DE2858182C2 - - Google Patents

Description

The invention relates to a decorative sheet for the production of decorative panels with high abrasion resistance.

High-pressure decorative panels are usually made so that you get a variety of with different synthetic thermosetting ones Resins impregnated paper layers stacked and cures under heat and pressure. Usually there is one such arrangement seen from below from a number, for example three to eight, core arches impregnated with phenolic resin Kraft paper over which a melamine resin-impregnated printing or decal sheet is located. Above the decal sheet is a Overlay, which is almost transparent in the finished laminate and to protect the decal sheet.

The sheets used for the core layer are made of kraft paper from mostly 66.4 to 92.3 g / m² Ream weight (weight per 500 sheets Paper with a sheet size of 60.9 × 91.4 cm).  

Before stacking the kraft paper with a aqueous-alcoholic phenol-formaldehyde-Resolharzlösung impregnated, dried, partially cured in a hot air oven and then cut into sheets. The printed bow is a pigment filled high quality alpha cellulose paper of 37 to 93 g / m², which is mixed with an aqueous-alcoholic melamine Formaldehyde resin solution impregnated, dried, partially cured and then cut into leaves. The sheet was before impregnating with the resin, with a decoration pattern or with a gravure reproduction of natural materials such as Wood, marble, leather printed.

An overlay is used regularly if the decor or Press sheet has a surface pressure in order to reduce the pressure to protect against abrasion. The overlay is an alpha cellulose paper high quality of about 17 to 22 g / m², with melamine Formaldehyde resin in a manner similar to the printed or decal sheet, hereinafter simply referred to as a decal sheet, impregnated is, if not a larger amount of resin per unit weight Paper is used. The individual bows are as above indicated stacked and when impregnated six Core arches are used, obtained by hot pressing a laminate having a thickness of about 1.25 mm, wherein It should be noted that a different number of sheets Can be used to make thicker or thinner laminates  manufacture.

For Heißverpressung the above-described stack between given polished steel plates and at a temperature of 110 to 170 ° C, z. B. 150 ° C, a pressure of 56-112 kg / cm², z. B. 70 kg / cm², subjected to solidification of the laminate and for curing the resins (about 25 minutes). The resin flows doing so in the paper sheets, is cured and the bows become a laminate unit, i. H. a high-pressure Decorative panel, solidified. Two such stacks can be back to back separated by a release layer, pressed, causing it it is possible to obtain by separation two laminates. Frequently becomes a stack, with an Al foil-coated kraft paper between overlay and metal plate, with the aluminum side to the Overlay, hot pressed to obtain a laminate that a lower gloss and a surface with a light structure as is desirable for some products.

The backs of the finished laminates are then sanded, for gluing with panels, plywood or other substrates to enable. The glued, with a laminate surface provided panels, then in furniture, covers, work surfaces in kitchens, for table covers, business facilities and processed for other end uses, taking them because of the combination of appearance, durability and economy one have found wider use.

It is known to modify the method described above in many ways,  for special effects in appearance and in the structure to obtain. There may be other cure cycles and others Resin systems are used.

In addition to high-pressure decorative panels, there are also low-pressure products, including low-pressure laminates, the other saturated Polyester resins or melamine-formaldehyde resins use. On major product is the low-pressure melamine plate, which is usually only at about 12 to 15 kg / cm² and 160-175 ° C pressed is. Although cheaper, these products do not satisfy the strict standard provisions for high pressure decorative panels of the National Electric Manufacturers Association, NEMA LD3-1975. These standard regulations mainly concern abrasion, resistance against stains, against heat, against shock as well Dimensional stability.

One property of particular importance is resilience against abrasion. A high-pressure decorative panel must be sufficient Abrasion resistant to heavily used surfaces to be used like covers of "dinette" surfaces, Control marks. The standard NEMA abrasion resistance test is the "NEMA test LD-3.01". This will be a Laminate sample mounted on a rotating disk, on the two rubber wheels under load are running on their Have front side calibrated sandpaper strips. During the Runs the sandpaper in the running area under abrasion the Surface of the laminate, through the overlay from, until  the printed pattern is exposed and destroyed. The NEMA standard regulations for laminates class I require that at the laminate after 400 revolutions not more than 50% of Decor is destroyed. The 50% end point is determined by that one forms the means of the number of revolutions, at where the decor shows an initial abrasion and the number of Turns where the decor is completely destroyed.

