JP6604123B2 - Sealed container - Google Patents

Description

  The present invention relates to a sealed container formed by joining a resin container and a resin molding lid, and more specifically, it is effectively prevented that a joint portion having an easy-opening property is peeled off except for an opening operation. Related to sealed containers.

In a sealed container formed by joining a resin lid to a resin container, an easily opened sealed container that can be opened manually is widely used.
As such an easy-open sealed container, it is generally widely performed that a flexible film-like lid is sealed by heat sealing in a cup-shaped container having a flange portion (Patent Document 1, etc.).
However, since a flexible film-like lid is inferior in piercing strength, a sealed container in which such a flexible film-like lid is heat-sealed to the flange portion of the container is often used as an outer case. They are stored or distributed with overcaps and the like. Another problem is that the flexible film-like lid cannot be resealed.

In order to solve such a problem of a flexible film-like lid, a rigid molding lid is also widely used. In Patent Document 2 below, a molding lid having easy-openability and resealability is applied. A sealed container has been proposed.
In general, since the molding lid has high rigidity, a large force is required for opening compared with the flexible film-like lid described above. Therefore, the opening tab that serves as a clue for the opening is used for the container and the molding lid. It is integrally formed in a shape that protrudes greatly outward from the container flange portion to be a joint location.

JP-A-8-268472 Japanese Patent No. 4733452

However, the unsealing tab that protrudes more outward than the container flange is highly likely to have some external force during transportation, display, etc., and this biased external force is partially due to the rigidity of the molding lid. However, there is a problem that even if there is no intention to open the joint, it is opened.
Accordingly, an object of the present invention is to effectively prevent the unsealing of the container from being unintentionally opened even in the case of using a rigidly formed lid having an opening tab integrally formed in a sealed container having easy-openability. Is to provide a sealed container.
Another object of the present invention is to provide a sealed container that can be sealed by laser welding and is excellent in productivity, and is excellent in both sealing performance and opening performance.

According to the present invention, in a sealed container formed by joining a resin container having a container flange portion formed of a bottom portion and a side wall portion and extending outward from an upper end of the side wall portion, and a resin lid, The resin lid is a resin-molded lid having an opening tab that protrudes outward from the outer peripheral edge of the container flange portion, and the opening tab includes a vicinity of the outer peripheral edge of the container flange portion and an outer peripheral edge of the container flange portion. A step is formed at a position corresponding to the outside, and the step is a step that positions the opening tab below the upper surface of the resin-molded lid, and the opening tab with the step as a reference line A sealed container is provided that is foldable downward.

In the sealed container of the present invention,
1 . Before Symbol step, that the perforations are formed,
2 . The resin-molded lid has a bottom lid shape and a side wall portion, and a drop lid shape having a lid flange portion extending outward from the upper end of the side wall portion;
3 . Bonding of the resin molded lid and the container flange portion is a welded state having an easy-opening property with an adhesive strength of 25 N or less and a sealing performance with a burst strength of 20 kPa or more,
4 . The joining of the resin container and the resin molding lid is laser welding,
5 . The outer diameter of the portion excluding the opening tab of the resin molded lid is not more than the outer diameter of the container flange portion,
Is preferred.

In the sealed container of the present invention, the opening tab that protrudes outward from the outer peripheral edge of the container flange portion is integrated through a step at a position corresponding to the vicinity of the outer peripheral edge of the container flange portion and the outer side of the outer peripheral edge of the container flange portion. Therefore, the opening tab can be bent downward with this step as a reference line. Therefore, the opening tab can be folded to the side surface of the container at the time of conveyance or display, and it is possible to effectively prevent an unintended external force from acting on the opening tab. In addition, even when an external force is applied to the folded opening tab, the force in the direction of peeling the joint, that is, the upward force is hardly applied to the joint surface, and the sealing performance can be maintained. It is.
Moreover, the resin container and the resin molding lid are joined so that the adhesive strength is 25 N or less (measurement method: JIS S 0022) and the burst strength described later is 20 kPa or more (measurement method: JIS Z 0238, conforming to the Food Sanitation Law). By setting it as the state which carried out, it has comprised the easy-opening performance and sealing performance which are the performances which conflict, in good balance.

Moreover, since the resin molding lid used for this invention can form a level | step difference simultaneously when shape | molding from a resin-made sheet | seat, shaping | molding is also easy.
Further, in the sealed container of the present invention, since the resin container and the resin molding lid are joined by laser welding, the resin container can be welded at high speed and the productivity is excellent. Moreover, by using a resin lid having a drop lid shape, it can be attached to the container at the time of welding, so that laser welding can be performed efficiently.
Furthermore, by making the outer diameter of the part excluding the opening tab of the resin molded lid smaller than the outer diameter of the container flange, it is possible to prevent external force from acting directly on the resin molded lid. It is possible to reliably prevent the action of an external force on the joint portion.

It is the perspective view which looked at an example of the sealed container of this invention from diagonally upward. It is the perspective view which looked at an example of the resin-made lid | cover used for the sealed container of this invention from diagonally downward. It is the perspective view which looked at another example of the sealed container of this invention from diagonally upward. It is a partial side view which shows another example of a level | step difference.

(Sealed container)
As shown in FIG. 1 (A) as an example, the sealed container of the present invention is composed of a resin container indicated by 1 as a whole and a resin-made lid indicated by 10 as a whole, which have easy-openability. Are joined and sealed.
The resin container 1 generally includes a bottom portion 2 and a side wall portion 3, and a container flange portion 4 extending outward from the upper end of the side wall portion 3 is formed. In the embodiment shown in FIG. 1, in addition to the above basic configuration, a container fitting portion 5 that is in close contact with the lid fitting portion 12 a-3 of the resin molding lid 10 shown in FIG. A container step 6 serving as a stack portion is formed below the fitting portion 5.
On the other hand, the resin-molded lid 10 shown in FIGS. 1 and 2 schematically includes an outer side wall portion 12a that hangs down from the inner peripheral edge of the lid flange portion 13 and an annular bottom portion 12c that continues to the lower end of the outer side wall portion 12a. The opening side tab 12 is formed integrally with a part of the lid flange portion 13 through a step 15. In the lid flange portion 13, the resin container 1 and the resin molding lid 10 are joined so as to have easy-opening performance and sealing performance. In this embodiment, the step 15 of the resin molding lid 10 is formed such that the opening tab 14 is positioned below the upper surface of the lid flange portion 13.
In the embodiment shown in FIGS. 1 and 2, in addition to the above basic configuration, the upper portion of the outer side wall portion 12 a of the resin molding lid 10 is a lid fitting portion 12 a-3 that is in close contact with the container fitting portion 5 described above. It is comprised, and the lower part of the lid fitting part 12a-3 is comprised as the introduction part 12a-1 for introduce | transducing into the resin-made containers 1 smoothly, Between the lid fitting part 12a-3 and the introduction part 12a-1 Is configured as an outer side wall step 12a-2 extending horizontally and inwardly. The lid fitting portion 12a-3 has a taper shape that spreads outward so as to increase the inner diameter as it goes downward, and the introduction portion 12a-1 has a taper shape whose inner diameter decreases as it goes downward.

As described above, in the sealed container of the present invention, as shown in FIG. 1B, the opening tab 14 can be bent downward with the step 15 as a reference line. Since the step 15 of the resin-made lid 10 is formed outside and in the vicinity of the outer peripheral edge of the container flange portion 4, when the opening tab 14 is bent downward, the force generated by the bending is increased by the outside of the lid flange portion 13. It acts downward on the periphery and hardly acts on the joint.
In addition, the folded opening tab 14 is less likely to receive an unintended impact during transportation or the like as compared with the case where the opening tab 14 extends in the horizontal direction. As described above, the external force that moves in the lateral direction has little influence on the joint, and there is no risk of impairing the sealing performance.
Further, in the sealed container shown in FIG. 1, the outer diameter of the lid flange portion 13 excluding the position where the opening tab 14 of the resin molded lid 10 is formed is equal to or smaller than the outer diameter of the container flange portion 4 of the container 1. Therefore, a biased impact is not applied to the lid flange portion 13, and it is effectively prevented from affecting the joint portion.

[Resin molding lid]
The resin-molded lid applied to the sealed container of the present invention can adopt a conventionally-known resin-molded lid except that the opening tab is formed through the steps described above. A resin molding lid formed by thermoforming can be suitably used.
The shape of the resin molding lid 10 is not limited to the drop lid shape shown in FIGS. 1 and 2, and the outer outer wall portion 12 a in FIGS. 1 and 2 is a straight shape extending downward from the lid flange portion 13. It is also possible to form a drop lid with a bottom surface extending horizontally and inwardly from the lower end of the outer outer wall portion 12a.
Further, it may have a flat plate shape without the outer side wall portion 12a, the inner side wall portion 12b, and the annular bottom portion 12c in FIGS. However, as described above, a drop lid shape is desirable because the resin molding lid 10 can be stably attached to the resin container 1 at the time of joining. Moreover, it is suitable because it can be resealed after opening by having a drop lid shape that can be fitted to the container mouth.

