阅读说明：本技术 用于在液压的单层或多层热压机中使用的压垫以及压垫压板单元和压板加热板单元 (Pressure pad for use in a hydraulic single-layer or multi-layer hot press, and pressure pad press plate unit and press plate heating plate unit ) 是由 R.埃斯佩 于 2020-02-18 设计创作，主要内容包括：本发明涉及一种用于在液压的单层或多层热压机中使用的压垫(1、1′),所述压垫包括平面状的支撑结构(2)以及多个金属的弹簧元件(3),如盘形弹簧或者螺旋弹簧或者板式弹簧或者波形弹簧,所述弹簧元件与支撑结构(2)连接并且分散地布置在所述支撑结构中或者所述支撑结构上。平面状的支撑结构(2)可以为金属板或平面织物、尤其是针织物、编结物、无纺织物或者织造织物。在最后一种情况下,弹簧元件(3)优选布置在所述平面织物的经线和纬线(6、7)的交叉点(18)处。此外,本发明涉及一种压垫压板单元或者压垫加热板单元。(The invention relates to a press pad (1, 1') for use in a hydraulic single-or multi-layer hot press, comprising a planar support structure (2) and a plurality of metallic spring elements (3), such as disk springs or helical springs or leaf springs or wave springs, which are connected to the support structure (2) and are arranged distributed in or on the support structure. The planar support structure (2) can be a metal plate or a planar fabric, in particular a knitted fabric, a non-woven fabric or a woven fabric. In the last case, the spring elements (3) are preferably arranged at the crossing points (18) of the warp and weft threads (6, 7) of the flat woven fabric. Furthermore, the invention relates to a pressure pad press plate unit or a pressure pad heating plate unit.)

1. A press pad (1, 1') for use in a hydraulic single-or multi-layer hot press, comprising a planar support structure (2) and a plurality of metallic spring elements (3) which are connected to the support structure (2) and are arranged distributed in or on the support structure.

2. Pressure pad (1, 1') according to claim 1, characterized in that the support structure (2) is a metal plate, preferably a press plate or a heating plate, of a single-or multi-layer hot press, and the spring element (3) is adhesively and/or soldered and/or welded and/or form-fittingly connected with the metal plate.

3. Pressure pad (1, 1') according to claim 1 or 2, characterized in that the support structure (2) is a flat fabric, in particular a knitted or knitted fabric or a non-woven or woven fabric, wherein at least a part of the wires (6, 7) constituting the flat fabric are made of or contain a metal, wherein the metal is in particular composed of brass, copper, bronze, steel, in particular refined steel.

4. Pressure pad (1, 1') according to one of claims 1 to 3, characterized in that the support structure (2) consists of a metal plate and a flat fabric, wherein the spring elements (3) are connected with the flat fabric and/or the metal plate.

5. Pressure pad (1, 1') according to one of claims 1 to 4, characterized in that the spring element (3) is a cup spring (8) or a coil spring or a leaf spring or a wave spring.

6. Pressure pad (1, 1') according to one of claims 3 to 5, characterized in that the spring elements (3) are connected, in particular form-fittingly connected, to the threads (6, 7) of the flat woven fabric, wherein the spring elements (3) are preferably arranged at the crossing points (18) of the warp and weft threads (6, 7) of the flat woven fabric.

7. A press pad (1, 1') as claimed in claim 6, characterized in that the spring element (3) has a through-hole (17) through which the threads (6, 7) of the flat fabric are guided.

8. Pressure pad (1, 1') according to claim 7, characterized in that the spring element (3) has at least four through-holes (17), of which two are guided through by warp threads (6) and the other two are guided through by weft threads (7).

9. Pressure pad (1, 1') according to one of claims 1 to 8, characterized in that the spring elements (3) are arranged, in particular in mutually intersecting rows, in particular at equidistant intervals from each other along the weft and/or warp threads (6, 7).

10. Pressure pad (1, 1 ') according to one of claims 1 to 9, characterized in that the spring elements (3) are partially embedded in an elastic material, preferably a silicone elastomer or a fluorosilicone elastomer or a polymer blend or copolymer of the two elastomers, wherein the spring elements (3) preferably constitute a part of the surface (26) of the pressure pad (1, 1 '), respectively, on mutually opposite sides of the pressure pad (1, 1 ').

11. Pressure pad (1, 1') according to claim 10, characterized in that particles for increasing the thermal conductivity, in particular particles consisting of metals or minerals, are contained in the elastomeric material, preferably in particular in the form of nanoparticles, respectively.

