Nanjing SiSiB Silicones Co., Ltd.
Nanjing SiSiB Silicones Co., Ltd.
SiSiB® PC5911
SiSiB® PC5911


SiSiB® PC5911 is high purity, undiluted iso-octyltrimethoxysilane. 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.

SiSiB® PC5911 silane crosslinking agent 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 hydroxyl 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.

SiSiB® PC5911 is the equivalent of Dow's Z-6672, Wacker's IO-TRIMETHOXY.

SiSiB® PC5911

Technical Data







Molecular Weight


Boiling Point

182°C [760mmHg]

Flash Point


Color and Appearance

Colorless clear liquid

Density 25/25°C


Refractive Index

1.4176 [20°C]




  • SiSiB® PC5911 should be diluted in solvents such as alcohols, chlorinated solvents, aliphatic solvents, and low molecular weight cyclic polydimethylsiloxane, such as SiSiB® CF1040 Fluid before use. Typical dilution levels are 40% and 20% SiSiB® PC5911 in a solvent.

  • Methods of application include airless sprayer, roller and brush. When a brush or roller is used, repeated applications should be made until the surface remains moist for a few minutes. If an airless sprayer is used, application should continue until the substrate is thoroughly saturated. Sprayers should be fitted with solvent resistant hoses and gaskets. A test application is necessary on each surface to be treated to ensure compatibility and the desired water repellent result. Surfaces should be free of standing water, surface dirt, dust, oils, and other contaminants. The formulated SiSiB® PC5911 may be applied to damp surfaces although dry surfaces are preferred to achieve maximum penetration into the substrate.

  • SiSiB® PC5911 alkyl alkoxy silane can be used as a surface modifier to generate hydrophobicity and to increase compatibility to organic non polar matrices.

  • Blends of the solvents can also be used. The evaporation rate of the diluted material can be modified depending on the type and concentration of the solvent. Select the proper solvent for your application, as some silane/solvent blends may darken the surface.

Packing and Storage

  • SiSiB® PC5911 is supplied in 175Kg steel drum.

  • In the unopened original container SiSiB® PC5911 has a shelf life of one year in a dry and cool place.

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SiSiB® PC5911