Process for the laser treatment of coatings

Abstract

The present invention relates to a process for the laser treatment of effect pigment-containing coatings, to coatings produced using this process, and to the use thereof in decorative and security products.

Claims

1. A process for modifying the optical properties of an effect pigment-containing coating, said process comprising: irradiating a coating (A) comprising at least one binder, at least one effect pigment, and one or more IR radiation-absorbent components using an IR laser, whereby solely said one or more IR radiation-absorbent components are partly or completely displaced from irradiated areas of said coating (A) and/or partly or completely oxidized and/or partly or completely bleached in said irradiated areas of said coating (A), and where, in the irradiated areas, said at least one effect pigment which was previously covered by said one or more IR radiation-absorbent components are partly or completely uncovered due to the partial or complete removal, oxidizing, and/or bleaching of said one or more IR radiation-absorbent components by the laser irradiation.

2. The process according to claim 1, wherein said one or more IR radiation-absorbent components are partly or completely displaced from the irradiated areas of the coating (A).

3. The process according to claim 1, wherein said at least one effect pigment is at least one pearlescent pigment, interference pigment, metal-effect pigment and/or liquid-crystal pigment.

4. The process according to claim 3, wherein said at least one effect pigment comprises a support and at least one coating wherein said support is a flake-form support comprising natural mica, synthetic mica, glass, calcium aluminum borosilicate, SiO.sub.2, or Al.sub.2O.sub.3, and said at least one coating comprises TiO.sub.2, a titanium suboxide, a titanium oxynitride, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4, SnO.sub.2, Sb.sub.2O.sub.3, SiO.sub.2, Al.sub.2O.sub.3, MgF.sub.2, ZrO.sub.2, B.sub.2O.sub.3, Cr.sub.2O.sub.3, ZnO, CuO, NiO or mixtures thereof.

5. The process according to claim 3, wherein said one or more IR radiation-absorbent components are selected from carbon blacks, phthalocyanines and mixtures thereof.

6. The process according to claim 1, wherein said irradiating is carried out imagewise.

7. The process according to claim 6, wherein three-dimensional patterns are produced by said laser irradiation.

8. The process according to claim 1, wherein said at least one IR radiation-absorbent component are selected from carbon blacks, phthalocyanines, and mixtures thereof.

9. The process according to claim 1, wherein said IR laser has a wavelength of 0.65-10.6 μm, and is operated in pulsed mode with a pulse frequency of 40-100 kHz.

10. The process according to claim 1, wherein said coating comprises a binder, said at least one effect pigment in an amount between 1 and 35 per cent by weight, based on the particle mass concentration of the dry coating, and said one or more IR radiation-absorbent components in an amount between 0.1 and 10 per cent by weight, based on the particle mass concentration of the dry coating.

11. The process according to claim 10, wherein said coating comprises said at least one effect pigment in an amount between 3 and 30 per cent by weight, based on the particle mass concentration of the dry coating, and said at least one IR radiation-absorbent component in an amount between 0.2 and 5 per cent by weight, based on the particle mass concentration of the dry coating.

12. The process according to claim 10, wherein said at least one effect pigment comprises a support and at least one coating wherein said support is a flake-form support comprising natural mica, synthetic mica, glass, calcium aluminum borosilicate, SiO.sub.2, or Al.sub.2O.sub.3, and said at least one coating comprises TiO.sub.2, a tita-nium suboxide, a titanium oxynitride, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4, SnO.sub.2, Sb.sub.2O.sub.3, SiO.sub.2, Al.sub.2O.sub.3, MgF.sub.2, ZrO.sub.2, B.sub.2O.sub.3, Cr.sub.2O.sub.3, ZnO, CuO, NiO or mixtures thereof, and wherein said one or more IR radiation-absorbent components are selected from carbon blacks, phthalocyanines and mixtures thereof.

13. The process according to claim 12, wherein said coating comprises said at least one effect pigment in an amount between 3 and 30 per cent by weight, based on the particle mass concentration of the dry coating, and said one or more IR radiation-absorbent components in an amount between 0.2 and 5 per cent by weight, based on the particle mass concentration of the dry coating.

