JPS63162444A - Shrink packaging 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] [Industrial application field] The present invention relates to a shrink packaging method.

[Problems to be solved by the prior art and the invention] After covering the packaged item with a heat-shrinkable film, the heat-shrinkable film is shrunk by heating, and the film is brought into close contact with the packaged item for packaging. The so-called shrink packaging method has been widely used in recent years to package products such as foods, daily necessities, and miscellaneous goods.

In the shrink packaging method, holes or cuts are usually required to exhaust the air trapped inside the package when the heat-shrinkable film is compressed by heating.
For this purpose, conventionally, as shown in FIG.
] After coating the packaged product 4 with the film 1 (Fig. 1(b)), the film 1 is heated to form a film 1.
The film J11 was shrunk to bring the film J11 into close contact with the packaged product 4 for packaging (FIG. 1(C)). However, with the conventional method, it is difficult to control the size of the holes 3, and there are many drawbacks such as holes that are larger than necessary, holes that are too small, and the air exhaust efficiency is poor, making packaging work time-consuming. there were.

[Means for solving problems]

The present invention has been made in view of the above-mentioned drawbacks of the conventional method, and allows air exhaust through holes to be provided easily and accurately.
It is an object of the present invention to provide a shrink packaging method that can easily and reliably perform an evacuation operation in a heat shrinking process of a heat shrinkable film.

That is, the present invention covers an item to be packaged with a packaging film made by partially applying a heat-generating substance that generates heat by microwaves to a heat-shrinkable base material, and then irradiates the product with microwaves to form a heat-shrinkable base material. The gist of the present invention is a shrink packaging method, which is characterized in that a through-hole is formed at a location where a pyrogenic substance (F) is present, and then the heat-shrinkable base material is shrunk by heating.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 2 shows an example of the packaging film 11 used in the present invention, and this packaging film 11 has a heat absorption rate of 11? It is constructed by partially providing a heat generating layer 13 on the surface of an i-type base material 12. The heat-shrinkable base material 12 can be composed of a uniaxially stretched film 1 or a biaxially stretched film whose base resin is polyethylene, polypropylene, polyvinyl chloride, nylon, polyethylene terephthalate, or the like. The heat-generating layer 13 can be composed of a metal thin film formed on the base material 12 by plating, vacuum deposition, sputtering, or the like with a metal such as aluminum, iron, nickel, or copper.

In addition, exothermic 113 is produced by printing a conductive ink or paint containing a reduced potassium titanate whisker or a mixture of this and a conductive substance by a known method, or by printing or coating a resin with this conductive ink or paint. The conductive material may be formed by cutting a sheet, film, etc. and laminating it on the heat-shrinkable base material 12. The conductive material may be a metal powder such as aluminum, iron, nickel, or copper, or a nonmetal such as carbon powder. Examples include conductive material powder. Exothermic N13 has an electrical resistivity of 0.4 to 4゜Ω/□, especially 1-
It is preferable to configure the resistance to 10Ω/□.

The method of the present invention covers the packaged product 14 with the film 11 as shown in FIG. generates heat and the heat-shrinkable base material 12
A through hole 15 is formed at a location where the upper heat generating layer 13 is provided (FIG. 3(C)).

Next, heat is applied to shrink the heat-shrinkable base material L2 (i.e.,
By shrinking the packaging film 11), the film 11 comes into close contact with the packaged product 14, as shown in FIG. 3(b), and shrink packaging is completed.

In the method of the present invention, the through holes 15 can be provided in a shape corresponding to the pattern of the heat generating layer 13.
By arbitrarily adjusting the pattern of heat generating layer 3, such as making the pattern of the heat generating layer 13 circular or elongated, the pattern of the heat generating layer 13 can be changed to an arbitrary pattern depending on the size, or a pattern of large size. A through hole 15 can be provided. Further, by appropriately adjusting the location where the heat generating layer 13 is provided, the through hole 15 can be provided in a particularly inconspicuous location of the package.

In the above example, a case was explained in which a packaging film was used in which a heat-generating layer made of a pyrogenic substance was provided on the surface of a heat-shrinkable base material. You may use the film.

