Stock material or miscellaneous articles – Coated or structually defined flake – particle – cell – strand,... – Rod – strand – filament or fiber
Patent
1997-08-20
2000-04-18
Nutter, Nathan M.
Stock material or miscellaneous articles
Coated or structually defined flake, particle, cell, strand,...
Rod, strand, filament or fiber
428393, 428394, 428396, 442 60, 442 61, 442 62, 442 64, 442 70, 442 72, 442 76, 442117, 442164, 442166, 442167, 442 63, 604304, 604365, 604366, 604367, 604372, 604374, 604377, 604378, 47 101R, 52319, 53111RC, 239 34, 239 44, A61L 1560, C08J 518, B32B 518
Patent
active
060513179
DESCRIPTION:
BRIEF SUMMARY
The invention relates to sheet-like absorbents for water and aqueous solutions, a process for the production of said sheet-like absorbents, and their use.
Sheet-like absorbents present the possibility of fixing superabsorbent polymers (SAP) in the form of a powder or granulate in any desired arrangement in/on one or multiple sheets. Said fixation is then carried out in the optimum form for later use, such as in diapers for babies, adult incontinence articles, cable sheathings, soil conditioners, packaging inserts in the food industry, for animal hygiene, wound dressings, and cloths.
For later use, in order to achieve optimum distribution of a powdered superabsorbent polymer and to fix same, various methods have been described.
EP 212,618 B1 describes diaper constructions wherein polymerizates having a specific grain size distribution are distributed in a cellulose fiber layer. However, such a construction is insufficiently stable with respect to the distribution of the superabsorbent polymer; in particular, the distribution of the SAP may be altered undesirably during transportation, resulting in non-uniform absorption, e.g., in a diaper.
Another method of fixing powdered superabsorbent polymers in a specific arrangement is described in EP 425,269 A2, according to which the SAPs are bound to thermoplastic, water-insoluble fibers. Binding the SAP to the fiber is effected in such a way that a slightly surface-melted fiber is contacted with the powdered superabsorbent polymer. The fibers themselves are fixed among one another in the same manner. The disadvantage of this process is that the absorptive capacity of the powdered superabsorbent polymer is not utilized in full extent. Part of the SAP is covered by the thermoplastic and thus not reached by water or aqueous solutions.
EP 547,474 A1 describes a process for the production of absorbing materials wherein superabsorbent polymers are distributed. The absorptive capacity of the absorbing materials thus obtained is lower than the ratio of SAP incorporated in these materials would suggest, i.e., part of the SAP is blocked as a result of the selection of materials used and the production process employed. Moreover, the type of matrix material used is limited in that the melting point of this material must be above the decomposition temperature of the SAP.
EP 303,445 A1 describes an absorbent sheet material wherein a water-containing SAP has been fixed on a support. The use of this structure is limited to a patch used as drug reservoir.
JP Application No. 75-85462 describes a method of producing superabsorbent sheets made of a starch/graft polymer integrated in a water-soluble, film-forming polymer.
As an indispensable third component, this document mentions a material serving as base material. The superabsorbent polymer is fixed on said base material together with the soluble, film-forming polymer.
EP 604,730 A1 describes SAP-containing structures which decompose in water. In addition to the SAP, dispersible polymers and plasticizers are mentioned as indispensable components. The structures manufactured according to this application do by no means meet the demand for a defined arrangement of a superabsorber in a matrix, because the methods described in this document, such as extrusion, mixing or blending, are absolutely unsuitable for this purpose.
After disintegration of the described sheet materials, particles remain in addition to the superabsorber; consequently, the matrix material is not soluble in water.
It is therefore the object of the present invention to provide a superabsorbent sheet having a defined arrangement of superabsorbent polymers at full utilization of the swelling capacity of the superabsorbent polymers, i.e., without loss of absorptive capacity.
It is another object of the invention to find production processes according to which such a sheet can be manufactured in an uncomplicated and cost-effective way. In addition, the sheet should not be fixed to a substrate, as described in the Japanese patent application No. 75-85462, so that such a
REFERENCES:
patent: 4335722 (1982-06-01), Jackson
patent: 5246770 (1993-09-01), Bottiglione et al.
patent: 5589256 (1996-12-01), Hansen et al.
patent: 5693411 (1997-12-01), Hansen et al.
Brueggemann Helmut
Dahmen Kurt
Lehwald Dieter
Theilmann Roland
Nutter Nathan M.
Stockhausen GmbH & Co. KG
LandOfFree
Sheet-like superabsorbent structures does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Sheet-like superabsorbent structures, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Sheet-like superabsorbent structures will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2334903