Super absorbent polymer

Patent metadata

Field	Value
Publication number	US-2016208035-A1
Application number	US-201514882619-A
Country	US
Kind code	A1
Filing date	Oct 14, 2015
Priority date	Jan 16, 2015
Publication date	Jul 21, 2016
Grant date	—

Abstract

The present invention relates to a super absorbent polymer. The super absorbent polymer according to the present invention includes surface crosslinked polymer particles prepared by surface crosslinking particles of a base resin, wherein the base resin is polymerized from water-soluble ethylene-based unsaturated monomers, and a water-soluble component, in which the water-soluble component is present in an amount of 5% by weight or less based on the total weight of the super absorbent polymer, when measured after free swelling the super absorbent polymer in a 0.9% NaCl solution for 1 hour, and the super absorbent polymer has a permeability of 50 seconds or shorter. According to the present invention, provided is a super absorbent polymer having excellent liquid permeability even when swollen without a reduction in centrifuge retention capacity or absorbency under load while having improved permeability.

First claim

What is claimed is:

1 . A super absorbent polymer, comprising:
surface crosslinked polymer particles are prepared by surface crosslinking particles of a base resin, wherein the base resin is polymerized from a monomer composition including water-soluble ethylene-based unsaturated monomers; and a water-soluble component, wherein the water-soluble component is present in an amount of 5% by weight or less based on the total weight of the super absorbent polymer, when measured after free swelling the super absorbent polymer in a 0.9% NaCl solution for 1 hour, and wherein the super absorbent polymer has a permeability calculated by the following Equation 1 of about 50 seconds or shorter:
Permeability (sec)= T S −T 0   [Equation 1]

wherein T S (sec) is the time required for an amount of a 0.9% saline solution to permeate a saline-absorbed super absorbent polymer under a load of 0.3 psi, wherein the saline-absorbed super absorbent polymer is prepared by swelling 0.2 g of super absorbent polymer powder with the 0.9% saline solution for 30 minutes, and T 0 (sec) is the time required for the amount of the 0.9% saline solution to flow under the load of 0.3 psi in the absence of the saline-absorbed super absorbent polymer.

2 . The super absorbent polymer of claim 1 , wherein the water-soluble component having a ratio (dwt/d(log M)) of 0.9 or less over molecular weights (M) ranging from 100,000 to 300,000 g/mol, when measured from an eluted solution after free swelling 1 g of the super absorbent polymer in 200 ml of a 0.9% NaCl solution for 1 hour.

3 . The super absorbent polymer of claim 1 , wherein a centrifuge retention capacity (CRC) ranges from about 26 to about 32 g/g.

4 . The super absorbent polymer of claim 1 , wherein an absorbency under load (0.7 psi AUL) ranges from about 20 to about 26 g/g.

5 . The super absorbent polymer of claim 1 , wherein the base resin is polymerized in the presence of an internal cross linking agent, which crosslinks polymers present in the interior of the polymer particles.

6 . The super absorbent polymer of claim 5 , wherein the internal cross linking agent is present in an amount ranging from 0.1 to 0.5 wt % based on the monomer composition.

7 . The super absorbent polymer of claim 1 , wherein surface crosslinked polymer particles are prepared by surface crosslinking particles of a base resin using a surface crosslinking solution including a surface crosslinking agent at a temperature ranging from 180 to 200° C.

8 . A hygiene product including the super absorbent polymer of claim 1 .

9 . A disposable diaper including the super absorbent polymer of claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Ryu Chul Hee
• Lee Hyemin

Classifications

• C08J3/245

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

• C08F222/102

  of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate · CPC title

• C08J2300/14

  Water soluble or water swellable polymers, e.g. aqueous gels · CPC title

• C08F20/10

  Esters · CPC title

• C08J3/075 Primary

  Macromolecular gels · CPC title