JPH1177819A - Method and apparatus for bending processing of thermoplastic synthetic resin panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the impact strength of a bent part high and uniform by heating a thermoplastic synthetic resin panel to a predetermined temp. while bringing the same into contact with an elastic receiving mold under pressure before further allowing a bending upper mold to fall. SOLUTION: Bending processing for a thermoplastic synthetic resin panel P by a bending processing apparatus I is performed by a heating process wherein a bending upper mold 5 is allowed to fall toward a groove-shaped recessed part 2a from the position above the thermoplastic synthetic resin panel P arranged above a female mold 2 and the thermoplastic synthetic resin panel P is brought into contact with an elastic receiving mold 4 under pressure to be heated to a predetermined temp. and further performed by a series of operations containing a bending process for advancing the falling of the bending upper mold 5 to bend the thermoplastic synthetic resin panel P up to a predetermined angle α while pressing the panel P against the elasticity of the elastic receiving mold and a bending holding process for holding the bent angle of the panel P to the predetermined angle α.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and apparatus for bending a thermoplastic synthetic resin plate such as a polycarbonate resin plate.

[0002]

2. Description of the Related Art Conventionally, thermoplastic synthetic resin plates, such as polycarbonate resin plates, acrylic resin plates, ABS resin plates, and vinyl chloride resin plates, have been used as flat plates or by vacuum molding or air pressure molding. In addition to being used in a molded state, it is often used in a state formed by a bending method.

[0003] In particular, transparent polycarbonate resin plates and the like are often used as daylighting materials for roofs and walls of buildings, and are used as so-called corrugated sheets or folded plates whose sections are formed into a corrugated or square shape. ing. In this case, in the case of a bent product having a square shape, the bending axis direction is usually set as a length direction, and is formed in parallel and in a long length, for example, up to 12 m.
Because of the length of the molded product, mechanical properties such as impact strength at the bent portion are particularly important quality factors.

As a conventional means for forming this kind of bent-formed product, a thermoplastic synthetic resin plate is preheated to room temperature or a relatively low temperature, and then placed on a female rubber cushion material, and the male member is placed from above. A so-called cold-folding forming method of pressing and bending with a mold is often used. However, according to this method, a strong internal strain occurs in the entire bent portion of the molded product, and there is a problem that the mechanical strength inherent to the thermoplastic synthetic resin plate such as impact strength is reduced.

On the other hand, when the thickness of the thermoplastic synthetic resin plate is large, it is difficult to employ the cold bending method as described above. After the part is heated to the heat deformation temperature or higher, it is arranged in a female mold and pressed and bent by a male mold. As the heating means, a method is employed in which the thermoplastic synthetic resin plate is heated through an elongated slit by, for example, a gas combustion flame or an electric heater, or is brought into contact with an elongated metal surface heater to be heated.

However, according to such a method,
The curvature radius of the bent portion is small due to the heating means,
It is bent sharply, and the shape is constant in the bending axis direction,
At first glance it will be of high appearance quality,
On the other hand, as shown in FIG. 7, a thermoplastic synthetic resin plate (P
In the cross section of ′), local thermal deformation (F) has occurred, and as a result, a strong residual stress is generated in the portion, the impact resistance is low, and the mechanical strength of the thermoplastic synthetic resin plate is low. The property cannot be fully exhibited. In particular, in combination with the change in the environmental temperature due to seasonal factors, the temperature difference in the boundary area between the heated part and the non-heated part during heating increases, and residual stress is likely to be concentrated on the boundary area. There's a problem.

The present invention has been intensively studied in order to address the above-mentioned conventional problems, and as a result, when a thermoplastic synthetic resin plate is bent, as in the case of a conventional cold bending forming method, etc.
Using a known means of pressing and bending a thermoplastic synthetic resin plate against a cushion material made of a rubber-like elastic body, a heat transfer function is imparted by applying heat from the outside to the cushion material, and thermoplastic synthesis is performed. If means for bending from the inside while heating uniformly and wide in the length direction while heating the bent outer portion of the resin plate in contact with the heated cushion material is used, the residual generated in the bent portion is obtained. It has been found that stress can be dispersed, and the impact strength of the thermoplastic synthetic resin plate can be maintained without being significantly reduced.