For a standard high-pressure decorative panel with 35-40% resin content in the decal sheet, but without overlay the abrasion resistance only about 50 to 75 revolutions. If special Melamine resins and resin contents of 50 to 55% for the decal sheet are used, without overlay, abrasion resistance occasionally reach up to about 150-200 turns. It However, the laminates tend to surface hairline cracks. In addition, they are difficult to produce because it is difficult to the sheet to be uniformly impregnated; In addition, they do not fulfill the minimum of 400 required by NEMA regulations Revolutions.

Nevertheless, it is desirable to produce a laminate which is independent of an overlay and especially one Abrasion resistance of 400 turns. It continues desirable to have available a laminate which In addition to an abrasion resistance of 400 revolutions an initial abrasion point which is at least equal to the initial abrasion point a conventional high pressure laminate with overlay,  typically from 175 to 200 revolutions. This is why desirable because the appearance of the laminate for the Practice is unsatisfactory, not only if 50% of the pattern, but even if a much lower percentage is destroyed is. Many years of experience shows that conventional laminates with overlay, which has a starting abrasion point of 175-200 Circuits have when used for heavily used surfaces are still used during normal periods of use have a satisfactory appearance, it being understood that that the replacement of most laminates in the usual uses more for reasons of style than because of the abrasion of the Pattern occurs. A laminate without overlay should thereafter both a NEMA abrasion resistance of at least 400 turns and an initial abrasion point of at least 175-200 revolutions even if this last request made not part of the NEMA standard.

It is desirable for a variety of reasons, laminates, regardless of overlays, lending these properties because the overlays significantly increase the material costs, including both the paper costs as such as well as the costs of impregnation of the overlay used in the resin and the cost Processing and handling losses include. In addition, deteriorates an overlay as an intermediate layer of noticeable strength between Decal sheet and the eye of the beholder felt the clarity of the decoration pattern. Although the cellulose fibers of the overlay have a refractive index close to that of the cured melamine  Formaldehyde resin is and are barely recognizable. Allow it However, the modern printing process very accurate reproductions of natural materials, in particular of different ones Plywood species. Because these printed reproductions To achieve the appearance of natural veneers is through the overlay caused slight haze or blur visually disturbing and destroys much of the desired reality.

Finally, the overlay contributes to the committee enlargement of Laminates at. The impregnated, dried overlay tends because of static charge to attract small dirt particles. This dirt is difficult to detect and heavy removable and leads to faulty laminates. The impregnated dried overlays are also brittle, are heavy manageable and fragments occasionally fall under the surface of the overlay with the result of faulty plates. Farther have overlay-containing laminates, in particular such with a relatively high surface gloss, the inclination, very quickly dull, even if only moderate abrasion be subjected.

The problem, laminates improved abrasion resistance lend, its long. Despite many attempts it was previously not possible to produce a laminate without Overlay a NEMA abrasion resistance of at least 400 turns and a starting abrasion point in the same investigation of at least 175 to 200 turns.  

It is well known that small, hard mineral particles, which are fine in the overlay or in resin mixtures for the coating of the decal sheet are distributed, the abrasion resistance of high pressure laminates can improve (see, for example, the US patents 31 35 643, 33 73 071 and 33 73 070). In these methods is either an overlay is mandatory or it will become one created another form of overlay and associated resin. Next z. For example, in US Patent 31 23 515 the overlay impregnated with a finely divided frit and then as usual arranged above the decal sheet. After the US patent 37 98 111 are small mineral particles, preferably aluminum oxide, during papermaking in the area of introduced upper layer of the paper. Experiments have shown that produced with the then printed paper, without overlay Laminates initial abrasion values of less than 100 revolutions, some even only 35 revolutions. In addition, show in a rubbing test such laminates decor destruction after only 3000 friction cycles, so are useless. satisfactory Nor could solutions be found in US Pat. Nos. 3,445,327, 39 28 706 and 36 61 673, even less the US patents 32 59 537, 31 57 518, 37 16 440, 39 46 137 and 33 18 760. Next it is from the German design 12 63 205, the German Utility Model 18 23 679 and the Published documents of the German patent application R 5324 IVc / 22h (published 03/31/1955, corresponds to US-PS 31 65 643) known in the manufacture of laminates together with the thermosetting Paper impregnating resins finely ground or colloidal silicic acid then to dry the paper and in the usual way  to produce the laminates by hot pressing. On too In this way, laminates are satisfactory abrasion resistance unavailable.

