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AssigneeElf Atochem S. A.
InventorPascal Nicol
Estimating the term…
The invention relates to a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3)-B.sub.2 ].sub.m -X-[B.sub.2 (B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents a polyfunctional radical resulting from a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of resulting from vinylaromatic monomer, characterized in that the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer. The invention also relates to the process for obtaining this copolymer. The compositions comprising this copolymer and crystal polystyrene have noteworthy mechanical properties and transparencies.
A composition comprising crystalline polystyrene and a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3)-B.sub.2 ].sub.m -X-(B.sub.2 -(B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents the polyfunctional residue of a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4 and is also equal to the degree of functionality of the radical X, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of polymerized vinylaromatic monomer units, wherein the vinylaromatic moleties provide from 60 to 90% by weight of the total mass of the said star block copolymer, the conjugated diene moleties provide from 40 to 10% by weight of the total mass of the said star block copolymer, and the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said block copolymer.
A composition comprising crystalline polystyrene and a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3) B.sub.2 ].sub.m -X-[B.sub.2 -(B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents the polyfunctional residue of a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4 and is also equal to the degree of functionality of the radical X, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.2 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of polymerized vinylaromatic monomer units, wherein the vinylaromatic moleties provide from 60 to 90% by weight of the total mass of the said star block copolymer and the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer.
A composition comprising crystalline polystyrene and a star block copolymer of the formula [S.sub.1 -S.sub.2 -(B.sub.1 /S.sub.3) B.sub.2 ].sub.m -X-[B.sub.2 -(B.sub.1 /S.sub.3)-S.sub.2 ].sub.n in which X represents the polyfunctional residue of a coupling agent, m and n represent non-zero integers such that m+n is equal to 3 or 4 and is also equal to the degree of functionality of the radical X, S.sub.1 and S.sub.2 each represent a block of a polymer containing at least one vinylaromatic monomer, B.sub.1 represents a block of a polymer containing at least one conjugated diene, (B.sub.1 /S.sub.3) represents a block of a statistical copolymer containing at least one vinylaromatic monomer and at least one conjugated diene, 40 to 75% by weight of (B.sub.1 /S.sub.3) consisting of polymerized vinylaromatic monomer units, wherein the conjugated diene moieties provide from 40 to 10% by weight of the total mass of the said star block copolymer and the sum of the mass of the blocks B.sub.2 contains more than 40% by weight and less than 90% by weight of the total mass of the conjugated diene contained in the said star block copolymer.
Dependencies are inferred from the claim text.