Heat sealing blades for horizontal sealing rolls, horizontal sealing rolls, and packaging machines

Abstract

To provide a heat seal blade for a horizontal seal roll, a horizontal seal roll including the heat seal blade, and a filling machine including the horizontal seal roll, and specifically to suppress generation of resin accumulation at a part where a longitudinal seal portion and a horizontal seal portion intersect and generation of a constricted portion in the horizontal seal portion.SOLUTION: A heat seal blade for a horizontal seal roll forms a horizontal seal portion on a cylindrical film by the cylindrical film that is attached to extend in an axial direction of each of peripheral surfaces of one pair of horizontal seal rolls, and that is formed by folding one packaging film at a center portion or overlapping two packaging films to form a longitudinal seal portion on at least overlapping side edge part, being held between the pair of opposing horizontal seal rolls. At least one of the heat seal blade of the pair of the horizontal seal rolls is chamfered at a corner portion on a side of a rearward end portion in a rotation direction that is at least in contact with the longitudinal seal portion.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a heat seal blade for a horizontal seal roll for applying a horizontal seal to a packaging film, a horizontal seal roll provided with one or a plurality of the heat seal blades at intervals in the circumferential direction on the circumferential surface, and a packaging machine using the horizontal seal roll as a horizontal seal device.

Background Art

[0002] In recent years, it has been widely and commonly practiced to automatically fill and package liquid substances, viscous substances, or powders, granular substances, and other packaged goods such as food and drink, seasoning liquids, pharmaceuticals, and cosmetics with a soft packaging film.

[0003] In such a filling and packaging machine for packaged goods, for example, as described in Patent Document 1, a packaging film having a laminated structure is folded in two in the width direction so that the sealant layers face each other, and the folded and overlapping side end portions are heated and pressed by a pair of vertical seal rolls to be fused to each other while being fed downward to form a vertical seal portion extending in the longitudinal direction and made into a cylindrical shape. Then, the packaged goods are filled into the cylindrical packaging film, and a horizontal seal portion is formed by heating and pressing the packaged goods over the entire width of the cylindrical packaging film while squeezing them with a pair of horizontal seal rolls (heat seal blades). Thus, it is disclosed that packaging bags are continuously manufactured.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Thus, in conventional filling and packaging machines, a cylindrical packaging film is held between a pair of opposing horizontal sealing rolls (heat sealing blades), and the packaged material is squeezed out as the horizontal sealing rolls rotate while heating and pressurizing the film. As a result, during horizontal sealing, the molten sealant layer of the packaging film flows, causing clumps of the sealant layer (hereinafter referred to as "resin pools") to form within the horizontally sealed area, or causing thinner areas (hereinafter referred to as "constrictions") to form near the resin pools due to the movement of the sealant layer.

[0006] In particular, at the rear end of the heat sealing blade in the direction of rotation, the surface pressure is high, and the packaging film at the sealing position is already heated due to its proximity to the heat sealing blade, making the sealant layer prone to flow. Furthermore, at the point where it intersects with the vertical sealing section, the sealant layer of the vertical sealing section, which has been heated by the vertical sealing roll, is heated and pressurized again by the horizontal sealing roll, making it easy for resin to accumulate. As a result, the inside and outside of the packaging bag can become conductive in a tunnel-like manner, causing liquid leakage, or the seal strength of the horizontal sealing section decreases due to the formation of constrictions, leading to bag rupture. Therefore, resin accumulation was prevented by appropriately changing the horizontal sealing conditions, but if the horizontal sealing conditions were determined to match the point where it intersects with the vertical sealing section, the seal strength of other parts would decrease, making the adjustment difficult.

[0007] Therefore, the present invention relates to a heat sealing blade for a horizontal sealing roll for forming a horizontal sealing portion in a direction perpendicular to the vertical sealing portion on a tubular film formed by forming a vertical sealing portion on the side edges of overlapping packaging films, a horizontal sealing roll equipped with the heat sealing blade, and a filling machine equipped with the horizontal sealing roll, with a particular aim to suppress the occurrence of resin accumulation at the intersection of the vertical sealing portion and the occurrence of constriction within the horizontal sealing portion. [Means for solving the problem]

