JP2893255B2 - Heat shrink wrapping method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable packaging method using a heat-shrinkable film, and more particularly to a heat-shrinkable packaging method suitably used for obtaining a heat-shrinkable package having excellent airtightness.

[0002]

2. Description of the Related Art Conventionally, as a shrink-wrapping method, an object to be packaged is covered with a heat-shrinkable film, and an open portion is sealed and then passed through a heat-shrinkable tunnel or blown with hot air. A so-called heat shrink packaging method for heat shrinking a film is known. This heat shrink wrapping method is widely used because of its excellent economy, workability, and high speed. By the way, when this method is used for heat shrink wrapping that covers the entire surface of the article to be wrapped, air inside the package covered with the heat shrinkable film must be discharged to the outside during heat shrink wrapping. Preparing a few holes in advance on the heat-shrinkable film surface, or
It has been common practice to degas the air inside the package in advance and then heat shrink the package.

However, when a heat-shrinkable film having a small hole is used for packaging food or the like, air, moisture, bacteria, and the like enter the package through the small hole and oxidize and discolor the food to be packaged. There was a problem that rot and the like occurred, and storage could not be performed for a long time. Further, the heat-shrinkable package having small holes in the heat-shrinkable film also has a problem that a bag is easily broken from the small holes during transportation or the like. In order to solve such a drawback, a method is used in which a heat-shrinkable film is heat-shrink-wrapped in a state where a punch hole for air discharge is opened, and the punch hole is closed with an adhesive label (actually, Kosho 50
-29007) has been proposed. Although this method is effective in solving the above-mentioned drawbacks, it is difficult to automatically attach a label to a position that closes a punched hole, and since it is necessary to have one label for each package, There was a problem that the cost would be expensive.

[0004] A heat-shrinkable packaging method is disclosed in which a moisture-proof sheet is attached to a soft bag, and a packaging bag having an air outlet provided in a heat-shrinkable film is provided at the position of the moisture-proof sheet (Japanese Utility Model Application Laid-Open No. 63-14442). ) Has also been proposed. This method, the moisture-proof sheet attached to the soft bag, between the heat-shrinkable film, when heat shrink packaging, the air between the heat-shrink film and the soft bag is degassed and exhausted, when the packaging is completed, The portion of the air discharge hole on the moisture-proof sheet also adheres to the heat-shrinkable film, and the outside air does not flow from the periphery of the air discharge hole into the soft bag. It has.

However, such a heat-shrinking method uses a double-packaged bag composed of a soft bag and a heat-shrinkable film, so that the packaging operation is complicated and the packaging cost is high. In addition, although the air between the soft bag and the heat shrinkable film can be degassed, there is a drawback that it is difficult to deaerate and discharge the air between the soft bag and the package, and a moisture-proof sheet is attached to the soft bag. A heat-shrink wrapping step and a heat-shrink wrapping step, in which a heat-shrinkable film is positioned at the position of the moisture-proof sheet.
There has been a problem that the number of packaging work steps increases and complicated packaging management is required.

Further, the method of performing heat shrink packaging after evacuating the air in the package has the problem that not only the packaging apparatus is expensive, but also high-speed packaging cannot be performed, and the packaging cost increases.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and to provide a heat-shrinkable package which is excellent in airtightness and which does not easily break during transportation or the like by a simple process at a low cost. It is an object of the present invention to provide a heat-shrinkable packaging method that can be used.

[0008]

The present inventors have conducted intensive studies to solve the above-mentioned problems. As a result, the heat-shrinkable film has, for example, one row or two or three rows of adjacent small holes for air discharge. The heat-shrinkable film is folded back so that one end of the heat-shrinkable film is positioned between the object to be packaged and the heat-shrinkable film so as to close the small hole. Thereby, it is found that the above problem can be solved, and also, when a hot-melt adhesive or a pressure-sensitive adhesive is applied to the surface of the folded portion of the heat-shrinkable film that contacts the heat-shrinkable film, the airtightness is excellent. It has been found that a heat-shrinkable package can be obtained, and furthermore, the use of a film having a gas barrier property as a heat-shrinkable film can preserve an article to be packaged for a long period of time, thereby completing the present invention.

