JPH0767787B2 - 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 having excellent adhesiveness with vinyl chloride resins and vinylidene chloride resins.

[0002]

2. Description of the Related Art Vinyl chloride resins, vinylidene chloride resins, polyamide resins, ethylene vinyl alcohol copolymers, polyester resins, etc. are excellent in gas barrier properties and have good oil resistance and chemical resistance. Suitable for various packaging materials, especially food packaging materials.

[0003]

However, since these resins generally have poor sealing properties, they are often used by laminating with a resin having good sealing properties such as a polyolefin resin. It is an excellent packaging material that combines the features of. However, it is essentially difficult to bond these resins to the polyolefin resin, and it is essential to interpose an adhesive between the two materials. As such an adhesive, various acid-grafted modified polyolefins have already been proposed and actually used in the market, but the adhesiveness with vinyl chloride resin and vinylidene chloride resin is still insufficient. There is a strong demand for the appearance of a resin having stronger adhesiveness.

When a vinyl chloride resin or vinylidene chloride resin is used as a packaging material, a plasticizer is usually added to these resins in an appropriate amount to give the film the necessary properties such as flexibility. It is particularly difficult to thermally bond the so-called soft vinyl chloride resin and the polyolefin resin, and this tendency becomes greater as the amount of the plasticizer is increased, that is, when the resin becomes softer. It is considered that this is because the plasticizer bleeds on the surface of the resin and the adhesion with the polyolefin is hindered by the plasticizer. And, of course, if the adhesion is insufficient, not only the oil resistance and heat resistance are adversely affected, but also the seal strength is greatly affected and the seal becomes insufficient, so that it cannot be put to practical use.

[Necessity of rule] Required

[0005]

Therefore, the present inventor has developed an adhesive resin, a barrier property, an oil resistance, and a seal that strongly heat-adhere to a vinyl chloride resin or vinylidene chloride resin beyond the inhibition of adhesion by the plasticizer. The present invention has arrived at the present invention as a result of extensive studies on a laminate having excellent properties. 99-1 parts by weight of ethylene-acrylic acid ester copolymer having an ester content of 1 to 30 wt% or methacrylic acid ester content of 1
30 wt% ethylene-methacrylic acid ester copolymer 9
With respect to 100 parts by weight of the resin composition consisting of 9 to 1 parts by weight,
An unsaturated carboxylic acid or its anhydride is graft-modified in the presence of 0.001 to 0.5 part by weight of a radical generator to produce an adhesive resin layer, on which a vinyl chloride resin layer or vinylidene chloride resin layer is formed. It is a laminated body formed by laminating.

As a resin used for graft modification in the present invention, an ethylene-vinyl acetate copolymer (hereinafter referred to as EVA
Is a 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 shall apply hereinafter) is 0.5 to 300 g / 10 min, preferably 1 to 30 g / 10 min.
To 99 parts by weight, preferably 30 to 90 parts by weight.

If the vinyl acetate content is less than 3 wt%, the adhesiveness is insufficient, and if it exceeds 50 wt%, the extrusion moldability is deteriorated, and the melt flow rate is less than 0.5 g / 10 min or 300 g / 10 min. If it exceeds the limit, the extrusion moldability will decrease.

As the ethylene-acrylic acid ester copolymer or the ethylene-methacrylic acid ester copolymer, the acrylic acid ester content or the methacrylic acid ester content is 1 to 30 wt%, preferably 5 to 20 wt%. , The melt flow rate is 0.5 to 150 g /
It is 10 min, preferably 1 to 50 g / 10 min, and 99 to 1 part by weight, preferably 70 to 10 parts by weight, is used in the resin composition.

If the ester content is less than 1 wt%, the adhesiveness is insufficient, and if it exceeds 30 wt%, the extrusion moldability is deteriorated, and the melt flow rate is less than 0.5 g / 10 min or more than 150 g / 10 min. However, the extrusion moldability is reduced.

Examples of the acrylate ester include methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, butyl methacrylate, and the like. Methyl acrylate, ethyl acrylate and methyl methacrylate are preferred.

In this resin composition, if the EVA exceeds 99 parts by weight, the adhesiveness becomes insufficient, and the ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer exceeds 99 parts by weight. If it exceeds the range, the adhesiveness will be insufficient. With respect to 100 parts by weight of this resin composition, 0.001-0.5 parts by weight of the radical generator, preferably 0.1.
The unsaturated carboxylic acid or its anhydride is graft-modified in the presence of 05 to 0.3 parts by weight. If the amount of the radical generator is less than 0.001 part by weight, the adhesiveness will be insufficient and
If it exceeds 5 parts by weight, gelation due to crosslinking may occur.

As the radical generator, dicumyl peroxide, benzoyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-
Butylperoxy) hexane, 2,5-dimethyl-2,
Organic peroxides such as 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 used as a monomer for the graft modification include acrylic acid, maleic acid, fumaric acid, itaconic acid, hymic acid, and their anhydrides. Among them, acrylic acid and maleic acid are preferable. Acids, maleic anhydride or hymic acid anhydride are preferred. Also, two or more kinds may be combined. Graft modification is a method in which a graft monomer and a radical generator are added to the above resin composition suspended or dissolved in a suitable solvent and the mixture is heated and stirred, and the resin composition is premixed with the monomer and the radical generator. However, there is a method of melt-kneading using an extruder, a Banbury mixer, a kneader, etc.
When maleic anhydride, hymic acid anhydride or the like is used as a monomer for graft modification, the latter method is preferably adopted.

