1. Synthetic resin is the main component of plastic, and its content in plastic is generally 40% to 100%. Due to the large content and the properties of resins that often determine the properties of plastics, people often regard resins as synonymous with plastics. For example, polyvinyl chloride resin is confused with polyvinyl chloride plastic, phenolic resin and phenolic plastic. In fact, resin and plastic are two different concepts. Resin is a raw, unprocessed polymer that is used not only to make plastics, but also as a raw material for coatings, adhesives, and synthetic fibers. In addition to a very small part of plastics containing 100% resin, the vast majority of plastics need to add other substances in addition to the main component resin.

2. Filler

Fillers, also known as fillers, can improve the strength and heat resistance of plastics and reduce costs. For example, adding wood powder to phenolic resin can greatly reduce the cost, making phenolic plastic one of the cheapest plastics, and at the same time, it can significantly improve the mechanical strength. Fillers can be divided into organic fillers and inorganic fillers, the former such as wood flour, rags, paper and various fabric fibers, etc., the latter such as glass fiber, diatomaceous earth, asbestos, carbon black and so on.

3. Plasticizer

Plasticizers can increase the plasticity and softness of plastics, reduce brittleness, and make plastics easy to process and shape. Plasticizers are generally resin-miscible, non-toxic, odorless, high-boiling organic compounds that are stable to light and heat. The most commonly used are phthalates. For example, when producing polyvinyl chloride plastics, if more plasticizers are added, soft polyvinyl chloride plastics can be obtained. . < p="">

4. Stabilizer

In order to prevent the synthetic resin from being decomposed and destroyed by light and heat during processing and use, and to prolong the service life, a stabilizer should be added to the plastic. Commonly used are stearate, epoxy resin and so on.

5. Colorants

Colorants can give plastics a variety of bright, beautiful colors. Organic dyes and inorganic pigments are commonly used as colorants.

6. Lubricant

The role of the lubricant is to prevent the plastic from sticking to the metal mold during molding, and to make the surface of the plastic smooth and beautiful. Commonly used lubricants are stearic acid and its calcium and magnesium salts. In addition to the above additives, flame retardants, foaming agents, antistatic agents, etc. can also be added to the plastic.