|Número de publicación||US3888256 A|
|Tipo de publicación||Concesión|
|Fecha de publicación||10 Jun 1975|
|Fecha de presentación||13 Feb 1973|
|Fecha de prioridad||22 Feb 1972|
|También publicado como||DE2208126B|
|Número de publicación||US 3888256 A, US 3888256A, US-A-3888256, US3888256 A, US3888256A|
|Cesionario original||Hans Studinger|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (6), Citada por (77), Clasificaciones (21)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
United States Patent Studinger 1 June 10, 1975 15 1 LAYERED ABSORBANT PAD MATERIAL 3.645.836 2 1972 Torr 161/151 3.664.343 5/1972 Assarsson .7 128/284  Inventor. Hans Studlnger, 6 Johanmsstrasse, 3669103 6/1972 Harp:r e a] [28,284 X 8500 Numberg- Germany 3,670,731 6/1972 Harmon 128/284 Feb. 3, 3,686,024 Nankee Ct 3| 128/284 1 1 PP 332,229 Primary Examiner-George F. Lesmes Assistant ExaminerL. T. Kendell  Foreign Application Priority Data Attorney, Agent, or Firm-Ross, Ross & Flavin F b. 22, 1972 G 2208126 6 many 57 ABSTRACT  US. Cl. 128/296; 128/284; 128/287; A layered bsorbent pad material comprising an ab- 128/290 R; 428/87; 428/475; 428/510 sorbent layer disposed between upper and lower sur-  Int. Cl. 1332b 5/16; A61f 13/16 face layers, is provi between h pper rface  Field of Search 161/162, 168, 169, 170, layer and the absorbent layer, with a layer of particu- 161/152, 156; 128/284, 287, 290 R late swelling substance which swells subsequent to the material absorbing liquid. and thereafter prevents liq-  References Cited uid being displaced back into the upper surface layer UNITED STATES PATENTS upon squeezing of the material.
3,344 789 10/1967 Arnold et a1 128/287 1 Claim, 5 Drawing Figures LAYERED ABSORBANT PAD MATERIAL This invention relates to layered absorbent pad material for hygienic purposes such as absorbent, sanitary or invalid's underlays, diapers, sanitary towels and the like, and comprises an absorbent layer disposed between an upper surface layer and a lower surface layer and incorporating a swelling substance. As used herein, the term swelling substance" means a substance which swells upon absorbing a liquid, such as water, the water being retained by adsorption.
Absorbent pads of this kind are already known. For example in German Patent Specification No. 489308 it has been proposed to incorporate into absorbent pads, which are to be used, for example, for the production of sanitary towels and for other sanitary and surgical purposes, in order to increase their absorptive capacity, adsorptive substances which are capable of combining chemically with water contained in the liquid expected to be absorbed by the pads. Organic natural products, such as potato flour, cereal starch, gelatine and the like, have been proposed as agents on this score.
Hydrophilic colloids of this kind are not, however, generally acceptable as swelling substances in hygienic or sanitary articles of the kinds mentioned. Only in recent times has it been possible to find substances having better absorptive capacities and having in addition, the property of being substantially immune to the growth of bacteria. Thus, for example in German Patent Specification No. l,079,796 it is proposed to use, as swelling substance, carboxymethyl cellulose of which the degree of etherification is adjusted to values from 0.05 to 0.3. For the same purposes, in German Offenlegungsschrift No. 1,642,072, polyacryl amides, as well as sulphonated polystyrenes, having a specific chemical structure are recommended. Finally, it can be understood from German Offenlegungschrift No. 2,048,721 that cross-linked polymers of the polyethylene oxide type or of the polyethylene imine type are also suitable for the same purpose.
