JP2002234004A - Treatment method for dimensionally stabilizing wood - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method for dimensionally stabilizing wood capable of efficiently and economically manufacturing a wood product having high dimensional stability by suppressing the dimensional change, cracking and warpage of wood at the time of drying and making it possible to short a drying period to a large extent by thermal drying not performing humidification control. SOLUTION: Wood is dried by successively performing a process (1) for preliminarily drying wood to bring the water content of the surface layer thereof to 25-60%, a process (2) for processing the wood into a predetermined shape, a process (3) for injecting a dimension stabilizer in the surface layer of wood and a process (4) for drying the wood under heating while degassing the same without substantially performing humidification from the outside to enhance not only a yield as dried wood but also the dimensional stability of wood.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dimensional stabilization of wood, and more particularly to shrinkage, expansion and deformation of not only processed wood products but also buildings and furniture using the wood. The present invention relates to a processing method which is more efficient, can significantly reduce the processing time as compared with the conventional example, and can greatly improve the yield as a processed wood product.

[0002]

2. Description of the Related Art When wood is used as a material for building materials and furniture, the dimensional stability of a processed wood product is an important characteristic that governs the quality of a final product. In particular, it is desired to supply antiseptic, termite-prevention and drying materials which have been subjected to antiseptic / termite-prevention treatment for building materials as housing members in recent years to improve durability and dried by artificial drying or the like. This is to eliminate problems such as floor noise and doors not closing due to dimensional changes in building materials after a certain period of time has elapsed after construction.

[0003] When wood is dried from natural materials (natural drying or artificial drying), large dimensional changes and accompanying cracks and warpages occur. This is because the moisture content changes in the process of drying wood from raw wood. For example, the moisture content of raw wood differs depending on the species and location of the tree, but the sapwood of cedar immediately after cutting has a moisture content of about 160%, and most of these moistures are released during the process of drying the raw wood. Finally, the state is stabilized at an equilibrium water content of 11 to 18% (depending on the use environment and purpose). Due to the change in the water content during this time, the wood undergoes a remarkable dimensional change, which causes cracks, warpage and the like.

Therefore, when manufacturing a wood product, in order to minimize the dimensional change that occurs after the intermediate processed product, the material is sufficiently dried in the process of manufacturing the intermediate processed product from the raw material, and the dimensional change is reduced. The product is processed into an intermediate product in a state where the accompanying deformation is almost completed, and then shipped. Specifically, in the case of building materials, for example, in order to produce a product of 105 mm square, a raw material of about 110
The product is dried to about 0%, and cut out as a 105 mm square product to ensure dimensional accuracy.

[0005] Preservatives and termites may be added by infiltrating preservatives and termites. However, when a water-soluble chemical is used for such infiltration, it is necessary to re-dry it. Dimensional change occurs in the re-drying step, so that dimensional adjustment is required again.

In the artificial drying step which is performed after cutting raw wood or wood pre-dried by natural drying as square wood or plate material, an appropriate amount of water vapor is blown (sent) into the dryer (inside the can) to humidify. Meanwhile, a method of drying stepwise by controlling the difference between wet and dry bulbs in each schedule is adopted. This is because, when heating and drying is performed without adjusting the humidification, dehydration from the surface layer of the wood proceeds rapidly in the initial stage of drying, and the dehydration causes shrinkage in the surface layer to cause cracks and warpage. In general, when drying a new material of cedar, if it is heated and dried without adjusting the humidification, most of the material causes surface layer cracks and core cracks, and the yield is significantly reduced.

[0007] As a preventive measure, the material is divided into spines and dried while adjusting the humidification. However, in the case of cedar wood, even if this precaution is taken, a defect rate of 10% or more occurs.

[0008] The heat drying not only requires complicated temperature and humidity control, but also requires a long time to dry to a target moisture content, and uses a dryer that is practically used on an industrial scale. In the case of drying, for example, cedar 105 mm
It usually takes about 15 to 20 days for square timber.

In other words, this heat drying requires an opposing process of humidification for the purpose of drying, which is economically negative.

[0010]

SUMMARY OF THE INVENTION Under the above-mentioned prior art, the inventors of the present invention have conducted a dimensional change, particularly when forcedly drying (heat drying) raw materials, naturally dried materials, and antiseptic and termite-treated wood. In addition to suppressing the defect rate due to "out of order" or cracking or warping, we have been conducting intensive research to shorten the drying period.

Accordingly, an object of the present invention is to suppress dimensional changes, cracks and warpage when drying wood, to shorten the drying period by heating and drying without performing humidification control, and to achieve high dimensional stability. It is an object of the present invention to provide a dimensional stabilization method capable of efficiently and economically producing a wood product.

