Molding apparatus and molding method

The present invention relates to a molding apparatus and a molding method for molding a resin molded product.

As prior art documents by the applicant, for example, Patent Document 1 (WO2009 / 157197) discloses a molding apparatus for molding a resin molded product using a molten thermoplastic resin sheet.

As shown in FIG. 12, in the molding apparatus 100 of Patent Document 1, a mold 33 is slidably provided on the outer peripheral portion of the split mold 32, and the mold 33 is provided relative to the split mold 32. After moving, as shown in FIG. 13, the mold 33 is brought into contact with the side surface of the thermoplastic resin sheet P, and the thermoplastic resin sheet P, the mold 33, and the cavity 116 form a closed space. Next, as shown in FIG. 14, air in the closed space is sucked from the vacuum suction chamber 120 through the suction hole 122, the thermoplastic resin sheet P is attracted to the cavity 116, and the thermoplastic resin sheet P is sucked into the cavity 116. Shapes along the surface of. After that, the mold 33 and the split mold 32 are moved integrally, the split mold 32 is clamped, and the peripheral portions of the thermoplastic resin sheet P are welded to each other by the pinch-off portion 118 of the split mold 32. A parting line is formed on the joint surface of the two thermoplastic resin sheets P, and a closed hollow portion is formed inside the two thermoplastic resin sheets P. Next, the mold 33 and the split mold 32 are moved integrally, the split mold 32 is opened, the resin molded product is taken out, the burrs on the outer periphery are removed, and the resin molded product is molded. ..

The molding apparatus 100 of Patent Document 1 intermittently extrudes the thermoplastic resin from the extrusion slits provided in the T-die 28 at predetermined intervals at a predetermined extrusion amount per unit time, and the thermoplastic resin sheet in a molten state. The thermoplastic resin sheet P is extruded at a predetermined extrusion rate so that P hangs downward. Then, the thermoplastic resin sheet P extruded downward passes between the pair of rollers 30, and the distance between the pair of rollers 30 is narrowed to sandwich the thermoplastic resin sheet P, so that the pair of rollers 30 The thermoplastic resin sheet P is sent downward by rotation. At this time, while the thermoplastic resin sheet P is being fed to the pair of rollers 30, the delivery speed of the thermoplastic resin sheet P by the pair of rollers 30 is equal to or higher than the extrusion speed of the thermoplastic resin sheet P extruded from the extrusion slit. The rotation speed of the pair of rollers 30 is adjusted so as to be. As a result, the drawdown or neck-in of the thermoplastic resin sheet P is effectively prevented, and the thermoplastic resin sheet P having a uniform thickness in the extrusion direction is formed.

The drawdown is a phenomenon in which the molten sheet is stretched by the weight of the sheet with the passage of time, and the thickness becomes thinner toward the upper part of the sheet. Further, neck-in refers to a phenomenon in which the seat width is reduced due to shrinkage in the width direction of the seat due to drawdown.

<p><patcit num="1"><text>WO2009 / 157197</text></patcit></p>

<p num="0007"> In Patent Document 1, the rotation speed of the pair of rollers 30 is adjusted according to the extrusion speed of the thermoplastic resin sheet P extruded from the extrusion slit to prevent the plastic resin sheet P from drawing down or necking in. Therefore, in the invention of Patent Document 1, it is necessary to mount a pair of rollers 30. Therefore, it is necessary to develop a new mechanism capable of effectively preventing the drawdown or neck-in of the thermoplastic resin sheet P without using a pair of rollers 30.</p><p num="0008"> The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a molding apparatus and a molding method capable of suppressing drawdown of a thermoplastic resin extruded into a sheet from an extruder.</p>

<p num="0009"> In order to achieve such an object, the present invention has the following features.</p><p num="0010"> &lt;Molding equipment&gt; The molding apparatus according to the present invention is A molding device that vacuum-sucks a thermoplastic resin extruded into a sheet from an extruder into a cavity of a mold and shapes the thermoplastic resin into a shape along the cavity. A mold that is located around the mold and is movable with respect to the mold is provided. The formwork is movable with respect to the first formwork including at least a first formwork including at least a lower part of the formwork forming the lower side of the formwork and an upper part of the formwork forming the upper part of the formwork. It is characterized by having a second formwork.</p><p num="0011"> &lt;Molding method&gt; The molding method according to the present invention is A mold that is located around the mold and is movable with respect to the mold is brought into contact with the thermoplastic resin extruded into a sheet from the extruder, and the thermoplastic resin moves downward while contacting the mold. A mold driving process that moves the mold so that it hangs down, A shaping step of vacuum-sucking the thermoplastic resin facing the cavity of the mold into the cavity and shaping the thermoplastic resin into a shape along the cavity. It is characterized by having.</p><p num="0012"> The molding method according to the present invention is A mold driving step in which a mold is brought into contact with a thermoplastic resin extruded into a sheet from an extruder, and the mold is moved so as to hang downward while the thermoplastic resin is in contact with the mold. A shaping step of vacuum-sucking the thermoplastic resin facing the cavity of the mold into the cavity and shaping the thermoplastic resin into a shape along the cavity. It is characterized by having.</p>

