Method and device for producing a nonwoven fabric

Abstract

The invention relates to a method for producing a nonwoven fabric comprising at least one nonwoven web composed of fibres. The fibres are produced by means of at least one fibre-producing device. Subsequently, the fibres are deposited on at least one depositing device in order to form the nonwoven web. The nonwoven web or nonwoven fabric is solidified with at least one calender roller, and the nonwoven fabric is also solidified or primarily solidified with at least one hot fluid primary solidification device.

Description

[0001] Method and device for producing a nonwoven fabric

[0002] Description:

[0003] The invention relates to a method for producing a nonwoven fabric comprising at least one nonwoven web of fibers, wherein fibers are produced using at least one fiber-producing device, in particular at least one spinning beam, and the fibers are subsequently deposited on at least one depositing device, in particular on a depositing screen belt, to form the nonwoven web. The invention also relates to an apparatus for producing a nonwoven fabric.

[0004] Methods and devices for producing nonwovens are generally known in practice in various embodiments. The fibers produced are usually deposited on a depositing device to form the nonwoven web and then pre-consolidated to ensure the transportability of the nonwoven web or nonwoven fabric and to ensure that the nonwoven web is not shifted or destroyed during transport through the device. For further consolidation or main consolidation, the nonwoven fabric is generally fed to a downstream device. Known downstream devices for the consolidation or main consolidation of nonwovens include calenders with at least one calender roll, in particular with at least one pair of calender rolls. Calender rolls with embossing elements are often used, which introduce an embossed pattern consisting of a plurality of embossings into the nonwoven fabric during the consolidation process.Nonwovens that have been treated with at least one calender are characterized by advantageous mechanical strength, but these nonwovens often have a low thickness or a low volume. Furthermore, the embossed patterns introduced into the nonwovens with a calender are advantageous or necessary with regard to the mechanical properties of the nonwovens, but are disadvantageous for aesthetic reasons, as the optical properties of the nonwoven are disadvantageously influenced. In practice, therefore, hot fluid bonding devices or hot air bonding devices such as hot air ovens are also known as alternatives to the bonding or main bonding of nonwovens. Nonwovens that are bonded or main bonded with such bonding devices are generally characterized by advantageous thickness orThey are characterized by voluminosity, but often have undesirable stiffness or are difficult to drape and sometimes have disadvantageously low abrasion resistance.

[0005] An acceptable compromise between sufficient mechanical strength, satisfactory thickness or bulk, low stiffness or satisfactory drapability, and adequate abrasion resistance could previously only be achieved by blending different fiber types in nonwovens. However, this is complex, and the corresponding processes are also limited in their flexibility.

[0006] 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 effectively and reliably avoided and with which, in particular, a nonwoven fabric can be produced which is characterized by advantageous mechanical properties, for example, by sufficient mechanical strength or surface resistance, by sufficient thickness or voluminosity, by low stiffness or satisfactory drapability, and preferably by improved abrasion resistance, wherein an optimal compromise between these nonwoven fabric properties is particularly desirable. Furthermore, 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, wherein fibers are produced with at least one fiber production device, in particular with at least one spinning beam, wherein the fibers are then deposited on at least one depositing device, in particular on a depositing screen belt, to form the nonwoven web, wherein the nonwoven web or the nonwoven fabric is consolidated with at least one calender roll, in particular with at least one calender or calender roll pair having the calender roll, and wherein the nonwoven fabric is additionally consolidated or main consolidated with at least one hot fluid main consolidating device, in particular with at least one hot air main consolidating device.

[0007] In the context of the invention, the nonwoven fabric comprising at least one nonwoven web made of fibers means, in particular, that the nonwoven fabric comprises at least one nonwoven web or nonwoven layer made of produced and deposited fibers. According to one embodiment, the nonwoven fabric may comprise only one nonwoven web or nonwoven layer, or it may comprise several nonwoven webs or nonwoven layers arranged one above the other, which are combined to form a nonwoven laminate.

[0008] The term consolidation or main consolidation in the context of the invention means in particular a consolidation of the nonwoven fabric that leads to a higher degree of consolidation of the nonwoven fabric than pre-consolidation. It is within the scope of the invention that with main consolidation, a lower or higher degree of consolidation of the nonwoven fabric is achieved than with consolidation, or that with main consolidation, a degree of consolidation of the nonwoven fabric that is identical or essentially identical to 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 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 orthe nonwoven laminate has at least one meltblown nonwoven web or meltblown nonwoven layer. It is further 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 from at least four, nonwoven webs or nonwoven layers. The individual nonwoven webs or nonwoven layers can each be laid down as spunbond nonwoven webs or nonwoven layers. In principle, however, the nonwoven laminate could also be produced with at least one meltblown nonwoven web or meltblown nonwoven layer. The spunbond nonwoven webs or spunbond nonwoven layers are preferably each laid down from continuous filaments or crimped continuous filaments. This is explained in more detail below.

[0009] In the context of the invention, the term "hot fluid" refers to a temperature-controlled or heated fluid. The hot fluid is preferably a temperature-controlled or heated gas, and particularly preferably hot air. In principle, however, the hot fluid can also be a temperature-controlled or heated liquid, for example, water.

[0010] A particularly preferred embodiment of the method according to the invention is characterized in that the nonwoven fabric is detached from the depositing device before consolidation with the at least one calender roll and / or before consolidation or main consolidation with the at least one hot fluid main consolidation device. Particularly preferably, both the consolidation with the at least one calender roll or with the at least one calender having the calender roll and the consolidation or main consolidation with the at least one hot fluid main consolidation device take place after the nonwoven fabric has been detached from the depositing device. For this purpose, the nonwoven fabric is expediently transferred to the calender roll or 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 consolidation orMain consolidation takes place with at least one hot air main consolidation device on or above the depositing screen belt and that preferably only subsequently is the nonwoven fabric detached from the depositing device.

[0011] Within the scope of the method according to the invention, it has proven particularly useful that the consolidation of the nonwoven fabric with the at least one calender roll, in particular with at least one calender or calender roll pair comprising the calender roll, takes place before or after the consolidation or main consolidation of the nonwoven fabric with the at least one hot fluid main consolidation device, in particular with the at least one hot air main consolidation device. Very particularly preferably, the nonwoven fabric, in particular after detachment from the deposition device, is first consolidated with the at least one calender roll, in particular with at least one calender or calender roll pair comprising the calender roll, and then consolidated or main consolidated with the at least one hot fluid main consolidation device, in particular with the at least one hot air main consolidation device.This sequence of solidification steps has proven particularly useful within the scope of the invention and for solving the technical problem.

[0012] It is recommended that, after being deposited on the depositing device and before consolidation or main consolidation, the nonwoven fabric is first pre-consolidated with at least one pre-consolidation device, preferably one arranged downstream of, in particular directly downstream of, the at least one fiber production device or the at least one spinning beam, preferably with at least one hot fluid pre-consolidation device, more preferably with at least one hot air pre-consolidation device. The pre-consolidation thus takes place in particular before consolidation with the at least one calender roll or with the at least one calender and before consolidation or main consolidation with the at least one hot fluid main consolidation device. The pre-consolidation step ensures, in particular, the transportability of the deposited nonwoven web orof the nonwoven fabric and, according to a preferred embodiment, also the detachability of the nonwoven fabric from the deposition device, as well as the functionally reliable transfer to one of the devices provided according to the invention for consolidating 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 the deposition of each nonwoven web, a pre-consolidation takes place with a pre-consolidation device or hot-fluid pre-consolidation device, which is expediently arranged downstream of the associated fiber production device or the associated spinning beam, in particular directly downstream.

