The test sample is in sulfur dioxide Observe the surface in the atmosphere after a certain period of time gloss And other characteristics. two point one Sulfuric acid: chemically pure.
two point two Anhydrous sodium sulfite : Chemically pure. three point one Balance: the maximum weight is 200g, and the sensitivity is 10mg.
three point two Oven: from room temperature to 200 ℃.
three point three Reaction vessel: a square glass cylinder with a depth of more than 240mm, with an air inlet and an air outlet respectively 20-30mm from the upper opening and the bottom, with a sample rack inside and a grinding cap on it.
The sample size is 80mm × 60mm × 10mm, polished on both sides or one side. Take 4 samples with bedding, 4 samples with parallel and vertical bedding, 4 samples without bedding, 3 of which are used for acid resistance test, and 1 for comparison. Measure and record the gloss of each sample.
five point one Place the sample in an oven at 105 ± 2 ℃, dry it for 24h, take it out, put it in a dryer to cool to room temperature, and weigh the mass (m zero ）。
five point two Generated according to the following reaction sulfur dioxide , pass sulfur dioxide into distilled water To prepare sulfur dioxide solution. Na two SO three +H two SO four →Na two SO four +H two O+SO two ↑
SO two +H two O=H two SO three
five point three Inject 1900mL distilled water into the reaction vessel, put it into the sample rack, place the samples on the rack at a distance of 10mm, cover the vessel cover, and inject sulfur dioxide into the water from the lower opening. Drop about 100g of sulfur dioxide, close the lower mouth, place it at room temperature for 14d, take it out, observe the surface change, dry it, cool it to room temperature, and weigh (m one ）Replace with a new sulfur dioxide solution according to the above steps, place it for another 14 days, take it out, observe the surface changes, dry it, cool it to room temperature, and weigh it (m two ）。
Relative mass change after 14d ［ m ］ fourteen (%)] and relative mass change after 28 days [m twenty-eight (%)] calculated according to the following formula:
m fourteen = ×100%…………………………(1) m twenty-eight = ×100% …………………………(2) Where: m zero ——Mass of sample without acid corrosion, g;
m one ——Mass after 14 days of acid corrosion, g;
m two ——Mass after 28d corrosion, g.
Record m fourteen 、m twenty-eight The average value of. After the test is completed, report the changes of gloss and other characteristics, and observe whether the coating has swelling, peeling and falling off, and record the results on the acid resistance test report.
