Spunbond nonwoven fabric laminate and method for manufacturing spunbond nonwoven fabric laminate

Abstract

The present invention provides a spunbond nonwoven fabric laminate that has a greater thickness than known nonwoven fabrics, while simultaneously possessing optimal flexibility, high strength, and especially high dimensional stability. [Solution] A spunbond nonwoven laminate comprising at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer comprises a shrunk endless filament. The shrunk endless filament is a multi-component filament having a first polypropylene-based component and a second polypropylene-based component, particularly a two-component filament. The specific density of the spunbond nonwoven laminate is ρ[g / cm³]. 3 The limiting density ρ is defined by the following equation, depending on the basis weight of the spunbond nonwoven laminate. G It is less than. TIFF2026108793000015.tif10170

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 contains or consists of or is essentially composed of crimped endless filaments, and the crimped endless filaments are multi-component filaments, particularly bi-component filaments. Furthermore, the present invention also relates to a method for producing a spunbond nonwoven laminate. It is within the framework of the present invention that the endless filaments are thermoplastic endless filaments. Endless filaments differ from staple fibers, which have considerably shorter lengths, for example, 10 mm to 60 mm, in terms of their substantially endless length. [Background technology]

[0002] The types of spunbond nonwoven laminates described above and corresponding methods for producing such spunbond nonwoven laminates are known in various embodiments in the prior art and practices. Many applications require nonwovens or nonwoven laminates with high thickness and as low a basis weight as possible. Generally, high thickness is achieved by using crimped or wavy filaments. In this case, spirally crimped filaments (spiral or helical crimps) are preferred. Multi-component or binary filaments are used to produce crimped or wavy filaments. To achieve crimp, it is sufficient that both components of the binary filament differ in terms of the width of their molar mass distribution. Other differences (viscosity, melting point, generally different solidification processes) or combinations thereof also result in crimp. In many cases, the maximum crimp achievable for a particular formulation is only available in all forms through low-speed single-beam methods for producing individual spunbond nonwovens. In multi-beam methods for continuously producing multiple spunbond nonwoven layers, such crimping is often too strong, leading to undesirable non-uniform deposits or deposits with undesirable reduced dimensional stability. Previously, in multi-beam systems, when a compromise was required between high thickness and satisfactory filament deposition, thickness was usually sacrificed. (Basis weight 20 g / m²) 2 and 25g / m 2 In a three-beam apparatus for producing a nonwoven laminate, and therefore, with a correspondingly three times higher production rate, it is not uncommon for the thickness of individual layers to be halved or two-thirds. In the case of a multi-beam apparatus, the quality of the deposit could be improved by using finer filaments. However, mixtures known from the prior art typically show a decrease in nonwoven thickness when using finer filaments (higher cabin pressure in the cooling cabin, more air for stretching during stretching, and lower processing volume). In other words, in this case, the advantages of good deposit and production rate cannot be combined with greater thickness.

[0003] Fine fiber nonwoven fabrics are known from the applicant's European Patent No. 3521495B1 (Patent Document 1). These fine fiber nonwoven fabrics exhibit good opacity and high-quality deposition, and are characterized by a flexible and homogeneous surface. However, even in this case, there is room for improvement in thickness when using multiple beams.

[0004] To produce sufficient crimp and high thickness, multi-component or bi-component filaments, particularly those with a side-by-side or eccentric core-sheath structure, are used. Providing high thickness generally involves a relatively high basis weight of the nonwoven fabric. This applies to single-layer nonwovens, but also to multi-beam nonwovens produced in multi-beam apparatuses. The production of multiple layers means that each layer must be relatively strongly compacted or pre-fixed so that the deposits of these layers are not damaged when passing through later beams. However, the first layer is further compacted when the next layer is placed on top, and therefore the thickness of the spunbond nonwoven laminate is also significantly reduced compared to the good thickness achievable in each individual layer. Thus, especially in multi-beam apparatuses, such as those with three or more beams, achieving high thickness simultaneously with a low basis weight presents a conflicting objective, and resolving such conflicting objectives has so far been an insurmountable problem for those skilled in the art. Previously, achieving the target nonwoven fabric thickness generally resulted in an unbalanced increase in the basis weight of the nonwoven layer or nonwoven laminate, or in the formation of thick laminates with uneven deposition. This also led to undesirable increases in material usage, and consequently, higher costs.

[0005] In other words, it is desirable to have a large thickness with the smallest possible basis weight. In this regard, it should also be considered that such spunbond nonwoven laminates must meet requirements regarding flexibility, strength, and especially dimensional stability. Sufficient strength, and especially sufficient dimensional stability, is necessary for secondary processing. Desired properties are achieved in laminates known from the prior art by a reinforcing layer, such as an un-crimped nonwoven layer or a nonwoven layer with a low degree of crimp, or by combining a relatively thick nonwoven layer using fibers of normal fineness (e.g., 1.7-2 denier) and a relatively high degree of crimp with a stable fine-fiber nonwoven layer with a denser network structure and a moderate degree of crimp (e.g., a nonwoven layer with filaments of 1.5 denier or less). However, in this case, the basis weight of the laminate is relatively large. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] European Patent No. 3521495B1 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention is based on the technical problem of providing a spunbond nonwoven laminate of the type described above that, in essentially, has a greater thickness than nonwovens known from Praktis or the prior art (especially in production using multi-beam equipment) and at the same time possesses optimal flexibility, high strength, and particularly high dimensional stability, given a certain amount of material usage. Furthermore, the present invention is also based on the technical problem of providing a suitable method for producing such a spunbond nonwoven laminate. [Means for solving the problem]

