JPS59117506A - Film of crystalline propylene-alpha-olefin copolymer - Google Patents

Abstract

PURPOSE:The titled film having low greasiness even with high content of comonomer, having improved opening properties, cold resistance, etc., obtained by decomposing a crystalline propylene-alpha-olefin copolymer having specific physical properties to give a copolymer, makingit into a film. CONSTITUTION:First, a crystalline propylene-alpha-olefin random copolymer having 93-75mol% propylene unit content, and >=2.5dl/g intrinsic viscosity in tetralin at 135 deg.C is decomposed by thermal decomposition using a radical generator consisting of an aliphatic organic peroxide in an extruder with kneading, a copolymer having >=1.35dl/g intrinsic viscosity of xylene soluble component in tetralin at 20 deg.C obtained by this decomposition is made into a film, to give the desired film. EFFECT:Having improved heat sealability.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to crystalline propylene-α-olefin copolymer films with improved film properties.

Crystalline propylene-α-olefin copolymer (hereinafter abbreviated as "propylene copolymer") has superior strength (cold resistance) at low temperatures below 0°C compared to propylene homopolymer, and has excellent strength at lower temperatures. Heat sealing (low temperature heat sealability) is possible. Although low-density polyethylene films are superior in terms of cold resistance and low-temperature heat-sealing properties, propylene copolymer films are less sticky and have superior transparency and scratch resistance compared to low-density polyethylene films. Therefore, it is widely used as a single film or as a composite film with a base film such as a biaxially oriented polypropylene film.

In general, the cold resistance and low-temperature heat-sealing properties of propylene copolymer films are improved by increasing the content of one unit of comonomer in the copolymer;
The characteristics of propylene copolymers tend to be lost. The reason for this is that as the content of one comonomer unit in the copolymer increases, the atactic polymer component becomes more contained in the copolymer, and as a result, the atactic polymer component remaining in the film bleeds. It is thought that it is for the purpose of

The inventors of the present application conducted various studies to solve this problem, and as a result, a copolymer with an intrinsic viscosity (hereinafter [η]) measured in tetralin at 185°C of 2.5 dt/II or more was developed. 20 in the resulting copolymer
°C xylene soluble polymer component (hereinafter 0XIS) [η]
A film made of a copolymer with a d4'7 or higher of 1.85 d4'7 has good stickiness and opening properties, and has good cold resistance and low-temperature heat sealability even when the content of one unit of comonomer is high. The inventors have discovered that an improved film can be obtained, leading to the present invention.

That is, in the present invention, the propylene unit content is 98 to 7.
5 mol % and has an intrinsic viscosity measured in tetralin at 185°C of 2.5°C. A long-life film is produced by forming a film from the copolymer having a molecular weight of Q or higher.

The present invention will be explained in more detail below.

CXS in the copolymer used in the film of the invention
Unlike CXS in conventional copolymers, CXS does not worsen the stickiness or openness of the film, or the extent to which it deteriorates is significantly small.

As shown in Japanese Patent Application Laid-Open Nos. 51-24685, 58-7'/86, and 54-118486, conventionally, the content of CX8 and the stickiness of the film,
Considering that a very good correlation with blocking existed for propylene homopolymers and copolymers, the copolymers used in the films of the present invention have higher CxS than conventional copolymers. It is surprising that the stickiness (blocking) of the film is so small, although it is by no means small.

The polymer component in the copolymer that is soluble in xylene at 20°C corresponds to a so-called atactic polymer component. CX8 completely dissolves the copolymer in heated xylene, slowly cools it to 20°C, separates the precipitated copolymer, and then recovers the polymer dissolved in xylene at 2o°C by evaporating the solvent. obtained by Details of the experimental method will be described later.

Crystalline propylene-α- which is the raw material for the film of the present invention
The olefin random copolymer has [η] of 2.5 dl
A copolymer obtained by decomposing a crystalline propylene-α(5)-olefin random copolymer (hereinafter referred to as "pre-decomposition copolymer") having a molecular weight of 711 or more, and in which the [η of OXS in the copolymer is ] is 1.85 dL/f1 or more.

