BLACK-COLOURED POLYAMIDE COMPOSITION WITH HIGH LASER TRANSMITTANCE FOR LASER WELDING APPLICATION

Abstract

Described herein is a polyamide composition, including (i) at least one aliphatic polyamide or semi-aromatic polyamide or mixture thereof; (ii) circular glass fibres; (iii) flat glass fibres; (iv) at least one black dye of the monoazo complex type; and (v) optionally one or more further additives.

Claims

1. A polyamide composition, comprising (i) 50 to 78.88 wt.-%, based on the total weight of the polyamide composition, of at least one aliphatic polyamide or semi-aromatic polyamide or mixture thereof; (ii) 20 to 50 wt.-%, based on the total weight of the polyamide composition, of circular glass fibres, (iii) 1 to 20 wt.-%, based on the total weight of the polyamide composition, of flat glass fibres; (iv) 0.02 to 1 wt.-%, based on the total weight of the polyamide composition, of at least one black dye of the monoazo complex type; and (v) 0.1 to 5 wt.-%, based on the total weight of the polyamide composition, of one or more further additives.

2. The polyamide composition according to claim 1, wherein the at least one aliphatic polyamide is selected from the group consisting of homopolymers of hexamethylenediamine and adipic acid (PA6.6), homopolymers of ε-caprolactam (PA6), copolymers of hexamethylenediamine, adipic acid and ε-caprolactam (PA6.6/6), homopolymers of hexamethylenediamine and sebacic acid (PA6.10) and mixtures of these aliphatic polyamides.

3. The polyamide composition according to claim 1, wherein the semi-aromatic polyamide is selected from the group consisting of homopolymers and/or copolymers of hexamethylenediamine and adipic acid with terephthalic acid and/or isophthalic acid.

4. The polyamide composition according to claim 3, wherein the at least one semi-aromatic polyamide is selected from the group consisting of copolymers of hexamethylenediamine, adipic acid and terephthalic acid (PA6.6/6.T), copolymers of hexamethylenediamine, adipic acid and isophthalic acid (PA6.6/6.I), copolymers of hexamethylenediamine, terephthalic acid and isophthalic acid (PA6.T/6.I), copolymers of hexamethylenediamine, adipic acid, terephthalic acid and isophthalic acid (PA6.6/6.T/6.I) and mixtures of these semi-aromatic polyamides.

5. The polyamide composition according to claim 1, wherein the black dye of the monoazo complex type is C.I. Solvent Black 27.

6. The polyamide composition according to claim 1, wherein the at least one additive is selected from the group consisting of colorants, mould release agents, flame retardants, toughening modifiers, and additives to facilitate the mixing of the components or the moulding of the composition.

7. (canceled)

8. (canceled)

9. A molded part obtained from the polyamide composition according to claim 1.

Description

EXAMPLES

Preparation of the Polyamide Compositions:

[0088] As examples and comparative examples, several polyamide compositions were prepared.

[0089] The following components were used as starting materials:

Component (i): PA6.6 homopolymer
Component (ii): glass fibre chopped strands having an average length of 4.5 mm and an average diameter of 10 μm (T435R from Taishan)
Component (iii): flat glass fibers ECS301-HP-3-M3 having an aspect ratio of 4:1 available from Chongqing Polycomp International Corp.
Component (iv): monoazo complex dye Solvent Black 27
Component (v): heat stabilizer and mould release masterbatch (MM9549C from Solvay)

[0090] Compositions for moulding according to the invention were prepared by mixing in a twin-screw type extruder ZSK 18 W at a rate of 12 kg/h and a rotation speed of equal screw 300 rev/min, at a temperature in the range of from 265° C. to 340° C., depending on the formulation of the various components and amounts as disclosed in Table 1 below.

[0091] Plaques of different sizes and thickness were produced by injection moulding.

[0092] The following properties were determined:

Tensile Modulus, Tensile Strength and Tensile Elongation:

[0093] Tensile modulus and tensile strength were determined according to ISO 527-2/1A. Values are given in MPa. The tensile elongation was determined according to ISO 527-2/1A. Values are given in %.

Flexural Modulus and Flexural Strength:

[0094] Determination of flexural strength at maximum load was carried out according to ISO 178 with test samples having a size of 80×10 mm and a thickness of 4 mm. Values are given in MPa.

