JPH0458122B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a capacitor impregnated with an improved electrical insulating oil. Conventionally, animal and vegetable oils such as polybutene, alkylbenzene, phthalate esters, and castor oil have been widely used as electrical insulating oils because of their low cost. One form of use of these electrical insulating oils is as electrical insulating oil for impregnating oil-impregnated electrical equipment such as oil-impregnated capacitors and oil-impregnated cables. Incidentally, in recent years, demands have increased for oil-impregnated electrical equipment such as oil-impregnated capacitors, oil-impregnated cables, and transformers for higher voltage, longer life, and smaller size, and along with this, improvements have been made in terms of insulating and dielectric materials. It was planned. In other words, from the perspective of insulating materials and dielectric materials,
Polypropylene, polyolefins such as polymethylpentene, polyester, polyvinylidene fluoride resin, which have superior dielectric strength than conventional insulating paper,
Plastic materials such as polycarbonate are used. For example, in an oil-impregnated capacitor, these plastic films may be used in combination with insulating paper, or these plastic films may be used alone. Capacitors using metallized paper or metallized plastic film, in which the electrodes are metal layers deposited on the paper or plastic film, have also been used. In addition, in oil-impregnated cables, instead of insulating paper, crosslinked or uncrosslinked polyethylene, stretched or unstretched polypropylene, polyolefins such as polymethylpentene, polyester, polyvinylidene fluoride resin, polycarbonate, and other plastic films are used as insulators. Single films or composite films of these plastic films and insulating paper have been developed. Examples of this composite film include a film in which plastic is laminated on insulating paper by melt extrusion or thermocompression bonding, a composite film in which insulating paper and silane-grafted polyethylene are cross-linked in the presence of a silanol condensation catalyst, or There are mixed papers made from paper pulp and plastic fibers such as polyolefin. Therefore, there is a demand for improvement in the performance of the electrical insulating oil and the like. In view of the above-mentioned circumstances, the present inventors conducted extensive research and found that by mixing an aromatic olefin having two condensed or non-condensed aromatic rings with the electrical insulating oil, metallized paper or metal It has been discovered that an electrical insulating oil particularly suitable for use in capacitors using recycled plastic film can be obtained, and the capacitor of the present invention has been completed. That is, the present invention provides (a) one or more electrical insulating oils other than polycyclic aromatic hydrocarbons, and (b)
At least two fused or non-fused aromatic rings
One or more ring-containing aromatic olefins
This invention relates to a capacitor using metallized paper or film impregnated with electrical insulating oil of 0.01 to 50% by weight (based on the total amount of a and b). The electrical insulating oil in item (a), which is one component of the electrical insulating oil used in the capacitor of the present invention, is a conventionally known electrical insulating oil other than polycyclic aromatic hydrocarbons. Here, the polycyclic aromatic hydrocarbon is an aromatic hydrocarbon containing at least two types of fused or non-fused aromatic rings, such as diarylalkane (or cycloalkane) such as phenylxylylethane. ), alkyl (or cycloalkyl) biphenyl, such as monoisopropyl biphenyl,
Alkyl (or cycloalkyl) naphthalenes such as diisopropylnaphthalene, triarylalkane, terphenyl, aryl (or aralkyl) naphthalene, and the like. Therefore, the electrical insulating oil in item (a) specifically refers to alkyl (or cycloalkyl)benzenes such as dodecylbenzene, monocyclic aromatic hydrocarbons such as alkylindanes, polybutene, poly(α - olefin oligomers such as olefin);
It is a mixture of one or more of phthalic acid esters such as dioctyl phthalate, animal and vegetable oils such as castor oil, mineral oil, and silicone oil. The compound used in combination with the electrical insulating oil in item (a) above is (b)
It is an olefin having two fused or non-fused aromatic rings. These olefins include cyclic olefin derivatives such as cyclopentene and cyclohexene, and chain olefin derivatives. Examples of such olefins include compounds represented by the following general formulas () to (). general formula Here, R ₁ is an alkenylene group or a cycloalkenylene group having one unsaturated double bond. Further, m and n are integers from 0 to 3, m R ₂ and n R ₃ are the same or different, and are hydrogen atoms or alkyl groups. general formula Here, R ₄ is an alkenyl group or a cycloalkenyl group, and R ₅ is an alkylene group or a cycloalkylene group. Further, m and n are integers from 0 to 3, m R ₂ and n R ₃ are the same or different, and are hydrogen atoms or alkyl groups. general formula Here, R ₄ is an alkenyl group or a cycloalkenyl group. Further, m and n are integers from 0 to 3, m R ₂ and n R ₃ are the same or different, and are hydrogen atoms or alkyl groups. general formula Here, R ₄ is an alkenyl group or a cycloalkenyl group. Further, m and n are integers from 0 to 3, m R ₂ and n R ₃ are the same or different, and are hydrogen atoms or alkyl groups. The alkenylene group or cycloalkenylene group of R ₁ in the above formula () is 2 from ethylene, propylene, butene, isobutene, pentene, methylpentene, hexene, cyclopentene, cyclohexene, alkylcyclohexene, etc.
