ISO 12944-E Circuit Board Kit

In the ISO 12944 standard system, ISO 12944 is divided into 8 parts (ISO 12944-1 to ISO 12944-8

1. Parameters of the coating system composition
   • Primer: It usually requires good adhesion and anti-rust performance. For example, zinc-rich primer has strong adhesion to the metal surface and can provide cathodic protection. The zinc powder content is generally above 80% (by mass), and the dry film thickness is generally 60 – 80 micrometers.
   • Intermediate coat: Its main function is to increase the coating thickness, improve the shielding performance and mechanical properties. A common epoxy micaceous iron oxide intermediate coat has a micaceous iron oxide pigment content of generally 30% – 40%, and the dry film thickness is usually 100 – 150 micrometers.
   • Topcoat: It is required to have good weather resistance, decorative properties, and chemical resistance. For example, acrylic polyurethane topcoat has good weather resistance and can maintain color and gloss outdoors for a long time. The dry film thickness is generally 40 – 60 micrometers.
2. Coating performance parameters
   • Adhesion: According to the standard test method (such as the pull-off method, etc.), the adhesion between the coating and the steel surface generally requires reaching above 5MPa (the specific value may vary according to different application scenarios and standard requirements).
   • Impact resistance: The falling weight impact test is usually adopted, and the coating should not crack or peel off under a certain impact energy (such as 50cm·kg).
   • Flexibility: It is evaluated through the bending test. The coating should not crack after being bent at the specified bending diameter (such as 3mm or 5mm).
   • Salt spray resistance: Place the coated specimen in a salt spray test chamber, and conduct the test according to the specified salt spray concentration (generally a 5% sodium chloride solution) and test time (such as 500h, 1000h, etc.). The coating should have no obvious corrosion, blistering, peeling, etc.
   • Damp heat resistance: Conduct the test under the specified temperature (such as 40°C) and humidity (such as 95%). After a certain period of time (such as 500h), the coating should have no obvious changes.
3. Matching parameters: There needs to be good compatibility between different primers, intermediate coats, and topcoats. For example, an epoxy primer is generally matched with an epoxy intermediate coat, and an acrylic polyurethane topcoat is usually matched with an epoxy intermediate coat to ensure the adhesion between the coatings and the overall performance.