JP6265098B2 - Wire Harness - Google Patents

Description

  The present invention relates to a wire harness installed between an inverter and a motor, and more particularly to a wire harness having a mold part in which a silicone-coated electric wire is embedded with a mold resin.

  A wire harness that connects between an inverter and a motor of a hybrid vehicle or an electric vehicle is sometimes called an AC harness. The AC harness has a form in which a connector formed of a mold resin is connected to the end of the covered electric wire. The end of the covered electric wire is formed as a molded part in which the periphery is covered with a mold resin and the covered electric wire is embedded in the mold resin. As the covered electric wire, for example, a silicone covered electric wire using silicone rubber as a covering material is used.

  Silicone rubber is known to be a difficult-to-adhere material, and in general, a silicone-based adhesive is often used as an adhesive. However, since the silicone-based adhesive flows out by molding resin during insert molding, it cannot be applied to molding. Therefore, an adhesive that can be adapted for insert molding is used. However, general adhesives for insert molding have poor adhesion to silicone rubber.

  For example, in order to improve the adhesiveness of the adhesive during insert molding in which silicone rubber and thermoplastic resin are integrated, the primer and adhesive are pretreated by plasma treatment or trojan treatment. A method for applying the coating is known (see, for example, Patent Document 1).

JP2013-244652A

  However, the technique described in Patent Document 1 has a problem in that the pretreatment until the adhesive is applied takes a lot of man-hours and requires many kinds of materials.

  The problem to be solved by the present invention is to solve the above-mentioned problems, and in a wire harness having a mold part in which a silicone-coated electric wire is resin-molded, silicone rubber and mold resin of the silicone-coated electric wire in the mold part It is in providing the wire harness excellent in the adhesiveness between.

In order to solve the above problems, the wire harness of the present invention is
A wire harness having a mold part in which a silicone-coated electric wire whose periphery is covered with an insulating layer containing silicone rubber is embedded with a mold resin,
The mold part is one in which the mold resin and the silicone wire are bonded by an adhesive via a primer layer formed on the surface of the silicone-coated wire,
The adhesive is a polyolefin adhesive containing a polyolefin resin,
The gist of the invention is that the primer layer is formed from a composition containing a metal alkoxide.

  In the wire harness of the present invention, the metal alkoxide of the primer is preferably a titanium alkoxide.

  In the wire harness of the present invention, the mold resin is preferably a polyester resin or a polyamide resin.

  In the wire harness of the present invention, the polyolefin resin of the adhesive is preferably a maleic acid-modified polyolefin resin.

  In the wire harness of the present invention, the silicone rubber of the silicone-coated wire is composed of 10 to 300 parts by weight of an inorganic filler, 0.5 to 30 parts by weight of a crosslinking agent, and 0 to 30 parts by weight of a dye for 100 parts by weight of polydimethylsiloxane. It is preferably formed from a composition containing 1 to 10 parts by mass.

  The wire harness of the present invention includes a mold part in which a silicone-coated electric wire whose conductor is covered with an insulating layer containing silicone rubber is embedded with a mold resin, and the mold part is a surface of the silicone-coated electric wire. The mold resin and the silicone wire are bonded by an adhesive via a primer layer formed on the adhesive layer, the adhesive is a polyolefin adhesive containing a polyolefin resin, and the primer layer is Since it is formed from a composition containing a metal alkoxide, the silicone-coated electric wire of the mold part can be used without performing a surface treatment such as plasma treatment or trojan treatment before the treatment for forming the primer layer on the silicone rubber. Excellent adhesion between the silicone rubber and the mold resin. Harnesses can be obtained.

  Since the wire harness of the present invention does not require surface treatment such as plasma treatment or trojan treatment, the number of man-hours does not increase and the bonding work is easy. Moreover, it is possible to use a polyolefin-type adhesive, without using a silicone adhesive etc. as an adhesive, and it is excellent in workability | operativity.

FIG. 1 is a cross-sectional view showing an example of the wire harness of the present invention. FIG. 2 is an enlarged view of a mold part of the wire harness of FIG.

  Hereinafter, embodiments of the present invention will be described in detail. As shown in FIG. 1, the wire harness 1 of the present invention includes a molded portion 4 in which a silicone-coated electric wire 2 in which a conductor 21 is insulated and coated with a coating layer 22 containing silicone rubber is embedded in a mold resin 5. I have.

