WO2016207903A1

WO2016207903A1 - Ultrasonic sealing device and related methods thereof

Info

Publication number: WO2016207903A1
Application number: PCT/IN2015/000321
Authority: WO
Inventors: Kumar Rout DHIREN
Original assignee: B & A Packaging India Limited
Priority date: 2015-06-20
Filing date: 2015-08-13
Publication date: 2016-12-29
Also published as: IN2015KO00684A

Abstract

This invention relates to an ultrasonic sealing device and in particular, this invention relates to an ultrasonic sealing device having a sonotrode which applies the ultrasonic vibration and an anvil as a passive counterpart. More particularly, this present invention relates to the ultrasonic sealing device wherein the high frequently oscillating electrical field is converted into a mechanical oscillation. Furthermore, this invention also relates to an ultrasonic sealing device which has the beneficial effects of having saving manpower, safety and reliability.

Description

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Field of the Invention

This invention relates to an uitrasonic sealing device and in particular, this invention relates to an ultrasonic sealing device having a sonotrode which applies the ultrasonic vibration and an anvil as a passive counterpart. More particularly, this present invention relates to the ultrasonic sealing device wherein the high frequently oscillating electrical field is converted into a mechanical oscillation. Furthermore, this invention also relates to an ultrasonic sealing device which has the beneficial effects of having saving manpower, safety and reliability.

Background of the invention and the Related Prior Art

In ultrasound technology which covers many fields, in particular in laboratory and processing technology, so-called ultrasonic disintegrators or ultrasonic homogenisators have been applied for decades, with chiefly longitudinally functioning, rod-like ultrasonic sonotrodes which are driven via an active ultrasonic system, function according to the longitudinal oscillation mode, mostly have a length η*λ/2 and apply a reproducible ultrasonic power via their end-faces.

This tried and tested technology permits the introduction of very high ultrasonic amplitudes into fluids or pasty media via the end-face of the sonotrodes, often with the help of so-called amplitude transformers (boosters). As rule, the amplitude transformation is effected at the cost of a reduction of the cross-section of the mostly circular end-face or irradiation surface. If one assumes that the transverse dimensions— for example the sonotrode diameter— usually lies below λ/4-material waveiength, one may assume approximately equal ultrasonic amplitudes (deflection and phase) at the end-face of the sonotrode. This ensures an exact and reproducible operation, for example in analysis, since the deflection of the sonotrode is always effected in a very uniform manner over the whole end-face, has approximately equal amplitude values and effects caused by the ultrasound may be linked to this parameter.

As a rule, sonotrodes and tips of such sonotrodes consist of very oscillation resistant and simultaneously low-loss materials such as titanium for example. Special ceramic

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The patent document CN1187220 states that an ultrasonic sealing apparatus with an elongated arm having a flat heat sealing surface, and the opposing jaw, the sealing surface coating with the packaging material of the heating pressing arm of the action face of the opposing jaw, the sealing zones in contact with a liquid side of the adjacent area, the molten resin has a reservoir tank, in the action face of the opposing jaw, the sealing zones of the cutting side of the adjacent regions with the molten resin reservoir tank and the molten resin flows from the sealed zone to the cutting the inclined side. The laminated packaging material comprises a thermoplastic resin is formed into a tubular, the lower surface of the tubular packaging material to the transverse ultrasonic sealing, can fruit pulp and other inclusions together with the molten thermoplastic resin discharged from the sealing area, to achieve a good seal. The other document CN 1434764 discloses to Seal welding for at least two laminations ultrasound device, said apparatus comprising a seal welded components are made up of two elements, the two elements are a cutting board and an ultrasonic welding poles , which are disposed to face each other, so that they are facing surfaces is formed through a gap to be closed for welding the laminations (103), said gap having an inlet portion and an outlet portion, the sonotrode vibrating at high frequencies to emit ultrasonic waves, characterized in that, provided between the laminations for welding with said sealing assembly along a specific feeding direction (F) with respect to the closure means for generating a welding assembly relative motion, section above passage gap between its inlet section and an outlet portion decreases the seal welding assembly includes at least one member of a prominent ridge, the ridge did not enter the above passage gap and extending parallel to said overall direction of feed (F) direction. The present invention also relates to a method for the closure welding related flexible packaging member, and generating a package.

