JPH01166904A - Manufacture of improved wood - Google Patents

Abstract

PURPOSE: To efficiently generate an insoluble incombustible inorganic substance to a deep portion of a timber by impregnating the timber with one of a cation- containing treating liquid and an anion-containing treating liquid for generating the substance by mixing, and then impregnating it with the liquid later by a pressure drop. CONSTITUTION: Aqueous soluble inorganic substances containing cation and anion are dissolved in respective waters to prepare a cation-containing treating liquid 2 and an anion-containing treating liquid 4. A timber 1 is dipped in the liquid 2 and impregnated with the cation 3. After the impregnation, the timber 1 containing the cation 3 is dried. Then, the dried timber 1 is dipped in the liquid 4 under a reduced pressure, and impregnated with the anion 5 to generate an insoluble incombustible inorganic substance 6 in the timber. The reduced pressure state is preferably 50 mmHg or less so as to sufficiently, efficiently impregnate the timber with the liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for producing modified wood used as building materials and the like.

[Background technology]

As a method of modifying wood, it is made flame retardant (fire retardant) by producing insoluble, non-combustible inorganic substances in wood.

Methods of imparting dimensional stability, antiseptic/insect repellent properties, mechanical strength, etc. are being researched and 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 (C1 Inhibition of chain reaction in flaming combustion (dl) Generation of nonflammable gas (e) Absorption of heat due to decomposition and release of crystal water (f) Insulation by foam layer The modification method of incorporating an insoluble, nonflammable inorganic substance will be explained below, but in addition to the above (a), it is an excellent method that can also be expected to involve movement by mountains) or d), depending on the type of inorganic substance. It is.

Furthermore, once this insoluble, nonflammable inorganic substance is fixed in the wood structure, there is little possibility that it will be dissolved out of the fabric material thereafter, so there is little concern that its effects will diminish.

In the above, covering with an inorganic substance in (a) means that even if the material is combustible, it is not known that it is non-combustible. It is mixed at a weight ratio of approximately 1:1 and formed into a plate shape, and is recognized as a quasi-noncombustible material by the JIS standard.

The carbonization promotion in (b) is the following mechanism. 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. Four carbonized layers are formed.

This carbonized layer acts as a heat insulating layer and provides a flame retardant effect. Therefore, if the insoluble nonflammable inorganic substance contains a phosphoric acid component or a boric acid component, the flame retardant effect of the 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, this effect can also be obtained.

Finally, the generation of nonflammable gas (d) 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, we will explain the antiseptic and insect repellent effects of wood containing this insoluble, noncombustible inorganic substance. When fungi cause wood to rot, mycelium first invades the inner cavity of the wood.
If foreign matter is present in the wood or in the cavities, the mycelium will be prevented from entering the wood, resulting in the wood becoming rotten. The foreign matter in the wood lumen does not need to be a particularly antiseptic agent (preservative), and may be anything as long as it does not provide nutrients for fungi. Insect repellents are the same as preservatives; if they have a medicinal effect, it's no big deal, and there are also things that are poorly digestible, indigestible, or have a repellent effect on insects. Preferably. Therefore, if an insoluble, noncombustible inorganic substance that satisfies such conditions is included in the internal cavity of wood, it will be effective in preserving wood and preventing insects.

Furthermore, when such inorganic substances are fixed in the inner cavity of wood or in the cell walls of wood, other physical properties of the wood change accordingly. For example, acoustic properties.

This includes the transmission characteristics of electromagnetic waves such as X-rays, but also the mechanical strength including the dimensional stability and hardness of the wood, especially the surface hardness. If you look at wood structurally, it has many conduits, tracheids, etc., and its cross section has a honeycomb-like structure in which the spaces formed by these tubes are supported by cell walls. Therefore, the size of the honeycomb space, the wall thickness, etc. have a very large influence on the dimensional stability and mechanical properties of the wood. Specifically, if wood is swollen with water and some substance can be fixed in the cell walls of the wood 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, particularly hardness, are improved. Here, as the fixing substance, an inorganic substance that is difficult to dissolve in water can be used, so the effect can be obtained by fixing an insoluble, nonflammable inorganic substance in the wood cell wall.

