JP2583174B2 - Improved wood fiber board and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved wood fiber board made of wood fibers subjected to non-combustibility treatment and a method for producing the same.

[0002]

2. Description of the Related Art A technique of dispersing and fixing a nonflammable inorganic compound in cell pores inherent in wood in the form of a wood rod, board or veneer to make it flame-retardant has been known (Japanese Patent Laid-Open No. 61-244502).
However, in this known technique, it is necessary to disperse a nonflammable inorganic compound in wood in a wood rod, board or veneer state by 40% or more based on the absolute dry weight of wood. In order to satisfy this requirement, it has to be immersed in a nonflammable inorganic compound solution for a long time, depending on the size of the cross-sectional shape. Further, even when the wood is immersed for a long time, the outer periphery of the wood is largely impregnated, but it is difficult to uniformly disperse the wood to the inside. Further, since the powdery nonflammable inorganic compound adheres to the outer peripheral portion of the wood and impairs the cosmetic property, it cannot be provided as a product as it is, and it is necessary to remove it by means such as washing with water. However, it is uneconomical because it is difficult to recover the removed incombustible inorganic compound, and there is a problem that a waste liquid treatment step is required.

In view of such a problem, the present applicant has
By impregnating wood fibers with the first liquid and the second liquid,
The water-insoluble incombustible inorganic compound produced by these reactions is filled or adhered or adhered to the cell pores and / or the inner wall surface of the cell pores of the wood fibers, and the wood fibers are bonded and integrated to form a non-combustible fiber board. (Japanese Patent Laid-Open No. 3-27199). According to this technique, the non-combustible treatment can be performed within a relatively short time, the non-combustible inorganic compound can be dispersed and fixed substantially uniformly over the entire fiberboard, and the cosmetic property is impaired. Operational effects such as no occurrence can be obtained.

[0004]

The present applicant has conducted further experiments on the non-combustible fiberboard according to the above-mentioned proposal, and as a result,
If this fiberboard is to be burned in a fire test or the like, although an excellent effect on flame retardancy is recognized,
It was found that a large amount of smoke was generated. Therefore, the first
When the dewatering and washing treatment was performed after the reaction treatment of the liquid and the second liquid, smoke generation was considerably suppressed, but flame retardancy was significantly reduced.

Although the reason for this is not necessarily clear, it is practically difficult to completely react the first solution and the second solution.
When a chloride aqueous solution such as gCl ₂ or CaCl ₂ is used,
It is presumed that chloro ions remain as unreacted components, which contribute to the improvement of flame retardancy, but have an adverse effect on smoke prevention.

[0006]

Accordingly, the present invention further improves the above-mentioned prior art by the present applicant to prevent unreacted components remaining in the wood fiber after the reaction treatment with the first and second liquids. It is an object of the present invention to provide a fiberboard which has both a flame retardancy and a smoke resistance as well as a water-insoluble incombustible inorganic compound produced by impregnating a first liquid and a second liquid. , Phosphate and borate are filled or adhered or fixed to the cell pore and / or the inner wall of the cell pore,
Further, the improved wood fiber board is characterized in that wood fibers adhered or fixed to the fiber surface are molded and integrated via an adhesive substance.

Another object of the present invention is to provide a method for producing the above-mentioned improved wood fiberboard,
The wood-fiber having cell pores is impregnated with a first liquid, and then impregnated with a second liquid that is mixed and reacted with the first liquid to produce a water-insoluble incombustible inorganic compound, thereby producing the water-insoluble substance. The non-combustible inorganic compound is filled or adhered to or adhered to the inside of the cell pore and / or the inner wall of the cell pore of the wood fiber, and the wood fiber is washed with water, and the wood fiber further contains a mixture of phosphate and borate. A method for producing an improved wood fiber board, characterized by impregnating with three liquids and molding and integrating the wood fibers thus obtained via an adhesive substance.

