Spunbonded nonwoven with crimped fine fibers

Abstract

The invention relates to a spunbonded nonwoven having crimped multicomponent fibers, wherein a first component of the multicomponent fibers consists of a first thermoplastic polymer material comprising a first thermoplastic base polymer and a second component of the multicomponent fibers consists of a second thermoplastic polymer material comprising a second thermoplastic base polymer that is different from the first base polymer. The at least one of the first polymer material or the second polymer material is a polymer blend that comprises, further to the respective base polymer, between 1 and 10 weight percent of a high melt flow rate polymer that has a melt flow rate of between 600 and 3,000 g/10 min. The fibers have a linear mass density of less than 1.5 denier. The average crimp number of the crimped multicomponent fibers is in the range of at least 5 and preferably at least 8 crimps per cm in the fiber. The invention further relates to a method for making such spunbonded nonwoven, a multilayer fabric wherein at least one layer comprises such spunbonded nonwoven and a hygiene product comprising such spunbonded nonwoven or multilayer fabric.

Claims

1. A spunbonded nonwoven having crimped multicomponent fibers, wherein a first component of the multicomponent fibers consists of a first thermoplastic polymer material comprising a first thermoplastic base polymer and a second component of the multicomponent fibers consists of a second thermoplastic polymer material comprising a second thermoplastic base polymer that is different from the first thermoplastic base polymer, wherein the first thermoplastic base polymer and the second thermoplastic base polymer have a melt flow rate of between 15 and 60 g/10 min as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg, wherein the first thermoplastic polymer material and the second thermoplastic polymer material are each a respective polymer blend that comprises, further to the respective thermoplastic base polymer, between 1 and 10 weight percent of a high melt flow rate polymer based on total weight of said respective polymer blend; wherein the high melt flow rate polymer has a melt flow rate of between 600 and 3,000 g/10 min as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg; wherein the crimped multicomponent fibers have a linear mass density of between 0.6 and 1.5 denier; and wherein the average crimp number of the crimped multicomponent fibers is in the range of at least 5 crimps per cm in the fiber, as measured per Japanese standard JIS L-1015-1981 under a pre-tension load of 2 mg/denier.

2. The spunbonded nonwoven according to claim 1, wherein the high melt flow rate polymer has a melting point of greater 120° C. as measured according to ISO 11357-3.

3. The spunbonded nonwoven according to claim 1, wherein the melt flow rate of the high melt flow rate polymer is greater than 750 g/10 min as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg.

4. The spunbonded nonwoven according to claim 1, wherein the melt flow rate of the high melt flow rate polymer is smaller than 2,200 g/10 min, as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg.

5. The spunbonded nonwoven according to claim 1, wherein the level of incorporation of the high melt flow rate polymer in the first polymer material and/or the second polymer material is between 3 and 9 weight percent.

6. The spunbonded nonwoven according to claim 1, wherein the first base polymer and/or the second base polymer is a polyolefin.

7. The spunbonded nonwoven according to claim 1, wherein the high melt flow rate polymer is a polypropylene homopolymer.

8. The spunbonded nonwoven according to claim 1, wherein the first and/or the second polymer material further comprises a slip agent, wherein the slip agent is present in the respective polymer material in an amount of up to 5,000 ppm, based on the total weight of the respective polymer material.

9. The spunbonded nonwoven of claim 1, wherein the average crimp number of the crimped multicomponent fibers is in the range of at least 8 crimps per cm in the fiber, as measured per Japanese standard JIS L-1015-1981 under a pre-tension load of 2 mg/denier.

10. The spunbonded nonwoven according to claim 1, wherein the melt flow rate of the high melt flow rate polymer is greater than 1,000 g/10 min as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg.

11. The spunbonded nonwoven according to claim 1, wherein the melt flow rate of the high melt flow rate polymer is smaller than 1,800 g/10 min as measured according to ISO 1133 with conditions being 230° C. and 2.16 kg.

12. The spunbonded nonwoven according to claim 1, wherein the linear mass density of the crimped multicomponent fibers is between 0.8 and 1.35 denier.

