JPH0872019A - Stabilizing method for percentage of water content of wood-based material and manufacture of flush structural material - Google Patents

Abstract

PURPOSE: To prevent a flush structural material from being warped without changing the percentage of water content of a wood-based material, by a method wherein one side or both the sides or the whole surface of a wood-based material is coated and impregnated with flow paraffin until the balanced percentage of water content is attained. CONSTITUTION: After face materials 1, 2 and/or a core material 4 comprised of a wood-based material of a flush structural material and one side or both the sides or the whole surface is coated and impregnated with flow paraffin, the face materials 1, 2 and core material are stuck together with an adhesive agent and made into the flush structural material. On this occasion, a quantity of impregnation of the flow paraffin is made not exceeding 5% of weight of a treated material. The material is coated and impregnated with the flow paraffin like this so that the balanced percentage of water content is not changed and a difference in dimensional change by mutual moisture absorption is made little, through which the flush structural material is prevented from being warped.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for manufacturing a flash structure material using a face material made of a wood-based material such as MDF (medium density fiber board). Liquid paraffin is applied to prevent changes in the water content of the wood material, or a urea resin adhesive is applied to the entire surface to be bonded, and the product is attached by hot pressing under specific conditions. The present invention relates to a method for stabilizing the water content of a wood-based material that prevents warping of a flash structural material and a method for manufacturing a flash structural material.

[0002]

2. Description of the Related Art Wooden doors used for furniture, system kitchens, etc. have a structure of cutting and assembling from a traditional solid wood or laminated wood into a predetermined shape, and nowadays, a frame material, a core material, a decorative board and various other materials. Doors with a wooden flash structure that are formed by sticking flat plates, etc. are often used. The wooden flash structure used for such furniture doors and panels is made by attaching a thin flat plate to the surface of the core material. MDF (Medium Density Fiberboard) has been used.

Generally, a fiberboard (a fiberboard including wood, a fiberboard using a plant fiber other than wood), or a wood-based material having a water content in its fiber structure is subject to changes in ambient temperature and humidity. , The amount of water that can be contained in the tissue changes. Due to this change in water content (water content), the wood-based material is cracked, bent, or warped. In order to stably maintain a wood-based material product in a natural environment, it is necessary to include moisture in the fiber structure so as to maintain equilibrium with the environment. This is called equilibrium water content.

In order to make the wood-based material have an equilibrium water content, the product is conventionally made to contain water, left to stand, and used after the product has stabilized its water content. However, since the water content in the fibrous tissue changes due to changes in ambient temperature and humidity, it takes time to achieve the prescribed equilibrium water content, while the equilibrium water content changes due to a sudden change in the surrounding environment. There is a problem that I can not follow,
Traditionally, water in the fibrous tissue was considered to be an unstable element. For example, the above-mentioned MDF has a relatively small amount of synthetic resin for molding a fibrous material, so that the MDF at 50 ° C.
It is known that when left in a high temperature and high humidity of 10%, the size is clearly increased due to an increase in water content.

[0005]

In order to manufacture the above flash structure material, a face material is adhered to a core material. Conventionally, a vinyl acetate or urea resin adhesive containing water is used and both are When compressing and adhering, the two methods used were hot pressing, which applies heat, and cold pressing, which is simply compression. It is well known that, regardless of which construction method is adopted, the occurrence rate of warpage of the finished flash structure product is different when the weather during manufacturing is fine and when it is rainy.
It is considered that this is because the difference in the humidity of the atmosphere is directly reflected in the wooden material.

Therefore, the wood-based material for manufacturing the flash structural material is not affected by atmospheric humidity and temperature,
This problem will not occur if the prescribed water content is maintained at all times, but no method has been proposed for preventing fluctuations in the water content and stabilizing it. Further, for example, it is known that even if the water content of the wood-based material before bonding is stable in the equilibrium state, it may change a little during bonding and thereafter, which also leads to the occurrence of warpage of the flash structure product. The occurrence of warpage was increased with the weather at the time of bonding.

In view of the occurrence of warpage and peeling of the completed flash structure material, the present invention is applicable to various solid wood materials such as natural solid wood, laminated wood, veneer wood and other layered materials, and MDF and other fiberboard materials. The purpose of the present invention is to provide a method for stabilizing the water content of a wood-based material that can always stabilize the water content in an equilibrium state. In addition, when manufacturing a flash structure material using a face material made of MDF, etc. It is an object of the present invention to provide a method for manufacturing a flash structural material that can prevent warpage of a completed flash structural material without changing the rate.

[0008]

Means for Solving the Problems As a result of various studies aimed at a structure capable of always stabilizing the water content of a wood-based material in an equilibrium state, the water content of an essential material changes depending on climatic conditions. However, due to this, warpage occurs in the case of the flash structure, but since the water content of the wood-based material usually changes around 5%, it is necessary to add water corresponding to this water content in advance. However, when a substance that functions like water in wood-based materials and that does not easily evaporate under normal atmospheric temperature and humidity changes was examined, liquid paraffin was stable as a liquid in an environment around living environment temperature. It is easy to permeate just by applying it to the essential material, and then the permeated amount is stable without change or deterioration.
Further, they have found that they are highly safe, can use a water-based adhesive, and do not affect the current construction methods such as adhesion, and completed the present invention.

That is, the present invention is a method for stabilizing the water content of a wood-based material, which comprises coating and impregnating one or both surfaces or the entire surface of the wood-based material with liquid paraffin until an equilibrium water content is reached. The present invention also proposes a method for stabilizing the water content of a wood-based material in which the impregnated amount of liquid paraffin is 5% or less of the weight of the material to be treated in the above configuration.

In addition, as a result of various examinations by the inventor of the conventional bonding method at the time of manufacturing a flash structural material, that the water content of the wood-based material fluctuates to some extent after the bonding, it is found that the bonding when the water-based adhesive is used Focusing on the fact that the water contained in the agent migrates to the wood-based material side and causes warpage,
At least after applying and impregnating liquid paraffin to the surface where the adhesive is to be applied, by applying and bonding the adhesive,
The present invention has been completed by finding that liquid paraffin permeates the wood-based material to reach an equilibrium water content and prevent the water contained in the adhesive from migrating to the wood-based material.

That is, according to the present invention, liquid paraffin is applied and impregnated on one side or both sides or the entire surface of a face material and / or a core material made of a wood-based material for a flash structure, and then the face material and the core material are Is adhered with an adhesive, which is a method for manufacturing a flash structure material. Further, the present invention also proposes a method for producing a flash structure material in which the impregnation amount of liquid paraffin is 5% or less of the weight of the material to be treated in the above configuration.

Furthermore, when a method for preventing the water contained in the adhesive from migrating to the wood-based material side was examined, the adhesive is usually applied to the face material only on the adhesive surface with the core material. Or, the adhesive is applied only to the core material, but if the material is heated to 80 ° C to 90 ° C and the urea resin adhesive is applied to the entire surface of the face material to be bonded and hot pressed, the adhesive is applied. The moisture contained in the agent was evaporated by hot pressing, and after carrying out the hot press, the product was turned upside down, and the evaporated moisture was diffused evenly on the front and back sides, so that it was trapped inside the flash structure material. When water vapor is transferred to the face material, it can be evenly transferred, and the urea resin adhesive applied to the entire surface of the face material to be bonded functions as a barrier after curing, and resin etc. is laminated on the surface of the face material. Has been Without varying trapped moisture in the surface material if, also, if there is no such surface treatment by excess moisture in the interior during the cooling is dissipated,
The present invention has been completed by finding that the warp of the flash structure material can be prevented.