The wood fibers used are, for example, softwood such as pine, cedar and cypress or hardwood such as lauan, kapole, chestnut and poplar as chips, which are defibrated according to a conventional method to obtain a water content of 20% or less. Preferably, it is dried to 10% or less. This wood fiber has a length of 1 to 30 mm and a diameter of 2 to 3
Most of them are about 00μ. The wood fiber has a shape in which conduits, temporary conduits, or cells are bundled, and the cell wall around the fiber is often torn or cracked.

The first liquid and the second liquid are allowed to react with each other in the pores of the cell holes and conduit holes of the dried wood fiber to form and fill the water-insoluble incombustible inorganic compound, The first step of the non-combustible treatment is carried out by fixing or adhering the non-combustible inorganic compound in a layered manner along the line and further fixing or adhering the non-combustible inorganic compound to the outer periphery of the wood fiber. This first stage non-combustible treatment can be performed by the following steps.

That is, the wood fibers are sufficiently immersed in an aqueous solution (first liquid) of a water-soluble inorganic salt for impregnation. On this occasion,
By impregnating under reduced pressure or pressure, the impregnation of the wood fiber can be performed more effectively. Further, the wood fiber is brought into a high water content state without drying, or once dried, immersed in water or warm water and absorbed to make it saturated, then immersed in the first liquid to diffuse and impregnate it. Is also good.

As the first liquid, MgCl ₂ , MgB
r ₂ , MgSO ₄ .H ₂ O, Mg (NO ₃ ) ₂ .6H ₂
O, CaCl ₂ , CaBr ₂ , Ca (NO ₃ ) ₂ , Ba
An aqueous solution of an alkaline earth metal salt such as Cl ₂ .2H ₂ O, BaBr ₂ , Ba (NO ₃ ) ₂ , or AlCl ₃ , AlB
_{r 3, Al 2 (SO 4} ) 3, Al (NO 3) 3 · 9H 2
An aqueous solution of a metal salt such as O or ZnCl ₂ is exemplified.

Next, the first liquid is removed to remove the excess first liquid.
Performs liquid removal processing. The liquid removal treatment is performed by, for example, centrifugal liquid removal. By removing an excessive amount of the first liquid, it is possible to suppress the excessive generation of the nonflammable inorganic compound in the outer peripheral portion of the wood fiber, and to improve the diffusion and impregnation of the aqueous solution to be subsequently impregnated.

Next, a compound liquid (second liquid) which reacts with the first liquid to form a water-insoluble incombustible inorganic compound is added to the wood fiber using a blender, a spray, or the like, and mixed or immersed in the wood fiber. The second liquid is impregnated into wood fibers.

As the second liquid, (NH ₄ ) ₂ C
O ₃ , (NH ₄ ) ₂ SO ₄ , (NH ₄ ) ₂ HPO ₄ ,
Examples thereof include ammonium salts such as (NH ₄ ) H ₂ PO ₄ and NH ₄ BO ₂ .

[0015] By the application and impregnation of the second liquid, the first liquid and the second liquid react in the wood fiber to produce a water-insoluble incombustible inorganic compound. As the non-combustible inorganic compound generated,
Magnesium phosphate, calcium phosphate, barium phosphate, aluminum phosphate, magnesium borate, magnesium carbonate, calcium carbonate, zinc phosphate, barium carbonate, calcium nitrate, calcium compound such as barium nitrate, magnesium compound, aluminum compound, barium compound, Zinc compounds and the like are exemplified. After the reaction, the second liquid is subjected to a liquid removal treatment.

Since the resulting incombustible inorganic compound is insoluble in water, it is filled, adhered or adhered to the inside of the cell pore of the wood fiber, the inner wall of the cell pore, and the outer periphery of the wood fiber after drying. As a result, even when a crack or a crack is included in the cell wall at the outer periphery of the wood fiber, the nonflammable inorganic compound is present in such a manner as to block or fill the cell wall.

