Absorbent article

Abstract

The present disclosure provides an article. In an embodiment, the article includes (1) a web of nonwoven meltblown fibers. The fibers have an average fiber diameter from 1 micron to 15 microns. The fibers comprise (A) an ethylene / a-olefin copolymer having (i) a density from 0.920 g / cc to 0.940 g / cc, and (ii) a melt index from 50 g / 10 min to 250 g / 10 min. The fibers include (B) two or more surfactants, each surfactant having an HLB value from 0.5 to 10.0. The article also includes (2) a plurality of superabsorbent polymer particles (SAP) dispersed in the web.

Description

ABSORBENT ARTICLEBACKGROUND

[0001] High liquid absorbency is required in the absorbent core structures for hygiene products such as sanitary goods, hygienic goods (diapers, feminine sanitary products), wiping cloths, water-retaining agents, dehydrating agents, sludge coagulants, disposable towels, thickening agents, condensation-preventing agents, wound care products and release control agents for various chemicals and pharmaceuticals. Fluff pulp and super absorbent polymer (SAP) are known absorbent materials. Absorbent core structures composed of fluff pulp and / or SAPs, enable large amounts of fluids, e.g., water, urine and / or blood to be absorbed by the article during its use. However, fluff pulp can be bulky and thick which limits its use in products such as feminine pads where thin and lightweight construction is preferred. Horizontal liquid diffusion speed is another critical factor that is often achieved through the use of an acquisition distribution layer (ADL) made with (polyethylene terephthalate) PET. As the PET is not compatible with polypropylene or polyethylene, the recyclability of a hygiene product containing PET is limited.

[0002] Thus, a need exists for a liquid absorbent article with good absorbance properties and lacking PET. A need further exists for a liquid absorbent article composed of ethylene-based polymer that is recyclable.SUMMARY

[0003] The present disclosure provides an article. In an embodiment, the article includes (1) a web of nonwoven meltblown fibers. The fibers have an average fiber diameter from 1 micron to 15 microns. The fibers comprise (A) an ethylene / a-olefin copolymer having (i) a density from 0.920 g / cc to 0.940 g / cc, and (ii) a melt index from 50 g / 10 min to 250 g / 10 min. The fibers include (B) two or more surfactants, each surfactant having an HLB value from 0.5 to 10.0. The article also includes (2) a plurality of superabsorbent polymer particles (SAP) dispersed in the web.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] FIG. 1 is a schematic representation of a liquid uptake test.

[0005] FIG. 2 is a schematic representation for the production of the web of nonwoven fiber.DEFINITIONS

[0006] Any reference to the PeriodicTable of Elements is that as published by CRC Press, Inc., 1990- 1991. Reference to a group of elements in this table is by the new notation for numbering groups.

[0007] For purposes of United States patent practice, the contents of any referenced patent, patent application or publication are incorporated by reference in their entirety (or its equivalent US version is so incorporated by reference) especially with respect to the disclosure of definitions (to the extent not inconsistent with any definitions specifically provided in this disclosure) and general knowledge in the art.

[0008] The numerical ranges disclosed herein include all values from, and including, the lower and upper value. For ranges containing explicit values (e.g., a range from 1, or 2, or 3 to 5, or 6, or 7), any subrange between any two explicit values is included (e.g., the range 1-7 above includes subranges 1 to 2; 2 to 6; 5 to 7; 3 to 7; 5 to 6; etc.).

[0009] Unless stated to the contrary, implicit from the context, or customary in the art, all parts and percents are based on weight and all test methods are current as of the filing date of this disclosure.

[0010] The terms "comprising", "including", "having" and their derivatives do not exclude the presence of any additional component or procedure. The term, "consisting essentially of" excludes any other component or procedure, except those essential to operability. The term "consisting of" excludes any component or procedure not specifically stated.

[0011] An "ethylene-based polymer" is a polymer that contains more than 50 mole percent (mol%) polymerized ethylene monomer (based on the total amount of polymerizable monomers) and, optionally, may contain at least one comonomer. Ethylene-based polymer includes ethylene homopolymer, and ethylene copolymer (meaning units derived from ethylene and one or more comonomers). The terms "ethylene-based polymer" and "polyethylene" may be used interchangeably. Nonlimiting examples of ethylene-basedpolymer (polyethylene) include low density polyethylene (LDPE) and linear polyethylene. Nonlimiting examples of linear polyethylene include linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), very low density polyethylene (VLDPE), multicomponent ethylene-based copolymer (EPE), ethylene / a-olefin multi-block copolymers (also known as olefin block copolymer (OBC)), substantially linear, or linear, plastomers / elastomers, and high density polyethylene (HDPE). Generally, polyethylene may be produced in gas-phase, fluidized bed reactors, liquid phase slurry process reactors, or liquid phase solution process reactors, using a heterogeneous catalyst system, such asZiegler-Natta catalyst, a homogeneous catalyst system, comprising Group 4 transition metals and ligand structures such as metallocene, non-metallocene metal-centered, heteroaryl, heterovalent aryloxyether, phosphinimine, and others. Combinations of heterogeneous and / or homogeneous catalysts also may be used in either single reactor or dual reactor configurations.

