JPH0482702A - Production of modified wood - Google Patents

Abstract

PURPOSE:To ensure excellent antiseptic, moth-proof and flame-retardant proper ties, etc., and enhance dimensional stability, by impregnating a raw material wood with a component for forming an insoluble hardened resin at the time of impregnating the material wood with a cation- and an anion-containing treating liquid, and fixing the insoluble hardened resin in the texture of the wood. CONSTITUTION:At the time of impregnating a raw material wood with a cation impregnating treating liquid and an anion impregnating treating liquid, the wood is impregnated also with an aqueous solution containing a component for forming an insoluble hardened resin. The wood is then left to stand in a low-oxygen atmosphere, and is heated to a high temperature, whereby the insoluble hardened resin is formed and fixed in the texture of the wood. The cation impregnating treating liquid contains at least one cation selected from the group consisting of Mg, Ba, Ca, Al and Zn cations. The anion impregnating treating liquid contains one anion selected from the group consisting of BO3, PO4, CO3, SO4 and OH anions. The aqueous solution containing the component for forming the insoluble hardened resin contains an aminotriazine or guanidine, an acrylamide, formalin and an acid.

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 wood modification method, by incorporating insoluble and nonflammable inorganic substances into wood, flame retardance (fire retardance), dimensional stability,
Research and development are being conducted on methods to impart antiseptic and insect repellent properties, mechanical strength, surface hardness, etc.

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 (C) Inhibition of chain reaction in flaming combustion (d)
Generation of nonflammable gas (el) Heat absorption due to decomposition and release of crystallized water (f) Heat insulation by foam layerHere, the modification method of incorporating insoluble nonflammable inorganic substances into wood is as explained below. ), depending on the type of inorganic substance, (b), (C1, (d)
This is an excellent method that can also be expected to have effects such as Moreover, once the insoluble, nonflammable inorganic substance is fixed in the wood structure, there is little possibility that the melt will come out of the wood, so there is little worry that the above-mentioned effects will be diminished.

The flame retardant mechanisms described above (al to (d)) will be described in detail below.

The inorganic coating (a) means that even if the material is flammable, it can be made flame retardant by combining it with a nonflammable inorganic material in an appropriate mixing ratio. For example, conventionally known wood chip cement boards are made by mixing combustible wood with noncombustible cement at a weight ratio of about 3:1 to 1:10 and forming it into a board shape, which is semi-noncombustible according to JIS. Recognized as a material.

The mechanism for promoting carbonization in (b) is as follows. 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 of the wood, or carbonization, is promoted. , a carbonized layer is quickly formed. This carbonized layer acts as a heat insulating layer and produces a flame retardant effect. therefore,
When the insoluble nonflammable inorganic substance contains a phosphoric acid component or a boric acid component, the flame retardant effect becomes even higher.

(C) Inhibition of chain reactions in flaming combustion is contributed by halogens.In radical oxidation reactions in flames, halogens act as chain transfer agents, and as a result, oxidation reactions are inhibited. This is the mechanism by which the flame retardant effect occurs. Therefore, if the insoluble nonflammable inorganic substance contains a halogen, a flame retardant effect based on this mechanism can also be obtained.

(The mechanism of generation of nonflammable gases in dl is as follows. In other words, compounds such as carbonates and ammonium salts generate nonflammable gases such as carbon dioxide gas, sulfur dioxide gas, and hydrogen halides through thermal decomposition. This is a mechanism in which these gases dilute flammable gases and thereby hinder combustion. Therefore, if the insoluble nonflammable inorganic substance contains carbonates and other substances that generate nonflammable gases, this mechanism will prevent the combustion. A combustion effect is also obtained.

Next, we will explain how to make wood rot-proof and insect-proof.

When fungi cause wood to rot, it is essential that hyphae first invade the inner cavity of the wood. However, if foreign matter is present in the internal cavity of the wood, mycelia cannot invade, resulting in the wood becoming less susceptible to decay. The foreign matter in the wood lumen need not be a preservative (preservative), and may be anything as long as it does not provide nutrients for fungi. The same applies to insect repellent as preservative. Therefore, if an insoluble, noncombustible inorganic substance is included in the inner cavity of wood, the antiseptic and insect repellent properties of wood can be improved. However, the above-mentioned foreign substances are suitable as long as they have a medicinal effect; for example, it is preferable that they are poorly digestible, indigestible, or have a repellent effect on insects.

