| 摘要 |
<p>1463403 Flexible polyurethane coatings BRITISH UNITED SHOE MACHINERY CO Ltd 19 March 1974 [20 March 1973] 12117/74 Heading C3R [Also in Divisions B1-B2] Flexible polyurethane coatings are prepared by mixing polyurethane-forming reagents under temperature conditions maintaining the reagents in liquid condition, the reagents comprising a polyisocyanate, a polyol and an amine, in relative proportions reactive to form an intermediate stage material, supplying the reacting mixture to a bank of intermediate stage material maintained under high rates of shear to blend freshly formed mixture with previously mixed material in the bank, and while continuing the shearing action, withdrawing portions of the blended material from the mass while the mass remains spreadable, spreading the withdrawn portions in a layer on a surface and then heating the layer to effect curing. The coating process is preferably a continuous one using the apparatus shown in Fig. 1. In this process a quasiprepolymer is placed in container 10 and an amine-containing component in container 12. Liquid is drawn from containers 10 and 12, rapidly mixed in a mixer 13 and supplied continuously through conduit 14 for deposition on a continuously moving surface 16. This surface is suitably a backing fabric which is drawn from supply roll 18, passes under a roll 20 and is laid down on a driven belt 22. The belt is driven by rolls 24 and passes over a supporting surface 26 in spaced relation to a spreader element viz. a knife member 28. Freshly mixed material is carried by surface 16 to knife member 28 where a rolling bank 32 of the reaction mixture is maintained. Knife member spreads the mixture as a uniform layer 34 on the surface 16. This layer is then carried through a heating chamber 36 for curing. In examples the surface 16 is a nylon fabric or a silicone treated release paper, in the latter case a napped fabric being coated by the transfer process.</p> |
