JPS6342804B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a heat-resistant insulated wire, particularly a heat-resistant insulated wire that can be used at high temperatures of 300° C. or higher. Traditionally known heat-resistant enamelled wires include polyimide wire, polyamide-imide wire,
There are polyester imide wires, etc., each starting from 220
It has heat resistance of 250℃, 180~220℃, and 155~180℃, and can be said to have considerable heat resistance, but since they are all made of organic insulation films, they decompose at high temperatures of around 400℃. Therefore, its use was limited to temperatures up to about 250°C. On the other hand, glass windings made by wrapping glass threads around a conductor to insulate them are also known as heat-resistant insulated wires, but such glass windings usually include glass threads and glass threads for the purpose of improving insulation and preventing fraying. An organic insulating paint is applied between the
Therefore, the heat resistance is only around 180℃,
Furthermore, it had the disadvantage of being inferior to Space Factor. In recent years, it has been used for nuclear power generation, geothermal power generation, and other special purposes.
There is a demand for magnet wires that can be used at high temperatures of 300°C or higher, and inorganic wires coated with inorganic materials are being considered, but such inorganic wires are generally porous and have poor flexibility and insulation, making them impractical. The current situation is that it has not been standardized. On the other hand, the present inventors studied polyborosiloxane resin, which has a skeleton of silicon, boron, and oxygen and can be used as an electrically insulating paint, and found that if it is mixed with an aromatic polyimide resin, it can be used even at high temperatures of 300°C or higher. Moreover, it was discovered that an insulated wire with no deterioration in flexibility or insulation properties could be obtained, and the patent was filed earlier. However, this product had insufficient mechanical strength and needed to be improved. The present invention has been made to improve this, and relates to a heat-resistant insulated wire in which an insulation coating of class H or higher is provided on a coated and baked layer of the above-mentioned mixed varnish of polyborosiloxane resin and aromatic polyimide resin. The aromatic polyimide resin solution used in the present invention is prepared by mixing 3.3'.4.4'-benzophenone tetracarboxylic dianhydride and a special aromatic diamine with cresol as described in Japanese Patent Publication No. 46-17145. (such as TVE5051 manufactured by Toshiba Chemical Co., Ltd.) is suitable.
Others, such as Pile ML (product name manufactured by DuPont),
Varnish obtained by addition reaction of pyromellitic dianhydride and 4,4′-diaminodiphenyl ether in a special polar solvent such as N-methylpyrrolidone (NMP) or dimethylacetamide (DMAc) at a low temperature of around 10°C. In some cases, it is a solution of polyamic acid resin, which is a precursor of polyimide, but due to the short life of the varnish, it requires low temperature storage, and the use of expensive special solvents. Group polyimide resin solutions are preferred. The polyborosiloxane resin used in the present invention is
(a) boric acid compounds such as orthoboric acid, metaboric acid, boric anhydride, boric acid methyl ester, borax,
(b) Silane compounds represented by SiX ₄ , SiRX ₃ , SiRR'X ₂ (wherein R and R' are methyl or phenyl groups,
X is a hydroxyl group or chlorine, and in the case where It is obtained by heating the polycondensate at 50 to 800°C to carry out a polycondensation reaction. When the reaction temperature is 300°C or higher, it is preferable to carry out the reaction under an inert atmosphere, and the reaction may be carried out in two stages. In the production of polyborosiloxane resins, it is desirable to use silanol compounds (hydroxysilanes), since the chlorine-containing silane (b) generates hydrogen chloride, which is unfavorable in terms of the working environment. Also, based on the total amount of boric acid compound (a) and silane compound (b),
If 5% by weight or more of silicone oil is added and the polycondensation reaction is carried out, it is desirable to use this method because a wire coating having superior flexibility can be obtained. The viscosity of silicone oil at 25℃ is
Dimethylsilicon or methylphenylsilicon or mixtures thereof of 1.0 centistokes, preferably 10 centistokes or more are suitable. The polyborosiloxane resin solution is obtained by dissolving the polyborosiloxane resin in a phenolic solvent such as cresol or a stoving solvent such as N-methylpyrrolidone (NMP). In the present invention, a varnish-like resin solution can be obtained by adding and dissolving a polyborosiloxane resin into an aromatic polyimide resin solution, but it is easier to mix the solutions together, and in that case, it is preferable to use the same type of solvent. desirable. For example, if the solvent for the aromatic polyimide resin solution is a phenolic solvent such as cresol, it is desirable to use a phenolic solvent for the polyborosiloxane resin solution.
