JP3029172B2 - Insulated wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insulated wire, and more particularly to an insulated wire using a UV-crosslinked resin composition as a coating material.

[0002]

2. Description of the Related Art As a method of manufacturing a thin-film electric wire,
For example, as in the case of producing an enameled wire, a method of applying and curing a liquid material is well known. Examples of the liquid material include thermosetting, ultraviolet-curing, and electron beam-curing materials. Most of the enamel wires mentioned above use thermosetting materials (thermosetting varnishes). . This thermosetting varnish includes epoxy, silicone, polyurethane, polyester, polyamideimide,
There are polyimide type, polyesterimide type, formal type and the like. Among these, the enameled wire using a urethane-based thermosetting varnish has a feature not found in other enameled wires, in that it can be soldered as it is without peeling off the coating and further using no flux.

In recent years, with the miniaturization and weight reduction of computers, audios, automobiles, aircraft, artificial satellites, and the like, the wires and cables used for these have been reduced in diameter and diameter.
It tends to be thinner. Generally, such a tendency is dealt with by reducing the thickness of the coating of the electric wire / cable.

[0004] As one of the measures, there is an extrusion method. However, thinning by the extrusion method has the disadvantage that the thinner the coating, the more easily it is affected by the strain caused by the temperature difference between the coating material and the conductor, and the lower the elongation. For this reason, the above-mentioned disadvantages are prevented by preheating the conductor, but on the other hand, when the conductor becomes thinner, there is a disadvantage that the strength is reduced due to the preheating and the wire is easily broken due to the pressure of the material at the time of extrusion.

On the other hand, enameled wires are very effective if they have a small coating thickness and can be applied to such applications as electric wires.
However, the coating of enameled wires using the above-mentioned thermosetting materials requires a large number of safety steps because the coating and baking step usually needs to be repeated at least five times, and more than 50% of many of the materials are occupied by an organic solvent. There are problems that equipment is required, that coloring is not as easy as polyethylene and polyvinyl chloride due to baking, and that peelability is poor.

Accordingly, attention has been paid to a solvent-free and liquid ultraviolet-crosslinkable resin composition as a means for thin coating. This is used, for example, as a coating material for an optical fiber. In particular, urethane acrylate-based materials are often used. This UV-crosslinked resin composition is a radical polymerization, an ionic polymerization,
It is cured by a method such as cationic polymerization, and in particular, a method by radical polymerization is known.

The ultraviolet-crosslinkable resin composition is liquid and can be easily coated with a thin wall, has a high curing rate, and has a great effect on productivity. Further, since it is solventless, it has higher safety than a thermosetting varnish used for enameled wire, and an arbitrary film thickness can be obtained by one or several coatings. Further, since the resin composition can be a colorless and transparent resin composition, it has an advantage that coloring is easy as compared with a thermosetting varnish. In particular, urethane acrylate-based materials are excellent in toughness and flexibility, and are suitable as covering materials for electric wires.

[0008]

However, the conventional insulated wire using a UV-crosslinkable urethane acrylate-based material has an extremely high soldering temperature, so that a thin conductor may cause disconnection due to heat. However, the influence on the base material became a problem. In addition, resin residue (carbide) on the conductor
However, there is a problem that proper soldering cannot be performed because the solder is easily left.

Furthermore, a coating obtained by curing such a liquid resin composition by a polymerization cross-linking reaction often involves shrinkage during polymerization, and there has been a problem that cracks and cracks are liable to be generated when heat is applied during winding.

Therefore, an object of the present invention is to provide an insulated wire in which the soldering temperature of the ultraviolet-crosslinking resin composition is lowered so that no carbide of the resin remains on the conductor.
It is still another object of the present invention to provide an insulated wire that does not generate cracks or cracks due to heat applied to the winding.

