Nonwoven fabric and method for producing nonwoven fabric

Abstract

The invention relates to a nonwoven fabric made of continuous filaments, wherein the filaments are multi-component filaments and comprise at least a first polypropylene component comprising a base polypropylene and at least a second polypropylene component comprising a base polypropylene. The melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component is less than 5 °C. The base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component were polymerized with a catalyst from the same class of catalysts.

Description

[0001] The invention relates to a nonwoven fabric made of continuous filaments, wherein the filaments are multi-component filaments, in particular bi-component filaments, and comprise at least a first polypropylene component comprising a base polypropylene and at least a second polypropylene component comprising a base polypropylene. The invention also relates to a method for producing such a nonwoven fabric. According to the invention, the filaments are continuous filaments. Continuous filaments differ from short fibers, which have significantly shorter lengths of, for example, 1 mm to 60 mm, due to their virtually endless length. It is within the scope of the invention that the nonwoven fabric consists of, or essentially consists of, continuous filaments. Here and subsequently, the term "filaments" is used instead of "continuous filaments."

[0002] Nonwovens of the type described above and methods for producing such nonwovens are generally known in various embodiments from practical experience. For some applications, high strength, particularly high tensile strength, of the nonwovens is required or desired. This applies especially to the tensile strength in the machine direction (MD) and / or transverse to the machine direction (CD). Within the scope of the invention, machine direction (MD) refers specifically to the conveying direction F of the nonwoven on a lay-up device. In contrast, CD or CD direction refers to the direction transverse to the machine direction. With nonwovens known from practical experience, it has been shown that the strength properties achieved often do not meet all requirements. This applies to both nonwovens made from mono-component filaments and nonwovens made from multi-component filaments.

[0003] The strength or tensile strength of nonwovens can be influenced, for example, by the strength of the individual filaments themselves (single-filament strength) and also by the bonding points present between the filaments of the finished, bonded, or end-bonded nonwoven. These factors, in turn, can be influenced, particularly by the choice of raw materials for the filaments. Monocomponent filaments and nonwovens made from monocomponent filaments can be produced with relatively little effort, and it is nevertheless possible to influence the strength of the resulting filaments and nonwovens by selecting the appropriate raw material.Furthermore, it is known from practical experience that the properties of nonwovens can be more precisely controlled when using multi-component filaments, such as bi-component filaments, than the properties of nonwovens based on mono-component filaments. The individual components of the multi-component filaments can be optimized separately with regard to specific desired properties of the resulting nonwoven. In this way, for example, the bonding points between the filaments of the finished nonwoven and the strength of the individual filaments can be specifically influenced.

[0004] However, it has been shown that the high strengths, particularly tensile strengths, required for some applications of nonwovens cannot be achieved satisfactorily using methods known from practice. The strengths, or rather the tensile strengths, of many nonwovens known from practical use leave much to be desired. This is where the invention comes in.

[0005] In contrast, the invention addresses the technical problem of providing a nonwoven fabric of the type mentioned above, characterized by high strength, in particular high tensile strength, and which is nevertheless easy, reliable, and economical to produce. Furthermore, the invention addresses the technical problem of providing a method for producing such a nonwoven fabric.

[0006] To solve the technical problem, the invention teaches a nonwoven fabric made of continuous filaments, wherein the filaments are multi-component filaments, in particular bi-component filaments, and have at least a first polypropylene component comprising a base polypropylene and at least a second polypropylene component comprising a base polypropylene. wherein the melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component is less than 5 °C, preferably less than 4 °C, preferably less than 3 °C, particularly preferably less than 2 °C and most preferably less than 1 °C, and wherein the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component were polymerized with a catalyst from the same class of catalyst and preferably each with a metallocene catalyst or each with a Ziegler-Natta catalyst.

[0007] It is preferred that the nonwoven fabric is end-bonded, preferably thermally bonded, and preferably has an embossed pattern of bonded areas, in particular bond points. The nonwoven fabric is very preferably end-bonded or thermally bonded using a calender, wherein the calender preferably comprises a first calender roll with embossing elements on its outer surface (engraving roll) and / or a second calender roll with a smooth outer surface (S-roll).

[0008] According to the invention, the melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component is less than 5 °C. In this context, melting point also refers specifically to melting temperature. The melting point or melting temperature of the base polypropylenes is measured, in particular, by differential scanning calorimetry (DSC) according to ISO 11357-3:2011.

[0009] According to the invention, the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component were polymerized with a catalyst from the same catalyst class, preferably with a metallocene catalyst or a Ziegler-Natta catalyst. Within the scope of the invention, the term "same catalyst class" means in particular that a polymerization catalyst of the same type was used for the polymerization of the base polypropylenes, for example, a homogeneous catalyst, a heterogeneous catalyst, or a mixed catalyst. According to a preferred embodiment, the base polypropylenes of the first and second polypropylene components were polymerized with a Ziegler-Natta catalyst or a metallocene catalyst. In this case, "catalyst class" refers in particular to a metallocene catalyst or a Ziegler-Natta catalyst.Polypropylene polymerized with metallocene catalysts is characterized by a narrow molecular weight distribution and / or high stereoregularity, particularly compared to polypropylene polymerized with Ziegler-Natta catalysts. According to the invention, the molecular weight distribution of a polymer or polypropylene can be measured, particularly according to ASTM D1238-13. When measuring the molecular weight distributions of polypropylenes or base polypropylenes according to ASTM D1238-13, trichlorobenzene is advantageously used as the solvent for the polypropylene plastic, and the measurement on the solution is performed, in particular, at a temperature of 160 °C, with a concentration of 1.5 g / l, and an IR sensor is used.The columns used in the measurement are calibrated with polystyrene standards, and the measurement results are converted to "polypropylene" using the Mark Houwink equation. The following parameter set is conveniently used: Polystyrene: α = 0.7; K = 0.0138 mL / g; Polypropylene: α = 0.707; K = 0.0242 mL / g.

[0010] It is within the scope of the invention that the second polypropylene component is arranged on the outer surface of the multi-component filaments. It is particularly preferred that the filaments are multi-component or bi-component filaments with a core-sheath configuration, especially with a centric or symmetrical core-sheath configuration, wherein preferably the first polypropylene component forms the core and the second polypropylene component forms the sheath of the filaments. Within the scope of the invention, the term "filament configuration" refers in particular to the cross-sectional configuration of the filaments. In principle, other cross-sectional configurations of the filaments of the nonwoven fabric are also within the scope of the invention, for example, a side-by-side configuration, an eccentric core-sheath configuration, a trilobal configuration, or the like.

[0011] The invention, in connection with the embodiment in which multi-component filaments or bi-component filaments with core-sheath configuration, in particular with a centric or symmetrical core-sheath configuration, are used, is based on the finding that the properties of the filament core and the properties of the filament sheath can be specifically influenced by the design of the first and the second polypropylene component, wherein, due to the very small melting point difference provided according to the invention between the base polypropylenes used and due to the polymerization of the base polypropylenes with a catalyst from the same catalyst class, filaments are realized with which a nonwoven fabric can be provided that is characterized by a surprisingly high strength, in particular by a surprisingly high tensile strength.The basic polypropylenes are very similar, at least with regard to some of their properties—especially their melting point or melting temperature and their polymerization catalyst—so that multi-component or bi-component filaments result that—at least with regard to certain properties—replicate a mono-component filament. Surprisingly, however, the strength values ​​of the resulting nonwoven fabric are significantly higher than those of comparable mono-component filaments. This will be explained in more detail below. A similar finding underlies the design of multi-component or bi-component filaments with different cross-sectional configurations, for example, a side-by-side configuration.

