JP2019098533A - Molding machine, method of producing molded article, and pinch device - Google Patents

Abstract

A molding machine capable of suppressing the opening of a sealing portion formed in a parison by a pinch device is provided. According to the present invention, a molding machine includes a head, a pinch device, and a pair of split molds, and the head is configured to extrude a cylindrical parison formed of a molten resin. The pinch device is configured to sandwich and seal the parison above the cavities of the pair of split molds, and the pair of split molds with the parison disposed therebetween The pair of split molds are clamped to form the parison, and the pinch device is configured to sandwich the parison between the first and second pinch parts, and the first pinch part is A molding machine having a tapered shape that tapers toward the second pinch portion is provided. [Selection] Figure 1

Description

  The present invention relates to a molding machine, a method of manufacturing a molded body, and a pinch device.

  Patent Document 1 discloses a configuration in which a pinch device is provided between a head for extruding a cylindrical parison and a divided mold for forming the parison, and the lower end of the parison is sandwiched and sealed by a pair of pinch blades of the pinch device. It is done.

JP-A-4-298321

  In Patent Document 1, the pair of pinch blades is opened after sandwiching and sealing the lower end of the parison. According to the configuration of Patent Document 1, when the inventors of the present invention have studied, when the sealing portion at the lower end of the parison is opened due to the weight or tension of the parison itself after the pair of pinch blades is opened. I noticed that there was.

  This invention is made in view of such a situation, and provides the molding machine which can suppress that the sealing part formed in the parison by a pinch apparatus opens.

  According to the present invention, there is provided a molding machine comprising a head, a pinch device, and a pair of divided dies, wherein the head is configured to push out a cylindrical parison formed of a molten resin, and the pinch The apparatus is configured to sandwich and seal the parison above the cavities of the pair of split molds, and the pair of split molds is configured to hold the parison therebetween and the pair of split molds The mold is clamped to form the parison, and the pinch device is configured to hold the parison at the first and second pinch portions, and the first pinch portion is a second pinch portion. A molding machine is provided, having a tapered shape that tapers towards.

  The inventors of the present invention conducted intensive studies, and the pinch device described in Patent Document 1 has sufficient pressure applied to the parison by the pair of pinch blades because the opposing surfaces of the pair of pinch blades are both flat surfaces. It has been found that the welding between the inner surfaces of the parison may become insufficient when the parison is held between the pair of pinch blades without being enlarged.

  And based on such knowledge, it is added to the parison by the first and second pinch portions by configuring the first pinch portion of the pinch device to have a tapered shape which is tapered toward the second pinch portion. The pressure was sufficiently increased, and it was found that the welding strength between the inner surfaces of the parison when the parison was held by the first and second pinch portions could be sufficiently enhanced, and the present invention was achieved.

Hereinafter, various embodiments of the present invention will be illustrated. The embodiments shown below can be combined with one another.
Preferably, in the forming machine described above, the second pinch portion is a forming machine in which the surface facing the first pinch portion is flat or concave.
Preferably, in the forming machine described above, the second pinch portion is a forming machine whose surface facing the first pinch portion is concave.
Preferably, in the forming machine described above, the concave shape is similar to the tapered shape.
Preferably, in the forming machine described above, the pinch device is an end from a center in a height direction of the first and second pinch portions in a closed state in which the first and second pinch portions sandwich the parison. And the spacing between the first and second pinch portions is configured to increase.
Preferably, in the molding machine described above, the tapered shape is a molding machine in which the radius of curvature of the curved portion of the tip is 2 to 10 mm.
Preferably, in the molding machine described above, the tapered shape is a cross-sectional shape that is constant along the depth direction.
Preferably, the first and second pinch portions are molding machines having a height of 15 mm to 25 mm.

  According to another aspect of the present invention, there is provided a method of producing a molded article using the above-mentioned molding machine, which comprises an extrusion step, a pinch step, and a molding step, and in the extrusion step, molten resin from the head Extruding the tubular parison formed in the step (c), and holding and sealing the parison above the cavities of the pair of split dies in the pinching step; and in the forming step, the parison of the pair of split dies A method is provided, wherein the parison is formed by clamping the pair of split molds with the parison arranged therebetween.

  According to yet another aspect of the present invention, there is provided a pinch device having a first and a second pinch portion, wherein the first and second pinch portions are configured to sandwich a parison, and the first pinch portion is configured to A pinch device is provided which has a tapered shape that tapers towards a two-pinch portion, and the second pinch portion has a concave surface facing the first pinch portion.

