JPH0439013A - Mold for composite molded body - Google Patents

Abstract

PURPOSE:To obtain a molded object having a uniform quality extensively, by a method wherein a movable weir member is provided in a mold, molten resin to be injected into a space between a stationary and movable molds is stemmed once, stuck to the surface of the stationary mold and at the time of mold clamping the resin is brought into contact with the whole surface of a skin material by one effort. CONSTITUTION:A fixed skin material 8 is stuck to a fixed part of a movable mold 3 under a state where the movable mold 3 is separated sufficiently from a stationary mold 2. Then a fixed quantity of molten resin 9 is injected under a state where a movable weir member 5 is projected in front of an opening of a gate. Then molten resin 9 is blocked by hitting against the tip part of the movable weir 5, reduced remarkably in speed and pressure, caused to adhere to a resin molding surface of the stationary mold, goes to the lower part along a mold surface, becomes lumpy and is kept flowing down slowly. In this instance, if an uneven number 7 having a large number of protrusions is provided on a sticking surface of the resin of the stationary mold 2, a flow speed of the molten resin is lowered reliably further. After completion of injection of the molten resin 9, a driving weir member 5 blocking the molten resin 9 is moved backward down to a shunting position. Then mold clamping is performed by moving a movable mold forward, cooled for a fixed time, then mold breaking is performed and a product is taken out.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to the production of a composite molded article made by pasting a desired skin material on the surface of a plastic base material for surface decoration or imparting desired functionality. Regarding the mold used.

[Conventional technology]

These composite molded products include, for example, interior materials for automobiles, but these composite molded products are usually made into highly decorative materials such as PVC leather and carpets by using adhesives on the base plastic molded product. It is made by pasting a skin material with a However, these often require time and effort to process when pasting the skin material, which limits designs, has a high defect rate, and increases manufacturing costs.

Therefore, a composite molded product covered with a skin material is obtained by using a special stamping molding machine, applying a skin material inside the mold in advance, then injecting molten resin into the mold and closing the mold. A method has also been proposed.

However, in conventional stamping molding methods of this type, when injection of molten resin is started, part of the resin immediately comes into contact with the skin material, while the skin material is completely covered with resin. Since it is covered only after the mold clamping is completed, the contact time between the resin and the skin material is partially different, so there are parts where the two come into contact at a high temperature and other parts where the temperature is slightly lower. Therefore, when trying to obtain a particularly large molded product, there is a drawback that it is difficult to obtain a homogeneous product.To solve this problem, the molten resin is placed evenly on the skin material, but the time required becomes longer. occurs.

More specifically, near the gate, the injected high-temperature resin collides directly with the surface of the skin material under high pressure and comes into contact with it, but at the edge piece far from the gate, the resin is Since the composite material comes into contact with the skin material at low temperature and low pressure, the thickness and density of the composite material may become uneven, and wrinkles and uneven gloss may occur on the surface, making it difficult to obtain a high-quality composite material. It is.

In order to solve the above-mentioned problems, a stamping molding machine has been proposed that injects and applies molten resin approximately evenly onto the surface of the skin material and then molds it, but this machine is expensive and The problems of long molding cycles, limited usable resins, and uneven resin temperature during molding have not been completely solved.

Further, the dedicated stamping device is not only expensive, but also requires a considerable amount of time to obtain a molded product of good quality.

[The invention or the problem the invention is trying to solve]

The present invention has been made in order to solve the above problems, and its purpose is to make the above-mentioned large-sized stamping molding machine by using an inexpensive general-purpose injection molding machine without requiring a special stamping molding device. The purpose is to provide a mold suitable for obtaining a composite molded product. More specifically, when obtaining a large composite molded product such as the one described above, the molten resin is heated under the same conditions as much as possible within the shortest possible time. The object of the present invention is to provide a novel mold that can obtain a molded product with uniform quality over the entire surface by bringing the molded product into contact with the skin material all at once.

[Failure to solve the problem]

The purpose of the above is to provide a movable dam member in the mold to temporarily dam the molten resin injected into the space between the fixed and movable molds, make it adhere to the surface of the fixed mold, and contact the skin material at an early stage. This is achieved by configuring the resin to come into contact with the entire surface of the skin material at once when the mold is clamped.

