JPH0375020B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for molding a composite molded product consisting of a primary molded product by injection compression molding and a secondary molded product by injection molding.

[Prior Art] Rubber stoppers used for medical and pharmaceutical purposes are generally required to have appropriate elasticity to maintain airtightness and chemical resistance at the part that comes into contact with the packaged drug solution. A rubber stopper laminated with a film made of fluororesin or the like is widely used.

As a molding method, as disclosed in Japanese Patent Application Laid-Open No. 57-47637 and Japanese Patent Publication No. 57-53184,
The rubber stopper is molded in two parts: the large head and the bottle mouth insertion part, and when the bottle mouth insertion part is primarily formed, a resin film is stretched over the opening of the cavity.
A rubber sheet is press-fitted into the cavity from above the resin film under pressure, so that when the bottle opening insertion part is formed, the resin film is laminated except for the top surface of the bottle opening insertion part.

[Problems to be solved by the invention] In the above conventional method, the rubber stopper, which should originally be one piece, is
Because the molding is done in two parts, and the resin film must be punched out during molding, the molding and other molding processes become complicated, and the yield rate of expensive resin films such as fluororesin is poor, making it uneconomical and costly. There were problems such as.

Therefore, it is possible to use a multi-color injection molding machine to inject the stopper body and the laminate layer into multiple layers, but injection molding of fluororesin has a limit of wall thickness of about 0.5 mm, and conventional It is extremely difficult to form a laminate layer with a thickness of 0.02 to 0.1 mm, such as by molding with a film.

This invention was devised to solve the above-mentioned conventional problems, and its purpose is to apply the commonly used injection composite molding method to create a laminated resin film. The object of the present invention is to provide a new molding method that allows similar molded products to be obtained.

[Means for Solving the Problems] The feature of the present invention according to the above object is that a plurality of fixed molds having different cavity shapes are arranged, and a movable mold of the same structure is used to alternately close the molds with the fixed molds. The primary molded product attached to the rotating part of the movable platen and injection molded using the movable mold and one fixed mold is transferred together with the movable mold to the other fixed mold, and secondary molding is performed with the primary molded product inserted. When injection molding a product to form a composite molded product consisting of a primary molded product and a secondary molded product, in the cavity on the primary molding side formed by one of the fixed molds and the movable mold,
A pressurizing means is provided that compresses the material by completely varying the volume of the cavity, and the material injected into the cavity on the primary molding side is compression-molded into a thin primary molded product that covers the entire cavity. , to perform injection molding of a secondary molded product on the thin-walled molded product.

This invention will be explained in more detail below with reference to Examples.

[Example] The movable platen 1 is guided by a tie bar 5 provided over a fixed platen 4 having a fixed platen 2 and a mold clamping cylinder 3, and is moved by the mold clamping ram 6 of the mold clamping cylinder 3 connected to the back. It reciprocates with respect to the fixed platen 2.

A rotary plate 7 is provided on the fixed platen 2 side of the movable platen 1, and the rotary plate 7 is rotated by a motor 8 on the back of the movable platen 1. Moreover, the rotary plate 7 has a movable mold 9 at a position symmetrical to the center of rotation on the surface.
10, and on the inner surface of the fixed platen 2 corresponding to the movable molds 9 and 10, a fixed mold 11 for molding a thin-walled molded product and a fixed mold 1 for molding the molded product body.
2 is installed.

Inside the movable molds 9 and 10, a fixed mold 11,
A core mold 13 that completely changes the volume of the cavity on the primary molding side formed by 12, and a hydraulic cylinder 15 and a piston that move the core mold 14 forward and backward relative to the cavity surfaces of the fixed molds 11 and 12. A pressurizing device consisting of 16 is provided.

Furthermore, injection devices 17 and 18 are disposed in each cavity passing through the fixed platen 2, and the injection device 1 is disposed in each cavity.
Reference numeral 7 injects fluororesin material, and injection device 18 injects butyl rubber material.

Next, the molding method will be explained.

First, the movable mold 9 and the fixed mold 11, and the movable mold 10 and the fixed mold 12 are faced and clamped. At this time, the core mold 13 on the movable mold side is moved back to increase the cavity volume. In this state, the fluororesin material 19 is injected from the injection device 17 into the cavity.
The injection amount should be enough to fill part of the cavity.

