JPS62246716A - Horn and anvil of apparatus for super-sonic sealing - Google Patents

Abstract

PURPOSE:To secure the transmission of super-sonic oscillation to a welding sheet and to make the welding film, by making a plane where the horn and the anvil of the super-sonic oscillator contact the welding sheet into a specific shape. CONSTITUTION:The side faces of convex parts 5, 5 provided at planes 3, 3 where the horn 1 and the anvil 2 of a super-sonic oscillator contact a welding sheet are inclined at theta deg. and become inclined slopes 6. By making the convex parts 5, 5 into trapezoid forms by providing such inclined slopes 6, when multi- layered sheets are welded each other it becomes easier for the convex parts 5 to bite into the above-mentioned sheet. It is possible for the convex parts 5 to bite the multi-layered sheet to the inside layer which becomes a welding surface side in each layer, and super-sonic oscillation can be certainly transmitted to be welding surface.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an ultrasonic sealing device, and more particularly to an uneven pattern to be engraved on the contact surface of a horn and an duck that clamps a sheet-like object that is a sole object with the sheet-like object. . [Prior art and its problems] Ultrasonic sealing devices that weld a pair of sheet-like objects together using ultrasonic vibrations include: ■ So-called longitudinal vibration type devices that apply ultrasonic vibrations in a direction perpendicular to the welding surface; ■The so-called transverse vibration type, which applies ultrasonic vibration in a direction parallel to the welding surface.
No. (Japanese Unexamined Patent Publication No. 58-33424) and patent application No. 1987-87
No. 765 (Japanese Unexamined Patent Publication No. 58-205723) proposed,
There are three types of diagonal vibration types that apply ultrasonic vibration in an oblique direction to the welding surface. Looking at the characteristics of each of these three types, ■The longitudinal vibration type applies vibration in a direction perpendicular to the welding surface, so there is so-called side-slip between the horn and anvil and the sheet material to be welded. No phenomenon occurs, therefore,
There is essentially no need to carve an uneven pattern on the contact surface of the pawn or anvil that comes into contact with the sheet-like object. However, since vibration is applied in a direction perpendicular to the welding surface, even if there is foreign matter attached to the welding surface, it is impossible to prevent it from flying laterally due to the vibration.
Therefore, it is not suitable for welding the bottom of a duplex container containing cosmetics or the like. ■Next, the lateral vibration type has the ability to prevent foreign matter attached to the welding surface from being blown away in the horizontal direction by vibration, but since it applies vibration in a direction parallel to the welding surface, the pawn and anvil A side-slipping phenomenon occurs between the sheet and the sheet material held by them, and the vibration is not efficiently transmitted to the welding surface, causing the pawn to generate heat, or the frictional heat due to vibration is not generated sufficiently, resulting in welding. There are problems in that defects occur, unpleasant high-pitched sounds are generated due to sideslip, and hangnails or scrapes occur on the surface of the sheet-like material that is in contact with the horn or anvil. Therefore, a concavo-convex pattern as shown in FIG. 12 is engraved on the contact surface of the horn and anvil with the sheet-like material, but very good results have not been obtained with the concave-convex pattern shown in FIG. ■Finally, the diagonal vibration type has the advantages of both the vertical vibration type and the horizontal vibration type because the vibration is dispersed in the vertical and horizontal directions, and it does not blow away foreign objects attached to the welding surface in the horizontal direction. In addition to this, it also has the effect of suppressing the horizontal slip phenomenon to some extent, and can perform more efficient welding than the vertical vibration type or the horizontal vibration type. Therefore, it shows good results in welding multilayer sheets together, which is not so good with the transverse vibration type. However, the side-slip phenomenon still occurs, and this side-slip phenomenon cannot be eliminated even by carving a concave-convex pattern on the contact surface as shown in Fig. Even more efficient welding is desired. In this way, whether transverse vibration type or diagonal vibration type ultrasonic sealing devices can efficiently transmit ultrasonic vibrations is determined by the markings on the contact surfaces of the horn and anvil that hold the sheet. It depends on what kind of uneven pattern you want to create, but in that case, be careful to leave as much contact surface parallel to the welding surface on the horn or anvil as possible in order to efficiently generate frictional heat on the welding surface. The purpose is to ensure that the concave and convex patterns formed on the pawns and anvils bite into the pawn and anvil to eliminate side slipping. The case where the contact surface parallel to the welding surface is maximum is when no uneven pattern is provided, but in this case, the degree of side slip is also maximum as described above. On the other hand, the case where the penetration of the uneven pattern is maximized is when the tip of the convex part is made sharp, but in this case, there is no contact surface parallel to the welding surface, so ultrasonic vibrations are transmitted to the welding surface. It is difficult to generate frictional heat. Considering the uneven pattern shown in FIG.