It is a divalent substituent excluding hydrogen atoms, and the alkyl groups R ₂ and R ₃ are methyl, ethyl,
These include propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl and amyl groups. Specific compounds of formula () include stilbene, 4-methylstilbene, 1,2-diphenylpropene, 1,3-diphenylpropene, 1,4
-diphenylbutene-1, 1,4-diphenylbutene-2, 1,1-diphenylethylene, 1-phenyl-1-(4-ethylphenyl)ethylene,
1,1-diphenylpropene-1,2,3-diphenylpropene, 1,2-diphenylbutene-
Examples include 2,1,3-diphenylbutene-1, 2,4-diphenyl-4-methylpentene-1, 1,2-diphenylcyclohexene, and phenylbenzylcyclohexene. These can be produced by acid-catalyzed dimerization or co-dimerization of styrene or styrenes such as α-methylstyrene and vinyltoluene. Furthermore, 1,2-diphenylethylene and the like may be dehydrated by reacting benzaldehyde with benzylmagnesium bromide, and the same can be applied to 1,2-diphenylpropene. Furthermore, 1,1-diphenylethylene can be obtained by reacting diphenyl ketone with a Grignard reagent such as methylmagnesium iodide and dehydrating it. R ₄ in the compound of formula () is vinyl, propenyl, isopropenyl, allyl, butenyl,
It is an alkenyl group or cycloalkenyl group such as cyclopentenyl and cyclohexenyl, and R ₅
is a divalent substituent obtained by removing two hydrogen atoms from a chain saturated aliphatic hydrocarbon or a saturated alicyclic hydrocarbon such as cyclopentane, cyclohexane, and cycloheptane. Further, R ₂ and R ₃ which are alkyl groups are the same as R ₂ and R ₃ in formula (). Specific compounds of formula () include 1-phenyl-1-(4-vinylphenyl)ethane, 1-
(4-methylphenyl-1-(4-vinylphenyl)ethane, 1-phenyl-1-(4-isopropenylphenyl)ethane, phenyl-(4-vinylphenyl)methane, phenyl-(cyclohexenylphenyl)methane, etc. These can be synthesized by various synthetic chemical methods.For example, phenyl-(vinylphenyl)ethane is produced by reacting diphenylethane with acetyl chloride using a Friedel-Crafts catalyst to obtain phenyl-(acetylphenyl)ethane. , and then reduced with sodium borohydride etc. and then dehydrated. Phenyl-(isopropenyl phenyl) ethane etc. are obtained by reacting phenyl-(formylphenyl) ethane with a Grignard reagent such as methylmagnesium iodide, and then It can be obtained by dehydration. In addition, R ₄ which is an alkenyl group or a cycloalkenyl group in formula () is the same as R 4 in formula (), and R ₄ as an alkyl group
R ₂ and R ₃ are also the same as R ₂ and R ₃ in formula (). Specific compounds of the formula () include 2-isopropenylbiphenyl, 4-isopropenylbiphenyl, 2-isopropenyl-4'-isopropylbiphenyl, cyclohexenylbiphenyl, and cyclopentenylbiphenyl. Among these, for example, isopropenyl biphenyl is
It can be obtained by dehydrogenation of isopropyl biphenyl. Furthermore, R ₄ as an alkenyl group or a cycloalkenyl group in formula () is also the same as R ₄ in formula (), and R ₂ and R ₃ as an alkyl group are also the same as R 2 and R ₃ in formula ().
