JPH0433241B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention comprises plywood by alternately stacking a predetermined number of original boards and core boards coated with thermosetting adhesive, and laminating a large number of such plywood boards. The present invention relates to a method of manufacturing plywood by bonding an original board and a core board together by pressing and heating the same at the same time.

(Conventional technology) In conventional plywood manufacturing methods, when using urea-based resin adhesive as the adhesive to bond the original board and core board, the adhesive must be heated to about 100°C to harden and stick, so it is cold-pressed using a cold press. We use a method of temporary adhesion and then heat pressing using a hot press. That is, several dozen sheets of plywood A made up of a combination of an original board and a core board coated with a thermosetting adhesive are laminated, and this is transported and inserted into a cold press machine (not shown) and pressed for a predetermined period of time. The original board and the core board are temporarily bonded, and then the temporarily bonded plywood is inserted one by one between the hot platens 21 of the hot press device 20 shown in FIG. 7, and then pressed by the press device 20 and hot pressed. A steam header 2 is attached to each heating plate 21 of the device 20.
2, steam is supplied and heated to harden and fix the adhesive, and the original plate and the core plate are bonded together to form plywood. After the bonding is completed, this plywood is taken out from between each hot platen 21 of the hot press device 20 and subjected to the next finishing. Plywood is manufactured by transporting it to the process.

(Problems to be Solved by the Invention) In the conventional plywood manufacturing method described above, a hot press machine equipped with a large number of hot plates heated with steam is used for hot pressing, which requires a large amount of equipment costs. In addition, it is necessary to insert and remove heavy plywood one by one between each hot platen of the hot press machine, and it is difficult to automate the insertion and removal of non-standard plywood, thick plywood, curved plywood, etc. This method had the disadvantage of low work efficiency as it had to be done manually. Furthermore, since the heating plate has a structure in which steam pipes are arranged inside, it is difficult to uniformly heat the plywood over the entire surface, and temperature control is also difficult. Moreover, when making curved plywood, it is necessary to make a hot plate that matches the curved surface to be formed.
Therefore, there were problems such as the inability to form curved plywood using the hot press apparatus shown in FIG.

This invention was created in view of the above points, and uses a planar heating element made of flexible fluororesin (conductive tetrafluoroethylene resin), etc.
During the so-called cold press process, in which the plywood layers are compressed and temporarily bonded using a press machine, heating is performed at the same time.
The object of the present invention is to provide a plywood manufacturing method in which a cold press step and a hot press step are performed at the same time, and the hot press step is omitted using a so-called hot press device in which a heating device is incorporated in the press device, and the original board and the core board are bonded together. .

(Means for Solving the Problems) The present invention solves the above problems, and includes an original board 1 and a core board 2 coated with a thermosetting adhesive 3.
Plywood A is constructed by stacking a predetermined number of sheets alternately.
When stacking the plywood A, a sheet heating element 4 having flexibility and having a terminal 5 for connecting a power source is sandwiched between the plywood A and the laminated surface. The plywood layers sandwiching the shaped heating elements 4 are transported and inserted as they are into the press device 6, and are pressed by the press device 6. At the same time, each of the sheet shaped heating elements 4 sandwiched between the plywood layers is connected to a power source through the terminals 5, and is connected to a power source at a predetermined position. Electricity is applied for a period of time to cause the planar heating element 4 to generate heat at a desired temperature to heat and harden the thermosetting adhesive 3, thereby bonding the original plate 1 and the core plate 2.

(Function) With the above configuration, plywood A is constructed by alternately stacking original boards 1 and core boards 2 coated with adhesive 3, and the plywood boards A are stacked one after another. At this time,
A sheet heating element 4 is sandwiched between plywood A and plywood A with the terminal 5 protruding at a predetermined position to form a plywood layer with the sheet heating element 4 sandwiched therebetween, and this plywood layer is passed through a press machine 6 as it is. The material is transported to a press table, inserted and placed on a press table, and then compressed by the press device 6. Then, a power source is connected to the terminals 5 of the sandwiched sheet heating elements 4, and the electricity is turned on for a predetermined period of time. As a result, the planar heating element 4 generates heat and evenly heats the entire surface of the plywood.
The thermosetting adhesive 3 is heated and cured through the front and back original plates 1 to bond the original plate 1 and the core plate 2 together. After the adhesion is completed, the laminated plywood layers are taken out from the press device 6 and transported to the next finishing process with the planar heating element 4 sandwiched between them. When inserted into the finishing process, the planar heating element is separated from the plywood A'. to be collected and reused.
Plywood A′ is cut and surface-finished in the finishing process.

