RUBBER COMPOSITION AND STYRENE RESIN COMPOSITION USING THE SAME

Embodiments of the present invention provide a rubber composition in which solution viscosity and cold flow are improved. The rubber composition according to the embodiments of the present invention may include 20 to 90 wt % of a polybutadiene (A) produced by a metallocene catalyst, having: a cis-1,4-structure in microstructure being 65 to 95 mol %, a vinyl-1,2-structure in microstructure being 4 to 30 mol %, and a weight average molecular weight (Mw) being 2×105 to 1×106.The rubber composition further includes 10 to 80 wt % of polybutadiene (B) having: a Mooney viscosity (ML1+4, 100° C.) being 60 or less, a 5 wt % of styrene solution viscosity (St-cp) being 20 to 110; and St-cp/ML1+4 being 1.0 to 2.5. A total content of the polybutadiene (A) and the polybutadiene (B) is 60 to 100 wt %.