WO2004022334A1

WO2004022334A1 - Composite veneer and method of manufacturing thereof

Info

Publication number: WO2004022334A1
Application number: PCT/VN2003/000002
Authority: WO
Inventors: Trong Son Lam
Original assignee: Trong Son Lam
Priority date: 2002-09-03
Filing date: 2003-09-03
Publication date: 2004-03-18
Also published as: AU2003273379A1

Abstract

The invention relates to a composite veneer in the form of flooring bricks comprising a veneer (1) in combination with a solid base (2), the new material formed thereby has the aesthetic features equivalent to that of rare and precious wood and at the same time the durability much higher than both natural and artificial wood as well as the ceramic materials of the same functions. The preeminence of the material according to the invention is high durability and hardness while retaining the unique beauty of precious and rare wood. The invention also relates to a method of combining the grains of precious wood of various kinds into plywood, opening an indefinite future for indoor decoration. The invention also relates to the manufacture of the aforementioned composite veneer in the forms of bricks for flooring, facing or paving walls and ceilings.

Description

Composite veneer and method of manufacturing thereof Field of the invention:

The invention relates to construction materials, particularly wood-substitutes, more particularly to a composite veneer with high durability and stability against strong impacts from the external environment yet retaining tlie aesthetic features of natural wood. More paiticulaiiy, tlie invention relates to tlie veneer in which tlie veneer surface is combined with a base material and a coating material of high durability. Background of the invention

The shortage of resources of high-quality wood of low deformability, high hardness and high resistance to woodworms and rot has been pushing up the prices to veiy high levels. In response of the exorbitant prices, a common measure is utilizing thick cheap planks of low quality for prevention of dimensional changes and at the same time wood of high quality as a damp-proof layer. A house with floors and walls made of wood, particularly wood of high class, is however still luxury, not to say impossible to build because of financial causes.

Many attempts have been made manufacturing wood-substitutes from cheaper raw materials. For instance, plywood, graft-wood and cheap wood processed, painted or coated with synthetic materials. In general, those wood-substitutes can be employed for making indoor decorations yet they are not suitable for flooring because during use, floors should be rigid, and particularly have low dimensional expansion and at the same time high resistance under wet conditions.

In the environment of high humidity, plywood easily adsorbs moisture, expanding then taming the floor to be arched. Then a blistered wood easily cracks under forces. The blistering is faster when a user carelessly drops water on plywood. The plywood coated with polymer is still not damp-proof because after a short time in use, moisture still gets contact with plywood through the gaps that exist during the coating process.

The plywood having a polymer cover (varnished boards) has higher resistance to moisture but its hardness is limited because the polymer coat may create cracks or crevices at some points during use, through which moisture can penetrate and destroy the material. Other kinds of graft boards made of rubber wood have higher resistance and are tlierefore suitable for flooring. Nevertheless, this material needs complicated manufacturing technology and equipment for treatment of boards before grafting. Another solution is to use flooring sheets made of a polymer or copolymers or the like, on which wood-imitating fibers are printed. Nevertheless, tlie lifetime of the products in accordance with this solution is usually short because the moisture in concrete causes the flooring sheets to adhere poorly thereunto. Besides, the concrete surface should be such leveled that the floor meets requirement of flatness after being tiled with the flooring sheets.

In tlie world there are many attempts to turn out wood having high resistance and at the same time having aesthetic and durable faces. One of progress trends is to use veneers, which are the thinly sliced wood.

A flooring veenr is found in US Patent 3,055,065, in which the veneer is thoroughly dried then bound with the hard base by mean of adhesive under high pressure in a short time. Besides, the veneer including two layers, which are separated each other by numerous fissures along the grain, the two layers are arranged with the average angle of fissures of two layers in the range of 3 to 20 decrees so as to get over the problem of blistering because of moisture.

Another flooring veneer is found in US Patent Application 2002 064 622, in which the base composes of many wood layers bound together such that the grain of the upper layer is perpendicular to that of the adjacent lower layer, the layers having fissures or holes along the grains and the veneer is a thin layer bound on the base. This patent application also provides multi-ply wood, in which the core ply is tlie material selected from the group consisting of plywood, chip board, particle board, masonry or plastics. Nevertheless, one of tlie countermeasures for prevention of deformation is longitudinally pierced fissures formed in parallel with the longitudinal grains structures, those, in the one hand, improve tlie binding among plies, and at the same time, offset tlie expansion of wood.

