JPH0245102A - Reforming method of lumber material - Google Patents

Abstract

PURPOSE:To impart a lumber material with an excellent dimensional stability, preservative property, mothproof property, fire retardant and the like, and reform the lumber at a low cost by impregnating a solution having one or more ingredients respectively of a soluble organic polybasic acid and the acid salt of phosphoric acid to the lumber material. CONSTITUTION:A lumber is soaked into the organic solution of organic polybasic acid and the acid salt of phosphoric acid, and impregnated with said solution. By heating and drying them, the organic polybasic acid and the active group of hydroxyl group or the like in the lumber component produce a hydrate condensing reaction at the same time of drying by the catalytic action of the acid salt of phosphoric acid, and then bond chemically, thereby giving a dimensional stability, fire retardant, mothproof property, preservative property and the like, moreover, these properties come to be maintained for a long time.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention maintains the decorative properties and cutting properties inherent to wood, while adding dimensional stability, antiseptic properties, insect repellency, flame retardancy, hardness, etc. to the wood. The present invention relates to a method for modifying wood to impart properties such as:

[Conventional technology and its problems]

BACKGROUND ART Conventionally, wood has been modified by coating and impregnating it with an aqueous solution such as phosphoric acid to make it flame retardant and to improve its antiseptic and insect repellent properties.

However, even if these treatments are performed, there is a problem that the treated substances are eluted from the wood by rainwater and the like, and their effectiveness is easily lost in a short period of time.

On the other hand, acetylation with acetic anhydride or the like is also being carried out to improve the dimensional stability of wood, insect repellency, and other effects.

However, acetylation with acetic anhydride has problems in that the materials and equipment used in the treatment method are expensive, and acetic acid is produced as a by-product.

Another method is to inject resin into the voids of wood to modify it, and it is well known that it improves strength and cosmetic properties, but simply filling with resin does not provide fire protection or high dimensional stability. It was difficult to make it give.

The present invention was made in view of these problems, and it is a method that easily imparts excellent dimensional stability, antiseptic properties, insect repellency, flame retardancy, etc. to wood, and improves it comprehensively and at low cost. The purpose of the present invention is to provide a method for modifying wood.

[Means for solving problems]

In order to achieve the above object, the method for modifying wood according to the present invention involves impregnating wood with an aqueous solution containing at least one of each of a water-soluble organic polybasic acid and an acid salt of phosphoric acid as essential components, and then heating the wood. It is characterized by drying.

Furthermore, the present invention is characterized in that a liquid epoxy compound that reacts with acidic groups existing unreacted in the modified wood obtained by the above method is applied to and impregnated into the wood.

The water-soluble organic polybasic acids used in the method of the present invention include maleic acid, aconitic acid, isocamphoronic acid,
Citric acid, glutaric acid, citraconic acid, tartaric acid, methylsuccinic acid, malic acid, polymaleic acid, polyacrylic acid, polymethacrylic acid, etc., but particularly preferred are maleic acid, polymaleic acid, polyacrylic acid, polymethacrylic acid. such as acids.

Note that if the molecular weight of these organic polybasic acids exceeds 20,000, it becomes very difficult to impregnate wood, so it is practically preferable that the molecular weight is 20,000 or less.

In addition, acid salts of phosphoric acid used with organic polybasic acids include diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium hydrogen phosphonate, sodium hydrogen phosphonate, disodium hydrogen phosphate, and sodium dihydrogen phosphate. , disodium dihydrogen hypophosphate, disodium dihydrogen birophosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, calcium dihydrogen phosphate, ammonium sodium hydrogen phosphate, etc., but preferred is phosphoric acid. Ammolyrum dihydrogen, diammonium hydrogen phosphate.

These acidic compounds are used as an aqueous solution, but the concentration is below the saturation concentration, usually 5 to 60%.

The ratio of organic acid to acidic phosphate is 10-95:90
-5, if a higher anti-swelling ability against water is expected, the proportion of the organic polybasic acid may be increased.

