JP2005112700A - Aqueous solution of boron compound stable in room temperature, manufacturing method and utilization of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for manufacturing a neutral aqueous solution containing sodium borate in high concentration and stable at room temperature by a simple method using boric acid and borax as raw materials and for forming wood, paper, cloth and non-woven fabric into a fire proof/fire resistant /incombustible material. <P>SOLUTION: The aqueous solution of the boron compound stable at room temperature contains no chelating agent or surfactant and contains ≥2.5 mol/kg in total of (x) pts. boric acid (H<SB>3</SB>BO<SB>3</SB>) and (y) pts. borax (Na<SB>2</SB>B<SB>4</SB>O<SB>7</SB>-10H<SB>2</SB>O) (where, x<35, y<40 and 0<x<(y+5)) expressed in terms of boron to 100 pts. water. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an aqueous solution of a boron compound that is stable at room temperature, a method for producing the same, and an application thereof. More specifically, the present invention relates to a fireproof / fireproof / incombustible composition containing a boron compound in a high concentration, which is suitably used for fireproofing, fireproofing and incombustibility of wood, paper, woven fabric and non-woven fabric.

Boric acid (H ₃ BO ₃ ) and borax (sodium tetraborate decahydrate, Na ₂ B ₄ O ₇ .10H ₂ O) have long been used as fireproofing agents for wood. For example, Shigehisa Ishihara, “Boron and its compounds as wood fireproofing agents”, Wood Preservation, Japan Wood Preservation Association, 1989, Vol. 15, No. 6, p. As described in detail in 248-260 (Non-patent Document 1), boron compounds have already been studied from the first half of the 19th century as combustion inhibitors for cellulose-based materials such as wood. In view of cost and availability, boric acid and borax are often studied as fireproofing agents, and these have been reported to have an effect of suppressing flaming combustion and red heat combustion of wood and wood materials.
However, as shown in Table 1, boric acid and borax have a problem that solubility in water (dissolution amount g in 100 g of water) is low.

  Although the solubility of boric acid and borax is relatively higher in hot water than in cold water, when both boric acid and borax are dissolved in water at 20 ° C., the concentration is 7 wt. It is difficult to inject into a wood or woody material as an aqueous solution in an amount sufficient to suppress wood combustion. When boric acid or borax is dissolved in hot water and poured into wood or woody materials, the operability is poor, and there is a tendency that aqueous solutions do not easily penetrate into wood at high temperatures. There are problems such as precipitation of crystals.

The sodium borate salt exhibiting the highest solubility at 20 ° C. is Na ₂ O · B ₂ O ₃ · 8H ₂ O, and its solubility is 20.0% by weight in terms of anhydrous salt. That is, an aqueous solution at room temperature containing 16.7% by weight or more in terms of anhydrous salt (2.5 mol / kg or more in terms of boron) sodium borate has not been known so far, and its preparation method is also known. There wasn't. This sodium borate salt is synthesized from naturally-occurring boric acid and borax by a solid phase reaction, but its preparation is not simple.

  In JP-A-8-73212 (Patent Document 1), 5 g of boric acid compound at room temperature is added to either an aqueous solution of a sequestering agent (chelating agent or chelating agent) or an aqueous solution of a wet permeable surfactant. A high concentration boric acid compound obtained by mixing so as to have a solubility equal to or higher than 100 g of water and hydrothermally reacting the mixture at 60 ° C. or higher is disclosed. Further, this publication describes that dissolution of boric acid and borax is considered to involve ion micelle formation and association by a chelating agent or a surfactant. However, an aqueous solution of a high concentration boron compound containing only an inorganic compound in the absence of an organic compound such as a chelating agent or a surfactant has not been known.

  On the other hand, buildings using wood bring about a calm atmosphere, and in recent years, their demand has increased. Especially for high-rise buildings and underground buildings where noncombustibility is required by the Building Standard Law, the use of timber has not been approved so far, but it has been approved by the development of noncombustible timber, and its demand has increased dramatically. ing. Under such a background, it is strongly demanded to produce an incombustible liquid containing a higher concentration of inorganic components at a lower cost by a simpler method.

