JPS62116103A - Manufacture of 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] This invention relates to a method for producing modified wood that is imparted with flame retardancy, antiseptic/insect repellent properties, and dimensional stability.

[Background technology]

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.

(a) Coating with inorganic substances...) Promotion of carbonization (C) Inhibition of chain reaction in flaming combustion (d)
Generation of non-flammable gas (e) Heat absorption due to decomposition and release of crystalline water (f) Insulation by foam layer However, conventional treatment methods classified as above cannot produce modified wood with sufficiently satisfactory flame retardancy. That was difficult.

On the other hand, since modified wood is used as a building material, it is also required to have improved antiseptic and insect repellent properties and dimensional stability.

[Purpose of the invention]

This invention was made in view of the above circumstances, and aims to provide a method for producing modified wood that can obtain wood having excellent flame retardancy, antiseptic and insect repellent properties, and dimensional stability. The purpose is

[Disclosure of the invention]

In order to achieve the above object, the inventors conducted repeated research and found that it would be sufficient to incorporate ettringite into wood. This ettringite can be expected to have the effects of the mechanisms (a) and (e) above, and also has antiseptic properties.
This is because improvements in insect repellency and dimensional stability can also be expected. Furthermore, since it is not easily soluble in water, there is little risk of it leaching out of the wood. The mechanisms of (al and (e)) will be explained in detail below. (Even if the inorganic coating of al is a flammable material, if it is combined with a non-flammable inorganic material in an appropriate ratio, it will be difficult to coat with an inorganic material.) This means that it can become combustible.

For example, the conventionally known wood chip cement board is made by mixing combustible wood with noncombustible cement at a weight ratio of approximately 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 heat absorption due to decomposition and release of crystal water in (e) is as follows. Decomposition is, for example, the following ■.

Refers to the release of water by hydroxide, as in reaction (2).

Ca (OH)t -CaO+Hz O↑ ・・・■2
Al(OH)3→A lz 03 +3Hz OT...
・■ Release of water of crystallization is the release of water by inorganic substances that have water of crystallization. Both the decomposition and the release of water of crystallization are endothermic reactions. Therefore, by combining a nonflammable inorganic substance that can undergo such a reaction with a flammable material, the flammable material can be made flame retardant. Ettringite (3CaO-A1.o, 3CaSO
a · nHzO, n = 28 to 32) has a large amount of crystallization water, so the heat absorption effect due to the release of crystallization water is large, resulting in a large flame retardant effect. Next, we will explain how to make wood rot-proof and insect-proof. When fungi cause wood to rot, it is essential that hyphae first invade the inner cavity of the wood. However, if foreign matter is present in the internal cavity of the wood, 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 ettringite is included in the internal 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 allowed to swell and some substance can be fixed in the wood cell walls, a dimensional stabilizing effect can be obtained due to the bulk effect. Inorganic substances that are difficult to dissolve in water can also be used as immobilizing substances. Therefore, fixing ettringite in wood cell walls can improve dimensional stability.

However, even if ettringite, which is difficult to dissolve in water, is directly dispersed in water and a treatment liquid made of this dispersion is attempted to penetrate into the wood, almost only water will penetrate into the wood. This is due to the following reasons. That is,
Among the routes that the treatment liquid should pass when penetrating into the wood,
The narrowest part is the pit membrane plan, and the pore diameter here is about 0.1 μm, whereas the number of dispersed ettringite particles is usually more than 81.Therefore, the inventors further After repeated research, in order to fix ettringite in wood, aluminum ions and calcium ions dissolved in water were used to add Ca(OH)z, CaSO4 or AI to the wood.
After (OH) 3 is once generated, the ions necessary for ettringite generation are impregnated into the wood, and Ca (OH) 3 is generated.
) He discovered that it was sufficient to change z etc. to ettringite, and thus completed this invention.

That is, this invention provides Ca(OH)z, Ca5O
, and at least one of A I (OH)3, MA I O, (M is an alkali metal),
Mz SO4 (M is an alkali metal), Al2 (SO4
)3. and CaX2 (X is /'tO) as a solution, which is appropriately selected for ettringite production, is reacted at pH 8.5 or higher, and ettringite is produced in the wood. Its gist is a method of manufacturing wood that produces .

The present invention will be explained in detail below.

Examples of the wood used in this invention include raw wood logs, sawn timber products, sliced veneer 9 plywood, etc., and the type thereof is not particularly limited.