The intrinsic viscosity of the copolymer before decomposition is preferably 2.7 to 4.
0 dL/f/, more preferably 2.7 to 8.5 d
t/I/. In addition, [η
] is preferably 1.4 to 1.6 dl/I. [η] of OXS in the copolymer after decomposition is 1.40 dL/
'1 or more is preferred. CXS in the copolymer after decomposition is determined by the ratio M between its weight average molecular weight MJff and number average molecular weight Mn.
It is preferable that w/MN is 8.5 or less.

As a method for decomposing the copolymer before decomposition, methods such as thermal decomposition, which are known as methods for decomposing polypropylene, can be used, but for example, a method of decomposing while melt-kneading in an extruder is industrially advantageous. It is. For efficient decomposition, it is preferable to use a radical generator. Aliphatic organic peroxides are preferably used in film applications, where odor and color (6) are particularly problematic. Examples of preferred aliphatic organic peroxides include 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(
Examples include tert-butylperoxy)hexene-8. The amount of these organic peroxides used is preferably 0.005 to 1% by weight based on the copolymer before decomposition.
More preferably, it is 0.2 to 0.08% by weight, and the decomposition temperature is preferably in the range of 180 to 800°C.

In addition, the degree of decomposition is determined by setting [η] of the copolymer before decomposition to 0.4.
It is preferable to reduce the amount by more than 10%.

Crystalline propylene obtained by decomposition in this way
A film formed from an α-olefin copolymer has significantly improved properties compared to a film formed from a conventional copolymer. i.e. conventional copolymers with equal comonomer content and melt flow index (
The stickiness and transparency of the film of the present invention are significantly improved, and the low-temperature heat-sealability of the film is also improved compared to a film formed by forming a film in which the molecular weight is adjusted using a molecular weight regulator coexisting during copolymerization. do.

Furthermore, the film of the present invention is characterized in that the amount of extractables when extracted with 50°C (7) n-hexane is smaller than films obtained from conventional copolymers.

When a 2.5 am square film specimen with a thickness of 0.1 m or less is extracted for 2 hours, the amount extracted is 8% by weight or less, usually 2.5% by weight or less. When a film made of the copolymer of the present invention is used for packaging oil-based foods, it is very preferable that the amount extracted is small. Further, the film obtained by forming the copolymer of the present invention has a characteristic that deterioration of transparency over time is extremely small.

The range is suitable when the copolymer of the present invention is actually processed into a film, and the processed product exhibits useful physical properties.
Melt flow index MFI measured according to JI8 K6758-19TT is o, i or 800g/
10 minutes, particularly preferably within the range of 1.0 to 100 g/100 minutes.

In the present invention, films of various known forms can be processed by various known film forming methods. Further, the film of the present invention can be used alone or as a composite film with other base materials. As for the film forming method, it is industrially advantageous to melt the copolymer and then process it into a film. Specifically, cast films using a T-die film forming machine, blown films using an inflation processing machine, stretched films stretched in the -axial or biaxial direction, and films with other base materials such as polypropylene films, polyethylene terephthalate films, and paper are used. It can take the form of a composite film or the like. Composite films can be obtained by adhesive bonding, extrusion coating, lamination, coextrusion, and other methods. The details of the film forming method are described in various documents, for example, McGraw-Hill Publication (9).
) (7) [%Modern Plastics Ency
clopedia ) J (7) 12 B 1-,
It is detailed in the 1962 edition.

The crystalline propylene-α-olefin random copolymer of the present invention contains propylene units in an amount of 93 to 75 mol % in the case of a binary polymer and 96 to 85 mol % in an octuary copolymer. If there are too many propylene-containing units, the cold resistance and low-temperature heat sealability will be unsatisfactory when formed into a film. If the proportion of propylene units is too small, the properties as a crystalline propylene copolymer, ie, moderate elasticity and scratch resistance, will be unsatisfactory.

The α-olefin as a comonomer is selected from α-olefins other than propylene, preferably α-olefins having 2 to 18 carbon atoms. Such α-olefins include:
Ethylene, 1-butene, 1-pentene, 1-hexene,
Examples include 4-methyl-1-pentene, 1-octene, 1-decene, etc., but there is no reason to be limited to the α-olefins shown in Example (10). However, mainly for economic reasons, ethylene and 1-
Butene is a preferred comonomer.

The number of comonomers is not limited to one type, and two or more types may be present. Therefore, the copolymers of the present invention are specifically propylene-ethylene binary copolymers, propylene-1-butylene binary copolymers, propylene-ethylene-1
-butylene 28-element copolymer, etc. can be exemplified.

