What is silicone sealant/glue?

Silicone glue is a kind of silicone rubber that can undergo cross-linking and curing reaction at room temperature. It is a paste before the cross-linking and curing reaction; once the cross-linking and curing reaction occurs, it will form a three-dimensional network structure and become an elastomer-like solid. The cured silicone glue has excellent weather resistance, aging resistance, UV resistance, ozone resistance, high and low temperature resistance, vibration resistance, moisture resistance, and waterproof properties; therefore, it has a wide range of uses. In the 1990s, it was often used for glass bonding and sealing, so it is commonly known as “glass glue”. Silicone glue is generally based on 107 glue (hydroxyl-terminated polydimethylsiloxane) as a polymer, plasticizer, filler, cross-linking agent, coupling agent, catalyst and other materials. Among them, the commonly used plasticizers are: silicone oil, white oil, etc.; the commonly used fillers are: nano-active calcium carbonate, heavy calcium carbonate, ultrafine calcium carbonate, gas-phase silica, etc. According to the product packaging and storage type, it is divided into: single component and two (multi) components. The curing process of single-component silicone glue is: when the glue contacts the water vapor in the air, a cross-linking and curing reaction will occur to form an elastomer.
Two (or more) components refer to silicone rubber divided into two (or more) components, A and B. Any one component alone cannot form a cure, but after the two (or more) components are mixed, they will undergo a cross-linking and curing reaction to form an elastomer. Single-component silicone rubber can be roughly divided into deacidification type, dealcoholization type, deketoxime type, deacetone type, deamide type, dehydroxylamine type, etc. according to the cross-linking agent used (or small molecules produced during the curing process). Among them, the deacidification type, dealcoholization type, and deketoxime type are the main types on the market. The deacidification type uses methyltriacetoxysilane (or ethyltriacetoxysilane, propyltriacetoxysilane, etc.) as a cross-linking agent, and its curing process produces acetic acid, commonly known as “acid glue”. Its advantages are: good strength and transparency, and fast curing speed. Disadvantages are: irritating acetic acid odor and corrosion to metals.
The dealcohol type uses methyltrimethoxysilane (or vinyltrimethoxysilane, etc.) as a crosslinking agent, and the curing process produces methanol, commonly known as “alcohol type glue”. Its advantages are: environmental protection and non-corrosive. Disadvantages are: slow curing speed and slightly poor storage shelf life.
The dealcohol oxime type uses methyltributylanoxime silane (or vinyltributylanoxime silane, etc.) as a crosslinking agent, and the curing process produces butanone oxime, commonly known as “oxime type glue”. Its advantages are: no strong odor and good adhesion to various materials. Disadvantages are: corrosion to copper.