[0008] To solve this technical problem, the present invention provides a spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one of the spunbond nonwoven layers comprises or consists of or consists essentially of crimped endless filaments, wherein the crimped endless filaments are multicomponent filaments, particularly bicomponent filaments, having a first component based on polypropylene and a second component based on polypropylene, and the specific density ρ [g / cm 3 of the spunbond nonwoven laminate is less than a limiting density ρ G defined by the following equation, depending on the basis weight of the spunbond nonwoven laminate. The present invention teaches a spunbond nonwoven laminate.

[0009]

Number

[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 nonwovens comprises crimped endless filaments. However, it is within the scope of the present invention for the spunbond nonwoven laminate according to the present invention to comprise more layers or nonwoven layers, for example two or more spunbond nonwoven layers using crimped endless filaments and / or two or more spunbond nonwoven layers using uncrimped or low-crimp filaments. In the laminate, it is essential within the scope of the present invention that at least two spunbond nonwoven layers are present, wherein at least one of the spunbond nonwoven layers comprises crimped endless filaments.

[0011] One strongly recommended embodiment of the present invention is characterized in that the first component of a multi-component or two-component filament consists of or is essentially of a polypropylene mixture, or consists of or is essentially of a polypropylene copolymer (CoPP). The expression "essentially" means, in particular, that the first component consists of at least 90% by weight, especially at least 95% by weight, and preferably at least 98% by weight, of a polypropylene mixture or polypropylene copolymer. This expression "essentially" takes into account the situation in which, in addition to the substances described, additives may be further included in the first component. The additives are, in particular, active substances such as colorants, plasticizers / lubricants, surfactants, nucleating agents, or fillers such as chalk. The term "polypropylene mixture" means, in particular, a mixture of two or more homopolypropylenes, or a mixture of at least one homopolypropylene and at least one polypropylene copolymer, or a mixture of two or more polypropylene copolymers. Polypropylene copolymer also means, in particular, the corresponding random copolymer.

[0012] It is within the scope of this invention that the second component of a multi-component or two-component filament consists of or is essentially derived from polypropylene. The expression "essentially" means, in particular, that the second component consists of polypropylene in an amount of at least 90% by weight, especially at least 95% by weight, and preferably at least 98% by weight. Within the scope of this invention, "the second component consists of or is essentially derived from polypropylene" means, in particular, that the second component consists of or is essentially derived from homopolypropylene, or consists of or is essentially derived from polypropylene copolymer. In principle, the second component may also consist of or be essentially derived from a polypropylene mixture, in which case the definition of polypropylene mixture described for the first component applies in particular. In this case as well, additives as described for the first component may be included, in which case the type and proportion of additives may differ between the components.

[0013] One particularly preferred embodiment of the present invention is characterized in that at least one spunbond nonwoven layer using crimped endless filaments contains filaments having a fineness of up to 2 denier, particularly less than 2 denier, preferably less than 1.5 denier, particularly preferably 1 to 1.7 denier, and most preferably 1.2 to 1.7 denier. The present invention is based on the finding that the solution to the above technical problem is achieved by sufficient crimping of filaments using relatively thin filaments, where these relatively thin filaments enable a stable network structure of the deposit and thus a dimensionally stable product.

[0014] One very preferred embodiment of the present invention is characterized in that the crimped endless filaments of at least one spunbond nonwoven layer using crimped endless filaments have a core-sheath structure, particularly preferably an eccentric core-sheath structure. Advantageously, in this case, the first component of a multicomponent filament or a bicomponent filament forms the sheath component and the second component forms the core component. However, it is also within the scope of the present invention for the filaments in at least one spunbond nonwoven layer using crimped endless filaments to have a side-by-side structure. In this case, one side of the filament is formed by the first component and the other side is formed by the second component.

[0015] One highly recommended embodiment of the present invention is characterized in that at least 25% of all the filaments or endless filaments of the laminate according to the present invention are crimped endless filaments having a core-sheath structure, particularly an eccentric core-sheath structure. The above-mentioned proportion (fiber fraction) of the filaments is advantageously determined as follows: The spunbond nonwoven laminate is cut at a length of at least 10 mm, and SEM images are taken and evaluated from the cut surface. Here, the fiber fraction of the filament species in question corresponds to the number of corresponding filaments in the field of view based on all the filaments in the cut surface within the field of view.

