JPH0929711A - Pretreating method for timber and manufacture of modified timber using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give excellent modifying effect to a timber by sufficiently and uniformly impregnating the timber with a desired modifying liquid in a short time. SOLUTION: A treated timber provided with brittleness by acetalizing timber is sealed with a liquidproof sheet. Then, it is dipped in a liquid-like pressurized medium and pressurized to cause many fine cracks to occur in timber tissue. Then, the thus pretreated timber is impregnated with a modifying liquid made of a synthetic resin and cured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to wood for abrasion resistance,
The present invention relates to a wood pretreatment method for imparting hardness, water resistance, dimensional stability, stain resistance, decorativeness, etc., and a modified wood production method using the same.

[0002]

Conventionally, the abrasion resistance of wood has been improved by impregnating wood with synthetic resin liquid such as phenol resin, vinyl resin, unsaturated polyester resin, etc. and curing it. , Improve hardness, water resistance, etc.
Alternatively, it is widely known that wood is impregnated and fixed with a liquid antiseptic agent and a fireproof agent to impart antiseptic property and fireproof property.

However, according to this method, when it is attempted to impregnate the wood with the above-mentioned modified treatment liquid such as the synthetic resin liquid, the well-known forced injection method such as the depressurizing method, the pressurizing method, and the depressurizing pressurizing method is utilized. Also, due to the shape and type of the wood or the viscosity of the modification treatment liquid, the amount of impregnation is insufficient, or the desired modification effect cannot be obtained due to uneven impregnation of the modification treatment liquid. Sometimes deteriorated the appearance. Even with the above-mentioned forced injection method, the impregnation process took a long time and the productivity was low.

Therefore, in order to enhance the impregnation property of the modifying liquid, a method is proposed in which wood is preliminarily pressed with a press or the like to cause fine cracks in the wood structure and then impregnated with the modifying liquid. Has been done.

However, the degree of brittleness of wood against pressure is easily affected by the tree species, shape (particularly, thickness), water content, etc. of wood, and variations in the generation of fine cracks are likely to occur. For this reason, for example, when the pressure-treated wood is impregnated with the synthetic resin liquid by a simple dipping method, unevenness of impregnation occurs and the appearance of the wood is deteriorated.

In view of the above problems, an object of the present invention is to provide a desired modifying treatment liquid to the wood sufficiently and uniformly in a short time, thereby providing the wood with a good modifying effect. It is to provide a pretreatment method and a method for producing modified wood using the same.

[0007]

In order to achieve the above-mentioned object, the method for pretreating wood according to claim 1 pressurizes the treated wood with brittleness obtained by acetalizing wood and presses the wood. This is a process of producing many fine cracks in the structure.

According to a second aspect of the present invention, the method of pretreating wood is to treat the wood with an embrittlement obtained by acetalizing the wood, seal it with a liquid-proof sheet, and immerse it in a liquid pressure medium to apply it. It may comprise a step of causing a large number of fine cracks in the wood structure by pressing.

A method for producing modified wood according to claim 3 is
It comprises the steps of impregnating and curing the modified treatment liquid on the treated wood that has been pretreated by the method described above.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The wood used in the present invention includes wood veneer, wood board, etc. As the wood veneer, a thickness dimension 0 cut by a slicer, a rotary race, a half rotary race, etc. It can be about 0.2 to 5 mm. Further, as the wood plate, a plate-shaped body having a thickness of about 2 mm to 10 mm obtained by cutting wood with a saw can be mentioned. Furthermore, as other wood, for example, laminated wood thin plates,
Examples include LVL thin plates, artificial veneer boards, and veneer-like decorative veneers.

Examples of the acetalization treatment of wood include glyoxalization and formalization.

The above-mentioned glyoxal conversion is carried out by applying an aqueous glyoxal solution to wood, impregnating it with a method such as forced injection (pressure reduction method, pressure method, pressure reduction pressure method, etc.) and then heating it to react it with the wood component. Done. It is preferable to use an aqueous solution of glyoxal having a concentration of 1 to 30% by weight. If it is less than 1% by weight, the effect of imparting brittleness to the veneer is small, and the effect of pressure treatment with a press or the like is also small. If it exceeds 30% by weight, the effect of imparting brittleness to the veneer is too large, This is because the veneer is severely broken by the pressure treatment with a press or the like. Heating can be done with an existing dryer or hot press, which can heat wood to a temperature of 4
It is preferable to heat to 0 ° C. to 150 ° C. for reaction. This is because if the temperature is lower than 40 ° C, the brittleness imparting effect may not be sufficient, and if the temperature exceeds 150 ° C, the veneer discolors.

