JP3126309B2 - Molding method of panel-shaped molded body containing core material - Google Patents

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 panel-shaped molded article made of synthetic resin, and more particularly to a molding method suitable for molding a panel-shaped molded article containing a core material in which a core material is sealed in a hollow interior.

[0002]

2. Description of the Related Art Conventionally, as a method of molding a synthetic resin hollow molded article, a so-called sheet blow molding method in which two heated resin sheets are sandwiched between a pair of molds and air is blown therebetween. A so-called molding method is known. Since the panel-shaped molded article obtained by this molding method has a completely hollow structure, it is light in weight, and can be obtained in a relatively large size and a large area. Therefore, it is widely used as various panel-shaped structural materials.

[0003] However, the conventional panel-shaped molded body has a drawback that it is generally vulnerable to external stress due to its hollow structure as described above. The present inventors previously used a sheet blow molding method to improve this point, and in the course of the molding operation, arranged a core material between two thermoplastic synthetic resin sheets and removed the core material. We have proposed a sheet-blow molding method with a core material that can be contained. That is, FIG.
As shown in (a), two sheets of synthetic resin (51) (5)
2) Arrange the core material (56) between the two sheets (51) and (52) and clamp them from above and below with the clampers (54a) and (54b) through the spacers (53) with the peripheral edges of the sheets (51) and (52) closed. Space (5
After forming 5), both sheets (51) and (52) are heated from above and below by heaters (57a) and (57b) to soften, and the air nozzle (5) provided in a part of the spacer (53) as appropriate.
Compressed air is blown into the closed space (55) from 8) to pretension both sheets (51) and (52) in the direction away from each other. Next, in this heat-softened state, as shown in FIG.
Close both molds (59) and (60) to the predetermined closed position so that both sheets (51) and (52) are sandwiched between a pair of upper and lower molding dies (59) and (60) inside the clamp position on the periphery. Then, both sheets (51) and (52) are sandwiched between the sheet sandwiching surfaces (59a) and (60a) on the periphery thereof, and their peripheral portions are joined and integrated. Further, as shown in FIG. 5 (c), the compressed air introduction nozzle (61) provided in the upper mold (59)
Is made to penetrate and penetrate the upper sheet (51) to be inserted into the closed space (55) between the two sheets (51) and (52), and then inserted into the closed space (55) through the nozzle (61). 55) Compressed air of a predetermined pressure is introduced into both sheets (5
1) Insert (52) into the cavity inside the mold (59) (60) (5
9b) Closely adhere to (60b). After cooling while maintaining the internal pressure between the two sheets, the compressed air introduction nozzle (61) is retracted to open both the dies (59) and (60) to take out the panel-shaped molded body and complete the molding operation. It is.

[0004]

The molding method proposed by the above-mentioned proposal is an excellent technique for making a panel-shaped molded product containing a core material into a molded product having higher added value by using a conventional sheet blow molding method. Although it is based on thought, subsequent studies by the inventors have revealed that there are still the following problems to be improved. The first problem is FIG.
As shown in (a), since the core material (56) is directly placed on the thermoplastic synthetic resin sheet (52), as shown in FIG. The position of the core material deviates from the predetermined position (p) so that the core material cannot be accurately sealed, or as shown in FIG. 7, the position of the core material greatly deviates, and the two sheets by the molds (59) and (60) are used. (51) The position (e) is sandwiched between the (52) and hinders the fusion of the two sheets (51) and (52). The second problem is that, depending on the weight of the core material (56) as shown in FIG. 8, the droop of the sheet (52) at the time of heating increases, so that not only a uniform heating operation cannot be performed but also the lower heater (57b). The weight of the core (56) and the hot tensile strength of the sheet (52) are relatively greater in the former case and smaller in the latter case, which is increasingly promoted.

[0005] The present invention solves the above-mentioned problems in the above proposal, prevents the core material from shifting, secures the correct position thereof, and suppresses the droop of the thermoplastic synthetic resin sheet. Further, it is an object of the present invention to provide a molding method capable of obtaining a large-sized, large-area panel-shaped molded product containing a core material.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a core material is disposed between two opposing thermoplastic synthetic resin sheets at a predetermined interval, and the peripheral edges of both sheets are pressed by a clamper to close the core. After forming a space and heating and softening the two sheets, the sheet is sandwiched between a pair of upper and lower molds inside the clamping position on the periphery, and in a method of forming a core-containing panel-shaped molded body to be blow-molded, A gas permeable heat resistant support member is stretched on the side sheet, and the core material is placed on the gas permeable heat resistant support member at a position where the core material is sealed between the two sheets in the cavity of the mold. The gist of the present invention is a method of forming a core-containing panel-shaped molded body, which comprises performing a molding operation.

The present invention will be described below with reference to the drawings.

