Method for manufacturing labeled container

Abstract

Provided is a method for manufacturing a labeled container that eliminates a need for refrigerated storage of a heat-shrinkable label and ensures a satisfactory finish of mounting a heat-shrinkable label.　The method for manufacturing a labeled container (50) includes: a step for preparing a roll product (10) of heat-shrinkable labels (1) having a widthwise heat shrinkage rate of 40% or more after immersing the heat-shrinkable labels (1) in a 90°C hot water bath for 10 seconds, and a widthwise natural shrinkage rate of 0.5% or less after storing the roll product (10) in a 55°C atmosphere for 7 days; a step for storing the roll product (10) in a 25°C to 55°C atmosphere for 24 hours or more; a step for having an automatic mounting machine (200) fit the heat-shrinkable labels (1) onto a container (4); and a step for causing the heat-shrinkable labels (1) adhere to an outer peripheral surface (40) of the container (4).

Description

Method for manufacturing a labeled container

[0001] The present disclosure relates to a method for manufacturing a labeled container.

[0002] For example, a heat-shrinkable film used for a heat-shrinkable label that is heat-shrunk and attached to the outer peripheral surface of a container such as a PET bottle for product display or the like hardly shrinks naturally at normal temperature and has heat-shrinkability such that it shrinks rapidly when heated to 60°C or higher.

[0003] While such a shrinkage rate is required, in seasons when the outside air temperature rises, the ambient temperature in a warehouse, the loading platform of a truck, etc. may rise to nearly 50°C, approaching the shrinkage start temperature of the heat-shrinkable film. Therefore, when storing a conventional heat-shrinkable film, it was necessary to keep the heat-shrinkable film refrigerated at 25°C or lower.

[0004] To solve such problems, for example, in Patent Document 1, even when stored in a warehouse other than one where temperature control is performed when the temperature is high in summer, the phenomenon that the heat-shrinkable film shrinks (so-called natural shrinkage) does not occur, the decrease in the shrinkage rate in the main shrinkage direction of the heat-shrinkable film is small, and it can be beautifully and efficiently attached without changing the temperature conditions for heat-shrinking when heat-shrinkably attaching to a container such as a PET bottle as a label. A heat-shrinkable polyester-based film is described.

[0005] WO2011 / 114934

[0006] In recent years, the methods for heat-shrinking heat-shrinkable labels have diversified. Therefore, there is a demand for a heat-shrinkable label that can cope with the diversification of heat-shrinking methods and has no problem in the finish.

[0007] In view of the above circumstances, an object of the present disclosure is to provide a method for manufacturing a labeled container that does not require cold storage of a heat-shrinkable label, can cope with the diversification of heat-shrinking methods, and has no problem in the attachability and finish of the heat-shrinkable label.

[0008] According to this disclosure, the process for preparing a roll of heat-shrinkable labels is as follows: the process for preparing a roll of heat-shrinkable labels is such that the heat shrinkage rate in the width direction after immersing the heat-shrinkable labels in a 90°C hot water bath for 10 seconds is 40% or more, and the natural shrinkage rate in the width direction of the heat-shrinkable labels after storing the roll in a 55°C atmosphere for 7 days is 0.5% or less; the process for storing the roll in a 25°C to 55°C atmosphere for 24 hours or more; and the process for setting the roll in an automatic loading machine, the automatic loading machine dispensing the heat-shrinkable labels from the roll and setting them to a predetermined size. A method for manufacturing a labeled container is provided, which includes the steps of: cutting the label into the specified shape, opening it, and then fitting the heat-shrinkable label into the container; and blowing hot air and / or steam onto the heat-shrinkable label fitted into the container to heat-shrink the label and make it adhere to the outer surface of the container, wherein the heat shrinkage rate of the heat-shrinkable label in the width direction after immersing the roll of heat-shrinkable label in a 90°C hot water bath for 10 seconds, after being stored for 24 hours or more in an atmosphere of 25°C to 55°C, is 40% or more.

[0009] According to this disclosure, it is possible to provide a method for manufacturing labeled containers that does not require refrigerated storage of heat-shrinkable labels and does not have problems with the application and finish of the heat-shrinkable labels.

[0010] This is a flow diagram of an example of a method for manufacturing a labeled container according to an embodiment. This is a schematic perspective view of an example of a roll of heat-shrinkable labels. This is a schematic perspective view of an example of a heat-shrinkable label. This is a schematic plan view of an example of a base film. This is a schematic side view of an example of an automatic loading machine. This is a schematic side view of another example of an automatic loading machine. This is a schematic side view of another example of an automatic loading machine. This is a schematic side view of another example of an automatic loading machine. This is a schematic perspective view illustrating an example of a container fitted with a heat-shrinkable label. This is a schematic cross-sectional view of an example along XI-XI in Figure 10. This is a schematic plan view of an example of a labeled container. This is a schematic side view of an example of a heating device. This is a schematic top view illustrating an example of the internal configuration of the heating unit shown in Figure 13. This is a schematic top view of another example of the internal configuration of the heating unit shown in Figure 13.

[0011] The embodiments will be described below. In the drawings used to describe the embodiments, the same reference numerals represent the same part or a corresponding part.

[0012] <Method for Manufacturing Labeled Containers> Figure 1 shows a flowchart of an example of a method for manufacturing a labeled container according to the embodiment. As shown in Figure 1, the method for manufacturing a labeled container according to the embodiment includes a step 102 of preparing a roll of heat-shrinkable labels, a step 103 of storing the roll for 24 hours or more, a step 104 of having an automatic mounting machine fit the heat-shrinkable labels onto the container, and a step 105 of making the heat-shrinkable labels adhere to the outer surface of the container.

[0013] <Process for preparing rolls of heat-shrinkable labels> Process 102 for preparing rolls of heat-shrinkable labels can be carried out by preparing a roll 10, for example, as shown in the schematic perspective view of Figure 2. The roll 10 of heat-shrinkable labels to be prepared, as shown in Figure 2, can be manufactured by flattening and winding a continuous body of heat-shrinkable labels 1, in which a single cylindrical heat-shrinkable label 1 is continuously connected in the direction along a virtual axis 2', as shown in the schematic perspective view of Figure 3.

[0014] <Heat Shrinkable Label> As shown in Figure 3, a single heat shrinkable label 1 has a longitudinal direction 2 which is the non-shrinking direction and a width direction 3 which is the main shrinking direction, and is processed into a cylindrical shape so as to surround a virtual axis 2' that extends along the longitudinal direction 2. In this specification, the non-shrinking direction (longitudinal direction 2) means a direction in which the shrinkage rate is smaller compared to the main shrinking direction (width direction 3), and does not necessarily mean that it does not shrink at all. The angle between the longitudinal direction 2 and the width direction 3 of the heat shrinkable label 1 is 90°. A cylindrical heat shrinkable label 1 can be obtained by folding a base film 11, for example, as shown in the schematic plan view of Figure 4, in the width direction 3 with the longitudinal direction 2 as the central axis and sealing both ends in the width direction 3.

[0015] Furthermore, the thermal shrinkage rate in the width direction of the heat-shrinkable label 1 after immersion in a 90°C hot water bath for 10 seconds is 40% or more, and the natural shrinkage rate in the width direction of the heat-shrinkable label 1 after storage of the roll of heat-shrinkable label 1 in a 55°C atmosphere for 7 days is 0.5% or less.

[0016] The thermal shrinkage rate in the width direction of the heat-shrinkable label 1 is calculated from the width of the heat-shrinkable label 1 before and after immersion in a hot water bath heated to 90°C for 10 seconds under no load, using the following formula (Equation A).

[0017] Widthwise heat shrinkage rate [%] = 100 × [{(Widthwise length of heat shrinkable label 1 before immersion) - (Widthwise length of heat shrinkable label 1 after immersion)} / (Widthwise length of heat shrinkable label 1 before immersion)] ... (Equation A)

[0018] The natural shrinkage rate in the width direction of the heat-shrinkable label 1 after storing the roll product 10 in a 55°C atmosphere for 7 days is calculated as follows: The roll product 10, which has been continuously stored in an atmosphere below 25°C, is then stored in a 55°C atmosphere (humidity 1% to 2%) for 7 days (hereinafter, "storing in a 55°C atmosphere (humidity 1% to 2%)" may simply be referred to as "aging"), and the width direction length of the heat-shrinkable label 1 before and after storage is calculated using the following formula (Equation B).

[0019] Natural shrinkage rate in the width direction [%] = 100 × [{(width direction length of heat shrinkable label 1 before aging) - (width direction length of heat shrinkable label 1 after aging)} / (width direction length of heat shrinkable label 1 before aging)] ... (Equation B)

[0020] Furthermore, from the viewpoint of obtaining a heat-shrinkable label 1 that prevents natural shrinkage and does not have problems with attachment even when attached to a container by heat shrinkage, it is preferable that the heat-shrinkable label 1 further satisfies the following requirements (1) and (2): (1) The thermal shrinkage rate in the width direction after immersion in a 60°C hot water bath for 10 seconds is 1% or less. (2) The thermal shrinkage rate in the width direction after immersion in a 70°C hot water bath for 10 seconds is 10% or less.

[0021] The thermal shrinkage rate in the width direction of the heat-shrinkable label 1 in a 60°C or 70°C hot water bath can be calculated using the same method as the thermal shrinkage rate in the width direction of the heat-shrinkable label 1 calculated by formula (A) when immersed in a 90°C hot water bath, except that the temperature of the hot water bath is 60°C or 70°C.

[0022] <Base Film> As the base film 11 shown in Figure 4, a multilayer film is used in which a first polyester resin layer, a polystyrene resin layer, and a second polyester resin layer are laminated in this order, or a heat-shrinkable plastic film containing a polyester resin film is used. The base film 11 has a longitudinal direction 2 which is the non-shrinking direction and a width direction 3 which is the main shrinking direction. Before printing, for example, the width dimension is 800 mm to 1300 mm and it is a long length that extends continuously for several thousand meters in the longitudinal direction 2. After printing, before being sealed into a tubular shape, it is slit to a width of, for example, 100 mm to 400 mm.

[0023] The base film 11 shown in Figure 4 can be manufactured, for example, as follows. First, a polyester resin raw material and a polystyrene resin raw material are prepared. As the polyester resin raw material, for example, a resin can be used that contains 50 mol% or more of ethylene terephthalate units and amorphous components modified with other glycol components such as 1,4-cyclohexanedimethanol or neopentyl glycol or other dicarboxylic acid components such as isophthalic acid. As the polystyrene resin raw material, for example, a styrene resin such as a styrene-butadiene copolymer resin that easily provides gentle heat shrinkage in the base film 11 can be used.

[0024] Next, an unstretched multilayer film is prepared using the above-mentioned polyester resin raw material and polystyrene resin raw material, or an unstretched polyester resin film is prepared using the above-mentioned polyester resin raw material.

[0025] Unstretched multilayer films can be produced, for example, as follows: First, the polyester resin raw materials and polystyrene resin raw materials are fed into an extruder. Next, the material is extruded from a multilayer die into a three-layer sheet structure, with a polystyrene resin layer in between two polyester resin layers (a first polyester resin layer and a second polyester resin layer). The extruded three-layer sheet is then cooled and solidified. This allows for the production of an unstretched multilayer film. The multilayer film is not limited to a three-layer structure; for example, a five-layer, six-layer, or seven- or more multilayer structure can be used, which includes another resin layer (for example, a mixed resin of polyester resin and polystyrene resin, or a resin layer containing other resin components, adhesive components, etc.) between the polyester resin layer and the polystyrene resin layer. Furthermore, an unstretched polyester resin film can be produced in the same manner as an unstretched multilayer film, except that the polyester resin raw materials are extruded into a single layer or multiple layers. As an unstretched film for multilayer polyester resin films, for example, a film made by laminating three layers of polyester resins of different types (where the presence or ratio of amorphous components differs between the intermediate polyester resin layer and the polyester resin layers on either side, or where recycled PET is laminated to the intermediate polyester resin layer, etc.) can be used.

[0026] The above-mentioned unstretched film can be produced by conventional methods such as melt deposition, but it is preferable to use the melt deposition method (particularly the T-die method) as the method for producing the above-mentioned unstretched film. Furthermore, conventional methods such as co-extrusion (feed block method, multi-manifold method, etc.) can be used as the method for laminating the resin, and it is preferable to use the feed block method.

[0027] A specific example of the co-extrusion method (feed block method) is a method in which raw materials for forming the intermediate layer (polystyrene resin layer) and raw materials for forming the surface layer (polyester resin layer) are fed into multiple extruders set to predetermined temperatures, and the materials are co-extruded from a T-die using a feed block to obtain a predetermined laminate structure. The extrusion temperature varies depending on the type of resin used and is not particularly limited, but it is preferably around 150 to 250°C. An unstretched film (sheet) can be produced by rapidly cooling the polymer co-extruded from the T-die in contact with a cooling drum.

[0028] Next, the unstretched film produced as described above is stretched to impart heat shrinkability, thereby producing a base film 11. The stretching can be performed by biaxial stretching in the longitudinal direction 2 and the width direction 3, or by uniaxial stretching in the width direction 3. As for the stretching method, for example, a roll method, a tenter method, or a tube method can be used. Furthermore, when stretching is performed by biaxial stretching in the longitudinal direction 2 and the width direction 3, the two axes may be stretched simultaneously or sequentially.

[0029] Specific examples of stretching include, for instance, guiding the unstretched film produced as described above to a longitudinal stretching device, and then to a transverse stretching device. More specifically, for example, stretching can be performed by first stretching in the longitudinal direction 2 at a stretching temperature of 65 to 100°C and a stretching ratio of 1.05 to 1.50 times using a roll-type longitudinal stretching method, and then stretching in the width direction 3 at a stretching temperature of 70 to 120°C and a stretching ratio of 3 to 8 times (preferably 4 to 7 times) using a tenter-type transverse stretching method. Alternatively, after stretching in the width direction 3, heat treatment (heat fixing at a temperature lower than the stretching temperature) or relaxation heat treatment with the tenter slightly loosened can be performed while the film is clipped with a tenter. Furthermore, the stretching process may be carried out in multiple stages, and heat treatments such as annealing may be performed. In particular, the thermal shrinkage rate at each temperature and the natural shrinkage rate during storage of the base film 11 can be adjusted by controlling the stretching temperature, stretching ratio, and the temperature and time of the heat treatment.

[0030] The heat-shrinkable label 1 may use a plain base film 11, but the surface of the base film 11 may have some kind of design, such as product information, printed on it in one color or multiple colors. Printing on the surface of the base film 11 can be done, for example, by transferring ink onto the surface of the base film 11 and then drying it to form an ink layer. Printing on the surface of the base film 11 can be done, for example, by gravure printing or flexographic printing. The ink used for printing on the surface of the base film 11 may be water-based ink or oil-based ink.

[0031] <Process for storing rolled products for 24 hours or more> Process 103 for storing rolled products for 24 hours or more involves, for example, storing the rolled products 10 prepared in process 102 in a warehouse or similar environment at an atmosphere of 25°C to 55°C for 24 hours or more. In other words, even if the outside temperature is 25°C or higher, storage can be carried out without the need to keep it below 25°C. Furthermore, in this specification, "storing rolled products for 24 hours or more in an atmosphere of 25°C to 55°C" also includes cases where the rolled products 10 are loaded onto a means of transport such as a truck (vehicle) or ship, and the rolled products 10 are stored on the means of transport during transportation.

[0032] Process 103 is also suitable for cases where the rolled product 10 is stored for 24 hours or more in an atmosphere of 35°C to 55°C. In this case as well, it is possible to manufacture labeled containers that do not have problems with the fitability of the heat-shrinkable label 1 to the container or with the shrinkage finish.

[0033] After storing the roll of heat-shrinkable label 1 in an atmosphere of 25°C to 55°C for 24 hours or more, the heat shrinkage rate in the width direction of the heat-shrinkable label 1 after immersion in a 90°C hot water bath for 10 seconds is 40% or more. Therefore, it is possible to manufacture labeled containers that do not have problems with the heat shrinkage when the heat-shrinkable label 1 is attached to the container, and that have no problems with the finished appearance when attached.

[0034] The thermal shrinkage rate in the width direction of the heat-shrinkable label 1 in a roll of heat-shrinkable label 10 after it has been stored for 24 hours or more in an atmosphere with a temperature of 25°C to 55°C and then immersed in a 90°C hot water bath for 10 seconds can be calculated using the above formula (A).

[0035] <Process of fitting heat-shrinkable labels onto containers> Process 104, in which an automatic attachment machine fits heat-shrinkable labels onto containers, can be carried out, for example, by setting the roll product 10 that has gone through process 103 into the automatic attachment machine, the automatic attachment machine unwinding the flattened heat-shrinkable labels 1 from the roll product 10, cutting the heat-shrinkable labels 1 to predetermined dimensions, opening the unwinded heat-shrinkable labels 1, and then fitting the heat-shrinkable labels 1 onto the container.

