JP2010070252A - Continuous thermal fusion bonding/cutting device of shrink film for battery wrapping - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a continuous thermal fusion bonding/cutting device of a shrink film for battery wrapping, which stabilizes a continuous thermal fusion bonding/cutting process of a superposition part of a shrink film for shrink packaging, and heat-seals the shrink film without lowering the strength of a thermal fusion bonding part even if continuous thermal fusion bonding/cutting is executed at high speed. <P>SOLUTION: The device for continuously heat-sealing and cutting the superposition part of the shrink film includes: an ultrasonic wave oscillator 31; an anvil 4 which has an endless-track protrusion 4a for guiding the shrink film while keeping a contact with the shrink film continuously fed, and is driven in a rotating manner so that the endless-track protrusion moves in synchronization with the shrink film continuously fed; and a horn 3 which has a flat head end 3a pressed against the superposition part of the shrink film moving while keeping a contact with the protrusion of the anvil, and applies ultrasonic waves emitted from the ultrasonic wave oscillator on the superposition part of the shrink film via the flat head end. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ultrasonic horn shape and an anvil of a shrink packaging, which is a method for shipping and packaging a battery, in the continuous heat-sealing cutting of a superposed portion of a shrink film using an ultrasonic welding machine. Concerning shape.

  In the conventional shrink wrapping, the continuous heat fusion cutting of the overlapping part of the shrink film uses the ultrasonic welding machine to simultaneously fuse and cut the film, and the shape of the anvil and the ultrasonic horn at that time are respectively As shown in FIGS. 8 and 9, the anvil 104 has a cylindrical shape with a flat peripheral surface, and the ultrasonic horn has a tapered shape having an arc-shaped flat surface at the tip.

Such an anvil and ultrasonic horn are described in, for example, Patent Document 1 and Patent Document 2. Moreover, the technique of ultrasonic-sealing melt | fusion of a shrink film is described in patent documents 3-5.
JP 2000-141490 A Japanese Patent Laid-Open No. 9-278022 JP 2003-267439 A JP-A-4-253621 JP-A-8-2552

  Recently, under the influence of global environmental problems, the use of vinyl chloride as a shrink film material for packaging has been restricted, and polyethylene terephthalate (PET) resin has been adopted as an alternative material. .

  However, if a PET resin film is continuously heat-sealed at a high speed using a conventional heat-sealing cutting device, the fusion strength at the heat-sealed part becomes unstable, and the product with insufficient strength at the fusion part (not good) Non-defective products) frequently occur, resulting in a problem that the manufacturing yield decreases.

  FIG. 10 shows a cross section of a heat-sealed portion of a PET resin film heat-sealed using a conventional apparatus. A fusion nugget 6 is formed on the outside of the shrink film F1 that has been removed from the overlap-welded portion. As a result, a discontinuous shape is formed, and a fused portion having a weak joint strength is formed. The cutting process is performed simultaneously with the fusion by vibration and pressure of an ultrasonic horn, and is separated into the product-side film F1 and the collection-side film F2 at the cutting unit 7 at the center of the fusion-bonding part, and the collection-side film F2 is separated. Is wound on a winding recovery reel (not shown).

  The present invention has been made in order to solve the above-described problems, and stabilizes the continuous heat-sealing cutting process of the overlapping portion of the shrink film in the shrink wrapping so that the fusion can be performed even if continuous heat-sealing cutting is performed at a high speed. It is an object of the present invention to provide a continuous thermal fusion cutting apparatus for shrink film for battery packaging, in which the shrink film is thermally fused without reducing the fusion strength of the part.

  The continuous heat-sealing cutting apparatus for shrink film for battery packaging according to the present invention is a method for heat-sealing in parallel with the battery row so as to sandwich the battery row from above and below while feeding a plurality of batteries side by side. Shrink for battery packaging, in which continuous shrink film is fed, ultrasonic waves are applied to the superposed portion of the shrink film, and the superposed portion of the shrink film is continuously heat-sealed and cut. A continuous heat fusion cutting apparatus for a film, comprising an endless track-like convex portion that guides the shrink film while maintaining contact between an ultrasonic oscillator and the shrink film that is continuously fed, and the endless track Shrink that moves while maintaining contact between the anvil that is rotationally driven so that the convex portion moves in synchronization with the continuously fed shrink film and the convex portion of the anvil A horn that has a flat tip that is pressed against the overlap portion of the ink film, and that applies ultrasonic waves oscillated from the ultrasonic oscillator through the flat tip to the overlap portion of the shrink film; It is characterized by comprising.

