JP3086376B2 - Manufacturing method of rectangular ultra-thin 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 a method for stably and continuously manufacturing a rectangular ultra-thin film insulated wire having excellent insulation properties and useful for miniaturization and weight reduction of electric equipment for a long period of time.

[0002]

2. Description of the Related Art The group to which the present inventors belong first has a flat rectangular conductor whose thickness at the flat portion is 3.0 μm or less and whose thickness at the corner portion is 1.1 times or more that of the flat portion. A rectangular ultra-thin insulated wire having an ultra-thin insulating layer has been proposed (JP-A-3-241609). This is to realize an ultra-thin insulating film as a whole while maintaining the required thickness of the insulating layer at the corners, thereby making it possible to reduce the weight and size of electric equipment and the like.

[0003] In the above, rolling an insulated round wire results in an insulating layer inferior in withstand voltage and heat shock resistance due to the occurrence of residual stress and cracks. Although it was proposed to perform the electrodeposition baking method which does not occur, when the flat ultra-thin film insulated wire was continuously manufactured in further research, the number of pinholes in the obtained insulating layer gradually increased. It was found that there was a problem in terms of long-term continuous manufacturability.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a method for producing a rectangular ultra-thin insulated wire capable of maintaining the initial production state for a long time without increasing the number of pinholes in the insulating layer even during long-term continuous production. The task is to obtain

[0005]

According to the present invention, an epoxy / acrylic water dispersion varnish having a turbidity of 3.0 or less based on a tan θ value is electrodeposited on a rectangular conductor, and the electrodeposited layer is baked. After processing, the flat portion of the rectangular conductor was 3.0 μm
A method for manufacturing a rectangular ultra-thin insulated wire, characterized in that an insulating layer having a thickness of not more than 1.1 times as thick as that of a flat portion at a corner portion is continuously formed. It is.

[0006]

Illustrative Embodiment The rectangular conductor has a thickness of 500
An ultrathin material having a thickness of not more than μm, especially 10 to 200 μm, is preferably used. In addition, the manufacturing method is such that the number of pinholes is one.
00 pieces / m or less, especially 70 pieces / m or less, especially 50 pieces / m
A continuous system of 20 hours or more, especially 50 hours or more, etc., is adopted while maintaining the following.

[0007]

According to the above-mentioned method using an epoxy-acrylic water dispersion varnish having a turbidity of 3.0 or less based on the tan θ value, an ultra-thin insulating layer having a small number of pinholes can be continuously and stably formed for a long time. Can be formed. Although the reason is unknown, the present inventors have found that in electrodeposition, a resin component having a small particle size is likely to be preferentially electrodeposited based on its large electrophoretic mobility. However, in the turbidity aqueous dispersion varnish of the present invention, the average particle size of the resin component is smaller than that of the conventional tanθ value of 5 to 7, and this is the reason. It is considered that an electrodeposition layer having few gaps that easily become pinholes is formed based on a resin component having a large particle diameter.

[0008]

The manufacturing method according to the present invention comprises the steps of: electrodepositing a water-dispersed epoxy-acrylic varnish having a turbidity of 3.0 or less based on a tan θ value on a rectangular conductor; 2. Baking treatment is performed on the flat portion of the rectangular conductor.
An insulating layer having a thickness of 0 μm or less and a thickness 1.1 times or more that of a flat portion at a corner portion is continuously formed to obtain a rectangular ultra-thin insulated wire. The rectangular ultra-thin insulated wire is illustrated in FIG. 1 is a rectangular conductor, 13
Is an insulating layer, 11 is its flat part, and 12 is its corner part.

The rectangular conductor may be made of any suitable material. The rectangular conductor which can be preferably used is made of a good conductive metal, and examples thereof include ordinary electrolytic copper, aluminum for electric use, copper alloy, copper clad aluminum, nickel-plated copper and the like.

Although the size of the rectangular conductor is arbitrary, the thickness of the rectangular conductor is not more than 50 in order to take advantage of the ultra-thin insulating layer according to the present invention.
An ultra-thin rectangular conductor of 0 μm or less, especially 10-200 μm, is advantageously used. The width may be appropriately determined according to the purpose of use, but is generally 0.1 to 5 mm, and the aspect ratio is generally about 1: 3 to 1: 100.

[0011] The insulating layer is attached to the rectangular conductor by an electrodeposition baking method of a water dispersion varnish. This makes it possible to form an ultrathin insulating layer while realizing the formation of a sufficiently thick insulating layer at the corners of the rectangular conductor. In the case of a solution type varnish, the coating film at the corners hardly flows out due to surface tension during baking, and the coating hardly remains. For example, even when the coating is applied to a flat portion with a thickness of 5 μm, the coating thickness at the corners is substantially 0 μm. And many pinholes are generated at the corners.

The water-dispersed varnish has a turbidity of tan.
3.0 or less based on the θ value, especially 0.01 to 2.95,
In particular, a 0.02-2.9 epoxy / acrylic aqueous dispersion varnish is used. As a result, the number of pinholes (JIS
C / 3003) 100 / m or less,
It is also possible to produce continuously for 20 hours or more, especially for 50 hours or more, while maintaining it at 70 pieces / m or less, especially 50 pieces / m or less. The turbidity is based on the tan θ value of the resin component in the aqueous dispersion varnish, and the tan θ value is
For example, a molecular weight distribution analyzer (Shimadzu / Kotaki, NT-
It can be checked in 3). It has been pointed out that there is a correlation between the tan θ value and the average particle diameter.

The type of the epoxy-acrylic water-dispersed varnish is not particularly limited, and a resin component composed of an appropriate epoxy-containing acrylic resin is dispersed in water using a stabilizer or the like, if necessary. Things and the like are used.
The dispersion medium may be a mixture of a hydrophilic solvent such as alcohol.

Examples of the above-mentioned epoxy group-containing acrylic resin include a component (a) composed of an acrylic monomer having a nitrile group and the like, a component (b) composed of an acrylic monomer having an epoxy group, and the like. Component (a) or / and / or component (c) comprising at least three types of unsaturated organic acids having one or more double bonds capable of reacting with the double bond in component (b). Polymers.

The acrylic monomer of the component (a) includes, for example, a compound of the general formula (a): CH ₂ ＣC (R ¹ ) R ² (where R ¹ is a hydrogen atom or an alkyl group, R ² is a nitrile group, It is an aldehyde group or a carboxy ester group.)
And the like.

The acrylic monomer of the component (b) includes, for example, a compound represented by the general formula (b): CH ₂ ＣC (R ³ ) R ⁴ (where R ³ and R ⁴ are a hydrogen atom, an alkyl group, an amide group, N
An alkylamide group, an alkylol group, a glycidyl ether group or a glycidyl ester group, and R ³ , R ⁴
At least one is a glycidyl ether group or a glycidyl ester group. And the like.

In preparing the copolymer, the component (a)
One or more of the components (b) and (c) can be used. Components that can be preferably used from the viewpoint of the heat resistance of the obtained insulating layer and the like are those represented by the aforementioned general formula (a),
The carbon number of R ¹ , R ² , R ³ , R ⁴ and the unsaturated organic acid of the component (c) in (b) is about 30 or less, preferably 15 or less.

Specific examples of the component (a) that can be preferably used include acrylonitrile, methacrylonitrile, methyl acrylate, ethyl acrylate, propyl acrylate,
Examples thereof include butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and acrolein. The component (a) which is particularly preferable from the viewpoint of the heat resistance and the like of the obtained insulating layer has a total carbon number of 15 or less.

Specific examples of the component (b) which can be preferably used include glycidyl acrylate, glycidyl methacrylate and allyl glycidyl ether.

