JPH02307703A - Manufacture of modified wood - Google Patents

Abstract

PURPOSE:To manufacture modified wood, which is excellent in flame retardancy, dimensional stability, rotproofing and mothproofing properties, mechanical strength and the like and the surface hardness of which is high by producing and fixing a large amount of insoluble and incombustible inorganic material on the surface of the wood by a method wherein impregnation treatment by coating is performed to wood as stock for modification. CONSTITUTION:Cation and anion are arbitrarily selected in response to the composition of the desired insoluble and incombustible inorganic material. By independently dissolving water soluble inorganic materials containing the above- mentioned respective ions in water, anion-containing processed liquid, which contains the desired cation, and anion-containing processed liquid, which contains the desired anion, are prepared. By successively impregnating the above- mentioned cation/anion containing processed liquids, the modified wood con cerned is obtained. In addition, in order to enhance the durability and weatherability of wood, solvent extraction treatment may well be performed, when necessary, so as to remove soluble un-reacted ion or byproduct and the like left in the wood.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing improved water conservancy used as building materials and the like.

(Prior art) As a method for modifying wood, there is a method that imparts flammability (fire retardancy), dimensional stability, rot/insect repellency, mechanical strength, etc. by producing insoluble and nonflammable inorganic substances in wood. the study,
being 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) Acceleration of carbonization (C) Synopsis of chain reaction caused by flaming combustion (d)
Generation of nonflammable gas (e) Heat absorption due to decomposition and release of crystallized water (f) Insulation by foam layer Here, the modification method of incorporating insoluble nonflammable inorganic substances into wood is as described below (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 Moreover, once this insoluble, nonflammable inorganic substance is fixed in the wood structure, there is little possibility that it will be dissolved from the wood thereafter, so there is little worry that its effects will diminish.

In the above, (a) coating with an inorganic substance means that even if the material is flammable, it can be made flame retardant by combining it with a non-flammable inorganic substance at an appropriate blending ratio. For example, the conventionally known wood chip cement board is made by mixing combustible wood with combustible cement at a polymerization ratio of approximately 1+=1 and forming it into a board shape, which is a quasi-noncombustible material according to JIS. It is recognized as.

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 and combustion, but if phosphoric acid or boric acid is present at this time, the thermal decomposition, or carbonization, of the wood is promoted, and the wood quickly burns. A carbonized layer is formed on the surface. 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 the modified wood is even higher. Become something.

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 The mechanism is that the flame retardant effect is produced by inhibiting the Therefore, if the insoluble nonflammable inorganic substance contains a halogen, these effects 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 chloride through thermal decomposition, but these gases dilute flammable gases and prevent combustion. , is the effect. Therefore, if the insoluble nonflammable inorganic substance contains carbonate or other substance capable of generating nonflammable gases, a flame retardant effect due to this mechanism can also be obtained.

Next, wood containing this insoluble, nonflammable inorganic substance + 4 preservatives
Explain the insect repellent effect. When fungi cause wood to rot, hyphae first invade the inner cavity of the wood, but if foreign matter is present in the lumen of the wood, this prevents the mycelium from entering, and as a result, the wood becomes less likely to rot. . 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 the mycelium. The same applies to insect prevention as to preservatives. However, as long as the foreign substance has a medicinal effect, it is acceptable; for example, it is preferable to use a substance that is poorly digestible or indigestible to insects, or a substance that has a repellent effect. 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.

Furthermore, regarding the dimensional stability and mechanical strength of wood, for example, if wood +1 is swollen with water and some substance can be fixed in the wood +4 cell wall in that state, both of the above properties will improve due to the bulk effect. . In other words, if the lumen of the water cells is occupied by the filler, the wood itself becomes less likely to expand or contract, and at the same time, various mechanical strengths, particularly hardness, are improved. Here, as the immobilizing substance, an inorganic substance that is difficult to dissolve in water can be used, so such an effect can be obtained by fixing an insoluble incombustible inorganic substance in the wood cell wall.

As described above, the method of incorporating insoluble nonflammable inorganic substances is a very effective method for modifying wood including flame retardation, but it still 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 pintomen run, and the pore diameter here is approximately 0.1 μm. The diameter of the insoluble nonflammable inorganic particles is usually 0.1μ.
This is because it is much larger than m.

Therefore, the inventors have first developed a method that can solve this problem. That is, two types of aqueous solutions (a cation-containing treatment liquid and an anion-containing treatment liquid) separately containing cations and anions that react to produce insoluble nonflammable inorganic substances when mixed are prepared, and both are sequentially added to raw water. Impregnated with +4 and reacted with both ions inside the wood with -1,
This is a method for producing modified rice +3 that fixes insoluble and nonflammable inorganic substances. (Japanese Unexamined Patent Publication No. 61-246003). In this way, extremely large amounts of insoluble, nonflammable inorganic substances can be efficiently incorporated into the wood.

(A!l! Problem to be solved by the invention) However, it has been found that there is still room for improvement in the hardness of the modified water supply obtained as described above.

In view of these circumstances, the present invention has excellent flame retardancy, dimensional stability, antiseptic properties, insect repellency, mechanical properties, strength, etc.
The purpose is not to provide a method for producing modified rice +1 with high surface hardness.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides two or more types of water-soluble inorganic substances that produce insoluble, non-combustible inorganic substances by mixing the raw material wood to be modified. This is a method for producing modified wood in which an insoluble, nonflammable inorganic substance is generated and fixed in the wood tissue by impregnating each one with an aqueous solution, and the impregnation treatment is performed by coating.

