Patent GB-847504-A (GB)
Title: Method for making cellular materials
IPC: C08J9/06
Filed: 1956-12-10
Abstract: In a method of making a cellular material from a plastisol composition containing a vinyl chloride polymer or copolymer and a liquid plasticizer therefor in which the plastisol composition is formed into a cellular structure and the resulting structure is heated to gel and fuse the plastisol composition, degeneration or breakdown of the cellular structure of the ungelled foamed plastisol is minimized by adding thereto an aliphatic acid having 12 to 24 carbon atoms and a reactant capable of reacting with the acid at a temperature below the gelling temperature to form a fatty acid soap. The reactant may consist of two or more materials which react together at a temperature below the gelling temperature to form a reaction product which itself reacts with the aliphatic acid to form a soap. Preferably the reactant is one which is either decomposed by heat or reacts with another material in the plastisol to form a gas which expands the plastisol. Suitable reactants are the hydroxides of sodium, potassium, ammonium, calcium or barium ; the carbonates or bicarbonates of sodium, potassium and ammonium ; and the borohydrides of sodium, potassium, caesium and rubidium (Specification 799,750). When using a reactant which is also a blowing agent, a dilute acetic acid solution may be added to the plastisol to increase the rate of decomposition of the blowing agent.  Instead of the above blowing agents there may be used p,p'oxybis-(benzenesulphonylhydrazide), diazoamino benzene, dinitroso pentamethylene tetramine, N,N1-dimethyl-N,N1-dinitroso terephthalamide or silicon oxyhydride and water.  Also, foaming may be effected by mechanically entraining air in the plastisol.  In Examples, cellular masses were made as follows: (1) separate plastisol compositions were made comprising polyvinyl chloride, butyl benzyl phthalate, dibutyl tin dilaurate and either (a) a dispersion of silicon oxyhydride and stearic acid in dioctyl phthalate or (b) an aqueous ammonia solution-the compositions were then mixed and heated ; (2) separate plastisol compositions were made comprising polyvinyl chloride, isooctyl isodecyl phthalate and either (a) a dispersion of sodium borohydride in dioctyl phthalate or (b) aqueous acetic acid and a dispersion of stearic acid in dioctyl phthalate-the dispersions were then mixed and heated ; (3) separate plastisol compositions were made comprising polyvinyl chloride, butyl benzyl phthalate, dipropylene glycol dibenzoate, dioctyl phthalate and either (a) a dispersion of ammonium bicarbonate in dioctyl phthalate or (b) oleic acid and acetic acid-the dispersions were then mixed and heated ; (4) separate plastisol compositions were made comprising a vinyl chloride-vinylidene chloride copolymer, dioctyl phthalate and either (a) a dispersion of potassium borohydride in dioctyl phthalate or (b) aqueous acetic acid and a dispersion of stearic acid in dioctyl phthalate-the dispersions were then mixed and heated ; (5) a plastisol was made comprising a vinyl chloride-vinyl acetate copolymer, didecyl phthalate, dibutyl tin dilaurate and a dispersion of N,N1-dimethyl-N,N1-dinitroso terephthalamide in dioctyl phthalate-ricinoleic acid and aqueous potassium hydroxide were then added and the mixture heated ; (6) separate plastisol compositions were made comprising a vinyl chlorideethyl maleate copolymer, a vinyl chloridevinylidene chloride copolymer, didecylphthalate and either (a) sodium borohydride and aqueous sodium hydroxide or (b) a dispersion of palmitic acid in dioctyl phthalate-the compositions were then mixed and heated. Plasticizers specified in addition to those exemplified are butyl decyl phthalate, dioctyl adipate, dioctyl sebacate, acetyl tributyl citrate, tricresyl phosphate and trioctyl phosphate.ALSO:In a method of making a cellular material from a plastisol composition containing a vinyl chloride polymer or copolymer and a liquid plasticizer therefor in which the plastisol composition is formed into a cellular structure and the resulting structure is heated to gel and fuse the plastisol composition, degeneration or breakdown of the cellular structure of the ungelled foamed plastisol is minimized by adding thereto an aliphatic acid having 12 to 24 carbon atoms and a reactant capable of reacting with the acid at a temperature below the gelling temperature to form a fatty acid soap.  The reactant may consist of two or more materials which react together at a temperature below the gelling temperature to form a reaction product which itself reacts with the aliphatic acid to form a soap.  Preferably the reactant is one which is either decomposed by heat or reacts with another material in the plastisol to form a gas which expands the plastisol. Suitable reactants are the hydroxides of sodium, potassium, ammonium, calcium or barium; the carbonates or bicarbonates of sodium, potassium and ammonium; and the borohydrides of sodium, potassium, caesium and rubidium (Specification 799,750).  When using a reactant which is also a blowing agent, a dilute acetic acid solution may be added to the plastisol to increase the rate of decomposition of the blowing agent. Instead of the above blowing agents there may be used p, p1-oxybis-(benzenesulphonylhydrazide), diazoamino benzene, dinitroso pentamethylene tetramine, N, N1-dimethyl-N.N1-dinitroso terephthalamide or silicon oxyhydride and water.  Also, foaming may be effected by mechanically entraining air in the plastisol.