DE102022115205A1 - Method and device for producing a nonwoven fabric - Google Patents

Abstract

The invention relates to a method for producing a nonwoven fabric with at least one nonwoven web made of fibers. The fibers are produced with at least one fiber production device. The fibers are then deposited on at least one storage device to form the nonwoven web. The nonwoven web or the nonwoven fabric is solidified with at least one calender roll and the nonwoven fabric is also solidified or main solidified with at least one hot fluid main solidifying device.

Description

The invention relates to a method for producing a nonwoven fabric with at least one nonwoven web of fibers, wherein fibers are produced with at least one fiber production device, in particular with at least one spinning beam, the fibers then being deposited on at least one storage device, in particular on a storage screen belt, to form the nonwoven web . The invention also relates to a device for producing a nonwoven fabric.

Methods and devices for producing nonwovens are basically known from practice in various embodiments. The fibers produced are usually placed on a storage device to form the nonwoven web and then pre-solidified in order to ensure the transportability of the nonwoven web or nonwoven fabric and to ensure that the nonwoven web is not displaced or destroyed during transport through the device. For further solidification or main solidification, the nonwoven material is usually fed to a subsequent device. Calenders with at least one calender roll, in particular with at least one pair of calender rolls, are known as subsequent devices for the consolidation or main consolidation of nonwovens. Calender rolls with embossing elements are often used, which, during solidification, introduce an embossed pattern consisting of a large number of embossings into the nonwoven fabric. Nonwovens that have been treated with at least one calender are characterized by advantageous mechanical strength, but these nonwovens often have a small thickness or a small volume. In addition, the embossed patterns introduced into the nonwovens using a calender are advantageous or necessary with regard to the mechanical properties of the nonwovens, but are disadvantageous for aesthetic reasons, since the optical properties of the nonwovens are thereby adversely affected. In practice, hot fluid consolidation devices or hot air consolidation devices such as hot air ovens are also known as an alternative to the consolidation or main consolidation of nonwovens. Nonwovens that are consolidated or main-solidified with such consolidation devices are generally characterized by an advantageous thickness or voluminousness, but often have an undesirable stiffness or are difficult to drape and sometimes have a disadvantageously low abrasion resistance.

An acceptable compromise between sufficient mechanical strength, satisfactory thickness or voluminousness, low stiffness or satisfactory drapability and sufficient abrasion resistance has so far only been possible by mixing different types of fibers in nonwovens. However, this is complex and the corresponding procedures are not very flexible in their use.

In contrast, the invention is based on the technical problem of specifying a method of the type mentioned at the outset, in which the disadvantages described above can be avoided effectively and reliably and with which, in particular, a nonwoven fabric can be produced which has advantageous mechanical properties, for example sufficient mechanical strength or surface resistance, by sufficient thickness or voluminousness, by low stiffness or satisfactory drapability and preferably by improved abrasion resistance, with an optimal compromise between these nonwoven material properties being particularly desirable. In addition, the invention is based on the technical problem of specifying a corresponding device for producing a nonwoven fabric and such a nonwoven fabric.

To solve the technical problem, the invention teaches a method for producing a nonwoven fabric with at least one nonwoven web made of fibers, with fibers being produced with at least one fiber production device, in particular with at least one spinning beam, the fibers then being placed on at least one storage device, in particular on a storage screen belt , are laid down to form the nonwoven web, wherein the nonwoven web or the nonwoven fabric is solidified with at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll, and wherein the nonwoven fabric is also solidified with at least one hot fluid main solidification device, in particular with at least one hot air Main solidification device, solidified or main solidified.

The fact that the nonwoven fabric has at least one nonwoven web made of fibers means in the context of the invention in particular that the nonwoven fabric has at least one nonwoven web or nonwoven layer made of produced and deposited fibers. According to one embodiment, the nonwoven fabric can have only one nonwoven web or one nonwoven layer or it can also have several nonwoven webs or nonwoven layers arranged one above the other, which are combined to form the nonwoven laminate.

In the context of the invention, the term solidification or main solidification means in particular a solidification of the nonwoven material, which leads to a higher degree of solidification of the nonwoven material leads as a pre-consolidation. It is within the scope of the invention that a lower or a higher degree of consolidation of the nonwoven is achieved with a main consolidation than with a consolidation or that with a main consolidation a degree of consolidation of the nonwoven that is identical or essentially identical to a consolidation is achieved.

According to a preferred embodiment of the invention, the nonwoven fabric is produced as a spunbond nonwoven fabric with at least one spunbond nonwoven web or with at least one spunbond nonwoven fabric layer. It is possible for the nonwoven fabric to be produced as a nonwoven laminate from at least two spunbond nonwoven webs or at least two spunbond nonwoven layers. However, it is also possible for the nonwoven fabric or the nonwoven laminate to have at least one meltblown nonwoven web or meltblown nonwoven layer. It is also within the scope of the method according to the invention that the nonwoven fabric is produced as a nonwoven laminate from at least three, for example at least four nonwoven webs or nonwoven layers. The individual nonwoven webs or nonwoven fabric layers can each be laid down as spunbond nonwoven webs or nonwoven fabric layers. In principle, the nonwoven laminate could also be produced with at least one meltblown nonwoven web or meltblown nonwoven layer. The spunbond nonwoven webs or the spunbond nonwoven layers are preferably each made from continuous filaments or crimped continuous filaments. This is explained in more detail below.

In the context of the invention, the term hot fluid means a tempered or heated fluid. The hot fluid is preferably a tempered or heated gas and particularly preferably hot air. In principle, the hot fluid can also be a tempered or heated liquid, for example water.

A particularly preferred embodiment of the method according to the invention is characterized in that the nonwoven material is detached from the storage device before solidification with the at least one calender roll and/or before solidification or main solidification with the at least one hot fluid main solidification device. Particularly preferably, both the solidification takes place with the at least one calender roll or with the at least one calender having the calender roll, as well as the solidification or main solidification with the at least one hot fluid main solidification device after the nonwoven has been detached from the depositing device. For this purpose, the nonwoven material is expediently transferred to the calender roll or the calender or to the hot fluid main consolidation device after it has been detached from the depositing device. In principle, it is also possible within the scope of the invention for the solidification or main solidification to take place with the at least one hot air main solidification device on or above the depositing sieve belt and for the nonwoven material to preferably only be detached from the depositing device afterwards.

It has proven particularly useful in the context of the method according to the invention that the solidification of the nonwoven fabric with the at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll, before or after the solidification or main solidification of the nonwoven fabric with the at least one hot fluid Main solidification device, in particular with the at least one hot air main solidification device, takes place. Very particularly preferably, the nonwoven material, in particular after being detached from the storage device, is first solidified with the at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll, and then with the at least one hot fluid main solidification device, in particular with the at least one Hot air main solidification device solidified or main solidified. This sequence of solidification steps has proven particularly useful in the context of the invention and in solving the technical problem.

It is recommended that after depositing on the depositing device and before solidification or main solidification, the nonwoven fabric is initially preferably with at least one, preferably the at least one fiber producing device or the at least one spinning beam, downstream, in particular immediately downstream, pre-solidification device, preferably with at least one hot fluid pre-solidification device pre-solidified with at least one hot air pre-solidification device. The pre-solidification thus takes place in particular before solidification with the at least one calender roll or with the at least one calender and before solidification or main solidification with the at least one hot fluid main solidification device. The pre-solidification step ensures in particular the transportability of the deposited nonwoven web or nonwoven fabric and, according to a preferred embodiment, also the detachability of the nonwoven fabric from the storage device, as well as the functionally reliable transfer to one of the devices provided according to the invention for solidifying the nonwoven fabric. If, according to a preferred embodiment of the method according to the invention, a nonwoven fabric with at least two nonwoven webs of fibers is produced, it is preferred that after depositing each Nonwoven web is pre-consolidated with a pre-consolidation device or hot fluid pre-consolidation device, which is expediently connected downstream of the assigned fiber production device or the assigned spinning beam, in particular immediately downstream.

It is within the scope of the method according to the invention that the at least one hot fluid pre-solidification device or hot air pre-solidification device is designed as a hot air knife and/or as a hot air field. In principle, the pre-consolidation device can also be at least one roller or a smooth roller, in particular a pair of rollers or a pair of smooth rollers. If the nonwoven fabric is produced according to one embodiment with only one nonwoven web, it is preferred that a hot air knife is used as the pre-consolidation device. If the nonwoven fabric is produced according to the preferred embodiment with several nonwoven webs or nonwoven fabric layers, a hot air knife is preferably used as a pre-consolidation device for the topmost or last laid nonwoven fabric web or nonwoven fabric layer, and in particular a hot air knife and a hot air field are used as a preconsolidation device for the remaining nonwoven webs or nonwoven fabric layers used. In the latter case, residence times of over 0.1 s for hot air exposure have proven particularly useful.

It has proven particularly useful within the scope of the invention that the at least one hot fluid main solidification device or the at least one hot air main solidification device is designed as a hot air oven, particularly preferably as an Omega oven and/or as a multi-drum oven and/or as a single belt oven and/or is designed as a double belt furnace. The consolidation or main consolidation expediently takes place with the at least one hot fluid main consolidation device by applying the nonwoven fabric to one or both sides with at least one hot fluid in the at least one hot fluid main consolidation device.

