JP2008238574A - Method of welding fiber plates and fiber plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To weld fiber plates in which different resins are mixed without generation of thermal strain. <P>SOLUTION: A method of welding fiber plates comprises preparing fiber plates from waste textile products, applying a heat-generating material to welding parts of the fiber plates, laminating the fiber plates or attaching rib strips temporarily, promoting inside heating of the heat-generating material by laying in a high-frequency electric field so as to soften or melt the fiber plates indirectly and pressure-molding. The heat-generating material is e.g. an aqueous solution of glycerol having a high dielectric loss factor and is made to permeate into granular or fibrous wood waste under vacuum decompression so as to permeate into the central part of the pieces of the waste. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fiberboard welding method and a fiberboard. Fibreboard is a board manufactured by reusing fibers recovered from waste fiber products. As a substitute for wooden boards (single or plywood), materials for civil engineering, architecture, furniture, logistics, packaging, etc. Can be used as automobile parts.

Wooden boards are highly field workable and can be further constructed by using nails or adhesives. On the other hand, while civil engineering and building materials that ensure water resistance, corrosion resistance, heat insulation, sound insulation, physical strength, etc. are required, materials with high impact energy and earthquake resistance are required. . Textile products such as curtains, carpets, and clothing are blended with wool, cotton, nylon, polyester, etc. in order to achieve a product configuration that takes into consideration the feel and design. In this way, waste fiber products in which various materials are blended are left to incineration as waste because they are difficult to separate and separate.
JP-A-8-138819 Japanese Patent Laid-Open No. 8-531942 International Publication Pamphlet PCT / JP97 / 02289

  Various techniques for welding plastic using high frequency are known. However, in any case, it is assumed that the plastic material is specified in advance. In the case of fiberboard made of waste fibers mixed with various types of materials such as nylon, polyester, wool, etc., self-welding or normal compatibilizers do not function, so although high frequency dielectric heating and microwave heating are attempted, cooling At the same time, it peels or separates.

The present invention is to provide a new structure with improved physical strength by obtaining a fiberboard using a blended material or the like and then performing welding or lamination at an arbitrary position. For this purpose, the present invention proposes to use a cellulose (C ₆ H ₁₀ O ₅ ) contained in wood waste as a common compatibilizing agent for fiberboard and to weld dissimilar plastics in an incompatible relationship. To do. However, when a cellulose component contained in wood waste was applied with a compatibilizing agent or a kind of adhesive to the fiberboard, and welding was attempted, although the fiberboard's welding function was confirmed, thermal distortion occurred in the fiberboard. A stable molded body could not be constructed.

  Accordingly, an object of the present invention is to weld a fiberboard in which different types of plastics are mixed without causing thermal strain.

Waste fiber products contain different fiber materials such as nylon, polyester and wool. After the waste fiber products mixed with such various materials are finely bent into single fiber hairs, cellulose fiber hairs (C ₆ H ₁₀ O ₅ ) opened from wood scraps are mixed and stirred and mixed. After applying the above, by pressing and solidifying with heat and pressure, a fiberboard in which waste fibers and the like are mixed can be obtained.

  High-frequency heating capable of local heat generation is the most efficient way to weld or laminate polymer materials that are incompatible with nylon, polyester, polypropylene, etc. while suppressing thermal strain. . In the high-frequency heating, only the heating element is heated and heated by applying high-frequency energy only to the heating element applied to the surface of the fiberboard, and the local heating action of the fiberboard can be promoted. When a high frequency strikes the dielectric, the dipole that forms the dielectric vibrates violently due to the change in the polarity of the electric field. When this dipole vibration can no longer follow the external electric field, it changes into thermal energy due to molecular friction, and the intensity of the radio wave rapidly attenuates. Since the amount of heat generation is proportional to the dielectric loss coefficient (εγtanδ) of the dielectric, a substance having a large dielectric loss coefficient, such as a solution of glycerin aqueous solution, is employed as the heating element.

  The heating element absorbs high-frequency energy and promotes heating and heating from the inside of the heating element. By making the heating element impregnated with particulate or fibrous wood chips, a high heating and heating effect is achieved. I can expect. In other words, the heating element impregnated with wood waste becomes heated and heated by placing it in a high-frequency electric field, but since it is impregnated with wood waste and in a sealed state, it maintains a saturated state and has a higher temperature raising effect than usual. Will be encouraged. The heat is rapidly absorbed by the heating element impregnated with wood waste, and in the case of a glycerin aqueous solution, the vibrational energy between the glycerin constituent molecules becomes frictional heat, and the temperature rises from within the heating element. The glycerin aqueous solution is contained in the wood waste and is in a sealed state, so that evaporation is inhibited and saturated inside the wood waste, which is faster than usual, that is, compared to the case where it is not sealed, and a high temperature rising effect is obtained. .

