JPH05116107A - Method for producing modified wood - Google Patents

Abstract

(57) [Summary] [Object] The present invention aims to mass-produce flame-retarded wood by a simple manufacturing method. According to the present invention, the wood is impregnated with a water-soluble inorganic chemical and dried, and then the wood is impregnated with a solution of a metal alkoxide, and then the metal alkoxide is hydrolyzed or thermally decomposed to obtain a wood alkoxide. A method for producing modified wood in which a non-flammable metal oxide is changed and a water-soluble inorganic chemical impregnated in the wood is wrapped in the process of changing to the metal oxide so that the inorganic compound is prevented from being eluted by the action of water. is there.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing flame-retarded wood, and particularly to prevent the water-soluble inorganic chemicals impregnated in wood from being eluted by the action of water, thereby imparting flame retardancy to wood. The present invention relates to a method for producing the modified wood.

[0002]

2. Description of the Related Art The Building Standards Act was revised in June 1990, and wood can now be used for openings. However, it was necessary to clear the flame penetration and flame barrier standard of 60 minutes for A and 20 minutes for B, and it was difficult to exceed this standard even if wood was used as it was. On the other hand, conventionally, in order to make wood flame-retardant, various manufacturing methods as exemplified below have been carried out.

The first manufacturing method uses a water-soluble inorganic compound such as boric acid, borax, or ammonium phosphate as a flame retardant for wood, and impregnates this water-soluble inorganic compound into wood. Is a flame-retardant manufacturing method. When impregnating these water-soluble inorganic compounds in wood, it is replaced by a high-concentration water-soluble flame retardant by the reduced pressure and pressure injection method or by immersing the wood in water for a long time to keep it saturated. The method is taken.

The second manufacturing method is silicon ethoxide,
It is a method in which an alkoxide such as silicon methoxide is used to react with a hydroxyl group of a wood material by hydrolysis or heat polymerization or to be polymerized to generate a silicone polymer. The flame-retardant chemicals conventionally used for flame-retarding wood rarely show sufficient flame-retardant effect with a single chemical,
It is common to utilize a synergistic effect by using a mixed drug of two or more kinds.

[0005]

However, in the case of the above-mentioned first production method, it takes a considerable amount of time to impregnate the wood with the water-soluble drug, and the compound impregnated into the wood is Since it is water-soluble, it not only loses its flame-retardant effect by leaching from the wood due to contact with water or moisture in the air, but the leached components also adhere to the surface of the wood, reducing the adhesive effect and painting effect There was a problem that made processing difficult. In addition, there is a problem that these water-soluble agents may cause swelling of wood due to moisture absorption, which may lead to contamination of wood and corrosion of metals such as nails.

Further, in the case of the above-mentioned second production method, since the emphasis is originally placed on improving the heat resistance, weather resistance, water resistance, stain resistance, chemical resistance, etc. of wood. However, the flame retardancy of wood is not sufficient, and it has been difficult to reliably manufacture modified wood that complies with the new building standard law.

The manufacturing method according to the present invention is a new technique developed in view of the above-mentioned conventional problems, and can be applied as a member of an opening based on the new Building Standard Law, and further, it is a building interior material. An object of the present invention is to provide a manufacturing method capable of easily and reliably manufacturing flame-retardant wood that can be used as an exterior material. In particular, the present invention uses a low-priced water-soluble inorganic compound as a flame retardant for wood. After impregnating wood with an inorganic compound, it is further impregnated with a metal alkoxide and then hydrolyzed or thermally decomposed to form a metal. It is an object of the present invention to provide a completely new technique for preventing the elution of water-soluble inorganic chemicals impregnated in wood into water by forming oxides, thereby effectively imparting flame retardancy to wood.

[0008]

The method for producing modified wood according to the present invention is a technique which has fundamentally improved the above-mentioned problems of the prior art, and the gist thereof is one or more water-soluble substances. After the wood is impregnated with an inorganic chemical and dried, the wood is further impregnated with a solution of one or more metal alkoxides, and then hydrolyzed or thermally decomposed to make the metal alkoxide noncombustible and insoluble in wood. This is to prevent the elution of inorganic compounds into water by changing to the metal oxide of (3) to make wood flame-retardant.

