Prepare the paint film on the tin plate according to the brushing method of "General Preparation Method of Paint Film" (GB1727-79). Dry for 48 hours under constant temperature and humidity conditions after painting. Place the filter paper with the glossy side down on the paint film at a distance of not less than 1 cm from the edge of the sample, put it in a temperature and humidity control box, and preheat the filter paper at a temperature of 40 ± 1 degrees Celsius and a relative humidity of 80 ± 2%. Put the back viscosity Tester in the middle of the filter paper, and close the temperature and humidity control box. Rise to a temperature of 40 ± 1 degrees Celsius within 5 minutes, and a relative humidity of 80 ± 2%, maintain this condition for 10 minutes, quickly remove the measuring device vertically, and take out the sample. Place it under constant temperature and humidity conditions for 15 minutes, and observe the results with a four-fold magnifying glass.
rating
(1) The model is turned upside down, and the filter paper can fall freely, or tap a few times with the index finger of the hand holding the plate, and the filter paper can fall down as grade 1.
(2) Gently lift the filter paper sheet, allowing impressions, sticking with sparse and slight filter paper fibers, and the total area of the fibers is less than one-third of the square centimeter, which is grade 2.
(3) Gently lift the filter paper sheet to allow impressions and dense filter paper fibers, and the total area of the fibers is less than one-third square centimeters to one-half square centimeters as grade 3.
During the inspection, three samples are prepared for each sample at the same time for measurement, and the grade of the two samples with the same results is the evaluation result.
4. Maintenance and storage
After the sample is finished, the bottom surface of the paint film stickiness Tester should be scrubbed clean, put into the instrument box, and placed in a clean and dry place to avoid rust and affect the use of the instrument.