[0011]

Means for Solving the Problems In order to solve the above-mentioned problems, the inventor of the present invention has conducted various studies on an ultraviolet-crosslinkable resin composition. As a result, the structure of the polyol component of the photopolymerizable oligomer in the ultraviolet cross-linking resin composition is a specific structure, and further, the functional group of the oligomer or the functional group of the monomer is a specific structure described below, so that soldering can be performed. The inventors have found that carbides sometimes do not adhere to the conductor, the soldering temperature can be lowered, and the generation of cracks and cracks due to the heat applied by winding can be prevented, and the present invention has been completed.

That is, the present invention relates to an insulated wire in which a cured coating layer of a urethane (meth) acrylate-based UV-crosslinked resin composition is provided on a conductor.
When the acrylate-based UV-crosslinked resin composition is a diisocyanate
And polyols and hydroxyalkyl (meth) acrylic
All functional groups produced from acrylates are methacryloyl groups
Oligomer, photopolymerizable monomer and photopolymerization initiator.
The polyol is an alkylene glycol and adipine
Polyester polyol and polycaprolact made of acid
At least one selected from ton polyols,
The photopolymerizable monomer is a monofunctional monomer having a methacryloyl group.
Provided is an insulated wire having an aromatic or cycloaliphatic terminal structure .

When the polyol portion is at least one selected from the group consisting of a polyester polyol composed of an alkylene glycol and adipic acid and a polycaprolactone polyol, the coating is easily peeled off by heat during soldering, so that solderability can be imparted. Further, generation of cracks and cracks in winding can be prevented. As the polyol, for example, a polyester polyol composed of an alkylene glycol such as ethylene glycol or propylene glycol and adipic acid, a polycaprolactone polyol,
As the polybasic acid in the polyester polyol, phthalic acid or the like may be contained in addition to adipic acid. Further, two or more polyols may be used in combination.

The molecular weight of the polyol is not particularly limited, but is preferably 3000 or less. If the amount is more than this, the curability and mechanical strength of the resin composition decrease.

The diisocyanate used in the production of the urethane (meth) acrylate oligomer is not particularly limited. Known diisocyanates such as methylene diisocyanate can be used. Preferably, hydrogenated diphenylmethane diisocyanate is good.

Examples of the hydroxyalkyl (meth) acrylate used include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate. Is preferably hydroxyalkyl methacrylate. This is because the crosslinked structure is broken in a short time to reduce the molecular weight, and the coating is easily peeled off from the conductor.

As described above, by making the functional group of the urethane acrylate oligomer a methacryloyl group, it becomes easy to lower the soldering temperature. Further, the thermal shock resistance is improved, and the generation of cracks due to the heat applied by winding can be suppressed.

It is to be noted that other oligomers may be used together according to the purpose, in an amount of about 30% or less of the total weight of the oligomers contained in the composition. The weight ratio of the oligomer to the composition is 30
% To 90% is desirable. If less than 30%, solderability,
It is difficult to maintain a balance of properties such as mechanical strength, flexibility, thermal shock resistance, and electrical properties.
This is because there is a problem that the material viscosity becomes extremely high and the material is inferior in handleability and applicability.

The photopolymerization initiator is not particularly limited, and any known photopolymerization initiator may be used. For example, there are acetophenone type, benzoin type, benzophenone type, thioxanthone type and the like. For acetophenones, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane Benzophenone-based benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl dimethyl ketal,
2.2-Dimethoxy-2-phenylacetophenone and the like. In addition, benzophenone-based compounds include benzophenone, methyl benzoylbenzoate, and 3,3′-dimethyl-4-methoxybenzophenone, and thioxanthone-based compounds include 2,4-diethylthioxanthone.
2,4-dichlorothiosaxanson and the like.

Further, in the present invention, it is desirable that the urethane (meth) acrylate-based UV-crosslinked resin composition further contains a monofunctional monomer having a methacryloyl group.

When a monofunctional monomer whose functional group is a methacryloyl group is used in combination with the photopolymerizable oligomer, the soldering temperature can be lowered more easily, the curing shrinkage rate can be suppressed, and cracking during winding can be prevented. And cracks can be suppressed. The monofunctional monomer having a methacryloyl group as a functional group is not particularly limited as long as the functional group has a methacryloyl group. Preferably, those having an aromatic or cyclic fatty terminal structure are preferred.