  ADVANTAGE OF THE INVENTION According to this invention, the continuous heat-fusion cutting process of the overlapping part of the shrink film in shrink packaging can be stabilized. Further, according to the present invention, even when continuous thermal fusion cutting is performed at a high speed, the shrink film is thermally fused at a sufficient strength level without reducing the fusion strength of the fused portion. be able to.

  In the continuous heat-sealing cutting apparatus for shrink film for battery packaging of the present invention, the tip portion of the horn is made flat and a convex portion is formed on the anvil so that the anvil and the horn sandwich the film overlap portion. When pressure is applied and ultrasonic waves are applied, ultrasonic energy propagates in the order of horn → film overlap part → anvil in a state suitable for melting, deformation, and solidification of the PET resin film, as shown in FIG. 6A becomes a favorable shape which continues to the overlap-fused portion. Thus, in the overlap fusion part heat-sealed using the apparatus of the present invention, since the fusion nugget 6A is formed without detaching from the overlap fusion part, the entire overlap fusion part is smooth. Sufficient joint strength is obtained that is continuous and does not break easily. On the other hand, the overlap-fused portion that has been heat-sealed using a conventional apparatus is formed outside the shrink film F1 in which the fusion nugget 6 is removed from the overlap-fused portion as shown in FIG. It becomes a discontinuous shape as a whole, its fusion strength is low, and it is easy to break.

  In the present invention, the taper angle θ of the anvil convex portion is preferably 80 ° or more and 160 ° or less. If the taper angle θ is less than 80 °, the energy density of the ultrasonic energy that flows into the anvil convex portion through the film overlapping portion becomes excessive, and the film may melt excessively, resulting in a poor shape of the fusion nugget. This is because, in extreme cases, there is a risk of tearing holes in the film. On the other hand, when the taper angle θ exceeds 160 °, the concentration of ultrasonic energy is lowered, and the film is liable to be insufficiently melted, so that the necessary fusion strength may not be obtained. The taper angle θ of the anvil convex portion is more preferably 90 ° or more and 150 ° or less. In Examples 3 and 6 in Table 1 in which the taper angle θ is 90 °, good tensile strength (breaking strength) is obtained. In Examples 1 and 4 in Table 1 where the taper angle θ is 150 °, good tensile strength (breaking strength) is also obtained.

  In this invention, it is preferable to have a flat surface of 0.20 mm or more and 0.30 mm or less in the front-end | tip part of an anvil convex part. In Examples 1 to 3 in Table 1 in which the flat width of the front end portion of the anvil convex portion is 0.25 mm (dimensional tolerance ± 0.05 mm), very high tensile strength (breaking strength) is obtained. On the other hand, in this invention, the front-end | tip part of an anvil convex part is sharp, and it can also be made not to have a flat surface in this front-end | tip part substantially. Good tensile strength (breaking strength) is also obtained in Examples 4 to 6 in Table 1 in which the tip of the anvil convex portion is sharpened.

  In the present invention, a polyethylene terephthalate resin film having a thickness of 15 μm or more and 35 μm or less can be used as the shrink film to be processed. This is because a PET resin film having a thickness of less than 15 μm may cause a tear hole, and if the horn pressure is set low so that the tear hole does not occur, the necessary fusion strength cannot be obtained. On the other hand, when the thickness of the PET resin film exceeds 35 μm, it becomes difficult to ultrasonically weld the overlapped portion, and the joint strength may be insufficient. In the present invention, in addition to the PET resin, a polystyrene resin, a polyester resin, a polyvinyl chloride resin, a polyolefin resin, a polypropylene resin, and these resin films are bonded to the shrink film to be processed. A composite multilayer film or the like can be used.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments for carrying out the invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1 and FIG. 2, the continuous heat fusion cutting apparatus 1 for shrink film for battery packaging is such that the pass line of the shrink film F used for packaging of the cylindrical battery B is between the anvil 4 and the horn 3. It is arranged to pass. The pass line extends in the X-axis direction, a battery alignment feeding mechanism and a film feeding reel (not shown) are arranged on the upstream side, and a battery pack housing mechanism and a film take-up / recovery reel (not shown) are arranged on the downstream side. Each is arranged.

  The battery B to be packaged is aligned side by side in the X-axis direction so that the axis is substantially horizontal (Y-axis direction) by the battery aligning and sending mechanism upstream of the pass line, and is sent out from the mechanism. It is covered so as to be sandwiched from above and below by a film F folded in a U-turn shape fed from a film feeding reel, and in this state, it is fed out from the mechanism at a speed synchronized with the feeding speed of the film F. ing. The feeding speed of the battery B row and the shrink film F is, for example, 9 to 15 m / min. In this example, a PET resin film having a thickness of 25 μm was used as the shrink film F.

