JP3224811B2 - Sleeve packaging method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic sleeve packaging method using a heat-shrinkable film having a larger heat-shrinkage amount in a horizontal direction than in a vertical direction. In particular, the present invention exhibits excellent characteristics in a collecting sleeve package which is widely used as a collecting package for canned beer, juice and the like.

[Prior Art] In a conventional sleeve packaging method, an object to be packaged is inserted into a tubular body which is made of a heat-shrinkable film having a larger heat shrinkage amount in a lateral direction than in a longitudinal direction, and is cut at both ends. ,
Alternatively, a method is used in which a package is inserted into a continuous tubular body of the heat-shrinkable film, and then both ends of the package are cut, and the heat-shrinkable film is thermally shrunk in a heat-shrink tunnel. Have been. However, in this method, unless the film is an expensive uniaxial heat-shrinkable vinyl chloride resin film, wrinkles are formed around the sleeve package as shown in FIG. 3 or as shown in FIG. As described above, the tubular film is drawn to the center of the package, and the exposed portions at both ends of the package increase. As a result, in addition to the vinyl chloride resin film having a uniaxial heat shrinkability, a heat shrinkable film having a larger heat shrinkage in the horizontal direction than in the vertical direction, for example, using a heat shrinkable film made of polyethylene, polypropylene, or the like. However, when the collecting sleeve is packaged, the objects to be packaged at both ends protrude from the package, so that the function as the package is not fulfilled.

Japanese Patent Publication No. Sho 56-12533 discloses that a wrapping film provided with a perforation for separation, which is cut in the width direction at regular intervals in the length direction, is formed into a cylindrical shape continuous in the length direction. Then, the article is wrapped between the perforated portions, and the tubular film in which the article is encapsulated is heated and shrunk in an unconstrained state, and the film is shrunk by the convergent tension of the perforated portion between the articles due to the shrinkage of the film. Shrink wrapping method characterized in that the perforated portion is self-cut during heating, and the heating of the film is terminated when the cut end comes into close contact with the article. Was. That is, in the case of using a heat-shrinkable film in which the perforated portion is hard to be cut in the heat-shrinkable tunnel, the shrinkage of the heat-shrinkable film causes the packages inserted through the perforated portion to be attracted to each other. The to-be-packaged body was continuously connected in the cylindrical body, and favorable sleeve packaging was not obtained. In addition, if the perforation holes are enlarged or the distance between the holes is reduced in order to facilitate cutting in the heat shrink tunnel, the film is likely to be cut in the packaging process before entering the heat shrink tunnel. Machine suitability was getting worse.

The heat-shrinkable film in which the perforated portion is hard to be cut in the heat-shrinkable tunnel is a film having a strong tensile strength or tear propagation strength, a film having a weak heat-shrinkage stress, or the like at a heating temperature in the heat-shrinkable tunnel. I say In particular, this tendency is strong in a heat-shrinkable laminated film in which the low-temperature heat-shrinkability is improved in order to improve the finish of shrink-wrapping, and in a heat-shrinkable laminated film in which the mechanical strength is improved.

[Problems to be Solved by the Invention] The present invention facilitates the cutting of a perforated portion in a heat shrink tunnel in a sleeve packaging method described in the above-mentioned Japanese Patent Publication No. 56-12533, and the suitability of the packaging machine is improved. An object of the present invention is to provide a sleeve packaging method which is excellent and has excellent shrink wrapping finish.

In particular, the method of the present invention is a heat-shrinkable film in which the perforations are hardly cut in the heat-shrink tunnel, for example,
A heat-shrinkable laminated film composed of two types of polyethylene resin layers, and a heat-shrinkable laminated film composed of a polyethylene-based resin layer and a polypropylene-based resin layer, more specifically,
Heat shrinkable laminated films such as linear low density polyethylene / low density polyethylene / linear low density polyethylene, linear low density polyethylene / polypropylene / linear low density polyethylene, polypropylene / ultra low density polyethylene / polypropylene The purpose of this method is to obtain a sleeve package having a good packaging finish.

