JP2017188243A - Insulation wire and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation wire excellent in adhesiveness to a conductor of a resin insulation layer and external damage resistance.SOLUTION: An insulation wire 10 has a conductor 11 and a resin insulation layer 12 formed from a polyamide-imide resin coating an outer peripheral surface thereof. Exposure rate of the conductor 11 at a part having a predetermined width with length from a breaking point of 4 mm on a side surface view after the insulation wire is subjected to a drastic elongation test based on JISC3216-3:2011 is 7% or less. Young modulus of the resin insulation layer 12 calculated by a microhardness tester is 9.0×10N/mmor more.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to an insulated wire and a method for manufacturing the same.

  It is known to manufacture an insulated wire by covering a conductive wire with a resin insulating layer. Patent Documents 1 to 3 disclose a method of manufacturing an insulated wire in which a conductive wire is dipped in a paint in which a resin is dissolved in a solvent and pulled up, and then the paint is baked on the conductive wire to form a resin insulating layer. Patent Documents 1 and 2 disclose that the resin insulating layer is formed of a polyamideimide resin.

JP-A-5-242738 JP 59-35319 A JP 2000-169918 A

  The subject of this invention is providing the insulated wire which is excellent in the adhesiveness of the resin insulation layer to a conducting wire, and excellent in damage resistance, and its manufacturing method.

The insulated wire of the present invention comprises a conducting wire and a resin insulating layer formed of a polyamide-imide resin covering the outer peripheral surface of the conducting wire, and the insulated wire is rapidly stretched based on JISC3216-3: 2011. The exposure rate of the conducting wire in a portion having a predetermined width of 4 mm from the breaking point in a side view after the test is 7% or less, and the Young's modulus of the resin insulating layer determined by a microhardness meter is 9.0. × 10 ³ N / mm ² or more.

  The method for producing an insulated wire according to the present invention is to coat the outer peripheral surface of the conducting wire with a resin insulation layer by continuously conducting the electrode through an electrodeposition coating composition of an O / W dispersion and applying the electrodeposition. The electrodeposition coating composition contains a polyamideimide resin, an aprotic polar solvent, and water, and has a solid content concentration of 2 to 4% by mass, and contains the aprotic polar solvent. The amount is 10 to 20% by mass.

According to the present invention, since the exposure rate of the conducting wire after the rapid extension test is 7% or less and the Young's modulus of the resin insulating layer is 9.0 × 10 ³ N / mm ² or more, the resin to the conducting wire In addition to the excellent adhesion of the insulating layer, it is possible to obtain excellent trauma resistance.

It is a perspective view of the insulated wire which concerns on embodiment. It is a perspective view of the other insulated wire which concerns on embodiment. It is a figure which shows the process order of the manufacturing method of an insulated wire. It is explanatory drawing which shows the measuring method of a coil dielectric breakdown voltage value. It is a graph which shows the relationship between the temperature in the thermomechanical analysis (TMA) of a resin insulating layer, and the displacement amount of a probe. It is a photograph for demonstrating the measuring method of the exposure rate of a flat conducting wire. It is a graph which shows the relationship between the solid content density | concentration of an electrodeposition coating composition, and the thickness of each part of a resin insulation layer (solid content concentration of 6 mass% of an original electrodeposition coating composition). It is a graph which shows the relationship between the solid content density | concentration of an electrodeposition coating composition, and the thickness of each part of a resin insulation layer (solid content concentration of 10 mass% of an original electrodeposition coating composition). It is a graph which shows the relationship between the solid content density | concentration of an electrodeposition coating composition, and a dielectric breakdown voltage. It is a graph which shows the relationship between content of the aprotic polar solvent of an electrodeposition coating composition, and a film dent and the number of pinholes. It is a graph which shows the relationship between content of the basic neutralizing agent of an electrodeposition coating composition, a film dent, and the number of pinholes (linear speed 30m / min). It is a graph which shows the relationship between content of the basic neutralizing agent of an electrodeposition coating composition, a film dent, and the number of pinholes (linear velocity 25m / min). It is a graph which shows the relationship between content of the basic neutralizing agent of an electrodeposition coating composition, a film dent, and the number of pinholes (linear speed 35m / min).

  Hereinafter, embodiments will be described in detail.

  1A and 1B show an insulated wire 10 according to an embodiment. The insulated wire 10 according to the embodiment has a flat rectangular shape in which the upper and lower surfaces and both side surfaces are formed flat as shown in FIG. 1A, and the upper and lower surfaces as shown in FIG. 1B. The cross-sectional shape formed in the curved surface which is formed in the flat surface and the both side surfaces bulged outside may be either flat. The insulated wire 10 according to these embodiments is used for, for example, a coil, a noise filter, an inductor, a reactor, and the like mounted on an electronic substrate in the field of electric / electronic equipment.

  The insulated wire 10 according to the embodiment includes a flat conducting wire 11 having a flat cross-sectional shape and a resin insulating layer 12 covering the outer peripheral surface thereof.