Additionally, dimensional stabilization and mechanical strengthening of wood will be discussed. If wood can be swollen with water and some substance can be fixed in the wood cell walls, dimensional stabilization and mechanical strengthening effects can be obtained due to the bulk effect. That is,
If the inside of the wood cell wall is occupied by filler, the wood itself will be less likely to expand or contract, and at the same time,
Various mechanical strengths are also improved. Here, as the immobilizing substance, inorganic substances that are difficult to dissolve in water can also be used. Therefore, if an insoluble nonflammable inorganic substance is fixed in the wood cell wall,
Dimensional stability and mechanical strength can be improved.

Finally, to explain how to improve the hardness (surface hardness) of wood, generally speaking, in order to increase the hardness of wood, you can stuff hard substances such as inorganic substances into the voids such as conduits inside the wood and into the cell walls of the wood. Therefore, by fixing insoluble, nonflammable inorganic substances in wood, the effects of reinforcing wood cells and increasing hardness can be obtained. In this case, it is more effective to generate inorganic substances intensively on the surface layer of the wood.

As described above, the method of incorporating insoluble and nonflammable inorganic substances is very effective in modifying wood including flame retardation, but conventionally it has had the following problems.

In general, even if an insoluble, nonflammable inorganic substance is directly dispersed in a solvent such as water, and wood is immersed in a treatment liquid made of this dispersion to allow the treatment liquid to penetrate into the wood, the treatment liquid will not penetrate. This is due to the following reason: The narrowest part of the path through which the treatment liquid passes when penetrating into the wood is the bit membrane run. However, the pore diameter here is about 0.
1 micron, whereas dispersed insoluble, non-flammable inorganic particles are typically much larger than 0.1 micron.

Therefore, a method was developed to solve this problem. That is, two types of aqueous solutions separately containing cations and anions that react with each other to produce insoluble nonflammable inorganic substances when mixed (hereinafter referred to as "cation-containing treatment liquid" and "anion-containing treatment liquid" in this order). is prepared by dissolving a water-soluble inorganic substance in water, and the raw wood is impregnated with a rainwater solution in order, and the above-mentioned ions are reacted in the wood, thereby producing an insoluble non-flammable inorganic substance. It is a manufacturing method (Japanese Patent Application Laid-Open No. 1983-246003)
(Refer to the publication number, etc.)

According to this method, insoluble noncombustible inorganic substances are not infiltrated as solid particles, but in the form of ions dissolved in a medium such as water, so impregnation is easy and extremely large amounts of insoluble noncombustible inorganic substances are infiltrated. It is possible to efficiently incorporate organic inorganic substances into wood. Therefore, it is possible to obtain modified wood with extremely excellent antiseptic, insect repellent, flame retardant properties, and the like.

Specifically, in this modification method, a cation-containing treatment liquid and an anion-containing treatment liquid are obtained by separately dissolving a water-soluble inorganic substance containing a predetermined cation and a water-soluble inorganic substance containing a predetermined anion in water. More specifically, a combination of treatment solutions containing a single water-soluble inorganic substance (a combination of single solution systems) is usually used.

For example, a cation-containing treatment solution containing Ca CI t and K.

By impregnating wood with an anion-containing treatment solution containing CO, or by impregnating wood with a cation-containing treatment solution containing A I C1m (NH
, ), an anion-containing treatment solution containing HPO4 is impregnated into wood to generate insoluble, nonflammable inorganic substances in the wood.

[Problem to be solved by the invention]

However, with this modified wood manufacturing method, although it is possible to obtain modified wood with excellent flame retardancy, antiseptic and insect repellent properties, in some cases, the improvement rate in terms of dimensional stability of the wood is low. There was a problem that the performance was low and sufficient performance could not be obtained.

Therefore, as a result of intensive studies to obtain modified wood with improved dimensional stability, the inventors discovered that, in addition to the above-mentioned insoluble nonflammable inorganic substance, by fixing an insoluble cured resin within the wood, the dimensional stability could be improved. They discovered that it is possible to obtain modified wood with improved properties, and have already filed a patent application for the method (see Japanese Patent Application No. 79803/1999). In this method, when raw wood is impregnated with a cation-containing treatment liquid and an anion-containing treatment liquid, an aqueous solution containing a component that produces an insoluble cured resin is also impregnated, and the insoluble cured resin is mixed with insoluble nonflammable inorganic substances in the raw wood structure. We are also trying to generate and fix it.

However, even with this method, modified wood having sufficient dimensional stability may not be obtained depending on the conditions for producing an insoluble cured resin within the wood, and optimization of the conditions has been awaited.

In view of these circumstances, it is an object of the present invention to provide a method that can efficiently obtain modified wood with further improved dimensional stability compared to modified wood obtained by conventional methods. .

