JP2013169978A - Cap with gasket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tightly-sealed cap with a gasket.SOLUTION: A cap 4 with a gasket includes a cap body 1 having a screw thread 1d, and is configured in such a manner that a gasket 2 formed of a resin different from that of the cap body 1 is formed on the rear surface of the top plate 1a of the cap body 1, a corner R-surface on the lower surface side of the screw thread 1d forms an R-surface larger than the corner R-surface on the upper surface side of the screw thread 1d, and a gap is formed between the outer peripheral wall of the gasket 2 and the rear surface of a sidewall 1b of the cap body 1 near the top plate 1a.

Description

The present invention relates to a highly airtight cap that is attached to the mouth of a container such as a glass bottle or a plastic bottle containing a liquid such as soy sauce.

  The packing described in Patent Document 1 has been proposed as a means for tightly sealing the mouthpiece opening in a relatively large vertical displacement range with the screw cap assembly with the screw cap assembly. In the packing of Patent Document 1, the lower end outer diameter is set to a value smaller than the upper end opening diameter of the casing mouth tube from the base plate forming the assembly part to the cap, and the upper end outer diameter is set to the casing mouth tube. An inverted frusto-conical cylinder-shaped seal cylinder set to a value larger than the upper end opening diameter of the cylinder is suspended and pressed between the top plate of the cap and the upper end surface of the casing mouth cylinder to be elastically deformed. There has been an invention in which the upper end surface of the mouthpiece is in close contact with the upper surface of the mouthpiece by deformation and the mouthpiece is hermetically held.

  As a manufacturing method of a cap with packing capable of reliably sealing the container, a cap with packing and a manufacturing method thereof of Patent Document 2 have been proposed. In the cap with packing and the manufacturing method thereof in Patent Document 2, a cavity for storing packing is formed on the inner ceiling surface of the cap body, and the cavity is melted at the time of fusing with the cap body. In order not to flow out to the outside, an invention has been made in which the inner ceiling surface is recessed deeper than the thickness of the packing.

Japanese Utility Model Publication No. S59-143953 Japanese Patent Laid-Open No. 10-120015

  Even if the cap is fitted into the container, the contents may leak out from the gap between the container and the cap when the liquid in the contents is highly permeable vinegar or soy sauce. In view of this, many are used which can maintain a sealing property by fitting a packing made of a rubber material or the like into a place where the container and the cap are fitted. The packing of Patent Document 1 tightly seals the mouth opening in a relatively large vertical displacement range with a screw cap assembly with respect to the case cap of the screw cap. The packing is attached to the back of the top plate of the cap. Since the fitting tube is fitted into the formed fitting cylinder, there is a problem that the packing made of a soft elastic material is detached while repeatedly opening and closing the cap. In addition, in order to obtain a structure that obtains the amount of elastic deformation along the vertical direction, the seal cylinder has an inverted frustoconical cylinder shape, so when trying to press down the opening of the container with packing, Since the end of the seal tube is bent inward, the force for tightly pressing the opening of the container with the packing remains weak, and it is difficult to say that it has a high sealing function.

Therefore, in order to prevent the detachment of the packing, a packing made of a soft elastic material such as an elastomer is molded in advance, and the packing is formed by inserting the packing into the inner ceiling surface of the cap body. Is described in Patent Document 2. As described in the prior art of Patent Document 2, when a packing formed of a soft elastic material such as an elastomer is used as an insert so as to be integrated with the cap body, the packing is thermally fused to the cap body. At this time, the packing that has started to melt due to high heat flows out, and deformation and burrs occur. Therefore, if the filling pressure is lowered in order to suppress deformation and burrs, the cap body suffers from sink marks and shorts. Therefore, Patent Document 2 is an invention in which the inner ceiling surface of the cap body is recessed deeper than the thickness of the packing so as not to flow out the packing resin melted in the screw thread. Even if it is a cap with a packing, it is formed in a state where the packing is deformed because there is no change in that the previously formed packing is melted with high heat by insert molding. However, since the packing described in Patent Document 2 is a plate type, even if the packing starts to melt, the plate type packing only flows into the recess, so the deformation state is difficult to understand. When insert-molding a packing that protrudes to the lower end as shown above, the packing melts and part of the cap body resin mixes and deforms, as well as burrs. Therefore, it is very difficult to produce a good packing cap with no burr or deformation as well as a reduced function as a packing.