Thus, tlie prior arts arrange the grain structure in determined directions, usually perpendicularly or diagonally so as to make up the expansion and diffuse the external forces to parallel and perpendicular directions of the grain structures between layers so s > <aι vω (- dn» 3 as to increase the strength of the surface veneers. Such materials cannot meet the basic requirements of flooring such as high strength and particularly resistance to a wet environment.

The invention relates to a composite veneer with a simple method of manufacture, and paiticulaiiy that has not only hardness substantially higher than any kind of wood but also grains of valuable wood. Summary of the invention:

There is an object of the present invention to provide a new composite wood material of high resistance to moisture, woodworms and impacts caused by weather and climate in general, durability to external physical and chemical factors. It is another object of tlie present invention to combine the best characteristics of natural wood such as high durability and stability to environmental impacts with the characteristics of hard base materials.

It is another important object of the present invention to provide a material to bind the surface veneer with the hard solid base layer.

It is still another object of the present invention to provide a simple method for fabricating the composite veneer of improved characteristics.

The invention reaches the aforementioned objects by binding a layer of sliced natural wood with a base of suitable materials through an immediate binding layer. On manufacturing composite materials, die problem is how to bind layers of various materials. The usual way of consolidating the binding among materials is using an adhesive to be hardened at elevated temperature and at the same time, imposing high pressure on the two layers to be bound so as to accelerate the penetration of the adhesive into the microscopic pores on the surface of tlie materials. As for wood- substitutes, the binding at elevated temperature and high pressure requires complicated and bulky machines. The invention renders a solution for binding wood and base materials such as concrete and composite plastics by means of epoxy adhesives usually in construction. Besides, the manufacture according to the invention simplifies equipment by means of production composite material blocks with dimensions of tiling bricks. For maximizing the durability to environmental factors, the invention provides for coating the veneer surfaces with polymers of high durability.

Brief description of drawings

The present invention will become readily apparent to those skilled in the art from the following description with reference to illustrated drawings, wherein:

FIG. 1 is a perspective view of the layer structure of the composite flooring according to tlie present invention;

FIG. 2 is a flow diagram of a process for making a composite flooring according to the present invention.

Detailed description of the preferred embodiment

Reference is made to FIG. 1, the composite veneer wood according to the present invention comprises four layers: a veneer surface layer 1, a base layer 2 and an intermediate 3 amid the veneer surface layer 1 and the base layer 2, and a surface coating layer 4. hi a preferred embodiment of the present invention, the veneer surface layer is 0.8 -

1.2 mm thick, is natural wood of classes 1 to 5 according to the Wood Classification of the Forestation Administration, for instance Plerocarpus pedalus pierre, Cupressis funebris endl, Afzelia Xylocarpa (Kurz), and Caesalpiniacere (Robx), etc.

The strength of the material according to the present invention is created by the base layer 2, which is a concrete block made from cement, sand, and pebble, etc. in suitable proportion being calculated by the method known per se in the construction field. The base layer is also made of other kinds of concrete such as soft concrete and light and spongy concrete to reduce the density of the product. Furthermore, the base layer can be made of composite materials, for instance, a mixture of asbestos fiber and polymer adhesive, glass cotton and polymer adhesive, etc.

The intermediate layer 3 is functioned for binding the base layer 2 and the veneer layer 1. It is a layer of epoxy known per se in construction. In a preferred embodiment, the intermediate layer 3 comprises a multiple of adhesive layers, wherein tlie damp-proof adhesive layer is first applied to the surface of tlie concrete base layer, then the concrete-bindmg adhesive layer is applied to the damp-proof adhesive layer and finally a layer of adhesive binding the veneer with the base previously coated with said adhesive layers.

During use, in addition to binding closely the veneer layer 1 on the surface and the base layer 2 beneath, tlie intermediate layer 3 also plays tlie role of prevention of moisture penetration from tlie wood surface to the concrete base.

