DE102010050141A1 - Producing overlay useful e.g. for laminate, comprises e.g. unrolling overlay-base paper from roll to form recoverable paper web, and applying dispersion of resin and fine hard particles, on both sides of paper web, and continuously drying - Google Patents

Abstract

Producing overlay, preferably for laminates, comprises: unrolling an overlay-base paper from a roll to form a recoverable paper web (6); applying a dispersion made of resin and fine hard particles, on both the sides of the paper web by wet-on-wet coating method, and proportioning the application; applying a dispersion made of resin and coarse hard particles, on one side of the paper web by wet-on-wet coating method, and proportioning the application; and continuously drying the paper web in a single step in a drying channel. Independent claims are also included for: (1) an overlay comprising a base paper, respectively a layer made of a resin with dispersed fine hard particles, present on each side of the base paper, and an outward subsequent layer made of a resin with dispersed coarse hard particles, present on one of the two sides of the base paper; and (2) a laminate flooring board comprising a carrier material made of a fiber- or wood material, and the above overlay.

Description

TECHNICAL AREA

The invention relates to a method for producing an abrasion-resistant and abrasion-resistant overlay, in particular for coating purposes and for laminates, as well as an overlay produced by this method.

BACKGROUND OF THE INVENTION

In the manufacture of floor laminates, overlay papers are often placed on a decorative layer to produce a highly transparent and at the same time highly abrasion and abrasion resistant surface which has high chemical resistance and water resistance and protects the decorative layer from damage. For this purpose suitable overlay papers preferably have a paper web as the core layer, which is impregnated by means of a resin, provided with hard particles of different sizes and then dried. The overlay paper thus forms a compact, resistant layer which is to be applied to a decorative layer by means of a press plate, for example, the resulting surface of the resulting laminate resulting from the impression of the surface of the press plate.

It is already known to apply fine and coarse hard particles to the paper web to achieve the desired mechanical properties of the laminate such as abrasion resistance, rub resistance and press plate protection for the laminate production process, the fine hard particles preferably being attached to the surface, i. H. the final usable area of the finished laminate should be directed. The hard particles may consist of alumina (corundum), silica, titania, tin oxide, zirconia or other mineral or ceramic materials.

The application of two hard particle layers on an overlay paper in the prior art requires the impregnation of a paper web, so that a saturation of the paper is achieved, which allows the subsequent application of different particle layers. Methods are known in which an intermediate drying is carried out after application of a particle layer having a first size to the impregnated paper web so that a particle layer applied thereto with particles of a second size does not lead to a mixing with the particles of the first size.

The publication EP 2 090 695 B1 also shows a method for producing an overlay, in particular for laminates, in which a paper web moistened on one side is impregnated in the core, then in a so-called wet-on-wet application a coarse corundum resin dispersion is applied on one side, after which a coating mass in a mutual wet film is applied. In wet process is applied.

SUMMARY OF THE INVENTION

The above-mentioned methods, in which an additional layer is applied to an inter-dried overlay paper, require the interruption of a drying channel or the integration of a pre-drying channel in an installation for the production of overlays, resulting in additional costs in the production of overlay papers as well a longer processing time and a higher power consumption results.

Such methods are still difficult to retrofit, because the integration of a pre-drying channel or the integration of an additional processing station requires a sufficient amount of space, which will be available only in the rarest of cases unused.

The object of the invention is therefore to propose an overlay, in particular for laminates, and a method for producing abrasion-resistant overlays, in particular for laminates, which reduces or completely eliminates the disadvantages mentioned above. In particular, the manufacturing process should be carried out economically and at the highest possible speed on conventional equipment for producing overlay papers, without requiring major modifications to particle size processing steps.

The object is achieved by a method having the features of independent claim 1. Advantageous further developments and embodiments can be found in the subclaims.

In an advantageous embodiment of the method according to the invention, the steps of unrolling an overlay base paper from a roll to form a recoverable paper web, two-sided wet-on-wet application (dipping) of a dispersion of resin and fine hard particles onto the paper web and metering are successively performed the job, the one-sided wet-on-wet application of a dispersion of resin and coarse hard particles on the paper web and metering of the job and then carried out uninterrupted, single-stage drying of the paper web in a drying channel.

This process differs significantly from already known manufacturing processes. The two-sided wet-on-wet application of a dispersion of resin and fine hard particles leads to the fact that both layers (top and bottom) of the impregnated overlay base paper have fine hard particles, which facilitates the production and impregnation by the passage of the paper web through a dip tank. Consequently, the side of the overlay base paper, on which coarse hard particles are subsequently applied, also has fine hard particles as well as the other and later outer surface of the overlay. Thus, the fine hard particles are located both on the top and on the bottom of the overlay according to the invention.

The subsequent dosing allows the removal of excess resin material so that the paper web coated on both sides has a predetermined thickness. This dosage can be done for example by means of a metering roller pair whose distance from one another determines the resulting thickness of the paper coated on both sides.

By the subsequent unilateral exposure to coarse hard particles, present in a resin dispersion, the second particle layer is produced. Applying the dispersion of resin and fine hard particles beforehand on both sides results in dip impregnation, so that the dispersion with coarse hard particles can not penetrate through the base paper to the other side. The subsequent dosing finally allows the adjustment of the overall thickness of the overlay, so that subsequently only a continuous, uninterrupted and desired final drying must be carried out.

The particular advantages of this method are that a complete wet-on-wet application can be carried out without having to perform a costly intermediate drying. At the same time can be dispensed with an additional processing station, which would make an isolated one-sided coating with fine hard particles, after already coarse hard particles were applied on one side.

In an advantageous embodiment, before applying the dispersion of resin and fine hard particles on both sides, a resin material is applied to the paper web (rinsed) on one side. This initial scouring of the resin material causes the paper to impregnate, causing diffusion of the resin material into the pulp tissue of the paper to completely displace air from the interstices of the pulp fibers. A penetration of a subsequently applied on one side of the paper material through the paper on the other side of the paper is no longer possible. Furthermore, a particularly good connectivity with a further resin layer is caused.

In an advantageous embodiment, the unilaterally applied resin material is a dispersion of resin and fine hard particles. This has the effect that when diffusing the resin into the pulp fiber interstices in addition to the resin itself already fine hard particles are carried into the fibers and thus adhere very close to the surface of the paper, while displacing the air located between the pulp fibers. The overlay would not only contain fine particles on both sides of the paper, but also in its core.

In an advantageous embodiment, following the one-sided application of the resin material, the paper web is conveyed through a conveying path without further processing steps to obtain a contact time for the resin material. This allows the overlay base paper to pick up resin material and achieve saturation by displacing the air from the interstices between pulp fibers.

In an advantageous embodiment, one side of the paper web is provided with a dispersion of resin and coarse hard particles which is opposite to the side of the paper web on which the one-sided application of the resin material has been carried out. This could allow a more homogeneous overlay design with a center base paper layer and about the same resin layer thicknesses on both sides of the paper.

In an equally advantageous embodiment, however, the side of the paper web can be provided with a dispersion of resin and coarse hard particles, which is also provided with the one-sided application of the resin material. As a result, loops of the paper web can be drawn without major deflection and without application processes from different directions through two equally aligned dip tanks, whereby the manufacturing process is simplified.

In an advantageous embodiment, the fine hard particles have a size of 0.5 .mu.m to 50 .mu.m. This is particularly advantageous in order to achieve a press plate protection and at the same time to ensure an optically clear and yet scratch-resistant surface. Particularly advantageously, the size of the fine hard particles is in a range of 1 .mu.m to 30 .mu.m.

In an advantageous embodiment, the coarse hard particles have a size of 30 to 120 μm. This causes a particularly high abrasion resistance, since the coarse hard particles high surface loads can be very well absorbed.

In an advantageous embodiment, the dispersion with coarse hard particles also contains fine hard particles. The coarse and fine hard particles are present simultaneously in mutually selectable, percentages by weight. Thus, the described fine hard particles with a size of 1 .mu.m to 30 .mu.m are respectively present on the top and bottom of the overlay impregnate prepared and dried according to the invention. This allows a free choice of positioning of the overlay impregnate with respect to the top and bottom in the subsequent processing in the pressing process. Nevertheless, if coarse hard particles are not too large, adequate pressure plate protection can be achieved, but at the same time the abrasion resistance can be increased.

