JP2000351919A - Dielectric coating material for film capacitor, its cured material and use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a solvent-free dielectric coating material for film capacitor improved in electrical characteristics such as electrostatic capacity and dielectric loss tangent, heat resistance and moisture resistance, its cured material, an element for film capacitors using the cured material as a dielectric material layer and a laminated film capacitor. SOLUTION: This dielectric coating material for film capacitors comprises a fumaric acid diester, a vinyl-based monomer having at least two or more double bonds between carbons in one molecule and a polymerization initiator. This dielectric material for film capacitors is obtained by curing the coating material. This element for film capacitors is obtained by forming the dielectric material layer on a metallized film face. This laminated film capacitor is obtained by laminating two or more layers of the element.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dielectric paint for a film capacitor, which has no solvent and has improved electrical properties such as capacitance and dielectric loss tangent, heat resistance and moisture resistance, and a cured product thereof.
The present invention relates to an element for a film capacitor having a cured product as a dielectric layer and a laminated film capacitor.

[0002]

2. Description of the Related Art In recent years, with the increase in the density of electronic components using surface mounting technology, demands for smaller and lower cost electronic components have been increasing. From the same viewpoint, the development of products for capacitors has been progressing one after another. In particular, conventionally used film capacitors use polyethylene terephthalate, polyphenylene sulphite, polyethylene naphthalate, etc. as a base film, aluminum is deposited on both sides, and a polycarbonate or polyphenylene oxide is further used as a dielectric layer thereon. Have been used for film capacitor dielectrics. When the dielectric layer is formed, it is a process of coating as a solution diluted with an organic solvent and evaporating the organic solvent.
On the other hand, in recent years, there has been an increasing trend in the entire industry to review the use of organic solvents in terms of toxicity, waste of resource and energy, or cost, and there has been a strong demand for reducing organic solvents. In response to this demand, for example, JP-A-9-194759 discloses a solvent-free type dielectric coating for film capacitors containing a (meth) acrylate compound, a vinyl ether compound and a photopolymerization initiator, and a cured product thereof. Have been.

[0003]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
Japanese Patent Application Laid-Open No. 194759/1992 is a process in which a film capacitor can be manufactured without using a solvent, but has a problem that a cured product has a large dielectric loss tangent and low heat resistance and low moisture resistance. The object of the present invention is a solvent-free, electrostatic capacity, electrical properties such as dielectric loss tangent, heat resistance, improved moisture resistance of the film capacitor dielectric paint, cured product thereof,
An object of the present invention is to provide a film capacitor element using a cured product as a dielectric layer and a laminated film capacitor obtained by laminating the same.

[0004]

The first invention is directed to a dielectric for a film capacitor comprising a fumaric acid diester, a vinyl monomer having at least two carbon-carbon double bonds in one molecule, and a polymerization initiator. Body paint. A second invention is a dielectric for a film capacitor obtained by curing the dielectric paint for a film capacitor of the first invention. A third invention provides that at least one surface of the metallized film has
A film capacitor element comprising the film capacitor dielectric layer of the second invention. A fourth invention is a laminated film capacitor obtained by laminating the film capacitor elements of the third invention.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The dielectric coating for a film capacitor of the present invention contains a fumaric acid diester, a vinyl monomer having at least two carbon-carbon double bonds in one molecule, and a polymerization initiator. The fumaric acid diester can be used for the purpose of the present invention, in particular, as long as it can provide a dielectric coating for a film capacitor with improved electrical properties such as capacitance and dielectric loss tangent and a cured product thereof, and all known products can be used. Is preferably a fumaric acid diester represented by the following general formula (1). XOOC-CH = CH-COOY (1) (wherein X is a branched alkyl group or substituted branched alkyl group having 3 to 8 carbon atoms, or a cycloalkyl group or substituted cycloalkyl having 4 to 8 carbon atoms) Y represents an alkyl group
Represents a branched or substituted alkyl group having 3 to 8 carbon atoms, a cycloalkyl group or a substituted cycloalkyl group having 4 to 8 carbon atoms. )