[0013] It is within the scope of the method according to the invention that the at least one hot fluid pre-consolidation device or hot air pre-consolidation device is designed as a hot air knife and / or as a hot air field. In principle, however, the pre-consolidation device can also be at least one roller or one smooth roller, in particular a pair of rollers or 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 a preferred embodiment with several nonwoven webs or nonwoven layers, a hot air knife is preferably used as the pre-consolidation device for the uppermost or last laid nonwoven web or nonwoven layer, and for the remaining nonwoven webs or nonwoven layers, in particular a hot air knife and a hot air field are used as the pre-consolidation device.In the latter case, hot air dwell times of more than 0.1 s have proven particularly effective.

[0014] It has proven particularly useful within the scope of the invention that the at least one hot-fluid main consolidation device or the at least one hot-air main consolidation device is designed as a hot-air oven, particularly preferably as an omega oven and / or a multi-drum oven and / or a single-belt oven and / or a double-belt oven. Consolidation or main consolidation with the at least one hot-fluid main consolidation device is expediently carried out by applying at least one hot fluid to the nonwoven fabric on one or both sides in the at least one hot-fluid main consolidation device.

[0015] It has also proven particularly useful within the scope of the invention for the at least one hot-fluid main consolidation device or the at least one hot-air main consolidation device to be 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 a double-belt oven. According to one embodiment of the invention, consolidation or main consolidation with the at least one hot-fluid main consolidation device takes place by applying at least one hot fluid to one or both sides of the nonwoven fabric in the at least one hot-fluid main consolidation device and in particular before detachment from the deposition device, wherein the nonwoven fabric is preferably subsequently consolidated after detachment with the at least one calender roll, in particular with at least one calender or calender roll pair comprising the calender roll.It is also within the scope of the invention that at least two hot-fluid main consolidation devices are provided, wherein a first consolidation or main consolidation of the nonwoven fabric preferably takes place with a first hot-fluid main consolidation device before the nonwoven fabric is detached from the deposition device, and wherein a second or further consolidation or main consolidation preferably takes place with a second hot-fluid main consolidation device after the nonwoven fabric has been detached from the deposition device and particularly preferably after consolidation with the at least one calender roll, in particular with at least one calender or calender roll pair having the calender roll. In this exemplary embodiment, the at least one calender roll is thus preferably arranged between two hot-fluid main consolidation devices in the conveying direction F of the nonwoven fabric.

[0016] According to a particularly preferred embodiment of the method according to the invention, the residence time of the nonwoven fabric in the hot fluid main consolidation 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 consolidation device is 0.4 to 3 m / s, preferably 0.5 to 2 m / s.

[0017] 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 calender roll pair comprising the calender roll, is higher, preferably by 0.5°C to 10°C, more preferably by 1°C to 5°C higher, than the fluid temperature T2 of the at least one hot fluid main consolidation device, or is lower than the fluid temperature T2 of the at least one hot fluid main consolidation device, or is identical or substantially identical to the fluid temperature T2 of the at least one hot fluid main consolidation device. Within the scope of the invention, the at least one calender roll, in particular of the at least one calender or calender roll pair comprising the calender roll, is preferably a heated calender roll or a heated calender. Due to the temperature conditions of the surface temperature of the at least one calender roll orof the calender and the fluid temperature of the at least one hot fluid main consolidation device, a method can be provided - in particular in combination with the residence times and / or fluid velocities explained above - 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, simply and reliably.

[0018] 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 continuous filaments. Particularly preferably, the fibers of all nonwoven webs are produced as continuous filaments within the scope of the inventive method. In this case, "fibers" within the scope of the invention refers in particular to continuous filaments. Continuous filaments differ from short fibers due to their virtually continuous length, which have significantly shorter lengths of, for example, 1 mm to 60 mm.

[0019] 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 from at least one thermoplastic, preferably from 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 aforementioned thermoplastics. According to one embodiment, copolymers of the aforementioned thermoplastics are used.Conventional additives such as plasticizers, fillers, dyes, and the like can be added to the aforementioned thermoplastics. It is within the scope of the invention for the continuous filaments of the at least one nonwoven web or at least one nonwoven web of the nonwoven fabric to be produced as spunbond continuous filaments. It is also possible in principle for the continuous filaments of the at least one nonwoven web or at least one nonwoven web of the nonwoven fabric to be produced as meltblown continuous filaments.

[0020] 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, wherein the continuous filaments or the crimped continuous filaments are particularly preferably produced or spun as multicomponent filaments and very particularly preferably as bicomponent filaments.

[0021] In this context, it has proven particularly useful for the multi-component filaments or bi-component filaments to 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 of polyethylene and / or polypropylene, and / or for the multi-component filaments or bi-component filaments to 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. The term low-melting component, in particular first low-melting component, in the context of the invention means in particular a component of the multi-component filaments orBicomponent filaments are meant to have a lower melting point than a comparatively higher-melting component, in particular the second or further higher-melting component of the multicomponent filaments or bicomponent filaments. Within the scope 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.

[0022] Polyethylene terephthalate (PET) and / or polylactide (PLA) are particularly suitable as polyesters within the scope of the invention. According to one embodiment, copolymers of these plastics are used. When here or below the term “essentially consists” is stated with reference 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 is present to an extent of at least 95% by weight, preferably to an extent of at least 97% by weight and more preferably to an extent of at least 98% by weight. The remaining % by weight can in particular be formed from 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 multi-component filaments or the bi-component filaments is based on polyethylene and preferably consists of polyethylene oressentially made of polyethylene. According to a further preferred embodiment, the first, preferably low-melting, component of the multicomponent or bicomponent filaments is based on polypropylene and preferably consists of polypropylene or essentially of polypropylene. Instead of polypropylene or in addition to polypropylene, at least one polypropylene copolymer can also be used within the scope of the invention.

[0023] 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 based on at least one polyester and / or 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 or in addition to polypropylene, and preferably at least one polyester copolymer can be used instead of or in addition to the polyester. Suitable polyesters are particularly suitable as polyethylene terephthalate (PET) and / or polylactide (PLA), and a particularly suitable polyester copolymer is a PET copolymer (co-PET).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.

[0024] It is within the scope of the process according to the invention that the continuous filaments, preferably the crimped continuous filaments, are produced or spun 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, and wherein preferably the first, preferably low-melting, component is 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 possible within the scope of the invention for the core-sheath configuration to be centric.

[0025] If the continuous filaments or the crimped continuous filaments are produced or spun as multi-component filaments or bi-component filaments with an eccentric core-sheath configuration according to a preferred embodiment, it is within the scope of the invention that both the sheath of the filaments and the core of the filaments are circular in shape when viewed in the filament cross-section. According to a further preferred embodiment of the invention, the multi-component filaments or bi-component filaments are produced or spun as multi-component filaments or bi-component filaments with an eccentric core-sheath configuration, and the core of these filaments is circular in shape when viewed in the filament cross-section and has an arc-shaped circumferential section and a linear circumferential section with respect to its circumference, resulting in a D-shape of the core when viewed in the filament cross-section.the crimped continuous filaments are produced or spun in the context of the process according to the invention as multi-component filaments or bi-component filaments with at least one above-described first, preferably low-melting, component and at least one above-described second or further, preferably higher-melting, component, the proportion of the first, preferably low-melting, component of the multi-component filaments or bi-component filaments in the at least one nonwoven web of the nonwoven fabric is 10 to 90 wt.%, preferably 20 to 70 wt.%, more preferably 30 to 50 wt.% - based on the components of the multi-component filaments or bi-component filaments.

