JP4238721B2 - Cap mold, cap injection molding method and cap - Google Patents

Description

  The present invention relates to a mold for injection-molding a cap that can be easily separated and collected, and to a method for injection-molding a cap using the mold, and the cap is molded by an injection-molding method for a cap using the mold. It relates to the cap.

  In recent years, from the viewpoint of effective use of resources and prevention of pollution, used containers are collected and reused, that is, so-called recycling.

  However, since a container such as a bottle and a cap attached to the mouth of the container are generally made of different materials, it is necessary to separate the container and the cap and perform so-called separate collection for recycling.

  A cap having a weakened portion that can be cut has been known as a container that can easily separate and collect the container and the cap. According to the cap having the weakened portion, the degree of fitting of the cap to the container can be weakened by tearing the weakened portion, whereby the cap can be easily removed from the container.

The synthetic resin cap described in Japanese Patent Application Laid-Open No. 2000-255616 (Patent Document 1) filed earlier by the present applicant is an example of a cap having a weakened portion that can be torn. The cap described in the publication has a circumferential ridge weakening portion on the inner peripheral side of the hinge fixing portion in the inner lid as a part of the weakened portion. A slit as an example of the weakened portion is described.
JP 2000-255616 A

  Conventionally, when a synthetic resin cap having a circumferential weakened portion as described in Patent Document 1 is molded by injection molding, molding is performed using a molding die as shown in FIG. The conventional example shown in FIG. 3 shows a case where a slit is provided as an example of the circumferential weakening portion.

  In the mold shown in FIG. 3, the core that forms the front side of the inner lid 52 of the cap 50 includes a first front core 56 that forms the outer wall 54a of the outer cylinder 54, the outer wall 55a of the engagement cylinder 55, and the like. A second front side core 58 that molds the inner wall 55b of the joint cylinder 55, an outer wall 57a of the casting cylinder 57, and the like, a third front core 59 that molds the inner wall 57b of the casting cylinder 57, and the surface of the central lid portion 60 The core that forms the back side of the inner lid 52 of the cap 50 is composed of an inner wall 62b of the seal cylinder 62, an inner wall 54b of the outer cylinder 54, an outer wall 63a of the inner cylinder 63, and the like. The first back side core 64 for molding the inner wall 63b, the inner wall 63b of the inner cylinder 63, the second back side core 65 for molding the back surface 60b of the central lid 60, and the like. The cap 50 is formed by connecting an inner lid 52 to an outer lid 53 via a hinge portion 51. In FIG. 3, a mold for molding the hinge portion 51, the outer lid 53, etc. is shown. It is omitted.

  The slit 66 as an example of the circumferential wrinkle weakening portion is formed on the inner peripheral side of the hinge fixing portion 67 so as to be cut from the back side with respect to the lower end flange portion 54c of the outer cylinder 54. Molded by the first back core 64 in the core molding the 50 back side.

  That is, as shown in detail in the enlarged cross-sectional view of the first back-side core 64 in FIG. 4, the inner wall 54 b of the outer cylinder 54 and the outer wall 63 a of the inner cylinder 63 are formed at the distal end portion 64 a of the first back-side core 64. In addition to the first protrusion 64b to be formed, a second protrusion 64c for forming the slit 66 is formed at a distance 64d from the first protrusion 64b, whereby the slit 66 can be formed.

  The slit-forming second protrusion 64c at the front end 64a of the first back-side core 64 enables the slit 66 to be formed as described above at the stage of forming the cap 50. In the stage of forming the back side core 64, it is difficult to process the front end portion 64a of the first back side core 64. That is, the second protrusion 64c for forming the slit 66 is formed with an interval 64d between the inner wall 54b of the outer cylinder 54 and the first protrusion 64b for forming the outer wall 63a of the inner cylinder 63. Therefore, when the width of the interval 64d is narrow, it becomes difficult to cut out the relative portion (that is, the portion where the interval 64d is formed) of the first protrusion 64b and the second protrusion 64c.

  That is, when the cap is molded by the conventional mold shown in FIGS. 3 and 4, there is a problem that it is difficult to process the mold.

