JPH0661907B2 - 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]

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

However, since these resins generally lack ordinary heat-sealing properties, they are often used by laminating them with a resin having good heat-sealing properties such as a polyolefin resin. It is an excellent packaging material that combines features. 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, but a vinyl chloride resin is particularly preferable. In addition, the adhesiveness with vinylidene chloride resin is still insufficient, and 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 suitable amount of a plasticizer is usually added to these resins so as to give the film necessary properties such as flexibility and the like. A necessary amount of plasticizer is added, but it is particularly difficult to thermally bond a so-called soft vinyl chloride resin and a polyolefin resin containing the plasticizer, and this tendency tends to increase as the amount of plasticizer increases. large. 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, when the adhesion between the layers is insufficient, not only the oil resistance and heat resistance are adversely affected, but also the sealing strength is greatly affected, resulting in insufficient heat sealing 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 composition that strongly adheres thermally 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
50-wt% ethylene-vinyl acetate copolymer 1-99wt% and acrylic ester or methacrylic ester content 1
1 to 99 parts by weight of a resin composition consisting of 99 to 1% by weight of ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer of 30 to 30% by weight and 99 to 1 parts by weight of ethylene-α-olefin elastomer. Resin composition 1
An adhesive resin composition layer obtained by graft-modifying an unsaturated carboxylic acid or an anhydride thereof with the above-mentioned copolymer or ethylene-α-olefin elastomer in the presence of 0.001 to 0.5 part by weight of a radical generator with respect to 00 parts by weight. And a vinyl chloride resin layer or a vinylidene chloride resin layer.

The present invention will be described in detail below. The ethylene-vinyl acetate copolymer used in one of the resin compositions used for graft modification in the present invention (hereinafter, EV
The content of vinyl acetate (hereinafter abbreviated as A) is 3 to 50 wt%, preferably 10 to 35 wt%, and the melt flow rate (according to JIS K6760; the same applies hereinafter) is particularly limited. It is not limited to 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. This EVA
When the vinyl acetate content is less than 3% by weight, the adhesiveness is insufficient, and when it exceeds 50% by weight, the extrusion moldability is deteriorated and the melt flow rate is less than 0.5 g / 10 min.
Even if it exceeds g / 10 min, the extrusion moldability deteriorates.

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 not particularly limited, but 0.5 to 150 g / 10 min, preferably 1 to 50 g / 10 mi
n, and ethylene-vinyl acetate copolymer and ethylene-
In a resin composition comprising an acrylic acid ester copolymer or an ethylene-methacrylic acid ester copolymer, 99 to 1
wt%, preferably 7 to 10 wt% is used.

If the ester content in the ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer is less than 1 wt%, the adhesiveness will be insufficient, and if it exceeds 30 wt%, the extrusion moldability will decrease. Also, the melt flow rate is less than 0.5g / 10min or 150g / 10
Even if it exceeds 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 preferred.

This resin composition has a compounding ratio of EVA
If it exceeds 99 wt%, the adhesiveness with vinyl chloride resin or vinylidene chloride resin becomes insufficient, and if the ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer exceeds 99 wt%, the adhesiveness Will be insufficient.

The other component, the ethylene-α-olefin elastomer, is a copolymer elastomer of ethylene and an α-olefin having 3 or more carbon atoms, ethylene and an α-olefin having 3 or more carbon atoms, and a diene. And a copolymer elastomer thereof.

Examples of the ethylene-α-olefin copolymer elastomer having 3 or more carbon atoms include ethylene-propylene elastomer, ethylene-butene-1 elastomer and the like, wherein ethylene and α-olefin and diene having 3 or more carbon atoms are used. Examples of the copolymer elastomer are ethylene-propylene-dicyclopentadiene elastomer, ethylene-propylene-ethylidene norbornene elastomer, ethylene-propylene-1,4 hexadiene elastomer and the like.

These ethylene-α-olefin elastomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid ester copolymers and ethylene-methacrylic acid ester copolymers are used in the range that does not impair the characteristics in practice. Other resins, fillers, additives, etc. may be mixed.