In most of these prior documents, it is proposed that the swelling substances should be in the form of powder or granulate, and that they should be accommodated either in a special bag or envelope of a material which is pcrvious to liquid, or to introduce the swelling substances into the absorbent pad in a mixture with cellulose wadding. In the aforesaid German Offenlegungschrift No. 1,642,072, it has also been proposed initially to coat a suitable liquid-pervious foil with a layer of adhesive and then to sprinkle the layer of adhesive with swelling-substance in powder form. The individual particles of the powder then stick fast by their undersides on the layer of adhesive and are thus retained in position. The flat product obtained in this way is then introduced into the absorbent layer at the side which lies downwards in use or is incorporated into the centre of the absorbent layer.
In comparison with the conventional absorbent hygienic pads containing cellulose wadding, absorbent pads containing a swelling substance have a considerably higher liquid absorption capacity. Whereas cellulose can, as a rule, absorb only about 20 grammes of water per gramme of cellulose, the liquid absorption capacity of the said swelling substances can amount to up to I50 grammes of water per gramme of swelling substances depending on the chemical nature of the substance. Added to this is the fact that the water is chemically completely adsorbed by the swelling substances and is retained by chemical combination e.g. by principal valencies. This means that the swelling substance, once it has taken up the water does not release it again, even under pressure loading or upon squeezing, which improves the utility of such substances. In contrast thereto, the water in paper or cellulose is largely retained by secondary valency forces or by capillary forces, which means there is much weaker retention so that such substances will readily give up the absorbed liquid under the effect of pressure, like a sponge.
Despite the considerable advantages which absorbent pads, laden with swelling substances, have in the hygienic or sanitary field, naturally the liquid absorptioin capacity of such pads is likewise limited. When the swelling substance has swollen to its maximum, it is saturated and can no longer absorb any further liquid which may be present. This excess liquid is stored in the pad in the conventional manner, like a sponge, by the cellulose wadding or crepe paper layers which are also present, and is yielded up again when the absorbent pad is subjected to pressure or squeezed. Such squeezing action cannot be avoided in the practical use of the absorbent pads and it therefore necessarily leads to ex' pression of liquid from the pads and to the formation of pools of liquid on the surfaces of the pads.
Having regard to this state of the prior art the problem still exists of providing a faced or enveloped absorbent pad containing a swelling substance, for hygienic purposes, the liquid retention capacity of which is improved in comparison with the known pads.
In accordance with the invention, this problem is solved in that the pad material incorporates a particulate swelling substance is arranged exclusively or additionally in one of the layers, lying at the top in use, of the absorbent body or of the envelope and in that the distribution of the particles throughout the layer of swelling substance is such that the spacing between adjacent particles is no greater than half of the particle diameter increase which occurs upon swelling of said particles. With such arrangement, upon swelling the particles coalesce, after the fashion of a jelly, and form a barrier layer which is impervious to liquid.
ln the practical use of absorbent pads constructed in this way, upon wetting of the pad the wetting liquid initially enters in the conventional manner into the absorbent pad and flows through the layer of swelling sub stance arranged at the top or largely at the top, resulting in the particles of swelling substance being moistened and slowly beginning to swell. Surplus liquid flows past the particles of swelling substance and into the absorbent layer lying therebelow, which absorbent layer consists, for example of cellulose wadding, crepe paper plies or the like.
The swelling procedure itself may last. for example, from one to five minutes depending on the fineness of grain of the swelling substance. A considerable increase in diameter of the individual particles occurs, so that these, because of their density of distribution, coalesce into a poreless liquid-impervious gel-like barrier layer. lf subsequently to the swelling a fairly severe pressure loading is imposed on the pad or the pad is squeezed locally, the liquid stored like a sponge by the absorbent layer (cellulose wadding layer or crepe paper layer) is no longer able to penetrate the barrier layer and to rewet the exterior of the absorbent pad outwardly. What is advantageous in this connection is the fact that once the chemical reaction of liquid adsorption is once initiated, the swelling proceeds initially slowly and then comparatively rapidly. Towards the end of the reaction, the speed of swelling dies away, which leads to the fact that the gel layer, even though it may have coalesced to such an extent that it will not let liquid pass through outwardly from the interior of the absorbent layer, can still take up relatively small quantities ofliquid still present on the outside of the absorbent pad or which may subsequently arise. An invalid or sanitary underlay, diaper, sanitary towel or the like, conforming to the invention therefore displays the advantageous property that it can initially absorb a relatively large quantity of liquid during which the swelling material layer correspondingly swells and coalesces despite considerable pressure loading, to form an effective sealing layer or skin with the result that the top surface of the pad becomes dry again.