More specifically, the above purpose is to prevent the resin injected from the gate from protruding into the space between the fixed mold and the movable mold in a mold for obtaining the composite molded article as described above. reciprocating between a dam position where the passage is blocked at a close distance from the opening of the gate and a retracted position where it exits the molding space and forms part of its surface or substantially part of the mold surface; This is achieved by providing a movable dam member that can be moved in and out of the fixed mold, and by providing a drive device that reciprocates the movable dam member between the dam position and the retracted position.

The movable weir member is configured to perform linear movement, rotational movement, and combined movement thereof relative to the fixed mold,
At one end of the movement, the jet of resin injected from the gate is dammed, causing it to stick and stay on the resin molding surface of the fixed mold, and at the other end of the movement, the jet of resin injected from the gate is blocked, and at the other end of the movement, the mold closes and the resin molding becomes obstructed. They were forced to evacuate to a position where they would not be able to do so.

Therefore, the movement path between the dam position and the retracted position is as follows:
It can be a straight movement path, a parallel movement path, a swing path, and any combination thereof.

Another object of the present invention is to form appropriate irregularities, grooves,
This can be achieved even more reliably by providing a protrusion that can be moved in and out, or by making the surface a movable surface that can be swung.

[Effect]

With the above configuration, the molten resin can be uniformly brought into contact with the skin material at low pressure, evenly and within the shortest time, even if a general-purpose injection molding device is used without using a special stamping molding device, making it inexpensive. Moreover, it becomes possible to easily produce a high-quality composite molded body.

Furthermore, according to the present invention, it is possible to obtain a uniform composite even if a skin material that is relatively easily affected by heat is used, and it is also possible to create a composite with a special texture due to the influence of heat. becomes.

[Preferred embodiments for carrying out the invention] Preferred embodiments for carrying out the invention will be specifically described below with reference to the drawings.

1 to 4 are sectional views showing the state of each part of the mold at each step when obtaining a molded product using the mold according to the present invention, and FIG. 1 is a sectional view of the movable mold. Figure 2 is a cross-sectional view showing the state in which the movable dam member has been pulled away from the fixed mold and a skin material has been pasted on its surface. A sectional view showing the state in which the movable weir member is attached to and held on the resin molding surface, Fig. 3 is a sectional view showing the state in which the movable weir member is retracted to the retracted position, and Fig. 4 is a sectional view showing the state when the mold is closed and cooled. It is.

In the figure, 1 is an injection molding machine cylinder 2 is a fixed mold, 3 is a movable mold, 4 is a hydraulic cylinder 5 is a movable weir member,
6 is a link, 7 is an uneven member provided on the surface of the fixed mold 20,
8 is a skin material, and 9 is a molten resin.

The movable weir member 5 is held movably in a guide hole provided in the fixed mold 2 at a position close to the gate, and is connected to the rod of the hydraulic cylinder 4 via a link 6, as shown in FIG. and as shown in FIG. 2, the tip thereof protrudes into the resin molding space 2a toward the movable mold and crosses the path of the molten resin injected from the gate, and the dam position as shown in FIG. As shown in FIG. 4, the entire mold is retracted from the resin molding space, and its tip surface is capable of reciprocating between the retracted position and the retracted position where it substantially forms part of the fixed mold surface. It is configured.

When the movable weir member 5 is in the weir position, the molten resin injected from the gate is blocked by the movable weir member 5 and is adhered and held to the resin molding surface of the fixed mold 2, so that the resin is not directly injected. Never touch the skin material.

The operation of opening and closing the mold is the same as in the normal injection molding process, and the first
As shown in the figure, with the movable mold 3 sufficiently separated from the fixed mold 2, a predetermined skin material 8 is attached to a predetermined part of the movable mold 3, and then the movable weir member 5 is attached to the gate opening. A predetermined amount of molten resin 9 is injected in a state where it protrudes to the front.

The injected molten resin 9 hits the tip of the movable weir member 5 and is blocked, its velocity and pressure drop significantly, and it adheres to the resin molding surface of the fixed mold, forming a lump downward along the mold surface. It then slowly begins to flow down.

At this time, if a concavo-convex member 7 having a large number of protrusions is provided on the resin-attaching surface of the fixed mold 2, the flow rate of the molten resin will be more reliably reduced and the resin will stay in that area.

The concavo-convex member 7 may be fixed as in this embodiment, but it may also be attached so that it can tilt, or it may be constructed so that only the protrusions can go in and out from the resin molded surface.

