JP2005231152A - Woody board manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a woody board manufacturing method capable of efficiently manufacturing a woody board of high quality using wood chips as a raw material in a short time and capable of achieving cost reduction. <P>SOLUTION: In the method for manufacturing the woody board using wood chips as the raw material, a water soluble phenol resin is used as an adhesive and the raw material impregnated with the water soluble phenol resin is charged in a predetermined molding container to be molded under heating and pressure by electromagnetic wave heating. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a wooden board using wood chips as a raw material, and more particularly to a method capable of producing a high-quality wooden board in a short time by utilizing the characteristics of a water-soluble phenol resin and electromagnetic waves. It is.

  Today, a large amount of building waste such as small pieces of wood is discharged as a building by-product. Disposing of this building waste by incineration has been a problem in terms of environmental protection and the like, and it is currently attempted to reuse it in some form.

  As one of the reuse methods, it is generally known that the building waste material is crushed into chips by a crusher and made into a board so that it can be reused as a building board or a road laying material as a wooden board. ing. As a manufacturing method of such a wooden board, a building waste material crushed into chips is impregnated with a thermosetting phenolic resin or amino resin adhesive, and heat and pressure are simultaneously applied thereto. Manufactured. The hot pressing method employs a hot press method, that is, an external heating method in which heat is applied from the outside of the object to be heated and heat is gradually transferred from the outside to the inside by heat conduction.

  However, this hot-press molding by the external heating method gradually transfers heat from the outside of the object to be heated to the inside by heat conduction, so it is long enough to heat the one with a large cross-sectional size or one with a large capacity to the inside. It takes time. This is even more so with wood with low thermal conductivity. As a result, a temperature difference is generated between the surface and the inside of the heated body, and only the surface temperature rises too much while the internal temperature is low, and the surface of the heated body often burns. In addition, the quality of the molded wood board is not constant and varies, and many of the products that cannot be actually used as wood boards are molded as defective products, resulting in a significant cost increase. .

  In addition, wood boards in the past were manufactured by simply painting and solidifying wood chips and adhesives as raw materials and hot-press molding, but only with this process, the adhesive reaches all corners of the whole wood chips. In many cases, the strength of the wood board is not sufficient, so there is a problem that it cannot be used as a product unless a plate-like surface layer material is applied as a reinforcing material, such as being used only as a structural material or a base material. .

Furthermore, in the production of conventional wooden boards, in order to use wood chips as a raw material for the wooden boards, it is necessary to dry the moisture content of the wood chips to 4 wt% or less, and therefore, it is used for the drying. A huge amount of kerosene was needed.
JP 2002-273711 A Registered Utility Model No. 3080504

  In view of the above problems, the present invention uses a water-soluble phenol resin as an adhesive, and adopts an internal heating method using electromagnetic waves as a heating method in hot press molding, thereby improving water resistance, weather resistance, durability, An object of the present invention is to provide a method for producing a wooden board that can produce a high-quality wooden board having excellent water permeability and a low environmental load, and that can improve work efficiency and reduce costs.

  In order to achieve the above object, the present invention is a method for producing a wooden board made of wood chips, using a water-soluble phenol resin as an adhesive, and impregnating the water-soluble phenol resin. The raw material is filled into a predetermined molding container and hot-pressure molded by electromagnetic wave heating.

  In addition, the present invention may employ a method in which the moisture content of the wood chips as the raw material is dried to 12 wt% or less and used as a raw material for the wooden board.

  Furthermore, this invention can take the structure which uses what mix | blended hardening accelerators, such as iron powder, with water-soluble phenol resin as said adhesive agent.

  Furthermore, the present invention can employ a method of hot pressing by using a high frequency among the electromagnetic waves.

  Furthermore, the present invention can also employ a method of hot pressing by using a microwave among the electromagnetic waves.

  According to the method for producing a wooden board of the present invention, since a water-soluble phenol resin is used as an adhesive, water resistance, weather resistance, durability, and further excellent water permeability and high environmental impact and low environmental impact. Wood board can be manufactured.

  Moreover, since the moisture content of the wood chip used for the production of the wood board according to the present invention is 12 wt% or less, the amount of kerosene used for drying the wood chip can be reduced, and the time required for drying can be reduced. It leads to shortening and cost reduction.

  Furthermore, in the hot press molding according to the present invention, an electromagnetic wave press method, that is, an internal heating method in which heat is directly applied to the inside of the object to be heated is adopted. Mass production is possible efficiently and productivity is remarkably increased. Furthermore, there is no occurrence of scorching of wood chips, and it is possible to manufacture a wooden board with a certain level of quality, and the occurrence of defective products. This also has the effect of reducing costs and reducing costs.

