Dual-sided and multi-layer nonwoven fabric

Abstract

A nonwoven material is disclosed having an excellent balance between strength and softness. The nonwoven material can be made from spunbond layers and can include at least one strength-building layer combined with at least one softness enhancing layer. In one aspect, the nonwoven material can be incorporated into an elastic laminate for use in absorbent articles. The nonwoven material contains at least one layer compatibilizer that increases the bond strength or attachment strength between the strength building layer and the softness enhancing layer. The layer compatibilizer was also found to unexpectedly improve abrasion resistance.

Description

[0001] DUAL-SIDED AND MULTI-LAYER NONWOVEN FABRIC

[0002] BACKGROUND

[0003] Spunbond nonwoven fabrics comprise bonded webs of continuous filaments formed by extruding a molten thermoplastic polymer from a plurality of fine capillaries as molten filaments. The molten filaments are quenched to at least partially solidify them and then they are attenuated by one or more high velocity air streams which reduce their diameter. By way of example, spunbond filament nonwoven webs and processes for making the same are disclosed in US4340563 to Appel et al, US5382400 to Pike et al.; US8246898 to Conrad et al. and US8333918 to Lennon et al., which are all incorporated herein by reference.

[0004] Spunbond filament nonwoven webs are commonly used in a wide range of products. The reason for this extensive and varied use in part relates to the ability of spunbond filament nonwoven webs to provide a desirable combination of properties. Further, the cost of manufacture of spunbond filament webs is relatively low as compared to other materials with like properties such as traditional knitted or woven fabrics. As a result, spunbond filament nonwoven webs have been found to be particularly useful in relation to the manufacture of single-use or limited-use products; e.g. absorbent personal care products, wipes, protective apparel, geotextiles, tarpaulins, etc.

[0005] The properties of spunbond webs can be varied by changing the polymer composition that is used to produce the web. For example, producing spunbond webs from elastomeric materials can result in webs having a soft handfeel and excellent drapeability characteristics. Elastic spunbond webs, however, tend to lack strength and durability in relation to spunbond webs made from other polymer materials.

[0006] In order to produce a spunbond nonwoven fabric having strength in combination with softness, the fabric can be produced from multiple layers of spunbond nonwoven webs. For instance, a spunbond nonwoven web having high strength can be combined with a spunbond nonwoven web having excellent softness characteristics. Unfortunately, however, combining webs having different characteristics tend to be incompatible. Thus, multi-layer spunbond nonwoven fabrics made in the past had a tendency to delaminate or exhibited poor peel strength. Thus, a need currently exists for a multi-layer spunbond nonwoven fabric containing dissimilar nonwoven webs having different characteristics that can be combined together in a way that produces a consolidated nonwoven that is resistant to delamination. SUMMARY

[0007] In general, the present disclosure is directed to producing multi-layer nonwoven fabrics having a good balance of softness and strength in combination with excellent interlayer bonding strength. In one aspect, for instance, nonwoven materials or fabrics are made according to the present disclosure including a facing made from a soft-elastic spunbond web. The nonwoven fabric further includes at least one other strength-building layer, which can also be made from a spunbond web. The nonwoven fabric is particularly well suited for producing elastic laminates in which the strength-building layer is positioned against an elastic film or strands with the soft-elastic spunbond layer forming a top layer of the laminate that has soft, cloth-like properties.

[0008] In one embodiment, for instance, the present disclosure is directed to a nonwoven material. The nonwoven material includes a strength-building layer comprising spunbond fibers randomly arranged to form a web. The spunbond fibers can be made from a non-elastomeric polymer. For example, the non-elastomeric polymer can be a polypropylene polymer and can comprise at least about 70%, such as at least about 80%, such as at least about 90% of the strength-building layer.

[0009] The nonwoven material further includes a softness enhancing layer comprising spunbond fibers randomly arranged to form a web. The softness enhancing layer can be incorporated into the nonwoven material so as to form a top layer of the material. The softness enhancing layer is bonded to the strength-building layer. The spunbond fibers in the softness enhancing layer can comprise elastomeric containing fibers. For example, the elastomeric containing fibers can be made from elastomeric containing bicomponent fibers including a core surrounded by a sheath. The core of the bicomponent fibers, in one embodiment, can be formed from a polypropylene-based elastomer alone or in combination with a secondary amide. The polypropylene-based elastomer can comprise an ethylene comonomer, an a-olefin comonomer, or a combination thereof. The sheath, on the other hand, can comprise a non-elastomeric polymer. For instance, the sheath can be made from a polyethylene polymer.

[0010] In accordance with the present disclosure, the nonwoven material further comprises a layer compatibilizer that improves bonding between the strength building layer and the softness enhancing layer. The layer compatibilizer, for instance, can be contained in the spunbond fibers of the strength building layer or can be contained in the spunbond fibers of the softness enhancing layer. In one aspect, the layer compatibilizer can increase the peel strength between the strength building layer and the softness enhancing layer. For instance, the nonwoven material can display a peel peak load of greater than about 150 gf, such as greater than about 200 gf, such as greater than about 250 gf, such as greater than about 275 gf, such as greater than about 300 gf. In one aspect, the peel strength can be increased to a point where the test for determining peel strength is not measurable because the bond strength between the two layers is stronger than the strength of each individual layer. For instance, during the peel strength test, the nonwoven material can rip apart as opposed to delaminating where the two layers meet.

[0011] In one aspect, the layer compatibilizer can also increase the abrasion resistance of the nonwoven material, such as the softness enhancing layer, which is unexpected in view of increasing peel strength. For instance, the abrasion resistance is increased without changing the surface characteristics or composition of the softness enhancing layer.

[0012] In one aspect, the layer compatibilizer comprises a polymer of the same type that is exposed on a surface of the adjoining layer. As used herein, “polymers of the same type” refers to two polymers in which the primary monomer in each polymer is the same.

[0013] In one aspect, the spunbond fibers contained in the strength building layer are made from a polypropylene polymer. The spunbond fibers contained in the softness enhancing layer, on the other hand, can comprise elastomeric bicomponent fibers. The elastomeric bicomponent fibers can include a core surrounded by a sheath. In one embodiment, the sheath of the elastomeric bicomponent fibers of the softness enhancing layer can comprise a polyethylene polymer. The layer compatibilizer can comprise a polyethylene polymer contained in the spunbond fibers of the strength building layer. For example, in one aspect, the spunbond fibers of the strength building layer can comprise bicomponent fibers containing a core comprising the polypropylene polymer. The sheath surrounding the core can comprise the layer compatibilizer. The layer compatibilizer, for instance, can comprise a polyethylene homopolymer or a polyethylene copolymer containing ethylene in an amount greater than about 80% by weight. In one particular embodiment, the layer compatibilizer comprises a low density polyethylene, such as a linear low density polyethylene. The layer compatibilizer can be contained in the spunbond fibers of the strength building layer in an amount from about 5% to about 55% by weight, such as in an amount from about 10% by weight to about 50% by weight, such as in an amount from about 20% by weight to about 40% by weight.

[0014] In an alternative embodiment, the layer compatibilizer can be contained in the sheath of the spunbond fibers of the softness enhancing layer. For instance, in this embodiment, the layer compatibilizer can comprise a polypropylene polymer. The polypropylene polymer can be a polypropylene homopolymer or copolymer. The polypropylene copolymer, for instance, can contain propylene in an amount greater than about 80% by weight. The layer compatibilizer can be contained in the sheath of the spunbond fibers of the softness enhancing layer in an amount from about 8% to about 100% by weight, such as in an amount from about 10% to about 50% by weight, such as in an amount from about 10% to about 30% by weight. The sheath of the spunbond fibers of the softness enhancing layer can also contain a non-elastomeric polymer in combination with the layer compatibilizer. The non-elastomeric polymer, for instance, may comprise a polyethylene polymer.

[0015] As described above, the spunbond fibers of the strength building layer can comprise a polypropylene polymer while the elastomeric bicomponent spunbond fibers of the softness enhancing layer can include a sheath comprising a polyethylene polymer and a core comprising a polypropylene- based elastomer and a secondary amide.

[0016] The secondary amide, for instance, can have a chemical structure as follows: wherein,

[0017] R14, R15, R , and Rie are independently selected from C7-C27 alkyl groups and C7-C27 alkenyl groups; and

[0018] R17 is selected from C8-C28 alkyl groups and C8-C28 alkenyl groups.

[0019] The basis weight of the nonwoven material made in accordance with the present disclosure can vary depending upon the particular application and the desired result. In general, the basis weight of the nonwoven material can be anywhere from about 5 gsm to about 300 gsm, including all increments of 1 gsm therebetween. In certain embodiments, the basis weight can be from about 5 gsm to about 170 gsm, such as from about 9 gsm to about 20 gsm. The weight ratio between the strength-building layer and the softness enhancing layer within the nonwoven material can be from about 1 :3 to about 1.5:1 , such as from about 1 :2 to about 1.1 :1.

[0020] The present disclosure is also directed to an elastomeric laminate containing the nonwoven material as described above. In one aspect, the elastomeric laminate can include an elastic backing that can be made from an elastic film or a plurality of parallel elastic strands, such as filaments or ribbons. In one aspect, the strength-building layer can be adhered to the backing. The softness enhancing layer, on the other hand, can form an exterior surface of the elastomeric laminate.

[0021] Other features and aspects of the present disclosure are discussed in greater detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

[0023] Figures 1 a and 1 b are example fibers for use in nonwoven materials made according to the present disclosure;

[0024] Figure 2 is an example schematic of an apparatus for forming an extensible facing;

[0025] Figure 3 is an example of a schematic of an apparatus for forming a strength-building layer;

[0026] Figure 4 is an example schematic of an apparatus for forming a nonwoven material in accordance with the present disclosure;

[0027] Figure 5 is a plan view of some of the results obtained in the example below after an abrasion test; and

[0028] Figure 6 is a plan view of some of the results obtained in the example below after an abrasion test.

[0029] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

[0030] DEFINITIONS

[0031] As used herein, the terms "about," “approximately,” or “generally,” when used to modify a value, indicates that the value can be raised or lowered by 10%, such as, such as 7.5%, 5%, such as 4%, such as 3%, such as 2%, such as 1 %, and remain within the disclosed aspect. Moreover, the term “substantially free of’ when used to describe the amount of substance in a material is not to be limited to entirely or completely free of and may correspond to a lack of any appreciable or detectable amount of the recited substance in the material. Thus, e.g., a material is “substantially free of” a substance when the amount of the substance in the material is less than the precision of an industry- accepted instrument or test for measuring the amount of the substance in the material. In certain example embodiments, a material may be “substantially free of” a substance when the amount of the substance in the material is less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4%, less than 3%, less than 2%, less than 1 %, less than 0.5%, or less than 0.1 % by weight of the material

[0032] As used herein, the term “elastomeric” and “elastic” and refers to a material that, upon application of a stretching force, is stretchable in at least one direction (such as the CD or MD direction), and which upon release of the stretching force, contracts / returns to approximately its original dimension. For example, a stretched material may have a stretched length that is at least 50% greater than its relaxed unstretched length, and which will recover to within at least 50% of its stretched length upon release of the stretching force. A hypothetical example would be a one (1) inch sample of a material that is stretchable to at least 1 .50 inches and which, upon release of the stretching force, will recover to a length of not more than 1 .25 inches. Desirably, the material contracts or recovers at least 50%, and even more desirably, at least 80% of the stretched length.

