GB705517A - Improvements in or relating to synthetic resinous material reinforced with fibrous asbestos - Google Patents

Abstract

705,517. Resin-bonded fibrous sheet material; laminated material. NATIONAL RESEARCH DEVELOPMENT CORPORATION. April 16, 1952 [April 19, 1951], No. 9207/51. Class 140 Synthetic resinous material reinforced with substantially parallel asbestos fibres is produced by subjecting asbestos rock to pressure in one direction transversely of the general direction in which the fibres extend so as to maintain their natural parallelism, impregnating the resulting loosened mass of fibres with a softenable or removable binding material, pressing, and slicing to produce layers of which the fibres are substantially parallel to the surfaces. The layers may then be arranged in a stack with their fibres parallel and subjected to pressure applied perpendicular to the general planes of the layers after softening or removing the binding agent. The operations of slicing into layers, arranging the layers in a stack, in a different order, or with some layers reversed, if desired, and repressing, may be repeated once or oftener. Subsequently, the binding agent may be removed, and the layers impregnated with a curable synthetic resin and subjected to the curing treatment. A number of layers may be partly cured, superimposed to form a stack with the fibres in different layers parallel or at chosen angles, and the cure completed by hot-pressing. The softenable binding material may be a component or the whole of the resinous material of the finished product, or a removable binding agent such as paraffin wax, zinc nitrate, Rochelle salts, or ice may be used. Paraffin wax may be removed from a stack containing it by boiling it in carbon tetrachloride while enclosed in a copper gauze envelope. Specifications 636,237 and 662,331 are referred to.