JP2002517303A - Absorber structure having an integral layer of superabsorbent polymer particles - Google Patents

Abstract

(57) [Problem] To provide a thinner and more comfortable absorbent product. SOLUTION: An absorber structure is formed by bonding a separate layer of the superabsorber to one surface of the absorber structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD OF THE INVENTION

This patent application claims priority under 35 USC §119 from Provisional Application No. 60 / 088,451, filed June 8, 1998, which is incorporated by reference in its entirety. .

The present invention relates to a method of preparing superabsorbent roll products for use in disposable absorbent hygiene articles, such as diapers and sanitary napkins, and to products according to the method. The water-based binder, preferably expanded, is mixed with conventional superabsorbent particles to form a separate but essential superabsorbent layer on the surface of the fibrous absorbent structure. When used in disposable absorbent products, the essential superabsorbent layer is
Disposed distal to expected liquid attack. The attack side of such a disposable absorbent article is preferably provided with a capture layer of bound hardened cellulose or thermoplastic binder fibers or a synthetic fiber combined with a powder, latex binder, or a mixture thereof.

[0003]

[Prior art]

Conventional absorbent articles, such as baby diapers, adult incontinence devices, and feminine napkins, typically have a liquid permeable topsheet that has the function of not blocking the flow of liquid to the absorbent core, Between the absorbent core and a liquid-impermeable backing sheet, usually made of plastics material, which has the function of preventing it from penetrating the absorbent core and soiling the undergarment of the user of the absorbent article. Made of absorbent core based on cellulose fiber fluff.

[0004] The absorbent core of these absorbent articles is typically composed of fiberized wood pulp, with or without superabsorbent polymer particles. The absorbent core is typically mounted on a pad forming unit of a processing machine to facilitate processing.
ier tissue). Some absorbent core forming units have a laminating capability in which a second separate fluff layer is overlaid on the first fluff-based absorbent layer to form a multilayer absorbent structure. In these absorber structures, the first layer can contain superabsorbent polymer particles. Regarding conventionally manufactured absorber structures, US Pat. Nos. 5,009,650, 5,378,528, 5,128,082,
5,607,414, 5,147,343, 5,149,335, 5,5
22,810, 5,041,104, 5,176,668, 5,389,
181 and 4,596,567, the disclosures of which are incorporated herein by reference.

[0005]

[Problems to be solved by the invention]

In recent years, the market demand for thinner and more comfortable absorbent products has increased.
Ultra-thin women's napkins are no longer composed of loose wood pulp, which tends to be bulky products, and are air-laid based on roll products.
id) Consists of an absorbent core, in which case the preformed roll of absorbent core material is unwound directly on the absorbent pad making machine without the fiberizing step required for fluff-based products. Efforts based on roll products result in product thinness that cannot be achieved with loose fluff-based technology.

[0006] With respect to the superabsorbent polymer component of the absorbent structure, those skilled in the art know that the carboxyl polyelectrolyte can be crosslinked to produce a material commonly referred to as a superabsorbent. (Eg, U.S. Pat. Nos. 3,669,103 and 3,670,
No. 731). These materials are used to improve the absorbency of the disposable absorbent product. Superabsorbent polymers can be coated (as continuous and discontinuous coatings) on a variety of materials (see U.S. Pat. No. 4,076,673). As described in U.S. Pat. No. 3,686,024, a layer of superabsorbent particles can be bonded to a fibrous substrate utilizing the inherent viscosity of a water-swellable superabsorbent. Heat activated tacky binders can also be used as described in EP 0641835 A1.
U.S. Pat. No. 5,128,082 discloses that superabsorbent particles are deposited between two fiber layers and a latex diluent is applied to each side of the sandwich structure to stabilize the web and to reduce the particles. The manufacture of bonded superabsorbent-containing webs is taught. U.S. Pat. No. 5,071,681 describes the preparation of an air-laid fibrous web in which a water-insoluble binder is applied to one surface of the web and a superabsorbent-forming water-soluble binder is applied to the other surface. It is disclosed to apply a polymer. In U.S. Pat. No. 4,444,830, a liquid superabsorber precursor solution is chemically foamed and applied to a base fluffy material, and the coated fluffy material is dried and destroyed. Mechanically, a fibrous fluff matrix comprising absorbent polymer platelets dispersed throughout the matrix.

