THERMALLY ACTIVATABLE, FAST CURING ADHESIVE COATING

Abstract

The present invention relates to a thermally activatable adhesive composition for use in a method for producing a stack of metal sheets from glued together sheet metal components, the use of the adhesive composition in a method for producing a stack of metal sheets from glued together sheet metal components, the method for producing a stack of metal sheets from glued together sheet metal components, a sheet metal component coated with the adhesive composition, and a stator or rotor core containing one or more of such sheet metal components.

Claims

1-15. (canceled)

16. A thermally activatable adhesive compound to use in a method for producing a stack of metal sheets from glued together sheet metal components containing: 100 parts by weight of an epoxy resin; 4 to 8 parts by weight of a latent curing agent; and 4 to 10 parts by weight of a latent accelerator.

17. A thermally activatable adhesive compound according to claim 16, further containing: 2 to 12 parts by weight of one or more anti-corrosion additives of zinc aluminum molybdate phosphates and/or strontium aluminum polyphosphates,

18. The adhesive compound according to claim 16, further containing: 5 to 15 parts by weight of one or more insulation additives of kaolin and/or mica.

19. The adhesive compound according to claim 16, further containing: 0.2 to 8 parts by weight of absorption additives of carbon blacks and/or iron oxide.

20. The adhesive compound according to claim 16, further containing one or more of the following: fillers, dispersants and film-forming agents.

21. The adhesive compound according to claim 16, characterized in that the epoxy resin is an aqueous dispersion of bisphenol A epoxy resin.

22. The adhesive compound according to claim 16, characterized in that the latent curing agent contains a dicyandiamide, an imidazole, a BF.sub.3 amine complex or a combination thereof.

23. The adhesive compound according to claim 16, characterized in that the latent accelerator contains a urea derivative and/or an imidazole.

24. The use of the adhesive compound according to claim 16 in a method for producing a stack of metal sheets from glued together sheet metal components.

25. A method for producing a stack of metal sheets from glued together sheet metal components, at least two sheet metal components being joined with an adhesive layer in between to form a composite body, characterized in that an adhesive compound according to claim 16, that is, thermally activated before or during joining, is used as an adhesive.

26. The method according to claim 25, characterized in that the thermal activation is done by means of infrared radiation.

27. The method according to claim 25, characterized in that one of the sheet metal component parts is coated with the adhesive compound before the joining is done to form the compound body, the adhesive compound hardening before the joining is done to form the compound body but not being cured such that the free surface of the adhesive layer does not have an adhesive property.

28. A sheet metal component coated with an adhesive compound according to claim 16.

29. The sheet metal component according to claim 28, characterized in that the sheet metal component is a steel sheet.

30. A stator or rotor core containing one or more sheet metal parts according to claim 28.

Description

EXAMPLES

[0059] Experiments were conducted with two products according to the invention (examples 1 and 2) and two comparable prior art products (Voltatex 1175W from Axalta and Dispercoll U 8755 from Bayer Materials Science).

[0060] Experimental Conditions:

[0061] Application of the adhesive to an electrical sheet steel, sheet thickness 0.3 mm

[0062] Layer thickness after drying process: 5-6 m

[0063] Sample geometry: 25 mm100 mm

[0064] Testing of lap shear strength based on DIN EN 1465

[0065] Overlapping length: 12.5 mm

[0066] Joining the samples in the hot press: 200 C., 1 s (see example 1)

[0067] or joining the samples by means of NIR radiation (0.3 s) (see example 2)

TABLE-US-00001 Baked enamel PU dispersion (Voltatex (Dispercoll Adhesive designation: 1175W) U8755) Example 1 Example 2 EpiRez 5108-W-60 100 parts 100 parts (bisphenol A epoxy resin) Dyhard 100 SF 6 parts 6 parts (dicyandiamide) Dyhard URAcc57 (urea 8 parts 8 parts derivative) Heucophos SAPP 8 parts 8 parts (strontium aluminum polyphosphate hydrate) Kaolin 15 parts 15 parts Iron oxide 2 parts Results: Joining process Hot press, Hot press, Hot press, NIR radiation, 200 C., 1 s 200 C., 1 s 200 C., 1 s 0.3 s, joining at RT Lap shear strength 0.5 MPa 1.7 MPa 6.1 MPa 6.3 MPa Lap shear strength 0 MPa 0 MPa 2.1 MPa 1.2 MPa at 190 C.

[0068] The experimental data proves that an adhesive compound according to the invention results in a lap shear strength of the obtained sheet metal composite that cannot be achieved by adhesive compounds of the prior art with the same activation time.