Physical Properties

The molding shrinkage rate of phenolic molding plastics depends on various factors, such as the composition of the resin, the type of filler, moisture content, and molding conditions. The linear expansion coefficient of phenolic resin molding plastics is greatly related to the type of filler; as the amount of inorganic fillers like glass fibers in the plastic increases, the linear expansion coefficient decreases, whereas plastics containing synthetic fibers have a higher linear expansion coefficient.

2. Mechanical Properties

Phenolic molding compounds exhibit varying temperature dependence in their room temperature creep resistance, with compounds containing inorganic fillers like mica and asbestos generally demonstrating better creep resistance than those with organic fillers. Generally, molding compounds filled with glass fibers offer improved tensile and bending strengths, with minimal temperature impact. However, certain fillers like wood powder are prone to moisture absorption, which can lead to a decrease in bending strength and modulus.

Electrical Properties

Phenolic resin plastics possess excellent electrical properties, with high insulation performance at room temperature, such as high volume resistance, surface resistance, and breakdown voltage. They can be used as insulating materials; however, their dielectric constant and dielectric loss tangent are relatively large, making them suitable only for power frequency insulation materials.

Corrosion resistance

Phenolic resin without fillers is almost immune to attack by inorganic acids, insoluble in most hydrocarbons and chlorides, and also not soluble in ketones and alcohols. However, it is not resistant to corrosive agents like concentrated sulfuric acid, nitric acid, and hot chromic acid.