Method of making water repellent laminates
View Patent ↗The invention relates to a method of making a water repellent laminate including applying a hot melt moisture cure adhesive to a primary substrate and bonding the primary substrate with a secondary substrate that has been treated with a water repellent material prior to the lamination. The adhesive composition includes a hot melt moisture cure polyurethane prepolymer formed from a polyol component and a polyisocyanate component. The polyol component includes a first polyether polyol having a number average molecular weight of from about 500 to about 8,000, a first polyester polyol having a melting point of less than about 40° C. or a second polyether polyol having a molecular weight of from about 200 to about 1,000, and a crystalline polyester polyol having a melting point of from about 40° C. to about 120° C.
1. A method of making a water repellent laminate comprising a primary substrate having a first surface and a second surface and a secondary substrate having a bonding surface and an exposing surface, said bonding surface and exposing surface of said secondary substrate have been treated with a water repellent material, said method comprising:
a) applying a hot melt moisture cure polyurethane adhesive composition on said first surface of said primary substrate to form an adhesive bearing surface; and
b) bonding said adhesive bearing surface of said primary substrate with said bonding surface of said secondary substrate to form a laminate,
wherein said adhesive composition comprises a hot melt moisture cure polyurethane prepolymer having a weight average molecular weight of no greater than about 20,000 g/mole, said prepolymer being a reaction product of a polyol component and a polyisocyanate component, said polyol component comprising a first polyether polyol formed from at least one monomer chosen from ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,4-butylene oxide, or mixtures thereof; a first polyester polyol having a melting point of less than about 40° C.; and a crystalline polyester polyol having a melting point of from about 40° C. to about 120° C.
2. The method of claim 1 , wherein said polyol component further comprises an amorphous polyester polyol having a number average molecular weight of from about 500 g/mole to about 6,000 g/mole.
3. The method of claim 1 , wherein said first polyether polyol is a homopolymer of propylene oxide, or a copolymer of propylene oxide and ethylene oxide; said polyol having a number average molecular weight of from about 500 g/mole to about 4,000 g/mole.
4. The method of claim 1 , wherein said polyisocyanate component is diphenylmethane-4,4′-diisocyanate.
5. The method of claim 1 , wherein said adhesive composition has a viscosity of from about 2,000 cps to about 8,000 cps at 90° C.
6. The method of claim 1 , wherein said primary substrate is a thermoplastic film chosen from polytetrafluoroethylene (PTFE), thermoplastic polyurethane resin (TPU), polyester, or polypropylene.
7. The method of claim 1 , wherein said secondary substrate comprises woven or nonwoven fabric, cotton, polyester, or polyamide.
8. The method of claim 1 , wherein said laminate exhibits washing resistance.
9. A laminate made by the method of claim 1 .
10. A garment comprising the laminate of claim 9 .
11. The method of claim 1 , wherein said adhesive composition has a viscosity of less than about 12,000 cps at 90° C.