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US 2021/0268475 A1Published application
Super Absorbent Polymer and Method for Preparing Same
AssigneeLG Chem, Ltd.
InventorsHyemi Nam, Sang Gi Lee, Yeonsoo Kim, Chang Hun Lee
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Abstract
The present disclosure relates to: a super absorbent polymer having a rapid absorption rate and maintaining elasticity even in a condition of being pressed multiple times, thereby having excellent dryness characteristic; and a preparation method therefor. The super absorbent polymer of the present disclosure exhibits excellent performance for use in hygiene materials such as diapers.
Claims11
A super absorbent polymer in which a recovery rate of the super absorbent polymer calculated by the following Equation 1 is 85% or more:
- Recovery rate (%)=Fourth resilience value/First resilience value*100 [Equation 1]
- in the Equation 1,
- the first resilience value is a modulus (unit:
- Kpa) of the super absorbent polymer which is measured after 2 g of the super absorbent polymer is swollen in 200 mL of physiological saline (0.9 wt % NaCl) for 1 hour under no pressure, loaded into a DMA (Dynamic Mechanical Analysis) measuring device, pressed at room temperature (25° C.) under 0.72 psi for 5 minutes, and then pressure-released and allowed to stand for 10 minutes, and
- the fourth resilience value is the modulus (unit:
- Kpa) of the super absorbent polymer, which is measured for the fourth time after the process of measuring the first resilience value and then pressing again to measure a resilience value is further repeated three times in the same manner.
3 more elements
A method for preparing a super absorbent polymer comprising:
- polymerizing a monomer composition including an acrylic acid-based monomer having at least partially neutralized acidic groups, a foaming agent, an internal crosslinking agent, and a polymerization initiator to form a hydrogel polymer;
- chopping the hydrogel polymer through a chopper containing two or more hole plates arranged in series;
- drying, pulverizing and classifying the chopped hydrogel polymer to form a base polymer;
- and
- further crosslinking a surface of the base polymer powder in the presence of a surface crosslinking agent to form a surface crosslinked layer.
2 more elements
Dependencies are inferred from the claim text.