Alkyd modified siloxane coating compositions

Claim 1

A COATING COMPOSITION PARTICULARLY ADAPTED TO DEPOSIT BAKED FILMS CAPABLE OF ENDURING PROLONGED SERVICE AT ELEVATED TEMPERATURES WITHOUT BECOMING DISCOLORED APPRECIABLY, SAID COMPOSITION COMPRISING A SUBSTANTIAL AMOUNT OF A VEHICLE COMPOSED ESSENTIALLY OF AN AROMATIC HYDROCARBON SOLVENT SOLUTION OF A PRINCIPAL FILMFORMING MATERIAL, SAID PRINCIPAL FILM-FORMING MATERIAL BEING A COBODIED INTER-REACTION PRODUCT OF: (A) BETWEEN 25 AND 90 PARTS OF A THERMALLY-EVANESCENT, SUBSTANTIALLY NON-DISCOLORING MONOCARBOXYLIC ACID-MODIFIED ALKYD HAVING AN ACID NUMBER BELOW ABOUT 50, SAID ALKYD BEING THE RESINOUS REACTION PRODUCT OF: (1) POLYCARBOXYLIC ACID WHICH BOILS OR SUBLIMES ABOVE ABOUT 200* C., (2) POLYHDRIC ALCOHOL SELECTED FROM THE GROUP CONSISTING OF GLYCEROL, PENTAERYTHRITOL, TRIMETHYLOL PROPANE AND TRIMETHYLOL ETHANE; AND (3) MONOCARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF SATURATED ALIPHATIC ACIDS HAVING FROM 6 TO 10 CARBON ATOMS AND ARYL AND ARALKYL ACIDS HAVING NOT MORE THAN 11 CARBON ATOMS AND FREE OF NON-BENZENOID UNSATURATION, SAID MONOCARBOXYLIC ACID BEING PRESENT IN AN AMOUNT SUCH THAT THE TOTAL WEIGHT OF MONOCARBOXYLIC ACID ESTERS IS BETWEEN ABOUT 1/3 AND 1/2 OF THE TOTAL WEIGHT OF THEORETICAL ESTERS IN THE ALKYD; AND (B) BETWEEN ABOUT 75 AND 10 PARTS OF AN POLYSILOXANOL, SAID POLYSILOXANOL BEING CHARACTERIZED (1) BY HAVING IT SILICON ATOMS BONDED TOGETHER BY SI-O-SI LINKAGES, (2) BY HAVING THE REMAINING VALENCE OF ITS SAID SILICON ATOMS SATISFIED BY METHYL, PHENYL AND HYDROXY RADICALS, (3) BY HAVING A TOTAL OF BETWEEN 1 AND 1.7 METHYL AND PHENYL RADICALS PER SILICON ATOM OF WHICH TOTAL BETWEEN 10 AND 90 PER CENT ARE PHENYL RADICALS, (4) BY HAVING AN HYDROXYL CONTENT OF BETWEEN ABOUT 0.45% AND 20% BY WEIGHT OF SILOXANOL SOLIDS, AND (5) BY BEING SOLUBLE INAN AROMATIC HYDROCARBON SOLVENT; SAID FILM-FORMING MATERIAL BEING PRODUCED BY COBODYING SAID ALKYD AND SAID POLYSILOXANOL UNDER REFLUX CONDITIONS WITH REMOVAL OF WATER IN AN AROMATIC HYDROCARBON SOLVENT UNTIL A SUBSTANTIAL INCREASE IN VISCOSITY SHORT OF GELLATION HAS BEEN SECURED.