JP2005516677A - Nonwoven webs containing superabsorbent areas and articles containing the same - Google Patents

Abstract

In a nonwoven web containing synthetic polymer fibers, a first surface, a second surface opposite the first surface, a first zone containing a superabsorbent polymer, and from the first surface toward the second surface. An absorbent article comprising: a first region extending; a second region essentially free of superabsorbent polymer; and a second region extending into the nonwoven web from the second surface toward the first surface.

Description

  This application is a continuation-in-part of US patent application Ser. No. 10 / 066,935, filed Feb. 4, 2002.

  The present invention relates to a nonwoven web having a superabsorbent region.

  Absorbent articles, such as disposable diapers and feminine hygiene products, are topsheets, acquisition layers, chemical binders or “fluffs” or “pulps” held together by physical entanglement and compression. Often referred to as a multi-layer comprising a core of compressed cellulose fibers, often referred to as a backsheet. These individual elements are combined during manufacture to produce the final product.

  The topsheet and acquisition layer are discrete elements that function to disperse the liquid, can transport the liquid to a large area of the core, and help maintain a dry feel on the wearer's skin. The topsheet and acquisition layer are separate elements of the absorbent article and are composed of a material different from the material of the absorbent core and tend to have little or no absorbent capacity.

  The absorbent core is designed to absorb and retain liquid. Many efforts have been made to improve the absorption capacity and absorption rate of cellulose fiber cores. Superabsorbent polymers in particulate and powder form have been added to disposable diapers and female napkin cores to improve the absorbent capacity and absorption rate of the articles. For example, in the case of a diaper configuration, superabsorbent powder or particles move with the absorbent core material during the manufacturing process of the diaper. Many problems are associated with superabsorbent powders. Superabsorbent particles are very fine and tend to airborne during processing. Superabsorbent particles generally do not adhere to the substrate and are likely to move and migrate during manufacture, transportation, handling, use, or combinations thereof. The migration of superabsorbent particles can result in insufficient liquid storage capacity in some areas and excessive liquid storage capacity in other areas of the article.

  Cellulose fiber cores have the disadvantage of poor integrity under both dry and wet conditions. Additional compression and embossing processes designed to improve the integrity of the cellulosic fiber core often result in a hard core with poor absorption rate. In addition, loose fibers can float in the air during the manufacture of the cellulosic fiber core, creating a safety issue.

  Airlaid or pre-made absorbent cores provide a thin core product and reduce at least some of the problems associated with processing loose cellulose fibers, but are prone to lack of integrity. Chemical binders are often used to improve the integrity of airlaid cores. However, chemical binders tend to adversely affect the core's absorption rate and capacity.

Summary of the Invention

  In one aspect, the present invention provides a synthetic polymer fiber, a first surface, a second surface opposite the first surface, a first zone comprising a superabsorbent polymer, a nonwoven from the first surface toward the second surface. Non-woven comprising a first zone extending into the web, a second zone essentially free of superabsorbent polymer, and a second zone extending into the nonwoven web from the second surface toward the first surface. Features an absorbent article that includes a web.

  In one aspect, the second zone is a nonwoven web thickness that is sufficiently away from contact with the superabsorbent polymer of the first zone after contact of the superabsorbent polymer with the liquid to prevent the wearer of the article. It extends in.

  In some embodiments, the first zone is impregnated with a superabsorbent polymer.

  In other aspects, the second zone exhibits characteristics including fluid capture, fluid dispersion, or combinations thereof. In some embodiments, the second area is available for contact with the wearer of the absorbent article.

  In other aspects, the first zone can hold fluid.

  In some embodiments, the second zone includes a first plurality of fibers of a first polymer and a second plurality of fibers of a second polymer.

  In other embodiments, the second area is soft to the touch.

  In another aspect, the absorbent article includes a topsheet and a backsheet, and the nonwoven web is disposed between the topsheet and the backsheet. In one embodiment, the backsheet is placed away from the wearer's skin.

  In some embodiments, the backsheet is liquid impervious.

  In other embodiments, the backsheet is moisture vapor permeable.

  In other embodiments, the first zone is coextensive with the second zone.

