JP2010125808A - Method of injection-molding cap, and cap - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prolong a life of an injection molding die for a cap with a damper evidence band, and to enhance quality of the cap. <P>SOLUTION: The method of injection-molding the cap molded integrally with the damper evidence band via a plurality of bridges provided in an inside of a micro clearance in a lower end of a cap body includes a plurality of protrusions 32a in parallel to the center axis C of a core 32 at a fixed distance, in an outer circumferential part of the core 32 forming an inner circumferential face shape of the damper evidence band of the molding die for forming the cap, is constituted to support a tip part of a projected part 13b of a molding part 13a of a slide core 13 forming shapes of the micro clearance and a plurality of bridges by end face parts 32b of the protrusions 32a, and molds the cap by injecting a fused resin into a cavity 11 of the molding die. The plurality of protrusions 32a is provided to be positioned in an intermediate portion between the adjacent bridges. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an injection molding method for a cap with a tamper-evidence band and a cap with a tamper-evidence band.

  Various types of caps with tamper evidence bands (hereinafter referred to as TE bands) for identifying unauthorized opening are known. One example is a cap having the shape disclosed in Patent Document 1, for example. The cap with a TE band has a shape in which a plurality of bridges are provided in a minute gap between the cap body and the TE band, and the cap body and the TE band are connected via the bridge.

  For example, when a cap with a TE band as shown in FIG. 4 is molded by an injection molding method, it is generally molded under a mold structure as shown in FIGS. 4, 5, 6, and 7 are all shown schematically. FIG. 4 shows a plan view (a) and sectional views (b, c) as seen from the top of the cap with the TE band. 5 is a cross-sectional view of a main part showing a molding die structure in a portion having a bridge, FIG. 6 is a cross-sectional view of a main portion showing a molding die structure in a portion having no bridge, and FIG. 7 is a slide core in FIGS. The top view of is shown.

  In FIG. 4, a cap 10 with a TE band has a shape in which a cap body 1 and a TE band 2 are connected by a plurality of bridges 4 in a minute gap 3. The cap body 1 includes a canopy portion 1a and a tube portion 1b, and a screw that is screwed with a screw of the container mouth portion is provided on the inner peripheral surface of the tube portion 1b. In addition, a locking shape that locks to the container mouth is formed on the inner peripheral surface of the TE band 2.

  Although the minute gap 3 is provided around the entire circumference, as shown in FIG. 4B, the cap body 1 and the TE band 2 are completely separated from each other in the part where the bridge 4 is not provided. . Further, in the part where the bridge 4 is provided, the cap body 1 and the TE band 2 are connected via the bridge 4 as shown in FIG.

  The TE band-equipped cap 10 having such a shape is generally formed by injection molding under the mold structure shown in FIGS. 5 and 6, reference numeral 11 denotes a fixed cavity of the mold, and has a gate 11a for injecting molten resin. 12 is a movable core, 13 is a slide core, and there are a pair (two) on the left and right in the figure. The slide core 13 slides in the left-right direction indicated by an arrow during mold clamping and one-side opening. Reference numeral 14 denotes a movable side template. PL is a parting line and shows a mating surface of a fixed type and a movable type.

  FIG. 5 shows a mold structure of a portion where the bridge 4 is provided. In FIG. 5, D, E, and F are vacant spaces formed by the fixed cavity 11 and the pair of slide cores 13 and the movable core 12. , That is, the vacant part D is the part forming the cap body 1, the vacant part E is the bridge 4, and the vacant part F is the TE band 2. It is a part to be molded.

  FIG. 6 shows a mold structure where there is no bridge 4, and in FIG. This is because the projecting tip surface of the slide core 13 (pointing to the projecting tip surface 13d in FIG. 7) is in contact with the outer peripheral surface of the movable core 12.

Q indicates the flow of the injected molten resin and flows in the direction of the arrow. That is, in FIG. 5, the molten resin injected from the gate 11a flows and is filled in the vacant space D → E → F, and the cap body 1, the bridge 4 and the TE band 2 are formed. It should be noted that the portion without the bridge 4 is blocked by hitting the slide core 13 as shown in FIG.
The molten resin that has struck the slide core 13 flows toward the vacant part E, and then flows through the vacant part E to the vacant part F.

  The shape of the minute gap 3 and the bridge 4 is determined by the pair of slide cores 13. As shown in FIG. 7, the pair of slide cores 13 that are split to the left and right have a molding portion 13 a on the inner peripheral portion thereof. As shown in the enlarged cross-sectional view, the molding portion 13a has a projecting portion 13b having a thickness t projecting around the inner circumferential direction and an outer peripheral portion 13e for molding the shape of the outer peripheral surface of the TE band 2. I am doing. Further, the molding portion 13a has a slit 13c cut from the protruding tip surface 13d at the tip of the protruding portion 13b. The shape of the outer peripheral surface of the bridge 4, the minute gap 3, and the TE band 2 is formed by the molding portion 13a. The minute gap 3 is formed by moving the slide core 13 in the opening direction when the mold is opened.

