The definition of plastic in the broad sense refers to a material with plastic behavior. The so-called plasticity refers to the state when the external force acts to deform and the external force is retained after the external force is removed. The elastic modulus of plastic is between rubber and fiber, and the force can undergo a certain deformation. Soft plastic is close to rubber and hard plastic is close to fiber. The narrow definition of plastic refers to the use of resin (or direct polymerization of monomer during processing) as the main component, supplemented by additives such as plasticizers, fillers, lubricants, and colorants, and can be flow-formed during processing. s material. Plastics are synthetic polymer compounds that can be freely changed in shape. Plastics are materials that are made by polymerizing monomer materials using a synthesis or condensation reaction.