Polymer modified bitumen, useful for road surfacing, comprises specific amount of block copolymer comprising triblock poly(styrene-butadiene-styrene) copolymer and diblock poly(styrene-butadiene)copolymer

摘要

A polymer modified bitumen comprises bitumen and 1-3 wt.% of a block copolymer comprising 10-30 wt.% of a triblock poly(styrene-butadiene-styrene) copolymer having an average polystyrene content of 25-35 wt.% and mol. wt. of 100,000-150,000 and 70-90 wt.% of a diblock poly(styrene-butadiene)copolymer (B) having an average polystyrene content of 25-35 wt.% and a mol. wt. that is one-third to two-thirds that of component (A). A polymer modified bitumen comprises bitumen and a block copolymer composition, whereby the bitumen and a block copolymer composition whereby the bitumen has a penetration value of 30-70 dmm at 25 [deg]C, a ring and ball softening point of 50-60 [deg]C and asphaltene content of 10-20 wt.%. The block copolymer composition is added in an amount of 1-3 wt.% and comprises 10-30 wt.% of a triblock poly(styrene-butadiene-styrene) copolymer (A) having an average polystyrene content of 25-35 wt.% and mol. wt. of 100,000-150,000 and 70-90 wt.% of a diblock poly(styrene-butadiene)copolymer (B) having an average polystyrene content of 25-35 wt.% and a mol. wt. that is one-third to two-thirds that of component (A), such that the modified bitumen is a compatible mixture having a ring and ball softening point of 55-63 [deg]C, a penetration value of 20-60 dmm at 25 [deg]C and elastic return deformation of at least 50% at 25 [deg]C. An independent claim is included for an asphalt composition comprising 4-9 pts of the above bitumen per 100 pts of additive material.