[0036] Figure 5 shows a schematic side view of an example of an automatic loading machine used in the embodiment. The automatic loading machine 200 shown in Figure 5 comprises a feeding unit 201, a cutting unit 202, an opening unit 203, and a fitting unit 204. The feeding unit 201, cutting unit 202, opening unit 203, and fitting unit 204 are arranged in this order from vertically above to vertically below the automatic loading machine 200.

[0037] The dispensing unit 201 is configured to dispense a continuous label 100 of the tubular heat-shrinkable label 1 from the roll product 10.

[0038] The cutting unit 202 is configured to cut the label continuum 100 of the heat-shrinkable label 1, which is fed out from the feeding unit 201, to a predetermined size according to the printed design, etc. This makes it possible to produce one heat-shrinkable label 1 from the label continuum 100 of the heat-shrinkable label 1.

[0039] The opening unit 203 is configured to open a single cylindrical heat-shrinkable label 1 that has been folded into a flat shape. As shown in Figure 5, the end of the rod-shaped opening unit 203 on the cutting unit 202 side (upper end) has a tapered wedge shape, and the end on the fitting unit 204 side (lower end) has a circular cross-section. By fitting the heat-shrinkable label 1 from the upper end to the lower end of the opening unit 203 with this shape, the heat-shrinkable label 1 can be opened into a cylindrical shape.

[0040] The fitting unit 204 is configured to allow the heat-shrinkable label 1, which is fitted into the opening unit 203, to be fitted into the container 4 located vertically below the fitting unit 204 by moving it vertically downward. The fitting unit 204 can be configured, for example, as a pair of rollers that can rotate while in contact with the surface of the opening unit 203. The shape of the lower end of the opening unit 203 may be changed to an elliptical shape, a polygonal shape, etc., depending on the shape of the container to be fitted.

[0041] Figure 6 shows a schematic side view of another example of an automatic mounting machine. Unlike the automatic mounting machine in Figure 5, the automatic mounting machine 210 shown in Figure 6 is characterized by comprising an opening and fitting unit 216 that combines opening and fitting functions, and a transfer unit 215 between the cutting unit 202 and the opening and fitting unit 216. The transfer unit 215 is configured to transfer the heat-shrinkable label 1 to the opening and fitting unit 216, for example, as shown in Figure 6. The opening and fitting unit 216 comprises a take-up member 217, a first suction member 218a, a second suction member 218b, a third suction member (not shown), and a fourth suction member (not shown). The take-up member 217, the first suction member 218a, the second suction member 218b, the third suction member, and the fourth suction member each have suction holes. The take-up member 217, the first suction member 218a, the second suction member 218b, the third suction member, and the fourth suction member are configured to hold or open the heat-shrinkable label 1 by suction through the suction holes.

[0042] The opening and fitting unit 216 can be fitted into the container 4 after opening the heat shrinkable label 1, for example, as follows. First, as shown in Figure 6, for example, the take-up member 217 holds the heat shrinkable label 1, which has been transferred from the cutting unit 202, by suction. Next, as shown in the schematic side view of Figure 7, for example, the first suction member 218a, the second suction member 218b, the third suction member (not shown), and the fourth suction member (not shown) move vertically upward to the position of the heat shrinkable label 1 held by the take-up member 217. Next, the heat-shrinkable label 1 is released from its hold by the suction of the take-up member 217, and the outer surface of the flattened heat-shrinkable label 1 is held by the suction of the first suction member 218a, the second suction member 218b, the third suction member, and the fourth suction member. Then, as the suction members 218 separate, the heat-shrinkable label 1 opens up to form a cylindrical shape, as shown in the schematic side view of Figure 8, for example. After that, as shown in the schematic side view of Figure 9, for example, the heat-shrinkable label 1 can be fitted into the container 4 by moving vertically downward while the first suction member 218a, the second suction member 218b, the third suction member, and the fourth suction member hold the cylindrical heat-shrinkable label 1 in suction. The operations shown in Figures 6 to 9 are performed while the take-up member 217, each suction member 218, and the container 4 move along a rotating trajectory (rotary operation). The automatic mounting machines shown in Figures 5 and 6 are disclosed, for example, in Japanese Patent Publication No. 2013-248787 and Japanese Patent No. 5329643.

[0043] Figure 10 shows a schematic perspective view of an example of a container 4 with a heat-shrinkable label 1 fitted onto it. Here, the outer surface 40 of the container 4 comprises a body portion 41 located at the bottom of the container, a shoulder portion 42 located above the body portion 41, and a mouth portion 43 located above the shoulder portion 42. The heat-shrinkable label 1 can be installed, for example, so as to be fitted onto the outer surface 40 of the container 4 from the body portion 41 to the shoulder portion 42.

[0044] Although several examples of automatic mounting machines have been shown, in the process of the automatic mounting machine fitting the heat-shrinkable label onto the container, the heat-shrinkable label 1 may be opened by the automatic mounting machine when it cuts the heat-shrinkable label 1 to a predetermined size.

