JP2935800B2 - Compression mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression molding die for obtaining a resin molded product using a glass fiber reinforced thermoplastic resin sheet such as a stampable sheet.

[0002]

2. Description of the Related Art Conventionally, it has been known that compression molding using a stampable sheet is used for molding a frame of an automobile seat, for example. In the compression molding, the stampable sheet is cut in accordance with the male and female molds, the cut stampable sheet is heated and softened and placed in the male and female molds, and compression-molded by the male and female molds. Is typed by

When the above-mentioned conventional compression molding method using a stampable sheet is used for producing a plate-shaped resin molded product in which an electric heating element is sealed, which requires water resistance and electrical insulation, for example, In the compression molding method, a laminate is formed by laminating a stampable sheet, an electric heating element to be sealed, and a stampable sheet in a lower female mold, and then heating the laminate to form the stampable sheet. A method was considered in which the thermoplastic resin of the sheet was brought into a molten state, and then the laminate was pressed to produce a resin molded product.

In such a method, when the thermoplastic resin of the stampable sheet is polypropylene, after laminating the laminate in a lower female mold, an upper male mold is brought close to the laminate, and Then, the upper and lower molds are set at, for example, 220 ° C.
After heating the laminate to melt the thermoplastic resin, the upper and lower molds are cooled to about 100 ° C., and the resin is formed by compression molding by clamping the upper and lower molds. We have obtained molded products.

[0005]

However, in the above-mentioned conventional mold, the obtained plate-shaped resin molded product remains in the lower female mold even when the mold is opened. If a conventional ejector pin is used when taking out, that is, removing the mold, the pin remains on the surface of the resin molded product.

[0006] This causes a problem that it takes time to shape the obtained resin molded product. In addition, when a manual operation using a suction cup or the like is used for the above-described demolding operation, there is a problem that it takes time to demold the obtained resin molded product.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a compression molding die according to the present invention is characterized in that a laminate formed by laminating sheets made of a thermoplastic resin containing fibrous materials is used. In a compression mold for forming a resin molded product by compression molding with a mold and a lower female mold, the lower female mold is moved by placing the fixed lower mold portion and the laminated body. It can be divided into a possible flat receiving plate. On the other hand, in the upper male mold, the above-mentioned laminated body accommodated by the receiving plate in the lower female mold is clamped and formed. And an edge portion for forming a shear edge of the lower female die together with the lower die portion.

Examples of the thermoplastic resin include simple substances and copolymers of polypropylene, polybutylene terephthalate, polyethylene terephthalate, polyphenylene oxide, high-density polyethylene, polyamide, polyphenylene sulfide, polyetherimide, poly (meth) acrylate and the like. Can be.

As the above fibrous material, glass fiber, carbon fiber, inorganic fiber such as whisker, aramid fiber, and boron fiber are used alone or in combination. The fibrous material has a fiber length of 6 mm or more and a fiber thickness of 10 μm or more, and 15 to 50% by weight based on the thermoplastic resin.
Used as a mixture.

[0010]

According to the above construction, the laminated body is placed on a movable receiving plate which can be divided and moved as a part of the lower female mold, and the receiving plate is mounted on the fixed lower mold portion, thereby forming the upper male mold. When the mold is clamped against the lower female mold, a shear edge of the lower female mold is formed by the edge portion of the upper male mold and the lower mold portion. This makes it possible to obtain a resin molded product by compression-molding the laminate by clamping the upper male mold and the lower female mold.

On the other hand, in the above configuration, the resin molded product is
When the upper male mold and the lower female mold are opened, the receiving plate can be moved horizontally from the lower mold part and taken out. Further, since the receiving plate is flat, it can be easily removed from the receiving plate. Can be taken out. Therefore, the above configuration can facilitate the release of the obtained resin molded product.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In the compression molding die, as shown in FIGS. 1 and 2, a laminate 1 in which a sheet-like material made of a thermoplastic resin containing a fibrous material for increasing the strength and an object to be sealed are placed. The movable receiving plate 2 is provided so as to be detachable with respect to the fixed lower mold 3 and to hold the laminate 1 at a predetermined position when mounted on the lower mold 3. ing.

The receiving plate 2 is provided with a mounting portion 2a on which the laminate 1 can be overlapped.
Fixing hole 2c for fixing the fixing member at a predetermined position of the lower mold 3.
Are provided at two locations so that fixing pins (not shown) can be inserted therethrough. Therefore, the lower die 3 is provided with fixing holes 3b into which the fixing pins inserted through the fixing holes 2c are fitted.

Further, the lower mold 3 has a built-in lower heater 3c for heating so as to maintain a predetermined temperature, while the upper male mold 4 has a predetermined temperature. Are built-in.

