METHOD FOR PRODUCING RUBBER WET MASTER BATCH, METHOD FOR PRODUCING RUBBER COMPOSITION, AND METHOD FOR PRODUCING TIRE

摘要

The objective of the present invention is to provide a method for producing a rubber wet master batch that serves as a starting material for a vulcanized rubber having excellent fatigue properties, low heat generation properties and tensile characteristics. A rubber wet master batch is produced by a method that comprises: a step for preparing a latex that has a magnesium content of 150 ppm or less; a step for forming a mixed liquid; and a step for obtaining a coagulum by causing coagulation of the mixed liquid. The latex contains rubber particles having a 90% volume particle diameter of 2 μm or less. The step for forming a mixed liquid comprises a step for mixing a latex and a dispersion solvent. The step for forming a mixed liquid additionally comprises a step for mixing a slurry containing a filler with a latex solution that is obtained in the step for mixing a latex and a dispersion solvent. The step for obtaining a coagulum comprises a step for separating the coagulum and a waste liquid from each other. This method for producing a rubber wet master batch satisfies the following formula I. a/b ≥ 65 (formula I) (In formula I, a represents the COD value (mg/L) of the waste liquid; and b represents the content (mass%) of the rubber fraction in the mixed liquid.)