That is, according to the present invention, a urea resin adhesive is applied to the entire surface to be bonded of a face material made of a wood-based material for a flash structure, and at least the adhesive portion of the face material is 8
It is a method for manufacturing a flash structural material, which comprises heating to 0 ° C. to 90 ° C. and hot pressing, and inverting the front and back of the flash structural material after adhesion and cooling the same. Further, according to the present invention, in the above structure, heating is performed by a high frequency induction heating method, a press roller is used, and a pressure of 2 kg.
We propose a method for manufacturing a flash structural material in which hot pressing is continuously performed from one direction to the other at a pressure of less than 1 cm ² / cm ² . Also,
According to the present invention, in the above structure, a high-frequency induction heating electrode is arranged so as to face each surface material so that electromagnetic waves are generated in the front-back direction of the surface material, and a flash structure material configured not to oscillate even if there is a metal material inside the material. The manufacturing method of is proposed. Further, the present invention also proposes a method for manufacturing a flash structure material in which the electrodes for high frequency induction heating in the above structure are arranged so as to be inclined with respect to the transverse direction of the traveling direction of the rectangular material, and the heating is made uniform.

[0014]

The operation of the present invention will be described in detail below with reference to the drawings. As shown in FIG. 1, the rectangular frame member 3 is sandwiched between the face members 1 and 2.
As a cause of the warp in the flash structure material having the cross-sectional structure in which is arranged, for example, even if the face material 1 and the face material 2 are the same material, the change in the equilibrium water content may differ depending on the surrounding environment. Therefore, the dimensional changes of the face material 1 and the face material 2 are different accordingly. That is, if the face material 1 absorbs more moisture than the face material 2, the length of the face material 1 naturally becomes the length of the face material 2
It becomes longer than that, and it inevitably bends toward the face material 1 side. As a measure to prevent warpage due to changes in atmospheric temperature and humidity, it is naturally conceivable to reduce the dimensional changes of the face materials 1 and 2, but in the present invention, liquid paraffin is applied and impregnated so as not to change the equilibrium water content. , To prevent warpage by reducing the difference in dimensional change due to mutual moisture absorption.

In the present invention, the reason why liquid paraffin is used as a substitute for water in the fiber tissue is that the liquid paraffin easily infiltrates into the fiber tissue, does not chemically affect the fiber tissue, Since it is very stable as a liquid in the environment and has no compatibility with water, if it is infiltrated as a substitute for water in the fibrous tissue,
This is based on the finding that liquid paraffin staying in the inside in a constant state irrespective of changes in the temperature and humidity of the atmosphere and liquid paraffin in the fiber structure can prevent moisture from entering the fiber structure.
In addition, the water content of essential materials changes depending on the climatic conditions, but the change in water content is usually about 5% under normal environment, so the liquid paraffin impregnation amount is limited to 5% of the product weight in advance. By infiltrating the liquid paraffin into the fibrous tissue, it is possible to prevent the dimensional change due to the absorption and drainage of water in the fibrous tissue.

In the present invention, the liquid paraffin refers to one having no wax content in the paraffin, which is stable as a liquid in a normal living environment and has no compatibility with water, but has a low boiling point of 50. The boiling point is preferably 70 ° C. or higher, and most preferably 100 ° C. or higher, although those having a temperature of 60 ° C. to 60 ° C. can be used. The average molecular weight is 320 to 38.
A value of about 0 is desirable.

To apply and impregnate various essential materials such as natural solid wood, laminated wood, layered wood such as veneer wood, and fiberboard such as MDF with liquid paraffin, the shape and size of the plate or bar, or the surface Processing form of
That is, one surface, both surfaces or the whole surface is applied and impregnated according to the surface cosmetic material or coating, but the surface materials 1 and 2 of the flash structure material of FIG. Liquid paraffin can be applied and impregnated on the surface to be bonded to the frame member 3. Further, liquid paraffin does not necessarily have to be uniformly impregnated into the whole of the essential material, and unless a cosmetic material is attached to the one main surface and the end surface to absorb and release moisture from the same surface, for example, On the other hand, if liquid paraffin is impregnated and stays inside the material near the surface of the other main surface, the amount of water contained in the essential material will not change. Of course, the water content is not changed by impregnating liquid paraffin inside the material near the entire surface of the essential material.