It has also proven particularly useful within the scope of the invention that the at least one hot fluid main solidification device or the at least one hot air main solidification device is designed as a hot air oven, particularly preferably as a hot air field and/or as a multi-drum oven and/or as a single belt oven and/or as Double belt furnace is designed. According to one embodiment of the invention, the solidification or main solidification takes place with the at least one hot fluid main solidification device by applying one or both sides of the nonwoven fabric to at least one hot fluid in the at least one hot fluid main solidification device and in particular before detachment from the storage device, the nonwoven fabric preferably subsequently is solidified after detachment with the at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll. It is also within the scope of the invention that at least two hot fluid main solidification devices are provided, in which case a first solidification or main solidification of the nonwoven fabric is then preferably carried out with a first hot fluid main solidification device before the nonwoven fabric is detached from the depositing device and in which case a second or further solidification or main solidification with a second hot fluid main solidification device after the detachment of the nonwoven from the storage device and particularly preferably after solidification with the at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll. In this exemplary embodiment, the at least one calender roll is thus preferably arranged in the conveying direction F of the nonwoven material between two hot fluid main consolidation devices.

According to a particularly preferred embodiment of the method according to the invention, the residence time of the nonwoven in the hot fluid main bonding device is 0.4 s to 25 s, preferably 1 s to 15 s and/or the fluid velocity of the fluid of the hot fluid main bonding device is 0.4 to 3 m/ s, preferably 0.5 to 2 m/s.

It is within the scope of the invention that the surface temperature T1 of the at least one calender roll, in particular of the at least one calender or pair of calender rolls, is higher, preferably by 0.5 ° C to 10 ° C, preferably by 1 ° C to 5 ° C is higher than the fluid temperature T2 of the at least one hot fluid main solidification device or is lower than the fluid temperature T2 of the at least one hot fluid main solidification device or is identical or substantially identical to the fluid temperature T2 of the at least one hot fluid main solidification device. In the context of the invention, the at least one calender roll, in particular the at least one calender or pair of calender rolls having the calender roll, is preferably a heated calender roll or a heated calender. The temperature conditions of the surface temperature of the at least one calender roll or the calender and the fluid temperature of the at least one hot fluid main solidification device can - in particular in combination with the residence times and / or fluid velocities explained above - a method ren are provided, with which nonwovens can be produced very flexibly, which are characterized by an optimal compromise of their properties, so that the technical problem explained above can be solved very flexibly, easily and functionally.

It is fundamentally within the scope of the invention that the fibers of the at least one nonwoven web are produced as short fibers or that the at least one nonwoven web contains short fibers. According to a preferred embodiment, the fibers of the at least one nonwoven web are produced as endless filaments. Particularly preferably, the fibers of all nonwoven webs are produced as continuous filaments in the process according to the invention. Then, within the scope of the invention, fibers mean in particular endless filaments. Due to their virtually endless length, endless filaments differ from short fibers, which have significantly shorter lengths of, for example, 1 mm to 60 mm.

A particularly preferred embodiment of the method according to the invention is characterized in that the fibers of the at least one nonwoven web are produced or spun as continuous filaments. Preferably, the fibers of the at least one nonwoven web or at least one nonwoven web of the nonwoven fabric are produced as continuous filaments made of at least one thermoplastic, preferably of at least one polyolefin. The at least one polyolefin is recommended to be polypropylene and/or polyethylene. In principle, the continuous filaments can also be produced from other thermoplastics such as polyesters, for example polyethylene terephthalate (PET) and/or polylactide (PLA), as well as from mixtures of the thermoplastics mentioned above. According to one embodiment, copolymers of the thermoplastics mentioned are used. Common additives such as plasticizers, fillers, colors and the like can be added to the thermoplastics mentioned. It is within the scope of the invention that the continuous filaments of the at least one nonwoven web or at least one nonwoven web of the nonwoven fabric are produced as spunbond continuous filaments. In principle, it is also possible for the continuous filaments of the at least one nonwoven web or one nonwoven web of the nonwoven fabric to be produced as meltblown continuous filaments.

According to a particularly preferred embodiment of the method according to the invention, the fibers of the at least one nonwoven web are produced or spun as crimped continuous filaments, the continuous filaments or the crimped continuous filaments being particularly preferably produced or spun as multicomponent filaments and very particularly preferably as bicomponent filaments.

It has proven particularly useful in this context that the multicomponent filaments or bicomponent filaments have a first, preferably low-melting, component which consists or essentially consists of at least one thermoplastic, in particular at least one polyolefin, preferably polyethylene and/or polypropylene and/or that the multicomponent filaments or bicomponent filaments have a second or further, preferably higher melting, component which consists or essentially consists of at least one thermoplastic, in particular of at least one polyester and/or polypropylene. In the context of the invention, the term low-melting component, in particular first low-melting component, means in particular a component of the multicomponent filaments or bicomponent filaments which has a lower melting temperature than a higher-melting component in comparison, in particular the second or further higher-melting component of the multicomponent filaments or bicomponent filaments. In the context of the invention, the low-melting component or the first low-melting component of the multicomponent filaments or bicomponent filaments is in particular a binding component for the multicomponent filaments or bicomponent filaments.

Polyethylene terephthalate (PET) and/or polylactide (PLA) are particularly suitable as polyester in the context of the invention. According to one embodiment, copolymers of these plastics are used. If “essentially consists” is stated here or below in relation to the components of the multi-component filaments or the bi-component filaments and in particular to a plastic or a polymer, this means in particular that the component or the polymer comprises at least 95% by weight. %, preferably at least 97% by weight and preferably at least 98% by weight. The remaining% by weight can in particular be formed by additives such as plasticizers, fillers, colors and the like.

According to a particularly preferred embodiment of the invention, the first, preferably low-melting, component of the multicomponent filaments or the bicomponent filaments is based on polyethylene and preferably consists of polyethylene or essentially polyethylene. According to a further preferred embodiment, the The first, preferably low-melting, component of the multicomponent filaments or bicomponent filaments is formed based on polypropylene and preferably consists of polypropylene or essentially polypropylene. Instead of polypropylene or in addition to polypropylene, at least one polypropylene copolymer can also be used within the scope of the invention.

According to a preferred embodiment of the invention, the second or further, in particular higher melting, component of the multicomponent filaments or bicomponent filaments is formed based on at least one polyester and/or based on polypropylene. Particularly preferably, the second or further, in particular higher melting, component of the multicomponent filaments or bicomponent filaments consists of at least one polyester and/or polypropylene. For the second or further component, at least one polypropylene copolymer can be used instead of polypropylene or in addition to polypropylene and preferably at least one polyester copolymer can also be used instead of the polyester or in addition to the polyester. Suitable polyesters are in particular polyethylene terephthalate (PET) and/or polylactide (PLA), and a PET copolymer (Co-PET) is particularly suitable as a polyester copolymer. It is also within the scope of the invention that a polylactide copolymer (Co-PLA) is used as the first, in particular low-melting, component and polylactide (PLA) is used as the second or further, in particular higher-melting, component.

It is within the scope of the method according to the invention that the continuous filaments, preferably the crimped continuous filaments, are produced as multicomponent filaments or bicomponent filaments with a side-by-side configuration and/or with a core-sheath configuration, in particular with an eccentric core-sheath configuration or spun and the first, preferably low-melting, component is preferably the sheath component and the second, preferably higher-melting, component is the core component. If the continuous filaments are produced or spun as multicomponent filaments or bicomponent filaments with a core-sheath configuration, it is also fundamentally possible within the scope of the invention for it to be a centric core-sheath configuration.

If the continuous filaments or the crimped continuous filaments are produced or spun according to the preferred embodiment as multicomponent filaments or bicomponent filaments with an eccentric core-sheath configuration, it is within the scope of the invention that both the sheath of the filaments and the core of the filaments - in Filament cross section seen - is circular. According to a further preferred embodiment of the invention, the multicomponent filaments or bicomponent filaments are produced or spun as multicomponent filaments or bicomponent filaments with an eccentric core-sheath configuration and the core of these filaments - seen in the filament cross section - is designed in the shape of a segment of a circle and has an arcuate peripheral section with respect to its circumference as well as a linear circumferential section, so that a D-shape of the core - seen in the filament cross section - results.

If the continuous filaments or the crimped continuous filaments are produced or spun in the context of the method according to the invention as multicomponent filaments or bicomponent filaments with at least one first, preferably low-melting, component described above and at least one second or further, preferably higher-melting, component described above, is the proportion of the first, preferably low-melting, component of the multicomponent filaments or bicomponent filaments in the at least one nonwoven web of the nonwoven fabric is 10 to 90% by weight, preferably 20 to 70% by weight, preferably 30 to 50% by weight - based on Components of the multicomponent filaments or bicomponent filaments.

The design of the fibers of the nonwoven fabric as multicomponent filaments or bicomponent filaments, in particular with a first, preferably low-melting component and a second or further, preferably higher-melting, component and further the preferred design of the multicomponent filaments or bicomponent filaments with a side-by-side configuration and /or core-sheath configuration, preferably with an eccentric core-sheath configuration, is based on the knowledge that the nonwoven material properties can be adjusted very flexibly through these components or configurations of the filaments and that, in particular in combination with the consolidation provided according to the invention with at least a calender roll and with at least one hot fluid main consolidation device, a nonwoven fabric can be produced with which a particularly advantageous compromise of the nonwoven material properties can be achieved to solve the technical problem according to the invention.

