ABS molding composition having improved crack and chemical resistance and its use

1. A thermoplastic molding composition for use in hydrofluoro olefin containing areas comprising components A, B, C, and D:

(A) 10 to 35 wt.-% of a graft rubber copolymer A obtained by emulsion polymerization and built up from:

(a 1 ) 30 to 90 wt.-%, based on (A), of at least one graft base (a 1 ) made from:

(a 11 ) 70 to 98 wt.-%, based on (a 1 ), of at least one diene, and

(a 12 ) 2 to 30 wt.-%, based on (a 1 ), of at least one monomer selected from the group consisting of styrene, α-methylstyrene, acrylonitrile, methacrylonitrile, and methyl methacrylate, and

(a 2 ) 10 to 70 wt.-%, based on (A), of a graft (a 2 ), grafted onto the graft base and built up from:

(a 21 ) 65 to 95 wt.-%, based on (a 2 ), of at least one vinylaromatic monomer,

(a 22 ) 5 to 35 wt.-%, based on (a 2 ), acrylonitrile and/or methacrylonitrile, and

(a 23 ) 0 to 20 wt.-%, based on (a 2 ), of at least one monomer selected from the group consisting of C 1 -C 4 -alkyl(meth)acrylates, maleic anhydride, N-phenyl maleimide, N-cyclohexyl maleimide, and (meth)acrylamide;

(B) 50 to 70 wt.-% of at least one copolymer B made from:

(b 1 ) 50 to 95 wt.-% of at least one vinylaromatic monomer,

(b 2 ) 5 to 50 wt.-% of acrylonitrile and/or methacrylonitrile, and

(b 3 ) 0 to 20 wt.-% of one or more of the monomers as described for (a 23 );

(C) 4 to 20 wt.-% of at least one elastomeric block copolymer C made from:

(c 1 ) 15 to 65 wt.-%, based on (C), of at least one diene, and

(c 2 ) 35 to 85 wt.-%, based on (C), of at least one vinylaromatic monomer, which block copolymer C comprises:

i) at least two blocks S which have polymerized units of vinylaromatic monomer (c 2 ), a glass transition temperature T g above 25° C. and form a hard phase, and

ii) at least one elastomeric block B/S (soft phase) which contains both polymerized units of vinylaromatic monomer (c 2 ) and diene (c 1 ), has a random structure, a glass transition temperature T g of from −50 to +25° C. and forms a soft phase,

and the amount of the hard phase formed from the blocks S accounting for from 5 to 40% by volume, based on the total block copolymer; and

(D) 4 to 20 wt.-% of a graft rubber copolymer D obtained by mass polymerization and built up from:

(d 1 ) 10 to 25 wt.-% of at least one graft base (d 1 ) made from:

(d 11 ) 75 to 100 wt.-% of at least one diene, and

(d 12 ) 0 to 25 wt.-% of at least one vinylaromatic monomer, and

(d 2 ) 75 to 90 wt.-% of a graft (d 2 ), grafted onto the graft base and built up from:

(d 21 ) 68 to 82 wt.-% of at least one vinylaromatic monomer,

(d 22 ) 18 to 32 wt.-% of acrylonitrile or methacrylonitrile, and

(d 23 ) 0 to 20 wt.-% of one or more of the monomers as described for (a 23 );

wherein the sum of components A, B, C, and D totals 100 wt.-%.

2. The thermoplastic molding composition according to claim 1 , further comprising 0.01 to 20 parts by weight of at least one further additive and/or processing aid F, based on 100 parts by weight of the composition consisting of components A, B, C, and D.

3. The thermoplastic molding composition according to claim 1 , further comprising 0.01 to 10 parts by weight of at least one inorganic additive E selected from phyllosilicates (E1) and nano calcium carbonate (E2), based on 100 parts by weight of the composition consisting of components A, B, C, and D.

4. The thermoplastic molding composition according to claim 1 , comprising components A, B, C, and D in the following amounts:

(A): 15 to 28 wt.-%;

(B): 53 to 70 wt.-%;

(C): 6 to 15 wt.-%; and

(D): 6 to 15 wt.-%.