Since the convex portion 5 is formed with a rectangular planar shape, and the side surface of the convex portion 5 is a vertical surface 21, it is difficult for the convex portion 5 to bite into the sheet-like object, making it impossible to reliably suppress side slipping. . In addition, as another conventional example, Utility Model Application Publication No. 60-201928

[FIGS. 13(a), (b), and (c)] is a superstructure in which a plurality of uneven lines 22 are cut along the longitudinal direction of the contact surface at a constant depth and protruding height. A horn 1 for sonic sealing is described, and specifically, it is described that the uneven streak 22 is a continuous uneven surface having no corners in a sine wave shape in the transverse cross section of the contact surface 3. However, it is clear from Fig. 13(a) that the ultrasonic sealing device described in this publication is of the longitudinal vibration type (the vibration direction of the ultrasonic wave is the axial direction of the horn; Since there is a contact surface at the tip, it is understood that vibration is applied in a direction perpendicular to the welding surface of the sheet),
Therefore, an uneven pattern to prevent side slipping is essentially unnecessary, and the reason why the uneven stripes 22 are provided is that the resin melted by ultrasonic vibration is held in a flowing position by the uneven stripes 22 at the sealing part. However, their purpose is different as they aim to increase welding ability. Even if this structure is used in a transverse vibration type or diagonal vibration type device, since the cross section of the concavo-convex stripes 22 is sinusoidal, there is no contact surface 3 parallel to the welding surface, and the frictional heat is sufficiently absorbed. In addition, the uneven streaks 22 that have dug in have little effect in suppressing lateral slip. Against this background, the inventors of the present invention etched various uneven patterns on the contact surfaces of horns and anvils and repeated experiments. In order to ensure that the convex part bites into the sheet-like object, it is necessary to maximize the contact surface parallel to the welding surface, that is, without providing the convex part [Fig. 11(a)], and to In other words, the tip of the convex part is sharpened.

[Figure 11(b)] Intermediate state with -'I-

[Fig. 11(C)] was found to be the most effective method. The present invention has been made against this background, and provides an ultrasonic sealing device by improving the uneven pattern to be carved on the contact surface of a horn and anvil that clamps a sheet-like object to the sheet-like object. The technical problem is to ensure that ultrasonic vibrations are efficiently transmitted to sheet-like objects so that welding can be performed reliably and firmly. [Means for Solving the Problems] In order to solve the above-mentioned technical problem, the present invention includes a horn 1 and an anvil 2 that sandwich a pair of sheet-like objects, and uses frictional heat generated by ultrasonic vibration to separate the pair of sheet-like objects. The following technical measures were taken in an ultrasonic sealing device for welding sheets together. Note that the ultrasonic sealing device in this case is limited to a transverse vibration type or an oblique vibration type, as a logical premise for the purpose of the present invention. The gist of the present invention is to form a plurality of convex portions 5 whose upper surfaces are flat by forming grooves 4 on each contact surface 3 of the horn 1 and anvil 2 that abuts the pair of sheet-like materials, and to form a plurality of convex portions 5 whose upper surfaces are flat. The side surface of the convex portion 5 is formed into an inclined surface 6 so that the cross section of the convex portion 5 is trapezoidal. Here, the inclination angle θ of the inclined surface 6 needs to be changed somewhat depending on the sheet material to be welded, but generally it is 5 to 4.