  Thus, in order to laminate and weld the fiber boards while suppressing the occurrence of thermal strain, after applying the heating elements to the surface layer of the fiber boards, the heating elements are placed in a high-frequency electric field. Since the surface layer of the fiberboard, which is centered on the heating element and promoted local heat generation, is softened and melted, it can be welded via the cellulose component by laminating the fiberboard and performing pressure molding. In addition to laminating a plurality of fiber boards and welding them together, it is possible to obtain a structure of any shape, such as welding ribs to the surface of the fiber boards.

  According to the present invention, it is possible to perform welding with suppressed thermal strain on a fiberboard made of waste fibers containing different types of plastic such as blended fibers. In addition, since such welding is possible, it is possible to build an arbitrary structure by laminating and welding the fiberboards and welding rib plates, etc., and physical strength and functionality The fiber board which aimed at improvement of can be provided.

  Embodiments of the present invention will be described below. First, the heating element will be described, and then the fiberboard welding will be described.

  As described above, when a high frequency wave hits a dielectric, particularly a substance having a large dielectric loss coefficient, it is converted into thermal energy by molecular friction, and the intensity of the radio wave is rapidly attenuated (absorbed). Such substances having a high frequency attenuation effect include water, nickel hydroxide, ethylene glycol, propylene glycol, sodium hydroxide, pentaerythritol, glycerin, and many other substances. Here, although not particularly limited, a glycerin aqueous solution will be described as an example.

  Even if the glycerin aqueous solution itself is applied to the fiberboard surface and irradiated with high frequency, dissimilar materials such as nylon, polyester, and polypropylene cannot be welded. As a result, the temperature rises and the heating state necessary for welding the fiberboard cannot be led. Therefore, as shown in FIG. 2 and FIG. 4, a heating element in which a glycerin aqueous solution is impregnated in a central part of a pulverized particulate or fibrous wood waste to enclose the glycerin aqueous solution with a cellulose component derived from wood waste and is in a sealed state. To achieve a higher heat generation effect. In this case, particulate or fibrous wood waste becomes a carrier of the glycerin aqueous solution, and a heating element having both an action as a compatibilizing agent for different plastics and a high-frequency attenuation effect is obtained.

As shown in FIG. 3, the aqueous glycerin solution is prepared by mixing 0 to 40% of water (H ₂ O) with respect to glycerin (C ₃ H ₈ O ₃ ) 100 and stirring uniformly in a heated state of about 20 to 60 ° C. • Obtained by mixing. The lower limit “0” does not mean literally, but it means that a small amount is possible. Glycerin (C ₃ H ₈ O ₃ ) has a very low dielectric constant and specific heat relative to water (H ₂ O), and has a high permeability to wood chips, so it can be expected to have a high high-frequency damping effect. Can be understood as

  Table 2 shows a comparison between the boiling point of water and glycerin alone and the temperature when impregnated into the granular wood chips and irradiated with high frequency. As shown in Tables 1 and 2, glycerin having a boiling point of 171 ° C. was impregnated with a glycerin aqueous solution deeply in the central part of the particulate wood waste, encapsulated with a wood component derived from wood waste, sealed, and then subjected to high frequency (2 .45 GHz) raises the temperature and generates heat up to about 1.4 times the boiling point of a single substance.

As described above, in order to obtain a higher temperature rising effect, the glycerin aqueous solution is infiltrated deep into the central part of the wood chip. The wood chips as the carrier of the glycerin aqueous solution do not need to be particularly limited in material and the like, and waste materials such as thinned wood can be used effectively. Waste materials such as thinned wood are finely pulverized and adjusted to an almost uniform size of about 50 μm to 3 mm to form particles or fibers. Wood waste is mainly composed of cellulose (C ₆ H ₁₀ O ₅ ) and can be considered as a mixture of lignin and hemicellulose. Etc. are not limited in detail.

