EP1702874B1 - Verfahren und Vorrichtung zum Transportieren einer Bahn nichtgewebten Materials mit elektrostatischer Aufladung in mindestens einer Zone mit einer Dimension die kleiner als die Breite der Bahn ist - Google Patents

Verfahren und Vorrichtung zum Transportieren einer Bahn nichtgewebten Materials mit elektrostatischer Aufladung in mindestens einer Zone mit einer Dimension die kleiner als die Breite der Bahn ist Download PDF

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Publication number
EP1702874B1
EP1702874B1 EP06370005A EP06370005A EP1702874B1 EP 1702874 B1 EP1702874 B1 EP 1702874B1 EP 06370005 A EP06370005 A EP 06370005A EP 06370005 A EP06370005 A EP 06370005A EP 1702874 B1 EP1702874 B1 EP 1702874B1
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EP
European Patent Office
Prior art keywords
transport
woven web
ionization
transport surface
nonwoven web
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Application number
EP06370005A
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German (de)
French (fr)
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EP1702874B8 (en
EP1702874A3 (en
EP1702874A2 (en
Inventor
Xavier Catry
Marc Barbant
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Asselin Thibeau SAS
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Asselin Thibeau SAS
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Publication of EP1702874A3 publication Critical patent/EP1702874A3/en
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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H39/00—Associating, collating, or gathering articles or webs
    • B65H39/16—Associating two or more webs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H20/00—Advancing webs
    • B65H20/02—Advancing webs by friction roller
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00—Handling processes for sheets or webs
    • B65H2301/50—Auxiliary process performed during handling process
    • B65H2301/51—Modifying a characteristic of handled material
    • B65H2301/513—Modifying electric properties
    • B65H2301/5132—Bringing electrostatic charge
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2301/00—Handling processes for sheets or webs
    • B65H2301/50—Auxiliary process performed during handling process
    • B65H2301/53—Auxiliary process performed during handling process for acting on performance of handling machine
    • B65H2301/532—Modifying characteristics of surface of parts in contact with handled material
    • B65H2301/5322—Generating electrostatic charge at said surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
    • B65H2406/00—Means using fluid
    • B65H2406/30—Suction means
    • B65H2406/31—Suction box; Suction chambers

Definitions

  • the present invention relates to an improvement, in the textile field, in the transport of a nonwoven web by means of a transport surface, and where appropriate in certain applications to the working of the longitudinal edges of the non-woven web. woven transported.
  • the present invention finds application to any type of nonwoven (nonwoven carded, nonwoven said spun based continuous filaments, nonwoven said "metlblown” obtained by molten route, nonwoven said airlaid Obtained a Vogellic way) and is preferably used before consolidation of the nonwoven web.
  • a device and method that refers to the transport of a tape and is considered to be the closest state of technology are disclosed in the document US 2004 0020962 .
  • nonwoven web generally designates any web of fibers and / or filaments or superposition of webs of fibers and / or filaments, regardless of the method of manufacture. the sail or sails, and the type of fibers or filaments.
  • the nonwoven web may consist of one or more webs of fibers or filaments selected from the list: carded nonwoven web, nonwoven web "ugly air”, nonwoven web of "meltblown” type "Spun non-woven fleece”.
  • all the sails may be of the same type, or the nonwoven may be composite, that is to say composed of several sails of different types such as for example a composite nonwoven of type CMC (carded sail / sail “meltblown” / sail carded) or type SMS (sail “spun” / sail “meltblown” / sail “spun”)
  • nonwoven generally undergoes at a later stage of its constitution one or more consolidation steps such as in particular mechanical bonding, for example by needling, hydraulic bonding. by jets of water, thermoling by calendering, or chemical bonding for example by means of an adhesive.
  • non-woven designates indifferently the veil or the superposition of veils of fibers and / or filaments before consolidation or after consolidation.
  • the transport surface during its displacement, carries with it a boundary layer of air. As long as the nonwoven web is inside this boundary layer of air, there is generally no problem. On the other hand, as soon as the nonwoven exits all or part of this limit air layer, problems of raising and turning of the nonwoven web are observed which are extremely detrimental to the quality of the non-woven web. -woven. In practice, these problems arise in all transport regions where the nonwoven web is likely to be influenced externally (for example airflow), in the regions of change of direction of transport, and in transition regions of the nonwoven web for example between two successive transport surfaces. These problems also become predominant when increasing the transport speed of the nonwoven web.
  • airflow for example airflow
  • air permeable transport surfaces are used in combination with suction means to press the nonwoven web across its entire width against the transport surface.
  • the Applicant has shown that the suction flows generated by these suction means create parasitic air circulations which are the source of problems of turning the selvedges of the nonwoven web during transport.
  • edge means a longitudinal portion of small width (relative to the width of the nonwoven web) which extends from a longitudinal edge of the nonwoven web. But the more the suction is increased to press the nonwoven web against the transport surface, the greater the risk of turning the edges of the nonwoven web by these parasitic air flows.
  • this solution for holding the conveyed nonwoven web by suction can not be used in all applications where the transport belts used are impervious to air, and for example, for transport a web of nonwoven in the coated lane to undergo the usual operations of superposition on itself (topping) of the nonwoven web in a spreader-lapper.
  • a cutting solution used to date consists in implementing at the edge of the sheet a holding plate of the non-woven strip which is applied to the strip, in combination with a suction box which is positioned at the right the edge that you want to remove, and that allows to suck all the fibers of this edge.
  • the retaining plates are very difficult to adjust: when they are not sufficiently in contact with the nonwoven web, said nonwoven web is deformed under the effect of the suction; when they are applied too strongly on the tape nonwoven, said nonwoven web is blocked and tears.
  • the present invention has the general and main objective of proposing a new technical solution for transporting a non-woven web on a transport surface (conveyor belt, rolls, etc.) which can be implemented with transport surfaces permeable or not to the air, and which reduces the risk of deformation or alteration of the structure of the web of nonwoven transported.
  • a transport surface conveyor belt, rolls, etc.
  • This objective is generally achieved by maintaining the nonwoven web with respect to the transport surface, by means of electrostatic forces, and in at least one electrostatic holding zone which has a transverse dimension reduced by relative to the width of the nonwoven web.
  • the invention thus has as its first object a method of transporting at least one nonwoven web, by means of a movable transport surface.
  • the nonwoven web and / or the transport surface are electrostatically charged so as to electrostatically adhere the nonwoven web to the transport surface in at least a first zone. in which the dimension measured in the direction perpendicular to the direction of transport is less than the width of the nonwoven web.
  • the nonwoven web and / or the transport surface is electrostatically charged so as to electrostatically adhere the nonwoven web to the transport surface in at least a second holding zone, the dimension measured in the transverse direction perpendicular to the conveying direction is smaller than the width of the nonwoven web, and which is positioned at the right of the first holding zone in the transverse direction perpendicular to the transport direction and is spaced apart from the first maintaining zone by a distance (e) measured in said transverse direction.
  • the method is used to electrostatically maintain against the transport surface and over a portion of the path, at least one selvedge and preferably the two selvedges of a nonwoven web.
  • each holding zone extends laterally in the transverse direction to the longitudinal edge of the nonwoven web.
  • each holding zone is created near a longitudinal edge of the nonwoven web but does not extend laterally in the transverse direction to that longitudinal edge.
  • the process of the invention is carried out on at least one unconsolidated nonwoven web.
  • the second object of the invention is a system for transporting at least one nonwoven web.
  • this system comprises at least one surface for transporting the nonwoven web, and at least one ionization module for locally generating a longitudinal ionizing field of small width and having a main axis of ionization oriented substantially in the transport direction of the nonwoven web and / or for locally generating an ionizing field which does not extend to the longitudinal edges of the nonwoven web.
  • a first upper belt conveyor 1 comprising a conveyor belt 1a (conveying surface) driven by rollers 1b, is used to transport a first nonwoven web W1 in the transport direction MD1 to a transfer roller 3 rotatably mounted at the end of the first conveyor.
  • This rotary transfer roller 3 allows, in a manner known per se, to transfer the first nonwoven web W1 to a second transport surface formed by the web 2a of a second lower belt conveyor 2, which is arranged below the web first conveyor 1 and the transfer roller 3.
  • the transfer roller 3 comprises a fixed suction sector 3a delimited by the fixed plates 3b, and allowing in operation to press on its periphery the nonwoven web W1 transfer course.
  • the transport surface 2a of the second lower conveyor 2 is used to transport a second nonwoven web W2 in the transport direction MD2.
  • the first nonwoven web W1 is deposited by the transfer roll 3 on the second nonwoven web W2.
  • the transport surface 2a allows, downstream of the transfer roller 3, to transport the two superposed nonwoven webs W1 and W2 in the form of a nonwoven web W3, in the direction of transport MD2, then in the transport direction MD3 after the detour roll 2b.
  • the transport and reunification system of nonwoven webs W1 and W2 described above is equipped with ionization means 4 arranged on either side of the transfer roller 3 and for electrostatically loading the selvedges of the non-woven web.
  • W2 fabric immediately upstream of the transfer roller 3 and the edges of the nonwoven web W3 immediately downstream of the transfer roller 3.
  • the ionization means comprise four ionization modules each constituted, in the particular example illustrated, an ionizing bar 4a and an ionizing brush 4b fixed in position above and in the vicinity of the nonwoven web W2 or W3.
  • the ionizing bar 4a and the ionizing brush 4b make it possible in operation, and in a manner known per se, to each generate a strong electric field saturated with ions, called the ionizing field.
  • the ionizing bar 4a and the ionizing brush 4b comprise for example a plurality of electrodes or high-voltage tips, which are powered by a high-voltage DC generator (not shown).
  • the main difference between the ionizing bar 4a and the ionizing brush 4b is the size of the ionizing field generated: elongated ionizing field in the case of the ionizing bar 4a; ionizing field of very small dimension in the case of the ionizing brush 4b.
  • an ionizing brush 4b (in addition to an ionizing bar 4a) is used so as to generate an ionizing field closest to the pinch line between the rotary transfer member 3 and the transport surface 2a.
  • the global ionizing field ZI generated by each ionization module 4 is a longitudinal field having a main ionization axis 4c.
  • each ionizing field (ZI) generated by an ionization module 4 extends laterally (direction CD) at least to the longitudinal edge B closest to the nonwoven web W2 or W3, and preferably covers said longitudinal edge as shown in the figure 3 .
  • each ionization module 4 is preferably inclined at a slight angle A with respect to the direction of transport of the nonwoven web so as to ensure the ionizing field generated covers the corresponding longitudinal edge B of the nonwoven web.
  • the angle A is less than 45 ° and depends, for a given length of a module ionization 4, the width of the ionization field (transverse direction CD) that it is desired to generate at the level of the transport surface.
  • the ionization means 4 make it possible to generate negative ions near the surface of the non-woven strip (W2 or W3) and locally in a longitudinal zone of small width. relative to the width L of the nonwoven web.
  • the transport surface 2 is made of an electrically conductive material, and acts as a mass.
  • the nonwoven webs W1, W2 (and indeed W3) consist of fibers forming a dielectric material. These are, for example, synthetic fibers based on polypropylene or polyethylene, and / or natural fibers of the cotton type, and / or artificial fibers of the viscose type.
  • the negative ions generated by the ionization means 4 thus making it possible to electrostatically charge the strips of nonwoven W2 and W3 upstream and downstream of the transfer roller 3, in localized longitudinal zones of small width (I) with respect to the width L of the nonwoven web (the dimensions I and L are measured in the transverse direction CD perpendicular to the direction of transport of the nonwoven web).
  • These longitudinal retention zones ZM of small width I are shown schematically by hatching on the figure 2 .
  • the width I of the zone is of the order of a few centimeters or tens of centimeters, and generally represents less than 1/10 of the width L of the nonwoven web.
  • these narrow width ZM holding zones (I) extend laterally (direction CD) at least to the longitudinal edges B of the nonwoven web (see FIG. figure 3 ).
  • the edges of the nonwoven web W2 electrostatically adhere to the transport surface 2 from a point ( figure 2 X1) upstream of the transfer member 3 to the region of reunification of the nonwoven webs W1 and W2 ( figure 2 / abscissa X2).
  • the selvedges of the non-woven web W3 electrostatically adhere to the transport surface 2a to a holding limit which is located in the transport direction beyond the generated ionizing fields ( figure 2 / abscissa X3). Indeed, once loaded, the nonwoven web W3 discharges more or less quickly once it leaves the ionizing field. This results in a more or less rapid loss of adhesion downstream of the generated ionizing field.
  • the position of the downstream adhesion limit of the nonwoven web W3 ( figure 2 / abscissa X3) depends in practice on several parameters including: the power of ionizing fields; the distance between the ionization means and the nonwoven web; the constituent material of the fibers or filaments of the nonwoven; the speed of transport.
  • the nonwoven web W3 adheres sufficiently to the transport surface 2a at least up to the detour roller 2b, in order to avoid raising or reversing the selvedges of the nonwoven web during the changeover.
  • transport direction MD2 to MD3.
  • the invention it is possible to avoid in a simple and economical manner the problems of turning the non-woven webs in the critical transport regions where they are likely to undergo external air and / or mechanical disturbances (in particular transfer region of a strip from one transport surface to another with, where appropriate, reunification with another nonwoven web, transport direction change region of the nonwoven web).
  • the transport surfaces can indifferently be impermeable or permeable to the air.
  • the invention is not limited to a system allowing a reunification of sail.
  • the invention may be used only at a simple transfer of a nonwoven web from one transport surface to another, and for example, in a configuration of the type of the figure 1 during the transfer of the nonwoven web W1 between the transport surfaces 1a and 2a, without using a web of nonwoven W2. In this case, it is not necessary to implement ionization modules 4 upstream of the transfer member 3.
  • the invention can be used only during a simple transport of a band of non-woven on a transport surface (without transfer and reunification with another non-woven web), for example by removing in the configuration of the figure 1 the upper conveyor 1 and the transfer member 3, and keeping only the transport surface 2a, the nonwoven web W2 and all or part of the ionization modules 4.
  • the solution which has just been described finds mainly (but not exclusively) its application to the transport of an unbound nonwoven web and / or a nonwoven web of low weight, this type of non-woven web. -woven more easily be altered by flipping their edges. Also, this solution is more particularly advantageous for high transport speeds (typically greater than 150 m / min), for which the selvedge reversal phenomena are amplified.
  • the width L of the two strips of nonwoven W1 and W2 is substantially identical. This is not limiting of the invention, the widths of the two strips of nonwoven W1 and W2 may be different.
  • each ionizing bar makes it possible to generate a longitudinal ionization field ZI of main ionization axis 4c, near and above the nonwoven strip W, so that the fibers of the nonwoven strip adhere at the transport surface 5 only in a ZM longitudinal retention zone of small width I, with respect to the width L of the nonwoven web.
  • the two ionizing bars 4a are oriented so that their main ionization axis 4c is substantially parallel to the transport direction (MD) and are positioned above the nonwoven strip and set back from the longitudinal edges B1 (before cutting), so that the two electrostatic holding zones ZM are spaced in the transverse direction CD by a distance (e) less than the width L of the non-woven strip and especially do not extend to longitudinal edges B1 of the strip (before cutting).
  • the vacuum cutting nozzle 6 has a suction opening 6a which is positioned above the edge LI of the strip to be removed and is directed towards said selvedge, and suction means (fan) for creating through said opening 6a a flow of perpendicular to the transport surface 5a ( figure 7 / arrows F).
  • the suction aperture extends in the transverse direction CD from substantially the outer longitudinal boundary 4d of the ionization field ZI to at least the longitudinal edge B1 (before cutting) of the nonwoven web W.
  • the vacuum cutting nozzle 6 is equipped with a vertical plate 6c ( figure 3 ) to better confine the suction flow F outside the ionizing field (ZI).
  • the ionizing bars 4a and the suction cutting nozzles 6 are active, and the transport surface 5a scrolls the nonwoven web in the transport direction MD, below the ionizing bars 4a and nozzles 6.
  • the constituent fibers of the outer portion of the nonwoven web W corresponding to an edge LI do not adhere (or very little) to the transport surface 5a. These fibers are thus very easily removed by suction and discharged by each nozzle 6.
  • the fibers of the nonwoven web, which adjoin the suction nozzle 6 but which are located in the ionizing field ZI adhere strongly to the transport surface 5a, which advantageously allows to obtain a perfect retention of the nonwoven web against the transport surface 5a during the cutting operation by suction edges LI.
  • the ionizing bars 4a could be replaced by any equivalent ionization means, and for example by a plurality of ionizing devices, of the type of ionizing brushes described in the first application above, substantially aligned in the MD transport direction.
  • the ionizing bars 4a could also be slightly inclined at an angle A with respect to the transport direction MD.
  • the ionization module 4 is constituted by two ionizing bars 4a aligned in the transverse direction CD.
  • the main ionization axis 4c of the ionization module 4 extends substantially perpendicular to the direction of transport (MD), the essential in this application (as well as in the application below of the figure 10 ) being that the electrostatic holding zone (s) ZM do not extend to the longitudinal edges B1 (before cutting) of the nonwoven web W.
  • the application of the figure 10 relates to a vacuum cutting system with LI edge profiling of an unbound nonwoven web W.
  • the system differs from the above-mentioned cutting systems Figures 7 to 9 only by the lateral position of each nozzle 6 in the transverse direction CD.
  • a portion of the suction opening 6a is disposed in the ionizing field ZI (i.e. at the fibers adhering to the transport surface 5) and the other part of the opening of the suction 6a is disposed outside the ionizing field ZI.
  • This technical solution for profiling the edges of a non-woven non-woven fabric is particularly useful in the nap, that is to say in all applications where the non-woven non-woven web W feeds a crosslapper in order to forming a nonwoven web by turning and folding the nonwoven web around itself.
  • the transport surfaces are flat. This is not limiting of the invention. In other applications of the invention, the transport surfaces may be curved, and in particular cylindrical.
  • the adhesion of the nonwoven web to the transport surface is obtained by electrostatically charging the nonwoven web.
  • the same adhesion effect can be obtained by electrostatically charging only the transport surface.
  • the same adhesion effect can be obtained by electrostatically charging both the transport surface and the nonwoven web, but with opposite polarities.

