Nonwoven fabric comprising filament layers

Abstract

Nonwoven fabric comprising a plurality of filaments layers, wherein said fabric comprises: - a first layer (A) forming an outer surface of said nonwoven fabric and comprising continuous multicomponent filaments comprising a component forming at least 20% of the surface of said filaments and being bonded within said first layer (A) and said component having a melting point at least 5°C lower than the melting point of the other components of the filaments of said first layer (A); and - a second layer (B) comprising continuous multicomponent filaments comprising a component forming at least 20% of the surface of said filaments and being bonded within said second layer (B) and said component having a melting point at least 5°C lower than the melting point of the other components of the filaments of said second layer (B), - wherein the bulk density of said fabric is lower than 60 kg / m 3 .

Description

Invention Field

[0001] This invention relates to nonwoven fabrics comprising layers of filaments. Background Technology

[0002] Nonwoven fabrics used in various fields must meet a variety of requirements based on their intended use. For example, key properties in areas such as disposable hygiene products, disposable cleaning products, and medical applications include softness, high bulkiness, and good resilience.

[0003] Combed materials are being and have been used in many such applications. However, producing nonwoven fabrics from combed fibers is complex, and fiber bonding within such nonwovens results in a significant reduction in bulk and softness, or in poorly bonded fibers and poor nonwoven quality, namely poor abrasion resistance.

[0004] Air-through bonding spinning technology is a viable solution for industrial requirements, primarily because the longer the fiber length overcomes some of the drawbacks of carded materials. Different methods are known in industry.

[0005] For example, the desired bulkiness and softness can be achieved, as disclosed in patent application WO2018059610, which describes the use of crimped filaments with a so-called crimpable cross section (e.g., eccentric core / sheath), or as disclosed in patent application WO2020103964 for PF Nonwovens, which describes the use of filaments with a non-crewable cross section (e.g., concentric core-sheath).

[0006] Nonwovens with good abrasion resistance as indicated by the Martindale abrasion test are described, for example, in WO2020112705.

[0007] WO2020107421 discloses an air-through bonding method for nonwoven fabrics, the purpose of which is to produce soft and fluffy fabrics. A web of continuous fibers is guided between a porous rotating member and a porous belt, while heated air flows through the web first from one side and then from the other. However, the description of this method is very vague and does not provide any data on the resulting product.

[0008] Ideal fabrics for industrial use are nonwovens that meet two requirements: softness-bulkness (good compressibility, drape, flexibility, non-stiffness, pleasant touch, etc.) and 3D stability (abrasion resistance, pilling resistance, etc.). Clearly, softness and 3D stability are not simple values ​​that can be easily measured, quantified, and compared; rather, they present complex characteristics that encompass a wide range of fabric properties and, in fact, a variety of fabrics under this single term. Many patents or applications claim protection for fabrics possessing softness, bulkiness (high thickness with low basis weight), and some degree of durability. Those skilled in the art will readily recognize that many of these patents or applications interpret the terms "softness" or "durability" very differently. For example, the aforementioned application WO2020103964 interprets softness as "softness-bulkness" and defines fabric softness based on a specific coefficient. Conversely, the aforementioned WO2020112705 defines softness based on a compression resilience test. Even if both fabrics are defined as soft, their behavior and the end-user's experience can be significantly different, and comparing them to each other is not easy.

[0009] The purpose of this invention is to provide a nonwoven fabric that is soft and fluffy, and does not pill during use. Summary of the Invention

[0010] This objective is achieved through a nonwoven fabric, specifically a nonwoven fabric comprising multiple filament layers as defined in claim 1, wherein the fabric comprises

[0011] - A first layer (A), the first layer (A) forming a first outer surface of the nonwoven fabric and comprising a continuous multicomponent filament containing components, the components

[0012] - Extending longitudinally along the filament,

[0013] - At least 20% of the surface forming the filament

[0014] - Filament-to-filament bonding is formed within the first layer (A), and

[0015] -Having a melting point at least 5°C lower than the melting point of the other components of the filament in the first layer (A), and

[0016] - Second layer (B), the second layer (B) comprising a continuous multi-component filament containing components, said components

[0017] - Extending longitudinally along the filament,

[0018] - At least 20% of the surface forming the filament

[0019] - Filament-to-filament bonding is formed within the second layer (B), and

[0020] -Having a melting point at least 5°C lower than the melting point of the other components of the filament in the second layer (B), and

[0021] -The loose density of the fabric is less than 60 kg / m³. 3 .

[0022] Other embodiments of the invention are defined in the dependent claims.

[0023] definition

[0024] The term "filament" is generally defined herein as an unended filament, while the term "short fiber" refers to fibers cut to a defined length. The terms "fiber" and "filament" are used herein to give the same meaning. The term "short fiber" is used specifically in cases where the fiber is cut.

[0025] The term "filament bonding" refers to all possible interactions between a single filament or individual sections of a filament, including adhesive, partially adhesive, or non-adhesive contact, crossing, interconnection, parallel contact, etc. Filament bonding can form a bond between filaments, but it can also exist where two independent filaments are in contact with each other without any restrictions on their relative movement.

[0026] The term "bonding between filaments" or "bonding point" refers to the bonding that typically connects two filaments at the points where they intersect, contact, or are adjacent to each other. Bonding points / bonding can connect more than two filaments or connect two parts of the same filament. Therefore, the term "bonding point" here refers to the interconnection of two or more fibers / filaments at the point of contact through their components exhibiting lower melting points. At the bonding point, the forming component of the filament with the higher melting point is generally less affected than the forming component of the filament with the lower melting point; that is, the sheath melts slightly while the core remains essentially unchanged. Conversely, the term "bonding indentation" refers to the surface on which a boss on a calender roll acts. A bonding indentation has a defined area given by the dimensions of the boss on the bonding roll and is generally thinner than adjacent areas. During the bonding process, the area of ​​the bonding indentation is typically subjected to significant mechanical stress, which, along with temperature, can affect the shape of all filament components within the bonding indentation area.

[0027] The term "single-component filament" or "single-component fiber" refers to a filament formed from a single polymer or a blend of polymers, which is different from bicomponent or multicomponent filaments.

[0028] The terms "multicomponent fiber" or "multicomponent filament" refer to fibers or filaments whose cross-section contains more than one individual component, each of which is composed of a different polymeric compound or a blend of different polymeric compounds. Therefore, the term "multicomponent fiber / multicomponent filament" is a broader term encompassing, but not limited to, "bicomponent fiber / bicomponent filament." The different components of a multicomponent filament are essentially arranged in well-defined regions along the cross-section of the filament and extend continuously outward along its length. A multicomponent filament may have a cross-section divided into several partial cross-sections composed of various components of arbitrary shapes or arrangements, including, for example, partial components arranged coaxially, and arbitrary arrangements of partial components in the form of core and sheath, radial, or so-called island cross-sections.

[0029] The terms “two-component” and “bicomponent” used to describe filaments are used interchangeably in this document.

[0030] The design of multicomponent filaments has a decisive influence on their crimp properties. A good way to identify the design of a multicomponent filament is to observe and evaluate its cross-section, which makes the positions of the different components of the filament visible. In most cases, the different components are made of different polymer formulations, which are selected and characterized by, for example, different melt temperatures and / or different shrinkage properties after spinning, quenching, stretching, and final fiber curing. Generally, the rotationally symmetric position of the filament components in their cross-section (e.g., concentric core / sheath) will result in non-crimped filaments, while the asymmetrical position of the filament components (e.g., side-by-side or eccentric core / sheath) will become different, potential crimping forces for achieving self-crimped and / or thermally activated crimped filaments. To simplify the language in this application, we use the terms "crimpable cross-section" and "non-crimpable cross-section" instead of "filament showing a cross-section supporting crimp" and "filament showing a cross-section not supporting crimp." The term "crestable cross-section" in this paper refers to a multicomponent fiber in which components with different shrinkage properties are arranged in a cross-section such that these filaments will self-crease during filament stretching and curing, or, when heated to or above the activation temperature and then slowly cooled, the fibers crimp, causing them to follow the vector of shrinkage forces. Thus, when the fiber is released, it produces what is called a helical crimp, although the mutual adhesion of the fibers when contained in a fiber layer does not allow for an ideal helix. For multicomponent fibers, we can determine the centroid of each individual component in the fiber cross-section (considering their area / position in the cross-section). Without being bound by theory, it is believed that a fiber is "non-crestable" when the centroid of all regions of each component is substantially at the same point as a concentric core / sheath described as rotationally symmetric. For example, for a circular bicomponent fiber with a symmetrical or central core / sheath cross-sectional structure, the centroid is located at the center of the cross-section (see [link to relevant documentation]). Figure 1).

[0031] The measurement of “filament diameter” is expressed in μm. The terms “grams per 9000m filament” (also denier or denier) or “grams per 10000m filament” (dTex) are used to indicate the fineness or coarseness of filaments because they involve multiplying the filament diameter (assuming a circular filament cross-section) by the density of one or more materials used.

[0032] "Machine Direction" (MD) - In relation to the manufacture of nonwoven fiber materials and the actual nonwoven fiber material itself, the term "machine direction" (MD) refers to the direction of forward movement of the nonwoven fiber material on the manufacturing line that manufactures the material.

[0033] "Cross Direction" (CD) - In relation to the manufacture of nonwoven fiber materials and the actual nonwoven fiber materials themselves, the term "cross direction" (CD) refers to a direction that is substantially transverse to the forward movement direction of the nonwoven fiber material on the manufacturing line that manufactures the material, while also being located on the plane of the nonwoven fiber material.

[0034] The “z-direction”—related to the fabrication of nonwoven fiber materials—is the direction perpendicular to the plane MD x CD. Extension in the z-direction describes the thickness of the nonwoven material.

[0035] "Nonwoven material" or "nonwoven fabric" refers to a strip or fiber formation produced from oriented or randomly oriented filaments, which are first formed during the production of filament layers, then bonded together by friction or the induction of cohesive or adhesive forces, and finally bonded together by mutual adhesion, which is accomplished by thermal (e.g., by the action of flowing air, calendering, ultrasonic effects, etc.), chemical (e.g., using adhesives), mechanical (e.g., hydraulic entanglement, etc.), or alternatively by a combination of these methods. This term does not refer to fabrics formed by weaving or knitting, or fabrics using yarns or fibers to form bonded seams. Fibers can be of natural or synthetic origin and can be short yarns, continuous fibers, or fibers manufactured directly at the processing location. Commercially available fibers range in diameter from less than about 0.001 mm to greater than about 0.2 mm and are supplied in various forms: short fibers (referred to as short fibers or cut fibers), continuous monofilaments (filaments or monofilament fibers), untwisted bundles of filaments (combed fibers), and twisted bundles of filaments (yarns). Nonwoven fabrics can be manufactured using a variety of methods, including techniques such as meltblowing, spunbonding, spunmelt spinning, solvent spinning, electrospinning, carding, membrane fibrillation, fibrillation, air-jet web formation, dry web formation, wet web formation with short fibers, and various combinations of these methods, as known in the art. The basis weight of nonwoven fabrics is typically expressed in grams per square meter (g / m²). 2 (or gsm) indicates.

[0036] The "spunbond" or "spunbond" method is a nonwoven fabric manufacturing method that involves directly converting a polymer into filaments, and then directly depositing the resulting filaments to produce a nonwoven filament layer containing randomly arranged filaments. This nonwoven filament layer is then consolidated in such a way that it surrounds the nonwoven fabric by creating an adhesive between the filaments. The consolidation process can be carried out using various methods, such as through air passage, calendering, etc.

[0037] The term "floc" refers to a material in the form of filaments found in its state prior to bonding, a process that can be carried out in various ways, such as air-through bonding, calendering, etc. The "floc" consists of individual filaments that are not typically bonded together, even if the filaments can be pre-bonded / pre-consolidated in some way, which can occur during or shortly after filament laying in the spinning process. However, this pre-consolidation still allows a considerable number of filaments to move freely, enabling them to be repositioned. The aforementioned "floc" can consist of several layers formed by depositing filaments from several spinning boxes during the spinning process.

[0038] In the sense used herein, the term "layer" refers to a portion of a fabric's components or elements. A "layer" can be the form of multiple filaments produced on a single spinning box or on two or more consecutively arranged spinning boxes, producing substantially identical filaments. For example, two consecutively arranged spinning boxes used to perform a spunbond process have substantially identical settings, and processing polymers with substantially identical compositions can be combined to produce a single layer. Conversely, two spunbond spinning boxes, one producing, for example, monocomponent filaments and the other producing, for example, bicomponent filaments, will form two distinct layers. The composition of a layer can be determined based on knowledge of the individual settings and components that determine the composition of the resin (polymer) used to produce the layer, or by analysis of the nonwoven fabric itself, for example, by using electron microscopy, or by analyzing the composition used to produce the filaments contained in the layer using DSC or NMR methods. Adjacent filament layers do not necessarily have to be strictly separated; layers in the boundary region may mix together due to the filaments of the later deposited layer falling into the gaps between the filaments of the earlier deposited layer. Individual layers in a nonwoven fabric can form typical structures (such as SMS), regardless of the layered structure. A layer can contain one, two, or even more layers.

[0039] As used herein, the term "stratum / strata" refers to a region of filaments that extends substantially along the plane of the MD and CD directions of the nonwoven fabric, has a certain thickness in the z-direction of the fabric, and has a substantially uniform filament density (i.e., filament mass per volume). The density of the filaments in a stratum within a nonwoven fabric cannot be measured precisely; however, it can be assessed when observed in a cross-section of the nonwoven fabric. The stratification can also be characterized by the bonding of filaments of substantially uniform density with each other and / or the bonding of stronger and weaker filaments of substantially uniform content (although slight gradients of these values ​​may exist from the outer surface of the outer stratum towards the middle region). It should be understood that the filament stratification within a nonwoven fabric is by no means perfectly uniform; because the filaments of a nonwoven fabric are randomly arranged and oriented, filaments from one stratum can enter another stratum, and furthermore, certain areas of a stratum can locally bulge or extend from the plane in which most of the stratum lies, and some filaments of a stratum can reach into adjacent strata or beyond the surface of the nonwoven fabric. The layered structure can be observed by analyzing the nonwoven fabric itself, for example by using an electron microscope (especially from a cross-sectional view), or by means of, for example, tomography or micro-CT measurements.

[0040] The term “compressibility” here refers to the distance, in millimeters, that a nonwoven fabric can be compressed by the action of a load defined during the “elasticity” measurement.

[0041] The term "resilient" here refers to the ability of a fabric to return to its initial shape after being compressed. This primarily refers to the regenerative capacity (resilience) of the fabric's bulkiness, based on the ratio between the fabric's thickness after the load is released and its initial thickness.

[0042] The term "sag ratio" or "draw ratio" in this article refers to a value calculated by dividing the cross-sectional area of ​​the capillary by the cross-sectional area of ​​the filament. The cross-sectional area of ​​the filament is calculated using fiber fineness measured based on its apparent diameter. Other non-circular cross-sections cannot be calculated in this way; therefore, in such cases, analysis of SEM images showing the actual cross-section is required. Attached Figure Description

[0043] Preferred embodiments of the invention will now be described in more detail with reference to the accompanying drawings, photographs, and 3D models, which illustrate...

[0044] Figure 1 It is an example of a rollable cross-section.

[0045] Figure 2 This is a cross-sectional SEM microscopy of an embodiment of the present invention.

[0046] Figure 3 This is a schematic cross-sectional view of an embodiment of the present invention.

[0047] Figure 4 This is a schematic cross-sectional view of another embodiment of the present invention.

