JPS587545B2 - Heat shrink packaging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat-shrinkable packaging method, which eliminates distortion of the printed portion after packaging when tightly packaging an object using a heat-shrinkable film that has been appropriately printed. ,
It is an object of the present invention to provide a packaging method that gives a beautiful appearance as if a printed part is located at a predetermined location on an object to be packaged.

At present, it is well known as heat-shrink packaging to pre-pack the part to be packaged with a heat-shrinkable film, heat-shrink it, and package it tightly.

This packaging method produces very beautiful packaged products, but if it is possible to print on the heat-shrinkable film and place a beautiful pattern in a predetermined location on the packaged product, the product value will be comparable to that of conventional products. It is thought that this will result in a significant improvement.

However, in the conventional heat-shrink packaging method, even if the heat-shrinkable film is beautifully and finely printed, the printed pattern will be distorted and shrunk due to heat shrinkage, and the printed pattern will be distorted on the packaged item. It does not stay in place and the packaged product becomes unsightly.

Possible causes of this include variations in the heat shrinkage rate depending on the direction or location of the heat-shrinkable film, the position of the packaged object within the heat-shrinkable film bag during prepackaging, and the shape of the packaged object.

For these reasons, it has not been possible to print beautiful fine prints on the film portion of heat-shrinkable packaging products.

For example, when storing food in a cup-shaped container such as a cup-shaped instant ramen and wrapping it in heat shrink packaging, the product name,
The design, contents, cooking method, manufacturer's name, etc. are printed on a heat-shrinkable film and pre-wrapped so that it is placed on top of the lid of the container.If heat-shrink packaging is performed, the printed pattern will be distorted and the text will not be readable. I can't.

Furthermore, it is difficult to position the printed pattern at a predetermined location, and some or all of the printed pattern may move to another location.

Also, in many cases it is not possible to print these directly on the lid of the container.

This is because the surface of the lid is uneven to improve its strength, making the printed pattern unsightly.
It becomes difficult to read small characters.

For this reason, at present, these are printed on paper and placed on the lid of the container for heat shrink packaging, and only simple printing is done on the heat shrink film.

In this method, packaging costs are increased due to the extra effort of printing on paper and the effort of inserting the paper into a heat-shrinkable package.

If these types of printing are applied to heat-shrinkable film, and the printed pattern does not become distorted even after packaging, and if the printed pattern is located on the top of the container lid, packaging costs can be kept low, and moreover, beautiful packaged products can be obtained. It will be done.

The present inventors have completed the present invention as a result of intensive research to compensate for the deficiencies of the prior art.

That is, the heat-shrink packaging method of the present invention will be explained with reference to an illustrated example. When heat-shrink wrapping an object 2 with a printed heat-shrinkable film 1 (FIG. 1),
The entire surface or most of the printed areas 3, 4.5 of the heat-shrinkable film 1, or the peripheral area of the printed area (however, the peripheral area also includes the ends of the printed area).

(hereinafter referred to as peripheral portion) 6 is fixed to a predetermined position of the packaged object 2 by an appropriate means, and further heat-shrinked using a heating means such as a heating tunnel, so that the packaged object 2 is tightly attached as shown in FIG. It is to be packaged.

In the illustrated example, the packaged object 2 is a cup instant noodle container 7 sealed with a lid 8.

An annular groove 8C is formed in the lid 8 for the purpose of improving strength, and divides the surface of the lid 8 into an inner part 8a and an outer part 8b.

In the illustrated example, if the printed parts 3, 4, 5 themselves are to be fixed on the lid 8, they are glued onto the inner part 8a, and the peripheral part 6 of the printed parts 3, 4.5 is fixed on the lid 8. If you want to fix it to
This can be glued onto the outer part 8b.

Furthermore, in the illustrated example, printing is performed on the heat-shrinkable film 1 so that the printed portions 3, 4.5 are located on the lid 8 of the packaged item 2; 2 container 7
It may be made corresponding to the side or bottom surface of the.

When fixing the printed portions 3, 4, 5 or their peripheral portions 6 onto the packaged item 2, it is sufficient to fix the printed portions 3, 4, 5 or their peripheral portions 6 over the entire surface, but In the present invention, as the heat-shrinkable film, films conventionally used in heat-shrink packaging can be used.

For example, heat-shrinkable films such as polyethylene, polypropylene, and polyvinyl chloride are most suitable.

Furthermore, printing on the heat-shrinkable film is performed in a size that is approximately the same as the size of the printed pattern that is planned after the packaged object is packaged.

With the current development of printing technology, it has become possible to produce beautiful, fine prints using gravure printing, flexographic printing, etc., and these conventional techniques can easily produce beautiful, fine prints.

Pre-wrapping is carried out using a heat-shrinkable film with the above printing, which is thicker than the item to be packaged, similar to the conventional heat-shrink wrapping method.
Thereafter, the printed portion of the shrinkable foam or its surrounding area is fixed to a predetermined location on the packaged object.

Alternatively, after fixing the printed portion of the heat-shrinkable film or its peripheral portion to a predetermined position on the object to be packaged, pre-wrapping is performed to make the film thicker than the object to be packaged.

At this time, the fixing method includes, for example, fixing with an adhesive or heat sealing.

In the case of fixing with an adhesive, any commonly used adhesive can be used as long as the heat-shrinkable film and the item to be packaged are fixed together.

Preferably, a fast-acting adhesive or a high tack adhesive that can withstand the heat shrinking force of the heat shrink film in a heat shrink tunnel is suitable.