[0009]

In the method for producing modified wood according to the present invention,
After the wood is impregnated with the water-soluble inorganic agent having flame retardancy as described above and dried, the wood is further impregnated with a metal alkoxide, and the metal alkoxide is converted to a flame retardant metal oxide by heating or hydrolysis. In addition, since the water-soluble inorganic chemicals are wrapped in the process of changing into metal oxide, it is possible to prevent the inorganic compound impregnated in wood from being eluted by the action of water. Therefore, the wood can be impregnated with a flame-retardant metal oxide and a flame-retardant inorganic agent that does not elute in water, respectively, whereby the wood is stable and stable for an extremely long period of time. Flammability can be imparted.

[0010]

EXAMPLES As described above, the method for producing a modified wood according to the present invention comprises preparing a composite solution in which one or more kinds of metal alkoxides having a fireproof effect are combined to prepare a solution thereof. Manufactured by impregnating wood with an inorganic chemical in advance, then removing the wood from the solution and subjecting it to hydrolysis or heat decomposition to convert the metal alkoxide to metal oxide in the wood and then drying the wood. A method for producing a flame-retardant modified wood.

Next, the characteristics of the metal alkoxide and the water-soluble inorganic drug used in the present invention will be described in detail. The metal alkoxide solution used in the present invention, whether a single solution or a composite solution, can be easily impregnated into wood, and the wood can be used as it is without pretreatment. Further, the impregnation is carried out at normal pressure and quickly without using pressure reduction or pressure injection. On the other hand, water-soluble inorganic chemicals are cheap in price, but when they are suitable for moisture in the air or water, they flow out from the wood and not only reduce the flame retardant effect, but they also adhere when wood is secondarily processed. It has drawbacks such as impairing sex.

The above-mentioned metal alkoxide used in the present invention is converted into a water-insoluble metal oxide by hydrolysis or thermal decomposition, and further wraps a water-soluble inorganic drug in the process of changing to a metal oxide, It has the property of preventing elution with water. When the wood is impregnated with the inorganic chemical, it is preferable to make the wood saturated with water in advance and immerse the wood in an aqueous solution of the inorganic chemical, or to use a reduced pressure or pressure injection method. Next, when the metal alkoxide solution is impregnated, it is sufficient to impregnate the wood with the metal alkoxide solution or a composite solution thereof as it is, but of course, it may be impregnated using a reduced pressure and pressure injection method. The hydrolysis step may be performed on the acidic side or the alkaline side. The wood impregnated with the metal alkoxide can be immersed in water and boiled, but steam heating is more preferable. When hydrolyzing on the acidic side, it is preferable to add mineral acids such as hydrochloric acid and nitric acid to water and steam, and when hydrolyzing on the alkaline side, ammonia is added to water and steam. Further, by heating and drying the wood impregnated with the metal alkoxide, the metal alkoxide can be completely converted into the metal oxide.

The inorganic compounds used in the present invention include monoammonium dihydrogen phosphate, diammonium monohydrogen phosphate, ammonium borate, ammonium sulfate, ammonium chloride, ammonium bromide, ammonium fluoride, boric acid,
Examples include borax, sodium silicate, potassium bromide, zinc chloride, zinc bromide, magnesium bromide, magnesium chloride, calcium chloride, lithium chloride and zinc sulfate. The general formula of the metal alkoxide used in the present invention is M (OR) n. In the formula, M is a metal, R is an alkyl group having 1 to 12 carbon atoms, and n is a metal valence and is an integer of 1 to 5. M is Na,
K, Li, Ba, Ca, Sr, Mg, Zn, Sn, S
b, B, Si, P, Ti, Al, Zr, Ta, Nb, G
Metals such as e, Fe, Co, Ni, V, and Mn. R is a methyl, ethyl, propyl, isopropyl, butyl, hexyl, octyl, decyl or dodecyl group. n is 1
If it becomes a long-chain alkyl group larger than 2, for example, a stearyl group, it remains in the wood after the drying step, causes combustible components, and promotes combustion by returning, so C is 1
It is preferable to use methyl, ethyl, propyl, isopropyl and butyl groups of up to 4.

