JPS6042115B2 - Shrink film removal method on container surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting off a cylindrical shrink film (heat-shrinkable synthetic resin film) that has been torn on the surface of a container.

Shrink films are often adhered to the surfaces of packaging containers such as glass bottles and injection molded plastic containers, either as a product mark (label) or as a container protective film.

Of course, this film has trademarks, plants, etc. printed on its surface as required, is made into a cylindrical body, is fitted into a container, and is tightly adhered to the outer circumferential surface of the container by the heat shrinkage force of hot air, etc. This is what I did. After the container is used once, it is generally collected and used again as a packaging container.

However, the shrink film on the surface of the container often has minute scratches or stains on its surface during the previous distribution and use process, and its function as a label and protective film is impaired, so it is difficult to reuse it. In some cases, it is necessary to remove the old film and reapply a new film to refresh the exterior. Conventionally, as a method for removing this film, a method has been exclusively used in which the film is cut by pressing a cutter such as a cutter knife against the surface of the container.

But... However, this method is cumbersome, difficult to automate, and has low efficiency. In addition, a coating is applied directly above the container surface (inside the film) to prevent the bottle from breaking or causing scratches. The synthetic resin coating is damaged by knives, so repair work is needed. The drawback is that it takes a long time to process and, in some cases, the coating has to be removed and a new coat applied. Therefore, the actual situation is that the container recycling process is complicated, inefficient, and requires a large amount of cost. The present invention has been made in view of the above, and provides a novel film cutting method that utilizes a high-pressure water jet as a means for removing a cylindrical shrink film applied to the surface of a container by heat shrink treatment.

That is, the present invention injects a high-pressure water jet and applies the high pressure of the jet to a cylindrical shrink film (hereinafter also simply referred to as "film") to locally concentrate tensile stress. The film is cut linearly from one end to the other end, making it possible to efficiently and continuously remove the film without damaging the coating of the container. The present invention will be explained in detail below.

FIG. 1 is a side explanatory view showing a specific example of the film cutting procedure according to the method of the present invention, and FIG. 2 is a plan explanatory view, in which 1 is a container (glass bottle), 2 is a shrink film attached to the container, and 3 is a high pressure water injection nozzle.

The container 1 is placed and fixed on a suitable transfer means 4 such as a conveyor, and is adapted to move at a predetermined speed along its axial direction (arrow X). Note that instead of moving the container 1, the nozzle 3 may be moved relative to the container. The present invention
A high-pressure water jet is sent from the nozzle 3 to one end 2 of the film 2.
.

1 to form a film 2 and a container surface 1.

A high-pressure water jet is inserted between the film 2 and the film 2, and the high pressure of the inserted high-pressure water jet is applied locally to the film 2 (hereinafter, that part is referred to as the "point of action of the jet").
By moving the container, its point of action is moved to one end 2 of the film.

1 to the other end 2.2, the film 2 is torn linearly in the axial direction of the container, as shown in FIG.

As shown in FIG. 4, the breaking mechanism is that the jet 5 inserts the film 2 between the film 2 and the container surface 1.1 due to its high pressure, and the inserted high-pressure water 5.1 causes the film to break.
A sudden local concentration of tensile stress occurs in the circumferential direction (arrows Yl and Y2 in FIG. 4), causing the film to instantly break. In this way, a high-pressure water jet connects the film 2 and the container surface 1.

1. Start the operation of breaking the film by inserting it between the two ends of the film and using the tensile stress generated in the film, and then move the high-pressure water jet in the axial direction of the container to break the film at the other end. By doing this, the film 2 is cut almost linearly over the entire length in the axial direction, and as the cylindrical shape opens, the film 2 loses its heat shrinkage force (clamping force) to the container. Leave the container as is.

When implementing the method of the present invention, the pressure of the high-pressure water jet and the angle formed by the jet with the container surface at the point of application (spray angle)
(θ), nozzle diameter, cutting speed (moving speed of the point of action),
The cutting conditions such as the distance between the nozzle nozzle and the point of application (spraying distance) are appropriately set according to the strength of the film and the like.

