JPS593910A - 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 In the present invention, a metal such as aluminum is deposited on a biaxially oriented polypropylene film. This invention relates to an improvement in a capacitor formed by rotating a so-called metallized biaxially oriented polypropylene film.

Conventionally, this type of capacitor has had many opportunities to undergo so-called winding operations, such as slitting the film into small widths and winding the element. The interlayer stability between the films is improved by making the film grow larger and creating unevenness.

It has been put into practical use for various electrical devices. However, capacitors made of films with unevenness formed on the film surface by such conventional methods have a drawback in that the capacitance decreases as the film is ingested.

The object of the present invention is to improve this drawback and provide a capacitor with little change in capacitance.

In order to achieve the above object, the present invention has the following configuration: AMI! 0.01 to 100 parts by weight of silicone oil containing at least one group selected from the group consisting of a carboxyl group, a phenyl group, a hydroxyl group, and an alkyl group, based on 100 parts by weight of polypropylene.
biaxially oriented polypropylene film containing 2 parts by weight and subjected to corona discharge treatment on at least one side;
The capacitor is characterized by a metal layer deposited on the corona discharge treated side of the film.

Biaxially oriented polypropylene film (hereinafter referred to as QP) of the present invention
A biaxially stretched film made of polypropylene (abbreviated as P film) is most preferably a biaxially stretched film made of polypropylene. Homopolymers such as pentene-1 or binary or ternary copolymers of these with each other (e.g. ethylene, propylene copolymers).

It may also be a biaxially stretched film made of a copolymer or a blend (a terpolymer of ethylene and propylene butene) or a copolymer or blend with other monomers, or a composite film containing layers of these films.

In addition, the OFF film may contain other thermoplastic polymers and various known additives (stabilizers, antioxidants, inorganic lubricants, , nucleating agent, crosslinking agent, etc.) may be added and mixed.

The silicone oil applied to the present invention is dimethylpolysiloxane Me, which is represented by the following structural formula.
Me Me Mθ Me
Me (where 0Mθ is a methyl group), or at least one Me in the above structural formula is an amino group ((
-R1)n-NH, hereinafter abbreviated as amino-modified],
Carbo (hereinafter abbreviated as phenyl modified)], hydroxyl group [(-
R+) OH, hereinafter abbreviated as alcohol denaturation].

These are organopolysiloxanes replaced with alkyl groups (-R, -CH, hereinafter abbreviated as alkyl modification), or copolymers thereof.

n is 0 or 1. R,, R, is a hydrocarbon group having 1 to 2 carbon atoms, R8 is hydrogen or a hydrocarbon group having 1 to 2 carbon atoms,
The repeating unit of ÷o-8i+ is 1 to 5o! is desirable.

Among these modified silicone oils, phenyl-modified silicone oils and alkyl-modified silicone oils are particularly preferred.

The silicone oil mentioned above is polypropylene 1o.

It is necessary to add 0.01 to 2 parts by weight based on the weight. If the amount added is less than 0.01 parts by weight, the effect on the film will be poor.

This is undesirable because the breakdown voltage of the capacitor decreases due to wrinkles that occur during the slitting process and the element winding process.Additionally, if it exceeds 2 parts by weight, tanδ increases and the adhesion of the metal evaporated film decreases. death.

The capacitance of the capacitor changes rapidly, which is not desirable.

On at least one surface of the OPP film of the present invention,
Corona discharge treatment must be performed. By carrying out this treatment, the silicone oil diffuses onto the film surface, and the surface has a sufficient sliding effect and adhesion strength to the metal vapor deposited film. To obtain the OPP film of the present invention from a raw material composition made of raw polypropylene containing silicone oil, first, the raw material composition is extruded in a molten state into a film using an extruder, and is wound around a cooling drum to form a sheet. Stretched film. After the obtained unstretched film is stretched 3 to 10 times in the machine direction and further stretched 5 to 12 times in the transverse direction, it is immediately subjected to a relaxation heat treatment, and at least one surface of the film is subjected to a corona discharge treatment. This can be obtained by applying Note that the corona discharge treatment may be a well-known corona discharge treatment, but the treatment is performed in an inert gas such as nitrogen and the film temperature during treatment is 40°.
It is particularly preferable to maintain it at C or higher. Also.

This corona discharge treatment is not limited to being applied after forming a biaxially stretched film, but may be applied after forming an unstretched film or a uniaxially stretched film.

Also, metal deposition on corona discharge treated surfaces.

The metal to be vapor-deposited is not particularly limited, but aluminum and zinc are usually preferably used. The vapor deposition method is not particularly limited either, and may be an electric heating fusion vapor deposition method.

Ion/beam evaporation method-sputtering method or ion planing method can be used.

The thickness of the deposited film is not particularly limited, but is 100 to 5000
It is desirable that it be within the range of A. The thus deposited film is wound to form a capacitor, but it may also be impregnated with oil to form a so-called oil-immersed capacitor. Alternatively, only both end surfaces of the condenser may be impregnated with oil or wax, and the central portion may be left as a dry trench (not impregnated with oil or the like).

The capacitor referred to in the present invention includes a dry type, an oil immersion type, or a combination thereof.

