JPH065123A - Insulated electric wire - Google Patents

Abstract

PURPOSE:To provide an insulated electric wire having an insulated coating film excellent in flexibility and processing resistance by applying, to the electric wire, a polyamide-containing coating material including mainly a diisocyanate component, which includes a predetermined amount of an aromatic diisocyanate compound expressed by a specific formula, and an oxide component as raw materials, followed by baking. CONSTITUTION:A polyamide imide-containing coating material including at least a diisocyanate component and an oxide component (such as trimellitic acid anhydride) as raw materials is applied to an electric wire, followed by baking, thus obtaining an insulated electric wire having an insulated coating film. The diisocyanate component as the raw material includes 10-65mol.% (preferably 30-50mol.%) of an aromatic diisocyanate compound (naphthalene-1,5- diisocyanate or the like) expressed by Formula (wherein R<1>, R<2> are identical or different, and represent a hydrogen atom, an alkyl group, an alkoxyl group, or a halogen atom; (a) and (b) are an integer from 0 to 2, and a+b=2). Consequently, it is possible to enhance an elastic modulus of the insulated coating film so as to obtain the insulated coating film difficult to be damaged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire which is wound around a core of a motor and has excellent workability.

[0002]

2. Description of the Related Art In recent years, with the trend toward smaller size and lighter weight of equipment, there has been a demand for smaller and lighter motors with higher performance. To meet this requirement, it is necessary to wind more insulated wires around the motor core, but this will forcefully pack the insulated wires into the slots of the core, and there is a risk that the insulating coating will be damaged during the winding process. is there. When the insulating coating is damaged, there is a problem that a lare defect, a ground defect, etc. occur, causing a problem in the electric characteristics of the motor.

Therefore, an insulated wire having an insulating coating excellent in mechanical strength, which is formed by coating and baking a polyamideimide-based paint, is usually used for the above-mentioned use. As the polyamide-imide, the following formula (II)
The reaction product of diphenylmethane-4,4'-diisocyanate represented by and trimellitic anhydride is generally used (see, for example, JP-B-44-19274 and JP-B-45-27611). ).

[0004]

[Chemical 2]

[0005]

However, in recent years, motors having smaller size, lighter weight and better performance have been required, and in order to meet the demand, the winding amount of the insulated wire tends to further increase. However, the damage is increasing. Therefore, in order to reduce the damage of the insulating coating as much as possible, it has been studied to add a lubricant such as an organic or inorganic lubricant to the coating to impart lubricity to the surface of the insulating coating. However, damage to the insulating coating cannot be fundamentally resolved.

Although the occurrence of damage can be reduced by further improving the mechanical strength of the insulating coating, if the mechanical strength is simply improved, the coating becomes rigid and inferior in flexibility, and when the electric wire is bent. There is a problem that the workability of the insulated electric wire deteriorates because it is easily cracked or peeled off. The present invention is
The present invention has been made in view of the above circumstances, and an object thereof is to provide an insulated electric wire that has an insulating coating film that is excellent in flexibility and is not easily damaged, and that is excellent in work resistance.

[0007]

Means and Actions for Solving the Problems In order to solve the above problems, the present inventors investigated the structure of polyamide-imide, and as a result, the following general formula (I):

[0008]

[Chemical 3]

[In the above formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. a and b are 0 to 2 and a +
The number of b = 2 is shown. ] When the aromatic diisocyanate compound represented by the formula (3) is contained in the diisocyanate component as a raw material and a naphthalene ring is introduced into the structure of the polyamideimide, the elastic modulus of the insulating coating is improved and the flexibility is excellent. Moreover, they have found that an insulating coating that is not easily damaged can be formed. Then, as a result of further studying the content ratio of the aromatic diisocyanate compound represented by the general formula (I), the present invention has been completed.

That is, the insulated wire of the present invention is an insulated wire having an insulating coating formed by applying and baking a polyamideimide-based coating material containing at least a diisocyanate component and an acid component as raw materials. The aromatic diisocyanate compound represented by the general formula (I) is contained within a range of 10 to 65 mol%.

Among the diisocyanate components which are one of the raw materials for the polyamide-imide-based paint, specific examples of the aromatic diisocyanate compound represented by the general formula (I) are, for example, naphthylene-1,5-diisocyanate and naphthylene-1. , 4-diisocyanate, naphthylene-1,3-
Examples include diisocyanate. These may be used alone or in combination of two or more.

