JP2002358828A - Coated electric wire and coil using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wire coated by a film with excellent heat resistant property and highly accurate thickness, and to provide a coil using the same. SOLUTION: The coated electric wire is formed by applying a film obtained by making the liquid obtained by dissolving aromatic polysulfonic resin, having repeating units expressed by the formula by 80 mol% or more per one molecule with reduced viscosity of 0.60-1.0 dl/g, in a solvent, flow and spread, and by evaporating the solvent. The solvent is at least one chosen from amide, sulfoxide, phenol, carbon halide, or cyclic ester, and the concentration of aromatic polysulfonic acid resin dissolved in the solvent ranges between 10 weight % and 50 weight %. The coil is obtained by using the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a covered electric wire and a coil using the same.

[0002]

2. Description of the Related Art Coated wires are used for coils used in industrial lances and motors. Since heat resistance is required for such an electric wire, a heat-resistant film such as polyethylene terephthalate, polyethylene naphthalate, or polyphenylene sulfide is coated on a conductive wire and used as an insulating layer. However, since the coated electric wire is processed into a coil shape and used, if there is variation in the thickness of the coated film, it cannot be uniformly wound into a coil shape, and there is a problem that the coil cannot be manufactured with high accuracy. . In order to manufacture coils with high precision, it is necessary to produce films with excellent thickness precision.However, polyethylene terephthalate, polyethylene naphthalate, and polyphenylene sulfide have the problem that it is difficult to produce films with excellent thickness precision. there were.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coated electric wire which is coated with a film having excellent heat resistance and excellent thickness accuracy, and a coil using the same.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to find a coated electric wire which does not have the above-mentioned problems, and as a result, have found that an aromatic polyether sulfone resin having a specific reduced viscosity is used. The inventor has found that a coated electric wire formed by coating a film manufactured by the casting method can be processed into a coil shape with high accuracy because the coated film has excellent thickness accuracy, and has completed the present invention. .

That is, the present invention provides an aromatic polysulfone resin containing 80 mol% or more of a repeating structural unit represented by the following structure per molecule and having a reduced viscosity of 0.60 to 1.0 dl / g as a solvent. It is intended to provide a coated electric wire characterized by being cast by dissolving a solution obtained by dissolving and coating a film obtained by evaporating a solvent. ... (I) (In the formula (I), R ₁ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a phenyl group or a halogen atom, and p is an integer of 0 to 4) Each R ₁ on the same or different nuclei may be different from each other, and each p may be different from each other.)

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. The aromatic polysulfone resin used in the present invention is a resin containing a repeating structural unit represented by the following general formula (I) in an amount of 80 mol% or more. Further, the aromatic polysulfone resin may be a resin containing at least one of a structure represented by the following general formula (II) or a structure represented by the following general formula (III); It may be a random copolymer or an alternating copolymer containing a repeating structural unit represented by the formula (III).

[0007] (I) (In the formula (I), R ₁ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a phenyl group or a halogen atom, and p is an integer of 0 to 4) Each R ₁ on the same or different nuclei may be different from each other, and each p may be different from each other.)

[0008] (II) (wherein, R ₁ represents the same as described above, p is an integer of 0 to 4. m and n each represent an average number of repeating structural units;
m and n are positive numbers from 0.1 to 100. Each R ₁ on the same or different nuclei may be different from each other. Each p may be different from each other. X has 1 to 20 carbon atoms
Represents an organic group, a carbonyl group, a divalent sulfur atom or a divalent oxygen atom. )

[0009] (III) (wherein, R ₁ represents the same as above, p is an integer of 0 to 4. q is an integer of 1 to 5. m and n indicate the average number of repeating structural units.) , M, and n are positive numbers from 0.1 to 100. Each R ₁ on the same or different nucleus may be different from each other, each p may be different from each other, and each q may be different from each other May be.)

Here, examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a t-butyl group and a cyclohexyl group. In addition, carbon number 2-10
Examples of the alkenyl group include, for example, ethynyl group, iso
-Propenyl group and the like. Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. As the organic group having 1 to 20 carbon atoms,
Examples thereof include a saturated aliphatic alkylene group such as an isopropylidene group, an ethylidene group, and a methylene group, an unsaturated aliphatic alkylene group such as an ethynylene group, and an aromatic alkylene group such as a xylylene group and a phenylmethylene group.

