Fina Research, S.a.

Jean-Philippe Hallet

Emmanuel Lanza

Bernard Haveaux

Thierry Christian Coupin

Frans Maurice Defoor

Andr&eacute; Noiret

Andre Noiret

The present invention relates to bituminous compositions used for roofing and waterproofing membranes or material comprising asymmetrical coupled polyvinyl aromatic-polydiene block copolymers having improved physical properties over broader ranges of service temperatures than those obtained from bituminous compositions prepared with symmetrical block copolymers of similar type. The asymmetry of the copolymer which is characterised by polyvinyl aromatic endblocks of at least two different molecular weights, one high and one low, ensures improved physical performance to roofing and waterproofing membranes made from such compositions.

Bituminous compositions containing coupled copolymers

An elastomer is blended with bitumen, an alkaline compound is then added which is soluble in the bitumen, and to this mixture is added 0.01 to 0.1% by weight of a mixture of vulcanizing agents comprising elemental sulphur and a sulphur-containing derivative of the form: ##STR1## where R.sub.1 and R.sub.2 are C.sub.1 to C.sub.4 alkyl radicals or, together R.sub.1 and R.sub.2 have the formula ##STR2## and where M, which is optional, is Zn, Ba or Cu.

Process for preparing bitumen/rubber compositions

The present invention relates to bituminous compositions used for roofing and waterproofing membranes or material comprising asymmetrical linear polyvinyl aromatic-polydiene block copolymers having improved physical properties over broader ranges of service temperatures than those obtained from bituminous compositions prepared with symmetrical block copolymers of similar type. The asymmetry of the copolymer which is characterised by polyvinyl aromatic endblocks of at least two different molecular weights, one high and one low, ensures improved physical performance to roofing and waterproofing membranes made from such compositions.

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Woluwe-St-Pierre, Belgium

Jean-Philippe Hallet