Patent ID: 7960466

Claim:
A method of producing natural rubber masterbatch, comprising a mixing step of mixing a natural rubber latex with a slurry containing water and a carbon black dispersed therein, wherein 10 to 100 weight parts of the carbon black is mixed with 100 weight parts of a natural rubber component in the natural rubber latex and the carbon black satisfies the following conditions: (1) the nitrogen adsorption specific surface area (N 2 SA) thereof is 120 to 149 m 2 /g; (2) the relationship between 24M4DBP oil absorption and N 2 SA is represented by the inequality 15≦24M4DBP-0.375N 2 SA≦38; and (3) the mode (Dst) of aggregates of the carbon black is represented by the inequality Dst≦65 nm and the ratio (ΔD50/Dst) of the half width (ΔD50) of the carbon black aggregates to the mode (Dst) thereof is represented by the inequality ΔD50/Dst≦0.70.