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US 5,668,078 AGranted
Water-absorbent resin particles and the production thereof
AssigneeSanyo Chemical Industries, Ltd.
InventorsTakashi Sumiya, Masanori Koike, Kenji Tanaka
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AssigneeSanyo Chemical Industries, Ltd.
InventorsTakashi Sumiya, Masanori Koike, Kenji Tanaka
Estimating the term…
The present invention relates to a process for producing improved water-absorbent resin particles comprising the step of treating water-absorbent particles, which are crosslinked polymers of ethylenically unsaturated monomers comprising acrylic acid and/or acrylic acid salt as an essential element, with a modified silicone oil having a functional group which can react with a carboxyl group and/or a carboxylate group in the molecule Improved water-absorbent resin particles obtained by the process have a hygroscopic blocking rate of 20 % or less under a relative humidity of 80 % at 40.degree. C., a dust level of 10 CPM or less and an absorbing characteristic of initial absorbency under load to physiological saline of 20 times or more. The present invention provides water-absorbent resin particles which have an improved hygroscopic blocking rate under high humidity and dust generation rate with a good initial absorbency under load and absorbing capacity.
A process for producing water-absorbent resin particles comprising the step of reacting substantially water-insoluble water-absorbent resin particles with a modified silicone oil, the particles comprising crosslinked polymers of ethylenically unsaturated monomers that comprise acrylic acid and/or acrylic acid salt as an essential element and having an average particle size of 200-600 .mu.m, said modified silicone oil having a functional group capable of reacting with a carboxyl group and/or a carboxylate group in the molecule and having a molecular weight of approximately 1,000-1,000,000 and a viscosity of 10-20,000 cst at 25.degree. C.
Dependencies are inferred from the claim text.