Method for producing a coated tool by means of metallic coating of plastics, and a coated tool

Abstract

The invention relates to a method for producing a coated tool (1, 10, 100, 200) for use in printing methods, in particular flexographic printing, or in embossing methods, which method comprises the steps: a. providing an imaging layer (2, 20, 120, 220) made of a synthetic material, and b. applying a wear-protection layer (3, 30, 130, 230), the application being performed by means of a method for the metallic coating of plastics. The invention also relates to a coated tool (1, 10, 100, 200), produced by means of a method according to the invention, for use in printing or embossing methods, in particular a press tool such as an anilox roll, an anilox sleeve, a gravure form or an embossing die.

Description

[0001] Method for producing a coated tool by plastic metallization and a coated tool

[0002] The invention relates to a method for producing a coated tool by plastic metallization and to a coated tool produced by the method.

[0003] Printing and embossing processes utilize various tools, such as anilox rollers, printing or embossing dies. These can be provided in various shapes, such as round or flat, and used as cylinders, sleeves, or plates. These tools are often made of metal or ceramic to withstand the mechanical stresses of embossing or printing.

[0004] A disadvantage of these metal- or ceramic-based tools is their relatively high weight, which makes replacement, for example, only possible with considerable effort, and requires a correspondingly robust storage design. Therefore, tools based on a synthetic material are of interest, as they can significantly reduce weight. A method for producing plastic cylinders for printing is described, for example, in DE 690 12 605 T2.

[0005] However, the durability of printing or embossing tools made of synthetic materials has proven to be disadvantageous, as wear is higher than with tools made of metal or ceramic. Wear results in particular from the mechanical movement of a doctor blade and / or from contact between the embossing roller and the printing forme during printing, and from the mechanical movement between the embossing forme and the substrate to be embossed during embossing.

[0006] It is the object of the invention to further develop the method mentioned at the outset in such a way that it can provide a coated tool which has wear properties comparable to metal- or ceramic-based tools.

[0007] This object is achieved by a method having the features of claim 1 and a coated tool according to claim 18. Advantageous embodiments are the subject of the respective dependent claims. The method according to the invention for producing a coated tool comprises the following steps: a. Providing an imaging layer, for example an engraving layer or a laser layer made of a synthetic material, and b. Applying a wear-resistant layer.

[0008] The wear protection layer is applied using a plastic metallization process.

[0009] By applying a wear-resistant layer, the method according to the invention enables, in particular, the synthetic material of the imaging layer to be protected from wear and thus the durability of the tool can be increased.

[0010] Coated tools are understood here to mean, in particular, anilox roller tools, preferably for use in flexographic printing, as well as printing and embossing forms.

[0011] Plastic metallization is the coating of a material that is essentially plastic or other synthetic materials with a metal II layer or a material that exhibits metal-like properties. In particular, plastic metallization includes processes such as physical vapor deposition, thermal spraying, and plastic electroplating.

[0012] The wear-resistant layer is preferably applied by plasma coating, preferably by sputter deposition or thermal spraying, particularly preferably by physical vapor deposition. Plasma coating can be carried out as a low-temperature process by cooling the coated tool to a temperature that does not exceed 500°C, preferably 250°C, particularly preferably 180°C. The invention thus makes it possible to provide a suitable temperature, depending on the synthetic material, so that no damage to the imaging layer is caused.

[0013] The wear-resistant layer may comprise carbon and / or metal, thereby achieving increased resistance. The carbon is preferably an amorphous carbon, particularly preferably a diamond-like carbon (DLC). Amorphous carbons, in particular with a sp3 Hybridization levels of over 70% exhibit excellent hardness properties and can be applied as an amorphous carbon layer, for example, by physical vapor deposition. Furthermore, the wear-resistant layer can alternatively or additionally comprise silicon. The wear-resistant layer is preferably applied by plastic electroplating. Before applying the wear-resistant layer, a conductive layer can be provided by applying a conductive varnish to the imaging layer or by pickling and activating the imaging layer with metal nuclei, such as palladium.

[0014] The conductive ink can, for example, comprise graphite, copper, silver, or the like. Graphite, in particular, is both electrically conductive and chemically resistant, which means that a conductive ink containing graphite can be advantageous in terms of durability and wear properties. During plastic electroplating, a nickel and / or copper layer can be applied as a metal layer to the imaging layer. Preferably, at least one nickel layer is applied when using a conductive ink containing silver, and at least one copper layer is applied when using a conductive ink containing copper.

[0015] Furthermore, plastic electroplating can include the application of a chrome layer. This has the advantage of further increasing the wear resistance of the wear-resistant layer.

[0016] The wear-resistant layer applied by plastic metallization preferably has a total thickness of between 0.01 mm and 10 mm, preferably between 0.02 and 5 mm, and particularly preferably between 0.025 and 2 mm. The optional chromium layer is preferably thicker than the nickel and / or copper layer, and is particularly preferably at most twice as thick.

