JPH07156189A - Molding die and method for injection moldings - Google Patents

Abstract

PURPOSE:To enhance the releasability of an unnecessary thread from a molding die by providing a resin charging area including an unnecessary part of a stretched thread to be embedded in a molded piece in addition to a resin charging area corresponding to the shape of the molded piece. CONSTITUTION:A twisted nylon fiber thread is stretched between resin charging areas 2 in the vicinities of both ends of arc-form base parts of molds 7, 8. The molds 7, 8 are closed. At this time, the both ends of the twisted nylon fiber thread outside the vicinities of the ends of the arc-form base parts are crushed by the molds 7, 8. When the molds 7, 8 are closed, the twisted nylon fiber thread outside the crushed part is cut off by a cutting edge 14. after that, a polystyrene resin is injected into the resin charging areas 2 from a gate 9. In this manner, the releasability of an unwanted thread 3 from the molding die can be enhanced in comparison with a prior art.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding die and method for molding a synthetic resin molded article in which a filament is embedded.

[0002]

2. Description of the Related Art Conventionally, a synthetic resin molded product 1 in which a filament 3 as shown in FIG. 5 is embedded (an interdental cleaning tool is shown) has been injection-molded as follows.

As shown in FIG. 6, first, the filament 3 is stretched between the molding dies 20, and then the dies 20 are closed. Simultaneously with the closing of the molding die 20, the unnecessary portion 30 of the filament 3 is cut. After that, the resin filling area 21 of the molding die 20
After filling and cooling with synthetic resin, the mold 20 is opened and the molded product 1 is taken out.

By the way, when the synthetic resin molded product 1 is taken out from between the molding dies 20, it is necessary to simultaneously remove the unnecessary filaments 30 cut during the molding from the molding dies 20. As a result, the unnecessary filamentous material 30 may remain attached to the inner surface of the molding die 20 and cannot be completely removed.

However, if the unnecessary filamentous material 30 remains in the molding die 20, when the molding die 20 is closed in the next molding cycle, the molds 20 cannot completely adhere to each other, and as a result, The mold 20 was sometimes damaged.

[0006]

SUMMARY OF THE INVENTION Therefore, the present invention provides a mold for molding a synthetic resin molded article and a molding method capable of enhancing the releasability of an unnecessary filamentous material from the inside of a molding die as compared with the prior art. It is what

[0007]

In order to solve the above problems, the present invention takes the following technical means.

A molding die for a synthetic resin molded article according to the present invention comprises a resin filling area 2 corresponding to the shape of the molded article 1,
It is characterized by having a resin filling region 4 including an unnecessary portion of the filamentous body 3 stretched for embedding in the molded product 1.

Further, the method for molding a synthetic resin molded product according to the present invention comprises a step of stretching the filamentous material 3 to be embedded in the molded product 1 over the molding dies 7 and 8, and the molding dies 7 and 8 described above. And the resin filling area 4 which should include the resin filling area 2 corresponding to the shape of the molded article 1 and the unnecessary portion of the thread 3 described above. And a step of injecting and filling a synthetic resin.

[0010]

The present invention has the following actions.

When the molding die of the injection-molded article according to the present invention is used, the unnecessary portion of the stretched filamentous body 3 is integrated with the resin injected into the resin-filled area 4 which should contain it. . Therefore, when removing the unnecessary portions of the filamentous body 3 from the molding dies 7 and 8, the resin integrated with the filamentous body 3 may be taken out in the same manner as the molded article 1, and the static electricity as in the case of the filamentous body 3 alone. Is weakened.

According to the method for molding an injection-molded article of the present invention, an unnecessary portion of the stretched filament 3 is cut,
Then, it is integrated with the resin injected into the resin-filled area 4 that should contain this. Therefore, when removing the unnecessary portions of the filamentous body 3 from the molding dies 7 and 8, it is sufficient to take out the resin integrated with the filamentous body 3 in the same manner as the molded article 1. The action is weakened.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 1 to 5, in this embodiment, a molding die for molding an interdental cleaning tool for removing plaque and the like adhering between the dentitions was manufactured. The molding die of this injection-molded product has a resin-filled area 2 corresponding to the shape of the molded product 1 (see FIG. 5) and an unnecessary portion of the filamentous material 3 stretched to be embedded in the molded product 1. It has an encapsulating resin filling zone 4.

As shown in FIG. 5, the interdental cleaning tool includes an arcuate base portion 5 and a grip portion 6 extending from the arcuate base portion 5.
Both ends of the filamentous body 3 for removing dental plaque and the like are embedded and fixed in the vicinity of both end regions of the arcuate base portion 5. When using, the gripping portion 6 is grasped to insert the filamentous body 3 into the gap between the dentition and move it so as to scrape off plaque, thereby removing postprandial plaque and the like adhering thereto. . This interdental cleaning tool is effective in removing plaque between the dentition, which is difficult only by brushing the teeth with a toothbrush.
In this embodiment, a polystyrene resin, which is a thermoplastic resin, is used as the synthetic resin to be injected, and a nylon fiber twisted yarn is used as the filament 3.

Then, using a cavity mold 7 and a core mold 8 as shown in FIGS. 1 and 2, a polystyrene resin is filled in the resin filling area 2 corresponding to the shape of the interdental cleaning tool as the molded product 1. Fill from gate 9. In the illustrated example, the molds 7 and 8 are formed so that two products can be taken in one cycle, and the twisted yarn of nylon fiber, which is the filament 3, is placed between the resin-filled regions 2 near both end regions of the arcuate base 5. I try to stretch. Further, 10 is a concave portion formed in the molds 7 and 8 to secure an area where the twisted yarn of nylon fiber should exist, and 11 is a concave groove having a V-shaped cross section similarly.

