Press plates for creating deep structures

Abstract

The invention relates to a press plate for creating deep structures in board-like products, in particular in wood-based panels or laminates made of resin-coated paper, which consists of a metallic base body (1) in which provided recesses (4) are inserted strip-shaped and / or frame-shaped ribs (2, 3) having a higher thermal conductivity than the base body (1).

Description

Technical Field

[0001] The invention relates to a press board for creating deep structures in board-like products, for example in boards of wood material or laminates made of resin-coated paper (kraft paper). Background Art

[0002] Such a pressure plate can be found, for example, in DE 10 2014 010 747 B4.

[0003] In many branches of industry, structured press plates are used as press molds to produce structured surfaces. Press plates are usually steel plates with a thickness of several millimeters (mostly 5 mm), which are chrome-plated and polished. In the wood material industry, such press plates are used in so-called short-cycle presses. In such short-cycle presses, synthetic resin-impregnated decorative paper is pressed onto a wood material board under pressure and temperature. During the pressing process, the synthetic resin is melted and cross-linked, partially penetrating into the wood material board, thereby establishing a good anchoring of the synthetic resin-impregnated paper on the wood material board. The press plate disclosed in DE 102014010747 B4 can be used to emboss onto the top surface of a wood material board in an infiltration manner. However, it is not possible to emboss a structure into a wood material board.

[0004] It is also known to laminate synthetic resin impregnated decorative paper with phenolic resin impregnated kraft paper. The laminate thus produced is then laminated to a carrier board and used as a worktop or partition wall or the like.

[0005] EP 2127901 B1 discloses a method for producing floor panels, for which a short-cycle press is used, wherein the press plate has two closely juxtaposed ribs and additional separately arranged ribs in the region with a low-pressure zone for the subsequent further processing of the floor panel, for simulating the joint filling line. The region with two ribs or the separately arranged stamp is repeated at desired intervals. The embossed recesses can have a variety of different shapes. After embossing, the board can be divided into individual strips or panels. However, these generally have to be further processed into a plurality of continuous parts, so that only narrow, small-area high-pressure zones are required to emboss the continuous parts. In this case, the entire continuous strip or panel surface is referred to as the low-pressure zone.

[0006] The structures on the press plate are usually made by etching. In a complex process, an acid-resistant paint is printed onto the steel blank, which corresponds to the later structure in the printed image. In the subsequent etching process, the glass material is removed in the unpainted areas. There is no paint in these areas. The problem here is that it is not possible to obtain any etching depth by a single etching process. This means that a large number of etching cycles must be experienced for deep structures. This results in a time-consuming and expensive manufacturing process as described in EP2186650B1.

[0007] Above a certain structure depth, etching techniques can no longer be used, because the above-mentioned paint can no longer be applied precisely to deeper structures. Typically, the deep structures created by etching techniques are around 200 μm.

[0008] Press plates used for pressing furniture impregnations can withstand 70,000 to 100,000 presses without noticeable wear. When using impregnations containing corundum, the number of possible presses is reduced by a factor of two to a factor of three. If a deep structure is still required, the number of presses before refinishing can be halved again. This not only leads to higher costs, but also to an increase in the demand for the board material.

[0009] EP 2991293 B1 discloses a short cycle press in which the edges of the press plates are provided with frame-like protrusions to prevent the molten paper stock resin from squeezing out at the edges of the press plates during pressing, thereby significantly reducing the tendency to wear. During pressing, the resin flows and, without the protrusions, the molten resin squeezes out to the sides. If the resin-impregnated paper also contains hard material, such as corundum, the extension of the press plates during pressing can lead to relative movement between the corundum particles and the press plates, which can lead to increased wear.

[0010] DE 102010031421 A1 discloses a press whose pressing plate has outwardly facing ribs. These ribs are integrally formed with the pressing plate and are used to guide the pressing plate in a labyrinth plate.

[0011] DE 102012004375 U1 discloses a material sheet, in which raised and recessed areas are formed in a structured surface. The surface is embossed by a press plate or an endless belt, and has a first glossiness over the entire surface, and in a further working step, further different glossiness is obtained in a plurality of selected areas. The glossiness is produced by a metal coating or by mechanical and / or chemical post-treatment.