[0008] To solve the above problems, the present invention provides a heat sealing blade for a transverse seal roll, which is attached to the circumferential surface of a pair of transverse seal rolls that are positioned close to each other, parallel to each other and rotated in opposite directions, so as to extend in the axial direction of each of them, and which is used to sandwich a tubular film formed by folding one packaging film in the middle so that the adhesive or sealant layers face each other, or by overlapping two packaging films so that the adhesive or sealant layers face each other, and forming a vertical seal portion at least on the overlapping side edges, between the pair of opposing transverse seal rolls to form a transverse seal portion on the tubular film, wherein the heat sealing blade is attached to the circumferential surface of a pair of transverse seal rolls so as to extend in the axial direction of each of them, and which is used to sandwich a tubular film formed by folding one packaging film in the middle so that the adhesive or sealant layers face each other, or by overlapping two packaging films so that the adhesive or sealant layers face each other, and forming a vertical seal portion at least on the overlapping side edges, between the pair of opposing transverse seal rolls to form a transverse seal portion on the tubular film, wherein at least one of the heat sealing blades of the pair of transverse seal rolls teeth , the rear end in the direction of rotation Regarding, The corner on the side that contacts the aforementioned vertical sealing portion is surface Processed The angle of the chamfered corner is 30 to 70° with respect to the rear end of the heat sealing blade in the direction of rotation. We propose a heat sealing blade for horizontal sealing rolls, characterized by the following features.

[0009] Furthermore, the present invention proposes a transverse seal roll in which multiple heat sealing blades for transverse seal rolls are provided on the circumferential surface of the transverse seal roll, extending in the axial direction of the transverse seal roll, either one or spaced apart from each other in the circumferential direction.

[0010] Furthermore, the present invention relates to a packaging machine comprising: a vertical sealing device for forming a tubular film by folding one packaging film in the middle so that the adhesive layer or sealant layer faces each other, or by overlapping two packaging films so that the adhesive layer or sealant layer faces each other, and forming a vertical sealing portion at least on the overlapping side edges; and a horizontal sealing device for sandwiching the tubular film between a pair of horizontal sealing rolls that are positioned close together and parallel to each other and rotated in opposite directions, thereby forming a horizontal sealing portion on the tubular film and partitioning the space for filling the packaged goods inside, wherein each of the pair of horizontal sealing rolls has, on its circumferential surface, one or a plurality of heat sealing blades that extend in the axial direction of the horizontal sealing roll and sandwich the tubular film to form the horizontal sealing portion, and at least one of the heat sealing blades of the pair of horizontal sealing rolls teeth, the rear end in the direction of rotation Regarding, The corner on the side that contacts the aforementioned vertical seal portion is chamfered. The angle of the chamfered corner is 30 to 70° with respect to the rear end of the heat sealing blade in the direction of rotation. We propose a packaging machine characterized by the following features.

[0011] Furthermore, in this invention 、 (1 The heat sealing blade is provided such that the intersection of the beveled corner and the rear end of the heat sealing blade in the direction of rotation is located on the vertical sealing portion when heat sealing is performed. ( 2 The vertical seal portion comprises a knurled seal portion having a mesh-like seal pattern located on the side edge of the overlapping packaging film, and a solid seal portion without a seal pattern located on the filling space side of the packaged product, wherein the intersection is positioned between the widthwise center of the solid seal portion and the side edge of the filling space. This would be a more preferable solution. [Effects of the Invention]

[0012] According to the present invention, by chamfering at least the corner on the side of the rear end of the heat sealing blade provided on the circumferential surface of the horizontal sealing roll that contacts the vertical sealing portion, the amount of heat and surface pressure applied to the lower horizontal sealing portion, which forms the bottom of the packaging bag, at the point where it intersects with the vertical sealing portion is reduced, thereby effectively suppressing the occurrence of resin accumulation at that point, and effectively preventing liquid leakage due to the sealing area becoming conductive in a tunnel-like manner, as well as the occurrence of constrictions within the horizontal sealing portion. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows one embodiment of the packaging machine according to this invention. [Figure 2] This is a perspective view showing one embodiment of a pair of horizontal sealing rolls equipped with a heat sealing blade for horizontal sealing rolls according to the present invention. [Figure 3] This is a plan view showing one embodiment of the heat sealing blade according to the present invention. [Figure 4] It is a schematic diagram showing the heat seal position of the tubular film by the heat seal blade of FIG. 3. [Figure 5] It is a diagram showing the cross-sectional observation position of the lower side horizontal seal portion in the embodiment. [Figure 6] It is a cross-sectional photograph of each condition at the cross-sectional observation position of FIG. 5.