12. A pressure pad platen unit or pressure pad heating plate unit comprising a pressure pad (1, 1') according to at least one of claims 1 to 11.

Background

Artificial boards, such as plywood, particle board, MDF board, HDF board or composite board, are usually coated by means of high-grade cellulose paper impregnated with an aminoplast resin. The papers may be printed with different designs or may be solid. The aminoplast resin consists of a precondensed melamine/formaldehyde resin or a mixed resin consisting of melamine and urea or phenol and cresol. The precondensed resin is in the liquid phase and the web is therefore fully saturated in a special impregnation tunnel with drying and cooling zones. In the heated drying zone, the polycondensation of the resin is again activated at a temperature between about 150 ℃ and 170 ℃ and is interrupted in the subsequent cooling zone according to the desired degree of polycondensation. The paper web thus obtained has a low moisture content and is solid and can therefore be transported for further processing in a press apparatus, in particular in the form of a hydraulic single-or multi-layer press.

The impregnated decorative paper is now used with a correspondingly selected wood-based panel in a hydraulic hot press, which can have either one or alternatively a plurality of layers. The precondensed aminoplast resins first become liquid under the action of pressure and temperature, wherein, by further molecular crosslinking, the viscosity of the liquid resin increases again and finally a solid surface is formed. A metal press plate having a structured, matte or shiny surface is contacted with decorative paper or an aminoplast resin to form the surface. The platens are typically chrome plated to protect the surfaces from wear and damage. The chromium layer also has the function of enabling the resin layer to be separated intact after the coating process (coating). Metallic press plates can be made of brass, alloy MS64 or AISI410 or AISI630, for example, wherein nowadays steel plates are preferred because of their higher hardness and longer service life.

The artificial boards have different apparent densities depending on the field of use and therefore also need not beThe same pressing pressure. When manufacturing floorboards (flooring boards) from HDF (high density fiberboard) material, the specific pressing pressure is particularly high and is about 400N/cm²To 600N/cm²Because the apparent density of the floor is about 800N/cm³To 1000N/m³. The blank plate itself has a very low damping effect and for this purpose has thickness tolerances which have to be compensated for during the coating process. All plate materials in principle have more or less large thickness tolerances. Further tolerances are produced by the respective press device itself, in particular the press plates and heating plates present in the press device.

If the aforementioned tolerances are not compensated, significant surface defects may occur in the surface of the coated wood-based board. The press device is therefore basically equipped with a corresponding press pad, in particular in the form of a pressure-compensating cloth or mat. The pressure pad is fixed between the heating plate and the pressure plate. The pressure pad must be thermally stable, i.e. must not decompose even at temperatures between 200 ℃ and 230 ℃, must have a good elastic effect or restoring force and a high thermal conductivity. A uniform pressure distribution and a rapid heat flow during the coating process are particularly important factors here. As mentioned before, the aminoplast resin becomes liquid again under the action of pressure and heat, wherein formaldehyde and water are released in the form of vapor. Since the resin is located between the metal press plate and the wood-based plate, the system is hermetically closed and the corresponding steam must diffuse into the paper web and the plate surface within a short time as dictated by the timing of the press equipment. Otherwise, due to the uneven pressing pressure, the bubbles will remain enclosed in the resin layer and will subsequently appear as milky, turbid spots on the surface. Such a plate with defects is not suitable for further applications. Due to the higher temperature of the heating plate (about 200 to 230 c), the choice of materials suitable for the pressure pad is relatively small. Over the last decades, elastomeric materials based on silicone rubber have proven suitable, wherein also blended materials and copolymers made of silicone rubber and fluorosilicone rubber or fluororubbers are used. Pressure pads according to the prior art are usually designed as a fabric with threads containing an elastomeric material or as a coated pad with an internal, usually metallic, supporting fabric.

A press pad with a fabric comprising a copolymer consisting of silicone and fluorosilicone rubber is known from patent document EP 1136248A. The copolymer is incorporated into the press pad in the form of a coated yarn for use as warp or weft. To improve thermal conductivity, metallic additives may be added to the elastomeric material.

Patent document EP 0735949 a1 describes a pressure pad having a silicone elastomer in one wire system and a metal wire in another wire system. The wire with the silicone elastomer can be designed as a sheathed core wire, wherein the wire core is formed from a metal wire and the wire sheath is formed from the silicone elastomer.

In the pressure pad known from DE 202012005265U, the defined lines are formed by heat-conducting lines, which, because of their orientation as perpendicular as possible to the surface of the pressure pad, are intended to achieve a more direct heat transfer.

