JPS61193825A - Method of heating foamed sheet in molding sheet - Google Patents

Abstract

PURPOSE:To prevent a foamed sheet from being deformed, displace or disaligned when the molding is effected, by arranging heaters on opposite sides of a foamed sheet, and interposing each heat screening member between the heater and the foamed sheet so that parts of the foamed sheet may be formed with non- heated sections corresponding to the configuration of the heat screening member. CONSTITUTION:A plurality of open spaces 51 each of which is in the shape of a square and are formed in the middle part of each heat screening member 5 and are arranged in the form of a lattice. A foamed sheet (S) is intermittently moved in accordance with the molding timing of molds 2, 3. When the foamed sheet (S) is moved one step to be fed into a heating furnace 1, upper and lower heat screening members 5 are moved toward the foamed sheet (S) and then are kept with a certain interval between the surfaces of the foamed sheet (S) and the members 5. Then the foamed sheet (S) is heated. After the heating step, the foamed sheet (S) is fed to molds 2, 3 where it is molded in a prescribed manner. Since the foamed sheet (S) is little heated and is secondarily foamed hardly at the non-heated sections (b), the foamed sheet (S) has enough rigidity and strength and would neither be deformed nor expanded by the softening.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a method of heating a foamed sheet in sheet molding, in which a heated and softened foamed sheet is bulged and deformed along a mold to form a predetermined molded product shape. , relates to a heating method for heating and softening a foamed sheet as a raw material in so-called sheet molding.

<Prior art> In the above-mentioned sheet molding, the raw material of the foamed sheet is heated to a softening temperature at which it can be molded using a heating furnace or the like, and then
The foamed sheet is fed to a mold for sheet molding, and the foamed sheet is molded into a predetermined molded product shape.

However, foamed sheets heated and softened in the heating process become slack or deformed due to softening, making it difficult to transport and handle from the heating process to the molding process, and it is difficult to accurately place the foam sheet in the mold during the molding process. There was a problem that was difficult to solve.・In particular, in the heating process, it would be good if the entire surface of the foam sheet could be heated uniformly, but normally, due to the arrangement and structure of the heating heater, uneven heating inevitably occurs, and each part of the foam sheet is heated differently. There is a problem in that the amount of deformation and expansion may be different or uneven, resulting in deformation or movement of the entire foam sheet.

In addition, when using a foam sheet that has been printed with characters or patterns, or colored, and the printed pattern or color scheme needs to be accurately distributed at a certain position on the molded product, the foam sheet can be heated as described above. Due to the deformation, the printed pattern etc. may be misaligned or moved, and may not be placed in the predetermined position of the mold, resulting in printing misalignment on the finished molded product.

<Purpose> Therefore, the purpose of the present invention is to solve the problems of the prior art described above, eliminate deformation and movement of the foam sheet during the heating process, facilitate handling of the foam sheet, and prevent misalignment of the molding position during molding. We are trying to develop a heating method that can eliminate this problem.

<Structure> And as a method for achieving the above object, when heating and softening the foam sheet used for sheet forming, a heat shielding member is placed between the heating heater installed on both sides of the foam sheet and the foam sheet. is interposed to block thermal radiation from the heating member, and a non-heating portion having a shape corresponding to the heat shielding member is formed in the - section of the foam sheet.

<Example> Next, an example of the present invention will be described below with reference to the drawings.

Fig. 1 shows the overall structure of a molding apparatus for carrying out the IJ method of the present invention, and the foam sheet (S) such as a foamed polystyrene sheet used for molding is a long rolled sheet. It is possible to sequentially pull out the molds from (It) and perform the heating S [step J3 and molding process] continuously on the line.

(1) is a heating furnace, which is configured such that a foam sheet (S) runs inside the tunnel-shaped heating furnace (1), and a pair of heating heaters (1) installed above and below the foam sheet (S).
0) From (10), irradiate far infrared rays with high heating efficiency to simultaneously heat both sides of the traveling foam sheet (S),
It can be heated and softened to a predetermined molding temperature.

Next, (2) and (3) are molds, which are installed adjacent to the heating furnace (1).The female mold ( 2), male molds (3) are provided at the bottom, which can be raised and lowered by a cylinder mechanism, etc., and the foamed sheet (S) heated and softened in the heating furnace (1) is placed in the upper mold (3). 2) In order to form a molded product having a shape along the molding die (2) (3) by sandwiching the mold (31), a predetermined molding process is performed.
Molding mold (2) (31) has a plurality of mold shapes arranged in order to mold a plurality of molded products at the same time, and performs so-called multi-cavity molding.

