Selection of coating thickness of color-coated rolls

Summary: From a microscopic point of view, the coating is a porous organization. Water in the air and corrosive media (chloride i...
From a microscopic point of view, the coating is a porous organization. Water in the air and corrosive media (chloride ions, etc.) will invade through the weak part of the coating, causing corrosion under the film, and then the coating will bubble and peel off.

In addition, even with the same coating thickness, the secondary coating is denser than the primary coating. According to foreign reports and related corrosion test results, the front coating of 20μm or more can effectively prevent the intrusion of corrosive media. Because the anti-corrosion mechanism of primer and topcoat is different, not only must the total film thickness be specified, but also the primer (≥ 5μm) and the thickness of the topcoat (≥15μm). Only in this way can the corrosion resistance of different parts of the color-coated steel sheet be balanced.

PVDF products require a thicker coating film because they have to provide a longer service life guarantee. The requirements for the backside coating depend on the application. The sandwich panel only requires one layer of bondable primer, and the formed steel plate is also required to be coated with two layers due to the corrosive indoor environment, with a thickness of at least 10μm or more.

Zhejiang Tainnv Color Steel Co., Ltd. was established in January 2003, located in Zhejiang Province, which is a Sino-Hong Kong joint venture with a registered capital of 50 million RMB. The company covers an area of 50000㎡, and a workshop area of 12000㎡. Company’s main products are hot galvanized steel coil, aluzinc coil, prepainted steel coils (PPGI / PPGL), prepainted aluminum coil, printed PPGI for household appliance, roofing/corrugated PPGI sheet, and PPGI paint. Currently, we have 85 skilled employees, 5 professional engineers and 15 experienced office personnel. The manufacture capability of our production line is nearly 100,000 metric tons per year.

Our company produces high quality color coated steel, and imposes strict quality control over the prepainted steel coils. We use good quality hot-dip galvanized steel coils or Alu-Zinc coated steel coils as base sheet and strictly select coated paints, which have won public praise in China. Moreover, we have attained ISO9001 certification, which gives quality promise to customers and competitive advantage for our company.