JP2646158B2 - Manufacturing method of composite board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently producing a composite board used as a building material or a furniture member having excellent fire protection performance.

[0002]

2. Description of the Related Art Generally, sawn timber, plywood, laminated veneer (LV)
Wooden boards referred to as L, LVB) are used for various purposes as architectural and furniture members, after the surfaces of the wooden boards are appropriately processed such as painting and paper covering.

In recent years, it has been required to improve the fire prevention performance of these wooden boards, and various proposals have been made for this purpose. For example, a method of laminating a wood veneer and a metal plate to form a composite plate (Japanese Patent Publication No. 53-39) or dispersing and fixing a nonflammable inorganic compound in cell-specific pores of a wood in a plate or veneer state. There is known a method of making it flame-retardant (JP-A-61-244502).

[0004]

However, since these composite wooden boards have a certain fiber direction, expansion and contraction occur due to the absorption and release of water, and the expansion rate particularly in the direction perpendicular to the fiber direction is increased. It has a problem that it is large and lacks dimensional stability, and further, it is necessary to apply a base treatment such as an acid treatment to the metal surface when performing surface coating, paper covering, or the like.

[0005] Further, in the method of making a wooden board a flame-retardant in a board or veneer state, in order to impregnate and disperse a nonflammable inorganic compound in an amount of 40% or more with respect to the absolute dry weight of wood, the size of the cross-sectional shape must be increased. Although depending on the conditions, the wood board needs to be immersed in the solution in which the nonflammable inorganic compound is dissolved for a long time, and the efficiency is low. Further, a large amount of the nonflammable inorganic compound is impregnated on the front and back surfaces of the wooden board and the peripheral portion near the wood opening, and it is extremely difficult to sufficiently and uniformly disperse and fix the inside even after soaking for a long time. After being immersed in the non-flammable inorganic compound solution, the powdery non-flammable inorganic compound adhering to the outer periphery of the wooden board is washed away with water, and the non-flammable inorganic compound thus removed is collected and re-used. Since it is difficult to use, it has many problems such as being uneconomical and requiring a waste liquid treatment step.

[0006]

In view of the above situation,
The present inventor has conducted intensive studies to provide a building plate having excellent fire protection performance and excellent dimensional stability, and as a result, completed the present invention.

That is, the present inventor focused on the excellent dimensional stability of a wood fiber board or a wood chip board formed integrally from wood fiber or wood chip obtained from waste wood, and made a plurality of wood fiber boards. And / or by laminating and compounding wood chipboard and metal foil to obtain a composite board having excellent fire protection performance, a plurality of wood fiber boards / woodchipboard and metal foil are alternately arranged. An attempt was made to bond by heating and pressing via an adhesive, but a puncture phenomenon caused by moisture in the plate material occurred during the heating and pressing, and the desired composite plate could not be obtained.

The puncture phenomenon will be further described below by taking a wood fiber board as an example. First, apply an adhesive to the wood fibers obtained by defibrating the chips and dry them.
This wood fiber is deposited and matted to form a wood fiber board by heat molding. After the wood fiber board is cured until it reaches the equilibrium moisture content by absorbing moisture in the atmosphere by performing humidity control on the wood fiber board, the surface is sanded and cut to a fixed size. Since the moisture content of the wood fiber board obtained by heating and pressing is very low and close to a completely dry state, if the moisture conditioning curing is performed as it is, sanding processing and cutting processing are performed. Since the fiberboard absorbs moisture to cause warpage due to expansion, this is performed for the purpose of preventing this. Since the wood fiber board thus obtained contains water up to the equilibrium moisture content, when a plurality of such wood fiber boards are laminated and heated and pressed via an adhesive, the water in the board material evaporates. Then, it was found that a force to go outside was generated, and a puncture was generated due to the release of water vapor when the pressure was released. This phenomenon is the same when a wood chipboard is used.

Therefore, the present inventor used a wood mat layer obtained by adding a thermosetting resin adhesive to wood fibers / wood chips and temporarily pressing the wood fibers / wood chips instead of the wood fiber board / wood chip board. The present inventors have conceived of laminating the wood mat layers and the metal foil layers alternately, and then heating and pressing to integrally form the adhesive, and have arrived at the present invention.