In the case of a propylene-ethylene binary copolymer, the propylene content is preferably 98 to 80 mol%, particularly 98 to 80 mol%.
5 mol% is preferred. In the case of the propylene-1-buty 22-element copolymer, the propylene content is preferably 90 to 77 mol%, particularly preferably 87 to 88 mol%. In the propylene-ethylene-1-butylene 28-element copolymer, the propylene content is preferably 96 to 85 mol%, particularly 9
5 to 88 mol% is preferable, and the ethylene content is 1.5 to 88 mol%.
11 mol% is preferred, particularly 8 to 6 mol%,
The 1-butene content is preferably 2 to 16 mol%, especially 2
~6 mol% is preferred.

The random copolymer of the present invention is not necessarily a "random copolymer" in a statistically strict sense, that is, the chain distribution of propylene and α-olefin (which can be quantified by carbon-18 nuclear magnetic resonance) conforms to the Bernoulli statistical law. There is no need for a strict copolymer. As long as the definition of the present invention is followed, there may be a distribution in the composition.

In the present invention, the term "propylene-α-olefin random copolymer" is used to distinguish it from the so-called "propylene-α-olefin block copolymer." The copolymers of the invention therefore contain no more than 20% by weight, preferably no more than 5% by weight, particularly preferably no more than 2% by weight of homopolymers of propylene. Otherwise, the transparency of the film will deteriorate significantly. Furthermore, if the copolymer is not crystalline, the stiffness and scratch resistance of the film will be unsatisfactory, and the characteristics of the crystalline propylene copolymer film will be lost.

The pre-degraded copolymer used in the present invention has a strong isospecificity (1
sospecific) It can be produced by copolymerizing a mixture of propylene and α-olefin using a Ziegler-Natsuta catalyst. The catalyst used preferably has high isospecificity.

'The catalyst that can be suitably used is a composite solid compound of titanium trichloride or a magnesium compound and a titanium compound whose transition metal catalyst component has a layered crystal structure, and the typical metal component is an organoaluminum compound. The catalyst can include a known electron donating compound as a third component.

Titanium trichloride produced by reducing titanium tetrachloride with various reducing agents can be used. As a reducing agent, metals such as aluminum and titanium,
Hydrogen, organometallic compounds, etc. are known. Typical titanium trichloride produced by metal reduction is:
(18) A titanium trichloride composition (Ti0za AA ) containing aluminum chloride activated by reducing titanium tetrachloride with metallic aluminum and then milling in an apparatus such as a ball mill or a vibratory mill. For the purpose of improving isospecificity, polymerization activity, and/or particle properties, a compound selected from ethers, ketones, esters, aluminum chloride, titanium tetrachloride, etc. may be coexisting during the grinding.

More preferred titanium trichloride for the purposes of the present invention is obtained by reducing titanium tetrachloride with an organoaluminum compound and subjecting the resulting titanium trichloride composition to a contact reaction with an ether compound and a halogen compound simultaneously or sequentially. Titanium trichloride. The ether compound has the general formula R-
0-R"(R' and R2 are alkyl groups having 1 to 18 carbon atoms), especially di-n-butyl ether,
Di-t-amyl ether is preferred, and the halogen compounds include halogens, especially iodine, interhalogen compounds, especially iodine trichloride, titanium halides, especially titanium tetrachloride (14), halogenated hydrocarbons, especially carbon tetrachloride,
Preferably it is selected from 1,2-dichloroethane. Organoaluminum compounds have the general formula AzR”nXa-n (
R" is a hydrocarbon group having 1 to 18 carbon atoms, and X is (3z, Br
, I, where n is a number satisfying 8≧n)l), and particularly preferred are diethylaluminum chloride and ethylaluminum sesquichloride.

Regarding the manufacturing method of these titanium trichlorides, please refer to JP-A No. 4
No. 7-84470, No. 5B-88289, No. 5B=5
No. 1285, No. 54-11986, Patent Application No. 57-26
It is described in detail in Publication No. 507 and the like.

When titanium trichloride having a layered crystal structure is used as a transition metal compound component, the typical metal compound component has the general formula AzR'mX5-m (R' is a hydrocarbon group having 1 to 18 carbon atoms, X is Cz, Br , a halogen selected from I,
Preferably, m is an organoaluminum compound represented by 8≧m>0). Particularly preferred organoaluminum compounds for the purposes of the present invention are those in which W is an ethyl or isobutyl group, m
is a compound in which 2.5≧m≧1.5.

