Patent GB-566086-A (GB)
Title: Improvements in or relating to neoprene compositions
IPC: C08K3/30
Filed: 1943-03-22
Abstract: Synthetic caoutchouc is prepared by polymerizing chloroprene in the presence of sulphur in amount up to 2 per cent of the chloroprene, the polymerization being preferably carried out in an emulsion; emulsifying-agents, antioxidants, polymerization-controlling agents, &c. may be added.  According to examples: (a) sulphur dissolved in chlorinated naphthalene is added to the chloroprene containing wood rosin, the solution is emulsified with water containing ammonium persulphate, the sodium salts of dinaphthylmethane sulphonic acids and sodium hydroxide, this dispersion being maintained at 40 DEG  C. until the density reaches 1.05 and then treated with phenyl-b -naphthylamine dispersed in sodium abietate solution, neutralized with acetic acid, coagulated into a sheet in the manner described in Specification 504,466, washed, dried and milled with tetramethyl thiuram disulphide; (b) chloroprene is emulsified in a solution of the sodium salts of sulphated oleyl acetate, sodium thioglycollate, and sodium hydrosulphide in water to which hydrochloric acid is added, a dispersion of phenyl-b -naphthylamine and tetramethyl thiuram disulphide in water containing sulphated oleyl acetate sodium salts is added, and the dispersion is coagulated by agitation with hydrated aluminium sulphate.  The products can be cured by means of sulphur chloride.ALSO:A composition which can be cured relatively quickly at low temperatures comprises polymerized chloroprene and sulphur chloride.  The chloroprene is preferably polymerized in the presence of free sulphur up to 2 per cent by weight of the chloroprene.  The polymerization is preferably carried out in an emulsion.  Emulsifying-agents, antioxidants, polymerization-controlling agents, &c. may be added.  According to examples: (a) sulphur dissolved in chlorinated naphthalene is added to the chloroprene containing wood rosin, the solution is emulsified with water containing ammonium persulphate, the sodium salts of dinaphthylmethane sulphonic acids and sodium hydroxide, this dispersion being maintained at 40 DEG  C. until the density reaches 1.05 and then treated with phenyl-b -naphthylamine dispersed in sodium abietate solution, neutralized with acetic acid, coagulated into a sheet in the manner described in Specification 504,466, [Group IV], washed, dried and milled with tetramethyl thiuram disulphide; (b) chloroprene is emulsified in a solution of the sodium salts of sulphated oleyl acetate, sodium thioglycollate, and sodium hydrosulphide in water to which hydrochloric acid is added, a dispersion of phenyl-b -naphthylamine and tetramethyl thiuram disulphide in water containing sulphated oleyl acetate sodium salts is added, and the dispersion is coagulated by agitation with hydrated aluminium sulphate.  These substances are compounded with other ingredients, e.g. hexamethylene-ammonium-hexamethylene-dithiocarbamate, phenyl - b  - naphthylamine, zinc oxide, carbon black, xylene and a hydrogenated substitute of toluene, or diorthotolyl guanidine, magnesium oxide, zinc oxide, phenyl-b -naphthylamine, blanc fixe and chlorinated diphenyl, and when treated with sulphur chloride produce a brushable coating or putty-like substance which cures at room temperature.  If the material is to be stored, a small amount of an alcohol or ketone having not more than 5 carbon atoms and volatile at ordinary temperatures may be added.  An acid acceptor, e.g. zinc or magnesium oxide, may be added to prevent corrosion of a metal surface to which the composition is applied. Surface vulcanization only can be effected by brushing on the sulphur chloride.