  In view of the above circumstances, the present invention aims to obtain a cap mold that can be easily processed, and an object of the present invention is to obtain a cap injection molding method using the mold. In addition, an object of the present invention is to obtain a cap that is molded by an injection molding method of a cap using the mold.

  The present invention that achieves the above object will be described as follows.

The present invention includes an inner lid and an outer lid connected via a hinge portion, and has a circumferential direction weakening portion that weakens the outer cylindrical collar portion of the outer cylinder in the inner lid at a position corresponding to the hinge portion. A cap mold for injection molding a synthetic resin cap, the cap mold comprising an upper cavity including an outer cylinder outer wall core for molding an outer wall of the outer cylinder in the cap, and at least the molding the inner wall surface of the tubular sealing section having an inner wall surface and a lower surface and longitudinal lines of weakness of the outer tubular portion of the cap, a lower Kyabitei including rear outer core consists, outer cylindrical exterior wall core, the outer It is assumed that an arc-shaped projecting portion is formed at the tip portion forming the contact surface of the tubular collar portion, and the arc-shaped projecting portion of the outer cylinder outer wall core forms the circumferential weakened portion of the cap. Characterized by things It is a mold for the cap.

The present invention includes an inner lid and an outer lid that are connected via a hinge portion, and the inner lid is continuous with the injection cylinder portion, the engagement cylinder portion that is continuous with the injection cylinder portion, and the engagement cylinder portion. And an outer cylinder having an outer cylinder collar portion that comes into contact with an outer lid collar portion of the outer lid at a lower end, and a seal cylinder portion that is continuous below the outer cylinder and has a longitudinal weakening line, An injection molding method for a cap made of synthetic resin having a circumferential direction weakening portion for weakening an outer cylindrical flange portion of the outer cylinder in the inner lid at a position corresponding to the hinge portion, wherein the injection molding method is The said circumferential direction weakening part is shape | molded by the circular-arc-shaped protrusion provided in the front-end | tip part of the said outer cylinder outer wall core in the upper cavity of the shaping | molding die for caps of the said Claim 1. And a synthetic resin cap injection molding method.

The present invention includes an inner lid and an outer lid that are connected via a hinge portion, and the inner lid is continuous with the injection cylinder portion, the engagement cylinder portion that is continuous with the injection cylinder portion, and the engagement cylinder portion. And an outer cylinder having an outer cylinder collar portion that comes into contact with an outer lid collar portion of the outer lid at a lower end, and a seal cylinder portion that is continuous below the outer cylinder and has a longitudinal weakening line, 2. A cap made of synthetic resin having a circumferential wrinkle weakening portion for weakening an outer cylinder flange portion of the outer cylinder in the inner lid at a position corresponding to the hinge portion , wherein the circumferential wrinkle weakening portion is the above-mentioned claim 1. A cap made of synthetic resin, characterized in that it is formed by an arc-shaped protrusion provided at the tip of the outer cylinder outer wall core in the upper cavity of the cap mold.

  Further, the present invention is the cap mold, wherein the circumferential weakening portion in the cap formed by the arc-shaped protrusion of the outer cylinder outer wall core is a groove. This is a mold for use.

  According to the present invention, in the cap molding die, the circumferentially weakened portion of the inner lid of the cap is molded by an arc-shaped protrusion provided at the tip of the outer cylinder outer wall core that molds the outer wall of the outer cylinder. Therefore, it is not necessary to form the first protrusion and the second protrusion at an interval at the tip of the core in order to form the circumferential weakened part as in the conventional mold, A core for forming the circumferential weakened portion can be formed simply by forming an arc-shaped protrusion at the tip of the outer cylinder outer wall core. That is, according to the present invention, the cap mold does not need to be processed as difficult as in the conventional mold, and a core for forming the circumferential weakened portion can be obtained by simple processing. it can.

  Therefore, according to the present invention, it is a cap molding die for molding a cap made of synthetic resin having a circumferential weakened portion on the inner peripheral side of the hinge portion, but the cap molding is easy to process the mold. A cap can be obtained, a cap injection molding method using the cap molding die, and a cap molded by the cap injection molding method using the cap molding die can be obtained.

