EP0761135B1 - Usage of a hollow panel made of acrylic glass - Google Patents

Abstract

Furniture is made using plates of acrylic glass, contg. cavities, in place of MDF boards. Pref. the hollow cavity plates include at least two flanges (2a, 2b), forming the cavities with webs (3a, 3b), the end webs (3b) being thickened. Thickness of the flanges is pref. 2 - 6 mm and thickness of the end webs is larger than the thickness of the thickest flange. At least the parts which are visible after assembly are pref. not transparent but are coloured.

Description

The invention discloses a novel use per se well-known twin-wall sheets made of acrylic glass.

Twin-wall sheets made of thermoplastic materials in a transparent version for almost 25 years now Glazing in commercial and private areas used. In principle, twin-wall sheets consist of two or more belt plates with intermediate ones Vertical and / or diagonal bars. This structure gives the panels have high rigidity with low weight and good thermal insulation properties. Based on these Properties as well as the high light transmission and Find weather resistance with good fire behavior Twin-wall sheets, preferably made from the Polymethyl methacrylate, polycarbonate or plastics Polyvinyl chloride, usually used in commercial Area, e.g. B. for greenhouses, industrial and Sports halls, and in the private sector, e.g. B. for pergolas, Terrace canopies and winter gardens.

Up to now, polyolefin hollow chamber panels have been used as Packing material.

Twin-wall sheets are made by extrusion using a Cross section of the corresponding tool by simultaneous Education of the outer and middle layers (outer and Middle belts) and the webs. After the exit of the The outer belts become hollow strands from the extrusion die when passing through a vacuum forming channel (calibration) cooled below the softening temperature. The Middle layers and webs remain thermoplastic longer than the outer layers. Since they are not supported, the middle classes tend to be horizontal Extrusion for sagging between the webs. This Effect can be reduced if the middle layers are very run thin, because then less heat to Below the softening temperature, and if you extrude very slowly.

The most common embodiment is Double-wall / triple-wall plate, in which the webs in regular distances to each other perpendicular to the Plate level run, so that the image of lined up rectangular chambers.

Because of the anisotropic behavior of such plates in the With regard to the bending stiffness were especially for Products from PMMA other geometries such as B. the so-called Truss geometry developed.

With these geometries, the webs form with the plates an angle of approximately 45 °, which is due to improved Transfer of shear forces to lower stresses and to a higher rigidity, with a similar basis weight, leads.

As a result of these requirements, when installing these products further support distances of the load-bearing elements be selected, which increases the cost of materials for the Support structure and the time required for installation Reduce.

Inclined multi-wall sheets are known for polycarbonate become (EP-A-0 530 545), in which two in the given Distance parallel plates through both inclined webs and perpendicular ones Vertical webs are connected.

The fact that one part of the webs - seen in cross section - connects the upper and lower plate in a zigzag, while the other part starts at the nodes of the inclined webs with the upper or lower plate and runs perpendicular to the opposite plate, the inclined web multiple plate made of polycarbonate have a sufficient load capacity, since the buckling is shifted beyond the maximum load, which is defined so that the deflection at a load of 750 N / m ^{2 is} not more than 5%, based on the width of the plate.

From EP-A-0 054 856 there are many possible cross sections for Hollow wall panels are known in which at least part of the Bridges in each periodically recurring section is slanted. Figures 3e and 3f according to EP-A-0 054 856 each show geometries 3 belts, but only in the case of the embodiment according to Figure 3e matured for production.

In addition, there have also been attempts to achieve multi-wall sheets with increased thermal insulation with largely exclusion of light losses, whereby, inter alia, EP-A-0 286 003 has made known a multi-wall sheet which, compared to, for example, three-wall sheets, has a k-value of in reduced by 30% about 1.8 W / m ² K. Despite the avoidance of an increase in the basis weight, the plate presented in EP-A-0 286 003 has not established itself on the market.

