Absorbent structures comprising coated super-absorbent polymer particles
This invention is directed to super-absorbent material, which comprises a super absorbent polymer core that is coated with an organic, polar coating agent, and whereby the particulate super-absorbent material has a contact angle and a corresponding cos CA m (as defined herein), whereby the cos CA m is more than 0.3, and whereby, when said coating agent is in the form of particles, said coating agent particles have a (weight) mean particle size of from 0.001 to 1 micron. The material is useful for absorbent structures and absorbent articles (comprising such structures). The coated super-absorbent material is typically present in said absorbent structure at least at a concentration of 50% by weight of the structure, preferably even 80% or even 90%. The invention also provides a process for making the absorbent material.
1. An absorbent article comprising an absorbent structure, said absorbent structure comprising a particulate super-absorbent material comprising a particulate core of super-absorbent polymers, said particulate core coated with a coating agent comprising an organic coating compound which has one or more polar groups, and wherein the coated particulate super-absorbent material has a contact angle and a corresponding cos CA m , wherein the cos CA m is greater than 0.3 and has a specific surface area of at least 0.25 m 2 per gram, further wherein there is a gradient of coated super absorbent material within the total superabsorbent material of the absorbent structure, and wherein the absorbent structure comprises less than 10% by weight of absorbent fibers.
2. The absorbent article of claim 1 wherein said absorbent structure further comprises cellulose fibers.
3. The absorbent article of claim 1 wherein said absorbent article is selected from the group consisting of a sanitary napkin, a panty liner, a diaper, a training pant, and an adult incontinence article.
4. The absorbent article of claim 1 wherein the absorbent structure comprises less than 5% by weight of absorbent fibrous material.
5. The absorbent article of claim 1 wherein the absorbent structure comprises more than 50% by weight of super absorbent.
6. The absorbent article of claim 1 wherein the absorbent structure comprises a gradient of uncoated superabsorbent material.