Water absorbent structures
Patent 4902565 Issued on February 20, 1990. Estimated Expiration Date: 
July 28, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
July 28, 2008. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesSandwich construction and a method of making a sandwich construction Patent #: 4826723 InventorAssigneeApplicationNo. 225204 filed on 07/28/1988US Classes:428/315.5, Voids specified as micro428/315.9, Composite has more than two layers428/316.6, Plural void-containing components428/317.1, With component specified as adhesive or bonding agent428/913, MATERIAL DESIGNED TO BE RESPONSIVE TO TEMPERATURE, LIGHT, MOISTURE, ETC.604/368, Collagen or gelling material604/369Foam or cellular structure materialExaminersPrimary: Van Balen, William J.Attorney, Agent or FirmInternational ClassesB32B 003/26B32B 007/12 Foreign Application Priority Data1987-07-29 GBAbstractWater absorbent structures are disclosed which are intended for use as wound dressings, disposable nappies (diapers) or similar applications. The structures comprise a flexible porous substrate, e.g. an open-cell foam web which is impregnated with (a) a solid, water-insoluble water absorber which has a fine particle size and is capable of absorbing at least 30 times its weight of water and (b) a hydrophilic binder which retains the water absorber in the substrate and comprises a substantially non-cross-linked, water-insoluble, hydrogel forming polymer.Component (a) has a high affinity for water due to the presence of hydrophilic groups in the polymer, but is insoluble in water and in common organic solvents. Component (b) is also water-insoluble, but because of its non-cross-linked structure is soluble in common organic solvents, such as ethanol. | |