In addition to the usually binding function, tlie intermediate layer also plays the role of a bed neutralizing the plastic deformation for the veneer layer and at the same time, isolating tlie wood layer from direct contact with and thereby damage due to the hard surface of the base layer. Furthermore, the layer of adhesives prevents moisture from contact with the lower surface of the veneer layer, thereby improves the capability of prevention of moisture from returning to the material according to the present invention.

The surface coating layer 4 is made of a transparent, hard and lustrous and durable material. In a prefened embodiment, tlie surface-coating layer is made of polyurethane.

The polyurethane coating layer 4 helps the material according to the present invention not to contact with moisture, thereby avoiding the swelling under tlie impacts of environmental factors. Furthermore, thanks to high rigidity and resistance, the polyurethane coating layer provides the material according to the present invention with characteristics such as excellent resistance to scratch, chemicals, fire and an extremely high glossiness as well.

In another prefened embodiment, for higher hardness and sharpness of the surface of the base layer, the upper smface (to be coated with the intermediate layer) is made of high-grade concrete, for instance the concrete from white cement or stone dust.

Besides, reinforcing veins known per se can also be provided on the lower surface of tlie base layer.

An advantage of the composite veneer product according to the present invention is that its basic quality parameters are substantially higher than those of the materials of the same functions known so far are. That is apparent with quality parameters shown in Table 1 below. Table 1: Quality comparison of materials and tlie composite veneer according to the present invention

Another preeminence of the present invention results from combination . of natural wood and artificial materials. In recent years and in the future, many new matter of construction with higher hardness and lower density, etc. have and will come into being. All of them can similarly combine with natural wood and make it possible to fabricate numerous products of higher quality at lower production cost. Composite veneer products with dimension of floorings can be employed for all known purposes of ceramic materials. A characteristic that the material according to the present invention is superior to ceramic bricks and tiles with unique patterns of wood and indefimte variations of shapes from veneer.

In another prefened embodiment, the veneer layer is a multiple of pieces of ^j predetermined shapes that create the design thereof. That enables an indefinite capability for making products of unique decorative designs including pictures formed by pieces of wood. And the thinness of the veneer makes it possible to cut into various designs or unique shapes at users' and clients' request.

Reference is now made to FIG. 2., in a prefened embodiment of the present invention, the manufacture of the composite veneer comprises the steps of slicing, drying, cutting, surface-treating, adhesive-applying, forming, hot pressing and coating. Natural wood is sliced to veneer having thickness of between 0.8 mm and 1.2 mm by means of slicing machines known per se in the wood-processing industry. Depending on tlie type of natural wood, particularly its strain structure and microscopic pores inside, logs are sliced along their strain structures so as to get the nicest patterns. Thinly sliced wood is dried until its moisture is lower than or equal to 12 percent in conventional dryers. Since wood is dried after slicing, the drying time is shortened and consequently the production cost is reduced.

Dried slices are cut into pieces either with dimensions of the end-use tiling bricks or wood or predetermined shapes for making the designs of the end-use wood-substitute. Before cutting, the veneers can be sewn with each other by means of conventional veneer-sewing machines, then pressed and undergone mechanical or manual surface treatment and finally the veneers have close-fitting surfaces.

Independent to the preparation of the veneer smface is tlie preparation of the base layer. Materials such as cement, sand and macadam with appropriate ratios are mixed and solidified in molds of predetermined dimensions and resulted in inteπnediate products with the shapes and dimensions substantially similar with the end products. It is possible to employ conventional measures for improving the hardness, sharpness and flatness of the surface that contacts with the intermediate layer. For instance, high-grade cement or concrete made from materials such as white cement and stone dust mixed at a ratio known per se in production of tiling bricks to create a mortar, then filling to molds first the mortar and second the material for a usual base layer. The materials in molds are thereafter pressed with pressing machines usually used in production of tiling bricks, and as a result, parts of the two materials are mixed foiTuing united blocks. hi another prefened embodiment, the base layer has the structure of ceramic tiling brick without glaze.

After drying, tlie intermediate products are coated with the inteπnediate layer. One advantage of tlie method according to the present invention is that layers of adhesives are applied to the surface of the intermediate products in an industrial process with each adhesive dried and solidified under stringent control. It is therefore possible to utilize various adhesives of different nature and solvent yet the bindings are still strong and stable.