[0007] As described in, for example, US Pat. No. 3,686,024, binding highly water-swollen superabsorbent particles to a fibrous matrix requires the removal of large amounts of water from the absorbent structure prior to use. Must be removed, resulting in processing losses. Thermally bonding the particles to the fibers in the web can be achieved by spreading or mixing with the fibrous substrate and mixing the adhesive with the particles before heating to melt the thermal binder. Requires a processing step. Spraying a diluted solution of the liquid superabsorber precursor onto the airlaid web leads to penetration of the superabsorbent into the web, and the superabsorbent polymer has more individuality than the coating on the fibers of the web. It becomes a low layer. Adding superabsorbent particles to the web between two or more fiber dispersion heads and spraying a latex binder embeds the particles in the web and creates a superabsorbent dispersion layer at the bottom of the airlaid web. Hinder. Those skilled in the art will appreciate that when superabsorbent particles are mixed with fibers, whether bound or not, the superabsorbent and surroundings that prevent the superabsorber from fully exerting its absorption performance It has been recognized that there is competition for liquids between fiber structures. The present invention avoids these limitations by placing the superabsorbent particles in separate but integral layers.

[0008]

[Means for Solving the Problems]

Applicants have now discovered that it is desirable to have a separate layer of superabsorbent bonded to one side of the absorbent structure. It has now been found that the superabsorbent polymer material does not need to be dispersed throughout the absorbent composite in order for the superabsorber to perform its intended performance.
In fact, by focusing the superabsorber in a separate layer furthest from the liquid attack, the fibrous material in the absorber composite is more effectively used to first absorb and then transfer the liquid. Available. In a preferred embodiment of the present invention, the integral layer of superabsorbent particles is applied in a discontinuous manner to facilitate the transfer of liquid from the acquisition / dispersion layer. The method of discontinuity is not limited, for example, by masking the area of the particle dispersion head, or by silk-screen type printing of a latex binder, such that the particles bind only to the area coated with the binder. It can be achieved by any method known to those skilled in the art. Thus, more imperfect fibers are required to achieve performance comparable to certain conventional products.

Accordingly, the present invention is directed to a superabsorbent roll product suitable for use in a disposable absorbent product, comprising a separate superabsorbent structure containing bound superabsorbent polymer particles. The present invention further relates to a method for producing the roll product of the present invention provided with the superabsorbent layer of the present invention.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

All patents, patent applications, and references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present disclosure will control.

The present invention is directed to a superabsorbent roll product suitable for use in a disposable absorbent product having a separate superabsorbent layer containing bound superabsorbent polymer particles.
Typically, the layer of superabsorbent particles is attached to the surface of a fibrous absorbent layer, such as an airlaid nonwoven.

When used in a disposable absorbent product, such as a diaper or feminine hygiene product, the superabsorbent layer of the present invention is bonded to the fibrous absorbent layer and distal to a user of the absorbent product. Is placed on the surface of the product.

The superabsorbent layer of the present invention contains superabsorbent polymer particles and a water-soluble or water-dispersible polymer binder. The superabsorbent layer usually does not contain any additional fibers, but can include those that usually protrude from the surface of the fibrous structure and those that surround the depressions on the surface where the superabsorbent particles fit. “Superabsorbent polymer particles”
The term is intended to include any particle morphology of the superabsorbent polymer, including irregular granules, spherical particles (beads), short fibers and other long particles. The term "superabsorbent polymer" refers to a normally water-soluble polymer that has been crosslinked prior to forming the superabsorbent layer of the present invention.

Cross-linking the carboxyl polyelectrolyte to produce a hydrogel-forming material, now commonly referred to as superabsorbent, and the use of such materials to enhance the absorbency of disposable absorbent products Are known from U.S. Pat. Nos. 3,669,103 and 3,670,731. From U.S. Pat. Nos. 3,980,663 and 4,076,673, it is also known to add a crosslinking agent to a solution of a carboxylated polyelectrolyte and dry and cure the polymer to a superabsorbent. is there. Superabsorbent polymer granules useful in the practice of the present invention are available from a number of manufacturers, such as Dow Chemical (Midland, Michigan), Stockhausen (Greensboro, North Carolin).
a), and from Chemdal (Arlington Heights, Illinois). The conventional granular superabsorbent polymer may use any of a number of multifunctional comonomer crosslinkers well known to those skilled in the art, but the poly (acrylic acid) that is crosslinked during polymerization is Main component. Representative examples of these crosslinkers are N, N'-methylenebisacrylamide, triallylamine, and 1,1,1-trimethylolpropane triacrylate. To make the crosslinked poly (acrylic acid) highly water-swellable, about 50-80% of the carboxyl groups are in the form of sodium, potassium or ammonium salts.

