JP3695870B2 - Synthetic resin plug injection molding method, mold used in the method, and synthetic resin plug manufactured by the method - Google Patents

Description

[0001]
[Field of the Invention]
The present invention relates to a method of injection molding of a synthetic resin plug that accommodates liquid, fine powder, etc., a mold used for the method, and a synthetic resin plug produced by the method.
[0002]
[Prior art]
In recent years, improvement and development of synthetic resins have progressed significantly, and various liquids and fine powders containing special chemicals can be accommodated. As a method of manufacturing such stoppers such as containers and glass containers, injection with synthetic resins is possible. Molding is frequently used.
This type of container is composed of a main body part and a plug part (lid body). The injection molding method for the plug is generally as shown in FIG. By using halved molds 3a ′ and 3b ′ having a split surface along the rotation axis direction of the rotating stopper 1 ′, as shown in FIG. 6, the halved mold 3a ′ is formed after injection molding. , 3b ′, and as shown in FIG. 7, a method of taking out the formed plug by ejecting in the axial direction P (the direction of the mouth) is used.
[0003]
[Problems to be solved by the invention]
The above-described injection molding method and mold structure are implemented for the purpose of making the structure and mold operation as simple as possible, and it can be said that the number of parts (number of mold divisions) is small and reasonable. There is a problem like this.
That is, even when the container body contains the liquid and is completely plugged (lid), the contained liquid leaks out during the transportation and handling.
[0004]
Therefore, the present inventor has examined and analyzed this problem from various angles, and as a result, in the sealing action between the mouth part and the stopper of the container, the peripheral part of the stopper 1 ', particularly the outer part responsible for the sealing action. It was found that this is caused by the formation of subtle irregularities on the peripheral portion 1c ′. Furthermore, when the unevenness | corrugation of this stopper 1 'was examined in detail, it discovered that this existed on the split surface of the half mold for shaping | molding along the axis line of stopper 1'.
In particular, there is a problem that unevenness becomes more and more remarkable due to aging of the mold due to long-term use.
Therefore, it has been concluded that this fine unevenness may impede the complete sealing action between the outer surface of the stopper and the sealing member at the mouth of the container.
[0005]
An object of the present invention is to provide a synthetic resin plug capable of solving such problems and exhibiting an excellent sealing effect.
[0006]
[Means for Solving the Problems]
The injection molding method of the synthetic resin plug according to the present invention is as follows.
An injection molding method of a synthetic resin plug that plugs into the mouth of a container with a screw-in type,
At least the seal portion 1c of the head portion 1a of the spigot 1 is formed by the annular mold 2,
A main body remaining portion 1b of the spigot 1 is formed by half molds 3a and 3b having split faces along the axial direction P of the spigot 1;
After injection molding, only the half molds 3a and 3b are slid in a direction orthogonal to the axial direction P of the plug 1;
The head 1a of the plug 1 is removed from the annular mold 2 by ejecting the plug 1 along the axial direction P toward the head.
I took the means.
The annular mold 2 may be molded to a portion other than the seal portion 1c shown in the embodiment, for example, to the vicinity of the head portion 1a depending on the shape of the plug 1.
[0007]
In the present invention, it is preferable to form the seal portion 1c formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward by the annular mold 2.
[0008]
The mold used for injection molding of the synthetic resin spigot according to the present invention is:
A mold used for injection molding of a synthetic resin spigot that plugs into the mouth of a container with a screw-in type,
An annular mold 2 configured to form at least the seal portion 1c of the head 1a of the spigot 1,
A half split metal having a split surface along the axial direction P of the plug 1 that forms the main body remaining portion 1b of the plug 1 and is slidable in a direction perpendicular to the axial direction P of the plug 1 Consists of molds 3a and 3b,
I took the means.
[0009]
In the present invention, it is preferable that the annular mold 2 is configured to form a seal portion 1c formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward. .
[0010]
In the present invention, it is preferable that the half molds 3a and 3b are configured so as to form the screw portion 1d of the head portion 1a of the spigot 1.
[0011]
The synthetic resin mouthpiece according to the present invention is manufactured by the method of claim 1 or claim 2.
[0012]
The half molds 3a and 3b referred to in the present invention constitute the main body remaining portion 1b excluding the head portion 1a of the spigot 1, but all of the lower end portion, the upper surface portion of the head portion and the like are half of these. For example, the lower end portion and the head upper surface portion may be separately formed by appropriate mold portions, and the present invention is not limited to the split molds 3a and 3b. Since the present invention relates to a method and a mold for improving the sealing effect, a molding method and a mold in which such a separate mold part is used together are also within the technical scope of the present invention.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
According to the present invention, the sealing portion 1c of the head 1a is formed by the annular mold 2 that is not half-divided, and the lower main body portion 1b is formed by the half-molding molds 3a and 3b. As a result, there is no micro unevenness formed on the seal portion 1c of the head portion 1a during molding, and therefore, it is fitted to the mouth of the container as shown in FIG. Sometimes a complete adhesion is obtained and an excellent sealing action can be exhibited.
[0014]
Depending on the manufacturing method of the present invention, the remaining half 1b of the main body 1b is not different from the conventional one in that the half molds 3a and 3b are slid in the direction perpendicular to the axis P, and the plug 1 Since the ejection is performed in the same direction as in the prior art, the plug 1 that exhibits the above-described excellent sealing action can be injection-molded in a state that does not require a special process as compared with the prior art.
[0015]
Incidentally, a minute projection 1e (annular) is formed between the screw portion 1d below the seal portion 1c of the plug 1 and this portion slightly forms an annular metal when the plug 1 is ejected. At this time, since the half-divided dies 3a and 3b have already escaped to both sides, even if the minute protrusion 1e is bent in the direction (downward) of the screw 1d (resin elasticity) ), There is a sufficient clearance, and therefore it can be removed from the annular mold 2 without difficulty.
[0016]
【Example】
A preferred embodiment of a method for injection molding of a synthetic resin plug according to the present invention, a mold used in the method, and a synthetic resin plug produced by the method will be described in detail below with reference to the drawings.
[0017]
As shown in FIG. 1, a mold used for an injection molding method of a synthetic resin spigot that plugs into a mouth portion of a container forms a seal portion 1 c of a head portion 1 a of the spigot 1. An annular mold 2 configured as described above, and a split surface along the axial direction P of the plug 1 that forms the main body remaining portion 1b of the plug 1, and is orthogonal to the axial direction P of the plug 1 It consists of half molds 3a and 3b configured to be slidable in the direction.
Here, the molds corresponding to the head 1a and the lower surface of the spigot 1 are not essential components of the present invention and are not described in detail because they are the same as in the prior art.
[0018]
The annular mold 2 is configured to form a seal portion 1c formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward. And the said half mold 3a * 3b is comprised so that the thread part 1d of the head 1a of the spigot 1 may be formed.
[0019]
The manufacturing method of the plug 1 is as follows:
(1) As shown in FIG. 1, a seal portion 1c of the head portion 1a of the spigot 1 is formed by the annular mold 2;
(2) A main body remaining portion 1b of the spigot 1 is formed by half molds 3a and 3b having split faces along the axial direction P of the spigot 1;
(3) As shown in FIG. 2, after injection molding, only the half molds 3a and 3b are slid in a direction perpendicular to the axial direction P of the plug 1;
(4) As shown in FIG. 3, the head 1a of the plug 1 is removed from the annular mold 2 by ejecting the plug 1 along the axial direction P toward the head.
This process is carried out.
[0020]
According to this method, the plug 1 having no minute unevenness due to the split mold is produced on the seal portion 1c of the head portion 1a of the plug 1. As shown in FIG. Thus, a tight sealing action (the seal portion is indicated by a broken-line circle) is obtained when the seal member 4 is fitted.
The annular mold 2 forms a seal portion 1c formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward.
Further, the operation steps of the mold corresponding to the head 1a and the lower surface of the plug 1 are not essential components of the present invention and are the same as those in the prior art, and thus detailed description thereof is omitted here.
[0021]
【The invention's effect】
According to the present invention, it is possible to completely eliminate the formation of subtle irregularities in the sealing part of the plug by the split mold, and it is possible to eliminate the gap between the outer surface of the plug and the sealing member for the mouth of the container. Thus, it has become possible to provide a mouth plug capable of providing a perfect sealing action and exhibiting an excellent sealing effect.
And it can be carried out with an extremely simple structure of separating the annular mold and the half mold, and since it is not necessary to slide the annular mold, it can be carried out without the need for complicated operating mechanisms and processes. .
[Brief description of the drawings]
FIG. 1 is a longitudinal side view showing one step of an injection molding method for a synthetic resin plug according to the present invention.
FIG. 2 is a longitudinal side view showing one step of a method for injection molding a synthetic resin plug according to the present invention.
FIG. 3 is a longitudinal side view showing one step of a method for injection molding a synthetic resin plug according to the present invention.
FIG. 4 is a partially enlarged longitudinal sectional side view of a synthetic resin plug according to the present invention.
FIG. 5 is a longitudinal side view showing one step of the injection molding method for a synthetic resin plug according to the prior art.
FIG. 6 is a longitudinal side view showing one step of a method for injection molding a synthetic resin plug according to the prior art.
FIG. 7 is a longitudinal side view showing one step of the injection molding method for a synthetic resin plug according to the prior art.
[Explanation of symbols]
1 Mouth 1a Head 1b Remaining body 1c Seal 1d Screw 2 Annular mold 3a Half mold 3b Half mold P Axial direction

