JPH04216044A - Manufacture of composite panel - Google Patents

Abstract

PURPOSE:To obtain a composite panel excellent in fire resistant properties by allowing wooden fibers or wood chips to which a thermosetting resin adhesive is added to fall on a conveyor after drying and alternately laminating the formed wooden accumulated layers on the conveyor and a metal foil layer so that the wooden accumulated layers are arranged on the surface and rear of the metal foil and pressing and bonding the obtained laminate under heating to integrally mold the same. CONSTITUTION:A composite panel has a sandwich structure wherein wooden fiber layers and/or wood chip layers 1a, 1b are respectively laminated and bonded to the surfaces and rears of metal foil layers 2. Wooden fibers to which a thermosetting resin adhesive is added are dried to be charged in forming apparatuses and allowed to fall on a conveyor to form a wooden fiber accumulated layer. Metal foil rolls 20a, 20b supplying metal foils are respectively arranged between the forming apparatuses 10a, 10b, 10c and a laminate 12 wherein the wooden fiber accumulated layers and the metal foils are alternately laminated is formed and cut into an appropriate dimension by a cutter 14 to form a cut-to-size laminate 16 which is, in turn, charged in a hot press 18 to be pressed and bonded under heating to be integrally molded.

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 having excellent fireproof performance and used as a building material or furniture member.

0002

[Prior art] Generally, sawn timber, plywood, veneer laminate (LVL)
, LVB) is coated on its surface as appropriate.
After being processed such as papering, it is used for a wide variety of purposes as construction and furniture components.

[0003] In recent years, there has been a demand for improvements in the fireproof performance of these wood boards, and various proposals have been made for this purpose. For example, a method of laminating a wood veneer and a metal plate to make a composite board (Japanese Patent Publication No. 1983-39), or dispersing and fixing a nonflammable inorganic compound into the cell pores of wood in the form of a board or veneer. A method of making the material flame retardant (Japanese Unexamined Patent Publication No. 61-244502) is known.

0004

[Problems to be Solved by the Invention] However, since these composite wood boards have a fixed fiber direction, expansion and contraction occur due to absorption and release of moisture, and the expansion coefficient in the direction perpendicular to the fiber direction is particularly low. The metal surface becomes large and lacks dimensional stability, and furthermore, it is necessary to perform base treatment such as acid treatment on the metal surface when processing the surface, such as painting or papering.

[0005] In addition, in the method of making wood boards flame retardant in the form of a board or a veneer, in order to impregnate and disperse a nonflammable inorganic compound in an amount of 40% or more based on the absolute dry weight of the wood, the size of the cross-sectional shape must be adjusted. However, it was necessary to immerse the wooden board in a solution containing a nonflammable inorganic compound for a long time, which was inefficient. In addition, nonflammable inorganic compounds are impregnated in large quantities on the front and back surfaces of the wood board and in the peripheral area near the end of the wood board, so even if it is immersed for a long time,
It was extremely difficult to sufficiently and uniformly disperse and fix the particles inside. After being immersed in a nonflammable inorganic compound solution, the powdery nonflammable inorganic compounds that adhere to the outer periphery of the wood board are washed away with water. Since it is difficult to utilize, it is uneconomical and has many problems, such as requiring a waste liquid treatment process.

[0006]

[Means to solve the problem] In view of the current situation,
The present inventor has completed the present invention as a result of extensive research in order to provide a construction board with excellent fire protection performance and excellent dimensional stability.

That is, the present inventor focused on the excellent dimensional stability of wood fiberboard or wood chip board that is integrally molded using wood fibers or wood chips obtained from waste wood, And/or with the idea of obtaining a composite board with excellent fire protection performance by laminating and compositing wood particle boards and metal foil, a plurality of wood fiberboards/wood particle boards and metal foil were arranged alternately. Attempts were made to bond the sheets by heat pressing using an adhesive, but a puncture caused by moisture in the board material occurred during heat pressing, and the desired composite board could not be obtained.

This puncture phenomenon will be further explained below using a wood fiber board as an example. First, the wood fibers obtained by defibrating the chips are coated with adhesive, dried, and then
The wood fibers are piled up and made into a mat, which is then heated and molded to obtain a wood fiberboard. After the wood fiberboard is cured to an equilibrium moisture content by controlling the humidity and absorbing moisture from the atmosphere, the surface is sanded and cut to size. With this humidity control curing, the moisture content of the wood fiberboard obtained by heat pressing is very low and it is close to an absolutely dry state, so if sanding and cutting are performed in that state, the wood will become This is done to prevent the fiberboard from absorbing moisture and causing warping due to expansion. Wood fiberboards obtained in this way contain water up to the equilibrium moisture content, so when multiple wood fiberboards are laminated and heat pressed together with an adhesive, the water in the wood fiberboards evaporates. It was discovered that a force was generated that tried to escape from the tank, causing punctures due to the release of water vapor during depressurization. This phenomenon is the same when a wood chip board is used.

[0009] Therefore, the inventor of the present invention proposed that instead of the wood fiber board/wood chip board, a thermosetting resin adhesive was added to the wood fiber/wood chip board, and the dried material was dropped and deposited on a conveyor. The present invention was developed based on the idea of alternately laminating wood deposit layers and metal foil layers and then heat-pressing them to form an integral piece of adhesive.

[0010] That is, the present invention alternately arranges wooden deposited layers obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and drying them and depositing them on a conveyor and metal foil layers. , After laminating so that the woody deposited layer is placed on the front and back,
This is a method for manufacturing a composite board, which is characterized by integrally molding the composite board by heat-pressing and bonding.

As schematically shown in FIG. 1, the composite board manufactured according to the present invention has a wood fiber layer and/or a wood chip layer (hereinafter collectively referred to as these) on the front and back sides of the metal foil layer 2, respectively. (referred to as woody sedimentary layers) 1a and 1b form a sandwich structure in which layers 1a and 1b are laminated and bonded. In the configuration example shown in FIG. 1, the wood deposited layers 1a and 1b on the front side and the back side have approximately the same thickness, and the metal foil layer 2 is arranged approximately at the center in the thickness direction of the entire composite board. As shown in FIG. 2, the wood deposit layer 1a on the front side may be thinner than the wood deposit layer 1b on the back side, and the metal foil layer 2 may be arranged near the surface of the composite board. In addition, the woody deposited layers 1a, 1 on the front side and the back side
b may both be wood fiber layers or both wood chip layers, or the surface layer 1a may be a wood fiber layer and the back layer 1b a wood chip layer, or vice versa. It's okay. Any combination of these may be selected depending on the use of the composite plate. Furthermore, the number of wood deposited layers and metal foil layers is not limited, and as shown in FIG. It may also have a structure in which a woody deposited layer is placed on the back surface. Depending on the above-mentioned variable factors, it is possible to obtain composite plates with various configurations depending on their uses even if they have the same thickness.

[0012] In the production method of the present invention, wood fibers obtained by making chips from hardwoods such as lauan, capor, chestnut, and poplar, or from softwoods such as pine, cedar, and cypress, and then defibrating them according to a conventional method. , or small diameter wood, waste lumber,
Wood shavings obtained by cutting and crushing raw wood cores, waste wood chips, etc. are used as raw materials.

[0013] A urea resin adhesive, a phenol resin adhesive, a melamine resin adhesive, an epoxy resin adhesive, a polyisocyanate resin adhesive, or a composite resin adhesive thereof is applied to the obtained wood fibers or wood chips. Add a thermosetting resin adhesive such as The amount of these thermosetting resin adhesives added is preferably 10 to 20% by weight based on the wood fibers or wood chips, and the resin percentage is preferably 30 to 60%. The adhesive can be more uniformly mixed into the wood fibers if the resin content is low.

The metal foil layer is made of metal or alloy such as iron, aluminum, stainless steel, copper, etc., and has a thickness of 20 to 10
0μ metal foil is preferably used. The surface of this metal foil is subjected to antirust treatment such as plating treatment, if necessary. Further, metal foil with a plurality of micropores formed into a mesh shape, or a metal woven fabric woven using metal threads can also be used as the metal foil layer in the present invention. By using metal foil that has air permeability through micro holes, etc., moisture remaining in the wood fibers or wood shavings that have been added with adhesive and dried will be able to escape during heating and compaction. Since the movement of the pump is no longer restricted, it is possible to effectively prevent a puncture phenomenon that occurs when the pressure is released.

To explain in more detail the process of manufacturing a composite board according to the method of the present invention, taking as an example the case where a wood fiber layer is provided, the softwood or hardwood chips are steamed under high temperature and high pressure steam to be degreased and softened. After that, it is defibrated using a defibrating device to obtain wood fibers. Most of these wood fibers are 1 to 30 mm long and 2 to 300 μm in diameter, and are bundled with several to dozens of cell pores consisting of wood cells, duct pores, or tracheid pores. It has a rounded shape, and the cell walls around the fibers are often torn or cracked, so they absorb a lot of moisture and moisture.

After the obtained wood fibers are dried in a drying device, they are put into a mixing device, and the thermosetting resin adhesive is added and mixed therein. In the mixing device, arbitrary additives such as a sizing agent, a water generating agent, a smoke reducing agent, etc. can be mixed at the same time as necessary.

The wood fibers to which the thermosetting resin adhesive has been adhered are then dried while being conveyed through a hot air duct. The air blowing speed at this time can be adjusted over a wide range depending on the specific gravity of the wood fiber, the amount of feed, the processing capacity of the previous and subsequent steps, etc., but is generally about 15 to 20 m/sec. This hot air blowing dries the wood fibers to a moisture content of about 6 to 15%.

The dried wood fibers are put into a forming device and dropped onto a conveyor to form a wood fiber pile layer. FIG. 4 shows a schematic configuration of the overall apparatus used when manufacturing the composite board having the configuration shown in FIG.
Metal foil rolls 20a and 20b supplying metal foil between c.
After forming a laminate 12 in which wood fiber deposited layers and metal foils are alternately laminated, the cutter 14 cuts the laminate 16 into a fixed size laminate 16, which is then placed in a hot press 18. The desired composite plate as shown in FIG. 3 is obtained by charging and heating and pressing. When laminating the wood fiber deposit layer and the metal foil, by applying a thermosetting resin adhesive similar to the adhesive mixed with the wood fibers on the front and back surfaces of the metal foil, the composite board Adhesive strength can be further improved.

When the composite board manufactured by the present invention is used in a situation where a high degree of fire prevention performance is required, the wood fiber layer/wood chip layer 1a arranged at least on the surface side is obtained by It is preferable that the fibers or wood chips are subjected to fireproofing treatment in advance. This fire prevention treatment is, for example,
The voids within the cell pores and/or the inner wall surface of the cell pores and/or the wood fibers or wood chips before the thermosetting resin adhesive is added.
Alternatively, the outer periphery of the wood fibers or wood chips is treated with a nonflammable inorganic compound to be filled with, adhered to, or fixed to the outer periphery of the wood fibers or wood chips, and the details of this treatment are as follows, taking the case of wood fibers as an example. .

That is, before the thermosetting resin adhesive is added, the wood fibers have just been properly dried in a drying device and are placed in an aqueous solution of a water-soluble inorganic salt (hereinafter referred to as the "first liquid"). Soak and soak thoroughly. At this time, it is effective to forcibly accelerate the impregnation treatment by applying reduced pressure or increased pressure. Alternatively, the wood fibers may be brought into a high moisture content state without being dried, or once dried, immersed in water or warm water to absorb water to saturate the wood fibers, and then immersed in the first liquid for diffusion impregnation. Also good. As the first liquid, MgCl2,
MgBr2, MgSO4・H2O, Mg(NO3)2・
6H2O, AlCl3, AlBr3, Al2(SO4)
3, Al(NO3)3・9H2O, CaCl2, CaB
r2, Ca(NO3)2, ZnCl2, BaBr2, B
Examples include aqueous solutions such as aCl2.2H2O and Ba(NO3)2. By immersing the wood fibers in the first solution, ions of the inorganic salt of the solute diffuse into the cell pores of the wood fibers.

[0021] Next, a liquid removal process is performed to remove the excess first liquid. The liquid removal treatment is carried out by means such as centrifugal liquid removal, showering, and soaking in water, and by removing the excess first liquid, it is possible to avoid excessive production of nonflammable inorganic compounds on the surface of the wood fibers. suppresses and improves diffusion impregnation of the aqueous solution to be impregnated next. It also prevents nonflammable inorganic compounds from being produced in a free state that is not attached or fixed to wood fibers. After the liquid removal treatment, component crystals of the first liquid deposited on the surface are removed, if necessary.

Next, a compound liquid that reacts with the first liquid to produce a water-insoluble, nonflammable inorganic compound (hereinafter referred to as the "second liquid") is added to and mixed with the wood fibers using a blender, spray, etc. Alternatively, the wood fibers are impregnated with the second liquid by dipping. As in the case of the first liquid, impregnation of the second liquid into the wood fibers can be promoted by reducing or pressurizing the wood fibers. As the second liquid, Na2C
O3, H2SO4, (NH4)2CO3, Na2SO4
, (NH4)2SO4, H2PO4, Na2HPO4,
(NH4)2HPO4, H3BO3, NaBO2, NH
An example is 4BO2. 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, producing a nonflammable inorganic compound. . Nonflammable inorganic compounds produced 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, if barium chloride is used as the first liquid and ammonium hydrogen phosphate is used as the second liquid, the barium cations and phosphoric acid anions will react, producing barium phosphate and barium hydrogen phosphate. be done.

[0023] After the reaction is completed, the excess second liquid is removed by deliquification treatment by means such as centrifugal deliquidation or washing with water such as showering or soaking. The second liquid immersion process and the liquid removal process may be repeated multiple times as necessary. After the liquid removal treatment, dry to reduce the moisture content to 25% or less, preferably 7 to 7%.
It shall be 15%. Since this nonflammable inorganic compound is water-insoluble, after drying, it fills in, adheres to, or adheres to the inside of the cell pores of the wood fibers or the inner wall surface of the cell pores, and also adheres to or adheres to the outer periphery of the wood fibers. As a result, the nonflammable inorganic compound is present in a form that blocks or fills the pores and cracks appearing on the surface of the wood fibers.

[0024] The nonflammable inorganic compound is
It is preferable that it is mixed in at a ratio of 3% by weight or more, and if it is less than this, sufficient fire protection performance cannot be obtained. Further, in order to increase the reaction efficiency between the first liquid and the second liquid, it is preferable that the addition and mixing of the second liquid is carried out under a heated atmosphere, particularly at a temperature of 40°C or higher, more preferably 50°C or higher. Furthermore, if the first liquid and the second liquid are heated and the wood fibers are immersed therein, or when the wood fibers are immersed in the first liquid and the second liquid, electrical or mechanical vibrations are applied using ultrasonic waves, a vibrator, etc. Diffusion and reaction of the treatment liquid into the wood fibers are carried out well. Note that the order of processing with the first liquid and the second liquid does not matter, and it goes without saying that the processing with the second liquid may be performed first.

[0025] In this manner, a fireproof treated wood fiber is obtained in which the nonflammable inorganic compound is fixed to the cell pores or the inner wall surface of the wood fiber, and the nonflammable inorganic compound is also fixed or attached to the outer periphery of the wood fiber. The fireproof treated wood fibers are put into a mixing device as described above, and a thermosetting resin adhesive is added and mixed therein.

[0026] The fire prevention treatment for the wood fibers or wood chips may be performed by a method other than the above-mentioned method. For example, substances conventionally known as fire retardants, such as ammonium salts such as ammonium phosphate, ammonium sulfate, and ammonium bromide, alkali metal salts such as potassium carbonate, sodium carbonate, and potassium phosphate, and alkalis such as calcium chloride and magnesium chloride. It can also be carried out by impregnating wood fibers or wood chips in a solution of metal compounds such as earth metal salts, aluminum chloride, aluminum sulfate, etc., followed by drying.

[0027]

【Example】

[Example 1] Radiata pine chips at 160°C and 7 kg/cm2
It was boiled for 5 minutes to perform a defatting and softening treatment. The chips were defibrated using a defibrator refiner, and the resulting wood fibers were dried. This wood fiber was immersed in a 30% barium chloride aqueous solution for 10 minutes, subjected to a diffusion treatment, and then drained. This was dried with hot air to adjust its moisture content to 7%. This wood fiber is put into a blender device and ammonium phosphate is mixed with 40% of ammonium phosphate.
% aqueous solution is added and mixed to generate a nonflammable inorganic compound consisting of water-insoluble barium phosphate and barium hydrogen phosphate inside the cell pores of the wood fibers and on the outer periphery of the wood fibers, and then deliquified and washed with water. The moisture content was adjusted to 6% by hot air drying. The weight increase rate of wood fibers due to this fireproofing treatment is 40%.
Met.

[0028] Fireproof treated wood fibers are put into a blender, and in the blender 4% of the amount of wood fibers is added.
After adding and mixing a wax sizing agent of 10% and a phenolic resin adhesive of 10%, the mixture was conveyed to a forming device and dropped onto a screen conveyor to be deposited to form a wood fiber deposit layer.

On the screen conveyor, there are first to third forming devices that form three wood fiber deposit layers in this way, and a first forming device that supplies iron foil each having a thickness of 45 μm.
And the second iron foil supply roll, as shown in FIG. 4, from the downstream side in the conveyor conveyance direction, the first forming device, the first iron foil supply roll, the second forming device, the second iron foil supply roll, The third forming device was arranged in this order to obtain a continuous mat in which wood fiber deposited layer/iron foil/wood fiber deposited layer/iron foil/wood fiber deposited layer was deposited in this order from the surface side.

After cutting the continuous mat thus obtained to an appropriate length, it was inserted into a hot press and heated for 200 minutes.
Heat-press molded at ℃ for 5 minutes, thickness 13 mm, specific gravity 0.6
A composite board of No. 5 was obtained.

[0031] When this composite plate was subjected to a heating test, it was confirmed that it exhibited fireproof performance that passed the test as a noncombustible material.

[Example 2] Radiata pine raw wood or waste wood was put into a flaker to obtain flaky wood chips. After drying, the wood chips were sorted to collect appropriate flaky wood chips. After the wood chips were fireproofed in the same manner as in the case of the wood fibers in Example 1, they were put into a continuous mixer, and in the mixer, 1% wax sizing agent and 8% phenol were added to the amount of wood chips. After the resin adhesive was added and mixed, it was conveyed to a forming device and dropped onto a screen conveyor to be deposited.

On the screen conveyor, Example 1
In the same manner as above, a continuous mat was obtained in which the following steps were deposited in the order of wood chip deposit layer/iron foil/wood chip deposit layer/iron foil/wood chip deposit layer from the surface side.

After cutting the continuous mat thus obtained to an appropriate length, it was inserted into a hot press and heated for 200 minutes.
Heat-press molded at ℃ for 5 minutes, thickness 13 mm, specific gravity 0.5
A composite board was obtained.

[0035] When this composite board was subjected to a heating test, it was confirmed that it exhibited fireproof performance that passed the test as a noncombustible material.

[0036]

[Effects of the Invention] According to the method of the present invention, wood fibers or wood shavings coated with an adhesive and dried are used, and when deposited on a conveyor by a forming device, they are laminated alternately with metal foil. Therefore, it has excellent work efficiency and does not cause punctures even when depressurizing after hot pressing. Therefore, a composite board with excellent dimensional stability and improved fireproof performance can be efficiently produced.

[Brief explanation of the drawing]

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

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

FIG. 3 is a perspective view showing another structural example of a composite plate manufactured by the method of the present invention.

4 is an explanatory diagram showing a schematic configuration of an apparatus used when manufacturing the composite plate of FIG. 3. FIG.

[Explanation of symbols]

1a Woody sediment layer 1b Woody sediment layer 1c Woody sediment layer 2 Metal foil layer 2a Metal foil layer 2b Metal foil layer

Claims (4)

[Claims] Claim 1: Wooden deposited layers obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and drying them are deposited on a conveyor, and metal foil layers are alternately arranged. A method for manufacturing a composite board, which comprises laminating the wood deposited layers on the front and back sides, and then heat-pressing and bonding and integrally forming the composite board. 2. After applying a thermosetting resin adhesive to the front and back surfaces of the metal foil layer, laminating it with the wood mat;
A method for manufacturing a composite board according to claim 1. 3. The method for manufacturing a composite plate according to claim 1, wherein a metal foil having a plurality of micropores is used as the metal foil layer. 4. The method for manufacturing a composite board according to claim 1, wherein the wood fibers or wood chips are subjected to fire prevention treatment in advance.