JP-A-8-73212 Shigehisa Ishihara, “Boron and its compounds as wood fireproofing agents”, Wood Preservation, Japan Wood Preservation Association, 1989, Vol. 15, No. 6, p. 248-260

  The present invention uses boric acid and borax as raw materials, contains sodium borate in a high concentration, and produces a neutral aqueous solution that is stable at room temperature by a simple method to fire-proof and protect wood, paper, woven fabric and nonwoven fabric. It is an object to provide technology for making fireproof and incombustible materials.

Thus, according to the present invention, x part of boric acid (H ₃ BO ₃ ) and borax (Na ₂ B ₄ O ₇ .10H) are contained in 100 parts of water without containing a chelating agent or surfactant. ₂ O) y part (provided that x <35, y <40, 0 <x <y + 5) at least 2.5 mol / kg in terms of boron Is provided.

In addition, according to the present invention, x part of boric acid (H ₃ BO ₃ ) and y part of borax (Na ₂ B ₄ O ₇ .10H ₂ O) with respect to 100 parts of water (provided that x <35 , Y <40, 0 <x <y + 5), heated to dissolve, and then cooled to room temperature to obtain an aqueous solution of boron compound that is stable at room temperature. A manufacturing method is provided.

  Furthermore, according to the present invention, there is provided a liquid fireproof / fireproof / incombustible composition comprising the above aqueous solution.

  Further, according to the present invention, the above liquid fireproof / fireproof / incombustible composition is impregnated or sprayed onto an object selected from wood, paper, woven fabric and non-woven fabric, and 100 g or more of fireproof per kg of the object. A fireproof / fireproof / incombustible material is provided which is obtained by including a fireproof / incombustible composition in an object and then drying it.

  Furthermore, according to the present invention, there is provided a powdery fireproof / fireproof / incombustible composition obtained by evaporating and drying the aqueous solution.

  According to the present invention, boric acid and borax are used as raw materials, sodium borate is contained at a high concentration, and a neutral aqueous solution that is stable at room temperature is produced by a simple method, and wood, paper, woven fabric and nonwoven fabric are produced. Technology can be provided for fireproofing, fireproofing and nonflammable materials.

The aqueous solution of a boron compound which is stable at room temperature of the present invention does not contain a chelating agent or a surfactant with respect to 100 parts of water, and x part of boric acid (H ₃ BO ₃ ) and borax (Na _2). B ₄ O ₇ .10H ₂ O) is characterized by containing 2.5 mol / kg or more of boron in terms of boron (provided that x <35, y <40, 0 <x <y + 5).

The boric acid used in the present invention is H ₃ BO ₃ (orthoboric acid) and / or HBO ₂ (metaboric acid), and borax is sodium tetraborate decahydrate Na ₂ B ₄ O ₇ .10H ₂ O. is there. Although the weight of borax is in terms of the weight of decahydrate, borax is not necessarily a hydrate and may be an anhydride.

In the present invention, “parts” means parts by weight.
“Concentration unit: mol / kg” is the molar concentration by weight, and is expressed by the mass (mol) of boron dissolved per 1 kg of water as a solvent.
“Room temperature” means a temperature range of 15 ° C. to 25 ° C.
“Stable at room temperature” means that it does not precipitate at room temperature.

The aqueous solution of a boron compound that is stable at room temperature according to the present invention includes, for example, x part of boric acid (H ₃ BO ₃ ) and borax (Na ₂ B ₄ O ₇ .10H ₂ O) with respect to 100 parts of water. It can be prepared by adding y part (however, x <35, y <40, 0 <x <y + 5), heating to dissolve, and then cooling to room temperature. Heating is preferably performed at 70 to 90 ° C, more preferably 75 to 85 ° C.

