To obtain a binder which undergoes less separation of a constituent thermoplastic elastomer and can be kept in an uniform state for a long time even when stored at high temperatures by uniformly mixing the thermoplastic elastomer with carbon black to form a composite before mixing it with asphalt.
100 pts.wt. thermoplastic elastomer, desirably a styrene/butadiene/styrene block copolymer is uniformly mixed with 10-100 pts.wt., desirably 30-80 pts.wt. carbon black to form a complex. The carbon black used should have a particle diameter of 5-100μm, desirably 15-40μm and an N2 adsorption specific surface area of 30-200m2/g, desirably 80-180m2/g. It is desirable that the obtained binder comprises 96.5-70 pts.wt. asphalt, 3-15 pts.wt. thermoplastic elastomer and 0.5-15 pts.wt. carbon black.
OSHIMA NOBUMITSU
IWASAKI SHINICHI
