WO2010057787A2

WO2010057787A2 - Method for producing a sheet and subsequently produced sheet

Info

Publication number: WO2010057787A2
Application number: PCT/EP2009/064775
Authority: WO
Inventors: Walter Schiegl
Original assignee: Fritz Egger Gmbh & Co. Og
Priority date: 2008-11-20
Filing date: 2009-11-06
Publication date: 2010-05-27
Also published as: ES2562225T3; EP2349717A2; DE102008058345B4; HUE028674T2; WO2010057787A3; DE102008058345A1; EP2349717B1; PL2349717T3

Abstract

The invention relates to a method for producing a laminated sheet (1), wherein the following steps are carried out successively: providing a number of cellulose fibre webs (4) provided with an impregnation; forming layers, in which the cellulose fibre webs provided with impregnation are arranged one above the other; introducing the layers into a hot press; pressing the layers by increasing the temperature and pressure to give a base sheet; removing the base sheet from the hot press and coating the base sheet. Such a method guarantees an optimal quality with reduced pressing times despite the lack of use of a back cooling press. The invention further relates to a laminated sheet produced by said method.

Description

Method for producing a plate and plate produced thereafter

The invention relates to a method for producing a laminate plate and a laminate plate produced therefrom.

The known from the prior art plates of this type consist of a plurality of impregnated with phenolic resin layers of core papers, on whose at least one side a melamine resin impregnated decor paper is provided, the layer thus layered under increased pressure and at elevated temperature to a compact Plate are pressed. To increase the wear resistance, a transparent paper layer, the so-called overlay paper, may be provided on the decorative paper. This can be equipped with increased requirements in terms of abrasion resistance and / or scratch resistance with hard particles, such as corundum ((X-Al ₂ O ₃ )).

The basic characteristics, test specifications and

Requirements for these so-called decorative high pressure laminates (HPL) are defined in the European standards EN 438 part 1 to 7. It is here essentially distinguished by the thicknesses of 2 mm and larger or smaller than 2 mm. The latter are for gluing with a

Carrier material provided, while plates greater than 2 mm usually without carrier material, ie self-supporting, are used. The present invention relates preferably on laminated boards, also called laminated boards, and their production with a thickness of 2 mm and larger, but it is not limited to these.

The area of application of laminated boards is very diverse. So these are commonly used as so-called laminates in furniture construction as a coating for highly stressed surfaces such as worktops or edges, as so-called compact panels but also as self-supporting table tops, partitions or wall coverings. But also in the outdoor area, for example for the cladding of facades, their application is very common.

For the production of high-pressure laminates phenol resin impregnated Kraft papers to form a core and impregnated with melamine resin decor papers are laminated to form a decorative surface and pressed together at elevated temperature. The temperatures used are usually in the range of 130 ⁰ C, at specific pressures of 8 to 10 MPa. Usually, in the manufacture of laminate plates, recooling presses are used which cool the plates before opening the press in order to reduce the vapor pressure present due to the residual moisture present at high temperatures. Excessive vapor pressure in the plate would otherwise cause it to burst at the moment of opening the press. However, presses that allow re-cooling of the pressed material are very expensive in your plant

Acquisition and are also subject to the frequent Temperature changes very high thermal loads, which has a negative effect on their life.

Melamine resins have lower thermal stability than phenolic resins. At high pressing temperatures, discoloration of melamine impregnated decors may occur. In this context one also speaks of yellowing. The pressing temperature is therefore limited for this reason.

In order to avoid the steam surge effect described, it has been proposed in DE 25 46 115 A1 to provide a porous, vapor-permeable layer on the side of a stack of layers to be pressed facing away from the decor.

It is therefore the object of the present invention to provide a method for producing a laminate plate and a corresponding laminate plate, which ensures optimum quality at reduced pressing times despite the abandonment of the use of a recooling press.

The above-derived and indicated object is achieved according to a first teaching of the present invention by a method for producing a laminated panel, in which the following steps are carried out successively:

Providing a plurality of impregnated cellulose fiber webs,

Forming a lamination by stacking the cellulose fiber webs provided with the impregnation,

- retraction of the stratification into a hot press, Pressing the stratification while increasing the pressure and the temperature to a base plate,

- Extending the base plate from the hot press and

- Coating the base plate.

