Method for determining end point of polyamide modified vehicle cooks

Claim 1

IN THE PROCESS FOR THE PRODUCTION OF A THIXOTROPIC VEHICLE FOR PROTECTIVE COATINGS BY HEATING A REACTION MIXTURE COMPRISED OF A POLYAMIDE RESIN FORMED BY THE REACTION OF A POLYMERIZED UNSATURATED FATTY ACID WITH AN ALKYLENE POLYAMINE, AND AN ESTER BASE SELECTED FROM THE GROUP CONSISTING OF GLYCERIDE OILS, OIL-MODIFIED ALKYL RESINS AND VARNISH ESTER BODIES, THE METHOD FOR DETERMINING THE FURTHER REACTION TIME REQUIRED AT A GIVEN TEMPERATURE IN ORDER TO OBTAIN A PRODUCT HAVING PROPERTIES THE SAME AS THE PROPERTIES OF A STANDARD THIXOTROPIC VEHICLE PREPARED FROM THE SAME REACTANTS, WHICH COMPRISES DISSOLVING WITH HEAT A SAMPLE OF THE REACTION MIXTURE BEFORE THE REACTION END-POINT HAS BEEN REACHED IN A SOLVENT IN WHICH BOTH THE ESTER BASE AND THE REACTION PRODUCT ARE SOLUBLE BOTH WHEN HOT AND WHEN COLD AND WHICH FORMS A SOLUTION THEREWITH IN WHICH THE UNREACTED POLYAMIDE RESIN IS APPRECIABLY SOLUBLE HOT BUT SUBSTANTIALLY INSOLUBLE COLD, COOLING THE RESULTING SOLUTION TO PRECIPITATE THE UNREACTED POLYAMIDE RESIN CONTAINED THEREIN TO FORM A SUSPENSION THEREOF IN THE SOLUTION, MEASURING THE LIGHT TRANSMISSIBILITY OF SAID SUSPENSION, READING THE FURTHER REACTION TIME REQUIRED CORRESPONDING TO SAID DETERMINED TRANSMISSIBILITY VALUE FROM A GRAPH, AND CONTINUING THE REACTION UNTIL THE FURTHER REACTION TIME DETERMINED HAS ELAPSED, SAID GRAPH HAVING BEEN PLOTTED TO SHOW THE RELATIONSHIP BETWEEN REACTION TIME AND LIGHT TRANSMISSIBILITY OF TEST SUSPENSIONS PREPARED FROM SAMPLES TAKEN AT INTERVALS DURING THE COURSE OF THE REACTION AT SAID GIVEN TEMPERATURE USED TO PREPARE SAID STANDARD THIXOTROPIC VEHICLE WHOSE PROPERTIES ARE TO BE DUPLICATED, SAID TEST SUSPENSIONS HAVING BEEN PREPARED USING THE SAME SOLVENT AND IN THE SAME PROPORTIONS AS THOSE USED TO PREPARE SAID FIRST-DESCRIBED TEST SUSPENSION.