Specific examples of fumaric acid diester include, for example, diisopropyl fumarate, di-sec-butyl fumarate, di-tert-butyl fumarate, diisobutyl fumarate, di-sec-amyl fumarate, di-t
ert-amyl fumarate, di-4-methyl-2-pentyl fumarate, di-sec-amyl fumarate, di-
3-pentyl fumarate, bis (2,4-dimethyl-3
Pentyl) fumarate, isopropyl-sec-butyl fumarate, tert-butyl-4-methyl-2-pentyl fumarate, isopropyl-tert-butyl fumarate, sec-butyl-tert-butyl fumarate, sec-butyl-tert- Amyl fumarate, di-4-methyl-pentyl fumarate, tert-butyl-isoamyl fumarate, dicyclobutyl fumarate,
Dicyclopentyl fumarate, dicyclohexyl fumarate, dicycloheptyl fumarate, dicyclooctyl fumarate, bis (4-chloro-cyclohexyl) fumarate, bis (4-tert-butyl-cyclohexyl) fumarate, diisobornyl fumarate, Dibornyl fumarate, dinorbonyl fumarate, isopropyl-cyclobutyl fumarate, 1-chloro-2-propyl-cyclopentyl fumarate, 1,3-dichloro-2-
Propyl-cyclohexyl fumarate, sec-butyl-cyclohexyl fumarate, 3-chloro-2-butyl-cyclohexyl fumarate, tert-butyl-cyclopentyl fumarate, tert-butyl cyclohexyl fumarate, sec-amyl-cyclohexyl fumarate, 3 -Pentyl-bornyl fumarate, 2,3-dimethyl-3-pentyl-adamantyl fumarate, te
Examples thereof include rt-amyl-cyclohexyl fumarate, neopentyl-cyclopentyl fumarate, 4-methyl-2-pentyl-cyclohexyl fumarate, and 2-ethyl-hexyl-cyclohexyl fumarate. Among them, diisopropyl fumarate, di-tert-butyl fumarate,
Dicyclohexyl fumarate is particularly preferred. In the present invention, the above fumaric acid diesters can be used alone or in combination of two or more.

In a vinyl monomer having at least two carbon-carbon double bonds in one molecule used in the present invention (hereinafter abbreviated as a crosslinked vinyl monomer), a carbon-carbon double bond Examples of the group include a vinyl group, an acryloyl group, a methacryloyl group, a maleimide group, a vinyl ether group, a vinyl ester group, an allyl ether group, and an allyl ester group.

Specific examples of the cross-linkable vinyl monomer include:
For example, polyfunctional olefins such as butadiene and isoprene,
Polyfunctional acrylates such as diethylene glycol diacrylate, 1,3-butanediol diacrylate, bisphenol A type diacrylate, urethane diacrylate, epoxy diacrylate, trimethylolpropane triacrylate, pentaerythritol tetraacrylate, and phenol novolak type epoxy acrylate; Diethylene glycol dimethacrylate, 1,3-
Polyfunctional methacrylates such as butanediol dimethacrylate, bisphenol A type dimethacrylate, urethane dimethacrylate, epoxy dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetramethacrylate, phenol novolak type epoxy methacrylate, divinylbenzene, bisphenol A type vinyl Polyfunctional vinyl monomers such as benzyl ether, 1,4-phenylenebismaleimide, 4,
Polyfunctional maleimides such as 4'-diphenylmethane bismaleimide, polyfunctional vinyl ethers such as 1,4 cyclohexane dimethanol divinyl ether, 2,2-dimethylhexanediol divinyl ether, diethylene glycol divinyl ether, trimethylolpropane trivinyl ether, divinyl adipate, divinyl Polyfunctional vinyl esters such as phthalate, divinyl isophthalate, divinyl terephthalate, divinyl-1,4-cyclohexanedicarboxylate, cyclohexane dimethanol diallyl ether, 2,2-dimethylhexanediol diallyl ether, diethylene glycol diallyl ether, trimethylolpropanetri Allyl ether, diallyl ether of bisphenol A type, triallyl isocyanurate, di Rirufutareto, diallyl isophthalate, diallyl terephthalate, polyfunctional allyl monomers diallyl esters of phthalic acid polyesters. One of them can be used alone or two or more of them can be used as appropriate.