For example, the jet discharge pressure is 50-100k91cI
t, injection angle (0) 15-300 nozzle diameter 0.5-1
．． 57077! , injection distance 60~A1 cutting speed 1
It can be 0 to 60Tf01t/sec. Note that if the movement of the container is stopped in the middle of the cutting operation, the coating will often be damaged even if the jet pressure is relatively low. As mentioned above, the method of the present invention uses a high-pressure water jet to locally concentrate stress on the film and break the film. If it rises above the surface of the container, stress will be dispersed and it will be difficult to break it.

In such a case, it is preferable to abut press members for pressing the film against the container surface on both sides of the portion of the film to be cut. FIG. 5 shows an example in which a pair of rod-shaped bodies 6, 6'' are pressed against both sides of the part to be cut as presser members. In this way, the film 2 on both sides of the point of action of the jet 5 is removed from the container surface. There is no floating, and the jet's high pressure can be locally concentrated for smooth cutting.
FIG. 6 shows an example in which a roll 12 having a pair of annular bodies 7, 7'' is used as a presser member.The roll is moved in the tearing direction in accordance with the tearing speed of the film, and the same as above is used. Effects can be obtained.Roll 12 as a pressing member
In addition, as shown in FIG. 7, a ring-shaped body 7,7'' is supported at an appropriate distance from the shaft 10, or as shown in FIG. 14 to form a pair of annular bodies 7, 7''.
Note that the ring-shaped bodies 7, 7'' of each roll are disk bodies (for example,
It may be made of metal, plastic, wood, etc.) with an outer layer member 9 made of rubber or the like attached to the outer peripheral surface of the material 8. In order to cut the film using a high-pressure water jet at a higher speed and more efficiently, it is preferable to use a cutter together with the above-mentioned pressing means.

An example is shown in FIG. This uses a cutter-equipped roll 15 in which a disk-shaped cutter 11 is attached coaxially between the ring-shaped bodies 7 and 7'' of the rolls shown in FIG. 7, and the ring-shaped body functions as a pressing means. At the same time, the film 2 stretched out by the jet comes into contact with the cutting edge of the cutter 11, allowing for rapid tearing.The cutter may have a circular cutting edge as shown in the figure.
Alternatively, as shown in FIG. 10, a cutter 1" having a saw-blade-shaped cutting edge may be used. In particular, when using a cutter 11" having a saw-blade-shaped cutting edge, it may be rotatably attached to the roll shaft 10. Since the jet rotates against each cutting edge, the cutter can cut effectively. Of course,
The diameter of the cutting edge of the cutter is slightly smaller than the diameter of the annular body 7, 7'' so as not to damage the coating on the container surface.
The cutting edge must not come into contact with the container surface. In addition, although normal temperature water may be used as the high-pressure water jet, heated water may also be used.

When heated water is used, the heat causes the film to undergo thermal contraction, creating a shrinkage force that tends to firmly adhere to the container surface, so that the high pressure of the jet effectively acts on the film. If the contraction force is sufficient, the use of the pressing member can be omitted. In addition, if an appropriate organic solvent that has a film dissolving effect is added to high-pressure water, the high pressure of the jet and the dissolving effect of the solvent will be mutually added.
The film cutting efficiency can be further improved. Note that a hot air jet can also be used instead of the high-pressure water jet. In this case as well, the film is thermally shrunk by the hot air jet, and the high pressure of the jet allows the cutting blade to work effectively. In particular, if the temperature of the hot air is increased (eg, 240 to 400°C), the film will melt, and the cutting efficiency will be further increased. Next, the method of the present invention will be specifically explained with reference to Examples.

EXAMPLE The film on the surface of a glass bottle was cut off as shown in FIG. 1 above.

The excision conditions are shown in Table 1. In addition, the bottle size is
The mouth diameter is approximately 20 mm, the maximum diameter is approximately 80 Tgftφ, and the length is approximately 400 Tr$L.The film is uniaxially stretched heat-shrinkable polyvinyl chloride (with surface printing), thickness is approximately 40 μ, and length is approximately 84 mm. The shrinkage rate is approximately 50%. Moreover, the injection distance of the jet is approximately 75 wurL. As a result of each of the above tests, the film was removed smoothly and the coating was not damaged.