[0017] The synthetic material preferably comprises a rubber or plastic material, preferably an elastomer, coelastomer, polymer, or copolymer. By using synthetic materials as the base material, the invention enables lower weight, resistance to corrosion, and more cost-effective production compared to the use of known materials such as metal and ceramic. The synthetic material is particularly preferably fiber-reinforced, in particular with carbon fiber, so that the imaging layer has advantageous stiffness and strength values.

[0018] The method may further comprise providing a carrier layer to which the provided imaging layer is applied. The carrier layer preferably comprises metal, carbon fiber reinforced plastic, elastomer and / or plastic. The carrier layer may have different thicknesses, depending on whether the coated tool is designed as a plate, sleeve, or cylinder. For example, in a cylindrical embodiment, the carrier layer may be designed as a solid core, thus increasing the strength of the tool. In a design as a plate, the carrier layer may, for example, be very thin, but may be advantageous for attaching the plate compared to attaching it to the synthetic material of the imaging layer.

[0019] Preferably, the imaging layer is directly engraved by laser engraving, which allows for high shaping quality and simplifies the manufacturing process compared to the use of photopolymers. In particular, direct laser engraving enables depth- and / or area-variable structuring of the imaging layer.

[0020] The coated tool according to the invention is, for example, a printing tool such as an anilox roller or an embossing tool and is manufactured according to a method according to the invention. As a result, the invention enables the tool to be lightweight, since it is made of a synthetic material. On the other hand, the wear-resistant coating increases its durability.

[0021] The coated tool can be designed as a sleeve, cylinder, or plate, making it suitable for a wide range of printing and embossing processes.

[0022] Further details of the invention are explained with reference to the following figures.

[0023] Figure 1 shows a first exemplary embodiment of a coated, plate-shaped tool produced according to a method according to the invention;

[0024] Figure 2 shows a second exemplary embodiment of a coated, plate-shaped tool produced according to a method according to the invention;

[0025] Figure 3 shows an exemplary embodiment of a coated, sleeve-shaped tool produced according to a method according to the invention; and

[0026] Figure 3 shows an exemplary embodiment of a coated, cylindrical tool produced according to a method according to the invention.

[0027] Fig. 1 shows a coated tool 1 for use in printing or embossing processes, which is embodied here as a plate. The tool 1 comprises a carrier layer 6, an imaging layer 2, and a wear-resistant layer 3. The production of the coated tool 1 comprises the following steps: a. Providing the carrier layer 6; b. Providing the imaging layer 2 and applying the imaging layer 2 to the carrier layer 6; and c. Applying the wear-resistant layer 3.

[0028] The carrier layer 6 is made of metal here, but in further embodiments, it may alternatively or additionally comprise carbon fiber-reinforced plastic, elastomer, and / or plastic. The synthetic material of the imaging layer 2 here is a carbon fiber-reinforced elastomer. In further embodiments not shown, the synthetic material may alternatively or additionally comprise a coelastomer, polymer, or copolymer.

[0029] The wear-resistant layer 3 is applied using a plastic metallization process, here by plasma coating, in particular by physical vapor deposition. Cooling measures are used to keep the coated tool at a temperature not exceeding 250°C. In further, not-shown embodiments, other plasma coating processes can be used, such as sputter deposition or thermal spraying. The cooling measures can be adjusted so that, depending on the temperature tolerance of the synthetic tool 1, a maximum temperature is not exceeded, thus preventing damage to the synthetic material.

[0030] The wear protection layer 3 here comprises an amorphous carbon, in particular a diamond-like carbon. Due to the advantageous hardness properties of the diamond-like carbon, a wear protection layer of less than 0.5 mm is sufficient to provide adequate protection against wear. In further embodiments not shown, the wear protection layer can additionally or alternatively comprise a metal and / or silicon.

[0031] The imaging layer 2 is directly engraved by laser engraving. This allows for high printing or embossing quality with advantageous production of the printing or embossing form. In particular, laser engraving can provide engraving with good resolution and short production times.

[0032] In a modification of the coated tool shown in Fig. 1, the coated tool 10 shown in Fig. 2 is applied with the wear-resistant layer 30 by plastic electroplating. For this purpose, a conductive ink is applied to the imaging layer 20 before the wear-resistant layer 30 is applied. The conductive ink here comprises graphite, so that the application of the conductive ink provides a conductive layer 40. In further

[0033] In some embodiments, conductive ink may additionally or alternatively comprise copper or silver.

[0034] After applying the conductive layer 40, a metal layer 45 made of nickel is applied as part of the wear-resistant layer 30 using a galvanic process. In further embodiments, copper can also be applied as the metal layer 45 additionally or alternatively. Here, the wear-resistant layer 30 additionally comprises a chromium layer 50 applied during galvanization to further increase the durability of the coated tool 10.

