Powders of rubber mixable has a dry basis, from solutions of rubber and their method of obtaining

摘要

Homogeneous, storage-stable, dry-blendable, hydrocarbon solution non-polar rubber powders having a DSV from about 1.5 to about 7.0 (100 parts) containing carbon black, are prepared by sequentially grinding carbon black (60-90 phr) in water; mixing at a temperature of 20.degree. - 100.degree.C the resulting composition with a hydrocarbon solution of non-polar rubber, about 5 - 25% (w/W), to form a liquid two phase dispersion of (a) hydrocarbon, solvent, carbon black, and rubber, and (b) water; stripping the liquid dispersion of solvant by adding, at a rate of between about 360 - 1270 g./min. the dispersion to vigorously stirred hot water (85 - 120.degree.C) in the presence of at least one foam inhibiting surfactant selected from the group consisting of (a) low-foaming nonionic polyether alcohols with blocked terminal hydroxyl group (0.01 - 5.0 phr), and, (b) cationic tetraalkylammonium salts having more than 25 carbon atoms in the cation thereof (0.01 5.0 phr), to produce powder; and drying the powder to produce a homogeneous, clean and free-flowing powder having a mean particle size from 0.8 to 1.5 mm., with about one-half of the particles having a particle size greater than 1.0 mm. Totally compounded rubber powders can also be produced by dry-blending, powder compounding, for about 2.5 to about 3.5 min. at 1000 5000 r.p.m., the solution rubber powder obtained with from about 45 to about 60 phr oil, and, from about 0.1 to about 20 phr, collectively, of at least one pigment, at least one preservative and at least one curative. Utility for the totally compounded solution rubber powder blend is found in the production of, for exemple, injection molded articles, extruded exterior coatings in electric cable construction, tire construction, and, the preparation of gaskets for hose and pipe which can be utilized in both automotive and home construction.