In making the composite solution of the water-soluble inorganic compound, any combination of the inorganic compounds listed in the present invention is possible. When making a composite solution of metal alkoxide, it is possible to combine all the metals listed in the present invention, but if the alkoxy groups of the two metals are different, substitution of the alkoxy group occurs depending on the type of metal, Another metal alkoxide having low solubility in a solvent such as alcohol or hydrocarbon is produced, which causes precipitation. It is preferable to use a combination of metal alkoxides in which the same kind of alkoxy groups are reacted. Of course, even if the alkoxy groups are different, precipitation does not occur, and there are many transparent complex solutions, which are not limited to the above. Further, when preparing a composite solution of metal alkoxide, a solution of the metal alkoxide as it is may be composited, or a solution diluted with a solvent such as alcohol, acetone, aliphatic hydrocarbon or aromatic hydrocarbon may be mixed and used. I don't care. When wood is impregnated with a single solution or a mixed solution of an inorganic compound, the wood is preliminarily saturated with water and immersed in an aqueous solution of the inorganic compound, or a reduced pressure or pressure injection method is used. Next, the wood impregnated with the inorganic compound is dried at 60 to 90 ° C.

As a method of impregnating wood with the metal alkoxide single solution and the composite solution, there is a method of immersing wood in these solutions as it is or injecting it under reduced pressure. When the method of injecting under reduced pressure is used, the wood is efficiently impregnated in a short time. Then, the metal alkoxide-impregnated wood is impregnated with water, and the metal alkoxide is hydrolyzed by boiling, passing steam, or heating and drying to convert into metal oxide in the wood. Then, it is put in a dryer and dried at 60 to 90 ° C. to obtain modified wood. This modified wood is treated with the oxygen index method (JIS-K
A combustion test was performed using a test method according to 7201) and compared with the blank. It was found that the modified wood treated with the water-soluble inorganic chemical and then with the metal alkoxide had a uniformly higher oxygen index than the blank and contributed to flame retardancy.

Next, the contents of the present invention will be described in detail with reference to specific examples. [Example 1] Single board of cypress 210 x 70 mm, thickness 0.3 m
m in a vacuum desiccator and diammonium hydrogen phosphate and sodium tetraborate 1:
It was immersed in the solution of 1 for 1.5 hours. Then, this impregnated veneer was dried at 65 ° C. for 15 hours and then immersed in a triethyl borate solution at 1.5 mm under reduced pressure for 1.5 hours. Then, the impregnated wood was hung in a 5 L beaker containing 1 L of ammonia water having a concentration of 1.45%, the beaker was heated to hydrolyze triethyl borate under ammonia alkaline steam for 1 hour, and then the wood surface was removed. 65 ℃ after washing with water
When the sample dried for 15 hours was measured using the oxygen index measurement method of JIS-K7201, the blank oxygen index was 19%, whereas the modified wood was 55.5%.

[Examples 2 to 11] By the same operation method as in Example 1 above, the amount of the inorganic chemical in the impregnating liquid of the first liquid was changed, and the amount was changed by using various metal alkoxides in the second liquid. Obtained modified wood. The results are shown in Table 1.

[0018]

[Table 1]

[Examples 12 to 14] Cypress single plate 210 × 7
0 mm, thickness 0.3 mm was put in a vacuum desiccator, and the liquid concentration and dipping time of a 1: 1 solution of diammonium monohydrogen phosphate and sodium tetraborate were changed under reduced pressure at 10 mmHg to obtain the impregnation amount of the example. Was prepared as follows. After that, the impregnated wood is dried at 65 ° C. for 15 hours to obtain JIS-K720.
The oxygen index was measured by the oxygen index measuring method of 1.

[Embodiment 15] Single board of cypress 210 x 70 m
m, thickness 0.3 mm was put into a vacuum desiccator, and immersed in a 1: 1 solution of diammonium monohydrogen phosphate and sodium tetraborate under reduced pressure at 10 mmHg for 1.5 hours. After that, the impregnated veneer was dried at 65 ° C. for 15 hours and then immersed in a triethyl borate solution at a reduced pressure of 10 mmHg for 1.5 hours. Thereafter, the impregnated wood was treated with 1 L of a nitric acid solution having a concentration of 3.15%. Suspend it in a 5L beaker and heat the beaker to hydrolyze triethyl borate under nitric acid and acid steam for 1 hour.
When the sample dried at 15 ° C. for 15 hours was measured by the oxygen index measurement method of JIS-K7201, the blank oxygen index was 19%, whereas the modified wood had 87.5%.

