JPS61148020A - Manufacture of tube container made of synthetic resin - Google Patents

Abstract

PURPOSE:To make a quality favorable by improving molding accuracy, by a method wherein a cylindrical parison is made to expand at an inside wall of a cavity to which a pressing core is pushed by extending the same while softness is being kept on. CONSTITUTION:A cylindrical parison which is made to heat at a necessary temperature and soften is extruded within a released mold 1 and the mold 1 is clamped when the parison comes to an appropriate length. Then an opening part of the mold 1 into which the cylindrical parison has been inserted is made to face to the pressing core 11 of the molding device 5 and the tip of a compression molding cylinder 9 is moved until it is abutted against the top of the mold 1 by making a drive-in cylinder 6 act. The parison is inflated by blowing air into the parison through a blowing opening 8 of the compression molding cylinder 9 which is made to adhere closely to an inner wall of each of cavities 2a, 4 of a trunk part mold 2 and cap part mold 3. Then the parison P stuck to the inner wall of a cap part molding cavity 4 is pushed to the inner wall from the inside of the parison by the pressing core 11 by extending the pressing core 11 while softness of the parison P which has been made to inflate is pressed thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a method for manufacturing a synthetic resin tube container with a mouth suitable for use in containing cosmetics, foods, medicines, etc.

"Prior Art" Various methods are conventionally known as methods for manufacturing this type of tube container.

For example, as disclosed in Japanese Patent Publication No. 37-1987, a cylindrical body is formed in advance from a flexible resin material, and this body is inserted into a mold. A method of manufacturing a tube container by injection molding the mouth part and integrating it with the body part by fusion,
Alternatively, as shown in Japanese Patent Application Laid-Open No. 55-118834, after a piece with a mouth part is injection-molded into a cylindrical shape with a bottom and is heated in advance, the mouth part is assembled into a blow mold.
The body part of the piece is stretched in the axial direction using a stretch rond, and then stretched in the radial direction using blow molding.
A method for manufacturing a tube container with two mouths is given below.

``Problems to be solved by the invention'' However, in the former case, in such conventional manufacturing methods, there is a process of accurately positioning and inserting the cylindrical body in the mold, and a process of inserting the mouth part by injection molding. Since the process of forming and integrating the body with the body is required, there is a problem that the manufacturing process and the equipment required therefor become complicated, resulting in high costs. In addition, in the latter type of blow molding, there is a problem that it is difficult to make the wall thickness of the mouth part (mouth part) uniform. In the method of manufacturing a molded product with a structure in which a cylindrical parison is expanded in a cough mold to seal one spout, it is important to keep the wall thickness of this spout constant. The wall may be too thin and break easily, or the hole may not be made when cutting the tip of the spout to open the spout.

The present invention effectively solves these problems and also provides 1.
An object of the present invention is to provide a method for manufacturing a synthetic resin tube container that can maintain constant wall thickness at the mouth, improve quality, and reduce costs.

"Means for Solving the Problems" The present invention provides a mold for a tube container having a cavity for molding a mouth portion, and a pressing core having a shape corresponding to the cavity, which is arranged so as to be expandable and retractable in the axial direction of the mold. When the pressing core is in the contracted state, the cylindrical parison is expanded in the iron so that it comes into close contact with the inner wall of the cavity, and then, while the parison has a softening property, the pressing core is stretched. and press it back onto the parison that is tightly attached to the inner wall of the mouth molding cavity.

Thereafter, the mold was opened m and the molded product was removed from the mold.

"Embodiment" An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. In these figures, reference numeral 1 denotes a mold for a tube container used when carrying out the manufacturing method of one embodiment, and a body mold 2 for molding the body of the tube container.
and a mouth mold 3 for molding the mouth 115 (mouth part and shoulder part). The body part mold 2 and the mouth part metal part 1jIi3 are both formed into two halves, and can be freely approached and separated in the horizontal direction by means of a tightening groove (m), not shown in the drawings.
A mouth mold 3 constituting the bottom of the mold 1 is provided with a mouth molding cavity 4 that forms the mouth of the tube container. That is, for this mouth mold 3.

A cavity 41 for molding a mouth portion having a thread on its outer surface and a shoulder molding cavity 4b for forming a shoulder portion are respectively formed.

In addition, a molding device 5 used when implementing this manufacturing method
An example will be explained with reference to FIG. 1. In this case, a compression molding cylinder 9 having a compressed air blowing port 8 at the tip (lower end) is attached to the rod 7 of the driving cylinder 6. A pressing core 11 is provided at the tip of the rod 10. The pressing core 11 is configured to be expandable and retractable within the mold 1 by the compression molding cylinder 9, and corresponds to the mouth molding cavity 4.

A small diameter cylinder portion 11b that fits into the cavity 4a of the r3 head protrudes from the tip of the large diameter cylinder 1B111. In addition.

