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GRP roof tiles are a commonly used building material with the advantages of lightweight, corrosion resistance, and good weather resistance. They are widely used in the roofs and walls of buildings. Ho...
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The SMC insulator is a high-strength, high-insulation, lightweight insulating material. It is primarily composed of quartz, glass fiber, and other materials combined with resin. It finds extensive app...
Ⅰ. Introduction of molding compound
Molding compound is a type of plastic. Compared with common thermoplastics, molding compound has higher geometric dimensional stability, more resistance to extreme heat and humidity and complex environments, chemical resistance, and high mechanical strength.
Ⅱ. The function of molding compound
1. Physical function
The molding shortening rate of molding compound depends on many factors, such as resin composition, filler species, moisture content and molding conditions. The coefficient of linear expansion of phenolic resin molding compound is closely related to the variety of fillers. With the increase of inorganic fillers such as glass fibers in the plastic, the coefficient of linear expansion decreases, while the coefficient of linear expansion of plastics containing synthetic fibers is larger.
2. Mechanical function
The creep resistance of the molding compound at room temperature varies with the filler and has a different dependence on temperature. The molding compound containing inorganic fillers such as mica and asbestos has better creep resistance than the molding compound containing organic fillers. Generally speaking, the tensile strength and flexural strength of the glass fiber as filler molding compound is better, and it is less affected by temperature, and some fillers such as wood flour are easy to absorb moisture. This will cause a decrease in bending strength and bending modulus.
3. Electrical function
Molding compound has outstanding electrical functions. It has higher insulation functions at room temperature, such as higher volume resistance, surface resistance and breakdown voltage. It can be used as an insulating material, but its dielectric constant and dielectric loss tangent are large and can only be used as a power frequency insulating material.
4. Corrosion resistance
Filler-free molding compounds are hardly corroded by inorganic acids, are insoluble in most hydrocarbons and chlorides, and are insoluble in ketones and alcohols. But it is not resistant to corrosion by concentrated sulfuric acid, nitric acid, and high temperature chromic acid.