The structure of the molding machine 1 of one Embodiment of this invention is shown. It is a perspective view which shows the state in which pinch part 3a, 3b of the pinch apparatus 3 is a closed state. It is a perspective view which shows the state which pinch part 3a, 3b of the pinch apparatus 3 is an open state. It is sectional drawing corresponding to the AA cross section in FIG. 2 which pinch part 3a, 3b is a closed state. It is sectional drawing corresponding to the AA cross section in FIG. 2 which pinch part 3a, 3b is an open state. 6A is a cross-sectional view in the vicinity of the tip of the pinch portions 3a and 3b in which the pinch portions 3a and 3b are in a closed state, FIG. 6B is a cross-sectional view of only the pinch portion 3a in FIG. FIG. 6B is a cross-sectional view of only the pinch portion 3b in FIG. 6A. It is a sectional view (head 18 is a front view) showing the state where parison 23 was pushed out from head 18. FIG. 8 is a cross-sectional view (a head 18 is a front view) showing a state in which the parison 23 is nipped by the pinch portions 3a and 3b after the state of FIG. 7; It is sectional drawing (head 18 is a front view) of the state in which pinch part 3a, 3b was in the open state after the state of FIG. It is sectional drawing (head 18 is a front view) of the state in which the extrusion of the parison 23 was continued after the state of FIG. It is sectional drawing of the modification 1 corresponding to FIG. 6A. It is sectional drawing of the modification 2 corresponding to FIG. 6A. It is sectional drawing of the modification 3 corresponding to FIG. 6A.

  Hereinafter, embodiments of the present invention will be described. The various features shown in the embodiments described below can be combined with one another. In addition, the invention is established independently for each feature.

1. Configuration of Molding Machine 1 A molding machine 1 according to an embodiment of the present invention will be described with reference to FIGS. The molding machine 1 includes a resin supply device 2, a head 18, a pinch device 3, and a pair of split dies 19. The resin supply device 2 includes a hopper 12, an extruder 13, and an accumulator 17. The extruder 13 and the accumulator 17 are connected via a connecting pipe 25. The accumulator 17 and the head 18 are connected via a connecting pipe 27.
Each component will be described in detail below.

Hopper 12, extruder 13
The hopper 12 is used to introduce the raw material resin 11 into the cylinder 13 a of the extruder 13. The form of the raw material resin 11 is not particularly limited, but is usually in the form of pellets. The raw material resin 11 is, for example, a thermoplastic resin such as polyolefin, and as the polyolefin, low density polyethylene (LDPE), linear low density polyethylene, high density polyethylene (HDPE), polypropylene, ethylene-propylene copolymer, and the like A mixture etc. are mentioned. The raw material resin 11 is introduced into the cylinder 13a from the hopper 12 and then melted by being heated in the cylinder 13a to become a molten resin. Further, it is conveyed toward the tip of the cylinder 13a by the rotation of a screw disposed in the cylinder 13a. The screw is disposed in the cylinder 13a and is conveyed while kneading the molten resin by its rotation. A gear device is provided at the proximal end of the screw, and the screw device is rotationally driven by the gear device.

<Accumulator 17, Head 18>
The molten resin 11 a formed by melting and kneading the raw material resin is extruded from the resin extrusion port of the cylinder 13 a and is injected into the accumulator 17 through the connecting pipe 25. The accumulator 17 includes a cylinder 17a and a piston 17b slidable therein, and the molten resin 11a can be stored in the cylinder 17a. Then, by moving the piston 17b after a predetermined amount of the molten resin 11a is stored in the cylinder 17a, the molten resin 11a is pushed out from the die slit provided in the head 18 through the connecting pipe 27 and suspended. The parison 23 is formed. The accumulator 17 may be incorporated in the head 18. The head 18 may also be provided with a blow nozzle (not shown) for blowing air into the parison 23.

<Pinch device 3>
As shown in FIGS. 8-9, the pinch device 3 pinches and seals the parison 23 above the cavities 19a of the pair of split molds 19 and seals the parison 23 with the sealing portion 23a. It is configured to form. The pinch device 3 is configured to sandwich the parison 23 by the first and second pinch portions 3a and 3b. The pinch device 3 may be provided above the split mold 19 and may be incorporated at a position above the cavity 19 a of the split mold 19.