(4) is a conveyance mechanism, which uses a chain conveyor, etc. to pull out the foam sheet from the roll (R) and run the foam sheet (S) from the heating furnace (1) to the mold (21 (3)). iiQM is installed so that it passes through the center of the molds (2) and (3) from inside the heating furnace (1), and the conveyance mechanism is equipped with appropriate clamping means for clamping the side edges of the foam sheet (S). is formed.

The overall structure of the forming apparatus as described above is substantially the same as that of a conventional sheet forming apparatus, and may be modified to various structures used in known forming apparatuses.

In the case of this invention, inside the heating furnace (1), the foamed sheets 1 to (S) and the upper and lower heating heaters (10) (
A heat shielding member (9) is installed between each of the heat shielding members (9). It is movably attached so that the heat shielding member (5) can be freely moved toward or away from the foam sheet (S).

The detailed structure of the heat shielding member (5) is shown in FIG. In addition to forming a plate shape, a heat shielding member (i
"It is formed in the shape of a lattice frame in which a large number of rectangular through spaces (51) are formed. These through spaces (51) are formed in the mold (2) ( 3
), and is formed at a location corresponding to the part to be subjected to the molding process. Therefore, the penetrating space (
The lattice frame-shaped heat shielding members (S) other than 51) correspond to the outer periphery of the portion of the foamed sheet (S) that is subjected to the above-mentioned molding, and corresponds to the peripheral portion that is not subjected to the molding process.

A molding method using a molding apparatus having the above configuration will be described.

First, the foam sheet (S) is moved intermittently in accordance with the molding timing in the mold (21 (31).

That is, when the mold (21(3)) is closed, the foam sheet (S
) is not run, and when the molds (2) and (3) are opened, the foam sheet (
S) Only run intermittently. When the foam sheet (S) travels, the heat shielding member (5) in the heating furnace (1) is placed at a position away from the surface of the foam sheet (S).

Next, the foam sheet (S) of the first-stage valve moves to the heating furnace (
1), the upper and lower heat shielding members (S) are moved closer to the foam sheet (S) and placed with a certain gap provided between them and the surface of the foam sheet (S). .

Then, the foam sheet (S) is heated by the heating heater (10).
However, the heat shielding member (of the foam sheet (S)) is heated.
The portion corresponding to S is not heated because the heat irradiation from the heating heater (10) is blocked.

Therefore, only the portion of the foam sheet (S) corresponding to the through space (50) of the heat shielding member (51) is covered with the heating heater (10).
), it softens and at the same time causes secondary foaming.

That is, as shown in FIG. 3, the foam sheet (S) has a non-heated portion (b) corresponding to the heat shielding member (5) and a penetrating space (50) of the heat shielding member (5). Heating part (a
) occurs, and the heated part (a) is heated to the predetermined molding temperature and softened, but the unheated part (b) is not directly heated, so it hardly softens and secondary foaming does not occur. do not have. Furthermore, since the heated portion (a) that undergoes softening and deformation is surrounded by the non-heated portion (b) that does not undergo softening and deformation, the foam sheet (S) as a whole hardly ever deforms.

The foamed sheet (S) that has undergone the heating process as described above is supplied to the molds (2) and (3), and subjected to a predetermined molding process. In addition, when the foam sheet (S) is moved from the heating furnace (1) to the molds (2) and (3), the heating furnace (
1), move the heat shielding member (50) away from the surface of the foam sheet + 3), and then move the heat shielding member (50) within the running foam sheet (
The heat shielding member (50) is kept from contacting S).

In the above molding process, what is molded in the molds (2) and (3) is the softened heated part (a) of the foam sheet (S), and the unheated part (a) which is not softened at all. b
) are non-molded parts such as scrap parts that are not used as molded products.

In the above-mentioned method of the present invention, the foamed sheet (S) used for molding may be any foamed sheet made of polystyrene, polyethylene, polypropylene, and various other thermoplastic resins used in normal sheet molding. Can be used for Furthermore, a multilayer sheet in which a non-foamed thermoplastic resin film is laminated on the foamed sheet can also be used.

The foamed sheet (S) is preferably printed with a color scheme such as a pattern or letters that corresponds to the finished shape of the molded product.