As described above, according to the present invention, when recycling containers, the adhered film can be continuously and efficiently removed without causing any damage to the coating on the container surface, and the process can be easily mechanized and automated. , processing efficiency can be significantly increased compared to conventional methods.

[Brief explanation of the drawing]

FIG. 1 is a side explanatory view illustrating the implementation procedure of the method of the present invention;
Fig. 2 is an explanatory plan view, Fig. 3 is an explanatory plan view showing the film tearing situation, Fig. 4 is an explanatory cross-sectional view schematically showing the vicinity of the jet application point, Figs. 5, 6, and 7. , Figure 8, Figure 9
The figures are perspective explanatory views showing other cutting methods according to the present invention, and FIG. 10 is a side view explanatory view showing an example of a disk-shaped cutter. 1: Container, 2: Covering film, 3: Nozzle, 4: Container transfer device, 5: High pressure water jet, 6,6'', 12: Holding member, 11,1'': Disc-shaped cutter, 15: With cutter Presser foot roll.

Claims (1)

[Claims] 1. A high-pressure water jet is injected onto the surface of a container to which a cylindrical shrink film is attached, and the high-pressure water jet is inserted between the cylindrical shrink film and the surface of the container, and the insertion portion The operation of tearing the cylindrical shrink film due to the tensile stress generated in the cylindrical shrink film is started from one end side of the cylindrical shrink film, and while moving the high-pressure water jet relative to the container in the axial direction, the operation is performed to break the cylindrical shrink film from the other end side. 1. A shrink film cutting method for a container surface, which is characterized by cutting a cylindrical shrink film linearly over the entire length in the axial direction and opening the ring by gradually tearing the film until the cylindrical shrink film is opened. 2. Pressing parts for pressing the cylindrical shrink film against the container surface are placed on both sides of the part of the cylindrical shrink film adhered to the container surface to be broken, and a high-pressure water jet is applied to the container surface. A high-pressure water jet is inserted between the cylindrical shrink film between the pressing parts and the container surface, and the cylindrical shrink film directly below is pressed against the container surface by the pressing member against the high-pressure water caused by the insertion. While pressing down, the operation of tearing the cylindrical shrink film due to the tensile stress generated in the cylindrical shrink film by inserting the high-pressure water jet is started from one end side of the cylindrical shrink film, and the high-pressure water jet is inserted into the container. A shrink film on the surface of a container, characterized in that the cylindrical shrink film is linearly broken and opened over the entire length in the axial direction by gradually breaking the film to the other end while relatively moving in the axial direction. Excision method. 3. The shrink film cutting method according to item 2 above, wherein the pressing member is a pair of rod-shaped bodies. 4. The shrink film cutting method according to item 2 above, wherein the pressing member is a roll having a pair of annular bodies. 5. A pair of ring-shaped bodies located at the part of the cylindrical shrink film attached to the container surface that is to be cut and pressed on both sides thereof, and a ring-shaped body provided between the ring-shaped bodies that does not touch the container surface. A cutter roll equipped with a disk-shaped cutter having an outer diameter is brought into contact with the container surface from the top surface of the cylindrical shrink film, and a high-pressure water jet is ejected onto the container surface to cut the cylinder between the pair of ring-shaped bodies. A high-pressure water jet is inserted between the cylindrical shrink film and the container surface, and the cylindrical shrink film immediately below is pressed against the container surface by a pair of annular bodies against the high pressure caused by the insertion, while the high-pressure water jet is inserted. The operation of tearing the cylindrical shrink film by causing the cylindrical shrink film to protrude from the container surface between a pair of annular bodies and bringing it into contact with the cutting edge of a disc-shaped cutter in the presence of tensile stress is performed. By starting from one end of the cylindrical shrink film and gradually tearing it to the other end while following the high-pressure water jet and moving the roll with the cutter relative to the container in its axial direction, the cylindrical shrink film is cut. A method for cutting shrink film from the surface of a container, which is characterized by cutting the shrink film linearly over the entire length in the axial direction and opening the shrink film.