That is, according to the present invention, a wood mat layer obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and temporarily pressing them, and a metal foil layer are alternately arranged on the front and back. A method for producing a composite board, comprising laminating a wooden mat layer so as to be arranged thereon, and then heating and pressing to form an integrated adhesive.

As schematically shown in FIG. 1, the composite plate manufactured according to the present invention has a sandwich structure in which wood mat layers 1a and 1b are respectively laminated and bonded to the front and back sides of a metal foil layer 2. In the configuration example of FIG. 1, the wood mat layers 1a and 1b on the front side and the back side have substantially the same thickness,
Although the metal foil layer 2 is disposed substantially at the center in the thickness direction of the entire composite board, as shown in FIG. 2, the metal mat layer 1a on the front side is made thinner than the wood mat layer 1b on the rear side. You may comprise so that the foil layer 2 may be arrange | positioned near the surface of a composite board. In addition, the wood mats 1a, 1
b may be both wood fiber mats or both wood chip mats, or the surface layer 1a may be a wood fiber mat and the back layer 1b may be a wood chip mat, or vice versa. May be. These combinations are arbitrarily selected according to the use of the composite board. The numbers of the wood mat layers and the metal foil layers are not limited, and a structure in which a plurality of metal foil layers and a plurality of wood mat layers are alternately laminated and the wood mat layers are arranged on the front and back surfaces. There may be. Due to the above-mentioned variable factors, composite plates having various constitutions can be obtained according to the intended use, even if they have the same thickness.

[0012] In the production method of the present invention, wood fibers obtained by cutting hardwood such as Rawan, Kapole, chestnut and poplar or softwood such as pine, cedar and cypress into chips and then defibrating according to a conventional method. Alternatively, wood chips obtained by cutting and crushing small-diameter wood, sawn wood, wood cores, wood chips and the like are used as raw materials.

[0013] A urea resin-based adhesive, a phenol resin-based adhesive, a melamine resin-based adhesive, an epoxy resin-based adhesive, a polyisocyanate resin-based adhesive, or a composite resin adhesive thereof is applied to the obtained wood fiber or wood chip. And the like. The addition amount of these thermosetting resin adhesives is preferably 10 to 20% by weight based on wood fibers or wood chips, and the resin ratio is preferably 30 to 60%. The adhesive can be uniformly mixed with the wood fiber when the resin ratio is low.

The metal foil layer is made of a metal or an alloy such as iron, aluminum, stainless steel or copper and has a thickness of 20 to 10 mm.
A 0μ metal foil is preferably used. The surface of this metal foil is subjected to rust prevention treatment such as plating if necessary. Further, a metal foil provided with a plurality of fine holes in a mesh shape or a metal woven fabric woven using metal threads can be used as the metal foil layer in the present invention. In this way, by using a metal foil having air permeability by micropores or the like, moisture remaining in the wood fiber or wood chip added with the adhesive is dried to escape to the outside during heating and pressing. The puncturing phenomenon that occurs at the time of decompression can be effectively prevented, since the movement of the pressure is not restricted.

The step of producing a composite board according to the method of the present invention will be described in more detail by taking wood fiber mats as an example. The softwood or hardwood chips are steamed under high-temperature and high-pressure steam to perform a degreasing softening treatment. After that, the fibers are defibrated by a defibrating device to obtain wood fibers. Most of the wood fibers have a length of 1 to 30 mm and a thickness of about 2 to 300 μm, and several to several tens of cell holes consisting of wood cells and conduit holes or temporary conduit holes are formed. Since the cell wall around the fiber is often torn or cracked, it absorbs a lot of moisture and moisture.

After the obtained wood fiber is dried by a drying device, it is put into a mixing device, and the thermosetting resin adhesive is added and mixed. In the mixing device, optional additives such as a sizing agent, a water generating agent, a smoke reducing agent and the like can be simultaneously mixed as needed.