[Examples 16 to 25] In the same manner as in Example 15, the amount of the inorganic chemical in the first liquid impregnating liquid was changed, and the amount was changed by using the metal alkoxide in the second liquid. Modified wood was obtained. The results are shown in Table 2.

[0022]

[Table 2]

[Example 26] Single board of cypress 210 x 70 m
m, thickness 0.3 mm was put into a vacuum desiccator, and immersed in a 1: 1 solution of diammonium monohydrogen phosphate and sodium tetraborate under reduced pressure at 10 mmHg for 1.5 hours. Thereafter, this impregnated veneer was dried at 65 ° C. for 15 hours and then immersed in a triethyl borate solution at 10 mmHg under reduced pressure for 1.5 hours. Thereafter, the impregnated wood was heated for 20 hours in a blow dryer at 110 ° C. to thermally decompose the metal alkoxide. When this sample was measured using the oxygen index measurement method of JIS-K7201, the blank oxygen index was 19%.
However, the modified wood was 50.5%.

[Examples 27 to 32] Modified woods were obtained using various metal alkoxides by the same operation method as in the above examples. The results are shown in Table 3.

[0025]

[Table 3]

As in the examples of Table 1, Table 2 and Table 3, modified wood obtained by impregnating an inorganic chemical with the first liquid, then impregnating a metal alkoxide, and then hydrolyzing or thermally decomposing It was found that the oxygen index was higher than both the blank and the impregnation of the inorganic chemical alone, which contributed to flame retardancy. It was also found that the oxygen index differs depending on the method of decomposing the metal alkoxide. That is, it was found that the oxygen index was improved in the order of ammonia hydrolysis, nitric acid hydrolysis, and thermal decomposition.

[Examples 33-40] Examples 1, 15 and 2
The modified wood obtained by the same operation method as in 6 was put in a 2 L beaker, 2 L of pure water was added, and the mixture was stirred at 25 ° C. for 4 hours to conduct a water extraction test of the impregnated drug. Then, the water-extracted modified wood was dried at 65 ° C. for 15 hours and measured using the oxygen index measurement method of JIS-K7201. The inorganic chemicals were completely extracted with water, and the oxygen index was 19%, which was the same as the untreated one. On the other hand, the wood treated with metal alkoxide prevented the elution of the inorganic chemicals, and the oxygen index after the water extraction test was also It was uniformly high. The results are shown in Table 4.

[0028]

[Table 4]

In the water extraction test after impregnation with chemicals as in the above Examples, the modified wood treated with metal alkoxide was completely extracted into water with the inorganic chemical alone and the chemical was not retained in the wood. It was found to be retained mostly in wood with a slight weight loss. It was also found that the oxygen index after chemical extraction was 19% with the inorganic chemical alone like the blank, whereas the modified wood was good and maintained the flame retardant effect even after water extraction. ..

[0030]

EFFECTS OF THE INVENTION The method for producing modified wood according to the present invention has the above-described structure and action. Therefore, by using a metal alkoxide for an inexpensive inorganic drug, the elution of the inorganic drug into water is prevented. Moreover, it is possible to maintain an excellent flame retardant effect even after the water elution test. As a result, the chemicals are not extracted from the wood even if it is exposed to rainwater or dew condensation, and the adhesiveness and coating performance during processing are not impaired, and dimensional stability can be imparted. By carrying out the method for producing modified wood according to the present invention, a large amount of flame-retarded wood that can be used as a member of an opening conforming to the New Building Standard Law, or as a building interior material or exterior material at low cost. It is characterized by being able to be produced.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Sakata 2-20-5 Shimotani, Taito-ku, Tokyo Within Nippon Kagaku Kogyo Co., Ltd. (72) Inventor Shigehisa Ishihara 3-33-12 Tenjin, Nagaokakyo, Kyoto Prefecture

Claims (1)

[Claims] 1. Wood is impregnated with one or more water-soluble inorganic chemicals and dried, and then the wood is further impregnated with a solution of one or more metal alkoxide, followed by hydrolysis or thermal decomposition. The method for producing modified wood is characterized in that the metal alkoxide is converted into a metal oxide that is non-combustible and insoluble in wood to prevent the elution of inorganic compounds into water to make the wood flame-retardant.