JP2000129004A - Soft polypropylene resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film excellent in heat seal processability, heat resistance and transparency by blending a random propylene-based copolymer and an ethylene/α-olefin copolymer with a specific density at a specific ratio and by maintaining its modulus in tension at a specific value. SOLUTION: A film contains 80-50 wt.% of a random propylene-based copolymer having an α-olefin content of 20 wt.% or less and a melt index of 3.0-15.0 g/10 min and 20-50 wt.% of an ethylene/3-10C α-olefin copolymer having a density of 0.86-0.89 g/cm3 and has a modulus in tension of 2,000-5,000 kg/cm2. The ethylene/α-olefin copolymer obtained by using a metallocene catalyst has a ratio of the weight average molecular weight/the number average molecular weight of 1-5 and a melt index of 1.0-5.0 g/10 min. An inner layer and outer layer of flexible propylene-based resin films and laminates are a blend of 80-50 wt.% of the random propylene-based copolymer and 20-50 wt.% of the ethylene/3-10C α-olefin copolymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soft polypropylene having good heat sealability, heat resistance, transparency and flexibility, which is used for bedding bags such as futons and sheets, clothing bags, sports goods bags and the like. It exists in the base resin film and the laminate.

[0002]

2. Description of the Related Art Conventionally, bags for bedding such as futons and sheets,
As clothing bags, sports goods bags, etc., products obtained by welding or heat sealing a soft polyvinyl chloride resin film are widely used in terms of transparency, flexibility, workability, texture, etc. ing. However, recently, due to environmental problems and problems such as bleeding out of the plasticizer compounded in the soft polyvinyl chloride resin film, polyethylene resin films, polypropylene resin films, etc. are used instead of the soft polyvinyl chloride resin film. The use of polyolefin-based resin films is expected. However, the polyolefin-based resin is non-polar, and has a problem that it is difficult to bond a film with a high-frequency welder. Although polyolefin resin films can be heat-sealed, polyethylene resins generally have poor abrasion resistance and heat resistance, and polypropylene resin films have excellent transparency, heat resistance, and rigidity compared to polyethylene resin films. However, there was a problem that flexibility was poor.

[0003]

SUMMARY OF THE INVENTION The present invention provides a polyolefin resin film and a laminate excellent in heat sealability, heat resistance, transparency, flexibility and fold resistance. .

[0004]

The gist of the present invention is that (a)
80 to 50% by weight of a random propylene-based copolymer,
(B) 20 to 50% by weight of an ethylene-α-olefin copolymer having a density of 0.86 to 0.89 g / cm ³ , and a tensile modulus of 2000 to 5000 kg / cm ^3.
soft polypropylene-based resin film and characterized in that it is a cm ^2, (a) random propylene copolymer and 80 to 50 wt%, and (b) Density 0.86 to 0.89
g / cm ³ , having an inner layer and an outer layer composed of a soft polypropylene resin film containing 20 to 50% by weight of an ethylene-α-olefin copolymer, and an intermediate layer containing a random propylene copolymer, And a laminate having a tensile elastic modulus of 2500 to 5000 kg / cm ² .

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The random propylene copolymer used in the flexible polypropylene resin film and laminate of the present invention is a random copolymer of propylene and a monomer copolymerizable therewith. Examples of the copolymerizable monomer include α-olefins such as ethylene, butene-1, pentene-1, hexene-1, octene-1, and 4-methylpentene-1. The proportion of the copolymerizable monomer in the random propylene-based copolymer is preferably less than 20% by weight. Further, the random propylene-based copolymer has a melt index (MI) of 3.0 to 15.0 g.
/ 10 minutes is preferable because of good moldability.

Further, the soft polypropylene resin of the present invention
In the inner and outer layers of the film and laminate, the density is
0.86-0.89 g / cm^ThreeIs ethylene and carbon
A copolymer with an α-olefin having 3 to 10 atoms (hereinafter, referred to as a copolymer)
"Ethylene-α-olefin copolymer")
You. The density of the ethylene-α-olefin copolymer is 0.8
6g / cm^ThreeIf it is less than this, there is no problem in mechanical properties and heat resistance.
0.89g / cm ^ThreeIf it exceeds, in terms of folding wrinkle resistance
It becomes a problem.

Further, the ethylene-α-olefin copolymer has a melt index (MI) of 1.0 to 5.0.
Those having 0 g / 10 min are preferable because of good moldability. In particular, the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by polymerization using a metallocene catalyst (hereinafter, referred to as “Mw”) / Mn ") is 1 to 5.
It is preferable to use an α-olefin copolymer because the product obtained after heat sealing does not have burrs or the like.

