tape

Abstract

This invention provides a tape suitable for edge treatment processing to cover the end faces of blanks used in paper containers. [Solution] One aspect of the present invention is a tape having a thermoplastic resin on its surface, used for processing the end faces of blanks used as the body of paper containers. The thickness of the tape is 25 to 200 μm. In the end face processing described above, the tape is positioned so that its longitudinal direction coincides with the longitudinal direction of the end face of the blank, and the tape is folded back so that the approximate center of the longitudinal direction of the tape becomes a fold, and is attached to one side and the other side of the blank so as to cover the end face of the blank.

Description

Technical Field

[0001] The present invention relates to a tape. In particular, the present invention relates to a tape used for end face processing of a blank constituting a paper container such as a paper cup.

Background Art

[0002] Conventionally, since the material of a paper container such as a paper cup is inferior in water resistance and gas barrier properties with only the base paper, a paper laminate in which a resin layer is laminated as a water-stopping layer on the surface on the inner surface side of the container of the base paper (paper base material) has been used. The inverted frustum-shaped cylindrical body of a paper cup is formed by winding a blank punched out in a fan shape, overlapping one side end portion (adhesive end portion) on the inner surface side and the other side end portion on the outer surface side, and adhesively bonding them in a liquid-tight manner. It is known to perform end portion treatment so that the base paper is not exposed and water resistance is ensured with respect to the end face of one side end portion of the blank on the inner surface side. As a method of end face treatment of the blank, an end face treatment (see, for example, Patent Documents 1 to 3) is known in which a separately prepared strip-shaped water-resistant tape is attached to the side end portion of the blank over the front and back surfaces to cover the end face.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When performing edge finishing by attaching strip-shaped tape to the side edge of a blank, as disclosed in Patent Documents 1 to 3, it is difficult to adhere the strip-shaped tape to the side edge surface of the blank at high speed and with high precision, and adhesion defects such as wrinkles and peeling of the tape may occur. Furthermore, even if tape is adhered to the side edge surface of the blank, folding it back to the back side to cover the edge of the blank requires a complex mechanism and a lot of time, and therefore, it is difficult to say that the simplification of the device structure and the shortening of production time have been sufficiently achieved.

[0005] To solve the above problems, the inventors have developed a tape-applying end-face processing device that has a simple structure, suppresses the occurrence of bonding defects such as wrinkles and curling of the tape even when the end face of a blank is processed at high speed, and can automatically fold the tape back to the back side of the blank while conveying the blank, thereby enabling tape end-face processing to be performed in a short time and with a high yield, resulting in high production efficiency.

[0006] Furthermore, the inventors have found that there is room for improvement regarding the occurrence of tape application defects such as wrinkles and the bendability of the tape during end-face processing using a tape application end-face processing device. This invention addresses the above-mentioned problems and aims to provide a tape suitable for edge treatment processing to cover the end faces of blanks used in paper containers. [Means for solving the problem]

[0007] One aspect of the present invention is a tape. The tape is used for processing the end face of a blank used as the body of a paper container, and has a thermoplastic resin on its surface, with a layer thickness of 25 to 200 μm, and in the end face processing, the tape is positioned so that the longitudinal direction of the tape coincides with the longitudinal direction of the end face of the blank, and the tape is attached to one side and the other side of the blank so as to cover the end face of the blank in a state where it is folded back so that the approximate center of the longitudinal direction of the tape becomes a fold. In the tape according to the above embodiment, the layer configuration of the tape may be one selected from the group consisting of a laminate in which polyethylene, polyethylene terephthalate, and polyethylene are laminated in that order, a laminate in which polyethylene, aluminum foil, and polyethylene are laminated in that order, a laminate in which polyethylene, nylon, and polyethylene are laminated in that order, and a single layer of polyethylene. Furthermore, in the tape according to the above embodiment, the loop stiffness measured under the following conditions may be 0.5 to 100 mN. (Loop stiffness measurement conditions) Device: LOOP STIFFNESS TESTER DA type (manufactured by Toyo Seiki Co., Ltd.) Tape width: 10mm Loop length: 70mm Speed: 3.3mm / sec Indentation amount: 10mm Measurement environment: Temperature 23°C, relative humidity 50% [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a technology relating to a tape suitable for edge treatment processing that covers the edge surface of a blank used in a paper container. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing an example of the configuration of a blank and tape whose ends are processed by a tape end-face processing device. Figure 1(a) is a plan view, and Figure 1(b) is a cross-sectional view along line XX in Figure 1(a). [Figure 2] Figure 2 is a perspective view showing an example of the configuration of a tape application end-face processing device. [Figure 3A] Figure 3A is a perspective view showing the blank heating mechanism of the tape application end-face processing device shown in Figure 2. [Figure 3B] Figure 3B is a cross-sectional view showing the blank heating mechanism of the tape application end-face processing device shown in Figure 2. [Figure 4]FIG. 4 is a schematic view showing a state where a tape is bonded to the front surface side of a blank by a tape bonding mechanism, FIG. 4(a) is a plan view, and FIG. 4(b) is a sectional view taken along line Y-Y. [Figure 5A] FIG. 5A is a perspective view showing the tape bonding mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 5B] FIG. 5B is a side view showing the tape bonding mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 5C] FIG. 5C is a partially enlarged sectional view showing the tape bonding mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 6A] FIG. 6A is a perspective view showing the tape temporary fixing mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 6B] FIG. 6B is a side view showing the tape temporary fixing mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 7] FIG. 7 is a schematic plan view showing a state where a tape is temporarily fixed to the front surface side of a blank by a tape temporary fixing mechanism. [Figure 8] FIG. 8 is a side view showing the tape folding mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 9] FIG. 9 is a sectional view showing each cross section in the tape folding mechanism of the tape bonding end face processing apparatus of FIG. 2. [Figure 10A] FIG. 10A is a perspective view showing the first welding part of the tape bonding end face processing apparatus of FIG. 2. [Figure 10B] FIG. 10B is a sectional view showing the first welding part of the tape bonding end face processing apparatus of FIG. 2. [Figure 11A] FIG. 11A is a perspective view showing the second welding part of the tape bonding end face processing apparatus of FIG. 2. [Figure 11B] FIG. 11B is a sectional view showing the second welding part of the tape bonding end face processing apparatus of FIG. 2.

