JPH0351574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides wood having severe unevenness,
The present invention relates to a method and apparatus for closely adhering a moldable sheet such as a surface protection film, a painted film, or a transfer film to the surface of a molded product made of ceramics, synthetic resin, or the like.

Conventionally, in order to bring a moldable sheet into close contact with a three-dimensional molded product, as shown in FIG.
Lay the moldable sheet 3 on top of this, and
It has been common practice to soften the material by heating and to suction it through the vacuum suction hole 21 to mold it in close contact.

However, if the three-dimensional molded product 1 has a recess on its surface, residual air that cannot be removed by vacuum suction will accumulate in the recess, and the moldable sheet 3 will not adhere to the recess, as shown in FIG. 1B.

A method and apparatus for closely molding a sheet with good formability up to the recesses on a molded article 1 having recesses on its surface is described in Japanese Patent Publication No. 17335/1983.
What is shown in Figure 2 A and B of the drawing is
The present inventors further improved the method and apparatus described in No. 17335. In other words, Figure 2 A,
The apparatus in B has an opening facing downward, is equipped with a heating device 6 inside, and has an upper mold 4 that can be moved up and down by a piston and a cylinder 7, and an upward opening of the same shape as the upper mold 4. and a lower mold 5 that can form a closed space (upper tank A and lower tank B) with the upper mold by sandwiching the formable sheet 3, installed inside the lower mold 5 or at its upper end. Vacuum suction holes 21, 21 inside the product table 2, the upper mold 4 and the lower mold
It consists of a vacuum suction mechanism connected to the upper mold 4, and an air supply device (atmosphere release device) connected to the inside of the upper mold 4.

Therefore, as shown in FIG. 2A, first, the molded product 1 is placed on the product stand 2, the moldable sheet 3 is placed on the lower mold 5, and the upper mold 4 is closed. ,
Closed space (upper tank) A with upper mold 4 and formable sheet 3
Then, a closed space (lower tank) B is created using the lower mold 5 and the moldable sheet 3 (Fig. 2A). Thereafter, the air in the upper tank A and the lower tank B is vacuumed by the vacuum pump 8 through the vacuum suction holes 21 and 21, and the moldable sheet 3 is heated and softened by the heating device 6. Next, the upper tank A is opened to the atmosphere by opening the valve 11, or compressed air is supplied, and the moldable sheet 3 is molded in close contact with the molded product 1 by this air pressure (FIG. 2B).

According to this method, since no air remains in the recesses on the surface of the molded product 1, the moldable sheet 3 comes into close contact with the recesses. However, there is a limit to this contact molding method. Good adhesion can be achieved if the recess has a gentle angle, but as shown in Figure 3A or Figure 4A, there are For molded products that have a deep recess (Fig. 3 (a)) or a deep recess (Fig. 4 (a)), the molded product will not adhere to the recess sufficiently and will end up as shown in Fig. 3 (b) and Fig. 4 (b). .

Until now, the inventors believed that the cause of this was residual air. Even when vacuum is drawn from the vacuum suction hole 21, a complete vacuum is not created, and some residual air remains, which makes it difficult to achieve complete contact. Therefore, it was thought that if the degree of pressure reduction was improved, even if perfect adhesion was not possible, it would be possible to achieve closer to perfect adhesion.

As described above, the degree of pressure reduction is related to the close contact with the recessed portion, but after further investigation, it was found that the degree of pressure reduction and the length of the white part do not necessarily correspond.

Therefore, the inventors of the present invention have begun to consider the possibility that there is another reason for the occurrence of white areas.

As a result, we found the following. That is, the formable sheet 3 is initially heated and softened by the heating device 6, but the supplied air is not heated, and on the contrary, when it is introduced into the upper tank in a vacuum state, it is cooled under reduced pressure. ing. Therefore,
Cooling of the moldable sheet 3 begins simultaneously with the supply of air, and the moldable sheet 3 is further cooled as it comes into contact with point a on the surface of the molded product 1 shown in FIGS. 3 and 4. Therefore, as the formable sheet 3 is stretch-molded from point a to point b, its temperature also decreases, and if this recess is deep (if the length between a and b is long), the sheet may be cooled while it is not in sufficient contact. , it will no longer be molded.