  The gap width of the minute gap 3 is determined by the thickness t of the protruding portion 13b of the molding portion 13a, and is determined in consideration of the identifiable accuracy of unauthorized opening. The number and size of the bridges 4 (thickness) are determined by the number and size of the slits 13c, but are determined in consideration of the breaking load force at the time of opening.

Japanese Utility Model Publication No. 5-75148

The cap with a TE band is molded under the above-described mold structure. However, if the gap width of the minute gap 3 is small (narrow), the following problems occur.
In order to reduce the gap width, it is necessary to reduce the thickness t of the protruding portion 13b of the molding portion 13a of the slide core 13.
In addition, the cap is formed by filling the vacant portion with the resin while applying a required filling pressure to the molten resin, but a flow pressure is generated in the resin flowing at that time.
If the thickness t of the protruding portion 13b of the molded portion 13a is thin, the protruding portion 13b of the molded portion 13a is deformed by warping to the TE band 2 side, that is, the vacant portion F side, due to the flow pressure of the molten resin. . In some cases, damage may occur. In particular, in a portion without the bridge 4, as shown in FIG. 6, the flow pressure of the molten resin is directly applied to the protruding portion 13b, and deformation such as warpage is likely to occur.

  If warpage or the like occurs in the protruding portion 13b of the molding portion 13a, the movement of the slide core 13 becomes worse, and galling or the like occurs in the TE band. In some cases, there is also a problem that the cap 10 with TE band does not release from the mold because the slide core 13 does not open completely when the mold is opened.

  The present invention has been made in view of the above problems, and has found an injection molding method under a mold structure that does not cause deformation such as warping of the slide core, and aims to improve mold life and quality. It is the purpose.

  As a means for solving the above-described problems, the cap injection molding method of the present invention is a cap injection molding in which a tamper evidence band is integrally molded through a plurality of bridges in a minute gap at the lower end of the cap body. In the method, a plurality of convex portions parallel to the central axis of the core for molding the inner peripheral surface shape of the tamper evidence band of the mold for molding the cap are provided at regular intervals, and the minute gap and the The tip of the slide core that forms the shape of a plurality of bridges is supported by the end face of the convex portion, and the cap is formed by injecting molten resin into the cavity of the mold. is there.

  Under this mold structure, the molten resin is injected into the cavity in a state where the end portion of the projecting portion provided on the core of the mold supports the tip of the slide core. Although the flow pressure of the molten resin is directly applied to the slide core, it can resist the flow pressure because the tip of the slide core is supported by the end face of the convex part provided on the core, and suppresses the occurrence of warpage etc. be able to. Moreover, occurrence of breakage can be prevented. Further, quality problems such as galling due to warpage described in the background art do not occur. That is, the life of the mold is extended and the quality of the cap is improved.

  The cap injection molding method of the present invention is characterized in that the plurality of convex portions are provided so as to be positioned at intermediate positions of the adjacent bridges.

  The site that is most greatly applied by the flow pressure of the molten resin applied to the slide core is an intermediate site between adjacent bridges. Accordingly, if a structure is provided in which a projecting portion is provided at the position of the intermediate portion to support the slide core, deformation such as warpage can be most effectively suppressed.

  Further, the cap of the present invention is a cap formed by integrally forming a tamper evidence band through a plurality of bridges in a small gap at the lower end of the cap body, and the tamper evidence band is formed on an inner peripheral surface of the tamper evidence band. A plurality of concave grooves parallel to the central axis are provided at regular intervals.

  With the above mold structure, a concave groove is formed on the inner peripheral surface of the tamper evidence band. That is, by providing a groove on the inner peripheral surface of the tamper evidence band, as described above, the slide core that is the mold is prevented from being deformed or damaged, and the effect of extending the life of the mold is obtained. . Further, since the concave groove is partially provided on the inner peripheral surface, the locking structure with the container mouth portion does not have much influence.

  The cap of the present invention is characterized in that the plurality of concave grooves are provided at intermediate portions of the adjacent bridges.

  By providing the concave groove at the intermediate portion between the adjacent bridges, as described above, the deformation and breakage of the slide core, which is a mold, are most effectively prevented.

  As described above in detail, when summarized roughly, the effects of extending the life of the mold and improving the quality of the parts can be obtained.