Examples of the above-mentioned monofunctional monomer having a specific terminal structure include phenyl methacrylate, phenoxyethyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, phenoxy polyethylene glycol methacrylate, phenoxy (poly) propylene glycol monomethacrylate, Hydroxy-3-phenoxypropyl methacrylate, detrahydrofurfuryl methacrylate, dicyclopentenyloxyethyl methacrylate, isobornyl methacrylate, dicyclopentenyl methacrylate, caprolactone-modified tetrahydrofurfuri methacrylate, ethylene oxide-modified phthalic methacrylate, and the like.
The methacrylic monofunctional monomers can be used alone or in combination of two or more.

The amount of the monofunctional methacrylic monomer having a specific terminal structure is not particularly limited and may be appropriately selected depending on the intended purpose. Is preferably selected so that the ratio of the photopolymerizable oligomer (prepolymer) to the total weight of the photopolymerizable oligomer (prepolymer) and the monofunctional monomer is 40 to 90% by weight. When the content of the photopolymerizable oligomer (prepolymer) is more than 90%, there is a problem that the viscosity is too high and coating workability is deteriorated.
If the amount is less than 0% by weight, there is a problem that the cured film is brittle, is inferior in flexibility, and is liable to crack or crack at the time of applying heat.

In addition, if desired, a monomer having a polyfunctional methacryloyl group, a monomer having an acryloyl group, a monomer having a functional group such as an allyl group or a vinyl group may be used in combination as long as the present invention is not hindered.

The metal constituting the conductor of the insulated wire of the present invention may be any of copper, aluminum, iron, silver, platinum and the like, and is an alloy of these, and an alloy obtained by further adding tin, zinc or the like. May be. In addition, even if the metal conductor is a single wire,
A stranded wire may be used, or a stranded wire may be collectively plated.

In the practice of the present invention, the resin composition may contain one or more of the following, if desired. That is, a photopolymerization auxiliary agent, an anti-adhesion agent, a thixotropic agent, a filler, a plasticizer, a non-reactive polymer, a colorant, a flame retardant, a flame retardant auxiliary, a softening inhibitor, a release agent, a desiccant, and a dispersant. Humectants, anti-settling agents, thickeners, anti-static agents, anti-static agents, fungicides, rodents, termites, matting agents, anti-blocking agents, anti-skinning agents and the like.

[0027]

Embodiments of the present invention will be described below in detail.
1 to 5 show a sectional structure of an insulated wire according to an embodiment of the present invention. The insulated wire in FIG. 1 includes a conductor 1 and an insulating layer (hereinafter simply referred to as an “insulating layer”) 2 made of a cured product of an ultraviolet-crosslinking resin composition that covers the conductor 1. The insulated wire in FIG. , A plurality of conductors 1,
An insulating layer 2 covering a plurality of conductors 1 collectively. The insulated wire in FIG. 3 includes a plurality of conductors 1 and a batch plating layer 4 covering the plurality of conductors 1 collectively.
And the insulating layer 2 covered from above the collective plating layer 4. The insulated wire in FIG. 4 has a plurality of conductors 1, an insulating layer 2 individually covering the plurality of conductors 1, and these are collectively covered. And a sheath 3. Further, the insulated wire in FIG. 5 is a combination of a plurality of conductors 1 and an insulating layer 2 covering the plurality of conductors 1 collectively, and a sheath 3 covering the whole of them.

The inventors blended the compositions shown in Table 1 to obtain nine types of insulated wires (Examples 1 to 5 and Comparative Examples 1 to 4) described below. At the same time, Table 1 shows the characteristics of the insulated wires of Examples 1 to 4 and Comparative Examples 1 and 2.

