JPH02116510A - Manufacture of modified lumber - Google Patents

Abstract

PURPOSE:To manufacture modified lumber which possesses excellent noncombustibility, dimensional stability, wood preserving properties and dynamic strength and is provided with water resistance and moisture resistance, by a method wherein curing treatment is performed in the middle of impregnation treatment, in a manufacturing method of the modified lumber generating/fixing a water-insoluble and noncombustible inorganic matter within a lumber structure by infiltrating separately at least two kinds of aqueous solutions of water-soluble inorganic matters. CONSTITUTION:The title method is constituted so that curing treatment is performed in the middle of impregnation treatment, in a modified lumber manufacturing method wherein a water-insoluble and noncombustible inorganic matter is generated/fixed within a lumber structure by infiltrating individually at least two kinds of aqueous solutions of water-soluble inorganic matters which cause to generate the insoluble and noncombustible inorganic matter by mixing up with each other, into raw material lumber, which is going to modify. It is preferable further that the curing treatment is performed by adding at least a kind of physical stimulation out of an ultrasonic vibration, microwave heating pressurization and warming. Although reaction of an unreacted ion contained into the lumber to the insoluble and noncombustible inorganic matter is accelerated, a large quantity of the insoluble and noncombustible inorganic matters are generated and fixed finally within the lumber and improvement in the other properties are performed also, water resistance and moisture resistance are improved especially, by performing curing treatment in the middle of infiltration treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing modified wood used as housing equipment, building materials, etc.

[Conventional technology]

As a method for modifying wood, research has been conducted on methods to impart flame retardancy (fire retardancy), dimensional stability, rot and insect repellency, mechanical strength, surface hardness, etc. by producing insoluble and nonflammable inorganic substances in wood. , has been developed.

In general, modification methods for imparting flame retardancy to wood are broadly classified based on the following flame retardant mechanisms.

(a) Coating with inorganic substances (b) Promotion of carbonization (inhibition of chain reaction in C1 flaming combustion (d) Generation of nonflammable gas (el) Heat absorption due to decomposition and release of crystal water (f) Insulation by foam layer As explained below, the modification method of incorporating an insoluble non-flammable inorganic substance is an excellent method that can also be expected to have effects such as (b), (C1, (dl), etc., depending on the type of inorganic substance, in addition to the above (al). Moreover, once this insoluble, nonflammable inorganic substance is fixed in the wood structure, there is little risk of it being released from the wood, so there is little worry that its effects will diminish.

In the above, coating with an inorganic material (Al) means that even if the material is flammable, it can be made flame retardant by combining it with a nonflammable inorganic material at an appropriate blending ratio. For example, , the conventionally known wood chip cement board is made by mixing combustible wood with non-combustible cement at a weight ratio of about 1:1 and forming it into a board shape.
Recognized as a quasi-noncombustible material by IS.

The mechanism of carbonization promotion in mountains is as follows.

In other words, when wood is heated, it thermally decomposes and generates flammable gas, which causes flaming combustion. At this time, if phosphoric acid or boric acid is present, the thermal decomposition, or carbonization, of the wood is promoted. A carbonized layer is quickly formed. This carbonized layer acts as a heat insulating layer and provides a flame retardant effect, so if the insoluble nonflammable inorganic substance contains a phosphoric acid component or a boric acid component, the flame retardant effect of this modified wood will be even higher. .

The inhibition of the chain reaction in flaming combustion (C) is contributed by halogen, and as a result of the halogen acting as a chain transfer agent in the radical oxidation reaction in the flame, the oxidation reaction is inhibited. This is the mechanism by which the flame retardant effect occurs. Therefore, if the insoluble nonflammable inorganic substance contains a halogen, these effects can also be obtained.

Finally, the generation of nonflammable gas (dl) will be explained.

This is because compounds such as carbonates and ammonium salts generate nonflammable gases such as carbon dioxide, sulfur dioxide, and hydrogen halides through thermal decomposition, but these gases dilute flammable gases and prevent combustion. It is. Therefore, if the insoluble nonflammable inorganic substance contains something that can generate the above-mentioned nonflammable gases, such as carbonate, a flame retardant effect due to this mechanism can also be obtained.

Next, the antiseptic and insect repellent effects of wood containing this insoluble, noncombustible inorganic substance will be explained. When fungi cause wood to rot, mycelium first invades the inner cavity of the wood.
The presence of foreign matter in the internal cavity of the wood prevents mycelium from entering the wood, and as a result, the wood becomes less susceptible to decay. The foreign matter in the wood lumen does not have to be a particularly antiseptic agent (preservative), and may be anything as long as it does not provide nutrients for fungi. The same applies to insect prevention as to preservatives.