The ethylene-α-olefin 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 either case, if the amount is 1 part by weight or less or 99 parts by weight or more, the adhesiveness is insufficient, and particularly the adhesiveness with the vinyl chloride resin containing 30 wt% or more of the plasticizer is insufficient.

An unsaturated carboxylic acid or its anhydride is added in the presence of 0.001 to 0.5 parts by weight, preferably 0.05 to 0.3 parts by weight, of a radical generator to 100 parts by weight of this resin composition,
This 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
When it exceeds the weight part, there is a concern that a gel may be generated due to crosslinking.

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) hexane-3, lauroyl peroxide and t-butylperoxybenzoate are preferably used, and of course, two or more kinds thereof may be combined.

Examples of the unsaturated carboxylic acid or its anhydride which is a monomer used 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. Acids, 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 modifying monomer and a radical generator to the above resin composition suspended or dissolved in an appropriate solvent and stirring the mixture, the resin composition and the graft modifying monomer and radical. Extruder, Banbury mixer, there is a method of melt-kneading using a kneader, etc. in advance, but the latter method is used in the case of graft modification with maleic acid, maleic anhydride, hymic acid anhydride, etc. It is preferred.

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. Any method such as coextrusion molding, extrusion coating, dry lamination and various heat welding methods can be adopted. Further, a desired laminate having different resin layers such as a polyolefin resin layer can be obtained. It is economical to obtain a multi-layer film, a multi-layer sheet, a multi-layer blow bottle, etc. having a desired shape by melt extrusion using separate extruders and coextrusion molding in which each layer is joined inside a circular die, T-die or immediately after extrusion. Preferred.

Molding is possible as long as 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.

[0022]

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) 12 g / 10 min, ethylene-vinyl acetate copolymer having vinyl acetate content of 15 wt% (hereinafter abbreviated as EVA) and melt flow rate (JIS K676).
0) 3.2 / 10 min, ethylene-methyl acrylate copolymer with a methyl acrylate content of 10 wt% (hereinafter abbreviated as EMA), melt flow rate (JIS K6758) 3.1 g / 10 min
And an ethylene-propylene elastomer having a propylene content of 28 mol% (hereinafter abbreviated as EPR) were mixed with a Henschel mixer at a ratio shown in Table 1, and di-t-butyl peroxide was added to 100 parts by weight of the above resin mixture. 0.0
After 14 parts by weight was added to evenly wet the pellet surface, 0.8 parts by weight of maleic acid was added to make a mixture with a Henschel mixer, which was melt-mixed and extruded at 200 ° C using a 40 mmφ extruder to obtain a graft-modified adhesive resin composition. I got a thing.

Then, this 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 45 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 pulling 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 Graft-modified adhesive resins were prepared in the same manner as in Examples 1 to 12 except that the EVA / EMA composition (A) and EPR were used in the proportions shown in Comparative Examples 1 to 5 in Table 1. A composition was obtained, and similarly, a two-layer film with PVC was prepared with 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.

[0026]

[Table 1]

Examples 13 to 21 Melt flow rate (JIS K6730) 20 g / 10 min, EVA with vinyl acetate content of 18 wt%, melt flow rate (JIS
K6760) 3g / 10min, Methylmethacrylate content 18wt
% Ethylene-methyl methacrylate copolymer (hereinafter,
Table 2 shows an ethylene-butene 1 elastomer (hereinafter abbreviated as EB) having an ethylene-α-olefin elastomer of butene-1 content of 10 mol% and a melt flow rate (JIS K6760) of 3.6 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 in 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.

[0029]

[Table 2]

[0030]

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%.
Resin composition 1 comprising 1 to 99 wt% of vinyl acetate copolymer and 99 to 1 wt% of ethylene-acrylic acid ester copolymer or ethylene-methacrylic acid ester copolymer having an acrylic acid ester or methacrylic acid ester content of 1 to 30 wt%
~ 99 parts by weight, ethylene-α olefin elastomer
An unsaturated carboxylic acid or an anhydride thereof is added to 100 parts by weight of a resin composition consisting of 99 to 1 parts by weight in the presence of 0.001 to 0.5 parts by weight of a radical generator, and the resin composition is graft-modified. A laminate comprising an adhesive resin composition layer and a vinyl chloride resin layer or a vinylidene chloride resin layer.