When the aromatic polysulfone resin used in the present invention has a structure represented by (II) or (III), (m / m + n) is at least 0.8. Also, (II
Q in the structure of I) is preferably 1 or 2,
More preferably, it is 2.

In the present invention, a resin having a structure comprising a repeating structural unit represented by (I) and a resin having a structure represented by (II) are preferably used, and more preferably a resin having a repeating structure represented by (I). A resin containing a unit structure is used. Above all, those in which all p's are 0, that is, a resin containing a structure composed of a repeating structural unit represented by the following formula is more preferable, and contains 80 mol% or more of the repeating structural unit represented by the following formula per one molecular chain. Resins are particularly preferred.

The reduced viscosity of the aromatic polysulfone resin used in the present invention is 0.6 to 1.0 dl / g, preferably 0.60 to 0.90 dl / g, and more preferably 0.70 to dl / g. 0.80 dl / g. 0.
If the resin is less than 6 dl / g, it is difficult to obtain a stable aromatic polysulfone resin varnish suitable for casting,
If it exceeds 1.0 dl / g, it is difficult to prepare a uniform solution, and filtration and defoaming become difficult, which causes a problem in the appearance of the cast film. Here, the reduced viscosity is 100c
After dissolving 1 g of aromatic polysulfone in m ³ of N, N-dimethylformamide, the viscosity of this solution was measured at 25 ° C. using an Ostwald viscometer.

As a method for producing the aromatic polysulfone resin used in the present invention, a known method can be employed. Further, a commercially available aromatic polysulfone resin may be used as it is. Commercially available aromatic polysulfone resins include, for example, those comprising the above structural unit (I) such as Sumika Excel PES7600P (trade name of Sumitomo Chemical Co., Ltd.) and the above structural units (I) such as Udelp-1700 (trade name of AMOCO). And (II). Further, the terminal structure is determined according to the production method of each resin, and is not particularly limited, and examples thereof include -Cl, -OH, -OR (R is an alkyl group) and the like.

As the solvent used for dissolving the aromatic polysulfone resin, for example, N-methyl-2-pyrrolidone,
Amides such as N, N-dimethylformamide and N, N-dimethylacetamide; sulfoxides such as dimethylsulfoxide; phenols such as cresol; halogenated carbons such as methylene chloride; cyclic esters such as γ-butyrolactone; And a good solvent for the aromatic polysulfone resin. These solvents may be used alone or in combination of two or more.

Further, a poor solvent or a non-solvent of the aromatic polysulfone resin such as hydrocarbons, ketones, esters, ethers and acetals may be added to the good solvent of the aromatic polysulfone resin. As hydrocarbons, cyclohexane, toluene, ketones, acetone and cyclopentanone, esters as ethyl acetate, and ether / acetals as methylal are preferably used. By adding these poor solvents or non-solvents, not only can the storage stability of the solution of the aromatic polysulfone resin be further improved,
Since the solution viscosity at the same concentration can be reduced as compared with the case where a good solvent is used alone, high solid differentiation can be achieved, which is very advantageous in practice.

The concentration of the aromatic polysulfone resin in the solution is preferably from 10% by weight to 50% by weight,
More preferably, it is 20% by weight to 40% by weight.
When the concentration is less than 10% by weight, the effective concentration is low, so that an orange peel due to convection is generated on the surface of the casting film in the initial stage of the heating and drying, and the surface smoothness tends to decrease. Due to this decrease in smoothness, there is a tendency that problems such as the coil being unable to be wound uniformly and variations in the size of the coil being generated. If the concentration exceeds 50% by weight, the stability tends to be poor such as gelation due to crystallization of the aromatic polysulfone resin during storage of the solution, and the solution has a high viscosity, so that the filterability and the defoaming property are high. Tends to be inferior. The method for producing the solution is not particularly limited,
The solvent may be added to the resin, or the resin may be added to the solvent. In order to increase the dissolution rate, it is preferable to use a powder as the form of the resin, but there is no particular limitation.

