GB858127A - Polymer foam modification - Google Patents

Abstract

A foamed, open-cell, cellular polymeric polyurethane material in the form of an integrally formed 3-dimensionally reticulated structure comprises a network of strands defining the outlines of a plurality of polygons making up a plurality of polyhedrons, at least a plurality of the faces of the polyhedrons being open, and at least a portion of the linking groups in the polymer chain are selected from =C.CO.-, -O-CO.N=, =C-CO-N= and =N.CO.N= groups, the polymer being partially hydrolysed. Such material is produced by subjecting a foamed open cell polyurethane containing the specified groups to the action of a hydrolyzing agent under hydrolyzing conditions until the physical characteristics of the material are altered. Substantially all or only part of the cell faces may be removed, depending on the hydrolysis conditions. The products are believed to contain carboxyl and hydroxyl groups. The material subjected to hydrolysis may be one formed by reacting under foam-forming conditions (usually the presence of water and amine catalyst) a polyisocyanate and a polyester (which may be styrene- or oil-modified), polyether (which may contain amine residues or have been modified by reaction with an epoxide), polyesteramide or alcohol-modified urea-formaldehyde resin. Oil, wetting agent or silicone may be added. In the hydrolysis steam or hot water may be used alone or with a catalyst. Specified are enzymes such as lipase and pepsin; alkalis such as alkali metal or ammonium hydroxide, quaternary bases, amines and alkaline salts such as as trisodium phosphate; acids such as hydrochloric, sulphuric, phosphoric, toluene sulphonic and acetic acids. Figures are given which depict on an enlarged scale a typical cell before and after treatment. In a typical example a reaction product of toluene -2, 4- and -2, 6-diisocyanates and a polyester resin is converted to a foamed product by treatment with water, diethylethanolamine and polyoxyethylated vegetable oil dispersing agent. The foam is kneaded with sodium hydroxide solution at 50 DEG C. and washed and dried. A Table shows loss in weight, density, hydrophilicity and softness after various times of treatment. The products are useful as filtering devices, gas-liquid contacting devices, catalyst carriers, rug anchors, door mats, drain pads, scouring pads, sponges, insulating pads, tire liners, spacing devices, flexible partitions, draperies, upholstery padding, mattresses and pillows. Reference has been directed by the Comptroller to Specification 789,481.ALSO:A foamed, open-cell, cellular polymeric polyurethane material in the form of an integrally formed 3-dimensionally reticulated structure comprises a network of strands defining the outlines of a plurality of polygons making up a plurality of polyhedrons, at least a plurality of the faces of the polyhedrons being open, and at least a portion of the linking groups in the polymer chain are selected from =C,CO,-, -O-CO,N=, =C-CO-N= and =N,CO,N= groups, the polymer being partially hydrolysed. Such material is produced by subjecting a foamed open cell polyurethane containing the specified groups to the action of a hydrolyzing agent under hydrolysing conditions until the physical characteristics of the material are altered. Substantially all or only part of the cell faces may be removed, depending on the hydrolysis conditions. The products are believed to contain carboxyl and hydroxyl groups. The material subjected to hydrolysis may be one formed by reacting under foam-forming conditions (usually the presence of water and a minecatalyst) a polyisocyanate and a polyester (which may be styrene- or oil-modified), polyether (which may contain amine residues or have been modified by reaction with an epoxide), polyesteramide or alcohol-modified urea-formaldehyde resin. Oil, wetting agent or silicone may be added. In the hydrolysis steam or hot water may be used alone or with a catalyst. Specified are enzymes such as lipase and pepsin; alkalis such as alkali metal or ammonium hydroxide, quaternary bases, amines and alkaline salts such as trisodium phosphate; acids such as hydrochloric, sulphuric, phosphoric, toluene sulphonic and acetic acids. Drawings are given which depict on an enlarged scale a typical cell before and after treatment. In a typical example a reaction product of toluene -2,4- and -2,6- diisocyanates and a polyester resin is converted to a foamed product by treatment with water, diethylethanolamine and polyoxyethylated vegetable oil dispersing agent. The foam is kneaded with sodium hydroxide solution at 50 DEG C. and washed and dried. A Table shows loss in weight, density, hydrophilicity and softness after various times of treatment. The products are useful as filtering devices, gas-liquid contacting devices, catalyst carriers, rug anchors, door mats, drain pads, scouring pads, sponges, insulating pads, tire liners, spacing devices, flexible partitions, draperies, upholstery padding, mattresses and pillows. Reference has been directed by the Comptroller to Specification 789,481.