[0016] In a crimped endless filament having an eccentric core-sheath structure, the sheath of the filament has a constant thickness D or an essentially constant thickness D over at least 20%, especially over at least 25%, particularly over at least 30%, preferably over at least 35%, particularly preferably over at least 40% of the filament perimeter length (seen in the filament cross-section), which is within the framework of the present invention. Advantageously, the sheath thickness in the range of a constant or essentially constant thickness D is 0.1 μm to 4 μm, especially 0.1 μm to 3 μm, preferably 0.1 μm to 2 μm, very preferably 0.1 μm to 0.9 μm. It is recommended that the thickness D is at least 100 nm and that the thickness differs from the average thickness in a constant thickness range or an essentially constant thickness range by up to 400 nm locally, especially by up to 300 nm, preferably by up to 200 nm.

[0017] One very preferred embodiment of the present invention is that the laminate according to the present invention comprises at least three spunbond nonwoven layers, wherein at least one spunbond nonwoven layer using a crimped endless filament, especially a crimped endless filament having an eccentric core-sheath structure, is arranged on the outside of the laminate, and the fineness of the endless filaments of this spunbond nonwoven layer is especially up to 2 dtex, preferably less than 2 dtex, particularly preferably less than 1.5 dtex, especially 1 to 1.7 dtex, very preferably 1.2 to 1.7 dtex.

[0018] One strongly recommended embodiment of the present invention is that the spunbond nonwoven laminate according to the present invention has a basis weight in the range of 10 to 40 g / m 2 and, in particular, in the range of 12 to 35 g / m 2 and, especially, in the range of 13 to 30 g / m 2 and preferably in the range of 14 to 25 g / m 2 and very preferably in the range of 15 to 22 g / m 2 and is characterized by having a basis weight within this range.

[0019] The first component of the multi-component or bi-component filament is at least one polypropylene copolymer (CoPP) or comprises a polypropylene copolymer, wherein the proportion of the comonomer of these first components is, in particular, 1 to 7% by weight, preferably 1.5 to 5% by weight, within the scope of the present invention. This embodiment has been shown to improve the flexibility of the laminate according to the present invention. In particular, the corresponding spunbond nonwoven fabric layer using this crimped endless filament is placed on the outside or surface of the spunbond nonwoven fabric laminate according to the present invention. In this case, the crimped endless filament of the spunbond nonwoven fabric layer on the surface of the laminate is, in particular, a crimped endless filament having an eccentric core-sheath structure, and the polypropylene copolymer is contained in the sheath component of the crimped endless filament.

[0020] One strongly recommended embodiment of the present invention is characterized in that the first and second components of a multi-component or bi-component filament have different melt flow rates (MFIs), and in an endless filament having a core-sheath structure, the second component forming the core component has a greater melt flow rate than the first component forming the sheath component. Within the framework of the present invention, the ratio of the second component (particularly the core component) to the melt flow rate of the first component (particularly the sheath component) is 0.9 to 2.5, and particularly 1 to 2.2. Within the framework of the present invention, the melt flow rate is measured in units of g / 10 mins under conditions of 230°C and 2.16 kg, in particular, according to ISO 1133.

[0021] One particularly demonstrated embodiment of the present invention is characterized in that the ratio of the polydispersity index (PI) of the first component (particularly the sheath component) to the polydispersity index (PI) of the second component (particularly the core component) is 0.9 to 1.4, particularly 1 to 1.35. It is recommended that the first component (particularly the sheath component) has a broader molar mass distribution than the second component (particularly the core component). In this case, the polydispersity index is the mass-average M of the molar mass. w and the number average of molar masses Mn The quotient is (PI=M w / M n ). In this case, the average molar mass is measured in particular by gel transmission chromatography (GPC), and more specifically according to ISO 16014-1:2003, ISO 16014-2:2003, ISO 16014-4:2003 and ASTM D6474-12. Polydispersity index (PI=M w / M n The polydispersity index is typically measured for a single polymer. Here, for simplicity, we assume that the polydispersity index of a polymer mixture is composed of the polydispersity indices of the individual raw materials according to their proportions. In this case, the polydispersity index of a polymer mixture consisting of polymers A and B is calculated according to the following formula: PI(mixture A + B) = proportion A × PI(A) + proportion B × PI(B) A polymer mixture containing 60% A and 40% B has a polydispersity index of PI(A+B) = 0.6 × PI(A) + 0.4 × PI(B).

[0022] According to one of the recommended embodiments of the present invention, the melting temperature of the first component (particularly the sheath component) is lower than that of the second component (particularly the core component), where the difference in melting temperatures is advantageously 0 to 20°C, particularly 1 to 18°C, and preferably 2 to 16°C. The present invention is based on the finding that, in this embodiment, the sheath component melts more easily at a lower melting temperature than the core component, thereby reducing the cost of thermally fixing the nonwoven layer and / or nonwoven laminate. Within the framework of the present invention, it is recommended that the melting temperature be measured by differential scanning calorimetry (DSC) in accordance with ISO 11357-3.

[0023] One preferred embodiment of the present invention is characterized in that the second component used as a second component or core component comprises at least one lubricant, and more particularly, at least one lubricant in a concentration of at least 1,000 ppm (relative to the total filaments). Herein, the present invention is based on the finding that by doing so, the flexibility of the spunbond nonwoven laminate can be improved, in particular when such a nonwoven layer is placed on the surface or outside of the laminate. By mixing it into the core component, contamination of the spunbond nonwoven layer by evaporating lubricants is reduced.