  Furthermore, according to the present invention, in the cap mold, only one protrusion can be provided at the tip of the core for molding the circumferentially weakened portion. The strength of the core tip can be made stronger than that in which two protrusions are formed at a distance from the tip of the core forming the direction weakening portion.

  Further, in the above-described conventional mold, the interval between the first protrusion and the second protrusion in the core for forming the circumferentially weakened portion is the space for the molded product of the outer cylinder. If the distance between the first protrusion and the second protrusion is narrow, it becomes difficult to form a relative portion between the first protrusion and the second protrusion. Therefore, the first protrusion and the second protrusion It is difficult to narrow the space between the parts to narrow the space for the molded product of the outer cylinder in the cap to be molded. That is, when the cap is molded by the conventional mold, it is difficult to reduce the thickness of the outer cylinder in the inner lid of the molded cap. On the other hand, according to the present invention, since the core for molding the circumferentially weakened portion is the outer cylinder outer wall core, the outer cylinder molded on the inner wall side of the outer cylinder outer wall core is made thinner. Even if it does, formation of the core for outer cylinder outer walls will not become difficult. That is, according to the present invention, the thickness of the outer cylinder in the cap to be molded can be reduced.

  Furthermore, in the conventional mold described above, in order to facilitate the formation of the relative portions of the first protrusion and the second protrusion in the core for forming the circumferential weakened portion, the first protrusion Although it is conceivable to increase the distance between the second protrusions, the distance between the first protrusions and the second protrusions should be increased while sufficiently securing the thickness of the second protrusions. Since the first protrusion must be thinned, in such a case, not only the strength of the first protrusion of the core that forms the circumferentially weakened part is weakened, but also the outer cylinder is formed. Since a part of the product space is partially widened and a part having a thick wall is formed in the outer cylinder of the cap, the inner wall surface of the outer cylinder of the cap and the outer peripheral surface of the mouth of a container such as a bottle This will reduce the adhesion. On the other hand, according to the present invention, as described above, the core for forming the circumferential weakened portion is formed simply by forming an arc-shaped protrusion at the tip of the outer cylinder outer wall core in the molding die. Therefore, in the mold, the strength of the core that molds the circumferentially weakened portion is not weakened, and there is no part of the outer cylinder that is partly wide. Since there is no partial thickening in the outer cylinder, the inner wall surface of the outer cylinder can be uniformly adhered to the outer peripheral surface of the mouth of a container such as a bottle over the entire circumference. .

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows an example of an embodiment of a cap mold according to the present invention, which is a longitudinal section of the cap mold and the cap, and FIG. 2 is a partially enlarged view of FIG.

  In FIG. 1, a cap mold 1 is a mold for molding a cap 30 by injection molding, and a molded product space corresponding to the shape of the cap 30 is formed inside the mold. The cap 30 is formed by cooling and solidifying the molten synthetic resin material filled in the space.

  Here, before specifically explaining the mold 1, the cap 30 molded by the mold 1 will be described. The cap 30 includes an inner lid 31, an outer lid 32, a hinge portion 33 that connects the inner lid 31 and the outer lid 32, and the like. In the cap 30, the inner lid 31 includes a central lid portion 34 that closes a mouth portion of a container such as a bottle, a barrel portion 35 that is provided so as to stand up around the central lid portion 34, and a barrel portion 35. This is an example of an outer cylinder, which is an engagement cylinder part 36 having an engagement recess 36a that is provided on the outer peripheral side via a top wall part 40 and that engages with an engagement protrusion 32b of the outer lid 32 on the outer wall. An engagement recess 36a is provided below the cylinder 36, and an inner surface is provided with a fitting surface 37b with an upper outer wall of a mouth portion of a container such as a bottle, and a lower end of the outer lid 32 with the outer lid flange 32a. An outer cylinder part 37 having an outer cylinder collar part 37a in contact with the outer cylinder part 37 is provided below the outer cylinder part 37 via the outer cylinder collar part 37a, and a seal surface 38a is formed on the inner wall with the lower outer wall of the mouth part of a container such as a bottle. It is provided so that it hangs down from the seal cylinder part 38 and the central lid part 34, and is attached to a container such as a bottle on the outer wall. Consisting inner cylindrical portion 39, and the like having a fitting portion 39a of the mouth portion upper inner wall that. Reference numeral 41 denotes a pull ring for tearing a fissure formed in the central lid portion 34, and 42 denotes a support column.

