JPH0661915B2 - Laminate - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laminate of a vinyl chloride resin and a vinylidene chloride resin, using a graft-modified resin composition having excellent adhesiveness to the resin.

[0002]

2. Description of the Related Art Vinyl chloride resins or vinylidene chloride resins are suitable as various packaging materials, especially food packaging materials, because they have excellent gas barrier properties, oil resistance and chemical resistance. is there.

However, since these resins are generally poor in ordinary heat-sealing property, they are often used by laminating with a resin having a good heat-sealing property, for example, a polyolefin resin, and this laminated body has the advantages of both. It becomes an excellent packaging material that combines both. However, it is essentially difficult to bond these resins to the polyolefin resin, and it is necessary to interpose an adhesive between the two materials.

As such an adhesive, various acid-grafted modified polyolefins have already been proposed and actually used as an adhesive layer in a laminate with a polyamide resin or an ethylene vinyl alcohol copolymer. In particular, vinyl chloride resins and Adhesiveness with vinylidene chloride resin is still insufficient, and the appearance of a resin having stronger adhesiveness is strongly demanded in the market.

When a vinyl chloride resin or vinylidene chloride resin is used as a packaging material, a suitable amount of a plasticizer is added to these resins in order to impart properties such as flexibility required as a film. It is particularly difficult to thermally bond a so-called soft vinyl chloride resin containing a polyolefin resin with a polyolefin resin, and this tendency becomes greater as the amount of the plasticizer increases, that is, the softer it becomes. It is considered that this is because the plasticizer bleeds on the surface of the vinyl chloride resin and the adhesion with the polyolefin is hindered by the plasticizer. As a matter of course, if the adhesion between the layers is insufficient, not only the oil resistance and heat resistance are adversely affected, but also the heat sealing strength is greatly affected, resulting in insufficient heat sealing, which makes it unusable for practical use.

[0006]

SUMMARY OF THE INVENTION It is therefore an object of the present invention to find a material having good adhesiveness with these resins having poor adhesiveness, and using this material to provide a laminate with a vinyl chloride resin or the like.

[0007]

Therefore, the present inventor has found that the vinyl chloride resin or
The present invention has been achieved as a result of extensive studies on an adhesive resin composition that strongly thermally adheres to a vinylidene chloride resin and a laminate using the same and having excellent barrier properties, oil resistance, and sealing properties. The gist of the present invention is that the vinyl acetate content is 3 to 5
1 to 99 parts by weight of an ethylene-vinyl acetate copolymer of 0 wt%, an acrylic acid ester content or a methacrylic acid ester content of 0.1 to 30 wt% and a maleic anhydride content of 0.
With respect to 100 parts by weight of a resin composition consisting of 99 to 1 part by weight of an ethylene-acrylic acid ester-maleic anhydride terpolymer or ethylene-methacrylic acid ester-maleic anhydride terpolymer of 05 to 20 wt%, An adhesive resin composition layer obtained by graft-modifying an unsaturated carboxylic acid or an anhydride thereof to the above-mentioned copolymer or terpolymer in the presence of 0.001 to 0.5 part by weight of a radical generator; And a vinyl resin layer or a vinylidene chloride resin layer.

The present invention will be described in detail below. In the present invention, the ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) as one resin used for graft modification has a vinyl acetate content (hereinafter abbreviated as vinyl acetate content) of 3 to 50 wt%, preferably 10 ~ 35 wt%, melt flow rate (according to JIS K6760, the same applies hereinafter)
As 0.5-300 g / 10 min, preferably 1-3
It is 0 g / 10 min, and 1 to 99 parts by weight, preferably 30 to 90 parts by weight, is used in the resin composition. This EVA
When the vinyl acetate content is less than 3 wt%, the adhesiveness is insufficient, and when it exceeds 50 wt%, the extrusion moldability decreases, and the melt flow rate is less than 0.5 g / 10 min or more than 300 g / 10 min. However, the extrusion moldability is reduced.

