Spunbond nonwoven laminate and method of making spunbond nonwoven laminate

Abstract

Spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer has crimped continuous filaments. The crimped continuous filaments are multicomponent filaments, in particular bicomponent filaments, having a first component based on polypropylene and a second component based on polypropylene. Depending on the mass per area of the spunbond nonwoven laminate, the specific density of the spunbond nonwoven laminate is below the limit density defined by the following equation

Description

TECHNICAL FIELD

[0001] The present invention relates to a spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer has crimped continuous filaments or consists essentially of crimped continuous filaments, wherein the crimped continuous filaments are multi-component filaments, in particular bi-component filaments. The present invention also relates to a method for producing a spunbond nonwoven laminate. Within the scope of the present invention, the continuous filaments relate to continuous filaments made of thermoplastic material. The continuous filaments differ from staple fibers by their almost continuous length, which has a much shorter length of for example 10 mm to 60 mm. BACKGROUND

[0002] Spunbond nonwoven laminates of the above-mentioned type and corresponding methods for producing such spunbond nonwoven laminates are known from the prior art and the practice of various embodiments. For many applications it is required to have nonwovens or nonwoven laminates with a large thickness and as small as possible unit area mass A large thickness is usually achieved by using crimped or corrugated filaments (creped filaments). Here, spiral or helical crimp is preferred. Multi-component filaments or bi-component filaments are used for producing crimped or creped filaments. In order to achieve crimping, it is sufficient if the two components of the bi-component filaments differ in the width of the molar mass distribution. Other differences (viscosity, melting point, usually different solidification processes) or combinations of differences also lead to crimping. The maximum crimping that can be achieved is usually only possible with specific formulations in slow single beam processes for producing individual spunbond nonwovens of various forms. In the case of multi-beam processes for the continuous production of multi-layer spunbond nonwovens, this crimping is usually too strong and leads to an undesirable uneven laydown or a laydown with an undesirable reduction in dimensional stability. So far, when seeking a compromise between high thickness and satisfactory filament laydown in multi-beam equipment, this is usually at the expense of the thickness. In the case of three-beam equipment, the corresponding threefold production speed is thus used for producing nonwoven laminates with a unit area mass of between 20 and 25 g / m 2 In the case of multi-beam equipment, the quality of the laydown can be improved by thinner filaments. However, the mixtures known from the prior art usually exhibit a reduction in nonwoven thickness for thinner filaments (greater cabin pressure in the cooling cabin, more stretching air during stretching, lower production throughput). The advantages of better laydown and producibility cannot be combined with high thickness here.

[0003] Fine fiber nonwovens are known from the applicant's European patent EP 3521495 B1. This fine fiber nonwoven has a good coverage and a high quality laydown and exhibits a soft, uniform surface. However, in the case of multiple beam applications, the thickness also becomes an issue.

[0004] Multicomponent filaments or bicomponent filaments with side-by-side configuration or eccentric core-sheath configuration are used in particular to achieve sufficient crimping and high thickness. Providing a high thickness is generally associated with a relatively high mass per area of the nonwoven material. This applies to single-layer nonwovens, but especially to multiple beam nonwovens produced in a multiple beam apparatus. The manufacture of multiple layers means that, on the one hand, each layer must be compacted or pre-consolidated to a greater extent so as not to damage the laydown of the layers during the passage of the subsequent beams, but also that the first layer is additionally further compacted when the next layer is laid down, and thus the thickness of the spunbond nonwoven laminate is significantly reduced compared to the good thickness that can be achieved in a single layer. Especially in the case of multiple beam apparatuses, for example three or more beams, there is thus a conflict of objectives in achieving a high thickness while at the same time a low mass per area, and solutions to this conflict of objectives have so far presented insurmountable problems for the person skilled in the art. So far, the target nonwoven thickness has generally resulted in a disproportionately high increase in the mass per area of the nonwoven layer or nonwoven laminate, or in a thick laminate with an uneven laydown. This also leads to an undesirably high material usage and thus to high costs.

[0005] It is therefore desirable to achieve a high thickness at as low a weight per area as possible. It must also be taken into account here that such a spunbond nonwoven laminate must meet the requirements in terms of softness, strength and in particular dimensional stability. Sufficient strength and in particular sufficient dimensional stability are required for further processing. In the laminates known from the prior art, the desired properties are achieved by reinforcing layers, for example non-crimped filament nonwoven layers or nonwoven layers with reduced crimped filaments, or by stable fine fiber nonwoven layers (for example with filaments of less than 1.5 denier) in combination with thicker nonwoven layers with ordinary denier (for example 1.7 to 2 denier) in the case of a thicker network and medium crimp, or with thicker nonwoven layers in the case of greater crimp. The desired properties are achieved in the laminates known from the prior art. However, the mass per area of the laminates is relatively high. SUMMARY

[0006] The present invention is based on the technical problem of providing a spunbond nonwoven laminate of the type mentioned at the outset, which has a higher thickness at essentially constant material usage compared to nonwovens known in practice or in the prior art, particularly in the case of production in a multi-beam device, and at the same time also has optimal softness, high strength and in particular high dimensional stability. The present invention is also based on the technical problem of providing a corresponding method for producing such a spunbond nonwoven laminate.