  In one aspect, the article does not have a fluid capture sheet or a fluid dispersion sheet.

  In one embodiment, a disposable diaper, feminine hygiene product, bandage, wound dressing, surgical pad, adult incontinence pad, breast pad, bib or mattress pad comprising an absorbent article described herein.

  In one aspect, the absorbent article comprises an absorbent core comprising a nonwoven web of synthetic polymer fibers, a first surface, a second surface opposite the first surface, a first zone comprising a superabsorbent polymer, the superstructure The absorbent polymer is formed in situ, the first zone extends into the nonwoven web from the first surface toward the second surface, and is essentially a superabsorbent polymer. A second region that does not include a second region that extends into the nonwoven web from the second surface toward the first surface.

  In another aspect, the invention features an absorbent core having dimensions for use in an absorbent article, the core comprising a nonwoven web comprising synthetic polymer fibers, and superabsorbent formed in situ within the area. A liquid storage area comprising a conductive polymer, the liquid storage area extending from the first surface of the nonwoven web toward the second surface of the nonwoven web, and the liquid capture area is a superabsorbent weight. It includes a liquid capture area that does not include coalescence and extends into the nonwoven web from the first surface of the nonwoven web toward the liquid storage area.

  In another aspect, the present invention provides a first surface, a second surface opposite the first surface, a fluid storage area comprising a superabsorbent polymer, the fluid storage area from the second surface of the web to the first surface of the web. The superabsorbent polymer is formed in situ in the fluid storage area, and the fluid trapping area is essentially free of superabsorbent polymer, Features an article that includes a nonwoven web that includes a fluid capture zone that extends into the nonwoven web from a first surface toward a second surface.

  In another aspect, the invention features a method of making an absorbent article, wherein the method impregnates a first section of a nonwoven web with an aqueous composition that includes a superabsorbent polymer precursor and a cross-linking agent. A first zone extends from the first surface of the web in the depth of the web such that the second surface of the web opposite the first surface does not contain a superabsorbent polymer precursor, and the composition is dried. Including that. In one embodiment, drying involves irradiating the composition with microwaves. In other embodiments, drying involves exposing the composition to heat.

  In one aspect, a method of manufacturing an absorbent article includes impregnating a high loft nonwoven web with an aqueous composition comprising a superabsorbent polymer precursor and a crosslinker, and drying the composition. Includes subjecting the composition to microwave irradiation, and the dried absorbent article comprises from 10 wt% to about 90 wt% superabsorbent polymer.

  The invention features a nonwoven web that can be made to provide fluid capture, fluid distribution and fluid storage functions. Nonwoven webs allow the creation of absorbent articles (eg, personal hygiene articles) where a single element provides fluid capture, fluid distribution and fluid storage functions.

  Other features of the invention will be apparent from the following preferred embodiments and from the claims.

Explanation of terms

  In the context of the present invention, these terms have the following significance.

  “Superabsorbent polymer precursor” means a polymer that can function as a superabsorbent polymer by crosslinking.

  “Superabsorbent polymer” means a polymer capable of absorbing water in an amount many times the polymer weight.

Detailed description

  The nonwoven web includes synthetic polymer fibers, a superabsorbent polymer, a first region extending from the first surface of the web into the depth (ie, thickness) of the web, and a superabsorbent polymer. And including a second section extending from the second surface of the web into the depth of the web, the second surface facing the first surface of the web. The first and second sections are preferably continuous across the length and width of the web and extend into the web depth at a distance of less than 100% of the web depth. The first and second areas are also preferably adjacent or substantially adjacent to each other.

  The superabsorbent polymer containing the first zone is referred to herein as the superabsorbent zone. The superabsorbent area is preferably impregnated in the superabsorbent polymer, i.e. the superabsorbent polymer is present in the entire three-dimensional matrix of the web in the superabsorbent area. It can be present on the web of the zone web, in the gap of the zone web, or in a combination thereof.

