JPS6225509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a laminate coated with a layer of lignocellulose material such as a wood material having a dense surface and excellent wear resistance, water resistance, etc.

Laminated materials, which are made by laminating wood materials on the surface of a base plate, are used in a wide range of applications such as furniture and construction materials. However, the conventionally used wooden materials have the drawbacks that their surfaces are easily damaged and that they are susceptible to expansion and contraction under the influence of moisture. For this reason, measures such as painting the surface of the wood material to protect it have been taken, but there have been no reports of success in improving the essential surface properties by modifying the components of the wood material itself. Furthermore, when conventional wood materials are used to create decorative materials by carving uneven patterns or embossed patterns on their surfaces by heat-pressing molding, the surface is susceptible to damage such as cracks. Due to its elasticity, the corners of the uneven pattern are rounded, making it difficult to obtain a sharp shape. This is because conventional wood materials have almost no thermoplastic properties. This also means that when trying to form a compact with a dense surface, harsh conditions (e.g. 250°C or higher, 20°C
Kg/cm ² or more), and such harsh conditions tend to cause carbonization and brittleness of the wood material.

As a result of intensive research in view of these problems, the present inventors have discovered that lignocellulose materials in the form of fibers, particles, sheets, etc., treated with a reactant that can react with the hydroxyl groups in the components, are placed on the surface of the base plate. If this is heat-pressed, a dense coating layer with excellent wear resistance and water resistance can be formed on the base plate.Furthermore, uneven patterns, embossed patterns, etc. can be created during heat-pressing. It has been found that when engraving, it is possible to form a molded product with a desired pattern with good reproducibility even under mild conditions.

The above-mentioned advantages can be obtained by the method of the present invention because thermoplasticity is imparted to lignocellulosic materials such as wood materials by chemically modifying the hydroxyl groups in the components. It is possible to avoid surface cracks during molding, and it is also possible to form sharp uneven patterns and embossed patterns.

That is, the present invention involves treating a lignocellulosic material with a reactant capable of reacting with hydroxyl groups to chemically modify the hydroxyl groups in the lignocellulosic material components;
The present invention relates to a method for producing a laminated material, which comprises disposing the thus obtained modified lignocellulose material on the surface of a base plate, and heat-pressing the material to form an integral laminated material.

As the lignocellulose material, wood materials such as fibrous, powder, flake, sheet, or lamellar materials that are used for the purpose of decorating and/or protecting the surface of the base plate can be used. , herbs, and other cellulose- and lignin-based materials can also be widely used.

In carrying out the invention, the lignocellulosic material is first treated by suitable means with a reactant capable of reacting with hydroxyl groups. Here, the reactant refers to a substance that chemically reacts with the components of the lignocellulose material, particularly the hydroxyl groups of cellulose, and representative examples thereof include esterification agents and etherification agents.

Esterifying agents include organic acid anhydrides (for example, acid anhydrides such as acetic acid, propionic acid, and butyric acid), organic acid halides (for example, in addition to the above acids, acid halides such as caproic acid, lauric acid, stearic acid, and methacrylic acid). and mixtures of organic acid anhydrides and fatty acids (for example, mixtures of trifluoroacetic anhydride or chloroacetic anhydride with acetic acid, propionic acid, caproic acid, lauric acid, etc.). These esterifying agents can be used alone or in combination of two or more.

The esterifying agent may include a catalyst such as sulfuric acid perchloric acid to promote the reaction with the components of the lignocellulosic material, and/or acetic acid toluene to promote the penetration of the esterifying agent into the lignocellulosic material. A solvent can be added.

Instead of or in addition to being added to the esterification agent, these catalysts and/or solvents may be impregnated in advance into the lignocellulose material before being treated with the esterification agent.

Next, as the etherification agent, for example, 1.2 epoxides such as ethylene oxide and propylene oxide, alkyl halides such as methyl chloride and ethyl chloride, and aromatic halides such as benzyl chloride can be used.

In the case of an etherification agent, as in the case of an esterification agent, a catalyst (for example, an alkaline catalyst such as sodium hydroxide) and a solvent (for example, a solvent similar to that used in the case of an esterification agent) may be appropriately added. It is also possible to pre-impregnate the ribnocellulose material before treatment with the etherification agent, although the latter is particularly preferred in the case of catalysts.

In addition to the above-mentioned esterifying agents and etherifying agents, examples of reactants capable of reacting with hydroxyl groups include isocyanates (eg, methyl isocyanate, ethyl isocyanate, etc.).

The reactant can be contacted with the lignocellulosic material by, for example, immersing the lignocellulosic material in the reactant or by vaporizing the reactant and exposing the lignocellulosic material. Further, such a method can be carried out under reduced pressure, under increased pressure, or by a reduced pressure method to promote impregnation of the reactant into the lignocellulosic material.

Through chemical treatment with such reactants, the components of the lignocellulosic material, particularly the hydroxyl groups of cellulose, undergo chemical modifications such as esterification and etherification, and the crystalline structure of cellulose becomes amorphous, thus changing its thermoplastic properties. A lignocellulose material is obtained.