Specific examples include diethylaluminium chloride, diethylaluminum bromide, diethylaluminium iodide, and mixtures of these with triethylaluminum or ethylaluminum dichloride.

When a third component described below is used in combination, an organic aluminium compound with 8≧m≧2.5 or 1.5≧m>0 can also be suitably used for the purpose of the present invention.

The ratio of organoaluminum compound and titanium trichloride is 1:1
Catalysts consisting of titanium trichloride and organoaluminium, which can be selected from a wide range of molar ratios from 1000:1 to 1000:1, can contain known third components. As the third component, ε−
Examples include ester compounds such as caprolactam, methyl methacrylate, ethyl benzoate, and methyl toluate, phosphite esters such as triphenyl phosphite and tributyl phosphite, and phosphoric acid derivatives such as hexamethylphosphoric triamide. be able to.

The amount of the third component to be used must be determined experimentally for each individual compound since the acting force differs depending on the compound, but it is generally less than equimolar to the organoaluminium.

When a composite solid compound of a magnesium compound and a titanium compound is used as the transition metal solid catalyst component of the catalyst, the typical metal catalyst component is an organoaluminum compound, especially a compound with the general formula AtR'pXs-p<it4 having 1 to 18 carbon atoms.
a hydrocarbon group, X is Ct.

A compound represented by a halogen selected from Br, I, and p (8≧p>2) is preferred. Specific examples include triethylaluminum, triisobutylaluminum, and mixtures of these with diethylaluminum chloride or diisobutylaluminum chloride.

Preferably, the catalyst further comprises an electron-donating compound, especially an aromatic monocarboxylic acid ester. The electron-donating compound is preferably used in an amount of 1 mol or less, particularly in the range of 0.1 to 0.5 mol, per 1 (17) mol of the organoaluminum compound.

As a composite solid compound of a magnesium compound and a titanium compound, titanium trichloride containing magnesium chloride obtained by reducing titanium tetrachloride with an organomagnesium compound can also be used, but it is preferable to convert a solid magnesium compound into a liquid phase. A so-called "supported catalyst" produced by catalytic reaction with a titanium compound is used. Solid magnesium compounds are electron-donating compounds, especially aromatic monocarboxylic acid esters, ether compounds, alcohol-Jl/
It is preferable that it contains lfJ, sulfuric acid, and/or phenols. The aromatic monocarboxylic acid ester can also be present at the time of the contact reaction with the titanium compound.

The composite solid compound of the above-mentioned magnesium compound and titanium compound is described in many patent publications, but the catalyst suitable for the purpose of the present invention is disclosed in Japanese Patent Laid-Open No. 54-11.
No. 2988, No. 54-119586, No. 56-804
No. 07, No. 57-(18) No. 59909, No. 57-59910, No. 57-599
No. 11, No. 57-59912, No. 57-59914, No. 57-59915, No. 57-59916, No. 5
4-112982 Copolymer before decomposition It can be obtained by copolymerizing a mixture of propylene and α-olefin in the gas phase or liquid phase in the presence of the above catalyst. In the case of copolymerization in a liquid phase, the monomers can be dissolved in an inert hydrocarbon solvent such as hexane or heptane and then copolymerized, or the copolymerization can be carried out in a monomer mixture in a liquid phase.

It is common and effective to adjust the molecular weight by coexisting hydrogen.

Although the copolymerization reaction can be carried out at any temperature and pressure, for the purposes of the present invention it is preferable to select a temperature within the range of 80 to 80°C.

The copolymer of the present invention and its film may contain known additives such as an antioxidant, an ultraviolet inhibitor, a lubricant, an antiblocking agent, an antistatic agent, an antifogging agent, and a nucleating agent, if necessary.

In order to explain the present invention more clearly, comparative examples and examples are described below, but the present invention is not limited only by these examples.

In addition, the characteristic values in the following examples were measured by the following method.

(1) After dissolving 5 g of the xylene-soluble portion of the polymer in 500 °C of boiling xylene, it was slowly cooled to room temperature and left at 20°C for 4 hours, after which the precipitated polymer was distributed from house to house. Evaporate xylene from P solution,
The xylene soluble polymer at 20"'C is recovered by vacuum drying at 20"'C.