Among the above aromatic diisocyanate compounds, the naphthylene-1,5-diisocyanate represented by the following formula (Ia) is preferred because of its good structural balance, availability, cost and the like. Most preferably used in the present invention.

[0013]

[Chemical 4]

Other diisocyanates contained in the diisocyanate component together with the aromatic diisocyanate compound represented by the general formula (I) include, for example, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate and diphenylmethane-diisocyanate.
3,4'-diisocyanate, diphenyl ether-
4,4'-diisocyanate, benzophenone-4,
4'-diisocyanate, diphenyl sulfone-4,
4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-
Examples include various conventionally known diisocyanate compounds such as xylylene diisocyanate and p-xylylene diisocyanate. These may be used alone or in combination of two or more.

Among the above diisocyanate compounds,
In terms of availability and cost, the diphenylmethane-4,4'-diisocyanate represented by the formula (II) is
It is preferably used. Examples of the acid component that composes the polyamideimide-based coating together with the diisocyanate component include trimellitic acid, trimellitic anhydride, trimellitic acid chloride, and tribasic acid among trimellitic acid derivatives. In particular, trimellitic anhydride represented by the following formula (III) is preferably used in terms of availability and cost.

[0016]

[Chemical 5]

In the acid component, a tetracarboxylic acid anhydride or a dibasic acid such as pyromellitic acid dianhydride, biphenyltetracarboxylic acid dianhydride, benzophenonetetracarboxylic acid dianhydride, diphenylsulfonetetracarboxylic acid is used. Dianhydride, terephthalic acid, isophthalic acid, sulfoterephthalic acid, dicitric acid, 2,5-thiophenedicarboxylic acid, 4,5-phenanthrenedicarboxylic acid, benzophenone-4,4'-dicarboxylic acid, phthaldiimidedicarboxylic acid, biphenyldicarboxylic acid Acid, 2,6-naphthalenedicarboxylic acid, diphenyl sulfone-4,4'-
A part of dicarboxylic acid, adipic acid, etc. may be added.

The ratio of the aromatic diisocyanate compound represented by the general formula (I) in the diisocyanate component is limited to the range of 10 to 65 mol% for the following reason. That is, when the proportion of the aromatic diisocyanate compound represented by the general formula (I) is less than 10 mol%, the effect of adding the aromatic diisocyanate compound cannot be obtained, and the insulating coating tends to be damaged. On the other hand, when the proportion of the aromatic diisocyanate compound represented by the general formula (I) exceeds 65 mol%, the elastic modulus of the insulating coating is rather lowered and the insulating coating tends to be damaged, and the insulating coating becomes rigid and flexible. It is inferior and easily cracks or peels off.

The proportion of the aromatic diisocyanate compound represented by the general formula (I) in the diisocyanate component is preferably within the range of 30 to 50 mol%. From the above diisocyanate component and acid component, in order to produce a polyamide-imide-based coating used in the present invention, for example, a substantially stoichiometric amount of diisocyanate component and acid component are copolymerized in a suitable organic solvent, A manufacturing method similar to that of the conventional polyamide-imide-based paint can be adopted.

More specifically, the diisocyanate component prepared by blending the aromatic diisocyanate compound represented by the general formula (I) in the above proportion is used together with a substantially equimolar amount of the acid component in a suitable organic solvent in an amount of 0 to 180. When the reaction is carried out at a temperature of ° C for 1 to 24 hours, a polyamideimide-based coating composition in which polyamideimide, which is a copolymer of a diisocyanate component containing the aromatic diisocyanate compound and an acid component, is dissolved or dispersed in an organic solvent is obtained. .

The polyamide-imide-based paint used in the present invention includes a polyamide-imide-based paint produced from an aromatic diisocyanate compound represented by the general formula (I) and an acid component as raw materials, and the above aromatic diisocyanate. It is also possible to use a mixture of a diisocyanate compound other than the compound and a polyamideimide-based coating material produced by using an acid component as a raw material. In this case, the mixing ratio of both coating materials is adjusted so that the ratio of the aromatic diisocyanate compound represented by the general formula (I) in the total diisocyanate component as a raw material is in the range of 10 to 65 mol%. do it.

If necessary, various additives such as pigments, dyes, inorganic or organic fillers, lubricants, etc. may be added to the polyamide-imide coating used in the present invention. The insulated wire of the present invention is manufactured by applying the above-mentioned polyamide-imide-based paint to the surface of the wire and baking it to form an insulating coating.