[0015] Superabsorbent granules can also be prepared by crosslinking a suitable water-soluble polymer after polymerization, but this approach has led to the preparation of water-swellable binders from water-soluble polymers in theory. It is suitable. The water-soluble and water-swellable polymers useful in the practice of the present invention can generally be any physiologically acceptable hydrophilic polymer. According to one embodiment of the present invention, a carboxyl polyelectrolyte can be used.

In one embodiment, the polyelectrolyte useful in the present invention is an ammonium or alkali metal salt of a homopolymer of acrylic or methacrylic acid and a copolymer having one or more ethylenically unsaturated comonomers. .

[0017] In one embodiment, the polyelectrolyte is a partially saponified polyacrylate polymer. Prior to saponification, the polymer has (1) an alkyl group of 1 to 1
An alkyl acrylate having 0 carbon atoms, an alkyl methacrylate having an alkyl group having 4 to 10 carbon atoms, or a mixture thereof is used in an amount of 30 to 92 weight percent; 70% by weight; and (3) a mixture of monomers capable of containing from 0 to 15 weight percent omega hydroxyalkyl acrylate, wherein the hydroxyalkyl group has from 1 to 4 carbon atoms.

Examples of useful alkyl acrylates include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and hexyl acrylate. Examples of useful alkyl methacrylates include methyl methacrylate, ethyl methacrylate, hexyl methacrylate, octyl methacrylate, and decyl methacrylate. Examples of useful omega hydroxyalkyl acrylates include 2-hydroxyethyl acrylate, hydroxymethyl acrylate, and 4-hydroxybutyl acrylate.

The olefinically unsaturated carboxylic acids useful in the present invention are mono- or polycarboxylic acids. Examples of monocarboxylic acids include acrylic acid, methacrylic acid, crotonic acid and isocrotonic acid. Examples of polycarboxylic acids include maleic acid, fumaric acid and itaconic acid.

The following is a list of available polymers that can be prepared from readily available monomers and converted to their salt forms. Acrylic acid-acrylate copolymer; acrylic acid-acrylamide copolymer; acrylic acid-olefin copolymer; polyacrylic acid; acrylic acid-vinyl aromatic copolymer; acrylic acid vinyl ether copolymer; acrylic acid-vinyl acetate copolymer; acrylic acid-vinyl alcohol copolymer; And copolymers of methacrylic acid with all the above comonomers.

In one preferred embodiment of the present invention, the carboxyl polyelectrolyte is a hemi-sodium salt of an alternating copolymer of an alpha-olefin and maleic anhydride, wherein the alpha-olefin is ethylene, propylene , 1-butene, isobutylene, styrene, or a mixture of two or more thereof. In another preferred embodiment, the carboxyl polyelectrolyte is poly (acrylic acid) or a copolymer of acrylic acid with an ethylenically unsaturated monomer, the acid portion of which is 40-90 percent neutralized with sodium hydroxide. It was done.

Other hydrophilic polymers such as acrylic copolymers and starch / graft copolymers can also be used. Also, U.S. Patent Publications 3,997,484 and 4
Also useful are the water-insoluble alkali salts of saponified, gelled starch / polyacylonitrile graft polymers taught in U.S. Pat.

Crosslinking agents that can be used to prepare the superabsorbent polymer materials of the present invention are well known in the art. Detailed examples of polyfunctional crosslinkers useful in the present invention for converting the above polyelectrolytes into water-swellable polymers are described in U.S. Pat. No. 2,929,154;
Nos. 3,224,986; 3,332,909; and 4,076,673, which are incorporated herein by reference. These polyfunctional crosslinkers are generally known as polyamide-polyamine epichlorohydrin adducts. Similar crosslinkers are commercially available Kymene 557 and Polycup 172 (Hercu
les Incorporated (Wilmington, Delaware)). The structures of these adducts are well known and are described in ME Coor et al., Journal of Applied Polymer Science, Vol.
17, pages 721-735 (1973).

