JP2591131Y2 - Injection mold - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold for molding a bottomed container.

[0002]

2. Description of the Related Art Conventionally, a mold for injection-molding a bottomed container such as a plastic blood collection tube is disclosed in
As described in JP-A-65762 and JP-A-1-202417, a joining surface between a movable mold and a fixed-side mold plate is provided along the circumferential direction outside the open end surface of a bottomed container to be molded. There are things.

However, when a bottomed container is actually molded using this mold, the contact area between the molded product and the mold surface is reduced.
Since the fixed plate is larger than the movable mold, when the mold is opened, the molded product remains in the fixed mold, which hinders continuous molding.

[0004] As a countermeasure for this, it is conceivable to use a mold having an extremely tapered die surface.
Since an extreme slope is formed on the outer peripheral surface of the molded product, the appearance is poor and the product value is reduced. Further, there is a problem that the arrangement becomes complicated if a gap is formed in the box packing or if the packing is performed so that the gap is not formed.

A bottomed container formed at the time of opening the mold is provided with a concave portion of 0.1 to 0.2 mm in the mold surface of the movable die, and a resin portion is formed in the concave portion to form a convex portion. There has been proposed a method of attaching to a movable mold. However, the convex portion formed on the inner surface of the bottomed container is unnecessary and hinders use.

Further, in any of the above cases, burrs are easily generated along the circumferential direction outside the open end surface of the molded bottomed container, so that the bottomed container needs to be plugged. When used, there is a problem that when the stopper is opened, the finger touches the burr to easily tear the finger.

[0007]

SUMMARY OF THE INVENTION The present invention solves the conventional problems as described above, and forms an extreme slope on the outer peripheral surface of the bottomed container or forms a convex portion on the inner peripheral surface. An object of the present invention is to provide an injection molding die for molding a bottomed container, which can be taken out of a fixed mold without leaving the bottomed container attached to a movable mold when the mold is opened.

[0008]

According to the present invention, a movable core is provided.
And movable stripper plate
An injection mold having a cavity corresponding to the shape of a bottomed container to be formed between a core and a projecting stripper plate and a fixed side mold plate, wherein the movable mold projects when the mold is closed. The joint surface between the stripper plate and the fixed-side mold plate is disposed along the circumferential direction at an intermediate position of the outer peripheral surface of the bottomed container to be molded, and on the inner peripheral surface of the bottomed container to be molded. In the surface area (S1) of the corresponding movable core ,
Movable mold protrusion corresponding to the outer peripheral surface of the bottomed container to be molded
To which the surface area (S2) of the stripper plate is added
(S1 + S2) and the ratio of the surface area of the fixed die plate corresponding to the outer peripheral surface of the bottomed container to be molded (S3) [(S1 + S
2) / S3] is 1.05 or more.

In the present invention, the bottomed container is, for example, a wall having a thickness of 0.5 to 2 mm and a total length of 200 mm or less.
Examples include a reduced-pressure blood collection tube, a container, a cover, a housing, a drawer, and a box.

In the present invention, as the resin, all resins used for injection molding can be used, and examples thereof include polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene-styrene copolymer, polymethyl methacrylate, and polyamide.

First, an example of the injection mold according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway sectional view showing an example of the injection mold according to the present invention. Reference numeral 1 denotes an injection mold for manufacturing a bottomed container such as a blood collection tube to be molded, and includes a movable mold 11 and a fixed mold plate 12.

The movable mold 11 includes a core 111, a receiving plate 112, and a projecting stripper plate 113. still,
The core 111 and the receiving plate 112 may have an integral structure.
No.

The core 111 has a slender column at the tip and the center, a tip forming a portion forming the inner surface of a molded article to be formed, and a top formed as a hemispherical convex spherical surface. The central portion of the core 111 is inserted into a hole 113a formed in the projecting stripper plate 113. The diameter of the hole 113a on the side of the fixed mold plate 12 is enlarged to form an enlarged diameter portion 113b. Incidentally, the tip portion of the core 111 may be formed as a tapered surface with a diameter of 10/1000 or less which gradually narrows as its outer surface goes to the top.

