Silquest A-1170 Silane

Silquest A-1170 silane, a secondary aminofunctional silane, is useful in a broad range of applications to promote adhesion between inorganic substrates and organic polymers. It can function as a crosslinker for urethane, epoxy and other polymers that can be endcapped or otherwise modified with a secondary amine. Such modification provides a moisture-cure mechanism for these polymers. In urethane systems with an isocyanate moisture-cure mechanism, the product can reduce the amount of isocyanate required to yield a given level of crosslinking. It also will improve adhesion to plastic in many resin systems.

The silane is recommended for evaluation in adhesive, sealants and coatings to achieve weather- and moisture-resistant bonds to substrates with difficult adhesion properties such as glass, metal, concrete and plastic. Durable water-resistant bonds are generally achieved when the silyl portion of this aminosilane is condensed with an inorganic surface and is covalently bonded with the resin matrix of the paint, sealant or adhesive.

Because of its unique structure, the product is particularly suitable for use in primerless, one-part, moisture-cured polyurethane systems. The secondary amino group reacts quantitatively and controllably with free isocyanate groups. This reaction with isocyanate-terminated prepolymers is feasible over a wide molar ratio from >0 to 100% aminosilane, based on terminal isocyanate. The moisture cure of A-1170 silane is a combination of isocyanate/water reactions and silane crosslinking reactions. The resulting bis-silyl endcapped prepolymer provides enhanced crosslinking for a given level of isocyanate, thus allowing the quantity of isocyanate to be reduced. Biuret-forming side reactions common with primary amino groups are minimized. This leads to improved product consistency and improved shelf life.

The bis-alkoxysilane structure of the product results in the addition of two silyl groups to each isocyanate group, yielding more durable wet adhesion and more efficient bonding per mole of added silane. The methoxy groups provide rapid reaction with moisture and rapid attainment of substrate bonding.

Having both alkoxysilane and free isocyanate groups on the same polyurethane molecule, the silane facilitates the preparation of partially endcapped isocyanate prepolymers. This feature leads to improved formulating flexibility for tailoring mechanical properties and for wet adhesion.

This versatile silane can be used in several ways. It can be added directly to the urethane prepolymer or during system formulation, or it can be used independently as a primer. When used in neutral-cure RTV silicone formulations, it can give exceptional adhesion to a variety of plastics.

Crompton Corp., One American Ln., Greenwich, CT 06831-2559. Tel: 800-295-2392. Fax: 607-754-7517.