JPH07282639A - Low dielectric constant enameled wire - Google Patents

Abstract

PURPOSE:To attain the decreasing of a relative dielectric constant and improving adhesiveness to and separation resistance from a conductor, by coating on the conductor with a specific ultraviolet hardened resin. CONSTITUTION:A conductor 1 is thick covered with an ultraviolet hardened resin 2 of a 2.8 or less effective relative dielectric constant of 1MHz compounding an acrylic denatured polybutadiene homopolymer or acrylic denatured fluororesin having CF2 in a molecule. Onto the resin 2, a general purpose use enamel coating 3 is applied to be baked.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low dielectric constant enameled wire. More specifically, the present invention mainly relates to a low dielectric constant enameled wire formed by coating an ultraviolet curable resin on a conductor.

[0002]

2. Description of the Related Art The demand for low-permittivity enameled wires is increasing with the sophistication of electronic equipment. For example, a wiring material and a wiring board that are more excellent in signal transmission are required.

A low dielectric constant enameled wire is used for such a high-speed signal-transmitting wiring material and wiring board.

However, the conventional general-purpose enameled wire cannot obtain a low dielectric constant.

That is, conventional general-purpose enameled wires such as formal wire, polyurethane enameled wire, polyester enameled wire, polyamideimide enameled wire, and polyimide enameled wire have a relative dielectric constant of 3.0 or more, and these requirements can be met. There wasn't.

On the other hand, polyethylene, polypropylene, polytetrafluoroethylene and the like are known to have a small relative dielectric constant. However, polyethylene, polypropylene, polytetrafluoroethylene and the like are typical thermoplastic resins, and cannot be practically used as an enameled wire in terms of adhesion with a conductor, peeling resistance, heat softening resistance, low hardness and the like.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object thereof is to solve the above-mentioned drawbacks of the prior art, and to improve the adhesion to a conductor and the peeling resistance. An object is to provide an enameled wire having a low dielectric constant which is excellent and has a small relative dielectric constant.

[0008]

The gist of the present invention is that a low dielectric constant enameled wire is obtained by coating a conductor with an ultraviolet curable resin having a relative dielectric constant of 2.8 or less at 1 MHz. It is in.

In the present invention, the ultraviolet curable resin coating material comprises an ultraviolet curable oligomer, a photopolymerizable monomer, a photoinitiator and the like.

Here, as the UV-curable oligomer, a material having a low effective relative dielectric constant, such as an acrylic-modified polybutadiene homopolymer, an UV-curable resin in which an acrylic-modified fluorine compound having CF ₂ in the molecule is blended, is used.

In the present invention, the low dielectric constant enameled wire may be a single layer as described above, but the coating layer of the ultraviolet curable resin may be composed of two or more layers, in which case the outermost layer is a hard ultraviolet ray having a pencil hardness of 4H or more. Cured resin, UV curable resin having a relative dielectric constant of 2.6 or less at 1 MHz, which accounts for 2/3 or more of the total UV curable resin coating layer, and the remaining inner layer is
An ultraviolet curable resin having a relative dielectric constant of 2.9 or less at MHz is used.

Further, the outer layer may be made of a resin for a general-purpose enameled wire.

In the present invention, the pencil hardness of the outermost layer is set to 4H or more because the coating hardness as an enamel wire tends to be lower than the material hardness due to the adhesion between the layers, so that the peeling when rubbing with a nail is caused. This is to avoid injury.

Further, in the present invention, the reason why the relative permittivity of the layer of 2/3 or more of the coating thickness of the coating material is 2.6 or less and the relative permittivity of the remaining layers is 2.9 or less is With other configurations, it becomes difficult to keep the relative permittivity of the enamel wire below the desired 2.8 or it is necessary to make the layer having a large relative permittivity, for example, the outer layer, extremely thin, which makes fabrication difficult. Is.

Generally, the effective relative permittivity of the insulator is preferably small from the viewpoint of reducing the propagation delay time, but the effective relative permittivity of the general-purpose enameled wire generally used is larger than 3.0, and thus lower than this. It is necessary.

[0016]

The function of the low dielectric constant enameled wire of the present invention is 2.
A low dielectric constant enameled wire having a small relative dielectric constant can be obtained by coating the conductor with an ultraviolet curable resin of 8 or less.

In the present invention, when the coating layer of the ultraviolet curable resin comprises two or more layers, the outermost layer has a pencil hardness of 4H.
By using the above hard resins, a harder outer layer can be obtained.

[0018]

EXAMPLES Next, examples of the low dielectric constant enameled wire of the present invention will be described together with comparative examples.

Example 1 A UV-curable coating material containing polybutadiene acrylate TEAI-3000 (Nippon Soda Co., Ltd.) having a relative dielectric constant of 2.6 or less at 1 MHz on a copper conductor having a diameter of 0.3 mm. After coating and irradiating it with ultraviolet light to cure it, polyurethane acrylate is made into an oligomer, and the hardness of the cured product is 4H or more and 1MH
An ultraviolet curable coating having an ε of z of 2.9 or less was applied and irradiated with ultraviolet rays to obtain an electric wire having a two-layer structure.

Here, the coating thickness of the inner layer was 50 μm and the coating thickness of the outer layer was 10 μm.