  As conventionally known, when boric acid alone is added to water, heated and dissolved, and cooled, boric acid corresponding to the difference in solubility cannot be completely dissolved but is precipitated (recrystallized). For example, even if 20 g of boric acid is added to 100 g of water and heated to 100 ° C. and completely dissolved, if it is cooled to 20 ° C., the solubility at 20 ° C. is 4.90, so 15.1 g of boric acid is It will be deposited. The same applies to borax. Even if a large amount of borax is dissolved by heating, if it is cooled to room temperature, only the amount corresponding to the solubility at room temperature will be dissolved. ).

  The boron compound aqueous solution of the present invention, which is stable at room temperature, is prepared by mixing both boric acid and borax in water at a specific ratio, heating to completely dissolve, and then cooling to room temperature. It is based on finding out that acid, borax, etc. do not precipitate.

  For example, 20 g of boric acid and 25 g of borax were added to 100 g of water and heated, and then completely dissolved at 70 ° C. Then, when it cooled at 20 degreeC, it became transparent aqueous solution and the deposit was not seen at all. This aqueous solution is 3.48 mol / kg in terms of boron and 23% by weight in terms of solid content, and is an aqueous solution having a concentration that could not exist stably at room temperature. The aqueous solution had a pH of 6.95 and a specific gravity of 1.13.

When the Raman spectrum of the obtained aqueous solution (fireless B) was measured at room temperature, as shown in FIG. 1, fireless B (D) was a boric acid saturated aqueous solution (A), a borax saturated aqueous solution (B). A spectrum different from that of the saturated aqueous solution of boric acid / borax (C) was obtained.
According to FIG. 1, the boric acid saturated aqueous solution (A) exhibits a spectrum of borate ions (BO ₃ ³⁻ ), and the borax saturated aqueous solution (B) is tetraborate ions (B ₄ O ₇ ²⁻ ). Spectrum. Moreover, the boric acid / borax saturated aqueous solution (C) exhibits a spectrum in a state where borate ions and tetraborate ions are added together. On the other hand, the spectrum of the aqueous solution (D) of the boron compound stable at room temperature according to the present invention is shifted to a lower energy side as compared with the spectrum of the single and room temperature mixed aqueous solution, and has peaks at completely different locations (880). ± 150 cm ⁻¹ ).

Generally, as the degree of polymerization of borate ions increases and becomes large polyborate ions, the peak of the Raman spectrum is considered to shift to a lower energy side, and the aqueous solution of the boron compound of the present invention containing boron at a high concentration is Compared to tetraborate ion, it dissolves as a polyborate ion containing more boron in one anion, for example, B _{2n + 4} O _{3n + 7} ²⁻ (n is an integer of 1 or more). It is estimated that In addition, the boron atom is surrounded by three oxygen atoms, but the three boron-oxygen bonds are all on the same plane, and a polyborate ion having a high degree of polymerization is considered to be a planar anion. This is deeply related to the film forming property and foaming property described later.

  When an aqueous solution of the boron compound of the present invention was irradiated with a semiconductor-excited YAG laser (wavelength of 532 nm), a Tyndall phenomenon in which the optical path appeared to shine was observed. Also from this fact, it is considered that the aqueous solution of the boron compound of the present invention is in a state in which polyborate ions having a size of 1 to 100 nm are dissolved, which is equivalent to a colloid.

  When the aqueous solution of the boron compound of the present invention was heated and evaporated to dryness, the tendency of forming a film on the surface was observed without the foam generated during the evaporation of water being easily blown, and finally a polystyrene-like solid substance was gotten. The specific gravity of the solid was about 0.1 to 0.3, and its properties were completely different from boric acid and borax as raw materials.

The obtained solid was subjected to powder X-ray diffraction using CuKα ray (1.5418 Å). As a result, two broad diffraction peaks as shown in FIG. 2, specifically 2θ = 27.8 ± 1. Peaks were observed at .2 and 45.7 ± 1.2. This diffraction peak is not a single diffraction peak of boric acid or borax, but is considered to be a diffraction peak of amorphous sodium borate using boric acid or borax as a raw material.
From the above, what heated both boric acid and borax, melt | dissolved the quantity which cannot be melt | dissolved at room temperature, and cooled to room temperature is considered to differ from well-known sodium borate aqueous solution.