According to the document DE19651242 an anvil of an ultrasound welding unit for welding at least two material fields consisting of plastics-coated carrier material, with a sonotrode which is movable relative to the anvil, the welding surface lying at the front of the anvil body being profiled with raised and depressed regions. The object of the invention is to enable more than only two material fields or layers to be welded to one another by means of an ultrasound welding unit comprising the novel anvil. To that end, the raised regions take the form of narrow ribsa lower holder rib extending along the free lower edge of the welding surface and, at a spacing (a) above this rib and parallel thereto, a central weld rib extending over the entire width of the welding surface.

The document US4735753 describes to an artic!e of manufacture comprises a molded-plastic fitment such as one of the halves of a snap fastener molded in situ to a porous substrate such as a garment fabric. Various embodiments are described for the article, as well as dies for forming the same, and methods and a machine for making the same.

According to the invention US4265687 a method and apparatus for wrapping a tape around an article, such as a bundle of elongate items (e.g., wires), tightening the tape, bonding layers of the tightened tape together and cutting the tape is disclosed. The apparatus or tool includes a clamshell assembly having a movable jaw that closes about the article to be strapped. Thereafter, tape, drawn from a reserve loop by a motor, is guided by a channel formed in the inner periphery of an aperture defined by the clamsheli. The moving tape is spirally wrapped about the bundle of items and a latched backup foot located in the clamshell aperture. After the bundle and backup foot are encircled, by a suitable number of layers, a rack moves a plunger against the tape, causing the tape to tighten around the bundle and the backup foot. As the plunger tightens the tape, a new reserve loop is formed. Any additional tape needed to form a complete reserve loop is withdrawn from a tape supply spool. As the rack moves to tighten the tape, the backup foot is detached and pulls the adjacent section of the tape against the tip of the horn of an ultrasonic transducer. After the tape is tightened, the ultrasonic transducer is actuated and the layers of tape pressed by the backup foot against the tip of the transducer are bonded (ultrasonicaliy welded) together. Thereafter, the plunger is withdrawn, the tape adjacent to the bond is cut, the backup foot is latched and the movable clamshell jaw opened.

An ultrasonic tying tool is for installation of a tape about a bundle of elongate articles. The tool includes an ultrasonic horn wherein the welding tip is moveable between a first position for welding of a tape to secure the tensioned loop about the piurality of articles and a second position wherein the welding tip is translated a distance from the first position to effect cutting of the tensioned loop from the stock of tape and to tack weld the loose cut end to the underlying tape of the loop to eliminate any protruding sharp edges. The tool additionally includes a belt drive mechanism for advancing the tape to the jaw assembly and for tensioning the tape following looping of the tape about the outside which has been stated in document of patent application US6136118

The document US3943608 states a bundling strap specially constructed to be ultrasonicaliy welded to form a locked loop about a plurality of articles to be bundled and a method for carrying out the welding. A central strap body is formed with at least one marginal strip joined to the centra! body portion along a marginal edge thereof, the marginal strip carrying an energy directing means to concentrate applied ultrasonic energy and produce a bond between such energy directing means and the overlying marginal strip. A method whereby the anvil remains outside of the strap loop permits the loop to be formed and the anvil to be easily later removed without affecting bundle tension.

S The invention stated in 1608/MUM/2014 discloses a manufacturing process of plastic ball valve by ultrasonic welding. The present invention provides plastic ball valve comprising a body, a ball, a ball pin, a handle, a rubber ring, a ball cap and pair of a bail seat specifically assembled in main body assembly and a body cap assembly sealed by ultrasonic welding. This ball valve provides excelling in economy due to the efforts devoted to the reduction of cost, enjoying light weight and high reliability, manifesting high and uniform accuracy, and enabling manufacture of compact finished ball valve. The present invention provides concealed plastic welding of essential component in seamless means and also without having additional packing material. The present invention describes process of manufacturing plastic ball valve by molding, assembling and sealing.