That is, according to the present invention, in a heat shrink wrapping method for wrapping an article to be wrapped 1 using a heat shrinkable film 2, the heat shrinkable film 2 is provided with small holes 3 for discharging air. One end of the heat-shrinkable film 2 is folded so as to cover the small hole 3 so that the folded portion 5 is located between the packaged object 1 and the heat-shrinkable film 2. A heat shrink wrapping method characterized by wrapping the article to be packaged 1 with a wrapper, followed by sealing the open portion and then heating. The heat-shrinkable film 2 is provided with small holes 3 for air discharge in one row or two adjacent rows.
Alternatively, the heat shrink wrapping method is provided, wherein the heat shrink wrapping method is provided so as to be arranged in three rows, and further, on a surface of the folded portion 5 of the heat shrinkable film 2 which contacts the heat shrinkable film 2,
The heat-shrinkable packaging method is provided, wherein a hot-melt adhesive or a pressure-sensitive adhesive is applied, and the heat-shrinkable film 2 is a heat-shrinkable film having a gas barrier property. A heat shrink wrapping method is provided.

Hereinafter, the heat shrink wrapping method of the present invention will be specifically described. The heat-shrinkable packaging method according to the present invention provides the heat-shrinkable film 2 with the small holes 3 for air discharge, and one end of the heat-shrinkable film 2 so that the rows of the small holes 3 are completely closed. Is folded so that the folded portion 5 is located between the packaged object 1 and the heat-shrinkable film 2, the packaged object 1 is wrapped with the heat-shrinkable film 2, and the open portion including the folded crest is blown. Welding seals such as seals and overlapping seals,
The packaged object 1 is wrapped by a method such as an electrostatic seal, and is guided to a packaging machine provided with a heating means such as passing through a heat shrinkage tunnel or blowing hot air. This is a method of performing heat shrink wrapping with the heat shrinkable film 2. In this method, the folded portion of the heat-shrinkable film 2 and the open end of the other end are sealed by a fusing seal or the like, so that the folded portion 5 of the heat-shrinkable film 2 is Has the function of closing the column.

In the method of the present invention, the small holes 3 provided in the heat-shrinkable film 2 are preferably arranged in one row or two or three rows adjacent to each other, and more preferably, they are linearly approximated. preferable. If the small holes 3 are arranged in three or more adjacent rows, the width of the folded portion 5 of the heat-shrinkable film 2 that closes the small holes 3 needs to be widened, so that the appearance of the heat-shrinkable package deteriorates. It is also uneconomic. If the arrangement of the small holes 3 is far from being linear,
Since it is necessary to increase the width of the folded portion 5 of the heat-shrinkable film 2 that closes the small holes, the appearance of the heat-shrinkable package deteriorates and is uneconomical. The number and size of the small holes may be appropriately selected according to the degree of air discharge during heat shrinkage. Further, if the small holes 3 provided in the heat-shrinkable film 2 are perforated, the bag can be broken through the small holes when opening the heat-shrinkable package.

Furthermore, the surface of the folded portion 5 of the heat-shrinkable film 2 in the method of the present invention, which is in contact with the heat-shrinkable film 2, is heat-shrinked by heating at the time of heat-shrink packaging such as a hot-melt adhesive or an adhesive. When a coating agent that easily adheres to the water-soluble film 2 is applied, the small holes 3 are closed well, and excellent airtightness is obtained.

FIG. 1A is a perspective view showing one example of a heat-shrinkable package obtained by the method of the present invention. FIG. 1 (b)
FIG. 2 is a cross-sectional view taken along line AA of FIG. The packaged object 1 has the small holes 3 arranged in two rows, is covered by the folded portion 5 at one end of the heat-shrinkable film 2, and the opening portion is closed by the fusing seal 4. Heat shrink wrapped. The small holes 3 formed in the heat-shrinkable film 2 and arranged in two rows are covered with the folded portions 5 of the heat-shrinkable film 2. In addition, the folded portion 5 and the heat-shrinkable film 2 are blocked during the heat-shrink wrapping, and the airtightness is further improved.

