JPH04351502A - Improved wooden fiber-plate and its manufacture - Google Patents

Abstract

PURPOSE:To obtain the wooden fiber plate excellent in fire retordance and little smoke generation. CONSTITUTION:Wooden fiber is impregnated and reacted with the first liquid and second liquid, whereby incombustible inorganic compound is generated, and then it is impregnated with the mixed aqueous solution of alkali metal salt and ammonium salt. Consequently, the wooden fiber in which the cell-holes are fitted with water-insoluble incombustible inorganic compound, alkali metallic salt and ammonium salt or said materials stick or firmly attach onto the inner wall-surface or the outer periphery of the cell-hole, is obtained. The incombustibly-treated wooden fiber is integrally formed through adhesive material, thereby obtaining an improved wooden fiber-plate.

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 using wood fibers treated to make it incombustible and a method for manufacturing the same.

0002

[Prior Art] A technique for making wood sticks, boards, or veneers flame retardant by dispersing and fixing nonflammable inorganic compounds in the cell pores inherent in the wood has been known (Japanese Patent Laid-Open No. 61-244502
However, in this known technology, it is necessary to disperse a nonflammable inorganic compound in the wood in the form of a stick, board, or veneer in an amount of 40% or more based on the absolute dry weight of the wood. In order to meet this requirement, it was necessary to immerse the material in a nonflammable inorganic compound solution for a long time, depending on the size of the cross-sectional shape. Further, even if the wood is immersed for a long time, although the outer periphery of the wood is impregnated with a large amount, it is difficult to uniformly disperse the wood into the inside. Furthermore, powdered nonflammable inorganic compounds adhere to the outer periphery of the wood and impede its cosmetic properties, so it cannot be used as a product as it is, and it is necessary to remove it by washing with water or other means. However, it is difficult and uneconomical to recover the removed nonflammable inorganic compounds, and it also requires a waste liquid treatment process.

[0003] In view of these problems, the applicant has
By impregnating the wood fiber with the first liquid and the second liquid,
A water-insoluble, nonflammable inorganic compound produced by these reactions is filled in, adhered to, or fixed to the cell pores of the wood fibers and/or to the inner wall surface of the cell pores, and the wood fibers are adhesively molded and integrated to form a noncombustible fiberboard. We have previously proposed a technique to obtain this (Japanese Patent Application Laid-Open No. 3-27199). According to this technology, the nonflammability treatment can be performed within a relatively short period of time, the nonflammable inorganic compound can be dispersed and fixed almost uniformly over the entire fiberboard, and the noncombustible inorganic compound can be fixed almost uniformly throughout the fiberboard. It is possible to achieve effects such as no problem.

0004

[Problem to be Solved by the Invention] As a result of further experiments on the noncombustible fiberboard according to the above-mentioned proposal, the present applicant found that
When this fiberboard was tried to be burned in a fire protection test, it was found that although it had an excellent flame retardant effect, it produced a large amount of smoke. Therefore, when a deliquid washing process was performed after the reaction treatment of the first liquid and the second liquid, smoke generation was considerably suppressed, but on the other hand, the flame retardance was significantly reduced.

Although the reason for this is not necessarily clear, it is actually difficult to completely carry out the reaction between the first liquid and the second liquid.
When using a chloride aqueous solution such as gCl2, CaCl2,
Chlorine ions remain as unreacted components, and although this contributes to improving flame retardancy, it is presumed to have an adverse effect on smoke resistance.

[0006]

[Means for Solving the Problems] Therefore, the present invention further improves the prior art proposed by the present applicant and solves the problem of unreacted components remaining in the wood fibers after the reaction treatment with the first liquid and the second liquid. The purpose of this invention is to provide a fiberboard that has flame retardant properties as well as smoke-proof properties. , an alkali metal salt, and an ammonium salt,
This is an improved wood fiber board characterized in that wood fibers filled in, attached to, or fixed to the cell pores and/or to the inner wall surface of the cell pores are integrally molded via an adhesive substance.

