GB392483A - Manufacture of artificial sponges and other porous structures - Google Patents

Abstract

Spongy cellulose masses are obtained by incorporating soluble salts with viscose and treating with a regenerating liquid at raised temperature and pressure. Dyestuffs and fibrous materials such as staple fibre, flax, jute, ramie, or coco-fibre may be incorporated in the viscose and the fibres may be swelled with alkali prior to being mixed with the viscose. Disinfectants, perfumes, and other substances may be mixed with the regenerating liquid and thus intimately mixed with the spongy cellulose. Bleaching agents may be incorporated in the regenerating liquid if desired. In order to prevent premature removal of the pore-forming salts, the regenerating bath is saturated with a salt but the solution may be diluted during or immediately on completion of regeneration. It is preferred to make the bath slightly alkaline, and before treating with the liquid under pressure, to expose the viscose mass during the mixing or whilst in the mould to a vacuum treatment. The moulded viscose mass may be first solidified by heat treatment and then treated with the hot regenerating liquid under pressure. In an example, viscose solution is mixed with a large proportion of crystallized sodium sulphate in grains of various sizes and with artificial or natural fibres. The mass is placed in moulds and set by heating at reduced pressure. It is then treated with saturated sodium sulphate solution containing one per cent of free caustic soda at 150 DEG C. and under several atmospheres of pressure. This treatment results in the production of a porous material which may be used as a sponge substitute, packing material, sound absorber, heat insulator, or as a filtering material.ALSO:Spongy cellulose masses are obtained by incorporating soluble salts with viscose and treating with a regenerating liquid at raised temperature and pressure. Dyestuffs and fibrous materials such as staple fibre, flax, jute, ramie, or coco fibre may be incorporated in the viscose and the fibres may be swelled with alkali prior to being mixed with the viscose. Disinfectants, perfumes, and other substances may be mixed with the regenerating liquid and thus intimately mixed with the spongy cellulose. Bleaching agents may be incorporated in the regenerating liquid. In order to prevent premature removal of the pore-forming salts, the regenerating bath is saturated with a salt but the solution may be diluted during or immediately after regeneration. The bath is preferably made feebly alkaline, and before treating with the liquid under pressure, the viscose is exposed during the mixing or whilst in the mould to a vacuum treatment. In an example, viscose is mixed with a large proportion of crystallized sodium sulphate in grains of various sizes and with natural or artificial fibres. The mass is placed in moulds and set by heating at reduced pressure. It is then treated with saturated sodium sulphate solution containing one per cent of caustic soda at 150 DEG C. and under several atmospheres of pressure. This treatment results in the production of a porous material suitable as sponge substitute, or for packing, sound absorption, heat insulation, or filtering.ALSO:Porous cellulose masses of spongy nature, which may be used as filtering-material, are obtained by incorporating soluble salts with viscose and treating with a regenerating liquid at raised temperature and pressure. Dyestuffs and fibrous materials such as staple fibre, flax, jute, ramie, or coco-fibre, may be incorporated in the viscose. The fibres may be swelled with alkali prior to being mixed with the viscose. Disinfectants, or bleaching agents may be incorporated in the regenerating liquid. The regenerating liquid is preferably slightly alkaline and saturated with a salt, and the viscose is subjected to vacuum treatment, prior to the treatment with regenerating liquid. The moulded viscose mass may be first solidified by heat and then treated with regenerating liquid. In an example, viscose is mixed with a large proportion of crystallized sodium sulphate in grains of various sizes and with artificial or natural fibres. The mass is placed in moulds and set by heating at reduced pressure. It is then treated with saturated sodium sulphate solution containing one per cent of free caustic soda at 150 DEG C. and under several atmospheres of pressure.