JPH04216041A - Manufacture of composite panel - Google Patents

Abstract

PURPOSE:To obtain a composite panel excellent in fire resistant properties by a method wherein wooden mat layers each obtained by temporarily pressing wooden fibers or cut wood pieces to which a thermosetting resin adhesive is added and a metal foil layer are alternately laminated so that the wooden mat layers are arranged on the front and rear sides of the metal foil layer and subsequently pressed and bonded under heating to be integrally molded. CONSTITUTION:A composite panel has a sandwich structure wherein wooden mat layers 1a, 1b are respectively laminated and bonded to the surface and rear of a metal foil layer 2. The wooden mat layers 1a, 1b are almost equal in thickness and the metal foil layer 2 arranged at the almost central part in the thickness direction of the whole of the composite panel or the wooden mat layers are different in thickness and the metal foil layer may be arranged in the vicinity of the surface of the composite panel. Chips of a needle-leaf or broadleaf tree material are beaten to obtain wooden fibers and a thermosetting resin adhesive is added to the wooden fibers. The metal foil layer to be used is composed of a metal such as Fe or Al or an alloy thereof and has thickness of 20-100mum. All of those layers are 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 is close to an absolutely dry state, so if sanding and cutting are performed in that state, the wood fiberboard 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 present inventor used a wood mat layer obtained by adding a thermosetting resin adhesive to wood fibers/wood chips and temporarily pressing them, instead of the wood fiber board/wood chip board. The inventors came up with the idea of alternately laminating the wood mat layers and the metal foil layers and then heat-pressing them to form an integral piece of adhesive, which led to the present invention.

That is, in the present invention, wood mat layers obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and temporarily pressing the wood mat layers and metal foil layers are arranged alternately on the front and back surfaces. This is a method for manufacturing a composite board, which is characterized in that the wood mat layer is laminated so that the wood mat layer is arranged, and then heat-pressed and bonded and integrally formed.

As schematically shown in FIG. 1, the composite board manufactured according to the present invention has a sandwich structure in which wood mat layers 1a and 1b are laminated and bonded to the front and back sides of a metal foil layer 2, respectively. In the configuration example of FIG. 1, the wood mat layers 1a and 1b on the front side and the back side have approximately the same thickness,
The metal foil layer 2 is arranged approximately at the center in the thickness direction of the entire composite board, and as shown in FIG. The foil layer 2 may be arranged near the surface of the composite board. In addition, the wooden mats 1a and 1 on the front side and the back side
b may both be wood fiber mats, or both may be wood chip mats, or the surface layer 1a may be a wood fiber mat and the back layer 1b a wood chip mat, or vice versa. It's okay. Any combination of these may be selected depending on the use of the composite board. In addition, the number of wood mat layers and metal foil layers is not limited, and the structure is such that multiple metal foil layers and multiple wood mat layers are alternately laminated, and the wood mat layers are arranged on the front and back surfaces. It's okay. 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.

[0015] To explain in more detail the process of manufacturing a composite board according to the method of the present invention using a wood fiber mat as an example, 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%.

[0018] The dried wood fibers are put into a forming device, dropped onto a conveyor, piled up and laminated, and then temporarily compressed to obtain a wood fiber mat that can be handled. After cutting this wood fiber mat into appropriate dimensions, the wood fiber mats are stacked alternately with metal foil so that the wood fiber mats are placed on the front and back sides, and the desired composite board is obtained by further heating and pressing. When laminating the wood fiber mat and metal foil, a thermosetting resin adhesive similar to the adhesive mixed with the wood fibers is applied to the front and back surfaces of the metal foil in advance to bond the composite boards together. Strength can be further improved.

When the composite board produced according to the present invention is used in a situation where a high degree of fire protection performance is required, the wood fibers or wood chips are used to obtain the wood mat layer 1a disposed on at least the surface side. It is preferable to apply fireproofing treatment to the material in advance. This fire prevention treatment is performed, for example, on the voids in the cell pores and/or the inner wall surface of the cell pores of the wood fibers or wood chips before the thermosetting resin adhesive is added. The outer periphery of the fiber is treated with a nonflammable inorganic compound to be filled with, adhered to, or fixed to the outer periphery of the fiber.This treatment will be described in detail below, taking the case of wood fiber 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 10% wax sizing agent and 10% phenolic resin adhesive, the mixture was conveyed to a forming device and dropped onto a screen conveyor to be deposited.

[0029] The accumulated wood fibers were cut into appropriate lengths and then inserted into a hot press and preheated and pressed to obtain a fireproofed wood fiber mat.

[0030] Using the three wood fiber mats obtained in this way and two sheets of 45 μm thick iron foil, from the surface side the wood fiber mat/iron foil/wood fiber mat/iron foil/wood fiber mat were separated. After laminating them in order, insert them into a hot press for 20 minutes.
Hot pressure molded at 0℃ for 5 minutes, thickness 13mm, 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.

[0033] The accumulated wood chips were cut into appropriate lengths, and then inserted into a hot press and temporarily pressed to obtain a fireproofed wood chip mat.

[0034] Using the three wood chip mats obtained in this way and two sheets of 45 μm thick iron foil, from the surface side: wood chip mat/iron foil/wood chip mat/iron foil/wood shavings. After laminating the single mats in order, insert them into a hot press and heat them at 200℃ for 5 minutes.
A composite plate having a thickness of 13 mm and a specific gravity of 0.5 was obtained by hot-pressing for 1 minute.

[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.

[Example 3] Fireproof treated wood fiber mat obtained in Example 1 and Example 2
Using the fire-retardant treated wood chip mat obtained in step 1 and 45 μm iron foil, the layers were laminated in the order of wood fiber mat/iron foil/wood chip mat/iron foil/wood fiber mat from the front side, and then inserted into a hot press. Then, hot-press molding at 200℃ for 5 minutes to a thickness of 1
A composite plate having a thickness of 3 mm and a specific gravity of 0.60 was obtained.

[0037] 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.

[0038]

[Effects of the Invention] According to the method of the present invention, wood fibers or wood shavings coated with an adhesive and dried are temporarily pressed to produce a wood mat that can be handled. Since it is hot-press-formed after being laminated with metal foil, it has excellent work efficiency and does not cause punctures even when decompressing 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.

[Explanation of symbols]

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

Claims (4)

[Claims] [Claim 1] A wood mat layer obtained by adding a thermosetting resin adhesive to wood fibers or wood chips and temporarily pressing the mixture;
A method for manufacturing a composite board, comprising laminating metal foil layers alternately so that the wood mat layers are placed on the front and back sides, and then heat-pressing and bonding and integrally molding. 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.