JPS5975502A - New electrically insulating oil - 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 a new electrical insulating oil comprising an alkylbiphenyl and an aromatic bicyclic olefin. For more details,
Oil-impregnated electrical equipment having a metal conductor or metal electrode and an insulator or dielectric made of a plastic material such as polyolefin applied to at least a part thereof, such as oil-impregnated capacitors, oil-impregnated cables, etc. The present invention relates to a new electrical insulating oil composed of an alkyl biphenyl and an aromatic binary olefin, which is suitable for the following cases.

In recent years, as oil-impregnated electrical equipment such as oil-impregnated capacitors, oil-impregnated couples, and transformers have become higher in voltage, longer in life, and smaller in size, various plastic materials, F-1, have come to be used together with conventional insulating paper. Ta.

These plastic materials Id1 used as constituent materials of oil-impregnated electrical equipment are likely to be used more and more in the future, and products in which all conventional insulating paper is replaced with plastic materials have already begun to be used.

However, conventional electrical insulating oils, such as refined mineral oil, polybutene, alkylbenzene, chlorinated biphenyls, etc., have various drawbacks. For example, chlorinated biphenyls are avoided due to pollution problems. Further, various conventional electrical insulating oils do not necessarily have satisfactory compatibility with 70-last ink materials such as polyolefins used in the oil-impregnated electrical equipment. In other words, conventional electrical insulating oil is
Contact with F can melt or swell the plastic material, reducing its dielectric strength. Therefore, there has been a strong need for a high-performance electrical insulating oil that can better meet the demands for higher voltage and smaller size of oil-impregnated electrical equipment.

The present inventors conducted extensive research in view of the above circumstances, and found that by blending an aromatic binary olefin with alkylbiphenyl, an electrical insulating oil with significantly superior properties could be obtained. It is completely completed.

In other words, the present invention provides an electrolyte comprising (a) one or more alkylbiphenyls, and (b) one or more olefins having two fused or non-fused aromatic rings. This relates to insulating oil.

The alkyl group in the alkyl biphenyl in the above (,) is a methyl group, ethyl group, propyl group, inkyl group, n-butyl group, 5ec-butyl group, j;ert-butyl group, inobutyl group, amyl group, etc. The total number of carbon atoms in the alkyl group is 1, although there may be more than one.
~10 pieces are preferred. In addition, these alkylbiphenyls can be used alone or as a mixture of two or more, and their viscosity at 4.00C is 1.
OcSt or less are suitable for use as a component of the electrical insulating oil of the present invention. Particularly preferred is monoisopropylbiphenyl.

The above alkylbiphenyl can be produced by a high-temperature radical reaction of benzene, or by an alkylbiphenyl reaction between benzene and chlorobenzene.
biphenyl obtained from Nyong.

It can be obtained by converting olefins such as ethylene and 7° propylene, and chloroethane and chloropropane natonohaloke octaminated hydrocarbons into alkynes.

The compound used in combination with the alkyl biphenyl in the above (,) is the omfin having two fused or non-fused aromatic rings as in the (b). There are derivatives of cyclic olefins such as olefins, cyclopentene, and cyclohexene, and chain olefin derivatives.For example, such olefins include compounds represented by the following general formulas (1) and 2). There is.

General formula % Formula % (1) Here, R□ is an alkenylene group or a cycloalkenylene group having one unsaturated double bond. 1.
Furthermore, m and n are integers from O to 3, m R2s and n R3s are each the same or different, and are a hydrogen atom or an alkyl group.

General formula % Formula % () Here, R4 is an alkenyl group or a cycloalkenyl group, and R5 is an alkylene group, 1r:i, or cycloalkylene group. In addition, m and n are integers of O~3, m R2s and n R3s are the same or different, and they are hydrogen atoms -! or an alkyl group.

General formula %) Here, R4 is an alkenyl group or a nochloroalkenyl group, and m and 1) are integers from 0 to 3, and m R2 and n R3 are 1 are the same or different, and d hydrogen atom -1:/ is an alkyl group.

In the general formula, R4 is an alkenyl group or a cycloalkenyl group. Further, m and n are integers of 0 to 3, and m R2 and n R3 are respectively the same or different,
They are hydrogen atoms or alkyl groups.

``Two sets of formula <I) Alkenylene group or cycloalkenylene group of R□ in K, ethylene, fluoropyrene, phthene, isobutyne, intene, methylintene, hexene, cyclopentene, cyclohexene 1ftld alkylcyclohexe/, etc. It is a divalent substituent excluding a hydrogen atom, and the alkyl group and R3 are alkyl groups such as methyl, ethyl, zorobyl, isozorobyl, butyl, isobutyl, sec-butyl, tert-butyl, and amyl.

