| 摘要 |
<p>1282667 Adhesive-coated polyvinyl fluoride films DYNAMIT NOBEL AG 14 Sept 1970 [15 Sept 1969] 43881/70 Heading B2E [Also in Divisions B5 and C3] An adhesive-coated cast polyvinyl fluoride film capable of being bonded to a substrate (see Division B5) is produced by incompletely gelling a film of a solution or dispersion of polyvinyl fluoride deposited on a support by removal of solvent or dispersant from the solution or dispersion to a residual content of 0.4-0.8% by weight, coating the film containing the residual content of solvent or dispersant on one side with a layer of adhesive, and drying the coated film by evaporating of all solvent and/or dispersant present, the adhesive being stable at the temperature at which the evaporation takes place. The adhesive can be applied in the form of a solution by brushing or spraying. Suitable adhesives are polyurethanes. As shown in Figure 1, a pigmented and deaerated polyvinyl fluoride dispersion is applied by means of reverse-roll coater 2 to a continuous metal belt 9 driven from motor 1 by way of a tensioning drum 10 and supporting rollers 11. The coated belt was passed through an air-heated pre-gelling duct 3 at 260‹C., then through a short cooling zone and a mixture of a solution of polyester containing urethane groups and a solution of the reaction product of 1 mol trimethylol propane and 3 mols of tolylene diisocyanate and propylene carbonate applied by distributor 4. The film on the metal belt then travelled through second gelling duct 5 in which it was contacted with heated air at 250‹C, then through air-cooled tar 6 and over cooling roller 7. In the Examples the cast film is bonded directly to polyvinyl chloride, wood or vulcanised fibre by pressure. The film is also bonded to a polyvinyl chloride panel coated with a solution of a copolymer of vinyl chloride, vinyl acetate and maleic acid.</p> |