<p num="0013"> According to the present invention, it is possible to suppress the drawdown of the thermoplastic resin extruded into a sheet from the extruder.</p>

<figref num="1">It is a figure which shows the structural example of the molding apparatus 1 of this embodiment.</figref><figref num="2">It is a figure which shows the structural example of the split mold 32 and the mold 33 of this embodiment.</figref><figref num="3">It is the first figure which shows the structural example of the suction part 34.</figref><figref num="4">It is the 2nd figure which shows the structural example of the suction part 34.</figref><figref num="5">It is a figure which shows the state which the 2nd mold 200 was in contact with the thermoplastic resin sheet P extruded from the T die 28 in the molding apparatus 1 shown in FIG.</figref><figref num="6">FIG. 5 is a diagram showing a state in which the first mold 201 is in contact with the thermoplastic resin sheet P from the aspect shown in FIG.</figref><figref num="7">It is a figure which shows the state which vacuum-sucked the thermoplastic resin sheet P into the cavity 116 of the split die 32 from the aspect shown in FIG.</figref><figref num="8">It is a figure which shows the state which the split die 32 was molded from the aspect shown in FIG.</figref><figref num="9">It is a figure which shows the state which opened the split mold 32 from the aspect shown in FIG.</figref><figref num="10">It is a figure which shows the structural example of the molding apparatus 1 of the 2nd Embodiment.</figref><figref num="11">It is a figure which shows the structural example of the molding apparatus 1 of the 3rd Embodiment.</figref><figref num="12">It is a figure which shows the structural example of the molding apparatus 100 which is related to this invention.</figref><figref num="13">It is the first figure which shows the molding method example of the molding apparatus 100 which is related to this invention.</figref><figref num="14">It is a 2nd figure which shows the molding method example of the molding apparatus 100 which is related to this invention.</figref>

&lt;Outline of the molding apparatus 1 of this embodiment&gt; First, the outline of the molding apparatus 1 of the present embodiment will be described with reference to FIGS. 1 and 10.

The molding apparatus 1 of the present embodiment is located around the mold 32 with respect to the extruder 12 that extrudes the melt-kneaded thermoplastic resin P into a sheet shape and the thermoplastic resin P extruded from the extruder 12 into a sheet shape. The movable mold 33 is brought into contact with the mold 32, and the mold 33 is moved so that the thermoplastic resin P hangs down while contacting the mold 33, and the cavity of the mold 32 is also contacted. A mold clamping device 10 that vacuum-sucks the thermoplastic resin P facing the 116 into the cavity 116, shapes the thermoplastic resin P into a shape along the cavity 116, molds the mold 32, and molds the resin molded product. It is a molding apparatus 1 having.

The mold 33 of the molding apparatus 1 of the present embodiment is movable with respect to the mold 32, and includes a first mold 201 including at least a frame lower portion 33-2 constituting the lower side of the mold 33, and a mold. It has a second formwork 200, which includes at least the upper part 33-1 of the frame forming the upper side of the frame 33 and is movable with respect to the first formwork 201.

By having the above configuration, the molding apparatus 1 of the present embodiment is located around the mold 32 and can be moved to the mold 32 with respect to the thermoplastic resin P extruded from the extruder 12 into a sheet shape. The mold 33 can be brought into contact with the mold 33 so that the thermoplastic resin P hangs downward while contacting the mold 33. As a result, the thermoplastic resin P hangs downward while being in contact with the mold 33, so that friction is generated between the thermoplastic resin P and the mold 33. Therefore, the weight of the thermoplastic resin P is reduced by friction, and the drawdown of the thermoplastic resin P can be suppressed.

In FIG. 1, the thermoplastic resin P extruded from the extruder 12 into a sheet shape is brought into contact with the mold 33, which is located around the mold 32 and is movable with respect to the mold 32, to be thermoplastic. The resin P hangs down while contacting the mold 33. However, as shown in FIG. 10, the mold 32 is brought into contact with the thermoplastic resin P extruded in the form of a sheet from the extruder 12, and the thermoplastic resin P hangs down while being in contact with the mold 32. It is also possible to do. In this case as well, since friction is generated between the thermoplastic resin P and the mold 32, the weight of the thermoplastic resin P is reduced by the friction, and the drawdown of the thermoplastic resin P can be suppressed. Hereinafter, the molding apparatus 1 of the present embodiment will be described in detail with reference to the attached drawings.

