Plastics moulding composition and use thereof

Abstract

A description is given of thermoplastic, white-pigmented plastics moulding compositions having improved mechanical properties, especially for LDS applications. The thermoplastic moulding composition consists of: (A) 20-88 wt % of a mixture consisting of (A1) 60-100 wt % of a thermoplastic (A2) 0-40 wt % of a mixture of (A2_1) 0-40 wt % of a thermoplastic other than (A1); (A2_2) 0-40 wt % of impact modifiers other than (A1) and (A2_1); (B) 10-70 wt % of fibrous adjuvants; (C) 0.1-10 wt % of an LDS additive or of a mixture of LDS additives, at least one LDS additive being selected from the following group: metal oxide based on copper, neodymium, molybdenum, bismuth, antimony or tin, with the proviso that spinels are excluded; metal phosphate; metal hydroxide phosphate; (D) 0.1-20 wt % of white pigment; (E) 0-20 wt % of particulate filler other than C and/or D; (F) 0-2 wt % of further, different additives;
the sum of (A)-(F) making up 100 wt %.

Claims

1. A thermoplastic moulding composition consisting of: (A) 43-80 wt % consisting of: (A1) a mixture of thermoplastics consisting of: (A1_1) 55-85 wt % of aliphatic polyamide selected from the group consisting of polyamide 1010, polyamide 610, polyamide 612, mixtures thereof, copolymers thereof, blends thereof and alloys thereof, (A1_2) 15-45 wt % of amorphous, partially aromatic polyamide, selected from the group consisting of: 6I/6T, 10I/10T, copolymers thereof, blends thereof, and alloys thereof, with a composition range T:I of 20:80 to 45:55, the sum of components (A1_1) and (A1_2) adding up to 100 wt % of component (A1); (B) 18-55 wt % of fibrous adjuvants in the form of glass fibres; (C) 1-6 wt % of an LDS additive or of a mixture of LDS additives, at least one LDS additive being selected from the following group: metal oxide based on antimony, copper, or tin or mixtures thereof, with the proviso that spinels are excluded; copper phosphate, tin phosphate, copper hydroxide phosphate, and tin hydroxide phosphate, (D) 1-5 wt % of white pigment formed exclusively by zinc sulphide; (E) 0 wt % of particulate filler other than C or D; (F) 0-2 wt % of further, different additives; the sum of (A) (F) making up 100 wt %.

2. The moulding composition according to claim 1, wherein component (C) is an LDS additive having an average particle size (d.sub.50) in the range of 50-20 000 nanometres.

3. A component formed from a moulding composition according to claim 1.

4. The moulding composition according to claim 1, wherein the glass fibres of component (B) are present in the form of short fibres or in the form of continuous fibres.

5. The moulding composition according to claim 1, wherein the glass fibres of component (B) are present in the form of short fibres, in the form of chopped glass having a length in the range of 0.2-20 mm, or in the form of continuous fibres.

6. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres, in the form of E-glass fibres according to ASTM D578-00.

7. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres, in the form of E-glass fibres according to ASTM D578-00 with a non-circular cross-section.

8. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres, in the form of E-glass fibres according to ASTM D578-00 with a non-circular cross-section, the dimension ratio of the main cross-sectional axis to the secondary cross-sectional axis perpendicular thereto is more than in the range from 3 to 5.

9. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres, in the form of E-glass fibres according to ASTM D578-00 composed of 52-62% silicon dioxide, 12-16% aluminium oxide, 16-25% calcium oxide, 0-10% borax, 0-5% magnesium oxide, 0-2% alkali metal oxides, 0-1.5% titanium dioxide and 0-0.3% iron oxide.

10. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres, in the form of high-strength glass fibres based on the ternary system silicon dioxide-aluminium oxide-magnesium oxide or on the quaternary system silicon dioxide-aluminium oxide-magnesium oxide-calcium oxide.

