Patent GB-756645-A (GB)
Title: Manufacture of foamed latex sponge
IPC: C08J9/00
Filed: 1954-09-07
Abstract: In manufacturing foamed latex sponge compounded with glass fibres are incorporated in natural and/or synthetic rubber latex in the form of an aerated slurry, containing at least one non-anionic surface-active agent.  The latter may be cationic, e.g. a quaternary ammonium salt in which at least one of the radicals attached to the nitrogen atom has 8 to 24 carbon atoms, or may be non-ionic, e.g. a polyethylene-glycol alkyl-phenyl ether.  Surface-active agents specified are those specified in the parent Specification.  Synthetic rubbers specified are polymers of butadiene-1,3, or a mixture of butadienes-1,3, or copolymers of butadiene-1,3 with styrene, vinyl naphthalene, acrylic acid, methyl arylate, acrylonitrile, methacrylamide, a methyl vinyl ether, or ketone, or vinylidene chloride.  Preferably the weight of non-anionic surface-active agents in the slurry is 0.2 to 8 grams per c.c.  The slurry is prepared by mixing the fibres in water containing the surface-active agent, or by mixing the fibres having the surface-active agent on their surface in water, in a mixing device which forms a vortex which draws air into the liquid.  Air may also be blown into the mixture in the device. The latex is prepared for foaming by adding thereto an anionic surface-active agent.ALSO:In a method of manufacturing foamed latex sponge in which glass fibres are compounded with natural and/or synthetic rubber, the glass fibres are incorporated in the latex in the form of an aerated slurry containing at least one non-anionic surface-active agent.  The latter may be cationic, e.g. a quaternary ammonium salt in which at least one of the radicals attached to the nitrogen atom has 8 to 24 carbon atoms, or may be non-ionic, e.g. a polyethylene-glycol alkyl-phenyl ether.  The surface-active agents specified are those specified in the parent Specification. Preferably the weight of non-anionic surface active agent in the slurry is 0.2 to 10 per cent of the weight of the glass fibres, and the density of the aerated slurry is 0.2 to 8 grams per cc. The slurry is prepared by mixing the fibres in water containing the surface-active agent, or by mixing the fibres having the surface agent on their surface in water, in a mixing device which forms a vortex which draws air into the liquid.  Air may also be blown into the mixture in the device. The latex is prepared for foaming by the addition thereto of an anionic surface-active agent.  In an example a blend of 120 parts natural rubber latex and 33.3 parts GRS synthetic rubber latex is mixed with potassium oleate and potassium ricinoleate soaps, and vulcanizing and other ingredients, and the mixture is whipped into a foam.  An aqueous slurry of glass fibres is prepared by stirring the fibres into water containing the acetate salt of a mixture of long-chain aliphatic amines (a cationic surface-active agent), and poly-ethylene-glycol-monoiso-octyl phenyl ether (a non-ionic surface-active agent), the stirring being continued with drawing of air into the slurry until the density thereof is 0.4 gms./cc. The aerated slurry is mixed with the foamed latex, sodium silicofluoride gelling agent added, and the foam permitted to gel at room temperature and then vulcanized at 212 DEG F.  Alternatively the slurry is added to the latex before foaming.