[0012] High density polyethylene (or "HDPE") is an ethylene homopolymer or an ethylene / a-olefin copolymer with at least one C3-C10 a-olefin comonomer, or C4-C8 a-olefin comonomer and a density from 0.940 g / cc, or 0.945 g / cc, or 0.950 g / cc, 0.953 g / cc to 0.955 g / cc, or 0.960 g / cc, or 0.965 g / cc, or 0.970 g / cc, or 0.975 g / cc, or 0.980 g / cc. The HDPE can be a monomodal copolymer or a multimodal copolymer. A "monomodal ethylene copolymer" is an ethylene / Cs-Cw a-olefin copolymer that has one distinct peak in a gel permeation chromatography (GPC) showing the molecular weight distribution. A "multimodal ethylene copolymer" is an ethylene / C4-Cw a-olefin copolymer that has at least two distinct peaks in a GPC showing the molecular weight distribution. Multimodal includes copolymer having two peaks (bimodal) as well as copolymer having more than two peaks. Nonlimiting examples of HDPE include DOW™ High Density Polyethylene (HDPE) Resins (available from The Dow Chemical Company), CONTINUUM™ Bimodal Polyethylene Resins (available from The Dow Chemical Company), LUPOLEN™ (available from LyondellBasell), as well as HDPE products from Borealis, Ineos, and ExxonMobil.

[0013] "Low density polyethylene" (or "LDPE") may also be referred to as "high pressure ethylene polymer" or "highly branched polyethylene" and consists of ethylene homopolymer, or ethylene / a-olefin copolymer comprising at least one C3-C10 a-olefin that has a density from0.915 g / cc to less than 0.940 g / cc and contains long chain branching with broad MWD. LDPE is typically produced by way of high pressure free radical polymerization (tubular reactor or autoclave with free radical initiator). LDPE resins typically have a density in the range of 0.915 to 0.935 g / cc. Nonlimiting examples of LDPE include MarFlex™ (Chevron Phillips), LUPOLEN™ (LyondellBasell), as well as LDPE products from Dow, Borealis, Ineos, ExxonMobil, and others.

[0014] "Linear low density polyethylene" (or "LLDPE") is a linear ethylene / a-olefin copolymer containing heterogeneous short-chain branching distribution comprising units derived from ethylene and units derived from at least one C3-C10 a-olefin comonomer. LLDPE is characterized by little, if any, long chain branching, in contrast to conventional LDPE. LLDPE has a density from 0.910 g / cc to less than 0.940 g / cc. Nonlimiting examples of LLDPE include TUFLIN™ linear low density polyethylene resins (available from The Dow Chemical Company), DOWLEX™ polyethylene resins (available from the Dow Chemical Company), FINGERPRINT™ polyethylene resins (available from the Dow Chemical Company), and MARLEX™ polyethylene (available from Chevron Phillips).

[0015] A "fiber," as used herein, is an elongated strand of polymeric material in which the length to diameter ratio is greater than 10. A fiber typically has a round, or substantially round, cross section. Other cross-sectional shapes for the fiber include a trilobal shape, or a flat ( / .e., "ribbon" like) shape. A fiber excludes a film which has opposing parallel, or substantially parallel, sides.

[0016] The term "meltblown fibers" refers to fibers formed by extruding a molten thermoplastic material through a plurality of fine, usually circular, die capillaries as molten threads or filaments into converging high velocity, usually hot, gas (e.g., air) streams which attenuate the filaments 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. Meltblown fibers, which may be continuous or discontinuous, typically have an average fiber diameter less than or equal to 15 microns, or from 0.5 microns to 10 microns. Meltblown webs can be bonded by a variety of means including, but not limited to, autogeneous bonding, i.e., self bonding without further treatment, thermo-calendaringprocess, adhesive bonding process, hot air bonding process, needle punch process, hydroentangling process, and combinations thereof.

[0017] The terms "nonwoven," and "nonwoven web," are used herein interchangeably. "Nonwoven" refers to a web having a structure of individual fibers or threads which are randomly interlaid, but not in an identifiable manner as is the case for a knitted fabric.

[0018] An "olefin-based polymer" is a polymer that contains a majority mole percent polymerized olefin monomer (based on total amount of polymerizable monomers), and optionally, may contain at least one comonomer. Nonlimiting examples of olefin-based polymers include ethylene-based polymer and propylene-based polymer.