In order to generate ettringite from ions dissolved in water, it can be obtained by mixing aluminum ions, calcium ions, and sulfate ions at a molar ratio of approximately 2:6:3 at a pH of 8.5 or higher and curing the mixture. . but,
It is not appropriate to treat wood using a treatment solution containing a mixture of each ion and adjusted to pH 8.5 because precipitation occurs in the treatment solution.

Therefore, first of all, Ca (OH), Ca5O, and Al(OH), which can be produced relatively easily and are difficult to dissolve in water,
At least one of these is generated in the wood, and this is further denatured using another treatment liquid, so that ettringite is finally generated in the wood. This will be explained below.

Ca (OH), , Ca5O, and Al (OH)
Wood containing at least one of the following three types is Ca2
After impregnating wood with a treatment solution containing at least one of + and A13+, (:, a (OH) z .

When producing Al(OH)3, it can be obtained by impregnating it with a processing solution containing OH-, and when producing CaSO4, it can be obtained by impregnating it with a processing solution containing SOa.

As a treatment liquid containing Ca2+, for example, CaC1z
(including those with crystal water such as Ca CIz .8 Hz O), treatment liquids containing A13-, for example, A1! Examples of the aqueous solution containing (304) 3 and the treatment liquid containing OH- include an aqueous solution of NaOH, and examples of the treatment liquid containing 804 and OH- include an aqueous solution of NatSO4.

For wood as mentioned above, MA I Oz, Mz S
04, Alt (S04)s and caxz, which are appropriately selected as necessary for ettringite production, are dissolved in water, etc., and impregnated as a treatment liquid, and reacted at pH 8.5 or higher. Generates ettringite in wood. The MA I Ol, etc. may have water of crystallization. M A 10 etc., 2
When using more than one species, it may be impregnated with a treatment liquid in which each species is dissolved, or it may be impregnated with a treatment liquid in which two or more types are dissolved. However, when two or more types are to be dissolved, it is necessary to prevent the reaction from forming insoluble inorganic substances. If one treatment liquid is used, its pH is 1. If two or more treatment liquids are used, if the pH of the last treatment liquid used is less than 8.5, the wood should be further impregnated with a treatment liquid with a pH of 8.5 or higher. This produces ettringite in the wood. M is an alkali metal, usually Na, and X is a halogen, usually CI. p)l of the treatment solution can be adjusted with NaOH or the like.

Next, a more specific explanation will be given. In the case of wood containing Ca(OH)2, for example, a treatment solution (pH 8,
5 or more). Or A1□ (S04)
After impregnation with a treatment solution consisting of a saturated aqueous solution of No. 3, pH
It is impregnated with a treatment liquid consisting of an aqueous NaOH solution adjusted to a concentration of 9. In the case of wood containing CaSO4, for example, Na
A treatment solution consisting of a saturated aqueous solution (pH 8.5 or higher) of AIO is impregnated. Alternatively, A lx (SO4
) After impregnating with a saturated aqueous solution of 3, impregnating with a treatment liquid consisting of an aqueous NaOH solution adjusted to pf (9).
In the case of wood containing (OH)3, for example, CaC
After impregnation with a treatment solution consisting of an aqueous solution of 1, Na was adjusted to pl.

It is impregnated with a treatment liquid consisting of an S Oa aqueous solution. Ca(O
In the case of wood containing H), , Ca5O, and Al(OH)3, for example, MAto, , M2SO4, Alt
(SO4)s and CaX2 are made into an aqueous solution and impregnated. Then, the reaction is carried out at pH 8.5 or higher. However, C
It is preferable that aX, HlSO4, and Alz(Son)i be impregnated in different solutions. One solution is CaS.

This is because 4 can be done.

Impregnation with the treatment liquid is carried out by immersing the wood in the treatment liquid, applying the treatment liquid to the surface of the wood, or the like. Two or more types of impregnation methods may be used in combination.

If necessary, unreacted substances and by-products are removed by boiling the wood in hot water.

The modified wood thus obtained has excellent flame retardancy, rot and insect repellency, and dimensional stability.

Next, an example will be described.

(Example 1) In this example, first, Ca (OH)2 is generated in wood, and Na A I O2 and Naz So.

It was decided to perform treatment with an aqueous solution containing Ca(OH)z to denature Ca(OH)z and generate ettringite.