Next, the pressurizing device is activated to move the core mold 13 forward to completely reduce the cavity volume and compress the fluororesin material to make it thinner (0.1 mm).
It is molded into a primary molded product 20 (below).

When the above molding is completed, the mold is opened after cooling and solidifying. In this case, the primary molded product 20 is not released from the mold and remains attached to the movable mold 19.

After opening the mold, start the motor 8 to rotate the rotary plate 7 by 180 degrees, convert the movable mold 9 into the fixed mold 12, and change the movable mold 1 into the fixed mold 12.
0 are placed opposite each other to the fixed mold 11.

After clamping the mold again, butyl rubber is injected and filled from the injection device 18 into the cavity formed by the movable mold 9 and the fixed mold 12, and is further vulcanized to form a secondary molded product 21 that will become the plug body on one side of the primary molded product 20. to form. At the same time as this molding, the primary molded product 20 is transferred to the secondary molded product 2.
1 is laminated, and a composite molded product is created in which the two are integrated.

Further, in the cavity on the primary molding side formed by the movable mold 10 and the fixed mold 11, a new primary molded product 20 is molded by injection compression molding in the same manner as described above.

When the molding on both sides is completed, the mold is opened again and the molded product is taken out from the secondary molding side. After the mold release is completed, the movable mold 9 is moved to the fixed mold 1 by the rotary plate 7.
1, primary molding and secondary molding are performed in the same manner as above (FIGS. 1 and 2), and then the mold is opened and mold release is performed on the secondary side (FIG. 3). Thereafter, a composite molded product is continuously molded through similar steps.

In the above embodiment, the pressure device is provided on the movable mold side, but the pressure device may be provided on the fixed mold side that forms the cavity on the primary molding side. Also, the molding machine is 2
Although a model having sets of molds in parallel is shown, this may also be a type in which movable molds are provided on the front and back sides of a rotatable movable platen provided between two sets of fixed molds installed oppositely. There are no other limitations on the method of applying compressive force, the molded product, the material, etc.

[Effects of the Invention] As described above, the present invention provides a pressurizing means for compressing material by completely changing the volume of the cavity in the cavity on the primary molding side formed by one of the fixed molds and the movable mold. The material injected into the cavity on the primary molding side by the pressurizing means is compression molded into a thin primary molded product that covers the entire cavity, and the secondary molded product is injection molded into the thin molded product. It is possible to form extremely thin primary molded products of 0.2 mm or less, which was previously thought to be difficult with injection molding, with high precision, and not only is there less material wastage, but
Since compression molding of the primary molded product and injection molding of the secondary molded product can be performed continuously on the same molding machine, productivity is significantly improved and the product has a thinner layer of higher quality than before. It has the advantage of being able to mold composite molded products at low cost.

[Brief explanation of drawings]

The drawings show the injection compression composite molding method according to the present invention, and FIGS. 1 to 3 are schematic vertical sectional views of an injection device showing the steps in order. 1...Movable plate, 2...Fixed plate, 7...Rotating plate,
9, 10...Movable plate, 11, 12...Fixed type, 1
3... Core mold, 17, 18... Injection device, 19...
...Fluororesin material, 20...Primary molded product, 21...
...Secondary molded product, 22...Composite molded product.

Claims (1)

[Claims] 1. A plurality of fixed molds with different cavity shapes are arranged, and a movable mold of the same structure that closes alternately with the fixed molds is attached to the rotating part of the movable platen, and the movable mold and one of the fixed molds The injection-molded primary molded product is transferred together with the movable mold to the other fixed mold, and injection molding of the secondary molded product is performed with the primary molded product inserted, thereby combining the primary molded product and the secondary molded product. When molding a composite molded product, a pressure means is provided in the cavity on the primary molding side formed by one of the fixed molds and the movable mold to compress the material by completely changing the volume of the cavity. Injection compression characterized by compression molding the material injected into the cavity on the primary molding side by a pressure means into a thin primary molded product that covers the entire cavity, and then injection molding the secondary molded product into the thin molded product. Composite molding method.