First, as shown in FIG. 1 (a), two thermoplastic synthetic resin sheets (1) used as molding materials
(2) When arranging the core material (6) between the two sheets (1)
One layer of a heat-resistant heat-resistant support member (S) parallel to both sheets is stretched over the entire area between (2), and the core material (6) is placed on the heat-resistant heat-resistant support member (S). After that, the clampers (4) at their peripheral portions via the spacers (3).
a) The sheets (1) and (2) are sandwiched by (4b) and heated from above and below by heaters (7a) and (7b) while maintaining both sheets (1) and (2) in a state of forming a closed space (5) therebetween. This is softened. At this time, in order to correctly seal the core material (6) at a predetermined position between the two thermoplastic synthetic resin sheets (1) and (2) via both sheets (1) and (2), This is preliminarily placed on the air-permeable heat-resistant support member (S)
Place in the correct position above.

[0009] The thermoplastic synthetic resin sheets (1) and (2)
The upper sheet (1) is supported by the air-permeable and heat-resistant support member (S) together with the core material (6) so that the lower sheet (2) is closed. (5) The droop is suppressed together with the upper sheet by balancing the internal pressure and the atmospheric pressure. In this case, when the sheets (1) and (2) are softened, compressed air is blown into the closed space (5) from the air nozzle (8) provided in a part of the spacer (3) to blow the sheets (1) and (2). )
(2) can be pre-stretched in the direction away from each other, or conversely, excess air corresponding to the volume of the core material (6) in the closed space (5) can be removed from the air nozzle (8).

When both sheets (1) and (2) reach a predetermined softening temperature, as shown in FIG.
(2) The pair of upper and lower molding dies (9) and (10) are moved to a predetermined closed position together with the air-permeable heat-resistant support member (S) on which the core material (6) is placed, inside the peripheral clamping position. Then, the sheets are brought closer to each other, and sandwiched between the sheet sandwiching surfaces (9a) and (10a) on the peripheral edge thereof to be joined and integrated.

Further, the compressed air introducing nozzle (11) provided in the upper mold (9) is advanced to make it penetrate and penetrate into the upper sheet (1), so that the closed space (5) is inserted. 1), compressed air of a predetermined pressure is introduced into the closed space (5) through the compressed air introduction nozzle (11), and the two sheets (1) and (2) are inserted as shown in FIG. The molds (9) and (10) are brought into close contact with the inner surfaces (9b) and (10b) of the cavities. Then, after cooling while maintaining the internal pressure between the two sheets (1) and (2), the compressed air introduction nozzle (10) is retracted and the two molds (9) (1)
0) is opened and the hollow molded body is taken out to complete the molding operation.

As the core material used in the present invention, any material can be used as long as it is a light-weight plate-like body having a structure that does not hinder sheet blow molding and has heat resistance. In terms of material, for example, heat-resistant synthetic resin, paper, organic materials such as wood, and metals, glass, asbestos, ceramics, inorganic materials such as gypsum or a composite material thereof, and in the shape direction, in the thickness direction Panel-shaped honeycomb structures, porous structures, columns, frames, corrugates, and the like that are open are exemplified. In particular, the honeycomb structure is suitable for reducing the weight of the target panel-shaped molded body and improving the surface load resistance, heat insulation, soundproofing, and the like of the panel-shaped molded body.

In order to ensure the flow of compressed air at the time of blow molding, irregularities and corrugations are provided on the front and back surfaces of the core material to form a communication gap between the thermoplastic synthetic resin sheet and the core material. Alternatively, the core material may be divided into a plurality of parts. Furthermore, in the honeycomb structure that opens in the thickness direction,
If a vent is provided in the wall, there is no possibility that the blow molding will be hindered.

Next, as the gas-permeable and heat-resistant support member used in the present invention, a net-like or cord-like member having a flat shape when stretched and developed around the periphery is used. The one that does not cause a problem is good. In addition, the core material can be supported at the time of blow molding, and at the same time as the temperature at the time of blow molding, that is, at a temperature of about 100 to 220 ° C., when the thermoplastic synthetic resin sheet is heated and softened and hangs down, it can be supported. Any material that can be used and that does not cause softening or deformation itself can be used. Further, in the case of a mesh, the size of the mesh, and in the case of a string, the interval between parallel or crossed strings is large as long as it is large enough to support the thermoplastic synthetic resin sheet in the heat-softened state with the core material. The size depends on the shape and size of the target core-containing panel-shaped molded product, the material and form of the core material, the type, thickness, and molding temperature of the thermoplastic synthetic resin sheet used. I can decide. Furthermore, the thickness and number of the net and the string may be any thickness and number within a range where the net and the string are not embedded in the joint of the panel-shaped molded body and the joining strength of the joint is not reduced. As a material, for example, a material made of a natural organic material such as cotton thread, silk thread, and hemp thread, a synthetic organic material such as thermosetting resin and heat-resistant rubber, and an inorganic material such as glass fiber and metal fiber are applied.

