JP2637197B2 - Container body and press device - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a plastic container body having a flange portion and a press device used for manufacturing the same.

(Prior Art) There are various types of metal containers, for example, metal cans, which can be classified into three-piece cans and two-piece cans depending on the structure of the can body. The three-piece can is also called a pre-tin solder can and has a structure in which a cylindrical body, a lid, and a bottom are sealed by double winding.

On the other hand, a two-piece can is also called a tin punched can, and has a structure in which a body and a bottom (container main body) are integrally formed and a lid is double-sealed.

These metal cans are used as containers for food cans, juices, soft drinks, jams, dried foods and the like as food packaging containers, and are rigid containers with particularly excellent sealing and storage functions. However, the metal can has the following points to be improved. That is, since it is a metal can, there is a limit to weight reduction.

Once impacted, once collapsed, there is no resilience and it will be deformed.

Energy costs in manufacturing are higher than those of plastic containers.

When the display effect of the container exterior is made of metal, it cannot be freely changed, and the exterior means is only by printing.

It is impossible to make a transparent container that allows the contents to be checked without opening the can.

In order to solve such a disadvantage of the conventional metal can, a container with a metal lid in which a metal lid is attached to a plastic container body is considered.

Further, as a method of manufacturing a plastic container body, a plastic sheet having a thickness necessary for forming a container is heated by a general thermoforming method, and a container having a flange portion is formed by a general molding method using a mold. A method has been considered in which a molded product of the main body is formed (sheet forming), the thickness of the flange portion is reduced, and the width of the flange portion is cut to a predetermined width.

In this method, a pressing device is used in a pressing process for reducing the thickness of the flange portion, and a cutting device is used in a cutting process for cutting the width of the flange portion to a predetermined width.

(Problems to be Solved by the Invention) As described above, a container with a metal lid in which a metal lid is attached to a plastic container main body instead of the conventional metal can is considered.

In this case, the container body is provided with a flange portion provided on the periphery of the upper end opening of the body portion, and a container with a metal lid is obtained by winding the periphery of the metal lid around the flange portion.

By the way, when the peripheral portion of the metal lid is wound around the flange portion of the container body as described above, it is convenient in manufacturing a container with a metal lid if it can be easily wound.

The present invention has been made in view of the above points, and provides a container body capable of easily performing a tightening operation when manufacturing a container with a metal lid, and a press device used for manufacturing the container body. The purpose is to do.

[Configuration of the invention]

(Means for Solving the Problems) The present invention relates to a plastic container main body provided with a flange protruding outward in the radial direction on the periphery of an upper end opening of a body, wherein a circle is formed at a base end of a lower surface of the flange. A container main body characterized by forming an annular concave portion extending in the circumferential direction, and a press fixing plate abutting on the upper surface of the flange portion of the plastic container main body formed by sheet forming,
An annular plug movably disposed with respect to the press fixing plate and provided with an annular plug that abuts on a lower surface of the flange portion, wherein an annular projection extending in a circumferential direction is provided inside an abutting surface of the annular plug, A press device used for manufacturing the container body, wherein an annular concave portion is formed at a bottom end portion of a lower surface of the flange portion.

(Operation) According to the present invention, since the annular concave portion extending in the peripheral direction is formed in the base surface of the lower surface of the flange portion of the container body, the flange portion is easily bent by the annular concave portion and the peripheral edge of the metal lid is easily formed. Can be wrapped around. Further, since an annular projection extending in the circumferential direction is provided inside the contact surface of the annular plug of the press device, an annular concave portion is formed at the base end of the lower surface of the flange portion when the flange portion of the plastic container body is pressed. Can be formed.

(Example) Hereinafter, an example of the present invention is described with reference to drawings.

 1 to 7 show an embodiment of the present invention.

First, the container body according to the present invention will be described with reference to FIG. As shown in FIG. 6, the container body 10 includes a body 11 having an upper end opening, and a flange portion 13 provided on the periphery of the upper end opening of the body 11 and protruding outward in the radial direction. Is made of plastic as a whole.

The flange portion 13 has an upper surface 13a and a lower surface 13b, and an annular concave portion 14 extending in the circumferential direction is formed at a base end of the lower surface 13b of the flange portion 13.

The flange portion 13 of the container body 10 having such a configuration
Next, by winding the peripheral portion 17 of the metal lid 16 around, a container with a metal lid as shown in FIG. 7 is obtained.