Embodiments for Carrying Out the Invention

[0010] Embodiments of the present invention will be described in detail below. In this specification, unless otherwise specified, the notation "a~b" in the description of numerical ranges means a or greater and b or less.

[0011] A tape according to an embodiment, and a tape application end-face processing device for covering the blank end face with the tape, will be described with reference to the drawings.

[0012] The tape-applied end-face processing device is a device for continuously and automatically performing end-face processing on blanks, which are the raw materials for paper containers such as paper cups, by covering them with long, strip-shaped tapes. The purpose of this end-face processing is to prevent the base paper from being exposed at the adhesive end of the blank, which will be located on the inner surface of the container, thereby suppressing the penetration of liquid from the blank end and ensuring high water resistance for the container. The blank B, which is the workpiece of the tape-applied end-face processing device, is, for example, used for forming the body of a paper cup, and as shown in Figure 1(a), it is fan-shaped in plan view. A fan shape is a shape obtained by cutting a single ring from a central point (the pivot of the fan) with two straight lines that radiate outwards at acute angles to each other. In the tape-applied end-face processing device, a strip of tape T is applied to the side end (adhesive end) which is made up of straight lines (which may have partial notches).

[0013] 〔blank〕 Blank B can be obtained by punching out a paper laminate 1 into a predetermined shape. The punching method is not particularly limited and can be carried out using, for example, various known punching devices. As shown in Figure 1(b), the paper laminate 1 is formed by forming resin layers 3, 3, which are water-sealing layers, on both surfaces of the base paper 2, which is the main material. From the viewpoint of obtaining water resistance for the paper container that will be manufactured by assembling the blank B, these resin layers 3 only need to be formed on the surface that will be on the inner surface of the container. The paper laminate 1 may also have a laminated structure of three or more layers, and each resin layer 3 may be made of different resin materials. Furthermore, a barrier layer, a printed layer, an adhesive layer, etc., made of a metal vapor deposition layer, for example, may be provided.

[0014] The thickness of blank B (thickness of paper laminate 1) is, for example, 150 to 450 μm. Furthermore, the thickness of the resin layer 3 is such that heat sealing properties are achieved when the blanks B are bonded together to assemble the paper container. For example, it can be in the range of 10 to 100 μm, and the thickness can be set according to the parts to be bonded.

[0015] As the base paper 2, various known base papers can be used depending on the shape of the paper container, the desired strength, etc. Base paper 2 has a basis weight of 150-330 g / m². 2 Those within the range can preferably be used.

[0016] Various known water-resistant resin materials can be used as the resin material for forming the resin layer 3. Furthermore, materials that combine water resistance and heat-sealability are preferably used, such as polyolefin resins like polyethylene and polypropylene, polyvinyl alcohol resins, acrylic acid resins, methacrylic acid resins, vinyl chloride resins, polyvinylidene chloride resins, vinyl acetate resins, polyurethane resins, polyester resins like polyethylene terephthalate, polyamide resins like nylon 6 and nylon 6,6, polystyrene resins, phenolic resins, and mixtures thereof. Of these, polyethylene resin is preferred from the viewpoint of water resistance, heat-sealability, and glass transition temperature.

[0017] 〔tape〕 The tape T according to this embodiment is used for processing the end face of a blank B used as the body of a paper container (see the tape application end face processing device described later). In the above end face processing, the tape T is positioned so that the longitudinal direction of the tape T coincides with the longitudinal direction of the end face of the blank B, and is applied to one side and the other side of the blank B so as to cover the end face of the blank B in a state where the tape T is folded back so that the approximate center of the longitudinal direction of the tape T becomes a fold.

[0018] The tape T, which is attached to the side edge of blank B, is made of a film having a thermoplastic resin on its surface that has heat-sealing properties and can be welded to blank B.

[0019] Tape T may have a single-layer structure or a multi-layer structure. The thickness (total thickness) of tape T is preferably 25 to 200 μm, and more preferably 50 to 100 μm, taking into consideration its foldability and durability.

[0020] The layer configuration (layer structure) of tape T is selected from the group consisting of, for example, a laminate in which polyethylene and polyethylene terephthalate / polyethylene are stacked in that order, a laminate in which polyethylene, aluminum foil, and polyethylene are stacked in that order, a laminate in which polyethylene, nylon, and polyethylene are stacked in that order, and a single layer of polyethylene.

[0021] The thickness of the resin layer located on the surface of tape T is preferably 15 μm or more. This improves the sealing performance when the lid is sealed after the paper container has been molded.

[0022] Furthermore, it is preferable that the layers of tape T include a high-melting-point material with a melting point of 125°C or higher. This helps to suppress the occurrence of pinholes and film tears during the processing and molding of tape T.

[0023] Tape T is supplied to the tape bonding mechanism 120, which will be described in detail later, as a tape roll in which an uncut, long, narrow tape is wound. The width of tape T is, for example, 5 to 20 mm, and preferably 10 mm. If the width of tape T is too large, it becomes unavoidable to enlarge the tape folding mechanism, and if the width of tape T is too small, it may not be possible to reliably weld it to the front and back surfaces of the side edges of blank B.

[0024] Tape T preferably has a loop stiffness of 0.5 to 100 mN as measured under the following conditions. (Loop stiffness measurement conditions) Device: LOOP STIFFNESS TESTER DA type (manufactured by Toyo Seiki Co., Ltd.) Tape width: 10mm Loop length: 70mm Speed: 3.3mm / sec Indentation amount: 10mm Measurement environment: Temperature 23°C, relative humidity 50%

[0025] [Tape application end-face processing device] A tape application end-face processing apparatus for performing end-face coating on a blank B using tape T according to an embodiment will be described.

