JPH0357601A - Manufacture of modified wood - Google Patents

Abstract

PURPOSE:To obtain modified wood excellent in flame retardancy, rotproofness and mothproofness, dimensional stability, hardness and the like by a method wherein anion seeds and/or cation seeds which are left in wood after the production and fixation of insoluble and incombustible inorganic matter in wood tissue, are mixed so as to produce and fix another insoluble and incombustible inorganic matter. CONSTITUTION:Stock wood A is immersed in cation-containing processing liquid to as to impregnate the wood A with the first cation 11 and the first anion 12. When the wood A is impregnated with the second cation 21 and the second anion 22 by immersing the wood A in anion-containing processing liquid, the first cation 11 and the second anion 22 reacts with each other, resulting in producing and fixing insoluble and incombustible matter 4. Next, by immersing the wood A, to which said treatment is applied, in another cattion-containing processing liquid 3, which contains the third cation 31, in order to impregnate the wood A with the third cation 31, resulting in producing and fixing insoluble and incombustible inorganic matter 5, which is different from the insoluble and incombustible inorganic matter 4, in the wood A.

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 the wood, flame retardance (fire retardance), dimensional stability,
Preservative/insect repellent, mechanical strength. Research and development are being carried out on methods for imparting surface hardness and the like.

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

(al Coating with inorganic substances (bl Promotion of carbonization (C) Inhibition of chain reaction in flaming combustion (d)
Generation of nonflammable gas (e) Heat absorption due to decomposition and release of water of crystallization (f) Insulation by foam layer Here, the modification method of incorporating insoluble nonflammable inorganic substances into wood is as explained below. In addition to a), depending on the type of inorganic material, (b), (C), (d)
This is an excellent method that can also be expected to have effects such as Furthermore, once the insoluble, nonflammable inorganic substance is fixed in the wood structure, there is little risk of it melting out of the wood, so there is little worry that the above-mentioned effects will be diminished.

The mechanism of flame retardancy from (al to +dl) described above will be explained in detail below.

(Coating with an inorganic material such as Al means that even if it is a combustible material, it can be made flame retardant by combining it with a nonflammable inorganic material at an appropriate blending ratio. Wood chip cement board is made by mixing combustible wood with non-combustible cement at a weight ratio of about 3:E to 1:1, shaped into a board, and is recognized as a quasi-noncombustible material by JTS. There is.

(The mechanism that promotes carbonization of BL is as follows. When wood is heated, it thermally decomposes and generates flammable gas, which causes flaming combustion. At this time, phosphoric acid or boron The presence of acid promotes the thermal decomposition, or carbonization, of wood, rapidly forming a char layer. This char 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.

(Inhibition of the chain reaction in flaming combustion of Cl is contributed by halogen. In the radical oxidation reaction in the flame, the halogen acts as a chain transfer agent, and as a result, the oxidation reaction is inhibited. This mechanism produces a flame retardant effect. Therefore, if the insoluble nonflammable inorganic substance contains halogen, the W# flame effect can also be obtained by this mechanism. (The generation of nonflammable gas in dl is caused by the following mechanism. In other words, compounds such as carbonates and ammonium salts generate nonflammable gases such as carbon dioxide, sulfur dioxide, and hydrogen halides through thermal decomposition, and these gases dilute combustible gases, causing combustion. Therefore, if the insoluble nonflammable inorganic substance contains carbonates or other substances that generate nonflammable gases, a flame retardant effect can also be obtained by this mechanism.Next, wood preservatives and Explain about insect control.

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. Insect control is the same as preservative. Therefore, if insoluble, non-combustible inorganic substances are included in the internal 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.

Furthermore, dimensional stabilization and mechanical strengthening of wood will be explained. 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,
It can improve dimensional stability and mechanical strength. 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, only a small percentage of the treatment liquid penetrates into the wood. Only a solvent such as water is left. This is due to the following reasons. That is, the narrowest part of the path through which the treatment liquid passes when penetrating into the wood is the pisotomen plan, where the pore diameter is approximately 0.
1μ, whereas dispersed insoluble, nonflammable inorganic particles typically have a diameter of 0.1μ. This is because it is considerably larger than 1μ1.

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 (in order, ``cation-containing treatment liquid'', ``
Anion-containing treatment solution) is prepared by dissolving a water-soluble inorganic substance in water, and both aqueous solutions are sequentially impregnated into raw wood to react with both ions in the wood. This is a method for producing modified wood that generates inorganic substances (see JP-A No. 61-246003, 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 that has extremely excellent antiseptic and insect repellent properties, dimensional stability, 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 liquid containing C a C1 z and a cation-containing treatment liquid containing C a C1 z and Kyo CO. or impregnating wood with an anion-containing treatment liquid containing
H4). HPO. The wood is impregnated with an anion-containing treatment solution containing anion-containing treatment liquid, thereby producing insoluble and nonflammable inorganic substances in the wood.