  When the boron compound aqueous solution was prepared by changing the mixing ratio of boric acid and borax, the results shown in FIG. 3 were obtained. In the figure, “◯” indicates that no precipitate is generated even when heated to 70 ° C. or higher and is cooled to room temperature, “Δ” indicates that a very small amount of precipitate is generated, and “×” indicates that a precipitate is generated. Show things. From the obtained results, it can be seen that the relationship between the boric acid x part and the borax y part relative to 100 parts of water needs to satisfy the relations x <35, y <40, and 0 <x <y + 5.

In addition, as the boric acid / borax mixing ratio increases, the pH of the solution tends to become neutral, and the boric acid / borax mixing ratio is in the range of 0.6 to 1.2. It was found that the pH of the solution can be adjusted in the range of 6-8. For example, 25 g of boric acid and 35 g of borax are added to 100 g of water, heated to 70 ° C. or higher, dissolved, and cooled to room temperature (27.2 wt%, 4.26 mol /% with respect to boron). kg) had a pH of 6.65. Making the solution liquid neutral is extremely important when used as an incombustible liquid.
Furthermore, it was found that an aqueous solution (30.2% by weight, 5.1 mol / kg with respect to boron) in which 31 g of boric acid and 38 g of borax were added to 100 g of water could be prepared.

  The boron compound aqueous solution of the present invention can also be prepared by adding excess boric acid and borax to 100 parts of water, heating to dissolve, and then cooling to room temperature to remove undissolved matter. Can be prepared. That is, as described above, boric acid and borax are added, and it may be completely dissolved without causing undissolved residue, but an excessive amount of boric acid and borax than the range shown in FIG. 3 is added, An aqueous solution of the boron compound of the present invention can also be obtained by causing undissolved residue and collecting the supernatant. However, this method is not preferable economically.

  For example, the boron compound of the present invention is obtained by adding 50 g of boric acid and 70 g of borax to 100 g of water, heating to 70 ° C. or higher, cooling to room temperature, and filtering and separating the undissolved residue. Can be obtained. When the obtained filtrate (supernatant liquid) was evaporated to dryness, a solid matter of 30% by weight was obtained. Moreover, when the undissolved residue collected on the filter paper was dried and quantified by powder X-ray diffraction using CuKα rays (1.5418Å), it was about 18 g of boric acid and about 33 g of borax. The dissolution amount obtained by subtracting the undissolved amount from the addition amount was about 32 g of boric acid and about 37 g of borax, which was almost equal to the amount that can be dissolved by the above-described complete dissolution method. Thus, even if boric acid and borax are added excessively on the assumption that undissolved residue is generated, an aqueous solution of a boron compound containing a solid content of about 30% by weight can be prepared.

The aqueous solution of the boron compound of the present invention preferably further contains phosphoric acid or a phosphate.
Phosphoric acid and phosphate have a combustion suppressing effect that increases the fire extinguishing speed after flame contact.
The amount of phosphoric acid or phosphate added is about 0.2 to 5% by weight, preferably 0.5 to 2% by weight.

According to the present invention, a liquid fireproof / fireproof / incombustible composition containing an aqueous solution of the above boron compound is impregnated or sprayed on an object selected from wood, paper, woven fabric and non-woven fabric, and per 1 kg of the object. There is provided a fireproof / fireproof / incombustible material characterized by being obtained by adding 100 g or more of a fireproof / fireproof / incombustible composition to an object and then drying it.
Since the liquid fireproof / fireproof / incombustible composition of the present invention contains a high concentration of boron compound, a large amount of fireproof / fireproof / incombustible components can be introduced into the material. Incombustible and flame retardant performance can be imparted. For materials such as wood that have a small surface area ratio relative to weight, it is preferable to use an autoclave or the like and impregnate under pressure. The impregnation is preferably performed under a pressure of 0.5 N / mm ² or more, preferably 1 N / mm ² or more.