EP-A-0 109 388 describes the use of a Composite plate known that a multi-wall sheet made of plastic contains, in which at least two continuous plates are connected by webs, the Web plate on at least one of its two sides with a hardening layer made of plastic material the web plate is connected to different plastics, that between the web plate and the hardening layer especially an adhesion-promoting compensation layer is provided and that the cavities in the web plate may are foamed with a plastic foam. The one shown Composite panel is used to manufacture curved panels, especially for glass domes u. Like., by deformation in the heat or to produce curved, preferably with Molded articles coated with textile material by deformation in who uses heat.

Although there are many other publications that deal with the manufacture and use of Up to now, dealing with twin-wall sheets has been everyone known areas of application in common that they essentially refer to external roofing.

It has now been found that twin-wall sheets form Acrylic glass excellent as a replacement for wood-based panels, especially MDF boards, suitable for furniture production. Here, hollow chamber panels made of acrylic glass can be used according to the invention used both as front parts and as a body will.

Today, furniture and especially in Kitchen furniture area wood-based panels, especially the coated MDF board (i.e. medium density fiberboard) used. The MDF board usually consists of Lignocellulosic fibers and a synthetic binder and has the advantage that it has a high stability with a relatively easy to process. However, will e.g. B. a visible side with a high-gloss surface desired, the MDF board must either be high gloss lacquered or glued with a high-gloss veneer. Other decors and surface structures are made by Application of printed and / or embossed foils, mostly made of PVC, or by high pressure laminated paper.

The core of the MDF board is by coating or Painting then relatively permanent and the surface can also be scratch-resistant, the necessary for this However, materials make disposal or recycling difficult the composite body considerably, yes make it without previous Separation of the components almost impossible. The unmixed Separation, in turn, is too high, if at all possible Cost associated and therefore not practical. Also are the wood-based panels, but especially the MDF panels, usually not moisture resistant.

A material that is known to combine surfaces with the highest gloss as well as 100 percent recyclability is cast or extruded acrylic glass. There have already been attempts to use this material in the form of cast acrylic glass plates when creating furniture fronts that meet the requirement profile: "high-gloss surface and complete recyclability", but acceptance on the market has so far been rather low. Solid acrylic glass can satisfy the demands for complacency and high-gloss surface as well as for complete reusability without the dreaded effect of "downcycling", but it is very heavy and expensive in massive execution and so far mostly only for sample pieces, but not for mass production of parts suitable for the furniture industry, especially furniture fronts. In any case, the advantage of acrylic glass is that it is insensitive to moisture.

1. den Wunsch nach Glanz-Oberflächen zu befriedigen;

2. einen vollständig recyclierbaren Werkstoff bereitzustellen, und zwar ohne die Notwendigkeit vorhergehender Trennoperationen;

3. eine Platte zu schaffen, deren Oberfläche leicht dekorierbar ist, und zwar sowohl während der Fertigung (d. h. während der Extrusion durch Strukturierung) als auch nachträglich (Bedruckung); und

4. die ein relativ günstiges Gewicht bei ausreichender Stabilität aufweist.

By using hollow chamber panels made of acrylic glass as a replacement for the MDF panels, it is particularly advantageous according to the invention to

1. to satisfy the desire for glossy surfaces;

2. to provide a fully recyclable material without the need for previous separation operations;

3. to create a plate whose surface is easy to decorate, both during manufacture (ie during the extrusion by structuring) and subsequently (printing); and

4. which has a relatively favorable weight with sufficient stability.

It is fundamentally special in the context of the invention advantageous that due to the presence of Hollow chambers, the plates of the invention a clear one Weight saving compared to a massive embodiment provide while the surface of the acrylic glass high gloss or any decor to please Appearance of the entire plate can provide.