The invention relates to decorative webs for the production of multi-layer decorative panels with improved abrasion resistant Surface with a decoration on a substrate Paper layer according to claim 1. Advantageous embodiments thereof are the subject matter of claims 2 to 6. This particular high-pressure decorative panels accessible, which is also independent of an overlay, the claims comply with NEMA abrasion regulations, and moreover an initial abrasion point of at least 175-200 revolutions having. The invention therefore also the use a decorative sheet according to the invention for the production of decorative panels and decorative laminates.

A decorative sheet according to the invention is available, by putting a wet thin layer of a mixture made of abrasion resistant, finely divided, mineral material and a binder therefor, which in the dry state for  thermosetting paper impregnating resin permeable, with this compatible and under impregnation and coating conditions is stable, applying to the paper layer and the Layer dries.

In a preferred embodiment, the decorative sheet is then still with a heat-curable polyester or melamine-formaldehyde Resin impregnated.

The whole or essentially the whole abrasion-resistant, finely divided, mineral material is deposited on the surface. As a binder, microcrystalline cellulose z. B. especially proven with a content of sodium carboxymethylcellulose. The drying is usually at a temperature of at least 80 ° C made.

It has proven to be particularly favorable if, as abrasion-resistant, finely divided, mineral material alumina a particle size of 20 microns to 50 microns used. The ultrathin In particular, the coating is 0.0005 to 0.0075 mm thick.

For example, the coatings can be 5-10 parts by weight microcrystalline Cellulose to 20-120 parts by weight of alumina. In addition, nonionic wetting agents may be included. Particularly good results are achieved when the thin layer an addition of organosilane, in particular about 0.5 to about 2% by weight Organo-aminosilane, based on the weight of the alumina,  contains.

The decorative webs are inventively especially for the production of multi-layer decorative panels in a conventional manner used under heat and pressure.

Using a decorative sheet according to the invention can be a layered construction Make decorative panel of high abrasion resistance, with pad and on it arranged, heat-cured impregnating resin containing Decorative layer, wherein the decorative layer at its top over the Decor has an ultra-thin abrasion resistant layer, the an abrasion-resistant, finely divided mineral and a binder for this mineral containing the heat-cured impregnating resin the decorative layer is compatible and the clarity not affected, being the ultra-thin abrasion resistant Layer forms the topmost layer of the decorative panel.

In particular, it is such a decorative plate with Underlay and decorative layer, which is available by clicking on the decorative layer, before impregnation with the thermosetting Resin, a wet thin layer of a mixture of abrasion resistant, finely divided, mineral material and a Binder therefor, in the dry state for the thermosetting Impregnating resin permeable to this compatible and under impregnation and coating conditions is stable, apply, the thin layer dries and first then the impregnation and hot pressing together with the pad performs in a known manner.  

The preferred thermosetting resin is melamine-formaldehyde resin, the preferred binder is microcrystalline cellulose, e.g. B. also together with sodium carboxymethylcellulose. As finely divided Mineral is especially alumina, especially one Particle size of 20 to 50 microns included. Preferably the ultra-thin coating has a thickness of .0013 to 0.0075 mm.

Have proven particularly high-pressure decorative panels, the Base a variety of phenolic resin-impregnated paper layers comprises, the decorative layer impregnated with a melamine resin Paper layer is the abrasion resistant fine particulate mineral Alumina having a particle size of 20 to 50 μm, the binder is microcrystalline cellulose and the starch the coating is about 0.0013 to 0.0075 mm.

Often in the abrasion-resistant layer is still an organosilane, in particular organo-aminosilane.

The invention will be explained in more detail below in connection with drawings, in which

Fig. 1 is a schematic cross section showing a decorative sheet according to the invention, and

Fig. 2 is a schematic cross section showing a decorative plate produced according to the invention.