When wood impregnated with an aqueous solution of these acidic compounds is heated and dried, a dehydration condensation reaction occurs between the organic polybasic acid and the wood due to the catalytic action of the acidic phosphate, although there are differences depending on the temperature and time, as well as bulking. It is thought that this also provides anti-swelling ability due to water absorption.

However, since unreacted acidic groups also exist, the effect can be further enhanced by sealing them.

For this reason, it is preferable to use liquid epoxy compounds in the method of the present invention, examples of which include the following.

Epoxidized higher fatty acid esters by peroxidation, such as epoxidized linseed oil, epoxidized soybean oil, epoxy compounds of linseed oil and soybean oil fatty acid monoester, styrene oxide, phenyl glycidyl ether, glycidyl ether of aliphatic polyhydric alcohols Examples include ethylene glycol, diethylene glycol, triethylene glycol, neopentyl glycol, polypropylene glycol (polymerization degree of 30 or less), polyethylene glycol (polymerization degree of 20 or less), glycerin, di-triglycidyl ethers such as trimethylolpropane, etc. Especially preferred are epoxidized soybean oil and epoxidized linseed oil.

There are various ways to carry out the present invention, but the most typical method is to first immerse wood (plate-shaped, columnar, dried or undried wood) in the above-mentioned acidic aqueous solution, then apply reduced pressure and It is impregnated with an acidic aqueous solution using pressure and other operations, and then heated and dried.

The drying temperature is 80 to 160°C for veneer, preferably 1
What is necessary is just to carry out at 00-130 degreeC for 5-1 hour.

[Function] When wood is immersed in an aqueous solution of an acidic salt of an organic polybasic acid and phosphoric acid to impregnate it with the aqueous solution and then heated and dried, the organic polybasic acid and the organic polybasic acid are simultaneously dried due to the catalytic action of the acidic phosphate. Active groups such as hydroxyl groups in wood components undergo a dehydration condensation reaction and chemically bond, resulting in dimensional stability, flame retardancy, insect repellency, antiseptic properties, etc., which are maintained over a long period of time. It turns out.

The effect of dimensional stabilization is thought to be that the polymer is filled into the microscopic voids of the wood cell wall due to the above reaction, and dimensional stability (anti-swelling property against water absorption) is imparted due to the bulking effect.

At this time, the acidic phosphate has the effect of preventing discoloration of the treated wood, and the treated wood at this stage has the original appearance of the wood.

Furthermore, such modified wood has inferior properties such as staining properties, and unreacted acidic groups are also present in the wood, so this modified wood is impregnated with a liquid epoxy compound.
When heated to 160'C, unreacted acidic groups are cured by coating and impregnating with a liquid epoxy compound, and resin fills into the wood voids, increasing transparency.
A treated wood exhibiting the appearance of WPC is obtained.

This wood is superior in hardness, stain resistance, and appearance to the modified wood obtained in the first step, and all the impregnating agents are stably retained in the wood.

Note that the liquid epoxy compound may be one without a catalyst and without a curing agent, but a known curing catalyst and curing agent may be used in combination if necessary. In particular, ultraviolet curing catalysts and latent catalysts (
cationic polymerization type, etc.) give favorable results.

Hereinafter, the present invention will be explained in more detail with reference to Examples, but these do not include all aspects of the present invention.

[Example 1] A thickness of 1 ml was added to an aqueous solution containing 22% polyacrylic acid (molecular weight -4,000) and 12% ammonium dihydrogen phosphate.
, Soak 3mm Hemlock veneer and Douglas fir veneer, 3
The aqueous solution was impregnated by applying a vacuum of 0 torr and heated at 105°C.
It was dried for 3 hours.

As a result, the weight of Japanese hemlock veneer increased by about 50%, and the weight of Douglas fir veneer increased by about 40%.

These treated veneers were flame retardant, carbonized without producing smoke even when exposed to flames, and had antiseptic and termite properties.

