'

Product Background: R-Guard silyl-terminated polymer formulations & Targeted Interior Air Seal

Certain R-Guard products feature a distinct polymer backbone known as Silyl-Terminated Polymer or STP, which is characterized by terminal silanol groups that significantly enhance moisture resistance and flexibility. Its unique structure facilitates exceptional adhesion properties, making it particularly well-suited for applications requiring high durability and resilience. The integration of silane functionalities further improves the material’s compatibility with a variety of substrates, ensuring robust bonding performance even in challenging environments. This polymer demonstrates outstanding thermal stability and is engineered to endure extreme conditions while maintaining its performance integrity. Its low viscosity enables seamless processing and incorporation into diverse formulations, establishing it as a versatile option across multiple applications. This chemistry is different than and not to be confused with Silanol-terminated polyurethanes, Silanol-terminated polyesters, Silicone Sealants, Polydimethylsiloxane (PDMS), Silane-modified epoxy resins, Silane-modified acrylics, Polyvinyl Siloxanes, Polyetheramines, Thermoplastic Polyurethanes (TPUs), or Polyolefins with Silane Functionalization.

R-Guard StuccoPrime® is a flexible primer interface (liquid lath) that allows stucco or other materials with sufficient silica content to be direct-applied to CMU, masonry and concrete surfaces which have been coated with R-Guard Cat 5™ or R-Guard FastFlash®. Cementitious stucco, mortars and plasters bond tenaciously to StuccoPrime® while preserving the integrity of the underlying waterproofing membrane. The stucco scratch coat is applied to wet StuccoPrime, and the two cure together forming a strong chemical and mechanical bond. StuccoPrime® is not water reduced and will not emulsify when exposed to water. This single-component, 100% solids, Silyl-Terminated Polymer (STP) is designed for brush, roller or trowel application.

Silyl-terminated polymers (STP) are polymers that contains silane groups, and when it interacts with the silica-based sand in the stucco, the covalent bonds are formed between hydroxyl groups on the sand's surface and methoxy silyl groups in STP polymer. These covalent bonds establish strong bonds with both the STP and the silica. The methoxy silyl groups might also form hydrogen bonds together with the hydroxy groups on the sand’s surface, which also helps the adhesion between STP and stucco, if the methoxy silyl groups are not fully reacted with the moisture or hydroxy groups. This synergy enhances the overall bond strength and durability of the stucco system, making the interaction between STP and silica sand a key factor in creating a robust and long-lasting adhesive bond. Silyl in silyl-terminated polymers (STP), sil in the silane component of STP, and sil in silica, of which sand is made, are present because all materials share a common feature, which is the presence of silicon and oxygen atoms, a fundamental construction that contributes to their chemical structures and bonding characteristics. The Safety Data Sheet provides the following information under "Composition / Information on Ingredients."

r-guard-1

Another STP product is as yet un-named, and it contains hollow, lightweight non-compressible microspheres. It has been shipped in bulk containers such as 5-gallon pails, and it can be shipped in smaller containers, in cartridges and in sausage units. It can be applied with bulk caulk guns or sprayed out of large or small airless spray units normally used for paints. With sprayers, the technique is to place the tip guards in contact with exterior 4-foot wide sheathing sheets or boards so that the narrow bead of material that exits the spray nozzle directly contacts, fills and covers the seams between sheathing boards. There, it cures without tooling to form an airtight and water-resistive barrier over which the field-of-the-wall air and water-resistive barrier is fluid-applied or mechanically installed. Like the other STP products, this one can be applied to damp substrates and rained on immediately.

PROSOCO has a product called Targeted Interior Air Seal that is similar to the seam sealer described in the previous paragraph, except that it is designed for use on interior surfaces that are dry and not to be rained on. It is based on acrylic chemistry. It could also be used on exterior substrates should PROSOCO determine to market it for that purpose.

The STP version may also be used for interior applications. Due to its higher cost, it is likely to be used for such projects only when wet substrates exist as a result of water intrusion or plumbing problems.