Patent GB-717895-A (GB)
Title: Improvements in or relating to quaternary ammonium salts as processing aids in foam rubber
IPC: C08J9/30
Filed: 1952-11-19
Abstract: Foam rubber having a fine continuous structure is produced by incorporating vulcanizing ingredients, a gelling agent, and a relatively small amount of a quaternary ammonium salt having the formula <FORM:0717895/IV (a)/1> wherein at least one of R1, R2, R3, R4 is an aliphatic hydrocarbon radical or a substituted aliphatic hydrocarbon radical having a carbon chain containing 4 or more carbon atoms and the remainder of said R1, R2, R3, R4 are monovalent organic radicals or two together are a divalent organic radical, or the nitrogen forms part of a heterocyclic ring, and Anis a salt forming anion, into a synthetic rubber latex, frothing, allowing to set to an irreversible gel and then vulcanizing the gelled froth.  The salt-forming anion may be a phosphate, sulphate, carbonate, formate, acetate, or oxalate.  Many such salts are specified, typical of which are N-cetyl pyridinium chloride, cetyl dimethyl ethyl ammonium bromide, lauroyl imidazoline carbonate, dodecyl tri-(2-hydroxyethyl) ammonium chloride, N-octadecyl dimethyl ethyl bromide, and amyl trimethyl ammonium acetate.  The synthetic rubber may be a polymer of 1, 3-butadiene, piperylene, dimethyl butadiene, isoprene, or 2-chloro 1, 3-butadiene or copolymers of these monomers with each other or with acrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile, styrene, vinyl toluene, vinyl naphthalene, methyl acrylate, methyl methacrylate and acrylamide.  Coagulation of the latex is prevented by adding an anionic emulsifier such as a soap and non-ionic emulsifier or an alkali metal hydroxide.  In examples, to a latex containing natural rubber, GR-S, or polybutadiene, and soap, sulphur and an accelerator, is added various quaternary ammonium salts according to the invention and the latex, after frothing, is gelled with an alkali metal silicofluoride ammonium nitrate or ammonium sulphite. Zinc oxide, zinc salts of mercaptobenzthiazole, benzothiazole disulphide, zinc diethyldithiocarbamate, piperidinium pentamethylene dithiocarbamate and tetramethyl thiuram disulphide may also be added.ALSO:Foam rubber having a fine continuous structure is produced by incorporating vulcanizing ingredients, a gelling agent, and a relatively small amount of a quaternary ammonium salt having the formula <FORM:0717895/V/1> wherein at least one of R1 R2 R3 R4 is an aliphatic hydrocarbon radical or a substituted aliphatic hydrogen radical having a carbon chain containing 4 or more carbon atoms and the remainder of said R1 R2 R3 and R4 are monovalent organic radicals or two together are a divalent organic radical, or the nitrogen forms a part of a heterocylic ring and An is a salt forming anion, into a natural synthetic rubber latex, frothing the latex, allowing the latex to set to an irreversible gel and then vulcanizing the gelled froth. The salt forming anion may be a phosphate, sulphate, carbonate, formate, acetate or oxalate.  Many such salts are specified, typical of which are N-cetyl pyridinium chloride, cetyl dimethyl ethyl ammonium bromide, lauroyl imidazoline carbonate, dodecyl tri (2-hydroxyethyl) ammonium chloride, N-octadecyl dimethyl ethyl bromide, and amyl trimethyl ammonium acetate, Coagulation of the latex is prevented by adding an anionic emulsifier such as a soap and non ionic emulsifier or an alkali metal hydroxide.  In examples, to a latex containing natural rubber.  GR-S, or polybutadiene and soap, sulphur, and an accelerator, is added various quaternary ammonium salts according to the invention and the latex after frothing, is gelled with an alkali metal silico fluoride, ammonium nitrate or ammonium sulphite.  Zinc oxide, zinc salts of mercaptobenzthiazole, benzothiazole disulphide, zinc diethyldithiocarbamate, piperidinium pentamethylene dithiocarbamate and tetramethyl thiuram disulphide may also be added.