JPH0565105A - Disposing method for film in tension - Google Patents

Abstract

PURPOSE:To make it possible to place a film under a tightly stretched condition for a method to provide a film on the edge of a container after molding by fitting a film for sealing in a molding die previously, when a frame body is injection-molded in a molding die. CONSTITUTION:A groove 29 is formed on either one of an upper die 15 and a lower die 19 which constitute a molding die, and a protuberance 31 is formed on the other die, and a film is fitted by gripping the film by both dies. Also, the surface which comes into contact with the film on the peripheral edge of a frame body is made to be a protruding curved surface (therefore, the surface of the lower die is made to be a recessed curved surface 25) so that the film is stretched.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of stretching a sealing film on a container or the like, and more particularly, when a container or the like is molded by injection-filling a molten resin with molten resin, The present invention relates to a method in which a film is attached in advance and the stretching is performed.

[0002]

2. Description of the Related Art A film (so-called virgin film) for sealing a container is provided on a container made of a resin or a frame constituting an edge portion of the container. For example, in a compact cosmetic container, a synthetic resin film, which is the virgin seal, is provided on the peripheral edge of a middle plate container containing a cosmetic.

The conventional method of providing such a virgin film is to mount a virgin film in a mold for molding a container or the like in advance, and then inject a molten resin for molding the container or the like into the mold. By doing so, the film is stretched at the same time when the container or the like is molded.

[0004]

However, in the above-mentioned conventional method, the stretched film sometimes becomes loose. When the slack is obvious and occurs in one direction, there is a possibility that it may become a wrinkle-like state.

The present invention has been made to solve the above problems, and it is a technical object of the present invention to provide a film tensioning method capable of tensioning a sealing film in a tensioned state (extended state). And

[0006]

In order to solve the above technical problems, the present invention has the following constitution. That is,
In the film tensioning method, in which a film for sealing is mounted in advance in a mold for a container or a frame, and a molten resin is injected and filled to stretch the film around the peripheral edge of the container or the frame. A groove is provided on one of the upper mold and the lower mold that form the mold, and a protrusion is formed on the other, and the film is engaged by the protrusion and the groove to perform the mounting, and the surface of the peripheral edge that contacts the film. Is a method of stretching a film with a convex curved surface.

[0007]

When the upper mold and the lower mold constituting the mold are set by previously mounting the film in the mold, the film is caught by the protrusion and the groove. During this biting, the film can be pulled and taut. Furthermore, the surface of the peripheral edge of the container or frame contacting the film is a convex curved surface,
When the molten resin is injected and filled, the film tends to be pulled and further taut on the convex curved surface.

[0008]

Embodiments of the present invention will be described with reference to FIGS. FIG. 2 is a vertical cross-sectional view of the frame body 3 provided in a part of the inner dish container 1 provided inside the compact cosmetic container. A sealing film 5 called a virgin film is provided on the upper surface of the frame body 3.

The frame 3 shown in FIG. 3 is an enlarged view of the main part of FIG.
The upper surface of slops toward the inner edge, and this sloping surface is a convex curved surface 7 and continues to a position corresponding to the back side surface of the frame body 3. The film 5 is attached along the convex curved surface 7.

FIG. 4 is a vertical sectional view of a molding die 9 for molding the frame 3 of FIG. The upper die 11 that constitutes the molding die 9 includes a cylindrical central upper die 13 and a ring-shaped peripheral upper die 15. The lower die 17 is composed of a cylindrical lower central die 19 and a ring-shaped peripheral lower die 21.

FIG. 1 is an enlarged view of the main part of FIG. A cavity 23 (a hollow surface in which a molten resin is injected and filled) 23 processed according to the shape of the frame 3 in which the molding is performed gathers the center upper mold 13, the center lower mold 19, and the peripheral upper mold 15. Is formed in part. In the figure, the shape of the cavity 23 corresponds to the shape in which the frame 3 is upside down.
The gap 11 between the center upper mold 13 and the center lower mold 19 for inserting the film 5 is 0.08 mm.

The peripheral edge of the frame 3 and the surface corresponding to the surface in contact with the film 5 (the upper surface of the frame 3 in FIG. 3) is the upper surface of the central lower mold 19, and the convex curved surface 7 is formed on the frame 3. To form a concave curved surface 25.