13. The spunbonded nonwoven according to claim 6, wherein the polyolefin is a polypropylene homopolymer, a polyethylene homopolymer or a polypropylene-ethylene copolymer.

14. A multilayer fabric wherein at least one layer comprises a spunbonded nonwoven according to claim 1.

15. The multilayer fabric according to claim 14, wherein the multilayer fabric comprises at least two spunbonded nonwoven layers (S) and at least one meltblown nonwoven layer (M) in an SMS configuration.

16. A hygiene product comprising a spunbonded nonwoven according to claim 1 or a multilayer fabric having multiple layers and at least one layer comprises the spunbonded nonwoven.

17. A method for making the spunbonded nonwoven according to claim 1 in an apparatus comprising at least two extruders with a spinnerette, a drawing channel and a moving belt, wherein the fibers are spun in a spinnerette, drawn in a drawing channel and laid down on a moving belt, wherein the apparatus comprises a pressurized process air cabin from which process air is directed through the drawing channel to draw fibers, wherein the pressure difference between the ambient pressure and the pressure in the process air cabin is at least 4,000 Pascal and/or wherein the maximum air speed in the drawing channel is at least 70 m/s.

18. The method according to claim 17, wherein the pressure difference between the ambient pressure and the pressure in the process air cabin is at most 8,000 Pascal and/or wherein the maximum air speed in the drawing channel is at most 110 m/s and/or wherein the extruder temperature of at least one of the extruders is between 240° C. and 285° C.

Description

(1) Further details and advantages of the invention will in the following be described with reference to the figures and with reference to working examples. The figures show:

(2) FIG. 1: a schematic illustration of a spunbonding apparatus suitable for producing spunbonded nonwovens according to the invention;

(3) FIGS. 2A-2C: diagrams showing the outcome of a uniformity analysis for the nonwovens of Comparative Example C1 and Examples 2 and 3;

(4) FIGS. 3A-3C: diagrams showing the outcome of a uniformity analysis for the nonwovens of Comparative Example C4 and Example 7; and

(5) FIG. 4: sketches of side-by-side, eccentric sheath core and trilobal bicomponent fiber configurations.

(6) FIG. 1 shows an apparatus that is suitable for producing spunbonded nonwovens according to the invention. Spunbonded nonwovens are produced from continuous fibers 3 of thermoplastic material, which are spun in a spinnerette 1 and subsequently passed through a cooling device 2. A monomer suctioning device 4 to remove gases in the form of decomposition products, monomers, oligomers and the like generated during the spinning of the fibers 3 is arranged between the spinnerette 1 and the cooling device 2. The monomer suctioning device 4 comprises suction openings or suction gaps.

(7) In the cooling device 2, process air is applied to the fiber curtain from the spinnerette 1 from opposite sides. The cooling device 2 is divided into two sections 2a and 2b, which are arranged in series along the flow direction of the fibers. Thus, process air of a relatively higher temperature (for example 60° C.) can be applied to the fibers at an earlier stage in chamber section 2a and process air of a relatively lower temperature (for example 30° C.) can be applied to the fibers at a later stage in chamber section 2b. The supply of process air takes place via air supply cabins 5a and 5b, respectively. The cabin pressure within at least cabin 5b and preferably likewise chamber 5a, in agreement with the present invention, can be more than 4,000 Pascal above ambient pressure.

(8) A drawing device 6 to draw and stretch the fibers 3 is arranged below the cooling device 2. The drawing device includes an intermediate channel 7, which preferably converges and gets narrower with increasing distance from the spinnerette 1. It one embodiment the converging angle of the intermediate channel 7 can be adjusted. After the intermediate channel 7 the fiber curtain enters the lower channel 8.

(9) The cooling device 2 and the drawing device 6, including intermediate channel 7 and lower channel 8, are together formed as a closed aggregate, meaning that over the entire length of the aggregate, no major air flow can enter from the outside and no major process air supplied in the cooling device 2 can escape to the outside. Some fume extraction devices directly under the spinneret extracting a minor air volume can be incorporated.

