1. Measurement of conductivity
The conductivity of electrophoretic paint liquid is caused by the movement of charged particles (resin) and high electrons (electrolyte) in the paint liquid in the electric field. situation etc. From the perspective of construction, it is related to the water quality of the dilution water and the impurities brought in during the electrophoresis of the workpiece. The determination of electrical conductivity is of great significance to the quality control of the production and construction of electrophoretic paint. Its measurement method is to use a conductivity meter, expressed in µs/cm.
Determination method (measured according to HG/T3335-1997 conductivity)
(1) Install and debug the conductivity meter according to the instruction manual of the conductivity meter.
(2) Prepare the electrophoretic paint solution according to the product standard requirements, and keep the temperature at 25°C ± 0.5°C on a constant temperature Water Bath furnace.
(3) Insert the conductivity electrode calibrated according to the instruction manual into the electrophoretic paint solution to be tested, operate according to the requirements of the instruction manual, read the reading indicated by the pointer, and repeat 3 times, and take the average value, which is the electrophoretic paint solution under test. The conductivity of the paint.
2. Determination of non-volatile content
This method is applicable to the determination of non-volatile matter in electrophoretic paint, bath solution and ultrafiltrate
(1) Instruments and pharmaceutical evaporating dishes; air circulation ovens; analytical balances; ethanol
(2) Operation steps:
① Weigh a specified amount of sample (accurate to 1mg)
Electrophoretic paint (original paint): 1.5~2g,
Bath liquid: 2~2.5g, ultrafiltrate: 10~15g
②Level the sample into a uniform thin layer
③Put it in a 120°C oven, bake for 1 hour, take it out and place it in a desiccator to cool
④ Accurately weigh the cooled sample and record the reading
(3) Calculation of results
(4) Precautions,
①Parallel measurement is required,
② Relative error needs to be less than 2%
③Average of measurement results
