JP7012415B2 - Wire with terminal - Google Patents

Description

The present invention relates to, for example, a coating material used for corrosion protection of automobile parts and the like, a resin coating structure using the coating material, an electric wire with a terminal, and the like.

Conventionally, in the fields of automobiles, OA equipment, home appliances and the like, electric wires made of copper-based materials having excellent electrical conductivity have been used as power lines and signal lines. In particular, in the field of automobiles, the performance and functionality of vehicles are rapidly increasing, and the number of various electric devices and control devices mounted on vehicles is increasing. Therefore, along with this, the number of electric wires with terminals used tends to increase.

On the other hand, as environmental problems are attracting attention, weight reduction of automobiles is required. Therefore, an increase in weight due to an increase in the amount of wire harness used becomes a problem. Therefore, instead of the conventionally used copper wire, a lightweight aluminum electric wire is attracting attention.

Here, a connection terminal is used when connecting such electric wires or in a connection portion of equipment or the like. However, even in the case of an electric wire with a terminal using an aluminum electric wire, copper having excellent electrical characteristics may be used for the terminal portion because of the reliability of the connection portion and the like. In such a case, the aluminum electric wire and the copper terminal are joined and used.

However, when dissimilar metals are brought into contact with each other, so-called galvanic corrosion may occur due to the difference in standard electrode potential. In particular, since the standard electrode potential difference between aluminum and copper is large, corrosion on the electrically base aluminum side progresses due to the influence of water scattering and dew condensation on the contact portion. For this reason, the connection state between the electric wire and the terminal at the connection part becomes unstable, and there is a risk that the contact resistance will increase, the electrical resistance will increase due to the decrease in the wire diameter, and the wire will break, resulting in malfunction or malfunction of the electrical components. be.

Therefore, a method of covering the connection portion between the electric wire and the terminal with a resin member has been proposed. For example, there has been proposed an electric wire with a terminal coated by applying a resin member to a conductor wire exposed between a coated crimping portion and a conducting wire crimping portion (Patent Document 1).

FIG. 5 is a partial cross-sectional view of a conventional electric wire with a terminal. Normally, in the vicinity of the tip of the coated conductor wire 111, the covering portion 115 is removed and the inner conductor wire 103 is exposed. The exposed conductor 103 is crimped by the conductor crimping portion 107, and the covering portion 115 is crimped by the covering crimping portion 109. Since a part of the lead wire 103 is exposed in the barrel inter-barrel portion 108 between the cover crimping portion 109 and the conductor crimping portion 107, the conductor crimping portion 107 from the barrel inter-barrel portion 108 is covered with the resin member 117.

However, at the boundary between the end of the covering portion 115 and the exposed portion of the conducting wire 103, a minute gap (X in the figure) is likely to occur due to a change in the outer diameter. When such a gap is generated, the moisture that has permeated between the coated crimping portion 109 and the coated portion 115 may permeate into the conductor 103 and the conductor crimping portion 107. Therefore, in order to ensure sufficient anticorrosion properties, it is necessary to infiltrate the resin member 117 into the gap X and cure it.

As a method of filling the gap X with the resin member 117, for example, there is a method of adjusting the viscosity of the resin member 117 at the time of coating. However, even if the resin member 117 can be filled in the gap X, there is a problem that when the ultraviolet rays are irradiated, the ultraviolet rays do not reach the back side of the conducting wire 103 and it takes time to cure.

As described above, as a method for curing the deep portion of the wire crimping portion, a chain transfer agent composed of an ultraviolet curing material, a compound containing at least one selected from a urethane bond, a urea bond, and an isocyanate group, and a metal-containing compound. A UV curable composition containing the above has been proposed (for example, Patent Document 2).

JP-A-2017-102998 Japanese Unexamined Patent Publication No. 2011-123281

However, in the method of Patent Document 2, since the metal-containing compound is added as a chain transfer agent, there is a problem that the metal-containing compound absorbs ultraviolet rays. Therefore, there is a problem that the ultraviolet irradiation time for curing becomes long.

In particular, when a resin member is applied to an electric wire with terminals and cured, it is desirable that the applied resin member be visible. This is to visually confirm whether the conductor is surely covered with the resin member. Therefore, instead of a completely transparent resin member, a colored resin member such as colored resin member may be used. However, if coloring is performed in order to improve the visibility of the resin member in this way, there is a problem that it becomes difficult for ultraviolet rays to reach deep parts.

