Application of silane crosslinkers
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Liquid silicone rubber can be divided into two types according to the form of the product: one-component and two-component. The most common single-component type is the condensation type, including deacetic acid type, dealcoholization type, deketoximate type, deamidation type, deamine type, and deacetone type, among which the first three are the most common. The two-component type is mainly condensation type, and there are also addition types. The condensation type liquid silicone rubber mainly includes dealcoholization type and dehydrogenation type, and the addition type liquid silicone rubber is mainly platinum-catalyzed silane hydrogen addition. Silane crosslinker is the core component of single-component room temperature vulcanized silicone rubber and is the basis for determining the crosslinking mechanism and classification naming of the product. Which crosslinker is used for single-component room temperature vulcanized silicone rubber depends mainly on factors such as industry, market, and national conditions. For example, acetic acid silane crosslinkers dominated in China in the early days, while ketoximate and alcohol silane crosslinkers currently dominate. Acetic acid silane crosslinker products are only partially used in construction; amide silane crosslinker products are used in small quantities in wide-joint buildings; acetone silane crosslinker products are mainly used in electronic appliances. Different silane crosslinkers have different reactivity in reaction with water. Under the same catalyst dosage conditions, acetone type>amide type>acetic acid type>ketoxime type>alcohol type. Acyloxysilane crosslinkers are mainly methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, and vinyltriacetoxysilane. Adding the compound products of the above silane crosslinkers, a group of deacetylating silane crosslinkers with acyloxy groups as active groups is formed. Ketoximine silane crosslinkers are mainly methyltributylacetoximine silane, vinyltributylacetoximine silane, tetrabutylketoxime silane, and phenyltributylacetoximine silane. Adding the compound products of the above silane crosslinkers, a group of deketoxime silane crosslinkers with ketoxime groups as active groups is formed. Alcohol silane crosslinkers are mainly methyltrimethoxysilane, tetramethoxysilane, and tetraethoxysilane.