[0033] As used herein, the term “fibers” generally refer to elongated extrudates that may be formed by passing a polymer through a forming orifice, such as a die. Unless noted otherwise, the term “fibers” includes discontinuous fibers having a definite length (e.g., stable fibers) and substantially continuous filaments. Substantially continuous filaments may, for instance, have a length much greater than their diameter, such as a length to diameter ratio (“aspect ratio”) greater than about 15,000 to 1 , and in some cases, greater than about 50,000 to 1.

[0034] As used herein the term “extensible” generally refers to a material that stretches or extends in the direction of an applied force (e.g., CD or MD direction) by about 50% or more, in some aspects about 75% or more, in some aspects about 100% or more, and in some aspects, about 200% or more of its relaxed length or width.

[0035] As used herein, the terms “necked” and “necked material” generally refer to any material that has been drawn in at least one dimension (e.g., machine direction) to reduce its transverse dimension (e.g., cross machine direction) so that when the drawing force is removed, the material may be pulled back to its original width. The necked material generally has a higher basis weight per unit area than the un-necked material. When the necked material is pulled back to its original width, it should have about the same basis weight as the un-necked material. This differs from the orientation of a film in which the film is thinned and the basis weight is reduced. The necking method typically involves unwinding a material from a supply roll and passing it through a brake nip roll assembly driven at a given linear speed. A take-up roll or nip, operating at a linear speed higher than the brake nip roll, draws the material and generates the tension needed to elongate and neck the material.

[0036] As used herein the term “nonwoven web” generally refers to a web having a structure of individual fibers or threads which are interlaid, but not in an identifiable manner as in a knitted fabric. Examples of suitable nonwoven fabrics or webs include, but are not limited to, meltblown webs, spunbond webs, bonded carded webs, airlaid webs, coform webs, hydraulically entangled webs, and so forth.

[0037] As used herein, the term “meltblown web” generally refers to a nonwoven web that is formed by a process in which a molten thermoplastic material is extruded through a plurality of fine, usually circular, die capillaries as molten fibers into converging high velocity gas (e.g., air) streams that attenuate the fibers of molten thermoplastic material to reduce their diameter, which may be to microfiber diameter. Thereafter, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a web of randomly dispersed meltblown fibers. Such a process is disclosed, for example, in U.S. Patent No. 3,849,241 to Butin, et al., which is incorporated herein in its entirety by reference thereto for all purposes. Generally speaking, meltblown fibers may be microfibers that are substantially continuous or discontinuous, generally smaller than 10 microns in diameter, and generally tacky when deposited onto a collecting surface.

[0038] As used herein, the term “spunbond web” generally refers to a web containing small diameter substantially continuous fibers. The fibers are formed by extruding a molten thermoplastic material from a plurality of fine, usually circular, capillaries of a spinnerette with the diameter of the extruded fibers then being rapidly reduced as by, for example, eductive drawing and / or other well-known spunbonding mechanisms. The production of spunbond webs is described and illustrated, for example, in U.S. Patent Nos. 4,340,563 to Appel, et al., 3,692,618 to Dorschner, et al., 3,802,817 to Matsuki, et al., 3,338,992 to Kinney, 3,341 ,394 to Kinney, 3,502,763 to Hartman, 3,502,538 to Levy, 3,542,615 to Dobo, et al., and 5,382,400 to Pike, et al., which are incorporated herein in their entirety by reference thereto for all purposes. Spunbond fibers are generally not tacky when they are deposited onto a collecting surface. Spunbond fibers may sometimes have diameters less than about 40 microns, and are often between about 5 to about 20 microns.

[0039] As used herein, the terms “machine direction” or “MD” generally refers to the direction in which a material is produced (e.g., the direction the material is conveyed during the forming / manufacturing process of the nonwoven material). The term “cross-machine direction” or “CD” refers to the direction perpendicular to the machine direction.

[0040] As used herein, the term “thermal point bonding” generally refers to a process performed, for example, by passing a material between a patterned roll (e.g., calender roll) and another roll (e.g., anvil roll), which may or may not be patterned. One or both of the rolls are typically heated.

[0041] As used herein, the term “ultrasonic bonding” generally refers to a process performed, for example, by passing a material between a sonic horn and a patterned roll (e.g., anvil roll). For instance, ultrasonic bonding through the use of a stationary horn and a rotating patterned anvil roll is described in U.S. Patent Nos. 3,939,033 to Grgach, et al., 3,844,869 to Rust Jr., and 4,259,399 to Hill, which are incorporated herein in their entirety by reference thereto for all purposes. Moreover, ultrasonic bonding through the use of a rotary horn with a rotating patterned anvil roll is described in U.S. Patent Nos. 5,096,532 to Neuwirth, et al., 5,110,403 to Ehlert, and 5,817,199 to Brennecke, et al., which are incorporated herein in their entirety by reference thereto for all purposes. Of course, any other ultrasonic bonding technique may also be used in the present disclosure.

[0042] As used herein "continuous filaments" means filaments formed in a substantially continuous, uninterrupted manner having indefinite length and having a high aspect ratio (length to diameter) in excess of about 10,000:1.

[0043] As used herein, the term "polymer" generally includes but is not limited to, homopolymers, copolymers, such as for example, block, graft, random and alternating copolymers, terpolymers, etc. and blends and modifications thereof. Furthermore, unless otherwise specifically limited, the term "polymer" shall include all possible geometrical configurations of the molecule. These configurations include, but are not limited to isotactic, syndiotactic and random symmetries.

[0044] As used herein "ethylene polymer" or "polyethylene" means a polymer having greater than 50 mol. % units derived from ethylene.

[0045] As used herein "olefin polymer" or "polyolefin polymer" means a polymer having greater than 50 mol. % units derived from an alkene, including linear, branched or cyclic alkenes.

[0046] As used herein "propylene polymer" or "polypropylene" means a polymer having greater than 50 mol. % units derived from propylene.

[0047] As used herein "personal care articles" means any and all articles or products used for personal health or hygiene including diapers, adult incontinence garments, absorbent pants and garments, tampons, feminine pads and liners, bodily wipes (e.g. baby wipes, perineal wipes, hand wipes, etc.), bibs, changing pads, bandages, and components thereof.

[0048] As used herein "protection articles" means all articles intended to protect a user or equipment from contact with or exposure to external matter including, for example, face masks, protective gowns and aprons, gloves, caps, shoe covers, equipment covers, sterile wrap (e.g. for medical instruments), car covers, and so forth.

[0049] Air Permeability Test

[0050] The Air Permeability Test measures the rate of air-flow through a known dry specimen area. The air permeability of each sample was measured using a Textest FX3300 air permeability tester available from Schmid Corporation, having offices in Spartanburg, S.C.

[0051] A specimen from each test sample was cut and placed so that the specimen extended beyond the clamping area of the air permeability tester. The test specimens were obtained from areas of the sample that were free of folds, crimp lines, perforations, wrinkles, and / or any distortions that make them abnormal from the rest of the test material. The tests were conducted in a standard laboratory atmosphere of 23±1 °C (73.4±1.8°F) and 50+2% humidity. The instrument was turned on and allowed to warm up for at least 5 minutes before testing any specimens. The instrument was calibrated based on the manufacturer's guidelines before the test material was analyzed. The pressure sensors of the instrument were reset to zero by pressing the NULL RESET button on the instrument. Before testing, and if necessary between samples or specimens, the dust filter screen was cleaned, following the manufacturer's instructions. The following specifications were selected for data collection: (a) Unit of measure: cubic feet per minute (cfm); (b) test pressure: 125 Pascal (water column 0.5 inch or 12.7 mm); and (c) test head: 38 square centimeters (cm.sup.2). Since test results obtained with different size test heads are not always comparable, samples to be compared should be tested with the same size test head.

[0052] The NULL RESET button was pressed prior to every series of tests, or when the red light on the instrument was displayed. The test head was open (no specimen in place) and the vacuum pump was at a complete stop before the NULL RESET button was pressed.

[0053] Each specimen was placed over the lower test head of the instrument. The test was started by manually pressing down on the clamping lever until the vacuum pump automatically started. The Range Indicator light on the instrument was stabilized in the green or yellow area using the RANGE knob. After the digital display was stabilized, the air permeability of the specimen was displayed, and the value was recorded. The test procedure was repeated for 10 specimens of each sample, and the average value for each sample was recorded as the air permeability.

[0054] Burst Strength Test

[0055] The Burst Strength Test measures the amount of force required to burst (i.e., rupture) a test sample using a constant rate of extension (CRE) tensile tester. The burst strength of each sample was measured using an MTS Criterion Model 42 tensile tester commercially available from MTS Systems Corporation.

[0056] A 4 inch by 4 inch (101.6 mm.times.101.6 mm) test specimen was cut from each test sample, and placed in a clamping fixture having a circular opening defining the test area. A penetration assembly having a smooth, spherical probe tip was arranged perpendicular to and centered under the circular test area. The penetration assembly consisted of a spherical probe tip affixed to the end of a socket, which was secured to the tensile tester with a lock nut. The Burst Strength Test was carried out according to TAPPI T570 pm-00, using a test speed of 6 inches per minute and a load cell of 50 Newtons. The penetration assembly was raised at the specified test speed such that the spherical probe tip contacted and eventually penetrated the test specimen to the point of specimen rupture. The maximum force applied by the penetration assembly at the instant of specimen rupture was recorded as the burst strength in grams-force (gf). The average value from 10 specimens of each test sample was recorded.

[0057] Stretch to Stop Test

[0058] "Stretch-to-stop" refers to a ratio determined from the difference between the unextended dimension of a stretchable laminate and the maximum extended dimension of a stretchable laminate upon the application of a specified tensioning force and dividing that difference by the unextended dimension of the stretchable laminate. If the stretch-to-stop is expressed in percent, this ratio is multiplied by 100. For example, a stretchable laminate having an unextended length of 5 inches (12.7 cm) and a maximum extended length of 10 inches (25.4 cm) upon applying a force of 2000 grams has a stretch-to-stop (at 2000 grams) of 100 percent. Stretch-to-stop may also be referred to as "maximum non-destructive elongation." Unless specified otherwise, stretch-to-stop values are reported herein at a load of 2000 grams. In the elongation or stretch-to-stop test, a 3-inch by 7-inch (7.62 cm by 17.78 cm) sample, with the larger dimension being the machine direction, the cross direction, or any direction in between, is placed in the jaws of a Sintech machine using a gap of 5 cm between the jaws. The sample is then pulled to a stop load of 2000 gms with a crosshead speed of about 20 inches / minute (50.8 cm / minute). For the stretchable laminate material of this invention, it is desirable that it demonstrate a stretch to stop value between about 30-400 percent, alternatively between about 50 and 300 percent, still in a further alternative, between about 80-250 percent. The stretch to stop test is done in the direction of extensibility (stretch). The above procedure can also be used to test average load at 50% elongation. Drape Coefficient Test

[0059] The Cusick drape test can be performed using any suitable drape tester to obtain a drape coefficient. Commercially available drape testers include TF118 tester marked by Testex of Dongguam, China or Model 665 drape tester marketed by James H Heal & Co. of Halifax, England. The drape test can be tested in accordance with ISO Test 9073-9 (2008). TS7 and TS750 Tests

