JPH0655631B2 - Easy-open packaging - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improved easy-open packaging body. More specifically, the present invention relates to an easily openable package which has excellent sealing property, high pressure resistance, withstands sterilization treatment by boiling or retort, and has good opening and peeling property.

[Conventional technology]

2. Description of the Related Art Conventionally, injection molding containers and thermoforming containers of thermoplastic resins, particularly polyolefin resins, have been used for packaging of many foods by taking advantage of characteristics such as excellent strength and heat resistance. The most common packaging container is a cup-shaped container having a flange portion, which is heat-sealed with a lid material to seal the contents. In this case, if the heat sealing strength is increased in order to improve the sealing property of the container, the unsealing property at the time of use is deteriorated, which is not practical. In order to solve this problem, attempts have been made to deal with the selection of resin combination and resin blend of the seal layer, however, none satisfying these contradictory requirements has been obtained. This is because the heat-sealing strength depends not only on the resin itself but also on the sealing conditions such as temperature, pressure and time at the time of sealing and the influence of foreign matters such as filling materials.

On the other hand, in recent years, boiled foods and retort sterilization have come to be carried out, and along with this, higher sealability, heat resistance,
A container having pressure resistance, water resistance, and easy opening property has been demanded.

[Problems to be solved by the invention]

Therefore, the present applicant has previously proposed a new container in which the layers of the multilayer container are used as the opening and peeling layer, but this container is misaligned at the time of heat sealing and a cutting line (cut) to the flange portion of the container.
In terms of processing, it was not always satisfactory.

Under the circumstances, the present invention is excellent in hermeticity and pressure resistance, withstands boiling or retort sterilization treatment, is not affected by heat seal deviation, and is comparable to conventional containers in peeling and opening. The purpose of the present invention is to provide an easy-open package having properties.

[Means for solving problems]

That is, the present invention, in a packaging body having a peelable sealing portion that is heat-sealed via a heat-sealing material, each packaging material on both sides of the heat-sealing material is bonded so that the adhesive strength with the heat-sealing material is different. , So that the inner edge of the heat-sealing part of the packaging material to which the heat-sealing material is strongly adhered is positioned more outside of the package than the inner edge of the heat-sealing part of the packaging material to which the heat-sealing material is weakly adhered. It is intended to provide an easy-open package which is characterized in that a non-fusing layer is formed.

Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a partial cross-sectional view of an example of a peelable opening part in the case where the easily openable package of the present invention heat-seals a container and a lid material at a container flange part.

In FIG. 1, the lid material 1 and the heat seal material 2 are adhered to each other via the difficult-to-peel adhesive portion 4, and the heat seal material 2 is adhered to the container body 3 via the easily peelable adhesive portion 5. Has been done. The adhesive force of the adhesive portion 4 is larger than the adhesive force of the adhesive portion 5, and 6 is a heat non-fusion layer. With this heat non-fusion layer, the inner end of the heat seal portion of the lid member is formed outside the inner end of the heat seal portion of the container.

The width t of the heat non-fusion layer is 1 mm or more, and usually 1 to 10 m.
It is selected in the range of m, preferably 2 to 10 mm. In the package of the present invention, by providing such a heat non-fusion layer, the increased internal pressure is concentrated at the point A in the boiling or retort sterilization process, so that peeling is less likely to occur on the heat seal surface.

Regarding the adhesive strength of the easily peelable adhesive part 5, it is necessary to have an appropriate peelability, and the interlaminar peel strength is usually 1.5 kg / 15 mm or less (pulling speed 300 mm / min, the same below), preferably It is desirable to set it to 1.3 kg / 15 mm or less. On the other hand, the adhesive force of the adhesive portion 4 between the lid member 1 and the heat seal material 2 needs to be larger than the adhesive force of the easily peelable adhesive portion 5, and the interlayer peel strength thereof is usually 2.0.
It is desirable that the pressure is set to kg / 15 mm or more, preferably 2.5 kg / 15 mm or more.

The base material of the lid material 1 is not particularly limited, and a material normally used for a lid material in a boiling or retort sterilization treatment packaging container can be used, and specifically, a single-phase sheet, a multi-layer sheet, paper, aluminum or the like. Foil and their composite materials are used.

On the other hand, the shape of the container body 3 is not particularly limited, and is usually a cup shape such as a circle or a square, or a tray shape, and is heat-sealed in an annular shape along the flange portion of the container.