Furthermore, the object is achieved according to a second teaching of the present invention by a laminate plate, which is produced in particular by such a method, as will be explained in more detail below, wherein the laminate plate contains: a base plate having a plurality of impregnated provided, superimposed and pressed under increased pressure and elevated temperature cellulose fiber webs and - provided on at least one side of the base plate coating.

Advantageous embodiments of the method according to the invention and of the laminated panel according to the invention are the subject matter of the subclaims and will be described in detail below.

The most important point, unlike the prior art, is that the layered sheet is made by a 2-stage process. The production of the main body or the base plate and the coating are carried out separately. Although there are disadvantages due to the additional coating process, but are more than compensated by the possible faster production of the body. In addition, there is no longer the limitation on the coating by way of decorative paper, but it can almost any number of other known Coating process can be applied. Optionally, appropriate pretreatments by grinding, smoothing, especially thermal quenching, and / or the application of primers, primers and / or primers done. For selected coatings, plasma treatment of the surfaces may also be beneficial. It may also be advantageous in the case of different coatings if the layer from which the base plate is formed has at least one cellulose fiber web without impregnation, preferably such that the layer is provided with an outer layer on one side and / or on both sides, which is formed by at least one cellulose fiber web without impregnation. In this way, a better adhesion of a coating is ensured.

The reduced pressing time of such laminates produced results on the one hand by the lack of melamine resin impregnated decor paper and thus possible, higher pressing temperature of 155 ° C, preferably of about 185 ⁰ C, more preferably of about 205 ⁰ C. Such high pressing temperatures would in with Melamine resin impregnated decor papers lead to discoloration / yellowing, making these products unusable.

Another advantage lies in the possibility that

To grind base plate before coating, which results in much lower thickness tolerances, as in conventional laminates. In addition, this circumstance is above all very advantageous because it can be dispensed with expensive press plates. For one

Laminate surfaces are just the highest quality, high-maintenance press plates that are periodically cleaned and from time to time can also be refurbished, that is, need to be re-chrome, used to achieve a closed surface with the desired degree of gloss and the desired structure. These high-quality and maintenance-intensive press plates can be dispensed with by the 2-stage process.

An additional, effective measure for reducing the pressing time results from the possibility of providing a porous, water vapor-permeable layer on one or both sides of the stratification, ie between the base body and the press plates. The resulting surface roughness of the finished base body can be easily removed again by means of the subsequent sanding. As a result of the additional layer, for example a nonwoven or a film, in particular made of plastic, the water vapor arising from the residual moisture of the impregnated cellulose fiber webs can be improved over the surfaces of the stratification during the pressing. It is thus the inner vapor pressure reduced in the resulting laminate, whereby the described bursting of the plate when leaving the press can be avoided. A significant reduction of pressing time is thus achievable. It is preferred to provide the porous, water vapor permeable layer on both sides, otherwise, especially for larger

Plate thickness, asymmetric conditions exist, which can lead to distortion of the finished plates. Another advantage of the repeatedly usable porous, water vapor permeable layer is further that it also acts as a release film and thus always causes a slight detachment of the material to be pressed during press exit or opening of the press. Also, a possible contamination of the press plates is avoided. In addition to the high efficiency due to the reduced pressing time, resulting from the 2-stage manufacturing process also significant logistical advantages. So it is now possible to produce base plates in stock and then order-related coating and / or cut. Since the coating is no longer bound to the very long press times for the preparation of the base plate and thus comparatively fast coating methods can be used, can be estimated so far

Delivery times significantly undercut. Just-in-time delivery is comparatively easy to accomplish.

The process can be carried out both with the aid of cycle presses and with continuous presses.