5 degrees, preferably 10 to 30 degrees. Further, the grooves 4 for forming the plurality of convex portions 5 may be straight grooves 4 and then carved so as to intersect with each other, or grooves 4 may be carved so as to form a curved pattern that is not straight. In the former case, the rectangular or triangular convex portions 5 are formed in a continuous pattern as shown in FIGS. Or, as shown in Fig. 9, a hexagonal convex portion 5
are repeated alternately, and the hexagonal (honeycomb) convex portion 5
For example, a pattern in which circular convex portions 5 are repeated (FIG. 1) or a pattern in which circular convex portions 5 are repeated (FIG. 1θ) can be exemplified. The size of the pattern formed by these grooves 4 and convex portions 5 is determined by taking into consideration the factors of generating more frictional heat, shortening the sealing time, and minimizing the pressing force by the pawn 1 and the anvil 2. Distance Q from one end of one convex part 5 to one end of another convex part 5 adjacent to it (pattern pitch)
is 0.5 to 2.0 mm. Preferably, the size is 0.8 to 1.6 mm. Note that the shape and size of the protrusion 5 on the pawn 1 side may be different from the shape and size of the protrusion 5 on the anvil 2 side. Furthermore, in order to obtain sufficient frictional heat, it is necessary to leave a certain amount of flat surface parallel to the welding surface. The ratio is 30+70 to 64:3
B, preferably around 40:60. In addition, if the groove 4 for forming the convex part 5 is too deep, the convex part 5 will dig into the sheet too deeply, such as when welding thermoplastic resin sheets together, and the thickness of the welded part will become thinner, resulting in tearing. In addition, the volume of the groove 4 may become too large and a large amount of molten resin may enter the groove.
If they solidify, the appearance of the sealed portion will deteriorate. On the other hand, if the groove 4 is too shallow, the amount of bite of the convex portion 5 will be small, making it insufficient to suppress the side-slip phenomenon, and the efficiency of generating frictional heat at the welding surface will deteriorate. Therefore, the depth of the groove 4 is 3 times the thickness of one of the pair of sheets to be welded.
5-65%, preferably 40-60% is preferred. By the way, the depths of the grooves 4 on the pawn I side and the grooves 4 on the anvil 2 side do not need to be the same, and one may be deeper than the other. By the way, the pair of sheet-like objects to be welded by the ultrasonic sealing device of the present invention is a single-layer sheet of thermoplastic resin, a multi-layer sheet of thermoplastic resin, or a thermoplastic resin layer and a material other than synthetic resin, such as paper or aluminum. It can be used for welding the bottom of a tube container containing cosmetics, toothpaste, etc., for example. Regarding the case where a multilayer sheet is used for a tube container, the multilayer sheet of thermoplastic resin is a multilayer tube whose inner layer is high density polyethylene (HDPE) and outer layer is low density polyethylene (LDPE), A multilayer tube with a gas barrier resin layer such as EVAL or nylon between high-density polyethylene and low-density polyethylene.A multilayer sheet with sheet layers made of different materials is a multilayer tube with an aluminum laminate layer in the middle layer, etc. is fried. [Function] According to the present invention, since the side surface of the convex portion 5 provided on the contact surface 3 of the horn 1 and the anvil 2 is formed into an inclined surface 6, it is easy to bite into a sheet-like object. In particular, when welding multilayer sheets together, the protrusions 5 tend to dig into each other, so by appropriately selecting the height of the protrusions 5, that is, the depth of the grooves 4,
As shown in FIG. 4(b), the convex portion 5 can penetrate into the inner layer of each layer of the multilayer sheet, which is the welding surface side, and the ultrasonic vibration can be reliably transmitted to the welding surface. Therefore, frictional heat can be generated efficiently. In this respect, if the convex part 5 bites only into the outer layer, the ultrasonic vibrations will not be transmitted directly to the inner layer, but will be transmitted through the outer layer, and will be attenuated when transmitted from the outer layer to the inner layer. Therefore, sufficient frictional heat is not generated. In particular, when welding the bottom of a multilayer tube that has polyethylene layers as the