A simple overview of casting

Casting is a method of plastic processing. Early casting involves injecting liquid monomers or prepolymers (see polymers) into molds under normal pressure, polymerizing and solidifying to form products with the same shape as the mold cavity. At the beginning of the 20th century, phenolic resin was first formed by casting.

In the mid-1930s, polymethyl methacrylate (PMMA) was cast from Methyl methacrylate prepolymer (see polymethyl methacrylate). During the World War II, unsaturated polyester casting products were developed, followed by epoxy resin casting products. In the 1960s, nylon monomer casting (see polyamide) appeared. With the development of molding technology, the traditional concept of casting has changed, and polymer solutions, dispersions (referring to polyvinyl chloride paste), and melts can also be used for casting molding. Using an extruder to extrude a molten flat film and casting it on a cooling drum to shape it, a polypropylene film is produced, known as the extrusion casting method.