The invention is based on the development of a preparation, which contains small mineral particles and which, when coated, without resin, a non-impregnated, printed pattern Gives paper surprising and unexpected properties, so that such a paper for the production of decorative plates can be used and the resulting laminates, even without overlay, highly abrasion resistant are. In its preferred form is the coating formulation composed of a mixture of small alumina particles and a smaller amount of microcrystalline cellulose particles, both in a stable, aqueous slurry are dispersed. The alumina particles of such small size are that they do not have the visual effects of Endprodukt affect, serve as abrasion resistant material and the microcrystalline cellulose particles serve as preferred binder. The binder must be compatible with the resin used later in the lamination process should be, usually a melamine resin or in the case of certain Low pressure laminates, a polyester resin. The microcrystalline Cellulose performs this function as well as it does also the small aluminum oxide particles on the surface of the Paper layer stabilized.

According to FIG. 1, a conventional, unimpregnated, patterned or decorative paper is coated with the mixture of hard mineral particles and binders, preferably aluminum oxide and microcrystalline cellulose particles, and the coating is coated at an elevated temperature, e.g. In a hot air oven, dried to form a thin coating of thickness of only 0.0005 to 0.008 mm. The resulting abrasion-resistant, coated paper is then impregnated with melamine or polyester resin and dried in a conventional manner. Such a decorative sheet is then ready for laminate production.

Referring to FIG. 2, the resin impregnated decorative sheet, arranged with the ultra-thin, abrasion-resistant coating on its surface, in a manner conventional for multi-layer decorative panels manner without an overlay would be required. The stack is then cured under heat and pressure in the usual manner to form the decorative panel. A surprising feature of the ultrathin coating is that, while being very thin, it can provide the decorative panel with abrasion resistance that not only complies with NEMA standard requirements of 400 turns, but also achieves an initial abrasion point of 175 to 200 turns in this process arrangement ,

It is also surprising that the coating firmly on the Surface of the print sheet even with a later melamine resin Impregnation adheres without significant amounts of mineral particles in the impregnating solution to loss or from migrate to the surface of the paper. Another surprising Property of this coating is that they penetrate the melamine-formaldehyde resin solution into the interior of the Paper during the impregnation stage does not seem to prevent.  

Such intrusion is essential, otherwise the decor sheet, What can not be, can starve, for example, in her Center, and thus possibly after pressing one Layer separation or delamination could occur. A Another desirable feature of the coating consists in that they are not substantially light-scattering or light-attenuating works, but that you have a very clear, hard pattern obtained in the decorative panel.

Without adhering to the following theoretical considerations, It is believed that the improved properties of the invention occur as follows: microcrystalline cellulose particles have very large external forces, which bind to others cause polar substances such as cellulose and alumina. Therefore, an aqueous slurry of microcrystalline Cellulose and alumina stable and does not settle quickly, even if the aluminum particles are not in water are stable. It also binds when this slurry applied to the paper, the microcrystalline cellulose apparently the alumina particles to the surface fibers of the paper and to the surface of the printed pattern and thereby avoids the migration of the alumina particles under the surface. This should lead to the good abrasion resistance contribute by such small amounts of alumina is reached. It therefore remains all or substantially all aluminum oxide particles on the surface back, where they have the greatest effect, rather than below the surface  to be dispersed, where they only relatively little to the initial abrasion resistance could contribute.

As already mentioned, the coating is preferred Slurry preparation a mixture of small particles of Alumina and a smaller amount of microcrystalline Cellulose particles, both of which are dispersed in water. It must of course have a sufficient amount of small mineral particles be present so that the product obtained the desired Has abrasion resistance and it must be sufficient Amount of binder may be present to the mineral particles to hold the surface of the sheet. In general, be satisfactory results achieved with about 5 to 10 parts by weight microcrystalline cellulose to about 20 to 120 parts by weight Aluminum oxide, if it is possible, of course, outside to work in these areas. The amount of water in the slurry is also determined by practical considerations, because if too little water is available, the mud is so thick it will be hard to apply; if too much water is present, the slurry is so thin that it because of Running is difficult, a consistent strength of To obtain coating.