The base material of the container body 3 is not particularly limited, and a polyolefin resin, a polystyrene resin, a polyamide resin, a polyester resin, an elastomer, or a combination thereof can be used. Among them, the polyolefin resin is It is suitable. Further, the container body 3 may be made of a single-phase material or may be made of a multi-layer material, and when it is made of a multi-layer material, the inner layer of the flange portion is preferably a polyolefin resin.

As the polyolefin resin, for example, a mixed resin of polypropylene resin and polyethylene resin or high density polyethylene resin is suitable. As the polypropylene resin used for the former mixed resin, in addition to a highly crystalline propylene homopolymer, ethylene, butene-
Examples thereof include random copolymers with α-olefins such as 1, pentene-1, 3-methylbutene-1, and 4-methylpentene-1, and mixtures thereof. The random copolymer may be a mixture with homopolypropylene obtained by multistage polymerization. In the above copolymer, it is preferable that the proportion of the copolymerized monomer is 10 mol% or less. Further, these polypropylene-based resins preferably have a melt index in the range of 0.1 to 20.

On the other hand, as the polyethylene resin used for the mixed resin, low density (high pressure method low density polyethylene, linear low density polyethylene, etc.), medium density and any of medium density and high density polyethylene can be used. Also,
In addition to ethylene homopolymer, propylene and butene-
1, pentene-1, 3-methylbutene-1, 4-methylpentene-1, and other α-olefins, or crystalline or low crystalline or amorphous random or block copolymers with vinyl acetate, or mixtures thereof. Etc. can be used. In the above copolymer, the proportion of the copolymerization monomer is preferably 20 mol% or less.
Further, these polyethylene resins preferably have a melt index (MI) in the range of 0.02 to 50 and a density in the range of 0.850 to 0.980 g / cm ³ .

The ratio of the polypropylene resin to the polyethylene resin is preferably 50:50 to 9 by weight.
7: 3, more preferably 60:40 to 95: 5.

Furthermore, if desired, a third resin component can be added to the resin mixture to improve its compatibility. For example, modified polyolefin modified with unsaturated carboxylic acid or its derivative, ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, ethylene-
Propylene rubber, ethylene-propylene-diene rubber, polybutene, polyisobutylene, polybutadiene rubber, polyisoprene rubber, atactic poly-4-
Examples thereof include methylpentene-1, styrene-butadiene rubber, acrylonitrile-butadiene rubber, and ion-crosslinked olefin copolymer (ionomer). These may be used alone or in combination of two or more. These third components are preferably used in an amount of 30 parts by weight or less per 100 parts by weight of the polypropylene resin.

On the other hand, examples of the high-density polyethylene resin include ethylene homopolymers and copolymers with propylene and α-olefins such as butene-1, pentene-1, 3-methylbutene-1, and 4-methylpentene-1. And so on. In this copolymer, the proportion of the copolymerization monomer is preferably 10 mol% or less. The high-density polyethylene resin preferably has a density in the range of 0.940 to 0.975 g / cm ³ , and may be a mixture of different densities and molecular weight distributions.

These polyolefin resins may be used as they are to form the container body, but may be used as an outer layer body using other materials for the outer layer for the purpose of improving gas barrier properties and reducing deformation of the container. Good. Other materials include, for example, ethylene-vinyl alcohol copolymer, polyvinylidene chloride, nylon, resin layers such as polyethylene terephthalate, and aluminum vapor deposition layers having excellent gas barrier properties. Further, a resin layer containing 10 to 80% by weight of an inorganic filler may be provided. As a method for producing such a composite resin layer, in addition to the usual coextrusion molding method, a method commonly used for laminating, for example, extrusion lamination, hot melt lamination,
A method such as dry laminating or wet laminating can be used.

In the case of a multilayer container, the container body is obtained by thermoforming a coextruded multilayer sheet such as vacuum forming or pressure forming. In addition,
The molding method of the container body may be multilayer injection molding, multilayer injection blow molding, press molding, or the like.

The thickness of the container body is appropriately selected depending on the purpose of use, but is usually in the range of 20 to 2000 μm. Heat seal material 2
Since it is necessary to heat-seal the container main body 3 so as to be easily peelable, the material is appropriately selected depending on the kind of the material of the container main body at the bonding portion of the heat seal material. As the material of the heat seal material, a mixed resin of the above-mentioned polypropylene-based resin and polyethylene-based resin or a high-density polyethylene resin is preferably used. It is desirable to use a high-density polyethylene resin when it is a mixed resin, and to use a mixed resin of polypropylene resin and polyethylene resin when the material of the container body is a high-density polyethylene resin. In addition to such polyolefin resin, polyester resin, polycarbonate resin, polyamide resin, etc. can be used. The thickness of the heat seal material 2 is usually 2 to 3
00 μm, preferably 5 to 150 μm.

