GB777793A - Improvements in the production of linear unsaturated polyesters - Google Patents

Abstract

An unsaturated polyester is made by reacting (a) an unsaturated alpha, beta-dicarboxylic acid (e.g. maleic or fumaric) with (b) a diester of a polyhydric alcohol containing two carbocyclic rings and an endomethylene bridge and having the hydroxyl groups joined to nuclear carbon atoms with a monocarboxylic acid containing up to three carbon atoms. Specified diesters are those of formul <FORM:0777793/IV(a)/1> and <FORM:0777793/IV(a)/2> in which R is hydrogen, methyl or ethyl. Part of the unsaturated dicarboxylic may be replaced by a saturated dicarboxylic acid and part of the endocyclic diester may be replaced by a conventional diol (e.g. ethylene, diethylene, 1,3-butylene, 1.4-butylene, or 1,6-hexylene glycol). Monocarboxylic acids and monohydric alcohols may also be included in the reaction. The products may be copolymerized with styrene, alkyl styrenes, chlorstyrenes, vinyl naphthalene or vinyl acetate in presence of organic peroxides, redox systems (e.g. benzoyl peroxide + a tertiary amine) and, if desired, driers (e.g. cobalt naphthenate). In examples maleic anhydride, phthalic anhydride, and a diformate corresponding to one of the above formul were polycondensed in presence of butyl alcohol (which forms dibutyl formate with the acid split off from the diester), hydroquinone and trichloroethyl phosphorous acid ester. The resulting polyester was then dissolved in styrene and methyl ethyl ketone peroxide dissolved in dimethyl phthalate and cobalt naphthenate added to form a coating composition. If it is desired to apply the solution with a spray gun, there is added butanol, ethylene glycol acetate and additional styrene. Specification 766,666 is referred to.