Method for production of hydrophilic resin
AssigneeNippon Shokubai Co., Ltd.
InventorsYoshio Irie, Katsuhiro Kajikawa, Kunihiko Ishizaki, Takumi Hatsuda
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Abstract
In the production of an acrylate polymer by the steps of preparing a water-soluble unsaturated monomer having a ratio of neutralization in the range of 30 to 100 mol % and containing 50 to 100 mol % of an acrylate and then polymerizing the monomer, a method for the production of a hydrophilic resin which comprises using a water-soluble unsaturated monomer having a β-hydroxy propionic acid (salt) content of not more than 1,000 ppm. The hydrophilic resin obtained by this method exhibits excellent physical properties and has only a small residual monomer content. Further, a residual monomer content neither occurs nor increases in any using conditions.
Claims14
A method for the production of an absorbent resin having a cross-linked structure which comprises preparing a mixture solution of a water-soluble unsaturated monomer or monomer mixture containing 50 mol % or greater of acrylic acid which has been partially neutralized or completely neutralized in an amount of 30 to 100 mol % to form alkali metal and/or ammonium salts, 1 to 1,000 ppm of β-hydroxy propionic acid or a salt thereof and a first cross-linking agent, polymerizing the mixture solutions drying the gel polymer thus obtained by heating at a temperature of not less than 130° C., and optionally pulverizing and/or granulating to obtain powdered absorbent resin.
A method for the production of a hydrophilic resin which comprises polymerizing a water-soluble unsaturated monomer or monomer mixture containing 50 mol % or greater of acrylic acid which has been neutralized in an amount of 30 to 100 mol % to form at least a sodium or potassium salt, 1 to 1000 ppm of β-hydroxy propionic acid or a salt thereof and optionally a first cross-linking agent, and said water-soluble unsaturated monomer is polymerized within 24 hours after preparation, and drying the gel polymer by heating at a temperature of at least 130° C.
Dependencies are inferred from the claim text.