[0048] Figure 5A This is a schematic plan view of the bonding between unbonded filaments.

[0049] Figure 5B yes Figure 5A A schematic cross-section of the filaments bonded together.

[0050] Figure 6A This is a schematic planar diagram of a weakly bonded type of filament bonding.

[0051] Figure 6B yes Figure 6A A schematic cross-section of the filaments bonded together.

[0052] Figure 7A This is a schematic plan view of a fully bonded type of filament bonding.

[0053] Figure 7B yes Figure 7A A schematic cross-section of the filaments bonded together.

[0054] Figure 8A This is a schematic plan view of the bonding between filaments in a trunk-type adhesive type.

[0055] Figure 8B yes Figure 8A A schematic cross-section of the filaments bonded together.

[0056] Figure 9 This is a cross-sectional photograph of an embodiment of the present invention when it is fixed in resin.

[0057] Figure 10 This is a cross-sectional SEM microscopy of an embodiment of the present invention.

[0058] Figure 11 This is a schematic diagram of a cross-section of a fabric with a very low filament-to-filament bonding density and a relatively large void volume.

[0059] Figure 12 This is a schematic diagram of a cross-section of a fabric with a uniform low filament-to-filament bonding density.

[0060] Figure 13 It is a schematic diagram of a cross-section of a fabric with a relatively small void volume and a high level of uniform filament-to-filament bonding density.

[0061] Figure 14 This is a schematic diagram of a cross-section of a fabric with a very high filament-to-filament bonding density and a small void volume.

[0062] Figures 15 to 19 The SEM microscopy of the nonwoven fabric according to the invention after delamination is shown, in which scars of broken adhesions are visible.

[0063] Figure 20A SEM microscopy showing a cross-section of an embodiment of the invention containing non-curled filaments.

[0064] Figure 20B SEM microscopy showing a cross-section of an embodiment of the invention containing non-curled filaments.

[0065] Figure 21 This is a schematic cross-sectional view of another embodiment of the present invention.

[0066] Figure 22 This is a cross-sectional SEM microscopy of an embodiment of the present invention.

[0067] Figure 23 This is a schematic diagram of a production line used to produce the nonwoven fabric of this invention.

[0068] Figure 24 This is a cross-sectional SEM microscopy of Example 1.

[0069] Figure 25 This is a cross-sectional SEM microscopy of Example 2.

[0070] Figure 26 This is a photograph of a cross-section of Example 2, which is fixed in the resin.

[0071] Figure 27 It is a 3D model of the X-ray tomography procedure in Example 1.

[0072] Figure 28 yes Figure 27 Digital cutting of 3D models

[0073] Figure 29 SEM microscopy of the cross section in Example 3

[0074] Figure 30 SEM microscopy of the cross section in Example 4

[0075] Figure 31 SEM microscopy of the cross-section in Example 5

[0076] Figure 32 SEM microscopy of the cross-section in Example 6

[0077] Figure 33 SEM microscopy of the cross section in Example 7

[0078] Figure 34SEM microscopy of the cross-section in Example 8

[0079] Figure 35 SEM microscopy of the cross section in Example 9

[0080] Figure 37 SEM microscopy of the cross section in Example 11

[0081] Figure 38 This is a perspective view of the equipment used for testing Martindale average abrasion resistance ratings.

[0082] Figure 39 It is a rating scale used for napping assessment in the Martindale Average Abrasion Rating Test.

[0083] Figure 40 and Figure 41 This is a schematic diagram of a delamination test.

[0084] Figure 42A and Figure 42B This is a photograph of a sample holder used in SEM microscopy.

[0085] Figures 43A to 43C These are photos of a retainer used in 3D tomography.

[0086] Figures 44 to 46 It is a 3D model of the sample for micro-CT analysis according to the present invention. Detailed Implementation Plan

[0087] Spunbond and / or spunmelt nonwoven fabrics are well-known in industry. Endless filaments manufactured using a spinning box are laid on a production belt to form a wadding, then pre-bonded and bonded together to form a fabric. The bonding step can be selected from several known options, such as:

[0088] - For example, mechanical entanglement caused by needles or water flow;

[0089] - Chemical bonding using adhesives or other additives added for bonding purposes;

[0090] Thermal bonding is achieved by exposing the wadding to heat to create bond points through the melting and solidification of at least a portion of the polymer composition. For example, heat can be provided by a pair of calendering rolls, by radiant heat, or by a hot fluid passing through the wadding.

[0091] Each of the listed methods, with its specific advantages and disadvantages, also imparts a typical appearance and properties to the corresponding fabric, which can be controlled using process settings within a given range. The list of examples provided above is for illustrative purposes only, and those skilled in the art will understand that other bonding methods or various combinations thereof can be used to achieve the desired properties of the fabric.

[0092] Fabrics bonded by hot fluid flow are industrially known, and in particular, the use of short fiber carding techniques is known for producing soft, thermally bonded fabrics. A major advantage of hot fluid bonding is that this bonding occurs throughout the fabric, where each individual fiber can form a bond with the fiber cross-section. The bond is smaller and forms between two or more fibers in contact with each other. Short fiber technology allows for the advantage of blending fibers together into a homogeneous fiber blend and precisely controlling the amount of fiber containing a polymer (bonding polymer) with a lower melting temperature. For example, when a very soft and bulky fabric is required, only a small amount of fiber with the binding polymer can be present in the fiber premix, and vice versa.

[0093] Conversely, spunbond nonwoven fabrics are typically produced from a single type of filament, and the amount of binder polymer can be controlled solely by the content of the binder polymer in each fiber (the polymer ratio in the bicomponent filament). A spunbond production line can contain multiple spinning boxes, and layered fabrics with different binder polymers can be produced through combinations of various ratios from each box. Layers with different binder polymer ratios can provide different properties, and fabrics can utilize the synergistic effects between highly and moderately bonded layers. Using the proportion of binder polymer in the filament composition as an example, more technical features can be combined, such as those described in Reifenhauser's application EP19189238.9 (not yet published), which began in 2018, describing a fabric with at least two layers, one providing high abrasion resistance and the other layers providing softness and bulkiness.

[0094] The above solution provides a fabric with the desired combination of properties, but from a process perspective, it hides a drawback for fabric producers. Optimal abrasion resistance and softness (in the sense of flexibility or drape) are achieved when the first layer forms a thinner skin only on the second layer. This means the first layer exhibits a lower basis weight, therefore a two-box production line cannot utilize the first box to achieve its optimal production volume.

[0095] Our invention provides a spunbond material in which the "skin" of the "soft-fluid" portion can be formed by setting a hot fluid flow bonding process, and the thickness of the "skin" can be controlled according to the desired final properties of the fabric.

[0096] The fabric according to the invention can be made from a wadding comprising multicomponent filaments, the multicomponent filaments containing a bonding polymer having a low melting temperature on at least a portion of their surface. The wadding on the moving belt is exposed to heat treatment. Heat can be transferred to the wadding via a hot fluid (e.g., hot air). Typically, heat can be transferred to the wadding at different stages of the production process, for example, directly after the filaments are laid on the belt to pre-consolidate the structure, during the heat activation process, during the bonding process, etc.

[0097] A hot fluid penetrates the surface of the filament pad, flows around the filaments, and some of the heat carried by the hot fluid is transferred to the cooler filaments. As some heat is transferred to the filaments on the pad surface, the temperature of the hot fluid decreases slightly, as does the temperature difference between the filaments and the hot fluid. Those skilled in the art will recognize that as the filaments at the surface acquire this heat, their temperature rises while the temperature difference between the hot fluid and the filaments decreases. With sufficient time and heat, all the filaments within the fabric can be heated to a uniform temperature, and fiber-to-fiber bonding can be uniform across the entire fabric thickness. Therefore, the fabric can be uniformly, completely, or well bonded.

[0098] Surprisingly, fabrics with a non-uniform density of bonding points throughout their thickness can offer additional advantages. When viewed in cross-sectional regions, the fabric according to the invention comprises regions with greater inter-filament bonding (more filaments in contact with each other, thus allowing for, for example, more filament-to-filament bonding and / or stronger bonding) and regions with lesser inter-filament bonding; where bonding is defined as all possible interactions between individual filaments, i.e., bonded, partially bonded or non-bonded contact, crossing, interconnecting, parallel contact, etc. (defined in more detail below). For a given type of filament (based on fiber surface properties), the distinction between these regions is related to the filament density of that type of filament (the number of filaments in a given region). Regions with higher bonding typically form on the outer surface of the filament pads into which hot fluid enters the fabric. Regions with higher or lower filament densities (layers) are generally well identifiable; however, there are usually no strict boundaries between them. The fabric according to the invention contains at least two distinct filament layers throughout its thickness.

[0099] Delamination is typically defined as 3D regions oriented in the planar MD-CD direction, which have generally uniform filament-to-filament bonding levels and / or filament densities. The formation of such delamination can be influenced by various factors and can be identified using several methods.

[0100] For example, stratification with a high level of interfilament bonding also has a high filament density or fiber density. The filaments are closer together than in stratifications formed from the same wadding, but have less fiber-to-fiber bonding. The fiber density level can be estimated by observing, for example, a cross-section under a SEM microscope. Figure 2 As shown, it can be analyzed and calculated, for example, by computed tomography or micro-CT measurements, which can produce 2D digital cross-sections and be used to accurately determine filament density.

[0101] For example (see Figure 3 The fabric according to the invention may include at least two filament layers (A, B) with different filament densities in its thickness. Preferably, the ratio of the filament density of layer A to the filament density of layer B is at least 1.5; more preferably at least 2.0; more preferably at least 2.5; more preferably at least 3, and even more preferably at least 5.

[0102] For example, the fabric according to the invention may include at least two different filament layers, wherein a first layer (A) with a higher filament density forms one surface of the nonwoven fabric, while a second layer (B) with a lower filament density forms the middle region or second surface of the nonwoven fabric.

[0103] For example (see Figure 4 The fabric according to the invention may include at least three different layers, wherein there is a first layer (A) forming a first outer surface of the fabric, a second layer (B) and a third layer (C) forming a second outer surface of the fabric, wherein the second layer (B) is arranged between the first layer (A) and the third layer (C). The filament density of the second layer (B) forming the intermediate region is lower than that of the first layer (A) and the third layer (C). It should be noted that the outer layers (A, C) may, but do not need to, have the same characteristics, as long as they have a higher filament density than the (inner) second layer (B). Preferably, the ratio of the filament density of the first layer (A) to the filament density of the second layer (B) is at least 1.5; more preferably at least 2.0; more preferably at least 2.5; more preferably at least 3, and even more preferably at least 5. Also preferably, the ratio of the filament density of the third layer (C) to the filament density of the second layer (B) is at least 1.5; more preferably at least 2.0; more preferably at least 2.5; more preferably at least 3, and even more preferably at least 5.

[0104] For example, the bonding density between filaments can be measured directly. It can also be estimated using optical or SEM microscopy, for example. Both methods are only applicable to the analysis of the surface of fabric samples. For complete sample analysis, an industrially known method for "determining the geometric fiber statistics of nonwoven fabrics" involves converting three-dimensional microscopic CT images into a model of the fabric. This method uses machine learning to identify individual fibers present in the sample, followed by geometric analysis of these fibers to obtain statistical information suitable for characterizing the material. The results include fiber orientation and density distribution. This analytical workflow was developed by Math2Market GmbH and is part of the GeoDict digital materials laboratory.

[0105] For example, the fabric according to the invention may include at least two different filament layers (A, B) with different interfilament bonding densities in its thickness. Preferably, the ratio of the interfilament bonding density of the first layer (A) to the interfilament bonding density of the second layer (B) is at least 2; more preferably at least 3; more preferably at least 4; more preferably at least 5, and even more preferably at least 7.

[0106] For example, the fabric according to the invention may comprise at least three different layers, including a first layer (A) forming a first outer surface of the nonwoven fabric; a second layer (B); and a third layer (C) forming a second outer surface of the fabric, wherein the second layer (B) is disposed between the first layer (A) and the third layer (C). The interfilament bonding density of the first layer (A) and the third layer (C) is higher than that of the layer (B) forming the middle region of the fabric. It should be noted that the outer layers (A, C) may, but need not, have the same characteristics, as long as they both have a higher interfilament bonding density than the (inner) third layer (B) which has the lowest interfilament bonding density. Preferably, the ratio of the interfilament bonding density of layer (A) (or the third layer (C)) to the interfilament bonding density of layer (B) is at least 2; more preferably at least 3.0; more preferably at least 4; more preferably at least 5, and even more preferably at least 7.

[0107] Filament bonding

[0108] The density of interfilament bonding is related to the bonding density within the fabric, or to the length of the filament portion between the bonding points. It should be noted that not every interfilament bond results in adhesion; if so, different types of adhesion can be identified based on the filament composition and surrounding conditions. Without being bound by theory, we believe four typical cases can be named:

[0109] 1) Unbonded—Two filaments can come into contact with each other, but no bond is formed (see [reference]). Figure 5A , Figure 5BFor example, in the case of side / side fiber types, where the polymer bonding exists only on a portion of the filament surface, the filaments can face each other through the portions where the bonding polymer is absent. Therefore, the filaments can contact each other, but cannot connect or bond together. Furthermore, for example, in the case where the fabric is bonded and the filament crimp is subsequently reactivated using a process that does not reach the melting temperature of the bonding polymer, the filaments can become entangled, thereby creating more filament-to-filament contact points; however, no new / additional filament-to-filament bonding is created.

[0110] 2) Weak or tangential bonding—Two filaments may be in contact with each other tangentially, and the bonding polymer creates a “neck” between them (see [link]). Figure 6A , Figure 6B This can happen, for example, when the fibers are in only slight contact with each other, or when only a small amount of bonding polymer is available.

[0111] 3) Fully bonded—Two filaments meet each other, and a bonding polymer covers them through a combined sheath (see...). Figure 7A , Figure 7B This can occur, for example, when the fibers are slightly pressed against each other, or, for example, when there is a large amount of binder polymer available to form the coating.

[0112] 4) "Trunk"—Two filaments are in longitudinal contact with each other, and the bonding polymer forms a neck or combined coating for the two fibers along a certain length, for example, a certain length greater than the sum of the diameters of the two bonding filaments (see...). Figure 8A , Figure 8B ).

[0113] It should be noted that more than two fibers can form a bonding point, and different bonding point types can be combined. For example, a trunk with weak / tangential bonding can be bonded to a third fiber, etc. It should also be noted that the categories presented are typical examples for illustrative purposes, and in reality, various types of bonding can be found in fabrics, especially temporary types of bonding between weak and full bonding, and trunks can be formed from very short to very long bonding.

[0114] For example, layers with a higher number of interfilament bonds can have higher bond density 3 (fully bonded) and 4 (trunk) than layers with a lower number of interfilament bonds.

[0115] For example, the fabric according to the invention may comprise at least two different filament layers (A, B) with different levels of fully bonded density and trunk-type bonded density in its thickness. Preferably, the ratio of fully bonded density to trunk-type bonded density in the first layer (A) and the second layer (B) is at least 1.5; more preferably at least 2.0; more preferably at least 3.0; more preferably at least 4.0, and even more preferably at least 5.

[0116] For example, the fabric according to the invention may comprise at least three different layers, including a first layer (A) forming a first outer surface of the nonwoven fabric; a second layer (B); and a third layer (C) forming a second outer surface of the fabric, wherein the second layer (B) is disposed between the first layer (A) and the third layer (C). The combined density of full bonding and trunk-type bonding in the first layer (A) and the combined density of full bonding and trunk-type bonding in the third layer (C) are higher than the combined density of full bonding and trunk-type bonding in the second layer (B). It should be noted that the outer layers (A, B) may, but need not, have the same characteristics, as long as they have a higher combined density of full bonding and trunk-type bonding than the (inner) second layer (B). Preferably, the ratio of the combined density of full bonding and trunk-type bonding of the first layer (A) (or the third layer (C)) and the layer (B) is at least 1.5; more preferably at least 2.0; more preferably at least 3.0; more preferably at least 4.0, and even more preferably at least 5.0.

