Impact absorber composition
AssigneeAsahi Kasei Chemicals Corporation
InventorsYasuhiro Kusanose, Yoshifumi Araki
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Abstract
Provided in this invention is an impact absorber composition comprising a copolymer containing an aromatic vinyl compound, wherein the peak of tan δ of the copolymer obtained from the measurement of the dynamic viscoelasticity is in the range of more than 0° C. to 20° C. or less, the value of tan δ is 0.4 or more in the whole temperature range of 5° C. to 15° C., and the value of tan δ at 15° C. is 0.5 or more.
Claims24
An impact absorber composition comprising a copolymer containing an aromatic vinyl compound, wherein a tan δ peak determined from a measurement of dynamic viscoelasticity (at 1 Hz) of the copolymer is in a range from more than 0° C. to 20° C. or less, a tan δ value of the copolymer is 0.4 or more in a whole temperature range of 5° C. to 15° C., the tan δ value of the copolymer at 15° C. is 0.5 or more, and content of the aromatic vinyl compound in the copolymer containing the aromatic vinyl compound is more than 50% by weight.
A process for producing a copolymer containing an aromatic vinyl compound by anionic polymerization, which comprises:
- a step of polymerizing a copolymer block (S) composed principally of an aromatic vinyl compound and a conjugated diene,
- wherein the step of polymerizing the copolymer block (S) is carried out by supplying the aromatic vinyl compound and the conjugated diene to a polymerization tank for polymerization by changing a ratio of the aromatic vinyl compound to the conjugated diene, or by portioning a monomeric mixture differing in a ratio of the aromatic vinyl compound to the conjugated diene in two or more stages.
Dependencies are inferred from the claim text.