The adhesive resin obtained by the present invention exhibits particularly excellent adhesiveness in a laminate for joining a vinyl chloride resin layer or a vinylidene chloride resin layer, and the joining method is, for example, coextrusion molding. , Extrusion coating, dry lamination, various heat welding methods and the like can be adopted, and a desired laminate having different resin layers such as a polyolefin resin layer can be obtained. In particular, each resin is separately extruded. It is economically preferable to obtain a multi-layer film, a multi-layer sheet, a multi-layer blow bottle or the like having a desired shape by co-extrusion molding in which the respective layers are joined in a circular die, a T-die or the like by melting and extruding with a machine. .

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 viscosity of the resin forming each layer is not extremely different from the viewpoint of adhesiveness, moldability and physical properties.

[0016]

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples.

Examples 1 to 5 Melt flow rate 3.5 g / 10 min, vinyl acetate content 18 wt
% Ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA), melt flow rate 3.0 g / 10 min, methyl acrylate content 8 wt% ethylene-methyl acrylate copolymer (hereinafter abbreviated as EMA) Were mixed in a Henschel mixer in the proportions shown in Table 1 and mixed with 2,5 dimethyl-2,5
-Di- (t-butylperoxy) hexene-3 was added 0.012 parts by weight to 100 parts by weight of the above resin mixture to evenly wet the surface of the pellet, and then 0.7 parts by weight of maleic acid was added to the mixture to make Henschel. A mixture was made with a mixer, and this was melt-mixed and extruded at 200 ° C. using a 40 mmφ extruder to obtain a graft-modified adhesive resin.

Using a co-extrusion film forming apparatus, this graft-modified adhesive resin has a cylinder temperature of 180 ° C. and a die temperature of 80 ° C. and a polyvinyl chloride resin containing 35 wt% of DOP (dioctyl phthalate) (hereinafter abbreviated as PVC). 2) at a cylinder temperature of 170 ° C and a die temperature of 180 ° C.
A layer co-extruded film (adhesive resin layer 20 μ thick, PVC layer 60 μ thick) was obtained.

[0019]

[Table 1]

This co-extruded film has a width of 15 mm and a length of 1
It was cut into 5 cm, and one end thereof was forcibly peeled off, and the peeling strength was measured under the conditions of a peeling speed of 100 mm / min and 180 ° peeling using a Tenzilon type tensile tester. The results are also shown in Table 1, but the peel strength was excellent.

Comparative Examples 1-2 Graft modification in the same manner as in Examples 1-5 except that 100 parts by weight of the same EVA or the same EMA was used instead of the composition of EVA and EMA in Examples 1-5. A resin was obtained, 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 weak.

Examples 6 to 11, Comparative Examples 3 to 4 Melt flow rate 15 g / 10 min, vinyl acetate content 28 wt%
Of EVA and melt flow rate 3.1 g / 10 min, ethyl methacrylate content of 17 wt% ethylene-ethyl methacrylate copolymer (hereinafter abbreviated as EEMA) in the proportions shown in Table 2, and 2,5-dimethyl-2 as a peroxide. The peel strength was measured in the same manner as in Examples 1 to 5 except that 5,5 di- (t-butylperoxy) hexane was used.
The results are also shown in Table 2, and the peel strength was excellent in Examples 6 to 11 and weak in Comparative Examples 3 and 4.

[0023]

[Table 2]

Examples 12 to 15 Melt flow rate 6 g / 10 min, EVA with vinyl acetate content 28 wt% and melt flow rate 3.3 g / 10 min, methyl methacrylate (hereinafter abbreviated as MMA) content 6.5
Graft modification was carried out in the same manner as in Examples 1 to 5 except that a wt% ethylene-MMA copolymer (hereinafter abbreviated as EMMA) was used in the proportions shown in Table 3, and the same evaluation was performed. The results are shown in Table 3. All showed good adhesiveness.

[0025]

[Table 3]

[0026]

As described above, in the laminate of the present invention, the vinyl chloride resin or the vinylidene chloride resin and the adhesive resin are firmly adhered to each other, whereby the barrier property, the oil resistance and the sealing property are excellent. It is a thing.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C09J 151/06 JDH // B32B 27/32 C 8115-4F

Claims (1)

[Claims] 1. An ethylene-vinyl acetate copolymer having a vinyl acetate content of 3 to 50% by weight and 1 to 99 parts by weight, and an acrylic acid ester content of 1 to 30% by weight, an ethylene-acrylic acid ester copolymer or a methacrylic acid ester. Content 1
With respect to 100 parts by weight of the resin composition consisting of 99 to 1 parts by weight of the ethylene-methacrylic acid ester copolymer of 30% by weight, the unsaturated carboxylic acid or the unsaturated carboxylic acid or the same is added in the presence of 0.001 to 0.5 parts by weight of the radical generator. A laminate comprising an adhesive resin layer obtained by graft-modifying an anhydride and a vinyl chloride resin or vinylidene chloride resin layer.