CN113165203A

CN113165203A - Method for increasing rolling wear resistance of transportation floor panel, transportation floor panel and floor structure

Info

Publication number: CN113165203A
Application number: CN201980078207.1A
Authority: CN
Inventors: 卡斯佩里·索卡; 尤西·埃克曼; 米拉·辛迪卡
Original assignee: METSAELIITTO OSUUSKUNTA
Current assignee: METSAELIITTO OSUUSKUNTA
Priority date: 2018-11-30
Filing date: 2019-11-29
Publication date: 2021-07-23
Also published as: FI20186031A1; FI128959B; WO2020109669A3; EP3887108A2; WO2020109669A2

Abstract

A transport floor, a method for the production thereof and the use thereof. The present invention provides a method of increasing the rolling wear resistance of a transportation floor panel. Thus, in a panel comprising a multilayer panel formed from a plurality of wood veneers and a cover layer bonded to the top veneer of the panel and forming a surface of the panel, the top veneer of the multilayer panel is saturated with a hydrophobic agent prior to attaching the cover layer to the top veneer. The veneer layer containing the wood fibers filled with the water repellent agent will act as a damping layer which reduces the pressure caused by the rollers and thereby improves the resistance of the panel to the shear strain applied to the surface of the panel by the high pressure caused by the rollers.

Description

Method for increasing rolling wear resistance of transportation floor panel, transportation floor panel and floor structure

Technical Field

The present invention relates to a transportation floor panel. In particular, the present invention relates to a method of increasing the shear strain resistance of a transportation floor panel, in particular shear strain caused by rolling wear. The invention also relates to a transport floor panel comprising a multi-layer panel with a covering layer, and to a floor structure for a freight vehicle.

Background

Plywood panels are commonly used as flooring in freight vehicles and trailers. To this end, they are typically provided with a wire mesh patterned surface to increase friction between the floor and any loaded or stored goods, and between the floor and any wheels or rollers that move over the floor.

Floor panels are expected to have good mechanical properties, in particular the panels should be able to withstand shear strains applied to the surface of the panel. The shear strain is caused, for example, by rolling wear. Small, hard wheels of, for example, manual pallets, which are commonly used for loading, unloading and handling goods, cause very high surface pressures and, therefore, very high strains on the flooring. Despite low wheel loads, i.e. about 3-4 kN/wheel, the surface pressure exerted by a 1.5 ton hand-operated trailer can be as high as 2-5N/mm². The hard and small nylon wheels of the retail dispensing cart may cause even greater surface pressure as the retail dispensing cart moves along the vehicle floor made of plywood. In thatIn these cases, the surface load may rise to 5-15N/mm, although the wheel load may only be about 1-2 kN/wheel²。

The greatest surface pressure is directed to the panel cover layer and the surface veneer immediately below. When the strain due to the roll becomes too high, the surface veneer may crack, splitting in the middle of the veneer in the direction of the glue joint.

Birch plywood has significantly better rolling wear resistance than combination plywood. This is because the rolling shear strength of birch veneers is higher than that of spruce veneers.

However, even if made of birch plywood, the rolling wear resistance of conventional flat floor panels is still unsatisfactory.

In the art, various solutions have been proposed to enhance the mechanical properties of floor panels by using a mechanically strong covering, for example consisting of a material comprising an epoxy resin material or reinforced by such a material. However, such materials are often expensive and even if the mechanical strength is increased, the total cost of the floor panel becomes unacceptably high. Epoxy materials are also difficult to apply to panel surfaces by conventional plywood processes.

There is a need for a new type of transportation floor panel with enhanced mechanical strength, in particular against shear strains caused by rolling wear and similar surface pressures, which can be manufactured substantially by conventional plywood manufacturing processes.

Disclosure of Invention

It is an object of the present invention to provide a method for increasing the rolling wear resistance of a transportation floor panel.

It is another object of the present invention to provide a transportation floor panel comprising a multi-layer panel.

A third object of the invention is to provide a floor structure of a freight vehicle.

The present invention is based on the discovery that for transportation floor panels, which typically have a friction-enhancing covering, the strength of the panel against shear strains can be enhanced by impregnating, preferably saturating, the top veneer beneath the covering with a hydrophobic agent. Surprisingly, it has been found that the top veneer after such treatment will effectively reduce the pressure caused by the rollers and improve the rolling wear resistance of the floor panel.