According to the present invention, there is provided a powdery fireproof / fireproof / incombustible composition obtained by evaporating and drying an aqueous solution of the boron compound.
Evaporation to dryness can be performed by a known method, but spray drying (spray drying) is particularly preferred. The “spray drying method” is a method in which a liquid is made into a fine mist, sprayed in hot air, and instantaneously dried to obtain a powder.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

(Example 1)
An experiment in which wood is impregnated with an aqueous solution of a boron compound prepared by adding 20 parts of boric acid and 25 parts of borax to 100 parts of water at a room temperature (solid content 22.9%, hereinafter referred to as “2025 solution”). went.
As the wood, laminated timber (100 mm × 25 mm × 25 mm), south-sea wood (100 mm × 24 mm × 24 mm), cedar (100 mm × 12 mm × 30 mm), cypress (100 mm × 3 mm × 20 mm) were used. After each wood was dried at 100 ° C. for 24 hours before impregnation, the specific gravity was measured to be 0.46, 0.58, 0.31, and 0.50, respectively. When these woods were impregnated with an aqueous solution of a boron compound at 25 ° C. for 24 hours and then dried at 100 ° C. for 24 hours, the weight of each wood was 3.7%, 3.1%, 10.5%, Increased by 5%. This increase in weight is sodium borate that can be introduced into the wood.

  A simple combustion test was performed on the obtained wood using a butane gas burner. As a comparison, untreated wood was also tested in the same manner, and it was ignited by flame contact for 10 seconds. In contrast, the treated wood was observed to have a tendency to extinguish when the flame was released when the flame was released after the treated wood had been exposed to a burner flame for more than 30 seconds and no flame was produced. In addition, the flame was brought closer to the treated wood, and the phenomenon that the components of sodium borate introduced into the inside of the wood swelled as a white film and protected the wood from the flame covering the inside of the wood was observed.

The maximum amount of solids that can be introduced into the wood using conventional techniques was 10.5% by weight of cedar. In order to pass the nonflammability test based on the Building Standards Law, it is necessary to introduce at least 200 kg of inorganic solids per m ^{3 of} wood. Therefore, in the case of cedar wood having a specific gravity of 0.31, an inorganic solid content of 65% or more by weight must be introduced. However, impregnation under room temperature and normal pressure in this example was considered to have been able to impart flame retardancy from the result of the simple combustion test, although the amount introduced was just over 10% by weight.

(Example 2)
An experiment was carried out in which an aqueous solution was prepared and impregnated in the same manner as in Example 1 except that 1% by weight of phosphoric acid was further added. Using the same material as in Example 1, an experiment was performed in which wood was impregnated at room temperature.
The weight after impregnation increased by 4.6%, 3.6%, 11.8% and 4.1%, respectively. The weight increase rate is larger than that in Example 1 because phosphoric acid was introduced into the wood.
In the simple combustion test, it was observed that the fire extinguishing speed after flame contact was slightly faster than in Example 1. This is considered that the combustion suppression effect which phosphoric acid has contributed positively.

(Example 3)
When a 2025 solution prepared in the same manner as in Example 1 was impregnated into 0.30 g of Japanese paper and air-dried, the weight of the Japanese paper was 0.63 g, and an inorganic solid content of 110% by weight relative to the Japanese paper could be introduced. .
When the obtained Japanese paper was in contact with flame, it did not ignite but only carbonized. The weight after carbonization was 0.46 g.
When the Japanese paper was impregnated with the 2025 solution, changes in the texture such as the hand of the Japanese paper becoming hard were observed. Therefore, the inorganic solid content was introduced by spraying the 2025 solution onto 0.40 g of the Japanese paper using a spray bottle and air-drying. did. As a result, the weight of the Japanese paper was 0.68 g, and an inorganic solid content of 70% by weight with respect to the Japanese paper could be introduced.
When the obtained Japanese paper was in contact with flame, it did not ignite but only carbonized. The weight after carbonization was 0.46 g.