[0008]

SUMMARY OF THE INVENTION Under the above-mentioned background, the present invention is to maintain a high and uniform impact resistance at a bent portion of a thermoplastic synthetic resin plate such as a polycarbonate resin plate. It is an object of the present invention to provide a method and apparatus for bending a thermoplastic synthetic resin plate.

[0009]

According to the above object, a first invention of the present invention is a female mold having a groove-shaped recess,
Heating heaters are buried in both side walls and / or the bottom wall of the groove-shaped concave portion, and the elastic receiving mold formed of a rubber-like body having a flat upper surface over the entire length in the groove-shaped concave portion, Using a female mold fitted in such an arrangement that the upper surface is located above the upper surface of the female mold, a thermoplastic synthetic resin plate is arranged on the female mold, and then from above the thermoplastic synthetic resin plate. After heating the thermoplastic synthetic resin plate to a predetermined temperature while pressing the thermoplastic synthetic resin plate against the elastic receiving mold by lowering the folding upper mold toward the groove-shaped concave portion, by further lowering the folding upper mold, A gist of the present invention is a method for bending a thermoplastic synthetic resin plate, wherein the thermoplastic synthetic resin plate is bent at a predetermined angle against the elasticity of the elastic receiving mold.

A second aspect of the present invention is a female mold having a groove-like concave portion, wherein both side walls of the groove-like concave portion and / or
Alternatively, a heater is extended in a buried state on the bottom wall portion, and an elastic receiving mold made of a rubber-like body having a flat upper surface extends over the entire length in the groove-shaped concave portion. A female mold fitted and inserted in a state where it is positioned, and a bending tool for descending from above toward the groove-shaped recess and pressing against the elasticity of the elastic receiving mold via a thermoplastic synthetic resin plate. The gist of the present invention is an apparatus for bending a thermoplastic synthetic resin plate comprising an upper mold.

As the thermoplastic synthetic resin plate to which the present invention is applied, besides a polycarbonate resin plate, an acrylic resin plate, an ABS resin plate, a vinyl chloride resin plate and the like can be applied. As a plate or the like, a resin substrate provided with a weather resistance imparting layer such as an acrylic resin film or a fluorine resin film, for example, is also applicable. A thickness of 1.0 mm to 10.0 mm is preferably used, but a thickness outside this range is also applicable.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof.

FIG. 1 is a cross-sectional view showing a first embodiment of a bending apparatus applied to the bending of a thermoplastic synthetic resin plate of the present invention. It is composed of a mold (2) and a folding upper mold (5).

The female mold (2) has a heater (3) buried in both side walls (2b) (2b) and a bottom wall (2c) of the groove-shaped recess (2a) so as to be buried. In the groove-shaped recess (2a), an elastic receiving die (4) made of a rubber-like body having a flat upper surface (f1) over the entire length is made of a band-shaped metal body between itself and the bottom wall (2c). Heat transfer plate (4a)
, The upper surface (f1) is connected to the upper surface (f) of the female mold (2).
2) It is inserted in a state of being positioned above. In this case, the upper surface (f1) of the elastic receiving mold (4) is arranged so as to be located usually about 2 to 5 mm above the upper surface (f2) of the female mold (2), and the plate (P) is in the female mold (2). Shall be set in a range that does not contact the upper surface of the.

Here, as the heater (3), a generally known heater, for example, a rod-shaped heater in which a nichrome wire is inserted into a ceramic tube or the like is applied.
Are both side walls (2b) and (2b) of the groove-shaped recess (2a).
And an extension groove (2d) provided in the bottom wall (2c)
(2e) is installed in a state of being connected in a buried state. In this case, the extension groove (2e) is released inside the groove-shaped recess (2a), but from above the heat-transfer plate (4a).
Is covered, whereby the heater (3e) and the elastic receiving die (4) are insulated. The heat capacity of the heater (3) can be arbitrarily set, but usually, the heat capacity of the heater (3e) is made larger than that of the heater (3d), so that the female mold (2) can be used.
It is desirable to enhance the heat distribution in the central part of the slab.

