JP7227584B2 - Method for producing wood with excellent moisture retention - Google Patents

Description

TECHNICAL FIELD The present invention relates to a technology for improving moisture retention of wood.

Wood has many advantages such as being light, strong and easy to process, excellent in heat insulation and soundproofing, resistant to condensation, and has a humidity control effect, and is used for various purposes such as building materials and furniture. It is However, the degree of humidity conditioning action (moisturizing property) of wood is determined by the equilibrium moisture content of wood, and the equilibrium moisture content is about 15% regardless of the type of wood. Therefore, it is not possible to control moisture retention simply by selecting the type of wood.

Patent Document 1 discloses that wood is impregnated with an N-methylol-based resin liquid and heated to react with wood (cellulose). The N-methylol-based resin liquid may contain polyethylene glycol, It is described that glycerin may be blended as a moisturizing agent and an agent for preventing deterioration of material strength. However, these polyethylene glycols and glycerin are used as additives for N-methylol-based resin liquids, and contribute little to improving the moisture-retaining property of wood itself. In addition, since the N-methylol-based resin liquid is used, the texture of the wood is spoiled.

By the way, in Patent Document 2, alkylene glycols and the like can be used as a dimensional stabilizer, and when the dimensional stabilizer is injected into the surface layer of wood pre-dried to a moisture content of 60% or less and dried by heating, the surface layer It is described that the shrinkage can be prevented. However, it is not described that alkylene glycols and the like increase the moisture retention of wood.

JP-A-5-154808 JP-A-2002-234004

The present invention has been made in view of the circumstances as described above, and its object is to establish a technique capable of improving the moisture-retaining property of wood.

The present inventors have made intensive studies to solve the above problems, and found that after injecting a predetermined chemical into wood, the chemical effectively functions as a moisturizing agent when the wood is dried without heating. , found that the moisture retention of wood can be remarkably improved, and completed the present invention.
That is, the method for producing wood according to the present invention includes an agent composed of at least one selected from polyols, polyol ethers, resins having a polar group on the side chain, sugars or sugar derivatives, urea compounds, and inorganic salts. is injected into at least the surface layer of the wood, and then naturally dried. In the present invention, it is preferable that raw wood or raw wood in an undried state is processed into a predetermined shape, and the chemical agent is injected into at least the surface layer of the wood within two months from the processing without artificial heat drying. Alternatively, an agent composed of at least one selected from polyols, polyol ethers, sugars or sugar derivatives, urea compounds, and inorganic salts may be injected into at least the surface layer of the wood without being mixed with the resin component. preferable.

According to the present invention, the lumber is dried without being heated after injecting a predetermined agent (moisturizing agent) into the lumber, so that the lumber can be remarkably improved in moisture retention.

(1) Wood The type of wood used in the present invention is not particularly limited, and conifers such as cypress, white cypress, Japanese cypress, white cedar, Japanese cedar, Douglas fir, Japanese hemlock, Japanese red pine, black pine, larch, Douglas fir, spruce, Sakhalin fir, Ezo spruce, etc. , chestnut, zelkova, beech, maple, and sawtooth oak can all be used, but the characteristics of the present invention are particularly effectively exhibited in hemlock, cypress, cedar, bay cypress, cypress, and the like.
It is preferable that the wood is processed into a predetermined shape from raw wood or raw wood in an undried state prior to injection of a predetermined chemical (humectant). After this processing, artificial heat drying may be performed, but as long as a predetermined amount of the chemical can be injected, it is preferable to inject the chemical without artificial heat drying. When the artificial drying is not carried out, it is possible to leave it for a long period of time under non-humidified conditions, ie, natural drying (or natural drying), but it is preferable not to leave it for a long period of time. When artificial drying is not performed, the period from processing to drug injection can be, for example, within 2 months, preferably within 1 month, more preferably within 2 weeks, and even more preferably within 1 week.

The moisture content of wood at the time of chemical injection is, for example, 25% by mass or more, preferably 50% by mass or more, and more preferably 65% by mass or more. The water content is, for example, 90% by mass or less, preferably 80% by mass or less.

