WATER-ABSORBENT RESIN MANUFACTURING METHOD AND LIQUID PERMEABILITY IMPROVEMENT METHOD
First Claim
1. A method for the production of a water-absorbing resin which comprises:
- a polymerization step for polymerizing an aqueous solution of acrylic acid (or salt thereof) to obtain a hydrogel cross-linked polymer;
a drying step for drying said hydrogel cross-linked polymer to obtain a water-absorbing resin powder;
a classification step for classifying said water-absorbing resin powder; and
a surface cross-linking step for surface cross-linking said water-absorbing resin powder before or after the classification step;
wherein electricity is eliminated in the classification step.
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Abstract
A method for the production of a water-absorbing resin is to be provided which permits enhancement and stabilization of property, for example, liquid permeability, of a water-absorbing resin by a simple and convenient method without requiring change of raw materials or expensive facility investment. The method comprises a polymerization step for polymerizing an aqueous solution of acrylic acid (or salt thereof) to obtain a hydrogel cross-linked polymer; a drying step for drying the hydrogel cross-linked polymer to obtain a water-absorbing resin powder; a classification step for classifying the water-absorbing resin powder; and a surface cross-linking step for surface cross-linking the water-absorbing resin powder before or after the classification step, wherein electricity is eliminated in the classification step.
55 Citations
23 Claims
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1. A method for the production of a water-absorbing resin which comprises:
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a polymerization step for polymerizing an aqueous solution of acrylic acid (or salt thereof) to obtain a hydrogel cross-linked polymer; a drying step for drying said hydrogel cross-linked polymer to obtain a water-absorbing resin powder; a classification step for classifying said water-absorbing resin powder; and a surface cross-linking step for surface cross-linking said water-absorbing resin powder before or after the classification step; wherein electricity is eliminated in the classification step. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method for enhancing liquid permeability of a water-absorbing resin which comprises:
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a polymerization step for polymerizing an aqueous solution of acrylic acid (or salt thereof) to obtain a hydrogel cross-linked polymer; a drying step for drying said hydrogel cross-linked polymer to obtain a water-absorbing resin powder; a classification step for classifying said water-absorbing resin powder; and a surface cross-linking step for surface cross-linking said water-absorbing resin powder before or after the classification step; wherein electricity is eliminated in the classification step. - View Dependent Claims (23)
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Specification