JPS6247686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to a method for producing decorative materials with excellent decorative properties, and more specifically, to
A method for producing decorative materials with particularly excellent decorative properties, which comprises chemically treating cellulose crystals with a reactant capable of reacting with the hydroxyl groups of wood components until they become amorphous, such as an etherifying agent, and then heating and pressing them. Regarding.

Conventional methods for strengthening thin wood boards and improving their decorative properties include coating the surface of thin wood boards with synthetic resin paint to form a transparent film, and filling voids such as conduits in thin wood boards with synthetic resin and hardening. There is a known method of forming the material into a decorative material. However, with the former method, it is possible to strengthen the protection of the surface of the thin wood board and add some transparency by partially impregnating it with synthetic resin paint to improve its decorativeness, but the It is difficult to provide enough transparency to create a noticeable contrast between the two, and since the cell structure of the wood laminate remains intact, it is difficult to create a new wood grain appearance by changing the grain of the original wood lamina. It was impossible to form.

On the other hand, in the latter method, the synthetic resin is filled and hardened into the voids in the conduits of thin wood boards, especially the voids in the spring wood, resulting in high transparency and a marked contrast between the spring wood and fall wood. Although it can be formed into a deep appearance, it has the problem that the thin wood boards themselves have a wide variety of texture structures, making it easy for uneven filling of the synthetic resin to occur. It has not been possible to change the grain of wood sheets to create new grain appearances.

The present inventors chemically treated thin wood boards with reactants (hereinafter simply referred to as reactants) that can react with hydroxyl groups in wood components, such as esterification agents and etherification agents, to mainly remove cellulose, a wood component. The present inventors have discovered that by heat-pressing the material after it has been amorphized, effects that could not be achieved with the prior art can be obtained, leading to the completion of the present invention. That is, according to the method of the present invention, it is possible to impart a highly transparent and deep appearance to wood, and it is also possible to change the original wood grain pattern to form a new wood grain pattern, thus significantly improving decorativeness. It is possible to obtain decorative materials. Furthermore, the decorative material obtained by the method of the present invention has excellent physical properties, such as being able to be molded into a three-dimensional shape such as a curved surface.

As mentioned above, the method of the present invention includes the steps of chemically treating the wood laminate with a reactant (step 1) and heating and pressing the wood thus treated (step 2).
Consisting of Each stage is explained in detail below.

In the first step, the hydroxyl groups of the wood components, particularly cellulose, are chemically modified by contacting the wood veneer with the reactants by suitable means to amorphize the crystalline structure of the cellulose.

There are no particular restrictions on the species or shape of the wood that can be used. However, regarding the shape, a thin plate of about 0.3 to 10 mm is preferable from the viewpoints of ease of treatment with reactants, high productivity, and high utility value as a decorative material as a finished product.

As mentioned above, the term "reactant" refers to a substance that chemically reacts with the hydroxyl groups of wood components, particularly cellulose, and representative examples thereof include esterifying agents and etherifying 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 anhydrides and fatty acids (for example mixtures of trifluoroacetic anhydride or chloroacetic anhydride with acetic acid, propionic acid, caproic acid or lauric acid, etc.). These esterifying agents can be used alone or in combination of two or more.

A catalyst for promoting the reaction with the wood component and/or a solvent for promoting the penetration of the esterifying agent into the wood cell membrane can be added to the esterifying agent. Such catalysts include sulfuric acid, perchloric acid, urea-ammonium sulfate, zinc chloride, and pyridine, and solvents include acetic acid, benzene,
Examples include toluene, dimethylformamide and dinitrogen tetroxide-dimethylformamide, and two or more of each may be used as a mixture.

Instead of or in addition to being added to the esterifying agent, these catalysts and/or solvents may be impregnated in advance into the wood before being treated with the esterifying 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, aromatic halides such as benzyl chloride, dialkyl sulfates such as dimethyl sulfate, monochlor α-halogen acids such as acetic acid, vinyl compounds activated with negative groups such as vinyl cyanide, aldehydes such as formaldehyde, etc. 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 wood with the etherifying agent before treating it.
In the case of catalysts, the latter is particularly preferred.