FIGS. 3A to 3C are views showing another example of a resin molded lid used in the sealed container of the present invention.
The resin-molded lid 10 shown in FIG. 3A has an opening tab 14 formed through a recess 17 that forms a step with the lid flange portion 13. As shown in FIG. 4A for explaining the cross section of the stepped portion, the concave portion 17 has a bottom surface 17c between a side surface 17a on the container side and a side surface 17b on the opening tab side. The bottom surface 17 c is located on the outer side and in the vicinity of the outer peripheral edge 4 a of the flange portion 4, and forms a step with the upper surface of the molding lid 10.
In this embodiment, the opening tab 14 can be easily folded due to the presence of the recess 17 and can be bent in the same manner as shown in FIG. 1B with the recess 17 as a reference line.

As shown in FIG. 1, the step in the resin molding lid used in the present invention may form a step with the opening tab positioned below the lid flange portion of the resin molding lid, As shown in FIGS. 3A and 4A, a minute flat surface (bottom surface 17c) is formed between the upper surface of the molding lid and the opening tab, which is located below the upper surface of the lid flange portion and the opening tab. It is good also as a level | step difference by the made recessed part.
In addition to forming a single recess as shown in FIG. 3A, two rows of linear recesses can be formed in parallel as shown in FIGS. 3B and 4B.
Further, as shown in FIG. 3 (C), a linear perforation 18 is formed on the opening tab 14 (step 15) of the resin molding lid shown in FIG. 1 and FIG. Bending can be made easier.

  In the present invention, the level difference formed on the resin molding lid is not limited to this, but it is preferable to form a level difference of about 2 to 4 times the thickness of the resin sheet constituting the resin molding lid. If the level difference is smaller than the above range, the opening tab may be more difficult to bend than when it is within the above range. On the other hand, if the level difference is larger than the above range, the opening tab may be opened when opening. It may be difficult to pull up the tab.

Moreover, when forming a level | step difference with a recessed part, although the width | variety of the bottom part of a recessed part is not limited to this, It is preferable to exist in the range of 1-3 mm. If the width of the bottom surface of the recess is narrower than the above range, the flexibility imparted by the formation of the step becomes insufficient, and there is a risk of breaking when the opening tab is bent, while the recess is more than the above range. If the width of the bottom surface is wide, the opening tab becomes too large, which is inferior to that in the above range in terms of economy, and the opening property may be impaired.
Furthermore, the position of the step is larger than and near the outer peripheral edge of the container flange portion. Specifically, as shown in FIG. 4A, the distance L1 from the outer peripheral edge 4a of the container flange portion is 0. It is desirable that it is in the range of 2 mm or less. If the level difference coincides with the outer periphery of the container flange, the resin-molded lid may be damaged with the outer periphery of the container flange serving as a fulcrum (reference line) when the opening tab is bent. If it is too far away, an external force may act on the joint when the opening tab is folded.

Moreover, when forming a perforation in a level | step difference, it can form by the press work etc. which used the perforation blade. The lengths of the perforated slit portion and the non-slit portion are not limited to this, but are preferably formed alternately at intervals of 2 to 3 mm in length. If the length of the slit portion and the non-slit portion is shorter than the above range, the opening tab may be easily cut when the opening tab is bent. On the other hand, if the length is longer than the above range, the opening tab is narrow. Then, there exists a possibility that a slit may enter only in one side of the tab for opening.
Further, the position of the perforation 18 is preferably in the vicinity of the step, but specifically, as shown in FIG. 4C, the distance L2 from the step is preferably in the range of greater than 0 mm and less than or equal to 5 mm. When the perforation is inside the step (on the lid flange), when the opening tab is folded, the step is also bent starting from the perforation, the step hits the outer periphery of the container flange, and is made of resin. There is a possibility that the molding lid may peel off. On the other hand, if the perforation is too far from the above range, the effect of bending the opening tab may be lost.
The perforation can also be applied to the case where the steps in FIGS. 3A and 3B are formed by recesses. The position of the perforation is when the recess is a single line as shown in FIG. 3 (A), and the bottom surface 17c (see FIG. 4 (A)) and when the recesses are arranged in two rows in parallel as shown in FIG. 3 (B). Is preferably formed on the bottom surface 17C1 (see FIG. 4B) on the inner side (resin container side).

