Modified alkyd resins - by reaction with styrene or acrylates in selected amts for paints and lacquers

摘要

Alkyd resins are pref. by reaction of (A) 44-50 wt.% dehydrated castor oil (as triglyceride) or the equiv. amt. of castor oil fatty acid and glycerine, (B) 11-14 wt. % glycerine, (C) 4-12 wt.% 2-6C aliphatic diols and (D) 34-36 wt.% phthalic anhydride. After removal of reaction water, the resin is copolymerised with (E) 22-26 wt.% styrene and (F) 8-12 wt.% methyl methacrylate, based on wt. of end product. The intermediate alkyd resin has a ratio of OH to COOH gps. of 1:1.24-1.20 acid value 20 and viscosity G-O (Gardner -Holt) in 60% xylene soln. at 20 degrees C. They are suitable as binders for air-drying coatings e.g. repair lacquers, and mixed with melamine-formaldehyde resins, as binders for stoving lacquers. The compsns. show improved whiteness gloss, pigment acceptability, resistance to storage etc. and good flow, deep-draw props. and resistance to stacking, sterilisation and to yellowing.