(10) The fibers 3 leaving the drawing device 6 are then passed through a laying unit 9, which comprises two successively arranged diffusers 10 and 11 are provided, each diffuser 10 and 11 having a convergent section and an adjoining divergent section. The diffuser angles, in particular the diffuser angles in the divergent regions of the diffusers 10 and 11, are adjustable. Also, the position of the diffusers 10 and 11 and hence their distance from one another and from the spinbelt 13 can be adjusted. Between the diffusers 10 and 11 is a gap 15 through which ambient air is sucked into the fiber flow space.

(11) After passing through the laying unit 9, the fibers 3 are deposited as nonwoven web 12 on a spinbelt 13, formed from an air-permeable web. A suctioning device 16 is arranged below the laydown area of the spinbelt 13 so suck off process air, which is illustrated in FIG. 1 by the arrow A. Specifically, although this is not specifically illustrated in FIG. 1, a plurality of suctioning devices can be arranged in series along the moving direction of the spinbelt 13. The suctioning device 16 sifting directly below the laydown area is set to the highest air extraction speed, the subsequent suctioning device the second highest, and so forth.

(12) Once deposited the nonwoven web 12 is first guided through the gap between a pair of pre-consolidation rollers 14 for pre-consolidating the nonwoven web 12. Subsequently, at a position not shown in the figure, a further consolidation and bonding of the nonwoven web 12 will take place, for example by using calendar rolls, by using a hot air knive or through hydrodynamic consolidation.

(13) The following terms and abbreviations may be used in the working examples.

(14) MFR: Melt Flow Rate as measured according to ISO 1133 with values shown in g/10 min and conditions being 230° C. and 2.16 kg

(15) MD: Machine Direction

(16) CD: Cross machine Direction

(17) Denier: g/9000 m filament

(18) Caliper: Thickness of a nonwoven material when measured according to WSP.120.1 (R4), pressure of 0.5 kPa

(19) GSM: nonwoven basis weight in grams per square meter

(20) TM: melting point in ° C. as determined according to DSC (Differential Scanning Calorimetry) method ISO 11357-3

(21) MWD: Molecular Weight Distribution Mw/Mn, also referred to as the PD, the polydispersity index as measured according to ASTM D1238-13, where BHT-stabilized TCB was used as a solvent for the polymer, where the polymer concentration was 1.5 g/I and the measurement temperature was 160° C., and where the sensor was of IR type. The columns were calibrated by PS standards, with the results of the tests being converted by using the Mark Houwink equation with the parameter set PS: alpha=0.7/K=0.0138 \ PP: alpha=0.707/K=0.0242.
Opacity: expressed in average % as measured according to NWSP 060.1.R0 on a Hunter ColorFlex EZ Spectrophotometer
Crimp level: expressed in crimp/cm as measured according to Japanese standard JIS L-1015-1981 under a pre-tension load of 2 mg/denier on a Textechno Favimat+ using a sensitivity of 0.05 mm
Crimp amplitude: expressed in mm as measured according to Japanese standard JIS L-1015-1981 under a pre-tension load of 2 mg/denier on a Textechno Favimat+ using a sensitivity of 0.05 mm

(22) A number of crimped side-by-side was spun in a spunbonding machine as depicted in FIG. 1 using different polymer mixtures for both fiber zones and different machine settings. In FIG. 4 a typical side-by-side configuration is illustrated, along with known alternative configurations.

COMPARATIVE EXAMPLE C1 AND EXAMPLES 2-15 PP/COPP COMBINATIONS

(23) A first series of experiments is summarized in Table 1 below:

