JPS6161482B2 - - Google Patents

Description

[Detailed description of the invention]

FIELD OF THE INVENTION This invention relates to flame retardant electrical insulating oils. Widely used as a nonflammable electrical insulating oil
Since the use of PCBs was banned, there has been a demand for the development of an insulating oil that can replace them, but so far no nonflammable electrical insulating oil that can replace PCBs with a single substance has been found. Silicone oils, various ester oils, and the like have been proposed as flame-retardant electrical insulating oils, and some of them are actually used. They have a high flash point and are much less flammable compared to hydrocarbon insulating oils, but they do burn in the flammability test according to JIS C 2101-11, so it is difficult to tell which electrical insulating oils have sufficient flame retardancy. Good and difficult. The present invention aims to provide a novel flame-retardant insulating oil, and is characterized by using a mixture of a fatty acid ester of neopentyl polyol and an aromatic orthophosphorus ester. Conventionally, various flame-retardant insulating oils made by mixing flammable insulating oils and orthophosphoric acid esters have been proposed. Examples of such flammable insulating oils that have been used include hydrocarbon insulating oils such as Capacitor Oil S (manufactured by Nippon Oil Co., Ltd.) and alkylnaphthalene (manufactured by Kureha Chemical Industry Co., Ltd.), adipic acid esters, These include ester oils such as phthalic acid ester and trimellitic acid ester. However, flame-retardant insulating oil using hydrocarbon-based insulating oil has a low viscosity but a low flash point, while flame-retardant insulating oil using ester oil can have a high flash point but a high viscosity. Currently, there has been no flame-retardant insulating oil that has both of these characteristics, that is, a flame-retardant insulating oil that has a high flash point and a low viscosity. The present invention was made in view of the current situation, and an object of the present invention is to provide a flame-retardant electrical insulating oil having a high flash point and low viscosity. That is, the present invention relates to a flame-retardant electrical insulating oil prepared by mixing a fatty acid ester of neopentyl polyol with an aromatic orthophosphoric acid ester in an amount of 35 to 42% by volume or more. The fatty acid ester of neopentyl polyol that can be used in the present invention is preferably one in which the fatty acid residue mainly consists of oleic acid residue, and a specific example thereof is Unistar H381R (NOF Corporation).
(manufactured by). This Unistar H381R is the first
As shown in the table, this electrical insulating oil has a higher flash point than various electrical insulating oils, but has a lower viscosity.

[Table] In Table 1, the flash point was tested by the open cup method, and the burning rate was tested by the method of JIC C 2101-11. As shown in Table 1, Unistar H381R's flammability (burning rate) is higher than that of dimethyl silicone oil (50 cSt), and once ignited, combustion continues. However, products to which aromatic orthophosphoric acid esters such as tricresyl phosphate (hereinafter referred to as TCP) or cresyl diphenyl phosphate (hereinafter referred to as CDP) are added at 35 to 42% by volume have a high flash point. The flame does not continue to burn and the flame goes out, making it possible to use it as a flame-retardant insulating oil. Furthermore, since aromatic phosphoric acid esters have a low viscosity, they can also reduce the viscosity of the resulting flame-retardant insulating oil. Next, the flame-retardant insulating oil of the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. Example 1 Unistar H381R was used as a fatty acid ester of neopentyl polyol, and 35% by volume of TCP was added and mixed to obtain a flame-retardant insulating oil. Table 2 shows the results of measuring the viscosity, flash point, and burning rate of the obtained flame-retardant insulating oil. Each characteristic was measured according to the following method. (a) Viscosity (cSt) Measured using a capillary viscometer. (b) Flash point (℃) Measured according to the open cup method. (c) Burning rate (mm/sec) Measured according to the method of JIS C 2101. Example 2 A flame-retardant insulating oil was prepared in the same manner as in Example 1, except that the amount of TCP used was 40% by volume. Table 2 shows the properties of the obtained flame-retardant insulating oil. Examples 3 and 4 Flame-retardant insulating oils were prepared in the same manner as in Example 1, except that CDP was used in the amount shown in Table 2 instead of TCP. Table 2 shows the properties of the obtained flame-retardant insulating oil. Comparative Examples 1 and 2 Flame-retardant insulating oils were prepared in the same manner as in Example 1 or 3, except that the amount of TCP or CDP used was as shown in Table 2. Table 2 shows the properties of the obtained insulating oil. As Comparative Example 3, the characteristics of Unistar H381R are shown in Table 2.

【table】

[Table] As described above, according to the present invention, fatty acid ester of neopentyl polyol with low flammability,
In contrast, by mixing 35 to 42% by volume of aromatic phosphate ester, a flame-retardant electrical insulating oil with lower viscosity and a higher flash point can be obtained. When manufacturing various oil-filled electrical equipment using the flame-retardant electrical insulating oil of the present invention, no special operations are required. After the electrical insulating oil is subjected to vacuum degassing treatment, it can be injected into an electrical equipment container containing electrical windings or the like by vacuum injection or the like.

Claims (1)

[Claims] 1. A flame-retardant electrical insulating oil prepared by mixing a neopentyl polyol fatty acid ester with an aromatic orthophosphoric acid ester in an amount of 35 to 42% by volume. 2. The flame-retardant electrical insulating oil according to claim 1, wherein the fatty acid ester of neopentyl polyol has an oleic acid ester of neopentyl polyol as a main component. 3. The flame-retardant electrical insulating oil according to claim 1, wherein the aromatic orthophosphoric acid ester is tricresyl phosphate or cresyl diphenyl phosphate.