[0007] To solve this technical problem, the present invention teaches a spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer has crimped continuous filaments or consists of or essentially consists of crimped continuous filaments, wherein the crimped continuous filaments are multicomponent filaments, in particular bicomponent filaments, which have a first component based on polypropylene and a second component based on polypropylene, and wherein the specific density of the spunbond nonwoven laminate, depending on the areal mass of the spunbond nonwoven laminate is below the limit density defined by the equation

[0008]

[0009] the limit specific density is thereby linearly dependent on the areal mass of the spunbond nonwoven laminate.

[0010] The spunbond nonwoven laminate according to the present invention can consist of only two spunbond nonwoven layers, wherein at least one of these spunbond nonwoven layers has crimped continuous filaments. However, it is also within the scope of the present invention that the spunbond nonwoven laminate according to the present invention has more layers or nonwoven layers and for example comprises two or more spunbond nonwoven layers having crimped continuous filaments and / or two or more spunbond nonwoven layers having little or no crimped filaments. Important within the scope of the present invention is the presence of at least two spunbond nonwoven layers in the laminate, wherein at least one of the spunbond nonwoven layers has crimped continuous filaments.

[0011] The highly preferred embodiment of the present application is characterized in that the first component of the multicomponent filament or bicomponent filament consists of or essentially consists of a polypropylene mixture or consists of or essentially consists of a polypropylene copolymer (CoPP). The expression "essentially consists of" refers in particular to at least 90 wt.-%, preferably at least 95 wt.-%, preferably at least 98 wt.-% of the first component consisting of a polypropylene mixture or a polypropylene copolymer. The statement "essentially consists of" takes into account in particular the fact that additives or the like can also be contained in the first component in addition to the mentioned substances. These additives are in particular active substances such as pigments, plasticizers / lubricants, surface-active substances, nucleating agents or fillers such as chalk. The term "polypropylene mixture" refers in particular to a mixture of two or more homopolymers of polypropylene or a mixture of at least one homopolymer of polypropylene and at least one polypropylene copolymer or a mixture of two or more polypropylene copolymers. A polypropylene copolymer also refers in particular to the corresponding random copolymer.

[0012] Within the scope of the present application, the second component of the multicomponent filament or bicomponent filament consists of or essentially consists of polypropylene. The expression "essentially consists of" refers in particular to at least 90 wt.-%, preferably at least 95 wt.-%, preferably at least 98 wt.-% of the second component consisting of polypropylene. Within the scope of the present application, the second component consisting of or essentially consisting of polypropylene means that the second component consists of or essentially consists of a homopolymer of polypropylene or consists of or essentially consists of a polypropylene copolymer. In principle, the second component can also consist of or essentially consist of a polypropylene mixture, in which case the definition of the polypropylene mixture given in particular for the first component applies. Here, too, additives can be contained as for the first component, the kind and proportion of which can differ between the components.

[0013] A particularly preferred embodiment of the present application is characterized in that the at least one layer of a spun-bonded nonwoven fabric of continuous filaments with crimp has filaments with a fineness of at most 2 denier, preferably a fineness of less than 2 denier, preferably a fineness of less than 1.5 denier, particularly preferably 1 to 1.7 denier, most preferably 1.2 to 1.7 denier. In this respect, the present application is based on the insight that with finer filaments a solution to the technical problem is achieved by a sufficient crimping of the filaments, wherein these finer filaments are able to form a stable network of lay and thus obtain a dimensionally stable product.

[0014] A very preferred embodiment of the present application is characterized in that the crimped continuous filaments of the at least one spunbond nonwoven layer having crimped continuous filaments have a core-sheath configuration and particularly preferably have an eccentric core-sheath configuration. Here the first component of the multi- or bi-component filament advantageously forms the sheath component and the second component forms the core component. However, it is also within the scope of the present application that the at least one spunbond nonwoven layer having crimped continuous filaments has filaments with a side-by-side configuration. Here one side of the filament is formed by the first component and the other side is formed by the second component.

[0015] A highly recommended embodiment of the present application is characterized in that at least 25% of all filaments or continuous filaments of the laminate according to the present application are crimped continuous filaments having a core-sheath configuration, particularly having an eccentric core-sheath configuration. The above-mentioned proportion of filaments (fiber proportion) is suitably determined as follows: The spunbond nonwoven laminate is cut into lengths of at least 10 mm and a REM image of the cut surface is taken and evaluated. The fiber content of the filament type in question corresponds to the number of the respective filaments in the field of view based on all filaments in the cut surface in the field of view.

[0016] It is within the scope of the present application that in the case of crimped continuous filaments having an eccentric core-sheath configuration, the sheath of the filament (seen in the cross-section of the filament) has a constant thickness D or a substantially constant thickness D over at least 20%, particularly over at least 25%, preferably over at least 30%, preferably over at least 35%, particularly preferably over at least 40% of the circumference of the filament. The thickness of the sheath is suitably 0.1 to 4 μιη, preferably 0.1 to 3 μιη, preferably 0.1 to 2 μιη, very preferably 0.1 to 0.9 μιη in the region of its constant or substantially constant thickness D. The thickness D is recommended to be at least 100 nm and the thickness locally differs from the average thickness in the region of the constant or substantially constant thickness by a maximum of 400 nm, particularly a maximum of 300 nm, preferably a maximum of 200 nm.

