JPH0199980A - Easily openable package container and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture package containers excellent in sealability and openability at low cost without need of complicated steps, by forming peelably the innermost layer of a multilayer cap and a layer contacting this layer, and by forming recessed by pressing in the cap innermost layers inside and outside the sealing part. CONSTITUTION:A container body 3 is filled with the content and capped with a multilayer cap, and the cap is heat-sealed tight with the innermost layer of the container body at the flange 4. Recesses 6, 7 are formed in the inside end and outside end of the cap innermost layer of a heat sealing part 5. The recesses 6, 7 are formed by heat sealing by pressing the multilayer cap to the flange 4 with a seal ring 9. Before opening, the recess 7 of the outside end of heat sealing part starts to peel the innermost layer of the multilayer cap from a layer contacting it: a layer 1 of the multilayer cap is peeled from the innermost layer 2 over a range from recess 7 to recess 6. The recess 6 of the inside end of heat sealing part stops the peeling of the multilayer cap: after its peeling up to here, one inside the heat sealing part is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an easy-to-open packaging container and a method for manufacturing the same. More specifically, the present invention is suitable for packaging foods, beverages, etc., particularly for heat sterilization packaging, and is capable of being strongly heat-sealed and has excellent sealing properties.
The present invention relates to an easy-to-open packaging container that has excellent unsealability and a method for manufacturing the same.

[Conventional technology]

BACKGROUND ART Conventionally, for packaging foods and the like, containers are filled with contents and then sealed by heat-sealing a lid. However, when heat-sealing packaging containers formed in this manner have high heat-sealing strength to improve sealing performance, they are difficult to open when the contents are used, making it necessary to open them with a knife, etc. If you select a material with appropriate heat-sealing strength to improve unsealability, the sealing properties will vary greatly depending on heat-sealing conditions such as temperature, pressure, and time, as well as contaminants such as fillers, making it difficult to obtain a certain adhesive strength. Since the sealing performance deteriorates, there is a problem in that it cannot be used particularly in packaging where the internal pressure is high, such as in retorts, etc., which are subjected to heat sterilization.

In order to solve this problem, Japanese Patent Application Laid-Open No. 61-190461
The publication describes a method of selecting a resin with appropriate internal cohesive strength as the sealing layer resin and achieving easy opening by utilizing cohesive failure of the sealing layer resin, but the sealing layer resin is limited. There is also the problem that the peeling surface is messy.

Furthermore, in JP-A-61-193848, a combination of a multilayer material consisting of an ethylene-vinyl acetate copolymer and an ionomer and a resin material consisting of an ionomer is selected as the resin material, heat-sealed, and the seal is easy to open. However, since the seal must be torn and opened, the combination of resin materials is limited to the above, and the opening side and the remaining side cannot be cut cleanly due to tearing and opening. There is a problem that it is aesthetically inferior.

Furthermore, Japanese Patent Application Laid-Open No. 54-143388 discloses that at least one of the resin materials to be heat-sealed is provided with a resin printed layer that is easy to break.
Publication No. 03372 describes a method of providing a releasable printed layer on at least one of the resin materials to be heat-sealed to facilitate peeling of the resin material and achieve easy opening, but both methods require a printing process. In addition, the process is complicated because it is necessary to match the printed part and the seal part, and - fishing by boat is not possible.

[Problem that the invention seeks to solve]

As shown in FIGS. 6 and 7, the present inventors previously heat-sealed a multilayer lid material with cuts 6' and 7' provided in the innermost layer 2 of the multilayer lid material to the flange portion 4 of the container body. We have proposed an easy-to-open container with excellent sealability and ease of opening. However, manufacturing this container requires a step of forming incisions in the lid material, and since the lid material is thin, it is not easy to form these incisions. Further, there were manufacturing problems such as difficulty in aligning the notch of the lid material and the sealing portion during heat sealing.

The present invention makes it possible to obtain an easy-to-open packaging container with excellent sealing performance and excellent unsealability using a normal sealing method by utilizing the glabellar peeling of a heat-sealed multilayer lid material, and It is an object of the present invention to provide an easy-to-open packaging container and a method for manufacturing the same, which can manufacture the easy-to-open container at low cost without requiring complicated processes.

