Method for preparing PVC heat stabilizer by taking vermiculite as raw material

Abstract

The invention provides a method for preparing a PVC heat stabilizer through the steps that lamellar silica tetrahedrons and a refabricated lamellar alumina octahedron are obtained by taking ore as a raw material, utilizing the lamellar structure characteristic of vermiculite and removing an alumina octahedron layer between two silica tetrahedron layers, layer splitting of the vermiculite is achieved. Particularly, the method comprises the steps that the vermiculite ore is subjected to microwave expansion to obtain expanded vermiculite; a nano-scale vermiculite flake is obtained by means of ion stirring stripping; the solid lamellar silica (silica tetrahedrons) are obtained according to the characteristics that the silica tetrahedrons are insoluble in acid and the alumina octahedron is soluble in acid by splitting the vermiculite through acid dissolving; iron ions in an acid solution are removed through a graded precipitation method, impurities such as salt ions are removed through quick nucleation and water washing, crystal growth is controlled through a hydrothermal method, and the nano-scale lamellar hydroxide (alumina octahedron) is obtained; the obtained silica and hydroxide successfully achieve mixing of a heat stabilizer and PVC through a solvent replacement and dispersion method, and the agglomeration and redispersion problems of the nano-scale silica and hydroxide are solved. According to the method, the PVC heat stabilizer is prepared by selecting the advantageous mineral vermiculite in China as the raw material, and the advantages of being wide in raw material source, low in cost, simple in process, non-toxic, easy to apply and popularize and the like are achieved; in addition, the efficient heat stabilizer is prepared from the original ore vermiculite, the defects of existing toxic heat stabilizers which are high in price or contain lead are overcome.

Description

[0001] Technical field: [0002] The invention relates to a method for preparing a PVC heat stabilizer using vermiculite as a raw material, in particular to a method for preparing a PVC heat stabilizer, in particular to a non-toxic heat stabilizer special for PVC pipes. [0003] Background technique: [0004] Polyvinyl chloride (PVC) resin is one of the five general plastics (PE polyethylene, PP polypropylene, PVC polyvinyl chloride, PS polystyrene, ABS), and it is a kind of thermoplastic with a wide range of applications. PVC material has high mechanical strength, low price, good chemical resistance (resistant to concentrated hydrochloric acid, 90% sulfuric acid, 60% nitric acid and 20% sodium hydroxide), good electrical insulation and hard to burn (Flame retardant value above 40) and other advantages, with stable physical and chemical properties, insoluble in water, alcohol, gasoline, low gas and moisture leakage, etc. It is widely used in engineering construction, food packaging, ...

AI Technical Summary

Problems solved by technology

[0006] In the 1930s, the appearance of lead salts first solved the problem of thermal degradation of PVC, and was also the first heat stabilizer to be used. However, with the enhancement of people's awareness of environmental protection, its high toxicity and serious pollution have greatly limited its application.

[0007] my country's heat stabilizer industry is still facing many problems, such as lack of sufficient research and development funds, lack of high-level professionals, disconnection between scientific research and production; insufficient original innovation of products, few varieties; slow environmental protection process, unreasonable product structure; Small production scale, uneven product quality, etc.

The existence of the above problems seriously limits the development of my country's heat stabilizer industry

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