A bitumen and elastomers and their application to the damping of vibrations

摘要

An elastomeric bituminous composition possessing vibration dampings properties comprises 70 to 95 per cent by weight of a bitumen having a penetration index between +1 and +7, and 5 to 30 per cent by weight of an elastomer, for example a styrene/butadiene/styrene block copolymer. Preferably, the bitumen has a penetration at 25oC of between 100 and 250 tenths of a millimetre, more preferably between 140 and 200 tenths of a millimetre. The bitumen may be obtained by oxidation in the presence of a catalyst of an atmospheric distillation residue, or a vacuum distillation residue, of a crude oil or a mixture of the two, the preferred catalyst being orthophosphoric acid. The composition is prepared by dissolving or dispersing the polymer in the bitumen at a temperature in the range 180 to 250oC. The composition may be used in sound damping structures.