  The depth at which the superabsorbent zone extends into the web is referred to herein as the thickness of the superabsorbent zone. Preferably, the superabsorbent zone extends into the web at a depth sufficient to provide the desired absorbent capacity and absorption rate as intended by the absorbent article. The superabsorbent area of the web is preferably from about 10% to about 70% superabsorbent polymer, more preferably from about 10% to about 70% superabsorbent polymer, particularly preferably about 30%. % To about 60% by weight of superabsorbent polymer.

  The superabsorbent area of the web exhibits salt absorption under good load, high salt absorption capacity and high water absorption capacity. Preferably the superabsorbent area is at least 10 g 0.9% salt solution / g superabsorbent area, more preferably at least 15 g 0.9% salt solution / g superabsorbent area under a 0.3 g pound per square inch (psi) load. Particularly preferably exhibits a salt absorption capacity under load of at least 20 g 0.9% salt solution / g superabsorbent area. The superabsorbent area is preferably at least 20 g water / g superabsorbent area, more preferably at least 40 g water / g superabsorbent area, particularly preferably at least 70 g water / g superabsorbent area water within a period of 10 minutes. Also shows the absorption capacity.

  The second zone does not include the superabsorbent polymer and can be thick enough to prevent the gel formed when the superabsorbent polymer contacts the liquid from contact with the wearer. The area free of superabsorbent polymer can extend into the web at a depth sufficient to provide a soft feel to the touch. The thickness of the area of the web that does not contain the superabsorbent polymer may be sufficient to provide fluid capture, fluid distribution, or a combination thereof.

The nonwoven web is preferably a high loft nonwoven web, i.e. a nonwoven web having a density not greater than 0.01 gram per cubic centimeter (g / cm < ³ >). The three dimensional structure of a high loft nonwoven web matrix may include passages such as water channels, fluid (water, blood, and urine) moving, such as wicks. When the liquid comes into contact with the superabsorbent polymer, the superabsorbent polymer begins to swell. In some embodiments, the high loft nonwoven web and the fibers of the high loft nonwoven web expand upon contact with the liquid. The three-dimensional properties of the high loft matrix and the expansion of the web can control the presence of liquid in the web, the movement of liquid into the web, and the expansion of the superabsorbent polymer. The expansion of the web allows the nonwoven web to absorb a large amount of liquid relative to the nonwoven web which is relatively dense and essentially two-dimensional.

  The three-dimensional matrix of high loft nonwoven webs also helps to maintain a superabsorbent polymer that has expanded or gelled within the web matrix. Preferably, the superabsorbent polymer gel does not migrate from the high loft matrix and does not migrate or move during use of the absorbent article.

  Nonwoven webs exhibit good dry strength and maintain strength and integrity when wet. The nonwoven web is preferably at least 2000 g / 25.4 mm, more preferably at least 2500 g / 25.4 mm, particularly preferably at least 3000 g / 25.4 mm dry tensile strength and at least 150 g / 25.4 mm, more preferably at least 400 g / 25.4 mm, Particularly preferred is a wet tensile strength of at least 500 g / 25.4 mm.

The nonwoven web is greater than 22 g / m ² , preferably at least 30 g / m ² , more preferably at least 60 g / m ² , more preferably at least at least 1 millimeter (mm) web thickness (ie, caliper). Preference is given to high loft nonwoven webs having a basis weight of 80 g / m ² , particularly preferably at least 100 g / m ² . High loft nonwoven webs can vary in thickness depending on the application. Suitable high loft nonwoven webs have a thickness of at least 10 mm, more preferably at least 15 mm. High loft nonwoven webs, 0.01g / cm ^3, preferably about 0.002 g / cm ³ ~ about 0.009 g / cm ^3, more preferably from about 0.007 g / cm ³ ~ about 0.009 g / cm ³ It also has a density of Other useful nonwoven web not greater than 0.025 g / cm ^3, and has a no greater density than 0.023 g / cm ^3.

  Nonwoven webs include, for example, polyesters, polyolefins (eg, polypropylene, polyethylene, and copolymers of polyolefins and polyesters), polyamides, polyurethanes, polyacrylonitrile, and combinations thereof, including bicomponents (eg, sheath cores). Includes synthetic polymer fibers of fibers and combinations thereof. Nonwoven webs may also include areas containing fibers of different polymers, polymer groups or polymer combinations that differ with respect to the fiber composition of other areas. The superabsorbent area of the web can include superabsorbent polymer fibers. The nonwoven web is preferably resilient and includes elastic fibers (eg, polyester fibers).