It is advantageous if the swelling substance is arranged directly below the filter layer or one of the upper surface layers of the pad material, and that it should be in one or more layers itself. To this end, the swelling substance should preferably have a granulate form and be held fast, by way of example adhered, on a liquid-pervious carrier or support sheet. This carrier sheet or several of these sheets arranged one above the other in layers can then be introduced in the manufacture of the absorbent pad.
It is furthermore possible to confine the swelling substance between two layers of cellucotton (or artificial cotton) and to introduce it in this form into the absorbent pad during the manufacture. In this connection, the cellucotton acts as a support and filter layer which prevents the swelling substance from escaping from the absorbent pad.
The invention will be described further, by way ofexample, with reference to the accompanying drawings, in which:
FIG. 1 is an enlarged diagrammatic sectional view of a preferred form of the absorbent pad material of the invention;
FIG. 2 is a view similar to FIG. 1, but showing the material subjected to pressure after wetting and before completion of swelling;
FIG. 3 is a view similar to FIG. 1 but showing the material after swelling has taken place;
FIG. 4 is a view similar to FIG. 3, but showing the material subjected to pressure loading; and
FIG. 5 is a diagrammatic plan illustrating the particle distribution in the swelling substance layer in the material of FIGS. 1 to 4.
The layered absorbent pad material illustrated in the drawings comprises a plurality of superimposed layers consisting of flat areal structures or sheets, and absorbent substances. Upper surface layer 1 is in the form of a plasticsbound fibre fleece or web which imparts to the entire absorbent pad material a textilelike texture which is kind to the skin. Underneath this fleece substance layer 1 there is disposed one, or several, layers 2 of cellucotton acting as a filter layer and serving to prevent swelling substances (yet to be described). in the unswollen state, from escaping from the material, eg. as a result of rough treatment of the absorbent pad material.
Beneath the layer or layers 2 of cellucotton there is disposed one or several layers 3 of swelling substance,
which are preferably prepared as has already been described above. In this connection, the powdery or granular swelling substance (which may consist for example of polyacrylamide, sulphonated polystyrene or other suitable substance) is fixed, for example adhered, to a carrier sheet of cellucotton. Underneath the layer 3 of swelling substance there is disposed a relatively thick layer 4, which consists of one or morelaps of cellulose wadding. Crepe paper can, if desired, be incorporated into this layer; furthermore, intermediate layers of cellucotton can be present therein, those serving for example as carriers for disinfecting or deodorising substances.
Finally, arranged as lower layer 5 there are once more one or more surface layers which may also consist of cellucotton, plastics-bound fibre fleece or which may be of liquid-impervious foil, for example thin polyethylene foil.
Should the absorbent pad material be wetted, in other words if a liquid, for instance water, impinges in the direction of arrows 6 (FIG. I) on the upper surface layer 1 of the pad, this liquid is absorbed instantaneously by the pad and becomes distributed in the ab sorbent layer 4, as is indicated in FIG. I by arrows 7. Also the layer 3 of swelling substance is penetrated and the particles of swelling substance are moistened.
If, before the swelling substance of the layer 3 has swollen, the pad is subjected to pressure as indicated in FIG. 2 by the arrow 8, part of the liquid stored in the pad by the absorbent layer 4 is expelled after the manner of squeezing a sponge. This expelled liquid flows partially away from the location at which the pressure is applied, as is indicated in FIG. 2 by the arrows 9. Part of this expelled liquid will, however, as indicated by the arrows 10 in FIG. 2, penetrate the still comparatively pervious layer 3 of swelling substance and the layers 2 and 1 arranged thcreabove and flow back onto the upper surface of the absorbent pad. There it can form a pool 11, which, of course, is undesirable.