In the present invention, when the heater (3) is energized to generate heat, the resilient receiving mold (4) fitted in the groove-shaped recess (2a) receives heat from the heater (3) and the both side walls. Through the portions (2b) and (2b) and the heat transfer plate (4a), the heat is continuously received, the plate is placed in a heated state, and the thermoplastic synthetic resin plate (P) directly disposed thereon is heated and softened. Play the role of letting.

Further, as the material of the elastic receiving mold (4),
Synthetic rubber having heat resistance, such as fluorine rubber, silicone rubber, chlorosulfonated polyethylene, and the like,
The synthetic rubber having other heat resistance may be used as long as it can withstand repeated deformation.
In addition, as for the material, a material having good heat conductivity in addition to the above heat resistance and durability and having a rubber hardness of about 60 to 90 degrees is suitable.

Further, the external form of the elastic receiving mold (4) is not limited to an integral form, but may be divided into a plurality of upper and lower layers as shown in FIG. ,
They may be used in combination such that different materials are used. Also, the upper surface (f) of the elastic receiving mold (4)
The width (w) of 1) is set in a range suitable for the thickness (m) and the bending angle (α) of the thermoplastic synthetic resin plate (P) to be bent. For example, in order to bend a thermoplastic synthetic resin plate having a thickness of 10 mm at an angle of 90 degrees, the width (w) is desirably in the range of 30 to 50 mm.

The bending of the thermoplastic synthetic resin plate (P) by the bending apparatus (1) having such a structure is performed by the thermoplastic synthetic resin plate (P) placed on the female die (2). From above, the upper folding die (5) is lowered toward the groove-shaped concave portion (2a), and the thermoplastic synthetic resin plate (P) is pressed against the elastic receiving die (4) and is brought into a predetermined temperature. The heating and heating process is further performed, and the lowering of the folding upper mold (5) is further advanced, and the thermoplastic synthetic resin plate (P) is folded to a predetermined angle (α) while being pressed against the elasticity of the elastic receiving mold (4). This is performed by a series of operations including a bending step of bending and a bending and holding step of holding at a predetermined angle (α).

The heating conditions in the present invention are such that the temperature of the elastic receiving mold (4) is set in a temperature range from 50 ° C. to less than the heat deformation temperature of the thermoplastic synthetic resin plate (P). For example, when the thermoplastic synthetic resin plate (P) is a polycarbonate resin plate, the temperature is set in a temperature range from 70 ° C. to less than 135 ° C. Further, each time of the heating step, the bending step, and the bending holding step, the thermoplastic synthetic resin plate (P)
Set according to the thickness and type of For example, if the thickness is 1-5
mm, the heating step is performed for 7 to 15 seconds, the bending step is performed for 6 to 10 seconds, and the bending and holding step is performed for 6 to 10 seconds.

The heating conditions are set such that the thicker one has a longer time at a higher temperature and the thinner one has a shorter time at a lower temperature, depending on the thickness of the thermoplastic synthetic resin plate (P).
If the heating temperature is lower than 50 ° C., the residual stress at the time of bending increases, and if the temperature is higher than the thermal deformation temperature, unnecessary deformation of the thermoplastic synthetic resin plate (P) occurs.
It is desirable to set the temperature in a range from ℃ to a temperature lower by about 10 ℃ than the heat deformation temperature.

FIG. 2 is a sectional view of a bending apparatus showing a modification of the first embodiment.
And a folding upper die (15).

In the bending apparatus (11), a heater (13e) is mounted in an extension groove (12e) provided on the back side (12c) of the female die (12), and a groove-shaped recess is provided. The configuration is the same as that of the first embodiment shown in FIG. 1 except that only an elastic receiving mold (14) made of a rubber-like body having a flat upper surface (f1) is fitted over the entire length of (12a). Things. In this case, since a member equivalent to the heat transfer plate (4a) in FIG.
e) The efficiency of the heat transfer from (e) is high, and the maintenance of the device is easy.