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  • Treatment Of Fiber Materials (AREA)
  • Nonwoven Fabrics (AREA)

Description

Domaine techniqueTechnical area

La présente invention concerne un perfectionnement, apporté dans le domaine textile, au transport d'une bande de non-tissé au moyen d'une surface de transport, et le cas échéant dans certaines applications au travail des bords longitudinaux de la bande de non-tissé transportée. La présente invention trouve son application à tout type de non-tissé ( non-tissé cardé, non-tissé dit «spun» à base de filaments continus, non-tissé dit « metlblown» obtenu par voie fondue , non-tissé dit « airlaid » obtenu par voie aéraulique) et est utilisée de préférence avant consolidation de la bande de non-tissé.The present invention relates to an improvement, in the textile field, in the transport of a nonwoven web by means of a transport surface, and where appropriate in certain applications to the working of the longitudinal edges of the non-woven web. woven transported. The present invention finds application to any type of nonwoven (nonwoven carded, nonwoven said spun based continuous filaments, nonwoven said "metlblown" obtained by molten route, nonwoven said airlaid Obtained aeraulic way) and is preferably used before consolidation of the nonwoven web.

Un dispositif et un procédé qui se réfèrent au transport d'une bande et sont considérés comme l'état de technique le plus proche sont divulgués dans le document US 2004 0020962 .A device and method that refers to the transport of a tape and is considered to be the closest state of technology are disclosed in the document US 2004 0020962 .

Art antérieurPrior art Non-tisséNonwoven

Dans le présent texte, on désigne d'une manière générale par les termes « bande de non-tissé », tout voile de fibres et/ou de filaments ou superposition de voiles de fibres et/ou de filaments, indépendamment de la méthode de fabrication du ou des voiles, et du type de fibres ou filaments. En particulier, la bande de non-tissé peut être constituée d'un ou plusieurs voiles de fibres ou filaments choisis parmi la liste : voile non-tissé cardé, voile non-tissé « air laid », voile non-tissé de type « meltblown », voile non-tissé de type « spun ». En cas de pluralité de voiles superposés, tous les voiles peuvent être du même type, ou le non-tissé peut être composite, c'est-à-dire constitué de plusieurs voiles de types différents tel que par exemple un non-tissé composite de type CMC (voile cardé/voile « meltblown »/voile cardé) ou encore de type SMS (voile « spun »/voile « meltblown »/ voile « spun »)In the present text, the term "nonwoven web" generally designates any web of fibers and / or filaments or superposition of webs of fibers and / or filaments, regardless of the method of manufacture. the sail or sails, and the type of fibers or filaments. In particular, the nonwoven web may consist of one or more webs of fibers or filaments selected from the list: carded nonwoven web, nonwoven web "ugly air", nonwoven web of "meltblown" type "Spun non-woven fleece". In the case of a plurality of superimposed sails, all the sails may be of the same type, or the nonwoven may be composite, that is to say composed of several sails of different types such as for example a composite nonwoven of type CMC (carded sail / sail "meltblown" / sail carded) or type SMS (sail "spun" / sail "meltblown" / sail "spun")

Il est rappelé qu'un non-tissé subit généralement à un stade ultérieur de sa constitution une ou plusieurs étapes de consolidation tel que notamment liage mécanique par exemple par aiguilletage, liage hydraulique par jets d'eau, thermoliage par calandrage, ou liage chimique par exemple au moyen d'un adhésif. Dans le présent texte, le terme « non-tissé » désigne indifféremment le voile ou la superposition de voiles de fibres et/ou filaments avant consolidation ou après consolidation.It is recalled that a nonwoven generally undergoes at a later stage of its constitution one or more consolidation steps such as in particular mechanical bonding, for example by needling, hydraulic bonding. by jets of water, thermoling by calendering, or chemical bonding for example by means of an adhesive. In the present text, the term "non-woven" designates indifferently the veil or the superposition of veils of fibers and / or filaments before consolidation or after consolidation.