inner and outer layers and an EVAL layer as the middle layer, the polyethylene layer and the EVAL layer are not bonded together due to the nature of the resin, so the convex part extends to the inner polyethylene layer. Welding was difficult with conventional means in which the protrusions 5 do not cut into the inner layer, but according to the present invention, the protrusions 5 cut into the inner layer, so welding can be performed satisfactorily. Further, by forming the inclined surface 6, the cross section of the groove 4B body also becomes trapezoidal, and the sheet-like material that has bitten into the groove 4 is likely to be peeled off from the pattern surface after welding. When the grooves 4 for forming the convex portions 5 are not straight but have a curved pattern, the resin melted by ultrasonic vibration is evenly distributed over the welding surface along the grooves 4. Therefore, there is no unevenness in the welding of the pair of sheet-like materials, and the welding can be performed reliably and firmly. This effect is most remarkable when the planar shape of the convex portion 5 formed by the curved pattern of grooves 4 is a honeycomb. In this regard, if the groove 4 is straight, the molten resin will flow in one direction only, and there will be parts with too little molten resin and parts with too much molten resin on the welding surface, resulting in uneven welding, and in the worst case, parts that will not be welded. may occur. Furthermore, in order to obtain sufficient frictional heat, it is necessary to leave some flat surface parallel to the welding surface, but in the case of the present invention, the upper surface of the convex portion 5 is left as a flat surface, so this problem is solved. None. In addition, in the case of an oblique vibration type ultrasonic sealing device, ultrasonic vibration is applied from an oblique direction, and even when welding the bottom of a tube container, for example, even if there is a filler attached to the welding surface, the ultrasonic vibration is applied to the outside of the welding surface. As mentioned above, it is possible to scatter the filler, but if the convex portion 5 whose side surface is an inclined surface 6 is provided on the contact surface 3 of the horn 1 or the anvil 2 as in the present invention,
Since there is little side slipping, the action of scattering the filler to the outside of the welding surface is more effective. Therefore, welding can be performed even when the cosmetic is attached to the welding surface, and furthermore, welding can be performed even when the dupe container is filled with cosmetic solution and sealed with the cosmetic solution still attached to the welding surface. [Examples and Comparative Examples] First, the oblique vibration type ultrasonic sealing device and the transverse vibration type ultrasonic sealing device used in the Examples and Comparative Examples will be described. As shown in Fig. 3, the oblique vibration type ultrasonic sealing device
A support arm 12 is rotatably connected to the tip of the support rod 11, and an ultrasonic oscillator 13, an amplifier 14, and a horn l are attached to this support arm 12, arranged on the same axis. It is oscillated in the axial direction. The horn 1 has a pair of contact surfaces 3 on both sides of the tip, and each contact surface 3 has an angle ψ of 2 with respect to the axis of the horn 1.
It is inclined so that it is 0 degrees, and the contact surface 3 has a first
The honeycomb-shaped convex portion 5 shown in the figure is formed by repeated turns. The angle θ of the side surface of the convex portion 5 is also set to an angle of 20 degrees. In addition, the pitch Q of 7 turns is 1.1 mm, and the ratio of the groove 4 to the plane on the convex part is 4.
1:51, and the depth of the groove 4 is 0.2■. When one contact surface 3 of the tip of the horn l is fixed upright, the axis connecting the ultrasonic oscillator 13, the amplifier 14, and the horn l is supported at an angle of 20 degrees with respect to this upright contact surface 3. The arm 12 is now fixed, and thus the position of the horn I is fixed. Then, facing the contact surface 3 of the tip of the upright horn l,
An anvil 2 is installed, and a contact surface 3 is formed on the opposite surface of the anvil 2 on the horn L side, and this contact surface 3 is also formed with a honeycomb-shaped convex portion 5 shown in FIG. This convex portion 5
The standard is the same as that of the convex portion 5 on the horn L side. This anvil 2 is moved to the horn 1 by a hydraulic cylinder (not shown).
