JPS62249707A - Improved wood - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to modified wood used for building materials and the like.

[Background technology]

In order to impart flame retardancy, antiseptic/insect repellent properties, and dimensional stability to wood, methods have been developed in which wood contains insoluble and noncombustible inorganic substances.

Next, flame retardant wood will be explained.

There are various treatment methods for imparting flame retardancy to wood. When classified based on the flame retardant mechanism, they can be divided into the following types.

(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 crystallized water (fl) If a water-insoluble nonflammable inorganic substance is included in the insulation wood using a foam layer, in addition to the above (a), types of insoluble nonflammable inorganic substances In some cases, effects due to mechanisms such as (bl and (C)) can also be expected.

Regarding the mechanisms of (a), (b) and (C),
This will be explained in detail next. The inorganic coating in (a) is
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 noncombustible cement at a weight ratio of about 1:1 and forming it into a board shape, which is recognized as a quasi-noncombustible material by JIS. It is being The mechanism of the carbonization promotion reaction (b) is as follows. When wood is heated, it thermally decomposes and generates flammable gas, which ignites and burns, and the presence of phosphoric acid or boric acid promotes the thermal decomposition, or carbonization, of the wood. The carbonized layer thus formed acts as a heat insulating layer and has a flame retardant effect. Therefore, if the insoluble nonflammable inorganic substance contains a phosphoric acid component or a boric acid component, a flame retardant effect can be obtained by this mechanism. (C) is a mechanism in which halogen acts as a chain transfer agent in a radical oxidation reaction in a flame, thereby inhibiting the oxidation reaction and producing a flame retardant effect. Therefore, if the insoluble nonflammable inorganic substance contains a halogen, a flame retardant effect can be obtained by this mechanism. If it is insoluble, there is little risk of elution coming out of the wood.

Next, we will explain how to prevent wood from rotting and insects.When fungi cause wood to rot, it is essential that mycelia first invade the inner cavity of the wood. However, if foreign matter is present in the internal cavity of the wood, mycelium cannot enter, and as a result, the wood becomes less susceptible to decay. The foreign matter in the internal cavity of the wood does not need to be a drug with a particular antiseptic effect, and may be anything as long as it does not serve as nutrients for fungi. The same applies to insect repellent as preservative. Therefore, if unnecessary non-combustible inorganic substances are included in the inner cavity of wood, the antiseptic and insect repellent properties of wood can be improved.

Furthermore, dimensional stabilization of wood will be explained.

If wood can be swollen and some substance can be fixed in the wood cell walls, dimensional stability can be achieved due to the bulk effect. Inorganic substances can also be used as immobilizing substances. Therefore, dimensional stability can be improved by fixing insoluble, non-combustible inorganic substances into wood cell walls.

However, even if an insoluble, nonflammable inorganic substance is normally dispersed in water and a treatment liquid made of this dispersion is attempted to penetrate into wood, almost only water will penetrate into the wood. This is due to the following reasons. In other words, the narrowest part of the path that the treatment liquid must pass when penetrating into the wood is the pit membrane run, and the pore diameter here is approximately 0.1 μm, whereas the dispersed insoluble and nonflammable This is because the inorganic particles are usually much larger than the pore size of the bit membrane plan.

Therefore, as a method for fixing insoluble nonflammable inorganic substances into the wood, there is a first method using ultrafine particles of insoluble nonflammable inorganic substances, or a second method in which insoluble nonflammable inorganic substances are chemically generated in wood. being developed. The first method is, for example, immersing wood (saturated water treated wood) in a solution in which ultrafine particles of an insoluble, nonflammable inorganic substance are dispersed, and physically impregnating (diffusing) the ultrafine particles into the wood. . The second method is to generate insoluble nonflammable inorganic substances in wood by sequentially impregnating wood with aqueous solutions of multiple types of water-soluble inorganic substances that produce insoluble nonflammable inorganic substances by mixing.

By incorporating insoluble, nonflammable inorganic substances into wood using these methods, it is possible to make the wood flame retardant, rot-preservative/insect repellent, and dimensionally stable.

However, the modified wood obtained by the first and second methods has a problem of poor water resistance. That is, if the modified wood obtained by the first method is once dried and then re-immersed in water, some of the ultrafine particles outside the wood structure will be released into the water. Therefore, it has poor water resistance, and when exposed to rainwater, its flame retardant properties and other properties deteriorate. The modified wood obtained by the second method generally contains a large amount of by-products and unreacted materials in addition to the main constituents, which are insoluble and non-combustible inorganic substances. By-products.

Among the unreacted substances, there are often nonflammable inorganic substances that contribute to improving the flame retardant effect of wood, but they are also often soluble in water. Therefore, when this modified wood comes into contact with rainwater, its flame retardant properties and other properties deteriorate, and its water resistance is often poor. If the water-soluble components of the modified wood are eluted into water in advance, the flame retardance will not decrease, but this will cause the modified wood to have low flame retardancy from the beginning. I often end up. Among water-soluble components, it is convenient to leave as much of the components that contribute to improving the flame retardant effect in the wood as possible.

