JP3051901B2 - Injection mold for composite molding - 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 molding die for composite molding in which two different kinds of synthetic resins are alternately injected and molded integrally.

[0002]

2. Description of the Related Art For example, composite molded articles obtained by integrally molding a hard synthetic resin and a soft synthetic resin are widely used in the fields of vehicle parts, building materials, electric products and the like.

FIGS. 9A and 9B show a seat side shield 1 for covering a reclining device 2 of a vehicle seat as an example of a composite molded product, which prevents the reclining device 2 from being exposed and improves its appearance. It is necessary to eliminate or reduce the gap with the seat back 3 in order to prevent the entry of small objects. Therefore, the portion to be attached to the vehicle body is made of the hard material 4 and the contact portion with the seat back 3 is made of the soft material (elastomer). ) 5 and molded and integrated.

FIGS. 10 and 11 show a conventional injection molding die and a molding method for the above-mentioned seat side shield 1. In FIG.
A mold 7a (FIG. 10) that molds only the soft material 5 and a mold 7b (FIG. 11) that molds only the soft material 5 are prepared, and these are alternately exchanged to be injection molded and integrated. It is.

There is also a method in which the hard material 4 and the soft material 5 are separately formed by preparing separate molds, and integrated with each other by bonding or welding.

[0006]

However, in the former molding apparatus, two movable dies 7 are required, and the movable dies 7 are mounted in order to quickly exchange the two movable dies 7a and 7b. Since a molding machine having a rotary board is required, an increase in equipment cost is inevitable. In addition, since it takes time to change the mold and the mold temperature decreases, there is a difficulty in controlling the molding temperature. In order to recover the conditions, a molding cycle is lengthened, and a temperature holding facility during standby is required.

In the latter method of integration by welding or the like,
Again, individual molding dies are required, and the number of steps for welding and bonding the hard material 4 and the soft material 5 increases, so that the total cost increases.

In the case of welding or bonding, the required strength is often not obtained by welding or bonding the end faces.
Overlap both ends to the main material side (eg polypropylene)
The boss formed in the above is aligned with the boss hole on the sub-material side (elastomer), and the boss is melted and welded. However, peeling due to poor welding easily occurs, which is a factor of defective products.
Further, in this case, since the end face is not welded, there is a problem that the end face is exposed, dust or the like invades, and the external appearance is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been developed to provide a composite molded product having high strength and good appearance, which can be molded efficiently and at low cost with one molding die. It aims to provide injection molding dies.

[0010]

In order to achieve the above object, a first aspect of the present invention is an injection molding die having a fixed side 10 and a movable side 20. A first sprue 12 for the first resin communicating with one end of the first cavity 11 through the gate 13, and a second sprue for the second resin opening from the other end of the first cavity 11 to the boundary surface 21 with the movable side 20. Of the movable side 20 and the fixed side 1
0, a slide piece 22 is provided at the boundary between the slide piece 22 and the slide piece 22. The slide piece 22 can move forward and backward in the direction orthogonal to the mold opening direction.
And a second cavity 24 and a second gate 23 which respectively communicate with the other end of the first cavity 11 and the second sprue 14 at the time of retreat are provided in such a manner that they communicate with each other inside.

A second aspect of the present invention is an injection molding die including a fixed side 10 and a movable side 30, and the fixed side 10 communicates with one end of a first cavity 11 via a first gate 13. First sprue 12 for first resin and first cavity 1
A second sprue 14 for the second resin is provided at a boundary surface 21 with the movable side 30 that is separated from the other end of the movable side 30. A boundary between the movable side 30 and the fixed side 10 is orthogonal to the mold opening direction. The first slide piece 32 which can move forward and backward and seals the other end of the first cavity 11 and the second sprue 14 when moving forward.
And the first slide piece 32 can move forward and backward in the direction perpendicular to the direction of movement, and when the first slide piece 32 retreats, moves forward, and the other end of the first cavity 11 and the second sprue 1 move.
4, a second slide piece 36 provided with a second cavity 34 and a second gate 33 communicating with each other in the interior.

