JP3121238B2 - Injection compression molding mold and injection compression molding method - 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 compression molding die and an injection compression molding method often used for molding a thin molded product.

[0002]

2. Description of the Related Art In an injection compression molding method, a resin is injected into a cavity while a mold is opened by a predetermined amount, and after the filling is completed, the mold is closed and the resin is pressurized by the compression force. It is a method of molding. Therefore, as the mold used for injection compression molding, a mold having a receiving-portion-shaped divided surface and forming a closed portion including a cavity before completely closing the mold is used.

[0003] As described above, the injection compression molding method has the advantages that the resin is pressurized by the compression force of the mold, so that the injection pressure can be reduced, and that excessive residual stress at the gate portion is prevented.
This is a molding method often used in molding ultra-thin molded articles such as optical parts and IC cards.

[0004] For example, as an example of a method of forming an IC card base material, Japanese Patent Application Laid-Open No. 6-285928 discloses, as shown in FIG. The sliding block 115 having a shape corresponding to the size of
A molding method using a mold in which a cavity 120 and a gate 123 are formed between the mold 15 and 15 is disclosed.

[0005] In order to mold an IC card base material using the above-mentioned mold, first, the fixed mold 101 and the movable mold 104 are closed, and the sliding block 115 is retracted. Next, a required amount of molten resin for molding is injected into the cavity 120 from the injection molding machine (not shown) via the sprue 121.

During or after the injection of the molten resin and before the molten resin is solidified, the hydraulic cylinder 116 is driven to move the sliding block 115 forward as shown in FIG. As a result, the thickness of the cavity 120 is reduced, the cavity 120 is filled with the molten resin, and the molten resin is pressurized by the compressive force of the sliding block 115. After cooling and solidifying the molten resin, the mold is opened and the molded IC card base material is taken out. The molded IC card substrate is
Since the resin solidified by the gate 123 and the sprue 121 is integrated, the gate portion is cut after the molded IC card base material is taken out.

Although the above-described molding method does not apply a compressive force to the molten resin by moving the movable mold 104, it is a type of injection compression molding in that the thickness of the cavity 120 is reduced to apply a compressive force. .

[0008]

However, in the above-mentioned conventional injection compression molding method, since the molded product taken out of the mold has an integrated gate portion, the gate cut of the molded product taken out of the mold is performed. A processing step is required.
The molded product taken out of the mold was already solidified, and cutting of the solidified resin did not make the cut surface clean and was undesirable in appearance.

Accordingly, an object of the present invention is to provide an injection compression molding die and an injection compression molding method which do not require gate cutting after molding.

[0010]

In order to achieve the above object, an injection compression molding mold according to the present invention comprises a pair of slidable fittings, wherein the pair of dies is completely closed. A cavity is formed before, and the cavity is compressed by completely closing the pair of dies. In the injection compression molding mold, one of the pair of dies is provided.
Before the molds are completely closed, the other
A gate is formed in contact with the mold, and the pair of molds is closed.
With the same operation, the gate is pressed by the other mold and the gate is
Move the one mold to a position that is cut off from the cavity.
And a sliding member that slides .

[0011]

In this case, the sliding member is biased toward the other mold by a biasing means, or the sliding member is closed by the sliding member when the pair of molds is completely closed. The urging force of the urging means may be acting in the previous state.

[0013] injection compression molding method of the present invention, a pair of forming a cavity before it is completely closed sliding fit together
A mold, provided in one of the pair of molds,
Before the pair of molds is completely closed,
Contact to form a gate, for the mold closing operation of the pair of molds
With being pressed by the other mold,
Using an injection compression mold and a sliding member is slid Te, before the pair of molds are completely closed, before
Injecting the molten resin into the cavity through the gate, and after injecting the molten resin , furthermore,
Close and move the sliding member to lock the gate
With blocking against Viti, pressure of the cavity
Shrinking step.

[0014]

In the injection compression molding die according to the present invention, the molten resin is injected into the cavity before the die is completely closed, and the die is injected before the injected molten resin solidifies. Close completely and compress the cavity. The gate, which is the entrance of the molten resin into the cavity, closes the mold.
The gate is cut off before solidification of the molten resin because the gate is cut off with the operation. That is, since the gate is cut by compressing the cavity, a molded product having no gate trace can be obtained.