The enlarged diameter portion 113b also functions as an opening end surface of the bottomed container to be molded and a cavity surface forming an outer peripheral surface of the opening end portion.
The base end of the core 111 has a diameter larger than that of the distal end portion and the central portion, and is fitted and fixed in a hole 112 a formed in the receiving plate 112. The core 111 is fixed to the movable mounting plate 15 via the receiving plate 112.

The fixed mold plate 12 is provided with a through hole 121 which forms the outer peripheral surface of the bottomed container to be formed. The fixed side mold plate 12 is provided with a gate 122 at a position corresponding to the top of the convex spherical surface at the top of the core 111.

Fixed-side template 12 and fixed-side template mounting plate 16
A runner stripper plate 18 and a runner / gate connecting plate 19 are provided between them.

The runner stripper plate 18 includes
A runner 181 and a sprue 182 are provided.
The runner / gate connecting plate 19 is provided with a runner 191 that connects the runner 181 and the gate 122.

When the mold is opened, the core 111 and the fixed mold plate 12
Between the core 111 and the stripper plate 113 for protrusion
Between the fixed side template 12 and the runner / gate connecting plate 19
During this time, the space between the runner / gate connecting plate 19 and the runner stripper plate 18 is opened, and the pressure between the runner stripper plate 18 and the fixed side mold plate mounting plate 16 is released, and the free state is established.

At the time of mold clamping, the outer peripheral surface of the tip of the core 111,
The cavity 20 that forms the bottomed container to be molded is formed by the stripper plate 113 for protrusion and the wall surface of the through-hole 121 of the fixed-side mold plate 12. Then, the sprue 1 is supplied from the gate 122 by an injection molding machine (not shown).
The molten resin supplied through 82 and the runners 181 and 191 is injected into the cavity 20 to form a bottomed container.

FIG. 2 is a sectional view showing a main part of the present invention. In the present invention, since the projecting stripper plate 113 of the movable mold 11 is provided with the enlarged diameter portion 113b, the joint surface between the projecting stripper plate 113 of the movable mold 11 and the fixed mold plate 12 when the mold is closed. The (parting surface) is disposed along the circumferential direction at a position on the opening end side of the outer peripheral surface of the bottomed container to be molded.

In the present invention, the surface area (S ₁ ) of the core 111 of the movable mold 11 corresponding to the inner peripheral surface of the bottomed container to be molded is provided on the movable surface corresponding to the outer peripheral surface of the bottomed container to be molded. The protruding stripper plate 113 of the mold 11 has a surface area (S ₂ ) of the inner peripheral wall of the enlarged diameter portion 113b added (S ₁ + S ₂ ) and a fixed-side mold corresponding to the outer peripheral surface of the bottomed container to be molded. The ratio with respect to the surface area (S ₃ ) of the plate 12 is 1.
The ratio is preferably in the range of 1.05 to 1.3.

Each of the above S _{1 to} S ₃ corresponds to a portion of the bottomed container to be molded at the time of opening the mold, where the sheared peeling force acts on the bottomed container. Accordingly, the portion where the projecting stripper plate 113 adheres to the opening end face of the bottomed container to be molded is substantially orthogonal to the mold opening direction, and when the mold is opened, the molded bottomed container is fixed to the fixed side. Since it does not contribute as a force for preventing it from being left in the template 12, it is excluded here.

If the ratio is less than 1.05, the molded bottomed container may be left in the fixed mold plate 12 when the mold is opened. The larger the ratio is, the less the danger of the molded bottomed container being left in the fixed side mold plate 12 at the time of opening the mold is eliminated.
Since the resistance at the time of operating and pushing out 13 increases, 1.
It is not very advisable to set it above 3.

