PROCESS FOR PRODUCING WATER-ABSORBING RESIN

Title:

PROCESS FOR PRODUCING WATER-ABSORBING RESIN

Document Type and Number:

WIPO Patent Application WO/2012/132861

Kind Code:

A1

Abstract:

This process for producing a water-absorbing resin includes: a polymerization step of subjecting a polymerizable component which contains a water-soluble ethylenic unsaturated monomer dissolved in water to polymerization using a water-soluble azo radical polymerization initiator to form a reaction system which contains a water-absorbing resin precursor; and a dehydration step of removing water from the reaction system by heating. In the dehydration step, a water-soluble radical polymerization initiator is added to the reaction system in a first arbitrary dehydration stage such that the retention of water as calculated by formula (1) is 50% or more, and then a reducing substance is added to the reaction system in a second arbitrary dehydration stage such that the retention of water is lower than that in the first arbitrary dehydration stage by 10% or more. According to the process, a water-absorbing resin which exhibits a high water absorption can be produced while minimizing the content of residual monomers.

Inventors:

HONDA NORIKO (JP)
OMURA AYAKA (JP)
KONDO KIMIHIKO (JP)

Application Number:

PCT/JP2012/056300

Publication Date:

October 04, 2012

Filing Date:

March 12, 2012

Export Citation:

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Assignee:

SUMITOMO SEIKA CHEMICALS (JP)
HONDA NORIKO (JP)
OMURA AYAKA (JP)
KONDO KIMIHIKO (JP)

International Classes:

C08F6/24; C08F4/04; C08F4/28; C08F20/06

Foreign References:

JP2008133396A	2008-06-12
JP2002105125A	2002-04-10
JPS6462317A	1989-03-08
JP2003206305A	2003-07-22
JP2006176570A	2006-07-06
JP2008007567A	2008-01-17
JP2002241428A	2002-08-28
JP2006176570A	2006-07-06
JP2002105125A	2002-04-10
JPS6462317A	1989-03-08

Other References: