Method for preparing super absorbent resin

Patent metadata

Field	Value
Publication number	US-2016271584-A1
Application number	US-201414907470-A
Country	US
Kind code	A1
Filing date	Dec 3, 2014
Priority date	Dec 3, 2013
Publication date	Sep 22, 2016
Grant date	—

Abstract

Disclosed is a method of preparing a superabsorbent polymer, including a) subjecting a monomer composition composed of a water-soluble ethylenic unsaturated monomer and a polymerization initiator to thermal polymerization or photopolymerization, thus preparing a hydrous gel polymer, b) drying the hydrous gel polymer, c) grinding the dried hydrous gel polymer, d) adding the ground hydrous gel polymer with particles having i) a BET specific surface area of 300 to 1500 m 2 /g and ii) a porosity of 50% or more and with a surface crosslinking agent, and e) performing a surface crosslinking reaction.

First claim

1 . A method of preparing a superabsorbent polymer, comprising:
a) subjecting a monomer composition comprising a water-soluble ethylenic unsaturated monomer and a polymerization initiator to thermal polymerization or photopolymerization, thus preparing a hydrous gel polymer; b) drying the hydrous gel polymer; c) grinding the dried hydrous gel polymer; d) adding the ground hydrous gel polymer with particles having i) a BET specific surface area of 300 to 1500 m 2 /g and ii) a porosity of 50% or more and with a surface crosslinking agent; and e) performing a surface crosslinking reaction.

2 . The method of claim 1 , wherein the particles have a particle size ranging from 2 nm to 50 μm.

3 . The method of claim 1 , wherein the particles have superhydrophobicity with a water contact angle of 125° or more.

4 . The method of claim 1 , wherein the particles have a particle size ranging from 2 nm to 50 μm and superhydrophobicity with a water contact angle of 125° or more.

5 . The method of claim 1 , wherein the particles have a BET specific surface area of 500 to 1500 m 2 /g.

6 . (canceled)

7 . The method of claim 3 , wherein the particles have superhydrophobicity with a water contact angle of 140° or more.

8 . The method of claim 3 , wherein the particles have superhydrophobicity with a water contact angle of 145° or more.

9 . The method of claim 1 , wherein the particles have a porosity of 90% or more.

10 . The method of claim 1 , wherein the particles are used in an amount of 0.001 to 1 parts by weight based on 100 parts by weight of the superabsorbent polymer.

11 . The method of claim 1 , wherein the particles comprise at least one selected from the group consisting of silica, alumina, carbon, and titania (TiO 2 ).

12 . The method of claim 1 , further comprising grinding the hydrous gel polymer to a particle size ranging from 1 to 15 mm, before the drying in b).

13 . The method of claim 1 , wherein the drying in b) is performed at a temperature ranging from 150 to 250° C.

14 . The method of claim 1 , wherein the grinding in c) comprises grinding the hydrous gel polymer to a particle size ranging from 150 to 850 μm.

15 . The method of claim 1 , wherein the surface crosslinking agent in d) comprises any one or more selected from the group consisting of a polyhydric alcohol compound, an epoxy compound, a polyamine compound, a haloepoxy compound, a haloepoxy compound condensed product, an oxazoline compound, a mono-, di- or poly-oxazolidinone compound, a cyclic urea compound, a polyhydric metal salt, and an alkylene carbonate compound.

16 . The method of claim 1 , wherein the surface crosslinking agent in d) is added in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the ground polymer.

17 . The method of claim 1 , wherein the surface crosslinking agent in d) is added under a condition that a surface temperature of the polymer is 60 to 90° C.

18 . The method of claim 1 , wherein the surface crosslinking agent in d) has a temperature ranging from 5 to 40° C.

19 . The method of claim 1 , wherein the surface crosslinking reaction in e) is carried out for 10 to 120 min.

20 . The method of claim 1 , wherein e) is performed through heating by applying any one or more selected from the group of heat sources including steam, electricity, UV light, and IR light.

21 . The method of claim 1 , further comprising grinding the superabsorbent polymer to a particle size ranging from 150 to 850 μm, after the performing the surface crosslinking reaction in e).

22 . The method of claim 4 wherein the particles have superhydrophobicity with a water contact angle of 140° or more.

23 . The method of claim 4 wherein the particles have superhydrophobicity with a water contact angle of 145° or more.

Assignees

• Lg Chemical Ltd

Inventors

• Lee Seung-Mo
• Kim Young-Sam
• Oh Kyoung-Shil
• Yang Young-Ln
• Kim Ye-Hon

Classifications

• C08J3/075

  Macromolecular gels · CPC title

• C08J3/12

  Powdering or granulating · CPC title

• C08F2/48

  by ultraviolet or visible light · CPC title

• B01J20/3021

  Milling, crushing or grinding · CPC title

• C08F20/06

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