JPH0668712A - Heat resistant insulating paint - Google Patents

Abstract

PURPOSE:To provide heat-resistant insulating paint which excels in the property of close adhesion to copper and heat resistance and particularly the characteristic of heat shock and besides can provide an insulating electric wire of excellent external appearance. CONSTITUTION:This paint is characterized in that ethanolamine of 1.0 to 2.5 parts by weight is added to the resin component of polyester imide resin paint of 100 parts by weight obtained by reacting tricarboxylic acid anhydride to polyatomic alcohol. With the heat resistance insulating paint, an insulating electric wire which excels in heat resistance, mechanical characteristics, external appearance when baked at a high temperature and at a high linear speed, and also heat shock resistance characteristics may be manufactured, and at the same time it excels in the storage stability of an insulating paint.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant insulating paint, more specifically, adhesion to copper and heat resistance, particularly heat-resistant insulation which is excellent in heat shock properties and which can obtain an insulated wire having a good appearance. It concerns paints.

[0002]

2. Description of the Related Art A commercially available polyesterimide resin coating having a good heat shock property, which has been used in the past, is a trade name of Isomid 40S manufactured by Nippon Schenectady.
There is T. However, when this insulating paint is used, an insulated wire having excellent heat resistance, thermal shock resistance, mechanical properties, etc. can be obtained, but on the other hand, there is a problem that productivity is poor. Normally, improving productivity is one of the important factors for reducing manufacturing costs, but when manufacturing paint-baked insulated wires, the insulating paint is baked at the highest temperature possible to increase the wire speed of baking. Is essential for improving productivity.

At this time, what becomes a problem is the appearance of electric wires at high temperature and high wire speed, which is a severe condition for insulating paints. In each case, it is known that the appearance of the electric wire at high temperature and high linear velocity causes a poor appearance, which is commonly called "granular skin". On the other hand, when a good polyester-imide resin coating that does not have a “skin-skin” appearance at high temperature and high linear speed baking is used, the resin film obtained has excellent heat resistance and mechanical properties, Under the current circumstances, the heat shock characteristics are clearly deteriorated and the characteristics and the appearance of the electric wire are not well balanced.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a heat-resistant insulation capable of obtaining an insulated electric wire which is excellent in adhesion to a copper conductor and heat shock characteristics, and which has a good appearance of the electric wire at the time of high temperature and high wire speed baking. The purpose is to obtain a paint.

[0005]

According to the present invention, 1.100 parts by weight of triethanolamine is added to 100 parts by weight of a resin component of a polyesterimide resin coating obtained by reacting a tricarboxylic acid anhydride, a diamine and a polyhydric alcohol. It is characterized by adding 0 to 2.5 parts by weight.

The polyester-imide resin used in the present invention is prepared by reacting a tricarboxylic acid anhydride with a diamine (preferably an aromatic diamine) to form a diimidedicarboxylic acid, introducing an imide bond, and reacting this with a polyhydric alcohol. By doing so, an ester bond is introduced to obtain the intended polyesterimide resin. As the tricarboxylic acid anhydride, trimellitic acid anhydride is suitable,
A part of it may be replaced with terephthalic acid or isophthalic acid. The diamine is preferably an aromatic diamine, and examples thereof include 4,4′-diaminodiphenylmethane. Examples of the polyhydric alcohol that forms the ester bond include tris (2-hydroxyethyl)
Isocyanurate, ethylene glycol, glycerin and the like can be used.

In the present invention, the reason why the amount of triethanolamine added to the polyesterimide resin is limited to 1.0 to 2.5 parts by weight with respect to 100 parts by weight of the resin content of the insulating coating is that the addition of less than 1.0 parts by weight. , The insulating film obtained by coating and baking does not exhibit sufficient heat shock resistance, and when added in excess of 2.5 parts by weight, the insulated wire obtained using this paint shows good heat shock characteristics. However, on the other hand, this resin coating material is strongly affected by the decomposition of the main chain of the polyesterimide resin by the added ethanolamine, causing a large decrease in viscosity, and the storage stability of the insulating coating material is significantly reduced. The preferred addition range of triethanolamine is within the range of 1.5 to 2.0 parts by weight with respect to 100 parts by weight of the resin component in the paint.