[0012] According to the invention, the first polypropylene component comprises a base polypropylene (first base polypropylene) and the second polypropylene component comprises a base polypropylene (second base polypropylene). Within the scope of the invention, the term "base polypropylene" means, in particular, that the first polypropylene component and the second polypropylene component contain the respective base polypropylene in a proportion of at least 55 wt.%, preferably at least 60 wt.%, and more preferably at least 65 wt.%. It is particularly preferred that the first polypropylene component and / or the second polypropylene component contain the respective base polypropylene in a proportion of at least 70 wt.%, preferably at least 80 wt.%, more preferably at least 85 wt.%, more preferably at least 90 wt.%, and most preferably at least 92 wt.%.It is further preferred that the first polypropylene component and / or the second polypropylene component contains / contain the respective base polypropylene to a proportion of at least 94 wt.%.

[0013] One embodiment of the nonwoven fabric according to the invention, which is of particular importance within the scope of the invention, is characterized in that the first polypropylene component and / or the second polypropylene component consists of, or essentially consists of, the respective base polypropylene. When, within the scope of the invention, it is stated that a component consists of, or essentially consists of, a plastic – for example, that the first polypropylene component consists essentially of the (first) base polypropylene and / or that the second polypropylene component consists essentially of the (second) base polypropylene – "essentially consists" means, in particular, that the component consists of at least 95% by weight, preferably at least 98% by weight, and especially preferably at least 99% by weight, of the plastic.This takes particular account of the fact that, in addition to the aforementioned plastic, additives such as plasticizers, fillers, colors, lubricants, additives and the like may also be present in small quantities.

[0014] It is within the scope of the invention that the first polypropylene component and / or the second polypropylene component is / are a mixture or blend of the respective base polypropylene and at least one additive. According to a preferred embodiment, the additive may be a substance that increases the melt flow rate (MFR) of the first polypropylene component and / or the second polypropylene component. A particularly preferred embodiment of the invention is characterized in that the second polypropylene component forms the sheath of the multi-component filaments or bi-component filaments with a core-sheath configuration, and that this second polypropylene component is a mixture or blend of the base polypropylene of the second polypropylene component and at least one additive.In principle, the additive can also be a substance that allows for the adjustment of other properties of the respective polypropylene component. For example, additives containing peroxides can be used to reduce the molecular weight of the base polypropylenes.

[0015] Within the scope of the invention, it is particularly preferred that different polypropylenes are used as the base polypropylene of the first polypropylene component and as the base polypropylene of the second polypropylene component. The term "different polypropylenes" specifically means that the two base polypropylenes differ with respect to at least one property, for example, their melting point, molecular weight distribution, tacticity, melt flow rate (MFR), and the like. This embodiment, in which different polypropylenes are used as the base polypropylene of the first polypropylene component and as the base polypropylene of the second polypropylene component, is of particular importance within the scope of the invention.For the base polypropylene of the first polypropylene component, the term "first base polypropylene" is used here and below, and for the base polypropylene of the second polypropylene component, the term "second base polypropylene" is used.

[0016] According to an alternative embodiment of the invention, the same polypropylene is used as the base polypropylene of the first polypropylene component and as the base polypropylene of the second polypropylene component, and then at least one polypropylene component, preferably at least the second polypropylene component, is a mixture or blend of the base polypropylene and at least one additive. More preferably, the second polypropylene component, which according to one embodiment is a mixture or blend of the base polypropylene and at least one additive, forms the sheath component of multi-component filaments or bi-component filaments with a core-sheath configuration provided according to a preferred embodiment.

[0017] It is within the scope of the invention that the proportion of the at least one additive in the first polypropylene component and / or in the second polypropylene component is 0.1 to 30.0 wt.%, preferably 0.2 to 20.0 wt.%, more preferably 0.5 to 15.0 wt.%, particularly preferably 1.0 to 10.0 wt.%, most preferably 1.5 to 9.0 wt.%, and further preferably 2.0 to 8.0 wt.%, for example 3.0 to 6.0 wt.%. More preferably, the at least one additive is an additive polypropylene. According to a highly preferred embodiment, this additive polypropylene is a polypropylene that has a higher melt flow rate (MFR) than the base polypropylene to which the additive or the additive polypropylene is added.

[0018] This advantageously increases the melt flow rate (MFR) of the resulting polypropylene component. According to one embodiment, at least the second polypropylene component comprises an additive in the form of an additional polypropylene, preferably in the proportions specified above, and more preferably, this second polypropylene component forms the sheath component of multi-component filaments or bi-component filaments with a core-sheath configuration provided according to the preferred embodiment.

[0019] According to the invention, the melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component is less than 5 °C, preferably less than 4 °C, more preferably less than 3 °C, particularly preferably less than 2 °C, and most preferably less than 1 °C. It is within the scope of the invention that the melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component is 0.5 °C to 5 °C, preferably 1 °C to 4 °C. An embodiment that is of particular importance within the scope of the invention is characterized in that the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component have the same or substantially the same melting point, and these are particularly preferably different polypropylenes or base polypropylenes.Within the scope of the invention, the fact that the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component have the same or substantially the same melting point means in particular that the melting point difference between the two base polypropylenes is 0 °C or approximately 0 °C.

[0020] A preferred embodiment of the invention is characterized in that the melt flow rate (MFR) of the second polypropylene component is greater than the melt flow rate (MFR) of the first polypropylene component, and wherein the ratio of the melt flow rate (MFR) of the second polypropylene component to the melt flow rate (MFR) of the first polypropylene component is particularly 1.02 to 10, preferably 1.05 to 8, more preferably 1.1 to 6, more preferably 1.2 to 3, and most preferably 1.3 to 2.2, for example 1.35 to 2.0. This embodiment is based on the finding that the resulting nonwoven fabric—particularly after end-bonding measures—is characterized by an advantageous bond between the individual filaments, so that the strength or tensile strength of the nonwoven fabric can be further improved.This applies particularly when, according to a preferred embodiment, the second polypropylene component is arranged on the outer surface of the filaments and preferably forms the sheath component of multi-component filaments or bi-component filaments with a core-sheath configuration. Within the scope of the invention, the melt flow rate is preferably measured according to ASTM D1238-13 at 230 °C and 2.16 kg (condition B) in grams of polymer per 10 minutes (g / 10 min). The melt flow rate (MFR) of mixtures or blends is determined by measuring the melt flow rate (MFR) of the polypropylene or base polypropylene and by using a logarithmic calculation to determine the melt flow rate of the blend or mixture.

[0021] Preferably, the first polypropylene component has a melt flow rate (MFR) of at least 10 g / 10 min, preferably at least 12 g / 10 min, and / or preferably, the second polypropylene component has a melt flow rate (MFR) of at least 15 g / 10 min, preferably at least 20 g / 10 min. It is also generally within the scope of the invention for the melt flow rate (MFR) of the first polypropylene component to be greater than the melt flow rate (MFR) of the second polypropylene component.