[0026] Figure 2 is a perspective view showing an example of the configuration of the tape application end-face processing device 100. The tape application end-face processing device 100 performs end-face processing by applying a long tape T to the side end (adhesive end) of a blank B and covering the end face E of the side end. As shown in Figure 2, the tape application end-face processing device 100 includes a transport mechanism 101, a blank heating mechanism 110, a tape bonding mechanism 120, a tape temporary fastening mechanism 130, a tape folding mechanism 140, a first welding section 150, and a second welding section 160.

[0027] The blank heating mechanism 110, tape bonding mechanism 120, tape temporary fastening mechanism 130, tape folding mechanism 140, first welding section 150, and second welding section 160 are arranged from the upstream side along a linear transport path. Each step of the tape-bonded end-face processing method is performed sequentially as the blank B is transported. Furthermore, the blank heating mechanism 110, tape bonding mechanism 120, tape temporary fastening mechanism 130, tape folding mechanism 140, first welding section 150, and second welding section 160 are controlled to operate in conjunction with each other during intermittent transport by the transport mechanism 101. This allows for continuous end-face processing, where the end face E of the side end of the blank B is covered with tape T, using the tape-bonded end-face processing device 100.

[0028] The end-face processing speed of the blank B by the tape-applied end-face processing device 100 is, for example, 120 to 180 sheets / min, and preferably 150 sheets / min or more.

[0029] The details of the tape application end-face processing device 100 will be described below.

[0030] [Conveying mechanism] The conveying mechanism 101 is a mechanism that continuously and intermittently conveys the blank B in one direction. Specifically, the conveying mechanism 101 conveys the blank B linearly so that the longitudinal direction (the direction in which the side edge F extends) of the end face E of the side end of the blank B to be processed coincides with the conveying direction. Furthermore, the conveying mechanism 101 has a conveying lane 102, and it is preferable to support and convey the central part of the blank B so that, for example, 35 to 50 mm from the end face E of the blank B protrudes outward from the conveying lane 102, with the side end of the blank B to be processed floating in the air (see Figure 3B).

[0031] In the conveying mechanism 101 of the tape application end-face processing device 100, a conveying method using a belt conveyor with vacuum suction is employed. However, the specific conveying method is not particularly limited as long as it can achieve intermittent conveying, and various known configurations can be adopted.

[0032] [Blank heating mechanism] The blank heating mechanism 110 is a mechanism that heats the front and back surfaces of the side edges of the blank B. The blank heating mechanism 110 raises the temperature of the entire blank B and melts the resin layer 3 on the front and back surfaces of the side edges of the blank B. Specifically, as shown in Figures 3A and 3B, the blank heating mechanism 110 includes a heating unit 111 that heats the surface side of the blank B's side end and a heating unit 116 that heats the back side of the blank B's side end, both of which are provided on the transport path of the blank B's side end.

[0033] By simultaneously heating both the front and back surfaces of the side edges of blank B, sufficient heat can be applied to the side edges of blank B even when the edge processing of blank B is performed at high speed, ensuring that the temperature of blank B rises reliably, and that the tape T can be reliably bonded to blank B in the subsequent tape bonding mechanism 120.

[0034] The heating units 111 and 116 are each positioned on the transport path at the side end of the blank B so as not to be in contact with the blank B. This allows the heating process to be performed simply by transporting the blank B in the transport direction and stopping it at a predetermined position. The heating units 111 and 116 each consist of a hot air heater. The hot air outlets 112 and 117, from which the hot air is blown out, are positioned 3 to 8 mm (5 mm in this embodiment) away from the front and back surfaces of the side edge of the blank B. The hot air outlets 112 and 117 are each formed from a number of tiny holes arranged along a length approximately equal to the longitudinal direction of the side edge of the blank B, but the shape of the hot air outlets is not limited as long as the side edge of the blank B can be heated.

[0035] In the blank heating mechanism 110, it is sufficient for the area including the adhesive edge regions A1 and A2 on the front and back surfaces of the side edge of the blank B to be heated to a predetermined temperature. For example, the area 10 mm inward from the side edge F is heated. The temperature of the hot air from the heating section 111 facing the surface of the blank B can be, for example, 440°C, and the temperature of the hot air from the heating section 116 facing the back surface of the blank B can be, for example, 300°C. The temperatures of the heating sections 111 and 116 on the surface and back surfaces of the blank B may be the same, but since the tape T is attached to the surface side of the side edge of the blank B in the tape bonding mechanism 120 described later, it is preferable to set the temperature of the heating section 111 facing the surface of the blank B to be higher. If the temperatures of the heating sections 111 and 116 are excessively high, the resin forming the resin layer 3 may foam due to the moisture in the base paper 2 of the blank B.

[0036] The specific heating method for the blank B in the blank heating mechanism 110 is not limited to a method using hot air, but can employ various known configurations as long as the front and back surfaces of the side edges of the blank B can be heated to a predetermined temperature. For example, a heating method using a direct flame plate may be employed.

[0037] [Tape bonding mechanism] The tape bonding mechanism 120 is a mechanism that performs a tape bonding process in which a portion T1 consisting of approximately half the width of a pre-cut tape T (hereinafter referred to as the "left half") is bonded to the adhesive end region A1 at the side edge of the surface (one side) of the blank B. As shown in Figures 4(a) and (b), the tape bonding mechanism 120 supplies tape T cut to a length corresponding to the side edge of the blank B at the bonding point P such that the longitudinal direction of the tape T coincides with the blank transport direction, and while transporting the blank B, the left half T1 of the tape T is bonded to the adhesive end region A1 on the surface side of the blank B, and the right half T2 of the tape T is left in an ear-like state that protrudes outward (to the right in Figures 4(a) and (b)) from the side edge F of the blank B. For example, tape T has a width of 10 mm, with the left half T1 of tape T having a width of 4.7 mm and the remaining right half having a width of 5.3 mm.

