Ternary adhesive systems containing a polyester polyol, an isocyanate-polyester-urethane, and a crosslinking agent which is a polyisocyanate

Claim 2

A ternary adhesive system consisting essentially of: A. a polyester polyol of adipic acid having a molecular weight MHD n of about 1,000-5,000 and soluble in methyl ethyl ketone or ethyl acetate to the extent of at least 65% by weight; B. an isocyanate-capped polyester-urethane formed from at least one diacid including adipic acid and at least one polyol having a molecular weight MHD n of about 500-4,000 which has been extended and capped with a diisocyanate in the --NCO/--OH ratio of 2/1-1.3/1 and is capable of forming a block copolymer with and thereby extending polyol A; and C. a polyisocyanate crosslinking agent C supplying 6-50% by weight in a mixture of B plus C.

Claim 3

An adhesive system of claim 1 wherein the polyester polyol A is a copolymer of at least one aromatic dicarboxylic acid and adipic acid with at least one polyol, ##EQU7## extending between 1.05/1 and 1.5/1, ##EQU8## extending between ∞ and 0.86/1, and ##EQU9## extending between 0 and about 0.8/1.

Claim 4

An adhesive system of claim 2 wherein the polyester polyol A is a copolyester of at least one phthalic acid and adipic acid.

Claim 5

An adhesive system of claim 2 wherein the polyester polyol A is a copolyester of at least one phthalic acid and adipic acid with ethylene glycol and trimethylol propane.

Claim 6

An adhesive system of claim 2 wherein the polyester-urethane B is formed from a hydroxyl-bearing polyester made from at least one polyol and at least one diacid including adipic acid wherein ##EQU10## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU11## is within the range 5/1-∞, ##EQU12## is within the range 0-0.8/1, and ##EQU13## is within the range 2/1-1.3/1.

Claim 7

An adhesive system of claim 5 wherein the hydroxyl-bearing polyester is a polyester of ethylene glycol, at least one phthalic acid and adipic acid.

Claim 8

A high-solids adhesive formed in situ wherein a polyester polyol of adipic acid A having a molecular weight MHD n of about 1,000-5,000 and soluble in methyl ethyl ketone or ethyl acetate to the extent of at least 65% by weight is chain-extended and thereby increased in molecular weight by reaction with an isocyanate-capped polyester-urethane B making a block copolymer therewith, said polyester-urethane B being formed from a hydroxyl-bearing polyester made from at least one polyol and at least one diacid including adipic acid and wherein ##EQU14## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU15## is within the range 5/1-∞, ##EQU16## is within the range 0-0.8/1, and ##EQU17## is within the range 2/1-1.3/1.

Claim 9

A high-solids adhesive formed in situ wherein a polyester polyol of adipic acid A having a molecular weight MHD n of about 1,000-5,000 and soluble in methyl ethyl ketone or ethyl acetate to the extent of at least 65% by weight is chain-extended and thereby increased in molecular weight by reaction with an isocyanate-capped polyester-urethane B making a block copolymer therewith, said polyester-urethane B being formed from a hydroxyl-bearing polyester made from at least one polyol and at least one diacid including adipic acid and wherein ##EQU14## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU15## is within the range 5/1-∞, ##EQU16## is within the range 0-0.8/1, and ##EQU17## is within the range 2/1-1.3/1.

Claim 10

An adhesive formed from: A. a hydroxyl-terminated polyester polyol of adipic acid having a molecular weight MHD n of about 1,000-5,000 and soluble in methyl ethyl ketone or ethyl acetate to the extent of at least 65% by weight; B. an isocyanate-capped polyester-urethane formed from a polyester polyol of adipic acid and at least one polyol having a molecular weight MHD n of about 500-4,000 and capable of forming a block copolymer with a thereby extending polyol A; and C. a polyisocyanate crosslinking agent, the equivalent ratio of --OH/--NCO being about 1/1 and B supplying at least 50-94% by weight of B plus C.

Claim 11

An adhesive formed from: A. a hydroxyl-terminated polyester polyol of adipic acid having a molecular weight MHD n of about 1,000-5,000 and soluble in methyl ethyl ketone or ethyl acetate to the extent of at least 65% by weight; B. an isocyanate-capped polyester-urethane formed from a polyester polyol of adipic acid and at least one polyol having a molecular weight MHD n of about 500-4,000 and capable of forming a block copolymer with a thereby extending polyol A; and C. a polyisocyanate crosslinking agent, the equivalent ratio of --OH/--NCO being about 1/1 and B supplying at least 50-94% by weight of B plus C.

Claim 12

An adhesive of claim 8 wherein the polyester A is a polyester of at least one phthalic acid and adipic acid.

Claim 13

An adhesive of claim 8 wherein the polyester A is a polyester of at least one phthalic acid and adipic acid with ethylene glycol and trimethylol propane.

Claim 14

An adhesive of claim 8 wherein the polyester-urethane B is formed from a hydroxyl-bearing polyester made from at least one diacid including adipic acid and at least one polyol wherein ##EQU18## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU19## is within the range 5/1-∞, ##EQU20## is within the range 0-0.8/1, and ##EQU21## is within the range 2/1-1.3/1.

Claim 15

An adhesive of claim 11 wherein the polyester-urethane B is formed from the polyester polyol ethylene glycol//terephthalic acid/isophthalic acid/adipic acid in the mole ratio of about 1.3//0.288/0.149/0.513 end-capped with toluene diisocyanate.

Claim 16

An adhesive of claim 12 wherein: A is a polyester of trimethylol propane/ethylene glycol//terephthalic acid/isophthalic acid/adipic acid of the mole ratio of about 0.2/0.954//0.128/0.213/0.659, the dry weight ratio A/B/C being about 57.24/33.67/9.09 and the dry weight ratio B/C being about 78.74/21.26.

Claim 17

An isocyanate-capped polyester urethane formed from a hydroxyl-bearing polyester made from at least one diacid including adipic acid and at least one polyol wherein ##EQU22## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU23## is within the range 5/1-∞, ##EQU24## is within the range 0-0.8/1, and ##EQU25## is within the range 2/1-1.3/1.

Claim 18

An isocyanate-capped polyester urethane formed from a hydroxyl-bearing polyester made from at least one diacid including adipic acid and at least one polyol wherein ##EQU22## is within the range 1.05/1-1.5/1 and the molecular weight MHD n=500-4,000, ##EQU23## is within the range 5/1-∞, ##EQU24## is within the range 0-0.8/1, and ##EQU25## is within the range 2/1-1.3/1.

Claim 19

The polyester-urethane of claim 14 formed from the polyester polyol ethylene glycol//terephthalic acid/isophthalic acid/adipic acid in the mole ratio of about 1.3//0.288/0.149/0.513 end-capped with toluene diisocyanate.

Claim 20

A flexible laminate wherein substrates are held together by an adhesive of claim 8.

Claim 21

A flexible laminate of claim 16 wherein the substrates are polyethylene and poly(ethylene terephthalate) films.