[0022] It is within the scope of the invention that the ratio of the mass of the first polypropylene component to the mass of the second polypropylene component is 95:5 to 50:50, preferably 90:10 to 55:45, more preferably 85:15 to 60:40, particularly preferably 85:15 to 65:35, and most preferably 85:15 to 70:30, for example 80:20 to 75:25. This embodiment is based on the understanding that this selection of the mass proportions of the polypropylene components achieves an optimal compromise between the influence on the strength or tensile strength of the nonwoven fabric by the resulting bonding points between the filaments of the nonwoven fabric—especially after end-bonding measures—and by the individual filament strength. This applies particularly when, according to a preferred embodiment, the second polypropylene component is arranged on the outer surface of the filaments and preferably forms the sheath component of multi-component filaments.forms bicomponent filaments with a core-sheath configuration.

[0023] A particularly preferred embodiment of the nonwoven fabric according to the invention is characterized in that the base polypropylene of the first polypropylene component and / or the base polypropylene of the second polypropylene component and / or the at least one additional polypropylene is / are a homo-polypropylene or a polypropylene copolymer.

[0024] It is within the scope of the invention that the nonwoven fabric comprises only one layer of nonwoven material made of continuous filaments. However, it is also within the scope of the invention that the nonwoven fabric comprises several layers of nonwoven material arranged one above the other, which are combined, in particular, to form a nonwoven laminate. According to a preferred embodiment, the nonwoven fabric thus comprises a single layer of nonwoven material made of continuous filaments. In this case, the basis weight of the nonwoven fabric is preferably 20 g / m² to 110 g / m², more preferably 25 g / m² to 85 g / m², and very preferably 30 g / m² to 75 g / m². According to an alternative preferred embodiment, the nonwoven fabric comprises at least two, more preferably at least three, and in particular three, layers of nonwoven material made of continuous filaments. Then the basis weight of the nonwoven fabric is preferably between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², very preferably from 5 g / m² to 18 g / m².Advantageously, these at least two nonwoven layers are combined to form a nonwoven laminate. It is within the scope of the invention that, in the embodiment with at least two, preferably at least three, and in particular three, nonwoven layers, the properties of the nonwoven layers or the filaments of the nonwoven layers are identical or substantially identical. However, it is also possible in principle for the nonwoven layers or the filaments of the nonwoven layers to differ from one another in their properties. A preferred embodiment, however, is one in which at least two, and in particular at least three, preferably three, identical or substantially identical nonwoven layers are laid on top of one another and, further preferably, combined to form a nonwoven laminate.

[0025] It is within the scope of the invention that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably from 25 g / m² to 85 g / m², and more preferably from 30 g / m² to 75 g / m². According to a further preferred embodiment, the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², and more preferably from 5 g / m² to 18 g / m².

[0026] It is particularly preferred that the nonwoven fabric is end-bonded, especially thermally bonded, and preferably has an embossed pattern of bonded areas, especially bond points. It is very preferably a nonwoven fabric that has been thermally bonded or thermobonded using a calender. The preferred properties of the nonwoven fabric listed below preferably relate to such an end-bonded or thermally bonded nonwoven fabric.

[0027] A preferred embodiment of the invention is characterized in that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably of 25 g / m² to 85 g / m², preferably of 30 g / m² to 75 g / m², and wherein the specific tensile strength of the nonwoven fabric in the MD direction is preferably 2.5 to 7.2 N / 5 cm per g / m², preferably 3.0 to 7.0 N / 5 cm per g / m², preferably 3.2 to 6.8 N / 5 cm per g / m², particularly preferably 3.4 to 6.7 N / 5 cm per g / m², and most preferably 3.5 to 6.5 N / 5 cm per g / m², and / or wherein the specific tensile strength of the nonwoven fabric in the CD direction is preferably 2.0 to 4.0 N / 5 cm per g / m 2< , preferably 2.1 to 3.8 N / 5 cm per g / m 2< , preferably 2.2 to 3.7 N / 5 cm per g / m 2< , particularly preferably 2.3 to 3.6 N / 5 cm per g / m 2< .It is within the scope of the invention that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably 25 g / m² to 85 g / m², and preferably 30 g / m² to 75 g / m², and wherein the tensile strength of the nonwoven fabric in the MD direction is advantageously 100 N / 5 cm to 500 N / 5 cm, preferably 120 N / 5 cm to 480 N / 5 cm, and / or wherein the tensile strength of the nonwoven fabric in the CD direction is 70 N / 5 cm to 350 N / 5 cm, preferably 90 N / 5 cm to 320 N / 5 cm. The nonwoven fabric with the aforementioned basis weights and the aforementioned tensile strength values ​​or specific tensile strength values ​​is preferably a single-layer nonwoven fabric with a single layer of nonwoven material.The properties of the nonwoven fabric described above with regard to tensile strength apply in particular to a nonwoven fabric that is end-strengthened, preferably thermally end-strengthened, and preferably has an embossed pattern of bonding points, in particular bonding points.

[0028] A further or alternative preferred embodiment of the invention is characterized in that the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², more preferably from 5 g / m² to 18 g / m², and wherein the specific tensile strength of the nonwoven fabric in the MD direction is preferably 1.5 to 4.5 N / 5 cm per g / m², more preferably 1.7 to 4.0 N / 5 cm per g / m², more preferably 1.8 to 3.8 N / 5 cm per g / m², more preferably 2.0 to 3.5 N / 5 cm per g / m², and most preferably 2.0 to 3.0 N / 5 cm per g / m², and / or wherein the specific tensile strength of the nonwoven fabric in the CD direction is preferably 1.0 to 2.5 N / 5 cm per g / m 2< , preferably 1.1 to 2.0 N / 5 cm per g / m 2< , preferably 1.2 to 1.9 N / 5 cm per g / m 2< , particularly preferably 1.2 to 1.8 N / 5 cm per g / m 2< .It is further preferred that the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably between 2 g / m² and 19 g / m², and preferably between 5 g / m² and 18 g / m², and wherein the tensile strength of the nonwoven fabric in the MD direction is expediently 20 N / 5 cm to 40 N / 5 cm, preferably 22 N / 5 cm to 38 N / 5 cm, and / or wherein the tensile strength of the nonwoven fabric in the CD direction is 8 N / 5 cm to 22 N / 5 cm, preferably 10 N / 5 cm to 21 N / 5 cm. The nonwoven fabric with the basis weights and tensile strength values ​​or specific tensile strength values ​​specified above is in particular a nonwoven fabric with at least two, preferably at least three, and in particular three, layers of nonwoven fabric, which are further preferably combined to form a laminate.The properties of the nonwoven fabric described above with regard to tensile strength apply in particular to a nonwoven fabric that is end-strengthened, preferably thermally end-strengthened, and preferably has an embossed pattern of bonding points, in particular bonding points.

[0029] The tensile strength of the nonwoven fabric according to the invention is determined in particular according to the following method: "Determination of Tensile Strength (based on EDANA 20.2-89)": In N / 5 cm; with 50 mm sample width; 100 mm clamping length; 200 mm / min test speed.

[0030] As mentioned above, the nonwoven fabric is preferably end-bonded, in particular thermally end-bonded, and preferably has an embossed pattern of bonding points, especially bond points. During the end-bonding process, the nonwoven fabric is expediently consolidated, preferably by a calender, and for this purpose is preferably detached from the lay-up device that guides the nonwoven fabric. Pre-bonding measures, on the other hand, serve in particular to pre-bond or compact the nonwoven fabric for non-destructive onward transport on the lay-up device. An embossed pattern is preferably introduced into the nonwoven fabric during an end-bonding process. Expediently, the embossed pattern is introduced into the nonwoven fabric during an end-bonding process by at least one calender roll with a complementary embossing pattern of embossing elements.