As described above, the method of incorporating insoluble nonflammable inorganic substances is very effective in modifying wood, including flame retardation, 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 0.1 am. The particle size of the insoluble, nonflammable inorganic material that is the dispersed particle is usually 0.
This is because it is considerably larger than 1 μm.

Therefore, the inventors have first developed a method that can solve this problem. That is, two types of aqueous solutions are prepared that separately contain cations and anions that react to produce insoluble, nonflammable inorganic substances when mixed, and both are sequentially impregnated into raw wood to cause both ions to react inside the wood. This is a method for producing modified wood in which insoluble, nonflammable inorganic substances are fixed (Japanese Patent Application No. 6O-089423). In this way, extremely large amounts of insoluble, nonflammable inorganic substances can be efficiently incorporated into the wood, and many improvements have also been made in response to new problems.

For example, when immersion treatment is performed, during the second and subsequent immersion, the components that were previously impregnated into the wood flow out and react not only inside the wood but also outside the wood, that is, in the treatment bath. There was a problem in that insoluble and nonflammable inorganic substances were generated.

Since these contaminate the bath and lead to an increase in the amount of chemicals used, it is important to suppress the generation of these substances outside the wood as much as possible, and to generate a sufficient amount of insoluble, nonflammable inorganic substances only within the wood. is preferred. To this end, so far, efforts have been made to make the concentration of the treatment liquid for later impregnation equal to or higher than the concentration of the treatment liquid for earlier impregnation, or to provide a sufficient impregnation time.

However, even if the treatment is carried out with sufficient impregnation time, the reaction between cations and anions mainly occurs on the surface of the wood, and the formation of insoluble, nonflammable inorganic substances cannot proceed deep into the wood. The problem remains that it is difficult. This phenomenon can be understood as follows. First, in the wood impregnated with the first treatment liquid (temporarily assumed to be a cation-containing treatment liquid), the injected cations exist in a mobile state.

Next, the wood is immersed in a treatment solution containing anions that reacts with the wood, and when anions are present on the wood surface, the internal cations move toward the anions, that is, toward the surface of the wood. Move and go. In this way, the reaction between both ions mainly occurs at the interface where the image processing solution comes into contact, and the insoluble and nonflammable inorganic substances naturally come to be generated on the surface layer of the wood. This insoluble, nonflammable inorganic material then becomes a hindrance, preventing the treatment liquid from entering into the wood and preventing it from reaching deep into the wood. Therefore, in order to overcome such obstacles and generate insoluble, non-combustible inorganic substances deep into the wood, more time is required, which has been problematic in terms of efficiency and the like.

[Purpose of the invention]

In view of the above circumstances, this invention contains a large amount of insoluble and nonflammable inorganic material deep inside, and has flame retardant properties, antiseptic properties, and
Modified wood with excellent insect repellency, two-dimensional stability and hardness,
The purpose is to provide a method for manufacturing efficiently in a short time.

[Disclosure of the invention]

In order to achieve the above object, the present invention impregnates raw material wood to be modified with one of a combination of a cation-containing treatment liquid and an anion-containing treatment liquid that produce insoluble, non-flammable inorganic substances when mixed. A method for producing modified wood in which the inorganic substance is generated and fixed in the wood structure by impregnating the other material afterwards, the method comprising impregnating the treated liquid under reduced pressure with the treatment liquid to be impregnated later. The main points of this paper are the manufacturing methods of modified wood.

The present invention will be explained in detail below.

The raw material wood for modification used in this invention is not particularly limited, and examples include raw wood logs, sawn timber products, sliced veneer 2 plywood, and the like. There are no limitations on these 4M types either.

Insoluble, nonflammable inorganic substances that are generated in wood and dispersed and fixed in the wood tissue are not particularly limited, and include, for example, borates, phosphates, hydrogen phosphates, carbonates, sulfates, and hydrogen sulfate. salts, silicates, nitrates, fluorides,
Examples include bromides, hydroxides, etc., and two or more types of inorganic substances may coexist in the wood.

