Composite panel with barrier layer and method for manufacturing a letterpress plate

Abstract

A composite panel for use in the manufacture of a letterpress plate has a carrier layer, with at least one photo layer which can be structured via electromagnetic radiation in a wavelength range. The photo layer is arranged on the carrier layer. The task of proposing a composite panel use in the manufacture of a letterpress plate is achieved by the fact that a barrier layer is provided. The barrier layer is arranged on the side of the photo layer opposite to the carrier layer. The barrier layer is essentially transparent in the wavelength range in which the photo layer can be structured. The present disclosure concerns a process for manufacturing a letterpress plate using at least one composite panel and a process for manufacturing a composite plate in accordance with the invention. The invention concerns the use of a composite material in a composite panel for a letterpress plate.

Claims

1. A method for manufacturing a letterpress plate using at least one composite panel, the method comprising the following steps: providing a carrier layer; arranging at least one photo layer on the carrier layer, in which the at least one photo layer is structurable via electromagnetic radiation in a wavelength range; arranging a barrier layer on a side of the at least one photo layer opposite to the carrier layer; applying at least one mask material to the composite panel by lamination; selectively structuring the at least one mask material; selectively exposing the at least one mask material; selectively removing the at least one mask material; influencing the solubility of the at least one mask material by selectively exposing the at least one mask material to a visible range; structuring the at least one mask material using a solution; selectively exposing the at least one photo layer at least in the wavelength range; and removing the selectively exposed at least one photo layer, wherein the barrier layer has a layer thickness of at most 20 m, wherein the barrier layer is essentially transparent in the wavelength range, in which the at least one photo layer is structurable via electromagnetic radiation, and wherein the at least one mask material comprises diazo compounds.

2. The method according to claim 1, further comprising the step of applying the at least one mask material as a layer.

3. The method according to claim 1, further comprising the step of fastening the at least one composite panel in sections on a letterpress carrier.

4. The method according to claim 3, wherein portions on the letterpress carrier are configured to remain free during the fastening of the at least one composite panel and are covered with at least one compensating layer prior to applying the at least one mask material.

5. A method of manufacturing of a composite panel for use in the manufacture of a letterpress plate, comprising the steps of: applying a carrier layer, at least one photo layer, a barrier layer and at least one mask material to one another; arranging the at least one photo layer on the carrier layer, in which the at least one photo layer is structurable via electromagnetic radiation in a wavelength range; arranging the barrier layer on the side of the at least one photo layer opposite to the carrier layer; and laminating the at least one mask material onto the barrier layer, wherein the barrier layer is essentially transparent in the wavelength range in which the at least one photo layer is structurable, wherein the at least one mask material comprises diazo compounds and has a solubility that can be influenced by selective exposure in the visible range wherein applying the at least one mask material involves laminating, and wherein the barrier layer is applied together with the at least one mask material to the side of the at least one photo layer opposite to the carrier layer.

6. The method according to claim 5, wherein the at least one mask material is provided with the barrier layer as a composite material and the composite material is applied by lamination.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) For further information on the embodiment of the composite panel, the processes and its use, refer to the following description of examples of embodiment on the basis of the drawing. In the drawings is shown:

(2) FIG. 1 a composite panel,

(3) FIG. 2 an embodiment example of a composite panel,

(4) FIG. 3 another embodiment example of a composite panel,

(5) FIG. 4 the embodiment example from FIG. 3 with a selective exposure of the photo layer,

(6) FIG. 5a,b two embodiments of a letterpress forms made from the composite panel and

(7) FIG. 6 another embodiment example of a composite panel on a letterpress carrier.

DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a composite panel 2. The composite panel 2 has a carrier layer 4 and at least one photo layer 6, in which the photo layer 6 is arranged on the carrier layer 4. The photo layer 6 can be arranged directly on the carrier layer 4 or optionally at least one intermediate layer is provided, for example an additional adhesion layer (not shown).

