Super absorbent polymer and its preparation method
The present disclosure relates to a super absorbent polymer exhibiting improved rewetting property and excellent absorption property, and a preparation method of the same. This preparation method of a super absorbent polymer includes the steps of: preparing a base resin in which an acrylic acid-based monomer having at least partially neutralized acidic groups and an internal cross-linking agent are cross-linked and polymerized; and heating the base resin in the presence of a surface cross-linking agent to carry out surface modification, wherein the internal cross-linking agent includes a poly(meth)acrylate of polyols-based first internal cross-linking agent and a polyglycidyl ether of polyols-based second internal cross-linking agent in a specific weight ratio.
1. A super absorbent polymer, comprising:
a base resin comprising a cross-linked polymer obtained by cross-linking an acrylic acid-based monomer having at least partially neutralized acidic groups by a medium of an internal cross-linking agent;
a surface cross-linked layer formed on a particle surface of the base resin, wherein the cross-linked polymer is additionally cross-linked by a medium of a surface cross-linking agent; and
a polyvalent metal salt formed on the surface cross-linked layer,
wherein the internal cross-linking agent comprises a poly(meth)acrylate of polyols-based first internal cross-linking agent and a polyglycidyl ether of polyols-based second internal cross-linking agent in a weight ratio of 1:20 to 1:300.
2. The super absorbent polymer of claim 1 ,
wherein the polyvalent metal salt comprises an aluminum salt.
3. The super absorbent polymer of claim 1 ,
wherein a rewetting property of the super absorbent polymer, is 1.0 g, wherein the rewetting property is a weight of water came out from the super absorbent polymer after immersing 1 g of the super absorbent polymer in 100 g of tap water, swelling for 10 minutes, and leaving it on a filter paper for 50 minutes.
4. The super absorbent polymer of claim 1 , wherein the acrylic acid-based monomer comprises acrylic acid, methacrylic acid, or a monovalent metal salt, a divalent metal salt, an ammonium salt, or an organic amine salt thereof.