  The flat conducting wire 11 is made of, for example, high purity copper having a purity of 4N or higher. The flat conductor 11 has a thickness of, for example, 0.02 to 1 mm, and a width of, for example, 0.2 to 4.0 mm.

  The resin insulating layer 12 is made of a polyamideimide resin. The resin insulating layer 12 is preferably composed of a single treatment layer. The thickness of the resin insulating layer 12 is preferably 1.5 μm or more, more preferably 3 μm or more, and preferably 10 μm or less, more preferably 5 μm or less. In the thickness of the resin insulating layer 12, the long side center corresponding part 12a and the long side end corresponding part 12b are usually relatively thick, and then the corner corresponding part 12c and the short side corresponding part 12d are relatively thin. The difference in thickness between these portions is preferably small, and the thickness uniformity of the resin insulating layer 12 is preferably high. The difference in thickness between these parts is preferably 3 μm or less, more preferably 2 μm or less.

The Young's modulus of the resin insulating layer 12 is 9.0 × 10 ³ N / mm ² or more, and is preferably 1.0 × 10 ⁴ N / mm ² or more from the viewpoint of obtaining excellent damage resistance. The Young's modulus of the resin insulating layer 12 is obtained by a micro hardness meter. Specifically, while controlling the indentation load, the resin insulating layer 12 is indented with a cone-shaped (for example, triangular pyramid or cone-shaped) indenter, and a function of the indentation depth against the indentation load is plotted. Calculate Young's modulus. Note that the conical spreading angles are, for example, 100 ° and 115 °.

  The number of coating recesses in the resin insulating layer 12 is preferably small, and is preferably 5 or less, more preferably 1 or less, and most preferably 0 per 1.5 m. The number of pinholes in the resin insulating layer 12 is also preferably small, preferably 10 or less per 5 m, more preferably 5 or less, and most preferably 0.

  The insulated wire 10 according to the embodiment has a predetermined width of 4 mm from the breaking point in a side view after a rapid extension test based on JIS C3216-3: 2011 “winding test method—part 3: mechanical properties” From the viewpoint of obtaining excellent adhesion of the resin insulation layer 12 to the flat conducting wire 11, the exposure rate of the flat conducting wire 11 in the portion (which depends on the outer diameter of the insulated wire 10, for example, 1 mm in the center) is 7% or less. , Preferably 5% or less, more preferably 3% or less, and most preferably 0%. The “rapid extension test” is defined in “5.3 Rapid extension test” of “5 Flexibility and adhesion” of JIS C3216-3: 2011. Further, the exposure rate is obtained by image processing of a side image using a microscope at the tip of the broken insulated wire 10. Specifically, the side image is simply binarized into a white area and a colored area, and the area ratio of the white area is used as the exposure rate of the flat wire 11. The threshold for simple binarization is set so that the rectangular conducting wire 11 turns white after confirming the side image. Further, when it is difficult to separate the color tone of the flat conducting wire 11 and the resin insulating layer 12 in the side image, the exposed area of the flat conducting wire 11 in the side image may be colored white.

  The dielectric breakdown voltage of the insulated wire 10 according to the embodiment is preferably 0.3 V or higher, more preferably 0.5 V or higher. This dielectric breakdown voltage is measured by the method described in Test Evaluation 2 of Examples described later.

  In thermomechanical analysis (TMA) in which a spatula or needle probe is pressed against the resin insulation layer 12 of the insulated wire 10 according to the embodiment with a force of 25 mN and the temperature is increased at a rate of 10 ° C./min, the temperature and the displacement of the probe When the temperature at the expansion start point of the displacement amount in relation to the amount is the softening start temperature, the softening start temperature is preferably 250 ° C. or higher, more preferably 260 ° C. or higher, and preferably 400 ° C. or lower, more Preferably it is 350 degrees C or less. The softening start temperature is obtained as an intersection of a substantially horizontal straight line in the low temperature region and a displacement amount expansion line in the temperature region where the displacement amount expands based on a graph showing the relationship between the temperature and the probe displacement amount. it can. The softening start temperature can also be obtained by differentiating the curve of the relationship between temperature and probe displacement.

According to the insulated wire 10 according to the embodiment having the above configuration, the exposure rate of the flat wire 11 after the rapid extension test is 7% or less, and the Young's modulus of the resin insulating layer 12 is 9.0 × 10 ³ N. Since it is / mm ² or more, it is possible to obtain excellent damage resistance as well as excellent adhesion of the resin insulating layer 12 to the flat conductive wire 11.

  Next, the manufacturing method of the insulated wire 10 which concerns on embodiment is demonstrated.

  The manufacturing method of the insulated wire 10 according to the embodiment includes a wire drawing process, a cold working process, an annealing process, an oil removing process, and an electrodeposition coating process, as shown in FIG. In addition, these processes may perform each process by a batch type, and may perform all the processes by a continuous type. Furthermore, for example, a wire drawing process and a cold working process are performed by a continuous type. After performing, only an annealing process may be performed by a batch type, and it may carry out combining a batch type and a continuous type like the case where the oil removal process and electrodeposition coating process after that are performed by a continuous type.