In the resin molded lid used for the sealed container of the present invention, it is preferable that the outer diameter of the lid flange portion excluding the opening tab is equal to or smaller than the outer diameter of the container flange portion. As a result, as described above, it is possible to prevent an impact from directly acting on the resin molding lid, and it is possible to effectively prevent the joint portion having easy-opening properties from peeling off and being opened unintentionally.
The resin-made lid can be molded from a known thermoplastic resin conventionally used for packaging containers, but is not limited thereto, but is not limited to olefinic resins such as polyethylene and polypropylene, and polyesters such as polyethylene terephthalate and polybutylene terephthalate. Resins and the like can be preferably used, and when joining by laser welding or heat seal welding, as long as it is made of the same kind of resin as the resin container used on at least the welding surface, either a single layer structure or a multilayer structure There may be.

[Resin container]
As long as the resin container used for the sealed container of the present invention can be joined to the above-mentioned resin-molded lid, a conventionally known flanged container can be used. The molding method such as extrusion molding, injection molding, compression molding and direct blow molding is not limited.
Preferably, it is preferably produced by a conventionally known thermoforming method, such as pressure forming, vacuum forming, or vacuum / pressure forming combining vacuum forming and pressure forming, using or after using a plug, and / or It is preferable to perform molding by plug-assist molding or the like for pressure forming.
The resin container is preferably made of the same thermoplastic resin as the resin molding lid described above. When laser welding is performed from the container side as described later, the flange portion needs to have transparency. However, similar to the resin molding lid, either a single layer structure or a multilayer structure may be used.

(Sealing method)
In the sealed container of the present invention, it is important that two contradictory performances of easy opening and sealing performance are secured, and the easy opening performance is an adhesive strength of 25 N or less (measurement method: JIS S 0022). As a sealing performance, the burst strength (measuring method: JIS Z 0238, conforming to the Food Sanitation Law) needs to be 20 kPa or more, and the sealed container of the present invention can satisfy both of these values. It is desirable to be sealed. Specifically, it is preferable that the adhesive strength is in the range of 15 to 25 N and the burst strength is in the range of 20 to 50 kPa. As for sealing performance, the maximum pressure at the time of bursting of the internal pressure strength test shown in the Ministry of Health and Welfare Notification No. 370 dated December 28, 1959 based on the Food Sanitation Law must satisfy the rule that it is 20 kPa or more, In the packaging container industry, this maximum pressure is referred to as burst strength.
As a joining method of the resin container and the resin molding lid, various conventionally known joining methods such as welding by heat sealing, welding by laser irradiation, or adhesion by an adhesive can be adopted. In the present invention, the resin lid is used. Since it is a molding lid, welding by laser irradiation is particularly suitable. That is, since the molded lid is generally made of a resin sheet having a thickness of 0.3 mm or more, heat conduction takes time in welding by heat sealing, but in laser welding, there is no restriction on the wall thickness of the container and lid, High-speed sealing is possible, and productivity is excellent.

[Laser welding]
In the sealed container of the present invention, when joining the resin container and the resin molding lid by laser welding, since laser welding is stronger than heat seal, in order to ensure easy opening, On the welding surface of the container and the container lid, it is necessary to use a resin that can exhibit easy-openability and to set the seal width in a desired range.
Also, as general laser welding conditions, it is made of a resin that can transmit laser light at the bonding interface between the resin container and the resin molding lid, and contains a laser absorber that can absorb the laser light and generate heat. is required.
The combination of the resin container and the resin molding lid that can easily be opened by laser irradiation is not limited to this, but the following combinations can be suitably used. That is, the resin container is made of polypropylene capable of transmitting laser light, and the resin molding lid is a base material layer made of polypropylene, and a blend containing polypropylene, propylene-ethylene random copolymer and low density polyethylene containing a laser absorber. A combination comprising at least two layers of a laser absorption layer made of a material and arranged so that the laser absorption layer is located on the interface side of the resin container and the resin molding lid can be suitably used.
A conventionally well-known thing can be used for a laser absorber, and can mention carbon black, metal powders, such as iron powder and aluminum powder, edible bamboo charcoal, or a pigment, However, Carbon black can be used suitably especially. it can.

Further, in order to satisfy the easy opening property and the sealing performance, that is, the aforementioned adhesive strength of 25 N or less and the burst strength of 20 kPa or more, it is necessary to use a combination of the above-described resin container and resin molding lid capable of expressing the easy opening property. Although important, it is desirable to adjust the welding conditions described later as appropriate.
As a laser beam used for welding, a gas laser, a solid-state laser, or a semiconductor laser can be used, and a semiconductor laser can be particularly preferably used. The output of the laser oscillator is preferably in the range of 200 to 500 W, and the wavelength of the laser beam is preferably in the range of 200 nm to 20 μm. The focal length is preferably in the range of 10 to 200 mm, and the sweep speed is preferably in the range of 400 to 1100 mm / sec.
In particular, the spot diameter (seal width) of the laser beam depends on the resin used for the welding surface of the resin container and the resin molding lid, but is directly related to the seal strength and affects the opening performance and sealing performance. It is preferable that it exists in the range of 1-3 mm, especially 1.5-2.0 mm. If the seal width is narrower than the above range, the sealing performance may be inferior. On the other hand, if the seal width is wider than the above range, easy-openability may not be obtained.

