JPH05339523A - Insulating varnish and insulated wire - Google Patents

Abstract

PURPOSE:To provide a polyamide-imide insulating varnish with which granulation and foaming can effectively be prevented irrespective of rapid curing and a polyamide-imide-coated insulated wire produced by applying the varnish to a conductor and baking the same. CONSTITUTION:The title varnish comprises 100 pts.wt. aromatic polyamide-imide resin synthesized from an acid component comprising 1-20 mole % aromatic tetrabasic acid component and an aromatic diisocyanate resin, 1-15 pts.wt. bisphenolic epoxy resin having a softening point of 40-130 deg.C and an appropriate amount of an aromatic polyisocyanate resin. A polyamide-imide-coated insulated wire is produced by applying the insulating varnish to a conductor and baking the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulating paint and an insulated wire. More specifically, the present invention relates to a polyamide-imide insulating coating having excellent fast-curing properties and a polyamide-imide insulating electric wire formed by coating and baking the coating on a conductor.

[0002]

2. Description of the Related Art Polyamideimide insulated wires have excellent heat resistance, mechanical properties, refrigerant resistance, etc., and are widely used as heat resistant enameled wires having a heat resistant classification of H to C class. For example, polyamide-imide insulated wire is used for electric tool motors, wiper motors, motors for cooling equipment,
It is used as a coil enamel wire for F to H class general-purpose motors and has high reliability.

[0003]

However, the polyamide-imide type insulated electric wire has a drawback that the workability of coating and baking the polyamide-imide type insulating paint on the conductor wire is inferior from the viewpoint of the enamel wire manufacturer.

That is, the polyamide-imide type insulating coating material has a drawback that when it is applied and baked on a conductor at a high temperature, particles and foaming are likely to occur in the baked enamel film. For this reason, in the production of a polyamide-imide insulated wire, the coating amount is reduced at one time so that particles and foaming can be suppressed, the baking temperature is lowered, and the baking is performed at a low speed.

For this reason, it is difficult to improve the productivity per enameled wire coating machine.

The present invention has been made in view of such a point, and its purpose is to solve the above-mentioned drawbacks of the prior art and to effectively suppress particles and foaming even when cured at a high speed. It is an object of the present invention to provide a polyamide-imide insulating coating material capable of achieving the above, and a polyamide-imide insulating electric wire formed by applying and baking the insulating coating material on a conductor.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to provide an aromatic polyamideimide resin synthesized from an acid component containing 1 to 20 mol% of an aromatic tetrabasic acid component and an aromatic diisocyanate resin. 1 part by weight of bisphenol-based epoxy resin having a thermal softening point of 40 to 130 ° C.
The present invention relates to an insulating coating material comprising 15 to 15 parts by weight and an appropriate amount of an aromatic polyisocyanate resin, and a polyamide-imide insulated wire formed by coating and baking the insulating coating material on a conductor.

In the present invention, the aromatic polyamideimide resin is limited to an aromatic polyamideimide resin synthesized from an acid component containing 1 to 20 mol% of an aromatic tetrabasic acid component and an aromatic diisocyanate resin. In the conventional aromatic polyamideimide resin synthesized from an acid component composed of 100 equivalent% of aromatic tribasic acid and an aromatic diisocyanate resin, it is not possible to compensate for the decrease in heat resistance due to the blended bisphenol epoxy resin, Moreover, the effect of suppressing particles and foaming is small, and as a result, high-speed curability cannot be expected.

Here, the aromatic tetrabasic acid component is defined as 1 to 20 mol% as the acid component. When it is 1 mol% or less, there is no effect of improving heat resistance, and on the contrary, when it is 20 mol% or more, an aromatic polyamide obtained is obtained. This is because the solubility of the imide resin in the organic solvent is suddenly deteriorated, and as a result, it cannot be practically used as an insulating paint.

The aromatic tetrabasic acid component used here is pyromellitic acid (benzene-1,2,4,5-tetracarboxylic acid) melophanoic acid (benzene-1,2,2,5).
3,5-tetracarboxylic acid), benzophenonetetracarboxylic acid and the like can be used. Particularly, pyromellitic acid and benzophenone tetracarboxylic acid are suitable. Further, the above aromatic tetrabasic acid anhydride can also be used.

