BLACK-COLORED POLYAMIDE COMPOSITION AND PRODUCTION AND USE THEREOF

Abstract

The present invention relates to a polyamide composition which is dyed in black, comprising a chromium-containing azo dye in the form of a 1:2 chromium complex, to the production of such a polyamide composition and to the use thereof for the preparation of polyamide molded bodies and fibers, which are dyed in black. The invention further relates to a method for laser welding using at least one molding part on the basis of such a polyamide composition.

Claims

1. A polyamide composition comprising a) at least one synthetic polyamide and b) at least one chromium complex dye selected from the group consisting of a compound of formula (A1), a compound of formula (A2), and a compound of formula (A3): ##STR00007##

2. The polyamide composition according to claim 1, wherein the at least one synthetic polyamide is selected from the group consisting of PA 4, PA 5, PA 6, PA 7, PA 8, PA 9, PA 10, PA 11, PA 12, PA 46, PA 66, PA 666, PA 69, PA 610, PA 612, PA 96, PA 99, PA 910, PA 912, PA 1212, PA 6.T, PA 9.T, PA_8.T, PA 10.T, PA 12.T, PA 6.I, PA 8.I, PA 9.I, PA 10.I, PA 12.I, PA 6.T/6, PA 6.T/10, PA 6.T/12, PA 6.T/6.I, PA6.T/8.T, PA 6.T/9.T, PA 6.T/10T, PA 6.T/12.T, PA 12.T/6.T, PA 6.T/6.I/6, PA 6.T/6.I/12, PA 6.T/6.I/6.10, PA 6.T/6.I/6.12, PA 6.T/6.6, PA 6.T/6.10, PA 6.T/6.12, PA 10.T/6, PA 10.T/11, PA 10.T/12, PA 8.T/6.T, PA 8.T/66, PA 8.T/8.I, PA 8.T/8.6, PA 8.T/6.I, PA 10.T/6.T, PA 10.T/6.6, PA 10.T/10.I, PA 10T/10.I/6.T, PA 10.T/6.I, PA 4.T/4.I/46, PA 4.T/4.I/6.6, PA 5.T/5.I, PA 5.T/5.I/5.6, PA 5.T/5.I/6.6, PA 6.T/6.I/6.6, PA MXDA.6, PA IPDA.I, PA IPDA.T, PA MACM.I, PA MACM.T, PA PACM.I, PA PACM.T, PA MXDA.I, PA MXDA.T, PA 6.T/IPDA.T, PA 6.T/MACM.T, PA 6.T/PACM.T, PA 6.T/MXDA.T, PA 6.T/6.I/8.T/8.I, PA 6.T/6.I/10.T/10.I, PA 6.T/6.I/IPDA.T/IPDA.I, PA 6.T/6.I/MXDA.T/MXDA.I, PA 6.T/6.I/MACM.T/MACM.I, PA 6.T/6.I/PACM.T/PACM.I, PA 6.T/10.T/IPDA.T, PA 6.T/12.T/IPDA.T, PA 6.T/10.T/PACM.T, PA 6.T/12.T/PACM.T, PA 10.T/IPDA.T, PA 12.T/IPDA.T, and copolymers thereof.

3. The polyamide composition according to claim 1 wherein the at least one chromium complex dye b) is present in an amount of 0.0001% by weight to 5% by weight, based on a total weight of the polyamide composition.

4. The polyamide composition according to claim 1, wherein the composition further comprises at least one of the following c)-f): c) at least one thermoplastic polymer other than component a), d) at least one colorant other than component b), e) at least one filler and reinforcer, f) at least one additive other than components a) to e).

5. The polyamide composition according to claim 4, comprising a) 5% by weight to 99.9999% by weight of the at least one synthetic polyamide, b) 0.0001% by weight to 5% by weight of the at least one chromium complex dye selected from the group consisting of a compound of formula (A1), a compound of formula (A2), and a compound of formula (A3), c) 0% by weight to 94.9999% by weight of at the least one thermoplastic polymer other than component a), d) 0% by weight to 10% by weight of the at least one colorant other than component b), and f) 0% by weight to 50% by weight of the at least one additive other than components a) to d), with the proviso that components a), b), c), d) and f) add up to 100% by weight.

6. The polyamide composition according claim 4, wherein component c) is present and is selected from homo- or copolymers which comprise, in polymerized form, at least one monomer selected from the group consisting of C.sub.2-C.sub.10 monoolefins, 1,3-butadiene, 2-chloro-1,3-butadiene, vinyl alcohol, C.sub.2-C.sub.10-alkyl esters of vinyl alcohol, vinyl chloride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, glycidyl acrylate, glycidyl methacrylate, acrylates with alcohol components of branched C.sub.1-C.sub.10-alcohols, acrylates with alcohol components of unbranched C.sub.1-C.sub.10-alcohols, methacrylates with alcohol components of branched C.sub.1-C.sub.10-alcohols, methacrylates with alcohol components of unbranched C.sub.1-C.sub.10-alcohols vinylaromatics, acrylonitrile, methacrylonitrile, ,-ethylenically unsaturated monocarboxylic acids, ,-ethylenically unsaturated dicarboxylic acids, and maleic anhydride; homo- and copolymers of vinyl acetals; polyvinyl esters; polycarbonates (PC); polyesters; polyethers; polyether ketones; thermoplastic polyurethanes (TPU); polysulfides; polysulfones; polyether sulfones; cellulose alkyl esters; and mixtures thereof.

