GB519724A - Improvements in or relating to heat-insulating materials - Google Patents

Abstract

519,724. Porous fibrous compositions. TURNER & NEWALL, Ltd., and WILSON, G. Sept. 22, 1938, No. 27689. [Classes 70 and 87 (ii)] [Also in Group VIII] Heat insulation having a cellular structure is obtained by agitating in a hollander or the like a dilute liquid stock of vegetable fibres consisting predominantly of peat, concentrating the stock, chemically generating a gas in it without chemically affecting the fibres, and drying the stock in the desired shape while retaining the gas in it. The gas may be generated by the addition of an acidic substance such as aluminium sulphate and a carbonate or bicarbonate, e.g. sodium bicarbonate. A foamstabilizing agent such as saponin or liquorice may be. added to retain the gas in the stock. The fibres may be rendered water-repeHent by adding an emulsion of bitumen, wax, or oil, or a mixture of soap and aluminium sulphate. Vermin-proofing agents such as cresol and fire-resisting. agents such as sodium ammonium phosphate, ammonium phosphate, or asbestos, may also be added. The finished product may be coated with Portland, gypsum, or magnesium oxychloride cement. In an example, a mixture of peat 85 per cent., and wood pulp 15 per cent. is beaten with water in a paper beater at a concentration of 0.6-1 per cent., and asbestos with soluble soap and aluminium sulphate added. The mixture is concentrated to 10-14 per cent., and for each 100 parts of the original dry stock there are added aluminium sulphate 11 parts, saponin 0.4 parts and sodium bicarbonate 8.5 parts, and the mixture agitated. Vermin-proofing and. fire-proofing agents may be added at this stage. The mixture is poured into a mould with a filter .bottom and then dried in a humid atmosphere, the humidity being gradually reduced, first at. 250‹F. and finally up to 300‹F. ,