Contact of the liquid with the swelling substance layer 3 results in the particles of the swelling substance absorbing the liquid and beginning to swell. This swelling proceeds slowly at first. After a few minutes, however the reaction between the particles of swelling substance and the liquid will have progressed to such an extent that, as is shown in FIG. 3, the particles will have considerably increased in diameter. As a result, the swollen particles coalesce into a jellylike liquid impervious layer 3' (FIGS. 3 and 4) which creates a barrier for the liquid which is already present in the suction layer 4. The layer 3' of swelling substance can still absorb small quantities of liquid from above which leads to the fact that the upper fleece material layer 1 as well as the cellucotton layer 2 yield their residual liquid content to the layer 3' of swelling substance and are caused to dry out. Should the pad now be squeezed or subjected to pressure loading, as indicated in FIG. 4 by the arrow 8, the layer 3' remains liquid-impervious so that no liquid can be expressed upwards out of the absorbent layer 4, and the diaper, invalid underlay, sanitary towel or the like remains dry even if subjected to violent treatment resulting in considerable surface deformation of the pad.
The embodiment shown in the drawings is given only by way of example and variations may be made thereto. For example, it is possible to arrange the layer 3 of swelling substance not as shown above the absorbent pad layer 4, but to accommodate it within this layer, but near to its upper surface. This would be the equivalent, of course, to providing a further thin absorbent layer between the swelling substance layer 3 and the cellucotton layer 2. If the layer 3 of swelling substance were, for example, accommodated in the centre of the absorbent layer or in the latter near to its lower surface, naturally the drying and barrier effect above-discussed would not be achieved. However, this does not preclude the possibility of providing additional swelling substance layers in the centre and/or near the bottom surface of absorbent layer, over and above the layer 3 at or near the top surface of the absorbent layer 3, if this is desired and is acceptable for economic reasons.
In FIG. 5, several particles 12 of the swelling sub stance are shown, very diagrammatically, as lying sideby-side. In fact, the particles of swelling substance naturally will not be regularly-disposed as illustrated nor will they be in the form of spheres, but will be more or less non-uniformly shaped structures; the fundamental requirement for the distribution of the particles remains however,, the same. The particles 12 of swelling substance (which are shown in their non-swollen conditions in full lines) absorb water in the swelling procedure, and combine chemically therewith; as a result they increase in volume and consequently in diameter as indicated in dotted lines at 12'. An essential feature of the absorbent pad material of this invention is that the distribution of the unswollen particles ll of swelling substance is such that at no point throughout the layer is the spacing 13 of the particles 12 of swelling substance from one another greater than half the increase in diameter which occurs upon swelling thereof. Only with observance of this condition is it ensured that the particles of swelling substance coalesce tightly and thus form the liquid-impervious barrier layer 3'. Theoretically there could remain, between the coalesced particles 12, a free space which considered twodimensionally is an enveloping rectangle. but considered three-dimensionally is an enveloping octahedron. Microscopic observations show, however, that this free space in fact does not remain, but becomes filled as a result of deformation of the swollen particles, and the entire layer thus coalesces into a uniform mass.
To ensure that no liquid can be expressed from the pad when subjected to all-over pressure, or pressure applied over large areas thereof, the pad or the pad ma terial may be enveloped or faced, except at its upper surface layer, by an additional water-impervious envelope or foil.
1. A layered absorbent hygienic pad of joinedtogether layers comprising:
an uppermost surface layer of plastics-bound fiber fleece, a next-adjacent carrier filter sheet of cellucotton, a next-adjacent layer of granulated particulate swelling substance formed from the group consisting of polyacrylamide or sulphonated polystyrene with spacings between adjacent particles,
an absorbent layer consisting of one or more laps of cellulose wadding and being free of any swelling substance, and a lowermost surface layer of a material formed from the group consisting of a plasticsbound fiber fleece or a liquidimpervious foil with the distribution of the particles of the layer of the swelling substance being such that the spacing between adjacent particles is no greater than half of the particle diameter increase realized upon parti cle swelling.