(2) Gel permeation chromatography (
GPC) WatersAssoc.
model 150-CALC/G
For PO, Showa Denko Co., Ltd. column 8hodax” GP
Connect the S AD-80M/8 in a two-wire type row, and proceed as follows 2.
1 using 1.2.4-trichlorobenzene containing 0.04% by weight of 6-di-t-butyl-p-cresol as a solvent.
Measured at 40°C. The calibration curve has a molecular weight of 2.8
Standard polystyrene from Toyo Soda (Mw/Mn = 1.01
~1.14) Created using 9 types. N B 8
(National Bureau of 5and
ards ) (y) 8 standard Refer
nce Material 7Q6 (Mw/Mn =2
．． When polystyrene (No. 1) was measured by GPC according to the above method, the Mw/Mn was 2.1-2.2.

(8) Melt flow index (MFI) JI8
Measured according to K675B.

(4) △Haze After film formation, 4 films were left at 60°C for 9 hours and then at 28°C for several hours, and the haze value measured according to A8TMDI00B and left overnight at 28°C after film formation. The difference between the haze value and the haze value measured in the same manner for the obtained film was defined as the Δ haze value.

(21) (6) Blocking Two films cut into rectangles of 5 crn x 25 m are stacked horizontally, and 40 fl/ml is evenly distributed over the entire surface of the stacked films.
The two films were brought into close contact by applying a load of di and leaving the film at 60°C for 9 hours. The adhesion strength per 100 d of film adhesion area, that is, the blocking value, is determined by the force required to peel two closely adhered films in a direction perpendicular to the film surface using a blocking tester manufactured by Takasu Seisakusho.

(7) Heat-sealing temperature Two films were stacked together and a heat sealer heated to a predetermined temperature was used to apply a load of 2 to 9 for 2 seconds and the resulting sealed film had a width of 25 m and was left overnight. 28°C
The heat sealing temperature was defined as the temperature of the heat sealer at which the low resistance before peeling was 800 f/25 when peeled at a peeling rate of 200 fins/min and a peeling angle of 180°.

(22) (8) Amount of n-hexane extracted 2.5 cm x 2.5 cm square film 0.51 mm thick was cut into 200-n-
Immerse it in a condenser flask containing hexane and heat at 50°C for 2 hours while stirring with a magnetic stirrer. The P solution obtained by filtration while hot is dried to obtain an extract.

The extract is vacuum dried at 110° C. for 1 hour, cooled in a desiccator for 80 minutes and weighed.

(9) Intrinsic viscosity Intrinsic viscosity can be determined by measuring the viscosity of a polymer solution completely dissolved in tetralin at 185° C. using an Ubbelohde viscometer according to a conventional method. In order to prevent the decomposition of the polymer during the measurement operation, the solvent tetralin contained a suitable antioxidant, for example, about 0.2% by weight of 2,6-di-t-butyl-p-cresol. .

Example 1 (1) A stainless steel autoclave with a stirrer and a copolymerization internal volume of 880 tons was sufficiently replaced with propylene, and 110 tons of purified industrial hebutane was added to the autoclave, and 19 tons of propylene was added to the autoclave.
The temperature was raised to 0°C. 16 diethylaluminium chloride
The 511 titanium trichloride catalyst component was introduced into the autoclave at 12.8F and hydrogen pressure, and the temperature was immediately raised to 50C. The titanium trichloride catalyst component used was disclosed in JP-A-47-84478.
0.27 parts by weight of polypropylene per 1 part by weight of the titanium trichloride was formed by polymerizing propylene at 80° C. on titanium trichloride made by Marubeni-Solvay by the manufacturing method described in the above publication.

After raising the temperature to 50°C, while maintaining this temperature, the concentrations of ethylene and hydrogen in the gas phase in the autoclave were each 8°C.
．． 5 and 6.0% by volume, and the total pressure was 6.0% by volume.
The copolymerization reaction was continued while supplying propylene, ethylene, and hydrogen to a pressure of 0 Kg/d (gauge pressure).

After raising the temperature to 50°C, the amount of propylene supplied to the autoclave reached 25 Kf after 8 hours and 40 minutes, so the monomer was purged under reduced pressure, and 1O11 of isobutanol, 21 tons of propylene oxide, and 110 tons of heptane were charged into the autoclave, and heated at 60°C for 80 minutes. Stirred. By separating the contents into solid and liquid using a centrifuge and drying the solid portion, 26,6
Powder copolymers of Nos. 5 to 5 were obtained.