[0012] DE 102011051266 A1 discloses a pressed body for producing laminates and a method for producing a pressed body. The structured surface area of ​​the pressed body has elevations formed by a non-visible material, in particular ink. The elevations can be hardened as required. Summary of the invention

[0013] In view of this, the object of the invention is to produce a press plate with which very deep structures can be embossed, in particular in wood material panels to be coated with a thermosetting decorative impregnation. This makes complex etching processes no longer necessary. A simple and feasible press plate production concept is provided for special applications.

[0014] To achieve the above-mentioned object, the pressure plate is characterized by a metal base body, in which provided recesses are inserted strip-shaped and / or frame-shaped ribs, which have a higher thermal conductivity than the base body.

[0015] This design is particularly useful for embossing corundum-containing impregnations with deep structures and / or special surfaces, where the press plate needs to be reconditioned relatively frequently due to wear. The areas that are subject to particularly high stress are those where the strip is embossed into the plate. These areas can be replaced if they are not made integrally of the press plate but are formed by scarfing ribs that can be connected to the press plate.

[0016] The ribs can be connected to the base body in a form-fitting and / or material-fitting manner. In particular, when reconditioning worn-out press plates, it is advantageous that the connection of the embedded ribs is detachable. Areas with deep structures are subject to heavy wear, especially when processing corundum-containing resins or cladding impregnations. This means that the stainless steel plates that are usually used must be reconditioned within a relatively short period of time.

[0017] By adopting this profile design in the base body, the pressure plate can be quickly remade, because the ribs can be repeatedly removed by milling and replaced with new elements. In particular, the adhesively bonded or welded ribs can be removed from the pressure plate by sophisticated methods. Only the area where the strips are located needs to be heated above the melting point of the solder or adhesive. The pressure plate is used at temperatures between 190°C and 220°C, so the welding and bonding must have a thermal stability of well above 220°C. In the case of brazing, hard soldering with silver solder or brass solder must be used. In the case of bonding, high-temperature epoxy glues with a thermal stability of more than 250°C should be used. Depending on the state of wear, the ribs can be repaired or replaced with new ones.

[0018] The ribs have a higher thermal conductivity than the base body, so that the areas to be deformed in the wood-based panels or laminates are heated and elasticized more quickly. Since overheating of the board-shaped product is avoided, the embossing process can be designed to be significantly more material-efficient. If deep structures are embossed into the wood-based panels, overheating of the wood material is avoided and the glue provided for the wood fibers or sawdust is prevented from drying up or being damaged.

[0019] In order to insert the ribs into the base body, preferably a groove-shaped recess is milled out of the base body, into which recess the ribs can be glued, soldered or welded.

[0020] The ribs can consist of a steel alloy, an aluminum alloy, a brass alloy or a copper alloy. Pure metals can also be used, or alloy components can be present within a certain percentage range. In particular, copper can be used as the pure metal.

[0021] The base body and the ribs are preferably chrome-plated, and the rib edges facing away from the base body are particularly preferably rounded. The ribs can have a height of 0.2 mm to 5 mm. The height is preferably 1 mm to 3 mm, in particular 2 mm.

[0022] Both the top side of the ribs and the top side of the base body can have a structured section, by means of which, for example, a structure corresponding to the decoration can be impressed into the surface. In the case of wooden decorations, the structured section then represents a homogeneous wood grain to create so-called "synchronous holes".

[0023] If a special optical design is required for the finished top surface, the structured portion of the base can be different from the structured portion of the ribs. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings.

[0025] Figure 1 A perspective view showing a first pressing plate designed according to the present invention;

[0026] Figure 2 Shown along Figure 1 Sectional view taken along the midline I II I;

[0027] Figure 3 A perspective view showing a second pressure plate designed according to the present invention;

[0028] Figure 4 A partial schematic diagram showing the ribs inserted into the pressure plate. DETAILED DESCRIPTION

[0029] The pressure plate consists of a base body 1, which is, for example, a steel plate with a thickness of 5 mm. In this steel plate, recesses 4 are introduced which are spaced parallel to one another and can be produced by etching or milling. Instead of the groove-shaped recesses 4, notches (openings) can also be provided, which do not have to extend over the entire width of the base body 1. Strip-shaped ribs 2 (see Figure 1 ) or frame rib 3 (see Figure 3 ). The ribs 2, 3 consist of a material with a higher thermal conductivity than the material of the base body 1. They are preferably made of an aluminum alloy, a brass alloy or a copper alloy. Steel alloys can also be used. The ribs 2 are connected to the base body 1 in a material-fitting manner, for example by welding or brazing to the base body 1. The ribs 2 can also be bonded into the recess 4 or the notch. The base body 1 has a structured part 1.2 on the top surface 1.1, with the help of which a structure matching the decoration of the wood material board or laminate can be embossed into the top surface of the board-shaped product. The top side 2.2 or 3.2 of the ribs 2, 3 can also be provided with a structured part 2.3, 3.3. The structured part 2.3, 3.3 of the ribs 2, 3 can be different from the structured part 1.2 of the base body 1.