In manufacturing the flash structural material, at least the entire surface of the face material to be bonded is coated and impregnated with liquid paraffin, and then the face material and the core material are adhered with an adhesive, for example, When a water-based adhesive such as vinyl acetate or urea resin is used in consideration of safety, the moisture inside the adhesive does not move to the side of the face material and the water content of the face material does not change. In this case, liquid paraffin may be applied and impregnated on both sides or the whole of a face material having no resin layered or decorative material on the surface side, and further, one or both sides or the whole surface of the core material may be applied and impregnated with liquid paraffin. It is also possible to set it. The impregnated amount of liquid paraffin is preferably 5% or less of the weight of each face material or core material. Also, after applying and impregnating liquid paraffin on the surface to be bonded,
Immediate application of the adhesive does not cause any inconvenience to the liquid paraffin impregnation or the adhesive itself.

In the production of the flash structural material, liquid paraffin is applied to the entire surface of the essential material, or liquid paraffin is applied to the surface on which the decorative material is not provided to provide a barrier against moisture on the surface, so-called essential material. The purpose is not to absorb and remove water by breathing, but the same action and effect can be obtained by using a urea resin adhesive. When a flash structural material is manufactured using a urea resin adhesive containing water, in order to prevent warpage due to such water, hot pressing under specific conditions
It is effective to eliminate excess water. That is,
Apply urea resin adhesive to the entire surface of the face material to be bonded, heat the bonded part of the face material to 80 ° C to 90 ° C and hot press it. Is reversed and cooled.

In the method of manufacturing a flash structural material according to the present invention, the urea resin is used as an adhesive and is applied over the entire surface. This is because it is possible to prevent the moisture inside the structural material from affecting the water content of the face material. Also, adopting hot press is
For the purpose of reducing the effect on the surface material due to the moisture of the adhesive being heated and vaporized, first, the moisture contained in the adhesive is evaporated by hot pressing, and the moisture is diffused into the atmosphere. In addition, there are some that enter inside the face material before the curing of the urea resin and some that are trapped inside the flash structure material.

The water content in the surface material has an increased water content because the material to be treated is heated to 80 ° C. to 90 ° C. No warpage occurs due to this, and the surface of the equilibrium surface material If the side is not treated with makeup, it is diffused into the atmosphere from the surface when it is cooled, and if the face is treated with makeup, it is sandwiched between the cured urea resin layer on the adhesive side and the face material. However, it cannot be breathed and is trapped, but the warp does not occur. Also, the reason why the obtained flash structure material is turned upside down during cooling after hot pressing is to equalize the water content of the face material, and the interior of the flash is filled with heated air. Since the upper surface side is heated by the air and the lower surface side is dried by heating, it is effective to turn the surface material upside down during cooling in order to equalize the heating conditions of the surface material.

In the manufacturing method of the present invention, the heating temperature of the bonded portion of the material to be treated is set to 80 ° C. to 90 ° C. When the temperature is less than 80 ° C., an aqueous emulsion type vinyl acetate adhesive or urea resin adhesive is used. It takes time for the coins of the agent, and the mass production effect decreases. Further, when the temperature exceeds 90 ° C, the directly heated parts other than the bonded part are heated to 100 ° C or more. In this case, the molecular weight of cellulose, which is the main constituent of the wood-based material, is lowered and the strength is lowered. This is because it is not preferable.

