JPS591312A - Easy open sealing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] related to how to

Various efforts have been made to ensure easy-open closures for packaging containers made of paper or plastic molded products, and packaging bags made of plastic film that are sealed by heat sealing. There is.

In general, heat-sealing sealants themselves are now available with moderate peel strength, so once you start opening the sealant, it progresses easily, but because the initial peel strength is high, Difficult to start opening.

As one of the measures to improve initial opening, it was proposed to provide a protruding seal with a non-sealing part having an acute angle, especially an acute angle of 75° or less, on the inside (Japanese Patent Laid-Open No. 56-649).
No. 70).

It is easy to understand that the non-sealed part is an acute angle, and that is also 7
In order to provide a protruding seal with a sharp angle of 5° or less, the width of the flange of the container must be wide, at least at the opening portion.

This imposes restrictions on the shape of the container, and conversely, this method of providing easy-opening properties has a narrow scope of application.

As another means to improve initial opening ability, the applicant:
We came up with the idea of creating a seal with a lower seal strength in the opening than in other parts, and have already established and proposed a method for doing so (Japanese Patent Application No. 57-31557).

Further research has led to the discovery that by combining the protrusion seal described above and this sealing technology with selective strength, the effects of both can be enhanced, resulting in the present invention.

Therefore, an object of the present invention is to provide an easy-to-open heat seal that eliminates the need to increase the flange width by making the angle of the protrusion seal obtuse or close to it, and has even better initial opening properties. The goal is to provide a method for

The easy-to-open heat-sealing method of the present invention includes forming a protruding seal having a monogonal non-sealing part on the inside in the opening part;
At that time, heat-sealing is performed using a heat-sealing device in which heat-resistant rubber is embedded in the part corresponding to the unsealing part of the retainer, and the sole strength of the unsealing part is made lower than that of other parts.

Referring to the drawings, an example of a packaging container configured by combining a cup-shaped body 1 and a lid 2 will be explained. As shown in FIG. The protruding seal 31 has a monogonal non-sole part 32 of 80 to 100 mm inside, and the part surrounded by the broken line in the figure is heat-sealed so that the sealing strength is lower than the other part.

As shown in FIG. 2, such heat sealing is performed by applying heat-resistant rubber 41 to the area corresponding to the opening of the adhesive retainer 4 of the heat sealing device, that is, the support base of the flange 11 of the container 1.
This can be achieved by embedding the annular seal 3 in advance and pressing it with a heating blade 5 from above to form the annular seal 3. Since the heat-resistant rubber 41 absorbs and disperses the pressure of the heating blade 5, the peel strength in this area is lower than in other parts where metal is used.

The degree to which the peel strength of the heat seal in the opening area should be reduced varies somewhat depending on the original peel strength given to other parts and the shape of the protrusion seal, but for sufficient initial opening properties, it is usually 20 % reduction [7, e.g. 2
This is the second consecutive 4% decrease.

On the other hand, if it is reduced too much, there will be concerns about the sealing performance, so it is best to limit the reduction to about 50%. This adjustment can be made by appropriately selecting the hardness and thickness of the heat-resistant rubber embedded in the retainer.

For example, a 2 to 5 mm thick plate of silicone rubber with a hardness of 50 to 8 oo is used to replace the metal material in the opening area of the retainer.

The present invention is capable of many other embodiments in addition to those described above.
For example, the angle of the tip of the non-sealed part of the protrusion seal is 80
The angle is not limited to ~1oo0, but may be more acute or obtuse. Furthermore, the present invention can be applied not only to containers in which a lid is assembled to the main body of a molded product, but also to packaging bags made of film.

Example 1 PET12μ10 in a cup-shaped body made of polypropylene
A lid having a composition of 15μ of N/60μ of sealant (PET is made of polyethylene terephthalate, ON is made of stretched nylon) was heat-sealed with a protrusion seal having an α-near of 8°. At that time, silicone rubber was used in the unsealed area of the retainer.

Peel strength of unsealed part: 1570 (unit: 9/15 mm)
, the same applies hereinafter), and 2113 in other parts (reduction rate of peel strength at unsealing part was about 26%), and an easy-to-open heat seal with excellent initial unsealability was obtained.

Example 2 Example 1 was repeated under the same conditions except that the type of sealant was changed (thickness: 50 μm).

Peel strength of the unsealed part is 2368, and that of other parts is 3075.
(The reduction rate was about 23%), and in the case of , an easy-to-open container with good initial opening properties was also produced.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway plan view of a lid showing an example of a container that has been heat-sealed for easy opening by the method of the present invention. FIG. 2 is a sectional view illustrating the easy-open heat sealing method of the present invention. 1. Container body 2. Lid body 3. Heat seal 31. Protrusion seal 32.. Non-sealed part 4.
Retainer 41...Heat-resistant rubber patent applicant Dai Nippon Printing Co., Ltd.

Claims (4)

[Claims] (1) A method of applying an easy-to-open heat seal to a container, in which a protruding seal having a monogonal non-sealing part on the inside is formed on the opening part, and at that time, the seal contacts the opening part of the glue retainer of the heat sealing device. A sealing method characterized in that heat sealing is performed using a device in which heat-resistant rubber is embedded in the portion, and the sealing strength of the unsealed portion is lower than that of other portions. (2) The sealing method according to claim 1, in which the sealing strength of the unsealed part is lowered by 0 to 50 degrees compared to other parts. (3) - The angle of the tip of the square non-sealed part is 80 to 10
The sealing method according to claim 1, wherein the range is 0°. (4) The sealing method according to claim 1, wherein the container is composed of a main body and a lid, and the lid is heat-sealed to a seven-lung portion of the main body.