This method is suitable for the determination of pH value of electrophoretic paint raw paint, bath solution, electrode solution and ultrafiltrate.
(1) Instruments and equipment
pH meter; electrode (anode and cathode electrophoresis materials should use their own dedicated pH measurement electrodes); 100mL beaker; thermometer; buffer solution: pH7 and pH5 buffer solutions are used for cathodic electrophoretic paint, pH7 and pH9.2 buffer solutions are used for anode For electrophoretic paint.
Cleaning solution for cathodic electrophoretic paint: mix high-sonium-free water and cellosolve (volume ratio 1:1), and then adjust the pH value to 3~4 with formic acid.
Cleaning solution for anodic electrophoretic paint: high-sonium-free water and adjust the pH value to 3~4.
(2) Operation steps (taking cathodic electrophoretic paint as an example)
(1) Calibration of the pH combination electrode: Rinse the combination electrode with high-sonium-free water, adjust to the accurate buffer index with pH7 buffer solution (after adjusting the temperature), then rinse the electrode with high-sonium-free water and check with pH5 buffer solution, the pH value should be 5, otherwise it should be checked again.
(2) Measure the pH value: measure the temperature of the sample to keep it constant, rinse the electrode with high-submerged water, then immerse the electrode in the sample under agitation, and deduce the pH value after a few seconds.
(3) Clean the electrodes and store them according to the instructions of the instrument.