[0117] All four types of bonding can be found in a single fabric sample. Bond strength increases from the first choice (no bonding) to weak / tangential bonding to full bonding and trunk bonding. The number and proportion of different types of bonding points in the fabric can affect the final fabric properties. For example, a higher number of bonds with higher strength can support the fabric's durability and tensile strength, but may also impart stiffness. In particular, a higher number of trunk bonds combined with a larger void volume can form to produce, for example, undesirable internal hard spots, which can be negatively rated as rough or uncomfortable abrasion.

[0118] For example, when observed in cross-section, various void volumes can be seen in nonwoven fabrics. Larger void volumes, referred to as "cavities," are visible in the cross-section of the nonwoven web and are three-dimensional. Typically, regions with higher levels of interfilament bonding have smaller void volumes, and the total void volume over the entire region is generally lower. Conversely, for a given region, regions with fewer interfilament bonds exhibit larger void volumes and larger total void volumes. Large voids, also called cavities, can also be observed in the cross-section of the fabric. In a cross-section along the longitudinal axis (MD) of the nonwoven fabric, the length of the cavity is significantly greater than its height.

[0119] For example, the nonwoven fabric according to the invention may include a layer B containing cavities, wherein the length-to-height ratio of the cavities L:H is at least 3:1, preferably 5:1, and most preferably 10:1. See, for example. Figure 9 and Figure 10 .

[0120] Nonwoven fabrics themselves can be analyzed using various types of microscopes or other visualization techniques to describe the differences in their fiber structure, but from the end-user's perspective, fabric properties are the key advantage. Free from theoretical constraints and assuming that nonwoven fabrics are made from uniform filament mats composed of identical filaments, where the level of bonding between the filaments is proportional to the density of the bond, we can predict the final performance based on the density level of the bonding between the filaments.

[0121] For example, a single-layer wadding exposed to spunbond air-through bonding will be exposed to pre-consolidation on a belt, where hot fluid enters the fabric from the top, and then the wadding moves to an air-through bonding unit and is bonded to the belt or roller, where hot fluid enters the wadding from the same side as the pre-consolidated air. Based on specific technical and process conditions, various structures with different properties can be formed:

[0122] When insufficient heat enters the filaments of the padding, the bonding polymer cannot soften or melt sufficiently, and any bond formed is typically weak. The resulting fabric usually provides a very low level of inter-filament bonding density and a relatively large void volume. Such a fabric can be described as “underbonded.” Typically, it is prone to filament breakage or partial filament removal, and durability (surface and delamination / breakage) is very low. The fabric can even be considered unstable. On the other hand, such a fabric can be very soft in terms of compressibility, flexibility, and drape. See also Figure 11 .

[0123] When heat (possibly at the lower end of a suitable heat range) enters the padding filaments, especially when the heat is distributed as evenly as possible throughout the padding with sufficient time to penetrate the filaments, or, for example, when the padding is so permeable to heat flow that the heat flows through the padding filaments at all locations with the same temperature gradient (suitable process settings can be readily determined by those skilled in the art), the polymer is sufficiently softened or melted (at the lower end of a suitable bonding range) and filament-to-filament bonding is achieved. The resulting fabric typically provides a uniformly low level of interfilament bonding density and still a relatively large void volume. Such a fabric may be referred to as “low-bonding.” Typically, it is bulky (loose) and soft in terms of compressibility, flexibility, drape, etc., but it maintains a certain (lower) level of surface and delamination resistance. See also Figure 12 .

[0124] When heat enters the filaments of the padding and is not evenly distributed, causing the fibers in the outer area to receive more heat and the fibers in the inner part of the fabric to receive less heat (from the perspective of the direction of the incoming heat flow), a layered structure can be formed.

[0125] Layered structures require a higher level of interfilament bonding density on the outer surface and a lower level of interfilament bonding density inside the fabric. See also Figure 3 .

[0126] Heat can enter the filament mat simultaneously from one side or from both sides (e.g., from a hot airflow and hot surface, such as a belt, table, roller, etc., on one side; from the other side) or from both sides in separate steps (from one side and then from the other side). In this case, a first layer (A) with a higher level of inter-filament bonding density can be formed on the first outer surface, a third layer (C) with a higher level of inter-filament bonding density can be formed on the second outer surface, and the intermediate region may include a second layer (B) with the lowest level of inter-filament bonding density. See also Figure 4 .

[0127] Unbound by theory, we believe that more process elements and parameters can work together to form a layered structure. For example, slight compressive forces under heating (e.g., tension of fabric on a cylindrical surface, such as a roller or drum) can support the formation of outer layers at a high level of interfilament bonding density. For example, heat entering the filaments can soften or partially soften the non-bonding polymer in the polymer composition, and partial softening of the filaments closest to the heat source can contribute to the formation of the outer layer. For example, filaments with a crimpable cross-section or containing shrinkable polymers can attempt to move from a semi-stable state to a more stable state under the influence of heat, and even if this process is insufficient to form crimp, internal filament forces can support layer formation. Patent application WO2020103964 describes the theory of internal shrinkage forces and fiber / filament durability thresholds to explain the formation of a fluffy structure with an uncrimpable cross-section. Unbound by theory, we believe that similar principles can be used in a furnace to describe the forces that move a portion of a filament in the z-direction to form a layered structure. For example, cooling immediately after leaving the furnace can contribute to the formation or at least set the formed layered structure.

[0128] The fabric formed according to the invention provides a very good combination of properties within its structural layers having high and low inter-filament bonding density levels, wherein good durability (the surface durability of the layers with high inter-filament bonding density levels and the high force required for delamination given by the bonding strength of the weakest layer B with low inter-filament bonding density levels) is combined with good bulkiness and softness (in the sense of compressibility, flexibility, drape, etc.) supported by loose layers with low inter-filament bonding density levels.

[0129] Unbound by theory, we believe that the balance between softness / fluffiness and durability / tensile strength properties can also be achieved by utilizing the synergistic effect provided by the unclear boundaries between adjacent layers. For example, some filaments may have portions extending into the first or third layers (A, C) with a higher level of interfilament bonding density, while other portions extend into the second layer (B) with a lower level of interfilament bonding density. For example, a layered structure formed within a single filament pad provides better internal complexity compared to a similar structure formed from different fiber layers. When heat (possibly at a moderate to high level within a suitable heat range) enters the pad filaments, especially when there is sufficient time for the heat to enter the filaments as uniformly as possible throughout the fabric, or, for example, when the pad is so permeable to heat flow that the heat flow passes through the pad filaments at all locations with the same heat gradient (more suitable process settings can be readily determined by those skilled in the art), the polymer is sufficiently softened or melted (at the higher limit of a suitable bonding temperature range), resulting in filament-to-filament bonding. The resulting fabric typically provides a uniformly high level of interfilament bonding density with a relatively small void volume. This type of fabric can be described as "fully bonded." It is typically small in volume and relatively stiff. It also maintains a high level of surface resistance, especially resistance to delamination. See also Figure 13 .

[0130] When too much heat enters the filament wadding, the bonding polymer melts completely, resulting in primarily a fully bonded or trunk-type bond. Additionally, other polymers from the filament composition may be affected; for example, they may become more pliable, and the filament wadding may collapse on its own. The resulting fabric typically offers a very high level of interfilament bonding density and a small void volume. This type of fabric can be described as "over-bonded." It is usually very stiff and durable. It may also be less fluffy and have a poorer feel. See also Figure 14 .

[0131] It should be noted that the assumption that fabric thickness decreases with increasing heat absorption is valid for filaments that do not undergo significant changes, which trigger internal forces that alter the filament shape during their bonding process (e.g., crimp activation, controlled shrinkage, etc.). In this case, the fabric can have a thickness different from the heat absorption curve, exhibiting one or more cambers at the optimal crimp / shrinkage values, while having a lower thickness for both under-bonded and over-bonded fabrics. The bonding principle is generally the same, and a layered structure with all its advantages can be formed.

[0132] It is well known in industry that certain combinations of polymers with different shrinkage levels arranged in a so-called curlable cross-section provide what is known as curl. This can be direct self-curling or potential curling, where the fibers must be activated to exhibit curling (e.g., by thermal activation). Fibers with a curlable cross-section provide regular curling that forms what is known as helical curling. By considerable simplification, we can say that fibers with a curlable cross-section tend to bend in the direction toward the component with the higher shrinkage rate, resulting in substantially uniform helical curling. In other words, the curlable cross-section causes a regular movement of the internal force vectors of the first and second components toward each other. Unbound by theory, we consider the regularity of displacement to be the primary cause of the regularity of curling in free single fibers. Conversely, according to our invention, unbound by theory, in fibers with a non-curable cross-section, we believe that the internal shrinkage force vectors of the first and second components do not provide any regular offset between them, thus the fibers form irregular bows or waves in arbitrary directions. By considerable simplification, we can say that the fibers do not have a uniform tendency to bend toward a particular portion of their cross-section or edge, resulting in their irregular final shape. After activation, the fiber cross-section remains essentially non-curlable.

[0133] For example, fabrics according to the invention may comprise multi-component filaments having a bonding polymer on at least a portion of their surface. The bonding polymer may be selected from polyolefins (i.e., polypropylene or polyethylene), low-melting-point polymers (including low-melting-point polyester grades (i.e., aliphatic compounds such as polylactic acid, or aromatic compounds such as polyethylene terephthalate)), copolymers or blends of suitable polymers. Within the scope of the invention, the bonding polymer consists of, or substantially consists of, a plastic comprising, polyesters including polyester copolymers (coPET) or polylactide copolymers (COPLA).

[0134] For example, the fabric according to the invention may comprise a multi-component filament having a first polymer having a melt temperature higher than that of the binding polymer, preferably a melt temperature difference of at least 5°C. The first polymer may be selected from polyolefins (i.e., polypropylene or polyethylene), polyesters (i.e., aliphatic compounds, such as polylactic acid, or aromatic compounds, such as polyethylene terephthalate), copolymers or blends of suitable polymers. Within the scope of the invention, the first polymer consists of or substantially consists of a plastic comprising the group consisting of polyesters further comprising polyester copolymers (coPET) or polylactide copolymers (COPLA).

[0135] Preferred combinations of components used in the bicomponent filaments according to the present invention are PP / PE, PET / PE, PET / PP, PET / COPET, PLA / COPLA, PLA / PE, and PLA / PP.

[0136] For example, the fabric according to the invention may include multi-component filaments, preferably bicomponent filaments.

[0137] The fabric according to the invention is formed from a bulky wadding, preferably from a wadding comprising crimped filaments or filaments having potential crimp that can self-crimp upon appropriate activation.

[0138] For example, the fabric according to the invention may comprise multicomponent filaments having a crimpable cross-section, preferably bicomponent filaments having a crimpable cross-section, and more preferably filaments having an eC / S or S / S cross-section. For example, some preferred combinations for the eC / S cross-section are: PP / PE, PET / PE, PLA / PE, PET / PP, PLA / PP, PP / coPP, PET / coPET, PLA / coPLA, wherein the specified polymer forms at least 75% of the filament component.

[0139] For example, the fabric according to the invention may comprise multicomponent filaments having a non-crimpable cross-section, the multicomponent filaments comprising a shrinkable polymer, preferably bicomponent filaments having a C / S cross-section, the bicomponent filaments comprising polyester in their composition, preferably in the core. For example, some preferred combinations of C / S cross-sections are: PET / PE, PET / PP, PET / coPET, PLA / PE, PLA / PP, PLA / coPLA, wherein the specified polymer forms at least 75% of the filament component.

[0140] Unbound by theory, we believe that layered structures can be formed under certain conditions, but due to the low amount of binder polymer available on the filament surface, the resulting bond is too weak to hold it in place, and the desired structure is lost. On the other hand, if the filament contains too much binder polymer that melts during the bonding process, the remaining solid portions of the unmelted filament become too weak to maintain their structure under heat flow, and the desired structure again is lost.

[0141] For example, the fabric according to the invention may contain at least 15% by weight of the bonding polymer, preferably at least 18% by weight of the bonding polymer.

[0142] For example, the fabric according to the invention may contain up to 75% by weight of the bonding polymer, preferably up to 80% by weight of the bonding polymer.

[0143] Different levels can be used for various polymer combinations. For example, a fabric with PP / PE filaments according to the invention may contain at least 25% by weight of the binder polymer, preferably at least 30% by weight, and more preferably at least 35% by weight. For example, a fabric with PP / PE filaments according to the invention may contain up to 75% by weight of the binder polymer, preferably up to 70% by weight, and more preferably up to 65% by weight.

[0144] It should also be noted that the bonding polymer should be present on the surface of the filament. In the case of a core-sheath or eccentric core-sheath, the bonding polymer should be part of the sheath or preferably form part of the sheath.

[0145] For example, fabrics according to the invention may include a bonding polymer that forms at least 20% of the filament surface area, preferably at least 35%, and even more preferably at least 50%. The layered structure according to the invention provides a balance between fabric durability and softness / bulkness.

[0146] For example, fabric durability is always required. Fabrics need to be durable enough to withstand the process of transformation into the final product without damage, and also to withstand the use of the final product. Two very important aspects of durability are fabric surface stability (durability of fibers released from the surface) and fabric delamination stability (durability of the upper part of the fabric torn from the bottom). Typically, these two types of durability are evaluated along with other types of durability, such as abrasion resistance using the Martindale test method with a set number of cycles, and the results are subsequently manually evaluated on a scale of 1 to 5. This test is good for setting threshold levels for a particular product with a binary pass / fail assessment; however, due to its coarse grading and lack of additional information for comparing samples that pass the test with the best results, it is not the best choice for the sufficiently detailed distinctions needed to describe the advantages of the present invention.

[0147] In other words, we can say that the tensile strength of a fabric in the z-direction is low for delamination with a low level of interfilament bonding. The tensile strength of a fabric in the z-direction can be measured, for example, using a delamination strength test. A fabric tears in its weakest layer. When the delamination strength is too low, the fabric is not stable enough and under transition or normal operating loads, it may delaminate and tear into individual layers, or it may delaminate only in certain areas where the delaminated portions remain partially connected and tend to produce undesirable clumps. Similarly, even if the fabric surface is very abrasion-resistant, delamination will worsen the results during the Martindale abrasion test, producing clumps or a so-called spiderweb effect.

[0148] Unbound by theory, we believe that for fabrics with formed delamination structures, the key value describing durability is delamination strength. Fully bonded fabrics with no delamination or a low level of delamination will exhibit good surface stability and high delamination strength. Well-formed delamination is characterized by good surface stability and moderate delamination strength. Inadequately bonded fabrics with weak or no delamination are characterized by easy surface disintegration and low delamination / disintegration strength.

[0149] For example, the fabric according to the invention may contain at least two different layers, wherein the delamination strength is equal to or greater than 0.5N or preferably greater than 0.6N or preferably greater than 0.7N or preferably greater than 0.8N.

[0150] For example, the fabric according to the invention may include at least two different layers, wherein the delamination strength is equal to or less than 2.0N.