[Table 1]

Example 1 Urethane acrylate oligomer A comprising polyethylene glycol adipate diol / TDI (toluene diisocyanate) / HEMA (hydroxyethyl methacrylate) having a molecular weight of about 1000
80 parts by weight of phenoxyethyl methacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) and 100 parts by weight of photopolymerization initiator were added to 100 parts by weight.
An ultraviolet-crosslinking resin composition comprising 5.4 parts by weight of 2-dimethoxy-2-phenylacetophenone was added to an outer diameter of 0.13 m.
m, and then cured by passing through an ultraviolet irradiation furnace to obtain an insulated wire having an insulation thickness of 16 μm. Similarly, a tin-plated soft copper stranded wire (7 / 0.127) having an outer diameter of 0.38 mm was used, and the insulation thickness was 50 μm.
Insulated wire was obtained.

Example 2 Polyethylene glycol adipate diol having a molecular weight of about 1000 / H-MDI (methylene bis (4-cyclohexyl isocyanate)) / H
3. 100 parts by weight of urethane acrylate oligomer B composed of EA (hydroxyethyl acrylate), 60 parts by weight of phenoxyethyl methacrylate, and 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator.
8 parts by weight of an ultraviolet-crosslinkable resin composition having an outer diameter of 0.13
mm bare soft copper wire conductor (1 / 0.13)
It was cured through an ultraviolet irradiation furnace to obtain an insulated wire having an insulation thickness of 15 μm. Similarly, a tin-plated soft copper stranded wire (7 / 0.127) having an outer diameter of 0.38 mm was used, and the insulation thickness was 50 μm.
m of insulated wires were obtained.

Example 3 Polyethylene glycol adipate diol having a molecular weight of about 3000 / TDI / HEMA
An ultraviolet-crosslinkable resin composition comprising 40 parts by weight of isobornyl methacrylate and 4.2 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator was added to 100 parts by weight of a urethane acrylate oligomer C comprising After coating on a 13 mm bare soft copper wire conductor (1 / 0.13), it was cured through an ultraviolet irradiation furnace, and the insulation thickness was 15 μm.
m of insulated wires were obtained. Similarly, the outer diameter is 0.38 mm
Using a tin-plated soft copper stranded wire (7 / 0.127), an insulated wire having an insulation thickness of 50 μm was obtained.

Example 4 Polyethylene glycol adipate diol having a molecular weight of about 1000 / H-MDI / HE
An ultraviolet-crosslinking resin composition comprising 40 parts by weight of dicyclopentanyl methacrylate and 4.2 parts by weight of 2,2-dimethoxy-2-phenylacetophenone as a photopolymerization initiator was added to 100 parts by weight of urethane acrylate oligomer D composed of MA. 0.13 mm bare soft conductor (1 / 0.1
3) After being coated on top, it is cured through an ultraviolet irradiation furnace,
An insulated wire having an insulation thickness of 15 μm was obtained. Similarly, tin-plated soft copper stranded wire with an outer diameter of 0.38 mm (7 / 0.127)
Was used to obtain an insulated wire having an insulation thickness of 50 μm.

Example 5 40 parts by weight of dicyclopentanyl methacrylate and 100 parts by weight of a urethane acrylate oligomer E composed of polycaprolactone diol / H-MDI / HEMA having a molecular weight of about 2000 and 2,2-dimethoxy-photopolymerization initiator After coating an ultraviolet-crosslinking resin composition consisting of 4.2 parts by weight of 2-phenylacetophenone on a bare soft conductor (1 / 0.13) having an outer diameter of 0.13 mm, the resin was cured through an ultraviolet irradiation furnace and cured. 16μ
m of insulated wires were obtained. Similarly, the outer diameter is 0.38 mm
Using a tin-plated soft copper stranded wire (7 / 0.127), an insulated wire having an insulation thickness of 50 μm was obtained.

Comparative Example 1 100 parts by weight of a urethane acrylate oligomer F composed of polypropylene glycol / TDI / HEA having a molecular weight of about 1000 were added to 60 parts by weight of phenoxyethyl acrylate and 2,2-
After coating an ultraviolet-crosslinked resin composition comprising 4.8 parts by weight of dimethoxy-2-phenylacetophenone on a bare soft copper wire conductor (1 / 0.13) having an outer diameter of 0.13 mm, the resin was cured by passing through an ultraviolet irradiation furnace and insulated. A 15 μm thick insulated wire was obtained. Similarly, an insulated wire having an insulation thickness of 50 μm was obtained using a tin-plated soft copper stranded wire (7 / 0.127) having an outer diameter of 0.38 mm.