5. The thermoplastic molding composition according to claim 1 , comprising components A, B, C, and D in the following amounts:

(A): 18 to 25 wt.-%;

(B): 55 to 65 wt.-%;

(C): 6 to 15 wt.-%; and

(D): 6 to 15 wt.-%.

6. The thermoplastic molding composition according to claim 1 , wherein graft rubber copolymer A is built up from:

(a 1 ) 40 to 90 wt.-% of at least one graft base (a 1 ) made from:

(a 11 ) 80 to 98 wt.-% of at least one diene (a 11 ), and

(a 12 ) 2 to 20 wt.-% of at least one monomer (a 12 ); and

(a 2 ) 10 to 60 wt.-% of a graft (a 2 ), grafted onto the graft base (a 1 ) and built up from:

(a 21 ) 65 to 80 wt.-% of at least one vinylaromatic monomer (a 21 ),

(a 22 ) 20 to 35 wt.-% of acrylonitrile and/or methacrylonitrile (a 22 ), and

(a 23 ) 0 to 20 wt.-% of at least one monomer (a 23 ).

7. The thermoplastic molding composition according to claim 1 , wherein copolymer B is made from:

(b 1 ) 60 to 82 wt.-% of styrene or α-methylstyrene, and

(b 2 ) 18 to 40 wt.-% of acrylonitrile.

8. The thermoplastic molding composition according to claim 1 , wherein the elastomeric block B/S of block copolymer C is composed of about 75 to 30 wt.-% of vinylaromatic monomer, and 25 to 70 wt.-% of diene.

9. The thermoplastic molding composition according to claim 1 , wherein block copolymer C has one of the general formulae S-(B/S)-S, X-[-(B/S)-S] 2 , Y-[-(B/S)-S] 2 , Y[(B/S-S) n ] m [S] l , and Y[(S-B/S) n -S] m [S] l , where S is the vinylaromatic block and B/S is the soft phase, X is the radical of an n-functional initiator, Y is the radical of an m-functional or (m+l)-functional coupling agent, and l, m, and n are natural numbers from 1 to 10.

10. The thermoplastic molding composition according to claim 1 , wherein block copolymer C is a linear styrene-butadiene block copolymer of the general structure S-(S/B)-S having, situated between the two S blocks, one or more (S/B)-random blocks having random styrene/butadiene distribution, and a 1,2-vinyl content in the styrene-butadiene copolymer block (S/B) of below 20%.

11. The thermoplastic molding composition according to claim 1 , wherein graft copolymer D is built up from:

(d 1 ) 12 to 20 wt.-% of a graft base (d 1 ) made from:

(d 11 ) 75 to 100 wt.-% of 1,3-butadiene, and

(d 12 ) 0 to 25 wt.-% of styrene, and

(d 2 ) 80 to 88 wt.-% of a graft (d 2 ), grafted onto the graft base and built up from:

(d 21 ) 68 to 82 wt.-%, based on (d 2 ), of styrene, and

(d 22 ) 18 to 32 wt.-%, based on (d 2 ), of acrylonitrile.

12. The thermoplastic molding composition according to claim 3 , wherein component E1 is present in an amount of from 0.01 to 5 parts by weight.

13. The thermoplastic molding composition according to claim 3 , wherein component E2 is present in an amount of from 0.01 to 10 parts by weight.

14. A process for the preparation of the thermoplastic molding composition according to claim 1 in which the components A, B, C, and D are extrusion blended or compounded in conventional mixing apparatuses.

15. A process for the preparation of shaped articles comprising the thermoplastic molding composition according to claim 1 in which the shaped articles are formed by extrusion or co-extrusion.

16. Shaped articles comprising the thermoplastic molding composition according to claim 1 .

17. A method of use in which the thermoplastic molding composition of claim 1 is formed into articles requiring resistance to hydrofluoro olefins.

18. A method of use in which the thermoplastic molding composition of claim 2 is formed into articles requiring resistance to hydrofluoro olefins.

19. A method of use of the thermoplastic molding composition according to claim 1 for the preparation of inliners for cooling apparatuses.

20. A method of use of the thermoplastic molding composition according to claim 2 for the preparation of inliners for cooling apparatuses.