Incidentally, the water content is a value defined by the following formula (1). For measuring the moisture content, a resistance wood moisture meter, a high frequency wood moisture meter, etc. may be used. ”.
Moisture content (%) = (weight before drying (W ₁ ) - total dry weight (W ₀ )) / total dry weight (W ₀ ) x 100 (1)

Incidentally, the moisture content in the entire thickness direction of the lumber may be within the above range at the time of chemical injection. However, in the case of a large-diameter material, at least 8 mm or more, preferably 10 mm or more, more preferably 15 mm or more from the surface, and in the case of a thin plate material, preferably 10% or more, more preferably 15% or more of the total plate thickness is the water content. It may be in the range of ratios.

In the above processed lumber, the surface layer may or may not be subjected to an insizing treatment prior to chemical injection, as required. By applying the incising treatment, the moisturizing agent can be infiltrated efficiently in a short time. The pitch of the incising is not particularly limited, and the density of the wood differs depending on the tree species, or whether the surface of the wood to be treated is the core or sapwood, etc. It may be determined appropriately each time in consideration of time and the like.

Although the depth of the insizing is not particularly limited, it is preferable to dry the surface layer to 8 mm or more as described above in the present invention. However, even if the incising depth is limited to about 5 to 7 mm, drying and infiltration can be greatly accelerated compared to the case where incising is not applied.

When the wood to be treated is a relatively thin board or consists only of sapwood, drying and dimensional stabilizer infiltration can be efficiently performed without insizing treatment. It is desirable to apply an insizing treatment to the exposed portion to promote drying and infiltration.

Types of wood processing include cutting to adjust size and shape, joint processing such as dovetails and sickles using chisels and precut machines, joint processing, groove and decorative engraving, dowel processing, and metal fittings. This includes processing such as drilling pilot holes. It should be noted that it may be processed to the final shape before the injection of the drug, or it may be rough processed before the injection of the drug and processed to the final shape after the injection of the drug.

(2) Chemical agent (moisturizing agent) injection In the present invention, a predetermined chemical agent is injected (infiltrated) into the lumber prepared as described above. The prescribed agent functions alone as a moisturizing agent for wood, and does not impair the texture of wood. That is, when the humectant is injected into the lumber prepared as described above, the humectant is quickly infiltrated into the voids of the timber, and the retention rate of the humectant can be increased.

There are no particular restrictions on the specific conditions for injecting the chemical agent into the wood, and the usual conditions used when injecting preservatives etc. may be applied. For example, the chemical agent may be diluted with an appropriate diluent (such as water). It is possible to prepare an infusion solution prepared using this infusion solution, and to use this infusion solution, immersion treatment, warm/cold bath treatment, reduced pressure injection treatment, pressurized injection treatment, etc. can be adopted. may However, in order to efficiently inject the medicine in a short period of time, it is desirable to employ pressurized injection processing. In the pressurized injection treatment, the pressure condition is not particularly limited, but the pressure is preferably 0.39 MPa or more in order to complete the infiltration to a depth of at least about 8 mm from the surface layer or about 10% of the total plate thickness in a short time. (4 kgf/cm ² or more), more preferably 1.47 MPa or more (15 kgf/cm ² or more). Also, this pressure may be, for example, 2 MPa or less.

The amount of the moisturizing agent to be injected (the amount of the infusion solution) is preferably 10 kg/m ³ or more, more preferably about 100 kg/m ³ or more, in order to reliably enhance the moisturizing effect of the final product. Incidentally, the amount of the moisturizing agent (the amount as the injection solution) may be, for example, 800 kg/m ³ or less.
The injection amount is the total amount including diluent components such as a solvent (e.g., water), and in the case of containing preservatives and termite-preventing agents described later, it is the amount of the entire chemical solution including them, It is a value defined by the following formula (2).
Injection amount = (weight of wood after injection - weight of wood before injection) / wood volume (2)