The solution may contain a leveling agent, a plasticizer, an inorganic filler, and the like, if necessary.
As the leveling agent, acryl-based, silicone-based, and fluorine-based agents can be used. As the plasticizer, those which have good compatibility with the aromatic polysulfone resin, do not cause phase separation or bleed-out, and do not cause coloring are preferable, for example, phthalic acid, phosphoric acid, adipic acid,
Examples thereof include citric acid type and glycolic acid type, and butylbenzyl phthalate, tricresyl phosphate, methylphthalylethyl glycolate and the like are preferably used. As the inorganic filler, for example, mica, silica, kaolin,
Examples include talc, alumina, calcium carbonate, lithium carbonate, barium sulfate, titanium oxide, magnesium oxide, and aluminum hydroxide.

Next, a method for producing a film using a solution containing an aromatic polysulfone resin will be described. The film is formed by casting a solution containing an aromatic polysulfone resin on a support to form a casting film containing a solvent (hereinafter, sometimes referred to as a casting step), and then removing the solvent from the casting film. It can be manufactured by evaporating (hereinafter, sometimes referred to as a drying step) (hereinafter, referred to as a drying step).
Solution casting method).

The casting step is a step of forming a casting film containing a solvent on a support. In this step, the solution of the aromatic polysulfone resin is cast on a support such as an endless band or a drum using a comma coater, lip coater, doctor blade coater, bar coater, roll coater or the like. The support is preferably made of a metal such as stainless steel subjected to mirror finishing, a resin film such as polyethylene terephthalate, glass, or the like, but is not limited thereto.

The drying step is a step of evaporating the solvent from the cast film to form an aromatic polysulfone resin film. The solvent is preferably evaporated by heating in order to improve the efficiency of the evaporation. The heating may be performed at a constant temperature, but it is preferable to change the heating over several steps from the viewpoint of economy and smoothness of the film surface.

The amount of the residual solvent in the dried film is preferably 5% by weight or less, more preferably 1% by weight.
Or less, more preferably 0.5% by weight or less. When the amount of the residual solvent is large, not only the glass transition temperature (Tg) of the aromatic polysulfone resin film is remarkably lowered, but when heat is applied in post-processing, dimensional change, curl, and moisture absorption tend to be caused. In addition, residual solvents also tend to adversely affect peripheral parts of the film in practical use.

The aromatic polysulfone resin as a raw material has a T
In order to efficiently produce a film obtained by using a solution containing an aromatic polysulfone resin having a Tg substantially equivalent to that of the aromatic polysulfone resin, a temperature higher than the Tg of the aromatic polysulfone resin after the drying step is required. It is preferred to heat with.

The formed aromatic polysulfone resin film is usually used after being peeled off from the support. The method of peeling is not particularly limited, but a long aromatic polysulfone resin film can be obtained by continuously peeling the film from the support.

[0025] The film thus obtained is free from streaks such as die lines and has excellent film thickness accuracy as compared with films produced by a melt extrusion method or an inflation molding method. I have. For this reason, when processing a conductive wire on which an insulating layer is formed by coating with the film into a coil, the coil can be wound uniformly and the coil size does not vary. The tensile elongation of the film produced by the solution casting method is preferably 20% or less, more preferably 15% or less, and even more preferably 10% or less. Since the tensile elongation of the film manufactured by the solution casting method is significantly lower than that of the film manufactured by the extrusion method, for example, when the film is non-uniformly expanded due to the tensile stress applied to the film when wound, and after being wound. The thickness unevenness of the insulating layer does not increase and the breakdown voltage does not vary.

The thickness accuracy of the film produced by the solution casting method is preferably within ± 10% of the average thickness, more preferably within ± 6%. ± 1 thickness accuracy
In the region of 0% or more, the insulation performance varies, the coil cannot be wound uniformly, and the size tends to vary. Further, it is preferable to use an aromatic polysulfone resin film which is slit in a tape shape. From the viewpoint of insulation performance and the size of the coil, the film thickness of the film is preferably 5 μm or more and 70 μm or less, more preferably 10 μm or more and 50 μm or less. 7 film thickness
If it exceeds 0 μm, the coil tends to be large although the insulation performance is excellent. When the film thickness is less than 5 μm, the coil is wound up smaller, but the insulation performance tends to decrease.