The other document 3051/DELNP/2013 provides a sealing jaw for sealing a packaging material using ultrasound is provided. Said sealing jaw comprises energy directing means which, for sealing purposes, can be brought in contact with an opposite surface via the packaging material and which have a substantially grid shaped or rhomboida! sealing profile.

None of these above patents, however alone or in combination, disclose the present invention. The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention. Summary of the Invention

Detailed Description of the invention with Accompanying, Drawings

For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated. The drawings are in one sheet.

The principal object of the invention is to provide an ultrasonic sealing device having a sonotrode which applies the ultrasonic vibration and an anvil as a passive counterpart.

Another principal object of the invention is to provide the ultrasonic sealing device wherein the high frequently oscillating electrical field is converted into a mechanical oscillation. The other embodiment of the invention is to provide the ultrasonic sealing device which has the beneficial effects of saving of manpower, having safety and reliability. It is among the objects of the present invention to provide an ultrasonic sealing device having a very high frequency which will rapidly and reliably seal together thin sheets of plastic materia! at a relatively high rate or production with a minimum of labor.

The other embodiment of the invention is to provide the method of sealing by using the ultrasonic sealing device wherein the high-frequency mechanical vibrations transmitted through thermoplastic parts to generate a frictional heat build-up at an interface.

The other embodiment of the invention is to provide the method of sealing by using the ultrasonic sealing device wherein the sealing time (down to 20 ms) is very sort compared to the commonly used heat contact sealing (around 500 ms).

The novel features that are considered characteristic of the present invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of certain specific embodiments, when read in connection with the accompanying drawings, in which:

Fig 1 Shows the ultrasonic sealing device according to the invention. Welding is the joining of materials under the action of heat and pressure. The heat is generated as follows:

A generator supplies high-frequency (e.g. 35 KHz) electrical energy that is converted by means of piezo-elernents in a sonic converter (converter) into mechanical longitudinal vibrations.

These high-frequency vibrations are transmitted, if necessary via a booster, to a sonotrode and, due to internal friction; heat up the plastics material to be welded.

The sonotrode is, in this connection, brought into contact with the parts to be welded.

The thermoplastic plastics material is made to flow on applying the sonotrode. On cooling under pressure a joint is produced that can transmit forces.

Depending on the plastics material, a distinction is made for example between "far- field welding¹', (suitable only for hard, brittle plastics materials with a low mechanical loss factor), in which the high-frequency vibration is conducted with low losses through the moulded part to the welding point, and "near-field welding" or "contact welding" in which the distance between the application point of the sound and the welding site is small, since the vibration is rapidly attenuated in the soft plastics material. Within last few decades the Ultrasound technology has developed into one of the most important sealing method by using of thermoplastic synthetic materials at high energy level by Ultrasound. The application field is mainly Automobile sector, Electrical & Packaging industry. The advantages of ultrasonically seaiable Valve in the field of Industrial Packaging are, very high effectiveness against failure of sealing, very less sealing time, leakage proof, recallable sealing results & very thin sealing width.

The unheated tools are very much effective for heat sensitive products like frozen food or chocolate, powdery product. Ultrasonically sealed seams are very small in consequence of the shaped tools, which helps saving packaging material, energy and costs. Even seams, which are contaminated with product, are less problematic, because the vibrating tools in connection with the small and contoured tool are pushing out the contamination of the seam during the sealing process.

