GB833649A - Improved epoxide resin compositions - Google Patents

Abstract

Epoxide resin compositions capable of thermosetting in admixture with a hardener for epoxide resins and suitable as adhesive for glass-to-glass and metal-to-metal surfaces, e.g. as structural adhesives in the aeroplane industry, consist of 100 parts by weight of low molecular weight epoxide resin and 3-60 parts of a liquid copolymer of 55-74 parts butadiene with 45-26 parts acrylonitrile. The compositions are used particularly to impregnate fibrous glass. Silica, alumina, and powdered aluminium may be used as fillers. The epoxide resins are preferably prepared from bis-phenol and epichlorhydrin in presence of alkali or from glycerol and epichlorhydrin in presence of boron trifluoride catalyst. Suitable resin may also be prepared by epoxidizing unsaturated hydrocarbon oils, e.g. soybean oil or unsaturated copolymers of butadiene with hydrogen peroxide. Curing may be effected in presence of the usual organic acid anhydrides, amines, amides, diisocyanates, ureaformaldehyde resins, glyoxal and aromatic polysulphonic acids. A liquid butadiene-acrylonitrile polymer is obtained by reacting butadiene and acrylonitrile in water with Na lauryl sulphate as emulsifier and potassium persulphate and tertiary dodecyl mercaptan as catalyst. Examples of compositions are: (1) epoxide resin 100 parts, chlorendic anhydride 195 parts, butadiene copolymer 17 parts, powdered silica 7 parts; (2) as in (1) with addition of dimethylbenzylamine; (3) as before with maleic anhydride or hexhydrophthalic anhydride in conjunction with the dimethylbenzylamine; (4) dicyandiamide used as curing agent; (5) metaphenylenediamine as curer; (6) dihydrazides as curers; (7) abrasive sheets are obtained by coating with abrasive a vulcanized sheet impregnated with the resinous composition. Glycerol type epoxide resin were also used; (8) a moulding composition comprises an epoxide resin, butadiene copolymer and phthalic anhydride; a table is given of the variation in curing times with various proportions of epoxide resin and copolymer; (11) the composition was used to impregnate layers of non-woven linearly aligned glass fibres which were made into pipes and tubes. Mercaptobenzothiazol, tetraethylthiuram disulphide and zinc oxide may be added as cure accelerators.