Description and features
SilQon HMTS (1,1,1,3,5,5,5-Heptamethyltrisiloxane) is a high-purity, reactive siloxane additive designed to enhance the stability and curing performance of moisture-sensitive formulations. Therefore it is ideal for use in polyurethane adhesives, sealants, and silane-modified polymers, it helps prevent moisture-related defects like foaming, gassing, and uneven curing.
By reacting rapidly with water, SilQon HMTS acts as an effective moisture scavanger, protecting reactive ingredients such as isocyanates and alkoxysilanes. It also supports crosslinking consistency in silane-based systems, improving appearance and end-use performance.
Availability
Europe: SilQon HMTS is in stock in our local warehouse.
We can also serve Canada, South America, South Africa, and other markets. Please contact our sales department for more details.
Key benefits
- Prevents foaming, bubbling, and gassing in PU systems
- Enhances curing consistency in silane-terminated adhesives
- Extends shelf life and improves batch-to-batch stability
- Helps reduce and haze in final products
This substance (CAS: 1873-88-7) has not yet been registered under REACH.
Product Identification
| CAS number | 1873-88-7 |
| EC number | 217-496-1 |
| Chemical name | 1,1,1,3,5,5,5-Heptamethyltrisiloxane |
| IUPAC name | 2,2,4,6,6-pentamethy-3,5-dioxa-2,4,6-trisilaheptane |
Specification
| Appearance | Liquid |
| Colour | Clear, Colourless |
| Refractive Index | 1.3790 ~ 1.3810 |
| Specific gravity | 0.8136 |
Recommended applications
- 1K and 2K Polyurethane adhesives & Sealants: Reduces moisture-triggered defects during application and curing.
- MS polymer and SMP systems: Binds free water to prevent pre-curing and extended storage stability.
- Silane-terminated binders: Promotes clean, uniform crosslinking and reduces surface issues.
- Hybrid epoxy-silane composites: Minimizes blushing and adhesion loss caused by ambient humidity
Packaging
Available packaging: 200 KG Drums.
Special packaging is available on request.
Storage
Initially, store SilQon HMTS in a tightly closed container in a dry, cool, and well-ventilated place. Furthermore, containers that are opened must be carefully resealed and kept upright to prevent leakage.
MSDS
A Material Safety Data Sheet (MSDS) is available for SilQon HMTS and all other products supplied by Vesta Chemicals BV.
An MSDS outlines the hazards of a product and explains how to handle, use, and store the product safely. Besides it provides important regulatory and emergency response information for the purchased product.
Molecular and structural information
| Molecular formula | C7H22O2Si3 |
| Molecular weight | 222.5 |
| Smiles notation | C[SiH](O[Si](C)(C)C)O[Si](C)(C)C |
| InChi key | QNWOFLWXQGHSRH-UHFFFAOYSA-N |
| Structural formula |  |
Physicochemical information
| Boiling point | 142° C (lit.) |
| Density | 0.819 g/mL at 25° C (lit.) |
| Flash point | 82 °F |
| Solubility | Chloroform (soluble), Methanol (slightly) |
| Vapor pressure (MGM) | 8.5hPa at 25° C |