[0012]

Means for Solving the Problems The dimensional stabilization treatment method for wood according to the present invention, which can solve the above problems, has the gist of sequentially performing the following steps (1) to (4). are doing.

(1) Wood is pre-dried and the water content of the surface layer is adjusted to 2
5% to 60%, (2) processing into a predetermined shape,
(3) a step of injecting a dimensional stabilizer into the surface layer, and (4) a step of heating and drying while degassing substantially without external humidification.

In practicing the present invention, in the step (1), a depth of at least 8 mm from the surface layer or a depth of at least 10% from the surface with respect to the thickness of the wood is measured. By pre-drying as the surface layer, penetration of the dimensional stabilizer becomes easy,
This is preferable because the features of the present invention can be more effectively exhibited.

If the surface layer is subjected to an insizing treatment prior to the preliminary drying in the step (1), the release of water to the outside of the wood during the preliminary drying can be remarkably promoted. Not only can the required time be significantly reduced, but also the dimensional stabilizer in pre-drying (or
Injection of a preservative or termite-controlling agent (hereinafter sometimes referred to as infiltration) is preferable because it can be efficiently performed to a deep part.

At this time, it is preferable to employ pressure injection for injecting the dimensional stabilizer into the surface layer, since infiltration can be performed more efficiently. Further, the injection amount of the dimensional stabilizer is 10 kg / m ³ or more, more preferably 20 kg / m ^3.
By setting it to m ³ or more, a dimensional change in the subsequent heating and drying step can be more effectively prevented.

The type of the dimensional stabilizer used in the present invention is not particularly limited. However, the effect of the present invention, which will be described in detail later, can be effectively exerted, and when used as a building material or furniture, the harmful effect on the human body can be obtained. Without any impact on the quality of wood products
Urea, glycol compounds, sugars such as glucose, and dimensional stabilizers such as magnesium chloride, sodium chloride and barium chloride are recommended.

When the dimensional stabilizer is injected into the surface layer in the step (3), a preservative or an anti-termitic agent is also injected at the same time. Is also preferable because an excellent wood product can be obtained. In this case, the total injection amount of the water-soluble (water-diluted) working liquid (chemical solution to be injected) including the dimensional stabilizer, preservative, termite inhibitor, etc. should be 200 kg / m ³ or more based on the total amount of wood. Is desirable.

According to the present invention, dry wood having excellent dimensional stability can be obtained by adopting the above configuration. However, after the above-mentioned step (4), finish cutting for further dimensional adjustment is performed. For example, it is preferable because the dimensional accuracy of the dried wood can be further increased.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present inventors have focused on the problems of the prior art as described above, and have been working to efficiently produce a processed wood product having excellent dimensional stability with a high yield and a short processing time. In order to develop a processing method that can be used, we have been conducting research from various angles. As a result, it has been found that if the following steps (1) to (4) are sequentially performed as described above, the original object can be splendidly achieved, and the present invention has been achieved.

(1) Wood is pre-dried and the moisture content on the surface layer is adjusted to 2
5% to 60%, (2) processing into a predetermined shape,
(3) a step of injecting a dimensional stabilizer into the surface layer, and (4) a step of heating and drying while removing air substantially without external humidification.

Hereinafter, the reasons for determining the above-mentioned processing steps, preferable conditions for executing each step, preferable additional requirements, and the like will be described in detail.

In the present invention, first, preliminary drying is performed in the first step (1). This preliminary drying is a drying step performed before processing raw material or raw wood in an undried state into a predetermined shape, or after cutting into an appropriate size, and generally includes natural drying and the like. . However, in the present invention, it is extremely important to control the moisture content on the surface layer in the preliminary drying step to a range of 25 to 60%, preferably 25 to 40%.

Incidentally, this predrying step (1) is carried out in step (3).
In the pouring process, in order to efficiently infiltrate (impregnate) the required amount of dimensional stabilizer into the surface layer of the wood, pre-drying is performed to release some of the water inside the wood and create voids in the release traces It is an indispensable step, and in order to infiltrate the above dimensional stabilizer in a necessary and sufficient amount, the water content of at least the surface layer must be 60%.
% Or less, more preferably 40% or less. However, if the moisture content is excessively reduced by excessively promoting the drying in the preliminary drying step, warpage and distortion of the wood in the preliminary drying step become remarkable, which causes a reduction in the yield as a preliminary dried product. The water content in the predrying step is desirably 25% or more, more preferably about 30% or more.

