JPS63183819A - Method for molding skin material - Google Patents

Abstract

PURPOSE:To reduce the energy loss and prevent cracks from being produced in the molding surface of a mold by a method wherein thermoplastic powder is adhered electrostatically onto the molding surface of the mold for molding a skin material and, after that, melted by being irradiated with infrared rays with specified wavelength so as to mold the skin material, which is removed from the mold after cooling. CONSTITUTION:A powder container 20, to which a minus pole 103 is connected, and a mold 10, to which a plus pole 102 is connected, are arranged. By driving a motor 16, an arm 12 is rocked to a position (d) and at the same time the molding surface 11 of the mold 10 is faced downwards so as to cover the power container 20. As a result, powder P electrostatically adheres to the molding surface 11. Next, the arm 12 is rocked to a position (e) so as to shift the mold 10 into a melting oven 30 and also to shift the powder container 20 below the mold. After that, a shutter 33 is lowered and far infrared rays with the wavelength nearly the same as the molecule of the powder P (or with the wavelength of about 0.75-1000mum) are irradiated to the mold from an infrared heater 32 and simultaneously the mold is rotated. After that, the mold 10 is shifted to the position (d) so as to be cooled with cooling water jetted from shower nozzles 35 under the state that the molding surface 11 is faced downward and finally the molding is removed.

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 members forming the surfaces of seats, dash panels, etc.

(Prior art) As a conventional method for forming a skin material, for example, the method shown in Fig. 4 (
The methods shown in a) to (C) are used.

In this method, first, as shown in (&), a mold 02 for a skin material 01 is heated with a heater OH to a temperature higher than the melting temperature of the raw material thermoplastic resin OP.

Heat is stored in the mold 02.

Next, as shown in (b), this mold 02 is placed over the container 03 containing the powdered resin OP, and while the mold 02 and container 03 are turned upside down,
It is rotated ao' to adhere the powdered resin OP to the mold surface of the mold 02 and melted at the same time, and then rotated 180 degrees again to return to its original state.

Then, as shown in (e), the back surface of the mold 02 is cooled by pouring cooling water from the nozzle 04, and the molded skin
Demould 1.

The epidermis O1 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 OH as described above, a number of pipes for circulating oil are provided outside the mold 02, and a high temperature is placed inside the pipes during heating. 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.

(2) Conventional methods basically try to melt the resin using heat, and the heat for this melting uses heat stored in the mold.

Therefore, even if heat is released after heating, the mold must store enough heat to melt the resin, which requires more thermal energy than is necessary to melt the resin. , it is uneconomical, and in addition, it takes a lot of time to provide that much energy.
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 can be stored, so the temperature difference between the temperature when it is cooled is large and cracks can occur due to thermal shock. This tends to shorten the life of the mold.

■ Since the resin is melted by the thermal energy of the mold, the temperature of the mold is higher than the temperature of the resin. Therefore, the resin (skin material) must first be cooled until the temperature of the mold reaches the same temperature as the resin. This is done only after it has cooled down. Therefore, the cooling of the mold before the resin begins to cool is
It is a waste of energy and time, and is inefficient.

■ When applying resin, if the temperature of the mold is uneven due to the shape of the mold or heating method, the resin will not be applied evenly 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 adheres to the mold surface of the skin material by static electricity, and then the powder adhered to the mold surface is
The method is characterized in that the skin material is molded by irradiating and melting infrared rays with a wavelength of 0.75 to 1000 pm, and then the skin material is removed from the mold by cooling.

(Function) In the skin material molding method of the present invention, since the method described above is used, 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 infrared irradiation and heat is transferred from the powder (molten resin) side as the temperature rises when the powder is melted, it is not possible to process the powder as in the past. It is not directly heated to a temperature that allows it to adhere and melt, and therefore the mold can be prevented from reaching a high temperature unlike in the past.

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 extremely difficult to heat compared to powder), so that the temperature of the mold can be adjusted to the temperature of the molded skin material. It can be lower than the temperature.

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

(Example) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In describing this embodiment, a case will be taken as an example in which a skin material for an automobile instrument panel is molded.

First, the configuration of a molding apparatus A that employs the molding method of the present invention will be explained.

As shown in FIG. 1, the molding apparatus A of the embodiment includes a mold l.
O1 powder container 20. The main component is a melting furnace 30.

The mold lO 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. Note that this mold lO may be formed by other means than electroforming, such as carving, casting, pressing, etc.

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

The swinging of this 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 achieved by the drive of a motor 16 via a chain 15. It is configured.

The powder container 20 is a container for storing resin powder P, which is a raw material for the skin material S, and this powder container 20 has the following characteristics:
It is formed to be able to charge the powder P in the container, and furthermore, as shown in FIG.
The powder container 20 is supported by a support cart 21 that is slidable in the left-right direction in FIG. It is formed like this.