However, it is acceptable for foreign substances to have a medicinal effect; for example, it is preferable to use substances that are poorly digestible or indigestible to insects, or substances that have a repellent effect. Therefore, if an insoluble, nonflammable inorganic substance is included in the inner cavity of wood, it is effective for preventing wood from rotting and insects.

Furthermore, regarding the dimensional stability and mechanical strength of wood, for example, if wood is swollen with water and some substance can be fixed in the wood cell walls in that state, both of the above properties will be improved due to the bulk effect. In other words, if the inside of the wood cell wall is occupied by the filler, the wood itself is less likely to expand or contract, and at the same time, various mechanical strengths are improved. Here, as the immobilizing substance, an inorganic substance that is difficult to dissolve in water can be used, so if an insoluble incombustible inorganic substance is immobilized in the wood cell wall, such an effect can be obtained.

Finally, regarding the hardness (surface hardness) of wood, in general,
In order to increase the hardness of wood, it is sufficient to fill the voids such as conduits inside the wood and the cell walls of the wood with hard substances such as inorganic substances. The effects of reinforcement and increased hardness can be obtained. Here, it would be more effective if inorganic substances were generated in the leaves on the surface layer of the wood.

As described above, the method of incorporating insoluble, nonflammable inorganic substances is very effective in improving the N fuel ratio and other aspects of wood, but it has the following problems.

Generally, for example, if an insoluble, nonflammable inorganic substance is directly dispersed in a solvent such as water, and wood is immersed in this dispersion (treatment liquid) to allow the liquid to penetrate into the wood, most of the material that penetrates is water. This results in only solvents such as This is because the narrowest part of the passage through which the treatment liquid permeates into the wood is the pit membrane run, and the pore diameter here is approximately 0.1μ layer. The particle size of the insoluble, nonflammable inorganic particles that are dispersed particles is usually 0.1
This is because it is much larger than 1.

Therefore, the inventors have first developed a method that can solve this problem. That is, two types of aqueous solutions containing separately cations and anions (referred to as "cation-containing treatment liquid" and "anion-containing treatment liquid" in this order) that react to produce an insoluble nonflammable inorganic substance when mixed are prepared. , a method for manufacturing modified wood in which raw material wood is impregnated with both ions in order to cause both ions to react inside the wood, thereby fixing the insoluble and nonflammable inorganic substance (Japanese Patent Application Laid-Open No. 61-246003)
It is. In this way, extremely large amounts of insoluble, nonflammable inorganic substances can be efficiently incorporated into the wood.

[Problem to be solved by the invention]

However, it has been found that there is still room for improvement in the water resistance and moisture resistance of the modified wood obtained as described above.

In view of these circumstances, the present invention provides a method for producing modified wood that has excellent flame retardancy, two-dimensional stability, antiseptic and insect repellent properties, mechanical strength, etc., as well as high water resistance and moisture resistance. The challenge is to provide the following.

[Means to solve the problem]

In order to solve the above problems, the present invention impregnates the raw material wood to be modified with an aqueous solution of two or more water-soluble inorganic substances that produce insoluble incombustible inorganic substances when mixed into the wood structure. This is a method for producing modified wood in which the same insoluble, nonflammable inorganic substance is produced and fixed, and a curing treatment is performed during the impregnation treatment.

Furthermore, the curing treatment is preferably carried out by applying one or more of the following physical stimuli: ultrasonic vibration, microwave heating, pressurization, and heating.

[For production]

By performing curing treatment during the impregnation process, the reaction of unreacted ions contained in the wood to insoluble non-flammable inorganic substances is promoted, and a large amount of insoluble non-flammable inorganic substances are eventually generated and fixed in the wood. be done.

As a result, other properties are improved, particularly water resistance and moisture resistance.

〔Example〕

The raw material wood for modification used in this invention is not particularly limited, and raw wood logs,! ! Examples include J material products, sliced veneer 5 plywood, etc. There are no limitations on the tree species, etc.

Insoluble, nonflammable inorganic substances that are generated in wood and dispersed and fixed in the wood structure are not particularly limited, but include, for example, borates, phosphates, hydrogen phosphates, carbonates,
Sulfates and hydrogen sulfates.

Examples include silicates, nitrates, hydroxides, and the like. Two or more types of these inorganic substances may coexist in the wood.

Further, one type of insoluble nonflammable inorganic substance may contain two or more types of each of the cation and/or anion moieties described below.

More specifically, the elements of the cation part of the insoluble nonflammable inorganic substance include alkali metals such as Na, Mg,
Alkaline earth metals such as Ca, Sr, Ba, Zn and A
I is mentioned as a good example, but for example, Mn, Ni,
It may be a transition element such as Cd or a carbon group element such as Si or Pb, and is not particularly limited.