The thickness of the insulating coating is not particularly limited in the present invention, and it can be formed to the same thickness as the conventional one depending on the size of the electric wire and the like. Under the insulation film,
A base layer made of a material having good adhesion to the insulating coating and the electric wire may be provided. Examples of the underlayer include insulating films formed by coating and baking various conventionally known insulating coating materials such as polyurethane-based, polyester-based, polyesterimide-based, polyesteramideimide-based, polyamideimide-based, and polyimide-based. Among them, from the viewpoint of adhesion to electric wires and insulating coatings, mechanical strength of coatings, etc., it is formed by coating and baking a polyamideimide-based coating material containing diphenylmethane-4,4'-diisocyanate and trimellitic anhydride. The underlying layer is preferably used.

The film thickness of the underlayer is not particularly limited in the present invention either, but in consideration of the mechanical strength of the film, the ratio of the film thickness between the insulating film and the underlayer is in the range of 1/10 to 10/1. It is preferably within. A surface lubricating layer may be provided on the upper layer of the insulating coating in order to impart lubricity to the surface of the insulating coating.

As the surface lubricating layer, coating films of paraffins such as liquid paraffin and solid paraffin can be used, but in consideration of durability, various waxes, lubricants such as polyethylene, fluororesin and silicone resin are used as binder resins. A bound surface lubricating layer is more preferred.

[0026]

EXAMPLES The insulated wire of the present invention will be described below based on Examples and Comparative Examples. Example 1 In a flask equipped with a thermometer, a cooling tube, a calcium chloride filling tube, a stirrer, and a nitrogen blowing tube, while flowing 150 ml of nitrogen gas per minute from the nitrogen blowing tube, 10
8.6 g of trimellitic anhydride (hereinafter referred to as "TMA"), 11.9 g of naphthylene-1,5-diisocyanate (hereinafter referred to as "NDI"), and 127.3 g of diphenylmethane-4,4'-diisocyanate. (Hereinafter referred to as “MDI”). The ratio of NDI in all diisocyanates was 10 mol%.

Next, 637 g of N- was added to the flask.
Add methyl-2-pyrrolidone and stir with a stirrer 8
The mixture was heated at 0 ° C for 3 hours, further heated to 140 ° C over 3 hours, and then heated at 140 ° C for 1 hour. And 1
When the time has passed, stop heating and let it cool down to a concentration of 25%.
To obtain a polyamide-imide-based coating composition. This polyamide-imide-based coating material was applied onto a surface of a copper wire having a diameter of 1.0 mm and baked by a conventional method to prepare an insulated electric wire having an insulating coating film having a film thickness of 35 μm.

Example 2 NDI = 35.6 g and MDI = 99.0 were charged for NDI and MDI at the time of preparing a polyamide-imide type coating material.
g, the ratio of NDI in the total diisocyanate is 30
An insulated wire was produced in the same manner as in Example 1 except that the content was mol%.

Example 3 NDI = 59.4 g, MDI = 70.7
g, the ratio of NDI in all diisocyanates is 50
An insulated wire was produced in the same manner as in Example 1 except that the content was mol%.

COMPARATIVE EXAMPLE 1 NDI was not charged when preparing a polyamide-imide type coating, and M
Example 1 above, except that 141.4 g of DI was charged.
An insulated electric wire was produced in the same manner as. Comparative Example 2 NDI = 83.1 g, MDI = 42.4
g, the ratio of NDI in the total diisocyanate is 70
An insulated wire was produced in the same manner as in Example 1 except that the content was mol%.

Example 4 On a surface of a copper wire having a diameter of 1.0 mm, diphenylmethane-4,
Commercially available polyamide-imide-based coating containing 4'-diisocyanate and TMA (Hitachi Chemical Co., Ltd., product number HI-400)
Was applied and baked by a conventional method to form an underlayer having a film thickness of 17 μm. Next, the same polyamideimide-based coating material as that used in Example 3 was applied onto this underlayer by a conventional method and baked to form an insulating coating film having a thickness of 18 μm, thereby producing an insulated wire.

The following tests were conducted on the insulated wires of the above Examples and Comparative Examples. Appearance Evaluation The appearance of the insulated wire of each of the above Examples and Comparative Examples was visually observed. Elastic Modulus Measurement Copper wires were removed by etching from the insulated electric wires of Examples and Comparative Examples, and the remaining insulating coating (length 6 cm) was pulled using a tensile tester under the conditions of a chuck spacing of 3 cm and a pulling speed of 1 mm / min. Elastic modulus (kg / mm ² ) from the SS curve obtained by testing
I asked.