Accordingly, the present invention provides a method of increasing the resistance of a transportation floor panel, the panel comprising a multi-layer panel formed from a plurality of wood veneers and a cover layer bonded to a top veneer of the panel and forming a surface of the panel by saturating the top veneer with a water repellant prior to attachment of the cover layer to the top veneer.

More specifically, the invention is characterized by what is stated in the characterizing part of the independent claims.

According to a first aspect of the present invention, there is provided a method of increasing the rolling wear resistance of a transportation floor panel, the panel comprising:

-a multi-layer panel formed of a plurality of wood veneers, and

-a cover layer bonded to the top veneer of the panel and forming a surface of the panel,

wherein the top veneer of the multi-layer panel is impregnated with a hydrophobic agent prior to attaching the cover layer to the top veneer. Various embodiments of the first aspect may include at least one feature from the following bulleted list:

applying the hydrophobic agent to the top veneer from a composition comprising the hydrophobic agent in an amount of 10 to 100 wt%, such as 60 to 100 wt%.

The hydrophobic agent is selected from the group of waxes, oils, fats, fatty acids, alkanes, alkenes, their derivatives and mixtures thereof.

Paraffin, silicone oil or olefin ketene dimer is used as hydrophobing agent.

Paraffin or olefin ketene dimer, which is used in solid form and is melted before or during application onto the top veneer, is used as hydrophobing agent.

The amount of water repellent applied to the surface of the wood panel is from 20 to 100g/m²。

Applying a hydrophobic agent on the top veneer such that the wood fiber cavities are filled with the hydrophobic agent.

Applying the hydrophobizing agent to the top veneer such that at least a portion of the hydrophobizing agent will migrate from the top veneer to the next veneer below it.

Applying a hydrophobic agent to the top veneer such that at least the top veneer and the veneer below it will be saturated with the hydrophobic agent.

The cover layer comprises a layer having a rough surface, in particular a cover layer having a wire mesh patterned surface.

The overlay layer comprises a phenolic coating layer having a surface weight of about 100-300g/m²E.g. 120-220g/m²。

The phenolic coating layer comprises a paper substrate impregnated with a phenolic resin, the grammage of the paper substrate being from 40 to 80g/m²And contains 80 to 140g/m²A phenolic resin.

The cover layer comprises a paper substrate impregnated with phenolic resin, which is applied by pressing, in particular by hot pressing, on the surface of the top single sheet of the multilayer panel.

Attaching the cover layer to the top veneer using a hot press with a platen having a wire mesh patterned surface.

Attaching the overlay to the top veneer using a phenolic resin, in particular a thermally activated phenolic resin, impregnated in a substrate such as a non-woven substrate.

The panel can resist up to 15kN/mm²Without the top veneer cracking, particularly any of the three top veneers.

According to a second aspect of the invention, a transport floor panel is provided, obtained by the method according to the first aspect.

According to a third aspect of the present invention, there is provided a transport floor panel comprising a multilayer panel formed from a plurality of wood veneers and a coating layer bonded to a top veneer of the panel and forming a surface of the panel, wherein the top veneer of the multilayer panel is impregnated with a water repellant; and the cover layer has a rough surface for enhancing friction between the surface of the cover layer and the roller.

Various embodiments of the third aspect may include at least one feature from the following bulleted list:

the cover layer is formed by a phenolic coating layer having a first rough surface able to face the roll and an opposite second smooth surface.

The cover layer has a wire mesh patterned surface that can face the roller.

The cover layer comprises a paper substrate impregnated with phenolic resin, which cover layer has been applied by pressing, in particular by hot pressing, on the surface of the top single sheet of the multilayer panel.

The cover layer has been attached to the top veneer using hot pressing with a platen having a wire mesh patterned surface.

The hydrophobing agent is selected from the group of waxes, oils, fats, fatty acids, alkanes, alkenes, their derivatives and mixtures thereof, in particular paraffins, silicone oils and alkene ketene dimers.

-at least the wood fibre cavities of the top veneer are filled with a hydrophobic agent.

According to a fourth aspect of the invention there is provided a floor structure for a freight vehicle comprising a frame and a floor formed from one or more transport floor panels attached to the frame, the panels comprising one or more panels according to the third aspect.

Various embodiments of the fourth aspect may include at least one feature from the following bulleted lists:

the floor structure comprises the frame of a train wagon, a ship such as a ro-ro ship, a trailer, a cart or a truck.