The non-combustible inorganic compound is preferably mixed at a rate of 33% by weight or more based on the wood fiber.
Below this, sufficient fire protection performance cannot be obtained. Further, in order to increase the reaction efficiency between the first liquid and the second liquid, the second liquid
The addition and mixing of the liquid is performed under a heating atmosphere, preferably at least 40 ° C.
More preferably, it is performed at a temperature of 50 ° C. or higher.

In the first stage of the non-combustible treatment,
The processing order of the first liquid and the second liquid is not limited, and the second liquid may be impregnated first.

The thus obtained wood fibers filled with, or adhered to or adhered to, the water-insoluble incombustible inorganic compound in the cell pores, the inner wall of the cell pores and the outer periphery of the fibers, are washed with water to remove excess non-combustible materials. The first liquid and the second liquid remaining in an unreacted state are removed while removing the inorganic compounds. For example, when BaCl ₂ and (NH ₄ ) ₂ HPO ₄ are used as the first liquid and the second liquid, Ba ₂ is used as a water-insoluble incombustible inorganic compound.
(PO ₄ ) ₂ and BaHPO ₄ are produced, and chloro ion (C
l ⁻ ) and ammonium ions (NH ⁺ ) remain, but the chlor ions are removed by dewatering and washing, and the smoke prevention effect is improved.

Next, as a second step of non-combustibility treatment, an aqueous solution (third solution) of a mixture of phosphate and borate is further impregnated. As the phosphate in the third liquid, an ammonium salt is preferable. For example, (NH ₄ ) H ₂ PO ₄ , (NH ₄ )
₂ HPO ₄ , (NH ₄ ) ₃ PO _4, etc. are exemplified. As the borate, metaborate such as KBO ₂ , NaBO ₂ (NH ₄ ) BO ₂ , LiB ₄ O ₇ , K ₂ B ₄ O ₇ , Na ₂ B
₄ O _7, tetraborate salts such as _{(NH 4) 2 B 4 O} 7, (NH
₄ ) A pentaborate such as B ₅ O ₈ is exemplified.

By further impregnating the third liquid, which is an aqueous solution of these mixtures, the inorganic compounds in the first liquid remaining in the wood fibers in an unreacted state even after dewatering and washing are completely reacted. Let it. Since phosphate and borate coexist in the third liquid, part of the first liquid remaining in the wood fiber in an unreacted state reacts with phosphate, and the other reacts with borate. However, due to the combined effect of these reactions, substantially all of the first liquid can be reacted, and the unreacted state can be prevented.

At the same time, the phosphate and borate in the third liquid are impregnated or attached to the wood fibers as they are,
It greatly contributes to the improvement of flame retardancy.

After the impregnation of the third liquid, the surplus third liquid is removed. After the deliquoring treatment, it is dried to have a water content of 25% or less, preferably 7 to 15%. Thus, the water-insoluble incombustible inorganic compound, phosphate and borate are filled or adhered or fixed to the inside of the cell pore or the inner wall of the cell pore and the outer periphery of the fiber, and the fire retardant compound is impregnated in the wood fiber and the outer periphery thereof. A non-combustible wood fiber in an attached state is obtained.

The non-combustible wood fiber is put into a mixing apparatus, and a urea resin adhesive, a phenol resin adhesive, a melamine resin adhesive, an epoxy resin adhesive, an isocyanate / vinyl acetate resin adhesive is used. And a modified synthetic resin adhesive and a sizing agent. In order to further improve the fire protection performance of the obtained wood fiber board, an adhesive containing a fire protection compound can be used.

[0025] The non-combustible wood fiber to which the adhesive is added and mixed is blown and fed into a forming device to form a continuous wood fiber mat having a constant thickness on a conveying device. After cutting the wood fiber mat to a fixed size, the wood fiber mat is inserted into a hot press and hot-pressed to obtain the improved wood fiber board of the present invention.

[0026]

【Example】

<Example 1> Radiator pine chips were heated at 160 ° C for 7 minutes.
The mixture was boiled at kg / cm ² for 5 minutes to perform degreasing and softening treatment. The chips were defibrated by a defibrator type refiner, and the obtained wood fibers were dried.