Same as _R3 . Specific compounds of this formula () include α-vinylnaphthalene, isopropenylnaphthalene, allylnaphthalene, and 1-cyclopent-2-enylnaphthalene. Among these, for example, vinylnaphthalene can be obtained by reacting formylnaphthalene with a Grignard reagent such as methylmagnesium iodide and then dehydrating it. The aromatic olefin in item (b) is used by mixing and dissolving it with the electrical insulating oil in item (a), and it is sufficient if it becomes liquid at room temperature after mixing and dissolving. Therefore, as long as they are compatible with each other without separation or precipitation after mixing and dissolution, they may be either liquid or solid at room temperature. Further, this olefin having two fused or non-fused aromatic rings can be used alone or in combination with the electrical insulating oil in item (a) above as a mixture of two or more. The mixing ratio of the electrical insulating oil in item (a) above and the aromatic olefin in item (b) is arbitrary, but the latter aromatic olefin should be in the range of 0.01 to 50% by weight relative to the total amount of both. This is preferable from the viewpoint of synergistic effects. Moreover, the range is more preferably 1.0 to 30% by weight. In addition, antioxidants known as electrical insulating oils,
For example, as a phenolic type, 2,6-di-tert-butyl-p-cresol (trade name: BHT),
2,2'-methylenebis(4-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3
-methyl-6-tert-butylphenol), 4,
4'-thiobis(3-methyl-6-tert-butylphenol), stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenol)propionate (trade name: Irganox 1076), tetrakis[methylene- 3(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane- (trade name: Irganox 1010), 1,3,5-trimethyl-
2,4,6-tris(3,5-di-tert-butyl-
4-Hydroxybenzyl)benzene (Product name:
Ionox 330), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenol)
butane (product name: TopanolCA), sulfur-based compounds include dilaurylthiodipropionate, distearylthiodipropionate, laurylstearylthiodipropionate, dimyristylthiodipropionate, and phosphorus-based compounds such as triisopropionate. Decyl phosphite, diphenylisodecyl phosphite, triphenyl phosphite, trinonylphenyl phosphite and the like can be added to the electrical insulating oil used in the capacitor of the present invention. These antioxidants can be used individually or in a mixture of two or more, and the amount added is 0.001 to 0.01 to insulating oil.
5% by weight, more preferably 0.01-2.0% by weight. Furthermore, known epoxy compounds may be used in combination as additives for electrical insulating oil. The electrical insulating oil used in the capacitor of the present invention is
In addition to being generally suitable as electrical insulating oils, it is also preferred for impregnating oil-impregnated electrical equipment such as capacitors, cables and transformers, especially capacitors using metallized paper or plastic films. Note that the structures of these devices are as already described. That is, by impregnating a capacitor made of metallized paper or plastic film with the electrical insulating oil as described above, it is possible to increase the pressure, downsize, and extend the life of the oil-impregnated capacitor. Therefore, it is possible to improve the performance of the electrical insulating oil described in item (a) above, which is generally considered to be inexpensive but has relatively poor performance, and by using the mixture, an excellent capacitor can be obtained. This has great industrial value. Furthermore, by impregnating an insulating oil consisting of multiple components, as a result of the synergistic effect between the components,
It improves the above properties, maintains the excellent electrical properties, biodegradability, heat resistance, and oxidation stability of each component itself, and adjusts the viscosity and pour point to a suitable range. Therefore, the oil-impregnated capacitor can be manufactured efficiently and easily, and the oil-impregnated capacitor that exhibits high performance can be obtained without restrictions due to usage conditions. Next, the present invention will be explained in more detail using Examples and Comparative Examples. Examples and Comparative Examples Various insulating oils (Nos. 1 to 11) were prepared by mixing aromatic olefins with various electrical insulating oils as shown in Table 1. Among these, insulating oil No.