The present invention has been made in view of such a problem, and a coating film capable of shortening the curing time of a deep resin without using a metal-containing compound even when used in a colored manner. It is an object of the present invention to provide a material, a resin coating structure using the material, and an electric wire with a terminal.

In order to achieve the above-mentioned object, the present invention comprises a resin coating structure in which a covering material is applied to a covering target member and cured, and the coating target member is a terminal-equipped electric wire in which a covering lead wire and a terminal are connected. The covered lead wire includes a covered portion and a lead wire exposed from the tip of the covered portion, the terminal has a terminal body and a crimping portion, and the crimping portion is crimped with the lead wire. It is provided with a lead wire crimping portion, a coated crimping portion to which the covering portion is crimped, and a barrel inter-barrel portion between the lead wire crimping portion and the covering crimping portion, and at least the lead wire crimping portion is provided from the barrel inter-barrel portion. The portion where the radicals are exposed is covered with the coating material, the coating material has a photoreaction initiator added to the resin of the base material, and the photoreaction initiator emits light in the ultraviolet region. The first photoreaction initiator comprises an aminoketone-based first photoreaction initiator that generates radicals by irradiation and a second photoreaction initiator having photobleaching property with respect to light in the ultraviolet region. Radicals are generated by irradiating light in the wavelength range of 365 nm to 405 nm, and the second photoreaction initiator contains at least one of an acylphosphine oxide-based photoreaction initiator or an oxime ester-based photoreaction initiator. , An electric wire with a terminal, which is excited by light in the ultraviolet region and contains a thioxanthone-based sensitizer that enhances radical generation in 365 nm to 405 nm by donating electrons to the first photoreaction initiator .

According to the present invention, it is possible to obtain an electric wire with a terminal which is hardened by applying a coating material to the lower part of the conducting wire.
Further , since the photoreaction initiator contains an aminoketone-based first photoreaction initiator and the photoreaction initiator contains a second photoreaction initiator having photobleaching property, it cures when irradiated with light. It is possible to reduce the absorbance of the resin that has started, and even if the coating material is colored, it is possible to allow light to reach deeper and proceed with curing. Therefore, the coating material can be cured to a deep part in a short time.

In particular, the first photoreaction initiator generates radicals by irradiating light in a wavelength region of 365 nm to 405 nm, so that the coating material can be reliably irradiated by irradiation with light in an ultraviolet region.

In addition, an aminoketone-based photoreaction initiator is contained by containing a thioxanthone-based sensitizer that is excited by light in the ultraviolet region and donates electrons to the first photoreaction initiator to enhance radical generation at 365 nm to 405 nm. The absorption wavelength of the light can be shifted to the long wavelength side. For example, by shifting the absorption band of the α-aminoketone system of 320 nm to the long wavelength side, it can be cured even by light having a longer wavelength. Therefore, the curability can be further improved by using a light source having a light source of 385 nm, a light source having a diameter of 405 nm, or a light source containing both.

Further, since the second photoreaction initiator contains at least one of the acylphosphine oxide-based photoreaction initiator and the oxime ester-based photoreaction initiator, the photobleaching property is more reliably obtained at a wavelength around 365 to 380 nm. Can be demonstrated.

The difference in the curing reaction rate calculated based on infrared light absorption between the coating material on the surface portion and the coating material on the bottom surface side of the terminal on the back side of the conducting wire in the inter-barrel portion is within 3%. desirable.

According to the third invention, it is possible to obtain an electric wire with a terminal which is hardened by applying a coating material to the lower part of the conducting wire.

In particular, if the difference in the curing reaction rate calculated based on infrared light absorption between the coating material on the surface portion between the barrels and the coating material on the bottom surface side of the terminal on the back side of the conducting wire is within 3%, the coating material. Since the difference in the curing reaction rate between the surface and the deep part of the surface is small, deterioration of the coating material can be suppressed in the thermal shock test.

According to the present invention, a coating material capable of shortening the curing time of a deep resin without using a metal-containing compound even when used in color, a resin coating structure using the coating material, and a resin coating structure using the coating material. Wires with terminals can be provided.

The perspective view which shows the electric wire 10 with a terminal. The cross-sectional view which shows the electric wire 10 with a terminal. The figure which shows the terminal 1 and the coated conductor wire 11 before crimping. The figure which shows the positive pressure test method of the electric wire 10 with a terminal. Partial cross-sectional view of a conventional electric wire with a terminal.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing an electric wire 10 with a terminal, and FIG. 2 is a sectional view. Note that FIG. 1 is a perspective view of the coating material 17. The electric wire 10 with a terminal is configured by connecting the terminal 1 and the coated conductor wire 11.

