JPH0794509B2 - 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 using a graft-modified resin composition having excellent adhesion to vinyl chloride resins and vinylidene chloride resins.

[0002]

BACKGROUND OF THE INVENTION Vinyl chloride resins and 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. .

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 is 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 for the film. It is particularly difficult to thermally bond a so-called soft vinyl chloride-based resin containing a polyolefin resin with a polyolefin-based resin, and this tendency is as the amount of plasticizer increases.
The softer it is, the bigger it is. 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. Naturally, if the adhesion between layers is insufficient, oil resistance,
Not only the heat resistance is adversely affected, but also the heat seal strength is greatly affected, resulting in insufficient heat seal and no practical use.

[0006]

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

[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 that strongly adheres to a vinylidene chloride resin by heat and a laminate having excellent barrier properties, oil resistance and heat sealability. The gist of the present invention is 1-99 wt% of ethylene-vinyl acetate copolymer having a vinyl acetate content of 3-50 wt% and ethylene-acrylic acid ester or methacrylic acid ester content of 0.1-30 wt% and maleic anhydride content of 0.05-20 wt%. Acrylic acid ester-maleic anhydride terpolymer or ethylene-methacrylic acid ester-maleic anhydride terpolymer 99 to 1 wt% resin composition 1 to 99 parts by weight, and ethylene-α-olefin Radical generator to 100 parts by weight of resin composition consisting of 99 to 1 parts by weight of elastomer
Unsaturated carboxylic acid or its anhydride in the presence of 0.001 to 0.5 parts by weight of the copolymer, terpolymer or ethylene-
A laminate comprising an adhesive resin composition layer graft-modified with an α-olefin elastomer and a vinyl chloride resin layer or a vinylidene chloride resin layer.

The present invention will be described in detail below. In the present invention, an ethylene / vinyl acetate copolymer (hereinafter abbreviated as EVA) as a resin used for graft modification is
Vinyl acetate content (hereinafter abbreviated as vinyl acetate content) is 3 to 50 wt.
%, Preferably 10 to 35 wt%, and the melt flow rate (according to JIS K6760; the same applies hereinafter) is not particularly limited, but 0.5 to 300 g / 10 min, preferably 1 to 30
g / 10 min, and 1 to 99 wt%, preferably 30 to 90 wt% is used in the resin composition. In this EVA, when the vinyl acetate content is less than 3 wt%, the adhesiveness is insufficient, and 50
When it exceeds wt%, the extrusion moldability is deteriorated, and even when the melt flow rate is less than 0.5 g / 10 min or exceeds 300 g / 10 min, the extrusion moldability is deteriorated.

The ethylene / acrylic acid ester / maleic anhydride terpolymer or the ethylene / methacrylic acid ester / maleic anhydride terpolymer has an acrylic acid ester content or a methacrylic acid ester content of 0.1 to 30.
wt% preferably 5-20 wt%, maleic anhydride content 0.05-
It is a terpolymer with ethylene containing 20 wt%, preferably 0.1 to 10 wt%, and the melt flow rate is not particularly limited, but 0.5 to 150 g / 10 min, preferably 1
~ 50g / 10min, 99 ~ 1wt% in resin composition
Preferably, 30 to 10 wt% is used. In this terpolymer, if the ester content is less than 5 wt% and the maleic anhydride content is less than 0.05 wt%, the adhesiveness is insufficient,
If the ester content exceeds 30 wt%, the adhesiveness will decrease,
If the maleic anhydride content exceeds 20 wt%, the extrusion moldability will deteriorate, and if the melt flow rate is less than 0.5 g / 10 min or more than 150 g / 10 min, the extrusion moldability will also deteriorate.

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.

This resin composition has a compounding ratio of EVA
If it exceeds 99 wt%, the adhesiveness with vinyl chloride resin or vinylidene chloride resin is reduced, and the terpolymer is 99% or less.
Even if it exceeds wt%, the adhesiveness is insufficient.