[0019] The term "polymer" is a macromolecular compound prepared by polymerizing monomers of the same or different type. "Polymer" includes homopolymers, copolymers, terpolymers, interpolymers, and so on. The term "interpolymer" means a polymer prepared by the polymerization of at least two types of monomers or comonomers. It includes, but is not limited to, copolymers (which usually refers to polymers prepared from two different types of monomers or comonomers, terpolymers (which usually refers to polymers prepared from three different types of monomers or comonomers), tetrapolymers (which usually refers to polymers prepared from four different types of monomers or comonomers), and the like.

[0020] A "propylene-based polymer" is a polymer that contains a majority mole percent of polymerized propylene based on the weight of the polymer and, optionally, may comprise at least one comonomer. Propylene-based polymers typically comprise at least 50 mole percent (mol%) units derived from propylene (based on the total amount of polymerizable monomers.

[0021] The term "spunbond" refers to the fabrication of nonwoven fabric including the following steps: (a) extruding molten thermoplastic strands from a plurality of fine capillaries called a spinneret; (b) quenching the strands with a flow of air which is generally cooled in order to hasten the solidification of the molten strands; (c) attenuating the strands by advancing them through the quench zone with a draw tension that can be applied by either pneumatically entraining the strands in an air stream or by winding them around mechanical draw rolls of the type commonly used in the textile fibers industry; (d) collecting the drawn strands into a web on a foraminous surface (e.g., moving screen or porous belt); and (e) bonding the web of loosestrands into a nonwoven fabric. Bonding can be achieved by a variety of means including, but not limited to, thermo-calendaring process, adhesive bonding process, hot air bonding process, needle punch process, hydroentangling process, and combinations thereof. The average fiber diameter for fibers made from a spunbond fabrication process is typically greater than 15 microns.

[0022] "Superabsorbent polymer material", or "superabsorbent polymer" (or "SAP") refer to water-swellable, substantially water insoluble material that is capable of absorbing at least 10 times its weight in an aqueous solution containing 0.9 weight percent sodium chloride. SAP may be in the form of particles, fibers, flakes, cubes, spheres, and combinations thereof. Nonlimiting examples of superabsorbent materials include synthetic hydrogel polymers and natural materials such as polysaccharides and polypeptides. Other suitable superabsorbent materials include hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, and isobutylene maleic anhydride copolymers and mixtures thereof. Superabsorbent polymer material can be surface cross-linked so that the outer surface of the superabsorbent polymer material has a higher crosslink density than the inner part of the superabsorbent polymer material.TEST METHODS

[0023] Average fiber diameter. The average fiber diameter was measured by the Scanning Electron Microscope (SEM). Samples were analyzed directly and placed on a pin stub using double-sided adhesive carbon discs for SEM. Samples surfaces were studied with a Phenom X- Pro desktop SEM operating at an accelerating voltage of 15kV using a backscattered electron detector (BSE) for imaging of the samples. A minimum of 30 different fibers are measured. The average fiber diameter is reported according to average fiber diameter = i dn / n, where dnis the diameter of the nthfiber.

[0024] Density. Density was measured by the displacement (Archimedes) method, ASTM method D792 Method B. A sample was weighed in air (dry weight) and immersed in a fluid (wet weight). Knowing the density of the immersion fluid, the loss in weight of the sample on immersion allows the sample density to be calculated. A sheet of material was molded underper ASTM D4703 per Annex A.l Procedure C (15°C cooling). On removal from the press, 3 (three) coupons (~1.5" x ~0.5" x ~0.125") were cut from the sheet and density is measured. For Method B, the samples were weighed in air and then immersed in the fluid. The fluid (IPA, isopropyl alcohol) is contained in a double walled vessel and the temperature is controlled to 23°C + / - 0.1°C. The samples were allowed to soak in the fluid for 8 minutes to ensure the samples have equilibrated to the bath temperature. The samples were then weighed while still immersed in the fluid. A glass sinker of known dry weight and volume was then weighed while immersed in the fluid. The density of the immersion fluid was calculated from the known and measured values for the glass sinker (this corrects for any small deviations in the fluid density in the allowable temperature range). The density of the samples may then be calculated from the known fluid density and the measured wet and dry sample weights.

[0025] Hydrophile-Lipophile Balance number (or "HLB number" or "HLB value") is used as a measure of the ratio of hydrophilic and lipophilic grounds in a given surfactant or surfactant blend. It is a value between 0 and 60 which functionally defines the affinity of a surfactant for water or oil. Nonionic surfactants in particular typically have an HLB of between 0 and 20. Surfactants having an HLB of greater than 10 have an affinity for water, and surfactants with an HLB of less than 10 have an affinity for oil.

[0026] Melt Index. Melt index (Ml) or 12 (for ethylene-based polymer), was measured in accordance with ASTM D 1238-10, Condition 190°C / 2.16 kg, Method B, and was reported in grams eluted per 10 minutes.

[0027] Melt Flow Rate. Melt flow rate (MFR) (for propylene-based polymer) was measured in accordance with ASTM D 1238-10, Condition 230 °C / 2.16 kg, Method B, and was reported in grams eluted per 10 minutes.