  A connection terminal 3 is connected to the end portion of the silicone-coated electric wire 2, and a connection portion between the end portion of the silicone-coated electric wire 2 and the connection terminal 3 is embedded in a connector housing formed from the mold resin 5. , Formed as a molded connector.

  The connector housing is arranged so that the connection portion between the silicone-coated electric wire 2 and the connection terminal 3 is accommodated in a cavity inside the connector housing 3, and is inserted using a molding resin (mold resin 5) such as polybutylene terephthalate. By performing the molding, the connection portion between the silicone-coated electric wire 2 and the connection terminal 3 is embedded in the molding resin.

  FIG. 2 is an enlarged view of a mold part of the wire harness of FIG. As shown in FIG. 2, in the mold part 4, the coating layer 22 of the silicone-coated electric wire 2 is bonded to the connector housing 5 formed from the mold resin with the adhesive 7 through the primer layer 6. The adhesive prevents moisture from entering the inside of the connector housing from the end portion C of the joint surface between the mold resin 5 of the connector housing and the covering material 22 of the covered electric wire 2. In FIG. 1, the description of the primer layer and the adhesive is omitted.

  The present invention is greatly characterized in that the primer composition of the primer layer 6 contains a metal alkoxide. By forming a primer layer using a primer containing a metal alkoxide, the adhesion of the polyolefin-based adhesive to the silicone-coated electric wire 2 could be greatly improved. The metal alkoxide contained in the primer layer 6 is chemically bonded to a hydroxyl group derived from polydimethylsiloxane, silica or the like in the silicone rubber of the coating material 22 of the silicone wire, and modifies the surface of the coating material 22. Since the surface of the covering material 22 of the silicone wire 2 is modified by the primer layer 6, the adhesiveness with the polyolefin adhesive 7 is improved.

  For example, the reactivity of metal alkoxide is very high as titanium alkoxide is about 1000 times more reactive than silane coupling agents. Therefore, it is expected that a significant adhesion improvement effect can be obtained when the primer layer is firmly bonded to the coating material of the silicone-coated electric wire, as compared with the case of using a primer other than the metal alkoxide. Thus, since the adhesiveness between the polyolefin-based adhesive and the silicone rubber of the coating material becomes good, the adhesiveness between the silicone-coated electric wire and the mold resin is improved. Even if a polyolefin-based adhesive is used as the adhesive 7, sufficient adhesion is possible.

  The thickness of the primer layer 6 is not limited as long as the silicone-coated electric wire 2 and the mold resin 5 are sufficiently bonded by the adhesive 7. The preferable thickness of the primer layer 6 is a dry film thickness, which is in the range of 0.1 to 120 μm, and preferably in the range of 5 to 80 μm.

  As the primer composition for forming the primer layer 6, one containing a metal alkoxide as a main component is used. Various metal alkoxides can be used as the metal alkoxide, and examples thereof include titanium alkoxide, zirconium alkoxide, and aluminum alkoxide. It is preferable to use a titanium alkoxide because the metal alkoxide is generally easily available and has a good effect of improving adhesiveness.

  In the primer composition, the metal alkoxide may be used in a monomer state, but it is preferable to use a metal alkoxide oligomer such as a titanium alkoxide oligomer which is reacted with water or the like to form an oligomer. The alkoxide oligomer may be used in combination with a metal chelate such as titanium chelate, a metal acylate such as titanium acylate, or the like during oligomerization. By using a metal alkoxide oligomer, film-forming property, wettability, stability, adhesion, etc. are improved.

As the metal alkoxide, generally available compounds are shown below.
Examples of the titanium alkoxide include tetraisopropyl titanate (TPT), tetranormal butyl titanate (TBT), butyl titanate dimer (DBT), tetraoctyl titanate (TOT), tertiary amyl titanate, tetra tertiary butyl titanate (TTBT), tetra Examples include stearyl titanate (TST).

  Titanium chelates include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, titanium phosphate compound, titanium octylene glycolate, titanium ethylacetoacetate, titanium acetylacetonate, titanium octylene glycolate compound, titanium -1,3-propanedioxybis (ethylacetoacetate), solvent-based chelates such as titanium dodecylbenzenesulfonate, titanium lactate ammonium salt, titanium lactate, titanium triethanolamate, titanium diethanolaminate, titanium aminoethylamino Aqueous chelates such as ethanolate can be mentioned.