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

Elements constituting the cation portion of the above-mentioned inorganic compounds (salts) include alkali metal elements such as Na and Mg.
Although it is preferable to use alkaline earth metal elements such as , Ca, Sr, and Ba, Zn, and AI, the use is not limited to these. For example, transition elements such as Mn, Ni, and Cd, and transition elements such as St and Pb are used. Carbon group elements etc. may also be used.

BO constitutes the anion portion.

, PO4, Cot, SO4 and OH anions are preferably used. For Bon and po4 anions, the effect of the flame retardant mechanism (b) can be obtained, and for CO and anions, the effect of the same mechanism (d) can be obtained, so that the − layer is preferable. However, it is not limited to these, for example, F, CI, Br, O.

It may be N Ox , S i 04 , 310g anion, or the like. In particular, for halogens, the same (C)
There is an advantage that the effects of (d) and (d) can be expected together.

The cation portion and the anion portion may be used alone or in combination, but not all combinations are possible, and the ionic radius, etc. There are restrictions due to In view of such conditions, both are arbitrarily selected and the water-soluble inorganic substances containing them are respectively dissolved in water to prepare the cation-containing treatment liquid and the anion-containing treatment liquid.

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

Inorganic substances that dissolve in water to produce the above cations include MgClx, MgBrz, MgSO4・Hz
O, Mg (NOx)z 76Hx O, CaC1g
, CaBrx , Ca (Not)z , BaC1z
” 2 Hz O+ B a B r z + B
a (N 0n)z , A ICl s r A I
B r * + ' Al t (S 04 )
s + A I (Not),” 9H! O, ZnC1
, etc. may be mentioned as an example, but the invention is not limited to these. Inorganic substances that dissolve in water to produce the above anions include Nag Cot, (NH4)
2 COx, Hz SO4, Nag SO4, (NH
4) tSOa, Hs PO4, Nag H
PO4, (NH4)z HPOa, HI Bo
Examples include, but are not limited to, x, Na Bow, NHaBO, and the like. An example of the impregnation treatment according to the present invention using such a cation/anion-containing image processing solution will be explained with reference to the drawings. First, as shown in FIG. 1, a wood 1 is immersed in a cation-containing treatment liquid 2 to impregnate the wood 1 with cations 3. At this time, prior to impregnation, the raw material wood may be subjected to water saturation treatment so that the wood is sufficiently saturated with water. This is because the cations in the treatment liquid will diffuse quickly using the water in the wood as a medium, and the impregnation time can be shortened. Here, the above-mentioned water saturation treatment methods include underwater wood storage, steaming, impregnation under reduced pressure,
Examples include impregnation under pressure, and are not particularly limited.

After the impregnation treatment, the wood 1 containing the cations 3 is taken out of the bath and dried, as shown in FIG. 2, in preparation for the next vacuum impregnation. In vacuum impregnation, the voids inside the wood are depressurized and the treatment liquid is injected into the low-pressure areas, so it is better to have voids in the wood that can create a low pressure. This is because it is better if it is dry. This drying method is not particularly limited, and the degree of drying does not need to be completely dry, as long as it is dried to a level below the fiber saturated moisture content (about 30%).

Next, the dried wood 1 is immersed in the anion-containing treatment liquid 4 under reduced pressure, as shown in FIG. An insoluble, nonflammable inorganic substance 6 is produced. This reduced pressure impregnation is performed, for example, by the following operation. First, the raw material wood is fixed in a vacuum container (not shown) and the pressure is reduced, and once the pressure has been reduced to a predetermined pressure, the above pressure is maintained for 1 to 2 hours to reduce the pressure inside the wood, and then the wood is placed in the container. The treatment solution is introduced, and once the wood is completely immersed in the solution, the pressure is returned to normal. Alternatively, the treatment liquid is first introduced into the container and the wood is immersed in it, then the pressure is reduced from that state, and when the predetermined pressure is obtained, it is held for about 1 to 2 hours, and then it is released to atmospheric pressure. Good too. The reduced pressure state is not particularly limited, but is preferably 59 mmHg or less in order to efficiently perform sufficient impregnation.

