WO2017025271A1

WO2017025271A1 - Method for producing a structured microfilament nonwoven

Info

Publication number: WO2017025271A1
Application number: PCT/EP2016/066857
Authority: WO
Inventors: Robert Groten; Bénedicte BECK; Ulrich Jahn; Ameur Abdelkader; Jean-Francois Kerhault
Original assignee: Carl Freudenberg Kg
Priority date: 2015-08-10
Filing date: 2016-07-15
Publication date: 2017-02-16
Also published as: CN107849765A; EP3334857A1; US20180245252A1; TW201706473A; TWI633219B; DE102015010129A1

Abstract

Method for producing a structured microfilament nonwoven, in which microfilaments and/or composite filaments that are able to be split into microfilaments are spun to form at least one fibre layer, drafted and laid to form a nonwoven; the nonwoven is thermally preconsolidated; the thermally preconsolidated nonwoven is treated with a pressurized medium in order to at least partially break up the thermal preconsolidation; the nonwoven resting on a structuring surface is subjected again to a pressurized medium, whereby a structured microfilament nonwoven is obtained.

Description

Process for producing a structured microfilamentary vitrified material

description

Technical area

The present invention relates to the field of textile products and their applications.

In particular, the invention relates to a process for producing a patterned microfilamentary vitrified microfluidic nonwoven fabrics and to their use. Nonwovens are textile fabrics made of individual fibers and can be used with a wide variety of manufacturing processes, such as dry laid,

Spunbonding, Melt-blown or aerodynamic laid air laid. In melt spinning, a polymeric substance is heated in an extruder and forced through a spinneret by spinning pumps. The polymer emerges from the nozzle plate as a filament (continuous filament) in molten form, is cooled by an air flow and stretched from the melt. Of the

Air flow conveys the endless filaments onto a conveyor belt, which is designed as a sieve. Through a suction under the screen belt, the threads be fixed to form a fiber fabric. The consolidation of the

Fasergeleges can by heated rollers (calender), by a

Steam flow or by (hydro) mechanical or chemical bonding done.

The textile-physical properties of nonwovens can be controlled by the chemical and textile-physical properties of the fibers or filaments forming them. This will be the fiber or

Filament raw materials selected according to the desired chemical or physical properties, for example, with regard to their colorability, chemical resistance, their thermoformability or their

Adsorption capacity. The modulus and force-strain properties of the fibers or filaments depend on the material properties, which can be controlled by the choice of degree of crystallization and / or orientation and the cross-sectional geometry, the bending stiffness, the force absorption or the specific surface area of the individual fibers or to influence filaments.

In order to improve the appearance, the feel or the purpose of use, it is also known to provide nonwovens with a structuring.

PRIOR ART It is known to produce structured nonwovens starting from staple fibers. These fibers have a high because of their shortness

Fiber mobility and thereby form a clean structuring. A disadvantage of the use of staple fibers, however, is that the high mobility in the mechanics of a washing process leads to the dissolution of the structure. This is known in the art through the use of adhesive Binder counteracted, which adversely affects the fabric of the resulting fabrics.

DE 102008033253 A1 describes a method and a device for producing structured nonwoven fabrics, in which the nonwoven, resting on a structure-providing surface, is exposed to an under-pressurized medium. It is intended that too

structuring fleece is guided around the circumference of a drum during the application of the pressurized medium, wherein the surface of the drum has a herringbone pattern

Surface structuring has.

A disadvantage of this method is that the structuring pattern of the nonwoven fabric is not very stable and especially in mechanically demanding treatments, such as repeated washing or

Dyeing processes is affected.

DE 102008061679 A1 discloses a method for pre-consolidating a pile of fibers and / or filaments, wherein the pile is transported on a base, using a device for

Water jet needling, and wherein the means for

Wasserstrahlvernadelung is positioned at a great distance to the pad supporting the pile. Even with the nonwovens described in this document that is

Structuring pattern not very resistant to mechanical

demanding treatments.