[0024] To solve the above technical problems, the present invention further provides a method for producing a spunbond nonwoven laminate having at least two spunbond nonwoven layers, comprising generating at least one spunbond nonwoven layer using a crimped endless filament, wherein the crimped endless filament is a multi-component filament, particularly a two-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-fixed using at least one hot roller and / or at least one calender roller and / or at least one hot air furnace, the spunbond nonwoven fabric laminate is final-fixed using at least one calender roller, and The laminate and the spunbond nonwoven fabric laminate have a specific density ρ[g / cm³]. 3 The limiting density ρ, which depends on the basis weight of the spunbond nonwoven laminate, is defined by the following equation. G The method described above is taught, which is manufactured under conditions less than [a certain value].

[0025]

number

[0026] One particularly preferred embodiment of the method according to the present invention is characterized in that the final fixation is carried out using at least one calendar roller having an "open dot" pattern. In this case, the "open dot" pattern is characterized by an embossed or pressurized surface of 8-15%, particularly 10-14%, preferably 11-13%. The pattern density of the calendar roller for final fixation is 1 cm 2 Fewer than 35 shapes per unit, especially 1 cm 2 The number of figures must be less than 30, especially within 1 cm. 2 18 to 28 figures per unit, preferably 1 cm 2 It is recommended that there be 20 to 28 shapes per piece. Ideally, the area of ​​each shape should be 0.25 to 0.75 mm². 2 Especially 0.3-0.7mm 2 In this case, compact shapes (circles, rhombuses, or ellipses with a length / width ratio of less than 2) are preferred. The distance between the midpoints of the two shapes on the calendar roller is recommended to be between 0.9 mm and 2.5 mm, particularly between 1 mm and 2 mm. In particular, the pattern depth of the calendar roller is 0.4 to 1.0 mm, especially 0.5 to 0.9 mm.

[0027] Furthermore, improving the opacity or concealment of the spunbond nonwoven laminate according to the present invention by adding a colorant is also within the scope of the present invention. To this end, the colorant is advantageously blended uniformly throughout all layers of the laminate. Alternatively, the colorant may be blended only in specific nonwoven layers. In this case, the colorant is advantageously blended in nonwoven layers having a more homogeneous deposit so that optical homogeneity can be optimized with respect to a given proportion of the colorant. The colorant can be introduced in particular into nonwoven layers with relatively low filament contraction, or into nonwoven layers where the filaments are not contracted, or into nonwoven layers with a relatively high basis weight. In principle, layers using relatively thin filaments are also possible.

[0028] critical density ρ G The definition of the specific density ρ of the spunbond nonwoven laminate according to this invention relates to the manufacturing state of the spunbond nonwoven laminate according to this invention. However, the spunbond nonwoven laminate will normally be subjected to thickness-direction compression acting on it during the process chain between its manufacture, secondary processing and packaging of the finished product. In this case, it is within the framework of this invention to adjust the thickness of the laminate so that it only returns to a certain percentage. This percentage of the thickness of the spunbond nonwoven laminate that does not recover compared to the original thickness of the laminate after the action of compression is called compression set and represents the permanent set of the spunbond nonwoven laminate. If the spunbond nonwoven laminate according to this invention has a maximum compression set of 30%, particularly 20%, and preferably 10%, then the specific density ρ of the spunbond nonwoven (particularly in the use state of the final product) is less than the limiting density ρ G It is within the scope of the present invention that the result may be up to 30%, particularly up to 20%, and preferably up to 10% larger than the given value.

[0029] Advantageously, the compression set of the laminate according to the present invention is determined as follows: The spunbond nonwoven laminate has an original thickness D1 measured at a pressure of 0.5 kPa. The spunbond nonwoven laminate is then loaded or compacted at 6 kPa for three days, and then stored without loading for three days. After this time, the thickness D2 is measured. At this time, the compression set (DVR) is calculated as follows: DVR = (D1 - D2) / D1. This measurement is repeated for at least five samples, and the average value is then taken as the DVR.

[0030] In particular, the density ρ of the spunbond nonwoven fabric laminate according to the present invention is determined as follows: the proportion of air between the filaments of the laminate is ignored. In this case, the density is obtained from the quotient of the basis weight of the laminate / the thickness of the laminate. That is, 50 g / m 2 The density of a spunbond nonwoven fabric with a basis weight of 50 / 0.2 mm and a thickness of 0.2 mm is 50 / 0.2 = 0.25 g / cm³. 3 That is the case.

[0031] It is within the scope of the present invention that the spunbond nonwoven fabric used in the spunbond nonwoven laminate according to the present invention, and in particular the at least one spunbond nonwoven layer using a spunbond endless filament, are also manufactured by a spunbond method. A preferred spunbond method for the spunbond nonwoven fabric in the spunbond nonwoven laminate according to the present invention is described below. The endless filament for the spunbond nonwoven fabric or spunbond nonwoven layer is spun using a spinning nozzle or spinneret and then cooled in a cooling device having a cooling chamber. It is within the scope of the present invention that a monomer suction device is placed between the spinning nozzle and the cooling device, and therefor, undesirable gases generated during the spinning process can be removed from the device. After passing through the cooling device, the filament is advantageously guided to a stretching device for stretching the endless filament. It is recommended that the stretching device have an intermediate channel, which connects the cooling device and the stretching shaft of the stretching device. According to a particularly preferred embodiment of the present invention, a coupling machine comprising a cooling device and a stretching device, or a coupling machine comprising a cooling device, an intermediate channel and a stretching shaft, is configured as a closed coupling machine, and no further air is supplied to this coupling machine from the outside, other than the supply of cooling air into the cooling device.