[0017] A very preferred embodiment of the present application is characterized in that the laminate according to the present application has at least three spunbond nonwoven layers, wherein at least one spunbond nonwoven layer having crimped continuous filaments, particularly crimped continuous filaments having an eccentric core-sheath configuration, is arranged on the outside of the laminate and preferably the denier of the continuous filaments of this spunbond nonwoven layer is a maximum of 2 denier, preferably less than 2 denier, particularly preferably below 1.5 denier, particularly 1 to 1.7 denier and very preferably 1.2 to 1.7 denier.

[0018] A highly recommended embodiment of the present application is characterized in that the spunbond nonwoven laminate according to the present application has a basis weight of 10 to 40 g / m2, particularly 12 to 35 g / m2, very particularly 15 to 30 g / m2. 2 2 ​in the range of 13 to 30 g / m2 2 in the range of 14 to 25 g / m2 2 in the range of 15 to 22 g / m2 and very preferably 2 in the range of 13 to 30 g / m2

[0019] In the context of the present application, the first component of the multi- or bi-component filament is at least one polypropylene copolymer (CoPP) or has a polypropylene copolymer, wherein the first component preferably has a proportion of 1 to 7 wt.-%, preferably 1.5 to 5 wt.-%, of comonomer. It has been shown that the softness of the laminate according to the present application can be improved by this embodiment. The respective spunbond nonwoven layer having these crimped continuous filaments is preferably arranged on the outer side or surface of the spunbond nonwoven laminate according to the present application. Here, the crimped continuous filaments of the spunbond nonwoven layer on the surface of the laminate, preferably are crimped continuous filaments having a eccentric core-sheath configuration, and the sheath component of the above-mentioned crimped continuous filaments contains the above-mentioned polypropylene copolymer.

[0020] A particularly recommended embodiment of the present application is characterized in that the first and the second component of the multi- or bi-component filament have different melt flow rates (MFI), and in the case of continuous filaments having a core-sheath configuration, preferably the second component constituting the core component has a higher melt flow rate than the first component constituting the sheath component. In the context of the present application, 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 in the range of 0.9 to 2.5, preferably 1 to 2.2. In the context of the present application, the melt flow rate is preferably measured in g / 10 min according to ISO 1133 at 230 °C and 2.16 kg.

[0021] A particularly proven embodiment of the present application 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 in the range of 0.9 to 1.4, in particular 1 to 1.35. It is recommended that the first component (in particular the sheath component) has a broader molar mass distribution than the second component (in particular the core component). The polydispersity index here is the quotient of the weight-average molar mass M w and the number-average molar mass M n (PI = M w / M n ). The average molar mass is here in particular measured by gel permeation chromatography (GPC) and preferably according to the respective ISO 16014-1 :2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D 6474-12. The polydispersity index (PI = M w / Mn ) are usually used to measure sortenrein polymers. For simplicity it is thus assumed that the polydispersity index of a mixture polymer is composed of the polydispersity indices of the individual raw materials according to their proportion. The polydispersity index of a mixture polymer composed of polymers A and B is then calculated according to the following formula:

[0022] PI (mixture A+B) = A proportion x PI (A) + B proportion x PI (B).

[0023] A mixture polymer with 60% A and 40% B then has a polydispersity index PI (A+B) = 0.6 x PI (A) + 0.4 x PI (B).

[0024] According to a preferred embodiment of the present application, the melting temperature of the first component, in particular of the sheath component, is lower than the melting temperature of the second component, in particular of the core component, and advantageously the difference in melting temperature is from 0 to 20°C, preferably from 1 to 18°C and preferably from 2 to 16°C. The present application is based in this respect on the insight that in this embodiment, due to the lower melting temperature, the sheath component melts more easily than the core component, so that the effort in the thermal consolidation of the nonwoven layer and / or the nonwoven laminate is reduced. The melting temperature within the scope of the present application is measured according to ISO 11357-3 by DSC (Differential Scanning Calorimetry).

[0025] A preferred embodiment of the present application is characterized in that the second component or the second component used as core component has at least one lubricant and preferably at least 1000 ppm (based on the entire filament) of at least one lubricant. The present application is based on the insight that the softness of the spunbond nonwoven laminate can be improved in this way, in particular if the nonwoven layer in question is arranged on the surface or on the outside of the laminate. By mixing in the core component, the contamination of the spunbond nonwoven layer is reduced by the evaporated lubricant.

[0026] To solve the technical problem, the present application also teaches a method for producing a spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer is produced with crimped continuous filaments, wherein the crimped continuous filaments are multi-component filaments, in particular bi-component filaments, having a first component based on polypropylene and a second component based on polypropylene,

[0027] wherein at least one spunbond nonwoven layer is compacted or pre-consolidated by means of at least one heat roll and / or by means of at least one calender roll and / or with at least one hot-air oven, wherein the spunbond nonwoven laminate is finally consolidated by means of at least one calender roll

[0028] and wherein the production specification of the laminate is that the specific density of the spunbond nonwoven laminate depends on the mass per unit area of the spunbond nonwoven laminate below the limit density defined by the equation

[0029]

[0030] Within the scope of the present application, at least one layer of the spunbond nonwoven layer with crimped continuous filaments is compacted or pre-consolidated in the described manner. Further within the scope of the present application, at least two, preferably all of the spunbond nonwoven layers of the spunbond nonwoven laminate according to the present application are each compacted or pre-consolidated in the described manner.

