The difference between silane coupling agent and silane crosslinking agent

There are many varieties of silicones, among which silane coupling agents and crosslinking agents are relatively similar. Generally, those who are new to silicone are difficult to understand. What is the connection and difference between the two?

Silane Coupling Agent

It is a kind of organosilicon compound containing two different chemical properties in the molecule at the same time, which is used to improve the actual bonding strength between polymers and inorganic substances. This can refer either to an increase in true adhesion or an improvement in wettability, rheology, and other handling properties. The coupling agent may also modify the interfacial region to enhance the boundary layer between the organic and inorganic phases.

Therefore, silane coupling agents are widely used in adhesives, coatings and inks, rubber, casting, glass fiber, cables, textiles, plastics, fillers, surface treatment and other industries.

Common silane coupling agents are:

Sulfur-containing silanes: bis-[3-(triethoxysilicon)-propyl]-tetrasulfide, bis-[3-(triethoxysilicon)-propyl]-disulfide

Aminosilane: γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane

Vinylsilane: vinyltriethoxysilane, vinyltrimethoxysilane

Epoxysilane: 3-glycidyloxypropyltrimethoxysilane

Methacryloxysilane: γ-Methacryloxypropyltrimethoxysilane, γ-Methacryloxypropyltriisopropoxysilane

Silane Crosslinker

It refers to a silane containing two or more silicon functional groups, which can act as a bridge between linear molecules, so that multiple linear molecules or slightly branched macromolecules and polymers can be bonded and cross-linked to form a three-dimensional network. It promotes or mediates the formation of covalent bonds or ionic bonds between polymer molecular chains.

The cross-linking agent is the core part of the one-component room temperature vulcanized silicone rubber, which is the basis for determining the cross-linking mechanism and classification and naming of the product.

According to the different condensation reaction products, one-component RTV silicone rubber can be divided into different types such as deacidification type, deketoxime type, dealcoholization type, deamination type, deacetone type, etc. Among them, the first 3 A general-purpose product for mass production.

Taking methyl triacetoxysilane crosslinking agent as an example, because the condensation reaction product is acetic acid, it is called deacetic acid type RTV silicone rubber.

Generally speaking, cross-linking agents are different from silane coupling agents, but there are exceptions. For example, α series silane coupling agents represented by aniline methyl triethoxy silane are used in one-component dealcoholized room temperature vulcanization silicon Widely used in rubber.

Common silane crosslinkers are:

Dealcoholized Silane: Alkyltriethoxy, Methyltrimethoxy

Deacidified silane: triacetoxy, propyl triacetoxy silane

Deketoxime silane: vinyl tributyl ketoximo silane, methyl tributyl ketoximo silane