It is known to use cyclically operating multi-day presses for the production of laminated panels. In these, a plurality of layers are always pressed with intermediate pressing plates in a press cycle. Usual pressing times are in the range of 100 minutes. However, in addition to the very high pressing time, the stacking up of the various layers and the provision of a plurality of press plates are also expensive. The use of tact presses is the only way to achieve higher plate thicknesses in the prior art. Continuous pressing methods, here usually isobaric double belt presses, are limited to plate thicknesses of a maximum of 1.2 mm due to the thus available, relatively short pressing time. However, according to the process of the invention, which permits elevated pressing temperatures, the pressing times are reduced, so that it is possible to produce a laminate with a thickness greater than 1.2 mm in a continuous pressing process. By the subsequent

Possibility of separate surface treatment, it is not necessary according to the inventive method to use an isobaric double belt press, which is already the case in the conventional laminate production to achieve a high-quality, closed laminate surface. Local differences in pressing pressure, unlike isochoric pressing in isobaric presses, would not result in undesirable fogging and irregular gloss. However, since according to the present invention, the coating takes place in a separate step and also a specific pretreatment such as grinding is still possible, for the first time an isochore double belt press can be used for the production of laminates. This allows a multiple press length, whereby the required pressing time can be guaranteed even with plate thicknesses of over 5, 12 or even 18 mm.

An additional advantage when using an isochronous double belt press with a length of at least 10 m, preferably over 20 m, particularly preferably over 25 m, lies in the variable temperature control. So it is possible with this type of press to provide different pressing temperatures in different zones. If now at the beginning of the press, the stratification is subjected to a high temperature, which is then reduced towards the end of the press, there is already a certain recooling effect, which reduces the internal vapor pressure in the plate to be produced and so in turn reduces the risk of plate bursts, the defining criterion for pressing time. This results in a further possibility to reduce the required pressing time for the production of a laminate plate.

Due to the fact that laminates can be produced by continuously operating double belt presses according to the inventive method for the first time, these are available for the first time in theoretically infinite length. By selectively cutting the produced plate strand after the double belt press plates can be produced for the first time with a thickness of 2 mm and more in almost any length. A restriction arises only by the local space conditions or the given

Transportation. Laminate plates with a length of more than 5 m, preferably more than 8 m, particularly preferably more than 10 m in length, can be produced for the first time.

The simple way to cut the plates to the dimensions mentioned, but also blanks with comparatively much reduced waste are possible because the cut to size after the press large format plates can already be selected with regard to the finished blank dimension of a later zuzuschneidenden plate. This results in an excellent format flexibility. In tact presses, this is not present, since here the manufacturable slab size is specified by the fixed size of the press surfaces.

As stated, the aim is to choose the pressing temperature as high as possible in order to reduce the pressing time. As favorable have temperatures above 155 ⁰ C, preferably above 185 ⁰ C, more preferably above 205 ⁰ C proved.

Due to the elevated pressing temperatures necessarily also increased pressing pressures. Thus, in comparison to the conventional pressure of about 8 to 10 MPa, those of at least 15 MPa, preferably of at least 19 MPa, more preferably of at least 23 MPa, have proved favorable.

As stated, as a result of the separate production step of the coating, in contrast to the prior art laminate production, no limitation is imposed on the application of a decorative paper impregnated with melamine resin. Rather, the 2-stage laminated panels can also be painted, printed, powder coated or provided with other decorative materials such as wood or stone veneer, decorative or metal foil or of course a decorative laminate. In addition, there is also the possibility of pressing with an impregnated decor paper available. Comparatively very good conditions are available with regard to the application of motifs by digital printing methods. Although these have already made inroads in the field of compact disk production, they are problematic because of the high heat required during compression, since the inks used for digital printing do not have the required heat resistance or only have an excessively expensive composition. A pretreatment of the base plate for subsequent coating may be required, but is by no means absolutely necessary. Performed coatings with decorative films of base plates without pretreatment have shown that when using, for example, 1-component reactive systems as an adhesive satisfactory composites can be achieved.

Furthermore, pressings impregnated with melamine resin have shown that with a grain size of 80 ground support plates with settings that are common in the coating of wood-based materials, can be well pressed. The achieved adhesion and its durability meets at least the requirements set for interior spaces. For direct coating with paints, system-based primers can be used to achieve high bond strengths.

In order to produce electrically conductive base plates, it is also possible to add corresponding additives to the impregnating resins. This makes it possible for the first time

Refining laminate panels with a powder coating.

There are the expert to various additives for

Selection. Most of these are based on metal salts or salts of organic acids.

According to one embodiment, in the coating step, it is also possible to apply a layer which makes it possible to use the coating at least in sections using solar technology. This is any utilization of the solar

Sun radiation by means of the coating meant. An example of solar technology usage is photovoltaics by means of solar cells. However, the present invention is not limited to this type of solar technology use.

As mentioned above, the object is also achieved by a corresponding laminate plate, wherein according to one embodiment, the base plate may contain at least one cellulose fiber web without impregnation, which forms in particular an outer side of the base plate. Alternatively or additionally, it is also possible to provide a coating in the form of a lacquer, a print, a powder coating, a decorative material and / or an impregnated decorative paper. The decorative material may be a wood or stone veneer, a decorative or metal foil or a laminate. The impregnated decorative paper can be impregnated in particular with melamine resin.

Likewise, the coating can be a coating which makes possible, at least in sections, solar technology use of the laminate plate. The latter can be formed for example by dye solar cells. Centerpiece of

Cells is an organic dye embedded in nanocrystalline electrodes of, for example, titanium dioxide. This converts the incident light into electricity.

There are now a large number of possibilities for designing and developing the method and the layered sheet according to the invention. For this purpose, on the one hand, reference is made to the claims subordinate to claim 1, on the other hand to the

Description of embodiments in conjunction with the drawing. Fig. 1 shows schematically the production of a compact plate (laminate plate 1) according to a possible embodiment of the method according to the invention.

For this purpose, a continuously operating, isochore double belt press 2 is provided here. For feeding the press 2, several rolls 3 of already impregnated kraft paper 4 are arranged in front of which the rolls 4a are unwound and fed directly to the press 2. In the present case, phenol resin-impregnated kraft paper 4 having a raw paper weight of 150 g / m ² and a degree of doctoring of 67%. At a residual moisture content of 7%, this corresponds to a basis weight of the impregnated kraft paper 4 of 270 g / m ² . The uppermost and lowermost layer is formed by a porous layer 5 of a plastic sheet 5a. The latter is removed after the press 2 again from the plate surfaces and again wound on a roll 3 'in order to be used repeatedly. In order to achieve higher plate thicknesses, in order to reduce the number of unwinding stations, a plurality of layers of impregnated paper webs 4a may be wound on a roll 3.

The press 2 has an effective length of 22.5 m and can be heated in sections by means of appropriate heating means 6 to different temperatures and also acted upon by respective press sections 7 with different pressing pressures. Thus, in the present case, the pressing pressure is selected in the first (front) of the press sections 7 with 20 MPa, which then reduced to about the middle of the press 2 to about 17 MPa and from there on is held. In the last quarter of the press length then no longer the pressing pressure is given, but it is controlled distance controlled, so given the distance of the press belts 8 in order to achieve the desired plate thickness as possible within the smallest tolerances.

The feed speed is approx. 0.55 m / min, which corresponds to a pressing time of approx. 41 minutes. With a plate thickness of 9 mm, this corresponds to a pressing factor, ie the ratio of pressing time and plate thickness, of about 4.5 min / mm.

After the press 2 a diagonal saw 9 is provided, which cuts the endless plate strand Ia to the desired plate length. The individual plates 1 are then cooled in a downstream (not shown) cooling star and can then be stored temporarily or be fed directly to further processing. As in the production of wood-based materials, it makes sense to grind the cooled plates 1 and then store them. The respective desired plate thicknesses can then be supplied to the order from the bearing of the coating.

Claims

claims

Anspruch [en] A process for producing a laminated board in which successively the following steps are performed: providing a plurality of ones

Impregnated cellulose fiber webs,

Forming a lamination by stacking the cellulose fiber webs provided with the impregnation, - introducing the lamination into a hot press,

Pressing the stratification while increasing the pressure and the temperature to a base plate,

- Extending the base plate from the hot press and

- Coating the base plate.

