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US 6,743,391 B2Granted
Superabsorbent polymers having delayed water absorption characteristics
AssigneeStockhausen GmbH & Co. KG
InventorsFang Sun, Bernfried A. Messner, Heather S. Jones
Life of this patent
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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.
Claims9
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.
Dependencies are inferred from the claim text.