7. The polyamide composition according to claim 4, wherein component c) is present and is selected from the group consisting of styrene copolymers, polyalkyl(meth)acrylates, polycarbonates, and mixtures thereof.

8. The polyamide composition according to claim 4, wherein component d) is present and comprises at least one non-nucleating colorant other than component b).

9. The polyamide composition according to claim 4, wherein component d) is present and comprises at least one white pigment.

10. The polyamide composition according to claim 4, having, in the CIELAB color space according to DIN 6174 with the specular component included, an L* value of not more than 30, having, in the CIELAB color space according to DIN 6174 with the specular component excluded, an L* value of not more than 20, or having, in the CIELAB color space according to DIN 6174 with the specular component included, an L* value of not more than 30 and with the specular component excluded, an L* value of not more than 20.

11. The polyamide composition according to claim 1, wherein the composition is.

12. A method for producing black molding for use in motor vehicles, domestic appliances, electrical appliances, decorative strips, and exterior paneling, the method comprising processing the polyamide composition as defined in claim 11.

13. A shaped body or a polyamide fiber comprising the polyamide composition according to claim 1.

14. A process for producing the polyamide composition of claims of claim 1, in which the at least one synthetic polyamide a), the at least one chromium complex dye b), and optionally further additives, are mixed with one another while heating to a temperature in a range from 160 C. to 340 C.

15. A molding for laser transmission welding, the molding comprising the polyamide composition of claim 1.

Description

DESCRIPTION OF FIGURES

[0237] FIG. 1 shows the diffuse transmission of the chromium complex dye of the invention and nigrosin base (=Solvent Black 7) as a function of wavelength. The measurement was effected on polyamide test specimens made from PA6 (Ultramid B3S from BASF SE) having a thickness of 2 mm and a dye content of 0.05% by weight by means of an Agilent Technologies Cary 5000 spectrophotometer.

[0238] The examples which follow serve to illustrate the invention, but without restricting it in any way.

EXAMPLES

Example 1

[0239] 99.95 parts polyamide PA6 (Ultramid B3S from BASF) were premixed in a tumbling mixer with 0.05 part Solvent Black 28 (Orasol Black 045 from BASF) for 10 minutes and then extruded and pelletized using a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 260 C. For this purpose, the natural-colored polyamide pellets were dried beforehand in a drying oven at 100 C. for 4 hours, such that the moisture content was below 0.1%. For this purpose, the moisture content was determined by means of a thermal balance. The homogeneous pellets obtained were injection-molded on an injection molding machine at melt temperature 260 C., 280 C. and 300 C. to give plaques of thickness 2 mm and of dimensions 4560 mm, and were assessed both visually and analytically.

[0240] Colorimetry in accordance with DIN 6174 and evaluation in accordance with DIN EN 12877-2 showed a dE at 280 C. of 2.1 and a dE at 300 C. of 4.8. A visual determination of the color difference at 300 C., by means of a gray scale in accordance with DIN EN 20105-A02 Tests for colour fastness, gave a grade of 4-5 and hence only a small color change was found.

[0241] The migration of the black dye out of the polyamide was tested by means of standard EN 14469-4 Pigments and extendersTesting of colouring materials in plasticized polyvinyl chloride (PVC-P) Part 4: Determination of bleeding of colouring materials. The grade of 5 obtained showed non-migratory behavior of the Solvent Black 28 dye.

[0242] The transparency of the black 2 mm-thick plaques obtained in the near-infrared (NIR) was measured by means of the Agilent Technologies Cary 5000 UV-VIS-IR spectrometer (with DRA 2500 Diffuse Reflectance Accessory) within the wavelength range of 300 nm to 2500 nm. A transmission of more than 50% was found within the wavelength range from 800 to 900 nm which is of technical interest, and a transmission of more than 60% in the wavelength range from 900 to 1100 nm.

[0243] Determination of the crystallization temperature of the colored polyamide in the cooling phase by means of differential scanning calorimetry (DSC) in accordance with DIN EN ISO 11357 gave a temperature of 222.2 C., whereas a temperature of 222.5 C. was measured in example 5. It was thus possible to demonstrate surprisingly good thermal stability, very good migration resistance and very good transmission in the near infrared region.

