JP2565105Y2 - Resin gate structure of synthetic resin mold - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a resin gate structure of a synthetic resin molding die, the purpose of which is to simultaneously form bubbles, liquids, powders, etc. when the synthetic resin is molded by the die. Another object of the present invention is to provide a resin gate structure that allows foreign substances (such as resin) to be mixed into a synthetic resin.

(Conventional technology) Molding of a fusion molded resin in a mold cavity is widely performed by a molding method such as injection molding, compression molding and the like. It is used.

As one of the molding methods, for example, there is a method shown in FIGS. 6 (A) to 6 (D).

To explain this method, a mold (a) composed of an upper mold (b) and a lower mold (c) is arranged facing each other at a predetermined interval (see FIG. 6 (A)).

Next, the upper mold (b) is lowered, and the fused resin (e) is supplied from the resin gate (d) onto the lower mold (c) (see FIG. 6 (B)).

When the upper mold (b) and the lower mold (c) are engaged with each other, the fused resin (e) is shaped into the shape of the cavity (f) (the sixth mold).
FIG. (C)).

After the elapse of a predetermined time, when the upper mold (b) is raised, the synthetic resin molded body (g) is molded (see FIG. 6 (D)).

(Problems to be Solved by the Invention) In the above conventional molding method, there is no problem in obtaining a normal synthetic resin molded product. However, if a molded product having a foamed layer is to be obtained, the fusion molded resin itself is foamed. There has been no choice but to use a certain material (for example, foamed polyurethane or the like) or to mix water in an epoxy resin or the like and heat it to evaporate the water and at the same time mold-clamp.

Therefore, the types of synthetic resins that can be used are limited,
It has not been possible to diversify molded articles having a foamed layer.

In addition, JP-A-59-124822 and JP-A-2-178012 disclose molding apparatuses capable of mixing foreign substances into a synthetic resin by providing holes for supplying foreign substances in gate pins or gate pipes. I have.

However, in the molding apparatus disclosed in JP-A-59-124822, a hole for supplying foreign matter (axial passage in the rod) is opened to the side of the gate pin (rod member). Foreign matter whose specific gravity differs greatly from resin,
For example, when a gas or the like for forming a foam layer is supplied, the gas flows backward with the advance of the gate pin, and cannot be fed into the mold in a state of being uniformly mixed with the synthetic resin. Was.

Further, since the foreign material supply hole is opened toward the side of the gate pin, the supply of foreign material is limited until the gate pin closes the gate hole, and the timing is shifted from the synthetic resin to the inside of the mold. Could not inject foreign matter into

Moreover, since the tip of the rod member directly faces the inner surface of the mold, the temperature difference between the tip portion of the rod member facing the inner surface of the mold and the mold (the mold is higher and the rod member is lower) is used. In some cases, the resin in the portion facing the tip is cooled first, and this portion may be dented.

Therefore, when an opening for supplying a different material is provided at the tip of the rod member, a dent is formed in a portion facing the rod member, and a protrusion is formed in a portion facing the opening, and the surface of the molded product is formed. Irregularities may occur, and especially when attempting to manufacture a molded article having bubbles inside, bubbles may stagnate in the opening at the tip of the rod member, and that part may appear as a large dent on the surface of the molded product. there were.

Also in the molding apparatus disclosed in JP-A-2-178012,
Since a hole (colorant supply pipe) for supplying a foreign substance is provided behind the gate pipe (nozzle part), it is disclosed in Japanese Patent Application Laid-Open No. 59-124822.
The same problems as those of the molding apparatus disclosed in Japanese Patent Application Laid-Open No. H10-209,873 exist.

That is, since a hole for supplying foreign matter is provided behind the gate pipe, when foreign matter having a specific gravity greatly different from that of the synthetic resin for molding, for example, gas for forming a foamed layer is supplied, the gas is moved forward. That is, it could not be sent in the mold direction, and could not be mixed with the synthetic resin evenly and sent into the mold.