  An object of the present invention is to solve the above problems and provide a highly sealed cap with packing.

  A cap with packing made of a synthetic resin material having a thread on the cap body for sealing the container opening, and projecting annularly downward on the back surface of the top plate portion of the cap body, with a resin different from the cap body In addition to forming the molded packing, the lower corner R surface facing the screw tip forms a larger R surface than the upper corner R surface facing the screw tip, and the outer peripheral wall of the packing and the ceiling It is a cap with packing which provided the clearance gap between the cap side wall part back surface near the board part.

  It is a cap with packing which becomes narrow as the cross-sectional width of the said packing goes to a lower end.

  It is a cap with packing which formed the holding | maintenance part which protruded cyclically | annularly below along the inner peripheral wall of packing at a part of top plate part back surface of the said cap main body of the welding surface which the said cap main body and packing contact.

  After the cap body is formed and removed from the primary mold, the cap body is inserted into the secondary mold, and then the secondary cavity mold and the secondary core mold abut against each other, and the packing is integrally formed with the cap body. It is a cap.

  The said secondary core type | mold is a cap with the packing formed which is a secondary type | mold which has a cylindrical guide surface along the screw thread front end of a cap main body.

  The guide tip portion of the guide surface is a cap with packing formed so as to abut on the back surface of the cap body top plate portion.

  The present invention is a cap with packing made of a synthetic resin material having a screw thread on a cap body for sealing a container opening, and protrudes annularly downward on the back surface of the top plate portion of the cap body. And a lower corner R surface facing the thread tip is larger than an upper corner R surface facing the thread tip, and the outer periphery of the packing is formed. Since the cap is provided with a gap between the wall and the back surface of the side wall portion of the cap body in the vicinity of the top plate portion, the packing has a shape projecting to the specified circumferential area on the back surface of the top plate portion of the cap body. Can be formed without causing deformation or burrs. As a result, soft elastic materials such as elastomers used to form the packing are expensive compared to resins such as polypropylene used when molding cap bodies, etc. A small amount of a highly sealed cap with packing can be formed and provided.

Since the present invention is a cap with packing that becomes narrower as the cross-sectional width of the packing is toward the lower end, when the container and the cap with packing are set, the packing is in close contact with the inside of the container opening. In order to prevent the packing from being bent to the inside by the opening of the container and weakening the adhesion, the taper becomes narrower as the cross-sectional width of the packing becomes narrower toward the lower end. The cap with packing which can hold | maintain property can be provided.

The present invention provides a cap with packing in which a holding portion protruding annularly downward is formed on a part of the back surface of the top plate portion of the cap main body on the welding surface where the cap main body and the packing are in contact with each other along the inner peripheral wall of the packing. Therefore, in order to prevent the packing from being pushed inward by the opening of the container and bending to weaken the adhesive force, forming the holding part can suppress the packing from being bent inward and maintain the sealing property. The cap with packing which can be provided can be provided.

In the present invention, the cap body is formed and removed from the primary mold, the cap body is inserted into the secondary mold, and then the secondary cavity mold and the secondary core mold are abutted so that the packing is integrated with the cap body. Because it is a cap with packing formed, packing made of resin such as elastomer, which is softer than the cap body molded with olefinic thermoplastic resin such as polypropylene, inserts a hard material and softens later Forming the direction of the material can provide a cap with packing that does not cause deformation or burrs.

Since the secondary core mold of the present invention is a cap with packing formed as a secondary mold having a cylindrical guide surface along the thread tip of the cap body, the thread is formed on the inner side of the cap body. Even if it is a cap body, the secondary cavity mold and the secondary core mold are clamped while the guide surface of the secondary core mold is along the tip of the screw thread. The cap with packing which can be formed in the back surface of a top-plate part can be provided.

In the present invention, the guide tip portion of the guide surface is a cap with packing formed to abut on the back surface of the cap body top plate portion, and thus protrudes to a specified small circumferential area on the back surface of the top plate portion of the cap body. The shaped packing can be formed without causing deformation or burrs. In addition, even if the resin of the cap body on the welding surface is about to melt due to the heat of fusion of the packing, the packing is formed with the guide tip part being in contact with the back surface of the cap body top plate part. A cap with good quality packing can be provided without worrying about deforming the side wall surface or the thread on the back surface.

