Terry M Lamb

US Patent:

46577904, Apr 14, 1987

Filed:

Jul 8, 1985

Appl. No.:

6/752868

Inventors:

Phillip L. Wing - Cohutta GA
James K. Jennings - Rocky Face GA
Terry L. Lamb - Ringgold GA

Assignee:

The Dow Chemical Company - Midland MI

International Classification:

B05D 302

US Classification:

4273741

Abstract:

A process for preparing a substrate backed with a polymer derived from an organic polyisocyanate, said process comprising the steps of (a) forming a precoat layer of a precoat reaction mixture comprising a substantially difunctional polyahl and a substantially difunctional organic polyisocyanate, (b) separately forming a capcoat layer of a capcoat reaction mixture comprising a polyahl and a polyisocyanate, (c) contacting said precoat layer with one surface of said substrate before said precoat layer is cured to a tack-free state, (d) contacting said capcoat layer with one surface of said precoat layer before at least one of said precoat layer and capcoat layer is cured to a tack-free state, (e) completing curing said capcoat and precoat layer, and (f) cooling the resulting polymer-backed substrate to a temperature less than about 35. degree. C. before any mechanical distortion thereof, wherein steps (a)-(f) are carried out under conditions such that mechanically induced stress in the substrate, precoat layer and capcoat layer is minimized. Another aspect of this invention is a polymer backed-substrate comprising (a) a substrate (b) attached to a surface of said substrate a precoat layer of a polymer formed by the reaction of a substantially difunctional polyahl and a substantially difunctional organic polyisocyanate, which precoat layer is overcoated with (c) a capcoat layer comprising a polymer formed by the reaction of a polyahl and an organic polyisocyanate.