  Nonwoven webs may be formed using a variety of methods, including methods including air laying, wet laying, garnetting and carding, melt blown, melt spinning, and spunbond techniques, combinations thereof. Various bonding systems can be used to bond the fibers of the nonwoven web, including, for example, thermal bonding, resin bonding, mechanical bonding (eg, needle punch and hydroentangling), and combinations thereof.

  The superabsorbent polymer present in the first region of the nonwoven web can absorb water in amounts many times its own weight. Preferably, the superabsorbent polymer can absorb an amount of water at least 100 times its own weight, and can absorb at least 150 times, more preferably at least 200 times its own weight. The superabsorbent polymer present in the superabsorbent zone can be formed in situ, i.e. at the location of the nonwoven web, for example from an aqueous superabsorbent polymer composition.

  The aqueous superabsorbent polymer composition includes a superabsorbent polymer precursor (eg, an alkali-soluble polyelectrolyte) and a crosslinking agent. When the aqueous superabsorbent polymer composition is dried, the superabsorbent polymer precursor is crosslinked to form a superabsorbent polymer. Particularly useful superabsorbent polymer precursors include polymers of water soluble monomers. The polymer is an at least partially neutralized polymer derived from an α, β-ethylenically unsaturated mono- or dicarboxylic acid monomer, an acid anhydride monomer or combination thereof and a crosslinker. Is preferred. Useful water soluble α, β-ethylenically unsaturated mono- or dicarboxylic acid monomers include, for example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid and combinations thereof. is there.

  The expression “partially neutralized” refers to the presence of at least some neutralized carboxylic acid groups in the superabsorbent polymer precursor. The superabsorbent polymer precursor can be completely neutralized. The expression “fully neutralized” means that the superabsorbent polymer precursor composition exhibits a pH greater than 7. The superabsorbent polymer precursor composition is adjusted to a pH of about 5 to about 6 using an alkali metal hydroxide. Examples of alkali metal hydroxides include sodium hydroxide, calcium hydroxide, potassium hydroxide and combinations thereof. As an example, a metal alkoxide can be used instead of a metal hydroxide containing calcium hydroxide and potassium hydroxide. First, about 50% to about 95% of the acid groups, more preferably about 65% to about 85% of the acid groups, and particularly preferably about 75% to about 85% of the acid groups are adjusted to pH 2 with an alkali metal hydroxide. Neutralized to ˜6, then superabsorbent polymer with volatile fugitive alkaline component (ie base) greater than 7, more preferably greater than 7-10, particularly preferably greater than 7-8 It is preferred to further neutralize to pH to achieve a superabsorbent polymer precursor that is fully neutralized, i.e., 100% of the acid groups are neutralized.

  Suitable escape alkali components include ammonia, triethylamine, dimethylethylamine, and combinations thereof. Volatile escape alkaline components dissipate when the aqueous composition dries. Base dissipation liberates a sufficient portion of the carboxylate group to the free acid, ie the carboxylic acid form. The carboxylic acid group is then available for reaction with the crosslinker.

  The viscosity of the aqueous superabsorbent polymer composition is preferably from about 50 centipoise (cps) to about 50,000 cps, preferably from about 100 cps to about 30,000 cps, preferably from about 100 cps to about 20, at a solids content of about 23%. 000 cps, preferably about 100 cps to about 10,000 cps, preferably about 100 cps to about 5,000 cps, preferably about 100 cps to about 2500 cps. Preferred aqueous superabsorbent polymer compositions have a viscosity suitable for application using spraying, saturation, and coating techniques.

  The aqueous superabsorbent polymer composition preferably comprises from about 5% to about 65%, preferably from about 10% to about 50%, more preferably from about 20% to about 40% by weight solids.

  Useful aqueous superabsorbent polymer compositions are described, for example, in PCT patent application WO 00/61642 (Anderson et al.) And US Pat. No. 5,693,707 (Cheng et al.), Where insert. Useful commercially available aqueous superabsorbent polymer compositions are described in H.C. B. It is available from the Fuller Company (Vadnais Heights, Minnesota) under the trade name FULATEXPD-8081-H.