The lignocellulose material modified by the above operation is placed on the base plate by scattering or placing. In this case, a suitable adhesive may be applied to the base plate in order to ensure that the lignocellulose material and the base plate are bonded together, and the lignocellulose materials may be bonded to each other and to the base plate. The lignocellulosic material may be mixed with or impregnated with an adhesive to improve the adhesive properties.

It is suitable for the baseboard to be made of wood materials such as wood fiberboard, plywood, particle board, etc., but depending on the heat pressing conditions described below, various materials such as asbestos cement board, metal board, synthetic resin board etc. can be used. Of course, other materials can be used, and the shape of the laminated surface is not limited to a flat surface or a curved surface, but may have various uneven patterns.

After placing the modified lignocellulose material on the base plate, it is heated and pressed. Through this heat compression molding, the lignocellulose material placed on the base plate is densified due to its thermoplastic properties, and is easily molded to follow the shape of the base plate.
It is laminated and integrated with the base plate.

The heating and pressing conditions are set appropriately depending on the type of reactant used, the degree of amorphization, etc., but usually 80~
It can be carried out under relatively mild conditions such as a temperature of 250° C. and a pressure of 2 kg/cm ² or more.

In addition, when heat-pressing, a mold material whose shape roughly corresponds to the shape of the laminated surface of the bed plate is usually used.
It is also possible to use these molded materials which are further engraved with an uneven pattern or an embossed pattern that does not exist on the base plate. In this case, the lignocellulose material layer can be engraved with an uneven embossed pattern depending on the mold material, but as mentioned above, the lignocellulose material according to the present invention has thermoplastic properties, so it is extremely reproducible. These patterns can be engraved with ease.

The characteristics of the method of the present invention and the laminate obtained by the method of the present invention are listed below.

(1) The surface of the base plate is coated with a modified dense lignocellulose material, making it less susceptible to damage such as wear and scratches.

(2) The modified lignocellulose material does not easily swell or undergo deformation such as warping even when exposed to water or humidity, resulting in a laminated material with excellent moisture and water resistance.

(3) Since the modified lignocellulose material has thermoplastic properties, it has good moldability, and a laminate material with an arbitrary surface shape can be obtained.

(4) For the same reason as above, it can be formed under relatively gentle heating and pressing conditions, and therefore carbonization and brittleness of lignocellulose materials such as wood can be avoided.

Hereinafter, specific embodiments of the present invention will be described in detail based on the drawings.

Example 1 Wood fibers obtained by defibrating wood with a pulper etc. were pretreated by immersing them in a mixed solution consisting of 5 parts of acetic anhydride and 30 parts of glacial acetic acid for 2 hours, followed by 20 parts of acetic anhydride. The wood fibers are immersed for 4 hours in a treatment solution consisting of 5 parts of glacial acetic acid and 0-1 part of perchloric acid to carry out an esterification (acetylation) reaction, then washed and dried to chemically convert the hydroxyl groups in the wood fibers. A modified wood fiber a was obtained.

This wood fiber a is a semi-hard fiber obtained by cutting a frame-shaped decorative groove 2 with a depth of 5 mm in the center of the surface and a curved decorative surface 3 on the peripheral part of the surface by cutting the wood fiber a as shown in FIG. 1a. After applying the adhesive to the entire surface of the plate base plate 1, it was spread and deposited as shown in FIG. 1b.

Next, the base plate 1 on which the wood fibers a have been scattered and deposited has an uneven shape that approximately corresponds to the uneven surface shape of the base plate 1, and a fine embossed pattern in the shape of wood grain (not shown) is formed on the uneven surface. ) was heated and pressed for 5 minutes at 180° C. and 10 kg/cm ² to obtain a laminate 5.

The surface of the thus obtained laminated material 5 is covered with a dense wood fiber layer a', making it less susceptible to damage due to abrasion, etc., and the uneven shape of the profile and the wood grain-like embossed pattern provided on the uneven surface. Both were reprinted with good reproducibility and had excellent cosmetic properties.

[Brief explanation of the drawing]

FIGS. 1A to 1D are cross-sectional views of the manufacturing process of the laminated material. DESCRIPTION OF SYMBOLS 1... Base plate, 2... Edge-shaped decorative groove, 3... Curved decorative surface, 4... Shaped material, 5... Laminated material, a... Wood fiber, a'... Wood fiber layer.

Claims (1)

[Scope of Claims] 1. Treating a lignocellulosic material with a reactant capable of reacting with hydroxyl groups to chemically modify the hydroxyl groups in the lignocellulosic material component, and using the thus obtained modified lignocellulosic material as a base plate. A method for manufacturing a laminated material, characterized by placing it on the surface and heat-pressing it to integrate the laminated material. 2. The method of manufacturing a laminated material according to claim 1, wherein a mold material having a shape substantially corresponding to the surface shape of the base plate is heat-pressed. 3. The method for manufacturing a laminated material according to claim 2, which uses a shape material having an uneven pattern or an embossed pattern carved thereon that does not exist on the base plate.