  Usually, about 6 to 15% of water already exists in the wood chips finely pulverized into particles or fibers. Accordingly, in order to further impregnate the glycerin aqueous solution, it is desirable to dehydrate and dry the wood chips to reduce the moisture content and to change the wood chips to highly absorbent wood chips. Therefore, the remaining water is evaporated by putting the wood chips into the vacuum vessel and placing them in a heated / depressurized state. Specifically, by reducing the pressure from 1 atm to -0.6 atm in a heated state at 60 to 100 ° C in a sealed container, the water remaining in the wood chips is evaporated, and the water content is reduced. Reduce to 3% or less.

  Wood chips in an absolutely dry state with a water content adjusted to 3% or less are put into an aqueous glycerin solution and impregnated. Since the glycerin aqueous solution has a high viscosity and cannot be impregnated deeply into the central part of the wood chip only by being immersed in the solution, the process proceeds to the next pressurizing and boiling step. That is, the wood waste thrown into the glycerin aqueous solution keeps the container sealed, raises the pressure to about 1.6 atm, and performs heating and boiling treatment at about 60 to 200 ° C. to deepen the central portion of the wood waste. Can be infiltrated with an aqueous glycerin solution. In this way, after once vacuuming and dehydrating treatment is performed to make it completely dry, a boiling treatment accompanying heating and pressure increase is performed again so that the aqueous glycerin solution is impregnated deep into the central part of the wood chips.

  The glycerin aqueous solution impregnated into the wood chips by the pressure / boiling treatment ensures a high content of 20% or more. In order to obtain a high temperature rising effect of about 150 to 200 ° C. by high-frequency heating, it is necessary to impregnate a glycerin aqueous solution deep into the central part of the wood chip and seal it. When high-frequency heating is performed in a state where the glycerin aqueous solution is sealed with wood chips, the glycerin aqueous solution becomes saturated as the temperature rises, and a higher temperature rise occurs. In order to construct a state where the glycerin aqueous solution is sealed in the wood waste, hot air of 20 to 80 ° C. is applied to volatilize the glycerin aqueous solution attached to the surface layer, and only the surface layer of the wood waste is dried. In the wood waste whose surface layer has been dried by hot air, an aqueous glycerin solution remains in the central portion. Specifically, the wood chips that have undergone the surface layer drying treatment carry 5 to 20% glycerin aqueous solution.

Next, the fiberboard welding will be described.
Waste fiber products are a mixture of nylon, polyester, wool, and cotton. Waste fiber products mixed with miscellaneous materials are finely crushed into single fiber hairs, mixed with cellulose fiber hairs opened from wood scraps, stirred and mixed with each other, and then heated and pressurized. By pressing and compacting, a fiberboard in which miscellaneous waste fibers are mixed is obtained.

  A heating element is uniformly applied to any surface of the fiberboard. It is also possible to enhance the high-frequency attenuation effect by mixing a dielectric material such as nickel hydroxide, ethylene glycol, titanium, ferrite, tin oxide, copper, iron powder together with a heating element on the surface of the fiberboard. After the heating element is applied to the surface of the fiberboard, the process proceeds to fiberboard lamination or temporary assembly of the fiberboard and rib plate. For temporary assembly of rib plates, etc., manufacture temporary assembly jigs, etc. using materials with a low dielectric power factor such as micalex, muscovite, sulfite, quartz glass, etc. It is preferable to carry in to the next heating process with the temporarily assembled state.

  The high frequency heating includes high frequency dielectric heating performed in a frequency range of 1 MHz to 300 MHz and microwave heating performed in a frequency range of 300 MHz to 300 GHz. Microwave heating is advantageous in terms of facilities and versatility in that it can be arbitrarily laminated and welded without a specific electrode plate, but there is also a problem in that it lacks in terms of mass productivity. . However, as long as local heating is promoted by arranging the heating element in a high-frequency electric field, both microwave heating and high-frequency dielectric heating are the same, and both can be employed. Since each heating has characteristics, it is desirable to select any one depending on the structure and production amount of the structures to be welded. For example, microwave heating may be employed for a prototype experiment, and high frequency dielectric heating may be employed for mass production.

  After applying a heating element to the fiberboard, it is put into a heating furnace. For example, when two fiber boards are laminated and welded, a heating element is applied to the overlapping surface. Further, when a rib plate is welded to the fiber plate, a heating element is applied to a predetermined position of the fiber plate, the rib plate is disposed thereon, and is fixed with a clamp jig or the like (temporary assembly). In the heating furnace, a heating element including an aqueous glycerin solution is irradiated with a high-frequency output of 2.45 GHz to promote temperature rise and heating from inside the heating element. Due to the property of high-frequency heating that promotes local heat generation inside the heating element, only the heating element previously applied to the fiberboard is heated, and the fiberboard or rib plate is softened and melted indirectly.