Generally, water present in wood is water present in liquid form in cell cavities, intercellular spaces, and the like (hereinafter, “free water”).
) And water present in the cell wall (hereinafter, referred to as “bound water”). Free water generally refers to water having a water content of 30% or more, and bound water corresponds to water having a water content of 30% or less. The inside of the cell membrane is completely saturated with moisture,
The state in which liquid moisture does not exist in voids such as cell cavities and intercellular spaces is the fiber saturation point (FSP).
And its moisture content is 25-30 throughout all wood
% (About 28% on average).

It is generally believed that the shrinkage of wood in the drying step is caused by a decrease in water in a moisture content range below the fiber saturation point, thereby reducing the thickness of the cell wall and reducing the overall size. However, in actual drying, in addition to this shrinkage, the amount of shrinkage often abnormally increases due to deformation or crushing (falling) of cells.

When raw wood, total dry wood or wood having an arbitrary moisture content is allowed to stand in the air at a certain temperature and humidity, the wood is turned on until the water vapor pressure in the air becomes equal to the water vapor pressure based on the moisture in the wood. The absorption and release are repeated, and an equilibrium state is reached according to the temperature and humidity of the atmosphere. The moisture content at this time was determined by the equilibrium moisture content at that temperature and relative humidity.
re content). This is approximately the same for all tree species, and varies slightly depending on the usage environment and purpose.
It is said to be about%. The wood is then stabilized over a long period of time at the equilibrium moisture content.

Therefore, in the ordinary wood drying treatment, the drying is advanced in the predrying step until the water content becomes equal to or less than the equilibrium moisture content.
By performing the processing after the deformation such as the warpage of the wood due to the drying is substantially completed, the subsequent deformation of the processed product is prevented. During this time, the wood undergoes considerable shrinkage and deformation by drying until it reaches an equilibrium moisture content.Therefore, the deformed part must be cut by adjusting the dimensions during the subsequent intermediate processing, and the yield as an intermediate processed product It is a fact that it considerably decreases.

On the other hand, in the present invention, the water content of the surface layer of the wood is reduced to 25%, more preferably to about 30%, which is the fiber saturation point, in the predrying step as described above. The deformation is suppressed to a minimum, and the deformation due to the drying is suppressed to improve the yield as an intermediate product. The voids necessary for the infiltration of the dimension adjusting agent and the like performed after the preliminary drying treatment are secured by the release traces generated by the release of extracellular water, so that there is no danger of insufficient infiltration.

However, if the water content after predrying exceeds 60%, the voids at the traces of release caused by the release of moisture tend to be insufficient, and the infiltration becomes insufficient, so that the object of the present invention cannot be achieved. Is 60% or less, more preferably 4%
It is necessary to make it about 0% or less.

Thus, in the predrying step performed in the first step (1) of the present invention, by setting the water content in the range of 25 to 60%, more preferably 25 to 40%, it is possible to reduce the dimensional change in the predrying step. It is possible to sufficiently generate voids necessary for the subsequent infiltration of the dimension adjusting agent, while suppressing a reduction in yield as much as possible.

In this pretreatment step, it is desirable to adjust the water content in the entire thickness direction of the wood to the above range. However, in general, cracks caused by dimensional change due to evaporation of water are at least 8 mm or more, preferably 10 mm or more, more preferably 15 mm or more from the surface in the case of a large diameter material.
As described above, in the case of a thin sheet material, if the moisture content is controlled to 10% or more, more preferably 15% or more of the total sheet thickness in the above-described moisture content range, the bulking effect of withstanding the shrinkage stress at the time of releasing the internal moisture in the surface portion of the thickness. (Effect of suppressing dimensional shrinkage) can be secured to avoid cracking, and dimensional change can be sufficiently suppressed by infiltration of the dimensional stabilizer to the depth. Therefore,
The area to secure the moisture content in the above range at the time of preliminary drying is 8 mm or more in the case of a large diameter material at a depth position from the surface layer,
It is preferably at least 10 mm, more preferably at least 15 mm, and in the case of a plate material, at least 10%, more preferably at least 15% of the total plate thickness.

Preliminary drying is usually performed by natural drying. However, artificial drying (forced drying) can be performed to shorten the time, or natural drying and artificial drying can be performed in combination. Not restricted.

In the predrying, the time required for drying the surface layer to the water content is shortened, and the subsequent infiltration of the dimensional stabilizer is carried out in a short time and efficiently. It is also very useful to apply an insizing treatment to the surface layer. The pitch of the insizing is not particularly limited, and it is difficult to dry and infiltrate the wood and target drying, such as the density of the wood depending on the tree species, or whether the surface of the wood to be treated is a core or a sapwood. It may be appropriately determined each time in consideration of time and the like.