The insulated wire of the present invention and the coil using the same can be suitably used for applications such as industrial transformers and motors requiring heat resistance, such as electric motors.

[0028]

Hereinafter, the present invention will be described with reference to examples.
It goes without saying that the present invention is not limited by the examples. In addition, SUMIKAEXCEL PES4100G and SUMIKAEXCEL PES7600P, which are aromatic polysulfone resins used in Examples, are substantially composed of the following repeating structural units.

[Measurement of Film Thickness] The film thickness was measured using a foil thickness gauge model 497 manufactured by Ericssen. [Tensile Elongation] Measured in accordance with ASTM D882. [Dielectric breakdown voltage] Measured according to ASTM D149.

Example 1 Using a multi-test coater NCR230 (manufactured by Yasui Seiki Co., Ltd.) equipped with a knife coater with a clearance of 200 μm, trade name: Sumika Exexel PES760
0P (manufactured by Sumitomo Chemical Co., Ltd., polyether sulfone)
20% DMF solution with reduced viscosity 0.76 dl / g)
Cast on T film. At this time, the line speed was 0.5 m / min, and the temperature in the drying oven was 100 ° C. Further, the continuous film was cut into A4 size, dried in a ventilation oven at 200 ° C. for 2 hours, and peeled from the support to obtain a PES film for evaluation. When the physical properties of this film were evaluated, the Tg was 223 ° C., the average film thickness was 18 μm (minimum value 17 μm, maximum value 19 μm), and the dielectric breakdown voltage was 267 (KV / mm). I was

Comparative Example 1 Trade name: Sumika Excel 5200P (Sumitomo Chemical Co., Ltd.)
Manufactured by Polyethersulfone, reduced viscosity 0.52dl /
g) was dissolved in N, N-dimethylformamide to prepare a solution having a solid content of 25% by weight. This solution was cast on a glass plate using a bar coater (clearance 500 μm), and placed in a heating oven at 100 ° C. for 10 minutes. After that, when the surface state of the film was observed, orange peel was generated on the entire surface.

Comparative Example 2 Using GS65-25 (single axis, L / D = 25) manufactured by Ikegai Co., Ltd., the screw rotation speed was 15 rpm and the discharge rate was 10.9.
An extruded film having a trade name of Sumika Excel 4100G (manufactured by Sumitomo Chemical Co., Ltd., polyether sulfone, reduced viscosity 0.41 dl / g) was produced at kg / h and a take-up speed of 6.67 m / min. In this method, a film of 20 μm or less could not be produced stably,
A film having a thickness of 50 μm was produced. As a result of measuring the film thickness of this film, the average film thickness was 45 μm, and the minimum value was 4 μm.
The thickness was 3 μm, and the maximum value was 51 μm.

[0033]

[Table 1]

[0034]

According to the present invention, it is possible to provide a covered electric wire coated with a film having excellent heat resistance and excellent thickness accuracy, and a coil using the same.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) B29L 31:34 B29L 31:34 C08L 81:06 C08L 81:06 F term (Reference) 4F071 AA64 AF45 BB02 BC01 4F205 AA34 AC05 AG01 AH35 GA07 GB02 GC01 GC06 GE22 GN22 5G305 AA02 AB24 BA09 CA35 CD12 DA22 5G309 MA18

Claims (4)

[Claims] (1) a recurring structural unit represented by the following structure per molecule is contained in an amount of 80 mol% or more, and the reduced viscosity is 0.60
A coated electric wire, which is obtained by casting a solution obtained by dissolving an aromatic polysulfone resin having a concentration of ~ 1.0 dl / g in a solvent and evaporating the solvent to obtain a film. (I) (In the formula (I), R ₁ represents an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, a phenyl group or a halogen atom, and p is an integer of 0 to 4) Each R ₁ on the same or different nuclei may be different from each other, and each p may be different from each other.) 2. The coated electric wire according to claim 1, wherein the solvent is at least one solvent selected from amides, sulfoxides, phenols, carbon halides and cyclic esters. 3. The coated electric wire according to claim 1, wherein the solution is a solution having an aromatic polysulfone resin concentration of 10 to 50% by weight. 4. A coil obtained by using the covered electric wire according to claim 1.