[0026] The design of the fibers of the nonwoven fabric as multi-component filaments or bi-component filaments, in particular with a first, preferably low-melting component and a second or further, preferably higher-melting component, and furthermore the preferred design of the multi-component filaments or bi-component 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 these components orConfigurations of the filaments allow the nonwoven fabric properties to be adjusted very flexibly and that, in particular in combination with the consolidation provided according to the invention with at least one 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 fabric properties can be achieved to solve the technical problem according to the invention.

[0027] 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 comprising the calender roll and / or the fluid temperature T2 of the at least one hot fluid main consolidation device with respect to the melting temperature Tm of the first, preferably low-melting, component of the multicomponent filaments or bicomponent filaments, fulfills 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 preferably (Tm-6°C) < T1 and / or T2 < (Tm+6°C), for example (Tm-5°C) < T1 and / or T2 < (Tm+5°C).Within the scope 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 scanning 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 above-mentioned condition. 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, lower than T2, or identical to T2.If the hot fluid main solidification device, in particular the hot air main solidification device according to a preferred embodiment, is a hot air oven, then the fluid temperature, moreover, 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.

[0028] According to a very preferred embodiment of the method according to the invention, an embossed pattern consisting of a plurality of - preferably unconnected - embossings is introduced into the nonwoven fabric by means of 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 calender roll pair is preferably a calender roll for introducing an embossed pattern consisting of a plurality of embossings into the nonwoven fabric. For this purpose, the calender roll preferably has a complementary embossed pattern consisting of embossed elements. This will be explained in more detail below. The other or further roll of the calender or calender roll pair is expediently a smooth roll with a smooth outer surface.Within the scope of the method according to the invention, the nonwoven fabric is thus preferably consolidated using a calender having at least one calender roll for introducing an embossed pattern consisting of a plurality of embossings into the nonwoven fabric, and more preferably at least one smooth roll. The embossed pattern is then 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 fabric on both sides of the nonwoven fabric, with the embossing depth being distributed differently across the two sides of the nonwoven fabric.It is within the scope of the invention that, when using a calender comprising at least one pair of calender rolls, wherein one of the calender rolls has embossing elements for introducing an embossed pattern consisting of a plurality of embossings into the nonwoven fabric and one calender roll is designed as a smooth roll, the two calender rolls have a different surface temperature for consolidating the nonwoven fabric. 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 refers in particular to the temperature of the calender roll with embossing elements.In the context of the invention, the term "embossing" refers in particular to a compacted area of ​​the nonwoven fabric where the nonwoven fabric has a particularly reduced thickness compared to its non-embossed areas and where the fibers of the nonwoven fabric are at least partially bonded or fused to one another, preferably by the action of pressure and / or temperature. According to a particularly preferred embodiment of the method according to the invention, the embossings each have an embossed area of ​​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 most 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 , most preferably less than 0.12 mm 2 , for example less than 0.1 mm 2 These embodiments are based on the finding that with an embossed pattern composed of embossings of this specific design and in particular with the relatively small embossed area, the optical perceptibility of the embossed pattern by the human eye can be at least significantly reduced, so that an impairment of the optical properties of the resulting nonwoven fabric can be almost completely avoided.

[0029] In the context of the invention, the term embossed pattern means in particular the pattern resulting from the multitude of embossed portions of the nonwoven fabric. The embossed pattern can be a regular and / or an irregular embossed pattern. It is preferred that the embossed pattern is a regular embossed pattern. The individual embossed portions are then preferably distributed at regular intervals, preferably at identical intervals, on the resulting nonwoven fabric. More preferably, the embossed surface of the individual embossed portions of the embossed pattern is the same size or essentially the same size. It has proven useful for the geometry of the embossed surfaces of the individual embossed portions to be identical or essentially identical. Very particularly preferably, the embossed pattern has embossed portions of the same size or the same size, or essentially the same size or the same size, with a homogeneous distribution of embossed portions of the same geometry or essentially the same geometry.In principle, however, it is also possible for the individual embossed portions of the embossed pattern to have different sizes and / or different geometries and / or for the embossed portions to be arranged in an irregular embossed pattern on the nonwoven fabric. In the context of the invention, the term "geometry of the embossed portions" refers in particular to the geometry of the embossed surfaces of the embossed portions in a top view.

[0030] In the context of the invention, the embossed surface of an embossing means in particular the embossed surface of an embossing, wherein, when determining the size of the embossed surface, any material overhang or material bead that may form during the pressing or embossing process and at least partially surrounds the embossing is in particular not part of the embossed surface of an embossing. In the case of an embossing or embossed surface with a point-shaped or circular geometry in plan view, the embossed surface of the embossing corresponds, for example, to the surface area of ​​the point-shaped or circular embossing, wherein any material overhang or material bead that may surround the embossing is not included in the embossed surface of the embossing.The fact that the embossings of the nonwoven fabric according to the invention each have an embossed area in the above-specified area 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 embossed area in the specified area. Particularly preferably, all embossings of the nonwoven fabric have an embossed area in the specified area. The embossed area of ​​an embossing can be determined, in the context of the invention, in particular by reflected light or transmitted light 2D microscopy, and / or by scanning electron microscopy (SEM) and / or by micro-computed tomography (pCT). In the corresponding image analysis, a geometry underlying the embossed area geometry or corresponding to the embossed area geometry or essentially corresponding to the embossed area geometry is preferably used as a basis and placed over the individual optically imaged embossed areas of the embossings for evaluation.

[0031] 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 embossings of the embossed pattern is in each case 0.6 to 3.0 mm, preferably 0.8 to 2.5 mm, more 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. Expediently, the smallest distance d between two embossings of the embossed pattern is in each case 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 embossed pattern means in particular the smallest distance d between two immediately adjacent embossings of the embossed pattern, i.e. preferably the smallest distance between an embossing and the nearest embossing of the embossed pattern.Furthermore, the smallest distance d between two embossed portions of the embossed pattern refers in particular to the smallest distance between the embossed portion boundaries of two embossed portions, i.e., to the smallest distance between the two embossed portions along the non-embossed area of ​​the nonwoven fabric lying between them. This embodiment is based, in particular, on the finding that this can further reduce the visual perceptibility of the embossed pattern composed of embossed portions. The above-described smallest distance between two embossed portions of the embossed pattern preferably refers to at least 95%, preferably to at least 97%, of all embossed portions of the nonwoven fabric. Particularly preferably, the described smallest distance between two embossed portions refers to all embossed portions of the nonwoven fabric.