In the package of the present invention, the heat-sealing material 2 is adhered to the lid material 1 via the adhesive portion 4 in a non-peeling manner, and the container body 3
It is heat-sealed easily through the adhesive part 5 and
At this time, it is necessary that the heat non-fusion layer 6 is provided so that the inner end of the heat-sealing portion of the lid member and the container is formed so that the inner end of the heat-sealable portion, which is difficult to peel off, is located outside the flange portion. Is. As the method, for example, as shown in FIG. 1, a heat non-fusion layer 6 is provided on the heat seal material 2 by part coating or pattern printing, and then the heat seal material 2 is applied to the lid material 1 with an adhesive or It may be laminated by heat-sealing or the like so that it is difficult to peel, and then this and the container body 3 are heat-sealed so as to be easily peelable, or a donut shape provided with the heat-non-fusing layer 6 as described above. The heat seal material 2 composed of the film is sandwiched between the lid material 1 and the container body 3 to make the heat seal material 2 and the lid material 1 difficult to peel, while the heat seal material 2 and the container body 3 are easily peeled. You may heat-seal. Further, the lid member 1 having a perforated sealing layer may be heat-sealed to the container main body with the non-fusing layer sandwiched therebetween. This heat-sealing material may be a single-layer body or a multi-layer body.

As the heat non-fusing layer, for example, polyamide resin, polyamide-nitrified cotton copolymer, silicone resin, urethane resin, aminoalkyd resin, wax, etc. can be used. The thickness of the heat non-fusing layer is preferably about 1 to 5 μm.

What has been described above is the case where the adhesive force between the heat seal material and the lid material is larger than the adhesive force between the heat seal material and the container body, but the present invention is not limited to this, and in the opposite case. That is, it is a matter of course that the present invention also includes a case where the adhesive force between the heat seal material and the lid material is smaller than the adhesive force between the heat seal material and the container body.

Next, the case where the package of the present invention is in the shape of a bag will be described. FIGS. 2 (a) and 2 (b) are portions of different examples of the peelable opening portion of the bag-shaped package of the present invention. FIG. 2A is a sectional view, and FIG. 2A shows a case where the heat seal material is a single layer body, and FIG. 2B shows a case where the heat seal material is a double layer body. In FIG. 2 (a), the base material 11 is bonded to the heat seal material 12 via the easy peeling adhesive portion 13, while the base material 11 ′ is bonded to the heat seal material 12 and the difficult peeling adhesive portion 14. Are glued together. The adhesive force of the adhesive portion 13 is smaller than the adhesive force of the adhesive portion 14, and 15 is a heat non-fusing layer, the inner end of the heat-sealable portion having difficulty peeling is more than the inner end of the heat-sealable portion having easy peeling. Is also formed on the outside of the package. Similar to the above, the delamination strength of the adhesive portion 14 is usually 2.0 kg / 15 mm or more,
It is preferably 2.5 kg / 15 mm or more, while the adhesive portion 1
The interlayer isolation strength of No. 3 is 1.5 kg / 15 mm or less, preferably 1.3 kg / 15 mm or less.

The materials of the bag base materials 11 and 11 ', the heat seal material 12 and the heat non-fusion layer, the thickness of the base material, the thickness of the heat seal material,
The width of the heat non-fusing layer, the method of adhering the heat seal material, and the like are the same as in the case of the above-mentioned container. Also, the heat seal material 1
When 2 is composed of a two-layer body as shown in FIG. 2 (b), the side 12 ″ to which the base material is easily peeled is attached to the side 12 ″ to which the base material is easily peeled, and the side 12 ′ to which the base material is easily peeled. If the same material as the base material is used for the base material 11, the heat seal material 1
By heat-sealing 2 and the base material 11 at the same time, the peelable opening part can be easily formed, which is preferable.

Even when the packaging is bag-shaped like this, in the case of a bolster or retort sterilization treatment, as in the case of the above-mentioned container,
Since the internal pressure concentrates on point A, peeling does not occur on the heat-sealed surface.

[Action]

When the package of the present invention in which the product is enclosed and heat-sealed is subjected to a sterilization treatment with a boil or a retort, even if the internal pressure rises,
Since the thermal non-fusing layer is provided on the side between the hard-to-peel layers, the internal pressure is concentrated at point A in FIGS. 1 and 2 (a) and 2 (b). Peeling is less likely to occur with cotton.

