Patent GB-726713-A (GB)
Title: Composition containing a glycidyl polyether and a polyvinyl acetal resin
IPC: C08L63/02
Filed: 1953-04-13
Abstract: A synthetic resin composition useful as a surface coating material or as an adhesive comprises (1) a glycidyl polyether of a polyhydric phenol having an average number of epoxy groups per molecule of greater than 1, and (2) a polyvinyl acetal resin. Normally the polyvinyl acetal resin is present in a minor proportion, e.g. 1-10 per cent by weight of the glycidyl polyether.  The composition may be cured by an amine or acidic curing catalyst.  The Specification lists suitable polyhydric phenols and curing catalysts.  The polyvinyl acetal resin preferably has a molecular weight of 20,000-100,000, and is preferably derived from polyvinyl acetate with from 50-100 per cent of the acetyl groups replaced with aldehyde groups from a saturated aldehyde having 1-4 carbon atoms.  The composition may be prepared by melting the components together or by combining them in a solvent, e.g. acetone, methyl ethyl ketone, diacetone alcohol, methyl isobutyl ketone or isophorone; ethyl acetate, butyl acetate or the acetate of monoethyl ether of ethylene glycol; the methyl, ethyl or butyl ether of ethylene or diethylene glycol; ethylene dichloride, trichloropropane or chloroform; or a mixture of toluene or xylene with a ketone, isopropanol, n-butanol, or an ester of a lower alcohol.  the compositions may also contain dyes, pigments, other resins, plasticizers or fillers.  The glycidyl polyethers used in the examples are prepared as follows: (a) bis-phenol (225 mols.) is heated with epichlorhydrin (22.5 mols.) while adding sodium hydroxide solution in instalments and distilling off epichlorhydrin and water. When the reaction is completed, excess epichlorhydrin is distilled off, the product dissolved in benzene and freed from precipitated salt and the solution distilled to yield a resin of M.W.370 and epoxy equivalency 1.85; (b) bis-phenol (0.056 mols.) is condensed with epichlorhydrin (0.15 mols.) to yield a resin of M.W. 460 and epoxy equivalency 1.88; (c) bis-phenol (1 mol.), epichlorhydrin (2.04 mols.) and aqueous sodium hydroxide solution are heated to 95 DEG  C. and the resinous layer washed and dried at 130 DEG  C. to yield a resin of M.W. 520 and epoxy equivalency 1.8; (d) a resin of M.W. 900 and epoxy equivalency 0.20 was prepared as in (c) from bis-phenol (1 mol.) and epichlorhydrin (1.57 mols.); (e) a resin of M.W. 1,400 and epoxy equivalency 1.54 was prepared as in (c) from bis-phenol (1 mol.) and epichlorhydrin (1.22 mols.); (f) 100 parts of polyether D are heated to 200 DEG  C. with 5 parts of bis-phenol to yield a resin of M.W. 2,900 and epoxy equivalency of 1.45.  In examples (1) and (2) coating compositions are made by adding ethylene diamine to a mixture of polyether C or D and polyvinyl acetal dissolved in a mixture of xylene and butanol; (3) coating compositions comprises a mixture of polyether A, E or F and polyvinyl formal or polyvinyl butyral dissolved in a mixture of ethylene dichloride, diacetone alcohol, xylene and the acetate of monoethyl ether of ethylene glycol; (4) an adhesive for bonding metals comprises a mixture of polyether B, polyvinyl acetal, allyl glycidyl ether and N,N-diethyl-1,3-propane-diamine.