JP2009012355A - Bag making method of shrink label or roll label - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the flotation of the label end of the joined part of a plastic film label to enhance the aesthetic properties of the joined part, to eliminate the troublesomeness of the control related to the use of an adhesive and to reduce the occurrence of molding defectiveness such as the waving of the joined part or the like when the label is subsequently subjected to thermal shrinkage. <P>SOLUTION: After both ends 2a and 2b of a film 1 for a shrink label or a film for a roll label are superposed one upon another so as to form the joined part 3, a laser beam 9 is thrown on the joined part while traversing the boundary 6 of the region 4 of the joined part and the region 5, where both ends of the film are not superposed one upon another, adjacent to the region of the joined part to thermally weld the mutually superposed ends of the film along the scanning locus 7 of the laser beam and the irradiation with the laser beam is repeated while positionally shifted along the direction 8 of the joined part to thermally weld the joined part to form the film into a bag. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a cylindrical label that is externally fitted to a container such as a beverage or food, and in particular, when both ends of a raw film are thermally fused with a laser beam to form a bag into a cylindrical shape. The present invention relates to a technique for improving the cosmetics of a seam that is a part.

  Shrink labels that are printed on the original film of a packaging material, cut into a predetermined width, and bonded to each other using an adhesive or solvent to form a cylindrical shape have an upper and lower base that are not yet It is wound up in the form of a long tubular body that has been cut and supplied to a beverage filling factory as a wound product. Then, the wound product is cut into individual shrink labels by a shrink labeler in the filling line so that an upper base and a lower base are formed at a predetermined pitch. Immediately after that, it is fitted into the container, and is heat-shrinked by being heated by heating means such as hot air blowing, and is mounted on the outer surface of the container.

  In addition, for the purpose of reducing the cost of shrink labels, both ends of a label made of shrink film are not bonded together. A shrink film, that is, a roll label, is used which is wound in a roll shape in which the portions are bonded to each other using an adhesive or a solvent. In general, the roll label is not thermally shrunk.

  In addition, for the purpose of reducing the cost of shrink labels, both ends of the printed label material, which is not bonded to both ends of the shrink film, is wrapped around the outer surface of the container in the labeler. The labeler (Roll-on-Shrink-on labeler, hereinafter referred to as “Roll-on”) was bonded to each other using a heat-sensitive adhesive and a UV curable resin, and then thermally contracted by heating. "On-Shrink-on label") has been developed.

  In recent years, a laser welding technique has been developed in which both ends are bonded together by thermal fusion using a laser beam instead of bonding them together using an adhesive or a solvent (see, for example, Patent Document 1 or 2).

JP 2002-248687 A JP 2000-141469 A

  However, the shrink label, roll label, and roll-on-shrink-on label are in a state where the label edge floats at the joint when the two end portions are overlapped and bonded together. There was a problem with sex. Further, in the shrink label and the Roll-on-Shrink-on label, when the label is subsequently heat-shrinked, the seam may not be shrunk to a desired shape.

  In addition, a method using an adhesive is used to bond resin films, but there are many points that are difficult to manage and maintain such as management of adhesive, management of curing time, maintenance of injection parts of adhesive, etc. .

  Therefore, the present invention relates to shrink label, roll label, or Roll-on-Shrink-on label, which prevents the label edge from floating, improves the cosmetic appearance of the label seam, and uses an adhesive. The purpose is to eliminate the troublesome management. Furthermore, in the shrink label and Roll-on-Shrink-on label, when the label is subsequently heat-shrinked, it reduces the occurrence of molding defects such as undulations at the seam, and improves the cosmetics of the seam of the label. For the purpose. In the present invention, hereinafter, the “Roll-on-Shrink-on label” is a concept included in the “shrink label”.

  The present inventors solve the above-mentioned problem by irradiating a laser beam so as to straddle the label edge of the joint, and scanning so as to repeat the straddling while gradually shifting along the direction of the joint. The present invention was completed. That is, the shrink label or roll label bag-making method according to the present invention includes a shrink label film or a roll label film that is overlapped on both ends of the film with a seam, and then aligned with the seam area. The laser beam is irradiated while crossing the boundary with the region where the film is not overlapped next to the eye region, and the overlapped films are thermally fused along the scanning trajectory of the laser beam, and the laser beam irradiation is performed as described above. The film is formed by heat-sealing the seam by repeatedly performing the process while shifting the position along the direction of the seam.

  The shrink label or roll label bag making method according to the present invention includes a form in which the scanning trajectory of the laser beam is a zigzag shape, a curved wave shape, a square wave shape, a rectangular wave shape, a trapezoidal wave shape, or a false stitch shape. . The scanning shape is appropriately selected according to the label design, its shape, or the shape of the joint.

  In the shrink label or roll label bag manufacturing method according to the present invention, the laser beam is oscillated from a semiconductor laser, a YAG laser, or a fiber laser, and an absorbent that absorbs the laser beam is applied or kneaded into a film. It is preferable to keep it. Laser beams emitted from these laser oscillators are not easily absorbed by plastic films such as OPP film, OPE film, OPS film, PLA film, PET / OPS film, or PET film, which are the base materials for shrink labels or roll labels. It is difficult to heat-seal. Then, a desired location can be heat-seal | fused by previously apply | coating or knead | mixing the absorber which absorbs a laser beam to a film.

  In the shrink label or roll label bag-making method according to the present invention, the film is formed of a resin having a transmittance at a wavelength of 10600 nm of 50% or less in terms of a film thickness of 50 μm, and the laser beam is oscillated from a carbon dioxide laser. And it is preferable to irradiate the said laser beam from the diagonal direction with respect to the normal line direction of a film surface toward the location where the films in the said joint contact | connect from the end surface side of the said film. A laser beam oscillated from a carbon dioxide laser is easily absorbed by a plastic film that serves as a base substrate for a shrink label or a roll label. For this reason, before the location where the films in the seam are in contact with each other is melted, the surface irradiated with the laser beam is melted first, and a hole is opened. However, by irradiating from the direction oblique to the normal direction of the film surface, it is possible to irradiate the laser beam mainly to the place where the films are in contact with each other, so that the films are heat-sealed without opening a hole. Can do. At this time, since the laser beam is irradiated while crossing the boundary, it is not necessary to perform advanced control such as accurately irradiating only the end surface of the label end of the joint. Furthermore, since it is not necessary to apply or knead the absorbent to the film, it is possible to eliminate the step of applying or kneading the absorbent.

  In the bag manufacturing method of the shrink label or roll label according to the present invention, any form of performing the above-mentioned process in-line in which the contents are filled in the container or off-line is included.

  The present invention can prevent the label edge from floating on the shrink label, roll label, or Roll-on-Shrink-on label, and can enhance the cosmetic appearance of the label. Furthermore, in the shrink label and Roll-on-Shrink-on label, when the label is subsequently heat-shrinked, it reduces the occurrence of molding defects such as undulations at the seam, and improves the cosmetics of the seam of the label. Can do. Further, since the laser welding method is used for joining the seams, there is no troublesome management related to the use of the adhesive and management of aging after bonding.

  Embodiments of the present invention will be described with reference to the accompanying drawings. The embodiment described below is an example of the configuration of the present invention, and the present invention is not limited to the following embodiment.

