Rubber compound powders containing large proportion of fillers, method of obtaining them and method of obtaining vulcanisable rubber compounds

摘要

Rubber powder with a high filler content contains filler, preferably precipitated silicic acid, whose surface is modified wi an organosilicate, and/or carbon black. Rubber powder comprises oxidic or preferably silicated filler, preferably precipitated silicic acid used at 250-5000 phr if synthetic or 350-500 if natural, whose surface is modified with an organosilicate of formula (I), (II) or (III) and/or 250-5000 carbon black, the total amount of filler being not above 5000 phr: ((R1n(RO)3-nSi(Alk)m(Ar)p)q)(B) (I) R1n(RO)3-nSi(Alkyl) (II) R1n(RO)3-nSi(Alkenyl) (II) B = SCN, SH, Cl, NH2 (q = 1) or Sx (q = 2); R and R1 = 1-4C alkyl or phenyl; n = 0, 1 or 2; Alk = 1-6C alkyl; m = 0 or 1; Ar = 6-12C arylene; p = 0 or 1 provided that m, n and p are not all 0; x = 2-8; Alkyl = 1-20 (2-8) C hydrocarbon; and Alkenyl = 2-2 (2-8) C hydrocarbon. Independent claims are included for: (a) the preparation of the above finely divided rubber powder by precipitation from aqueous mixtures containing filler in suspension and a rubber aqueous emulsion or solution by the addition of metal salts of group IIa, IIb, IIIa or VIII comprising mixing a polymer latex, emulsion of solution with a suspension prepared by forming a filler suspension of water, silicate compou and/or carbon black of suspension density 0.5-10 (1-7) %, optionally deagglomerating and optionally adding 0.5-10 pts. polyalcoh or polyamines, heating at 25-95 degrees C, adding an organosilicate as above, optionally in the presence of a surface active material, and stirring at 10-60 degrees C, washing to remove acid, drying and grinding; and (b) the preparation of vulcanized rubber mixture by adding the above rubber powder to a rubber mixture as a filler along wi other optional additives.