In the present invention, the epoxy resin to be blended with 100 parts by weight of the aromatic polyamideimide resin is limited to the bisphenol type epoxy resin having a thermal softening point of 40 to 130 ° C. because the bisphenol having a thermal softening point of 40 ° C. or lower is used. This is because the molecular weight of the epoxy resin is too low and it is easily decomposed by heat during baking at high temperature, resulting in the generation of particles and foaming. On the contrary, the bisphenol epoxy resin having a softening point of 130 ° C or higher has a large molecular weight. As a result, the compatibility with the amide-imide resin is lowered, the cloudiness of the coating material is accelerated, and the storage stability of the coating material is deteriorated.

Here, as the bisphenol-based epoxy resin having a thermal softening point of 40 to 130 ° C., Epicoat 1001, Epicoat 1004, and Epicoat 10 manufactured by Ciel Co., Ltd.
There is 07 etc.

The softening point here is 40 to 130.
The bisphenol-based epoxy resin content of 1 to 15
The limitation to the weight part is that if the compounding amount of the bisphenol-based epoxy resin is 1 part by weight or less, there is no effect of suppressing the particles and foaming, and conversely, if it is 15 parts by weight or more, the heat resistance of the obtained insulated wire sharply decreases. This is because.

In the present invention, as the aromatic polyisocyanate resin blended with 100 parts by weight of the aromatic polyamideimide resin, aromatic diisocyanate resin, aromatic triisocyanate resin and the like can be used. Further, as these aromatic polyisocyanate resins, a stabilized aromatic polyisocyanate resin obtained by stabilizing an isocyanate group with a phenol compound can be used. As the stabilized aromatic polyisocyanate resin, there is a Bayer DC
There are T-stables, etc.

The blending amount of the aromatic polyisocyanate resin is not particularly limited, but is preferably 1 to 15
Weight parts are appropriate. That is, when the blending amount of the aromatic polyisocyanate resin is 1 part by weight or less, the appearance of the obtained enameled wire is not improved, and conversely, when the blending amount of the aromatic polyisocyanate resin is 15 parts by weight or more, the appearance is proportional to the blending amount. This is because no improvement is observed and the heat resistance of the obtained enamel wire is reduced.

[0016]

The insulating paint and the insulated wire of the present invention use an aromatic polyamide-imide resin synthesized from an acid component containing 1 to 20 mol% of an aromatic tetrabasic acid component and an aromatic diisocyanate resin. A bisphenol-based epoxy resin 1 whose base resin itself has remarkably improved heat resistance and functionality and which has a thermal softening point of 40 to 130 ° C.
That is, the curing reaction between ˜15 parts by weight and an appropriate amount of the aromatic polyisocyanate resin can be effectively caused to effectively suppress the abnormal curing reaction leading to particles and foaming.

As a result, a polyamide-imide insulating coating material which can effectively suppress particles and foaming even when it is rapidly cured is obtained. Further, by rapidly curing the insulating coating material on a conductor, the productivity of the polyamide-imide insulated wire is improved. And the quality can be significantly improved.

[0018]

EXAMPLES Next, examples of the insulating paint and the insulated wire of the present invention will be described together with comparative examples.

[Comparative Example 1] A resin component concentration was obtained by reacting trimellitic anhydride and 4,4'-diphenylmethane diisocyanate in N-methylpyrrolidone at a molar ratio of 1: 1.02. Is a 60% polyamide-imide paint, and then N-methylpyrrolidone /
It was diluted with a dimelformamide mixed solvent to obtain a polyamide-imide coating having a resin concentration of 30%.

Next, the resin concentration thus obtained is 30
% Polyamide imide coating on a conductor wire with a conductor diameter of 1.0 mmφ, and then squeezing off excess paint with a die and passing it through an enamel wire baking furnace with an effective furnace length of 6 m and a furnace temperature of 480 ° C. Baked. The coating and baking of this coating material were repeated a plurality of times to obtain a polyamide-imide insulated electric wire of Comparative Example 1 having an enamel coating thickness of 39 μm.

[Comparative Example 2] A polyamide-imide insulating coating composition was obtained by mixing 20 parts by weight of Epicoat 1007 with 100 parts by weight of the polyamide-imide resin of the polyamide-imide coating of 30% used in Comparative Example 1.

Next, the polyamideimide-based insulating coating material of Comparative Example 2 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

[Comparative Example 3] Trimellitic anhydride / pyromellitic acid = 99.5 mol% / 0.5 as an acid component
A polyamideimide resin was prepared in the same manner as in Comparative Example 1 except that mol% was used, and Epicoat 10 was prepared in the same manner as in Comparative Example 2.
20 parts by weight of 07 was blended to obtain a polyamide-imide insulating coating material of Comparative Example 3 having a solid content concentration of 30%.