[0035] Fig. 3 shows a tool 1 manufactured as in Fig. 1, wherein the coated tool 100 in Fig. 3 is designed as a sleeve. Thus, the coated tool 100 can be advantageously retrofitted for printing or embossing processes, for example, by being mounted as an exchangeable sleeve on an anilox roller, a printing or embossing cylinder.

[0036] In a modification of the tool 10 shown in Fig. 2, the coated tool 200 in Fig. 4 is designed as a cylinder. Furthermore, the conductive layer 240 is provided by pickling and activating the imaging layer 220 with metal nuclei. The surface of the imaging layer 220 is roughened by pickling with an oxidative metal salt solution and then activated with palladium, so that a conductive layer 240 of 0.3 to 0.4 pm copper can be formed by chemical metallization. Alternatively, a conductive layer 240 of nickel can also be formed in this way. As in the exemplary embodiment shown in Fig. 2, the wear-resistant layer 230 comprising a metal layer 245 made of nickel and / or copper 240 and a chromium layer 250 is then applied by electroplating.

[0037] The features of the invention disclosed in the above description, in the drawings and in the claims may be essential for the realization of the invention both individually and in any combination.

[0038] List of reference symbols.

[0039] 1, 10, 100, 200 Coated tool

[0040] 2, 20, 120, 220 imaging layer, in particular engraving layer or laser layer

[0041] 3, 30, 130, 230 wear protection layer

[0042] 40, 240 Conductive layer

[0043] 45, 245 metal layer

[0044] 50, 250 chrome layer

[0045] 6, 60, 160, 260 carrier layer

Claims

Claims:

1. A method for producing a coated tool (1, 10, 100, 200) for use in printing processes, in particular gravure or flexographic printing, or in embossing processes, comprising the steps of: a. providing an imaging layer (2, 20, 120, 220), for example an engraving layer or a laser layer, made of a synthetic material and b. applying a wear-resistant layer (3, 30, 130, 230), the application being carried out by a plastic metallization process.

2. Method according to claim 1, wherein the application of the wear protection layer (3, 30, 130, 230) is carried out by plasma coating.

3. The method according to claim 2, wherein the plasma coating is carried out by physical vapor deposition, for example sputter deposition, or thermal spraying.

4. The method according to claim 2 or 3, wherein the plasma coating is carried out as a low-temperature process by keeping the coated tool (1, 10, 100, 200) by cooling measures at a temperature which does not exceed 500°C, preferably 250°C, particularly preferably 180°C.

5. Method according to one of claims 2 to 4, wherein the wear protection layer (3, 30, 130, 230) comprises carbon and / or metal.

6. The method according to claim 5, wherein the carbon is an amorphous carbon, in particular a diamond-like carbon.

7. The method according to claim 5 or 6, wherein the wear protection layer (3, 30, 130, 230) additionally comprises silicon.

8. Method according to claim 1, wherein the application of the wear protection layer (3, 30, 130, 230) is carried out by galvanizing, for example plastic galvanizing.

9. Method according to claim 8, wherein before applying the wear protection layer (3, 30, 130, 230) by applying a conductive varnish to the laser layer (2, 20, 120, 220) or by pickling and activating with metal nuclei, such as palladium, the Laser layer (2, 20, 120, 220) a conductive layer (40, 240) is provided.

10. The method according to claim 9, wherein the conductive ink comprises graphite, copper, silver, shielding ink, silver-coated copper, nickel or other conductive metals.

11. Method according to one of claims 8 to 10, wherein a nickel and / or copper layer (45, 245) is applied to the imaging layer (2, 20, 120, 220) during plastic electroplating.

12. Method according to one of the preceding claims, wherein the synthetic material of the imaging layer (2, 20, 120, 220) is a rubber or plastic material, for example an elastomer, coelastomer, polymer or copolymer.

13. The method according to claim 12, wherein the synthetic material is fiber-reinforced, in particular with carbon fiber.

14. The method according to any one of claims 8 to 13, wherein the plastic electroplating comprises applying a chromium layer (50, 250).

15. Method according to one of the preceding claims, in which, before the provision of the imaging layer (2, 20, 120, 220), a carrier layer (6, 60, 160, 260) is provided, to which the provided imaging layer (2, 20, 120, 220) is applied.

16. The method according to claim 15, wherein the carrier layer (6, 60, 160, 260) comprises metal, carbon fiber reinforced plastic, elastomer and / or plastic.

17. Method according to one of the preceding claims, in which the imaging layer (2, 20, 120, 220) is produced by laser engraving, electromechanical engraving or milling.

18. Coated tool (1, 10, 100, 200) for use in printing or embossing processes, in particular a printing tool such as an anilox roller, an anilox sleeve, an intaglio printing form or an embossing form, produced by a process according to claims 1 to 17.

19. Coated tool (1, 10, 100, 200) according to claim 18, which is designed as a sleeve, cylinder or plate.

Images