[0032] 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 fabric is 2 to 15%, preferably 2.5 to 12%, more preferably 3 to 8%, particularly preferably 3.5 to 6%, and most 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%. By means of these above proportions of the total embossed area of ​​the embossed pattern to the total surface of the nonwoven fabric, the optical perceptibility of the embossed pattern from embossings can be further reduced.In this context, the total embossed area of ​​the embossed pattern refers in particular to the sum of all embossed areas of the embossed pattern. The total surface of the nonwoven fabric, within the scope of the invention, refers in particular to the entire nonwoven fabric surface, including the embossed and non-embossed areas.

[0033] It is within the scope of the process according to the invention that the calender line load of the calender roll or 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. Further 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 above-described total embossed area of ​​the embossed pattern relative to the total surface of the nonwoven fabric.

[0034] Within the scope of the method according to the invention, it is particularly preferred that a nonwoven fabric with at least two nonwoven webs of fibers is produced, wherein for this purpose first fibers are produced by at least one first fiber production device, in particular by at least one first spinning beam, and are then deposited on the depositing device, in particular on the depositing screen belt, to form the nonwoven web, wherein second fibers are produced by at least one second fiber production device, in particular by at least one second spinning beam, and are then deposited on the first nonwoven web to form the second nonwoven web, and wherein the aggregate comprising the at least two nonwoven webs or the nonwoven fabric is provided with at least one calender roll, in particular with at least one calender or spool having the calender roll.Calender roll pair, and wherein the nonwoven fabric is additionally consolidated or main consolidated with at least one hot fluid main consolidating device, in particular with at least one hot air main consolidating device. It has already been mentioned above that, within the scope 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 directly downstream, and that the laid down nonwoven webs are preferably first pre-consolidated with the respective pre-consolidation device before consolidation or main consolidation of the nonwoven fabric.

[0035] If, within the scope of the method according to the invention, a nonwoven fabric with at least two nonwoven webs of fibers is produced, 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 fabric 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 for the fibers of at least one nonwoven web or nonwoven layer assigned to an outer surface of the nonwoven fabric to be produced as crimped continuous filaments and / or as short fibers.This can, in particular, improve the softness of the nonwoven fabric and reduce its flexural rigidity.

[0036] 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 depositing device, in particular at least one depositing screen belt, for depositing the fibers to form the nonwoven web, wherein at least one calender roll, in particular a calender or calender roll pair comprising the calender roll, is provided for consolidating the nonwoven fabric and wherein at least one hot fluid main consolidating device, in particular at least one hot air main consolidating device is provided for consolidating or main consolidating the nonwoven fabric.

[0037] It is within the scope of the invention that the device has at least one pre-consolidation device, preferably arranged downstream of the at least one fiber production device or the at least one spinning beam, in particular arranged directly downstream of the at least one fiber production device or the at least one spinning beam, preferably at least one hot fluid pre-consolidation device, preferably at least one hot air pre-consolidation device, for pre-consolidating the nonwoven fabric, and wherein the at least one hot fluid pre-consolidation device or the at least one hot air pre-consolidation device is particularly preferably designed as a hot air knife and / or as a hot air field.

[0038] The deposition screen belt of the device according to the invention is expediently a continuously rotating deposition screen belt. It is within the scope of the invention that the at least one fiber production device or the at least one spinning beam is designed to produce a spunbond nonwoven web from continuous filaments, in particular from crimped continuous filaments. If the nonwoven fabric according to one embodiment of the invention is designed as a nonwoven laminate from 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 designed to produce spunbond nonwoven webs from continuous filaments, in particular from crimped continuous filaments. Very particularly preferably, the at least one fiber production device orThe at least one spinning beam, preferably all fiber-generating devices or all spinning beams of the device according to the invention, are configured to produce multicomponent filaments or bicomponent filaments. It is further within the scope of the invention that the device is designed to produce at least one nonwoven web from crimped continuous filaments. Preferably, at least one fiber-generating device or at least one spinning beam is configured to produce crimped continuous filaments. When using multiple 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 configured to produce crimped continuous filaments.

[0039] A very expedient embodiment of the invention is characterized in that at least one cooling device for cooling the fibers or filaments and at least one drawing device connected to the cooling device for drawing the fibers or filaments are provided for the fibers or continuous filaments spun with at least one fiber production device or at least one spinning beam. Advantageously, at least one diffuser is connected to the drawing device in the flow direction of the fibers or filaments. A highly recommended embodiment of the invention is characterized in that the unit comprising the cooling device and the drawing device is designed as a closed unit and that, apart from the supply of cooling air in the cooling device, no further air is supplied to this unit from the outside. Expediently, the fibers or filaments leaving the diffuser are deposited directly on the depositing device ordeposited on the sieve belt.

[0040] According to a preferred embodiment of the device according to the invention, the at least one calender roll, in particular the calender comprising the calender roll or the calender roll pair, is arranged upstream or downstream of the at least one hot-fluid main consolidation device in the conveying direction F of the nonwoven fabric. According to a preferred embodiment, the at least one hot-fluid main consolidation device is arranged upstream of the calender roll and in particular upstream of the calender comprising the calender roll in the conveying direction F of the nonwoven fabric. According to a very particularly preferred embodiment, the at least one hot-fluid main consolidation device is arranged downstream of the calender roll and in particular downstream of the calender comprising the calender roll in the conveying direction F of the nonwoven fabric.

[0041] 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 from 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 described above can be introduced into the nonwoven fabric. Advantageously, the calender or calender roll pair comprises, in addition to this calender roll, a second or further calender roll designed as a smooth roll with a smooth outer surface for introducing an embossing pattern of embossings into the nonwoven fabric.

[0042] 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 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 most preferably from 0.09 to 0.12 mm 2have. 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 embossed surface of the embossings. If the embossing elements of the calender roll are designed, for example, as cylindrical embossing elements for producing an embossed surface with a point-shaped or circular geometry in plan view, the pressing surface of the embossing elements corresponds in particular to the surface of the cylinder top side. If the embossing elements of the calender roll are designed, for example, as a truncated cone - i.e. with a flank angle - for producing an embossed surface with a point-shaped or circular geometry in plan view, the pressing surface of the embossing elements corresponds in particular to the top surface of the truncated cone.One embodiment of the invention utilizes multiple flank angles for the embossed elements, with the embossed elements preferably having smaller flank angles in the area intended for contact with the nonwoven fabric than further toward the base of the calender roll. The flank angle gradation can be gradual or continuous. Within the scope of the invention, the calender roll for introducing an embossed pattern of embossed elements into the nonwoven fabric is designed, with respect to its complementary embossed pattern and the arrangement and configuration of the embossed elements, in particular such that an embossed pattern with the parameters or properties described above can be realized in the nonwoven fabric.

[0043] It is within the scope of the invention that the embossed elements of the complementary embossed pattern of the at least one calender roll each have an embossed 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 refers in particular to the height difference between the pressing surface of an embossed element and the base of the calender roll. This embodiment is based on the finding that, during a calendering process with such a calender roll, compaction of the nonwoven fabric can be at least largely minimized.

[0044] To solve the technical problem, the invention further teaches a nonwoven fabric 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 consisting of a plurality of - preferably unconnected - embossments, wherein the embossments preferably each have an embossed area 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 most preferably from 0.09 to 0.12 mm 2and / or wherein the embossed surfaces of the embossings in plan 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 embossed surfaces or the embossings of the embossed pattern each have the same or essentially the same geometry. However, it is fundamentally also within the scope of the invention for the embossed pattern to have embossed surfaces or embossings of different geometries. A particularly preferred embodiment of the invention is characterized in that the embossed surfaces of the embossings or of all embossings are point-shaped or circular in plan view. In the context of the invention, geometry of the embossings means in particular the geometry of the embossed surfaces of the embossings in plan view.

