| 摘要 |
Vulcanizable or vulcanized synthetic rubber is stabilized with a non-resinous condensation product of substantially one mol. of an aliphatic aldehyde with two mols. of a phenol of formula <FORM:0767019/IV(a)/1> wherein R1 is hydrogen or an alkyl radical and R2 and R3 are alkyl radicals (see Group IV (b) for materials used and method of preparation). Synthetic rubbers spec butadiene (or its homologues) alone or with styrene, a -methyl styrene, acrylonitrile, methacrylonitrile, vinyl esters, acrylic or methacrylic acid esters, vinyl pyridine or vinyl carbazole. The rubber and antioxidant may be dry mixed or a colloidal dispersion of the condensate may be added to a rubber latex which is then cast, gelled or coagulated. Rubber compounding ingredients described are sulphur, thiazole, phenol polysulphides, dithiocarbamates, dithiols, nitro- and nitroso-compounds, zinc oxide, stearic acid, pine tar, wax, carbon black, white pigment and ultramarine blue. Specification 708,640, [Group IV (b)], is referred to.ALSO:Non-resinous condensation products are produced by condensing substantially one mol. of an aliphatic aldehyde with two mols. of a phenol of formula: <FORM:0767019/IV(b)/1> wherein R1 is hydrogen or an alkyl radical and R2 and R3 are alkyl radicals. Aldehydes specified are formaldehyde, acetaldehyde, crotonaldehyde, n-butyraldehyde, isobutyraldehyde, aldol, acrolein, propionaldehyde, valeraldehyde, isovaleraldehyde, 2 - ethyl - butyraldehyde, hexanal, heptanal, 2-ethyl-hexanal and 3,5,5-tri-methylhexanal. The hydrocarbon substituent in the phenol may be isopropyl, tert. or sec. butyl, amyl, hexyl, heptyl, octyl, nonyl or decyl or sec.-isoamyl. Condensation preferably takes place in the presence of an acid catalyst such as glacial acetic acid plus conc. hydrochloric acid. The products are useful as antioxidants for vulcanizable or vulcanized natural or synthetic rubber and the examples and tests describe the preparation at room temperature of crystalline and syrupy condensates having molecular weights of from 260 to 370, and the application of same in tyre tread and side wall compositions (see Groups IV (a) and V). Examples 1 and 4 describe the preparation of 2-t-butyl - 5 - isopropylphenol and 2 - t - octyl - 5-isopropylphenol from m-isopropylphenol and t-butyl chloride or di-isobutylene respectively. The mixtures are refluxed in the presence of stannic chloride catalyst and then washed with acid, water and alkali in succession. Specification 708,640 is referred to.ALSO:Vulcanizable or vulcanized rubber is stabilized with a non-resinous condensation product of substantially one mol of an aliphatic aldehyde with two mols of a phenol of formula:- <FORM:0767019/V/1> wherein R1 is hydrogen or an alkyl radical and R2 and R3 are alkyl radicals (see Group IV(b) for materials used and method of preparation). The components may be dry mixed or a colloidal dispersion of the condensate may be added to a rubber latex which is then coagulated. The physical properties are given for tire tread and side wall compositions comprising natural rubber (such as pale crepe rubber) vulcanized in the presence of antioxidants of the invention with ingredients such as sulphur, thiazole, phenol polysulphides, dithiocarbamates, dithiols, nitro- and nitroso-compounds, zinc oxide, stearic acid, pine tar, wax, carbon black, white pigment and ultramarine blue. Specification 708,640 is referred to.
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