&lt;Structure example of molding device 1&gt; First, a configuration example of the molding apparatus 1 of the present embodiment will be described with reference to FIG.

The molding device 1 of the present embodiment is a device for molding a resin molded product, and is configured to include an extrusion device 12 and a mold clamping device 10, and is a thermoplastic resin sheet in a molten state from the extrusion device 12. P is extruded into the mold clamping device 10, and the thermoplastic resin sheet P is mold-clamped by the mold clamping device 10 to mold the resin molded product.

The extrusion device 12 includes a cylinder 18 to which a hopper 16 is attached, a screw (not shown) provided in the cylinder 18, a hydraulic motor 20 connected to the screw, an accumulator 22 communicating with the cylinder 18, and an accumulator. It is composed of a plunger 24 that communicates with 22 and a T-die 28.

In the extruder 12 of the present embodiment, the resin pellets charged from the hopper 16 are melted and kneaded by the rotation of the screw by the hydraulic motor 20 in the cylinder 18 to form a molten resin (molten resin). Next, the molten resin is transferred to the accumulator 22 and stored in a certain amount, and the molten resin is sent toward the T die 28 by the drive of the plunger 24, and a continuous sheet is sent from the extrusion slit (not shown) of the T die 28. Extrude the shaped thermoplastic resin sheet P. The thermoplastic resin sheet P extruded from the extrusion slit of the T-die 28 is hung between the split molds 32. As a result, the thermoplastic resin sheet P is arranged between the split dies 32 in a state where the thermoplastic resin sheet P has a uniform thickness in the vertical direction (extrusion direction).

The extrusion capacity of the extruder 12 is appropriately selected from the viewpoints of the size of the resin molded product to be molded, the drawdown of the thermoplastic resin sheet P, or the prevention of neck-in occurrence. Specifically, from a practical point of view, the extrusion amount of one shot in intermittent extrusion is preferably 1 to 10 kg, and the extrusion speed of the thermoplastic resin sheet P from the extrusion slit is several hundred kg / hour or more. More preferably, it is 700 kg / hour or more. Further, from the viewpoint of preventing the drawdown or neck-in of the thermoplastic resin sheet P, the extrusion of the thermoplastic resin sheet P is preferably as short as possible, and depends on the resin type, MFR value, and MT value, but is generally used. In addition, extrusion is preferably completed within 40 seconds, more preferably within 10-20 seconds.

Therefore, the unit area (1 cm) from the extrusion slit of the thermoplastic resin.²), Extrusion amount per unit time (h) is 50 kg / h cm²Above, more preferably 150 kg / h cm²That is all. For example, from an extruded slit of T-die 28 with a slit spacing of 0.5 mm and a slit length of 1000 mm in the width direction, a density of 0.9 g / cm.³When extruding a thermoplastic resin sheet P with a thickness of 1.0 mm, a width of 1000 mm, and a length of 2000 mm in the extrusion direction in 15 seconds, 1.8 kg of thermoplastic resin is extruded in 15 seconds per shot. Therefore, the extrusion speed is 432 kg / hour, and the extrusion speed per unit area is about 86 kg / h cm.²Can be calculated.

The extrusion slit provided in the T-die 28 is arranged vertically downward, and the thermoplastic resin sheet P extruded from the extrusion slit is fed vertically downward in the form of hanging from the extrusion slit as it is. .. The thickness of the thermoplastic resin sheet P of the extruded slit can be changed by changing the slit spacing.

However, the thermoplastic resin sheet P extruded from the T die 28 can be adjusted so that the thickness in the extrusion direction becomes uniform in a state of being hung between the split dies 32, that is, at the time of molding. preferable. In this case, the slit interval can be gradually widened from the start of extrusion and varied so as to be maximum at the end of extrusion. As a result, the thickness of the thermoplastic resin sheet P extruded from the T die 28 gradually increases from the start of extrusion, but the thermoplastic resin sheet P extruded in the molten state is stretched by its own weight and is stretched from below to above the sheet. Since it gradually becomes thinner, the portion that is pushed out thickly by widening the slit interval and the portion that is stretched and thinned by the draw-down phenomenon cancel each other out, and the thickness can be adjusted to be uniform from the upper side to the lower side of the sheet.

The mold clamping device 10 of the present embodiment is a mold for moving the split mold 32 and the split mold 32 between the open position and the closed position in a direction substantially orthogonal to the supply direction of the thermoplastic resin sheet P. It is configured to include a drive device (not shown).

