# US 12,179,172 B2 · Method of preparing superabsorbent polymer and superabsorbent polymer

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- Number: US 12,179,172 B2
- Document ID: US12179172B2
- Status: Granted
- Kind: B2
- Application number: 16/968,784
- Filed: 2019-11-27
- Published: 2020-12-24
- Granted: 2024-12-31
- Earliest claimed: 2018-12-11
- Assignees: LG Chem, Ltd.
- Applicants: LG Chem, Ltd.
- Inventors: Yong Seok Choi; Yeon Woo Hong; Eunji Shin; Taebin Ahn
- Web page: https://patentgrep.com/patent/US12179172B2

## CPC

- B01J 20/261: {obtained by reactions only involving carbon to carbon unsaturated bonds (macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds per se C08F)}
- B29B 9/12: characterised by structure or composition
- B01J 20/267: {Cross-linked polymers}
- B01J 20/28016: {Particle form}
- B01J 20/3021: {Milling, crushing or grinding}
- B29B 9/02: by dividing preformed material
- B29B 9/14: fibre-reinforced
- B29B 9/16: Auxiliary treatment of granules
- C08F 2/10: Aqueous solvent
- C08F 2/50: with sensitising agents
- C08F 220/06: Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
- C08F 222/102: {of dialcohols, e.g. ethylene glycol di(meth)acrylate or 1,4-butanediol dimethacrylate}
- C08J 3/075: Macromolecular gels
- C08J 3/12: Powdering or granulating
- C08J 3/245: {Differential crosslinking of one polymer with one crosslinking type, e.g. surface crosslinking}
- C08K 3/30: Sulfur-, selenium- or tellurium-containing compounds
- C08K 5/5397: Phosphine oxides
- C08K 7/02: Fibres or whiskers
- C08L 33/02: Homopolymers or copolymers of acids; Metal or ammonium salts thereof
- C08L 97/02: Lignocellulosic material, e.g. wood, straw or bagasse {(manufacture of articles made from lignocellulosic material by dry processes B27N)}
- B01J 2220/68: Superabsorbents
- B29B 2009/125: {Micropellets, microgranules, microparticles}
- C08J 2300/14: Water soluble or water swellable polymers, e.g. aqueous gels
- C08J 2333/02: Homopolymers or copolymers of acids; Metal or ammonium salts thereof
- C08K 2003/3045: {Sulfates}
- C08K 2201/004: Additives being defined by their length
- C08L 1/02: Cellulose; Modified cellulose
- C08L 23/12: Polypropene
- C08L 29/04: Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
- C08L 77/06: Polyamides derived from polyamines and polycarboxylic acids (C08L77/10 takes precedence)
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B29B: PREPARATION OR PRETREATMENT OF THE MATERIAL TO BE SHAPED; MAKING GRANULES OR PREFORMS; RECOVERY OF PLASTICS OR OTHER CONSTITUENTS OF WASTE MATERIAL CONTAINING PLASTICS
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

Provided are a superabsorbent polymer and a preparation method thereof. More particularly, provided are a superabsorbent polymer including a fine powder reassembly, wherein the superabsorbent polymer exhibits excellent absorption performances and absorption rate, and does not cause deterioration of physical properties such as water retention capacity (CRC) or absorbency under pressure (AUP), and a preparation method thereof.

## Claims

### Claim 1

A method of preparing a fine powder reassembly, the method comprising:
performing thermal polymerization or photo-polymerization of a monomer composition including a water-soluble ethylenically unsaturated monomer and a polymerization initiator to prepare a water-containing gel polymer;
drying, pulverizing, and size-sorting the water-containing gel polymer to classify the water-containing gel polymer into a fine powder having a particle size of less than 150 μm and a normal particle having a particle size of 150 μm to 850 μm;
mixing a fiber of a fluff pulp and a synthetic polymeric fiber with the fine powder and water to prepare a fine powder aqueous solution, wherein the fine powder aqueous solution includes the fiber in an amount of 1 part by weight or more to less than 20 parts by weight with respect to 100 parts by weight of the fine powder; and
stirring the fine powder aqueous solution to prepare the fine powder reassembly, wherein the fiber has a width of 1 μm to 80 μm.

### Claim 2 (depends on 1)

The method of preparing a fine powder reassembly of claim 1, wherein the fiber has a length of 1 mm to 20 mm.

### Claim 3 (depends on 1)

The method of preparing a fine powder reassembly of claim 1, wherein the synthetic polymeric fiber is one or more selected from the group consisting of nylon, polypropylene, polyethylene, polyester, polyacrylonitrile, polyvinyl chloride, polyvinyl alcohol, polyacrylate, and acetate.

### Claim 4 (depends on 1)

The method of preparing a fine powder reassembly of claim 1, wherein the fine powder aqueous solution includes water in an amount of 50 parts by weight to 150 parts by weight with respect to 100 parts by weight of the fine powder.

### Claim 5 (depends on 1)

A method of preparing a superabsorbent polymer comprising the method of preparing a fine powder reassembly of claim 1, further comprising drying, pulverizing, and size-sorting the fine powder reassembly to obtain the superabsorbent polymer having a particle size of 150 μm to 850 μm.

### Claim 6 (depends on 5)

The method of preparing a superabsorbent polymer of claim 5, further comprising surface-crosslinking the superabsorbent polymer having the particle size of 150 μm to 850 μm to obtain a surface-crosslinked superabsorbent polymer.