| 摘要 |
The hot-melt composition comprises, per 100 parts by weight of the mixture A + B + C, up to 40 parts by weight of at least one polymer D exhibiting an at least partial elastomeric character and chosen from D1 triblock polymers based on a styrene-related monomer and a diene and D2 copolymers containing from 55 to 85 % by weight of units derived from ethylene and from 15 to 45 % by weight of units derived from at least one unsaturated comonomer chosen from alkyl (meth)acrylates containing from 4 to 22 carbon atoms and vinyl esters of acids containing from 1 to 22 carbon atoms. The process of preparation consists in that, during a first stage, of short duration and performed with intense stirring at a temperature of between 180 DEG C and 220 DEG C, the norbornene polymer A, its plasticiser C and at least a proportion of the tackifying resin B are mixed, then the homogeneous mixture obtained is cooled, then, during a second stage, of longer duration than the first one and performed with moderate stirring at a temperature of between 110 DEG C and 140 DEG C, the polymer D and, where appropriate, the remainder of the tackifying resin B are added.
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