[Means for solving problems]

That is, the present invention provides a packaging container in which a multilayer lid is heat-sealed to a container flange, in which the innermost layer of the multilayer lid and the layer in contact therewith are formed so as to be releasable, and the inner and outer lids of the sealed portion are separated. The present invention relates to an easy-to-open packaging container characterized in that a concave portion is formed in the innermost layer of the material by pressing. Such an easy-to-open packaging container has, for example, an innermost layer and a layer in contact with the innermost layer formed on the container flange so as to be peelable, and the innermost layer is made of a material with a lower melting point or softening point than the material of the layer in contact with the innermost layer. The multilayer lid material is a thermoplastic resin layer.
It can be manufactured by heat sealing using a seal ring having convex portions on the inner and outer peripheral edges.

Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is an explanatory cross-sectional view illustrating a preferred embodiment of the easy-to-open packaging container of the present invention and its manufacturing method.

In FIG. 1, 2 is the innermost layer of the multilayer lid material, and l is the layer in contact with this. 3 is a container body; 4 is a flange portion of the container; after the container is filled with contents, it is covered with a multilayer lid material, and this lid material is tightly heat-sealed between the innermost layer of the container body and the flange portion 4; 5 indicates the position of the heat seal portion. Concave portions 6.7 are formed at the inner and outer ends of the innermost layer of the lid material of the heat-sealed portion. Reference numeral 9 denotes a seal ring, which is used to press and heat-seal the multilayer lid material to the container flange to form a concave portion. The concave part 7 at the outer end of the heat seal part is for starting peeling between the innermost layer of the multilayer lid material and the layer in contact with it when the package is opened.
By lifting up, the layer 1 and the innermost layer 2 of the multilayer lid material from the recessed part 7 to the recessed part 6 are peeled off. The concave part 6 at the inner end of the heat-sealed part is for stopping the peeling of the multi-layer lid material, and after the multi-layer lid material has been peeled off to this point, the peeling of the lid material stops and the multi-layer lid material inside the heat-sealed part is opened. will be held.

The shape of the recessed portion is preferably such that the tip of the recessed portion reaches the flange surface of the container body from the viewpoint of ease of opening. Further, this concave portion may be provided in an annular shape such as a circle, a triangle, or a quadrangle along the entire inner periphery of the flange, or a portion may be left. If the lid is to be removed with a portion of the lid still attached, avoid creating a recessed portion in that portion.

As shown in FIG. 1, the seal ring for forming the concave portion has convex portions 10.11 on the inner and outer peripheral edges of the ring that protrude from the heat-sealing surface. Then, there is a width t between the inner convex part and the heat seal part.
A material having a non-pressing portion 12 is preferably used. When the multilayer lid material is heat-sealed to the container flange using such a seal ring, a non-heat-sealed portion having a width t is formed between the inner concave portion and the inner end of the heat-sealed portion. In this way, when the multilayer lid material is separated by one dragon from the inside,
Stress is concentrated at point A in the figure, and as a result, peeling from the concave portion 6 is less likely to occur, so the peel strength from the inside is greater than the peel strength from the outside, resulting in high pressure resistance and good sealing performance. The width of t is usually 1 to 10 mm, preferably 2
~10m.

The width of the seal ring is not particularly uniform, and is usually 1 to 10W.
m, and the height h of the convex portion on which the ring peripheral portion is provided is not particularly limited, and may be determined in consideration of the material of the lid material, etc., and is usually 10 to 500 m. un, preferably 20-300 μm
It is.

2 and 3 are partial cross-sectional explanatory views showing other aspects of the easy-to-open container of the present invention and the manufacturing method thereof, and in FIG. 2, the container is provided with ribs.

In FIG. 3, the container is provided with a curl, and the seal ring is not provided with a non-pressing portion. FIG. 4 is a sectional view showing the state of the container shown in FIG. 3 after being opened.

The easy-open container of the present invention can be easily opened even if the container has such curls and lips.

The shape of the multilayer container main body in the easy-to-open packaging container of the present invention is not particularly limited, but is usually circular, square, etc., and the lid material is heat-sealed in an annular shape along the flange portion of this shape. .

