JPH0351104A - Manufacture of flame-retarded - Google Patents

Abstract

PURPOSE:To facilitate the infiltration of water soluble inorganic salt, and improve the water resistance by replacing the inside air of a heat-pressurized lumber with carbon dioxide, and pregnating it with an aqueous solution of water soluble inorganic composition producing a water-insoluble incombustible inorganic composition in reaction with the carbon dioxide. CONSTITUTION:The absolute value of equilibrium moisture content of an original lumber is lowered by 2 - 4% through a heat-pressurizing operation and the inside air of a heat-pressurized lumber which is made by 20 - 60% in its anti-expansion rate is replaced with carbon dioxide, and further it is impregnated with an aqueous solution of water soluble inorganic composition producing water insoluble incombustible inorganic composition in reaction with carbon dioxide, and thus the incombustible inorganic composition is dispersed and fixed in the structure of the lumber. Accordingly, the hemicellulose in the lumber elutes and the dimensional alterating rate becomes less. Moreover, it has been a porous structure, and therefore an pregnation rate of carbon dioxide and water soluble inorganic composition as well as a dispersing and fixing rate of the incombustible inorganic composition become large. Thus, since the water insoluble composition is fixed in the intracellular pores, it never elutes by immersion in water. As a result, a stable flames-retardant property can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a method for producing flame-retardant wood useful for collecting materials and furniture materials.

<Prior art> As a method of imparting combustibility (self-extinguishing in the sense that it decomposes thermally but does not combust with flame) to wood, water-soluble inorganic salts, such as secondary There is a method of impregnating wood with ammonium phosphate, monoammonium phosphate, potassium carbonate, sodium carbonate, calcium chloride, potassium carbonate, sodium carbonate, calcium chloride, magnesium chloride, zinc chloride, etc., singly or in combination. Since it is a water-soluble drug, there are problems with water resistance, and its uses are limited, such as being unable to be used as an exterior material. Therefore, there is a method of dispersing a water-insoluble inorganic compound in a liquid, immersing the wood in this treatment solution, and impregnating the inorganic compound with the liquid to the inner pores of the wood's cells. The pores are very small and impregnation is difficult.

<Purpose of the invention> The purpose of the present invention is to modify the cell structure of wood.

An object of the present invention is to provide a method for producing flame retardant wood that facilitates the penetration of the water-soluble inorganic salt and has excellent water resistance. The air inside the heat-pressure treated wood, which has lowered the absolute value of the equilibrium moisture content (%) by 2 to 496 points and increased the anti-swelling rate by 20 to 60 points, is replaced with carbon dioxide, which reacts with the carbon dioxide and turns into water. This is a method for producing flame-retardant wood in which the non-flammable inorganic compound is dispersed and fixed within the structure of the wood by impregnating the wood with an aqueous solution of a water-soluble inorganic compound that produces a flammable inorganic compound.

Here, the anti-expansion chamber is A 8 E (Anti-8
wellingEfficiency) using the following formula.

Do: Expansion coefficient of untreated material D: Expansion coefficient of treated material The heating and pressurizing operation in the present invention includes heating with an electric heater, gas heater, oil heater, etc. in a pressure vessel, pressurization with a compressor, or Although heating and pressurizing using steam is possible, heating and pressurizing using steam is safe and economical. The heating and pressurizing conditions are 120
~250℃, 2~40~/d, processing time varies depending on temperature and pressure, but for example, in the case of a 50mm thick plate made of rubber, 120℃, 2kg/d for 8 hours, or 210℃
After treatment at 120 degrees Celsius for 30 minutes, the absolute value of the equilibrium moisture content becomes about 2 degrees lower and the anti-swelling coefficient becomes about 20 inches. Further, when treated at 150° C. and 5 kyial for 16 hours or at 250° C. and 4 ky 7 ci for 2 hours, the equilibrium moisture content is lowered by about 41 and the anti-swelling coefficient is increased by about 60 factors.