Next, the heat shielding member (50) installed in the heating furnace (1) of the molding device is as follows for the foam sheet (S):
In order to form a non-heated portion (b) that blocks thermal radiation from the heating heater (10), it is preferable to use a material that has good reflectivity for heat rays. In order to prevent the heat shielding member (50) from heating up and increasing its temperature, if a device equipped with a cooling mechanism such as cold piping is used, the heat shielding member (50) heated by the heating heater (10) can be heated. This is preferable since the foamed sheet (S) is not heated indirectly. In addition, the surface of the heat shielding member (50) is treated with fluororesin to improve slippage so that it does not get caught even if it comes into contact with the foam sheet (S) when it comes close to the foam sheet (S). You can also apply

Gap (C) between heat shielding member (50) and foam sheet (S)
It is effective to carry out heating so that the area is within the range of 0 to 10 m1, since the non-heated part (b) and the heated part (a) can be clearly separated and formed. However, if the heat shielding member (50) approaches the foam sheet (S), there is a risk that it will come into contact with the foam sheet (S) or impede the running movement of the foam sheet (S), so the heat shield member (50) It is necessary to improve the slippage.

Further, as in the illustrated embodiment, if the elevating mechanism (51) is provided and the heat shielding member (50) is formed to be freely variable at different times, it will be possible to cope with the heating and the movement of the foam sheet (S). , or depending on the thickness of the foam sheet (S), a heat shielding member (
50) and the foam sheet (S) can be changed, which is convenient.

Next, the shape of the heat shielding member (9) and the through space (50) can be changed as appropriate depending on the shape and arrangement of the molded product. A heat shielding member (9
By forming a through space (50) in the foam sheet (S) and sufficiently heating and softening the foam sheet (S), a heated portion suitable for molding (
a), and a heat shielding member (S) is placed at other locations to block the radiant heat from the heating heater (1G) to the foam sheet (S) at the location, and to protect the foam sheet (S) from being heated and softened. , the non-heated part (b) may be formed. However, even if the part of the foam sheet (S) to be formed does not require a large deformation process, it may be partially heat-shielded. In some cases, it is covered with the member (5) to form a non-heated part (b).Also, even if it is a part not used for molding, a part of it is not covered with the heat shielding member (S) and is made into a heated part (a). You can leave it as

Specifically, when molding is performed using a multi-cavity mold (2) (3) as shown in the figure, a through space (such as a rectangular shape) corresponding to the outer peripheral shape of each molded product is formed. It is preferable to use a lattice frame-shaped heat shielding member (S) in which 50) are formed in parallel.That is, a lattice frame-shaped non-heating member is placed on the back of the foam sheet (S) and on the outer periphery of each molded product. By forming part (b), the foam sheet (S) metal body will not be significantly deformed or the part that will be formed into a molded product will not move, and the molding of each molded product can be easily performed. The position can be set accurately, and deformation, warpage, distortion, etc. of the entire foam sheet (S) can be well suppressed by the lattice frame-shaped non-heated portion (b).

In addition, as for the specific dimensions of the above-mentioned lattice frame-shaped heat shielding member ((g)), in FIG. It will be carried out in

Furthermore, the heat shielding member (in the modified example of 9, shown in FIG. 4,
The square opening space (
50), there is a pattern in the shape of an animal silhouette (
52). When this heat shielding member (5) with a pattern (52) is used, the foam sheet (S) has a fifth
As shown in the figure, a patterned non-heated part (b') corresponding to the shape of the patterned part (52) of the heat shielding member (5) is formed in the center of the lattice frame-shaped non-heated part (b). be done. and,
The molded product produced by molding also has a pattern formed by the non-heated portion (b'), which has a kind of design effect, as well as the non-heated portion (b') that did not cause secondary foaming.
Since b') has excellent rigidity and strength, it also has the effect of reinforcing the molded metal body.

For example, the waist strength without the pattern part (52) is iomm.
The above pattern part (52) for 0.8 to 1.0 ka in compression
When using the attached heat shielding member (5), the waist strength is 0°9~
The strength was increased by about 10% to 1.1kG.