Furthermore, since the hole for supplying foreign matter is provided behind the gate pipe, the timing of foreign matter supply is limited, and the foreign matter cannot be injected into the mold by freely shifting the timing.

In view of the above circumstances, the present invention allows any type of synthetic resin molded article to have a foamed layer as desired, and furthermore, it is possible to mix a desired dye or the like into the synthetic resin by using a fusion molding resin during molding. Liquids (resins, etc.) and powders can be mixed, and even foreign substances having a specific gravity greatly different from that of synthetic resins, such as gases, can be fed into the mold in a completely mixed state. An object of the present invention is to provide a gate structure of a synthetic resin molding die in which the supply timing can be freely shifted and the surface of the molded product does not have irregularities.

(Means for Solving the Problems) The present invention is a resin gate structure provided in a mold of a synthetic resin molding die, and the gate structure is provided continuously from a molten synthetic resin supply unit, and the upper end is provided with the mold. A gate pipe facing the inner surface and a gate pin that is reciprocally movable in the longitudinal direction in the gate pipe and that opens and closes the gate hole, the upper end of the gate pipe having a thick portion inward. The lower surface is a tapered surface of the upper stop, and the outer surface of the upper end of the gate pin, which is the tapered surface of the upper stop, is allowed to be in close contact with the gate pin. Gate structure of a synthetic resin molding die in which an introduction path is formed or a resin gate structure in which a hole of an introduction path continuous from a supply unit is opened at a predetermined position on the inner surface of the gate pipe. Alternatively, the above problem is solved by a resin gate structure in which the hole is opened and closed as the gate pin is opened and closed by the gate pin.

(Operation) When the mold is clamped, the gate pin retreats in the gate pipe, so that the molten resin from the molten resin supply unit is supplied into the mold.

At the same time, a desired foreign substance is discharged from the supply section through an opening formed at the end of the gate pin or the inner surface of the gate pipe through an introduction path formed in the gate pin or the gate pipe, and the foreign substance is fed through the gate pipe. Mixed with resin.

The fused resin mixed with foreign matter is supplied into the mold through the gate hole in this state.

The fused resin is clamped in the mold, that is, in the cavity formed by the engagement of the mold, and is shaped to form a molded product in which desired foreign matter is mixed in the resin.

After the shaping is completed, the gate hole is closed by the gate pin. At the same time, the supply of foreign matter into the cavity is stopped by stopping the operation of the supply unit or closing the hole in the introduction path by the gate pin.

(Example) Hereinafter, an example of the resin gate structure of the synthetic resin molding die according to the present invention will be described with reference to the drawings.

1 to 3 show a mold embodying the present invention and a gate structure thereof.

In this embodiment, a mold for compression molding as described in the section of the prior art is used as a mold.

This mold has an upper mold (not shown) and a lower mold (1), and a gate portion (2) is provided at a predetermined position of the lower mold (1).

The gate structure of the gate portion (2) has a gate pipe (3) fitted into the mold from the inner surface of the lower mold (1) at substantially right angles, and reciprocates in the gate pipe (3) in the longitudinal direction, that is, in the vertical direction. Gate pin (4).

The upper end of the gate pipe (3) is an inward thick part, and the lower surface thereof is a tapered surface (3a) of an upper stop.

The outer surface of the upper end of the gate pin (4) is also a tapered surface (4a) of the upper stop, and this tapered surface (4a) can be in close contact with the tapered surface (3a) of the gate pipe (3).

That is, when the tapered surfaces (3a) and (4a) are in contact with each other, the gate hole (5) is closed.

As shown in FIG. 1, the gate pipe (3) is connected to a manifold pipe (6) having a molten resin supply passage (6a).

The gate pin (4) is provided below the gate pipe (3).
There is provided a gate pin drive mechanism (7) for reciprocally moving the gate up and down.

An introduction path (8) is formed in the gate pin (4) in the longitudinal direction of the gate pin (4), and a fine opening (8a) of the introduction path (8) is provided at the upper end of the gate pin (4). .

