JPS5946863B2 - packaging - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a package, and particularly to a package that is extremely easy to open and that also has anti-pollution and high-pressure sterilization properties.

Conventional packages using plastic laminated membranes that are sealed by heat sealing have the following configurations.

For example, as shown in FIG. 1, two laminated films using a heat-sealable film such as polyethylene as the innermost layer 1 are stacked one on top of the other, and a heat-sealed portion is provided and sealed.

However, it was very troublesome to open this package because the heat seal strength was high. Therefore, in order to improve this problem, a package has been considered in which the thickness of the innermost layer film 1 is reduced and the breaking strength of the innermost layer film 1 is smaller than the heat sealing strength of the innermost layer films 1 to each other. However, even in this package, the heat-sealed portion was not opened and the innermost film 1 was broken as shown in FIG.
Therefore, in order to open the package, the innermost layer film 1 had to be broken by the width of the heat-sealed portion a, and no major improvement could be expected. In addition, in order to make opening easier, a package has been considered in which the innermost layer film 1 is heat-sealed with films made of different resins, such as polyethylene and polypropylene films, and the heat-sealing strength is very low. Such packaging has a narrow range of suitable heat sealing and is inferior in terms of pole resistance, high pressure sterilization resistance, etc., and has the disadvantage that the contents that can be packaged are limited. Was. The present invention eliminates the drawbacks of these conventional packages made of laminated films, and provides a package that is easy to open and also has pole resistance and high-pressure sterilization resistance.

The present invention will be explained in detail below. The present invention has a coextruded film consisting of a first layer 2 having a thickness of about 15μ and a second layer 3 thicker than the first layer 2, as shown in FIG. The peel strength with 3 is greater than the breaking strength of the first layer,
A laminate having a synthetic resin or adhesive resin layer 5 in which the sealing strength between the sealed body 4 having a width of 30 to 2009/15 mm and the first layer 2 of the sealed body 4 is greater than the breaking strength of the seal portion of the first layer 2. After filling the contents, the base body 6 and the first layer 2 of the sealing body 4 are superimposed and the periphery is heat-sealed. As shown in FIG. 2, the package is heat-sealed with one or several protrusions 7 provided on the outside of the surrounding heat-sealed portion.

This protrusion piece 7 has one acute-angled protrusion as shown in FIG. 5, or two protrusions with branched tips as shown in FIG. 6.

If a protruding piece having such a shape is provided, if the protruding piece is opened first when opening the package, the first layer is torn along the seal width, and the seal can be opened cleanly and easily.

Here, there are the following combinations of the first layer 2 and the second layer 3.

Rubber-added polypropylene/medium density polyethylene,
High-density polyethylene/polypropylene with added rubber,
There are combinations of polypropylene/ethylene monovinyl acetate copolymer, polypropylene+ethylene monovinyl acetate copolymer/high density polyethylene, and nylon/ionomer resin.

Here, not only is the former the first layer and the latter the second layer, but the reverse is also possible.

Here, polypropylene is homopolymer, ethylene
Either a propylene copolymer or a mixed resin of polyethylene and polypropylene.

Examples of rubber include polyisobutylene, ethylene-propylene, elastomer, and styrene-butadiene rubber. The thickness of the first layer 2 is preferably approximately 15 μm; if the thickness is greater than this, the first layer cannot be easily broken at the heat-sealed portion, making it difficult to open the package.

The heat-sealing resin layer is provided by coextrusion molding together with the first layer and the second layer, and is formed by extrusion coating on the surface of the first layer after forming the first layer and the second layer by coextrusion molding.

The shape of the package of the present invention is not only a bag-like one as shown in FIG. 3, but also one in which the base is molded and the sealed body is used as a lid for a deep-drawn container.

The package of the present invention is opened in the state shown in FIG.

That is, the first layer ruptures at the boundary between the heat-sealed part and the non-heat-sealed part of the package of the present invention,
At the heat-sealed portion, the first layer and the second layer are peeled off and opened. This is because the heat-sealing strength between the first layer 2 and the base 6 is greater than the breaking strength of the first layer 2, so when the sealing body 4 is separated, the L layer breaks first at the outer boundary of the heat-sealed part. .

In the heat-sealed portion, the heat-seal strength of the first layer and the second layer is lower than the heat-seal strength of the first layer and the base, so that the first layer and the second layer separate. Next, at the inner border of the heat-sealed portion, the first layer ruptures as at the outer heat-sealed portion, and the package is opened.

Conventionally, it was necessary to break all the heat-sealed parts, but the package of the present invention can be opened simply by breaking at the boundary between the heat-sealed part and the non-heat-sealed part, so it can be opened easily.

Furthermore, the peel strength of the first layer and the second layer is 30~2009/1
Since it is 5 times long, it will not peel off even after boiling or high-pressure sterilization, so the restrictions on the contents have been greatly reduced.

