JP2000318102A - Gas-barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a film without using an adhesive layer by directly laminating a polyolefin on a gas-barrier resin layer comprising a copolymer between an olefinic macro-monomer and a vinyl monomer having a polar group. SOLUTION: In a film, a gas-barrier resin layer comprising a copolymer between an olefinic macro-monomer(OMM) and a vinyl monomer having a polar group (PBM) is directly laminated on a polyolefin film. OMM means a compound having a double bond radical-polymerizable with other monomers at one end of a polymer having an olefinic skeleton such as polyethylene, polypropylene, and an ethylene-butylene copolymer and exemplified by an alkyl group. PBM is a halogen-containing vinyl monomer such as vinyl chloride. In the copolymer between OMM and PBM, the weight ratio between OMM and PBM is preferably about 3/97-30/70.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a gas barrier film, and more particularly, to a gas barrier film on which a polyolefin is laminated.

[0002]

2. Description of the Related Art Water, moisture,
Various packaging forms are used to block air, oxygen and the like. As an index for comparing the protective performance of these packaging materials, gas barrier properties such as water vapor permeability and oxygen permeability are generally used.

Hitherto, polymers used as such a gas-barrier packaging polymer are roughly classified into a hydrophobic polymer and a hydrophilic polymer. Examples of the hydrophobic polymer include PET and polyvinylidene chloride. , Liquid crystal polyester, and the like, and the hydrophilic polymer is a saponified ethylene-vinyl acetate copolymer (hereinafter referred to as EV).
OH), polyamide 6, polyamide MXD6, PAN and the like.

[0004] In the case of a hydrophilic polymer, the gas barrier property changes depending on humidity, and particularly under high humidity, the gas barrier property is greatly reduced. Therefore, in the case of a hydrophilic polymer, it is customary to laminate a polyolefin or Al foil on the surface in order to prevent a decrease in gas barrier performance due to humidity.

However, since the adhesiveness between the hydrophilic polymer and the polyolefin film or Al foil is not sufficient, it is customary to provide an adhesive layer of a modified polyolefin or the like between the layers, for example, as disclosed in Japanese Patent Application Laid-Open No. 61-162439. Discloses the use of a modified polyolefin resin as an adhesive layer between an EVOH that is a hydrophilic polymer and a polyolefin. As the modified polyolefin layer generally used as the adhesive layer, a polyolefin modified with maleic anhydride or an epoxy group, for example, Admer (
Mitsui Chemicals, Inc.). In the case of a hydrophilic polymer,
As described above, an adhesive layer is indispensable, and there are problems such as difficulty in molding during production, an increase in steps, and an increase in cost.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a gas barrier film in which a hydrophilic polymer gas barrier resin layer and a polyolefin layer are directly laminated without using an adhesive layer. It is something to offer.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to achieve the above object, and a film of the present invention is a gas barrier resin comprising a copolymer of an olefin macromonomer and a vinyl monomer having a polar group. The above object is achieved by the layer being directly laminated on the polyolefin film.

[0008] The olefin macromonomer referred to in the present invention is polyethylene, polypropylene or ethylene.
-A compound having a radically polymerizable unsaturated double bond which can be polymerized at one end with another monomer of a polymer having an olefin skeleton such as a butylene copolymer. The double bond copolymerizable with another monomer means a radically polymerizable unsaturated double bond, and examples thereof include a vinyl group, an acroyl group, a methacryloyl group, and an allyl group.

A specific example of the olefin macromonomer is “KRATON LIQUID Polymer L-1253” (She
ll Chemical Company) and JP-A-5-19463.
A compound having a radically polymerizable double bond at the terminal of a polyolefin disclosed in the claims of JP-A-5-271720 and the claims of JP-A-6-329720;
Compounds having a radically polymerizable double bond at the terminal derived from the compounds disclosed in the claims of JP-A-19-193, claims of JP-A-6-32847, claims of JP-A-7-2928, etc. And the like.

The vinyl monomer having a polar group used in the present invention is a (meth) acrylate having an OH group, a vinyl monomer having a CONH group, a CN group or the like, a vinyl monomer having a halogen, and the like. Specifically, 2-hydroxyethyl (meth) acrylate,
Glucosylethyl methacrylate, N-methylacrylamide, N-isopropylacrylamide, (meth) acrylonitrile, vinylidene chloride, vinyl chloride and the like. These vinyl monomers having a polar group may be used alone or in combination of two or more. In addition, (meth) acrylic acid means acrylic acid and methacrylic acid.

The ratio of the olefin macromer to the polar group-containing vinyl monomer in the copolymer of the olefin macromonomer and the polar group-containing vinyl monomer in the present invention is usually from 1/99 to 60/40 by weight. And more preferably 3/97 to 30/70. When the amount of the olefin macromer is smaller than the above ratio, the adhesion to the polyolefin is poor, and when the amount is too large, the gas barrier property decreases. The molecular weight is not particularly limited,
It is usually 10,000 to 1,000,000, and more preferably 30,000 to 3
100,000.