Transport du non-tisséTransport of the nonwoven

Pour transporter un non-tissé (en cours de fabrication ou après fabrication pour lui faire subir des étapes de traitement ultérieur), il est connu d'utiliser une ou plusieurs surfaces de transport successives, du type bandes de transport ou cylindres, sur laquelle ou lesquelles est posée la bande de non-tissé.In order to transport a nonwoven fabric (during manufacture or after manufacture for subjecting it to further processing steps), it is known to use one or more successive transport surfaces, of the transport belt or cylinder type, on which which is laid the nonwoven web.

La surface de transport, au cours de son déplacement, entraîne avec elle une couche d'air limite. Tant que la bande de non-tissé est à l'intérieur de cette couche d'air limite, on ne rencontre généralement pas de problème. En revanche, dès que le non-tissé sort en tout ou partie de cette couche d'air limite, on observe des problèmes de soulèvement et de retournement de la bande de non-tissé qui sont extrêmement préjudiciables à la qualité de la bande de non-tissé. En pratique, ces problèmes se posent dans toutes les régions de transport où la bande de non-tissé est susceptible de subir une influence extérieur (par exemple un flux d'air), dans les régions de changement de direction de transport, et dans les régions de transition de la bande non-tissé par exemple entre deux surfaces de transport successives. Ces problèmes deviennent également prépondérants lorsqu'on augmente la vitesse de transport de la bande de non-tissé.The transport surface, during its displacement, carries with it a boundary layer of air. As long as the nonwoven web is inside this boundary layer of air, there is generally no problem. On the other hand, as soon as the nonwoven exits all or part of this limit air layer, problems of raising and turning of the nonwoven web are observed which are extremely detrimental to the quality of the non-woven web. -woven. In practice, these problems arise in all transport regions where the nonwoven web is likely to be influenced externally (for example airflow), in the regions of change of direction of transport, and in transition regions of the nonwoven web for example between two successive transport surfaces. These problems also become predominant when increasing the transport speed of the nonwoven web.

Pour pallier ces problèmes, on utilise à ce jour des surfaces de transport perméables à l'air en combinaison avec des moyens d'aspiration permettant de plaquer la bande de non-tissé sur toute sa largeur contre la surface de transport.To alleviate these problems, air permeable transport surfaces are used in combination with suction means to press the nonwoven web across its entire width against the transport surface.

Ces solutions sont onéreuses et contraignantes, notamment en termes de réglage de l'aspiration.These solutions are expensive and restrictive, especially in terms of suction adjustment.

D'autre part, et surtout, la demanderesse a mis en évidence que les flux d'aspiration engendrés par ces moyens d'aspiration créent des circulations d'air parasites qui sont la source de problèmes de retournement des lisières de la bande de non-tissé en cours de transport. Dans le présent texte, on désigne par le terme « lisière», une portion longitudinale de faible largeur (par rapport à la largeur de la bande de non-tissé) qui s'étend depuis un bord longitudinal de la bande de non-tissé. Or plus on augmente l'aspiration pour plaquer la bande de non-tissé contre la surface de transport, plus on augmente les risques de retournement des lisères de la bande de non-tissé par ces flux d'air parasites. Ces problèmes de retournement des lisières de la bande de non-tissé en cours de transport sont amplifiés lorsqu'on augmente la vitesse de transport.On the other hand, and above all, the Applicant has shown that the suction flows generated by these suction means create parasitic air circulations which are the source of problems of turning the selvedges of the nonwoven web during transport. In the present text, the term "edge" means a longitudinal portion of small width (relative to the width of the nonwoven web) which extends from a longitudinal edge of the nonwoven web. But the more the suction is increased to press the nonwoven web against the transport surface, the greater the risk of turning the edges of the nonwoven web by these parasitic air flows. These problems of turning the selvedges of the nonwoven web during transport are amplified when increasing the transport speed.

Enfin, de manière limitative cette solution de maintien par aspiration de la bande de non-tissé transportée ne peut pas être mise en oeuvre dans toutes les applications où les bandes de transport utilisées sont imperméables à l'air, et par exemple, pour le transport d'une bande de non-tissé dans la voie nappée en vue de lui faire subir les opérations usuelles de superposition sur elle-même (nappage) de la bande de non-tissé dans un étaleur-nappeur.Finally, in a limiting manner, this solution for holding the conveyed nonwoven web by suction can not be used in all applications where the transport belts used are impervious to air, and for example, for transport a web of nonwoven in the coated lane to undergo the usual operations of superposition on itself (topping) of the nonwoven web in a spreader-lapper.

Travail des lisières d'une bande de non-tisséWorking edges of a non-woven strip

Dans certaines applications, on cherche également à travailler les lisières de la bande de non-tissé transportée.In some applications, it is also sought to work the edges of the nonwoven web transported.

Par exemple, dans le but de calibrer la largeur de la bande de non-tissé, on réalise des découpes en cours de transport des lisières de la bande de non-tissé. Une solution de découpe utilisée à ce jour consiste à mettre en oeuvre au niveau de la lisère une tôle de maintien de la bande de non-tissé qui est appliquée sur la bande, en combinaison avec une boîte d'aspiration qui est positionnée au droit de la lisière que l'on souhaite retirer, et qui permet d'aspirer toutes les fibres de cette lisière.For example, in order to calibrate the width of the nonwoven web, cuts are made during transport of the selvedges of the nonwoven web. A cutting solution used to date consists in implementing at the edge of the sheet a holding plate of the non-woven strip which is applied to the strip, in combination with a suction box which is positioned at the right the edge that you want to remove, and that allows to suck all the fibers of this edge.

Dans cette solution de calibrage par aspiration, les tôles de maintien sont très difficiles à régler : lorsqu'elles ne sont pas suffisamment en contact avec la bande de non-tissé, ladite bande de non-tissé se déforme sous l'effet de l'aspiration ; lorsqu'elles sont appliquées trop fortement sur la bande de non-tissé, ladite bande de non-tissé se bloque et se déchire.In this suction calibration solution, the retaining plates are very difficult to adjust: when they are not sufficiently in contact with the nonwoven web, said nonwoven web is deformed under the effect of the suction; when they are applied too strongly on the tape nonwoven, said nonwoven web is blocked and tears.

Objectif de l'inventionObjective of the invention

La présente invention a pour objectif général et principal de proposer une nouvelle solution technique pour le transport d'une bande de non-tissé sur une surface de transport (bande de transport, cylindres,...) qui peut être mise en oeuvre avec des surfaces de transport perméables ou non à l'air, et qui permet de réduire les risques de déformation ou d'altération de la structure de la bande de non-tissé transportée.The present invention has the general and main objective of proposing a new technical solution for transporting a non-woven web on a transport surface (conveyor belt, rolls, etc.) which can be implemented with transport surfaces permeable or not to the air, and which reduces the risk of deformation or alteration of the structure of the web of nonwoven transported.

Résumé de l'inventionSummary of the invention

Cet objectif est atteint d'une manière générale en réalisant un maintien de la bande de non-tissé par rapport à la surface de transport, au moyen de forces électrostatiques, et dans au moins une zone de maintien électrostatique qui présente une dimension transversale réduite par rapport à la largeur de la bande de non-tissé.This objective is generally achieved by maintaining the nonwoven web with respect to the transport surface, by means of electrostatic forces, and in at least one electrostatic holding zone which has a transverse dimension reduced by relative to the width of the nonwoven web.

L'invention a ainsi pour premier objet un procédé de transport d'au moins une bande de non-tissé, au moyen d'une surface de transport mobile.The invention thus has as its first object a method of transporting at least one nonwoven web, by means of a movable transport surface.

Selon une première caractéristique du procédé de l'invention, on charge électrostatiquement la bande de non-tissé et/ou la surface de transport en sorte de faire adhérer électrostatiquement la bande de non-tissé sur la surface de transport dans au moins une première zone de maintien dont la dimension mesurée dans la direction perpendiculaire à la direction de transport est inférieure à la largeur de la bande de non-tissé.According to a first characteristic of the process of the invention, the nonwoven web and / or the transport surface are electrostatically charged so as to electrostatically adhere the nonwoven web to the transport surface in at least a first zone. in which the dimension measured in the direction perpendicular to the direction of transport is less than the width of the nonwoven web.

Dans une variante préférée de réalisation, on charge électrostatiquement la bande de non-tissé et/ou la surface de transport en sorte de faire adhérer électrostatiquement la bande de non-tissé sur la surface de transport dans au moins une deuxième zone de maintien, dont la dimension mesurée dans la direction transverse perpendiculaire à la direction de transport est inférieure à la largeur de la bande de non-tissé, et qui est positionnée au droit de la première zone de maintien dans la direction transverse perpendiculaire à la direction de transport et est espacée de la première zone de maintien d'une distance (e) mesurée dans ladite direction transverse.In a preferred embodiment, the nonwoven web and / or the transport surface is electrostatically charged so as to electrostatically adhere the nonwoven web to the transport surface in at least a second holding zone, the dimension measured in the transverse direction perpendicular to the conveying direction is smaller than the width of the nonwoven web, and which is positioned at the right of the first holding zone in the transverse direction perpendicular to the transport direction and is spaced apart from the first maintaining zone by a distance (e) measured in said transverse direction.

Dans une première application, le procédé est utilisé pour maintenir électrostatiquement contre la surface de transport et sur une partie du trajet, au moins une lisière et de préférence les deux lisières d'une bande de non-tissé. A cet effet, chaque zone de maintien s'étend latéralement dans la direction transverse jusqu'au bord longitudinal de la bande de non-tissé.In a first application, the method is used to electrostatically maintain against the transport surface and over a portion of the path, at least one selvedge and preferably the two selvedges of a nonwoven web. For this purpose, each holding zone extends laterally in the transverse direction to the longitudinal edge of the nonwoven web.