Therefore, in order to prevent this white spot, it is necessary to maintain a sufficient degree of pressure reduction and to maintain the formable sheet 3 in a sufficiently heated state. In order to keep this formable sheet 3 in a sufficiently heated state, a method of heating the supplied air was devised.

The present invention has been made based on the above process. That is, as shown in FIGS. 5 and 6, the apparatus of the present invention has an upper mold 4 having an opening facing downward and having a heating device 6 inside, and an upper mold 4 having the same shape as the upper mold 4. The lower mold 5, which has an upward opening and can form a sealed space with the upper mold 4 by sandwiching a moldable sheet, is moved up and down by moving either the upper mold 4 or the lower mold 5. Opening and closing device that opens and closes the mold,
Consisting of a product stand 2 installed inside the lower mold 5 or at its upper end, a vacuum suction mechanism connected to the inside of the upper mold 4 and the inside of the lower mold, and a heated compressed air supply device connected to the inside of the upper mold 4. This is an adhesion forming device characterized by the following.

The present invention will now be described with reference to FIG. 5 of the drawings.

An upper mold 4 and a lower mold 5 are installed to form an upper tank A and a lower tank B via a moldable sheet 3 such as a flexible film or sheet.

A piston and a cylinder 71 are installed in the upper mold 4 as an opening/closing device for moving the mold up and down to open the upper tank A and the lower tank B, and the upper wall of the upper mold 4 has moldability. A heater 6 is provided to heat and soften the sheet 3. Here, as the formable sheet 3, a flexible film, sheet, thermoflexible film, etc. can be used, such as vinyl chloride, polystyrene, acrylonitrile-butadiene-styrene copolymer (hereinafter abbreviated as "ABS"). ), polypropylene, polyethylene, polyamide, ionomer resin, fluororesin, etc., or a laminated sheet thereof can be used.

In addition, when the purpose is to decorate the molded product 1, as a moldable sheet, as shown in FIG. Adhesive 3 on the surface to be glued with 1
You can also use laminating sheets with 3 applied.
Furthermore, as shown in FIG. 8, a transfer sheet in which a release varnish layer 34, an ink layer 35, and a heat-sensitive adhesive layer 36 are sequentially formed on the surface of a base sheet 31 can also be used.

Further, as the piston and cylinder 71 for vertically moving the upper mold 4, hydraulic or pneumatic pistons can be used. However, when molding a moldable sheet 3 with a large area, the cylinder for closing the upper mold 4 requires a very large force, so a method or a toggle mechanism as shown in Japanese Patent Application No. 16790/1986 is adopted. is advantageous. As the heater 6, an infrared heater, a far-infrared heater, etc. can be used.

Inside the lower mold 5, a breathable product stand 2 and the molded product 1 are installed on it, and the upper and lower molds 4, 5
After closing the upper and lower tanks A and B using the vacuum pump 8,
Further deaerate the air and bring the upper and lower tanks A and B into a reduced pressure state. At the same time, the moldable sheet 3 is heated and softened by the heater 6. Note that the product table 2 may be fixed at a fixed location, but it may also be made vertically movable by means of a piston and cylinder 72, as shown in FIG.

Molded products 1 include wood, plastic molded products,
Although a thermosetting resin molded product, a ceramic molded product, etc. can be used, the present invention is particularly effective when the surface thereof has a recess with a sharp angle or a deep recess.

