Abstract: An unsaturated polyester resin composition for ambient temperature open lay-up moulding contains styrene as an agent for cross-linking during curing, a wax for preventing air inhibition and a compound for allowing reduction of styrene evaporation. The compound is of the formulaR.sub.1 --X--CH.dbd.CHCOOHwhere R.sub.1 is a straight- or branched-chain substituted or unsubstituted aliphatic C.sub.6 --C.sub.24 hydrocarbon, and ##STR1## Such resin compositions are particularly suitable for producing laminates and the abovementioned compounds serve as adhesion-promoting agents. Incorporation of such compounds into the compositions enables larger amounts of the waxy substances to be included by compensating for the loss of adhesion which would otherwise have arisen from the presence of larger quantities of waxy substance.

Abstract: A polyester resin composition comprising a thixotropic solution of an unsaturated polyester resin in a volatile monomer containing also a polymer which is partially incompatible with the polyester resin solution i.e. forms a hazy solution in it. The partially incompatible polymer can be a polymer of an ester of an unsaturated carboxylic acid.

Abstract: An intumescent composition comprising a polymeric binder, a mineral acid catalyst, a source of carbon, and a blowing agent in which the polymeric binder is a solution of a plasticized unsaturated polyester in an unsaturated monomer.

Abstract: An intumescent composition comprising a resinous binder, an inorganic acid source, a carbon source and a blowing agent, the blowing agent comprises(a) a 2-amino s-triazine of general formula ##STR1## in which R.sup.1 and R.sup.2 are the same of different and are each selected from hydrogen, halogen, hydroxyl and amino groups and alkyl, substituted alkyl, alkenyl and substituted alkenyl groups containing up to 6 carbon atoms and(b) a saturated or unsaturated polybasic carboxylic acid containing no more than 2 non-carboxyl carbon atoms per carboxyl group.