It is a perspective view of a cap section with packing which shows an embodiment of the present invention. It is sectional drawing of FIG. It is sectional drawing which shows the shaping | molding method 1 which is embodiment of this invention. It is sectional drawing which shows the shaping | molding method 2 of the embodiment. It is sectional drawing which shows the shaping | molding method 3 of the embodiment. It is sectional drawing which shows the shaping | molding method 4 of the embodiment. It is sectional drawing which shows the shaping | molding method 5 of the embodiment. It is sectional drawing to which the a part of FIG. 7 was expanded. It is sectional drawing which shows the shaping | molding method 6 of the embodiment. It is sectional drawing to which the b part of FIG. 9 was expanded. It is sectional drawing which shows the shaping | molding method 7 of the embodiment. It is sectional drawing which shows the shaping | molding method 8 of the embodiment. It is a top view of the state which set the cap which shows embodiment of this invention to the container. It is sectional drawing which shows the state which cut | disconnected FIG. 13 in the zz direction. It is sectional drawing to which the c section of FIG. 14 was expanded.

1 and 2, the present invention is a cap 4 with packing for sealing an opening of a container containing a highly permeable content such as soy sauce, vinegar, or a chemical liquid. The cap 4 with packing of the present invention includes a cap body 1 made of a synthetic resin material such as polypropylene having an annular thread 1d formed on a side wall 1b on the back surface of the cap body 1, and a top plate portion 1a of the cap body 1. It is the cap 4 with packing which consists of the packing 2 integrally molded by the back surface. On the side wall 1b of the cap body 1, rib portions 1c having a non-slip function for easily assisting the opening and closing of the container and the cap body 1 are arranged at appropriate intervals in the vertical direction on the outer peripheral side wall surface of the side wall 1b. A rib portion 1c protruding in a substantially semi-cylindrical shape is formed. The upper end side of the rib portion 1c is rounded so that fingers do not hurt when opening and closing.

As shown in FIGS. 1 and 2, a ring-shaped packing 2 that protrudes downward and has an annular shape on the back surface of the top plate portion 1 a of the cap body 1 has a soft elasticity such as a resin different from the cap body 1, such as an elastomer. Made of material. Further, as shown in FIG. 2, a space portion 3 is formed between the outer peripheral wall of the packing 2 and the back surface of the side wall portion 1b of the cap body 1 near the top plate portion 1a. Since soft elastic materials such as elastomers are expensive compared to synthetic resin materials such as polypropylene used for the cap body 1, it is possible to form an effective packing 2 with a small amount of use, thereby reducing costs. It is a cap 4 with packing which can be done.

Further, as shown in FIG. 2, the packing 2 has an inner taper 2a and an outer taper 2b that become narrower in cross-sectional width toward the lower end. FIG. 13 is a plan view of the state in which FIG. 13 is fitted to the container 5 with the cap 4 with packing according to the present invention, and FIG. 14 is a cross-sectional view showing the state of FIG. 15 is an enlarged cross-sectional view of a portion c in FIG. 14. As shown in FIGS. 13 to 15, the inclination of the outer taper 2b is an inclination for smoothly fitting the opening of the container 5. Is provided. Further, when the cap 4 with packing is set in the container 5, when the packing 2 comes into close contact with the inside of the opening of the container 5, the packing 2 is pushed by the opening of the container 5, and is bent inward so that the adhesive force is increased. In order to prevent weakening, the outer taper 2b and the inner taper 2a are tapered so that the cross-sectional width becomes narrower toward the lower end, so that the inclination of the inner taper 2a prevents the packing 2 from bending. It is possible to maintain hermeticity.

Further, as shown in FIGS. 13 to 15, a substantially U-shaped protruding holding portion 1 e that is annularly ring-shaped downward is provided near the inner taper 2 a of the welding surface where the cap body 1 and the packing 2 are in contact with each other. It is formed on the back surface of the cap body 1. The holding portion 1e is formed shorter than the downward protrusion of the packing 2, and the inner side surface of the holding portion 1e has the same inclination as the inner taper 2a, and the inner side surface of the holding portion 1e and the inner taper 2a The faces are connected. Accordingly, the holding portion 1e is a reinforcing portion provided to prevent the packing 2 from being pushed inward when the packing 2 is pushed into the opening of the container 5, so that the packing 2 is bent. Further, it is possible to provide a cap 4 with packing that can prevent the above-described problem and maintain high sealing performance. Further, since the holding portion 1e is formed as the cap body 1, as a result, the resin used in the packing 2 can be further cut, and the cost can be reduced.

