BITUMEN COMPOSITIONS AND THEIR PRODUCTION PROCESS Russian patent published in 2002 - IPC

FIELD: road-building materials. SUBSTANCE: process involves blowing of bitumen blend with oxygen-containing gas, bitumen blend including bitumen with penetration rate less than 300 dmm (according to procedure ASTM D5 at 25 C) and thermoplastic rubber in amount less than 3% of the total weight of blend. Bitumen blends of invention, which show good low-temperature characteristics, are applied for pavements. Employed rubber has formula A(AB)_m or (AB)_nX, wherein block A represents predominantly block of poly(monovinylaromatic hydrocarbon) with up to 10% of a comonomer, block B represents predominantly block of poly(conjugated diene) with up to 10% of a comonomer, X residue of multivalent linking reagent, n and m integers equal to or greater than 1. Block copolymer can also be hydrogenized. EFFECT: improved working characteristics. 4 cl, 1 tbl, 4 ex