The object of the invention is to provide structured nonwovens whose structuring patterns are also mechanical demanding treatments, such as repeated washing or

Dyeing processes is stable. At the same time, the nonwovens should be good

mechanical properties, in particular a good long-term washing resistance with satisfactory performance characteristics, a good

provide thermophysiological comfort, pleasant skin sensation and appearance.

Presentation of the invention

The invention relates to a method for producing a structured

Microfilament nonwoven fabric in which

Microfilaments and / or composite filaments which can be split into microfilaments are spun, drawn and laid down into a nonwoven fabric to form at least one fiber layer;

- The web is thermally preconsolidated;

- The thermally preconsolidated nonwoven with a pressurized

Medium is treated to at least partially break the thermal pre-consolidation;

- the web is subjected to further application to a pressurized medium, resting on a structuring surface, whereby a structured microfilament nonwoven fabric is obtained.

It has been found that with the method according to the invention

Microfilament nonwovens can be produced with a clearly defined structuring pattern, which also compared to mechanical

demanding treatments, such as repeated washing, in particular heavy duty industrial Heißwaschzyklen or dyeing operations, is stable. At the same time, the nonwoven fabrics show outstanding mechanical properties, in particular good durability for washing, with satisfaction functional properties, a good thermophysiological comfort, pleasant skin sensation and optics.

The thermal pre-consolidation represents an essential step of the process according to the invention. Through them, the fibers of the

Nonwoven fabric are transitionally stabilized so far that a trouble-free transfer to a system for acting on a pressurized medium is possible. At the same time, the bond in the nonwoven fabric is weak enough that it can be broken up again in a simple manner by the application of the pressurized medium and is therefore at least partly reversible. As a result, a limitation of the fiber mobility at the time of structuring can be avoided. This is advantageous since, in the case of irreversible preconsolidation, for example needling, the associated decrease in fiber mobility makes the structuring step more difficult and consequently no sharply structured pattern is obtainable. Furthermore, in the case of irreversible preconsolidation, the fibers are provided with a high restoring force, which additionally has a negative effect on the clarity and stability of the structuring pattern. From these

For reasons, in a preferred embodiment of the invention, the nonwoven web is not needled for preconsolidation, more preferably, it is exclusively thermally preconsolidated.

By contrast, it is possible with the method according to the invention

To obtain microfilament nonwovens with a clearly defined structuring pattern, which also surprisingly shows a high stability to mechanically demanding treatments, such as repeated washing or dyeing operations.

It is believed that the beneficial properties of having the

according to the invention prepared structured nonwoven fabrics at least partially due to the reversible thermal pre-consolidation of the web. Another positive effect of the thermal pre-consolidation is that it allows a transporting and rolling and unrolling and thus an offline process management. In addition, reversible thermal preconsolidation is also advantageous in the case of in-line process control since it makes it possible to keep the fibers stable in a desired structure in the process steps between solidification and structuring.

The thermal pre-consolidation can be carried out in the usual ways known to the person skilled in the art, for example with a heated calender. If a nonwoven comprising composite filaments is used as

Starting material used, it is advantageous in the use of a calender that already a slight splicing of the filaments can be achieved, which facilitates the subsequent splitting step and allows high yield.

The use of a hot-air blade, a through-flow dryer, for example a hot-air tunnel oven or a drum-through-air dryer through which hot air flows has also proven to be suitable It is advantageous in this method that there is no undesirable compression of the nonwoven during preconsolidation and preconsolidation in the air Meaning of a Vorverfilzens or Durchgelgelns, figuratively conceivable as "wrong

Node "can be avoided, which usually has a favorable effect on the subsequent structuring process.

The strength in which the web is thermally preconsolidated, the expert can adjust depending on the materials used, the basis weights and the desired degree of solidification. For higher basis weights of, for example, more than 130 g / m ² , it may be advantageous Pre-solidification by means of Durchströmbeheizung perform to ensure a Durchhizen of the web, for example, in the calender.

Following thermal pre-consolidation of the web, it is treated with a pressurized medium. For this purpose, the nonwoven can be easily transferred to a system for pressurization with a pressurized medium. This is possible because the fleece, as explained above, can be given sufficient stability by the thermal pre-consolidation.