Considerable advantages are obtained by the invention. The present invention thus provides an effective means for improving the resistance of a panel to shear strain applied to the surface of the panel by high surface pressure caused by, for example, rollers, without the need for expensive epoxy-type polymer reinforcements.

This improvement can be achieved when the hydrophobic agent is caused to penetrate into the grain of the wood layer so that it displaces the water within the wood fibers. The veneer layer containing the hydrophobic agent-filled wood fibers will then act as a hydro-elastic layer, which reduces the pressure caused by the rollers. Of course, this is only one possible explanation and the scope of the invention should not be construed as being limited to the proposed explanation.

The hydrophobic agent may be applied on the top veneer by conventional application methods and after application of the hydrophobic agent, the overlay may be attached to the top veneer layer so treated by using a separate glue layer or by resin that migrates from the overlay into the top veneer during hot pressing of a conventional plywood overlay.

It has been found that the bond between the cover layer and the top veneer is not weakened by the hydrophobizing agent if the hydrophobizing agent penetrates the wood grain.

Further features and advantages of various embodiments of the present invention will appear from the following detailed description.

Drawings

The figure shows a cross-section of a panel according to an embodiment of the invention in a side view.

Detailed description of the preferred embodiments

By the present technique, a method for increasing the rolling wear resistance of a transportation floor panel is provided, which method comprises impregnating at least the top veneer of a multilayer panel with a hydrophobizing agent before applying and in particular hot pressing a cover layer to the top veneer.

In one embodiment, the present type of transportation floor panel comprises a wood panel with a covering having a rough surface for enhancing surface friction.

In the drawings, the main components of the panels of embodiments of the present technology are disclosed.

Reference numeral 4 therefore denotes a multi-layer panel comprising a plurality of superimposed layers of wood, for example of wood veneer. Reference numeral 3 designates the top layer of the multilayer panel, which has been impregnated with a hydrophobic agent, which will be discussed in more detail. Reference numeral 1 relates to a covering layer forming the upper surface of the floor panel, and reference numeral 2 denotes a glue layer for gluing the covering layer 1 to the top layer 3.

"floor panel" means a wood panel used for or as a floor, either alone or preferably in combination with a support structure such as a frame. Generally, the floor panel of the present invention is used in a transport vehicle, wherein the floor consists of a plurality of floor panels placed in a transverse and longitudinal configuration (i.e., side by side, and one after the other) to form the floor of the vehicle.

"impregnation" refers to the act of infiltrating a material (e.g., a veneer, at least the top veneer of a panel) with a hydrophobic agent. "soak" is used to indicate that the impregnation has proceeded to the point where the veneer is unable to take up (absorb) more of the hydrophobic agent under the prevailing conditions.

In the context of the present invention, the term "wood panel" refers to a board comprising a plurality of overlapping and/or superimposed wood layers (hereinafter also referred to as "multi-layer panel" or "multi-layer structure").

"Multi-layer panel", such as that shown in the drawings and designated by the numeral 4, represents a panel comprising a plurality of overlapping and/or superimposed layers of sheet material. There are at least 2 layers, preferably at least 3 layers of such materials. There may be up to about 250 overlapping and/or superimposed layers, although in practice the maximum number is typically less than 100. The sheet material may be continuous, or it may consist of several sheets oriented in the same plane; typically, at least a substantial portion of the layer of sheet material is formed from wood veneers or strands.

The term "wood-based layer" includes, for example, wood veneers and wood strands.

In one embodiment, the multi-ply panel comprises or consists essentially of a plurality of wood veneer layers.

However, there may also be multiple layers of materials that can impart preselected mechanical or chemical properties. Examples of such materials are metal foils, such as aluminum foils and films, textile layers, for example nonwoven sheets, polymeric films and sheets, such as polyolefin, polyamide and EVOH films for barrier purposes and polyamide and polyaramide films and fabrics for structural purposes.

Generally, in the multi-layer panel of the present invention, most of the layers are or include a wood material.

Sheet materials are typically bonded together using intermittent and/or intralayer adhesive layers.

The terms "sheet" and "panel" are used interchangeably and refer to a piece of material having at least one flat surface. Preferably, the "sheet" (or "panel") has two opposing flat surfaces that are oriented substantially parallel.