14. The process according to claim 1, wherein said one or more IR radiation-absorbent components are partly or completely bleached in the irradiated areas of the coating (A).

15. The process according to claim 14, wherein said one or more IR radiation-absorbent components are selected from carbon blacks, phthalocyanines and mixtures thereof.

16. The process according to claim 1, wherein said at least one effect pigment has a flake-form support comprising natural mica, synthetic mica, glass, calcium aluminum borosilicate, SiO.sub.2, or Al.sub.2O.sub.3, and at least one coating on said flake-form support selected from TiO.sub.2, titanium suboxides, titanium oxynitrides, Fe.sub.2O.sub.3, Fe.sub.3O.sub.4, SnO.sub.2, Sb.sub.2O.sub.3, SiO.sub.2, Al.sub.2O.sub.3, MgF.sub.2, ZrO.sub.2, B.sub.2O.sub.3, Cr.sub.2O.sub.3, ZnO, CuO, NiO and mixtures thereof.

17. The process according to claim 16, wherein said flake-form support comprises natural mica, synthetic mica, SiO.sub.2 or Al.sub.2O.sub.3.

18. The process according to claim 16, wherein said flake-form support comprises Al.sub.2O.sub.3.

19. A process for modifying the optical properties of an effect pigment-containing coating, said process comprising: a) applying a coating (A) comprising at least one binder, at least one effect pigment, and one or more IR radiation-absorbent components to a substrate, b) optionally solidifying said coating (A), and c) irradiating areas of said coating (A) applied to said substrate using an IR laser, whereby solely said one or more IR radiation-absorbent components are partly or completely displaced and/or partly or completely oxidized and/or partly or completely bleached in said irradiated areas of said coating (A), and, in the irradiated areas, said at least one effect pigment which was previously covered by said one or more IR radiation-absorbent components are partly or completely uncovered due to the partial or complete removal, oxidizing, and/or bleaching of said one or more IR radiation-absorbent components by the laser irradiation.

20. The process according to claim 19, further comprising applying a protective layer (B) to said coating (A) after said irradiating, and then solidifying said coating (A) and said protective layer (B) simultaneously.

21. The process according to claim 19, wherein said one or more IR radiation-absorbent components are partly or completely displaced from the irradiated areas of the coating (A).

22. The process according to claim 19, wherein said one or more IR radiation-absorbent components are partly or completely bleached in the irradiated areas of the coating (A).

23. A coated substrate comprising a substrate and a coating having an optically visible pattern, wherein said coating comprises at least one binder, at least one effect pigment, and one or more IR radiation-absorbent components and wherein said optically visible pattern comprises areas of said coating where the one or more IR radiation-absorbent components are present and areas where the one or more IR radiation-absorbent components are not present.

24. The coated substrate according to claim 23, wherein said optically visible pattern is not tactile.

25. The coated substrate according to claim 23, wherein said substrate is a paper, cardboard, wallpaper, laminate, tissue material, wood, a polymer, a metal, a security printing product or a material which comprises constituents of a plurality of these substances, and where the substrate has optionally been electrostatically pretreated and/or provided with a primer layer and/or another anchoring layer.

26. The coated substrate according to claim 25, wherein said substrate is a polymeric film or a metal foil.

27. A coated substrate comprising a substrate and a coating having an optically visible pattern, wherein said coating comprises at least one binder, at least one effect pigment, and one or more IR radiation-absorbent components, wherein said optically visible pattern comprises areas of said coating where the one or more IR radiation-absorbent components are present and areas where the one or more IR radiation-absorbent components are not present, and wherein said optically visible pattern is obtainable by a process according to claim 1.

28. A method of providing a decorative element, functional element or security feature on a product, said method comprising: a) applying a coating (A) comprising at least one binder, at least one effect pigment and one or more IR radiation-absorbent components to a surface of said product, b) optionally solidifying said coating (A), and c) irradiating areas of said coating (A) applied to said product using an IR laser to form said decorative element, functional element or security feature, whereby solely said one or more IR radiation-absorbent components are partly or completely displaced and/or partly or completely oxidized and/or partly or completely bleached in said irradiated areas of said coating (A), and, in the irradiated areas, said at least one effect pigment which was previously covered by said one or more IR radiation-absorbent components are partly or completely uncovered due to the partial or complete removal, oxidizing, and/or bleaching of said one or more IR radiation-absorbent components by the laser irradiation, and d) applying a protective layer (B) to said coating (A) treated in b).

