JPS59177808A - Improved electrically insulating oil composition - 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] Related. More specifically, the present invention relates to an electrically insulating oil composition suitable for impregnating oil-impregnated electrical equipment such as condensers and cables.

In recent years, oil-impregnated electrical equipment such as power cables and power capacitors has been trending toward higher voltage and larger capacity as demand for power increases. Accordingly, as a dielectric or an insulator, a plastic film with higher dielectric strength has come to be used as part or all of the conventional insulating paper. However, unlike insulating paper, this plastic film has poor oil impregnation properties, and depending on the type of insulating oil, the plastic film may melt, stiffen, or swell. For this reason, voids, which are unimpregnated areas, are likely to occur on the surface of the film, and as a result, corona discharge is likely to occur. Therefore, oil-impregnated electrical equipment using Plastinok film can be used for higher pressure, larger capacity, and longer life. My sister achieved her request. So, such a dielectric (insulator)
Electrical insulating oils have been developed that are suitable for
There are aromatic insulating oils such as diarylalkane, alkylnaphthalene, and alkyl biphenyl. These insulating oils are suitable for the above-mentioned dielectric (insulator), have low power loss, and have a very high withstand voltage, and are therefore considered to be suitable electrical insulating oils.

On the other hand, from the standpoint of safety and disaster prevention, electrical insulating oils are also required to be flame retardant. However, all of the aromatic insulating oils having two aromatic rings are easily flammable.

Therefore, in order to meet these requirements, flame retardancy was achieved by mixing an aromatic phosphate ester with an aromatic insulating oil having two aromatic rings such as aryl alkanes, alkylnaphthalenes, and alkyl biphenyls. It has been proposed to give
54-155457, Special Publication No. 57-3208).

However, in order to obtain sufficient flame retardancy in the flame retardant insulating oil obtained in this way, it is necessary to increase the mixing ratio of the aromatic phosphate ester. However, while this improves flame retardancy, it has the drawbacks of increased dielectric loss and decreased hydrogen gas absorption.

On the other hand, electrical insulating oils made of aromatic hydrocarbons having three aromatic rings, such as triarylalkano, are known. The flame retardancy of this compound is superior to that of electrical insulating oils made from aromatic hydrocarbons having two aromatic rings, but
It's not always satisfying. Furthermore, even if the above-mentioned aromatic phosphate ester is mixed in order to improve flame retardancy, the viscosity increases and impregnation becomes difficult, so it is not suitable as an insulating oil for impregnation. In other words, electrical equipment impregnated with highly viscous electrical insulating oil has the disadvantage that it is difficult to generate corona discharge. Very often, these accumulated decomposition products result in a greatly increased discharge rate, resulting in the destruction of oil-impregnated electrical equipment.

In other words, an object of the present invention is to develop an electrical insulating oil suitable for manufacturing small-sized, low-loss oil-impregnated electrical equipment in view of the circumstances mentioned above. Our goal is to provide highly safe electrical insulating oil that takes advantage of its characteristics.

The present invention provides (a) a fused or non-fused aromatic ring with 3
One type of aromatic hydrocarbon having a ring (l-1: 2 f
m or more, and (b) one or more compounds selected from the group consisting of orthophosphoric acid esters represented by the following general formula (D) and phosphite esters represented by the general formula (■)
The present invention relates to an electrical insulating oil composition comprising more than one species.

General formula General formula Here, in the above general formulas (■) and (n), R1
, R2 and R3 each represent the same or different alkyl groups having 6 or less carbon atoms.

The aromatic hydrocarbons described in Section 2 (a) have not been generally used for impregnation, but they can be used for the first time by mixing them with the above-mentioned orthophosphoric acid ester and/or phosphorous acid ester. It is now suitable for impregnating oil-impregnated electrical equipment.

The aromatic hydrocarbon having three fused or non-fused aromatic rings in item (a) is, for example, the following general formula (
There are aromatic hydrocarbons such as those represented by III) and (TV).

General formula % Formula % () General formula (R7) y ... (IV) In the above general formulas (n, f) and (IV), R4, R5 and R9 have a carbon number of 1 to 0 is a group derived from a saturated aliphatic hydrocarbon. XIY and Z are each an integer of 0 to 3, and y R11, y R7 and 6 R8 are the same or different groups, and each has a hydrogen atom or a carbon number of 1 to 4. is an alkyl group.