(Example) The plywood manufacturing method according to the present invention will be explained below based on the drawings.

In general, plywood is a veneer in which the fiber direction is in the longitudinal direction as the original board 1, and the one in which the fiber direction is perpendicular to the fiber direction of the original board 1 is called the core board 2. Both sides of the core board 2 are coated with urea resin, etc. A thermosetting adhesive is applied using a spreader, and a predetermined number of base plates 1 and core plates 2 are alternately overlapped to form plywood A. When manufacturing a 3-ply plywood as shown in FIG. Prepare two sheets of heating element 1, then one sheet of sheet heating element 4, and apply urea resin adhesive 3 to both sides of the core plate 2 through a spreader.
The core plate 2 is layered on top of the previous base plate 1, and the two base plates 1 with the planar heating element 4 sandwiched therebetween are stacked on top of each other, and then the core plate 2 is stacked. A plywood layer sandwiching the sheet heating element 4 is made. Similarly, when manufacturing the 5-ply plywood shown in FIG. Prepare a stack of 4 sheets, such as 1 sheet,
On the other hand, the core board 2 is coated with urea resin adhesive 3 on both sides using a spreader, and the core board 2 is stacked on the previous original board 1, and one original board 1 is placed on top of that. Two original plates 1 with a sheet heating element 4 sandwiched therebetween are stacked to form a plywood layer sandwiching a sheet heating element 4 therebetween.

The above-mentioned planar heating element 4 is made of fluororesin, has flexibility, can generate heat up to about 150°C to 200°C, and is approximately the same size as the original plate 1 and the core plate 2. This allows the entire surface of the plywood to be heated evenly. Further, a terminal 5 is provided at the end of the sheet heating element 4, and a power supply connector 7 can be connected to this terminal 5.

Thus, the original board 1, the core board 2 coated with adhesive 3, and the planar heating element 4 are stacked alternately to form plywood A, and the plywood is laminated to a height of about 1 m with the planar heating element 4 in between. Make layers. Incidentally, at this time, the planar heating element 4 is sandwiched in the above assembly process so that the terminal 5 connected to the power source protrudes in a predetermined direction. The plywood layers laminated in this way are transported to the press device 6 shown in FIG. 3 by appropriate transport means, inserted and placed on the press table 8, and the power supply connector 7 is connected to the terminal 5 of each sheet heating element 4. . And about 10Kg/cm ² with press device 6
While pressing the plywood layer with a pressing force of
Electricity is applied to generate heat at approximately 100℃ to 120℃, and it takes approximately 60 minutes for a 60mm thick plywood and approximately 15 minutes for a 20mm thick plywood.
The urea resin adhesive 3 is heated and cured through the original plate 1 on the front and back sides of each plywood board by generating heat for 10 minutes. When the adhesion is completed, the terminal 5 is removed from the connector 7, the pressure applied by the press device 6 is released, and the plywood layer is taken out from the press device 6, and the plywood layer is transported to the next finishing step with the sheet heating element 4 sandwiched therebetween. In the finishing process, the plywood is cut and surface finished, but when inserting the plywood in the cutting process, as shown in Figure 4, the sheet heating element 4
The formed plywood A' is separated from the formed plywood A', and the formed plywood A' is inserted into a cutting process, and the planar heating element 4 is recovered and reused in the first assembly process.