FIG. 3 is a cross-sectional view of a bending apparatus according to a second embodiment, which comprises a bending apparatus (21) and a bending upper die (25).

In the bending apparatus (21), a heater (23) corresponding to the heater (3e) of the first embodiment is used.
The configuration is the same as that of the first embodiment except that only e) is extended and the heaters corresponding to the heaters (3d) and (3d) are omitted. In this case, as compared with the first embodiment, the overall heat capacity can be reduced and the temperature gradient at the center of the female mold (22) can be sharpened. Suitable for bending the resin plate (P).

FIG. 4 is a cross-sectional view of a bending apparatus according to a third embodiment, which comprises a bending apparatus (31) and an upper die for bending (35).

In the bending apparatus (31), heaters (33d) and (33d) corresponding to the heaters (3d) and (3d) of the first embodiment are extended, and the heater (3) is provided.
The heater corresponding to (e) is omitted, and the upper surface (f1) is provided over the entire length in a stepped groove-shaped concave portion (32a) having a retraction space (s) for deformation of an elastic receiving mold (34) at the bottom. ) Is an elastic receiving mold (3
The configuration is the same as that of the first embodiment shown in FIG. 1 except that only 4) is inserted. In this case, since the overall heat capacity can be made smaller and the temperature gradient at the center of the female mold (32) can be made gentler than in the first embodiment, the heat thickness can be relatively small. Suitable for bending plastic synthetic resin plate (P).

The bending apparatus of the present invention may have a configuration in which different elements of each embodiment are combined with each other, in addition to the above embodiments.

In the bending method of the present invention, assuming that the thermoplastic synthetic resin plate (P) is spring-backed, as shown in FIG.
To (δ) is smaller than the desired angle (θ), and when the cooling process is completed after the bending process, the pressing die set to the desired angle (θ) outside the bending apparatus is set. It is preferable to allow the cooling to be performed, and then to form a bend at the final desired angle (θ) while causing springback.

Next, as the female mold and the upper mold for bending in the bending apparatus of the present invention, metal molds are usually used. Then, both upper edges of the female groove-shaped recess are finished to have a curved surface with a radius of curvature of about 3 to 5 mm so that the polycarbonate resin plate can easily slide in the bending process. The tip of the mold has a radius of curvature of 2 to 1 in accordance with the desired radius of curvature of the bent portion.
It shall be finished in a curved shape of about 0 mm. The radius of curvature of the tip of the bending upper die is selected according to the thickness of the thermoplastic synthetic resin plate, but is preferably increased as long as the desired appearance of the bent portion is not impaired.

When the bending method and the processing apparatus of the present invention configured as described above are applied, the thermoplastic synthetic resin plate disposed on the female die of the processing apparatus is lowered by the lowering of the bending upper die. First, it is pressed against the upper surface of the elastic receiving die, and the outer portion of the predetermined bent portion is uniformly and widely heated in the length direction corresponding to the width of the elastic receiving die. Since the thermoplastic synthetic resin plate is subjected to the bending action while being pressed against the upper surface, the outer surface of the thermoplastic synthetic resin plate is in close contact with the elastic receiving mold, and is pressed by the elastic receiving mold to undergo elastic deformation in a uniform state. Is reliably supported by the surface of the elastic receiving die, and is subjected to the action of uniform bending deformation without local deformation unevenness.

Therefore, as shown in FIG. 6, the bent portion (V) of the thermoplastic synthetic resin plate (P) does not undergo local deformation and the residual stress is dispersed or not. Thus, the original impact resistance of the thermoplastic synthetic resin plate at the portion is maintained high. By appropriately selecting the heat capacity and the extension position of the heater, the temperature gradient at the boundary area (z) between the heated portion (Pm) and the non-heated portion (Pn) can be set to be gentle. Therefore, the above effect can be further enhanced, and the springback is reduced.