Furthermore, EP 1300235 a and DE 2319593 a each disclose a press pad made of a metal fabric, which is subsequently coated with a substantially entire surface of silicone rubber. According to the teaching of patent document EP 1300235 a, the metal wire facing the surface of the pressure pad, in particular the loops or rings of said metal wire, are exposed by rolling during the coating process in order to achieve in this way a metallic contact between the pressure pad and the heating plate or pressure plate. In addition, the silicon elastomer may be mixed with particles to improve thermal conductivity. A disadvantage in this respect is that the addition of additives in the form of particles to the elastomer matrix has a negative effect on the elasticity of the elastomer matrix and its recovery properties.

The known pressure pads generally have the disadvantage of material fatigue, in particular in terms of the restoring or elastic effect of the pressure pad. The known silicone elastomers and alternatively the used press pads with threads made of aromatic polymers, in particular polyamides, have such an aging process at a continuous temperature above about 200 ℃ to 230 ℃. The pressure pads must therefore be replaced relatively early, which results in downtime of the press equipment and causes an increase in environmental load, in particular because pressure pads made of known materials or material mixtures are very difficult to recycle. Particularly when coating floors, pressure pads with high recovery values even after prolonged use and with very high heat transfer capacity are required. Up to now, it was not possible to modify the dimensions of the board with the known press pads when coating HDF boards for the floor area ("laminate"), since the press pads are strongly compressed at the chosen board dimensions and then changed to larger dimensions leave marks on the press material.

Furthermore, the press pad according to the invention can also be used in so-called high-pressure press installations, in which so-called high-pressure laminates, for example in the form of substrates for printed circuit boards, are produced by hot pressing. DE 20011432U discloses a pressure pad for this application, which consists of a heat-resistant plastic nonwoven and a PTFE film bonded to the plastic nonwoven. No metal is required in such a high pressure pad due to the long cycle time of the pressing process.

Technical problem

The object of the invention is to provide a pressure pad which is distinguished by a very high elastic recovery, by a fatigue-free retention over the longest possible period of time, and by a high thermal conductivity.

Technical scheme

The invention is based on a pressure pad of the type mentioned at the outset, in which the problem is solved by a plurality of metallic spring elements which are connected to the support structure and are arranged distributed in or on the support structure.

Metallic spring elements have two advantages over elastomeric or aromatic polymer materials: on the one hand, the metallic spring element has a very high modulus of elasticity, i.e., a high spring stiffness, due to the metallic material. This means that the restoring force is already very high even when the spring element is deflected, i.e. deformed, relatively little. Metals having a high modulus of elasticity in combination with a high elongation at break are, for example, steels, in particular spring steels. In principle, other metallic materials, such as copper alloys (e.g. beryllium copper), are also conceivable. Despite the large spring constant, the metal spring retains its restoring properties over a very long period of time, so that the pressure pad according to the invention has a correspondingly long service life. On the other hand, metallic spring elements have a very good thermal conductivity, so that the thermal conductivity of the pressure pad according to the invention is influenced positively in particular in comparison with pressure pads having a large proportion of an elastomer material, which in principle has the feature of a relatively poor thermal conductivity.

The invention therefore allows for the first time the use of a pressure pad element which is equally advantageous both in terms of its heat-conducting properties and in terms of its spring properties (restoring capacity). In the prior art, different compositions are always used in order to optimize the two properties (thermal conductivity and recovery capacity), for example an elastomer material for the recovery capacity and a metal material, in particular a metal wire, for good thermal conductivity. Within the scope of the invention, the support structure can be formed, for example, by a metal plate, preferably a press plate or a heating plate, of a single-layer or multi-layer hot press. In both cases described above, the spring element is connected to the pressure plate or the heating plate, in each case forming a unit consisting of pressure plate and spring element or heating plate and spring element. The spring elements are preferably adhesively bonded and/or soldered and/or welded to the respective plate and/or connected in a form-fitting manner, for example by inserting the spring sections into corresponding openings or through-holes in the plate.

As an alternative to the support structure in the form of a plate, a support structure in the form of a flat fabric is also conceivable according to the invention. The flat fabric can be designed in particular as a knitted or knitted fabric or as a non-woven or woven fabric, wherein at least a part of the threads forming the flat fabric are made of or contain a metal, wherein the metal can in particular be made of brass, copper, bronze, steel, in particular refined steel.

It is also conceivable to combine metal sheets with a flat textile to form the support structure. In this variant, the spring element is preferably connected to the flat fabric and/or the metal sheet. Furthermore, a suitable connection between the flat fabric and the metal sheet is required, for example in the form of an adhesive or a welded or soldered or form-fitting connection between the threads of the flat fabric and the metal sheet, for example by guiding the threads of the flat fabric through holes or openings in the metal sheet.