11. The moulding composition according to claim 1, wherein component (B) is formed by glass fibres in the form of high-strength glass fibres based on the ternary system silicon dioxide-aluminium oxide-magnesium oxide or on the quaternary system silicon dioxide-aluminium oxide-magnesium oxide-calcium oxide, in which case they have the following composition: 58-70 wt %, silicon dioxide (SiO.sub.2), 15-30 wt %, aluminium oxide (Al.sub.2O.sub.3), 5-15 wt %, magnesium oxide (MgO), 0-10 wt %, calcium oxide (CaO) and 0-2 wt %, further oxides, including zirconium dioxide (ZrO.sub.2), boron oxide (B.sub.2O.sub.3), titanium dioxide (TiO.sub.2) or lithium oxide (Li.sub.2O) or a combination of these oxides.

12. The moulding composition according to claim 1, wherein component (C) is an LDS additive having an average particle size (d.sub.50) in the range of 300 to 5000 nanometres.

13. The moulding composition according to claim 1, wherein the fraction of component (D) is in the range of 2-5 wt %.

14. A component with electrical conductor tracks, formed from the moulding composition according to claim 1, wherein said component is a casing or casing part for portable electronic devices, or a medical device, or a sensor, or an RFID transponder or a part for the automotive sector.

15. A component with electrical conductor tracks, formed from the moulding composition according to claim 1, wherein said component is (i) a casing or casing part for portable electronic devices selected from the group consisting of PDAs, mobile telephones, and telecommunications devices, (ii) a casing or casing part for a device selected from the group consisting of personal computers and notebooks, (iii) a casing or casing part for a medical device selected from the group consisting of hearing devices, sensor technology, and RFID transponders, or (iv) parts for an automotive sector selected from the group consisting of airbag module and multi-function steering wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred embodiments of the invention are described below by means of the drawings; in the drawings:

(2) FIG. 1 shows the parameters of the laser structuring; and

(3) FIG. 2 shows a specimen plate after laser activation and metalizing.

DESCRIPTION OF PREFERRED EMBODIMENTS

(4) The invention is to be described hereinafter using specific working examples (B), and compared with the less effective systems of the prior art (VB). The working examples specified below serve to support the invention and to demonstrate the differences relative to the prior art, but they are not intended to limit the general subject matter of the invention, as defined in the claims.

Examples B1 to B17 and Comparative Examples VB1 to VB6

(5) The components specified in Tables 2 and 3 are compounded in a twin-screw extruder from Werner and Pfleiderer having a screw diameter of 25 mm, with specified processing parameters (cf. Table 1). The polyamide pellets along with the additives are metered into the intake zone, while the glass fibre is metered into the polymer melt via a side feeder 3 barrel units ahead of the die. The compounds are taken off as extrudate from a nozzle 3 mm in diameter, and pelletized after water cooling. The pellets were dried at 110 C. under a reduced pressure of 30 mbar for 24 hours. The compounded formulations are injection-moulded on an Arburg Allrounder 320-210-750 machine to give sample bodies with defined cylinder temperatures for zones 1 to 4 and with a defined mould temperature (see Table 1).

(6) TABLE-US-00001 TABLE 1 Compounding and injection moulding conditions for the inventive and comparative examples Compounding/processing parameters B1-B17, VB1-VB6 Compounding Barrel temperatures [ C.] 250-280 Screw speed [rpm] 200 Throughput [kg/h] 15 Injection moulding Cylinder temperatures [ C.] 280 Mould temperature [ C.] 80

