JP2003205527A - Method for molding synthetic resin sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for molding a good synthetic resin sheet, capable of performing three-dimensional processing of high accuracy and capable of reducing processing equipment cost and material cost. <P>SOLUTION: After the synthetic resin sheet 30 is set to the inside of a mold 100 so as to be arranged along the mold surface 10a of a lower mold 10, a molding resin 31 is injected in the cavity of the mold 100 from the gate 22 provided to an upper mold 20 to press-mold the synthetic resin sheet 30 along the surface shape of the mold surface 10a by the quantity of heat and molding pressure of the molding resin 31. Thereafter, a molded article comprising the molding resin 31 is released from the synthetic resin sheet 30 taken out of the mold 100. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for molding a synthetic resin sheet, and more particularly to a method for molding a synthetic resin sheet which is three-dimensionally processed on a synthetic resin sheet on which a printing design such as a picture or letters is printed.

[0002]

2. Description of the Related Art In recent years, automobile meter panels (instrument panels)
As shown in the figure, three-dimensional processing (a kind of squeezing processing) is applied to the synthetic resin sheet on which the printing design such as patterns and characters is printed,
There are some that have a three-dimensional design effect. As a method of three-dimensionally molding a synthetic resin sheet in this way, vacuum molding and pressure molding are generally known.
In these molding methods, the position of the printed design printed on the synthetic resin sheet and the uneven shape are likely to vary,
When accuracy of the position of letters and scales and the uneven shape is important, such as in a meter panel of an automobile, a high pressure molding method is often used.

7 to 10 show an example of a method of molding a synthetic resin sheet by a high pressure molding method. In this high-pressure molding method, as shown in FIG. 7, first, a lower mold 1 having a mold surface 1a corresponding to a desired concavo-convex shape (cavity surface shape) is formed on a synthetic resin made of a thermoplastic such as polycarbonate. Seat 2 is set. still,
The synthetic resin sheet 2 is preprinted with printing designs such as characters and scales.

Next, as shown in FIG. 8, the upper mold 3 is lowered to sandwich the synthetic resin sheet 2 between the upper and lower molds 3 and 1, and the synthetic resin sheet 2 is preheated at a temperature lower than the glass transition point. . Then, as shown in FIG. 9, the synthetic resin sheet 2
When high-pressure air (1 MPa or more) is supplied from the high-pressure air pump 6 to the space 3a between the upper mold 3 and the upper mold 3, the synthetic resin sheet 2 moves the mold surface 1a of the lower mold 1. And is molded along the uneven shape of the mold surface 1a.

At this time, the air between the synthetic resin sheet 2 and the lower mold 1 is the air vent hole 4 formed in the bottom of the lower mold 1.
Is discharged from the mold. After such molding, as shown in FIG. 10, the upper mold 3 is lifted to open the mold, and the molded synthetic resin sheet 2 is released from the mold surface 1a of the lower mold 1 to obtain a highly accurate unevenness. The synthetic resin sheet 2 having a finished shape is obtained.

Further, as a method for producing a synthetic resin molded product used by back-lighting, such as a meter panel of an automobile, for example, Japanese Patent Publication No. 5-21051 discloses "Synthetic resin molded product and The manufacturing method "is known. According to the method for producing a synthetic resin molded article disclosed in Japanese Patent Publication No. 5-21051, after an ink film layer is printed on a synthetic resin sheet and processed into a shape that can be loaded into a mold. , It is loaded so as to be adjacent to the inner surface of the mold, and after that, the mold is closed and then the molten resin for molding the molded product is injected into the mold to allow backwriting having a different surface layer or back surface layer. A synthetic resin molded product can be manufactured.

[0007]

However, in the conventional high-pressure molding method as described above, an expensive high-pressure air pump for supplying high-pressure air of 1 MPa or more into the mold is required, and dedicated processing equipment ( There is a problem that a high pressure molding machine is required and the equipment cost rises.

Further, in the manufacturing method disclosed in the above Japanese Patent Publication No. 5-21051, since a synthetic resin sheet which is a back lightable product in which a synthetic resin sheet and a molding resin are integrated is a product, There is a problem that the thickness of the product becomes thicker and the weight reduction is hindered, and the material cost is higher by the amount of the molding resin than the high pressure molding method.

Therefore, an object of the present invention is to solve the above problems, and to provide a good synthetic resin sheet capable of performing highly precise three-dimensional processing, reducing the processing equipment cost and the material cost. It is to provide a molding method.

[0010]

The above object of the present invention is to load a synthetic resin sheet into a molding die so as to extend along the surface of one cavity, and then to form the molding die corresponding to the surface of the other cavity. By injection molding or compression molding a molding resin in a mold, the synthetic resin sheet is pressure-molded along the one cavity surface shape by the heat amount and molding pressure of the molding resin, and then the molding metal. This is achieved by a method for molding a synthetic resin sheet, characterized in that a molded product of the molding resin is peeled from the synthetic resin sheet taken out from the mold.

