POLYAMIDE COMPOSITION WHICH IS DYED IN BLACK, PRODUCTION AND USE THEREOF

Abstract

Disclosed herein is a black-colored polyamide composition which includes a polycondensate of formaldehyde, n-phenyl-benzene amine and 2-propanone and carbon black, and preferably also glass fibers, production of this polyamide composition and use thereof for the production of black-colored laser-inscribable polyamide moldings.

Claims

1. A polyamide composition comprising a) from 34.89 to 99.89% by weight of at least one synthetic polyamide as component A and b) from 0.1 to 5% by weight of a polycondensate of formaldehyde, n-phenyl-benzene amine and 2-propanone as component B, c) from 0.01 to 1% by weight of carbon black as component C, d) from 0 to 65% by weight of glass fibers as component D, and e) from 0 to 50% by weight of other additional substances as component E, wherein the quantities stated, which give a total of 100% by weight, are based on the entire composition.

2. The polyamide composition according to claim 1, wherein the composition comprises 10 to 65% by weight of glass fibers and 34.89 to 89.89% by weight of component A.

3. The polyamide composition according to claim 1, wherein the composition comprises, alongside components B and C, no other black-coloring dyes or pigments.

4. The polyamide composition according to claim 1, wherein the quantity of components C is from 0.2 to 2.5% by weight

5. The polyamide composition according to claim 1, wherein lubricants and heat stabilizers are used as component E in quantities of respectively from 0.05 to 1.0% by weight, based on the entire composition. The polyamide composition according to claim 1, where the 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 8.1, PA 9.1, PA 10.I, PA 12.1, PA 6.T/6, PA 6.T/10, PA 6.T/12, PA 6.T/6.I, PA 6.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/6.116.10, PA 6.T/6.116.12, 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/10.116.T, PA 10.T/6.I, PA 4.T/4.1146, PA 4.T/4.116.6, PA 5.T/5.I, PA 5.T/5.115.6, PA 5.T/5.I/6.6, PA 6.T/6.116.6, 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/6.1/10.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 and mixtures thereof.

7. The polyamide composition according to claim 1, where component E comprises at least one polymer selected from the group consisting of homo- or copolymers which comprise, in copolymerized form, at least one monomer selected from the group consisting of C.sub.2-C.sub.10 monoolefins, ethylene, propylene, 1,3-butadiene, 2-chloro-1,3-butadiene, vinyl alcohol and its C.sub.2-C.sub.10-alkyl esters, vinyl chloride, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, glycidyl acrylate, glycidyl methacrylate, acrylates and methacrylates having alcohol components of branched and unbranched C.sub.1-C.sub.10-alcohols, vinyl aromatics, styrene, acrylonitrile, methacrylonitrile, α,β-ethylenically unsaturated mono- and dicarboxylic acids, and maleic anhydride; homo- and copolymers of vinyl acetals; polyvinyl esters; polycarbonates (PC); polyesters, polyalkylene terephthalates, polyhydroxyalkanoates (PHA), polybutylene succinates (PBS), polybutylene succinate adipates (PBSA); polyethers; polyetherketones; thermoplastic polyurethanes (TPU); polysulfides; polysulfones; polyether sulfones; cellulose alkyl esters; and mixtures thereof.

8. A method of using the polyamide composition of claim 1, the method comprising using the polyamide composition for the production of black-colored laser-inscribable polyamide moldings with high surface smoothness.

9. The method of use according to claim 8, the method comprising using the polyamide composition for the production of moldings for use in motor vehicles, in household equipment, in electrical devices, or in decorative strips and external cladding.

10. A molding produced from a polyamide molding composition according to claim 1.

11. A process for the production of the polyamide composition of claim 1, wherein at least one synthetic polyamide A, at least one polycondensate B, carbon black C, and optionally other additives are mixed with one another with heating to a temperature in the range from 160 to 340° C.

12. The polyamide composition according to claim 1, wherein the composition comprises, alongside components B and C, no other dyes or coloring pigments.

13. The polyamide composition according to claim 1, wherein the quantity of components C is from 0.3 to 1.5% by weight.

14. The polyamide composition according to claim 1, where the polyamide is selected from the group consisting of PA 6, PA 66, PA 666 and PA 12.

15. The polyamide composition according to claim 1, where the polyamide is PA 66 or PA 6.

16. The polyamide composition according to claim 1, where component E comprises at least one polymer selected from the group consisting of styrene copolymers, polyalkyl (meth)acrylates, polycarbonates and mixtures thereof.

Description

EXAMPLES

[0174] The Following Raw Materials were Used:

[0175] PA 66:

[0176] Polyamide 66 having a VZ of 150 ml/g, measured as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid®A27 manufactured by BASF SE has been used).

[0177] PA 6:

[0178] Polyamide 6 having a VZ of 150 ml/g, measured as 0.5 wt % solution in 96 wt % sulfuric acid at 25° C. according to ISO 307 (Ultramid® B27 manufactured by BASF SE has been used).

[0179] Glass Fiber:

[0180] DS 1110 having an average fiber diameter of 10 μm manufactured by 3B Fibreglass.

[0181] Polymeric Additive:

[0182] Copolymer consisting of formaldehyde, n-phenylbenzenamine and 2-propanon as monomeric units (CAS: 9003-80-9) manufactured by SI Group.