[0032] Preferably, in the direction of filament flow, the stretcher is connected to at least one diffuser through which the endless filament is guided. Advantageously, after passing through at least one diffuser, the endless filament is deposited on a deposition unit, which is configured in particular as a deposition screen belt. The deposition screen belt is preferably an endlessly circulating deposition screen belt. Advantageously, the deposition screen belt is designed to be air permeable, so as to allow the suction of process air from below through the deposition screen belt. Advantageously, at least one suction device is provided for the suction of process air below the deposition screen belt.

[0033] The present invention is based on the finding that, in a spunbond nonwoven fabric laminate according to the present invention, it is possible to achieve large thickness and high flexibility while maintaining sufficiently high strength and dimensional stability of the laminate. In addition, the filament deposition is characterized by satisfactory quality and sufficient homogeneity. By using the method according to the present invention, greater thickness and higher flexibility can be achieved with almost the same amount of material usage compared to methods known from the prior art, while the laminate remains sufficiently robust and dimensionally stable. The advantages of the present invention should be emphasized as being achievable by relatively simple means and therefore at relatively low cost. [Examples]

[0034] The plastics or polymers used in the following examples are identified in detail in Table 1 below. Here, each polymer is indicated by the letters A to G used in the examples. In addition to the manufacturer's name and polymer type, the fourth column shows the polymer's melt flow rate (MFR) in g / 10 min, and the fifth column shows the melting point (TM) in °C. The sixth column shows the number average molar mass (M). n This shows the mass-average M of the molar mass in the seventh column. w This shows the centrifugal average M of the molar mass. The eighth column shows the centrifugal average M of the molar mass. z Regarding this, and the ninth column is the polydispersity index PI=M w / M n The following is described: The quotient M of the average molar mass. w / M z It is listed in the last column. Polymers A to G are used in the following examples.

[0035] [Table 1]

[0036] Tables 2-4 below relate to two-component filaments suitable for the present invention, having two polypropylene-based components 1 and 2. Here, the abbreviation PP means homopolypropylene, and the abbreviation CoPP means polypropylene copolymer. If a different number (1, 2, or 3) is added, it indicates that it is a different homopolypropylene or a different polypropylene copolymer. That is, PP1 and PP2 are, for example, two different homopolypropylenes. In this case, the homopolypropylene and polypropylene copolymer were selected from Table 1 above.

[0037] Regarding the assignment of components 1 and 2 in the two-component filaments in Tables 2-4 below, the following points should be noted: When homopolypropylene is combined for components 1 and 2, the component with the narrower molecular weight distribution (or a smaller polydispersity index PI) is component 1. When homopolypropylene is combined with polypropylene copolymer (CoPP), homopolypropylene is component 1 and propylene copolymer is component 2. In the case of polypropylene copolymer combinations (CoPP / CoPP), component 2 is the component with a broader molecular weight distribution (a larger polydispersity index PI).

[0038] Two-component filaments with a side-by-side (S / S) structure: The two-component filaments in Table 2, having an S / S structure, have a standard fineness of 1.5 to 2.0 denier. Here, for components 1 and 2, the third column shows the quotient of the melt flow rate of component 1 divided by the melt flow rate of component 2. The fourth column shows the quotient of the polydispersity index PI of component 2 to that of component 1. The fifth column shows the absolute difference between the melting temperature of component 1 and the melting temperature of component 2.

[0039] [Table 2]

[0040] Two-component filament with eccentric core-sheath structure (eC / S). Table 3 below lists the mixtures and parameters for the two-component filament according to the present invention having an eC / S structure with a standard fineness greater than 1.5 denier.

[0041] [Table 3]

[0042] Table 4 below relates to a two-component filament according to the present invention having an eccentric core-sheath structure with a fine fiber density of less than 1.5 denier.

[0043] [Table 4]

[0044] Tables 5 and 6 below show the raw materials and parameters or settings for the production of three-layer spunbond nonwoven laminates. Each laminate is produced using a three-beam apparatus equipped with beams 1, 2, and 3. In particular, each beam corresponds to the apparatus shown in Figure 1 for the production of spunbond nonwovens. Almost all nonwoven layers of these three-layer spunbond nonwoven laminates contain crimped two-component filaments having components 1 and 2. Only the middle or second nonwoven layer of samples 5 and 12 contains single-component filaments. The second row of the following tables shows the raw material combination or polymer combination for each sample. Raw materials A to G are those listed in Table 1. The third row of the following tables shows the mass ratio between the two components for each sample. The fourth row identifies the cabin pressure in the cooling chamber of the spunbond nonwoven apparatus used for each spunbond nonwoven layer. The last row shows the polymer processing rate in kg / g / m for each sample. To generate the nonwoven fabric layer or the corresponding filament, spinning nozzles with 6,800 tubulars per meter were used. The three-layer laminates were then fixed using a calendar roller with an "open dot" pattern.