Vacuum pump 8 for evacuating upper and lower tanks A and B
is connected to a large-capacity pressure-resistant container (accumulator tank) 9 as shown in the figure, and the air from upper and lower tanks A and B is introduced into the accumulator tank 9, which has been evacuated in advance, to quickly fill the upper and lower tanks A. , B are brought into a reduced pressure state, the valves 81 and 82 are electrically switched, and the valve 81 connects the vacuum pumps 8 of the upper and lower tanks A and B, and the valve 82 is closed to connect the vacuum pump 8 and the accumulator tank. By cutting off the connection of 9, the pressure can be quickly reduced. Also, upper and lower tanks A,
After B becomes a vacuum state, the valve 81 is completely closed and the valve 82 is opened to keep the accumulator tank 9 in a reduced pressure state. Here, it is desirable that the accumulator tank 9 has the same volume as the upper and lower tanks or more. After the upper and lower tanks A and B are sufficiently vacuumed and the formable sheet 3 is cured by heating, the valve 83 is closed and the product table 2 is moved upward as necessary, or the product table 2 is moved upwardly, or the valve 84 is opened and closed without moving. Then heated compressed air is introduced into the upper tank. The temperature of the compressed air is cooled under reduced pressure when it is introduced into the tank, so after passing through the heater 61, it is set to a slightly higher temperature, and when it is introduced into the upper tank A, the temperature is between 30°C and 200°C. It is desirable to set it. The compressor 1 heats this compressed air.
This is possible by installing a heater 61 between the upper tank A and the upper tank A, and the temperature can also be controlled thereby. To explain the temperature of the heated air and its effects more specifically, the higher the temperature of the heated air, the better the formability of the formable sheet 3, but if the temperature is higher than or close to the flow temperature of the formable sheet 3, it may cause problems during forming. Wrinkles are likely to occur in the formable sheet 3. Therefore, the temperature of the heated air is desirably higher than the softening point of the formable sheet 3 and lower than the flow start temperature, more preferably 10° C. or more lower than the flow start temperature.

Further, the pressure of the heated air is preferably atmospheric pressure or a pressure higher than atmospheric pressure, and a pressure of about 2 kg/cm ² is sufficient.

After molding the moldable sheet 3 in close contact with the molded product 1 in this way, air vent holes (omitted in the drawing to avoid complication of the drawing) are opened, and the upper and lower tanks A,
B is returned to atmospheric pressure, the upper mold 4 is opened, and the molded product 1 covered with the moldable sheet 3 is taken out. If the moldable sheet 3 is a laminating sheet shown in FIG. 7, the sheet-covered molded product is produced by cutting off unnecessary parts of the sheet at the ends of the molded product, finishing the sheet, and then forming the sheet 3.
If the structure is for transfer use, a molded product with a transfer pattern can be obtained by peeling the sheet 3 from the molded product.

FIG. 6 shows yet another contact molding device. The heated air supply device is compressor 10.
and an accumulator tank 11 having a heater 62, which is otherwise the same as that shown in FIG. In FIG. 6, the compressed air sent from the compressor 10 is transferred to the accumulator tank 11.
The air in the tank 11 is heated to a predetermined pressure using a pressure gauge, a pressure regulating valve, and a thermometer (not shown). Adjust to temperature. For example, if the volume of the upper tank A after air introduction is 30, the accumulator tank 11 should be 30, the pressure should be about three times the final pressure in the upper tank A, and the temperature should be slightly higher than the final introduction temperature. Just set it. When using this device, the valve 86 is closed, the valve 85 is opened, compressed air is introduced from the compressor 10, and when the predetermined pressure is reached, the valve 85 is opened.
Close 5. Thereafter, the air is heated by the heater 62 and adjusted to a predetermined pressure and temperature. If the pressure rises before the temperature rises sufficiently, all you need to do is release the pressure using the pressure control valve. When the pressure and temperature of the air are as set, the valve 86 is opened and the air is introduced into the upper tank from the upper mold to form the moldable sheet 3, and the molded product 1 and the sheet 3 are brought into close contact to obtain the desired molded product. .

The following will be explained based on examples.