In addition, these treated veneers were immersed in water at room temperature, the water was absorbed under a reduced pressure of 30 Torr, and then washed and dried. As a result, the extracted bone content of the treatment agent was 37%, and it was found that the extracted bone content of the treatment agent was 37%, and the amount of bone extracted by the treatment agent was 37%. The flame retardant extract was superior compared to the 80% extracted bone in the same procedure.

Subsequently, when the ASE of the treated hemlock and Douglas fir veneers was immersed in ion-exchanged water for 48 hours,
Values of 78% and 64% were obtained, respectively.

[Example 2] The acidic phosphate aqueous solution of Example 1 was coated with a thickness of 1 and 3#l11.
The aqueous solution was impregnated into the veneer by immersing a Hemlock veneer and applying a vacuum of 30 torr, and then immersing the veneer at 110°.
It was dried at C for 2 hours. As a result, the weight increase of the veneer is 5
It was 1%.

A liquid epoxy compound prepared by dissolving 0.3% of a latent cationic curing agent (Asahi Denka Opton CP-66) as a curing catalyst in epoxidized linseed oil (containing 9% oxirane oxygen) was applied to this treated veneer at 40°C and 230°C. Impregnation was carried out under Torr vacuum conditions.

Thoroughly wipe off the epoxidized linseed oil that has adhered to the surface, and
After curing for 2 hours at 05°C, the epoxidized linseed oil impregnation was 32% based on the initial veneer weight.

Like the treated veneer obtained in Example 1, this treated veneer has flame retardant, antiseptic, and termite-proofing properties, as well as high hardness and a highly transparent appearance. It had fire extinguishing properties.

This treated veneer was immersed in ion-exchanged water, impregnated with water under a reduced pressure of 30 torr, and thoroughly washed, resulting in an extractable content of about 5%.

On the other hand, about 80% of commercially available ammonium phosphate flame retardants can be extracted in the same procedure, and compared to this, they are extremely stable.

Furthermore, the veneer after water extraction was also self-extinguishing and produced a relatively hard carbide. Furthermore, the ASE value determined in the same manner as in Example 1 was about 80%.

[Example 3] A hemlock veneer and a Douglas fir veneer with a thickness of 1.3 a + m were immersed in an aqueous solution containing 20% maleic acid and 10% ammonium dihydrogen phosphate, and impregnated with the aqueous solution under a reduced pressure of 30 Torr. "C" for 6 hours.

As a result, the weight increase rate was 46% for Japanese hemlock and 3% for Japanese hemlock.
It was 9%.

These treated veneers were then impregnated with epoxidized linseed oil and cured in the same manner as in Example 2.

The impregnation rate of epoxidized linseed oil was 40% based on the initial weight of the veneer.

The treated veneer thus obtained has a hard and beautiful appearance of WPC, and also has self-extinguishing and termite-proofing properties, and the ASE value determined in the same manner as in Example 1 was 62%. Ta.

〔Effect of the invention〕

As described above, in the wood modification method of the present invention, wood is impregnated with an aqueous solution containing at least one of each of a water-soluble organic polybasic acid and an acidic phosphate as an essential component, and then heated and dried. It is flame retardant for a long period of time.
Modified wood that exhibits rot-preservative and insect-repellent properties can be easily obtained, and by coating or impregnating this modified wood with a liquid epoxy compound and curing it, it has excellent dimensional stability and appearance. This makes it possible to obtain wood that exhibits the following characteristics, and to provide wood that is extremely useful for applications such as building materials.

Claims (2)

[Claims] (1) A wood modification treatment characterized by impregnating wood with an aqueous solution containing at least one of each of a water-soluble organic polybasic acid and an acidic phosphate as an essential component, and then heating and drying the wood. Method. (2) After impregnating wood with an aqueous solution containing at least one of each of a water-soluble organic polybasic acid and an acidic phosphate as essential components and drying by heating, the wood is further coated or impregnated with a liquid epoxy compound. A method for modifying wood, which comprises curing the wood.