In this case, the gate is isolated from the cavity.
In one configuration, the mold is completely closed
The sliding member that contacts the other mold and forms a gate between the other mold before being pressed is pressed by the other mold with the closing operation of the mold to a position where the gate is cut off from the cavity.
Achieved by providing a slide with respect to one mold
ing. As a result, the gate and the associated resin passage are formed on the divided surface of the mold. As a result, the resin solidified in the gate and the resin passage is exposed by opening the mold, and the resin is easily taken out. Moreover, the other mold
The positional relationship with the sliding member does not change and the volume of the gate changes.
There is no backflow of the molten resin.

In this case, by urging the sliding member toward the other mold by the urging means, when the mold is completely closed, the sliding member is pressed by the other mold. Retreat by Therefore, no driving means or control means for moving the sliding member is required, and the configuration of the mold is simplified. In particular, by applying the urging force of the urging means already in a state where the mold is opened by the predetermined amount, the sealing property of the gate is improved, and leakage of the molten resin from the gate is prevented.

In the injection compression molding method of the present invention, first, the molten resin is injected into the cavity before the mold is completely closed, and then the mold is completely closed before the molten resin is solidified. At this time, the mold is completely closed
Before making contact with the counterpart mold to form the gate, the mold closing movement
One of the sliding members pressed by the mold on the other side
Since the mold for injection compression molding provided in the other mold is used, the gate is shut off at the same time as the mold is completely closed. If the molten resin is cooled and solidified as it is, the resin in the cavity is separated from the resin in the gate and solidified, so that the gate cutting process after molding becomes unnecessary, and the process is simplified.

[0018]

Next, the present invention will be described with reference to the drawings.

(First Embodiment) FIG. 1 is a sectional view of a first embodiment of an injection compression molding die according to the present invention. As shown in FIG. 1, the mold according to the present embodiment is preferably used for molding a thin molded product such as a base material for an IC card. Before cavity 2
The main components are a fixed mold 1 and a movable mold 4 in which 0 is formed, and a runner block 8 as a sliding member provided in the movable mold 4.

The fixed mold 1 is mounted on a fixed mounting plate 2 which is fixed to a fixed plate (not shown) of the injection molding machine. In the fixed mold 1, a plurality of recesses 1 a for forming a cavity 20 with the movable mold 4, and grooves serving as gates 23 and runners 22 communicating with the respective recesses 1 a are formed. The depth D of the concave portion 1a is larger than the thickness of the molded product.

A sprue bush 3 is attached to the center of the fixed-side mounting plate 2 and the fixed-side mold 1 so as to pass therethrough. One end of the sprue bush 3 is joined to a nozzle (not shown) of the injection molding machine, and the other end is formed with a sprue 21 communicating with the runner 22. An ejector mechanism 10 for projecting a molded product is provided for each recess 1a.

On the other hand, the movable mold 4 is attached to a movable plate-side mounting plate 5 fixed to a movable plate (not shown) of the injection molding machine via a spacer block 6 and a receiving plate 7.

In a region where the cavity 20 of the movable mold 4 is not formed, a stepped through hole 4a formed in the thickness direction of the movable mold 4 is opened. The outer shape of the runner block 8 matches the shape of the through hole 4a, and the runner block 8 is slidably provided in the through hole 4a in the thickness direction of the movable mold 4. The above-mentioned groove formed in the fixed mold 1 is closed by the contact surface of the runner block 8 with the fixed mold 1 when the runner block 8 contacts the fixed mold 1. Form a runner 22 and a gate 23. The contact surface between the runner block 8 and the fixed mold 1 constitutes a part of the divided surface of the mold.

In order to regulate the amount of movement of the runner block 8 in the direction of the fixed mold 1 on the end face of the runner block 8 on the receiving plate 7 side, a flange portion 8a which comes into contact with the step portion of the through hole 4a. Are formed. At a position where the flange portion 8a is in contact with the step portion of the through hole 4a of the movable mold 4, the runner block 8 protrudes from the distal end surface of the movable mold 4. A compression coil spring 9 as an urging means is provided between the runner block 8 and the receiving plate 7. The spring force of the compression coil spring 9 urges the runner block 8 toward the fixed mold 1. Have been. That is, when the mold is opened, the runner block 8 protrudes from the front end surface of the movable mold 4.