In the present invention, it was confirmed that the following chemicals are effective in increasing the moisture retention of wood by injecting them directly into wood and allowing them to dry naturally. That is, agents that can be used as moisturizing agents in the present invention include polyols such as glycerin, 1,3-butanediol, alkylene glycols (ethylene glycol, propylene glycol, butylene glycol, etc.); polyalkylene glycols (polyethylene glycol, polypropylene glycol, polybutylene glycol, etc.), polyoxyalkylene alkyl ether (polyoxyethylene tridecyl ether, etc.), polyol ethers such as polyoxyalkylene alkyl aryl ether (polyoxyethylene nonylphenyl ether, etc.); hydroxyl group, carboxylic acid ester group , resins having polar groups such as carboxylic acid amide groups in side chains (e.g., curable resins such as phenolic resins; polyvinyl alcohol, polyvinylpyrrolidone, vinyl resins such as vinyl acetate); polyoxyethylene sorbitan monostearate, sorbitan sugars or sugar derivatives such as monooleate and D-glucose; urea compounds such as urea and methylol urea; inorganic salts such as alkaline earth metal halides such as calcium chloride, magnesium chloride and barium chloride; Alternatively, two or more of them can be used in appropriate combination. Particularly preferred moisturizing agents are moisturizing agents other than resin components, such as polyols, polyol ethers, sugars or sugar derivatives, urea compounds, inorganic salts, etc., for the purpose of preventing wood from losing its natural texture. , and most preferably polyols, urea compounds, and the like. Moisturizers other than these resin components are preferably injected into the wood without being mixed with the resin components. Even moisturizing agents (especially polyalkylene glycols) other than the resin components are sufficiently retained by the voids in the wood, and are difficult to escape from the wood even after the next drying process, and sufficiently improve the moisturizing properties of the wood. can be done.

When polyols and urea compounds are combined to form a moisturizing agent, the ratio of the amount of active ingredients (based on mass) (polyols/urea compound) is, for example, 0.1/1 or more, preferably 0.2/1 or more. , more preferably 0.3/1 or more, for example, 10/1 or less, preferably 5/1 or less, more preferably 3/1 or less.

The concentration of the moisturizing agent in the injection solution is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and for example, 30% by mass or less, preferably 20% by mass or less. , more preferably 10% by mass or less.

The amount of the active ingredient of the moisturizing agent (the amount excluding the diluent; also referred to as absorption amount) per cubic ^meter of lumber after injection and after natural drying, which will be described later, is, for example, 1 kg or more, preferably 10 kg or more. 100 kg or less.

It is preferable to inject an antiseptic agent or an anti-termitant agent at the time of injecting the moisturizing agent, because the moisturizing property can be improved and antiseptic treatment or anti-termite treatment can be performed. There are no particular restrictions on the preservatives and termiticides, and all known agents can be used. thiazolyl)-1H-benzimidazole, 2-(4-thiocyanomethylthio)-benzothiazole, 8-oxyquinoline copper aromatic quinoline derivative, 1-[2-(2',4' aromatic triazole derivative -dichlorophenyl)-4-propyl-1,3-dioxolan-2-yl-methyl]-1H-1,2,4-triazole, 1-[2-(2′,4′-dichlorophenyl-1,3-dioxolane- 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, and copper compounds such as cupric oxide. is not limited to

Typical termite-preventing agents include carbamate compounds such as fenocarb and carbaryl, pyrethroid compounds such as tralomethrin, permethrin and bifenthrin, ethofenprox, silafluofen, imidacloprid, acetamiprid, boric acid, and higher quaternary ammonium salts. are exemplified, but are not limited to these.

It is preferable to dilute the antiseptic agent, anti-termite agent, etc. with the above moisturizing agent with a diluent (such as water) to form an infusion solution, and inject this infusion solution into the wood. The concentration of the antiseptic or termiticide in the injection solution is, for example, 0.1% by mass or more, preferably 0.5% by mass or more, more preferably 1% by mass or more, and for example, 30% by mass or less, preferably is 20% by mass or less, more preferably 10% by mass or less.

The amount of active ingredients of preservatives and termite-preventing agents (the amount excluding the diluent; also referred to as absorption amount) per ^cubic meter of lumber after injection and natural drying, which will be described later, is, for example, 1 kg or more, preferably 10 kg or more. Yes, for example, 100 kg or less.

Further, in the present invention, in addition to the antiseptic agent and termiticide, it is also possible to inject, for example, a fire preventive agent, a flame retardant agent, etc., as required.