[0031] A particularly preferred embodiment of the process according to the present application is characterized in that the final consolidation is carried out with at least one calender roll having an "open point" engraved pattern. The "open point" engraved pattern is characterized here by a embossing or pressing area of 8 to 15 %, in particular 10 to 14 % and preferably 11 to 13 %. The graphic density of the calender roll used for the final consolidation is recommended to be below 35 graphics / cm 2 , in particular below 30 graphics / cm 2 , preferably 18 to 28 graphics / cm 2 , preferably 20 to 28 graphics / cm 2 . The area of the graphics is advantageously 0.25 to 0.75 mm 2 , in particular 0.3 to 0.7 mm 2 , wherein compact graphics (circular, diamond or oval shapes with an aspect ratio below 2) are preferred. The center distance of two graphics of the calender roll is recommended to be between 0.9 and 2.5 mm, in particular between 1 and 2 mm. The engraved pattern depth of the calender roll is preferably 0.4 to 1.0 mm, in particular 0.5 to 0.9 mm.

[0032] Further within the scope of the present application, the coverage or opacity of the spunbond nonwoven laminate according to the present application is improved by the addition of pigments. For this purpose, the pigments are advantageously metered uniformly into all layers of the laminate. It is also within the scope of the present application to meter the pigments only into specific nonwoven layers. In this case, the metering of the pigments is advantageously carried out in nonwoven layers having a more uniform lay, so that the optical uniformity can be optimized for a given pigment share. In particular, the color can be introduced into nonwoven layers with less crimping of the filaments or into nonwoven layers without crimping of the filaments, or also into nonwoven layers with a higher mass per unit area. In principle, layers with finer filaments are also considered.

[0033] The specific density of the spunbond nonwoven laminate according to the present application below the limit density ​The definition relates to the manufacturing state of the spunbond nonwoven laminate according to the present application. However, the spunbond nonwoven laminate will typically undergo compression in the thickness direction acting on the spunbond nonwoven laminate in the processing chain between its production, further processing and packaging of the end product. Within the scope of the present application, the thickness of the laminate is only readjusted back up to a certain percentage again. This percentage of the original laminate thickness which the spunbond nonwoven laminate does not recover after the compression action has affected it is referred to as the compression set and represents a permanent deformation of the spunbond nonwoven laminate. Within the scope of the present application, the spunbond nonwoven laminate according to the present application has a maximum compression set of 30%, in particular 20%, preferably 10%, whereby the specific density of the spunbond nonwoven (especially when the end product is in use) is at most 30%, in particular at most 20%, preferably at most 10% above the limit density

[0034] The compression set of the laminate according to the present application is advantageously determined as follows: the spunbond nonwoven laminate has an original thickness D1, which is measured at a pressure of 0.5 kPa. The spunbond nonwoven laminate is then loaded or compressed at 6 kPa for three days and then left for three days without loading. Thereafter, the thickness D2 is measured. The compression set (DVR) is then calculated as follows: DVR = (D1 - D2) / D1. The measurement is repeated for at least five samples and the average value is then determined as the DVR.

[0035] The density of the spunbond nonwoven laminate according to the present application is preferably determined as follows: the proportion of air between the filaments of the laminate is ignored. The density is then derived from the quotient of the mass per unit area of the laminate / the thickness of the laminate. The mass per unit area is 50 g / m 2 and the thickness of the spunbond nonwoven is 0.2 mm, the density of the spunbond nonwoven is 50 / 0.2 = 0.25 g / cm 3 .

[0036] ​Within the scope of the present application, the spunbond nonwoven fabric used in the spunbond nonwoven laminate according to the application and in particular the at least one spunbond nonwoven fabric layer with crimped continuous filaments is also produced by the spunbond process. Below, a preferred spunbond process for the spunbond nonwoven fabric of the spunbond nonwoven laminate according to the application is described. The continuous filaments for the spunbond nonwoven fabric or for the spunbond nonwoven layer are spun by means of a spinneret or a spinneret head and are then cooled in a cooling device with a cooling chamber. It is also within the scope of the present application to provide a monomer suction device between the spinneret and the cooling device by means of which interfering gases occurring during the spinning process can be removed from the device. After passing through the cooling device, the filaments are advantageously guided through a stretching device for stretching the continuous filaments. It is recommended that the stretching device has an intermediate channel connecting the cooling device to the stretching shaft (Verstreckschacht) of the stretching device. According to one particularly preferred embodiment of the present application, 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 constructed as a closed unit and, in addition to the supply of cooling air into the cooling device, no further air is supplied to the unit from the outside.

[0037] The continuous filaments are guided through at least one diffuser, preferably in succession in the filament flow direction. After passing through the at least one diffuser, the continuous filaments are advantageously laid on a laying device, which is preferably constructed as a laying screen belt. The laying screen belt is recommended to be a circulating laying screen belt. The laying screen belt is advantageously constructed to be air-permeable, so that process air can be sucked through the laying screen belt from below. At least one suction device is advantageously provided for sucking process air below the laying screen belt.