[0060] TS7 and TS750 values were measured using an EMTEC Tissue Softness Analyzer (“TSA”) (Emtec Electronic GmbH, Leipzig, Germany) The TSA comprises a rotor with vertical blades which rotate on the test piece applying a defined contact pressure. Contact between the vertical blades and the test piece creates vibrations, which are sensed by a vibration sensor. The sensor then transmits a signal to a PC for processing and display. The signal is displayed as a frequency spectrum. For measurement of TS7 and TS750 values the blades are pressed against sample with a load of 100 mN and the rotational speed of the blades is 2 revolutions per second. To measure TS7 and TS750 values two different frequency analyses are performed. The first frequency analysis is performed in the range of approximately 200 Hz to 1000 Hz, with the amplitude of the peak occurring at 750 Hz being recorded as the TS750 value. The TS750 value represents the surface smoothness of the sample. A high amplitude peak correlates to a rougher surface. A second frequency analysis is performed in the range from 1 to 10 kHZ, with the amplitude of the peak occurring at 7 kHz being recorded as the TS7 value. The TS7 value represents the softness of sample. A lower amplitude correlates to a softer sample. Both TS750 and TS7 values have the units dB V2rms. Martindale Abrasion

[0061] This test can measure the relative resistance of a sample to abrasion according to Worldwide Strategic Partners (“WSP”) Standard Test No. 20.5 (08). A circular specimen of 165 mm±6.4 mm in diameter with an area of 18,258 sq mm is subjected to a requested number of cycles (10 or 60) with an abradant under a pressure of 9 kilopascals (kPa). The abradant is a 36 inch by 4 inch by 0.05 thick silicone rubber wheel reinforced with fiberglass having a rubber surface hardness 81 A Durometer, Shore A of 81 ±9. The specimen is examined for the presence of surface fuzzing (fiber lofting), pilling (small dumps of fibers), roping, delamination or holes and assigned a numerical rating of 1, 2, 3, 4, or 5 based on comparison to a set of standard photographs similarly numbered, with “1” showing the greatest wear and “5” the least. The test is carried out with a Martindale Wear and Abrasion Tester such as Model No. 103 or 403 from James H. Heal & Company, Ltd. of West Yorkshire, England. Peel Peak Test Procedure:

[0062] This test is intended to determine the “Z” direction peel strength (bond strength) required to separate two nonwoven spunbond layers that have been joined together.

[0063] The peel strength test determines the amount of bonding between component layers of a fabric and is determined by measuring the force required to delaminate the fabric. The force of separation values expressed in gram force are an indication of how well the fabric is bonded. The force of separation that is required to delaminate the component layers of the specimen is tested at an approximate 180° angle over a specified distance.

[0064] Samples are cut to have dimensions of 75 mm in the cross direction and 175 mm in the machine direction. A freeze spray is used to initiate the peel of the layers by spraying the top (50 mm or as needed) of the cut specimen. The bottom portion is covered to prevent overspray. The two layers are peeled apart for a distance of approximately 50 mm along the length of the specimen to give a working area of approximately 100 mm. This method references MTS TestWorks® for Windows software. The test is conducted in conjunction with a tensile tester containing a load cell. The tensile tester, for instance, can be an INSTRON tensile tester. Below is the procedure for carrying out the test.

[0065] 1 . Verify the appropriate load cell is in the tensile tester. For load cell conditioning (warm up), refer to the manufacturer's specifications.

[0066] 2. Ensure the appropriate grips are installed in the tensile tester. Ensure the grips and grip faces are free of build-up and the grip faces are free from dents or other damage.

[0067] 3. Ensure the air pressure to operate the grips is not set beyond the manufacturer's maximum loading specifications.

[0068] 4. T urn on the computer and then follow the software menu selection.

[0069] 5. Follow the instructions for calibrating the load cell for the tensile tester being used.

[0070] 6. Verify the tensile tester parameters meet the following specifications:

[0071] Crosshead Speed 306 ± 10 mm / minute (12 ± 0.4 inch)

[0072] Gage Length 100 ± 1 mm (4 ± 0.04 inch)

[0073] Load Units Grams-force

[0074] Full-Scale Load 10-pound load cell

[0075] Test Result Average load

[0076] Peel Start 100 mm

[0077] Peel End 200 mm

[0078] Test Endpoint 320 mm

[0079] 7. Cut a 175 mm by 75 mm specimen. Specimens should be handled minimally and be free of folds, wrinkles, or creases.

[0080] 8. Place the specimens in the grips.

[0081] 9. Mount the free end of one specimen into one grip and the free end of the other specimen into the other grip such that the bonded junctures of the specimens are centered and there is no slack. Do not clamp the specimens at an angle.

[0082] 10. Start the crosshead.

[0083] 11 . Record the average load in grams-force.

[0084] 12. Remove the specimens. 13. Repeat for the remaining specimens.

[0085] 14. Report the average load to the nearest 0.1 gram-force for each individual test of specimens.

[0086] 15. Calculate the average for all the specimens and report this as the sample value.

[0087] 16. Tensile Tester

[0088] Constant-Rate-of-Extension (CRE) tensile tester with a computer-based data acquisition and frame control system

[0089] 17. Load Cell

[0090] Choose the appropriate type for the tensile tester being used. Use a load cell in which the majority of the peak load results fall between 10 and 90% of the capacity of the load cell. Can use tester from Instron Corporation, Canton, Mass. 02021 , OR MTS Systems Corporation, Eden Prairie, Minn. 55344-2290.

[0091] DETAILED DESCRIPTION

[0092] It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0093] In general, the present disclosure is directed to a nonwoven material having at least two distinct layers. The layers include at least one strength-building layer combined with at least one softness enhancing layer. The strength-building layer, for instance, can be made from a non- elastomeric polymer that has relatively fine fibers. The softness enhancing layer, on the other hand, can be made from one or more elastomeric materials. In accordance with the present disclosure, at least one of the layers contains a layer compatibilizer. The layer compatibilizer is incorporated into at least one of the nonwoven webs in order to improve the bond strength between the two layers.

[0094] In the past, for instance, problems have been experienced in bonding together two dissimilar nonwoven layers, such as a strength layer in combination with a softness layer. These problems can be exacerbated when attempting to produce the multi-layer nonwoven fabrics at high speeds. Although the resulting product has excellent softness characteristics on one side in combination with excellent tensile strength characteristics, the nonwoven fabrics may lack in durability when incorporated into products, such as when used as an outer cover in an absorbent article, such as a diaper, adult incontinence product, feminine hygiene product, or the like.

[0095] Thus, the present disclosure is directed to incorporating a layer compatibilizer into one of the nonwoven webs. In one aspect, the layer compatibilizer can comprise a polymer that reduces the dissimilarity of the two adjoining layers. For instance, the layer compatibilizer can comprise a polymer that is the same type of polymer that is exposed on a surface of the adjoining layer. Two polymers of the same type, for instance, are two polymers in which the primary monomer in each polymer is the same. It was discovered that by incorporating even a small amount of a layer compatibilizer between the two layers can dramatically improve the peel strength of the resulting multi-layer structure. It was also unexpectedly discovered that the layer compatibilizer can also dramatically improve abrasion resistance of the nonwoven material. Thus, the resulting product not only has excellent layer-to- layer integrity in composite strength, but is also highly durable, while still having the characteristics of a soft side in conjunction with high tensile strength.

[0096] In one embodiment, the layer compatibilizer can be added to the polymer or polymer blend that is used to produce the softness enhancing layer. The layer compatibilizer, for instance, can comprise a polymer that is similar to a polymer used to produce the fibers of the strength building layer. For instance, in one aspect, the layer compatibilizer can comprise a polypropylene polymer, such as a polypropylene homopolymer or a polypropylene copolymer.

[0097] Alternatively, the layer compatibilizer can be incorporated into the strength building layer and can comprise a polymer that is similar to a polymer exposed on the surface of the softness enhancing layer. The layer compatibilizer, for instance, can be melt blended with the polymer or blend of polymers used to produce the fibers of the strength building layer or can be applied to the surface of the fibers as a sheath surrounding the polymer or polymer blend that provides the strength building layer with the enhanced strength characteristics. In one aspect, the layer compatibilizer can comprise a polyethylene polymer, such as a polyethylene homopolymer or a polyethylene copolymer. The layer compatibilizer may comprise a non-elastomeric polymer or an elastomeric polymer, such as an elastomeric copolymer.

[0098] The nonwoven material of the present disclosure has numerous uses and applications. In one aspect, for instance, the nonwoven material can be combined or attached to an elastic backing for producing laminates.

[0099] Nonwoven materials made according to the present disclosure offer various advantages and benefits. For instance, the nonwoven materials are relatively strong due to the strength-building layer. In addition, at least one exterior layer of the nonwoven material comprises the softness enhancing layer that is noticeably soft to the touch. Thus, nonwoven materials made according to the present disclosure have a unique balance between strength and softness, while remaining a consolidated and unitary structure.

[0100] The softness enhancing layer, the strength building layer, and the layer compatibilizer are discussed in greater detail below. Softness Enhancing Layer

[0101] As described above, the nonwoven material of the present disclosure generally contains at least one softness enhancing layer and at least one strength-building layer. The softness enhancing layer forms a top or exterior surface of the nonwoven material. The softness enhancing layer is soft to the touch and can be formulated to have a cloth-like feel.

[0102] As will be described in more detail below, at least one polymer used to form the softness enhancing layer typically has a softening temperature that is higher than the temperature imparted during bonding and are extensible or elastomeric. In this manner, the polymers do not substantially soften during bonding to such an extent that the fibers of the softness enhancing layers become completely melt flowable. For instance, polymers may be employed that have a Vicat softening temperature (ASTM D-1525) of from about 100°C to about 300°C, in some embodiments from about 120°C to about 250°C, and in some embodiments, from about 130°C to about 200°C. Exemplary high-softening point polymers for use in forming softness enhancing layers may include, for instance ExxonMobil™ PP3155 (inelastic) and Achieve™ Advanced PP3854 and Dow™ ASPUN 6850.

[0103] Extensible or elastomeric monocomponent and / or multicomponent fibers may be used to form the softness enhancing layers, e.g., facing. Monocomponent fibers are generally formed from a polymer or blend of polymers extruded from a single extruder. Multicomponent fibers are generally formed from two or more polymers (e.g., bicomponent fibers) extruded from separate extruders. The polymers may be arranged in substantially constantly positioned distinct zones across the crosssection of the fibers. The components may be arranged in any desired configuration, such as sheathcore, side-by-side, pie, island-in-the-sea, three island, bull's eye, or various other arrangements known in the art. and so forth. Various methods for forming multicomponent fibers are described in U.S. Pat. Nos. 4,789,592 to Taniguchi et al. and U.S. Pat. No. 5,336,552 to Strack et al., U.S. Pat. No. 5,108,820 to Kaneko, et al., U.S. Pat. No. 4,795,668 to Kruege, et al., U.S. Pat. No. 5,382,400 to Pike, et al., U.S. Pat. No. 5,336,552 to Strack, et al., and U.S. Pat. No. 6,200,669 to Marmon, et al., which are incorporated herein in their entirety by reference thereto for all purposes.

[0104] In some implementations, the polymers of the multicomponent fibers of the softness enhancing layer are spunbond fibers made from thermoplastic materials with different glass transition or melting temperatures where a first component (e.g., sheath) melts at a temperature lower than a second component (e.g., core). Softening or melting of the first polymer component of the multicomponent fiber allows the multicomponent fibers to form a tacky skeletal structure, which upon cooling, stabilizes the fibrous structure. For example, the multicomponent fibers may have from about 20% to about 80%, and in some embodiments, from about 40% to about 60% by weight of the low melting polymer. Further, the multicomponent fibers may have from about 80% to about 20%, and in some embodiments, from about 60% to about 40%, by weight of the high melting polymer. In some implementations, the core of the sheath-core bicomponent fibers include a polypropylene homopolymer or copolymer based on either Ziegler-Natta catalysts or single site catalysts and / or the sheath of the sheath-core bicomponent fibers include homopolymers, copolymers or mixtures thereof from ethylene, propylene, or styrenic derived polymers.

[0105] The basis weight of the softness enhancing layer may generally vary, such as from about 5 grams per square meter (“gsm”) to 200 gsm, in some embodiments from about 6 gsm to about 70 gsm, and in some embodiments, from about 8 gsm to about 35 gsm. In one aspect, the basis weight is less than about 30 gsm, such as less than about 25 gsm, such as less than about 20 gsm, such as less than about 15 gsm, such as less than about 12 gsm, such as less than about 10 gsm, such as less than about 9 gsm, such as less than about 8 gsm, such as less than about 7 gsm, and greater than about 4 gsm. In some embodiments, the nonwoven material of the present disclosure may include multiple softness enhancing layers. The softness enhancing layers, for instance, can be adjacent to one another in the nonwoven material and each softness enhancing layer can have the same basis weight or a different basis weight.

[0106] As described above, in some implementations the nonwoven web is made from monocomponent spunbond fibers. In other implementations the nonwoven web is made from bicomponent spunbond fibers. In these implementations, for example, the bicomponent fiber can contain a polyethylene sheath and a polypropylene based elastomeric core, where the core (but not the sheath) may contain a secondary amide non-blocking additive, which can further improve the garment-like feel of the facing.

[0107] For example, in one aspect, the secondary amide additive is erucamide, oleamide, oleyl palmitamide, ethylene bis-oleamide, stearyl erucamide, or combinations thereof. Of course, it should be understood that, in one aspect, the secondary amide may be a non-fatty acid amide.

[0108] Regardless of the secondary amide selected, in one aspect, the secondary amide is present in the core in an amount of about 0.1 % to about 10% by weight based upon the weight of the core, such as about 0.25% to about 5%, such as about 0.5% to about 2.5%, such as about 0.6% to about 1.5%, such as about 0.7% to about 1 %, or any ranges or values therebetween. Particularly, the present disclosure has found that surprisingly, the secondary amide in the core provides improved spinnability and non-blocking properties to the bicomponent fiber, even when used in small amounts in the core.

[0109] In one aspect, the sheath(s) is / are formed from one or more ethylene or propylene polymers, such as one or more generally non-elastomeric ethylene or propylene polymers. Thus, in one aspect, the non-elastomeric polyolefin may include generally inelastic polymers, such as conventional polyolefins, (e.g., polyethylene), low density polyethylene (LDPE), Ziegler-Natta catalyzed linear low density polyethylene (LLDPE), etc.), ultra low density polyethylene (ULDPE), polypropylene, polybutylene, etc.; polytetrafluoroethylene; polyesters, e.g., polyethylene terephthalate (PET), etc.; polyvinyl acetate; polyvinyl chloride acetate; polyvinyl butyral; acrylic resins, e.g., polyacrylate, polymethylacrylate, polymethylmethacrylate, etc.; polyamides, e.g., nylon; polyvinyl chloride; polyvinylidene chloride; polystyrene; polyvinyl alcohol; polyurethanes; polylactic acid; copolymers and mixtures thereof; and so forth. For instance, the sheath(s) can include an LLDPE available from Dow Chemical Co. of Midland, Mich., such as DOWLEX™ 2517 or DOWLEX™ 2047, or a combination thereof, or Westlake Chemical Corp, of Houston, Tex. Furthermore, in one aspect, the non-blocking polyolefin material may be other suitable ethylene polymers, such as those available from The Dow Chemical Company under the designations ASPUNTM (LLDPE) and ATTANE™ (ULDPE). available from The Dow Chemical Company under the designations DOWLEX™ (LLDPE), ASPUNTM (LLDPE), and ATTANE™ (ULDPE).

[0110] Further, in an aspect, the core is formed from a propylene polymer and / or copolymer. Thus, in one aspect, the core is formed from a propylene-based copolymer plastomers, such as a propylene- based copolymer commercially available under the designations VISTAMAXX™ (e.g., 2330, 6202, and 6102), a propylene-ethylene copolymer-based plastomer from ExxonMobil Chemical Co. of Houston, Texas; FINA™ (e.g., 8573) from Atofina Chemicals of Feluy, Belgium; TAFMER™ available from Mitsui Petrochemical Industries; and VERSIFY™ available from Dow Chemical Co. of Midland, Michigan. In addition to the above, the core can also contain a non-elastomeric olefin polymer, such as a metallocene catalyzed (single site catalyzed) polypropylene polymer in an amount of from about 1 % by weight to about 40% by weight of the core, such as from about 2% by weight to about 5% by weight of the core.

[0111] Regardless of the elastomer(s) and non-elastomeric polyolefin selected, in one aspect the core is present in an amount of about 50% to about 97.5% by weight of the total weight of the elastomeric composition, such as about 60% to about 95%, such as about 70% to about 92.5%, such as about 80% to about 90%, such as about 82.5% to about 87.5% by weight of the total weight of the elastomeric composition, or any ranges or values therebetween.

[0112] Referring to FIGS. 1A and 1 B, respectively, a monocomponent fiber 12 and a bicomponent fiber 14 utilizing a sheath / core arrangement are shown. With respect to bicomponent fiber 14, the core 18 can be formed from a first polymer while the sheath 16 can be formed from a second polymer. Generally, the composition of the monocomponent fiber 12 or the core 18 of the bicomponent fiber can be chosen such that the resulting overall material is elastic, cloth-like, drapable, and soft, and the composition of the sheath 16 of the bicomponent fiber 14 can be chosen such that the sheath 16 provides some blocking properties, while not impacting the garment-like feel of the sheath 16. One such example bicomponent fiber suitable for use herein in the softness enhancing layer is described in U.S. Patent Application Serial Number 63 / 003427, filed on April 1 , 2020, entitled, “Elastic Bicomponent Fiber Having Unique Handfeel,” the entire contents of which are hereby incorporated by referenced including, without limitation, the composition of the claimed elastomeric bicomponent spunbond fiber and resulting nonwoven formed from that fiber.

[0113] FIG. 2 shows an example process for forming elastomeric, monocomponent or bicomponent spunbond fibers. More specifically, the example process in FIG. 2 is configured to form substantially continuous fibers (e.g., to make an extensible or elastomeric layer 30). More particularly, in the case of a bicomponent fiber, different polymer compositions A (e.g., for the sheath) and B (for the core) are initially supplied to a fiber spinning apparatus 21 to form bicomponent fibers 23. Or, in the case of a monocomponent fiber, only one polymer type (e.g., which could include a blended polymer with or without additives) is supplied to a fiber spinning apparatus 21 . Once formed, the fibers 23 are traversed through a fiber draw unit 25 and deposited on a moving forming wire 27. Deposition of the fibers is aided by an under-wire vacuum supplied by a suction box 29 that pulls down the fibers 23 onto the forming wire 27. The forming wire 27 is porous so that vertical air flow created by the suction box 29 can cause the fibers to lie down. In one aspect of the present disclosure, the flow rate of this air flow can be kept relatively low to enhance the tendency of the fibers 23 to remain oriented in the MD direction. Alternatively, the suction box 29 can contain sections that extend in the machine direction to disrupt the vertical air flow with at the point where the fibers are laid onto the moving web, thereby allowing the fibers to have a higher degree of orientation in the machine direction. One example of such a technique is described, for instance, in U.S. Patent No. 6,331 ,268.

[0114] Of course, other techniques may also be employed to help fibers remain oriented in the machine direction. For example, deflector guide plates or other mechanical elements can be employed, such as described in U.S. Patent Nos. 5,366,793 and 7,172,398. The direction of the air stream used to attenuate the fibers as they are formed can also be used to adjust to effect machine direction orientation, such as described in U.S. Patent No. 6,524,521. Apart from process described above, other known techniques may also be employed to form the fibers. In one aspect, for example, the fibers may be quenched after they are formed and then directly deposited onto a forming wire without first being drawn in the manner described above. In such aspects, as described above, the flow rate of this air flow can be kept relatively low to enhance the tendency of the fibers to remain oriented in the MD direction, however, it should be understood that, in one aspect, the fibers are not oriented in primarily the MD direction.

[0115] Referring again to FIG. 2, once the fibers 23 are formed, they may be heated by a diffuser 33, which can blow hot air onto the surface of the fibers to lightly bond them together for further processing. A hot air knife may also be employed as an alternative to the diffuser. Other techniques for providing integrity to the web may also be employed, such heated calender rolls. In any event, the resulting fibers may then be bonded to form a consolidated, coherent nonwoven web structure, for example, to create the elastomeric facing of the present disclosure. Any suitable bonding technique may generally be employed in the present disclosure, such as adhesive or autogenous bonding (e.g., fusion and / or self-adhesion of the fibers without an applied external adhesive). Autogenous bonding, for instance, may be achieved through contact of the fibers while they are semi-molten or tacky, or simply by blending a tackifying resin and / or solvent with polymer composition used to form the fibers. Suitable autogenous bonding techniques may include ultrasonic bonding, thermal bonding, through-air bonding, and so forth. Thermal point bonding, for instance, typically employs a nip formed between two rolls, at least one of which is patterned. Ultrasonic bonding, on the other hand, typically employs a nip formed between a sonic horn and a patterned roll. Although the above describes in detail the use of bicomponent fibers, extensible or elastomeric monocomponent fibers can also be used to create the fibers for the nonwoven web material (e.g., facing).

[0116] The spunbond web may also be subjected to one or more additional post-treatment steps. For example, the spunbond web may be stretched in the cross-machine direction using known techniques, such as tenter frame stretching, groove roll stretching, etc. The spunbond web may also be subjected to other known processing steps, such as aperturing, heat treatments, etc. Strength-building Layer

[0117] As described above, nonwoven materials made in accordance with the present disclosure include at least one softness enhancing layer as described above in combination with at least one strength-building layer. The strength-building layer can be directly attached to the softness enhancing layer.