[0028] Molecular Weight Distribution. Gel Permeation Chromatography (GPC) is used to determine polymer molecular weight. The GPC chromatographic system consists of a PolymerChar GPC-IR (Valencia, Spain) high temperature GPC chromatograph equipped with an internal IR5 infra-red detector (IR5). The autosampler oven compartment is set at 160 °C and the column compartment is set at 150 °C. The columns used are 4 Agilent "Mixed A" 30 cm 20- micron linear mixed-bed columns. The chromatographic solvent used is 1,2,4 trichlorobenzeneand contains 200 ppm of butylated hydroxytoluene (BHT). The solvent source is nitrogen sparged. The injection volume used is 200 microliters and the flow rate is 1.0 milliliter / minute.

[0029] Calibration of the GPC column set is performed with at least 20 narrow molecular weight distribution polystyrene standards with molecular weights ranging from 580 to 8,400,000 g / mol and are arranged in 6 "cocktail" mixtures with at least a decade of separation between individual molecular weights. The standards are purchased from Agilent Technologies. The polystyrene standards are prepared at 0.025 grams in 50 milliliters of solvent for molecular weights equal to or greater than 1,000,000 g / mol, and 0.05 grams in 50 milliliters of solvent for molecular weights less than 1,000,000 g / mol. The polystyrene standards are dissolved at 80 °C with gentle agitation for 30 minutes. The polystyrene standard peak molecular weights are converted to ethylene / alpha-olefin interpolymer molecular weights using the following equation (as described in Williams and Ward, J. Polym. Sci., Polym. Let., 6, 621 (1968)).:

[0031] where M is the molecular weight, A has a value of 0.4315 and B is equal to 1.0.

[0032] A fifth order polynomial is used to fit the respective ethylene / alpha-olefin interpolymer-equivalent calibration points. A small adjustment to A (from approximately 0.39 to 0.44) is made to correct for column resolution and band-broadening effects such that NIST standard NBS 1475 is obtained at a molecular weight of 52,000 g / mol.

[0033] The total plate count of the GPC column set is performed with Eicosane (prepared at 0.04 g in 50 milliliters of TCB and dissolved for 20 minutes with gentle agitation). The plate count (Equation 2) and symmetry (Equation 3) are measured on a 200 microliter injection according to the following equations:

[0034] Plate Count = 5.54 (Eq. 2)

[0035] where RV is the retention volume in milliliters, the peak width is in milliliters, the Peak Max is the maximum height of the peak, and half height is one half of the height of the peak maximum.

[0037] where RV is the retention volume in milliliters and the peak width is in milliliters, Peak max is the maximum position of the peak, one tenth height is one tenth of the height of the peak maximum, and where rear peak refers to the peak tail at later retention volumes than the Peak max and where front peak refers to the peak front at earlier retention volumes than the Peak max. The plate count for the chromatographic system should be greater than 22,000 and symmetry should be between 0.98 and 1.22.

[0038] Samples are prepared in a semi-automatic manner with the PolymerChar "Instrument Control" Software, wherein the samples are weight-targeted at 2 mg / ml, and the solvent (contained 200 ppm BHT) is added to a pre nitrogen-sparged septa-capped vial, via the PolymerChar high temperature autosampler. The samples are dissolved for 3 hours at 1609C under "low speed" shaking.

[0039] The calculations of Mn(GPc), MW(GPC), and MZ(GPC) are based on GPC results using the internal IR5 detector (measurement channel) of the PolymerChar GPC-IR chromatograph according to Equations 5a-c, using PolymerChar GPCOne™ software, the baseline-subtracted IR chromatogram at each equally-spaced data collection point i ( / / ?,) and the ethylene / alpha-olefin interpolymer equivalent molecular weight obtained from the narrow standard calibration curve for the point i (MPoiyethyiene,i in g / mol) from Equation 1. Subsequently, a GPC molecular weight distribution (GPC-MWD) plot (wtcpc(lgMW) vs. IgMW plot, where wtGPc(lgMW) is the weight fraction of the interpolymer molecules with a molecular weight of IgMW) can be obtained. Molecular weight is in g / mol and wtcpc(lgMW) follows the Equation 4.

[0040] f wtGPC(1g M W)d IgM W = 1.00 (Eq. 4)

[0041] Number-average molecular weight Mn(GPc), weight-average molecular weight MW(GPO and z-average molecular weight MZ(GPC) can be calculated as the following equations.

[0045] Molecular weight distribution can be expressed as Mw(GPc) / Mn(GPc).