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 reactants can be brought into contact with the wood sheets by, for example, immersing the wood in the reactants or by vaporizing the reactants and exposing the wood to this. Further, such a method can be carried out under reduced pressure, increased pressure, or a reduced pressure method to promote impregnation of the reactant into the wood. The contact time between the reactant and the wood varies depending on the above-mentioned treatment conditions, but when the treatment is carried out at normal temperature and pressure, about 1 to 10 hours is usually sufficient.

Through chemical treatment with such reactants, wood components, especially the hydroxyl groups of cellulose, undergo chemical modifications such as esterification and etherification, and the crystalline structure of cellulose becomes amorphous, resulting in wood in a swollen state. (hereinafter referred to as treated wood) is obtained.
At this time, the hydroxyl groups of hemicellulose and lignin, which are the main components of wood along with cellulose, may also undergo similar chemical changes, and in this case, the bonds between wood components are weakened, and the degree of swelling of the wood becomes even more significant.

The degree of amorphization and swelling can be adjusted as appropriate depending on the type of reactant and treatment time, but in general, tissues with large voids such as ducts and tracheids and with thin cell membranes are generally used. The spring wood is more easily impregnated with reactants than the fall wood, and therefore amorphization and swelling are more pronounced than in the fall wood, which leads to the formation of new wood grains, as described below. It is presumed that this is a contributing factor.

The thin wood board chemically treated in the first step is subjected to a second heat pressing treatment.

The heat pressing conditions are appropriately set depending on the type of reactant used, the degree of amorphization and swelling, etc., and are not particularly limited.
℃ temperature and pressure of 10Kg to 200Kg/ ^cm2 within 30 minutes without causing thermal deterioration of wood.
The object of the present invention can be satisfactorily achieved.

This heat-pressing process makes the treated wood denser and more transparent without causing breakage or deterioration, and it also causes changes such as expansion of annual rings, especially in the spring wood, resulting in subtle differences from the original wood. A vine wood grain is formed, and the imparted transparency and the newly formed wood grain combine to form a decorative material having a new wood grain appearance rich in depth and decorativeness.

In addition, the obtained decorative material is densified without causing any deterioration of the wood itself, so it has excellent physical properties such as high wear resistance and flexibility. Even when the wood grain of the thin plate is irregular or a wood grain pattern is placed on the surface, the added flexibility makes it difficult to cause damage such as cracking, and it has excellent crack resistance.

Note that the treated wood may be colored in advance with a fluorescent colorant or any other coloring agent before heat-pressing. In this case, since the treated wood is amorphous and swollen, the coloring liquid penetrates easily and uniformly, and after heat-pressing, it becomes even deeper due to the added transparency. It can be finished with a wood grain appearance rich in elegance and elegance, and its decorative value can be further improved.

In addition, when heat-pressing, it is also possible to form a laminate by laminating multiple pieces of treated wood, or by stacking a base plate such as plywood and treated wood and heat-pressing them. .

The reason why the above-mentioned new wood grain pattern can be imparted to wood will be discussed in more detail below with reference to the attached drawings.

FIG. 1 is a schematic cross-sectional view of wood that has been chemically treated in the first step of the method of the present invention, that is, treated wood a and decorative material b obtained by heating and compressing it. Treated wood a has undergone chemical changes (amorphization due to esterification of hydroxyl groups, etherification, etc.) and structural changes (swelling) as a result of chemical treatment with reactants, and has a thermoplastic property compared to the original wood. rich in Therefore, the wood can fill the void A without causing damage or deterioration.
It is compressed and flattened in . In this way, the densified treated wood reduces the amount of light scattered in the voids A,
Light transmission is therefore increased.

Similar to FIG. 1, FIG. 2 is a schematic cross-sectional view of treated wood a and decorative material b obtained by heat compression.
The spring wood and autumn wood are depicted more macroscopically so that you can compare them. Spring wood parts with many voids due to conduits, tracheids, etc. have a high degree of amorphization and swelling, and are highly deformed due to compression and densification, so the annual ring width of treated wood a.
W ₁ is expanded to W ₂ in decorative material b obtained after heating and compression. This change in growth ring width creates a new wood grain appearance.

In the heat-pressing process, the treated wood can be melted or partially melted by appropriately setting the conditions for treating the wood with the treatment solution and the heat-pressing conditions.

When this melting occurs, the density is further improved, resulting in a decorative material that has high transparency and a more varied wood grain appearance, and has excellent physical properties such as abrasion resistance and crack resistance. Obtainable.