  The pinch portions 3a and 3b are elongated plates. The length in the depth direction of the pinch portions 3a and 3b is, for example, 50 to 300 cm, and preferably 100 to 250 cm. Specifically, for example, specifically, for example, 50, 100, 150, 200, 250, It may be 300 cm and within the range between any two of the numerical values exemplified here. The thickness of the pinch portions 3a and 3b is, for example, 10 to 30 mm, preferably 15 to 25 mm, and specifically, for example, specifically, for example, 10, 15, 20, 25, 30 mm, It may be in the range between any two of the numerical values exemplified here. If the thickness is too small, the rigidity may be insufficient. If the thickness is too large, the weight may be excessive.

  Brackets 4a and 4b are attached to both ends of the pinch portions 3a and 3b, respectively. The brackets 4a and 4b are connected to the arms 5a and 5b, respectively. The pair of arms 5a are connected by the connecting rod 6a, and the pair of arms 5b are connected by the connecting rod 6b. The pinch portions 3a and 3b can be switched between the closed state shown in FIG. 2 and the open state shown in FIG. 3 by pivoting around the connecting rods 6a and 6b as shown in FIGS. It has become. The pinch device 3 sandwiches the parison 23 in the closed state and releases the parison 23 in the open state.

  The brackets 4a and 4b respectively include base portions 4a1 and 4b1 and arm portions 4a2 and 4b2. The arms 5a and 5b are fixed to the arms 4a2 and 4b2 by bolts or the like. The pinch portions 3a and 3b are fixed by bolts or the like in a state of being mounted on the base portions 4a1 and 4b1. The base portions 4a1 and 4b1 are provided with standing walls 4a3 and 4b3, and upper walls 4a4 and 4b4 extend from the standing walls 4a3 and 4b3 toward the parison 23 side. The pinch portions 3a and 3b are fixed in a state of being in contact with the standing walls 4a3 and 4b3 and positioned. Further, when the pinch portions 3a and 3b sandwich the parison 23, the repulsive force from the parison 23 is applied to the pinch portions 3a and 3b, but since the pinch portions 3a and 3b are in contact with the standing walls 4a3 and 4b3, Misalignment of the pinch portions 3a and 3b is suppressed.

  The length from the pinch portions 3a, 3b to the connecting rods 6a, 6b (that is, the turning radius of the pinch portions 3a, 3b) is, for example, 30 to 200 cm, preferably 50 to 150 cm, specifically For example, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200 cm, and any two of the numerical values exemplified here It may be in the range between them.

  The distance between the closest portions of the pinched portions 3a and 3b in the closed state is preferably 0.1 to 2 times, more preferably 0.5 to 1.5 times the thickness of the parison 23, and specifically, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3 , 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2 times, and may be in the range between any two of the numerical values exemplified here. If the interval is too large, sealing of the parison 23 may be insufficient. If the interval is too small, the parison 23 may be torn. The distance between the pinch portions 3a and 3b in the open state may be set so that the pinch portions 3a and 3b do not interfere with the parison 23.

  It is preferable that the distance between the pinch portions 3a and 3b in the closed state be configured to extend from the center in the height direction of the pinch portions 3a and 3b toward the end (upper end and lower end). According to such a configuration, when the parison 23 is held between the pinch portions 3a and 3b, the air can easily escape toward the end in the height direction, and the decrease in the welding strength due to the inclusion of the air can be suppressed. The distance between the pinched portions 3a and 3b at the end in the height direction is preferably 1.2 to 5 times the distance between the pinched portions 3a and 3b at the center in the height direction. .2, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5 times, and may be in the range between any two of the numerical values exemplified here. If this value is too small, air is likely to be taken in at the time of sandwiching, and if it is too large, welding strength may be reduced. In this embodiment, as shown in FIG. 6A, the gap G2 between the pinch portions 3a and 3b at the end in the height direction than the gap G1 (for example, 2 mm) at the center in the height direction of the pinch portions 3a and 3b. (Example: 3 mm) is larger.

  In the present embodiment, the pinch portions 3a and 3b are opened and closed by rotating around the connecting rods 6a and 6b, but the pinch portions 3a and 3b may be opened and closed by another mechanism. For example, the pinch portions 3a and 3b may be opened and closed by sliding the pinch portions 3a and 3b horizontally.

