Pigment volume concentration (PVC) of paint is defined as:
What is Pigment Volume Concentration (PVC)?
Pigment Volume Concentration (PVC) is a critical parameter in paint formulation. It describes the composition of the dry paint film—the part that remains on the surface after all the volatile solvents have evaporated. Specifically, PVC is the ratio of the volume of solid pigments (and fillers) to the total volume of the dry film (pigments + non-volatile binder). This ratio significantly influences the paint's properties, such as gloss, permeability, and durability.
📝 Detailed Analysis of the Options
The key to this question is understanding what "non-volatile constituents" are. These are the components that do not evaporate and form the final, solid paint layer. They consist of:
- Pigments and Fillers ($V_p + V_f$): The solid particles that provide color and body.
- Non-volatile Binder ($V_b$): The part of the liquid vehicle that hardens to form the film.
The formula for PVC is:
Option A: $$ \frac{\text{Volume of pigment in paint}}{\text{Total volume of non-volatile constituents of paint}} $$
Analysis: This option correctly identifies the formula for PVC. The numerator ("Volume of pigment") represents all solid particles ($V_p + V_f$), and the denominator ("Total volume of non-volatile constituents") represents the entire dry film ($V_p + V_f + V_b$).
Conclusion: This is the correct definition.
Option B: Volatile constituents in denominator
Analysis: This is incorrect. Volatile constituents (solvents/thinners) evaporate and are not part of the final paint film. PVC is a measure of the dry film's composition.
Options C & D: Incorrect numerators
Analysis: These options use incorrect numerators. Option C only considers the base, ignoring other pigments and fillers. Option D uses the volume of the vehicle (the liquid part), which is incorrect as PVC measures the ratio of solids within the dry film.
📊 Typical PVC Values for Different Coatings
| Type of Coating | Typical PVC (%) | Characteristics |
|---|---|---|
| Automotive Clear Coat | < 5% | Very high gloss, transparent, maximum binder. |
| High Gloss White Top Coat | 15 – 25% | High gloss, good durability, more binder than pigment. |
| Anti-Corrosion Primer | 25 – 65% | Matt/Satin finish, balanced pigment for protection. |
| Interior Matt Wall Paint | > 85% | Very matt, porous, high pigment content for hiding power. |