In this context, it has proven particularly useful that the surface temperature T1 of the at least one calender roll, in particular of the at least one calender or calender roll pair having the calender roll and/or the fluid temperature T2 of the at least one hot fluid main solidification device in relation to the melting temperature Tm of the first, preferably low-melting, component of the multicomponent filaments or bicomponent filaments, the following condition fulfills: (Tm-15°C) < T1 and/or T2 < (Tm+15°C), preferably (Tm-10°C) < T1 and/or T2 < (Tm+10°C), preferably (Tm -8°C) < T1 and/or T2 < (Tm+8°C), particularly preferred (Tm-7°C) < T1 and/or T2 < (Tm+7°C), very particularly preferred (Tm- 6°C) < T1 and/or T2 < (Tm+6°C), for example (Tm-5°C) < T1 and/or T2 < (Tm+5°C). As part of the method according to the invention, the melting temperature Tm of the first, preferably low-melting, component is determined in particular by means of dynamic differential calorimetry (DSC) according to ISO 11357-3:2011. Thus, the surface temperature T1 of the at least one calender roll and/or the fluid temperature T2 of the at least one hot fluid main solidification device preferably fulfills the condition listed above. The surface temperature T1 can preferably have the relationship to the fluid temperature T2 described above, so that T1 can preferably be higher than T2 or lower than T2 or can be identical to T2. If the hot fluid main solidification device, in particular the hot air main solidification device according to the preferred embodiment, is a hot air oven, then the fluid temperature corresponds, within the scope of the invention, in particular to the temperature of the hot air during this hot air solidification in the hot air oven.

According to a very preferred embodiment of the method according to the invention, an embossing pattern made up of a large number of embossings - preferably not connected to one another - is introduced into the nonwoven fabric by means of the at least one calender roll. It is within the scope of the invention that the calender roll is part of a calender which, according to a particularly preferred embodiment, has at least one pair of calender rolls and at least one, in particular one of the two calender rolls of the calender or the pair of calender rolls is preferably a calender roll for introducing an embossing pattern from a plurality of embossing in the nonwoven fabric. For this purpose, the calender roll preferably has a complementary embossing pattern of embossing elements. This will be explained in more detail below. The other or further roller of the calender or the pair of calender rollers is expediently a smooth roller with a smooth outer surface. As part of the method according to the invention, the nonwoven fabric is therefore preferably solidified with a calender which has at least one calender roll for introducing an embossed pattern from a plurality of embossments into the nonwoven fabric and more preferably at least one smooth roll. Then the embossed pattern is preferably introduced into the nonwoven fabric only from one side of the nonwoven fabric. However, the embossed pattern is then preferably present in the resulting nonwoven on both sides of the nonwoven, with the embossing depth being distributed differently on the two sides of the nonwoven. It is within the scope of the invention that when using a calender consisting of at least one pair of calender rolls, one of the calender rolls having embossing elements for introducing an embossing pattern made up of a plurality of embossments into the nonwoven fabric and one calender roll being designed as a smooth roll, the two calender rolls for solidifying the nonwoven fabric have different surface temperatures. It is preferred that the calender roll with the embossing elements has the higher surface temperature. In the case of different temperatures of the calender rolls, the surface temperature T1 described above means in particular the temperature of the calender roll with embossing elements.

In the context of the invention, the term embossing means in particular a compressed point of the nonwoven fabric, at which the nonwoven fabric has a smaller thickness compared to its non-embossed areas and at which the fibers of the nonwoven fabric are at least partially formed, preferably by the action of pressure and/or temperature are connected or merged with each other. According to a very particularly preferred embodiment of the method according to the invention, the embossings each have an embossing area of 0.05 to 0.6 mm ² , preferably of 0.06 to 0.4 mm ² , preferably of 0.07 to 0.25 mm ² , particularly preferably from 0.08 to 0.15 mm ² and very particularly preferably from 0.09 to 0.12 mm ² . It is within the scope of the invention that the embossings each have an embossing area of less than 0.3 mm ² , preferably less than 0.2 mm ² , preferably less than 0.18 mm ² , particularly preferably less than 0.15 mm ² , very particularly preferably less than 0.12 mm ² , for example less than 0.1 mm ² . These embodiments are based on the knowledge that with an embossing pattern made of embossings of this special design and in particular with the relatively small embossing area, the optical perceptibility of the embossing pattern by the human eye can be at least significantly reduced, so that impairment of the optical properties of the resulting nonwoven fabric is almost completely avoided can be.

In the context of the invention, the term embossed pattern means in particular the pattern resulting from the large number of embossings on the nonwoven fabric. The embossed pattern can be a regular and/or an irregular embossed pattern. It is preferred that the embossing pattern is a regular embossing pattern. The individual embossings are then preferably distributed at regular intervals, preferably at identical intervals, on the resulting nonwoven fabric. Further preferably, the embossing surface of the individual embossings of the embossing pattern is the same size or essentially the same size. It has been proven that the geometry of the embossing surfaces of the individual embossings is identical or essentially identical. Very particularly preferably, the embossed pattern has the same or equally sized embossments or essentially the same or equally sized embossments with a homogeneous distribution of embossments of the same geometry or of essentially the same geometry. In principle, however, it is also possible for the individual embossings of the embossing pattern to have a different size and/or a different geometry from one another and/or for the embossings to be arranged in an irregular embossing pattern on the nonwoven fabric. In the context of the invention, the geometry of the embossing also means in particular the geometry of the embossing surfaces of the embossings in the top view.

In the context of the invention, the embossing surface of an embossing means, in particular, the embossed surface of an embossing, whereby when determining the size of the embossing surface, a material protrusion or material bead that may form during the course of the pressing or embossing process and at least partially enclose the embossing is in particular not part of the embossing surface an embossing. In the case of an embossing or embossing surface with a punctiform or circular geometry in plan view, the embossing surface of the embossing corresponds, for example, to the surface area of the punctiform or circular embossing, with the material protrusion or the material bead possibly surrounding the embossing not being added to the embossing surface of the embossing . The fact that the embossings of the nonwoven fabric according to the invention each have an embossing surface in the area specified above means in the context of the invention in particular that at least 95%, preferably at least 97%, of all embossings of the nonwoven fabric have an embossing surface in the specified area. Particularly preferably, all embossings of the nonwoven material have an embossing surface in the specified area. Within the scope of the invention, the embossing surface of an embossing can be determined in particular by reflected light or transmitted light 2D microscopy, and/or by scanning electron microscopy (SEM) and/or by micro-computed tomography (µCT). In the corresponding image evaluation, a geometry underlying the embossing surface geometry or corresponding or essentially corresponding to the embossing surface geometry is preferably used as a basis and placed over the individual optically imaged embossing surfaces of the embossings for evaluation.

It is within the scope of the method according to the invention that the embossed pattern is produced with the proviso that the smallest distance d between two embossments of the embossed pattern is 0.6 to 3.0 mm, preferably 0.8 to 2.5 mm, preferably 0.9 to 2.0 mm, particularly preferably 0.95 to 1.8 mm and very particularly preferably 1.0 to 1.5 mm. The smallest distance d between two embossings of the embossing pattern is expediently at least 0.6 mm, in particular at least 0.8 mm, preferably at least 1.0 mm, particularly preferably at least 1.4 mm and very particularly preferably at least 2.0 mm. Smallest distance d between two embossings of the embossing pattern means in particular the smallest distance d between two immediately adjacent embossings of the embossing pattern, i.e. preferably the smallest distance between one embossing and the embossing of the embossing pattern closest to it. In addition, the smallest distance d between two embossings of the embossed pattern refers in particular to the smallest distance between the embossing boundaries of two embossings, i.e. to the smallest distance between the two embossings along the non-embossed surface of the nonwoven fabric in between. This embodiment is based in particular on the knowledge that the visual perceptibility of the embossed pattern can be further reduced. The smallest distance between two embossings of the embossing pattern described above preferably refers to at least 95%, preferably to at least 97% of all embossings of the nonwoven fabric. Particularly preferably, the described smallest distance between two embossings refers to all embossings of the nonwoven fabric.

A further preferred embodiment of the method according to the invention is characterized in that the embossed pattern is produced with the proviso that the proportion of the total embossed area of the embossed pattern to the total surface of the nonwoven is 2 to 15%, preferably 2.5 to 12%, preferably 3 to 8% , particularly preferably 3.5 to 6% and very particularly preferably 3.8 to 5.2%. It is within the scope of the invention that the embossed pattern is produced with the proviso that the proportion of the total embossed area of the embossed pattern to the total surface of the nonwoven fabric is less than 10%, preferably less than 8%, preferably less than 6.5%, particularly preferably less than 5.5% and most preferably less than 5%. Through these above Proportions of the total embossed area of the embossed pattern to the total surface of the nonwoven fabric can further reduce the visual perceptibility of the embossed pattern from embossing. In this context, the total embossing area of the embossing pattern means in particular the sum of all embossing areas of the embossing pattern. Total surface of the nonwoven fabric within the scope of the invention, in particular the entire nonwoven fabric surface including the embossed and non-embossed areas.

It is within the scope of the method according to the invention that the calender line load of the calender roll or the calender is 4 N/mm to 60 N/mm, preferably 10 N/mm to 40 N/mm, particularly preferably 15 N/mm to 35 N/mm, very particularly preferably 20 N/mm to 30 N/mm. More preferably, the calender line load is 2 to 20 N/mm, preferably 3 to 15 N/mm, preferably 4 to 8 N/mm per percent of the total embossed area of the embossed pattern explained above on the total surface of the nonwoven.