The ethylene content of the obtained powder copolymer was 9.2 mol%
, the intrinsic viscosity measured in tetralin at 185°C is 2.
It was 87 dL/f. In addition, 20 in the powder copolymer
The xylene soluble portion (CXS) at °C is 12.9% by weight.
The intrinsic viscosity of CXS was 2.25 dt/g.

(2) Granulation (26) Rum and 0.045 parts by weight of 2.5-dimethyl-2,
5-di-t-butylperoxyhexane was mixed. The mixture was melt extruded in a 40°σ single screw extruder heated to 220°C, and the extruded strands were cut to obtain pellets. The residence time of the copolymer in the extruder is approximately 1.5 minutes.

The intrinsic viscosity of the resulting pellets is 1.65 dt/fl.
, the melt flow index is 5. Of/10 minutes, the melt expansion ratio was 1.06. In addition, (7) O in the pellet
X 8 Ha12.8 Jtli% ”'Qlo Li,C
The intrinsic viscosity of XS is 1.66 dt/l, Mw/ of CXS
Mn was 2.2.

(8) Film Formation The pellets obtained in (2) were formed into a cast film with a thickness of 80 microns using a T-die film forming machine. The temperature of the die is 2
The temperature of the 20°C1 cooling roll was 28°C.

(26) The properties of the film were as follows: △ Haze 2.8
%, blocking 58 g/100-, heat sealing temperature 115° C0. When the above film was extracted with n-hexane at 50° C. for 2 hours, the amount extracted was extremely small at 0.8% by weight.

Example 2 A copolymerization reaction was carried out in the same manner as in Example 1, except that the catalysts used in the copolymerization reaction were 165 g of diethylaluminum chloride and 18.8 g of C-caprolactam 15-1 titanium trichloride catalyst component.

For the obtained powder copolymer, the ethylene content was 10
．． 4 mol%, the intrinsic viscosity was 2.97 dl/l, and the CX8 content was 18.6% by weight. Further, the intrinsic viscosity of CXS in the powder copolymer was 2.16 dt/fl.

For the pellets obtained, the intrinsic viscosity is 1.62 dt
/I, melt flow index is 5.8f/10min,
Melt expansion ratio is 1.06, CXS content is 22.8% by weight
Met. Intrinsic viscosity of CX8 in pellets is 1.56
dt/Q and Mw/Mn were 2.6.

The properties of the resulting 30 micron thick cast film were as follows: Haze 2.7%, blocking 120g/100-,
Heat seal temperature 111°C, 50°Cn-hexane extract 2.2% by weight.

Comparative Example 1 The same procedure as in Example 1 (1) was carried out except that the hydrogen concentration in the gas phase in the autoclave during the copolymerization reaction was 18.0% by volume, and the decomposing agent 2,5-dimethyl-2 ,5-di-t-
Example 1 except that butyl peroxyhexane was not mixed.
Granulation was carried out in the same manner as in (2).

The resulting pellets had an ethylene content of 9.7 mol %, a polar [[ of 1.67 dL/I, a melt flow index of 7.91//10 minutes, and a melt expansion ratio of 1.86. In addition, CXS in the pellet was 14.4% by weight,
The intrinsic viscosity of CXS is 1,22 (11/11, M,
w/Mn is 8.2 degrees.

The properties of a cast film with a thickness of 80 microns obtained from this pellet in the same manner as in Example 1 (8) were as follows: Haze 8.4%, blocking 120 f/100- or more, heat Seal temperature 118°C 150°C n-hexane extract 4.1% by weight.

Comparing the properties of this film with those of Examples 1 and 2, the superior properties of the copolymer film of the present invention become clear. That is, the copolymer of Comparative Example 1, even though its ethylene content and CX8 content have values intermediate between those of the copolymers of Examples 1 and 2, respectively, , ΔHaze, and blocking all show worse (higher) values than both Examples 1 and 2. In other words, the copolymer film of the present invention has lower heat sealing temperature, △ haze,
Excellent blocking balance. Also, 50
The amount of copolymer extracted in n-hexane at °C is also much lower in the (29) films of Examples 1 and 2 than in Comparative Example 1, which is very preferable.