This treatment serves to at least partially break up the thermal pre-consolidation. This can be a limitation of

Fiber mobility at the time of structuring are avoided. This is advantageous as explained above, since in this way the fleece can be provided with a sharply structured pattern in the subsequent structuring step.

The extent of breakage can be known in the art, for example by adjusting the pressure and the

Treatment duration to be controlled. In principle, it has proved to be advantageous if the treatment of the nonwoven fabric is carried out in such a way that during structuring the thermal preconsolidation is completely or almost completely broken. Practical tests have shown that the more complete the breaking of the preconsolidation, the sharper the pattern becomes. Nevertheless, it may be appropriate to the

Vorverfestigung only partially break, for example, to obtain a more consolidated nonwoven fabric.

As a pressurized medium, a variety of media can be used. Particularly simple and inexpensive is the use of water. For the application of water, customary equipment for hydroentanglement can be used.

The adjustment of the apply pressure may vary depending on the materials used and the desired extent of thermal pre-consolidation breakup. As a rule, pressures in the range of 200-300 bar have proven to be favorable.

By the application of the pressurized medium, depending on the selected starting materials and the set process conditions in addition various other processes such

Compaction, fiber separation, splitting and / or entanglement of the fibers take place. Conveniently, the fleece during the

Applying to the pressurized medium around the circumference of a drum, in particular a calender guided. In this case, the nonwoven can rest on a structure-giving surface or on a non-structuring surface.

In order to structure the nonwoven, this invention is subjected to a further application to a pressurized medium, resting on a structuring surface, whereby a structured layer is formed

Microfilament nonwoven fabric is obtained. The structuring pattern can be formed two-dimensionally. However, it is particularly effective if the pattern is formed in three dimensions.

Advantageously, both treatments according to the invention can be carried out with a medium under pressure in the same device, for example in a conventional device for water-jet needling. As a structuring surface, the support surface of a support member can act and have for this purpose elevations. The raises are designed so that they represent the negative of the desired pattern.

Advantageously, the carrier surface additionally has perforations as drainage openings. By subjecting the web to a pressurized medium, at least a portion of the fibers of the web placed on the ridges upon application of the liquid may be flushed down the ridges by the liquid, thereby creating the desired pattern in the web.

In a preferred embodiment of the invention, the carrier element is designed as a preferably perforated drum. In this embodiment, the fleece to be structured is expediently guided on a structuring belt and in particular around the circumference of the drum during the application of the medium under pressure. As a result, a particularly simple and efficient process control is possible.

In addition to patterning the web, other operations such as further breaking of the thermal pre-consolidation, fiber separation, compaction, entanglement and / or entanglement of the fibers may take place. If the fleece contains composite filaments, their splitting takes place

expediently in the context of this procedural step.

With the method according to the invention, by varying the shape of the elevations on the carrier surface, it is possible to produce nonwoven fabrics having a wide variety of patterns. Thus, the elevations, for example, punctiform, circular, line-shaped, linear, wavy, diamond-shaped. Also conceivable is the figurative design of the pattern, whereby the nonwoven fabric can be equipped with pictures, comparable to the watermark known in paper. Should perforations in the nonwoven fabric may be formed, the support surface may have elevations with a polygonal, circular, semicircular or oval cross-sectional shape.

The type of patterning pattern introduced can be chosen depending on the desired optics. For example, the nonwoven fabric may be provided with a wave pattern, herringbone pattern, burl pattern, or textile patterns such as burlap, twill, satin, doubled, and / or jacquard patterns. It is also conceivable to provide the nonwoven fabric with perforations.

As a pressurized medium, the most varied media and preferably water can also be used in this process step.

The setting of the apply pressure may vary depending on the materials used and the desired patterning results. As a rule, pressures in the range have been favorable

proven from 200-300 bar.

As mentioned above, the support surface for removal of the

Application of medium used advantageously perforations as drainage openings. Alternatively and / or additionally, however, the medium can also be removed in a separate process step.

When subjected to a pressurized medium, be it in the context of breaking the thermal pre-consolidation or in the structuring, the microfilaments, as known in the art, be entangled and solidified.