Preferably, a disk spring or a coil spring or a leaf spring or a wave spring can be used as the metallic spring element.

According to a preferred embodiment of the invention, the spring element is connected, in particular positively connected, to the threads of the flat woven fabric, to be precise preferably arranged positively connected at the crossing points of the warp threads and weft threads. For this purpose, the spring element can have through-openings through which the threads of the flat fabric, in particular the aforementioned warp and weft threads, pass. A particularly preferred embodiment is formed by a pressure pad in which the spring elements each have four through-openings, two of which are penetrated by warp threads and the other two of which are penetrated by weft threads. In this way, the position of the intersection of the respective lines can be designed particularly advantageously.

In order to achieve as good a uniformity as possible of the spring properties of the press pad, the spring elements should be arranged, in particular, in mutually intersecting rows, further in particular, at equidistant spacing from one another along the weft and/or warp threads of the woven fabric used as the support structure. In this way, a particularly simple arrangement of the matrix structure and the spring elements is produced.

The invention also provides in terms of design that the spring elements may be partially embedded in an elastomeric material, preferably in a silicone elastomer or a fluorosilicone elastomer or a polymer or copolymer blend of the two elastomers. The segments or sections of the spring element preferably form parts of the surface of the pressure pad on two mutually opposite sides of the pressure pad. In this way, particularly good heat transfer is achieved, since the transfer of heat on both surfaces of the pressure pad is produced by the contact surfaces of the pressure pad with the metal of the pressure plate or heating plate. In this connection, it is particularly advantageous if the spring element extends completely through the entire thickness of the pressure pad in order to optimize the heat transfer.

The combination of the spring element in combination with the metal and the elastomeric material may be desirable to add particulate matter to the elastomeric material in order to increase the thermal conductivity of the pressure pad. These are, in particular, particles made of metals or minerals, wherein these particles should preferably be configured as nanoparticles.

Example (b):

the invention will be explained in more detail below on the basis of an embodiment shown in the drawing. In the drawings:

figure 1 shows a schematic view of a pressure pad according to the invention,

figure 2 shows a vertical section through the spring element shown in figure 1,

figure 3 shows a schematic view of another pressure pad according to the invention,

figure 4 shows a vertical section through the pressure pad shown in figure 3,

figure 5 shows a vertical section through a single-layer hot press according to the prior art,

FIG. 6 shows a vertical section through a press pad-heating plate unit according to the present invention and

fig. 7 shows a vertical section through a press pad-platen unit according to the present invention.

The embodiment shown in fig. 1 comprises a press pad 1' according to the invention for use in a hydraulic single-or multi-layer press. As provided in the prior art, the press sleeve 1 is arranged between a heating plate and a press plate of a single-layer or multi-layer hot press in order to compensate for thickness tolerances present in the press plate or heating plate and at the same time to enable heat emitted from the heating plate to be transferred to the press plate.

The pressure pad 1 according to the invention comprises a planar support structure 2 and a plurality of spring elements 3. The planar support structure 2 is designed in the form of a woven fabric comprising two thread systems 4, 5, namely a warp thread 6 and a weft thread 7. The warp threads 6 and the weft threads 7 are designed in the form of a wire braid made of brass and are interwoven with one another to form a plain weave. Thus, the warp threads 6 extend alternately above and below the weft threads 7, or the weft threads 7 extend alternately above and below the warp threads 6.

The spring element 3 of the pressure pad 1 is hooked in the form of a metal cup spring 8. When used in a single-layer or multi-layer hot press, the cup spring 8 in the undeformed state is in contact with the heating plates of the single-layer or multi-layer hot press only with the circularly encircling upper edge 9 and with the likewise circularly encircling lower edge 10 with the press platens of the single-layer or multi-layer hot press, wherein the two edges 9, 10 each form a circular contact line 11, 12. However, an opposite orientation of the spring element 3 is also conceivable, in which the upper edge 9 is in contact with the pressure plate and the lower edge 10 is in contact with the heating plate.

Furthermore, the cup spring 8 has a beveled (conical) side section 15, which causes the diameter of the first contact line 11 to be reduced in comparison with the diameter of the second contact line 12. The section through the cup spring 8 is shown in fig. 2 and shows a truncated cone shape.

During the pressing process of the single-layer or multi-layer hot press, the spring element 3 is deformed such that a flat upper contact surface 13 is formed. While forming a flat lower contact surface 14. When used in single-layer or multilayer hot presses, one of the contact surfaces 13, 14 is in contact with the heating plate and the other contact surface 13, 14 is in contact with the press plate. The cup spring 8 is thus substantially in the shape of a hollow cylinder during pressing.

