JPH068212A - Method of setting shape of wood - Google Patents

Abstract

PURPOSE:To set a deformed shape of wood while keeping woody impression intrinsic to wood by a method wherein, after wood is plasticized to be deformed, the wood is heated under a state that the vapor of a formaldehyde monomer is applied thereto, whereby the formaldehyde is made to react with the wood. CONSTITUTION:When a shape of wood is set, the wood is first plasticized to be deformed. Then, the wood is heated under a state that the vapor of a formaldehyde monomer is applied thereto. By this method, the formaldehyde monomer is made a to react with the wood, thereby setting the deformed shape of the wood. In this case, the formaldehyde monomer is produced in advance with a formaldehyde derivative and an acid catalyst, and said monomer thus prepared is allowed to react with the wood. That is, after the wood is softened and deformed, crosslinking among ligneous parts in the interior of the wood is performed by formalization, thereby achieving the setting of the shape of the wood. Accordingly, while keeping woody impression intrinsic to wood, the deformed shape of the wood can be set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of deforming and fixing wood used as housing equipment, furniture, building materials, etc. into a shape suitable for use.

[0002]

2. Description of the Related Art A technique for plasticizing wood, which is a means for fixing the wood after it is bent or compressed to deform its shape and then fixed, is divided into plasticizing, deforming and fixing steps. In other words, it is a method of following each step of plasticizing, that is, softening, and then bending or compressing the wood to deform it and fixing it in that shape.

As a method of softening wood, the following methods can be mentioned. (a) Boiling, steam heating method This is a method of placing wood in boiling water or steam, and because hemicellulose or lignin, which is a constituent of wood, is thermally softened, the wood becomes soft and can be greatly deformed. Become.

(B) Microwave heating method This is a method of irradiating microwaves with water contained in the wood. Since the whole wood can be heated in a short time, it has the effect of shortening the treatment time. is there. In any of the above methods, the shape can be fixed by drying the softened wood while the softened wood is bent or compressed and deformed. However, there is a problem that the deformed shape fixed by these methods is recovered when the wood contains water and returns to the original shape again.

In order to solve these problems, the following methods can be mentioned as a method of fixing the shape of wood with suppressed recovery. (c) Immobilization by impregnation with phenol resin This is a method in which wood impregnated with a water-soluble phenol resin is thermally softened, and the resin is cured while being deformed to immobilize it. This immobilization is due to the bulking effect of the phenolic resin. In this method, the wood is hydrophobized, recovery after deformation is suppressed, and effective fixing is performed.
However, there is a problem in that the original characteristics of wood such as hygroscopicity and air permeability are lost due to the use of resin.

(D) Immobilization under high-pressure steam This is a method of pressurizing wood and heat-softening it under high-temperature steam. The wood is treated under conditions of 150 ° C. to 200 ° C. and 2 MPa for several minutes. Since the deformed shape is fixed,
The feature is that the deformed shape is fixed in a short time.
However, it is pointed out that wood is discolored by steam treatment at high temperature and high pressure.

[0007]

As described above, the deformation and immobilization treatment of the wood shape is carried out by various methods, but the one that achieves the suppression of the deformation recovery is combined with the resin impregnation. There is only the above method and the high temperature and high pressure steam treatment. However, in that case, the texture of the wood disappears, and
It has a defect such as discoloration of the material.

[0008] Therefore, an object of the present invention is to provide a method of fixing the deformed wood shape while maintaining the original wood texture of the wood.

[0009]

In order to solve the above problems, a method of fixing the shape of wood according to the present invention is to plasticize and deform wood, and then heat the formaldehyde monomer by heating it under formaldehyde monomer vapor. The deformed shape of the wood is fixed by reacting with. That is, after the wood is softened and deformed, the wood shape is fixed by cross-linking the wood parts inside the wood by formalization.

The raw material wood for reforming used in the present invention is not particularly limited, and examples thereof include log logs, lumber products, sliced veneer and plywood. There is no limitation on their tree species. As a method of plasticizing these raw material woods, a boiling treatment, a steam heating treatment, a microwave heating treatment, or the like is performed. The method of plasticizing or softening the wood is not particularly limited, but a treatment that does not cause discoloration of the material by the softening treatment is desirable.

The method of deforming the wood, which is carried out after the softening treatment, is not particularly limited, but usually, the softened wood is temporarily dried and dried by air drying or heat drying. At the time of drying, it is necessary to remove excess water in the wood and adjust the water content to an appropriate level. This is because when there is excess water during formalization, the formaldehyde monomer is easily polymerized by the water to form an oxymethylene chain, and in such a case the effect on shape fixing is small, and due to the action with the acid catalyst. This is because the discoloration of wood becomes large.

Next, the formalization step is carried out by a gas phase reaction. As the formaldehyde supply source, paraformaldehyde, trioxane, tetraoxane, etc. can be used, but trioxane and tetraoxane are solid, have no formalin odor, and easily sublime,
It is preferable to use trioxane or tetraoxane because it has an advantage that formaldehyde monomer is easily obtained at the time of decomposition.

