DE102021102287B3 - Spunbonded nonwoven laminate and method of making a spunbonded nonwoven laminate - Google Patents

Abstract

Spunbond laminate with at least two spunbond layers, wherein at least one spunbond layer has crimped continuous filaments. The crimped continuous filaments are multi-component filaments, in particular bi-component filaments with a first component based on polypropylene and a second component based on polypropylene. The specific density ϱ [g/cm3] of the spunbonded nonwoven laminate is dependent on the basis weight of the spunbonded nonwoven laminate below a limit density ϱG, which is defined by the following equation:ϱG=91cm×basis weightgcm2+0.0393gcm3

Description

The invention relates to a spunbonded nonwoven laminate having at least two spunbonded nonwoven layers, wherein at least one spunbonded nonwoven layer has crimped continuous filaments or consists or essentially consists of crimped continuous filaments, the crimped continuous filaments being multicomponent filaments, in particular bicomponent filaments. The invention further relates to a method for producing a spunbonded nonwoven laminate. - It is within the scope of the invention that the continuous filaments are continuous filaments made of thermoplastic material. Endless filaments differ from staple fibers, which have much shorter lengths of, for example, 10 mm to 60 mm, because of their quasi-endless length.

Spunbonded nonwoven laminates of the type described above and corresponding processes for producing such spunbonded nonwoven laminates are known from the prior art and from practice in various embodiments. Nonwovens or nonwoven laminates with a large thickness and the lowest possible mass per unit area are required for many applications. A large thickness is usually achieved by using crimped or wavy filaments (crimped filaments). In this case, spirally crimped filaments (spiral or helical crimp) are preferred. Multi-component filaments or bi-component filaments are used to produce crimped or crimped filaments. In order to achieve crimping, it is sufficient if the two components of bicomponent filaments differ in the breadth of the molar mass distribution. Other differences (viscosity, melting point, generally different solidification processes) or combinations thereof also result in crimping. The maximum crimp that can be achieved for a specific recipe can often only be used in slow single beam processes to produce individual spunbonded nonwovens in all forms. In the case of the multi-beam process for the continuous production of a plurality of layers of spunbonded nonwovens, this crimping is often too strong and an undesirable inhomogeneous deposit or a deposit with undesirably reduced dimensional stability results. Up until now, if a compromise was sought between high thickness and satisfactory filament deposit in multi-beam systems, this was usually at the expense of thickness. In the case of three-beam systems and thus a corresponding triple production speed for the production of fleece laminates with basis weights between 20 and 25 g/m ² , for example, a reduction to half or two thirds of the thickness of an individual layer is not unusual. In the case of multi-beam systems, the quality of the filing could be improved by using finer filaments. However, with finer filaments (more cabin pressure in the cooling cabin, more stretching air during stretching, less throughput), the mixtures known from the prior art typically show a reduction in the web thickness. The advantages of better filing and productivity cannot be combined with a high thickness here.

Fine fiber nonwovens are from the European patent EP 3 521 495 B1 known to the applicant. These fine-fiber fleeces have good coverage and high-quality placement and are characterized by a soft, homogeneous surface. In the case of multi-beam applications, however, the thickness also leaves a lot to be desired.

Multi-component filaments or bi-component filaments with a side-by-side configuration or with an eccentric core-sheath configuration are used in particular to produce sufficient crimp and a high thickness. The provision of a high thickness is usually associated with a relatively high basis weight of the nonwoven. This applies on the one hand to single-layer nonwovens, but in particular to multi-beam nonwovens produced in multi-beam systems.

The creation of several layers means that each layer has to be compacted or pre-consolidated to a greater extent in order not to damage the placement of these layers when the later beams pass through, but also that the first layers are additionally further compacted when the next layers are laid and thus compared accordingly good thicknesses that can be achieved in individual layers, the thickness of the spunbonded nonwoven laminate is also significantly reduced. Especially in the case of multi-beam systems of, for example, three or more beams, there is a conflict of objectives with regard to achieving a high thickness with a simultaneously low basis weight, and the solution to this conflict of objectives has hitherto presented the person skilled in the art with insoluble problems. Until now, reaching a target fleece thickness has generally led to a disproportionate increase in the mass per unit area of the fleece layer or fleece laminate or to a thick laminate with an inhomogeneous placement. This also results in an undesirably high use of material and thus high costs.

A high thickness with the lowest possible mass per unit area is therefore desirable. It must also be taken into account that such a spunbonded nonwoven laminate must meet the requirements in terms of softness, strength and, in particular, dimensional stability. Adequate strength and most importantly one out Sufficient dimensional stability are required for further processing. The desired properties are achieved in laminates known from the prior art by reinforcement layers, for example fleece layers without crimps or fleece layers with reduced crimps, or by combining a stable fine-fiber fleece layer (e.g. with filaments under 1.5 denier titre) with denser ones Network and medium crimp with thicker batt layers with fibers of normal denier (e.g. 1.7 to 2 denier) and with larger crimp. However, the basis weight of the laminate is relatively high.

The invention is based on the technical problem of specifying a spunbonded nonwoven laminate of the type mentioned at the outset, which has a greater thickness compared to the nonwovens known from practice or from the prior art, with a substantially constant use of material - especially in the case of production in multi-beam systems - and at the same time has an optimal softness, a high strength and in particular a high dimensional stability. The invention is also based on the technical problem of specifying a corresponding method for producing such a spunbonded nonwoven laminate.

To solve this technical problem, the invention teaches a spunbonded nonwoven laminate with at least two spunbonded layers, wherein at least one spunbonded layer has crimped continuous filaments or consists or essentially consists of crimped continuous filaments, the crimped continuous filaments being multicomponent filaments, in particular bicomponent filaments with a first component based on polypropylene and a second component based on polypropylene and where the specific density ϱ [g/cm ³ ] of the spunbonded nonwoven laminate is below a limit density ϱ _G as a function of the mass per unit area of the spunbonded nonwoven laminate, which is defined by the following equation: $${\varrho }_G=9\frac{1}{cm}\times fl\ddot{a}cHenmasse\frac{\mathrm{<figure-callout\; id="2"\; label="G\; c\; m"\; filenames="DE102021102287B3\_0007.png,DE102021102287B3\_0008.png"\; state="\{\{state\}\}">G</figure-callout>}}{c{m}^{}}+0.0393\frac{\mathrm{<figure-callout\; id="3"\; label="G\; c\; m"\; filenames="DE102021102287B3\_0010.png"\; state="\{\{state\}\}">G</figure-callout>}}{c{m}^{}}$$

The specific limiting density ϱ _G is therefore linearly dependent on the mass per unit area of the spunbonded nonwoven laminate.