The introduction path (8) is provided continuously from a supply unit (not shown).

Gas, liquid such as colored ink, and foreign matter (resin and the like) such as powder are supplied to the supply section in advance, and the introduction path (8) is opened and closed by opening and closing a valve (not shown) controlled by an appropriate control mechanism.
The introduction of foreign matter into the sphere is regulated.

(9) is a heater for keeping the fusion resin fed through the gate pipe warm.

Next, the production of a synthetic resin molded body using a mold having this gate structure will be described.

As described with reference to FIGS. 6 (A) and 6 (B), when the upper mold is lowered to engage with the lower mold (1), the inside of the fusion resin supply section (6a) of the manifold tube and the gate pipe are connected. (3) The molten resin (10) circulated in the inside is supplied into the mold from the gate hole (5) opened by the lowering of the gate pin (4) driven by the gate pin driving mechanism (7).

At the same time, that is, when the gate pin (4) is lowered, the supply section is activated, and the inside of the introduction path (8) is air, a pigment, a liquid or the like, a desired foreign substance, or, in some cases, the same fused resin and a different color resin. The foreign matter (11) is injected upward from the opening (8a), and the fused resin (1) is discharged.
0).

All thermoplastic resins can be used as the fusion resin (10).

As shown in FIG. 3, the fused resin (10) is supplied to the inner surface of the lower mold (1) in a state where the foreign matter (11) has already been mixed at the time of exiting from the gate hole (5).

When a predetermined amount of the fusion resin (10) is supplied, the gate pin (4) is activated by the operation of the gate pin driving mechanism (7).
Is raised, and the tapered surface (4a) at the upper end thereof comes into close contact with the tapered surface (3a) at the upper end of the gate pipe (3), thereby closing the gate hole (5) (the state of FIG. 2).

In conjunction with this, the supply of the foreign matter by the supply unit is stopped.

The fused resin (10) containing the foreign matter (11) is formed in the upper and lower molds that have been clamped, and the mold is opened after a predetermined time has elapsed, and the synthetic resin molded product as a product is released from the mold. .

The synthetic resin molded article molded as described above has a foamed layer even though it is not made of a foamed synthetic resin, or is a quaint molded article in which pigments of a desired pigment are interspersed.

FIG. 4 shows a modified example of the gate structure. In this example, the introduction path (8) is formed in the thickness of the gate pipe (3) in a substantially horizontal direction, and the opening is formed on the inner surface of the gate pipe (3). And a hole (1) formed above the tapered surface (3a).
2)

In this gate structure, in the same process as described above, various foreign substances from the supply section are mixed into the fusion resin from the gate pipe, and when the supply of the fusion resin ends, the supply of the foreign substances is stopped in conjunction with this. .

FIG. 5 shows still another modification of the gate structure. In this example, as in the example of FIG. 4, the introduction path (8) is formed substantially in the horizontal direction in the thickness of the gate pipe (3). The opening is a hole (13) formed in the tapered surface (3a) of the gate pipe (3).

According to this gate structure, the tapered surface (4a) of the gate pin (4) is in close contact with the tapered surface (3a) of the gate pipe (3) to close the gate hole (5), and at the same time the tapered surface (4a) is closed. ) Closes the hole (13).

This stops the foreign matter from flowing out of the hole (13).

Therefore, according to this example, even if the supply unit is not provided with a valve mechanism that is automatically controlled, the gate pin (4) opens and closes the hole (13), so that foreign substances can flow into and out of the gate pipe (3). Done.

In addition, in the examples shown in FIGS. 4 and 5, the introduction path (8) is formed in the horizontal direction, so that even if the fused resin flows backward from the inside of the mold into the gate hole (5), the fused resin does not flow. It does not enter from (12) and (13) of the introduction path (8), and therefore, it is not preferable that foreign substances such as liquid and powder be mixed with the resin near the gate hole (5). Substance).