3 to 12, a method for forming the cap 4 with packing according to the present invention will be described. 3 to 5 show a primary mold A for forming the cap body 1. A primary mold A1, a primary core mold A2, and a stripper A3 constitute a pair of primary molds A. The primary mold A1 is provided with an injection unit A1a that melts at a high temperature of the synthetic resin and an injection part A1b that is connected to the injection unit A1a and flows out the synthetic resin material. In FIG. 3, the mold is clamped by the primary cavity mold A1, the primary core mold A2 and the stripper A3 abutting, and the product shape, that is, the cap body 1 is formed by the mold surface of the primary mold A1 and the mold surface of the primary core mold A2. It is formed. A synthetic resin material melted at a high temperature is injected into the injector A1a from the injection portion A1b at a high pressure, and the cap body 1 is molded. After the cap body 1 is cured, the primary mold A1 is retracted from the primary core mold A2 as shown in FIG. 4 and the primary mold A mold is opened, and then the screw of the primary core mold A2 is opened as shown in FIG. The cap body 1 is taken out by rotating.

6 to 12 show a secondary mold B for forming the packing 2. The secondary cavity mold B1, the secondary core mold B2, and the stripper B3 constitute a pair of secondary mold B molds. The secondary core mold B2 is provided with an injector B2a that melts at a high temperature of the synthetic resin and an injection portion B2b that is connected to the injector B2a and flows out of the synthetic resin material. As shown in FIG. 6, the cap body 1 previously molded with the primary mold A is inserted and set into the secondary mold B1. At this time, the secondary cavity mold B1 is formed such that the diameter of the inlet B1a to be inserted is larger than the diameter of the outer peripheral surface of the cap body 1 so that the cap body 1 can be easily set. Therefore, even if it is the cap main body 1 which formed the rib part 1c which protruded outward in the side wall part 1b, when inserting in the said secondary cavity type | mold B1, it is a metal mold | die which can be set without positioning.

  Further, as shown in FIGS. 6 to 10, the secondary cabinet mold B1, the secondary core mold B2, and the stripper B3 are brought into contact with each other, the mold is clamped, and set in the mold surface of the secondary cabinet mold B1. The packing 2 is formed as shown in FIG. 11 by the back surface of the top plate portion 1a of the cap body 1 and the mold surface of the secondary core mold B2. A synthetic resin material melted at a high temperature is injected into the injector B2a from the injection part B2b at a high pressure, and the packing 2 is molded while being welded to the back surface of the top plate part 1a of the cap body 1. After the packing 2 is cured on the back surface of the top plate 1a, the secondary mold B1 is retracted from the secondary core mold B2 to open the mold of the secondary mold B as shown in FIG. 12, and then the stripper B3 is opened. The cap 4 with packing pushed out at is taken out.

FIG. 7 is a cross-sectional view showing the progress of the secondary core mold B2 colliding with the secondary mold B1, and FIG. 8 is an enlarged cross-sectional view of a part of FIG. As shown in FIG. 2, when the secondary core mold B2 collides with the secondary mold B1, the guide surface that abuts along the tip of the thread 1d of the cap body 1 set in the mold surface of the mold B1. B2c is formed in the secondary core type B2. Since the guide B2c surface has a cylindrical shape, the cap main body 1 having a large rib portion 1c as shown in FIG. 1 provided to facilitate opening when the side wall 1b of the cap main body 1 is opened. Even when the cap body 1 is inserted into the secondary mold B, it is not necessary to position the rotation by the outward projection of the rib portion 1c, so the cap body 1 can be easily inserted into the secondary mold mold B1. Thus, molding can be started. Therefore, the rib portion 1c can be easily formed by the cap body 1 having a shape in which the rib portion 1c is formed thicker than the thickness of the side wall portion 1b including the thread 1d where the rib portion 1c is not formed. In addition, a highly sealed cap 4 with packing can be provided.

Also, as shown in FIG. 8, in order to make it easier for the guide B2c to enter along the tip of the screw thread 1d, the lower corner R surface facing the screw thread 1d tip faces the screw thread 1d tip. An R surface larger than the corner R surface on the upper surface side is formed. As a result, the secondary cavity mold B1 and the secondary core mold B2 can smoothly face each other.