[0038] Specifically, the tape bonding mechanism 120 includes a tape transport unit 121, a tape cutting unit 122, and a bonding unit 123, as shown in Figures 5A, 5B, and 5C. The tape transport unit 121 feeds out an uncut tape T from a tape roll (not shown) and transports it along the tape transport path while applying tension with a tension roll or the like as needed. The tape cutting unit 122 cuts the tape T in the tape width direction perpendicular to the tape transport direction in the tape transport path. The bonding unit 123 is located downstream of the tape transport path of the tape cutting unit 122 and bonds the cut tape T to the adhesive end region A1 on the surface side of the blank B.

[0039] The tape transport belt 125 is stretched across multiple tension rollers and is driven in one direction (clockwise in Figure 5B) by a drive roller. The transport path for the tape T by the tape transport unit 121 includes a section that transports the tape T vertically downward. The tape transport unit 121 feeds out the tape T in synchronization with the transport speed of the blank B by the transport mechanism 101 and transports it to the bonding point P. Therefore, at the bonding point P of the bonding unit 123, the transport speed of the tape T and the transport speed of the blank B become the same, and the amount of the blank B and the tape T transported becomes the same, so bonding can be performed while suppressing the occurrence of wrinkles and misalignment in the tape T.

[0040] The tape cutting unit 122 cuts the tape T in the tape width direction perpendicular to the tape transport direction in the tape transport path. Preferably, the tape cutting unit 122 is positioned to cut the tape T in the section of the transport path where the tape T is transported vertically downward by the tape transport unit 121. In the vertical state, tension acts on the tape T in the longitudinal direction (vertically downward) due to its own weight, which increases the rigidity of the tape T and improves the stability of the transport of the tape T, and therefore the cutting of the tape T is also stable. After cutting, the tape T is held by the tape transport belt 125 by the tape transport unit 121 and transported to the bonding unit 123.

[0041] The cutting positions for tape T are indicated by black arrows in Figure 5B. Since tape T is cut in the tape width direction by the tape cutting unit 122, the tape width of the tape roll corresponds to the width of tape T.

[0042] The bonding unit 123 cuts the tape T in the tape width direction perpendicular to the tape transport direction in the tape transport path. The bonding unit 123 has a drive roller 126, which is also the tension roller of the tape transport belt 125 of the tape transport unit 121, and a nip roller 127, which is positioned opposite to the drive roller 126 and rotates in a driven manner so as to advance in the same direction at the bonding point in synchronous motion with the drive roller 126.

[0043] In the tape bonding mechanism 120, the uncut tape T is conveyed in the longitudinal direction, the tape T is cut in the width direction, and the cut tape T is also conveyed in the longitudinal direction and supplied along the side edge F of the blank B. Since the conveying speed of the tape T is synchronized with the conveying speed of the blank B, the blank B heated by the blank heating mechanism 110 and the tape T are stacked together and sandwiched between the drive roller 126 and the nip roller 127. At the bonding point P, the left half T1 of the tape T comes into contact with the bonded edge region A1 on the surface side of the heated blank B, and the tape T can be bonded onto this bonded edge region A1 by the pressure, as the resin layer 3 of the blank B melts into a bondable state.

[0044] To explain the positional relationship between the drive roller 126 and the nip roller 127 and the thickness of the blank B and tape T, for example, the thickness of the blank B is approximately 0.4 mm, the thickness of the tape T is approximately 0.05 mm, and the gap between the drive roller 126 and the nip roller 127 is approximately 0.45 mm.

[0045] In this embodiment, the drive roller 126 and the nip roller 127 are positioned with a gap of a size corresponding to the thickness of the tape T in between.

[0046] The area to which the tape T is applied to the blank B by the tape bonding mechanism 120 is the central area of ​​the blank B, leaving the upstream and downstream ends of the blank's side edges untouched in the blank transport direction. The end areas where the tape T is not applied are, for example, areas with a length t1 in the blank transport direction of approximately 5 mm ± 1 mm. That is, the length h of the tape T cut by the tape cutting unit 122 is shorter than the length of the side edge of the blank B (for example, 110 mm) and is the length obtained by subtracting the length of the end areas where the tape T is not applied (for example, 100 mm). If the positional accuracy of the bonding is low, the end-face coating effect may not be properly achieved, the curling process during the assembly of blank B may be hindered, or the appearance may be damaged. Note that the end regions are not exposed inside the container, as they become the curled opening or the bottom during the assembly of blank B.

[0047] The specific amount of outward protrusion of the tape T relative to the adhesive edge region A1 on the surface side of the blank B varies somewhat depending on the width of the tape T, but it is sufficient that it is securely attached to both the front and back surfaces of the side edge of the blank B and that the end face E is covered. For example, it is preferably 20-80% of the width of the tape T after deducting the length of the end face E, and more preferably 50%.

[0048] The specific method for adhering the tape T to the blank B in the bonding unit 123 is not limited to a method of pressing with two rollers, but various known configurations can be adopted.

[0049] [Tape temporary fastening mechanism] The temporary tape fastening mechanism 130 is a mechanism that performs a temporary tape fastening process, welding the tape T to a portion of the adhesive end region A1 on the upstream side in the blank transport direction. As shown in Figure 6A, the temporary tape fastening mechanism 130 is positioned between the tape bonding mechanism 120 and the tape folding mechanism 140, and temporarily fastens the tape T to the surface side of the blank B, preventing the tape T from peeling off the blank B in the tape folding mechanism 140 described later, or improving the folding accuracy of the tape T.

[0050] For temporary fastening of tape T, it is sufficient for the left half T1 of tape T to be welded to at least a portion of the adhesive edge region A1 on the surface side of blank B, on the upstream side in the blank transport direction (blank tip side). That is, it is sufficient for at least the tip side of the left half T1 of tape T in the blank transport direction to be welded to the blank tip side of the adhesive edge region A1 on the surface side of blank B. For example, an area of ​​63 mm in the longitudinal direction from the tip of the left half T1 of tape T (upper end in Figure 7) and the entire width of the left half T1 of tape T (5 mm) in the width direction is welded to blank B.

[0051] Specifically, as shown in Figure 6B, the tape temporary fastening mechanism 130 includes an upper sealing bar 131 that is movable up and down and is provided on the transport path of the side end of the blank B to heat the surface side of the side end of the blank B, and a fixed lower sealing bar 136 that heats the back side of the side end of the blank B.

