Name: Hydroxyl-Functional Silicone Fluid HSF-50
Brand: Coatingsink
SKU: hydroxyl-silicone-fluid-hsf50
Availability: InStock

Question 1

What crosslinking mechanisms are compatible with HSF-50?

Accepted Answer

HSF-50 terminal hydroxyl groups react with isocyanates (urethane linkage), acid anhydrides (ester linkage), and undergo silanol condensation under tin or titanium catalysis, making it suitable for one- and two-component silicone sealant and silicone-modified coating systems.

Question 2

How does the Mn ~50,000 molecular weight affect network properties?

Accepted Answer

At Mn ~50,000 g/mol the chain length delivers a low crosslink density after cure, yielding high elongation (>300%) and excellent low-temperature flexibility. This makes HSF-50 well suited to construction joint sealants and flexible protective topcoats where movement accommodation is required.

Question 3

At what loading level should HSF-50 be incorporated in a silicone-modified PU coating?

Accepted Answer

Typical loading is 10–25 wt% of total binder solids. Below 10% the hydrophobicity and slip benefit are marginal; above 30% cure density may drop and adhesion to polar substrates can be compromised. Stoichiometry should account for HSF-50 hydroxyl equivalents when calculating the NCO index.

Appearance	Colorless to pale yellow clear liquid
Hydroxyl Content	0.05–0.08 mmol/g
Viscosity (25°C)	8,000–12,000 mPa·s
Refractive Index (25°C)	1.403
Number-Average Molecular Weight	~50,000 g/mol

Hydroxyl-Functional Silicone Fluid HSF-50

Specifications

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