Dans le cadre de cette première application, le procédé de transport de l'invention comporte plus particulièrement les caractéristiques additionnelles et facultatives ci-après, prises isolément ou le cas échéant en combinaison :

  • on transporte une première bande de non-tissé au moyen d'une première surface de transport jusqu'à une deuxième surface de transport ; on transfère la première bande de non-tissé sur ladite deuxième surface de transport ; on transporte ladite première bande de non-tissé au moyen de la deuxième surface de transport ; chaque zone de maintien est créée immédiatement en aval de la région de transfert entre la première et de la deuxième surface de transport ;
  • on transporte au moyen de la deuxième surface de transport une deuxième bande de non-tissé qui a été déposée sur la deuxième surface de transport en amont de la zone de transfert de la première bande de non-tissé, de telle sorte que la première bande de non-tissé est transférée sur la deuxième bande de non-tissé en sorte de former avec cette deuxième bande une troisième bande de non-tissé; on crée au moins deux zones de maintien supplémentaires (ZM) en chargeant électrostatiquement la deuxième bande de non-tissé et/ou la deuxième surface de transport en amont de la région de transfert en sorte de faire adhérer électrostatiquement la deuxième bande de non-tissé sur la deuxième surface de transport en amont de la région de transfert de la première bande de non-tissé, la largeur de chaque zone de maintien amont mesurée dans la direction perpendiculaire à la direction de transport étant inférieure à la largeur de la deuxième bande de non-tissé, et les deux zones de maintien amont s'étendant respectivement jusqu'aux deux bords longitudinaux de la deuxième bande de non-tissé ;
  • le transfert de la première bande de non-tissé sur la deuxième surface de transport est réalisé au moyen d'un organe de transfert rotatif, de préférence aspirant.
In the context of this first application, the transport method of the invention more particularly comprises the additional and optional characteristics hereafter, taken alone or, if appropriate, in combination:
  • transporting a first nonwoven web by means of a first transport surface to a second transport surface; transferring the first nonwoven web to said second transport surface; transporting said first nonwoven web by means of the second transport surface; each holding zone is created immediately downstream of the transfer region between the first and second transport surfaces;
  • a second non-woven web is transported by means of the second transport surface which has been deposited on the second transport surface upstream of the transfer zone of the first non-woven web, so that the first web nonwoven is transferred onto the second nonwoven web so as to form with this second web a third nonwoven web; at least two additional holding zones (ZM) are created by electrostatically charging the second nonwoven web and / or the second transport surface upstream of the transfer region so as to electrostatically adhere the second web of nonwoven on the second transport surface upstream of the transfer region of the first nonwoven web, the width of each upstream holding zone measured in the direction perpendicular to the transport direction being less than the width of the second non-woven web; woven, and the two upstream holding zones extending respectively to the two longitudinal edges of the second nonwoven web;
  • the transfer of the first non-woven web to the second transport surface is effected by means of a rotatable transfer member, preferably suction.

Dans d'autres applications de l'invention, chaque zone de maintien est créée à proximité d'un bord longitudinal de la bande de non-tissé mais ne s'étend pas latéralement dans la direction transverse jusqu'à ce bord longitudinal.In other applications of the invention, each holding zone is created near a longitudinal edge of the nonwoven web but does not extend laterally in the transverse direction to that longitudinal edge.

Plus particulièrement dans ces autres applications, le procédé de l'invention comporte les caractéristiques additionnelles et facultatives ci-après, prises isolément ou le cas échéant en combinaison :

  • dans une zone de travail qui est localisée selon la direction de transport à une position comprise entre le début et la fin d'une zone de maintien électrostatique, on exerce une action sur la lisière de la bande de non-tissé ;
  • ladite action consiste à découper la lisière ;
  • ladite action consiste à retirer une partie des fibres de la lisière en sorte de lui conférer un profil aminci ;
  • ladite action exercée sur la lisière de la bande de non-tissé est réalisée au moyen d'une aspiration ;
More particularly in these other applications, the method of the invention comprises the following additional and optional features, taken separately or, if appropriate, in combination:
  • in a work zone which is located in the direction of transport at a position between the beginning and the end of an electrostatic holding zone, an action is exerted on the edge of the nonwoven web;
  • said action consists in cutting the selvedge;
  • said action is to remove a portion of the fibers of the selvedge so as to confer a thinned profile;
  • said action exerted on the edge of the nonwoven web is performed by means of suction;

De préférence, quelle que soit l'application, le procédé de l'invention est mis en oeuvre sur au moins une bande de non-tissé non consolidée.Preferably, whatever the application, the process of the invention is carried out on at least one unconsolidated nonwoven web.

L'invention a pour deuxième objet un système pour le transport d'au moins une bande de non-tissé.The second object of the invention is a system for transporting at least one nonwoven web.

Selon une première caractéristique générale, ce système comporte au moins une surface de pour le transport de la bande de non-tissé, et au moins un module d'ionisation permettant de générer localement un champ ionisant longitudinal de faible largeur et présentant un axe principal d'ionisation orienté essentiellement selon la direction de transport de la bande de non-tissé et/ou permettant de générer localement un champ ionisant qui ne s'étend pas jusqu'aux bords longitudinaux de la bande de non-tissé.According to a first general characteristic, this system comprises at least one surface for transporting the nonwoven web, and at least one ionization module for locally generating a longitudinal ionizing field of small width and having a main axis of ionization oriented substantially in the transport direction of the nonwoven web and / or for locally generating an ionizing field which does not extend to the longitudinal edges of the nonwoven web.

Plus particulièrement, le système de l'invention comporte les caractéristiques additionnelles et facultatives ci-après, prises isolément ou le cas échéant en combinaison :

  • un module d'ionisation comprend une barre ionisante et/ou une pluralité de dispositifs d'ionisation sensiblement alignés selon l'axe principal d'ionisation ;
  • le système permet le maintien électrostatique des lisières d'une bande de non-tissé ; dans ce cas l'axe principal d'ionisation de chaque module d'ionisation est de préférence incliné d'un angle inférieur à 45° par rapport à la direction de transport de la bande de non-tissé ;
  • le système comporte une première surface de transport et une deuxième surface de transport, la première surface de transport permettant en fonctionnement d'acheminer une bande de non-tissé jusqu'à la deuxième surface de transport; il comporte en outre deux modules d'ionisation disposés en aval de la région de transfert entre les deux surfaces de transport, et espacés l'un de l'autre selon direction transversale perpendiculaire à la direction de transport ;
  • le système permet la réunification par superposition de deux bandes de non-tissé ; dans ce cas, il comporte de préférence deux modules d'ionisation disposés en amont de la région de transfert entre les deux surfaces de transport, et espacés l'un de l'autre selon la direction transversale perpendiculaire à la direction de transport ;
  • le système comporte un organe de transfert rotatif interposé entre les deux surfaces de transport ;
  • le système comporte des moyens d'aspiration associés à un module d'ionisation et permettant une découpe par aspiration d'au moins une lisière d'une bande de non-tissé ; plus particulièrement, les moyens d'aspiration comportent une ouverture d'aspiration positionnée à la frontière et en dehors du champ d'ionisation du module d'ionisation associé ;
  • les moyens d'aspiration comportent une ouverture d'aspiration positionnée en partie dans le champ d'ionisation du module d'ionisation en sorte de permettre une découpe avec profilage de la lisière (LI) d'une bande de non-tissé.
  • l'axe principal d'ionisation de chaque module d'ionisation est sensiblement parallèle à la direction transport.
More particularly, the system of the invention comprises the following additional and optional features, taken separately or, where appropriate, in combination:
  • an ionization module comprises an ionizing bar and / or a plurality of ionization devices substantially aligned along the main axis of ionization;
  • the system allows the electrostatic retention of the edges of a nonwoven web; in this case the main ionization axis of each ionization module is preferably inclined at an angle less than 45 ° with respect to the transport direction of the nonwoven web;
  • the system includes a first conveying surface and a second conveying surface, the first conveying surface operatively conveying a nonwoven web to the second transport surface; it further comprises two ionization modules arranged downstream of the transfer region between the two transport surfaces, and spaced apart from each other in transverse direction perpendicular to the direction of transport;
  • the system allows the reunification by superposition of two strips of nonwoven; in this case, it preferably comprises two ionization modules arranged upstream of the transfer region between the two transport surfaces, and spaced apart from each other in the transverse direction perpendicular to the direction of transport;
  • the system comprises a rotary transfer member interposed between the two transport surfaces;
  • the system comprises suction means associated with an ionization module and allowing vacuum cutting of at least one edge of a nonwoven web; more particularly, the suction means comprise a suction opening positioned at the boundary and outside the ionization field of the associated ionization module;
  • the suction means comprise a suction opening positioned in part in the ionization field of the ionization module so as to allow cutting with profiling of the edge (LI) of a nonwoven web.
  • the main ionization axis of each ionization module is substantially parallel to the transport direction.

Brève description des figuresBrief description of the figures

D'autres caractéristiques et avantages de l'invention apparaîtront plus clairement à la lecture de la description détaillée ci-après de plusieurs exemples préférés de réalisation de l'invention, laquelle description est donnée à titre d'exemple non limitatif et non exhaustif de l'invention, et en référence aux dessins annexés sur lesquels :

  • la figure 1 est une représentation schématique, vu de côté, d'un système de réunification de deux bandes de non-tissé incorporant des moyens de charge électrostatique qui sont conformes à l'invention et réalisés selon une première variante de réalisation,
  • la figure 2 est une vue de dessus du système de la figure 1, le convoyeur à bande supérieur dudit système de réunification n'étant pas représenté,
  • la figure 3 est un agrandissement, en vue schématique de dessus, d'un module de charge électrostatique du système des figures 1 et 2,
  • la figure 4 est une représentation schématique, vu de côté, d'un système de réunification de deux bandes de non-tissé incorporant des moyens de charge électrostatique, qui sont conformes à l'invention et réalisés selon une deuxième variante de réalisation,
  • la figure 5 est une vue de dessus du système de la figure 4, le convoyeur à bande supérieur dudit système de réunification n'étant pas représenté,
  • la figure 6 est un agrandissement, en vue schématique de dessus, d'un module de charge électrostatique du système des figures 4 et 5,
  • la figure 7 est une vue schématique de dessus d'une première variante de réalisation d'un système de découpe des lisières d'une bande de non-tissé, qui est conforme à l'invention,
  • la figure 8 est une vue schématique en section transversale du système de découpe de la figure 7, dans un le plan VIII-VIII de la figure 7,
  • la figure 9 une vue schématique de dessus d'une deuxième variante de réalisation d'un système de découpe des lisières d'une bande de non-tissé, qui est conforme à l'invention, et
  • la figure 10 est une vue schématique en section transversale d'un système de l'invention permettant un profilage en biseau des lisières d'une bande de non-tissé.
Other features and advantages of the invention will appear more clearly on reading the following detailed description of several preferred embodiments of the invention, which description is given by way of non-limiting and non-exhaustive example of the invention. invention, and with reference to the accompanying drawings in which:
  • the figure 1 is a diagrammatic representation, seen from the side, of a reunification system of two non-woven strips incorporating electrostatic charging means which are in accordance with the invention and produced according to a first variant embodiment,
  • the figure 2 is a top view of the system of the figure 1 the upper belt conveyor of said reunification system not being shown,
  • the figure 3 is an enlargement, in schematic view from above, of an electrostatic charge module of the system of Figures 1 and 2 ,
  • the figure 4 is a schematic representation, seen from the side, of a reunification system of two non-woven strips incorporating electrostatic charging means, which are in accordance with the invention and made according to a second variant embodiment,
  • the figure 5 is a top view of the system of the figure 4 the upper belt conveyor of said reunification system not being shown,
  • the figure 6 is an enlargement, in schematic view from above, of an electrostatic charge module of the system of Figures 4 and 5 ,
  • the figure 7 is a diagrammatic view from above of a first variant embodiment of a system for cutting the selvedges of a non-woven strip, which is in accordance with the invention,
  • the figure 8 is a schematic cross-sectional view of the cutting system of the figure 7 , in a plan VIII-VIII of the figure 7 ,
  • the figure 9 a schematic view from above of a second variant embodiment of a system for cutting the selvedges of a non-woven strip, which is in accordance with the invention, and
  • the figure 10 is a schematic cross-sectional view of a system of the invention allowing bevel profiling of the edges of a nonwoven web.

