Method for producing water-absorbent resin particles and water-absorbent resin particles
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United States of America Patent
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Feb 10, 2015
Grant Date -
Oct 3, 2013
app pub date -
Nov 24, 2010
filing date -
Nov 24, 2010
priority date (Note) -
Withdrawn
status (Latency Note)
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Abstract
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.
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International Classification(s)
- 2010 Application Filing Year
- B32B Class
- 4989 Applications Filed
- 2308 Patents Issued To-Date
- 46.27 % Issued To-Date
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- B32B Class
- 0 % this patent is cited more than
- 11 Age
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| 11.5 Year Payment | $7400.00 | $3700.00 | $1850.00 | Jun 2, 2026 |