[0046] In order to monitor the deviations over time, a flow rate marker (decane) is introduced into each sample via a micropump controlled with the PolymerChar GPC-IR system. This flow rate marker (FM) is used to linearly correct the pump flow rate (Flowrate(nominal)) for each sample by RV alignment of the respective decane peak within the sample (RV(FM Sample)) to that of the decane peak within the narrow standards calibration (RV(FM Calibrated)). Any changes in the time of the decane marker peak are then assumed to be related to a linear-shift in flow rate (Flowrate(effective)) for the entire run. To facilitate the highest accuracy of a RV measurement of the flow marker peak, a least-squares fitting routine is used to fit the peak of the flow marker concentration chromatogram to a quadratic equation. The first derivative of the quadratic equation is then used to solve for the true peak position. After calibrating the system based on a flow marker peak, the effective flow rate (with respect to the narrow standards calibration) is calculated as Equation 6. Processing of the flow marker peak is done via the PolymerChar GPCOne™ Software. Acceptable flow rate correction is such that the effective flowrate should be within 0.5% of the nominal flowrate.DETAILED DESCRIPTION

[0048] The present disclosure provides an article. In an embodiment, the article includes (1) a web of nonwoven meltblown fibers and (2) a plurality of superabsorbent polymer particles. The fibers have an average fiber diameter from 1 micron to 15 microns. Each fiber comprises (A) an ethylene / a-olefin copolymer having (i) a density from 0.920 g / cc to 0.940 g / cc and (ii) a melt index from 50 g / 10 min to 250 g / 10 min. Each fiber also includes (B) two or more surfactants. Each surfactant has a HLB value from 0.5 to 10.0. The article further includes (2) the plurality of superabsorbent polymer particles. The superabsorbent polymer particles are dispersed within the web of fibers.1. Web

[0049] The article includes (1) the web of nonwoven meltblown fibers. Each fiber is composed of an ethylene / a-olefin copolymer. The ethylene / a-olefin copolymer can be an ethylene / Ca-Cio a-olefin copolymer, or an ethylene / C4-C8 a-olefin copolymer. Theethylene / a-olefin copolymer has a density from 0.920 g / cc to 0.940 g / cc and a melt index (Ml) from 20 g / 10 min to 250 g / 10 min. Nonlimiting examples of suitable ethylene-based polymer include ethylene plastomer / elastomer, high density polyethylene (HDPE), linear low density polyethylene (LLDPE), low density polyethylene (LDPE), ethylene / a-olefin multi-block copolymer, and combinations thereof.

[0050] In an embodiment, the ethylene / a-olefin copolymer is an ethylene / C4-C8 a-olefin copolymer, or an ethylene / hexene copolymer with one, some, or all of the following properties:(i) a density from 0.920 g / cc to 0.940 g / cc, or from 0.925 g / cc to 0.937 g / cc; and / or(ii) an I2 from 20 g / 10 min to 250 g / 10 min, or from 20 g / 10 min to 180 g / 10 min, or from 75 g / 10 min to 200 g / 10 min, or from 90 g / 10 min to 175 g / 10 min, or from 155 g / 10 min to 185 g / 10 min, or from 175 g / 10 min to 185 g / 10 min; and / or(iii) a Mw / Mn from 2.0 to 6.0, or from 2.0 to 5.0, or from 3.5 to 4.5, or 4.2.

[0051] In an embodiment, the fiber includes a blend of two ethylene / Ce-Cs a-olefin copolymers.

[0052] In addition to the ethylene / a-olefin copolymer, each fiber includes at least two surfactants. Each fiber can include two, or three, or four, or five, or more surfactants. Each surfactant has a HLB value from 0.5 to 10.0, or from 2.0 to 7.0, or from 1.0 to 5.0.

[0053] In an embodiment, each fiber includes a first surfactant and a second surfactant. The first surfactant is a non-ionic surfactant that is a first ethoxylated aliphatic alcohol having an HLB value from 2.0 to 6.0, or from 2.0 to less than 5.0, or from 2.0 to 4.0. The second surfactant is a non-ionic surfactant that is a second ethoxylated aliphatic alcohol having an HLB value from 3.0 to 7.0, or from 4.0 to 6.0, or from 4.5 to 6.0, or from 4.5 to 5.0.

[0054] In an embodiment, the first surfactant is a first ethoxylated aliphatic alcohol with a a HLB value from 2.0 to 6.0 and having a formula (1) formula (1)CnH2n+i(OCH2CH2)xOH wherein n is an integer from 24 to 34, or from28 to 32 and x is from 1 to 5.The second surfactant is a second ethoxylated aliphatic alcohol with a HLB value from 3.0 to 7.0 and having a formula (2) formula (2)CmH2m+i(OCH2CH2)yOH wherein m is an integer from 8 to less than 24, or from 10 to 20, and y is from 1 to 6.

[0055] In an embodiment the first surfactant and the second surfactant are introduced, or otherwise melt blended into, the ethylene / a-olefin copolymer by way of a masterbatch. The first surfactant and the second surfactant are homogeneously mixed into a carrier resin to form the masterbatch. The carrier resin for the masterbatch is a second ethylene-based polymer. The second ethylene-based polymer is different than the ethylene / a-olefin copolymer in at least one property of density, and / or melt index.