[0045] Table 5 identifies eight laminate samples of three-layer spunbond nonwoven fabric laminates following the prior art. Each layer of three-layer laminate samples 1-4 contains crimped two-component filaments with a side-by-side structure and a fineness of 1.2 denier. In these samples 1-4, 5% by weight of a spinning aid was added to the polymer of each component of the two-component filament. The spinning aid used was Ziegler-Natta homopolypropylene with a melt flow rate of 1,200 g / 10 min and a melting temperature of 158°C.

[0046] Laminate samples 5-8 contain filaments with a fineness of 1.7 denier. Almost all layers contain crimped two-component filaments with a side-by-side structure. Only the second or middle layer of sample 5 contains uncrimped single-component filaments, and only the first layer of sample 8 contains uncrimped core-sheathed two-component filaments.

[0047] [Table 5]

[0048] Table 6 below identifies four laminate samples (Samples 9 to 12) of the three-layer spunbond nonwoven laminate according to the present invention. Each layer of these three-layer spunbond nonwoven laminates contains crimped two-component filaments in an eccentric core-sheath structure. Only the middle or second layer of Sample 12 contains uncrimped single-component filaments. The filaments of Samples 9 and 10 have a fineness of 1.7 denier, the filament of Sample 11 has a fineness of 1.35 denier, and the filament of Sample 12 has a fineness of 1.3 denier. In the raw materials listed in the second row, the first raw material listed forms the core component of the two-component filament, and the subsequent raw material mixture forms the sheath component. The mass ratios listed in the third row relate to the core:sheath mass ratio. The mass ratios listed in the fourth row relate to the mass ratio of the components of the polymer mixture in the sheath component.

[0049] [Table 6]

[0050] Table 7 below summarizes the essential parameters of all nonwoven laminates from Samples 1 to 12. As previously mentioned, Samples 1 to 8 were manufactured according to the prior art, while Samples 9 to 12 were manufactured according to the teachings of the present invention. The second column shows the basis weight of the nonwoven laminate, and the third column shows the linear velocity or production rate. The fourth column shows the density of the nonwoven laminate in g / cm³. 3 This is shown. The last column lists the filament thickness of the laminate in denier.

[0051] [Table 7]

[0052] Figure 3 shows graphs for samples 1-12, illustrating the overall density (g / cm³) of the spunbond nonwoven laminate. 3 ) is the basis weight (g / m²) of the entire laminate. 2 ) is plotted against the limiting density ρ. Samples 1-8 relating to the prior art have a limiting density ρ G The measurement points are shown on the straight line according to the present invention, which represents the parameter values ​​of samples 9-12 according to the present invention, which are below the straight line or below the limiting density. These spunbond nonwoven laminates feature the advantages of the present invention, which are further described below.

[0053] Table 8 below shows the quotient of the melt flow rate of component 1 relative to component 2, and the quotient of the polydispersity index of component 2 relative to component 1, for the first nonwoven layer of the nonwoven laminates of samples 1 to 12.

[0054] [Table 8]

[0055] Table 9 below shows the quotient of the melt flow rate of component 1 relative to component 2, and the quotient of the polydispersity index of component 2 relative to component 1, for the three nonwoven layers of the nonwoven laminates of samples 1 to 12.

[0056] [Table 9]

[0057] In Figure 4, which relates to Tables 8 and 9, 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 for the raw materials of the spunbond nonwoven laminate or nonwoven layer. In this graph, the parameter points within the framed area correspond to the two-component filaments according to the present invention (samples 9-12). In contrast, the parameter points to the lower left of the horizontal line correspond to the two-component filaments according to the prior art (samples 1-8). In the prior art, it is assumed that spinning stability deteriorates further for MFR quotients above the parallel lines. Furthermore, for the first layer, in the case of the polydispersity index quotient to the right of the vertical solid line b), a thick nonwoven layer can be achieved by relatively strong crimping, but it is assumed that the degree of crimping may impair dimensional stability and therefore mechanical runability. For the subsequent beams 2 and 3, the region where excessive crimping may impair deposition stability begins to the right of the vertical dashed line c) in Figure 4.

[0058] In contrast, in the region enclosed by the frame according to the present invention, fine filaments with good crimp can be spun with good spinning stability, which makes it possible to deposit spunbond nonwoven fabrics with improved thickness and density according to the present invention. The present invention is based on the finding that region 1.1 is particularly preferable to region 1.2 because finer filaments can be obtained more easily with good density in the laminate (see also the graph in Figure 3).

[0059] In direction 2 shown in the graph of Figure 4, a gradual deterioration of spinning stability due to excessively low viscosity (excessively low molecular weight of polypropylene), and therefore a deterioration in the strength of the nonwoven laminate, is observed. In direction 3 shown in the graph of Figure 4, spinning stability is lost due to a combination of an excessively broad molar mass distribution and an excessively large viscosity difference, and therefore, fine filaments or filaments with low fineness are not possible. Finally, in direction 4 shown in the graph of Figure 4, although a higher density can be obtained due to a relatively large quotient of the polydispersity index, fine filaments cannot be spun. Relatively strong crimping results in heterogeneous and weak filament deposits. With excessively strong crimping, there is always a risk of displacement due to horizontal air movement in the deposit area. Here, with relatively high fineness values, this effect is particularly pronounced and uncontrollable. This is in contrast to region 1.1 according to the present invention, which has smaller fineness values ​​and a more stable reticular structure of filament deposits.

