Title:
METHOD FOR PRODUCING WATER-ABSORBENT RESIN PARTICLES AND WATER-ABSORBENT RESIN PARTICLES
Document Type and Number:
WIPO Patent Application WO/2012/053121
Kind Code:
A1
Abstract:
Provided are: a method for producing water-absorbent resin particles which have excellent water absorption speed and high equilibrium swelling performance as well as a reasonable particle size and good handleability; and water-absorbent resin particles obtained therefrom. The present invention is a method for producing water-absorbent resin particles by subjecting a water-soluble ethylenically unsaturated monomer to a reverse phase suspension polymerization, comprising: (A) a step of subjecting the water-soluble ethylenically unsaturated monomer to a first reverse phase suspension polymerization in the absence of an internal crosslinking agent, in the presence of a surfactant with an HLB of 8-12, and in a petroleum hydrocarbon dispersion medium by using a water-soluble radical polymerization initiator; (B) a step of conducting an intermediate crosslinking reaction by further adding an intermediate crosslinking agent; (C) a step of producing a water-absorbent resin precursor by adding the water-soluble ethylenically unsaturated monomer while the surfactant is dissolved in the petroleum hydrocarbon dispersion medium, and by performing a second reverse phase suspension polymerization in the absence of the internal crosslinking agent by using the water-soluble radical polymerization initiator; and (D) a step of conducting a post-crosslinking reaction after adjusting the moisture content of the water-absorbent resin precursor to 30-100 mass% relative to the water-soluble ethylenically unsaturated monomer component which constitutes the water-absorbent resin precursor.
Inventors:
HEGURI ATSUSHI (JP)
TANIMURA KENJI (JP)
ONODA YUICHI (JP)
TANIMURA KENJI (JP)
ONODA YUICHI (JP)
Application Number:
PCT/JP2010/070905
Publication Date:
April 26, 2012
Filing Date:
November 24, 2010
Export Citation:
Assignee:
SUMITOMO SEIKA CHEMICALS (JP)
HEGURI ATSUSHI (JP)
TANIMURA KENJI (JP)
ONODA YUICHI (JP)
HEGURI ATSUSHI (JP)
TANIMURA KENJI (JP)
ONODA YUICHI (JP)
International Classes:
C08F2/32
Domestic Patent References:
| WO2009096268A1 | 2009-08-06 | |||
| WO2009025235A1 | 2009-02-26 | |||
| WO2007004529A1 | 2007-01-11 | |||
| WO2004083284A1 | 2004-09-30 |
Foreign References:
| JP2009132755A | 2009-06-18 | |||
| JP2006342306A | 2006-12-21 | |||
| JP2006131767A | 2006-05-25 | |||
| JPH11279207A | 1999-10-12 | |||
| JPH0912613A | 1997-01-14 | |||
| JPH03227301A | 1991-10-08 |
Other References:
See also references of EP 2631251A4
Attorney, Agent or Firm:
YASUTOMI & Associates (JP)
Patent business corporation Yasutomi international patent firm (JP)
Patent business corporation Yasutomi international patent firm (JP)
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Claims: