JPH0620896B2 - Collective packaging method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a collective packaging method for collecting a plurality of rectangular parallelepiped unit packaging bodies and packaging them in a batch.

For example, taking a piece of printed paper as an example, after printing, it is cut into unit paper pieces, and each piece of 2000 pieces is packaged into one piece. Furthermore, one piece of this package is arranged in contact with two rows of five pieces and arranged in a collective package. Then, one tier of the 20,000-pack aggregate package is stacked on the pallet in multiple stages and moved together with the pallet. One unit package consisting of 2000 pieces of this paper is currently packaged in a high-pressure polyethylene film. It is said that it is packaged in polyethylene film not only because it is readily available and cheap, but because of its suitable gas permeability, it is suitable for breathing freshly printed paper strips. Thus, there are many cases where several pieces of paper are unit-wrapped, and they are further group-wrapped, and the unit-wrapping material is very often a normal high-pressure polyethylene film.

[Problems to be solved by the invention]

When collecting a plurality of rectangular parallelepiped unit package bodies that are packaged with the ordinary high-pressure polyethylene film as described above and packaging them, make sure that the package body after collective packaging does not bend or lose its shape. The cage should be convenient to handle. For that purpose, it is desirable to heat seal the four circumferences of the collective packaging film, and then heat shrink it to perform tight packaging. However, when the same high-pressure polyethylene film is used for the collective packaging film, there is a problem that the unit packaging film and the collective packaging film are fused during such heat shrinkage. Further, when a plurality of unit packages are assembled and simply placed on a belt and moved, the individual packages are likely to be displaced, the shrinkage finish is not good, and heat sealing for four rounds is difficult to perform. In addition, if the four-round heat seal is performed during continuous movement, it is difficult to heat seal because the object to be packaged is misaligned, and it becomes impossible to seal at extreme times, and if it is continuously moved, the problem will be compounded. Had. In addition, it is not only laborious to separate each collective package after sealing, but the separation line of the seal is not always straight, and it is difficult to reliably separate the bottom seal and the next top seal. there were.

It is an object of the present invention to provide an improved method for assembling and packaging rectangular parallelepiped unit packages packaged with a conventional high-pressure polyethylene film as described above.

[Means for solving problems]

That is, the present invention is a method of collecting and packaging a plurality of rectangular parallelepiped unit package bodies packaged with polyethylene film, in which a plurality of unit package bodies are densely assembled and the tip of the packaged package body (1). Is a biaxially stretched crosslinked polyethylene film having an ORS of 50 g / mm ² or more and a gel fraction of 20 to 50% in the vicinity of the portion, and at least two upper and lower continuous films with holes provided in the upper film ( 4) and (4 ') are provided with a top seal portion sealing the tip portion, and the upper and lower two films (4) and (4') are placed with the package to be assembled (1) facing the top seal portion. And the moving belts (5) and (5 ') while sandwiching the moving belts (5) and (5') to move in the pushing direction to cover the to-be-collected package (1) with the films (4) and (4 '), and the rear end thereof. When the part passes through the heat sealer (6) consisting of two adjacent sealers, the movement is stopped and the seal film (4), (4 ′) Is heat-sealed, cut at the middle part of both heat-seals, and bisected into the front and rear sealing parts, the front part is the bottom seal of the main package to be assembled, and the rear part is the top seal of the next package to be assembled. And nothing,
Next, place it between the side sealers (8) while pinching it between the moving belts (7) and (7 '), and stop it, and side seal with a heat sealer (8) equipped with a holding plate for four rounds. Complete the heat seal, then move it to 130
The present invention relates to a collective packaging method, which comprises shrink-wrapping a collective packaging film, which has been sealed on four circumferences, in a heating atmosphere of up to 160 ° C.

The present invention will be specifically described below.

The film for collective packaging used in the present invention is a biaxially stretched crosslinked polyethylene film. Examples of the polyethylene film polymer include ethylene homopolymers and ethylene-vinyl acetate copolymers. The stretching degree of this film is the contraction stress (ORS, ASTM D15
(According to 04) of 50 g / mm ² or more is preferable because it is easy to achieve the object of the present invention. If the ORS is less than 50 g / mm ² , the film will be insufficiently stretched due to insufficient shrinkage. The degree of cross-linking needs to be 20 to 50%, preferably 30 to 40% in terms of gel fraction. If it is less than 20%, it tends to be fused with the packaging film of the unit package, and if it exceeds 50%, the sealing property deteriorates. The thickness is required to be strong enough to make the collective package solid and is 20 to 100 μm (μ), preferably 30 to 60 μm.

The heat seal temperature of the film is about 180 ° C. The tunnel temperature for causing heat shrinkage is selected from the temperature range of 130 to 160 ° C, preferably 140 to 150 ° C. The heating time should not be too long for the efficiency of the operation, and about 15 seconds is practical.