[0118] The strength-building layer can be formed from continuous filaments or fibers and can also comprise a spunbond nonwoven web. The fibers can be formed from a non-elastomeric polymer, such as a polyolefin. Suitable polyolefins include, but are not limited to, homopolymers, copolymers and terpolymers of ethylene (e.g., low density polyethylene, high density polyethylene, linear low density polyethylene, etc.), propylene (e.g., syndiotactic, atactic, isotactic, etc.), butylene and so forth. In addition, blends and combinations of the foregoing are also suitable for use in connection with the present invention. In one embodiment, for instance, the polymeric portion of the polymer composition will include greater than about 65 weight percent olyolefin polymer(s) and in certain embodiments the polymer may comprise at least about 65, 70, 75, 80, 85, 90, 95% by wt. olefin polymer and / or less than about 100, 99, 98 or 97 wt. % olefin polymer. Further, in a particular embodiment, the polymeric portion of the polymer composition may comprise entirely of olefin polymers such as for example, comprising entirely of polymers selected from the group of propylene, ethylene and butylene polymers. The polymer composition will have a melt-flow rate (MFR) less than about 60 dg / minute, and in certain embodiments will have an MFR greater than about 5, 8, 10, 12 or 15 dg / minute and / or less than about 55, 53, 50, 48 or 45 dg / minute. Further, as is known in the art, the polymer composition may optionally include one or more fillers, colorants (e.g. TiO2, pigments), antioxidants, softening agents, surfactants, slip agents and so forth. In particular, as is well known in the art, one or more slip agents, such as fatty acid amides, may be added to the polymer composition for melt spinning.

[0119] In one aspect, although not necessary, the strength-building layer is formed from non- elastomeric fibers that have a relatively small size. For instance, the fibers can have a denier of less than about 2, such as less than about 1 .5. Referring to FIG. 3, for instance, one embodiment of a process and system 110 for producing strength-building layers is shown.

[0120] In one embodiment, the polymer composition (not shown), typically in the form of pellets, is provided in a hopper 112 and fed into an extruder 114 which melts the polymeric portion of the composition and forms an initial stream of molten polymer. The molten polymer stream is pumped to the spinning assembly 120 via piping 116. While suitable ranges will vary with particular polymers, generally speaking, in order to limit degradation or other undesired effects on the polymers, the molten polymer typically is not heated to a temperature more than about 150°C, 125°C, 100°C or 85°C. of the melting point. In certain embodiments the polymer may be heated to a temperature between about 30°C and about 150°C or between about 45°C and about 125°C above of its melting point.

[0121] The spinning assembly 120 can include various components. For instance, the spinning assembly 120 can include a distributor, a filter or screen, a support plate, and a spinneret that are positioned in the direction of flow within the spinning assembly 120. The molten stream of polymer fed to the distributor, for instance, can spread the molten polymer across a broader area by directing the molten polymer stream laterally and downwardly towards the spinneret. The screen or filter serves to filter impurities or other unwanted debris from the molten streams in order to prevent fouling of the spinneret. Suitable screens may, for example, comprise one or more stacked screens ranging between about 50 to about 350 mesh. In one aspect, the spinneret includes a pattern of conduits extending through the thickness of the spinneret wherein the molten polymer flows through inlet openings and from there through associated inlet channels or counterbores. The molten polymer then enters capillaries that exit through an orifice. Each capillary, for instance, can have the same diameter as the exit orifice. In one embodiment, the portion of the conduit above the capillary (e.g. upstream) can have a significantly larger diameter than that of the capillary. For instance, the portion of the conduit above the capillary can have a diameter that is at least about 250%, such as at least about 350%, such as at least about 450% larger than the capillary diameter.

[0122] The size of the exit orifices and capillary can vary such as for example having a diameter between about 0.2 mm and about 0.45 mm. In certain embodiments, the exit orifice and / or capillary can have a diameter of at least 0.2 mm, 0.23 mm, 0.25 mm, 0.28 mm or 0.29 mm and / or a diameter less than about 0.45 mm, 0.42 mm, and 0.40 mm, 0.39 mm or 0.38 mm. As used herein the diameter, for non-circular orifices, is determined across the longest diameter line of the opening. The length of the capillary (L) extends proportional to the diameter (D) of the exit orifice and the length of the capillary divided by orifice diameter (L / D) will be at least about 4. In certain embodiments, the L / D may be equal to or greater than about 4.0, 4.3, 4.5, 4.7, 5.0, 5.3, 5.5, 5.7, 6.0, 6.3 or 6.5 and / or the L / D may be less than about 10.5, 10.0, 9.7, 9.5, 9.3, 9.0, 8.7, 8.5, 8.3 or 8.0. By way of example, the L / D ratio can be between about 4 and about 10, between about 5 and about 10, between about 6 and about 10, between about 5 and about 9, between about 6 and about 9, or even between about 6 and about 8.

[0123] The pattern of conduits, capillaries, and orifices in the spinneret can vary depending upon the particular application. The spinneret, for instance, can include a series of rows extending in parallel. In certain embodiments the inner or center region of the extrusion area may have less closely spaced exit orifices as compared to regions adjacent the CD edges, proximate the quench air flow. In this regard, the pattern of exit orifices may have a CD extending segment at or proximate the center of the extrusion area that has reduced density of conduits or that is entirely lacking exit orifices. For example, the center region may have a section extending across the CD centerline having an MD width between about 10 and about 60 mm that either lacks any conduits or alternatively that has a significantly reduced capillary density (e.g. a capillary density less than 70%, 60%, 50%, 40% or 30% of the average).

[0124] The spinneret can have a relatively high density or close spacing of exit orifices such as for example those having an exit orifice or hole density at least about 3 exit orifices per cm2; the density being measured in relation to the number of exit orifices within the extrusion area. In certain embodiments the spinneret may have an exit orifice density at least about 3.5, 3.7, 4, 4.3, 4.5, 4.7, 5, 5.3, 5.5, 5.7, 6, 6.5, 6.7, 7, 7.3 or 7.5 exit orifices per cm2and / or no more than about 20, 19.5, 19,

[0125] 18.7. 18.5. 18.3. 18. 17.7. 17.5. 17.3. 17. 16.7. 16.5. 16.3. 16. 15.7. 15.5. 15.3. 15. 14.7. 14.5. 14.3 or 14 exit orifices per cm2. In a further aspect, the number of exit orifices within the spinneret will be greater than 5000 per meter of the extrusion area length (CD length) and in certain embodiments will be greater than about 6000 / M, 6500 / M, 7000 / M, 7500 / M, 8000 / M or even 8500 / M per meter of the extrusion area length (CD length).

[0126] The molten polymer is pumped into and through the spinning assembly and spinneret at high- pressures to achieve the throughputs and exit velocities discussed herein below. The molten polymer is extruded out of the exit orifices at rates of at least about 0.3 g / hole / minute or "g / h / m." To calculate g / h / m, the mass of the extrudate composition pumped through the spinneret over a selected period of time is divided by the number of exit orifices and the selected time. The extrusion rate, in certain embodiments, may be at least about 0.3 g / h / m, 0.33 g / h / m, 0.35 g / h / m, 0.37 g / h / m, 0.4 g / h / m, 0.43 g / h / m or 0.45 g / h / m and / or not more than about 0.6 g / h / m, 0.57 g / h / m, 0.55 g / h / m, 0.53 g / h / m or 0.5 g / h / m. In a further aspect, the molten extrudate is pumped through and out of the spinneret having an exit velocity greater than about 10 feet / minute and in certain embodiments may be at least about 10.3,

[0127] 10.5. 10.7. 11. 11.3. 11.5. 11.7. 12. 12.3 or 12.5 feet / minute and / or may be not more than about 45, 43, 40, 38, 35, 33, 30, 28, 25 or 23 feet / minute. The exit velocity (Ve) of the extrudate at the exit orifices is calculated according to the formula below:

[0128] M the mass flow rate of the extrudate (Ib. / min.)

[0129] E=the number of exit orifices p=density of molten extrudate (Ib. / ft3) A=the cumulative cross-sectional area of the exit orifices (ft2)

[0130] In a further aspect, the temperature of the polymer can be regionally controlled either as it enters the spinning assembly or as it moves through the spinning assembly such that the temperature of the molten polymer extrudate exiting the exit openings proximate the quench air is at a higher temperature relative to the molten polymer extrudate exiting the exit openings within the interior of the spinneret and extrusion region. In reference to the embodiments described herein, molten polymer at a first temperature would be extruded out of the rows of exit openings proximate the CD edge and molten polymer at a second temperature (lower than the first temperature) would be extruded out of rows of exit openings proximate the center of the spinneret and spinning area. In this regard, the quench air will first impact and pass through the outer portions of the bundle and as it does so and cools the molten filaments the quench air will warm prior to striking the inner or centrally located filaments within the bundle. When the outer extruded filaments are at a slightly elevated temperature relative to the inner extruded filaments, this will help improve processing at the conditions described herein and create a more uniform frost line across the total filament bundle.

[0131] As the molten polymer composition is extruded out of the orifices of the spinneret, a bundle of molten strands is formed traveling downwardly and away from the spinneret. Immediately below the lower surface of the spinneret are blowers 140 and 141 which direct cooling or quench air 142 and 143 into the bundle in order to at least partially solidify the molten strands 130.

[0132] Various different quench air systems are known in the art and may be used in connection with the present invention. The quench air may be provided from a single blower at a single temperature or may be provided from multiple blowers at different temperatures. For example, a quench system may include a stack of multiple quench air blowers on one or both sides of the bundle, wherein the upper air boxes provide air at different temperatures relative to that provided by quench air boxes located thereunder. The quench air temperature will vary in relation to the properties of the polymers being melt-spun, the extrusion temperature, quench air speed, the filament speed, filament density, and other factors as is known in the art. Generally speaking, quench air is provided at temperatures between about 5-60°C or about 5-35°C. In addition, the quench air may be provided at speeds between about 30-120 M / minute. Typically the quench air is introduced into the filament bundle at an angle perpendicular to or substantially perpendicular to the direction of the filament flow. However, the quench air may alternatively be directed into the molten filaments at an angle, relative the direction of the filament flow, that is slightly acute or obtuse (i.e. may be directed slightly upwardly or downwardly).

[0133] As may be seen in FIG. 3, the quenched, solidified or substantially solidified filaments 132 are then fed into a filament drawing unit 150 which acts to further attenuate or reduce the diameter of the filaments 130, 132. The filament draw unit 150 has at least two walls 154 defining channels 153,155 through which high speed air pneumatically draws the filaments 132 downwardly away from the spinneret 124 and towards the forming wire 160. The quenched filaments 132 initially enter the constricted intake opening 151 and are directed through an upper narrow channel 153. The constricted opening is typically one having an MD width that is not more than about 25% of the MD width of the extrusion area. In certain embodiments the constricted opening may have an MD width that is not more than about 20%, 18%, 15%, 12% or 10% of the MD width of the extrusion area and / or an MD width that is not less than about 0.5%, 1 %, 2% or 3% of the MD width of the extrusion area. The CD width of the constricted opening may be about the same as the CD length of the extrusion area and in certain embodiments may have a CD length at least about 1 %, 2%, 4% or 5% longer than the CD length of the extrusion area. The quenched filaments and the quench air will together enter the constricted opening.

[0134] Additional high speed air or draw air may also directed into the fiber draw unit such as being directed into the upper narrow channel 153 via conduits and blowers in fluid communication therewith. In addition, the draw air introduced into the channel(s) of the drawing unit may be introduced at speeds greater than about 50 M / second or 75 M / second. The draw air may be directed into the channel(s) from either one or more sides of the draw unit and at one or more locations vertically within the draw unit. The angle of introduction may be either perpendicular to the direction of the filament flow or at a downward angle.