[0045] A preferred embodiment of the nonwoven fabric according to the invention is characterized in that the aspect ratio of the embossed 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 embossed surface in this context means in particular the ratio of the greatest length or longitudinal extent of the embossed surface of an embossing to the greatest width or width extent of the embossed surface of the embossing and, for example, the ratio of the lengths of the axes of symmetry. In the case of a punctiform or circular geometry of the embossed surface of an embossing in plan view, the aspect ratio is, for example, equal to 1. In the case of an elliptical geometry of the embossed surface of an embossing in plan view, the aspect ratio corresponds, for example, to the ratio of the length of the major axis or major semi-axis to the length of the minor axis or minor semi-axis of the ellipse.For example, if the embossed surface of an embossing has a rectangular geometry in plan view, the aspect ratio corresponds to the ratio of the length of the rectangle to the width of the rectangle. For example, if the embossed surface of an embossing has a diamond-shaped geometry in plan view, the aspect ratio corresponds to the ratio of the length of the longer diagonal to the length of the shorter diagonal of the rhombus. For example, if the embossed surface of an embossing has a square geometry in plan view, the aspect ratio is 1. For curved lines, the aspect ratio of the enclosing rectangle preferably describes the aspect ratio of the embossed surface.

[0046] It is preferred that the nonwoven fabric has a basis weight of less than 200 g / m 2 , especially less than 150 g / m 2 , preferably less than 100 g / m 2 , preferably less than 75 g / m 2 , particularly preferably less than 50 g / m2 and most preferably less than 30 g / m 2 and / or that the nonwoven fabric has a thickness of 0.1 to 1.0 mm, preferably from 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 fabric is 10 g / m 2 up to 80 g / m 2 , preferably 15 g / m 2 up to 60 g / m 2 , preferably 15 g / m 2 up to 30 g / m 2It is also within the scope of the invention that the nonwoven fabric 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, more preferably of at least 0.6 mm, particularly preferably of at least 0.625 mm. Thickness h here means in particular the greatest thickness or total thickness of the nonwoven fabric transversely, in particular perpendicular or essentially perpendicular to its planar extension in the non-embossed regions of the nonwoven fabric. The thickness or total thickness h of the nonwoven fabric is measured according to the WRT 120.6(05)-Option A method.

[0047] 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 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, more preferably a maximum of 80 mm, more preferably a maximum of 70 mm and most preferably a maximum of 65 mm. This embodiment is based on the finding that the nonwoven fabric is then characterized by very satisfactory abrasion resistance and / or that the nonwoven fabric has an advantageously low flexural rigidity and, in particular, improved drapability compared to the known measures or nonwoven fabrics. This advantageously contributes to solving the technical problem and, in particular, to a compromise between optimal nonwoven fabric properties.The abrasion resistance of the nonwoven fabric is determined within the scope of the invention in particular using a Martindale abrasion tester according to the following test method:.

[0048] The test device used is the "SDL Atlas M235 Martindale Tester." The procedure for determining abrasion resistance is preferably based on WSP20.5(05), with the following deviations from WSP20.5(05) being provided: The surface (top / bottom) is tested separately; at least 10, preferably at least 20 tests are conducted per sample and surface, with the test pieces being taken evenly from the entire surface of the sample; the final result is the arithmetic mean. The test pieces must be taken from a representative position, for example, not just from the edge, as the test orthe deviations in the results should not be influenced by macroscopic deviations, such as those caused by poor process control, but only by typical (local) fluctuations; the tested sample is stretched over standard felt and mounted in the lower holder; the same nonwoven fabric is used as the moving upper friction surface, with the sides to be tested facing each other, this piece is attached together with the PU foam patch (e.g. from SDL Atlas); 9 kPa contact pressure; 32 cycles, i.e. two full rounds of the Lissajous figure; after each test, the pair (test specimen and upper friction surface) is replaced; the samples are rated from 1 to 5, with 1 being the best grade. If, for example, the mean value on the upper side is 1 and on the underside is 3, the sample is rated 1 overall. Only the changes in the nonwoven fabric are assessed; if the nonwoven fabric previously showed similar defects, these can be overlooked.This refers, for example, to fiber strands – groups or bundles of fibers on the surface. If a test specimen clearly exhibits these defects from the outset, the specimen should be excluded in case of doubt.

[0049] Grade 1: Virtually no change when viewed from above. The surface may be slightly loosened, but the filaments may only loosen and not form large or long clumps. Viewed from the side, the pile height of the loose filaments may not exceed 5 mm. Individual filaments may be pushed together into a small ball with a diameter of less than 2 mm.

[0050] Grade 2: In addition to the damage pattern above (Grade 1): Filaments are loosened and matted with neighboring filaments to form an elongated agglomerate. These filament groups are called "strands" or "strings" or "bundles." These strands are 5 to 40 mm long and connected to the substrate at least every 10 mm. A strand is max. 5 mm high (5 mm above the surface) and max. 2 mm wide.

[0051] Note 3: The "strands" above 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 their starting and ending points. It is possible to lift and move this strand, for example, with a needle.

[0052] Note 4: The strands are connected to neighboring strands to form a network, resembling a "spider web."

[0053] Note 5: The sample is further damaged, the first holes have appeared.

[0054] Within the scope of the invention, the flexural stiffness of the nonwoven fabric is determined in particular according to the method "WSP 90.1 (05) Standard Test Method for Stiffness of Nonwoven: Fabrics Using the Cantilever Test".

[0055] 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, most preferably at least 22.5 N / 5 cm. Machine direction (MD direction) within the scope of the invention refers in particular to the conveying direction F of the nonwoven fabric on the deposition device. The strength of the nonwoven fabric in the machine direction is determined within the scope of the invention in particular according to 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 test speed. According to a preferred embodiment of the invention, the nonwoven fabric is formed as a nonwoven laminate made of at least two nonwoven webs or nonwoven layers.

[0056] The invention is based on the finding that the process according to the invention can provide a nonwoven fabric characterized by an optimal compromise between advantageous mechanical properties, sufficient thickness or voluminosity, low stiffness or good drapability, and advantageous abrasion resistance. The inventive combination of consolidation with at least one calender roll, in particular with at least one calender or calender roll pair comprising the calender roll, and with at least one hot-fluid main consolidation device, allows an optimal compromise between these properties to be achieved. It should be emphasized that these nonwoven properties can be achieved very reliably within the scope of the process according to the invention and nevertheless with relatively simple measures. The process according to the invention is also characterized by optimal flexibility.According to a preferred embodiment, the nonwoven fabric properties can be further optimized by the temperature relationships between the calender roll or calender and the hot-fluid main bonding device, as well as by the components of the fibers or filaments and by the configuration of the fibers or filaments. If, according to a preferred embodiment, an embossed pattern consisting of a plurality of embossings, and according to a particularly preferred embodiment, an embossed pattern consisting of a plurality 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 be almost completely avoided, while the nonwoven fabric nevertheless exhibits the advantageous mechanical properties resulting from such a calendering or embossing process.In summary, it can be stated that an optimal compromise between the nonwoven properties explained above can be achieved within the scope of the invention. Due to the flexibility of the process, for example with regard to the temperatures used for the bonding steps or with regard to the design of the fibers or filaments, the nonwoven properties can be further optimized according to the preferred embodiments of the process according to the invention.

[0057] The invention is explained in more detail below using exemplary embodiments:

[0058] In the following three examples, only the consolidation or main consolidation of the nonwovens differs, whereby the following parameters and designs apply to all three examples (Examples 1 to 3):

[0059] It is a spunbond nonwoven fabric made of two spunbond nonwoven webs or nonwoven layers, which were spun together using a first spinneret and a second spinneret. The basis weight of the resulting nonwoven fabric was 20 g / m² each. 2The laydown screen belt speed was 315 m / min. The fibers were produced or laid down as crimped continuous filaments in the form of bicomponent filaments, with the filaments of the first spin beam having an eccentric core-sheath configuration with a D-shaped core, and the filaments of the second spin beam having a side-by-side configuration. Polyethylene (DOW Aspun 6850 + 2 wt.% white color additive) was used as the first component for the filaments of the first spin beam. Polypropylene (Exxon PP3155 + 5 wt.% Borealis HL712FB + 1 wt.% lubricant additive) was used as the second component for the filaments of the second spin beam. The mass ratio of the first component to the second component was 50:50. Polyethylene (DOW Aspun 6834 + 2 wt.% white color additive) was used as the first component for the filaments of the second spinning beam.Polypropylene (Exxon PP3155 + 1 wt.% Borealis HL712FB + 1 wt.% lubricant additive) was used as the second component for the filaments of the second spinning beam. The mass ratio of the first component to the second component was 40:60. The throughput for the first beam was 145 kg / h / m² and for the second beam 180 kg / h / m².

[0060] After the first beam, pre-consolidation was carried out using 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-consolidation with a hot air knife (625 m 3 / h / m; 145 °C, 90 mm overall length) and consolidation or main consolidation with a hot air field with three different consecutive temperature zones (length of each temperature zone 1200 mm each), which were operated at different temperatures in the various embodiments, as explained below. Subsequently, consolidation took place with a calender, where indicated. 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 denier.

[0061] For the consolidation or main consolidation of the nonwovens of the exemplary embodiments (Examples 1 to 3), the following common conditions and specifications 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 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 spacing of the embossing elements, determined analogously 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 bonding device in the form of an omega oven with a diameter of 1414 mm and an active, flow-through length of 3500 mm (air velocity: 0.8 m / s) was arranged downstream of the calender in the conveying direction F of the nonwoven fabric. The cantilever and Martindale values ​​given below were measured as described above; "top" in the Martindale data refers to the side assigned to the calender roll with embossing elements, and "bottom" to the side assigned to the deposition screen belt.

[0062] Example 1 :

[0063] Bonding or main bonding with the hot air field after the second spinning beam with three different consecutive 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; calender line load: 30 N / mm; omega oven temperature: 80°C.

[0064] The result was 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 abrasion resistance of Class 1 (top) and Class 1 (bottom) according to Martindale. The result is a product characterized by very favorable abrasion resistance, a very advantageously low cantilever value, sufficient strength, and satisfactory thickness. Example 2:

[0065] Bonding or main bonding with the hot air field after the second spinning beam with three different consecutive 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; calender line load: 30 N / mm; omega oven temperature: 128°C.

[0066] The result was a nonwoven fabric with a strength in the machine direction (MD) 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) and Class 1 (bottom) according to Martindale. The result is a product characterized by very favorable abrasion resistance, a favorable low cantilever value, very favorable strength, and sufficient thickness.

[0067] Example 3 (state of the art or not according to the invention):

[0068] Bonding or main bonding with the hot air field after the second spinning beam with three different consecutive temperature zones: 120°C / 130°C / 130°C; Calender: Open, i.e. no nonwoven contact or bonding with the calender; Omega oven temperature: 138°C; thus no combined bonding with the calender.

[0069] The result was a nonwoven fabric with a strength in the machine direction (MD direction) of 21.3 N / 5 cm, a thickness of 0.53 mm, and a cantilever of 105 mm, as well as an abrasion resistance of Class 2.5 (top) and Class 1 (bottom) according to Martindale. The result is a product characterized, in particular, by poor abrasion resistance on one side of the nonwoven fabric, a poor cantilever value, sufficient strength, and advantageous thickness.

[0070] The invention is explained in more detail below with reference to a drawing that represents only one exemplary embodiment. The drawing shows a schematic representation:

[0071] Fig. 1 a vertical section through a device according to the invention

[0072] Fig. 2 is a vertical section through a part of the device according to Fig. 1

[0073] Fig. 3 a nonwoven fabric according to the invention in plan view

[0074] Fig. 4 shows a cross section along AA according to Fig. 1 .

[0075] Fig. 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 continuous filaments 10. The device preferably has, and in the exemplary embodiment, two spinning beams 3, 3', which are preferably and in the exemplary embodiment each configured to produce a spunbond nonwoven web 2, 2' made of crimped continuous filaments 10 in the form of bicomponent filaments. Furthermore, according to a preferred embodiment, there is an endlessly circulating depositing screen belt 4 for depositing the continuous filaments 10 to form the nonwoven web 2, 2'. The device 14 preferably has, and in the exemplary embodiment, a calender roller 5 for introducing an embossed pattern 11 (Figures 3 and 4) made up of a plurality of unconnected embossments 12 into the nonwoven fabric 1.This calender roll 5 is preferably and in the exemplary embodiment part of a calender 6 comprising 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 comprising embossing elements 16, which preferably each have a pressing surface 17 of 0.05 to 0.6 mm. 2 Pressing surface 17 refers in particular to the surface of the embossing elements 16 of the calender roll 5 intended for producing an embossed surface 13 of the embossings 12 of the nonwoven fabric 1. Preferably, and in the exemplary embodiment according to Fig. 1, the embossing elements 16 of the calender roll 5 are frustoconical, and the pressing surface 17 corresponds to the top surface of the frustum. 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.

[0076] According to a particularly preferred embodiment and in the exemplary embodiment according to Fig. 1, the device 14 has a hot-air main consolidation device 8, which is preferably arranged in the conveying direction F of the nonwoven fabric behind the calender roll 5 or behind the calender 6. Preferably, and in the exemplary embodiment, the hot-air main consolidation device 8 is designed as a hot-air oven. Expediently, and in the exemplary embodiment, the device 14 also has two pre-consolidation devices in the form of hot-air pre-consolidation devices 9, 9'. The hot-air

[0077] Pre-consolidation devices 9, 9' are preferably and in

[0078] In the exemplary embodiment, the hot-air pre-consolidation devices 9, 9' are arranged in the conveying direction F of the nonwoven fabric 1 upstream of the calender roll 5 and upstream of the calender 6, respectively. Preferably, and in the exemplary embodiment according to Fig. 1, the hot-air pre-consolidation devices 9, 9' are each arranged directly downstream of a spinning beam 3, 3' for pre-consolidating the laid nonwoven web 2, 2'. A first hot-air pre-consolidation device 9 is preferably arranged directly downstream of a first spinning beam 3 in the conveying direction F of the nonwoven fabric 1, and this is followed by a second spinning beam 3', which is immediately downstream of the second hot-air pre-consolidation device 9'. The hot-air pre-consolidation devices 9, 9' are preferably configured as hot-air knives and / or as a hot-air field.