The wood fibers to which the thermosetting resin adhesive has been applied are then dried while being blown and transported in a hot air duct.
The blowing speed at this time is adjusted in a wide range depending on the specific gravity of the wood fiber, the feeding amount, the processing capacity of the preceding and following steps, and the like, but is generally about 15 to 20 m / sec. The wood fibers are dried to a moisture content of about 6 to 15% by blowing with the hot air.

The dried wood fiber is put into a forming apparatus, dropped on a conveyor, the wood fiber is deposited and laminated, and then temporarily pressed to obtain a wood fiber mat which can be handled. After cutting the wood fiber mat into an appropriate size, the wood fiber mat is alternately arranged with the metal foil, laminated so that the wood fiber mat is arranged on the front and back, and further heated and pressed to obtain a target composite board. When laminating a wood fiber mat and a metal foil, bonding the composite board by applying a thermosetting resin adhesive similar to the adhesive added to and mixed with the wood fiber on the front and back surfaces of the metal foil in advance Strength can be further improved.

When the composite board manufactured according to the present invention is used in a situation where a high level of fire protection performance is required, at least the wood fiber or wood chip is used to obtain the wood mat layer 1a disposed on the surface side. Is preferably subjected to a fire prevention treatment in advance. This fire prevention treatment is performed, for example, by using a void portion and / or an inner wall surface of a cell hole of the wood fiber or wood chip before the thermosetting resin adhesive is added, and / or the wood fiber or wood chip. This is a treatment for filling, adhering, or fixing an incombustible inorganic compound to the outer peripheral portion of the above. The treatment will be described in detail below using a wood fiber as an example.

That is, before the thermosetting resin adhesive is added, and immediately after being appropriately dried in a drying apparatus, the wood fibers are placed in an aqueous solution of a water-soluble inorganic salt (hereinafter, referred to as "first liquid"). Impregnate by fully immersing. At this time, it is effective to forcibly accelerate the impregnation by applying reduced pressure or increased pressure. Further, the wood fiber is made to have a high water content state without drying, or after being dried, immersed in water or warm water to absorb water and made it saturated, and then immersed in the first liquid for diffusion and impregnation. Is also good. The first liquid is MgC
_{l 2, MgBr 2, MgSO 4} · H 2 O, Mg (N
_{O 3) 2 · 6H 2 O} , AlCl 3, AlBr 3, Al 2
_{(SO 4) 3, Al (} NO 3) 3 · 9H 2 O, CaCl
₂ , CaBr ₂ , Ca (NO ₃ ) ₂ , ZnCl ₂ , Ba
Aqueous solutions such as Br ₂ , BaCl ₂ .2H ₂ O, and Ba (NO ₃ ) ₂ are exemplified. By immersing and impregnating the wood fiber in the first liquid, the ions of the solute inorganic salt diffuse into the cell pores of the wood fiber by diffusion.

Next, in order to remove the excess first liquid, a liquid removing process is performed. The liquid removal treatment is performed by, for example, centrifugal liquid removal or showering, or washing with a soak in water, and the like. By removing an excessive amount of the first liquid, it is possible to confirm that excessive inflammable inorganic compounds are generated on the surface of the wood fiber. Control and improve the diffusion and impregnation of the aqueous solution to be subsequently impregnated. Further, it is possible to prevent the generation of the nonflammable inorganic compound in a free state that is not attached or fixed to the wood fiber. After the liquid removal treatment, the component crystals of the first liquid deposited on the surface are removed as necessary.