A spunbonded nonwoven laminate according to the invention can consist of only two spunbonded nonwoven layers, with at least one of these spunbonded nonwoven layers having the crimped continuous filaments. However, it is also within the scope of the invention for a spunbonded nonwoven laminate according to the invention to have more plies or nonwoven layers and, for example, to comprise two or more spunbonded nonwoven layers with crimped continuous filaments and/or two or more spunbonded nonwoven layers with filaments with little or no crimping. It is essential within the scope of the invention that there are at least two spunbonded nonwoven layers in the laminate, of which at least one spunbonded nonwoven layer has the crimped continuous filaments.

A highly recommended embodiment of the invention is characterized in that the first component of the multicomponent filaments or bicomponent filaments consists or essentially consists of a polypropylene mixture or consists or essentially consists of a polypropylene copolymer (CoPP). The expression “essentially consists” means in particular that the first component consists of at least 90% by weight, preferably at least 95% by weight and preferably at least 98% by weight of the polypropylene mixture or of the polypropylene copolymer exists. This statement “essentially consists” takes into account in particular the fact that, in addition to the substance mentioned, additives and the like can also be contained in the first component. These additives are in particular active substances such as paints, plasticizers/lubricants, surface-active substances, nucleating agents or fillers such as chalk. The term "polypropylene mixture" means in particular the mixture of two or more homopolypropylenes or the mixture of at least one homopolypropylene with at least one polypropylene copolymer or the mixture of two or more polypropylene copolymers. Polypropylene copolymer also means, in particular, corresponding random copolymers.

It is within the scope of the invention that the second component of the multi-component filaments or bi-component filaments consists or essentially consists of a polypropylene. The expression “essentially” means in particular that the second component consists of at least 90% by weight, preferably at least 95% by weight and preferably at least 98% by weight of the polypropylene. In the context of the invention, the fact that the second component consists or essentially consists of a polypropylene means that the second component consists or essentially consists of a homopolypropylene or consists or essentially consists of a polypropylene copolymer. In principle, the second component could also consist or essentially consist of a polypropylene mixture, in which case the definition given for the polypropylene mixture in particular then applies applies to the first component. Here, too, additives can be contained as in the first component, with the type and proportion of the additives being able to differ between the components.

A particularly preferred embodiment of the invention is characterized in that the at least one spunbonded nonwoven layer with crimped continuous filaments is filaments with a titer of up to 2 denier, preferably with a titre of less than 2 denier, preferably with a titer of less than 1.5 denier, particularly preferably from 1 to 1 .7 denier and most preferably from 1.2 to 1.7 denier. In this respect, the invention is based on the knowledge that the solution to the technical problem is achieved by sufficient crimping of the filaments with finer filaments, these finer filaments enabling a stable network of the deposit and thus a dimensionally stable product.

A very preferred embodiment of the invention is characterized in that the crimped continuous filaments of the at least one spunbonded nonwoven layer with crimped continuous filaments have a core-sheath configuration and particularly preferably have an eccentric core-sheath configuration. The first component of the multi-component filaments or bi-component filaments expediently forms the sheath component and the second component forms the core component. However, it is also within the scope of the invention for the at least one spunbonded nonwoven layer having crimped continuous filaments to have the filaments in a side-by-side configuration. One side of the filaments is formed by the first component and the other side by the second component.

A highly recommended embodiment of the invention is characterized in that at least 25% of all filaments or continuous filaments of the laminate according to the invention are crimped continuous filaments with a core-sheath configuration, in particular with an eccentric core-sheath configuration. The protruding proportion of filaments (fiber proportion) is expediently determined as follows: the spunbonded nonwoven laminate is cut over a length of at least 10 mm and an SEM image is taken of the cut surface and evaluated. The fiber content of the filament type in question corresponds to the number of corresponding filaments in the field of view, based on all filaments in the cut surface in the field of view.

It is within the scope of the invention that, in the case of the crimped continuous filaments with an eccentric core-sheath configuration, the sheath of the filaments—seen in the filament cross section—over at least 20%, in particular over at least 25%, preferably over at least 30%, preferably over at least 35% and particularly preferably has a constant thickness D or a substantially constant thickness D over at least 40% of the filament circumference.

The thickness of the jacket in the region of its constant or essentially constant thickness D is expediently 0.1 to 4 μm, preferably 0.1 to 3 μm, preferably 0.1 to 2 μm and very preferably 0.1 to 0.9 μm . It is recommended that the thickness D is at least 100 nm and that the thickness varies locally by up to a maximum of 400 nm, in particular up to a maximum of 300 nm, preferably up to a maximum of 200 nm from the average thickness in the constant thickness range or in the essentially constant thickness range differs.

A very preferred embodiment of the invention is characterized in that the laminate according to the invention has at least three spunbonded nonwoven layers, with at least one spunbonded nonwoven layer with crimped continuous filaments - in particular with crimped continuous filaments with an eccentric core-sheath configuration - being arranged on an outside of the laminate and that preferably the Denier of the continuous filaments of this spunbonded nonwoven layer is up to 2 deniers, preferably less than 2 deniers, particularly preferably less than 1.5 deniers, in particular 1 to 1.7 deniers and very preferably 1.2 to 1.7 deniers.

A highly recommended embodiment of the invention is characterized in that the spunbonded nonwoven laminate according to the invention has a basis weight in the range from 10 to 40 g/m ² , in particular in the range from 12 to 35 g/m ² , preferably in the range from 13 to 30 g/m ² , preferably in the range of 14 to 25 g/m ² and very preferably in the range of 15 to 22 g/m ² .