<Wire drawing process>
In the wire drawing process, the rough drawn wire as a bus bar is reduced in diameter and drawn into a round wire having a circular cross section. In general, the drawing process includes a process of passing a rough drawing wire through a drawing die. The outer diameter of the rough drawn wire is, for example, 8.0 mm, and the outer diameter of the round wire after drawing is, for example, 0.05 to 0.2 mm. Note that the wire drawing is usually performed in multiple stages. For example, first, a rough drawing wire having an outer diameter of 8.0 mm is drawn so that the outer diameter is 2.6 to 3.2 mm, and then 0.6 to The wire is drawn to 0.8 mm, and further drawn to 0.05 to 0.2 mm.

<Cold working process>
In the cold working process, the round wire drawn in the drawing process is cold worked into a flat conducting wire 11 including a pair of flat surfaces parallel to the outer peripheral surface. Examples of cold working include rolling that passes a round wire between rollers of a rolling mill, processing that passes a round wire through a die, and the like. When manufacturing the insulated electric wire 10 having a flat cross-sectional shape in which the upper and lower surfaces and both side surfaces are formed flat as shown in FIG. 1A, the round wire is rolled in each of the thickness direction and the width direction. A flat conducting wire 11 having a similar cross-sectional shape can be obtained. In addition, when manufacturing an insulated electric wire 10 having a flat cross section formed on a curved surface in which the upper and lower surfaces are formed as flat surfaces and both side surfaces bulge outward as shown in FIG. The flat conducting wire 11 having the same cross-sectional shape can be obtained by rolling.

<Annealing process>
In the annealing step, physical properties such as crystal grain size and 0.2% proof stress of the metal forming the flat wire 11 are adjusted by heat treatment. The heat treatment in this annealing process is preferably performed batchwise from the viewpoint of uniforming the characteristics in the length direction. In that case, the bobbin around which the flat wire 11 is wound after the cold working process is put into a heat treatment furnace. After that, it is preferable to raise the temperature in the furnace to a predetermined holding temperature at a predetermined temperature rising rate, hold the predetermined holding time at the holding temperature, and then lower the temperature in the furnace at a predetermined temperature lowering rate. Here, the temperature rising rate is, for example, 20 to 2000 ° C./h. The holding temperature (annealing temperature) is, for example, 150 to 1000 ° C. The holding time (annealing time) is, for example, 1 second to 100 hours. The cooling rate is, for example, 10 to 2000 ° C./h. Moreover, when performing heat processing by a continuous type, heat processing conditions are the annealing temperature of 500-900 degreeC, and annealing time 1-60 seconds, for example. The heat treatment is preferably performed in an inert gas atmosphere such as nitrogen gas. In addition, when it is a small diameter, the heat processing by this annealing process is not necessarily required.

<Oil removal process>
In the oil removal step, the oil attached to the outer peripheral surface of the flat conducting wire 11 is removed by washing. Cleaning in this oil removal step is performed by, for example, immersing and pulling up the flat conducting wire 11 in the cleaning liquid and then spraying an inert gas such as nitrogen gas to scatter the cleaning liquid adhering to the outer peripheral surface of the flat conducting wire 11. be able to. Here, examples of the cleaning liquid include water (warm water), an organic solvent, and the like. When the cleaning liquid is water, the water temperature is, for example, 10 to 60 ° C. The cleaning liquid may contain a detergent.

<Electrodeposition painting process>
In the electrodeposition coating step, the outer peripheral surface of the flat conducting wire 11 is covered with the resin insulating layer 12 by electrodeposition coating using the electrodeposition coating composition. Specifically, the rectangular conductive wire 11 is continuously passed through the electrodeposition coating composition, and a voltage is applied to the electrodeposition coating composition using the flat conductive wire 11 as one electrode, whereby the electrodeposition coating is applied to the outer peripheral surface of the rectangular conductive wire 11. The resin insulation layer 12 is formed by depositing the composition and baking the electrodeposition coating composition deposited on the outer peripheral surface of the flat wire 11 through a baking furnace.

  Here, the electrodeposition coating composition used for electrodeposition coating includes a polyamideimide resin, an aprotic polar solvent, a basic neutralizing agent, a colorant, and water, and the polyamideimide resin particles are water. O / W type dispersion dispersed in The electrodeposition coating composition may be either an anionic type or a cationic type.

  The number average molecular weight of the polyamideimide resin is, for example, 5000 to 75000. The number average molecular weight of the polyamideimide resin is measured by gel permeation chromatography (GPC) using a standard polystyrene calibration curve.