  A sufficient amount of crosslinking agent is added to the aqueous superabsorbent polymer composition to achieve a superabsorbent polymer. Preferably, the crosslinker reacts with the superabsorbent polymer precursor functional groups in less than 24 hours during drying at ambient temperature (ie, about 20 ° C.) or higher. Useful crosslinkers include any material that reacts with the hydrophilic groups of the aqueous polymer. Useful crosslinkers include, for example, zirconium ions, ferric aluminum ions, chromic ions, titanium ions, and combinations thereof, and aziridine. Various suitable cross-linking agents are described in US Pat. No. 4,090,013 and are inserted here. One example of a useful commercially available crosslinker is BACOTE 20 ammonium zirconyl carbonate, available from Magnesium Electron Ink (Flemington, New Jersey). Preferably, the composition comprises a crosslinking agent in an amount of from about 2 parts to about 24 parts, more preferably from about 4 parts to about 14 parts, particularly preferably from about 6 parts to about 10 parts, based on the weight of the dry ingredients. .

  The composition can also include a chain transfer agent to alter the molecular weight of the superabsorbent polymer. Suitable chain transfer agents include, for example, sodium hypophosphite, thioglycolic acid, mercaptans such as primary octyl mercaptan, 2-mercaptoethanol, n-dodecyl mercaptan, n-octyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, Iso-octylthioglycolurates, mercaptocarboxylic acids having 2 to 8 carbon atoms, and esters thereof, such as 3-mercaptopropionic acid and 2-mercaptopropionic acid, such as carbon bromo compounds (e.g. tetrabromide) Halogenated hydrocarbons including carbon and bromotrichloromethane) and combinations thereof. The chain transfer agent may be present in the aqueous superabsorbent polymer composition in an amount not greater than 5% by weight, preferably 1% to about 4%, more preferably 1% to about 3%. it can.

  The composition can also include other ingredients including, for example, wetting agents, defoaming agents, plasticizers, binders and combinations thereof.

  The superabsorbent polymer is applied to the high loft web in the form of an aqueous superabsorbent polymer composition that crosslinks upon drying to form a superabsorbent polymer.

  The aqueous superabsorbent polymer composition can be applied using various techniques including, for example, dipping, spraying, printing, coating, and combinations thereof. Preferably, the superabsorbent area of the web is impregnated with a superabsorbent polymer, i.e. the superabsorbent polymer is present throughout the web matrix.

  Aqueous superabsorbent polymer compositions include, for example, air (including circulating air), heat, microwave irradiation (ie irradiation in the frequency range of 300 MHz to 300,000 MHz, such as 915 MHz, 2450 MHz, 5800 MHz and 22,155 MHz). Including), radio frequency irradiation, ultraviolet light irradiation, electron beam irradiation, and combinations thereof (eg, by passing a nonwoven web through a circulating air oven).

  Superabsorbent nonwoven webs are useful for absorbent articles including, for example, disposable absorbent articles, i.e. articles designed to be disposable after use. Useful uses for superabsorbent nonwoven webs include, for example, the core or core element of various absorbent articles, such as disposable diapers, feminine hygiene products (eg sanitary napkins and panty liners), bandages, Wound dressings, surgical pads, incontinence articles (eg adult incontinence pads and incontinence underwear), clothes (eg training pants, pull-on clothes), chest pads, bibs, sweat pads (eg armpits, wrists and heads) , Collar inserts, shoe inserts, and hat inserts (eg, hat bands). Superabsorbent nonwovens can be used in combination with, for example, cellulose fibers and other brittle materials. The superabsorbent nonwoven may be present in the absorbent article in the form of a continuous web, located in a discontinuous area on other elements of the absorbent article, and combinations thereof. The superabsorbent nonwoven web may be located in the article at various locations and locations, eg, randomly or in a pattern (eg, a strip). In one embodiment, the superabsorbent nonwoven is positioned such that the superabsorbent area is in contact with the cellulose fibers. In other embodiments, the article includes a number of superabsorbent webs that are interleaved with respect to the area of cellulose fibers. The superabsorbent nonwoven can also be maintained in or on the article by the adhesive composition.