[Means to solve the problem]

In order to solve the above problems, the method for producing modified wood according to the present invention is a combination of a cation-containing treatment liquid and an anion-containing treatment liquid that produce an insoluble, non-flammable inorganic substance by mixing the raw material wood to be modified. A method for producing modified wood in which the insoluble and nonflammable inorganic substance is generated and fixed in the raw material wood tissue by impregnating one of the two and then the other, the method comprising: impregnating the raw material wood with a cation-containing treatment liquid; When impregnating with the anion-containing treatment liquid, the raw wood is also impregnated with an aqueous solution containing components that produce an insoluble cured resin (hereinafter referred to as the "resin aqueous solution"), and the raw wood is left in a low-oxygen atmosphere. After that, by heating at a high temperature, the insoluble cured resin is also generated and fixed within the raw material wood structure.

The raw material wood for modification used in this invention is:
There are no particular limitations, such as raw wood logs, sawn timber products, sliced veneers,
Examples include plywood. There are no limitations on the tree species, etc.

In this invention, the insoluble and nonflammable inorganic substances (insoluble products) that are generated in wood and dispersed and fixed in the wood tissue are not particularly limited, but include, for example, borates,
Examples include various salts such as phosphates, hydrogen phosphates, carbonates, sulfates, hydrogen sulfates, silicates, nitrates, and hydroxides.

Among these salts, specific examples of carbonates include BaC0*, CaCO5, FeC0t, M
gCOx, MnCo! , N iCow , ZnCot
etc. Two or more of these may coexist in the wood. The insoluble, nonflammable inorganic substance within the wood may be fixed in the form of a reaction with wood cellulose.

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

In order to generate the above-mentioned insoluble non-combustible inorganic substance in the wood tissue, an aqueous solution prepared with a group of inorganic compounds constituting the cationic part of the insoluble non-combustible inorganic substance, that is, a cation-containing treatment liquid, and an anionic part constituting the insoluble non-combustible inorganic substance are used. An aqueous solution prepared with another group of inorganic compounds, that is, an anion-containing treatment solution, is separately and sequentially impregnated into the wood structure. The cation-containing treatment liquid and the anion-containing treatment liquid can be impregnated alternately once or multiple times. When impregnating multiple times, the impregnation may be performed not alternately but continuously.

The cation moiety of the insoluble nonflammable inorganic substance includes, for example, alkali metals such as Na and C;
Alkaline earth metals such as a, Ba, Mg, Sr, Mn,
Transition elements such as Ni and Cd, carbon group elements such as Si and Pb,
Examples include Zn and AA. Among these, Ca
, Ba, Mg, Zn and Al cations are preferred.

Examples of the anion portion of the insoluble nonflammable inorganic substance include B2O3 and BO.

, PO4, COs , So4, Not , OH, C1,
Examples include Br, F, ■ and OH. Among these, BO3, PO4, Co, , So.

and OH anions are preferred. Furthermore, among the anions, B2O3, Bog, and PO4 have the effect due to the mechanism (b), CO8 has the effect due to the mechanism (dl), and halogens such as Cj!, F, and Br have the effect due to the mechanism (C) and (d). ) effects can be expected from each mechanism.

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 separately dissolving the water-soluble inorganic substance containing each of these ions in water, A cation-containing treatment liquid containing desired cations and an anion-containing treatment liquid containing desired anions are prepared. However, the combination of the cation and anion is appropriately selected so that an insoluble incombustible inorganic substance is likely to be generated within the wood structure.

Inorganic substances that dissolve in water to produce the desired cations include MgClt, MgBrz, Mg5O, .H,
01Mg (Not)z-6H20, CaCf,
, CaBrz , Ca (Not)z , BaC/!
・2H20, B a B rz , B a (Not
)z, AlCl2. , Aj2Brx , Af2(S
o4)s, Al (Not)x ・9 Hz Ol
Examples include, but are not limited to, Z n C1. Examples of inorganic substances that dissolve in water to produce the desired anion include N a z COx,
(NH,), Co.

, Ht SO4, Na2SO2, (NH,)2 SO4
, Ht PO4, Nag HPO4, (NH,), HP
Examples include, but are not limited to, O4, Ht Bow, NaBOz, NH4Box, etc. 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.