The preparation used for the coating also contains preferably a small amount of wetting agent, preferably a nonionic surfactant and an organosilane. The amount Wetting agents are not critical, but are very low  Quantities desirable. Excess quantities bring no advantage. When an organosilane is used, it acts as Coupling agent containing the alumina particles with the melamine Matrix chemically binds and impregnates after impregnation and curing provides a better initial abrasion resistance because the alumina particles chemically with the melamine resin in addition to are bound to the mechanical bond and therefore longer stationary remain under abrasion conditions. That in the coating contained organosilane should be selected from a group Be it used with the particular thermosetting Making resin compatible with laminate production; in this Respects are organosilanes with an amino group, such as gamma Aminopropyltrimethoxysilane, particularly effective for use with melamine resins. The amount of organosilane used must not be big, and it is even 0.5%, based on the Weight of alumina, effective to the abrasion resistance improve the final laminate; as a maximum amount about 2% by weight, based on the weight of the aluminum oxide, where larger quantities are not too much better Results.

The coating using microcrystalline cellulose as a binder, especially at elevated temperature, dried before the sheet is impregnated with the melamine resin becomes. As lower drying temperature have about 82 ° C proven, the preferred drying temperatures in Range of 115 to 135 ° C lie.  

In terms of abrasion resistant mineral particles is Alumina is the preferred material. Silica, the in certain prior art patents as well is provided as abrasion resistant material does not deliver the best results like alumina. Other minerals with sufficient hardness, such as zirconium oxide, cerium oxide, diamond dust, can be used, but are expensive or sometimes lead to color deviations. Silicon carbide was also investigated and provides good abrasion resistance as well strong color change.

The size of the aluminum oxide particles must also be taken into account. Under 20 microns particle size, the abrasion resistance is low and the preferred minimum particle size is about 25 microns. Up the particle size is limited by the surface roughness and by visual impairment. The preferred maximum size the alumina particle is about 50 μm.

Of all the binders tested is microcrystalline Cellulose particularly preferred. The binder does not just have to the mineral particles are stationary on the surface of the sheet but should also be used as a suspending agent in the slurry what then an additional suspending agent makes superfluous. Microcrystalline cellulose is both a suspending binder as well as a film former, not water soluble and forms a highly porous film through which can penetrate the thermosetting resin. The binder must  furthermore, with the impregnating resin for decorative board production be compatible. Microcrystalline cellulose is both with Melamine resin as well as compatible with polyester resins. Farther the binder may be present in the layer thickness present in the laminate Do not break or weaken the light. microcrystalline Cellulose is also satisfactory in this regard.

Other binders that may be included are different typical suspending binders, such as anionic acrylic polymer, Carboxymethylcellulose and similar materials, such as hydroxypropylcellulose, methylcellulose, polyvinyl alcohol, Polyvinylpyrrolidone. However, microcrystalline cellulose is the preferred binder.

Microcrystalline cellulose is non-fibrous cellulose, at the cell walls of the cellulose fibers into fragments in lengths in the range of a few microns to a few tenths of a micron are broken. It is a purified alpha-cellulose. microcrystalline Cellulose is a white, odorless, hygroscopic Powders, their preparation in the US patent 32 75 580 is described. It is water dispersible and contains about 11% sodium carboxymethyl cellulose as a protective colloid. The particle size is less than 0.1% on a sieve with a clear mesh of 0.25 mm.

Preferably, the coating is obtained by firstly a mixture of alumina particles and microcrystalline  Cellulose from aqueous slurry on a non-impregnated Applied sheet, at elevated temperature of at least 80 ° C dries to form a coating in a thickness of 0.0005 to 0.005 mm. Then the decor sheet impregnated with thermosetting resin in a conventional manner become. The ultra-thin layer thus formed provides an unexpected high abrasion resistance.

The desired properties of the binder, as in particular of microcrystalline cellulose are: It acts as a film former and binder for the mineral particles. It acts as a suspending agent in the slurry for the mineral particles and will during the subsequent Impregnation process with the thermosetting resin not washed out. It is compatible with thermosetting resins, such as Melamine resin or polyester resin and penetrable for this. It is heat resistant compared to the laminate production applied heat and it does not lead to a refraction of light or mitigation.

The following examples serve to illustrate.

Example 1

Microcrystalline cellulose is added to water with stirring a Waring mixer. After 2 to 3 minutes in the mixer is the cellulose is completely dispersed and becomes alumina moderately stirred. Finally, you give 3 drops of a non-  ionic surfactant to promote wetting.