Further, the resin-filled area 4 is formed also in a portion where the twisted yarn of the nylon fiber as the filament 3 is stretched and which is an unnecessary portion on the outer side of each arcuate base 5.
Polystyrene resin is injected through gate 12. The twisted yarn of nylon fiber, which is the filament 3 at this point, is not necessary. However, it is integrated with the polystyrene resin injected into the resin filling region 4 including this unnecessary yarn portion, and is known from the molds 7 and 8 after the completion of molding. Mold 7 and 8 by sticking out by
Prevents thread remaining inside.

When the molding die for the injection-molded article of this embodiment is used, the unnecessary portion of the stretched filamentous body 3 is integrated with the resin injected into the resin-filled area 4 which should contain it. It Therefore, when the unnecessary portion of the filament 3 is removed from the molding die, the resin integrated with the filament 3 may be taken out in the same manner as the molded article 1. Weakened. Therefore, there is an advantage that the releasability of the unnecessary filamentous body 3 from the inside of the molding die can be enhanced more than ever before.

Next, a method of molding the injection-molded article of this embodiment will be described. This molding method includes a step of stretching a filamentous body 3 to be embedded in a molded article 1 on a molding die, and closing the molding die to cut an unnecessary portion of the filamentous body 3 stretched there. And a step of filling the resin-filled area 2 corresponding to the shape of the molded product 1 and the resin-filled area 4 which should include the unnecessary portion of the filament 3 with a synthetic resin.

That is, first, a twisted yarn of nylon fiber is stretched between the resin-filled regions 2 in the vicinity of both end regions of the arcuate base portions of the molds 7 and 8. Next, as shown in FIG. 4, the molds 7 and 8 are closed. At this time, the both ends of the twisted yarn of the nylon fiber and the outer side in the vicinity of both end regions of the arcuate base are crushed by the molds 7 and 8 (projections 13). Also,
When the molds 7 and 8 are closed, the cutting blade 14 cuts the outside of the crushed portion of the twisted yarn of the nylon fiber by the molds 7 and 8 (projection 13). After that, polystyrene resin is injected from the gate 9 into the resin filling area 2. Then, when the molding is completed, the product is obtained by protruding from the molds 7 and 8 by a known method.

By the way, the polystyrene resin is also applied to the resin-filled area 4 where the twisted yarn of the nylon fiber, which is the filament 3, is stretched and which should include the unnecessary portion on the outer side of each arcuate base 5. Is ejected from. It is possible to prevent the thread residue in the molds 7 and 8 by being integrated with the injected polystyrene resin in the resin filling area 4 including the unnecessary thread portion and protruding from the molds 7 and 8 by a known method after the molding is completed. .

According to the method for molding an injection-molded article of this embodiment, an unnecessary portion of the stretched filament 3 is cut,
Then, it is integrated with the resin injected into the resin-filled area 4 that should contain this. Therefore, when removing the unnecessary portion of the filamentous body 3 from the molding die, the resin integrated with the filamentous body 3 may be taken out in the same manner as the molded article 1, and the action of static electricity as in the case of the filamentous body 3 alone is weakened. To be Therefore, there is an advantage that the releasability of the unnecessary filamentous body 3 from the inside of the molding die can be enhanced more than ever before.

[0023]

The present invention has the above-mentioned structure and has the following effects.

When the unnecessary portion of the filament 3 is removed, the resin integrated with it may be taken out in the same manner as the molded product 1,
Since the action of static electricity as in the case of the filamentous body 3 alone is weakened, it is possible to enhance the mold releasability of the unnecessary filamentous body 3 from the molding die as compared with the conventional case, and a molding die and a molding method for an injection molded product. Can be provided.

[Brief description of drawings]

FIG. 1 is a front view of a cavity mold for explaining an example of a mold for molding an injection-molded article of the present invention.

FIG. 2 is a front view of a core mold for explaining an embodiment of a mold for molding an injection-molded article of the present invention.

FIG. 3 is a vertical cross-sectional view illustrating a state before the X portions of the molds of FIGS. 1 and 2 are closed.

FIG. 4 is a vertical cross-sectional view illustrating a closed state of the X portions of the molds of FIGS. 1 and 2.

5 is an overall perspective view illustrating an interdental-row cleaning tool molded by the molding die of FIGS. 1 to 4. FIG.

FIG. 6 is a schematic front view illustrating a conventional mold for molding an injection molded product.

[Explanation of symbols]

 1 Molded Product 2 Resin Filling Area 3 Filament 4 Resin Filling Area 7 Molding Die 8 Molding Die

Claims (2)

[Claims] 1. A resin containing a resin-filled area (2) corresponding to the shape of the molded product (1) and an unnecessary portion of the filamentous material (3) stretched to be embedded in the molded product (1). A mold for molding an injection-molded article, which has a filling area (4). 2. A step of stretching a filament (3) to be embedded in a molded product (1) on a molding die (7) (8), and closing the molding die (7) (8). Then, the step of cutting the unnecessary portion of the filamentous material (3) stretched over here, the resin filling area (2) corresponding to the shape of the molded product (1) and the unnecessary portion of the filamentous material (3) are included. Resin filling area to be used (4)
And a step of injecting and filling a synthetic resin into both of them.