  Articles incorporating superabsorbent nonwoven webs include, for example, body fluid permeable topsheets, capture sheets, second absorbent layers (eg, second core or fibrous layer), body fluid impermeable backsheets, and their Other elements including combinations may optionally be included.

  The topsheet can be soft, soft and non-irritating to the wearer's skin. The topsheet can be liquid permeable allowing liquid (eg, urine) to penetrate through the thickness. Suitable topsheets can be made from a wide variety of materials including, for example, porous films including woven webs, non-woven webs, films, porous foams, such as perforated films (eg, films of polyethylene, polypropylene or combinations thereof). The topsheet can be hydrophobic to separate the wearer's skin from the fluid contained in the absorbent layer through the topsheet.

  The acquisition layer is preferably capable of dispersing the liquid on the surface of the core.

  The second absorbent layer can include loose fibers, fibers held together with a binder, compressed fibers, and combinations thereof. The fibers of the second absorbent layer are, for example, natural fibers (for example, wood pulp, jute, cotton, silk and wool and combinations thereof), synthetic fibers (for example, nylon, rayon polyester, acrylic, polypropylene, polyethylene, polyvinyl chloride, polyurethane). , And combinations thereof), and various compositions including combinations thereof.

  The backsheet can be located away from the wearer's skin and prevents the liquid contained in the absorbent core from wetting the article in contact with the absorbent article. The backsheet can be liquid permeable and moisture vapor permeable.

  Superabsorbent nonwoven webs are two elements of absorbent articles that include, for example, between a body fluid permeable topsheet and a body fluid impermeable backsheet, between a capture layer and a body fluid impermeable backsheet, and combinations thereof Can be located between. The superabsorbent area of the nonwoven web can also be contacted with cellulose fibers. The superabsorbent nonwoven web can also be positioned in contact with the wearer.

The invention is further illustrated by the following examples. Parts, proportions, percentages and amounts stated in the examples are by weight unless otherwise specified.
Test procedure
The test procedure used in the example is as follows.
Total Water Absorbency
Total water absorbency (g / g) is the weight in grams (g) of fresh water that a gram of a 100 cm ² sample of the composition absorbs in 10 minutes. A 100 cm ² (10 cm × 10 cm) sample of the dry composition is weighed (WD). The sample is then submerged in raw water for 10 minutes. The wet and expanded composition is placed on a pre-weighed metal screen (WS) for 1 minute. Drain excess water present in the sample. Weigh the wet sample and screen (WW).

Total water absorbency (Twa) is given by the following formula:
Twa = [(WW-WS) -WD] / WD
And reported in g absorbed water / g composition.

Total 0.9% Saline Solution Absorbency Under Load
Total 0.9% salt absorption (g / g) is the weight (g) of 0.9% salt that a gram of a 100 cm ² sample of the composition absorbs in 10 minutes. Total 0.9% salt absorption is measured by weighing (WD) a 100 cm ² (10 cm × 10 cm) sample of the dry composition. Place the sample in a container and place a metal mesh screen and brass weight on top of the sample. Both the metal screen and the brass weight have the same size (ie, coextensive) as the sample, and the total weight of the metal mesh screen and brass weight must act on the sample by 0.3 psi. A sufficient amount of 0.9% salt solution is poured into the container to submerge the absorbent sample. After 10 minutes, remove the weight and metal screen. Immediately weigh the absorbent sample (WW).

The total 0.9% salt absorption capacity (AUL) under load is:
0.9% salt AUL = (WW-WD) / WD
And reported in 0.9% salt solution / g composition absorbed.

Dry Tensile Strength
Cut a 4 inch × 1 inch piece of sample composition and wrap a ½ inch piece of masking tape at each 1 inch wide end of the composition piece. The piece of composition is then placed between jaws of an Instron tester (Instron Corp., Canton, Massachusetts) and the tensile strength is measured at a 12 inch / min crosshead speed. The average tensile strength of 5 samples is reported as dry tensile strength in g / in.