Specific examples of the component (c) which can be preferably used include acrylic acid, methacrylic acid, crotonic acid, vinyl acetic acid, α-ethyl acrylic acid, β-methyl crotonic acid,
Tigulinic acid, 2-pentenoic acid, 2-hexenoic acid, 2-heptenoic acid, 2-octenoic acid, 10-undecenoic acid, 9-
Such as octadecenoic acid, cinnamic acid, atropic acid, α-benzylacrylic acid, methylatropic acid, 2,4-pentadienoic acid, 2,4-hexadienoic acid, 2,4-dodecanedienoic acid, and 9,12-octadecadienoic acid Dibasic acids such as monobasic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, muconic acid and dihydromuconic acid; and tribasic acids such as 1,2,4-butenetricarboxylic acid. Can be Particularly preferred component (c) is acrylic acid, methacrylic acid, crotonic acid, α-ethylacrylic acid, maleic acid, fumaric acid and the like.

The preparation of the above copolymer can be appropriately carried out by a known polymerization method such as an emulsion polymerization method, a solution polymerization method, a suspension polymerization method and the like. In this case, the use ratio of the component (a) is generally 1 to 20 mol, preferably 2 to 10 mol, particularly 4 to 6 mol per mol of the component (b). The use ratio of the component (c) is generally 0.01 to 0.2 mol, preferably 0.03 to 0.1 mol, per 1 mol based on the total of the components (a) and (b). .

The above-mentioned copolymer can also be prepared as a modified product of styrene or its derivative or diolefin. As the styrene derivative, the phenyl group of styrene is one or more of a nitrile group, a nitro group, a hydroxyl group, an amino group, a vinyl group, a phenyl group, a halogen atom, an alkyl group, an aralkyl group, and an N-alkylamino group. And substituted ones.

Examples of the halogen atom include chlorine and bromine. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. Examples of the aralkyl group include a benzyl group, α-phenyl ether and β-phenyl ether. Examples of the N-alkylamino group include N-methylamine, N-ethylamine, N-propylamine and the like.

Preferred styrene derivatives for modification include methylstyrene, ethylstyrene, divinylbenzene, chlorostyrene and the like. Preferred diolefins include butadiene, pentadiene and methyl-butadiene.

The preparation of the modified product can be carried out, for example, by copolymerizing one or more modifiers in the preparation of the above-mentioned copolymer. In this case, the use ratio of the modifier is preferably about 2 mol or less for styrene or its derivative and about 1 mol or less for diolefin per 1 mol of the component (a). If styrene or its derivative is used in an excessive proportion, the resulting insulating layer may have poor flexibility. If the proportion of the diolefin used is too large, the resulting copolymer may have a low softening temperature.

An epoxy-acrylic water-dispersed varnish that can be preferably used is an emulsion polymerization solution prepared by preparing an epoxy-acrylic copolymer by an emulsion polymerization method, or an epoxy-acrylic copolymer in water with a surfactant. The copolymer is preferably dispersed, and the degree of polymerization of the copolymer is preferably 2.0 or less from the viewpoint of obtaining a water-dispersed varnish having a turbidity based on the tan θ value of 3.0 or less.

The concentration of the epoxy-acrylic copolymer (resin component) in the water-dispersed varnish is generally 0.1 to 10% by weight, preferably 0.3 to 5% by weight. If the concentration is less than 0.1% by weight, pinholes are likely to occur, and if it exceeds 10% by weight, it becomes difficult to form a good ultrathin film.

The production of the rectangular ultra-thin insulated wire can be carried out by introducing a rectangular conductor into an epoxy-acrylic water-dispersed varnish and subjecting it to electrodeposition, and baking the electrodeposited layer. FIG. 1 shows an example of the manufacturing process.

In FIG. 1, the electrodeposition treatment is performed by placing D.C. in a cylindrical cathode 5 disposed in an electrodeposition bath 4 containing an epoxy-acrylic water dispersion varnish 3. This is performed while the rectangular conductor 1 connected to the anode side of the C power supply (not shown) is introduced and passed through the roll 2. By such an operation, an epoxy / acrylic resin component is deposited on the rectangular conductor with good uniformity in thickness based on the potential difference between the cathode and the rectangular conductor (anode).

