Definition of Thermosetting Plastics
Thermosetting plastics are a class of polymers that form an irreversible three-dimensional cross-linked molecular structure through heating or chemical reactions (such as cross-linking). Once cured and shaped, thermosetting plastics cannot be softened or melted again, making them non-reprocessable and non-recyclable.
They are typically processed using compression molding, transfer molding, or injection molding techniques.
Common thermosetting plastics include Epoxy Resin, Phenolic Resin, Unsaturated Polyester Resin (UPR), Polyurethane (PU), and Bulk Molding Compound (BMC).

Advantages of Thermosetting Plastics
1. Excellent Heat Resistance
The cross-linked structure provides outstanding high-temperature performance, making the material resistant to softening or deformation and suitable for demanding thermal environments.

2. High Mechanical Strength
The rigid network molecular structure offers superior hardness, stiffness, and compressive strength — ideal for structural components.

3. Superior Chemical Resistance
Highly resistant to acids, alkalis, and solvents, making them ideal for chemical industry applications and corrosive environments.

4. Dimensional Stability
Once cured, thermosetting plastics maintain their shape with a low thermal expansion coefficient and strong resistance to deformation — suitable for precision parts.

5. Excellent Electrical Insulation
Widely used in electrical and electronic applications such as circuit boards and insulating components due to their non-conductive and high-voltage-resistant properties.

6. Long-Term Durability
Exceptional aging resistance makes them ideal for long-lasting products such as automotive parts, construction materials, and aerospace components.

Unique Advantages of BMC (Bulk Molding Compound)
BMC, a type of thermosetting plastic, contains high filler content (including glass fibers and other reinforcing materials) while maintaining good flowability. It is particularly well-suited for compression molding of complex-shaped parts, offering excellent mechanical strength, electrical insulation, and corrosion resistance.
BMC is widely used in electrical enclosures, automotive components, and industrial parts.