Description détailléedetailed description 1ère application : Maintien d'une bande de non-tissé en cours de transport 1 application era: Maintaining a nonwoven current conveyor belt

Une première application de l'invention dédiée au maintien des lisères d'une bande de non-tissé en cours de transport va à présent être détaillée en référence à aux figures 1 à 3 (1ère variante) et aux figures 4 à 6 (2ème variante).A first application of the invention dedicated to maintaining the edges of a nonwoven web during transport will now be detailed with reference to Figures 1 to 3 ( First variant) and to Figures 4 to 6 ( 2nd variant).

En référence à la figure 1 (1ère variante) et à la figure 4 (2ème variante), dans l'application particulière visée sur ces figures, un premier convoyeur à bande 1 supérieur, comportant une bande de transport 1a (surface de transport) entraînée par des rouleaux 1b, est utilisé pour transporter une première bande de non-tissé W1 dans la direction de transport MD1 jusqu'à un rouleau de transfert 3 monté rotatif à l'extrémité du premier convoyeur. Ce rouleau de transfert rotatif 3 permet de manière connue en soi de transférer la première bande de non-tissé W1 sur une deuxième surface de transport constituée par la bande 2a d'un deuxième convoyeur à bande 2 inférieur, qui est disposé au-dessous du premier convoyeur 1 et du rouleau de transfert 3. De préférence, le rouleau de transfert 3 comporte un secteur d'aspiration fixe 3a délimité par les tôles fixes 3b, et permettant en fonctionnement de plaquer sur sa périphérie la bande de non-tissé W1 en cours de transfert.With reference to the figure 1 (1 st variation) and figure 4 ( 2nd variant), in the particular application referred to in these figures, a first upper belt conveyor 1, comprising a conveyor belt 1a (conveying surface) driven by rollers 1b, is used to transport a first nonwoven web W1 in the transport direction MD1 to a transfer roller 3 rotatably mounted at the end of the first conveyor. This rotary transfer roller 3 allows, in a manner known per se, to transfer the first nonwoven web W1 to a second transport surface formed by the web 2a of a second lower belt conveyor 2, which is arranged below the web first conveyor 1 and the transfer roller 3. Preferably, the transfer roller 3 comprises a fixed suction sector 3a delimited by the fixed plates 3b, and allowing in operation to press on its periphery the nonwoven web W1 transfer course.

La surface de transport 2a du deuxième convoyeur inférieur 2 est utilisée pour transporter une deuxième bande de non-tissé W2 dans la direction de transport MD2.The transport surface 2a of the second lower conveyor 2 is used to transport a second nonwoven web W2 in the transport direction MD2.

En fonctionnement, la première bande de non-tissé W1 est déposée par le rouleau de transfert 3 sur la deuxième bande de non-tissé W2. La surface de transport 2a permet, en aval du rouleau de transfert 3, de transporter les deux bandes de non-tissé W1 et W2 superposées sous la forme d'une bande de non-tissé W3, dans la direction de transport MD2, puis dans la direction de transport MD3 après le rouleau détour 2b.In operation, the first nonwoven web W1 is deposited by the transfer roll 3 on the second nonwoven web W2. The transport surface 2a allows, downstream of the transfer roller 3, to transport the two superposed nonwoven webs W1 and W2 in the form of a nonwoven web W3, in the direction of transport MD2, then in the transport direction MD3 after the detour roll 2b.

Première variante / Figures 1 à 3First variant / Figures 1 to 3

Le système de transport et de réunification des bandes de non-tissé W1 et W2 précédemment décrit est équipé de moyens d'ionisation 4 disposés de part et d'autre du rouleau de transfert 3 et permettant de charger électrostatiquement les lisières de la bande de non-tissé W2 immédiatement en amont du rouleau de transfert 3 et les lisières de la bande de non-tissé W3 immédiatement en aval du rouleau de transfert 3.The transport and reunification system of nonwoven webs W1 and W2 described above is equipped with ionization means 4 arranged on either side of the transfer roller 3 and for electrostatically loading the selvedges of the non-woven web. W2 fabric immediately upstream of the transfer roller 3 and the edges of the nonwoven web W3 immediately downstream of the transfer roller 3.

Plus particulièrement, les moyens d'ionisation comportent quatre modules d'ionisation constitués chacun, dans l'exemple particulier illustré, d'une barre ionisante 4a et d'un pinceau ionisant 4b fixés en position au-dessus et à proximité de la bande de non-tissé W2 ou W3.More particularly, the ionization means comprise four ionization modules each constituted, in the particular example illustrated, an ionizing bar 4a and an ionizing brush 4b fixed in position above and in the vicinity of the nonwoven web W2 or W3.

La barre ionisante 4a et le pinceau ionisant 4b permettent en fonctionnement, et de manière connue en soi, de générer chacun un champ électrique puissant, saturé en ions, dit champ ionisant. A cet effet, la barre ionisante 4a et le pinceau ionisant 4b comportent par exemple une pluralité d'électrodes ou pointes haute tension, qui sont alimentées par un générateur de haute tension continue (non représenté). La principale différence entre la barre ionisante 4a et le pinceau ionisant 4b est la taille du champ ionisant généré : champ ionisant allongé dans le cas de la barre ionisante 4a ; champ ionisant de très faible dimension dans le cas du pinceau ionisant 4b. Dans l'exemple illustré sur les figures 1 à 3, on utilise un pinceau ionisant 4b (en complément d'une barre ionisante 4a) en sorte de générer un champ ionisant au plus près de la ligne de pincement entre l'organe de transfert rotatif 3 et la surface de transport 2a.The ionizing bar 4a and the ionizing brush 4b make it possible in operation, and in a manner known per se, to each generate a strong electric field saturated with ions, called the ionizing field. For this purpose, the ionizing bar 4a and the ionizing brush 4b comprise for example a plurality of electrodes or high-voltage tips, which are powered by a high-voltage DC generator (not shown). The main difference between the ionizing bar 4a and the ionizing brush 4b is the size of the ionizing field generated: elongated ionizing field in the case of the ionizing bar 4a; ionizing field of very small dimension in the case of the ionizing brush 4b. In the example shown on the Figures 1 to 3 , an ionizing brush 4b (in addition to an ionizing bar 4a) is used so as to generate an ionizing field closest to the pinch line between the rotary transfer member 3 and the transport surface 2a.

Le champ ionisant global ZI généré par chaque module d'ionisation 4 est un champ longitudinal présentant un axe principal ionisation 4c.The global ionizing field ZI generated by each ionization module 4 is a longitudinal field having a main ionization axis 4c.

Sur la figure 3, on a schématisé par des hachures, la zone d'ionisation sensiblement couverte latéralement (dans la direction transversale CD) par le champ d'ionisation globale ZI d'un module d'ionisation 4 (barre ionisante 4a + pinceau ionisant adjacent 4b). Dans l'application visée, chaque champ ionisant (ZI) généré par un module d'ionisation 4 s'étend latéralement (direction CD) au moins jusqu'au bord longitudinal B le plus proche de la bande de non-tissé W2 ou W3, et de préférence couvre ledit bord longitudinal tel que cela est illustré sur la figure 3. Dans l'exemple des figures 2 et 3, on peut noter que l'axe principal d'ionisation 4c de chaque module d'ionisation 4 est de préférence incliné d'un faible angle A par rapport à la direction de transport de la bande de non-tissé en sorte de s'assurer que le champ ionisant généré couvre le bord longitudinal B correspondant de la bande de non-tissé. L'angle A est inférieur à 45° et dépend, pour une longueur donnée d'un module d'ionisation 4, de la largeur du champ d'ionisation (direction transversale CD) que l'on souhaite générer au niveau de la surface de transport.On the figure 3 the ionization zone substantially covered laterally (in the transverse direction CD) by the global ionization field ZI of an ionization module 4 (ionizing bar 4a + adjacent ionizing brush 4b) has been schematized by hatching. In the intended application, each ionizing field (ZI) generated by an ionization module 4 extends laterally (direction CD) at least to the longitudinal edge B closest to the nonwoven web W2 or W3, and preferably covers said longitudinal edge as shown in the figure 3 . In the example of Figures 2 and 3 it may be noted that the main ionization axis 4c of each ionization module 4 is preferably inclined at a slight angle A with respect to the direction of transport of the nonwoven web so as to ensure the ionizing field generated covers the corresponding longitudinal edge B of the nonwoven web. The angle A is less than 45 ° and depends, for a given length of a module ionization 4, the width of the ionization field (transverse direction CD) that it is desired to generate at the level of the transport surface.

Plus particulièrement, dans les exemples particuliers illustrés sur les figures, les moyens d'ionisation 4 permettent de générer des ions négatifs à proximité de la surface de la bande de non-tissé (W2 ou W3) et localement dans une zone longitudinale de faible largeur par rapport à la largeur L de la bande de non-tissé. La surface de transport 2 est réalisée dans un matériau électriquement conducteur, et fait office de masse. Les bandes de non-tissé W1, W2 (et de fait W3) sont constituées de fibres formant un matériau diélectrique. Il s'agit par exemple de fibres synthétiques à base de polypropylène ou polyéthylène, et/ou de fibres naturelles du type coton, et/ou de fibres artificielles de type viscose.More particularly, in the particular examples illustrated in the figures, the ionization means 4 make it possible to generate negative ions near the surface of the non-woven strip (W2 or W3) and locally in a longitudinal zone of small width. relative to the width L of the nonwoven web. The transport surface 2 is made of an electrically conductive material, and acts as a mass. The nonwoven webs W1, W2 (and indeed W3) consist of fibers forming a dielectric material. These are, for example, synthetic fibers based on polypropylene or polyethylene, and / or natural fibers of the cotton type, and / or artificial fibers of the viscose type.