[0056] In an embodiment, the second ethylene-based polymer is an ethylene / CzrCs a-olefin copolymer having(i) a density from 0.94 g / cc to 0.97 g / cc, or from 0.95 g / cc to 0.96 g / cc; and / or(ii) a melt index (Ml) from 10 g / 10 min to 40 g / 10 min, or from 20 g / 10 min to 40 g / 10 min, or from 25 g / 10 min to 30 g / 10 min.

[0057] Each fiber may further include additional optional components such as one or more additives. Such additives include, but are not limited to, antistatic agents, color enhancers, dyes, lubricants, fillers, pigments, primary antioxidants, secondary antioxidants, processing aids, UV stabilizers, anti-blocks, slip agents, tackifiers, fire retardants, anti-microbial agents, odor reducer agents, anti-fungal agents, and combinations thereof. The additive(s) may be present in the fiber in an amount from 0 wt%, or from 0.1 wt% to 10 wt%, or from 0.1 wt% to 5 wt%, or from 0.1 wt% to 1.0 wt%, based on total weight of the fiber.2. Superabsorbent polymer (SAP)

[0058] The present article also includes (2) a plurality of superabsorbent polymer particles. The SAP particles have an average particle size from 100 microns to 800 microns. A nonlimitingexample of a suitable material for the superabsorbent polymer is Artic Gel 1010 superabsorbent polymer from BASF.

[0059] The article can be produced by melt blowing a plurality of fibers composed of the ethylene / a-olefin copolymer and the two or more surfactants and dosing a plurality of superabsorbent polymer particles in between the plurality of fibers and depositing the web structure onto a conveyer belt. As used herein, the term "dosing superabsorbent polymer material" refers to depositing an amount of the superabsorbent polymer particles onto or within the matrix of the nonwoven such that the superabsorbent polymer material is not agglomerated on or within the nonwoven material. The process produces a hybrid structure, or otherwise a composite structure, with the superabsorbent polymer particles uniformly dispersed in, or otherwise evenly mixed into, the plurality of fibers.

[0060] In an embodiment, the article includes(1) from 90 wt% to 50 wt%, or from 85 wt% to 55 wt % of a web of nonwoven fibers (based on total weight of the nonwoven web and the SAP particles), the fibers having an average fiber diameter from 1 micron to 15 microns, or from 5 microns to 10 microns,(A) each fiber composed of an ethylene / C4-C8 a-olefin copolymer, or an ethylene / hexene copolymer with one, some, or all of the following properties:(i) a density from 0.920 g / cc to 0.940 g / cc, or from 0.925 g / cc to 0.937 g / cc; and / or(ii) an from 20 g / 10 min to 250 g / 10 min, or from 20 g / 10 min to 180 g / 10 min, or from 75 g / 10 min to 200 g / 10 min, or from 90 g / 10 min to 175 g / 10 min, or from 155 g / 10 min to 185 g / 10 min, or from 175 g / 10 min to 185 g / 10 min; and / or(iii) a Mw / Mn from 2.0 to 6.0, or from 2.0 to 5.0, or from 3.5 to 4.5, or 4.2;(Bl) from 500 ppm to 10,000 ppm, or from 1,000 ppm to 5,000 ppm of a first surfactant that is a non-ionic surfactant having an HLB value from 2.0 to 6.0, or from 2.0 to 4.5, or from 2.0 to 4.0 (wherein ppm is based on total weight of the fiber);(B2) from 500 ppm to 10,000 ppm, or from 1,000 ppm to 5,000 ppm of a second surfactant that is a non-ionic surfactant having an HLB value from 3.0 to 7.0, or from 4.0 to 6.5, or from 4.5 to 6.5 (wherein ppm is based on total weight of the fiber) and(C) from 0.1 wt% to 15 wt%, or from 0.1 wt% to 5 wt%, or from 0.1 wt% to 3 wt% of a carrier resin, wherein wt% for (A), (Bl), (B2), and (C) is based on total weight of the fiber, the carrier resin that is a second ethylene / C4-C8 a-olefin copolymer having(i) a density from 0.94 g / cc to 0.97 g / cc, or from 0.95 g / cc to 0.96 g / cc; and / or(ii) a melt index (Ml) from 10 g / 10 min to 40 g / 10 min, or from 20 g / 10 min to 40 g / 10 min, or from 25 g / 10 min to 30 g / 10 min;(2) from 10 wt% to 50 wt%, or from 15 wt% to 45 wt% of a plurality of SAP particles (wherein wt% for (1) and (2) is based on total weight of the nonwoven web and the SAP particles), the SAP particles composed of a sodium acrylate-based polymer and having an average particle size from 100 microns to 800 microns.

[0061] In an embodiment, the article is a diaper, a feminine hygiene article (feminine pad, tampon), an adult incontinency product, a face mask, a wipe, a wound care product (bandage, gauze), and a tissue.