The depth of the insizing is not particularly limited. However, in the present invention, since the drying or the infiltration of the surface layer of 8 mm or more is effective as described above, the depth is desirably about 8 mm or more. However, even if the insizing depth is limited to about 5 to 7 mm, drying and infiltration can be greatly promoted as compared with the case without insizing.

In the case where the wood to be treated is a relatively thin plate material or is made of only sapwood, drying and infiltration of a dimensional stabilizer can be performed efficiently without insizing treatment. It is desirable to perform insizing treatment on the exposed portion of the material to promote drying and infiltration.

The pre-dried material that has been thus pre-dried is
Next, in step (2), processing into a predetermined shape is performed. In the case of the base material, in the case of the base material, cutting processing to adjust the size and shape, or further, joint processing such as ants and cams using chisels and pre-cut machines, etc., groove processing, decorative engraving,
The processing includes dowel processing, pilot hole processing of metal fittings, and the like.

The processed product thus processed is subjected to the following step (3)
The injection (infiltration) of the dimension stabilizer into the surface layer portion is performed. In this step, the surface layer is preliminarily dried to a predetermined moisture content in the step (1) or a large number of pores are formed in the surface layer by insizing treatment. When pressure injection is performed, the dimensional stabilizer is promptly infiltrated into the voids at the traces of moisture removed in the preliminary drying step. In the processed wood product into which the dimensional stabilizer has been injected, the voids on the surface layer from which moisture has escaped are filled with the dimensional stabilizer, so that the dimensional change also occurs during drying performed in the next step (4). Drying can be performed quickly and in a short time without causing the drying.

The specific conditions for injecting the chemical into the wood are not particularly limited, and ordinary conditions employed when injecting a preservative or the like may be applied. For example, immersion treatment, hot / cold bath treatment, reduced pressure injection Processing, pressurized injection processing, or the like may be employed. However, to inject drugs in a short time and efficiently,
It is desirable to employ a pressure injection process. In the pressure injection treatment, the pressure condition is not particularly limited. However, in order to complete infiltration at a depth of at least about 8 mm from the surface layer or about 10% of the total sheet thickness in a short time, the pressure is set to 4 kgf / c.
It is desirable to increase the pressure to at least m ² , more preferably at least about 15 kgf / cm ² .

The amount of the injected dimensional stabilizer is preferably at least 10 kg / m ³ , more preferably about 20 kg / m ³ , in order to enhance the dimensional stability in the subsequent drying step or practical use as a final product. It is desirable to make the above.

The type of the dimensional stabilizer used herein is not particularly limited, and various known stabilizers, for example, alkylene glycols such as ethylene glycol, propylene glycol and butylene glycol; polyethylene glycol, polypropylene glycol, and poly (ethylene glycol) Polyalkylene glycols such as butylene glycol; glycerin;
Polyoxyethylene alkyl ethers such as 1,3-butanediol, polyoxyethylene tridecyl ether and polyoxyethylene nonylphenyl ether; polyvinyl alcohol; polyvinyl pyrrolidone; vinyl acetate; polyoxyethylene sorbitan monostearate;
Saccharides such as sorbitan monooleate and D-glucose; urea compounds such as urea and methylol urea; phenolic resins; inorganic salts such as calcium chloride, magnesium chloride and barium chloride; Can be appropriately used in combination, but the present invention is not limited thereto. Glycol compounds and urea are more common in consideration of dimensional stabilization performance, safety when practically used as houses and furniture, and the like.

It is preferable to inject a preservative, an anti-termitic agent, etc. at the same time as injecting the above-mentioned dimensional stabilizing agent, since it is possible to perform preservative treatment, termite-inhibiting treatment, etc. simultaneously with dimensional stabilization. The preferable injection amount when simultaneously injecting these preservatives and termites is water-soluble (diluted with water) including dimensional stabilizers, preservatives, termites, etc. in order to effectively utilize the action of the injected drugs. It is desirable that the total injection amount of the working liquid (chemical liquid for infiltration treatment) be 200 kg / m ³ or more based on the total amount of wood.

The preservatives and termites are not particularly limited, and all known agents can be used. Representative preservatives are higher organic quaternary ammonium compounds and aromatic benzimidazole derivatives. (4-Thiazolyl) -1H-benzimidazole, 2- (4-thiocyanomethylthio) -benzothiazole, 8-hydroxyquinoline copper which is an aromatic quinoline derivative,
1- [2- (2 ', 4'-dichlorophenyl) -4-propyl-1,3-dioxolan-2-yl-methyl] -1H-1,2,4-triazole, which is an aromatic triazole derivative [2- (2 ', 4'-dichlorophenyl-1,3-dioxolan-2-yl) methyl] -1H-1,2,4-triazole, α- (2,4-chlorophenylethyl) -α- (1, 1-
(Dimethylethyl) -1H-1,2,4-triazole-1-ethanol, α- (4-chlorophenyl) -d- (1-cyclopropylethyl) -1H-1,2,4-triazole-1-ethanol, Examples thereof include copper compounds such as cupric oxide, but are not limited thereto.