29. The process according to claim 28, wherein said one or more IR radiation-absorbent components are partly or completely displaced from the irradiated areas of the coating (A).

30. The process according to claim 28, wherein said one or more IR radiation-absorbent components are partly or completely bleached in the irradiated areas of the coating (A).

31. A product prepared by the method according to claim 28.

32. The product according to claim 31, wherein said coating (A) is applied to a substrate selected from paper, cardboard, a wallpaper, a laminate, a tissue material, wood, a metal, a polymer, a security printing product and a material which comprises constituents of a plurality of these substances, and where the substrate has optionally been electrostatically pretreated and/or provided with a primer layer and/or another anchoring layer.

33. A product according to claim 31, wherein said product is a decorative material or security product.

34. A process for modifying the optical properties of an effect pigment-containing coating, said process comprising: a) applying a coating (A) comprising a binder, at least one effect pigment and one or more IR radiation-absorbent components to a substrate, b) drying said coating (A), c) irradiating said coating (A) applied using an IR laser, whereby solely said one or more IR radiation-absorbent components are partly or completely displaced from irradiated areas of said coating (A) and/or partly or completely oxidized and/or partly or completely bleached in said irradiated areas of said coating (A), and d) optionally applying a protective layer (B) to said coating (A) irradiated in c).

35. A coated substrate comprising a substrate and a coating having an optically visible pattern, wherein said coating comprises at least one binder, at least one effect pigment and one or more IR radiation-absorbent components and wherein said optically visible pattern comprises areas of said coating where the one or more IR radiation-absorbent components are oxidized and/or bleached and areas where the one or more IR radiation-absorbent components are not oxidized and/or bleached.

36. A process for modifying the optical properties of an effect pigment-containing coating, said process comprising: irradiating a coating (A) comprising at least one binder, at least one effect pigment, and at least one IR radiation-absorbent component using an IR laser, where said at least one IR radiation-absorbent component is partly or completely displaced from irradiated areas of said coating (A) and/or partly or completely oxidized and/or partly or completely bleached in said irradiated areas of said coating (A), and where, in the irradiated areas, said at least one effect pigment which was previously covered by said at least one IR radiation-absorbent component is partly or completely uncovered due to the partial or complete removal, oxidizing, and/or bleaching of said at least one IR radiation-absorbent component by the laser irradiation, wherein said at least one binder of the coating is not carbonized by the laser irradiation, and said at least one effect pigment is not modified.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a lasered logo in a coating which comprises the effect pigment Xirallic® Crystal Silver (exposure angle: 75°, observation angle: 0°).

(2) FIG. 2 shows a lasered logo in a coating which comprises the effect pigment Xirallic® Crystal Silver (exposure angle: 45°, observation angle: 0°).

(3) FIG. 3 shows a lasered logo in a coating which comprises the effect pigment Xirallic® Crystal Silver (photograph in sunlight).

(4) FIG. 4 shows a lasered image in a coating which comprises the effect pigment Xirallic® Crystal Silver.

(5) FIG. 5 shows a photomicrograph of the transition from the lasered area (top right) to the unlasered area (bottom left) with full bleaching of the carbon black.

(6) FIG. 6 shows a photomicrograph of the transition from the lasered area (bottom half of the picture) to the unlasered area (top half of the picture) with displacement of the carbon black from the lasered stripes into the edge regions.

(7) FIG. 7 shows the measurement geometry on the BykMac instrument for determining the ΔL, ΔS.sub.i, ΔS.sub.a values.

(8) Without further elaboration, it is believed that one skilled in the art can, using the preceding description, utilize the present invention to its fullest extent. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way whatsoever.

(9) The preceding examples can be repeated with similar success by substituting the generically or specifically described reactants and/or operating conditions of this invention for those used in the preceding examples.

(10) From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications of the invention to adapt it to various usages and conditions.