Process for the preparation of styrene-butadiene rubbers comprising recycled rubber powder

A process for the preparation of a styrene-butadiene rubber comprising micronized recycled rubber powder, said process comprising the following steps:

• (a) preparing a suspension comprising micronized recycled rubber powder, water and at least one surfactant;
• (b) mixing the suspension obtained in step (a) with at least one styrene-butadiene latex to obtain a styrene-butadiene latex comprising micronized recycled rubber powder;
• and
• (c) subjecting the latex obtained in step (b) to coagulation to obtain a coagulated styrene-butadiene rubber comprising micronized recycled rubber powder;
• wherein:
• in step (a) the particle size of said micronized recycled rubber powder is ranging from 0.05 mm to 0.8 mm;
• in step (a) said at least one surfactant is present in an amount ranging from 0.5% by weight to 3% by weight, with respect to the total weight of said recycled rubber powder;
• and
• in step (a) said micronized recycled rubber powder has a concentration in water ranging from 1% by weight to 50% by weight, with respect to the total weight of said water.