[Purpose of the invention]

This invention was made in view of the above circumstances, and the purpose is to provide a modified wood that has excellent flame retardancy, antiseptic and insect repellent properties, and dimensional stability, as well as excellent water resistance. There is.

(Disclosure of the Invention) In order to achieve the above-mentioned object, the inventors have conducted repeated research. As a result, they have developed a non-combustible material contained in wood by coexisting with a fixing agent made of a flame-retardant resin. They discovered that it is sufficient to fix the non-flammable inorganic substance within the wood to prevent the non-combustible inorganic substance from falling off, and have now completed this invention.

Therefore, the present invention is a modified wood containing non-combustible inorganic substances in the structure of the wood, in which the shedding of the non-combustible inorganic substances is prevented by a fixing agent made of a flame-retardant resin. Its main feature is modified wood.

The present invention will be explained in detail below.

The modified wood according to the present invention is produced in the following manner.The raw material wood includes raw logs, sawn timber products, sliced veneer 9 plywood, etc., and the type is not particularly limited. The wood containing non-combustible inorganic substances is collected using the following process. In other words, the wood is immersed in a dispersion of ultra-fine particles of non-flammable inorganic substances that are insoluble in water dispersed in water, and the ultra-fine particles are dispersed into the wood. In this case, insoluble in water does not mean that it does not dissolve at all, but also includes cases where it is difficult to dissolve in water, and ultrafine particles are included in the wood (up to the inside of the weave).As ultrafine particles, For example, at least one selected from the group consisting of silicon dioxide, calcium carbonate, aluminum oxide, titanium oxide, etc.
Seeds are used. It can also be created as follows.

That is, by mixing, a plurality of water-soluble inorganic aqueous solutions containing insoluble nonflammable inorganic substances are impregnated in order. Then, by causing the ions contained in each aqueous solution to react with each other, insoluble and nonflammable inorganic substances are generated in the wood.

Specifically, for example, wood is sequentially impregnated with an aqueous solution of Ca Cl z and an aqueous solution of NazPOa adjusted to pH 9 with NaOH to form hydroxyapatite (Calo (P Os ) b (OH) z ) in the wood.
to be generated. Hydroxyapatite contains a phosphoric acid component and has a high flame retardant effect. ■ An aqueous solution of CaC1z,
Na5PO4 and NaC adjusted to pH 9 with NaOH
The aqueous solution of 1 is impregnated into wood in order, and hydroxyapatite and chloroapatite [CaIo (P
O4) a CIg ) is generated. Since chloroapatite contains a phosphoric acid component and a halogen, it has a high flame retardant effect. (2) Impregnate wood with an aqueous solution of 1 g of BaC and an aqueous solution of Na 2 P O 4 # H 2 BO 3 adjusted to pH 9 with NaOH in order to infuse Ba into the wood. (PO4)
s (BOs ) (OI()t) is produced. The obtained inorganic substance contains a phosphoric acid component and a boric acid component, and therefore has a high flame retardant effect.

A fixing agent made of flame-retardant resin is added to wood containing such non-flammable inorganic substances to make it flame-retardant.

Preservation and insect repellency 5. Shedding of nonflammable inorganic substances by water that are effective in maintaining effects such as dimensional stability, i.e. fine particles of nonflammable inorganic substances outside the wood structure (not fixed in the structure) or water-soluble nonflammable substances. To prevent unfixed nonflammable inorganic substances, which are likely to fall off due to flammable inorganic substances, from falling off due to water. If possible, it should be almost permanently established in the wood. As the resin used as the fixing agent, for example, thermosetting resins such as phenol resin, urea resin, and melamine resin are used, and two or more types may be used in combination. These resins are fixed in a form that envelops unfixed inorganic substances within the wood while maintaining adhesion to the wood structure. Furthermore, since it is flame retardant, there is little possibility that the flame retardant effect of the nonflammable inorganic substance will be impaired.

The modified wood thus obtained has excellent flame retardancy, antiseptic and insect repellent properties, and dimensional stability because it contains nonflammable inorganic substances. Furthermore, since the nonflammable inorganic material is prevented from falling off due to water, it has excellent water resistance, and the above-mentioned performance is maintained over a long period of time.

In addition, in the above explanation, only or mainly water-insoluble non-flammable inorganic substances are contained in the wood, but it is also possible to contain only or mainly water-soluble non-flammable inorganic substances in the wood. In some cases. Even water-soluble non-combustible inorganic substances can improve the flame retardancy, antiseptic and insect repellent properties, and dimensional stability of wood, and it is also possible to prevent them from falling off due to water with a fixing agent. be.

Next, examples will be described.