The resulting slurry is applied as a coating an unimpregnated patterned sheet of 106 g / m² Ream Weight (weight per 500 sheets of paper with a sheet size of 60.9 × 91.4 cm) with a wood structure surface pressure. The coating is dried 3 minutes at 130 ° C. Then you saturate the paper normally using melamine-formaldehyde resin and dries as usual. The resin content is 45 to 48% and the volatile content is 5 to 6%. Man forms then a stack and pressed it in a known manner about 25 minutes at about 149 ° C and 70 kg / cm².

The formulations and abrasion results are given below a wet coating of 0.038 mm, the calculated a dry coating with a thickness of 0.0038 mm results.  

Table I

From the comparative investigations given above, it can be seen that that the microcrystalline cellulose as such is not satisfactory (experiment 2) and that the use of alumina with over 20 μm average particle size satisfactory Initial abrasion, as well as NEMA abrasion resistance values and with 30 and 40 μm average particle size optimal  Delivers results. Furthermore, the laminates had a clearer decor than laminates with overlay and they match also the other NEMA durability requirements.

example 2

Prepare 4 slurries as in Example 1, Run # 3. Each is used to produce a 0.0762 mm thick wet coating on non-impregnated paper (106 g / m 2) and dried as in Example 1 to give a dry coverage of about 0.0076 mm. The dried paper is impregnated with melamine resin and produces an arrangement as shown in FIG . The laminate is produced as described in Example 1. The only change in the four trials is the average particle size of the alumina. The following results are obtained:

Table II

example 3

Example 2 is repeated in three experiments, wherein in each Trap alumina particles with an average particle size of 40 microns are used. The only change exists in the strength of wet coating. You compare that Laminates as in Example 2. The results are:

Thickness of wet coating (in mm) Decor destruction at 500 revolutions 0.0762 (0.0076 dry) | 1% 0.0508 (0.0051 dry) 10% 0.0254 (0.0025 dry) 30%

example 4

The procedure of Example 1 is repeated, using as Coating slurry for the printing sheet the following Preparation used:

250 ml of water
7.5 g of microcrystalline cellulose
60 g of alumina, average particle size 40 μm, and
1 drop of nonionic surfactant.

Two experiments are carried out with the formation of wet strengths of 0.025 or 0.0508 mm. After laminating the show  Abrasion tests no destruction of the decor at 500 Revolutions.

example 5

The procedure of Example 4 is repeated using the same Coating preparation used except that 120 g Aluminum oxide with an average particle size of 30 microns used. There are three experiments with wet coatings one Strength of 0.013 or 0.025, or 0.038 mm performed. you obtains the following results in terms of abrasion resistance of the laminate after 500 revolutions:

0.013 mm (0.0013 mm, dry) 10% decor destruction 0.025 mm (0.0025 mm, dry) <1% decor destruction 0.038 mm (0.0038 mm, dry) <1% decor destruction

The three laminates were fully satisfactory in every respect. They showed good machinability without Splintering or chipping.

The physical properties of the third plate (manufactured with paper of a dry coating thickness of 0.0025 mm), studied according to the NEMA standard LD3-1975 Impregnating and pressing are:  

Abrasion resistance <500 revolutions Resistance to staining no stain effect moisture absorption 6.5% Swelling of the center 8.9% Blow (unsupported) 36 ° Radiant heat (unsupported) 185 seconds Hot water no effect Hot wax no effect dimensional stability M.D. 0.24%, C.D. 0.56%

These are overall satisfactory or superior values.

example 6

Example 4 is repeated in two experiments using the same preparation, except that in the first experiment 60 g of silicon carbide with a particle size of 27 microns instead of alumina and in the second trial 60 g of silicon carbide a particle size of 10 microns instead of alumina be used. With every preparation the coatings become in a thickness of 0.013 mm, or 0.025 mm, or Deposited 0.038 mm. The sheet has one in general "gray" or cloudy color as a result of the color of silicon carbide. The following results are obtained:  

Table VI

From the table it can be seen that, although the abrasion Resistance is satisfactory, the silicon carbide 10 μm thick gives lower results than silicon carbide with 27 μm thickness. The bad color can only at certain colors of the sheet are tolerated.

