PROCESS FOR PLASTIC OVERMOLDING ON A METAL SURFACE AND PLASTIC-METAL HYBRIDE PART

Abstract

The invention relates to a process for manufacturing a plastic-metal hybrid part by overmolding of a moldable plastic material on a metal surface via nano-molding technology (NMT), wherein the moldable plastic material is a LDS composition comprising an LDS additive and a blend of a semi-crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide. The invention also relates to a plastic-metal hybrid part, obtainable by said process, wherein a metal part is overmolded by a LDS composition comprising a blend of a semi-crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide.

Claims

1) Process for manufacturing a plastic-metal hybrid part by plastic overmolding of a Laser Direct Structuring (LDS) composition on a metal surface via nano-molding technology (NMT), comprising steps of (i) providing a metal substrate having a surface area with surface irregularities of nano-size dimensions; (ii) providing an LDS composition; (iii) forming a plastic structure on the metal substrate by molding said LDS composition directly on at least a part of the surface area with the surface irregularities of the metal substrate; wherein the LDS composition comprises a Laser Direct Structuring (LDS) additive, a semi-crystalline semi-aromatic polyamide and an amorphous semi-aromatic polyamide.

2) Process according to claim 1, comprising steps of (i) subjecting a surface area of the plastic structure formed on the metal substrate to a laser beam, thereby activating the surface area subjected to the laser beam, and (ii) subjecting the plastic-metal hybrid part comprising an activated surface area obtained by step (iv) to an electroless plating process, thereby forming a metal based conductive pattern on the activated surface area.

3) Process according to claim 1, wherein the metal substrate is a stamped sheet metal substrate.

4) Process according to claim 1, wherein the metal substrate is formed from a material selected from the group consisting of aluminum, aluminum alloy, titanium, titanium alloy, iron, steel, magnesium, and magnesium alloy.

5) Process according to claim 1, wherein the process comprises a step prior to step i) of anodizing the metal substrate using an anodizing agent selected from the group consisting of chromic acid, phosphoric acid, sulfuric acid, oxalic acid, and boric acid.

6) Process according to claim 1, wherein the LDS composition comprises (A) 30-89 wt. % of the semi-crystalline semi-aromatic polyamide; (B) 10-40 wt. % of the amorphous semi-aromatic polyamide; and (C) 1-10 wt. % of the LDS additive, wherein the weight percentages (wt. %) are relative to the total weight of the composition.

7) Process according to claim 1, wherein the LDS composition comprises (A) 30-80 wt. % of the semi-crystalline semi-aromatic polyamide; (B) 10-30 wt. % of the amorphous semi-aromatic polyamide; (C) 1-10 wt. % of the LDS additive, and (D) 5-60 wt. % of a fibrous reinforcing agent or a filler, or a combination thereof; wherein the weight percentages (wt. %) are relative to the total weight of the LDS composition.

8) Process according to claim 1, wherein the LDS composition consists of (A) 30-70 wt. % of the semi-crystalline semi-aromatic polyamide; (B) 10-30 wt. % of the amorphous semi-aromatic polyamide; (C) 1-10 wt. % of the LDS additive; (D) 10-60 wt. % of a fibrous reinforcing agent or a filler, or a combination thereof; and (E) 0.1-20 wt. % of at least one other component; wherein the weight percentages wt. % are relative to the total weight of the composition.

9) Process according to claim 1, wherein the LDS additive comprises a spinel based metal oxide.

10) Plastic-metal hybrid part comprising a plastic material bonded to a metal part with a surface area having surface irregularities of nano-size dimensions, wherein the plastic material is a Laser Direct Structuring (LDS) composition comprising an LDS additive, a semi-crystalline semi-aromatic polyamide, and an amorphous semi-aromatic polyamide.

11) Plastic-metal hybrid part obtained by the process according to claim 1.

12) Plastic-metal hybrid part obtained by the process according to claim 6.

13) Plastic-metal hybrid part claim 10, wherein the plastic-metal hybrid part has a bonding force between the metal part and the plastic material, measured by the method according to ISO19095 at 23 C. and a tensile speed of 10 mm/min, in the range of 40-70 MPa.

14) Plastic-metal hybrid part according to claim 10, wherein the plastic material comprises a surface area comprising a metal based conductive pattern.

15) Plastic-metal hybrid part according to claim 10, wherein the part is a part for in medical applications, automotive applications, aerospace applications, military applications, RF antennas, sensors, security housings and connectors.

Description

[0107] FIG. 1. Schematic representation of the test samples, wherein the black part (A) is the plastic part, and the grey part (B) is the metal part.

BONDING STRENGTH TEST METHOD

[0108] The bonding strength methods for the adhesion interface in the plastic-metal assemblies was measured by the method according to ISO19095 at 23 C. and a tensile speed of 10 mm/min. The results have been included in Table 1.

LDS Performance

[0109] The LDS behavior was tested with a 20 W laser, applying different power levels ranging from 50% to 90% of the maximum laser power (max 20 W) and different pulsing frequencies (60 kHz, 80 kHz and 100 kHz), with a laser spot size of 40 m diameter. Plating was done with a standard Ethone Plating bath with Cu only with a plating time of 10 minutes. Plating thickness was measured with 300 micron diameter X-ray beam, averaged over 3 different measurements for each of the process conditions. The measurements were based on calibrated data for copper films with certified thickness values. Results are given in Table 1.

TABLE-US-00002 TABLE 1 Compositions and test results for Comparative Experiment A and Example I on aluminum plates (metal plates A). CE-C EX-I Composition (wt. %) sc-PPA 53 33 am-PPA 0 20 GF 40 40 LDS additive 5 5 Color MB 2 2 Total 100 100 Test Results Bonding Strength (MPa) Moderate Good Metal plating Good Good

[0110] The results show that the bonding strength for the composition according to the invention (Example I) comprising the amorphous semi-aromatic polyamide is better than for those for the corresponding Comparative Experiment A.