Microfilaments are characterized by a very low average titer of less than 1 dtex. An advantage of using microfilaments is that due to the low bending stiffness of the filaments particularly clearly defined patterning patterns can be achieved, and that the

Further processing of structured nonwoven fabric is particularly easy. In a preferred embodiment of the invention, the microfilaments have a titer between 0.1 dtex and 0.5 dtex and in particular from 0.15 to 0.3 dtex. It has been found that in these titers ranges a good

Stability of the structuring (sliding strength of the filaments) can be achieved and the structuring does not tend to collapse. The use of even finer titers, for example from 0.05 dtex to 0.3 dtex can lead to even better stability of structuring, but also increases the tendency of the three-dimensional structures to collapse due to the ever-decreasing flexural rigidity of the microfilaments. The term filaments according to the invention are understood to mean fibers which, unlike staple fibers, have a theoretically unlimited length. The advantage of using filaments over staple fibers is the mechanical strength of the nonwoven fabric made therefrom. As the length of the fiber increases, the number of friction (or bonding) points with other fibers increases. Short fibers therefore have fewer points of friction, when the textile is loaded the fibers can easily shift and are easily pulled out of the textile.

With increasing fiber length increases with the number of friction (or

Binding) points also the slip resistance and the force necessary to pull the fiber out of the composite. With a very large fiber length, this does not succeed at all, so that destruction of the textile can take place only by tearing the fiber. The materials making up the microfilaments and / or composite filaments may be selected depending on the desired properties of the structured nonwoven fabric made therefrom. It is essential for the method according to the invention that the filaments are at least partially thermally solidifiable. This is advantageous because so on one

Vorverflechtung or needling or chemical bonding of the fibers can be dispensed with.

As suitable for a variety of applications have become

Microfilaments and / or composite filaments have been found which contain thermoplastic polymers such as polyolefins, in particular polyethylene and / or of thermoplastic polymers, in particular the aforementioned

consist of thermoplastic polymers. In order to carry out the thermal pre-consolidation industrially safe, it is advantageous if the microfilaments and / or composite filaments have at least two different polymers whose melting points differ by at least 10 ° C, for example from 10 ° C to 30 ° C, more preferably in at least 15 °, for example from 15 ° C to 25 ° C and in particular by at least 20 °, for example from 20 ° C to 25 ° C such as PET (256 ° C) and PA6 (225 ° C). It is advantageous for the method described above if the polymers used are incompatible, immiscible and thus not glued together. In order to achieve a sufficient degree of thermal preconsolidation, it is furthermore advantageous if the proportion of thermoplastic polymers in the nonwoven fabric is at least 20% by weight, preferably from 25% by weight to 100%

% By weight, more preferably from 40% by weight to 100% by weight, even more preferably from 50% by weight to 100% by weight, even more preferably from 60% by weight to 100% by weight, more preferably from 70% by weight. to 100% by weight, more preferably from 80% by weight to 100% by weight and in particular from 90% by weight to 100% by weight.

In order to achieve a sufficient influence of the microfilaments, it is advantageous if microfilaments and / or composite filaments are used in such a type and amount and optionally the split degree is adjusted so that the proportion of microfilaments, based on the total weight of the nonwoven fabric at least 70 wt %, preferably from 70% by weight to 100% by weight, and especially about 100% by weight.

In principle, it is conceivable that the nonwoven fabric also has other fibers that are not microfilaments. In this case, however, is advantageous not to set the proportion of other fibers too high as with increasing

Fiber titer reduces the conformability of the fiber to the structuring surface. Against this background, the proportion of further fibers having a titre of more than 1 dtex, if present, according to the invention is preferably at most 25% by weight, more preferably at most 10% by weight and

In particular, no further fibers are present. According to the invention, the nonwoven fabric is preferably produced starting from composite filaments which can be split into microfilaments. In particular, the proportion of the composite filaments in the nonwoven fabric is preferably set to more than 70% by weight, more preferably more than 80% by weight, more preferably more than 90% and even more preferably more than 95% by weight. Composite filaments consist of at least two elementary filaments and can be split into microfilaments and solidified by exposure to a pressurized medium, for example water jet needling, as is known to those skilled in the art. The microfilaments obtained by splitting have a titre of less than 1 dtex, preferably between 0.1 dtex and 0.5 dtex and

in particular from 0.15 to 0.3 dtex. It has been found that in these titanium regions a good stability of the structuring (sliding strength of the filaments) can be achieved and the structuring does not tend to collapse. As described above, it is also possible to use even finer titers, for example from 0.05 dtex to 0.3 dtex.