When manufacturing the flash structural material, hot pressing may be performed by a conventional flat press under the above conditions. However, in the present invention, in order to realize continuous hot pressing, a high frequency induction heating method is used. It is proposed to heat and hot press using a press roller at a pressure of 2 kg / cm ² or less. As shown in FIG. 2, this is performed by pressing the entire flash structure material 10 with the press rollers 11 and 12.
Since the adhesive is sequentially and continuously applied from one end to the other end, there is an advantage that internal stress at the time of curing does not easily remain as compared with the conventional simultaneous full-surface adhesion by a flat press. In addition, 13 in the figure
Is an electrode and 14 is a feed roller. Here, the pressure of the press rollers 11 and 12 at the time of hot pressing is 2 kg /
If it exceeds cm ² , the face material may be deformed in the part without the core.

Further, in order to realize continuous high frequency hot pressing, as shown in the embodiment, the anode and the cathode of the high frequency induction heating electrode are arranged as shown in FIG. 2 so that electromagnetic waves are generated in the front-back direction of the surface of the face material. Even if there is, for example, a core positioning metal material inside the material, it is configured not to oscillate. Furthermore, by arranging the anode and cathode of the electrode in the front-back direction of the face material surface in the figure, for example, the upper electrode functions for curing the aqueous adhesive between the facing face material and the core, Similarly, since the lower electrode functions to cure the water-based adhesive between the facing surface material and the core, the current applied to the electrode can be controlled so that individual curing conditions can be set for each of the front and back surfaces. There are advantages.

Further, in the present invention, as shown in the embodiment, the high frequency induction heating electrode is arranged to be inclined with respect to the transverse direction of the traveling direction of the rectangular material, which is for uniform heating. As shown in FIG. 3B, conventionally, since the electrodes 15 are arranged in the transverse direction of the traveling direction of the material, the core material 6 particularly in the transverse direction of the rectangular frame 5 is selectively heated. As indicated by A, by arranging the rectangular frame 5 so as to be inclined from the transverse direction in the traveling direction, there is an advantage that the entire rectangular frame 5 is uniformly heated. The inclination angle is especially 4 in the case of the flash structure material in which the core material of the rectangular frame is used.
The range of 5 ° ± 10 ° is desirable and can be appropriately selected according to the short side / long side ratio of the rectangular frame.

[0026]

【Example】

Example 1 The following three types of MFD single plates (200 × 200 × 2.5 mm
(Cut out to size), and place the MFD veneer on a resin table that is impermeable to moisture, and at -20 ° C x 8
The size of the veneer was examined after two cycles of atmosphere change from extremely low temperature to high temperature and high humidity at 50 ° C. and 95% × 12 hours. 1) Liquid paraffin (boiling point 182 ° C.) applied and impregnated on both sides of the plate until the equilibrium water content is reached (Invention 1), 2) Liquid paraffin (boiling point 182 ° C.) applied on one side, and the coated side What is placed on the table above (the present invention 2), 3) What has gone through a normal commercial transaction route after manufacturing (conventional). The dimensional change is 0.1 to 0.
15% and 0.25 to 0.35% in the widthwise direction of the original plate, while both Invention 1 and Invention 2 have 0.02 to 0.05% in the longitudinal direction of the original plate and shortness of the original plate. 0.1 toward hand
It is ~ 0.2%, and it can be seen that the dimensional change is small.

Example 2 A flash structural material having a cross-sectional structure in which the surface materials 1 and 2 are arranged with the rectangular frame member 3 sandwiched in FIG. 1 and a paper honeycomb core member 4 is inserted into the rectangular frame member 3 is provided. The manufacturing apparatus according to the present invention shown in FIG. 4 was used for manufacturing. More specifically, the conveyor line is sandwiched from the beginning of the line to the center, and two more conveyor lines are provided side by side. In the figure, the upper side of the central α line is the β line and the lower side is the γ line, and the β line is the rectangular frame member 3 , Α line is the face material 2 for the back surface made of MFD, γ
The line is a conveyor line that conveys the surface material 1 made of MFD.