[0151] Delamination force is the force required to pull apart the outer portion / outer layer of a nonwoven fabric along its weakest point. Assuming the fabric has a delamination-forming structure, delamination will occur within the layer having the lowest level of interfilament bonding density. It should be noted that for typical nonwoven compositions, the bonding polymer provides lower tensile strength than other polymers, meaning the weakest point is usually the bond rather than the filaments themselves. This property is also often affected by the fiber cross-section. For example, polyethylene as a bonding polymer provides lower tensile strength than polypropylene or polyester. For instance, the bond between filaments in a core / sheath structure with polyethylene within a sheath is relatively weak because the sheath is typically a fairly thin coating of the inner core. Therefore, the filament-to-filament bond is generally easier to break than the filaments themselves. See also Figures 15 to 19 .

[0152] For example, bulkiness is one of the key characteristics. As mentioned above, the filament mat should be sufficiently bulky to allow proper flow of hot fluids during bonding processes, such as air-through bonding. The final fabric should also be bulky, as bulkiness is very important to human perception, and a more bulky fabric is often perceived as softer. Layered structures provide bulkiness; for example, layer B is typically very bulky, increasing the overall bulkiness of the structure. On the other hand, one or more layers with a high level of interfilament bonding density reduce the overall bulkiness of the structure, and in extremely bulky structures, one or more outer layers may not form at all.

[0153] For example, the fabric according to the invention can have a weight of less than 60 kg / m². 3 Preferably less than 58kg / m 3 More preferably less than 56 kg / m 3 More preferably less than 54 kg / m3 Loose density.

[0154] For example, the fabric according to the invention can have a weight greater than 15 kg / m². 3 Preferably greater than 20kg / m 3 More preferably greater than 25 kg / m 3 The optimal value is greater than 30 kg / m 3 Loose density.

[0155] Loftiness / bulkness indicates the number of kilograms per cubic meter; therefore, the lower the value, the more fluffy the material. We can also use dm... 3 The "thickness to basis weight ratio" is expressed in liters (L / kg) to represent the volume of one kilogram of fabric. The higher the value, the greater the loft.

[0156] For example, the fabric according to the invention may have a thickness-to-basis weight ratio of at least 16.5 l / kg, preferably at least 17.0 l / kg, more preferably at least 18.0 l / kg, and more preferably at least 18.5 l / kg.

[0157] For example, the fabric according to the invention can have a bulk density of up to 66 l / kg, preferably no more than 50 l / kg, more preferably no more than 40 l / kg, and more preferably no more than 33 l / kg.

[0158] For example, the fabric according to the invention may have a basis weight of at least 5 gsm, preferably at least 10 gsm, and more preferably at least 15 gsm.

[0159] For example, the fabric according to the invention may have a basis weight of no more than 200 gsm, preferably no more than 150 gsm, and more preferably no more than 100 gsm.

[0160] For example, the fabric according to the invention may have a resilience of at least 0.5 (which corresponds to 50% of the original thickness), preferably at least 0.6, more preferably at least 0.7, more preferably at least 0.8, and most preferably at least 0.9.

[0161] For example, the fabric according to the invention may have at least 5%, preferably at least 10%, more preferably at least 13%, more preferably at least 15%, and more preferably at least 18% resilience.

[0162] The above description of the layered structure, especially as illustrated in the diagram, assumes that the filaments are uniformly laid out in all three dimensions of the wadding. This uniformity is ideal for most nonwoven fabric applications. Nonuniformity is usually directly observable to the human eye. The fabric may appear denser / thicker in some areas and less dense / thinner / weaker in others. In extreme cases, the fabric may appear to consist of dense islands spaced apart from each other, connected by sparse filament webs. However, even fabrics perceived as uniform by a human observer may contain small areas of nonuniformity with higher and lower densities in all three dimensions. Fibers with crimps, typically produced by self-crimping, activated crimping, or controlled shrinkage, tend to form structures characterized by higher and lower density areas, i.e., forming microagglomerates in some areas while leaving relatively empty microspaces in others. When examined at a microscale in the cross-section of the fabric, denser areas may partially form veneer layers with fewer interfilament bonds, and vice versa. See also Figure 20A and Figure 20B .

[0163] The purpose of this invention is to describe the layered structure and its advantages compared to layering methods. As described above, a layered structure can be formed in a single layer of a nonwoven fabric, or in other words, a layered structure can be formed independently of the fabric layers.

[0164] Layered structures can be advantageously combined with layering. For example, the fabric according to the invention can consist of two or more filament layers, wherein the filaments of at least one outer layer are configured as at least one outer layer and at least one other layer, the outer layer providing a higher level of inter-filament bonding density and the other layer having a lower level of inter-filament bonding density.

[0165] As described in detail above, a single layer may comprise one, two, or more layers. Typically, a layer may form part of a layer, may be equal to a layer, or may include more layers. Within the scope of this invention, we contemplate layered fabrics comprising at least one layer, in which at least two layers are formed.

[0166] For example, the fabric according to the invention comprises at least one layer of unended filaments, wherein at least two layers are formed.

[0167] For example, layers with different filament thicknesses and amounts of binder polymer can be combined to obtain fabrics with, for example, very good abrasion resistance (provided by layers with finer fibers and a higher amount of binder polymer) and overall bulkiness (provided by layers with coarser fibers and a lower amount of binder polymer), as described, for example, in Reifenhauser patent application number EP19189238.9 (not yet published).

[0168] For example, layers with different amounts of binder polymer on the filament surface can be combined together, such as S / S and C / S or eC / S filaments can be combined together to produce fabrics that have enhanced soft and bulky properties provided by the filament layers with a lower amount of binder polymer, and very good abrasion resistance on the filament surface with a higher amount of binder polymer.

[0169] Those skilled in the art can utilize the advantages of the layered structures formed in some or all of them to understand the various layer combinations. The filament layers of the layered structure can also be advantageously combined with one or more short fiber layers, membranes, etc.

[0170] Layering can also achieve specific layered structures produced by exposing the wadding to various heat sources. For example, a bulky fabric formed from two layers can be structured with five layers exhibiting alternating levels of high and low interfilament bonding density, the two layers being manufactured using two spinning boxes, pre-consolidated with hot air, and then bonded in a hot air furnace. See also Figure 21 and Figure 22 .

[0171] Unbound by theory, we believe that, in certain circumstances, an inner layer with a lower filament bonding density level located between two layers of lower filament bonding density can be supported by pre-consolidation of the wadding, wherein, for example, a heat fluid source (such as a hot air knife) and / or a second or any other heat fluid source (as required by production) after one, some or each manufacturing box is set together with a vacuum device below the belt can help to form a higher filament bonding density core and thus provide a greater possibility of forming a layered structure with a higher internal filament bonding density level in the fabric.

[0172] Similar structures can also be produced, for example, using specific layer combinations. For instance, a two-layer fabric, both composed of crimpable fibers with different levels of internal filament crimp (e.g., different filament cross-sections, different component ratios, different process settings that produce different levels of potential crimp, etc.), will result in independent filament movement in both layers, thereby forming a layer with a higher level of interfilament bonding density on the surface of the layers, in other words, on both the fabric surface and the boundary region between the layers.

[0173] The fabric according to the invention can be produced from a wadding comprising multi-component filaments, the multi-component filaments containing a bonding polymer having a low melting temperature on at least a portion of their surface. The wadding on the moving belt is heat-treated. Heat can be transferred to the wadding via a hot fluid (e.g., hot air). Typically, heat can be transferred to the wadding at different stages of the production process, for example, immediately after the filaments are laid on the belt to pre-consolidate the structure, during the thermal activation process, during the bonding process, etc.

[0174] A hot fluid enters the surface of the filament mat, flows around the filaments, and some of the heat carried by the hot fluid is transferred to the cooler filaments. Because some heat is transferred to the filaments on the mat surface, the temperature of the hot fluid decreases slightly, and the temperature difference between the filaments and the hot fluid also decreases slightly. Those skilled in the art will recognize that when the filaments on the surface are heated, the filament temperature rises, and the temperature difference between the hot fluid and the filaments decreases. With sufficient time and heat, all the filaments within the fabric can be heated to a uniform temperature, and fiber-to-fiber bonding can be uniform across the entire thickness of the fabric. The fabric can be described as uniformly, completely, or well-bonded.

[0175] It should be noted that the formation of filament-to-filament bonding also depends on the intensity of local fluid resistance pressure. That is, filaments may come into contact with or intersect each other, and they will not form a bond, or only a weak bond, while filaments in stronger contact will form a stronger bond through the molten polymer at a lower melting temperature. The pressure generated when hot air flows through the fabric along the main vertical hot fluid path of the fabric due to the dynamic fluid resistance causes the fluid temperature and its energy transfer capacity to subsequently decrease, gradually decreasing from the first point of impact on the exposed fabric surface to the other side of the fabric, while the temperature and fluid velocity are lower when leaving the fabric. This results in differences in bond density across the fabric cross-section, which manifests in the formation of delamination within the fabric layers.

[0176] The product according to the invention requires protection against non-uniform interfilament bonding density throughout its thickness. The process setup and machinery used to manufacture such a product from filament nonwoven wadding should be able to provide the required hot air constants via flow rates and temperatures in both CD and MD, meaning that they are constant over time. This requirement applies to all hot air supply devices, such as hot air knives, hot air zones, hot bonding ovens with rollers, flat belt ovens, or combinations of roller bonding and flat belt bonding.

[0177] In a preferred form of the invention, multi-component or preferably bi-component filaments are produced by spinning in a spinneret or using a spinneret and subsequently, preferentially, passing through a cooler. Within this cooler, the filaments are typically cooled by a fluid flow, primarily by cooling air. The scope of the invention includes the fact that the spun filaments are subsequently also passed through a drawing mechanism, where they are processed by being stretched. The stretched (elongated) filaments are then deposited on a moving belt, where they form a filament mat. In an advantageous configuration, filaments with a controlled potential shrinkage can be produced in the mat by adjusting specific parameters that determine the draw ratio. In other advantageous combinations, filaments providing self-curling or having a desired potential crimp level can subsequently be formed in the mat by setting a crimpable filament cross-section and adjusting specific parameters that determine the draw rate and cooling.

[0178] In a preferred form of the mechanical and methodological construction according to the invention, the inserted diffuser serves as a reservoir mechanism that controls the deposition of the filament and is mounted between the drawing mechanism and the filament deposition position. The scope of the invention includes the use of at least one diffuser, with the opposing sidewalls of the diffuser bifurcating relative to the filament's direction of passage. A highly recommended form of the invention is characterized by the design of the drive units for the cooling and drawing mechanisms as a closed system. Within this closed system, no additional air source is used, which supplements the supply of external cooling medium or cooling air to the cooling mechanism. Such a closed system has proven particularly suitable for the manufacture of nonwoven fabrics.

[0179] In the case of manufacturing nonwoven fabrics according to the invention using shrinkage, it has been found that the technical solution according to the invention for eliminating problems related to filament shrinkage is particularly reliable and effective when using the aforementioned unit, especially when a diffuser is used in addition to the particularly preferred configuration, with the diffuser arranged between the stretching mechanism and the filament deposition position. It has been explained that the shrinkage rate of the nonwoven wadding manufactured by spunbond can be adapted or adjusted very specifically by parameters such as the stretch ratio, cooling air / polymer ratio, and filament speed.

[0180] In the case of manufacturing nonwoven fabrics according to the invention using self-crimping filaments, these filaments are released from aerodynamic stretching force as they leave the diffuser located at the end of the stretching chamber and are subsequently laid in a vacuum-supported web-forming zone, wherein the filaments crimp once the vacuum is at its minimum force (on the MD) at the edge of the suction zone, and the final increase in fabric thickness is obtained by such crimping of the filaments.

[0181] To solidify the filament orientation and three-dimensional structure, and to create the thickness / bulkness of the fabric pad, a subsequent step involves unidirectional application of hot air through the pad. The parameter settings for the hot fluid / hot air temperature, penetration velocity, and volume primarily depend on:

[0182] • Total production capacity of the spinning melting box;

[0183] • Fiber size and polymer composition

[0184] Linear velocity

[0185] • The thickness of the padding,

[0186] Fabric basis weight (g / m) 2 ,

[0187] In order to maintain the desired thickness without affecting the parameter settings of the final bonded fabric.

[0188] Since the above process steps can be applied multiple times by adding additional spinning melt boxes with similar or different combinations of polymers, fiber sizes and basis weights, it is preferable to also apply a consolidation step supported by a hot fluid on a common conveyor belt to obtain preliminary product properties before the final bonding step.

[0189] As is evident from the stated definition, manufacturing using spunbond technology involves directly converting a polymer into filaments, which are then randomly spread at the deposition site to produce a nonwoven wadding containing these filaments. The spunbond method determines the properties of the individual filaments and the final nonwoven fabric. The final manufactured nonwoven fabric cannot always be used to determine various properties and conditions of the individual filaments, such as the rheological properties, structural properties, activated crimp, self-crimping level, and shrinkage rate of the polymer, which occur during the various manufacturing steps of the nonwoven fabric. The potential crimp or shrinkage of the nonwoven fabric generally determines its ability to produce a fluffy nonwoven fabric, which is achieved by utilizing the crimp or shrinkage of the individual filaments to increase the thickness of the filament wadding; however, this occurs without disintegrating the fabric structure and / or significantly altering the length and width of the filament wadding. The scope of this invention includes the fact that the crimping / shrinkage of filaments is defined by using various raw materials contained in the filament composition and / or by setting different material processing conditions during the manufacture of filaments for nonwoven fabrics and / or by using different filament cross-sectional shapes / arrangements and / or by adjusting the mass ratio between various input materials and / or by setting different filament orientations.

[0190] The recommended form of the structure of this invention does not distinguish between filaments with a cross-section that supports crimping and filaments with a cross-section that does not support crimping. Both types can be advantageously used in certain applications. Similarly, suitable combinations can be produced by using layers of crimped and non-crimped filaments. It will be apparent to those skilled in the art that there are technical advantages offered by filaments with a cross-section that does not support crimping compared to crimped filaments in obtaining a loose and soft yielding material.

[0191] The method according to the invention may include one or more different bonding steps, see below. Figure 23 For example, a filament pad can be laid on the moving belt and bonded to an bonding unit on one or both sides, the bonding unit being placed directly after the filament is laid from the spinning box.

[0192] For various reasons, a greater distance between the filament spinning box and the bonding unit may be advantageous. Often, more than one spinning box is used to form a layered structure, or for process reasons, the filament pad may need to pass through the gap between the moving belt and the bonding unit. In this case, which is common in spinning melt production lines, pad pre-consolidation is required to increase pad stability so that it can withstand the production process before bonding. Furthermore, for example, potential crimping thermal activation may be required before bonding. Pre-consolidation and / or activation can be performed using rollers (e.g., compact rollers), hot air (e.g., HAK, HAF units), thermal radiation (e.g., infrared pre-consolidation), etc. To further explain, the process is described using a case with three different bonding steps. It should be noted that the layered structure of the present invention can also be formed by production processes with different combinations of pre-consolidation / activation and bonding units.

[0193] For example, one embodiment of the invention also includes the fact that the filament mat is thermally pre-consolidated, meaning it is pre-consolidated and may contain thermally formed adhesives. One advantageous embodiment of the invention is also the fact that the resulting nonwoven fabric is thermally activated to achieve controlled shrinkage and / or crimping of the filaments in at least one layer. Consolidation and possible thermal activation are preferably carried out by at least one action involving contact with a flow of a hot medium (e.g., by hot air or infrared radiation) and / or contact with a hot surface. An example of such a hot surface may be primarily part of a roller. Thermal activation is desired under conditions where the action occurs uniformly across the entire surface of the fiber layer. Thermal activation can be carried out in a chamber in which hot air is supplied, or through a furnace via the filament layer. Thermal activation and consolidation can also be carried out by infrared or ultraviolet light, transmitted microwaves, and / or laser radiation. It should be emphasized that within the scope of the described process “on the manufacturing line,” thermal consolidation can also occur directly after the preceding steps of the manufacturing process are completed, or the two steps of the process, namely thermal activation and consolidation, can be carried out “off the manufacturing line,” i.e., separately from the preceding steps of the manufacturing process. Therefore, thermal activation can be performed essentially "off the manufacturing line" at different times and locations.