(Function) By performing impregnation treatment by coating, it becomes possible to generate and fix a large amount of non-cooling, non-combustible inorganic substances on the surface of the wood, increasing the surface hardness. In addition, in the treatment by coating, insoluble and nonflammable inorganic substances can be produced intensively on the surface of the water supply, so there is almost no decrease in the impact resistance of the wood itself. Furthermore, it also has the advantage that it is possible to partially impregnate it.

(Example) Next, examples of the present invention will be described.

It should be noted that the embodiments are merely illustrative, and it goes without saying that various changes and improvements may be made without departing from the spirit of the present invention.

The raw material wood for modification used in this invention is not particularly limited, and examples thereof include raw logs, sawn timber products, sliced veneers, plywood, and the like. There are no limitations on these tree species either.

Insoluble, nonflammable inorganic substances that are generated in wood and dispersed and fixed in the wood tissue include, but are not particularly limited to, borates, phosphates, hydrogen phosphates, carbonates, sulfates, and hydrogen sulfates, Examples include silicates, sulfates, hydrides, 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, preferable examples of the elements of the cation moiety constituting the insoluble nonflammable inorganic substance include alkali metals such as Na and K, alkaline earth metals such as M, Ca, Sr, and Ba, Zn, and AI. Examples include transition elements such as Mn, Ni, and Cd, and Si.

It may be a carbon group element such as pb, and is not particularly limited.

As the anion constituting the insoluble nonflammable inorganic substance, BO
3, PO4, CO3, SO4 and 0II7 ion,
Shown as a good example. The IIO,1,PO4 anion is more suitable because it provides the effect due to the flame retardant mechanism described above, and the CO3 anion provides the same effect.

However, it is not limited to these, and for example, F.
, CI, br, O, NO3, 5io3 anions, etc. may be used.

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 An anion-containing treatment liquid containing cations and an anion-containing treatment liquid containing a desired anion are prepared.

In addition, the above-mentioned 011 anion etc. may be used alone, or
They may be contained together in a cation-containing treatment liquid and/or an anion-containing treatment liquid containing other anions, and may be coated eight times to produce abatite or the like in the wood.

Inorganic substances that dissolve in water to form the desired cation include MgCl2 + MgBrz l MgSO4
・HzO+Mg(NO3)z ・61120, Ca
Cl2, CaBr2, Ca(NO3)z +B
aC1z ・2+120 + BaBr2 1
Ba(NO3)z, 8IcI□.

AIBrz + 812 (SO4)3, 81
(NO3)3, 9+120, ZnCI.

etc. may be mentioned as an example, but the invention is not limited to these. As an inorganic substance that produces the above desired anion when dissolved in water with IJ, NazCO31 (NtlJ2CO3゜+t2s04.NazSO4+ (NI+4)2)
SO4, H3PO4, Na, 1IPO4゜(NH4)Z
IIPO4, +131 (03, NaBO2, Nll4B
02 etc. are given as an example, but the invention is 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.

Wood is treated by sequentially impregnating it with the above cation/anion-containing treatment solutions, but in the present invention, the order of treatment is not particularly limited.

Furthermore, the cation/anion-containing treatment liquids may be of the same type or different types.

The above is the impregnation treatment operation, and then, if necessary, the surface of the wood is washed with water and dried to obtain a modified wood. In addition, in order to improve the durability 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. These soluble components absorb a large amount of water and moisture, and depending on the type, may exhibit deliquescent properties, so if they are present in excessive amounts in wood, the water absorption and moisture absorption of the wood will become too high, making it difficult to use for building materials, etc. This is because there is a risk that it may become inappropriate. On the other hand, these soluble components also contain many components that are nonflammable and can contribute not only to the M fuel ratio of wood but also to mechanical strengthening and dimensional stability, so it is important to leave them as appropriate. One way to do this is to improve the performance of the wood accordingly. Further, if necessary, curing may be performed after the impregnation treatment to promote the reaction for producing insoluble and nonflammable inorganic substances.

Next, more detailed examples of the present invention will be described together with comparative examples.

(Example 1) BaCIz 2 mol/water II on a 3 nm thick Douglas fir veneer! .

water) solution at 30 g/R2, followed by (N114
)2HP0.3.5mol/water1! 30g/R2 of aqueous solution
After coating, washing with water and drying, a modified wood was obtained.

(Examples 2 to 5) Impregnation treatment was performed in the same manner as in the above examples under the conditions shown in Table 1 to obtain modified wood.

(Comparative Example 1.2) Comparative Example 1 was an untreated material, and Comparative Example 2 was impregnated with the first liquid under reduced pressure and then immersed in the second liquid.

The impregnation rate of insoluble and noncombustible inorganic substances and surface hardness of the obtained modified wood were investigated.

The following results are shown in Table 1.

As shown in Table 1, the modified wood that has been impregnated by coating produces insoluble and non-combustible substances intensively on the wood surface with a simpler treatment than the comparative example, achieving a high degree of surface hardness. has been done.

(Effects of the Invention) In the present invention, the raw material wood to be modified is individually impregnated with two or more aqueous solutions of water-soluble inorganic substances that produce insoluble incombustible inorganic substances when mixed.
In a method for producing modified wood in which the same insoluble nonflammable inorganic substance is generated and fixed in the Mi weave, the insoluble nonflammable inorganic substance is selectively, uniformly, and densely generated in the surface layer of the wood by performing the impregnation treatment by coating. Therefore, the surface hardness of modified wood can be improved. Furthermore, since the treatment is simple, the treatment efficiency is improved.''-1 It also has the advantage that partial impregnation treatment is possible.

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Claims (1)

[Claims] A modification method in which the 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, and the same insoluble non-flammable inorganic substances are generated and fixed in the wood structure. In the manufacturing method of quality wood,
A method for producing modified wood, characterized in that the impregnation treatment is performed by coating.