(7) TABLE-US-00002 TABLE 2 Composition and properties of Examples B1 to B8 Units B1 B2 B3 B4 B5 B6 B7 B8 Composition PA1010 wt % 35.5 35.7 34.0 35.5 34.2 34.2 34.2 34.2 PA 6I/6T wt % 11.8 11.9 11.3 8.5 8.5 8.5 8.5 PA 10I/10T wt % 11.8 Glass fibre type B wt % 50 50 50 50 50 50 50 50 LDS additive 1 wt % 1.4 1.0 1.4 1.4 4 4 LDS additive 3 4 4 Zinc sulphide wt % 1.0 1.1 3.0 1.0 3 3 Titanium dioxide wt % 3 3 Irganox 1098 wt % 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Properties MET.sup.1) MPa 14 500 14 300 14 800 12 500 16 000 15 000 15 800 14 700 Tensile strength MPa 183 182 182 134 185 146 175 140 Elongation at break % 2.7 2.7 2.6 3.5 2.2 1.7 2.1 1.7 Impact strength 23 C. kJ/m.sup.2 82 85 81 83 64 42 57 46 Notched impact kJ/m.sup.2 17 17 15 20 15 8 12 10 strength 23 C. Metallizability % 97 91 97 97 100 100 88 91 (fraction of metallized fields) Colour (subjective white white white white white white white white colour impression) (green) Colour lightness 72 73 79 76 80 82 70 75 L* .sup.1)MET = Modulus of Elasticity in Tension

(8) TABLE-US-00003 TABLE 3 Composition and properties of comparative examples VB1 to VB6 and B9 Units VB1 VB2 VB3 VB4 VB5 VB6 B9 Composition PA1010 wt % 36.6 36.6 36.6 52.4 44.4 34.2 42.7 PA 6I/6T wt % 9.1 9.1 9.1 13.3. 11.3 8.5 LDS additive 1 wt % 4 LDS additive 2 wt % 4 4 4 4 4 4 Glass fibre type A wt % 50 Glass fibre type B wt % 50 30 30 50 50 Glass fibre type C wt % 50 Zinc sulphide wt % 3 Titanium dioxide wt % 3 Talc wt % 10 Irganox 1098 wt % 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Properties MET.sup.1) MPa 14 400 14 300 16 100 8 300 11 000 14 000 15 600 Tensile strength MPa 145 146 167 111 122 116 178 Elongation at break % 1.9 2.2 2.4 2.5 1.9 1.5 2.2 Impact strength 23 C. kJ/m.sup.2 58 56 58 42 38 32 68 Notched impact kJ/m.sup.2 11 10 11 9 8 7 16 strength 23 C. Metallizability % 100 100 100 100 100 100 91 (fraction of metallized fields) Colour (subjective black black black black black grey white colour impression) Colour lightness L* 31 31 32 31 32 42 82 .sup.1)MET = Modulus of Elasticity in Tension

(9) TABLE-US-00004 TABLE 4 Composition and properties of examples B10 to B17 Units B10 B11 B12 B13 B14 B15 B16 B17 Composition PA 6 wt % 34 PA 66 wt % 32.5 8 48 15 PA 610 wt % 32.5 48 40 33 PA 612 wt % 32.5 PA 6I/6T wt % 11 10.5 10.5 16 10.5 16 16 16 Glass fibre type B wt % 50 50 50 30 50 30 30 30 LDS additive 1 wt % 3.5 LDS additive 4 wt % 1.2 1.2 3.5 4 4 4 4 LDS additive 5 wt % 2.5 4.0 Zinc sulphide wt % 1.0 3.2 1.7 1.7 1.7 1.7 Titanium dioxide wt % 1.5 3.2 Irganox 1098 wt % 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Properties MET MPa 15 500 16 600 14 200 8 600 15 300 8 800 9 500 9 200 Tensile strength MPa 153 170 152 130 164 130 146 132 Elongation at break % 1.8 1.7 2.0 2.6 2.1 2.3 2.1 2.4 Impact strength 23 C. kJ/m.sup.2 40 40 50 35 66 35 32 38 Notched impact kJ/m.sup.2 10 8 9 8 8 8 7 9 strength 23 C. Metallizability % 88 91 91 97 94 100 97 100 (fraction of metallized fields) Colour (subjective white white white white white white white white colour impression) Colour lightness 74 76 82 76 84 77 76 77 L*