[0062] Bounded by no particular theory, Applicant discovered (i) the rate of absorption and (ii) the absorption capacity of the SAP particles increases as a result of the ethylene / a-olefin copolymer having an average fiber diameter from 1 micron to 15 microns and containing at least two surfactants with HLB value from 0.5 to 10. The first surfactant and the second surfactant each co-crystalize with the ethylene / a-olefin copolymer and therefore have better compatibility with the fiber of the non-woven web. The SAP particles upon swelling have a high ionic strength and absorb water. In addition to the mobility of the water on the ethylene / a- olefin copolymer fibers, a sliding phenomenon between the fibers occurs with the expanding ionic SAP particle over the surface of the wettable polyethylene fiber with the nonionic surface. The small fiber size (1-15 microns) provides fiber flexibility and allows free expansion of the ionic SAP, leading to high aqueous liquid uptake rate. Each fiber has a non-ionic hydrophilic surface due to the two surfactants. This provides quick wetting and allows the aqueous liquid to freely flow between the fibers and being absorbed by the SAP.

[0063] By way of example, and not limitation, examples of the present disclosure will now be described in detail in the following examples.EXAMPLES1. Materials

[0064] Materials for the inventive examples ("IE") and comparative samples ("CS") are listed in Tables 1A and IB below.

[0065] Table 1A

[0066] PE-1 was produced using a catalyst system including a procatalyst, UCAT™ J (commercially available from Univation Technologies, LLC, Houston, TX), and a cocatalyst, triethylaluminum (TEAL), in a gas phase polymerization process. The UCAT™ J catalyst is partially activated by contact at room temperature with an appropriate amount of a 40 percent mineral oil solution of tri-n-hexyl aluminum (TN HA). The combined catalyst slurry mixture was fed through a stirred tank to provide a minimum of 1 hour residence time prior to being fed to the reactor. The polymerization was continuously conducted, after equilibrium is reached, under the conditions, as shown below in Table IB. Polymerization was initiated by continuously feeding the catalyst slurry and cocatalyst (trialkyl aluminum, specifically tri ethyl aluminum or TEAL) into a fluidized bed of polyethylene granules, together with ethylene, hydrogen, and 1- hexene. Inert gases, nitrogen and isopentane, make up the remaining pressure in the reactor. The granular product was continuously removed from the reactor and purged to remove residual hydrocarbons. The granular product was then combined with additives (1000 ppm Zinc Stearate, 200 ppm Irganox 1076) in an extruder and formed into the final resin pellets.

[0067] Table IB - polymerization conditions for PE-1

[0068] PE-2 was prepared in accordance with Example 3 of International Publication No.W02020 / 106797, the contents of which are incorporated by reference herein.2. Preparation of fibers and nonwoven web

[0069] Samples were made using a meltblown line equipped with two meltblown beams as shown in FIG. 2. The two meltblown beams were arranged in such a way that one beam (upper beam 21) was located at a relatively higher position than the other (lower beam 22). Both beams were aligned so that the hot air streams from both beams blow to the same position on the vacuum drum. A SAP shooter 23 located in between the two meltblown beams was used to dose the SAP into the meltblown fibers. Each melt blown beam was equipped with a single screw extruder, a melt pump, and a multi-row meltblowing die designed by Biax-Fiberfilm Corporation. The meltblowing die distributes molten polymer to an array of cylindrical capillaries (0.5 mm hole diameter), each of which was surrounded by an annular attenuating hot air stream. Right after the molten polymer exits the capillaries, the molten polymer was stretched by the attenuating hot air and form continuous thin fibers 210 and 220. The fibers were cooled down and solidified by the quench air. When the SAP shooter was turned on, the SAP particles 230 were fed in and mixed with the solid fibers and uniformly dispersed in between the fibers before the SAP / fiber web was applied on the vacuum drum 24. The vacuum drum rotates and conveys the SAP / fiber web to a winder 25. Subsequently, the SAP / fiber composite web was wound on the winder to form a roll stock. The throughput rate of both upper and lower meltblown beams was set at 0.2 grams / hole / minute. The die-to-collector distance (DCD) was set at 31 cm. The vacuum drum blower was set at 100%. Table 2A and 2B below show the process conditions for producing the sample webs. Two surfactant masterbatches, Techsurf PPM 15560 and Techsurf PM 19668 are used. The surfactant masterbatches were dry blended with the PE-1, PE-2 or PP at certain ratios before fed into the hopper of the single screw extruders.

[0070] Table 2A. Upper beam melt blown line conditions

[0071] Tale 2B. Lower beam melt blown line conditions

[0072] Table 3 shows the materials used in the upper beam and lower beam extruders.

[0073] Table 3

[0074] Samples were cut into 2 inch x 2 inch samples and were cut from the article of SAP / fiber composite for fiber diameter measurement and liquid uptake test. The average fiber diameter of all the samples is from 5 microns to 10 microns. Fibers are continuous and fiber length is greater than 10 cm.

