JPS6137647Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a drop lid for easy-open sealed packaging.

Traditionally, heat-resistant lid materials have been used that have a base material such as oriented polyethylene terephthalate, oriented nylon, or oriented polypropylene, with a heat sealing material layer on one side. Because the base material is stretched, it is difficult to mold it into a shape to form a heat-resistant drop lid.

The inventor of the present invention was able to perform liquid sealing over a wide temperature range (180 to 240°C) and heat sterilization. There is no
In addition, as a result of research to develop a drop lid that can be easily opened, the top layer made of heat-resistant resin,
A laminate consisting of three layers, an intermediate layer made of polypropylene, and a cohesive failure sealant layer made of a polypropylene-polyethylene blend polymer laminated under the intermediate layer, can be molded into the shape of a drop lid, and is heat resistant. It was discovered that the top layer made of resin completely prevents the lid surface from sticking to the seal bar during heat sealing and from deforming the lid during heat sterilization treatment, and based on this knowledge, the present invention was developed. This is the completed version.

That is, the gist of the present invention is a laminate consisting of three layers: an uppermost layer made of a heat-resistant resin, an intermediate layer made of polypropylene, and a cohesive failure sealant layer made of a polypropylene-polyethylene blend polymer laminated below the intermediate layer. This is an easy-to-open drop lid made by molding a material into the shape of a drop lid.

Hereinafter, the present invention will be explained in detail with reference to the drawings.

FIG. 1 shows an easy-to-open drop lid according to the present invention.

The easy-to-open drop lid 1 according to the present invention is a laminate material 5 consisting of three layers: a top layer 2 made of a heat-resistant resin, a middle layer 3 made of polypropylene, and a cohesively fracturing sealant layer 4 made of a polypropylene-polyethylene blend polymer laminated under the middle layer 3.
It is formed into the shape of a drop lid.

In the present invention, the uppermost layer 2 made of heat-resistant resin may be made of heat-resistant resin such as nylon, polycarbonate, and polybutylene terephthalate.

This top layer 2 provides shape retention and rigidity to the molded lid so that it does not deform, and is also heat resistant to the extent that the top surface of the lid does not come into close contact with the hot plate when the lid is heat-sealed to the container body. It is necessary to impart properties to the lid, and its thickness is preferably 20 to 100 μm. When the thickness is less than 20 μm, the laminated material loses its rigidity, so the shape retention when forming the lid is poor, and the lid may be deformed during heat sterilization treatment, which is not preferable. A thickness of 100 μm or more is not preferable because it increases costs.

Next, the intermediate layer 3 made of polypropylene is necessary to impart moldability to the laminated material constituting the lid. The thickness of this intermediate layer 3 is preferably 30 to 150 μm, most preferably 50 to 100 μm.

When the thickness is less than 30μ, it is not preferable because the suitability for thermoforming such as vacuum forming and pressure forming becomes poor, while when it is more than 150μ, it is not preferable because it increases the cost. Further, the reason why 50 to 100μ is particularly optimal is that it has excellent thermoformability in vacuum forming, pressure forming, etc., and because of the flexibility of polypropylene, there is no uneven sealing during sealing and uniform peeling can be obtained.

Next, as the cohesive failure sealant layer 4 made of a polypropylene-polyethylene blend polymer, a blend polymer of high density polyethylene and polypropylene is suitable from the viewpoints of both heat resistance and ease of cohesive failure. The preferred mixture ratio of polypropylene and polyethylene is 30-70% by weight of polypropylene and 70-30% by weight of polyethylene. Good easy-opening properties cannot be obtained outside this mixture ratio range.
The best ease of opening is obtained when the polypropylene and polyethylene are 50% by weight. The thickness of the cohesive failure sealant layer is preferably 20 to 50μ. If it is less than 20μ, the opening strength after heat sealing is less than the practical strength, and the risk of breakage during distribution and storage increases, which is not preferable. On the other hand, if it is more than 50μ, not only will the cost increase, but the opening strength after heat sealing will exceed the practical strength, and excessive force will be required to open the package, which is not preferable.

In the present invention, the sealant layer is made of a cohesive failure sealant layer made of a polypropylene-polyethylene blend polymer, so it can seal in a wide temperature range (180 to 240 degrees Celsius).
Moreover, even if heat sterilization is performed, the heat seal strength is not affected by the heat sterilization treatment. Furthermore, the condition of the flange portion of the container body after opening is also good, with no stringiness or the like.

