Question 1

What is the difference between substrate wetting and dispersing wetting?

Accepted Answer

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.

Question 2

Which substrates require special wetting agents?

Accepted Answer

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.

Question 3

How do I test whether a wetting agent is performing correctly?

Accepted Answer

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.

Substrate Wetting Chemicals

Acetylenic Diol Wetting Agent Surfynol 420 Type

Acetylenic Diol Wetting Agent Surfynol-104 Type (Low Foam)

Acetylenic Diol Wetting Agent Surfynol-420 Type (EO-Modified)

Alkyl Polyglucoside Surfactant APG-810

Amphoteric Dispersant AD-200

Cationic Dispersant for Carbon Black CDC-10

Dioctyl Sodium Sulfosuccinate OT-75 (Low-Foam Wetting Agent)

Dioctyl Sodium Sulfosuccinate Wetting Agent OT-75

Fatty Alcohol Ethoxylate AEO-9

Fatty Alcohol Ethoxylate AEO-9 (HLB≈13, Nonionic)

Fluorocarbon Surfactant Leveling Agent (Ultra-Low Surface Tension)

Gemini Surfactant Dispersant 12-2-12

Hyperdispersant for Organic Pigments HP-2000

Low-Foam Nonionic Wetting Agent LFW-2

Low-MW Polyacrylate Dispersant PAD-30

Modified Acrylic Dispersant for Organic Pigments DAP-60

Nonionic EO/PO Block Copolymer Dispersant NEP-10

Phosphate Ester Dispersant PE-8

Polyether Phosphate Wetting Dispersant PEPD-20

Polyether Silicone Substrate Wetting Agent BYK-346 Type

Polyether Silicone Wetting Agent BYK-341 Type (Waterborne)

Polysorbate 80 (Tween-80)

Silicone-Polyether Block Copolymer Gemini Type (Bifunctional)

Sodium Hexametaphosphate Dispersant SHMP

Frequently Asked Questions — Substrate Wetting Chemicals

Looking for specific raw materials?