[0007] The present invention also provides a method for producing the improved wood fiberboard described above,
The water-insoluble inorganic compound produced by impregnating a wood fiber having cell pores with a first liquid and then impregnating it with a second liquid that mixes and reacts with the first liquid to produce a water-insoluble nonflammable inorganic compound. A nonflammable inorganic compound is filled in, attached to, or fixed to the inside of the cell pores and/or to the inner wall surface of the cell pores, and after dehydrating and washing with water, the wood fiber further contains a mixture of an alkali metal salt and an ammonium salt. This is a method for producing an improved wood fiberboard, characterized by impregnating it with a third liquid and molding and integrating the wood fibers thus obtained through an adhesive substance.

[0008] The wood fibers used are, for example, chips of softwood such as pine, cedar, and cypress, or hardwood such as lauan, capor, chestnut, and poplar, which are then defibrated in accordance with a conventional method, and have a moisture 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 thickness of 2 to 3 mm in diameter.
The majority are about 00μ. This wood fiber is shaped like a bundle of conduits, tracheids, or cells, and the cell walls at the outer periphery of the fibers are often torn or cracked.

By reacting the first liquid and the second liquid in the voids of the cell pores and conduit pores of this dried wood fiber, a water-insoluble, nonflammable inorganic compound is generated and filled, or the inner wall of the cell pore is The first stage of nonflammability treatment is performed by fixing or adhering the nonflammable inorganic compound in a layered manner along the wood fibers, and further fixing or adhering the noncombustible inorganic compound to the outer periphery of the wood fiber. This first stage of nonflammability treatment can be performed by the following steps.

That is, wood fibers are treated with an aqueous solution of a water-soluble inorganic salt (
(1st liquid) for impregnation. At this time, the wood fibers can be impregnated more effectively by impregnating under reduced pressure or increased pressure. Alternatively, the wood fibers may be made into a high water content state without drying, or once dried, immersed in water or hot water to absorb water to make it saturated, and then immersed in the first liquid for diffusion impregnation. Also good.

[0011] As the first liquid, MgCl2, MgBr2
, MgSO4・H2O, Mg(NO3)2・6H2O,
CaCl2, CaBr2, Ca(NO3)2, BaCl
Aqueous solution of alkaline earth metal salt such as 2.2H2O, BaBr2, Ba(NO3)2, or AlCl3, AlBr3
, Al2(SO4)3, Al(NO3)3・9H2O,
An example is an aqueous solution of a metal salt such as ZnCl2.

[0012] Next, in order to remove the excess first liquid,
Perform the liquid removal process. The liquid removal treatment is performed by, for example, centrifugal liquid removal, showering, soaking in water, or other water washing means. By removing the excess first liquid, excessive production of nonflammable inorganic compounds at the outer periphery of the wood fibers is suppressed, and diffusion and impregnation of the aqueous solution to be impregnated next is improved.

[0013] Next, a compound liquid (second liquid) that reacts with the first liquid to produce a water-insoluble, nonflammable inorganic compound is added to the wood fibers using a blender, a sprayer, etc., and mixed or immersed. Wood fibers are impregnated with the second liquid.

As this second liquid, (NH4)2CO3
, (NH4)2SO4, (NH4)2HPO4, (NH
4) Examples include ammonium salts such as H2PO4 and NH4BO2.

[0015] By applying and impregnating the second liquid, the first liquid and the second liquid react in the wood fiber, and a water-insoluble, nonflammable inorganic compound is produced. The nonflammable inorganic compounds produced are:
Calcium compounds, magnesium compounds, aluminum compounds, barium compounds such as magnesium phosphate, calcium phosphate, barium phosphate, aluminum phosphate, magnesium borate, magnesium carbonate, calcium carbonate, zinc phosphate, barium carbonate, calcium nitrate, barium nitrate, Examples include zinc compounds. After the reaction is completed, the second liquid is subjected to a deliquid treatment.

Since the produced nonflammable inorganic compound is water-insoluble, after drying, it is filled in, attached to, or fixed in the cell pores of the wood fiber or on the inner wall of the cell pore and the outer periphery of the wood fiber. As a result, even if the cell walls of the outer periphery of the wood fibers contain fissures or fissures, the nonflammable inorganic compound is present in a form that blocks or fills them.