As the anion constituting the insoluble nonflammable inorganic substance, Bo
g, PO,, COs, SO4 and OH anions are given as examples. In particular, the B OgPO4 anion has the effect of the flame retardant mechanism 0)), and the co anion has the effect of the same (dl), so the - layer is preferable.However, it is not limited to these, for example ,O,No,.

It may be 5if4, 5iCh, F, CI, Br7nior7, etc.

The above cations and anions are arbitrarily selected depending on the composition of the desired insoluble, nonflammable inorganic substance to be produced in the wood, and by dissolving the water-soluble inorganic substances containing each of these ions in water separately, the desired A cation-containing treatment liquid containing cations and an anion-containing treatment liquid containing desired anions are prepared.

In addition, the above-mentioned OH anion etc. may be used alone, or may be included together in a cation-containing treatment liquid and/or an anion-containing treatment liquid containing other anions.
It may be prepared to produce apatite or the like in wood.

Examples of inorganic substances that dissolve in water to produce the above-mentioned desired cations include MgClt, MgBr*, MgSO4.Hi
O, Mg (NOI)! ' 6Hi O, CaC
1z, CaBrt, Ca (Not)x + B
aCl・2Hi Or Ba B rz + 13
a (Now)t + AlCl5, AlBr*
, Alt (SO4)l , AI (Now)t
Examples include ' 9 Hi O, Z n C1, etc., but are not limited thereto. Examples of the inorganic substance that dissolves in water to produce the desired anion include Na z COs + (NH4)I C
ot, Hi SO4, Nag SO4+ (NH4
)g SO4, Hi PO4, Na, HPO,, (NH
,)! HPO,,H,BO,,Na BO,,NH4
BO, etc., but are not limited thereto. Each of the above water-soluble inorganic substances may be used alone, or a plurality of types may be used in combination in one treatment liquid within the range where a uniform aqueous solution can be formed without reacting with each other.

One of the above cation/anion-containing treatment liquids (first liquid) is impregnated into the wood by immersing the raw material wood in the same treatment liquid. At this time, prior to the impregnation treatment, it is recommended to subject the raw material wood to a water saturation treatment so that the wood is sufficiently saturated with water. This is because the ions in the first liquid can diffuse quickly using the water in the wood as a medium, and the processing time can be shortened. Here, the above-mentioned water saturation treatment method includes underwater wood storage, steaming, impregnation under reduced pressure, impregnation under pressure, etc.
There are no particular limitations.

Next, the wood is similarly impregnated with a treatment liquid (second liquid) containing ions that react with the first liquid to generate insoluble nonflammable inorganic substances, thereby generating the same insoluble nonflammable inorganic substances inside the wood.

After that, if necessary, add a third liquid, a fourth liquid...
etc. may be prepared and impregnated repeatedly to densify the product layer. The cation/anion-containing side treatment liquids used at this time may be of the same type or different types, and their concentration is not particularly limited. Further, the impregnation treatment method for the first liquid, the second liquid, etc., the impregnation treatment time, etc. are not particularly limited, and for example, impregnation may be carried out under reduced pressure or impregnation by coating. can. In addition, when impregnating the first liquid under reduced pressure, it is not necessary to perform the above-mentioned water saturation treatment.

The above is the impregnation treatment, but a feature of the present invention is that a curing treatment is performed during the impregnation treatment. The curing treatment is not particularly limited as long as it promotes the reaction of unreacted ions impregnated in the wood to produce an insoluble, nonflammable inorganic substance, and the method thereof is not particularly limited. Specifically, this can be carried out by applying physical stimulation such as ultrasonic vibration, microwave heating, pressurization, and heating.

More specifically, the above-mentioned ultrasonic vibration can be carried out using any machine 3 (for example, an ultrasonic cleaner, etc.), and is preferably carried out while applying heat. It is preferable to set conditions such that microwave heating can be carried out for a long period of time at a reduced output so that the temperature of the wood does not rise too much and reaches an appropriate temperature. In the case of pressurization, if the pressure is too high, the equipment will become large-scale and the wood structure may be compressed and destroyed, so it is appropriate to carry out the pressurization under a pressure of about 10 kg/cJ or less, for example. Furthermore, regarding heating, it is usually preferable to set the temperature to 40 to 90°C. However, each curing treatment condition is not limited to the upper side, and for example, the treatment time can be set appropriately to ensure that these reactions are sufficiently carried out depending on the amount of unreacted ions contained in the wood. good. In addition, when performing the above-mentioned microwave heating, warming, etc., it is preferable to seal the wood by wrapping it etc. so that the moisture in the wood does not evaporate.

The above-mentioned curing treatment can be carried out any number of times at any stage during the impregnation process, and is carried out in a state where both cations and anions capable of producing insoluble, non-flammable inorganic substances are present in the wood. Specifically, for example, in the following order:
Impregnation and curing treatments can be performed.

