Process for producing a metal-plastic hybrid component

Abstract

The invention provides a process for producing a hybrid component comprising metal and plastic. The process comprises the steps of a) pretreating the metal surface by applying at least one conversion layer, b) applying at least one layer of an adhesion promoter composition and c) bonding the metal to the plastic. The adhesion promoter composition comprises at least one copolyamide-based hotmelt adhesive.

Claims

1. A process for producing a hybrid component comprising metal and plastic, the process comprising: pretreating a metal surface by applying at least one conversion layer; applying at least one layer of an adhesion promoter composition; and bonding the metal to the plastic, wherein the adhesion promoter composition comprises at least one copolyamide-based hotmelt adhesive and does not comprise a functionalized polyolefin, and the hybrid component has a bond strength in a range of from 6.2 to 16.0 MPa.

2. The process of claim 1, wherein the copolyamide-based hotmelt adhesive comprises a copolyamide, at least one epoxy component, and at least one blocked polyisocyanate.

3. The process of claim 1, wherein the plastic has been reinforced.

4. The process of claim 3, wherein the plastic has been reinforced by fibers.

5. The process of claim 1, wherein a converting agent is used to produce the conversion layer.

6. The process of claim 5, wherein the converting agent comprises halides.

7. The process of claim 6, wherein the converting agent comprises fluorides.

8. The process of claim 5, wherein the converting agent comprises halide salts, complex halides or mixtures thereof.

9. The process of claim 1, wherein in the bonding, the plastic is applied to the coated metal by injection moulding, pressing, laminating, in-mould coating or (co)extrusion.

10. The process of claim 1, wherein the conversion layer is obtained by a process comprising treating the metal surface with a plasma jet produced by using an operating gas and/or a flame jet produced by using a combustion gas, wherein at least one precursor material is introduced into the operating gas and/or the plasma jet or into the combustion gas and/or the flame jet such that the precursor material is reacted in the plasma jet or flame jet to form a reaction product and that the reaction product is deposited on the metal surface and/or on at least one layer disposed on the metal surface to coat the metal surface and/or the at least one layer.

11. The process of claim 1, wherein the metal comprises an iron-containing alloy.

12. The process of claim 1, wherein the metal comprises steel.

13. The process of claim 1, wherein the plastic comprises at least one selected from the group consisting of a polybutylene terephthalate, a polyolefin, a polycarbonate, a polyurethane, an aliphatic or semiaromatic polyamide, acrylonitrile-butadiene-styrene, and polymethylmethacrylate.

14. The process of claim 1, wherein the at least one copolyamide-based hotmelt adhesive in the adhesion promoter composition comprises a copolyamide, an epoxy component, and a blocked polyisocyanate.

Description

EXAMPLES

(1) Unpretreated sheets of various metal alloys were pretreated with converting agents. The following converting agents were used: A: Granodine 958 A from Henkel, Germany, comprising inter alia phosphoric acid and zinc bis(dihydrogenphosphate) B: Granodine 958 A from Henkel, Germany, additionally comprising 170 ppm Grano Toner 38 from Henkel, Germany (component comprising fluoride and hydrogendifluoride anions), C: Granodine 1455 T from Henkel, Germany, comprising inter alia phosphoric acid and dihydrogenhexafluorotitanate, and D: Alodine 4595 from Henkel, Germany, comprising inter alia dihydrogenhexafluorozirconate.

(2) The following metal alloys were used: M1: HDG EA (sheet thickness 0.6 mm) to DIN EN10142 M2: DX56D Z140 (sheet thickness 1.0 mm) to DIN EN10346 M3: DX51D Z140 (sheet thickness 1.0 mm) to DIN EN10346 M4: AlMg3 EN AW-5754 H111 to DIN EN 573-3 M5: Steel ZSTE 800 to DIN EN10142

(3) The conversion solution was applied in accordance with manufacturer's instructions by means of immersion into the solutions and drying of the layers, and then the metal samples were coated with an adhesion promoter composition. The composition applied comprised I: Copolyamide-based hotmelt adhesive comprising an epoxy component and a blocked polyisocyanate in the form of powder coating, II: Solvent-containing spray coating A comprising 29% by weight of a copolyamide-based hotmelt adhesive comprising an epoxy component and a blocked polyisocyanate and III: Solvent-containing spray coating B comprising 30% by weight of a copolyamide-based hotmelt adhesive comprising an epoxy component and a blocked polyisocyanate. IV: Copolyamide-based hotmelt adhesive (Vestamelt Z2366-P1 from Evonik Industries AG) comprising an epoxy component and a blocked polyisocyanate, and also a functionalized polyolefin, as powder coating.

(4) The four compositions 1 to 4 comprise the same hotmelt adhesives.

(5) The coating system was applied by the spray process with a layer thickness of from 50 to 70 m, and the powder coating was applied electrostatically with a layer thickness of from 50 to 100 m. The spray coating system and powder coating were stoved at 150 C. for 5 min. For this purpose, the coated metal sheets were placed in a preheated autoclave (oven).

(6) After the stoving procedure, guillotine shears were used to cut the metal sheets into strips fitting the injection moulding cavity with dimensions 24.9 mm59.8 mm (tolerance 0.2 mm).

(7) For production of the final hybrid components, the strips were then placed in a temperature-controlled injection mould and in-mould-coated with a thermoplastic. The following moulding compositions were used as plastics component:

(8) K1: PA6GF30 Durethan BKV30 H2.0 from LANXESS Deutschland GmbH

(9) K2: PA610GF30 VESTAMID Terra HS1850 from Evonik Industries AG

(10) K3: PA1010GF65 VESTAMID Terra BS1429 from Evonik Industries AG

(11) K4: PAl2GF30 VESTAMID L-GF30 from Evonik Industries AG.

