GB642350A - Improvements in or relating to resinous compositions - Google Patents

Abstract

A composition capable of being completely polymerized to a thermoset copolymer against copper with little or no discolouration consists of a solvent composed of 100 parts by weight of a polymerizable liquid monomer having a CH2=C< group and a solute comprising from 5 to 300 parts of the complex ester reaction product of an acidic castor oil-a ,b unsaturated dicarboxylic acid half ester having an average of at least two free carboxyl groups per molecule with from 1/2 to 1 1/2 molar equivalents based on the half ester of at least one compound of the group consisting of alkylene oxides and dihydric alcohols. Suitable dicarboxylic acids and anhydrides are maleic acid and anhydride, fumaric acid, citraconic anhydride and monochlormaleic anhydride. The full acid half ester of castor oil is preferred and in the case of maleic anhydride may be prepared by heating 100 parts of castor oil with 30 parts of anhydride at a temperature of 120 DEG C. for 4 hours. Suitable dihydric alcohols and alkylene oxides are ethylene, propylene and trimethylene glycols, 2-ethylhexanediol-1,3, diethylene glycol, 1,3-butanediol, 1,4-dihydroxy butene-2, bis-hydroxypropyl maleate, propylene oxide and butadiene monoxide. The complex esters are formed by heating the castor oil half ester and the alcohol and/or oxide up to 190-200 DEG C. for several hours in the presence of quinhydrone while stirring and sraying with carbon dioxide. Gellation is avoided by rapid cooling resulting in viscous oils. The tendency to gel may be reduced by first reacting the castor oil half ester with a monohydric saturated alcohol, e.g. n-butanol, to terminate about one carboxyl group per molecule and then reacting with the dihydric alcohol or alkylene oxide. The monomer solvent, e.g. styrene, distyrene, p-methyl styrene, vinyl acetate, methyl vinyl ketone, acrylonitrile, methyl methacrylate, ethyl acrylate, and allyl esters such as diallyl phthalate, may be copolymerized with the complex ester in the presence of a catalyst such as tert.-butyl perbenzoate, ascaridole and lauroyl and benzoyl peroxides. The solution may be heated to 50-250 DEG C. In some cases, ultra-violet light may be used in combination with a catalyst with or without heating. The compositions are useful for electrical insulation and may be cast and used for impregnating cloth. They may be combined with asbestos fibres, glass fibres, mica powder, silica, wood flour, cotton cloth, asbestos paper and pigments and dyes. The products may be machined, sawn, drilled and sanded.ALSO:200 Parts of propylene oxide are added over a period of 3 hours to 150 parts of maleic acid in a vessel maintained at 95-105 DEG C. After further refluxing for 2 hours, 50 more parts of propylene oxide are added while the temperature is raised to 105 DEG C. over a two-hour period. The product is refluxed for 4 hours, yielding bis-hydroxypropyl maleate, a light yellow oil.