The lower mold 3 is used to heat the lower mold 3 so as to maintain a predetermined temperature, and the heat from each of the lower heaters 3c is efficiently transmitted to the lower mold 3. The upper male mold 4 is provided with an upper heater 4a for heating to maintain a predetermined temperature, and heat from the upper heaters 4a. An upper heat insulating layer 4c for efficiently transmitting the upper male mold 4 is incorporated.

The upper male mold 4 has an upper male mold 4
When the lower female mold 3e is clamped to the lower female mold 3e,
A rising portion (edge portion) 4b that forms one side of the shear edge 3a of e is erected downward along one side of the upper male mold 4. The above-mentioned shear edge 3a
The term “part” refers to a portion of the lower female mold 3 e where the laminated body 1 is formed by abutting the periphery thereof.

This eliminates the need to form a part of the shear edge 3a, so that the receiving plate 2 can be formed in a flat plate shape. In addition, the starting unit 4b
Forms one side of the shear edge 3a when clamping the mold, but is arranged so as not to hinder the horizontal movement of the receiving plate 2 on which the laminate 1 is placed when the mold is opened. It is possible. Therefore, when the mold is opened, the receiving plate 2 can be moved in the horizontal direction on the lower mold 3 to be detached.

Next, a description will be given of a method for manufacturing a resin molded body using the above-described compression mold and a heating element made of a barium titanate-based ceramic semiconductor having a positive temperature characteristic (PTC) as an object to be sealed. I do.

In the above-mentioned manufacturing method, as shown in FIG. 3, first, a stampable sheet having a thickness of 0.85 mm (C8010-N, manufactured by Cape La Sheet Co., Ltd., composition: 60% by weight of polypropylene resin, 40% by weight of glass fiber) Cut into 15cm squares and 2
The upper sheet 6 and the lower sheet 5 were used.

On the other hand, a stampable sheet having a thickness of 2.5 mm (manufactured by Cape La Sheet Co., Ltd., trade name: C8030-N, composition: polypropylene resin 60 wt%, glass fiber 40 wt%) is cut into 15 cm squares, and A plurality of fixing holes 7 having a diameter of 15 mm were respectively opened at positions symmetrical with respect to the center of the sheet so as to penetrate the front and back surfaces to form a perforated sheet 8.

The heating element 9 as an object to be sealed was formed into a disk having a diameter of 15 mm and a thickness of 2.5 mm. The heating element 9 has electrodes formed by baking silver paste, for example, on the upper and lower surfaces thereof.

A perforated metal plate 10 was used to supply power to the heating element 9 and efficiently radiate heat from the heating element 9 to the outside. The perforated metal plate 10 is an aluminum plate which is 14 cm square and formed to a thickness of 1 mm, and has holes of 5 mm in diameter formed in a grid pattern. Although not shown, a lead wire is soldered to each of the perforated metal plates 10 on one side which is an opposing surface.

Next, the mounting portion 2a of the receiving plate 2 on which a 15 cm square molded product in which a part of the lower female mold 3e is detachably divided is mounted.
On the lower sheet 5, perforated metal plate 10, perforated sheet 8
Are sequentially overlapped, and the fixing holes 7 of the effective sheet 8 are formed.
Heating elements 9 are fitted into the perforated metal plates 1 respectively.
0, the top sheet 6 is laminated in this order to form the laminate 1.

Thereafter, the receiving plate 2 on which the above-mentioned laminate 1 is placed
Is placed on the lower heating plate 11a of the heater having the upper and lower heating plates 11a and 11b, as shown in FIG.
Heat for 7 minutes.

Even when the sheet is heated as described above, the upper sheet 6, the perforated sheet 8, and the lower sheet 5 melt their polypropylene resins, but the glass filled in each of the sheets 5, 6, 8 The polypropylene resin does not flow out by the fibers, and is held on the receiving plate 2 while maintaining the shape of each of the sheets 5, 6, and 8.

At this time, in the above method, since the laminate 1 expands mainly in the layer direction as the temperature increases, the interval h between the upper heating plate 11b of the heater and the laminate 1 is set to a predetermined interval, For example, the upper heating plate 11b is moved upward in accordance with the expansion of the laminated body 1 so as to maintain an interval of 2 mm, for example.

Next, the receiving plate 2 is inserted into the lower mold 3 as shown in FIG. 1, and is inserted into the fixing holes 2c and 3b as shown in FIGS. , And is fixed to the lower mold 3 by inserting the fixing pin 12 therethrough. Thereafter, when the upper male mold 4 is lowered with respect to the lower mold 3 and the mold is clamped, the lower female mold is formed by the rising portion 4b of the upper male mold 4 and the shear edge portion 3a of the lower mold 3. 3e is formed.