As described above, the air-permeable and heat-resistant support member (S) according to the present invention serves to maintain the core member (6) at an accurate position during the sheet blow molding process, and serves to heat and soften and hang down. Plastic synthetic resin sheet (1)
It plays the role of supporting (2). Then, as shown in FIG. 2A, the mode of stretching the gas-permeable and heat-resistant support member (S) is usually between the lower sheet (2) and the spacer (3). In the preparation stage of the molding process, a gas-permeable heat-resistant support member (S) is stretched on the lower sheet (2) in a rigid state at room temperature, and then the core material (6) is attached to the gas-permeable heat-resistant support member (S). It is easy to prepare for the molding operation because it is placed on a free surface on the core material (6).
There is an advantage that the position can be easily adjusted. But,
Depending on the weight and the shape of the core material (6) to be used, it is necessary to sufficiently fix the peripheral portion so that the air-permeable heat-resistant support member (S) is not excessively loosened by mounting the core material (6). In this case, as shown in FIG. 2 (b), a gas-permeable and heat-resistant support member (S) is provided with a peripheral portion formed of a spacer (3).
Alternatively, for example, it can be stretched while being pinched by a pressing member (3p) that fits with this.

Further, as described above, since the core member (6) is placed in a free state on the normally stretched heat-resistant heat-resistant support member (S), the core member (6) is slightly displaced. Is possible, but this displacement is automatically corrected by the approach of the upper and lower dies (9) and (10). However, when the position of the core material (6) is more accurately required, a part of the core material (6) is bonded to the air-permeable heat-resistant support member (S) with an adhesive or a thread.
It may be fixed each time or in advance.

Incidentally, as shown in FIG.With core material
Panel-shaped molded body(F) is trimmed at the joint (d)
After being used for the intended purpose,
The breathable heat-resistant support member (S)Panel-shaped molded body with core material
(F).

[0018]

Next, an embodiment of the present invention will be described.

Example 1 The target panel-shaped molded product containing a core material had a dimension of width 5
It was a thin, wide-area plate-like body having a thickness of 00 mm, a length of 800 mm, and a thickness of 25 mm.

First, a pair of molds and other molding apparatus members corresponding to the above-mentioned target dimensional specifications, and a paper honeycomb having a vent having a wall with a thickness of 21 mm, a development width of 490 mm, and a development length of 790 mm as a core material. Prepared and used as a thermoplastic synthetic resin sheet as a molding material for a panel-shaped molded article, a width of 700 mm, a length of 1000 mm, and a thickness of 2.0 m
m modified acrylic high impact PVC plate (manufactured by Tsutsunaka Plastics Industry Co., Ltd., trade name “KAIDAK”) part number KDG120
0) were prepared.

Further, as the heat-permeable and heat-resistant supporting member, a width of 6
A 3-mesh glass fiber net having a size of 00 mm and a length of 900 mm was prepared.

Next, in accordance with the order shown in FIG. 1A, the lower clamper (4b), the lower acrylic-modified high-impact PVC plate (2), the air-permeable heat-resistant support member (S), and the core material Each member of the paper honeycomb (6), the spacer (3), the upper acrylic-modified high-impact PVC plate (1), and the upper clamper (4a) is composed of a core material (6) and both sheets (1).
After being adjusted to a predetermined position that can be properly sealed in the cavities of the molds (9) and (10) via (2), they are sequentially placed and clamped by the clampers (4a) and (4b), and then the sheet is The surface was heated to 180 ° C., and was molded according to the molding operation of a usual sheet blow molding method. In addition, acrylic modified high impact PVC plate in the molding process (1)
The hanging amount of (2) was supported by the air-permeable and heat-resistant supporting member (S), and was only 4 cm at the maximum, and there was no problem in the molding operation. The shape of the mold cavity inner surface (9b) (10b) is accurately reproduced in the obtained panel-shaped molded product containing the core material.
There were no defects such as wrinkles. In addition, at the joint of the core-containing panel-shaped molded product after trimming, the peripheral portion of the air-permeable heat-resistant support member is embedded and the cut end surface is exposed, but the joining strength of the core-containing panel-shaped molded product is reduced. Has no effect,
It was kept high in a range where there was no practical problem.

Example 2 The dimensions of the core-containing panel-shaped molded product were the same as in Example 1, and two core materials (6 ') (6
3), as shown in FIG. 3, was placed on the air-permeable heat-resistant support member (S) at a distance (L) of 30 mm from each other in the length direction, and was fixed thereto using an adhesive. Others
Sheet blow molding was performed in exactly the same manner as in Example 1. The amount of droop of the acrylic-modified high-impact PVC plates (1) and (2) in the molding process was the same as in Example 1, and there was no problem in the molding operation. The obtained panel-shaped molded product containing a core material accurately reproduces the shapes of the inner surfaces (9b) and (10b) of the mold cavity and has no defects such as wrinkles.
The core members (6 ') and (6') were sealed in the correct positions. Further, at the joint of the core-shaped panel-shaped molded body after trimming, the peripheral portion of the gas-permeable heat-resistant support member is buried and the cut end surface is exposed. Without affecting the bonding strength of the shaped body
It was kept high in a range where there was no practical problem.