The split molds 32 are arranged so that the cavities 116 face each other, and the cavities 116 are arranged so as to face substantially the vertical direction. The surface of the cavity 116 is provided with uneven portions according to the outer shape and surface shape of the resin molded product molded based on the molten thermoplastic resin sheet P. Further, as shown in FIG. 2A, a pinch-off portion 118 is formed around the cavity 116 of the split mold 32. 2 (a) to 2 (d) show a configuration example of one of the split molds 32A and the mold 33A. The configuration example of the other split mold 32B and the mold 33B is also configured in almost the same manner.

The pinch-off portion 118 is formed in an annular shape around the cavity 116 and projects toward the opposing split mold 32. As a result, when the split mold 32 is molded, the tips of the pinch-off portions 118 come into contact with each other, and a parting line PL can be formed on the peripheral edge of the resin molded product.

Further, a mold 33 is provided on the outer peripheral portion of the split mold 32, and the mold 33 is made movable relative to the split mold 32 by a mold drive device (not shown). More specifically, one mold 33A projects toward the split mold 32B so that it can come into contact with the thermoplastic resin sheet P arranged between the split molds 32, and the other mold. The frame 33B projects toward the split mold 32A so that it can come into contact with the thermoplastic resin sheet P arranged between the split molds 32. It is preferable that the distance between the split mold 32 and the mold 33 is such that the movement of the mold 33 is not hindered and that there is as little gap as possible. The distance between the split mold 32 and the mold 33 is preferably less than 1 mm, more preferably less than 0.5 mm.

In the formwork 33 of the present embodiment, as shown in FIGS. 2A to 2D, the central portion 33A-2'' of the frame lower part 33A-2 constituting the lower side of the formwork 33A starts from the formwork 33A. As shown in FIGS. 2 (b) to 2 (d), only the central portion 33A-2'' of the lower frame 33A-2 can be moved independently of the formwork 33A.

Therefore, as shown in FIGS. 2A to 2D, the mold 33 of the present embodiment is a first mold composed of the mold 33A of the central portion 33A-2'' of the frame lower portion 33A-2. The first formwork 201A is moved so that the frame 201A and the second formwork 200A composed of the formwork 33A other than the first formwork 201A are moved independently. It includes a formwork drive device (not shown) and a second formwork drive device (not shown) for moving the second formwork 200A. The formwork drive device is preferably driven hydraulically. By performing the hydraulic system, it is possible to easily control the movement of the respective molds 200A and 201A. It is preferable that each formwork drive device is arranged in the central portion constituting each formwork 200A, 201A. Since the central portion constituting each formwork 200A, 201A is not easily affected by thermal expansion, by arranging the formwork drive device in the central portion which is not easily affected by the thermal expansion, each formwork 200A, Even if the 201A expands thermally, the respective molds 200A and 201A can be moved stably.

As shown in FIGS. 2 (b) to 2 (d), the mold 33 of the present embodiment is provided so as to surround the split mold 32A with a square, and the first mold 201A is a square. The lower side is formed, and the second formwork 200 is integrally formed with the upper side and the left and right sides of the square, and the first formwork 201A and the second formwork 200A are separated and moved. First, as shown in FIG. 2C, the second formwork 200A is moved by the second formwork drive device (not shown), and the second formwork 200A is made of a thermoplastic resin. After abutting on the sheet P (not shown), as shown in FIG. 2 (d), the first formwork 201A is moved by the first formwork drive device (not shown), and the first formwork 201A is moved. The mold 201A can be brought into contact with the thermoplastic resin sheet P (not shown). As a result, while hanging the thermoplastic resin sheet P along the left and right sides of the second mold 200A, the thermoplastic resin sheet P is prevented from riding on the first mold 201A, and the lower part of the frame 33A-2. It is possible to prevent the formation of a resin pool at the uppermost end of the central portion 33A-2''. Further, since the thermoplastic resin sheet P can be hung down along the U-shaped portion (second mold 200A), the thermoplastic resin sheet P tends to be a resistance to hang down, and drawdown can be suppressed. ..