  Examples of titanium acylate include titanium isostearate.

  Examples of the zirconium alkoxide include normal propyl zirconate (NPZ) and normal butyl zirconate (NBZ).

  Examples of the zirconium chelate include zirconium tetraacetylacetonate, zirconium monoacetylacetonate, zirconium ethylacetoacetate, zirconyl chloride compound, zirconium lactate ammonium salt and the like.

  Examples of the zirconium acylate include a zirconium octylate compound and zirconium stearate.

  A commercial item can be used for a metal alkoxide oligomer. Commercially available products of titanium alkoxide oligomer include, for example, Matsumoto Fine Chemical Co., Ltd., product names “Orgatics PC-200” (main component is titanium alkoxide oligomer), “Orgatics PC-620” (titanium oligomer + adhesion improver) Etc.

  Components other than metal alkoxide may be added to the primer composition within a range that does not impair adhesiveness or the like.

  The primer composition can be used after being diluted with a solvent in order to adjust the composition to an appropriate viscosity. The solvent is appropriately used depending on the solubility of the metal alkoxide, the film formability, and the like. For example, as the solvent, a common solvent such as methanol, ethanol, alcohol such as 1-butanol or isopropanol, acetone or toluene can be used.

  The mold resin 5 constituting the connector housing is not particularly limited, and various mold resins used for the connector housing of this type of wire harness can be used.

  Specific examples of the mold resin 5 include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polybutylene terephthalate, polyethylene terephthalate and polybutylene terephthalate, and polyamide resins such as various polyamides. The mold resin may be one of the above resins or a mixture of two or more of them.

  The mold resin 5 is preferably a polyester resin or a polyamide resin. As the polyester-based resin, polybutylene terephthalate is preferably used.

  A general additive used for resin molding may be added to the mold resin 5. Examples of the additive include a curing agent, a curing catalyst, an inorganic filler, an antioxidant, a metal deactivator (copper damage inhibitor), an ultraviolet absorber, an ultraviolet masking agent, a flame retardant aid, and a processing aid. Agents (lubricants, waxes, etc.), carbon black, other color pigments, flexibility imparting agents, impact resistance imparting agents, organic fillers, diluents (solvents, etc.), alteration agents, antifoaming agents, leveling An agent etc. can be mentioned. The additive added to the mold resin is preferably one having performances such as weather resistance, heat resistance, and cold resistance in order to provide performance as an AC harness.

  As the adhesive 6 for bonding the silicone-coated electric wire 2 and the mold resin 5, a polyolefin-based adhesive containing a polyolefin-based resin is used. The polyolefin adhesive is a hot melt adhesive. That is, it is melted by heat at the time of molding of the mold resin and bonded to the mold resin.

  The polyolefin resin of the adhesive 6 preferably has a carbonyl group in the polymer main chain or side chain, and examples thereof include maleic acid-modified polyolefin resin.

  In order to manufacture a wire harness, first, the connection terminal 3 is connected to the conductor 21 exposed by peeling off the covering material 22 from the end of the silicone-coated electric wire 2. The connection terminal 3 can be joined to the conductor 21 by crimping, welding, or the like. A primer layer 6 and an adhesive 7 are sequentially formed at predetermined positions that become the mold part 4 of the silicone-coated electric wire 22.

  The primer layer 6 can be formed by applying a primer and drying it at room temperature or by heating. The adhesive 7 can be formed by applying a heat-melted adhesive.

  The connector housing can be formed by insert molding or the like. Specifically, the silicone-coated electric wire 2 provided with the primer layer 6 and the adhesive 7 and the connection terminals 3 are arranged at predetermined positions of the connector housing mold, and the molten mold resin 5 is injected into the mold. Then, molding is performed. After cooling, the connector housing formed from the mold resin 5 is taken out of the mold, and the wire harness 1 having the connector housing in which the connection terminals 3 and part of the silicone wire 2 are embedded in the mold resin 5 is obtained.

  The covering material 22 of the silicone-coated electric wire 2 is formed from a silicone rubber composition containing uncrosslinked silicone rubber and a radical generator such as an organic peroxide as a crosslinking agent. The coating material 22 is formed as a crosslinked silicone rubber by extruding a silicone rubber composition around a conductor to form a coating, and then crosslinking the coated silicone rubber by means of heating or the like.