[0194] For the solution according to the invention, it is advantageous when the flow of the heat medium passes through the fabric and thus results in heat transfer throughout the entire volume of the nonwoven fabric.

[0195] The required pre-consolidation of filament waddings depends heavily on the conditions of the manufacturing process. A crucial prerequisite is likely the proper setting of the mutual cohesion level of the filaments within the filament batt, and thus, the mutual cohesion level can be controlled based on the requirements of subsequent steps in the manufacturing process. In cases where the manufacturing process takes place on a production line and activation occurs on the conveyor belt itself, the required cohesion is relatively low, as it only needs to prevent disintegration or thinning caused by significant undesirable movement during activation. In special cases, such as when the filaments themselves provide very good cohesion during contact with each other or with their substrate—which can be achieved, for example, by the shape / arrangement of their cross-sections, weaving speed, or their material composition—the cohesive properties of the filament wadding can be sufficiently good even without thermal pre-consolidation. In other cases, such as when the manufacturing process is divided into two steps or when the filament wadding is pre-consolidated before full activation and transferred, for example, in roll form, the required cohesion will be much higher, resulting in a much higher required level of pre-consolidation. Those with technical expertise and a good understanding of manufacturing process conditions will be able to easily determine the level of pre-curing required for their specific situation.

[0196] For example, in the case of controlled shrinkage, the activation temperature should be within the range between the glass transition temperature and the softening temperature of component A (the Vicat softening temperature according to ISO DIN 306). A person skilled in the art will be able to determine the optimal activation temperature for a given component composition.

[0197] Inside the convection cooler, the filaments are typically cooled by a flowing fluid, primarily by cooling air. As mentioned above, the potential shrinkage or crimp of the filaments must be uniformly distributed across the entire length, width, and thickness of the wadding exhibiting the shrinkage. Filament-related properties can be altered by adjusting the draw ratio, cooling air / polymer ratio, and filament speed, and according to the invention, these parameters are virtually identical for each individual filament.

[0198] The scope of this invention includes the fact that the resulting nonwoven fabric is preferably produced by spunbonding in a spinning box. 1 Formation occurs on top. Simultaneously, it is evident that multiple layers can be deposited stacked on top of each other, subsequently forming at least one shaped zone. 2 The previous group was transferred to the institution 3 In the middle, it is used for final consolidation.

[0199] filament 4 Through the spinneret 5The spinning process produces filaments. The arrangement of the filaments can be optimized through their alternating arrangement, which allows for conditions where each individual filament has a very similar weight and is supplied with cooling air at a very similar temperature. The spinnerets can have different numbers of capillaries, and similarly, different diameters (d) and lengths (l) of these capillaries. The length (l) is typically calculated as a multiple of the capillary diameter and is selected in the range of 2 l / d to 10 l / d for this application area. The number of capillaries needs to be selected based on the desired final filament diameter, the desired or planned total polymer processing volume, and the required filament spinning speed. The number of capillaries can vary from 800 to 7000 capillaries per meter, within which filaments with diameters from 8 to 45 μm can be obtained. The capillary diameter and filament speed are selected to achieve the appropriate level of potential shrinkage in the final filament. For filaments with a cross-section that does not support crimping and exhibits a shrinkage rate of 3000 to 5500 m / min, the filament speed should be limited to 1000 to 10000 m / min, and the capillary diameter should be selected to be 200 to 1000 μm, which allows for a suitable process draw ratio of 200 to 1300 in the case of circular capillaries. Although a draw ratio of 300 to 800 is most advantageous in the case of these circular capillaries to achieve the desired level of production rate of the manufacturing line. Generally, non-circular capillaries exhibit higher draw ratio values, which largely depend on the shape of the capillary and the relative ratio of its surface area to volume. The volume and temperature of the cooling air are set in a manner that enables the correct draw ratio and the correct cooling conditions. It has been found that for the present invention, a cooling air volume to spinning polymer ratio of 20:1 to 45:1 is useful. The volume and temperature of the cooling air are controlled in the cooler (6). The temperature can be set from 10°C to 90°C, preferably from 15°C to 80°C, thus allowing the cooling conditions to be used in specific situations to control the shrinkage process. The cooling conditions determine the rate at which the filament cools from the melting temperature to the glass transition temperature during spinning. For example, setting a higher cooling air temperature results in delayed cooling of the filament. In fact, for the purposes of this invention, it is easier to achieve the desired and available cooling air temperature range when the cooler is divided into two zones, where the temperature range can be controlled independently. In the first zone located near the spinneret… 6a In this setting, the temperature can be set from 10°C to 90°C, preferably from 15°C to 80°C, and most preferably from 15°C to 70°C. In the second zone, located directly near the first zone... 6b In this process, the temperature can be set from 10°C to 80°C, preferably from 15°C to 70°C, and most preferably from 15°C to 45°C.

[0200] Subsequently, the filament is guided through the stretching zone. 7Here, the filament is stretched by a tensile force generated by the velocity of the cooling air. Adjustable geometry of the cooling air volume and the stretching zone allows for a specific air velocity, which is then transferred to the filament speed. This filament speed, along with the amount of polymer processed, then defines the filament diameter. Potential shrinkage / tightening is adjusted by the filament speed, draw ratio, and cooling air / polymer ratio.

[0201] In the next step, the filament is fed into the diffuser. 8 diffuser 8 The opposing walls are separated from each other relative to the direction of travel of the filaments. The positions of these walls can be adjusted in a way that allows for the production of nonwoven fabrics with a uniform composition, wherein individually deposited filaments are formed in an omnidirectional arrangement in the MD / CD plane.

[0202] Simultaneously, it is evident that the deposited filament layer is influenced by air, which supplies the filaments to the diffuser. The airflow can be modulated to produce various arrangements, ranging from distinctly serrated filament deposition to truly circular rings, and even further, similarly, elliptical structures oriented in the CD direction. The filaments are deposited on a forming belt and conveyed to at least one mechanism for pre-consolidation. 9 Cooling air flows over the deposited filament layer and through the forming belt, then is guided away from the processing area. The volume of the suction air can be adjusted in such a way that filament deposition is facilitated, and similarly, effective contact between the filament layer and the forming belt is ensured. The pre-consolidation mechanism is located near the diffuser. The formation of the filament layer is controlled by suction air throughout the entire path between the diffuser and the pre-consolidation mechanism. Pre-consolidation of the filament layer is performed using hot air.

[0203] The amount of energy transferred to the filament layer is controlled by methods that allow the filaments to soften or pre-melt only to a certain extent, ensuring good cohesion between the individual filaments. Once the necessary cohesion is achieved between the filaments, the fiber layer can be conveyed to the forming belt without any additional assistance and without being affected or at risk of damage due to the forces generated during this conveying process. This pre-consolidation method is also sufficient to move the filament layer to different deposition areas on a manufacturing line consisting of multiple spinning boxes. The energy transferred to the filaments is insufficient to activate their shrinkage.

[0204] The method according to the invention includes determining a balance between pre-consolidation parameters: pre-consolidation temperature, pre-consolidation air velocity, and pre-consolidation time. Pre-consolidation time should be understood as the time during which the filament layer is modified by the pre-consolidated air.

[0205] The recommended pre-consolidation time for the filament layer is 1ms to 10000ms, preferably 2ms to 1000ms, and most preferably 4ms to 200ms.

[0206] The velocity of the pre-consolidated air used in this pre-consolidation unit is set to 0.1 m / s to 10 m / s, preferably 0.8 m / s to 4 m / s. The recommended consolidation temperature during pre-consolidation is 80°C to 200°C, preferably 100°C to 180°C. In one configuration, the pre-consolidation temperature is 90°C to 150°C, primarily 110°C to 140°C.

[0207] In an advantageous configuration located in the manufacturing line area following the diffuser, the filament pad is conveyed to at least one activation unit. 10 The filaments are activated by hot air. It is understood that the actual crimp or shrinkage rate of the shrinkable component of the filament is a function of temperature, and also a function of the duration of temperature exposure. Furthermore, the speed of the crimp / shrinkage process is clearly also temperature-dependent. This control achieved through this method results in a cohesive and uniform structure in the nonwoven fabric with a reduced filament structure density, which also leads to an increase in the thickness of the nonwoven fabric.

[0208] According to one embodiment of the invention, the execution of the pre-consolidation and activation method steps, during which the pre-consolidation and / or activation time, the air velocity required for pre-consolidation and / or activation, and the pre-consolidation and activation temperature are controlled by a combination method in a combination mechanism for pre-consolidation and activation.

[0209] One advantageous method according to the invention includes determining a balance between activation parameters: activation temperature, activation air velocity, and activation time. Activation time should be understood as the time during which the filament pad is modified by the activation air. Clearly, these parameters can be varied within specific ranges to respond to the potential level of filament shrinkage; similarly, the aim is to establish an ideal combination between activation time, activation temperature, and activation air velocity.

[0210] The recommended activation time for the filament pad is 20ms to 5000ms, preferably 30ms to 3000ms, and most preferably 50ms to 1000ms.

[0211] The velocity of the activation air used in this activation unit is set to 0.1 m / s to 2.5 m / s, preferably 0.3 m / s to 1.5 m / s. The recommended activation temperature during thermal activation is 80°C to 200°C, preferably 100°C to 160°C. In one configuration, the activation temperature is 90°C to 140°C, primarily 110°C to 130°C.

[0212] One embodiment of the invention may include one or more gaps between manufacturing units or processing units. Advantageously, when releasing the initial fabric or wadding from the conveyor belt along the MD web path, the release is performed at the lowest possible initial differential speed between the conveyor belt and the first friction point downstream, so as to maintain the soft surface of the fabric or wadding without altering the overall geometry, particularly the original thickness, and the original tactile properties such as the fabric or wadding surface.

[0213] The final product characteristics can also depend on the tension that needs to be applied in order to release the pre-consolidated pad from the conveyor belt and from each moving surface in the machine direction, which can also be referred to as a friction point.

[0214] In particular, the release tension of the wadding from the conveyor belt may be crucial.

[0215] Controlled tension is often described as the force per linear fabric dimension and its extension across its width, but for defined and controlled parameter settings, there is a generally accepted way to “interpret” tension by the difference in speed between two downstream adjacent friction points.

[0216] Because it mainly depends on the fabric weight, linear speed, and surface friction between the fabric and the support surface, differential setting is a direct way to adjust the speed of the actively driven surface.

[0217] For example, the method according to the invention may include: the differential speed between the conveyor belt and the air intake roller of the air-passing bonding unit must be less than 1.0%; more preferably less than 0.5%, and even more preferably less than 0.3%. A differential speed of less than 1.0% means that the speed of the second device can be in the range of +1.0% to -1.0%.

[0218] According to one embodiment of the invention, a conveyor belt (2) is included, and the process is carried out under the following conditions: before the nonwoven wadding is transferred from the pre-consolidation step to the consolidation unit (3), the fabric strength of the nonwoven wadding in the machine direction (MD) is 0.5 to 5 N / 5 cm, preferably 0.7 to 3.5 N / 5 cm, more preferably 0.8 to 3.5 N / 5 cm.

[0219] Other embodiments of the invention include a conveyor belt (2) and are carried out under the condition that the nonwoven wadding has a fabric strength in the machine direction (MD) of more than 6 N / 5 cm, preferably more than 8 N / 5 cm, and more preferably more than 10 N / 5 cm before the nonwoven wadding is transferred from the pre-consolidation step to the consolidation unit (3).

[0220] One embodiment of the invention includes intermediate cooling between the pre-consolidation step and the final consolidation step. For example, the nonwoven mat may be exposed to a cooling medium along its path, preferably air at a temperature equal to or below 70°C, more preferably equal to or below 60°C, and most preferably equal to or below 55°C. For example, intermediate cooling can be performed by exposing the pre-consolidated mat to ambient air. Without being bound by theory, we believe that intermediate cooling, in particular, in which at least one surface of the nonwoven fabric is heated during pre-consolidation, exposed to a lower temperature, and then heated again during the consolidation step, is advantageous for the formation of denser outer layers.

[0221] An advantageous configuration according to the invention includes a final consolidation process comprising altering the filament mat using hot air in a consolidation mechanism (3). Inside this consolidation mechanism, the filament mat is consolidated into a fabric having formed filament-to-filament bonds. This can be achieved by a variety of devices, including, for example, consolidation mechanisms with bell-shaped rollers, consolidation mechanisms with flat belts, or multi-roller consolidation mechanisms.

[0222] It should be noted that thermoplastic polymers and their blends are characterized by a gradually increasing plastic softening state (reduced viscosity) above their glass transition point (when all amorphous portions begin to soften) and below their melting point (when all crystalline portions melt). The melting point is typically within a very narrow temperature range (maximum 2.0°C) and is defined by the homopolymer or copolymer used. In the case of polymer blends, a narrow temperature range can be determined when the polymer blend becomes viscous and is able to form filament-to-filament bonds.

[0223] An advantageous configuration according to the invention involves using at least three distinct consolidation sections to perform the final consolidation process. Essentially, the airflow is substantially perpendicular to the fabric and maintains a uniform temperature and low-variation volumetric flow rate.

[0224] The first consolidation section preheats the fabric to a temperature close to or below the melting point of the bonding polymer. Preferably, the temperature is set 5-20°C lower than the melting point of the bonding polymer; more preferably, the temperature is set 5-15°C lower; advantageously, the temperature is set 5-10°C lower. Advantageously, the first consolidation section includes alternating heat flow directions from the first and second outer surfaces of the fabric.

[0225] The second consolidation zone is configured to achieve a narrow melting temperature window for the low-temperature melting polymer composition to allow for fusion bonding. On the other hand, the set temperature relative to the fabric's basis weight, fiber size, and cross-sectional ratio between the component polymers should be in the range of no more than 5.0°C lower and no more than 3.0°C higher than the melting temperature of the bonding polymer. For example, when the melting point is 130°C, the set temperature should be in the range of 125°C (130-5) to 133°C (130+3). Preferably, the temperature is set in the range of 5°C lower than to equal to the melting temperature of the bonding polymer; more preferably, the temperature is set in the range of 4°C to 1°C lower than the melting point of the bonding polymer. Advantageously, the second consolidation zone includes alternating heat flow directions from the first and second outer surfaces of the fabric.

[0226] The third consolidation section is a cooling section, providing cooler air, preferably at a temperature of 10-40°C, more preferably 20-30°C. Ambient air can be used. The cooling section helps to solidify the filaments on the fabric surface, or at least the filaments on the fabric surface, and solidifies the layered structure formed by the fabric. Advantageously, no additional tension is applied directly before and during the cooling process. Advantageously, another cooling step can be applied after the consolidation unit. Further cooling can be provided by further airflow, cooling rollers, etc. Advantageously, further cooling is performed when the temperature of the fabric leaving the third consolidation section has not reached ambient temperature. Advantageously, the fabric will reach ambient temperature, preferably 40-10°C, and even more preferably 20-30°C. For advantageous economic reasons, the method produces fluffy, soft, and low-pilling nonwoven fabrics with high throughput and high production speed.

