Pneumatic tire and rubber masterbatch

A pneumatic tire, comprising

• at least one tire component selected from the group consisting of a tread, a sidewall, and a tire internal component, the at least one tire component being formed from a rubber composition comprising carbon black, silica, and an emulsion-polymerized rubber that has a soap content of at most 2.5% by mass and an organic acid content of at most 2.5% by mass.

A rubber masterbatch, comprising

• a rubber component derived from an emulsion-polymerized rubber latex, and
• carbon black,
• the rubber masterbatch having an organic acid content of at most 2.0% by mass based on total solids of the rubber masterbatch.

A method for producing a rubber masterbatch, comprising the steps of

• mixing an emulsion-polymerized rubber latex and a carbon black dispersion at a pH of 1.0 to 6.0, and
• separating liquid from the mixed dispersion,
• the method further comprising the step of reducing an organic acid content to at most 2.0% by mass based on total solids of the resulting rubber masterbatch.