Typically, in this context, the core sheet material is an elongated flat structure. The dimensions are in the range of 10-15,000mm by 10-20,000 mm. In particular, the sheet of the present invention has a width of 50-2,500mm and a length of 300-13,500 mm. The thickness of the "core sheet" is typically between 3 and 250mm, in particular between 4 and 120 mm.

In the context of the present invention, "one-step pressing" means a pressing process in which a stack formed by overlapping and/or superposed layers of structural material and binder is pressed by a pressing operation, usually in one pressing station, until a predetermined compressive strength of the board is obtained. The pressing may be performed by applying a continuously increasing compression or by applying the compression in successive stages of different pressures.

"stacked" means an organized stack of overlapping and/or superimposed layers.

"hot pressing" means pressing at an increased temperature and surface pressure (compared to ambient conditions) over a period of time.

In accordance with embodiments of the present technique, a method for producing a panel suitable for flooring purposes is provided.

One embodiment comprises a combination of the following steps:

-providing a wood based material in the form of a plurality of layers of such material and an adhesive suitable for bonding said layers to each other; and

-arranging layers of wood based material in a stack with adhesive between the layers of wood based material.

Any functional layers (see below) are preferably added to the stack.

This method is often referred to as a "one-step method" because all layers are first stacked and then the entire stack is pressed in one step.

The pressing is typically carried out at a temperature of 120-225 deg.C, such as 120-160 deg.C, for a time period of about 4-90 minutes, and at a pressure of 1-2.5MPa, such as 1.1-1.7 MPa.

The wood-based material used to form the core board material is obtained by stripping or cutting a suitable wood raw material.

Typically, the wood layer or strip is made of softwood or hardwood, such as spruce, pine, larch, birch, poplar, aspen, alder, eucalyptus, or mixed tropical hardwood, or combinations thereof.

A particularly preferred embodiment comprises the use of a hardwood, such as birch, at least as the top veneer, in particular the panel comprises only a hardwood, such as birch, as the wood veneer layer.

The thickness of the wood-based layer is generally about 0.5 to 5mm, in particular about 0.9 to 3.5 mm.

In one embodiment, the wood based layer is comprised of wood veneer. The core sheet is typically a multi-layer veneer panel or a veneer laminate.

In another embodiment, there are one or more layers of non-wood material in the stack. These layers, also referred to as "functional layers", will provide improved mechanical, chemical, biological and acoustic properties to the final product. The thickness of such non-wood layers is about 0.01-5 mm. The thickness is typically 0.01-0.5mm for metal foils, 0.1-3mm for polymer layers and about 0.5-5mm for cork layers.

The wood-based layer and the optional non-wood layer are bonded together with an adhesive (not shown in the figures). The binder may be a binder resin. The binder resin may be provided in dry powder form, for example as a hot melt adhesive, or as a liquid or as a combination thereof. The adhesive may be applied to form an adhesive layer that uniformly covers at least a portion, in particular all or substantially all, of the adjacent surface. The adhesive may also or alternatively be applied in discrete dots or stripes.

The binder is in particular a thermosetting polymer. Such polymers may be selected from the group of phenol-formaldehyde binders, melamine-formaldehyde binders, urea-formaldehyde binders, polyurethane binders and lignin-based resins and combinations thereof. The adhesive may be applied on the wood-based material layer and the non-wood material layer in a manner known per se, for example by coating or spraying. In one embodiment, the binder is applied in the form of a fibrous sheet impregnated with the binder.

In order to meet the requirements of the floor panels, the wood panels of the invention are provided with a friction-enhancing covering (reference numeral 1 in the drawings). While the present technique will also improve the shear strain resistance of panels having smooth surfaces that provide low friction between the surface of the panel and any cargo placed thereon, the present technique is particularly advantageous for floor panels having a friction enhanced surface. Such a surface is often rough or uneven and will reduce or prevent the risk of slipping of goods placed on the floor panel.

In one embodiment, the surface of the panel is granular. Such surfaces may have a plurality of protruding points to enhance friction.

In one embodiment, the surface has a regular pattern with linear depressions separated by ridges, thereby defining a grid on the surface.

During processing, the surface of the panel may be provided with a friction enhancing pattern. In such an embodiment, the cover layer is then simply hot pressed onto the wood panel. In one embodiment, the surface is wire mesh patterned, which can be achieved by using a platen with a corresponding pattern. In another embodiment, an engraved template or master with a suitable pattern is used during pressing in order to impart a friction enhancing surface pattern on the surface of the panel.