[0135] The fiber draw unit may have additional channels below the initial constricting opening and associated channel. The additional channels below the initial constricted opening and associated channel may be sequentially smaller, wider than the constricted opening or have sections of varying MD width. In reference to the embodiment depicted in FIG. 3, the lower channel 155 is wider than the narrow upper channel 153 associated with the constricted opening 151. The filaments are drawn through the second lower channel 155 and then out of the draw unit 150 through the exit opening 157. In the embodiment shown, the speed of the air rushing downwardly through the draw unit pulls the fibers downwardly away from the spinneret and towards the forming surface. This downward force on the continuous filaments applies a corresponding drawing or pulling force that is transmitted along the quenched filaments and extruded molten filaments. In closed systems, the pressure differential is also a primary driver of the drawing air and filaments. Adequate drawing distance is required in order to sufficiently draw down the fibers. In this regard, the distance between the bottom surface of the spinneret to the convergence of the bundle at a constricted channel opening above the drawing portion is at least about 90 cm and in certain embodiments may be between about 90 cm and about 300 cm or even between about 100 and about 230 cm. In relation to the embodiment shown in FIG. 3, the drawing distance extends from the bottom surface 190 of the spinneret 124 to the inlet opening 151 of the narrow channel 153 atop of the fiber draw unit 150.

[0136] The pneumatic forces acting upon the filaments are configured to achieve a draw ratio of not more than about 1100 and in certain embodiments may be at least about 250, 280, 300, 330, 350, 380, 400, 430, 450, 480, 500, 530, 550, 580, 600, 630 or 650 and / or not more than about 1100, 1080, 1050, 1030, 1000, 980 or 950. The draw ratio is calculated by dividing the terminal velocity (Vr) by the exit velocity (VE discussed above) as follows: Draw Ratio

[0137] The terminal velocity is calculated as follows: where:

[0138] Ve=initial velocity as discussed herein above

[0139] Ae=the cross-sectional area of diameter of the exit orifice

[0140] Ar=the cross-sectional area of the resulting filament

[0141] The entraining air forming the pneumatic forces upon the filaments enters the system from the openings or gaps located between the various components above the drawing unit and the various blowers as noted. However, the filament draw unit will typically employ additional air blowers or other air feeds as is known in the art. The walls 154 of the draw unit 150 may optionally be manipulated inwardly or outwardly in order to modify the size of the channel at different locations within the draw unit. In certain embodiments, the walls 154 may be moved inwardly or outwardly in discrete sections so as to form a channel having varying dimension or widths in order to adjust the drawings forces and spreading of the filaments within the bundle. Still further, in order to improve the uniform spreading and coverage of the formed nonwoven fabric, as is known in the art a deflector plate 156 may be used to spread the filaments. Optionally, electrostatic charge bars (not shown) or other components may further be employed to aid with spreading of filaments, web formation and laydown. While the drawings depict an open air melt-spinning system, it will be readily appreciated that the process of the present invention will also work with closed-air systems as are known in the art. Examples of various quench and drawings systems suitable for use in the present invention include, but are not limited to, those described in U.S. Pat. No. 4,340,563 to Appel et al, U.S. Pat. No. 5,935,512 to Haynes et al., U.S. Pat. No. 6,692,601 Najour et al., U.S. Pat. No. 6,783,722 to Taylor, U.S. Pat. No. 7,037,097 Wilkie et al., U.S. Pat. No. 7,762,800 to Geus et al., U.S. Pat. No. 8,246,898 to Conrad et al., U.S. Pat. No. 8,333,918 to Lennon et al. and US2017 / 0211217 Nitschke et al.

[0142] The fully drawn filaments 134 exit the bottom of the filament drawing unit 150 through the exit opening 157 and are deposited onto a forming surface 160 such as a fabric or wire. As is known in the art, one or more vacuums 162 are positioned beneath the forming surface 160 to draw the filaments on to the forming surface 160 and form a relatively loose matt or web 136 of filaments 134. The vacuums also remove the draw air in order to prevent deflected air from interfering with filament lay-down and / or from disturbing the matt 136 once laid on the wire. The suctioning of the air from underneath the drawing unit can also assist in driving the movement of both the air and fibers through the drawing unit and onto the forming wire.

[0143] Optionally, the matt of filaments can be treated in order to impart some minimal degree of integrity required for additional handling. Such treatment may, for example, include consolidating the matt with a compaction roll (not shown) or through the use of a high velocity through-air bonder 164. Such through-air bonders impart only minimal filament-to-filament bonding sufficient for additional handling and processing and without significantly melting the filaments. Such bonders and methods are described in U.S. Pat. No. 5,707,468 to Arnold et al. In addition, in order to achieve relatively higher basis weight fabrics, multiple banks of spinnerets and drawing units may be located sequential over the foraminous forming surface upstream of the consolidating and / or bonding apparatus.

[0144] After formation, the nonwoven matt is desirably bonded in order to increase the overall integrity and strength of the same. In one aspect, the matt may be mechanically bonded such as by entanglement. In this regard, the filaments may be entangled by hydroentangling which includes subjecting the matt to one or more rows of fine high-pressure jets of water so that the filaments become sufficiently entangled with one another to form a coherent nonwoven fabric. In other embodiments, the matt may be bonded by one or more techniques known in the art such as by the application of adhesive, pressure, heat and / or ultrasonic energy. In certain aspects, the matt may be pattern bonded, as is known in the art, using a pair of bonding rolls 166, 168, wherein at least one of the rolls has a pattern of protuberances or "pins" corresponding to the desired pattern of bond points to be imparted to the matt and form a bonded nonwoven fabric 138. The two cooperative rolls form a nip through which the matt is passed with the application of pressure and, optionally, heat. While suitable bond elements may be formed without the application of heat, use of heat together with pressure is preferred. The bonding can be conducted as is known in the art employing a nip formed by patterned roll and a smooth anvil roll ("pin-to-flat") or by two coordinated patterned rolls ("pin-to-pin"). With respect to the use of a smooth anvil roll, the roll may be a steel roll or alternatively may be coated with a resilient material. By way of example only, various pattern bonding methods are shown and described in U.S. Pat. No. 3,855,046 to Hansen et al., U.S. Pat. No. 4,333,979 to Sciaraffa et al., U.S. Pat. No. 4,374,888 to Bornslaeger, U.S. Pat. No. 5, 110,403 to Ehlert, U.S. Pat. No. 5,858,515 to Stokes et al., U.S. Pat. No. 6,165,298 to Samida et al. and so forth. As is known in the art, the pressures, temperatures, residence time, base sheet composition, basis weight, and other parameters will impact the selection of the desired degree of pressure and / or heat applied to the base sheet to form the bond points. Alternatively, the matt of filaments can be adhesively bonded such by spray, gravure roll or other means for the application of adhesive in the desired pattern as is known in the art.

[0145] The resulting nonwoven fabric desirably has high tensile strength, uniform opacity (coverage) and / or pleasing hand. For many applications the bonded nonwoven fabric can have a basis weight less than about 175 g / m2. In certain embodiments, the nonwoven fabrics can have a basis weight less than about 150 g / m2, 120 g / m2, 90 g / m2, 60 g / m2, 45 g / m2, 35 g / m2, 30 g / m2, 25 g / m2, 20 g / m2, 18 g / m2, 16 g / m2, 14 g / m2, 12 g / m2, 10 g / m2, 9 g / m2, 8 g / m2, 7 g / m2, and further, in certain embodiments, can have a basis weight in excess of about 4 g / m2, 5 g / m2, 7 g / m2or 10 g / m2. Further, the filaments as formed by this process and as provided in the corresponding nonwoven fabric can have an average denier (g / 9000M) of less than about 1.5 or less and in certain embodiments may have an average fiber denier equal to or less than about 1 .4, 1 .3 or 1 .2 and / or at least about 0.7, 0.73, 0.75, 0.77, 0.8, 0.83, 0.85, 0.87 or 0.9. Similarly, the filaments as formed by this process and as provided in the corresponding nonwoven fabric can have an average fiber size less than or equal to about 16 microns and in certain embodiments may have an average fiber size equal to or less than about 16, 15.8, 15.5, 15.3, 15, 14.8 or 14.5 microns and / or at least about 10, 10.3, 10.5, 10.8, 11 , 11.3, 11.5, 11.8 or 12 microns.

[0146] Layer Compatibilizer

[0147] In accordance with the present disclosure, the composite nonwoven fabric contains at least one layer compatibilizer. The layer compatibilizer is present between the softness enhancing layer and the strength building layer for increasing the bond strength between the layers. In one aspect, the layer compatibilizer is incorporated into the fibers used to make the nonwoven webs. For example, the layer compatibilizer can be incorporated into the fibers that are used to form the softness enhancing layer, can be incorporated into the fibers that are used to produce the strength building layer, or can be contained in the fibers of the softness enhancing layer and the fibers of the strength building layer.

[0148] In one embodiment, the layer compatibilizer is incorporated into the softness enhancing layer. For instance, the layer compatibilizer can be incorporated into the fibers of the spunbond web. In one aspect, for example, the strength building layer can comprise spunbond fibers in which a polypropylene polymer is exposed on the surface of the fibers. In this embodiment, the layer compatibilizer can comprise a polypropylene polymer that is incorporated into the fibers of the softness enhancing layer and is present on the surface of the fibers.

[0149] The polypropylene polymer can comprise a polypropylene polymer that is the same as the polypropylene polymer contained in the strength enhancing layer or can comprise a different polypropylene polymer. In one aspect, the layer compatibilizer comprises a non-elastomeric polypropylene polymer. The polypropylene polymer can comprise a syndiotactic polymer, an atactic polymer, an isotactic polymer, or the like. The polypropylene polymer can contain propylene in an amount greater than about 65% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 75% by weight, such as in an amount greater than about 80% by weight, such as in an amount greater than about 85% by weight, such as in an amount greater than about 90% by weight, such as in an amount greater than about 95% by weight, and in an amount of 100% by weight or less, such as less than about 99% by weight, such as less than about 98% by weight, such as less than about 97% by weight. The polypropylene polymer can be a polypropylene homopolymer or a polypropylene copolymer containing propylene in the amounts described above. In one aspect, the non-elastomeric polypropylene polymer can have a melt flow rate of less than about 60 dg / min and greater than about 5 dg / min, such as greater than about 8 dg / min, such as greater than about 10 dg / min, such as greater than about 12 dg / min, such as greater than about 15 dg / min.

[0150] Alternatively, the layer compatibilizer can comprise a polypropylene elastomeric polymer. The polypropylene elastomeric polymer, for instance, can comprise a polypropylene copolymer containing primarily propylene. In one aspect, for instance, the layer compatibilizer can comprise a random copolymer of propylene and ethylene. The polymer can be an isotactic polymer that is optionally metallocene catalyzed. The elastomeric polypropylene polymer can have an ethylene content of greater than about 2% by weight, such as greater than about 5% by weight, such as greater than about 7% by weight, such as greater than about 10% by weight, such as greater than about 12% by weight, and less than about 30% by weight, such as less than about 20% by weight, such as less than about 18% by weight, such as less than about 15% by weight.