In the present invention, a metallocene catalyst (also referred to as a single-site catalyst or a Kaminski catalyst) is described in JP-A-3-163,088 and JP-A-7-118.
A catalyst comprising a metallocene transition metal complex and an organoaluminum compound as disclosed in JP-A-431, JP-A-7-148895, and the like, and may be used by being supported by an inorganic substance.

The metallocene-based transition metal complex includes, for example, a transition metal (titanium, zirconium, hafnium) selected from the group IVB, and a cyclopentadienyl group, a substituted cyclopentadienyl group, a dicyclopentadienyl group, a substituted dicyclopentadienyl group. A pentadienyl group, an indenyl group, a substituted indenyl group, a tetrahydroindenyl group, a substituted tetrahydroindenyl group, a fluorenyl group or a substituted fluorenyl group, which are coordinated with one or two ligands; Those in which two groups are crosslinked by a covalent bond are coordinated, and those having ligands such as a hydrogen atom, an oxygen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and an acetylacetonate group. can give.

Further, as the organoaluminum compound,
Alkyl aluminum and chain or cyclic aluminoxane are mentioned, as alkyl aluminum, triethyl aluminum, triisobutyl aluminum, dimethyl aluminum chloride, diethyl aluminum chloride, methyl aluminum dichloride, ethyl aluminum dichloride, dimethyl aluminum fluoride, diisobutyl aluminum hydride, Examples thereof include diethylaluminum hydride and ethylaluminum sesquichloride.The chain or cyclic aluminoxane can be produced by bringing the above-mentioned alkylaluminum into contact with water. Water, or water of crystallization of complex salt or water adsorbed by organic or inorganic compounds. It can be obtained by reacting Le aluminum.

Examples of the carrier for supporting the metallocene catalyst include silica gel, zeolite, and diatomaceous earth. The soft polypropylene resin film of the present invention and the inner layer and the outer layer of the laminate each have a random propylene copolymer of 80 to 50% by weight and a density of 0.86 to 0.5.
89 g / cm ³ , and 20 to 50% by weight of an ethylene-α-olefin copolymer. The blending ratio of the random propylene-based copolymer and the ethylene-α-olefin copolymer is random propylene-based copolymer / ethylene-α-olefin copolymer = 80 to 50 / by weight ratio.
It is preferably 20 to 50, particularly preferably 70 to 55/30 to 45. If the compounding ratio is more than 80/20, the flexibility or fold resistance of the film or the laminate is inferior, and if it is less than 50/50, the film is not firm and the feeling of use is not good.

The intermediate layer of the laminate of the present invention contains a random propylene-based copolymer. The content of the random propylene-based copolymer is preferably from 90 to 100% by weight. When the intermediate layer contains random propylene, the laminate becomes firm and workability when sewing with an industrial sewing machine is improved. Each layer of the soft polypropylene-based resin film and the laminate may contain other thermoplastic resins other than those described above as long as the object of the present invention is not impaired.

If necessary, an antioxidant, a lubricant,
Various additives such as an anti-blocking agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, a flame retardant, a colorant (pigment, dye) and an inorganic filler can be blended. Examples of the antioxidant include phenols such as 2,6-di-t-butyl-4-methylphenol and 2,4-dimethyl-6-t-butylphenol, amines such as phenyl-α-naphthylamine and diphenylamine, and phosphines. Phyto-based antioxidants are exemplified.

Examples of the lubricant include aliphatic amide lubricants such as erucamide, behenamide, oleamide, stearamide, and ethylenebisoleamide. As an anti-blocking agent, silica,
Zeolite and the like can be mentioned. Examples of the ultraviolet absorber include benzophenone-based, benzotriazole-based, salicylic acid-based, and phthalic acid-based ultraviolet absorbers.

Examples of the light stabilizer include hindered amine light stabilizers. Examples of the antistatic agent include cationic antistatic agents such as primary amine salts, tertiary amines, and pyridine derivatives, metal salts of higher fatty acids, alkylphenol sulfonates, fatty acid ethyl sulfonates, alkyl sulfonates, Examples include anionic antistatic agents such as phosphate ester salts, nonionic antistatic agents such as polyethylene glycol, and amphoteric antistatic agents such as carboxylic acid derivatives.

Examples of the flame retardant include antimony oxide. Examples of the coloring agent include carbon black, phthalocyanine, quinacridone, azo pigments, titanium oxide, and red iron oxide. Examples of the inorganic filler include glass fiber, asbestos, mica, aluminum silicate, calcium carbonate, and the like.

Various additives are blended with the random propylene-based copolymer and the ethylene-α-olefin copolymer as required, and the resulting mixture is kneaded with a Banbury mixer, a pressure kneader, or the like, and is then subjected to extrusion molding, injection molding, A film is prepared by a calender molding method or the like. Further, the laminate can be produced, for example, using a known multilayer co-extrusion molding machine.

