树脂

树脂有天然树脂和合成树脂之分。天然树脂是指由自然界中动植物分泌物所得的无定形有机物质，如松香、琥珀、虫胶等。合成树脂是指由简单有机物经化学合成或某些天然产物经化学反应而得到的树脂产物，如酚醛树脂、聚氯乙烯树脂等，其中合成树脂是塑料的主要成分。

按合成反应

按此方法可将树脂分为加聚物和缩聚物。加聚物是指由加成聚合反应制得的聚合物，其链节结构的化学式与单体的分子式相同，如聚乙烯、聚苯乙烯、聚四氟乙烯等。

缩聚物是指由缩合聚合反应制得的聚合物，其结构单元的化学式与单体的分子式不同，如酚醛树脂、聚酯树脂、聚酰胺树脂等。

Resins are made from natural resins and synthetic resins. Natural resins are amorphous organic substances, such as rosin, amber and shellac, obtained from the secretions of plants and animals in nature. Synthetic resin is to point to by some simple organic compounds by chemical synthesis or natural products by the reaction of a chemical resin products, such as phenolic resin, PVC resin, etc., the plastic is the main component of synthetic resin.

Synthetic reaction

According to this method, the resin can be divided into addition polymer and condensation polymer. A polymer is a polymer produced by addition polymerization. The chemical formula of its chain structure is the same as that of a monomer, such as polyethylene, polystyrene and polytetrafluoroethylene.

Polycondensation is a kind of polymer produced by condensation polymerization. The chemical formula of its structural unit is different from that of the monomer, such as phenolic resin, polyester resin and polyamide resin.