Example 1 A wood grain print was applied to a semi-rigid vinyl chloride sheet (200μ), and an adhesive was applied to the opposite side by gravure printing. The sheet was sandwiched between an upper mold 4 and a lower mold 5 with the adhesive side facing an ABS molded product having a cross section as shown in FIG. 9, and the upper and lower molds were sealed. Thereafter, as shown in Fig. 5, the valve 82 is closed, the air in the upper and lower chambers is drawn into the large-capacity pressure-resistant container 9 that has been evacuated in advance, and the valve 81 is operated when the pressures in the tank 9 and the upper and lower chambers are almost balanced. Then, the tank was evacuated using a vacuum pump, and the tank 9 was sealed. When the vacuum level of the upper and lower tanks reaches 10 ^-1 Torr,
The valves 81 and 82 are closed to make the upper and lower tanks a closed system, and the air sent from the compressor 10 passes through the heater 61. The temperature is adjusted to 105°C, and the valve 83 is operated to introduce hot air into the upper tank. The pressure was set at 2 Kg/cm ² . Exhaust from the exhaust port after about 2 seconds,
After supplying air and returning the upper and lower tanks to atmospheric pressure, the upper mold 4 was raised and the closely molded product was taken out. The close contact molded product was molded to the grooves shown in c and d in FIG. 9, and the molded product and the sheet were in sufficient contact.

Example 2 A transfer sheet was prepared by sequentially printing a rubber release varnish, an ink pattern layer (wood grain), and an acrylic resin adhesive on a semi-rigid vinyl chloride sheet (thickness: 100 μm) using a gravure method.

An ABS molded product having a cross section as shown in Fig. 10 is placed on the product table in the lower mold, and the transfer sheet is sandwiched between the upper and lower molds with the printed side facing the ABS molded product.
After sealing, sheet molding was performed in the same manner as shown in Example 1 to obtain a close-contact molded product. When the resulting molded product is taken out and the PVC sheet is peeled off from the ABS molded product, the wood grain print pattern is transferred onto the ABS molded product.
In the figure, only the printed pattern was transferred to the open area e of the window, and the wood grain was beautifully applied even to the deepest part of the V-groove f.

[Brief explanation of drawings]

Figure 1 A and B, Figure 2 A and B are explanatory sectional views explaining the conventional device and its usage method, and Figure 3 A and
4A and 4B are perspective views and sectional views showing a molded product formed by contact molding by a conventional method, FIGS. 5 and 6 are explanatory sectional views showing the apparatus of the present invention, and FIGS. 7 and 8. The figures are cross-sectional views of the formable sheet, Figures 9 A and B, and 10.
Figures A and B are a perspective view and a sectional view showing molded products used in Examples. DESCRIPTION OF SYMBOLS 1...Molded product, 2...Product table, 21...Vacuum suction hole, 3...Moldable sheet, 31...Base material sheet, 32...Printing, 33...Adhesive, 34...Peelable varnish layer , 35... Ink layer, 36... Heat sensitive adhesive layer, 4... Upper mold, 5... Lower mold, 6... Heater, 61, 62... Heater, 71, 72...
Piston and cylinder, 8... Vacuum pump, 8
1, 82, 83, 84, 85, 86... valve,
9...Large capacity pressure vessel (accumulator tank), 10...Compressor, 11...Accumulator tank.

Claims (1)

[Claims] 1. An upper mold 4 having an opening facing downward and equipped with a heating device 6 inside, having an opening facing upward in the same shape as the upper mold, and sandwiching a molded sheet. Upper mold 4
A lower mold 5 capable of forming an airtight space with a vacuum suction mechanism connected to the inside of the upper mold 4 and the inside of the lower mold, a heated compressed air supply device connected to the inside of the upper mold 4, and a formable sheet heating device provided inside the upper mold. A contact molding device characterized by comprising: 2. Place the molded product on the product stand 2 installed inside or at the upper end of the lower mold, place the moldable sheet on the lower mold, close the upper and lower molds, and sandwich the moldable sheet. A sealed space is formed by the upper mold and the lower mold, and then a space A consisting of the upper mold and the formable sheet and a space B consisting of the lower mold and the formable sheet are separated by a vacuum suction mechanism. Along with vacuum suction,
The moldable sheet is heated and softened by a heating device installed inside the upper mold, and then heated compressed air is supplied to the space A composed of the upper mold and the moldable sheet, thereby converting the moldable sheet into a molded product. A contact molding method characterized by molding in close contact with the surface.