Formalization includes liquid phase method and gas phase method. In the case of liquid phase method, wood is impregnated with an aqueous formaldehyde solution (concentration: 1 to 50% by weight) and then heated to react with wood components. Done by. The heating method is
The description is omitted because it is similar to the above-described glyoxalization. On the other hand, the formalization by the gas phase method is performed by injecting and sealing formaldehyde that has been heated and vaporized into a closed container into which wood is put. Formaldehyde having a concentration of 1% by weight to 30% by weight is used at a temperature of 40 ° C to 120 ° C.
This is because if the concentration is less than 1% by weight, the brittleness imparting effect on the veneer is small and the pressure treatment effect by a press or the like is small.
If it exceeds 30% by weight, the effect of imparting brittleness to the veneer is too large and the veneer is broken by the pressure treatment with a press or the like. Also, if the temperature is lower than 40 ° C, the brittleness imparting effect is not sufficient, and if the temperature exceeds 120 ° C, the veneer discolors.

The impregnation of wood with the acetalization treatment liquid and the reaction conditions with the wood component can be selected depending on the thickness of the wood used, the species of the wood, the viscosity of the acetalization treatment liquid, the concentration, and the like.

Regarding the degree of acetalization, the weight increase rate of the wood after the acetalization treatment is about 1 to 30% for glyoxal and 1 to 30 for the formalization as compared with untreated wood.
About 30% is preferable. If both are less than 1%, the effect of imparting brittleness to the veneer is small, and the effect of pressure treatment with a press or the like is also small. If it exceeds 30%, the effect of imparting brittleness to the veneer is too large. By pressurizing with a press,
This is because the veneer will break.

The treated wood subjected to the acetalization treatment has less flexibility than the untreated wood and is hard to be deformed by pressure and becomes brittle. For this reason, fine cracks due to cracks or compression buckling are likely to occur in the texture of the treated wood due to pressure.

The pressure treatment of this acetalized wood is
In order to facilitate the impregnation of the modified treatment liquid described later, it is a treatment that causes a number of fine cracks due to cracks and the like to uniformly occur in the texture of the treated wood. For example, flat plate press, roll press, hydraulic pressurization. Etc.

In the case of applying hydraulic pressure, the treated wood treated with acetal is sealed with a liquid-proof sheet and immersed in a liquid pressure medium (water, polyethylene glycol, etc.) in a pressure-resistant container, and the liquid pressure is applied. By pressurizing the treated wood with the medium, many fine cracks can be generated in the wood structure. In this case, since the treated wood can be uniformly pressed as described above, there is an advantage that a desired number of fine cracks can be uniformly generated in the treated wood.

The pressure applied to the treated wood varies depending on the pressing means, the tree species of the wood to be pressed, etc. and is not particularly limited. 300 kg / cm ² is preferred. Pressure is 5Kg / cm ²
This is because if it is less than 300 kg / cm ² , many fine cracks cannot be generated, and if it exceeds 300 Kg / cm ² , cracks in the wood structure become significantly large, which causes damage to the wood that is difficult to repair.

When a large number of fine cracks are generated in the wood structure by the above-mentioned pressing, the degree of compression is preferably less than 40% of the original thickness of the wood. Four
This is because if it exceeds 0%, the damage to the wood is significant.

The modifying treatment liquid for impregnating the pressure-treated wood structure is preferably a synthetic resin liquid capable of re-adhering the treated wood with fine cracks. Further, an antiseptic agent, a fireproof agent, or the like may be used, or a modification treatment liquid obtained by mixing these with a synthetic resin liquid may be used.

As the synthetic resin liquid, an unsaturated polyester resin liquid, an acrylic resin liquid, a styrene resin liquid, a vinyl resin liquid or the like can be used. Instead of the synthetic resin liquid, a dry oil type hardening liquid such as linseed oil is used. May be used.

Further, the impregnation of wood with such a modification treatment liquid can be carried out not only by a forced injection method such as a depressurizing method, a pressurizing method, a depressurizing and pressurizing method, but also by a coating method or a simple dipping method. . In particular, when a coating method or a simple dipping method is used as the method for impregnating the synthetic resin liquid, the wood material is impregnated with the synthetic resin liquid by hot pressing with a hot press after the coating or dipping. Since the synthetic resin liquid is accelerated and the synthetic resin liquid is cured at the same time, there is an advantage that the productivity can be further increased and the wood can be uniformly impregnated with the synthetic resin liquid.

