Impact-modified polycarbonate compositions for simplified production of components of low temperature toughness having high gloss and matt component sections
View Patent ↗The present invention relates to impact-modified polycarbonate molding compositions, the use thereof for producing shaped bodies and moldings, as well as shaped bodies and molding produced therefrom themselves. Compositions of the present invention comprise mixtures of graft polymers prepared in the emulsion polymerization process and in the bulk, solution and/or suspension polymerization process having a defined grafted particle size distribution. Compositions of the present invention, on the one hand are suitable for producing, over a wide processing window, (i.e. also at high processing temperatures), non-lacquered components having a high gloss surface, and on the other hand, are also capable of precise imaging of fine-grained or surface-etched mold surfaces. A result of this point is that components of the present invention are capable of having both high gloss and deep matte component sections that can be realized in a mold having different surface textures in a single injection molding step without further after-treatment of the surface. The molding compositions have a high heat distortion temperature and ductility at low temperatures and an excellent resistance to stress cracking under the influence of media—which is particularly important with respect to non-lacquered components.
1. A polymer composition comprising:
A) from 45 to 95 parts by wt., based on the sum of A and B, wherein the parts by weight of A and B add up to 100, of aromatic polycarbonate and/or polyester carbonate,
B) from 5 to 55 parts by wt., based on the sum of A and B, of a mixture comprising:
B1) at least one graft polymer prepared by an emulsion polymerization process,
B2) at least one graft polymer prepared by a bulk, suspension and/or solution polymerization process,
B3) optionally a rubber-free vinyl (co)polymer,
wherein said graft polymers B1 and B2 are both based on butadiene-containing elastomeric graft bases B1.2 and B2.2 and in which the total content of butadiene from the graft bases B1.2 and B2.2, based on the total composition, is from 5 to 12 wt. %, and
C) from 0 to 30 parts by wt., based on the sum of A and B, of at least one commercially available polymer additive,
wherein
(i) the composition comprises not more than 2.0 wt. % of grafted particles from components B1 and B2 having an associated grafted particle diameter of at least 800 nm, and comprises not more than 2.0 wt. % of grafted particles from components B1 and B2 having an associated grafted particle diameter of at most 100 nm, and
(ii) the graft polymer according to component B1 is prepared by grafting a mixture (B1.1) of vinylic compounds on to a particulate rubber-elastic graft base (B1.2), wherein said grafting is started using an inorganic persulfate compound as a polymerization initiator, and
(iii) the composition is free from graft polymers prepared by an emulsion polymerization process which have been prepared using a redox-based polymerization initiator system.
2. The composition according to claim 1 , wherein:
(i) the composition comprises not more than 1.5 wt. % of grafted particles from components B1 and B2 having an associated grafted particle diameter of at least 800 nm, and comprises not more than 1.5 wt. % of grafted particles from components B1 and B2 having an associated grafted particle diameter of at most 100 nm.
3. The composition according to claim 1 , comprising from 55 to 75 parts by wt., based on the sum of A and B, of aromatic polycarbonate and/or polyester carbonate.
4. The composition according to claim 1 , comprising:
A) from 55 to 75 parts by wt., based on the sum of A and B, of aromatic polycarbonate and/or polyester carbonate,
B) from 25 to 45 parts by wt., based on the sum of A and B, of a mixture comprising:
B1) at least one graft polymer prepared by an emulsion polymerization process,
B2) at least one graft polymer prepared in a bulk, suspension and/or solution polymerization process,
B3) optionally a rubber-free vinyl (co)polymer, and
C) from 0.3 to 7 parts by wt., based on the sum of A and B, of at least one polymer additive.
5. The composition according to claim 1 , wherein the aromatic polycarbonate and/or polyester carbonate according to component A has a weight-average molecular weight M w , measured by GPC in methylene chloride at 25° C. using a polycarbonate standard, of from 26,000 to 31,000 g/mol.
6. The composition according to claim 1 , wherein said graft polymer B2 is present in a content of from 10 to 45 parts by wt., based on the sum of B1 and B2.