In the copolymer of the olefin macromonomer and the vinyl monomer having a polar group referred to in the present invention, the side chain has 1 carbon atom within a range not to impair the object of the present invention.
Other monomers such as (meth) acrylates having from 12 to 12 alkyl groups and styrene monomers may be used in combination, and the amount is suitably from 1 to 80% by weight in the copolymer.

The copolymer of the olefin macromonomer of the present invention and a vinyl monomer having a polar group is added to EVO.
A hydrophilic gas barrier resin such as H, polyamide 6, polyamide MXD6, or PAN may be mixed. that time,
The ratio between the copolymer and the hydrophilic gas barrier resin is 10 /
90 to 90/10 is suitable. If the amount of the copolymer is less than the above ratio, the adhesion to the polyolefin will be reduced, and if it is too large, the gas barrier properties will be reduced.

In the present invention, the copolymer of an olefin macromonomer and a vinyl monomer having a polar group is polymerized by a polymerization method using a generally known thermal polymerization initiator or photopolymerization initiator. . The polymerization method is not particularly limited. However, since the compatibility between the olefin macromonomer and the monomer having a polar group may be insufficient, polymerization is usually performed by a solution polymerization method.

In the present invention, the method of obtaining a gas barrier film of the present invention by directly laminating a gas barrier resin layer comprising a copolymer of an olefin macromonomer and a vinyl monomer having a polar group on a polyolefin is not particularly limited. Commonly used methods such as a casting method, a heat laminating method, an extrusion coating method, and a co-extrusion method are exemplified. Usually, a highly productive extrusion method is used.

(Function) The gas barrier film of the present invention comprises:
It consists of a film made of a copolymer of an olefin macromonomer and a vinyl monomer having a polar group and a polyolefin film, and has a good gas barrier property because the copolymer contains a vinyl monomer having a polar group, In addition, because it contains an olefin macromonomer, it has good adhesion to olefins.

[0017]

The present invention will be described below with reference to several examples, but the present invention is not limited to these examples.

[Synthesis of Copolymer] (Copolymer 1) 20 parts by weight of acrylonitrile, ethylene
-Butylene macromonomer (Shell Chemical, L-125
3) 10 parts by weight, 70 parts by weight of isobonyl acrylate,
0.1 part by weight of a photopolymerization initiator (Irgacure 651, manufactured by Ciba Geigy) was dissolved in 100 parts by weight of toluene, and photopolymerization was carried out using a chemical lamp to obtain a toluene solution of copolymer 1.

(Copolymer 2) 10 parts by weight of ethylene-butylene macromonomer (manufactured by Shell Chemical Co., L-1253)
70 parts by weight of isobonyl acrylate and 0.1 part by weight of a photopolymerization initiator (Irgacure 651, manufactured by Ciba Geigy) are dissolved in 100 parts by weight of toluene, and photopolymerization is carried out using a chemical lamp, and a toluene solution of copolymer 2 is obtained. I got

Example 1 A toluene solution of the copolymer 1 was applied to a polyethylene film (MI = 3 g / 10 minutes) and dried to obtain a composite film. When the oxygen permeability of the obtained composite film was measured according to JIS K-7126, it was 10 cc / cm2 / 24 hrs (65% RH). The adhesion between the polyethylene film and the copolymer layer was good.

Example 2 A toluene solution of the copolymer 2 was dried to obtain a copolymer. 30 parts by weight of the obtained copolymer and 100 parts by weight of EVOH were melt-kneaded to obtain a mixture. The mixture was formed into a film by a hot press, and the film was laminated with a polyethylene film (MI = 3 g / 10 minutes) press to obtain a composite fill. When the oxygen permeability of the obtained film was measured according to JIS K-7126, it was 10 cc / cm2 / 24 hrs (65% RH). The adhesion between the polyethylene film and the copolymer layer was good.

Comparative Example 1 A gas barrier BAREX resin (# 1010, manufactured by Mitsui Chemicals) and polyethylene were co-extruded to obtain a composite film. The oxygen permeability of the obtained film was measured according to JIS K-7126 and found to be 10 cc / cm2 / 24 hrs (65% RH). However,
Adhesion with the polyethylene film was poor.

[0023]

According to the gas barrier film provided by the present invention, a polyolefin is directly laminated on a gas barrier resin layer composed of a copolymer of an olefin macromonomer and a vinyl monomer having a polar group. Is a copolymer of an olefin macromonomer and a vinyl compound having a polar group, so that not only gas barrier properties but also good adhesion to a polyolefin film are provided, so that a multilayer gas barrier film can be provided without using an adhesive layer. You.

Claims (1)

[Claims] 1. A gas barrier film comprising a polyolefin directly laminated on a gas barrier resin layer comprising a copolymer of an olefin macromonomer and a vinyl monomer having a polar group.