[0033]

EXAMPLES Examples of the present invention will be described below along with comparative examples.

Example 1 First, as a target thermoplastic synthetic resin plate (P), a polycarbonate resin having a total thickness of 5.0 mm, a width of 25 cm, and a length of 4 m provided with a weather resistance imparting layer made of an acrylic resin film. A board was prepared.

Next, in the bending apparatus having the structure shown in FIG. 1, an elastic receiving mold (4) having a width (w) of the upper surface (f1) of 30 mm is grooved through a heat transfer plate (4a). (2)
a) a female mold (2) fitted over the entire length thereof and a bending upper mold (5) having a tip with a radius of curvature of 10 mm.
A bending apparatus (1) having a mold length of 4.3 m was prepared.
In this case, the distance between the upper surface (f1) of the elastic receiving die (4) and the upper surface (f2) of the female die (2) was 4 mm. Then, a current is supplied to the heater (3) extending in the state of being positioned above and being buried in the side walls (2b) (2b) and the bottom wall (2c) of the groove-shaped recess, and the elastic receiver The mold (4) was heated such that the set temperature was 130 ° C. at the center and 80 ° C. at both ends.

Further, the polycarbonate resin plate is
In order to bend into a mountain-shaped cross-sectional shape as shown in FIG. 6, which has two bent portions with an expected angle of 130 degrees,
This was placed on the elastic receiving mold (4) along the length direction thereof, and heated for 9 seconds while being held by the bending upper mold (5). Next, the upper mold for folding (5) is lowered in 7 seconds until the predetermined angle (α) becomes 110 degrees, and is kept as it is for the next 7 seconds. 5) was raised and released. Then, the bent portion was allowed to cool, and the bending operation at one place was completed. The above operation was repeated twice to obtain the above-mentioned mountain-shaped bent body. The appearance quality was sufficient for practical use, although the radius of curvature of the bent portion was slightly larger than that of the conventional one.

In order to perform an impact resistance test on the above-obtained bent molded body, a test sample having a length of 50 mm was cut and sampled at five locations at equal intervals in the longitudinal direction. Then, after leaving all the samples for 1 hour in an environmental test chamber set at 10 ° C. below zero, a steel ball with a load of 21 kg was placed on the top of the sample by 3 m.
From the height of the specimen, and the state of destruction was observed. As a result, none of the samples was broken, and neither the whitening phenomenon nor the peeling phenomenon of the weather resistance imparting layer was observed.

Comparative Example 1 A polycarbonate resin plate similar to that used in Example 1 was prepared as a thermoplastic synthetic resin plate (P), and a mountain-shaped cross section similar to that of the example was obtained by a conventional cold bending method. The shape was bent.

The obtained sample had a sharper finish because the radius of curvature of the bent portion was smaller than that of the example.
When this sample was subjected to the same impact resistance test as in the examples, all five samples were broken at the bent portion, and the whitening phenomenon of the weather resistance imparting layer was observed near the broken portion.

Example 2 As a target thermoplastic synthetic resin plate (P), the same polycarbonate resin plate as in Example 1 except that the thickness was 2.0 mm was prepared.

Next, in the bending apparatus having the structure shown in FIG. 3, an elastic receiving mold (24) having a width (w) of the upper surface (f1) of 30 mm is grooved through a heat transfer plate (24a). Female mold (22) fitted over the entire length of the cylindrical recess (22a)
And a bending machine (21) having a mold length of 4.3 m, comprising a bending upper mold (25) having a tip with a radius of curvature of 4 mm.
And a heater (23) extending from the bottom wall (22c) of the groove-shaped recess is energized, and the elastic receiving mold (2) is supplied.
It heated so that the set temperature of the center part of 4) might be set to 120 degreeC.

