JPH0481924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for molding a skin material molded from resin and used for a member forming the surface of a sheet, a dash panel, or the like.

(Prior Art) Conventionally, as a method for forming a skin material, methods such as those shown in a to c in FIG. 4 have been used, for example.

In this method, first, as shown in a, the mold 02 of the skin material 01 is heated with a heater 0H to a temperature higher than the melting temperature of the raw material thermoplastic resin 0P.
to heat up.

Next, as shown in b, this mold 02 is placed over the container 03 containing the powdered resin 0P, and the mold 02 and the container 03 are rotated 180° upside down while still in this state. The powdered resin 0P is adhered to the mold surface of the mold 02 and melted at the same time, and the mold is rotated 180° again to return it to its original shape.

Then, as shown in c, the back surface of the mold 02 is cooled by spraying cooling water from the nozzle 04, and the molded skin material 01 is removed from the mold.

The skin 01 is formed as described above.

In addition to the method of heating and cooling the mold 02, in addition to the method using the heater 0H as described above, a number of pipes are installed outside the mold 02 to circulate oil, and inside these pipes there is a high temperature There is also a method of circulating oil, and also circulating low-temperature oil during cooling.

(Problems to be Solved by the Invention) However, such conventional methods of forming skin materials have the following problems.

The conventional method basically attempts to melt the resin using heat, and the heat stored in the mold is used as the heat for this melting.

Therefore, even if heat is released after heating, the mold must store enough heat to melt the resin. In addition, it requires a lot of time to provide that much energy, and it is uneconomical.
A large-capacity heating device may be required.

The mold is repeatedly heated and cooled, but as mentioned above, the mold is heated to a high temperature so that a sufficient amount of heat is stored, so the temperature difference between the temperature when it is cooled and the temperature during cooling is large, causing cracks due to thermal shock and molding. The life of the mold tends to be shortened.

Because the resin is melted by the heat energy of the mold,
The temperature of the mold is higher than the temperature of the resin, so the resin (skin material) must be cooled only after the mold has been cooled to the same temperature as the resin. Therefore, cooling the mold before the resin begins to cool is wasteful in terms of energy and time, and is inefficient.

When applying resin, if there are temperature irregularities in the mold due to the shape of the mold or heating method, the resin will not be evenly applied and the thickness of the molded skin material will not be uniform.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above-mentioned problems, and in order to achieve this purpose, the present invention uses thermoplastic resin powder. , the powder is attached to the mold surface of the skin material mold by static electricity, and then the powder adhered to the mold surface is heated with a wavelength of 0.75 to 1000μ.
The method is characterized in that the skin material is molded by irradiating and melting infrared rays of m, and is then cooled and removed from the mold.

(Function) Since the skin material molding method of the present invention employs the above-described means, the thermoplastic resin powder, which is the raw material for the skin material, is adhered to the mold surface of the mold by static electricity. Further, the powder is melted by the powder resonating in response to infrared rays having the same wavelength as the vibration wavelength of the powder (polymer material).

Therefore, although the mold is heated by the powder (molten resin) side as the temperature rises when the powder melts, and is heated by infrared irradiation, The mold is not directly heated to a temperature at which it can be attached and melted, and therefore the mold can be prevented from reaching a high temperature as in the conventional case.

In addition, for the reasons mentioned above (to explain further, molds have strong molecular bonds and are difficult to resonate with infrared rays, so they are much harder to heat than powders).
The temperature of the mold can be lower than the temperature of the molded skin material.

Therefore, from the moment the skin material is molded, heat is taken away by the mold and the skin material is cooled.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.
In describing this embodiment, a case of molding a skin material for an automobile instrument panel will be taken as an example.

First, a molding apparatus A adopting the molding method of the present invention
The configuration of is explained.

The molding apparatus A of the embodiment, as shown in FIG.
The main components are a mold 10, a powder container 20, and a melting furnace 30.

The mold 10 is a mold formed by electroforming of nickel or copper, and as shown in FIG. 1, a mold surface 11 of a skin material S is formed on the inner surface. still,
The mold 10 may be formed by other means than electroforming, such as carving, casting, and pressing.

Further, as shown in FIGS. 1 and 2, this mold 10 has an arm 12 relative to the device base 101.
It is swingably supported from position d to position e in the figure, and is rotatably supported with respect to arm 12 by a support shaft 13 provided at the tip of arm 12.