In the context of the method according to the invention, it is particularly preferred that a nonwoven fabric is produced with at least two nonwoven webs of fibers, for which first fibers are produced by at least one first fiber production device, in particular by at least one first spinning beam, and then on the storage device, in particular on the Storage screen belt, are deposited to form the non-woven web, with second fibers being produced by at least one second fiber producing device, in particular by at least one second spinning beam, and then deposited on the first non-woven web to form the second non-woven web, and with the aggregate consisting of the at least two non-woven webs or the non-woven fabric at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll, and wherein the nonwoven fabric is also solidified or main solidified with at least one hot fluid main solidification device, in particular with at least one hot air main solidification device. It has already been mentioned above that in the context of such an embodiment, at least one pre-consolidation device, preferably at least one hot fluid pre-consolidation device, preferably at least one hot air pre-consolidation device, is expediently connected downstream of each fiber production device or each spinning beam, in particular immediately downstream, and that the deposited nonwoven webs are preferred In each case, before solidification or main solidification of the nonwoven material, they are first pre-solidified with the respective pre-solidification device.

If, as part of the method according to the invention, a nonwoven fabric with at least two nonwoven webs is produced from fibers, it is particularly preferred that the fibers are produced as continuous filaments, in particular as crimped continuous filaments, and are each laid down as a spunbond nonwoven web. The properties of the fibers or continuous filaments of the various nonwoven webs or nonwoven layers of the resulting nonwoven material can differ. For example, the continuous filaments of the first nonwoven web produced with a first spinning beam can have a lower average titer than the continuous filaments of the second nonwoven web produced with the second spinning beam, so that a titer gradient results, so to speak. It has proven useful that the fibers of at least one nonwoven web or nonwoven layer assigned to an outer surface of the nonwoven material are produced as crimped endless filaments and/or as short fibers. In this way, the softness of the nonwoven material in particular can be improved and the bending stiffness can be reduced.

To solve the technical problem, the invention also teaches a device for producing a nonwoven fabric with at least one nonwoven web made of fibers, in particular for carrying out a method described above, wherein the device has at least one fiber production device, in particular at least one spinning beam, and at least one storage device, in particular at least one Deposition screen belt, for depositing the fibers into the nonwoven web, wherein furthermore at least one calender roll, in particular a calender or pair of calender rolls having the calender roll, is provided for solidifying the nonwoven material and in addition at least one hot fluid main solidification device, in particular at least one hot air main solidification device Solidification or main solidification of the nonwoven fabric is present.

It is within the scope of the invention that the device has at least one pre-consolidation device, preferably at least one hot fluid pre-consolidation device, preferably at least one hot air pre-consolidation device, for pre-consolidation of the nonwoven, which is connected downstream, in particular immediately downstream, of the at least one fiber producing device or the at least one spinning beam and wherein the at least one hot fluid pre-solidification device or the at least one hot air pre-solidification device is particularly preferably designed as a hot air knife and / or as a hot air field.

The storage sieve belt of the device according to the invention is expediently endless all-round storage sieve belt. It is within the scope of the invention that the at least one fiber producing device or the at least one spinning beam is designed to produce a spunbond nonwoven web made of endless filaments, in particular of crimped endless filaments. If the nonwoven fabric according to one embodiment of the invention is designed as a nonwoven laminate made of at least two nonwoven webs or nonwoven fabric layers, it is within the scope of the invention that at least two fiber production devices, in particular at least two spinning beams, are present and that preferably all fiber production devices or spinning beams are used to produce spunbond -Nonwoven webs are made from continuous filaments, in particular from crimped continuous filaments. Very particularly preferably, the at least one fiber generating device or the at least one spinning beam, preferably all fiber generating devices or all spinning beams of the device according to the invention, is set up to produce multicomponent filaments or bicomponent filaments. It is also within the scope of the invention that the device is designed to produce at least one nonwoven web made of crimped endless filaments. Preferably, at least one fiber producing device or at least one spinning beam is set up to produce crimped endless filaments. When using several spinning beams for the device according to the invention, at least one spinning beam or at least two spinning beams or all spinning beams are set up for the production of crimped endless filaments.

A very expedient embodiment of the invention is characterized in that for the fibers or continuous filaments spun with at least one fiber production device or with at least one spinning beam, at least one cooling device for cooling the fibers or filaments and at least one stretching device connected to the cooling device for stretching the fibers or filaments is provided. Advantageously, at least one diffuser is connected to the stretching device in the direction of flow of the fibers or filaments. A highly recommended embodiment of the invention is characterized in that the unit consisting of the cooling device and the stretching device is designed as a closed unit and that no other air is supplied from outside into this unit other than the supply of cooling air in the cooling device. The fibers or filaments leaving the diffuser are expediently deposited directly on the storage device or on the storage sieve belt.

According to a preferred embodiment of the device according to the invention, the at least one calender roll, in particular the calender or the pair of calender rolls having the calender roll, is arranged in front of or behind the at least one hot fluid main consolidation device in the conveying direction F of the nonwoven material. According to a preferred embodiment, the at least one hot fluid main solidification device is arranged in the conveying direction F of the nonwoven in front of the calender roll and in particular in front of the calender having the calender roll. According to a particularly preferred embodiment, the at least one hot fluid main solidification device is arranged in the conveying direction F of the nonwoven behind the calender roll and in particular behind the calender having the calender roll.

According to a further preferred embodiment of the device according to the invention, the at least one calender roll has a complementary embossing pattern of embossing elements for introducing an embossing pattern of a plurality of embossings into the nonwoven fabric. With such a calender roll with a complementary embossing pattern of embossing elements, the embossing pattern of embossings already described above can be introduced into the nonwoven fabric. In addition to this calender roll, the calender or the pair of calender rolls expediently has a second or further calender roll, which is designed as a smooth roll with a smooth outer surface, in order to introduce an embossing pattern of embossments into the nonwoven fabric.

It has proven particularly useful that the embossing elements of the complementary embossing pattern of the calender roll each have a pressing surface of 0.05 to 0.6 mm ² , preferably 0.06 to 0.4 mm ² , more preferably 0.07 to 0.25 mm ² , particularly preferably from 0.08 to 0.15 mm ² , very particularly preferably from 0.09 to 0.12 mm ² . In the context of the invention, pressing surface means in particular the surface of the embossing elements of the calender roll intended for producing the embossing surface of the embossings. If the embossing elements of the calender roll are designed, for example, as cylindrical embossing elements to produce an embossing surface with a punctiform or circular geometry in plan view, the pressing surface of the embossing elements corresponds in particular to the surface of the top of the cylinder. If the embossing elements of the calender roll are designed to produce an embossing surface with a punctiform or circular geometry in plan view, for example in the shape of a truncated cone - i.e. with a flank angle - the pressing surface of the embossing elements corresponds in particular to the top surface of the truncated cone. One embodiment of the invention uses several flank angles for the embossing elements, with the embossing elements preferably having smaller flank angles in the area intended for contact with the nonwoven material than further in the direction of the base of the Calender roll. The flank angle gradation can take place gradually or continuously. Within the scope of the invention, the calender roll for introducing an embossing pattern of embossing elements into the nonwoven fabric is designed in particular with regard to its complementary embossing pattern or with regard to the arrangement and design of the embossing elements in such a way that an embossing pattern with the parameters or properties described above can be realized in the nonwoven fabric can.

It is within the scope of the invention that the embossing elements of the complementary embossing pattern of the at least one calender roll each have an embossing height in the range from 0.3 to 1.2 mm, preferably from 0.4 to 0.9 mm, particularly preferably from 0.5 to 0 .8 mm. Embossing height means in particular the height difference between the pressing surface of an embossing element and the base of the calender roll. This embodiment is based on the knowledge that compaction of the nonwoven material can be at least largely minimized during a calendering process with such a calender roll.

To solve the technical problem, the invention further teaches a nonwoven fabric which is produced by a method described above and/or with a device described above.

According to a particularly preferred embodiment of the nonwoven fabric according to the invention, the nonwoven fabric has an embossed pattern made up of a large number of - preferably not connected to one another - embossments, the embossments preferably each having an embossed area of 0.05 to 0.6 mm ² , preferably of 0.06 to 0 .4 mm ² , more preferably from 0.07 to 0.25 mm ² , particularly preferably from 0.08 to 0.15 mm ² and very particularly preferably from 0.09 to 0.12 mm ² and/or where the Embossed surfaces of the embossings in the top view preferably have at least one geometry selected from the group: “point-shaped or circular, elliptical, square, rectangular, diamond-shaped, polygonal, linear, wavy”. It is preferred that the embossing surfaces or the embossings of the embossing pattern each have the same or essentially the same geometry. In principle, however, it is also within the scope of the invention that the embossed pattern has embossing surfaces or embossings of different geometries. A particularly preferred embodiment of the invention is characterized in that the embossing surfaces of the embossings or all embossings are point-shaped or circular in plan view. In the context of the invention, the geometry of the embossing also means in particular the geometry of the embossing surfaces of the embossings in the top view.