  Further, in the cap 30, the outer lid portion 37 a is partially provided on the inner lid 31 at a position on the inner peripheral side of the hinge portion 33 as a weakened portion for facilitating separation of the cap 30 and the container. The circumferential direction weakening groove part 37g as an example of the circumferential direction weakening part is formed, and a continuous part with one end of the circumferential direction weakening groove part 37g is used as the end part on the inner wall of the seal cylinder part 38, The continuous part of the longitudinal weakening line (not shown) which goes to the inner wall of the seal cylinder part 38 from the end part to a vertical direction and the other end of the circumferential direction weakening groove part 37g is made into the end part, A circumferential weakening line 37h is formed on the inner wall in the circumferential direction. That is, according to the cap 30, when the container is separated and collected, if the outer lid 32 is pulled downward from the opened state, the stress is applied to both ends of the circumferential direction weakening groove portion 37g, that is, the longitudinal direction weakening line and the circumferential direction. Since it concentrates on the end part of the weakening line 37h, the longitudinal direction weakening line and the circumferential direction weakening line 37h which were formed in the seal cylinder part 38 used as the seal part with a container can be easily torn off, and cap 30 Can be easily separated from the container.

  The molding die 1 for molding the cap 30 configured as described above will be specifically described. Note that FIG. 1 does not show all the molds for molding the cap 30, and illustration of some molds (for example, a mold for molding the inner surface of the outer lid 32) is omitted.

  In the mold 1, the parting line PL is the same surface as the contact surface 37 s of the outer cylinder collar portion 37 a of the inner lid 31 and the contact surface 32 s of the outer lid collar portion 32 a of the outer lid 32 when the cap 30 is open. The upper cavity 2 is formed on the upper side and the lower cavity 3 is disposed on the lower side with the parting line PL as a boundary. In the upper cavity 2, a plurality of cores for forming the front surface of the inner lid 31 are inserted and arranged. On the other hand, a plurality of cores for molding the back surface of the inner lid 31 are inserted into the lower cavity 3, and the lower cavity 3 is arranged with the outer wall surface 38 b of the seal cylinder portion 38 of the inner lid 31. The outer surface 32c of the outer lid 32 is also molded.

  The plurality of cores to be inserted into the upper cavity 2 are located on the outer peripheral side of the front side center core 4 and the front side center core 4 that form the upper surface of the central lid 34, the inner wall surface of the pull ring 41 and the pull ring post 42, and the like. The outer wall surface of the injection tube portion 35 is located on the outer peripheral side of the first intermediate core 5 and the first intermediate core 5 that form the outer wall surface of the pull ring 41 and the pull ring column 42, the inner wall surface 35a of the injection tube portion 35, and the like. 35b, the top surface of the top wall portion 40, the second intermediate core 6 that forms the inner wall surface 36b of the engagement cylinder portion 36, and the like, and is positioned on the outer peripheral side of the second intermediate core 6, and the engagement cylinder portion 36 The outer wall surface 36c (including the engagement recess 36a), the outer wall surface 37c of the outer cylinder portion 37, the contact surface 37s of the outer cylinder flange portion 37a, and the like are molded, and the outer cylinder outer wall which is an example of the outer cylinder outer wall core It consists of a core 7. In addition, inside the front-side center core 4, one end opens into the molded product space of the central lid body part 34, and the other end is connected to an injection device (not shown) to inject molten synthetic resin into the molded product space. Is formed.