Typical termiticides include carbamate compounds such as fenobcarb and carbaryl, and pyrethroid compounds such as tralomethrin and permethrin.
Bifenthrin, etc., etofenprox, silafluofen, imidacloprid, acetamiprid,
Examples thereof include boric acid and higher quaternary ammonium salts, but are not limited thereto.

In the present invention, in addition to the above preservatives and termites, it is possible to simultaneously inject, for example, a fire and flame retardant if necessary.

After the pouring, final drying is performed in step (4). The drying step employed in the present invention is a conventional method of "drying while appropriately humidifying from the outside" in that "heating and drying while evacuating without substantially performing humidification from the outside". Are significantly different.

That is, in the conventional forced drying step, a method is employed in which an appropriate amount of water vapor is blown into a dryer to perform stepwise drying while humidifying. This is because, as described above, when heating and drying without humidification adjustment, dehydration from the surface layer of wood progresses rapidly in the early stage of drying, the surface side shrinks, and the core side is dried This is because cracks, warpage, and the like are caused on the surface layer side. Therefore, it took a long time to reach the target moisture content.

However, in the present invention, the above steps (1) to (3)
As described above, a predetermined amount of moisture in the surface layer that causes warpage and deformation during drying is volatilized and removed as described above, and the voids are filled with a predetermined amount of a dimensional stabilizer. The volatilization and removal of water on the core side can be promoted without shrinkage. That is, in the forced drying step, even if the inside of the dryer is heated without adjusting the humidification and the heating and drying is performed while removing the water vapor released from the core part, the core part is not shrunk on the surface layer side. Since the drying can proceed, the time required for drying can be significantly reduced.

By the way, in the conventional method in which heating and drying are performed while adjusting the humidification, when a dryer having a level of 30 m ³ is used, a drying time of about 300 hours (13 days) is usually required for a cedar core holding material, and wood is required. In order to proceed with drying without causing a rampage, the temperature and humidity in the dryer must be strictly controlled according to the progress of drying. Also,
In the case of cedar wood, it has a lumber characteristic of a core holding material, so it is necessary to perform a spine splitting process for the purpose of preventing cracking. However, in the present invention, since there is no need to worry about drying and shrinkage of the surface layer during drying and the accompanying warpage and deformation as described above, heating without humidification and suction of generated steam out of the dryer are performed. You just need to vent.

For this reason, the time required for drying varies depending on the species of the tree when using a dryer of the same level as described above, but the drying can be completed in about 5 to 8 days, and the time required for drying is greatly reduced. It is possible to do. Moreover, in the present invention, the complicated and strict temperature at the time of drying as in the prior art is used.
Humidity control is not required at all, and heating is performed while air is simply removed, so that the drying operation is extremely simplified. At the same time, since the shrinkage-suppressing effect of the dimensional stabilizing agent prevents cracks and the like in the surface layer of the wood and the like, spinning for the purpose of preventing cracks becomes unnecessary.

The drying temperature varies depending on the type of tree and cannot be determined uniformly. However, in order to carry out the drying in a shorter time without causing a change in the material of the wood or the accompanying discoloration, a temperature of less than 95 ° C. More preferably 85
It is desirable to adopt a temperature of 70 ° C. or lower, more preferably 80 ° C. or higher.

Further, in the present invention, most of the water causing the dimensional change is removed in advance in the predrying step (1), and thereafter, the gap in the surface layer portion is filled with the dimensional adjusting agent by injecting the dimensional adjusting agent. Since it has been buried, there is almost no dimensional change even after assembling as a final product, as well as the drying process of (4), which has high dimensional accuracy and causes deformation and distortion after assembly. No building materials or woodworking products can be obtained.

As described above, according to the present invention, by sequentially performing the steps (1) to (4), the dimensional accuracy is high and deformation and distortion after assembly can be suppressed as much as possible. Depending on the level of dimensional accuracy required for the product, it is of course effective to apply further finishing grinding etc. after the above step (4) and use it as a material for fine woodwork products with higher dimensional accuracy. is there.

There is no particular limitation on the type of wood used in the present invention. All kinds of broad-leaved trees such as chestnut, zelkova, beech, maple, oak and the like can be used, but the features of the present invention are particularly effective for baizuga, hinoki, cedar, beehiba, and hiba.