It is within the scope of the invention that the first component of the multi-component filaments or bi-component filaments is at least one polypropylene copolymer (CoPP) or has a polypropylene copolymer, with this first component preferably having a proportion of the comonomer of 1 to 7 wt. -%, preferably from 1.5 to 5% by weight. It has been shown that the softness of the laminate according to the invention can be improved by this embodiment. Preferably, a corresponding spunbonded nonwoven layer with these crimped continuous filaments on an outside or on a surface surface of the spunbonded laminate according to the invention arranged. Here, the crimped continuous filaments of this spunbond nonwoven layer on the surface of the laminate are preferably crimped continuous filaments having an eccentric core-sheath configuration, and the aforementioned polypropylene copolymer is contained in the sheath component of the crimped continuous filaments.

A particularly recommended embodiment of the invention is characterized in that the first and the second component of the multicomponent filaments or bicomponent filaments have different melt flow rates (MFI) and that in the case of continuous filaments with a core-sheath configuration, the second component forming the core component preferably has a higher melt flow rate as the first component constituting the sheath component. It is within the scope of the invention that the ratio of the melt flow rate of the second component - in particular the core component - to the melt flow rate of the first component - in particular the sheath component - is 0.9 to 2.5 and preferably 1 to 2.2. In the context of the invention, the melt flow rate is preferably measured according to ISO 1133 in g/10 min under the conditions 230° C. and 2.16 kg.

A particularly proven embodiment of the invention is characterized in that the ratio of the polydispersity index (PI) of the first component - in particular the sheath component - to the polydispersity index (PI) of the second component - in particular the core component - is 0.9 to 1.4, in particular 1 to 1.35. It is recommended that the first component--particularly the shell component--has a broader molar mass distribution than the second component--particularly the core component. The polydispersity index is the quotient of the mass average molar mass M _w and the number average molar mass M _n (PI=M _w /M _n ). The mean molar masses are measured in particular by gel permeation chromatography (GPC), preferably in accordance with ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D6474-12. The polydispersity index (PI=M _w /M _n ) is typically measured for pure polymers. For the sake of simplicity, it is assumed here that the polydispersity index of a polymer mixture is made up of the polydispersity indices of the individual raw materials according to their proportions. The polydispersity index of a polymer mixture made from polymers A and B is then calculated using the following formula: $$\text{PI}\left(\text{Mixture A}+\text{B}\right)=\text{Share A}\times \text{PI}\left(\text{A}\right)+\text{Share B}\times \text{PI}\left(\text{B}\right).$$

A polymer mixture with 60% A and 40% B then has a polydispersity index PI (A + B) = 0.6 x PI (A) + 0.4 x PI (B).

According to a recommended embodiment of the invention, the melting temperature of the first component - in particular the shell component - is lower than the melting temperature of the second component - in particular the core component - and the melting temperature difference is expediently 0 to 20 °C, preferably 1 to 18 °C and preferably 2 up to 16 °C. The invention is based on the knowledge that in this embodiment there is less effort involved in the thermal bonding of the fleece layers and/or the fleece laminate, since the jacket component melts more easily than the core component due to the lower melting temperature. It is recommended that the melting temperatures in the context of the invention are measured by DSC (differential scanning calorimetry) in accordance with ISO 11357-3.

A preferred embodiment of the invention is characterized in that the second component or the second component used as the core component has at least one lubricant, preferably at least 1,000 ppm (based on the entire filament) of at least one lubricant. The invention is based on the finding that the softness of the spunbonded nonwoven laminate can be improved in this way, in particular if the nonwoven layer in question is arranged on a surface or on an outside of the laminate. The admixture in the core component reduces the contamination of the spunbonded layer by evaporating lubricant.

To solve the technical problem, the invention also teaches a method for producing a spunbonded nonwoven laminate with at least two spunbonded nonwoven layers, wherein at least one spunbonded nonwoven layer is produced with crimped continuous filaments, the crimped continuous filaments being multi-component filaments, in particular bi-component filaments with a first component based on polypropylene and a second component are based on polypropylene,
wherein at least one spunbonded nonwoven layer is compacted or pre-consolidated by means of at least one hot roller and/or by means of at least one calender roller and/or by at least one hot air oven, wherein the spunbonded nonwoven laminate is finally consolidated by means of at least one calender roller
and wherein the laminate is produced with the proviso that the specific density ϱ [g/cm ³ ] of the spunbonded nonwoven laminate as a function of the mass per unit area of the spunbonded nonwoven laminate is below a limit density ϱ _G which is defined by the following equation: $${\varrho }_G=9\frac{1}{cm}\times fl\ddot{a}cHenmasse\frac{\mathrm{<figure-callout\; id="2"\; label="G\; c\; m"\; filenames="DE102021102287B3\_0007.png,DE102021102287B3\_0008.png"\; state="\{\{state\}\}">G</figure-callout>}}{c{m}^{}}+0.0393\frac{\mathrm{<figure-callout\; id="3"\; label="G\; c\; m"\; filenames="DE102021102287B3\_0010.png"\; state="\{\{state\}\}">G</figure-callout>}}{c{m}^{}}$$

It is within the scope of the invention that the at least one spunbonded nonwoven layer with crimped continuous filaments is compacted or pre-consolidated in the manner described. Furthermore, it is within the scope of the invention that at least two, preferably all spunbonded nonwoven layers of the spunbonded nonwoven laminate according to the invention are each compacted or pre-consolidated in the manner mentioned.

A particularly preferred embodiment of the method according to the invention is characterized in that the final consolidation is carried out with at least one calender roll which has an “open dot” engraving. The “open dot” engraving is characterized by an embossing area or pressing area of 8 to 15%, in particular 10 to 14% and preferably 11 to 13%. The figure density of the calender roll for the final consolidation is recommended to be below 35 figures per cm ² , in particular below 30 figures per cm ² and is preferably 18 to 28 figures per cm ² and preferably 20 to 28 figures per cm ² . The area of a is expediently 0.25 to 0.75 mm ² , in particular 0.3 to 0.7 mm ² , with compact figures (circles, rhombuses or ellipses with a length/width ratio below 2) being preferred. It is recommended that the center distance between two figures of the calender roll is between 0.9 and 2.5 mm, in particular between 1 and 2 mm. The engraving depth of the calender roll is preferably 0.4 to 1.0 mm, in particular 0.5 to 0.9 mm.