Furthermore, the molds (2) (3) in the molding device can be freely constructed with the structure of molds used in conventional sheet molding, and either one of the molds (2) (31) can be used.
It is also possible to use a molding device that performs vacuum molding in which vacuum suction is performed or pressure molding in which compressed air is sprayed. In addition to a chain conveyor, various conveyor mechanisms can be used as the conveyance mechanism (4). As a means for clamping the foam sheet (S) to the conveyance mechanism (4), a means for clamping the ends of the foam sheet (S), or a means for clamping the foam sheet (S) to the transport mechanism (4) is used.
S) can be carried out by appropriately changing known clamping means, such as clamping by inserting a needle into S).

Furthermore, the foamed sheet (S) can be produced by heating and forming the foamed sheet (S) by heating and shaping it by intermittently running it wound around a long unrolled material (R), or by pre-rolling the foamed sheet (S) into a unit length. 1 in a single plate shape! It can also be applied to products that use cut veneer sheets and are molded at °C.

Effect> According to the method of the present invention configured as described above, in the heating step of heating and softening the foam sheet (S) to a predetermined temperature necessary for molding, the temperature between the heating heater (10) and the foam sheet (S) is A heat shielding member (5) is interposed in the foam sheet (S), and a heating heater (1
0) and partially unheated part (b
).

In the non-heated portion (b), the foamed sheet (S) hardly softens and does not cause secondary foaming, so it has sufficient rigidity and does not undergo deformation or expansion due to softening.

Therefore, the non-heated portion (b) can prevent the entire foam sheet (S) from deforming, and can prevent the foam sheet (S) from loosening or moving.

By preventing the entire foam sheet (S) from deforming or moving, the foam sheet (S) is transferred from the heating process to the molding process.
S) is easier to transport and handle, and the mold (2)
(3) The foam sheet (S) can be set accurately, the molded product can be molded in a fixed position on the foam sheet (S), and the finished quality of the molded product can be improved.

For example, in the conventional heating method, the positional deviation of the center of the molded product was 5 to 20o+i, but in the case of the heating method of the present invention, the positional deviation was 2 to 51, which is far less, and accurate molding can be performed. Ta.

In particular, when using a foam sheet (S) that has been printed in advance, the foam sheet (S) does not deform or move, so the printed pattern etc. It can be placed accurately in the position of the molded product, and the printed pattern can be displayed in the fixed position of the manufactured molded product, which is highly effective in improving the quality of the molded product and increasing the product value. Can be done.

[Brief explanation of drawings]

The figures show an embodiment of the present invention, in which Figure 1 is a structural diagram of the entire molding device, Figure 2 is a perspective view of a heat shielding member, and Figure 3 is a perspective view of a heat shielding member.
The figure is a plan view of the foam sheet after heating, FIG. 4 is a perspective view of a modified example of the heat shielding member, and FIG. 5 is a plan view of the foam sheet after heating. (1)... Heating furnace, (10)... Heating heater, (21 (3)... Molding mold, (4)...
Old...transport mechanism, (5)...heat shielding member, (5
0)...Penetration space, (51)...Elevating mechanism, (52)...Pattern, (S)...
・Foam sheet, (a)...Heating part, (b)・
...Non-heated part. Patent Applicant Sekisui Plastics Co., Ltd. Figure 3 q Figure 4 Raf Figure 5

Claims (1)

[Claims] 1. Processing the foam sheet used for sheet molding When heat softening, apply on both sides of the foam sheet. Between the installed heater and foam sheet A heat shielding member is interposed between the The foam sheet blocks heat radiation from the heater. A part of the frame has a shape that corresponds to the heat shielding member. It is characterized by forming a non-heating part of Addition of foam sheet in sheet molding heat method. 2. Among foam sheets, the foam formed during sheet molding Corresponds to the shape of the part to be shaped Frame-shaped heat shield with a through space The parts are heated with a heater and a foam sheet. Formed out of the foam sheet with intervening A frame-shaped non-stick is placed around the outer periphery of the part to be processed. The above claims forming a heating part Foamed silicone in sheet molding described in item 1 How to heat the oven. 3. Of the foam sheets, the foam formed during sheet molding At the position corresponding to the part to be shaped The heat shielding member on which the pattern is formed is heated. interposed between the heater and the foam sheet, Foamed sheets that are processed by molding Form a patterned non-heated part on the part Sheet according to claim 1 above Method of heating foam sheets during molding. 4. Move the heat shielding member towards the foam sheet It can be formed freely, and the foam sheet can be heated and transferred easily. During operation, the gap between the heat shielding member and the foam sheet The scope of the above patent claims that changes the size between Foaming in sheet molding as described in box 1 How to heat the sheet.