Mode for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the present invention will be described based on what is shown in the drawings. FIG. 1 is a schematic diagram showing the configuration of a vertical filling and packaging machine as an example of the packaging machine of the present invention, FIG. 2 is a perspective view showing an embodiment of a pair of horizontal seal rolls provided with a heat seal blade for a horizontal seal roll of the present invention, and FIG. 3 is a plan view showing an embodiment of the heat seal blade of the present invention. Note that the packaging machine of the present invention is not limited to a vertical filling and packaging machine, and can be various packaging machines such as a vertical pillow packaging machine, a horizontal pillow packaging machine, and a multi-column packaging machine.

[0015] The vertical filling and packaging machine in Figure 1 runs a long packaging film 10, which is made of a laminated film consisting of a base film layer made of, for example, a biaxially oriented ethylene-vinyl alcohol copolymer resin and a sealant layer made of, for example, an unstretched ethylene-vinyl acetate copolymer resin, along its longitudinal direction. At the film folding section 20, the film is folded back in the width direction so that the sealant layers face each other, overlapping both side edges. These side edges are then continuously sealed longitudinally in the longitudinal direction by a vertical sealing device 21 consisting of a pair of vertical sealing rolls to form a vertical sealed section 11, and the packaging film 10 is formed into a tubular shape to form a tubular film 12. Next, the packaged material M is continuously filled into the tubular film 12 from the filling nozzle 22, and a lateral sealing device 23 having a pair of lateral sealing rolls 30a and 30b squeezes out the packaged material M, forming a lateral sealing portion 13 across the entire width of the tubular film 12. Then, the lateral sealing portion 13 is cooled by a cooling unit 24 having a similar pair of lateral sealing rolls to fix the seal, thereby enabling the production of numerous packaging bags P while automatically filling the filling space 14 of each packaging bag P with the packaged material M consisting of liquid, viscous, or gel-like fluid substances such as food, beverages, seasonings, pharmaceuticals, cosmetics, etc. The packaging bags P produced in this manner are then cut at the center of the running direction of the packaging film 10 (tubular film 12) by a cutting unit 25 (upper lateral sealing portion 13', lower lateral sealing portion 13''), and shipped as single or multi-packs. In this embodiment, a single long piece of packaging film 10 is folded back at the center in the width direction, and the overlapping side edges are vertically sealed by a vertical sealing device 21 to form a tube. However, two long pieces of packaging film may be overlapped, and the overlapping edges of both sides may be vertically sealed by vertical sealing devices to form a tube.

[0016] FIG. 2 is a perspective view showing an enlarged view of the horizontal sealing device 23. The horizontal sealing device 23 has a pair of horizontal sealing rolls 30a and 30b that are arranged in parallel close to each other and are rotationally driven in opposite directions. On the circumferential surfaces of each of the horizontal sealing rolls 30a and 30b, a plurality of heat-sealing blades 31 are provided at equal intervals in the circumferential direction and extending along the axis thereof. The horizontal sealing rolls 30a and 30b rotate synchronously so that the heat-sealing blades 31 provided thereon cooperate to sandwich the tubular film 12, and the facing sealant layers are fusion-bonded to each other while squeezing out the packaging M interposed in the tubular film 12 by the opposing heat-sealing blades 31 to form a horizontal seal portion 13.

[0017] FIG. 3 is a plan view showing an embodiment of the heat-sealing blade 31 having a chamfered portion 32 provided on at least one of the horizontal sealing rolls 30a and 30b. The heat-sealing blade 31 is composed of a seal plate having a rectangular shape in plan view, and a corner portion (left side in the figure) on the side that abuts against the longitudinal seal portion 11 during heat-sealing at the rear end portion in the rotational direction is chamfered to form a chamfered portion 32. In FIG. 3, the chamfered portion 32 is composed of a C-chamfered portion (chamfering to form a 45° surface), but it can be various types such as an R-chamfered portion (chamfering with a rounded edge).