[0075] Table 4A, 4B, and 4C show the liquid uptake results.

[0076] Table 4A -average sample weight (ASW") (grams) per soak time

[0077] Table 4B -average liquid uptake ("ALU") (grams) per soak time

[0078] Table 4C -average liquid update per weight SAP ("ALU / SAP") (grams) per soak time

[0079] Applicant discovered that the nonwoven web of the present ethylene / a-olefin copolymer fibers with average fiber diameter of 1-15 microns with two surfactants and SAP particles exhibits a higher liquid update (ALU) than a nonwoven web of propylene-based fibers and the same SAP particles.

[0080] Bounded by no particular theory, the 1-15 micron diameter fibers composed of the present ethylene / a-olefin copolymer and containing two surfactants provide improved lubricity (i.e., reduced friction) with the SAP particles while simultaneously maintaining a suitable support structure to hold the SAP particles in place within the nonwoven web. This combination of lubricity and support provided by the fibers promotes greater and more rapid liquid uptake capacity by the SAP particles. The improved liquid uptake capacity provides the present article with the same or greater absorbent capacity as conventional articles, yet utilizing less (10-50 wt%) SAP particles.

[0081] Techsurf PPM 15560 masterbatch is not a suitable surfactant masterbatch because the carrier resin is polypropylene. Blending Techsurf PPM 15560 masterbatch with PE-1 and / or PE-2 causes fiber breaks during the meltblown process due to the incompatibility between the polypropylene carrier resin and the ethylene / a-olefin copolymer in the fiber. Applicant discovered Techsurf PM19668 masterbatch contains polyethylene carrier resin with a density (0.94-0.97 g / cc) and an Ml (10-40 g / 10 min) suitable to disperse the first surfactant and the second surfactant uniformly into the fiber and allowing the surfactants to diffuse to the fiber surface.

[0082] It is specifically intended that the present disclosure not be limited to the embodiments and illustrations contained herein, but include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.

Claims

CLAIMS1. An article comprising:(1) a web of nonwoven meltblown fibers, the fibers having an average fiber diameter from 1 micron to 15 microns, the fibers comprising(A) an ethylene / a-olefin copolymer having(i) a density from 0.920 g / cc to 0.940 g / cc,(ii) a melt index from 50 g / 10 min to 250 g / 10 min; and(B) two or more surfactants, each surfactant having an HLB value from 0.5 to 10.0; and(2) a plurality of superabsorbent polymer particles (SAP) dispersed in the web.

2. The article of claim 1 comprising(C) a carrier resin for carrying the two or more surfactants, the carrier resin comprising a second ethylene / a-olefin copolymer having(i) a density from 0.930 g / cc to 0.970 g / cc, and(ii) a melt index from 20 g / 10 min to 50 g / 10 min.

3. The article of any of claims 1-2 wherein each fiber comprises from 500 ppm to 10000 ppm of a first surfactant; and from 500 ppm to 10000 ppm of a second surfactant wherein ppm is based on total weight of the fiber.

4. The article of any of claims 1-3 wherein the first surfactant is a first ethoxylated aliphatic alcohol having a formula (1)CnH2n+i(OCH2CH2)xOH wherein n is an integer from 24 to 34, andx is from 1 to 5.

5. The article of claim 4 wherein the ethoxylated aliphatic alcohol has a HLB value from 2.0 to 6.0.

6. The article of any of claims 1-5 wherein the second surfactant is a second ethoxylated aliphatic alcohol having a formula (2)CmH2m+i(OCH2CH2)yOH wherein m is an integer from 8 to less than 24, and y is from 1 to 6.

7. The article of claim 6 wherein the second ethoxylated aliphatic alcohol has a HLB value from 3.0 to 7.0.

8. The article of any claims 1-7 comprising(1) a web of nonwoven fibers, the fibers having an average fiber diameter from 1 micron to 15 microns, the fibers comprising(A) an ethylene / C4-Cs a-olefin copolymer having(i) a density from 0.920 g / cc to 0.940 g / cc,(ii) a melt index from 50 g / 10 min to 150 g / 10 min,(Bl) from 500 ppm to 10000 ppm of a first surfactant that is a non-ionic surfactant having an HLB value from 2.0 to 6.0;(B2) from 500 ppm to 10000 ppm of a second surfactant that is a non-ionic surfactant having an HLB value from 3.0 to 7.0;(C) from 0.1 wt% to _15_ wt% of a carrier resin, and wt% for (A), (Bl), (B2), and (C) is based on total weight of the fiber; and(2) from 10 wt% to 50 wt% of a plurality of SAP particles uniformly dispersed in the web wherein wt % is based on total weight of (1) and (2).

9. The article of any of claims 1-8 wherein the article is selected from the group consisting of a diaper, a feminine hygiene article, an adult incontinency product, a face mask, a wipe, a wound care product, and a tissue.

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