Patent GB-689589-A (GB)
Title: Age resisting non-staining rubber composition and method of producing same
IPC: C08K5/13
Filed: 1950-07-04
Abstract: GR-S rubber is protected from oxidation by the incorporation of the non-resinous reaction product of 3 to 4 moles. of an aliphatic aldehyde and 6 moles. of an alkylphenol of the formula <FORM:0689589/IV (a)/1> wherein R is an alkyl or substituted alkyl radical containing 3 to 10 carbon atoms and R1 is hydrogen, an alkyl radical or substituted alkyl radical, such radical containing 1 to 10 carbon atoms.  In examples are described the preparation of the products as viscous syrups by reacting 2 mols. of 2-tert.-butyl-5-methylphenol with 1 mole. of formaldehyde and reacting 2 moles. of 2,4-di-tert.-butyl-5-methylphenol with 1.32 moles. of formaldehyde, the incorporation of such products into dispersions made by emulsion copolymerization of 1,3-butadiene and styrene mixtures containing at least 50 per cent of butadiene, coagulation of the copolymers together with the product, and drying the GR-S rubbers so obtained, and the use of such GR-S rubbers in white mixes which are then vulcanized.ALSO:A non-resinous reaction product of 3 to 4 moles of an aliphatic aldehyde and 6 moles of an alkylphenol of the formula <FORM:0689589/IV (b)/1> wherein R is an alkyl or substituted alkyl radical containing 3 to 10 carbon atoms and R1 is hydrogen, an alkyl radical or a substituted alkyl radical, such radical containing 1 to 10 carbon atoms is incorporated into rubber as a non-discolouring antioxidant therefor.  Examples are concerned with making the products by reacting paraldehyde, formalin, and formaldehyde solutions with 2-tert.-butyl-5-methylphenol, 2-tert.-octyl-5-methylphenol, 2,4-di - tert. - butyl - 5 - methylphenol, 2,4 - di - amyl-5-methylphenol, and 2,4-di-(a ,a -dimethylbenzyl)-5-methylphenol in the presence of hydrochloric acid or glacial acetic acid and concentrated sulphuric acid, or of sodium hydroxide, neutralizing where desired, taking up the reaction product with benzene, benzene-alcohol, ether, petroleum ether, or petroleum etherether, removing the solvent, and purifying by recrystallizing from a solvent or drying over anhydrous potassium carbonate.  Other aldehydes which may be used are crotonaldehyde, butyraldehyde, isobutyraldehyde, propionaldehyde, valeraldehyde, isovaleraldehyde, 2-ethylbutyraldehyde.ALSO:Vulcanizable rubber is protected from discoloration and oxidation by the incorporation of the non-resinous reaction product of 3 to 4 moles of an aliphatic aldehyde and 6 moles of an alkylphenol of the formula <FORM:0689589/V/1> wherein R is an alkyl or substituted alkyl radical containing 3 to 10 carbon atoms and R1 is hydrogen, an alkyl radical or a substituted alkyl radical, such radical containing 1 to 10 carbon atoms.  The rubber containing product may be vulcanized by sulphur, with or without an accelerator, by sulphur doners such as phenol polysulphides or dithiocarbamates, or by cross-linking agents such as dithiols, nitro-and nitroso-compounds.  Examples are concerned with preparation of the products by reaction of paraldehyde, formalin, and formaldehyde solutions and 2-tert.-butyl-5-methylphenol, 2-tert.-octyl-5-methylphenol, 2,4-di-tert.-butyl-5-methylphenol, 2,4-di-amyl-5-methylphenol, and 2,4-di(a ,a -dimethyl-benzyl)-5-methylphenol, and with testing these products in a culcanized tyre white sidewall mix containing pale cr<\>zepe natural rubber, in a rubber coagulated from a dispersion of GR-S of 75 per cent of butadiene and 25 per cent of styrene, and in a vulcanized white mix containing such GR-S.