Alternatively, an adhesive that is fixed only during heat shrinkage may be used.

Examples of the adhesive used in the present invention include resin adhesives such as vinyl acetate resin, ethylene vinyl acetate resin, vinyl chloride resin, acrylic resin, polyamide resin, and polyvinyl alcohol resin, or chloroprene rubber, nitrile rubber, SBR, Examples include rubber adhesives such as natural rubber and butyl rubber, and natural adhesives such as starch, glue, and gelatin.

For food packaging, etc., it is preferable to choose solvent-free or water-soluble types from the above-mentioned types, and it is preferable to select appropriately depending on the purpose.

As a method for applying the adhesive, conventional methods such as brush coating, roll coating, and spray coating can be used.

If using a rewetting adhesive, apply water or solvent again just before fixing.

The coating can be applied to the heat-shrinkable film side, the packaged object side, or both.

In the case of fixation by heat sealing, it is necessary that the packaged item and the heat shrinkable film can be heat sealed.

Preferably, the packaged object is a thermoplastic resin or a thermoplastic resin coating.

As the heat sealing method, conventional methods such as hot plate sealing and impulse sealing can be used.

However, since it is a heat-shrinkable film, impulse sealing is more effective.

The prepackaged body, in which the printed portion of the heat-shrinkable film or its peripheral portion is fixed to a predetermined location of the packaged object, is heat-shrinked using a heat-shrink tunnel or the like in the same manner as in the conventional method.

In the method of the present invention, if the printed portions of the heat-shrinkable film themselves (numerals 3, 4, 5 in the figure) are adhered to the packaged item, the printed portions 3, 4, 4, No. 5 does not cause heat shrinkage and does not move from a predetermined location of the packaged object, while the parts other than the printed part shrink due to heat and form a close-fitting package.

Even if the peripheral part of the printed part of the heat-shrinkable film (number 6 in the figure) is stuck to the packaged item, the printed part 3, 4.5 will be free of wrinkles during the heat-shrinking process. There is almost no heat shrinkage at the level of tension, and the printed pattern etc. will not be distorted.

Not only that, but wrinkles and the like are eliminated and the printed pattern becomes more beautiful because it is in a state of tension.

Further, since the peripheral portion 6 of the printed pattern etc. is fixed to a predetermined location on the packaged item 2, it will not move to another location.

As explained above, the present invention eliminates the conventional defects by a novel method and can be used for heat shrink packaging of many items to be packaged.

Furthermore, like the conventional heat shrinking method, it is easy to put into practical use, and moreover, it significantly reduces packaging costs.

This will be explained below using examples.

Example 1 General instant ramen cup (body: Styrofoam, lid: polystyrene with filler mixed in, height 65
An SBR adhesive was applied to a width of 5 mm along the periphery of the upper part of the lid with a bottom diameter of 90 mm and a lid of 170 mm.

Thereafter, a 15 μm thick heat-shrinkable polypropylene film printed in six colors was covered so that the entire upper surface of the lid of the cup was covered with a printed pattern, and the cup was fixed so that the printed portion was located on the upper portion of the lid.

After that, a cut-seal machine is used to make a bag thicker than the cup (
The bag was made into a bag (260 mm x 260 mm).

The obtained prepackaged body was passed through a heating tunnel having a length of 2 m and a temperature of 160° C. for 5 seconds.

As a result, the resulting close-contact packaging for instant cup noodles has a brilliantly printed pattern on the top of the cup lid, and the printed pattern is not distorted and even the smallest letters can be clearly read, making it beautiful. Met.

Example 2 Household detergent bottle (made of low density polyethylene, capacity 215
The bottle (400 im x 280 mm) was prepackaged with a 40 μ thick heat-shrinkable polyethylene film that was printed in 4 colors so that a printed pattern was applied to the side surface of the bottle (0CC).

Thereafter, the printed portion was placed on the side of the bottle, and the peripheral portion of the printed pattern was fixed using an impulse sealer.

The obtained prepackaged body was passed through a heating tunnel having a length of In and a temperature of 180° C. for 3 seconds.

As in Example 1, the resulting close-tight package of household detergent bottles had a beautiful printed pattern that was clearly positioned in the designated place, and that there was no distortion in the printed pattern and that even the smallest letters could be clearly read. It was something.

Example 3 A polyvinyl alcohol-based rewetting adhesive was preliminarily applied along the periphery of the top of the lid of an instant ramen cup similar to Example 1 in a 5-width area.

A heat-shrinkable polypropylene film similar to that used in the example was used to cover the entire top of the lid with a printed pattern, and immediately before fixing the film and the top of the lid, water was applied to the adhesive using a roll. Then I fixed it.

Thereafter, preliminary packaging and heat shrinkage were performed in the same manner as in Example 1.

The resulting close-contact package of instant cup noodles was as beautiful as in Example 1.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of an embodiment of the method of the present invention, and FIG. 2 is a perspective view of a finished product produced by the method of the present invention. 1... Heat shrinkable film, 2... Item to be packaged, 3, 4, 5... Printed part, 6...
・Around the printed part.

Claims (1)

[Claims] 1. When heat-shrink wrapping an object 2 using a heat-shrinkable film 1 having printed portions 3, 4.5, prior to heat-shrinking the heat-shrinkable film 1 on which the object 2 has been pre-wrapped. A heat shrink packaging method characterized in that the printed portions 3, 4.5 or their peripheral portions 6 are fixed onto the article to be packaged 2 by appropriate means such as adhesion with an adhesive or heat welding.