(9) The photo layer 6 can be structured via electromagnetic radiation in a wavelength range. For example, photo layer 6 is based on photopolymers, in which the photo layer is designed to change certain properties of the photo layer, in particular the solubility and/or the curing properties, in the ultraviolet and/or violet wavelength range, i.e. for example within a range from 100 nm to 380 nm or within a range from 380 nm to 425 nm.

(10) In particular, the mechanical properties of the composite panel 2 can be adjusted via the design of the carrier layer 4. For example, carrier layer 4 is based on polyethylene terephthalate and/or has a thickness of 0.05 mm to 0.2 mm, in particular 0.1 mm to 0.15 mm. The total thickness of composite panel 2, for example, is from 0.5 mm to 3.0 mm. In particular, composite panel 2 is designed for the production of a flexographic printing plate.

(11) A barrier layer 8 is provided on the side of the photo layer 6 opposite to the carrier layer 4, in which the barrier layer 8 has a layer thickness d of at most 100 m, preferably at most 20 m, in particular of at most 10 m or of at most 5 m and in which the barrier layer 8 is substantially transparent in the wavelength range in which the photo layer 4 can be structured. For example, the barrier layer 8 is essentially transparent in the ultraviolet and/or violet wavelength range, i.e. for example within a range of 100 nm to 380 nm or within a range of 380 nm to 425 nm, i.e. it allows a large part of the radiation intensity to pass through in this wavelength range. In particular, at least 50%, preferably at least 75%, further preferably at least 95% of the incident intensity can penetrate the barrier layer 8.

(12) The barrier layer 8 is arranged directly on the photo layer 6 and is thus in contact with the photo layer 6. The barrier layer 8 provides a diffusion barrier for the photo layer 6 against the surrounding atmosphere, while at the same time an exposure of the photo layer 6 through the barrier layer 8 is possible due to the low layer thickness d and the transparent properties of the barrier layer 8. The barrier layer 8, for example, is based on at least one polymer. The barrier layer 8 includes or consists, for example, of polyethylene terephthalate.

(13) It has been found that the quality and resolution of the letterpress plate made from the composite panel 2 can be improved via the barrier layer 8. The barrier layer 8 remains on the photo layer 6 when the photo layer 6 is exposed, as also explained in connection with the following figures. Especially due to the small layer thickness of less than 20 m, especially less than 10 m or 5 m, refraction effects at the barrier layer 8 are curbed, so that only little or no loss of quality is caused by the barrier layer 8. At the same time, the influence of the surrounding atmosphere through the barrier layer 8 is significantly reduced, which leads to a significant increase in the quality of the structured surface of the photo layer 6.

(14) In the following, embodiment examples of the design of the composite panel 2 are explained using FIGS. 2 and 3, and at the same time an embodiment example of the of the process in accordance with the invention is described. For the sake of clarity, the same reference signs as in FIG. 1 are used in the following figures for corresponding elements.

(15) FIG. 2 shows an embodiment example of a composite panel 2 in which at least one mask material 10 is arranged on the barrier layer 8. The mask material 10 is formed as a layer and covers the entire surface of the photo layer. The mask material is laminated. The mask material 10 can be structured, for example by removing the mask material 10 section by section and/or changing the properties section by section.

(16) In particular, mask material 10 is designed to change its properties under the influence of electromagnetic radiation. The advantage of the composite panel 2 is that the photo layer 6 is shielded from the surrounding atmosphere by the barrier layer 8 during exposure. The exposure of the mask material 10 thus only negligibly affects the photo layer.

(17) The mask material includes diazo compounds, which can be selectively exposed and removed as known from the state of the art. For example, corresponding compounds with a wavelength of 405 nm can be exposed and/or dissolved with a solution containing ammonia and/or water. In the use of a solution for structuring the mask material 10, the barrier layer 8 advantageously acts to contain the action of the solution, for example a solution comprising ammonia, on the photo layer 6.

(18) FIG. 3 shows another embodiment example of a composite panel 2, in which the mask material 10 has a structure for selectively exposing the photo layer 6. The structure is shown here in the form of recesses between individual sections of the mask material 10.

(19) The structure of the mask material 10 can, for example, be achieved by selectively removing the mask material 10 as described above for FIG. 2. The mask material 10 is based on diazo compounds and is structured by exposure.