Specific compounds of formula (I) include stilbene, 4-methylstilbene, 1,2-nophenylgloben,
, 3-diphenylzolopene, 1,4-nophenylbutene-1,1,4-nophenylguten-2,1,1-nophenylethylene, 1-phenyl-1-(4-ethylphenyl)ethylene, 1.1 -nophenylprozene-1,2,
3-nophenylzoloben, 1,2-nophenylbutene-2, Phenyl-bennol/chlorhexenate.

These are acid catalysts of styrene or styrenes such as α-methylstyrene and vinyltoluene. It can be produced by trimerization or co-dimerization by Te. Also, ■
, 2-diphenylethylene, etc. can be completely reacted with benzaldehyde and pennormagneum bromide, and then dehydrated. It is obtained by completely reacting nophenyl ketone with a Grignard reagent such as methylmagnenium iodide and then dehydrating it.

In the compound of formula (II), R4 is an alkenyl group or a cycloalkenyl group such as vinyl, propenyl, isoflobenyl, allyl, butenyl, cyclobentenyl, cyclohexenyl, and R5 is a linear saturated aliphatic hydrocarbon or cyclointanyl group. It is a divalent substituent obtained by removing two hydrogen atoms from a saturated alicyclic hydrocarbon such as , nclohexane, and nclohezotane.Also, the definition of R2 and R3, which are alkyl groups, is the same as R2 and R3 in 4). It is.

Specific compounds of formula (n) include 1-phenyl-1-
(4-vinylphenyl)ethane, 1-(4-methylphenyl)-1-(4-L”nylphenyl)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 can be obtained by subjecting diphenylethane to a complete reaction with acetyl chloride using a Friedel-Krach catalyst to obtain phenyl (acetylphenyl) ethane. It is then reduced with sodium borohydride or the like and then dehydrated. phenylisopronylphenyl)ethane-1, and phenyl-(
Formylphenyl)ethane can be obtained by reacting with a Grignard reagent such as methylmagnesium iodide, followed by dehydration.

However, R4, which is an alkenyl group or a cycloalkenyl group in formula (1), is the same as R4 in formula (11), and R2 and R3, which are alkyl groups, are also
) is the same as the face and R3.

Specific compounds of formula (III) include 2-isopronylbiphenyl, 4-(:/7'-ropyrubiphenyl, 2-isoprobenyl-4'-(rough-0-ropyrubiphenyl, cyclohexenylbiphenyl, cyclohexenylbiphenyl). There are pentenyl piphenyl, etc. Among these, toeha and impropenyl biphenyl can be obtained by dehydrogenation of ino-70 lopyru biphenyl.

Furthermore, R4 as an alkenyl group or a cycloalkenyl group in formula (IV) is also the same as R4 in formula (II), and R2 and R3 as an alkyl group are also the same as R2 and R3 in formula (If). .

Specific examples of the compound of formula (IV) include α-vinylnaphthalene, nylnaphthalene, allylnaphthalene, and 1-cycloiso)-2-enylnaphthalene. Among these, for example, bi,=lunaphthalene can be obtained by reacting formylnaphthalene with a Grignard reagent such as methylmagnesium iodide, followed by dehydration.

The aromatic olefins represented by formulas (I) to (IV) are used by being mixed and dissolved with alkylbiphenyl, and it is sufficient that they become liquid at room temperature after being mixed and dissolved. Therefore, it may be either liquid or solid at room temperature. Further, an olefin having all two aromatic rings, fused or non-fused, can be used alone or in combination with alkyl biphenyl as a mixture of two or more types.

In the present invention, an electrical insulating oil is obtained by mixing the aromatic olefin (b) with the alkylbiphenyl (,) as described above, but the viscosity of the insulating oil thus obtained is It is preferably 30 cst or less at 40°C, more preferably 10 cst. Therefore, the compounds represented by formulas (1) to (IV) above are appropriately selected and used as the alkyl biphenyl (a) and the aromatic olefin (b) so that the viscosity after mixing falls within this range. Good.

Alkylbiphenyl itself has excellent electrical properties as well as biodegradability, heat resistance, and oxidation stability, and is also excellent in hydrogen gas absorption, but when used together with the aromatic olefin of the present invention, hydrogen gas absorption Even though unsaturated compounds such as aromatic olefins are used in combination, no decrease in biodegradability, thermal stability, or oxidative stability was observed, and other electrical properties were improved. Go further.

