A blocked mercaptosilane of the structure: G-C(═O)—S—CH2CH2CH2SiX3 is disclosed wherein each X is an independently selected RO— group or R— group wherein each R is independently selected from the group consisting of hydrogen, alkyl that may or may not contain unsaturation, alkenyl groups, aryl groups, and aralkyl groups, such moieties other than hydrogen having from 1 to 18 carbon atoms, at least one X is RO—, and G is a monovalent alkyl group.