・Anion impregnation → cation impregnation → curing → anion impregnation ・Cation impregnation → anion impregnation → curing → cation impregnation ・Cation impregnation → anion impregnation → cation impregnation → curing −
Anion impregnation/cation impregnation - Anion impregnation - Curing - Cation impregnation -
Anion impregnation - Curing/Anion impregnation - Cation impregnation → Anion impregnation → Cation impregnation → Curing → Impregnation beyond anion impregnation! After insoluble and nonflammable inorganic substances are generated and fixed in the wood by the raw treatment, the surface of the wood is washed with water, if necessary, and dried to obtain modified wood. In addition, in order to further improve the water resistance and weather resistance of the wood, leaching treatment may be performed as necessary to remove soluble unreacted ions or by-products remaining in the wood 4t4.

Next, regarding more detailed embodiments of this invention,
Although explained in conjunction with a comparative example, it goes without saying that the method for producing modified wood according to the present invention is not limited to the following example.

Example 1 - A 3-thick rotary veneer made of agathis wood is immersed in water,
A water saturation treatment was performed under a reduced pressure of approximately 0 Torr to sufficiently impregnate the interior of the wood with water.

The obtained saturated veneer was immersed in an aqueous solution (first solution) containing 3.5 mol of hydrogen phosphate and 4.0 mol of orthoboric acid per 11 parts of water, and then 2.0 mol of barium chloride per 11 parts of water. and orthoboric acid2.
It was immersed in an aqueous solution (second liquid) containing 0 mol. Thereafter, the treated wood was sealed and cured at a constant temperature of 60° C. for 12 hours. Finally, 8.0 mol of diammonium hydrogen phosphate and 5.0 mol of orthoboric acid per 11 mol of water. Qm
The veneer was immersed in an aqueous solution (third liquid) containing OL, and then the same veneer was washed with water and dried to obtain a modified wood.

Examples 2 to 5 - In the same manner as in Example 1 above, impregnation treatment using the dipping treatment liquid shown in Table 1 and curing treatment were performed to obtain modified wood. In addition, the microwave heating in Example 3 was performed on sealed wood at a high frequency output of 180 W and an oscillation frequency of 2450 W.
It was set to run at MHz for 15 minutes.

Comparative Example 1.2 Except for not performing curing treatment during impregnation treatment,
Impregnated with the treatment liquid shown in Table 1 in the same manner as in the above example,
Obtained modified wood.

The modified wood obtained above was examined for its impregnation rate with insoluble and nonflammable inorganic substances, water resistance, and moisture resistance. The impregnation rate of the above inorganic substance is the weight ratio of the insoluble incombustible inorganic substance to the weight of bone-dry wood. Regarding water resistance, water resistance A test (80℃, 1 hour hot water immersion - 60℃, 2 hours drying) 80
After immersing the wood in hot water for 1 hour at -60℃ and drying for 2 hours, the wood was kept completely dry and the weight loss rate was determined, which was 3%.
If it was below, and if it exceeded 0.3%, it was evaluated as △. Humidity resistance: 60℃, 90%RH, 48 hours +20℃,
65% RH, 24 hours - -20°C.

After 24 hours → 20℃, 65% RH, 24 hour moisture resistance test, keep it in an absolutely dry state and check the weight loss rate.If it is less than 5%, if it exceeds 0.5%, it will be evaluated as poor. did.

The above results are also shown in Table 1.

As shown in Table 1, the modified wood of the examples obtained by curing during the impregnation treatment contained a larger amount of insoluble, nonflammable inorganic substances than the comparative examples, and had a high degree of water resistance and It was found to be moisture resistant. In addition, the modified wood had excellent N flammability, mechanical strength, dimensional stability, antiseptic and insect repellent properties, and had a good appearance with no loss of wood texture.

[Effects of the Invention] According to the method for producing modified wood according to the present invention, modified wood having high water resistance and moisture resistance can be efficiently obtained. At the same time, this modified wood has excellent flame retardancy, dimensional stability, antiseptic and insect repellent properties, mechanical strength, and appearance.
It has advanced performance that makes it ideal as a building material.

Agent: Patent Attorney Takehiko Matsumoto

Claims (1)

[Scope of Claims] 1. Raw material wood to be modified is individually impregnated with an aqueous solution of two or more water-soluble inorganic substances that produce insoluble non-flammable inorganic substances when mixed, so that the same insoluble non-flammable inorganic substances are produced within the wood structure. A method for producing modified wood in which inorganic substances are generated and fixed, characterized in that a curing treatment is performed during the impregnation treatment. 2. The curing treatment according to claim 1, wherein the curing treatment is performed by applying a physical stimulus, and the physical stimulus is at least one of ultrasonic vibration, microwave heating, pressurization, and heating. Process for producing modified wood.