Patent GB-622518-A (GB)
Title: Process for producing pigmented rubber
IPC: C08J3/215
Filed: 1947-03-18
Abstract: Pigmented synthetic rubber is obtained by colloidally dispersing pigment particles in water with the aid of a dispersing agent, flocculating by the addition of water-soluble salt electrolyte adapted to render the dispersing agent substantially completely inactive, mixing the resultant suspension of pigment particles with a synthetic rubber latex and thereafter coagulating the latex.  The preferred pigment is a carbon black such as channel black, gas black, impingement black, thermal decomposition carbon, furnace black or acetylene black, though zinc oxide, titanium dioxide, lithopone, whiting, clay, blanc fixe, hydrated alumina, precipitated calcium carbonate, iron oxide, ochre, ultramarine blue, cadmium red, cadmium yellow, benzidine yellow, Hansa yellow, phthalocyanines, indanthrene vat pigment dyes or toluidine reds may also be used.  The synthetic rubbers may be neoprene, or copolymers of butadiene with acrylonitrile or styrene.  The preferred dispersing agents are condensation products formed by reacting formaldehyde with naphthalene sulphonic acid, sulpholignins and water-soluble extracts of natural type glucosides such as quebracho extracts, though glue and casein may be used.  A wetting agent may be added to the dispersion to ensure uniformity and to control the size of the particles during flocculation.  Suitable wetting agents of the anionic type are turkey red oil, soluble pine oil, the diamyl ester of sodium sulphosuccinic acid, sulphated glycerylamide water-soluble soaps such as sodium oleate, alkyl naphthalene, sodium sulphonate, and sulphates of higher aliphatic alcohols such as lauryl sulphate; wetting agents of the cationic type are substituted quaternary ammonium compounds such as cetyl methyl dibenzyl ammonium chloride, cetyl trimethyl ammonium bromide or the compounds described in Specification 364,104.  The preferred coagulant is a polyvalent salt such as barium chloride or aluminium sulphate, but other substances which may be used include sodium aluminate, sodium zincate, sodium stannate, sodium silicofluoride, zinc chloride, magnesium chloride, calcium chloride, aluminium acetate, lead subacetate, zinc acetate, magnesium acetate, calcium acetate, primary amine hydrochlorides, aluminium chloride or zinc sulphate, or the following mixtures: sodium chloride, alum, and sulphuric acid; sodium chloride and aluminium chloride; sodium sulphate, aluminium sulphate and sulphuric acid; and sodium acetate, aluminium acetate and acetic acid. Softeners, such as rosin derivatives, pine tar derivatives, asphalt base softeners, and coumarone-indene resins and also solvents such as petroleum hydrocarbons, benzene, Stoddart's solvent, toluene, n-butyl alcohol, trichlorethylene, ethylene dichloride, carbon tetrachloride, turpentine, xylene, terpenes, pinenes, tetralin, decalin and cyclohexene may also be added.ALSO:Pigmented natural or synthetic rubber is obtained by colloidally dispersing pigment particles in water with the aid of a dispersing agent, flocculating by the addition of water-soluble salt electrolyte, adapted to render the dispersing agent substantially completely inactive, mixing the resultant suspension of pigment particles with a rubber latex and thereafter coagulating the latex.  The preferred pigment is a carbon black such as channel black, gas black, impingement black, thermal decomposition carbon, furnace black or acetylene black, though zinc oxide, titanium dioxide, lithopone, whiting, clay, blanc fixe, hydrated alumina, precipitated calcium carbonate, iron oxide, ochre, ultramarine blue, cadmium red, cadmium yellow, benzidine yellow, Hansa yellow, phthalocyanines, indanthrene vat pigment dyes or toluidine reds may also be used.  The synthetic rubbers may be neoprene, or copolymers of butadiene with acrylonitrile or styrene. The preferred dispersing agents are condensation products formed by reacting formaldehyde with naphthalene sulphonic acid, sulpholignins and water-soluble extracts of natural type glucosides such as quebracho extracts, though glue and casein may be used.  A wetting agent may be added to the dispersion to ensure uniformity and to control the size of the particles during flocculation.  Suitable wetting agents of the anionic type are turkey red oil, soluble pine oil, the diamyl ester of sodium sulphosuccinic acid, sulphated glycerylamide water-soluble soaps such as sodium oleate, alkyl naphthalane sodium sulphonate, and sulphates of higher aliphatic alcohols such as lauryl sulphate; wetting agents of the cationic type are substituted quaternary ammonium compounds such as cetyl methyl dibenzyl ammonium chloride, cetyl trimethyl ammonium bromide or the compounds described in Specification 364,104, [Group IV].  The preferred coagulant is a polyvalent salt such as barium chloride or aluminium sulphate but other substances which may be used include sodium aluminate, sodium zincate, sodium stannate, sodium silicofluoride, zinc chloride, magnesium chloride, calcium chloride, aluminium acetate, lead subacetate, zinc acetate, magnesium acetate, calcium acetate, primary amine hydrochlorides, aluminium chloride or zinc sulphate, or the following mixtures: sodium chloride, alum, and sulphuric acid; sodium chloride and aluminium chloride; sodium sulphate, aluminium sulphate and sulphuric acid, and sodium acetate, aluminium acetate and acetic acid.  Softeners, such as rosin derivatives, pine tar derivatives, asphalt base softeners, and coumarone, indene resins and also solvents such as petroleum hydrocarbons, benzene, Stoddart's solvent, toluene, n-butyl alcohol, trichlorethylene, ethylene dichloride, carbon tetrachloride, turpentine, xylene, terpenes, pinenes, tetralin, dicalin and cyclohexene may also be added.