The surface materials 2, 1 for the α line and the γ line are placed on the conveyor with the surface to be bonded facing up and the adhesive is applied by the roll coater 20. Here, liquid paraffin is applied to the surface to be bonded. Immediately after applying, the urea resin adhesive is applied on the liquid paraffin. After exiting the roll coater 20, liquid paraffin is applied to each face material 2, 1
Immediately impregnate the surface to be adhered with, and the adhesive remains on the surface. At the next stage, the rectangular frame material 3 is moved and placed on the back surface material 2 for the α line, the paper honeycomb core material 4 is further loaded into the rectangular frame material 3, and then the surface of the γ line. The face material 1 for use is inverted and moved and placed on the rectangular frame material 3 of the α line, and the flash structure assembly 7 before bonding is completed.

The flash structure assembly 7 is inserted into the high-frequency heating roller press 22 having the same construction as shown in FIG. When the assembly 7 is turned on by the high frequency power supply 23, the face material itself is heated to about 85 ° C. and pressure-bonded with a press roller at a pressure of 1.5 kg / cm ² , and then inverted by a carry-out conveyor 24. It is sent to the machine and placed on a table with the face material for the back side, which was the lower side at the time of crimping, facing up, and allowed to cool.

The MDF manufactured by Bivan (Italy) is used.
The dimensions are 696 mm × 446 mm × 2.5 mm, the front side is a dup sticking specification, the back side is a print sheet sticking specification, and the rectangular frame material is a particle board with a thickness of 12 mm. Manufactured. In the case of the present invention, as described above, liquid paraffin is applied to the entire surface to be adhered, immediately after the urea resin adhesive is applied on the liquid paraffin, hot pressing is performed with a high-frequency power source, and the front and back are inverted and then released. Although it is a cooling step, in the step of the comparative example, the urea resin adhesive was applied only to the adherend surface without applying liquid paraffin, and adhesion was performed by a conventional cold press. -20 ° C x 8 for various door products obtained
A heat cycle test was performed to evaluate the amount of warpage after 7 cycles of changing the atmosphere from an extremely low temperature to a high temperature and high humidity state for 50 hours to 50 ° C. and 95% × 12 hours. The results are shown in Table 1.
Shown in In addition, a heat resistance test was carried out to evaluate the amount of warp after continuously holding at 50 ° C. for 7 days. The results are shown in Table 2.

In the case of the MDF manufactured by Bivan Co., Ltd., which is sensitive to humidity changes in Japan and is extremely likely to warp, as shown in a comparative example by a conventional cold press, there is not much difference in the heat resistance test, but the allowable range in the heat cycle test. Absolute value easily exceeds 1mm, not shown here, but 10
Warpage occurs with a probability of 0%. If the absolute value in the above heat cycle test exceeds 1 mm, the door of such furniture is recognized as a clear surface step and has no commercial value, and if this is converted into the door size of the room, the door latch will not close. Equivalent to a degree of warp. On the other hand, when liquid paraffin is applied, hot pressing is performed with a high frequency power source, the front and the back are reversed and the product is allowed to cool, the total amount is within an allowable absolute value of 1 mm or less. Even when compared with Example 4, the variation was small.

[0032]

[Table 1]

[0033]

[Table 2]

Example 3 In Example 2, a Japanese product (manufactured by Hokushin Co., Ltd.), which is insensitive to changes in humidity, was used as the MDF. In the present invention example, liquid paraffin was applied and a urea resin adhesive was applied only to the surfaces to be bonded. After coating, they were bonded by a conventional cold press. Further, in the process of the comparative example, liquid urea was not applied, and the urea resin adhesive was applied only to the surfaces to be adhered, and then the conventional cold press was applied. Example 2 on the obtained door
When a heat cycle test was performed under the same conditions as above, more than half of those without applying liquid paraffin had an allowable value of 1 m.
In contrast to the value exceeding 1 m, the total number of the present invention was less than the allowable value of 1 mm.