example 7

Example 4 is repeated with three preparations, wherein but instead of alumina particles 60 g of glass beads with a particle size smaller than a sieve of a light Mesh size of 0.044 or 240 g of such glass beads or 60 g silica aerosil one micron particle size used. Each preparation is made with a standard of 0.013 mm, 0.025 mm and 0.038 mm, respectively. You get the following results:  

kind Decor completely worn 60 g glass 200 turns 240 g of glass 200 turns 60 g silica aerosil <100 revolutions

None of these samples provides satisfactory abrasion resistance ability.

example 8

The procedure of Example 4 is repeated, except that the Coating preparation modified in a first sample by that 6 g of anionic acrylic polymer is used as binder and in the second sample, 9 g of carboxymethylcellulose, respectively used instead of microcrystalline cellulose. The two Samples show about 5% in the NEMA study Abrasion at 500 revolutions, a satisfactory behavior. However, the anionic acrylic polymer easily causes one milky appearance in the laminate, from which results that this material is satisfactory only for certain colors can be used. The laminate in which carboxylmethylcellulose used as a binder for alumina, has lower resistance in boiling water and fulfilled not the NEMA standard regulations in this regard; this material can only lower as a low pressure laminate Quality to be used.  

example 9

To study the effects of organosilanes, the following procedures are performed. 1 g of gamma-amino is dispersed propyltrimethoxysilane in methanol containing 10% water. A small amount is used to wet the alumina powder. This dispersion is then added to 100 g of alumina a particle size of 30 microns and mixed with the alumina the solution until thoroughly wet. It is then dried Alumina. Example 4 is repeated, except that one the coating of the printing sheet with a wet thickness of 0.0063 mm (dried 0.00063 mm). One compares the received one Laminate with laminates, corresponding to Example 4 (without the organosilane), but also in a standard of 0.0063 mm are made. All laminates are pressed on Mirror shine. In the following Table VIII are the results the abrasion resistance tests stated:

Table VIII

From the results it can be seen that the organosilane quality the abrasion resistant coating improved.  

example 10

It was the efficiency of the process in terms of a Evaluation of low-pressure plates investigated. Man poses a slurry as in Example 1 with 250 g of water, 6.5 g microcrystalline cellulose, 30 g of alumina with a particle size of 30 μm and 2 drops of a nonionic surfactant ago. The slurry is worn with a standard thickness of 0.0125 mm (dry 0.00125 mm) on unimpregnated, printed Decor paper and dry for 3 minutes at 126 ° C. you then impregnate the sheet and dry twice to complete To ensure impregnation. The impregnated bow then pressed with a plate of wood particles with 14 g / cm² at 149 ° C 6 minutes. For comparison, you put an identical Low-pressure laminate, but without abrasion-resistant coating on the surface of the sheet, ago. Both samples subjecting to the NEMA abrasion test, the following Results are obtained:

Table IX

From the investigations, as indicated in Table IX, it can be seen that that the invention also greatly improves the abrasion resistance improved by low pressure laminates.  

example 11

Repeat the procedure of Example 9 and carry a Coating with a thickness of 0.038 mm (dry 0.0038 mm). Perform four experiments, the amount of organosilane is changed and subjects the obtained laminate the NEMA abrasion test. Furthermore, you put the Initial abrasion, with the results of Table X. are removed.

Organosilane amount g / 100 g of alumina Initial abrasion, turns 0 175 2 475 3 510 6 400

The previous investigations show that the effect of the Organosilane, after reaching an amount of about 2 wt .-%, based on the weight of the alumina, not essential is improved; and actually were, among the special ones Conditions, at 6% organosilane the results worse than at 2%, but still much better than without Organosilane.

example 12

Repeat the procedure of Example 11 for the beginning  Abrasion resistance of the laminate as a function the temperature used to dry the applied on the sheet Layer is used to determine. To this end Coating the decal sheet with the coating preparation of Example 4 in a ratio of 13-17 g / m² (dry 0.005 mm), the coating preparation corresponding to silane Example 9 contains. The coating of each sample is dried 3 minutes at different temperatures, as in Table XI specified. After drying, the coated air is conditioned Arc at 50% relative humidity and 21 ° C. Man impregnated then the sheets in the usual way with melamine-formaldehyde resin and then sets the laminate in the usual way with a matted pressing tool ago. The following results are obtained:

Oven temperature, ° C Initial abrasion, turns 71 225 82 550 93 550 115 575 129 575

example 13

Make a slurry of the ingredients as in Example 1 described, forth, to what you 6.5 g parts by weight microcrystalline Cellulose, 2 parts by weight of carboxymethylcellulose, 30 parts  Alumina (30 microns) and 250 parts by weight of water used. Furthermore, one uses a nonionic surfactant in low Amounts.

