JPH04367456A - Heat shrinkable package - Google Patents

Abstract

PURPOSE:To obtain a heat shrinkable package having a good adhesion between the parts overlapped in an envelope like folding manner and suitable for a large or long sized article. CONSTITUTION:An article 5 is wrapped in the package wherein both the edges of a heat shrinkable film 1 are overlapped in an envelope like folding manner and a blocking accelerating agent 4 is applied between such joint faces and, in the course of passing through a heat shrinking tunnel, the package is heat shrunk and the parts 6 overlapped in the envelope like folding manner are closely attached together by the heat blocking.

Description

[Detailed description of the invention]

001

FIELD OF INDUSTRIAL APPLICATION The present invention is utilized for heat-shrink packaging one or more products using a heat-shrinkable film. In particular, it is effectively used for packaging large products and long products.

002]

BACKGROUND OF THE INVENTION Conventionally, heat-shrinkable packaging has been obtained by heat-sealing an object to be packaged and then heat-shrinking it. However, since this method requires a heat sealing step, there is a problem in that the packaging speed cannot be increased. As a solution to this problem, as described in Japanese Patent Application Laid-Open No. 2-258526, heat-shrinkable films are simply overlapped in an envelope-like manner and then passed through a heat-shrink tunnel. A method of obtaining a heat-shrinkable package by bonding the joined parts together by heat blocking (
Hereinafter, such a packaging method will be referred to as an overlap shrink packaging method. ) was found. The heat-shrinkable film used in this method is disclosed in Japanese Patent Application Laid-Open No. 2-269046.
It has been found that a multilayer heat-shrinkable film in which a polyethylene resin layer is laminated on the surface of a polypropylene resin layer, as described in the above publication, can be suitably used.

However, in the overlap shrink packaging method using such a multilayer heat-shrinkable film, heat blocking is weak, and furthermore, if the packaged item is large or long, it may be difficult to wrap it in an envelope-like manner. The overlapping part opens,
A good heat-shrinkable package could not be obtained. In addition, air bubbles were generated in the overlapping portion of the envelope pasting where thermal blocking occurred, resulting in an unsightly appearance.

004

[Problems to be Solved by the Invention] The present invention makes it possible to easily package large products and long products, etc., for which it is difficult to seal the overlapping portions of envelopes using the overlap shrink packaging method. Moreover, the present invention aims to provide a heat-shrinkable package with good appearance and no air bubbles in the overlapping portion of the envelope pasting.

005]

[Means for Solving the Problems] In order to solve the above-mentioned problems in a heat-shrinkable package produced by an overlap shrink packaging method, the present invention provides the following package. That is, the object to be packaged is placed inside a cylindrical body in which both edges of the heat-shrinkable film are overlapped in an envelope-like manner, and a blocking accelerator is continuously applied in the length direction between the overlaps. is accommodated, and the heat-shrinkable film is heat-shrinked during the process of passing through the heat-shrink tunnel, and the overlapped portions are tightly bonded together by heat blocking in an envelope-like manner.

[006] The contents of the present invention will be explained below with reference to the drawings. FIG. 1 is a perspective view showing a heat-shrinkable package of the present invention. The article to be packaged (5) is wrapped around the edge (2) of the heat-shrinkable film (1).
) and (3) are stacked one on top of the other in an envelope-like manner, and the blocking accelerator (4) is applied between the stacks, and housed in a package. The package is heat-shrinked, and the overlapped envelopes (6) are tightly bonded by heat blocking.

The heat-shrinkable film used in the present invention is not particularly limited, and films conventionally generally used for heat-shrinkable packaging can be used. for example,
Heat-shrinkable polyethylene films, polypropylene films, etc., polystyrene films, polyamide films, polyester films, etc. can be used. Moreover, these multilayer products can also be used as appropriate.

The blocking accelerator used in the present invention is not particularly limited, but part coating agents that have been conventionally used to impart heat-sealability can be used. For example, chlorinated polyethylene, chlorinated polypropylene, heat seal varnish, etc. are preferably used.

[009] The method of applying the blocking accelerator is not particularly limited, but conventional methods can be used. For example, it can be carried out by an extrusion coating method, a roll method, a spray method, or the like. The blocking accelerator must be applied continuously in the length direction between the films in the overlapped area of the envelope in order to cover the packaged item. It is. For example, the above conditions can be satisfied by coating the entire surface of one side of the film, but it is preferable to apply the coating between the stacked envelopes and not to other parts. preferable. If the blocking accelerator is applied in areas other than between the stacked envelopes, the transparency of the film may decrease or the film and the packaged item may adhere to each other, which is undesirable. FIG. 2 is a schematic diagram showing the application form of the blocking accelerator between stacked envelopes. In the above case, the width over which the blocking accelerator is applied may be appropriately determined depending on the size, shape, etc. of the object to be packaged. For example, if the object to be packaged is large or long, it is preferable to apply the blocking accelerator over a wide range.

[010] When the surface to which the blocking accelerator is applied is present other than between the stacked envelopes, it is preferable that the package is packaged so that the surface to which the blocking accelerator is applied is located on the inner surface of the package. This tendency is particularly strong when the blocking accelerator is applied to the entire surface of one side. In other words, if the surface to which the blocking accelerator is applied is located on the outer surface of the package, if the heated package inside the heat shrink tunnel or immediately after exiting the heat shrink tunnel is rubbed against guide rolls, belt conveyors, etc. The surface of the applied blocking accelerator may be roughened, and the transparency and gloss of the heat-shrinkable package may be reduced.