[0024]

As described above, according to the present invention, it is possible to prevent the core material from shifting, to secure the correct position thereof, and to suppress the droop of the thermoplastic synthetic resin sheet due to softening by heating. Even with a large-sized, large-area panel-shaped molded product containing a core material, the reproducibility of the molded shape is high, and the strength of the joint can be made high. The applicable range of the molding method can be significantly expanded. In addition, since the shape, number, and arrangement of the core material can be freely selected, the structure of the core-shaped panel-shaped molded product can be varied, and this kind of core-shaped panel-shaped molded product can be obtained. There is an effect that the use can be expanded.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a molding step in a molding method of a panel-like molded body containing a core material according to the present invention, and FIG.
1 shows a state in which the molding material is heated, FIG. 1B shows a state in which the periphery of the molding material is joined and integrated by a molding die, and FIG. 1C shows a state in which compressed air is introduced to perform molding. .

FIG. 2 shows the manner in which the heat-resistant and heat-permeable support member used in the present invention is stretched in relation to a core material.
Fig. 2 shows the case where it is stretched by clamping.
(B) is a cross-sectional view showing a case where the spacer is stretched using a spacer.

FIG. 3 is a partially omitted cross-sectional view of a core-containing panel-shaped molded product obtained by the present invention.

FIG. 4 is a cross-sectional view illustrating a relationship between a gas-permeable heat-resistant support member and a core material according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a forming step in a conventional method of forming a panel-shaped molded product containing a core material, wherein FIG. 5 (a) shows a state when a molding material is heated, and FIG. FIG. 5C shows a state in which the peripheral edges of the material are joined and integrated, and a state in which molding is performed by introducing compressed air.

FIG. 6 is a cross-sectional view showing a positional relationship between a core material and a thermoplastic synthetic resin sheet in a conventional method for forming a panel-shaped molded product containing a core material, and FIG.
(B) shows the state of displacement of the core material due to the droop of the thermoplastic synthetic resin sheet during heating.

FIG. 7 is a plan view showing a positional shift between a thermoplastic synthetic resin sheet and a core member in a conventional method of molding a panel-shaped molded product containing a core member.

FIG. 8 is a cross-sectional view showing a hanging state of a thermoplastic synthetic resin sheet at the time of heating in a conventional method of molding a core-containing panel-shaped molded body in relation to a heater.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Thermoplastic synthetic resin sheet 2 ... Thermoplastic synthetic resin sheet 3 ... Spacer 3p ... Holding member 4a ... Upper clamper 4b ... Lower clamper 5 ... Closed space 6 ... Core material 7a ... Heater (upper) 7b ... Heater (lower) 8) Air nozzle 9 ... Molding die (upper side) 10 ... Molding die (lower side) 11 ... Nozzle for introducing compressed air S ... Air-permeable heat-resistant support member F ... Panel-shaped molded body containing core material

Claims (7)

(57) [Claims] 1. A core material is arranged between two thermoplastic synthetic resin sheets facing each other at a predetermined interval, the peripheral edges of both sheets are pressed by a clamper to form a closed space, and the two sheets are heated and softened. After that, in the method of forming a core-containing panel-shaped molded body that is sandwiched between a pair of upper and lower molds inside the above-described pressure-pressing position of the periphery and blow-molded, a breathable heat-resistant support member is stretched on the lower sheet. Wherein the core material is placed on the air-permeable heat-resistant support member at a position where the core material is sealed between the two sheets in the cavity of the mold, and the subsequent molding operation is performed. A method for forming a panel-shaped molded body. 2. The method for molding a panel-like molded product containing a core material according to claim 1, wherein the air-permeable heat-resistant support member is stretched by attaching it to a spacer. 3. The method according to claim 1, wherein the air-permeable heat-resistant support member has a net-like form. 4. The molding method for a panel-shaped molded product containing a core material according to claim 1, wherein the heat-permeable heat-resistant supporting member is made of an inorganic material. 5. The method for forming a core-containing panel-shaped molded product according to claim 1, wherein the heat-permeable heat-resistant supporting member is made of a natural or synthetic organic material. 6. The method according to claim 1, wherein the core comprises a panel-like honeycomb-like structure. 7. The method for forming a panel-shaped molded product containing a core material according to claim 1, wherein the core material is fixed to a gas-permeable heat-resistant support member.