Flexible laminates
AssigneeNational Starch and Chemical Investment Holding Corporation
InventorIrwin J. Davis
Life of this patent
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Abstract
Flexible laminates are prepared using a room temperature curable, water-borne laminating adhesive. The adhesive consists essentially of a copolymer emulsion of an alkyl acrylate, alkyl methacrylate, styrene or vinyl ester, or mixtures thereof, and an ethylenically unsaturated carboxylic acid, and optional selected comonomers, combined with an epoxy resin emulsion and a polyfunctional amine. The flexible laminates are characterized by rapid room temperature curing, high bond strength, superior heat resistance and chemical and water resistance.
Claims28
A process for the preparation of a flexible laminate comprising the steps of (a) coating a surface of a first lamina with a room temperature curable laminating adhesive, (b) heating said coated lamina to remove water and any solvent, (c) superimposing a second lamina over the coated surface of the first lamina and roller nipping the laminae at a temperature of from about 25.degree. to 150.degree. C., thereby bonding said first and second laminae and forming a flexible laminate, said laminating adhesive being in aqueous emulsion form and comprising,
- (A) an addition copolymer in aqueous emulsion form consisting of, on a solid basis, at least about 60% by weight of an alkyl acrylate, alkyl methacrylate, styrene or vinyl ester of a saturated monocarboxylic acid having 2 to 10 carbon atoms, or mixtures thereof, 1-10% by weight of an .alpha., .beta.-monoethylenically unsaturated carboxylic acid, from 0 to about 39% by weight of a copolymerizable comonomer selected from the group consisting of hydroxy alkyl acrylates, hydroxy alkyl methacrylates, .alpha.-methyl styrene, vinyl methyl ether, vinyl ethyl ether and monomers of the group ##STR2## wherein R.sub.1 is H or -CH.sub.3, R.sub.2 and R.sub.3 are H, alkyl (1-18C), -CH20H, or -CH20-alkyl (1-18C), and from 0 to about 15% by weight of a copolymerizable comonomer selected from the group consisting of acrylonitrile, methacrylonitrile, allyl carbamate and alkylolated allyl carbamate, said copolymer having a T.sub.g of +20.degree. to -50.degree. C.,
- (B) an epoxy resin aqueous emulsion, the solids of part (B) being present in an amount of about 5-50% by weight of the solids of part (A), and
- (C) a polyfunctional amine containing active hydrogen as a primary or secondary substituent present in an amount to provide 25-125% of the stoichiometric amount of amine based on total epoxy functionality, said amine reacting with said epoxy to effect curing thereof.
A laminating adhesive in aqueous emulsion from comprising:
- (A) an addition copolymer in aqueous emulsion form consisting of, on a solids basis,
- (a) at least about 60% by weight of an alkyl acrylate, alkyl methacrylate, styrene or vinyl ester of a saturated monocarboxylic acid having 2 to 10 carbon atoms, or mixtures thereof,
- (b) 1-10% by weight of an .alpha., .beta.-monoethylenically unsaturated carboxylic acid,
- (c) 0 to 39% by weight of a copolymerizable comonomer selected from the group consisting of hydroxy alkyl acrylates, hydroxy alkyl methacrylates, .alpha.-methyl styrene, vinyl methyl ether, vinyl ethyl ether and monomers of the group ##STR3## wherein R.sub.1 is H or -CH.sub.3, R.sub.2 and R.sub.3 are H, alkyl (1 -18C), -CH.sub.2 OH or -CH.sub.2 O-alkyl (1-18C) and
- (d) from 0 to about 15% by weight of a copolymerizable comonomer selected from the group consisting of acrylonitrile, methacrylonitrile, allyl carbamate and alkylolated allyl carbamate, said copolymer having a Tg of +20.degree. to -50.degree. C.,
- (B) an epoxy resin aqueous emulsion, the solids of part B being present in an amount of about 5-50% by weight of the solids of part A, and
- (C) a polyfunctional amine containing active hydrogen as a primary or secondary substitutent present in an amount to provide 25-125% of the stoichiometric amount of amine based on total epoxy functionality, said amine reacting with said epoxy to effect curing thereof.
In the process for the preparation of flexible laminates comprising applying an aqueous laminating adhesive to a solid substrate selected from the group consisting of paper, paperboard, metallic foils and metallized films, drying and recovering said solid substrate coated with an adhesive coating, the improvement consisting essentially of employing a laminating adhesive in aqueous emulsion form comprising:
- (A) an addition copolymer in aqueous emulsion from consisting of, on a solids basis,
- (a) at least about 60% by weight of an alkyl acrylate, alkyl methacrylate, styrene or vinyl ester of a saturated monocarboxylic acid having 2 to 10 carbon atoms, or mixtures thereof,
- (b) 1-10% by weight of an .alpha., .beta.-monoethylenically unsaturated carboxylic acid,
- (c) 0 to 395 by weight of a copolymerizable comonomer selected from the group consisting of hydroxy alkyl acrylates, hydroxy alkyl methacrylates, .alpha.-methyl styrene, vinyl methyl ether, vinyl ethyl ether and monomers of the group ##STR5## wherein R.sub.1 is H or -CH.sub.3, R.sub.2 and R.sub.3 are H, alkyl (1 -18C), -CH.sub.2 Oh or -CH.sub.2 O-alkyl (1-18C) and
- (d) from 0 to about 15% by weight of a copolymerizable comonomer selected from the group consisting of acrylonitrile, methacrylonitrile, allyl carbamate and alkylolated allyl carbamate, said copolymer having a Tg of +20.degree. to -50.degree. C.,
- (B) an epoxy resin aqueous emulsion, the solids of part B being present in an amount of about 5-50% by weight of the solids of part A, and
- (C) a polyfunctional amine containing active hydrogen as a primary or secondary substitutent present in an amount to provide 25-125% of the stoichiometric amount of amine based on total epoxy functionality, said amine reacting with said epoxy to effect curing thereof,
- said laminating adhesive being capable of laminating at temperatures of between 25.degree. and 150.degree. C.
Dependencies are inferred from the claim text.