9 shows a state in which the secondary cavity mold B1, the secondary core mold B2, and the stripper B3 are clamped after the cap body 1 is inserted into the secondary cavity mold B1, and FIG. FIG. As shown in FIGS. 9 and 10, when the secondary cabinet mold B1, the secondary core mold B2, and the stripper B3 are clamped, the guide tip B2d of the guide B2c surface is the back surface of the top plate 1a. At rest. Next, as shown in FIG. 11, the synthetic resin material melted at a high temperature in the injector B2a is injected to the injection portion B2b with a high pressure, and the packing 2 is attached to the back surface of the top plate portion 1a of the cap body 1 and the holding portion 1e. It is molded while being welded to the lower end surface.

The synthetic resin such as an elastomer used for the packing 2 is a soft resin material as compared with an olefin-based thermoplastic resin such as polypropylene forming the cap body 1. In this way, when forming a product using two different synthetic resins, insert a molding member of a soft resin material into a mold, and then inject a hard resin material to mold the remaining part, The soft resin material melts at a lower heat than the hard resin material, so that the member molded with the soft resin material melts by the heat of fusion of the hard resin material and flows into the part that must be molded with the hard resin material. It becomes a state. Therefore, there is a high possibility that a product that does not achieve its function will be produced, and the occurrence of deformation and burrs will increase. However, the cap 4 with packing according to the present invention is formed by using the hard resin material in the primary mold A as shown in FIG. 3 to FIG. First, the cap body 1 molded before is inserted, and then the packing 2 is molded with a soft resin material as shown in FIG. 9 to FIG. It is possible to provide the cap 4 with packing which does not flow and does not generate deformation or burrs.

Accordingly, the packing 2 that becomes narrower as the cross-sectional width goes toward the lower end is deformed or burrs generated while protruding downward as shown in FIG. 2 on the specified welding surface on the back surface of the top plate portion 1a of the cap body 1. Good products can be formed without Furthermore, even if the resin of the cap body 1 on the welding surface is about to melt due to the heat of fusion of the packing 2, as shown in FIGS. 9 and 10, the guide tip B2d becomes a wall during molding, The molten resin does not flow into the back surface of the side wall portion 1b or the screw thread 1d due to the heat of fusion. Thereby, the high-quality cap 4 with a packing can be provided with a small amount of resin used for the packing 2. Since soft elastic materials such as elastomer are expensive compared to synthetic resin materials such as polypropylene used for the cap body 1, an effective packing 2 can be formed with a small amount of use, and the cost can be reduced. The cap 4 with packing which can be provided can be provided.

DESCRIPTION OF SYMBOLS 1 Cap main body 1a Top plate part 1b Side wall part 1c Rib part 1d Screw thread 1e Holding part 2 Packing 2a Inner taper 2b Outer taper 3 Space part 4 Cap with packing 5 Container A Primary type A1 Primary mold type A1a Injector A1b Injection part A2 Primary core type A3 Stripper B Secondary type B1 Secondary cavity type B1a Entrance B2 Secondary core type B3 Stripper B2a Injector B2b Injection part B2c Guide surface B2d Guide tip

Claims (6)

A cap with packing made of a synthetic resin material having a thread on the cap body for sealing the container opening,
On the back of the top plate portion of the cap body, the ring protrudes downward and forms a packing formed of a resin different from the cap body,
The lower corner R surface facing the screw tip forms a larger R surface than the upper corner R surface facing the screw tip,
A cap with packing, characterized in that a gap is provided between the outer peripheral wall of the packing and the back of the side wall of the cap body in the vicinity of the top plate.   The cap with packing according to claim 1, wherein a cross-sectional width of the packing becomes narrower toward a lower end.   The holding portion that protrudes annularly downward is formed so as to be along the inner peripheral wall of the packing on a part of the back surface of the top plate portion of the cap main body on the welding surface where the cap main body and the packing are in contact with each other. The cap with packing as described in 1 and 2.   Forming and removing the cap body with the primary mold, inserting the cap body into the secondary mold, and then forming the packing integrally with the cap body by the secondary cavity mold and the secondary core mold abutting each other. The cap with packing according to any one of claims 1 to 3.   5. The cap with packing according to claim 1, wherein the secondary core mold is a secondary mold having a cylindrical guide surface along a screw thread tip of a cap body.   The cap with packing according to any one of claims 1 to 5, wherein a guide tip portion of the guide surface abuts on a back surface of the cap main body top plate portion.