[0038] The present application is based on the insight that in the spunbond nonwoven laminate according to the application a high thickness and a high softness can be achieved, while the laminate has a sufficiently high strength and dimensional stability. Furthermore, the filament lay is characterized by a satisfactory quality and sufficient uniformity. With the method according to the application, a higher thickness and a higher softness can be achieved with almost the same material usage compared to the methods known from the prior art, wherein the laminate is sufficiently strong and dimensionally stable. It should be emphasized that the advantages according to the application can be achieved by relatively simple measures and thus at relatively low costs. DETAILED DESCRIPTION

[0039] The plastics or polymers used in the following exemplary embodiments are specified in more detail in Table 1 below. Here, the polymers are labeled with the letters A to G 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 number average molar mass M n is given in the sixth column, and the weight average molar mass M w in the seventh column. The eighth column relates to the centrifuge average molar mass M z , the ninth column gives the polydispersity index PI = M w / M n . The quotient of the average molar masses M w / M z can be found in the last column. The polymers A to G are used in the following examples.

[0040] Table 1:

[0041]

[0042]

[0043] The following Tables 2 to 4 relate to two-component filaments suitable for the present application and having two components 1 and 2 based on polypropylene. Here the abbreviation PP means homopolypropylene, the abbreviation CoPP means polypropylene copolymer. If a different number (1, 2 or 3) is added, it indicates that they are different homopolypropylenes or different polypropylene copolymers. For example, PP1 and PP2 are two different homopolypropylenes. The homopolypropylenes and polypropylene copolymers are selected from the above Table 1.

[0044] For the assignment of the two components 1 and 2 of the two-component filaments in Tables 2 to 4 below, the following points should be noted: In the case of a combination of homopolypropylenes for components 1 and 2, the component with the narrower molecular weight distribution (or the smaller polydispersity index PI) is component 1. In the case of a combination of a homopolypropylene with a polypropylene copolymer (CoPP), the homopolypropylene is component 1 and the propylene copolymer is component 2. In the case of a combination of polypropylene copolymers (CoPP / CoPP), component 2 is the component with the broader molecular weight distribution (with the higher polydispersity index PI).

[0045] Bicomponent filaments with side-by-side configuration (S / S):

[0046] The bicomponent filaments of Table 2 with S / S configuration have a standard denier of 1.5 to 2.0 denier. The quotient of the melt flow rate of component 1 and the melt flow rate of component 2 is given in the third column for components 1 and 2. The quotient of the polydispersity index PI of component 2 and 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.

[0047] Table 2:

[0048]

[0049] Bicomponent filaments with eccentric core-sheath configuration (eC / S):

[0050] The following Table 3 lists the mixtures and parameters of bicomponent filaments with eC / S configuration and a standard denier of more than 1.5 denier according to the present application.

[0051] Table 3:

[0052]

[0053] The following Table 4 relates to bicomponent filaments according to the present application with eccentric core-sheath configuration and a fine denier of less than 1.5 denier.

[0054] Table 4:

[0055]

[0056] The raw materials and parameters or settings for producing the three-layer spunbond nonwoven laminate are given in the following Tables 5 and 6. Each laminate here was produced using a three-beam apparatus with beams 1, 2 and 3. Preferably, each beam corresponds to one of the apparatuses for producing spunbond-nonwoven shown in Table 1. Figure 1 The following Table 5 lists the raw materials and parameters or settings for producing the three-layer spunbond nonwoven laminate. The three-layer spunbond nonwoven laminate has a first, a second and a third spunbond nonwoven layer. The first and the third layer are produced using a three-beam apparatus with beams 1, 2 and 3. The second layer is produced using a two-beam apparatus with beams 1 and 2. The first and the third layer each have bicomponent filaments with components 1 and 2. The second layer has monocomponent filaments. In the second row of the following table, the raw material combination or polymer combination of each sample is given. Raw materials A to G are listed in Table 1. In the third row of the following table, the mass ratio of the two components of the sample to each other is given, respectively. The fourth row specifies the cabin pressure in the cooling chamber of the spunbond device used for each spunbond nonwoven layer, respectively. The last row gives the polymer throughput of the sample in the apparatus in kg / h / m. A spinneret with 6800 capillaries / m was used to produce the nonwoven layers or the respective filaments. The three-layer laminate was each finally consolidated using a calender roll with an "open point" engraved pattern.

[0057] Eight laminated samples of prior art three-layer spunbond nonwoven laminates are specified in Table 5. Each layer of the three-layer laminates samples 1 to 4 has crimped bicomponent filaments in a side-by-side configuration and has a denier of 1.2. In these samples 1 to 4, the polymer of each component of the bicomponent filaments is provided with 5% by weight of a spinning aid. As the spinning aid, Ziegler-Natta-homopolypropylene having a melt flow rate of 1200 g / 10 min and a melting temperature of 158°C is used here.

[0058] The laminated samples 5 to 8 have filaments with a denier of 1.7. Almost all layers have crimped bicomponent filaments in a side-by-side configuration. Only the second or middle layer of sample 5 has uncrimped monocomponent filaments, while the first layer of sample 8 has uncrimped bicomponent filaments in a core-sheath configuration.

[0059] Table 5:

[0060]

[0061]

[0062] The following Table 6 specifies four laminated samples (samples 9 to 12) of three-layer spunbond nonwoven laminates according to the application. Each layer of the three-layer spunbond nonwoven laminates has crimped bicomponent filaments in an eccentric core-sheath configuration. Only the middle or second layer of sample 12 has uncrimped monocomponent filaments. The filaments of samples 9 and 10 have a denier of 1.7, the filaments of sample 11 are 1.35 denier, and the filaments of sample 12 are 1.3 denier. The first given raw material forms the core component with respect to the raw materials given in the second row, respectively, and the mixture of raw materials given thereafter forms the sheath component of the bicomponent filaments. The mass ratio given in the third row relates to the mass ratio of core to sheath. The mass ratio given in the fourth row relates to the mass ratio of the constituents of the polymer mixture in the sheath component.