The coated conductor 11 includes a conductor 13 made of aluminum or an aluminum alloy, and a covering portion 15 that covers the conductor 13. That is, the coated conductor 11 includes a coated portion 15 and a conductor 13 exposed from the tip thereof. The conductor 13 is, for example, a stranded wire in which a plurality of strands are twisted together.

The terminal 1 is an open barrel type and is made of copper or a copper alloy. A coated conducting wire 11 is connected to the terminal 1. The terminal 1 is configured by connecting the terminal body 3 and the crimping portion 5 via the transition portion 4. The transition portion 4 located between the crimping portion 5 and the terminal body 3 opens upward.

The terminal body 3 is formed by forming a plate-shaped material having a predetermined shape into a tubular body having a rectangular cross section. The terminal body 3 has an elastic contact piece formed by folding a plate-shaped material into a rectangular cylinder. The terminal body 3 is connected by inserting a male terminal or the like from the front end portion. In the following description, an example is shown in which the terminal body 3 is a female terminal that allows insertion of an insertion tab (not shown) such as a male terminal, but in the present invention, the detailed shape of the terminal body 3 is shown. Is not particularly limited. For example, a male terminal insertion tab may be provided instead of the female terminal body 3.

The crimping portion 5 is a portion to be crimped to the coated conducting wire 11, and before crimping, the crimping portion 5 has a barrel shape having a substantially U-shaped cross section perpendicular to the longitudinal direction of the terminal 1. The crimping portion 5 of the terminal 1 has a lead wire crimping portion 7 that crimps the lead wire 13 exposed from the coated lead wire 11 to the tip end side of the coated lead wire 11, a coated crimping portion 9 that crimps the coated portion 15 of the coated lead wire 11, and a lead wire crimping portion. It is composed of a barrel-to-barrel portion 8 between the portion 7 and the covering crimping portion 9.

A part of the inner surface of the wire crimping portion 7 is provided with serrations (not shown) in the width direction (direction perpendicular to the longitudinal direction). By forming the serrations in this way, when the conductor 13 is crimped, the oxide film on the surface of the conductor 13 is easily broken, and the contact area with the conductor 13 can be increased.

At the tip of the coated conductor 11, the coated portion 15 is peeled off, and the inner conductor 13 is exposed. The coated portion 15 of the coated conductor 11 is crimped by the coated crimping portion 9 of the terminal 1. Further, the conductor 13 exposed by peeling off the covering portion 15 is crimped by the conductor crimping portion 7. In the conductor crimping portion 7, the conductor 13 and the terminal 1 are electrically connected. The end face of the covering portion 15 is located at the barrel-to-barrel portion 8 between the covering crimping portion 9 and the lead wire crimping portion 7.

In the present invention, at least the portion where the conductor 13 from the barrel inter-barrel portion 8 to the conductor crimping portion 7 is exposed is covered with the coating material 17. That is, at least the portion where the conductor 13 from the barrel inter-barrel portion 8 to the conductor crimping portion 7 is exposed is covered with the coating material 17, and the conductor 13 is not exposed to the outside by the coating material 17. The coating material 17 functions as a food-proof material, and forms a resin coating structure by being applied to an electric wire with a terminal, which is a covering target member, and cured.

Here, the coating material 17 is configured by adding a photoreaction initiator to the resin of the base material containing the necessary components of the oligomer, the diluting monomer, the polyol, and the silane coupling agent. That is, the coating material 17 has ultraviolet curability. Further, the coating material 17 of the present invention contains at least two kinds of photoreaction initiators, and includes an aminoketone-based first photoreaction initiator that generates radicals by irradiating light in an ultraviolet region, and an ultraviolet region. It contains a second photoreaction initiator having photobleaching property with respect to light. The coating material 17 of the present invention does not contain a metal-containing compound (metal salt or metal complex). Further, the coating material 17 may contain additives such as a sensitizer, a pigment, a dye, and a lubricant.