Thus, the fixed mold 1 and the movable mold 4
1 and the state shown in FIG. 1, before both are completely closed, the runner block 8 comes into contact with the fixed mold 1 as shown in FIG. It is formed. Further, by completely closing the fixed mold 1 and the movable mold 4, the movable mold 4 compresses the cavity 20 while sliding, but the gate 23 is connected to the fixed mold 1 and the movable mold 4. The mold 4 is formed at a position where the mold 4 is completely closed and the cavity 20 is blocked by being compressed.

The end of the runner block 8 on the side of the fixed mold 1 facing the sprue 21 is provided with a material pool 8b.
Are formed. Ejector pin 1 for projecting runner
1 is provided so as to be able to protrude from the material pool 8b.

In order to form a molded product using the mold having the above-described structure, first, the movable-side mounting plate 5 is advanced to fit the movable-side mold 4 and the fixed-side mold 1 to each other, and the runner block 8 is formed. Is brought into contact with the fixed mold 1 to form a cavity 20 between the movable mold 4 and the fixed mold 1. At this time, the fixed mold 1 and the movable mold 4 are not completely closed but only C is open. In particular, in this embodiment, when the fixed mold 1 and the movable mold 4 are opened only by C, the fixed mold 1 presses the runner block 8 toward the movable mold 4, and the compression coil spring 9 is slightly compressed. This allows
The spring force of the compression coil spring 9 acts on the runner block 8. At this time, it is desirable that the position of the distal end surface of the runner block 8 be a position that does not retreat with respect to the distal end surface of the movable mold 4. This is to prevent the cross-sectional area of the gate 23 from becoming small and hindering the injection of the molten resin into the cavity 20.

Next, the required amount of molten resin for molding is injected into the mold through the sprue bush 3 from the nozzle of the injection molding machine. The molten resin is sprue 21, runner 22
And is injected into the cavity 20 sequentially through the gate 23. At this time, since the runner block 8 is pressed against the fixed mold 1 by the compression coil spring 9, the runner block 8 is pressed.
2 and the gate 23 are improved in sealability, and leakage of the molten resin from the runner 22 and the gate 23 is prevented.

During or after the injection of the molten resin and before the molten resin is solidified, the movable mold 4 is moved forward as shown in FIG. 3 to completely move the movable mold 4 and the fixed mold 1 together. Close to. At this time, the runner block 8 also attempts to move forward, but cannot move forward any more because the runner block 8 is already in contact with the fixed mold 1, and the movement stroke of the runner block 8 is reduced by the compression coil spring 9. Absorbed.
As the movable mold 4 advances, the cavity 20 is compressed to a thickness of the molded product. Thereby, a compressive force is applied to the molten resin in the cavity 20, and the cavity 20 is filled with the molten resin.

The gate 23 is automatically shut off by the end face of the movable mold 4 simultaneously with the advance of the movable mold 4. That is, the gate cut processing is performed. Since the gate cut processing is performed by compressing the cavity 20, the trace of the gate 23 does not exist in the molded product. Furthermore, although the cavity 20 is compressed by completely closing the movable mold 4 and the fixed mold 1, the positional relationship between the fixed mold 1 and the runner block 8 does not change, and the gate 23,
Since the volumes of the runner 22 and the sprue 21 do not change, backflow of the molten resin does not occur.

After cooling and solidifying the molten resin, the movable mold 4 is retracted to open the mold, and the molded product in the cavity 20 is ejected from the fixed mold 1 by the ejector mechanism 10. Since the molded product is separated from the gate 23 before it is solidified, a gate cutting process after molding is not required, and the process is simplified. Further, as described above, since there is no gate mark on the molded product, the appearance of the molded product is not impaired, and
In the case of a molded product that needs to be decorated on the surface, the surface has good decorating properties, which is particularly effective for molding IC card base materials.

On the other hand, since the runner 22 and the gate 23 are formed between the runner block 8 and the fixed mold 1,
The resin in the sprue 21, the runner 22, and the gate 23 is exposed by opening the mold, and as the movable mold 4 moves,
It is pulled out of the fixed mold 1 integrally with the runner block 8. The drawn resin is ejected from the runner block 8 by the ejector pins 11. In addition, the force applied to the runner block 8 is released by the mold opening, and the distal end surface of the runner block 8 returns to a state in which the tip surface of the runner block 8 protrudes from the movable mold 4 by the spring force of the compression coil spring 9.