The mixing ratio of the alkyl biphenyl (a) and the aromatic olefin (b) is arbitrary, but the latter aromatic olefin can be in the range of 0.01 to 50% by weight based on the total amount of both. This is good from the point of view of synergistic effects. More preferably, it is in the range of 1.0 to 30% by weight.

The electrical insulating oil of the present invention consists of a mixture having the above composition, but is not limited thereto. That is, conventionally known electrical insulating oils such as polybutene, mineral oil, alkylbenzene, alkylnaphthalene, noaryl alkane, etc. are added for the purpose of completely improving the desired electrical performance within a range that does not impair the general electrical performance. can be used.

Generally, adding polybutene improves volume resistivity and dielectric loss tangent, mineral oil improves dielectric breakdown voltage, and other aromatic insulating oils such as alkylbenzene improve dielectric breakdown voltage, dielectric loss tangent, pour point, etc. There is a tendency to improve.

Additionally, known antioxidants such as phenolic antioxidants such as 2,6-no-tert-butyl-p-cresol (trade name BHT), 2,2'-methylenebis (4-methyl-6-tert-butyl-p-cresol), tributylphenol), 4.4'
-butylidenebis(3-methyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6=tert-butylphenol), stearyl-β-(3,5-no-tert-butyl-4-hydroxy phenol) norobionate (trade name Irganox 1076), tetrakis[methylene-3(3',5'-no-tert-butyl-4'-hydroxyphenyl)zolopionate]methane (trade name Tr
ganox 1010), 1.3.5-trimethyl-
2,4,6-tris(3,5-no-tertiary dithyl-4-hydroxypennol)benzene (trade name Ionox 33
0), 1,1. :3-) Lis(2-methyl-4-hydroxy-5-tert-butylphenol)butane (trade name T
dilauryl thiodipropionate, nostearyl thiodizolopionate, lauryl stearyl thiodipropionate,
Dimyristylthionozoropionate, etc., and phosphorus compounds such as triisodecyl phosphite, nophenylinodenorphosphite, triphenyl phosphite, and trinonylphenyl phosphite are used by adding them to the electrical insulating oil of the present invention. be able to. 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 to 2.0% by weight.

Further, phosphoric acid ester compounds, epoxy compounds, and the like, which are known as additives for electrical insulating oils, may be used in combination for the purpose of imparting flame retardancy and other purposes.

The electrical insulating oil of the present invention is suitable as a general electrical insulating oil, and is particularly suitable for impregnating oil-impregnated electrical equipment such as capacitors, cables, and transformers.

As mentioned above, in recent years there has been a strong demand for higher voltage and smaller size for these oil-impregnated electrical equipment, and as a result, instead of the conventional insulating paper, Alternatively, glasstic has come to be used in combination with insulating paper. Specifically, in capacitors, a combination of stretched or unstretched plastic film such as polypropylene, polymethylpentene, or polyester and insulating paper is used as the insulator (dielectric material) of the capacitor, or a glass film of these materials is used. There are those using only a film, and furthermore, there are plastic films that are finely embossed to make them easier to impregnate, and metallized plastic films that have a metal layer on the entire surface as electrodes. =! As an insulator for OF cables (OF cables), crosslinked or uncrosslinked polyethylene, stretched or unstretched polypropylene, polymethylene fin films such as polymethylene, silane, etc. are used instead of insulating paper, and insulating paper and A laminated film laminated with a polyolefin by km melt extrusion, a composite film made by cross-linking insulating paper and silane-grafted polyethylene in the presence of a ranol condensation catalyst, or a mixture of paper/alcohol and polyolefin fibers. There is paper making, etc.

The electrical insulating oil of the present invention also has excellent compatibility with plastics, so it can be used in oil-impregnated electrical equipment using plastic as part or all of its insulators or dielectrics, as described above. Suitable for impregnating capacitors, cables, etc.

i.e. plastics, especially polyolefins, all-insulators (
For capacitors used in part or all of dielectric materials,
When impregnated with the electrical insulating oil of the present invention, the swelling of the plastic insulator is small, so that the electrical insulating oil is sufficiently impregnated and no voids (unimpregnated portions) are formed. Therefore, there is a risk that corona discharge will occur due to electric field concentration in the void, leading to dielectric breakdown. In addition, the electrical insulating oil of the present invention has excellent hydrogen gas absorption properties and corona discharge resistance under high voltage, and has a long life. High-pressure cultivation can be achieved.

