Structure having balanced pH profile
AssigneeKimberly-Clark Worldwide, Inc.
InventorsPalani Raj Ramaswami Wallajapet, Alice Y. Romans-Hess, Edwin T. Ta, Jian Qin
Life of this patent
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Abstract
Disclosed is an absorbent structure comprising an acidic or basic water-swellable, water-insoluble polymer, a basic or acidic second material, and, optionally, a buffering agent, wherein the absorbent structure exhibits desirable absorbent properties. Specifically, the present invention relates to an absorbent structure having the ability to absorb a large quantity of liquid while maintaining a substantially desired and balanced pH profile on or along the upper surface of the absorbent structure. The absorbent structure is useful in disposable absorbent products, such as those disposable absorbent products that are used to absorb body liquids.
Claims64
An absorbent structure to be used in contact with human skin of a wearer, the absorbent structure comprising an upper surface oriented toward the skin of the wearer and a lower surface oriented away from the skin of the wearer, the absorbent structure further comprising:
- a) a water-swellable, water-insoluble polymer having acidic functional groups, wherein the water-swellable, water-insoluble polymer has at least about 50 molar percent of the acidic functional groups in free acid form;
- and
- b) a basic material;
- wherein the absorbent structure exhibits a Wicking Capacity value that is at least about 5 grams per gram of absorbent structure and exhibits a pH on the upper surface that remains within the range of about 3 to about 8.
A disposable absorbent product comprising a liquid-permeable topsheet, a backsheet attached to the topsheet, and an absorbent structure positioned between the topsheet and the backsheet wherein the absorbent structure comprises:
- a) a water-swellable, water-insoluble polymer having acidic functional groups, wherein the water-swellable, water-insoluble polymer has at least about 50 molar percent of the acidic functional groups in free acid form;
- and
- b) a basic material;
- wherein the absorbent structure exhibits a Wicking Capacity value that is at least about 5 grams per gram of absorbent structure and exhibits a pH on the upper surface that remains within the range of about 3 to about 8.
The disposable absorbent product of claim 32 wherein the acidic water-swellable, water-insoluble polymer is prepared from polyacrylic acid, the basic material is selected from the group consisting of sodium hydrogen carbonate and sodium carbonate, and the buffering agent is citric acid.
An absorbent structure to be used in contact with human skin of a wearer, the absorbent structure comprising an upper surface oriented toward the skin of the wearer and a lower surface oriented away from the skin of the wearer, the absorbent structure further comprising:
- a). a water-swellable, water-insoluble polymer having basic functional groups, wherein the water-swellable, water-insoluble polymer has at least about 0.50 molar percent of the basic functional groups in free base form;
- and
- b) an acidic material;
- wherein the absorbent structure exhibits a Wicking Capacity value that is at least about 5 grams per gram of absorbent structure and exhibits a pH on the upper surface that remains within the range of about 3 to about 8.
A disposable absorbent product comprising a liquid-permeable topsheet, a backsheet attached to the topsheet, and an absorbent structure positioned between the topsheet and the backsheet wherein the absorbent structure comprises:
- a) a water-swellable, water-insoluble polymer having basic functional groups, wherein the water-swellable, water-insoluble polymer has at least about 50 molar percent of the basic functional groups in free base form;
- and
- b) a basic material;
- and
- c) a buffering agent having a pKa between about 2 to about 10;
- wherein the absorbent structure exhibits a Wicking Capacity value that is at least about 5 grams per gram of absorbent structure and exhibits a pH on the upper surface that remains within the range of about 3 to about 8.
Dependencies are inferred from the claim text.