LED lighting elements comprising molded parts made of translucent polycarbonate compositions having a deep gloss effect

Abstract

The present invention relates to LED lighting elements comprising translucent mouldings composed of polycarbonate-based moulding compounds, comprising a colourant mixture, carbon black, scattering additive and optionally white pigment, as used, for example, as covers with a day/night design. Through combination with one or more RGB-LEDs, it is possible to achieve surprising colour effects in night design with presence of a deep gloss effect in mouldings that are black and grey in day design.

Claims

1. A LED lighting element comprising a moulding and one or more LEDs arranged in the LED lighting element such that they shine through the moulding, wherein the moulding has been produced from a translucent moulding compound consisting of a) 95% by weight to 99.95% by weight of aromatic polycarbonate, b) 0.0005% by weight of 0.02% by weight of a colourant mixture composed of colourants other than component c and component e, comprising at least two colourants selected from the group consisting of colourants based on anthraquinone, anthrapyridone, perinone, methine and quinoline, c) 0.00001% by weight to 0.02% by weight of carbon black, wherein the carbon black has a particle size of 10 to 30 nm; d) 0.05% to 0.6% by weight of at least one scattering additive selected from the group consisting of PMMA containing acrylate based scattering additives and silsesquioxane; e) 0.03% to 0.1% by weight of at least one white pigment, wherein the white pigment is titanium dioxide; f) optionally one or more further additives other than component b to component e., selected from the group consisting of demoulding agents, antioxidants, flame retardants, UV absorbers, IR absorbers, anti-dripping agents, optical brighteners, thermal stabilizers.

2. LED lighting element according to claim 1, wherein the colourants are selected from the group consisting of colourants based on anthraquinone, and anthrapyridone.

3. LED lighting element according to claim 1, wherein one colourant is a colourant based on anthraquinone and the other colourant is another colourant based on anthraquinone or a colourant based on anthrapyridone.

4. LED lighting element according to claim 1, wherein the moulding compound contains from 0.0002% to 0.015% by weight of carbon black.

5. LED lighting element according to claim 1, wherein the LED is an RGB-LED and/or the LEDs are RGB-LEDs.

6. LED lighting element according to claim 1, wherein the moulding has been printed on the side on which the LED(s) is/are disposed.

7. LED lighting element according to claim 1, wherein the moulding has a thickness of 0.5 mm to 4 mm.

8. A LED lighting element comprising a moulding and one or more LEDs arranged in the LED lighting element such that they shine through the moulding, wherein the moulding has been produced from a translucent moulding compound consisting of a) 95% by weight to 99.95% by weight of aromatic polycarbonate; b) 0.0005% by weight of 0.02% by weight of a colourant mixture composed of colourants other than component c and component e, comprising at least two colourants selected from the group consisting of colourants based on anthraquinone, anthrapyridone, perinone, methine and quinoline; c) 0.00001%0.002% by weight to 0.02% by weight of carbon black, wherein the carbon black has a particle size of 10 to 30 nm; d) 0.05% to 0.6% by weight of at least one scattering additive from the group consisting of PMMA containing acrylate-based scattering additives and silsesquioxane; f) optionally one or more further additives other than component b to e, selected from the group consisting of demoulding agents, antioxidants, flame retardants, UV absorbers, IR absorbers, anti-dripping agents, optical brighteners and/or thermal stabilizers, and wherein the moulding compound is free of white pigment.

Description

EXAMPLES

(1) Materials for Production of the Test Specimens a1: linear aromatic polycarbonate based on bisphenol A from Covestro Deutschland AG with an MVR of 19 cm.sup.3/(0 min) (determined according to ISO 1133-1:2012-03 at 300° C. with load 1.2 kg). b1: Macrolex® Blue RR, colourant of structure (15) from Lanxess Deutschland GmbH, C. I. (Color Index) 615290. b2: Macrolex® Red 5B, colourant of structure (11) from Lanxess Deutschland GmbH, C. I. 68210. b3: Macrolex® Violet 3R, colourant of structure (17) from Lanxess Deutschland GmbH, Solvent Violet 36. c: nanoscale carbon black (particle size about 17 nm), Black Pearls® 800 (CAS No. 1333-86-4) from Cabot Corp. d1: scattering additive, Ganzpearl SI-020, polymethylsilsesquioxane from Ganz Chemical Co., Ltd. d2: scattering additive, MBX-8 from Sekisui Plastics. Crosslinked polymethylmethacrylate of spherical geometry having an average particle diameter of 8 μm. e: Kronos 2230 titanium dioxide from Kronos Worldwide, Inc. f: thermal stabilizer.

(2) Production of the Test Specimens

(3) Compounding was effected on a KrausMaffei Berstorff ZE 25 twin-screw extruder at a barrel temperature of 260° C. or a melt temperature of 270° C. and at a speed of 100 rpm at a throughput of 10 kg/h with the amounts of components specified in the examples.

(4) The pellets were subsequently dried under reduced pressure at 120° C. for 3 hours and then injection-moulded using an Arburg 370 injection-moulding machine at a melt temperature of 300° C. and a mould temperature of 90° C. to give specimen plaques of dimensions 50 mm×75 mm in different thicknesses (1 to 4 mm).

(5) TABLE-US-00001 TABLE 1 Compositions Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 (inventive) (inventive) (inventive) (inventive) (inventive) (inventive) a1 % by wt. 99.93455 99.36891 99.32891 99.61885 99.80345 98.919883 b1 % by wt. 0.0024 0.0004 0.0004 0.013 0.007 0.000057 b2 % by wt. 0.00075 0.00415 0.00225 b3 % by wt. 0.00024 0.00024 0.000060 c % by wt. 0.0023 0.00045 0.00045 0.014 0.0073 d1 % by wt. 0.060 0.49 0.49 0.35 0.18 d2 % by wt. 0.98 e % by wt. 0.04 0.08 f % by wt. 0.1 0.1 0.1

(6) The specimen plaques in different thickness were illuminated with RGB-LED light from the reverse side to produce a night design. Whereas there was a dark deep gloss effect in the day design, the light and its colour were clearly apparent on illumination by means of LED light from the reverse side. Specimen plaques which, as well as the injection-moulded moulding compound, also had a printed colour layer of a colour that was not transparent (significantly transparent) the respective LED light in partial regions on the reverse side lit up only in the unprinted partial regions as a result of the LED lighting incident from the rear.