[0063] Table 6:

[0064]

[0065]

[0066] Table 7 below summarizes the basic parameters of the nonwoven laminate materials for all samples 1 to 12. As mentioned above, samples 1 to 8 are samples produced according to the prior art, and samples 9 to 12 are samples produced according to the teachings of the present invention. The weight per unit area of ​​the nonwoven laminate material is given in the second column, and the production line speed or production rate is given in the third column. The density of the nonwoven laminate material is given in g / cm3 in the fourth column. The filament fineness of the laminate material is listed in denier in the last column.

[0067] Table 7:

[0068] Samples weight (g / m 2 )]]> Linear speed (m / min) Density (g / cm 3 )]]> Linear speed (m / min) 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 8 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

[0069] Figure 3 Schematic diagrams of samples 1 to 12 are shown, where the density (g / cm³) of the entire spunbond nonwoven laminate material is displayed. 3 ) relative to the unit area mass (g / m²) of the entire laminate material 2 (Graphic drawing.) Samples 1 to 8, relating to the prior art, show measurement points above a line according to the invention, which represents the limiting density. The parameter values ​​of samples 9 to 12 according to the invention are below linear or below the limiting density. These spunbond nonwoven laminates are characterized by advantages according to the invention, which will be explained below.

[0070] Table 8 below shows the quotient of the melt flow rate of component 1 and component 2 of the first nonwoven layer of the nonwoven laminate material according to samples 1 to 12, and the quotient of the polydispersity index of component 2 and component 1.

[0071] Table 8:

[0072]

[0073] Table 9 below shows the quotient of melt flow rate of component 1 and component 2 of the three nonwoven layers of the nonwoven laminate material according to samples 1 to 12, and the quotient of polydispersity index of component 2 and component 1.

[0074] Table 9:

[0075]

[0076] In relation to Tables 8 and 9 Figure 4In the figure, the raw materials used to reflect the spunbond nonwoven laminate material or nonwoven layer are shown, illustrating the relationship between the quotient of the melt flow rate of component 1 and the melt flow rate of component 2 and the quotient of the polydispersity index of component 2 and the polydispersity index of component 1. In this figure, the parameter points in the frame region correspond to the bicomponent filaments (samples 9 to 12) according to the invention. Conversely, the parameter points on the left below the horizontal line correspond to the bicomponent filaments (samples 1 to 8) according to the prior art. In the prior art, starting from this point, i.e., for the MFR quotient above the horizontal line, the spinning stability gradually deteriorates. Further, for the first layer, starting from this point, i.e., the quotient of the polydispersity index on the right side of the vertically penetrating line (b), a thick nonwoven layer can be achieved through relatively strong crimping; however, the degree of crimping jeopardizes dimensional stability and thus also jeopardizes machine operability. For subsequent bundles 2 and 3, the region from Figure 4 Starting to the right of the vertical dashed line c), excessive curling may jeopardize the quality of the paving.

[0077] Conversely, in the frame region according to the invention, fine filaments with good crimp can be spun under good spinning stability, which enables the formation of spunbond nonwoven laminates with improved thickness and density according to the invention during layup. The invention is based on the understanding that region 1.1 is particularly superior to region 1.2 because fine filaments with good laminate density can be more easily obtained there (see also according to the invention). Figure 3 (Chart).

[0078] exist Figure 4 In direction 2 (marked in the middle), due to the excessively low viscosity (insufficient molecular weight of polypropylene), a gradual deterioration in spinning stability was observed, leading to a deterioration in the strength of the nonwoven laminate material. Based on... Figure 4 The spinning stability is lost in direction 3 marked in the chart due to a combination of an excessively wide molar mass distribution and an excessively large viscosity difference, making it impossible to obtain fine filaments or filaments with low fineness. Finally, according to... Figure 4 In the diagram, direction 4, marked as such, cannot produce fine filaments, although a higher density can be achieved due to the larger polydispersity index. The relatively strong crimp leads to uneven and sensitive filament layup. Filaments with excessive crimp are always at risk of being displaced in the layup area by horizontal air movement. This effect is particularly pronounced and uncontrollable here due to the relatively high fineness value. This contrasts with region 1.1 according to the invention, which has a smaller fineness value and a more stable filament layup network. Attached Figure Description

[0079] The invention will now be explained in more detail with reference to the accompanying drawings, which illustrate exemplary embodiments only. These drawings are shown in schematic form:

[0080] Figure 1A vertical section through the device for producing the spun-bond nonwoven layer of the spun-bond nonwoven laminate according to the application is shown,

[0081] Figure 2 A cross section through the preferred continuous filaments having an eccentric core-sheath configuration is shown, and

[0082] Figure 3 A diagram showing the relationship between density and mass per area is shown,

[0083] Figure 4 is a diagram showing the relationship between the melt flow rate ratio and the polydispersity index ratio.

