JPH05229558A - Plastic container with metal lid - Google Patents

Abstract

PURPOSE:To obtain a plastic container with a double wound metal lid which has airtightness as good and sufficient as a metal container. CONSTITUTION:The subject plastic container with metal lid is formed of a plastic container 1 having a flange part 2 for winding a metal lid at a container opening and the metal lid 5 having a peripheral part for forming a winding part 3 together with the flange part 2. In this plastic container 1 with the metal lid 5, the winding thickness T at a time when the metal lid 5 is double wound from an external peripheral direction is within a range of 1.95-2.05mm and the winding width W is within a range of 2.40-2.80mm. According to this method, neither using a special plastic container nor winding means, a plastic container with a double wound metal lid which has airtightness as good and sufficient as a metal container can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double-wrapped plastic container with a metal lid, which is as good as a metal can and has a sufficient sealing property.

[0002]

2. Description of the Related Art Conventionally, tin or metal cans made of aluminum have been used as containers for food cans, but in recent years, plastic molded containers have been increasingly used due to their lighter weight and fashionability. In this case, as a method of constructing the lid, there are cases where a flexible sheet or film made of plastic is heat-sealed, but in order to attach importance to the image of a conventional metal can or to improve retort resistance and opening resistance. A method in which a metal lid made of tin or aluminum and provided with an easy-open property is tightly wound around a plastic container may be used.

As a method of winding and tightening the metal lid on the plastic container, a method of double-winding with a winding roll of a winding machine can be applied as in the conventional metal can. In this case,
Since the flange portion on the container side is made of plastic, rigidity and elastic modulus are factors, and as shown in the front sectional view of the conventional double winding portion and the conventional second winding roll in FIG. Occasionally, the flange portion 2 of the container 1 may escape, or the peripheral edge of the metal lid 5 may bend and return to a portion (hereinafter referred to as a cover hook CH) that bites into the container flange, resulting in a proper overlap amount OL. However, problems such as leakage of contents sometimes occurred.

[0004]

Various proposals have heretofore been made to improve the sealing performance of a plastic container with a metal lid, which is obtained by double-winding a plastic container with a metal lid as described above. However, the conventional improvement plan has a problem in cost because it requires a plastic container having a special flange shape and a special winding device.

Further, none of the conventional techniques has achieved double winding tightening having a good and sufficient sealing property equivalent to that of a metal can.

[0006]

The present invention has been invented in order to solve the above-mentioned problems and does not require the use of a special plastic container or a winding machine as described above. The purpose is to obtain a double-wrapped plastic container with a metal lid that has good and sufficient sealing performance equivalent to a metal can, and the gist thereof is a plastic container that has a flange portion for winding the metal lid in the container opening. And a metal lid having a peripheral edge portion for forming a winding tightening portion between the flange portion and the flange portion when the winding tightening thickness: T is 1.95 to 2. 05mm and winding width: W
Is in the range of 2.40 to 2.80 mm and relates to a plastic container with a metal lid. Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 shows an embodiment of the present invention, FIG. 1 is a front sectional view showing an example of a plastic container with a metal lid of the present invention, and FIG. 2 is a front sectional view showing an example of a metal lid of the present invention. FIG. 3 is a front cross-sectional view of a first winding roll and a winding state for double-wrapping a plastic container with a metal lid according to the present invention, and FIG. 4 is a second winding roll and a front sectional view of a winding state. FIG. 5 is a front cross-sectional view of a conventional double winding section and a conventional second winding roll.

In the present invention, as shown in FIGS. 1 to 4, a plastic container 1 having a flange portion 2 for winding a metal lid at the opening of the container 1 and a winding portion 3 are formed between the flange portion 2 and the plastic container 1. The metal lid 5 having the peripheral edge portion 4 for tightening is double-wound from the outer peripheral direction, and the winding thickness T is 1.95.
.About.2.05 mm, and tightening width: W is 2.40 to 2.
It is a plastic container with a metal lid in the range of 80 mm.

The winding thickness of the plastic container with the metal lid: T is 1.95 to 2.05 mm, and the winding width: W is 2.
It has been found that when the thickness is in the range of 40 to 2.80 mm, a double winding state having a good and sufficient sealing property equivalent to a metal can can be obtained.

The reason for this is that when the winding thickness T of the winding container with a metal lid is made thicker than 2.05 mm, a void occurs inside the winding, and when it is thinner than 1.95 mm, the inside of the winding is compressed too much. It is considered that a good winding state cannot be obtained due to problems such as deformation of the winding inside. Further, when the winding tightening width W is smaller than 2.40 mm, problems such as cutting the flange portion of the container 1 at the tip of the cover hook CH occur, and when larger than 2.80 mm, the return of the cover hook is large and stable. It is considered that the overlap amount cannot be obtained.

The plastic container 1 used in the present invention may be made of a thermoplastic resin material such as polyethylene, polypropylene, nylon, polyester, polyvinyl chloride, polyvinylidene chloride, or the like, and an oxygen barrier resin such as EVOH. It may be a laminated material containing. A plastic container 1 obtained by molding a sheet made of the above-mentioned material by pressure molding, vacuum forming, or the like is provided with a housing portion 11 for housing the contents, and a metal lid winding provided on the upper end of the peripheral wall of the housing portion 11. It is composed of a flange portion 2.

