Biaxially stretched polypropylene film for capacitor, deposition-coated film obtained from the same, and capacitor employing the same

A polypropylene film, biaxial stretching technology, applied in the direction of fixed capacitor dielectric, capacitor, fixed capacitor, etc., to achieve the effects of excellent resistance, excellent processing adaptability, and excellent dimensional stability

Active Publication Date: 2010-09-29
OJI PAPER CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

This patented BOPP films have good properties like being able to maintain their shape even when subjecting them under pressure or tension during production processes. They are suitable materials for use in electronic devices that require reliable performance over extreme conditions. Additionally they provide superior electrical insulation compared to other types of plastics commonly used due to its unique structure and chemical composition.

Problems solved by technology

This patents describes different methods for improving the performance of polyolefin materials used in electronic devices like capacitors. These techniques include adjustment of chemical structure parameters, control over orientation conditions, creation of fine particles on the surfaces of these materials through electrostatic spinning processes, coating them with metal foils containing beta crystars, adding extra layers between them, modifying their tensile elongations under stress loads, optimizing the process window, minimizing defects caused by bending stresses, maintaining good flexibility against thermally induced changes, achieving both large and ultrafiltrative membranes, and enhancing electric insulation and mechanical strength without compromising productivity.

Method used

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  • Biaxially stretched polypropylene film for capacitor, deposition-coated film obtained from the same, and capacitor employing the same
  • Biaxially stretched polypropylene film for capacitor, deposition-coated film obtained from the same, and capacitor employing the same
  • Biaxially stretched polypropylene film for capacitor, deposition-coated film obtained from the same, and capacitor employing the same

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no. 2 approach

[0104] The molecular characteristics (molecular weight, molecular weight distribution, composition of molecular weight distribution, tacticity) of the biaxially stretched polypropylene film of the first or second embodiment (hereinafter referred to as the present embodiment) are not values ​​of the resin itself for film production , must be the value of the resin that formed the thin film after the film forming process. Such a resin formed into a film undergoes a lot of thermal and oxidative deterioration, shear deterioration, elongation deterioration, etc. in the extruder during the film forming process, and a lot of thermal and oxidative deterioration occurs in the stretching process. , elongation deterioration, etc., thus aggravating the decomposition. Along with this, the molecular weight, molecular weight distribution, and tacticity are often different between the raw material resin and the film-forming resin after film formation. It is a molecular characteristic of the ...

Embodiment 1

[0202]Resin A pellets manufactured by Company A are supplied to an extruder, melted at a resin temperature of 250°C, extruded through a T-die, wound up on a metal drum whose surface temperature is kept at 95°C, and solidified. A cast green sheet having a thickness of about 250 μm was produced. Next, the unstretched cast green sheet was stretched to 5 times in the longitudinal direction at a temperature of 140° C., immediately cooled to room temperature, and then stretched to 10 times in the transverse direction at a temperature of 165° C. with a tenter, A thin biaxially stretched polypropylene film with a thickness of 5.0 µm was obtained. The molecular properties and melting points of the obtained films are summarized in Table 1, and the evaluation results are also summarized in Table 3.

Embodiment 2

[0210] The evaluation of the film obtained from the molecular characteristics of Example 1 is within the practically preferred range, but in order to further improve the mechanical thermal stability and high-temperature withstand voltage characteristics, a resin A based on resin A that maintains tacticity was used. In the case of Resin E manufactured by Company C, obtained by further adjusting the structure of the molecular weight distribution by a polymerization method, a biaxially stretched polypropylene film was produced by the following method.

[0211] Resin E pellets manufactured by Company C were supplied to an extruder, melted at a resin temperature of 250°C, extruded using a T-die, wound up on a metal drum whose surface temperature was kept at 90°C, and solidified. A cast green sheet having a thickness of about 250 μm was produced. Next, the unstretched cast green sheet was stretched to 5 times in the longitudinal direction at a temperature of 140° C., immediately coo...

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Abstract

A biaxially stretched polypropylene film for capacitors which is a film having a thickness of 1.0-8.0 [mu]m obtained by biaxially stretching a cast raw sheet of a crystalline isotactic polypropylene resin. It is characterized by having a weight-average molecular weight (Mw), as determined by gel permeation chromatography, of 250,000-450,000 and a molecular-weight distribution (Mw/Mn) of 4-7 and giving a molecular-weight distribution curve in which the value obtained by subtracting the differential distribution value corresponding to a logarithmic molecular weight of 6 from the differential distribution value corresponding to a logarithmic molecular weight of 4.5 is from 2% to 15%. The film is further characterized by having a mesopentad content, as determined by high-temperature nuclear magnetic resonance spectroscopy, of from 94% to 98%, excluding 98%.

Description

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Claims

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Application Information

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Owner OJI PAPER CO LTD
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