This reduced-pressure injection allows the treatment liquid to reach the inside of the wood, but if you want to impregnate a larger amount and deeper into a thick plate, etc., you can apply pressure after applying the reduced-pressure injection. The pressure may be repeated.

After the above-described reduced-pressure impregnation operation, the wood is kept immersed in the treatment liquid for several hours, and it is recommended that the treatment liquid be heated at this time. This heating is effective in uniformly dispersing the treatment liquid and promoting the reaction for producing insoluble and nonflammable inorganic substances. That is, during the drying process, the initially impregnated cations solidify from a liquid state called ions to a solid component. Next, an anion treatment liquid is quickly injected, but at this time, both ions do not immediately start reacting, but first undergo a dissolution process in which the solid components are dissolved. Then, in the ionic state, both ions come into contact and a reaction occurs.

Here, the fact that the cations are in a solid state within the wood is one of the factors that allows this invention to produce the insoluble, nonflammable inorganic substance deep within the wood in a short period of time. Normally, it is in a state where it can react immediately inside the wood,
In other words, since it exists in an ionic state, inorganic matter formation begins at the same time as anions enter, and as mentioned above, this occurs in the surface layer of the wood, making it difficult for anions to penetrate into the interior, and forming the surface layer. The unreacted cations are trapped in the insoluble, nonflammable inorganic substances produced during the process, and are left deep inside the wood.

However, if the cations inside the wood are in a state where they cannot easily react, that is, in a solid state, the anions can be quickly and sufficiently distributed deep into the wood by vacuum impregnation, before insoluble and nonflammable inorganic substances are formed on the surface layer. after that,
By heating the material in the immersed state to accelerate the reaction, a large amount of insoluble and nonflammable inorganic material 6 can be produced, as shown in FIG.

After that, leaching treatment is performed as necessary to remove soluble unreacted ions and by-products, washing with water, etc.
Insoluble and nonflammable inorganic substances generated on the surface layer of the wood may be removed. The above-mentioned soluble components left in the wood absorb a lot of water and moisture, and depending on the type, they may exhibit deliquescent properties, so if too much of these components remain, the water absorption and hygroscopicity of the wood will increase. It's too much. This may make the wood unsuitable for use as a building material, so these can be removed through leaching treatment to improve the water resistance and weather resistance of the wood.

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

Regarding the appearance of modified wood, that is, its wood texture, when it is dried after treatment, the insoluble and nonflammable inorganic substances generated on the surface of the wood precipitate and the entire wood becomes white, as if it had been dusted with powder. Since there is a risk that the wood will get dirty and the appearance will be damaged, it is also effective to wash the treated wood to maintain its appearance.

Although the explanation has been given so far based on an example in which two liquids are impregnated in the order of cation and anion, it goes without saying that the manufacturing method according to the present invention is not limited to this. For example, anion and cation may be impregnated in this order, and the impregnation is not limited to two liquids, but also a third bath, a fourth bath, etc.
etc. may be provided and impregnated repeatedly. The impregnation treatment method at this time is not particularly limited, and the cation- and anion-containing image processing solutions may be of the same kind or different kinds. Further, the treatment liquid to be first impregnated may also be injected by vacuum impregnation, and in this case, the water saturation treatment as a pretreatment is omitted.

Next, Examples and Comparative Examples of the present invention will be described.

■ Yeongmulin Rit Seitai (Example 1) A 2W thick sliced veneer of Douglas fir was fixed in a vacuum container, and the pressure was reduced to 10wHg or less using a rotary pump and held for 1 hour, then water was poured in to ensure that the wood was completely covered. Once submerged in water, the leak valve was opened to release the pressure to normal pressure, and the sample was left at room temperature for 24 hours to saturate with water.

The obtained saturated veneer was immersed for 24 hours in a barium chloride aqueous solution (2 mol/j) heated to 80°C, then the wood surface was washed with water, and dried at 60°C for 24 hours in a hot air dryer. I did it.

