The invention relates to aA rubber composition has an improved rolling resistance and is based on at least a diene elastomer comprising mainly at least one isoprene elastomer; a reinforcing filler comprising from 10 to 35 phr of carbon black having a BET specific surface area of less than 70 m.sup.2/g, and from 10 to 40 phr of silica; a coupling agent in a content corresponding to a range extending from 5 to 15% by weight relative to the weight of silica; and a crosslinking system; in which composition the total content of carbon black and silica is between 20 and 70 phr, and in which the carbon black to silica weight ratio is greater than 0.3.

A rubber composition is based on at least an elastomeric matrix comprising at most 70 parts by weight, per hundred parts by weight of elastomer, phr, of a polyisoprene and at least 30 phr of a butadiene/styrene copolymer, the butadiene/styrene copolymer exhibiting a content of styrene units of between 20% and 40% by weight, with respect to the total weight of the butadiene/styrene copolymer, a content of trans-1,4-butadiene unit of greater than 65% by weight, with respect to the total weight of the butadiene units, a content of vinyl unit of less than 8% by weight, with respect to the total weight of the butadiene units, and a glass transition temperature of between 60 C. and 35 C.; from 35 to 75 phr of a carbon black exhibiting a BET specific surface of between 90 and 100 m.sup.2/g and a COAN absorption index of between 90 and 100 ml/100 g; and a crosslinking system.

An object of the present invention is to provide a rubber composition which is excellent in cord adhesiveness, steering stability and elongation at break. The present invention relates to a rubber composition for coating a steel cord comprising not less than 0.12 part by mass of zinc benzoate and/or zinc t-butylbenzoate, 0.03 to 0.30 part by mass of fatty acid cobalt salt in terms of cobalt element, and less than 0.5 part by mass in total of a fatty acid having 16 to 22 carbon atoms and a fatty acid derived from the fatty acid cobalt salt which has 16 to 22 carbon atoms based on 100 parts by mass of a rubber component, and a tire having a breaker and/or a carcass obtained by use of the rubber composition for coating a steel cord.

A tire with improved wear resistance, rolling resistance and cohesion, comprises a rubber composition based on at least one elastomeric matrix comprising predominantly a random copolymer comprising ethylene units and conjugated diene units, the mole fraction of ethylene units in the copolymer being within a range extending from 50% to 95%; a peroxide; and a zinc diacrylate derivative in the form of a specific zinc salt; in which composition the contents of zinc diacrylate derivative and of peroxide being such that the ratio of the peroxide content to the zinc diacrylate derivative content is greater than or equal to 0.08; said composition comprising from 5 to less than 65 phr of reinforcing filler; the ratio of the filler content to the zinc diacrylate derivative content being greater than or equal to 1.25.

A rubber composition comprises at least one resin based on: (A1) at least one aromatic compound resulting from the reaction between a reactant of formula ():

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where B represents CHO or CH.sub.2OH, () and a reactant of formula () or

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and (A2) at least one phenolic compound chosen from: (A21) at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functional groups in the meta position with respect to one another, the two positions ortho to at least one of the hydroxyl functional groups being unsubstituted; and/or (A22) at least one aromatic monophenol comprising at least one six-membered aromatic ring bearing a single hydroxyl functional group, the two positions ortho to the hydroxyl functional group being unsubstituted or at least one position ortho to and the position para to the hydroxyl functional group being unsubstituted.

A method for producing a rubber wet masterbatch is disclosed including mixing a carbon-black-containing aqueous-slurry-solution in which a carbon black is dispersed in water with a rubber latex solution to produce a carbon-black-containing aqueous-rubber-latex-solution, solidifying the resultant carbon-black-containing aqueous-rubber-latex-solution to produce a carbon-black-containing rubber solidified product, and dehydrating and drying the resultant carbon-black-containing rubber solidified product to produce a rubber wet masterbatch. In this method, about the carbon-black-containing aqueous-slurry-solution, in carbon black particles in the slurry-solution, the proportion of carbon black particles having a particle diameter of 60 m or more is 35% or less by volume. The particle diameter is based on a measurement of the carbon black particles in the slurry-solution with an image-analytic particle size distribution meter. The method for producing a rubber wet masterbatch can give a vulcanized rubber having excellent abrasion resistance while the rubber has a low exothermicity.

A rubber composition comprises at least one phenol/aldehyde resin based on at least one aromatic polyphenol comprising at least one aromatic ring bearing at least two hydroxyl functions in the meta position relative to one another, the two positions ortho to at least one of the hydroxyl functions being unsubstituted, and at least one aromatic polyaldehyde selected from 1,3-benzenedicarboxaldehyde, 1,4-benzenedicarboxaldehyde and mixtures of these compounds, the rubber composition having a nominal secant modulus at 10% elongation, measured according to standard ASTM D 412, 1998, of greater than or equal to 25 MPa.

A masterbatch manufacturing method is disclosed in which carbon black is added to a liquid and this is agitated to obtain a carbon black slurry; the carbon black slurry and rubber latex are mixed to obtain pre-coagulation rubber latex; and the pre-coagulation rubber latex is coagulated; wherein, at the operation in which the carbon black slurry is obtained, dispersion time from the start of agitation to the end of agitation is not less than 5 times, but not greater than 40 times. A particle diameter reduction relaxation time v may be found by plotting measurement results on a planar graph in such fashion that elapsed time t (minutes) since the start of agitation is plotted on the horizontal axis, and particle diameter f (m) of carbon black is plotted on the vertical axis, to obtain a best-fit solution.

The present invention relates to an aqueous, solids-containing dipping bath composition for treating reinforcing inserts for rubber products comprising the following components or consisting of these components, (A) at least one blocked MDI mixture, the MDI mixture comprising MDI oligomers of formula (I), n being a whole number from 1 to 8, and MDI monomers; (B) at least one latex; (C) at least one compound selected from the group consisting of polyacrylates, lignin derivatives and mixtures hereof; and (D) possibly at least one additive; the dipping bath composition being essentially free of epoxides, and the dipping bath composition being essentially free of resorcinol, formaldehyde and the reaction products thereof.

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The present invention relates to an aqueous, solids-containing dipping bath composition for treating reinforcing inserts for rubber products comprising the following components or consisting of these components, (A) at least one blocked MDI mixture, the MDI mixture comprising MDI oligomers of formula (I), n being a whole number from 1 to 8, and MDI monomers; (B) at least one resorcinol-formaldehyde latex; and (C) possibly at least one additive, wherein the dipping bath composition is essentially free of epoxides.

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