A method of making superabsorbent polymer material and comprising the step of providing soluble polyacrylic acid polymers. The soluble polyacrylic acid polymers have a molar percent of carbon-to-carbon double bonds of at least 0.03. The soluble polyacrylic acid polymers may be obtained from pre-existing recycled post-consumer superabsorbent polymer material, and/or from pre-existing recycled post-industrial superabsorbent polymer material. Superabsorbent polymer material obtained by the method, and absorbent articles comprising these materials are also provided.

Poly(acrylic acid)-based superabsorbent polymer (SAP) in a feed stream is converted into poly(acrylic acid) (PAA) in a hydrothermal treatment (HTT) reactor. The total energy used to degrade the SAP into PAA is less than about 50 MJ/kg SAP.

Superabsorbent polymer material comprising cross-linked polyacrylic acid and salts thereof. The superabsorbent polymer material further comprising at least 3.0 weight-%, based on the total weight of the superabsorbent polymer material, of soluble polyacrylic acid polymers. A method for making such superabsorbent polymer materials is also disclosed.

The present invention provides a gel containing a water-absorbing crosslinked polymer, and a condensate of a reactive silicon compound having at least one selected from the group consisting of an acidic dissociative group, an acidic dissociative group in a salt form, and a derivative group of an acidic dissociative group.

Disclosed is water-absorbent resin particles including a crosslinked polymer having a structural unit derived from an ethylenically unsaturated monomer including at least one compound selected from the group consisting of (meth)acrylic acid and a salt thereof, in which a proportion of (meth)acrylic acid and a salt thereof is 70 to 100 mol % with respect to a total amount of monomer units in the crosslinked polymer, and a dissolved content in an aqueous solution of 0.9% by mass NaCl at 25° C. is 10% by mass or more and 25% by mass or less, and a dissolved content in an aqueous solution of 0.9% by mass NaCl at 40° C. is 1.4% by mass or more and 30% by mass or less, where the dissolved contents are measured by a specific method.

Water-absorbing resin particles are disposed, the water-absorbing resin particles including: a polymer particle containing a crosslinked polymer having a monomer unit derived from an ethylenically unsaturated monomer including at least one kind of compound selected from the group consisting of (meth)acrylic acid and a salt thereof; and a plurality of inorganic particles disposed on a surface of the polymer particle, in which a proportion of a (meth)acrylic acid and a salt thereof is 70 to 100 mol % with respect to a total amount of monomer units in the crosslinked polymer. In a case where a water absorption speed index I=(value of non-pressurization DW after 10 seconds)×6 [mL/g], and a water absorption speed index II=(value of non-pressurization DW after 3 minutes)/3 [mL/g], a static suction index α calculated by the following formula:

α=(I+II)/2

is 5.0 mL/g or higher.

Disclosed is water-absorbent resin particles including: a crosslinked polymer having a monomer unit derived from an ethylenically unsaturated monomer including at least one compound selected from the group consisting of (meth)acrylic acid and a salt thereof, in which a proportion of (meth)acrylic acid and a salt thereof is 70 to 100 mol % with respect to a total amount of monomer units in the crosslinked polymer, an artificial urine permeation speed when the water-absorbent resin particles are swollen tenfold is 1.0 g/min or more and 35.0 g/min or less, a water retention capacity for a physiological saline solution is 32 to 60 g/g, and a contact angle measured in a test performed in the order of i) and ii) is 70 degrees or smaller.

An absorbent article 100 includes an absorber 10, the absorber contains water-absorbent resin particles 10a, and in the water-absorbent resin particles 10a, a water absorption rate based on the Vortex method at 300 rpm is 10 to 50 seconds.

Disclosed is the water-absorbent resin particles including a crosslinked polymer having a structural unit derived from an ethylenically unsaturated monomer including at least one compound selected from the group consisting of (meth)acrylic acid and a salt thereof, in which a proportion of (meth)acrylic acid and a salt thereof is 70 to 100 mol % with respect to a total amount of monomer units in the crosslinked polymer, and a dissolved content is 10% by mass or more and 40% by mass or less, and a dissolved content when the water-absorbent resin particles are pulverized so that a median particle size is 80 to 165 μm is 15% by mass or more and 40% by mass or less, where the dissolved contents are measured by a specific method.

An absorbent article 100 includes an absorber 10, the absorber 10 contains water-absorbent resin particles 10a, in the water-absorbent resin particles 10a, a hardened bulk density is 0.500 g/cm.sup.3 or more, and an amount of change in the hardened bulk density at a time of moisture absorption at a temperature of 30° C. and a relative humidity of 80% for 1 hour is 0.020 g/cm.sup.3 or more.