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Super absorbent polymer and method for preparing the same

  • US 10,450,425 B2
  • Filed: 11/11/2015
  • Issued: 10/22/2019
  • Est. Priority Date: 11/24/2014
  • Status: Active Grant
First Claim
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1. A method of preparing a superabsorbent polymer comprising:

  • 1) carrying out thermal polymerization or photopolymerization of a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator to form a hydrous gel phase polymer;

    2) passing the hydrous gel phase polymer through a chopper die and pulverizing the polymer;

    3) drying the pulverized hydrous gel phase polymer;

    4) pulverizing the dried polymer; and

    5) surface-crosslinking the pulverized polymer,wherein the chopper die is provided with a plurality of non-circular holes,the chopper die has an opening/ closing rate of 30 to 40%, andthe chopper die satisfies the following Mathematical Formula 1;


    c>





    {square root over (0.4×

    π

    ×



    A
    )} 



    [Mathematical Formula 1]whereinA is the overall area of the upper surface of the chopper die with a unit mm2, n is the number of holes, and c is the total circumference of the plurality of holes, andwherein the value of c is 500 to 800 mm.

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