Example 4
The test was conducted in the same manner as in Example 3 except that thick bran paper used for bran was used instead of Japanese paper.
When inorganic solids were introduced into 0.55 g of bran paper by the impregnation method and the spray method using a spray, the weight of the bran paper was 1.20 g and 0.88 g, respectively, and 118% by weight, respectively. And 60 wt% inorganic solids could be introduced.
When the obtained bran paper was in contact with flame, no flame was produced and only carbonization occurred. The weight after carbonization was 0.90 g and 0.58 g, respectively.
It has been found that the aqueous solution of the boron compound of the present invention is extremely effective for incombustibility of paper used for buildings and is effective for fire prevention.

(Example 5)
The test was conducted in the same manner as in Example 3 except that 100% cotton curtain cloth was used instead of Japanese paper.
When an inorganic solid content was introduced into 10.8 g of curtain fabric by the impregnation method, the weight of the curtain fabric was 15.6 g, and 44.4 wt% of the inorganic solid content could be introduced. In addition, when the degree of impregnation and the presence or absence of squeezing after the impregnation were changed, the inorganic solid content could be introduced in the range of 20 to 105% by weight.
When all the curtain fabrics obtained were in contact with flame, it was observed that there was a tendency for the fire to extinguish when the flame was released.
In many cases, the curtain is ignited to cause a fire accident. By impregnating the aqueous solution of the boron compound of the present invention, a cotton cloth having an excellent effect on fire prevention can be obtained.

(Example 6)
The test was conducted in the same manner as in Example 5 except that a 100% polyester curtain fabric was used instead of the 100% cotton curtain fabric.
When the degree of impregnation of the 2025 solution, the presence or absence of squeezing after the impregnation, and the like were changed, the inorganic solid content could be introduced in the range of 12 to 88% by weight.
As a comparison, when the flame was contacted with an untreated curtain cloth, it was observed that the melt of the polyester dropped as a drop and further ignited and the flame soared. On the other hand, the treated curtain cloth fell in the form of a polyester melt, but hardly ignited the drop or cloth and only carbonized black. In addition, it was observed that the fire extinguished immediately when the flame was covered with a white film deposited on the surface of the melt.
It has been found that the aqueous solution of the boron compound of the present invention generally exhibits a remarkable flame retardant effect even for synthetic chemical fibers that are difficult to flame retardant.

(Example 7)
The test was conducted in the same manner as in Example 6 except that a 100% polyester carpet and a 100% polyester non-woven fabric for a ventilation fan filter were used in place of the 100% polyester curtain fabric.
When the degree of impregnation of the 2025 solution, the presence or absence of squeezing after the impregnation, etc. were changed, inorganic solid content could be introduced in the range of 15 to 90% by weight, almost the same as the result of 100% polyester curtain cloth. Matched.
When the obtained carpet and nonwoven fabric were in flame contact, the melt of the polyester was temporarily ignited and the flame rose, but it was confirmed that it immediately extinguishes in a form covered with white inorganic matter. did it.
It turned out that the aqueous solution of the boron compound of this invention can provide a flame-retardant effect to the cloth comprised by polyester fiber regardless of a use and a form.

(Example 8)
Waste wood chips (20-30 mm × 5 mm × 0.5-1 mm or so) used as a raw material for particleboard were impregnated with 2025 solution to check for combustibility.
The waste wood chips were impregnated with the 2025 solution for 1 minute at room temperature and normal pressure, and dried. As a result, an inorganic solid content of 25 to 35% by weight ratio could be introduced into the waste wood chip. The inorganic solid content of the waste wood chip is larger than the solid content of 10.5% of the cedar wood of Example 1. This is presumably because the waste wood chips are small and the surface area is large, so that the liquid can easily penetrate into the inside.
Each piece of waste wood chip was burned with a burner flame, and the state of ignition was examined, but it was only carbonized, extinguished when the flame was released, and never ignited.
From the obtained results, it is understood that a non-combustible particle board can be produced using waste wood chips incombustible with a 2025 solution as a raw material.

