Process for the production of laminates

摘要

1,081,506. Laminates. HENKEL & CIE G.m.b.H. March 24, 1966 [March 25, 1965], No. 12941/66. Heading B5N. Laminates bonded with a melamine resin are produced by impregnating papers with an aqueous solution of a melamine formaldehyde pre-condensate in which the molar ratio of melamine to formaldehyde is 1: 1À5 to 1: 2À5 containing in addition 2 to 20% of an acetate group containing polyvinyl alcohol having a saponification number of 50 to 250 and 1 to 10% of a C 2 to C 6 polyhydric alcohol based on the weight of dry melamine-formaldehyde precondensate, drying, and then pressing them on to a substrate material. The lower alcohol is preferably ethylene glycol but may also be propanediol, butanediol, glycerol, di- or triethylene glycol, mannitol or sorbitol. Drying preferably takes place at 80‹ to 150‹ C., and the paper is suitably pressed on to the substrate, which may be chipboard, plywood, massive wood or laminates loaded with other resins at 120‹ to 200‹ C., at pressures of 6 to 13 kg./cm.2 for 1 to 15 minutes.