Silane N-Octyltriethoxysilane (CAS 2943-75-1)

Description

Manta L320 is high purity, undiluted N-octyltriethoxy-silane. When diluted with an appropriate solvent, it can be used in the formulation of water repellent products. Upon proper application, the formulated product will penetrate and provide water repellency by chemically reacting with the cementitious substrate. Treated substrates are hydro-phobic and retain their original appearance.

L320 can also be used to improve the compatibility of mineral fillers or pigments in polyolefins or to ease their dispersion in nonpolar matrices.

L320 is a small molecule to allow for deep penetration into the cementitious surface. This material reacts with moisture in the air and in the substrate in the presence of an alkaline or acidic environment to produce hydroxy groups. These hydroxy groups will bond with the substrate and itself to produce a hydrophobic treatment that inhibits water absorption into the substrate. An alkaline environment, such as new concrete, will catalyze the reaction and speed the formation of the hydrophobic surface.

Typical Physical Properties

Applications

1) Octyltriethoxysilane can be used as a Surface Modifier to generate hydrophobicity (e.g. on concrete, glass, inorganic pigment, or mineral fillers)

2) When diluted with an appropriate solvent, it can be used in the formulation of water repellent products. Upon proper application, the formulated product will penetrate and provide water repellency by chemically reacting with the cementitious substrate. Treated substrates are hydrophobic and retain their original appearance.

### Reaction Characteristics:

OCTEO silane actively interacts with moisture present in materials and air. In the presence of specific acids or bases as catalysts, its alkoxy groups undergo hydrolysis, forming reactive silanol groups and releasing ethanol as a byproduct. These silanol groups condense with hydroxyl groups on surfaces of various inorganic materials (such as siliceous stone, concrete, bricks, tiles, pigments, and fillers), establishing chemical bonds. The octyl groups orient toward and within the material's surface, creating a water-repellent layer that adds a degree of thickness.

OCTEO is a small molecule silane that easily penetrates materials like concrete and bricks. It reacts with atmospheric or substrate moisture in acidic or basic environments, generating hydroxyl groups. These groups condense with silanol on the substrate or the OCTEO itself, forming a stable, three-dimensional hydrophobic barrier that blocks moisture infiltration. Alkaline environments, like new concrete, accelerate this reaction, facilitating faster formation of the hydrophobic layer.

When preparing an aqueous solution of OCTEO, an organic acid catalyst (e.g., formic or acetic acid) is used, adjusting the pH to around 3.5–4.5 before adding and stirring the silane for at least 30 minutes until fully dissolved. Concentration should remain low, ideally under 2%, and solutions should be used within 24 hours, as fogging signals partial polymerization to ineffective silane polymers.

For mineral fillers, mixing minerals with silane under high-speed shear is sufficient, with no added solvents needed. After treatment, substrates should be briefly dried at 104–121°C to ensure polycondensation and remove ethanol from hydrolysis. OCTEO is suited for a range of inorganic materials, including glass, quartz, and certain metals, but is less effective on fillers without surface hydroxyl groups, like calcium carbonate or graphite.

### Solvent Selection:

OCTEO silane can be diluted in solvents like alcohol, carbon tetrachloride, or solvent oil, typically at concentrations of 20% or 40%. Drying speed depends on the volatility of the solvent, solution concentration, and temperature. If the treated surface blackens, switching solvents may help. Generally, a 40% solution can penetrate concrete to a depth of 3–5 mm. Ensure proper ventilation and fire safety when using solvents.

### Usage Instructions:

Application of OCTEO silane solution can be done with spray guns, rollers, or brushes. With brushes or rollers, apply until the surface stays wet for several minutes. For spraying, ensure thorough permeation. Solvent-resistant hoses and gaskets should be used with spray equipment. Conduct a test application to confirm compatibility and determine coverage for waterproofing. Surfaces should be clean and dry to optimize silane penetration.

OCTEO solutions can be applied to damp surfaces, but a dry surface maximizes penetration and effectiveness.

### Important Notes:

For optimal performance, apply OCTEO to new, highly alkaline concrete (less than one year old). Its effectiveness diminishes on older or neutral surfaces and is unsuitable for areas subject to fluid pressure. Avoid use in temperatures below 0°C or windy conditions to prevent rapid solvent evaporation. Protect plants, animals, and other sensitive materials from direct exposure to the treatment.

### Typical Uses:

1. **Waterproofing and Protection in Construction**: Used on concrete and stone, OCTEO forms a protective, dense layer that prevents water and environmental factors from damaging the substrate, prolonging building life.

2. **Surface Treatment for Inorganic Fillers**: It improves filler dispersibility and compatibility in plastics, rubbers, and resins, suitable for various inorganic powders.

3. **Pigment Dispersant**: Treated pigments and fillers gain hydrophobic properties and disperse well in non-polar resins or solvents, enhancing performance.