  The pinch portion 3a has a tapered shape 3a1 that tapers from the base surface 3a4 to the pinch portion 3b. The tapered shape 3a1 may be provided over the entire length of the pinch portion 3a in the depth direction, or may be provided over a part of the tapered shape 3a1. The ratio of the length of the portion where the tapered shape 3a1 is provided to the total length in the depth direction of the pinch portion 3a is, for example, 0.5 to 1, preferably 0.8 to 1, and specifically, For example, 0.5, 0.6, 0.7, 0.8, 0.9, 1 and may be in the range between any two of the numerical values exemplified here.

  By holding the parison 23 between the tapered shape 3a1 and the pinch portion 3b, it becomes possible to hold the parison 23 with high pressure, and the welding strength between the inner surfaces of the parison 23 is enhanced to open the sealing portion 23a. Is suppressed. The curved portion 3a2 is preferably provided at the tip of the tapered shape 3a1, and the curvature radius of the curved portion 3a2 is preferably 2 to 10 mm, and specifically, for example, 2, 3, 4, 5, 6, 7, It may be 8, 9, 10 mm, and may be in the range between any two of the numerical values exemplified here. If the radius of curvature is too small, the parison 23 may be broken, and if the radius of curvature is too large, sealing may be insufficient.

  The projection length L of the tapered shape 3a1 from the base surface 3a4 is, for example, 2 to 20 mm, preferably 3 to 10 mm, and specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 mm and may be in the range between any two of the numerical values exemplified here.

  The tapered shape 3a1 includes a pair of inclined portions 3a3 connected to the curved portion 3a2. The inclined portion 3a3 is preferably a flat surface. The angle α between the pair of inclined portions 3a3 is, for example, 30 to 150 degrees, preferably 45 to 120 degrees, more preferably 70 to 110 degrees, and specifically, for example, 30, 35 , 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 degrees, and It may be in the range between any two of the numerical values exemplified here. If the angle α is too small, the parison 23 may be broken. If the angle α is too large, the sealing may be insufficient. Further, if the angle α is too small, there is also a possibility that the parison 23 bites into the concave shape 3b1 of the pinch portion 3b and is difficult to be removed.

  The tapered shape 3a1 preferably has a constant cross-sectional shape along the depth direction. The tapered shape 3a1 may have a constant cross-sectional shape over the entire length in the depth direction, or may have a constant cross-sectional shape over part. The ratio of the length of a portion having a constant cross-sectional shape to the total length in the depth direction of the tapered shape 3a1 is, for example, 0.5 to 1, preferably 0.8 to 1, and specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1 and may be in the range between any two of the numerical values exemplified here.

  The pinch portion 3 b has a concave shape 3 b 1 that is recessed from the base surface 3 b 4 on the surface facing the pinch portion 3 a. The concave shape 3b1 may be provided over the entire length in the depth direction of the pinch portion 3b, or may be provided partially. The ratio of the length of the portion where the concave shape 3b1 is provided to the total length in the depth direction of the pinch portion 3b is, for example, 0.5 to 1, preferably 0.8 to 1, and specifically, For example, 0.5, 0.6, 0.7, 0.8, 0.9, 1 and may be in the range between any two of the numerical values exemplified here.

  By holding the parison 23 between the tapered shape 3a1 and the concave shape 3b1, it becomes possible to hold the parison 23 in a wide area, enhancing the welding strength between the inner surfaces of the parison 23, and opening the sealing portion 23a. Is suppressed. Further, as the tapered shape 3a1 and the concave shape 3b1 are engaged, displacement of the pinch portions 3a and 3b in the height direction is suppressed. The curved portion 3b2 is preferably provided at the bottom of the concave shape 3b1, and the radius of curvature of the curved portion 3b2 is preferably 4 to 12 mm. Specifically, for example, 4, 5, 6, 7, 8, 9, 10, 11 and 12 mm, and may be in the range between any two of the numerical values exemplified here. If the radius of curvature is too small, the parison 23 may be broken, and if the radius of curvature is too large, sealing may be insufficient.

  The concave shape 3b1 is preferably similar to the tapered shape 3a1. In this case, since the distance between the concave shape 3b1 and the tapered shape 3a1 is constant over a wide area, the thickness of the sealing portion 23a formed therebetween is also constant over a wide area.

  The depth of the concave shape 3b1 from the base surface 3b4 is, for example, 2 to 20 mm, preferably 3 to 10 mm, and specifically, for example, 2, 3, 4, 5, 6, 7, 8, 9 , 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 mm, and may be in the range between any two of the numerical values exemplified here.

