Superabsorbent polymers having delayed water absorption characteristics
AssigneeStockhausen GmbH & Co. KG
InventorsFang Sun, Bernfried A. Messner, Heather S. Jones
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Abstract
A superabsorbent polymer comprising a delayed absorption superabsorbent polymer having a free water absorbency property of absorbing less than about 3 grams of aqueous saline per gram of superabsorbent polymer in about 6 seconds, for a full particle size distribution of superabsorbent polymer ranging from about 40 micrometers to about 890 micrometers.
Claims29
A superabsorbent polymer comprising a delayed absorption, particulate superabsorbent polymer having a free water absorption property of absorbing less than about 3 grams of water per gram of superabsorbent polymer in about 6 seconds, for a full particle size. distribution ranging from about 40 micrometers to about 890 micrometers.
A method for making a delayed absorption, particulate superabsorbent polymer, said method comprising:
- (a) preparing a particulate superabsorbent polymer, and
- (b) subjecting the particulate superabsorbent of step (a) to a thermal profile having a first part and a second part, wherein the first part comprises heating the superabsorbent polymer with an increasing temperature from a beginning temperature to a final increased temperature and the second part comprises maintaining heating of the superabsorbent polymer at a constant temperature that is at least about 5° C. higher than the final increased temperature of the first part, and wherein the temperatures and the times for heating of each of the first part and the second part are sufficient to achieve a delayed absorption, particulate superabsorbent polymer having a free water absorption property of absorbing less than about 3 grams of aqueous saline per gram of superabsorbent polymer in about 6 seconds, for a full particle size distribution ranging from about 40 micrometers to about 890 micrometers.
A wet-laid web comprising a fibrous component and a superabsorbent polymer component, wherein:
- (a) the superabsorbent polymer comprises a delayed absorption, particulate superabsorbent polymer having a free water absorption property of absorbing less than about 3 grams of water per gram of superabsorbent polymer in about 6 seconds, for a full particle size distribution ranging from about 40 micrometers to about 890 micrometers;
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- (b) the weight ratio of the superabsorbent polymer component to the fibrous component is controlled to be in a range from about 90:10 to about 5:95.
A method for improving the solids content of a wet-laid web having a fibrous component and a superabsorbent polymer component, said method comprising:
- (a) preparing a particulate superabsorbent polymer;
- (b) forming the superabsorbent polymer component by subjecting the particulate superabsorbent of step (a) to a thermal profile having a first part and a second part, wherein the first part comprises heating the superabsorbent polymer with an increasing temperature from a beginning temperature to a final increased temperature and the second part comprises maintaining heating of the superabsorbent polymer at a constant temperature that is at least about 5° C. higher than the final increased temperature of the first part, and wherein the temperatures and the times for heating of each of the first part and the second part are sufficient to achieve a delayed absorption, particulate superabsorbent polymer having a free water absorption property of absorbing less than about 3 grams of aqueous saline per gram of superabsorbent polymer in about 6 seconds, for a full particle size distribution ranging from about 40 micrometers to about 890 micrometers;
- (c) forming an aqueous suspension of the fibrous component together with the superabsorbent polymer component from step (b);
- and
- (d) drying the suspension from step (c) to achieve a wet-laid web having an improved solids content.
Dependencies are inferred from the claim text.