Blends of styrene-butadiene co-polymers (SBC) with random blocks and SMMA
Polymer composition comprising (a) 33 to 52 wt.-% star-shaped block copolymers (a) comprising terminal vinylaromatic polymer blocks S 1 and S 2 , and random styrene/butadiene copolymer blocks (B/S); and (b) 48 to 67 wt.-% SMMA copolymers (b). Moldings and shaped articles produced thereof have a high clarity and toughness and can be used in the household, appliance and healthcare sector.
1. A polymer composition comprising components (a), (b), and (c):
(a) 33 to 52 wt.-% of at least one star-shaped block copolymer (a) which comprises at least two terminal polymer blocks S 1 and S2 made from vinylaromatic monomers and at least one random copolymer block (B/S) made from 20 to 60 wt.-% vinylaromatic monomer, and from 40 to 80 wt.-% diene, and where the total block copolymer (a) is made from 50 to 85 wt.-% vinylaromatic monomer and from 15 to 50 wt.-% diene;
(b) 48 to 67 wt.-% of at least one copolymer (b) made from 65 to 90 wt.-% vinylaromatic monomer (b11) and 10 to 35 wt.-% methyl methacrylate (b12); and optionally
(c) 0 to 5 wt.-% of one or more additive(s) and/or processing aid (c),
wherein
the total amount of components (a), (b), and (c) is 100 wt.-%;
the star-shaped block copolymer (a) has structures in which the star has at least one branch having the block sequence S 1 -(B/S) 1 -(B/S) 2 and at least one branch having the block sequence S 2 -(B/S) 1 -(B/S) 2 , or in which the star has at least one branch with the block sequence S 1 -(B/S) 1 -(B/S) 2 -S 3 and at least one branch with the block sequence S 2 -(B/S) 1 -(B/S) 2 -S 3 , wherein:
M n of S 1 is from 5,000 to 30,000 g/mol;
M n of S 2 is from 35,000 g/mol to 150,000 g/mol; and
S 3 is a further polymer block made from vinylaromatic monomers with M n being smaller than 2,500 g/mol; and
the random copolymer block (B/S) 1 is made from 40 to 60 wt.-% vinylaromatic monomer and from 40 to 60 wt.-% diene, and the random copolymer block (B/S) 2 is made from 20 to 39 wt.-% vinylaromatic monomer and from 61 to 80 wt.-% diene.
2. The polymer composition according to claim 1 comprising components (a), (b), and (c) in the following amounts:
33 to 50 wt.-% (a),
50 to 67 wt.-% (b), and
0 to 5 wt.-% (c).
3. The polymer composition according to claim 1 comprising components (a), (b), and (c) in the following amounts:
34 to 45 wt.-% (a),
55 to 66 wt.-% (b), and
0 to 4 wt.-% (c).
4. The polymer composition according to claim 1 , wherein the values of the refractive index of components (a) and (b) differ no more than 0.005.
5. The polymer composition according to claim 1 , wherein the copolymers (b) are made from 70 to 85 wt.-% (b11), and 15 to 30 wt.-% (b12).
6. The polymer composition according to claim 1 , wherein the copolymers (b) are made from 74 to 84 wt.-% (b11) and 16 to 26 wt.-% (b12).
7. A process for the preparation of the polymer composition according to claim 1 , prepared by mixing the components (a), (b), and (c).
8. A molding, a fiber, or a foil, comprising the polymer composition according to claim 1 .
9. A method of using a molding, a fiber, or a foil, comprising the polymer composition according to claim 1 in the household, appliance, and healthcare sector.
10. The polymer composition according to claim 1 , wherein the star-shaped block copolymer (a) is of the following structures:
where X is a tetrafunctional coupling agent.
11. The polymer composition according to claim 1 comprising components (a), (b), and (c):
(a) 33 to 52 wt.-% of at least one star-shaped block copolymer (a) which comprises at least two terminal polymer blocks S 1 and S 2 made from styrene and at least one random copolymer block (B/S) made from 20 to 60 wt.-% styrene and from 40 to 80 wt.-% 1,3-butadiene, and where the total block copolymer (a) is made from 50 to 85 wt.-% styrene and from 15 to 50 wt.-% 1,3-butadiene;
(b) 48 to 67 wt.-% of at least one copolymer (b) made from 65 to 90 wt.-% styrene (b11) and 10 to 35 wt.-% methyl methacrylate (b12); and
(c) 0 to 5 wt.-% of one or more additive(s) and/or processing aid (c),
wherein
the total amount of components (a), (b), and (c) is 100 wt.-%;
the star-shaped block copolymer (a) has structures in which the star has at least one branch having the block sequence S 1 -(B/S) 1 -(B/S) 2 and at least one branch having the block sequence S 2 -(B/S) 1 -(B/S) 2 , or in which the star has at least one branch with the block sequence S 1 -(B/S) 1 -(B/S) 2 -S 3 and at least one branch with the block sequence S 2 -(B/S) 1 -(B/S) 2 -S 3 , wherein:
M n of S 1 is from 5,000 to 30,000 g/mol;
M n of S2 is from 35,000 g/mol to 150,000 g/mol; and
S 3 is a further polymer block made from vinylaromatic monomers with M n being smaller than 2,500 g/mol; and
the random copolymer block (B/S) 1 is made from 40 to 60 wt.-% styrene and from 40 to 60 wt.-% 1,3-butadiene, and the random copolymer block (B/S) 2 is made from 20 to 39 wt.-% styrene and from 61 to 80 wt.-% 1,3-butadiene.