[0031] It is within the scope of the invention that the nonwoven fabric has an embossed pattern of bonding sites, in particular bonding points, and wherein the proportion of the pore volume in the region of a bonding site is 1.0% to 12.0%, preferably 1.5% to 10.0%, more preferably 2.0% to 7.0%, and particularly preferably 2.5% to 6.5%. Within the scope of the invention, "proportion of pore volume" refers in particular to the proportion of the pore volume to the total volume of the bonding site. Within the scope of the invention, the proportion of the pore volume in the region of a bonding site is preferably determined by micro-computed tomography (µCT). Additionally or alternatively, the proportion of the pore volume in the region of a bonding site can be determined by porometry using a porosimeter or autoporosimeter.The embodiment of the nonwoven fabric according to the invention, featuring an embossed pattern of bonding points, wherein the proportion of the pore volume in the region of a bonding point lies within the range specified above, is based on the understanding that such low porosity in the region of the bonding points further increases the strength or tensile strength of the nonwoven fabric. Preferably, the nonwoven fabric, which has a pore volume in the region of a bonding point within the ranges specified above, has a basis weight of 20 g / m² to 110 g / m², more preferably of 25 g / m² to 85 g / m², and more preferably of 30 g / m² to 75 g / m².

[0032] A particularly preferred embodiment of the nonwoven fabric according to the invention is characterized in that the tensile strength and / or the specific tensile strength of the nonwoven fabric in the MD direction and / or in the CD direction is greater than 4%, in particular more than 6%, preferably more than 10%, preferably more than 15%, and particularly preferably more than 20%, than the corresponding tensile strength and / or the corresponding specific tensile strength of a comparable nonwoven fabric made from monocomponent filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions.It is further preferred that the tensile strength and / or the specific tensile strength of the nonwoven fabric in the MD direction and / or in the CD direction is greater than 25%, in particular more than 30%, preferably more than 40%, more preferably more than 50%, further preferably more than 60%, particularly preferably more than 70%, and most preferably more than 80%, for example, more than 90%, than the corresponding tensile strength and / or the corresponding specific tensile strength of a comparable nonwoven fabric produced from monocomponent filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions. The properties described above apply in particular to a nonwoven fabric that is end-bonded, preferably thermally end-bonded, and preferably has an embossed pattern of bonding sites, in particular bonding points.

[0033] Within the scope of the invention, the fact that the comparison nonwoven fabric is produced under the same conditions means, in particular, that the comparison nonwoven fabric is produced using the same apparatus as the nonwoven fabric according to the invention and under the same conditions. The comparison nonwoven fabric has the same number of nonwoven layers as the nonwoven fabric according to the invention, and all nonwoven layers of the comparison nonwoven fabric are produced under the same conditions as the nonwoven layers of the nonwoven fabric according to the invention. In particular, pre-bonding, bonding, and final bonding processes, as well as the introduction of an embossed pattern from bonding points, are carried out in the comparison nonwoven fabric in the same manner as in the nonwoven fabric according to the invention. The measurement of the tensile strength or specific tensile strength of the comparison nonwoven fabric and the nonwoven fabric according to the invention is carried out as already described above.The invention recognizes that the nonwoven fabric according to the invention, made from multi-component filaments, in particular from bi-component filaments, offers considerable advantages with regard to tensile strength or specific tensile strength in the MD direction and / or in the CD direction compared to a nonwoven fabric made from mono-component filaments of the first polypropylene component or the second polypropylene component, which is otherwise produced under the same conditions. Due to the similarity of the polypropylene components or the base polypropylenes according to the invention, at least with respect to some properties, bi-component filaments are produced that effectively mimic a mono-component filament – ​​at least with respect to certain properties – whereby, surprisingly, the strength values ​​or specific strength values ​​of the resulting nonwoven fabric are significantly higher than those of a comparable nonwoven fabric made from mono-component filaments.

[0034] It is within the scope of the invention that the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is at least 200 J / m², preferably at least 300 J / m², more preferably at least 400 J / m², and particularly preferably at least 500 J / m². The TEA values ​​and total TEA values ​​specified here and below apply in particular to a bonded, preferably thermally bonded, nonwoven fabric, which preferably has an embossed pattern of bonding sites, in particular bonding points.

[0035] It is highly preferred that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably of 25 g / m² to 85 g / m², preferably of 30 g / m² to 75 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is at least 1500 J / m², in particular at least 2500 J / m², preferably at least 4000 J / m², preferably at least 5000 J / m², particularly preferably at least 6000 J / m², most preferably at least 8000 J / m², for example at least 10000 J / m².

[0036] Another or alternative preferred embodiment of the nonwoven fabric according to the invention is characterized in that the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², preferably from 5 g / m² to 18 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is at least 200 J / m², in particular at least 300 J / m², preferably at least 400 J / m², preferably at least 500 J / m².

[0037] Within the scope of the invention, the TEA value refers in particular to the energy absorption of the nonwoven fabric under tensile stress (Tensile Energy Absorption, TEA). The TEA value in the MD direction and in the CD direction is determined, within the scope of the invention, specifically from the area under the force-strain curve at maximum force (y-value) and maximum force-strain (x-value), respectively. The recording of the force-strain curve in the MD direction and in the CD direction is preferably carried out on dry, untreated nonwoven fabric samples (test specimens) analogous to the test standard DIN EN ISO 9073-3:2023-09. It is within the scope of the invention that, for this purpose, preferably at least five sufficiently long nonwoven fabric samples, each with a width of 50 mm, are taken equidistantly across the roll width or material section width in the MD and CD directions. These samples are clamped between two clamping devices with a distance of 100 mm, so that the length of the samples examined / measured is 100 mm.These nonwoven samples are then tensioned using a tensioning machine at a feed rate of 100 mm / min up to a preload of 0.5 N. In this state, the measurement is reset to zero, and the actual measurement begins. The tensioning machine operates at a feed rate of 200 mm / min. The TEA value is determined in both the MD and CD directions as the arithmetic mean of the measured samples. The total TEA value is calculated as the sum of the MD TEA value (in J / m²) and the CD TEA value (in J / m²).

[0038] It is within the scope of the invention that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably of 25 g / m² to 85 g / m², preferably of 30 g / m² to 75 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is 1500 to 15000 J / m², preferably 2500 to 13000 J / m², and / or wherein the MD-TEA value of the nonwoven fabric is 950 to 8500 J / m², preferably 1500 to 8000 J / m², and / or wherein the CD-TEA value of the nonwoven fabric is 500 to 6000 J / m², preferably 1500 to 5500 J / m² < .

[0039] According to a further preferred or alternative embodiment, the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², preferably from 5 g / m² to 18 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is 200 to 600 J / m², preferably 250 to 550 J / m², and / or wherein the MD-TEA value of the nonwoven fabric is 125 to 400 J / m², preferably 140 to 350 J / m², and / or wherein the CD-TEA value of the nonwoven fabric is 80 to 250 J / m², preferably 90 to 240 J / m².

[0040] A particularly preferred embodiment of the invention is characterized in that the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is greater than 5%, preferably more than 10%, preferably more than 15%, particularly preferably more than 20%, and most preferably more than 25% than the corresponding total TEA value (MD-TEA + CD-TEA) of a reference nonwoven fabric produced from monocomponent filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions. In this embodiment, the reference nonwoven fabric is subject to the same specifications as described above, particularly with regard to the apparatus for producing the reference nonwoven fabric and the conditions for producing the reference nonwoven fabric.It is further preferred that the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is greater than 30%, preferably more than 40%, preferably more than 50%, particularly preferably more than 60%, most preferably more than 70%, for example more than 80%, than the corresponding total TEA value (MD-TEA + CD-TEA) of a comparison nonwoven fabric made from mono-component filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions.

