The vulcanization of one-component room temperature vulcanized silicone rubber is initiated by moisture in the air. The commonly used cross-linking agent is methyltriacetoxysilane, whose Si-OC bond is easily hydrolyzed, and the acetoxy group combines with the hydrogen group in water to form acetic acid, and the hydroxyl group in water is transferred to the original acetoxy group. Positionally, it becomes trishydroxymethylsilane. Trishydroxymethylsilane is extremely unstable and easily condenses with a linear organosilicon having a terminal hydroxyl group to form a crosslinked structure. Usually, the silicone raw rubber containing silanol end groups and fillers, catalysts, cross-linking agents and other compounding agents are put into a sealed hose, which is extruded from the container during use and vulcanized by means of moisture in the air. Elastomers, while releasing low molecular weight. The crosslinking agent may be a silane containing an alkoxy group, a thiol group, an amine group, an amide group or a ketone group in addition to the methyltriacetoxysilane. When alcohol is exchanged with an alkoxy group, it is called a dealcoholized one-component room temperature vulcanized silicone rubber. When it is crosslinked with a sulfhydryl group, it is called a deuterium type room temperature vulcanized silicone rubber. Therefore, with the cross-linking Different components, single-component room temperature vulcanized silicone rubber can be many types such as deacidification type, depurination type, dealcoholization type, deamination type, deamidation type and deketone type, but the deacidification type is currently the most widely used. One.




The vulcanization time of the one-component room temperature vulcanized silicone rubber depends on the vulcanization system, temperature, humidity, and thickness of the silicone rubber layer. Increasing the temperature and humidity of the environment can accelerate the vulcanization process. Under typical environmental conditions, after 15 to 30 minutes, the surface of the silicone rubber may be non-tacky, and a layer of 0.3 cm thick may be cured in one day. The depth and strength of curing will gradually increase in about three weeks.




The one-component room temperature vulcanized silicone rubber has excellent electrical properties and chemical inertness, as well as heat resistance, natural aging resistance, flame resistance, moisture resistance, and gas permeability. They maintain flexibility for a long period of time in the range of -60 to 200 °C. It does not absorb heat when it is cured, does not release heat, has a small shrinkage after curing, and has good adhesion to materials. Therefore, it is mainly used as an adhesive and sealant, and other applications include in-situ molded gaskets, protective coatings and caulking materials. Many single-component silicone rubber adhesive formulations exhibit automatic bonding properties on a variety of materials such as most metals, glass, ceramics and coagulations, such as bare aluminum, with shear strengths up to 200 lbs/ft. 2, tear strength up to 20 pounds · 呎 / 吋 2 (0.35 joules / cm 2). When the bonding is difficult, the primer may be applied to the substrate to improve the bonding strength. The primer may be a reactive silane monomer or resin, and when they are cured on the substrate, a modified layer is formed. On the surface of silicone bonding.




Although the one-component room temperature vulcanized silicone rubber is convenient to use, since the vulcanization is based on the moisture in the lazy atmosphere, the thickness of the vulcanized rubber is limited, and it can only be used in applications requiring a thickness of 6 mm or less.




The vulcanization reaction of the one-component room temperature vulcanized silicone rubber is carried out gradually from the surface to the depth, and the thicker the rubber layer, the slower the curing. When the deep part is also to be solidified quickly, the layered watering stepwise vulcanization method can be used, and some rubber can be added each time, and then the vulcanization is added, which can reduce the total vulcanization time. The addition of magnesium oxide accelerates the vulcanization of the deep glue.




Two-component room temperature vulcanized silicone rubber two-component room temperature vulcanized silicone rubber can be further divided into condensation type and addition molding.
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