7. The composition according to claim 1 , wherein said component B1 is a graft polymer, prepared by an emulsion polymerization process, of B1.1) from 20 to 60 wt. %, based on component B1, of a mixture of B1.1.1) from 70 to 80 wt. %, based on B1.1, of at least one monomer selected from the group consisting of vinylaromatics, vinylaromatics substituted on the nucleus, and (meth)acrylic acid (C1-C8)-alkyl esters; and B1.1.2) from 20 to 30 wt. %, based on B1.1, of at least one monomer selected from the group consisting of vinyl cyanides, (meth)acrylic acid (C1-C8)-alkyl esters, and derivatives of unsaturated carboxylic acids, on B1.2) from 80 to 40 wt. %, based on component B1, of at least one elastomeric graft base having a glass transition temperature of <−60° C., and wherein said component B2 is a graft polymer, prepared by a bulk, solution and/or suspension polymerization process, of B2.1) from 87 to 93 wt. %, based on component B2, of a mixture of B2.1.1) from 70 to 80 wt. %, based on said mixture B.2.1, of at least one monomer selected from the group of vinylaromatics, vinylaromatics substituted on the nucleus and (meth)acrylic acid (C1-C8)-alkyl esters, and B2.1.2) from 20 to 30 wt. %, based on said mixture B2.1, of at least one monomer selected from the group consisting of vinyl cyanides, (meth)acrylic acid (C1-C8)-alkyl esters, and derivatives of unsaturated carboxylic acids, on B2.2) from 13 to 7 wt. %, based on said componenet B2, of at least one graft base comprising a glass transition temperature of <−60° C.
8. The composition according to claim 1 , wherein the grafted particles in said graft polymer B1 prepared by an emulsion polymerization process have an average particle size (D50 value) of from 0.2 to 0.5 um.
9. The composition according to claim 1 , wherein the grafted particles in said graft polymer B2 prepared by a bulk, solution and/or suspension polymerization process have an average particle size (D50 value) of from 0.3 to 0.6 um.
10. The composition according to claim 1 , wherein said graft polymer B2 prepared by a bulk, solution and/or suspension polymerization process is based on a styrene/butadiene block copolymer rubber and/or a mixture of styrene/butadiene block copolymer rubber with pure polybutadiene rubber as the graft base B2.2, has a gel content of from 17 to 23 wt. %, measured in acetone, and comprises free copolymer from B2.1.1 and B2.1.2 having a weight-average molecular weight Mw, determined in tetrahydrofuran by gel permeation chromatography with polystyrene as the standard, of from 80,000 to 120,000 g/mol.
11. The composition according to claim 1 , wherein component (c) is present and comprises at least one polymer additive selected from the group consisting of flameproofing agents, flameproofing synergists, smoke-suppressing additives, antidripping agents, internal and external lubricants and mould release agents, flowability auxiliary agents, antistatics, conductivity additives, UV/light stabilizers, heat stabilizers, antioxidants, transesterification inhibitors, agents which prevent hydrolysis, antibacterially acting additives, additives which improve scratch resistance, IR absorbents, optical brighteners, fluorescent additives, fillers and reinforcing substances, acids and dyestuffs and pigments.
12. The composition according to claim 1 , wherein component (c) is present and comprises at least one phosphorus-containing flameproofing agent selected from the group consisting of mono- and oligomeric phosphoric and phosphonic acid esters, phosphonatamines and phosphazenes.
13. A shaped body and/or moulding comprising a composition according to claim 1 , which is produced in a single production step in an injection moulding process without a further surface after-treatment step, and which comprises one or more high gloss component sections having a gloss, determined in reflection in accordance with DIN 67530 at a measuring angle of 60°, of at least 98 and one or more deep matte component sections having a gloss, determined in reflection in accordance with DIN 67530 at a measuring angle of 60°, of at most 2.
14. The shaped body and/or moulding according to claim 13 , which have been produced in a single production step in an injection moulding process without a further surface after-treatment step and which have one or more high gloss component sections having a gloss, determined in reflection in accordance with DIN 67530 at a measuring angle of 60°, of at least 99, and one or more deep matte component sections having a gloss, determined in reflection in accordance with DIN 67530 at a measuring angle of 60°, of at most 1.2.
15. The composition according to claim 1 , wherein component C) is present.
16. The composition according to claim 1 , wherein B1) comprises an ABS graft polymer and B2 comprises an ABS graft polymer.