A preferred embodiment of the nonwoven fabric according to the invention is characterized in that the aspect ratio of the embossing surface of the embossings is in each case less than 4, preferably less than 3, particularly preferably less than 2, for example equal to 1. Aspect ratio of the embossing surface in this context means in particular the ratio of the greatest length or longitudinal extent of the embossing surface of an embossing to the greatest width or width extent of the embossing surface of the embossing and, for example, the ratio of the lengths of the axes of symmetry. In the case of a point-shaped or circular geometry of the embossing surface of an embossing in the top view, the aspect ratio is, for example, equal to 1. In the case of an elliptical geometry of the embossing surface of an embossing in the top view, the aspect ratio corresponds, for example, to the ratio of the length of the major axis or semi-major axis to the length the minor axis or semi-minor axis of the ellipse. In the case of a geometry of the embossing surface of an embossing which is rectangular in plan view, the aspect ratio corresponds, for example, to the ratio of the length of the rectangle to the width of the rectangle. In the case of a diamond-shaped geometry of the embossing surface of an embossing in plan view, the aspect ratio corresponds, for example, to the ratio of the length of the longer diagonal to the length of the shorter diagonal of the diamond. In the case of a square geometry of the embossing surface of an embossing in plan view, the aspect ratio is equal to 1. In the case of curved lines, the aspect ratio of the enclosing rectangle preferably describes the aspect ratio of the embossing surface.

It is preferred that the nonwoven fabric has a basis weight of less than 200 g/m ² , in particular of less than 150 g/m ² , preferably of less than 100 g/m ² , preferably of less than 75 g/m ² , particularly preferred of less than 50 g/m ² and very particularly preferably of less than 30 g/m ² and/or that the nonwoven has a thickness of 0.1 to 1.0 mm, preferably 0.15 to 0.8 mm, preferably from 0.2 to 0.65 mm, particularly preferably from 0.25 to 0.55 mm. It is very particularly preferred that the basis weight of the nonwoven is 10 g/m ² to 80 g/m ² , preferably 15 g/m ² to 60 g/m ² , preferably 15 g/m ² to 30 g/m ² . It is also within the scope of the invention that the nonwoven material has a thickness h of at least 0.3 mm, in particular of at least 0.45 mm, preferably of at least 0.55 mm, preferably of at least 0.6 mm, particularly preferably of at least 0.625 mm. Thickness h means in particular the largest thickness or total thickness of the nonwoven across, in particular perpendicular or essentially perpendicular to its flat extent in the non-embossed areas of the nonwoven fabric. The thickness or total thickness h of the nonwoven fabric is measured using the WRT 120.6(05) option A method.

• Es wird als Testgerät insbesondere das Gerät „SDL Atlas M235 Martindale Tester“ verwendet. Das Vorgehen zur Ermittlung der Abriebfestigkeit basiert vorzugsweise auf WSP20.5(05), wobei insbesondere die folgenden Abweichungen zu WSP20.5(05) vorgesehen werden: Die Oberfläche (oben/unten) wird separat geprüft; mindestens 10, bevorzugt mindestens 20 Prüfungen werden pro Muster und Oberfläche durchgeführt, wobei die Prüflinge gleichmäßig aus der Fläche der Probe gewonnen werden, das Endergebnis ist der arithmetische Mittelwert. Die Prüflinge sind aus einer repräsentativen Position zu gewinnen, also beispielsweise nicht alleine vom Rand, da der Test bzw. die Abweichungen im Ergebnis nicht durch makroskopische Abweichungen, wie durch schlechte Prozesskontrolle, sondern nur von typischen (lokalen) Schwankungen beeinflusst werden soll; die getestete Probe wird auf Standardfilz gespannt und im unteren Halter montiert; als bewegte obere Reibfläche wird der gleiche Vliesstoff verwendet mit der zu testenden Seite gegeneinander, dieses Stück wird zusammen mit dem PU-Schaumstoffflicken (z.B. von SDL Atlas) befestigt; 9 kPa Andruck; 32 Zyklen, das heißt zwei volle Runden der Lissajous Figur; nach jeder der Prüfungen werden das Paar (Prüfling und obere Reibfläche) ausgetauscht;

die Proben werden mit den Noten 1 bis 5 bewertet, wobei 1 die Bestnote ist. Wenn beispielsweise der Mittelwert auf der Oberseite eine 1 und auf der Unterseite eine 3 ergibt, wird die Probe insgesamt mit 1 bewertet. Bewertet werden nur die Veränderungen im Vlies, wenn das Vlies vorher ähnliche Defekte aufweist sind diese zu übersehen. Hier sind etwa Fasersträhnen - Gruppen oder Bündel von Fasern auf der Oberfläche - gemeint. Weist ein Prüfling diese Fehler von vornherein deutlich auf, so ist der Prüfling im Zweifel auszuschließen.

• Note 1: Praktisch keine Veränderung von oben betrachtet. Die Oberfläche darf leicht angelöst werden, dabei dürfen die Filamente sich nur lockern und keine größeren bzw. längeren Zusammenballungen erzeugen. Von der Seite betrachtet darf die Florhöhe der losen Filamente 5 mm nicht überschreiten. Einzelne Filamente bzw. Filamente dürfen zu einem kleinen Ball <2 mm Durchmesser zusammengeschoben werden.
• Note 2: zusätzlich zu dem oberen Schadensbild (Note 1): Filamente werden gelockert und mit Nachbarfilamenten zu einem länglichen Agglomerat verfilzt. Diese Filamentgruppen werden „Strähnen“ oder „string bzw. bundle“ genannt. Diese Strähnen sind 5 bis 40 mm lang und mind. alle 10 mm Länge mit dem Untergrund verbunden. Eine Strähne ist max. 5 mm hoch (steht 5 mm über der Oberfläche) und max. 2 mm breit.
• Note 3: Die obigen „Strähnen“ sind nicht mehr entlang ihrer Länge mit dem Untergrund verbunden - mögliche Verbindungen sind >10 mm untereinander entfernt bzw. die Strähnen hier sind nur noch am Start- und Endpunkt mit der Probe verbunden. Es ist möglich, diese Strähne z.B. mit einer Nadel anzuheben und zu verschieben.
• Note 4: Die Strähnen sind mit Nachbarsträhnen zu einem Netzwerk verbunden. „Spinnennetz“ (spider web).
• Note 5: Die Probe ist weiter zerstört, erste Lochbildung ist aufgetreten.

It is within the scope of the invention that the nonwoven fabric has an abrasion resistance of at least Class 2 according to Martindale, preferably of Class 1 according to Martindale and/or that the nonwoven fabric has a maximum flexural rigidity with a cantilever of a maximum of 100 mm, preferably a maximum of 90 mm of a maximum of 80 mm, particularly preferably of a maximum of 70 mm and very particularly preferably of a maximum of 65 mm. This embodiment is based on the knowledge that the nonwoven material is then characterized by a very satisfactory abrasion resistance and/or that the nonwoven material has an advantageously low bending stiffness and, in particular, improved drapability compared to the known measures or nonwoven materials. This advantageously contributes to solving the technical problem and in particular to a compromise between optimal nonwoven material properties. The abrasion resistance of the nonwoven fabric is determined in the context of the invention in particular with a Martindale abrasion tester according to the following test method:

• In particular, the “SDL Atlas M235 Martindale Tester” device is used as a test device. The procedure for determining abrasion resistance is preferably based on WSP20.5(05), with the following deviations from WSP20.5(05) being provided in particular: The surface (top/bottom) is tested separately; at least 10, preferably at least 20 tests are carried out per sample and surface, with the test specimens being obtained evenly from the surface of the sample; the final result is the arithmetic mean. The test specimens must be obtained from a representative position, for example not just from the edge, since the test or the deviations in the result should not be influenced by macroscopic deviations, such as poor process control, but only by typical (local) fluctuations; the tested sample is stretched on standard felt and mounted in the lower holder; The same non-woven material is used as the moving upper friction surface with the side to be tested against each other, this piece is attached together with the PU foam patch (e.g. from SDL Atlas); 9 kPa pressure; 32 cycles, that is, two full rounds of the Lissajous figure; after each of the tests, the pair (test specimen and upper friction surface) are replaced;

The samples are graded from 1 to 5, with 1 being the best grade. For example, if the average is a 1 on the top and a 3 on the bottom, the sample is given a score of 1 overall. Only the changes in the fleece are evaluated; if the fleece previously had similar defects, these can be overlooked. This refers to fiber strands - groups or bundles of fibers on the surface. If an examinee clearly shows these errors from the outset, the examinee must be ruled out in case of doubt.

• Grade 1: Virtually no change viewed from above. The surface may be slightly loosened, but the filaments may only loosen and not create larger or longer agglomerations. Viewed from the side, the pile height of the loose filaments must not exceed 5 mm. Individual filaments or filaments may be pushed together to form a small ball <2 mm in diameter.
• Grade 2: in addition to the above damage pattern (grade 1): filaments are loosened and matted with neighboring filaments to form an elongated agglomerate. These groups of filaments are called “strands” or “string or bundle”. These strands are 5 to 40 mm long and are connected to the substrate at least every 10 mm in length. A strand is a maximum of 5 mm high (stands 5 mm above the surface) and a maximum of 2 mm wide.
• Note 3: The above “strands” are no longer connected to the substrate along their length - possible connections are >10 mm apart or the strands here are only connected to the sample at the start and end points. It is possible to lift and move this strand with a needle, for example.
• Note 4: The strands are connected to neighboring strands to form a network. “Spider web”.
• Grade 5: The sample is further destroyed and the first holes have formed.

Within the scope of the invention, the bending stiffness of the nonwoven fabric is determined in particular using the method “WSP 90.1(05) Standard Test Method for Stiffness of Nonwoven: Fabrics Using the Cantilever Test”.