[0024]

【Example】

Example 1 A room temperature treatment liquid prepared by adding 0.3% by weight of paratoluenesulfonic acid as a catalyst to an aqueous solution of glyoxal having a concentration of 15% by weight, and having a thickness of 2.5 mm, a width of 150 mm and a length of 4
After immersing a 00 mm hemlock veneer single plate for 5 minutes, the temperature is set to 8
It was dried with a dryer at 0 ° C. for 4 hours, and the dryer was further heated and heated at a temperature of 120 ° C. for 4 hours to obtain an acetalized veneer. The weight increase rate of the acetalized veneer thus obtained was 3%. This acetalized veneer is pressed by a flat plate press with a pressure of 200 Kg / cm ² ,
A pressure-treated veneer was obtained.

The pressure-treated veneer thus obtained was compressed to a thickness of 1.8 mm, and when observed with a scanning electron microscope, many cracks due to buckling, cracks, etc. were formed, and the synthetic resin liquid was significantly impregnated. I found that it was in an easy state.

Next, this pressure-treated veneer is dipped in an unsaturated polyester resin liquid containing a curing agent and having a viscosity of 700 cps and a temperature of 20 ° C. for 5 minutes, taken out, and the front and back surfaces are covered with a Teflon sheet. At a temperature of 130 ° C and a pressure of 10 kg / cm ²
By heating and pressurizing for 15 minutes with the hot press of 1., modified wood composed of wood and synthetic resin was obtained.

The weight gain of the obtained modified wood by impregnation with the unsaturated polyester resin is 161% of the total dry weight of the wood.
Met. This modified wood has a beautiful appearance with no unevenness of impregnation with the synthetic resin liquid, and when the cross section in the thickness direction was observed with a scanning electron microscope, the synthetic resin was found in the cell lumen of the wood. It was almost evenly packed.

(Comparative Example 1) From the same single plate as in Example 1,
A pressed veneer was obtained under the same conditions as in Example 1, except that the acetalization treatment was not performed. The obtained pressure veneer was compressed to a thickness of 2.3 mm, and when observed with a scanning electron microscope, the generation of minute cracks due to buckling or cracks in the wood cell wall was uneven.

Next, this pressurized single plate was immersed in an unsaturated polyester resin liquid under the same conditions as in Example 1 to impregnate it, and
The modified wood was obtained by applying heat and pressure with a hot press.
The weight increase rate by impregnation of the modified wood with the unsaturated polyester resin was 119%. This modified wood does not have a good appearance due to uneven impregnation of the synthetic resin liquid, and the cross-section in the thickness direction was observed with a scanning electron microscope. It was found that there was variation in the impregnation of the synthetic resin.

From the above results, Example 1 is comparative example 1
It was found to have better impregnating properties.

Example 2 Paratoluenesulfonic acid as a catalyst was added to a glyoxal aqueous solution having a concentration of 20% by weight in an amount of 0.
After dipping 5 cm thick 4 cm thick, 4 cm wide, 20 cm long Betuga in a treatment liquid containing 3% by weight (pouring rate 10
0%), dried in a dryer at 80 ° C for 3 days, and
The dryer was heated and heated at a temperature of 120 ° C. for 4 hours to obtain acetalized wood. Here, the injection rate indicates the impregnated amount of the treatment liquid with respect to the total dry weight of wood. Then, the acetalized wood is pressured to 20
It was pressed with a flat plate press of 0 kg / cm ² and compressed until the thickness and width dimensions were each about 3 cm.

The obtained pressure-treated material had a thickness dimension and a width dimension of 32 mm, respectively, and when observed with a scanning electron microscope, many fine cracks due to buckling or cracks were observed in the wood cell wall. It was happening.

Next, an epoxy resin was coated on the mouth end portion (the surface perpendicular to the length) of this pressure-treated acetalization-treated material to seal it, and it was dipped in a black dye aqueous solution at a temperature of 40 ° C. for 3 hours. The injection rate of the black dye aqueous solution after dipping was 98%, and when a section of 10 cm in length was cut from one end surface and the cross section was observed, the penetration of the dye from the four side surfaces was approximately uniform up to about 5 mm each. Had been dyed.