As the formalization catalyst, chlorides such as hydrogen chloride, zinc chloride and iron chloride, sulfates such as iron sulfate, and boric acid and salts thereof, and acid catalysts such as sulfur dioxide are used alone or in combination. be able to. Although not particularly limited, it is preferable to use sulfur dioxide (SO ₂ ) because the strength deterioration after the treatment is small if it is used.
Further, in order to accelerate the decomposition into formaldehyde monomer, it is possible to add another catalyst to this sulfur dioxide and use two or more kinds of catalysts.

When SO ₂ is used, the SO ₂ produces formaldehyde, water to give hydromexmethyl sulfonic acid,
Since this is said to accelerate the crosslinking reaction, it is necessary to control the water content of the wood as described above. The water content of wood is adjusted to 10% or less, but 1-3
% Is preferred. Usually, if it exceeds 10%, deterioration or discoloration due to acid may occur. However, it depends on the reaction bath volume and the wood volume ratio. This water content is SO ₂
It also applies to other catalysts.

The concentration of the formaldehyde monomer is not particularly limited depending on the degree of formalization, but is 1 × 10.
^-3 to 1 × 10 ^-1 mol / dm ³ is desirable. If this concentration exceeds the above range, the partial pressure of the formaldehyde monomer may be higher than atmospheric pressure. The catalyst concentration is also not particularly limited, and in the case of SO ₂ , it is desirable to be about 1/20 to _1/2 of the formaldehyde concentration.

In the process of formalization, as usual, after impregnating the compound, the wood having the adjusted water content is put into the reaction tank. Next, an appropriate amount of formaldehyde derivative is added as a solid, and when the acid catalyst is a solid, it is added at the same time, and the temperature inside the tank is raised. The temperature is preferably 80 to 150 ° C. If the temperature exceeds this range, deterioration or discoloration of wood may occur, and if the temperature falls below this range, the reaction may not proceed sufficiently. The heating time is not particularly limited, but is preferably 8 to 24 hours. Below this range, the reaction may not be sufficient.
Next, after depressurizing the inside of the tank (preferably 100 mmHg or less), when the acid catalyst is a gas, the acid catalyst may be introduced into the reaction tank and the reaction may be performed while heating for a predetermined time. However, in order to shorten the treatment time and reduce the deterioration of the wood due to the acid catalyst, the first preferred method is to introduce the formaldehyde derivative and the acid catalyst into separate reaction vessels and decompose the formaldehyde derivative by heating. Formaldehyde monomer,
It is a method of introducing it into a reaction vessel for formalization and reacting it with wood. The second method is formalization using formaldehyde obtained by another method. According to these methods, the time required for decomposition of formaldehyde can be shortened, and further, discoloration of wood can be prevented from becoming large due to the action with the acid catalyst.

In the method of the present invention, it is also possible to apply steam after introducing steam into the wood. Pressurization can help the penetration of steam into the wood. The pressurizing method may be a method in which the compounding amounts of the formaldehyde derivative, the acid catalyst, the wood volatile component, water, etc. are adjusted in advance so that the total pressure in the tank becomes 1 atm or more. Alternatively, a method of introducing an inert gas such as nitrogen can be used. By these methods, it is possible to treat the inside of the wood, and the treatment time can be shortened.

Next, after heating for a predetermined time to react the wood with the formaldehyde monomer, the gas in the reaction tank is exhausted under reduced pressure while being heated. By sufficiently exhausting this,
Most of the unreacted gas in the wood can be removed.
The wood shape can be fixed by the above steps.

[0019]

[Function] If the softened and deformed wood is reacted with the formaldehyde monomer to fix the deformed shape, the wood texture is not lost even after the deformation and fixation, and the deformation is not recovered by moisture. Therefore, it is possible to fix the wood shape sufficiently.

[0020]

EXAMPLES Examples of the present invention will be specifically described below together with comparative examples. -Example 1-A 20x20x30 mm cedar grain is steamed with 0.5 MPa steam for 3 minutes, then compressed to 15 mm in the R direction, air-dried, and dried in a dryer at 100 ° C for several hours. It was

Next, a compression material having an adjusted water content was placed in a reaction vessel for formalization, the inside of the vessel was heated to 120 ° C., and the inside of the vessel was depressurized (50 mmHg) to carry out another reaction in advance. Formaldehyde monomer (HCHO: 1.5 × 10 ^-2 mo obtained from trioxane and SO _{2 in a} bath)
A mixed gas of 1 / dm ³ and SO ₂ : 1 × 10 ⁻³ mol / dm ³ ) was introduced into the reaction vessel, and the temperature was kept at 120 ° C. for 8 hours to fix the shape of wood.

Example 2 A cedar grain of 20 × 20 × 30 mm was steamed with steam of 0.5 MPa for 3 minutes, compressed to 15 mm in the R direction, air-dried, and then dried in a dryer at 100 ° C. for several hours. It was dried. Next, the compression material with the adjusted water content was placed in a reaction vessel for formalization, the temperature inside the vessel was raised and kept at 80 ° C., the inside of the vessel was depressurized (50 mmHg), and trioxane was previously set in another reaction vessel. formaldehyde monomer obtained from _{SO 2 (HCHO: 1.0 × 10} -2 mol / d
_{^{m 3, SO 2: 1 ×}} 10 a mixed gas of ^-3 mol / dm ³⁾ was introduced into the reaction vessel, while maintaining the temperature at 80 ° C., pressurized to about 3 atm further introducing nitrogen, 8 The wood shape was fixed by keeping the time.

