Name: Anti-Sag Rheological Additive AC-410 (BYK-410 Type)
Brand: Coatingsink
SKU: anti-sag-additive-byk-7410-et
Availability: InStock

Question 1

How does a urea-modified anti-sag additive differ from fumed silica or organoclay?

Accepted Answer

Urea-modified anti-sag additives (BYK-410 type) form a strong, recoverable physical network in the coating through hydrogen bonding between urea groups, creating very pronounced thixotropy with a high yield point and rapid viscosity recovery after shear. This gives excellent sag resistance at high WFT (wet film thickness ≥200 µm) without the grinding energy or pre-gelling steps required for organoclay, and without the dustiness and agglomeration issues of fumed silica. They are particularly effective in solvent-borne and high-solids systems and compatible with polyurethane and epoxy binders.

Question 2

At what stage should AC-410 be added to the coating formulation?

Accepted Answer

This additive should be added to the mill base or grind phase when high shear is applied, which ensures thorough distribution and breaks up any initial agglomerates. Alternatively, it can be added during the let-down phase with moderate agitation, provided adequate mixing time (≥15 min) is given for the urea network to fully reform. Adding at the very end with minimal mixing typically results in incomplete network development and poor sag resistance. Best practice: add at 50–60°C in hot-mix processes to accelerate dissolution, then allow to cool before evaluating viscosity.

Carrier	diethylene glycol monoethyl ether
Appearance	clear viscous liquid
Solid Content	52% (active)
Viscosity (25°C)	1000–3000 mPa·s
Recommended Dosage	0.3–1.5%

Anti-Sag Rheological Additive AC-410 (BYK-410 Type)

Specifications

FAQ

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