JPH0321401A - Fire prevention treatment for lumber - Google Patents

Abstract

PURPOSE:To act effectively upon even extermination of a harmful insect by having fire prevention properties and fire retardant properties, by a method wherein the lumber is heat-treated, pressurization-treated and immersed into an atmosphere of an organic boron compound and the compound is infiltrated into the lumber. CONSTITUTION:A rubber tree is put into a pressure vessel, treated with pressurized saturated steam, equilibrium moisture content of former lumber is made low by 2-4% and heat-treated and pressurization-treated lumber whose rate of anti-expansion is 20-60% is obtained. Then, after the depressurization by putting the same into an airtight vessel, an organic boron compound, for example, steam of trimethyl borate is introduced, made into atmospheric pressure and infiltrated into the same. The organic boron compound infiltrated into the lumber is resolved with water contained in the lumber and fine boron oxide and boric acid are formed within a lumber texture for modification of the lumber.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for fireproofing wood to impart fire resistance, combustion prevention and pest control to the wood.

Previously, in order to impart fire resistance and flame retardancy to wood, methods of infiltrating the interior of wood by immersing it in a vapor casing containing an organic boron compound or in a liquid diluted with a solvent have been studied. However, there was a problem that it did not penetrate sufficiently. This is thought to be because most of the compound penetrates into the amorphous part of cellulose in the wood.

OBJECT OF THE INVENTION An object of the present invention is to provide a fire prevention treatment method that modifies the cellular structure of wood to facilitate the penetration of organoboron compounds. During pressure operation, the absolute value of the equilibrium moisture content (Ki) of the original wood is lowered by 2 to 4 times, and the anti-swelling rate is reduced by 2.
A method for fire prevention treatment of wood, in which a heated and pressurized product with a concentration of 0 to 60% is immersed in an atmosphere of an organoboron compound to infiltrate the compound into the interior, and is decomposed by the contained moisture to generate boron oxide and boric acid within the wood structure. It is.

Here, the anti-swelling coefficient is ASE (Anti-S
wellingEfficiency7) using the following formula.

Do D AS'E= Although heating and pressurization using a compressor, heating and pressurization using steam or water vapor are possible, heating and pressurization using steam is safe and economical. The heating and pressurizing conditions are 120
~250°C, 2~4ok9/d. Processing time varies depending on temperature and pressure, for example, rubber wood and thickness! ) In the case of OIE II plate material, 120°c. After treatment at 2 ky/d for 8 hours and at 210'c and 20 k/d' for 30 minutes, the absolute value of the equilibrium moisture content was lowered by about 21 points, and the anti-swelling rate was about 20 points lower. In addition, after treatment at 150°C, s #/ci for 16 hours, or at 250°C, 40 #/cd for 2 hours, the equilibrium moisture content was about 41 at the lowest, and the anti-swelling coefficient was about 601. . If the temperature is below 120°C, the wood will not be modified and the effect of the present invention will not be obtained, and if the temperature is above 250°C, the natural texture of the wood will deteriorate due to the high heat required for operation. The mechanical strength was significantly reduced.

Wood treated with heat and pressure in this way loses weight by about 10 kg due to the elution of hemicellulose with a high equilibrium water content in the wood, and the change in equilibrium water content due to environmental changes is significantly less, resulting in a change in size. Reduce the rate of change. The structure has more voids and a more porous structure due to the elution of hemicellulose, making it easier for organic boron compounds to penetrate in the next step. , into a recognized shape such as a chip, using an organic boron compound such as trimethyl borate, trimethoxyboroxine, etc.
It is immersed in an atmosphere consisting of the vapor of one of these or a mixture of two or more thereof, or a liquid diluted with a volatile solvent such as methanol.

Since the solution obtained by diluting one cigarette of organoboron compound vapor in a solvent is not an aqueous solution, wood immersed in such an atmosphere needs to be dried in a special drying facility (although it is sufficient to simply leave it in the air). However, by decomposing penetrating organoboron compounds with the moisture contained in the wood, the moisture absorbed from the atmosphere, and especially the moisture applied, substances with fire resistance and combustibility are created. Since it is generated naturally, forced drying will give better results. In addition, the fire resistance and flame retardance can be adjusted arbitrarily by adjusting the concentration of the atmosphere and the soaking time, and by adjusting these according to the material and size of the wood, it is possible to sufficiently penetrate the inside of the wood. In the case of steam, it is introduced after once reducing the pressure in each processing chamber or processing container to create a dense atmosphere at atmospheric pressure or higher pressure, and in the case of a solution, an atmosphere of the required concentration is created. Note that moisture is required to decompose the organoboron compounds that seep into the wood, so if the wood is particularly dry, it may be necessary to treat it after applying moisture, or to apply moisture after treatment and leave it for a long period of time. Necessary moisture can be provided by leaving it to absorb moisture from the atmosphere at high temperatures.

When the organic boron compound infiltrated into the wood is decomposed by the water contained in the wood or the water added from the outside, fine boron oxide and boric acid are generated in the wood structure.

When boric acid is heated, it decomposes at temperatures above 185°C, producing water and boron oxide, which exhibits fire resistance.Boron oxide melts at temperatures above 450°C and forms a glass-like substance that prevents wood from burning. When a fire occurs or when high heat that develops into a fire occurs, the boron oxide and boric acid inside the wood decompose and change in quality, exhibiting fire retardant and combustible properties and preventing the spread of fire in the event of a fire. ) Don't be fooled by its effective prevention (Boron monoxide also works effectively to control termites).

Next, an example will be described.

Example 1. A 50cm thick rubber tree with an equilibrium water content of 10 or more at 30°C and humidity of 1 [7016] was placed in a pressure vessel and treated with 10 kg/cm of saturated steam at 175°C for 2 hours, resulting in an equilibrium water content of 61. A heat and pressure treated wood having an anti-expansion coefficient of 40 was obtained.

Next, the rhinoceros was processed into a size of 1 cm x 50 cm x 50 cm, placed in a sealed container, and the pressure was reduced to 50 wHg. Trimethyl borate vapor was then introduced and the pressure was brought to atmospheric pressure, and the mixture was left for 60 minutes, and then taken out and left for 24 hours.

Comparative example 1. In Example 1, the rubber tree was treated in the same manner as in Example 1, except that the rubber tree was subjected to heat and pressure treatment.

Next, the treated plates of Example 1 and Comparative Example 1 were JISA 1
321, 1322, and 5801, the board of Example 1 was found to have flame retardant grade 1 and flame retardant grade 1 at 740°C for 15 minutes.
The product passed the standards for chemically treated architectural fire protection materials.

However, the board of Comparative Example 1 caught fire and burned after 740'' CIO minutes.

Claims (1)

[Claims] (1) The equilibrium moisture content (%) of the original wood is
) by 2 to 4% and the anti-swelling rate to 20 to 4%.
It is characterized by immersing heat-pressure-treated wood reduced to 60% in an atmosphere of an organic boron compound to allow this compound to penetrate inside and decompose it due to the moisture contained, producing boron oxide and boric acid within the wood structure. How to treat wood for fire protection.