(Second Embodiment) FIG. 4 is a sectional view of a second embodiment of the injection compression molding die according to the present invention. The mold of the present embodiment is an example in which the movable mold 54 and the fixed mold 51 have the opposite relationship to that of the first embodiment.

As shown in FIG. 4, a plurality of recesses 5 whose depth D 'is larger than the thickness of the molded product for forming a cavity 70 between the movable mold 54 and the fixed mold 51 are formed.
On the other hand, the runner block 58 is provided on the fixed mold 51 so as to be slidable in the thickness direction of the fixed mold 51. The runner block 58 includes the fixed-side mounting plate 52.
The tip of the runner block 58 protrudes from the fixed mold 51 by being urged toward the movable mold 54 by a compression coil spring 59 provided between them. Runner block 5
8 is provided with a gate 73 communicating with the cavity 70.
And a groove serving as a runner 72 is formed.

Thus, when the fixed mold 51 and the movable mold 54 are fitted together, the runner block 58 abuts on the movable mold 54 before the two are completely closed, and the movable mold 54 is engaged. The runner 72 and the gate 73 are formed by the runner block 58 and the runner block 58, and the cavity 70 is formed by a portion surrounded by the fixed mold 51, the movable mold 54 and the runner block 58. Further, the fixed mold 51
By completely closing the movable mold 54 and the movable mold 54, the movable mold 54 slides to compress the cavity 70, but the gate 73 compresses the cavity 70 to fix the fixed mold 5.
It is formed at a position that is cut off at 1.

A sprue 71 is formed at the center of the runner block 58, and the runner block 58 also serves as a sprue bush.

In order to form a molded product using the mold having the above structure, first, the movable mold 54 is advanced and the movable mold 5 is moved.
4, the tip of the fixed mold 51 is fitted to the movable mold 5.
A cavity 70 is formed between the mold 4 and the fixed mold 51. At this time, the mold is not completely closed, but the runner block 58 is pressed by the movable mold 54 by the urging force of the compression coil spring 59, and the gate 73 and the runner block 72 are formed.

Next, a required amount of molten resin for molding is injected into the mold through a runner block 58 from a nozzle (not shown) of the injection molding machine. The molten resin is sprue 7
1. Injected into the cavity 70 through the runner 72 and the gate 73 sequentially. After the molten resin is injected and before the molten resin is solidified, the nozzle of the injection molding machine is runner block 5
Then, the movable mold 54 is advanced, and the movable mold 54 and the fixed mold 51 are completely closed.

By completely closing the mold, the thickness of the cavity 70 becomes the thickness of the molded product, a compressive force is applied to the molten resin in the cavity 70, and the cavity 70 is filled with the molten resin. At the same time, the runner block 58
The pressing force of the movable mold 54 causes the compression coil spring 59 to move.
It is pushed into the fixed mold 51 against the urging force.
Thereby, the gate 73 is automatically shut off by the end face of the fixed mold 51.

After cooling and solidifying the molten resin, the movable mold 54 is retracted to open the mold, and the molded product in the cavity 70 and the solidified resin in the other portions are removed from the movable mold 54 by the ejector mechanism. Stick out. Since the gate 73 is shut off before the resin is solidified, the molded product and the solidified resin in the other portions are separated from each other, and the gate cut processing after the molding is not required.

[0041]

As described above, in the injection compression molding die according to the present invention, the gate, which is the entrance of the molten resin into the cavity, is cut off during the compression step of the cavity. It is possible to obtain a molded article having excellent appearance and surface decoration.

In addition, by providing one of the molds with a sliding member which abuts on the other mold and forms a gate,
The resin solidified in the gate and its associated resin passage can be easily removed from the mold and melted.
The backflow of the resin can be prevented.

According to the injection compression molding method of the present invention, the mold is brought into contact with the other mold before the mold is completely closed.
To form a gate, and the mold closes
The gate is shut off at the same time as the cavity is compressed by using the injection compression molding die provided with the sliding member pressed in the one die, and the resin in the cavity and the resin in the gate are molded. Can be separated at the same time. Therefore, a gate cutting process after molding is not required, and the molding process can be simplified.