It is within the scope of the invention that the strength of the nonwoven fabric in the machine direction (MD direction) is at least 8 N/5 cm, in particular at least 10 N/5 cm, preferably at least 15 N/5 cm, preferably at least 17.5 N/5 cm, particularly preferably at least 20 N/5 cm, very particularly preferably at least 22.5 N/5 cm. In the context of the invention, machine direction (MD direction) means in particular the conveying direction F of the Nonwoven material on the storage device. Within the scope of the invention, the strength of the nonwoven fabric in the machine direction is determined in particular using the following method: “Determination of tensile strength (based on Edana 20.2-89)”: in N/5 cm; with 50 mm sample width; 100 mm clamping length; 200 mm/min testing speed.

According to a preferred embodiment of the invention, the nonwoven fabric is designed as a nonwoven laminate made of at least two nonwoven webs or nonwoven fabric layers.

The invention is based on the finding that the method according to the invention can be used to provide a nonwoven fabric which is characterized by an optimal compromise of advantageous mechanical properties, sufficient thickness or voluminousness, low rigidity or good drapability and advantageous abrasion resistance. Through the inventive combination of solidification with at least one calender roll, in particular with at least one calender or pair of calender rolls having the calender roll, and with at least one hot fluid main solidification device, an optimal compromise between these properties can be achieved. It should be emphasized that these nonwoven properties can be achieved in a very functionally reliable manner within the context of the method according to the invention and can nevertheless be achieved with relatively simple measures. The method according to the invention is also characterized by optimal flexibility. According to a preferred embodiment, the nonwoven material properties can be further optimized by the temperature relationships between the calender roll or calender and the hot fluid main consolidation device, as well as by the components of the fibers or filaments and by the configuration of the fibers or filaments. If, according to the preferred embodiment, an embossing pattern made up of a large number of embossings and, according to a very particularly preferred embodiment, an embossing pattern made up of a large number of embossings with a relatively small embossing area is introduced into the nonwoven fabric, impairment of the optical properties of the resulting nonwoven fabric can also be almost completely avoided , whereby the nonwoven fabric nevertheless has the advantageous mechanical properties resulting from such a calendering process or embossing process. In summary, it can be stated that within the scope of the invention an optimal compromise can be achieved from the nonwoven material properties explained above. Due to the flexibility of the method, for example with regard to the temperatures used for the solidification steps or with regard to the design of the fibers or filaments, the nonwoven material properties can be further optimized according to the preferred embodiments of the method according to the invention.

• Bei den folgenden drei Ausführungsbeispielen unterscheidet sich insbesondere nur die Verfestigung bzw. Hauptverfestigung der Vliesstoffe, wobei für alle drei Ausführungsbeispiele (Beispiele 1 bis 3) zunächst die folgenden Parameter und Ausführungen gelten:

The invention is explained in more detail below using exemplary embodiments:

• In the following three exemplary embodiments, only the consolidation or main consolidation of the nonwovens differs, with the following parameters and specifications initially applying to all three exemplary embodiments (Examples 1 to 3):

It is a spunbond nonwoven fabric made from two spunbond nonwoven webs or nonwoven layers that were spun with a first spinning beam and a second spinning beam. The weight per unit area of the resulting nonwoven was 20 g/m ² . The depositing sieve belt speed was 315 m/min. The fibers were each created or deposited as crimped continuous filaments in the form of bicomponent filaments, with the filaments of the first spinning beam having an eccentric core-sheath configuration with a D-shape of the core and the filaments of the second spinning beam having a side-by-side configuration had. Polyethylene was used as the first component for the filaments of the first spinning beam (DOW Aspun 6850 + 2% by weight of white color additive). Polypropylene was used as the second component for the filaments of the second spinning beam (Exxon PP3155 + 5 wt.% Borealis HL712FB + 1 wt.% lubricant additive). The mass ratio of the first component to the second component was 50:50. Polyethylene was used as the first component for the filaments of the second spinning beam (DOW Aspun 6834 + 2% by weight of white color additive). Polypropylene was used as the second component for the filaments of the second spinning beam (Exxon PP3155 + 1 wt.% Borealis HL712FB + 1 wt.% lubricant additive). The mass ratio of the first component to the second component was 40:60. The throughput for the first bar was 145 kg/h/m and for the second bar it was 180 kg/h/m.

After the first beam, pre-consolidation was carried out with a hot air knife (650 m ³ /h/m; 145 °C, 90 mm length) and pre-consolidation with a hot air field (1.5 m/s; 135 °C, 900 mm length) . After the second beam, pre-solidification took place with a hot air knife (625 m ³ /h/m; 145 °C, 90 mm overall length) and solidification or main solidification with a hot air field with three different successive temperature zones (length of each temperature zone 1200 mm each) , which were operated at different temperatures in the different exemplary embodiments, as explained below. This was then carried out as indicated Solidification with a calender. The filaments of the first nonwoven web or nonwoven layer had an average titer of 1.3 denier. The filaments of the second nonwoven web or nonwoven layer had an average titer of 2.0.

For the consolidation or main consolidation of the nonwovens of the exemplary embodiments (Examples 1 to 3), the following common conditions and specifications initially apply: The calender had a total pressing area of the embossing elements of 4% and 41.7 Fig/cm ² , as well as embossing elements with a circular shape pressing surface; the pressing surface of the embossing elements had a diameter of 0.35 mm and thus a pressing surface of approximately 0.096 mm ² ; the distance between the embossing elements, determined in analogy to the smallest distance d between two embossings described above, was 1.2 mm; The calender had an upper calender roll with embossing elements and a lower calender roll with a smooth surface. A hot air main solidification device in the form of an Omega oven with a diameter of 1414 mm and an active, flow-through length of 3500 mm was arranged behind the calender in the conveying direction F of the nonwoven material (air speed: 0.8 m/s). The cantilever and Martindale values reported below were measured as described above; In the Martindale specifications, “top” is the side assigned to the calender roll with embossing elements and “bottom” is the side assigned to the depositing wire belt.

Example 1:

Solidification or main solidification with the hot air field after the second spinning beam with three different successive temperature zones: 120°C/130°C/80°C; Calender surface temperature: 129°C for the calender roll with embossing elements, 123°C for the smooth roll; Line load calender: 30 N/mm; Omega oven temperature: 80°C.

This resulted in a nonwoven fabric with a machine direction (MD) strength of 20.7 N/5 cm, a thickness of 0.45 mm and a cantilever of 65 mm, as well as an abrasion resistance of Class 1 (top)/Class 1 ( below) to Martindale. This resulted in particular in a product that is characterized by a very advantageous abrasion resistance, a very advantageously low cantilever value, sufficient strength and a satisfactory thickness.

Example 2:

Solidification or main solidification with the hot air field after the second spinning beam with three different successive temperature zones: 120°C/130°C/130°C; Calender surface temperature: 121°C for the calender roll with embossing elements, 127°C for the smooth roll; Line load calender: 30 N/mm; Omega oven temperature: 128°C.

This resulted in a nonwoven fabric with a machine direction (MD) strength of 26.6 N/5 cm, a thickness of 0.39 mm and a cantilever of 77 mm, as well as an abrasion resistance of Class 1 (top)/Class 1 ( below) to Martindale. This resulted in particular in a product that is characterized by a very advantageous abrasion resistance, an advantageously low cantilever value, a very advantageous strength and a sufficient thickness.

Example 3 (prior art or not according to the invention):

Solidification or main solidification with the hot air field after the second spinning beam with three different successive temperature zones: 120°C/130°C/130°C; Calender: Open, i.e. no contact with non-woven material or no solidification with the calender; Omega oven temperature: 138°C; therefore no combined solidification with the calender.

The result was a nonwoven fabric with a machine direction (MD) strength of 21.3 N/5 cm, a thickness of 0.53 mm and a cantilever of 105 mm, and an abrasion resistance of class 2.5 (top)/class 1 (down) to Martindale. This resulted in particular in a product that is characterized by disadvantageous abrasion resistance, a disadvantageous cantilever value, sufficient strength and an advantageous thickness on the nonwoven side.

• 1 einen Vertikalschnitt durch eine erfindungsgemäße Vorrichtung
• 2 einen Vertikalschnitt durch einen Teil der Vorrichtung gemäß 1
• 3 einen erfindungsgemäßen Vliesstoff in der Draufsicht
• 4 einen Querschnitt entlang A-A gemäß 1.

The invention is explained in more detail below using a drawing that only shows an exemplary embodiment. It shows in a schematic representation:

• 1 a vertical section through a device according to the invention
• 2 a vertical section through part of the device 1
• 3 a nonwoven fabric according to the invention in plan view
• 4 a cross section along AA according to 1 .