An advantage of the use of composite filaments as starting material for the production of the microfilaments is that the titer of the microfilaments produced from them can be adjusted in a simple manner by varying the number of microfilaments contained in the composite filaments.

Here, the titer of the composite filaments can remain constant, which

Process technology is advantageous.

Another advantage of the use of the composite filaments is that the nonwoven fabric production without the use of solvents, chemical

Binders and can be performed with a minimum of process steps. Since it is also possible to dispense with the use of solvents during structuring, it is therefore possible to advantageously carry out the method according to the invention in a very environmentally friendly and cost-effective manner. Thus, it is possible to comply with the nonwovens according to the invention the requirements of Oeko-Tex Standard 100, product class 1. Another advantage of the use of the composite filaments is that they are easily applied by pressurization

standing medium, as part of the disruption of the thermal

Pre-consolidation and / or structuring can be split and solidified. The degree of chipping advantageously amounts to more than 70% by weight, more preferably more than 80% by weight, more preferably more than 90% and even more preferably more than 95% by weight.

In one embodiment of the invention, the nonwoven is rolled up after the thermal preconsolidation, optionally temporarily stored, and provided for further processing (off-line process control). However, it is likewise conceivable to carry out the treatment with the pressurized medium directly after the thermal preconsolidation (on-line process control).

The microfilaments and the composite filaments used as starting material for the production of the microfilaments can be prepared by methods known to those skilled in the art. Suitable processes are in particular melt spinning (spunbonding).

To produce the microfilaments and / or the composite filaments, polymeric substances can be heated under pressure, for example in extruders, and pressed through bi- or multicomponent nozzles, wherein

Endless filaments are formed. After exiting the extrusion die, the continuous filaments may be drawn and positioned by means of dynamic laydown on a conveyor belt deflected transversely to form a chamferage. Advantageous on a deflected in the transverse direction

Positioning of the continuous filaments means that this increases the isotropy of the mechanical properties of the nonwoven fabric.

The composite filaments can have a wide variety of cross-sections known for the production of split fibers, for example a cross-section with orange-like or "pie"-named microstructure structures, wherein the segments can contain different, alternately incompatible polymers. In this case, the pie arrangement of the fibers may have, for example, 2, 4, 8, 16, 24, 32 segments or 64 segments, so that the composite filaments accordingly consist of 2, 4, 8, 16, 24, 32 or 64 microfilaments.

Also suitable are hollow-pie structures that can also have an asymmetrically axially extending cavity. Pie structures, in particular hollow-pie structures, can be split particularly easily.

The microfilaments may be formed in cross-section n-sided, or multilobal.

In a preferred embodiment of the invention, the

Composite filaments have different filaments containing at least two, preferably incompatible, thermoplastic polymers. This allows a particularly simple splitting achieved and at the same time

Mehrkomponentenvliesstoff be obtained.

Incompatible polymers are to be understood as meaning those polymers which in combination do not give only limited or poorly adhering pairings. Such a composite filament has a good cleavability in microfilaments and causes a favorable ratio of strength to basis weight. Another advantage of the use of incompatible polymers is that the bond achieved in the thermal pre-consolidation can be broken up more easily in the subsequent treatment with a pressurized medium, and due to the increased thereby achieved

Fiber mobility leads to improved structurability of the nonwoven fabric.

Also in the inventive embodiment of the invention, in which already contains the fleece microfilaments, it is advantageous if the Microfilaments comprise at least two types of microfilaments consisting of different incompatible polymers.

The composite filaments preferably contain at least one incompatible polymer pair. As incompatible polymer pairs, are preferably

Polyolefins, polyesters, polyamides and / or polyurethanes used in such a combination that not, only conditionally or difficultly adhesive pairings arise. Only conditionally or poorly adhering pairings are present if the splitting of the composite filaments having these pairings is simpler than with a composite filament which consists only of one of the polymers used.