  Furthermore, the wood chips used as a raw material are impregnated with a water-soluble phenol resin, so that the entire surface of each wood chip is covered with the water-soluble phenol resin, so that the wood chips are firmly attached to each other. Adhesive strength can be secured sufficiently without sticking a plate-like surface layer material as a reinforcing material.

  Furthermore, the entire surface of the wood chip is covered with a water-soluble phenol resin, and the moisture does not easily enter the inside of the wood chip. Therefore, due to the influence of atmospheric humidity, which is a characteristic of the wooden board. The problem of expansion and contraction does not occur, and a wood board with excellent dimensional stability against moisture can be obtained.

  In addition, since the wood chips are firmly bonded to each other as described above, it is possible to form an air layer inside the wooden board by changing the pressure at the time of hot-pressure molding, and the heat insulation effect is high. It is possible to obtain wood boards with high added value and utility value, such as wall coverings and floor materials with excellent water permeability.

  For the purpose of producing high-quality wood boards made from wood chips in a short time and at a low cost, water-soluble phenolic resin is used as an adhesive, and an internal heating method using electromagnetic heating is adopted as a hot-press molding method. It was realized by doing.

  The raw material used in the method for producing a wooden board according to the present invention is obtained by processing wood chips as building by-products such as wood chips and wood fibers discharged as building waste into chips. A crusher is used to manufacture such wood chips. The size of the wood chips crushed by the crusher is about 0.1 to 10 mm in thickness, about 10 to 100 mm in length, and about 1 to about 1 in width. It shall be about 15 mm. The wood chips thus processed are classified into four types according to size, and are put into a dedicated steel basket according to type.

  The dedicated basket containing the wood chips is carried into the drying chamber as it is, and the wood chips are dried until the moisture content falls within the range of 8 wt% to 12 wt%. Conventionally, the moisture content of wood chips that can be used as a raw material was 4 wt%, but the moisture content of wood chips in the present invention is sufficient if it is 12 wt% or less. The moisture content of the wood chips before drying is about 20 wt%, and the temperature in the drying chamber is set to 50 ° C. to 80 ° C., and drying is performed for about 48 hours under such conditions, the wood chips require the moisture content. A dry state of 8 wt% to 12 wt% is reached. When drying wood chips, a once-through boiler is usually used, and kerosene is used as the fuel for the boiler.

  Here, the formula for calculating the amount of water evaporation when the moisture contained in the wood chip is dried is shown in the following formula 1 in the conventional case and in the following formula 2 in the present invention. Equation 1 is calculated with the moisture content of the dried wood chips being 4 wt%, and Equation 2 is calculated with the moisture content of the dried wood chips being 12 wt%. In addition, we take cedar wood as an example of building waste as a raw material, and the moisture per cubic meter of cedar wood as a construction material before becoming waste wood is about 340 kg, and it is used for wooden boards Since the raw material is building waste such as small pieces of wood, it is assumed that approximately 90 kg of water has evaporated per cubic meter when the building waste is chipped. The calculated amount of water is 250 kg.

  As shown in the above formula, it is necessary to evaporate about 236 kg of water in the prior art, whereas in the present invention, it is sufficient to evaporate about 209 kg of water, and the amount of water evaporation of about 27 kg can be suppressed. When this is converted into the amount of kerosene in the once-through boiler used for drying, it is expressed by the following formula 3 in the conventional case and by the following formula 4 in the present invention. In order to evaporate 1 kg of water, about 0.15 liters of kerosene is required with a once-through boiler, and the heat loss in actual drying is estimated to be about 20%.

  According to the above formula, the amount of kerosene of 42.48 liters was conventionally required to dry the wood chips, whereas the amount of kerosene of 37.62 liters was sufficient according to the present invention, The calculation can save about 4.9 liters of kerosene. Since the capacity of wood chips used for the wood board that can be manufactured with one thermo-press molding machine according to the present invention per year is about 4620 cubic meters, the same capacity wood chips are molded in a conventional thermo-pressure molding machine. Compared with the case of doing so, the amount of kerosene of about 22,638 liters can be saved in one year. This not only leads to cost reductions, but burning kerosene naturally results in carbon dioxide emissions. Even very beneficial.

  Next, the dried wood chip is put in a water tank containing an adhesive in a state where it is put in a dedicated basket, and is stirred and mixed to perform a step of impregnating the wood chip with the adhesive. At this time, the mixing ratio of the wood chip and the adhesive is agitated and mixed at a ratio of 20% by weight of the adhesive to 3000 g of the wood chip. The time required for impregnation is about 30 minutes.