[0041] It is preferred that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably of 25 g / m² to 85 g / m², preferably of 30 g / m² to 75 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is greater than 40%, preferably more than 80%, particularly preferably more than 100%, further preferably more than 200%, and most preferably more than 300% than the corresponding total TEA value (MD-TEA + CD-TEA) of a comparable nonwoven fabric made from mono-component filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions.

[0042] According to a further or alternative preferred embodiment of the nonwoven fabric according to the invention, the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², preferably from 5 g / m² to 18 g / m², and wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric is greater than 15%, preferably more than 25%, preferably more than 30%, and particularly preferably more than 50% than the corresponding total TEA value (MD-TEA + CD-TEA) of a comparison nonwoven fabric made from mono-component filaments of the first polypropylene component or the second polypropylene component and otherwise under the same conditions.

[0043] It is within the scope of the invention that the filaments have a titer of less than 2.3 den, preferably less than 2.1 den, preferably less than 1.9 den, and particularly preferably a titer of 1.0 to 2.2 den, most preferably of 1.2 to 2.0 den, for example of 1.4 to 1.8 den.

[0044] To solve the technical problem, the invention further teaches a method for producing a nonwoven fabric described above, wherein filaments are produced with at least one spinning device, in particular with at least one spinnerette, and are laid down to form the nonwoven fabric on at least one depositing device, in particular on at least one depositing screen belt.

[0045] It is within the scope of the invention that the nonwoven fabric or the nonwoven layers of the nonwoven fabric according to the invention are produced by a spunbond process. A preferred spunbond process for the nonwoven fabric or the nonwoven layers according to the invention is described below. The filaments or continuous filaments of the nonwoven fabric or the nonwoven layers are spun using a spinning device designed as a spinnerette and subsequently cooled in a cooling device with a cooling chamber. It is within the scope of the invention that a monomer extraction device is arranged between the spinnerette and the cooling device, with which interfering gases occurring during the spinning process can be removed from the device. After passing through the cooling device, the filaments are expediently guided through a drawing device to draw the continuous filaments.The stretching device preferably has an intermediate channel that connects the cooling device to a stretching chute of the stretching device. According to a particularly preferred embodiment of the invention, the assembly consisting of the cooling device and the stretching device, or the assembly consisting of the cooling device, the intermediate channel, and the stretching chute, is designed as a closed unit, and apart from the supply of cooling air to the cooling device, no further air is supplied to this unit from the outside.

[0046] Preferably, at least one diffuser is connected to the drawing device in the direction of filament flow, through which the continuous filaments are guided. Advantageously, after passing through the at least one diffuser, the continuous filaments are deposited onto a depositing device, which is preferably designed as a depositing screen belt. The depositing screen belt is preferably a continuously circulating belt. Advantageously, the depositing screen belt is designed to be air-permeable so that process air can be extracted from below through the depositing screen belt. Preferably, at least one extraction device is provided for extracting the process air from under the depositing screen belt.If the nonwoven fabric according to an embodiment of the invention has at least two, preferably at least three, layers of nonwoven fabric, then the device for producing the corresponding nonwoven fabric within the framework of the method according to the invention preferably has at least two, preferably at least three, spinnerets or spinner beams with the components described above arranged in the area or below the spinneret, and the devices for producing the nonwoven layers are preferably arranged above a single depositing device, in particular above a single depositing screen belt, on which the nonwoven layers of the nonwoven fabric are placed one on top of the other and are then preferably combined to form the nonwoven laminate.

[0047] It is within the scope of the inventive method that the nonwoven fabric is end-strengthened with at least one consolidation device, in particular with at least one calender roll, and wherein the temperature, in particular the surface temperature, of the at least one consolidation device, in particular the at least one calender roll, is preferably 120 °C to 180 °C, preferably 130 °C to 175 °C, preferably 140 °C to 170 °C, very preferably 145 °C to 165 °C. According to a particularly preferred embodiment of the method according to the invention, the nonwoven fabric is end-strengthened with a consolidation device designed as a calender with at least two calender rolls, and advantageously the surface temperature of at least one calender roll of the calender, preferably both calender rolls of the calender, is 120 °C to 180 °C, preferably 130 °C to 175 °C, preferably 140 °C to 170 °C, very preferably 145 °C to 165 °C.In a highly preferred embodiment, the solidification device, in particular the calender, comprises at least one calender roll (engraving roll) for imprinting a pattern of bonding points, in particular bonding points, wherein the calender roll preferably has a complementary embossing pattern of embossing elements on its outer surface. More preferably, the solidification device, in particular the calender, comprises at least one calender roll (S-roll) with a smooth outer surface.

[0048] It is within the scope of the invention that the complementary embossing pattern of the at least one calender roll for introducing an embossing pattern of bonding sites or bonding points into the nonwoven fabric has an embossing area of ​​5% to 35%, preferably 10% to 25%, and / or a figure density of 10 Fig / cm²< to 100 Fig / cm²<, preferably 25 Fig / cm²< to 75 Fig / cm²<.

[0049] It is within the scope of the invention that the temperature, in particular the surface temperature, of the at least one solidification unit, in particular the at least one calender roll, is at least 1 °C, preferably at least 2 °C, more preferably at least 3 °C, more preferably at least 4 °C, and most preferably at least 5 °C lower than the melting point of the base polypropylene of the second polypropylene component and / or the melting point of the base polypropylene of the first polypropylene component. Preferably, these specifications refer to the two calender rolls of a solidification unit designed as a calender.

[0050] It is within the scope of the inventive method that the speed of the laying device, in particular the speed of the laying screen belt, is 30 m / min to 1100 m / min, preferably 40 m / min to 1000 m / min. It is within the scope of the invention that the nonwoven fabric has a basis weight of 20 g / m² to 110 g / m², preferably 25 g / m² to 85 g / m², and preferably 30 g / m² to 75 g / m², and wherein the speed of the laying device, in particular the speed of the laying screen belt, is 30 m / min to 120 m / min, preferably 40 m / min to 110 m / min. It is further or alternatively within the scope of the invention that the nonwoven fabric has a basis weight between 1 g / m² and 20 g / m², preferably from 2 g / m² to 19 g / m², preferably from 5 g / m² to 18 g / m², and wherein the speed of the laying device, in particular the speed of the laying screen belt, is 250 to 1200 m / min, preferably 500 to 1100 m / min. Exemplary embodiment 1 according to the invention:

[0051] In a first embodiment according to the invention, a single-layer nonwoven fabric was produced from bicomponent filaments with a centric or symmetrical core-sheath configuration. The core component of the bicomponent filaments was formed by a first polypropylene component, which consisted of, or essentially consisted of, a first base polypropylene. A second polypropylene component, which consisted of, or essentially consisted of, a second base polypropylene, was used for the sheath component. The bicomponent filaments were produced as continuous filaments by the spunbond process in an apparatus or by the process described above for the production of nonwovens or spunbond nonwovens. The bicomponent filaments were produced with a filament fineness of 1.6 denier.The nonwoven fabric was end-hardened using a calender at a surface temperature of 155 °C for the engraving roller and 150 °C for the S-roll, resulting in an embossed area of ​​18.1% with oval hardening features and a density of 49.9 g / cm². A homopolypropylene with a melt flow rate of 15 g / 10 min was used as the first polypropylene component, or first base polypropylene. This first polypropylene component, or first base polypropylene, formed the core of the bicomponent filaments of the continuous filaments in the first embodiment of the invention. The homopolypropylene "Total MR 2002" was used here as the first polypropylene component, or first base polypropylene. This is a metallocene polypropylene polymerized with a metallocene catalyst. The second polypropylene component, orA homopolypropylene with a melt flow rate (MFR) of 25 g / 10 min was used as the second base polypropylene. This second polypropylene component, or base polypropylene, formed the sheath of the core-sheath bicomponent filaments. The homopolypropylene "Total MR 2001" was used for this second polypropylene component, or base polypropylene. This is a metallocene polypropylene polymerized with a metallocene catalyst.

