Patent ID: 8461270

Claim:
A copolymer having greater than 50% syndiotactic structure comprising an olefin and an aromatic vinyl compound, wherein a content of a unit derived from the aromatic vinyl compound is from 1 to 99% by mol; a molecular distribution (Mw/Mn) measured by a GPC method is 1.7 or more; in 13 C-NMR measurement, a signal T δδ based on an (olefin-aromatic vinyl compound-olefin) linkage as a node of the copolymer, a signal T βδ based on an (aromatic vinyl compound-aromatic vinyl compound-olefin) linkage, a signal T ββ based on an (aromatic vinyl compound-aromatic vinyl compound-aromatic vinyl compound) linkage as a block linkage of the aromatic vinyl compound, and S δδ based on an (olefin-olefin-olefin) linkage as a block linkage of the olefin are present; an index Θ showing block property of the aromatic vinyl compound component represented by the following relational expression is from 30 to 100%; and a stereoregularity [rrrr] of a repeating unit chain constituted by the aromatic vinyl compound is 80% by mol or more: Θ = I ⁡ ( T ββ + T βδ ) I ⁡ ( T δδ + T γδ + T ββ + T βδ ) × 100 ⁢ ( % ) wherein I(T ββ +T βδ ) represents a sum of intensities of the signal T ββ and the signal T βδ in the 13 C-NMR measurement, and I(T δδ +T γδ +T ββ +T βδ ) represents a sum of intensities of signals T δδ , T γδ , T ββ and T βδ based on all linkages that the aromatic vinyl compound contributes to in the 13 C-NMR measurement, wherein T γδ represents a signal based on an (aromatic vinyl compound-aromatic vinyl compound-olefin-olefin) linkage as a heterogeneous bond or a signal based on an (aromatic vinyl compound-olefin-aromatic vinyl compound-olefin) linkage as a heterogeneous bond.