It is also within the scope of the invention that the coverage or opacity of the spunbonded nonwoven laminate according to the invention is improved by the addition of color. For this purpose, the color is dosed evenly in all layers of the laminate. It is also within the scope of the invention that color is metered only into special fleece layers. The color is dosed expediently in fleece layers with a more even deposit, so that the optical uniformity can be optimized for a given color component. The color can be introduced in particular into non-woven layers with less crimping of the filaments or in non-woven layers without crimping of the filaments or also in non-woven layers with a higher basis weight. In principle, layers with finer filaments are also possible.

The definition according to the invention of the specific density ϱ of the spunbonded nonwoven laminate below the limit density ϱ _G relates to the state of manufacture of the spunbonded nonwoven laminate according to the invention. Normally, however, in the processing chain between its production, further processing and packaging of the finished end product, the spunbonded nonwoven laminate will experience compression acting on the spunbonded nonwoven laminate in the thickness direction. It is within the scope of the invention that the laminate thickness then adjusts itself back again only up to a certain percentage. This percentage of the thickness of the spunbonded nonwoven laminate that does not return to the original laminate thickness after being subjected to compression is referred to as the compression set and represents a permanent deformation of the spunbonded nonwoven laminate. It is within the scope of the invention that the spunbonded nonwoven laminate according to the invention has a maximum compression set of 30%, in particular 20% and preferably 10%, so that the specific density ϱ of the spunbonded nonwoven--especially when the end product is in use--is a maximum of 30%, in particular a maximum of 20% and preferably a maximum of 10% above the limit density ϱ _G .

The compression set of the laminate according to the invention is expediently determined as follows: The spunbonded nonwoven laminate has an original thickness D ₁ , which is measured with a pressure of 0.5 kPa. The spunbonded nonwoven laminate is then loaded or compressed at 6 kPa for three days and then stored for three days without loading. After this time, the thickness D ₂ is measured. The compression set (DVR) is then calculated as follows: DVR = (D ₁ - D ₂ )/D ₁ . The measurement is repeated for at least five samples and then the average is determined as a DVR.

The density ϱ of a spunbonded nonwoven laminate according to the invention is preferably determined as follows: The proportion of air between the filaments of the laminate is neglected. The density then results from the quotient of the basis weight of the laminate/thickness of the laminate. The density of a spunbonded fabric with a basis weight of 50 g/m ² and a thickness of 0.2 mm is then 50/0.2=0.25 g/cm ³ .

It is within the scope of the invention that the spunbonded nonwovens used in the spunbonded nonwoven laminate according to the invention and in particular also the at least one spunbonded nonwoven layer with crimped endless filaments is produced by a spunbond process. A preferred spunbond process for the spunbonded nonwovens of the spunbonded nonwoven laminate according to the invention is described below. The continuous filaments for a spunbonded nonwoven or for a spunbonded nonwoven layer are spun by means of a spinneret or spinnerette and then cooled in a cooling device with a cooling chamber. It is within the scope of the invention for a monomer suction device to be arranged between the spinneret 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 stretching device for stretching the continuous filaments. The stretching device is recommended to have an intermediate channel which connects the cooling device to a stretching shaft of the stretching device. According to a particularly preferred embodiment of the invention, the unit consisting of the cooling device and the stretching device or the unit consisting of the cooling device, the intermediate channel and the stretching shaft is designed as a closed unit and, apart from the supply of cooling air in the cooling device, no further air is supplied to this unit from the outside .

At least one diffuser, through which the continuous filaments are guided, preferably follows the drawing device in the direction of filament flow. After passing through the at least one diffuser, the continuous filaments are expediently deposited on a depositing device, which is preferably designed as a depositing sieve belt. The storage sieve belt is recommended to be an endless revolving sieve belt. The deposit sieve belt is expediently designed to be air-permeable, so that process air can be sucked off from below through the deposit sieve belt. At least one suction device is expediently provided for sucking off the process air under the depositing sieve belt.

The invention is based on the finding that a high thickness and high softness can be achieved in a spunbonded nonwoven laminate according to the invention, with nevertheless sufficiently high strength and dimensional stability of the laminate. In addition, the filament deposit is characterized by a satisfactory quality and sufficient homogeneity. Compared to the methods known from the prior art, with the method according to the invention a greater thickness and greater softness can be achieved with virtually the same use of material, with the laminates being sufficiently strong and dimensionally stable. It should be emphasized that the advantages according to the invention can be achieved by relatively simple measures and thus at relatively low costs.

Examples:

The plastics or polymers used in the following exemplary embodiments are specified in more detail in Table 1 below. Here the individual polymers are marked with the letters A to G, which are used in the exemplary embodiments. In addition to the name of the manufacturer and the type of polymer, the melt flow rate MFR of the polymer is given in g/10 min in the fourth column and the melting point TM in degrees Celsius in the fifth column. The sixth column gives the number average molecular weight M _n and the seventh column gives the weight average molecular weight M _w . The eighth column relates to the centrifuge average molecular weight _Mz and the ninth column gives the polydispersity index PI= _Mw / _Mn . The quotient M _w /M _z of the mean molar masses can be found in the last column. The polymers A to G are used in the following examples. Table 1: polymer Manufacturer Name Type MFR g/10 min TM °C M _n M _w M _z M _w /M _n (PI) M _w /M _z A Moplen HP562T homopolypropylene 55 160 28000 152200 320100 5.4 2.1 B Exxon PP3155E5 homopolypropylene 35 159 30150 148500 307500 4.93 2.07 C Borealis HG475FB homopolypropylene 27 158 35800 166000 344000 4.6 2.07 D Moplen RP248R polypropylene copolymer 30 144 33600 152500 308000 4.54 2.02 E Moplen RP3386 polypropylene copolymer 30 144 33600 152500 308000 4.54 2.02 f Moplen RP348R polypropylene copolymer 25 148 28900 194750 569000 6.7 2.9 G Sabic PP511A homopolypropylene 25 161 36500 163500 340500 4.9 2.08

The following Tables 2 to 4 relate to bicomponent filaments suitable for the invention with the two components 1 and 2 based on polypropylene. The abbreviation PP here means a homopolypropylene and the abbreviation CoPP means a polypropylene copolymer. If different digits (1, 2 or 3) are appended, this indicates that they are different homopolypropylenes or different polypropylene copolymers. For example, PP1 and PP2 are two different homopolypropylenes. The homopolypropylenes and polypropylene copolymers were selected from Table 1 above.

