Sealant compositions and commutator sealed therewith

Claim 1

A COMPOSITION ADAPTED FOR SEALING COMMUTATORS COMPRISING AN INTIMATE ADMIXTURE OF (A) FROM 85% TO 60% BY WEIGHT OF AN EPOXY RESIN-DIMER ACID PLASTICIZED WITH A POLYESTER RESIN, THERE BEING FROM 1.25 TO 2.5 PARTS BY WEIGHT OF EPOXY RESIN-DIMER ACID FOR EACH ONE PART BY WEIGHT OF POLYESTER RESIN, SAID EPOXY RESIN-DIMER ACID HAVING BEEN DERIVED BY REACTING (1) FROM 10 TO 90 PARTS BY WEIGHT OF THE REACTION PRODUCT OF FROM ONE TO TEN MOLS OF AN EPIHALOHYDRIN FOR EACH ONE MOL OF A DIHYDRIC PHENOL WITH (2) FROM 90 TO 10 PARTS BY WEIGHT OF THE DIMERIZATION PRODUCT OF AT LEAST ONE UNSATURATED FATTY ACID HAVING FROM 10 TO 24 CARBON ATOMS PER MOLECULE, AND SAID POLYESTER PLASTICIZER HAVING BEEN DERIVED BY HEATING ABOVE 150* C. BUT NOT ABOVE 260*C. (A) ONE MOL OF AT LEAST ONE UNSATURATED ACIDIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF FUMARIC ACID, ITACONIC ACID, MALEIC ACID, MALEIC ANHYDRIDE, CHLORMALEIC ACID, CITRACONIC ANHYDRIDE, AND CITRACONIC ACID, (B) FROM 10 TO 15 MOLS OF ADIPIC ACID, (C) FROM 0.5 TO 5 MOLS OF NEOPENTYL GLYCOL, AND (D) FROM 14 TO 9 MOLS OF ETHYLENE GLYCOL, THE GLYCOLS PROVIDING SUFFICIENT HYDROXYL GROUPS TO EXCEED BY AT LEAST 5% BUT NOT MORE THAN 15% THE NUMBER OF CARBOXYL GROUPS IN THE ADIPIC ACID AND THE ACIDIC COMPOUND, THE HEATING BEING CONTINUED UNTIL THE POLYESTER RESIN HAS AN ACID NUMBER BELOW 15 AND A GARDNER-HOLDT VISCOSITY OF ABOUT G TO M IN A 50% SOLUTION IN STYRENE, (B) FROM 15% TO 40% BY WEIGHT OF A FINELY DIVIDED INORGANIC SOLID FILLER OF WHICH AT LEAST 10% BASED ON THE WEIGHT OF THE TOTAL COMPOSITION, IS A FINELY DIVIDED SILICA HAVING AN AVERAGE PARTICLE SIZE OF LESS THAN ONE MICRON, AND (C) FROM 0.1% TO 15% OF A BLOWING AGENT.