| 摘要 |
of the disclosure A coating binder composition, composed of 60 80% by weight of hydroxyl group-containing copolymers as binder A) and 20 - 40% by weight of an organic polyisocyanate B). Component A) has n hydroxyl group content of 3.6 to 6.5% by weight and was prepared in solvents which do not contain active hydrogen atoms in the presence of the mixture of a diacyl-peroxide or perestsr and an alkyl hypoperoxide or dialkyl peroxide as polymerisation initiators from a) glycidyl esters dissolved in solvents by slow uniform addition of a mixture of b) hydroxyl ethyl acrylate and/or -methacrylate, c) acrylic acid, d1) styrene and d2) methylmethacrylate. The components a) to d2) and components A) and B) have each a total of up to 100% by weight. The coating compositions according to the invention have the following advantages compared with those of copolymers: better resistance to weathering in the climate of Florida. When clear lacquers or pigmented lacquers are applied by spraying to sheet steel, dry film layers of high thickness of 70 to 80 .mu.m which do not exhibit crater formation and blistering, are obtained after a brief period of exposure to air and subsequent stoving. The coating composition can be employed on substrates of the most diverse kind, for example porous or non-porous substrates, such as textile non-wovens, leather or plastics. The coatings obtained are of high gloss, pore-free, elastic, have a very hard surface, are resistant to solvents and display, in addition, an outstanding resistance to weathering and resistance to yellowing. A further subject of the invention is an applied coating composition, which is touched up with a coating agent composition which binder comprises a mixture of component A) and a thermoplastic acrylic copolymer. |