The resulting slurry is applied to the printing sheet using a Meyer bar coater, so that a dry thickness of 0.0038 mm is achieved. The sheet is then impregnated with melamine-formaldehyde resin to a resin content of 41.7% and dries to a volatile content Components of 4.2%. You then press the stack with the Coated sheet in a known manner to a mirror finish Laminated board.

This laminate is compared with one in the usual way using a 15g / m² overlay high gloss laminate, what to do with the two laminates below described "dose rub test" subjects. The inventive Laminate has an initial abrasion of 325 turns and a NEMA abrasion value of 1021 turns. The comparison results after the "canned rub test" are:  

Table XII

Destruction of the print pattern starts at both samples about 30 000 revolutions, but it can be seen that the conventional laminate increasing surface matting already at only 1500 friction revolutions, and that actually the surface matting almost at first a few hundred frictional turns begins. Furthermore, the conventional Laminate already completely frosted before the Decoration destruction begins (30 000 rubbing cycles).

The can rub test simulates wear as it does with a fiberglass tray when moving back and forth on a Laminate is produced. One corresponding to a fiberglass tray Part is attached to the bottom of a can (# 10), which in turn is burdened with 2.26 kg weight and flexible  connected to a cam-controlled receiving device, the one back and forth movement with an amplitude of 12.6 cm causes.

The results obtained show the present method as a revolutionary development in the field of decorative panels out. It is the first time a laminate accessible, the even without overlay both the NEMA abrasion resistance of at least 400 revolutions as well as an initial abrasion value, at the same examination, of at least 175-200 Revolutions reached.

There are many uses for laminates in which the initial wear value rather than the NEMA abrasion value is the service life the surface determined. Examples are control tables in supermarkets, counters at food service, Coffee-casks and other commercial surfaces, that of the scouring effect and the gliding of unglazed ones Dishes, cans, fiberglass trays are exposed. If small areas of the decor after a relatively short period of use start to disappear, especially in an irregular one Pattern, the surface becomes unreasonable and expensive for the owner Replacement necessary. When the surface is gradually uniformly over a long period of time the wear period is normal due to style changes conditional period of about 3 to 5 years.

Claims (7)

A decorative sheet for producing high abrasion resistance decorative panels having a decor on a paper layer serving as a substrate, characterized by an ultra-thin abrasion resistant coating over the decor comprising an abrasion resistant fine mineral in an amount sufficient to form an abrasion resistant layer without sacrificing clarity , and a binder for this mineral in an amount sufficient to bind it to the surface of the paper layer, and the binder is compatible with and permeable to these resins with thermosetting melamine-formaldehyde and / or polyester resin used for decorative board production. 2. decor sheet according to claim 1, characterized in that it additionally with a thermosetting polyester resin or melamine-formaldehyde resin impregnated. 3. decorative web according to one of the preceding claims, characterized characterized in that the binder is microcrystalline cellulose. 4. decorative sheet according to one of the preceding claims, characterized characterized in that the abrasion resistant mineral comprises alumina Particle size of 20 to 50 microns.   5. decorative web according to one of the preceding claims, characterized characterized in that it is impregnated with melamine resin which is abrasion resistant Mineral alumina with a particle size of 20 to 50 microns, is contained as a binder microcrystalline cellulose and the ultra-thin coating has a thickness of 0.0005 to 0.0075 mm having. 6. decorative web according to one of the preceding claims, characterized characterized in that the coating further comprises an organosilane, in particular from 0.5 to 2.0 percent by weight of organo-aminosilane, based on the Weight of alumina, contains. 7. Use of a decorative sheet according to one of claims 1 to 6 for Production of decorative panels and decorative laminates.