  The acid value of the polyamideimide resin is, for example, 10 to 50 mgKOH / g. The acid value of the polyamide-imide resin is measured based on JISK5601-2-1: 1999 “Paint component test method-Part 2: Component analysis in solvent-soluble materials—Section 1: Acid value (titration method)”. The

  “Aprotic polar solvent” is a polar organic solvent excluding alcohol. Since the aprotic polar solvent has polarity, it has a high affinity for water, and when mixed with water, the aprotic polar solvent dissolves without phase separation and becomes a uniform single phase. The aprotic polar solvent contained in the electrodeposition coating composition needs to be a good solvent for the polyamideimide resin. The “good solvent for polyamideimide resin” refers to a solvent having high solubility in polyamideimide resin, specifically, a solvent in which the amount of polyamideimide resin dissolved in 1 kg of solvent at 25 ° C. is 100 g or more. Examples of such aprotic polar solvents include N-methyl-2-pyrrolidone (hereinafter referred to as “NMP”), dimethylformamide (hereinafter referred to as “DMF”), 1,3-dimethyl-2-imidazolidinone ( Hereinafter, it is preferably referred to as “DMI”), dimethylacetamide, γ-butyrolactone, dimethyl sulfoxide, sulfolane, or cyclohexanone. More preferably, the aprotic polar solvent contains NMP or DMF in addition to NMP.

  The content of the aprotic polar solvent in the electrodeposition coating composition is 10 to 20% by mass, and preferably 10% by mass or more from the viewpoint of suppressing the formation of pinholes in the resin insulating layer 12, and the resin From the viewpoint of suppressing the formation of a film dent in the insulating layer 12, the content is preferably 20% by mass or less. The ratio of the aprotic polar solvent content to the water content (aprotic polar solvent content / water content) is preferably 50/50 or less from the viewpoint of suppressing the occurrence of gelation. Also, from the viewpoint of increasing the electrodeposition coating speed, it is preferably 60/40 or less, more preferably 30/70 or less. When the aprotic polar solvent of the electrodeposition coating composition contains NMP, the content of NMP in the electrodeposition coating composition is preferably 7% by mass or more, more preferably 10% by mass or more, and preferably It is 30 mass% or less, More preferably, it is 23 mass% or less. When the aprotic polar solvent of the electrodeposition coating composition contains DMF in addition to NMP, the DMF content in the electrodeposition coating composition is preferably 1% by mass or more, more preferably 3% by mass or more, Moreover, Preferably it is 20 mass% or less, More preferably, it is 10 mass% or less. The ratio of the DMF content to the NMP content ((DMF content / NMP content) × 100) is preferably 5% or more, more preferably 8% or more, and preferably 100% or less, more Preferably it is 12% or less.

  Examples of the basic neutralizer include amino alcohol compounds such as 2-aminoethanol (hereinafter referred to as “AE”), 2,2-iminodiethanol, and 2-amino-2-methylpropanol; morpholine compounds such as morpholine. Compounds; piperazine-based compounds such as piperazine anhydride and piperazine hexahydrate; alkylamine-based compounds such as triethylamine and tripropylamine; piperidine-based compounds such as piperidine. The basic neutralizing agent preferably contains one or more of these. The basic neutralizing agent preferably contains a compound having an amino group and a hydroxyl group in the molecule from the viewpoint of suppressing the loss of the solid content of the electrodeposition coating composition due to the occurrence of precipitation, and contains an amino alcohol compound. Is more preferable, and it is still more preferable that 2-aminoethanol is included. The content of the basic neutralizing agent in the electrodeposition coating composition is, for example, 0.18 to 0.22% by mass. The number of milligrams of the basic neutralizing agent per gram of solid content in the electrodeposition coating composition is, for example, 26 to 40 mg. The neutralization rate of the electrodeposition coating composition with the basic neutralizing agent is, for example, 80 to 120%. The neutralization rate of the electrodeposition coating composition is measured by potentiometric titration.

  Examples of the colorant include C.I. I. Solvent Black 3, C.I. I. Solvent Black 27, C.I. I. Solvent black 7 etc. are mentioned. The colorant preferably contains one or more of these. From the viewpoint of uniformly coloring the colorant, C.I. I. It is preferable that Solvent Black 3 is included. The content of the colorant with respect to 100 parts by mass of the polyamideimide resin in the electrodeposition coating composition is, for example, 1 to 7 parts by mass.

  The water is, for example, ion exchange water or distilled water. The water content in the electrodeposition coating composition is, for example, 50 to 90% by mass.

  In addition, the electrodeposition coating composition may contain an aprotic nonpolar solvent such as naphtha or a protic polar solvent such as alcohol.

  The solid content concentration of the electrodeposition coating composition is 1 to 5% by mass, preferably 2% by mass or more from the viewpoint of obtaining excellent electrodeposition coating processability, and the corner corresponding portion 12c of the resin insulating layer 12 And from a viewpoint of forming the thickness of the short side corresponding | compatible part 12d thickly, Preferably it is 4 mass% or less. The electrodeposition coating composition may be diluted with a high solid content concentration.