(3) Drying Wood that has been injected with chemicals is then dried. In this drying, it is important to perform natural drying (also referred to as natural drying) without performing artificial heat drying. When the injected wood is heated, the moisturizing effect of the moisturizing agent is lost. Natural drying includes all drying without artificial heating, and is not limited to outdoor drying, and may be indoor drying. Outdoor drying may include drying under a rain cover, drying in the shade, and drying in the sun.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples, and can be modified appropriately within the scope that can conform to the gist of the above and later descriptions. It is of course possible to implement them, and all of them are included in the technical scope of the present invention.

Example 1
After sawing, a test piece of 20 mm square and 20 mm long was cut out from the cedar material which had been placed in a laboratory at a temperature of about 20° C. and a relative humidity of about 40% for several days. To this test piece, "Maytrek (registered trademark) ACQ" (a copper-alkylammonium compound-based wood preservative manufactured by Koshii Preserving Co., Ltd.) as an antiseptic/termiticide, urea as a moisturizing agent, and 1,3- An injection solution containing butanediol (copper/alkylammonium compound concentration: 4% by mass, urea concentration: 5% by mass, 1,3-butanediol concentration: 2% by mass; diluent: water) was injected under reduced pressure. In the examples and comparative examples, the antiseptic/termiticide and the moisturizing agent are collectively referred to as drugs. The treated wood was produced by air-drying the test piece into which the chemical was injected. The total injection amount of the antiseptic/termiticide and moisturizing agent as a working liquid (diluted with water) was 700 kg/m ³ with respect to the entire wood.

Example 2
The procedure was the same as in Example 1, except that no antiseptic/termiticide was injected.

Comparative example 1
The same procedure as in Example 1 was carried out except that the test piece into which the antiseptic/termiticide and moisturizing agent had been injected was artificially heated and dried at a temperature of 105°C for 72 hours.

Comparative example 2
The same procedure as in Example 2 was carried out, except that the test piece into which the moisturizing agent had been injected was artificially heat-dried at a temperature of 105°C for 72 hours.

Comparative example 3
The procedure was the same as in Example 1, except that the antiseptic/anticide and moisturizing agent were not injected.

Comparative example 4
The procedure was the same as in Comparative Example 1, except that the antiseptic/anticide and moisturizing agent were not injected.

Test Examples The treated wood obtained in Examples 1-2 and Comparative Examples 1-4 was treated with water (relative humidity 100%), saturated potassium dichromate aqueous solution (relative humidity 93%), saturated potassium chloride aqueous solution (relative humidity 84%). %), saturated sodium nitrate aqueous solution (relative humidity 74%), saturated magnesium nitrate aqueous solution (relative humidity 53%), or saturated magnesium chloride aqueous solution (relative humidity 34%) in a sealed container, and the change in the moisture content of the treated wood surface examined. Within about 30 days, the moisture content of the treated wood converged to a range that varied depending on the relative humidity. Table 1 shows the water content values after convergence.

As shown in Table 1, when no specific moisturizing agent was injected, the moisture retention was equivalent to that of general wood regardless of drying conditions (Comparative Examples 3 and 4). Moreover, even if a specific moisturizing agent was injected, the moisture retention was equivalent to that of general wood when artificially heated and dried (Comparative Examples 1 and 2). High moisturizing properties could be demonstrated for the first time by injecting a specific moisturizing agent and drying naturally (Examples 1 and 2).

Claims (3)

An injection liquid containing urea and 1,3-butanediol at a urea concentration of 5% by mass or more and a 1,3-butanediol concentration of 2% by mass or more as a moisturizing agent is applied to the surface layer of wood and parts other than the surface layer. A method for producing lumber excellent in moisture retention, characterized in that the equilibrium moisture content of the naturally dried lumber is 20% or more (as a value at a relative humidity of 74%) after injecting in a depressurized method, followed by natural drying. . An injection solution containing urea and 1,3-butanediol as moisturizing agents at a urea concentration of 5% by mass or more and a 1,3-butanediol concentration of 2% by mass or more is prepared without mixing the injection solution and the resin component. After injecting it into the surface layer of the wood and the part other than the surface layer by a decompression method, it is naturally dried, and the equilibrium moisture content of the naturally dried wood is 20% or more (as a value when the relative humidity is 74%). A method for producing lumber with excellent moisture retention, characterized by: 2. Raw wood or raw wood in an undried state is processed into a predetermined shape, and the infusion liquid is injected within two months from said processing without artificially heat-drying the processed wood (excluding polished logs). A method for producing wood according to .