[Means for Solving the Problems] The present invention employs the following means to solve the above problems. That is, a heat-shrinkable film provided with separation perforations intermittent in the width direction at regular intervals in the length direction is formed in a tubular body continuous in the length direction, and the packaged object is interposed between the perforation portions. After inserting the package, the heat-shrinkable film of the tubular body into which the package is inserted is heat-shrinked in the heat-shrink tunnel, and the perforations between the packages are self-cut by the heat-shrinkage stress. In a sleeve packaging method in which a film is brought into close contact with the periphery of an object to be packaged and the film cut portion is heat-shrinked so as to be in close contact with the object to be packaged, the heat shrinkability of a tubular body into which the object to be packaged is inserted Before the film is guided into the shrink tunnel, hot air is blown on the perforated portion to cut off a part of the perforated portion, and the heat shrinkable film is eaten on the shoulder of the packaged object. Written to, it is intended to be causing caught. Then, the hot air blown to the perforation portion is substantially uniform in the circumferential direction of the heat-shrinkable film formed in the cylindrical body, or almost symmetrically on the left and right sides of the cylindrical body, or on the upper and lower sides. Preferably, it is sprayed substantially symmetrically. Furthermore, it is preferable that the hot air blown to the perforation portion is not blown to the portion where the packaged object is inserted, but is blown only to the portion where the perforation processing is performed.

 Hereinafter, an embodiment of the present invention will be described with reference to FIG.

The heat-shrinkable film 1 is sent to the former 2 to be formed into a tubular shape, and both edges of the film are heat-sealed by the heat sealing device 3. At this time, the film is subjected to perforations 5 at regular intervals by a perforator 4 which moves back and forth in synchronization with the film feed speed in the process of feeding the film to the former 2. Former 2
The packaged object 9 is sequentially inserted into the tubular film 6 formed at a constant interval and between the perforations by a packaged object insertion attachment 8 attached to the packaged material supply conveyor 7.

Thereafter, the tubular film including the packaged object is continuously pulled out of the former by a pair of drawer conveyors 10. At this time, a part of the perforation portion is cut 12 (see FIG. 1) by blowing hot air from hot air generators 11 (note, only one of the hot air generators is shown in FIG. 1) attached to the left and right sides of the cylindrical body. Note that a part of the perforation is cut off on both left and right sides of the cylindrical body.
In the figure, only one cut portion is displayed. ) Occurs, and the heat-shrinkable film bites into the shoulder of the packaged object, causing the package to be caught. Then, the tubular film partially cut off from the perforation section rides on the transfer conveyor roll 13 and is kept in an unconstrained state in a heat shrink tunnel.
It is fed into 14 and heated. Note that the state in which the heat-shrinkable film bites into the shoulder of the packaged object and is caught means the state as shown in FIG.

The tubular film heated in the heat shrink tunnel is completely cut from the perforated portion by its own heat shrinkage stress, and the cut film end 15 is stretched along each end of the package by heat shrinkage. Be adhered.

In the case where the hot air blown to the perforation portion is provided only on one side of the tubular body and a partial cut of the perforation occurs only on one side of the tubular body, the partial cut occurs in the heat shrink tunnel. The heat-shrinkable film on the side where the heat-shrinkable film is subjected to heat shrinkage in a state of no load, as a result, the heat-shrinkage stress applied to the uncut perforated portion is weakened, and cutting may be difficult. Also, a difference occurs in the bundling force applied to the packaged body between the side where partial cutting has occurred and the side where it has not been cut, and this causes not only wrinkles in the obtained packaged body, but also in the case of integrated packaging In some cases, the arrangement of the packaged objects is disturbed, and it is difficult to obtain a good sleeve package. Therefore, in order to always obtain good sleeve packaging,
It is necessary to prevent partial cutting of perforations from occurring only on one side of the tubular body. For that purpose, the hot air blown to the perforation portion is blown almost uniformly in the circumferential direction of the cylindrical body, or almost symmetrically on both the left and right sides of the cylindrical body, or almost symmetrically on both the upper and lower sides. It is preferable to do so.

In addition, it is preferable that the hot air blown to the perforated portion is not blown to the portion where the packaged object is inserted, from the viewpoint of shrink-wrapping finish. That is, the portion to which the hot air is blown has a lower heat shrinkage, and a difference in the heat shrinkage from the other portion. Then, a portion having a low heat shrinkage is forcibly shrunk to a surrounding portion having a high heat shrinkage at the time of heat shrink wrapping. In addition, the part to which the hot air is blown exerts a kind of heat treatment effect, and the heat shrinkage stress as a whole is weakened, so that the tightness and the binding power of the package may be inferior. As a method of blowing hot air only to the perforation section, the hot air generator is moved in synchronization with the drawer or the hot air is instantaneously blown when the perforation section passes in front of the hot air generator. There is a method of spraying.

