Silane Crosslinking Agent Applications
Liquid silicone rubber can be divided into two types based on its product form: single-component and two-component. Single-component types are most commonly condensation-curing, including deacetylation, dealcoholization, deketoxime, deamidation, deamination, and deacetonation types, with the first three being the most common. Two-component types are mainly condensation-curing, but also include addition-curing types. Condensation-curing liquid silicone rubber mainly includes dealcoholization and dehydrogenation types, while addition-curing liquid silicone rubber is mainly based on platinum-catalyzed hydrosilylation.
Silane crosslinking agents are the core component of single-component room-temperature vulcanizing silicone rubber and are the basis for determining the product's crosslinking mechanism and classification. The choice of silane crosslinking agent for single-component room-temperature vulcanizing silicone rubber mainly depends on factors such as industry, market, and national conditions. For example, in China, acetic acid-type silane crosslinking agents dominated in the early stages, but currently, ketoxime-type and alcohol-type silane crosslinking agents are dominant. Acetic acid-type silane crosslinking agents are only partially used in construction; amide-type silane crosslinking agents are used in small quantities in wide-joint construction; and acetone-type silane crosslinking agents are mainly used in electronics and electrical appliances.
Different silane crosslinking agents have different reactivity with water. Under the same catalyst dosage, the reactivity order is: acetone type > amide type > acetic acid type > ketoxime type > alcohol type.
Acyloxy silane crosslinking agents mainly include methyltriacetoxysilane, ethyltriacetoxysilane, propyltriacetoxysilane, and vinyltriacetoxysilane, along with compounded products of these silanes, forming a group of deacetylation-type silane crosslinking agents with acyloxy groups as the active group.
Ketoxime-type silane crosslinking agents mainly include methyltributanone oxime silane, vinyltributanone oxime silane, tetrabutanone oxime silane, and phenyltributanone oxime silane, along with compounded products of these silanes, forming a group of deketoxime-type silane crosslinking agents with ketoxime groups as the active group. Alcohol-type silane crosslinking agents mainly include methyltrimethoxysilane, tetramethoxysilane, and tetraethoxysilane.