In the case of a polar solvent such as DMAc, it is desirable to use NMP or DMAc for the polyborosiloxane resin solution. The reason for this is that when different types of solvents are mixed, the solubility of polyimide differs, causing separation and precipitation. In the present invention, the mixing ratio of the aromatic polyimide resin solution and the polyborosiloxane resin or resin solution can be appropriately selected depending on the required characteristics. For example, if mechanical properties are not so required but heat resistance is extremely required, the proportion of polyborosiloxane resin may be increased, and in the opposite case, the proportion of aromatic polyimide may be increased. However, when using a cresol solution of aromatic polyimide, if the solid content of the polyborosiloxane resin exceeds 70% of the total resin solid content, precipitation of the polyimide resin will occur, so the solid content of the polyborosiloxane resin is preferably 70% or less. The properties of these mixtures in the present invention are not the sum of the individual properties, but are significantly improved by mixing both. As the insulation coating of class H or higher used in the present invention,
THEIC polyesterimide resin, polyamideimide resin, polyimide resin, silicone resin, etc. If the thickness of these films is too thick, the heat resistance of the underlying layer will not be fully demonstrated, so the total film thickness should be
30% or less is preferable. In the present invention, the conductor used is Ni plating,
Heat-resistant conductors such as Ag-plated copper wires, Ag wires, and Ni wires are preferable, and the above-mentioned mixed varnish of polyborosiloxane resin and aromatic polyimide resin is applied and baked multiple times on these conductors using a conventional method.
Further, a varnish of grade H or higher is coated and baked on the varnish to obtain a heat-resistant insulated wire according to the present invention. Next, an example will be described. Example 1 50.0 mol% of diphenyldihydroxysilane, 34.0 mol% of boric acid, and 16.0 mol% of dimethyl silicone oil (average molecular weight 384) were placed in a reaction vessel equipped with a thermometer, a stirrer, and a condenser, and the temperature was gradually increased from room temperature to 400°C. The temperature was raised to (6 hours), and the reaction was further carried out at 400°C for 2 hours to effect condensation polymerization. This product was dissolved in cresol and the non-volatile content was 39.8%.
(300°C x 1 hour) to obtain a cresol solution of polyborosiloxane resin having a viscosity of 3.2 poise at 30°C. This polyborosiloxane resin solution and aromatic polyimide resin solution (TVE5051) have a resin solid content of 40% of the total resin solid content.
A varnish according to the present invention was obtained by mixing the varnish to 60%. This varnish had a non-volatile content of 21.3% (250°C x 1.5 hours) and a viscosity of 32.4 poise at 30°C.
Apply this varnish to a 1.0mmφ Ni plating wire (plating thickness
2μ), was coated and baked 8 times at a baking temperature of 450°C and a line speed of 8m/min using a vertical baking machine with a furnace length of 7.2m, and was dry-baked 3 times to produce an insulated wire with a coating thickness of 28μ. Then, apply TVE5051 three times on top of this.
An insulated wire with a total thickness of 37μ was obtained. The test results regarding the characteristics of the obtained insulated wire were as shown in Table 1. Example 2 HI-400, which is a polyamide-imide resin, was applied on the coating and baking layer of the mixed varnish of polyborosiloxane resin and aromatic polyimide resin obtained in Example 1.
(trade name, manufactured by Hitachi Chemical Co., Ltd.) was applied twice to obtain an insulated wire with a total thickness of 38 μm. Example 3 The polyborosiloxane resin obtained in Example 1 was mixed with TVE5051 so that the proportions were 50% and 50%,
This was baked under the baking conditions shown in Table 1, and TVE5051 was further applied three times to obtain an insulated wire with a total thickness of 37μ. Examples 4, 5, 6 54.6 mol% of diphenyldihydroxysilane, 36.3 mol% of boric acid, and 9.1 mol% of dimethyl silicone oil (average molecular weight 384) were subjected to a polycondensation reaction in the same manner as in Example 1, and dissolved in NMP. Non-volatile content 41.1%
(300°C x 1 hour) to obtain an NMP solution of polyborosiloxane resin having a viscosity of 0.5 poise at 30°C.
This is used as pile ML, 10%, 90% (Example 4),
50%, 50% (Example 5) 90%, 10% (Example 6)
Mixed so that
In Example 5, HI-400 (polyamideimide)
In Example 6, Isomid RH (trade name, manufactured by Nissoku Schenectaday Co., Ltd.), which is a THEIC polyester imide, was applied twice to obtain insulated wires having coating thicknesses of 39μ, 37μ, and 36μ, respectively. The test results for this product were as shown in Table 1. The comparative examples listed in the table do not have an upper layer, and Comparative Example 1 is coated with only the polyborosiloxane resin obtained in Example 1, and Comparative Example 2 is coated with the mixed varnish obtained in Example 3. The case of only the baked layer is shown.

【table】

[Table] As is clear from the above examples, the heat-resistant insulated wire according to the present invention has improved wear resistance and is extremely useful.

Claims (1)

[Claims] 1. A varnish-like resin solution prepared by mixing a polyborosiloxane resin or its solution with an aromatic polyimide resin solution is coated and baked on a conductor directly or through another insulating film, and then A heat-resistant insulated wire characterized by being provided with an insulation coating having heat resistance of class H or higher. 2. The heat-resistant insulated wire according to claim 1, wherein the thickness of the insulation coating having heat resistance of class H or higher is 30% or less of the total coating thickness.