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Oct 28, 2025
The impact of solid content on coating weight is one of the core relationships in the coating process, directly determining coating consumption, cost control, and coating performance.
Below is a systematic analysis, combining data and process logic to explain its impact mechanism and optimization paths:

1. Core Relationship Formula

Dry film coating weight = Wet film coating weight × Solid content

Example:

  • Target dry film coating weight: 20g/m²
  • If solid content is 50% → Required wet film coating weight = 20 / 0.5 = 40g/m²
  • If solid content is 70% → Required wet film coating weight = 20 / 0.7 ≈ 28.6g/m²
Conclusion: Higher solid content reduces the wet film coating weight required to achieve the same dry film thickness.

2. Three Key Impact Dimensions of Solid Content on Coating Weight

2.1 Coating Consumption and Cost

Solid Content Wet Film Coating Weight (for 20g/m² target dry film) Solvent Cost Change (Benchmark: 50% solid content)
40% 50g/m² +25% increase
50% 40g/m² Benchmark
65% 30.8g/m² -23% decrease
80% 25g/m² -37.5% decrease
✅ Economic Benefit: Increasing coating solid content can significantly reduce manufacturing costs. For every 10% increase in solid content, the coating consumption per unit area decreases by approximately 12–15%.

2.2 Coating Process Window

① Low Solid Content

  • Excessively thick wet film may cause sagging and uneven drying (solvent residue, resulting in rainbow marks, etc.).
  • Coating speed is limited.

② High Solid Content

  • Thinner wet film allows higher coating speed.
  • Risk: Increased viscosity may lead to reduced transfer efficiency and poor coating leveling.
✅ Risk Control: Adjustments to solid content must be aligned with actual process performance.

2.3 Coating Performance and Defects

① High Wet Film Coating Weight (due to low solid content)

  • High drying shrinkage stress → Coating cracking/edge lifting.
  • Long solvent migration path → Rainbow marks, pinholes, and residual bubbles.

② Insufficient Dry Film Coating Weight (due to high solid content)

  • Inadequate dry film thickness → Reduced barrier properties/wear resistance (e.g., protective films).
  • Short leveling time → Orange peel texture and roller marks (leveling agents may be added for compensation).

3. Key Process Contradictions and Solutions

Contradiction: High solid content saves coating material, but increased viscosity raises the difficulty of coating weight control.
Problem Phenomenon Mechanism of Occurrence Solution
Sudden drop in transfer efficiency High-viscosity coating struggles to release from mesh holes/roller surfaces Change coating method (e.g., switch from two-roller coating to reverse gravure coating)
Coating weight fluctuation (±10% or more) Viscosity is sensitive to temperature, leading to unstable rheology Constant-temperature feeding system (temperature control: ±1℃) + online closed-loop viscosity control
Thick edges, thin center Poor leveling of high-viscosity coating Add auxiliary leveling device after coating

Conclusion

  • Solid content and coating weight are the core fulcrums of the "cost-quality-efficiency" triangle.
  • Economics: Higher solid content → Lower coating weight → Lower cost.
  • Stability: When adjusting the solid content of existing coatings, continuous monitoring of product stability is required.
  • Trend: High-end fields are moving toward higher solid content, relying on collaborative innovation in equipment and formulations.
Topwin is one of the leading professional manufacturers and solution providers with more than 20 years of experience, and has domestic top-level engineers in the silicone surfactant industry. Specializing in research and development, production, sales, and marketing of silicone-based special functional performance materials, Topwin also serves as a professional provider of technical services. Now our products are widely used in Polyurethane Foam, Corp Protection, Coatings and InksLeather & Textile, Silicone Release Coating for Paper and Film, Personal Care,  and others.