Next, the wood, which was reduced in pressure to 10 waHg or less in the same manner as above, was treated with diammonium hydrogen phosphate (4 mol/It).
and orthoboric acid (6 mol/j!) mixed aqueous solution, returned to normal pressure and left at 80° C. for 24 hours.

After the impregnation treatment, the veneer was sufficiently washed with water and then dried to obtain a modified wood.

(Examples 2 to 9) In the same manner as in Example 1, veneers were treated under the conditions shown in Table 1 to produce each modified wood. However, in Example 7, a 15 crane thick sword veneer made of Douglas fir was used. Further, in Example 9, a third bath was also provided and the immersion impregnation treatment was performed at normal pressure.

(Comparative Examples 1 and 2) In the second bath, impregnation under reduced pressure was not performed, but normal pressure immersion was performed in the same manner as in the first bath. The veneers were treated to produce each modified wood.

■ Ei! 7. Regarding the obtained modified wood, the impregnation rate of insoluble and noncombustible inorganic substances, flame retardancy (fire retardancy), dimensional stability, rot and insect repellency, and hardness were improved. The impregnation rate of the inorganic substance is the ratio of the weight of the insoluble incombustible inorganic substance to the weight of bone dry wood. Regarding the flame retardancy, flame retardant class ■ in JIS standard A1321 is ◎, flame retardant ■ class is Δ, and intermediate performance is O. Dimensional stability was evaluated by the improvement rate of dimensional change when saturated with water, and the case of untreated wood with θ%1 dimensional change was defined as 100%. Preservative and insect repellent properties are evaluated by the rate of decrease in wood weight in response to decay and insect damage. ◎9 means that the weight of the wood does not decrease due to decay and insect damage. did.

Hardness is evaluated using a value corresponding to the force required to insert a needle to a certain depth in the area between the grains of the wood, and the hardness is equal to or higher than that of oak wood. ◎ 1 The hardness of normal Douglas fir wood is × , and cases in between were marked as ○.

The above results are shown in Table 1.

As shown in Table 1, the modified wood of the example that was impregnated under reduced pressure in the second bath efficiently contained a large amount of insoluble and nonflammable inorganic substances even with a shorter soaking time than that of the comparative example. It was found that these layers penetrate deep into the wood, giving them excellent performance. Furthermore, in addition to the performance listed in the table, sound insulation performance is improved, and
It has become clear that since heavy metal elements such as Ba are contained, the transmittance of ionizing radiation such as X-rays is also significantly reduced. Furthermore, although Example 7 is an example in which a thick plate was treated, this reduced pressure impregnation method is also suitable for modifying thick plate materials.

〔Effect of the invention〕

The method for producing modified wood according to the present invention is as described above, and in order to generate and fix insoluble incombustible inorganic substances inside the wood, the treatment liquid to be impregnated later is impregnated under reduced pressure, so that it reaches deep into the wood. Can efficiently generate insoluble and nonflammable inorganic substances, and has flame retardant, antiseptic and insect repellent properties 2
Dimensional stability.

Modified wood with excellent hardness etc. can be obtained.

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams of one embodiment of the method for producing modified wood according to the present invention. ■...Wood 2...Cation-containing treatment liquid 4...
Anion-containing treatment liquid 6...Insoluble nonflammable inorganic agent Patent attorney Takehiko Matsumoto Figure 1, Figure 3, Figure 2, Figure 4

Claims (2)

[Claims] (1) The raw material wood to be modified is impregnated with one of the combinations of a cation-containing treatment liquid and an anion-containing treatment liquid that produce insoluble, nonflammable inorganic substances by mixing, and then impregnated with the other. A method for producing modified wood in which the inorganic substance is generated and fixed in the wood structure, characterized in that the treatment liquid to be impregnated later is impregnated under reduced pressure. . (2) A solution in which the cation-containing treatment solution that produces an insoluble nonflammable inorganic substance when mixed contains at least one cation selected from the group consisting of alkali metals, alkaline earth metals, zinc, and aluminum cations. and
And, the anion-containing treatment liquid contains BO_2, PO_4, C
The method for producing modified wood according to claim 1, which is a solution containing at least one anion selected from the group consisting of O_2, SO_4 and OH anions.