  The continuous heat-sealing cutting apparatus 1 has a structure of an upper part 2a provided with an ultrasonic horn 3 and the like above the pass line, and the pass line of the battery B / film F almost passes through the center of the height. The structure of the lower part 2b provided with the anvil 4 etc. below the line. The upper part 2a includes an ultrasonic horn 3, an ultrasonic oscillator 31, which functions as an ultrasonic welder, a vibrator 32, a dial gauge 33, and the like. The apparatus lower part 2b includes an anvil 4, an anvil drive mechanism 5, an air cylinder 41, an air cushion 42, and the like.

  The ultrasonic horn 3 is connected to an ultrasonic oscillator 31 via an ultrasonic transmission medium (not shown), and is supported by an upper air cylinder 32 so as to be movable up and down. The tip portion of the horn 3 is a completely flat flat surface 3a. The horn 3 can be made using any metal material such as carbon steel, Ti, Ti alloy, Al, Al alloy, and Monel alloy.

  The dial gauge 33 displays a gap between the horn 3 and the anvil 4. In addition, a pressure gauge (not shown) is attached. The pressure gauge is a measuring instrument for detecting and displaying the applied pressure when the horn 3 is pressed against the film F on the anvil 4 by the air cylinder 32, and sends the detected pressure signal to a process computer system (not shown). It is displayed on the monitor screen.

  The anvil 4 has a cylindrical shape as shown in FIGS. 1 to 3, and is supported so as to be rotatable around the horizontal rotation drive shaft 56 of the anvil drive mechanism 5. As shown in FIGS. 4 and 5, the anvil 4 has a tapered shape in which the profile cross-sectional shape has a narrow flat surface 4 a at the tip, and tapered surfaces 4 b on both sides. The taper angle θ of the anvil 4 is appropriately selected according to the thickness and material of the shrink film F within the range of 80 ° to 160 °. However, in the anvil having the narrow flat surface 4a at the tip, the taper angle θ is selected. Is preferably 90 °.

  The anvil 4 may be the same metal material as the ultrasonic horn 3 or may be a different metal material. Since the anvil 4 is subjected to a large amount of wear due to continuous contact with the continuously fed shrink film, a metal material having excellent wear resistance such as austenitic stainless steel or martensitic stainless steel is used. It is desirable to use it.

  The anvil drive mechanism 5 includes a motor 51, a drive pulley 52, a driven pulley 53, belts 54 and 55, and a rotation drive shaft 56. The operation of the motor 51 is controlled by a process computer (not shown) so that the peripheral speed of the anvil 4 is synchronized with the feeding speed of the battery B / film F. When the process computer starts the motor 51, the rotational force is transmitted in the order of the drive pulley 52 → the belt 54 → the driven pulley 53 → the belt 55 → the rotation drive shaft 56, and the anvil 4 is driven to rotate at a desired speed.

In the continuous heat-sealing process, the process computer controls the operation of the air cylinder 41, presses the overlapping portion of the film F with the horn 3 and the anvil 4, and applies a desired pressure to the overlapping portion of the film F. Apply. This pressing force can be switched in five stages by tap switching of the process computer according to the thickness and material of the shrink film F. The applied pressure is switched, for example, in a range where the gauge pressure of the air for driving the air cylinder (bore diameter φ25 mm) is 0.5 to 2.0 kg / cm ² . The applied pressure is adjusted by the air cushion 42.

  The cutting process is performed simultaneously with the thermal fusion by the vibration and pressurization of the ultrasonic horn 3. In the cutting process, the product-side film F1 and the collection-side film F2 are separated at the cutting unit 7 at the center of the fusion part, and the separated collection-side film F2 is placed on a winding collection reel (not shown) on the downstream side of the pass line. It is wound up.

  On the other hand, the separated product-side film F1 and the plurality of battery rows are heat-sealed and cut along the Y axis at predetermined intervals by another heat-sealing cutting device (not shown) on the downstream side of the pass line. For example, 10 batteries B become battery packs packaged with the film F1 and are accommodated in a container of a battery pack accommodation mechanism (not shown).

(Example)
Next, the fusion part of the shrink film continuously heat-sealed by the apparatus of the present invention will be described with reference to FIGS. 6 and 10 in comparison with the fusion part of the shrink film continuously heat-fused by the conventional apparatus. .