Detailed examples of bifunctional agents useful in the present invention are polyhaloalkanols, such as 1,
3-dichloroisopropanol, 1,3-dibromoisopropanol; sulfonium zwitterions, such as tetrahydrothiophene adducts of novolak resins; haloepoxyalkanes, such as epichlorohydrin, epibromohydrin, 2-methylepichlorohydrin and epi Iodohydrin; polyglycidyl ether such as 1,4-butanediol diglycidyl ether, glycerin-1,3-diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, neopentyl glycol di Glycidyl ether, polypropylene glycol diglycidyl ether having an epoxy equivalent weight range of about 175 to about 380, about 182
Bisphenol A-epichlorohydrin epoxy resins having an epoxy equivalent weight range of from about 975 to about 975, and mixtures thereof.

As crosslinking agents, monomeric amine-epihalohydrin adducts are also useful. U.S. Pat. Nos. 3,660,431; 3,749,737; and 3,741.
No. 9,738 is incorporated herein by reference, but the sulfonium zwitterions described therein can also be used.

The cross-linking agent may comprise from about 0.05 to about 5 based on the weight of the polyelectrolyte used.
. It can be used in an amount of 0 percent. This is usually sufficient to slightly crosslink the polyelectrolyte. However, one of ordinary skill in the art, based on the guidelines herein and common knowledge in the art, will utilize routine experimentation to optimize each material's ultimate absorption in order to optimize the ultimate absorption of the material. This range for the molecular electrolyte can be adjusted.

The water-swellable (superabsorbent) polymer particles used for preparing the absorber layer of the present invention include:
It is bound by a polymer binder. The term "polymer binder" is capable of binding superabsorbent granules to one another and / or to a fibrous absorbent layer,
Any compound is meant. Even if the superabsorbent particles of the superabsorbent layer are bonded using a water-soluble polymer together with an additional crosslinking agent that can itself be a superabsorbent binder,
It may be bound by latex and / or thermally.

[0028] Natural or synthetic latex is used as the binder. According to a preferred embodiment, the latex has a minimum film forming temperature below room temperature. Examples of suitable latex binders are alkyl acrylate, vinyl acetate and styrene-butadiene polymers and copolymers. The advantage of using latex as a binder in the present invention is described in US Pat. No. 5,128,082.
No. 4,077,064, which was unexpected because it teaches that the application of a latex binder to a web can reduce absorption by superabsorbent particles.

The latex is typically used from about 10 gsm latex per 160 gsm superabsorbent product to about 80 gsm latex per 160 gsm superabsorbent particle, preferably from about 20 to about 40 gsm latex per 160 gsm superabsorbent product. .

[0030] The thermally bonded superabsorbent layer can contain thermoplastic fibers or powders, which are well known to those skilled in the art, and when heated to the melting point of the thermoplastic fibers or powder,
It is known to effect binding.

The polymer binder suitable for the present invention may be a carboxyl polyelectrolyte mixed with a cross-linking agent, which has the property of reacting with a carboxyl group or a carboxylate group of the polyelectrolyte. The polymer binder also comprises
It may be a natural or synthetic latex having a minimum film forming temperature below room temperature. The polymer binder may also be a mixture of a crosslinkable carboxyl polyelectrolyte solution and a latex. This mixture exhibits both properties: the absorbency of the crosslinked polyelectrolyte and the flexibility of the rubbery polymer. The dispersed rubbery phase improves the properties of the superabsorbent coating to bend and bend without being crushed.

[0032] Any other combination of the above polymer binders can be used in the present invention. The superabsorbent layer of the present invention can be prepared by the following method.

In one embodiment of the present invention, the phase of superabsorbent particles is applied to the sheet of fibrous material by methods known in the art. Next, a water-soluble or water-dispersible binder is applied to the layer surface of the superabsorbent particles (for example, by spraying or mixing (doctor)). Prior to application, the binder is, for example, about 1.5 to about 10 times its original volume,
Preferably, it may be foamed to about 3 to 4 times its original volume. This mode of application is usually found to be useful under experimental conditions.