The aminoketone-based photoreaction initiator of the first photoreaction initiator generates radicals by irradiating light in a wavelength region of 365 nm to 405 nm. The aminoketone-based photoreaction initiator is not easily affected by the curability even when the ultraviolet curable resin containing a pigment or dye is cured for visibility. Therefore, even when the coating material 17 which is not completely colorless and transparent is applied to the electric wire with terminals, it can be cured to a deep part and it can be easily grasped whether or not the coating material 17 is applied by coloring. ..

Further, it is desirable to include a thioxanthone-based sensitizer that is excited by light in the ultraviolet region and donates electrons to the first photoreaction initiator to enhance radical generation at 365 nm to 405 nm. By mixing the aminoketone-based photoreaction initiator with the thioxanthone-based sensitizer, the absorption wavelength shifts to the long wavelength side. That is, it can be cured by a light source on the longer wavelength side. Since the light from the light source having a long wavelength easily reaches a deep part, for example, by using a light source having a diameter of 385 nm, a light source having a diameter of 405 nm, or a light source containing both, the curability can be further improved.

Further, it is desirable that the second photoreaction initiator contains at least one of an acylphosphine oxide-based photoreaction initiator or an oxime ester-based photoreaction initiator. Both the acylphosphine oxide-based photoreaction initiator and the oxime ester-based photoreaction initiator have photobleaching properties in the vicinity of 380 nm, and the light transmittance is improved by irradiating light of the wavelength. ..

Photobleaching is also described as photobleaching and photobleaching, and is one of the environmental effects, and refers to the photochemical properties rarely seen in excited fluorescent molecules. This reaction occurs because the excited fluorescent material is chemically activated and unstable compared to the ground state. As a result of this reaction, it means that the fluorescent molecule eventually changes to a low fluorescence structure. In the invention according to the present embodiment, when the photoinitiator absorbs light in a certain ultraviolet region and generates radicals to initiate polymerization on the ultraviolet curable resin, the molecule of the photoreaction initiator after radical generation is used. The fact that the conjugate bond is broken and the absorbance in the ultraviolet region decreases is called photobleaching. As a result, since the light in the ultraviolet region can be transmitted to the inside, the curing can proceed smoothly even with a thick film.

Examples of the α-aminoketone-based photoinitiator include 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one, which has a strong absorption peak at 260 to 340 nm, 260 to. 2-Benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1,2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1-, which has an absorption peak at 400 nm [4- (4-morpholinyl) phenyl] -1-butanone can be mentioned. Examples of commercially available products include IRGACURE907, IRGACURE369, and IRGACURE379 (trade names, all manufactured by BASF).

In addition, 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropane-1-one (907), 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone- 1 (369), 2- (dimethylamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone (379) and a thioxanthone-based sensitizer. By using 2,4-diethylthioxanthone (commercially available, Kayacure DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.)) having absorption at 260 to 410 nm, the absorption coefficient (ε) at 405 nm can be increased. It becomes higher, contributes to deeper curing, and can react more efficiently.

Examples of the acylphosphine oxide-based photoreaction initiator include bis (2,4,6-trimethylbenzoyl) -phenylphosphinoxide and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide. Examples of commercially available products include Lucirin-TPO, DAROCUR-TPO, and IRGACURE819 (trade names, all manufactured by BASF).

Since these photoinitiators have strong absorption peaks at 260-440 nm, LED wavelengths of 385 nm and 395 nm are more effective than 365 nm. Further, since the acylphosphine oxide-based photoreaction initiator exhibits a photobleaching effect in which absorption is eliminated by decomposition, it is possible to increase the degree of curing not only on the surface but also in the deep part. That is, although the acylphosphine oxide-based photoreaction initiator absorbs in the long wavelength region (near 385 nm) at the start of irradiation with ultraviolet rays, the absorption in the long wavelength region disappears as the photopolymerization reaction progresses. Therefore, as the photopolymerization reaction proceeds, the ultraviolet rays reach the deep part, and the degree of curing in the deep part can be increased.

The following coloring pigments and dyes can be used. Cyanine compounds, phthalocyanine compounds, naphthoquinone compounds, diimmonium compounds, naphthalocyanine compounds, squalium dyes, quinone compounds, azo compounds, quinacridone, dioxane, bensuimidazolone, carbon black and the like can be used. One of these components may be used alone, or two or more thereof may be used in combination. An effective photoreaction initiator for curing a deep portion from the surface of the colored ultraviolet curable resin is, for example, an α-aminoketone-based photoreaction initiator or an acylphosphine oxide-based photoreaction initiator. As described above, by adding the α-aminoketone-based photoreaction initiator and the thioxanthone-based sensitizer having an absorption peak in the long wavelength region, the absorption peak in the long wavelength region (particularly the above-mentioned 405 nm) is increased. Further, by combining an acylphosphine oxide-based photoreaction initiator, the degree of curing on the surface and inside can be efficiently increased.