Further, an injection hole 27 for injecting and filling molten resin into the cavity 23 is provided in the central upper mold 13. A portion near the cavity 13 where the upper peripheral die 13 and the lower peripheral die 19 contact each other, that is, the film 5
A ring-shaped groove 29 is formed in the upper peripheral die 13 at a portion where the peripheral portion is sandwiched. The lower surrounding mold 19
A ring-shaped protrusion 31 is formed on the. This protrusion 3
1 is in a position to be fitted in the groove 29. Groove 29 and protrusion 3
There is a gap between 1 and the inner gap 12 is 0.15 mm.
The dimension l3 of the tip portion of the protrusion 31 is 0.7 mm, and the outer gap l4 is 0.15 mm. The gap 15 at the tip of the protrusion 31 is 0.3 mm,
The height 16 of the protrusion 31 is 0.5 mm.

In the present embodiment, the procedure for providing the film 5 on the frame 3 is as follows. That is, first, the film 5 is placed on the lower center mold 19. At this time, the periphery of the film 5 is in a state of slightly protruding from the lower center mold 19 to the outside. In this state, the lower peripheral die 21 is set so as to cover the lower central die 19 from above. As a result, the peripheral edge of the film 5 is partially sandwiched between the central lower mold 19 and the peripheral lower mold 21. In this state, the upper peripheral mold 15 is set. At this time, the groove 29 and the protrusion 31 are fitted to each other, and the film 5 is caught between them. By this bite, the film 5 is pulled outward (arrow in FIG. 1).

Next, the center upper mold 13 is set. A cavity 23 is formed by this set. Then, molten resin is injected and filled into the formed cavity 23 through the injection hole 27. The setting of the center upper mold 13 and the injection filling may be performed at the same time. At this time, the lower center mold 19 pushes the film 5 upward in the figure, and the surface of the frame 3 formed pushes the film 5 downward in the figure. Since these pushing forces act on the convex curved surface 7 of the frame body 3 (that is, the concave curved surface 25 of the lower central mold 19), the film 5 is given an outward pulling force (arrow in the figure) as if it were trying to shift.

After the frame 3 is formed in this manner, the peripheral edge of the film 5 is cut off by a cutter.
Most of all, when adopting a method in which the upper die and the lower die are combined and molded at the same time as injection filling, a cutter is provided in the upper die and the lower die so that cutting can be performed continuously after the molding operation. Good.

As described above, according to this embodiment, the groove 29
The end portion of the film 5 is caught between the protrusion 31 and the protrusion 31, and the convex curved surface 7 of the frame 3 to be molded causes the film 5
Is stretched, the film 5 in a taut state is stretched on the frame body 3 after molding, and the conventional slack (two-dot chain line in FIG. 2) does not occur.

Further, although the groove 29 and the protrusion 31 are provided in a ring shape in the above-mentioned embodiments, they can be provided only in a part instead of a ring shape in other embodiments. For example, it may be partially discontinuous.

The frame 3 is, as shown in FIGS.
The tongue piece 33 for peeling off the film 5 may be provided. That is, a tongue piece 33 is provided on the outside of the frame body 3, and the thickness between the tongue piece 33 and the frame body 3 is thin (see FIG. 7). When the piece 33 is lifted upward, the tongue piece 33 is broken, and by further lifting the tongue piece 33, the film 5 is peeled off and the cosmetic material of the medium dish container 1 can be used. In such an embodiment, the groove 29 and the protrusion 3 provided in the molding die 9
It is also possible to provide 1 in only the portion of the periphery of the frame body 3 where the tongue piece 33 is not formed.

[0020]

As described above, according to the film tensioning method of the present invention, when the container or the frame is molded, the film is caught by the groove and the projection, and the film is pulled by the convex curved surface. It can be in a stretched state by being stretched.

[Brief description of drawings]

FIG. 1 is an enlarged view of a main part I of a cross section of a molding die used in a film tensioning method according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view of an entire frame body molded by the molding die of FIG.

FIG. 3 is an enlarged view of a main part III in FIG.

FIG. 4 is a vertical cross-sectional view showing the entire molding die of FIG.

FIG. 5 is a plan view of a frame body according to another embodiment.

FIG. 6 is a vertical cross-sectional view of FIG.

7 is an enlarged view of a main part VII of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Medium plate container 3 ... Frame body 5 ... Film (virgin film) 7 ... Convex curved surface 9 ... Mold 13 ... Center upper mold 15 ... Perimeter upper mold 19 ... Central lower mold 21 ... Perimeter lower mold 23 ... Cavity 29 ... Groove 31 ... Protrusion

Claims (1)

[Claims] 1. A film stretcher for tensioning a film around a peripheral edge of the container or the frame by preliminarily mounting a sealing film in a mold for the container or the frame and injecting and filling a molten resin. In the method, a groove is provided on one of the upper die and the lower die that form the forming die, and a protrusion is formed on the other die, and the film is engaged by the protrusion and the groove to perform the mounting, and the peripheral edge. The film tensioning method, wherein the surface in contact with the film is a convex curved surface.