For example, when the thermoplastic resin sheet P hangs down along the mold 33A, a part of the resin of the thermoplastic resin sheet P is removed from the uppermost end of the central portion 33A-2'' of the lower frame 33A-2 to the mold 33A. There is a risk that it will flow out to the inside of the frame and a resin pool will form at the uppermost end of the central part 33A-2'' of the lower part 33A-2 of the frame. Therefore, as shown in FIGS. 2 (c) and 2 (d), the molding apparatus 1 of the present embodiment moves only the second mold 200A and brings it into contact with the thermoplastic resin sheet P to bring it into contact with the thermoplastic resin sheet P. After the sheet P has passed the position of the lower frame 33A-2, the first mold 201A is moved and brought into contact with the thermoplastic resin sheet P, and a part of the resin of the thermoplastic resin sheet P is removed from the lower frame 33A-. It is prevented from flowing out to the inside of the formwork 33A from the uppermost end of the central part 33A-2'' of 2. As a result, the thermoplastic resin sheet P is hung along the left and right sides of the second mold 200A, and the thermoplastic resin sheet P is prevented from riding on the first mold 201A, so that the lower part of the frame 33A-2 It is possible to prevent the formation of a resin pool at the uppermost end of the central portion 33A-2''. Further, since the thermoplastic resin sheet P can be hung down along the U-shaped portion (second mold 200A), the thermoplastic resin sheet P tends to be a resistance to hang down, and drawdown can be suppressed. ..

Further, as shown in FIG. 2A, the mold 33A is configured to have a suction portion 34 on the contact surface 100 that comes into contact with the thermoplastic resin sheet P. The suction unit 34 sucks air, and the thermoplastic resin sheet P is sucked into the mold 33A by the suction of the suction unit 34, and the thermoplastic resin sheet P is brought into close contact with the mold 33A. The suction portion 34 can be formed in various shapes (for example, a circular shape, an elliptical shape, a polygonal shape, etc.), but is formed in a groove shape (linear shape) as shown in FIG. 2 (a). It is preferable to do so. For example, when the suction portion 34 is made into a hole shape (dot shape), the thermoplastic resin sheet P is partially adsorbed on the contact surface 100, and the thermoplastic resin in the portion not attracted by the suction portion 34. The sheet P may float from the contact surface 100. Therefore, by forming the suction portion 34 in a groove shape (linear shape), the thermoplastic resin sheet P can be attracted to the contact surface 100 in a groove shape, so that the portion not attracted by the suction portion 34 can be attracted. The thermoplastic resin sheet P can be made difficult to float from the contact surface 100.

&lt;Structure example of suction unit 34&gt; Next, a configuration example of the suction unit 34 will be described with reference to FIGS. 3 and 4. FIG. 3 (a) shows an example of the upper surface configuration of the suction unit 34, and FIGS. 3 (b) and 3 (c) show an example of the cross-sectional configuration of the suction unit 34. FIG. 4 shows a configuration example of the lid member 344 constituting the suction unit 34.

As shown in FIG. 3A, the suction portion 34 of the present embodiment is provided on the contact surface 100 of the mold 33, and as shown in FIG. 3B, the suction portion 34 is provided inward from the contact surface 100. A recessed first recess 341, a second recess 342 recessed further inward from the bottom surface of the first recess 341, and a hole 343 formed by opening a part of the bottom surface of the second recess 342. It is configured to have a lid member 344 arranged in the first recess 341.

The lid member 344 is configured in the shape shown in FIG. 4, and the lid member 344 is fitted into the first recess 341 and fastened on the bottom surface of the second recess 342 by a joining member 345 such as a screw. As shown in FIG. 4, the lid member 344 of the present embodiment has a recess 346 that is recessed inward only in a portion corresponding to the hole 343. FIG. 3 (b) shows an example of the cross-sectional configuration of the suction portion 34 at the position where the recess 346 is provided (position of A1-A2), and FIG. 3 (c) shows the position where the recess 346 is not provided (B1-B1-). An example of the cross-sectional configuration of the suction portion 34 (position of B2) is shown. As shown in FIG. 3B, a space is formed between the bottom surface of the first recess 341 and the lid member 344 at the position where the recess 346 is provided. On the other hand, as shown in FIG. 3C, in the position where the recess 346 is not provided, no space is formed between the bottom surface of the first recess 341 and the lid member 344, and the first recess 341 is not provided. The bottom surface of the lid member 344 is in contact with the bottom surface.

As shown in FIG. 3B, the suction portion 34 of the present embodiment has a groove-shaped gap 101 between the side wall of the first recess 341 and the side wall of the lid member 344 (see FIG. 3A). ), And the gap 101 and the hole 343 communicate with each other in the space formed by the recess 346. Further, the hole 343 communicates with the suction path 347 which can be depressurized. Therefore, the air of the contact surface 100 can be sucked through the space formed by the suction path 347, the hole 343, and the recess 346, and the gap 101, and the thermoplastic resin sheet P can be sucked into the contact surface 100.

In the suction portion 34 of the present embodiment, when the thermoplastic resin sheet P is sucked into the contact surface 100, the thermoplastic resin sheet P is made to bite into the gap 101, so that the width of the gap 101 is 0.3 mm or more. It is preferably 0.5 mm or more, and more preferably 0.5 mm or more. As a result, the thermoplastic resin sheet P can be made to bite into the gap 101, and the thermoplastic resin sheet P can be brought into close contact with the contact surface 100.

