ES2262025T3 - PROCEDURE AND DEVICE FOR STABILIZING THE EDGES OF AN UNWATCHED VEIL. - Google Patents

Abstract

A method for stabilizing the edges (B, B') of a nonwoven web (V) on a movable support surface (3), wherein the web is obtained by continuous carding and spinning (A) of long fibers (Fl) and by subsequently laying short fibers (Fc) on the web (V) which is driven on the movable support surface. As the short fibers (Fc) are laid thereon, the side edges (B, B') of the web (V) are at least partly covered and compressed against the movable support surface (3), so that in such area short fibers (Fc) are prevented from being laid along the edges, whose stability is thereby increased, by preventing rolling or folding thereof. The covering and compressing action is exerted on the longitudinal edges of the web over a length corresponding at least to the short fiber laying area, and over a transverse width which is predetermined by using a pair of plates (10, 10') which are designed to cover the edges (B, B') and are at least partly in contact with the movable support surface (3).

Description

Procedure and device to stabilize the edges of a non-woven veil.

Technical field

The present invention relates to a procedure to stabilize the edges of a nonwoven veil, according to the preamble of claim 1.

The invention also relates to a device to implement the procedure, as well as the non-woven veil, obtained using said procedure and said apparatus.

Prior art

The procedures and the manufacturing facilities for nonwoven fabrics, comprising at least one stage of preparing a support veil formed by middle of a layer or blanket of long fibers, a stage of, so less, an extended tuft of short fibers or pulp of wood on it, and at least one stage of gluing the short fibers with each other and with the preformed veil on which they have been extended, to provide the nonwoven fabric obtained from This shape with the desired consistency.

The preformed blanket or veil is composed of long fibers and can be obtained by an operation of carding, that is, using a carding machine or by continuous centrifugation, that is, using the so-called machines spinning

Wood pulp or short fibers they are usually transported and spread over the preformed veil of long fibers by the pneumatic action of some machines that they are known in the art as "spreading machines by air".

The gluing of the fibers can be achieved by a thermal process, that is, by partial fusion and welding at the fiber contact points, or by means of a chemical process, that is, by partial fusion and welding by a solvent that later evaporates, or also by a mechanical procedure, that is, weaving the fibers using high pressure liquid jets.

Typically, for this last operation you uses water, which is generally known to those skilled in the art known as "hydro-tangled".

In a known procedure and installation, a veil of long fibers, prepared by carding or spinning, is first coated with a layer of short fibers and to continuation with another veil of long carded or spinning fibers. The set is subsequently glued by a treatment thermal or by hydro-matting.

According to other procedures, the fiber layer Short is spread over a layer of long fibers since glued and then joined by another operation of hydro-matted.

Depending on the desired type of nonwoven fabric, These operations are combined and / or repeated.

A drawback of said procedures of the prior art involves the difficulty of controlling the edges of the veil when the short fibers extend, due to the aerodynamic turbulence generated next to the edges of the tape conveyor by the pneumatic extension unit, whose turbulence causes the veil to bend and brown, generating with it irregular edges and defects in the final product.

This inconvenience increases with increasing speed of advance of the veil and consequently the installation productivity.

An additional drawback lies in the presence of wood pulp at the edges of the veil, must be said pulp removed before gluing, for example by means of a localized aspiration. This aspiration cannot be controlled. easily since the long fibers of the preformed veil or blanket They also tend to be aspirated.

These fibers, different in nature and Pulp length extended above, tend to clog and dirtying the transport system and the fiber extension short to which the aspirated fibers are conducted, and this affects negatively the correct operation of said system.

Also, the wood pulp of the edge of the veil quickly dirties the hydro-matted machine and the consequent defects in the finished product as well as the need for more frequent cleaning and work of machine maintenance

Summary of the invention

A general objective of this invention is to obviate the above drawbacks disclosing a procedure for the manufacture of nonwoven fabrics, which allows to obtain a non-woven fabric uniform knitting, as described above, of a reliable and economical way, even with speeds and some high production advances.

An additional objective is to devise a procedure Spread of short fibers that reduces fabric defects not woven especially on the edges of it.

Still another goal is to publicize a Short fiber spreading procedure that allows adjustment easily extracting the excess of short fibers extended in The edges of the veil.

Another objective is to publicize a procedure of extended short fibers that allows to recover the fibers short or the wood pulp that have been aspirated without the presence of long fibers of the preformed blanket or veil.

An additional objective is to publicize a manufacturing process of non-woven fabrics that can work continuously and with high productivity.

