Preparation method for PET and PBT polyester alloy

Abstract

The invention relates to a preparation method for a PET and PBT polyester alloy and belongs to the field of plastic preparation. The method comprises the following steps: (1) preparing polyester alloy granules: taking PET and PBT, drying and dehumidifying, and then uniformly mixing with auxiliaries, extruding the mixture through a double screw extrusion machine, quenching, shearing and pelletizing; (2) preparing injection molding sample strips: melting and extruding the prepared granules, drying and injection-molding into various standard sample strips. On the basis of the improvement for the traditional alloy preparation technology, the alloy prepared according to the method provided by the invention has obviously promoted tensile strength, bending strength, notched impact strength and hardness, the preparation technology is simple and the preparation method is suitable for popularization and application.

Description

technical field [0001] The invention belongs to the field of plastic material preparation, in particular to a preparation method of PET and PBT polyester alloy. Background technique [0002] Polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), which are thermoplastic polymer materials, do not contain non-aromatic unsaturated bonds in their molecular structures. And now polyester in the usual sense refers to the most representative PET. The synthesis process of PET and PBT is similar, and there is mainly PTA method in industrial production: the direct ester of purified terephthalic acid or medium-purity terephthalic acid and ethylene glycol / 1,4-butanediol as raw materials. [0003] Since its inception, PET has been mainly used in the fields of fiber spinning and clothing. It can also maintain excellent physical properties in a wide temperature range, and has high strength, excellent weather resistance, solvent resistance and electrical insulation, so it ha...

AI Technical Summary

Problems solved by technology

Homogeneous nucleation is the orderly arrangement of chain bundles or folded chains generated by the thermal motion of the melt molecular segments themselves as crystal nuclei, and the required temperature is usually low, but PET has poor chain flexibility at low temperatures and is difficult to self-nucleate , that is, homogeneous nucleation, the entire crystallization process of PET will also become very slow because of the difficulty of homogeneous nucleation

Engineering plastic grade PET has high strength, resistance to organic solvents, and good weather resistance, all of which are endowed by its rigid structure with benzene rings, but it is precisely because of this rigid structure that its molecular chains are less flexible. High glass transition temperature hinders the movement of molecular segments, resulting in slow crystallization rate, which further causes problems such as difficult molding processing, high molding temperature, long production cycle, and poor impact performance.