Embodiments for carrying out the present invention will be described below with reference to FIGS. 1, 2 and 3 are all schematically shown. FIG. 1 is a plan view and a cross-sectional view of a cap with a TE band. FIG. 1 (a) is a plan view and FIG. 1 (b). 1 is a cross-sectional view taken along line AA in FIG. 1, and FIG. 1C is a cross-sectional view taken along line BB in FIG. 2 is a cross-sectional view of the main part showing the molding die structure of the TE band-equipped cap bridge in FIG. 1, and FIG. 3 shows the molding mold structure of the TE band-capless bridging portion in FIG. The principal part sectional drawing shown is shown.
In addition, components having the same specifications as those of the mold structure described in the background art will be described with the same reference numerals.

First, the cap 20 with a TE band of the present embodiment is made of resin, and has a shape in which a cap body 21 and a TE band 22 are connected by a plurality of bridges 24 in a minute gap 23 as shown in FIG. . The cap body 21 includes a canopy portion 21a and a tube portion 21b.
Although not shown in the drawing, the inner peripheral surface of the cylindrical portion 21b has a screw that is screwed with the screw of the container mouth portion, and the inner peripheral surface of the TE band 22 has a container mouth portion and a screw. Engaging means for engaging is provided.
The TE band-equipped cap 20 of the present embodiment is different from the TE band-equipped cap described in the background art described above, as shown in FIGS. 1 (a), (b), and (c). This is that a plurality of concave grooves 22b are provided on the inner peripheral surface 22a. The rest of the shape is exactly the same.

  The concave groove 22b is provided in parallel with the central axis C of the TE band 22 indicated by the alternate long and short dash line, and is provided in an intermediate portion of the adjacent bridges 24. Further, in the present embodiment, the shape of the concave groove 22b is such that the cross-sectional shape is a semi-oval shape (a shape obtained by dividing an oval in half).

  Next, the structure of the injection mold of the cap with TE band 20 and the injection molding method will be described with reference to FIGS. In FIG. 2, the main structure of the mold is a fixed cavity 11 having a gate 11a, a movable mold 14, a movable core 32 fitted to the movable mold 14, a fixed cavity 11 and a movable mold. It consists of a pair of slide cores 13 that slide left and right between the plates 14. The difference between the mold structure described here and the mold structure described in the background art is that the shape of the movable core is different, and the other components have the same shape.

  Between the movable side core 32 and the fixed side cavity 11, there is a vacant part D, and between the movable side core 32 and the pair of slide cores 13, there are vacant parts E, D. The molten resin injected from the gate 11a flows and fills along the resin flow Q indicated by the arrows in the order of the vacant space D → E → F. The TE band 22 is formed by the bridge 24 and the vacant part F.

  As shown in FIG. 3, the movable core 32 in this embodiment has a plurality of convex portions 32 a on the outer peripheral surface of the movable core 32 where the shape of the inner peripheral surface 22 a of the TE band 22 is formed (transferred). Provided. The convex portion 32a is provided at a position that is an intermediate portion between the adjacent bridges 24, and is the central axis of the core that forms the inner peripheral surface 22a of the TE band 22, that is, in this embodiment, the movable side core 32. It is provided in parallel with the central axis C. Further, in the present embodiment, the convex portion 32a is formed into a semi-circular convex shape with a semi-elliptical cross section, and the end surface portion 32b has a flat surface (enlarged). See perspective view).

  The pair of slide cores 13 has the same specifications as the slide core (see FIG. 7) in the background art described above. That is, as shown in FIG. 7, the pair of slide cores 13 has a molding portion 13a formed with a protruding portion 13b that circulates toward the center side, and is cut from a protruding tip surface 13d at the tip of the protruding portion 13b. A plurality of slits 13c are provided at regular intervals. Then, as shown in FIG. 2, the molten resin flows from the slit 13 c to the vacant portion F to form the TE band 22. Moreover, the vacant space E is formed by the slit 13c itself, and the bridge 24 is formed.

  Returning to FIG. 3, when the pair of slide cores 13 are clamped, the tip portions thereof, that is, the protruding tip surfaces 13 d of the protruding portions 13 b of the molding portion 13 a are in contact with the outer peripheral surface of the movable core 32. And the front-end | tip part of the protrusion part 13b of the shaping | molding part 13a is mounted on the end surface part 32b of the convex part 32a at that time, and the protrusion part 13b is supported by the convex part 32a (refer enlarged view).

  When molten resin is injected from the gate 11a under the above-described mold structure, the resin flows through the vacant portions D → E → F, and the cap body 21, the bridge 24, and the TE band 22 are formed. When the slide core 13 is opened when the mold is opened, a minute gap 23 is formed.