Among them, polyfunctional olefins such as butadiene and isoprene, 1,4-cyclohexane dimethanol divinyl ether, 2,2-dimethylhexanediol divinyl ether, and diethylene glycol diethylene are preferred because of their excellent copolymerizability with fumaric acid diester. Polyfunctional vinyl ethers such as vinyl ether and trimethylolpropane trivinyl ether; polyfunctional vinyl esters such as divinyl adipate, divinyl phthalate, divinyl isophthalate, divinyl terephthalate, divinyl-1,4-cyclohexanedicarboxylate; cyclohexane dimethanol diallyl ether; , 2-Dimethylhexanediol diallyl ether, diethylene glycol diallyl ether, trimethylolpropane triallyl ether, bisphenol Polyfunctional allyl monomers such as diallyl ether, triallyl isocyanurate, diallyl phthalate, diallyl isophthalate, diallyl terephthalate and diallyl ester of phthalic polyester are exemplified as preferred.

As the polymerization initiator used in the present invention, either a thermal polymerization initiator or a photopolymerization initiator can be used alone, or a combination of a thermal polymerization initiator and a photopolymerization initiator can be used. As the photopolymerization initiator used in the present invention, all conventionally known photopolymerization initiators can be used, and one of them can be used alone or as a mixture of two or more.

Examples of the photopolymerization initiator include benzophenone, xanthone, thioxanthone, acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one and 2-hydroxy-2-methyl-4-isopropylpropio. Examples thereof include phenone, 1-hydroxycyclohexylphenyl ketone, 2,2-diethoxyacetophenone, benzylmethylbenzoyl formate, and benzoin isopropyl ether.

As the thermal polymerization initiator, one or more of an organic peroxide and / or an azo compound can be used. Examples of such a thermal polymerization initiator include benzoyl peroxide, diisopropyl peroxydicarbonate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxyisobutyrate, and tert-butyl peroxy. Pivalate, dicumyl peroxide, tert-butyl cumyl peroxide,
Di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis (tert-butylperoxy) hexyne-3, 2,5-dimethyl-2,5-bis (tert-butyl
Butylperoxy) hexane, α, α'-bis (ter
organic peroxides such as t-butylperoxy) di-m-isopropylbenzene, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 2,2′- Azobis (2,4-dimethylvaleronitrile), 1,1′-azobis (cyclohexane-1-
Azo compounds such as (carbonitrile) and dimethyl 2,2′-azobisisobutyrate.

The content of the fumaric acid diester in the dielectric paint for a film capacitor is preferably 20 to 95 parts by weight, particularly preferably 40 to 80 parts by weight. If the amount of the fumaric acid diester is less than 20 parts by weight, electrical characteristics such as dielectric loss tangent cannot be sufficiently exhibited, while if it is more than 95 parts by weight, adhesion or adhesion to the double-sided metallized film is poor. It tends to be sufficient.

The content of the crosslinked vinyl monomer in the dielectric coating for a film capacitor is preferably 5 to 80 parts by weight, particularly preferably 20 to 60 parts by weight.
When the amount of the cross-linked vinyl monomer is less than 5 parts by weight, the adhesion or adhesion to the double-sided metallized film becomes insufficient. Tends to decrease the mechanical strength.

The content of the polymerization initiator in the dielectric coating for film capacitors is preferably 0.5 to 20 parts by weight, particularly preferably 1 to 10 parts by weight. If the polymerization initiator is less than 0.5 part by weight, the curing becomes insufficient,
When the electrical properties, heat resistance and moisture resistance are reduced, on the other hand, when the content is more than 20 parts by weight, it is difficult to control the curing rate, and at the same time the electrical properties tend to be reduced.