  In general, adhesives used for wood bonding are roughly classified into natural systems such as starch and synthetic resin systems, and the adhesives used in hot-press molding are synthetic resin systems. Synthetic resin adhesives include thermoplastic synthetic resins such as vinyl acetate and vinyl chloride and thermosetting synthetic resins such as phenol and amino. And, in order to produce a wooden board by hot-pressing wood chips, phenolic and amino synthetic resins having thermosetting properties are used as adhesives. Table 1 shows.

  As shown in the above table, phenolic resins and amino resins have conflicting properties, and as to which one is used as an adhesive, if quality is given priority, productivity is inferior, and if productivity is given priority, quality is inferior. Will end up. The present invention employs an internal heating method using electromagnetic wave heating as a method of hot press molding, so that it has succeeded in shortening the time required for molding and has improved productivity, and thus obtains a wood board that is excellent in terms of quality. Therefore, phenolic resin is used as an adhesive.

  In the present invention, among phenolic resins, a water-soluble phenolic resin is used as an adhesive. In the conventional molding of wood boards, methanol has been used to dilute the resin liquid as an adhesive, but this methanol is a very toxic substance that can lead to blindness or death if handled incorrectly. The handling was very careful. On the other hand, since the water-soluble phenol resin can be easily diluted with water, it is very convenient and easy to handle, and is very beneficial from the viewpoint of safety.

  It is also effective to use a water-soluble phenol resin further blended with a hardening accelerator such as iron powder as an adhesive. In such a case, rather than using only the water-soluble phenol resin as the adhesive, the internal heating of the heated object by electromagnetic waves is performed more efficiently, which contributes to shortening the time required for molding. In addition, this hardening accelerator is mix | blended in the ratio of 5% of weight ratio with respect to water-soluble phenol resin.

  The wood chip impregnated with the water-soluble phenolic resin is taken out of the water tank, placed on a dedicated table, drained of the water-soluble phenolic resin solution, and then transported again into the drying chamber and touched with a hand. Dry until free. By passing through this step, the water used as the diluent is evaporated, and the workability at the time of hot pressing is increased.

  The wood chip obtained through the above steps is filled in a predetermined container, and then the side wall of the container is removed while maintaining the shape of the filled wood chip without breaking the shape. Then, it is loaded into an electromagnetic wave press machine, compressed at a pressure of 10 to 20 kg per square centimeter, and subjected to electromagnetic wave heating for several minutes in that state. About heating time, it changes with the thickness of the wood chip with which the predetermined container was filled. This heating by electromagnetic waves produces the anchoring effect by the adhesive and the promoting effect of the attractive force between the molecules in the adhesive and the wood chip molecules, and a wood board with excellent quality is produced in a very short time. Become.

  Regarding the electromagnetic waves used in the internal heating method employed in the present invention, high frequency or microwaves of the electromagnetic waves are used when actually heating the electromagnetic waves. High frequency refers to a region where the frequency of electromagnetic waves is 1 MHz to 300 MHz, and microwave refers to a region where the frequency of electromagnetic waves is 300 MHz to 300 GHz. The heating principle is the same for this high frequency and microwave, but the applications and features are different. That is, the high frequency wave is suitable for heating one having a large cross-sectional size or a long shape, and the microwave is suitable for heating one having a relatively small cross-sectional size or an irregular shape. Therefore, it is desirable to make appropriate use of high frequency and microwave for each application by utilizing this feature.

  Here, the performance comparison between the hot press molding by the conventional hot press method and the hot press molding by the electromagnetic wave press method according to the present invention is shown in Table 2 below. In addition, it is a performance comparison in the case of manufacturing a wood board of 950 mm in length, 1850 mm in width, and 60 mm in thickness as a comparison object.

  As shown in the above table, the heat press molding by the electromagnetic wave press method is shorter than the hot press method, and the molding time is shortened. ing. Moreover, since the molding time is shortened, it is clear that productivity is remarkably improved and the amount of wood chips used is increasing.

  Further, a performance comparison such as strength between the wood board manufactured by the manufacturing method according to the present invention, a concrete flat block, and an interlocking block is shown in Table 3 below. At that time, the standard size of the flat plate block made of concrete is 300 mm long, 300 mm wide, and 60 mm thick, so prepare three pieces of wood board molded in the same size, test each, and average The value was calculated and the performance was compared. As a test method, the bending strength is measured according to 9. Bending test in JIS standard Z2101 7.2 compressive strength, hydraulic permeability counting in interlocking block pavement design guidelines published by the Interlocking Block Pavement Technical Association 9.2.4 The weather resistance was subjected to an exposure test for 250 hours according to WS-A of JIS standard A1415.