The other ethylene-α olefin elastomer is ethylene and α having 3 or more carbon atoms.
-Copolymer elastomers with olefins and copolymer elastomers with ethylene and α-olefins and diene having 3 or more carbon atoms. Examples of the ethylene and α-olefin copolymer elastomer having 3 or more carbon atoms include ethylene-propylene elastomer and ethylene-butene-1 elastomer, and the copolymer elastomer of ethylene and α-olefin having 3 or more carbon atoms and diene. as,
Examples thereof include ethylene-propylene-dicyclopentadiene elastomer, ethylene-propylene-ethylidene norbornene elastomer, and ethylene-propylene-1,4 hexadiene elastomer. These ethylene-α olefin-based elastomers, ethylene vinyl acetate copolymers, ethylene-acrylic acid ester copolymers and ethylene-methacrylic acid ester copolymers are other resins within a range that does not impair the characteristics in practice. Fillers, additives and the like may be mixed.

The ethylene-α-olefin-based elastomer is graft-modified in the form of a composition with the ethylene vinyl acetate copolymer / ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer resin composition. The ratio is 1 to 99 parts by weight of the former and 99 to 1 parts by weight of the latter. In any case, if it is less than 1 part by weight or more than 99 parts by weight, the adhesiveness is insufficient,
In particular, the adhesiveness with a vinyl chloride resin containing a plasticizer amount of 30 wt% or more becomes insufficient.

An unsaturated carboxylic acid or its anhydride is added in the presence of 0.001 to 0.5 part by weight, preferably 0.05 to 0.3 part by weight, of a radical generator to 100 parts by weight of this resin composition,
The resin composition is graft-modified. If the radical generator is less than 0.001 part by weight, the adhesiveness will be insufficient and 0.5
If the amount is more than parts by weight, gel is generated due to cross-linking, which not only reduces the commercial value but also adversely affects the adhesiveness and the extrusion moldability.

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 two or more kinds may be combined. .

Examples of the unsaturated carboxylic acid or its anhydride which is a monomer used for 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 graft monomer and a radical generator to the above resin composition suspended or dissolved in a suitable solvent and stirring the mixture by heating, the resin composition, the monomer and the 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 it is based on 100 parts by weight of the resin composition.
It may be 0.0001 to 3 parts by weight.

The graft-modified resin composition thus obtained of the present invention exhibits particularly excellent adhesiveness in a laminate for joining a vinyl chloride resin layer or a vinylidene chloride resin layer. Examples of the joining method include: Any method such as coextrusion molding, extrusion coating, dry lamination, and various heat welding methods can be adopted, and a desired laminate in which different resin layers including a polyolefin resin layer are laminated can be obtained. Are melt-extruded by separate extruders and the layers are joined inside a circular die, T-die or immediately after extrusion to obtain a multilayer film, a multilayer sheet, a multilayer blow bottle, etc. having a desired shape, that is, coextrusion molding is economical. It is advantageous in terms of physical properties.

Molding is possible if the molding temperature is not lower than the softening temperature of each resin and not higher 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.

[0020]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. Examples 1 to 12 Melt flow rate (JIS K6730) 3.8 g / 10 min, ethylene-vinyl acetate copolymer having vinyl acetate content of 18.6 wt% (hereinafter abbreviated as EVA) and melt flow rate (JIS
K6760) 6.0 g / 10 min, ethyl acrylate (hereinafter E
A maleic anhydride (hereinafter abbreviated as MA) content 6 wt%
Ethylene-EA-MAH terpolymer (abbreviated as H) (hereinafter abbreviated as EEMAH) and melt flow rate (JIS K6758) 3.1 g / 10 min, ethylene-propylene having a propylene content of 28 mol% Elastomer (hereinafter abbreviated as EPR) was mixed with a Henschel mixer at a ratio shown in Table 1, and 0.014 parts by weight of di-t-butyl peroxide was added to 100 parts by weight of the above resin mixture to make the pellet surface uniform. After wetting, add 0.8 parts by weight of MAH and make a mixture with a Henschel mixer.
Using a extruder, melt-mixing extrusion was performed at 200 ° C. to obtain a graft-modified adhesive resin composition.