[0052] The ratio of the mass of the first polypropylene component to the mass of the second polypropylene component was 80:20. The speed of the laying device, or the speed of the laying screen belt, was 62 m / min. The basis weight of the resulting nonwoven fabric was 66 g / m². The melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component was 0°C and approximately 0°C, respectively. Both polypropylenes have a melting point of 151°C. The specific tensile strength of the nonwoven fabric in the MD direction was 4.9 N / 5 cm per g / m², and the specific tensile strength of the nonwoven fabric in the CD direction was 3.3 N / 5 cm per g / m². The total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric was 6247 J / m². The MD-TEA value of the nonwoven fabric was 3824 J / m²< and the CD-TEA value of the nonwoven fabric was 2423 J / m²< . Comparison nonwoven fabric 1:

[0053] A comparison nonwoven fabric 1 was produced from monocomponent filaments of the first polypropylene component described above for the first embodiment of the invention, and otherwise under the same conditions as in the first embodiment of the invention. The resulting comparison nonwoven fabric 1 was identical to the nonwoven fabric of the first embodiment of the invention, as described above, with respect to its filament titer and its basis weight. The comparison nonwoven fabric 1 exhibited a specific tensile strength in the MD direction of 2.6 N / 5 cm per g / m² and in the CD direction of 1.8 N / 5 cm per g / m². The comparison nonwoven fabric had a total TEA value of 1639 J / m², wherein the MD-TEA value was 901 J / m² and the CD-TEA value was 738 J / m².Thus, the specific tensile strength of the nonwoven fabric according to the first embodiment of the invention is more than 80% greater in the MD direction and in the CD direction than the corresponding tensile strength of the reference nonwoven fabric, which was produced from monocomponent filaments of the first polypropylene component and otherwise under the same conditions. Furthermore, the total TEA value of the nonwoven fabric according to the invention is more than 280% greater than the corresponding total TEA value of the reference nonwoven fabric, which was produced from monocomponent filaments of the first polypropylene component and otherwise under the same conditions. Exemplary embodiment 2 according to the invention:

[0054] In a second embodiment according to the invention, a nonwoven fabric was produced from bicomponent filaments with a centric or symmetrical core-sheath configuration. The nonwoven fabric was manufactured as a three-layer nonwoven with three identical layers. The bicomponent filaments were produced as continuous filaments using the spunbond process in a device or method for producing nonwovens or spunbond nonwovens as described above, wherein three spinnerets or spinnerets connected in series, each with its component arranged below, were used above a single lay-up screen belt. The core component of the bicomponent filaments was formed by a first polypropylene component, which consisted of, or essentially consisted of, a first base polypropylene.For the sheath component, a second polypropylene component was used, consisting essentially of a second base polypropylene. The bicomponent filaments were produced with a filament fineness of 1.4 to 1.5 denier. The nonwoven fabric was end-worked using a calender at a surface temperature of 160 °C for the engraving roll and 150 °C for the S-roll, resulting in an embossed area of ​​18.1% with rounded consolidation bumps and a density of 49.9 g / cm². A homopolypropylene with a melt flow rate of 25 g / 10 min was used as the first polypropylene component, or first base polypropylene. This first polypropylene component, or first base polypropylene, formed the core of the bicomponent filaments in the second embodiment of the invention. The homopolypropylene "Borealis HG 475FB" was used here as the first polypropylene component, or first base polypropylene.This involves a Ziegler-Natta polypropylene polymerized with a Ziegler-Natta catalyst. A homopolypropylene with a melt flow rate (MFR) of 35 g / 10 min was used as the second polypropylene component, or second base polypropylene. This second polypropylene component, or second base polypropylene, formed the sheath of the core-sheath bicomponent filaments. The homopolypropylene "Exxon 3155" was used for this second polypropylene component, or second base polypropylene. This is a Ziegler-Natta polypropylene polymerized with a Ziegler-Natta catalyst. The mass ratio of the first polypropylene component to the mass of the second polypropylene component was 70:30. The speed of the laying device, or the speed of the laying screen belt, was 620 m / min. The basis weight of the resulting nonwoven fabric was 13 g / m².The melting point difference between the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component was 0 °C and approximately 0 °C, respectively. Both polypropylenes have a melting point of 161 °C. The specific tensile strength of the nonwoven fabric in the MD direction was 2.8 N / 5 cm per g / m², and the specific tensile strength of the nonwoven fabric in the CD direction was 1.5 N / 5 cm per g / m². The total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric was 513 J / m². The MD-TEA value of the nonwoven fabric was 311 J / m², and the CD-TEA value of the nonwoven fabric was 202 J / m². Comparison nonwoven fabric 2:

[0055] A comparison nonwoven fabric 2 was produced from monocomponent filaments of the first polypropylene component described above for the second embodiment according to the invention, and otherwise under the same conditions as the second embodiment according to the invention. The resulting comparison nonwoven fabric 2 was identical to the nonwoven fabric of the second embodiment according to the invention and described above with respect to its titer and basis weight. The comparison nonwoven fabric 2 exhibited a specific tensile strength in the MD direction of 2.6 N / 5 cm per g / m² and in the CD direction of 1.3 N / 5 cm per g / m². The comparison nonwoven fabric had a total TEA value of 393 J / m², wherein the MD-TEA value was 246 J / m² and the CD-TEA value was 147 J / m².Thus, the specific tensile strength of the nonwoven fabric according to the second embodiment of the invention is more than 7% higher in the MD direction and more than 15% higher in the CD direction than the corresponding tensile strength of the reference nonwoven fabric, which was produced from monocomponent filaments of the first polypropylene component and otherwise under the same conditions. Furthermore, the total TEA value of the nonwoven fabric according to the invention (second embodiment of the invention) is more than 30% higher than the corresponding total TEA value of the reference nonwoven fabric, which was produced from monocomponent filaments of the first polypropylene component and otherwise under the same conditions.

[0056] The invention is based on the finding that the nonwoven fabric according to the invention, made from multi-component filaments, in particular bi-component filaments, is characterized by a surprisingly high strength or tensile strength compared to methods known from practice. Due to the similarity of the base polypropylene of the first polypropylene component and the base polypropylene of the second polypropylene component, at least with regard to some properties—especially with regard to the melting point and the polymerization catalyst—and the resulting properties, multi-component or bi-component filaments are provided that essentially mimic a mono-component filament—at least with regard to certain properties—and the properties of the filaments can be more precisely tailored compared to mono-component filaments.This results in nonwovens with very high tensile strength values ​​in the MD direction and / or in the CD direction, which reliably meet all requirements for strength, especially tensile strength. It should also be emphasized that the measures according to the invention are not very complex and that the nonwoven fabric and the process according to the invention are very economical.