(Example 2) 1,2 polybutadiene homopolymer having both ends modified with acrylic acid and hydrogenated unsaturated double bonds, isobornyl acrylate and benzyl dimethyl ketal as a photopolymerization initiator, and a cured product of 1 MHz The coating material having a relative dielectric constant of 2.55 is coated on a copper conductor of φ0.3 mm with a die to a coating thickness of 50 μm, and then is irradiated with ultraviolet rays using a metal halide lamp (I-Graphics). Then this was cured. After that, a layer made of polyimide and having a pencil hardness of 4H or more was formed on the coated wire so as to have a coating thickness of 10 μm based on a usual method for producing an enamel wire, to obtain a two-layer structure enamel wire.

(Example 3) The same structure as in Example 2 was adopted except that the outer layer was made of polyester and had a pencil hardness of 4H or more.

Comparative Example 1 The same structure as in Example 1 was used except that the cured product of the polybutadiene acrylate compound of the inner layer in Example 1 was set to 2.8.

Comparative Example 2 The same structure as in Example 1 was adopted except that the pencil hardness of the outer layer urethane acrylate when cured was HB.

Comparative Example 3 The same structure as in Example 1 was used except that the relative dielectric constant at 1 MHz of the cured product of urethane acrylate of the outer layer was 3.3.

Comparative Example 4 In Example 1, the coating thickness of the inner layer was 30 μm and the coating thickness of the outer layer was 30 μm. (Comparative Example 5) Using the polyimide varnish used in Example 2, a coating film having a coating thickness of 60 µm was formed on a copper conductor having a diameter of 0.3 mm to obtain an enamel wire.

(Comparative Example 6) A polyester varnish having the same structure as in Comparative Example 4 was used.

(Comparative Example 7) Using the ultraviolet curable coating material used in Example 2, a coated wire having a 60 µm thick ultraviolet curable layer on a φ0.3 mm copper conductor was prepared.

(Comparative Example 8) After forming the inner layer in the same manner as in Example 2, an ultraviolet curable material having a pencil hardness of HB of the cured product is applied on the outer periphery of the inner layer so as to have a coating thickness of 10 μm, and a metal halide lamp is obtained. It was used and cured to obtain a two-layer enamel wire.

(Comparative Example 9) An insulated wire having the same structure as in Example 2 except that the relative permittivity of the ultraviolet curable layer was 2.7 was obtained.

(Embodiment 10) The same constitution as in Embodiment 2 was adopted except that the relative permittivity of the ultraviolet curable layer was changed to 2.96.

(Evaluation Test) For the evaluation, a relative dielectric constant at 1 MHz, adhesion and a peeling test with a nail were performed. The relative dielectric constant was 2.8 or less, and the adhesion and peeling tests were those without peeling and scratches.

Table 1 shows the results of these evaluation tests.

[0034]

[Table 1]

As can be seen from Table 1, in Comparative Examples 1, 3 and 4, the relative dielectric constant was large and the samples were rejected. Further, in Comparative Example 2, when the film was rubbed with a nail, the coating film was peeled off and dielectric breakdown occurred.

In Comparative Examples 5 and 6, the relative dielectric constant is 3.
It was rejected by more than 0. Further, in Comparative Examples 7 and 8, when scratched with a nail, the coating was scratched and dielectric breakdown occurred. In Comparative Examples 9 and 10, the relative dielectric constant was larger than the set value (≦ 2.8), and the outer layer had to be made thinner in order to obtain the desired dielectric constant. In this case, the appearance was rough due to uneven coating. .

On the other hand, Examples 1 to 3 exhibited a small relative dielectric constant and excellent adhesion and peeling resistance.

In this embodiment, an example of a single layer having only an inner layer is not shown, but the enamel wire having only this single layer has a much smaller relative dielectric constant and is an excellent enamel wire having a relative dielectric constant.

[0039]

The low-dielectric-constant enameled wire of the present invention has excellent adhesion and peeling resistance, and has an extremely small effective relative dielectric constant, and is useful as a high-speed signal-transmitting enameled wire.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the low dielectric constant enameled wire of the present invention.

[Explanation of symbols]

 1 conductor 2 UV curable resin layer 3 outer layer

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Kenji Asano 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Power Systems Co., Ltd.

Claims (6)

[Claims] 1. A low dielectric constant enameled wire comprising a conductor coated with an ultraviolet curable resin having an effective relative dielectric constant at 1 MHz of 2.8 or less. 2. The low dielectric constant enameled wire according to claim 1, wherein the ultraviolet curable resin is an acrylic modified polybutadiene homopolymer. 3. The low dielectric constant enameled wire according to claim 1, wherein the ultraviolet curable resin contains an acrylic modified fluorine compound having CF ₂ in its molecule. 4. A coating layer of UV curable resin is composed of two or more layers, the outermost layer of which is a hard UV curable resin having a pencil hardness of 4H or more, and the inner layer which occupies 2/3 or more of the total UV curable resin coating layer is effective at 1 MHz. A low dielectric constant enameled wire, characterized in that the relative dielectric constant is 2.6 or less of ultraviolet curable resin, and the remaining inner layer is an ultraviolet curable resin having an effective relative dielectric constant of 2.9 or less at 1 MHz. 5. An ultraviolet curable resin having an effective relative permittivity at 1 MHz of 2.8 or less is repellently coated directly on the conductor, and a coating / baking layer of a general-purpose enamel paint is provided on the ultraviolet curable resin layer. A low-dielectric-constant enameled wire characterized in that 6. The general-purpose enamel coating baking layer is one selected from formal resin, polyurethane resin, polyester resin, polyesterimide resin, polyamideimide resin, and polyimide resin.
Low-dielectric constant enameled wire described.