After hot pressing the coating, the friction enhancing web may also be bonded to the surface in a separate stage.

To improve the shear strain of the floor panel, a hydrophobic agent is applied on the top veneer (reference numeral 3 of the drawing).

In one embodiment, the hydrophobic agent is selected from the group of waxes, oils, fats, fatty acids, alkanes, alkenes, derivatives thereof and mixtures thereof.

In particular, the hydrophobing agent is selected from paraffin, silicone oil or olefin ketene dimer. Olefin ketene dimer (abbreviated AKD) is particularly preferred because it has an affinity for the hydroxyl groups present in wood.

In one embodiment, the hydrophobizing agent is applied from a composition comprising the hydrophobizing agent in an amount of from 10 to 100 wt%, such as from 60 to 100 wt%. The hydrophobicizing agents can therefore be used in the form of dispersions, in particular aqueous dispersions, or as solid materials.

Preferably, a paraffin or olefin ketene dimer is used as the hydrophobizing agent, and the paraffin or olefin ketene dimer is used in solid form. The solid material is then melted before or during application to the top veneer.

To achieve saturation, a hydrophobic agent is preferably applied on the top veneer such that at least the wood fiber cavities of the top veneer are filled with the hydrophobic agent. Furthermore, in a particularly preferred embodiment, the hydrophobizing agent is applied to the top veneer such that at least a portion of the hydrophobizing agent will migrate from the top veneer to the next veneer below it.

In one embodiment, the hydrophobic agent will penetrate to a depth of at least 50%, particularly at least 75%, particularly at least 90% of the total thickness of the top veneer.

In one embodiment, the hydrophobic agent is applied on the top veneer such that at least the top veneer and the veneer below it will be impregnated or even saturated with the hydrophobic agent.

Typically, in order to achieve a thorough treatment of the top veneer, the amount of hydrophobizing agent, such as AKD, applied on the surface of the wood board is at least 5g/m²In particular at least 10g/m²Preferably 15 to 300g/m²E.g. 17-100g/m²Or 20-100g/m²、20-75g/m². In one embodiment, the amount of hydrophobic agent is about20-55g/m²。

The hydrophobizing agent can be applied by spraying or coating, in particular by roll coating. The hydrophobic agent may be applied to the veneer in 1-5 parts. Thus, in one embodiment, about 15-25g of hydrophobic agent is applied 1 to 3 times. The spacing between applications will be sufficient to allow the hydrophobizing agent to at least partially migrate into the wood before the next portion of hydrophobizing agent is applied. The overlay covering the top veneer typically comprises at least one polymer resin coating layer having about 100-300g/m²Surface weight of, for example, 120-220g/m². The "polymer coating layer" is preferably a layer formed of a resin selected from the group consisting of a phenol-formaldehyde binder, a melamine-formaldehyde binder, a urea-formaldehyde binder, a polyurethane binder, and a lignin-based resin, and combinations thereof. In particular, the cover layer comprises a phenol-formaldehyde resin.

In one embodiment, the phenolic coating layer comprises a paper carrier substrate impregnated with a polymer resin, the paper substrate having 40-80g/m²And comprises 80-140g/m²Such as a phenolic resin.

Thus, in one embodiment, the cover layer comprises a paper substrate impregnated with resin, which cover layer has been applied by pressing, in particular by hot pressing, on the surface of the top veneer of the multilayer panel. Generally, in pressing a wood panel by using a press plate having a wire mesh pattern, a surface is given the structure.

The hot pressing of the coated panel is typically performed at a temperature of 120-225 deg.C, such as 120-200 deg.C, for a time period of about 30-900 seconds, and at a pressure of 1.1-3MPa, such as 1.5-2.4 MPa.

To attach the cover layer to the top veneer, resin is used. The adhesive resin layer is depicted at reference numeral 2 of the drawing. The resin may be selected from the group consisting of phenol-formaldehyde binders, melamine-formaldehyde binders, urea-formaldehyde binders, polyurethane binders, and lignin-based resins, and combinations thereof. Preferably, a phenolic resin or a polyurethane resin is used, in particular a heat activated resin, such as a heat activated phenolic resin.

Such a glue layer (or adhesive layer) 2 firmly bonds the coating layer to the surface of the top wood veneer layer even when the wood veneer layer has been saturated and at least partially saturated with a water repellent agent.

