Perfectionnements aux procédés d'élaboration, notamment de soufflage, des bitumes, et aux bitumes.

摘要

Blowing with air to reduce penetration and raise the softening pt. is carried out in presence of a cyclic anhydride (I) of a dicarboxylic acid derived from a polycyclic hydrocarbon, >=1 ring of which is satd. (I) is pref. bicyclo 2.2.1 -hept-5-ene 2,3-dicarboxylic anhydride its methyl-substd. or saturated derivs. or its condnsn. products with cyclopentadiene or other diene. Alternatively (I) has a naphthalene or anthracene configuration. Amount added is 0.1-10 wt.%. Blowing times are reduced, giving increased output, without affecting the ageing performance of the bitumen in use e.g. for road building.