[0018] When the tubular film 12 is sandwiched, heated, and pressurized by the heat-sealing blade 31 having the above configuration, the portion that abuts against the longitudinal seal portion 11 at the rear end portion in the rotational direction of the heat-sealing blade 31 is chamfered, so that the amount of heat and surface pressure applied to the portion intersecting the longitudinal seal portion 11 can be weakened, the resin of the melted sealant layer does not flow excessively, and the generation of resin accumulation at this portion and the generation of constricted portions in the horizontal seal portion 13 can be effectively suppressed. Therefore, according to the heat-sealing blade 31 of the present embodiment, since only the portion intersecting the longitudinal seal portion 11 can weaken the surface pressure and the amount of heat, there is no need to change the horizontal sealing conditions, and the seal strength of other portions does not decrease.

[0019] The chamfered portion 32 is preferably processed so that the gradient θ (the angle between the extension of the rear end 31a in the direction of rotation and the hypotenuse 32a of the chamfered portion 32) is 30 to 70°, and more preferably in the range of 45 to 60°. By keeping it within this range, the amount of heat and linear pressure applied to the portion that intersects with the vertical seal portion 11 when a horizontal seal is formed can be reduced, while ensuring high seal strength.

[0020] In this embodiment, as shown in Figure 1, one example is the formation of a three-sided sealed packaging bag P in which the vertical seal portion 11 is provided only on the overlapping side edges of the packaging film 10. Therefore, only one corner on the rear side in the rotational direction of the heat sealing blade 31 consists of a chamfered portion 32. However, when manufacturing a four-sided sealed packaging bag P (a packaging bag in which the vertical seal portion 11 is provided on both side edges), it is preferable to make both corners on the rear side in the rotational direction of the heat sealing blade 31 into chamfered portions.

[0021] Furthermore, as schematically shown in Figure 4 for the heat sealing position of the tubular film 12 by the heat sealing blade 31, the heat sealing blade 31 is positioned such that the intersection point 33 of the rear end edge 31a in the rotational direction and the slanted edge 32a of the chamfered portion 32 is located on the vertical sealing portion 11, preferably near the side edge 14a on the filling space 14 side, and more preferably within 2.0 mm of the side edge 14a on the filling space 14 side.

[0022] In particular, when the vertical seal portion 11 consists of a knurled seal portion 11a having a mesh-like seal pattern located on the side edge of the tubular film 12 as shown in Figure 4, and a solid seal portion 11b located on the side of the filling space 14 of the packaged product and without a seal pattern, the intersection 33 is positioned between the widthwise center position shown by the dashed line in the figure of the solid seal portion 11b and the side edge 14a of the filling space 14. This reduces the linear pressure applied to the packaging film 10 by the amount of the inclination distance due to the chamfered portion 32 (hypotenuse 32a) of the heat seal blade 31, thereby reducing the formation of excessive resin buildup and constrictions.

[0023] Furthermore, if the filling speed of the packaged goods M is increased, the packaging film 10 may meander depending on the material of the packaging film 10 and the amount of packaged goods M filled. For this reason, it is preferable to provide guides on the transport line for the packaging film 10 to stabilize the movement of the packaging film 10, or to provide assist rollers that pull the packaging film 10 downstream to suppress meandering of the packaging film 10. [Examples]

[0024] Using a pair of horizontal sealing rolls equipped with the heat sealing blades having the chamfered portion described in the above embodiment, a packaging bag according to the embodiment (example of the present invention) was formed, and the presence or absence of resin accumulation and constriction at the intersection of the lower horizontal sealing portion (the horizontal sealing portion formed by the rear end in the rotational direction of the heat sealing blade) and the vertical sealing portion was investigated. The chamfered portion was formed on only one of the heat sealing blades of the pair of horizontal sealing rolls, with a cutting width of 4.5 mm x 4.5 mm and a gradient θ: 45°.

[0025] Table 1 shows the bag-making conditions for the packaging bags. As a comparative example, a packaging bag formed using a conventional rectangular heat-sealing blade without a chamfered edge was used as the heat-sealing blade for the horizontal sealing roll. Furthermore, the packaging films used were of the following two types: Film 1: Nylon 15μm / PE 50μm (2-layer structure) Film 2: PET 12μm / Al-deposited PET 12μm / PE 40μm (3-layer structure)

[0026] [Table 1]

[0027] <Fault observation results> Figure 6 shows the results of observing the cross-section of the packaging bags of the present invention example and the comparative example at the point where the lower horizontal seal intersects with the vertical seal (see Figure 5). From the results in Figure 6, although some bulging was observed in the present invention example, no significant difference in thickness was seen. In contrast, in the comparative example, there were areas where the cross-section was significantly bulging, and areas where the thickness was thinner near these bulging areas, indicating the occurrence of resin accumulation and constriction.