[0017] This nonflammable inorganic compound is preferably mixed in at a proportion of 33% by weight or more based on the wood fibers,
If it is less than this, sufficient fire protection performance cannot be obtained. In addition, 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 carried out under a heated atmosphere, preferably at 40°C or higher.
More preferably, it is carried out at a temperature of 50°C or higher.

[0018] In the first stage of nonflammability treatment,
The processing order of the first liquid and the second liquid is not limited, and the second liquid may be impregnated first.

[0019] The thus obtained wood fibers, in which the cell pores or the inner walls of the cell pores and the outer periphery of the fibers are filled with, adhered to, or fixed with a water-insoluble nonflammable inorganic compound, are dehydrated and washed with water to remove excess noncombustible material. In addition to removing the organic inorganic compounds, the first liquid and the second liquid remaining in an unreacted state are also removed. For example, when BaCl2 and (NH4)2HPO4 are used as the first and second liquids, Ba2 is used as a water-insoluble nonflammable inorganic compound.
(PO4)2 and BaHPO4 are generated, and chloride ions (Cl-
) and ammonium ions (NH+) remain, but chlorine ions are removed by dehydration and washing, improving the smoke prevention effect.

Next, as the second stage of nonflammability treatment, an aqueous solution (third stage) of a mixture of alkali metal salt and ammonium salt is
further impregnated with liquid). The alkali metal salts in the third liquid include Na2CO3, Na2SO4, Na2HPO4, N
Examples include aBO2, K2CO3, K3PO4, etc., and ammonium salts include (NH4)2CO3, (NH4)2
SO4, (NH4)2HPO4, (NH4)H2PO4
, NH4BO2, etc. are exemplified.

[0021] By further impregnating the wood fiber with the third liquid, which is an aqueous solution of these mixtures, the inorganic compounds in the first liquid that remain in the wood fibers in an unreacted state even after dewatering and washing are completely reacted. let Since ammonium salt and alkali metal salt coexist in the third liquid, part of the first liquid remaining in the wood fiber in an unreacted state reacts with the ammonium salt, and the other part reacts with the alkali metal salt. However, due to the combined effect of these reactions, substantially all of the first liquid can be reacted, and it is possible to prevent the first liquid from remaining in an unreacted state. Even when chlorides of alkaline earth metals, aluminum, zinc, etc. are used as the first liquid, residual chloride ions, which are thought to be the cause of smoke, react with the alkali metal salts and form NaCl.
Since stable chlorides such as 2 or KCl2 are produced, the smoke prevention effect can be significantly improved.

At the same time, the alkali metal salt and ammonium salt in the third liquid are impregnated or attached to the wood fibers as they are, and greatly contribute to improving flame retardancy.

After impregnation with the third liquid, the excess third liquid is removed. After the liquid removal treatment, it is dried to a moisture content of 25% or less, preferably 7 to 15%. In this way, water-insoluble, nonflammable inorganic compounds, alkali metal salts, and ammonium salts are filled, adhered, or fixed in the cell pores or on the inner walls of the cell pores and the outer periphery of the fibers, and furthermore, the wood fibers and the outer periphery thereof are impregnated with fireproof compounds. A non-flammable treated wood fiber is obtained in an attached state.

This non-combustible wood fiber is put into a mixing device and mixed with urea resin adhesive, phenol resin adhesive, melamine resin adhesive, epoxy resin adhesive, isocyanate/vinyl acetate resin adhesive. or these modified synthetic resin adhesives, and a sizing agent are added and mixed. In order to further improve the fire retardant performance of the resulting wood fiberboard, it is also possible to use an adhesive containing a fire retardant compound.

[0025] The nonflammable wood fibers mixed with an adhesive are blown by air and put into a forming device to form a continuous wood fiber mat of a constant thickness on the conveying device. The improved wood fiber board of the present invention can be obtained by cutting this wood fiber mat into regular lengths, inserting it into a hot press, and subjecting it to hot pressure molding.

[0026]

【Example】

<Example 1> Radiata pine chips at 160°C, 7
Degreasing and softening were performed by boiling at kg/cm2 for 5 minutes. The chips were defibrated using a defibrator type refiner, and the resulting wood fibers were dried.