Les ions négatifs générés par les moyens d'ionisation 4 permettant ainsi de charger électrostatiquement les bandes de non-tissé W2 et W3 en amont et an aval du rouleau de transfert 3, dans des zones longitudinales localisées de faible largeur (I) par rapport à la largeur L de la bande de non-tissé (les dimensions I et L sont mesurées dans la direction transversale CD perpendiculaire à la direction de transport de la bande de non-tissé). Ces zones longitudinales de maintien ZM de faible largeur I sont schématisées par des hachures sur la figure 2. Typiquement, la largeur I de la zone est de l'ordre de quelques centimètres ou dizaines de centimètres, et représente généralement moins de 1/10 de la largeur L de la bande de non-tissé.The negative ions generated by the ionization means 4 thus making it possible to electrostatically charge the strips of nonwoven W2 and W3 upstream and downstream of the transfer roller 3, in localized longitudinal zones of small width (I) with respect to the width L of the nonwoven web (the dimensions I and L are measured in the transverse direction CD perpendicular to the direction of transport of the nonwoven web). These longitudinal retention zones ZM of small width I are shown schematically by hatching on the figure 2 . Typically, the width I of the zone is of the order of a few centimeters or tens of centimeters, and generally represents less than 1/10 of the width L of the nonwoven web.

Dans l'application visée, ces zones de maintien ZM de faible largeur (I) s'étendent I latéralement (direction CD) au moins jusqu'aux bords longitudinal B de la bande de non-tissé (voir figure 3). Il en résulte que les lisières de la bande de non-tissé W2 adhèrent électrostatiquement à la surface de transport 2 depuis un point (figure 2/ abscisse X1) en amont de l'organe transfert 3 jusqu'à la région de réunification des bandes de non-tissé W1 et W2 (figure 2/ abscisse X2). En aval de la région de réunification des deux bandes de non-tissé W1 et W2, les lisières de la bande de non-tissé W3 adhèrent électrostatiquement à la surface de transport 2a jusqu'à une limite de maintien qui est située dans la direction de transport au-delà des champs ionisants générés (figure 2/ abscisse X3). En effet, une fois chargée, la bande de non-tissé W3 se décharge plus ou moins rapidement une fois qu'elle quitte le champ ionisant. Il en résulte une perte d'adhérence plus ou moins rapide en aval du champ ionisant généré. La position de la limite aval d'adhérence de la bande de non-tissé W3 (figure 2/ abscisse X3) dépend en pratique de plusieurs paramètres dont notamment : la puissance des champs ionisants ; la distance entre les moyens d'ionisation et la bande de non-tissé ; le matériau constitutif des fibres ou filaments du non-tissé ; la vitesse de transport.In the intended application, these narrow width ZM holding zones (I) extend laterally (direction CD) at least to the longitudinal edges B of the nonwoven web (see FIG. figure 3 ). As a result, the edges of the nonwoven web W2 electrostatically adhere to the transport surface 2 from a point ( figure 2 X1) upstream of the transfer member 3 to the region of reunification of the nonwoven webs W1 and W2 ( figure 2 / abscissa X2). Downstream of the region of reunification of the two strips of nonwoven W1 and W2, the selvedges of the non-woven web W3 electrostatically adhere to the transport surface 2a to a holding limit which is located in the transport direction beyond the generated ionizing fields ( figure 2 / abscissa X3). Indeed, once loaded, the nonwoven web W3 discharges more or less quickly once it leaves the ionizing field. This results in a more or less rapid loss of adhesion downstream of the generated ionizing field. The position of the downstream adhesion limit of the nonwoven web W3 ( figure 2 / abscissa X3) depends in practice on several parameters including: the power of ionizing fields; the distance between the ionization means and the nonwoven web; the constituent material of the fibers or filaments of the nonwoven; the speed of transport.

De préférence, dans l'application de la figure 1, on s'assure que la bande de non-tissé W3 adhère suffisamment à la surface de transport 2a au moins jusqu'au rouleau détour 2b, afin d'éviter un soulèvement ou retournement des lisières de la bande de non-tissé lors du changement de direction de transport (MD2 vers MD3).Preferably, in the application of the figure 1 it is ensured that the nonwoven web W3 adheres sufficiently to the transport surface 2a at least up to the detour roller 2b, in order to avoid raising or reversing the selvedges of the nonwoven web during the changeover. transport direction (MD2 to MD3).

Gràce à l'invention, on évite de manière simple et économique les problèmes de retournement des bandes de non-tissé dans les régions critiques de transport où elles sont susceptibles de subir des perturbations extérieures aérauliques et/ou mécanique (notamment région de transfert d'une bande d'une surface de transport à l'autre avec le cas échéant réunification avec une autre bande de non-tissé, région de changement de direction de transport de la bande de non-tissé).Thanks to the invention, it is possible to avoid in a simple and economical manner the problems of turning the non-woven webs in the critical transport regions where they are likely to undergo external air and / or mechanical disturbances (in particular transfer region of a strip from one transport surface to another with, where appropriate, reunification with another nonwoven web, transport direction change region of the nonwoven web).

En outre on évite avantageusement la mise en oeuvre de moyens d'aspiration pour le maintien du voile sur la ou les surfaces de transport, et de ce fait les inconvénients qui en découlent. Les surfaces de transport peuvent indifféremment être imperméables ou perméables l'air.In addition, it is advantageous to avoid the use of suction means for maintaining the veil on the transport surface or surfaces, and therefore the disadvantages that result therefrom. The transport surfaces can indifferently be impermeable or permeable to the air.

Dans le cas d'un maintien pendant le transport des lisières d'une bande de non-tissé, l'invention n'est pas limitée à un système permettant une réunification de voile. On peut utiliser l'invention uniquement lors d'un simple transfert d'une bande de non-tissé d'une surface de transport à l'autre, et par exemple, dans une configuration du type de la figure 1 lors du transfert de la bande de non-tissé W1 entre les surfaces de transport 1a et 2a, sans mise en oeuvre d'une bande de non-tissé W2. Dans ce cas, il n'est pas nécessaire de mettre en oeuvre des modules d'ionisation 4 en amont de l'organe de transfert 3. Egalement, on peut utiliser l'invention uniquement lors d'un simple transport d'une bande de non-tissé sur une surface de transport (sans transfert et sans réunification avec une autre bande de non-tissé), par exemple en supprimant dans la configuration de la figure 1 le convoyeur supérieur 1 et l'organe de transfert 3, et en conservant uniquement la surface de transport 2a, la bande de non-tissé W2 et tout ou partie des modules d'ionisation 4.In the case of a maintenance during the transport of the selvedges of a nonwoven web, the invention is not limited to a system allowing a reunification of sail. The invention may be used only at a simple transfer of a nonwoven web from one transport surface to another, and for example, in a configuration of the type of the figure 1 during the transfer of the nonwoven web W1 between the transport surfaces 1a and 2a, without using a web of nonwoven W2. In this case, it is not necessary to implement ionization modules 4 upstream of the transfer member 3. Also, the invention can be used only during a simple transport of a band of non-woven on a transport surface (without transfer and reunification with another non-woven web), for example by removing in the configuration of the figure 1 the upper conveyor 1 and the transfer member 3, and keeping only the transport surface 2a, the nonwoven web W2 and all or part of the ionization modules 4.

La solution qui vient d'être décrite trouve principalement (mais pas exclusivement) son application au transport d'une bande de non-tissé non consolidée et/ou d'une bande de non-tissé de faible poids, ce type de bande de non-tissé pouvant plus facilement être altérée par retournement de leurs lisères. Egalement, cette solution est plus particulièrement intéressante pour des vitesses de transport élevées (typiquement supérieures à 150 m/min), pour lesquelles les phénomènes de retournement des lisières sont amplifiés.The solution which has just been described finds mainly (but not exclusively) its application to the transport of an unbound nonwoven web and / or a nonwoven web of low weight, this type of non-woven web. -woven more easily be altered by flipping their edges. Also, this solution is more particularly advantageous for high transport speeds (typically greater than 150 m / min), for which the selvedge reversal phenomena are amplified.

2ème 2nd variante / Figures 4 à 6variant / Figures 4 to 6

La variante des figures 4 à 6 diffère de la variante des figures 1 à 3 qui vient d'être détaillée uniquement par le fait que les barres ionisantes 4a ont été remplacées par un moyen équivalent sous la forme d'une pluralité de pinceaux de ionisation 4b juxtaposés et sensiblement alignés selon l'axe principal d'ionisation 4c.The variant of Figures 4 to 6 differs from the variant of Figures 1 to 3 which has just been detailed only by the fact that the ionizing bars 4a have been replaced by equivalent means in the form of a plurality of ionization brushes 4b juxtaposed and substantially aligned along the main axis of ionization 4c.

Dans les variantes des figures 1 à 6, la largeur L des deux bandes de non-tissé W1 et W2 est sensiblement identique. Ceci n'est pas limitatif de l'invention, les largeurs des deux bandes de non-tissé W1 et W2 pouvant être différentes.In the variants of Figures 1 to 6 the width L of the two strips of nonwoven W1 and W2 is substantially identical. This is not limiting of the invention, the widths of the two strips of nonwoven W1 and W2 may be different.

2ème application : Découpe des lisières d'une bande de non-tissé 2nd application : Cutting selvedges of a nonwoven web

L'application des figures 7 et 8 concerne un système de découpe des lisières LI d'une bande de non-tissé W non consolidée, c'est-à-dire d'une bande de non-tissé dont les fibres constitutives n'ont pas encore subi d'opération de liage (thermique, chimique, hydraulique, mécanique) entre elles, et sont donc libres de glisser les unes par rapport aux autres. Ce système de découpe comporte :

  • une surface de transport 5a (telle que par exemple la bande 5a d'un convoyeur 5) permettant le transport d'une bande de non-tissé W dans la direction MD perpendiculairement à la largeur L de la bande de non-tissé,
  • deux barres ionisantes 4a fixes, positionnées sensiblement parallèlement à la direction transport (MD) et associées à deux buses 6 fixes de découpe par aspiration (une barre ionisante 4a et une buse 6 pour chaque lisière de la bande de non-tissé).
The application of figures 7 and 8 relates to a system for cutting the edges LI of a strip of nonwoven nonwoven W, that is to say a strip of nonwoven whose constituent fibers have not yet undergone binding operation (thermal, chemical, hydraulic, mechanical) between them, and are therefore free to slide relative to each other. This cutting system comprises:
  • a transport surface 5a (such as for example the belt 5a of a conveyor 5) for transporting a nonwoven web W in the MD direction perpendicular to the width L of the nonwoven web,
  • two stationary ionizing bars 4a, positioned substantially parallel to the transport direction (MD) and associated with two fixed vacuum cutting nozzles 6 (an ionizing bar 4a and a nozzle 6 for each edge of the nonwoven web).