[0028] <Thickness measurement results> Table 2 shows the results of measuring the thickness at the thinnest point (constriction) from the tomographic image in Figure 6. From the results in Table 2, it was found that in all of the examples of the present invention, the thickness at the constriction was thick, and the chamfered portion prevented the occurrence of resin accumulation at the intersection with the vertical seal portion.

[0029] [Table 2] [Industrial applicability]

[0030] Although the above embodiment shows the manufacture of a three-side sealed packaging bag, the present invention is not limited to three-side sealed packaging bags, but can be applied to the manufacture of various types of packaging bags, such as four-side sealed and back-sealed packaging bags. Furthermore, the heat sealing blade, horizontal sealing roll, and packaging machine of the present invention can be widely used not only for packaging bags but also for the manufacture of various containers and the like using packaging film. [Explanation of Symbols]

[0031] P packaging bag M Packaged item 10 Packaging film 11 Vertical seal section 11a Knurled seal section 11b Solid seal section 12. Cylindrical film 13 Side seal section 13' Upper side seal 13'' Lower side seal section 14 Filling space 14a Side edge 20 Film fold section 21 Vertical sealing device 22 Filling nozzles 23 Lateral sealing device 24 Cooling section 25 Cut section 30a, 30b Horizontal sealing roll 31 Heat sealing blades 31a Edge 32 Chamfered section 32a hypotenuse 33 intersection

Claims

1. A pair of transverse seal rolls are positioned in close proximity and parallel to each other, facing each other, and rotated in opposite directions. These are mounted on the circumferential surfaces of each roll so as to extend in the axial direction of the rolls. A heat sealing blade for a horizontal sealing roll, which forms a tubular film by folding one packaging film in the middle so that the adhesive layer or sealant layer faces the other, or by overlapping two packaging films so that the adhesive layer or sealant layer faces the other, and forming a vertical seal portion at least on the overlapping side edges, and then sandwiching the tubular film between a pair of opposing horizontal sealing rolls to form a horizontal seal portion on the tubular film, A heat sealing blade for a horizontal sealing roll, characterized in that at least one of the pair of horizontal sealing rolls has a chamfered edge on the side that contacts the vertical sealing portion, only on the rear end in the direction of rotation, and the gradient of the chamfered edge is 30 to 70° with respect to the rear end of the heat sealing blade in the direction of rotation.

2. A transverse seal roll having one or more heat-sealing blades for transverse seal rolls as described in claim 1, provided on its circumferential surface so as to extend in the axial direction thereof.

3. A vertical sealing device that forms a tubular film by folding one packaging film in the middle so that the adhesive layer or sealant layer faces each other, or by overlapping two packaging films so that the adhesive layer or sealant layer faces each other, and forming a vertical seal portion at least on the overlapping side edges, A packaging machine comprising a lateral sealing device that sandwiches the tubular film between a pair of lateral sealing rolls, which are positioned close together, parallel to each other, and rotated in opposite directions, thereby forming a lateral sealing portion on the tubular film and partitioning the space for filling the packaged material inside, The packaging machine is characterized in that each of the pair of transverse sealing rolls has, on its circumferential surface, one heat sealing blade extending in the axial direction of the transverse sealing roll and clamping the tubular film to form the transverse sealing portion, or a plurality of heat sealing blades spaced apart from each other in the circumferential direction, and at least one of the heat sealing blades of the pair of transverse sealing rolls has a chamfered corner on the side that contacts the longitudinal sealing portion only at the rear end in the direction of rotation, and the gradient of the chamfered corner is 30 to 70° with respect to the rear end of the heat sealing blade in the direction of rotation.

4. The packaging machine according to claim 3, characterized in that the heat sealing blade is provided such that the intersection of the beveled corner and the rear end of the heat sealing blade in the direction of rotation is located on the vertical sealing portion when heat sealing is performed.

5. The packaging machine according to claim 4, wherein the vertical sealing portion comprises a knurled sealing portion having a mesh-like sealing pattern located on the side edge of the overlapping packaging film, and a solid sealing portion without a sealing pattern located on the filling space side of the packaged product, and the intersection is provided to be located between the widthwise center of the solid sealing portion and the side edge of the filling space.

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