The present invention provides a method for producing water-absorbent resin particles which show an excellent water absorption rate and high equilibrium swelling capacity and which have an appropriate particle size to be excellent in handleability, and water-absorbent resin particles obtained by the method. The present invention is a method for producing water-absorbent resin particles by reversed phase suspension polymerization of a water-soluble ethylenically unsaturated monomer, the method including the steps of: (A) first reversed phase suspension polymerization of a water-soluble ethylenically unsaturated monomer in a petroleum hydrocarbon dispersion medium using a water-soluble radical polymerization initiator, in the absence of an internal crosslinking agent and in the presence of a surfactant having an HLB of 8 to 12; (B) intermediate crosslinking reaction by adding an intermediate crosslinking agent; (C) second reversed phase suspension polymerization of a water-soluble ethylenically unsaturated monomer added to the petroleum hydrocarbon dispersion medium containing the surfactant dissolved therein using a water-soluble radical polymerization initiator in the absence of an internal crosslinking agent, thereby producing a water-absorbent resin precursor; and (D) post crosslinking reaction of the water-absorbent resin precursor preliminary adjusted to have a moisture content of 30 to 100% by mass relative to a water-soluble ethylenically unsaturated monomer component in the water-absorbent resin precursor.

Claims

6 · 1 independent · depth 3

6 granted claims

›1.independentA method for producing water-absorbent resin particles by reversed phase suspension polymerization of a water-soluble ethylenically unsaturated monome…+5

Classifications

6 codes

IPC · International Patent Classification

Section B — Performing operations; transporting

B32B5/16

USPC · US Patent Classification

428/402525/319526/348526/235526/230

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Pendency

4.0 y

1,469 days filing → grant

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Examiner

Leszek Kiliman

art unit 1788 · TC 1700

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Citations: 25 back · 0 forward

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1 priority documents

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Type	Document	Date
related publication	US 20130260151 A1	3 Oct 2013

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