  The fiberboard softened and melted in the heating furnace is then transferred to a compression / pressure molding process. In the compression / pressure molding process, a fiber board in which a laminated or rib plate is temporarily assembled is placed in the gap between the upper and lower molds, and is pressed and hardened by the applied pressure. Thereby, fiber boards or a fiber board and a rib board are pressed and solidified by the upper and lower molds, and welding and solidification are performed. Uses wood components derived from wood as a compatibilizing agent for the welding of fiberboards with mixed incompatible fibers such as nylon, polyester, wool, polypropylene, etc. By forming the heating element by impregnating with the glycerin aqueous solution, it is possible to carry out lamination welding of the fiberboards with suppressed generation of thermal strain.

  Residential materials are required to have physical strength in addition to functionality such as water resistance and heat insulation. Although fiberboard made of waste fiber products has excellent functionality in terms of water resistance, heat insulation, etc., there has been a major problem with insufficient physical strength. However, by welding a rib plate or the like to the fiberboard, it was possible to improve the physical strength such as deflection generated in the fiberboard. Fiberboard molded bodies with improved physical strength, that is, panels, are constructed with high seismic structures, such as so-called monocoque structures that integrate floors, walls, and roofing materials by joining the panels together. It became possible to do.

An example in which two fiberboards are laminated and welded for use as a floor base material will be described.
In recent timber housing structures, the occurrence of white ants and the occurrence of corrosion, rot, mold, mites, etc. have become major social problems. A fiberboard can be obtained from waste fiber products in which curtains, carpets, clothing, etc. are mixed. Fiberboard made from waste fiber products can be used as a housing material if the physical strength is improved without formaldehyde emission and the occurrence of corrosion, decay, mold and mites. In this example, a floor base material having excellent physical strength, water resistance, corrosion resistance and the like was manufactured by laminating and welding two fiberboards.

First, the heating element will be described.
The high frequency energy is absorbed by a substance having a large dielectric loss coefficient (εγ · tanδ) and promotes heat generation. The power per unit volume related to heat generation is proportional to the square of the electric field strength (E / d), the frequency f, the relative dielectric constant εγ, and the dielectric loss tangent tanδ. The product of the dielectric constant and the dielectric loss tangent is called the dielectric loss coefficient. The larger the dielectric loss coefficient, the better the heat generation. Water (25 ° C.) has a dielectric constant of about 77, but has a large specific heat of 1.0, requires a lot of heat energy, and has a low boiling point. Therefore, the temperature can be raised to a high temperature region by mixing with glycerin (C ₃ H ₈ O ₃ ) having a small specific heat and a high boiling point. Specifically, water (H ₂ O) was set to 5 with respect to glycerin (C ₃ H ₈ O ₃ ) 100 and stirred in a heated state at 60 ° C. to obtain a uniformly mixed glycerin aqueous solution.

Cedar thinning was used as a carrier to impregnate the heating element. Cedar thinned timber having a diameter of 250 mm and a length of 2000 mm was finely crushed to obtain a cedar crushed piece of about 50 mm. This cedar crushed piece was made into particles using a pulverizer (manufactured by Shinto Koki Co., Ltd., model SHM). The particle size was about 2.0 mm and the water content was about 8
% Of cedar particulate matter was obtained.
The cedar particulate matter was put into a vacuum pressure kettle, and the pressure was reduced to −0.6 atm while heating at a heating temperature of 110 ° C. for 20 minutes. With the heating and vacuum treatment of the vacuum pressure kettle, water remaining in the cedar particulate matter was evaporated, and the water content was reduced to 0.8% or less. The deceased and dried cedar particulate matter was mixed with glycerin (C ₃ H ₈ O ₃ ) 100 at a ratio of 5 (water ₂ ), and 5 cc of glycerin aqueous solution at a temperature of 60 ° C. The solution was put into a high-frequency attenuation solution tank and impregnated with the cedar particulate matter.