[0183] Carbon Black:

[0184] Special Black 4 manufactured by Orion Engineered Carbons GmbH.

[0185] Nigrosine Masterbatch:

[0186] Nigrosine Masterbatch consisting of 40 wt % nigrosine (Solvent Black 7, CAS: 8005-02-5) in polyamide 6.

[0187] Lubricant:

[0188] Ethylene-bis-stearylamide manufactured by Lonza Cologne GmbH.

[0189] Fabrication of Compounds:

[0190] Reference is made to the German standard DIN and ISO norms and other norms valid in 2019.

[0191] The natural-colored polyamide granulates were previously dried in a drying oven at 100° C. for four hours so that the moisture content of below 0.1% while all other ingredients were premixed in a tumble mixer for 10 minutes. In the next step the dried polyamide granulates together with the dry blended ingredients were melt extruded and granulated using a twin-screw extruder with a diameter of 25 mm and an L/D (length/diameter) ratio of 44 at 300° C. cylinder temperature. The resulting granules were injection molded on an injection molding machine at 300° C. melt temperature to various specimen for the adjacent characterization. The mechanical properties were determined in accordance with the DIN ISO 527 and 179-2/1 eU or 179-2/1 eAf.

[0192] Melting and crystallization point of the compounds were measured according to DIN 11357 using differential scanning calorimeter (DSC) at a scan speed of 5 K/min.

[0193] The measurement of the surface roughness (arithmetic mean roughness Ra, square roughness Rq and average surface roughness Rz) was determined using a NT9300 white light interferometer by Veeco. The laser contrast values were measured in accordance with DIN 66236. The laser marking can be done for example with a laser FOBA DP50, which is a diode-pumped Nd:YAG laser having a wavelength of 1064 nm. The typical laser power is 50 W. The luminance value can be determined for example with a Minolta Luminance Meter LS-110. It is a SLR spot luminance meter for measuring light source and surface brightness. The measuring angle is ⅓° of viewing angle 9°. As an optical system an 85 mm f/2.8 lens with a SLR viewing system is used. The scattered light factor is less than 1.5%.

[0194] The contrast value according to DIN 66236 describes the difference in intensity between the brightest and darkest point divided by the intensity of the brightest point of the substrate.

[0195] The composition of the molding compositions according to the examples and comparative examples are shown in the following Table 1. Furthermore, the mechanical properties, surface roughness and laser inscribability results are also given in the table.

TABLE-US-00001 TABLE 1 Comparative Comparative Comparative Comparative Composition DIN ISO Example 1 Example 2 Example 1 Example 3 Example 4 Example 2 PA 66 69.7 69.7 68.7 0 0 0 PA 6 0 0 0 69.7 69.7 68.7 Glass fiber 30 30 30 30 30 30 Polymeric Additive 0 0 1 0 0 1 Nigrosine Masterbatch 0 0.5 0 0 0.5 0 Carbon Black 0.1 0.1 0.1 0.1 0.1 0.1 Lubricant 0.2 0.2 0.2 0.2 0.2 0.2 Melting point (DSC) 11357 261 260 260 220 220 220 [° C.] Crystallization point 11357 230 223 226 191 182 188 (DSC) [° C.] Mechanical Properties (dry as moulded) Tensile modulus [MPa] 527 9700 9600 9730 9300 9300 9400 Tensile strength [MPa] 527 178 177 182 175 172 175 Elongation at break [%] 527 3.7 3.9 3.9 3.5 3.5 3.5 Charpy unnotched impact 179-2/1eU 74 83 90 102 105 98 strength Charpy notched impact 179-2/1eAf 8.3 8.4 8.6 11.0 14.5 12.8 strength [kJ/m.sup.2] Surface Roughness Arithmetical mean 323 253 276 177 185 153 height (Ra) [μm] Root mean squared 605 484 488 277 280 209 (Rq) [μm] Mean peak to valley 42 38 36 9 9 7 height (Rz) [μm] Laser markability Laser contrast 66236 94.9 (excellent 91.5 (medium 95.3 (excellent 94.7 (excellent 91.2 (medium 95.9 (excellent contrast) contrast) contrast) contrast) contrast) contrast) Luminance (max. 66236 257 106 260 258 109 261 brightness in cd/m.sup.2)

[0196] As it is evident from Comparative Examples 1 and 2 and likewise Comparative Examples 3 and 4, the addition of nigrosine to a molding composition containing carbon black leads to a lowering of the laser contrast and luminance.

[0197] By employing the combination of the polycondensate of component B with carbon black in PA 66, an improved surface smoothness was obtained with improved mechanical properties, specifically tensile modulus, tensile strength, Charpy notched impact strength, and, most pronounced, Charpy unnotched impact strength.

[0198] For polyamide compositions, based on PA 6, by employing the polycondensate of component B and the carbon black an improved surface smoothness results, while retaining the mechanical properties (the tensile modulus is slightly increased).

[0199] Therefore, generally speaking, carbon black leads to good laser markability, but poor surface appearance, whereas nigrosine leads to a good surface smoothness, but poor laser inscribability. Combining the polycondensate component B with the carbon black component C in the polyamide molding compositions results in an improved laser contrast, improved luminance and therefore improved laser inscribability, in combination with improved surface smoothness.

[0200] According to the present invention, the advantageous effects are achieved without the need to use nigrosine or further colorants or pigments.