Taking an example of a piece of printed paper, the size of one unit package is 75 × 160 × 100 (mm), and the assembled packages arranged in two rows for five are 320 × 385 × 100 (mm). . As shown in the schematic side view of the automatic wrapping apparatus in FIG. 1, the to-be-collected wrapping body 1 of this size is placed on the belt conveyor 2 and advanced. A unit package is a roll of rolls 4 and 4'for gathering and wrapping a biaxially stretched crosslinked film with a thickness of 50μ on top and bottom, and the ends of the rolls 4 and 4'from both rolls are heat-sealed (top seal). It is placed in front of the body 1 and the moving belts 5 and 5 ′ for moving the unit packaging body 1 between the top and bottom are rotated. At this time, the upper film is provided with a plurality of needle holes by the roll 3 with needles. A heat sealer 6 is provided in front of the moving belts 5 and 5 ', and when the rear end portion of the package to be assembled is positioned on this sealer 6, the moving belts 5 and 5'stop and are perpendicular to the traveling direction. The bottom seal and the top seal are performed by pressing the film on the side, and at the same time, the gap between these two seal portions is cut. Here, the bottom seal and the top seal (next minute) are completed. Then the upper and lower moving belts 7,
The side sealer 8 shown in FIG.
The movable belts 7 and 7'are stopped when the package to be assembled is positioned during the period (not shown in FIG. 1), and both side seals are performed by the hot plate 82 while pressing the film with the film pressing plate 81. Thus, the package to be assembled, which has been subjected to the four-round heat sealing, is then transferred to the hot air tunnel 9 heated to 130 to 160 ° C. In the tunnel 9, rotatable roller rods 10 are lined up, on which the package to be assembled moves. With such a device, heat sealing and heat shrink wrapping of the collective packaging film of the package to be assembled are automatically performed. The movement stop operation is performed by a photoelectric tube detection method.

At this time, the heat sealing temperature can be 180 ° C.
When the heating temperature of the film is 15 seconds, the tunnel temperature for shrinking the film exceeds 160 ° C, and the film punctures. On the other hand, when the temperature is lower than 130 ° C., the shrinkage of the film is insufficient and the film for collective packaging is weak and insufficient. It is preferable this shrinkage stress of the film is 50 g / mm ² or more, although in the case of 55 g / mm ² could be performed without any trouble, 30 g / mm ²
In the case of No. 4, even if the degree of crosslinking of the film was within the specified range, fusion between the ordinary non-crosslinked polyethylene film of the unit package and the crosslinked polyethylene film for collective packaging occurred. The following table shows the shrinkage stress (ORS) of the film for collective packaging, the tunnel temperature, and the quality of collective packaging.

[Effects of the Invention] In the method of the present invention, collective packaging is performed intermittently, so that heat sealing can be reliably performed and the finish is good, and even if troubles in the process occur, repair is easy to perform. Further, since the belts are squeezed and moved between the belts, there is almost no misalignment between the individual unit packages in the collective package, sealing is easy, and the finish of the shrink wrapping is sure. In addition, since the side sealer is provided with a holding plate for sealing, the side seal is reliable and the packaging finish is excellent.Since the bottom seal and the top seal of the continuous film are pressed and cut at the same time, the collective package can be reliably separated. is there. In addition, since the upper film is provided with holes, it generally has a function of bulging on the top when heat shrinks, and the internal air is surely and quickly released so that the finish of shrink wrapping is excellent. Is.

[Brief description of drawings]

FIG. 1 is a schematic side view of an automatic collective packaging device. Second
The figure is a side sealer sectional view. 1 ... Collected package 2 ... Belt conveyor 3 ... Roll with needle 4, 4 '... Film for collective packaging 5, 5' ... Moving belt conveyor 6 ... Heat sealer 7, 7 '... Moving belt Conveyor 8 …… Side heat sealer 81 …… Presser plate 82 …… Hot plate 9 …… Hot air tunnel 10 …… Roller rod

Claims (1)

[Claims] 1. A method of collecting a plurality of rectangular parallelepiped unit packages packaged with polyethylene film and collectively packaging the same, wherein a plurality of unit packages are densely assembled.
A biaxially stretched crosslinked polyethylene film having an ORS of 50 g / mm ² or more and a degree of crosslinking of 20 to 50% in gel fraction near the tip of (1). A top seal part, which seals the leading end of the continuous films (4) and (4 ′), is arranged, and the upper and lower two films (4) and (4), with the collected package (1) facing the top seal part, 4 '), and while squeezing between the moving belts (5) and (5'),
The package to be assembled (1) is moved in the pushing direction to be covered with the films (4) and (4 ′), and is moved when the rear end passes through a heat sealer (6) consisting of two adjacent sealers. Stop and heat seal the seal films (4) and (4 '), cut at the middle part of the both heat seals and divide into two front and rear seal parts, and the front part is the bottom seal of the package to be assembled, The rear part is used as the top seal for the next package to be assembled, and then it is placed between the side sealers (8) while being pinched between the moving belts (7) and (7 ') and stopped, and the holding plate is pressed. Side seal with a heat sealer (8) equipped with to complete heat seal for 4 laps, then move it to 130 ~ 1
A collective packaging method comprising shrinking and shrink-wrapping a collective packaging film that has been sealed on four sides in a heating atmosphere of 60 ° C.