The 50% diameter (D ₅₀ : median diameter) of the electrodeposition coating composition is, for example, 20 to 5000 nm. The 90% diameter (D ₉₀ ) is, for example, 100 to 20000 nm. The 10% diameter (D ₁₀ ) is, for example, _{10 to} 2000 nm. The particle size of these electrodeposition coating compositions is measured, for example, by a dynamic light scattering method using a zeta potential / particle size / molecular weight measurement system (ELSZ-2000ZS) manufactured by Otsuka Electronics Co., Ltd.

  The viscosity of the electrodeposition coating composition is measured with a B-type viscometer and is, for example, 1.0 to 2.0 mPa · s. The pH of the electrodeposition coating composition is measured with a pH meter and is, for example, 7-9. The liquid temperature of the electrodeposition coating composition is, for example, 10 to 30 ° C.

  The electrodeposition coating composition can be prepared, for example, by preparing an oil phase component and a water phase component each containing a polyamideimide resin, mixing them, and stirring to phase inversion emulsification. For this stirring, a general-purpose emulsifier, a disperser, a mixer, or a stirrer can be used. Specifically, for example, a rotor type or stator type mixer capable of giving high shear, a colloid mill, a homogenizer, a high pressure homogenizer and the like can be mentioned. The peripheral speed of the outer periphery of the stirring blade during stirring is, for example, 1 to 25 m / sec. The stirring time is, for example, 1 to 30 minutes.

  From the viewpoint of obtaining excellent productivity, the linear velocity when the flat wire 11 is passed through the electrodeposition coating composition is preferably 20 m / min or more, more preferably 25 m / min or more. From the viewpoint of suppressing the formation of the film dent and the pinhole and forming the resin insulating layer 12 with a sufficient thickness, it is preferably 40 m / min or less, more preferably 35 m / min or less.

  In the electrodeposition coating process, the tank containing the electrodeposition coating composition is housed in a compartment, and the flat wire 11 is immersed in the electrodeposition coating composition in a low vacuum atmosphere (100 Pa or more) or a nitrogen gas atmosphere. Good. The voltage application to the electrodeposition coating composition may be performed by a constant current method or a constant voltage method. The applied voltage is, for example, 10 to 100V.

  The electrodeposition coating composition adhering to the outer peripheral surface of the flat conducting wire 11 after exiting the electrodeposition coating composition and entering the baking furnace is concentrated by scattering the solvent component. The solid content concentration of the concentrated electrodeposition coating composition adhering to the outer peripheral surface is preferably 8% by mass or more, more preferably 10% by mass from the viewpoint of suppressing the formation of film dents and pinholes in the resin insulating layer 12. % Or more. This solid content concentration can be adjusted by the solid content concentration and viscosity of the original electrodeposition coating composition.

  The baking temperature, that is, the temperature inside the baking furnace is, for example, 200 to 500 ° C. The baking process time is, for example, 5 to 100 seconds. The baking treatment time can be adjusted by setting the linear speed of the flat wire 11. The baking process may be performed in one stage depending on a single baking process temperature, or may be performed in multiple stages at different baking process temperatures.

  According to the manufacturing method of the insulated wire 10 according to the embodiment as described above, it is possible to obtain the insulated wire 10 that has excellent adhesion of the resin insulating layer 12 to the flat conductive wire 11 and excellent damage resistance. For example, when a resin insulating layer is formed using a paint in which a resin is dissolved in an organic solvent, a thin film is formed in one process, and thus multiple processes are required. However, in the method for manufacturing the insulated wire 10 according to the embodiment, the solid content concentration is 2 to 4% by mass, including a polyamideimide resin, an aprotic polar solvent, and water. And electrodeposition coating is performed using an electrodeposition coating composition having an aprotic polar solvent content of 10 to 20% by mass, and a thick film is formed by one treatment. Excellent adhesion of the resin insulating layer 12 to the conducting wire 11 can be obtained. In addition, the electrodeposition coating composition contains a polyamideimide resin, an aprotic polar solvent, and water, has a solid content concentration of 2 to 4% by mass, and a content of the aprotic polar solvent is 10 to 15. Since it is mass%, the thickness of the corner | angular corresponding | compatible part 12c and the short side corresponding | compatible part 12d of the resin insulating layer 12 in the flat insulated wire 10 can be formed thickly.

  In the above embodiment, the rectangular insulated wire 10 having a flat cross-sectional shape is shown. However, the present invention is not particularly limited thereto. For example, the cross-sectional shape having the same dimension in the thickness direction and the width direction is square. In addition, the cross-sectional shape may be a circular round line.