Since the bridges as well as the belts are made of acrylic glass, this is fulfilled Component according to the invention particularly advantageous Demand for 100% recyclability. There one used according to the invention in furniture manufacturing Twin-wall sheet under the depolymerization conditions of the 100% acrylic glass depolymerized into its components, is no when reprocessing used boards Effort in the form of separation of any components too operate. Rather, the entire material is recyclable regain. After preparing Old panels or fronts, for example by shredding or crushing in suitable mills or if necessary completely uncrushed, the invention used a standard Recycling processes for acrylic glass are subjected. Here, the acrylic glass depolymerizes and becomes Extraction, distillation and / or rectification without recovered any loss of quality as a monomer.

In principle, all are within the scope of the invention Acrylic glass known as twin-wall sheet geometries Furniture plates can be used. So plates with two, three or four belts with vertical bars or sloping bars or combinations thereof.

In any case, however, the use of twin-wall sheets preferred, the at least two belts as well as these below Forming spacing webs from adjacent hollow chambers have, the terminal webs of the edge Chambers are reinforced. Through a thicker training of the terminal webs of the respective outer chambers succeed particularly advantageous to use for the production of To facilitate furniture, because the thicker edges Allow post-processing of the shapes. Beyond that overall, the impact resistance of the wood-based and especially usable MDF board replacement Twin-wall sheets improved.

The thickness of the straps is generally not critical. The Thickness should, however, be sufficiently large, on the one hand sufficient overall stability of the twin-wall sheet guarantee, and on the other hand, a flatness of the entire plate can be reached. Is the thickness of the straps too low, so arise in the manufacturing process Double wall plate fluctuations in thickness, especially in the areas of the bridges, which if possible are to be avoided. Hollow chamber panels are therefore preferred made of acrylic glass as a replacement for MDF boards in the Furniture manufacturing uses the thickness of the straps is between approx. 2 and 6 mm. Is the thickness of the straps over 6 mm, so the components as furniture fronts are already closed heavy, while at a thickness below 2 mm, like mentioned a u. U. insufficient stabilization of the Belt thickness in the area of the webs is reached.

The strength or thickness of the terminal webs Hollow chamber panels to be used according to the invention is in Regarding the thickness of the straps preferably to be chosen so that the thickness of the terminal webs of the marginal chambers the twin-wall sheet is equal to or greater than the thickness of the straps, especially as that of the strongest strap. In order to will be used for the entire post-processing of the molds Sufficient material padding for edges and edges Provided, which particularly in the Reworking or unintended during assembly Damage to the twin-wall sheets is avoided.

Because of the simplicity of manufacture and the low Price are twin-wall sheets with vertical webs for the use according to the invention is sufficient and special prefers. Furthermore, that is particularly preferred Use of a twin-wall sheet in the form of a Inclined slab double plate or a truss plate is.

Although the use of transparent twin-wall sheets would be conceivable in the furniture industry, it is over Aesthetic reasons, however, by far preferred plates use at least in the after assembly of the Hollow-wall panels not visible parts of the panels are transparent but colored. It can be done with the A number of pigments familiar to the person skilled in the art produce aesthetically pleasing colors. these can furthermore with certain effects, such as gloss, structure, metallic, etc., can be combined. Basically everyone is available on the market and known to the expert Compounds suitable for coloring acrylic glass masses.

The well-known twin-wall sheets made of acrylic glass preferably used according to the invention as furniture fronts. Such fronts are with all standard materials can be combined. So the front can be made from a twin-wall sheet consist, while the body of wood-based panels is made.

However, the acrylic hollow chamber panels can do just as well for the production of carcasses, i.e. for the production of the massive, the actual shape of the furniture Partly, are used. This embodiment has the Advantage particularly easy with sufficient stability be. In this case, the fronts can also go out Acrylic double-wall sheets also from another Material.

The acrylic hollow chamber panels are preferred Creation of pieces of furniture or entire furniture systems suitable, which consist entirely of acrylic glass. Possible in this context is the combination with partial or completely solid sheets made of cast acrylic glass. The body made of solid acrylic glass is useful during the front or door is made of cellular sheet material.

