JP2000095878A - Production of propylenic resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a propylenic resin film having excellent flexibility, transparency and gloss and not having an environment- polluting property. SOLUTION: This method for producing a propylenic resin film comprises subjecting a resin composition to a film-forming process by a T-die method or a downward water-cooling inflation method at a cooling temperature of 30-70 deg.C. The resin composition comprises 0.005-0.1 pt.wt. of a crystal-nucleating agent and 100 pts.wt. of a resin component which comprises 97-10 wt.% of a propylenic resin and 3-90 wt.% of a vinyl aromatic elastomer. The vinyl aromatic elastomer is preferably a hydrogenated styrene-butadiene random copolymer or a hydrogenated styrene-isoprene-styrene block copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a propylene-based resin film.

[0002]

2. Description of the Related Art Polymer resin films are used for packaging various articles such as textiles, clothing, bread, noodles, toilet paper, and the like, and are particularly used for applications requiring high transparency, high gloss, flexibility, and the like. Uses a soft vinyl chloride resin film. However, since a soft vinyl chloride resin film contains a large amount of a plasticizer, there is an environmental problem, and a propylene-based resin film has recently been used.

As the propylene-based resin film, a stretched propylene-based resin film containing a crystal nucleating agent is used, but has drawbacks in that it has high rigidity, low flexibility, and is liable to be wrinkled.

In order to solve such disadvantages, Japanese Patent Laid-Open Publication No. Hei 7-290649 proposes a laminated film in which a random polypropylene layer is laminated on both sides of an intermediate layer composed of random polypropylene and a hydrogenated diene copolymer. However, this laminated film has a disadvantage that it has excellent flexibility but low glossiness.

An object of the present invention is to provide a method for producing a propylene-based resin film which is excellent in flexibility, transparency and gloss and has no environmental pollution in view of the above-mentioned drawbacks.

[0006]

According to the present invention, there is provided a method for producing a propylene-based resin film.
100 parts by weight of a resin component consisting of 3 to 90% by weight of a vinyl aromatic elastomer and 0.005% by weight of a crystal nucleating agent.
The resin composition consisting of 0.1 to 0.1 parts by weight is cooled at a temperature of 30 to 70 ° C. by a T-die method or a downward water-cooled inflation method.
The film is characterized by being formed by.

The resin component used in the present invention comprises 97 to 10% by weight of a propylene resin and 3 to 90% by weight of a vinyl aromatic elastomer. As the propylene-based resin, those generally commercially available as a propylene-based resin can be used, and when ethylene is copolymerized,
It is preferable because of its excellent flexibility and transparency.
Preferably, it is copolymerized in an amount of at least% by weight.

The above vinyl aromatic elastomer is A- (BA) _m (m represents an integer of 1 or more) obtained by copolymerizing a vinyl aromatic compound (A) and a conjugated diene (B). Or a block copolymer or a random copolymer represented by (AB) _n (n represents an integer of 1 or more) and a hydrogenated product of these copolymers; AB type copolymers are preferred.

The vinyl aromatic compound includes, for example, styrene, t-butylstyrene, α-methylstyrene, p-methylstyrene, 1,1-diphenylstyrene and the like, and styrene and α-methylstyrene are preferred. Examples of the conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, and 2-methyl-1,3-
Examples thereof include pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octadiene, and chloroprene, and 1,3-butadiene and isoprene are preferred.

As the vinyl aromatic elastomer, a styrene-butadiene random copolymer, a styrene-isoprene-styrene block copolymer and a hydrogenated product thereof are preferable. As the hydrogenated product of the styrene-isoprene-styrene block copolymer, a styrene-ethylene-propylene-styrene copolymer and a hydrogenated styrene-isoprene-styrene block copolymer having 3,4 isoprene bonds are particularly preferable.

The ratio of the propylene resin to the vinyl aromatic elastomer in the above resin component is such that when the ratio of the vinyl aromatic elastomer decreases, the flexibility decreases, and when the ratio increases, the transparency and gloss decrease. The resin content is 97 to 10% by weight, and the vinyl aromatic elastomer is 3 to 90% by weight.

