Super Absorbent Polymer

Patent metadata

Field	Value
Publication number	US-2021031169-A1
Application number	US-201816632789-A
Country	US
Kind code	A1
Filing date	Aug 14, 2018
Priority date	Sep 5, 2017
Publication date	Feb 4, 2021
Grant date	—

Abstract

The present invention relates to a super absorbent polymer. The super absorbent polymer exhibits excellent initial absorption capacity, and thus can provide a sanitary material such as a diaper or a sanitary napkin which can quickly absorb body fluids and impart a dry and soft touch feeling.

First claim

1 . A super absorbent polymer comprising:
a base polymer powder including a cross-linked polymer obtained by crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group of which at least a part is neutralized in the presence of an encapsulated foaming agent; and a surface cross-linked layer that is further cross-linked from the cross-linked polymer and is formed on the base polymer powder, wherein an initial absorption capacity of the super absorbent polymer, calculated according to the following Calculation Formula 1 is at least 30 g/g,
Initial absorption capacity (g/g)=[ W 2 (g)−W 1 (g)]/W 0 (g)−1   [Calculation Formula 1]

wherein in Calculation Formula 1, W 0 (g) is an initial weight (g) of the super absorbent polymer, W 1 (g) is a weight of a nonwoven fabric-made empty bag not containing the super absorbent polymer, which is measured after immersing the empty bag not containing the super absorbent polymer in a physiological saline solution at 36° C. for 1 minute, and then dehydrating the empty bag by gravity for 1 minute, and W 2 (g) is a weight of a nonwoven fabric-made bag containing the super absorbent polymer, which is measured after immersing and absorbing the bag containing the polymer in a physiological saline solution at 36° C. for 1 minute, and then dehydrating the same by gravity for 1 minute.

2 . The super absorbent polymer according to claim 1 , wherein the super absorbent polymer has a centrifuge retention capacity (CRC) for a physiological saline solution of 30 to 45 g/g.

3 . The super absorbent polymer according to claim 1 , wherein the super absorbent polymer has an initial absorption capacity calculated according to Calculation Formula 1 of 40 to 60 g/g, and a centrifuge retention capacity (CRC) for a physiological saline solution of 35 to 40 g/g.

4 . The super absorbent polymer according to claim 1 , wherein the encapsulated foaming agent has a structure including a core containing hydrocarbon and a shell surrounding the core and formed of a thermoplastic resin, and has a maximum expansion size in air of 20 to 190 μm.

5 . The super absorbent polymer according to claim 1 , wherein the encapsulated foaming agent has an average diameter of 5 to 50 μm.

6 . The super absorbent polymer according to claim 1 , wherein the encapsulated foaming agent has an expansion ratio in air of 3 to 15 times.

7 . The super absorbent polymer according to claim 4 , wherein the hydrocarbon is at least one selected from the group consisting of n-propane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, cyclopentane, n-hexane, iso-hexane, cyclohexane, n-heptane, iso-heptane, cycloheptane, n-octane, iso-octane, and cyclooctane.

8 . The super absorbent polymer according to claim 4 , wherein the thermoplastic resin is a polymer formed from at least one monomer selected from the group consisting of (meth)acrylate, (meth)acrylonitrile, aromatic vinyl, vinyl acetate, vinyl halide and vinylidene halide.

9 . A sanitary material comprising the super absorbent polymer of claim 1 .

10 . The sanitary material according to claim 7 , wherein the sanitary material is a diaper or a sanitary napkin.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Kyu Pal
• Kim Gi Cheul
• Kim Ki Hyun
• Lee Seul Ah
• Lee Sang Gi

Classifications

• C08J9/10

  developing nitrogen {, the blowing agent being a compound containing a nitrogen-to-nitrogen bond} · CPC title

• C08J2201/026

  Crosslinking before of after foaming · CPC title

• C08J9/141 Primary

  Hydrocarbons · CPC title

• C08J3/12

  Powdering or granulating · CPC title

• A61L15/24 Primary

  Macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds; Derivatives thereof {(A61L15/225 takes precedence)} · CPC title