1. Determination of heat resistance of coating film
The heat resistance of the coating film can be determined according to the method in the national standard GB1735-79 "Paint Film 1 Heat Resistance Determination Method". This standard is used for the determination of the heat resistance of paint films. Use blast constant temperature oven or high-temperature furnace to heat, after reaching the specified temperature and time, the heat resistance performance of the paint film is indicated by the physical properties or the surface changes of the paint film.
(1) Materials and equipment
Tinplate: 50mmX120mmX(0.2~0.3)mm.
Thin steel plate: (GB708-65) 50mmX120mmX (0.45~0.55)mm.
Blast constant temperature oven
High temperature furnace
(2) Measurement method
According to GB1727-79 "general preparation method of paint film", prepare paint film on four thin steel plates (or the model specified in the product standard). After the paint film is hard-dried, place the three painted samples in the blast constant temperature oven (or high-temperature furnace) that has been adjusted to the temperature specified by the product standard. Another painted panel was kept for comparison. After the specified time has elapsed, take out the painted sample, cool it to room temperature 25°C ± 1°C, and compare it with a previously left painted sample to check whether it has peeling, wrinkling, bubbling, cracking, discoloration, etc. phenomenon or inspected according to the product standards, if not less than two samples can meet the requirements of the crystal production standard as qualified.
2. Determination of abrasion resistance of coating film
The wear resistance of the coating film can be measured by the method in the national standard CB1768-79 "Determination of the Abrasion Resistance of Paint Films". This standard applies to the determination of the abrasion resistance of paint films. A paint film abrasion Tester is used to express the weight loss (g) of the paint film after a specified number of abrasions under a certain load.
(1) Materials and equipment
Glass plate (JG40-62): 3mm thick, 100mm in diameter, and a small hole with a diameter of 9mm in the center.
Balance: Sensitivity is 0.00lg.
Paint film abrasion Tester: JM-1 type.
sand wheel dresser
Rubber grinding wheel: JM-100, JM-120, thickness 10mm, diameter 50mm.
(2) Measurement method
According to GB1727-79 "General Preparation Method of Paint Film", apply the reduced sample brush to spray on the clean and dry bottom plate. Apply the second coat 24 hours after the first coat of the self-drying paint, and dry for 48 hours for the test. After the first coat of volatile paint dries for 2 hours, spray the second coat, and after the last coat, let it dry for 24 hours to test.
Fix the sample plate on the working plate of the wear-resistant instrument, add the required load on the pressing arm (the self-weight of the pressing arm is 200g should be counted) and the refurbished rubber grinding wheel, and add a load equal to the weight of the grinding wheel at the end of the tube. Gently put down the housing tube with the balance weight. Put down the vacuum nozzle, and adjust it to 1~1.5mm away from the model. Turn on the main switch, the vacuum cleaner switch, and the turntable switch in sequence. Grind the template for 50 revolutions first to form a relatively flat surface. Turn off the power and take out the model. Gently wipe off the scum with a brush and weigh (accurate to 0.00lg).
Follow the product standard to adjust the counter for testing. When the required number of wear-resistant revolutions is reached, it will stop immediately. Take out the model, wipe off the scum, weigh it, and the difference between the quality before and after is the weight loss of the paint film.
The test was carried out under constant temperature and humidity conditions.
Parallel test twice, each time the difference between the average value is not more than 7% of the average value, the arithmetic mean of the results.