The crystal nucleating agent used in the present invention may be any as long as it has a nucleating effect on the propylene-based resin. Condensates, polymer nucleating agents and the like can be mentioned.

Examples of the metal salts of the above organic carboxylic acids include sodium and potassium salts of benzoic acid and para-t
Aluminum salts of -butylbenzoic acid. Examples of the condensate of the above benzaldehyde or a ring-substituted product thereof with a polyhydric alcohol include, for example, dibenzylidene sorbitol, dibenzylidene xylitol, dibenzylidene passitol, monobenzylidene sorbitol, dibenzylidene mannitol, 1,3-di (alkylbenzylidene) Sorbitol, 2,4-di (alkylbenzylidene) sorbitol, 1,3-di (alkoxybenzylidene) sorbitol, 2,4-di (alkoxybenzylidene) sorbitol, alkyl-substituted benzylidenesorbitol and the like.

Examples of the polymer nucleating agent include vinylcycloalkanes such as vinylcyclohexane and vinylcyclopentane, alkyl-substituted styrenes such as pt-butylstyrene and p-methylstyrene, and 3-methylbutene-1,4,4. 4-dimethylpentene-1,4,4-dimethylhexene-1,3,3-dimethylbutene-1,3-methylpentene-1,3-methylhexene-1,3,5
Examples thereof include polymers such as 5-trimethylhexene-1, indene, trialkylallylsilane, and vinylcycloalkene.

The resin composition used in the present invention comprises the above resin component and a crystal nucleating agent. When the amount of the crystal nucleating agent is small, the transparency and gloss are reduced, and when the amount is large, the rigidity is improved. However, 0.005 to 0.1 part by weight is added to 100 parts by weight of the resin component because the flexibility is lowered.

The above resin composition may further contain a lubricant, an antiblocking agent, a plasticizer, a light stabilizer, an antioxidant, a colorant, a processability improver, and an antistatic agent as long as the properties are not deteriorated. And an ultraviolet absorber may be added as necessary.

In the present invention, the above resin composition is formed into a film at a cooling temperature of 30 to 70 ° C. by a T-die method or a downward water-cooled inflation method. That is, the resin composition is kneaded in a heated and molten state using a kneader such as a single-screw extruder, a twin-screw extruder, a Banbury mixer, a kneading roll, a brabender, or a kneader, and the T-die is formed using a conventional extruder. The film is extruded by a water-cooled inflation method or a downward water-cooled inflation method, and a film is formed at a cooling temperature of 30 to 70 ° C.

When the cooling temperature is lowered, precipitates are liable to precipitate on the roll, and the physical properties are apt to change over time. When the cooling temperature is increased, the effect cannot be obtained.
The film is formed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples.

EXAMPLE 1 93 parts by weight of a random copolymerized propylene resin having an MFR of 6.0 g / 10 min, and styrene having 3,4 isoprene bonds.
Isoprene-styrene block copolymer (manufactured by Kuraray Co., Ltd.
Hypla VS-1, styrene content 20%, MFR5)
7 parts by weight and 0.025 parts by weight of dibenzylidene sorbitol were kneaded at 210 ° C. for 10 minutes, and then the thickness of 4 was obtained by the T-die method at a mold temperature of 230 ° C. and a cooling roll temperature of 45 ° C.
A 0 μm propylene resin film was obtained.

Examples 2 to 4 A styrene-isoprene-styrene block copolymer having isoprene 3,4 bonds (manufactured by Kuraray Co., Ltd., Hypla VS-
1, a styrene content of 20%, MFR 5) was replaced with a hydrogenated styrene-isoprene-styrene block copolymer having isoprene 3,4 bonds (manufactured by Kuraray Co., Ltd., Hypla HVS)
-3, styrene content 20%, MFR6) (Example 2), hydrogenated styrene-butadiene random copolymer (Dynalon 1320P, manufactured by Nippon Synthetic Rubber Co., Ltd., styrene content 10%, MFR 3.5) (Example 3) ) And styrene
Ethylene-propylene-styrene block copolymer (manufactured by Kuraray Co., Ltd., Septon 2007, styrene content 30%,
MFR7) (Example 4), except that propylene-based resin film was obtained in the same manner as in Example 1.