  You may add additives, such as an inorganic filler and a coloring agent, to the said silicone rubber composition. Examples of such additives include general pigments, fillers, antioxidants, anti-aging agents and the like used for wire covering materials.

  The uncrosslinked silicone rubber used in the silicone rubber composition is either a millable type (heated crosslinked type) that becomes an elastic body by kneading a crosslinking agent and then heated and crosslinked, or a liquid rubber type that is liquid before crosslinking. It may be used. The liquid rubber type silicone rubber includes a room temperature crosslinking type (RTV) capable of crosslinking near room temperature and a low temperature crosslinking type (LTV) capable of crosslinking when heated near 100 ° C. after mixing.

  The silicone rubber composition can be blended with a linear organopolysiloxane as a main raw material (raw rubber) and inorganic fillers such as reinforcing fillers and fillers, dispersion accelerators, color materials, and other additives. .

  Examples of the inorganic filler include calcium carbonate, magnesium hydroxide, titanium oxide, acidic clay, mica, silica, and talc.

  As the color material, various pigments, dyes and the like can be used.

  The silicone rubber composition is, for example, a blend containing 100 parts by mass of polydimethylsiloxane, 10 to 300 parts by mass of an inorganic filler, 0.5 to 30 parts by mass of a crosslinking agent, and 0.1 to 10 parts by mass of a color material. Ratio.

  The conductor 21 of the silicone-coated electric wire 2 is generally made of a copper-based metal such as copper or a copper alloy, but aluminum, magnesium or the like can be used in addition to copper. In addition, the conductor 21 may be added with a metal that is usually widely used as a conductor, such as iron, nickel, magnesium, or silicon, as another metal. The conductor 21 can be a single wire, a plurality of wires, or an assembly of a plurality of wires. The aggregate of the single wires may be a stranded wire.

  The diameter of the conductor 21 of the silicone-coated electric wire 2 and the thickness of the covering material 22 are not particularly limited and can be determined as appropriate. The covering material 22 may be a single layer or may be composed of two or more layers.

  This invention wire harness can be utilized for the wire harness used for a motor vehicle and an electronic / electrical apparatus. It is particularly suitable for applications that require high heat resistance and flame retardancy. For example, it is suitable for high voltage and large current applications such as a power cable connecting an engine and a battery of a hybrid vehicle for electric vehicles or an electric vehicle.

[Examples 1 to 4, Comparative Examples 1 to 6]
A test was conducted on the adhesion between the silicone rubber and the molding resin when using a primer containing a metal alkoxide and when using a primer containing no metal alkoxide. Table 1 shows the configurations of primers and test pieces used in Examples and Comparative Examples. As shown in Table 1, Examples 1-4 used a primer containing a metal alkoxide. In Comparative Examples 1 to 6, a primer containing no metal alkoxide was used. For evaluation of the primer, a silicone rubber plate (manufactured by Kurabe Co., Ltd., size 40 mm × 19.5 mm × 1.6 mmt) is prepared, and after primer treatment on the surface of the silicone rubber using various primers shown in Table 1, primer treatment An adhesive was applied to the surface, and insert molding was performed using a molding resin (resin temperature: 250 ° C., mold temperature: 80 ° C.) to produce a single lap joint test piece for a tensile shear adhesion test. Using this test piece, a tensile shear adhesion test was performed. The test results are shown in Table 1.

  The size of the molding resin used for the test was 30 mm × 10 mm × 2 mm in thickness, and the length of the overlap part, which is a joined part, was 20 mm. As the molding resin, Examples 1 and 2 and Comparative Examples 1 to 6 used polybutylene terephthalate resin (PBT), and Examples 3 and 4 used polyamide resin. Details of the primer application method, the materials used in the examples and comparative examples, and the adhesion test method are as follows.

[Primer application method]
Using a pipetter (trade name “Pippetman P-100” manufactured by M & S Instruments Trading Inc), 20 μL of the primer was dropped onto the surface of the silicone rubber plate of 250 mm ^2. After dropping, the primer was used with the tip of the pipetter. It was applied by spreading. After coating, the film was dried at room temperature (23 ° C., humidity 54%) for 1 hour.