Wet Tensile Strength
Cut a 4 inch × 1 inch piece of sample composition and wrap a ½ inch piece of masking tape at each 1 inch wide end of the composition piece. The piece of composition is then immersed in water for 5 minutes, gently tapped to dry out excess water, and immediately tested by placing the sample between Instron tester jaws. Tensile strength is measured at a 12 inch / min crosshead speed. The average tensile strength of 5 samples is reported as g / in as wet tensile strength.

% Superabsorbent Plymer (SAP) Loading
The percent superabsorbent polymer present in the composition is weighed before the treatment with the superabsorbent polymer, the dried composition after the treatment with the superabsorbent polymer, and subtracted to determine the composition. The weight of the superabsorbent polymer in the body is found and measured by dividing the weight of the superabsorbent polymer by the total weight of the composition. Results are reported as% SAP.

Controls 1 and 2
Polyester fiber nonwoven webs having the properties shown in Tables 1 and 2 were mixed with 95 parts FULATEXPD-8081-H aqueous superabsorbent polymer (23% solids) (HB Fuller Company, Vadnais Heights, Minnesota) and 5 parts BACOTE 20 Samples were prepared by saturation with an aqueous superabsorbent polymer composition of ammonium zirconium carbonate (40% activity supplied) (Magnesium Electron Inc., Flemington, New Jersey). The web was dried and weighed to determine the% superabsorbent polymer present in the composition.

Examples 1-4
Polyester fiber nonwoven webs having the properties shown in Table 1 were prepared from 95 parts FULATEXPD-8081-H aqueous superabsorbent polymer (23% solids) and 5 parts BACOTE 20 ammonium zirconium carbonate (40% activity supplied) ( Samples were prepared by saturation with an aqueous superabsorbent polymer composition from Magnesium Electron Inc., Flemington, New Jersey. The web was dried and weighed to determine the% superabsorbent polymer present in the composition.

The samples of Control 1 and Examples 1-4 were tested in the manner described above to determine dry and wet tensile strength. The weight and thickness of the sample were also measured. The results are shown in Table 1.

Examples 5-17
A superabsorbent composition was prepared according to Example 1, but the basis weight and density of the nonwoven web are as shown in Table 2, and the amount of superabsorbent polymer applied to the web is controlled as shown in Table 2. A composition having a superabsorbent polymer was obtained.

Controls 1 and 2 and Examples 5-17 were tested in the manner described above to determine water uptake and 0.9% salt uptake (AUL) under load. The results are shown in Table 2.

ND = example 18 not measured
Polyester fiber high loft nonwoven web, size 10 cm × 10 cm × 1.1 cm, weight 0.86 g, density 0.0078 g / cm ³ (Carpenter Company, Temple, Texas) PD-8081-H aqueous superabsorbent heavy Saturated with coalescence (HB Fuller Company) and dried. The treated web had a superabsorbent polymer loading of 78.6%. The treated web was then contacted with 75 ml of 0.9% salt solution applied at a rate of 7 ml / sec using a variable flow pump manufactured by Manostat, a Division of Barnant Co., Barrington, Illinois. .

  The web absorbed 75 ml of 0.9% salt solution. There were no leaks or overflows. The surface of the web was wet when touched. A superabsorbent polymer gelled on the surface was visible.

Example 19
A polyester fiber high loft nonwoven web, size 10 cm × 10 cm × 1.5 cm, weight 0.96 g, density 0.0064 g / cm ³ (Carpenter Company) was obtained for use in Example 19. The first section of the web was saturated with PD-8081-H aqueous superabsorbent polymer so that the section containing the superabsorbent polymer extended from the first major surface of the web into a portion of the web depth. The superabsorbent polymer was dried. The superabsorbent polymer loading on the treated web was 85.8%. The first major surface and the second zone extending into the depth of the web from the second major surface of the web opposite the first zone did not contain superabsorbent polymer. The treated web was placed between the two glass plates so that the second major surface, ie the area of the web that was free of superabsorbent polymer, contacted the glass plate. The top glass plate had holes. 75 ml of a 0.9% salt solution was applied to the web through the holes at a rate of 7 ml / sec using a variable flow pump manufactured by Manostat, a Division of Barnant Co., Barrington, Illinois.