According to the above construction, the molding resin is injection-molded or compression-molded in the molding die to press-mold the synthetic resin sheet by the heat amount and molding pressure of the molding resin, so that high pressure air is generated. The processing pressure can be made higher than the conventional high pressure molding method used. Therefore, the press-molded synthetic resin sheet has good reproducibility of the surface shape of one of the cavities to be pressed, and can obtain a highly accurate uneven shape.

Further, a conventional vacuum forming method utilizing gas,
In the case of the pressure molding method and the high pressure molding method, since gas leaks, holes cannot be formed in the synthetic resin sheet loaded in the molding die, but the synthetic resin sheet is pressed using the molding resin. In this case, the synthetic resin sheet may be provided with positioning guide holes. Therefore,
Accurate positioning of the synthetic resin sheet with respect to the molding die is facilitated by providing the molding die with projections for positioning the synthetic resin sheet and engaging the positioning projections with the guide holes of the synthetic resin sheet. Becomes

As the molding die, general-purpose equipment such as an injection molding machine and a compression molding machine can be used, and 1MP
There is no need for expensive equipment such as a high-pressure air pump that supplies high-pressure air of a or higher. Also, because the molded resin molded product is peeled off from the synthetic resin sheet taken out from the molding die, and only the synthetic resin sheet is used as the product, the thickness of the molded resin is reduced and the weight is reduced. Can be achieved. Further, the molded product of the molding resin after peeling can be repeatedly used by reprocessing.

Preferably, the synthetic resin sheet is made of an amorphous resin material and the molding resin is made of a crystalline resin material. Also, preferably the molding resin,
It is made of a molding resin material having a melting temperature lower than the melting temperature of the sheet material of the synthetic resin sheet. In these cases, the molded synthetic resin sheet and the molded product of the molding resin do not adhere to each other, and the molded product of the molding resin can be easily separated from the synthetic resin sheet.

Also, preferably, a printing design is printed in advance on the front surface side or the back surface side of the one cavity in the synthetic resin sheet. In this case, it is possible to obtain a synthetic resin sheet in which the position of the printed design and the desired uneven shape are finished with high accuracy.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for molding a synthetic resin sheet according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. 1 to 6 are schematic cross-sectional views of a molding die for explaining a method for molding a synthetic resin sheet according to an embodiment of the present invention. The synthetic resin sheet 30 in the present embodiment is a synthetic resin sheet made of a thermoplastic resin on which printing designs such as patterns and characters are printed in advance.

The molding die 100 used in the method for molding a synthetic resin sheet according to this embodiment is, as shown in FIG. It is an injection molding die for injecting a resin 31. On the upper surface of the lower mold 10, a mold surface (one cavity surface) 10a having a desired uneven shape is formed. An annular sheet pressing member 15 that presses the peripheral edge of the printed synthetic resin sheet 30 is fixed to the upper surface of the lower mold 10 by a bolt or the like not shown. Also, the lower mold 1
A hole 13 for venting air, which communicates with the mold surface 10a, is formed in the bottom portion of 0.

On the other hand, the concave portion 2 of the upper die 20 which is a movable die mounted on a movable plate (not shown) and driven up and down.
A gate 22 is provided so as to penetrate through the bottom portion of 1 (the surface of the other cavity). The gate 22 communicates with a nozzle of an injection molding machine (not shown) via the runner portion 23, and injects the molten molding resin 31 into the cavity formed by the upper and lower molds 10 and 20.

Further, as the material of the synthetic resin sheet 30 in this embodiment, a non-crystalline resin material such as polycarbonate or ABS resin is used, and as the material of the molding resin 31 injected from the gate 22 into the cavity. As the material, a crystalline resin material such as polyethylene, polypropylene, polyacetal, or a composite material thereof is used.

Further, the molding conditions (injection speed, melting temperature, etc.) of the molding resin 31, the shape and volume of the recess 21 are determined by the heat quantity of the molding resin 31 and the synthetic resin sheet 30.
It is appropriately set in consideration of the moldability and the like. Further, depending on the material of the synthetic resin sheet 30, the synthetic resin sheet 30 may be preheated at a low temperature below the glass transition point.

Next, a method of molding a synthetic resin sheet, which is pressure-molded into a desired uneven shape using the molding die 100 described above, will be described. First, as shown in FIG.
The synthetic resin sheet 30 is loaded on the upper surface of 0, and the peripheral edge is pressed by the sheet pressing member 15 to set.