Next, a compound liquid which reacts with the first liquid to form a water-insoluble incombustible inorganic compound (hereinafter referred to as “second liquid”)
Liquid) is added to the wood fiber using a blender, spray or the like and mixed or immersed in the wood fiber.
The liquid is impregnated into the wood fibers. As in the case of the first liquid, the impregnation of the second fiber with the wood fibers can be promoted by the decompression or pressure treatment. As the second liquid, Na ₂
CO ₃ , H ₂ SO ₄ , (NH ₄ ) ₂ CO ₃ , Na ₂ SO
₄ , (NH ₄ ) ₂ SO ₄ , H ₂ PO ₄ , Na ₂ HP
O ₄ , (NH ₄ ) ₂ HPO ₄ , H ₃ BO ₃ , NaB
O ₂ and NH ₄ BO ₂ are exemplified. By applying or dipping the second liquid, the second liquid is diffused and impregnated into the cell pores of the wood fiber, and the first liquid and the second liquid react in the wood fiber to generate a nonflammable inorganic compound. . Examples of the generated nonflammable inorganic compounds include calcium compounds such as magnesium phosphate, calcium phosphate, barium phosphate, aluminum phosphate, magnesium borate, magnesium carbonate, calcium carbonate, zinc phosphate, barium carbonate, calcium nitrate, and barium nitrate. , Magnesium compounds, aluminum compounds, barium compounds, lead compounds, zinc compounds, silicate compounds and the like. For example, when barium chloride is used as the first liquid and ammonium hydrogen phosphate is used as the second liquid, barium cation and phosphoric acid anion react to form barium phosphate and barium hydrogen phosphate. Is done.

After the completion of the reaction, the excess second liquid is removed by dewatering by means of centrifugal dewatering or washing with water such as showering or soaking in water. The immersion treatment and the liquid removal treatment of the second liquid may be repeatedly performed as necessary. After the dewatering treatment, it is dried to have a water content of 25% or less, preferably 7 to
15%. Since this incombustible inorganic compound is water-insoluble, it is filled or adhered or adhered to the inside of the cell pore or the inner wall of the cell pore of the wood fiber after drying, and also adhered or fixed to the outer periphery of the wood fiber. As a result, the non-combustible inorganic compound is present in a form that blocks or fills voids and cracks that appear on the surface of the wood fiber.

The non-combustible inorganic compound has a content of 3
It is preferable to be mixed at a ratio of 3% by weight or more, and if it is less than 3%, sufficient fire protection performance cannot be obtained. Further, in order to increase the reaction efficiency of the first liquid and the second liquid, the addition and mixing of the second liquid is preferably performed in a heated atmosphere, particularly at a temperature of 40 ° C. or higher, more preferably 50 ° C. or higher. If the first liquid and the second liquid are in a warm water state and wood fibers are immersed therein, or when the first liquid and the second liquid are immersed, electric or mechanical vibration is given by ultrasonic waves or a vibrator. Diffusion and reaction of the treatment liquid into the wood fibers are favorably performed. The order of treatment with the first liquid and the second liquid does not matter, and the treatment with the second liquid may be performed first.

Thus, a non-combustible inorganic compound is fixed to the inside of the cell pore or the inner wall surface of the wooden fiber and the non-combustible inorganic compound is fixed or adhered also to the outer peripheral portion thereof to obtain a fire-resistant wood fiber. The fire-treated wood fiber is introduced into the mixing device as described above, and the thermosetting resin adhesive is added and mixed.

The fire prevention treatment for the wood fibers or wood chips may be performed by a method other than the above-described method. For example, substances conventionally known as fire retardants, for example, ammonium salts such as ammonium phosphate, ammonium sulfate and ammonium bromide, alkali metal salts such as potassium carbonate, sodium carbonate and potassium phosphate, and alkali salts such as calcium chloride and magnesium chloride It can also be carried out by immersing and impregnating wood fibers or wood chips in a solution of an earth metal salt, a metal compound such as aluminum chloride, aluminum sulfate or the like, followed by drying.

[0027]

【Example】

Example 1 A radiator pine chip was heated at 160 ° C. and 7 kg / cm ^2.
For 5 minutes to perform a degreasing softening treatment. The chips were defibrated with a defibrator refiner, and the obtained wood fibers were dried. This wood fiber was immersed in a 30% barium chloride aqueous solution for 10 minutes, subjected to diffusion treatment, and then drained. This was dried with hot air to adjust its water content to 7%. This wood fiber is charged into a blender device and ammonium phosphate 40
% Aqueous solution is added and mixed to form a non-flammable inorganic compound composed of water-insoluble barium phosphate and barium hydrogen phosphate in pores such as cell pores of the wood fiber and on the outer periphery of the wood fiber. It was dried with hot air to adjust its water content to 6%. Weight increase rate of wood fiber by this fire prevention treatment is 40%
Met.

