GB384668A - A process for the manufacture of a foam-like mass - Google Patents

Abstract

Moulded porous masses of low specific gravity suitable as heat-insulating packing for rooms, containers, tubes, &c. are made by converting viscose into a foam, and then causing spontaneous hardening of the latter with regeneration of cellulose. The hardening or coagulation process may be assisted by heating, for example, to 90-100 DEG C., or by the addition to the foam of salts, glycerol, &c. The viscose used is preferably of high viscosity and of low alkali content; and its conversion to a foam is effected by beating or forcing in air, or by mixing with air or spraying through a spraying gun, or by mixing with substances which give off gases, the process of foam formation being assisted by the addition of proteins, soap, oleic acid, saponin, dextrin, rubber materials, &c. To the foam there may be added colouring matters, fillers or binders such as fibres, cork, sawdust, gypsum, cement, &c., and also plasticizers such as glycerol, glycol, and other hygroscopic substances which may render the material permanently flexible; and in the foam and the coagulated material there may be incorporated substances such as ammonium salts or borax that reduce its inflammability, and water-repelling substances such as aluminium soaps, latex, phenolic condensation products, paraffin emulsions, tar products, &c. Coagulation may be carried out in open dishes, tubes, etc.; and the moulds may be of pasteboard or paper, the latter strengthening the surface layers of the moulded mass. By a preliminary drying before washing, the surface layers of the coagulated masses may be strengthened; and the pores of the material may be opened or burst as by the passage of needles or the application of sudden pressure. The material can be softened by moistening or by treatment with steam, and the softened material can be worked into new forms by bending, pressing, &c.ALSO:Porous masses of low specific gravity suitable as heat-insulating packing for rooms, containers, tubes, &c. are made by converting viscose into a foam and then causing spontaneous hardening of the latter with regeneration of cellulose. The hardening or coagulation process may be assisted by heating, for example to 90-100 DEG C., or by the addition to the foam of salts, glycerol, &c. The viscose used is preferably of high viscosity and of low alkali content; and its conversion to a foam is effected by beating or forcing in air, or by mixing with air or spraying through a spraying gun, or by mixing with substances which give off gases, the process of foam formation being assisted by the addition of proteins, soap, oleic acid, saponin, dextrin, rubber materials, &c. To the foam there may be added colouring matters, fillers or binders such as fibres, cork, sawdust, gypsum, cement, &c., and also plasticizers such as glycerol, glycol, and other hydroscopic substances which may render the material permanently flexible; and in the foam and the coagulated material there may be incorporated substances such as ammonium salts or borax that reduce its inflammability, and water-repelling substances such as aluminium soaps, latex, phenolic condensation products, paraffin emulsions, tar products, &c. Coagulation may be carried out in open dishes, tubes, &c., and the moulds may be of pasteboard or paper, the latter strengthening the surface layers of the moulded mass. By a preliminary drying before washing, the surface layers of the coagulated masses may be strengthened; and the pores of the material may be opened or burst as by the passage of needles or the application of sudden pressure. The material can be softened by moistening or by treatment with steam, and the softened material can be worked into new forms by bending, pressing, &c.