[0060] The present invention will be described in more detail below, based on drawings showing only one embodiment. [Brief explanation of the drawing]

[0061] [Figure 1] This shows a vertical cross-sectional view of an apparatus for manufacturing a spunbond nonwoven fabric layer of a spunbond nonwoven fabric laminate according to the present invention. [Figure 2] This is a cross-sectional view of a preferred endless filament having an eccentric core-sheath structure. [Figure 3] This is a graph showing density as a percentage of basis weight. [Figure 4] This is a graph of the quotient of the meltflow rate against the quotient of the polydispersity index.

[0062] Figure 1 shows an apparatus for producing a spunbond nonwoven layer for a spunbond nonwoven laminate of the present invention by the spunbond method. By using this apparatus or method, in particular, at least one spunbond nonwoven layer using crimped endless filaments for the spunbond nonwoven laminate is produced. The apparatus comprises a spinneret 1 for spinning endless filaments 2 for the spunbond nonwoven layer of the spunbond nonwoven laminate of the present invention. The endless filaments 2 spun from the spinneret 1 are introduced into a cooling device 3 having a cooling chamber 4. In particular and in this embodiment, air supply cabins 5 and 6 are arranged vertically on two opposing sides of the cooling chamber 4. From these vertically arranged air supply cabins 5 and 6, air at different temperatures is advantageously introduced into the cooling chamber 4. Preferably and in this embodiment, a monomer suction device 7 is arranged between the spinneret 1 and the cooling device 3. This monomer suction device 7 can be used to remove interfering gases generated during the spin process from the apparatus.

[0063] In the recommended and embodiment, a stretcher 8 for stretching the endless filament 2 is connected after the cooling device 3 in the filament flow direction. Advantageously and in the embodiment, the stretcher 8 includes an intermediate channel 9 which connects the cooling device 3 to the stretcher shaft 10 of the stretcher 8. Preferably and in the embodiment, the coupling machine consisting of the cooling device 3 and the stretcher 8, or the coupling machine consisting of the cooling device 3, the intermediate channel 9 and the stretcher shaft 10, is configured as a closed coupling machine, and no further external air is supplied to this coupling machine other than the supply of cooling air into the cooling device 3.

[0064] Advantageously, and in this embodiment, in the direction of filament flow, a diffuser 11 is connected to the stretching device 8, through which the endless filament 2 is guided. After passing through the diffuser 11, the endless filament 2 is deposited on a deposit device, which in particular, and in this embodiment, is configured as a deposit screen belt 12. Advantageously, and in this embodiment, the deposit screen belt 12 is configured as an endlessly circulating deposit screen belt 12. It is within the scope of the present invention that the deposit screen belt 12 is air permeable, and thus process air can be drawn in from below through the deposit screen belt 12. For this purpose, advantageously, and in this embodiment, a suction device 13 is located below the deposit screen belt 12.

[0065] Figure 2 shows a cross-section of an endless filament 2 having an eccentric core-sheath structure. Such an endless filament 2 is preferably used in a spunbond nonwoven layer using a crimped endless filament in a spunbond nonwoven laminate according to the present invention. This is a two-component filament comprising a first polypropylene-based component in the sheath 14 and a second polypropylene-based component in the core 15. From Figure 2, in the preferred endless filament 2 of the sheath 14, the filament 2 has a constant thickness D over more than 50% of the filament circumference in its filament cross-section, particularly in this embodiment. Preferably in this embodiment, the core 15 of the filament 2 is formed in an arc shape when viewed in the filament cross-section. The sheath 14 has a thickness D of 0.1 to 0.9 μm in its constant thickness D region, particularly.

Claims

1. A spunbond nonwoven laminate having at least two spunbond nonwoven layers, wherein at least one spunbond nonwoven layer contains or consists of crimped endless filaments, and the crimped endless filaments are a multi-component filament, particularly a two-component filament, using a first polypropylene-based component and a second polypropylene-based component, and the specific density of the spunbond nonwoven laminate is ρ [g / cm³]. ３ The critical density ρ, which depends on the basis weight of the spunbond nonwoven laminate, is defined by the following equation. Ｇ A spunbond nonwoven laminate that is less than [amount missing]. [Math 1]

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

3. The spunbond nonwoven laminate according to claim 1 or 2, wherein the second component consists of or is essentially made of polypropylene.

4. A spunbond nonwoven laminate according to any one of claims 1 to 3, wherein at least one spunbond nonwoven layer of the laminate comprises crimped endless filaments having a fineness up to 2 denier, particularly less than 2 denier, preferably 1 to 1.7 denier, and especially preferably 1.2 to 1.7 denier.