The aromatic hydrocarbon of the above general formula (■I') is benzene,
The aromatic hydrocarbon of the general formula (IV) obtained by alkylation of alkylbenzene etc. with styrenes is a saturated linear trimer formed by trimerization of styrenes, or an unsaturated linear trimer of styrenes. It can also be obtained by B line 7, biplane, benzene, and alkylbenzene rucination.

Specific compounds represented by formula (II'I) include (ethylphenyl)ethyl-phenylethyl-benzenylphenylethyl-benzene; (phenylethyl-ethylbenzene; (phenylethyllene); dibenzylbenzene; Examples include dibenzyl l-/renin.

Specific compounds represented by the formula (TV) include 1-xylyl-1,3-diphenylphyntane; 1-tolyl-1,3-diphenylphyntane; -ethylphenyl-1,3-diphenylphtane; ．． 4-diphenyl-4-#flupenutane; 2-quinylru2. 4-diphenyl-4-methylpentane etc. 75: Listed.

Furthermore, examples of the aromatic hydrocarbon having three fused or non-fused aromatic rings include the following compounds.

(a) Aromatic carbons having two fused or non-fused aromatic rings such as biphenyl, naphthalene, acerafthene, fluorene, or cyclic dimers of these alkylstyrenes (alkylated with fs hydrogen nystyrenes) Compounds that can be discovered.

(Example) An aromatic hydrocarbon having three fused 4'' or non-fused aromatic rings, such as terphenyl, anthracene, fepunthrene, or an alkyl substituted product thereof.

C → Aromatic carbon having 4 or more fused or 11-3 condensed aromatic rings with chrysene and pyrene (by partial nuclear hydrogenation of arsenium, 3 fused or non-fused aromatic rings and 1 ~Aromatic hydrocarbons.

The aromatic hydrocarbons of item (a') of the present invention, that is, the aromatic hydrocarbons of items (a) to (c) represented by the general formulas (a and (IV)), are suitably liquefied at room temperature. A compound having the following formula (m) can be selected and used in the present invention.Among the aromatic hydrocarbons having three fused or non-fused aromatic rings, particularly preferred aromatic hydrocarbons are those represented by the general formula (m). and (IV).

In the present invention, these aromatic hydrocarbons have the formula (
The orthophosphoric acid ester of I) and/-i or the phosphorous acid ester of formula (TI) are mixed. The reason why the number of carbon atoms in the alkyl group is limited to 6 or less in these aliphatic pressurized phosphoric acids or phosphite esters is that orthophosphoric acid or phosphite esters having an alkyl group with more than 6 carbon atoms have a high viscosity. This is because it is too expensive and is therefore not suitable as an impregnating oil.

Specifically, as the orthophosphoric acid ester represented by the general formula (I), tributyl phosphate (TMP)
) ethyl phosphate (TFJP), tributyl phosphate (TBP), triamyl phosphate (TAP) and trihexyl phosphate (T
HP') etc.

Further, as the phosphite represented by the above formula (TI), dibutyl-butylphosphonate (DBBP)
, dipropyl-propylphosphonate (DPPP),
These include noamyl-amyl phosphonate (DAAP) and dihegysyl-hexyl phosphate (DI-IHP).

By using the above aliphatic phosphate ester as the phosphoric ester, an insulating oil with much lower viscosity and excellent impregnating properties can be produced compared to the case where aromatic phosphate ester is used and mixed. As a result, oil-impregnated electric equipment impregnated with this insulating oil can be made higher in pressure and smaller in size, and can have high reliability.

Furthermore, compared to the conventionally known electrical insulating oil consisting of an aromatic insulating oil having two aromatic rings and an aromatic phosphate ester, the composition of the present invention has a lower mixing ratio of the phosphate ester. Sufficient flame retardancy can be obtained even if the size is small. It's ox.
Although it has sufficient flame retardancy, it has excellent performance such as low dielectric loss and high hydrogen gas absorption.

The mixing ratio of the aromatic hydrocarbon having three fused or non-fused aromatic rings in item (a) of the present invention and the orthophosphoric acid and/or phosphorous acid ester in item (b) is as follows: The phosphoric ester (b) can be selected arbitrarily depending on the viscosity, electrical properties, hydrogen gas absorbency, etc., but the phosphoric acid ester (b) may have a content of 5 to 60% in the composition prepared by mixing both components. % by weight is preferred. Moreover, the weight ratio is more preferably 10 to 50.