Flexibility Test A crack or peeling of the insulating coating was observed when a round bar having a diameter of 1 mm was applied to the insulated wires of Examples and Comparative Examples and the wire was bent in accordance with the outer shape of the round bar. , Those in which no abnormalities were observed were rated as good, and those in which abnormalities were observed were rated as bad. Rapidly pulling out the insulated electric wire of the rapid elongation test example and the comparative example from both ends,
After being rapidly stretched and cut, the floating amount (mm) of the coating film from the copper wire at the cut portion was measured.

Piano Wire Damage Load Measurement The insulated wires of the Examples and Comparative Examples are orthogonally overlapped with each other, and the piano wires are pulled out under a load of various weights, and the insulation coating is damaged. The load was recorded.
The above results are shown in Table 1.

[0035]

[Table 1]

From the results shown in Table 1 above, the insulated wire of Comparative Example 1 containing no NDI as a diisocyanate component has a low elastic modulus of the insulating coating, and the results of the piano wire damage load measurement show that the insulating coating is easily damaged. I knew that. on the other hand,
In the insulated wire of Comparative Example 2 in which the proportion of NDI exceeded 65 mol%, the elastic modulus of the insulating coating was remarkably low, and it was found from the results of piano wire damage load measurement that the insulating coating was very easily damaged. It was also found from the results of the flexibility test that the insulated wire of Comparative Example 2 had poor flexibility of the insulating coating, and from the results of the rapid elongation cutting test that the insulating coating was easily peeled off from the copper wire. Furthermore, the insulated wire of Comparative Example 2 also had a poor appearance.

On the other hand, all of the insulated wires of Examples 1 to 3 are not easily damaged and have excellent flexibility, and
It was found to have an insulating coating that was difficult to peel off from the copper wire. Further, from the results of each of the above-mentioned examples, the higher the NDI ratio, the higher the elastic modulus of the insulating coating and the more difficult the insulating coating is to be damaged, but the adhesiveness of the insulating coating is low in the NDI proportion. Moderately good, considering the balance of both characteristics, NDI
Of Examples 2 and 3 in which the ratio of
Was found to be particularly excellent.

Further, comparing the results of Example 3 and Example 4 in which the proportion of NDI is the same, Example 4 has a smaller floating amount of the insulating coating in the rapid elongation cutting test than Example 3, so that the base layer It was found that by forming the film, the adhesiveness of the coating can be further improved while maintaining other properties as they are.

[0039]

According to the insulated wire of the present invention, by introducing a naphthalene ring into the structure of polyamideimide to improve the elastic modulus of the insulating coating, it is excellent in flexibility and
An insulating coating that is not easily damaged can be formed. Therefore, the insulated wire of the present invention has excellent workability, and when it is used for winding a motor, for example, the insulating coating may be damaged in the winding process even if the winding amount to the core is increased more than ever before. Therefore, it is possible to meet the demand for a motor that is smaller, lighter and has better performance.

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Claims (6)

[Claims] 1. An insulated wire having an insulating coating formed by coating and baking a polyamideimide-based coating material containing at least a diisocyanate component and an acid component as raw materials,
The diisocyanate component as a raw material has the following general formula (I)
: [Chemical 1] [In the above formula, R ¹ and R ² are the same or different and each represents a hydrogen atom, an alkyl group, an alkoxy group or a halogen atom. Each of a and b is 0 to 2, and a + b = 2. ] The aromatic diisocyanate compound represented by 1
An insulated electric wire, characterized in that it is contained within a range of 0 to 65 mol%. 2. The insulated wire according to claim 1, wherein the content of the aromatic diisocyanate represented by the general formula (I) in the diisocyanate component as a raw material is 30 to 50 mol%. 3. A polyamideimide-based coating material produced from an aromatic diisocyanate represented by the general formula (I) and an acid component as raw materials, and a diisocyanate and an acid component other than the above as raw materials. The insulated wire according to claim 1, which is a mixture with the produced polyamide-imide-based paint. 4. The insulated wire according to claim 1, wherein the polyamide-imide-based coating material is produced from an aromatic diisocyanate represented by the general formula (I), a diisocyanate other than the above, and an acid component as raw materials. 5. A diphenylmethane-containing compound as a lower layer of the insulating coating.
The insulated wire according to claim 1, further comprising a base layer formed by applying and baking a polyamideimide-based coating material containing 4,4'-diisocyanate and trimellitic anhydride. 6. The insulated wire according to claim 1, further comprising a surface lubrication layer as an upper layer of the insulating coating.