Example 20
A polyester fiber high loft nonwoven web, size 9.8 cm × 9.5 cm × 2.0 cm, weight 1.66 g, density 0.0089 g / cm ³ (Carpenter Company) was obtained for use in Example 20. The first section of the web was saturated with PD-8081-H aqueous superabsorbent polymer such that the section containing the superabsorbent polymer extended from the first major surface of the web into a portion of the web depth. The superabsorbent polymer was dried. The superabsorbent polymer loading on the treated web was 65.6%. The first major surface and the second zone extending into the depth of the web from the second major surface of the web opposite the first zone did not contain superabsorbent polymer. The treated web was placed between the two glass plates so that the second major surface, ie the area of the web that was free of superabsorbent polymer, contacted the glass plate. The top glass plate had holes. 75 ml of a 0.9% salt solution was applied to the web through the holes at a rate of 7 ml / sec using a variable flow pump manufactured by Monosat (Manostat, a Division of Barnant Co., Barrington, Illinois).

  The webs of Examples 19 and 20 absorbed 75 ml of 0.9% salt solution. There were no leaks or overflows. The second major surface of the web exhibited an overall dry feel except for the areas where the salt solution was introduced into the major surface of the web. The gelled superabsorbent polymer was not visible on the second major surface of the web.

  Other embodiments are within the scope of the claims. Although superabsorbent compositions have been described for disposable component cores, superabsorbent compositions can be used in a variety of absorbent articles including, for example, wipes, towels, face tissue, mops, and agricultural applications (eg, moisture retention). It is also useful for applications. The composition can also be combined with at least one other nonwoven web in a layered configuration.

Claims (15)

Synthetic polymer fibers,
A first surface;
A second surface opposite the first surface;
A first zone containing a superabsorbent polymer, the first zone extending into the nonwoven web from the first surface toward the second surface, wherein the superabsorbent polymer is formed in situ within the first zone. A second region that is essentially free of superabsorbent polymer and extends into the nonwoven web from the second surface toward the first surface;
An absorbent article comprising a nonwoven web comprising: After the superabsorbent polymer is in contact with the liquid, the second zone extends within the thickness of the nonwoven web at a distance sufficient to prevent contact between the superabsorbent polymer in the first zone and the wearer of the article. The absorbent article according to claim 1. The absorbent article according to claim 1, wherein the first zone is impregnated with a superabsorbent polymer. The absorbent article of claim 1, wherein the second zone exhibits properties including fluid capture, fluid distribution and combinations thereof. The absorbent article of claim 1, wherein the synthetic polymer fiber comprises polyester, polyolefin, polyamide, polyurethane, polyacrylonitrile, or a combination thereof. 6. At least one of the first zone and the second zone includes a first plurality of fibers including a first polymer and a second plurality of fibers including a second polymer. Absorbent article as described in 1. The absorbent article according to any one of claims 1 to 5, wherein the second area is soft against contact. The absorbent article according to any one of claims 1 to 5, further comprising cellulose fibers. The absorbent article according to claim 1, wherein the first area has substantially the same extent as the second area. The absorbent article includes a top sheet and a back sheet,
The absorbent article according to any one of claims 1 to 5, wherein the nonwoven web is disposed between the top sheet and the back sheet. The absorbent article according to claim 10, wherein the backsheet is liquid impervious, moisture vapor permeable, or a combination thereof. Disposable diapers, feminine hygiene products, bandages, wound dressings, surgical pads, adult incontinence pads, breast pads, hooks or mattress pads comprising the absorbent article according to any of claims 1-5. A personal hygiene product comprising an absorbent core comprising the article according to claim 1. A first section of a nonwoven web is impregnated with an aqueous composition comprising a superabsorbent polymer precursor and a crosslinker, the first section being from the first surface of the web to the first surface of the web. A method of manufacturing an absorbent article, the method comprising: extending the depth of the web such that the second surface thereof does not include a superabsorbent polymer precursor and drying the composition. The method of claim 14, wherein the drying comprises exposing the composition to microwave irradiation.