A third aspect of the present invention relates to an injection molding die having a fixed side 10 and a movable side 40, which communicates with one end of a first cavity 11 via a first gate 13. First sprue 12 for first resin and first cavity 1
A second sprue 14 for the second resin is provided at a boundary surface 21 between the movable side 40 and the movable side 40. The second sprue 14 for the second resin is provided at a boundary between the movable side 40 and the fixed side 10 at right angles to the mold opening direction. A first slide piece 42 that can move forward and backward, and seals the other end of the first cavity 11 and the second sprue 14 when moving forward.
The first slide piece 4 is movable up and down in the mold opening direction.
2, a second slide piece provided with a second cavity 44 and a second gate 43, which are raised when retracted and communicate with the other end of the first cavity 11 and the second sprue 14, respectively, so as to communicate with each other inside. 46, and the lower part of the second slide piece 46 is slidably engaged with the second slide piece 46 with unevenness formed on the mutually inclined surfaces, and in the direction orthogonal to the mold opening direction. A third slide piece 47 for moving the second slide piece 46 up and down by moving forward and backward is provided.

[0013]

1 to 3 show a first embodiment of the present invention. An injection molding die includes a fixed side 10 and a movable side 20. As the first resin a, for example, a polypropylene (P
A first sprue 12 for injecting P) and a second sprue 14 for injecting, for example, a thermoplastic elastomer serving as an auxiliary material (soft material) as the second resin b are provided as appropriate.

The first sprue 12 is located at the center of the mold,
The second sprue 14 communicates with one end of the first cavity 11 through the first gate 13, and penetrates the boundary surface 21 with the movable side 20 while being separated from the other end of the first cavity 11.

At the boundary between the movable side 20 and the fixed side 10,
For example, in the positional relationship from the back surface of the seat back 3 and the seat side shield 1 shown in FIG. 9B, a position corresponding to a soft material (elastomer) 5 formed in a state where there is no gap on the side of the seat back 3. Slide piece 2 placed
2 is installed so as to be able to advance and retreat in a direction orthogonal to the mold opening direction by the operation of the cylinder 25.

A second cavity 24 communicating with the other end of the first cavity 11 at a retracted position and a second gate 23 communicating with the second sprue 14 are provided on the upper surface of the slide piece 22. The opening is formed so as to communicate.

In this injection molding die, first, the slide piece 22 is advanced, and the other end of the first cavity 11 and the second sprue 14 are sealed. Inject the PP which is the first resin a into one cavity 11 (FIG. 1), and then slide the slide piece 2
2 with the second cavity 24 and the second gate 23 communicating with the first cavity 11 and the second sprue 14, respectively, in the second cavity 24 via the second sprue 14 and the second gate 23, The elastomer as the second resin b is injected and fused with the first resin a (FIG. 2) to form a composite molded article c. Thereafter, the mold is opened, and the composite molded article c is released from the mold by a protrusion or removal mechanism (not shown) (FIG. 3).

FIGS. 4 and 5 show an embodiment of the second invention. The fixed side 10 of the injection mold has the same structure as that of the first invention. Is omitted.

At the boundary between the movable side 30 and the fixed side 10,
The first slide piece 32 arranged at the same position as the slide piece 22 of the first invention is installed so as to be able to advance and retreat in a direction orthogonal to the mold opening direction by the operation of the cylinder 35 (FIG. 4). A second slide piece 36, which can be moved back and forth in a direction perpendicular to the direction in which the first slide piece 32 is moved, is installed in an air space formed by the retreat of the first slide piece 32, which is connected to a cylinder 37 (FIG. 5).

On the upper surface of the second slide piece 36, at its forward position, a second cavity 34 communicating with the other end of the first cavity 11 and a second gate 33 communicating with the second sprue 14. , Are formed so as to communicate with each other.