The polymer pairs used are particularly preferably selected from polymer pairs with at least one polyolefin and / or at least one polyamide, preferably with polyethylene, such as polypropylene / polyethylene,

Polyamides / polyethylene or polyethylene terephthalate / polyethylene, or with polypropylene, such as polypropylene / polyethylene, polyamide 6 / polypropylene or polyethylene terephthalate / polypropylene. Very particular preference is given to polymer pairs with at least one polyester and / or at least one polyamide.

Polymer pairs with at least one polyamide or with at least one

Polyethylene terephthalate are preferred because of their conditional adhesiveness, and polymer pairs with at least one polyolefin are particularly preferred because of their poor tackiness.

Particularly preferred components are polyesters, preferably polyethylene terephthalate, polylactic acid and / or polybutylene terephthalate on the one hand, polyamide, preferably polyamide 6, polyamide 66, polyamide 46, on the other hand, if appropriate, in combination with one or more further polymers incompatible with the abovementioned components, preferably selected from polyolefins, have proven particularly expedient. This combination has excellent cleavability. The combination of polyethylene terephthalate and polyamide 6 or of polyethylene terephthalate and polyamide 66 is very particularly preferred.

For producing the microfilaments and / or composite filaments

The polymers used may contain at least one additive selected from the group consisting of color pigments, antistatic agents, antimicrobials such as copper, silver, gold, or hydrophilizing or hydrophobing additives in an amount of from 150 ppm to 10% by weight. The use of

mentioned additives in the polymers used allows customization to customer requirements.

Conceivable is the antistatic finish of the surface, as well as its inspiration with care substances. Also conceivable is the subsequent finishing of the nonwoven fabric with hydrophilic, hydrophobic or antistatic

Spin finishes, as well as their realization with care substances. It is also conceivable additives for surface modification already in the

To enter continuous film production in an extruder. Even in the case of a mass-dyeing, no subsequent dyeing is necessary since pigments can already be introduced into an extruder during continuous-film production. Further, the nonwoven fabric may be subjected to a chemical-type bonding or finishing such as an anti-pilling treatment, a hydrophilization, an antistatic treatment, a refractory improving treatment and / or a change in tactile properties or gloss, a treatment mechanical type or a treatment in the tumbler and / or a treatment for

Change in appearance, such as dyeing or printing.

The invention further relates to a structured nonwoven fabric which can be produced by the method according to the invention. As explained above, the nonwoven fabric is characterized in particular by being

Structuring pattern is very clearly contoured and is also resistant to mechanically demanding treatments, such as repeated washing or dyeing operations. It has thus been found that exemplary nonwovens according to the invention can also be used after 30

Household washing cycles at 90 ° C according to DIN EN ISO 6330 still have visually and / or haptic recognizable patterning pattern.

In addition, the nonwoven fabric shows good due to the microfilaments

mechanical properties, even at low basis weights, a

Survive the structuring of a mechanically demanding

Dyeing process (jet-dye) a good long-term washing resistance with satisfactory performance characteristics, a good thermophysiological comfort, a high fineness, density, excellent cleaning performance, a high lightness, sound-absorbing properties and a pleasant skin sensor and optics.

Compared to nonwovens, in which no preconsolidation is carried out, the nonwoven fabric according to the invention is characterized in that the

Structures are very clearly marked. So is in perforations than

For example, patterning patterns reveal that these perforations are substantially free of hole-hiding or hole-bridging fibers. Surprisingly, this effect can also be observed if the thermal pre-consolidation was completely broken before embossing. In According to a preferred embodiment of the invention, the nonwoven fabric according to the invention is not needled and / or solidified by binders.