Sur la figure 7, on a symbolisé par des hachures les deux champs ionisants ZI générés par les deux barres ionisantes 4a. Chaque barre ionisante permet de générer un champ ionisant ZI longitudinal d'axe principal d'ionisation 4c, à proximité et au-dessus de la bande de non-tissé W, de telle que sorte que les fibres de la bande de non-tissé adhèrent à la surface de transport 5 uniquement dans une zone de maintien longitudinale ZM de faible largeur I, par rapport à la largeur L de la bande de non-tissé.On the figure 7 the two ionizing fields ZI generated by the two ionizing bars 4a have been symbolized by hatching. Each ionizing bar makes it possible to generate a longitudinal ionization field ZI of main ionization axis 4c, near and above the nonwoven strip W, so that the fibers of the nonwoven strip adhere at the transport surface 5 only in a ZM longitudinal retention zone of small width I, with respect to the width L of the nonwoven web.

Les deux barres ionisantes 4a sont orientées de telle sorte que leur axe principal d'ionisation 4c est sensiblement parallèle à la direction de transport (MD) et sont positionnées au dessus de la bande de non-tissé et en retrait des bords longitudinaux B1 (avant découpe), de telle sorte que les deux zones de maintien électrostatique ZM sont espacées selon la direction transverse CD d'une distance (e) inférieure à la largeur L de la bande de non-tissé et surtout ne s'étendent pas jusqu'aux bords longitudinaux B1 de la bande (avant découpe).The two ionizing bars 4a are oriented so that their main ionization axis 4c is substantially parallel to the transport direction (MD) and are positioned above the nonwoven strip and set back from the longitudinal edges B1 (before cutting), so that the two electrostatic holding zones ZM are spaced in the transverse direction CD by a distance (e) less than the width L of the non-woven strip and especially do not extend to longitudinal edges B1 of the strip (before cutting).

En référence à la figure 7, la buse 6 de découpe par aspiration comporte une ouverture d'aspiration 6a qui est positionnée au-dessus de la lisière LI de la bande à retirer et est orientée vers ladite lisière, et des moyens d'aspiration (ventilateur) permettant de créer à travers ladite ouverture 6a, un flux d'air perpendiculaire à la surface de transport 5a (figure 7/ flèches F). L'ouverture d'aspiration s'étend dans la direction transverse CD depuis sensiblement la frontière longitudinale extérieure 4d du champ d'ionisation ZI jusqu'au moins le bord longitudinal B1 (avant découpe) de la bande de non-tissé W. Sensiblement au droit de la frontière longitudinale extérieure 4d du champ de ionisation ZI , la buse 6 de découpe par aspiration est équipée d'une tôle verticale 6c (figure 3) permettant de mieux confiner le flux d'aspiration F en dehors du champ ionisant (ZI).With reference to the figure 7 the vacuum cutting nozzle 6 has a suction opening 6a which is positioned above the edge LI of the strip to be removed and is directed towards said selvedge, and suction means (fan) for creating through said opening 6a a flow of perpendicular to the transport surface 5a ( figure 7 / arrows F). The suction aperture extends in the transverse direction CD from substantially the outer longitudinal boundary 4d of the ionization field ZI to at least the longitudinal edge B1 (before cutting) of the nonwoven web W. right of the external longitudinal boundary 4d of the ionization field ZI, the vacuum cutting nozzle 6 is equipped with a vertical plate 6c ( figure 3 ) to better confine the suction flow F outside the ionizing field (ZI).

En fonctionnement, les barres ionisantes 4a et les buses 6 de découpe par aspiration sont actives, et la surface de transport 5a fait défiler la bande de non-tissé dans la direction de transport MD, au dessous des barres ionisantes 4a et buses 6. Au droit de chaque buse d'aspiration, les fibres constitutives de la partie extérieure de la bande de non-tissé W correspondant à une lisière LI n'adhèrent pas (ou très peu) à la surface de transport 5a. Ces fibres sont donc très facilement retirées par aspiration et évacuées par chaque buse 6. A l'inverse, les fibres de la bande de non-tissé, qui jouxtent la buse d'aspiration 6 mais qui sont situées dans le champ ionisant ZI, adhèrent fortement à la surface de transport 5a, ce qui permet avantageusement d'obtenir un maintien parfait de la bande de non-tissé contre la surface de transport 5a pendant l'opération de découpe par aspiration des lisières LI.In operation, the ionizing bars 4a and the suction cutting nozzles 6 are active, and the transport surface 5a scrolls the nonwoven web in the transport direction MD, below the ionizing bars 4a and nozzles 6. At right of each suction nozzle, the constituent fibers of the outer portion of the nonwoven web W corresponding to an edge LI do not adhere (or very little) to the transport surface 5a. These fibers are thus very easily removed by suction and discharged by each nozzle 6. In contrast, the fibers of the nonwoven web, which adjoin the suction nozzle 6 but which are located in the ionizing field ZI, adhere strongly to the transport surface 5a, which advantageously allows to obtain a perfect retention of the nonwoven web against the transport surface 5a during the cutting operation by suction edges LI.

En aval des buses de découpe par aspiration 6, on obtient une bande de non-tissé W dont les bords B2 sont plus rectilignes que les bords B1 de la bande avant découpe des lisères LI. En outre, la largeur de la bande de non-tissé est parfaitement calibrée.Downstream of the suction cutting nozzles 6, there is obtained a strip of nonwoven W whose edges B2 are more straight than the edges B1 of the strip before cutting LI edges. In addition, the width of the nonwoven web is perfectly calibrated.

Bien entendu, les barres ionisantes 4a pourraient être remplacées par tout moyen d'ionisation équivalent, et par exemple par une pluralité de dispositifs ionisants, du type des pinceaux ionisants décrits dans la première application précitée, sensiblement alignés selon la direction de transport MD. Dans une autre variante de réalisation, les barres ionisantes 4a pourraient également être légèrement inclinées d'un angle A par rapport à la direction de transport MD.Of course, the ionizing bars 4a could be replaced by any equivalent ionization means, and for example by a plurality of ionizing devices, of the type of ionizing brushes described in the first application above, substantially aligned in the MD transport direction. In another variant embodiment, the ionizing bars 4a could also be slightly inclined at an angle A with respect to the transport direction MD.

On a représenté sur la figure 9, une autre variante de réalisation, dans laquelle le module d'ionisation 4 est constitué par deux barres ionisante 4a alignées selon la direction transversale CD. Ainsi, l'axe d'ionisation principale 4c du module d'ionisation 4 s'étend sensiblement perpendiculairement à la direction de transport (MD), l'essentiel dans cette application (de même que dans l'application ci-après de la figure 10) étant que la ou les zones de maintien électrostatique ZM ne s'étendent pas jusqu'aux bords longitudinaux B1 (avant découpe) de la bande de non-tissé W.We have shown on the figure 9 , another variant embodiment, in which the ionization module 4 is constituted by two ionizing bars 4a aligned in the transverse direction CD. Thus, the main ionization axis 4c of the ionization module 4 extends substantially perpendicular to the direction of transport (MD), the essential in this application (as well as in the application below of the figure 10 ) being that the electrostatic holding zone (s) ZM do not extend to the longitudinal edges B1 (before cutting) of the nonwoven web W.

3ème application : Découpe avec profilage des lisières d'une bande de non-tissé 3rd Application: Cutting with profiling of the edges of a strip of non-woven

L'application de la figure 10 concerne un système découpe par aspiration avec profilage des lisières LI d'une bande de non-tissé W non consolidée.The application of the figure 10 relates to a vacuum cutting system with LI edge profiling of an unbound nonwoven web W.

Le système se différencie des systèmes de découpe précités des figures 7 à 9 uniquement par la position latérale de chaque buse 6 dans la direction transverse CD. En référence à la figure 10, une partie de l'ouverture d'aspiration 6a est disposée dans le champ ionisant ZI (c'est-à-dire au droit des fibres qui adhèrent à la surface de transport 5) et l'autre partie de l'ouverture d'aspiration 6a est disposée en dehors du champ ionisant ZI.The system differs from the above-mentioned cutting systems Figures 7 to 9 only by the lateral position of each nozzle 6 in the transverse direction CD. With reference to the figure 10 a portion of the suction opening 6a is disposed in the ionizing field ZI (i.e. at the fibers adhering to the transport surface 5) and the other part of the opening of the suction 6a is disposed outside the ionizing field ZI.

En fonctionnement, une partie seulement des fibres qui se trouvent dans le champ ionisant ZI et au droit de l'ouverture d'aspiration 6a sont aspirées, la quantité de fibres retirées augmentant en direction de la frontière 4d du champ ionisant ZI. Au-delà de cette frontière 4d (en direction du bord longitudinal de la bande de non-tissé), comme pour le système de découpe précité, toutes les fibres qui n'adhèrent pas ou très peu à la surface de transport 5, sont aspirées bar la buse 6. On obtient ainsi, en aval des buses d'aspiration 6, une bande de non-tissé dont les lisières LI présentent un profil aminci (profil en biseau), tel que par exemple celui représenté sur la zone d'agrandissement de la figure 10.In operation, only part of the fibers in the ionizing field ZI and the right of the suction opening 6a are sucked up, the amount of fibers removed increasing toward the boundary 4d of the ionizing field ZI. Beyond this boundary 4d (towards the longitudinal edge of the nonwoven web), as for the aforementioned cutting system, all the fibers that do not adhere or very little to the transport surface 5, are sucked bar nozzle 6. Thus, downstream of the suction nozzles 6, a strip of non-woven whose edges LI have a profile thinned (profile bevel), such as for example that represented on the enlargement area of the figure 10 .

Cette solution technique de profilage des lisières d'un non-tissé non consolidé est particulièrement utile en voie nappée, c'est-à-dire dans toutes les applications où la bande de non-tissé non consolidée W alimente un étaleur-nappeur en vue de former une nappe de non-tissé par retournement et repliement sur elle-même de la bande de non-tissé.This technical solution for profiling the edges of a non-woven non-woven fabric is particularly useful in the nap, that is to say in all applications where the non-woven non-woven web W feeds a crosslapper in order to forming a nonwoven web by turning and folding the nonwoven web around itself.