[0052] As shown in Figure 7, the upper sealing bar 131 and the lower sealing bar 136 each have a size corresponding to the area to be temporarily fixed in the left half T1 of the tape T (width of 5 mm, blank transport length t2 of 63 mm). By lowering the upper seal bar 131 while the blank B is stationary in a predetermined position, a predetermined area where the tape T at the side end of the blank B should be temporarily secured is sandwiched between the upper seal bar 131 and the lower seal bar 136, thereby enabling the temporary securing process. When the upper seal bar 131 is in the raised position, the space between the upper seal bar 131 and the lower seal bar 136 becomes a transport path for the side end of the blank B, allowing the blank B to pass through.

[0053] In this embodiment, the temperature of the upper seal bar 131 is, for example, 130°C, and the temperature of the lower seal bar 136 is, for example, 60°C. Since the tape T is temporarily fixed to the surface side of the side end of the blank B, it is preferable to set the temperature of the upper seal bar 131 to be higher than that of the lower seal bar 136. If the temperature of the lower seal bar 136 is excessively high, the blank B may stick to the lower seal bar 136.

[0054] In this embodiment, the surfaces of the upper seal bar 131 and lower seal bar 136 that come into contact with the blank B and tape T are subjected to surface treatment such as fluororesin processing, in addition to temperature control, to prevent the resin layers of the blank B and tape T from adhering to the upper seal bar 131 and lower seal bar 136.

[0055] The specific method for welding the tape T to the blank B in the temporary tape fastening mechanism 130 is not limited to a method using a sealing bar (heating plate), but can employ various known configurations as long as the tape T can be temporarily fastened to the blank B.

[0056] [Tape folding mechanism] The tape folding mechanism 140 is a mechanism that performs a tape folding process in which the remaining portion of the tape T (hereinafter referred to as the "right half") T2 protruding from the side edge F on the front side of the blank B is folded back to the back side (the other side) along the side edge F of the blank B. As shown in Figure 8, the tape folding mechanism 140 has an insertion passage 141 that extends in the blank transport direction, which allows the blank B to pass through the side edge of the blank B while the blank B is being transported.

[0057] The insertion passage 141 is open on one side (the front side in Figure 8) along the blank transport direction, allowing the side end of the blank B to pass through during transport. The insertion passage 141 has a ceiling wall 142 positioned opposite the surface side (upper side in Figure 8) of the plane on which the transported blank extends (hereinafter referred to as the "blank plane") of the blank B, a return wall 143 whose angle with respect to the blank plane continuously decreases as the blank B is transported in the blank transport direction, and a back wall 144 that connects the ceiling wall 142 and the return wall 143. That is, the return wall 143 has different slopes depending on its position along the blank transport direction, and the slope state of the wall surface changes continuously or stepwise as it moves in the blank transport direction.

[0058] The inner surface of the insertion passage 141 of the tape folding mechanism 140 according to this embodiment, that is, the surface that comes into contact with the blank B and the tape T, is treated with a surface treatment such as fluororesin processing from the viewpoint of non-adhesion and low friction with the blank B and the tape T.

[0059] By passing a blank B, with its left half T1 of tape T attached to its surface and its right half T2 protruding from its side edge F, through the insertion passage 141, the tape T interferes with the back wall 144 and the folded wall 143, causing the right half T2 of tape T to automatically bend toward the back side of blank B. Finally, it is bent 180° so that it is in close proximity to and facing the back side of blank B.

[0060] To explain in more detail, Figure 9(a) shows a cross-section of the insertion passage 141 at a position 2 mm away from the entrance A in the blank transport direction. At this position, the ceiling wall 142 is not located close by, and the return wall 143 is formed integrally with the back wall 144 as a flat plate and is angled with the ceiling wall 142. However, the return wall 143 and the back wall 144 are spaced apart so as not to come into contact with the tape T, so the tape T is not bent.

[0061] Figure 9(b) shows a cross-section of the insertion passage 141 at a position 10 mm away from the entrance A in the blank transport direction. At this position, the ceiling wall 142 is provided at a distance of, for example, 1.05 mm from the blank plane. The return wall 143 at this position is integrally flat with the back wall 144, with a horizontal distance of 0.68 mm from the end face E of the blank B and a slope of 114° with respect to the blank plane. The tape T is bent once according to the back wall 144 and the return wall 143.

[0062] Figure 9(c) shows a cross-section of the insertion passage 141 at a position 20 mm away from the entrance A in the blank transport direction. At this position, the ceiling wall 142 is provided very close to the blank plane (distance d1 = 0.05 mm), and the folding wall 143 at this position is integrally flat with the back wall 144, with a horizontal distance of 0.2 mm from the end face E of the blank B and a slope of 104° with respect to the blank plane. The tape T is further bent according to the back wall 144 and the folding wall 143.

[0063] Figure 9(d) shows a cross-section of the insertion passage 141 located 30 mm away from the entrance A in the blank transport direction. At this location, the ceiling wall 142 is positioned in the same location as in Figure 9(c), and the folding wall 143 at this location is integrally flat with the back wall 144, with a horizontal distance d2 of 0.2 mm from the end face E of the blank B and a slope of 90° with respect to the blank plane. The tape T is further bent according to the back wall 144 and the folding wall 143.

[0064] Figure 9(e) shows a cross-section of the insertion passage 141 located 40 mm away from the entrance A in the blank transport direction. At this location, the ceiling wall 142 is positioned in the same location as in Figure 9(c). The back wall 144 at this location has a horizontal distance of 0.2 mm from the end face E of the blank B, an angle of 90° with respect to the blank plane, and a vertical length (vertical length in Figure 9) of 0.6 mm. The folding wall 143 is continuous with the back wall 144 and has a slope of 68° with respect to the blank plane. The tape T is folded once along the back wall 144 and then folded again along the folding wall 143.

