Phase-separating block or graft copolymers comprising incompatible hard blocks and moulding compositions having a high stiffness
A block copolymer or graft copolymer with weight-average molar mass M w of at least 100 000 g/mol, comprising a) at least one block S composed of from 95 to 100% by weight of vinylaromatic monomers and from 0 to 5% by weight of dienes, and b) at least one copolymer block (S/B) A composed of from 63 to 80% by weight of vinylaromatic monomers and from 20 to 37% by weight of dienes, with glass transition temperature Tg A in the range from 5 to 30° C., where the proportion by weight of the entirety of all of the blocks S is in the range from 50 to 70% by weight, based on the block copolymer or graft copolymer, and also mixtures thereof, and their use.
1. A block copolymer or graft copolymer, comprising
a) at least one block S comprising from 95 to 100% by weight of vinylaromatic monomers and from 0 to 5% by weight of dienes, and
b) at least one copolymer block (S/B) A comprising from 63 to 80% by weight of vinylaromatic monomers and from 20 to 37% by weight of dienes, with a glass transition temperature Tg A in the range from 5 to 30° C., and
c) optionally at least one copolymer block (S/B) B comprising from 20 to 60% by weight of vinylaromatic monomers and from 40 to 80% by weight of dienes, with a glass transition temperature Tg B in the range from 0 to −110° C.,
wherein
the proportion by weight of the entirety of all of the blocks S is in the range from 50 to 70% by weight, based on the block copolymer or graft copolymer and the proportion by weight of the entirety of all of the blocks (S/B) A and (S/B) B is in the range from 30 to 50% by weight, based in each case on the block copolymer or graft copolymer; wherein if component c) is present the block copolymer has a linear structure having the block sequence S 1 -(S/B) A -S 2 -(S/B) B -S 3 and if component c) is not present the block copolymer has a linear structure having the block sequence S 1 -(S/B) A -S 2 -(S/B) A -S 3 where each of S 1 , S 2 , and S 3 is a block S; and wherein the proportion by weight of blocks S 1 and S 2 , based on the block copolymer, is from 50% to 67% by weight and the total weight-average molar mass M w of the block copolymer or graft copolymer is in the range from 260,000 to 350,000 g/mol.
2. The block copolymer or graft copolymer according to claim 1 , in which component c) is present.
3. The block copolymer or graft copolymer according to claim 2 , wherein the ratio by weight of the copolymer blocks (S/B) A to the copolymer blocks (S/B) B is in the range from 80:20 to 50:50.
4. A mixture, comprising
K1) from 20 to 95% by weight of a block copolymer or graft copolymer according to claim 1 , and
K2) from 5 to 80% by weight of General Purpose Polystyrene (GPPS) or impact-resistant polystyrene (HIPS), and
K3) from 0 to 50% by weight of a block copolymer which differs from K1 and is composed of vinylaromatic monomers and dienes.
5. The mixture according to claim 4 , which comprises from 10 to 50% by weight of a block copolymer as component K3, where this block copolymer comprises
a) at least one block S comprising from 95 to 100% by weight of vinylaromatic monomers and from 0 to 5% by weight of dienes, and
b) at least one homopolydiene (B) or copolymer block (S/B) B comprising from 0 to 60% by weight of vinylaromatic monomers and from 40 to 100% by weight of dienes, with glass transition temperature Tg B in the range from 0 to −110° C.,
wherein the proportion by weight of the entirety of all of the blocks S is in the range from 25 to 90% by weight, and the proportion by weight of the entirety of all of the blocks (S/B) B is in the range from 10 to 75% by weight, based in each case on the block copolymer.
6. The mixture according to claim 4 , which comprises from 10 to 30% by weight of a block copolymer as component K3, where this block copolymer comprises
a) at least one block S comprising from 95 to 100% by weight of vinylaromatic monomers and from 0 to 5% by weight of dienes, and
b) at least one copolymer block (S/B) B comprising from 20 to 60% by weight of vinylaromatic monomers and from 40 to 80% by weight of dienes, with a glass transition temperature Tg B in the range from 0 to −80° C.,
where the proportion by weight of the entirety of all of the blocks S is in the range from 25 to 70% by weight, and the proportion by weight of the entirety of all of the blocks (S/B) B is in the range from 30 to 75% by weight, based in each case on the block copolymer.
7. A foil or molding for the packaging of electronic components comprising the mixture according to claim 4 .
8. A blister pack, pot, or extruded hollow profile for the packaging of electronic components comprising the mixture according to claim 4 .
9. The block copolymer or graft copolymer according to claim 1 , wherein component c) is not present.
10. The block copolymer or graft copolymer according to claim 1 , wherein the at least one copolymer block (S/B) A comprises from 70 to 75% by weight styrene units and from 25 to 30% by weight of butadiene units.