SemiSIL R272: Hydrophobic Fumed Silica (DDS Treated)
SemiSIL R272 is a high-performance DDS treated fumed silica (Dimethyldichlorosilane treated) optimized for moisture-sensitive formulations. By precisely reducing surface silanol density, R272 acts as a superior long shelf-life thixotropic agent, preventing viscosity drift in RTV silicone sealants and ensuring permanent pigment suspension in high-end printing inks.
Quick Profile
- Surface Treatment: DDS (Dimethyldichlorosilane)
- Surface Area (BET): 110 ± 20 m²/g
- CAS Number: 112945-52-5
- Carbon Content: 0.6% - 1.2%
- Key Advantage:Superior RTV sealant stability, extended shelf-life protection, and optimized rheology control for printing inks.
Strategic Applications & Solutions
RTV Silicone Sealants
The industry-standard hydrophobic silica for RTV silicone sealant. It ensures a long shelf-life by preventing viscosity drift and maintaining stable thixotropy in the tube.
Adhesives & Sealants
Delivers precise rheology control for RTV-T adhesives. It provides excellent non-sag properties and reinforcement for construction and industrial bonding.
Printing Inks
Functions as a specialized anti-settling agent for printing inks. It keeps pigments in permanent suspension while ensuring optimal flow during high-speed printing.
Powder Coatings
Serves as a high-performance free flow aid for powder coatings. It protects particles from moisture-induced clumping and improves fluidization in spray booths.
Key Functional Properties of SemiSIL R272
Shelf-Life Stabilization
As a premier DDS treated fumed silica, it effectively reduces surface silanol density, preventing the thickening of RTV sealants during storage and ensuring a consistent 24-month shelf-life.
Superior Rheology Control
This DDS treated fumed silica builds a stable thixotropic network in silicone fluids, providing the necessary body and structure for non-slump adhesives and printing inks.
Hydrophobic Moisture Resistance
With controlled carbon content (0.6%~1.2%), this DDS treated fumed silica minimizes water absorption ($\leq 0.5\%$), protecting moisture-curable systems from premature skinning or hardening.
Mechanical Reinforcement & Anti-Settling
SemiSIL R272 functions as a high-efficiency DDS treated fumed silica filler, delivering unmatched tear strength in elastomers while maintaining pigment suspension in high-end coatings and inks.
Technical Data (TDS)
| Property | Standard Value | Unit | Method |
|---|---|---|---|
| Specific Surface Area (BET) | 100 ± 20 | m²/g | GB/T 20020 |
| pH Value (in 4% dispersion) | 4.0 ~ 7.0 | - | GB/T 20020 |
| Carbon Content | 3.5 ~ 5.5 | Wt% | GB/T 20020 |
| Loss on Drying (2h @ 105°C) | ≤ 0.5 | Wt% | GB/T 20020 |
| Loss on Ignition (2h @ 1000°C) | ≤ 2.0 | Wt% | GB/T 20020 |
| Tamped Density | 40 ~ 60 | g/L | GB/T 20020 |
| Silica Content (SiO₂) | ≥ 99.8 | % | GB/T 20020 |
Packaging & Logistics
Non-DG Compliance: Fully safe for Railway, Sea (Shipping), and Truck transportation.
20'FCL Loading
• 180kg / pallet (18 bags)
• 10 pallets / 1600kg total
• 10 pallets / 1600kg total
40'HQ Loading
• 220kg / pallet (22 bags)
• 20 pallets / 4400kg total
• 20 pallets / 4400kg total
Common Questions about DDS Treated Fumed Silica R272
Is SemiSIL R272 a direct technical equivalent to Aerosil® R972?
Yes. SemiSIL R272 is a 1:1 technical replacement for standard DDS-treated hydrophobic fumed silica grades. It matches the surface area and carbon content specifications required for RTV silicone sealants and industrial coatings, ensuring a seamless drop-in transition.
Why is R272 the preferred choice for RTV silicone sealant shelf-life?
SemiSIL R272 is a specialized long shelf-life thixotropic agent. Because it is treated with DDS (Dimethyldichlorosilane), it significantly reduces surface hydroxyl density, preventing the thickening and "viscosity drift" common in moisture-curable sealants during storage.
How does R272 improve the non-slump properties of RTV-T adhesives?
R272 builds a strong 3D physical network in silicone fluids. This provides superior rheology control for RTV-T adhesives, ensuring that the sealant stays in place on vertical joints without sagging, even at high application temperatures.
Can R272 prevent pigment settling in printing inks?
Absolutely. R272 acts as a high-efficiency anti-settling agent for printing inks. Its hydrophobic surface prevents pigment agglomeration, ensuring that color consistency and flow properties are maintained even in low-viscosity ink formulations.
What is the difference between R272 (DDS) and R202 (PDMS) treated silica?
The difference between PDMS and DDS treated silica is primarily the carbon load and application focus. DDS treated fumed silica (R272) has lower carbon content ($0.6-1.2\%$), making it more economical and effective for RTV sealants, while PDMS (R202) is designed for extreme hydrophobicity and anti-structuring in rubber.
Factory-Direct hydrophobic fumed silica R272
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