[0227] For example, in one embodiment of the invention, a 4-roller hot air through-feed consolidation device can be used. This device allows for short residence times even at high speeds, while also ensuring sufficient exposure to the necessary hot air flow and volume along the maximum mesh width path to achieve the necessary low-viscosity melt flow, thereby producing fusion bonding within a defined narrow parameter window. The rollers in the machine direction allow a contact angle of at least 100°, preferably at least 130°, more preferably at least 150°, and advantageously at least 160°.

[0228] The precise parameter setting window for the selected device depends on the chosen bonding polymer and the mass ratio between the filament size, filament cross-section, and polymer component formulation.

[0229] The 4-roller assembly also enables a strong, alternating, substantially vertical flow of hot air through the substrate for a short period. The first pair of rollers is configured to preheat the fabric structure to just below the softening and melting points of the low-melting-point polymer composition. A second pair of rollers is configured to achieve the melting temperature window of the low-melting-point polymer composition, thereby allowing for fusion bonding. To maintain the fabric structure and preserve the integrity of the fusion bond, the final roller includes heating and cooling sections along its circumference in the machine direction. Advantageously, the fabric structure is cured, or at least the surface of the fabric structure is cured before it is released from the bonding device. A separate, additional cooling roller with a high flow rate of cooling air through the fabric is located at the shortest possible distance from the last roller of the air-through bonding device, which ultimately completes the curing of the fabric through immediate cooling.

[0230] The consolidated nonwoven fabric is wound onto a reel (11) in the final stage. In cases where it is necessary to change the surface properties of the nonwoven fabric, such as to achieve improved fluid transport or increase the ability to discharge them, a spraying mechanism or impregnation roller is located between the moving belt and the final consolidation mechanism, or between the final consolidation mechanism and the reel.

[0231] One embodiment of the invention includes combining activation and consolidation steps, wherein the activation time and / or consolidation time, the air velocity required for activation and / or consolidation, and the activation and / or consolidation temperature are controlled within the consolidation mechanism.

[0232] A key element is determining the balance between the following consolidation parameters: consolidation temperature, consolidation air velocity, and consolidation time. Consolidation time should be understood as the time it takes for the filament mat to be altered by the consolidation air. Clearly, these parameters can be varied within specific ranges to respond to the potential consolidation level of the filament mat, and similarly, the aim is to achieve an ideal combination of consolidation time, consolidation temperature, and consolidation air velocity.

[0233] The recommended consolidation time for long-filament wadding is 200 to 20000 ms, preferably 200 to 15000 ms, and most preferably 200 to 10000 ms.

[0234] The velocity of the consolidation air used in this consolidation unit is set to 0.2 to 4.0 m / s, preferably 0.4 to 1.8 m / s. The recommended consolidation temperature during thermal consolidation is 100°C to 250°C, preferably 120°C to 220°C. In one configuration, the consolidation temperature is 90°C to 140°C, primarily 110°C to 130°C.

[0235] Example

[0236] Further details and specific features of the invention will be explained based on embodiments. These embodiments illustrate practice of the invention but are not intended to be considered as limiting the invention. Other embodiments and modifications within the scope of the claimed invention will be apparent to those skilled in the art. Therefore, the scope of the invention will be defined by the appended claims.

[0237] Example usage The R5 type spinning-melting production line provided by Reicofil GmbH & Co. KG produces the bicomponent filaments. The production line comprises two spunbonding boxes (A, D), each suitable for producing bicomponent filaments. In Example 1, only one spunbonding box is used; in Examples 2 through 13, two boxes are used. Filaments from the first box are laid on a moving belt to form a first layer, and filaments from the second box are laid on the first layer to form a second layer of fusible mat. After each box, the fusible mat is pre-bonded using hot air; thus, after the first box, one layer is pre-bonded, and after the second box, two layers are pre-bonded together. The resulting bicomponent fusible mat is moved to an air-through bonding unit comprising four rollers. The fusible mat is air-bonded from the first side through the first roller, then from the second side through the second roller, then again from the first side through the third roller, and finally from the second side through the fourth roller. The first two rollers constitute a first bonding section, and portions of the third and fourth rollers constitute a second bonding section. Cooling of the nonwoven fabric begins in the fourth roller (third consolidation section), where most of its contact surface is used for the final stage of air-through bonding with hot air (second consolidation section), and the last portion corresponding to 30° of the roller contact surface is used as the first stage of cooling the fabric, i.e., as the air-through cooling stage (i.e., the last surface in direct contact with the nonwoven fabric before it leaves the air-through bonding unit is used for the initial cooling of the fabric). The resulting nonwoven fabric is further cooled by air immediately after leaving the air-through bonding unit. Specific features of the production embodiments are defined below, and the features of the resulting embodiments are indicated in the table below.

[0238] Example 1 - The Invention

[0239] The first box produces filament mats, each filament having a core / sheath structure (non-curling cross-section), wherein the core forms 70% by weight of the filament and contains polyethylene terephthalate (type 5520 from Invista), and the sheath forms 30% by weight of the filament and contains polyethylene (Aspun 6834 from Dow Chemicals).

[0240] Close the second box.

[0241] The first box has a production capacity of 220 kg / hour / meter and a width of the first box.

[0242] For the first and second rollers, the air-through bonding unit is set to 121°C. For the third and most parts of the fourth roller, the air-through bonding unit is set to 127°C. The last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air with a temperature of 24°C.

[0243] The resulting nonwoven fabric has a density of 75 gsm, and its layered structure is well-identifiable in its cross-section (as shown in Figure xx). The denser layers A and C form the outer surface of the fabric, while the very fluffy layer B, with a cavity in the middle, provides the fabric with bulkiness. It should be noted that the layers may or may not form uniformly. For example, here, layer A is much thicker than layer C; see [reference needed]. Figure 24 .

[0244]

[0245]

[0246]

[0247] Example 2 - The Invention

[0248] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein the core-forming filament comprises 40% by weight of a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the sheath-forming filament comprises 60% by weight of a polyethylene blend (Aspun 6850 from Dow Chemicals).

[0249] The second box produces a second layer of filament with a side / side structure, wherein each side forms 50% by weight of the filament. One side contains a polypropylene blend (type 3155 from Exxonmobil, type HG475FB from Borealis, white colorant TiO2 and erucamide), and the second side contains polyethylene (ASPUN 6834 from Dow Chemicals).

[0250] The first box has a production capacity of 160 kg / hour / meter and a width of 1 box. The second box has a production capacity of 240 kg / hour / meter and a width of 2 boxes.

[0251] For the first and second rollers, the air-through bonding unit is set to 125°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0252] The resulting nonwoven fabric had a density of 25 gsm, and its layered structure was well-identifiable. The layered structure was determined using three different methods:

[0253] 1) Perform SEM microscopy on the cross-section. Outer layer A, outer layer C, and inner layer B are easily identified. Because SEM microscopy provides a view "inside" the fabric, determining the interlocking, bonding, or measuring cavities of filaments can be very complex.

[0254] ( Figure 25 ).

[0255] 2) The nonwoven fabric is fixed in the resin and a cross-section is prepared. We now only see the cross-section, where the filaments (which are randomly oriented at this micrometer scale) are treated as black dots. It is evident that the filaments (dots) are denser in layers A and C, and form cavities in the inner layer B. Figure 26 )

[0256] 3) Analyze nonwoven fabrics using X-ray tomography to improve the spatial resolution of the fabric / filament in X-ray images, and metallize the samples in the same way as SEM microscopy. Create a 3D model of the fabric on a computer. Figure 27 ), and then digitally cut into two-dimensional fabric cross-sections ( Figure 28 Metallized filaments are shown as white dots (the size of the white area may be affected by the amount of metal on the filament surface). Regions with filaments closer together (denser regions) can also be represented by white areas. Layers A and C, as well as inner layer B, are clearly visible here.

[0257] All three methods revealed a clearly formed delamination structure in the samples. Different views of different portions of the fabric samples also showed that inner delamination B could form closer to one fabric surface, in the middle, or closer to another fabric surface. Clearly (especially in SEM images), inner delamination does not necessarily form at layer / layer boundaries. Similarly, the fabric properties shown in Table XX demonstrate a good combination of durability and softness in the samples.

[0258] Examples 3 to 5 - The Invention

[0259] Examples 3, 4, and 5 are almost identical to Example 2. They differ in basis weight and filament thickness (given by different devices before filament laying). The bonding process setup is also the same as in Example 2. The layered structure is well identifiable (fabric cross-section shown in Figure xx). Fabric properties are shown in Table xx.

[0260]

[0261]

[0262]

[0263] Example 6 – The Invention

[0264] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein the core forms 40% by weight of the filament and contains a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the sheath forms 60% by weight of the filament and contains polyethylene (Aspun 6850 from Dow Chemicals).

[0265] The second box produces a second layer of filament with a side / side structure, wherein each side forms 50% by weight of the filament. One side contains a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, with TiO2 as a white colorant), and the second side contains polyethylene (Aspun 6834 from Dow Chemicals).

[0266] The production rate of the first box is 120 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0267] For the first and second rollers, the air-through bonding unit is set to 124°C; for most of the third and fourth rollers, the air-through bonding unit is set to 128°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0268] The resulting nonwoven fabric has a density of 25 gsm and the layer structure is well identifiable.

[0269] Example 7 – The Invention

[0270] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein the core-forming filament comprises 40% by weight of a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the sheath-forming filament comprises 60% by weight of a polyethylene blend (Aspun 6850 from Dow Chemicals).

[0271] The second box produces a second layer of filaments with a side / side structure, wherein the first side forms 75% by weight of the filaments. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 25% by weight of the filaments, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0272] The production rate of the first box is 220 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0273] For the first and second rollers, the air-through bonding unit is set to 117°C; for most of the third and fourth rollers, the air-through bonding unit is set to 123°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0274] The resulting nonwoven fabric has a strength of 55 gsm and a well-identifiable layer structure.

[0275] Example 8 – The Invention

[0276] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein the core-forming filament comprises 40% by weight of a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the sheath-forming filament comprises 60% by weight of a polyethylene blend (Aspun 6850 from Dow Chemicals).

[0277] The second box produces a second layer of filaments with a side / side structure, wherein the first side forms 50% by weight of the filament. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filament, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0278] The production rate of the first box is 120 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0279] For the first and second rollers, the air-through bonding unit is set to 125°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0280] The resulting nonwoven fabric has a density of 25 gsm and the layer structure is well identifiable.

[0281] Example 9 – The Invention

[0282] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 50% by weight of the core forming filament comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and 50% by weight of the sheath forming filament comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0283] The second box produces a second layer of filaments with a side / side structure, wherein the first side forms 50% by weight of the filament. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filament, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0284] The production rate of the first box is 160 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0285] For the first and second rollers, the air-through bonding unit is set to 124°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0286] The resulting nonwoven fabric has a density of 22 gsm and the layer structure is well identifiable.

[0287] Example 10 – The Invention

[0288] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 50% by weight of the core forming filament comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and 50% by weight of the sheath forming filament comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0289] The second box produces a second layer of filaments with a side / side structure, wherein the first side forms 50% by weight of the filament. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filament, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0290] The production rate of the first box is 200 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0291] For the first and second rollers, the air-through bonding unit is set to 124°C. For most of the third and fourth rollers, the air-through bonding unit is set to 131°C. The last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) has been set to use ambient air at a temperature of 24°C. A cooling unit is arranged on the MD close to the cooling unit.

[0292] The resulting nonwoven fabric has a density of 65 gsm and the layer structure is well identifiable.

[0293]

[0294]

[0295]

[0296] It should be noted that Examples 9 and 10 can be used in many applications considered to have insufficient adhesion because they have lower tensile and bond strengths. However, even here, a layered structure is formed that provides greater durability on the outer fabric surface.

[0297] The above multilayer embodiments use a combination of eC / S and S / S filaments. It should be noted that even if such a combination may offer advantages, it is not important to the present invention. Example 11 below shows a two-layer fabric, where both layers are formed from filaments having an eC / S cross-section.

[0298] Example 11 – The Invention

[0299] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 60% by weight of the core-forming filaments comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and 40% by weight of the sheath-forming filaments comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0300] The second box produces a second layer of filaments with an eccentric core / sheath structure, wherein the core forms 50% by weight of the filaments. The core comprises a polypropylene blend (type 3155 from Exxonmobil, type HG475 FB from Borealis, white colorant TiO2 and erucamide), and the sheath formed from 50% by weight of the filaments comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0301] The production rate of the first box is 120 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0302] For the first and second rollers, the air-through bonding unit is set to 124°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling unit is arranged on the MD after the bonding unit.

[0303] The resulting nonwoven fabric has a density of 25 gsm and the layer structure is well identifiable.

[0304]

[0305]

[0306] Example 12 – The Invention

[0307] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 50% by weight of the core forming filaments comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and 50% by weight of the sheath forming filaments comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0308] The second box produces a second layer of filaments with a side / side structure, wherein the core forming 50% by weight of the filaments. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filaments, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0309] The production rate of the first box is 160 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0310] For the first and second rollers, the air-through bonding unit is set to 120°C; for most of the third and fourth rollers, the air-through bonding unit is set to 128°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 24°C; and a cooling area is arranged on the MD after the bonding unit.

[0311] The resulting nonwoven fabric has a density of 35 gsm and the layer structure is well identifiable.

[0312] Example 13 – The Invention

[0313] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 40% by weight of the core-forming filaments contain a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and 60% by weight of the sheath-forming filaments contain polyethylene (Aspun 6850 from Dow Chemicals).

[0314] The second box produces a second layer of filaments with a side / side structure, wherein the core forming 50% by weight of the filaments. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filaments, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0315] The production rate of the first box is 120 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0316] For the first and second rollers, the air-through bonding unit is set to 123°C; for most of the third and fourth rollers, the air-through bonding unit is set to 128°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 19°C; and a cooling area is arranged on the MD after the bonding unit.

[0317] The resulting nonwoven fabric has a density of 25 gsm and the layer structure is well identifiable.

[0318] Example 14 – The Invention

[0319] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 50% by weight of the core forming filaments comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and 50% by weight of the sheath forming filaments comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0320] The second box produces a second layer of filaments with a side / side structure, wherein the core forming 50% by weight of the filaments. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filaments, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0321] The production rate of the first box is 140 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0322] For the first and second rollers, the air-through bonding unit is set to 124°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 21°C; and a cooling area is arranged on the MD after the bonding unit.

[0323] The resulting nonwoven fabric has a density of 20 gsm and the layer structure is well identifiable.

[0324] Example 15 – The Invention

[0325] The first box produces a first layer of filaments with an eccentric core / sheath structure, wherein 50% by weight of the core forming filaments comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and 50% by weight of the sheath forming filaments comprises polyethylene (Aspun 6850 from Dow Chemicals).

[0326] The second box produces a second layer of filaments with a side / side structure, wherein the core forms 50% by weight of the filaments. The first side comprises a polypropylene blend (type 3155 from Exxonmobil, type HG712 FB from Borealis, white colorant TiO2 and erucamide), and the second side, formed from 50% by weight of the filaments, comprises polyethylene (Aspun 6834 from Dow Chemicals).

[0327] The production rate of the first box is 140 kg / hour / meter in width, and the production rate of the second box is 240 kg / hour / meter in width.

[0328] For the first and second rollers, the air-through bonding unit is set to 124°C; for most of the third and fourth rollers, the air-through bonding unit is set to 129°C; the last part of the fourth roller (the last part corresponds to 30° of the contact surface of the roller) is set to use ambient air at a temperature of 18°C; and a cooling unit is arranged on the MD after the bonding unit.

