A process for the manufacture of insulating paper, paste-board, card-board and moulded articles formed from fibrous masses

摘要

262,828. Friedlõnder, H. Dec. 14, 1925, [Convention date]. Electric insulating paper; pulp, adding special substances to.-In the manufacture of water resisting, pliable insulating paper, millboard, moulded articles and the like, hard waxes, or mixtures of such waxes, or bye-products thereof are added to pulp in the beating engine or edge runner mill. The waxy admixtures to be added to the pulp are obtained by boiling the wax products or mixtures thereof in a watery soap solution or dilute alkali until they become stiff or emulsified and dilutable or miscible with water. Enough of this is added to the pulp to give 30-50 per cent of wax in the dry paper or the like obtained. The emulsion may contain the usual dyeing, filling or similar agents and is separated out in the paper by aluminium sulphate, alum, or the like, and the paper is made in the usual way with final hard calendering which may be by stone polishers. Resin sizes may be used with the waxes. In an example, 80 per cent montan wax, 12 per cent carnauba wax and 8 per cent coumaron resin are used together. Other materials mentioned are montan pitch, colophonin, and phenol artificial resin. The waxes used should preferably have been previously subjected to separate hardening, clarifying, and refining processes. Millboards, slabs, tubes, and the like, so produced may be subjected to impregnation with hard wax as described in Specification 236,224.