Patent GB-666640-A (GB)
Title: A process for stabilising products formed by the reaction of polydienes with sulphur dioxide
IPC: D06M13/432
Filed: 1948-07-09
Abstract: Reaction products of polydienes with sulphur dioxide are stabilized by contacting them with solutions of compounds containing the group ­C-NRR1 or =C=NR11, in which R, R1 and R11 are hydrogen or the same or different hydrocarbon radicals, the hydrogen atoms of which may be substituted by other atoms or radicals, the presence of oxidizing nitrogen-oxygen radicals in the compounds being avoided.  The polydienes are unsaturated polymers, copolymers of conjugated dienes of 4 to 6 carbon atoms and have a molecular weight above 5000. Examples are polymers of butadiene, pentadiene, methyl and dimethyl butadienes, copolymers of mixtures of these and of one or more with alkenes, e.g. isobutene, or vinyl compounds, e.g. styrene, vinyl chloride, vinyl esters, acrylic and methacrylic acids, acrylonitrile and methacrylonitrile.  Products in which compounds of molecular weight below 5000 are simultaneously reacted with sulphur dioxide, as described in Specification 659,083, are also included.  Examples of stabilizers are aliphatic and aromatic primary, secondary and tertiary amines, e.g. heptadecyl and octadecyl amines, a -naphthylamine, p-phenylene diamine-benzidene, triamino benzene, cetyl aniline, diphenylamine, N - phenyl - b  - naphthylamine, methyl tert.-amyl aniline, ethyl butyl and ethyl octyl aniline, ethyl cyclohexyl aniline, triphenylamine; amino acids and elcohols, e.g. triethanolamine; acid amides, e.g. acetamide, stearic acid amide, benzamide, acetanilide; urea, N,N- and N,N1-diphenyl urea, thiourea, N,N- and N,N1-diphenyl thiourea, N,N- and N,N1-diphenyl guanidine; amides of dithio acids, e.g. tetramethyl thiuram disulphide; zinc dimethyl dithiocarbamate; amidines; urethanes and thiourethanes; carbo-di-imides, e.g. diphenyl and diallyl carbo-di-imides, p,p1-dimethyl diamino diphenyl carbo-di-imide; heterocyclic nitrogen compounds, e.g. hexamethylene tetramine, melamine, phenyl melamine, (methyl-2-dodecyl)-pyridine, thiazole, mercapto-benzimidazole; halogen amines, e.g. monochlorurea, quinone dichlorimide; dicyanodiamide; quaternary ammonium compounds, e.g. cetyl pyridinium chloride.  In some cases the stabilizers can be used in the form of polymers or copolymers.  The stabilizers may be applied by soaking threads or other objects of the reaction product in a stabilizer solution, preferably when the product is still in the swollen state of its production, or it may be added to the liquid in which the product is formed.  The stabilizer may also be added to take part in the reaction producing the products, for which purpose compounds containing an alkenyl group are essential.  The adhesion may also be improved by heating after application or during incorporation of the stabilizer, and by reacting the stabilized products with compounds such as formaldehyde or iso-cyanates.  Combinations of stabilizers may be used, at least two of the group of hexamethylene tetramine and its derivatives, melamine and its derivatives and urea or thiourea and their derivatives including dicyanodiamide, being very effective. The stabilization is against the separation of sulphur dioxide and in some cases is effective against the influence of light.  The invention is exemplified with reaction products of rubber and sulphur dioxide.