When the package is opened, for example, in FIG. 1, the easily peelable adhesive part is peeled off by lifting the knob part upward, so that the package can be easily opened. In addition, in FIG. 2 (a) and FIG. 2 (b), the base material 1
By applying a force in the opposite direction to the non-adhesive end portions of 1 and 11 ', the easily peelable adhesive portion is easily peeled off.

〔Example〕

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Using a multilayer sheet, a multilayer container having an opening diameter of 60 mm, a lower diameter of 50 mm and a height of 25 mm was formed by pressure molding. The inner layer of the flange portion is made of polypropylene resin [Idemitsu Petrochemical Co., Ltd., Idemitsu Polypro E-100G, MI 0.6 g.
/ 10 min] 70% by weight and low density polyethylene resin [Toyo Soda Kogyo KK Petrosene 172, MI 0.3 g]
It was a mixed resin consisting of / 10 minutes and a density of 0.920 g / cm ³ ] 30% by weight.

On the other hand, as a lid material, a two-layer sheet made of oriented nylon (ONY) and polyvinylidene chloride is used as a lid base material, and as a heat seal material, high density polyethylene [Idemitsu Petrochemical Co., Ltd., 440M, MI 0.9 g / 10 min. , Density 0.
A film having a thickness of 80 μm and made of 96 g / cm ² ] was prepared.

A hole having a diameter of 60 mm was opened in this high-density polyethylene, and a 5 mm-wide silicone resin was part-coated as a heat non-fusion layer, and this was adhered to the polyvinylidene chloride side of the lid material. The delamination strength of this product was about 3.0 kg / 15 mm. next,
The lid material laminated with the heat seal material was heat sealed so that the heat seal material was in contact with the flange surface of the container as shown in FIG. The peel strength between the heat seal material and the flange surface was 600 g / 15 mm. The container was filled with water and heat-sealed.

The package thus obtained was subjected to retort treatment at 120 ° C. for 30 minutes, but the seal portion did not peel off during the treatment.

Further, this package could be easily sealed by lifting the knob part upward.

Example 2 A mixed resin made of the same polypropylene resin and low density polyethylene resin as in Example 1 was extruded to give a thickness of 120.
A base film of μ was obtained. On the other hand, as a heat-sealing material, a laminated film having a thickness of 80 μm and made of the above-mentioned mixed resin and the high-density polyethylene used in Example 1 was prepared by coextrusion molding.

On the mixed resin side of this laminated film, a 5 mm width silicon resin was part-coated as a heat-non-fusing layer, and the two above-mentioned substrate films were superposed on each other at 180 ° C. Heat sealing was performed to prepare a water-filled bag-like package having a peelable opening as shown in FIG. 2 (b). The interlayer peel strength between the mixed resin layer of the laminated film and the base film is 3.5 kg / 15 mm, while
The delamination strength between the high-density polyethylene layer of the laminated film and the base film was 700 g / 15 mm.

The package was subjected to retort treatment at 120 ° C. for 30 minutes, but no bag was broken. The peeled surface was clean and could be easily opened.

〔The invention's effect〕

The easily openable package of the present invention has excellent sealing properties and pressure resistance, withstands boiling or retort sterilization treatment, is not affected by heat seal shift, and has peeling openability comparable to conventional containers. It has excellent features such as
Extremely high practical value.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of an example of a peelable unsealing part in the container-shaped package of the present invention, and FIGS. 2 (a) and 2 (b) are peeling in the bag-shaped package of the present invention, respectively. FIG. 3 is a partial cross-sectional view of a different example of the heat-sealing portion, in which reference numeral 1 is a lid material, 2 is a heat sealing material, 3 is a container body, 4 is a non-peeling adhesive portion,
Is an easily peelable adhesive part, 6 is a heat non-fusion layer, 7 is a knob part, 1
1 and 11 'are base materials, 12 is a heat seal material, 12'
And 12 ″ are the constituent layers of the two-layer heat seal material,
Reference numeral 13 is an easily peelable adhesive portion, 14 is a difficult peelable adhesive portion, and 15 is a heat non-fusion layer.

Claims (1)

[Claims] 1. A packaging body having a peelable opening part that is heat-sealed via a heat-sealing material layer, wherein the packaging materials on both sides of the heat-sealing material are bonded so that the adhesive strength with the heat-sealing material is different. , So that the inner edge of the heat-sealing part of the packaging material strongly adhered to the heat-sealing material is located outside the inner side of the inner edge of the heat-sealing part of the packaging material weakly adhered to the heat-sealing material. An easily-openable package characterized in that a non-fusing layer is formed.