(20) Alternatively or cumulatively, the mask material 10 can also be structured by selectively applying the mask material 10. For example, mask material 10 is selectively printed on and is based on ink and/or wax, preferably a combination of UV-curable ink and wax.

(21) FIG. 4 now shows the embodiment example of the composite panel 2 from FIG. 3 with a selective exposure of the photo layer 6, in which electromagnetic radiation 12 acts on the composite panel 2 at least in the wavelength range in which the photo layer 6 can be structured. The barrier layer 8 is essentially transparent to the radiation 12, so that the radiation 12 acts selectively on sections 6 of the photo layer 6 due to the coverage by the mask material 10. The advantage of the composite panel 2 is that the photo layer 6 is shielded from the surrounding atmosphere by the barrier layer 8 and at the same time only slight refractive effects occur at the barrier layer 8. The exposure of the photo layer 6 can be done with high resolution and high quality.

(22) The selectively exposed photo layer 6 can be selectively removed. In the case of photopolymers, for example, the usual process steps for the development and selective removal of photo layer 6 can be carried out. In particular, the mask material 10 and/or the barrier layer 8 are removed before or after the treatment.

(23) FIG. 5a, b shows two embodiments of a letterpress form made of composite panel 2, which are designed as flexographic printing forms 14. The flexographic printing form 14 shown in FIG. 5a, for example, is derived from the selectively exposed composite panel 2 shown in FIG. 4, in which the photo layer 6 reacts particularly positively to an exposure. For example, the solubility of the exposed sections 6 is increased, which results in recesses in the corresponding areas when they are detached.

(24) FIG. 5b shows a flexographic printing plate 14 with a negative reaction of the photo layer 6. For example, the solubility of the exposed sections 6 is reduced, resulting in recesses in the unexposed sections when they are detached.

(25) FIG. 6 shows another example of a composite panel 2 on a letterpress carrier. Above an bench 16 an exposure unit 18 is provided, which is sketched as a linear light source in the example shown, which can be moved relative to the bench 16 for complete exposure.

(26) Composite panels 2 are attached to the flexographic printing carrier 20. The mask material 10 can be applied by printing, for example. In FIG. 6, however, a leveling layer 22 is provided in the free sections on the flexographic printing support 20, so that mask material 10 can be applied to the composite panels 2 and the leveling layer 22. The arrangement of the leveling layer 22 ensures that the mask material 10 does not sag or cause waves in the areas covered by the leveling layer 22. A particularly precise alignment of the composite panels 2 can be ensured in a particularly simple manner, in particular by using a register 24.

(27) As known from the state of the art, the at least partially unexposed composite plates 2 are preferably cut using a cutting plotter. It is also advisable to cut the leveling layer 22 with the aid of a cutting plotter known per se. Various cost-effective materials can be used as leveling layer 22. Preferably, these have a thickness that essentially matches that of the composite panels 2. Materials such as cardboard or elastic materials such as rubber panels or polymer panels can be considered.

(28) In an embodiment example of the method of manufacturing a composite panel, a carrier layer, at least one photo layer, one barrier layer and at least one mask material are applied to one another.

(29) The barrier layer is applied together with the mask material on the side of the photo layer opposite to the carrier layer. For this purpose, a composite material comprising mask material and barrier layer is first provided, in which the mask material and the barrier layer are bonded to one another by adhesion and/or by a material bonding. For example, the mask material is applied to the barrier layer by lamination.

(30) The composite material comprising mask material and barrier layer is used to provide a composite panel for making a letterpress form. The composite material is applied to a carrier layer and a photo layer. The application of the composite material involves laminating. In particular, a further composite material comprising carrier layer and photo layer is provided, to which the composite material comprising mask material and barrier layer is applied, in particular by lamination.

(31) By using the composite material comprising mask material and barrier layer, a particularly economical process for manufacturing the composite panel can be carried out. The need for an additional carrier film or release film for applying the mask material is eliminated with the barrier layer, which at the same time provides a diffusion barrier layer for the subsequent structuring of the composite panel to produce a letterpress forms.