The aqueous resin solution used in this invention is one that dissolves in water and is easily impregnated into wood, and after impregnation, polymerizes and hardens in the wood by performing an appropriate treatment to produce a resin that is insoluble in water. Although there are no particular limitations as long as the components are contained, for example, a mixed aqueous solution of at least one of aminotriazines and guanidines, at least one of acrylamides, formalin (formaldehyde), and an acid is preferable. Specific examples of components contained in such a mixed aqueous solution are not particularly limited, but examples of aminotriazines include melamine, ammeline,
Preferable examples include guanomelamine and melam; examples of guanidines include dicyandiamide, guanylurea, and guanidine; examples of acrylamides include acrylamide and methacrylamide; and examples of acids include phosphoric acid. When N-group-containing resins with flame retardant effects, such as melamine resins obtained by polymerizing and curing these components, are produced and fixed in wood, the dimensional stability of the resulting modified wood will of course improve. This is because it also leads to improved flame retardancy of modified wood.

Moreover, when phosphoric acid is used as the acid, the flame retardance of the modified wood is improved.

The impregnation treatment of the raw material wood with the above-described cation-containing treatment liquid, anion-containing treatment liquid, and aqueous resin solution is performed, for example, as follows.

First, one of the cation-containing treatment liquid and the anion-containing treatment liquid (first liquid) is impregnated into the wood by immersing the raw material wood in the same treatment liquid. After impregnating with the first liquid, a treatment liquid (second liquid) containing ions of a partner that reacts with the first liquid is similarly impregnated to generate insoluble and nonflammable inorganic substances inside the wood. Next, the wood is similarly impregnated with the resin aqueous solution (third liquid).

After the three liquids, the anion-containing treatment liquid, the cation-containing treatment liquid, and the resin aqueous solution are impregnated as described above, the fourth liquid, fifth liquid, sixth liquid, etc. are added as necessary. It may be prepared and impregnated repeatedly to densify the product layer. The cation/anion-containing treatment liquid and resin aqueous solution used at this time may be of the same type or different types, and their concentrations are not particularly limited. Impregnation treatment method for each liquid,
The impregnation treatment time is not particularly limited, and impregnation can be carried out under reduced pressure or by coating.

In addition, prior to the impregnation treatment with the first liquid, it is recommended that the raw material wood be subjected to a water saturation treatment so that the wood is sufficiently saturated with water. This is because the ions contained in the first liquid can be rapidly diffused using the water in the wood as a medium, and the processing time can be shortened. The water saturation treatment method is not particularly limited, but may be carried out by submerged wood storage, steaming, impregnation under reduced pressure, impregnation under pressure, or the like. In addition, the first
When the liquid is impregnated under reduced pressure, it is not necessarily necessary to carry out this water saturation treatment.

After the impregnation treatment, curing can be performed as necessary to promote the production reaction of insoluble and nonflammable inorganic substances.

The order of impregnation with the cation-containing treatment liquid, anion-containing treatment liquid, and resin aqueous solution is not particularly limited, but preferably, the resin aqueous solution is impregnated after the cation-containing treatment liquid and anion-containing treatment liquid are impregnated. is desirable. Although it is desirable to impregnate the cation-containing treatment liquid, anion-containing treatment liquid, and resin aqueous solution separately, it is preferable to impregnate with a solution that is a mixture of one of the cation-containing treatment liquid and anion-containing treatment liquid and the resin aqueous solution. You can.

After producing and fixing insoluble nonflammable inorganic substances in the wood through the above impregnation treatment, the surface of the wood is washed with water as necessary, dried, and the aqueous resin solution component impregnated into the wood is polymerized and hardened. A desired modified wood can be obtained by producing and fixing a cured resin together with the insoluble, nonflammable inorganic substance in the wood.

However, in this invention, the wood that has been impregnated as described above must be left in a low-oxygen atmosphere and then heated at a high temperature to generate and fix an insoluble cured resin within the structure of the raw wood. There is. Once the impregnated wood is left in a low-oxygen atmosphere, the resin aqueous solution components polymerize to form a straight resin.Then, by heating the wood at high temperature, the resin efficiently forms a tertiary resin with a high degree of crosslinking. This is because the dimensional stability of the wood is further improved since it is originally crosslinked and cured.

Methods for leaving impregnated wood in a low-oxygen atmosphere are not particularly limited, but include, for example, placing the wood in a vacuum tank and reducing the pressure of the air in the tank, or filling the tank with an inert gas such as nitrogen or argon. How to leave wood in a closed container,
etc. When the wood is left under reduced pressure, the degree of pressure reduction is not particularly limited, but it is preferably about 10 torr.The temperature at which the wood is then heated to a high temperature is not particularly limited, but for example, 100°C or higher is preferable. preferable. By performing such high-temperature heating,
It is also possible to dry the wood at the same time as the curing of the resin progresses.