In the injection mold according to the present invention, the joint surface between the movable stripper's projecting stripper plate and the fixed mold plate at the time of closing the mold is formed in a circumferential direction at an intermediate position of the outer peripheral surface of the bottomed container to be molded. And the protrusion of the movable mold corresponding to the outer peripheral surface of the bottomed container to be molded is provided on the surface area (S1) of the movable mold core corresponding to the inner peripheral surface of the bottomed container to be molded. for
Plus the surface area of the stripper plate (S2) and (S1 + S2), the ratio of the surface area of the fixed die plate corresponding to the outer peripheral surface of the bottomed container to be molded (S3) [(S1 + S
2) / S3] is 1.05 or more, so that the area of adhesion of the bottomed container to the mold surface on which the shearing force is applied when the mold is opened is increased by the above ratio and the mold surface Is the same per unit area for both the movable mold and the fixed mold, so the adhesive force of the bottomed container is larger for the movable mold than for the fixed mold, and the open mold is opened. Occasionally, the bottomed container can be taken out in a state in which it is securely attached to the movable mold without leaving it on the fixed mold plate. As a bottomed container, a bottomed container without a flange at the mouth
Even if it is a container, it can be reliably moved without leaving it on the fixed mold plate.
It can be taken out in a state where it is adhered to.

As a result, the bottomed container obtained has an excellent outer appearance because there is no extreme gradient on the outer peripheral surface or a convex portion on the inner peripheral surface, and can be easily packed in a box. Since no burrs are generated along the circumferential direction on the outside of the device, even when the plug is used for plugging, the finger does not touch the burr when the plug is opened and the finger is not torn.

[0026]

Embodiments of the present invention will be described below. Example 1 Using a mold for injection molding (16 holes) shown in FIGS. 1 and 2, a J # 220 type injection molding machine manufactured by Japan Steel Works, and polyethylene terephthalate (Mitsui Pet Co., Ltd.) as a resin.
Using a trade name "J001"), at a resin temperature of 300 ° C. and a cycle time of 30 seconds, 24 hours continuously, as shown in FIG. 3, the outer diameter of the opening end (R ₁ ) is 25 mm, and the outer diameter of the bottom is (R ₂ )
24 mm, length (L ₁ ) 75 mm, wall thickness (W) 1.5 m
Injection molding of a m-tube test bottomed container was performed.

When the mold is closed, the joint surface (P ₁ ) between the projecting stripper plate 113 of the movable mold 11 and the fixed mold plate 12 is 7 mm from the opening edge of the outer peripheral surface of the bottomed container to be molded. It was arranged along the circumferential direction at the position. still,
(S ₁ + S ₂ ) / S ₃ = 5.63 / 5.34 = 1.0
54.

As a result, at the time of molding, the molded bottomed container did not remain in the fixed mold plate 12, and a long continuous molding could be performed in a stable state.

COMPARATIVE EXAMPLE 1 A projecting stripper plate 113 has an enlarged diameter portion 113
Without providing b, the joint surface between the projecting stripper plate 113 of the movable mold 11 and the fixed-side mold plate 12 at the time of closing the mold so as to extend along the opening edge of the outer peripheral surface of the bottomed container to be molded in the circumferential direction. Injection molding of a bottomed container was performed in the same manner as in Example 1 except that the injection molding die provided in Example 1 was used.

The surface area (S ₁ ) of the movable mold corresponding to the inner peripheral surface of the bottomed container to be molded and the surface area (S ₃ ) of the fixed mold plate corresponding to the outer peripheral surface of the bottomed container to be molded. (S ₁ / S ₃ ) was 0.86.

As a result, at the time of molding, the molded bottomed container was clogged in the fixed side mold plate 12, and continuous production could not be performed.

Example 2 Except for the shape of the cavity, the same injection molding die (eight-cavity) as shown in FIGS. 1 and 2 was used.
Using a 0-ton injection molding machine, polycarbonate (trade name "L-1250" manufactured by Teijin Chemicals Ltd.) as a resin, resin temperature of 310 ° C., cycle time of 45 seconds, and continuous 24 hours as shown in FIG. , Opening end outside diameter (R ₃ ) 20m
m, bottom outer diameter (R ₄ ) 19.5 mm, length (L ₂ ) 40
A square bottomed container having a thickness of 2.0 mm and a wall thickness (W ₂ ) of 2.0 mm was injection molded.

