Deep black thermoplastic molding compositions having high gloss and production thereof
Deep black thermoplastic molding compositions having high gloss can be produced by mixing the following components: 90% to 99.5% by weight of one or more styrene copolymers as component A1, or 90% to 99.5% by weight of one or more polymethylmethacrylates (PMMA) and/or polyalkylmethacrylates as component A2, or 90% to 99.5% by weight of one or more polycarbonates (PC) and/or polyester carbonates as component A3, 0.01% to 5% by weight of a pigment black as component B, 0.1% to 1.5% by weight of at least two dyes soluble in the molding composition as component C, 0% to 5% by weight of one or more additives other than components B and C, as component D. These are found to be particularly weathering-resistant.
1. A black thermoplastic molding composition with high gloss, consisting of:
A) from 90 to 99.5% by weight of one or more styrene copolymers as component A1,
B) from 0.01 to 5% by weight of a carbon black pigment as component B,
C) as component C, from 0.5 to 1.2% by weight of at least three dyes soluble in the molding composition,
D) as component D, from 0 to 5% by weight of one or more additional substances different from components B and C,
where component A is a copolymer selected from the group consisting of acrylonitrile, styrene, and/or α-methylstyrene, phenylmaleimide, maleic anhydride, methyl methacrylate, and a mixture of these,
where the ratio by weight of component B used to component C used is from 3:1 to 1:15,
where the at least three dyes cover complementary color regions such that the combination produces a black color,
where the thermoplastic molding compositions have a deep-black color with L*-values from 0.5 to 2.0, measured in accordance with DIN 5033:2009, and a high gloss of more than 98, measured in accordance with DIN 67530:1982, and
where each of the percentages by weight is based on the total weight of components A to D, and these give a total of 100 percent by weight.
2. The thermoplastic molding composition as claimed in claim 1 , characterized in that the molding composition consists of, as component B, from 0.01 to 5% by weight of a carbon black pigment which has an average primary particle size in the range from 5 to 100 nm.
3. The thermoplastic molding composition as claimed in claim 1 , characterized in that component A is a copolymer of acrylonitrile, styrene, and/or α-methylstyrene, and the proportion by weight of acrylonitrile, based on component A, is from 19 to 39% by weight.
4. The thermoplastic molding composition as claimed in claim 1 , characterized in that component A is a styrene/acrylonitrile copolymer or an α-methylstyrene/acrylonitrile copolymer.
5. The thermoplastic molding composition as claimed in claim 1 , characterized in that component A is a transparent styrene/acrylonitrile copolymer or a transparent α-methylstyrene/acrylonitrile copolymer with a melt volume rate, MVR, 220/3.8, of from 4 to 22 cm 3 /10 min.
6. The thermoplastic molding composition as claimed in claim 1 , characterized in that component A is a styrene/methyl methacrylate copolymer, where the proportion by weight of MMA, based on component A, is from 19 to 31% by weight.
7. The thermoplastic molding composition as claimed in claim 1 , characterized in that the proportion by weight of B is from 0.05 to 3% by weight.
8. A method of producing a molded object with a deep-black surface and high gloss comprising the step of molding the thermoplastic molding compositions as claimed in claim 1 wherein the molded object is an object for use in a motor vehicle, a household appliance, electrical equipment, a decorative strips, or outdoor cladding.
9. A method as claimed in claim 8 wherein the molded object is an object for use in the exterior region of a motor vehicle selected from A-, B-, C-, or D-pillar cladding, a spoiler, a window frame, a cover strip, a hood, a panel, a part of a radiator grille, antenna cladding, of the side mirror, or a part of a front or rear lamp.
10. A process as claimed in claim 1 , characterized in that components A, B, and C, and also optionally D, are mixed with one another.
11. The thermoplastic molding composition as claimed in claim 2 , characterized in that the molding composition consists of, as component B, from 0.01 to 5% by weight of a carbon black pigment which has an average primary particle size in the range from 7 to 60 nm.