[0057] The invention will now be explained in more detail with reference to a drawing that illustrates only one embodiment. The drawing shows, in schematic representation: Fig. 1 a vertical section through a device for producing a nonwoven fabric or a nonwoven layer of a nonwoven fabric according to the invention. Fig. 2 a cross-section through a filament of a nonwoven fabric according to the invention with a centric or symmetrical core-sheath configuration.

[0058] The Fig. 1shows a device for producing a nonwoven fabric 8 according to the invention or a nonwoven layer of a nonwoven fabric 8 according to the invention.

[0059] If, according to a preferred embodiment, the nonwoven fabric has at least two, preferably at least three, in particular three, layers of nonwoven fabric, at least two, preferably at least three or three, spinnerettes 6 or spinner beams, respectively, are connected one after the other with the components arranged below them in the conveying direction F of the depositing screen belt 7 or in the machine direction (MD), and the three layers of nonwoven fabric are preferably laid on top of each other on a single depositing screen belt 7 and preferably combined to form a laminate.

[0060] The device preferably comprises, and in the exemplary embodiment, a spinning unit in the form of a spinnerette 6 or a spinning beam for spinning filaments or continuous filaments 1 for a nonwoven fabric 8 or a nonwoven layer of a nonwoven fabric 8. The continuous filaments 1 spun by the spinnerette 6 are preferably, and in the exemplary embodiment, fed into a cooling device 12 with a cooling chamber 13. Preferably, and in the exemplary embodiment, air supply chambers 14, 15 are arranged one above the other on two opposite sides of the cooling chamber 13. Air of different temperatures is expediently introduced into the cooling chamber 13 from the superimposed air supply chambers 14, 15. Preferably, and in the exemplary embodiment, a monomer extraction device 16 is arranged between the spinnerette 6 and the cooling device 12.This monomer extraction device 16 can remove interfering gases that occur during the spinning process from the apparatus.

[0061] As recommended, and in the exemplary embodiment, a drawing device 17 for drawing the continuous filaments 1 is connected downstream of the cooling device 12 in the filament flow direction. Advantageously, and in the exemplary embodiment, the drawing device 17 has an intermediate channel 18 that connects the cooling device 12 to a drawing shaft 19 of the drawing device 17. Preferably, and in the exemplary embodiment, the assembly consisting of the cooling device 12 and the drawing device 17, or the assembly consisting of the cooling device 12, the intermediate channel 18, and the drawing shaft 19, is designed as a closed unit, and apart from the supply of cooling air to the cooling device 12, no further air is supplied to this unit from the outside.

[0062] Advantageously, and in the exemplary embodiment, a diffuser 20 is connected to the drawing device 17 in the direction of filament flow, through which the continuous filaments 1 are guided. After passing through the diffuser 20, the continuous filaments 1 are preferably, and in the exemplary embodiment, deposited in a depositing area on a depositing device designed as a depositing screen belt 7. The depositing screen belt 7 is advantageously, and in the exemplary embodiment, designed as an endlessly circulating depositing screen belt 7. It is within the scope of the invention that the depositing screen belt 7 is air-permeable, so that process air can be extracted from below through the depositing screen belt 7. Preferably, and in the exemplary embodiment, the device has a consolidation device designed as a calender 11 for final consolidation of the nonwoven fabric 8 in the conveying direction F of the nonwoven or in the machine direction MD behind the depositing area of ​​the continuous filaments 1.Preferably, and in the exemplary embodiment, the calender 11 has two calender rolls 9, 10. It is possible that one of the calender rolls 9, 10, in particular also called the engraving roll, has a complementary embossing pattern of embossing elements on its outer surface, with which an embossing pattern of bonding points, in particular bonding points, can be introduced into the nonwoven fabric 8. The second calender roll, in particular also called the S-roll, can, according to a preferred embodiment, have a smooth outer surface. This is shown in the . Fig. 1 not shown in detail.

[0063] The Fig. 2Figure 1 shows a cross-section through a continuous filament 1 with a centric or symmetrical core-sheath configuration. It is a bicomponent filament 1 with a first polypropylene component 2, which preferably, and in the exemplary embodiment, consists of a first base polypropylene, or essentially consists of a first base polypropylene, and which forms the core 4 of the bicomponent filament 1. The bicomponent filament 1 further comprises a second polypropylene component 3, which preferably, and in the exemplary embodiment, consists of a second base polypropylene, or essentially consists of a second base polypropylene, and forms the sheath 5 of the bicomponent filament 1. The base polypropylene of the first polypropylene component 2 and the base polypropylene of the second polypropylene component 3 may preferably, and in the exemplary embodiment, each be polymerized with a metallocene catalyst and have the same or the same properties.They have essentially the same melting point, and advantageously, and in the exemplary embodiment, the base polypropylene of the first polypropylene component 2 and the base polypropylene of the second polypropylene component 3 are different polypropylenes. The ratio of the mass of the first polypropylene component 2, which forms the core 4 of the bicomponent filament 1, to the mass of the second polypropylene component 3, which forms the sheath 5 of the bicomponent filament 1, may advantageously, and in the exemplary embodiment, be approximately 75:25.

Claims

1. Nonwoven fabric made of continuous filaments (1), wherein the filaments (1) are multi-component filaments, in particular bi-component filaments, and comprise at least a first polypropylene component (2) comprising a base polypropylene and at least a second polypropylene component (3) comprising a base polypropylene, wherein the melting point difference between the base polypropylene of the first polypropylene component (2) and the base polypropylene of the second polypropylene component (3) is less than 5 °C, preferably less than 4 °C, more preferably less than 3 °C, more preferably less than 2 °C and most preferably less than 1 °C, and wherein the base polypropylene of the first polypropylene component (2) and the base polypropylene of the second polypropylene component (3) were polymerized with a catalyst from the same class of catalysts and were preferably each polymerized with a metallocene catalyst or each with a Ziegler-Natta catalyst.

2. Nonwoven fabric according to claim 1, wherein the filaments (1) are multi-component filaments or bi-component filaments with core-sheath configuration, in particular with centric or symmetrical core-sheath configuration, and wherein preferably the first polypropylene component (2) forms the core (4) and the second polypropylene component (3) forms the sheath (5) of the filaments (1).

3. Nonwoven fabric according to one of claims 1 or 2, wherein the first polypropylene component (2) and / or the second polypropylene component (3) comprises the respective base polypropylene to a proportion of at least 70 wt.%, preferably at least 80 wt.%, preferably at least 85 wt.%, particularly preferably at least 90 wt.% and most preferably at least 92 wt.%.

4. Nonwoven fabric according to any one of claims 1 to 3, wherein the first polypropylene component (2) and / or the second polypropylene component (3) consists of the respective base polypropylene or consists substantially of the respective base polypropylene.

5. Nonwoven fabric according to any one of claims 1 to 4, wherein the first polypropylene component (2) and / or the second polypropylene component (3) is / are a mixture or a blend of the respective base polypropylene and at least one additive.

6. Nonwoven fabric according to any one of claims 1 to 5, wherein different polypropylenes are used as the base polypropylene of the first polypropylene component (2) and as the base polypropylene of the second polypropylene component (3).

7. Nonwoven fabric according to one of claims 1 to 5, wherein the same polypropylene is used as the base polypropylene of the first polypropylene component (2) and as the base polypropylene of the second polypropylene component (3), and wherein at least one polypropylene component (2, 3), preferably at least the second polypropylene component (3), is a mixture or a blend of the base polypropylene and at least one additive.

