| 摘要 |
<p>1417502 Coated polycarbonate substrates BAYCHEM CORP 19 April 1973 [19 April 1972] 18991/73 Heading B2E [Also in Division C3] Polycarbonate articles or substrates are provided with a coating which comprises (1) 5-62% (by weight) of a linear diol, (2) 8-35% of a thermosetting resin containing about 10% (by weight of the resin) of units of an ethylenically unsaturated carboxylic acid or anhydride, 4-10% of units of a hydroxyalkyl ester of anα, #-ethylenically unsaturated carboxylic acid, and a balance to 100% of units of at least one alkyl ester of anα, #-ethylenically unsaturated carboxylic acid, and (3) 17-87% of a crosslinking agent for the thermosetting resin. The diol (1) is preferably a linear polyester having an OH equivalent weight of from 50-600, e.g. a polycaprolactone. Preferred as resin (2) is a copolymer of ethyl acrylate, methyl methacrylate, acrylic acid and 3-hydroxy propyl methacrylate. The crosslinking component (3) is preferably hexamethoxy methyl melamine, used together with an acid and/or salt thereof with a weak base as curing catalyst, e.g. p-toluene sulphonic acid or its N-ethyl morpholine salt. The coating is preferably applied from solution in an organic solvent, a particularly useful solvent being a mixture of toluene and ethylene glycol monoethyl ether and, optionally also, n-butanol. Optional additives which may be used include UV stabilisers, e.g. the diethyl ester of p-methoxybenzylidene-malonic acid, silicone flow control agents, pigments, antioxidants and fillers. The coating may be applied by such methods as spraying, dip coating, curtain coating or flow coating. The coating is then baked, e.g. at 150‹-275‹F.</p> |
