Abstract: There are provided a useful resin composition for a back-surface layer and a heat-sensitive transfer recording material using the same, wherein under the circumstances where the temperature of thermal heads has been increased, the back-surface layer of the formed heat-sensitive transfer recording material has more excellent heat resistance, damage to a thermal head can be alleviated, and durability is excellent in that bleeding is suppressed even if the silicone content is increased. The present invention provides a resin composition for a back-surface layer to be used for forming a back-surface layer of a heat-sensitive transfer recording material, the resin composition containing, as film-forming components, a siloxane-modified urethane- or urea-based resin A, a resin B, and a cross-linking agent C, wherein the resin A contains a polysiloxane component in a range of 5 to 55%, the resin B has at least one active-hydrogen-containing group and has a glass transition point of lower than 100° C.

Abstract: Disclosed is a polyurethane resin containing a polyol component and an isocyanate component, wherein (1) the polyol component contains a polycarbonate diol component, and the isocyanate component contains a linear aliphatic isocyanate, (2) the polycarbonate diol component has a number-average molecular weight of 500 to 3000, and contains a diol-derived structure having 3 to 10 carbon atoms in the structure thereof, and (3) 10 mol % or more of the isocyanate component is a linear aliphatic isocyanate component having 4 to 10 carbon atoms.