[0329] The resulting nonwoven fabric has a density of 18 gsm and the layer structure is well identifiable.

[0330]

[0331]

[0332]

[0333] I. Testing Methods

[0334] The "basis weight" of the nonwoven fabric was measured using the test method according to standard EN ISO 9073-1:1989 (corresponding to method WSP 130.1). For the measurement, 10 layers of nonwoven fabric were used, and the sample size was 10 x 10 cm. 2 .

[0335] The tensile strength and elongation of nonwoven fabrics were measured using the test method according to WSP 110.4.R4(12) standard.

[0336] The “thickness” or “measurement height” of nonwoven materials is determined by the test measurement method according to European standard EN ISO 9073-2:1995 (corresponding to method WSP 120.6), modified as follows:

[0337] 1. The material is measured by using a sample taken from the manufacturing process, which is not subjected to high deformation forces or pressure for more than one day (e.g., by pressure applied to the manufacturing equipment by rollers), but the material must be left to rest freely on a surface for at least 24 hours.

[0338] 2. The total weight of the top arm of the measuring machine, including the additional ballast, is 130g.

[0339] The "bulkness," "loft," or "density" of nonwoven fabrics is expressed in kg / m³. 3 By "basic weight" (g / m 2 Divide by the thickness (mm) to calculate.

[0340] The thickness-to-basic weight ratio of nonwoven fabrics is expressed as dm 3 / kg or l (liter) / kg and calculate "thickness" (mm*1000) divided by "basic weight" (g / m 2 ).

[0341] The stiffness of nonwoven textiles, expressed by the measurement “Handle-O-Meter” (HOM), is determined according to international standard WSP 90.3. Unless otherwise specified for the measurement, the sample size is 100 × 10 mm. HOM is measured separately in the MD and CD directions. Unless the MD or CD direction is specified, the arithmetic mean of these two values ​​is used.

[0342] In this document, the term "regeneration" or "recovery" of bulkiness refers to the ratio between the thickness of the fabric after the load is released and the initial thickness of the fabric. The fabric thickness is measured according to EN ISO 9073-2:1995, using an initial load equivalent to 0.5 kPa pressure.

[0343] The procedure for measuring regeneration consists of the following steps:

[0344] 1. Preparation of a 10x10cm fabric sample

[0345] 2. Measure the thickness of a piece of fabric.

[0346] 3. The thickness (Ts) of five fabric pieces stacked on top of each other was measured using an initial load equivalent to 0.5 kPa pressure.

[0347] 4. Apply a load (at a pressure of 2.5 kPa) to five stacked fabric pieces on a thickness measuring device for 5 minutes.

[0348] 5. Release the device and wait 5 minutes.

[0349] 6. Measure the thickness (Tr) of five pieces of fabric stacked together using an initial load equivalent to 0.5 kPa pressure.

[0350] 7. Calculate regeneration based on the following equation:

[0351] Regeneration = Tr / Ts (unitless)

[0352] Ts = Thickness of the freshly prepared sample

[0353] Tr = Thickness of the regenerated sample

[0354] The term "compressibility" here refers to the distance, in millimeters, that a nonwoven fabric can be compressed by a load defined during the "flexibility" measurement. It can also be calculated as the product of resilience (unitless) and thickness (mm). The "elasticity" or "resilience" of a nonwoven fabric is measured using the test method according to standard EN ISO 964-1, modified as follows:

[0355] 1. Measure the thickness of a fabric layer.

[0356] 2. Prepare several fabric samples such that their total thickness after being stacked on top of each other is at least 4 mm, ideally 5 mm. Each stacked fabric assembly contains at least one piece of fabric.

[0357] 3. Measure the thickness of these stacked fabric samples.

[0358] 4. A force of 5 N is permissible to be applied to the stacked fabric samples at a load velocity of 5 mm / min.

[0359] 5. Measure the distance corresponding to the movement of the clamping element.

[0360] 6. Calculate the resilience based on this equation:

[0361] R (unitless) = T1 (mm) / T0 (mm)

[0362] or

[0363] R (%) = T1 (mm) / T0 (mm) * 100%

[0364] T1 = The distance [mm] corresponding to the movement of the clamping element under a load of 5N = The degree of compression of the stacked fabric.

[0365] T0 = ​​Thickness (according to standard EN ISO 9073-2:1995, with an initial load of 1.06 N) [mm]

[0366] "Martindale Average Abrasion Rating Test" or "Martindale"

[0367] Figure 38 This is a perspective view of the equipment used for Martindale average abrasion rating testing. Figure 39 The napping assessment in the Martindale average abrasion rating test described herein is as described in Procter & Gamble's published patent application US20200170853A1.

[0368] The average abrasion resistance of nonwoven fabrics was measured using a Martindale abrasion tester. The fabric was dried before testing.

[0369] • Condition the nonwoven sample at 23±2℃ and 50±2% relative humidity for 24 hours.

[0370] • Cut a circular sample with a diameter of 162 mm (6.375 inches) from each nonwoven sample. Cut a standard felt into a circle with a diameter of 140 mm.

[0371] • Each sample is secured to its position on each Martindale test grinding table by first placing the cut felt, then placing the cut nonwoven sample. The clamping rings are then secured, so no wrinkles are visible on the nonwoven sample.

[0372] • Assemble the abrasive holder. The abrasive is 38mm diameter, FDA-compliant, 1 / 32-inch thick silicone rubber (from McMaster Carr, Project 86045K21-50A). Place the required weight in the abrasive holder to apply 9 kPa pressure to the sample. Place the assembled abrasive holder in the #864 model so that the abrasive contacts the NW sample as indicated in the operator's guide.

[0373] • Operate Martindale wear under the following conditions:

[0374] ○ Mode: Wear Test

[0375] ○ Rate: 47.5 cycles / minute; and

[0376] ○ Loop: 16 loops

[0377] • After the test is stopped, place the abraded nonwoven fabric on a smooth, matte, black surface and use... Figure 14 The provided scale grades the napping level. Each sample is evaluated by observing from the top to determine the size and number of defects, and by observing from the side to determine the loft height of the defects. A number from 1 to 5 is assigned based on the best match with the grading scale. The Martindale average abrasion rating is then calculated as the average rating of all samples and reported as the closest tenth.

[0378] "Delamination strength" or "bonding" can be determined by the following methods (see...). Figure 40 and 41 ):

[0379] 1) Cut a sample with a length (MD direction) of 120 mm and a width of at least 30 mm.

[0380] 2) Cut two 145mm long strips of material, and fold the last 25mm of each strip on one side. Reinforce the sample with a 25.4mm wide strip, then bond it by rolling it once in one direction with a 7kg hand roller. Cut the sample along the strip into 25mm CD widths. Separate the free ends of the strips.

[0381] 3) The tensile strength testing machine has the following characteristics: two jaws with clamping surfaces on the same plane parallel to the direction of movement of the applied stress. They must be aligned so that they hold the specimen within this plane throughout the test without slipping or damaging the sample. The four sides of the jaws should be filled with a thin strip of soft-waisted rubber to prevent slippage and damage to the test specimen. Thwing Albert, Instron, Zwick, or equivalent machines can be used for constant-rate transverse tensile testing according to ASTM D 76-99.

[0382] 4) Set the parameters as follows:

[0383] a) Gauge length......................................50mm

[0384] b) Crosshead speed....................................305mm / min

[0385] c) Pre-tension length..................................10mm

[0386] d) Measured length…....................................152mm

[0387] e) Sample scanning frequency..................................50Hz

[0388] 5) When properly positioned in the upper fixture, place the sample onto the testing machine by clamping the free end of the strip. Figure 41 Return the free end of the strip and clamp it in the lower fixture. Align the free end of the sample symmetrically in the fixture to ensure even tension distribution. Adjust the load range as needed so that the reading is between 30% and 80% of the full load range.

[0389] 6) Start the tensile testing machine.

[0390] 7) Measure 10 samples and calculate the average value.

[0391] 8) Report the average separation force, retaining it to 0.01N.

[0392] The type of fiber cross-section is known from the process conditions defined by the fiber forming die. When the process conditions are unknown, the following estimation can be used:

[0393] Take a sample of the fabric and photograph the cross-sections of at least 20 fibers. Measure the cross-sections on the free portion of the fibers, not at bonded points where deformation is expected or at locations in contact with another fiber. For each cross-section, mark the surface of each component on the image. Determine the centroid or geometric center of each component based on the determination of the centroid or geometric center of the planar object, and record its position using a Cartesian coordinate system with the center [0; 0] at the geometric center of the fiber cross-section. Calculate the offset (D) of the centroid of each component in each fiber cross-section according to the following equation:

[0394] D = absolute value(x*y), where x and y are the coordinates of the centroid. A sample is discarded from the evaluation if either x or y is 0 while the other is not.

[0395] Calculate the mean and standard deviation for each component.

[0396] A fiber is considered non-curlable when the ratio of (mean offset plus standard deviation) to the total cross-sectional surface area of ​​the fiber is less than 5%.

[0397] When the ratio of (mean offset) minus (standard deviation) to the total fiber cross-sectional surface area is less than 10%, the fiber is expected to be non-curlable.

[0398] "Filament bonding density", "filament density", "cavity length and height" and "cavity percentage in the thickness of the nonwoven fabric" can be determined from the cross-section of the fabric.

[0399] At least 10 samples were taken from the MD and 10 samples from the CD. The fabric was considered to have a layered structure present in at least 50% of the samples, and this layered structure was identified.

[0400] The material will be measured using samples taken from manufacturing, without being subjected to high deformation forces or pressure for more than a day (e.g., pressure applied by rollers on manufacturing equipment), otherwise the material must remain freely laid on the surface for at least 24 hours.

[0401] Cross sections can be prepared and analyzed using several methods:

[0402] Methods for making fabric cross-sections

[0403] 1) Simple cross-section:

[0404] Place the fabric on a suitable table and cut it with a sharp razor blade. Check the cut to ensure it has approximately the same thickness as the fabric (e.g., the filaments are not compressed or "cut-bonded" together).

[0405] 2) Resin cross-section:

[0406] Place the fabric sample in a container and pour in the liquid resin, allowing it to cure. The resin needs to be selected such that it easily fills all the void volumes in the fabric in liquid form and can be easily distinguished from the fabric polymer in solid form.

[0407] The solid resin block was cut in half to make a cross-section of the fabric sample.

[0408] 3) Digital cross-section:

[0409] The sample is scanned (e.g., computed tomography, micro-CT) and a digital cross-section is created in a computer.

[0410] Methods for cross-sectional analysis of samples:

[0411] 1) SEM microscopy

[0412] a) If necessary, place the filament sample in a suitable holder (e.g., see [reference]). Figure 42A and Figure 42B And conduct analysis.

[0413] b) Metallize the sample with gold (e.g., using an Au / Pd metallization device, SC 7640 sputtering coating machine).

[0414] c) Analyze the sample using an electron microscope (e.g., Tescan, using a BSE detector) at 30 kV and an appropriate magnification (30 x – 1000 x).

[0415] 2) 3D Tomography

[0416] a) If necessary, coat the sample with a thin layer of contrast material. For example, polyolefins are not well visible when using 3D X-ray computed tomography (Skyscan). For example, the sample can be metallized with gold (e.g., using an Au / Pd metallization equipment SC7640 sputtering coater).

[0417] b) Place the sample in the analysis chamber and scan.

[0418] 3) 3D μCT - See "Methods for determining the geometric fiber statistics of nonwovens"

[0419] All of the above methods and analyses (except 3D μCT) can be applied, for example, at the University of Zlín-Tomas Bata in the Czech Republic. The Bat'a in Zlín (CZ) Technical College was established.

[0420] Then analyze the obtained cross-sectional images:

[0421] 1) "Filament bonding density", "Filament density"

[0422] a) The fabric cross-section is divided into regular segments, each segment representing a maximum thickness of 0.05 mm (e.g., a 0.45 mm thick fabric is divided into 9 segments of 0.05 mm thickness).

[0423] b) Each segment has a length of at least 0.5 mm, preferably the length visible in a cross-sectional image.

[0424] c) Setting density

[0425] i) Calculate the number of interfilament bonds in each segment and express it as the interfilament bond density (number of bonds / segment area); or

[0426] ii) The area occupied by the filaments in each segment is calculated and expressed as filament density (area occupied by filaments / area of ​​segment).

[0427] d) Adjacent segments providing the same or very similar density can be combined to form a stratification.

[0428] e) Specify strata A, strata B, and possible strata C, and calculate their average values.

[0429] f) Calculate the value of the ratio

[0430] 2) "Length and height of the cavity" and "Percentage of the cavity in the nonwoven fabric thickness"

[0431] a) Take the aforementioned hierarchical structure and further study the region of hierarchical B.

[0432] b) The void volume area is highlighted.

[0433] c) Cavities are identified as cavities if the area within the fabric thickness (in the z-direction of the fabric) is greater than 3 times the average filament thickness and its length (in the MD×CD plane of the fabric) is greater than 5 times the average filament thickness.

[0434] d) Calculate the area of ​​all cavities and express it as a percentage of the area of ​​layer B.

[0435] e) Measure each cavity in the height = fabric thickness direction and its length = fabric MD × CD plane direction, and use the maximum value to calculate the L:H ratio.

[0436] "Statistical Methods for Determining the Geometric Fibers of Nonwoven Fabrics"

[0437] Below, we describe a software-based method for analyzing nonwoven material samples to characterize their geometric properties. This method uses machine learning to identify individual fibers present in the sample, followed by geometric analysis of these fibers to obtain statistical data suitable for characterizing the material. Results include fiber orientation and density distribution. This analytical workflow was developed by Math2Market GmbH, as part of the GeoDict digital materials laboratory.

[0438] Step 1: Obtain the three-dimensional μCT image of the sample.

[0439] First, the nonwoven sample is digitized using a μCT scanner to obtain 3D images. The 3D images consist of a uniform Cartesian grid, where each grid cell (volume element: voxel) stores the X-ray attenuation of the sample at its corresponding location. The pore space typically exhibits the lowest attenuation (minimum gray level value), while the material phase exhibits larger values, depending on the material and the configuration of the μCT device.

[0440] Step 2: Separate the material from the pore space using μCT images.

[0441] For further analysis, noise filtering of the grayscale images was performed using a nonlocal means method [1]. Then, the images were binarized using a global threshold derived with the Otsu algorithm [2]. Binarization classified each image voxel into either pore space or fibrous material. Voxels with gray values ​​below the threshold were classified as pore space. All other voxels were classified as fibrous material. For both noise filtering and thresholding, the ImportGeo module of the GeoDict software was used.

[0442] Step 3: Analyze the material density distribution

[0443] Furthermore, the material density distribution along the z-direction was calculated. For each slice of the image (at a given depth Z), the material density was calculated as the number of white material voxels divided by the total number of voxels in the slice. This analysis was performed using the MatDict module of GeoDict.

[0444] Step 4: Apply neural networks to identify fiber centerlines

[0445] The main challenge in identifying single fibers in μCT images is that, after binarization, the fibers are not spatially separated at the contact point. This can lead to undersegmentation, where multiple objects (fibers) are incorrectly classified as single fibers.

[0446] To separate fibers, Math2Market GmbH has developed a method for identifying the centerline curves of fibers. These centerlines are represented in a binary voxel image of the same size as the original image. In this image, voxels within approximately one to two voxels at the center of the fiber are marked.

[0447] For this purpose, we have used a semantic segmentation method employing neural networks [3]. The image is analyzed by considering a 3D sliding input window that moves across the image. For each input window, a smaller output window is defined centered on the input window. The neural network analyzes the binary voxel values ​​in the input window and generates a prediction for each voxel in the output window. The predicted value determines whether the voxel in the output window is part of the center line. By combining the results of all these output windows, we obtain a binary image that classifies each material voxel in the original image. This image transformation is implemented using Tensorflow by the FiberFind-AI module in GeoDict [4].