Examples of the oxime ester-based photoreaction initiator include 1.2-octanedione, 1- [4- (phenylthio)-, 2- (0-benzoyloxime)], etanone, 1- [9-ethyl-6. -(2-Methylbenzoyl) -9H-carbazole-3-yl]-, 1- (0-acetyloxime) can be mentioned. Examples of commercially available products include IRGACURE OXE01 and IRGACURE OXE02 (both trade names, manufactured by BASF), but IRGACURE OXE01 (trade name, manufactured by BASF) has photobleaching properties.

In this way, by adding a thioxanthone-based sensitizer to the α-aminoketone-based photoreaction initiator effective for curing a deep portion of the colored ultraviolet curable resin from the surface, a long wavelength region (particularly the above-mentioned 405 nm) is added. ) Can have a high absorption peak, and by using photobleaching in combination with a photoreaction initiator such as an acylphosphine oxide system, curing is started from the surface irradiated with light, and at the cured site. Since the transmittance increases, the light reaches a deeper part and the coating material 17 can be cured in a short time.

As described above, the main reaction of the ultraviolet curable resin is radical polymerization, and the radical generated by the decomposition of the photoreaction initiator by the action of ultraviolet rays attacks the double bond of the modified acrylate to initiate radical polymerization. Will be done. The base resin is a modified acrylate in which acrylic groups are added to both ends of a main chain such as epoxy, polyester, or urethane, and the acrylic groups serve as reaction groups to be polymerized by ultraviolet rays. Further, by imparting other functions of the modified acrylate which is the main component of the ultraviolet curable resin, the portion where the ultraviolet rays are difficult to reach can be cured at the same time as the ultraviolet irradiation, or can be cured during the process. For example, the modified acrylate can impart ultraviolet curability, moisture curability, thermosetting, and anaerobic curability, respectively. Deep curability can also be imparted by imparting both properties of ultraviolet curing, moisture curing, or anaerobic curing in a well-balanced manner.

For example, silicon-modified acrylate is preferably used for moisture curing, and can be further cured by moisture after UV curing is completed. In addition, thermosetting cures the surface of the resin that is difficult to heat cure by irradiating it with ultraviolet rays by using it in combination with a thermosetting epoxy-modified acrylate, and further heats it to completely cover the parts that are difficult to reach by ultraviolet rays in a short time. Can be cured. With regard to anaerobic curing, under the condition that metal ions intervene, curing is completed relatively quickly by promoting anaerobic curing by irradiation heat at the time of curing by ultraviolet rays and by blocking air on the surface portion by ultraviolet curing.

The amount of the photoreaction initiator added to the base metal resin is preferably 0.5% by mass or more and 3.0% by mass or less. The amount of the photoreaction initiator added can be specified, for example, by measuring the absorption wavelength of the photoreaction initiator by ultraviolet absorption spectrum analysis.

Further, in the present embodiment, the curing reaction rate of the coating material 17 on the surface portion of the inter-barrel portion 8 and the coating material 17 on the bottom surface side of the terminal 1 on the back side of the conducting wire 13 is calculated based on infrared light absorption. The difference is preferably within 3%.

Here, the curing reaction rate of the coating material 17 can be measured as follows by measuring the infrared light absorption peak having a wave number of 1407 cm ^-1 with the peak appearing at a wavelength of 1506 to 1570 cm ^-1 as a reference peak. can.

For the prepared coating material, the acrylic double bond reaction rate of the ultraviolet curable resin is measured by microscopic ATR (Attenuated Total Reflection) measurement by the FT-IR method, and the curing reaction rate is evaluated. ATR measurement is a quantitative measurement in the depth direction of a sample, in which a crystal having a higher refractive index than the sample is brought into contact with the sample, infrared light is incident on the sample, and the spectrum absorbed by the sample and reflected by the crystal is measured. It is a measurement. By using crystals having different refractive indexes, the amount of submergence of the sample in the depth direction can be changed. The amount of sneaking can be calculated using Snell's law shown in the following equation.