[Problem to be solved by the invention] However, in the above-mentioned method, most of the inorganic substances produced are of a single precept, and cannot be applied to cases where multiple characteristics are required.Therefore, improvement in this point is required. was.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a method for producing modified wood that can have multiple characteristics and has even better performance than conventional wood. [Means for Solving the Problems] In order to solve the above problems, the method for producing modified wood according to the present invention involves adding an insoluble, non-combustible inorganic substance to the raw material wood to be modified by mixing it. A method for producing modified wood, in which the insoluble incombustible inorganic substance is generated and fixed in the wood tissue by impregnating one of the combinations of a cation-containing treatment liquid and an anion-containing treatment liquid and then impregnating the other. After the insoluble nonflammable inorganic substances are generated and fixed in the wood tissue, the insoluble nonflammable inorganic substances are mixed with anionic species and/or cationic species remaining in the wood without participating in the inorganic substance production reaction. It is characterized in that it is further impregnated with another cation-containing processing liquid and/or an anion-containing processing liquid to generate and fix an insoluble non-flammable inorganic substance different from the above-mentioned insoluble non-flammable inorganic substance. 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 incombustible inorganic substances (insoluble biobottoms) 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, fufluoride salts, bromide salts, and hydroxide salts. Among these salts, a specific example of carbonate is B a C O *
, C a COs , FeC○1 , M g CO
s, MnC01, NfC○s, ZnC
O* etc. Two or more of these may coexist in the wood. Insoluble and nonflammable inorganic substances in wood are
It 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.

The cation portion of the insoluble, nonflammable inorganic substance includes, for example, alkali metals such as Na and K, carbon
Al such as a, Ba, Mg, Sr? Lithium metal, Mn,
Transition elements such as Ni and Cd, carbon group elements such as Si and Pb,
Zn, A/, etc. are mentioned. Among these, alkali metals, super-alkali metals, Zn and Al are preferred.

Examples of the anion moiety of the insoluble nonflammable inorganic substance include B401, B○, P○4, CO
(2), SO4, NO, ○HXCl, BrSF, (2), and OH. Among these, Bow, P.
O4, Co. , So4 and OH anions are preferred. Furthermore, among the anions, B4 0t , BOs
and P○4 is the effect due to the mechanism of bl, C
O, is the effect due to the mechanism of (di, C I S
Halogens such as F and B r are used in the above (C) and (d
) effects can be expected from each mechanism.

Note that Cl, F, and Br have excellent flame retardant effects, but
Care must be taken when using it as it generates a large amount of smoke.

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 a desired cation and an anion-containing treatment liquid containing a desired anion are prepared. However, not all combinations of cations and anions are possible, so it is preferable to select an appropriate combination that can be used, taking into consideration constraints such as the ionic radius.

Examples of inorganic substances that dissolve in water to produce the desired cation include MgCl. , MgBrz, MgSOa・
Hz OSMg (Not)t' 6H! O.S.C.
aClz, CaBrx, Ca(NOx)z,
BaCl・2Hx OSBaBr*, Ba (No
w)z, Alc1m, AIBr*, A1t(So
n) x % Al (Noses-' 9Ht OSZ
Examples include, but are not limited to, nCl, etc. However, drugs other than halides have low solubility and are difficult to obtain at the required concentration.
It is preferable because it has high solubility and it is easy to obtain the required concentration. Examples of inorganic substances that dissolve in water to produce the desired anion include Nag Cot, (NH.)I C
O. , Hz S○4, Nag SO4, (NH4)l
SO4 , Ht POa , Nag HP○4, (N
H4)! HPO4, Ht Box, Na BO!
, N.H. Box, etc., but is not limited to these. 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 that a uniform aqueous solution can be formed without reacting with each other.

An example of the impregnation treatment according to the present invention will be explained in detail with reference to FIG.

First, as shown in the same figure (al), raw wood A is immersed in cation-containing treatment liquid 1 (first liquid) to impregnate the first cation 11 and first anion 12 into the wood A.Next As shown in Figure tb), the first ion 11.1
2 was impregnated with anion-containing treatment liquid 2 (second
When the second cation 21 and the second anion 22 are impregnated into the wood A by immersing the wood A in 22, and an insoluble, nonflammable inorganic substance 4 is generated and fixed in the wood A.

At this time, the first anion 12 and the second cation 21 that do not participate in the production reaction of the insoluble nonflammable inorganic substance 4 remain in the wood A. Next, as shown in the same figure (dl),
The wood A subjected to the above treatment is immersed in another cation-containing treatment liquid 3 (third m) containing a third cation 31 that reacts with the residual anion 12 to produce another new insoluble, nonflammable inorganic substance. When the third cation 31 is impregnated into the wood A, the first anion l2 remaining from the beginning is
This third cation 3l reacts with the wood A to form a
An insoluble nonflammable inorganic substance 5 different from the insoluble nonflammable inorganic substance 4 is generated and fixed. Note that, since the above-mentioned another cation-containing treatment liquid 3 also contains the third anion 32, this is also impregnated into the wood A, but it does not participate in the above reaction.