In another embodiment of the present invention, the superabsorbent polymer particles are mixed with a water-soluble or water-dispersible binder and applied to the surface of a sheet of fibrous material. Alternatively, the binder may be foamed first, and then the superabsorbent particles may be added to the foam just prior to application to the fibrous material. This mode of application is suitable for continuous application and is therefore useful for large-scale production.

In one embodiment of the present invention, the foamed water-soluble binder is mixed with a suitable cross-linking agent that cross-links the carboxyl polyelectrolyte into a superabsorbent material upon drying and curing.

In one embodiment of the present invention, the superabsorbent roll product has the structure shown in FIG. 1A. The structure includes a fibrous absorber layer having a superabsorbent layer bonded to one side and a capture layer bonded to the other side. Such acquisition layers are well known to those skilled in the art. In one embodiment, the acquisition layer contains a synthetic fiber selected from the group consisting of polyester, polyamide, and polyolefin. The synthetic fibers can be bound with a latex polymer binder or a thermoplastic binder fiber or a thermoplastic binder powder or a mixture thereof. Alternatively, the acquisition layer can include hardened cellulosic fibers bound with a latex polymer binder or thermoplastic binder fibers or thermoplastic binder powder or a mixture thereof.

In another embodiment of the invention, as shown in FIG. 1B, for example, the superabsorbent roll product of the present invention comprises a dispersion layer between the acquisition layer and the inseparable layer of superabsorbent particles. In. The dispersion layer may be one generally known in the art. For example, the matrix fibers of the dispersion layer may include (i) fluff cellulose fibers (for example, Buck
Buckeye Foley fluff commercially available from eye Technologies, Inc., Memphis, Tennessee
), (Ii) chemically modified fluff cellulose (eg, crosslinked cellulose) or highly purified cellulose (eg, Buckeye HPF), or (iii) a blend thereof. The fibers may be latex bonded fibers, thermally bonded fibers or a combination thereof.

The superabsorbent roll product of the present invention can be used in the manufacture of disposable absorbent articles such as diapers, feminine hygiene products and incontinence products. When used in a superabsorbent product, the superabsorbent layer of the present invention is disposed distally from the user's skin, i.e., distal to the expected liquid attack. The attack side of such a disposable absorbent product preferably comprises a capture layer of bound cellulose or synthetic fibers bound by thermoplastic binder fibers or powders, latex binders or mixtures thereof.

One of the advantages of the present invention is that it eliminates the conventional problems of handling and processing superabsorbent particles encapsulated in a fibrous structure. The present invention provides the absorbent element of a disposable absorbent article in roll form, which allows the manufacturer of the final absorbent product to provide a fiberizing, web forming, and superabsorbent metering device for the manufacture of the product. No need to operate.

Another advantage of the present invention is that the superabsorbent material is present in the absorber configuration in a separate but essential layer, so that liquid enters the acquisition layer and passes through the central or dispersed layer. Is not limited, and the swelling of the superabsorbent itself is not hindered by being trapped in the fiber matrix. Essentially, all the superabsorbent particles touch the binder and the particles are well contained on the web, and the superabsorber addition can be performed as part of the web forming process or in a separate system from the forming equipment. is there. Advantageously, operating this operation remotely of the web forming apparatus avoids contamination by superabsorbent dust, which causes a considerable loss of downtime.

The present invention is further described by the following non-limiting examples.

[0042]

【Example】

EXAMPLES Experimental Procedure (Preparation of Superabsorber Polymer Precursor Solution) A paddle of Kuraray International poly (isobutylene-co-maleic anhydride) sodium half salt (ISOBAM-10 lot no. 825271) Neodol 25-9 from Shell Chemical Company (Houston, Texas) in a 1000 ml resin flask equipped with a stirrer, reflux condenser, temperature controller and heating mantle.
(Nonionic surfactant) Prepared at 25% solids by suspending 154 grams (1.0 mol) of the copolymer in 582 grams of distilled water containing 0.3 grams. Sodium hydroxide in pill or bead form (40.0 grams, 1.0 mol, A
ldrich Chemical (Milwaukee, Wisconsin), lot no. 02420HQ) was added to the slurry and the temperature was raised to 85 ° C. Heat and stir for about 4 hours until the polymer dissolves.
Continued for hours. The prepared solution can be used as a polymer binder for superabsorbent granules, or may be converted to superabsorbent granules using known methods.

