Modification technology includes physical methods such as blending, filling and reinforcement and chemical methods such as copolymerization and crosslinking. Physical methods are important modification methods at present. Appropriate modifiers and fillers need to be selected for blending and filling to achieve specific modification purposes.

  (1) Modifier

  Modifiers or additives can be divided into processing additives and functional additives.

  Processing aids are used to improve the processing rheology and molding properties of plastics, mainly including: lubricant - improving the fluidity of substrate; Heat stabilizer and antioxidant - improve the thermal stability of the substrate; Dispersant - improve the dispersibility of the substrate; Compatibilizer and coupling agent - improve the compatibility of substrate; Bridging agent and tackifier - improve the melting strength of the substrate.

  Functional additives are mainly used to improve the physical and chemical properties of substrates, including fillers and nucleating agents - to improve the rigidity and strength of substrates; Impact modifier - improve the impact of substrate; Flame retardant - improve the flame retardancy of the base material. When the modified material is attacked by fire source, it can effectively prevent, delay or terminate the spread of flame; Stabilizer - improve the weather resistance of the substrate; Conductive coating filler and antistatic agent - improve the conductivity of the substrate. Antistatic agent can reduce the electrostatic accumulation of plastics in the process of processing and use and reduce the surface resistivity of materials; Plasticizer - improve the soft hardness of the substrate; Foaming agent - change the density of the substrate; Pigment - change the transparency and color of the substrate.

  (2) Modification method

  The modification methods of resin can be divided into physical methods and chemical methods, including filling, blending, reinforcement, copolymerization, crosslinking and so on. At present, the mainstream modification technology is the physical modification technology based on filling, blending and reinforcement.

  Filling is the blending of fillers such as minerals and modifiers with plastics to improve the shrinkage, hardness and strength of plastics; Blending is to add one or more other resins, modifiers or minerals to improve the original properties; Reinforcement is the blending of glass fiber and plastic to enhance the mechanical strength of plastic.

  Once the modified formula for filling, blending and reinforcement is determined, the specific operation requirements of downstream production equipment are not high. This technical feature determines that the key process of modified plastics production lies in the design of modified formula. From the current situation, the original formula of general-purpose large variety modified plastics is basically in the open state of the market, while the formula of high-performance modified plastics is in the hands of enterprises in various subdivided fields.