[0065] Figure 9(f) shows a cross-section of the insertion passage 141 at a position 50 mm away from the entrance A in the blank transport direction. At this position, the ceiling wall 142 is located in the same position as in Figure 9(c), and the back wall 144 is located in the same position as in Figure 9(e). The folding wall 143 is continuous with the back wall 144 and has a slope of 37° with respect to the blank plane. The tape T is further bent according to the folding wall 143.

[0066] Figure 9(g) shows a cross-section of the insertion passage 141 located 60 mm away from the entrance A in the blank transport direction. At this location, the ceiling wall 142 is located in the same position as in Figure 9(c), and the back wall 144 is located in the same position as in Figure 9(e). The folding wall 143 is continuous with the back wall 144 and has a slope of 9.5° with respect to the blank plane. The tape T is further bent according to the folding wall 143.

[0067] Figure 9(h) shows a cross-section of the insertion passage 141 at a position 68 mm away from the entrance A in the blank transport direction. At this position, the ceiling wall 142 is located in the same position as in Figure 9(c), and the back wall 144 is located in the same position as in Figure 9(e). The folding wall 143 is continuous with the back wall 144 and has a slope of 0° with respect to the blank plane. The tape T is bent further according to the folding wall 143, resulting in a state where the left half T1 of the tape T attached to the surface side of the blank B is bent by nearly 180°.

[0068] In the tape folding mechanism 140, the right half T2 of the tape T to be folded is bent along the back wall 144 and the folding wall 143. As a result, the tape T, folded along the back wall 144 which is slightly separated from the end face E of the blank B, is folded without contacting the end face E of the side end of the blank B.

[0069] In this state, the tape T is welded, and the resulting end-faced blank B has a small space formed between the end face E of the blank B and the tape T. Here, "not in contact with the end face E of the blank B" means that a space can be formed between the end face E and the folded tape T, and that the length of the tape T from the front side edge to the back side edge of the blank B is greater than the length of the end face E in the thickness direction (i.e., the thickness of the blank B), including the case where a part of the floating tape T is in contact with the end face E.

[0070] In the end-face-treated blank B obtained using the tape end-face processing device 100 according to this embodiment, for example, the width of the left half T1 of the tape T that is welded to the adhesive end region A1 on the surface side of the side end of the blank B is 4.7 mm, the width of the remaining right half T2 that is welded to the adhesive end region A2 on the back side is 4.7 mm, and the width of the non-welded portion facing the end face E is 0.6 mm. As described above, the space formed between the end face E of the end-faced blank B and the tape T obtained in the tape end-face processing device 100 according to this embodiment is a minute space, but this is not essential, and the device may be configured to form a larger space.

[0071] In the tape folding mechanism 140 according to this embodiment, the folding of the tape T is achieved by a single insertion passage 141 in which the internal wall structure is continuously changed. However, the specific configuration of the tape folding mechanism 140 is not limited to the above embodiment. It may also be configured to gradually fold the tape using multiple stations, or to fold the tape while the blank B is stopped rather than while it is being transported.

[0072] [First welded part] The tape application end processing device 100 of this embodiment has a welding mechanism for attaching the folded tape T to the adhesive end region A2 on the back surface of the blank B. This welding mechanism consists of a first welding section 150 that temporarily fastens the folded tape T to the adhesive end region A2 on the back surface of the blank B, and a second welding section 160 that welds the entire surface of the folded tape T to the adhesive end region A2 on the back surface of the blank B.

[0073] The first welding section 150 performs a first welding step in which it temporarily fastens the folded tape T to the adhesive end region A2 on the other side of the blank B. Specifically, the first welding section 150 is located near the exit of the insertion passage 141 of the tape folding mechanism 140, and temporarily fastens the folded tape T to the back side of the blank B, maintaining the folded state of the tape T and providing it to the second welding section 160. For temporary fastening of tape T to the back side of blank B, it is sufficient for a portion of the right half T2 of tape T to be welded to the area within the width direction (left-right direction in Figure 10B) perpendicular to the blank transport direction in the adhesive edge region A2 on the back side of blank B. For example, a 2.2 mm wide area from the free end of tape T folded back on the back side of blank B (the right end before folding) and extending from the leading end to the trailing end in the blank transport direction is welded to the adhesive edge region A2 on the back side of blank B.

[0074] More specifically, the first welding section 150 includes a tape straightening guide 155 that supports the area of ​​the tape T other than the temporary fastening area on the back side of the blank B, as shown in Figures 10A and 10B, and maintains a folded state in which the tape T folded by the tape folding mechanism 140 is forced to come close to the other side of the blank B. The first welding section 150 further includes a fixed upper seal bar 151 that heats the front side of the side end of the blank B and is provided on the transport path of the side end of the blank B, and a vertically movable lower seal bar 156 that heats the back side of the side end of the blank B.

[0075] The tape straightening guide 155 consists of a non-heated bar that supports the tape T in an upward direction from below, facing the upper sealing bar 151. The lower sealing bar 156 is positioned adjacent to the tape straightening guide 155 and facing the upper sealing bar 151. The tape straightening guide 155 and the lower sealing bar 156 are separated by, for example, about 0.5 mm in the horizontal direction.

[0076] In Figure 10B, the area indicated by fine diagonal lines within the upper sealing bar 151 represents the portion opposite to the left half T1 of the tape T (size: widthwise length 4.7 mm, blank transport direction length 100 mm), and the area indicated by fine diagonal lines within the lower sealing bar 156 represents the portion opposite to the area of ​​the right half T2 of the tape T that should be temporarily secured (size: widthwise length 2.2 mm, blank transport direction length 100 mm).

[0077] The tape straightening guide 155 is fixedly installed, and the space between the exit of the insertion passage 141 of the tape folding mechanism 140 and the upper seal bar 151 in the first welding section 150 and the tape straightening guide 155 is substantially continuous, so that the blank B can be transported to a predetermined heating point while maintaining the folded state of the tape T. Since the tape correction guide 155 is made of a non-heated bar, the tape T is prevented from coming into contact with the sealing bar for extended periods, thereby suppressing thermal shrinkage of the tape T.