The conditions for electrodeposition may be appropriately determined according to the thickness of the insulating layer to be formed. General conditions are described in C
Voltage 5-100V, especially 7-70V, electrodeposition time 0.01
~ 30 seconds, especially 0.03 ~ 15 seconds, varnish temperature 5 ~
40 ° C, especially 10-35 ° C. At that time, D. A. The C voltage can be superimposed.

The baking treatment may be carried out by immediately drying the electrodeposited layer after the electrodeposition treatment, or after the electrodeposition layer is treated with an organic solvent or the like before drying. In the example of FIG. 1, the treatment with such an organic solvent or the like is performed. The treatment with an organic solvent or the like aims at effectively fusing the resin component particles in the electrodeposition layer during the baking treatment to form a uniform film with less pinholes.

The treatment with an organic solvent or the like can be performed by an appropriate method such as immersing the rectangular conductor on which the electrodeposition layer is formed in the treatment liquid, or passing the treatment through the vapor or mist of the treatment liquid. In the example of FIG. 1, the rectangular conductor after the electrodeposition process is introduced into and passed through the bus 6 containing the processing liquid 7.

As the organic solvent, those which can swell, preferably dissolve, the resin component in the semi-cured state before drying and baking on the rectangular conductor, or in the electrodeposition layer before reaching the state. Is used.

Specific examples of the organic solvent include methanol, ethanol, propanol, ethylene glycol,
Monohydric or polyhydric alcohols such as glycerin, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether,
Cellosolves such as ethylene glycol diethyl ether, ethylene glycol dibutyl ether and ether glycol monophenyl ether; nitrogen-containing compounds such as N, N-dimethylformamide, N, N-dimethylacetamide and N-methyl-2-pyrrolidone; dimethyl sulfoxide And ionic solvents such as Organic solvents that can be preferably used include N, N-dimethylformamide, N, N-dimethylacetamide, and N-methyl-2-.
Pyrrolidone, dimethyl sulfoxide and the like.

In the above, in the present invention, at the outlet of the rectangular conductor in the electrodeposition bath and / or the processing solution bath,
For example, a wiping device such as an air wiper or a roller wiper may be provided to remove excess varnish or treatment liquid on the electrodeposition layer. By providing such a removing step, the stability of high-speed processing can be improved. That is, in a high-speed electrodeposition treatment or the like, the undeposited varnish attached to the electrodeposition layer may cause foaming in the baking process, which may hinder high-speed operation. Such a foaming phenomenon can be prevented, and high-speed work can be stably performed. Incidentally, it is possible to stably prevent the foaming phenomenon even at a high-speed operation of about 50 m / min or more.

The baking process of the electrodeposited layer is performed by subjecting the rectangular conductor provided with the electrodeposited layer to a drying step and a baking step. The drying and baking steps can take place via a series of heating devices or via separate heating treatments. In the example of FIG. 1, the latter method is adopted.
Denotes a drying device, and 9 denotes a baking furnace.

The drying step aims at removing water and the treatment liquid in the electrodeposition layer by evaporation. The drying conditions may be appropriately determined according to the presence or absence of the treatment with the treatment liquid, the type of the organic solvent in the treatment liquid, and the like. Generally, 60-300 ° C,
Drying is performed at a temperature of 100 to 250 ° C.

In the above-mentioned drying process or before the drying process, steam or steam mixed with air is used for the purpose of accelerating the evaporation of the liquid or bringing the resin component forming the electrodeposition layer into a semi-cured state or a completely cured state. A high-temperature treatment, for example, a treatment at a temperature of 200 to 500 ° C. may be added. In the case of such a high-temperature treatment process, the treatment with an organic solvent can be omitted.

The baking process aims at curing the resin component forming the electrodeposition layer. The baking temperature may be appropriately determined, and is generally 200 to 700 ° C, preferably 250 to 60 ° C.
0 ° C.

As described above, as shown in FIG. 2, the flat portion of the rectangular conductor 1 has a flat portion of 3.0 μm or less, especially 0.5 to 3.
A rectangular ultra-thin insulated wire having an insulating layer 13 having a thickness (11) of 0 μm, particularly 0.8 to 2.0 μm, and a thickness (12) of 1.1 times or more that of a flat portion at a corner portion. Are continuously formed and wound on the winder 10.