  The concave shape 3b1 includes a pair of inclined portions 3b3 connected to the curved portion 3b2. The inclined portion 3b3 is preferably a flat surface. The angle β between the pair of inclined portions 3b3 is, for example, 30 to 150 degrees, preferably 45 to 120 degrees, and specifically, for example, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150 degrees, and any of the numerical values exemplified here It may be in the range of If the angle β is too small, the parison 23 may be broken. If the angle β is too large, the sealing may be insufficient. The angle β may be the same as or different from the angle α.

  The concave shape 3b1 preferably has a constant cross-sectional shape along the depth direction. The concave shape 3b1 may have a constant sectional shape over the entire length in the depth direction, or may have a constant sectional shape over part. The ratio of the length of a portion having a constant cross-sectional shape to the total length in the depth direction of the concave shape 3b1 is, for example, 0.5 to 1, preferably 0.8 to 1, and specifically, for example, 0.5, 0.6, 0.7, 0.8, 0.9, 1 and may be in the range between any two of the numerical values exemplified here.

<Divided mold 19>
The parison 23 is guided between the pair of split dies 19. The pair of split molds 19 is configured to be clamped in a state where the parison is disposed therebetween to mold the parison 23 into a shape along the inner surface of the cavity 19a. This gives a molded body of the desired shape.

2. Method of Manufacturing Molded Body Here, a method of manufacturing a molded body according to an embodiment of the present invention will be described with reference to FIGS. 7 to 10. The method of the present embodiment comprises an extrusion step, a pinch step, and a forming step. The details will be described below.

2-1. Extrusion Process In the extrusion process, as shown in FIG. 7, the cylindrical parison 23 formed of the molten resin 11 a is extruded from the head 18. Air may be blown into the parison 23 from a blow nozzle.

2-2. Pinch Process In the pinch process, as shown in FIG. 8, by closing the pinch portions 3a and 3b, the parison 23 is held using the pinch portions 3a and 3b above the cavity 19a of the split mold 19. And sealing to form a sealing portion 23a. The sealing portion 23 a is formed near the lower end of the parison 23. After forming the sealing portion 23a, as shown in FIG. 9, the pinch portions 3a and 3b are opened.

  By the way, the parison 23 increases in weight as the thickness, diameter and length increase. As the weight of the parison 23 is larger, as shown in FIG. 9, the sealing portion 23a is more easily opened after the pinch portions 3a and 3b are opened. Moreover, the sealing part 23a is easy to open, so that the air pressure in the parison 23 is high. For this reason, when at least one of the thickness, the diameter, the length, and the pressure of the parison 23 is large, the significance of applying the present invention is particularly large.

  The thickness of the parison 23 is, for example, 1 to 10 mm, preferably 2 to 6 mm, and specifically, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 mm. It may be in the range between any two of the numerical values exemplified here. The diameter of the parison 23 is, for example, 10 to 100 cm, preferably 30 to 80 cm, and specifically, for example, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 cm The value may be in the range between any two of the numerical values exemplified here. The length from the lower end of the head 18 to the sealing portion 23a just before the split mold 19 is clamped is, for example, 50 to 500 cm, preferably 100 to 400 cm, specifically, For example, it is 50, 100, 150, 200, 250, 300, 350, 400, 450, 500 cm, and may be in the range between any two of the numerical values exemplified here.

  Furthermore, the pressure in the parison 23 at a time immediately before the mold part 19 is clamped is, for example, 0.1 to 1.0 MPa, preferably 0.12 to 0.8 MPa, and more preferably 0.2 to 0.5 MPa, and specifically, for example, 0.1, 0.12, 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0 And 0.8, 0.9, and 1 MPa, and may be in the range between any two of the numerical values exemplified herein. The pressure of the air blown out from the blow nozzle for blowing the air into the parison 23 is, for example, 0.15 to 1.5 MPa, preferably 0.2 to 1.0 MPa, and specifically, for example, specifically, for example, , 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5 MPa, and is exemplified here It may be in the range between any two of the numerical values.

2-3. Forming Step After the pinching step, as shown in FIG. 10, the extrusion of the parison 23 is continued. At this time, by blowing air into the parison 23, the parison 23 can be inflated. When the sealing portion 23a reaches the lower side (preferably, the lower side than the split mold 19) than the cavity 19a of the split mold 19, the split mold 19 is clamped. As a result, the parison 23 is shaped into a shape along the inner surface of the cavity 19a to obtain a compact. After clamping, air may or may not be blown into the parison 23.