[Test Evaluation 1]
(Insulated wire)
<Example 1>
Polyamideimide resin (5.8% by mass) having a number average molecular weight of 10000 and an acid value of 33 mgKOH / g, aprotic polar solvents NMP (36.8% by mass) and DMF (3.4% by mass), basic Neutralizing agent AE (0.19% by mass) and coloring agent C.I. I. Solvent Black 3 (0.50 parts by mass with respect to 100 parts by mass of polyamideimide resin) and water (54% by mass), and the content of aprotic polar solvent (NMP content + DMF content) is 40 masses %, And (DMF content / NMP content) × 100 = 9.2%, an O / W type dispersion electrodeposition coating composition having a solid content concentration of 5.8% by mass was prepared.

  This electrodeposition coating composition is diluted three times with water to form an electrodeposition varnish, and a flat copper wire having a thickness of 0.05 mm and a width of 0.3 mm is continuously applied to the electrodeposition varnish at a linear velocity of 30 m / min. The rectangular conductor wire pulled up from the electrodeposition varnish was passed through an upper zone (210 ° C.), a middle zone (245 ° C.), a lower zone (290 ° C.) ), And the outer zone of the rectangular conducting wire by electrodeposition coating through the upper zone (280 ° C.), the middle zone (300 ° C.) and the lower zone (320 ° C.) in order of the secondary baking furnace for baking the fusion layer. An insulated wire was produced by covering with a resin insulating layer. The obtained insulated wire was taken as Example 1.

<Example 2>
Example 2 was obtained by subjecting the insulated wire of Example 1 to additional heating at 300 ° C. for 5 minutes.

<Comparative Example 1>
An insulated wire was produced in the same manner as in Example 1 except that an electrodeposition coating composition containing a polyimide resin was used instead of the polyamideimide resin. This insulated wire was referred to as Comparative Example 1.

<Comparative example 2>
A flat wire was continuously passed through a paint in which a polyamide-imide resin was dissolved in a solvent at a wire speed of 30 m / min and baked to coat the outer peripheral surface of the flat wire with a resin insulating layer to produce an insulated wire. The obtained insulated wire was referred to as Comparative Example 2.

<Comparative Example 3>
Comparative Example 3 was obtained by subjecting the insulated wire of Example 1 to additional heating at 300 ° C. for 10 minutes.

(Test evaluation method)
<Exposure rate of flat wire>
About each of Example 1 and 2 and Comparative Examples 1-3, as shown in FIG. 3 in the side view after carrying out the rapid extension | expansion test based on JISC3216-3: 2011, length 4mm and width | variety of a center are shown. The exposure rate of the rectangular conducting wire in the 0.3 mm portion was determined by image processing.

<Young's modulus of resin insulation layer>
About each of Example 1 and 2 and Comparative Examples 1-3, the Young's modulus of the resin insulating layer was calculated | required with the microhardness meter (Shimadzu Corporation model number: DUH-211). The indenter used was a triangular pyramid with an expansion angle of 115 °.

<Softening start temperature of resin insulation layer>
For each of Example 1 and Comparative Example 1, using a thermomechanical analyzer (TMA7100 manufactured by Hitachi High-Tech Science Co., Ltd.), the spatula probe was pressed against the resin insulation layer of the insulated wire with a force of 25 mN at 10 ° C./min. Thermomechanical analysis (TMA) was performed to raise the temperature at a rate. And the temperature at the expansion start point of the displacement amount in the relationship between the temperature and the displacement amount of the probe was obtained from the graph as the softening start temperature.

(Test evaluation results)
Table 1 shows the test results.

According to the above results, in Examples 1 and 2 in which the exposure rate of the conducting wire is 7% or less and the Young's modulus of the resin insulating layer is 9.0 × 10 ³ N / mm ² or more, In addition to the excellent adhesion of the resin insulating layer, it is possible to expect excellent trauma resistance. On the other hand, in Comparative Example 1 where the exposure rate of the conducting wire is 7% or less, although excellent adhesion of the resin insulating layer to the rectangular conducting wire can be expected, the Young's modulus is lower than 9.0 × 10 ³ N / mm ^2. As such, excellent trauma resistance cannot be expected. Further, in Comparative Examples 2 and 3 in which the Young's modulus of the resin insulating layer is 9.0 × 10 ³ N / mm ² or more, although excellent trauma resistance can be expected, the exposure rate of the conductive wire is more than 7%. Therefore, high adhesion of the resin insulating layer to the flat conductor cannot be expected.

  FIG. 4 shows the relationship between temperature and probe displacement.

  From this graph, the softening start temperature of the polyamideimide resin of the resin insulating layer of Example 1 is as high as 270 ° C., whereas the softening start temperature of the polyimide resin of the resin insulating layer of Comparative Example 1 is as low as 230 ° C. I understand that.