Claims (6)

An injection molding method of a synthetic resin plug that plugs into the mouth of a container with a screw-in type,
At least the seal portion 1c of the head portion 1a of the spigot 1 is formed by the annular mold 2,
A main body remaining portion 1b of the spigot 1 is formed by half molds 3a and 3b having split faces along the axial direction P of the spigot 1;
After injection molding, only the half molds 3a and 3b are slid in a direction orthogonal to the axial direction P of the plug 1;
The head 1a of the plug 1 is removed from the annular mold 2 by ejecting the plug 1 along the axial direction P toward the head.
A method for injection molding of synthetic resin plugs. The annular mold 2 forms a seal portion 1c that is formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward.
A method for injection molding a synthetic resin spigot according to claim 1. A mold used for injection molding of a synthetic resin spigot that plugs into the mouth of a container with a screw-in type,
An annular mold 2 configured to form at least the seal portion 1c of the head 1a of the spigot 1,
A half split metal having a split surface along the axial direction P of the plug 1 that forms the main body remaining portion 1b of the plug 1 and is slidable in a direction perpendicular to the axial direction P of the plug 1 Consists of molds 3a and 3b,
Mold used for injection molding of synthetic resin plugs. The annular mold 2 is configured to form a seal portion 1c formed from the upper surface of the head portion 1a of the spigot 1 to the lower surface of the outer peripheral edge directed downward.
A mold used for injection molding of the synthetic resin spigot according to claim 3. The halved molds 3a and 3b are configured to form a threaded portion 1d of the head 1a of the spigot 1.
A mold used for injection molding of the synthetic resin spigot according to claim 3 or 4. A synthetic resin plug produced by the method according to claim 1 or 2.

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