The dielectric coating for a film capacitor of the present invention can be produced by mixing a predetermined amount of a fumaric acid diester, a crosslinked vinyl monomer and a polymerization initiator, followed by heating and dissolving.

At that time, if necessary, an antifoaming agent, a leveling agent, a silane coupling agent, an antioxidant and the like can be further added to the dielectric coating for a film capacitor of the present invention.

The film capacitor element of the present invention comprises:
The dielectric paint for a film capacitor is applied to a metallized film by a coating method such as a microgravure method, a gravure method, or a die coat method, usually in a range of 0.05 to 5 times.
It is obtained by applying a coating having a thickness of 0.1 μm, preferably 0.1 μm to 2 μm, and curing by irradiation with ultraviolet rays or heat treatment to form a dielectric layer. The metallized film is made of polyethylene terephthalate, polyphenylene sulfide, polyethylene naphthalate, or the like used as a base film, and a metal such as aluminum or copper is vapor-deposited on one or both surfaces thereof. Used.

Further, the film capacitor element is provided with one or more layers, preferably 2 to 1, so as to have a predetermined capacitance.
The laminated film capacitor is obtained by laminating 0000 layers, performing interlayer bonding in a heat press process, and cutting. By spraying metallikon as an external electrode onto the film capacitor element or the laminated film capacitor as an external electrode, welding a lead wire thereto, and covering the same, a commercial film capacitor element or a laminated film capacitor can be obtained. The element for a film capacitor or the laminated film capacitor of the present invention obtained by the above method has a dielectric loss tangent (tan δ) of 0.00.
It has a performance of 4 or less and has good electrical characteristics.

[0020]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. The abbreviations and compound names are shown for the fumaric acid diester, crosslinked vinyl monomer and polymerization initiator used in the examples. DiPF: diisopropyl fumarate DtBF: di-tert-butyl fumarate DcHF: dicyclohexyl fumarate BD: butadiene DVB: divinyl benzene CHDVE: 1,4-cyclohexane dimethanol divinyl ether HDVE: n-hexanediol divinyl ether DMHDVE: 2.5 -Dimethyl-2,5-hexanediol divinyl ether BDDA: 1,4-butanediol diacrylate BPDA: bisphenol A type diacrylate of the following formula (2)

[0021]

Embedded image

(Where φ is a benzene nucleus) TMPTMA: trimethylolpropane trimethacrylate PhDMI: 1,4-phenylenebismaleimide TMPTAE: trimethylolpropane triallyl ether DATP: diallyl terephthalate PDAIP: Formula (3) below Polyester of Phthalic Acid Polyester

[0023]

Embedded image

Wherein φ is a benzene nucleus and m is 0 to
5 ) HMPP: 2-hydroxy-2-methyl-1-phenylpropan-1-one DDPE: 2,2-dimethoxy-1,2-diphenylethan-1-one BPO: benzoyl peroxide AIBN: azobisisobutyronitrile

Examples 1 to 12 Dielectric coatings for film capacitors were prepared according to the compositions shown in Table 1. The obtained dielectric paint for a film capacitor is a film on which aluminum is vapor-deposited (using polyethylene terephthalate having a length of 100 m, a width of 120 mm and a thickness of 3.5 μm, and a length of 100 m, a width of 4.5 mm, and a thickness of several hundred angstroms on both sides) Is formed in stripes at intervals of 0.5 mm in the width direction.) To a thickness of 1 μm using a microgravure coater. Next, in a state where the concentration of oxygen in the ultraviolet irradiation portion was 1% or less, ultraviolet light having an intensity of 10 mJ / cm ² was irradiated and cured. Further, the other side was coated, irradiated with ultraviolet rays, and cured in the same manner to obtain an element for a film capacitor. Next, 10 pieces of the above-mentioned film capacitor elements are laminated, the interlayer bonding is performed in a heat press process, and after cutting, a metallikon is thermally sprayed as an external electrode, a lead wire is welded thereto, and a package is formed. Produced. Then, with the following test method, withstand voltage,
The insulation resistance, capacitance, dielectric loss tangent (tan δ), solder heat resistance, high temperature load test, moisture resistance test, and solvent resistance were determined, and the results are shown in Tables 2 and 3.