Next, as shown in FIG.
Is lowered to clamp the upper and lower molds 10 and 20 to form a cavity 25. Then, as shown in FIG. 4, the molding resin 31 melted from the gate 22 is injected into the cavity 25 corresponding to the bottom of the recess 21 to move the synthetic resin sheet 30 to the molding resin 31.
Is pressed against the mold surface 10a of the lower mold 10 by the heat amount and the molding pressure, and pressure molding is performed along the mold surface 10a.

At this time, the air in the space between the synthetic resin sheet 30 and the mold surface 10a is discharged to the outside of the mold through the air vent hole 13 formed in the bottom of the lower mold 10. .
Further, an air vent (shallow groove) may be provided on the die dividing surface instead of the air vent hole 13.

Next, as shown in FIG.
And the upper and lower molds 10 and 20 are opened, the sheet pressing member 15 is removed as shown in FIG. 6, and the molded synthetic resin sheet 30 and the molded product 40 are separated from the mold surface 10a of the lower mold 10. After molding, the molded product 40 is peeled off from the synthetic resin sheet 30 to obtain the synthetic resin sheet 30 in which the position of the printing design and the uneven shape are finished with high accuracy.

At this time, the synthetic resin sheet 30 is made of an amorphous resin material such as polycarbonate or ABS resin, and the molded article 40 is made of a crystalline resin such as polyethylene, polypropylene, polyacetal, or a composite material thereof. Since the material is used, the synthetic resin sheet 30 and the molded product 40 after molding do not weld, and the molded product 40 of the molding resin can be easily separated from the synthetic resin sheet 30.

That is, according to the method for molding a synthetic resin sheet using the molding die 100 of the present embodiment, the molding resin 31 is injection-molded in the molding die 100 to thereby form the molding resin. Since the synthetic resin sheet 30 is press-molded by the heat quantity of 31 and the molding pressure, the processing pressure can be made higher than that of the conventional high-pressure molding method using high-pressure air as shown in FIGS. Therefore, the press-molded synthetic resin sheet 30 has good reproducibility of the surface shape of the mold surface 10a to be pressed, and can obtain a highly accurate uneven shape.

Further, a conventional vacuum forming method utilizing gas,
In the case of the pressure molding method and the high pressure molding method, since the gas leaks, it is not possible to form holes in the synthetic resin sheet 30 to be loaded into the molding die, but the synthetic resin sheet 30 is formed by using the molding resin 31. In the case of press molding, the synthetic resin sheet 30 may be provided with positioning guide holes.

Therefore, a positioning projection of the synthetic resin sheet 30 is projected on the molding die 100, and the positioning projection is engaged with a guide hole provided in the synthetic resin sheet 30 to form the molding die. Accurate positioning of the synthetic resin sheet 30 with respect to 100 can be facilitated. Therefore, even when printing designs such as characters and scales are previously printed on the synthetic resin sheet 30 such as a meter panel of an automobile, it is possible to further stabilize and improve the accuracy of the position and the uneven shape of these printing designs. it can.

Further, as the molding die 100, an injection molding machine which is a general-purpose equipment can be used, and expensive equipment such as a high-pressure air pump for supplying high-pressure air of 1 MPa or more is unnecessary. Further, since the molded product 40 is peeled off from the synthetic resin sheet 30 taken out from the molding die 100 and only the synthetic resin sheet 30 is used as the product, the thickness can be reduced by 40 minutes to reduce the weight. Can be planned. Further, the molded product 40 after peeling can be repeatedly used by reprocessing.

The constitution of the molding die and the kind of the synthetic resin sheet in the method for molding the synthetic resin sheet according to the present invention are not limited to those in the above-mentioned embodiment, and various kinds can be adopted based on the gist of the present invention. It goes without saying that it can take any form. For example, in the above-described embodiment, the synthetic resin sheet 30 and the molded product 40 are prevented from being welded after molding.
Although the synthetic resin sheet 30 is an amorphous resin material and the molding resin 31 is a crystalline resin material, instead of this, for example, the synthetic resin sheet 30 is a high temperature melting resin material such as polycarbonate, and the molding resin 31 is By using a low temperature melting resin material such as ABS resin or AS resin having a melting temperature lower than that of the polycarbonate or the like, the synthetic resin sheet 30 and the molded article 40 may be configured not to be welded after molding.

Further, in the above embodiment, the molding method of the synthetic resin sheet 30 having the printing surface is taken as an example, but it goes without saying that the present invention can be applied to a synthetic resin sheet having no printing surface. Further, in the above-described embodiment, the case where the synthetic resin sheet 30 is press-molded by the heat amount and the molding pressure of the molding resin 31 by injection molding is taken as an example, but instead of this, for example, the molding is performed by melting in a molding die. The synthetic resin sheet 30 can be pressed by the heat amount and the molding pressure of the molding resin 31 melted in the molding die by charging the molding resin 31 and performing compression molding.

