One-component alkoxy silicone sealant releases alcohol during curing, which is pollution-free and non-corrosive. It can be widely used on sensitive or corrodible substrates such as metals and/or marble. As a green and environmentally friendly adhesive alcohol sealant, it will be the trend of future market applications. At present, alkoxy RTV-1 silicone sealant is mainly based on α, ω-dihydroxyterminated polydimethylsiloxane (OH Polymer) as the base polymer, methyltrimethoxysilane as the crosslinking agent, organic titanium as the catalyst, filler and other additives.
But they have 3 main disadvantages:
The hydroxyl group in OH Polymer easily reacts with the vulcanizing agent (such as organotin, organotitanium), which increases the molecular weight and viscosity of the silicone polymer, which brings trouble to production.
The hydroxyl groups in OH Polymer easily form hydrogen bonds with the hydroxyl groups on the surface of the inorganic filler, making it difficult to disperse the silicone filler, resulting in "structuralization" and poor processing performance.
During storage, OH Polymer reacts with the cross-linking agent and releases methanol. Under the action of the catalyst, the main chain is easily degraded into monoalkoxy-terminated oligosiloxane, which is difficult to cure.
Therefore, SiSiB, a reliable silicone manufacturing company, has developed alkoxy-terminated polydimethylsiloxane as a base polymer, which can avoid the problem of peak viscosity of OH Polymer and titanate complexes, as well as structural problems between OH Polymer and fillers, and effectively improve the shelf life.
SiSiB alkoxy terminated polymer SiSiB® PF1071 and SiSiB® PF1073 are ready-for-processing silicone polymers for producing condensation-curing silicone sealing compounds. They are moisture-curable after adding a suitable catalyst.