The base paper to be coated, having cellulosic fibers, preferably has a basis weight of 18-45 g / m ² . The mass fraction of the fine and coarse hard particles in the respective dispersion can be adjusted depending on the required mechanical properties. For example, for the fine and coarse hard particles, a mass fraction of 0.5% -50% of the total mass of the respective dispersion is selected, wherein mass fractions of 3-30% have been found to be particularly suitable. The mass fractions are based on dry resin.

Depending on the desired thickness, the individual coating layers can have a weight per unit area of between 1 g / m ² and 80 g / m ² (based on the weight of dry resin), basis weights of between 5 g / m ² and 50 g / m ² being particularly suitable ,

An overlay made by the method described above can also achieve the object of the invention. In one advantageous embodiment, the overlay has a respective layer of a resin with dispersed fine hard particles on each side and an outwardly adjoining layer of a resin with dispersed coarse hard particles on one of the two sides of the base paper. Preferably, the base paper is impregnated by means of a resin material, which is applied on one side of the base paper.

The use of such an overlay for the manufacture of a floor element is particularly advantageous because the scratch and abrasion resistant coating can be made cheaper and easier to give the floor element the desired mechanical properties.

Finally, a laminate floorboard comprising a substrate and an overlay thereon according to the invention also solves the invention. The carrier material may be a material in the form of a chipboard or fiberboard, wherein the base material may be a wood or cellulose material.

BRIEF DESCRIPTION OF THE FIGURES

Other features, advantages and applications of the present invention will become apparent from the following description of the embodiments and the figures. All described and / or illustrated features alone and in any combination, the subject matter of the invention, regardless of their composition in the individual claims or their relationships. In the figures, the same reference numerals for identical or similar objects.

1 shows a simplified sectional view of the required for carrying out the method according to the invention aggregates or stations a plant for producing overlays, in particular for laminates.

2 shows a schematic, block-based representation of a method according to the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

1 shows the essential, necessary for carrying out the method according to the invention aggregates or processing stations a plant for the production of overlays, especially for laminates. The processing station I is a so-called "unrolling station", in which rolls of an overlay base paper are stored and can be unrolled for further processing. In the illustration shown, the unwinding station merely has a first paper roll by way of example 2 and a second paper roll 4 on, being from the first paper roll 2 a paper web 6 unrolled and conveyed to the next processing station and automatically upon complete removal of the paper of the first paper roll 2 the paper web of the second paper roll 4 with the paper of the first paper roll 2 is glued.

Usually, the unwind station I includes a paper tension regulator for adjusting the paper tension, or such a paper tension regulator is arranged downstream of the unwinding station I. The leadership of the paper web 6 for subsequent processing is thereby improved and there are damage due to vibration effects or hitting the paper web 6 prevented.

In the following processing station II is on one side of the unrolled paper web 6 applied a dispersion of resin and fine hard particles ("rinsing") by the paper web 6 through a tub 8th with a dispersion therein is guided so that only a single side of the paper web 6 is charged with this material.

Subordinated is an optional processing station III, which is also called "breathing route". Here is the one-side rinsed, coated paper web 6 moved over a sufficiently long and adjustable in length conveyor line to the paper web 6 to allow sufficient time to infiltrate or diffuse fine dispersion particles. In this workstation 3 becomes the paper web 6 so saturated that there is no longer any air in the spaces between the pulp fibers of the paper.

In a downstream her processing station IV, the entire paper web 6 through a dip tank 10 passed, which contains a dispersion of resin and fine hard particles. After that is about a pair of metering rollers 12 whose distance from one another can be set exactly to one thousandth of a millimeter, the amount of dispersion absorbed by the paper is set exactly by specifying a material thickness.

In a further downstream station V, the paper web 6 under an applicator 14 guided along, which gives a dispersion of resin and coarse hard particles and optionally also contains fine hard particles. Subsequently, over another pair of metering rollers 16 adjusted the recorded amount of the coarse hard particles containing dispersion.

Finally, the entire paper web 6 continuously into a drying channel VI, in which it is dried in an uninterrupted operation promoted.

According to the invention, no interim drying steps are necessary by the wet-on-wet coating method of coarse hard particle-containing dispersion on fine hard particle-containing layer. Furthermore, according to the invention, the steps of impregnating and applying fine hard particles can be combined in an advantageous manner, so that the in 1 shown plant with significantly fewer components and cheaper to operate than in the prior art. At the same time, the processing speed is increased and the energy consumption is lowered.

