Whether the conductive primer can improve the electrostatic spraying of non-metallic workpieces should not only look at "whether there is a spray primer", but also can not only look at a surface resistivity reading.What really requires closed-loop verification is: Effective connection between the continuous → dry film structure and the cured → surface/volume conductive path → and the grounding of → the hanger Charge attenuation behavior → Electrostatic field stability and coating transfer performance. There are four key judgments: Coating rate first refers to effective area coverage and continuity, not just paint consumption or average film thickness. Locally exposed bottoms, pinholes, thin edges, and uneven zoning will cause the conductive network to be cut off, and the electrostatic effect may be unstable even if the average film thickness seems to be acceptable. Surface resistivity is not the charge decay rate itself. The surface resistivity reflects the difficulty of conducting electricity along the coating surface; the charge decay time is also affected by the coating capacitance, area, film thickness, substrate, ground contact, temperature and humidity, and measurement structure. The effect of the degree of curing on the conductivity is usually not a monotonous relationship. Residual moisture or solvent during undercuring may cause temporarily low readings, but accompanied by drift, adhesion, and risk of re-coating; overcuring may also alter resin shrinkage, conductive filler contact, or interlayer adhesion.The specific direction must be confirmed by the corresponding primer system and test. “Lower resistance is better” is not a complete process goal. What is needed is to form a stable, uniform, repeatable discharge path from the spray area to the ground, while avoiding the illusion of localized silos, contact failures, and changes in test conditions. Therefore, the conductive primer
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