In the edge region 16, the disk spring 8 is provided with four through-openings 17 which are each arranged at an angle of 90 ° to one another in a circle and which, for the sake of simplicity of production, can also each be open toward the circular outer edges of the disk spring 8, in order to make it unnecessary to "thread" the weft threads 7 or warp threads 6 with thread ends, but rather to be able to "thread" laterally. The wires 6, 7 of the wire systems 4, 5 are each guided through two opposite through-openings 17 of the spring element 3, while the remaining two through-openings 17 are provided for receiving the wires 6, 7 of the respective other wire system 4, 5. The crossing points 18 of the warp threads 6 and the weft threads 7 correspond here substantially to the central axis 19 of the spring element 3. The cup springs 8 are arranged equidistantly in the pressure pad 1 and form rows crossing at 90 ° in the pressure pad 1. Therefore, the pressure pad 1 can be easily rolled and transported.

Since the untensioned (non-active) length 21 of the cup springs 8 is increased compared to the diameter 20 of the warp threads 6 and weft threads 7, the upper contact surface of the pressure pad 1 is formed by the integral formation of the upper contact surface 9 of the individual cup springs 8, while the lower contact surface of the pressure pad 1' is formed by the integral formation of the lower contact surface 10 of the individual cup springs 8. It can thereby be ensured that different thicknesses in the heating plate and/or pressure plate are compensated for by means of the elastic effect of the cup springs 8, wherein the degree of the elastic effect is changed by means of a change in the outer diameter 22, a change in the inner diameter 23, a change in the material thickness 24 and a change in the untensioned length 21 of the cup springs 8 and can thus be adapted to the specific requirements of the single-layer or multi-layer hot press. Thus, the warp threads 6 and the weft threads 7 do not come into contact with the press plate or the heating plate. Due to the heat-conducting properties of the cup springs 8 which extend very directly, i.e. over a short path, through the press plate, the heat emitted from the heating plate can be transferred well to the press plate.

Fig. 3 shows a further embodiment of a pressure pad 1' according to the invention. The press pad 1' likewise comprises a planar support structure 2 in the form of a woven fabric and a plurality of metallic spring elements 3. In contrast to the pressure pad 1 'shown in fig. 1, the pressure pad 1' according to fig. 2 has a double-sided coating 25 of a thermally stable elastomer material. Thus, the pressure pad 1' shown in fig. 1 is substantially embedded in the elastomeric material. In order to ensure that the heating plate or pressure plate continues to be in contact only with the spring elements 3, the coating 25 is removed in the region of each spring element 3, as can be clearly seen in fig. 4. The lower and upper surfaces 26, 26 of the pressure pad 1' are thus partly formed by the spring element 3.

Figure 5 shows a single layer hot press 27 according to the prior art. The single layer hot press 27 includes two heated platens 28 and two platens 29. According to the invention, as already specified in the prior art, the press pads 1', 1 according to the invention are each arranged between a heating plate 28 and a press plate 29 of a single-layer hot press 27. Between the two press plates 29 there is placed a wood-based board 30 to be coated, which is covered by a decorative paper not shown in the figures. The decorative paper is attached to the artificial board 30 by heat from the single layer hot press 27 and pressure applied to the artificial board 30.

The embodiment of a press pad and heating plate unit 31 according to the invention shown in fig. 6 comprises a press pad 1, 1' according to the invention and a heating plate 28 of a single-or multi-layer press. Here, the pressure pads 1, 1' are bonded to the heating plate 28 so as to form a single component.

Fig. 6 shows an embodiment of a pressure pad platen unit 32 according to the present invention. In contrast to the press pad and heating plate unit 31, the press pads 1', 1 according to the invention are not connected to the heating plate 28, but rather to the press plate 29 of a single-layer or multi-layer press, for example by gluing, and thus likewise form a single component.

List of reference numerals

1' pressure pad

1 pressure pad

2 support structure

3 spring element

4-wire system

5-wire system

6 warp threads

7 weft

8-disc spring

9 upper edge

10 upper edge

11 contact line

12 contact wire

13 upper contact surface

14 lower contact surface

15 side section

16 edge region

17 through hole

18 cross point

19 central axis

20 diameter

21 untensioned length

22 outside diameter

23 inner diameter

24 material thickness

25 coating layer

26 surface of

27 single layer hot press

28 heating plate

29 pressing plate

30 artificial board

31 press pad heating plate unit

32 pressure pad pressing plate unit