Note that compounds known to be added to insulating oils, such as epoxy compounds, can also be further added to the composition of the present invention.

The electrical insulating oil of the present invention has excellent electrical properties, low viscosity, hydrogen gas absorption, and flame retardancy, and can be used in a wide range of applications such as power oil-impregnated capacitors, power oil-impregnated cables, and oil-immersed transformers. It is safe to use. In particular, polypropylene (P
P) It can be suitably used in devices that use plastics such as polyolefins such as polymethylpentene, and polyesters. These plastics are used, for example, in the form of film over film. In particular, since a low viscosity flammable insulating oil can be obtained, all plastics, such as all PP
When used in film capacitors, etc., it exhibits excellent current (11t).

Next, the electrical insulating oil composition of the present invention will be explained in detail with reference to Examples.

Examples 1 to 4 Styrene was added dropwise to a mixture of xylene and ethylbenzene to cause a reaction in the presence of an e-catalyst.

Next, this reaction product was subjected to precision distillation to separate a fraction having a boiling point range of 340 to 400 C in terms of normal pressure. This fraction contained 98% by weight of compounds having three aromatic rings, such as distyrenated xylene and distyrenated ethylbenzene. As a result of the analysis, the above general formula (
The component represented by 1'lI) was 38% by weight, and the component represented by the general formula (IV) was 56% by weight. This fraction is hereinafter referred to as "distyrenated golden oil".

This distyrenated xylene oil is mixed with various aliphatic phosphate esters as shown in Table 1.
, its electrical properties, flammability, hydrogen gas absorption, viscosity, etc. were measured. The results are also shown in Table 1.

Comparative Example 1 Electrical insulation oil plates 11 to 13 were prepared by mixing l.recresyl phosphate (TCP) f and r as an aromatic phosphoric acid ester with distyrenated xylene oil.

Comparative Example 2 Electrical insulating oils A14 and 15 were prepared by mixing phenylxylylethane with TCP.

The physical properties of the electrical insulating oils of all comparative examples were measured in the same manner as in the above examples and are also shown in Table 1.

As can be seen from the results in Table 1, when aromatic phosphate ester is mixed with styrenated oil, the flame retardance is good, but the viscosity becomes high and the impregnating property is poor. Not suitable for The viscosity of this electrical insulating oil can be lowered by increasing the mixing ratio of aromatic Nisdel phosphate, but the viscosity becomes larger and the hydrogen gas absorption becomes worse (
Comparative example 1).

In Comparative Example 2, which uses an electrical insulating oil made of an aromatic hydrocarbon having two aromatic rings and an aromatic phosphate ester, the viscosity is low and good, but the flame retardance is poor, and the aromatic phosphate ester Although flame retardancy improves by increasing the mixing ratio of , δ scavenging and hydrogen gas absorption properties also deteriorate.

On the other hand, in the electrical insulating oil composition of the present invention,
Aliphatic phosphate esters or aliphatic phosphate esters exhibit excellent effects even when added in small amounts, and improve viscosity, flame retardancy, and
It has good physical properties such as anδ and hydrogen gas absorption, and is suitable as an electrical insulating oil.

Claims (1)

[Scope of Claims] (]) (a) one or more aromatic hydrocarbons having three fused or non-fused aromatic rings; and (b) an aromatic hydrocarbon represented by the following general formula 〇). An electrical insulating oil composition comprising one or more compounds selected from the group consisting of phosphoric acid esters and phosphite esters represented by the general formula (U), where the general formula is In (I) and (n), R1
, R2 and R3 each represent the same or different alkyl groups having 6 or less carbon atoms. (2) The electrical insulating oil composition according to claim 1, wherein the aromatic hydrocarbon is represented by the following general formula (III) and/or (IV), where the general formula: In the general formulas (III) and (TV), R<, R5 and Ro are groups derived from a saturated aliphatic hydrocarbon having 1 to 10 carbon atoms, and T! l'
+ Z is an integer from θ to 3, and y R6,
y R7s and two R8s are each the same or different group, and are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. (3) The electrical insulating oil according to claim 1 or 2, which contains 5 to 60 parts by weight of a phosphoric acid ester represented by the general formula (1) and/or (TI). Composition.