The heat-shrinkable film 2 used in the present invention is a film that shrinks by heating, and is used for heat-shrinkable packaging such as a single-layer film of polypropylene, polyethylene, vinyl chloride or the like or a laminated film based on these resins. The film to be used is used. When a film having a gas barrier property is used as the heat-shrinkable film 2, it is possible to store a packaged object such as food for a long period of time. As the heat-shrinkable film having gas barrier properties, a single-layer film of polyamide, polyethylene terephthalate, polyvinylidene chloride or the like, or a multilayer in which a resin layer of polyvinylidene chloride or polyvinyl alcohol and another resin layer are laminated. Films and the like are preferred. The heat-shrinkable film 2 is preferably one that can be fused with a seal such as a fusing seal or a welding seal from the viewpoint of packaging workability. Are preferred.

The width of the folded portion 5 of the heat-shrinkable film 2 is preferably 2 cm to 10 cm.
If the film width is less than 2 cm, it is difficult to close the row of small holes, and if the film width exceeds 10 cm, the packaging finish will be unsightly.

[0016]

In the heat shrink wrapping method of the present invention, when heat shrinkage is performed by a heat shrink tunnel or the like, first, the air inside the package expands to expand only the heat shrinkable film, and the heat shrinkable film is folded. A gap is created between the portion and the film on the side provided with the small holes. In particular, in the case of fusing and sealing, the gap is stably present because the folded portion and the film on the side provided with the small holes are kept apart. Next, the heat-shrinkable film is shrunk while discharging the air inside the package from the arranged small holes to the outside. At this time, the internal pressure increases, but the gap still occurs because the inner surface of the folded portion on the side of the packaged object and the screen on the film side provided with the small holes are the same pressure. And as it shrinks, the folded part is pressed by the packaged object and closely adheres to the heat shrinkable film to close the small hole, and the packaging is completed by blocking, bonding, etc. between the folded part of the heat shrinkable film and the part provided with the small hole. I do.

[0017]

As described above, the heat shrink wrapping method of the present invention can be used to close small holes for air discharge during heat shrinkage.
Since the folded portion of the heat-shrinkable film is used, good airtightness is shown. For this reason, products that are easily affected by oxygen and moisture can be stored for a long period of time. In addition, since the small hole is covered with the folded portion, troubles such as breakage of the bag from the small hole during transportation or the like are reduced. In addition, since packaging can be easily performed at high speed, packaging cost can be reduced. Furthermore,
In the heat shrink wrapping method of the present invention, it is not necessary to use a strip film. Film positioning for closing the small holes is easy. The heat-shrinkable film does not meander even if the packaged object is long. The packaging machine can be made compact. And so on.

[Brief description of the drawings]

FIG. 1 (a) is a perspective view of a heat-shrinkable package obtained by a heat-shrinkable packaging method of the present invention. (B) is a sectional view taken along line AA of (a).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 packaged object 2 heat-shrinkable film 3 small hole 4 fusing seal 5 folded part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B65B 53/00-53/06 B65D 71/08

Claims (4)

(57) [Claims] In a heat-shrinkable packaging method for packaging an article to be packaged using a heat-shrinkable film, a small hole for discharging air is provided in the heat-shrinkable film so that the small hole is closed. Then, one end of the heat-shrinkable film 2 is turned back so that the folded portion 5 is located between the object to be packaged 1 and the heat-shrinkable film 2. A heat shrink wrapping method, comprising wrapping and then wrapping by sealing an open portion and then heating. 2. The heat-shrinkable packaging method according to claim 1, wherein the heat-shrinkable film 2 is provided with small holes 3 for air discharge arranged in one or two or three adjacent rows. 3. The heat-shrinkable packaging according to claim 1, wherein a hot-melt adhesive or a pressure-sensitive adhesive is applied to a surface of the folded portion 5 of the heat-shrinkable film 2 which contacts the heat-shrinkable film 2. Method. 4. The heat-shrinkable packaging method according to claim 1, wherein the heat-shrinkable film 2 is a heat-shrinkable film having gas barrier properties.