The multilayer lid material used in the present invention consists of a base material layer and an innermost layer that is sealed to the container body, and the innermost layer is made of a thermoplastic resin that has a lower melting point or softening point than the material of the base material layer that is in contact with it. It has become. The base material layer may be a single-layer film of plastic such as polypropylene, inorganic-filled tyrene-vinyl alcohol copolymer, polyvinylidene chloride resin, or polyamide resin, or a multilayer film of these plastics, paper, aluminum foil, iron, or any of these. Examples include composite materials. As the thermoplastic resin for the innermost layer, polyethylene' such as low density polyethylene and high density polyethylene; polypropylene; density 0.86 to 0.9;
Ethylene-α-olefin copolymer of No. 5; ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-
Ethylenically unsaturated carboxylic acid copolymers such as maleic anhydride copolymers, metal salts such as zinc, sodium, and calcium salts of ethylene-acrylic acid copolymers (ionomer resins); Examples include resins that have heat sealability.

There are no particular restrictions on the multilayer lid material as long as the interlayer adhesive strength is lower than the heat seal strength between the container body and the multilayer lid material, and the layers of the multilayer lid material are formed so that they can be peeled off when the lid material is opened. The glabella peel strength of this multilayer lid material is usually 200 to 15
00 g/15 m (pulling speed 300 wn/min, the same applies hereinafter), preferably about 300 to 1200 g/15 m. The thickness of the innermost layer of multilayer lid material is usually 10 to 100μ.
m, preferably 15 to 70 μm.

Although the multilayer lid material may remain in the form of a film, it can be shaped into a drop lid as shown in FIG.

The shape of the recess of the drop lid is not particularly limited as long as it can fit with the opening of the container body and expel air, and may be curved,
It may have a shape with a flat bottom surface. In addition, methods for forming drop lids include thermoforming such as vacuum forming and pressure forming,
Press molding etc. are used. Even when such a drop lid is used, it is easy to open, so even if the contents overflowing when the drop lid is set are attached to the heat sealing part, the heat sealing temperature and pressure can be increased to prevent the contents from overflowing when the drop lid is set. It is possible to increase the seal strength and obtain high sealing performance.

The material of the container body used in the present invention is not particularly limited, and may include polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyamide resins, polyester resins, polycarbonate resins, ethylene-vinyl alcohol copolymers, Examples include polyvinylidene chloride resin, polyacrylonitrile, mixtures thereof, resins containing 5 to 70% by weight of thermoplastic elastomers, various additives, or inorganic fillers, metals, and paper.

For the purpose of improving gas barrier properties and reducing deformation when used as a container, the container body of the present invention may be made of a multilayer material having two or more layers of other materials laminated. Examples of the layer made of other materials include resin layers such as ethylene-vinyl alcohol copolymer, polyvinylidene chloride, nylon, and polyethylene terephthalate, and materials with excellent gas barrier properties such as aluminum vapor deposited layers and aluminum foil. Furthermore, it may be a composite material with paper or the like.

The number of layers made of these other materials may be one or two.
It may be a multilayer body consisting of more than one layer, or it may be a resin layer containing 10 to 80% by weight of an inorganic filler.

The resin container body is formed by molding a plastic sheet, coextrusion multilayer sheet, or laminate sheet obtained using the above-mentioned resin by vacuum forming, pressure forming, etc., or by injection molding, injection blow molding, blow molding, etc. It can be obtained by molding. Furthermore, it can also be obtained by thermoforming a multilayer film on the inside of a container such as paper.

As the lamination process, methods such as extrusion lamination, hot melt lamination, dry lamination, and wet lamination can be used.

Moreover, a composite container of paper, metal, and resin can be obtained by forming a container body by adhesion, seaming, or the like.

[Effect]

When a product is sealed in the easy-to-open packaging container of the present invention and a multilayer lid is heat-sealed, the package can be easily opened by the following operations.

For example, in FIG. 4, the knob 8 is lifted upward. Then, peeling starts at the concave portion 7 between the innermost layer 2 of the multilayer lid material and the layer 1 in contact with it, and then peeling progresses between the innermost layer 1 of the heat-sealed portion and the layer 2 in contact with it. Then, the innermost layer peels off up to the recess 6,
Next, the entire lid material is opened from point 6. Therefore,
To easily open a multilayer lid material and a container body even if they are heat-sealed with good sealing performance and difficult to peel. Further, sealing conditions such as seal width can be freely set, and even if the seal is misaligned, ease of opening will not be impaired.

