10 min, wherein the propylene random copolymer has a
melt flow rate of 0.1-0.3 g/10 min.
14. A method for preparing the propylene polymer composition as
claimed in claim 1, which comprises, in the presence of a Ziegler-Natta
catalyst having high stereo-selectivity, two-step polymerization reactions
as follows: copolymerizing propylene with ethylene and optionally one or
more alpha-olefms of C4-C10 to obtain a propylene random copolymer;
and homopolymerizing propylene to obtain a propylene homopolymer;
wherein, the amounts of molecular weight regulator used in the two-step
polymerization reactions are controlled so that the melt flow rate of the
propylene random copolymer is lower than that of the propylene
homopolymer; and the yield ratio of the copolymerization and
homopolymerization of propylene is 30:70 to 70:30.
15. The method as claimed in claim 14, wherein the two-step
polymerization reactions are continuously carried out in at least two
reaction zones in series.

16. A method as claimed in claim 14, which comprises subjecting
propylene to continuous random copolymerization and
homopolymerization reactions in two loop reactors in series; wherein, in
the presence of a Ziegler-Natta catalyst having high stereo-selectivity, the
random copolymerization reaction of propylene and ethylene is carried
out in the first loop reactor for a certain time, thereafter the reactants are
transferred to the second loop reactor for carrying out the
homopolymerization reaction of propylene; and wherein, a molecular
weight regulator is added in different amounts to the first and second
loop reactors, so that the MFR value of the propylene copolymer in the
first stage is lower than that of the propylene homopolymer in the second
stage; the yield ratio in the first and second loop reactors is about 65:35
to 55:45, the polymerization temperature in the two loop reactors is
controlled in the range of 60-80°C, and the polymerization reactions are
liquid phase bulk reactions.
17. A method as claimed in claim 14, wherein the Ziegler-Natta catalyst
having high stereo-selectivity comprises a Ti-containing active solid
catalyst component, an organic aluminum compound as a co-catalyst
component, and an organic silicon compound as an external electron
donor component.
18. A method as claimed in claim 17, wherein, in the Ziegler-Natta
catalyst having high stereo-selectivity, the ratio of the organic aluminum
compound as a co-catalyst component and the organic silicon compound
as an external electron donor component, based on the molar ratio of
A1/Si is 4-30.

19. A oriented film produced by the propylene polymer composition as
claimed in claim 1, which is single- or multi-layer, uni- or bi-axially
oriented film, and the multi-layer oriented film has at least one layer
containing said propylene polymer composition.
20. The film as claimed in claim 19, wherein said oriented film is
biaxially oriented film, and the biaxially oriented film has, in the absence
of any stiffening agent, a transverse Young modulus of > 5,000 MPa, and
a longitudinal Young modulus of > 2,400 MPa.


ABSTRACT

TITLE: A PROPYLENE POLYMER COMPOSITION
This invention relates to a propylene polymer composition comprising
propylene random copolymer and propylene homopolymer; wherein the
propylene random copolymer is a copolymer of propylene and ethylene,
optionally comprising one or more alpha-olefins of C4-C10; the propylene
polymer composition has an overall isotacticity index, as determined by
nuclear magnetic resonance method, of greater than or equal to 96.5%,
and an ethylene content of 0.3 wt% to 0.8 wt%.

Documents:

02566-kolnp-2007-abstract.pdf

02566-kolnp-2007-claims.pdf

02566-kolnp-2007-correspondence others.pdf

02566-kolnp-2007-description complete.pdf

02566-kolnp-2007-form 1.pdf

02566-kolnp-2007-form 2.pdf

02566-kolnp-2007-form 3.pdf

02566-kolnp-2007-form 5.pdf

02566-kolnp-2007-international publication.pdf

02566-kolnp-2007-pct request form.pdf

02566-kolnp-2007-priority document.pdf

2566-KOLNP-2007-(20-02-2012)-PETITION UNDER RULE 137.pdf

2566-KOLNP-2007-(28-11-2011)-ABSTRACT.pdf

2566-KOLNP-2007-(28-11-2011)-CLAIMS.pdf

2566-KOLNP-2007-(28-11-2011)-DESCRIPTION (COMPLETE).pdf

2566-KOLNP-2007-(28-11-2011)-EXAMINATION REPORT REPLY RECIEVED.PDF

2566-KOLNP-2007-(28-11-2011)-FORM-1.pdf

2566-KOLNP-2007-(28-11-2011)-FORM-2.pdf

2566-KOLNP-2007-(28-11-2011)-FORM-3.pdf

2566-KOLNP-2007-(28-11-2011)-OTHERS.pdf

2566-KOLNP-2007-CORRESPONDENCE 1.2.pdf

2566-KOLNP-2007-CORRESPONDENCE 1.3.pdf

2566-KOLNP-2007-CORRESPONDENCE 1.4.pdf

2566-KOLNP-2007-CORRESPONDENCE OTHERS 1.1.pdf

2566-KOLNP-2007-EXAMINATION REPORT 1.1.pdf

2566-KOLNP-2007-EXAMINATION REPORT.pdf

2566-KOLNP-2007-FORM 18 1.1.pdf

2566-KOLNP-2007-FORM 26 1.1.pdf

2566-KOLNP-2007-FORM 26.pdf

2566-KOLNP-2007-FORM 3 1.1.pdf

2566-KOLNP-2007-FORM 3.pdf

2566-KOLNP-2007-FORM 5 1.1.pdf

2566-KOLNP-2007-FORM 5.pdf

2566-kolnp-2007-form-18.pdf

2566-KOLNP-2007-GRANTED-ABSTRACT.pdf

2566-KOLNP-2007-GRANTED-CLAIMS.pdf

2566-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2566-KOLNP-2007-GRANTED-FORM 1.pdf

2566-KOLNP-2007-GRANTED-FORM 2.pdf

2566-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2566-KOLNP-2007-OTHERS 1.1.pdf

2566-KOLNP-2007-OTHERS.pdf

2566-KOLNP-2007-PA.pdf

2566-KOLNP-2007-REPLY TO EXAMINATION REPORT 1.1.pdf

2566-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf

2566-KOLNP-2007-TRANSLATED COPY OF PRIORITY DOCUMENT.pdf


Patent Number 253628
Indian Patent Application Number 2566/KOLNP/2007
PG Journal Number 32/2012
Publication Date 10-Aug-2012
Grant Date 07-Aug-2012
Date of Filing 10-Jul-2007
Name of Patentee BEIJING RESEARCH INSTITUTE OF CHEMICAL INDUSTRY, CHINA PETROLEUM & CHEMICAL CORPORATION
Applicant Address NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING
Inventors:
# Inventor's Name Inventor's Address
1 YU, LUQIANG NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
2 ZHANG, SHIJUN NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
3 QIAO, JINLIANG NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
4 SONG, WENBO NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
5 MA, QINGSHAN NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
6 ZHANG, WEI NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013,CHINA
7 WANG, LIANGSHI NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
8 WANG, XI NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
9 TANG, HAO NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
10 LIU, RONGMEI NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013, CHINA
11 GUO, MEIFANG NO. 14, BEISANHUAN EAST ROAD, CHAOYANG DISTRICT, BEIJING 100013,CHINA
PCT International Classification Number C08L 23/10
PCT International Application Number PCT/CN 2006/000115
PCT International Filing date 2006-01-23
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 200510004901.9 2005-01-28 China