[0045] FIG. 11 shows a schematic cross-sectional view of an example along XI-XI of FIG. 10. The heat-shrinkable label 1 requires a margin dimension for the fitting suitability to the container by an automatic applicator. However, since it is better to reduce (tighten) the margin dimension so that wrinkles and distortions are less likely to occur during heat shrinkage after fitting, the circumferential length of the inner peripheral surface 1a of the heat-shrinkable label 1 is 15 mm or more and 30 mm or less longer than the circumferential length of the outer peripheral surface 40 of the container 4. It is preferably installed so as to surround the outer peripheral surface 40 of the container 4. In particular, when the circumferential length of the outer peripheral surface 40 of the container 4 is, for example, 180 mm or more and 250 mm or less, the heat-shrinkable label 1 is installed so that the circumferential length of the inner peripheral surface 1a of the heat-shrinkable label 1 is 18 mm or more and 26 mm or less longer than the circumferential length of the outer peripheral surface 40 of the container 4. More preferably, in FIG. 11, the case where the cross-sectional shapes of the outer peripheral surface 40 of the container 4 and the inner peripheral surface 1a of the heat-shrinkable label 1 are circular has been described, but it is not limited to the circular shape and may be polygonal. Further, the heat-shrinkable label 1 may be in a tubular shape with 2 to 4 folds or the like remaining when it is folded flat.

[0046] <Process of adhering the heat-shrinkable label to the outer peripheral surface of the container> Next, the process 105 of adhering the heat-shrinkable label to the outer peripheral surface of the container can be performed, for example, by blowing hot air and / or steam onto the heat-shrinkable label 1 fitted to the container 4, heat-shrinking the heat-shrinkable label 1, and adhering it to the outer peripheral surface 40 of the container 4. As the hot air blown onto the heat-shrinkable label 1, for example, hot air of 80°C or more and 250°C or less can be used. As the steam blown onto the heat-shrinkable label 1, for example, steam generated by a boiler at 100°C or less, preferably 80°C or more and 90°C or less, that is, a mixed state of saturated steam and steam condensed into hot water vapor can be used.

[0047] FIG. 12 shows a schematic plan view of an example of the labeled container obtained by passing through the process 105. In the labeled container 50 shown in FIG. 12, the heat-shrinkable label 1 after heat shrinkage is adhered to the outer peripheral surface 40 of the container 4, and the heat-shrinkable label 1 after heat shrinkage is mounted from the body portion 41 to the shoulder portion 42 of the outer peripheral surface 40 of the container 4.

[0048] Step 105 includes a step of heat - shrinking the heat - shrinkable label 1 by blowing hot air at 150°C to 250°C onto the heat - shrinkable label 1 for 1 to 5 seconds (more preferably 1 to 3 seconds). It is preferable that the heat - shrinkage rate at the maximum shrinkage position of the heat - shrinkable label 1 when the heat - shrinkable label 1 is adhered to the outer peripheral surface 40 of the container 4 is 40% or more. In this case, it is possible to prevent the water wetting of the heat - shrinkable label 1 caused by the blowing of steam, and it is possible to prevent damage to the container 4 and wrinkles on the heat - shrinkable label 1 by blowing hot air for a short time. Furthermore, when the heat - shrinkage rate at the maximum shrinkage position of the heat - shrinkable label 1 is 40% or more, the heat - shrinkable label 1 can be adhered and mounted closely to the constrictions, steps, and parts with different diameters on the outer peripheral surface 40 of the container 4.

[0049] <Heating Device> Fig. 13 shows a schematic side view of an example of a heating device capable of performing Step 105 of adhering the heat - shrinkable label 1 to the outer peripheral surface 40 of the container 4. As shown in Fig. 13, the heating device 300 includes a pre - heating part 301 and a main heating part 302. The pre - heating part 301 is provided upstream of the main heating part 302, and the container 4 with the heat - shrinkable label 1 fitted therein first passes through the pre - heating part 301. In the pre - heating part 301, the container 4 with the heat - shrinkable label 1 fitted therein is pre - heated to a temperature just before the heat - shrinkable label 1 starts to shrink or to a temperature at which it shrinks slightly. After passing through the pre - heating part 301, the container 4 passes through the main heating part 302. The main heating part 302 includes a plurality of hot - air delivery means and can heat - shrink the heat - shrinkable label 1 by blowing hot air at 150°C to 250°C onto the heat - shrinkable label 1, for example, for 1 to 5 seconds, so as to adhere it to the outer peripheral surface 40 of the container 4. Thereby, the labeled container 50 can be produced.

[0050] <Hot Air Discharge Means> Figure 14 shows a schematic top view of an example of the internal configuration of the heating unit 302 shown in Figure 13. The heating unit 302 shown in Figure 14 is equipped with a plurality of hot air discharge means 303. The hot air discharge means 303 are arranged in parallel on both sides of the container 4 fitted with the heat-shrinkable label 1 that passes through the heating unit 302, parallel to the direction of travel. At this time, the hot air outlets 304 of the hot air discharge means 303 are set to face the direction of travel axis of the container 4 fitted with the heat-shrinkable label 1. The hot air (solid line) supplied to the hot air discharge means 303 is blown from the hot air outlets 304 toward the container 4 fitted with the heat-shrinkable label 1 that passes in front of the hot air discharge means 303. The heating unit 302 is particularly preferable to blow hot air strongly to shrink the heat-shrinkable label 1 in a short time and attach it to the container 4. In this case, it is preferable to heat the heat-shrinkable label 1 to a temperature of 80°C or higher using hot air to cause shrinkage.