Therefore, as shown in FIG.
0, and then connect a high voltage electrode 102 to the mold lO to positively charge the mold lO, and connect a negative electrode 103 to the powder container 20 to charge the powder inside. When the powder P is negatively charged, the powder P is uniformly adhered to the mold surface 11 disposed facing the powder P due to static electricity.

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

Further, numeral 22 in FIG. 1 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. The melting furnace 30 is formed into a box shape large enough to accommodate the mold 10, and a notch 37 is provided on the side surface of the melting furnace 30 to avoid interference with the support shaft 13 when the mold 10 is stored. Furthermore, a large number of infrared heaters 32 are provided on the wall surface on the back side of the melting furnace 30.

In particular, this infrared heater 32 is provided with far infrared rays (wavelength 50
A device that emits light with a long wavelength of about 10,004 m is used.

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 on the side thereof, the supporting shaft 10 is attached with the forming mold 10 disposed at the position e.
A notch 34 is formed to prevent interference with the shower nozzle 3 which spouts cooling water W at the front part.
A cooling water pipe 36 in which pipes 5 are connected is provided.

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.

Further, a positive electrode 102 is connected to the mold 10, and a negative electrode 103 is connected to the powder container 20, so that the mold 1O 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. In addition, during this attachment, the mold l
O 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 1G is moved into the melting furnace 30. On the other hand, powder container 2
0 also operates the traverse cylinder 22 to move the support truck 21
It is also moved below the melting furnace 30.

Then, the shutter 33 is lowered to close the opening 31, the infrared heater 32 emits far infrared rays of a predetermined wavelength for a predetermined period of time, and at the same time, the motor 16 is driven and the melting furnace 30 is
The mold lO is rotated within the mold.

Then, the powder P irradiated with far-infrared rays causes a violent resonance phenomenon because the vibration wavelengths are almost the same.

melt. In this way, the powder P is melted and the skin material S is formed.

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

In this way, it can be seen that the temperature rise of vinyl chloride is much faster than that of mold 10, and under the same energy conditions, melting is achieved in a much shorter time than conventional heating of mold lO. .

Further, the temperature of the mold 10 when the powder P is melted with the powder P attached to the mold 10 is approximately the temperature of M when RM reaches the melting temperature T, and the temperature of the mold 10 is around the temperature of M when RM reaches the melting temperature T. It is about 1/2 of the powder P (skin material S).

(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, turn the motor 1 so that the mold surface ll faces down.
6, the mold 10 is rotated.

Next, cooling water is jetted from the shower nozzle 35 to cool the mold 10 and the skin material S, and the skin material S is transferred to the mold 10.
Remove from the mold.

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

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

(2) Since the mold lO is not heated to a high temperature as in the conventional case, the thermal seal is softened and cracks are less likely to occur, extending the life of the mold lO.

(2) Since the powder P is directly melted, 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. Furthermore, since the material is cooled down to the temperature of the skin material S, no energy is wasted, resulting in energy savings.

(2) 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 anything, such as for seats, etc., or for things other than automobiles. It's okay.

Further, in the examples, vinyl chloride is shown as the thermoplastic resin, but as long as it is a thermoplastic resin, materials such as urethane may be used.

In addition, in the examples, infrared rays with long wavelengths (so-called far infrared rays) were used, but this infrared rays are appropriately determined according to the vibration wavelength of the molecules of the resin powder, and have a wavelength of 0.75 to 11,000 IL. 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 molds flow along the process may also be used.

(Effects of the Invention) As explained above, in the method for 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 by indirect heat transfer through a mold,
Energy loss can be reduced and energy savings can be achieved, and the heating time can also be shortened compared to heating a mold with the same energy, resulting in the effect that the molding cycle can be shortened.

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

Furthermore, for the reasons mentioned above, when molding the skin material, the temperature of the mold can be lower than the temperature of the skin material, so as in the past, after molding one skin material, the temperature of the mold is lowered to the temperature of the skin. The cooling time can be shortened without the need for additional steps, 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 attached without causing unevenness, which makes it possible to equalize the thickness of the skin material and improve quality. 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. 3 is a side view showing an example apparatus, FIG. 3 is a graph showing temperature changes of powder and mold based on the method of the present invention, and FIG. 4 is an explanatory diagram showing a conventional example. lO...Mold 11...Mold surface 32...Infrared heater P...Powder S...Skin material 10...Mold 11...Mold surface 32...Infrared heater P. ... Powder S ... Skin material Figure 4 (C)

Claims (1)

[Scope of 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 100.
A method for forming a skin material, characterized in that the skin material is formed by irradiating and melting infrared rays of 0 μm, and then the skin material is removed from the mold by cooling.