Here, dp is the amount of diving, λ is the wavelength of infrared light, n ₁ is the refractive index of the crystal, n ₂ is the refractive index of the sample, and θ is the incident angle of infrared light. As is clear from Equation 1, the relationship between the wavenumber of infrared light and the amount of submergence by ATR measurement depends on the crystal used. The refractive index of a typical ATR crystal is KRS-5: 2.40, ZnSe: 2.41, Ge: 4.01, diamond: 2.37, Si: 3.41. When ATR measurement is performed using a diamond crystal, for example, at a wave number of 1407 cm ^-1 , the amount of submergence is 1.4 μm. At a wave number of 810 cm ^-1 , the amount of submergence is 2.4 μm.

By microscopic ATR measurement by the FT-IR method, the coating material is taken out from each of the surface and the deep part after curing and evaluated. From the evaluation results by the FT-IR method, it is possible to obtain an infrared light absorption peak and a reference peak in each of the surface and deep coating materials. Then, from these absorption peaks and reference peaks in the surface and the deep part, the reaction rate difference between the surface and the deep part can be obtained by using Equation 2.

Curing reaction rate difference (%)
= (1- (S _Abs. / S _Ref. ) / (DA _Abs. / D _Ref. )) × 100 ... Equation 2
However, S _Abs. Is the absorption peak of the coating material on the surface, S _Ref. Is the reference peak of the coating material on the surface, D _Abs. Is the absorption peak of the coating material in the deep part, and D _Ref. Is the absorption peak of the coating material in the deep part. It is a reference peak.

When the difference in the curing reaction rate calculated based on the infrared light absorption is within 3%, there is almost no difference in the curing reaction rate between the surface and the deep portion of the coating material, so that the thermal shock resistance can be improved.

Next, a method of manufacturing the electric wire 10 with a terminal will be described. First, as shown in FIG. 3, a coated conductor 11 is prepared by peeling off the terminal 1 and the tip of the coated portion 15 to expose the conductor 13.

Next, the conductor 13 of the coated conductor 11 is arranged in the conductor crimping portion 7, and the covering portion 15 is arranged in the coated crimping portion 9. At this time, the tip end portion of the covering portion 15 is located at the barrel inter-barrel portion 8. Next, the conductor 13 is crimped by the wire crimping portion 7, the coated portion 15 is crimped by the coated crimping portion 9, and the coated conductor 11 and the terminal 1 are connected by crimping.

Next, at least the coating material 17 is applied to the exposed portion of the conductor wire 13 from the barrel inter-barrel portion 8 to the conductor wire crimping portion 7 with a dispenser or the like and cured. From the above, the electric wire 10 with a terminal can be obtained.

The viscosity of the coating material 17 at the time of coating is preferably 300 to 3000 mPa · s. If the viscosity of the coating material 17 is too high, it becomes difficult to allow the coating material 17 to penetrate into the conducting wire 13 and to penetrate the lower portion of the conducting wire 13. On the other hand, if the viscosity of the coating material 17 is too low, the applied coating material 17 will flow, making it difficult to secure a desired thickness.

As described above, according to the present embodiment, since the photoreaction initiator contains an aminoketone-based first photoreaction initiator, even when the resin is colored by a colorant or the like, it can be efficiently cured. Since it contains a second photoreaction initiator that has photobleaching properties against light in the ultraviolet region, when light is applied and curing starts, the absorbance of the resin decreases due to photobleaching, and the light goes deeper. Can be reached. As described above, in the present embodiment, the aminoketone-based first photoreaction initiator and the second photoreaction initiator having photobleaching property are used in combination to, for example, colorize for visibility. Even so, it is possible to efficiently cure the deep portion of the coating material 17. The coating material 17 of the present embodiment is effective not only when coloring is performed by adding a colorant or the like, but also when the resin itself is colored, and when there is a possibility of discoloration of the resin or the like. Of course, it is also effective when it is colorless and transparent during manufacturing and storage, such as when it is colored at the time of application.

Further, by mixing the thioxanthone-based sensitizer, the absorption wavelength of the aminoketone-based photoreaction initiator can be shifted to the long wavelength side, and the absorption in the vicinity of, for example, 405 nm can be enhanced. Therefore, the coating material 17 can be cured by using a light source having a longer wavelength, so that the light can reach a deeper part.