[0055]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to experimental examples. However, the present invention is not limited to the following experimental examples, and the present invention is not limited thereto. Modifications may be made and all of them are included in the technical scope of the present invention.

EXPERIMENTAL EXAMPLE 1 In the dimensional stabilization treatment method of the present invention, penetration (infiltration) of a drug is indispensable in order to exert its effect effectively. Therefore, a permeation confirmation test for each material moisture content was carried out on Bleedingwood (hemlock), which is generally distributed as a housing member. The moisture content was measured by using a Wakaru type moisture content measuring device (handy type) to measure the moisture content of the surface layer (from the surface to a depth of about 10 mm) of the test material. 60%, 61-80%, 81
１００100%. The dimensions of the wood used were 105
mm × 105 mm × 3,000 mm.

The reagent used was 4.0% (W) of "Mitrek ACQ" (copper / alkylammonium compound-based wood preservative manufactured by Koshiip Reserving Co., Ltd .: JIS K 1570 standard) as a preservative / anticidal agent. / W) Using an aqueous solution, as a dimension stabilizer, 4.7% (W / W) of polyoxyethylene tridecyl ether (hereinafter referred to as PO), 5.3 of urea
% (W / W) of the admixture was used.

The pressurized injection is performed in accordance with JIS A 9002, and the schedule at that time is 30 minutes before exhaust (600 mmHg).
Above), pressurization 120 minutes (15.2 kgf / cm ² ), and post-exhaust 30 minutes (600 mmHg or more).
The injection amount was calculated by the following equation (I).

Further, in order to confirm the effect of dimensional stabilization, a temperature of 8
Artificial drying was performed for 5 days under a forced evacuation condition without humidity control at 0 ° C., and the dimensional shrinkage of the test material was measured. The results are shown in FIG. Injection amount (kg / cm ³ ) = (weight after wood pressurized injection process-weight before wood pressurized injection process) / volume ... (I)

As is clear from FIG. 1, in the test material having a water content of the surface layer portion exceeding 60%, the permeability of the drug decreases. This is thought to be because the cells inside the wood are filled with moisture, and it is difficult to penetrate the drug even by the pressure injection treatment. Therefore, in order to provide dimensional stability by the drug effect, it is necessary to perform some kind of water content adjustment before the pressure injection treatment is performed.

Further, as a result of performing artificial drying using this test material and measuring the amount of dimensional shrinkage, as shown in Table 1 below, it was confirmed that the amount of injection of the dimensional stabilizer was greatly affected.

[0062]

[Table 1]

FIG. 2 is a graph showing the result of examining the relationship between the decrease in water content and the dimensional shrinkage due to the preliminary drying of the test wood. The test wood was preliminarily dried by leaving it outdoors (natural drying). It shows a decrease in the water content at that time and a change in the dimensional shrinkage rate accompanying the decrease. Note that the shrinkage ratio means a value calculated by the following equation.

Shrinkage = [(dimension before pre-drying-dimension after pre-drying) / dimension before pre-drying] × 100 (%) In the present invention, pre-drying is performed as described above to enable the injection of a drug. In this predrying step, dimensional shrinkage occurs as the water content decreases. As is clear from FIG. 2, the dimensional shrinkage rate until the water content reaches about 25% by predrying is relatively small, and the shrinkage rate is 1%. It remains at the 0.0% level. However, the water content after the preliminary drying is 2
When the drying is advanced until it reaches less than 5%, the shrinkage rate rises rapidly, and a large increase in the shrinkage rate is observed.

That is, from this graph, it can be seen from the graph that when the raw wood is pre-dried, if the water content in the pre-drying step of the wood is kept at a level of 25%, the dimensional change of the raw wood (and therefore the deformation of the raw wood accompanying it) ) Can be minimized, whereby the throughput can be reduced for dimensional correction, such as cutting, and the yield as a wood product can be increased.

On the other hand, FIG. 3 shows the relationship between the water content and the drug injection amount when the drug was injected (infiltrated) into the test wood preliminarily dried to a predetermined water content. The effect of suppressing dimensional shrinkage when heating and drying while deaeration without external humidification according to the step (4) (A
14 is a graph showing the result of examining the relationship of SE). Here, ASE means a value obtained by the following equation.