  As shown in FIG. 6, the shrink film continuously heat-sealed using the apparatus of the present invention has a fusion nugget 6 </ b> A formed at the junction where the upper and lower films F <b> 1 meet and has a high fusion strength. This is considered to be because in the apparatus of the present invention, the ultrasonic energy propagated in a state suitable for melting, deformation, and solidification of the shrink film in the order of horn → film overlapping portion → anvil. Thus, in the overlap fusion part heat-sealed using the apparatus of the present invention, since the fusion nugget 6A is formed without detaching from the overlap fusion part, the entire overlap fusion part is smooth. Sufficient joint strength was obtained that was continuous and did not break easily.

  Depending on the thickness and material of the shrink film F, in the case of a polyethylene terephthalate (PET) film having a thickness of 25 μm, the width of the flat surface at the tip of the anvil projection is 0.25 mm and the taper angle θ is 90 °. Sometimes the best results were obtained. In Examples 1 to 3, since the dimensional tolerance of the anvil projection is 0.05 mm, the width of the flat surface is substantially 0.20 to 0.30 mm.

  On the other hand, the overlap-fused portion that has been heat-sealed using a conventional apparatus is formed outside the shrink film F1 in which the fusion nugget 6 is removed from the overlap-fused portion as shown in FIG. As a whole, the shape was discontinuous and the fusion strength was low.

(Evaluation test)
The tensile breaking strength of the fused part of the shrink film F1 was measured and evaluated using the tensile tester 8 shown in FIG. In the tensile test, both ends of the films F1 of Examples 1 to 6 and the comparative example having the fusion nugget 6A or 6 are clamped with a pair of clampers 81, and the fusion nugget 6A or 6 is pulled until it breaks. The strength was measured. The results are shown in Table 1.

The front view of a shrink film continuous heat fusion cutting apparatus. The side view of a shrink film continuous heat fusion cutting apparatus. The principal part enlarged view which shows the principal part of this invention apparatus. The enlarged view which shows the anvil and horn of this invention apparatus. The enlarged view which shows the anvil and horn of this invention apparatus. The cross-sectional schematic diagram which shows the shrink film fuse | fused using this invention apparatus. The schematic diagram for demonstrating the tension test method. The principal part enlarged view which shows the principal part of a conventional apparatus. The principal part enlarged view which shows the anvil and horn of a conventional apparatus. The cross-sectional schematic diagram which shows the shrink film fuse | fused using the conventional apparatus.

Explanation of symbols

1 ... Continuous heat fusion cutting device,
3 ... Horn, 3a ... Flat surface,
31 ... Ultrasonic oscillator (ultrasonic welding machine), 32 ... Vibrator, 33 ... Dial gauge,
4 ... anvil, 4a ... flat surface, 4b ... taper surface,
41 ... Air cylinder, 42 ... Air cushion,
5 ... anvil drive mechanism, 51 ... motor, 52 ... drive pulley, 53 ... driven pulley, 54, 55 ... belt, 56 ... rotary drive shaft,
6, 6A ... Fusion nugget, 7 ... Cutting part,
8 ... tensile tester, 81 ... clamper,
B: Battery, F, F1, F2 ... Shrink film.

Claims (5)

While supplying a plurality of batteries side by side, a thermal fusion shrink film is continuously fed in parallel with the battery rows so as to sandwich the battery rows from above and below, and the shrink film to be fed A continuous heat-sealing cutting device for a shrink film for battery packaging that applies ultrasonic waves to the overlapping portion, continuously heat-bonds and cuts the overlapping portion of the shrink film,
An ultrasonic oscillator,
It has an endless track-like convex portion that guides the shrink film while maintaining contact with the continuously fed shrink film, and the endless track-like convex portion is synchronized with the continuously fed shrink film. An anvil that is rotationally driven to move;
It has a flat tip that is pressed against the overlapping portion of the shrink film that moves while maintaining contact with the convex portion of the anvil, and the ultrasonic wave oscillated from the ultrasonic oscillator through the flat tip A horn applied to the overlapping portion of the shrink film;
A continuous heat fusion cutting apparatus for shrink film for battery packaging, comprising: The apparatus according to claim 1, wherein a taper angle θ of the convex portion of the anvil is not less than 80 ° and not more than 160 °. The apparatus according to claim 1, wherein the convex part of the anvil has a flat surface of 0.20 mm or more and 0.30 mm or less at a tip part. 3. The apparatus according to claim 1, wherein the convex portion of the anvil has a pointed tip portion and substantially does not have a flat surface at the tip portion. The apparatus according to claim 1, wherein the shrink film is made of polyethylene terephthalate having a thickness of 15 μm to 35 μm.

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