Surface cross-linked superabsorbent polymer particles and methods of making them
AssigneeThe Procter & Gamble Company
InventorsAndreas Flohr, Torsten Lindner
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Abstract
The present invention relates to superabsorbent polymer particles with improved surface cross-linking and their use in absorbent articles. The superabsorbent polymer particles of the present invention comprise polymer chain segments, wherein at least a part of the polymer chain segments are covalently cross-linked to each other and wherein at least a part of the cross-links comprise the reaction product of cross-linking molecules having at least two C═C double bonds and further comprise the reaction product of radical former molecules. These cross-links are present at surfaces of the superabsorbent polymer particles. Moreover, the invention relates a method for making these superabsorbent polymer particles.
Claims13
Superabsorbent polymer particles comprising polymer chain segments,
- wherein at least some of said polymer chain segments are covalently cross-linked to each other after formation of said superabsorbent polymer particles, and
- wherein the cross-links comprise the reaction product of cross-linking molecules having at least two C═C double bonds, and
- wherein each of said superabsorbent polymer particles comprises a surface and a core and wherein said cross-links are present on said surfaces of said superabsorbent polymer particles,
- wherein said cross-links comprising the reaction product of said cross-linking molecules having at least two C═C double bonds further comprise the reaction product of radical former molecules.
A method of surface cross-linking superabsorbent polymer particles which comprises the steps of
- a) providing superabsorbent polymer particles comprising polymer chain segments,
- b) adding a surface cross-linking composition comprising cross-linking molecules having at least two C═C double bonds and further comprising radical former molecules,
- c) exposing said superabsorbent polymer particles and said surface cross-linking composition to electromagnetic irradiation capable of activating said radical former,
- whereby said cross-linking molecules and said radical former molecules react with at least some of said polymer chain segments comprised at surfaces of the superabsorbent polymer particles to form covalent cross-links between said polymer chain segments, wherein said cross-links comprise the reaction product of said cross-linking molecule and wherein said cross-links further comprise the reaction product of said radical former molecules.
Dependencies are inferred from the claim text.