In contrast to subsequently thermally introduced structurings, the nonwoven fabric can also be provided with a structuring pattern which is not hardened with respect to the rest of the nonwoven fabric. The fibers are not destroyed by this structuring process but the intact filaments are pushed only to the edge of the hole structures and there matted together, comparable to a reinforcement of buttonholes. As a result, they can continue to contribute fully to the mechanical strength of the textile. The nonwoven fabric can have a wide variety of structuring, for example wave patterns, herringbone patterns,

Nap patterns or textile patterns such as canvas, twill, atlas,

Have double fabric and / or Jacquard patterns and / or perforations.

According to the invention, the nonwoven fabric is at least partially in

Microfilaments having an average titre of less than 1 dtex, preferably between 0.1 dtex and 0.5 dtex and in particular of 0.15-0.3 dtex, split and intertwined composite filaments. The proportion of split microfilaments, based on the total weight of the

Nonwoven fabric preferably at least 70% by weight, preferably from 70% by weight to 100% by weight, and especially about 100% by weight.

As explained above, the nonwoven fabric preferably comprises microfilaments and / or at least partially split composite filaments containing thermoplastic polymers, such as polyolefins, in particular polyethylene, and / or thermoplastic polymers, in particular the abovementioned ones

consist of thermoplastic polymers. The microfilaments and / or at least partially split composite filaments advantageously contain, as described above, various, alternately incompatible polymers. Preferably, the microfilaments and / or composite filaments comprise at least two incompatible polymers, as above

described.

It is likewise advantageous if the proportion of thermoplastic polymers in the nonwoven fabric is at least 20% by weight, preferably from 25% by weight to 100%

% By weight, more preferably from 40% by weight to 100% by weight, even more preferably from 50% by weight to 100% by weight, even more preferably from 60% by weight to 100% by weight, more preferably from 70% by weight. to 100% by weight, more preferably from 80% by weight to 100% by weight and in particular from 90% by weight to 100% by weight. In a preferred embodiment of the invention that is

Basis weight of the nonwoven fabric is less than 50 g / m ² , for example 20 to 50 g / m ² , more preferably 20 to 40 g / m ² and in particular 25 to 35 g / m ² .

According to the invention, the basis weight is measured according to DIN EN 29073. In this super-light category, the pattern of structuring can have a particularly positive effect on the uniformity of the distribution of the microfilaments and facilitate the processing. This makes it possible to produce three-dimensionally structured nonwovens that are significantly lighter than

lightweight cloths of comparable performance properties from other manufacturing processes. Thanks to the fineness and density of the microfilaments, these nonwovens, in spite of their small basis weight, provide excellent cleaning performance if desired.

In a further preferred embodiment of the invention, the basis weight of the nonwoven fabric is more than 50 g / m ² , for example 50 to 130 g / m ² , more preferably 70 to 120 g / m ² , even more preferably 80 to 110 g / m ² . Nonwovens can be produced in this medium-weight category, in which the three-dimensional structure can adjust the feel and appearance of fabrics. As a result, for example, towels can be produced which are both dense, light and effective and also offer the familiar with consumers textile look.

Another object of the present invention is the use of microfilament nonwoven fabric according to the invention as a cleaning cloth, towel, Sanitärtuch, bedding, upholstery, lining material.

The invention is explained in more detail below by means of an example:

example

By means of 2 extruders, 70% PET and 30% PA6 are melted and combined in a spinneret for bicomponent filaments, extruded together in the form of endless PIE16 filaments and drawn at about 3500 m / min to a titer in the unsplit state of about 2.4 dtex and to a

Filing tape laid to a pile of 37 g / m ² . The pile is stabilized by applying a stream of air, possibly also heated, from above through the pile through a deposit belt, which in turn is sucked off from below. With a free sag of only a few centimeters, the pile is guided into a calender, which is guided with a line pressure of 33 daN / cm and a temperature of both rolls of 150 ° C. The thermally pre-bonded nonwoven is rolled up, is so manageable (roll up and down) and is fed to another location of a hydroentanglement plant.

In the hydroentanglement, which is performed with four drums, the steps overlap fracturing of the preconsolidation, tracking the Bi-component filaments in polyamide and polyester segments, nestling the filaments on the extracted water drum structures and entangling the filaments in the turbulent flows between water jet and water

Underlay (sieve drum).

