EPOXY RESIN-BASED CATHODIC ELECTRODEPOSITION (CED) OF METAL COMPONENTS AS AN ADHESION PROMOTER FOR PU SYSTEMS

Abstract

The present invention relates to a composite element, especially for a damping element, comprising a) at least one metallic body having a surface; b) a coating comprising an epoxy resin on at least part of the surface of the metallic body; c) a plastics body comprising at least one polyurethane, which at least partly surrounds the metallic body of (a) and in the region of the surround is at least partly in direct contact with the coating of (b), wherein the composite element between the surface of the metallic body (a) and the coating (b) has a conversion layer (d) which comprises at least one compound selected from the group of zirconium(IV) oxide, zinc(II) phosphate, and chromate. The invention further relates to a damping element comprising the composite element and at least one further body which is at least partly in direct contact with the composite element, preferably with the plastics body of (c). The invention additionally relates to production processes for composite element and damping element, to the composite and damping elements, respectively, that are produced or producible by these processes, and the use of these composite and damping elements, respectively.

Claims

1. A composite element, comprising: a) a metallic body having a surface; b) a coating comprising an epoxy resin on at least part of the surface of the metallic body of (a); and c) a plastics body comprising a polyurethane, which at least partly surrounds the metallic body of (a) and in a region of the surround is at least partly in direct contact with the coating of (b); wherein the composite element has, between the surface of the metallic body of (a) and the coating of (b), a conversion layer (d) which comprises a compound selected from the group consisting of zirconium(IV) oxide, zinc(II) phosphate, and chromate.

2. The composite element of claim 1, wherein the epoxy resin of (b) is an epoxy resin which is obtained or obtainable from a water-containing epoxy resin dispersion which optionally comprises more than 50 weight % of water, based on a total weight of the water-containing epoxy resin dispersion.

3. The composite element of claim 2, wherein the water-containing epoxy resin dispersion comprises an epoxy resin having ammonium groups, obtained or obtainable by: A) reacting at least i) a precursor prepared or preparable, with addition of a phosphine and/or phosphine salt as catalyst, from i.a) a diepoxide compound; and i.b) a mono- or diphenol or a mixture of a mono- and a diphenol; and ii) an organic amine; at an addition temperature in a range of 60 to 130° C. to obtain an epoxide-amine adduct; B) subsequently or simultaneously reacting secondary hydroxyl groups, formed in the reaction of i.a) and i.b), with epoxide groups of the epoxide-amine adduct obtained in A), at a temperature of 110 to 150° C., C) adding a crosslinking agent at a temperature of <150° C., D) neutralizing; and E) dispersing a product obtained in A) to D) in water.

4. The composite element of claim 1, wherein the metallic body of (a) comprises an iron alloy or aluminum.

5. The composite element of claim 1, wherein the metallic body of (a) has a shape selected from the group consisting of disk, perforated disk, ring, cylinder, and hollow cylinder.

6. A damping element, comprising: (1) a composite element comprising a) a metallic body having a surface; b) a coating comprising an epoxy resin on at least part of the surface of the metallic body of (a); and c) a plastics body comprising a polyurethane, which at least partly surrounds the metallic body of (a) and in a region of the surround is at least partly in direct contact with the coating of (b); and (2) a further body which is at least partly in direct contact with the composite element of (1); wherein the composite element of (1) has, between the surface of the metallic body of (a) and the coating of (b), a conversion layer (d) which comprises a compound selected from the group of consisting of zirconium(IV) oxide, zinc(II) phosphate, and chromate.

7. The damping element of claim 6, wherein the further body of (2) comprises a coating (b′) comprising an epoxy resin on at least part of a surface of the further body.

8. The damping element claim 6, wherein the metallic body of (a) comprises an iron alloy or aluminum.

9. The damping element of claim 6, wherein the further body of (2) comprises a metallic body.

10. The damping element of claim 6, wherein the further body of (2) comprises a polyurethane.

11. A process for producing a composite element, wherein the composite element comprises a) a metallic body having a surface; b) a coating comprising an epoxy resin on at least part of the surface of the metallic body of (a); and c) a plastics body comprising a polyurethane, which at least partly surrounds the metallic body of (a) and in a region of the surround is at least partly in direct contact with the coating of (b); wherein the composite element has, between the surface of the metallic body of (a) and the coating of (b), a conversion layer (d) which comprises a compound selected from the group consisting of zirconium(IV) oxide, zinc(II) phosphate, and chromate; the process comprising: I) providing a coated metallic body having a surface and a coating comprising an epoxy resin on at least part of the surface of the coated metallic body; and II) embedding the coated metallic body of (I) into a plastics composition comprising a polyurethane, wherein the coated metallic body is at least partly surrounded by the plastics composition and the latter in a region of the surround enters at least partly into direct contact with the coating of (b).