Example 5 A propylene-based resin film was obtained in the same manner as in Example 2 except that a film was formed by a water-cooled inflation method at a mold temperature of 230 ° C. and a cooling water temperature of 45 ° C. instead of the T-die method. Was.

Comparative Example 1 100 parts by weight of a random copolymerized propylene resin having an MFR of 6.0 g / 10 min and 0.02 of dibenzylidene sorbitol
After kneading 5 parts by weight at 210 ° C. for 10 minutes, a propylene resin film having a mold temperature of 230 ° C., a cooling roll temperature of 55 ° C. and a thickness of 40 μm was obtained by a T-die method.

Comparative Example 2 A hydrogenated styrene-isoprene-styrene block copolymer having 5 and 4 parts by weight of a random copolymerized propylene resin having an MFR of 6.0 g / 10 minutes and isoprene bonded to 3,4 (Kuraray Co., Ltd., Hypla HVS-3, Styrene content 20%, MF
R6) 95 parts by weight and dibenzylidene sorbitol 0.
After kneading 025 parts by weight at 210 ° C. for 10 minutes, a propylene resin film having a mold temperature of 230 ° C., a cooling roll temperature of 45 ° C. and a thickness of 40 μm was obtained by a T-die method.

Comparative Example 3 A hydrogenated styrene-isoprene-styrene block copolymer having 95 parts by weight of a random copolymerized propylene resin having an MFR of 6.0 g / 10 min and isoprene bonded to 3,4 (Kuraray Co., Ltd., Hypla HVS-3, Styrene content 20%, M
FR6) After kneading 5 parts by weight at 210 ° C. for 10 minutes, T
The die temperature is 230 ° C. and the cooling roll temperature is 55
A propylene-based resin film having a thickness of 40 µm at a temperature of ° C was obtained.

COMPARATIVE EXAMPLE 4 95 parts by weight of a random copolymerized propylene resin having an MFR of 6.0 g / 10 min, and a hydrogenated styrene-isoprene-styrene block copolymer having isoprene 3,4 bonds (manufactured by Kuraray Co., Ltd., Hypla HVS-1; Styrene content 20%, MF
R6) 5 parts by weight and dibenzylidene sorbitol 0.2
After kneading 5 parts by weight at 210 ° C. for 10 minutes, a propylene resin film having a mold temperature of 230 ° C., a cooling roll temperature of 45 ° C. and a thickness of 40 μm was obtained by a T-die method.

Comparative Example 5 A propylene-based resin film was obtained in the same manner as in Example 2 except that the cooling roll temperature was changed to 90 ° C.

Comparative Example 6 A propylene-based resin film was formed in the same manner as in Example 2 except that the amount of dibenzylidene sorbitol was changed to 0.08 parts by weight and the temperature of the cooling roll was changed to 15 ° C. However, a precipitate was deposited, and physical properties could not be measured.

The films obtained in Examples and Comparative Examples were subjected to evaluation tests for the following evaluation items by the following methods, and the results are shown in Table 1. (1) Transparency: Evaluated by measuring haze (JIS K7105). (2) Gloss: Evaluated by measuring gloss (JIS K7105). (3) Flexibility: Evaluated by measuring elastic modulus (JIS K7133).

[0030]

[Table 1]

[0031]

The structure of the method for producing a propylene-based resin film of the present invention is as described above. Therefore, a propylene-based resin film excellent in flexibility, glossiness, transparency and the like can be easily produced and obtained. A propylene-based resin film can be suitably used as a packaging film. Further, since it does not need to contain a plasticizer and is excellent in environmental properties, it can be suitably used for a soft vinyl chloride film.

Claims (2)

[Claims] 1. A resin composition comprising 100 to 100 parts by weight of a resin component comprising 97 to 10% by weight of a propylene resin and 3 to 90% by weight of a vinyl aromatic elastomer, and 0.005 to 0.1 part by weight of a crystal nucleating agent. Is formed at a cooling temperature of 30 to 70 ° C. by a T-die method or a downward water-cooled inflation method. 2. The method according to claim 1, wherein the vinyl aromatic elastomer is a hydrogenated styrene-butadiene random copolymer or a hydrogenated styrene-isoprene-styrene block copolymer.