2. The method according to claim 1, characterized in that the cellulose fiber webs of the layering are all provided with the same impregnation.

3. The method according to claim 1 or 2, characterized in that the layering is provided with at least one cellulose fiber web without impregnation.

4. The method according to claim 3, characterized in that the layering is provided on one side and / or on both sides with an outer layer which is formed by at least one cellulose fiber web without impregnation.

5. The method according to any one of the preceding claims, characterized in that the provided with the impregnation cellulose fiber webs of the layering are all provided with a phenolic resin as impregnation.

6. The method according to any one of the preceding claims, characterized in that one or more of the cellulose fiber webs provided with the impregnation are provided with an impregnation containing electrically conductive additives, in particular salts of organic acids, preferably metal salts.

A method according to any one of the preceding claims, characterized in that between the step of extending the base plate from the hot press and the step of coating the base plate, a step of pretreating the base plate is performed.

8. The method according to claim 7, characterized in that the pretreatment comprises grinding, smoothing, in particular thermal quenching, the base plate and / or applying primers, primers and / or primers on the base plate and / or a plasma treatment of the surfaces of the base plate.

9. The method according to any one of the preceding claims, characterized in that in the step of compressing the stratification, the temperature is increased to at least 155 ° C, in particular at least 185 ° C and preferably at least 205 ⁰ C, in particular the temperature during the pressing time varies, in particular decreases.

10. The method according to any one of the preceding claims, characterized in that in the step of pressing the

Stratification of the pressure to at least 15 MPa, in particular at least 19 MPa and preferably at least 23 MPa is increased, in particular, the pressure during the pressing time varies, in particular reduced, is.

A method according to any one of the preceding claims, characterized in that, prior to the step of compression, a layer of water vapor permeability is provided adjacent to one or both sides of the lamination.

12. The method according to claim 11, characterized in that the water vapor-permeable layer is removed after the step of pressing from the base plate.

13. The method according to claim 11 or 12, characterized in that the water vapor-permeable layer is a particular porous layer of a non-woven or a film, in particular of a plastic.

14. The method according to any one of the preceding claims, characterized in that the hot press is a continuously operating press.

15. The method according to claim 14, characterized in that the continuously operating press a

Double belt press, in particular an isochore double belt press is.

16. The method according to claim 14 or 15, characterized in that the continuously operating press has a press length of at least 10 m, in particular at least 20 m, preferably at least 25 m.

17. The method according to any one of the preceding claims, characterized in that the extending out of the hot press base plate is a continuous plate strand, are produced from the cut to length by single plates.

18. The method according to any one of the preceding claims, characterized in that the step of coating a painting, a printing, a powder coating, an application of a decorative material, in particular a wood or stone veneer, a decorative or metal foil or a laminate, and / or pressing with an impregnated, in particular impregnated with melamine resin, decorative paper comprises.

19. The method according to claim 18, characterized in that in the step of coating, a layer is applied, which allows at least partially solar technology use of the coating.

20. Laminate plate, in particular produced by a method according to one of the preceding claims, containing

- A base plate having a plurality of provided with an impregnation, stacked and pressed under increased pressure and elevated temperature cellulose fiber webs and - A provided on at least one side of the base plate coating.

21. Laminate according to claim 20, characterized in that the base plate contains at least one cellulosic fiber web without impregnation, which forms in particular an outer side of the base plate.

22. Laminate board according to claim 20 or 21, characterized in that the thickness of the layered sheet at least 2 mm, in particular at least 5 mm, preferably at least 12 mm and more preferably at least 18mm, and / or the length of the laminate plate at least 5 m, in particular at least 8 m and preferably at least 10 m.

23. Laminate according to one of claims 20 to 22, characterized in that the coating is a lacquer, a print, a powder coating, a decorative material, in particular a wood or stone veneer, a decor or metal foil or a laminate, and / or an impregnated, in particular with melamine resin impregnated decorative paper.

24. Laminate according to one of claims 20 to 23, characterized in that the coating is an at least partially solar technology use of the laminate plate enabling coating and preferably has dye solar cells.