[011] The width of the overlapping envelope stickers may be appropriately determined depending on the size and shape of the object to be packaged, that is, the length of the overlapping portion of the envelope stickers. For example, if the item to be packaged is large or long and the length of the overlapped portion is long, it is preferable to widen the width of the overlapped envelopes.

The heat-shrinkable package of the present invention can be obtained by the following steps. First, when both edges of the heat-shrinkable film are overlapped in an envelope-like manner, one side of the heat-shrinkable film is placed so that the area where the blocking accelerator is applied is at a position that satisfies the conditions of the present invention. Apply blocking accelerator. After forming a cylindrical body by overlapping both edges of the heat-shrinkable film obtained in this manner in an envelope-like manner using a former, an object to be packaged is housed in the cylindrical body, and the object to be packaged is Both ends are sealed or cut to obtain a package before heat shrinkage. The package is placed on a conveyor so that the overlapping portion of the envelope pasted form is on the lower side, and passed through a heat shrink tunnel to be heat-shrinked and heat-blocked between the overlapping envelope pasted forms to obtain a heat-shrinkable package. . In addition, when both ends of the packaged item are melt-sealed, the packaged item is completely sealed, but if it is only cut and not heat-sealed, both ends of the packaged item are sealed. is in an open state. However, even in this state, both ends of the packaged object are sufficiently held by the shrinkage of the heat-shrinkable film.

013]

[Function] The heat-shrinkable package obtained by the overlap shrink-wrapping method of the present invention has a blocking accelerator applied between the films in the overlapping portion of envelope pasting, so that it can be wrapped in the heat-shrinkable tunnel at an early stage. Moreover, the heat blocking strength is strong and good adhesion is exhibited. Therefore, a good heat-shrinkable package can be obtained even when the packaged item is large or long and the package has a long overlapped envelope-like part. In other words, in the case of a package with a long overlapping part of envelope pasting, when the air inside the package expands during heat shrinkage and the package expands, the force applied to the overlapping part of envelope pasting increases, and the overlapping part becomes easy to come off. However, in the heat-shrinkable packaging of the present invention, thermal blocking occurs early during heat-shrinking, and when the packaging is inflated, they are already in close contact, so the overlapped envelope-like parts do not come off. . Therefore, the resulting heat-shrinkable package does not have poor adhesion in the overlapped envelope-like parts, and the heat-shrinkable package of the present invention has a blocking promoter between the films of the overlapped envelope-like parts. Because it is coated, it does not create bubbles when heat blocking occurs. This results in a neat packaging finish.

[014] Hereinafter, the content of the present invention will be explained in more detail by showing Examples and Comparative Examples of the present invention, but the present invention is not limited thereto.

[Example 1] First, chlorinated polyethylene was applied to a width of 30 mm on one edge of a multilayer heat-shrinkable film in which both outer layers were made of polyethylene resin and the core layer was made of polypropylene resin. Next, a cylindrical body is formed by overlapping both edges of the film in a 50 mm envelope-like manner, and the floor pillar is vertically housed in the cylindrical body, and a heat-shrinkable package of the floor pillar is formed by an overlap shrink wrapping method. I got it. In addition, in the stacking of envelopes, the edge of the film coated with chlorinated polyethylene is positioned on the outside of the cylindrical body, and the chlorinated polyethylene is applied between the films of the overlapped part of the envelopes. The membrane was placed in place. Further, both ends of the package were not heat-sealed but simply cut and heat-shrinked in the unsealed state. As a result, the obtained heat-shrinkable packaging did not come off when stacked, and the long envelope-like overlapping parts all showed good adhesion, and these parts did not contain any air bubbles and had good adhesion. It had a nice packaging finish.

015]

[Comparative Example 1] The multilayer heat-shrinkable film used in Example 1 was not coated with chlorinated polyethylene as in Example 1,
Other than that, a heat-shrinkable package for a floor pillar was obtained in the same manner as in Example 1. As a result, in the heat-shrinkable package obtained, there was a portion where the overlap of about 300 mm was removed approximately at the center of the overlapping portion of the envelope pasting, and the adhesion was poor in other areas as well. Furthermore, air bubbles were present in the overlapping portion of the envelope pasting, which was unsightly.

016]

Effects of the Invention: The heat-shrinkable packaging of the present invention can be packaged at high speed and at low cost, and has good adhesion at the overlapped portion of envelopes, and furthermore, does not contain air bubbles in the overlapped portion. This makes it ideal for packaging products. In particular, it is suitably used in the packaging of long products such as large products and precious wood, since the overlapped portions of envelopes do not come off and exhibit good adhesion.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a heat-shrinkable package of the present invention.

FIG. 2 is a schematic view showing the application form of a blocking accelerator at the overlapping portion of envelope pasting.

[Explanation of symbols]

1 Heat shrinkable film 2 Heat shrinkable film edge 3 Heat shrinkable film edge 4 Blocking accelerator 5. Items to be packaged 6　Envelope sticker overlapping part

Claims (4)

[Claims] [Claim 1] Edge (2) of heat-shrinkable film (1)
and (3) are superimposed on each other in an envelope-like manner, and a blocking accelerator (4) is continuously applied in the length direction between the superpositions, and the packaged object (
5) is accommodated, the heat-shrinkable film is heat-shrinked during the process of passing through a heat-shrink tunnel, and the overlapping portion (6) is tightly adhered by heat blocking in an envelope-like manner. 2. The heat-shrinkable package according to claim 1, wherein the object to be packaged (5) is a large or long object. 3. The heat-shrinkable package according to claim 1, wherein the blocking accelerator (4) is applied only between the overlapped envelope parts (6). 4. The heat-shrinkable package according to claim 1, wherein the blocking accelerator (4) is chlorinated polyethylene or chlorinated polypropylene.