In addition, in order to more efficiently polymerize and harden the resin aqueous solution components as described above, additives such as an initiator, a catalyst, and a curing agent may be added to the resin aqueous solution in advance, although they are not particularly limited. It is preferable to leave it there. As such additives, for example, when polymerizing the vinyl groups of the acrylamides, peroxides such as potassium persulfate and hydrogen peroxide are preferable, and when condensing the methylol groups of melamine resins, etc. is preferably an acid catalyst such as ammonium chloride or para-toluenesulfonic acid, but is not limited thereto.

[For production]

By generating and fixing insoluble nonflammable inorganic substances in the wood, and also generating and fixing insoluble cured resin,
The dimensional stability of the wood is further improved compared to the case where only insoluble, nonflammable inorganic substances are generated and fixed. Additionally, if the impregnated wood is left in a low-oxygen atmosphere and then heated at a high temperature, the insoluble hardened resin will be efficiently generated and fixed within the wood, further improving the dimensional stability of the wood. .

〔Example〕

Specific examples and comparative examples of the present invention are shown below, but the present invention is not limited to the following examples.

Examples 1 to 5 Agatis three cranes thick rotary veneer was boiled in hot water at 80°C to saturate it with water. The obtained veneer was sequentially immersed for 4 hours each in a cation-containing treatment solution (first bath) at 80°C and an anion-containing treatment solution (second bath) at the same temperature with the composition and concentration shown in Table 1 below. After that, the composition shown in Table 1 below
The veneer was immersed in a concentrated resin aqueous solution (third bath) at room temperature for 24 hours, then taken out from the resin aqueous solution, the surface was washed, and the veneer was placed in reduced pressure air at 10 torr. I left it alone. Thereafter, the modified wood of Examples 1 to 5 was obtained by heating and drying the veneer at 110°C.

1 Comparative Example 1 In Example 1, the impregnated veneer was once soaked at 10 to
Modified wood was obtained in the same manner as in Example 1, except that the treatment of leaving it in rr reduced pressure air was omitted.

The modified wood obtained in Examples 1 to 5 and Comparative Example was examined for dimensional stability and flame retardancy. Dimensional stability is determined by the following formula (a): ASE= ((D, -D) /D, ) X 100
-(al (where D represents the shrinkage rate of untreated wood and D represents the shrinkage rate of treated wood, respectively.) Anti-shrinkage ability ASE (%) was evaluated.Flame retardancy was evaluated according to JIS It was evaluated according to the method of A1321.The results are shown in Table 1.

As shown in Table 1, it can be seen that the modified wood according to the example has improved dimensional stability compared to the modified wood according to the comparative example. Regarding flame retardancy, all of the modified woods had grade 2 flame retardancy and were equivalent on the scale, but the modified woods of the Examples were superior to the Comparative Examples.

〔Effect of the invention〕

According to the method for producing modified wood according to the present invention, it is possible to efficiently obtain modified wood that has excellent antiseptic properties, insect repellency, flame retardancy, etc., and also highly excellent dimensional stability. The obtained modified wood has inorganic substances and resins impregnated and fixed inside the wood, so the wood texture is not impaired, and the wood has excellent appearance as well as the above-mentioned performance. Furthermore, the inorganic substance and resin are insoluble in water, and there is no fear that they will seep out of the wood due to water, moisture, etc., so the modified wood also has excellent water resistance and moisture resistance.

Agent: Patent Attorney Takehiko Matsumoto Concentrations represent monop to water 11.

Claims (1)

[Scope of Claims] 1 The raw material wood to be modified is impregnated with one of a combination of a cation-containing treatment liquid and an anion-containing treatment liquid that produces an insoluble non-flammable inorganic substance when mixed, and then the other is impregnated with the other. A method for producing modified wood in which the insoluble incombustible inorganic substance is generated and fixed in the raw material wood structure by impregnation, the method comprising: impregnating the raw material wood with a cation-containing treatment liquid and an anion-containing treatment liquid; It is also impregnated with an aqueous solution containing components that produce an insoluble cured resin.
A method for producing modified wood, characterized in that the raw material wood is once left in a low-oxygen atmosphere and then heated at a high temperature so that the insoluble cured resin is also generated and fixed within the structure of the raw material wood. 2. The cation-containing treatment liquid contains at least one selected from the group consisting of Mg, Ba, Ca, Al, and Zn cations, and the anion-containing treatment liquid contains BO_3.
2. The method for producing modified wood according to claim 1, which contains at least one selected from the group consisting of , PO_4, CO_3, SO_4 and OH anions. 3. An aqueous solution containing a component that produces an insoluble cured resin,
3. The method for producing modified wood according to claim 1, which contains at least one of aminotriazines and guanidines, at least one of acrylamides, formalin, and an acid.