Further, during heat-pressing, a mold material having an appropriately shaped pressing surface such as a curved surface or a U-shape may be used. In this case, since the treated wood has thermoplastic properties, decorative materials formed into three-dimensional shapes such as curved or bent shapes can be formed with good moldability without creating defects such as cracks. It is something that can be done.

Similarly, when a molded material with an appropriate embossed pattern, such as a conduit structure pattern, is heated and pressed, the embossed pattern can be applied very easily and favorably. Even without using a mold material, it is possible to form a concave embossed pattern in which the autumn material part is convex and the spring material part is concave by heat-pressing through the cushion material.

As mentioned above, the decorative material obtained by the method of the present invention has outstanding decorative properties, and at the same time has excellent physical properties such as abrasion resistance and crack resistance. Since it can be easily formed on the body, it can be used not only as a decorative surface material for building materials, furniture materials, etc., but also for a wider range of applications.

The present invention will be explained in more detail with reference to Examples below.

Example 1 A spruce veneer with a thickness of 1 mm and a size of 10 cm x 10 cm was placed in a mixture of 4 ml of acetic anhydride and 30 ml of glacial acetic acid.
After pretreatment by immersion for an hour, the esterification (acetylation) reaction was carried out by immersion in a treatment solution maintained at 30°C consisting of 20 ml of acetic anhydride, 6 ml of glacial acetic acid, 7 ml of toluene, and 0.1 ml of perchloric acid for 4 hours. After doing it,
In a solution consisting of 50 ml of glacial acetic acid and 0.3 g of potassium acetate.
It was immersed for 20 minutes and washed with toluene to obtain an acetylated veneer. Weight gain rate due to acetylation: 40%.

The treated veneer was then heated and compressed at 180° C. and 30 kg/cm ² for 10 minutes to obtain a decorative material.

Compared to the veneer before treatment, the resulting decorative material has a wider grain width in the spring wood portion and a narrower grain width in the fall wood portion, thereby exhibiting a new wood grain pattern. On the other hand, when the light transmittance was measured based on JISK-6714, the transmittance was 30%.

As a comparative example, the same spruce veneer as above was heated and pressed under the same conditions as above without being treated with a treatment solution, and no change in wood grain was observed and the result was JISK-6714. The light transmittance was 3%.

Example 2 The acetylated veneer obtained in Example 1 was
The acid dye heated to 180°C was immersed in a coloring solution consisting of a 1% acid orange aqueous solution for 3 hours, and after coloring, it was heated and pressed at 180°C and 30 kg/cm ² for 10 minutes. The obtained decorative material had a transparent orange color in the spring wood portion, was uniformly colored to the inside of the wood structure, and had an appearance with excellent decorative properties.

As a comparative example, the untreated veneer used in Example 1 was immersed in the above-mentioned coloring liquid under the same conditions to be colored, and then heat-pressed under the same conditions as above.
The obtained veneer had only the surface layer colored, had no transparency, and was inferior in decorativeness.

Example 3 White×BK instead of acid orange
The same operation as in Example 2 was performed except that CONC (manufactured by Sumitomo Chemical Co., Ltd.) was used.

The obtained decorative material was not only highly transparent and had a varied wood grain pattern, but also had an elegant, fluorescent appearance.

Example 4 The acetylated veneer obtained in Example 1 was inserted between male and female molds each having a round shaped molding part with a radius of curvature of 10R at the corner and heated at 180°C and 30Kg/ ^cm2 for 10 minutes. A square-shaped decorative material was obtained by heating and pressing. This decorative material had no defects such as cracks, was highly transparent, and had a beautiful decorative surface with a changed wood grain appearance.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are both schematic cross-sectional views of treated wood a and decorative material b. A...Void area, L...Light, _W1 and _W2 ...annual ring width, _α1 and _α2 ...annual ring inclination, F...autumn wood area, S...spring wood area.

Claims (1)

[Claims] 1. Treating the wood laminate with a reactant capable of reacting with the hydroxyl groups of wood components until the cellulose crystals in the wood laminate are amorphized, and heat-pressing the resulting treated laminate. A method for producing a decorative material consisting of: 2. The method for producing a cosmetic agent according to claim 1, wherein the reactant is an esterifying agent or an etherifying agent.