The metal lid winding flange portion 2 is preferably mechanically press-formed into a highly accurate shape. Then, as shown in FIG. 2, its width: WF is 2.0 to 2.5 m.
m, thickness: TF in the range of 0.4-0.7 mm is convenient for obtaining the plastic container with a double-sealed metal lid having the hermeticity of the present invention.

The metal lid 5 used in the present invention is also used.
The shape, the material, etc. are not limited as long as they can be wound and tightened, but a counter sink CS is formed as shown in FIG. 2, and it is preferable that the peripheral portion 4 is curled in advance. The thickness of the aluminum lid is TC
Is 0.28-0.30 mm, thickness for steel lid:
A TC of about 0.23 mm can usually be used.

Next, according to the present invention, when the double tightening is performed from the outer peripheral direction, the tightening thickness: T is 1.95 to 2.05 mm, and the tightening width: W is 2.40 to 2.80 mm. A method for manufacturing a plastic container with a metal lid as in range is described.

As shown in FIGS. 2 to 4, the metal lid 5 is placed on the metal lid winding flange portion 2, and the metal lid counter sink CS is supported from the inside by the chucking roll 8 while the first winding is performed. The cover hook CH is formed by further bending the curled peripheral edge portion 4 of the metal lid 5 from the outside by the tightening roll 6, and the metal lid winding flange portion 2 is formed.
Engulf to tie each other.

Next, the peripheral portion 4 of the metal lid 5 is further pressed from the outside by the second winding roll 7 to bring the metal lid winding flange portion 2 into close contact with the peripheral portion 4 of the metal lid 5, Get the double winding state.

The first winding roll 6 and the second winding roll 7 are, as shown in FIGS. 3 and 4, a plastic container 1 having a flange portion 2 for winding a metal lid in the container opening, and Roll grooves 61 and 71 are formed for fastening the metal lid 5 having the peripheral edge portion 4 for forming the winding fastening portion with the flange portion 2 from the outer peripheral direction.

The second winding roll 7 in the present invention
As shown in FIG. 4, since the roll groove 71 is characterized in particular, and the receiving portion 72 extending in the lateral direction is provided below the roll groove 71, a recess for preventing the cover hook CH from escaping is formed. 73 is formed.

Therefore, when the second winding roll 7 according to the present invention is wound using the conventional second winding roll 7 having no lateral receiving portion under the roll groove 71 as shown in FIG. The structure is such as to effectively prevent the decrease of the overlap OL due to the return of the cover hook CH to the lower side, which has been a problem.

The receiving portion 72 of the second winding roll 7
Depth: d _{2 If the} roll is tightened with a roll having a value that is not more than twice the thickness of the metal lid and less than the total thickness of the flange portion of the plastic container, the winding part will be sufficiently compressed during the second winding. Therefore, no void is generated inside the tightening portion, and a good inner shape of the tightening can be obtained.

The degree of bending of the cover hook CH in the course of winding and the final winding width of the winding portion 3: W is the groove height of the first winding roll 6, h ₁ , and the second winding. The groove height of the roll 7 is defined by h ₂ . Therefore, the degree of bending of the cover hook CH and the winding width can be freely set by changing the groove heights h ₁ and h ₂ of the roll.

As a result of various studies on the plastic container with the metal lid double-fastened by using the first and second winding rolls as described above, the groove height: h ₁ of the first winding roll 6 was determined. 2.25 to 2.65 mm, and the groove height: h ₂ of the second winding roll 7 is 2.40 to ₂ .
By setting the groove height of the first winding roll 6 to be 80 mm and the groove height h ₁ of the second winding roll 7 to be smaller than the groove height h ₂ of the second winding roll 7, the closed plastic container with the metal lid is closed. Tightening thickness: T is 1.95 to 2.05 mm,
Winding width: W can be easily accommodated in the range of 2.40 to 2.80 mm.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, the following plastic container 1, metal lid 5,
The first winding tightening roll 6 and the second winding tightening roll 7 were used.

The plastic container 1 is made of a laminated material containing an oxygen barrier resin, and the flange portion 4 has a thickness TF of 0.50 mm and a width WF of 2.30 m.
m, and the inner diameter of the opening was 74.0 mm. Further, as the metal lid 5, an aluminum one having a thickness of 0.28 mm and having the peripheral edge portion 4 curled in advance was used. And (roll groove height of the first winding roll 6: h ₁ ) <
(Roll Groove height of the second winding clamping roll 7: h ₂₎ and made way performs double seamed to give the plastic container with a metal lid.

The depth d ₂ of the receiving portion 72 of the lower part of the second winding roll 7 was 1.00 mm.
With respect to the plastic container with the metal lid thus obtained, the quality of winding performance was evaluated by the following method.