Dans les exemples des figures annexées, les surfaces de transport sont planes. Ceci n'est pas limitatif de l'invention. Dans d'autres applications de l'invention, les surfaces de transport peuvent être courbes, et notamment cylindriques.In the examples of the attached figures, the transport surfaces are flat. This is not limiting of the invention. In other applications of the invention, the transport surfaces may be curved, and in particular cylindrical.

Dans les variantes de réalisation qui ont été décrites en référence aux figures annexées, l'adhérence de la bande de non-tissé sur la surface de transport est obtenue en chargeant électrostatiquement la bande de non-tissé. Ceci n'est pas limitatif de l'invention. Dans d'autres variantes de réalisation de l'invention, on peut obtenir le même effet d'adhérence, en chargeant électrostatiquement uniquement la surface de transport. Egalement, dans d'autres variantes de réalisation de l'invention, on peut obtenir le même effet d'adhérence, en chargeant électrostatiquement à la fois la surface de transport et la bande de non-tissé, mais avec des polarités opposées.In the embodiments which have been described with reference to the accompanying figures, the adhesion of the nonwoven web to the transport surface is obtained by electrostatically charging the nonwoven web. This is not limiting of the invention. In other embodiments of the invention, the same adhesion effect can be obtained by electrostatically charging only the transport surface. Also, in other embodiments of the invention, the same adhesion effect can be obtained by electrostatically charging both the transport surface and the nonwoven web, but with opposite polarities.

Claims (23)

  1. A method of transporting at least one non-woven web (W2; W3; W), using a mobile transport surface (2a, 5a), characterized in that the non-woven web and/or the transport surface (2a; 5a) are electrostatically charged so as to make the non-woven web adhere electrostatically on the transport surface in at least a first maintenance zone (ZM) whereof the dimension (I) measured in the direction (CD) perpendicular to the transport direction (MD) is smaller than the width (L) of the non-woven web.
  2. The method according to claim 1, characterized in that the non-woven web and/or the transport surface are electrostatically charged so has to make the non-woven web electrostatically adhere on the transport surface in at least one second maintenance zone (ZM), whereof the dimension (I) measured in the transverse direction (CD) perpendicular to the transport, direction (MD) is smaller than the width (L) of the non-woven web, and which is positioned at the first maintenance zone (ZM) in the transverse direction (CD) perpendicular to the transport direction (MD) and is spaced away from the first maintenance zone by a distance (e) measured in said transverse direction (CD).
  3. The method according to one of claims 1 or 2, characterized in that each maintenance zone (ZM) extends in the transverse direction (CD) up to the longitudinal edge (B) of the non-woven web (W2; W3).
  4. The method according to claim 3, characterized in that a first non-woven web (W1) is transported using a first transport surface (1a) up to a second transport surface (2a), in that the first non-woven web (W1) is transferred on said second transport surface, in that said first non-woven web (W1) is transported using the second transport surface, and in that each maintenance lone (ZM) is created immediately downstream of the transfer region between the first (1a) and second (2a) transport surface.
  5. The method according to claim 4, characterized in that the second transport surface (2a) is used to transport a second non-woven web (W2) that has been deposited on the second transport surface upstream of the transfer zone of the first non-woven web (W1), such that the first non-woven web (W1) is transferred on the second non-woven web so as to form, with said second web, a third non-woven web (W3), and in that at least two additional maintenance zones (ZM) are created by electrostatically charging the second non-woven web (W2) and/or the second transport surface (2a) upstream of the transfer region so as to make the second non-woven web (W2) electrostatically adhere of the second transport surface (2a) upstream of the first non-woven web (W1) transfer region, the width (I) of each upstream maintenance zone (ZM) measured in the direction (CD) perpendicular to the transport direction being smaller than the width (L) of the second non-woven web, and the two upstream maintenance zones (ZM) extending respectively up to the two longitudinal edges (B) of the second non-woven web (W).
  6. The method according to one of claims 4 or 5, characterized in that the transfer of the first non-woven web (W1) on the second transport, surface (W2) is done using a rotary transfer member (3), preferably with suction.
  7. The method according to claim 1 or 2, characterized in that each maintenance zone (ZM) is created near a longitudinal edge (B1) of the non-woven web (W) but does not extend laterally in the transverse direction (CD) up to said longitudinal edge (B1).
  8. The method according to claim 7, characterized in that a working area that is located along the transport direction (MD) at a position between the beginning and the end of an electrostatic maintenance zone (ZM), an action is exerted on the selvedge (LI) of the non-woven web.
  9. The method according to claim 8, characterised in that said action consists of cutting the selvedge (LI).
  10. The method according to claim 8, characterized in that the action consists of removing part of the fibers from the selvedge (LI) so as to give it a thinner profile.
  11. The method according to claim 9 or 10, characterized in that said action exerted on the selvedge (LI) of the non-woven web is done via suction.
  12. The method according to one of claims 1 to 11, characterized in that it is implemented on at least one unconsolidated non-woven web.
  13. A system for transporting at least one non-woven web comprises at least one surface (2a; 5a) for transporting the non-woven web (W2; W3; W), and at least one ionization module (4), characterized in that said ionization module makes it possible to locally generate an ionizing field (ZI) that does not extend to the longitudinal edges (B) of the non-woven web (W).
  14. The system according to claim 13, characterized in that an ionization module comprises an ionizing strip (4a) and/or a plurality of ionization device (4b) substantially maligned along the main ionization axis (4c).
  15. The system according to claim 13 or 14 for maintaining the salvedges of a non-woven web, characterized in that the main ionization axis (4c) of each ionization module (4) is inclined by an angle (A) smaller than 45° relative to the transport direction (MD2) of the non-woven web (W2, W3).
  16. The system according to one of claims 13 to 15, characterized in that it includes a first transport surface (1a) and a second transport surface (2a), the first transport surface making it possible during operation to convey a non-woven web (W1) to the second transport surface (2a), and in that it has two ionization modules (4) arranged downstream of the transfer region between the two transport surfaces, and spaced apart from each other along a transverse direction (CD) perpendicular to the transport direction (MD2).
  17. The system according to claim 16, for reunifying two non-woven webs (W1, W2) by superposition thereof, characterized in that it includes two ionization modules (4) arranged upstream of the transfer region between the two transport surfaces, and spaced apart from each other in a transverse direction (CD) perpendicular to the transport direction (MD).
  18. The system according to claim 16 or 17, characterized in that it includes a rotary transfer member (3) inserted between the two transport surfaces (1a, 2a).
  19. The system according to claim 13 or 14, characterized in that it includes a suction means (6) associated with an ionization module and allowing cutting out by suction of at least one selvedge (LI) of a non-woven web.
  20. The system according to claim 19, characterized in that the suction means (6) has a suction opening (6a) positioned at the border of and outside the ionization field (ZI) of the associated ionization module (4).
  21. The system according to claim 19, characterized in that the suction means (6) has a suction opening (6a) positioned partially in the ionization field of the ionization module (4) so as to allow cutting out with profiting of the selvedge (LI) of a non-woven web.
  22. The system according to one of claims 19 to 21, characterized in that the main ionization axis (4c) of each ionization module (4) is substantially parallel to the transport direction (MD).
  23. The system according to any one of claims 13 to 22, said at least one ionization module (4) making it possible to locally generate a longitudinal ionizing field (ZI) with a small width and having a main ionization axis (4c) oriented essentially in the transport direction (MD2; MD) of the non-woven web.
EP06370005A 2005-03-18 2006-03-06 Verfahren und Vorrichtung zum Transportieren einer Bahn nichtgewebten Materials mit elektrostatischer Aufladung in mindestens einer Zone mit einer Dimension die kleiner als die Breite der Bahn ist Active EP1702874B8 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR0502675A FR2883267B1 (en) 2005-03-18 2005-03-18 METHOD AND SYSTEM FOR TRANSPORTING A NON-WOVEN STRIP WITH ELECTROSTATIC RETENTION IN AT LEAST ONE AREA OF SIZE LESS THAN THE WIDTH OF SAID STRIP

Publications (4)

Publication Number Publication Date
EP1702874A2 EP1702874A2 (en) 2006-09-20
EP1702874A3 EP1702874A3 (en) 2007-05-30
EP1702874B1 true EP1702874B1 (en) 2011-07-27
EP1702874B8 EP1702874B8 (en) 2012-02-29

Family

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EP06370005A Active EP1702874B8 (en) 2005-03-18 2006-03-06 Verfahren und Vorrichtung zum Transportieren einer Bahn nichtgewebten Materials mit elektrostatischer Aufladung in mindestens einer Zone mit einer Dimension die kleiner als die Breite der Bahn ist

Country Status (3)

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EP (1) EP1702874B8 (en)
CN (1) CN1834324B (en)
FR (1) FR2883267B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2892110B1 (en) * 2005-10-19 2009-01-16 Asselin Thibeau Soc Par Action METHOD AND ASSEMBLY FOR FORMING A MULTILAYER NON-WOVEN STRIP WITH ELECTROSTATIC RETENTION OF SAID NON-WOVEN STRIP
DE102010004205B4 (en) 2010-01-08 2012-11-08 Fecken-Kirfel Gmbh & Co. Kg Apparatus and method for splitting foam bodies

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CH659035A5 (en) * 1980-05-06 1986-12-31 Walter Spengler METHOD FOR GATHERING BUNCHES OF ELECTRICALLY INSULATING BOW-SHAPED SUBSTRATE MATERIALS FOLDED.
FR2667267A1 (en) * 1990-09-27 1992-04-03 Mira Sarl Electrostatic assistance device for the design of book sections, exercise books or the like
DE29723999U1 (en) * 1997-04-02 1999-12-09 Eltex-Elektrostatik Gmbh, 79576 Weil Am Rhein Electrostatic charging device
DE20101202U1 (en) * 2000-05-16 2001-05-10 Spengler Electronic Ag, Biel-Benken Device for combining at least two paper webs into one paper strand
FR2815646B1 (en) * 2000-10-20 2003-01-10 Rieter Perfojet INSTALLATION FOR PRODUCING A NONWOVEN TABLECLOTH FROM WHICH THE DIFFUSER IS REMOTE FROM THE DRAWING SLOT DEVICE
DE10140864A1 (en) * 2001-08-21 2003-03-06 Truetzschler Gmbh & Co Kg Device for needling a conveyable nonwoven fabric
EP1507725B1 (en) * 2002-05-17 2007-05-30 Polymer Group, Inc. Conveyor for inverting web of material

Also Published As

Publication number Publication date
CN1834324A (en) 2006-09-20
EP1702874B8 (en) 2012-02-29
EP1702874A3 (en) 2007-05-30
CN1834324B (en) 2012-04-25
FR2883267B1 (en) 2007-06-08
EP1702874A2 (en) 2006-09-20
FR2883267A1 (en) 2006-09-22

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