  The outer cylinder outer wall core 7 forms the contact surface 37s of the outer cylinder collar portion 37a as described above. As shown in FIG. 1 and FIG. 2 showing an enlarged view of a part of the outer cylinder outer wall core 7. The tip 7a for forming the contact surface 37s of the outer cylinder collar 37a partially weakens the outer cylinder collar 37a at the position on the inner circumference side of the hinge part 33 of the inner lid 31, An arc-shaped protrusion 7b that forms a circumferentially weakened groove 37g as an example of the weakened portion is formed. Note that the shape and size of the arc-shaped protrusion 7b define the shape and size of the circumferentially weakened groove portion 37g, but in this embodiment, the shape (the shape of the groove portion 37g is specified). Is a circular arc with a square cross section, and its width (which defines the width of the groove 37g) is the same as the hinge width in the hinge 33, and its height (which defines the depth of the groove 37g) is 1.5 millimeters. It is said. However, the shape and size of the arc-shaped protrusion 7b can be changed as appropriate, and since the protrusion 7b can be easily formed as described later, the degree of freedom in design is high.

  The plurality of cores inserted into the lower cavity 3 are positioned on the outer peripheral side of the center core 8, the back side center core 8 that molds the lower surface of the central lid portion 34, the inner wall surface 39 a of the inner cylinder portion 39, etc. The outer wall surface 39b of the inner tube portion 39, the lower surface of the top wall portion 40, the inner wall surface of the outer tube portion 37, that is, the fitting surface 37b, the lower surface of the outer tube portion 37, and the inner wall surface of the seal tube portion 38, It consists of a back-side outer core 9 for molding the sealing surface 38a and the like. The fitting surface 37b of the outer cylinder portion 37 formed by the back outer core 9 is formed with an annular fitting portion 37d that fits into the mouth outer wall recess of a container such as a bottle. By making the joint part 37d into an annular shape, the sealing performance with the mouth part of a container such as a bottle can be improved, and the fitting part 37d can be fitted around the entire mouth part of a container such as a bottle. Therefore, heat resistance can also be improved.

  Using the molding die 1 configured as described above, the molded product space inside the molding die 1 is filled with a molten synthetic resin material injected from an injection device (not shown) via the gate 4a, and the filled molten synthetic resin material is used. By cooling and solidifying, the cap 30 having the circumferentially weakened groove portion 37g can be formed.

  In the molding die 1, as described above, the outer peripheral wall weakening groove portion 37 g that can weaken the outer cylindrical flange portion 37 a in the inner lid 31 of the cap 30 is formed on the outer cylindrical outer wall that forms the outer wall surface 37 c of the outer cylindrical portion 37. It can shape | mold by the circular-arc-shaped protrusion 7b provided in the front-end | tip part 7a of the core 7 for an object. As a result, it is not necessary to form two protrusions at the front end of the core at intervals in order to obtain the core for forming the circumferential weakened portion as in the conventional mold described above, but only the outer wall of the outer cylinder A core capable of forming the circumferentially weakened groove portion 37g can be obtained simply by forming the arc-shaped protrusion 7b at the tip 7a of the core 7 for use. That is, in the mold 1, there is no need for difficult machining as in the conventional mold described above, and a core capable of forming the circumferentially weakened groove portion 37 g can be obtained by simple processing.

  Therefore, according to the shaping | molding die 1, a shaping | molding die can be made easy.

  Furthermore, in the mold 1, only one of the arc-shaped protrusions 7 b can be formed on the tip 7 a of the outer cylinder outer wall core 7 that forms the circumferential weakening groove 37 g. Compared with a core that molds the circumferentially weakened portion in the conventional mold, the tip of the core that molds the circumferentially weakened portion is compared to a core that forms two circumferentially spaced tip portions like the core that molds the circumferentially weakened portion. The strength can be increased.

  Furthermore, in the mold 1, the core for forming the circumferential weakening groove portion 37g is the outer cylinder outer wall core 7, so that the thickness of the outer cylinder portion 37 formed on the inner wall side of the outer cylinder outer wall core 7 is small. Even if it is made thinner, it does not become difficult to form the outer cylinder outer wall core 7. That is, according to the mold 1, the thickness of the outer cylinder portion 37 in the cap 30 can be formed thin.

