| 摘要 |
A process for the preparation of a mixture of linear three-block copolymers which contain from 70 to 80% by weight of styrene units and from 20 to 30% by weight of elastomeric polymer segments based on a conjugated diene, in a total of three stages, specific conditions in respect of the initiator and of the monomers to be polymerized being essential in the individual stages in order to ensure the polymodal structure of the three-block copolymers. After complete reaction of the monomers, the mixture of the living polymers is treated with proton-active compounds, and the mixture of the block copolymers is isolated by removing the solvent. The compositions obtained by the novel process are transparent and clear and have good mechanical properties. They are furthermore readily processable by the methods conventionally used for thermoplastics. The compositions are particularly suitable for the production of moldings and of packaging materials.
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