GB1361540A - Methods of preparing pulverulent mixtures of elastomers and coll agenic proteins and products thus obtained - Google Patents

Abstract

1361540 Protein/rubber mixtures CENTRE TECHNIQUE DU CUIR 28 April 1972 [6 May 1971] 19845/72 Headings C3H C3P and C3Q Pulverulent mixtures of collagenic proteins with natural or synthetic rubber are produced by the following process sequence: (1) proteinic raw material, e.g. cow hide waste, which has been ground and partially degreased with hot water to reduce its fatty substance content to 5-35 wt. per cent, is treated at a temperature not exceeding 30‹ C. with a chlorinated acid, e.g. chloroacetic acid, and simultaneously to mechanical mixing, the acid concentration being in the range 0À5-2À0 molar; (2) the dispersion thus obtained, having a dry substance content of 5-25 wt. per cent, is diluted with water to reduce the solid particle concentration to 0À5-10 wt. per cent; (3) the diluted dispersion is treated continuously or discontinuously, for 15-45 seconds at a temperature not exceeding 30‹ C., in a homogenizing grinder having its blades driven at supersonic frequencies within the range 3500 Hz to 560 kHz; (4) adjusting the homogenized dispersion to pH 3-5 and then mixing it at 20-60‹ C. with either a stabilized or unstabilized natural rubber latex or a synthetic rubber latex which has been stabilized by alkali, the proportions being 10- 100 parts protein to 100 parts rubber; (5) coagulating the mixture, and simultaneously tanning the proteins, by treatment with an aldehyde, e.g. formaldehyde or glutaraldehyde, or with a metal salt, e.g. basic chromium sulphate, potassium alum, or aluminium sulphate; and (6) filtering, washing and drying the mixture. The mixture obtained in step (4) may be homogenized prior to step (5). In examples, the rubber latex used is natural rubber, SBR or nitrile rubber, and the rubber/ pretein product mixtures are compounded with conventional rubber additives and vulcanized.