The following should be noted for the assignment of the two components 1 and 2 of the bicomponent filaments in Tables 2 to 4 below: In the case of combinations of homopolypropylenes for components 1 and 2, the component with the narrower molecular weight distribution (or with the smaller polydispersity index PI) is the component 1. In the case of combinations of homopolypropylenes with polypropylene copolymers (CoPP), the homopolypropylene is component 1 and the propylene copolymer is component 2. In the case of combinations of polypropylene copolymers (CoPP/CoPP), component 2 is the broader component Molecular weight distribution (with the higher polydispersity index PI).

Bicomponent filaments with side-by-side configuration (S/S):

The bicomponent filaments of Table 2 with S/S configuration have a standard denier of 1.5 to 2.0. For components 1 and 2, the quotient of the melt flow rate of component 1 by the melt flow rate of component 2 is given in the third column. The quotient of the polydispersity index PI of component 2 to the polydispersity index PI of component 1 is listed in the fourth column. The absolute difference between the melting temperature of component 1 and the melting temperature of component 2 is given in the fifth column. Table 2: component MFF 1/2 PI 2/1 ΔT _m 1 - 2 1 2 PP1 PP1 + PP2 1.2 - 1.4 1.1 -1.3 < 5°C PP1 PP2 + PP3 1.2 - 1.4 1.1 - 1.3 < 5ºC PP1 CoPP1 / CoPP1 + CoPP2 0.9 - 1.2 1.1-1.3 10-15ºC PP1 CoPP1 + PP1/ CoPP1 + PP2 1.0 - 1.2 1.1 - 1.3 5-15ºC

Bicomponent filaments with eccentric core-sheath configuration (eC/S):

Table 3 below lists mixtures and parameters for bicomponent filaments according to the invention with an eC/S configuration and a standard titer greater than 1.5 denier. Table 3: component MFF 1/2 PI 2/1 ΔT _m 1 - 2 1 2 PP1 PP1 + PP2 0.9 - 1.5 1.1 -1.4 < 5°C PP1 PP2 + PP3 0.9 - 1.5 1.1 - 1.4 PP1 CoPP1 0.9 - 1.5 1.1 - 1.4 10 - 15°C PP1 CoPP1 + PP1 0.9 - 1.5 1.2 - 1.4 5 - 10 °C PP1 CoPP1 + PP2 0.9 - 1.5 1.2 - 1.4 5 - 10 °C PP1 CoPP1 + CoPP2 0.9 - 1.5 1.2 - 1.4 10 - 15 ° C

Table 4 below relates to bicomponent filaments according to the invention with an eccentric core-sheath configuration with a fine count of less than 1.5 denier. Table 4: component MFF 1/2 PI 2/1 ΔT _m 1 - 2 1 2 PP1 CoPP1 + PP2 1.5 - 2.2 1 - 1.2 5 - 10 °C PP1 CoPP1 1.5 - 2.2 1 - 1.2 5 - 15°C PP1 CoPP1 + CoPP2 1.5 - 2.2 1 - 1.2 5 - 15 °C PP1 PP1 +PP2 1.5 - 2.2 1 - 1.2 0 - 5 °C

The raw materials and the parameters or settings for the production of three-layer spunbonded nonwoven laminates are given in Tables 5 and 6 below. Each laminate is produced with a three-beam system with beams 1, 2 and 3. Preferably, each bar corresponds to one in the 1 illustrated device for the production of spunbond webs. Almost all nonwoven layers of the three-layer spunbonded nonwoven laminates have crimped bicomponent filaments with components 1 and 2. Only the middle or second fleece layer of samples 5 and 12 has monocomponent filaments. In the second line of the following tables, the combinations of raw materials and polymers are given for each sample. The raw materials A to G can be found in Table 1. In the third line of the following tables, the mass ratio of the two components to each other is given for the samples. The fourth line specifies the cabin pressure in the cooling chamber of the spunbond device used for the spunbond layer. The last line for the samples indicates the polymer throughput in the plant in kg/h/m. - Spinnerets with 6,800 capillaries/m were used to produce the fleece layers or the corresponding filaments. The three-ply laminates were each final consolidated with a calender roll with an "open dot" engraving.

Table 5 specifies eight laminate patterns of prior art three-ply spunbonded nonwoven laminates. Each layer of the three-layer laminate Samples 1 to 4 comprises crimped bicomponent filaments in a side-by-side configuration of 1.2 denier. In these samples 1 to 4, the polymer of each component of the bicomponent filaments was provided with 5% by weight of spinning aid. A Ziegler-Natta homopolypropylene with a melt flow rate of 1,200 g/10 min and a melting temperature of 158° C. was used here as the spinning aid.

Laminate samples 5 to 8 have filaments with a denier of 1.7. Almost all layers have crimped bicomponent filaments in side-by-side configuration. Only the second or middle layer of pattern 5 has monocomponent filaments without crimp and the first layer of pattern 8 has core-sheath bicomponent filaments without crimp. Table 5: Pattern: 1 bar 1 2 3 raw materials G/D G/D G/D mass ratio 70:30 50:50 60:40 cabin pressure 5800 6200 5600 Throughput kg/h/m 150 150 150 pattern: 2 bar 1 2 3 raw materials C/E C/E C/E mass ratio 50:50 50:50 50:50 cabin pressure 6500 6500 6500 Throughput kg/h/m 155 155 155 pattern: 3 bar 1 2 3 raw materials C/E C/E C/E mass ratio 50:50 50:50 50:50 cabin pressure 6500 6500 6500 Throughput kg/h/m 155 155 155 pattern: 4 bar 1 2 3 raw materials C/E C/E C/E mass ratio 50:50 50:50 50:50 cabin pressure 6500 6500 6500 Throughput kg/h/m 155 155 155 pattern: 5 bar 1 2 3 raw materials CD CD mass ratio 80:20 Mono - no frizz 70:30 cabin pressure 3800 4200 3800 Throughput kg/h/m 200 200 200 pattern: 6 bar 1 2 3 raw materials G/D G/D G/D mass ratio 90:10 60:40 50:50 cabin pressure 4000 4000 3800 Throughput kg/h/m 205 205 205 pattern: 7 bar 1 2 3 raw materials CD CD CD mass ratio 70:30 60:40 50:50 cabin pressure 4500 4500 4000 Throughput kg/h/m 250 250 250 pattern: 8 bar 1 2 3 raw materials G/D G/D G/D mass ratio 70:30 no frizz 70:30 70:30 cabin pressure 3800 4000 3800 Throughput kg/h/m 200 200 200