It is provided so as to be able to move forward and backward toward the side, and in its retracted position, the contact surface 3 of the tip of the horn 1 and the contact surface 3 of the anvil 2 are set apart by 10 mm. As shown in FIG. 4(a), when the anvil 2 is retracted, the bottom of the tube container 17, which has a circular cross section and is conveyed while being held by the holder 16 on the belt conveyor 15, is flattened and horned. 1 and anvil 2 is provided adjacent to horn 1 and anvil 2, and this guide 18 has a pair of opposing tapered surfaces 19, 19 to flatten tube container 17. have. The bottom of the tube container 17 that has entered between the horn 1 and the anvil 2 is pressed between the contact surface 3 of the tip of the pawn 1 and the contact surface 3 of the anvil 2 as the anvil 2 advances, and is welded by ultrasonic vibration. . Since this ultrasonic vibration is applied at an angle of 20 degrees to the welding surface at the bottom of the tube container 17, it is dispersed in a direction perpendicular to the welding surface and in a direction parallel to the welding surface. Next, in the transverse vibration type ultrasonic sealing device, as shown in FIGS. 5 and 6, the axis connecting the ultrasonic oscillator 13, amplifier 14, and horn 1 is fixed upright, and A pair of parallel contact surfaces 3 are provided on both sides of the tip of the horn 1, and other points are the same as the oblique vibration type ultrasonic sealing device. In this case, ultrasonic vibrations vibrating in the axial direction of the horn I are applied to the welding surface of the tube container 17 in a parallel direction via the contact surface 3. Hereinafter, the bottoms of tube containers 17 made of various materials were sealed using the diagonal vibration type and transverse vibration type ultrasonic sealing devices, and the seal strength was measured. The results are shown in Table 1. The uneven patterns formed on the contact surfaces 3 of the horn 1 and the anvil 2 are a honeycomb pattern shown in FIG. 1 and a conventional square pattern shown in FIG. 12. Table 1 (Sealability) ◎: Very good ○: Good X,: LDP with problems
E...Low density polyethylene MDPE...Medium density polyethylene HDPR...High density polyethylene
PP... Polypropylene AL... Aluminum Ultrasonic frequency: 20&Hz Output 1.8&W <thickness of each layer> LDPE single layer...360 (μm) MDPE
Single layer...400 (μs LDPE/nylon/PP...170/60/1
7G (μN) LDPR/HDPE...150/
300 (μm) LDPE/EVAL/MDPE
...170/60/170 (μ1) LDPE/
LDPE/AL/PE/LDPE...250/90/
12/12/80 (μm) LDPR/AL/LDPE/
Paper DPE...200/12/90/20/80 (μ
Scrap) LDPE/LDPE...380/380(μ
m) As is clear from Table 1, the one in which the honeycomb-shaped convex portion 5 is provided on the contact surface 3 seals better than the conventional one, especially when combined with an oblique vibration type ultrasonic sealing device. Very good results can be obtained in some cases. Since the side surface of the convex portion 5 is an inclined surface 6, it has good biting, and the unpleasant friction noise generated during sealing is small.
Further, the sheet-like material after sealing was easily removed from the pattern surface. Since the combination of the oblique vibration type ultrasonic sealing device and the 7% nicum-shaped convex portion 5 is good as described above, experimental data for this combination is shown in Table 2. The seal strength was measured using a tension compression tester at a pressurizing speed of 100 mm/win and pressurizing surface conditions: φ60xm. As is clear from Table 2, the combination of the oblique vibration type ultrasonic sealing device and the honeycomb convex portion 5 requires a short welding time and has high sealing strength. [Effects of the Invention] According to the present invention, since the side surface of the convex portion provided on the contact surface between the horn and the anvil is made into an inclined surface, it is easy to bite into a sheet-like object, and therefore, the side-slip phenomenon can be suppressed as much as possible, and the Sonic vibrations can be reliably transmitted to the welding surface, efficiently generating frictional heat, and making welding reliable and strong. Therefore, it is now possible to successfully weld multilayer sheets, which was conventionally considered impossible by ultrasonic welding, and it is particularly effective in welding multilayer sheets having EVAL in the middle layer. Furthermore, since the ultrasonic vibrations are transmitted reliably, the horn generates less heat, and the horn does not require much cooling, allowing for speedy and continuous welding. Furthermore, since the side-slip phenomenon is reduced, the unpleasant sealing noise generated during welding can be reduced, and the working environment can be improved. In addition, since the side-slip phenomenon is eliminated, there are no hangnails or scrapes on the surface of the sheet material held between the horn and the anvil, and a beautiful finish can be achieved. In addition, since the cross section of the convex part is trapezoidal, the sticking phenomenon of sheet-like objects is greatly reduced, and sheet-like objects that have dug into the grooves can be easily peeled off from the pattern surface after welding, and no cuts occur in the sheet-like objects. . From the above, whereas in the past it was necessary to prepare sealing devices suitable for various materials such as heat seals, high frequency seals, and ultrasonic seals, by using the horn and anvil of the present invention, A single ultrasonic sealing device can seal various materials, weld firmly and reliably, and the appearance of the welded portion can be made extremely beautiful. By the way, the conventional ultrasonic sealing device for welding the bottom of a tube container is equipped with a clamping device 20 called a jaw (JaW) as shown in FIGS. 14 and 15 in order to ensure welding. Previously, the vicinity of the welded part at the bottom of the tube container was clamped with a horn and an anvil before welding was performed.However, according to the present invention, the welding is reliable and strong. This eliminates the need for additional auxiliary equipment, and thus the device can be simplified.