Two crane thick rotary veneers made of beech, cedar, and pine were immersed in water at room temperature, the pressure was reduced to 1 Torr, and the wood was left for 6 hours to saturate the wood with water. Next, CaCl2 at 70℃
・Immerse saturated wood in an 8H20 aqueous solution, and then adjust the pH
C in the wood by immersing it in a NaOH aqueous solution adjusted to 9.
a (OH)z was produced (precipitated). Wash the wood surface with water and apply NaA10. The sample was immersed in a treatment solution (pH 8.5 or higher) in which water was saturated with Na 2 S Oa at 15° C. for 8 hours to react. 1 for bone dry wood after washing and drying
A modified wood with a weight increase rate of 8% was obtained. This modified wood had excellent flame retardancy, rot and insect repellency, and dimensional stability due to the effects of ettringite.

(Example 2) Ca (OH)2 was generated in wood in the same manner as in Example 1, and then a saturated aqueous solution of Alz (SOa) was impregnated into the wood at room temperature, and the NaOH aqueous solution was adjusted to pH 9. It was immersed in the liquid for 8 hours at room temperature. After washing with water and drying, a modified wood with a weight increase rate of 42% compared to the bone-dried wood was obtained. This modified wood had excellent flame retardancy due to the effect of ettringite, and also had excellent dimensional stability with an expansion and contraction ability (ASE) of 38%. It also had excellent antiseptic and insect repellent properties.

(Example 3) In this example, first, CaSO4 was generated in the wood, and then Na A I O was treated with an aqueous solution, and C
It was decided to generate ettringite by denaturing a5o4. Two thick rotary veneers made of beech, cedar, and pine are immersed in water at room temperature and subjected to IT.

The wood was saturated with water by reducing the pressure to rr and leaving it for 6 hours. Next, the saturated wood was immersed in an aqueous solution containing CaC1z"8HzO at 70°C, and
The wood was immersed in a saturated aqueous solution at 0°C to generate Ca5O in the wood. Wash the wood surface with water and store it at room temperature.
It was immersed in z-saturated aqueous solution 1 (pH, 5 or more) for 8 hours to react. After washing with water and drying, a modified wood with a weight increase of 21% compared to the bone-dried wood was obtained. This modified wood had excellent flame retardancy, rot and insect repellency, and dimensional stability due to the effects of ettringite.

(Example 4) CaSO4 was generated in wood in the same manner as in Example 3, and then a saturated aqueous solution of Alt(SO4)z was impregnated into the wood at room temperature, and then it was soaked in an aqueous NaOH solution adjusted to pH 9. It was soaked for 8 hours at room temperature. After washing with water and drying, a modified wood with a weight increase rate of 36% compared to the bone-dried wood was obtained.

Due to the effects of ettringite, this modified wood has excellent flame retardancy, rot and insect repellency, and dimensional stability (ASE = 31
%).

(Example 5) In this example, first, Al (OH)3 was generated in wood, treated with CaCl2 aqueous solution, and further treated with Na, So,
It was decided to perform treatment with an aqueous solution to modify Al(OH)s and obtain ettringite. 2N each of beech, cedar, and pine
Immerse a thick rotary veneer in water at room temperature, l'l'or
The wood was saturated with water by reducing the pressure to r and leaving it for 6 hours. Next, the wood was immersed in a saturated aqueous solution of Atz (SOa) 3 at 70° C. for 3 hours, and further immersed in an aqueous NaOH solution at room temperature adjusted to pH 8. During the process, pn changed to the acid side, so it was necessary to add NaOH to adjust the pH fl. This results in A I (OH) in the wood.
3 was generated. Wash the surface with water and place it in CaC1z at 70℃.
・After soaking the wood in 8H30 for 3 hours, plating with NaOH
It was immersed for 8 hours in a 70°C Na2SO4 aqueous solution adjusted to H9 to react. 4 for bone dry wood after washing and drying
A modified wood with a weight increase rate of 4% was obtained. This modified wood had excellent flame retardancy, rot and insect repellency, and dimensional stability (ASE=38%) due to the effects of ettringite.

〔Effect of the invention〕

The method for producing modified wood according to this invention includes Ca(0)()
MA 10. (M is an alkali metal), MZ SO4 (M is an alkali metal),
Alz (504) 3. and CaX2 (X is a halogen), which is appropriately selected as a solution for ettringite production, and impregnated with a solution.
The reaction is carried out at a pH of 8.5 or higher to produce ettringite in the wood, resulting in flame retardant, antiseptic and
Modified wood with excellent insect repellency and dimensional stability is obtained.

Claims (1)

[Claims] (1) Ca(OH)_2, CaSO_4 and Al(O
H) MAl on wood containing at least one of _3
O_2 (M is an alkali metal), M_2SO_4 (M is an alkali metal), Al_2(SO_4)_3, and Ca
A modification that produces ettringite in wood by impregnating it as a solution with a solution selected from the group consisting of Wood manufacturing method.