After being coated with tl e intermediate layer, the intermediate product is put in forming molds, wherein the veneer of predetermined shapes from the cutting step are pasted on tlie adhesive-coated face of the inteπnediate products then the bound blocks are pressed at elevated temperature! In the step of pressing at elevated temperature, layers of adhesives in the intermediate layer mix together and penetrate microscopic pores of both wood and concrete, and creating a blocks strongly bound after solidification.

The step of pressing at elevated temperature is canϊed out in conventional hydraulic hot-pressing machines with the pressing temperature of between 90 - 100°C and a pressing force of approximately 30 metric ton for the products having conventional dimensions such as 50 x 50 cm.

After being pressed at elevated temperature, tlie veneer surface is polished to be flat and glossy by means of polishing machines known per se.

Finally, the wood surface is coated with a polyurethane layer.

In another prefened embodiment, polyurethane is applied to the surface of the composite veneer according to the present invention after the bricks are tiled.

Although the dimensions of the tiling sheets are dependent on the dimension of the equipment, in general with suitable equipment, it is possible to fabricate composite veneer sheets of any dimensions.

Nevertheless, in a prefened embodiment, the composite veneer according to tlie present invention is fabricated having the dimension equal to that of flooring bricks.

As such, anotlier advantage of tlie metliod of manufactme accordmg to the present invention is resulted from tlie utilization of 'comparatively small pressing machines which enable affordable initial investment and low production cost.

An advantage of the composite veneer according to the present invention is the use of natural wood, particularly precious ones, in an economic and effective manner. That is apparent with the calculation as follows:

1 m³ of wood can provide at most 33 m² of flooring boards having thickness of 3 cm. whereas, if tlie same volume is put into production of the material according to the present invention, 1,000 m² of flooring material in which the veneer having thickness of approximately 1 mm is used.

Anotlier advantage of the present invention is to make full use of natural wood log because the percentage of useless slab is low as a result of slicing of wood. It is experienced that 1 cubic meter of log gives only 27 m² of flooring bpards having thickness of 3 mm, meaning that 20 percent of wood become useless as slab. Comparatively, 1 m³ of log turns out approximately 1,000 m² of veneer having thickness of 1 mm, i.e. 1,000 m² of the flooring material according to the present invention.

As a result of adhesion under industrial production wherein conditions such as moisture of concrete, percentage of adhesives, adhesion pressure and temperature, etc. are optionally monitored and controlled, tlie products according to tlie present invention have resistance and consistency of quality superior to products of similar functions such as rubberized cloth, waterproof water adhered on wood, varnished boards, etc. which are the products of the productions wherein the adliesion is almost not subject to strict control.

Claims

1. A composite veneer combining a veneer surface and a hard base, comprising four layers: a veneer smface layer, a base layer, a medium layer interposing and adhering the veneer surface and the base, and a coating layer.

2. The composite veneer as claimed in claim 1, wherein the medium layer being a combination of adhesive materials.

3. The composite veneer as claimed in claim 2, wherein the veneer smface being the veneer of precious and rare wood.

4. The composite veneer as claimed in any of claims 1 to 3, wherein the veneer smface comprising a plurality of thin layers being cut in predefined shapes and aπanged so as to form various decorative designs.

5. The composite veneer as claimed in any of claims 1 to 4, wherein the base layer being selected from the group consisting of normal, light and spongy concrete.

6. The composite veneer as claimed in any of claims 1 to 4, wherein the base layer being a composite material made from synthetic fiber and polymer adhesive.

7. The composite veneer as claimed in any of claims 1 to 4, wherein tlie base layer being made from white asbestos fiber and epoxy adhesive.

8. The composite veneer as claimed in any of claims 1 to 4, wherein the matter of construction of the base layer being ceramic without glaze.

9. The composite veneer as claimed in any of claims 1 to 8, wherein the coating layer being made of polyurethane.

10. The composite veneer as claimed in claim 8, wherein the polyiirethane coating layer being coated after the material is put into the ready-to-use state.

11. A method of manufacture of the composite veneer as claim in claim 9, comprising: drying, slicing, cutting, surface-treating, adhesive-applying, forming, hot pressing, coating.

12. A method as claimed in claim 11, wherein the composite veneer products having the dimension of flooring bricks.

13. A method as claimed in claim 12, wherein tlie coating being canied out after the composite veneer products are tiled on a floor or a wall.