Dr E. Ramanathan Phd | Paint Consultant
SaitechAI Paint Formulator includes:
- P/B Ratio
- PVC (multi-component)
- CPVC Estimator (oil-absorption method)
- Gloss & Porosity Predictor (from PVC vs CPVC)
- DFT ↔ WFT
- Coverage (m²/L)
- VOC (by solvent list or by solids & density)
- Batch Scaling & BOM
- Cost per kg / per L
Essential Toolkit for Paint Formulators
Paint Formulator’sToolkit
SaitechAI Concept Card — Paint Formulation Essentials
Formulas + significance for key formulation parameters used in coatings R&D and production.
1) Pigment–Binder Ratio (P/B)
Balances hiding power vs. film strength & adhesion.
Formula
P/B = Wpigments ÷ Wbinder solids
- Higher P/B → opacity & tint strength ↑; too high → chalking/poor adhesion.
- Lower P/B → better cohesion & gloss; may reduce hiding & raise cost.
2) Pigment Volume Concentration (PVC)
Fraction of pigment volume within total non-volatile volume (multi-component).
Formula
PVC (%) = [ Σ (Wp,i / ρp,i) ] ÷ { Σ (Wp,i / ρp,i) + Σ (Wb,j / ρb,j) } × 100
where W = weight, ρ = density (g/mL) for pigments (p) & binders (b)
- Key driver of gloss, permeability, scrub, mechanical strength.
- Densities matter: TiO₂ ≠ CaCO₃ ≠ resin solids.
3) CPVC Estimator (Oil-Absorption method)
Critical PVC where binder just fills voids around pigments.
Formula (approx.)
CPVC ≈ ( OA × ρb ) ÷ ( OA × ρb + 1 ) × 100
where OA = mL oil / 100 g pigment; ρb = binder density (g/mL)
- Below CPVC → denser films, higher gloss; near CPVC → matte onset; above → porous/chalking.
- Use as screening; verify via gloss, water perm, scrub tests.
4) Gloss & Porosity Predictor (PVC vs CPVC)
Quick qualitative indicator from PVC/CPVC ratio.
Ratio
R = PVC ÷ CPVC
- R ≪ 1 → high gloss, low porosity
- R ≈ 1 → semi-matte, rising porosity
- R > 1 → matte/flat, high porosity, chalking risk
5) DFT ↔ WFT (Dry ↔ Wet Film Thickness)
Links applied wet film to final dry film based on volume solids.
Formulas
WFT = DFT ÷ VSfrac
DFT = WFT × VSfrac
(If spray) Applied WFT ≈ (DFT ÷ VSfrac) ÷ TEfrac
- VSfrac = volume solids / 100; TEfrac = transfer efficiency / 100.
- DFT drives durability & corrosion resistance; WFT guides applicators.
Units: DFT/WFT in µm (1 mil = 25.4 µm)
6) Coverage (m²/L)
Theoretical spreading rate at target DFT and volume solids.
Formula
Coverage (m²/L) ≈ [ VS(%) × 10 ] ÷ DFT(µm)
- Practical coverage is lower due to profile, overlap, waste, and method.
- Use for label claims and application guidance.
7) VOC (Volatile Organic Compounds)
Regulatory metric of volatiles emitted (g/L).
Mode A — by solvent mass
VOC (g/L) = [ Σ Msolvent (g) ] ÷ Vbatch (L)
Mode B — by paint density & NV%
VOC (g/L) ≈ ( ρpaint × 1000 ) × ( 1 − NV%/100 )
- Compares against BIS/ASTM/EU/EPA limits; crucial for eco-labels.
- Assumptions: volatiles ≈ solvents; adjust if reactive diluents/moisture present.
8) Batch Scaling & BOM
Convert parts-by-weight lab recipe to any batch size; generate production sheet.
Formula
Wi = ( Pi ÷ ΣP ) × Wtotal
- Keeps ratios constant across lab → pilot → plant.
- Feeds purchasing, scheduling, and QC sampling plans.
9) Cost per kg / per L
Economics for pricing & margin control.
Formulas
Cost/kg = Σ ( Wi × Ci ) ÷ Wtotal
Cost/L = (Cost/kg) × ρpaint
- Decoratives: Cost/L aligns with coverage value; industrial: Cost/kg often used.
- Include overheads (energy, packaging, QA) in commercial pricing.
