Water-absorbent resin and production process
First Claim
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1. A water-absorbent resin comprising carboxyl-containing polymer particles having an average particle diameter of 100-600 μ
- m and a particle diameter distribution logarithmic standard deviation of 0.35 or less, and wherein the surface of the polymer particles is selectively crosslinked.
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Abstract
Water-absorbent resins having an average particle diameter of 100 to 600 μm and a particle diameter distribution of 0.35 or less are prepared by polymerizing an aqueous solution of a water-soluble ethylenically unsaturated monomer, pulverizing and sieving the gel-like polymer so obtained, and crosslinking the surface of the polymer powder. In an alternative process, an aqueous solution of the monomer having a viscosity greater than 15 cps is dispersed in a hydrophobic organic solvent and polymerized to obtain a polymer powder, and the surface of the polymer powder is crosslinked.
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6 Claims
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1. A water-absorbent resin comprising carboxyl-containing polymer particles having an average particle diameter of 100-600 μ
- m and a particle diameter distribution logarithmic standard deviation of 0.35 or less, and wherein the surface of the polymer particles is selectively crosslinked.
- 2. A water-absorbent resin comprising carboxyl-containing polymer particles having an angle-free, non-spherical shape and a ratio between length and breadth in the range of 1.5-20, and wherein the surface of the polymer particles is selectively crosslinked.
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4. A water-absorbent resin comprising carboxyl-containing polymer particles having an average particle diameter of 100-600 μ
- m and a particle diameter distribution logarithmic standard deviation of 0.35 or less, and wherein the surface of the polymer particles is further crosslinked.
- 5. A water-absorbent resin comprising carboxyl-containing particles having an angle-free, non-spherical shape and a ratio between length and breadth in the range of 1.5-20, and wherein the surface of the polymer particles is further crosslinked.
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