BRB Silanil® 260 is an epoxy silane which contains reactive glycidoxy and triethoxysilyl inorganicgroup. CAS# is specified as 2602-34-8.
BRB Silanil® 260 possesses both organic and inorganic reactivity that allows it to react with or "couple" organic polymers and inorganic surfaces. This dual reactivity should be considered when using BRB Silanil® 260 in specific applications. BRB Silanil® 260 is particularly recommended as:
Glass Fiber Size Process
BRB Silanil® 260 can be applied in inorganic surfaces e.g. glass fibers and fabrics, as a dilute aqueous solution (0.1 to 0.5% silane concentration). Aqueous solutions are prepared by adjusting the pH of the water from 3.5 to 4.5 with about 0.1% acetic acid and then adding the silane and stirring. After adding the silane to the acidified water, it is necessary to stir the mixture for about 15 minutes before it hydrolyses and forms a clear homogeneous solution. Higher concentrations of BRB Silanil® 260 in water may be not stable indefinitely and after standing several days may deposit an oily phase of condensed polysiloxane. Silane solution is recommended to add together with organic resin, water and other additives to form film on glass surface during size process. Solubility and stability should be verified before use in a commercial process.
Mineral filler treatment
In the case of mineral fillers, the mineral can be treated by mixing with the silane solution at very low shear for several minutes. The silane solution can be prepared by the mixture of 1:8:1 by volume of BRB Silanil® 260 : isopropanol : water and a few drops of acetic acid can be added to accelerate hydrolysis rate and coupling of silane on filler surface. After applying the silane, the glass or mineral surface should be dried briefly at 104°C to 121°C (220-250°F) to effect condensation of silanol groups at the surface and to remove traces of ethanol from hydrolysis of the ethoxysilane. Optimum application and drying conditions such as time and temperature should be determined for each application prior to use in a commercial process.
For use as a primer, 49.5 parts of BRB Silanil® 260 and 0.5 parts of an organic amine such as benzyldimethylamine (mixture A) are diluted with about 950 parts methanol, isopropanol or ether glycol. Alternatively, a prehydrolyzed primer may be prepared by adding 5 parts water and 1,000 parts of the above primer solution. In both cases, the primer solution is applied to a solid surface such as glass or metal and a polymer is heat pressed or cured on the surface.
Adhesion Promoter in Coatings and Adhesives
BRB Silanil® 260 can be added directly to a resin system without other additives or pigments at 0.5 to 2.0 pph to promote unprimed adhesion. For waterborne resin, pH of resin is preferred near to neutral or pH of resin should be < 8.5 before adding silane. Induction time is needed after adding silane into resin which pH may be increased during induction time comparing to resin without silane. Typical induction time is 5-48 hours. Proper induction time is able to study by pH evolution curve/time until flat point which is pH evolution became stable. High shear and agitation is also able to accelerate the induction time. Additives, Fillers and Pigments are recommended to add after induction time. If pH adjustment is required for final coatings, it is recommended to adjust pH after the induction time as well.