Example 4 In Example 2, a product made in Japan (made by Hokushin Co., Ltd.), which is insensitive to humidity change, was used as the MDF, and in the example of the present invention, a urea resin system was applied to the entire surface to be adhered without applying liquid paraffin. After applying the adhesive, hot pressing by resistance heating, inverting the front and back and letting it cool, and carrying out two methods of the hot pressing only hot pressing with a high frequency power supply, In the conventional process, the liquid paraffin was not applied, and the urea resin adhesive was applied only to the surfaces to be bonded, and then the conventional cold press was used for bonding. When the obtained door was subjected to a heat cycle test under the same conditions as in Example 2, more than half of those obtained by the conventional cold press exceeded the allowable value of 1 mm, while the hot press of the present invention is The total number of steps was less than the allowable value of 1 mm. Therefore, in the above-mentioned conventional example, before the cold pressing, the humidity control step of arranging the face materials side by side with water and leaving it for several days was necessary, but according to the present invention, there is an advantage that the humidity control step is unnecessary.

Example 5 The high frequency hot pressing apparatus shown in FIG. 5 has a structure capable of continuously hot pressing flash structural materials.
A flash structure assembly is sandwiched between a pair of belt conveyors 30 and 31 and can be fed, and high-frequency induction heating electrodes 32 and 33 are arranged so that electromagnetic waves are generated in the front-back direction of the surface material.
Are arranged at predetermined intervals in the belt conveyors 30 and 31 so as to face each face material, and the electrodes 32 and 33 are arranged to be inclined by 35 ° from the transverse direction of the traveling direction of the rectangular material. Further, a plurality of non-driving rollers 35 are arranged at a predetermined interval in the lower belt conveyor 31, and the rollers are also arranged in the upper belt conveyor 30 so as to form a pair with the non-driving rollers 35. Is constituted by an air press roller 34 capable of pressing at a predetermined pressure, here 1.0 kg / cm ² .

The upper electrode 32 is used for curing the water-based adhesive between the facing material and the core, and the lower electrode is similarly used for curing the water-based adhesive between the facing surface material and the core. Then, individual curing conditions were set for each of the front and back. That is, it is intended to cope with a change in curing condition due to a difference in the amount of the water-based adhesive applied for adhering the upper and lower facing surface materials and a difference in the high frequency condition setting due to a difference in the material of the facing surface material. Further, the high frequency hot pressing apparatus shown in FIG.
The 33 arrangement has an advantage that even if there is a core positioning metal material inside the material, it does not oscillate and the entire rectangular frame is uniformly heated.

Implementation No. 2 in Embodiment 2 1-No. Four
Since each door has a dup sticking specification for the front side and a print sheet sticking specification for the back side, as shown in Table 3, the water content greatly differs between the front side and the back side. That is, since the water content on the front surface side that has been dapped is high, the same power is applied to the front and back surfaces in the conventional electrode arrangement that allows electromagnetic waves to pass between the front and back surfaces, and the front surface side is quickly heated and cured, and then the back surface side is cured. Although it does not immediately cause warpage in the heat cycle test of Example 2, it greatly affects the deformation and strength after long-term aging. Therefore, by using the high-frequency hot pressing apparatus shown in FIG. 5, the front surface and the back surface can be heat-cured simultaneously by decreasing the power on the front surface side or increasing the power on the back surface side to adjust the temperature. Deformation can be prevented. In terms of steps, it is most desirable to adopt the configuration of FIG. 5 in which the electrodes are arranged on the surface side of the face material in the high frequency hot press of Example 2 and to adjust the power between the front and back sides.

[0039]

[Table 3]

[0040]

The present invention is characterized in that a wood-based material is coated and impregnated with liquid paraffin until an equilibrium water content is reached, which is stable as a liquid in an environment where liquid paraffin is at a living environment temperature. In addition, it utilizes the property that it easily penetrates by simply applying it to the essential material.The amount that penetrates is stable without fluctuation and deterioration, it is highly safe, and an aqueous adhesive can be used. The water content of the wood-based material can be always stabilized in an equilibrium state without affecting the current construction method such as adhesion.