(12) K5: VESTAMID LX9012 from Evonik Industries AG

(13) K6: PA6TGF50 VESTAMID HTplus M1035 from Evonik Industries AG

(14) K7: PACM12 TROGAMID CX7323 from Evonik Industries AG

(15) K8: PPLGF30 Celstran PP-GF30-05CNO1 from TICONA

(16) K9: PA6.6 Durethan A30S from LANXESS Deutschland GmbH

(17) K10 PBTGF30 VESTODUR GF30 from Evonik Industries AG

(18) The plastics were processed in an Allrounder 420 (screw diameter 25 mm) at a melt temperature of 280 C., a mould temperature of 80 C. or 120 C., and an injection rate of about 30 ccm/s. However, for the PPAGF50 and PPLGF30, mould temperatures were 120 C. and 70 C. respectively, and melt temperatures used were 335 C. and 270 C. respectively. It was important here to provide an injection delay of about 30 s, so that the metal sheet strip inserted could be preheated to mould temperature, giving a favourable effect on adhesion. After demoulding, the individual tensile shear test samples were separated from the sprue.

(19) The test samples used had the following physical features:

(20) TABLE-US-00001 Thickness Thickness Length Width Overlap in of metal of plastics Type in mm in mm mm.sup.2 sheet in mm component 1 130 25 25 25 0.6 or 1 4 mm 2 130 25 12.5 25 0.6 or 1 4 mm 3 100 20 20 20 1.5 6 mm (4 mm in the overlap region)

(21) The test samples thus produced were stored at 50% relative humidity for at least 24 h at 23 C. in order to ensure a uniform state of conditioning. The test samples are then clamped into a standard Zwick/Roell Z-020 tensile tester and tested with a velocity of 5 mm/min at 23 C. with a distance between the clamps and the overlap region of about 15 mm/side.

(22) TABLE-US-00002 Temp. Overlap in Bond strength Steel CA AP Plastic in C. mm in MPa M1* none I K1 80 25 25 1.2 M1 A I K1 80 25 25 4.1 M1 B I K1 80 25 25 7.2 M1* none I K1 120 25 25 1.7 M1 A I K1 120 25 25 6.7 M1 B I K1 120 25 25 8.4 M1 A II K1 120 25 25 5.3 M1 B II K1 120 25 25 6.2 M2 C II K1 120 25 25 7.4 M1 A III K1 120 25 25 8.0 M1 B III K1 120 25 25 8.3 M2 C III K1 120 25 25 8.8 M1 A I K1 80 12.5 25 11.2 M1 B I K1 80 12.5 25 13.1 M1 A II K1 80 12.5 25 13.9 M1 B II K1 80 12.5 25 14.9 M1 A I K9 80 12.5 25 5.8 M1 B I K9 80 12.5 25 6.5 M1 A I K3 80 12.5 25 11.9 M1 B I K3 80 12.5 25 12.6 M1 A II K3 80 12.5 25 13.5 M1 B II K3 80 12.5 25 14.1 M4 A II K3 80 12.5 25 11.2 M4 B II K3 80 12.5 25 12.5 M4 A II K6 120 12.5 25 7.9 M4 B II K6 120 12.5 25 10.2 M4 A I K10 80 12.5 25 2.2 M4 B I K10 80 12.5 25 4.5 M4 D I K10 80 12.5 25 3.9 M4* none II K1 80 12.5 25 2.3 M4 A II K1 80 12.5 25 7.7 M4 B II K1 80 12.5 25 13.7 M4 D II K1 80 25 25 7.5 M4 D III K1 80 25 25 7.2 M4 D II K1 120 25 25 8.2 M4 D III K1 120 25 25 7.8 M3* B none K2 80 12.5 25 n.m. M3 B I K2 80 12.5 25 11.3 M3 B II K2 80 12.5 25 14.7 M4* B none K2 80 12.5 25 n.m. M4 B I K2 80 12.5 25 16.0 M4 B II K2 80 12.5 25 15.5 M3* B none K3 80 12.5 25 n.m. M3 B II K3 80 12.5 25 15.7 M4* B none K3 80 12.5 25 n.m. M4 B II K3 80 12.5 25 7.9 M3* B none K1 80 12.5 25 n.m. M3 B I K1 80 12.5 25 13.8 M3 B II K1 80 12.5 25 12.3 M4* B none K1 80 12.5 25 n.m. M4 B I K1 80 12.5 25 13.0 M4 B II K1 80 12.5 25 13.9 M4* B none K5 80 C. 25 25 n.m. M4 B I K5 80 C. 25 25 4.5 M3* B none K6 120 C. 12.5 25 1 M3 B II K6 120 C. 12.5 25 11.9 M3* B none K7 80 C. 25 25 n.m. M3 B I K7 80 C. 25 25 4.8 M3 B II K7 80 C. 25 25 3.7 M4* B none K8 70 C. 12.5 25 n.m. M4 B IV K8 70 C. 12.5 25 5.8 M5* B none K4 80 C. 20 20 n.m. M5 B I K4 80 C. 20 20 8.8 M5 B II K4 80 C. 20 20 10.6 *non-inventive n.m. = not measurable (no adhesion) CA: converting agent; AP: adhesion promoter composition; Temp: mould temperature

(23) The results show that the coating composed of conversion layer and adhesion promoter layer can achieve increased bond strength between metal and plastic in hybrid components compared to systems without a conversion layer. Bond strength is increased especially in the case of use of halide-containing, preferably fluoride-containing, converting agents (converting agents B and C).