SOLVENTLESS LAMINATING ADHESIVE FOR FLEXIBLE PACKAGING LAMINATIONS AND LAMINATED STRUCTURES MADE WITH THE ADHESIVE
Two-component solventless adhesive compositions for lamination applications and laminated structures, including flexible laminated packaging, comprising at least two substrates, including structures comprising reverse printed ink films and/or metallized films. The adhesive comprises a prepolymer having one or more oligomers with a relatively high molecular weight.
1 . A two-component solventless adhesive comprising a prepolymer having
a) a first oligomer with a molecular weight of at least about 3,500 g/mole; and
b) an isocyanate.
2 . The adhesive of claim 1 wherein the oligomer is a polyol selected from the group consisting of polyoxypropylene glycol, polyoxyethylene glycol, copolymers of ethylene oxide and propylene oxide and polyester polyols.
3 . The adhesive of claim 1 wherein the first oligomer is in an amount of at least about 20% by weight of the prepolymer.
4 . The adhesive of claim 1 wherein the isocyanate is selected from the group consisting of hexamethylene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, allophonate modified diphenylmethane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, bitolylene diisocyanate, cyclohexane diisocyanate, bis-(isocyanatomethyl)cyclohexane, dicyclohexylmethane diisocyanate, dimer acid diisocyanate, trimethyl hexamethylene diisocyanate, lysine diisocyanate and its methyl ester, isophorone diisocyanate, methyl cyclohexane diisocyanate, 1,5-napthalene diisocyanate, xylylene diisocyanate and methyl derivatives thereof, xylene diisocyanate and methyl derivatives thereof, polymethylene polyphenyl isocyanates, chlorophenylene-2,4-diisocyanate, polyphenylene diisocyanates, isophorone diisocyanate, hydrogenated methylene diphenyl isocyanate, tetramethyl xylene diisocyanate, hexamethylene diisocyanate, trimer of isophorone diisocyanate, trimer of hexamethylene diisocyanate, biuret of hexamethylene diisocyanate and combinations thereof.
5 . The adhesive of claim 1 comprising a curative having an isocyanate reactive component selected from the group consisting of polyhydroxyls, polythiols, polyamines and combinations thereof.
6 . A two-component solventless adhesive comprising a prepolymer having
a) a first oligomer with a molecular weight of about 2,000 g/mole to about 5,000 g/mole a second oligomer having a molecular weight of about 5,500 g/mole to about 10,000 g/mole; and
b) an isocyanate.
7 . A process for making a laminated structure comprising the steps of
a) providing a first substrate and a second substrate each having an upper surface and a lower surface wherein at least one of the first substrate or second substrate is selected from the group consisting of substrate having water-base ink, a substrate having a metallized film and combinations thereof;
b) providing the adhesive of claim 1 and applying the adhesive to at least one surface of at least one of the first substrate or second substrate; and
c) bonding the first substrate to the second substrate to form a laminated structure.
8 . The process of claim 7 wherein the adhesive is applied by a method selected from the group consisting of roll coating, gravure, and offset gravure.
9 . The process of claim 7 wherein the first substrate is a reverse printed film comprising a water-base adhesive and the second substrate comprises a metallized film.
10 . The process of claim 7 wherein the first substrate comprises a metallized film and the second substrate is a reverse printed film comprising a water-base ink.
11 . The process of claim 7 wherein at least one of the first substrate or second substrate is surface treated.