Charpy Unnotched Impact Strength:

[0095] Charpy unnotched impact strength was determined according to ISO 179/1eU with test samples having a size of 80×10 mm and a thickness of 4 mm. Values are given in kJ/m.sup.2.

Charpy Notched Impact Strength:

[0096] Charpy notched impact strength was determined according to ISO 179/1eA with test samples having a size of 80×10 mm and a thickness of 4 mm. A 0.8 mm-wide U-shaped notch was made on the broad side of the specimens. The notch depth was ⅓ of the specimen thickness. The edges outlining the notch root had a curvation radius of <0.1 mm. Values are given in kJ/m.sup.2.

Heat Deformation Temperature:

[0097] Heat deformation temperature was determined at 1.82 MPa according to ISO 75/Af. Values are given in ° C.

Laser Transmittance at 980 and 1064 nm:

[0098] Laser transmittance was determined by means of a UV-visible Spectrophotometer (Mettler Evolution 220) with test plaques of 60×60 mm size.

Colour L*, a*, b* Values, 2 mm:

[0099] Colour L*, a*, b* values were determined by means of a Benchtop Spectrophotometer (model Ci7800 manufactures by X-rite®, Inc.) in colour test mode using 90×60×2 mm flat specimens.

Results of the Tests:

[0100] The results of the tests for Examples E1 to E4 and Comparative Example C1 are summarized in Table 1.

TABLE-US-00001 Formulation Raw RMS Material code Unit Supplier C1 E1 E2 E3 E4 Polyamide 6.6 26AE1 % Solvay 69.5 69.5 69.5 69.5 69.5 Heat stabilizer and Mold MM9549C % Solvay 0.4 0.4 0.4 0.4 0.4 release master Batch C.I. Solvent Black 27 Black H % Clariant 0.1 0.1 0.1 0.1 0.1 Standard Glass fibres T435R % Taishan 30 29 28 25 15 Flat Glass fibres ECS301HP-3-M3 % CPIC 1 2 5 15 Sum % 100 100 100 100 100 Properties Unit Standard Ten Moduls MPa ISO 527-2/1A 12670 10325 10174 10268 10278 Tens Strength MPa ISO 527-2/1A 199.8 196 189 189 190 Tens Elongation % ISO 527-2/1A 3.43 3.5 3.5 3.5 3.2 Flex Modulus MPa ISO 178 8990 8886 8805 8740 8714 Flex Strength MPa ISO 178 285.5 294 283 282 278 Charpy Unnotched Impact KJ/m.sup.2 ISO 179/1eU 12 12 12 12 13 Charpy Notched Impact KJ/m.sup.2 ISO 179/1eA 65 88 83 78 75 Heat Deformation ° C. ISO 75/Af 243 247 247 246 247 Temperature 1.82 MPa Laser Transmittance at % 72.7 73.9 74.7 75.8 75.9 980 mn, 1.2 mm plaque Laser Transmittance at % 46.9 53.4 52.3 53.7 54.3 980 mn, 2 mm plaque Laser Transmittance at % 31.1 37 34.9 37.8 40.9 980 mn, 3.2 mm plaque Laser Transmittance at % 74.8 75.8 76.5 77.6 77.5 1064 mn, 1.2 mm plaque Laser Transmittance at % 49.8 56.1 55.2 56.5 57.2 1064 mn, 2 mm plaque Laser Transmittance at % 33.9 40 37.6 40.8 44.2 1064 mn, 3.2 mm plaque Colour L* Value, 2 mm 28.88 27.8 28.32 27.83 28.78 Colour a* Value, 2 mm 0.95 0.56 0.47 0.54 0.36 Colour b* Value, 2 mm −6.68 −4.5 −4.74 −4.34 −5.09

[0101] Table 1 shows a synergistic effect achieved by the use of standard glass fibers together with flat glass fibres. At a total amount of 30 wt.-% glass fibres, substituting 1 wt.-%, 2 wt.-%, 5 wt.-% and 15 wt.-%, respectively, of standard glass fibers with flat glass fibres, significantly improves the laser transmittance of the polyamide plaques at 980 nm and 1064 nm. The effect is most pronounced with the 3.2 mm plaques. Concurrently, a good level of mechanical properties is maintained.