[0079] Within the scope of the method according to the invention and in the exemplary embodiment according to Fig. 1, a nonwoven web 2 made of crimped continuous filaments 10 is first produced by the first spinning beam 3 and deposited on the deposition screen belt 4. The nonwoven web 2 is then preferably pre-consolidated, in the exemplary embodiment, by means of the hot-air pre-consolidation device 9. Thereafter, a second nonwoven web 2' made of crimped continuous filaments 10 is expediently produced by the second spinning beam 3' and deposited on the first nonwoven web 2. The second nonwoven web 2' or the aggregate made up of the first nonwoven web 2 and the second nonwoven web 2' is recommended to be pre-consolidated using the second hot-air pre-consolidation device 9' and subsequently preferably detached from the deposition screen belt 4 and fed to the calender 6 having the calender roller 5.By means of the calender roller 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 consolidated in the process. Subsequently, the consolidation or main consolidation of the nonwoven fabric 1 preferably takes place by means of the at least one hot-air main consolidation device 8.

[0080] Fig. 2 shows the basic structure of a part of the device 14 according to the invention for producing a nonwoven web 2 using the spunbond process, comprising a spinneret or spinning beam 3 for spinning the continuous filaments 10 for the spunbond nonwoven web 2 from continuous filaments 10. The continuous filaments 10 spun by the spinneret or spinning beam 3 are introduced into a cooling device 18 having 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.

[0081] Recommended and in the exemplary embodiment, a drawing device 22 for drawing the continuous filaments 10 is arranged downstream of the cooling device 18 in the filament flow direction. Expediently and in the exemplary embodiment, the drawing device 22 has an intermediate channel 23 that connects the cooling device 18 to a drawing shaft 24 of the drawing device 22. Preferably, and in the exemplary embodiment, the assembly comprising the cooling device 18, the intermediate channel 23, and the drawing shaft 24 is designed as a closed assembly, and apart from the supply of cooling air in the cooling device 18, no further air is supplied from the outside to this assembly.

[0082] Conveniently, and in the exemplary embodiment, a diffuser 25, through which the continuous filaments 10 are guided, adjoins the drawing device 22 in the filament flow direction. After passing through the diffuser 25, the continuous filaments 10 are preferably deposited, in the exemplary embodiment, on a depositing device designed as a depositing screen belt 4. The depositing screen belt 4 is preferred and, in the exemplary embodiment, is designed as an endlessly circulating depositing screen belt 4. It is within the scope of the invention for the depositing screen belt 4 to be permeable to air, so that suction of process air from below through the depositing screen belt 4 is possible.

[0083] Figures 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 continuous filaments 10 and is designed in particular as a nonwoven laminate. The continuous filaments 10 may preferably, and in the exemplary embodiment, be crimped continuous filaments 10. 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 continuous filaments 10. The crimped continuous filaments 10 may, in the exemplary embodiment, be bicomponent filaments with an eccentric core-sheath configuration, wherein the sheath of the continuous filaments 10 preferably consists of, or substantially consists of, polyethylene, and wherein the core of the continuous filaments 10 consists of, or substantially consists of, at least one polyester and / or polypropylene.

[0084] Figures 3 and 4 also show that the nonwoven fabric 1 has an embossed pattern 11, wherein the embossed pattern 11 consists of a plurality of unconnected embossed portions 12. The embossed pattern 11 is preferably, and in the exemplary embodiment, a regular embossed pattern 11, the individual embossed portions 12 of which are preferably, and in the exemplary embodiment, distributed at regular intervals on the nonwoven fabric 1.

[0085] 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. Embossing surface 13 of an embossing 12 means, in the context of the invention and in the exemplary embodiment, in particular the embossed surface of an embossing 12, wherein when determining the size of the embossing surface 13, the material projection or material bead that may form during the pressing or embossing process and at least partially encloses the embossing 12 is not part of the embossing surface 13 of an embossing 12. This can be seen in particular in Fig. 4 in a hatched representation. More preferably, and in the exemplary embodiment, the embossing surface 13 of the individual embossings 12 of the embossed 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 embossings 12 have a punctiform or circular geometry in plan view. Very particularly preferably, and in the exemplary embodiment, the embossed pattern 11 has embossings 12 of the same or the same size or essentially the same orequally sized embossings 12 with a homogeneous distribution of embossings 12 of the same geometry or of essentially the same geometry.

[0086] Within the scope of the invention, the smallest distance d between two embossed portions 12 of the embossed pattern 11 is 0.6 to 3.0 mm each. The smallest distance d between two embossed portions 12 refers in particular to the smallest distance d between two immediately adjacent embossed portions 12 of the embossed pattern 11, i.e., preferably, the smallest distance d between one embossed portion 12 and the nearest embossed portion 12 of the embossed pattern 11. Furthermore, the smallest distance d between two embossed portions 12 refers in particular to the smallest distance d between the embossed portion boundaries of two embossed portions 12, i.e., to the smallest distance between the two embossed portions 12 along the non-embossed surface of the nonwoven fabric 1 located therebetween.

[0087] The thickness h of the nonwoven fabric 1 is expediently between 0.15 and 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 refers to the greatest thickness or total thickness of the nonwoven fabric 1 transversely, in particular perpendicularly or essentially perpendicularly to its planar extension in the non-embossed areas of the nonwoven fabric 1. This can be seen particularly in Fig. 4.

Claims

1. A method for producing a nonwoven fabric (1) with at least one web (2) made of fibers, wherein fibers are produced with at least one fiber generation device, in particular with at least one spinning beam (3), wherein the fibers are subsequently laid down on at least one depositing device, in particular on a depositing screen belt (4), to form the nonwoven web (2), wherein the nonwoven web (2) or the nonwoven fabric (1) is consolidated with at least one calender roll (5), in particular with at least one calender (6) or calender roll pair (5, 7) comprising the calender roll (5), and wherein the nonwoven fabric (1) is further consolidated or consolidated with at least one hot fluid main consolidation device, in particular with at least one hot air main consolidation device (8).

2. Method according to claim 1, wherein the nonwoven fabric (1) is detached from the depositing device before consolidation with the at least one calender roll (5) and / or before consolidation or main consolidation with the at least one hot fluid main consolidation device.

3. Method according to one of claims 1 or 2, wherein the consolidation of the nonwoven fabric (1 ) with the at least one calender roll (5), in particular with at least one calender (6) or calender roll pair (5, 7) comprising the calender roll (5), takes place before or after the consolidation or main consolidation 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).

4. Method according to one of claims 1 to 3, wherein the nonwoven fabric (1 ) after being placed on the depositing device and before consolidation or main consolidation is first coated with at least one, preferably the at least a fiber generation device or the at least one spinning beam (3) downstream, in particular immediately downstream, pre-solidification device, preferably with at least one 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.

5. Method according to one of claims 1 to 4, wherein the at least one hot fluid main consolidation device or the at least one hot air main consolidation device (8) is preferably designed as a hot air furnace, particularly preferably as an omega furnace and / or as a multi-drum furnace and / or as a single-belt furnace and / or as a double-belt furnace.

6. Method according to any one of claims 1 to 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 in the hot fluid main consolidation device is 0.4 to 3 m / s, preferably 0.5 to 2 m / s.

