Superabsorbent polymers with fast absorption properties

Superabsorbent polymers with fast absorption properties

  • CN 104,974,312 B
  • Filed: 04/03/2015
  • Issued: 06/12/2020
  • Est. Priority Date: 04/07/2014
  • Status: Active Grant
First Claim
Patent Images

1. A process for the preparation of particulate superabsorbent polymers having fast water absorption properties comprising the steps of:

  • a) preparing an aqueous monomer solution of a mixture of polymerizable unsaturated acid group-containing monomers and internal crosslinking agent monomers, wherein the aqueous monomer solution contains dissolved oxygen;

    b) spraying the aqueous monomer solution of step a), comprising adding an inert gas to the aqueous monomer solution of step a) to replace dissolved oxygen in the aqueous monomer solution;

    c) polymerizing the aqueous monomer solution of step b), comprising the steps of;

    c1) adding the following to the aqueous monomer solution of step a);

    i) an aqueous solution containing from about 0.05 to about 2.0 wt.% of a blowing agent, based on the total amount of polymerizable unsaturated acid group containing monomer solution; and

    ii) an aqueous solution containing from about 0.001 to 1.0 weight percent of a mixture of a lipophilic surfactant and a polyethoxylated hydrophilic surfactant, based on the total amount of polymerizable unsaturated acid group-containing monomer solution;

    c2) subjecting the monomer solution of step c1) to a high shear mixing process to form a treated monomer solution, wherein components i) an aqueous solution containing about 0.1-1.0 wt.% of a blowing agent and ii) an aqueous solution containing about 0.001-1.0 wt.% of a mixture of a lipophilic surfactant and a polyethoxylated hydrophilic surfactant are added to the aqueous monomer solution after step b) of spraying the aqueous monomer solution and before step c2) of high shear mixing the aqueous monomer solution;

    c3) forming a hydrogel by adding a polymerization initiator to the treated monomer solution of step c2), wherein the initiator is added to the treated monomer solution after the blowing agent and surfactant mixture, wherein a polymer is formed to incorporate the bubbles of blowing agent into the polymer structure; and

    d) drying and grinding the hydrogel of step c) to form particulate superabsorbent polymer; and

    e) subjecting the particulate superabsorbent polymer of step d) to surface cross-linking with a surface cross-linking agent, wherein the surface cross-linked superabsorbent polymer has a vortex time of about 30-60 seconds.

View all claims
    ×
    ×

    Thank you for your feedback

    ×
    ×