When the movable mold 11 is closed, the joint surface (P ₂ ) between the projecting stripper plate 113 and the fixed mold plate 12 is 7 mm from the opening edge of the outer peripheral surface of the bottomed container to be molded. It was arranged along the circumferential direction at the position. still,
(S ₁ + S ₂ ) / S ₃ = 5.63 / 5.34 = 1.0
54.

As a result, at the time of molding, the molded bottomed container did not remain in the fixed-side mold plate 12, and a long-time continuous molding could be performed in a stable state.

COMPARATIVE EXAMPLE 2 The joining surface of the movable die 11 between the projecting stripper plate 113 and the fixed-side mold plate 12 when the mold is closed is provided without forming an enlarged diameter portion on the projecting stripper plate 113. Injection of a bottomed container similar to that of Example 2 was performed in the same manner as in Example 2, except that an injection molding die arranged along the circumferential direction at the opening edge of the outer peripheral surface of the bottom container was used. Molding was performed.

The surface area (S ₁ ) of the movable mold corresponding to the inner peripheral surface of the bottomed container to be molded and the surface area (S ₃ ) of the fixed mold plate corresponding to the outer peripheral surface of the bottomed container to be molded. (S ₁ / S ₃ ) = 0.86.

As a result, at the time of molding, the molded bottomed container was clogged in the fixed mold plate 12, and continuous production could not be performed.

[0038]

[Effects of the Invention] The injection molding die of the present invention has the above-described configuration, and thus, when the mold is opened, the bottomed container is securely attached to the movable mold without being left on the fixed side mold plate. Can be taken out in a state. As a bottomed container, there is a flange etc. at the mouth
Even without a bottomed container, without leaving it on the fixed side template,
Can be taken out while securely attached to the movable mold
You. In addition, the obtained bottomed container has an extreme gradient on the outer peripheral surface,
Because there is no convex part on the inner peripheral surface, it is excellent in appearance and can be easily packed in a box, etc. In addition, it is used for applications such as plugging without burrs along the circumferential direction outside the open end surface. When opening the plug, the finger does not tear.

[0039]

[Brief description of the drawings]

FIG. 1 is a partially cutaway sectional view showing an example of an injection mold according to the present invention.

FIG. 2 is a sectional view showing a main part of the injection mold according to the present invention;

FIG. 3 is a cross-sectional view showing a test-tube-shaped bottomed container formed by using the injection molding die of the present invention.

FIG. 4 is a cross-sectional view showing a square cylindrical bottomed container formed by using the injection mold of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding die 11 Movable mold 12 Fixed mold plate 15 Movable mold plate 16 Fixed mold plate attachment plate 18 Runner stripper plate 19 Runner / gate connecting plate 20 Cavity 111 Core 112 Receiving plate 113 Stripper plate for protrusion 113b Expansion Diameter 122 Gate 181 Runner 182 Sprue 191 Runner

Claims (1)

(57) [Scope of request for utility model registration] 1. A movable mold having a core and a projecting stripper.
A plate is provided, and the movable core and
An injection molding die having a cavity corresponding to the shape of a bottomed container to be molded between a top plate and a fixed side mold plate, and a movable stripper for projecting a movable mold when the mold is closed.
Bonding surface between the over plate and the fixed die plate, are arranged along the circumferential direction of the intermediate position of the outer peripheral surface of the bottomed container to be molded, and, corresponding to the inner peripheral surface of the bottomed container to be molded A stripper plate for projecting a movable mold corresponding to an outer peripheral surface of a bottomed container to be molded on a surface area (S1) of a movable mold core.
(S1 + S2) to which the surface area (S2) is added, and the surface area of the fixed mold plate corresponding to the outer peripheral surface of the bottomed container to be molded
(S3) the ratio of the [(S1 + S2) / S3] 1.05
A mold for injection molding characterized by the above.