Wässrige autooxydierbare Überzugszusammensetzung

摘要

A water-based autoxidisable coating composition, especially a gloss or partial gloss coating composition (eg paint, varnish, woodstain or timber preservative) suitable for application at ambient temperatures which comprises water, minimal organic cosolvent and a partially esterified carboxylic acid film-forming copolymer at least partially neutralised by monovalent cations wherein the copolymer contains added 3-allyloxy-2-hydroxypropyl groups or certain analogues derived from addition of allyl glycidyl ether or certain of its analogues to carboxylic acid groups, in a copolymeric backbone portion derivable from a prepolymer of weight average molecular weight less than 30 000. The partially esterified copolymer has an acid value of 25 to 60 and preferably a dynamic solution viscosity of 1 to 500 Pa.sec measured in 1-methoxy-2-hydroxy propane by oscillatory parallel plate rheometer. The coatings lap well, dry quickly and achieve acceptable water resistance. Also the optionally unneutralised copolymer and the coating composition when containing a minor amount of particulate copolymer which is found to improve gloss. Discolouration on ageing may be improved by neutralising with Group 1 metal cations.