The unique chemical structure of phenolic resin makes phenolic resin have many different excellent characteristics, such as wear resistance, oil resistance, corrosion resistance, etc., and at the same time, it has good adhesion, flame retardant, insulation and other characteristics.
1. Heat resistance
Phenolic resin has excellent thermal stability after curing because of its aromatic ring structure and high cross-linking density. The structural integrity and dimensional stability are basically stable below 200 ℃, and can be used for a long time under the condition of no more than 180 ℃. Therefore, phenolic resin is used in some high temperature fields, such as refractories, friction materials, binders and foundry industry.
Phenolic resin has excellent adhesion. At the same time, the solid powder made before curing has the processability of fusibility and fluidity. It has good wettability on the surface of filler and reinforcer. When the phenolic resin binder is transformed into cross-linked network structure and cured, it can ensure the stability and durability of the bonding interface. Therefore, a variety of composite materials with phenolic resin as binder and various fillers or reinforcing materials have excellent physical, chemical and service properties.
3. Flame retardancy
Phenolic resin has a high carbon residue rate. Under the condition of 1000 ℃ inert gas, phenolic resin will absorb a lot of heat and form a high strength carbonized layer with heat insulation function. Therefore, it can meet the requirements of flame retardancy without adding flame retardant, which is also an important reason why it can be used in the field of refractories. At the same time, it has the characteristics of low smoke emission and low smoke toxicity. Adding flame retardant can further enhance the flame retardancy.
4. Corrosion resistance
The structure of crosslinked phenolic resin is compact and stable, so it has good corrosion resistance and can resist the decomposition of most chemical substances. For example, strong acid, gasoline, petroleum, alcohol, glycol and various hydrocarbons, especially acid resistance.
5. Electrical insulation
Phenolic resin has good insulation and low conductivity. Thermosetting phenolic resin is widely used in the field of electronic devices
However, it should be noted that phenolic resin also has some defects such as high shrinkage, brittleness and moisture absorption. In order to overcome these shortcomings, domestic and foreign enterprises mainly focus on the modification of phenolic resin and the research of composite materials.
In general, phenolic resin has excellent physical and chemical properties, sufficient supply of raw materials, simple synthesis process and low price, so it is widely used in various fields of industry. With the development of technology, phenolic resin has been continuously improved, mechanical strength, heat resistance and flame retardant properties have been improved, application fields have been expanded, and the demand has maintained a stable growth trend. At present, it is widely used in molding materials, friction materials, abrasive materials, refractories, filter materials, thermal insulation materials and electronic materials.