(24) TABLE-US-00001 Table 1 Fiber Cabin Ratio Throughput Prs. Ex. P1/P2 P1 P2 (g/hole/min) (Pa) C1 50/50 511A RP248R 0.55 3800  2 50/50 511A (95%) RP248R (95%) 0.45 6000 HL712FB (5%) HL712FB (5%)  3 50/50 511A (95%) RP248R (95%) 0.45 6000 S400 (5%) S400 (5%)  4 50/50 511A (95%) RP248R (95%) 0.45 5000 HL712FB (3%) HL712FB (3%)  5 50/50 511A (95%) RP248R (95%) 0.45 5000 HL712FB (5%) HL712FB (5%)  6 50/50 511A (95%) RP248R (95%) 0.45 7400 HL712FB (5%) HL712FB (5%)  7 50/50 511A (92%) RP248R (92%) 0.45 5000 HL712FB (8%) HL712FB (8%)  8 50/50 511A (92%) RP248R (92%) 0.45 7800 HL712FB (8%) HL712FB (8%)  9 50/50 511A (92%) RP248R (92%) 0.52 5000 HL712FB (8%) HL712FB (8%) 10 50/50 511A (92%) RP248R (92%) 0.52 6000 HL712FB (8%) HL712FB (8%) 11 50/50 511A (92%) RP248R (92%) 0.52 8000 HL712FB (8%) HL712FB (8%) 12 50/50 511A (95%) RP248R (95%) 0.45 5000 MF650X (5%) MF650X (5%) 13 50/50 511A (92%) RP248R (92%) 0.45 5000 MF650X (8%) MF650X (8%) 14 50/50 511A (95%) RP248R (95%) 0.45 5000 HL708FB (5%) HL708FB (5%) 15 50/50 511A (92%) RP248R (92%) 0.45 5000 HL708FB (8%) HL708FB (8%)

(25) On the Reicofil machine used for the experiments and at an SAS gap of 22 mm, the cabin pressure of 3,800 Pa applied in Comparative Example C1 resulted in a maximum air speed of approx. 75 m/s and an air volume flow of approx 7,500 m.sup.3/h in the drawing channel. A cabin pressure of 6,000 Pa applied in Examples 2-15 resulted in a maximum air speed of approx. 95 m/s and an air volume flow of approx 9,500 m.sup.3/h in the drawing channel.

(26) The polymer materials used in the experiments were the following: The material 511A is a homo-polypropylene from Sabic with a MWD of 3-5 (manufacturer indication) and a MFR of 25 g/10 min. It has a melting temperature of between 160-166° C. The material RP248R is a random polypropylene-ethylene copolymer from Lyondellbasell with a MWD of 3-5, a MFR of 30 g/10 min and a melting temperature of 144° C. The material HL712FB is a Ziegler-Natta polypropylene homopolymer from Borealis with a narrow MWD, a MFR of 1,200 g/10 min and a melting temperature of 158° C. The material MF650X is a Metallocene polypropylene homopolymer from LyndonellBasell with a MFR of 1,200 g/10 min and a melting temperature of greater 150° C. The material HL708FB is a Ziegler-Natta polypropylene homopolymer from Borealis with a MFR of 800 g/10 min and a melting temperature of 158° C. The material S400 is a low molecular weight polyolefin from Idemitsu, a MWD of 2, a MFR of >2,000 g/10 min and a melting point of 80° C. (as determined to a test standard of the manufacturer Idemitsu).

(27) In Comparative Example C1, the cabin pressure of 3,800 Pa is the maximum cabin pressures that could be used with the given polymers. Higher cabin pressures resulted in unstable spinning conditions and let to fiber breakage and drop forming. In the inventive Examples 2-15, cabin pressures of 5,000 Pa and higher could be used at stable spinning conditions and without causing any filament breakage or forming of drops.

(28) In all, Comparative Example C1 and Examples 2-15, the nonwoven materials were thermally bonded with a heated calendar steel roller with an open dot bonding pattern with an bonding area of 12% and a point bond concentration of 24 dots/cm.sup.2 running against a smooth steel roller. The temperature of the patterned roller was set to 140° C., the temperature of the smooth roller was set to 135° C. and the linear contact force was kept constant at 60 daN/cm.

(29) The properties of the resultant spunbond nonwoven materials are summarized in Tables 2-4 below.