In the present embodiment, the member to be covered is the electric wire 10 with a terminal to which the coated conductor 11 and the terminal 1 are connected, and the coating material 17 is applied to the electric wire 10 with a terminal to be a member to be covered and cured. However, the present invention is not limited to this. The coating material 17 can also be used in other fields as long as it is a covering target member that needs to form a resin film for corrosion protection and protection and allow the coating material 17 to penetrate deeper into the portion. For example, any of the processes for applying resin to the member to be coated, such as an optical fiber coating process, a resin coating process for electronic parts and optical pickups, a print resist curing process, and a resin coating process when bonding various members. It is also available in the field.

Next, a prototype electric wire with a terminal was made using a plurality of coating materials, and each sample was tested. This will be described below.

As described above, the coated conductor was crimped at the crimping portion of the terminal, and the coating material was applied to the exposed portion of the conductor and cured. At this time, various electric wires with terminals were obtained by changing the type and viscosity of the coating material to be applied. Table 1 shows each condition and result.

The resin formulation in the table indicates the type of photoreaction initiator, etc. to be mixed with the base resin, and IRGACURE 379 (trade name, manufactured by BASF) is used as the aminoketone-based photoreaction initiator, and a thioxanthone-based sensitizer. KayaCure DETX-S (trade name, manufactured by Nippon Kayaku Co., Ltd.) was used as the initiator, and IRGACURE 379 (A in the table) and Lucirin-TPO9 (B in the table) were used as the acylphosphine oxide-based photoreactive initiators. Also used (trade name, manufactured by BASF), and IRGACURE OXE01 (trade name, manufactured by BASF) was used as the oxime ester-based photoreaction initiator. In addition, as other photoreaction initiators, a hydroxyketone-based photoreaction initiator (IRGACURE 184 (trade name, manufactured by BASF)) and an alkiferone-based photoreaction initiator (IRGACURE 1173 (trade name, manufactured by BASF)). Was used. The droxyketone-based photoreaction initiator and the alkiferone-based photoreaction initiator do not have photobleaching properties in the ultraviolet region. Further, some resins were colored by blending 2% by mass of Pigment Red 122 (quinacridone) as a colorant.

In addition, the electric wire with a terminal whose coating material is hardened according to each wavelength is disassembled, and the coating material on the surface portion and the deep portion in the inter-barrel portion (the surface portion in the inter-barrel portion and the coating material on the bottom surface side of the terminal on the back side of the conducting wire). ) Was collected and microscopic ATR measurement was performed by the FT-IR method. As a device for microscopic ATR measurement of the FT-IR method, 660/610IR of VARIAN (currently Agilent Technologies) was used. In addition, a silver / cadmium / telluride compound (MCT) detector was used as the detector. As the measurement conditions, the scan speed was set to 25 kHz, the incident angle was set to 45 degrees, the resolution was set to 4 cm ^-1 , and the aperture size was set to 100 μm × 100 μm.

From the evaluation results by the FT-IR method, the absorption peak and the reference peak of infrared light were obtained on the surface and the deep part, respectively, and the above-mentioned formula 2 was used to obtain the difference in the degree of curing between the surface and the deep part (difference in curing reaction rate). Asked. Those having a curing degree difference of 3% or less were evaluated as ◯, those having a curing degree difference of more than 3% and 10% or less were evaluated as Δ, and those having a curing degree difference of more than 10% were evaluated as x.

In addition, a cold shock test was conducted on each wire with terminals at 120 ° C x 30 minutes to -40 ° C x 30 minutes for 1000 cycles, and the sealing performance of the wire with terminals after the cold shock test was evaluated at positive pressure. did. The sample used for the thermal shock test was cured by irradiating it with light of 385 nm.

FIG. 4 shows an outline of the positive pressure test method. One end of the electric wire 10 with a terminal was put into a water tank 21 filled with water, and pressurized air was sent from the end of the coated conducting wire 11 toward the terminal 1 by a regulator 22. The air pressure was 49 kPa. The sealing property at positive pressure was evaluated as to whether or not air was sent from the coated conductor of the electric wire with a terminal toward the terminal and air leaked from the terminal 1.

In the "positive pressure test after the cold test" in the table, those having no leakage in the positive pressure test after the above-mentioned cold impact test were marked with ◯, and those with some leaks were marked with x.

In addition, we confirmed the "visibility" of each electric wire with terminals after the coating material was cured. Those in which it was easy to grasp that the conducting wire was completely covered with the coating material were marked with ◯, and those in which the presence or absence of the coating material was difficult to understand were marked with x.