Table 6 below specifies four laminate samples (Sample 9 through Sample 12) of three-layer spunbonded nonwoven laminates according to the invention. Each layer of the three-ply spunbonded nonwoven laminates has crimped bicomponent filaments in an eccentric core-sheath configuration. Only the middle or second layer of sample 12 has monocomponent filaments without crimp. The filaments of samples 9 and 10 are 1.7 denier, the filaments of sample 11 are 1.35 denier and the filaments of sample 12 are 1.3 denier. For the raw materials specified in the second line, the first raw material specified forms the core component and the raw material mixture specified thereafter forms the sheath component of the bicomponent filaments. The mass ratio given in the third line refers to the mass ratio of core to cladding. The mass ratio given in the fourth line relates to the mass ratio of the constituents of the polymer mixture in the sheath component. Table 6: pattern: 9 bar 1 2 3 raw materials B/D+C B/D+C B/D+C mass ratio 85:15 80:20 70:30 Mass ratio D:C 70:30 80:20 80:20 cabin pressure 4000 4000 3800 Throughput kg/h/m 215 215 215 pattern: 10 bar 1 2 3 raw materials B/D+C B/D+C B/D+C mass ratio 90:10 85:15 80:20 Mass ratio D:C 60:40 70:30 80:20 cabin pressure 4000 4000 3800 Throughput kg/h/m 215 215 215 pattern: 11 bar 1 2 3 raw materials A/D+C A/D+C A/D+C mass ratio 90:10 70:30 70:30 Mass ratio D:C 60:40 75:25 75:25 cabin pressure 4000 5800 5500 Throughput kg/h/m 200 200 200 pattern: 12 bar 1 2 3 raw materials A/D+C only A A/D+C mass ratio 70:30 70:30 Mass ratio D:C 50:50 75:25 cabin pressure 5500 5800 5500 Throughput kg/h/m 200 200 200

Table 7 below summarizes the essential parameters for the nonwoven laminates of all samples 1 to 12. As already explained above, samples 1 to 8 are samples produced according to the prior art and samples 9 to 12 are samples Samples produced according to the teaching of the invention. The basis weight of the fleece laminate is given in the second column and the line speed or production speed in the third column. The fourth column gives the density of the fleece laminates in g/cm ³ . The last column lists the filament denier of the laminates. Table 7: template Basis weight (g/m ² ) line speed (m/min) Density (g/cm ³ ) denier 1 25 345 0.071 1.2 2 16.3 508 0.065 1.2 3 18.4 450 0.068 1.2 4 25.5 325 0.077 1.2 5 24.6 402 0.065 1.7 6 14.1 735 0.052 1.7 7 20.3 590 0.06 1.7 8th 12.9 830 0.056 1.7 9 23.5 450 0.053 1.7 10 20 550 0.057 1.7 11 20.3 500 0.053 1.35 12 17 590 0.047 1.3

In the 3 a diagram is shown for samples 1 to 12 in which the density (g/cm ³ ) of the entire spunbonded nonwoven laminate is plotted against the basis weight (g/m ² ) of the entire laminate. The samples 1 to 8 relating to the prior art show measurement points above the straight line according to the invention, which symbolizes the limit density ϱ _G . The parameter values of the samples 9 to 12 according to the invention are below the straight line or below the limit density. These spunbonded nonwoven laminates are distinguished by the advantages according to the invention, which are explained below.

Table 8 below shows the quotient of the melt flow rate of component 1 to component 2 for the first fleece layer of the fleece laminates according to samples 1 to 12, as well as the quotient of the polydispersity index of component 2 to component 1. Table 8: template PI ratio 2/1 MFI ratio 1/2 1 1.0 0.83 2 1.07 0.9 3 1.07 0.9 4 1.07 0.9 5 1.07 0.9 6 1.0 0.83 7 1.07 0.9 8th no ripple no ripple 9 1.24 1.37 10 1.2 1.36 11 1.09 2.13 12 1.05 2.12

Table 9 below shows the quotient of the melt flow rate of component 1 to component 2 for the three nonwoven layers of the nonwoven laminates according to samples 1 to 12, as well as the quotient of the polydispersity index of component 2 to component 1. Table 9: template Basis weight (g/m ² ) line speed (m/min) Density (g/cm ³ ) PI ratio 2/1 MFI ratio 1/2 1 25 345 0.071 1 / 1 / 1 0.83 / 0.83 / 0.83 2 16.3 508 0.065 1.07 / 1.07 / 1.07 0.9 / 0.9 / 0.9 3 18.4 450 0.068 1.07 / 1.07 / 1.07 0.9 / 0.9 / 0.9 4 25.5 325 0.077 1.07 / 1.07 / 1.07 0.9 / 0.9 / 0.9 5 24.6 402 0.065 1.07 / no frizz / 1.07 0.9 / no curl / 0.9 6 14.1 735 0.052 1 / 1 / 1 0.83 / 0.83 / 0.83 7 20.3 590 0.06 1.07 / 1.07 / 1.07 0.9 / 0.9 / 0.9 8th 12.9 830 0.056 no crimp / 1 / 1 no curl / 0.83 / 0.83 9 23.5 450 0.053 1.24 / 1.28 / 1.28 1.37 / 1.38 / 1.38 10 20 550 0.057 1.2 / 1.24 / 1.28 1.36 / 1.37 / 1.38 11 20.3 500 0.053 1.09 / 1.14 / 1.14 2.13 / 2.16 / 2.16 12 17 590 0.047 1.05 / no frizz / 1.14 2.12 / no crimp / 2.16

In the one relating to Tables 8 and 9 4 for the raw materials of the spunbonded nonwoven laminates or nonwoven layers, the quotient of the melt flow rate of component 1 to the melt flow rate of component 2 is plotted against the quotient of the polydispersity index of component 2 and the polydispersity index of component 1. In the diagram, the parameter points in the framed area correspond to bicomponent filaments according to the invention (samples 9 to 12). In contrast, the parameter points on the left below the horizontal straight line correspond to bicomponent filaments according to the prior art (samples 1 to 8). In the prior art, it is assumed that for MFR quotients above the horizontal line, the spinning stability becomes progressively worse. Furthermore, it is assumed for the first layer that for quotients of the polydispersity index to the right of the vertical straight line b) thick fleece layers can be achieved through relatively strong crimping, in which the degree of crimping can endanger the dimensional stability and thus also the machine runability. For the following bars 2 and 3, the area in which excessive crimping can jeopardize the placement quality begins to the right of the vertical dashed straight line c) in FIG 4 .

