Patent GB-826161-A (GB)
Title: A process for the production of cellular bodies
IPC: C08J9/04
Filed: 1956-09-19
Abstract: Expanded cellular bodies are produced from natural rubber, synthetic rubber, polyisoolefines and other elastomers in a process comprising mixing the elastomer with a lignin product, i.e. the product of chemical digestion of a lignin-containing raw material, and a solvent for the elastomer having a boiling point higher than the vulcanization temperature of the elastomer, and/or a plasticizer, without including in the mixture any inorganic filler, e.g. carbon black or aluminium silicate, in excess of 20% by weight of elastomer, and then expanding the mixture.  A specified lignin product containing ligninsulphonic acid or its compounds is sulphite cellulose waste liquor.  This liquor may be used as such (after evaporation and preferably drying) or after conversion to other forms, e.g. by precipitation with lime or by fermentation.  The elastomer can be mixed with 50 to 150% of its weight of lignin product, with or without filler, and 5 to 20% by weight, relative to lignin product, of solvent, preferably a lower polyhydroxy alcohol such as glycol or glycerine, and/or plasticizer, e.g. mineral oil product preferably containing a preponderance of unsaturated hydrocarbons such as Naftolen. Porosity is obtained by incorporating a blowing agent in the mixture in an amount of 3 to 10% of elastomer, or by using an inert gas before, during, or after vulcanization. Sulphur can be employed to harden the product.  In three examples the products obtained from fermented and unfermented sulphite liquors after evaporation and drying are incorporated in compositions containing natural and synthetic rubbers.  Other compounds used in the examples, other than the plasticizers and solvents specified above, are acetic and stearic acids, paraformaldehyde, aniline, benzenesulphonic acid hydrazide, antimony pentasulphide, magnesium carbonate, zinc oxide, mercaptobenzthiazole, diphenyl guanidine, tetramethylthiuram disulphide, and phenyl b -naphthylamine.ALSO:Expanded cellular bodies are produced from natural rubber, synthetic rubber, polyisoolefines and other elastomers in a process comprising mixing the elastomer with a lignin product, e.g. the product of chemical digestion of a lignin-containing raw material, and a solvent for the elastomer having a boiling point higher than the vulcanization temperature of the elastomer, and/or a plasticizer, without including in the mixture any inorganic filler, e.g. carbon black or aluminium silicate, in excess of 20% by weight of elastomer, and then expanding the mixture. A specified lignin product containing ligninsulphonic acid or its compounds is sulphite celluslose waste liquor.  This liquor may be used as such (after evaporation and preferably drying) or after conversion to other forms, e.g. by precipitation with lime or by fermentation.  The elastomer can be mixed with 50 to 150% of its weight of lignin product, with or without filler, and 5 to 20% by weight, relative to lignin product, of solvent, preferably a lower polyhydroxy alcohol such as glycol or glycerine, and/or plasticizer, e.g. mineral oil product preferably containing a preponderance of unsaturated hydrocarbons such as Naftolen. Porosity is obtained by incorporating a blowing agent in the mixture in an amount of 3 to 10% of elastomer, or by using an inert gas before, during, or after vulcanisation.  Sulphur can be employed to harden the product.  In three examples the products obtained from fermented and unfermented sulphite liquors after evaporation and drying are incorporated in compositions containing natural and synthetic rubbers.  Other compounds used in the examples, other than the plasticizers and solvents specified above, are acetic and stearic acids, paraformaldehyde, aniline, benzenesulphonic acid hydrazide, antimony pentasulphide, magnesium carbonate, zinc oxide, mercaptobenzthiazole, diphenyl guanidine, tetramethylthiuram disulphide and phenyl b napthhylamine.