Preparation method of rare earth heat stabilizer used for PVC

Abstract

The invention discloses a preparation method of a rare earth heat stabilizer used for PVC, and belongs to the technical field of plastic assistants. The preparation method comprises the following steps: protecting the hydroxyl group of 3-hydroxypropionic acid used as a raw material with trimethylchlorosilane, reacting the hydroxyl group protected 3-hydroxypropionic acid with thionyl chloride to generate acyl chloride, reacting the acyl chloride with glutamic acid to generate an amine substance, oxidizing the amine substsance to obtain a substance containing an amino group and a carboxyl group, saponifying the substance containing an amino group and a carboxyl group, reacting the saponified substance with an inorganic rare earth salt to generate organic rare earth with generated HCl neutralized by the amino group in order to prevent automatic oxidation, mixing the organic rare earth with a heat stabilization assistant, and drying the obtained mixture to obtain the rare earth heat stabilizer used for PVC. The rare earth heat stabilizer used for PVC overcomes the disadvantages of large toxicity, poor initial heat stability and slow speed of existing heat stabilizers, and has the advantages of improvement of the long-term stability and the initial coloring property of the PVC, non-toxicity, environmental protection, low energy consumption, low dosage, low price and broad industrial application prospect.

Description

technical field [0001] The invention discloses a preparation method of a rare earth heat stabilizer for PVC, belonging to the technical field of plastic additives. Background technique [0002] Polyvinyl chloride (PVC) is widely used in various fields because of its excellent mechanical properties and good processing properties, as well as corrosion resistance, aging resistance, low cost, rich raw materials, and mature manufacturing technology. One of the general resins. However, there is a fatal flaw in the processing of PVC, that is, its decomposition temperature is usually lower than its processing temperature. Under a certain temperature or light, PVC is easy to decompose and release hydrogen chloride, and its thermal stability is poor. Therefore, heat stabilizers must be used in PVC processing. [0003] At present, the heat stabilizers commonly used in PVC mainly include lead salts, organotins, metal soaps and rare earths. Lead salt heat stabilizers are the earliest ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention: aiming at the disadvantages that inorganic rare earths have poor initial thermal stability to PVC, poor compatibility with PVC, and relatively serious coloring property, a kind of hydroxy acid and carboxyl group undergoes amination reaction, and then Oxidation of hydroxyl groups into carboxyl groups to obtain substances containing amino groups and carboxyl groups, and then reacting with rare earth salts to obtain organic rare earths, and then supplementing with thermal stability additives to prepare rare earth heat stabilizers for PVC. The present invention first uses 3-hydroxypropyl The acid is used as the raw material, and the hydroxyl group is protected by trimethylchlorosilane, and then reacted with thionyl chloride to form an acid chloride, and then reacted with glutamic acid to form an amine substance, and then oxidized to obtain a substance containing an amine group and a carboxyl group. After saponification, it reacts with inorganic rare earth salts to generate organic rare earths, and the amine groups can neutralize the generated HCl to prevent automatic oxidation. Finally, it is mixed and dried with thermal stability additives to obtain rare earth thermal stabilizers for PVC. Rare earth heat stabilizers for PVC can not only overcome the shortcomings of existing heat stabilizers such as high toxicity and slow initial thermal stability, but also improve the long-term stability and initial coloring of PVC, non-toxic and environmentally friendly, low energy consumption, Less consumption, low price, and broad industrial application prospects