Further, in the method for manufacturing a flash structure material according to the present invention, the wood-based material is heated to 80 ° C. to 90 ° C., the urea resin adhesive is applied to the entire surface of the face material to be bonded and hot pressed. Then, the moisture contained in the adhesive is evaporated by hot pressing, and after carrying out the hot press, the product is turned upside down so that the diffusion of the evaporated moisture is evenly spread to the inside and outside of the flash structure material. The trapped water vapor can be transferred evenly when it moves to the face material, and the urea resin adhesive applied to the entire surface of the face material to be bonded functions as a barrier after curing, and the resin on the surface of the face material If the surface is laminated, the moisture in the face material is not trapped and changed.If such surface treatment is not performed, excess moisture inside is diffused during cooling, resulting in a Warping of Interview structural material can be prevented.

Further, even in the case of a flash structure material using MFD which is sensitive to humidity change and which is extremely likely to warp in Japan, liquid paraffin is applied to the entire surface to be bonded immediately after the liquid paraffin is applied to the urea resin system. After applying the adhesive, hot pressing with a high frequency power supply can be performed to reverse the front and back and allow to cool, and the warp can be significantly reduced.As is clear from the examples, even if the total warp exceeds the standard in the conventional method. In the present invention, the warp can be suppressed so that the total amount is within the standard.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a flash structure material.

FIG. 2 is an explanatory view showing a hot pressing process according to the present invention.

FIG. 3 is an explanatory view showing a high frequency induction heating method according to the present invention.

FIG. 4 is an explanatory diagram of a flash structural material manufacturing apparatus according to the present invention.

FIG. 5 is an explanatory view of a hot press device by high frequency induction heating according to the present invention.

[Explanation of symbols]

 1, 2 surface materials 3 rectangular frame material 4 paper honeycomb core material 5 rectangular frame 6 core material 7 flash structure assembly 10 flash structure material 11, 12 press roller 13 electrode 14 feed roller 15 electrode 20 roll coater 21 insertion conveyor 22 Roller press 23 High frequency power supply 24 Carry-out conveyor 30,31 Belt conveyor 32,33 Electrode 34 Air press roller 35 Non-driving roller

Claims (8)

[Claims] 1. A method for stabilizing the water content of a wood-based material, which comprises coating and impregnating one or both surfaces or the entire surface of the wood-based material with liquid paraffin until an equilibrium water content is reached. 2. The method for stabilizing the water content of a wood-based material according to claim 1, wherein the impregnated amount of liquid paraffin is 5% or less of the weight of the material to be treated. 3. A liquid paraffin is applied and impregnated on one side or both sides or the whole surface of a face material and / or a core material made of a wood-based material of a flash structure material, and then the surface material and the core material are used as an adhesive. A method for manufacturing a flash structure material, which comprises applying the flash structure material. 4. The method for producing a flash structural material according to claim 3, wherein the impregnated amount of liquid paraffin is 5% or less of the weight of the material to be treated. 5. A urea resin adhesive is applied to the entire surface to be bonded of a face material made of a wood-based material of a flash structure material, and at least the bonded portion of the face material is heated to 80 ° C. to 90 ° C. and hot pressed. Then, the method for producing a flash structural material is characterized in that the flash structural material after adhesion is cooled by reversing the front and back from the time of hot pressing. 6. The method for producing a flash structural material according to claim 5, wherein the flash structural material is heated by a high frequency induction heating method and hot-pressed with a press roller at a pressure of 2 kg / cm ² or less. 7. The method for manufacturing a flash structure material according to claim 6, wherein high-frequency induction heating electrodes are arranged facing each surface material so that electromagnetic waves are generated in the front-back direction of the surface material. 8. The method for manufacturing a flash structural material according to claim 7, wherein the high-frequency induction heating electrode is arranged so as to be inclined with respect to the transverse direction of the traveling direction of the rectangular material.