[0051] Figure 15 shows a schematic top view of another example of the internal configuration of the heating unit 302 shown in Figure 13. The heating unit 302 shown in Figure 15 is equipped with four hot air delivery means 303a to 303d. The hot air delivery means 303a to 303d can be arranged at equal intervals, for example, to surround the container 4 fitted with the heat shrinkable label 1. The heating unit 302 shown in Figure 15 is characterized in that the hot air outlets 304a to 304d are arranged such that they are each tilted by an angle θ on the same side (to the right in the example shown in Figure 15) with respect to the direction of the central axis 305 of the container 4 (direction of the dashed arrow). In this case, it is preferable to arrange the hot air delivery means 303a to 303d so that the hot air outlets 304a to 304d do not face each other. As a result, the hot air supplied to the hot air delivery means 303a to 303d is not blown from the hot air outlets 304a to 304d toward the container 4 fitted with the heat-shrinkable label 1, but rather blown in a direction inclined by an angle θ on the same side with respect to the direction of travel in a straight line toward the central axis 305 of the container 4. Therefore, the hot air blown out from the hot air outlets 304a to 304d interfere with each other, forming a vortex of hot air around the container 4 (see the solid arrow in Figure 15). This vortex of hot air heats the surface of the heat-shrinkable label 1 uniformly and quickly, resulting in a labeled container with a good finish, free from wrinkles and unevenness in the heat-shrinkable label 1. From the viewpoint of obtaining a labeled container with a good finish, free from wrinkles and unevenness in the heat-shrinkable label 1, the angle θ is preferably 30° or less.

[0052] By following steps 102, 103, 104, and 105 described above, a labeled container can be manufactured.

[0053] <Effects> In the manufacturing method of the labeled container of the embodiment, the heat shrinkage rate in the width direction of the heat shrinkable label prepared in step 102 is 40% or more after immersion in a 90°C hot water bath for 10 seconds, and the natural shrinkage rate in the width direction of the heat shrinkable label 1 after storage of the roll product in a 55°C atmosphere for 7 days is 0.5% or less. Furthermore, the manufacturing method of the labeled container of the embodiment includes step 103 in which the roll product is stored for 24 hours or more in an atmosphere of 25°C to 55°C (preferably 35°C to 55°C), and the heat shrinkage rate in the width direction of the heat shrinkable label 1 after step 103 is 40% or more after immersion in a 90°C hot water bath for 10 seconds.Therefore, since the heat shrinkable label 1 does not shrink naturally, the step of keeping the roll product 10 of the heat shrinkable label 1 cool for storage is unnecessary, it is possible to accommodate a variety of heat shrinkage methods, and it is possible to manufacture a labeled container in which there are no problems with the finish when the heat shrinkable label 1 is attached to the container 4.

[0054] <Process for preparing roll products for Experimental Examples 1 to 8> Multiple types of roll products of heat-shrinkable labels were prepared, each consisting of a base film with various widthwise heat shrinkage rates adjusted by appropriately changing the manufacturing conditions, etc. These were designated as roll products for Experimental Examples 1 to 8. The base film constituting the heat-shrinkable labels of roll products for Experimental Examples 1 to 3 and 6 is a 35 μm thick multilayer film in which a first polyester resin layer, a polystyrene resin layer, and a second polyester resin layer are laminated in that order. The base film constituting the heat-shrinkable labels of roll products for Experimental Examples 4, 7, and 8 is a 20 μm thick polyester resin film. The base film constituting the heat-shrinkable label of roll product for Experimental Example 5 is a 30 μm thick polyester resin film. Text and designs and solid white printing were performed on the base film using water-based ink, slit to a predetermined width, and then center-sealed (bag-making) to form a tubular heat-shrinkable label. The roll products for Experimental Examples 1 to 8 were then produced by folding the tubular heat-shrinkable label flat and winding it up. In the following, the heat-shrinkable labels of the roll products in Experimental Examples 1 to 8 will be referred to as "Heat-shrinkable labels of Experimental Examples 1 to 8," respectively.

[0055] First, the widthwise heat shrinkage rates of the heat-shrinkable labels for Experimental Examples 1 to 8 were calculated as follows: (i) widthwise heat shrinkage rate [%] when stored at 25°C, (ii) widthwise heat shrinkage rate [%] after 7 days of storage in an atmosphere at 55°C, (iii) difference in shrinkage rate between the widthwise heat shrinkage rate when stored at 25°C and the widthwise heat shrinkage rate after 7 days of storage in an atmosphere at 55°C, (iv) maximum widthwise heat shrinkage rate [%], and (v) natural shrinkage rate [%]. The results are shown in Table 1.

[0056] (i) The thermal shrinkage rate in the width direction [%] when stored at 25°C was calculated by cutting the thermal shrinkage labels of Experimental Examples 1 to 8, which had been stored in an atmosphere of 25°C or lower after their preparation, along the longitudinal direction 2 and unfolding them into a flat surface, and immersing each in a hot water bath of 60°C to 100°C for 10 seconds under no load, and using the width direction length of the thermal shrinkage labels before and after immersion, according to the following formula (Equation A').

[0057] Widthwise heat shrinkage rate [%] = 100 × [{(Widthwise length of heat shrinkable label before immersion) - (Widthwise length of heat shrinkable label after immersion)} / (Widthwise length of heat shrinkable label before immersion)] ... (Equation A')

[0058] (ii) The thermal shrinkage rate in the width direction [%] after storage for 7 days in an atmosphere of 55°C was calculated by immersing the thermal shrinkage labels of Experimental Examples 1 to 8, which had been stored in an atmosphere of 25°C or lower and then stored (aged) for 7 days in an atmosphere of 55°C (humidity 1% to 2%), in a hot water bath of 60°C to 100°C for 10 seconds under no load, and measuring the width direction length of the thermal shrinkage labels before and after immersion using the following formula (Equation B').

[0059] Widthwise heat shrinkage rate [%] = 100 × [{(Widthwise length of the heat shrinkable label before immersion after aging) - (Widthwise length of the heat shrinkable label after immersion after aging)} / (Widthwise length of the heat shrinkable label before immersion after aging)] ... (Equation B')

[0060] (iii) The difference in shrinkage rate [%] between the thermal shrinkage rate in the width direction when stored at 25°C and the thermal shrinkage rate in the width direction after storage in an atmosphere at 55°C for 7 days was calculated by subtracting (ii) the thermal shrinkage rate in the width direction after storage in an atmosphere at 55°C for 7 days [%] from (i) the thermal shrinkage rate in the width direction when stored at 25°C [%].