Example 2

[0244] 99.4 parts polyamide PA6 (Ultramid B3S from BASF) were premixed in a tumbling mixer with 0.1 part Solvent Black 28 (Orasol Black 045 from BASF) and 0.5 part titanium dioxide (Kronos 2220 from Kronos) for 10 minutes and then extruded and pelletized using a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 260 C. For this purpose, the natural-colored polyamide pellets were dried beforehand in a drying oven at 100 C. for 4 hours, such that the moisture content was below 0.1%. For this purpose, the moisture content was determined by means of a thermal balance. The homogeneous pellets obtained were injection-molded on an injection molding machine at melt temperature 260 C., 280 C. and 300 C. to give plaques of thickness 2 mm and of dimensions 4560 mm, and were assessed both visually and analytically.

[0245] Colorimetry in accordance with DIN 6174 and evaluation in accordance with DIN EN 12877-2 showed a dE at 280 C. of 2.0 and a dE at 300 C. of 5.0. A visual determination of the color difference at 300 C., by means of a gray scale in accordance with DIN EN 20105-A02 Tests for colour fastness, gave a grade of 4-5 and hence only a small color change was found.

[0246] The migration of the black dye out of the polyamide was tested by means of standard EN 14469-4 Pigments and extendersTesting of colouring materials in plasticized polyvinyl chloride (PVC-P) Part 4: Determination of bleeding of colouring materials. The grade of 5 obtained showed non-migratory behavior of the Solvent Black 28 dye.

[0247] It was thus possible to demonstrate surprisingly good thermal stability, very good migration resistance and comparable crystallization behavior of the PA to example 5.

Example 3 (Comparative)

[0248] 98 parts polyethylene (Grade M80064 from Sabic) were premixed in a tumbling mixer with 2 parts Solvent Black 28 (Orasol Black 045 from BASF) for 10 minutes and extruded in a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 210 C. A significant odor developed from the extruder nozzle; the polymer strands had expanded in the foam mold. The production of plaques by means of injection molding machines was not possible.

[0249] Incorporation and black coloring of the polyethylene by means of Solvent Black 28 was thus not possible.

Example 4 (Comparative)

[0250] 99.9 parts polyamide PA6 (Ultramid B3S from BASF) were premixed in a tumbling mixer with 0.1 part Solvent Violet 13 (Orasol Blue 640 from BASF) for 10 minutes and then extruded and pelletized using a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 260 C. For this purpose, the natural-colored polyamide pellets were dried beforehand in a drying oven at 100 C. for 4 hours, such that the moisture content was below 0.1%. For this purpose, the moisture content was determined by means of a thermal balance. The homogeneous pellets obtained did not show the expected pure blue color, but a dirty gray hue. It was clearly apparent that the dye did not have any coloring effect.

Example 5 (Comparative)

[0251] 99.95 parts polyamide PA6 (Ultramid B3S from BASF) were premixed in a tumbling mixer with 0.05 part of the Solvent Black 7 dye (Nubian black TN-870 from Orient Chemicals) for 10 minutes and then extruded and pelletized using a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 260 C. For this purpose, the natural-colored polyamide pellets were dried beforehand in a drying oven at 100 C. for 4 hours, such that the moisture content was below 0.1%. For this purpose, the moisture content was determined by means of a thermal balance. The homogeneous pellets obtained were injection-molded on an injection molding machine at melt temperature 260 C., 280 C. and 300 C. to give plaques of thickness 2 mm and of dimensions 4560 mm.

[0252] The transparency of the black 2 mm-thick plaques obtained in the near-infrared (NIR) was measured by means of a UV-VIS-IR spectrometer (see above) within the wavelength range of 300 nm to 2500 nm. A transmission of below 15% was found within the wavelength range from 800 to 900 nm which is of technical interest, and a transmission of well below 40% in the wavelength range from 900 to 1100 nm.

[0253] It was thus possible to demonstrate much poorer transmission in the near infrared region (NIR) compared to Solvent Black 28.

Example 6

[0254] 99.95 parts glass-modified polyamide PA6 (Ultramid B3EG7 from BASF) were premixed in a tumbling mixer with 0.05 part Solvent Black 28 (Orasol Black 045 from BASF) for 10 minutes and then extruded and pelletized using a twin-shaft extruder having a diameter of 18 mm and an L/D ratio of 44 at barrel temperature 280 C. For this purpose, the natural-colored polyamide pellets were dried beforehand in a drying oven at 100 C. for 4 hours, such that the moisture content was below 0.1%. The homogeneous pellets obtained were injection-molded on an injection molding machine at melt temperature 260 C., 280 C. and 300 C. to give plaques of thickness 2 mm and of dimensions 4560 mm, and were assessed both visually and analytically.

[0255] Colorimetry in accordance with DIN 6174 and evaluation in accordance with DIN EN 12877-2 showed a dE at 280 C. of 1.2 and a dE at 300 C. of 6.1. A visual determination of the color difference at 300 C., by means of a gray scale in accordance with DIN EN 20105-A02 Tests for colour fastness, gave a grade of 4-5 and hence only a small color change was found. It was thus possible to demonstrate surprisingly good thermal stability.