Fronts and carcasses can be used to manufacture furniture made of twin-wall sheets, if necessary in combination with massive acrylic glass parts or other materials are processed in a manner known per se. So one can Front in the form of a twin-wall sheet with any Body (hollow panel made of acrylic glass, solid acrylic glass, Wood-based panels, MDF panels etc.) z. B. by so-called pot hinges or pot hinges can be connected. To fasten these connecting elements - as by known other conventional furniture materials - corresponding openings in a belt of the twin-wall sheet introduced, for example by drilling or milling. It should be emphasized that the strength of the Hollow wall panels with a belt thickness of 2 to 6 mm without further to accommodate when using the furniture elements occurring forces is sufficient.

The twin-wall sheets to be used according to the invention become advantageous through continuous extrusion produced. By training the Exit nozzle profile for the manufacture of the plate extruder used can be any lattice or truss-like arrangement of the webs (Stiffening partitions) can be obtained that the Hollow plate profile not only in the longitudinal direction, but also also in its width with relatively little material give a high moment of resistance, even with relatively low overall profile height. You get Here a piece goods, with a to the requirements of Furniture industry adjustable width. Would be preferred e.g. B. Widths to the grid dimensions (standard width for Kitchen furniture), for example about 600 mm are. The web distances are generally free selectable, since the webs are essentially used as spacers serve between the individual belts. Especially for the Bar spacing is preferred for use as a furniture element, which correspond approximately to the entire plate thickness.

In the following the invention is based on a Embodiment with reference to the accompanying Drawing explained in more detail.

The figure shows a schematic, partially broken away cross section with a hollow plate profile vertical stiffening bars.

In the figure, reference numeral 1 means a replacement of wood-based panels, preferably MDF, in the Hollow wall panel to be used for furniture manufacturing. The Hollow chamber panel is made of acrylic glass. The cut took place transversely to the longitudinal direction of the plate 1.

The plate 1 has so-called belts 2a, 2b, which in are arranged substantially plane-parallel to each other. The Belts 2a, 2b are made up of essentially vertical webs 3a, 3b spaced. Belts 2a, 2b and webs 3a, 3b are integrally formed with each other. Two adjacent ones Bridges 3a, 3a or 3a, 3b form with the upper belt 2a and a hollow chamber 4a, 4b from the lower belt 2b.

The chambers 4a, 4b run parallel and parallel to one another to each other in the longitudinal direction of the plate 1. If a chamber has only a single immediately adjacent chamber, then it is an edge-side chamber 4b. The edge-side chambers 4b are of webs 3a and each limited to a terminal web 3b. It can be seen that the Thickness of the webs 3b is greater than the thickness of the webs 3a, the thickness of the webs 3b roughly the thickness of the straps 2a or 2b.

Claims (7)

1. Use of cellular panels made of acrylic glass as a substitute for derived timber product panels, in particular MDF panels, i.e. medium-density fibre panels, in furniture manufacture.
2. Use according to claim 1,
   characterized in
   that the cellular panels (1) comprise at least two flanges (2a, 2b) spaced apart by means of webs (3a, 3b) so as to form adjacent cavities (4a, 4b), the end webs (3b) of the edge-side cavities (4b) being strengthened.
3. Use according to claim 1 or 2,
   characterized in
   that the thickness of the flanges (2a, 2b) is between 2 and 6 mm.
4. Use according to claim 3,
   characterized in
   that the thickness of the end webs (3b) of the edge-side cavities (4b) is greater than the thickness of the thickest flange (2a, 2b).
5. Use according to claims 1 to 4,
   characterized in
   that the webs (3a, 3b) of the cellular panel (1) are vertical.
6. Use according to claims 1 to 4,
   characterized in
   that the cellular panel is an oblique-web double panel.
7. Use according to claims 1 to 7,
   characterized in
   that at least the parts of the panel which are visible after installation of the cellular panel are not transparent but tinted.

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