In contrast, in the framed area according to the invention, fine filaments with good crimping can be spun with good spinning stability, which enable a spunbonded nonwoven laminate with improved thickness and density according to the invention to be laid. The invention is based on the finding that area 1.1 in particular is to be preferred over area 1.2, since finer filaments with a good density of the laminate can be achieved more easily there (see also diagram according to 3 ).

In the in the diagram of 4 Marked direction 2, a gradual deterioration in the spinning stability is observed due to low viscosities (molecular weights of the polypropylenes that are too low) and thus a deterioration in the strength of the nonwoven laminates. - In accordance with the diagram 4 Marked direction 3, the spinning stability is lost due to the combination of molecular weight distributions that are too broad and differences in viscosity that are too great, and fine filaments or filaments with small deniers are therefore not possible. - Finally, in accordance with the diagram 4 Marked direction 4 no fine filaments can be spun, although higher densities can be achieved due to the larger quotient of the polydispersity index. The relatively strong crimping results in uneven and sensitive filament deposits. Filaments with too high a crimp are always in danger of being displaced in the deposition area by horizontal air movements. Due to the relatively high titer values, this effect is particularly pronounced here and cannot be controlled. This is in contrast to area 1.1 according to the invention with smaller titer values and a more stable network of filament deposits.

• 1 einen Vertikalschnitt durch eine Vorrichtung zur Erzeugung einer Spinnvlieslage eines erfindungsgemäßen Spinnvlieslamiantes,
• 2 einen Querschnitt durch ein bevorzugtes Endlosfilament mit exzentrischer Kern-Mantel-Konfiguration und
• 3 das Diagramm Dichte gegen Flächenmasse,
• 4 das Diagramm des Schmelzflussratequotienten gegen den Polydispersitätsindexquotienten.

The invention is explained in more detail below with reference to a drawing that merely shows an exemplary embodiment. They show in a schematic representation:

• 1 a vertical section through a device for producing a spunbonded nonwoven layer of a spunbonded nonwoven laminate according to the invention,
• 2 a cross section through a preferred continuous filament with eccentric core-sheath configuration and
• 3 the graph of density versus basis weight,
• 4 the plot of melt flow rate ratio versus polydispersity index ratio.

the 1 shows a device for producing a spunbonded nonwoven layer for the spunbonded nonwoven laminate according to the invention using the spunbond process. The at least one spunbonded nonwoven layer with crimped endless filaments for the spunbonded nonwoven laminate is preferably also produced with this device or with this method. The device has a spinnerette 1 for spinning endless filaments 2 for a spunbonded nonwoven layer of the spunbonded nonwoven laminate according to the invention. The continuous filaments 2 spun by the spinneret 1 are introduced into a cooling device 3 with a cooling chamber 4 . Preferably and in the exemplary embodiment, air supply cabins 5, 6 arranged one above the other are arranged on two opposite sides of the cooling chamber 4. Air of different temperatures is expediently introduced into the cooling chamber 4 from the air supply cabins 5, 6 arranged one above the other. Preferably and in the exemplary embodiment, a monomer suction device 7 is arranged between the spinneret 1 and the cooling device 3 . With this monomer suction device 7, interfering gases occurring during the spinning process can be removed from the device.

Recommended and in the exemplary embodiment, a stretching device 8 for stretching the endless filaments 2 is connected downstream of the cooling device 3 in the direction of filament flow. Expediently and in the exemplary embodiment, the stretching device 8 has an intermediate channel 9 which connects the cooling device 3 to a stretching shaft 10 of the stretching device 8 . Preferably and in the exemplary embodiment, the unit consisting of the cooling device 3 and the stretching device 8 or the unit consisting of the cooling device 3, the intermediate channel 9 and the stretching shaft 10 is designed as a closed unit and, apart from the supply of cooling air in the cooling device 3, no further air supply takes place outside of this unit.

Expediently and in the exemplary embodiment, a diffuser 11 adjoins the stretching device 8 in the filament flow direction, through which the continuous filaments 2 are guided. After passing through the diffuser 11, the continuous filaments 2 are preferably and in the exemplary embodiment deposited on a depositing device designed as a depositing sieve belt 12. The deposit sieve belt 12 is expediently and in the exemplary embodiment designed as an endlessly circulating deposit sieve belt 12 . It is within the scope of the invention for the sieve belt 12 to be air-permeable, so that process air can be sucked off from below through the sieve belt 12 . For this purpose, and in the exemplary embodiment, a suction device 13 is arranged underneath the sieve belt 12 for placement.

the 2 shows a section through a continuous filament 2 with an eccentric core-sheath configuration. Such endless filaments 2 are preferably used for a spunbonded nonwoven layer with crimped endless filaments in the spunbonded nonwoven laminate according to the invention. It is a bicomponent filament with a first component based on polypropylene in the sheath 14 and with a second component based on polypropylene in the core 15. In the 2 it can be seen that in the case of the preferred continuous filaments 2 the sheath 14 of the filaments 2 in the filament cross-section preferably and in the exemplary embodiment has a constant thickness D over more than 50% of the filament circumference. Preferably and in the exemplary embodiment, the core 15 of the filaments 2—seen in the filament cross section—is designed in the shape of a segment of a circle. In the region of its constant thickness D, the jacket 14 preferably has a thickness D of 0.1 to 0.9 μm.