The wood fiber subjected to the fire protection treatment is charged into a blender, and 4% of the wood fiber content in the blender is calculated based on the amount of the wood fiber.
After adding and mixing the wax sizing agent and a 10% phenol resin adhesive, the mixture was conveyed to a forming apparatus, dropped on a screen conveyor and deposited.

The wood fibers thus deposited were cut into a suitable length, inserted into a hot press and preheated to obtain a fire-treated wood fiber mat.

Using the three wood fiber mats thus obtained and two 45 μm-thick iron foils, wood fiber mat / iron foil / wood fiber mat / iron foil / wood fiber mat from the front side. After laminating in order, insert in hot press to 20
Hot pressed at 0 ° C for 5 minutes, thickness 13mm, specific gravity 0.6
5 was obtained.

When a heating test was performed on this composite plate, it was confirmed that the composite plate exhibited a fire-preventing performance that passed the semi-incombustible material.

Example 2 A radiata pine log or a waste material was charged into a flaker to obtain a flake-shaped wood chip. After drying the wood chips, the wood chips were sorted to collect suitable flake-shaped wood chips. This wood chip was fire-treated in the same manner as in the case of the wood fiber of Example 1, and then charged into a continuous mixer. In the mixer, 1% of a wax sizing agent and 8% of phenol were added to the wood chip amount. After adding and mixing the resin adhesive, it was conveyed to a forming device, dropped on a screen conveyor and deposited.

After cutting the accumulated wood chips to an appropriate length, the wood chips were inserted into a hot press and pre-pressed to obtain a fire-treated wood chip mat.

Using the three wood chip mats thus obtained and two 45 μm thick iron foils, wood chip mat / iron foil / wood chip mat / iron foil / wood cutting from the front side After lamination in the order of one mat, insert in hot press and
Then, a composite plate having a thickness of 13 mm and a specific gravity of 0.5 was obtained.

When a heating test was performed on this composite plate, it was confirmed that the composite plate exhibited a fire-prevention performance that passed the semi-incombustible material.

Example 3 The fire-resistant wood fiber mat obtained in Example 1 and Example 2
Using the fire-protected wood chip mat obtained in the above and a 45 μm iron foil, laminating in the order of wood fiber mat / iron foil / wood chip mat / iron foil / wood fiber mat from the front side, and inserting it into a hot press Hot pressing at 200 ° C for 5 minutes
A composite plate having a thickness of 3 mm and a specific gravity of 0.60 was obtained.

When a heating test was performed on this composite plate, it was confirmed that the composite plate exhibited a fire-proofing performance that passed the semi-incombustible material.

[0038]

According to the method of the present invention, a wood mat which can be handled by temporarily pressing using wood fibers or wood chips in a state where an adhesive is applied and dried is used. Since it is formed by hot pressing after lamination with a metal foil, the working efficiency is excellent, and no puncture is generated even when the pressure is released after hot pressing. Therefore, it is possible to efficiently manufacture a composite plate having excellent dimensional stability and improved fire prevention performance.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of the configuration of a composite plate manufactured by the method of the present invention.

FIG. 2 is a perspective view showing another configuration example of the composite board manufactured by the method of the present invention.

[Explanation of symbols]

 1a Wood mat layer 1b Wood mat layer 2 Metal foil layer

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location B32B 31/00 7148-4F B32B 31/00 // B29L 31:10

Claims (4)

(57) [Claims] 1. A wood mat layer obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and preliminarily pressing, and a metal foil layer are alternately arranged, and the wood mat layers are arranged on the front and back. And heating and pressing to form an integrated bond. 2. The method for manufacturing a composite board according to claim 1, wherein a thermosetting resin adhesive is applied to the front and back surfaces of the metal foil layer, and then laminated with the wood mat. 3. The method according to claim 1, wherein a metal foil having a plurality of fine holes is used as the metal foil layer. 4. The method for producing a composite board according to claim 1, wherein the wood fiber or the wood chip is subjected to a fire protection treatment in advance.