Comparative Example 2 and Example 8 The powder copolymers of Comparative Example 1 and Example 1 were used in Comparative Example 1 and Example 1, respectively.
The amount was changed to L-10.8 parts by weight.

The obtained pellets were processed into a blown film with a thickness of 80 microns using a water-cooled blown film processing machine. The temperature of the die is 195°C1 The temperature of the cooling water is 25°C
The °C1 blow ratio was 1.5.

Regarding the opening property of the film folded with a nip roll, the film using the copolymer of Example 1 opened easily by pinching it with the thumb and index finger and moving it in the opposite direction once or twice, but compared to A film using the copolymer of Example 1 (
80) So, no matter how many times I moved my finger in the opposite direction, the mouth wouldn't open, and only after massaging it with both hands did it open.

In terms of openness, the film of Example 8 is practical, but
The film of the comparative example cannot be put to practical use at all.

The properties of the film after opening are shown in Table 1.

1st Table: Locking (g/100i) Peeling
17 In Table 1, "Peeling" in the blocking section indicates that the blocking was measured immediately after the operation, and it means that the blocking was extremely small.

Comparative Example 8 10Kg of liquefied propylene was introduced into a polymerization tank with an internal volume of 8801, and heated to 60°C until the ethylene concentration in the gas phase was 2.
．． Ethylene was added until the concentration was 2%. 2.1 units of diethylaluminium methyl methacrylate and 8.1 g of the same titanium trichloride as used in Example 1 were added, and copolymerization was carried out for 2 hours and 80 minutes. During this time, the temperature was kept at 60°C, and the concentrations of ethylene and hydrogen in the gas phase were kept at an average of 2.7 and 8.0°C, respectively.
It was kept at 0%. Copolymerization was stopped by adding 8 t of isobutanol and 1 t of propylene oxide, and the mixture was stirred at 60°C for 80 minutes. The stirring was stopped and the mixture was allowed to stand for 5 minutes, and the liquid was extracted from the pipe. Add liquefied propylene 67- and heat at 60°C.
A powder copolymer was obtained by repeating the series of operations twice, including stirring for 5 minutes, standing still for 5 minutes, and then drawing out the liquid again.

Granulation and film formation were the same as in Example 1 except for the matters listed in Table 2.

In Comparative Example 8, the copolymer before decomposition had [η] of 2.
Because 8 8 dllII and a low [η] were used, the blocking value was large, and the heat sealing temperature was low despite the large amount of etch B.

Table 2 (Completed No. 88) Procedural Amendment (Voluntary) January 7, 1980 1. Indication of the case 1988 Patent Application No. 280582 2. Name of the invention Crystalline propylene-α-olefin copolymer film 8. Relationship with the person making the amendment Patent applicant address 5-15 Kitahama, Higashi-ku, Osaka Name (20
9) Hijikata, Representative of Sumitomo Chemical Industries, Ltd.
Take 4. Address of agent: 5-15 Kitahama, Higashi-ku, Osaka. Number of inventions increased by the amendment: 16. Claims column (1) of the specification to which the amendment refers. 7. Contents of the amendment as shown in the attached sheet.

Claims (1) Crystalline propylene having a propylene unit content of 93 to 75 mol% and an intrinsic viscosity of 2.51z1 or more when measured in tetralin at 185°C.
A copolymer obtained by decomposing an α-olefin random binary copolymer, and measured at 185°C in tetralin, a polymer component of the copolymer that is soluble in xylene at 20°C. The intrinsic viscosity is 1. : A film obtained by forming the copolymer having a ratio of 5 di/9 or more.

Claims (2)

[Claims] (1) A polymer component in tetralin that has a propylene unit content of 98 to 75 mol%, has an intrinsic viscosity of 2.5 dL/I or more measured at 185°C in tetralin, and is soluble in ammonium. A film obtained by forming the copolymer having an intrinsic viscosity of 1.85 dL/g or more as measured at 135°C. (2) Crystalline propylene-α-olefin random 8-component having a propylene unit content of 96 to 85 mol% and an intrinsic viscosity of 2.5 dt/f/ or more as measured in tetralin at 185°C A copolymer obtained by decomposing a polymer, and at 20°C in the copolymer.
185 μm in tetralin, a polymeric component soluble in xylene.