(10) Key, Materials: PA 6I/6T (70:30) Amorphous, partially aromatic polyamide based on terephthalic acid, isophthalic acid and 1,6-hexanediamine, having a glass transition temperature of 125 C. and a solution viscosity of 1.54. PA 10I/10T (60:40) Amorphous, partially aromatic polyamide based on 1,10-decanediamine, isophthalic acid and terephthalic acid, having a glass transition temperature of 101 C. and a solution viscosity of 1.59. PA 1010 Partially crystalline, aliphatic polyamide based on 1,10-decanediamine and sebaccic acid, having a melting point of 200 C. and a solution viscosity of 1.78. PA 6 Partially crystalline, aliphatic polyamide based on caprolactam, having a melting point of 225 C. and a solution viscosity of 1.90. PA 66 Partially crystalline, aliphatic polyamide based on 1,6-hexanediamine and adipic acid, having a melting point of 260 C. and a solution viscosity of 1.85. PA 610 Partially crystalline, aliphatic polyamide based on 1,6-hexanediamine and sebaccic acid, having a melting point of 223 C. and a solution viscosity of 1.88. PA 612 Partially crystalline, aliphatic polyamide based on 1,6-hexanediamine and dodecanedioic acid, having a melting point of 217 C. and a solution viscosity of 1.84. Glass fibre type A Vetrotex 995 chopped E glass fibres, with a length of 4.5 mm and a diameter of 10 m (circular cross-section) from Owens Corning Fiberglass Glass fibre type B CSG3PA-820 chopped E glass fibres, with a length of 3 mm, a principal cross-sectional axis of 28 m, a secondary cross-sectional axis of 7 m, an axial ratio of 4 (non-circular cross-section) from NITTO BOSEKI, Japan Glass fibre type C: GF O.C. HPXSS PAX95 10-4 (Owens Corning (US)) LDS additive 1 Iriotec 8825, tin oxide and antimony oxide on mica, Merck LDS additive 2 Copper chromite, (Shepherd) LDS additive 3 Tin-based metal phosphate, Fabulase 330 (Budenheim) LDS additive 4 Irotec 8850, tin/antimony oxide on titanium dioxide, Merck LDS additive 5 Minatec 230 A-IR, tin antimony cassiterite (CAS 68187-54-2), Merck Titanium dioxide KRONOS 2222 titanium dioxide, white pigment. >92.5% titanium dioxide. Rutile. Coating: Al, Si, polysiloxane. d.sub.50 0.21 m. D 4.0 g/cm.sup.3. Zinc sulphide Sachtolith HD-S zinc sulphide (Sachtleben), average particle size in the range from 0.30 to 0.35 m. Talc Microtalc IT Extra Mondo Minerals

(11) The measurements were carried out in accordance with the following standards and on the following test specimens.

(12) (Thermo-)Mechanical Parameters:

(13) The modulus of elasticity in tension was determined in accordance with ISO 527 with a tensioning speed of 1 mm/min, and the yield stress, tensile strength and elongation at break were determined according to ISO 527 with a tensioning speed of 5 mm/min (non-reinforced versions) or with a tensioning speed of 5 mm/min (reinforced versions) at a temperature of 23 C., the sample body used being an ISO tension dumbbell, standard: ISO/CD 3167, Type A1, 17020/104 mm.

(14) Impact strength and Charpy notched impact strength were measured according to ISO 179 on an ISO test rod, standard: ISO/CD 3167, Type B1, 80104 mm at 23 C. temperature.

(15) The thermal characteristics (melting temperature (T.sub.m), enthalpy of fusion (H.sub.m), glass transition temperature (T.sub.g)) were determined on the basis of ISO standard 11357-11-2 on the pellets. Differential Scanning calorimetry (DSC) was carried out with a heating rate 20 C./min. For the glass transition temperature (T.sub.g), the temperature for the middle stage or point of inflection is reported.

(16) The relative viscosity (.sub.rel) was measured according to DIN EN ISO 307 at 20 C. using 0.5 wt % strength m-cresol solutions. The sample used comprises pellets.

(17) Deviations from this are stated in the description.