Comparative Example 2 100 parts by weight of a urethane acrylate oligomer F composed of polypropylene glycol / TDI / HEA having a molecular weight of about 1000 was added to 60 parts by weight of phenoxyethyl methacrylate and 2,2-
After coating an ultraviolet-crosslinked resin composition comprising 4.8 parts by weight of dimethoxy-2-phenylacetophenone on a bare soft copper wire conductor (1 / 0.13) having an outer diameter of 0.13 mm, the resin was cured by passing through an ultraviolet irradiation furnace and insulated. A 15 μm thick insulated wire was obtained. Similarly, an insulated wire having an insulation thickness of 50 μm was obtained using a tin-plated soft copper stranded wire (7 / 0.127) having an outer diameter of 0.38 mm.

Comparative Example 3 40 parts by weight of dicyclopentanyl methacrylate and 2,2-dimethoxy-2 as a photopolymerization initiator were added to 100 parts by weight of a urethane acrylate oligomer G composed of polycarbonate diol / H-MDI / HEMA having a molecular weight of about 1,000. -Phenylacetophenone 4.
2 parts by weight of an ultraviolet-crosslinkable resin composition having an outer diameter of 0.13
mm bare soft copper wire conductor (1 / 0.13)
It was cured through an ultraviolet irradiation furnace to obtain an insulated wire having an insulation thickness of 15 μm. Similarly, a tin-plated soft copper stranded wire (7 / 0.127) having an outer diameter of 0.38 mm was used, and the insulation thickness was 50 μm.
m of insulated wires were obtained.

Comparative Example 4 60 parts by weight of 1.6-hexadiol dimethacrylate and 2,2-part of a photopolymerization initiator were added to 100 parts by weight of a urethane acrylate oligomer G composed of polycarbonate diol / H-MDI / MEMA having a molecular weight of about 1000. After coating an ultraviolet-crosslinked resin composition comprising 4.8 parts by weight of dimethoxy-2-phenylacetophenone on a bare soft copper wire conductor (1 / 0.13) having an outer diameter of 0.13 mm, the resin was cured by passing through an ultraviolet irradiation furnace and insulated. 15μ thick
m of insulated wires were obtained. Similarly, the outer diameter is 0.38 mm
Using a tin-plated soft copper stranded wire (7 / 0.127), an insulated wire having an insulation thickness of 50 μm was obtained.

The characteristics of the insulated wires of Examples 1 to 5 and Comparative Examples 1 to 4 were examined below.

The evaluation method is as follows. 1. Solderability: A test piece having a length of about 15 cm is taken, and the tip of the test piece is placed on a solder (50Sn) set at an arbitrary temperature.
After immersing 0 mm for 1-2 seconds, take it out and immediately wipe it with a suitable cloth.
Except for mm, the temperature at which the solder was uniformly applied was examined. 2.20% elongation: 5 m of the produced insulated wire was taken, 20% of the entire length was stretched with the end fixed, and it was examined by pinhole test that no more film was formed. 3. Breakdown voltage: The prepared insulation wires were twisted, and the breakdown voltage between the wires was examined. The voltage was measured at a rate of 500 V / s at a rate as uniform as possible. 4. Surface hardness: A pencil lead specified in JIS S 6006 is cut into a blade shape at an angle of about 60 degrees, and this is pressed against the test piece at an angle of about 60 degrees with a force of about 4.9 N. The maximum hardness that does not break the coating when it was scratched once in the length direction with a core of a prescribed piece was examined. 5. Self-diameter winding: Winding was performed six times (n = 3) around a mandrel having the same diameter as the produced insulated wire, and the coating was observed under a microscope for cracks or cracks, and observed. 6. Winding heat: Winded 6 times (n = 3) around a mandrel having the same diameter as the produced insulated wire, 113 ° C, 121 ° C, 13
After heating at 6 ° C. for 1 hour, the film was taken out, and the number of cracks and cracks generated in the film was magnified with a microscope and observed.