3. Modified Example In the following modified example, the shapes of the pinch portions 3a and 3b are different from the above embodiment.

3-1. First Modified Example In the above embodiment, the angle α between the pair of inclined portions 3a3 is 90 degrees, but in this modified example, it is 60 degrees. Even in such a form, the effect of improving the welding strength can be obtained.

3-2. Second Modification In the above embodiment, the concave shape 3b1 is similar to the tapered shape 3a1, but in the present modification, the concave shape 3b1 is not similar to the tapered shape 3a1. Even in such a form, the effect of improving the welding strength can be obtained.

3-3. Third Modified Example In this modified example, the pinch portion 3 b has a flat surface facing the pinch portion 3 a. Even in such a form, the effect of improving the welding strength can be obtained.

4. Other Embodiments In the above embodiment, the pinch device 3 is configured to sandwich and seal the parison 23 above the cavity 19 a of the split mold 19, but the parison 23 below the cavity 19 a May be configured to be sandwiched and sealed. In that case, the forming step may be performed with the pinched portions 3a and 3b closed, or the pinched portions 3a and 3b may be opened before or during the forming step.
In addition, after the pinch device 3 sandwiches and seals the parison 23 on the upper side of the cavity 19a of the split mold 19 to form the sealing portion 23a, sealing is performed while the pinch portions 3a and 3b are closed. The pinches 3a and 3b may be moved downward together with the portion 23a.

1: molding machine 2: resin supply device 3: pinch device 3a: pinch portion 3a1: tapered shape 3a2: curved portion 3a3: inclined portion 3a4: base surface 3b: pinch portion 3b1: concave shape 3b2: curved portion 3b3: inclined portion 3b4 Reference: Base surface 4a: Bracket 4a1: Base 4a2: Arm 4a3: Standing wall 4a4: Upper wall 4b: Bracket 4b1: Base 4b2: Arm 4b3: Standing wall 4b4: Upper wall 5a: Arm 5b: Arm 6a : Connecting rod 6b: Connecting rod 11: Raw material resin 11a: Melt resin 12: Hopper 13: Extruder 13a: Cylinder 17: Accumulator 17a: Cylinder 17b: Piston 18: Head 19: Divided mold 19a: Cavity 23: Parison 23a: Sealing part 25: Connection pipe 27: Connection pipe L: Protruding length

Claims (10)

A molding machine,
It has a head, a pinch device, and a pair of split dies,
The head is configured to extrude a tubular parison formed of a molten resin,
The pinch device is configured to sandwich and seal the parison above the cavities of the pair of split dies;
The pair of split molds is configured to clamp the pair of split molds and form the parison in a state where the parison is disposed therebetween.
The pinch device is configured to clamp the parison at first and second pinch portions,
The molding machine, wherein the first pinch portion has a tapered shape that tapers toward the second pinch portion. The molding machine according to claim 1, wherein
The second pinch portion is a molding machine in which the surface facing the first pinch portion is flat or concave. The molding machine according to claim 1 or 2, wherein
The second pinch portion is a molding machine in which the surface facing the first pinch portion is concave. The molding machine according to claim 3, wherein
The molding machine, wherein the concave shape is similar to the tapered shape. The molding machine according to claim 3 or 4, wherein
The pinch device is disposed between the first and second pinch portions from the center toward the end in the height direction of the first and second pinch portions in a closed state in which the first and second pinch portions sandwich the parison. A molding machine, configured to spread the spacing of the. The molding machine according to any one of claims 1 to 5, wherein
The said tapered shape is a molding machine whose curvature radius of the curve part of a front-end | tip is 2-10 mm. The molding machine according to any one of claims 1 to 7, wherein
The tapered shape is a molding machine having a constant cross-sectional shape along the depth direction.   The molding machine, wherein the first and second pinch portions have a height of 15 mm to 25 mm. A method of producing a molded body using the molding machine according to any one of claims 1 to 8,
Equipped with an extrusion process, a pinch process, and a forming process,
In the extrusion step, a tubular parison formed of a molten resin is extruded from the head,
In the pinching step, the parison is held and sealed above the cavities of the pair of split molds,
In the forming step, the parison is formed by clamping the pair of divided dies while the parison is disposed between the pair of divided dies. A pinch device having first and second pinch portions, wherein
Configured to sandwich the parison at the first and second pinch portions,
The first pinch portion has a tapered shape which is tapered toward the second pinch portion,
The second pinch portion is a pinch device in which the surface facing the first pinch portion is concave.