| 摘要 |
Coating compsn. contains (a) at least 50 wt.% of a film-forming binder consisting of (A) 50-95 wt.% of an acrylic polymer, with Mn by gel permeation chromatography of 500-10,000, from methyl methacrylate (I), a 2-12C alkyl (meth)acrylate and a 2-4C hydroxyalkyl (meth)acrylate, and up to 30 wt.% of styrene, and (B) 50-5% of a nitrogenous resin cross-linking agent; (b) up to 50 wt.% of a liq. carrier; and (c) 0.1-20 wt.%, w.r.t. the binder, of an ultraviolet light stabiliser. (a) Pref., the binder content is 60-85%. (A) The polymer pref. has Mn 500-4500 (1000-3500), 2-10 wt.% OH, glass transition temp., Tg, between -20 deg.C and 20 deg.C and 2-10% of a chain transfer agent, e.g. butyl mercaptan. The compsn. is esp. used as a clear top coat over a coloured coat, e.g. as a finish for automobiles and aircraft. It is partic. useful as a repair compsn. for powder coating finishes contg. flake pigments, e.g. Al flakes. The coating has a high solids content, and resists weathering. |