Example 9
Using an autoclave, an experiment was conducted in which the 2025 solution was poured into wood under pressure.
The injection conditions were a pressure of 2 N / mm ² (20 kgf / cm ² ), a temperature of 20 ° C. and 70 ° C.
As the wood, cedar wood dried at a temperature of 100 ° C. for 1 week was used for each condition. Under the condition of a temperature of 20 ° C., the matured wood A (specific gravity of 0.343), the matured wood B (specific gravity of 0.385) and the thinned wood A (specific gravity of 0.299) are used. 0.357) and thinned wood B (specific gravity 0.307) were used.

FIG. 4 shows the relationship between the impregnation time of the 2025 solution and the amount introduced (inorganic solid content kg / m ³ per unit volume). When compared at the injection temperature, the introduction amount is higher at 70 ° C. until about 12 hours after impregnation, and the amount of introduction is reversed after 24 hours, and the final introduction amount is higher at 20 ° C. This shows that the higher the temperature, the faster the injection rate, but the smaller the amount introduced in the final equilibrium state.
From the obtained results, in order to introduce a large amount of inorganic components into the wood, it is desirable to impregnate at room temperature rather than high temperature, and therefore an aqueous solution in which a large amount of inorganic components are stably dissolved at room temperature is required. I understand.

The amount of the material impregnated at 20 ° C. for about 24 hours is in the range of 230 to 270 kg / m ³ , and judging from the amount of introduction, it is predicted that the incombustible test based on the Building Standard Law will be passed. On the other hand, impregnation at 70 ° C. and finally introduction amount of 197 kg / m ³ is considered to be in the borderline of pass / fail of the nonflammability test.
In addition, since the inorganic component permeates into the inside through the wood conduit, the injection rate tends to be higher when the ratio of the cut surface of the conduit to the surface is larger. It is presumed that this is due to the difference in the injection rate between the matured material A and the matured material B.

(Example 10)
The test was performed in the same manner as in Example 9 except that instead of the 2025 solution, a 2025 solution containing 1% by weight of phosphoric acid prepared in the same manner as in Example 2 was used.
The injection conditions were a pressure of 2 N / mm ² and a temperature of 20 ° C.
As wood, cedar wood, mature wood D (specific gravity 0.351) and thinned wood C (specific gravity 0.313) dried at a temperature of 100 ° C. for 1 week were used.
Without opening the autoclave in the course, it was impregnated with the solution continuously for 48 hours, the final introduction amount became ^{265kg / m 3, 261kg / m} 3 respectively.
From the results obtained, it can be seen that the presence of phosphoric acid does not adversely affect the injection of inorganic components.

(Example 11)
A test was conducted in the same manner as in Example 9 except that cypress wood (specific gravity 0.37) and red pine wood (specific gravity 0.48) were used instead of cedar wood.
The injection conditions were a pressure of 2 N / mm ² and a temperature of 20 ° C.
Without opening the autoclave in the course, it was impregnated with the solution continuously for 48 hours, the final introduction amount became ^{210kg / m 3, 255kg / m} 3 respectively. Judging from the amount of these timbers, it can be seen that they are at a level that passes the nonflammability test.

(Example 12)
In order to receive non-combustibility certification based on the Building Standard Law, it is necessary to pass either a non-flammability test or a combustion test. The non-flammability test is a test to check the weight reduction rate by holding a cylindrical piece of wood with a diameter of 40 mm and a height of 55 mm in an electric furnace at 750 ° C. for 20 minutes. The weight reduction rate is 30% or less. Is a necessary condition.
In Examples 9 to 11, non-flammability tests were performed using wood impregnated with an aqueous solution of the boron compound of the present invention. When the wood pieces were inserted into an electric furnace previously maintained at 750 ° C., all the wood pieces were in a red-hot state, but the temperature rise of the electric furnace after insertion remained within 12 ° C. After 20 minutes, the wood piece taken out from the electric furnace and allowed to cool was a black charcoal solid, maintaining the shape of the wood piece. The weight reduction rate is: matured wood A: 23.1%, matured wood B: 25.9%, thinned wood A: 21.2%, mature wood C: 28.2%, thinned wood B: 29.1%, Mature wood D: 21.8%, thinned wood C: 19.5%, cypress wood: 26.0%, red pine wood: 26.9%. As described above, the weight reduction rate of the wood impregnated with the aqueous solution of the boron compound of the present invention was all within 30%, which satisfied the judgment standard of the nonflammability test.