Claims (19)

Spunbonded nonwoven laminate with at least two spunbonded nonwoven layers, wherein at least one spunbonded nonwoven layer has crimped continuous filaments or consists or essentially consists of crimped continuous filaments, wherein the crimped continuous filaments are multicomponent filaments, in particular bicomponent filaments with a first component based on polypropylene and a second component based on polypropylene and where the specific density ϱ [g/cm ³ ] of the spunbonded nonwoven laminate is in Depending on the mass per unit area of the spunbonded nonwoven laminate lies below a limit density ϱ _G , which is defined by the following equation: $${\varrho }_G=9\frac{1}{cm}\times fl\ddot{a}cHenmasse\frac{G}{c{m}^2}+0.0393\frac{G}{c{m}^3}$$

spunbonded laminate claim 1 wherein the first component consists or essentially consists of a polypropylene blend or consists or essentially consists of a polypropylene copolymer. Spunbond laminate according to one of Claims 1 or 2 , wherein the second component consists or essentially consists of a polypropylene. Spunbond laminate according to one of Claims 1 until 3 wherein at least one spunbonded nonwoven layer of the laminate has crimped continuous filaments with a linear density of up to 2 denier, preferably with a linear density of less than 2 denier, preferably with a linear density of 1 to 1.7 denier and particularly preferably of 1.2 to 1.7 denier. Spunbond laminate according to one of Claims 1 until 4 wherein at least one spunbonded nonwoven layer comprises crimped continuous filaments having a core-sheath configuration, preferably an eccentric core-sheath configuration, and preferably wherein the first component is the sheath component and the second component is the core component. Spunbond laminate according to one of Claims 1 until 5 , wherein at least 25% of all filaments or continuous filaments of the laminate (fiber content) are crimped continuous filaments with a core-sheath configuration, in particular with an eccentric core-sheath configuration. Spunbond laminate according to one of Claims 5 or 6 , wherein in the case of the crimped continuous filaments with an eccentric core-sheath configuration, the sheath (14) of the filaments - seen in the filament cross section - over at least 20%, in particular over at least 25%, preferably over at least 30%, preferably over at least 35% and particularly preferably has a constant thickness D or a substantially constant thickness D over at least 40% of the filament circumference and the thickness of the jacket (14) in the area of its constant or substantially constant thickness D being expediently 0.1 to 4 µm, preferably 0. 1 to 3 µm, preferably 0.1 to 2 µm and very preferably 0.1 to 0.9 µm. Spunbond laminate according to one of Claims 1 until 7 , wherein the laminate has at least three spunbonded nonwoven layers, wherein at least one spunbonded nonwoven layer with crimped continuous filaments - in particular with crimped continuous filaments with an eccentric core-sheath configuration - is arranged on an outside of the laminate and wherein the linear density of the continuous filaments of this spunbonded nonwoven layer is preferably up to 2 denier, preferably less than 2 denier, more preferably 1 to 1.7 denier, and most preferably 1.2 to 1.7 denier. Spunbond laminate according to one of Claims 1 until 8th wherein at least one spunbonded nonwoven layer comprises crimped continuous filaments of side-by-side configuration. Spunbond laminate according to one of Claims 1 until 9 , wherein the laminate has a basis weight in the range from 10 to 40 g/m ² , in particular in the range from 12 to 35 g/m ² , preferably in the range from 13 to 30 g/m ² , preferably from 14 to 25 g/m ² and very preferably from 15 to 22 g/m ² . Spunbond laminate according to one of Claims 1 until 10 , wherein the first component comprises at least one polypropylene copolymer (CoPP), the polypropylene copolymer preferably having a proportion of the comonomer of 1 to 6% by weight, preferably 1.5 to 5% by weight. Spunbond laminate according to one of Claims 1 until 11 wherein the first and second components have different melt flow rates and wherein, for continuous filaments having a core-sheath configuration, preferably the second component forming the core component has a higher melt flow rate than the first component forming the sheath component. Spunbond laminate according to one of Claims 1 until 12 , wherein the ratio of the melt flow rate of the second component - in particular the core component - to the melt flow rate of the first component - in particular the sheath component - is 0.9 to 2.2, preferably 1 to 2. Spunbond laminate according to one of Claims 1 until 13 , wherein the ratio of the polydispersity index (PI) of the first component - in particular the sheath component - to the polydispersity index (PI) of the second component - in particular the core component - is 0.9 to 1.4, in particular 1 to 1.35. Spunbond laminate according to one of Claims 1 until 14 , wherein the melting temperature of the first component - in particular the shell component - is lower than the melting temperature of the second component - in particular the core component - and the melting temperature difference is expediently 0 to 20 °C, preferably 1 to 18 °C and preferably 2 to 16 °C . Spunbond laminate according to one of Claims 1 until 15 , wherein the second component or the second component used as the core component has at least one lubricant, preferably at least 1000 ppm (based on the entire filament) of at least one lubricant. Method for producing a spunbonded nonwoven laminate - in particular according to one of Claims 1 until 16 -, with at least two spunbonded nonwoven layers, wherein at least one spunbonded nonwoven layer is produced with crimped continuous filaments, wherein the crimped continuous filaments are multicomponent filaments, in particular bicomponent filaments with a first component based on polypropylene and a second component based on polypropylene, wherein at least one spunbonded nonwoven layer is connected by means of at least one hot roller and/or by means of at least one calender roller and/or with at least one hot-air oven, the spunbonded nonwoven laminate being finally consolidated by means of at least one calender roller and the laminate being produced with the proviso that the specific density ϱ [g/cm ³ ] of the spunbonded nonwoven laminate, depending on the mass per unit area of the spunbonded nonwoven laminate, is below a limit density ϱ _G that is defined by the following equation: $${\varrho }_G=9\frac{1}{cm}\times fl\ddot{a}cHenmasse\frac{G}{c{m}^2}+0.0393\frac{G}{c{m}^3}$$

procedure after Claim 17 , wherein the final consolidation is carried out with at least one calender roll, which has an “open dot” engraving. Nonwoven aggregate with at least one spunbonded nonwoven laminate according to one of Claims 1 until 16 and / or prepared by a method of claims 17 or 18 , where the laminate has a compression set (Compression Set) of at most 30%, in particular at most 20% and preferably at most 10% in the relaxed state due to compression - in particular in the course of further processing or further treatment - and where the specific density ϱ of the laminate is at most 30 %, in particular a maximum of 20% and preferably a maximum of 10% above the limit density ϱ _G .

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