| 摘要 |
1,122,119. Laminates. M. H. HECHT. 7 Dec., 1966, No. 54723/66. Heading B5N. A layer or coating of a thermoplastic film not inherently capable of being fused by a direct radio frequency field impressed across it is bonded to a substrate by positioning it in a field of frequency greater than a megacycle/sec. adjacent to a fibrous layer which contains 5 to 8% of water distributed throughout its mass. The method may be used to unite layers of paperboard, paper or leather using a thermoplastic film, or to bond a thermoplastic film to a layer of paper or paperboard which has been covered with a thermoplastic film or coating, or to bond together two thermoplastic films. In this latter case, a layer of a low dielectric loss factor material having a release surface and a fusing point substantially above that of the films is interposed between the films and the fibrous layer. Suitable thermoplastic films are polyethylene, polypropylene, polesters, which may be coated with a polyolefin, or a butadienestyrene copolymer. The paperboard surface contacting the film may be waxed, in which case the wax is melted from the surface and spread through the paperboard. Laminates comprising three layers of paperboard or leather having two intermediate polymeric films may be formed. |
