Patent GB-566016-A (GB)
Title: Improvements in or relating to neoprene compositions
IPC: C08L11/00
Filed: 1943-03-22
Abstract: Synthetic caoutchouc is prepared by stirring with chloroprene containing a small amount of wood rosin, a hot solution of sulphur in chlorinated naphthalene, and emulsifying with water containing ammonium pensulphate, the sodium salts of dinaphthyl methane sulphonic acids, and sodium hydroxide, the emulsion being maintained at 40 DEG  C. until the density reaches 1.05.  A dispension of phenyl-b -naphthylamine in sodium abietate solution neutralized p with acetic acid is then added and the product is coagulated in the form of a continuous sheet by freezing on a cooled rotating drum, washed, dried and milled with tetramethyl thiuram disulphide.  The product can be cured rapidly at ordinary temperatures by treatment with a mixture of litharge and a butyraldehyde-amine.ALSO:A composition which can be cured rapidly at ordinary temperatures and which can be used as a coating, caulking, moulding or adhesive composition, or as a covering for floors, decks or the like, consists of chloroprene polymerized in the presence of elementary sulphur, litharge and a butyraldehyde-amine, preferably butyraldehyde-mono-butylamine or butyraldehydeaniline.  The polymerization of the chloroprene is preferably effected in emulsion, and controlling-agents, emulsifying-agents and antioxidants may be added.  In an example of the preparation of the polymerizate, the chloroprene, containing a small amount of wood rosin, is stirred with a hot solution of sulphur in chlorinated naphthalene, and is then emulsified with water containing ammonium persulphate, the sodium salts of dinaphthyl methane sulphonic acids, and sodium hydroxide, the emulsion being maintained at 40 DEG  C. until the density reaches 1.05.  A dispersion of phenyl-b -naphthylamine in sodium abietate solution neutralized with acetic acid is added, and the product is coagulated in the form of a continuous sheet by freezing on a cooled rotating drum, washed, dried and milled with tetramethyl thiuram disulphide.  The product is mixed with various ingredients, including, if necessary, a solvent such as benzene, toluene, xylene, carbon tetrachloride, trichloromethane, or a hydrogenated substitute for toluene, and is then treated with a mixture of litharge and butyraldehyde amine in proportions of between 10 and 20 by weight of litharge to 2 of butyraldehyde amine, the proportion of the mixture to sulphur-chloroprene polymerizate being between 0.5 and 25 per cent.  A small amount of an alcohol or ketone, volatile at curing temperature and containing less than five C atoms, e.g. methyl, ethyl or amyl alcohol or acetone, may be added to prevent premature gelation. Compositions described consist of (a) polymerizate, hexamethylene-ammonium-hexamethylene - dithiocarbamate, phenyl - b  - naph - thylamine, carbon black, mineral oil and a solvent; (b) polymerizate, di-o-tolyl-guanidine, phenyl-b -naphthylamine, carbon black, mineral oil and xylene; and (c) polymerizate, phenyl-b -naphthylamine, magnesia, blanc fixe, channel black, zinc oxide and paraffin.  Specification 504,466, [Group IV], is referred to.