(30) TABLE-US-00002 Table 2 Basis Weight Thickness Density Denier Uniformity Ex. (g/m.sup.2) (mm) (mg/cm.sup.3) (g/9000 m) Index/slope Cl 19.7 0.43 45.8 1.48 270.257 2 20.9 0.44 47.5 1.05 278.633 3 21.1 0.48 44.0 1.10 280.377 4 20.1 0.33 60.9 1.19 5 19.9 0.36 55.3 1.32 6 20.0 0.33 60.6 1.10 7 20.0 0.38 52.6 1.13 8 20.0 0.33 60.6 1.04 9 20.0 0.41 48.8 1.31 10 20.0 0.38 52.6 1.27 11 20.0 0.35 57.1 1.12 12 18.0 0.25 72.0 1.27 13 18.0 0.35 51.4 1.19 14 18.0 0.34 52.9 1.17 15 18.0 0.35 51.4 1.16

(31) TABLE-US-00003 Table 3 TSMD TEMD TSCD TECD Ex. (N/50 mm) (%) (N/50 mm) (%) Cl 23.5 154 13.6 180 2 29.0 140 16.0 168 3 30.8 160 16.0 191 4 27.4 129 17.1 163 5 27.4 133 15.5 141 6 34.1 123 19.6 156 7 24.8 122 14.5 143 8 34.3 111 19.3 143 9 23.1 119 13.2 152 10 26.2 115 15.5 145 11 32.3 116 17.1 138 12 26.4 135 15.0 163 13 26.6 145 14.6 176 14 26.6 135 16.4 171 15 25.4 129 15.1 170

(32) TABLE-US-00004 Table 4 Crimp level Crimp amplitude Opacity Ex. (crimps/cm) (mm) (%) Cl 9.03 0.29 22.22 2 14.30 0.26 28.37 3 15.26 0.21 28.03 4 12.07 0.19 N/A 5 11.40 0.18 N/A 6 11.80 0.18 N/A 7 14.00 0.20 N/A 8 N/A N/A N/A 9 N/A N/A N/A 10 N/A N/A N/A 11 N/A N/A N/A 12 11.40 0.23 N/A 13 9.42 0.19 N/A 14 9.10 0.19 N/A 15 9.90 0.19 N/A N/A indicates that a property was not determined experimentally for that respective sample.

(33) The product of Comparative Example C1 comprises crimped fibers in the normal denier range of about 1.5, which is a typical minimum value achievable with conservative crimped spunbond technology. Attempts to obtain lower denier fibers by simply increasing cabin pressure are unsuccessful because this will lead to fiber breakage. The inventive Examples 2-15 allow machine settings to be adapted to obtain lower denier fibers that still generate spontaneous crimp.

(34) As apparent from Table 2, the addition of only 5% of a high MFR polypropylene additive to the polymers for both fiber sections leads to a material combination where higher cabin pressures can stably be used to obtain lower denier materials. The thicknesses and densities for the inventive Examples 2-15, respectively, indicate that the overall crimp level of the fibers remains unchanged despite the lower denier, which is important to the softness of the material. The measured values for crimp numbers and crimp amplitudes confirm this observation. A shift to a larger number of smaller amplitude crimps, so a shift to finer crimps can be observed, which has, however, no apparent negative influence on loft.

(35) As apparent from Table 3, for these PP/Co-PP materials, tensile properties are even improved in the inventive Examples 2-15 over the reference material of Comparative Example C1. An increase in both TSMD and TSCD is noted. The comparison is significant because the materials all have similar thicknesses and basis weights. The improvement in tensile properties is surprising because it would be expected that adding high MFR polymers such as HL712FB or S400 to the polymer streams should have a negative impact to the tensile strength of the individual fibers, especially as they are thinner. It is suspected, however, that this possible decrease in single fiber stability is usually overcompensated by an increase in the number of fibers.