[0008]

[Function] By adding a small amount of triethanolamine to the polyesterimide resin solution, the adhesiveness with copper conductors and heat shock resistance are similar to those of this resin coating without lowering the heat resistance and mechanical properties. It is possible to obtain an insulated wire which is excellent and has a good appearance when it is baked at high temperature and high wire speed.

[0009]

【Example】

(Examples 1-2 and Comparative Examples 1-3) 1 mol of trimellitic anhydride and 4,4'-diaminodiphenylmethane 0.5
Mol and tris [2-hydroxyethyl) isocyanurate 0.5 mol and dimethyl terephthalate 0.5 mol were reacted by heating, and the reaction product was dissolved in cresol to obtain a polyesterimide resin coating having a resin concentration of 38% by weight. Triethanolamine was sufficiently agitated with 100 parts by weight of the non-volatile resin content in the obtained polyesterimide resin coating material at an addition amount shown in Table 1 below to obtain an insulating coating material. Each of the obtained insulating coatings was applied and baked on a copper wire having a diameter of 1.0 mmφ to produce polyesterimide resin insulated wires of Examples 1-2 and Comparative Examples 1-3 having a film thickness of 32 μm. The baking was performed by using a vertical baking machine having a furnace length of 5 m, and at a baking temperature of 500 ° C. in the hardening region.

(Comparative Example 4) As a polyesterimide resin coating material, an insulating coating material (trade name: ISOMID 40ST) manufactured by Nippon Schenectady is used. This insulation paint is applied on a copper wire with a diameter of 1.0 mmφ and baked to give a film thickness of 32 μm.
To obtain a polyesterimide resin insulated electric wire.

Obtained Examples 1-2 and Comparative Examples 1-4
Each of the insulated wires was examined for heat shock resistance, heat resistant softening temperature, one-way wear, adhesion, and wire appearance. The results are also shown in Table 1. Regarding heat shock resistance, after 20% elongation, 200 ° C x 30
The impact resistance under the condition of minutes was evaluated. Moreover, Examples 1-2
And each of the insulating paints of Comparative Examples 1 to 4 at 60 ° C. for 3 days.
While maintaining the space, the viscosity change of the coating material at 30 ° C. was measured with a B type viscometer. The results are also shown in Table 1.

[0012]

[Table 1]

As is apparent from Table 1, the insulated wire obtained by the insulating coating material of the present invention has heat shock resistance,
Excellent adhesion, appearance of electric wire, etc., and good storage stability (pot life) of paint. On the other hand, the insulated wire obtained by using the commercially available insulating paint (Comparative Example 4) has a poor appearance of the wire and has a poor skin appearance, and is defined in Comparative Example 1 in which no triethanolamine is added and the present invention. The insulated wire obtained by using the comparative example 2 product of the insulating paint added in an amount out of the range has poor heat shock resistance, and the comparative example 3 product is not only poor in workability because the initial viscosity of the resin paint is too low. Without
The change in viscosity of the insulating paint was also large.

[0014]

EFFECTS OF THE INVENTION According to the heat-resistant insulating coating material of the present invention, an insulated wire having excellent heat resistance, mechanical properties, and wire appearance at the time of high-temperature and high-speed wire baking can be produced, and an insulated wire excellent in heat shock resistance can be produced. It has excellent storage stability of insulating paint.

Claims (1)

[Claims] 1. 1.0 to 2.5 parts by weight of triethanolamine is added to 100 parts by weight of a resin component of a polyesterimide resin coating obtained by reacting a tricarboxylic acid anhydride, a diamine and a polyhydric alcohol. A heat-resistant insulating paint characterized by