ASE = [(shrinkage ratio of untreated wood−shrinkage ratio of treated wood) / shrinkage ratio of untreated wood] × 100 (%) Shrinkage ratio of untreated wood = [(dimension before chemical injection−untreated material) Of dried wood) / dimension before chemical injection] × 100 (%) Shrinkage of treated wood = [(dimension before chemical injection−dimension after drying of treated wood) / dimension before chemical injection] × 100 (%)

As is apparent from FIG. 3, the lower the water content after predrying, the higher the amount of drug injected and the tendency to increase the ASE value, which clearly shows that the water content after predrying is particularly high. If the rate exceeds 60%, the insufficient amount of the drug injected due to insufficient drying becomes conspicuous, and as a result, only a low level ASE value can be obtained. However, in the case of pre-drying until the water content becomes 60% or less, more preferably 40% or less, the drug injection amount is greatly increased and a high level ASE value is obtained.

From the results shown in FIGS. 2 and 3, the amount of dimensional change in the predrying step is kept to a minimum, and a sufficient amount of drug is secured to secure a high ASE value after drying. It is understood that the moisture content at the time of preliminary drying should be adjusted to a range of 25 to 60%, more preferably 25 to 40%.

FIGS. 4 (A) to 4 (C) show test materials obtained by injecting the drug into the pre-dried materials having the water content of 27%, 39% and 72% before the injection of the drug obtained in the above experiment. The test material was cut at the center portion (1,500 mm from the mouth) to show the state of drug infiltration from the surface layer of the wood.

As is clear from these figures, FIG.
In (A) and (B), a uniform drug infiltration layer is observed on the wood surface layer. However, in FIG. 4 (C), since the water content before injection exceeds 60%, there is a shortage of the drug infiltration. It is confirmed.

Therefore, in order to secure a sufficient amount of the drug to be injected from the viewpoint of stabilizing the dimensions using the drug, the water content before the injection of the drug should be about 60% or less, more preferably about 40% or less. It can be seen that the purpose of dimensional stabilization can be effectively exhibited thereby.

Experimental Example 2 In Experimental Example 1, it was confirmed that adjusting the water content of the surface layer portion to 40% or less was a major point for effectively exerting the present invention. Therefore, in this experimental example,
Hemlock material was used as test wood, insizing treatment was performed before pressure injection treatment, and then natural drying (leaving outdoors) was performed to check the change in moisture content of the material.

As the test material, as in the case of the first experimental example, 100 pieces of Batesga material, which is a general distribution material, were used. The water content was measured at three places in the fiber direction before the insizing treatment, and the same place was measured over time. The insizing treatment at that time is 4,500 pieces / m ² , about 10 mm from the surface.
The condition for leaving was about 500
A 25 mm-thick slat was installed at three places, a mm part and a central part, and left standing outdoors with air permeability. FIG. 5 shows the results.

As is clear from FIG. 5, the moisture content of the surface layer of the wood decreased to about 40% in the test material subjected to the insizing treatment about two weeks after the outdoor exposure. From this result, it can be seen that when the insizing treatment is performed, the drying speed can be increased to about three times as compared with the case without the insizing, and the drying can be efficiently performed at low cost.

In addition, this test material was used for the experiment 1
In the same manner as described above, when the pressure injection treatment of the drug was performed in accordance with JIS A 9002, the average injection amount of all the drug solutions was 245.6 kg / m.
³ can be secured, the injection amount of the dimensional stabilizer, 11.5kKg / m ³ as PO, 13.0k / m ³ as urea
Was confirmed, and a sufficient dimension stabilizing effect could be obtained even in the subsequent drying treatment.

Experimental Example 3 In Experimental Example 1, it was confirmed that shrinkage, which is an inherent property of wood, can be suppressed by pressurizing injection of a dimensional stabilizing agent. Next, an artificial drying test was conducted to improve the drying speed. Was done. In addition, as a test tree species, a cedar core material (without spine splitting), which is most difficult to dry in terms of dry cracking, was used, and a comparative experiment was performed between the case where the present invention was applied and the conventional drying method.

In the conventional method, when wood is artificially dried as described above, humidification management is performed to minimize dry cracking, shrinkage, twisting, warping, etc. of the surface layer of the wood, and a stepwise schedule is set. Drying. A specific example of a drying schedule according to the conventional method is shown in Table 2, and a drying condition called medium-temperature drying (range of about 60 to 90 ° C.) is set. Therefore, in this experimental example, the schedule in Table 2 was adopted as a conventional method, and in the present invention example, artificial drying was performed under the conditions shown in Table 3 on a schedule without humidification control.

As the dimensional stabilizing agent, polyoxyethylene tridecyl ether (PO) 4.7% (W /
W) with 5.3% (W / W) of urea and 4.7% (W / W) of 1,3-butanediol (hereinafter referred to as BG)
Two formulations of a mixture of urea and 5.3% (w / w) urea were used. The pressure injection treatment was performed in accordance with JIS A 9002, as in Experimental Examples 1 and 2.