Next, the polyamide-imide insulating coating material of Comparative Example 3 thus obtained was applied and baked onto a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

[Comparative Example 4] Trimellitic anhydride / pyromellitic acid = 75 mol% / 25 mol% as an acid component
Was used in the same manner as in Comparative Example 3 except that
Comparative Example 4 in which 20 parts by weight of 7 is blended and the solid content concentration is 30%
Polyamide-imide insulating paint of

Next, the polyamide-imide insulating coating material of Comparative Example 4 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

[Comparative Example 5] 20 parts by weight of Epicoat 1007 and 0.5 part by weight of D-CT stable were added to 100 parts by weight of polyamideimide resin of the polyamideimide insulating coating composition of Comparative Example 4. The polyamide-imide insulating coating material of Comparative Example 5 having a solid content concentration of 30% was used.

Then, the polyamide-imide insulating coating material of Comparative Example 5 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

Comparative Example 6 Solid content was obtained by blending 20 parts by weight of Epicoat 1007 and 20 parts by weight of D-CT stable with 100 parts by weight of polyamideimide resin of the polyamideimide insulating coating composition of Comparative Example 4. Concentration is 3
The polyamide imide-based coating material of Comparative Example 6 was 0%.

Then, the polyamide-imide insulating coating material of Comparative Example 6 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

Example 1 As an acid component, trimellitic anhydride / pyromellitic acid = 99.0 mol% / 1.0
Polyamideimide resin solution having a resin concentration of 60% by reacting these acid components and 4,4′-diphenylmethane diisocyanate in N-methylpyrrolidone in the same manner as in Comparative Example 1 except that mol% was used. After that, 15 parts by weight of Epicoat 1007 and 15 parts by weight of D-CT-Stable were added, and then diluted with a mixed solvent of N-methylpyrrolidone / dimerformamide to obtain a solid content of 30%. The polyamide imide-based paint of No. 1 was used.

Next, the polyamideimide-based insulating coating material of Example 1 thus obtained was applied and baked onto a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

[Example 2] Trimellitic anhydride / pyromellitic acid = 90.0 mol% / 10.
15 parts by weight of Epicoat 1007 and 1 part of D-CT-stable were prepared in the same manner as in Example 1 except that 0 mol% was used.
5 parts by weight was added to obtain a polyamideimide-based coating material of Example 2 having a solid content of 30%.

Next, the polyamideimide-based insulating coating material of Example 2 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

Example 3 As an acid component, trimellitic anhydride / pyromellitic acid = 80.0 mol% / 20.
15 parts by weight of Epicoat 1007 and 1 part of D-CT-stable were prepared in the same manner as in Example 1 except that 0 mol% was used.
5 parts by weight was added to obtain a polyamideimide-based coating material of Example 3 having a solid content of 30%.

Then, the polyamide-imide insulating coating material of Example 3 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

[Example 4] 15 parts by weight of Epicoat 1007 and 5 parts by weight of D-CT stable were added to 100 parts by weight of the polyamideimide resin in the polyamideimide insulating coating composition of Example 3 to prepare a resin component. Concentration is 30
% Of the polyamide-imide-based paint of Example 4.

Then, the polyamide-imide insulating coating material of Example 4 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

Example 5 Solid content was obtained by blending 5 parts by weight of Epicoat 1007 and 5 parts by weight of D-CT stable with 100 parts by weight of polyamideimide resin of the polyamideimide insulating coating material of Example 3. 30% concentration
The polyamide-imide type coating material of Example 5 was used.

Then, the polyamide-imide insulating coating composition of Example 5 thus obtained was coated and baked on a conductor wire having a conductor diameter of 1.0 mmφ in the same manner as in Comparative Example 1 and baked. Got

Next, a characteristic test was conducted on the thus obtained polyamide-imide insulated wires of Comparative Examples 1-6 and Examples 1-5.

The test method of the characteristic test is JIS-C3003.
Went according to.

Table 1 shows the results of these tests.

Appearance The appearance inspection judges whether the appearance of the insulated wire under test is good or not,
Good ones are indicated by ◯, and bad ones are indicated by x.

Flexibility The flexibility test first takes the insulated wires under test and then
It was stretched by 0% and then wound around a winding rod having a conductor diameter n times. The results are shown by the minimum double diameter with no cracks on the surface coating.

Resistance to heat deterioration As for resistance to heat deterioration, first, the insulated wires to be tested are taken, then these are twisted and twisted, and then these are heat deteriorated at 220 ° C. for 7 days,
Finally, the dielectric breakdown voltage was measured for each of the sample not thermally deteriorated and the sample thermally deteriorated. The result is 6 when the residual rate of the dielectric breakdown voltage of the thermally deteriorated sample is 60% or more when the dielectric breakdown voltage of the sample that is not thermally deteriorated is 100, and is 6
Those of 0% or less are shown as x.