The wood fiber was immersed in a 17% by weight aqueous barium chloride solution (first liquid) at 50 ° C. for 1 hour, subjected to diffusion treatment, and then drained. This was dried with hot air to adjust the water content to 7%. The wood fiber is charged into a blender, and a 28% by weight aqueous solution of diammonium hydrogen phosphate (second liquid) is added and mixed, and water-insoluble phosphoric acid is added to pores such as cell pores of the wood fiber or the outer periphery of the wood fiber. After a non-combustible inorganic compound composed of barium and barium hydrogen phosphate was formed, the liquid was removed and washed with water.

Further, the wood fiber was charged into a blender, and a mixed aqueous solution (third liquid) of 28% by weight of diammonium hydrogen phosphate and 3.8% by weight of sodium tetraborate was added and mixed.

Thereafter, the water content was adjusted to 6% by hot air drying. The weight increase rate of the wood fiber by this non-combustible treatment is 88.
%Met.

The obtained non-combustible wood fiber was mixed in a mixer by spraying 4.5% by weight of wax with respect to the wood fiber. Then, in another mixer, 10% by weight of a phenolic resin adhesive was added to and mixed with the wood fiber.

This wood fiber is put into a duct and blown,
It was dropped and deposited on a screen conveyor by a forming apparatus to form a wood fiber mat.

After cutting the wood fiber mat to a predetermined size, the wood fiber mat was put into a hot press and hot-pressed at 200 ° C. for 2 minutes to obtain an improved wood fiber board of the present invention. <Comparative Example 1> Radiator pine chips were heated at 160 ° C for 7 minutes.
The mixture was boiled at kg / cm ² for 5 minutes to perform degreasing and softening treatment. The chips were defibrated by a defibrator type refiner, and the obtained wood fibers were dried.

The wood fibers were immersed in a 17% by weight aqueous barium chloride solution (first liquid) at 50 ° C. for 1 hour, subjected to diffusion treatment, and then drained. This was dried with hot air to adjust the water content to 7%. The wood fiber is charged into a blender, and a 28% by weight aqueous solution of diammonium hydrogen phosphate (second liquid) is added and mixed, and water-insoluble phosphoric acid is added to pores such as cell pores of the wood fiber or the outer periphery of the wood fiber. After a non-combustible inorganic compound composed of barium and barium hydrogen phosphate was formed, the liquid was removed and washed with water. A mixed aqueous solution of diammonium hydrogen phosphate and sodium tetraborate (third liquid) was immediately added to the wood fiber without mixing, and the mixture was immediately charged into a mixer, and a wood fiber board was obtained in the same manner as in the following examples. Was.

Table 1 shows the results of a fire prevention test performed using the wood fiber boards obtained in Example 1 and Comparative Example 1.

[Table 1]

According to the present invention, a wood fiber board excellent in fire prevention performance and smoke suppression performance can be obtained.

Claims (2)

(57) [Claims] 1. A water-insoluble, non-flammable inorganic compound produced by an impregnation reaction between a first liquid and a second liquid;
Phosphate and borate are filled or adhered or adhered to the cell pore and / or the inner wall surface of the cell pore, and the wood fiber adhered or adhered to the fiber surface is molded and integrated via an adhesive substance. An improved wood fiber board characterized by being made. 2. A wood fiber having cell pores is impregnated with a first liquid, and then impregnated with a second liquid that is mixed and reacted with the first liquid to produce a water-insoluble incombustible inorganic compound. The resulting water-insoluble incombustible inorganic compound is filled or adhered to or adhered to the inside of the cell pore and / or the inner wall of the cell pore of the wood fiber, and after washing with dewatered water, phosphate and borate are further added to the wood fiber. A method for producing an improved wood fiber board, comprising impregnating a third liquid containing the mixture of the above, and forming and integrating the wood fibers thus obtained via an adhesive substance.