(36) Also, the uniformity improved significantly in the inventive Examples 2 and 3, for which this property was measured, over Comparative Example C1. This is believed to be due to the lower denier range and at the same time due to less fiber collisions and more available air volume at the diffusors, which ultimately stands in connection with the higher cabin pressure. Specifically, to determine the uniformity of the laydown, a scan of the nonwovens with a subsequent analysis of the scan on a greyscale pixel level is performed. A material sheet having A3 size was scanned to obtain a greyscale image of 3510×4842, i.e., close to 17 million pixels. Each single pixel was then rated 0 to 255 with 0 being totally black level and 255 being white. The outcome of this analysis for the nonwovens of Comparative Example C1 and Examples 2 and 3 can be illustrated in the diagrams of FIGS. 2A to 2C. In FIG. 2A, the pixel count (y-axis) has been plotted against the pixel rating (x-axis) for each example. FIG. 2B shows a curve obtained by integrating the plot of FIG. 2A, where the y-axis then shows the sum of all pixels of a rating lower or equivalent to the current position on the x-axis. FIG. 2C analyzes the slope of the curve of FIG. 2B in the section between y=2.10.sup.6 to y=15.10.sup.6. One thing that can be noted from FIG. 2A is that the peak becomes higher in Examples 2 and 3. Because the same amount of pixels is evaluated in either case, a higher peak corresponds to a narrower distribution in pixel rating, which in turn points to a more uniform material. Another thing that can be noted is that the curves of Examples 2 and 3 are narrower in the boundary areas where pixel counts are lower than 50.000, meaning that there are less “extreme” areas of fiber densities that are much lower or much higher than average. Both these findings are confirmed in FIG. 2B and particularly FIG. 2C, where the higher pixel slope measured in FIG. 2C quantifies the visual finding of a more uniform distribution. Yet another thing that can be noted from the FIGS. 2A-2C is that the average greyscale in Examples 2 and 3 is higher than in Comparative Example C1. This is a consequence of the thinner fiber diameters and the generally more dense appearance, although the actual density expressed in g/cm.sup.3 remains more or less unchanged. The latter finding is confirmed by the higher opacity values obtained for Examples 2-3.

COMPARATIVE EXAMPLE C16 AND EXAMPLES 17-27 PP/PP COMBINATIONS

(37) A second series of experiments is summarized in Table 5 below:

(38) TABLE-US-00005 Table 5 Fiber Cabin Ratio Throughput Prs. Ex. P1/P2 P1 P2 (g/hole/min) (Pa) C16 70/30 3155 3155 (75%) 0.52 3200 552N (25%) 17 70/30 3155 (88%) HG475FB (68%) 0.45 6000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 18 70/30 3155 (91%) HG475FB (66%) 0.45 6000 S400 (5%) 552R (25%) Soft (4%) S400 (5%) Soft (4%) 19 70/30 HG475FB (88%) HG475FB (71%) 0.45 6000 HL712FB (8%) 552R (25%) Soft (4%) Soft (4%) 20 70/30 3155 (93%) HG475FB (70%) 0.45 5000 HL712FB (3%) 552R (25%) Soft (4%) HL712FB (1%) Soft (4%) 21 70/30 3155 (91%) HG475FB (69%) 0.45 5000 HL712FB (5%) 552R (25%) Soft (4%) HL712FB (2%) Soft (4%) 22 70/30 3155 (88%) HG475FB (68%) 0.45 5000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 23 70/30 3155 (88%) HG475FB (68%) 0.45 6000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 24 70/30 3155 (88%) HG475FB (68%) 0.45 8000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 25 70/30 3155 (88%) HG475FB (68%) 0.52 5000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 26 70/30 3155 (88%) HG475FB (68%) 0.52 6000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%) 27 70/30 3155 (88%) HG475FB (68%) 0.52 9000 HL712FB (8%) 552R (25%) Soft (4%) HL712FB (3%) Soft (4%)

(39) The cabin pressure of 3200 Pa applied in Comparative Example C16 resulted in maximum air speeds and an air volume flow only slightly lower than in Comparative Example C1 described above. In the inventive Examples 17-27 the maximum air speeds and air volume flows were higher.

(40) The polymer materials used in the experiments were the following: The material 3155 is a homo-polypropylene from Exxonmobil with a MWD of 3-5 and a MFR of 35 g/10 min. The material 552N is a homo-polypropylene from Lyondellbasell with a MWD of 5-7 and a MFR of 13 g/10 min. The material 552R is a homo-polypropylene from Lyondellbasell with a MWD of 5-7 and a MFR of 25 g/10 min. The material HG475FB is a homo-polypropylene from Borealis with a MWD of 3-5 and a MFR of 27 g/10 min. All these homo-polypropylenes have melting points in the area of between 160-166° C. The material Soft is a slip agent with 10% Erucamide in a polypropylene masterbatch (Constab SL 05068PP). The materials HL712FB and S400 are as described above.

