BOPET for ultra-thin weather-proof balanced type capacitor and manufacturing method thereof

Abstract

The invention discloses a manufacturing method of a BOPET for an ultra-thin weather-proof balanced type capacitor. The BOPET adopts polyester to serve as the major component and comprises an upper surface layer, a sandwich layer and a lower surface layer; the longitudinal and horizontal thermal contraction of the BOPET is 0-2.5 percent; the ratio of the longitudinal thermal contraction rate and the horizontal thermal contraction rate is 0.98-1.12; the dielectric constant is 3.3; and the volume resistance is 1,013-1,017 Omega. The BOPET has the advantages of thin thickness, good heat resistance, high thermal stability, favorable weather ability, long service life, excellent electric insulativity and high electric strength, and is particularly suitable for capacitor dielectric medium.

Description

technical field [0001] The present invention relates to a polyester capacitor film and its manufacturing method, more specifically to a three-layer structure for a weather-resistant capacitor with a thickness of less than 4 μm, excellent thermal stability and electrical insulation performance under high temperature and harsh conditions Polyester film. Background technique [0002] With the development of electrical and electronic to miniaturization and miniaturization, capacitors need to develop towards miniaturization and high capacitance. We have conducted research on the ultra-thinning of the polyester film used as a dielectric for cylindrical capacitors and the reduction of the number of electrical weak points of the film. [0003] The current capacitive film adopts a single-layer structure in order to facilitate ultra-thinning to improve the stability during production. However, in order to increase the surface roughness of the film, improve the electrical properties...

AI Technical Summary

Problems solved by technology

The disadvantage of using a single-layer structure is: after adding additives, the entire film contains additives, not only the amount of additives is large and the cost is high, but more importantly, there will be discs in local areas of the film because the additives cannot be completely dispersed. This may form a very small through-channel in the film, resulting in poor mechanical and electrical properties in the microscopic area of ​​the film, and it is easy to break down at the electrical weak point, which affects the charging life of the capacitor.

Since the polyester film is subject to various thermal stresses when the capacitor is manufactured, coiled and energized, the longitudinal and transverse thermal shrinkage rates of the film are inconsistent, which will lead to the formation of small bulges in the direction of high thermal recovery rate, resulting in increased local internal stress. Greatly reduced capacitor characteristics