[Test evaluation 2]
Polyamideimide resin (5.8% by mass) having a number average molecular weight of 10000 and an acid value of 33 mgKOH / g, aprotic polar solvent NMP (7.8% by mass), DMF (3.4% by mass), and DMI ( 29.0% by mass), basic neutralizing agent AE (0.19% by mass), and coloring agent C.I. I. Solvent Black 3 (0.50 parts by mass with respect to 100 parts by mass of polyamideimide resin) and water (54% by mass), content of aprotic polar solvent (NMP content + DMF content + DMI content) Is 40% by mass and (DMF content / (NMP content + DMI content)) × 100 = 9.2% Electrodeposition coating of O / W type dispersion having a solid content concentration of 5.8% by mass The composition was adjusted. This electrodeposition coating composition was diluted three times with water to obtain an electrodeposition varnish, and an insulated wire was produced in the same manner as in Example 1.

  It was confirmed that an insulated wire equivalent to Example 1 was obtained even when DMI was used as the aprotic polar solvent.

[Test Evaluation 3]
(Insulated wire)
Polyamideimide resin, aprotic polar solvents NMP and DMF, basic neutralizing agent AE, and coloring agent C.I. I. Electricity of O / W type dispersion liquid containing Solvent Black 3 and water and having a solid content concentration of 6.0% by mass and 10% by mass (DMF content / NMP content) × 100 = 9.2% Each coating composition was prepared.

  The electrodeposition coating composition having a solid content concentration of 6.0% by mass is diluted with water to have a solid content concentration of 1.0% by mass, 1.5% by mass, 2.0% by mass, 2.5% by mass, Seven electrodeposition paint compositions having 3.0% by mass, 4.0% by mass, and 5.0% by mass, and an electrodeposition paint composition having an undiluted solid content concentration of 6% by mass were prepared. . The content of the aprotic polar solvent (NMP content + DMF content) in the electrodeposition coating composition having a solid content concentration of 2.0 to 4.0% by mass was 10 to 15% by mass.

  Each electrodeposition coating composition is electrodeposited by continuously passing a high-purity copper flat conductor with a thickness of 0.05 mm and a width of 0.3 mm at a linear speed of 30 m / min. An insulated wire was produced by covering with a layer. The applied voltage was adjusted so that the thickness of the resin insulating layer was about 4 μm.

  Moreover, about the electrodeposition coating composition whose solid content concentration is 10 mass%, it dilutes with water and solid content concentration is 1.0 mass%, 1.5 mass%, 2.0 mass%, 2.5 mass%, Eight electrodeposition coating compositions having 3.0% by mass, 4.0% by mass, 5.0% by mass, and 6.0% by mass were prepared, and similarly, insulated wires were produced. The content of the aprotic polar solvent (NMP content + DMF content) in the electrodeposition coating composition having a solid content concentration of 2.0 to 4.0% by mass was 10 to 20% by mass.

(Test evaluation method)
The following test evaluation was performed about each obtained insulated wire.

<Thickness of resin insulation layer>
By cutting the insulated wire and observing the cross section, the thickness of the long side center corresponding part, the long side end corresponding part, the short side corresponding part, and the corner corresponding part of the resin insulating layer was measured.

<Dielectric breakdown voltage>
As shown in FIG. 5, a coiled insulated wire 10 was placed on a conductor 22 placed on a hot plate 21, and a weight 24 having a mass of 100 g was placed on the insulated wire 10 via an insulating plate 23. And the voltage was applied between the flat conducting wire of the insulated conducting wire 10, and the conductor 22, and the dielectric breakdown voltage which is a voltage at the time of raising a voltage gradually and destroying a resin insulating layer was measured. The boosting conditions were based on “JA.4.2 c) Metal foil method” in JIS C3216-5: 2011 “Winding test method—Part 5: Electrical characteristics”.

(Test evaluation results)
6A and 6B show the relationship between the solid content concentration of the electrodeposition coating composition and the thickness of each part of the resin insulating layer.

  According to these results, in the case of any electrodeposition coating composition having a solid content concentration before dilution of 6% by mass and 10% by mass, the overall tendency is that It can be seen that the long side end corresponding portion is relatively thick, and then the corner corresponding portion and the short side corresponding portion are formed relatively thin. Moreover, if the solid content concentration of the electrodeposition coating composition is 2 to 4% by mass, it can be seen that a resin insulation layer having a small thickness difference and high thickness uniformity can be formed. When the solid content concentration of the electrodeposition coating composition is lowered, the thickness of the short side corresponding portion is remarkably increased. However, since the solid content concentration is low, it is necessary to increase the applied voltage. This is considered to be because the electric field concentrates on the short side portion of.

  FIG. 7 shows the relationship between the solid content concentration of the electrodeposition coating composition and the dielectric breakdown voltage.

  According to this result, it can be seen that when the solid content concentration of the electrodeposition coating composition is 2 to 4% by mass, the dielectric breakdown voltage is relatively high, and therefore the resin insulating layer can be formed to a sufficient thickness.

[Test Evaluation 4]
(Insulated wire)
Polyamideimide resin, aprotic polar solvents NMP and DMF, basic neutralizing agent AE, and coloring agent C.I. I. Solvent Black 3 and water, the aprotic polar solvent content (NMP content + DMF content) is 13% by mass, 15% by mass, 17.5% by mass, and 20% by mass, and ( DMF content / NMP content) × 100 = 9.2% An electrodeposition coating composition of an O / W type dispersion having a solid content concentration of 2.0% by mass was prepared.