[0078] In this embodiment, the surfaces of the tape straightening guide 155 that come into contact with the blank B and the tape T are treated with a surface treatment such as fluororesin processing to prevent the resin layers of the blank B and the tape T from adhering to the tape straightening guide 155.

[0079] By raising the lower seal bar 156 while the blank B is stationary in a predetermined position, the side end of the blank B is sandwiched between the upper seal bar 151 and the lower seal bar 156, thereby enabling temporary fastening. After temporary fastening, the free end of the right half T2 of the tape T is welded to the back surface of the blank B, while the remaining right half T2 of the tape T is left floating without being welded to the blank B. On the other hand, when the lower seal bar 156 is in the lowered position, the space between the upper seal bar 151, the lower seal bar 156 and the tape straightening guide 155 becomes a transport path for the side end of the blank B, allowing the blank B to pass through.

[0080] In this embodiment, the temperature of the upper seal bar 151 is, for example, 115°C, and the temperature of the lower seal bar 156 is, for example, 135°C. This is because the tape T is temporarily fixed to the back side of the side end of the blank B, and because time has passed since the blank B was heated by the blank heating mechanism 110. Therefore, it is preferable to set the temperature of the lower seal bar 156 to be higher than the temperature of the upper seal bar 151.

[0081] On the other hand, the upper seal bar 151 does not need to be heated as much as the lower seal bar 156 because it retains the heat applied by the tape temporary fastening mechanism 130. If the temperatures of the upper seal bar 151 and the lower seal bar 156 are excessively high, the tape T may stick to the upper seal bar 151 or the lower seal bar 156.

[0082] In this embodiment, the surfaces of the upper seal bar 151 and lower seal bar 156 that come into contact with the blank B and tape T are subjected to surface treatment such as fluororesin processing, in addition to temperature control, to prevent the resin layers of the blank B and tape T from adhering to the upper seal bar 151 and lower seal bar 156.

[0083] The specific method for welding the tape T to the blank B in the first welding section 150 is not limited to a method using a sealing bar (heating plate), as long as the tape T can be temporarily fixed to the blank B. Various known configurations can be adopted.

[0084] [Second weld part] The second welding section 160 performs a second welding process in which the entire surface of the folded tape T is welded. In other words, the second welding section 160 welds almost the entire surface of the folded tape T to the adhesive end region A2 on the back surface of the blank B. Since a portion of the right half T2 of the tape is temporarily fixed to the back surface of the blank B at the first welding section 150, the folded state of the tape T is maintained even without correction by the tape correction guide.

[0085] In this embodiment, the welding of the tape T at the second welding portion 160 is performed on the entire surface of the right half T2 of the tape T facing the back side of the blank B, but it is not limited to this. It is sufficient if any floating areas of the tape T that have not been welded to the back side of the blank B at the first welding portion 150 are newly welded, and if it is melted during the heat sealing process when assembling the blank B to form a paper container, some floating may remain.

[0086] Specifically, as shown in Figures 11A and 11B, the second welding section 160 includes a fixed upper sealing bar 161 that heats the surface side of the blank B's side end and is provided on the transport path of the blank B's side end, and a vertically movable lower sealing bar 166 that heats the back side of the blank B's side end.

[0087] In Figure 11B, the areas indicated by fine diagonal lines within the upper seal bar 161 and the lower seal bar 166 represent the portions of the tape T that are to be welded (size: widthwise length 4.7 mm, blank transport direction length 100 mm) on the left half T1 and the right half T2.

[0088] By raising the lower seal bar 166 while the blank B is stationary in a predetermined position, the side end of the blank B is sandwiched between the upper seal bar 161 and the lower seal bar 166. This allows for full-surface welding. After full-surface welding, the left half T1 of the tape T is welded to the surface of the blank B, and most of the right half T2 is welded to the back surface of the blank B, so that the tape T is attached to both the front and back surfaces of the blank B by welding. As a result, the end face E is covered. Note that the end face E of the blank B may be directly welded with the tape T, or it may be covered by the tape T through a gap.

[0089] When the lower seal bar 166 is in the lowered position, the space between the upper seal bar 161 and the lower seal bar 166 becomes a conveying path for the side end of the blank B, allowing the blank B to pass through.

[0090] In this embodiment, the temperature of the upper seal bar 161 is, for example, 40°C, and the temperature of the lower seal bar 166 is, for example, 130°C. Since the tape T is welded to the unwelded portion of the adhesive edge region A2 on the back side of the blank B, it is preferable to set the temperature of the lower seal bar 166 to be higher than the temperature of the upper seal bar 161.

[0091] On the other hand, the upper seal bar 161 does not need to be heated as much as the lower seal bar 166 because it retains the heat applied in the previous process. If the temperatures of the upper seal bar 161 and the lower seal bar 166 are excessively high, the tape T may stick to the upper seal bar 161 or the lower seal bar 166.

[0092] In this embodiment, the surfaces of the upper seal bar 161 and lower seal bar 166 that come into contact with the blank B and tape T are subjected to surface treatment such as fluororesin processing, in addition to temperature control, to prevent the resin layers of the blank B and tape T from adhering to the upper seal bar 161 and lower seal bar 166.

[0093] The specific method for welding the tape T to the blank B in the second welding section 160 is not limited to a method using a sealing bar (heating plate), as long as the tape T can be temporarily fixed to the blank B. Various known configurations can be adopted. For example, a pressing method using a fixing roller or an ultrasonic method may be used. Furthermore, depending on the welding method adopted, the welding can be performed while the blank B is being transported, rather than while the blank B is stalled during transport.

[0094] The tape T described above exhibits excellent conformability to bending during the end-face processing of the blank B. Furthermore, the tape T suppresses the occurrence of wrinkles during end-face processing. Therefore, when applying tape T to the end face of the blank B, the occurrence of adhesion defects can be significantly reduced. Accordingly, tape T is suitable for end-face processing that covers the end face of a blank.

[0095] The embodiments of the present invention have been described above, but these are merely examples, and various other configurations can also be adopted.