12. A composite element obtained or obtainable by the process of claim 11.

13. A process for producing a damping element comprising: (1) a composite element comprising a) a metallic body having a surface; b) a coating comprising an epoxy resin on at least part of the surface of the metallic body of (a); and c) a plastics body comprising a polyurethane, which at least partly surrounds the metallic body of (a) and in a region of the surround is at least partly in direct contact with the coating of (b); wherein the composite element of (1) has, between the surface of the metallic body of (a) and the coating of (b), a conversion layer (d) which comprises a compound selected from the group consisting of zirconium(IV) oxide, zinc(II) phosphate, and chromate; and (2) a further body which is at least partly in direct contact with the composite element of (1); the process comprising II.1) introducing a metallic body having a surface and a coating comprising an epoxy resin on at least a part of the surface of the metallic body into a mold, II. 2) introducing the further body into the mold, with a part of the mold remaining empty; and II. 3) introducing a plastics composition into the part of the mold from (II.2) that has remained empty.

14. A damping element obtained or obtainable by the process of claim 13.

15. A process for producing an automotive component, the process comprising providing the composite element of claim 1.

16. A process for producing an automotive component, the process comprising providing the damping element of claim 6.

Description

DESCRIPTION OF THE FIGURES

[0370] FIG. 1 shows a perspective view of a coated metallic body 1, with the metallic body 2 being present here in the form of a ring which has a coating 3 comprising an epoxy resin on at least part of its surface;

[0371] FIG. 2 shows a section through a damping element 4, comprising a composite element 5 which has a plastics body 6 comprising at least one polyurethane and a coated metallic body 1, which is in turn at least partly surrounded by a further body 7, here a further plastics body 7;

[0372] FIG. 3 shows a metallic body 1 in the form of a (hollow) cylinder (inner sleeve), and a further, likewise metallic body 7 in the form of a further hollow cylinder (outer sleeve) for a round bearing, where the outer sleeve has a coating at least on part of its inner surface 8 (not shown) and the inner sleeve has a coating at least on part of its outer surface 9 (not shown);

[0373] FIG. 4 shows a section through a round bearing comprising an inner sleeve 1, an outer sleeve 7, and a plastics body 6 between inner and outer sleeves;

[0374] FIG. 5 shows, schematically, a sample body used for the study of the adhesive strength, where the numerical figures are to be understood as length figures in millimeters (e.g.

[0375] 12.5=12.5 mm), and where (a) shows a side view and (b) shows the corresponding front view;

[0376] FIG. 6 shows the results of the adhesive strength studies (lap shear strength) for an epoxy resin-coated metallic body+plastics body in comparison to a metallic body electroplated with ZnFe+plastics body;

[0377] FIG. 7 shows the results of the bursting force studies for a damping element based on an epoxy resin-coated metallic body+plastics body, in comparison to those for a damping element based on a metallic body electroplated with ZnFe+plastics body;

[0378] FIG. 8 shows, schematically, the apparatus (bursting test bearing) used for the bursting test studies;

[0379] FIG. 9 shows the results of the adhesive strength studies (lap shear strength) for a conversion-coated and epoxy resin-coated metallic body (aluminum)+plastics body in comparison to a metallic body (aluminum) which has only been conversion-coated+plastics body and in comparison to a metallic body (aluminum) which has been sandblasted and coated with a conventional PU adhesion promoter+plastics body;

[0380] FIG. 10 shows the results of the adhesive strength studies (lap shear strength) for a conversion-coated and epoxy resin-coated metallic body (steel)+plastics body in comparison to a metallic body (steel) which has only been conversion-coated+plastics body and in comparison to a metallic body (steel) which has been sandblasted and coated with a conventional PU adhesion promoter+plastics body.

CITED LITERATURE

[0381] U.S. Pat. No. 8,459,621 B1

[0382] EP 0 961 797 B1

[0383] EP 1 379 588 B1

[0384] EP 1 171 515 B1