A kind of preparation method of low extraction, high temperature resistant insulating polyester film

Abstract

The invention discloses a preparation method of a low-extraction high-temperature-resistant insulating polyester film. The method comprises the following steps: (1) preparing a polyester; (2) performing extrusion slicing: performing melt extrusion slicing on the product obtained in the step (1) by using a twin-screw extruder; (3) performing solid phase tackifying: performing tackifying by using asolid phase tackifying device until intrinsic viscosity of polyester chips reaches 0.7-1.3 dL / g; (4) performing melt extrusion, and performing casting: performing pre-crystallization drying on the polyester chips and an appropriate amount of auxiliary materials, performing melt extrusion, and performing casting; and (5) performing biaxial stretching to form the film: performing longitudinal stretching on the cast piece, performing transverse stretching, and performing traction rolling to obtain the insulating polyester film, wherein a catalyst used in polycondensation in the step (1) is a complex of metal titanium and ligand bis(diphenylphosphinoethyl)amine. The method provided by the invention adopts a specific raw material formula and a production process, and the obtained insulating polyester film has the advantages of a low extract and high heat resistance, and is particularly suitable for insulating polyester films used for electrical machines and motors.

Description

technical field [0001] The invention relates to the field of polyester production, in particular to a low-extraction, high-temperature-resistant insulating polyester film, a preparation method thereof, and an application in producing heat-resistant insulating films. Background technique [0002] Biaxially oriented polyester film for heat-resistant insulating motors has excellent properties such as high long-term heat resistance index and excellent insulation performance, and is widely used in the manufacture and production of hermetic compressors and hermetic motors for air conditioners, refrigerators, freezers and other household appliances. In recent years, with the development of the economy and the shift of the world's manufacturing structure, the world's major air-conditioning compressor manufacturers have set up factories in China or expanded their production capacity to meet the growing market demand. [0003] The raw material of polyester film—polyester chip is made ...

AI Technical Summary

Problems solved by technology

[0005] Japanese patent JP12-7767 reports a method to reduce the oligomer content in the product polyester by controlling the terminal hydroxyl content of the prepolymer, mainly by adjusting the ratio of monomers, reaction time, esterification temperature, esterification time, Pressure, etc. to control the hydroxyl content, and further adjust the intrinsic viscosity of polyester chips, but there are many factors affecting the hydroxyl content, it is difficult to effectively control in actual operation

Moreover, the reduction of the amount of hydroxyl end of polyester means the increase of carboxyl group as one end end, which will adversely affect the heat resistance of polyester film and the durability of long-term use, so it is not practical.

[0006] Chinese patent CN106626679B discloses a high-strength biaxially stretched PEN film and its preparation method, wherein in order to reduce the content of oligomers in the polyester film, a platinum catalyst is added to the front of the air change box during heat setting, and the Oligomers are catalytically decomposed into water and carbon dioxide, but on the one hand, the platinum catalyst is expensive, on the other hand, the catalytic degradation of the film may adversely affect the mechanical properties and insulation of the film

However, the content of oligomers in the obtained polyester is still high, reaching more than 2%, which is difficult to meet the actual needs of insulating films for motors and motors, and the addition of these components may affect the insulation and heat resistance of polyester films. will adversely affect

[0008] Chinese patent CN104603185A discloses a polyester film that shields oligomers through an undercoat layer. This patent document is mainly devoted to the performance research of optical films, that is, the production process. The formula is aimed at the haze, transparency, and whitening properties of polyester products. Influence, but did not study the heat resistance and insulation properties of polyester film

Moreover, if the coating is used to inhibit the migration and precipitation of oligomers, even if a small damage does not affect the quality, it will affect the inhibition performance, and the precipitation will occur concentratedly at this place, which is even more unsuitable for the insulating film for electrode motors.

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