The artificial drying was performed for 8 days under the conditions of Table 2 in the conventional method and the conditions of Table 3 in the present invention after the pressure injection treatment. In the moisture content measurement, an estimated total dry weight is calculated in advance,
The water content was calculated from the estimated total dry weight by performing weight measurement at appropriate intervals for each elapsed time.

[0081]

[Table 2]

[0082]

[Table 3]

FIG. 6 shows the change over time in the water content when the conventional method and the method of the present invention are adopted. This figure shows a case where PO and BO (butylene glycol) are used as the dimension stabilizer. As can be seen from this figure, by employing the method of the present invention, drying can be performed extremely efficiently. In the present invention, the moisture content is reduced to 20% by drying for 8 days.
While the water content is reduced to below, the water content is reduced only to about 40% in the conventional method.

This is because, in the method of the present invention, efficient drying is performed from the beginning of drying, whereas in the conventional method, in order to prevent cracking and warping of wood, a process of increasing temperature → steaming → drying is adopted. This is because the drying speed must be significantly delayed, and the final moisture content level cannot be sufficiently reduced by humidification. That is, according to the present invention, it can be seen that drying can be efficiently performed in a short time.

[0085]

The present invention is constituted as described above. When drying wood, the moisture content of the surface layer at the time of preliminary drying is specified, and the infiltration of the dimensional stabilizer after processing and the subsequent By combining heating and drying without humidification, cracks, warpage, distortion, etc. due to dimensional changes in the raw wood during drying are suppressed as much as possible, and the yield as a processed product is increased, and subsequent dimensional changes are also suppressed. A high-precision wood product can be obtained, and if this method is employed, the time required for drying can be greatly reduced as compared with the conventional drying method.

The dried wood obtained by drying according to the present invention has excellent dimensional accuracy as described above and a small dimensional change thereafter, but depending on the needs of the user, after the above-mentioned step (4), furthermore, By adjusting the final dimensions such as finish grinding, it is also possible to obtain high quality wood with even higher dimensional accuracy.

[Brief description of the drawings]

FIG. 1 is a graph showing the effect of the moisture content of wood after predrying on the amount of injected chemical.

FIG. 2 is a graph showing the relationship between the moisture content after preliminary drying of test wood and dimensional shrinkage.

FIG. 3 is a graph showing the relationship between the water content after predrying and the amount of injected chemical, and the relationship between the dimensional shrinkage suppression effect (ASE) during subsequent drying.

FIG. 4 is an explanatory sectional view showing an impregnated state after impregnation of a drug obtained in an experimental example.

FIG. 5 is a graph showing the effect of the presence or absence of the insizing process on the transition of the water content in comparison.

FIG. 6 is a graph showing a change in moisture content when the method of the present invention and the conventional method are adopted.

[Explanation of symbols]

 1 Part impregnated with drug 2 Part not impregnated with drug

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 2B230 AA01 AA05 AA15 AA16 BA03 BA04 BA18 CB01 CB06 CB12 CC30 EB01 EB05 EB12 EB13 EB26 2B250 AA01 AA13 BA03 BA05 BA08 CA11 FA21 FA25 FA47 GA03 HA01

Claims (9)

[Claims] 1. A method for stabilizing the dimensions of wood, comprising sequentially performing the following steps (1) to (4). (1) a step of pre-drying the wood to make the water content of the surface layer part 25 to 60%; (2) a step of processing into a predetermined shape; (3) a step of injecting a dimensional stabilizer into the surface layer part; ) Thereafter, a step of heating and drying while degassing substantially without external humidification. 2. The processing method according to claim 1, wherein in the step (1), a surface layer portion of at least 8 mm or more from the surface layer is preliminarily dried. 3. The processing method according to claim 1, wherein in step (1), at least 10% or more of the surface layer portion from the surface layer with respect to the thickness of the wood is pre-dried. 4. The processing method according to claim 1, wherein an insizing treatment is performed on the surface layer prior to the preliminary drying treatment in the step (1). 5. The injection amount of the dimensional stabilizer is 10 kg / m ^3.
The processing method according to claim 1, wherein: 6. The processing method according to claim 1, wherein the injection in the step (3) is pressure injection. 7. The treatment method according to claim 1, wherein a urea and / or a glycol compound is used as the dimension stabilizer. 8. The method according to claim 1, wherein in step (3), a preservative and / or termiticide are injected together with the dimensional stabilizer. 9. The processing method according to claim 1, further comprising, after the step (4), performing a cutting process for adjusting a dimension.