[0030] The edges 2.1, 3.1 of the ribs 2, 3 facing away from the base body 1 can be rounded in order to simplify the embossing of the structure. Figure 4As shown, the transition 2.4 from the rib 2 to the pressure plate 1 can be rounded, so that there is no height difference in the transition area from the pressure plate 1 to the rib 2. Such a rounded portion can also be provided on the frame 3 (not shown).

[0031] The width of the upper area 2.5 of the rib 2 is variable. This width depends on the width of the desired impression in the product. This width is determined by the sawing that separates the large-format sheet into individual panels. The inclined side 2.6 of the rib 2 is reproduced on the product.

[0032] The pressure plate designed according to the present invention works as follows:

[0033] Embodiment 1:

[0034] In a smooth chrome-plated laboratory press plate (size: 650 mm×500 mm) as the base body 1, two recesses 4 with a width of more than 20 mm and a depth of less than 1 mm were first milled out at a distance of 200 mm, wherein two chrome-plated metal strips were used as pressure ribs 2 and were bonded to the steel laboratory press plate with the aid of a high-temperature-stable cyanoacrylate. The ribs 2, 3 were 2 cm wide and protruded 1 mm above the top side 1 of the press plate. These ribs were rounded on one side in the edge region 2.1. They were bonded to the base body 1 with the side with non-rounded edges. After the adhesive had cured, the press plate was installed as a top plate in a laboratory press. The HDF board (8 mm, green density 850 kg / m 3) was then covered with melamine resin-impregnated decorative paper on the top side and with a resist impregnation on the bottom side and pressed according to the following press parameters. After cooling, the indentation depth of the two strip-shaped recesses on the top side of the HDF board was determined.

[0035]

[0036] As can be seen from the table, significantly better deformation results can be achieved with metals having higher thermal conductivity. This means that when using metals having better thermal conductivity, more moderate pressing parameters can be used or lower strength adhesive ribs 2, 3 to achieve the same deformation results.

[0037] Embodiment 2:

[0038] In a non-chrome-plated laboratory press plate (format: 650 mm×500 mm×5 mm) with a wooden structure as the base 1, a frame 3 with the outer dimensions of 350 mm×350 mm×1 mm and a width of 20 mm was milled out in the middle. Subsequently, a steel-aluminum frame 3 (whose format is adapted to the recess 4 and has a height of 2 mm) was glued into the recess with the aid of a high-temperature-stable cyanoacrylate. The frame 3 was rounded in the lower edge region 3.4 so that after the gluing, no height difference was produced in the transition between the press plate and the frame 3. After the adhesive had cured, the press plate was installed in the laboratory press as a top plate. The HDF board (8 mm, green density 850 kg / m 3) was then covered on the top side with a melamine resin-impregnated decorative paper and on the bottom side with a resist impregnation and pressed according to the following press parameters. After cooling, the press depth of the two frame-shaped recesses on the top side of the HDF board was determined.

[0039]

[0040] As a comparison between Example 1 and Example 2 shows, using a slightly thicker aluminum strip inserted into the press plate again better results are obtained.

[0041] Embodiment 3:

[0042] In a non-chrome-plated laboratory press plate (size: 650 mm×500 mm×5 mm) with a wooden structure as base 1, a frame 3 with the outer dimensions of 350 mm×350 mm×1 mm and a width of 20 mm is milled out in the middle. Subsequently, a galvanized aluminum frame 3 (whose size fits the recess 4 and has a height of 2 mm) is inserted into the recess and welded to the press plate. The frame 3 is rounded in the upper edge area 3.1 so that after insertion, no height difference is generated in the transition between the press plate and the frame 3. The press plate is then chrome-plated. It is then installed as a top plate in the laboratory press. The HDF board (8 mm, green density 850 kg / m 3) is then covered on the top side with melamine resin-impregnated decorative paper and on the bottom side with a resist impregnation and pressed according to the following press parameters.