These and other objectives, which will be understood more easily then they are achieved by a procedure for stabilizing the edges of a nonwoven veil, according to the claim 1, wherein the fabric is obtained by carding or continuous spinning of long fibers, spreading them over a mobile support surface with forward speed default to form a veil with side edges substantially straight, subsequently extending a layer of short fibers on said veil, gluing said fiber layer cut with said veil to form the nonwoven fabric, characterized because before extending the short fibers, the lateral edges of the veil are at least partially protected and compressed against the mobile support surface.

Thanks to this procedure it is possible to avoid that the short fibers be extended along the edges of the Veil and eliminate any aerodynamic turbulence, as well as increase stability and avoid curls or folds, without taking counts the feed rate and length of the long fibers that They have been extended.

According to an additional aspect of the present invention, a stabilization device of the edge for a non-woven veil for the implementation of the previous procedure, suitable to be mounted in a unit of extended short fiber array arranged below a station continuous spinning of long fiber veil, whose veil is fed on a mobile support surface, whose device, according to the claim 9, characterized in that it comprises means to protect and compress the longitudinal edges of the veil in the extended area of short fibers, so that they prevent the fibers are extended along said edges and to increase the stability of the veil, thus avoiding any curl or fold of it.

The device of the present invention allows prevent wood pulp or short fibers from spreading on the edges of the veil, thus avoiding disadvantages of pollution and fiber accumulation you cut in the next machine to mechanically join the veil by high pressure water jets.

Brief description of the drawings

From the detailed description of a procedure and a device for edge stabilization from a non-woven fabric other ones will be more clearly understood characteristics and advantages of the invention, which are described by way of non-limiting example with the help of the drawings Attachments, in which:

Figure 1 shows a flow chart of the method of the invention;

Figure 2 is a schematic side view of a device for implementing the procedure of the invention;

Figure 3 is a schematic front view of the device of Figure 2;

Figure 4 is a schematic view in installation of the device of Figure 2;

Figure 4a is a sectional view of a isolated and enlarged detail of Figure 4, taken along a axis IV-IV;

Figure 5 is a schematic side view of the detail of the device for the implementation of the procedure of the invention;

Figure 6 is a schematic front view of the device of Figure 5.

Detailed description of various embodiments exemplary

Referring to the mentioned figures previously, a process for manufacturing a non-woven fabric T, it generally comprises a stage A in which the long fibers F_l are continuously carded or centrifuged, a stage B in which said fibers are uniformly extended to form a blanket or veil V, with a substantially uniform thickness and about substantially straight longitudinal side edges B, B '.

This stage is followed by stage D in which a layer of short fibers F c, possibly comprising pulp of wood, it is extended above the veil V.

Finally, stage E is carried out in which the short fibers F_ are joined to the long fibers F_ of the veil V to form the nonwoven fabric T.

Particularly, the short fibers F_ {c} they can be extended using air, according to a procedure known per se by those skilled in the art as "air spread procedure" while the stage of E junction can be carried out using water jets at high pressure according to the technique of hydro-entangled.

Suitably, the long fibers F_ {l} that form the carded veil V can be extended above a mobile support surface, for example a conveyor belt which is driven at a predetermined speed S.

According to the invention, before stage D of extended of the short fibers F c, the longitudinal edges B, B 'of veil V are subjected to stage C in which the long fibers F_ {l} are protected and compressed along the surface of the conveyor belt 3, to increase stability and adhesion of these parts of the veil and prevent them from bending or curly

Suitably, protection and compression C it is exerted on the longitudinal edges B, B 'of the veil on a length that corresponds at least to the extended area of short fibers, and over a predetermined transverse width W.

Experimentally it was found that veil edges V were adequately stabilized with a variable width W of the protection and compression zones between 10 and 100 mm.

Advantageously, the compression exerted on the edges B, B 'can be adjusted according to the type of veil W, in a way that allows a free advance of it.

In addition, the excess of short fibers F c is Aspires on the conveyor, once extended on the veil, at a predetermined distance from the edges B, B ', outside of the edge coverage and compression zone to prevent the long fibers F_ {l} of the veil V are aspirated and transported back to the fiber extension unit.

This prevents soiling and clogging of the shot. of admission of short fibers and the extension unit itself.

Referring below to the figures attached, a device 1 for carding or spinning and for extend the long fibers F_ {l} to form a veil V, is arranged before a unit 2 extending the short fibers F_ {c} using air, to prepare a non-woven fabric T.

The device 1 for the treatment of long fibers F l comprises a carding or spinning unit (not shown) and a unit for extending long fibers F_ {l} on a mobile support surface. The latter is, for example, a conveyor belt 3 that extends between the rollers ends 4, 5.