Further, the seizure speed ratio is shown as a speed ratio when the appropriate seizure speed in Comparative Example 1 is 1.

[0048]

[Table 1]

As can be seen from Table 1, in the polyamide-imide insulated wire of Comparative Example 1, foaming occurred in the enamel coating layer, resulting in poor appearance.

Further, a polyamideimide-based insulating coating material obtained by mixing 20 parts by weight of Epicoat 1007 with 100 parts by weight of the polyamideimide resin of the polyamideimide coating of 30% used in Comparative Example 1 was applied and baked on a conductor wire. The resulting polyamide-imide insulated wire of Comparative Example 2 showed inferior heat resistance.

Trimellitic anhydride as acid component /
Pyromellitic acid = 99.5 mol% / 0.5 mol% Polyamideimide resin synthesized using Epicoat 100
The polyamideimide-based insulated wire of Comparative Example 3 obtained by applying and baking a polyamideimide-based insulating coating material containing 20 parts by weight of No. 7 deteriorates in heat resistance.

Trimellitic anhydride / an acid component
The polyamideimide resin synthesized by using pyromellitic acid = 75 mol% / 25 mol% has poor solubility in an organic solvent, and thus the polyamideimide insulating coating composition of Comparative Example 4 has poor paint stability. The appearance and heat resistance of the polyamide-imide insulated wire of Comparative Example 4 deteriorated.

Further, Comparative Example 5 and Comparative Example in which the polyamide-imide insulating coating composition of Comparative Example 4 and D-CT stable were mixed and the polyamide-imide insulating coating composition of Comparative Example 6 was applied and baked on a conductor wire. Similarly, the polyamide-imide insulated wire of No. 6 had poor appearance and heat resistance.

On the other hand, the polyamide-imide insulating coatings of Examples 1 to 5 of the present invention have good coating stability, and the polyamide-imide insulating coatings obtained by coating and baking these polyamide-imide insulating coatings on the conductors. The electric wire exhibited excellent properties in terms of appearance, heat resistance, and flexibility, and the baking speed was improved by 40% or more as compared with the insulating paints of Comparative Examples 1-5.

[0055]

EFFECT OF THE INVENTION The insulating coating of the present invention has excellent coating stability and exhibits remarkable rapid curing property, and a polyamide-imide insulated wire formed by coating and baking the insulating coating on a conductor has an appearance, Both heat resistance and flexibility can exhibit excellent characteristics and are industrially useful.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI technical display location H01B 3/30 F 9059-5G (72) Inventor Akio Mitsuoka 4-10 Kawajiri-cho, Hitachi-shi, Ibaraki No. 1 Inside the Toyoura Plant of Hitachi Cable Co., Ltd. (72) Inventor Yoshiyuki Tetsu No. 4-10-1 Kawajiri-cho, Hitachi City, Ibaraki Prefecture Inside the Toyoura Plant of Hitachi Cable Co., Ltd. (72) Shinichi Oda 1-chome Shimohozumi, Ibaraki City, Osaka Prefecture 1-2, Nitto Denko Corporation (72) Inventor Teruhiko Akimoto 1-2-1, Shimohozumi, Ibaraki City, Osaka Prefecture Nitto Denko Corporation

Claims (2)

[Claims] 1. An insulating paint comprising 100 parts by weight of an aromatic polyamide-imide resin and an epoxy resin and an aromatic polyisocyanate resin dissolved in an organic solvent, wherein the aromatic polyamide-imide resin contains 1 part of an aromatic tetrabasic acid component. ~ 20
The epoxy resin comprises a bisphenol-based epoxy resin having a thermal softening point of 40 to 130 ° C., and the bisphenol-based epoxy resin is compounded. Insulating paint, characterized in that the amount is 1 to 15 parts by weight. 2. An insulated wire comprising a polyamide-imide insulating layer provided on a conductor directly or via another insulating layer,
The polyamide-imide insulating layer has an aromatic tetrabasic acid component of 1
Aromatic polyamide-imide resin synthesized from an acid component consisting of ˜20 mol% and an aromatic diisocyanate resin 1
An insulated wire, comprising 1 to 15 parts by weight of a bisphenol-based epoxy resin having a heat softening point of 40 to 130 ° C., and an appropriate amount of an aromatic polyisocyanate resin, in 00 parts by weight.