Further, as shown in FIG. 3A, the suction portion 34 of the present embodiment is configured to have groove-shaped gaps 101 at both ends of the lid member 344. However, it is also possible to have a groove-shaped gap 101 at one end of the lid member 344. That is, the suction unit 34 of the present embodiment can be configured by arranging a plurality of rows of groove-shaped gaps 101, or by arranging only one row. However, it is preferable that the suction unit 34 is configured by arranging a plurality of rows of groove-shaped gaps 101. As a result, the thermoplastic resin sheet P can be easily brought into close contact with the contact surface 100.

The split mold 32 of the present embodiment is driven by a mold drive device (not shown), and in the open position, the molten thermoplastic resin sheet P can be arranged between the split molds 32. Further, in the closed position, the pinch-off portions 118 of the split mold 32 are in contact with each other to form a closed space in the split mold 32. Regarding the movement of each divided mold 32 from the open position to the closed position, the closed position is the position of the center line of the thermoplastic resin sheet P in the molten state, and each divided mold 32 is driven by the mold driving device. I try to move toward that position.

The thermoplastic resin sheet P is formed of polypropylene, polyolefin resin, or the like. For the thermoplastic resin sheet P of the present embodiment, it is preferable to use a resin material having a high melt tension from the viewpoint of preventing variations in wall thickness due to drawdown, neck-in, etc. It is preferable to use a resin material having high fluidity in order to improve the transferability and followability of the resin material.

Specifically, it is a polyolefin (for example, polypropylene, high-density polyethylene) which is a homopolymer or copolymer of olefins such as ethylene, propylene, butene, isoprene pentene, and methylpentene, and is MFR (JIS) at 230 ° C. According to K-7210, a test temperature of 230 ° C and a test load of 2.16 kg) of 3.5 g / 10 minutes or less can be applied. When the MFR is larger than 3.5 g / 10 minutes, the drawdown becomes severe and it becomes difficult to mold a thin-walled molded product.

Further, when molding a resin molded product having a complicated shape having an average wall thickness of 2 mm or less and a bent portion bent at an angle (60 degrees or more) of a predetermined value or more, silica, mica, talc, and carbon dioxide are used. It is preferable to add a powdery inorganic filler such as calcium or a fibrous inorganic filler such as glass fiber or carbon fiber. As a result, the average wall thickness can be reduced, and a resin molded product having a complicated shape can be molded. When the amount of the inorganic filler added is large, the surface of the molded product is roughened and pinholes are likely to occur. Therefore, it is preferable to add the inorganic filler in an amount of less than 30% by weight in order to suppress the roughness of the surface of the molded product and to make it difficult for pinholes to occur.

When molding a resin molded product, it is preferable to apply a powdery filler rather than a fibrous filler. This is because the fibrous filler is difficult to suppress wrinkles in the direction orthogonal to the extrusion direction because the fibers are oriented in the extrusion direction. Further, among the powdery fillers, it is more preferable to apply talc. This is because talc has good dispersibility in the resin.

Further, in order to prevent cracking due to impact, it is also possible to add the hydrogenated styrene-based thermoplastic elastomer in the range of less than 30 wt%, preferably less than 15 wt%. As the hydrogenated styrene-based thermoplastic elastomer, a styrene-ethylene / butylene-styrene block copolymer, a styrene-ethylene / propylene-styrene block copolymer, a hydrogenated styrene-butadiene rubber, and a mixture thereof can be applied.

It is also possible to add plasticizers, stabilizers, colorants, antistatic agents, flame retardants, foaming agents and the like.

&lt;Example of molding process of molding device 1&gt; Next, an example of a molding process of a resin molded product using the molding apparatus 1 of the present embodiment will be described with reference to FIGS. 1, 5 to 9.

First, as shown in FIG. 1, the thermoplastic resin sheet P is extruded from the T die 28, and the extruded thermoplastic resin sheet P is hung between the pair of split dies 32.

After the thermoplastic resin sheet P has passed the position of the frame upper portion 33-1 of the mold 33, as shown in FIG. 5, the second mold 200 located around the split mold 32 is subjected to the thermoplastic resin sheet. The second mold 200 is brought into contact with the thermoplastic resin sheet P by moving it forward toward P. As a result, the thermoplastic resin sheet P hangs downward along the side surface shape of the second mold 200.

In this case, since the thermoplastic resin sheet P hangs downward along the contact surface 100 of the second mold 200, friction occurs between the thermoplastic resin sheet P and the contact surface 100. Therefore, the weight of the thermoplastic resin sheet P is reduced by friction, and the drawdown of the thermoplastic resin sheet P can be suppressed.

