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DE-102025145203-A1 - Press pads with threads featuring a mesh of metal threads

DE102025145203A1DE 102025145203 A1DE102025145203 A1DE 102025145203A1DE-102025145203-A1

Abstract

The invention relates to a press pad with a fabric comprising threads of a first thread system and threads of a second thread system running perpendicular to the threads of the first thread system, wherein the threads of the first thread system and the threads of the second thread system are interwoven to form a bond, wherein at least a part of the threads of at least one of the two thread systems contains or consists of an elastomeric material at least partially, and wherein at least a part of the threads of at least the other of the two thread systems contains or consists of a metal component. In order to achieve the most uniform heat distribution over the material being pressed and rapid heat transfer through the press pad, it is proposed that the threads containing or consisting of the elastomer material, preferably all of these threads, are sheathed with a braid (6, 6', 6") of metal threads (5, 5', 5"), wherein the metal threads (5, 5', 5") forming the braid (6, 6', 6") - during pressing operation under the influence of a pressing pressure on the press pad - form at least a part of the surface of the press pad that comes into contact with a pressing plate or a heating plate.

Inventors

  • Rolf Espe
  • Stanislav Sapasnik

Assignees

  • HUECK RHEINISCHE GMBH

Dates

Publication Date
20260513
Application Date
20251104
Priority Date
20241111

Claims (10)

  1. Press pad comprising a fabric with threads of a first thread system and threads of a second thread system running perpendicular to the threads of the first thread system, wherein the threads of the first thread system and the threads of the second thread system are interwoven to form a bond, wherein at least a portion of the threads of at least one of the two thread systems contains or consists of an elastomeric material at least partially, and wherein at least a portion of the threads of at least the other of the two thread systems contains or consists of a metal component, characterized in that the threads containing or consisting of the elastomeric material, preferably all of these threads, are sheathed with a braid (6, 6', 6") of metal threads (5, 5', 5"), wherein the metal threads (5, 5', 5") forming the braid (6, 6', 6") - in pressing operation under the influence of a pressing pressure on the press pad - form at least a portion of the surface of the press pad that comes into contact with a pressing plate or a heating plate.
  2. Press pads Claim 1 , characterized in that at least a part of the threads of at least one of the two thread systems, preferably the threads containing or consisting of the elastomer material, preferably all of these threads, each have - a core thread (2) by means of which a predominant proportion of the tensile force acting on a thread can be transmitted, and - a thread sheath (4) enclosing the core thread (2), which consists of elastomer material.
  3. Press pads Claim 2 , characterized in that the core threads (2) are made of metal, in particular steel, preferably stainless steel, or copper or brass or bronze, or of a polymer material, in particular of an aromatic polyamide or of a melamine resin, wherein the aforementioned core threads (2) are preferably composed of a plurality of individual filaments which are twisted, stranded or roped together.
  4. Press pads Claim 2 or 3 , characterized in that the sheath (4) is formed by extrusion of an elastomer material around the core thread (2) and preferably consists of a silicone elastomer or a fluorosilicone elastomer or a blended elastomer of a silicone elastomer and a fluorosilicone elastomer, or is formed by wrapping or twisting the core thread (2) with at least one sheath thread made of a polymer material, in particular an elastomer material or a high-strength polymer material, preferably an aromatic polyamide or a melamine resin.
  5. Press pad after one of the Claims 1 until 4 , characterized in that the first thread system is formed by weft threads (1) of the fabric and the second thread system is formed by warp threads of the fabric.
  6. Press pad after one of the Claims 1 until 5 characterized in that the fabric is made in plain weave, wire weave, twill weave, rib weave or Panama weave.
  7. Press pad after one of the Claims 1 until 6 , characterized in that at least a part of the threads of only one of the two thread systems, preferably the weft threads (1), contain an elastomer component, preferably in the form of a thread sheath (4) arranged around a core thread (2).
  8. Press pad after one of the Claims 1 until 7 , characterized in that the braid (6, 6', 6") consists of metal threads (5, 5', 5") made of steel threads, in particular stainless steel threads, and/or brass threads and/or copper threads and/or bronze threads and/or aluminium threads.
  9. Press pad after one of the Claims 1 until 8 , characterized in that the braid (6, 6', 6") of metal threads (5, 5', 5") lies close to the outer surface of the associated thread containing the elastomer material or is embedded in the outer surface of the associated thread containing the elastomer material.
  10. Press pad after one of the Claims 1 until 9 , characterized in that the number of metal threads (5, 5', 5") forming the braid (6, 6', 6"), which have a different orientation in the braid, is between 2 and 20, preferably between 3 and 10.