Next, the graft-modified adhesive resin composition was heated at a cylinder temperature of 180 using a coextrusion film forming apparatus.
At a die temperature of 185 ° C and a polyvinyl chloride resin (hereinafter abbreviated as PVC) containing 48 wt% of DOP (dioctyl phthalate) at a cylinder temperature of 170 ° C and a die temperature of 180 ° C.
Layer coextrusion film (adhesive resin composition layer 30 μm thick, P
A VC layer (50 μm thick) was obtained.

This coextrusion film was cut into a piece having a width of 15 mm and a length of 15 cm, and one end thereof was forcibly peeled off, and the peeling strength was measured using a Tensilon type tensile tester under the conditions of a peeling speed of 100 mm / min and a peeling of 180 degrees. The results are also shown in Table 1, but in all cases, the peel strength was high.

Comparative Examples 1 to 5 Examples 1 to 12 except that the EVA / EEMAH composition (A) and EPR were used in the proportions shown in Comparative Examples 1 to 5 in Table 1.
A graft-modified adhesive resin composition was obtained in the same manner as above, and a two-layer film with PVC was similarly prepared by a coextrusion molding machine and the peel strength was measured. The results are also shown in Table 1, but the peel strength was low in all cases.

[0024]

[Table 1]

Examples 13 to 21 Melt flow rate (JIS K6730) 15 g / 10 min, EVA with vinyl acetate content 25 wt%, and melt flow rate (JIS K6760) 5.8 g / 10 min, methyl acrylate (hereinafter abbreviated as MMA) ) Content 9wt%, MAH content 1.3wt%
Ethylene-MMA-MAH terpolymer (hereinafter, EM
MAH) and ethylene-butene 1 elastomer (hereinafter abbreviated as EB) having an ethylene-α-olefin elastomer of 15 mol% butene-1 content and a melt flow rate (JIS K6760) of 3.9 g / 10 min. Examples 1 to 12 except that they were used in the proportions shown in Examples 13 to 21 of
A graft-modified adhesive resin composition was obtained in the same manner as above, and PVC and a two-layer film were similarly prepared with a coextrusion molding machine and the peel strength was measured. The results are also shown in Table 2, but the peel strength was high in all cases.

Comparative Examples 6 to 9 Graft-modified adhesive resin compositions were obtained from the resin compositions of Comparative Examples 6 to 9 shown in Table 2 in the same manner as Comparative Examples 1 to 5, and a two-layer film with PVC was prepared by the same method. The interlaminar peel strength was measured. The results are also shown in Table 2, but the peel strength was lower than in Examples 13 to 21.

[0027]

[Table 2]

[0028]

The laminate comprising the graft-modified adhesive resin composition layer and the vinyl chloride resin layer or the vinylidene chloride resin layer obtained in the present invention has a strong peel strength between layers and exhibits excellent adhesiveness. .

Claims (1)

[Claims] 1. Ethylene having a vinyl acetate content of 3 to 50 wt%.
Ethylene-acrylic acid ester-maleic anhydride terpolymer or 1-99 wt% vinyl acetate copolymer and 0.1 to 30 wt% acrylic acid ester or methacrylic acid ester content and 0.05 to 20 wt% maleic anhydride content
Methacrylic acid ester-maleic anhydride terpolymer 99
1 to 99 parts by weight of a resin composition consisting of 1 to 1 wt% and 100 parts by weight of a resin composition consisting of 99 to 1 parts by weight of an ethylene-α-olefin elastomer, a radical generator 0.001 to
An unsaturated carboxylic acid or its anhydride is added in the presence of 0.5 part by weight, and an adhesive resin composition layer obtained by graft-modifying the resin composition and a vinyl chloride resin layer or a vinylidene chloride resin layer are formed. Laminate.