a heat - sensitive recording paper is described , comprising a support having formed thereon a heat - sensitive recording layer containing a colorless or pale - colored electron donating dye precursor and an electron accepting substance that reacts with said electron donating dye precursor to develop color , and an overlying protective layer containing a water - soluble polymeric binder and a pigment , wherein the back side of the support is provided with a backcoat layer containing an alkali salt of a styrene - maleic acid copolymer .