When laser irradiation is a combination of the resin container and the resin molding lid of the resin of the specific example described above, while rotating the resin container on which the resin molding lid containing the laser absorber is placed, Laser irradiation is performed on the flange portion from the container side. Of course, the resin that makes up the resin container and the resin molding lid can be changed and laser irradiation can be performed from the resin molding lid side, but a laser absorption layer is formed on the resin molding lid from the viewpoint of productivity and economy. It is desirable that
In this embodiment, it is preferable that the thickness of the container flange portion that transmits the laser beam is in the range of 0.5 to 2.0 mm. If the thickness is less than the above range, reliable welding may not be performed. On the other hand, if the thickness is greater than the above range, the laser beam may reach the laser absorption layer under normal conditions. There is a possibility that it may become difficult, and there is a possibility that reliable welding cannot be performed.
The blending amount of the laser absorber in the laser absorption layer varies depending on the flange portion of the resin molding lid, the thickness of the laser absorption layer, the laser welding conditions, etc., and cannot be specified in general, but carbon black was used as the laser absorber. In the case, it is preferably contained in the laser absorbing layer in an amount of 500 to 3000 ppm.

[Heat seal welding]
In the sealed container of the present invention, the resin container and the resin molding lid can be joined by heat seal welding, and in this case, it can be performed under conventionally known heat seal conditions, as described above. Since the resin molding lid has a thickness, it is preferable to appropriately adjust the heat sealing time and the heat sealing temperature.
In the case of welding by heat sealing, the resin container and the resin molding lid are preferably made of the same kind of resin having at least a joining surface having heat sealing properties, but are not limited thereto, but are olefins such as polyethylene and polypropylene. Resins or polyesters such as polyethylene terephthalate can be exemplified.
Moreover, it can also be set as the laminated body using gas barrier materials, such as aluminum foil and an ethylene vinyl alcohol copolymer, as an intermediate | middle layer.

[Others]
In the sealed container of the present invention, as long as desired easy opening performance and sealing performance are expressed, the joining method of the resin container and the resin molding lid is not limited to laser welding and heat seal welding, for example, adhesive resin May be bonded by applying to the bonding interface between the resin container and the resin molding lid, or may be welding by spin weld or ultrasonic wave.
The adhesive resin varies depending on the material of the resin container and resin molding lid to be used, and cannot be generally defined, but conventionally known adhesive resins such as hot melt adhesives and epoxy adhesives can be used. .

  DESCRIPTION OF SYMBOLS 1 Resin container, 2 Bottom part, 3 Side wall part, 4 Container flange part, 10 Resin molding lid, 12a Outer side wall part, 12b Inner side wall part, 12c Annular bottom part, 13 Cover flange part, 14 Opening tab, 15 steps, 16 top surface, 17 recesses (steps), 18 perforations.

Claims (6)

In a sealed container formed by joining a resin container formed of a container flange part formed of a bottom part and a side wall part and extending outward from the upper end of the side wall part, and a resin lid,
The resin lid is a resin-molded lid having an opening tab that protrudes outward from the outer peripheral edge of the container flange portion, and the opening tab includes the vicinity of the outer peripheral edge of the container flange portion and the outside of the container flange portion. A step is formed at a position corresponding to the outer side of the periphery, and the step is a step that positions the opening tab below the top surface of the resin molding lid, and the step is used for opening with the step as a reference line. A sealed container characterized in that the tab can be bent downward. In the step, sealed container according to claim 1, wherein the perforation is formed. The sealed container according to claim 1 or 2, wherein the resin-molded lid has a drop lid shape having a bottom surface and a side wall portion, and a lid flange portion extending outward from the upper end of the side wall portion. The sealed container according to any one of claims 1 to 3 , wherein the resin-molded lid and the container flange portion are in a welded state having an easy-open property with an adhesive strength of 25 N or less and a sealing performance with a burst strength of 20 kPa or more. Sealed container according to claim 1-4 junction of the resin vessel and the resin formed cap is laser welded. The sealed container according to any one of claims 1 to 5 , wherein an outer diameter of a portion excluding the opening tab of the resin molded lid is equal to or smaller than an outer diameter of the container flange portion.