Preparation of Superabsorber Precursor Foam 25% of half-neutralized ISOBAM-10 (50.0 grams)
The solution was diluted to 10% solids with 125 grams of distilled water. 0.13 grams of sodium lauryl sulfate (anionic surfactant) was added to stabilize the foam. Crosslinking agent (KYMENE 557, Hercules Incorporated (Willmington, Delaware)) 1
. A 10% solution of 0 wt% polymer (1.25 grams) was added and agitated quickly with a perforated paddle while flowing nitrogen subsurface to promote foaming. Stirring was continued until the foam volume was approximately three times the stock volume. The foam can be used as it is, or
It may be blended with a latex to provide flexibility to the polymer after drying and curing. When adding latex, the water in the latex will be subtracted from the distilled water in the formulation.

Foam Coating of Nonwoven Fabric A calculated weight of foam was applied uniformly on the nonwoven fabric to give the desired polymer loading and dried at 125 ° C. in a combined convection oven. For example, on a 14.times.14 inch pad, for 40 gsm, the total amount of solids is about 5.06 grams (50.50 grams).
6 grams of foam). During the drying step, the crosslinker is activated and the polymer becomes a superabsorbent. Commercially available granular superabsorbent used in this experiment is FAVOR ^R SXM 70 made of Stockhausen, surface - crosslinked, a conventional superabsorbent acrylic acid based.

(Saturation Performance) The sample was cut into 2.25 inch squares, placed in a disposable weighing pan,
Was also weighed to the nearest centigram. Excess saline (0.9% NaCl) was added and impregnated for 30 minutes. Excess saline was discarded and the dish was placed on its edge for 5 minutes. All exuded water was discarded, and the dishes and pads were weighed. Pad saturation performance (grams of saline absorbed per gram of pad) is the total weight of wet pad minus the weight of dry pad divided by the weight of dry pad. .

Retention Performance The pad used in the saturation performance test was placed on four layers of dried pulp sheet (functioning as blotter) and placed under a load of 0.9 psi for 5 minutes. Weigh the compressed pad, and the holding performance subtracts the dry pad weight from the compressed pad weight,
This is divided by the weight of the dry pad.

Acquisition Rate Wrap a 4 inch square pad with standard diaper coverstock material and apply 0.3
Placed under psi load. The center of the weight is a 1.5 inch diameter target zone with a 4 inch high clear dosing tube. 0.9 ml of 0.9% saline
Was injected into the cylinder and the time of absorption was recorded. This was repeated twice more at one minute intervals. The speed in ml / s of the third attack indicates the capture rate of the sample.

(Multiple Dose Rewet) A diaper was placed on a laboratory bench, and in the center thereof, a 50 ml diaper was prepared from a measuring cylinder.
0.9% NaCl was poured. Twenty minutes later, a tare-weighed 11 cm diameter Whatman
A bundle (10-12) of No. 3 filter paper was placed in the target area and placed under 0.8 psi pressure with a 9 cm diameter weight for 1 minute. The weight of saline captured by the filter paper is the re-release. The operation was repeated twice with a few more filter papers, since re-release usually increases after repeated attacks.

Experimental Results All controls and examples except the commercial product Zorbcor were made on a typical laboratory airlaid web former, but a mixture of capture layer fibers and binder fibers was first made and then fluff. And a binder fiber was prepared. Control 1 (Zorbcor ^R 5902, Buckeye Technologies Inc. (Memphis, TN)
Was 450 gsm in total. It contained 183 gsm of granules substantially uniformly dispersed throughout the pad. This material is intended for discontinuous products which inherently require very high absorption performance. Control 1 with 150 gsm fiber (
A laboratory made pad containing 50 gsm of a 90/10 crosslinked cellulose / bicomponent binder fiber layer and 100 gsm of a 95/5 fluff / bicomponent binder fiber layer). Bicomponent fibers (Type T-255, Hoechst-Trevira (Charlotte, North Caroli
na)) is a low melting point polyethylene sheath covering the polyester core. The newly created absorber structure was heated to about 160 ° C. to dissolve the binder fibers. On the fluff side, 160-180 gsm of superabsorbent granules were applied, and then a binder preparation was applied several times to a total of 350 gsm. Specific latex used in these examples are RHOPLEX ^R HA-8 manufactured by Rohm and Haas (Philadelphia, Pennsylvaia) .
Any other latex typically used in nonwoven manufacturing would be effective.
The superabsorbent is FAVOR ^R SXM70 and is available from Stockhausen Inc. (Greenboro, North Carol
Ina) is a surface-crosslinked granular material. For Examples 4 and 5, the operations of Examples 2 and 3 were repeated except that a 180 gsm granular superabsorbent was applied to the airlaid nonwoven prior to the application of the binder. All controls and examples, except for the commercial product Zorbcor, were made on a typical laboratory airlaid web former, but a mixture of capture layer fibers and binder fibers was first made, followed by a mixture of fluff and binder fibers. Created.

