High-temperature resistant ultrathin polypropylene metalized capacitor film for capacitor

Abstract

The invention discloses a high-temperature resistant ultrathin polypropylene metalized capacitor film for a capacitor. The high-temperature resistant ultrathin polypropylene metalized capacitor film is prepared by the following steps of: sucking polypropylene resin particles with the isotacticity of 96 percent in an extruder hopper through a vacuum suction machine, and dissolving the particles to form a viscous-state melt; filtering impurities and non-molten substances in the viscous-state melt by employing a candle filter; casting the melt on a die head to form a flaky melt; adhering the flaky melt to a cooling roller through an air knife, so that the surface layer of the polypropylene melt is cooled and solidified to form a sheet; transversely stretching the sheet to obtain a film; transversely stretching the film to obtain a thin film; cutting a side film which is not stretched, and performing corona treatment to obtain the metalized capacitor film; and dragging the metalized capacitor film of which the breadth accords with the specification into a coil. High-isotacticity polypropylene particles with the isotacticity of over 98 percent are replaced by the conventional polypropylene particles with the isotacticity of 96 percent to produce an ultrathin polypropylene film with the thickness of 3-4mu m, the polypropylene film has excellent physical properties and electrical properties and particularly has high-temperature resistance, when the operating temperature of the coiled capacitor reaches 100 to 115 DEG C, the polypropylene film has high mechanical strength, and the heat shrinkage and the inner haze are reduced.

Description

technical field [0001] The invention relates to a capacitor film, in particular to a high-temperature-resistant ultra-thin polypropylene metallized capacitor film for capacitors. Background technique [0002] High-temperature-resistant polypropylene film for capacitors (hereinafter referred to as high-temperature-resistant film) is mainly used as the dielectric of metallized film capacitors. Under the test condition of 120°C for 15 minutes, the sum of the longitudinal and transverse thermal shrinkage rates is 1-4%. Its capacitors made of dielectric materials can operate safely and stably for a long time at an ambient temperature of 105°C. The high temperature resistant film is made of polypropylene particles with high cleanliness, high isotacticity, and high crystallinity, which are extruded, cast into sheets, stretched longitudinally, stretched transversely, controlled in thickness, corona treated, and harvested under certain process conditions. It is processed by rolling...

AI Technical Summary

Problems solved by technology

[0005] The high-temperature-resistant film used in China mainly relies on imports from foreign companies such as Toray in Japan and Chuangshipu in Germany. At present, only a few domestic manufacturers such as Anhui Tongfeng Electronics Co., Ltd. and Guangdong Xinhui Capacitor Film Factory can produce high-temperature-resistant films. The batch and grade are not as good as foreign countries, and only high-grade (more than 98%) raw materials can be used for production, while high-grade polypropylene particles are protected by foreign patents, which has brought great challenges to domestic companies in the development of high-temperature resistant films for capacitors. difficulty