After stirring and mixing the cedar particulate matter in the high-frequency attenuation solution tank, the container is sealed, heated to 110 ° C., pressurized to 1.2 atmospheres, and heated and steamed for about 20 minutes. Boiling treatment was performed. As a result, the high-frequency attenuation solution is infiltrated deep into the central part of the cedar particulate matter. Since the cedar particulate matter is dehydrated and dried at a moisture content of 0.8% in advance, the high-frequency decay solution penetrates deep into the cedar particulate matter body by heating and boiling in the high-frequency decay solution. To do.
After the heating and steaming treatment, the cedar particulate matter was taken out of the container, drained and naturally dried to adjust the water content to about 30%. Thereafter, hot air at about 60 ° C. was given for 30 minutes to volatilize the high-frequency damping solution impregnated / impregnated into the surface layer, and only the surface layer of the particulate matter was uniformly dried, thereby adjusting the water content to about 15%. .
Thus, 500 g of cedar particulate matter having a high-frequency damping solution water content of about 15% was obtained. This cedar particulate matter is configured as a heating element carrier including a high-frequency damping solution deep in the central portion and having a dry surface layer.

As a fiberboard to be welded using the above-mentioned heating element, waste fiber products mixed with nylon, polyester, wool, etc. are bristled and pressed with heat and pressure to make them 13mm thick, 600mm wide, and length. Two 1800 mm fiberboards were obtained. If the fiberboard is used as it is as a floor base material, the physical strength is inferior and it cannot be used. Therefore, the physical strength is improved by laminating and welding the fiberboard. That is, the above-mentioned 500 g of cedar particulate material having a particle size of about 2.0 mm and a water content of glycerin aqueous solution of about 15% is applied as a heating element to the surface of the fiberboard to adjust the density to be uniform. Another fiberboard was laminated so as to sandwich the heating element applied to the surface of the fiberboard, and a structure in which two fiberboards were laminated was obtained.

Two layers of fiberboards laminated with a heating element interposed between the fiberboards were put into a heating furnace and subjected to microwave heating. Specifically, the heating element was heated to about 165 ° C. by irradiating a microwave with a frequency of 2.45 GHz for about 240 seconds. Due to the temperature rise of the heating element, the fiberboard was indirectly encouraged to soften and melt. As the temperature of the heating element increased, the surface of each fiberboard became softened and melted, and was welded together by applying pressure. Specifically, two fiberboards having a thickness of 13 mm were subjected to compression and pressure molding at 25 kg / cm ^{2 to} form an integrated laminated fiberboard having a thickness of 25.5 mm.

Conventional wood-based laminated wood such as veneer plywood and particle board is inferior in water resistance and corrosion resistance, and has a problem of bending strength when wet. In particular, floor base materials and the like are high in moisture, and have a great social problem with high moisture content and aged deterioration. However, the wet bending strength is improved by laminating and welding the fiberboards. As a specific example, the strength was improved to 28.7 N / mm ² by laminating and welding the bending strength of a single fiberboard of 15 N / mm ² .
Further, while aged deterioration of veneer plywood, particle board, etc. was confirmed, 5040 H was measured for a moisture content of 25%, and as a result, the wet bending strength of the fiberboard secured 26.6 N / mm ² .

It is a welding process figure of the fiber board which shows embodiment of this invention. It is typical sectional drawing of a heat generating body. It is a manufacturing-process figure of the glycerol aqueous solution which comprises a heat generating body. It is a manufacturing-process figure of the heat generating body which carry | supported the glycerin aqueous solution to the wood chip. It is a welding process figure of a fiber board. It is a graph which shows the comparative test result of bending strength at the time of wetness.

Claims (8)

  After applying a heating element made of a dielectric on the surface of the first fiberboard, and superposing it on the second fiberboard, it is placed in a high-frequency electric field to promote softening and melting of the surface layer of the fiberboard, and then A method of welding fiberboards integrated by applying pressure molding.   The method of claim 1, wherein the heating element is a liquid and is impregnated with a wood material.   The method of claim 2, wherein the liquid is an aqueous glycerin solution.   The method according to claim 2 or 3, wherein the wood material is particulate or fibrous wood waste.   5. The method according to claim 4, wherein the wood chips are subjected to vacuum and heat treatment, then impregnated with an aqueous glycerin solution, and again subjected to pressure and boiling treatment.   The method according to any one of claims 1 to 5, wherein the first fiberboard and the second fiberboard are rectangular panels having the same shape.   The method according to any one of claims 1 to 5, wherein the first fiberboard is a rectangular panel and the second fiberboard is a rib plate.   A fiberboard welded by the method of any one of claims 1 to 7.

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