Control 3 (Vizorb ^R 3900, manufactured by Buckeye Technologies) contains 120 gsm (
Superabsorbent (30 gsm), usually intended for use in feminine hygiene products. Vizorb was compared to pilot line manufactured airlaid, an 80 gsm fluff and styrene-butadiene latex binder. The smooth side was treated with superabsorbent granules and foam / latex.

[0051]

[Table 1]

Examples 1-3 showed high absorbency per gram with much lower fiber usage than the commercial sample control 1. Example 3 (latex binder for superabsorbent) also has less superabsorbent than Control 1. Example 5 with a superabsorbent loading comparable to Control 1 showed significantly higher performance. The capture rate (absorbent pad, especially a measure of the porosity of the top) is higher in the examples than in the commercially available controls, which is because the controls do not have a separate capture layer and are evenly distributed throughout the pad. This is because it has absorbent granules. Even Example 6, which does not have a separate capture layer, outperforms Control 3 in capture rate and the uniform distribution of superabsorbent particles in Control 3 consists of all particles bound to the lower surface of the absorber structure This shows that the capture is inhibited as compared to the ones.

For Control 4 and Examples 7-9, crimped polyester staple fibers (T-224, Hoechst-Trevira (Salisbu
ry, NC) was blended into a bicomponent fiber and the procedure of Example 1-3 was repeated except that a synthetic capture layer was obtained after heating to 160 ° C.

[0054]

[Table 2]

The inseparable, crimped polyester / two-component capture layer showed a significant capture rate as compared to the cured cellulose capture layer used in Control 2 of Table 1 and in Examples 1-5.
Since Examples 7-9 capture liquid more quickly than Control 4, the superabsorber layer also appears to contribute by draining the capture layer and the intermediate layer.

Performance is not the only critical property in a diaper design. In order to maintain good comfort and skin condition, the product should have a low degree of re-release under pressure after multiple attacks and keep the skin dry. Prototype diaper components were manually made and tested for re-release and capture (penetration) by multiple attacks using 50 ml of 0.9% sodium chloride. To make a test diaper (4 inches x 14 inches), a piece of carrier tissue or airlaid was placed on a polyethylene backing sheet, followed by a capture / distribution layer with superabsorbent attached, and a regular heat bonded polypropylene. Card web cover stock (Fiber Tech, Soft Tou
ch. available from PGI Nonwovens (available from Landesville, NJ), and the entire configuration was sealed to create a rectangular diaper without rubber or leg cuffs. Proctor &
A commercial diaper under the trade name PAMPERS Baby Dry 3 from Gamble was tested with a laboratory prototype after the leg cuff and rubber had been removed and flattened. In Example 10, the 250 gsm superabsorbent is a 25 gsm poly (vinyl acetate) copolymer latex (AirFlex 108, Air Products and Chemicals, Inc.
Allentown, PA), which is bonded to the bottom of the acquisition / distribution layer, leaving a 1.5 inch wide gap in the SAP layer spanning the length of the diaper. ADL is a 6gsm poly (
Vinyl acetate) copolymer latex (AirFlex 192, Air Products and Ch)
emicals, Inc.) has released cellulose fluff (HPF mercerized pulp, Buckeye Techno
logies, Inc. (Memphis, TN) and Type T-255 bicomponent fiber (Hoechst-Trevira (C
Harlotte, North Carolina) 34 gsm crimped polyester bonded onto 40 gsm 90/10 heat bonded mixture with airlaid distribution layer. The trapping layer with superabsorbent bonded was tested on a 50 gsm cellulose fluff-two component airlaid distribution layer. Example 11 was similar except that 15 gsm of latex was used in place of 25 gsm and SAP binder. Example 12 was the same as Example 10 except that the bottom distribution layer of the diaper was 30 gsm carrier tissue pieces instead of 50 gsm airlaid.