Note that 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, it is dangerous because high heat is required for operation, and the natural texture of the wood will be lost. , carbonization is significant and mechanical strength is significantly deteriorated, which is undesirable.

Wood treated with heat and pressure in this way has a slow decline in weight of about 10% due to the elution of hemlock cellulose with a high equilibrium moisture content in the wood, and the change in equilibrium moisture content due to environmental changes is significantly reduced. As a result, the rate of dimensional change is reduced. In addition, the number of voids increases by the amount of hemicellulose eluted, resulting in a porous structure, so in the first step of replacing the air inside the wood with carbon dioxide, and by reacting with carbon dioxide, a non-flammable inorganic material that is insoluble in water is used. The step of impregnating an aqueous solution of a water-soluble inorganic metal compound that produces a compound and the step of dispersing and fixing the nonflammable inorganic compound into the structure of the wood become easier and the amount of fixing increases. As a method for replacing the air inside treated wood with carbon dioxide, for example, the wood is placed in a container that can be depressurized and pressurized, and after reducing the pressure inside the container, carbon dioxide is inserted into the container a predetermined number of times. You can gain by repeating.

Next, in order to impregnate a water-soluble inorganic compound that reacts with carbon dioxide to produce a non-flammable inorganic compound that is insoluble in water, for example, the wood is immersed in the aqueous solution, and if necessary, pressure impregnation is performed. This can be done by Then, water VC-insoluble, non-flammable inorganic compounds are generated and dispersed in the intracellular pores. Examples of the water-insoluble, non-flammable inorganic compounds that are generated include calcium carbonate, aluminum carbonate, and the like.

Applicable water-soluble inorganic compounds include, for example, calcium bromide, calcium iodide, calcium chloride, calcium carbonate, calcium nitrate, calcium nitrite, calcium ammonium sulfate, calcium acetate, sodium aluminate, calcium aluminate, potassium alionate. and other salts. One type of these compounds may be used alone, a plurality of types of compounds may be mixed, or they may be used separately.

<Effects of the Invention> In the present invention, the heat and pressure treatment as described above causes the t-cellulose in the wood to elute, reducing the dimensional change rate.
Since it has a porous structure, a large amount of nonflammable inorganic compounds are dispersed and fixed during the entire impregnation process of carbon dioxide and water-soluble inorganic compounds. Therefore, since water-insoluble compounds are fixed in the intracellular pores, they do not elute even when immersed in water.
Stable flame retardancy can be obtained.

Next, an example will be explained.

Example 1 A 50-fin thick rubber with an equilibrium water content of 10 at 30°C and a humidity of over 70 was placed in a pressure vessel and treated with 10 ky/d saturated steam at 175°C for 2 hours. 7, and a heat-pressure treated wood with an anti-expansion coefficient of 40 was obtained.

Next, the treated wood is processed into a veneer of 1 standard thickness, placed in a container that can be depressurized and pressurized, and after the inside of the container is depressurized, carbon dioxide is filled in the container, which is repeated 3 to 4 times to create a veneer. The air inside was replaced with carbon dioxide.

Next, a saturated calcium chloride aqueous solution was poured into the container and reacted for 24 hours, resulting in a 2 weight increase of 78 pounds (bone dry method).

Comparative Example 1 The same method as in Example 1 was used except that the rubber veneer was not subjected to heat and pressure treatment, but the weight increase group was 70.

Claims (1)

[Claims] By heating and pressurizing, the absolute value of the equilibrium moisture content (%) of the original wood is lowered by 2 to 4%, and the anti-swelling rate is reduced by 20 to 60%.
By replacing the air inside the heated and pressure-treated wood with carbon dioxide and impregnating it with an aqueous solution of a water-soluble inorganic compound that reacts with carbon dioxide to produce a nonflammable inorganic compound that is insoluble in water, the structure of the wood is improved. A method for producing flame-retardant wood, characterized in that the non-flammable inorganic compound is dispersed and fixed within the wood.