7. A method according to any one of claims 1 to 6, wherein the surface temperature T1 of the at least one calender roll (5), in particular of the at least one calender (7) or calender roll pair (5, 7) comprising the calender roll (5), is higher, preferably by 0.5°C to 10°C, more preferably by 1°C to 5°C, than the fluid temperature T2 of the at least one hot fluid main consolidation device, or is lower than the fluid temperature T2 of the at least one hot fluid main consolidation device, or is identical or substantially identical to the fluid temperature T2 of at least one hot fluid The main solidification device is.

8. Method according to any one of claims 1 to 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), wherein the continuous filaments (10) or the crimped continuous filaments (10) are particularly preferably produced or spun as multi-component filaments and most preferably as bi-component filaments.

9. Method according to claim 8, wherein the multi-component filaments or bi-component filaments comprise a first, preferably low-melting, component consisting of at least one thermoplastic material, in particular at least one polyolefin, preferably polyethylene and / or polypropylene, or consisting substantially of such material, and / or wherein the multi-component filaments or bi-component filaments comprise a second or further, preferably higher-melting, component consisting of at least one thermoplastic material, in particular at least one polyester and / or polypropylene, or consisting substantially of such material.

10. Method according to one of claims 8 or 9, wherein the continuous filaments (10), preferably the crimped continuous filaments (10), are produced or spun as multi-component filaments or bi-component filaments with side-by-side configuration and / or with Kem sheath configuration, in particular with eccentric Kem sheath configuration, and wherein preferably the first component is the sheath component and the second component is the core component.

11. A method according to claim 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 calender roll pair (5, 7) comprising the calender roll (5), and / or the fluid temperature T2 of the at least one hot fluid main consolidation device, with respect to the melting temperature Tm of the first, preferably low-melting, component, the multi-component filaments or bi-component filaments, satisfies the following condition: (Tm-15°C) < T1 and / or T2 < (Tm+15°C), preferably (Tm-10°C) < T1 and / or T2 < (Tm+10°C), more preferably (Tm-8°C) < T1 and / or T2 < (Tm+8°C), particularly preferably (Tm-7°C) < T1 and / or T2 < (Tm+7°C), most preferably (Tm-6°C) < T1 and / or T2 < (Tm+6°C), for example (Tm-5°C) < T1 and / or T2 < (Tm+5°C).

12. Method according to any one of claims 1 to 11, wherein an embossing pattern (11) consisting of a plurality of - preferably not interconnected - embossings (12) is introduced into the nonwoven fabric (1) by means of the at least one calender roll (7), wherein the embossings (12) preferably each have an embossing area (13) of 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 especially preferably from 0.09 to 0.12 mm 2 exhibit.

13. Method according to claim 12, wherein the embossing pattern (11 ) is produced with the stipulation that the smallest distance d between two embossings (12) of the embossing pattern (11 ) is 0.6 to 3.0 mm, preferably 0.8 to 2.5 mm, more preferably 0.9 to 2.0 mm, more preferably 0.95 to 1.8 mm and most preferably 1.0 to 1.5 mm.

14. Method according to one of claims 12 or 13, wherein the embossing pattern (11) is produced with the proviso that the proportion of the total embossing area of ​​the The embossing pattern (11) on 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 most particularly preferably 3.8 to 5.2%.

15. A method according to any one of claims 1 to 14, wherein a nonwoven fabric (1) with at least two webs (2, 2') is produced from fibers, wherein for this purpose first fibers are produced by at least one first fiber generation device, in particular by at least one first spinning beam (3) and are subsequently laid down on the lay-up device, in particular on the lay-up screen belt (4), to form the nonwoven web (2), wherein second fibers are produced by at least one second fiber generation device, in particular by at least one second spinning beam (3'), and are subsequently laid down on the first web (2) to form the second web (2'), and wherein the assembly consisting of the at least two webs (2, 2') or the nonwoven fabric (1) is combined with at least one calender roll (5), in particular with at least one calender (6) comprising the calender roll (5).calender roll pair (5, 7), is consolidated and wherein the nonwoven fabric (1 ) is also consolidated or main consolidated with at least one hot fluid main consolidation device, in particular with at least one hot air main consolidation device (8).

16. Device for producing a nonwoven fabric (1) with at least one web (2) of fibers, in particular for carrying out a method according to any one of claims 1 to 15, wherein the device (14) has at least one fiber generation device, in particular at least one spinning beam (3), and at least one depositing device, in particular at least one depositing screen belt (4), for depositing the fibers to form the web (2), wherein furthermore at least one calender roll (5), in particular a calender (6) or a pair of calender rolls (5, 7) comprising the calender roll (5), is provided for consolidating the nonwoven fabric (1), and wherein at least a hot fluid main consolidation device, in particular at least one hot air main consolidation device (8) for consolidation or main consolidation of the nonwoven fabric is available.

17. Device according to claim 16, wherein the at least one calender roll (5), in particular the calender (6) comprising the calender roll (5) or the pair of calender rolls (5, 7) is arranged in the conveying direction F of the nonwoven fabric (1) in front of or behind the at least one hot fluid main consolidation device.

18. Device according to one of claims 16 or 17, wherein the at least one calender roll (5) has a complementary embossing pattern (15) of embossing elements (16) for introducing an embossing pattern (11) from a plurality of embossings (12) into the nonwoven fabric (1), wherein the embossing elements (16) preferably each have a pressure surface (17) of 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 especially preferably from 0.09 to 0.12 mm 2 exhibit.

19. Nonwoven fabric produced according to a method according to any one of claims 1 to 15 and / or with a device according to any one of claims 16 to 18.

20. Nonwoven fabric according to claim 19, wherein the nonwoven fabric (1 ) has an embossing pattern (11 ) consisting of a plurality of - preferably not interconnected - embossings (12), wherein the embossings (12) preferably each have an embossing area (13) of 0.05 to 0.6 mm² 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 especially preferably from 0.09 to 0.12 mm 2 exhibit and / or wherein the embossed surfaces (13) of the embossings (12) in the top view preferably have at least one geometry selected from the group: "point-shaped or exhibit circular, elliptical, square, rectangular, diamond-shaped, polygonal, linear, wavy shapes.

21. Nonwoven fabric according to claim 20, wherein the nonwoven fabric (1) has a basis weight of less than 200 g / m² 2 , especially those of less than 150 g / m² 2 , preferably of less than 100 g / m² 2 , preferably less than 75 g / m² 2 , particularly preferably less than 50 g / m² 2 and especially preferably less than 30 g / m² 2 having 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 of 0.2 to 0.65 mm, particularly preferably of 0.25 to 0.55 mm.

22. Nonwoven fabric according to one of claims 20 or 21, wherein the nonwoven fabric (1) has an abrasion resistance of at least class 2 according to Martindale, preferably class 1 according to Martindale and / or wherein the nonwoven fabric (1) has a maximum flexural stiffness with a cantilever of at most 100 mm, preferably of at most 90 mm, preferably of at most 80 mm, particularly preferably of at most 70 mm and most particularly preferably of at most 65 mm.

23. Nonwoven fabric according to one of claims 20 to 22, wherein the nonwoven fabric (1 ) is formed as a nonwoven laminate from at least two nonwoven webs (2, 2') or nonwoven layers.

Images