<Example 1> Polypropylene with a density of 0.905 87% by weight styrene butadiene 10% by weight phenyl-β-naphthylamine (antioxidant) 1% by weight stearamide (lubricant) 1% by weight phthalate ester (plasticizer)
Mixed polypropylene 2 mixed in the above ratio of 1% by weight and medium-low pressure polyethylene 3 having a density of 0.956 are coextruded to form two-layer films having thicknesses of 15 μm and 50 μm, respectively.

Next, three polyethylene faces of the two-layer film are corona-treated and bonded to a 35 μm polyester film (not shown) using an isocyanate adhesive to form a three-layer film. Then, as shown in FIG. 5, this three-layer film is cut into a shape having a plurality of peripheral protrusions 7 to form a lid. Finally, another deep-drawn plastic tray whose inner surface is covered with polypropylene resin 5 is filled with the contents 8, and then the lid is placed and the periphery is heat-sealed to a desired width 9. The package filled with contents 8 obtained in this way was sterilized with foil for 95 to 60 minutes, but there was no peeling between the mixed polypropylene 2 and polyethylene 3 layers, and there was no difference between the heat-sealed part and the non-heat-sealed part. The mixed polypropylene film did not break at the boundary and was extremely excellent.

The package could be opened very easily by lifting the deep drawing tray by the pusher protrusion, as the seal was broken in the direction of the arrow b shown in FIG. In addition, mixed polypropylene 3 and polyethylene 2 were stacked in the opposite direction to the above package by a co-extrusion method to form two-layer films having a thickness of 50 μm and 15 μm, respectively, and a 35 μm polyester film was placed on the mixed polypropylene 3 surface (Fig. A package was also produced at the same time, in which two sides of polyethylene were placed on a plastic deep-drawn tray whose inner surface was covered with polyethylene 5 and heat-sealed, but similar results were obtained. <Example 2> Low-pressure polyethylene with a density of 0.952 72% by weight styrene butadiene rubber 25% by weight phenyl β-
Naphthylamine (antioxidant) 1% by weight Stearamide (lubricant) 1% by weight Phthalate ester (plasticizer) 1% by weight Polyethylene 3 and polypropylene 2 with a density of 0.905 mixed in the above ratio are coextruded. A two-layer film having a thickness of 30 μm and 15 μm, respectively, was formed using the above method, three surfaces of the polyethylene were subjected to corona treatment, and an aluminum foil laminated film was prepared using an epoxy adhesive.

Next, this aluminum foil laminated film was cut into a shape having two protruding pieces 7 for opening as shown in FIG. Place the polypropylene on an aluminum can with two sides facing down, and heat seal the periphery with an arbitrary width 9 as in Example 1. Regarding the obtained aluminum tray, 1
．． High-pressure sterilization was carried out at 2 atmospheres and 120°C, but the results were excellent, with no peeling between the polyethylene 3 and polypropylene layers, and no breakage of the polypropylene film at the boundary between the heat-sealed and non-heat-sealed parts.

Furthermore, the seal was broken in the direction of arrow c shown in FIG. 6 by pressing one of the two protruding pieces 7 and lifting the other, making it extremely easy to open the package.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a package using a conventional heat-sealable laminated film, and Figure 2 is a cross-sectional view of the package when the package is opened, with an improved version of the package in which the inner heat-seal film has a lower breakage resistance. , 3 to 6 show examples of the present invention, in which FIG. 3 is a cross-sectional view of the package of the present invention, FIG. 4 is a cross-sectional view when the package is opened, and FIGS. 5 and 6. 1 and 2 respectively show plan views of the packaging body of the present invention. DESCRIPTION OF SYMBOLS 1... Innermost layer film, 2... First layer, 3... Second layer, 4... Sealed body, 5...
...Adhesive resin layer, 6...Base, 7...
...Protrusion piece, 8...Contents, 9...
Width, a... Heat seal width, B, c...
Seal direction.

Claims (1)

[Claims] 1 has a coextruded film consisting of a first layer with a thickness of about 15μ and a second layer thicker than the first layer, the peel strength of the first layer and the second layer is greater than the breaking strength of the first layer, ~200g
/15 mm width, and a base body made of a laminate having a synthetic resin layer whose seal strength with the first layer of the seal body is greater than the breaking strength of the first layer, The resin layer and the first layer of the sealing body are overlapped, and a sealing part having one or several protrusions is provided around the periphery, and the base body and the sealing body are peeled off in unsealed parts inside and outside the sealing part. death,
Further, the package has a structure in which the first layer of the sealed body is broken at the boundary between the sealed portion and the unsealed portion, and in the sealed portion, the first layer and the second layer of the sealed body are separated and opened.