Solventless laminating adhesive for flexible packaging laminations and laminated structures made with the adhesive

Abstract

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.

What is claimed is: 
     
         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.