processo para preparação de pó de borracha contendo cargas de negro de fumo, em forma de pó, à base de tipos de borracha que se apresentam em solventes orgánicos, bem como mistura de borracha/carga de escoamento livre e seu emprego

• Main Authors: UDO GOERL, REINHARD STOBER, MATTHIAS SCHMITT, ANDREAS GOUW
• Format: Patent
• Language: Portuguese
• Published: 17.05.2011
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; CHEMISTRY; COMPOSITIONS BASED THEREON; COMPOSITIONS OF MACROMOLECULAR COMPOUNDS; GENERAL PROCESSES OF COMPOUNDING; METALLURGY; ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; USE OF INORGANIC OR NON-MACROMOLECULAR ORGANIC SUBSTANCES ASCOMPOUNDING INGREDIENTS; WORKING-UP

Finely-divided, free-running rubber powder production from carbon black filler (I) and rubber (II) obtained by solution polymerization in organic solvent (III) comprises suspending (I) in water; separating 0.5-20% of (I) as suspension; heating rest to boiling point of (III); adding (II) solution and distilling (III) off; adding retained (I) suspension, 1-15 parts (II) emulsion and acid to pH 2-7 to form (I) coat around each rubber particle; and drying. Production of finely-divided, free-running rubber powder containing carbon black filler (I) and a rubber (II) produced by solution polymerization in an organic solvent (III) comprises: (a) suspending (I) in water, without other additives, by shear-intensive stirring to give a suspension density of 0.5-15%, according to the degree of filling; (b) separating 0.5-20% of (I) as suspension from the rest with respect to the total amount in the finished product; (c) heating the remaining suspension to a temperature corresponding approximately to the boiling point of (III); (d) stirring the (II) solution into the (I) suspension and, in parallel, distilling (III) off at atmospheric pressure or in vacuo, with heating to maintain the temperature at which (III) can vaporize, so that the (II)/(I) composite is changed from a 2-phase to a 1-phase system; (II) is transferred to the aqueous (I) suspension, the composite is formed by removing the organic phase by distillation and the product is a composite in an aqueous 1-phase system; (e) treating the suspension containing the product with the retained (I) suspension, with stirring; (f) treating the suspension from (d) and (e) with a further 1-15 parts (II) emulsion with respect to total (II); (g) adjusting the suspension to pH 2-7 with a Bronsted or Lewis acid, so that an effective separating layer of (I), anchored mechanically, forms around each rubber powder particle; (h) freeing the product from most of the water; and (i) drying the moist product to ≤ 2% residual moisture. An Independent claim is also included for the resultant free-running rubber/filler batches, which contain (II), (I) and optionally other fillers and components.