What are the Types of Silicone Adhesives

Mar 4, 2022

Properties and types of silicone adhesives
Basic properties of silicone adhesives Silicone adhesives have unique heat and low temperature resistance, good electrical properties and weather resistance, chemical stability, hydrophobic moisture resistance, oxidation resistance, workability, sealability, breathability The electrical properties change very little in a wide temperature range, and the dielectric loss is low. It can be made into high-grade sealing material, mainly used for sealing bonding of window glass and glass curtain wall. At present, there are mainly one-component, two-component, flame-retardant and high-temperature resistant silicone sealants. At present, China consumes about 10,000 tons of silicone sealant every year. According to the application requirements of the product in different occasions, we design and manufacture organosilicon materials with different molecular structures, such as: ① changing the molecular structure of the main chain of polysiloxane; ② changing the organic groups bound to silicon atoms; ③ selecting different types of reactions and curing method; 4. Modified with organic resin; 5. Choose various fillers; 6. Choose various secondary processing technologies;
Types of Silicone Adhesives Over the past 50 years, more than 2,000 kinds of silicone products have been developed abroad, and about 1,000 are commonly used. However, the main types of adhesives used are room temperature curing silicone rubber (RTV) and low temperature curing silicone rubber (LTV). Their uses are roughly classified as follows.
(1) Bonding Bonding and sealing of components.
(2) Coating temperature, dust, ozone and ultraviolet.
(3) Potting Anti-moisture, dust-proof, anti-corona arc discharge, shock absorption, buffering.
Silicone rubber can be divided into one-component and two-component types according to the formation, and can be divided into two types according to the curing reaction: condensation type and addition type.
The curing speed of the condensation type (especially the one-component type) is related to the concentration and temperature of moisture in the air, and only heating cannot accelerate the curing. Among the condensed silicone rubbers, dealcoholization and deacetone types are mainly used for electronic and electrical components. The deoxime type emits condensation reaction products during curing.
When it comes to "adhesive", many people may be confused, and to put it another way, "glue", suddenly realized. Professionally known as adhesives, the range of adhesives is too wide, solid glue sticks, liquid glue, glass glue for home improvement, etc. all belong to the category of adhesives. Adhesives are used in everything from food, clothing, housing and transportation to aerospace. Silicone is one of them.

Silicone? What is Silicone? Organosilicon compounds refer to compounds that contain Si-C bonds and at least one organic group is directly connected to a silicon atom. It is also customary to use those compounds that connect organic groups to silicon atoms through oxygen, sulfur, nitrogen, etc. Also used as organosilicon compounds. Among them, the polysiloxane composed of silicon-oxygen bond (-Si-O-Si-) as the skeleton is the most numerous, the most deeply studied and the most widely used type of organosilicon compounds, accounting for more than 90% of the total dosage. .

What are the types of silicone adhesives? (1) Silicone rubber: high temperature vulcanized silicone rubber HTV, room temperature vulcanized silicone rubber RTV (2) silicone resin (3) silicone oil
Compared with other types of polymer materials, what are the excellent properties of silicone?

The basic structural unit of silicone products is composed of silicon-oxygen chains, and the side chains are connected to various other organic groups through silicon atoms. Therefore, the structure of silicone products contains both "organic groups" and "inorganic structures". This special composition and molecular structure make it combine the characteristics of organic substances with the functions of inorganic substances. Compared with other polymer materials, the most outstanding properties of silicone products are:

1. Temperature resistance
Silicone products are based on silicon-oxygen (Si-O) bond as the main chain structure, the bond energy of C-C bond is 82.6 kcal/mol, and the bond energy of Si-O bond is 121 kcal in silicone /molecule, so the thermal stability of silicone products is high, and the chemical bonds of the molecules are not broken or decomposed under high temperature (or radiation exposure). Silicone is not only resistant to high temperatures, but also low temperatures, and can be used in a wide temperature range. Whether it is chemical properties or physical and mechanical properties, the change with temperature is very small.

2. Weather resistance
The main chain of silicone products is -Si-O-, and there is no double bond, so it is not easy to be decomposed by ultraviolet light and ozone. Silicone has better thermal stability, radiation resistance and weather resistance than other polymer materials. The service life of silicone in natural environment can reach several decades.

3. Electrical insulation properties
Silicone products have good electrical insulation properties, and their dielectric loss, withstand voltage, arc resistance, corona resistance, volume resistivity and surface resistivity are among the best in insulating materials, and their electrical properties are affected by temperature and frequency. impact is small. Therefore, they are a stable electrical insulating material and are widely used in the electronics and electrical industries. In addition to excellent heat resistance, silicone also has excellent water repellency, which enables electrical equipment to be used in wet conditions with high reliability.

4. physiological inertia
Polysiloxanes are among the most inactive compounds known. They are very resistant to biological aging, have no rejection reaction with animals, and have good anticoagulant properties.

5. Low surface tension and low surface energy
The main chain of silicone is very flexible, and its intermolecular force is much weaker than that of hydrocarbons. Therefore, it has lower viscosity, weaker surface tension, lower surface energy, and stronger film-forming ability than hydrocarbons of the same molecular weight. This low surface tension and low surface energy are the main reasons for its many applications: hydrophobicity, defoaming, foam stabilization, anti-sticking, lubrication, glazing and other excellent properties.

It is these excellent properties of silicone that silicone products are widely used in military/aerospace/construction/electrical/electronics/automotive/leather/textile/chemical/medicine and medical industries.