Next, in the present invention, the laminated material 5 is the uppermost layer 2.
The intermediate layer 3 and the cohesive failure sealant layer 4 are formed by dry laminating using an adhesive such as an isocyanate adhesive or an epoxy adhesive.

Next, in the present invention, the laminated material 5 can be formed by thermoforming methods such as vacuum forming and pressure forming.

FIG. 2 is a partially sectional side view showing a container sealed with the easy-to-open drop lid of the present invention. In the figure, 6 indicates the tongue piece of the easy-to-open drop lid, 7 indicates the container body, and 8 indicates the packaged item.

The drop lid of the present invention can be opened extremely easily by holding the tongue piece 6 and pulling the lid 1 out of the container body 7.

FIG. 3 shows a state in which after the container main body 7 is sealed using the drop lid 1 of the present invention, a secondary packaged object 9 is accommodated in the upper recess 8 of the lid, and then an upper lid 10 is attached.

As detailed above, the drop lid of the present invention includes an uppermost layer made of a heat-resistant resin, an intermediate layer made of polypropylene, and a cohesive failure sealant layer made of a polypropylene-polyethylene blend polymer laminated below the intermediate layer. Since it is made of a three-layer laminated material molded into the shape of a drop lid, it can be sealed over a wide temperature range, and can be heat sterilized, as well as heat-sealing strength. It is not affected by sterilization treatment, can be opened easily, and the flange of the container body is in good condition without stringiness after opening.

Further, according to the drop lid of the present invention, the secondary packaging item can be accommodated in the upper recess of the drop lid, so that the main packaging item and the secondary packaging item can be packaged together.

Next, the present invention will be specifically explained with reference to Examples.

Example 1 Unstretched nylon film 30μ, unstretched polypropylene film 70μ, polypropylene-polyethylene blend polymer film 30μ (polypropylene; random copolymer with 50wt% ethylene content 3.5%, density 0.90, MI=6.0, polyethylene;
50wt%, density 0.96, MI=0.2) were laminated in this order using an isocyanate adhesive, and this laminated material was vacuum formed to form a drop lid. Next, this lid was heat-sealed to a polypropylene container containing jelly at 200°C. This was retort sterilized at 120°C for 30 minutes, but no abnormality was observed in the lid.

Furthermore, the container could be opened easily, and the flange of the container body was in good condition with no stringiness after opening.

Example 2 Polycarbonate 80μ, unstretched polypropylene film 50μ, polypropylene-polyethylene blend film 30μ (polypropylene; 50wt%
Random copolymer with 3.5% ethylene content, density
0.90, MI=6.0, polyethylene; 50wt% density
0.96, MI=0.2) were laminated in this order using an isocyanate adhesive, and this laminated material was vacuum formed to form a drop lid. Next, this lid was heat-sealed to a polypropylene container containing jelly at 200°C. This was retort sterilized at 120°C for 30 minutes, but no abnormality was observed in the lid.

Furthermore, the container could be opened easily, and the flange of the container body was in good condition with no stringiness after opening.

Example 3 Polybutylene terephthalate 80μ, unstretched polypropylene film 50μ, polyaropylene-polyethylene blend film 30μ (polypropylene; 50wt% Random copolymer with ethylene content 3.5%, density 0.90, MI=6.0, polyethylene; 50wt%
(density 0.96, MI=0.2) were laminated in this order using an isocyanate adhesive, and the laminated material was vacuum formed to form a lid. Next, this lid was heat-sealed at 200°C to a polypropylene container containing jelly. This was retort sterilized at 120°C for 30 minutes, but no abnormality was observed in the lid.

Furthermore, the container could be opened easily, and the flange of the container body was in good condition with no stringiness after opening.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the easy-to-open drop lid of the present invention, Fig. 2 is a partially sectional side view of the container main body sealed with the drop lid of the present invention, and Fig. 3 is a side view of the main cover using the drop lid of the present invention. FIG. 2 is a partially sectional side view showing a state in which a subpackaged object is packaged together with a packaged object. 2... Top layer, 3... Intermediate layer, 4... Cohesive failure sealant layer, 5... Laminated material.

Claims (1)

[Scope of utility model registration request] A laminated material consisting of three layers: a top layer made of a heat-resistant resin, an intermediate layer made of polypropylene, and a cohesive failure sealant layer made of a polypropylene-polyethylene blend polymer laminated below the intermediate layer is formed into the shape of a drop lid. Easy-to-open drop lid.