Patent GB-735531-A (GB)
Title: Improvements in and relating to unsaturated acidic polyester ethoxyline resinous compositions
IPC: C08F2/00
Filed: 1952-10-09
Abstract: A resinous composition consists of an acidic polymerizable ester containing a free carboxyl group and formed by reacting a dihydric alcohol and an a ,b -unsaturated dicarboxylic acid together with a polyether derivative of a polyhydric organic compound containing epoxy groups.  Suitable reactants for preparing the polymerizable ester are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, or 1,4-butanediol, and maleic, fumaric or itaconic acid or anhydride.  Up to 90 mol. per cent of the unsaturated acid may be replaced by succinic, adipic, glutaric, azelaic, sebacic, phthalic, isophthalic or terephthalic acid or anhydride.  Preferably a molar excess of acid is employed, and the acid number of the polyester is above 50. The reaction mixture may include a polymerization inhibitor, e.g. p-tert. butyl catechol. Suitable epoxy bodies are as described in Specifications 518,057 and 579,698.  In general they are produced by reacting an epihalohydrin with a polyhydric phenol, e.g. bis-(4-hydroxyphenyl) dimethylmethane, hydroquinone or resorcinol, or a polyhydric alcohol, e.g. glycerine. The preferred proportion of the polyester in the composition is 5-75 per cent by weight.  The components are preferably blended at elevated temperature, e.g. while fluid.  They combine chemically. Reaction is stopped by cooling to yield a fusible, soluble resin useful for coating, moulding, laminating or adhesive composition. The products are heat-curable.  Suitable curing catalysts are peroxides, e.g. acetyl, lauroyl, stearoyl, benzoyl, or acetylbenzoyl peroxide; tert. butyl perbenzoate, tert. butyl hydroperoxide, cyclohexyl hydroperoxide-1, azo compounds, e.g. a ,a 1-azo-bis isobutyronitrile. Preferred catalyst concentration is 0.1-2 per cent by weight of the polyester.  The compositions may be copolymerized with for example styrene, methyl methacrylate, ethyl acrylate, vinyl acetate or diallyl phthalate.  Suitable solvents for the compositions are acetone, methyl ethyl ketone, ethyl Cellosolve (Registered Trade Mark), cyclohexanone, cresylic acid, diacetone alcohol or isophorone. Suitable diluents are benzene, toluene or solvent naphtha.  The compositions may includes fillers, e.g. glass fibres, mica, clay, TiO2, iron oxide, carbon, graphite, asbestos or glass fibres.  In the examples (1) a polyester from ethylene glycol and maleic acid was blended for 1 1/2 hours at 150-160 DEG  C. with a resin known as Epon.  Quinone was present.  The product cured by heating in air or with addition of benzoyl- or butyl hydro-peroxide.  Dissolved in acetone and benzene it gave a film-forming composition with good adhesion to copper.  (2) The composition of example (1) was mixed with a polyvinyl formal in ethylene dichloride.  The solution yielded flexible adherent, films on copper strips.  Mixed with acetone, clay, asbestos and benzoyl peroxide the composition of example (1) was suitable for moulding.  Other similar examples include inter alia the use of ethylene glycol fumarate as the polyester, the use of copolymerisates of the compositions of the invention and allyl phthalate for laminating glass cloth, the use of compositions according to the invention for coating and impregnating asbestos tape as in Specification 735,532, [Group XXXVI], the use of a polyester from ethylene glycol, maleic anhydride and adipic acid and copolymerization of the compositions of the invention with styrene.