[0061] (iv) The maximum thermal shrinkage rate in the width direction [%] was calculated by immersing each of the thermal shrinkable labels from Experimental Examples 1 to 8, which had been stored in an atmosphere of 25°C or lower immediately after the thermal shrinkable labels were made, in a glycerin bath at 140°C for 10 seconds under no load, and using the width direction length of the thermal shrinkable labels before and after immersion, according to the following formula (Equation A'').

[0062] Maximum thermal shrinkage ratio in the width direction [%] = 100 × [{(width of the heat-shrinkable label before immersion) - (width of the heat-shrinkable label after immersion)} / (width of the heat-shrinkable label before immersion)] ... (Equation A'')

[0063] (v) The natural shrinkage rate [%] was calculated from the longitudinal or widthwise length of the heat-shrinkable label before and after 7 days of storage (aging) in an atmosphere of 55°C (without immersion in a hot water bath or glycerin bath) using the following formula (Formula F). In formula (Formula F) below, the longitudinal length is selected when calculating the longitudinal natural shrinkage rate [%] after aging, and the widthwise length is selected when calculating the widthwise natural shrinkage rate [%] after aging.

[0064] Natural shrinkage rate [%] = 100 × [{(Length or width of the heat-shrinkable label before aging) - (Length or width of the heat-shrinkable label after aging)} / (Length or width of the heat-shrinkable label before aging)] ... (Equation F)

[0065]

[0066] <Process of storing rolled products for more than 24 hours> Next, as a process of storing each of the rolled products from Experimental Examples 1 to 8, which were prepared as described above, in an atmosphere of 25°C to 55°C for more than 24 hours, they were stored for 168 hours (7 days) in an atmosphere of the maximum temperature of 55°C.

[0067] <Process of fitting heat-shrinkable labels to containers> Next, the rolls of each of the experimental examples 1 to 8, after being stored for 24 hours or more in an atmosphere of 25°C to 55°C, were set in an automatic loading machine. The automatic loading machine unfurled the heat-shrinkable labels from the rolls, cut the unfurled heat-shrinkable labels to the predetermined dimensions, and after opening the cut heat-shrinkable labels, fitted them into the containers. The containers used were PET bottle containers with a body diameter of 65 mm (the diameter is the maximum diameter of the circular part, and has a nearly hexagonal shape with six panel shapes) and a shoulder part located above the body with a smaller diameter than the body, filled with tap water at 15°C. At this time, it was confirmed that the heat-shrinkable labels of Examples 6 and 8 had shrunk naturally and were unsuitable for attachment.

[0068] Next, PET bottle containers fitted with the heat-shrinkable labels of Experimental Examples 1 to 8 were passed through a steam tunnel at atmospheric pressure (tunnel length 3 m, tunnel temperature approximately 85°C (variable between approximately 80°C and 90°C depending on the measurement position, container passage, etc.)). The heat-shrinkable labels were heated for 3 seconds to cause thermal shrinkage, thereby firmly attaching them to the outer surface of the PET bottle container. Here, the steam outlet inside the steam tunnel was adjusted so that it was directed downwards towards the PET bottle container in the initial stage, to an intermediate position in the middle stage, and to heat the entire container in the final stage. Furthermore, the required thermal shrinkage rate at the maximum thermal shrinkage position of the heat-shrinkable labels of Experimental Examples 1 to 8 at the uppermost end of the shoulder of the PET bottle container was determined to be 40-45%, due to variations in the placement of the heat-shrinkable labels.

[0069] Next, the finish of the heat-shrinkable labels in Experimental Examples 1-8, which were attached to PET bottle containers, was visually evaluated according to the following criteria. The results are shown in Table 2.

[0070] (Criteria for evaluating finish) A: No wrinkles, good finish B: Some wrinkles, but good C: Not as good as A or B due to insufficient heat shrinkage D: Has shrunk naturally and is unsuitable for wearing

[0071]

[0072] <Results of finish evaluation of heat-shrinkable labels in Experimental Examples 1-8 by steam heating> As is clear from the results in Table 2, in the process of preparing rolls of heat-shrinkable labels containing multilayer films, when rolls of heat-shrinkable labels in Experimental Examples 1-3 were prepared, the widthwise heat shrinkage rate after immersion in a 90°C hot water bath for 10 seconds was 40% or more, and the widthwise natural shrinkage rate after storage in a 55°C atmosphere for 7 days was 0.5% or less, a finish comparable to that of the heat-shrinkable label in Experimental Example 6, which did not have a widthwise heat shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days, was obtained before the aging process described above. After the aging process described above, the heat-shrinkable label in Experimental Example 6 became difficult to attach due to natural shrinkage, but the heat-shrinkable labels in Experimental Examples 1-3 showed less natural shrinkage and a good finish was obtained.

[0073] Furthermore, as is clear from the results in Table 2, regarding heat-shrinkable labels containing polyester resin film, the heat-shrinkable labels of Experimental Examples 4-5, which had a widthwise heat shrinkage rate of 40% or more after immersion in a 90°C hot water bath for 10 seconds and a widthwise natural shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days, achieved a comparable finish before aging compared to the heat-shrinkable labels of Experimental Examples 7-8, which did not have a widthwise natural shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days. After aging, the heat-shrinkable labels of Experimental Example 8 became difficult to attach due to natural shrinkage, while the heat-shrinkable labels of Experimental Examples 4-5 showed less natural shrinkage and achieved a good finish.