[0448] Step 5: Create training data for the neural network

[0449] To train the neural network to achieve the aforementioned transformation, Math2Market GmbH has created several artificial 3D images of nonwoven materials using the random FiberGeo structure generation module in GeoDict. This module generates an analytical geometric representation of fibers as a series of line segments. Simultaneously, it outputs a binary image of the fiber structure, equivalent to the binary transformation result from step 2.

[0450] By modifying the fiber diameter in the analysis specimen to approximately 2 to 3 voxels, we can also obtain an image corresponding to the centerline of the artificial fiber structure.

[0451] These image pairs (fibers and centerlines) are then used to train a neural network to transform fiber images into centerline images. The network effectively learns to "shrink" the fibers to their centerline curves.

[0452] Step 6: Tracking fiber centerline to obtain the geometric representation of the fiber

[0453] After reducing the fibers to their centerlines, we assume the centerlines do not touch. Then, assuming each component corresponds to the centerline of a single fiber, we separate the individual centerlines from each other by analyzing the connected components of the centerline image. Connected components are defined as subsets of material voxels that all have the same color and cannot be magnified by adding any contact voxels of the same color.

[0454] For each centerline, we trace the curve through the voxel set to obtain the geometric representation of the corresponding fiber in the form of a sequence of connecting segments (polylines). This step is also part of FiberFind-AI in GeoDict.

[0455] This resulted in a digital 3D model of the fabric. Figures 44 to 46 Examples of fabrics with layered structures can be seen in the images.

[0456] Step 7: Calculation and Analysis of Samples

[0457] To obtain the "inter-filament bonding density," "filament density," "cavity length and height," and "percentage of cavities in the thickness of the nonwoven fabric," each cross-sectional filament segment was projected onto a plane, divided into sub-segments (each with a maximum thickness of 0.05 mm), and analyzed. The values ​​between segments were compared, and, where possible, adjacent segments with the same or similar results were grouped into layers. Layers A, B, and a possible C were designated, and the values ​​for each layer were averaged using the segment data.

[0458] [1]Buades,Antoni,Bartomeu Coll,and J-M.Morel."A non-local algorithmfor image denoising."Computer Vision and Pattern Recognition,2005.CVPR2005.IEEE Computer Society Conference on.Vol.2.IEEE,2005。

[0459] [2]Otsu,Nobuyuki."A threshold selection method from gray-levelhistograms."IEEE transactions on systems,man,and cybernetics 9.1(1979):62-66。

[0460] [3]Noh,Hyeonwoo,Seunghoon Hong,and Bohyung Han."Learningdeconvolution network for semantic segmentation."Proceedings of the IEEEinternational conference on computer vision.2015。

[0461] [4]Martín Abadi,Ashish Agarwal,Paul Barham,Eugene Brevdo,ZhifengChen,Craig Citro,Greg S.Corrado,Andy Davis,Jeffrey Dean,Matthieu Devin,Sanjay Ghemawat,Ian Goodfellow,Andrew Harp,Geoffrey Irving,Michael Isard,Rafal Jozefowicz,Yangqing Jia,Lukasz Kaiser,Manjunath Kudlur, Josh Levenberg, Dan Mané, Mike Schuster, Rajat Monga, Sherry Moore, Derek Murray, Chris Olah, Jonathon Shlens, Benoit Steiner, Ilya Sutskever, Kunal Talwar, Paul Tucker, Vincent Vanhoucke, Vijay Vasudevan, Fernanda Viégas, Oriol Vinyals, Pete Warden, Martin Wattenberg, Martin Wicke, Yuan Yu, and Xiaoqiang Zheng. "TensorFlow: Large-scalemachine learning on heterogeneous systems", 2015. Software available from tensorflow.org.

[0462] Industrial application

[0463] This invention can be applied anywhere a bulky nonwoven fabric requires a balance of softness and durability, such as as components of absorbent hygiene products (e.g., baby diapers, incontinence products, feminine hygiene products, changing pads, etc.) in the hygiene industry, or as part of wound sponges and / or protective clothing, surgical covers, pads, and other barrier materials in the healthcare field. Other applications include industrial uses, such as as part of protective clothing for filtration, insulation, packaging, sound absorption, footwear, automotive, furniture, etc. This invention is particularly advantageous for applications requiring increased bulkiness, compressibility, and resilience in fabrics, combined with the need for endless fibers.

Claims

1. A nonwoven fabric comprising multiple filament layers, wherein the fabric comprises - A first layer (A), which forms a first outer surface of the nonwoven fabric and includes a continuous multicomponent filament comprising a first component, the first component - Extending longitudinally along the filament, - Forming at least 20% of the surface area of ​​the filament - Filament-to-filament bonding is formed within the first layer (A), and - Having a melting point at least 5°C lower than the melting point of the other components of the filament in the first layer (A), and - Second layer (B), the second layer (B) comprising a continuous multi-component filament containing a first component, the first component - Extending longitudinally along the filament, - Forming at least 20% of the surface area of ​​the filament - Filament-to-filament bonding is formed within the second layer (B), and - Having a melting point at least 5°C lower than the melting point of the other components of the filament in the second layer (B), and - The loose density of the fabric is less than 60 kg / m³. 3 , Furthermore, the ratio of the interfilament bonding density of the first layer (A) to the interfilament bonding density of the second layer (B) is at least 2.

2. The nonwoven fabric of claim 1, wherein the fabric comprises a third layer (C) forming a second outer surface of the nonwoven fabric, such that a second layer (B) is positioned between a first layer (A) forming the first outer surface of the nonwoven fabric and a third layer (C) forming the second outer surface of the nonwoven fabric, and the third layer (C) comprises a continuous multicomponent filament comprising a first component, the first component... - Extending longitudinally along the filament, - Forming at least 20% of the surface of the filament, - Filament-to-filament bonding is formed within the third layer (C), and - It has a melting point that is at least 5°C lower than the melting point of the other components of the filament in the third layer (C).

3. The nonwoven fabric according to claim 1, wherein the ratio of the filament density of the first layer (A) to the filament density of the second layer (B) is at least 1.

5.

4. The nonwoven fabric according to claim 2, wherein the ratio of the filament density of the third layer (C) to the filament density of the second layer (B) is at least 1.

5.

5. The nonwoven fabric according to claim 1, wherein the ratio of the interfilament bonding density of the first layer (A) to the interfilament bonding density of the second layer (B) is at least 3.

0.

6. The nonwoven fabric according to claim 2, wherein the ratio of the interfilament bonding density of the third layer (C) to the interfilament bonding density of the second layer (B) is at least 2.

7. The nonwoven fabric of claim 1, wherein the second layer (B) comprises a cavity, wherein the cavity has a length extending along a plane defined by a machine direction and a transverse direction and a height extending perpendicular to the plane, wherein at least some of the cavities have a length-to-height ratio of at least 3:

1.

8. The nonwoven fabric of claim 7, wherein the height of the cavity forms at least 15% of the thickness of the nonwoven fabric.

9. The nonwoven fabric of claim 1, wherein the second layer (B) comprises a cavity, wherein the cavity has a length extending along a plane defined by a machine direction and a transverse direction, and the nonwoven fabric has a thickness extending perpendicular to the plane, wherein for at least some of the cavities, the ratio of the length of the cavity to the thickness of the nonwoven fabric is at least 3:

1.

10. The nonwoven fabric according to any one of the preceding claims, wherein the fabric comprises filaments having a crimpable cross-section.

11. The nonwoven fabric according to any one of claims 1 to 9, wherein the fabric comprises filaments having a non-curling cross-section, the filaments comprising a shrinkable polymer.

12. The nonwoven fabric according to any one of claims 1 to 9, wherein the first component of the first layer (A) and / or the first component of the second layer (B) comprises a bonding polymer selected from polyolefins, aliphatic polyesters, aromatic polyesters or copolymers thereof.

13. The nonwoven fabric according to any one of claims 1 to 9, wherein the first component of the first layer (A) and / or the first component of the second layer (B) comprises a bonding polymer selected from polypropylene, polyethylene, polylactic acid (PLA), polyethylene terephthalate (PET) or copolymers thereof (coPLA, coPET, coPP, coPE).

14. The nonwoven fabric of claim 12, wherein the other components of the first layer (A) and / or the other components of the second layer (B) comprise polymers selected from polyolefins, aliphatic polyesters, aromatic polyesters, or copolymers thereof.

15. The nonwoven fabric according to claim 13, wherein the other components of the first layer (A) and / or the other components of the second layer (B) comprise polymers selected from polypropylene, polyethylene, polylactic acid (PLA), polyethylene terephthalate (PET), or copolymers thereof (coPLA, coPET).

16. The nonwoven fabric according to any one of claims 1 to 9, wherein at least 65% by weight of the filaments of the first layer (A) and / or the filaments of the second layer (B) are composed of one or more polyolefin polymers.

17. The nonwoven fabric according to any one of claims 1 to 9, wherein at least one of the filament components comprises at least 65% by weight of a polyester polymer.

18. The nonwoven fabric according to any one of claims 1 to 9, wherein a. The continuous multicomponent filaments of the first layer and / or the second layer are bicomponent, and b. The first component comprises a polyolefin, and c. The other components include polyolefins.

19. The nonwoven fabric according to any one of claims 1 to 9, wherein a. The continuous multicomponent filaments of the first layer and / or the second layer are bicomponent, and b. The first component comprises a polyolefin, and c. Other components include polyester.

20. The nonwoven fabric according to any one of claims 1 to 9, wherein a. The continuous multicomponent filaments of the first layer and / or the second layer are bicomponent, and b. The first component comprises polyester, and c. The other components include polyester.

21. The nonwoven fabric according to any one of claims 1 to 9, wherein the fabric delamination strength is equal to or greater than 0.5 N.

22. The nonwoven fabric according to any one of claims 1 to 9, wherein the fabric delamination strength is equal to or less than 10.0 N.

23. The nonwoven fabric according to any one of claims 1 to 9, wherein the fabric comprises at least a first layer (i) and a second layer (ii) of filaments.

24. The nonwoven fabric of claim 23, wherein at least one layer of the nonwoven fabric comprises at least two layers.

25. The nonwoven fabric of claim 23, wherein the first layer (i) comprises at least the first layer (A).

26. The nonwoven fabric of claim 23, wherein the filaments in all layers of a layer comprise the same components arranged in the same manner on the cross-section of the filaments.

27. The nonwoven fabric of claim 23, wherein the filaments in the first layer are different from the filaments in the second layer in at least one of the following: at least one of the components, the arrangement of the components in cross-section, and the median fiber diameter.

28. The nonwoven fabric of claim 23, wherein the first layer (i) comprises bicomponent filaments having a concentric core / sheath structure or an eccentric core / sheath structure.

29. The nonwoven fabric of claim 23, wherein the second layer (ii) comprises bicomponent filaments having a side / side structure or an eccentric core / sheath structure.

30. The nonwoven fabric of claim 29, wherein the core of the bicomponent filament of the first layer (i) comprises polypropylene or a polypropylene blend, and / or the core component or one side component of the bicomponent filament of the second layer (ii) comprises polypropylene or a polypropylene blend.

31. The nonwoven fabric of claim 30, wherein the sheath of the bicomponent filament of the first layer (i) comprises polyethylene or a polyethylene blend, and the sheath component or one side component of the bicomponent filament of the second layer (ii) comprises polyethylene or a polyethylene blend.

32. The nonwoven fabric according to claim 31, wherein the melt flow rate of the polyethylene or polyethylene blend in the sheath of the bicomponent filament of the first layer (i) is higher than the melt flow rate of the polyethylene or polyethylene blend of the bicomponent filament of the second layer (ii).

33. The nonwoven fabric according to claim 31, wherein the sheath of the bicomponent filament of the first layer (i) forms 30% to 45% by weight of the filament, and the polyethylene or polyethylene blend of the bicomponent filament of the second layer (ii) forms 30% to 55% by weight of the filament.

34. The nonwoven fabric according to claim 23, wherein... - The filaments of the first layer (i) have a median fiber diameter of 10 micrometers to 17 micrometers, and / or - The filaments of the second layer (ii) have a median fiber diameter of 15 micrometers to 22 micrometers, and / or The filaments of the first layer (i) have a lower median fiber diameter than the filaments of the second layer (ii).

35. An absorbent hygiene product comprising a nonwoven fabric according to any one of claims 1 to 34.

36. A method for manufacturing a nonwoven fabric, comprising the following steps: a) Melting a. At least a first polymer material forming the first component, and b. A second polymer material that forms at least one other component and has a lower melting point than the first polymer material, and b) The molten polymer material is fed into the nozzle of the spinning box and extruded through the nozzle. a. The molten polymer material exiting the nozzle is used to form an endless filament. b. wherein the first polymer material extends in the longitudinal direction of the filament and forms at least a portion of the surface of the filament, and c) Cooling the formed filament with a fluid medium at a temperature of 10 °C to 90 °C and stretching the filament with a sag ratio of 200 to 1300 to achieve at least a semi-stable crystalline state of the second polymer material, and d) The filaments are randomly laid on a forming belt to form a nonwoven filament mat, and e) Pre-consolidating the nonwoven filament mat with heat flux for 1 ms to 10000 ms, and f) Preheating the filament mat with a heat flow having a temperature 5°C to 20°C lower than the melting temperature of the first polymer material, and g) The filament mat is consolidated by a heat flow having a temperature no more than 5°C lower than the melting temperature of the first polymer material and no more than 3°C higher than the melting temperature of the first polymer material, and the thus consolidated filament mat is cooled by an air flow having a temperature of 10°C to 40°C.

37. The method of manufacturing a nonwoven fabric according to claim 36, wherein intermediate cooling is performed between the pre-consolidation step e) and the preheating step f).

38. The method of manufacturing a nonwoven fabric according to claim 37, wherein the intermediate cooling is performed by exposing the pre-consolidated wadding to air.

39. The method of manufacturing a nonwoven fabric according to claim 37 or 38, wherein the intermediate cooling is performed by air having a temperature equal to or lower than 70°C.

40. The method of manufacturing a nonwoven fabric according to claim 38, wherein the intermediate cooling is performed by exposing the pre-consolidated wadding to ambient air.

41. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the consolidation of the wadding in step g), the heat flow is applied from alternating directions such that it enters the wadding from one side of the wadding and then from the other side of the wadding.

42. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein the heat flow in step e) and / or step f and / or step g) is provided by hot air.

43. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein no additional tension is applied to the wadding during the preheating period in step f).

44. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the preheating period in step f), the filament mat reaches a temperature of 10°C to 40°C.

45. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein at least a portion of step f) and / or step g) is performed by guiding the wadding along a roller of an air-through consolidation device.

46. ​​The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein at least a portion of step f) and / or step g) is carried out by guiding the wadding through a flat-plate furnace consolidation apparatus.

47. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the pre-consolidation step e), the pre-consolidation air velocity is set to 0.1 m / s to 10 m / s.

48. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the pre-consolidation step e), the pre-consolidation air temperature is 80°C to 200°C.

49. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the pre-consolidation step e), the pre-consolidation air temperature is 90°C to 150°C.

50. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein during the pre-consolidation in step e), the filament pad is exposed to the heat flow for a period of 2 ms to 1000 ms using air.

51. The method of manufacturing a nonwoven fabric according to any one of claims 36 to 38, wherein steps g), h), and i) are carried out in different sections.

Images