2 Finally, a block-based representation of the method according to the invention, which shows the steps of unwinding 20 an overlay base paper from a paper roll 2 . 4 for forming a recoverable paper web 6 , of one-sided application 22 a dispersion of resin and fine hard particles on the paper web 6 , two-sided wet-on-wet coating 24 a dispersion of resin and fine hard particles on the paper web 6 , dosing 26 order, one-sided wet-on-wet application 28 a dispersion of resin and coarse hard particles on the paper web 6 and dosing 30 the job and the subsequent drying 32 the paper web 6 in a drying channel 18 includes. The dispersion with coarse hard particles may also have fine hard particles, so that the resulting overlay can also be used on both sides.

In addition, it should be noted that "having" does not exclude other elements or steps, and "a" or "an" does not exclude a plurality. It should also be appreciated that features described with reference to any of the above embodiments may also be used in combination with other features of other embodiments described above. Reference signs in the claims are not to be considered as limiting.

LIST OF REFERENCE NUMBERS

2

paper roll

4

paper roll

6

paper web

8th

order station

10

order station

12

metering

14

applicator

16

metering

18

drying channel

20

Unrolling the paper

22

One-sided application

24

Two-sided wet-on-wet application

26

Dosing the job

28

One-sided wet-on-wet application

30

Dosing the job

32

dry

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2090695 B1 [0005]

Claims (17)

Method for producing an overlay, in particular for laminates, comprising the following steps: 20 ) of an overlay base paper ( 2 . 4 ) from a roll for forming a recoverable paper web ( 6 ); - Two-sided wet-on-wet application ( 24 ) of a dispersion of resin and fine hard particles on the paper web ( 6 ) and dosage ( 26 ) of the order; - One-sided wet-on-wet application ( 28 ) of a dispersion of resin and coarse hard particles on the paper web ( 6 ) and dosage ( 30 ) of the order; and - then an uninterrupted one-stage drying ( 32 ) of the paper web ( 6 ) in a drying channel ( 18 ). Method according to claim 1, wherein prior to application on both sides ( 24 ) a dispersion of resin and fine hard particles, a resin material on one side of the paper web ( 6 ) ( 22 ) becomes. A method according to claim 2, wherein the unilaterally applied resin material is made of a dispersion of resin and fine hard particles. Method according to Claim 2 or 3, in which, following the one-sided application of the resin material, the paper web ( 6 ) is conveyed through a conveying path without further processing steps to obtain an exposure time for the resin material. Method according to one of Claims 2 to 4, in which one side of the paper web ( 6 ) is provided with the dispersion of resin and coarse hard particles, the side of the paper web ( 6 ), on which the one-sided mission ( 22 ) of the resin material. Method according to one of claims 2 to 4, wherein the side of the paper web ( 6 ) is provided with the dispersion of resin and coarse hard particles, which also with the one-sided order ( 22 ) of the resin material. Method according to one of the preceding claims, in which the dispersion with coarse hard particles also has fine hard particles. Method according to one of the preceding claims, wherein the fine hard particles have a size of 0.5 microns to 50 microns. Method according to one of the preceding claims, wherein the fine hard particles have a size of 1 micron-30 microns. Method according to one of the preceding claims, wherein the coarse hard particles have a size of 30 microns-120 microns. A method according to any one of the preceding claims, wherein intermediate drying is not performed between the step of applying a dispersion of resin and fine hard particles and the dispersion of resin and coarse hard particles. Method according to one of the preceding claims, wherein the individual coating layers have a basis weight based on dry resin between 1 g / m ² and 80 g / m ² . Method according to one of the preceding claims, wherein the hard particles are made of at least one material of a material group having the material group: - alumina (corundum), Silica, - titanium oxide, Tin oxide, Zirconium oxide, - mineral materials, and - ceramic materials. An overlay comprising a base paper and a respective layer of a dispersed fine hard particle resin on each side of the base paper and an outermost layer of a dispersed coarse hard particle dispersed resin on either side of the base paper. An overlay according to claim 14, wherein the base paper is impregnated on one side with a resin material. Use of an overlay according to claim 14 for the production of a floor element. Laminate floorboard, comprising a carrier material of a fiber or wood-based material and an overlay according to claim 14.

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