  Each electrodeposition coating composition is electrodeposited by continuously passing a high-purity copper flat conductor with a thickness of 0.05 mm and a width of 0.3 mm at a linear speed of 30 m / min. An insulated wire was produced by covering with a layer. The applied voltage was adjusted so that the thickness of the resin insulating layer was about 4 μm.

(Test evaluation method)
About each obtained insulated wire, the resin insulation layer was observed visually and the number of the coating dents per 1.5 m and the number of pinholes per 5 m were counted.

(Test evaluation results)
FIG. 8 shows the relationship between the content of the aprotic polar solvent in the electrodeposition coating composition and the number of film dents and pinholes.

  According to this result, it can be seen that the number of film dents and pinholes, particularly the number of pinholes, is reduced by decreasing the content of the aprotic polar solvent.

[Test Evaluation 5]
Polyamideimide resin, aprotic polar solvents NMP and DMF, basic neutralizing agent AE, and coloring agent C.I. I. Solvent Black 3 and water, the content of the aprotic polar solvent (NMP content + DMF content) is 13% by mass, (DMF content / NMP content) × 100 = 9.2% And the content of the basic neutralizing agent (AE content) is 0.19% by mass, 0.21% by mass, 0.23% by mass, and 0.25% by mass, and the solid content concentration is 3.3. An electrodeposition coating composition of a mass% O / W type dispersion was prepared.

  Each electrodeposition coating composition is electrodeposited by continuously passing a high-purity copper flat conductor with a thickness of 0.05 mm and a width of 0.3 mm at a linear speed of 30 m / min. An insulated wire was produced by covering with a layer. The applied voltage was adjusted so that the thickness of the resin insulating layer was about 4 μm.

  Moreover, the insulated wire was similarly produced by making line speed into 25 m / min and 35 m / min.

(Test evaluation method)
About each obtained insulated wire, the resin insulation layer was observed visually and the number of the coating dents per 1.5 m and the number of pinholes per 5 m were counted.

(Test evaluation results)
9A to 9C show the relationship between the content of the basic neutralizing agent in the electrodeposition coating composition and the number of film dents and pinholes.

  According to this result, it can be seen that when the content of the basic neutralizing agent is 0.21 to 0.23 mass%, the number of coating dents and pinholes is reduced.

  The present invention is useful for an insulated wire and a method for manufacturing the same.

DESCRIPTION OF SYMBOLS 10 Insulated wire 11 Rectangular conductor 12 Resin insulating layer 12a Long side center corresponding part 12b Long side end corresponding part 12c Corner corresponding part 12d Short side corresponding part 21 Hot plate 22 Conductor 23 Insulating plate 24 Weight

Claims (7)

An insulated wire comprising: a conductive wire; and a resin insulating layer formed of a polyamide-imide resin covering an outer peripheral surface of the conductive wire,
The exposed rate of the conducting wire in a portion having a predetermined width of 4 mm from the breaking point in a side view after a rapid extension test of the insulated wire based on JIS C3216-3: 2011 is 7% or less, and a micro hardness The insulated electric wire whose Young's modulus of the said resin insulating layer calculated | required by a meter is 9.0 * 10 < ³ > N / mm < ² > or more. In the insulated wire according to claim 1,
An insulated wire, wherein the conducting wire is a flat rectangular conducting wire having a flat cross-sectional shape. In the manufacturing method of the insulated wire described in Claim 1 or 2,
When the spatula-like probe is pressed against the resin insulating layer with a force of 25 mN and the temperature is raised at a rate of 10 ° C./min, the temperature at the displacement start point of the relationship between the temperature and the probe displacement is 250. Insulated wire that is above ℃. A method for producing an insulated wire in which a conductive wire is continuously passed through an electrodeposition coating composition of an O / W type dispersion and electrodeposited to coat the outer peripheral surface of the conductive wire with a resin insulating layer,
The electrodeposition coating composition contains a polyamide-imide resin, an aprotic polar solvent, and water, has a solid content concentration of 2 to 4% by mass, and a content of the aprotic polar solvent is 10%. The manufacturing method of the insulated wire which is -20 mass%. In the manufacturing method of the insulated wire described in Claim 4,
The manufacturing method of the insulated wire which sets the line speed when passing the said conducting wire through the said electrodeposition coating composition to 20-40 m / min. In the manufacturing method of the insulated wire described in Claim 4 or 5,
The manufacturing method of the insulated wire whose solid content concentration in the electrodeposition coating composition adhering to the outer peripheral surface of the said conducting wire after leaving the said electrodeposition coating composition is 10 mass% or more. In the manufacturing method of the insulated wire in any one of Claims 4 thru | or 6,
An insulated wire, wherein the conducting wire is a flat rectangular conducting wire having a flat cross-sectional shape.