5 and 6 show an example of forming curved plywood. The upper and lower molds of the press device 6 are arc-shaped convex molds 9a and concave molds 9b, and between these upper and lower molds, as shown in FIG. Then, insert and place the plywood layer sandwiching the sheet heating element 4 shown in FIG. 2, and connect the power supply connector 7 to the terminal 5 of the sheet heating element 4 in the same manner as above.
The plywood A is compressed with a press device 6 to form a curved shape together with the sheet heating element 4, and the sheet heating element 4 is energized to generate heat.
The urea resin adhesive is heated and cured through the front and back original plates 1, and the original plate 1 and the core plate 2 are bonded to form the plywood A into a curved shape. After completion of bonding, the plywood layer formed into a curved shape is taken out from the press device 6, and when inserted into the next finishing process, the curved plywood A'' and the sheet heating element 4 are separated.The sheet heating element 4 is flexible. Because of this, even after being compressed into a curved shape, it can be returned to its original flat shape and can be reused.

In the above embodiment, the mold of the press device 6 has a flat surface and an arcuate surface, but the mold is not limited to this.

(Effects of the Invention) As described above, the present invention consists of plywood being formed by overlapping an original board and a core board, and a planar heating element being sandwiched between the plywood sheets at the same time as the plywood is being laminated. The sandwiched plywood layers can be transported and inserted into a press machine while still being laminated, compressed, and heated, and after completion of adhesion, the laminated layers can be taken out and transported to the next process on Saturdays, allowing the use of conventionally inexpensive urea-based resin adhesives. The so-called hot press, which incorporates a heating device into the press machine, can simultaneously perform the cold press process for temporary gluing, which was used when manufacturing plywood, and the hot press process, which hardens and fixes the adhesive and completely bonds the plywood. The manufacturing process using equipment can be omitted, and the plywood manufacturing process is simplified. In addition, this eliminates the need for inserting and removing plywood between the hot platens of the hot press machine, thereby significantly improving work efficiency.

Furthermore, the plywood is constructed by alternately stacking the original board and the core board coated with adhesive, and is pressed and heated in that state, so there is no chance of the plywood peeling off or shifting during the work.

Furthermore, the sheet heating element generates heat evenly over the entire surface, and the temperature can be easily adjusted to generate heat at a predetermined temperature. The thermosetting adhesive between the core plate and the core plate can be evenly heated and efficiently and reliably cured and bonded.

In addition, when manufacturing the curved plywood shown in the example, since the thickness of the sheet heating element is extremely thin and flexible, it is only necessary to use curved sheets for the upper and lower molds of the press machine. Plywood laminated according to this mold and a sheet heating element are pressed and heated in a curved manner, and the heat generated by the sheet heating element hardens the adhesive and heat-forms the plywood, making it easy to manufacture curved plywood. There are many effects that can be done.

[Brief explanation of drawings]

Figure 1 is a front view showing an example of a combination of a base plate, a core plate, and a planar heating element when manufacturing 3-ply plywood, and Figure 2 shows an example of the combination when manufacturing 5-ply plywood. A front view showing an example, FIG. 3 is a front view of a state in which a plywood layer is press-formed with a press device, and FIG. 4 is a front view showing a state in which the bonded plywood and the sheet heating element are separated after being taken out from the press device.
Fig. 5 is a front view of a state in which a plywood layer is press-formed using a curved press machine, Fig. 6 is a front view showing a state in which the curved plywood and the sheet heating element that have been taken out of the press machine and bonded are separated; FIG. 7 is a front view showing a conventional hot press device. DESCRIPTION OF SYMBOLS 1... Original board, 2... Core board, 3... Thermosetting adhesive, 4... Planar heating element, 5... Terminal, 6... Pressing device, A... Plywood.

Claims (1)

[Claims] 1 Original board 1 and core board 2 coated with thermosetting adhesive 3
Plywood A is constructed by stacking a predetermined number of sheets alternately.
When the plywood A is laminated, the plywood A is laminated with a sheet heating element 4 having flexibility and a terminal 5 for connecting a power source sandwiched between the plywood A and the plywood A. The plywood layers sandwiching the heating elements 4 are transported and inserted as they are into a press device 6, and are pressed by the press device 6. At the same time, a power source is connected to each sheet heating element 4 sandwiched between the plywood layers, and the sheet heating elements 4 are pressed together. A plywood manufacturing method characterized by bonding an original board 1 and a core board 2 by generating heat.