The flexible polypropylene resin film of the present invention has a tensile modulus of 2000 to 5000 kg / cm ^2.
It is. If the tensile elasticity is less than 2000 kg / cm ² , the film tends to lose its stiffness and is 5,000 kg.
/ Cm ² , the flexibility of the film is poor. Further, the laminate has a tensile modulus of elasticity of 2500 to 5000 kg / cm.
² If the tensile elastic modulus is less than 2500 kg / cm ² , the laminate tends to have no stiffness and is 5,000 kg / cm ^2.
If it exceeds cm ² , the flexibility of the laminate will be poor.

The surface of the flexible polypropylene resin film or the laminate may be printed. In that case,
Preferably, the surface is corona treated. The thickness of the soft polypropylene-based resin film and the laminate is not particularly limited, but is usually 0.05 to 0.5 mm. The thickness of each layer of the laminate is the intermediate layer / (inner layer + outer layer) = 1/4 to 4 /
It is preferably set to 1. The obtained soft polypropylene-based resin film or laminate is heat-sealed at 120 to 130 ° C. to produce bedding bags such as futons and sheets, clothing bags, sporting goods bags, and the like.

[0020]

The embodiments of the present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. <Evaluation test method> (1) Heat sealability Using a heat seal tester manufactured by Tester Sangyo Co., Ltd., a sealing pressure of 2.0 kg / cm ² , a sealing time of 4 seconds, and changing the sealing temperature to heat the film or laminate. Evaluate sealability. ：: Adhesion, no change in shape of film or laminate △: Adhesion, but film or laminate undulates or shrinks ×: Adhesion not possible

(2) Tensile Modulus The tensile modulus of the film or the laminate was measured according to JIS K7113. (3) Folding wrinkle resistance 10 cm square film or laminate is folded in four,
After placing a 10 kg weight thereon for 1 hour, the film or laminate was taken out and spread, and the state of the fold after being left in a room at 23 ° C. for 24 hours was visually observed. ：: The fold is not noticeable △: The fold is noticeable ×: The fold is whitened

<Preparation of Film or Laminate> Examples 1 to 4 and Comparative Examples 1 to 6 Single-layer extrusion molding machines manufactured by Mitsubishi Heavy Industries, Ltd. were prepared using the compositions shown in Tables 1 and 2. Alternatively, a film or laminate having a thickness of 0.07 mm (layer ratio: inner layer / intermediate layer / outer layer = 3/2/3) was prepared by a multilayer extrusion molding machine manufactured by Mitsubishi Heavy Industries, Ltd. The film and the laminate were evaluated.
The results are shown in Tables 1 and 2.

[0023]

[Table 1]

[0024]

[Table 2]

[0025]

The soft polypropylene resin film and laminate of the present invention are excellent in heat sealability, heat resistance, transparency, flexibility and fold wrinkle resistance, and are suitable for bedding such as futons and sheets. It is suitably used for bags, clothing bags, sporting goods bags and the like.

Continuation of the front page F term (reference) 4F100 BA03 BA06 BA16 GB71 GB72 GB87 JJ03 JK02 JK07 JL12 JN01 YY00

Claims (4)

[Claims] 1. (a) random propylene-based copolymer 8
0 to 50% by weight, and (b) a density of 0.86 to 0.89 g
/ Cm ³ , ethylene and α- having 3 to 10 carbon atoms.
20 to 50% by weight of a copolymer with an olefin (hereinafter, referred to as "ethylene-α-olefin copolymer"), and a tensile modulus of 2000 to 5000 kg / cm.
^2. A soft polypropylene-based resin film, which is ² . 2. An ethylene-α-olefin copolymer,
The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by polymerization using a metallocene catalyst (hereinafter, referred to as “Mw”).
The flexible polypropylene-based resin film according to claim 1, wherein "Mw / Mn" is an ethylene-α-olefin copolymer of 1 to 5. 3. (a) random propylene copolymer 8
0 to 50% by weight, and (b) a density of 0.86 to 0.89 g
/ Cm ³ , ethylene-α-olefin copolymer 2
A laminate having an inner layer and an outer layer comprising a soft polypropylene-based resin film containing 0 to 50% by weight, an intermediate layer containing a random propylene-based copolymer, and having a tensile modulus of 2500 to 5000 kg / cm ^2. . 4. An ethylene-α-olefin copolymer,
Mw / M obtained by polymerization using a metallocene catalyst
The laminate according to claim 3, wherein n is an ethylene-α-olefin copolymer of 1 to 5.