Foam Abrasive and Method for Producing Same

Abstract

A foam abrasive for grinding a workpiece includes a main part made of foam, in particular polyurethane foam, and abrasive grains which are fixed to at least one surface of the foam abrasive via a base binder made of thermoplastic polyurethane. The abrasive grains are covered with a cover binder.

Claims

1. A foam abrasive for abrasive working of a workpiece, comprising: a main body comprising foam; abrasive grains affixed on at least one surface of the foam abrasive by a make coat of thermoplastic polyurethane; and a size coat covering the abrasive grains.

2. The foam abrasive of claim 1, wherein the size coat includes a reactive one-component adhesive.

3. The foam abrasive of claim 1, wherein the size coat includes a two-component adhesive.

4. The foam abrasive of claim 1, wherein the size coat includes an acrylate adhesive, methacrylate adhesive, epoxy adhesive, or an adhesive based on a radical crosslinking ethylene-vinyl acetate copolymer.

5. The foam abrasive of claim 1, wherein the size coat has a surface weight of between 10 g/m.sup.2 and 80 g/m.sup.2.

6. The foam abrasive of claim 1, wherein the size coat has a Shore D hardness of between 30 and 90.

7. The foam abrasive of claim 1, wherein the size coat has an ultimate tensile strength of between 5 MPa and 65 MPa.

8. The foam abrasive of claim 1, wherein the size coat has an elongation at break of more than 3%.

9. A method for producing a foam abrasive, comprising: coating a surface of a main body, which comprises foam, with a make coat of thermoplastic polyurethane; applying abrasive grains to the surface and affixing the abrasive grains via the make coat; applying a size coat in such a wav that the size coat covers the abrasive grains and the make coat.

10. The method of claim 9, wherein the applying of the size coat comprises: spraying the size coat; and subsequently curing the size coat.

11. The method of claim 9, wherein the size coat has a viscosity (at 25° C.) of between 150 mPa.Math.s and 8000 mPa.

12. The method of claim 11, wherein the viscosity of the size coat is between 200 mPa.Math.s and 4000 mPa s.

13. The method of claim 9, wherein the foam is a polyurethane foam.

14. The foam abrasive of claim 1, wherein the foam is a polyurethane foam.

15. The foam abrasive of claim 5, wherein the surface weight of the size coat is between 25 g/m.sup.2 and 35 g/m.sup.2.

16. The foam abrasive of claim 6, wherein the Shore D hardness of the size coat is between 65 and 75.

17. The foam abrasive of claim 7, wherein the ultimate tensile strength of the size coat is between 40 MPa and 55 MPa.

18. The foam abrasive of claim 8, wherein the elongation at break of the size coat is more than 15%.

Description

DRAWINGS

[0025] The invention is elucidated in more detail in the description below with reference to exemplary embodiments represented in the drawings. The drawings, the description and the claims contain numerous features in combination. The skilled person will expediently also consider the features individually and associate them to form rational further combinations. Identical reference symbols in the figures denote identical elements.

[0026] In the drawings

[0027] FIG. 1 shows a detail from a schematic sectional representation of one exemplary embodiment of the foam abrasive of the invention;

[0028] FIG. 2 shows an exemplary embodiment of a method for producing a foam abrasive of the invention.

[0029] FIG. 1 shows a detail from an illustrative exemplary embodiment of a foam abrasive 10 of the invention with abrasive grains 12 in a schematic sectional representation. In the embodiment represented, the foam abrasive 10 has a main body 14 in the form of a disk, with abrasive grains 12 disposed on the entire surface 16 thereof. The main body 14 has a thickness of 24 mm in cross section. The main body 14 consists of a polyurethane foam having an open-pore structure. The surface of the main body 14 has a roughness of less than 2.0 μm (here not represented more closely in enlarged form). The abrasive grains 12 are affixed on the surface 16 of the main body 14 by means of a make coat 18 of thermoplastic polyurethane (TPU). Additionally, over the resultant layer of make coat 18 and abrasive grains 12, there is an applied layer of size coat 20, which covers the abrasive grains 12. The size coat 20 is realized as a two-component adhesive based on polyurethane. The size coat 20 is applied on the surface 16 of the main body 14, coated with make coat 18, with a surface weight of 30 g/m.sup.2. Measured on a layer of size coat (not represented in more detail here), the size coat 20 has a hardness of 30 and a tensile strength of 40 MPa. The elongation at break of the size coat 20, measured on a separate 2 mm thick layer of the size coat 20 at 25° C., is 5%.

[0030] The foam abrasive 10 of the invention may be produced by means of a production method 100 represented in FIG. 2: [0031] method step 102: provision of a main body 14 of foam, more particularly of polyurethane foam, [0032] method step 104: coating of the main body 14 on the surface 16 with make coat 18 of thermoplastic polyurethane (TPU), with for example the parameter settings stated above, [0033] method step 106: application of abrasive grains 12 to the surface 16 and affixing by means of the make coat 18, [0034] method step 108: application—here more particularly sprayed application—of size coat 20, with the size coat 20 prior to spraying having a viscosity of 1000 mPa.Math.s, in such a way that the applied size coat 20 covers the abrasive grains 12 and the make coat 18, [0035] method step 110: curing of the layer of size coat 20 produced, with supply of heat at 170° C. for a duration of 20 seconds.