SE332020B - - Google Patents

Abstract

1,153,452. Thermosetting resin impregnated laminates. PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd. 27 Sept., 1966 [28 Sept., 1965], No. 43114/66. Heading B5N. A method of manufacturing a cold-punchable laminated material comprises the steps of impregnating sheets of fibrous material with an aqueous emulsion or solution of a phenolaldehyde resin, drying the impregnated sheets and partially curing the resin in the dried impregnated sheets, then forming a stack of a plurality of such impregnated sheets in which the resin was partially cured, compressing and heating the stack so that a single laminated body is formed and the resin hardened, wherein the phenol-aldehyde resin is manufactured from phenolfurfural and formaldehyde, wherein the molar ratio of phenol to total aldehyde used to constitute the resin is from 1 :1À1 to 1 1À5 wherein the molar ratio of phenol to furfural is from 1 : 0À6 to 1 : 0À9 and wherein the phenol is first treated with furfural in the presence of a basic catalyst. The basic catalyst may be an alkali metal carbonate and/or an alkaline earth metal hydroxide, the fibrous material may be kraft paper, the drying and partial curing may be effected in an oven and the compression may be between plates. In one example phenol, furfural and calcium hydroxide are heated and stirred together in a reaction vessel and a two layer distillate of water, phenol and furfural is given off. The reaction mixture is then cooled and formaline, and the phenol and furfural from the distillate added to the reaction mixture which is then boiled, to produce the desired impregnating resin. A solvent, e.g. stearamide, may be added to the resin either before adding an acid, e.g. sulphamic or sulphonilic acid, to reduce the pH, or after adding ammonia.