[Adhesive strength test method]
Using the above test piece, the tensile shear bond strength was measured according to JIS S6040. Moreover, it observed and determined the fracture | rupture form of the torn surface after a tensile shear adhesion test. As a result of observation, it was judged as “good” in the case of material destruction and as “poor” in the case of interface destruction. If the adhesive surface breaks down at the interface, water easily penetrates into the mold resin from the interface and the waterproof performance is lowered. Therefore, it is important that the fracture mode is not the interface failure but the material failure.

[Primer composition]
・ Titanium alkoxide 1: Product name “X-1229” (manufactured by Matsumoto Fine Chemical Co., Ltd.) (One-component solvent-type primer mainly composed of titanium alkoxide oligomer, including methanol, 2-propanol, ethyl acetate, etc.)
・ Titanium alkoxide 2: manufactured by Matsumoto Fine Chemical Co., Ltd., trade name “PC-620” (a two-part solvent type primer composed mainly of a titanium alkoxide oligomer, consisting of liquid A and liquid B, 1-butanol, toluene, methanol In the test, A liquid and B liquid were mixed at a mass ratio of 1: 1, and diluted with hexane so as to be 5% by mass to prepare a coating liquid.

・ Phenolic resin: manufactured by Cemedine, trade name “3000PP” (phenolic resin 2 to 10%, solvent: hydrocarbon 80 to 90%, ester 1 to 10%)
・ Polyolefin resin: manufactured by Cemedine Co., Ltd., trade name “PP-7F” (olefin resin 2-10%, solvent: hydrocarbon 80-90%, ester 1-10%)
・ Cyano compound: manufactured by High Pressure Gas Industry Co., Ltd., trade name “Cyanone Primer Z831” (2-5% by mass of cyano compound, solvent: 41-52% by mass of alcohol, 45-50% by mass of hydrocarbon)
The resin was applied as a primer in a commercially available form.

Epoxy silane coupling agent: Product name “A-187” (3-glycidoxypropyltrimethoxysilane) manufactured by Momentive
Amino silane coupling agent: manufactured by Momentive, product name “A-1100” (3-aminopropyltriethoxysilane)
-Maleic acid-based silane coupling agent: manufactured by Momentive, product name "A-1877"
The said silane coupling agent prepared the primer as a 5 mass% hexane solution.

[Molded resin]
・ PBT: Polyplastics, product name "Duranex 330HR"
PA6T: Product name “Zytel HTN51G35EF” (polyphthalamide resin) manufactured by DuPont

〔adhesive〕
・ Modified maleic acid adhesive, manufactured by Toagosei Co., Ltd., product name “PPET1303S”

  As shown in Table 1, since Examples 1-4 used a primer containing a titanium alkoxide oligomer, the adhesive strength was sufficiently high, and the fracture mode was material fracture, which was good. On the other hand, Comparative Examples 1-6 used the primer which does not contain a metal alkoxide, and adhesive strength was low, and the fracture | rupture form was also an interface fracture and was unsatisfactory. Also, Examples 1 and 2 using PBT as mold resin and Examples 3 and 4 using polyamide were good results.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Wire harness 2 Silicone-coated electric wire 21 Conductor 22 Coating material 3 Connection terminal 4 Mold part 5 Mold resin (connector housing)
6 Primer layer 7 Adhesive

Claims (5)

A silicone-coated electric wire in which the periphery of the conductor is insulated and coated with a coating material containing silicone rubber is a wire harness provided with a mold portion embedded in a mold resin,
The mold part is one in which the mold resin and the silicone-coated electric wire are bonded by an adhesive via a primer layer formed on the surface of the silicone-coated electric wire,
The adhesive is a polyolefin adhesive containing a polyolefin resin,
The wire harness, wherein the primer layer is formed from a primer composition containing a metal alkoxide.   The wire harness according to claim 1, wherein the metal alkoxide of the primer composition is a titanium alkoxide.   The wire harness according to claim 1 or 2, wherein the mold resin is a polyester resin or a polyamide resin.   The wire harness according to any one of claims 1 to 3, wherein the polyolefin-based resin of the polyolefin-based adhesive is a maleic acid-modified polyolefin resin.   The silicone rubber of the silicone-coated electric wire contains 10 to 300 parts by mass of an inorganic filler, 0.5 to 30 parts by mass of a crosslinking agent, and 0.1 to 10 parts by mass of a coloring agent with respect to 100 parts by mass of polydimethylsiloxane. The wire harness according to any one of claims 1 to 4, wherein the wire harness is formed from a silicone rubber composition.

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