The swinging of the arm 12 is achieved by the expansion and contraction of an air cylinder 14 connected to the lower end of the arm 12, and the rotation of the mold 10 is caused by the chain 15.
This is accomplished by driving the motor 16 via the motor 16.

The powder container 20 is a container for storing resin powder P which is a raw material for the skin material S, and is formed to be able to charge the powder P in the container. , as shown in FIG. 2, in the front-rear direction (left-right direction in FIG. 2) with respect to the device base 101.
The powder container 20 is supported by a support cart 21 that is slidably provided, and the upper end edge of the powder container 20 is formed to substantially match the shape of the edge of the mold surface 11 of the mold 10.

Therefore, as shown in FIG. 2, the mold 10 is placed so as to cover the powder container 20, and the high voltage electrode 102 is connected to the mold 10.
When the powder container 20 is charged positively and the powder P inside is charged negatively by connecting the negative electrode 103 to the powder container 20, the powder P is electrostatically charged to the mold surface placed facing the powder P. 11 evenly.

The powder P is made of thermoplastic resin such as vinyl chloride, and in this embodiment, vinyl chloride is used.

Further, numeral 22 in the figure indicates a traverse cylinder for sliding the support cart 21.

The melting furnace 30 is for melting the powder P, and is supported by the device base 101 and has an opening 31 only on the front side. Molding mold 10
It is formed into a box shape large enough to store the
A notch 37 is formed on the side surface of the melting furnace 30 to avoid interference with the support shaft 13 when the mold 10 is stored, and an infrared heater 32 is formed on the back wall of the melting furnace 30. There are many.

This infrared heater 32 is particularly one that emits far infrared rays (long wavelengths of about 50 to 1000 .mu.m) having substantially the same wavelength as the vibration wavelength of the molecules of the powder P (vinyl chloride).

Further, the melting furnace 30 is provided with a shutter 33 that opens and closes the opening 31. This shutter 33 is provided so as to be able to slide up and down with respect to the melting furnace 30, and the mold 10 is placed at the position e on the side.
A notch 34 is formed to prevent interference with the support shaft 13 in the state in which the cooling water pipe 36 is connected to a shower nozzle 35 for spouting cooling water w. It is being

Next, the operation of the embodiment will be explained based on the method of the present invention.

(a) Powder adhesion process First, the powder P is applied to the entire mold surface 11. In this case, the powder container 20 is placed in advance at a position corresponding to position d of the mold 10.

Additionally, a positive electrode 102 is connected to the mold 10, and a negative electrode 102 is connected to the powder container 20.
3, the mold 10 is positively charged, and the powder P is negatively charged.

Then, as shown in FIG. 2, the air cylinder 14 is actuated to swing the arm 12 to the d position, and the motor 16 is driven so that the mold surface 11 of the mold 10 faces downward. cover the powder container 20.

Then, the negatively charged powder P is attached to the positively charged mold surface 11 of the mold 10 by static electricity. Since the adhesion is caused by static electricity, the powder P is evenly adhered to the entire surface. Incidentally, during this attachment, the mold 10 and the powder container 20 may be rotated together.

(b) Molding process After the powder P is attached to the mold surface 11, the air cylinder 14 is operated to swing the arm 12 to position e, and the mold 10 is moved into the melting furnace 30. On the other hand, the powder container 20 is also moved below the melting furnace 30 together with the support cart 21 by operating the traverse cylinder 22 .

Then, lower the shutter 33 and open the opening 31.
is closed, far infrared rays of a predetermined wavelength are emitted from the infrared heater 32 for a predetermined time, and at the same time, the motor 16 is driven to rotate the mold 10 within the melting furnace 30.

Then, the powder P irradiated with far-infrared rays causes a violent resonance phenomenon because the vibration wavelengths are almost the same, and is melted. In this way, the powder P is melted and the skin material S is formed.

Figure 3 shows the relationship between the temperature change of the powder P and time during melting by far infrared rays based on experimental results. In the figure, T indicates the melting temperature of vinyl chloride, and R indicates the temperature of vinyl chloride. The temperature change for a single unit, RM is the powder P when the powder (vinyl chloride) P is attached to the mold 10.
temperature change, M is mold 1 for mold 10 alone
0 temperature change is shown.

As described above, the temperature of vinyl chloride rises much faster than that of the mold 10, and under the same thermal energy conditions, melting can be achieved in a much shorter time than conventional heating of the mold 10. I understand.