Unit 2, extended from short fiber F_ {c,} is located downstream of device 1 and can use the same conveyor belt 3.

According to the invention, the spreading device 2 comprises means to protect and compress the edges lengths of the veil, designated globally as 6, 6 ', arranged in the extended area of the short fiber Fc, to avoid that the short fibers be extended along the edges B, B ' and to increase the stability of the veil V, thus avoiding any curly or fold it in these areas.

In particular, the means of protection and compression 6, 6 'are arranged on the tape 3, along the 2 short fiber spreading unit, to protect and compress the edges of said veil against the surface of the tape 3.

Preferably, the protection means and compression 6, 6 'are removably attached to unit 2 of extended of the short fiber, by means of connection means suitable 7, which can be regulated at distances transverse variables to adapt to the width of the veil V.

In particular, the connection means 7 they comprise regulation means 8, 9 for controlling the pressure over those edges.

In the embodiment represented in the figures, the protection and compression means 6, 6 'comprise a pair of longitudinal plates 10, 10 'having parts curved ends 11, 12, 11 ', 12' delimiting springs of torsion fixed to the adjustment means 8, 9.

The adjustment means 8, 9 may comprise pins 14, 14 ', 15, 15' for the twisting of the end parts 11, 12, 11 ', 12' of sheets 10, 10 '. You can make the spikes 14, 14 ', 15, 15' turn from the outside by any means not represented, to provide some torsion moments that act on substantially vertical planes to the end portions 11, 12, 11 ', 12' of plates 10, 10 '.

Suitably, the plates 10, 10 'are made of an elastic metallic material, in particular of steel, or of a reinforced or composite plastic material.

The device also includes means 16, 16 'for the aspiration of excess short fibers extended over the mobile support surface, said means being able to consist of suction in intake jacks 16 located on the sides opposite of the movable support surface 3, outside the edge B, B ' of the area of coating and compression.

The suction means 16, 16 'can present connected by suitable pipes, not shown in the drawings, to the short fiber spreading unit 2 for make excess pulp or fiber circulate back to this area short Fc.

Advantageously, the plates 10, 10 'can have an amplitude such that it covers the edges B, B 'with a minimum transverse width W of 10 to 100 mm, thus preventing Short fibers are spread over it.

Appropriately, the leaves have an amplitude transverse (H) greater than at least 10 mm. This allows the use of sockets 16, 16 'in such a way that the risk of aspirating carded fibers or continuous filaments together with Short fibers, whose fibers and filaments could be sent also to the short fiber spreading unit 2 and make said unit and the ground wood pulp chips remain clogged, creating serious mechanical problems and Installation interruptions for maintenance.

Appropriately, according to the invention, the machine for manufacturing the non-woven fabric T with the edges stabilized comprises a spinning station of a continuous veil of long fibers 1, followed by a fiber extension unit 2 cut comprising a device for stabilizing the edge of the veil.

This provides an increase in stability. of the veil, prevents the formation of wrinkles and folds at the edges and counteract any movement generated by turbulence produced by the air spreader unit.

This installation combines high speed Manufacturing with high quality manufactured fabric.

As a result, the non-woven fabric T with the stabilized edges that you get using a device like the one described above, comprises a veil V of long fibers carded or spinning F_ {l}, on which a layer is superimposed of short fibers F_, interwoven with the long fibers of the veil V, whose edges B, B 'do not contain short fibers F_ {c}, and are continuous, straight and have no folds or curls, or residues of process.

From the above description, it follows that the procedure and the edge stabilization device of the nonwoven fabric according to the present invention and as it has been claimed in the appended claims, allows to reach the intended objectives and particularly obtain a non-woven fabric uniform in a reliable and economical way, even at high forward speeds and at a high manufacturing rate, thereby minimizing the defects of the final product, especially at the edges of it.

In addition, said procedure and said device allow to prevent short fibers from being extended at the edges of the veil, thus preventing the obstruction of the units for the fiber recycling.

The procedure and the device according to this invention are susceptible to numerous modifications and changes, all of them being included within the given inventive concept to be known in the claims. All the details of them they can be replaced by other technical equivalents, and the Materials may vary depending on the different needs without departing from the field of the invention.

While the objective of the invention has been described with particular reference to the figures that accompany, the reference numbers mentioned in the exhibition and in the claims they are used only for a better understanding of the invention and are not intended to limit any It forms the claimed field.

