PROCESS FOR PRODUCING CURED PLASTICS ARTICLES

1,217,949. Process for producing cured plastics articles. DOW CHEMICAL CO. 11 Oct., 1968 [30 Oct., 1967], No. 48361/68. Heading C3P. [Also in Division F2] A cured plastics article is produced in two separate stages: in the first stage a composition comprising a thermosetting resin and one or more volatile monomers capable of reacting chemically with the resin, initially at a temperature below the boiling point(s) of the monomer(s) and below the temperature at which a gel is formed, is subjected to a rapid increase in temperature so as to form a gel within 5 minutes from the commencement of the temperature increase; and in the second stage the temperature of the resulting gel is raised to the curing temperature thereof to form a cured plastics article. Preferred monomer(s)/resin compositions are an unsaturated polyester resin containing an ethylenically unsaturated monomer; a vinyl ester resin, polymerizable with the monomer(s) used, containing an ethylenically unsaturated monomer; or an epoxy resin containing a volatile monoepoxy diluent. The resin/monomer mixtures used in the examples were a vinyl ester resin prepared from maleic anhydride, #-hydroxyethyl acrylate and a polyepoxide resin prepared from bisphenol A and a hydrogenated bisphenol polyester, both dissolved in styrene. This is cured on a mandrel either alone to form a liner or with wound fibreglass reinforcement.