Further, the temperature of the mold 10 when the powder P is melted with the powder P attached to the mold 10 is as follows:
The temperature is around the temperature t of M when RM reaches the melting temperature T, and is about 1/2 that of the powder P (skin material S) in a molten state.

(c) Mold removal process As mentioned above, when the molding is completed by emitting infrared rays for a predetermined period of time, the shutter 33 is slid upward to open the opening 31, and the arm 12 is swung to move the mold 10 to the d position. let At the same time, the mold 10 is rotated by the motor 16 so that the mold surface 11 faces downward.

Next, cooling water is injected from the shower nozzle 35 to cool the mold 10 and the skin material S, and the skin material S is removed from the mold 10.

During this cooling, the mold 10 does not reach a higher temperature than the skin material S, so the skin material S begins to be cooled by the mold 10 in contact with it as soon as it is molded. There is no need to cool the material 10 to the temperature of the skin material S.

As explained above, in embodiment A, the following effects can be obtained.

Since the mold 10 is not heated to a high temperature as in the conventional case, the thermal shock is relieved and cracks are less likely to occur, and the life of the mold 10 is extended.

Since the powder P is directly melted, the melting can be performed using less energy and in less time than when heat is transferred through the mold 10, making it possible to save energy and shorten the molding cycle.

Since the temperature of the mold 10 can be lower than that of the skin material S during molding, there is no need to first cool the mold 10 to the temperature of the skin material S during cooling, as in the past, and the cooling time is reduced accordingly. The molding cycle can be shortened. Moreover,
By being cooled to the temperature of the skin material S, no energy is wasted, resulting in energy savings.

Since the powder P is attached to the mold surface 11 using static electricity, the powder P can be attached to the mold surface 11 without unevenness, and the quality of the skin material S is improved.

Although the embodiments of the present invention have been described above in detail with reference to the drawings, the specific configuration is not limited to these embodiments. For example, in the embodiments, the skin material used in an automobile instrument panel is However, if it is a skin material molded from resin, it can be used for other parts such as seats, or for things other than automobiles. It's okay.

Further, in the examples, vinyl chloride is shown as the thermoplastic resin, but other thermoplastic resins such as urethane may be used.

In addition, in the examples, infrared rays with a long wavelength (so-called far infrared rays) were used, but this infrared ray is appropriately determined according to the vibration wavelength of the molecules of the resin powder, and has a wavelength of 0.75 to 1000 μm. Any wavelength of infrared rays may be used.

Further, in the embodiments, an independent molding device embodying the present invention is shown, but a line in which the molds flow along the process may also be used.

(Effects of the Invention) As explained above, in the method of molding a skin material of the present invention, the resin powder attached to the mold is directly melted by resonating with infrared rays. Compared to melting through indirect heat transfer through a mold, energy loss is reduced and energy savings can be achieved, and heating time can also be shortened compared to heating the mold with the same energy. This has the effect of shortening the molding cycle.

In addition, as described above, in the present invention, since the resin powder is directly melted and the mold is basically not heated, the temperature of the mold can be prevented from becoming as high as in the past during heating. Thermal shock caused by repeated heating and cooling is alleviated, making it difficult for cracks to occur, resulting in the effect that the life of the mold can be extended.

Furthermore, for the above-mentioned reasons, when molding the skin material, the temperature of the mold can be lower than the temperature of the skin material. The cooling time can be shortened without the need for a cooling process, and this also has the effect of shortening the molding cycle.

In addition, since the powder is attached to the mold surface using static electricity, it can be applied without unevenness, making it possible to equalize the thickness of the skin material and improve quality. The effect is obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a molding apparatus according to an embodiment of the present invention, FIG. 2 is a side view showing the embodiment apparatus, and FIG. 3 is a graph showing temperature changes of powder and molding die based on the method of the present invention. , FIG. 4 is an explanatory diagram showing a conventional example. 10... Molding mold, 11... Mold surface, 32... Infrared heater, P... Powder, S... Skin material.

Claims (1)

[Claims] 1. Thermoplastic resin powder is attached to the mold surface of a mold for the skin material by static electricity, and then the powder adhered to the mold surface is heated at a wavelength of 0.75 to
A method for forming a skin material, characterized in that the skin material is formed by irradiating and melting infrared rays of 1000 μm, and then the skin material is removed from the mold by cooling.