8. Nonwoven fabric according to any one of claims 5 to 7, wherein the proportion of the at least one additive in the first polypropylene component (2) and / or in the second polypropylene component (3) is 0.1 to 30.0 wt.%, preferably 0.2 to 20.0 wt.%, more preferably 0.5 to 15.0 wt.%, more preferably 1.0 to 10.0 wt.%, more preferably 1.5 to 9.0 wt.%, more preferably 2.0 to 8.0 wt.%, for example 3.0 to 6.0 wt.%, and wherein the at least one additive is expediently an additive polypropylene.

9. Nonwoven fabric according to any one of claims 1 to 8, wherein the base polypropylene of the first polypropylene component (2) and the base polypropylene of the second polypropylene component (3) have the same or substantially the same melting point.

10. Nonwoven fabric according to any one of claims 1 to 9, wherein the melt flow rate (MFR) of the second polypropylene component (3) is greater than the melt flow rate (MFR) of the first polypropylene component (2) and wherein the ratio of the melt flow rate (MFR) of the second polypropylene component (3) to the melt flow rate (MFR) of the first polypropylene component (2) is in particular 1.02 to 10, preferably 1.05 to 8, more preferably 1.1 to 6, more preferably 1.2 to 3, most preferably 1.3 to 2.2, for example 1.35 to 2.

0.

11. Nonwoven fabric according to any one of claims 1 to 10, wherein the ratio of the mass of the first polypropylene component (2) to the mass of the second polypropylene component (3) is 95:5 to 50:50, preferably 90:10 to 55:45, preferably 85:15 to 60:40, particularly preferably 85:15 to 65:35, most particularly preferably 85:15 to 70:30, for example 80:20 to 75:

25.

12. Nonwoven fabric according to any one of claims 1 to 11, wherein the base polypropylene of the first polypropylene component (2) and / or the base polypropylene of the second polypropylene component (3) and / or the at least one additional polypropylene is / are a homo-polypropylene or a polypropylene copolymer.

13. Nonwoven fabric according to one of claims 1 to 12, wherein the nonwoven fabric (8) is end-bonded, in particular thermally end-bonded, and preferably has an embossed pattern of bonding sites, in particular bonding points.

14. Nonwoven fabric according to any one of claims 1 to 13, wherein the nonwoven fabric (8) has a basis weight of 20 g / m² 2 up to 110 g / m² 2 , preferably of 25 g / m² 2 up to 85 g / m² 2 , preferably 30 g / m² 2 up to 75 g / m² 2 exhibits and wherein the specific tensile strength of the nonwoven fabric (8) in the MD direction is preferably 2.5 to 7.2 N / 5 cm per g / m² 2 , preferably 3.0 to 7.0 N / 5 cm per g / m 2 preferably 3.2 to 6.8 N / 5 cm per g / m 2 , particularly preferably 3.4 to 6.7 N / 5 cm per g / m 2 and especially preferred 3.5 to 6.5 N / 5 cm per g / m 2 is and / or wherein preferably the specific tensile strength of the nonwoven fabric (8) in the CD direction is 2.0 to 4.0 N / 5 cm per g / m² 2 , preferably 2.1 to 3.8 N / 5 cm per g / m 2 preferably 2.2 to 3.7 N / 5 cm per g / m 2 , particularly preferably 2.3 to 3.6 N / 5 cm per g / m 2 amounts.

15. Nonwoven fabric according to any one of claims 1 to 14, wherein the nonwoven fabric (8) has a basis weight between 1 g / m² 2 and 20 g / m² 2 , preferably of 2 g / m² 2 up to 19 g / m² 2 , preferably 5 g / m² 2 up to 18 g / m² 2 exhibits and wherein the specific tensile strength of the nonwoven fabric (8) in the MD direction is preferably 1.5 to 4.5 N / 5 cm per g / m² 2 , preferably 1.7 to 4.0 N / 5 cm per g / m 2 preferably 1.8 to 3.8 N / 5 cm per g / m 2 , particularly preferably 2.0 to 3.5 N / 5 cm per g / m 2 and especially preferred 2.0 to 3.0 N / 5 cm per g / m 2 is and / or wherein preferably the specific tensile strength of the nonwoven fabric (8) in the CD direction is 1.0 to 2.5 N / 5 cm per g / m² 2 , preferably 1.1 to 2.0 N / 5cm per g / m 2 preferably 1.2 to 1.9 N / 5 cm per g / m 2 , particularly preferably 1.2 to 1.8 N / 5 cm per g / m 2 amounts.

16. Nonwoven fabric according to any one of claims 1 to 15, wherein the nonwoven fabric (8) has an embossed pattern of binding sites, in particular binding points, and wherein the proportion of the pore volume in the area of ​​a binding site is 1.0% to 12.0%, preferably 1.5% to 10.0%, preferably 2.0% to 7.0%, particularly preferably 2.5% to 6.5%.

17. Nonwoven fabric according to any one of claims 1 to 16, wherein the tensile strength and / or the specific tensile strength of the nonwoven fabric (8) in the MD direction and / or in the CD direction is greater than 4%, in particular greater than 6%, preferably greater than 10%, preferably greater than 15%, and particularly more preferably greater than 20%, than the corresponding tensile strength and / or the corresponding specific tensile strength of a comparison nonwoven fabric made from monocomponent filaments of the first polypropylene component (2) or the second polypropylene component (3) and otherwise under the same conditions.

18. Nonwoven fabric according to any one of claims 1 to 17, wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric (8) is at least 200 J / m² 2 , preferably at least 300 J / m² 2 , preferably at least 400 J / m² 2 , preferably at least 500 J / m 2 amounts.

19. Nonwoven fabric according to any one of claims 1 to 18, wherein the total TEA value (MD-TEA + CD-TEA) of the nonwoven fabric (8) is greater than 5%, preferably more than 10%, preferably more than 15%, particularly preferably more than 20%, and most preferably more than 25% than the corresponding total TEA value (MD-TEA + CD-TEA) of a reference nonwoven fabric produced from monocomponent filaments of the first polypropylene component (2) or the second polypropylene component (3) and otherwise under the same conditions.

20. Nonwoven fabric according to any one of claims 1 to 19, wherein the filaments have a denier of less than 2.3 den, preferably less than 2.1 den, preferably less than 1.9 den and particularly preferably a denier of 1.0 to 2.2 den, most preferably of 1.2 to 2.0 den, for example of 1.4 to 1.8 den.

21. Method for producing a nonwoven fabric according to one of claims 1 to 20, wherein filaments (1) are produced with at least one spinning device, in particular with at least one spinnerette (6), and are deposited on at least one depositing device, in particular on at least one depositing screen belt (7), to form the nonwoven fabric (8).

22. Method according to claim 21, wherein the nonwoven fabric (8) is end-strengthened with at least one consolidation device, in particular with at least one calender roll (9), and wherein the temperature, in particular the surface temperature, of the at least one consolidation device, in particular the at least one calender roll (9), is preferably 120 °C to 180 °C, preferably 130 °C to 175 °C, preferably 140 °C to 170 °C, very preferably 145 °C to 165 °C.

23. Method according to claim 22, wherein the temperature, in particular the surface temperature, of the at least one solidification device, in particular the at least one calender roll (9), is at least 1 °C, preferably at least 2 °C, preferably at least 3 °C, particularly preferably at least 4 °C, most preferably at least 5 °C lower than the melting point of the base polypropylene of the second polypropylene component (3) and / or the melting point of the base polypropylene of the first polypropylene component (2).

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