  The embodiment will be described with reference to FIGS. FIG. 1 is a view showing an example of a locus of a laser beam when making a shrink label or roll label according to the present embodiment, (a) is a schematic view seen from the joint direction, and (b) is A- It is a partial expanded sectional view of A '. As shown in FIG. 1, in the shrink label or roll label bag-making method according to this embodiment, first, both ends 2 a and 2 b of a film 1 for a shrink label or a film 1 for a roll label are provided with a joint 3. Overlapping. Next, a laser beam 9 is irradiated while crossing the boundary 6 between the region 4 of the joint 3 and the region 5 where the film 1 adjacent to the region 4 of the joint 3 is not overlaid, Heat fusion is performed along the scanning locus 7, and further, the laser beam 9 is repeatedly irradiated while shifting the position along the direction 8 of the joint 3. The displacement of the position is preferably set at a predetermined constant interval. By performing such an operation, the seam 3 is heat-sealed to form the film 1. In FIG. 1, the irradiation direction of the laser beam 9 is substantially parallel to the normal direction of the film surface. Hereinafter, the steps will be described.

  First, the both ends 2a and 2b of the film for shrink labels or the film 1 for roll labels are overlapped with the joint 3 provided. The film for shrink labels and the film for roll labels are both heat-shrinkable films having self-shrink properties, such as OPP films, OPE films, OPS films, PLA films, PET / OPS films, or PET films. For example, a film having a thickness of 45 to 60 μm is frequently used. The two ends 2a and 2b of the film 1 are overlapped with a joint 3 provided.

  Here, the film 1 is supplied from an original film which is a long film take-up product, but it should be a film take-up product which has been cut in advance in the direction parallel to the long direction to adjust the film size. Is preferred. And both ends 2a and 2b of the film 1 are the case of the both ends of the elongate width direction of the film winding product in which the film size was adjusted, and the length of the film winding product in which the film size was adjusted There is a case where a scale-like film is cut in the width direction and the cut end portion.

  When both ends 2a, 2b of the film 1 are both ends in the width direction of the long shape, first, after making a bag, it is cut and a label is formed. On the other hand, when both ends 2a and 2b of the film 1 are cut ends, a seam is bonded after cutting, so that a label is formed when bonded. Further, in order to enhance the adhesion of the seam 3 when the seam 3 is provided and stacked, the film 1 is preferably in a state of being wound around a cylindrical part in any case. In addition, the width | variety of the area | region 4 of the joint 3 is 3-15 mm, for example.

  Next, the laser beam 9 is irradiated while crossing the boundary 6 between the region 4 of the joint 3 and the region 5 where the film 1 adjacent to the region 4 of the joint 3 is not overlapped. As shown in FIG. 1B, heat irradiation can be performed without leaving the overlapped films 1 up to the end 2b of the label by crossing the boundary 6 with the irradiation of the laser beam 9. At this time, heat fusion is performed along the scanning locus 7 of the laser beam 9.

  Then, as shown in FIG. 1A, the region 4 of the joint 3 and the region of the joint 3 are scanned by zigzag scanning with the irradiation of the laser beam 9 along the direction 8 of the joint 3. The laser beam 9 is repeatedly irradiated across the boundary 6 with the region 5 where the film 1 adjacent to 4 is not overlapped. By scanning in a zigzag manner, the position of the locus 7 is shifted at a predetermined constant interval. The width of one cycle of the zigzag shape is, for example, 2 mm or less.

  In the shrink label or roll label bag making method according to the present embodiment shown in FIG. 1A, the scanning locus 7 of the laser beam 9 is zigzag-shaped, but as another form, the locus 7 is shown in FIG. It is also possible to use a curved wave shape such as a sine wave shown in FIG. Alternatively, the locus 7 may be a square wave shape, a rectangular wave shape, a trapezoidal wave shape, or a lace stitch shape shown in FIGS. 2A and 2B are schematic views as seen from the seam direction showing an example of the scanning trajectory of the laser beam, where FIG. 2A is a sine wave shape, FIG. 2B is a square wave shape, FIG. 2C is a rectangular wave shape, and FIG. A wave shape, (e) shows a stitch shape. Furthermore, it is good also as deformed shapes, such as the shape which combined these shapes for every fixed period, and the shape which combined and added the height component.

