Preparation method of superabsorbent polymer and superabsorbent polymer prepared thereby

A superabsorbent polymer comprising a crosslinked polymer formed by polymerization and internal crosslinking of water-soluble ethylene-based unsaturated monomers and a polycarboxylic acid-based copolymer having repeating units represented by the following Chemical Formula 1-a and Chemical Formula 1-b, which is present on the crosslinked polymer:

• wherein, in Chemical Formula 1-a and 1-b,
• R1, R2, and R3 are each independently hydrogen or an alkyl group having 1 to 6 carbon atoms,
• RO is an oxyalkylene group having 2 to 4 carbon atoms,
• M1 is hydrogen or a monovalent metal or non-metal ion,
• X is —COO—, an alkyloxy group having 1 to 5 carbon atoms, or an alkyldioxy group having 1 to 5 carbon atoms,
• m is an integer of 1 to 100,
• n is an integer of 1 to 1000, and
• p is an integer of 1 to 150, and provided that there are two or more of p, two or more repeating (—RO—)s may be the same as or different from each other,
• wherein the superabsorbent polymer has liquid permeability (SFC) of 60×10−7 cm3*s/g to 130×10−7 cm3*s/g, centrifuge retention capacity (CRC) of 27 g/g to 35 g/g, absorbency under pressure (AUP) of 23 g/g to 27 g/g, and permeability dependent absorption under pressure (PDAUP) of 20 g/g to 25 g/g.