  According to the above table, the wood board produced by the production method according to the present invention has a bending strength equivalent to that of an ordinary concrete flat plate block. It has a strength five times higher. Further, the water permeability count is more than twice that of the water-permeable concrete flat block. In terms of weather resistance, no discoloration or cracking occurred in any of the three wooden boards tested. Therefore, it is clear that the wood board manufactured by the manufacturing method according to the present invention is superior in the strength and water permeability to the concrete product, and further, the weight is lighter than that of the concrete product, so that the workability is excellent.

  Here, in order to compare the performance with the interlocking block, the quality standard of the interlocking block is shown in Table 4 below.

  Comparing the test results of the wooden board shown in Table 3 above with the quality standards shown in Table 4, the wooden board manufactured by the manufacturing method according to the present invention has a bending strength almost equal to that of a normal interlocking block. And 1.5 times stronger than the water-permeable interlocking block. Further, the water permeability count is slightly more than twice that of the water permeable interlocking block, and it is clear that the wood board manufactured by the manufacturing method according to the present invention is excellent in the interlocking block as a whole.

  The wood board manufactured by the manufacturing method according to the present invention was also tested for oil resistance, acid resistance, and alkali resistance. As a test method at that time, it was performed according to JIS standard A1454 6.10. Contaminated materials were tested on three wooden boards using a lubricating oil for acid resistance, 5% hydrochloric acid for acid resistance, and 2% soda aqueous solution for alkali resistance. As a result, as for the oil resistance, all three sheets were infiltrated with oil, but the others were not abnormal. For acid resistance, all three sheets were abnormal, and for alkali resistance, all three sheets were infiltrated with aqueous solution, but the others were not abnormal. From this result, the wood board manufactured by the manufacturing method according to the present invention can be used in a wide range regardless of indoor or outdoor.

  According to a general hot-press molding machine, the wood board can be manufactured with a thickness of 6 to 100 mm, and a maximum of vertical x horizontal is 1200 mm x 2400 mm. However, it is not limited to this size, and varies depending on the size range in which the molding machine can be manufactured. In addition, because wood chips are used as raw materials, the thickness and length x width dimensions of the wood board produced can be changed by changing the amount of wood chips used, the size of the container filled with the wood chips, the position of the side wall of the container, etc. Can be easily resized.

  The wood board manufactured through the above steps is taken out from the molding machine. In the periphery of the taken-out wooden board 4, roughening has occurred, such as wood chips being pushed out by compression by a molding machine. Therefore, finish cutting is performed on the periphery of the four to complete the final product.

  The wood board that has been hot-pressure molded by the manufacturing method according to the present invention is formed by bonding individual wood chips to each other, and the entire board is not solidified with an adhesive. By changing the compressive strength, it is possible to produce a wood board in which air gaps are formed on the bonding surfaces of the wood chips and an air layer is formed inside. A wooden board having such an air layer is excellent in heat insulation effect and water permeability, and can be used as a board with high added value in various fields such as wall coverings and flooring.

  In addition, the finished top and bottom surfaces of the manufactured wood board can be displayed in a wide variety of ways, such as differences in the size of the wood chips used as raw materials, differences in the crushing method using the crusher, and the combination of wood chips of different shapes. A layer surface is formed. Therefore, it can be used in various fields as a high added value board depending on the pattern appearing on the surface.

It is a schematic explanatory drawing which shows the process in which a wooden board is manufactured with the manufacturing method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Dedicated basket 2 Drying room 3 Water tank 4 Phenol resin aqueous solution 5 Draining board 6 Wood chip 7 Side wall 8 Wood board

Claims (5)

  A method for producing a wood board using wood chips as a raw material, wherein a water-soluble phenol resin is used as an adhesive, and a raw material impregnated with the water-soluble phenol resin is filled in a predetermined molding container. A method for producing a wooden board, characterized by hot-press molding by electromagnetic heating.   The method for producing a wooden board according to claim 1, wherein the moisture content of the wood chip as the raw material is dried to 12 wt% or less.   The method for producing a wooden board according to claim 1 or 2, wherein the adhesive is a water-soluble phenol resin blended with a curing accelerator.   The said electromagnetic wave is a high frequency, The manufacturing method of the wooden board of Claims 1-3 characterized by the above-mentioned. The said electromagnetic wave is a microwave, The manufacturing method of the wooden board of Claims 1-3 characterized by the above-mentioned.

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