Styrenic block copolymers and methods of preparation thereof
AssigneeKraton Corporation
InventorsXavier D.D.J. Muyldermans, Julie Li
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Abstract
A hydrogenated styrenic block copolymer (HSBC) is disclosed comprising, prior to hydrogenation, a polymer block A of at least one vinyl aromatic monomer, a polymer block B of at least one conjugated diene, and a copolymer block C of at least one vinyl aromatic monomer and 1,3-butadiene monomer. The HSBC has a total vinyl aromatic content of 15 to 60 wt. % and an aromatic blockiness index of 20 to 80%. The viscoelastic properties of HSBC show a value of a tan δ peak height of 0.7 to 2, a tan δ peak temperature of −40 to 25° C., and a temperature width value (in ° C.) at half the tan δ peak height of 17 to 40. The HSBC provides improved mechanical properties and can be used in preparation of adhesives and protective films applications.
Claims20
A hydrogenated styrenic block copolymer comprising:
- at least one polymer block A, at least polymer block B, and at least one copolymer block C;
- wherein prior to hydrogenation,
- each polymer block A is derived from a vinyl aromatic monomer,
- each polymer block B is derived from a conjugated diene monomer selected from the group consisting of isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1-phenyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 3-butyl-1,3-octadiene, farnesene, myrcene, piperylene, cyclohexadiene, and mixtures thereof, and
- each copolymer block C is derived from at least one vinyl aromatic monomer and 1,3-butadiene monomer;
- wherein after hydrogenation, the hydrogenated styrenic block copolymer has:
- a hydrogenation level in the polymerized conjugated diene monomer in the polymer block B of greater than 90%;
- a hydrogenation level in the polymerized 1,3-butadiene monomer in the polymer block C of greater than 90%;
- a total vinyl aromatic content of 15 to 60 wt. %;
- an aromatic blockiness index (ABI) of 20 to 80%;
- and
- a rubbery aliphatic methyl index (RAMI) of 10 to 35;
- wherein the hydrogenated styrenic block copolymer is characterized as having:
- a tan δ peak height of 0.7 to 2;
- a tan δ peak temperature of −40 to 25° C.;
- a temperature width value (in ° C.) at half the tan δ peak height of 17 to 40;
- and
- a temperature difference value (in ° C.) between the tan δ peak temperature and a maximum loss modulus peak temperature of 14 to 21, all measurements by Dynamic Mechanical Analysis (DMA) (10 rad/sec.).
Dependencies are inferred from the claim text.