The ethylene-acrylic acid ester-maleic anhydride terpolymer or the ethylene-methacrylic acid ester-maleic anhydride terpolymer as the other resin used for graft modification has an acrylic acid ester content or Methacrylic acid ester content 0.1 to 30 wt%, preferably 5 to 20 wt%, maleic anhydride content 0.05 to 20 wt%
%, Preferably a terpolymer with 0.1 to 10 wt% of ethylene, and the melt flow rate is not particularly specified, but 0.5 to 150 g / 10 min, preferably 1 to 50 g / 10 min. The resin composition is used in an amount of 99 to 1 part by weight, preferably 30 to 10 parts by weight.
In this terpolymer, the ester content is 5 wt%
If the maleic anhydride content is less than 0.05 wt%, the adhesiveness is insufficient, and if the ester content exceeds 30 wt%, the adhesiveness decreases, and the maleic anhydride content is 2% or less.
If it exceeds 0 wt%, the extrusion moldability will deteriorate, and the melt flow rate will be less than 0.5 g / 10 min or 150 g / 1.
Even if it exceeds 0 min, the extrusion moldability deteriorates.

Examples of the acrylate ester include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like, and examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and the like. Especially, methyl acrylate, ethyl acrylate, and methyl methacrylate are preferable.

When the EVA exceeds 99 parts by weight in the compounding ratio, the adhesiveness with a vinyl chloride resin or vinylidene chloride resin deteriorates, and the terpolymer exceeds 99 parts by weight. Also lacks adhesiveness. Radical generator 0.001 to 100 parts by weight of this resin composition
In the presence of 0.5 part by weight, preferably 0.05 to 0.3 part by weight, unsaturated carboxylic acid or its anhydride is added to graft-modify the resin composition. If the amount of the radical generator is less than 0.001 part by weight, the adhesiveness will be insufficient, and
If the amount exceeds 5 parts by weight, gel due to cross-linking is generated and not only the commercial value is lowered but also the adhesiveness and the extrusion moldability are adversely affected.

Radical generators used for graft modification include dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane,
Organic peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexene-3, lauroyl peroxide and t-butylperoxybenzoate are preferably used, and a combination of two or more kinds may be used.

Examples of the unsaturated carboxylic acid or its anhydride used as a monomer for the graft modification include acrylic acid, maleic acid, fumaric acid, itaconic acid, hymic acid and their anhydrides, among which acrylic acid and maleic acid. , Maleic anhydride or hymic acid anhydride are preferred. Of course, these may be used in combination of two or more kinds. The graft modification is carried out by adding a monomer for graft modification and a radical generator to the above resin composition suspended or dissolved in a suitable solvent and stirring the mixture, the resin composition and the monomer and radical generator. There are methods such as pre-mixing and melt-kneading using an extruder, Banbury mixer, kneader, etc., but in the case of graft modification with maleic acid, maleic anhydride, hymic acid anhydride, etc., the latter method is preferred. Adopted. The amount of graft modification is not particularly limited, but may be 0.0001 to 3 parts by weight with respect to 100 parts by weight of the resin composition.