(Example 13)
482 kg of a 2025 solution prepared in the same manner as in Example 1 was granulated by the spray drying method under the following conditions.
Apparatus: Nippon Chemical Machinery Manufacturing Co., Ltd. Nozzle diameter: 0.84 mm
Swirl: SC
Spray pressure: about 120 kgf / cm ² (12 mPa)
Spray amount: about 120L / H
Hot air volume: 40 Nm ³ / min.
Hot air temperature: 160 ° C
Exhaust air temperature: 79.8-83.8 ° C. (cone portion)
75.8-80.2 ° C (Cyclone part)

Clean spherical particles having the following physical property values were obtained (powder recovery amount 64.2 kg).
Water content: 7.2% (105 ° C. × 2 hours loss on drying value)
Particle size: 30-50 μm (measured from electron micrograph)
Average particle size: 41.7 μm
Bulk specific gravity: 0.87 (touch specific gravity)
0.61 (apparent specific gravity)
Thus, the aqueous solution of the boron compound of the present invention could be granulated by a known method.

It is a figure which shows the result of the Raman spectrum of the boric-acid saturated aqueous solution (A), the borax saturated aqueous solution (B), the boric-acid / borax saturated aqueous solution (C), and the aqueous solution (D) of the boron compound of this invention. It is a figure which shows the result of the powder X-ray diffraction of the solid substance obtained from the aqueous solution of the boron compound of this invention. It is a figure which shows the range which boric acid and borax completely dissolve. It is a figure which shows the relationship between an impregnation time and the introduction amount when the aqueous solution of the boron compound of this invention is impregnated to wood.

Claims (11)

The x part of boric acid (H ₃ BO ₃ ) and the y part of borax (Na ₂ B ₄ O ₇ .10H ₂ O) (without the chelating agent or surfactant) , X <35, y <40, 0 <x <y + 5), which is 2.5 mol / kg or more in terms of boron, and is an aqueous solution of a boron compound stable at room temperature. The aqueous solution according to claim 1, wherein the aqueous solution of the boron compound has a peak at 880 ± 150 cm ⁻¹ in the Raman spectrum.   A powder obtained by evaporating and drying an aqueous solution of a boron compound has peaks at 2θ = 27.8 ± 1.2 and 45.7 ± 1.2 in powder X-ray diffraction (CuKα ray 1.5418４) Item 3. The aqueous solution according to Item 1 or 2.   The aqueous solution according to claim 1, further comprising phosphoric acid or phosphate. 100 parts of water, x part of boric acid (H ₃ BO ₃ ) and y part of borax (Na ₂ B ₄ O ₇ .10H ₂ O), where x <35, y <40, 0 <x <Y + 5) is added, dissolved by heating, and then cooled to room temperature to obtain an aqueous solution of a boron compound that is stable at room temperature.   The production method according to claim 5, wherein the heating is performed at 70 to 90 ° C.   A liquid fireproof / fireproof / incombustible composition comprising the aqueous solution according to claim 1.   The liquid fireproof / fireproof / incombustible composition according to claim 7 is impregnated or sprayed on an object selected from wood, paper, woven fabric and non-woven fabric, and 100 g or more of fireproof / fireproof / incombustible material per kg of the object. A fireproof / fireproof / incombustible material obtained by including a composition in an object and then drying the composition. The fireproof / fireproof / incombustible material according to claim 8, wherein the impregnation is performed under a pressure of 0.5 N / mm ² or more.   A powdery fireproof / fireproof / incombustible composition obtained by evaporating and drying the aqueous solution according to any one of claims 1 to 4.   The powdery fireproof / fireproof / incombustible composition according to claim 10, wherein the evaporation to dryness is performed by a spray drying method.

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