[Brief explanation of drawings]

1(a) and (b) are a plan view and a sectional view showing an example of the uneven pattern according to the present invention, FIG. 2 is a front view of the horn and anvil portion of the oblique vibration type ultrasonic sealing device, and FIG. A front view of the oblique vibration type ultrasonic sealing device, FIG. 4(a) is a process diagram showing the process of sealing the bottom of a tube container, FIG.
Figure (b) is a sectional view showing the state of the convex part biting in, Figure 5 is a front view of the transverse vibration type ultrasonic sealing device, Figure 6 is a front view of its horn and anvil portion, and Figures 7 to 1O. 11 is a plan view showing another example of the uneven pattern, FIG. 11 is a cross-sectional view showing the process leading to the invention, FIGS. 12(a) and 12(b) are a plan view and a sectional view showing the conventional uneven pattern, and FIG. 13 (a) (b)
(c) is a diagram showing another conventional example of a horn and its contact surface, No. 14.
The figure is a front view showing a conventional oblique vibration type ultrasonic sealing device.
FIG. 15 is a sectional view showing the jaw portion. 1... Horn, 2... Anvil, 3... Contact surface,
4... Groove, 5... Convex portion, 6... Inclined surface. Figure 1 (b) Figure 4 (b) Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (10)

[Claims] (1) The pair of sheet-like objects are held in the horn and anvil of an ultrasonic sealing device that welds the pair of sheet-like objects together using frictional heat generated by ultrasonic vibration. At this time, a plurality of convex portions with flat upper surfaces are formed by forming grooves on each contact surface that abuts on the pair of sheet-like materials, and the side surfaces of the convex portions are shaped so that the cross section of the convex portions is trapezoidal. A horn and anvil of an ultrasonic sealing device characterized by having an inclined surface. (2) The horn and anvil of an ultrasonic sealing device according to claim 1, wherein the grooves for forming the plurality of convex portions form a bent pattern. (3) The horn and anvil of an ultrasonic sealing device according to claim 1, wherein the vibration direction of the ultrasonic waves is oblique to the welding surfaces of the pair of sheet materials. (4) The ultrasonic sealing device horn and anvil according to claim 1, wherein the vibration direction of the ultrasonic waves is parallel to the welding surfaces of the pair of sheet materials. (5) The horn and anvil of an ultrasonic sealing device according to claim 1, wherein the pair of sheet-like materials are single-layer sheets of thermoplastic resin. (6) The horn and anvil of an ultrasonic sealing device according to claim 1, wherein the pair of sheet-like materials are multilayer sheets of thermoplastic resin. (7) The ultrasonic sealing device horn and anvil according to claim 2, wherein the planar shape of each convex portion formed by the groove is a honeycomb shape. (8) The ultrasonic sealing device horn and anvil according to claim 2, wherein each convex portion formed by the groove has an octagonal planar shape. (9) The ultrasonic sealing device horn and anvil according to claim 2, wherein each convex portion formed by the groove has a circular planar shape. (10) The horn and anvil of an ultrasonic sealing device according to claim 6, wherein the multilayer sheet includes a sheet layer made of a thermoplastic resin and a different material.