Example 3 A cedar grain of 20 × 20 × 30 mm was steamed with steam of 0.5 MPa for 3 minutes, compressed to 15 mm in the R direction, air-dried, and then dried in a dryer at 100 ° C. for several hours. It was dried. Next, the treated material having the adjusted water content is put in a reaction vessel for formalization, and the temperature inside the vessel is raised and kept at 120 ° C.,
The inside of the tank was depressurized (50 mmHg), and formaldehyde monomer (HCHO: 1.0 × 10 ⁻² mol / H2O) obtained from trioxane and SO ₂ in another reaction tank in advance.
dm ³ , SO ₂ : 1 × 10 ⁻³ mol / dm ³ ) was introduced into the reaction vessel, and the temperature was kept at 80 ° C.
After holding for a period of time, nitrogen was introduced and the temperature was maintained at about 3 atm for 4 hours to fix the wood shape.

-Example 4-A 20 x 20 x 30 mm grain of cedar grain was saturated with water, and then irradiated with microwaves having a frequency of 2450 MHz to reach 9 m in the R direction.
It was compressed to m, air-dried, and dried in a dryer at 100 ° C. for several hours to immobilize the compressed material. Formalization was performed in the same manner as in Example 1 to fix the compression material.

-Example 5-A 20 × 20 × 30 mm cedar grain was saturated with water, and then irradiated with microwaves having a frequency of 2450 MHz for 9 m in the R direction.
It was compressed to m, air-dried, and dried in a dryer at 100 ° C. for several hours to obtain a compressed material. Formalization was performed in the same manner as in Example 2 to fix the compression material.

-Comparative Example 1-A cedar grain of 20 × 20 × 30 mm was steamed with steam of 0.5 MPa for 3 minutes, then compressed to 15 mm in the R direction, air-dried, and then dried at 100 ° C. in a drier. Drying was performed for an hour to obtain a compressed wood. -Comparative Example 2-A 20x20x30 mm cedar grain was impregnated with a phenol resin having a concentration of 20%, and compressed to 15 mm in the R direction while heating at 100 ° C to cure the resin to obtain a compressed wood. .

Comparative Example 3 20 × 20 × 30 m in a pressure vessel having a pressure resistance of 2.0 MPa
The cedar grain of m of m was steamed with steam of 0.5 MPa for 3 minutes, then compressed to 15 mm in the R direction, and then the steam pressure was increased to 1.6 MPa to perform immobilization treatment for 10 minutes. In the above examples, drying at 100 ° C. resulted in a water content of wood of about 3%.

For the above Examples and Comparative Examples, in order to confirm whether or not the deformation was fixed, the compressed material was boiled in hot water for 2 hours, and the case where the dimensions were completely restored was 100.
%, The recovery rate was measured as 0% when completely fixed. Further, the color difference change was also measured using a color difference meter, and the change in material color due to the treatment was evaluated by the value of Delta E.

Table 1 shows the results of each immobilization treatment.

[0030]

[Table 1]

In Comparative Example 1 in which only compression deformation was carried out, the recovery rate was as high as 90% and the shape was hardly fixed, whereas the one subjected to formalization treatment had a compression rate of 50%. It is not recovered at all, and even if the compression rate is 70%, the recovery rate is 1 to 2%, which shows that the deformed shape is almost fixed. In addition, there is almost no color change due to the processing, and it can be seen that the formalization processing fixes the shape after deformation without impairing the wood texture.

[0032]

As described above, the method for fixing the shape of the wood according to the present invention fixes the deformed shape by reacting the wood with the formaldehyde monomer after softening and deforming the wood. Even after that, the texture of the wood is not lost, the deformation due to moisture does not recover, and the wood shape can be fixed sufficiently.

[Procedure amendment]

[Submission date] September 25, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

[0013] As formal catalysts, salts of hydrogen, zinc chloride, chlorides such as iron chloride, sulfate salts such as iron sulfate, and boric acid and their salts, or together solely an acid catalyst sulfur dioxide Can be used. Although not particularly limited, if sulfur dioxide (SO ₂ ) is used, strength deterioration after treatment is small, and thus it is preferable to use it.
Further, in order to accelerate the decomposition into formaldehyde monomer, it is possible to add another catalyst to this sulfur dioxide and use two or more kinds of catalysts.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Arihiro Adachi 1048, Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd.

Claims (2)

[Claims] 1. A method for fixing the shape of wood, which comprises plasticizing and deforming wood, and then heating it under formaldehyde monomer vapor to react the formaldehyde monomer with the wood to fix the deformed shape of the wood. 2. A formaldehyde monomer is previously produced from a formaldehyde derivative and an acid catalyst,
The method for fixing the shape of wood according to claim 1, wherein the shape is made to react with wood.