These resorcinol-formaldehyde resins can be substituted for resorcinol to augment adhesion of rubber skim stocks for brass-plated steel tire cord and various synthetic tire fabrics. They are thermoplastic and require a methylene donor, e.g. hexamethoxymethylmelamine (HMMM) or hexamethylenetetramine (hexa) to complete the reaction and become thermoset. These resins were specifically formulated to have low vapor pressures which substantially reduce the fuming and weight loss that occur with resorcinol at processing temperatures above 150°C (302°F). The adhesive bonds formed with Penacolite Resins in dry bonding systems are thermally stable and resistant to hydrolysis. They are supplied in pastille form, become molten at processing temperatures, and contain no free formaldehyde.