When the entire perforation portion is cut by the hot air blown to the perforation portion, wrinkles are formed around the sleeve package as shown in FIG. 3 or, as shown in FIG. The film of the body is drawn to the center, and the exposed portions at both ends of the packaged body become large.

[Operation] In the present invention, since a part of the perforation portion is already cut before being guided into the heat shrink tunnel, complete cutting of the perforation portion in the heat shrink tunnel can be easily performed. In addition, since the heat-shrinkable film bites into the shoulder of the packaged body and is caught, the stress at the time of the heat shrinkage is easily applied to the perforated portion, and as a result, self-cutting is likely to occur.

Further, in the heat shrink tunnel, the heat shrinkable film bites into the shoulder of the object to be packaged and is caught, so that sufficient shrinkage stress is applied to the central portion of the object to be packaged, resulting in a sleeve package having excellent tightness. . In addition, the cut end of the film is not drawn to the center of the package, but adheres to the end of the package, so that the film is sufficiently wrapped up to both ends of the package.

[Effects of the Invention] The present invention can be easily cut in a heat shrink tunnel without performing perforation processing with a large hole or a narrow gap between holes, so that packaging before entering the heat shrink tunnel is performed. The sleeve can be easily packaged without any film cutting during the process. In addition, although it is excellent in various properties such as low-temperature shrinkability, it can be easily sleeve-wrapped even using a heat-shrinkable film having difficulty in cutting a film in a heat-shrink tunnel. The properties of these heat-shrinkable films can be fully exhibited.

Further, the sleeve package obtained by the method of the present invention,
There are no wrinkles around and the display effect is excellent. In addition, since both ends of the package are in close contact with each other, not only a good finish is exhibited, but also an excellent effect of holding the goods at both ends is obtained in an integrated sleeve package such as canned beer.

[Brief description of the drawings]

FIG. 1 is a side view showing an example of an apparatus for performing the method of the present invention. FIG. 2 shows a state in which the heat-shrinkable film bites into the shoulder of the packaged object and is caught.
FIG. 3 shows a sleeve package having wrinkles around it, and FIG. 4 shows a sleeve package in which both ends are exposed more. DESCRIPTION OF SYMBOLS 1 ... Heat-shrinkable film, 2 ... Former, 3 ... Heat-sealing device, 4 ... Perforator, 5 ... Perforation, 6 ... Cylindrical film, 7 ... Conveyor to be packaged, 8 ... … Packaged object insertion attachment,
9: Packaged object, 10: Drawer conveyor, 11: Hot air generator, 12: Partial cut of perforation part, 13
…… Transfer conveyor roll, 14 …… Heat shrink tunnel, 15
…… cut film edge

Claims (4)

(57) [Claims] 1. A heat-shrinkable film provided with a separating perforation intermittently interrupted in the width direction at regular intervals in the length direction is formed in a cylindrical body continuous in the length direction, and is interposed between the perforation portions. After inserting the package, the heat-shrinkable film of the tubular body into which the package is inserted is heat-shrinked in the heat-shrink tunnel, and the perforations between the packages are self-cut by the heat shrinkage stress. At the same time, the film is closely attached to the periphery of the packaged object, and
In a sleeve packaging method in which the film cut portion is heat-shrinked so as to be in close contact with the object to be packaged, before the heat-shrinkable film of the tubular body into which the object to be packaged is inserted is guided into the shrink tunnel, the perforation portion is formed. A method of wrapping a sleeve, wherein hot air is blown on the perforated portion to cut a part of the perforated portion, and at the same time, the heat-shrinkable film is cut into the shoulder of the packaged object to generate a hook. 2. The sleeve packaging method according to claim 1, wherein the hot air blown to the perforation portion is blown substantially uniformly around the circumference of the cylindrical body. 3. The method according to claim 1, wherein the hot air blown to the perforation portion is blown substantially symmetrically on both left and right sides of the cylindrical body, or substantially symmetrically on both upper and lower sides. Sleeve packaging method. 4. The sleeve packaging method according to claim 1, wherein the hot air blown to the perforation portion is blown only to the perforated portion.