Roll groove height of the first winding roll 6: h ₁
2.05, 2.25, 2.45, 2.65, 2.85
Table 1 shows whether or not the sealing property is good in the case of mm, and the roll groove height: h ₂ of the second winding roll 7 is 2.20, 2.40, ₂ .
Table 2 shows whether or not the sealability was good when the ones having the thicknesses of 60, 2.80 and 3.00 mm were used. The winding width: W corresponds to the roll groove height of the second winding roll 7: h ₂ .

The winding tightening thickness thus obtained: T is 1.9
Table 3 shows the sealability of plastic containers with a metal lid of 0, 1.95, 2.00, 2.05, 2.10 mm.
, Respectively.

1) Evaluation of hermeticity: A container container 11 was filled with an aqueous starch solution, and a plastic container with a metal lid was wound, so that bacteria could invade the container container 11 if there was a leak point inside the container. Treated in the heat sterilizer prepared in 1., and then left in a constant temperature bath at 35 ° C. for 2 weeks, tested for bacteria in the container housing 11 to determine whether it is negative or positive, as well as putrefaction gas of the plastic container 1, etc. The presence / absence of swelling was visually determined.

2) Evaluation of appearance of winding: Visual inspection of the winding portion of the obtained plastic container with a metal lid is performed.
Those without any abnormality were evaluated as (◯), those with irregularities recognized (Δ), and those in which the tip of the container flange portion 2 or the tip of the cover hook CH of the metal lid was slightly visible were judged as (x).

3) Internal evaluation of winding: The obtained plastic container with a metal lid is axially cut, and an enlarged photograph of the cross section is photographed by a real-life microscope. There is almost no void and the overlap OL is 1.0 mm or more. Is (○), if there are few gaps and the overlap OL is between 0.5 mm and 1.0 mm (△), if there are gaps or the overlap OL is 0.5 mm or less, it is judged as (x). did.

[0031]

[Table 1]

[Table 2]

[Table 3] As shown in Tables 1 and 2, the groove height of the first winding roll 6:
h ₁ is 2.25 to 2.65 mm, groove height of the second winding roll 7: h _2, that is, winding width: W is 2.40 to 2.8.
It has been found that in the range of 0 mm, a good winding state can be obtained without any problem in the winding appearance, the inside of the winding, and the sealing property.

Further, h ₁ is 2.85 mm, h ₂ or W
When the width is increased to 3.00 mm, the cover hook CH is returned, while h ₁ is 2.05 mm and h ₂ · W is 2.20.
If the width is less than the above range, problems such as cutting the container flange portion 2 at the tip of the cover hook CH may occur, and in any case, a good winding internal shape could not be obtained.

As shown in Table 3, the winding thickness of the plastic container with the metal lid wound by the roll: T
It was found that when the value is 1.95 to 2.05 mm, a good winding state can be obtained without any problems in the winding appearance, the inside of the winding, and the sealing property.

Further, the winding thickness of the winding container with a metal lid: When T is increased to 2.10 mm, a void occurs inside the winding. It was also found that a problem such as internal deformation occurred and a good winding internal shape could not be obtained.

Further, the groove bottom of the receiving portion the depth of the second volume tightening roll 7: d ₂ twice and the plastic container flange becomes more than the sum of the second thickness TF second volume tighten the thickness TC of the metal lid 5 It was found that sometimes the tightening portion could not be compressed sufficiently and voids were generated inside the tightening, so that a good inner shape of the tightening could not be obtained.

[0036]

As described above, according to the present invention, the plastic container having the flange portion for winding the metal lid in the opening portion of the container and the peripheral portion for forming the winding portion between the flange portion and the plastic container are provided. When the metal lid is double-tightened from the outer peripheral direction, the tightening thickness T is 1.95 to 2.05 m.
m, and winding width: W is a plastic container with a metal lid having a range of 2.40 to 2.80 mm, so the groove height of the first winding roll 6 and the second winding roll 7: Simply defining the h ₁ and h ₂ and providing a receiving portion 72 extending laterally below the roll groove 71,
A special plastic container as proposed previously,
It is possible to obtain a plastic container with a metal lid in a double winding state having a good and sufficient sealing property equivalent to a metal can without using a winding machine.

[Brief description of drawings]

FIG. 1 is a front sectional view showing an example of a plastic container with a metal lid of the present invention.

FIG. 2 is a front sectional view showing an example of a metal lid according to the present invention.

FIG. 3 is a front sectional view of a first winding roll for double-winding a plastic container with a metal lid according to the present invention and a winding state.

FIG. 4 is a front sectional view showing a second winding roll and a winding state.

FIG. 5 is a front cross-sectional view of a conventional double winding portion and a conventional second winding roll.

[Explanation of symbols]

 1 plastic container body 2 flange part 3 winding part 4 peripheral part 5 metal lid T winding thickness W winding width

Claims (1)

[Claims] 1. A plastic container having a flange portion for winding a metal lid at an opening of the container, and a metal lid having a peripheral portion for forming a winding portion between the flange portion and a metal lid in a circumferential direction. Tightening thickness when double winding: T
Is 1.95 to 2.05 mm, and the tightening width: W is 2.
A plastic container with a metal lid, such as in the range of 40-2.80 mm.