Similarly, in the case of cables, the dimensional change of the insulation due to swelling is small, so the oil flow resistance of the insulating oil is extremely low.
When impregnating the cable with oil, the impregnation time for insulating oil is shortened. Of course, since impregnation is easily performed, voids are less likely to occur, resulting in a higher dielectric breakdown voltage. In addition, cables using an insulator made of a laminated film of plastic film and insulating paper or a composite film may suffer from delamination, peeling due to bending, wrinkles, and buckling even if they come into contact with the insulating oil of the present invention for a long period of time. There is little risk that such things will occur. Furthermore, since insulating oil has excellent hydrogen gas absorption properties, it is possible to obtain a cable with excellent corona discharge resistance similar to that of a capacitor. Therefore, a cable with a long life and high voltage can be obtained like a capacitor.

Furthermore, by impregnating an insulating oil consisting of multiple components, the above-mentioned mechanical properties are improved as a result of the synergistic effect between the components, and each component itself has excellent electrical properties, biodegradability, heat resistance, etc. In addition to maintaining oxidation stability, the viscosity and pour point can be adjusted to a suitable range, making it possible to manufacture oil-impregnated electrical equipment efficiently and easily, and exhibiting high performance without restrictions due to usage conditions. It is possible to obtain oil-impregnated electrical equipment.

Next, the present invention will be explained in detail with reference to Examples and Comparative Examples.

Examples and Comparative Examples The insulating oils used in these Examples and Comparative Examples are summarized in Table IK. In Table 1, insulating oil N111.19.20.21 is used as a comparative example.

In each test, 0.2 parts by weight of BHT was added as an antioxidant to the insulating oil.

The viscosity of any strained insulating oil is 4.5-6.
It was 5 cst.

(1) Compatibility with polyzolopylene film After immersing a polypropylene film (thickness 14μ) cut into a predetermined shape in various insulating oils at 80°C for 72 hours, the film completely collapsed, and the volume of the film before and after immersion All rates of change (related) were measured.

The results are shown in Table 2, and it can be said that the smaller the value, that is, the smaller the volume change rate, the less the film swells, the better the dimensional stability, and the better the compatibility with the polypropylene film.

As can be seen from the results shown in Table 2, all of the insulating oils of the present invention have good compatibility with polypropylene. on the other hand,
It is clear that insulating oils 19 and 20 containing aliphatic olefins such as 1-hexadecene and 1-decene have large volume changes and are not compatible with polypropylene.

(2) A polypropylene film with a thickness of 14μ was used as a test dielectric for oil-impregnated capacitors.
An oil-impregnated model capacitor was fabricated by using a stack of aluminum foils as electrodes and winding and laminating them according to a conventional method.

This capacitor is impregnated with various insulating oils under vacuum.
An oil-impregnated capacitor with a capacitance of about 0.4 μF was fabricated.

Next, voltage is applied to these capacitors, and the corona discharge starting voltage (CSV) and corona discharge extinguishing voltage (CEV) are
) i was measured. The measurement temperature is 30°C. The measurement results are shown in Table 2.

In addition, the lifespan of the condenser→-1 was determined by applying a constant AC voltage L2 to an oil-impregnated capacitor prepared in the same manner and measuring the time until the capacitor was destroyed.Table 2 shows excludes the maximum and minimum values from among the breakdown times of seven capacitors impregnated with the same insulating oil, and indicates the average breakdown time (Wk) of the remaining five capacitors. is shown as a relative value, that is, the insulating oil of 100% alkyl biphenyl serving as a paste is shown as 1.0.

Table 2 From the results in Table 2, it can be seen that the insulating oil of the present invention contains capacitor K! It is clear that the capacitor exhibits much better performance than the capacitor impregnated with monoisozolobyl biphenyl alone, and its compatibility with the twisted plastic film is also satisfactory.

In addition, insulating oil Nα19 and N[L
No. 20 was not compatible with plastic film, and it was problematic to use it in oil-impregnated electrical equipment using plastic.

As explained above, the electrical insulating oil of the present invention is an electrical insulating oil that has excellent compatibility with a plastic film, improves its dielectric strength, and has excellent stability against discharge energy. In particular, plastics, for example polyolefins such as polypropylene, in the form of films can be effectively used for impregnating oil-impregnated electrical equipment in which at least a portion of the insulator (dielectric) is used.

Claims (3)

[Claims] (1) An electrical insulating oil comprising (a) one or more alkylbiphenyls and (b) one or more olefins having two fused or non-fused aromatic rings. (2) The electrical insulating oil according to claim 1, wherein the alkyl biphenyl is monoisopropylbiphenyl. (3) Claims characterized in that the electrical insulating oil contains 0.001 to 5 weight amount of antioxidant 1 agent;
Electrical insulating oil as described in Section 1 or Section 2.