The thus obtained graft-modified adhesive resin composition of the present invention exhibits particularly excellent adhesiveness in a laminate for joining a vinyl chloride resin layer or a vinylidene chloride resin layer. As a method, for example, any method such as coextrusion molding, extrusion coating, dry laminating, various heat welding methods, etc. can be adopted, and a desired laminate having different resin layers including a polyolefin resin layer can be obtained. However, in particular, a method for obtaining a multilayer film, a multilayer sheet, a multilayer blow bottle, etc. having a desired shape by melt-extruding each resin by a separate extruder and joining each layer inside a circular die, a T-die or immediately after extrusion, that is, Coextrusion is economically advantageous. Molding is possible if the molding temperature is higher than the softening temperature of each resin and lower than the decomposition temperature. In the case of coextrusion molding, it is desirable that the melt viscosities of the resins forming the layers are not extremely different from the viewpoint of adhesiveness, moldability and physical properties.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. Examples 1-6, Comparative Examples 1-2 Melt flow rate 6.0 g / 10 min, vinyl acetate content 19
wt% ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA), melt flow rate 3.2 g / 10 min, methyl acrylate (hereinafter abbreviated as MA) content 3 wt%, maleic anhydride (hereinafter MAH) Abbreviated) content 0.4 wt%
Ethylene-MA-MAH terpolymer (hereinafter referred to as EMA
(Abbreviated as H) is mixed by a Henschel mixer in the ratio shown in Table 1, and 0.012 parts by weight of di-t-butyl peroxide is added to 100 parts by weight of the above resin mixture to evenly wet the pellet surface. And then maleic anhydride was reduced to 0.
7 parts by weight was added to make a uniform mixture with a Henschel mixer, and this was melt-mixed and extruded at 200 ° C. using a 40 mmφ extruder to obtain a graft-modified adhesive resin composition. Using a coextrusion film molding machine, the graft modified adhesive resin composition was subjected to a cylinder temperature of 180 ° C. and a die temperature of 180 ° C.
Then, a polyvinyl chloride resin (hereinafter abbreviated as PVC) containing 30% by weight of DOP (dioctyl phthalate) is used as a coextrusion film of two kinds and two layers (adhesive resin layer composition) at a cylinder temperature of 170 ° C. and a die temperature of 180 ° C. 20 μm thick, PVC layer 60 μm thick) were obtained. This co-extruded film is cut into a piece having a width of 15 mm and a length of 15 cm, and one end thereof is forcibly peeled off. A tensile speed of 100 mm / min, 180
The peel strength was measured under the condition of peeling once. The results are also shown in Table 1, but the peel strength was excellent in Examples 1 to 6 and weak in Comparative Examples 1 and 2 containing too much EVA or EMAH.

[0016]

[Table 1]

Examples 7-11, Comparative Examples 3-4 Melt flow rate 15 g / 10 min, vinyl acetate content 25 wt.
% EVA and melt flow rate 3.8 g / 10 min
Ethylene-EMA-M with an ethyl methacrylate (hereinafter abbreviated as EMA) content of 4.5 wt% and MAH of 1.3 wt%
AH terpolymer (hereinafter abbreviated as EEMAH) and Table 2
A graft-modified resin composition was obtained in the same manner as in Examples 1 to 6 except that the ratio shown in Table 1 was used, and the peel strength was measured by the same method. The results are shown in Table 2, and the peel strengths of Examples 7 to
11 was excellent, and it was weak in Comparative Examples 3 and 4 having too much EVA or EEMAH.

[0018]

[Table 2]

Examples 12 to 15 Melt flow rate 7 g / 10 min, methyl methacrylate (hereinafter abbreviated as MMA) content 8 wt%, MAH 2.9
wt% ethylene-MMA-MAH terpolymer (hereinafter,
A graft-modified resin was obtained in the same manner as in Examples 1 to 6 except that EMMAH was abbreviated as shown in Table 3, and the peel strength was measured by the same method. The results are shown in Table 3, and all of them showed excellent adhesion to PVC.

[0020]

[Table 3]

Claims (1)

[Claims] 1. An ethylene-vinyl acetate copolymer having a vinyl acetate content of 3 to 50 wt%, 1 to 99 parts by weight, an acrylic acid ester content or a methacrylic acid ester content of 0.1 to 10.
It comprises 99-1 parts by weight of ethylene-acrylic acid ester-maleic anhydride terpolymer or ethylene-methacrylic acid ester-maleic anhydride terpolymer of 30 wt% and maleic anhydride content of 0.05-20 wt%. With respect to 100 parts by weight of the resin composition, the radical generator 0.001 to 0.
An adhesive resin composition layer obtained by graft-modifying an unsaturated carboxylic acid or its anhydride in the presence of 5 parts by weight to the above-mentioned copolymer or terpolymer, a vinyl chloride resin layer or a vinylidene chloride resin A laminate consisting of layers.