[0032]

As described above, according to the method for molding a synthetic resin sheet of the present invention described above, the molding resin is injection-molded or compression-molded in the molding die to obtain the heat amount and molding pressure of the molding resin. Since the synthetic resin sheet is pressure-molded by the method, the processing pressure can be increased as compared with the conventional high-pressure molding method using high-pressure air. Therefore, the press-molded synthetic resin sheet has good reproducibility of the surface shape of one of the cavities to be pressed, and can obtain a highly accurate uneven shape.

Further, a conventional vacuum forming method utilizing gas,
In the case of the pressure molding method and the high pressure molding method, since gas leaks, holes cannot be formed in the synthetic resin sheet loaded in the molding die, but the synthetic resin sheet is pressed using the molding resin. In this case, the synthetic resin sheet may be provided with positioning guide holes. Therefore,
Accurate positioning of the synthetic resin sheet with respect to the molding die is easy by providing the molding die with projections for positioning the synthetic resin sheet and engaging the positioning projections with the guide holes of the synthetic resin sheet. Becomes

As the molding die, general-purpose equipment such as an injection molding machine and a compression molding machine can be used, and 1MP
There is no need for expensive equipment such as a high-pressure air pump that supplies high-pressure air of a or higher. Also, because the molded resin molded product is peeled off from the synthetic resin sheet taken out from the molding die, and only the synthetic resin sheet is used as the product, the thickness of the molded resin is reduced and the weight is reduced. Can be achieved. Further, the molded product of the molding resin after peeling can be repeatedly used by reprocessing. Therefore, it is possible to provide a favorable method for molding a synthetic resin sheet, which can perform highly accurate three-dimensional processing, and can reduce the processing equipment cost and the material cost.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a molding die for explaining a method for molding a synthetic resin sheet according to an embodiment of the present invention.

FIG. 2 shows a state where a synthetic resin sheet is set in the molding die shown in FIG.

FIG. 3 shows a state in which the upper and lower molds of the molding die shown in FIG. 2 are clamped.

4 shows a state in which a molten molding resin material is injected into a cavity of the molding die shown in FIG.

5 shows a state in which the upper and lower molds of the molding die shown in FIG. 4 are opened.

6 shows a state in which a molded synthetic resin sheet is released from the lower mold shown in FIG. 5 and a molded product of a molding resin is peeled from the synthetic resin sheet.

FIG. 7 is a schematic cross-sectional view of a molding die for explaining a conventional method of molding a synthetic resin sheet by a high-pressure molding method, showing a state where a synthetic resin sheet is set in a lower mold.

FIG. 8 shows a state in which the mold shown in FIG. 7 is clamped.

9 shows a state in which high pressure air is supplied to the space between the synthetic resin sheet and the upper mold shown in FIG.

10 shows a state in which the molding die shown in FIG. 9 is opened and the synthetic resin sheet after molding is released.

[Explanation of symbols]

10 Lower mold 10a mold surface 20 Upper mold 30 synthetic resin sheet 31 Molding resin 40 Molded resin products 100 Molds for molding

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroyoshi Oshiro             1-7-1 Yokoi Shimada City, Shizuoka Prefecture Yazaki Keiki Co., Ltd.             Inside the company (72) Inventor Makoto Kikukawa             1-7-1 Yokoi Shimada City, Shizuoka Prefecture Yazaki Keiki Co., Ltd.             Inside the company F term (reference) 4F204 FA01 FA15 FB01 FF01 FQ38                 4F206 AC03 AD09 AG03 AG05 JA07                       JB13 JL02 JM04 JN11 JQ81                       JW21

Claims (4)

[Claims] 1. A synthetic resin sheet is loaded into a molding die along one cavity surface, and then the molding resin is injection-molded or compressed in the molding die corresponding to the other cavity surface. By molding, the synthetic resin sheet is press-molded along the one cavity surface shape by the heat amount and molding pressure of the molding resin, and then the synthetic resin sheet taken out from the molding die A method for molding a synthetic resin sheet, which comprises peeling a molded product of a molding resin. 2. The method for molding a synthetic resin sheet according to claim 1, wherein the synthetic resin sheet is made of an amorphous resin material, and the molding resin is made of a crystalline resin material. 3. The method for molding a synthetic resin sheet according to claim 1, wherein the molding resin comprises a molding resin material having a melting temperature lower than a melting temperature of the sheet material of the synthetic resin sheet. . 4. The synthetic resin according to claim 1, wherein a printed design is printed in advance on the front surface side or the back surface side of the one cavity of the synthetic resin sheet. Sheet forming method.