After the second mold 200 is brought into contact with the thermoplastic resin sheet P, the second mold 200 is moved forward by a predetermined distance in order to push the thermoplastic resin sheet P with the second mold 200. It is preferable to move it. As a result, the thermoplastic resin sheet P can be hung downward along the side surface shape of the second mold 200 while pushing the thermoplastic resin sheet P with the second mold 200.

After the thermoplastic resin sheet P has passed the position of the frame lower portion 33-2 of the mold 33, as shown in FIG. 6, the first mold 201 is moved forward toward the thermoplastic resin sheet P. The first mold 201 is brought into contact with the thermoplastic resin sheet P. As a result, the thermoplastic resin sheet P can be brought into contact with the contact surface 100 on the entire circumference of the mold 33. As shown in FIG. 6, the first mold 201 has a cavity 116 at the rear end of the first mold 201 when the first mold 201 is brought into contact with the thermoplastic resin sheet P. The first mold 201 and the split mold 32 are overlapped with each other in the vertical direction so as not to be located in front of the mold 201. As a result, it is possible to prevent a gap from being formed between the first mold 201 and the split mold 32.

After the thermoplastic resin sheet P is brought into contact with the contact surface 100 around the entire circumference of the mold 33, air is sucked from the suction portion 34 provided on the contact surface 100, and the thermoplastic resin sheet P is sucked into the suction portion 34. To suck. As a result, the thermoplastic resin sheet P can be brought into close contact with the contact surface 100. As a result, a closed space can be formed by the thermoplastic resin sheet P, the mold 33, and the cavity 116.

After the thermoplastic resin sheet P is brought into close contact with the contact surface 100 by the suction portion 34 to form a closed space, the mold 33 is moved rearward and the thermoplastic resin sheet P is hit against the pinch-off portions 118-1, 118-2. As shown in FIG. 7, the air in the closed space is sucked from the vacuum suction chamber 120 through the suction hole 122, the thermoplastic resin sheet P is attracted to the cavity 116, and the thermoplastic resin sheet P is sucked into the cavity 116. Shapes along the surface of. When sucking the air in the closed space, it is preferable that the thermoplastic resin sheet P is inflated toward the cavity 116 and the thermoplastic resin sheet P is shaped along the surface of the cavity 116. As a result, the thermoplastic resin sheet P can be efficiently shaped into a shape along the surface of the cavity 116.

Next, the mold 33 and the split mold 32 are moved forward, the split molds 32 are configured to be close to each other as shown in FIG. 8, the split mold 32 is molded, and the split mold 32 is formed. The peripheral portions of the thermoplastic resin sheet P are welded to each other by the pinch-off portion 118 of the above. As a result, a parting line PL is formed on the joint surface of the two thermoplastic resin sheets P, and a closed hollow portion 151 is formed inside the two thermoplastic resin sheets P.

Next, as shown in FIG. 9, the split dies 32 are moved away from each other, the split dies 32 are opened, the resin molded product is taken out, and burrs on the outer peripheral portion are removed. Thereby, the resin molded product can be molded.

&lt;Action / effect of molding apparatus 1 of this embodiment&gt; As described above, the forming device 1 of the present embodiment is located around the dividing die 32 with respect to the thermoplastic resin sheet P extruded from the extrusion device 12, and is movable with respect to the dividing die 32. The 33 is brought into contact with the mold 33, and the mold 33 is moved so that the thermoplastic resin sheet P hangs down while being in contact with the mold 33. As a result, the thermoplastic resin sheet P extruded from the extruder 12 hangs down while contacting the mold 33, so that friction is generated between the thermoplastic resin sheet P and the mold 33. As a result, the weight of the thermoplastic resin sheet P is reduced by friction, and the drawdown of the thermoplastic resin sheet P can be suppressed.

Further, the formwork 33 of the present embodiment includes a first formwork 201 including at least a frame lower part 33-2 constituting the lower side of the formwork 33, and a frame upper part 33-1 forming the upper side of the formwork 33. It has at least a second formwork 200 that is movable with respect to the first formwork 201 including the second formwork 200, and the second formwork 200 is moved closer to the thermoplastic resin sheet P side than the first formwork 201. When the thermoplastic resin sheet P is hung downward while being in contact with the second mold 200, and the lower end of the thermoplastic resin sheet P reaches below the second mold 200, the first The mold 201 is moved to the thermoplastic resin sheet P side and brought into contact with the thermoplastic resin sheet P. As a result, it is possible to prevent a resin pool from being generated at the uppermost end of the central portion 33-2'' of the frame lower portion 33-2.

