Patent ID: 8288002
Filing Date: 2012-10-16
Classification: A61L,Y10T

Abstract:
1. Water-absorbing polymer particles comprising: (a) from about 0.1 wt. % to about 99.999 wt. % of a polymerized, ethylenically unsaturated, acidic group-containing monomers or salts thereof, or polymerized, ethylenically unsaturated monomers containing a protonated or a quaternary nitrogen, or mixtures thereof, wherein mixtures comprising at least ethylenically unsaturated, acidic groups-containing monomers; (b) from about 0.001 wt. % to about 5 wt. % of one or more cross-linkers; wherein elements a) and b) are polymerized and prepared into water-absorbing polymer particles; and wherein the water-absorbing polymer particles further comprise the following surface additives; and (c) from about 0.01 to 5 percent by weight of the water-absorbing polymer of a secondary crosslinker; and (d) from about 0.001 to 0.3 percent by weight of the water-absorbing polymer of a thermoplastic polymer having a number average molecular weight from about 10,000 g/mol to about 1,000,000 g/mol and having a melting temperature of at least 50° C.; wherein said thermoplastic polymer is selected from thermoplastic polyurethanes, thermoplastic polyesters, thermoplastic polyamides, thermoplastic polyolefins, thermoplastic polyvinyl esters, thermoplastic polymers based on styrene, polystyrenes, polyimides, sulfur polymers, fluoride plastics, styrene-olefin copolymers, polyacrylates or ethylene-vinyl acetate copolymers or mixtures of two or more of these polymers wherein the water-absorbing polymer particles comprise from about 80 to about 99.99 percent by weight of the polymer of water-absorbing polymer particles having a particle size from about 200 μm to about 850 μm and from about 0.01 wt % to about 20 wt % of superabsorbent polymer fine particles having a particle size of less than about 200 μm wherein the superabsorbent polymer fine particles are bound to the surface of the water-absorbing polymer particle by the thermoplastic polymer and wherein water-absorbing polymer particles surface treated with elements c) and d) are heat treated to a temperature of from about 150° C. to about 200° C. in order to carry out the secondary crosslinking of the surface of the water-absorbing polymer particles and to melt the thermoplastic polymer in order to bind the fine particles to the surface of the water-absorbing polymer particles.