In the above-described embodiment, the compression mold is used as the mold. However, the mold is not limited to this, and another mold such as an injection mold may be used.

(Effects of the Invention) Since the invention has the above configuration, the following effects can be obtained.

That is, if a mold having a resin gate structure according to the present invention is used, for example, when molding a synthetic resin molded article having a foamed layer, the material is not limited to the foamed synthetic resin, and may be a thermoplastic resin. Whatever the synthetic resin, a foamed layer can be formed in a molded product, and it can meet the needs of diversified products.

In addition, according to the resin gate structure of the present invention, a liquid or powder for imparting a pattern, which has conventionally been difficult to mix into a synthetic resin molded article, can be mixed simultaneously with the molding of the synthetic resin, so that a synthetic resin product is desired. Easily.

In addition, even a foreign substance having a specific gravity greatly different from that of a synthetic resin such as a gas can be fed into the mold in a completely mixed state, and a synthetic resin molded article with a beautiful finish can be obtained.

Further, the timing of foreign matter supply can be freely changed, and a wide variety of synthetic resin molded products can be easily obtained.

Also, since the upper end of the gate pin abuts against the tapered surface and the gate pin tip does not directly face the cavity, even if an opening is provided at the gate pin tip, there is no unevenness on the surface of the molded product and a smooth surface. An excellent molded article having

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a synthetic resin molding die having a resin gate structure according to the present invention, FIG. 2 is a partial cross-sectional view of the resin gate structure near the upper part of the gate pipe, and FIG. FIG. 4 is a partial sectional view showing another embodiment of the resin gate structure according to the present invention, and FIG. FIGS. 6 (A) to 6 (D) are partial cross-sectional views showing still another embodiment of the gate structure, and FIGS. 6 (A) to 6 (D) are schematic cross-sections showing steps of molding a synthetic resin using a conventional mold (compression molding mold). FIG. (1) ... mold (lower mold), (2) ... gate part, (3) ... gate pipe, (4) ... gate pin, (5) ... gate hole,
(8) ... introduction path, (8a) ... opening, (12) (13) ... hole

Claims (3)

(57) [Scope of request for utility model registration] 1. A resin gate structure provided in a mold of a synthetic resin molding die, wherein the gate structure is provided continuously from a molten resin supply portion and has an end portion formed as a gate hole facing the inner surface of the mold. The gate pipe comprises a gate pipe and a gate pin which is reciprocally movable in the longitudinal direction in the gate pipe and opens and closes the gate hole.The gate pipe has a thick part inward at an upper end and a lower surface of the thick part. The upper end taper surface of the upper stop and the upper end outer surface of the gate pin which is the taper surface of the upper stop can be in close contact with each other. A resin gate structure of a synthetic resin molding die, characterized by being formed. 2. A resin gate structure provided in a mold of a synthetic resin molding die, wherein the gate structure is provided continuously from a molten resin supply portion and has an upper end formed as a gate hole facing the inner surface of the mold. A pipe and a gate pin that is reciprocally movable in the longitudinal direction in the gate pipe and opens and closes the gate hole. The gate pipe has an upper end portion having an inward thick portion and a lower surface of the thick portion having an upper surface. The outer surface of the upper end of the gate pin, which is a tapered surface of the throttle and which is a tapered surface of the upper throttle, can be brought into close contact with each other. A resin gate structure for a synthetic resin molding die, characterized in that a hole is opened. 3. A resin gate structure provided in a mold of a synthetic resin molding die, wherein the gate structure is provided continuously from a molten resin supply part and has an upper end formed as a gate hole facing the inner surface of the mold. A pipe and a gate pin which is reciprocally movable in the longitudinal direction in the gate pipe and opens and closes the gate hole, and a required portion of the inner surface of the gate pipe is provided with an opening of an introduction path continuous from a supply portion. The resin gate structure of the synthetic resin molding die is characterized in that this hole is opened and closed in accordance with opening and closing of the gate hole by the gate pin.