In this injection molding die, first, the first slide piece 32 is advanced, and the other end of the first cavity 11 and the second sprue 14 are sealed. Then, PP, which is the first resin a, is injected into the first cavity 11 (FIG. 4), and then the first slide piece 32 is retracted and the second slide piece 36 is advanced to advance the first cavity 11 and the second sprue 14. With the second cavity 34 and the second gate 33 being in communication with each other, the second resin b is injected into the second cavity 34 through the second sprue 14 and the second gate 33 to release the first resin b. It is fused with the resin a (FIG. 5) to form a composite molded article c. After that, open the mold in the same way as in FIG.
The composite molded product c is released from the mold by a protrusion mechanism not shown.

FIGS. 6 to 8 show an embodiment of the third invention. The fixed side 10 of the injection mold has the same structure as that of the first invention. Is omitted.

At the boundary between the movable side 40 and the fixed side 10,
A first slide piece 42 arranged at the same position as the slide piece 22 of the first invention is installed so as to be able to advance and retreat in a direction orthogonal to the mold opening direction by operation of a cylinder 45, and the first slide piece 42 is provided. 42, the second slide piece 4 capable of moving back and forth (elevating and lowering) in the mold opening direction in the airspace due to the retreat.
6 are arranged.

On the upper surface of the second slide piece 46, at its raised position, a second cavity 44 communicating with the other end of the first cavity 11 and a second gate 43 communicating with the second sprue 14. , Are formed so as to communicate with each other. The lower surface is the first slide piece 4
2 and is inclined in a direction orthogonal to the direction of retreat, and a groove-shaped engaging concave portion 49 is formed along the inclined direction.

Below the second slide piece 46, a third slide piece 47 which can move forward and backward in a direction perpendicular to the direction of movement of the first slide piece 42 is connected to a cylinder 48 and installed. The upper surface of the distal end portion of the third slide piece 47 is inclined corresponding to the lower surface of the second slide piece 46, and an engagement projection 50 slidably engaged with the engagement recess 49 is formed. I have.

In this injection molding die, first, the first slide piece 42 is advanced, and the other end of the first cavity 11 and the second sprue 14 are sealed. By injecting PP as the first resin a into the first cavity 11 (FIG. 6), the first slide piece 42 is then moved backward, and the third slide piece 47 is moved forward, so that the second slide piece 46 is advanced. In a state where the second cavity 44 and the second gate 43 are communicated with the first cavity 11 and the second sprue 14, respectively, and the second cavity 44 and the second sprue 14 are inserted into the second cavity 44 via the second sprue 14 and the second gate 43. The two resin b elastomer is injected and fused with the first resin a (FIGS. 7 and 8) to form a composite molded article c. Thereafter, the mold is opened in the same manner as in FIG. 3, and the composite molded article c is released from the mold by a projection mechanism not shown.

Although the above embodiment has described the formation of the seat side shield, the present invention is not limited to this, and it is not limited to this. It can be applied to molding of easy-to-make parts and contact parts with the human body.

Although the second resin is a thermoplastic elastomer, the present invention is not limited to this. For example, it is also possible to use the same hard resin having a different color as the first resin.

[0029]

According to the present invention, the molding of two different types of resin is performed by operating the slide piece without exchanging the molds, so that the conventional mold requiring two molds can be made into one mold. This makes it possible to significantly reduce equipment costs.

In addition, since the time for changing the mold is not required, and the molding conditions at the mold temperature are easily maintained, the molding cycle can be shortened and the molding can be performed efficiently, and the total cost can be reduced.

Furthermore, since the second resin is rapidly injected and integrally molded with the first resin that is still in a state of softening and melting immediately after injection, the end faces of each resin are firmly fused to each other, and the strength is stabilized. At the same time, the appearance is good, and the conventional steps such as welding can be omitted.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first resin molding according to an embodiment of the first invention.