  Here, in order to increase the tensile strength in the direction orthogonal to the direction 8 of the joint 3, it is preferable to provide a locus that is parallel or nearly parallel to the direction 8 of the joint and to increase the ratio of the locus. For example, a square wave shape or a rectangular wave shape.

  As shown in FIG. 1 (a), heat fusion work is performed along the seam direction 8 from the upper bottom end of the seam 3 of the film wound in a cylindrical shape toward the lower bottom end. Go ahead. It is preferable to perform heat fusion from the end portion on the upper bottom side to the end portion on the lower bottom side, and the film can be prevented from floating at the end portion.

  If the product is wound into a cylindrical shape with the longitudinal direction as the axis before cutting the wound product with the film wound into a long shape, the film is continuously wound into a cylindrical shape with a certain pause. Therefore, the concept of the upper or lower cylindrical side is considered as follows. That is, the top side in the film feeding direction is the upper bottom side, and the subsequent side is the lower bottom side. That is, the heat fusion work is advanced along the film feeding direction. By performing the above operation, the seam 3 is heat-sealed to produce the film 1 in a bag.

  When the type of laser beam used in the bag manufacturing method of the shrink label or roll label according to this embodiment is a light beam oscillated from a semiconductor laser, YAG laser or fiber laser, it becomes a base substrate for the shrink label or roll label. Since light of that wavelength is hardly absorbed by a plastic film such as an OPP film, an OPE film, an OPS film, a PLA film, a PET / OPS film, or a PET film, it is difficult to heat-seal. Therefore, it is preferable that an absorbent that absorbs the laser beam 9 is applied to the seam 3 before being applied or kneaded into the film. The absorbent may be either a dye-based absorbent or a pigment-based absorbent. When the absorbent is kneaded into the film, the absorbent is mixed with the resin, and the mixed material may be formed into a sheet. When applying the absorbent, the desired location can be heat-sealed by adjusting the location. In FIG. 1 (a), an absorbent is applied to one or both of the two overlapping surfaces of the film, and heat-sealed by irradiation with a laser beam to form a heat-sealed portion 10. The films 1 are joined together. The irradiation of the laser beam 9 is not limited as long as the applied absorbent is irradiated. For example, the irradiation is performed in a direction parallel to the normal direction of the surface of the film 1 or is inclined with respect to the normal direction. Also good.

  When the type of the laser beam used in the bag manufacturing method of the shrink label or roll label according to the present embodiment is a light beam oscillated from a carbon dioxide laser, from the end surface side 2b of the film 1 as shown in FIG. It is preferable to irradiate the laser beam 9 from the oblique direction with respect to the normal direction of the film surface toward the position where the films 1 in FIG. FIG. 3 is a diagram showing an example of a locus of a carbon dioxide laser beam when making a shrink label or roll label according to the present embodiment, (a) is a schematic view seen from the joint direction, and (b) is a diagram. It is a partial expanded sectional view of AA '. Film that is a base material for shrink labels or roll labels, and is formed of a resin whose transmittance at 10600 nm, which is the oscillation wavelength of a carbon dioxide laser, is 50% or less in terms of film thickness of 50 μm, such as PLA film, PET / OPS film, or PET A plastic film such as a film is difficult to heat-seal because the laser beam 9 is easily absorbed. When the laser beam 9 is absorbed, the surface of the film 1 on the irradiation side of the laser beam 9 is melted first and the hole is opened before the portion of the joint 3 where the films 1 are in contact with each other is melted. This is because it becomes. However, as shown in FIG. 3B, by irradiating the laser beam 9 from an oblique direction with respect to the normal direction of the film surface (an angle formed between the normal direction of the film surface and the oblique direction is expressed as α), A portion where the films 1 are in contact with each other can be heat-sealed to form the heat-sealing portion 10. The angle α formed by the oblique direction with respect to the normal direction of the film surface is, for example, 15 to 75 °, preferably 30 to 60 °. At this time, even if the laser beam 9 is irradiated from an oblique direction, the laser beam 9 can be irradiated while crossing the boundary 6 as shown in FIG. Therefore, it is not necessary to perform advanced control such that only the end surface of the label end 2b of the joint 3 is irradiated with the laser beam 9 with high accuracy. Furthermore, since it is not necessary to apply or knead the absorbent to the film by using a carbon dioxide laser, it is possible to eliminate the step of applying or kneading the absorbent.

  Even in the case of using a carbon dioxide laser, the transmittance of the OPP film, OPE film, and OPS film is 50% or more, so that melting on the form surface does not occur, so the normal direction of the film From the above, that is, heat fusion is easily performed by irradiation from directly above. At this time, it is not necessary to perform the step of applying or kneading the absorbent.

  The shrink label or roll label bag-making method according to the present invention can be applied in any form of performing the above-mentioned process in-line, in which the contents are filled in the container, or off-line. When performing in-line, the film feeding operation is repeated by temporarily stopping the feeding of the long film in accordance with the timing of the filling process into the contents container, and then feeding the film. It is preferable to scan the irradiation of the laser beam when the feeding is temporarily stopped. On the other hand, even when performing in-line, when continuously feeding a long film without pausing temporarily or when continuously feeding a long film offline, It is preferable to scan the irradiation of the laser beam shown in FIGS. 1 to 3 in consideration of the film feed rate so as to cancel the film feed rate relatively.

It is a figure which shows an example of the locus | trajectory of the laser beam at the time of bag-making of the shrink label or roll label concerning this embodiment, (a) is the schematic seen from joint direction, (b) is the part of AA ' It is an expanded sectional view. It is the schematic seen from the seam direction which shows the form of the scanning locus of the laser beam in this embodiment, (a) is a sine wave shape, (b) is a square wave shape, (c) is a rectangular wave shape, (d) is Trapezoidal wave shape, (e) shows a sewed shape. It is a figure which shows an example of the locus | trajectory of the carbon dioxide laser beam at the time of bag-making of the shrink label or roll label concerning this embodiment, (a) is the schematic seen from the seam direction, (b) is AA '. FIG.

Explanation of symbols

1 Film for shrink label or film 2a, 2b for roll label 3 Both ends of film 3 Joint area 4 Seam area 5 Area where film next to seam area is not overlapped 6 Seam area and seam Boundary with the region where the film adjacent to the region is not overlapped 7 Laser beam scanning trajectory 8 Direction of joint 9 Laser beam 10 Thermal fusion part

Claims (5)

  After overlapping both ends of the film for shrink label or the film for roll label with a seam, the boundary between the seam area and the area where the film adjacent to the seam area is not overlapped By irradiating a laser beam while traversing, and thermally fusing the stacked films along the scanning trajectory of the laser beam, repeatedly performing the irradiation of the laser beam while shifting the position along the direction of the joint, A method for making a shrink label or a roll label, wherein the film is made by heat-sealing a seam.   2. The shrink label or roll label bag making according to claim 1, wherein the trajectory of the scanning of the laser beam is a zigzag shape, a curved wave shape, a square wave shape, a rectangular wave shape, a trapezoidal wave shape, or a lace stitch shape. Method.   The laser beam is oscillated from a semiconductor laser, a YAG laser, or a fiber laser, and an absorbent that absorbs the laser beam is applied or kneaded into a film at the joint. Bag making method for shrink labels or roll labels.   The film is formed of a resin whose transmittance at a wavelength of 10600 nm is 50% or less in terms of a film thickness of 50 μm, the laser beam is oscillated from a carbon dioxide gas laser, and the film at the joint from the end face side of the film The shrink label or roll label bag-making method according to claim 1 or 2, wherein the laser beam is irradiated from an oblique direction with respect to a normal direction of the film surface toward a place where they are in contact with each other.   5. The shrink label or roll according to claim 1, 2, 3 or 4, wherein the step is performed in-line to fill the container with the contents or off-line. Label making method.

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