[0151] As described above, the softness enhancing layer can comprise bicomponent fibers including a core surrounded by a sheath. The sheath can comprise a non-elastomeric polymer, such as a polyethylene polymer. In accordance with the present disclosure, at least a portion of the sheath can be replaced with the layer compatibilizer. The layer compatibilizer can comprise a polypropylene polymer that can totally replace the polyethylene polymer or can be blended with the polyethylene polymer to form the sheath. For example, the layer compatibilizer can be contained in the sheath in an amount from about 8% by weight to about 100% by weight. For instance, the layer compatibilizer can be contained in the sheath of the fibers of the softness enhancing layer in an amount greater than about 10% by weight, such as in an amount greater than about 12% by weight, such as in an amount greater than about 15% by weight, such as in an amount greater than about 17% by weight, such as in an amount greater than about 20% by weight, such as in an amount greater than about 22% by weight, such as in an amount greater than about 25% by weight, and in an amount less than about 90% by weight, such as in an amount less than about 70% by weight, such as in an amount less than about 50% by weight, such as in an amount less than about 40% by weight, such as in an amount less than about 30% by weight, such as in an amount less than about 25% by weight. The remainder of the sheath can comprise any of the polymers described above with respect to the softness enhancing layer, such as a polyethylene non-elastomeric polymer.

[0152] In an alternative embodiment, the layer compatibilizer can be contained in the strength building layer. For instance, the layer compatibilizer can be combined with the polymers used to form the spunbond fibers, can be present on the surface of the fibers, and can comprise a polymer of the same type that is on the surface of the spunbond fibers of the softness enhancing layer.

[0153] In one embodiment, the softness enhancing layer is comprised of bicomponent fibers in which a polyethylene polymer is exposed on the surface of the fibers. In this embodiment, the layer compatibilizer can also comprise a polyethylene polymer. The polyethylene polymer can be the same polymer that is used to produce the fibers of the softness enhancing layer or can comprise a different polyethylene polymer. The layer compatibilizer, for instance, can comprise a non-elastomeric polyethylene polymer or an elastomeric polyethylene polymer. The polyethylene polymer can comprise a homopolymer or a copolymer. When comprised of a copolymer, the polyethylene polymer can contain ethylene in an amount greater than about 50% by weight, such as in an amount greater than about 55% by weight, such as in an amount greater than about 60% by weight, such as in an amount greater than about 65% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 75% by weight, such as in an amount greater than about 80% by weight, such as in an amount greater than about 85% by weight, such as in an amount greater than about 90% by weight, such as in an amount greater than about 95% by weight. The polyethylene copolymer can contain ethylene in an amount less than about 99% by weight, such as in an amount less than about 98% by weight, such as in an amount less than about 95% by weight, such as in an amount less than about 90% by weight, such as in an amount less than about 88% by weight, such as in an amount less than about 85% by weight. In one aspect, the layer compatibilizer can comprise an ethylene and propylene random copolymer.

[0154] In one aspect, the layer compatibilizer comprises a non-elastomeric polyethylene polymer such as a low density polyethylene, a linear low density polyethylene, an ultra-low density polyethylene, or mixtures thereof.

[0155] The layer compatibilizer can be incorporated into the fibers of the strength building layer using various methods and techniques. In one application, the layer compatibilizer can be melt blended with the polypropylene polymer used to form the fibers. Alternatively, the fibers of the strength building layer can comprise bicomponent fibers as shown in FIG. 1b. The layer compatibilizer can be incorporated into the sheath of the bicomponent fibers. The sheath, for instance, may be made entirely from the layer compatibilizer or may comprise the layer compatibilizer blended with other polymers. The layer compatibilizer can be present in the fibers of the strength building layer in an amount of from about 5% by weight to about 55% by weight. For instance, the layer compatibilizer can be present in the fibers of the strength building layer in an amount greater than about 8% by weight, such as in an amount greater than about 10% by weight, such as in an amount greater than about 12% by weight, such as in an amount greater than about 15% by weight, such as in an amount greater than about 17% by weight, and in an amount less than about 50% by weight, such as in an amount less than about 40% by weight, such as in an amount less than about 35% by weight, such as in an amount less than about 30% by weight, such as in an amount less than about 25% by weight, such as in an amount less than about 23% by weight.

[0156] Multi-layer Nonwoven Material

[0157] In accordance with the present disclosure, at least one strength-building layer is combined with at least one softness enhancing layer in order to produce a multi-purpose nonwoven material. In general, the strength-enhancing layer forms an exterior top surface of the nonwoven material. The strength-building layer, on the other hand, can form the bottom layer or a middle layer of the material. The strength-building layer and the softness enhancing layer can be produced as shown in FIGS. 2 and 3 and then later brought together to form a multi-layer nonwoven web. The two layers can be attached together using any suitable bonding process including thermal bonding, adhesive bonding, ultrasonic bonding, or the like.

[0158] Alternatively, as shown in FIG. 4, a two-bank melt spinning system and process as shown in FIG. 4 can be used to produce the nonwoven material. As shown in FIG. 4, for instance, the process for producing the nonwoven material includes the system 110 for producing strength-building layers and a system 21 for producing softness enhancing layers. The systems include spun bond extruders 110 and 21 that produce fibers 50 that are then deposited onto a forming wire 52. If desired, a vacuum may be utilized to maintain the fibers on the forming wire 52. The spun bond fibers 50 produce a softness enhancing layer on top of a strength-building layer to produce a web 54. The web 54 may be optionally compressed by a compaction roll 56. As shown, a multi-layer nonwoven material 30 is produced that is then wound into a roll 62.

[0159] In the embodiment illustrated in FIG. 4, a two-layer nonwoven material 30 is produced. It should be understood, however, that further extruders can be placed in line for producing nonwoven materials having more than two layers. The additional layers can be further strength building layers, further softness enhancing layers, or other layers as may be desired. For example, the nonwoven material can contain from about 2 to about 10 strength building layers (including all increments of one strength building layer therebetween) and the nonwoven material can contain from about 2 to about 10 softness enhancing layers (including all increments of one softness enhancing layer therebetween). In one aspect, the nonwoven material contains about 3 to about 8 layers including 1 , 2, 3, 4, 5, or 6 strength building layers and the remainder softness enhancing layers. In another aspect, the nonwoven material contains 4 layers including 1, 2, or 3 strength building layers and the remainder softness enhancing layers.

[0160] As described above, the layer compatibilizer of the present disclosure can dramatically improve the bonding strength between the softness enhancing layer and the strength building layer. For instance, the two-layer nonwoven material can display a peel peak load of greater than about 150 gf, such as greater than about 200 gf, such as greater than about 250 gf, such as greater than about 275 gf, such as greater than about 300 gf. The peel peak load can be less than about 5,000 gf, such as less than about 1 ,000 gf. In one embodiment, however, the strength between the layers is so strong that the peel test does not produce a result. For instance, the nonwoven material may tear or rip apart before the two layers delaminate.

[0161] The nonwoven materials made in accordance with the present disclosure can be used in numerous and diverse applications. For example, the nonwoven material can be used in an absorbent article. An absorbent article refers to any article capable of absorbing water or other fluids. Examples of some absorbent articles include, but are not limited to, personal care absorbent articles, such as diapers, training pants, absorbent underpants, incontinence articles, feminine hygiene products, swimwear, baby wipes, and the like; medical absorbent articles such as garments, fenestration materials, underpads, bed pads, bandages, absorbent drapes, and medical wipes; food surface wipers; clothing articles; and so forth.

[0162] The nonwoven material 30 made in accordance with the present disclosure can generally have a basis weight of from about 5 gsm to about 300 gsm, including all increments of 1 gsm therebetween. In one embodiment, the basis weight can be from about 5 gsm to about 170 gsm. Of particular advantage, very lightweight materials can be produced according to the present disclosure that have a significant amount of strength in combination with excellent softness properties. For instance, the above properties can be obtained at basis weights of less than about 30 gsm, such as less than about 25 gsm, such as less than about 20 gsm, such as less than about 18 gsm, and at basis weights of generally greater than about 7 gsm, such as greater than about 9 gsm, such as greater than about 11 gsm, such as greater than about 13 gsm.

[0163] The weight ratio between the strength-building layer(s) and the softness enhancing layer(s) can also vary depending upon the particular application. In one embodiment, the softness enhancing layer can have a greater basis weight than the strength-building layer. Alternatively, the strengthbuilding layer can have a higher basis weight than the softness enhancing layer. In one embodiment, the weight ratio between the strength-building layer and the softness enhancing layer is from about 1 :5 to about 5:1 , such as from about 1 :4 to about 4:1 , such as from about 1 :3 to about 3:1 , such as from about 1 :2 to about 2:1 , such as from about 1 :3 to about 1.5:1 , such as from about 1 :2 to about 1.1 :1. Elastic Laminate

[0164] In one embodiment, the nonwoven material of the present disclosure can optionally be incorporated into an elastic laminate. The nonwoven material, for instance, can be attached to an elastic backing. The elastic backing can be a film or can comprise a plurality of parallel strands, such as filaments or ribbons.

[0165] In some implementations, the elastic film (e.g., film) is formed from one or more elastomeric polymers that are melt-processable, i.e., thermoplastic. Any of a variety of thermoplastic elastomeric polymers may generally be used including, for example, elastomeric polyesters, elastomeric polyurethanes, elastomeric polyamides, elastomeric copolymers, elastomeric polyolefins, and so forth. In some implementations involving aperturing the film, elastomeric semi-crystalline polyolefins are used due to their unique combination of mechanical and elastomeric properties. That is, the mechanical properties of such semi-crystalline polyolefins allows for the formation of films that readily aperture during thermal bonding, but yet retain their elasticity.

[0166] Besides polymers, the elastic film may also contain other components as is known in the art. In one embodiment, for example, the elastic film contains a filler. Other additives may also be incorporated into the film, such as melt stabilizers, processing stabilizers, heat stabilizers, light stabilizers, antioxidants, heat aging stabilizers, whitening agents, antiblocking agents, bonding agents, tackifiers, viscosity modifiers, etc.

[0167] The elastic film may be mono- or multi-layered. Multilayer films may be prepared by coextrusion of the layers, extrusion coating, or by any conventional layering process. Such multilayer films normally contain at least one base layer and at least one skin layer but may contain any number of layers desired.

[0168] The properties of the resulting film may generally vary as desired. For instance, prior to stretching, the film typically has a basis weight of about 100 grams per square meter or less, and in some embodiments, from about 50 to about 75 grams per square meter. Upon stretching, the film typically has a basis weight of about 60 grams per square meter or less, and in some embodiments, from about 15 to about 35 grams per square meter. The stretched film may also have a total thickness of from about 1 to about 100 micrometers, in some embodiments, from about 10 to about 80 micrometers, and in some embodiments, from about 20 to about 60 micrometers.

[0169] Although the backing is described as a film above, it should be understood that the backing can also be in the form of parallel elastic filaments, which includes ribbons.

[0170] Lamination

[0171] In some implementations, laminating the non-woven material to the film involves for example, thermal bonding, adhesive bonding, ultrasonic bonding, pressure bonding, pin aperturing, or some combination thereof.

[0172] In some implementations, to concurrently form apertures and bonds between the film and the nonwoven web material, lamination is generally accomplished through a patterned bonding technique (e.g., thermal point bonding, ultrasonic bonding, etc.) in which the materials are supplied to a nip defined by at least one patterned roll. An example of this concurrent aperturing and bonding is described in U.S. Pat. No. 7,803,244 to Siqueira et al., which is incorporated herein in its entirety by reference thereto for all purposes. Thermal point bonding, for instance, typically employs a nip formed between two rolls, at least one of which is patterned. Ultrasonic bonding, on the other hand, typically employs a nip formed between a sonic horn and a patterned roll.

