Critical Pigment Volume Concentration (CPVC)

Definition - What does Critical Pigment Volume Concentration (CPVC) mean?

Critical pigment volume concentration (CPVC) refers to a scientific property used to describe the volumetric point at which there is precisely enough polymer to provide moisture to the finely ground particles of pigment that are used to make paint. These pigment particles are instrumental in preventing corrosion for metallic substrates.

Corrosionpedia explains Critical Pigment Volume Concentration (CPVC)

Critical pigment volume concentration (CPVC) is an integral part of every paint or pigment system. It is usually described in the numerical range of 30% - 60%, and is the amount of pigment that can be added to a polymer to provide optimum protection and color profile. Corrosion resistance, paint film properties and metallic reactivity to acid exposure are all properties that can be predicted with this ratio.

It should be noted that CPVC does not apply to dyes. The distinction between pigments and dyes is generally made on the basis of solubility; pigments are insoluble and dispersed in the material, while dyes are soluble or in solution when used.

For most systems, corrosion resistance is affected significantly by the PVC/CPVC ratio. The optimum percentage of inhibitive pigment for each system must be established prior to pigment use.

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