[0043] After cooling, the depth of the frame-shaped recess 4 on the top surface of the HDF board is determined.

[0044]

[0045] As a comparison between Example 2 and Example 3 shows, the bonding or welding strips made of aluminum do not lead to any significant differences in the depth of the structure.

[0046] If desired, glued or bonded ribs 2, 3 can be used, wherein the gluing process should be carried out before chrome plating. Of course, ribs 2, frames 3 or other geometric shapes that simulate, for example, inlays should be inserted into the milled steel sheet and brazed or connected by "arc welding". In this way, so-called "registered stamped" structures can be created, which would otherwise be difficult or costly to produce.

[0047] The press plate with the ribs 2 or frames 3 used can then be chrome-plated as a whole, if necessary, the metal ribs 2, metal frames 3, etc. to be used can first be prepared by pretreatment (e.g. galvanizing, anodizing). As high thermal conductivity metals, aluminum, brass and copper are suitable, of which copper is more suitable because its thermal expansion is comparable to that of steel.

[0048] Depending on the requirements, the required ribs 2 and / or frames 3 can already be taken into account during the production of the pressure plate. For example, when the pressure plate is structured (etched), the structuring can be omitted at the locations where the milled ribs 2 and / or frames 3 are to be located later. They can then be inserted after structuring and milling. This has the advantage that the structure of the pressure plate can be matched to the structure of the ribs / frames 2, 3. Depending on the height of the pressure plate, the ribs 2, 3 can have a height of more than 0.2 mm to 5 mm. Of course, ribs 2, frames 3 or other geometries can also be created by 3D printing of the pressure plate.

[0049] Such a pressboard can be used in particular for special products. It can be, for example, a board for producing laminate flooring, which should have a so-called press joint in the connection area or a specified seam for floor tile decoration. Furthermore, the ribs 2, frames 3 etc. used can of course also have a structured part that is different from the rest of the pressboard. This can, for example, have a wooden structure, while the embedded profiles can be unstructured.

[0050] Reference numerals list

[0051] 1 base / pressing plate

[0052] 1.1 Top surface

[0053] 1.2 Structural part

[0054] 2 ribs / frame

[0055] 2.1 Edge / marginal area

[0056] 2.2 Top surface

[0057] 2.3 Structural part

[0058] 2.4 Transition

[0059] 2.5 Region

[0060] 2.6 Side

[0061] 3 ribs / frame

[0062] 3.1 Edge / marginal area

[0063] 3.2 Top surface

[0064] 3.3 Structural part

[0065] 4 recess.

Claims

1. A press plate for creating a deep structure, which consists of a metallic base body (1), in which provided recesses (4) are inserted strip-shaped and / or frame-shaped ribs (2, 3), said ribs (2, 3) having a higher thermal conductivity than the base body (1); The top surface (1.1) of the base body (1) has a structured portion (1.2), and the ribs (2, 3) are unstructured; The transition part (2.4) from the ribs (2, 3) to the base body (1) is circular; The pressboard is used for the production of products of wood material boards or laminates made of resin-coated paper.

2. The pressing plate according to claim 1, characterized in that The ribs (2, 3) are connected to the basic body (1) in a materially bonded manner.

3. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) are connected to the base body (1) in a form-fitting manner.

4. The pressing plate according to claim 1 or 2, characterized in that: The base body (1) and the ribs (2, 3) are chrome-plated.

5. The pressing plate according to claim 1 or 2, characterized in that: The edges (2.1, 3.1) of the ribs (2, 3) facing away from the base body (1) are rounded.

6. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) consist of a steel alloy.

7. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) are made of aluminum alloy.

8. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) are made of copper alloy.

9. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) are made of a brass alloy.

10. The pressing plate according to claim 1 or 2, characterized in that: The pressure plate is chrome plated.

11. The pressing plate according to claim 1, characterized in that The top surface (2.2, 3.2) of the rib (2, 3) has a structured portion (2.3, 3.3).

12. The pressing plate according to claim 11, characterized in that The structured portion (1.2) of the base body (1) is different from the structured portion (2.3, 3.3) of the ribs (2, 3).

13. The pressing plate according to claim 1 or 2, characterized in that: The height (H) of the ribs (2, 3) is at most 5 mm.

14. The pressing plate according to claim 2, characterized in that The ribs (2, 3) are welded or bonded to the base body (1).

15. The pressing plate according to claim 1 or 2, characterized in that: The ribs (2, 3) are created by 3D printing.

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