The 1 shows a device 14 according to the invention for carrying out the method according to the invention and for producing a nonwoven fabric 1 with two nonwoven webs 2, 2 'made of crimped endless filaments 10. The device preferably has two spinning beams 3, 3' in the exemplary embodiment, which are preferred and in the exemplary embodiment are set up to produce a spunbond nonwoven web 2, 2 'from crimped endless filaments 10 in the form of bicomponent filaments. According to the preferred embodiment, there is also an endlessly rotating storage screen belt 4 for depositing the endless filaments 10 into the nonwoven web 2, 2 '. The device 14 preferably has, and in the exemplary embodiment, a calender roll 5 for introducing an embossed pattern 11 ( 3 and 4 ) from a large number of unconnected embossments 12 in the nonwoven fabric 1. This calender roll 5 is preferred and in the exemplary embodiment is part of a calender 6 made up of a pair of calender rolls 5, 7. Preferably and in the exemplary embodiment, the calender roll 5 of the calender 6 has a complementary embossing pattern 15 made up of embossing elements 16, each of which preferably has a pressing surface 17 of 0.05 to 0 .6 mm ² . Pressing surface 17 means in particular the surface of the embossing elements 16 of the calender roll 5 intended for producing an embossing surface 13 of the embossings 12 of the nonwoven fabric 1. Preferably and in the exemplary embodiment according to 1 the embossing elements 16 of the calender roll 5 are truncated cone-shaped and the pressing surface 17 corresponds to the top surface of the truncated cone. The other or further calender roll 7 of the calender 6 is preferred and in the exemplary embodiment is designed as a smooth roll 7 with a smooth outer surface.

According to a particularly preferred embodiment and in the exemplary embodiment according to 1 the device 14 has a hot air main consolidation device 8, which is preferably arranged behind the calender roll 5 or behind the calender 6 in the conveying direction F of the nonwoven material. Preferably and in the exemplary embodiment, the hot air main solidification device 8 is designed as a hot air oven. Appropriately and in the exemplary embodiment, the device 14 also has two pre-solidification devices in the form of hot air pre-solidification devices 9, 9 '. The hot air pre-consolidation devices 9, 9 'are preferably and in the exemplary embodiment each arranged in the conveying direction F of the nonwoven fabric 1 in front of the calender roll 5 or in front of the calender 6. Preferably and in the exemplary embodiment according to 1 the hot air pre-consolidation devices 9, 9' are each connected immediately downstream of a spinning beam 3, 3' for pre-consolidation of the deposited nonwoven web 2, 2'. A first hot air pre-consolidation device 9 is preferably connected immediately downstream of a first spinning beam 3 in the conveying direction F of the nonwoven fabric 1 and is then followed by a second spinning beam 3 ', which is immediately followed by the second hot air pre-consolidation device 9'. The hot air pre-solidification devices 9, 9' are preferably set up as a hot air knife and/or as a hot air field.

As part of the method according to the invention and in the exemplary embodiment according to 1 a nonwoven web 2 made of crimped endless filaments 10 is first produced by the first spinning beam 3 and deposited on the storage screen belt 4. The nonwoven web 2 is then preferred and, in the exemplary embodiment, pre-solidified by means of the hot air pre-consolidation device 9. Afterwards, a second non-woven web 2 'made of crimped endless filaments 10 is expediently produced by the second spinning beam 3' and deposited on the first non-woven web 2. The second non-woven web 2' or the aggregate of the first non-woven web 2 and the second non-woven web 2' is then recommended to be pre-solidified with the second hot air pre-consolidation device 9' and then preferably detached from the depositing wire belt 4 and fed to the calender 6 having the calender roll 5 . By means of the calender roll 5 of the calender 6, an embossed pattern 11 consisting of a plurality of embossments 12 is preferably introduced into the nonwoven fabric 1 and the nonwoven fabric 1 is expediently solidified. Subsequently, the solidification or main solidification of the nonwoven fabric 1 preferably takes place by means of the at least one hot air main solidification device 8.

The 2 shows the basic structure of a part of the device 14 according to the invention for producing a nonwoven web 2 according to the spunbond process comprising a spinner saver or the spinning beam 3 for spinning the continuous filaments 10 for the spunbond nonwoven web 2 from continuous filaments 10. The spinner saver or the Spinning beam 3 spun endless filaments 10 are introduced into a cooling device 18 with a cooling chamber 19.

Preferably and in the exemplary embodiment, air supply cabins 20, 21 arranged one above the other are arranged on two opposite sides of the cooling chamber 19. Air of different temperatures is preferably introduced into the cooling chamber 19 from the air supply cabins 20, 21 arranged one above the other.

It is recommended and in the exemplary embodiment that a stretching device 22 for stretching the endless filaments 10 is connected downstream of the cooling device 18 in the filament flow direction. Expediently and in the exemplary embodiment, the stretching device 22 has an intermediate channel 23 which connects the cooling device 18 to a stretching shaft 24 of the stretching device 22. Preferably and in the exemplary embodiment, the unit consisting of the cooling device 18, the intermediate channel 23 and the stretching shaft 24 is designed as a closed unit and, in addition to the supply of cooling air, takes place in the cooling device 18 no further air supply from outside into this unit.

Appropriately and in the exemplary embodiment, a diffuser 25, through which the endless filaments 10 are guided, adjoins the stretching device 22 in the direction of filament flow. After passing through the diffuser 25, the endless filaments 10 are preferably and in the exemplary embodiment deposited on a storage device designed as a storage sieve belt 4. The storage sieve belt 4 is preferred and in the exemplary embodiment is designed as an endlessly rotating storage sieve belt 4. It is within the scope of the invention that the storage sieve belt 4 is permeable to air, so that process air can be extracted from below through the storage sieve belt 4.

The 3 and 4 show a nonwoven fabric 1 according to the invention with at least one nonwoven web 2 made of fibers. In the exemplary embodiment, the nonwoven fabric 1 has two nonwoven webs 2, 2' made of endless filaments 10 and is in particular designed as a nonwoven laminate. The endless filaments 10 may preferably be crimped endless filaments 10 in the exemplary embodiment. Preferably and in the exemplary embodiment, the nonwoven fabric 1 is a spunbond nonwoven fabric with two spunbond nonwoven webs 2, 2 'made of crimped endless filaments 10. In the exemplary embodiment, the crimped continuous filaments 10 may be bicomponent filaments with an eccentric core-sheath configuration, with the sheath the continuous filaments 10 preferably consist or essentially consist of polyethylene and wherein the core of the continuous filaments 10 in particular consists or essentially consists of at least one polyester and/or polypropylene.

The 3 and 4 also show that the nonwoven fabric 1 has an embossed pattern 11, the embossed pattern 11 consisting of a plurality of unconnected embossments 12. The embossing pattern 11 is preferred and in the exemplary embodiment a regular embossing pattern 11, the individual embossings 12 of which are preferably arranged distributed on the nonwoven fabric 1 at regular intervals in the exemplary embodiment.

Within the scope of the invention and in the exemplary embodiment, the embossings 12 each have an embossing surface 13 of 0.05 to 0.6 mm ² . In the context of the invention and in the exemplary embodiment, embossing surface 13 of an embossing 12 means in particular the embossed surface of an embossing 12, whereby when determining the size of the embossing surface 13, the material excess which may form in the course of the pressing or embossing process and at least partially encloses the embossing 12 or material bead is not part of the embossing surface 13 of an embossing 12. This is particularly the case 4 can be seen in hatched representation. More preferably and in the exemplary embodiment, the embossing surface 13 of the individual embossings 12 of the embossing pattern 11 is the same size or essentially the same size. Preferably and in the exemplary embodiment according to the figures, the embossed surfaces 13 of the embossments 12 have a punctiform or circular geometry in plan view. Very particularly preferably and in the exemplary embodiment, the embossing pattern 11 has identical or equally sized embossments 12 or essentially identical or equally sized embossments 12 with a homogeneous distribution of embossments 12 of the same geometry or of essentially the same geometry.

Within the scope of the invention, the smallest distance d between two embossings 12 of the embossing pattern 11 is 0.6 to 3.0 mm. Smallest distance d between two embossings 12 means in particular the smallest distance d between two immediately adjacent embossings 12 of the embossing pattern 11, i.e. preferably the smallest distance d of one embossing 12 to the nearest embossing 12 of the embossing pattern 11. In addition, the smallest distance d refers to two Embossings 12 in particular to the smallest distance d between the embossing boundaries of two embossings 12, i.e. to the smallest distance between the two embossings 12 along the non-embossed surface of the nonwoven material 1 in between.

The thickness h of the nonwoven fabric 1 is expediently 0.15 to 0.75 mm. In the exemplary embodiment according to the figures, the thickness h of the nonwoven fabric 1 may be approximately 0.4 mm. Thickness h means the greatest thickness or total thickness of the nonwoven fabric 1 transversely, in particular perpendicular or essentially perpendicular to its flat extent in the non-embossed areas of the nonwoven fabric 1. This is particularly in the 4 to recognize.