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US3344789 *||29 Dic 1964||3 Oct 1967||Azur Associates||Diaper with film enclosed absorbent|
|US3645836 *||5 Sep 1968||29 Feb 1972||David Torr||Water-absorption fibrous materials and method of making the same|
|US3664343 *||6 Oct 1969||23 May 1972||Union Carbide Corp||Disposable articles|
|US3669103 *||31 May 1966||13 Jun 1972||Dow Chemical Co||Absorbent product containing a hydrocelloidal composition|
|US3670731 *||20 May 1966||20 Jun 1972||Johnson & Johnson||Absorbent product containing a hydrocolloidal composition|
|US3686024 *||24 Feb 1970||22 Ago 1972||Dow Chemical Co||Process of making a water-absorbent coated article and resultant product|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US3921232 *||20 Feb 1975||25 Nov 1975||Procter & Gamble||Self-inflating structure|
|US4054141 *||28 Feb 1977||18 Oct 1977||Julius Schwaiger||Absorptive material for hygienic purposes|
|US4055180 *||23 Abr 1976||25 Oct 1977||Colgate-Palmolive Company||Absorbent article with retained hydrocolloid material|
|US4055184 *||10 May 1976||25 Oct 1977||Colgate-Palmolive Company||Absorbent pad|
|US4105033 *||28 Mar 1977||8 Ago 1978||Personal Products Company||Powdered grafted cellulose|
|US4144886 *||26 Oct 1976||20 Mar 1979||Hoechst Aktiengesellschaft||Absorbent laminate|
|US4235237 *||8 May 1978||25 Nov 1980||Johnson & Johnson||Absorbent open network structure|
|US4293609 *||30 Jun 1980||6 Oct 1981||The Dow Chemical Company||Flexible absorbent laminates|
|US4297410 *||2 Oct 1979||27 Oct 1981||Kao Soap Co., Ltd.||Absorbent material|
|US4381784 *||17 Feb 1981||3 May 1983||Kimberly-Clark Corporation||Sanitary appliance containing blood gelling agent|
|US4500315 *||8 Nov 1982||19 Feb 1985||Personal Products Company||Superthin absorbent product|
|US4537590 *||20 Jun 1983||27 Ago 1985||Personal Products Company||Superthin absorbent product|
|US4540454 *||10 Sep 1984||10 Sep 1985||Personal Products Company||Method of forming a superthin absorbent product|
|US4568341 *||10 Mar 1983||4 Feb 1986||James G. Mitchell||Absorbent pads, incontinence care products and methods of production|
|US4578068 *||20 Dic 1983||25 Mar 1986||The Procter & Gamble Company||Absorbent laminate structure|
|US4600458 *||2 Jul 1985||15 Jul 1986||The Procter & Gamble Co.||Method of making an absorbent laminate structure|
|US4846813 *||25 Sep 1985||11 Jul 1989||Kimberly-Clark Corporation||Self-sealing fluid absorbent article|
|US4985023 *||23 Oct 1989||15 Ene 1991||Dow Corning Corporation||Antimicrobial superabsorbent articles|
|US5013309 *||24 Abr 1989||7 May 1991||Kem-Wove Incorporated||Incontinent pad with high absorbent packet|
|US5300104 *||26 Ene 1993||5 Abr 1994||Yvon Gaudreault||Thermotherapeutic pad|
|US5300192 *||17 Ago 1992||5 Abr 1994||Weyerhaeuser Company||Wet laid fiber sheet manufacturing with reactivatable binders for binding particles to fibers|
|US5308896 *||17 Ago 1992||3 May 1994||Weyerhaeuser Company||Particle binders for high bulk fibers|
|US5330817 *||15 May 1989||19 Jul 1994||Milliken Research Corporation||Incontinence pad|