[0084] Figure 1 A device for producing a spun-bond nonwoven layer for a spun-bond nonwoven laminate according to the application according to the spun-bond process is shown. At least one spun-bond nonwoven layer for a spun-bond nonwoven laminate having crimped continuous filaments is preferably also produced with this device or with this method. The device has a spinneret 1 for spinning continuous filaments 2 for a spun-bond nonwoven layer for a spun-bond nonwoven laminate according to the application. The continuous filaments 2 spun from the spinneret 1 are introduced into a cooling device 3 having a cooling chamber 4. Preferably and in the exemplary embodiment, air supply chambers 5, 6 arranged one above the other are arranged on opposite sides of the cooling chamber 4. Air of different temperatures is advantageously introduced into the cooling chamber 4 from the air supply chambers 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 produced during the spinning process can be removed from the device.

[0085] Recommended and in the exemplary embodiment, a stretching device 8 for stretching the continuous filaments 2 is connected downstream of the cooling device 3 in the direction of flow of the filaments. Advantageously and in the exemplary embodiment, the stretching device 8 has an intermediate channel 9 connecting the cooling device 3 to a stretching shaft 10 of the stretching device 8. Preferably and in the exemplary embodiment, the aggregate consisting of the cooling device 3 and the stretching device 8 or the aggregate consisting of the cooling device 3, the intermediate channel 9 and the stretching shaft 10 is configured as a closed aggregate and, in addition to the supply of cooling air in the cooling device 3, no further air is supplied to the device from the outside.

[0086] Advantageously and in exemplary embodiments, a diffuser 11 is connected to the stretching device 8 in the direction of flow of the filaments, through which the continuous filaments 2 are guided. After passing through the diffuser 11, the continuous filaments 2 are preferably and in exemplary embodiments laid on a laying device configured as a laying screen 12. The laying screen 12 is advantageously and in exemplary embodiments used as a circulating laying screen 12. Within the scope of the present application, the screen 12 is air-permeable, so that process air can be sucked through the screen 12 from below. For this purpose, advantageously and in exemplary embodiments, a suction device 13 is arranged below the screen 12.

[0087] Figure 2 A cross-section through a continuous filament 2 having an eccentric core-sheath configuration is shown. This continuous filament 2 is preferably used for a spun-bond nonwoven layer having crimped continuous filaments in the spun-bond nonwoven layer of the spun-bond nonwoven laminate according to the application. It is a bicomponent filament having a first component based on polypropylene in the sheath 14 and a second component based on polypropylene in the core 15. In the cross-section of the continuous filament 2, the sheath 14 has a constant thickness D of 0.1 to 0.9 pm, preferably and in exemplary embodiments over 50% of the circumference of the filament. Figure 2 Figure 2 It can be seen in the preferred continuous filament 2 that the sheath 14 of the filament 2 has a constant thickness D in the cross-section of the filament, preferably and in exemplary embodiments over 50% of the circumference of the filament. Preferably and in exemplary embodiments, the core 15 of the filament 2 (seen in the cross-section of the filament) is configured as a circular ring segment. In the region of its constant thickness D, the sheath 14 preferably has a thickness D of 0.1 to 0.9 pm.

Claims

1. A spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer comprises a core-sheath structure of crimped continuous filaments or is composed of core-sheath structured crimped continuous filaments, wherein the crimped continuous filaments are multi-component filaments having a first component based on polypropylene and a second component based on polypropylene, wherein the specific density of the spunbond nonwoven laminate depends on the unit area mass of the spunbond nonwoven laminate. Below the limiting density defined by the following equation :

2. The spunbond nonwoven laminate material according to claim 1, wherein the first component is composed of a polypropylene mixture or a polypropylene copolymer.

3. The spunbond nonwoven laminate material according to claim 1, wherein the second component is composed of polypropylene.

4. The spunbond nonwoven laminate according to claim 1, wherein at least one spunbond nonwoven layer of the laminate has crimped continuous filaments having a fineness of up to 2 denier.

5. The spunbond nonwoven laminate according to claim 4, wherein at least one spunbond nonwoven layer of the laminate has crimped continuous filaments having a fineness of 1 to 1.7 denier.

6. The spunbond nonwoven laminate according to claim 4, wherein at least one spunbond nonwoven layer of the laminate has crimped continuous filaments having a fineness of 1.2 to 1.7 denier.

7. The spunbond nonwoven laminate according to claim 1, wherein at least one spunbond nonwoven layer has crimped continuous filaments with an eccentric core-sheath structure.

8. The spunbond nonwoven laminate material according to claim 7, wherein the first component is a sheath component and the second component is a core component.

9. The spunbond nonwoven laminate of claim 1, wherein at least 25% of the fiber portion of all filaments or continuous filaments of the laminate is a crimped continuous filament having a core-sheath structure.

10. The spunbond nonwoven laminate material according to any one of claims 7 to 9, wherein, in the case of a crimped continuous filament having an eccentric core-sheath structure, the sheath of the filament seen in the filament cross-section has a constant thickness D for more than 20% of the filament circumference.

11. The spunbond nonwoven laminate of claim 10, wherein the sheath of the filament has a constant thickness D for more than 25% of the filament circumference.

12. The spunbond nonwoven laminate of claim 10, wherein the sheath of the filament has a constant thickness D for more than 30% of the filament circumference.

13. The spunbond nonwoven laminate of claim 10, wherein the sheath of the filament has a constant thickness D for more than 35% of the filament circumference.

14. The spunbond nonwoven laminate of claim 10, wherein the sheath of the filament has a constant thickness D for more than 40% of the filament circumference.