The upper male mold 4 and the lower female mold 3e are clamped at a temperature of 100 ° C. under a molding pressure of 1 kg / cm ² for 1 minute, and the laminate 1 is cooled and pressed. 1. A resin molded body 13 in which each of the sheets 5, 6, 8 shown in FIG.
15 cm × 15 in which each perforated metal plate 10 and each heating element 9 sandwiched between each perforated metal plate 10.
A sheet heater of cm × about 5 mm was obtained.

Thereafter, the mold is opened, and the receiving plate 2 on which the planar heater is mounted is taken out from the lower mold 3 in the horizontal direction. Since the receiving plate 2 is flat, the planar heater is connected to the receiving plate 2.
It could be easily removed from, that is, removed from the mold.

In this planar heater, the entire surface of the heating element 9 and the perforated metal plate 10 were covered with a polypropylene resin having glass fibers, and had good electrical insulation with the outside. Therefore, it can be suitably used in a flooded position or in a high humidity atmosphere. The heating element 9 used is a PTC (Positive Temperature Co).
Since it is made of a barium titanate-based porcelain semiconductor having efficient characteristics, it has a self-temperature control function, and the planar heater can simplify temperature control.

As described above, in the compression mold of the above embodiment, since the upper male mold 4 is provided with the rising portion 4b which forms one side of the shear edge 3a of the lower female mold 3e, it is a resin molded product. When the upper male mold 4 and the lower female mold 3e are opened, a sheet heater can move the receiving plate 2 horizontally from the lower mold 3 and take it out. Since the flat heater can be formed, the planar heater can be easily taken out from the receiving plate 2.

By the way, conventionally, since the sheet heater, which is a resin molded product, remains in the lower female mold when the mold is opened, the mold needs to be manually removed by a suction cup or the like, and it takes time to remove the mold. However, in the compression molding die, the manual operation as described above can be omitted, so that the removal of the plate-shaped resin molded product can be facilitated.

Conventionally, a method is also known in which a protruding pin such as an ejector pin is formed on a mold for demolding, and the protruding pin is returned to an original position after demolding. However, in the above configuration, it is not necessary to form such a protruding pin, so that a completely flat appearance without traces of the protruding pin removed on the surface of the planar heater that is the obtained resin molded product is obtained. It is possible to obtain.

By the way, instead of the receiving plate 2, it has been considered to use a receiving plate 15 having an upright plate 14, as shown in FIG. 7, for example. The upright plate 14 corresponds to the rising portion 4b, and the receiving plate 15 is
Is mounted on the lower female mold 3e.
Is formed.

However, after the stack 1 is placed on the receiving plate 15, as described above, the upper and lower heating plates 11a and 1a
1b, when the laminated body 1 is heated for a predetermined time so as to reach a predetermined temperature, the receiving plate 15 is made of a metal which is a good conductor of heat because of the need for heat resistance and durability.
A large amount of heat leaks to the outside via the standing plate 14.

Therefore, when the receiving plate 15 is used, unevenness in the heating temperature occurs in the laminated body 1 to be heated, and the expansion of the laminated body 1 in the layer direction is different, so that the lamination on the standing plate 14 side is different. The expansion of the body 1 is small, and the expansion of the laminate 1 on the opposite side is large.

When the upper heating plate 11b is moved upward in order to maintain the distance h between the upper heating plate 11b and the laminate 1, the laminate 1 on the standing plate 14 side and the upper heating plate 1
Since the interval of 1b is increased and the heating efficiency is reduced, the expansion of the laminate 1 on the standing plate 14 side is further reduced as compared with the expansion on the opposite side.

Accordingly, when the receiving plate 15 is used, it takes time to heat the entire laminate 1 to a predetermined temperature at which the laminate 1 can be compression-molded, and viscosity unevenness due to temperature unevenness on the surface of the laminate 1 is obtained. As a result, the surface condition of the obtained sheet heater may be degraded, for example, wrinkles may occur, and the appearance of the obtained sheet heater may be deteriorated.

However, in the configuration of the above embodiment, since the receiving plate 2 is flat and has no projections, the heating conditions for the placed laminate 1 can be made uniform, and the
Uneven heating can be avoided. As a result, the time required to heat the entire laminate 1 to a predetermined temperature at which compression molding can be performed can be shortened. In addition, the state of the surface of the planar heater caused by the viscosity unevenness due to the temperature unevenness of the surface of the laminate 1 That is, deterioration of the appearance can be prevented.