The rectangular ultra-thin insulated wire of the present invention can be used for various purposes as a coil winding in electric equipment and the like. In that case, in the rectangular ultra-thin insulated wire of the present invention, a self-fusion layer may be provided on the insulating layer for the purpose of facilitating coil winding work and the like. The self-fusing layer does not require an insulating function or a high degree of uniformity of the layer thickness. The self-fusion layer can be formed by an appropriate method such as a method of varnish squeezing with a felt or the like after dip coating the varnish.

[0042]

【Example】

Example 1 A copper rectangular conductor having a width of 600 μm and a thickness of 30 μm was introduced into an electrodeposition apparatus consisting of a vertical furnace at a linear velocity of 30 m / min with an anode side to form an electrodeposition layer. Electrodeposition conditions are diameter 6cm, length 3
Using a copper cylinder of 0 cm as the cathode, the distance between the electrodes was 3 cm, and the electrodeposition voltage was C15V, varnish temperature 20 ° C.

The epoxy / acrylic water dispersion varnish includes:
Acrylonitrile 5 mol, acrylic acid 1 mol, glycidyl methacrylate 0.3 mol, ion-exchanged water 760 g,
Put into a flask together with 7.5 g of sodium lauryl sulfate ester and 0.13 g of sodium persulfate, and place at room temperature under a nitrogen stream.
After stirring for 5-30 minutes, the mixture is brought to 50-60 ° C.
At room temperature for 3 hours. The turbidity was 1.0 based on the tan θ value.

Next, the rectangular conductor provided with the electrodeposition layer was replaced with N, N
A length 1 filled with saturated vapor of dimethylformamide
m, and dried at 200 ° C., and then baked at 400 ° C. to form an insulating layer having a thickness of 2 μm in a flat portion and an insulating layer having a thickness of 2.2 in a corner portion.
A rectangular ultra-thin insulated wire having a thickness of μm was continuously obtained for 50 hours.

Comparative Example 1 A rectangular prism was prepared in the same manner as in Example 1 except that an aqueous dispersion varnish consisting of an epoxy-acrylic resin obtained with a reaction time of 4 hours and having a turbidity of 6.0 based on the tan θ value was used. An ultra-thin insulated wire was obtained.

Evaluation Test The number of pinholes per meter in the insulating layer of the rectangular ultra-thin insulated wire obtained in Example 1 and Comparative Example was determined according to JIS C30.
03. In addition, the measurement object was each part of the production start part (0 hour), and 10 hours, 20 hours, and 50 hours (production termination part) from the production start.

The results are shown in Table 1. The value is 5
It means the range of the number of pinholes that appeared in the test results.

[Table 1]

[0048]

According to the present invention, it is possible to continuously and stably produce a rectangular ultra-thin film insulated wire for a long time while maintaining the initial production state in which the number of pinholes in the ultra-thin insulating layer is small. it can.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of an example of a manufacturing process.

FIG. 2 is an enlarged sectional view of an example of a rectangular ultra-thin insulated wire.

[Description of Signs] 1: Flat rectangular conductor 13: Insulating layer 11: Flat portion 12: Corner portion 4: Electrodeposited bus 3: Epoxy / acrylic water dispersion varnish 5: Cathode 8: Drying device 9: Baking furnace

────────────────────────────────────────────────── (5) References JP-A-3-241609 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01B 13/16 H01B 3/16-3 / 56 H01B 7/00-7/02

Claims (1)

(57) [Claims] 1. An epoxy-acrylic water-dispersed varnish having a turbidity of 3.0 or less based on a tan θ value is electrodeposited on a rectangular conductor, and the electrodeposited layer is baked. Characterized in that an insulating layer having a thickness of 3.0 μm or less in the flat portion and a thickness of 1.1 times or more in the corner portion is continuously formed at the corner portion. Manufacturing method.