Film property evaluation
The surface of the coating should smooth and smooth with good levelling; The film thickness shall meet the corresponding technical requirements and be stable :
- Physical properties, such as: hardness, adhesion, flexibility, impact strength, cupping
- Chemical properties, such as (1) corrosion resistance (single layer primer with phosphating treatment) ,(2) salt spray resistance ,according to ASTM method , quality product no less than 1200H ,(3) cyclic corrosion resistance ;more than 30 or 60 times , （4）edge corrosion resistance （or edge covering）
Construction performance evaluation
Both parties choose the best E-coating condition.
- Throwing power: under the same condition , the higher the better
- Heating and reduction: the film dried at 105℃ and 107℃ is weightless, the lower the thermal decomposition after high temperature drying, the better which is also conducive to environmental protection and the maintenance of the drying room
- Organic solvent in the tank: the lower the better under the premise of keeping the liquid stability . Modern index <1.0%. The trend is no organic solvent , which is conducive to environment protection.
- The stability of tank liquid: when normal producing , no need to add additives, can keep the tank liquid stable.
- Dryness of the film: From the viewpoint of energy saving ,curing temperature the lower the better, the shorter baking time (the holding time of film material ) is better.
- Intermedia coat compatibility , overcoatability: directly affect the adhesion and appearance of film, especially when E-coating primer, intermedia and finishing are not supplied from the same supplier.
Of course quality with good price , supplying guarantee, after-sales service those aspect is easy to understand, so we won’t explain it more