Superabsorbent Polymer and Preparation Method Thereof

Patent metadata

Field	Value
Publication number	US-2021008521-A1
Application number	US-201916968771-A
Country	US
Kind code	A1
Filing date	Nov 7, 2019
Priority date	Dec 11, 2018
Publication date	Jan 14, 2021
Grant date	—

Abstract

Provided is a method of preparing a superabsorbent polymer. More particularly, provided is a method of preparing a superabsorbent polymer, the method capable of preparing the superabsorbent polymer maintaining excellent basic absorption performances such as centrifugal retention capacity, absorbency under load, etc. while also exhibiting an improved absorption rate.

First claim

1 . A method of preparing a superabsorbent polymer, the method comprising:
a) mixing a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator to prepare a monomer composition; b) polymerizing the monomer composition to prepare a water-containing gel polymer; c) chopping the water-containing gel polymer; d) adding one or more fibers of a fluff pulp and a synthetic polymeric fiber to the chopped water-containing gel polymer and mixing them with each other to prepare a mixture; e) chopping the mixture; f) drying the mixture; and g) pulverizing the mixture.

2 . The method of preparing a superabsorbent polymer of claim 1 , wherein the fiber is included in an amount of 1 part by weight to 18 parts by weight with respect to 100 parts by weight of the water-containing gel polymer.

3 . The method of preparing a superabsorbent polymer of claim 1 , wherein the fiber has a length of 1 mm to 20 mm.

4 . The method of preparing a superabsorbent polymer of claim 1 , wherein the fiber has a width of 1 μm to 100 μm.

5 . The method of preparing a superabsorbent polymer of claim 1 , wherein water is further added in one or more of c) to e).

6 . The method of preparing a superabsorbent polymer of claim 5 , wherein the water is added in an amount of 1 part by weight to 20 parts by weight with respect to 100 parts by weight of the water-containing gel polymer.

7 . The method of preparing a superabsorbent polymer of claim 1 , wherein the monomer composition further includes a foaming agent.

8 . The method of preparing a superabsorbent polymer of claim 7 , wherein the monomer composition further includes one or more foam stabilizers selected from the group consisting of alkyl sulfate salts, alkyl sulfonate salts, alkyl phosphate salts, alkyl carbonate salts, polyethylene glycol alkyl ester, polypropylene glycol alkyl ester, glucoside alkyl ester, glycerol alkyl ester, and block-copolymers of polyethylene glycol and polypropylene glycol.

9 . The method of preparing a superabsorbent polymer of claim 1 , further comprising, after g),
h) adding a surface crosslinking agent to the mixture obtained in the step g); and i) performing a surface crosslinking reaction.

10 . The method of preparing a superabsorbent polymer of claim 9 , wherein the surface crosslinking agent is one or more selected from the group consisting of a polyhydric alcohol compound; an epoxy compound; a polyamine compound; a haloepoxy compound; a condensation product of a haloepoxy compound; an oxazoline compound; a mono-, di-, or polyoxazolidinone compound; a cyclic urea compound; a polyvalent metal salt; and an alkylene carbonate compound.

11 . The method of preparing a superabsorbent polymer of claim 9 , wherein the surface crosslinking agent is added in an amount of 0.001 part by weight to 5 parts by weight with respect to 100 parts by weight of the mixture.

12 . A superabsorbent polymer prepared by the preparation method of claim 1 .

13 . A superabsorbent polymer comprising a base polymer particle including a crosslinked polymer which is obtained by crosslinking polymerization of a water-soluble ethylenically unsaturated monomer in the presence of an internal crosslinking agent, and one or more fibers of a fluff pulp and a synthetic polymeric fiber; and
a surface-crosslinked layer which is formed on the surface of the base polymer particle, and is obtained by additionally crosslinking the crosslinked polymer via a surface crosslinking agent, wherein at least a portion of the fibers is incorporated into an interior of the base polymer particle.

14 . The superabsorbent polymer of claim 13 , wherein the superabsorbent polymer has centrifugal retention capacity (CRC) of 25 g/g to 45 g/g, as measured in accordance with EDANA method WSP 241.3.

15 . The superabsorbent polymer of claim 13 , wherein the superabsorbent polymer has absorbency under load (AUL) at 0.3 psi of 25 g/g to 40 g/g, as measured in accordance with EDANA method WSP 242.3.

16 . A superabsorbent polymer composition comprising:
a superabsorbent polymer particle; and one or more fibers of a fluff pulp and a synthetic polymeric fiber, wherein at least a portion of the fibers is incorporated into an interior of the superabsorbent polymer particle.

Assignees

• Lg Chemical Ltd

Inventors

• Choi Yong Seok
• Hong Yeon Woo
• Shin Eunji
• Ahn Taebin

Classifications

• B29B9/12

  characterised by structure or composition · CPC title

• C08L33/02

  Homopolymers or copolymers of acids; Metal or ammonium salts thereof · CPC title

• C08J3/245 Primary

  Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking · CPC title

• C08F20/06

  Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof · CPC title

• C08L97/02

  Lignocellulosic material, e.g. wood, straw or bagasse {(manufacture of articles made from lignocellulosic material by dry processes B27N)} · CPC title