[0074] <Evaluation of the finish of heat-shrinkable labels in Experimental Examples 1-8 by hot air heating> Next, the finish of the heat-shrinkable labels in Experimental Examples 1-8 attached to PET bottle containers was evaluated in the same manner as the evaluation by steam heating, except that the PET bottle containers fitted with each of the heat-shrinkable labels in Experimental Examples 1-8 were passed through a hot air tunnel at atmospheric pressure. The results are shown in Table 3. The hot air tunnel used was a Tornado Tunnel PURE2001 manufactured by Japan Technology Solutions Co., Ltd. The hot air tunnel had a length of 2m and consisted of a first zone and a second zone where hot air was blown from the side, and a tornado zone (third zone) where hot air was blown in a swirling manner around the container (see Figure 15). The first zone was set to 90°C, the second zone to 120°C, and the tornado zone to 180°C, and the passage time through the tornado zone was set to approximately 3 seconds.

[0075]

[0076] <Results of finish evaluation of heat-shrinkable labels in Experimental Examples 1-8 by hot air heating> As is clear from the results in Table 3, for heat-shrinkable labels including multilayer films, the heat-shrinkable labels in Experimental Examples 1-3, which had a widthwise heat shrinkage rate of 40% or more after immersion in a 90°C hot water bath for 10 seconds and a widthwise natural shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days, achieved a similar finish before aging compared to the heat-shrinkable label in Experimental Example 6, which did not have a widthwise natural shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days. After aging, the heat-shrinkable label in Experimental Example 6 became difficult to attach due to natural shrinkage, but Experimental Examples 1-3 showed less natural shrinkage and a good finish.

[0077] Furthermore, as is clear from the results in Table 3, regarding heat-shrinkable labels containing polyester resin film, the heat-shrinkable labels of Experimental Examples 4-5, which had a widthwise heat shrinkage rate of 40% or more after immersion in a 90°C hot water bath for 10 seconds and a widthwise natural shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days, exhibited less natural shrinkage compared to the heat-shrinkable labels of Experimental Examples 7-8, which did not have a widthwise heat shrinkage rate of 0.5% or less after storage in a 55°C atmosphere for 7 days. A good finish could be obtained by fitting the labels into a container and heating them with hot air, either before or after the aging process. After the aging process, the heat-shrinkable labels of Experimental Examples 7-8 became difficult to attach due to natural shrinkage, while Experimental Examples 4-5 showed less natural shrinkage and a good finish.

[0078] As described above, the embodiments and experimental examples have been explained, but it was also planned from the outset that the configurations of each of the embodiments and experimental examples described above could be combined as appropriate.

[0079] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope of equivalents of the claims are intended.

[0080] The manufacturing method for labeled containers according to this embodiment eliminates the need for a step of keeping rolls of heat-shrinkable labels cool during storage, can accommodate a variety of heat-shrinkage methods, and can be used to manufacture labeled containers with no problems in the finished appearance of the heat-shrinkable labels.

[0081] 1 Heat shrinkable label, 1a Inner surface, 2 Vertical direction, 2' Virtual axis, 3 Width direction, 4 Container, 10 Roll product, 11 Base film, 40 Outer surface, 41 Body, 42 Shoulder, 43 Mouth, 50 Labeled container, 100 Label continuous, 200 Automatic mounting machine, 201 Feed unit, 202 Cutting unit, 203 Opening unit, 204 Fitting unit, 210 Automatic mounting machine, 215 Transfer unit, 216 Opening fitting unit, 217 Take-up member, 218a First suction member, 218b Second suction member, 300 Heating device, 301 Preheating section, 302 Main heating section, 303, 303a, 303b, 303c, 303d Hot air sending means, 304, 304a, 304b, 304c, 304d Hot air outlet, 305 Central axis.

Claims

1. A step of preparing a roll of heat-shrinkable labels, wherein the heat shrinkage rate in the width direction after immersing the heat-shrinkable labels in a 90°C hot water bath for 10 seconds is 40% or more, and the natural shrinkage rate in the width direction of the heat-shrinkable labels after storing the roll in a 55°C atmosphere for 7 days is 0.5% or less; a step of storing the roll in a 25°C to 55°C atmosphere for 24 hours or more; a step of setting the roll in an automatic loading machine, the automatic loading machine unwinding the heat-shrinkable labels from the roll, cutting the heat-shrinkable labels to predetermined dimensions, opening the heat-shrinkable labels, and then fitting the heat-shrinkable labels into a container; and a step of heat-shrinking the heat-shrinkable labels fitted into the container by blowing hot air and / or steam onto the heat-shrinkable labels, thereby making the heat-shrinkable labels adhere tightly to the outer surface of the container. A method for manufacturing a labeled container, wherein the heat shrinkage rate of the heat shrinkage rate in the width direction of the heat shrinkage rate 2. The method for manufacturing a labeled container according to claim 1, wherein the step of storing the rolled product for 24 hours or more includes storing the rolled product for 24 hours or more in an atmosphere of 35°C to 55°C.

3. The method for manufacturing a labeled container according to claim 1, wherein the step of adhering the heat-shrinkable label to the outer surface of the container includes a step of heat-shrinking the heat-shrinkable label by blowing hot air at 150°C to 250°C onto the heat-shrinkable label for 1 to 5 seconds, and the heat shrinkage rate at the maximum shrinkage position of the heat-shrinkable label when the heat-shrinkable label is adhering to the outer surface of the container is 40% or more.

4. The method for manufacturing a labeled container according to claim 1, wherein the step of adhering the heat-shrinkable label to the outer surface of the container includes the step of blowing hot air onto the heat-shrinkable label using a plurality of hot air dispensing means provided around the container, each of the plurality of hot air dispensing means being equipped with a hot air outlet, and the plurality of hot air dispensing means are arranged such that the hot air outlets are oriented in a direction inclined to the same side with respect to the direction in which they are oriented in a direction perpendicular to the central axis of the container.

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