[0173] In one embodiment, the present disclosure is directed to a nonwoven material comprising a strength building layer comprising spunbond fibers randomly arranged to form a web; the spunbond fibers can have a denier of less than about 2, such as less than about 1 .1 and can be made from a non-elastomeric polymer. The nonwoven material can also have a softness enhancing layer comprising spunbond fibers randomly arranged to form a web; the softness enhancing layer can comprise a top layer of the nonwoven material, wherein the spunbond fibers contained in the softness enhancing layer comprise elastomeric containing fibers.

[0174] In one embodiment, the nonwoven material contains two or more strength building layers. In one embodiment, the nonwoven material contains two or more softness enhancing layers. In one embodiment, the nonwoven material contains two or more softness enhancing layers and two or more strength building layers.

[0175] In any of the above embodiments, the strength building layer(s) can be present in relation to the softness enhancing layer(s) at a weight ratio of from about 1 :4 to about 4:1 , such as from about 1 :3 to about 3:1 , such as from about 1 :3 to about 1.5:1 , such as from about 1 :2 to about 1.1 :1. In one embodiment, any of the embodiments of the nonwoven material described above can be incorporated into an elastomeric laminate. In one embodiment, the laminate comprises an elastic backing attached to the nonwoven material. In one embodiment, the backing comprises an elastic film having a first surface and a second surface. In one embodiment, the nonwoven material is attached to the first surface of the elastic film. In another embodiment, a first nonwoven material is attached to the first surface of the elastic film and a second nonwoven material is attached to the second surface of the elastic film. In one embodiment, the strength building layer of the nonwoven material(s) can be attached to the elastic film and the softness enhancing layer(s) can form an exterior surface of the laminate.

[0176] The present disclosure may be better understood with reference to the following examples.

[0177] Example No. 1

[0178] A nonwoven material containing a layer compatibilizer was produced in accordance with the present disclosure and compared to a similar material not containing the layer compatibilizer. Each sample contained a strength building layer comprised of spunbond fibers attached to a softness enhancing layer also comprised of spunbond fibers. In this example, the strength building layer was formed and unwound. The softness enhancing layer was formed on top of the strength building layer as it was unwound.

[0179] More particularly, the following samples were produced.

[0180] Sample No.1 : Each facing included a strength-building layer and a softness enhancing layer. The strength building layer was a spunbond web made from bicomponent fibers. The core polymer primarily contained a metallocene catalyzed polypropylene homopolymer combined with minor amounts of a VISTAMAXX polypropylene elastomer, a secondary amide, and 0.1 % by weight titanium dioxide particles. The sheath comprised 30% by weight of the fiber and included the same components and the same amounts as the core except the titanium dioxide particles were not present.

[0181] The softness enhancing layer was a spunbond web made from bicomponent fibers containing an elastomeric core surrounded by a sheath. The core contained two elastomeric polymers (a VERSIFY polymer and a VISTAMAXX polymer), a metallocene catalyzed polypropylene, and a secondary amide. In accordance with the present disclosure, a layer compatibilizer was further incorporated into the sheath. In particular, in the past, the sheath was made from a polyethylene polymer. In this example, the entire polyethylene polymer was replaced with the exact same formulation used to produce the sheath of the strength building layer. In particular, the sheath contained a metallocene catalyzed polypropylene polymer in combination with a VISTAMAXX polypropylene elastomer and a secondary amide. The sheath comprised 20% by weight of the spunbond fibers.

[0182] Sample No. 2: Sample No. 2 was similar in construction to Sample No. 1 but did not contain a layer compatibilizer. The bicomponent fibers of the strength building layer contained in the core a metallocene polypropylene polymer combined with 0.1 % by weight titanium dioxide particles. The sheath contained 100% by weight of the metallocene catalyzed polypropylene polymer. The fibers of the softness enhancing layer were exactly the same as the fibers of the softness enhancing layer in Example No. 1 above except the sheath was comprised of 100% by weight of a low density polyethylene polymer.

[0183] A peel test was conducted on the nonwoven material of Example No. 1 . No recorded measurement was capable of being made because the nonwoven material tore and ripped within each layer as opposed to delaminating where the two layers were bonded together.

[0184] The specimens of Sample No. 1 and Sample No. 2 were also subjected to a Martindale Abrasion Test. FIG. 5 illustrates the results of the test for specimens made according to Sample No. 1. FIG. 6 illustrates the results of the test on specimens made according to Sample No. 2. The Martindale Abrasion Test was conducted on the softness enhancing layer.

[0185] As shown in FIG. 5, the specimens according to Sample No. 1 achieved a numerical rating of 5 while the specimens of Sample No. 2 as shown in FIG. 6 received a numerical rating of 1 or 2. As shown in the figures, the result is dramatic and unexpected.

[0186] Example No. 2

[0187] In Example No. 1, the layer compatibilizer was incorporated into the softness enhancing layer. In this example, a layer compatibilizer was incorporated into the strength building layer. In this example, the two nonwoven layers were formed simultaneously and combined.

[0188] The following sample was constructed.

[0189] Sample No. 3: The nonwoven material contained a strength building layer attached to a softness enhancing layer. The strength building layer was comprised of spunbond fibers formed from a metallocene catalyzed polypropylene polymer. The softness enhancing layer was comprised of bicomponent spunbond fibers containing an elastomeric core surrounded by a sheath. The core had the same construction as the core described in Sample No. 1 containing two elastomeric polymers, a metallocene catalyzed polypropylene, and a secondary amide. The sheath was comprised of a low density polyethylene polymer combined with a layer compatibilizer. The layer compatibilizer comprised a metallocene catalyzed polypropylene polymer. The metallocene catalyzed polypropylene polymer was contained in the sheath in an amount of about 20% by weight. The sheath comprised about 20% by weight of the fiber.

[0190] Sample No. 3 above was subjected to the peel test. The nonwoven material displayed a peel peak load of about 300 gf. A similar nonwoven material was also tested that did not contain a layer compatibilizer. This material displayed a peel peak load of only 100 gf.

[0191] These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only and is not intended to limit the invention so further described in such appended claims.

Claims

WHAT IS CLAIMED:1 . A nonwoven material comprising: a strength building layer comprising spunbond fibers randomly arranged to form a web, the spunbond fibers being made from a non-elastomeric polymer; and a softness enhancing layer comprising spunbond fibers randomly arranged to form a web, the softness enhancing layer comprising a top layer of the nonwoven material, the spunbond fibers contained in the softness enhancing layer comprising elastomeric containing fibers; a layer compatibilizer contained in the spunbond fibers of the strength building layer or contained in the spunbond fibers of the softness enhancing layer.

2. A nonwoven material as defined in claim 1 , wherein the layer compatibilizer increases the peel strength between the strength building layer and the softness enhancing layer.

3. A nonwoven material as defined in any of the preceding claims, wherein the layer compatibilizer increases the abrasion resistance of the nonwoven material of a surface of the softness enhancing layer.

4. A nonwoven material as defined in any of the preceding claims, wherein the layer compatibilizer comprises a polymer of the same type that is exposed on a surface of the adjoining layer.

5. A nonwoven material as defined in any of the preceding claims, wherein the spunbond fibers contained in the strength building layer are comprised of a polypropylene polymer, and wherein the spunbond fibers contained in the softness enhancing layer comprise elastomeric containing bicomponent fibers, the bicomponent fibers including a core surrounded by a sheath.

6. A nonwoven material as defined in claim 5, wherein the sheath of the elastomeric containing bicomponent fibers comprises a polyethylene polymer and wherein the layer compatibilizer comprises a polyethylene polymer contained in the spunbond fibers of the strength building layer.

7. A nonwoven material as defined in claim 6, wherein the spunbond fibers of the strength building layer comprise bicomponent fibers, the bicomponent fibers comprising a core containing a polypropylene polymer surrounded by a sheath comprising the layer compatibilizer.

8. A nonwoven material as defined in claim 6 or 7, wherein the layer compatibilizer comprises a polyethylene homopolymer or a polyethylene copolymer containing greater than 80% by weight ethylene.

9. A nonwoven material as defined in claim 6, 7, or 8, wherein the layer compatibilizer comprises a linear low density polyethylene polymer.

10. A nonwoven material as defined in claim 6, 7, 8, or 9, wherein the layer compatibilizer is contained within the spunbond fibers of the strength building layer in an amount from about 5% to about 55% by weight, such as in an amount from about 10% to about 50% by weight, such as in an amount from about 20% to about 40% by weight.

11. A nonwoven material as defined in claim 5, wherein the layer compatibilizer is contained in the sheath of the spunbond fibers of the softness enhancing layer, the layer compatibilizer comprising a polypropylene polymer.

12. A nonwoven material as defined in claim 11 , wherein the layer compatibilizer comprises a polypropylene homopolymer or a polypropylene copolymer.

13. A nonwoven material as defined in claim 11 , wherein the layer compatibilizer comprises a polypropylene homopolymer or a copolymer of polypropylene containing at least 80% by weight propylene.

14. A nonwoven material as defined in any of claims 11-13, wherein the layer compatibilizer is contained in the sheath of the bicomponent fibers in an amount from about 8% by weight to about 100% by weight, such as from about 10% by weight to about 50% by weight, such as from about 10% by weight to about 30% by weight.

15. A nonwoven material as defined in any of claims 11-14, wherein the sheath of the spunbond fibers of the softness enhancing layer further comprises a non-elastomeric polymer combined with the layer compatibilizer.

16. A nonwoven material as defined in claim 15, wherein the non-elastomeric polymer comprises a polyethylene polymer.

17. A nonwoven material as defined in any of the preceding claims, wherein the nonwoven material displays a peel peak load of greater than about 150 gf, such as greater than about 200 gf, such as greater than about 250 gf, such as greater than about 275 gf, such as greater than about 300 gf.

18. A nonwoven material as defined in claim 5, wherein the core of the elastomeric containing bicomponent fibers comprises a polypropylene-based elastomer and a secondary amide.

19. A nonwoven material as defined in claim 18, wherein the polypropylene-based elastomer comprises an ethylene comonomer, a-olefin comonomer, or a combination thereof.

20. A nonwoven material as defined in claim 18 or 19, wherein the secondary amide is a fatty acid amide.21 . A nonwoven material as defined in any of claims 18, 19 or 20, wherein the secondary amide comprises a structure having one of the following:wherein,R14, R15, R16, and Rie are independently selected from C7-C27 alkyl groups and C7-C27 alkenyl groups; andR17 is selected from C8-C28 alkyl groups and C8-C28 alkenyl groups.

22. A nonwoven material as defined in any of claims 18 through 21 , wherein the core contains a second elastomer.

23. A nonwoven material as defined in any of the preceding claims, wherein the nonwoven material has a basis weight of from about 5 gsm to about 170 gsm.

24. A nonwoven material as defined in any of the preceding claims, wherein the strength building layer is present in relation to the softness enhancing layer at a weight ratio of from about 1 :4 to about 4:1 , such as from about 1 :3 to about 3:1 , such as from about 1 :3 to about 1.5:1 , such as from about 1 :2 to about 1.1 :1.

25. An elastomeric laminate comprising a nonwoven material as defined in any of the preceding claims.

26. An elastomeric laminate as defined in claim 25, wherein the laminate comprises a backing attached to the nonwoven material, the backing comprising an elastic film or elastic strands having a first surface and a second surface and wherein the strength building layer is attached to the first surface of the backing.

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