|US5352480 *||17 Ago 1992||4 Oct 1994||Weyerhaeuser Company||Method for binding particles to fibers using reactivatable binders|
|US5395359 *||27 Sep 1993||7 Mar 1995||Kao Corporation||Absorbent article|
|US5447788 *||16 May 1994||5 Sep 1995||Kimberly Clark Corporation||Porous, nonwoven liquid-activated barrier|
|US5447977 *||15 Nov 1993||5 Sep 1995||Weyerhaeuser Company||Particle binders for high bulk fibers|
|US5538783 *||17 Ago 1992||23 Jul 1996||Hansen; Michael R.||Non-polymeric organic binders for binding particles to fibers|
|US5543215 *||17 Ago 1992||6 Ago 1996||Weyerhaeuser Company||Polymeric binders for binding particles to fibers|
|US5547541 *||16 Feb 1994||20 Ago 1996||Weyerhaeuser Company||Method for densifying fibers using a densifying agent|
|US5547745 *||17 Ago 1993||20 Ago 1996||Weyerhaeuser Company||Particle binders|
|US5558655 *||3 May 1994||24 Sep 1996||Confab, Inc.||Absorbent article with dry surface composite construction|
|US5571618 *||17 Jun 1994||5 Nov 1996||Weyerhaeuser Company||Reactivatable binders for binding particles to fibers|
|US5589256 *||17 Ago 1992||31 Dic 1996||Weyerhaeuser Company||Particle binders that enhance fiber densification|
|US5607759 *||17 Ago 1993||4 Mar 1997||Weyerhaeuser Company||Particle binding to fibers|
|US5609727 *||7 Feb 1994||11 Mar 1997||Weyerhaeuser Company||Fibrous product for binding particles|
|US5611885 *||7 Jun 1995||18 Mar 1997||Weyerhaeuser Company||Particle binders|
|US5614570 *||4 Abr 1995||25 Mar 1997||Weyerhaeuser Company||Absorbent articles containing binder carrying high bulk fibers|
|US5641561 *||17 Ago 1993||24 Jun 1997||Weyerhaeuser Company||Particle binding to fibers|
|US5672418 *||17 Ago 1993||30 Sep 1997||Weyerhaeuser Company||Particle binders|
|US5677028 *||9 Abr 1996||14 Oct 1997||Wearever Health Care Products, Llc||Absorbent material|
|US5693411 *||17 Ago 1993||2 Dic 1997||Weyerhaeuser Company||Binders for binding water soluble particles to fibers|
|US5778457 *||6 Feb 1996||14 Jul 1998||Intellitecs International Ltd.||Hygienic panty and quick-attach pad|
|US5789076 *||7 May 1997||4 Ago 1998||Showa Denko K.K.||Liquid-absorbent sheet and method for storing food using the same|
|US5789326 *||19 Nov 1996||4 Ago 1998||Weyerhaeuser Company||Particle binders|
|US5807364 *||4 Abr 1995||15 Sep 1998||Weyerhaeuser Company||Binder treated fibrous webs and products|
|US5810798 *||15 Ene 1997||22 Sep 1998||Kimberly-Clark Worldwide, Inc.||Absorbent article having a thin, efficient absorbent core|
|US5819317 *||20 Dic 1995||13 Oct 1998||Intellitecs International Ltd.||Infant t-shirt|
|US5879487 *||17 Jul 1997||9 Mar 1999||Wearco Llc||Absorbent material and method for making same|
|US5906876 *||17 Jul 1996||25 May 1999||Intellitecs International, Inc.||Absorbent fabric and undergarments incorporating the fabric|
|US5998032 *||5 Jul 1996||7 Dic 1999||Weyerhaeuser Company||Method and compositions for enhancing blood absorbence by superabsorbent materials|
|US6071549 *||6 Ago 1998||6 Jun 2000||Weyerhaeuser Company||Binder treated fibrous webs and products|
|US6270893||7 Mar 1994||7 Ago 2001||Weyerhaeuser Company||Coated fiber product with adhered super absorbent particles|