In the test arrangement, fine mesh structures, ie as smooth as possible screening drums for the first three passages, proved to be advantageous, while the fourth screening drum was the structuring one. The first 3 passages are driven moderately with alternating impingement of the sides (ABA): The structuring screen drum is subjected to at least two passages on the same side (BB) and high pressures. It is then dried by a through-suction and wound at low tension (winding pressure) into a roll. In this second stage of the manufacturing process, the goods, depending on the structure in width 7 -15% and also the basis weight increases by 7 - 10%. In the specific case of 37 g / m ² after the thermal preconsolidation in step 1 to 40g / m ² after hydroentanglement and drying. The product can thus be subjected to disperse dyeing in the jet and maintains its structuring.

FIG. 1 shows a perforated microfilamentary material produced by the process according to the invention. It can be clearly seen that the introduced perforation has a very clearly defined edge and is only crossed by very few fibers.

Claims

claims

A process for producing a structured microfilament nonwoven fabric in which

Microfilaments and / or splittable in microfilaments

Spun composite filaments to at least one fiber layer, stretched and stored to form a nonwoven;

the web is thermally preconsolidated;

the thermally precured web is treated with a pressurized medium to remove the thermal

Pre-consolidation at least partially break up; the nonwoven resting on a structuring surface further pressurized

Medium is exposed, creating a more structured

Microfilament nonwoven fabric is obtained.

2. The method according to claim 1, characterized in that the nonwoven is not needled or glued for preconsolidation.

3. The method according to claim 1 or 2, characterized in that the thermal pre-consolidation is carried out with a heated calender.

4. The method according to one or more of the preceding claims, characterized in that the treatment with a pressurized medium for breaking the thermal pre-solidification on the one hand and the treatment with a pressurized medium for structuring the nonwoven on the other hand done in the same device.

5. The method according to one or more of the preceding claims, characterized in that by the treatments with a pressurized medium for breaking the thermal pre-consolidation and / or structuring of the web

Composite filaments are at least partially split into microfilaments and intertwined with each other.

6. Structured microfilament nonwoven fabric, producible by a process according to one or more of the preceding claims.

7. Structured microfilament nonwoven fabric according to claim 6, characterized

in that the structuring pattern can be recognized visually and / or haptically even after 30 household washes at 90 ° C. in accordance with DIN EN ISO 6330.

8. microfilament nonwoven fabric according to claim 6 or 7, characterized

characterized in that the basis weight of the nonwoven fabric is less than 50 g / m ² .

9. microfilament nonwoven fabric according to one or more of claims 6 to 8, characterized in that the microfilaments contain thermoplastic polymers in a proportion of at least 20 wt.%, Based on the total weight of the nonwoven fabric.

10. microfilament nonwoven fabric according to one or more of claims 6 to 8, characterized in that the proportion of microfilaments, based on the total weight of the nonwoven fabric at least 70 wt.%, preferably from 70% by weight to 100% by weight, and especially about 100% by weight.

11. microfilament nonwoven fabric according to one or more of claims 6 to 8, characterized in that the proportion of at least partially split into microfilaments and entangled with each other

Composite filaments in Mikrofilamentvliesstoff more than 70 wt.% Is.

12. microfilament nonwoven fabric according to one or more of claims 6 to

11, characterized in that the degree of splitting of the composite filaments is more than 80%, preferably more than 95%.

13. microfilament nonwoven fabric according to one or more of claims 6 to

12, characterized in that the composite filaments and / or the microfilaments at least two incompatible, thermoplastic

Polymers selected from polyester, preferably

Polyethylene terephthalate, polylactic acid and / or

Polybutylene terephthalate on the one hand, polyamide, preferably polyamide 6, polyamide 66, polyamide 46, on the other hand.

14. microfilament nonwoven fabric according to one or more of claims 6 to

13, characterized in that the composite filaments at least one polymer pair of at least one polyester, preferably

Polyethylene terephthalate on the one hand and at least one polyamide, preferably polyamide 6 and / or polyamide 66 on the other hand.

15. Use of a microfilament nonwoven fabric according to one or more of claims 6 to 14 as a cleaning cloth, towel, Sanitärtuch, bedding, upholstery and / or lining material.