Patent GB-598322-A (GB)
Title: Improvements in or relating to the stabilization of synthetic rubber latices
IPC: C08K5/13
Filed: 1945-06-20
Abstract: Synthetic rubber latices are stabilized by the addition of a ditertiary alkyl phenol.  The preferred stabilizers are the ditertiary butyl and ditertiary amyl derivatives of o-, m- and p-cresol.  The latices may be those obtained by the copolymerization in aqueous emulsion of butadiene-1,3; isoprene; piperylene; dimethyl butadiene; and methyl pentadiene; in admixture with styrene; alpha methyl styrene; para methyl styrene; alpha methyl para methyl styrene; halogenated styrenes such as chloro- or bromo-styrene; acrylonitrile; methacrylonitrile; acrylic acid and methacrylic acid esters such as methyl acrylate and methyl methacrylate; fumaric acid esters such as ethyl fumarate; and unsaturated ketones such as methyl vinyl ketone, and methyl isopropenyl ketone.  The latices may be prepared by emulsifying the reactants in water in the presence of a water-soluble soap such as alkali metal or ammonium oleates, stearates or palmitates; and surface active agents such as salts of alkylated naphthalene sulphonic acids, fatty alcohol sulphates, salts of aliphatic and olefinic sulphonic acids and acid addition salts of high molecular alkyl amines; and polymerization catalysts such as benzoyl peroxide, hydrogen peroxide, and alkali metal or ammonium perborates or persulphates; and a polymerization modifier such as a dialkyl xanthogen disulphide, or an aliphatic mercaptan containing at least 7 carbon atoms in an aliphatic linkage, such as heptyl, octyl, decyl, dodecyl, lauryl or benzyl mercaptan.  The stabilizer is preferably employed in the form of a dispersion obtained by grinding the phenol in the presence of a soap or aromatic sulphonate and a protective colloid such as glue with or without a preservative such as that known as "Collatone."  Alternatively, the stabilizers may be dissolved in an aromatic solvent or an alcohol with at least 4 carbon atoms. Diisobutyl phenol sulphide may also be added.ALSO:Synthetic rubber latices are stabilized by the addition of a ditertiary alkyl phenol.  The preferred stabilizers are the ditertiary butyl and ditertiary amyl derivatives of o-, m-, and p-cresol.  The latices may be thus obtained by the polymerisation in aqueous emulsion of butadiene 1, 3; isoprene; piperylene; dimethyl butadiene; and methyl pentadiene; either singly or in admixture with styrene; alpha methyl styrene; para methyl styrene; alpha methyl para methyl styrene; halogenated styrenes such as chloro-, or bromo-styrene; acrylonitrile; methacrylonitrile; acrylic acid and methacrylic acid esters such as methyl acrylate and methyl methacrylate; fumaric acid esters such as ethyl fumarate; and unsaturated ketones such as methyl vinyl ketone, and methyl isopropenyl ketone.  Up to 7 per cent., though usually from 0.1 to 2.0 per cent. of the stabilizer, is employed, preferably in the form of a dispersion obtained by grinding the phenol in a ball or colloid mill in the presence of a dispersing agent such as soap or aromatic sulphonates, and a protective colloid such as glue with or without a preservative such as that known as "Collatone."  Alternatively the stabilizer may be dissolved in a solvent such as an aromatic hydrocarbon or an alcohol with at least 4 carbon atoms.  Di-isobutyl phenol sulphide may also be added as an auxiliary stabilizer.  The stabilized latex may be concentrated by adding ammonium chloride, warming to 60 DEG C, adjusting the pH to 9.5 and then creaming with ammonium alginate.