<Dielectric Strength> The dielectric strength was measured by a method according to JISC5120. <Insulation resistance> The insulation resistance was measured by a method based on JISC5120. <Capacitance> The capacitance was measured by a method based on JISC5120. <Dielectric loss tangent> The dielectric loss tangent was measured by a method based on JISC5120. <Solder heat resistance> 260 ° C solder bath (TAIYO EL
CTRIC IND. CO, LTD POT-200
C) was immersed for 120 seconds, and before and after the test, な け れ ば was given if there was no change in electrical performance and electrical performance relating to withstand voltage, insulation resistance, capacitance and dielectric loss tangent, and × was given if there was change.

<High temperature load test> The high temperature load test was performed according to JISC.
The measurement was performed by a method in accordance with 5120, and before and after the test, 性能 was given if there was no change in the electric performance and appearance regarding withstand voltage, insulation resistance, capacitance and dielectric loss tangent, and × was given if there was a change. <Moisture resistance load test> A moisture resistance load test was measured by a method in accordance with JISC5120, and before and after the test, the withstand voltage, insulation resistance,
If there was no change in the electrical performance and appearance regarding the capacitance and the dielectric loss tangent, it was evaluated as ○, and when there was a change, it was evaluated as ×. <Solvent resistance> It was immersed in toluene and methylene chloride according to JIS C6481, and its appearance was evaluated. ○ if there is no change in shape such as swelling and roughness, × if there is change
And

[0028]

[Table 1]

[0029]

[Table 2]

[0030]

[Table 3]

Comparative Example 1 Polycarbonate was dissolved in a mixed solvent of dichloromethane and 1,2-dichloroethane (weight ratio: 1: 1), and 6 w
The same procedure as in Example 1 was carried out except that a solution of t% was coated and dried on the same aluminum-deposited film as in Examples 1 to 12 so as to have a dry film thickness of 1 μm to obtain a film capacitor element. The withstand voltage, insulation resistance, capacitance, dielectric loss tangent (tan δ), solder heat resistance, high temperature load test, moisture resistance load test, and solvent resistance were determined, and the results are shown in Tables 2 and 3.

In the multilayer film capacitors obtained in Examples 1 to 12, the capacitance was 0.1 to 1.0 μF.
And the dielectric loss tangent (tan δ) at 1 KHz is 0.1.
002-0.004, the insulation resistance was 1 × 10 ⁶ Mohm (described in the table as MΩ) or more at 0.01 μF, and the withstand voltage of the sheet was 450 V / μm on average.
This is a result that the withstand voltage, the insulation resistance, the capacitance, and the dielectric loss tangent are improved as compared with the related art, and the solder heat resistance, the high temperature load test, the humidity load test, and the solvent resistance are excellent.

[0033]

The film capacitor element and the laminated film capacitor of the present invention are excellent in electrical properties such as capacitance and dielectric loss tangent, heat resistance, moisture resistance and solvent resistance. Further, the dielectric paint for a film capacitor does not use a solvent, so that it consumes little resource energy and is excellent in terms of environment and cost. These things are of great industrial value.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01G 4/18 H01G 4/20 4/30 301 4/24 321C 331A

Claims (4)

[Claims] 1. A dielectric paint for a film capacitor comprising a fumaric acid diester, a vinyl monomer having at least two carbon-carbon double bonds in one molecule, and a polymerization initiator. 2. A dielectric for a film capacitor obtained by curing the dielectric coating for a film capacitor according to claim 1. 3. An element for a film capacitor, comprising the dielectric layer for a film capacitor according to claim 2 formed on at least one surface of a metallized film. 4. A laminated film capacitor obtained by laminating the film capacitor element according to claim 3.