In order to continuously manufacture the planar heater, it is conceivable to continuously pass a plurality of receiving plates 2 on which the laminated body 1 is placed through a heating furnace. It is advantageous for continuous processing that 2 is a flat plate and does not have a projection.

On the other hand, in the conventional method of manufacturing a resin molded article having an object to be sealed, when the heated laminate is gripped and moved, or placed in a lower mold, the heated laminate has a molten thermoplastic resin. In some cases, the shape of the laminate was distorted, resulting in molding failure.

For this reason, conventionally, a laminate having a sheet made of a thermoplastic resin, for example, a sheet made of polypropylene, is prepared in a lower female mold, and an upper male mold is brought close to the laminate. The upper and lower molds are heated to, for example, about 220 ° C., and the laminate is heated so that the thermoplastic resin is melted. Then, the temperature of the upper and lower molds is cooled to about 100 ° C. A resin molded product has been obtained by compression molding by clamping the mold.

However, in the above-described method, the provision of the receiving plate 2 allows the laminated body 1 placed on the receiving plate 2 to be heated and moved. It can be moved by the receiving plate 2 while maintaining its shape, and can be mounted in the lower mold 3. Thus, the above-described method can save the labor and time for cooling the upper and lower molds that have once been heated to a high temperature as in the related art, so that the planar heater that is a resin molded product obtained from the laminate 1 can be used. Production time can be shortened.

Further, in the method of the above embodiment, the perforated metal plate 10 has holes formed in a grid pattern.
It is not limited to the above, and it is sufficient that the hole has a diameter smaller than the diameter of the heating element 9 and through which a softened propylene resin or the like can pass. For example, a wire netting can be used.

Further, in the method of manufacturing a resin molded product of the above embodiment, an example in which one receiving plate 2 is used has been described, but a plurality of receiving plates 2 may be used. By using the plurality of receiving plates 2, the receiving plate 2 on which the heated laminate 1 is placed is attached to the lower mold 3, and while the laminate 1 is being cooled and pressed, another receiving plate 2 is attached. By mounting and heating a new laminate 1, it is possible to reduce the production cycle time of the resin molded product using the laminate 1.

In the above embodiment, when the receiving plate 2 on which the laminated body 1 is mounted is attached to the lower mold 3, the tip of the rising portion 4b is detachably fitted on the upper surface of the receiving plate 2. A groove (not shown) may be formed. Thereby, the moving distance of the upper male mold 4 can be set large, and a large compression pressure can be obtained, so that a more dense resin molded body can be obtained, and the design flexibility of the resin molded body can be obtained. Can be increased.

[0047]

As described above, the compression mold according to the present invention comprises: a lower female mold for forming a resin molded product by compression molding; It can be divided into a flat receiving plate that can be placed and moved.On the other hand, the upper male mold to be clamped with the lower female mold has the lower female mold inside. In this configuration, an edge portion for forming a shear edge of the lower female mold together with the lower mold portion for molding the stacked body accommodated by the receiving plate is provided.

Therefore, in the above configuration, when the upper male mold and the lower female mold are opened, the receiving plate can be removed by moving the receiving plate horizontally from the lower mold part.
Further, since the receiving plate is flat, it can be easily taken out from the receiving plate.

Therefore, the above-mentioned structure can omit the operation by the eject pin and the manual operation by the suction cup and the like, which are conventionally required, and can easily remove the obtained resin molded product from the mold. To play.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of a compression molding die according to the present invention.

FIG. 2 is a perspective view of a receiving plate of the compression molding die.

FIG. 3 is a front view of a laminate and a receiving plate used in the compression molding die.

FIG. 4 is a front view when the receiving plate is heated.

FIG. 5 is a plan view when the receiving plate is attached to a lower mold.

FIG. 6 is a cross-sectional view of a main part when the compression molding die is clamped.

FIG. 7 is a front view showing a state in which a laminate is placed on a receiving plate as a comparative example and the laminate is heated.

[Explanation of symbols]

 Reference Signs List 1 laminated body 2 receiving plate 3 lower mold 3a shear edge 3e lower female mold 4 upper male mold 4b rising part (edge part)

Claims (1)

(57) [Claims] 1. A compression molding die for forming a resin molded product by compression molding a laminated body in which a sheet-like material made of a thermoplastic resin containing a fibrous material is overlaid with an upper male mold and a lower female mold. In the above, the lower female mold can be divided into a fixed lower mold part and a flat receiving plate on which the stacked body can be placed and movable. The mold has an edge portion that forms a shear edge of the lower female mold together with the lower mold portion for clamping and forming the stacked body accommodated in the lower female mold by the receiving plate. A compression molding die, characterized by being made.