The ultrasonic sealing tools (Fig1) are consisting of a sonotrode (Fig 1 b), which applies the ultrasonic vibration and an anvil [fig 1 (c)] acts as a passive counterpart. The sonotrode is oscillating in a longitudinal resonant frequency mode within the ultrasonic frequency range. Typical frequencies for ultrasonic sealing applications are in piezoelectric actor. It converts a high frequently oscillating electrical field [Fig 1 (e)] into a mechanical oscillation. The sonotrode also amplifies the oscillation, which leads to an amplitude at the sonotrode surface of 15 up to 50 prn. The anvil, which is the counterpart of the sonotrode, is reverberant and has a small contour at the laminated film [Fig 1(d)] located surface, the Anvil [Figure 1 (c)]. The energy director is needed for a defined dissipation of energy in the film pair.

To join two laminated films surface both tools were pressed together with a specific sealing force and the sonotrode starts to oscillate. Caused by the viscoe!astic losses and the surface friction between the laminated polymers films the temperature of the films rises up to the melting point and enables fusion processes. After a specific sealing time the ultrasonic impulse stops, the solidification of the material begins and the films are bonded. The laminated film/ plastic/ PP Nonwoven paper which is produced by the method of sealing by using the ultrasonic sealing device are very much effective and strong bonding happening between the materials.

The ultrasonic seal ability of different packaging materials is highly varying, even for films, which have almost identical behaviour at conductive heat sealing.

Without further elaboration, the foregoing will so fully illustrate my invention that others may, by applying current of future knowledge; readily adapt the same for use under various conditions of service. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention. Advantages over the Prior Art

The ultrasonic sealing device proposed by the present invention has the following advantages over the prior art: a) It is cost effective as compared to others machine available in the market. b) This is low operating cost.

c) It has the characteristics of simple structure, convenient use, and high efficiency.

d) It is economical in maintenances.

e) Reduces the number of labors.

f) Easily available raw material.

g) Sealing Strength is much better as compared to existing Product.

In the preceding specification, the invention has been described with reference to specific exemplary embodiments thereof. It will be evident that various modifications and changes may be made thereunto without departing from the broader spirit and scope of the invention as set forth in the claims that follow. The specification and drawings are accordingly to be regarded in an illustrative rather than restrictive sense. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. The actual scope of the invention is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.

Claims

We claim:

1) An ultrasonic sealing device which comprises a) sonotrode which applies the ultrasonic vibration and b) anvil that acts as a passive counterpart.

2) The ultrasonic sealing device as claimed in claim 1 wherein sonotrode is oscillating in a longitudinal resonant frequency mode within the ultrasonic frequency range.

3) The ultrasonic sealing device as claimed in claim 1 wherein the sonotrode amplifies the oscillation, which leads to an amplitude at the sonotrode surface of 15 up to 50 Mm.

4) The ultrasonic sealing device as claimed in claim 1 wherein the anvil which is the counterpart of the sonotrode is reverberant and has a small contour at the laminated film located surface.

5) A method of sealing the plastic by using the ultrasonic sealing device which comprises;

a) Two laminated films surface are joined by the both tools were pressed together with a specific sealing force and the sonotrode starts to oscillate. b) Due to the viscoelastic losses and the surface friction between the laminated polymer films the temperature of the films rises up to the melting point and enables fusion processes and;

c) After a specific sealing time the ultrasonic impulse stops, the solidification of the material begins and the films are bonded. 6) The method of sealing the plastic by using the ultrasonic sealing device as claimed in claim 5 wherein the high frequently oscillating electrical field is converted into a mechanical oscillation.

7) The method of sealing the plastic by using the ultrasonic sealing device as claimed in claim 5 wherein the oscillation amplified by sonotrode leads to amplitude at the sonotrode surface of 15 up to 50 μιτι.

8) The method of sealing the plastic by using the ultrasonic sealing device as claimed in claim 5 wherein the ultrasonic seal ability of different packaging materials is highly varying, even for films, which have almost identical behavior at conductive heat sealing.

9) The laminated film/ plastic/ PP Nonwoven paper produced by the method of sealing by using the ultrasonic sealing device as claimed in claim 5.