GB939437A - Novel resin compositions and process for curing the same - Google Patents

Abstract

A gel, curable by heat at above 60 DEG C. is made by mixing together an olefinically unsaturated polyester resin, a mono-olefinically unsaturated monomer copolymerizable therewith, an inhibitor, a free-radical polymerization catalyst which is an organic peroxide, percarboxylic acid or ester, or an azo-compound and which does not liberate sufficient free radicals at temperatures below 60 DEG C. to overcome the inhibitor and initiate cross-linking copolymerization, and a "gelator" which is a mixture of (a) an organic quaternary ammonium compound of the formula R1R2R3R4N+X-wherein R1-4 are: (i) C1-18 saturated or unsaturated hydrocarbon groups; (ii) C1-18 acyl groups; (iii) halogen or hydroxy substitution derivatives of (i) or (ii); (iv) combined in one or two pairs to form cyclic groups, e.g. pyridinium; or (v) organic quaternary ammonium salt groups bonded by divalent hydrocarbon groups to the N shown in the formula while X is: (i) an anion of an inorganic acid, e.g. hydrogen chloride bromide or iodide, or sulphuric or phosphoric acid, or of an organic acid, e.g. oxalic, acetic, citric, malonic, chloroacetic or lactic acid; or (ii) an hydroxyl group with (b) a mercaptan which is either a monomercaptan with the organic group selected from: (i) C1-20 alkyl and amino, nitro, and halogen substitution derivative thereof; (ii) aryl groups; and (iii) alkenyl groups, or a dimercaptan. The quaternary ammonium compound may first be mixed with the polyester resin and also function as the inhibitor. The mix may also include a metal organic salt soluble in the polyester resin, e.g. Cu, Co, Mn, Ca or Pb Naphthenate as accelerator for the final cure. The unsaturated polyester may be derived from maleic, fumaric, citraconic, chloromaleic, phthalic, terephthalic, adipic and sebacic acids and mono- or poly-ethylene and/or propylene glycols, 1,3-butylene glycol, 1,6-hexanediol and 2,2-dimethylpropane-1,3-diol. Mono-olefinic comonomers specified are styrene, ethylvinyl benzene, isopropenyl toluene, dimethylstyrene, vinyl benzoate, methyl acrylate and methacrylate, acrylonitrile and acrolein. Inhibitors specified are phenols, e.g. hydroquinone, p-t-butylcatechol, pyrogallol, trinitrophenol, 4-ethylcatechol, 3-phenylcatechol and 3-isobutyl catechol; quinones, e.g. quinone, tetrachloro-p-quinone, toluquinone and quinhydrone; aromatic amines, e.g. N,N1-di-beta-naphthyl-p-phenylenediamine, N,N1-diphenyl-p-phenylenediamine, p-hydroxy-diphenylamine and p-methyl-p1-sulphonamido diphenylamine; amine salts, e.g. tributylamine hydrochloride; ascorbic acid; trinitrobenzene and sulphur compounds. Free-radical catalysts specified are benzoyl, lauroyl, and MEK peroxides, t-butyl perbenzoate and azobisisobutyronitrile. The mixture may also contain pulverized fillers, e.g. calcium carbonate, barium sulphate, clay, and metal or glass powder and fibrous fillers, e.g. glass, cotton, jute asbestos and synthetic fibres. Several methods of processing the gels are specified including the formation of fibres which may be used for coating by attachment under pressure and heat-curing in situ; the lamination of unfilled sheets in a metallic mould; the lamination of contoured sheets reinforced with glass fibre, paper, cotton cloth, or knitted bamboo or wood plaits; spraying the liquid mixture and fibrous reinforcement simultaneously into a large-size mould to obtain the gel in the shape of the mould prior to heat-curing; and the formation of various-shaped moulding materials. Specified applications include the formation of tubes, buttons, boat hulls and car bodies.