Abstract: A polyurethane resin is composed of a polyol component, a polyisocyanate component and optionally, a chain extender component. At least a portion of the polyol component or chain extender component is a siloxane polyol component represented by the following formula (1) and/or formula (2): ##STR1## wherein R means an alkyl group, R' denotes a hydrogen atom or C.sub.1-5 alkyl group, k, l and m stand for 1-250, 0-5 and 0-50 respectively, and n is an integer of 1-3 in the formula (1) and an integer of 2-3 in the formula (2). A thermal recording material containing the polyurethane resin as a heat-resistant layer is also disclosed.

Abstract: A polyurethane resin is composed of a polyol component, a polyisocyanate component and optionally, a chain extender component. At least a portion of the polyol component or chain extender component is a siloxane polyol component represented by the following formula (1) and/or formula (2): ##STR1## wherein R means an alkyl group, R' denotes a hydrogen atom or C.sub.1-5 alkyl group, k, l and m stand for 1-250, 0-5 and 0-50 respectively, and n is an integer of 1-3 in the formula (1) and an integer of 2-3 in the formula (2). A thermal recording material containing the polyurethane resin as a heat-resistant layer is also disclosed.

Abstract: A polyurethane emulsion is composed of an organic solvent solution of a polyurethane resin containing silicone segments and/or fluorocarbon segments as backbones and/or side chains and water emulsified in the organic solvent solution. A sheet-like porous material having a porous layer of a polyurethane resin provided on a base material is produced by using the above polyurethane emulsion to form the porous layer.

Abstract: A heat-sensitive recording medium is composed of a base sheet, a heat-sensitive recording layer provided on one side of the base sheet and a heat-resistant layer provided on the other side of the base sheet. The heat-resistant layer is made of a film-forming resin modified with a modifier, which is a reaction product of a fluorine compound containing at least one reactive organic functional group and an organic polyisocyanate.

Abstract: A polyurethane dispersion contains (A) an organic solvent, (B) a polyurethane resin having a molecular weight of 20,000-500,000, and (C) fine particles obtained from an active-hydrogen containing polyfunctional compound, which contains functional groups having a molecular weight of 50 or smaller per functional group, and an organic polyisocyanate. The dispersion can be converted into an emulsion by emulsifying water therein. A sheet-like porous material is also obtained by impregnating and/or coating a base material with the emulsion, causing the thus-coated emulsion to gel and then drying the resultant base material. The dispersion has excellent stability. The emulsion can be gelatinized at a relatively high temperature in a rather short period time, thereby permitting efficient production of the sheet-like porous material. The sheet-like material has a very fine porous structure, is excellent in various properties and has superb water vapor transmission characteristics.