(41) In Comparative Example C16, the cabin pressure of 3200 Pa is the maximum cabin pressures that could be used with the given polymers. Higher cabin pressures resulted in unstable spinning conditions and let to fiber breakage and drop forming. In the inventive Examples 17-27 a cabin pressure of 6,000 Pa could be used at stable spinning conditions and without causing any filament breakage or forming of drops.

(42) Other settings were similar to Examples C1/2-15, with the exception that the temperature and linear pressure conditions of the calendar rolls were modified to account for the polypropylene-only nature of these materials.

(43) The properties of the resultant spunbond nonwoven materials are summarized in Tables 6-8 below.

(44) TABLE-US-00006 Table 6 Basis Thickness Density Denier Uniformity Ex. Weight (g/m.sup.2) (mm) (mg/cm.sup.3) (g/9000 m) Index/slope C16 23.6 0.58 40.7 1.79 270.354 17 26.4 0.60 44.0 1.13 N/A 18 25.4 0.57 44.6 1.16 N/A 19 19.7 0.55 35.8 1.16 288.198 20 23.9 0.64 37.3 1.16 N/A 21 23.7 0.63 39.6 1.15 N/A 22 25.0 0.58 43.1 1.29 N/A 23 25.0 0.56 44.6 1.14 N/A 24 25.0 0.53 47.2 1.04 N/A 25 25.0 0.57 43.9 1.45 N/A 26 25.0 0.57 43.9 1.37 N/A 27 25.0 0.55 45.5 1.09 N/A

(45) TABLE-US-00007 Table 7 TSMD TEMD TSCD TECD Ex. (N/50 mm) (%) (N/50 mm) (%) C16 19.2 158 10.4 192 17 28.9 150 25.6 177 18 34.9 153 19.6 189 19 17.6 212 9.1 247 20 25.2 200 13.6 257 21 26.7 196 14.0 222 22 23.2 177 12.4 225 23 24.3 188 11.6 234 24 23.3 180 11.3 241 25 22.1 147 11.5 171 26 20.5 183 11.8 234 27 21.7 164 10.1 176

(46) TABLE-US-00008 Table 8 Crimp level Crimp amplitude Opacity Ex. (crimps/cm) (mm) (%) C16 N/A N/A N/A 17 10.70 0.29 37.69 18 13.38 0.25 35.54 19 13.38 N/A 31.94 20 14.70 0.22 N/A 21 13.40 0.21 N/A 22 16.20 0.20 N/A 23 20.07 0.15 N/A 24. N/A N/A N/A 25 N/A N/A N/A 26 N/A N/A N/A 27 N/A N/A N/A N/A indicates that a property was not determined experimentally for that respective sample.

(47) Similar to the observations that could be made to Example C1/2-15, the product of Comparative Example C16 comprises a higher fiber diameter of about 1.8 denier, while denier could be significantly decreased in Examples 17-27.

(48) The addition of small amounts of a high MFR polypropylene additive to the polymers for both fiber sections (Examples 17-18, 20-27) or even only the more voluminous fiber section (Example 19) leads to a material combination where higher cabin pressures can stably be used to obtain lower denier materials. The material thicknesses remain essentially unchanged despite the lower denier. The tensile properties are improved in some inventive Examples over the reference material of Comparative Example C16 and in some instances an increase in both TSMD and TSCD is noted. In all inventive Examples, they are at least not decreased, despite the sometimes lower basis weight.

(49) While no crimp level or opacity measurements for Comparative Example C16 have been carried out, the data for Examples 17-18 are similar to the data for Examples 2-3 and are hence representative for the desired beneficial outcome.

(50) Uniformity measurements comparing Comparative Example 16 and Example 19 are depicted in FIGS. 3A-3C. Like in the case of Examples C1/2-3, an improvement is clearly visible.

(51) The perceived softness of the materials of all Inventive Examples 2-15 and 17-27 is very high and similar to the perceived softness of a microfleece woven web, which by many in the hygiene industry is viewed as the ultimately material when it comes to ratings of softness for the use in personal care products like baby diapers, feminine care protection pads and adult incontinence hygiene products.