GB532532A - Improvements in or relating to heat convertible synthetic resin compositions - Google Patents

Abstract

532,532. Synthetic resin compositions. INTERCHEMICAL CORPORATION. July 24, 1939, Nos. 21466 and 21467. Convention dates, April 12 and July 11. [Class 2 (iii)] A heat-convertible synthetic resin composition which does not discolour at high temperatures comprises a urea-formaldehyde resin soluble in organic solvents and a heat-convertible alkyd resin consisting of the reaction product of a polyhydric alcohol, phthalic acid and one or more of lauric, myristic and palmitic acids, which acids are substantially free from unsaturated fatty compounds and containing less than 10 per cent. of other saturated acid. The fatty acid constitutes 20-60 per cent. of the alkyd resin and the ratio of alkyd to urea resin is between 1:5 and 5:1. Phthalic acid may be replaced by other dibasic acids up to a few per cent. To avoid discoloration, the urea resin should be prepared from formaldehyde and urea or urea derivatives other than thiourea and other discolouring derivatives, and the finished composition should be substantially free from non-volatile fatty acid compounds. Examples are given of the preparation of (1) a urea resin by heating together formaldehyde and phosphoric acid, adding urea in stages at 60-65‹C., then raising the temperature to 85-90‹C. and, after a time adding n-butanol and mildly refluxing at 90-95‹C. and finally distilling off water and butanol and adjusting the solution to a 50 per cent. non-volatile content; (2)-(6) alkyd resins from phthalic anhydride, glycerine and lauric (2 and 3), myristic (4 and 5) and palmitic (6) acids by heating to 450‹F. in an aluminium kettle in an atmosphere of carbon dioxide ; (7) a coating composition by mixing the urea resin solution of (1) with a xylol solution of (2) and titanium oxide, which composition may be sprayed on metal and baked for 30 minutes at 250 F. or 10 minutes at 350 F., and (8) and (9) moulding compositions by blending the urea resin, preferably with some of the solvent removed, with the solid alkyd resin on a two-roller mill to produce a powder which can be moulded at 350‹F. under a pressure of 2,000 lb. per sq. inch for 10 minutes.