FIG. 2 is a cross-sectional view at the time of molding a second resin.

FIG. 3 is a cross-sectional view when the mold is opened and released.

FIG. 4 is a cross-sectional view showing the embodiment of the second invention at the time of molding the first resin.

FIG. 5 is a sectional view taken along the line VV of FIG. 4 showing the second resin molding.

FIG. 6 is a cross-sectional view of the third embodiment at the time of molding the first resin.

FIG. 7 is a cross-sectional view when the second resin is molded.

FIG. 8 is a sectional view taken along the line VIII-VIII of FIG. 7;

FIG. 9 shows a schematic configuration of a seat side shield.
(A) is a side view, (B) is a view in the direction of arrow B in (A).

FIG. 10 is a cross-sectional view of a conventional composite molding injection mold during first resin molding.

FIG. 11 is a cross-sectional view at the time of molding the second resin.

[Explanation of symbols]

 Reference Signs List 10 Fixed side 11 First cavity 12 First sprue 13 First gate 14 Second sprue 20, 30, 40 Movable side 21 Boundary surface 22 Slide piece 23, 33, 43 Second gate 24, 34, 44 Second cavity 25, 35, 37, 45, 48 Cylinder 32, 42 First slide piece 36, 46 Second slide piece 47 Third slide piece a First resin b Second resin c Composite molded product

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-62-273815 (JP, A) JP-A-8-276463 (JP, A) JP-A-9-76289 (JP, A) JP-A-5-276289 31765 (JP, A) JP-A-7-68600 (JP, A) JP-A-54-131571 (JP, U) JP-A-3-79919 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 45/26-45/44

Claims (3)

(57) [Claims] An injection mold comprising a fixed side and a movable side, wherein a fixed side has a first sprue for a first resin which communicates with one end of a first cavity through a first gate. A second sprue for a second resin, which is separated from the other end of the first cavity and opens at a boundary surface with the movable side, at a boundary between the movable side and the fixed side, in a direction orthogonal to the mold opening direction. A slide piece capable of moving forward and backward is provided, the slide piece seals the other end of the first cavity and the second sprue when moving forward, and communicates with the other end of the first cavity and the second sprue when moving backward. And a second molding, wherein the second gate is provided so as to communicate with each other inside. 2. A mold for injection molding comprising a fixed side and a movable side, wherein the fixed side has a first sprue for a first resin which communicates with one end of a first cavity through a first gate. A second sprue for a second resin, which is separated from the other end of the first cavity and opens at a boundary surface with the movable side, at a boundary between the movable side and the fixed side, in a direction orthogonal to the mold opening direction. It is possible to advance and retreat, and a first slide piece that seals the other end of the first cavity and the second sprue at the time of advancement, and is able to advance and retreat in a direction orthogonal to the advance and retreat direction of the first slide piece,
A second slide piece, which is advanced when the first slide piece retreats and is provided with a second cavity and a second gate communicating with the other end of the first cavity and the second sprue, respectively, in a form communicating with each other inside, A composite molding injection mold with a 3. An injection mold comprising a fixed side and a movable side, wherein the fixed side includes a first sprue for a first resin which communicates with one end of a first cavity through a first gate. A second sprue for a second resin, which is separated from the other end of the first cavity and opens at a boundary surface with the movable side, at a boundary between the movable side and the fixed side, in a direction orthogonal to the mold opening direction. A first slide piece that can move forward and backward, and seals the other end of the first cavity and the second sprue when moving forward, and can move up and down in the mold opening direction, rises when the first slide piece retreats, A second cavity and a second gate respectively communicating with the other end of the cavity and the second sprue,
And a second slide piece provided in a form communicating with each other inside, and slidably engages with the second slide piece below the second slide pieces by means of unevenness formed on mutually inclined surfaces. And
An injection molding die for composite molding, in which a third slide piece that moves up and down the second slide piece by moving back and forth in a direction orthogonal to the mold opening direction is installed.