Nos. 1, 5, 8 and 10 are comparative examples, and the others are examples. For insulating oil No. 1 to 11, thickness is 14μ, width is 41
Capacitors were fabricated using single-sided metalized paper with a length of 9.6 mm and a length of 9.6 m as electrodes and dielectrics, and impregnated with the respective insulating oils. Capacity is No. 1 insulating oil
It is 2.5μF for a capacitor impregnated with ~7,
The capacitance of the capacitor impregnated with insulating oil Nos. 8 to 11 was 2.8 μF. A voltage of 500V was applied to these capacitors for 100 hours, and the rate of decrease in capacitance and rate of increase in dielectric loss tangent before and after the voltage was applied was investigated. The results are shown in Table 1. As a comparative example, phenylxylylethane (insulating oil No. 12), which is a polycyclic aromatic hydrocarbon, and a case in which aromatic olefin was added to this (insulating oil No. 12) were used.
13) was also tested. The single-sided metallized paper used, its dimensions, and the method for manufacturing the capacitors were the same as those for insulating oil Nos. 1 to 11, and the capacitance of the capacitor impregnated with the insulating oil was 2.5 μF.
The same tests as above were conducted on them. The results are also shown in Table 1. Comprehensive consideration of the results in Table 1 shows that in the present invention (insulating oil Nos. 2 to 4, 6, 7, 9, and 11),
Comparative examples (insulating oil No. 1, 5, 8 and
10) from one-fifth to one-twentieth of the value. On the other hand, in the case of phenylxylylethane alone (insulating oil No. 12), which is a polycyclic aromatic hydrocarbon, although its properties as an insulating oil are originally good,
-When adding diphenylbutene-1 (insulating oil
The capacity reduction rate of No. 13) was about half the value, and the effect of addition was low. Furthermore, regarding the rate of increase in dielectric loss tangent, the value of the present invention (insulating oil Nos. 2 to 4, 6, 7, 9, and 11) is about 2 that of the comparative example (insulating oil Nos. 1, 5, 8, and 10). It is 1/1. In the case of phenylxylylethane, even if aromatic olefin is added (insulating oil No. 13), the rate of increase in the dielectric loss tangent is only slightly lowered. That is, polycyclic aromatic hydrocarbons such as phenylxylylethane have a high unit price and do not meet the objective of providing a capacitor impregnated with an electrical insulating oil that is inexpensive and has good characteristics according to the present invention.

【table】

[Table] Next, the changes in breakdown voltage when 1,1-diphenylethylene was added as an aromatic olefin to various electrical insulating oils were compared for capacitors using metallized films and foil-wound capacitors. (Preparation of capacitor) An oil-impregnated model capacitor was prepared by winding two polypropylene stretched films with a thickness of 14 μm and a width of 14 mm as a dielectric material together with aluminum foil as an electrode according to a conventional method. This foil-wound capacitor is called capacitor A. Next, a metalized polypropylene stretched film with a width of 40 mm and a margin of 3 mm, on which aluminum was vapor-deposited as an electrode on one side, was wound together with other polypropylene films to prepare an oil-impregnated model capacitor. This metallized film capacitor will be referred to as capacitor B. By impregnating the capacitors A and B with the insulating oil shown in Table 2 under vacuum according to a conventional method, capacitors each having a capacitance of about 5 μF were obtained. (Test of capacitor) AC voltage was applied to each of capacitors A and B, the voltage was increased, and the voltage at which the capacitor was destroyed was measured. In addition, each of the seven capacitors was measured by impregnating them with the same insulating oil, and the value obtained from the average value of the voltage at breakdown of the remaining five capacitors after excluding the maximum and minimum values was calculated. It was taken as the breakdown voltage of the capacitor. Table 2 shows the results.
It is also shown in . As can be seen from the table, all capacitors B using metallized films exhibit higher breakdown voltages than those using only the base insulating oil. In other words, the effect of improving the characteristics of the base insulating oil is greater than in the case of a foil-wound capacitor. Therefore, the present invention exhibits excellent effects in capacitors using metallized films.

【table】

【table】

Claims (1)

[Scope of Claims] 1 (a) one or more electrical insulating oils other than polycyclic aromatic hydrocarbons, and (b) an aromatic olefin having at least two fused or non-fused aromatic rings. 1 or 2 of
A capacitor using metallized paper or film impregnated with an electrical insulating oil consisting of 0.01 to 50% by weight (based on the total amount of a and b) of at least 0.01% to 50% by weight (based on the total amount of a and b). 2. A capacitor using metallized paper or film according to claim 1, wherein the insulating oil contains 0.001 to 5% by weight of an antioxidant.