JPS5860520A - Condenser - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in metallized film capacitors.

Conventionally, metallized film capacitors, which are made by depositing a low-melting point metal such as aluminium λ or zinc on one or both sides of a biaxially oriented polypropylene film and winding the film, have been known and are conveniently used in various electrical devices. has been done. However, such conventional capacitors have the drawback that their capacitance decreases over time.

An object of the present invention is to provide a capacitor in which this capacitance drop is extremely small.

The present invention has the following features to achieve the above objects.

That is, it is made of a biaxially oriented polypropylene film (hereinafter abbreviated as OPP film) with a surface roughness (Ra) of 0.01 to 0.1 μm and a metal having a melting point of 1100"0 or more deposited on one or both sides of the film. It is characterized by a capacitor mainly consisting of a metal layer.

The metals with a melting point of 1100°C or higher in the present invention include nickel, chromium, nichrome, iron, stainless steel, and titanium.

Palladium, etc. Metals with melting points as low as 1100° C., such as aluminum, zinc, tin, and copper, which have been conventionally used in metallized film capacitors, exhibit large capacitance changes over time.

In addition, the surface roughness (Ra) of the OPP film is 0.01~
It needs to be in the range of 0.1 μm, preferably 0.02 to 0.08 μm. When Ra is smaller than this range, the slippage of the film becomes extremely poor, resulting in poor workability such as winding the element. As a result, wrinkles are likely to form in the element, resulting in a lower breakdown voltage of the capacitor. Conversely, if Ra is larger than this range, the capacitance of the capacitor will decrease significantly.

Note that when forming a capacitor by winding the metallized film provided on both sides of the PP film, the metal layer is
The insulator or dielectric material interposed between the front metal layer and the back metal layer is not particularly limited, but an OPP film is preferable.゛Again.

The insulator or dielectric preferably has a surface roughness of 00
1 to 0.1 μm, preferably 0.02 to 0.08 μm. First, the ash content is 30 pIpm or less (preferably 20 pIpm)
pm or less), and a polypropylene raw material with an intact degree of 97% or more is melted and made into a sheet.

This is rapidly cooled to 20 to 60°C and solidified.

Next, this sheet was heated to 120-145°C and stretched 4.5-5.5 times in the longitudinal direction, and immediately stretched 20-40°C.
Cool to ℃. Next, this sheet is 150-165
8.5 to 10 times in the width direction by heating to 0° and then stretching to 150 to 16 times while allowing relaxation of 4 to 10 inches in the width direction.
Heat treatment is performed at 5°C for 2 to 20 seconds, and then slowly cooled to room temperature. In this way Ra increases, Q 1~0.1 pm
, preferably OPP films with O,o 2 to 0.08 pm. This OPP film is placed in a nitrogen atmosphere, and one side of the film is subjected to a corona discharge treatment with an electric energy amount of 1000 to 6000 J/m.Next, this film is set in an electron beam evaporation device, and the film is discharged. A metal with a melting point of 1,100°C or more is vapor-deposited on the treated surface. A capacitor element is made by steaming. The element is then pressed, heat treated, end-face sealed, and lead wires attached according to conventional methods to form a capacitor. do.

The present invention provides OPP with surface roughness -(Ra) in a specific range.
By combining a film and a specific high-melting point metal to form a capacitor, the capacitor's capacitance decreases little and its breakdown voltage increases.

Next, one measurement method used in the present invention will be summarized.

(1) Surface roughness Ra) Based on J Engineering S B12O3-1976. The cutoff is 0.38 mm.

(2) Capacitance reduction rate (ΔC) of capacitor 30μF
Make a capacitor, place it in an atmosphere at 85°C, charge it with HC 425V, and keep it for 500 hours. 50
Measure the capacity after 0 hours, divide the decrease from the initial capacity by the initial capacity, multiply by 100, and display the result. Naturally, the smaller the capacitance reduction rate, the better the capacitor.

(3) Capacitor breakdown voltage OPP film with a thickness of 8 μm and a metal film resistance of 3Ω/
Vapor-deposit it to form a mouth and roll it around to make a capacity of 60
Make a μF capacitor element.

This is charged at a boost rate of 100 V/sec, and the voltage at which the capacitor breaks down is defined as the breakdown voltage. In the case of a good element, this value usually shows 900 or more, but if the film has poor slippage and there are wrinkles inside the element, this value will decrease. The higher the breakdown voltage, the better the capacitor.

Next, the present invention will be explained based on two examples.O Example 1 Commercially available polypropylene plasticine for condensers (melt index 2 baths/10 minutes. Isotactic degree 97.
8%) was fed into an extruder and melt-extruded at 270°C into a sheet, which was then wound around a cooling drum with a surface temperature of 30°C to cool and solidify.

When this sheet was stretched 4.5 times in the longitudinal direction, the stretching temperature was varied within the range of 125 to 155°C. This film was guided to a stenter and stretched 9 times in the width direction at a stretching temperature of 160°C, and then 160° while giving 5 inches of relaxation in the width direction.
Heat treated with C and slowly cooled to form a PP with a thickness of 8 μm.
Films with different average surface roughness (Ra) were made by changing the longitudinal stretching temperature.

The cholera film was placed in an electron beam vacuum evaporation apparatus, and various metals were evaporated onto the corona discharge treated surface so that the film resistance was 3Ω/mouth. This vapor-deposited film was slit and passed through an element winding machine to produce seven capacitor elements.Furthermore, end faces were sealed and lead wires were attached by conventional methods to produce a capacitor with a capacitance of 50 μF. The characteristics of these capacitors are summarized below.

Invention i o, os nickel 1455
2.8 940z20.04 Chrome 18
90 2.6 9501ro 0.04 Titanium 1
675 2.6 950 Comparative Example 1 0.004
Nickel 1455 2.7' 80
0z 2 0.15 j45
5 6.8 910z30.03
Aluminum, Ni 660 4.2
From the results of 940 or higher, the surface roughness (Ra) of the OPP film is set in the range of O-01 to 0.1 pm, preferably 0.02 to 0.08 μm, and the melting point is set to 11.
It can be seen that capacitors made by vapor-depositing metal at temperatures above 00°C have little capacity loss and high breakdown voltage, making them excellent capacitors.

Patent Applicant Toshi Co., Ltd. Procedures Amendment (Method) % Formula % (1. Indication of the case Patent Application No. 158187 of 1982 2. Name of the invention Capacitor 3. Person making the amendment Relationship with the case Patent application Address: 2-2-4° Nihonbashi Muromachi, Chuo-ku, Tokyo
Amendment order +7) Date: February 23, 1982 (shipment date)5, Number of inventions increased by amendment &L6,
Column ``Title of the Invention'' of the specification to be amended (1) ``Contin'' in the second line of page 1 of the specification is amended to ``condenser''.

Claims (1)

[Claims] It mainly consists of a biaxially oriented polypropylene film with (11 surface roughness Ra) of 0.01 to 0.1 pm, and a metal layer made of a metal with a melting point of 1100°C or more deposited on one or both sides of the film. condenser.