In the above-mentioned impregnating treatment, if necessary, a fourth liquid, a fifth liquid, a sixth liquid, etc. may be prepared and impregnated repeatedly to make the product layer denser. good. The cation/anion-containing treatment liquids used at this time may be of the same type or different types, and their concentrations are not particularly limited. The impregnation treatment method for each liquid, the impregnation treatment time, etc. are not particularly limited, and impregnation can be carried out under reduced pressure or by coating.

Note that, prior to the impregnation treatment with the first liquid, the raw material wood may be subjected to a water saturation treatment so that the wood is sufficiently saturated with water. This is because the cations in the treatment liquid are thereby rapidly diffused using the water in the wood as a medium, and the incorporation time can be shortened. This water saturation treatment method is not particularly limited, but may be carried out by submerged wood storage, steaming, impregnation under reduced pressure, or impregnation under pressure.

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

After the above-mentioned trench treatment has produced and fixed the non-meltable and non-combustible inorganic substances in the wood, if necessary, the surface of the wood is washed with water, etc. Dry to obtain modified wood.

In addition, in order to increase the durability and weather resistance of the wood, and also to reduce the amount of residual halogen, leaching treatment is performed as necessary to remove any soluble unreacted material remaining in the wood. Ions, by-products, etc. may also be removed. The above-mentioned soluble components left in the wood absorb a large amount of water and moisture, and depending on the type, they may exhibit deliquescent properties, so if too large amounts of these remain, the water and moisture absorption of the wood will increase. It's too much. If this happens, there is a risk that the wood would be inappropriate for use as a building material, so these are removed through leaching treatment to improve the water resistance and weather resistance of the wood. The above-mentioned washing with water and the like is also performed for the same reason to remove compounds generated on the surface layer of the wood.

This leaching treatment is performed by providing a post-treatment bath and immersing the material in water for a long time, or leaving it in running water for washing.

By the way, some of the fusible components are nonflammable,
Of wood! Since there are components that can contribute not only to i-burning but also to improving mechanical strength and dimensional stability, it is a good idea to leave some of these components as appropriate and improve wood performance by that amount.

Next, regarding the appearance of modified wood, that is, its wood texture, when it dries after treatment, the insoluble compounds produced precipitate on the wood surface, making the entire wood look white and powdery, impairing its appearance. Therefore, it is effective to wash the wood after drying to maintain its appearance.

The ratio of the amount of bath used for the water saturation treatment, impregnation treatment, demelting treatment, etc. to the amount of wood is not particularly limited, but for example, the amount of bath may be about 10 times the weight of the untreated wood. Ru.

Although the explanation has been given so far based on an example in which three liquids are impregnated in the order of a cation-containing treatment liquid, an anion-containing treatment liquid, and another cation-containing treatment liquid, the order of the manufacturing method according to the present invention is not limited to this. Needless to say.

[For production]

In the method for producing modified wood according to the present invention, after producing and fixing an insoluble incombustible inorganic substance inside the wood, it is mixed with cations and/or anions that remain in the wood without participating in the production reaction of this inorganic substance. By further impregnating another anion-containing treatment liquid and/or a cation-containing treatment liquid that generates an insoluble nonflammable inorganic substance, an insoluble nonflammable inorganic substance different from the above-mentioned insoluble nonflammable inorganic substance is generated. For this reason, different types of insoluble and nonflammable inorganic substances are fixed inside the wood, so that each inorganic substance exhibits its characteristics, has a synergistic effect, and compensates for each other's shortcomings. 1 insoluble nonflammable inorganic substance
It is possible to obtain modified wood that has better flame retardancy, antiseptic/insect repellent properties, dimensional stability, hardness, etc. than modified wood produced and fixed only by different types, and which does not deteriorate in these properties. In addition, the obtained modified wood has an inorganic substance 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.

〔Example〕

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

Example 1 A 2cm thick sliced veneer of Douglas fir wood was decompressed to 301 mHg or less and held for 1 hour, then water was poured in, and when the wood was completely immersed in water, it was released to normal pressure and left at room temperature for 24 hours. Leave it for a while to saturate it with water.