The present invention will be explained in more detail below with reference to specific examples.

Example 1 A polyethylene terephthalate film with a thickness of 12p, on which aluminum was vacuum-deposited to form an aluminum-deposited layer with an electrical resistivity of 2Ω/□, was cut into 5°ζ pieces and pasted onto a biaxially stretched shrinkable polypropylene film. After wrapping a spherical packaged product with a diameter of 5 cm in a packaging film on which a heat-generating layer was formed, it was placed in a 500W microwave oven. When the packaging film was heated for 5 minutes in an oven at 150°C with a through hole of φ drilled, the packaging film collapsed!
i? At the same time, the air inside the package was effectively exhausted through the through holes, and a shrink package in which the film was in close contact with the packaged product was obtained.

Actual h (1! Example 2 A pattern of Q, 5 mmφ was printed at IO dragon intervals on a biaxially stretched shrink polypropylene film of 50 μm thickness using conductive ink containing reduced potassium titanate whiskers and Kechieran black. After packaging the same packaging as in Example 1 using a packaging film with the entire heat-generating outer layer formed, through-holes were punched in a microwave oven and the film was heat-shrinked under the same conditions to shrink packaging. When the film was heat-shrinked, the air inside the package was evacuated and the film was shrunk efficiently.Also, this package had small through-holes, so the holes were not noticeable, and it was easy to open. At this time, the through-holes served as guides 11 for cutting the film, making it possible to easily cut the film in a straight line and open it 1.

〔Effect of the invention〕

As explained above, the method of the present invention involves partially applying an exothermic substance that generates heat by one wave of a microphone, covering the packaged item with a heat-shrinkable packaging film, and then irradiating it with microwaves. Because we adopted a method of drilling a through hole for exhaust air at the location where the exothermic substance was applied, the size of the through hole was too large compared to the conventional method of creating the through hole with a needle, etc. To perform efficient shrink packaging by eliminating problems such as being too small, making it possible to easily and reliably provide 11 holes for exhaust, and ensuring exhaust when heat shrinking the film. I can do it.

Moreover, by appropriately adjusting the formation location, shape, size, etc. of the exothermic material fer layer, the size, shape, number, etc. of the through holes can be adjusted arbitrarily, and the exhaust gas can be adjusted according to the purpose. Various effects such as the size, shape, number, etc. of the through holes can be adjusted as appropriate.

[Brief explanation of the drawing]

Fig. 1 is a process diagram of a conventional shrink packaging method, Figs. 2 and 3 show an embodiment of the present invention, Fig. 2 is a longitudinal cross-sectional view of a film used in the present invention, and Fig. 3 is a shrink packaging method of the present invention. It is a process diagram of a packaging method. 11... Packaging film 12... Heat-shrinkable base material
13... Heat generating layer 14... Covering Figure 1 (a) (C) Figure 3

Claims (7)

[Claims] (1) After covering the packaged product with a packaging film made by partially applying a heat-generating substance that generates heat using microwaves to a heat-shrinkable base material, the heat-shrinkable base material generates heat by irradiating it with microwaves. 1. A shrink packaging method characterized by forming a through hole in a location where a sexual substance is present, and then heating to shrink a heat-shrinkable base material. (2) The heat-shrinkable base material is polyethylene, polypropylene,
The shrink packaging method according to claim 1, wherein the base resin is polyvinyl chloride, nylon, or polyethylene terephthalate. (3) The shrink packaging method according to claim 1 or 2, wherein the exothermic substance is a thin metal film. (4) The shrink packaging method according to claim 1 or 2, wherein the pyrogenic substance is a reduced potassium titanate whisker. (5) The shrink packaging method according to claim 1 or 2, wherein the pyrogenic substance is a mixture of reduced potassium titanate whiskers and metal powder. (6) The shrink packaging method according to claim 1 or 2, wherein the pyrogenic substance is a mixture of a reduced potassium titanate whisker and a nonmetallic conductive substance. (7) Electrical resistivity of the exothermic substance layer is 0.4 to 40Ω/□
A shrink packaging method according to any one of claims 1 to 6.