
ASTRA WA®
Wetting Agents
Substrate wetting agents. Significantly reduce surface tension, prevent craters, improve flow and leveling. Some grades also have defoaming properties.
Why use substrate wetting agents?
When a coating cannot properly wet the substrate, it forms craters, fisheyes and dewetting defects. Wetting agents dramatically lower surface tension so the coating spreads evenly across difficult substrates like plastics, metals contaminated with oil, and low-energy surfaces.

Key Benefits
- Significant surface tension reduction
- Crater and fisheye prevention
- Better flow and leveling on difficult substrates
- Some grades also defoam
- Compatible with solvent, water and UV systems
- Improves edge coverage on sharp features
Impact on Coating Performance
ASTRA WA agents eliminate the most frustrating defects on contaminated or low-energy substrates. The result: cleaner finishes, lower reject rates and higher production yields.
O – organosoluble, WB – water-based, RC – radiation-curable
Product Catalog
Download TDS| Active % | Feature | TDS | Samples | |||
|---|---|---|---|---|---|---|
| ASTRA WA-1003 | BYK-345 | Water-based / Radiation-curable | 100% | Provides excellent substrate wetting and leveling for water systems. Stable in water, does not cause foam. | ||
| ASTRA WA-103 | Surfynol-104E | Water-based | 50% | Suitable for water systems, excellent substrate wetting, works as a defoamer, influences chemical surface tension. | ||
| ASTRA WA-1103 | BYK-346 | Water-based / Radiation-curable | 50% | Significantly reduces surface tension, ensures substrate wetting, does not affect the possibility of paint coating overlap, and is resistant to hydrolysis. | ||
| ASTRA WA-1203 | BYK-347 | Water-based / Radiation-curable | 100% | Reduces the surface tension of the system, ensures excellent wetting of the substrate. | ||
| ASTRA WA-1303 | Surfynol-465 | Water-based | 100% | Affects dynamic surface tension, high hydrophilicity, perfectly wets the substrate, prevents cratering, improves leveling, does not stabilize foam. | ||
| ASTRA WA-1403 | BYK-348 | Solvent-based / Water-based / Radiation-curable | 100% | Suitable for water and UV curing systems. Provides rapid leveling, significantly reduces surface tension. Works in a wide temperature range. Resistant to hydrolysis. | ||
| ASTRA WA-1503 | BYK-349 | Water-based | 100% | Can significantly reduce surface tension, provides substrate washing. Does not stabilize foam. | ||
| ASTRA WA-1603 | Tego-Twin 4000 | Water-based / Radiation-curable | 100% | Reduces the surface tension of the system, ensures wetting of the substrate, does not stabilize foam and has anti-foam properties. | ||
| ASTRA WA-1703 | Tego-Twin 4100 | Water-based / Radiation-curable | 100% | Reduces surface tension of the system, ensures substrate wetting, does not stabilize foam. Used for industrial water-based paints and varnishes and UV-curable systems. | ||
| ASTRA WA-1803 | Tego-270 | Solvent-based / Water-based / Radiation-curable | 100% | Reduces the surface tension of the system, ensures wetting of the substrate, does not stabilize the foam. |
Articles about ASTRA WA®

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Avoid Six Week Recoat Failures with Astra R&D Defoamers for Formulators
When recoatability is the binding constraint, non-silicone defoamers or very low-dose, engineered polysiloxanes outperform conventional silicone chemistries because they minimize surface migration and intercoat contamination. The second lever is process control: incorporation shear, droplet or particle loading, and the add point (millbase versus let-down) determine whether a chemically sound defoamer behaves well in production. We recommend validating both choices with ISO-style recoat testing before scale-up.
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