|US6340411||7 Oct 1998||22 Ene 2002||Weyerhaeuser Company||Fibrous product containing densifying agent|
|US6383960||3 Mar 2000||7 May 2002||Kimberly-Clark Worldwide, Inc.||Layered absorbent structure|
|US6391453 *||4 Mar 1998||21 May 2002||Weyernaeuser Company||Binder treated particles|
|US6395395||6 Dic 1999||28 May 2002||Weyerhaeuser Company||Method and compositions for enhancing blood absorbence by superabsorbent materials|
|US6416697||3 Dic 1999||9 Jul 2002||Kimberly-Clark Worldwide, Inc.||Method for obtaining a dual strata distribution of superabsorbent in a fibrous matrix|
|US6425979||3 May 2001||30 Jul 2002||Weyerhaeuser Company||Method for making superabsorbent containing diapers|
|US6437214||6 Ene 2000||20 Ago 2002||Kimberly-Clark Worldwide, Inc.||Layered absorbent structure with a zoned basis weight and a heterogeneous layer region|
|US6461553||31 Ene 1997||8 Oct 2002||Weyerhaeuser||Method of binding binder treated particles to fibers|
|US6521087||4 May 2001||18 Feb 2003||Weyerhaeuser Company||Method for forming a diaper|
|US6521339||18 May 2000||18 Feb 2003||Weyerhaeuser Company||Diol treated particles combined with fibers|
|US6596103||1 Nov 2000||22 Jul 2003||Weyerhaeuser Company||Method of binding binder treated particles to fibers|
|US6627249||18 Mar 2002||30 Sep 2003||Weyerhaeuser Company||Method of enhancing blood absorbence by superabsorbent material|
|US6710225||3 Mar 2000||23 Mar 2004||Kimberly-Clark Worldwide, Inc.||Layered absorbent structure with a zoned basis weight|
|US7144474||15 Ago 2000||5 Dic 2006||Weyerhaeuser Co.||Method of binding particles to binder treated fibers|
|US7838155 *||5 Ago 2005||23 Nov 2010||Sony Corporation||Aqueous electrolyte solution absorber and method for producing it|
|US20050000669 *||14 Mar 2003||6 Ene 2005||Hugh West||Saccharide treated cellulose pulp sheets|
|US20050010183 *||24 Jun 2003||13 Ene 2005||Weyerhaeuser Company||Absorbent structure for absorbing blood|
|US20050031841 *||5 Ago 2003||10 Feb 2005||Weyerhaeuser Company||Attachment of superabsorbent materials to fibers using oil|
|US20050112979 *||24 Nov 2003||26 May 2005||Sawyer Lawrence H.||Integrally formed absorbent materials, products incorporating same, and methods of making same|
|US20050133180 *||19 Dic 2003||23 Jun 2005||Hugh West||Densification agent and oil treated cellulose fibers|
|US20050178518 *||13 Feb 2004||18 Ago 2005||Hugh West||Sodium sulfate treated pulp|
|US20060010663 *||18 Jul 2005||19 Ene 2006||Andrew Szypka||Absorbent sleeve to enclose a limb and absorb seepage from a cadaver|
|DE3719069A1 *||6 Jun 1987||15 Dic 1988||Ver Papierwerke Ag||Nappy pants|
|WO1982003324A1 *||10 Mar 1982||14 Oct 1982||Mitchell James G||Absorbent pads,incontinence care products and methods of production|
|Clasificación de EE.UU.||604/368, 428/510, 604/369, 604/378, 604/376, 428/87, 604/377, 428/479.3|
|Clasificación internacional||A61F13/15, A61L15/60|
|Clasificación cooperativa||A61F13/8405, A61F13/53747, A61F2013/53721, A61F2013/530481, A61L15/60, A61F13/534, A61F2013/53051, A61F2013/53445|
|Clasificación europea||A61F13/534, A61F13/537C2, A61L15/60|