(Comparative Example 2) The same thickness as in Example 2 was applied under the same conditions as in Example 2 except that the same gating material was not subjected to acetalization treatment by injecting an aqueous glyoxal solution and heating. Compressed to a size of about 3 cm.

The pressure-treated wood obtained had a thickness dimension of 33.
When it was compressed to mm and observed with a scanning electron microscope, the occurrence of buckling and cracks in the wood cell wall was uneven.

Then, the mouth end portion (the surface perpendicular to the length) of this pressure-treated wood was sealed in the same manner as in Example 2 and immersed in a black dye aqueous solution under the same conditions as in Example 2. The injection rate of the black dye aqueous solution after the immersion is 36%, and the length from the one end surface is 10%.
When the section of cm was cut and the cross section was observed, it was found that the dyeing solution penetrated within 3 mm from the four side surfaces, and the 1-3 mm part where the dyeing solution penetrated was dyed. It was uneven.

From the above results, it was found that Example 2 was easier to impregnate the modified liquid and the like from the outer peripheral surface of wood than Comparative Example 1.

Example 3 The acetalized veneer obtained in Example 1 was wrapped in a watertight state with a liquid-proof sheet consisting of a 0.02 mm thick household wrap sheet, put in a pressure resistant container, Water, which is a pressurizing medium, is poured into this container, and a
Pressurized at 0 Kg / cm ² .

The resulting pressure-treated veneer has a thickness of 2.
When compressed to 3 mm and observed with a scanning electron microscope, many buckles, cracks and the like were generated in the wood structure, and the synthetic resin liquid was easily impregnated.

Next, this pressure-treated veneer was dipped in an unsaturated polyester resin liquid containing a curing agent and having a viscosity of 700 cps for 5 minutes, taken out and covered with a Teflon sheet to cover the front and back surfaces, and this was heated at a temperature of 130 ° C. , Was heated and pressed for 15 minutes with a hot press having a pressure of 10 kg / cm ² to obtain modified wood composed of wood and synthetic resin.

The weight gain of the modified wood obtained by impregnation with the unsaturated polyester resin was 165%. This modified wood has a beautiful appearance that is well impregnated with a synthetic resin solution, and the cross-section in the thickness direction was observed with a scanning electron microscope. Were almost uniformly packed.

[0042]

According to the first aspect of the present invention, by treating the wood with an acetal, it is possible to obtain brittle treated wood with reduced flexibility. Then, by pressurizing the treated wood to cause many fine cracks in the texture of the treated wood, the modified treatment liquid is uniformly impregnated in a sufficiently short time. According to claim 2, like the invention of claim 1, by subjecting the wood to an acetalization treatment, the flexibility of the wood is reduced and weakened, and further, under the condition that the liquid pressure medium does not come into direct contact with the wood. By pressurizing the wood and causing a large number of fine cracks in the wood structure, the modification treatment liquid is more easily impregnated. In particular, when the liquid pressure medium is pressed, the wood is uniformly pressed from the entire surface and is less affected by uneven thickness of the wood, as compared with pressing by a flat plate press or a roll press. Therefore, a large number of fine cracks can be generated in the wood structure, and the modification treatment liquid is sufficiently and uniformly impregnated. According to claim 3, the pretreatment of claim 1 or 2 makes it easier for the reforming treatment liquid to permeate, so that the treated wood should be sufficiently and uniformly impregnated with the synthetic resin liquid or the like in a short time. As a result, a desired modified wood composed of wood and synthetic resin can be obtained. Further, when impregnating wood with a synthetic resin liquid, not only the forced injection method, but also a simple method such as a dipping method or a coating method,
Since the synthetic resin liquid can be sufficiently impregnated into the wood, the productivity is improved. Further, as described above, by impregnating the modifying treatment liquid sufficiently and uniformly, it is possible to obtain modified wood having various properties such as good appearance, abrasion resistance, hardness and water resistance. is there.

Claims (3)

[Claims] 1. A method for pretreating wood, characterized in that brittle treated wood obtained by acetalizing wood is pressurized to cause many fine cracks in the wood structure. 2. The treated wood to which brittleness is obtained, which is obtained by acetalizing wood, is sealed with a liquid-proof sheet, and the wood is soaked in a liquid pressurizing medium to pressurize it to obtain a fine structure in the wood structure. A pretreatment method for wood, which is characterized by causing many cracks. 3. A method for producing modified wood, which comprises impregnating and hardening the modified wood liquid pretreated with the method according to claim 1 or 2.