Next, the effect by providing the convex part 32a in the outer peripheral surface of the movable side core 32 is demonstrated. The surface without the slit 13c in the protruding portion 13b of the molding portion 13a of the slide core 13 receives the flow pressure of the molten resin to be filled. In particular, when the thickness t of the protrusion 13b is thin, deformation such as warpage occurs in the protrusion 13b due to the force of the fluid pressure. However, if the tip end portion of the protruding portion 13b is supported by the end surface portion 32b of the convex portion 32a provided on the movable side core 32, an action that resists the flow pressure of the resin is produced, and warping of the protruding portion 13b is generated. Can be suppressed. In addition, quality problems such as TE band galling caused by warping can be solved.
Moreover, since the site | part which receives the flow pressure of molten resin most is an intermediate site | part of the adjacent slit 13c, ie, the intermediate site | part of the adjacent bridge | bridging 24, the convex part 32a is provided in the location located in the intermediate site | part. And deformation such as warping can be effectively suppressed.
And the effect of the lifetime improvement and quality improvement of a metal mold | die can be acquired.

Moreover, in this embodiment, the end surface part 32b of the convex part 32a is made into semi-oval shape. With such a shape, the area for supporting the tip of the protruding portion 13b of the molded portion 13a is increased, and the supporting force is also increased.
However, in the present invention, the convex portion is not limited to the scalloped shape. For example, the same effect can be obtained even if the cross-sectional shape of the convex portion is a trapezoidal shape, a quadrangular shape, a semicircular shape, or the like.

Further, the convex portion 32 a is provided in parallel with the central axis C of the movable side core 32. If parallel, the releasability from the movable side core 32 of the cap 20 with the TE band is improved.
In the present embodiment, the shape of the inner peripheral surface of the cylindrical portion 21b of the cap body 21 and the inner peripheral surface 22a of the TE band 22 is formed by one movable-side core 32. It is also possible to construct with a plurality of cores of the mold. In such a case, a convex portion is formed on the core that forms the shape of the inner peripheral surface 22a of the TE band 22, and the convex portion is formed in parallel with the central axis of the core.

  When the injection molding method under the above-mentioned mold structure is taken, the cap 20 with the TE band shown in FIG. 1 is obtained. Here, the width and depth of the concave groove 22 b provided in the TE band 22, that is, the width and height of the convex portion 32 a provided in the movable side core 32 that is a mold are the support force of the protruding portion 13 b of the slide core 13. It is preferable to set the thickness appropriately in consideration of the strength, the releasability of the cap 20 with the TE band from the mold, and the locking property between the TE band 22 and the container opening.

  By providing a concave groove in the TE band of the cap with the TE band, as described above, the life of the mold is extended, and the quality of the cap can be improved.

1A and 1B are a plan view and a cross-sectional view schematically showing a cap with a TE band of the present invention, in which FIG. 1A is a plan view, FIG. 1B is a cross-sectional view along A-A in FIG. c) is a BB cross-sectional view in FIG. FIG. 2 is a cross-sectional view of an essential part schematically showing a molding die structure of a portion having a bridge of a cap with a TE band in FIG. 1. FIG. 2 is a cross-sectional view of an essential part schematically showing a molding die structure of a portion without a bridge of a cap with a TE band in FIG. 1. It is the top view (a) and sectional drawing (b, c) which showed typically the cap with a TE band in a prior art. FIG. 5 is a cross-sectional view of an essential part schematically showing a molding die structure of a portion having a bridge of a cap with a TE band in FIG. 4. FIG. 5 is a cross-sectional view of an essential part schematically showing a molding die structure of a portion without a bridge of the cap with a TE band in FIG. 4. It is the top view which showed typically the slide core in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Fixed side cavity 11a Gate 13 Slide core 13a Molding part 13b Projection part 13c Slit 13d Projection front end surface 14 Movable side plate 20 Cap with TE band 21 Cap body 21a Canopy part 21b Tube part 22 TE band 22a Inner peripheral surface 22b Concave groove 23 Minute gap 24 Bridge 32 Movable core 32a Convex part 32b End face part

Claims (4)

In a cap injection molding method in which a tamper-evidence band is integrally formed through a plurality of bridges in a minute gap at the lower end of the cap body,
A plurality of convex portions parallel to the central axis of the core for molding the inner peripheral surface shape of the tamper evidence band of the mold for molding the cap are provided at regular intervals, and the minute gap and the plurality of bridges An injection molding method for a cap, characterized in that a tip of a slide core for forming the shape of the mold is supported by an end surface of the convex portion, and the cap is molded by injecting molten resin into the cavity of the mold. .   2. The cap injection molding method according to claim 1, wherein the plurality of convex portions are provided so as to be positioned at intermediate positions of the adjacent bridges. In the cap formed by integrally molding the tamper evidence band through a plurality of bridges in the minute gap at the lower end of the cap body,
A cap characterized in that a plurality of concave grooves parallel to the central axis of the tamper evidence band are provided at regular intervals on the inner peripheral surface of the tamper evidence band.   The cap according to claim 3, wherein the plurality of concave grooves are provided at intermediate portions of the adjacent bridges.

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