Abstract: The invention disclosed is directed to a gel composition, including (a) an aliphatic saturated monocarboxylic acid having from about 10 to about 24 carbon atoms; (b) an interpolymer of ethylene and a vinyl ester of a monocarboxylic acid having from 1 to about 4 carbon atoms; (c) a tackifying resin; and (d) an organic solvent. Substrate surfaces to which the gel composition is applied typically exhibit good resistance to blocking and may be effectively heat sealed to other surfaces at relatively low temperatures in minimum time. In aspects of the invention the coated substrates may be polyolefinic or cellulosic sheet materials, including laminates thereof with vinylidene chloride interpolymer layers. Improved heat sealable substrates and processes for heat sealing are also described.