[0057]

[Table 3]

Table 3 shows that the diapers according to the invention have an advantage over these commercially available products in these liquid treatment tests, despite their significantly lower superabsorbent content.

[Brief description of the drawings]

FIG. 1A is a schematic diagram illustrating the structure of a superabsorbent roll product prepared according to one embodiment of the present invention. B is a schematic diagram illustrating the structure of a superabsorbent roll product prepared according to one embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme court ゛ (Reference) // C08F 20/04 (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR, BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, D, GE, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN , MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Steve Leptic Canada British Columbia Delta Cirtisix-Sixty-Seventh Street (no address) (72) Inventor John P. Elsparmer United States Tennessee 38002 ・Lakeland Elm Point Cove 9580

Claims (25)

[Claims] 1. A superabsorbent roll product suitable for the manufacture of disposable personal care products with a separate superabsorbent structure. 2. The superabsorbent roll product of claim 1, wherein said superabsorbent structure is inseparably bonded to a fibrous absorbent layer. 3. The superabsorbent roll product of claim 1, wherein the superabsorbent structure is located on the distal side of the roll product from a user. 4. The superabsorbent roll product of claim 1, wherein the superabsorbent structure comprises a particulate carboxyl polymer electrolyte, wherein the electrolyte is crosslinked. 5. The superabsorbent roll product of claim 4, wherein the polyelectrolyte is selected from the group consisting of poly (acrylic acid) polymers and copolymers. 6. The superabsorbent roll product of claim 4, wherein said polyelectrolyte is bound by a polymer binder. 7. The superabsorbent roll product of claim 6, wherein the polymer binder is a natural or synthetic latex, wherein the latex has a minimum film forming temperature below room temperature. 8. The superabsorbent of claim 6, wherein the polymer binder comprises a crosslinker with a carboxyl polyelectrolyte, the crosslinker having the property of being reactive with carboxyl or carboxylate groups of the polyelectrolyte. Body roll products. 9. The polymer binder comprises a mixture of a natural or synthetic latex having a minimum film-forming temperature, a carboxyl polyelectrolyte, and a crosslinking agent having the property of being reactive with carboxyl or carboxylate groups. 7. The superabsorbent roll product of claim 6. 10. The superabsorbent roll product of claim 9, wherein said crosslinking agent is a polyfunctional crosslinking compound. 11. The superabsorbent roll product of claim 2, further comprising an acquisition layer. 12. The superabsorbent roll product of claim 11, further comprising a distribution layer. 13. The superabsorbent roll product of claim 11, wherein said acquisition layer comprises synthetic fibers selected from the group consisting of polyesters, polyamides, and polyolefins. 14. The superabsorbent roll product of claim 13, wherein said synthetic fibers are bonded with a latex polyamide binder. 15. The superabsorbent roll product of claim 12, wherein the synthetic fibers are bonded with thermoplastic binder fibers or thermoplastic binder powder. 16. The superabsorbent roll product of claim 12, wherein the synthetic fibers are bonded with a mixture of a thermoplastic binder and a latex binder. 17. The superabsorbent roll product of claim 11, wherein the acquisition layer comprises hardened cellulose fibers. 18. The superabsorbent roll product of claim 15, wherein the cured cellulosic fibers are bonded with a latex polymer binder. 19. The superabsorbent roll of claim 11, wherein the acquisition layer comprises both synthetic and cellulosic fibers, wherein the fibers are latex bonded, thermally bonded, or both. Product. 20. The superabsorbent roll product of claim 15, wherein the cured cellulosic fibers are bound with thermoplastic binder fibers or thermoplastic binder powder. 21. The superabsorbent roll product of claim 4, wherein said carboxyl polyelectrolyte is attached in a discontinuous manner. 22. A disposable absorbent sanitary article prepared from the roll product of claim 1. 23. The disposable absorbent sanitary article of claim 22, which is a diaper. 24. The disposable absorbent sanitary article of claim 22, which is a sanitary napkin. 25. The disposable absorbent hygiene article of claim 22, which is an adult incontinence product.