[0027] This wood fiber was immersed in a 40% by weight aqueous barium chloride solution (first liquid) at 50°C for 1 hour, subjected to a diffusion treatment, and then drained. This was dried with hot air to adjust the moisture content to 7%. This wood fiber is put into a blender device, a 40% by weight aqueous solution of diammonium phosphate (second liquid) is added and mixed, and water-insoluble phosphoric acid is added to the cell pores of the wood fiber or the outer periphery of the wood fiber. After producing a nonflammable inorganic compound consisting of barium and barium hydrogen phosphate, it was dehydrated and washed with water.

Further, this wood fiber was put into a blender, and an aqueous mixed solution (third liquid) of 27% by weight of diammonium phosphate and 50% by weight of sodium dihydrogen phosphate was added and mixed.

After that, the moisture content was adjusted to 6% by hot air drying. The weight increase rate of wood fiber due to this nonflammability treatment is 90
%Met.

The resulting nonflammable treated wood fibers were placed in a mixer and mixed with 4.5% by weight of wax based on the wood fibers by spraying. Next, in a separate mixer, 10% by weight of a phenolic resin adhesive was added and mixed with respect to the wood fibers.

[0031] This wood fiber is put into a duct and blown by air,
A wood fiber mat was formed by falling and depositing it on a screen conveyor using a forming device.

[0032] After cutting this wood fiber mat into a predetermined size, it was placed in 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> Radiata pine chips at 160℃, 7
Degreasing and softening were performed by boiling at kg/cm2 for 5 minutes. The chips were defibrated using a defibrator type refiner, and the resulting wood fibers were dried.

[0033] This wood fiber was immersed in a 40% by weight aqueous barium chloride solution (first liquid) at 50°C for 1 hour, subjected to a diffusion treatment, and then drained. This was dried with hot air to adjust the moisture content to 7%. This wood fiber is put into a blender device, a 40% by weight aqueous solution of diammonium phosphate (second liquid) is added and mixed, and water-insoluble phosphoric acid is added to the cell pores of the wood fiber or the outer periphery of the wood fiber. After producing a nonflammable inorganic compound consisting of barium and barium hydrogen phosphate, it was dehydrated and washed with water. To this wood fiber, a mixed aqueous solution of diammonium phosphate and sodium dihydrogen phosphate (third liquid) was added and immediately put into a mixer without mixing, and the wood fiber board was prepared in the same manner as in the example below. I got it. <Comparative Example 2> Radiata pine chips at 160℃, 7
Degreasing and softening were performed by boiling at kg/cm2 for 5 minutes. The chips were defibrated using a defibrator type refiner, and the resulting wood fibers were dried.

Without impregnating this wood fiber with the first and second liquids, it is immediately put into a blender and mixed with a mixed aqueous solution of 27% by weight of diammonium phosphate and 50% by weight of sodium hydrogen phosphate (the third liquid). ) is added and mixed,
The moisture content was adjusted to 6% by hot air drying, and a wood fiberboard was obtained in the same manner as in Example 1.

Table 1 shows the results of fire protection tests conducted using the wood fiberboards obtained in Example 1 and Comparative Examples 1 and 2.

[Table 1]

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

Claims (2)

[Claims] Claim 1: A water-insoluble nonflammable inorganic compound, an alkali metal salt, and an ammonium salt produced by an impregnation reaction between a first liquid and a second liquid are present in the cell pore and/or inside the cell pore. An improved wood fiber board characterized in that wood fibers filled with, attached to, or fixed to a wall surface are integrally molded via an adhesive substance. Claim 2: Wood fibers having cell pores have a first
The wood fibers are impregnated with a second liquid that reacts with the first liquid to form a water-insoluble non-flammable inorganic compound. After filling, adhering to, or fixing to the inside of the cell pore and/or the inner wall surface of the cell pore, and removing liquid and washing with water, the wood fiber is further impregnated with a third liquid containing a mixture of an alkali metal salt and an ammonium salt, and thus obtained. A method for producing an improved wood fiberboard, characterized by integrally molding wood fibers through an adhesive substance.