Further, the polycarbonate resin plate is
In order to bend into a mountain-shaped cross-sectional shape having one bent portion at an intended angle of 90 degrees, this is arranged on an elastic receiving die (24) along the length direction thereof and folded. It was heated for 5 seconds while holding it with the upper mold for bending (25). Next,
The upper mold for bending (25) is lowered in 5 seconds until the predetermined angle (β) becomes 85 degrees, and the state is maintained for the next 5 seconds, and then the upper mold for bending (25) is removed. Ascended and released. Then, let the bent part cool down,
The folding operation has been completed. The appearance quality of the molded product was very uniform in the length direction without any local thermal deformation, although the radius of curvature of the bent portion was larger than that of the conventional product.

In order to carry out an impact resistance test on the above-obtained bent-formed body, a test sample having a length of 50 mm was cut and sampled at five places at equal intervals in the length direction. Then, after leaving all the samples for 1 hour in an environmental test room set at a temperature of 10 ° C. below zero, a steel ball with a load of 1 kg was dropped from the height of 3 m onto the top of the mountain shape of the sample, and the state of destruction was observed. did. As a result, none of the samples was broken, and neither the whitening phenomenon nor the peeling phenomenon of the weather resistance imparting layer was observed.

Comparative Example 2 As a thermoplastic synthetic resin plate (P), a polycarbonate resin plate similar to that used in Example 2 was prepared, and this was used.
13 mm by an electric heater through a long slit
It was heated to 0 ° C. and bent into the same mountain-shaped cross-sectional shape as in the example.

The obtained sample was finished with a smaller radius of curvature at the bent portion than in the example, but the boundary line between the bent portion and the flat portion remarkably meandered in the length direction.
When an impact resistance test was performed on this sample in the same manner as in the example, all five samples were broken at the bent portion, and a whitening phenomenon of the weather resistance imparting layer was observed near the broken portion.

Example 3 As a target thermoplastic synthetic resin plate (P), Example 2 was used.
A polycarbonate resin plate exactly the same as that described above was prepared.

Next, in the bending apparatus having the structure shown in FIG. 4, an elastic receiving mold (34) having an upper surface (f1) having a width (w) of 20 mm is fitted over the entire length in the groove-shaped concave portion (32a). A bending machine (31) having a mold length of 4.3 m, comprising an inserted female mold (32) and a bending upper mold (35) having a tip with a radius of curvature of 4 mm, is prepared. Electricity is supplied to the heater (33) extending from the bottom wall (32c) of the recess,
The set temperature at the center of the elastic receiving mold (34) is 120 ° C.
Was heated so that

In order to perform an impact resistance test on the above-obtained bent-formed body, a test sample having a length of 50 mm was cut and sampled at five locations at equal intervals in the length direction. Then, after leaving all the samples for 1 hour in an environmental test room set at a temperature of 10 ° C. below zero, a steel ball with a load of 1 kg was dropped from the height of 3 m onto the top of the mountain shape of the sample, and the state of destruction was observed. did. As a result, none of the samples was broken, and neither the whitening phenomenon nor the peeling phenomenon of the weather resistance imparting layer was observed.

[0049]

According to the present invention, as described above, a female mold having a groove-shaped recess is provided, and a heater is buried on both side walls and / or the bottom wall of the groove-shaped recess in a buried state. And a female mold in which an elastic receiving mold made of a rubber-like body having a flat upper surface is fitted over the entire length of the groove-shaped recess in such a state that the upper surface is located above the upper surface of the female mold. Using, a thermoplastic synthetic resin plate is arranged on the female mold, and then the upper mold for bending is lowered from above the thermoplastic synthetic resin plate toward the groove-shaped concave portion, thereby forming the thermoplastic synthetic resin plate. After heating to a predetermined temperature while being pressed against the elastic receiving mold, by further lowering the bending upper mold,
Since the thermoplastic synthetic resin plate is bent at a predetermined angle against the elasticity of the elastic receiving mold, the thermoplastic synthetic resin plate is uniform and wide in the length direction from the outer surface of the bent portion. Is heated, and then the outer surface is bent while being pressed against the upper surface of the elastic receiving die, and as a result, is reliably supported by the surface of the elastic receiving die that elastically deforms in a uniform state, Local deformation unevenness does not occur in the bent part, the residual stress is dispersed or less,
There is an effect that the original impact resistance of the thermoplastic synthetic resin plate in the portion is maintained high.