[0096] In the embodiment described above, Figure 1(b) shows an example in which resin layers 3, 3, which are water-sealing layers, are formed on both sides of the base paper 2 with respect to the blank B. However, the resin layer 3, which is a water-sealing layer, may be formed on only one side of the base paper 2. [Examples]

[0097] The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited thereto.

[0098] (Example 1) We prepared tapes with the following specifications and performed the following evaluations. Layer composition: PE (polyethylene, 20 μm thick) / PET (polyethylene terephthalate, 12 μm thick) / PE (polyethylene, 20 μm thick) Tape width: 10mm (Example 2) We prepared tapes with the following specifications and performed the following evaluations. Layer composition: PE (thickness 34 μm) / Al (thickness 8 μm) / PET (thickness 12 μm) Tape width: 10mm (Comparative Example 1) We prepared tapes with the following specifications and performed the following evaluations. Layer composition: PE single layer (thickness 10 μm) Tape width: 10mm (Example 3) We prepared tapes with the following specifications and performed the following evaluations. Layer composition: PE single layer (thickness 25 μm) Tape width: 10mm (Example 4) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE single layer (thickness 30 μm) Tape width: 10mm (Example 5) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE single layer (thickness 40 μm) Tape width: 10mm (Example 6) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE (thickness 46μm) / Ny (nylon, thickness 13μm) / PE (thickness 46μm) Tape width: 10mm (Example 7) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE (thickness 55μm) / Ny (nylon, thickness 15μm) / PE (thickness 55μm) Tape width: 10mm (Example 8) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE (thickness 75μm) / Ny (nylon, thickness 20μm) / PE (thickness 75μm) Tape width: 10mm (Example 9) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE (thickness 88μm) / Ny (nylon, thickness 24μm) / PE (thickness 88μm) Tape width: 10mm (Comparative Example 2) We prepared a base paper with the following specifications and performed the following evaluations. Layer composition: PE (thickness 154μm) / Ny (nylon, thickness 42μm) / PE (thickness 154μm) Tape width: 10mm

[0099] (Loop stiffness) For each example and comparative example, the tape (processed from the original paper to the tape width and loop length dimensions described below) was measured for loop stiffness under the following conditions. The measured loop stiffness values ​​are shown in Table 1. (Loop stiffness measurement conditions) Device: LOOP STIFFNESS TESTER DA type (manufactured by Toyo Seiki Co., Ltd.) Tape width: 10mm Loop length: 70mm Speed: 3.3mm / sec Indentation amount: 10mm Measurement environment: Temperature 23°C, relative humidity 50%

[0100] (Deadhold ability) For each example and comparative example, the tape was folded in half so that the longitudinal center line became the crease, the crease was smoothed by hand, and then the crease was pressed down by hand at room temperature. Immediately after releasing the hand, the folded state was visually checked. The dead hold performance was evaluated according to the following criteria. A: If the folded state was maintained for more than 1 second C: If the folded state was in the process of returning to the original state in less than 1 second. The results obtained regarding deadhold performance are shown in Table 1. When the deadhold performance is "A", the tape can maintain its folded shape without returning after passing through the tool in the end-face processing device, and the end-face processing of the blank can be performed stably.

[0101] (Folded edge processing) The tapes for each embodiment and comparative example were attached to one side of a blank, creating a state similar to that after passing through the tape temporary fastening mechanism 130 shown in Figure 6A. The state of the tapes after passing through the blank with the tapes attached to it, as shown in Figure 6A, was evaluated according to the following criteria. A: The folded state (good folding process) C: Due to bending or other reasons, the material does not fold properly (folding process defect).

[0102] [Table 1]

[0103] The tape of this disclosure is suitable for use in processing the end faces of blanks that constitute paper containers and is useful in the manufacture of paper containers. [Explanation of Symbols]

[0104] 1 Paper laminate, 2 Base paper, 3 Resin layer, 100 Tape application end processing device, 101 Conveying mechanism, 102 Conveying lane, 110 Blank heating mechanism, 111, 116 Heating section, 112, 117 Hot air outlet, 120 Tape bonding mechanism, 121 Tape conveying unit, 122 Tape cutting unit, 123 Bonding unit, 125 Tape conveying belt, 126 Drive roller, 127 Nip roller, 130 Tape temporary fastening mechanism, 131 Upper seal bar, 136 Lower seal bar, 140 Tape folding mechanism, 141 Insertion passage, 142 Ceiling wall, 143 Folding wall, 144 Back wall, 150 First welding section, 151 Upper seal bar, 155 Tape straightening guide, 156 Lower seal bar, 160 Second welding section, 161 Upper seal bar, 166 Lower seal bar, B blank, E end face T, tape T1 left half, T2 right half, A1 adhesive end area, A2 adhesive end area, F side edge, P bonding point

Claims

1. A tape used for processing the end faces of blanks used as the body of paper containers, having a thermoplastic resin on its surface, The layer thickness of the aforementioned tape is 25 to 200 μm. In the end-face processing described above, the tape is positioned so that the longitudinal direction of the tape coincides with the longitudinal direction of the end face of the blank, and the tape is folded back so that the approximate center of the longitudinal direction of the tape becomes a fold, and is attached to one side and the other side of the blank so as to cover the end face of the blank.

2. The tape according to claim 1, wherein the layer configuration of the tape is one selected from the group consisting of a laminate in which polyethylene, polyethylene terephthalate, and polyethylene are laminated in that order, a laminate in which polyethylene, aluminum foil, and polyethylene are laminated in that order, a laminate in which polyethylene, nylon, and polyethylene are laminated in that order, and a single layer of polyethylene.

3. The tape according to claim 1, wherein the loop stiffness measured under the following conditions is 0.5 to 100 mN. (Loop stiffness measurement conditions) Device: LOOP STIFFNESS TESTER DA type (manufactured by Toyo Seiki Co., Ltd.) Tape width: 10 mm Loop length: 70 mm Speed: 3.3mm / sec Indentation amount: 10 mm Measurement environment: Temperature 23°C, relative humidity 50%

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