As a comprehensive evaluation, 〇 is evaluated for both the positive pressure test and visibility after the cold test, and x is evaluated for either the visibility or the positive pressure test after the cold test. did.

From the results, in Examples 1 to 3 containing a photochemical initiator, an aminoketone-based photoreaction initiator, and a thioxanthone-based sensitizer, even if they were colored, the positive pressure test after the cold test was 〇. Because it was colored, the visibility was 〇, and the overall evaluation was 〇. This is particularly long due to the effect of the photochemical initiator having photobleaching property and the effect of shifting the absorption wavelength of the aminoketone-based photoreaction initiator, which is not easily affected by it even if it is colored, to the longer wavelength side. This is because it was possible to cure deeply by irradiating light on the wavelength side.

On the other hand, in Comparative Examples 1 to 4, which are only photoreaction initiators having photobleaching properties, in the case of being colored (Comparative Examples 1, 3 and 4), the positive pressure test after the cold test is ×. In the case of not being colored (Comparative Example 2), the visibility was x. This is because when the resin is not colored, the photobleaching effect sufficiently promotes curing to a deep part, but when it is colored, it is more susceptible to the effect than the aminoketone-based photoreaction initiator. It is probable that the hardening in the deep part was slightly weakened.

Further, in Comparative Examples 5 to 7 in which only the aminoketone-based photoreaction initiator was used, the positive pressure test after the cold test was x regardless of the presence or absence of coloring. This is because the deep curability is lower only with the aminoketone-based photoreaction initiator as compared with the photoreaction initiator having photobleaching property. Although details are omitted, the addition of a thioxanthone-based sensitizer reduced the value of the difference in the degree of curing and improved the deep curability.

Further, in Comparative Examples 8 to 9, which are only photoreaction initiators having no photobleaching property without using an aminoketone-based photoreaction initiator, the difference in curing degree between the surface and the deep part is 10 at any wavelength. The result was that the curing did not proceed to the deep part, exceeding%.

Although the embodiments of the present invention have been described above with reference to the attached drawings, the technical scope of the present invention does not depend on the above-described embodiments. It is clear that a person skilled in the art can come up with various modifications or modifications within the scope of the technical ideas described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs to.

1 ………… Terminal 3 ………… Terminal body 4 ………… Transition part 5 ………… Crimping part 7 ………… Conductor crimping part 8 ………… Barrel-to-barrel part 9 ………… Covered crimping part 10 …… Wire with terminal 11 ………… Covered lead wire 13 ………… Lead wire 15 ………… Covered part 17 ………… Coating material 21 ………… Water tank 22 ………… Regulator 103 ………… Lead wire 107 ………… Lead wire crimping part 108 ………… Barrel Inter-covered part 109 ………… Covered crimping part 111 ………… Covered conductor 115 ………… Covered part 117 ………… Resin member

Claims (2)

In a resin coating structure in which a covering material is applied to a covering target member and cured , the covering target member is an electric wire with a terminal in which a coated conductor and a terminal are connected.
The coated conductor includes a coated portion and a conductor exposed from the tip of the coated portion.
The terminal has a terminal body and a crimping portion, and the crimping portion includes a conductor crimping portion to which the conductor is crimped, a coated crimping portion to which the coated portion is crimped, and the conductor crimping portion and the coated crimping portion. It is provided with a barrel-to-barrel portion between the portions, and at least a portion from the barrel-to-barrel portion to the conductor crimping portion where the conductor is exposed is covered with the coating material.
The coating material has a photoreaction initiator added to the resin of the base material.
The photoreaction initiator includes an aminoketone-based first photoreaction initiator that generates radicals by irradiating light in the ultraviolet region and a second photoreaction initiator having photobleaching property with respect to light in the ultraviolet region. Including
The first photoreaction initiator generates radicals by irradiating light in a wavelength region of 365 nm to 405 nm.
The second photoreaction initiator contains at least one of an acylphosphine oxide-based photoreaction initiator or an oxime ester-based photoreaction initiator.
An electric wire with a terminal , which is excited by light in the ultraviolet region and contains a thioxanthone-based sensitizer that enhances radical generation in 365 nm to 405 nm by donating electrons to the first photoreaction initiator . The difference in the curing reaction rate calculated based on infrared light absorption between the coating material on the surface portion and the coating material on the bottom surface side of the terminal on the back side of the conducting wire in the inter-barrel portion is within 3%. The electric wire with a terminal according to claim 1 .

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