Also, in order to more reliably prevent the molten resin from leaving the fixed mold and hanging down toward the skin material, the main body of the resin molding surface of the fixed mold 2 should not be vertical, but should be tilted as appropriate. desirable. For this reason, although it depends on the shape of the mold, the mold mating surfaces are usually inclined.

In addition, if it is not desirable to tilt the entire mold because the mold is large, at least this resin adhesive surface should be made into a single or zigzag slope, or it can be partially swung. It is recommended that the surface be kept movable.

After the injection of the molten resin 9 is completed, as shown in FIGS. 3 and 4, the movable weir member 5 blocking the molten resin
At the same time, the movable mold is moved forward to close the mold, cool for a predetermined period of time, and then open the mold to take out the product.

Note that the configuration of the present invention is not limited to the above-mentioned embodiments, and can be applied to molding machines other than injection molding machines, such as extrusion molding machines and other various molding machines, and there are no limitations on the shape of the mold, etc. Without limitation, it may be a fixed mold or a core, a movable mold or a cavity, and the shape of the movable weir member can be a hinge type, a rotary type, a swing type, a compound movement type, and As an actuator for controlling its position or attitude, in addition to the links and hydraulic cylinders mentioned above, various types of cylinders or electromagnetic solenoids, direct drive systems using linear motors, etc., systems using screws and motors, etc. can be adopted. It is also recommended to link the opening and closing movements of the mold, and the arrangement and number of movable weir members can be changed as necessary. The present invention encompasses all embodiments and modifications that can be easily figured out by those skilled in the art from the above description within the scope of its purpose.

[Effects of the Invention] Since the present invention is constructed as described above, in accordance with the present invention, the contact between the molten resin and the skin material is started and completed within an extremely short period of time when the mold is closed. Uniform contact is achieved at low pressure over the entire surface, resulting in a homogeneous composite molded product.

[Brief explanation of drawings]

1 to 4 are sectional views showing the state of each part of the mold at each step when obtaining a molded product using the mold according to the present invention, and FIG. 1 is a sectional view of the movable mold. Figure 2 is a cross-sectional view showing the state in which the movable dam member has been pulled away from the fixed mold and a skin material has been pasted on its surface. A sectional view showing the state in which the movable weir member is attached to and held on the resin molding surface, Fig. 3 is a sectional view showing the state in which the movable weir member is retracted to the retracted position, and Fig. 4 is a sectional view showing the state when the mold is closed and cooled. It is. 1... Injection molding machine Fixed side mold Resin molding space Gate Fixed mold Hydraulic cylinder Movable weir member Link Uneven member Skin material Molten resin 2 a ・ 2 b ・ 3 ・ ・ ・ 4 ・ ・ ・ 5 ・ ・ ・ 6 ・ ・・ 7 ・ ・ ・ 8 ・ ・ ・ 9 ・ ・ ・ Patent applicant (3] 2) Mitsui Toatsu Chemical Co., Ltd. Figure 1 Figure 3 Figure 2 Figure 4

Claims (1)

[Claims] 1. A gate (2b) for injecting molten resin into the resin molding space.
), and a movable mold (3) that is provided so as to be able to move toward and away from the fixed mold. In a molding mold used for supplying molten resin to form a composite molded body, the fixed mold (2) is provided with the gate so as to be able to move in and out of the molding space, and protrude into the molding space. (2b) to block the passage of the resin injected into the molding space at a close distance from the opening of the gate (2b); A movable weir member (5) that can reciprocate between a retracted position forming a part of the mold surface, and the movable weir member (5)
) is provided with a drive device (4, 6) for causing reciprocating movement between the dam position and the retracted position. 2. The mold for molding a composite molded body according to claim 1, wherein the movable weir member reciprocates in a straight line approximately along its main axis direction. 3. The mold for molding a composite molded body according to claim 1, wherein the movable weir member rotates relative to the fixed mold. 4. The mold for forming a composite molded body according to claim 1, wherein the movable weir member performs a compound movement consisting of parallel movement and rotational movement relative to the fixed mold. 5. Claims 1 to 6, wherein a projection (2c) for preventing the injected molten resin from dripping is provided on the wall surface of the molding space of the fixed mold.
The mold for forming a composite molded article according to any one of the above.