The present disclosure relates to a method for preparing a super absorbent polymer. More specifically, it relates to a method for preparing a super absorbent polymer capable of preparing a super absorbent polymer in which the residual monomer content and the extractable content are simultaneously reduced by adding a reducing agent capable of a redox reaction with a thermal polymerization initiator before drying the hydrogel polymer.

Provided is a method for recycling a water-absorbing resin which contains absorbed liquid, with consideration for a resource aspect and an energy aspect. The method for recycling a water-absorbing resin which contains absorbed liquid includes: discharging the absorbed liquid from the water-absorbing resin which contains the absorbed liquid; and recovering a water-absorbing power of the water-absorbing resin.

[Problem] To provide a particulate water-absorbing agent that can significantly reduce re-wet even when pressure is applied to the particulate water-absorbing agent from the outside when the particulate water-absorbing agent is in a swollen state.

[Solution] A particulate water-absorbing agent comprising a surface-crosslinked polyacrylic acid (salt)-based water-absorbing resin as a main component and satisfying the following expression (1).

AAP(2.06 kPa)+RCAP(2.06 kPa)≥0.58×CRC+55.6  (1),

wherein AAP (2.06 kPa) represents absorption capacity (g/g) under a pressure of 2.06 kPa, RCAP (2.06 kPa) represents retention capacity against pressure after swelling (g/g), and CRC represents absorption capacity without pressure (g/g).

The present disclosure relates to methods for harvesting microalgae and to porous superabsorbent polymeric materials useful in such processes.

The present invention relates to a manufacturing method of a super absorbent polymer. The manufacturing method of a super absorbent polymer according to the present invention may include: carrying out a thermal polymerization or a photopolymerization of a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator to form a hydrogel polymer; drying the hydrogel polymer; pulverizing the dried polymer; classifying the pulverized polymer into a fine powder having a particle diameter of less than 150 μm and a polymer having a particle diameter of 150 to 850 μm according to the particle diameter; performing reassembly by mixing and wetting the fine powder with 5 to 30° C. water in a content of 50 to 200 parts by weight with respect to 100 parts by weight of the fine powder having a particle size of 150 μm or less, to form a fine powder reassembly; and mixing the polymer having a particle diameter of 150 to 850 μm with the fine powder reassembly, followed by surface cross-linking, and may obtain a super absorbent polymer having a high fine aggregation strength.

The present invention relates to an anti-stick processing aid for use in a process for producing water-absorbing polymers, comprising the steps of: i) mixing (α1) 0.1 to 99.999% by weight of polymerizable, ethylenically unsaturated monomers containing acid groups, or salts thereof, (α2) 0 to 70% by weight of monomers copolymerizable with (α1), (α3) 0.001 to 10% by weight of crosslinkers, (α4) 0 to 30% by weight of polymers, (α5) 0 to 80% by weight of water, and (α6) 0 to 20% by weight of assistants, (ii) free-radical polymerization with crosslinking to form a hydrogel polymer, (iii) drying the hydrogel polymer, (iv) grinding and sieving the hydrogel polymer, (v) surface postcrosslinking the hydrogel polymer and (vi) drying and finishing the water-absorbing polymer,
wherein the anti-stick processing aid is used before and/or in steps (iii).

The invention relates to a process for producing water-absorbing polymer particles with high free swell rate, comprising the steps of polymerization, drying, grinding, classification and thermal surface postcrosslinking, remoisturization and drying again.

The present invention relates to a superabsorbent polymer and a method for producing the same. The superabsorbent polymer includes a core layer polymerized with monomers having carboxylic group, a first shell layer formed from a surface crosslinking agent, and a second shell layer formed from zingiberaceae extracts. By a surface modification on the first shell layer performed from a specific amount of the zingiberaceae extracts, the superabsorbent polymer produced according to the method for producing the same has a good antimicrobial property and deodorizing effects, and retains an original absorbent property.

A particulate water-absorbent resin composition is provided which can suppress the odor of trimethylamine in addition to the odor of acetaldehyde, in other words, which can simultaneously suppress complex odors. In this particulate water-absorbent resin composition, which contains a hydrazide compound support and a particulate water-absorbent resin, the median particle diameter of the particulate water-absorbent resin is 100-600 m.

The present invention provides a water absorbent resin composition which suppresses acetaldehyde odor, while being suppressed in coloring with time. A water absorbent resin composition which contains a hydrazide compound carrier and a water absorbent resin, wherein: the degree of yellowing is 10 or less if 2.0 g of this water absorbent resin composition is held at a temperature of 70° C. at a relative humidity of 90% for 7 days; and if 10.0 g of this water absorbent resin composition and 900 ml of a nitrogen gas having an acetaldehyde concentration of 20 ppm are sealed in a hermetically sealed bag having a volumetric capacity of 2 liters, the acetaldehyde concentration of the gas in the hermetically sealed hag measured after a lapse of one hour is 15 ppm or less.