Claims (23)

Method for producing a nonwoven fabric (1) with at least one nonwoven web (2) made of fibers, wherein fibers are produced with at least one fiber production device, in particular with at least one spinning beam (3), the fibers then being placed on at least one depositing device, in particular on a depositing screen belt (4), are deposited into the nonwoven web (2), the nonwoven web (2) or the nonwoven fabric (1) having at least one calender roll (5), in particular with at least one calender (6) or pair of calender rolls having the calender roll (5). (5, 7), is solidified and wherein the nonwoven fabric (1) is also with at least one hot fluid main solidification device, in particular with at least one hot air main solidification device (8), is solidified or main solidified. Procedure according to Claim 1 , wherein the nonwoven fabric (1) is detached from the storage device before solidification with the at least one calender roll (5) and / or before solidification or main solidification with the at least one hot fluid main solidification device. Procedure according to one of the Claims 1 or 2 , wherein the solidification of the nonwoven fabric (1) with the at least one calender roll (5), in particular with at least one calender (6) or pair of calender rolls (5, 7) having the calender roll (5), before or after the solidification or main solidification of the Nonwoven fabric (1) with the at least one hot fluid main consolidation device, in particular with the at least one hot air main consolidation device (8). Procedure according to one of the Claims 1 until 3 , wherein the nonwoven fabric (1) after being deposited on the depositing device and before solidification or main solidification, is initially connected to at least one, preferably the at least one fiber producing device or the at least one spinning beam (3) downstream, in particular immediately downstream, pre-solidification device, preferably with at least a hot fluid pre-solidification device, preferably with at least one hot air pre-solidification device (9), and wherein the at least one hot fluid pre-solidification device or hot air pre-solidification device (9) is particularly preferably designed as a hot air knife and / or as a hot air field. Procedure according to one of the Claims 1 until 4 , wherein the at least one hot fluid main solidification device or the at least one hot air main solidification device (8) is preferably designed as a hot air oven, particularly preferably as an Omega oven and / or as a multi-drum oven and / or as a single belt oven and / or as a double belt oven. Procedure according to one of the Claims 1 until 5 , wherein the residence time of the nonwoven fabric (1) in the hot fluid main consolidation device is 0.4 s to 25 s, preferably 1 s to 15 s and / or wherein the fluid velocity of the fluid of the hot fluid main consolidation device is 0.4 to 3 m / s, is preferably 0.5 to 2 m/s. Procedure according to one of the Claims 1 until 6 , wherein the surface temperature T1 of the at least one calender roll (5), in particular of the at least one calender (7) or pair of calender rolls (5, 7) having the calender roll (5), is higher, preferably by 0.5 ° C to 10 ° C , preferably 1 ° C to 5 ° C higher than the fluid temperature T2 of the at least one hot fluid main solidification device or lower than the fluid temperature T2 of the at least one hot fluid main solidification device or identical or substantially identical to the fluid temperature T2 of the at least one Hot fluid main solidification device is. Procedure according to one of the Claims 1 until 7 , wherein the fibers of the at least one nonwoven web (2) are produced or spun as continuous filaments (10), preferably as crimped continuous filaments (10), the continuous filaments (10) or the crimped continuous filaments (10) particularly preferably as multi-component filaments and are particularly preferably produced or spun as bicomponent filaments. Procedure according to Claim 8 , wherein the multicomponent filaments or bicomponent filaments have a first, preferably low-melting, component which consists or essentially consists of at least one thermoplastic, in particular of at least one polyolefin, preferably polyethylene and / or polypropylene and / or wherein the multicomponent filaments or Bicomponent filaments have a second or further, preferably higher melting, component which consists or essentially consists of at least one thermoplastic, in particular of at least one polyester and / or polypropylene. Procedure according to one of the Claims 8 or 9 , wherein the continuous filaments (10), preferably the crimped continuous filaments (10), are produced or produced as multicomponent filaments or bicomponent filaments with a side-by-side configuration and/or with a core-sheath configuration, in particular with an eccentric core-sheath configuration .are spun and the first component is preferably the sheath component and the second component is the core component. Procedure according to one of the Claims 9 or 10 , wherein the surface temperature T1 of the at least one calender roll (5), in particular of the at least one calender (7) or pair of calender rolls (5, 7) having the calender roll (5) and / or the fluid temperature T2 of the at least one hot fluid main solidification device with respect to the melting temperature Tm of the first, preferably low-melting, component, the multicomponent filaments or bicomponent filaments meets the following condition: (Tm-15 ° C) < T1 and / or T2 < (Tm + 15 ° C), preferably (Tm - 10 ° C ) < T1 and/or T2 < (Tm+10°C), preferably (Tm-8°C) <T1 and/or T2 <(Tm+8°C), particularly preferably (Tm-7°C) <T1 and/or T2 <(Tm+7°C), very particularly preferred (Tm-6°C) < T1 and/or T2 < (Tm+6°C), for example (Tm-5°C) < T1 and/or T2 < (Tm+5°C). Procedure according to one of the Claims 1 until 11 , wherein by means of the at least one calender roll (7) an embossed pattern (11) made up of a plurality of - preferably not interconnected - embossments (12) is introduced into the nonwoven fabric (1), the embossments (12) preferably each having an embossing surface (13 ) from 0.05 to 0.6 mm ² , preferably from 0.06 to 0.4 mm ² , preferably from 0.07 to 0.25 mm ² , particularly preferably from 0.08 to 0.15 mm ² and whole particularly preferably from 0.09 to 0.12 mm ² . Procedure according to Claim 12 , wherein the embossed pattern (11) is produced with the proviso that the smallest distance d between two embossments (12) of the embossed pattern (11) is 0.6 to 3.0 mm, preferably 0.8 to 2.5 mm, preferably 0 .9 to 2.0 mm, particularly preferably 0.95 to 1.8 mm and most preferably 1.0 to 1.5 mm. Procedure according to one of the Claims 12 or 13 , wherein the embossed pattern (11) is produced with the proviso that the proportion of the total embossed area of the embossed pattern (11) to the total surface of the nonwoven fabric (1) is 2 to 15%, preferably 2.5 to 12%, preferably 3 to 8%, particularly preferably 3.5 to 6% and very particularly preferably 3.8 to 5.2%. Procedure according to one of the Claims 1 until 14 , wherein a nonwoven fabric (1) with at least two nonwoven webs (2, 2 ') is produced from fibers, with first fibers being produced by at least one first fiber production device, in particular by at least one first spinning beam (3), and then on the storage device, in particular on the depositing screen belt (4), to form the non-woven web (2), second fibers being produced by at least one second fiber producing device, in particular by at least one second spinning beam (3'), and then on the first non-woven web (2) to form the second non-woven web (2') are deposited and the aggregate consisting of the at least two non-woven webs (2, 2') or the non-woven fabric (1) with at least one calender roll (5), in particular with at least one calender (6) having the calender roll (5). or calender roller pair (5, 7), and wherein the nonwoven fabric (1) is also solidified or main-solidified with at least one hot fluid main consolidation device, in particular with at least one hot air main consolidation device (8). Device for producing a nonwoven fabric (1) with at least one nonwoven web (2) made of fibers, in particular for carrying out a method according to one of Claims 1 until 15 , wherein the device (14) has at least one fiber producing device, in particular at least one spinning beam (3), and at least one depositing device, in particular at least one depositing sieve belt (4), for depositing the fibers into the nonwoven web (2), furthermore at least one calender roll ( 5), in particular a calender (6) or pair of calender rolls (5, 7) having the calender roll (5), is provided for solidifying the nonwoven fabric (1) and in addition at least one hot fluid main solidifying device, in particular at least one hot air main solidifying device ( 8) is present for the consolidation or main consolidation of the nonwoven fabric. Device according to Claim 16 , wherein the at least one calender roll (5), in particular the calender (6) having the calender roll (5) or the pair of calender rolls (5, 7) is arranged in front of or behind the at least one hot fluid main consolidation device in the conveying direction F of the nonwoven material (1). . Device according to one of the Claims 16 or 17 , wherein the at least one calender roll (5) has a complementary embossing pattern (15) made of embossing elements (16) for introducing an embossing pattern (11) made of a plurality of embossings (12) into the nonwoven fabric (1), the embossing elements (16) preferably each a pressing surface (17) of 0.05 to 0.6 mm ² , preferably of 0.06 to 0.4 mm ² , more preferably of 0.07 to 0.25 mm ² , particularly preferably of 0.08 to 0, 15 mm ² and very particularly preferably from 0.09 to 0.12 mm ² . Nonwoven fabric produced by a process according to one of Claims 1 until 15 and/or with a device according to one of the Claims 16 until 18 . non-woven fabric Claim 19 , wherein the nonwoven fabric (1) has an embossed pattern (11) made up of a plurality of - preferably not interconnected - embossments (12), the embossments (12) preferably each having an embossed surface (13) of 0.05 to 0.6 mm ² , preferably from 0.06 to 0.4 mm ² , more preferably from 0.07 to 0.25 mm ² , particularly preferably from 0.08 to 0.15 mm ² and very particularly preferably from 0.09 to 0, 12 mm ² and/or wherein the embossed surfaces (13) of the embossments (12) in the plan view preferably have at least one geometry selected from the group: “point-shaped or circular, elliptical “shaped, square, rectangular, diamond-shaped, polygonal, linear, wavy”. non-woven fabric Claim 20 , wherein the nonwoven fabric (1) has a basis weight of less than 200 g/m ² , in particular of less than 150 g/m ² , preferably of less than 100 g/m ² , preferably of less than 75 g/m ² , particularly preferred of less than 50 g/m ² and very particularly preferably of less than 30 g/m ² and/or wherein the nonwoven fabric (1) has a thickness h of 0.1 to 1.0 mm, preferably of 0.15 to 0 .8 mm, preferably from 0.2 to 0.65 mm, particularly preferably from 0.25 to 0.55 mm. Non-woven fabric according to one of the Claims 20 or 21 , wherein the nonwoven fabric (1) has an abrasion resistance of at least Class 2 according to Martindale, preferably of Class 1 according to Martindale and/or wherein the nonwoven fabric (1) has a maximum flexural rigidity with a cantilever of a maximum of 100 mm, preferably a maximum of 90 mm of a maximum of 80 mm, particularly preferably of a maximum of 70 mm and very particularly preferably of a maximum of 65 mm. Non-woven fabric according to one of the Claims 20 until 22 , wherein the nonwoven fabric (1) is designed as a nonwoven laminate made of at least two nonwoven webs (2, 2 ') or nonwoven layers.

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