The resin may be applied by coating, brushing, rolling or spraying. In a preferred embodiment, the resin application is impregnated in a carrier substrate, such as a nonwoven substrate, which is placed as a material sheet between the top layer and the cover layer and then bonded to the cover layer and the top layer during hot pressing.

Thus, in one embodiment of the present invention, a composite laminate is formed that is securely bonded to the top veneer, the composite laminate comprising two overlapping and/or overlying carrier substrates, both of which are impregnated with resin and wax after pressing, and which cannot be separated without rupturing the composite laminate. Typically, the composite laminate is so strongly bonded to the top veneer that the composite laminate cannot be separated from the top veneer without cracking the veneer.

Based on the foregoing, the present technology provides a transportation floor panel comprising a multi-layer panel formed of a plurality of wood veneers and a cover layer forming a surface of the panel, the transportation floor panel having enhanced resistance to shear strain caused by rolling wear.

As described above, floor panels according to the present techniques and various embodiments discussed may be used to provide a floor structure, for example, a floor structure suitable for a cargo vehicle or trailer. The floor structure typically comprises a frame and a floor formed by one or more transport floor panels of the present type attached to the frame. The panels may be mechanically bonded to the frame, or they may be glued to the frame, or they may be bonded by a combination of these steps.

Examples of uses for the floor panel of the present invention include as a floor for train wagons, boats such as ro-ro ships or trucks. It has been found that with embodiments of the present technology, rolling resistance of the same order of magnitude as that obtained with thicker and more expensive cover layers used, for example, in commercial products, can be achieved.

Examples

A 30mm birch laminate was made in a conventional manner and hot pressed into a multi-layer panel.

The top wood veneer of the multi-layer panel is sanded after pressing to smooth the surface. The solid AKD wax was then melted and applied at about 50g/m²Spread over the surface.

An impregnated nonwoven adhesive film comprising a low molecular PF resin was applied to the surface treated with AKD wax applied by a coating roll. On the uncured adhesive film, at 80g/m²Placing on kraft paper with a weight of 220g/m²A second film (coating film) of Phenol Formaldehyde (PF). The stack and coating film formed by the multilayer panel with PF resin film was then covered by hot pressing at 138 ℃ at 2.2MPa for 12 minutes during the high pressure section of the hot pressing schedule.

The rolling wear resistance was tested by means of a roller tester. In the tester, a steel wheel of 125mm diameter and 50mm width is used, which is capable of exerting a pressure of 2kN on the plywood surface, by moving the tester in a pattern over the panel surface. The surface pressure exerted by the wheel is about 2-4N/mm²Depending on the embossing of the wheel in the panel surface. Rolling wear resistance is expressed in terms of the number of revolutions the wheel of the tester makes at the wear point. This test method corresponds quite closely to the swedish standard SS 923508.

Table 1 gives the results of the tests carried out as described above.

TABLE 1

In the table, the following abbreviations are used:

"W" means wax (AKD), "1 xW" means wax applied once with a coating roll, and "2 xW" means wax applied once with a coating rollWax was applied twice with the applicator roll, "3 xW" means wax was applied three times with the applicator roll; "adhesive film" means PF resin film, and "220" means 220g/m²A phenol formaldehyde resin coating film of (2).

For one application with a coating roll, the amount of wax applied is about 20-25g/m²。

As can be seen from the test results, the application of the combination of wax, resin film and coating film will provide a significant improvement in the rolling wear resistance of the multilayer panel. About 20 to 25g/m as compared with the case where the coating film is bonded to the surface of the multi-layer panel with the resin film²Adding wax (e.g., AKD) to the top veneer will already produce a rolling resistance 1.75 times greater than the corresponding panel without wax. For larger application amounts, the rolling resistance becomes nearly 5 times greater.

Claims

1. A method of increasing the rolling wear resistance of a transportation floor panel, said panel comprising

-a multi-layer panel formed of-a plurality of wood veneers; and

wherein,

-prior to attaching the cover layer to the top veneer, impregnating the top veneer of the multilayer panel with a hydrophobic agent.

2. The method according to claim 1, wherein the hydrophobic agent is applied onto the top veneer from a composition containing the hydrophobic agent in an amount of 10-100 wt%, such as 60-100 wt%.

3. The method according to claim 1 or 2, wherein the hydrophobic agent is selected from the group of waxes, oils, fats, fatty acids, alkanes, alkenes, their derivatives and mixtures thereof.