A tapered surface 110 is formed between the large diameter cylindrical portion 1111 and the small diameter cylindrical portion 1111b, and at the tip of the small diameter cylindrical portion 11b, a protruding portion lid having an even smaller diameter than the cylindrical portion 11111b is provided. Cooling water is also circulated inside the pressing core 11 through a pipe 12 provided on the rod 10 of the EE# molding cylinder 9.

Next, a mold 4 and a molding device 5 configured as described above
An embodiment of the method of manufacturing a tube container using the metal molding machine will be explained with reference to FIG. Extrude the parison and tighten the gold A11 when it reaches the appropriate length. Next, the opening of the gold fi1 into which this cylindrical parison has been inserted is made to face the pressing core 11 of the molding device 5, and the driving cylinder 6 is operated so that the tip of the compression molding cylinder 9 comes into contact with the upper end of the gold fi1. Move up to. Then, air is blown into the parison from the air inlet 8 of the compression molding cylinder 9 to inflate it, and the cavities 2a of the body mold 2 and the mouth mold 3 are filled.
Place it in close contact with the inner wall of 4.

Thereafter, while the expanded parison P has a softening property, the pressing core 11 is stretched, and the pressing core 11 presses the parison P that is in close contact with the inner wall of the mouth molding cavity 4 from the inside thereof. By this operation, the mouth molding cavity 4
Since the parison P that is in close contact with the inner wall of the parison P is pressed with uniform pressure, its wall thickness becomes uniform and the crimping of this part is improved. As shown in FIG. 2, if the protruding portion lid at the tip of the pressing core 11 is pressed while being slightly separated from the inner wall of the cavity 4, a molded product with a structure in which the spout at the spout is sealed can be molded. ,Also.

As shown in FIG. 3, the protruding portion lid is inserted into the cavity 4.
If it is still in contact with the inner wall of the mold, a molded product with an open spout can be formed.

In addition, in this embodiment, the pressing core 11 is water-cooled with cooling water and cools the parison P that is in close contact with the inner wall of the mouth molding cavity 4 from the inside, so that it is possible to accelerate hardening and improve the molding speed. be.

And gold A! ! After the parison P expanded in the mold 1 is cooled and hardened, the mold 1 is opened deaf and the tube container is removed, and the above operations are repeated to perform molding.

In addition, in the above-mentioned embodiment, the gold W1 having a normal two-sided structure was explained as an example, but the mold 1 is not limited to such a structure, and the present invention is not limited to the structure of the mold. It's not something you can do.

"Effects of the Invention" As explained above, the present invention provides the following excellent effects.

(a) Since the pressing core allows the mouth of the tube container to have a desired size and uniform thickness, it is possible to improve molding accuracy and improve quality.

(b) By adjusting the amount of expansion and contraction of the pressing core, it is possible to punch out the spout at the tip of the pressing core, or to mold it in a sealed state. Tendo production is possible in this way, and costs can be reduced.

(C) When the pressing core is cooled with cooling water, the expanded parison can be cured more quickly and the molding speed can be improved.
Can be blow molded in a fast cycle.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a partially cutaway front view showing a molding device and a row of molds for carrying out a mourning method according to an embodiment of the present invention, and FIG. FIG. 3 is a cross-sectional view shown for explaining the process of the example. l...Mold, 2...Body mold, 3...
... Mouth mold, 4 ... Cavity for mouth molding, 4 m ... Cavity for mouth molding % 4b
... Cavity for shoulder molding, 5 ... Molding device, 6 ... Driving cylinder, 7 ...
・Rod, 8...Inlet, 9...Compression molding cylinder, 10...Rod, 11...
...Press core, 11a...Large diameter cylinder part, 11b
・・・・・・Small diameter cylindrical part, IIC・・・Tapered surface,
11d... Protrusion, 12... Pipe. P...Parison.

Claims (1)

[Scope of Claims] (1.) A cylindrical parison heated and softened to a required temperature is inserted into a mold of a tube container having a cavity for molding the mouth, and the mold is clamped, and the parison is Air is injected into the cavity and the parison is expanded so that it comes into close contact with the inner wall of the cavity.Then, while the expanded parison still has softening properties, it can be expanded and contracted in the axial direction within the mold, and is used to form the mouth of the mold. The method is characterized in that a pressing core having a shape corresponding to the cavity is stretched and pressed against a parison that is in close contact with the inner wall of the mouth molding cavity, and then the mold is opened and the molded product is taken out from the mold. A method for manufacturing a synthetic resin tube container. (2.) Cooling water is allowed to flow inside the pressing core to cool the pressing core while pressing it against the parison that is in close contact with the inner wall of the mouth molding cavity. A method for manufacturing a synthetic resin tube container.