5. A spunbond nonwoven laminate according to any one of claims 1 to 4, wherein at least one spunbond nonwoven layer comprises crimped endless filaments having a core-sheath structure, preferably an eccentric core-sheath structure, and in particular, the first component is a sheath component and the second component is a core component.

6. A spunbond nonwoven fabric laminate according to any one of claims 1 to 5, wherein at least 25% (fiber fraction) of the total filaments or endless filaments of the laminate are crimped endless filaments having a core-sheath structure, particularly an eccentric core-sheath structure.

7. A crimped endless filament having an eccentric core-sheath structure, wherein the sheath of the filament has a constant thickness D or essentially constant thickness D over at least 20%, particularly at least 25%, especially at least 30%, preferably at least 35%, and especially preferably at least 40% of the filament circumference when viewed in cross-section of the filament, and advantageously, the thickness of the sheath is 0.1 to 4 μm, particularly 0.1 to 3 μm, preferably 0.1 to 2 μm, and very preferably 0.1 to 0.9 μm, in the range of its constant or essentially constant thickness D.

8. A spunbond nonwoven fabric laminate according to any one of claims 1 to 7, wherein the laminate comprises at least three spunbond nonwoven fabric layers, wherein at least one spunbond nonwoven fabric layer using crimped endless filaments, particularly crimped endless filaments having an eccentric core-sheath structure, is disposed on the outside of the laminate, and in particular the fineness of the endless filaments of the spunbond nonwoven fabric layer is up to 2 denier, preferably less than 2 denier, particularly 1 to 1.7 denier, and very preferably 1.2 to 1.7 denier.

9. A spunbond nonwoven laminate according to any one of claims 1 to 8, wherein at least one spunbond nonwoven layer comprises crimped endless filaments having a side-by-side structure.

10. 10-40 g / m ２ The range, especially 12-35 g / m ２ The range, particularly 13-30 g / m ２ In the range of 14 to 25 g / m², preferably 14 to 25 g / m². ２ In the range of 15 to 22 g / m², very preferably 15 to 22 g / m² ２ A spunbond nonwoven fabric laminate according to any one of claims 1 to 9, having a basis weight in the range of [specified range].

11. A spunbond nonwoven fabric laminate according to any one of claims 1 to 10, wherein the first component comprises at least one polypropylene copolymer (CoPP), and in this case, the polypropylene copolymer has a proportion of 1 to 6% by weight, preferably 1.5 to 5% by weight, of comonomers.

12. An endless filament having a core-sheath structure, wherein the first and second components have different melt flow rates, and in particular, the second component forming the core component has a larger melt flow rate than the first component forming the sheath component, according to any one of claims 1 to 11.

13. A spunbond nonwoven laminate according to any one of claims 1 to 12, wherein the ratio of the melt flow rate of the second component, particularly the core component, to the melt flow rate of the first component, particularly the sheath component, is 0.9 to 2.2, and particularly 1 to 2.

14. A spunbond nonwoven laminate according to any one of claims 1 to 13, wherein the ratio of the polydispersity index (PI) of the first component, particularly the sheath component, to the polydispersity index (PI) of the second component, particularly the core component, is 0.9 to 1.4, particularly 1 to 1.

35.

15. A spunbond nonwoven laminate according to any one of claims 1 to 14, wherein the melting temperature of the first component, particularly the sheath component, is lower than that of the second component, particularly the core component, and the difference in melting temperatures is advantageously 0 to 20°C, particularly 1 to 18°C, and preferably 2 to 16°C.

16. A spunbond nonwoven laminate according to any one of claims 1 to 15, wherein the second component used as a second component or core component comprises at least one lubricant, and more particularly, comprises at least one lubricant in a proportion of at least 1000 ppm (relative to the total filaments).

17. A method for producing a spunbond nonwoven fabric laminate having at least two spunbond nonwoven fabric layers, particularly the spunbond nonwoven fabric laminate according to any one of claims 1 to 16, comprising: generating at least one spunbond nonwoven fabric layer using a crimped endless filament, wherein the crimped endless filament is a multi-component filament, particularly a two-component filament, using a first component based on polypropylene and a second component based on polypropylene. At least one spunbond nonwoven fabric layer is compacted or pre-fixed using at least one hot roller and / or at least one calender roller and / or at least one hot air furnace. The spunbond nonwoven fabric laminate is finalized using at least one calender roller, and and the laminate has a basis weight ρ [g / cm ３ that depends on the basis weight of the spunbond nonwoven laminate and is defined by the following equation as the limiting density ρ Ｇ less than and is manufactured under the condition that The aforementioned method. [Math 2]

18. The method according to claim 17, wherein the final fixation is performed using at least one calendar roller having an "open dot" pattern.

19. A nonwoven fabric assembly comprising at least one spunbond nonwoven fabric laminate manufactured according to any one of claims 1 to 16 and / or the method of claim 17 or 18, wherein the laminate has a compression set (DVR) of up to 30%, particularly up to 20%, preferably up to 10% in a relaxed state, due to compression, particularly compression in the process of secondary processing or secondary treatment, and the specific density ρ of the laminate is equal to the critical density ρ Ｇ The nonwoven fabric aggregate is up to 30%, particularly up to 20%, and preferably up to 10%, larger than the above.

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