The obtained water-saturated veneer was mixed with 2.011101/1 water in the first bath.
l of B a C l *aqueous solution, 0.4 mol of second bath
/ 1 g of A 1 g (S O4)s aqueous solution in 1 liter of water.
The wood was immersed for several hours to impregnate the wood and create and fix barium sulfate in the wood. Next, add this wood to the third bath.
．． The wood was immersed in a 2 mol/1 water NHs aqueous solution for 24 hours to produce and fix aluminum hydroxide in the wood. As a post-treatment to remove water-eluted slag, the wood was left in water for 24 hours. The surface of the wood was thoroughly washed with water and then dried to obtain modified wood.

Note that the temperature of the aqueous solution used in the above immersion treatment was 60°C.

Example 2 In Example 1, as the third bath, 0. 1 mol/
Modified wood was obtained in the same manner as in Example 1 except that 1 liter of water was used as an aqueous NaOH solution.

Comparative Example 1 - Modified wood was obtained in the same manner as in Example 1 except that the immersion treatment in the third bath was omitted.
2 and Comparative Example 1, the impregnation rate of insoluble and noncombustible inorganic substances, flame retardance (fire retardancy), dimensional stability, antiseptic/insect repellent properties, and hardness were investigated. The impregnation rate of the inorganic substance is the weight ratio of the infusible and nonflammable inorganic substance to the weight of bone-dry wood. Flame retardancy (fire resistance) is J
Flame retardant class ■ in IS standard A1321 is ◎, flame retardant ■ class is △, and intermediate performance is ○. Dimensional stability was evaluated by the improvement rate of dimensional change when saturated with water, and the case of untreated wood was set as 0%, and the case of no dimensional change was set as 100%. Preservative and insect repellent properties were evaluated based on the rate of decrease in wood weight in response to decay and insect damage, with ◎ indicating almost no decrease, × indicating the same level as normal untreated wood, and ○ indicating an intermediate level.

Hardness is evaluated using a value corresponding to the force required to penetrate a needle to a certain depth in the area between the grains, with ◎ being harder than that of oak wood, and × being the hardness of normal bay mat wood. , and cases in between are indicated as ○.

The above results are shown in Table 1.

As shown in Table 1, the modified wood obtained by impregnating the wood with another anion-containing treatment solution as the third bath to produce or fix two types of insoluble and nonflammable inorganic substances is: Compared to modified wood in which only one type of insoluble, noncombustible inorganic substance is formed and fixed in the wood, it has superior flame retardancy (fire retardancy), dimensional stability, antiseptic and insect repellent properties, and hardness. I know that there is.

〔Effect of the invention〕

According to the method for producing modified wood according to the present invention, in order to generate and fix an insoluble nonflammable inorganic substance inside the wood, once the insoluble nonflammable inorganic substance is generated and fixed inside the wood, the generation reaction of this inorganic substance is performed. Further impregnation with another anion-containing treatment liquid and/or a cation-containing treatment liquid which produces an insoluble non-flammable mineral by mixing with the cations and/or anions remaining in the wood without involving the insoluble non-flammable minerals Since insoluble nonflammable inorganic substances different from inorganic substances are generated and fixed, multiple types of insoluble nonflammable inorganic substances can be generated and fixed inside the wood, and only one type of insoluble nonflammable inorganic substances can be generated and fixed inside the wood. Compared to modified wood, it has better flame retardancy, rot and insect repellency, dimensional stability,
It is possible to obtain modified wood that has better hardness and other properties and does not deteriorate in these properties. Further, in the present invention, the cation-containing treatment liquid includes at least one selected from the group consisting of alkali metals, alkaline earth metals, A6, and Zn, and the anion-containing treatment liquid includes BO. , P.O. , C
o. , So. Better effects can be obtained by using at least one anion selected from the group consisting of OH and OH anions.

[Brief explanation of drawings]

FIGS. 1(a) to 1(d) are explanatory diagrams schematically showing one embodiment of the method for manufacturing modified wood according to the present invention in the order of steps. A...Wood 1...Cation-containing treatment liquid 11...
・First cation 12...lth anion 2...
・Anion-containing treatment liquid 21...Second cation 2
2...Second anion 3...Another cation-containing treatment liquid 3 l...Third cation 3 2...Third anion 4...Insoluble nonflammable inorganic substance 5...Another Insoluble nonflammable inorganic substance

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 nonflammable inorganic substance is impregnated into the wood tissue and is formed and fixed therein. Further impregnating with another cation-containing treatment liquid and/or anion-containing treatment liquid that produces an insoluble non-flammable inorganic substance by mixing with the anionic species and/or cationic species remaining in the wood without removing the insoluble non-flammable mineral A method for producing modified wood characterized by producing and fixing an insoluble, nonflammable inorganic substance different from inorganic substances. 2. The cation-containing treatment liquid contains at least one selected from the group consisting of alkali metals, alkaline earth metals, Al, and Zn, and the anion-containing treatment liquid contains B.
The method for producing modified wood according to claim 1, which contains at least one anion selected from the group consisting of O_3, PO_4, CO_3, SO_4 and OH anions.