15. The spunbond nonwoven laminate according to claim 10, wherein the sheath thickness is 0.1 to 4 μm in the region of its constant thickness D.

16. The spunbond nonwoven laminate material according to claim 10, wherein the sheath thickness is 0.1 to 3 μm in the region of its constant thickness D.

17. The spunbond nonwoven laminate of claim 10, wherein the sheath thickness is 0.1 to 2 μm in the region of its constant thickness D.

18. The spunbond nonwoven laminate according to claim 10, wherein the sheath thickness is 0.1 to 0.9 μm in the region of its constant thickness D.

19. The spunbond nonwoven laminate according to claim 1, wherein the laminate has at least three spunbond nonwoven layers, wherein at least one spunbond nonwoven layer having crimped continuous filaments is disposed on the outer side of the laminate.

20. The spunbond nonwoven laminate according to claim 1, wherein at least one spunbond nonwoven layer has crimped continuous filaments arranged in parallel.

21. The spunbond nonwoven laminate material according to claim 1, wherein the laminate material has a content of 10 to 40 g / m³. 2 Mass per unit area within the specified range.

22. The spunbond nonwoven laminate material according to claim 1, wherein the laminate material has a content of 12 to 35 g / m³. 2 Mass per unit area within the specified range.

23. The spunbond nonwoven laminate material according to claim 1, wherein the laminate material has a content of 13 to 30 g / m³. 2 Mass per unit area within the specified range.

24. The spunbond nonwoven laminate material according to claim 1, wherein the laminate material has a content of 14 to 25 g / m³. 2 Mass per unit area within the specified range.

25. The spunbond nonwoven laminate material according to claim 1, wherein the laminate material has a content of 15 to 22 g / m³. 2 Mass per unit area within the specified range.

26. The spunbond nonwoven laminate material according to claim 1, wherein the first component comprises at least one polypropylene copolymer (CoPP).

27. The spunbond nonwoven laminate material according to claim 1, wherein the polypropylene copolymer has a comonomer content of 1-6% by weight.

28. The spunbond nonwoven laminate material according to claim 1, wherein the polypropylene copolymer has a comonomer content of 1.5-5% by weight.

29. The spunbond nonwoven laminate material according to claim 1, wherein the first component and the second component have different melt flow rates.

30. The spunbond nonwoven laminate material according to claim 1, wherein, in the case of continuous filaments having a core-sheath structure, the second component forming the core component has a higher melt flow rate than the first component forming the sheath component.

31. The spunbond nonwoven laminate material according to claim 1, wherein the ratio of the melt flow rate of the second component to the melt flow rate of the first component is 0.9 to 2.

2.

32. The spunbond nonwoven laminate material according to claim 1, wherein the ratio of the melt flow rate of the second component to the melt flow rate of the first component is 1 to 2.

33. The spunbond nonwoven laminate material according to claim 1, wherein the ratio of the polydispersity index PI of the first component to the polydispersity index PI of the second component is 0.9 to 1.

4.

34. The spunbond nonwoven laminate material according to claim 1, wherein the ratio of the polydispersity index PI of the first component to the polydispersity index PI of the second component is 1 to 1.

35.

35. The spunbond nonwoven laminate material according to claim 1, wherein the melting temperature of the first component is lower than the melting temperature of the second component, and wherein the melting temperature difference is 0 to 20°C.

36. The spunbond nonwoven laminate material according to claim 35, wherein the melting temperature difference is 1 to 18°C.

37. The spunbond nonwoven laminate material according to claim 35, wherein the melting temperature difference is 2 to 16°C.

38. The spunbond nonwoven laminate material according to claim 1, wherein the second component has at least one lubricant.

39. The spunbond nonwoven laminate material according to claim 38, wherein the second component has at least one lubricant at a concentration of at least 1000 ppm based on the entire filament.

40. A method for producing a spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer is prepared from a core-sheath structured crimped continuous filament, wherein the crimped continuous filament is a multi-component filament having a first component based on polypropylene and a second component based on polypropylene. At least one spunbond nonwoven fabric layer is compacted or pre-cured using at least one hot roller and / or at least one calendering roller and / or with at least one hot air oven, wherein the spunbond nonwoven fabric laminate is finally cured using at least one calendering roller. The production specifications of the laminated material are determined by the unit area mass and specific density of the spunbond nonwoven laminated material. Below the limiting density defined by the following equation :

41. The method as described in claim 40, characterized in that, The final curing is performed using at least one calendering roll with an "open point" engraved pattern.

42. A nonwoven aggregate material having at least one spunbond nonwoven laminate material according to any one of claims 1 to 39 and / or a nonwoven aggregate material having a spunbond nonwoven laminate material produced by the method according to claim 40 or 41, wherein the laminate material has a maximum compression set (DVR) of 30% due to compression in a relaxed state, and wherein the specific density of the laminate material is... At the limiting density The maximum is 30%.

43. The nonwoven aggregate material according to claim 42, wherein the laminate material has a maximum compression set (DVR) of 20% due to compression in a relaxed state.

44. The nonwoven aggregate material according to claim 42, wherein the laminate material has a maximum compression set (DVR) of 10% due to compression in a relaxed state.

45. The nonwoven aggregate material according to claim 42, wherein the specific density of the laminate material is... At the limiting density The maximum is 20%.

46. ​​The nonwoven aggregate material according to claim 42, wherein the specific density of the laminate material is... At the limiting density The maximum is 10%.

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