Monomer composition for preparing superabsorbent polymer comprised in an absorbent article

A method for making an absorbent article, the method comprising the step of making a monomer composition for preparing superabsorbent polymer, the monomer composition comprising:

• acrylic acid-based monomers having acid groups, at least a part of said acid groups being neutralized;
• a crosslinking agent;
• clay;
• a carbonate-based blowing agent;
• and a polymerization initiator,
• wherein, when irradiating heat and/or light to the monomer composition for preparing the superabsorbent polymer to progress a polymerization reaction, a normalized gel point represented by the following Formula 1 is 0.01 to 0.1:
• Normalized
• ⁢
• gel
• ⁢
• point
• =
• gel
• ⁢
• point
• ⁢
• (
• second
• )
• /
• total
• ⁢
• polymerization
• ⁢
• time
• ⁢
• (
• second
• )
• [
• Formula
• ⁢
• 1
• ]
• in the Formula 1, a gel point is a polymerization time at the intersection point of a storage modulus graph of the monomer composition for preparing the superabsorbent polymer according to a polymerization time, and a loss modulus graph of the monomer composition for preparing the superabsorbent polymer according to a polymerization time, the method comprising the steps of:
• mixing the acrylic acid-based monomers having acid groups, at least a part of said acid groups being neutralized;
• the crosslinking agent;
• the carbonate-based blowing agent;
• and the polymerization initiator;
• and
• adding the clay to the mixture, and shear mixing at a stirring speed of 6,500 rpm or more,
• wherein the method comprises the further step of incorporating the superabsorbent polymer prepared by the monomer composition in an absorbent article.

A method for making an absorbent article, the absorbent article comprising superabsorbent polymer, the method comprising the steps of:

• irradiating heat and/or light to a monomer composition for preparing superabsorbent polymer to polymerize, thus preparing hydrogel polymer,
• the monomer composition comprising:
• acrylic acid-based monomers having acid groups, at least a part of said acid groups being neutralized;
• a crosslinking agent;
• clay;
• a carbonate-based blowing agent;
• and a polymerization initiator,
• wherein, when irradiating heat and/or light to the monomer composition for preparing the superabsorbent polymer to progress a polymerization reaction, a normalized gel point represented by the following Formula 1 is 0.01 to 0.1:
• Normalized
• ⁢
• gel
• ⁢
• point
• =
• gel
• ⁢
• point
• ⁢
• (
• second
• )
• /
• total
• ⁢
• polymerization
• ⁢
• time
• ⁢
• (
• second
• )
• [
• Formula
• ⁢
• 1
• ]
• in the Formula 1, a gel point is a polymerization time at the intersection point of a storage modulus graph of the monomer composition for preparing the superabsorbent polymer according to a polymerization time, and a loss modulus graph of the monomer composition for preparing the superabsorbent polymer according to a polymerization time;
• drying, grinding and classifying the hydrogel polymer to form base resin;
• and
• forming a surface crosslink layer on the surface of the base resin, in the presence of a surface crosslinking solution comprising a surface crosslinking agent and a solvent,
• wherein the method further comprises the step of incorporating the superabsorbent polymer in an absorbent article.