(Example 1) 'lvm thick rotor rotary veneers of pine, cedar and beech wood were each immersed in water. And 20~30wH
The pressure was reduced to about 1.5 g, and each veneer was left to stand for 24 hours to saturate each veneer with water. Next, each obtained water-saturated wood was treated with Ca Cl at 70°C.
The sample was immersed in a z .8 Hz O treatment solution for 5 hours, and further immersed in a treatment solution in which a 40% aqueous solution of Na2POa was adjusted to pH 9 with NaOH and heated to 70°C for 8 hours.

After each piece of wood was dried, it was impregnated with a commercially available phenolic resin adhesive under reduced pressure and cured under heat to obtain three types of modified wood.

All three types of modified wood have a weight increase of 60% relative to 100% absolute dry weight of the wood. Of the 60% weight increase, 20% is due to the phenolic resin component, and the rest is due to the main product hydroxyapatite (Ca + O (P) Oa) b(OH)
z), by-products such as NaCl and unreacted Na3P
It was O4 etc.

The resulting modified wood has excellent flame retardancy, antiseptic properties, and
It had insect repellency and dimensional stability.

When the modified wood was washed with water, almost no weight loss was observed, and excellent flame retardancy, antiseptic and insect repellent properties, and dimensional stability were maintained, and water resistance was extremely excellent.

(Example 2) Three types of water-saturated wood were produced in the same manner as in Example 1. Next, each saturated wood was heated to 70°C with 1t of CaC and 8Ht.
It was immersed in an O treatment solution for 5 hours, and then Na, Po4 and N
A 70° C. saturated aqueous solution of aC1 was immersed in a treatment solution whose pH was adjusted to 9 with NaOH for 8 hours. Example 1 for each wood
In the same manner as above, a phenolic resin adhesive was impregnated under reduced pressure and cured under heat to obtain modified wood. All three types of modified wood have a weight increase of 80% compared to the bone-dry wood type floO, and of the 80% weight increase, 20% is due to the phenolic resin component,
The remainder is the main product hydroxyapatite (Ca+oC
POa ) b (OH)t ) and chloroapatite (Ca+o (POa ) b C1g ).

The resulting modified wood has excellent flame retardancy, antiseptic properties, and
It had insect repellency and dimensional stability.

When the modified wood was washed with water, almost no heavy 'MtjIi was observed, and as in Example 1, excellent flame retardancy, rot and insect repellency, and dimensional stability were maintained, and water resistance was very excellent. Ta.

(Example 3) Three types of water-saturated wood were produced in the same manner as in Example 1. Next, each saturated wood was immersed in a 70°C saturated aqueous solution of BaC1z for 5 hours, and further immersed in Na5POa and HsBO.
A 70° C. saturated aqueous solution of No. 3 was immersed in a treatment solution whose pH was adjusted to 9 with NaOH for 8 hours. Then, in the same manner as in Example 1, a phenolic resin adhesive was impregnated under reduced pressure and cured by heat to obtain a modified wood. All three types of modified wood have a weight increase of 50 compared to the wood bone dry room ji100, and 50
Of the weight increase, 20 was due to the phenolic resin component.

The main product of the reaction is Ba1o (Po4)s (BO3
), or Ba+c+ (PO4)s (BO
3) (OH)z.

All of the obtained modified woods had low specific gravity, but had excellent flame retardancy, rot and insect repellency, and dimensional stability.

When the modified wood was washed with water, almost no weight loss was observed, and as in Example 1, excellent flame retardancy, rot and insect repellency, and dimensional stability were maintained, and water resistance was very excellent. .

(Example 4) In place of the phenolic resin adhesive, a commercially available area resin adhesive was used, and three samples were prepared in the same manner as in Example 1.
Created different types of modified wood.

The obtained modified wood had excellent flame retardancy, rot and insect repellency, and dimensional stability, similar to that obtained in Example 1, and almost no weight loss was observed when washed with water. (water elution #0%) and water resistance was also very excellent.

(Example 5) Three types of modified wood were produced in the same manner as in Example 1, except that a melamine resin adhesive was used instead of the phenolic resin adhesive.

The obtained modified wood had excellent flame retardancy, rot and insect repellency, and dimensional stability, similar to that obtained in Example 1, and almost no weight loss was observed when washed with water. (water elution '40%), and water resistance was also very excellent.

〔Effect of the invention〕

The modified wood according to the present invention is a modified wood that contains nonflammable inorganic substances in the structure of the wood, and the shedding of the nonflammable inorganic substances is prevented by a fixing agent made of a flame-retardant resin. It has excellent flame retardancy, antiseptic and insect repellent properties, and dimensional stability, as well as excellent water resistance.

Claims (2)

[Claims] (1) A modified wood containing non-combustible inorganic substances in the structure of the wood, characterized in that the shedding of the non-combustible inorganic substances is prevented by a fixing agent made of a flame-retardant resin. Modified wood. (2) The modified wood according to claim 1, wherein the resin is at least one selected from the group consisting of phenolic resin, urea resin, and melamine resin.