4. A process according to any one of claims 1 to 3, wherein a paraffin, silicone oil or olefin ketene dimer is used as the hydrophobizing agent.

5. The method according to claim 4, wherein a paraffin or olefin ketene dimer is used as the hydrophobizing agent, said paraffin or olefin ketene dimer being used in solid form and being melted before or during application onto the top single sheet.

6. The method according to any one of the preceding claims, wherein the amount of the hydrophobic agent applied onto the surface of the wood panel is 20-100g/m²。

7. The method according to any one of the preceding claims, wherein the hydrophobic agent is applied onto the top veneer such that the wood fiber cavities are filled with hydrophobic agent.

8. The method according to any of the preceding claims, wherein said hydrophobic agent is applied onto said top veneer such that at least a portion of said hydrophobic agent will migrate from said top veneer to the next veneer therebelow.

9. The method according to any of the preceding claims, wherein said hydrophobic agent is applied onto said top veneer such that at least said top veneer and said veneer therebelow will be saturated with said hydrophobic agent.

10. The method according to any one of the preceding claims, wherein the cover layer comprises a layer having a rough surface, in particular the cover layer has a wire mesh patterned surface.

11. The method as set forth in any one of the preceding claims wherein the overcoat comprises a phenolic coating having about 100-300g/m²For example, 120-220g/m 2.

12. According to the preceding claimThe method of any of claims, wherein the phenolic coating layer comprises a paper substrate impregnated with a phenolic resin, the paper substrate having 40-80g/m²And has a grammage of 80-140g/m²A phenolic resin.

13. The method according to any one of the preceding claims, wherein the cover layer comprises a paper substrate impregnated with a phenolic resin, which cover layer has been applied on the surface of the top veneer of the multilayer panel by pressing, in particular by hot pressing.

14. The method according to any of the preceding claims, wherein the cover layer has been attached to the top veneer using hot pressing with a platen having a wire mesh patterned surface.

15. The method according to any one of the preceding claims, wherein the cover layer is attached to the top veneer using a phenolic resin, in particular a thermally activated phenolic resin, impregnated in a substrate such as a non-woven substrate.

16. The method of any preceding claim, wherein the panel is resistant up to 15kN/mm²Without the top veneer cracking, particularly any of the three top veneers.

17. A transportation floor panel obtained by the method according to any one of claims 1 to 16.

18. A transportation floor panel comprising a multi-layer panel formed from a plurality of wood veneers and a cover layer bonded to a top veneer of the panel and forming a surface of the panel, wherein

-said top veneer of said multilayer panel is impregnated with a hydrophobic agent; and

-the cover layer has a rough surface for enhancing friction between the surface of the cover layer and the roller.

19. A panel as claimed in claim 18, in which the overlay is formed from a phenolic coating layer having a first rough surface capable of facing the roller and an opposed second smooth surface.

20. A panel as claimed in claim 18 or 19, wherein the cover layer has a wire mesh patterned surface capable of facing the roller.

21. Panel according to any one of claims 18 to 20, wherein the cover layer comprises a paper substrate impregnated with a phenolic resin, the cover layer being applied on the surface of the top veneer of the multilayer panel by pressing, in particular by hot pressing.

22. The panel according to any one of claims 18 to 21, wherein the overlay has been attached to the top veneer using a hot press with a platen having a wire mesh patterned surface.

23. A panel according to any one of claims 18 to 22, wherein the overlay is attached to the top veneer using a phenolic resin, in particular a heat activated phenolic resin, impregnated in a substrate such as a non-woven substrate.

24. The panel according to any one of claims 18 to 23, wherein the hydrophobic agent is selected from the group of waxes, oils, fats, fatty acids, alkanes, alkenes, their derivatives and mixtures thereof, in particular paraffins, silicone oils and alkene ketene dimers.

25. The panel according to any one of claims 18 to 24, wherein at least the wood fiber cavities of the top veneer are filled with the hydrophobic agent.

26. A panel as claimed in any one of claims 18 to 25, which is resistant to up to 15kN/mm²Without the top veneer cracking, particularly any of the three top veneers.

27. A floor structure for a freight vehicle, comprising a frame and a floor formed from one or more transport floor panels attached to the frame, the panels comprising one or more panels according to any one of claims 18 to 26.

28. A floor structure according to claim 27, comprising a frame of a train wagon, a boat such as a ro-ro ship, a trailer, a cart or a truck.