Mojado de Sustratos Productos Químicos
Los agentes humectantes de sustratos reducen la tensión superficial de las formulaciones de recubrimiento para permitir una propagación uniforme en sustratos de baja energía como plásticos, metales aceitosos y superficies minerales. Previenen el encogimiento, la formación de cráteres y los poros mediante la garantía de un mojado completo antes de la formación de película.
Preguntas Frecuentes — Mojado de Sustratos Productos Químicos
What is the difference between substrate wetting and dispersing wetting?
Substrate wetting agents reduce the dynamic surface tension of the liquid coating to match or fall below the critical surface energy of the substrate, enabling complete wet-out. Dispersing wetting agents (like polymeric dispersants) wet the pigment surface during the dispersion process. Both mechanisms involve surface tension reduction, but they target different interfaces — substrate surface vs. pigment surface.
Which substrates require special wetting agents?
Low-energy substrates present the greatest challenge: polyolefins (PP, PE) at 29–31 mN/m, PTFE at 18 mN/m, and silicone-contaminated surfaces. Standard waterborne coatings have surface tensions of 45–60 mN/m — far above the substrate critical surface energy — without additives. Silicone wetting agents (polydimethylsiloxane derivatives) reduce coating surface tension to 20–25 mN/m; fluorinated wetting agents achieve 15–18 mN/m.
How do I test whether a wetting agent is performing correctly?
Standard tests include: contact angle measurement on the substrate (target < 10° for complete wetting), dynamic surface tension with bubble pressure tensiometer at coating application speed, and drawdown panels on the substrate checking for crawling, fisheyes, or pinholes. Water spotting on dried film indicates insufficient crosslink density, not wetting failure. Foam testing is also needed since many wetting agents also foam.
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