As a result, the package is easy to open and can be peeled off even if the peel strength of the heat seal is increased, resulting in an excellent easy-open package that is particularly resistant to boiling and retort processing. Furthermore, by replacing only the heat seal ring, it can be applied to containers of any shape or material, so its use and application range is very wide.

〔Example〕

EXAMPLES Next, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to these examples in any way.

Example 1 A high-density polyethylene sheet having a thickness of 800 .mu.m was subjected to vacuum and pressure forming to form a flanged container having a lip of 80 mm φ x 40 nm (height).

This container was covered with a drop lid as shown in Fig. 5 obtained by thermoforming a multilayer sheet made of ethylene-vinyl acetate copolymer/polypropylene (inner layer/outer layer, 25μ/200μ) as a lid material, and the flange portion As shown in Figure 2, a seal ring of = 5m and h = 50μ is used, and the temperature is 17
Heat sealing was performed at 0 °C and a pressure of 2 kg/cnl for 2 seconds. Note that the thickness of the innermost layer of the lid material in the concave portion obtained by heat sealing was substantially zero.

When the lid material of the thus obtained sealed container was opened, the multilayer lid material peeled off between the eyebrows and could be easily opened.

Example 2 Ionomer/polyethylene terephthalate (inner layer/outer layer, 20μ
/100μ), and cover with a film-like lid material made of a multilayer sheet, and the flange part becomes as shown in Figure 2 = 6
Heat sealing was performed for 2 seconds at a temperature of 170° C. and a pressure of 2 kg/− using a seal ring of fl, t=2 dragons, and h=40 μ. Note that the thickness of the innermost layer of the lid material in the concave portion obtained by heat sealing was substantially zero. When internal pressure was applied to this container using a pump, the lid material swelled in a convex shape starting from point A, but no peeling occurred on the heat-sealed surface.

When the lid material of the thus obtained sealed container was opened, the layers of the multilayer lid material were peeled off and the container could be easily opened.

〔Effect of the invention〕

The present invention has excellent characteristics such as high seal strength, excellent sealing performance, easy opening, good appearance on the peeling surface, and the ability to be boiled or retorted. It is possible to obtain a packaging container, and it is easy to manufacture because it only needs to be sealed with a heat seal ring, and no special equipment is required. Since there is no restriction and the seal width can be arbitrarily set, the practical value of the present invention is extremely large.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing heat sealing in an embodiment of the easy-to-open packaging container of the present invention;
3 and 3 are partial sectional views of other embodiments of the easy-to-open package of the present invention, and FIG. 4 is a partial sectional view showing the state of the container shown in FIG. 3 after being opened. FIG. 5 is a cross-sectional view of the lid and container when the multilayer lid is a drop lid in the present invention. 6th
The figure is a partial sectional view of the packaging container previously filed by the present inventors, and FIG. 7 is a partial sectional view showing the packaging container in its unsealed state. In the figure, numeral 1 is a layer in contact with the innermost layer of the multilayer lid material, 2 is the innermost layer, 3 is the container body, 4 is the container flange portion, and 6 and 7 are concave portions.

Claims (1)

[Claims] 1. In a packaging container formed by heat-sealing a multilayer lid to a container flange, the innermost layer of the multilayer lid and the layer in contact therewith are formed to be releasable, and the inside of the seal and An easy-open packaging container characterized in that a concave portion is formed in the innermost layer of the outer lid material by pressing. 2. The easy-open packaging container according to claim 1, wherein a concave portion is formed by pressing in the innermost layer of the lid material inside the seal portion, with a non-heat seal portion in between. 3. A multilayer lid material in which the innermost layer and the layer in contact with the innermost layer are releasably formed on the container flange, and the innermost layer is a thermoplastic resin layer having a lower melting point or softening point than the material of the layer in contact with the innermost layer. A method for producing an easy-to-open packaging container, which comprises heat-sealing the above using a seal ring having convex portions on the inner and outer peripheral edges. 4. The method for manufacturing an easy-open packaging container according to claim 3, wherein heat sealing is performed using a seal ring having a non-pressing portion on the inner circumference of the heat sealing surface.