Stock material or miscellaneous articles – Composite – Of addition polymer from unsaturated monomers
Patent
1998-09-24
2000-01-18
Acquah, Samuel A.
Stock material or miscellaneous articles
Composite
Of addition polymer from unsaturated monomers
525 70, 525 71, 525 78, 525 86, 525 88, 525 95, 525241, 525437, 428212, 428412, 428483, 428355EN, B32B 2700
Patent
active
060156252
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to adhesive resin compositions and laminates using the compositions for their adhesive layers. More particularly, the invention relates to adhesive resin compositions free from lowering of adhesive strength even when contacted with hot water and to laminates using the compositions, said laminates having excellent gas barrier properties and capable of being subjected to retorting treatment.
BACKGROUND OF THE INVENTION
Polyester resins such as polyethylene terephthalate resin have excellent mechanical strength, rigidity, heat resistance, chemical resistance, oil resistance and transparency. Utilizing these excellent properties, the polyester resins are widely used for forming packaging materials such as films, sheets and containers. The polyester resins, however, have high permeability to gases such as oxygen, and therefore they cannot be used for forming packaging materials requiring high resistance to gas permeation, e.g., those for foods, medicaments and cosmetics.
Also, polycarbonate resins have excellent transparency, heat resistance and retention of scent, but they have high permeability to gases such as oxygen. Therefore, the polycarbonate resins cannot be used for forming packaging materials requiring high resistance to gas permeation, e.g., those for foods.
To improve the gas permeation resistance of the polyester resins and the polycarbonate resins, it has been proposed that a resin superior to the polyester resins and the polycarbonate resins in the gas permeation resistance, such as a saponified ethylene/vinyl acetate copolymer resin, is laminated on those resins. However, the adhesive strength between the polyester or polyester resin and the saponified ethylene/vinyl acetate copolymer resin is not always satisfactory, and this results in such a problem that partial separation takes place when the resins are laminated or the resulting laminate is used, whereby gas permeation resistance is decreased and appearance or mechanical strength of the final product is deteriorated.
To cope with the problem, Japanese Patent Laid-Open Publications No. 270155/1986 and No. 158043/1987 disclose laminates comprising a polycarbonate or polyester layer, an intermediate adhesive layer formed from an ethylene/.alpha.-olefin random copolymer having been graft-modified with an unsaturated carboxylic acid or its derivative and a saponified ethylene/vinyl acetate copolymer layer. The laminates not only show high gas permeation resistance but also have excellent adhesion properties at ordinary temperature, but when the laminates are subjected to high-temperature treatment such as hot filling treatment or retorting treatment, the adhesive strength may be decreased to cause separation of layers, resulting in lowering of gas permeation resistance.
Japanese Patent Laid-Open Publication No. 45445/1989 (correspond to U.S. Pat. No. 5,055,526, EP 315418B) applied by the present applicant discloses an adhesive resin composition capable of forming a laminate which is free from lowering of adhesive strength between the layers even after it is subjected to high-temperature treatment such as hot filling treatment or retorting treatment, and also discloses a laminate using the composition.
This adhesive resin composition comprises: 50 g/10 min, a density of 0.850 to 0.900 g/cM.sup.3, an ethylene content of 75 to 95% by mol and a crystallinity (measured by X-ray diffractometry) of less than 30%, in an amount of 95 to 50% by weight, 50 g/10 min and a vinyl acetate content of 5 to 40% by weight, in an amount of 5 to 50% by weight, and copolymer having a graft quantity of an unsaturated carboxylic acid or its derivative ranging from 0.05 to 15% by weight, a melt flow rate of 0.1 to 50 g/10 min, a density of 0.900 to 0.980 g/cm.sup.3 and a crystallinity (measured by X-ray diffractometry) of not less than 30%, in an amount of 1.0 to 30% by weight based on 100% by weight of the total amount of the components (a) and (b), rate (MFR) of 0.1 to 50 g/10 min and a crystallinity of less tha
REFERENCES:
patent: 4370388 (1983-01-01), Miro et al.
patent: 4548985 (1985-10-01), Yazaki et al.
patent: 5055526 (1991-10-01), Sato et al.
patent: 5089353 (1992-02-01), Negi et al.
patent: 5198494 (1993-03-01), Kawachi et al.
patent: 5225482 (1993-07-01), Nakagawa et al.
patent: 5250349 (1993-10-01), Nakagawa et al.
patent: 5346950 (1994-09-01), Negi et al.
Kawachi Hideshi
Morizono Kenichi
Okada Keiji
Shigemoto Hiromi
Acquah Samuel A.
Mitsui Chemicals Inc.
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