As is clear from Table 1, in Examples 1 to 5 according to the present invention, the solderability was as good as 380 ° C., and no crack was generated in the coating of the twisted conductor due to the heat generated by the self-winding. Things have been obtained. In addition, it can be seen that when both the functional groups of the oligomer and the monomer are methacryloyl groups, the solderability is further improved, and the generation of cracks at the time of applying heat by winding is suppressed.

In Comparative Examples 1 to 4, when the functional groups of the oligomer and the monomer were all acryloyl groups, no solder was attached, and a twist using a composition containing an oligomer obtained without using an essential polyol was used. It can be seen that the conductor cracks during winding.

[0042]

As described above, in the insulated wire according to the present invention, the oligomer of the urethane (meth) acrylate-based UV-crosslinked resin composition used for forming the insulating coating layer comprises diisocyanate, polyol and hydroxyalkyl (meth).
Manufactured from acrylate, this polyol is at least one selected from polyester polyol and polycaprolactone polyol composed of alkylene glycol and adipic acid, and further has a specific structure of a functional group and a monomer of an oligomer, so that the soldering temperature is low. In addition to cracking, the cracks generated in the coating film during the application heat are greatly reduced, and no resin carbide remains on the conductor even when soldered.The functional group contains a monofunctional monomer consisting of a methacryloyl group. As a result, the lowering of the soldering temperature is further facilitated, and there is an effect that disconnection due to heat and the influence of heat on the base material can be suppressed.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a configuration of an insulated wire according to one embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of an insulated wire according to one embodiment of the present invention.

FIG. 3 is a sectional view showing a configuration of an insulated wire according to one embodiment of the present invention.

FIG. 4 is a sectional view showing a configuration of an insulated wire according to one embodiment of the present invention.

FIG. 5 is a cross-sectional view illustrating a configuration of an insulated wire according to one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Conductor (single wire or stranded wire) 2 Insulation layer 3 Sheath 4 Batch plating layer

Continued on the front page (72) Inventor Miyuki Suga 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture Inside Power Systems Research Laboratories, Hitachi, Ltd. (72) Inventor Norio Takahata 5-1-1 Hidaka-cho, Hitachi City, Ibaraki Prefecture No. 1 Nippon Electric Wire & Cable Co., Ltd. Power System Research Laboratories (72) Inventor Takanori Kasai 1135 Nakamura, Shibukawa-shi, Gunma Electrochemical Industry Co., Ltd. Shibukawa Plant (72) Inventor Junichi Kazami 1135 Nakamura, Shibukawa-shi, Gunma Electric (72) Inventor: Masayuki Kobayashi, 1135 Nakamura, Shibukawa-shi, Gunma, Japan Shibukawa Plant, Electrochemical Industry Co., Ltd. (56) Reference: JP-A-52-104780 (JP, A) JP-A-4-67515 (JP, A) JP-A-4-329215 (JP, A) JP-A-4-329216 (JP, A) JP-A-5-2923 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 7/02 H01B 3/30

Claims (1)

(57) [Claims] 1. An insulated wire having a cured coating layer of a urethane (meth) acrylate-based UV-crosslinked resin composition provided on a conductor, wherein the urethane (meth) acrylate-based UV-crosslinked resin composition comprises a diisocyanate, a polyol and a hydroxyalkyl Functional groups produced from (meth) acrylates
Oligomers and photopolymerizable monomers that are all methacryloyl groups
And a photopolymerization initiator, wherein the polyol is an alkylene
Polyester polyol consisting of glycol and adipic acid
And polycaprolactone polyols
At least one kind, wherein the photopolymerizable monomer is methacryloy.
Aromatic or cycloaliphatic terminal structure with monofunctional monomer of
An insulated wire characterized by having .