Silanes & Alkyl Silanes
Octadecyltrimethoxysilane (C18) | Manta L1831
Manta L1831 is n-octadecyltrimethoxysilane (CAS 3069-42-9), a C18 linear alkyl silane used in superhydrophobic and self-cleaning coatings, mineral filler treatment for polyolefins, pigment dispersion and semi-permanent mold release. Its long chain significantly reduces surface energy, and its methoxy groups hydrolyze rapidly to form durable covalent siloxane bonds with the substrate.
- Grade
- L1831
- Chemical Name
- Octadecyltrimethoxysilane
- CAS No.
- 3069-42-9
- EINECS
- 221-339-2
- Synonyms
- Trimethoxyoctadecylsilane
- Form
- Colorless clear liquid (May appear as a white waxy solid at temperatures below 17°C)
Overview
Manta L1831 is a monomeric long-chain alkyl functional silane, chemically identified as n-octadecyltrimethoxysilane. Its very long 18-carbon (C18) linear chain gives very high hydrophobicity and strong affinity for non-polar environments.
On exposure to moisture, the methoxy groups undergo rapid hydrolysis and form durable, covalent siloxane bonds with the substrate, while the long C18 chain extends outward to create a dense, highly water-repellent protective layer. Its high molecular weight gives virtually no volatility and good thermal stability.
L1831 is particularly suited to superhydrophobic surfaces, heavy-duty mineral filler treatments for polyolefins and the surface modification of submicron or nano-particles. It has a longer alkyl chain than Manta L1631, the C16 grade, and it can solidify at low temperatures, so it may need gentle warming before use.
Key Features
- 18-carbon linear chain for very high hydrophobicity and lipophilicity
- Significantly reduces surface energy
- Rapid methoxy hydrolysis and covalent siloxane bonding to the substrate
- Virtually no volatility and good thermal stability
- Surface modification of submicron and nano-particles
- Liquid that can solidify to a white waxy solid at low temperatures
Specifications
| Property | Typical Value |
|---|---|
| Appearance | Colorless clear liquid (May appear as a white waxy solid at temperatures below 17°C) |
| Purity (by GC, %) | 92.0 min |
| Density (ρ20°C, g/cm³) | Approx.0.883 |
| Refractive Index (nD 25°C) | Approx.1.438-1.440 |
Typical values from the current Technical Data Sheet.
Applications
- Mineral filler treatment: surface modifier for inorganic fillers such as ATH, MDH and silica in polyolefins, reducing melt viscosity, improving processability and maintaining mechanical strength in highly loaded compounds
- Superhydrophobic coatings: superhydrophobic (lotus effect) and self-cleaning coatings with long-lasting water repellency on concrete, glass and ceramics
- Pigment dispersion: helps to limit the agglomeration of ultrafine pigments such as TiO2 and nanoparticles, giving rapid wetting, good dispersion and higher color strength in masterbatches and industrial coatings
- Mold release: thermally stable, semi-permanent release agent in plastic and rubber molding processes
Related applications: Concrete, Masonry & Stone Protection · Paints & Coatings · Plastics & Masterbatches
Packaging & Storage
Supplied in 20 kg pail, 180 kg drum and 900 kg IBC.
Safety and Storage
Phase Change (Melting/Freezing): Manta L1831 has a melting point of approximately 16–17°C. If solidified during winter transport or storage, gently warm the container in a warm water bath or temperature-controlled room until fully liquefied. Do not use an open flame.
Hydrolysis Reaction & Methanol Release: Manta L1831 reacts with moisture to form cross-linked polysiloxanes. CRITICAL WARNING: This hydrolysis reaction releases METHANOL as a toxic and highly flammable byproduct. Ensure excellent local exhaust ventilation during formulation and application to prevent vapor accumulation.
Storage Conditions: Store in a cool, dry, and well-ventilated area away from direct sunlight and moisture. Keep containers hermetically sealed.
Shelf Life & Transport: 12 months shelf life. Classified as a non-hazardous substance for transport.
Documents
- Technical Data Sheet · PDF Download TDS
- SDS and COA · on request Request Documents
Frequently Asked Questions
What should I do if Manta L1831 arrives solidified in cold weather?
L1831 can solidify at low temperatures; its specified appearance is: Colorless clear liquid (May appear as a white waxy solid at temperatures below 17°C). If it has solidified during winter transport or storage, gently warm the container in a warm water bath or a temperature-controlled room until fully liquefied. Do not use an open flame.
How does L1831 enable superhydrophobic 'lotus effect' coatings?
Its long octadecyl group significantly lowers the substrate's surface energy while the methoxy groups form covalent siloxane bonds, creating a dense, water-repellent layer. This gives long-lasting superhydrophobic, self-cleaning performance on concrete, glass and ceramics.
What ventilation is required when formulating with L1831?
Its hydrolysis releases methanol, a toxic and highly flammable by-product, so provide local exhaust ventilation during formulation and application and keep containers hermetically sealed against moisture.
What does L1831 contribute in highly filled polyolefin compounds?
As a surface modifier for fillers such as ATH, MDH and silica, it reduces melt viscosity, improves processability and maintains mechanical strength in highly loaded compounds.
Related Products
L1831 is one step in the building protection formulation chain. One inquiry can cover the other raw materials in your formulation, with samples, technical documents, quotation and shipment handled together.
- Alkyl Silane Actives
- Emulsions & Pastes
- Siliconate Liquids & Powders
- Waterproof Coatings
Looking for a different purity, functional group, or a structure not listed here? Contact our technical team.
Talk to our technical team
Tell us your application, target properties and estimated quantity. We will suggest grades and arrange documents or samples.