According to the injection compression molding method of the present invention, the gate is shut off simultaneously with the compression of the cavity by using the injection compression molding die formed at a position where the gate is shut off by the compression of the cavity. Thus, the resin in the cavity and the resin in the gate can be separated simultaneously with the molding. Therefore, a gate cutting process after molding is not required, and the molding process can be simplified.

[Brief description of the drawings]

FIG. 1 is a sectional view of a first embodiment of an injection compression molding die according to the present invention.

FIG. 2 is a sectional view taken along line AA ′ of the injection compression molding die shown in FIG.

FIG. 3 is a cross-sectional view showing a state in which the mold is completely closed in molding by the injection compression molding die shown in FIG.

FIG. 4 is a sectional view of a second embodiment of the injection compression molding die according to the present invention.

FIG. 5 is a sectional view of a main part of a conventional mold used for molding a thin molded product.

6 is a cross-sectional view of a main part showing a state in which a sliding block is advanced in molding by the mold shown in FIG. 5;

[Explanation of symbols]

 1, 51 Fixed mold 1a, 54a Recess 2, 52 Fixed mounting plate 3 Sprue bush 4, 54 Movable mold 4a Through hole 5 Movable mounting plate 6 Spacer block 7 Receiving plate 8, 58 Runner block 8a Flange 8b Material pool 9, 59 Compression coil spring 10 Ejector mechanism 11 Ejector pin 20, 70 Cavity 21, 71 Sprue 22, 72 Runner 23, 73 Gate

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor, Hitoshi Nakaji 4102-142, Miyanodai, Miyadera, Iruma-shi, Saitama Japan Steel Works Co., Ltd. (72) Inventor Haruki Ota 1-5-1, Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd. (72) Inventor Shigeru Uchida 2-664-8 Toyonodai, Otone-cho, Kita-Saitama-gun, Saitama Prefecture Inside Ikegami Die & Mold Co., Ltd. (56) References JP-A-4-22614 (JP, A (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/00-45/84 B29C 33/00-33/54

Claims (4)

(57) [Claims] 1. A pair of dies (1, 1) slidingly fitted to each other.
4, 51, 54), and the pair of molds (1, 4,
Cavities (20, 70) are formed before the complete closing of the pair of molds (1, 4,
In the injection compression molding die in which the cavities (20, 70) are compressed by completely closing the dies (51, 54), one of the dies (1, 4, 51, 54) is used.
The mold (4, 51) includes the pair of molds (1, 4, 51,
Before the other mold (1, 54) is completely closed,
To form gates (23, 73).
In addition to the above, with the closing operation of the mold (1, 4, 51, 54)
Is pressed by one of the molds (1, 54) and the gate (23,
73) is blocked from the cavities (20, 70).
Sliding to the one of the molds (4, 51).
A mold for injection compression molding, wherein a moving member (8, 58) is provided . 2. The injection device according to claim 1, wherein the sliding member (8, 58) is urged toward the other mold (1, 54) by urging means (9, 59). Mold for compression molding. 3. The urging means (9, 59) is attached to the sliding member (8, 58) before the pair of dies (1, 4, 51, 54) are completely closed. 3. The injection compression molding die according to claim 2, wherein the urging force is applied. 4. Before sliding fit completely closed to each other
A pair of molds (1, 1) forming a cavity (20, 70)
4, 51, 54) and the pair of molds (1, 4, 51, 5).
4) provided in one of the molds (4, 51);
Before the pair of molds (1, 4, 51, 54) are completely closed
Contact the other mold (1, 54) with the gate (23, 7).
3), the pair of molds (1, 4, 51, 54)
Pressed by the other mold (1, 54) with the mold closing operation of
And is slid with respect to the one mold (4, 51).
An injection compression molding die having sliding members (8, 58) is used, and the gates (23, 73) are provided before the pair of dies (1, 4, 51, 54) are completely closed. A step of injecting the molten resin into the cavity (20, 70) through the mold, and after the injection of the molten resin , the pair of molds (1, 4, 5,
(54), and further close the sliding members (8, 58).
Moving the gates (23, 73) into the cavity
With blocking against (20, 70), said cavity
Compression of the tee (20, 70) .