(Second Embodiment) Next, the second embodiment will be described.

In the first embodiment, as shown in FIG. 1, the thermoplastic resin sheet P extruded from the extruder 12 is located around the dividing die 32 and is movable with respect to the dividing die 32. The frame 33 was brought into contact with the thermoplastic resin sheet P so as to hang downward while being in contact with the mold 33.

In the second embodiment, as shown in FIG. 10, the split die 32 is brought into contact with the thermoplastic resin sheet P extruded from the extruder 12, and the thermoplastic resin sheet P is in contact with the split die 32. Try to hang down. In this case as well, friction is generated between the thermoplastic resin sheet P and the split mold 32, so that the weight of the thermoplastic resin sheet P is reduced by the friction, and the drawdown of the thermoplastic resin sheet P is suppressed. Can be done. Therefore, as shown in FIG. 10, even in the molding apparatus 1 without the mold 33, the split mold 32 is brought into contact with the thermoplastic resin sheet P in the same manner as the mold 33 of the first embodiment. Since the thermoplastic resin sheet P hangs down while being in contact with the split mold 32, the drawdown of the thermoplastic resin sheet P can be suppressed.

The timing for bringing the split mold 32 into contact with the thermoplastic resin sheet P is the mold drive device (not shown) when the thermoplastic resin sheet P extruded from the extruder 12 passes through the upper end of the split mold 32. ) Moves the split mold 32 so that the split mold 32 is brought into contact with the thermoplastic resin sheet P. As a result, it is possible to prevent a resin pool from being generated at the uppermost end of the split mold 32.

Further, after the split die 32 is brought into contact with the thermoplastic resin sheet P, it is preferable to move the split die 32 forward by a predetermined distance in order to push the thermoplastic resin sheet P with the split die 32. As a result, the thermoplastic resin sheet P can be hung downward along the side surface shape of the split mold 32 while pushing the thermoplastic resin sheet P with the split mold 32.

As shown in FIG. 10, in the case of the molding apparatus 1 without the mold 33, the split mold 32 is brought into contact with the thermoplastic resin sheet P extruded from the extruder 12, and the thermoplastic resin sheet P is the split mold. Move the split mold 32 so that it hangs down while touching the 32. Next, the thermoplastic resin sheet P facing the cavity 116 of the split mold 32 is vacuum-sucked into the cavity 116, the thermoplastic resin sheet P is shaped into a shape along the cavity 116, and the split mold 32 is molded. Then, the resin molded product will be molded.

(Third Embodiment) Next, a third embodiment will be described.

In the first embodiment, as shown in FIG. 1, the upper frame 33-1 forming the upper side of the mold 33 and the lower frame 33-2 forming the lower side of the mold 33 are located on the same vertical line. The mold 33 was brought into contact with the thermoplastic resin sheet P extruded from the extruder 12, and the thermoplastic resin sheet P hung downward while being in contact with the mold 33.

In the third embodiment, as shown in FIG. 11, the frame lower portion 33-2 constituting the lower side of the mold 33 is a thermoplastic resin sheet P more than the frame upper portion 33-1 constituting the upper side of the mold 33. The thermoplastic resin sheet P protruding to the side and extruded from the extruder 12 abuts between the frame upper part 33-1 and the frame lower part 33-2, and the corresponding thermoplastic resin sheet P is on the side surface of the mold 33. It should hang down along the shape 100.

As a result, the thermoplastic resin sheet P hangs downward along the side surface shape 100 of the mold 33, so that friction is generated between the thermoplastic resin sheet P and the mold 33. As a result, the weight of the thermoplastic resin sheet P is reduced by friction, and the drawdown of the thermoplastic resin sheet P can be suppressed.

As in the first embodiment, the formwork 33 of the third embodiment is also configured so that the first formwork 201 and the second formwork 200 are moved independently of each other, and the lower part 33A of the frame is formed. We will prevent the formation of resin pools at the uppermost end of the central part 33A-2'' of -2.

It should be noted that the above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment, and various modifications are made without departing from the gist of the present invention. It is possible to carry out in.

P Thermoplastic resin sheet 1 Molding equipment 12 Extruder 10 mold clamping device 16 Hopper 18 cylinder 20 hydraulic motor 22 accumulator 24 Plunger 28 T die 30 rollers 32 split mold 33 formwork 34 Suction part 341 First recess 342 Second recess 343 holes 344 lid member 345 connecting member 346 recess 347 suction path 33-1 Upper part of frame 33-2 Bottom of frame 100 contact surface 101 gap 116 cavity 118 Pinch-off part 120 Vacuum suction chamber 122 Suction hole 151 Sealed hollow part 201 1st formwork 200 Second formwork