  More specifically, in the mold 1, the core for forming the circumferentially weakened groove portion 37 g can be formed simply by forming the arc-shaped protrusion 7 b at the tip 7 a of the outer cylinder outer wall core 7. The outer cylinder portion 37 does not have a partially wide space in the molded product space, and the outer cylinder portion 37 of the cap 30 does not partially have a thick portion. The fitting surface 37b and the fitting portion 37d formed on the inner wall of the portion 37 can be brought into close contact with the outer peripheral surface of the mouth of a container such as a bottle over the entire circumference.

1 shows an example of an embodiment of a cap mold according to the present invention, and is a longitudinal section of a cap mold and a cap. FIG. 2 is an enlarged view of a part of FIG. 1. The conventional mold for caps is shown, It is a longitudinal cross-sectional view of the mold for caps and a cap. FIG. 4 is an enlarged view of a part of FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mold 2 Upper cavity 3 Lower cavity 4 Front center core 5 1st intermediate core 6 2nd intermediate core 7 Core for outer cylinder outer wall 7a Core tip for outer cylinder outer wall 7b Arc shape of core for outer cylinder outer wall Projection 8 Back side center core 9 Back side outer core 30 Cap 31 Middle lid 32 Outer lid 33 Hinge part 37 Outer cylinder part 37a Outer cylinder collar part 37g Outer cylinder part circumferential direction weakening groove part

Claims (5)

Made of a synthetic resin comprising an inner lid and an outer lid connected via a hinge portion , and having a circumferential direction weakening portion for weakening the outer cylindrical collar portion of the outer cylinder in the inner lid at a position corresponding to the hinge portion A cap mold for injection molding a cap,
The cap mold includes an upper cavity including a core for an outer cylinder outer wall that molds an outer wall of the outer cylinder in the cap, a seal cylinder having at least an inner wall surface and a lower surface of the outer cylinder portion in the cap, and a longitudinal weakening line. A lower cavity including a back outer core that molds the inner wall surface of the part ,
The outer cylinder outer wall core has an arc-shaped protrusion at a tip portion forming the contact surface of the outer cylinder collar ,
An arc-shaped protrusion of the outer cylinder outer wall core forms the circumferential weakened portion of the cap. It consists of an inner lid and an outer lid that are connected via a hinge portion, and the inner lid is continuous with the injection tube portion, the engagement tube portion that is continuous with the injection tube portion, and at the lower end. An outer cylinder having an outer cylinder collar that comes into contact with the outer lid collar of the outer lid, and a seal cylinder having a longitudinal weakening line that is continuous below the outer cylinder and corresponds to the hinge An injection molding method for a cap made of synthetic resin having a circumferential ridge weakening portion for weakening an outer cylinder ridge portion of the outer cylinder in the inner lid at a position to be
The injection molding method is characterized in that the circumferentially weakened portion of the cap is provided with an arc-shaped protrusion provided at the tip of the outer cylinder outer wall core in the upper cavity of the cap mold according to claim 1. A method of injection molding a cap made of synthetic resin, characterized in that the cap is molded by the method described above. It consists of an inner lid and an outer lid that are connected via a hinge portion, and the inner lid is continuous with the injection tube portion, the engagement tube portion that is continuous with the injection tube portion, and at the lower end. An outer cylinder having an outer cylinder collar that comes into contact with the outer lid collar of the outer lid, and a seal cylinder having a longitudinal weakening line that is continuous below the outer cylinder and corresponds to the hinge A cap made of synthetic resin having a circumferential ridge weakening portion for weakening an outer cylinder ridge portion of the outer cylinder in the inner lid at a position to be,
The circumferential weakening portion is formed by an arc-shaped protrusion provided at the tip of the outer cylinder outer wall core in the upper cavity of the cap mold according to claim 1. Characteristic synthetic resin cap.   2. The cap molding die according to claim 1, wherein the circumferentially weakened portion of the cap formed by an arc-shaped protrusion of the outer cylinder outer wall core is a groove. Mold.   The synthetic resin cap according to claim 3, wherein the fitting portion on the fitting surface formed on the inner wall of the outer cylinder is annular.

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