Claims (20)

1. Procedure for stabilizing the edges of a non-woven veil, in which the fabric (A) is obtained by continuous carding or spinning of long fibers (F_), extending (B) said long fibers (F_ {l} ) on a movable support surface (3), with a predetermined feed rate (S) to form a veil (V) with substantially straight side edges (B, B ') extending (C) a layer of short fibers (F_ {c}) on said veil (V) joining (E) said short fiber layer (F_) with said veil (V) to form the nonwoven fabric, characterized in that before extending (C) the short fibers, the lateral edges (B, B ') of the veil (V) are at least partially protected and compressed against the movable support surface (3) to prevent short fibers from being extended in said areas and to eliminate any aerodynamic turbulence, thus as to increase stability and prevent curls or folds in the fabric along its edges (B, B ') without having in it counts the speed of advance and the length of the long fibers that have been extended. 2. Method according to claim 1, characterized in that the protection and compression action is exerted along the longitudinal edges (B, B ') of the veil (V) over a length corresponding to at least the area of Extended short fibers. Method according to claim 1, characterized in that the protection and compression action is exerted along the longitudinal edges (B, B ') of the veil over a predetermined minimum transverse width (W). Method according to claim 1, characterized in that the protection and compression action on the edges (B, B ') is exerted by a pair of longitudinal plates (10, 10') resting on said edges (B, B ' ) in contact with the conveyor belt, without preventing the free advance of the veil (V). 5. Method according to claim 3, characterized in that said predetermined minimum transversal width of protection and compression (W) is between 10 and 100 mm. Method according to claim 4, characterized in that the pressure of said plates (10, 10 ') against the mobile support surface (3) can be regulated by changing the pressure exerted along said edges, depending on the type of the veil Method according to claim 4, characterized in that the excess of short fibers on said mobile support surface (3) is removed by aspiration, downstream of said short fiber extension zone, outside the edges (B, B ') of the veil, substantially aligned with said protection and compression plates (10, 10 ') to prevent long veil fibers (V) from being aspirated as well. Method according to one or more of the claims, characterized in that said short fibers comprise wood pulp. 9. Device for stabilizing the edges (B, B ') of a nonwoven web, for practicing the method according to one or more of the preceding claims, said device being applicable to a short fiber spreading unit (2), arranged downstream of a station for continuous spinning of a long fiber veil (V), actuated on a movable support surface (3), the device being characterized in that it comprises means (6, 6 ') for protecting and compressing the longitudinal edges of the veil in the area of extension of the short fibers so as to prevent them from being extended along said edges and to increase the stability of the veil, thus avoiding any curl or crease therein. Device according to claim 9, characterized in that said protection and compression means (6, 6 ') are arranged on said belt along said unit to compress the fibers of said veil against said mobile support surface (3). Device according to claim 10, characterized in that said protection and compression means (6, 6 ') are removably fixed in said short fiber spreading unit (2) by means of appropriate connection means (7). 12. Device according to claim 11, characterized in that said connection means (7) are arranged at an adjustable transverse distance to adapt them to the width of the veil (V). 13. Device according to claim 11, characterized in that said connection means (7) comprise regulating means for controlling the pressure exerted on said edges. 14. Device according to claim 11, characterized in that said protection and compression means (6, 6 ') comprise at least one pair of longitudinal plates (10, 10') with curved end portions delimiting torsion springs with a terminal subject to said regulation means. 15. Device according to claim 14, characterized in that said plates have a transverse width (H) of at least greater than 10 mm. 16. Device according to claim 14, characterized in that said regulating means comprise pins (8, 9) for rotating the end portions (11, 12) of said plates (10, 10 '), said pins being adapted (8, 9) to transmit torsional moments acting in substantially vertical planes to said parts. 17. Device according to claim 14, characterized in that said sheets (10, 10 ') are made of an elastic material such as steel or a synthetic elastic material such as reinforced plastic. 18. Device according to claim 9, characterized in that it comprises means (16) for the aspiration of the excess of short fibers on said mobile support surface (3), said aspiration means being constituted at least in a pair of sockets (16 ) located on opposite sides with respect to said movable support surface (3), at a predetermined distance from said edges (B, B ') substantially aligned with said protection and compression sheets (6, 6') to prevent the fibers veil lengths are also aspirated and that these shots are obtained. 19. Machine for manufacturing a non-woven veil with stabilized edges, comprising a continuous spinning station of long fiber veil, a unit for extending short fibers over the veil, a station for joining said short fibers to said veil to form the fabric, characterized in that it comprises a device for stabilizing the edge of the veil according to one or more of claims 9 to 18. 20. Non-woven fabric comprising a veil of long carded or spinning fibers with a layer of short fibers extended thereon, which are interwoven with said long fiber veil, characterized in that it has longitudinal edges (B, B ') stabilized by the method and the device according to one or more of claims 1 to 18, and for the use of a machine according to claim 19.