Description

Introduction The invention relates to a press pad with a fabric made of threads of a first thread system and threads of a second thread system running perpendicular to the threads of the first thread system, wherein the threads of the first thread system and the threads of the second thread system are interwoven to form a bond, wherein at least a part of the threads of at least one of the two thread systems contains or consists of an elastomeric material at least partially, and wherein at least a part of the threads of at least the other of the two thread systems contains or consists of a metal component. State of the art A pressure pad of the aforementioned type is, for example, made from the WO 2024/141250 A1 A known method exists. To increase the stability and service life of such a pad by reducing metal thread abrasion, both surfaces of the known press pad that come into contact with a press plate or heating plate during pressing operations are made exclusively of a non-metallic material. Specifically, metal threads are wound around threads made of a plastic material in such a way that the metal threads are completely embedded in the outer outline of the plastic thread or double thread (viewed in cross-section). Combined with a high thread density and a relatively strong bend in the threads running perpendicular to the threads containing the embedded metal threads, the metal threads never come into contact with either surface of the press pad. Therefore, no contact occurs between these metal threads and the metal material of the press plate or heating plate. Relative movements between the heating plate or press sheet on the one hand and the press pad on the other – these relative movements are caused by the constant temperature changes during the cyclic pressing operation of such press pads – reduce metallic abrasion on the metal threads surrounding the plastic threads and thus reduce wear on the press pad. This reduction in wear comes at the cost of a comparatively poor thermal conductivity of the press pad and therefore a comparatively long cycle time when heating the material being pressed. Press pads of the type discussed here are used in hydraulic single- or multi-stage heating presses and serve to equalize pressure within the press during the coating of various wood-based panels with decorative papers impregnated with thermoset resins. Most of these presses are so-called hydraulic single-stage presses and are referred to as short-cycle presses. These presses are operated with heated thermal oil. Depending on the type of coating and the wood-based panel, the specific pressing pressures range from approximately 200 N/ cm² to 1000 N/ cm² . The wood-based panels, such as plywood, particleboard, MDF, or HDF, are coated with decorative synthetic resin films in these presses. These synthetic resin films consist of crosslinkable thermoset resins such as melamine, urea, or mixed resins of both aforementioned types and are very sensitive to pressure and temperature differences during polycondensation in the presses. If the pressure and temperature distribution is not uniform, various defects can occur on the surfaces, such as resin foaming (also known as white spots) or opaque surfaces. Therefore, it is particularly important that the pressure pads ensure uniform pressure equalization and temperature transfer. Melamine-urea and phenolic resins belong to the thermosets, which become liquid under pressure and temperature. During this process, they release water and formaldehyde, and in combination with a controlled hardener concentration in the presses, form a solid, irreversible surface. The release products, such as water and formaldehyde, become gaseous during the pressing process and can only diffuse into the wood-based substrate or paper web, as the press plate seals the material gas-tight from above. Since the thermoset resin is initially liquid and then slowly transitions to a gel-like and finally solid state, depending on the hardener concentration and pressing temperature, the vapor diffusion process must occur in the liquid phase; otherwise, the aforementioned surface defects will result. This requires a pressing pressure higher than the vapor pressure of water, as otherwise the water vapor cannot be forced into the receptive layers. Especially in the production of flooring panels (particularly laminate flooring), which consist of MDF or HDF panels with very hard surfaces, uniform and rapid temperature transfer and homogeneous pressure distribution are of particular importance. These panels have a density of 800 kg/ m³ and 1000 kg/ m³ and generally lack inherent springiness. Many presses exhibit large pressure and temperature differences, making it crucial that the press cushions can compensate for these variations. For some time now, compression pads have been widely used, achieving their spring and pressure distribution properties through the use of elastomeric material, particularly elastomeric t