The present invention relates to coated polymer particles comprising a water-swellable polymer core and an essentially continuous coating encapsulating the core. The coating comprises an oxide, hydroxide or oxide hydrate of silicon, aluminum, zirconium, tin or titanium. The polymer particles do not show instantaneous swelling, when contacted with water or a water-containing liquid, but show delayed water absorption after an appropriate period of time. The coated polymer particles may be used in oil fields, in mining, for construction chemical compositions or as carrier for active substances. The coated polymer particles are prepared by a suspension coating process or a fluidized bed coating process.

Provided are a superabsorbent polymer and a preparation method thereof. According to the present invention, a superabsorbent polymer having high centrifuge retention capacity and absorption rate may be prepared by using a specific foam stabilizer.

The present invention addresses the problem of reducing the undried residue when recycling a fine powder of water-absorbing resin. The present invention is a method for producing a water-absorbing resin, wherein: a fine powder recycling step includes vi-1) a granulation step for obtaining a granulated gel, vi-2) a granulated gel addition step, and vi-3) a gel mixing step; the solids content of the granulated gel in the granulated gel addition step is 50-90% by mass; and the temperature of the granulated gel and the temperature of the water-containing gel-like crosslinked polymer is 50-100° C.

This provides a flexible, porous, dissolvable solid sheet article having large pores on its top surface as well as a method of making the same.

The present invention relates to a super-absorbent polymer having excellent properties, both centrifugal retention capacity (CRC) and absorption under pressure (AUP) having been improved by introducing a surface crosslinked layer crosslinked by surface-modified inorganic particles, and to a method for preparing the same. The super-absorbent polymer comprises: a base resin powder containing a crosslinked polymer of water-soluble ethylene-based unsaturated monomers having an at least partially neutralized acidic group; and a surface crosslinked layer formed on the base resin powder, wherein inorganic particles may be chemically bound to the crosslinked polymer contained in the surface crosslinked layer, via an oxygen-containing bond or a nitrogen-containing bond.

When a polymer gel has excellent mechanical strength and an ability to maintain surface wetness for a longer time, the polymer gel may be very widely applied to a variety of fields. The present disclosure provides example embodiments of a polymer gel having excellent mechanical strength and an ability to maintain surface wetness for a longer time. Further, the present disclosure provides example embodiments of a method of preparing the polymer gel.

A super absorbent polymer according to the present invention has excellent dryness while maintaining excellent absorption performance, and thus is preferably used for hygienic materials such as diapers, and can exhibit excellent performance.

Provided is a sandbag which is unlikely to break down even when using water-absorbing resin particles therein. A sandbag having a water-permeable bag and water-absorbing resin particles stored in the bag, wherein the pure-water absorption factor of the water-absorbing resin particles is at least a factor of 1,000, and the compression-breaking stress of the water-absorbing resin particles when swollen with pure water is at least 0.1N.

The present invention addresses the problem of providing; a water absorbent resin powder having a reduced amount of fine powder generated and a reduced amount of fine powder recovered; and a production method for the water absorbent resin. The production method of the present invention includes a drying step and a fine powder granulation step. The drying step is for obtaining a dried polymer by drying a particulate water-containing gel crosslinked polymer which is obtained using an acid group-containing unsaturated monomer as a main component. The fine powder granulation step is for obtaining a fine powder granulated product by adding a binder and an adhesion control agent to a fine powder made of a water absorbent resin. In this production method, the obtained fine powder granulated product is recovered in the drying step or in any step before the drying step.

A method is provided for recovering pulp fibers having little damage from a used absorbent article that contains pulp fibers and a superabsorbent polymer. The used absorbent article is treated at a temperature of greater than or equal to 80 C. with an organic acid aqueous solution having a pH no greater than 2.5, and the superabsorbent polymer is deactivated. Preferably, the pulp fibers and the deactivated superabsorbent polymer are separated from the used absorbent article after treatment with the organic acid aqueous solution, and further, a mixture including the separated pulp fibers and deactivated superabsorbent polymer is treated with an oxidizing agent, the deactivated superabsorbent polymer is decomposed, reduced in molecular weight and solubilized.