Further, since the bending apparatus according to the present invention uses a wide elastic receiving mold having a cushioning function as a heating source for heating the thermoplastic synthetic resin plate, a heating portion of the thermoplastic synthetic resin plate can be used. Since the boundary area between the heated part and the non-heated part can be accurately set and the temperature gradient can be set to be gentle, the above-mentioned effect can be further enhanced, and at the same time, a bent product with less springback can be obtained. There is.

Further, in the bending apparatus of the present invention, since a heat transfer plate can be interposed between the bottom of the female groove-shaped recess and the elastic receiving mold, the heat from the heater is elastically transferred. It can be evenly transmitted to the receiving mold, and the cushion effect can be changed by dividing the elastic receiving mold in the female groove recess into upper and lower layers and combining each rubber-like body with different materials and materials These effects can be further enhanced by implementing them in accordance with the material and thickness of the thermoplastic synthetic resin.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a bending apparatus according to the present invention.

FIG. 2 is a sectional view showing a modification of the first embodiment of the bending apparatus of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the bending apparatus according to the present invention.

FIG. 4 is a sectional view showing a third embodiment of the bending apparatus according to the present invention.

FIG. 5 is a cross-sectional view for explaining a relationship between a desired angle and a predetermined angle of bending of a thermoplastic synthetic resin plate.

FIG. 6 is a cross-sectional view for explaining a state of bending a thermoplastic synthetic resin plate.

FIG. 7 is a cross-sectional view for describing a state of bending processing of a conventional thermoplastic synthetic resin plate.

[Explanation of symbols]

 1-31 ... bending apparatus 2-32 ... female mold 2a-32a ... groove-shaped concave parts 3-33, 3d-33d ... heater 4-34 ... elastic receiving mold 4a ... heat transfer plate 5-35 ... bending Upper mold P: thermoplastic synthetic resin plate θ: desired angle

Claims (5)

[Claims] 1. A female mold having a groove-shaped recess, wherein a heater extends in a buried state on both side walls and / or a bottom wall of the groove-shaped recess, and a total length in the groove-shaped recess is provided. Over, an elastic receiving mold made of a rubber-like body having a flat upper surface is used with a female mold inserted in a state where the upper surface is located above the upper surface of the female mold, and a thermoplastic resin is placed on the female mold. A synthetic resin plate is disposed, and then the upper mold for bending is lowered from above the thermoplastic synthetic resin plate toward the groove-shaped concave portion, and the thermoplastic synthetic resin plate is heated to a predetermined temperature while being pressed against the elastic receiving die. After that, by further lowering the upper mold for bending, the thermoplastic synthetic resin plate is characterized in that the thermoplastic synthetic resin plate is bent at a predetermined angle against the elasticity of the elastic receiving die. Bending method. 2. The method for bending a thermoplastic synthetic resin plate according to claim 1, wherein the temperature of the elastic receiving die is set to a temperature in a range from 50 ° C. to a temperature lower than the thermal deformation temperature of the thermoplastic synthetic resin plate. 3. A female mold having a groove-shaped recess, wherein a heater is extended in a buried state on both side walls and / or a bottom wall of the groove-shaped recess, and a total length in the groove-shaped recess is provided. An elastic receiving mold made of a rubber-like body having a flat upper surface is fitted with a female mold inserted in an arrangement state such that the upper surface is located above the upper surface of the female mold, and from above toward the groove-shaped concave portion. An apparatus for bending a thermoplastic synthetic resin plate, comprising a bending upper die that descends and presses through the thermoplastic synthetic resin plate against the elasticity of the elastic receiving die. 4. The apparatus for bending a thermoplastic synthetic resin plate according to claim 3, wherein a heat transfer plate is interposed between the bottom of the female groove-shaped concave portion and the elastic receiving die. . 5. The apparatus for bending a thermoplastic synthetic resin plate according to claim 3, wherein the elastic receiving mold in the female groove-shaped concave portion has a plurality of layers vertically stacked.