Next, a specific example of the manufacturing method of the capacitor according to the present invention will be explained. The surface of an OPP film made of raw material polypropylene containing silicone oil is subjected to the above-mentioned corona discharge treatment, and the film is set in a vacuum deposition apparatus to deposit aluminum onto the surface of the film. The vapor-deposited film is slit to an appropriate width, two layers are rolled together to form a capacitor element, both ends are sealed, and lead wires are attached to form a capacitor.

The capacitor of the present invention thus obtained exhibits excellent effects in that there is little variation in capacitance when the capacitor is manufactured, and there is little change in capacitance during oral administration.

Note that the average roughness of both surfaces of the OPP film used in the present invention is not particularly limited, but the roughness R) is 0.
．． It is desirable that the roughness is 1 μm or less, and the smaller the roughness, the more remarkable the effects of the present invention will be. That is, Ra is 01μm
In the following cases, with conventional film, the surface is extremely deteriorated and workability for slitting and element winding is poor, and
The breakdown voltage of a capacitor decreases due to fine wrinkles, etc. However, in the film of the present invention, a specific amount of a specific silicone oil is added, so even a film with a very small Ra has no problem with the breakdown voltage and the capacitance is maintained. Capacitors with small changes can be obtained.

Next, a method for measuring characteristic values in the present invention will be described.

(1) Average surface roughness Ra) According to JAS B06°01-1976. The cutoff is 00B barrel.

(2) Capacitance reduction rate (ΔC) of capacitor 60μF
Make a capacitor, place it in an atmosphere of 85°0, charge it with AC42!5V, and keep it for 500 hours. 50
The capacity after 0 hours is measured, and the decrease from the initial capacity is divided by the initial capacity, multiplied by 100, and expressed as %fi. Naturally, the smaller the rate of capacitance decrease, the better the capacitor is.

(3) Breakdown voltage of capacitor Aluminum is vapor-deposited on an OPP film with a thickness of 8 μm so that the film resistance is 3 Ω/hole, and the film is wound to form a capacitor element with a capacitance of 30 μF. In addition, AC1
The capacitor is charged at a boost rate of 00 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 900V or more, but if the element has "wrinkles" or the like, this value decreases. Naturally, the higher the breakdown voltage, the better the capacitor.

(4) Blocking shear force (evaluation of blocking resistance) Sample films of 3 m in width x length were stacked over a length of 4 an, and heated at 40 g/(2) in an atmosphere of 4 D'0, 80 S RH. ' After being left for 24 hours under a load of .

Measure the force required for shear peeling using a tensile tester.

The smaller the value, the better the blocking resistance.

Examples 1-3. Comparative Examples 1 to 3 Phenyl-modified silicone oil ('
Viscosity at 50°0 1[]0[1 centistokes)00
Experimental levels were taken in the range of 5 to 2.0 parts by weight, heated about 3 times in a super mixer, and fed to the extruder separately for each level. 1st, melted at 250°C and cooled to 30"0. The mixture was cooled and solidified on a chill roll to obtain a sheet-like film with a thickness of 400 μm.

While heating this film to 15°0°C,
Stretched twice. This stretched film was guided to a Stenck type horizontal stretching machine and stretched 10 times in the width direction at a stretching temperature of 160°C.
Next, after 5% relaxation in the width direction, heat treatment was performed at 155'o, followed by slow cooling with air at 40°C to form an OPP with a thickness of 8 μm.
Got the film. One side of this film was subjected to a conventional corona discharge treatment. Set each of these films into a vacuum evaporation device,
It was deposited on the corona discharge treated surface so as to form a rough surface. This vapor-deposited film was slit and passed through an element winding machine to produce a capacitor element, and the end face was sealed and an IJ-cord wire was attached in a conventional manner to produce a capacitor with a capacity of 50 IIF. The characteristics of these capacitors and the characteristics of the film before vapor deposition are shown in Table 1 as Examples 1 to 3.

Next, only the raw material polypropylene used in Example 1 was supplied to the extruder, melted at 25D'a, cooled and solidified in the chill roll temperature range of 60°C to 95°C, and was made to a thickness of 400μ6I.
A sheet-like film was obtained. and.

Stretching, relaxation, and heat treatment conditions in length and width directions.

A capacitor was manufactured under the same conditions as in Example 1, including surface treatment conditions and metal vapor deposition conditions. The characteristics of these capacitors and the characteristics of the films before vapor deposition are shown in Table 1 as Comparative Examples 1 to 6. Note that Comparative Example 1 has a surface roughness Ra of 0.
03, tearing occurred due to blocking during metal vapor deposition.

Table 1 As is clear from the results in Table 1, the conventional capacitors had a large capacity drop, but the capacitor of the present invention was excellent in that the capacity drop was very small.

Claims (1)

[Claims] 0.01 to 2 silicone oil containing at least one group of amino group, carboxyl group, phenyl group, hydroxyl group, and alkyl group per 100 parts by weight of polypropylene
1. A capacitor comprising a biaxially oriented polypropylene film which contains a biaxially oriented polypropylene film containing 20% by weight and which has been subjected to a corona discharge treatment on at least one side, and a metal layer deposited on the corona discharge treated side of the film.