In this case, since an annular concave portion 14 extending in the circumferential direction is formed at the base end of the lower surface 13b of the flange portion 13, the flange portion
The portion 13 is easily bent at the annular concave portion 14. For this reason, the flange 13 of the container body 10 and the peripheral
17 can be easily wound.

Next, a method of manufacturing the plastic container body having the above-described configuration will be described.

First, with reference to FIG. 5, a process for producing a molded article of a container body by thermoforming by general sheet forming will be described.

That is, a plastic sheet 30 having a thickness necessary for forming a container is heated by a heater 41, and a molded article 20 including a plurality of container bodies 10 is molded by a general molding method using a mold. The molding method may be any of pressure forming, vacuum forming, or a combination thereof.

The body 11 of each container body 10 constituting the obtained molded article 20 has a thickness and a strength enough to withstand the pressure applied during double tightening. However, the thickness of the flange portion 13 is too large, and is not suitable for double winding. Therefore, a pressing step of the flange portion 13 is required.

The plastic sheet 30 forming the container body 10
When a food storage container is manufactured, a plastic laminated sheet configured to reduce the permeability of oxygen gas and water vapor is used. As a food storage container, the oxygen gas barrier property of the container is 0.8cc / 100cc · 24hrs.atm (20 ℃, 90 ℃
% RH) or less and, H ₂ O barrier 0.2g / 100cc · 24hrs.atm
(40 ° C., 90% RH) or less.

Next, the container body 10 constituting the molded product 20 is roughly separated one by one, and then the thickness of the flange portion 13 is reduced (pressing process), and the width of the flange portion 13 is set to a predetermined width (cutting process). The container body 10 shown in FIG. 6 is obtained.

Such a plus step and a cutting step of the flange portion 13 will be described with reference to FIGS.

As shown in FIGS. 1 to 3, a press device for performing a pressing step includes a press fixing plate 21 on which a plastic container main body 10 is placed in a repeated state, and a press fixing plate 21 disposed above the press fixing plate 21 in a vertical direction. And an annular plug 23 which is movable.

Further, the press fixing plate 21 is provided with a fixed contact surface 22 that contacts the flange upper surface 13a of the container body 10, while the annular plug 23 has a plug contact surface that contacts the flange lower surface 13b of the container body 10. A contact surface 24 is provided. Further, a heater 25 is wound around the outer periphery of the press fixing plate 21 to heat the press fixing plate 21. Similarly, a heater 26 is wound around the outer periphery of the annular plug 23.

An annular projection 27 extending in the circumferential direction is provided inside the plug-side contact surface 24 of the annular plug 23.

 This annular projection 27 will be described with reference to FIG.

The annular projection 27 has a semicircular cross section, while a curved surface 28 is formed on the fixed-side contact surface 22 of the press fixing plate 21 in correspondence with the annular projection 27. The radius of the curved surface 28 is 7 to 8 times the radius of the annular projection 27. The annular projection 27 and the curved surface 28 form an annular recess 14 extending in the circumferential direction at the base end of the lower surface 13b of the flange portion of the container body 10.

The distance between the fixed-side contact surface 22 and the plug-side contact surface 24 is larger toward the outside (to the left in FIG. 3). For this reason, since the surplus portion of the flange portion 13 escapes to the outside during the pressing process, the press can be performed with high accuracy without the surplus portion protruding inward and forming a dango-shaped mass.

 Next, the pressing process will be described.

The container main body 10 separated from the molded product 20 has a male mold 29 having a shape corresponding to the container main body 10 mounted therein, and is placed on the press fixing plate 21 with the flange portion 13 downward.

Subsequently, the annular plug 23 descends from above, and presses the flange 13 between the fixed-side contact surface 22 of the press fixing plate 21 and the plug-side contact surface 24 of the annular plug 23 while heating and presses the flange 13. The thickness of 13 is a predetermined thickness. The driving of the annular plug 23 may be hydraulic or pneumatic.

When the flange portion 13 has a predetermined thickness, the annular plug 23 is raised, and the pressing of the flange portion 13 by the pressing step is completed.

By such a pressing step, the thickness of the flange portion 13 is reduced to a predetermined value, and the annular concave portion 14 extending in the circumferential direction is formed at the base end of the flange portion lower surface 13b.

It is preferable that the thickness t of the flange portion 13 be 0.25 to 0.9 mm.

Also, the initial thickness of the flange portion 13 and t _o, the case where the thickness after pressing was t _1, it is preferable 0.9t is ₀ ≧ t ₁ ≧ 0.4t _0.

More preferably, 0.9t ₀ ≧ t ₁ ≧ 0.6t ₀ .

That is, when t ₁ ≧ 0.9t ₀ , the thickness of the flange portion 13 is too large, and the unevenness of the thickness of the flange portion 13 cannot be sufficiently corrected, which is not suitable for double winding.

When t ₁ ≦ 0.4t ₀ , the flange 13 protrudes too much because it is too crushed. For this reason, a dango-shaped lump is formed around the pressing portion, and the thickness of the flange portion 13 varies due to thermal deformation.

Since the male mold 29 is mounted in the container body 10 during the pressing step, stable positioning of the container body 10 can be performed, and pressing can be performed with high accuracy. Further, since a part of the pressed flange can be prevented from protruding inside the container body 10 and forming a dango-shaped mass,
The shape of the container body 10 is not deformed by the pressing process.

Next, the container body 10 is cooled for a certain period of time, and thereafter cut by the cutting device shown in FIG. 4 so that the width of the flange portion becomes a predetermined width.

The cutting device includes a cut fixing plate 36 and a cylindrical cutter 38 which is disposed above the cut fixing plate 36 and is movable in the vertical direction.

The container main body 10 is equipped with a male mold 37 having a shape corresponding to the container main body 10 inside, and a cut fixing plate with the flange portion 13 downward.
Placed on 36.

In this case, the container body 10 is vacuum-fixed to the male mold 37 by the ventilation pipe 37a formed in the male mold 37.

Subsequently, the cutter 38 descends from above and punches the flange portion 13 between itself and the peripheral edge of the cut fixing plate 36, and the width of the flange portion 13 is set to a predetermined width.

Generally, the width of the flange portion 13 is preferably 1.0 to 2.5 mm.

Since the male mold 37 is mounted in the container body 10 during this cutting step, the container body 10 can be stably positioned on the cut fixing plate 36. For this reason, the flange part is accurately
13 can be cut.

In the above embodiment, a cooling pipe is provided inside the male mold 29 of the press device and the male mold 37 of the cutting device, and the male mold 2 is provided.
9,37 may be cooled. In this case, it is possible to prevent heat from being transmitted to the entire container body 10 in the pressing step and the cutting step, so that deformation of the container body 10 can be reliably prevented.

〔The invention's effect〕

As described above, according to the present invention, since the annular concave portion extending in the circumferential direction is formed at the base end of the lower surface of the flange portion of the container body, the flange portion is easily bent by the annular concave portion. For this reason, the periphery of the metal lid can be easily and reliably wound around the flange portion. Further, since the annular projection extending in the circumferential direction is provided inside the contact surface of the annular plug of the press device, the annular concave portion can be easily formed at the base end of the lower surface of the flange portion during the pressing step.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 7 are views showing an embodiment of a container body and a press device according to the present invention. FIG. 1 is a sectional view showing the press device, and FIG. 2 is FIG. FIG. 3 is an enlarged view of part A, with the container body removed for convenience, FIG. 3 is an enlarged view of FIG. 2 part B, FIG. 4 is a sectional view showing a cutting device, and FIG. 5 is a container formed by thermoforming by sheet forming. FIG. 6 is a cross-sectional view showing a container main body, and FIG. 7 is a sectional view showing a container main body. FIG. 7 shows a container with a metal lid formed by winding a peripheral portion of a container with a metal lid around a flange of the container main body. FIG. 10 ... container body, 11 ... trunk, 13 ... flange, 14 ...
… Annular recess, 21… Press fixing plate, 22… Fixed side contact surface, 23… Annular plug, 24… Plug side contact surface, 27…
Annular protrusion.

Claims (2)

(57) [Claims] 1. A plastic container body provided with a flange protruding outward in the radial direction at a peripheral edge of an upper end opening of a body portion, wherein an annular concave portion extending in a circumferential direction is formed at a base end of a lower surface of the flange portion. A container body characterized by the above. 2. A press fixing plate abutting on an upper surface of a flange portion of a plastic container body formed by sheet forming, and an annular plug movably disposed on the press fixing plate and abutting on a lower surface of the flange portion. In the press device provided, inside the contact surface of the annular plug,
The press device used for manufacturing a container body according to claim 1, wherein an annular protrusion extending in a circumferential direction is provided, and an annular concave portion is formed at a base end portion of a lower surface of the flange portion.