(18) The heat distortion resistance in the form of HDT A (1.8 MPa) and HDT B (0.45 MPa) was determined according to ISO 75 on ISO impact rods with dimensions of 80104 mm.

(19) Laser Structurability:

(20) In order to assess the metalizing behaviour, injection mouldings (plate 60602 mm) were structured using an Nd:YAG laser and thereafter subjected to electroless metallization in a copperizing bath. In the laser structuring, 18 adjacent regions measuring 44 mm on the surface of the moulding were irradiated. Laser structuring took place using a Trumpf TruMark Station 5000 laser at a wavelength of 1064 nm with a speed in the range from 300 to 7200 mm. In the course of this structuring, variations were made both in the pulse frequency, as in the range of 10-80 kHz, and in the hatch (pulse overlap), in the range from 0.03 to 0.09 mm. Following the laser structuring, the mouldings are subjected to a cleaning operation in order to remove laser processing residues. The mouldings then pass in succession through ultrasound baths with surfactant and with deionized water. After cleaning, the mouldings are metallized in succession in reductive copperizing baths (MID Copper 100 XB Strike and MID Copper 100 XB Build, Mac Dermid) at 55 to 65 C. The residence time in the strike bath is 20 min and in the build bath is 1-3 h. The rate of copper deposition (thickness of the copper layer) in the MID Copper 100 XB Build bath on the laser-irradiated areas amounts on average to 3 to 5 m/h.

(21) Metalizability:

(22) The metalizability was calculated as the ratio between metallized fields and the total number of fields. In total, 32 fields per sample plate are structured with the laser using different parameters, as shown in FIG. 1, and are subsequently metallized as described above. Metallized fields are only those fields which were metallized completely and uniformly in the operation described above. FIG. 2 shows a sample plate after laser structuring and metalizing, in which the fields beneath the diagonal from the bottom left to the top right were either not metallized or not sufficiently metallizedthat is metallized incompletely or non-uniformly.

(23) For all moulded interconnect device (MID) technologies, chemical reductive copper deposition is the key initial metalizing operation which is decisive for the quality of the overall layer. It is therefore entirely adequate to assess the quality of the primary metal layer. In order to arrive at the completed MID part, generally nickel and subsequently a final layer of immersion gold will be deposited on the basis of the first copper layer (primary layer). It will be appreciated that other metal layers as well, such as further layers of copper, palladium, tin or silver, may also be applied to the primary layer.

(24) Colour Lightness L*:

(25) The CIE L*a*b* values (DIN 6174) of sample bodies with dimensions of 24050 mm (colour plaques) were determined using a Datacolor spectrophotometer (instrument designation: Datacolor 650) against a white-coated metal contrast panel, under measuring conditions as follows: measurement mode: reflection, measurement geometry: D/8, illuminant: D 65 10, gloss: included, calibration: UV-calibrated, aperture plate: SAV. The colour plaques used for colorimetry were injection-moulded from the materials of the inventive and comparative examples on an all-electric injection-moulding machine from Arburg (apparatus designation: ARBURG Allrounder 320 A 500-170) with heated mould. The injection moulding parameters are listed in Table 1.

(26) The inventive examples, for which LDS additive 1 or 3 was used, have significantly better mechanical properties, more particularly a higher tensile strength, elongation at break, impact strength and notched impact strength, than the comparative attempts produced using LDS additive 1, particularly when white pigments are used at the same time, as shown by the comparison of B6 with VB6. In parallel to this, the moulding compositions of the invention have the same or similarly good metalizability and have a lighter intrinsic colour, as reflected in much higher colour lightness values L*. Thus for VB6 metalizability of 100% and a colour lightness L* of 42 are found, whereas for B6 the metalizability is likewise 100%, but the colour lightness adopts a much higher value, of 82. Comparing B5 with B6 and B7 with B8 it is found that with the same LDS additive, using zinc sulphide as white pigment instead of titanium dioxide, the mechanical properties that result are consistently better.