Patent Application
20220127469
The present application is based on, and claims priority from the prior Japanese Patent Application No. 2020-180518, filed on Oct. 28, 2020, the entire contents of which are incorporated herein by reference.
The present disclosure relates to an anti-corrosive material, a wire with a terminal, and a wire harness.
In recent years, use of aluminum in a coated wire constituting a wire harnesses has been increasing to reduce a weight of a vehicle and thus increase the fuel efficiency of the vehicle. Further, a metal terminal to be connected to such a coated wire is usually formed of copper or a copper alloy having excellent electrical properties. However, when different materials are used for a conductor of the coated wire and the metal terminal, corrosion of a joint between the conductor and the metal terminal is easily caused. Thus, an anti-corrosive material is required to prevent corrosion of the joint.
Japanese Unexamined Patent Application Publication No. 2011-103266 discloses a coated wire with a terminal formed of an anti-corrosive material containing a thermoplastic polyamide resin as a main component, and having a tensile shear strength of 6 N/mm2 or greater for a bundle of aluminum, an elongation rate of 100% or greater, and a moisture absorbing rate of 1.0% or less. A thermoplastic polyamide resin has a relatively long curing time, and hence an attention has been paid to a ultraviolet curable resin that requires only a short-term curing processing. The ultraviolet curable resin is cured instantaneously through irradiation with ultraviolet light, and a washing step or a drying step is not required. Thus, subsequent steps can be performed immediately, and the process can be shortened.
Here, when the anti-corrosive material is not applied to an accurate part in a step of applying the anti-corrosive material to the joint between the conductor and the metal terminal, corrosion may be caused at the joint. Thus, it is required to determine and grasp the part to which the anti-corrosive material is applied. However, the anti-corrosive material formed of the ultraviolet curable resin is colorless and transparent, or is light-colored and transparent. Thus, it is difficult to determine the part to which the anti-corrosive material is applied with visual observation or an identification device including a camera, which is problematic.
The present disclosure has been achieved in view of the above-mentioned problem in such a related-art. Further, the present disclosure has an object to provide an anti-corrosive material that enables accurate determination of an application part. Further, the present disclosure has an object to provide a wire with a terminal that includes an anti-corrosive material, and a wire harness.
An anti-corrosive material according to an aspect of the present disclosure includes an ultraviolet curable resin including a polymerizable compound and a photopolymerization initiator. The polymerizable compound includes at least one of a photopolymerizable (meth)acrylate monomer or a photopolymerizable (meth)acrylate oligomer, and the photopolymerization initiator contains at least one of an aminoalkylphenon-based photopolymerization initiator or an acylphosphine oxide-based photopolymerization initiator. The polymerizable compound includes a combination of a monofunctional (meth)acrylate monomer and a bifunctional (meth)acrylate monomer, or a combination of at least one of a monofunctional (meth)acrylate monomer or a bifunctional (meth)acrylate monomer and at least one of a trifunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer having four or more functional groups. When being irradiated with excitation light with a wavelength falling within a range from 365 nm to 415 nm, the ultraviolet curable resin emits visible light having a wavelength longer than that of the excitation light. The anti-corrosive material has a viscosity of 18,900 mPa·s or less, the viscosity being measured at 25° C. according to JIS Z8803.
According to the present disclosure, there can be provided the anti-corrosive material that enables accurate determination of an application part. Further, according to the present disclosure, there can be provided the wire with a terminal that includes the anti-corrosive material, and the wire harness.
Now, with reference to the drawings, an anti-corrosive material, a wire with a terminal, and a wire harness according to the present embodiment are described. Note that dimensional ratios in the drawings are overdrawn for convenience of description, and may be different from actual dimensional ratios in some cases.
the anti-corrosive material according to the present embodiment covers a joint constituted of different metal parts so as to prevent entrance of corroding substances, and thus prevents corrosion of the joint for a long time period. Further, the anti-corrosive material according to the present embodiment contains an ultraviolet curable resin.
A resin containing, as a main component, a polymerizable compound including at least one of a photopolymerizable (meth)acrylate monomer or a photopolymerizable (meth)acrylate oligomer is used as the ultraviolet curable resin. However, a resin containing, as a main component, a polymerizable compound including a photopolymerizable (meth)acrylate monomer is preferably used. Further, a resin containing, as a main component, a polymerizable compound including both a photopolymerizable (meth)acrylate monomer and a photopolymerizable (meth)acrylate oligomer is further preferably used as the ultraviolet curable resin. When the acrylate-based polymerizable compound described above is used as the ultraviolet curable resin, a sealing member obtained by curing the resin has a high adhesive force, and has excellent weather resistance and impact resistance. Thus, corrosion of the joint can be prevented.
Here, the photopolymerizable (meth)acrylate monomer and the photopolymerizable (meth)acrylate oligomer each have a functional group having a carbon-carbon unsaturated bond. Further, the photopolymerizable (meth)acrylate monomer is categorized into a monofunctional (meth)acrylate monomer having one functional group, a bifunctional (meth)acrylate monomer having two functional groups, a trifunctional (meth)acrylate monomer having three functional groups, and polyfunctional (meth)acrylate monomer having four or more functional groups. Further, the photopolymerizable (meth)acrylate oligomer is categorized into a monofunctional (meth)acrylate oligomer having one functional group, a bifunctional (meth)acrylate oligomer having two functional groups, a trifunctional (meth)acrylate oligomer having three functional groups, and polyfunctional (meth)acrylate oligomer having four or more functional groups.
As the monomer contained in the ultraviolet curable resin, at least one of a trifunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer is used instead of a monofunctional (meth)acrylate monomer and a bifunctional (meth)acrylate monomer. In this case, a cross linking density of a cured object tends to increase after curing the resin. For this reason, such a cured object obtained by curing the ultraviolet curable resin has improved strength and hardness, and also has high surface curability (tackiness). However, due to the trade-off, the cured object has reduced elongation and depth curability, and the cured object to be obtained disadvantageously peels off. Thus, it is difficult to prevent corrosion for a long time period.
For this reason, in the polymerizable compound of the ultraviolet curable resin of the present embodiment, a monofunctional (meth)acrylate monomer and a bifunctional (meth)acrylate monomer are used in combination. Alternatively, in the polymerizable compound, at least one of a monofunctional (meth)acrylate monomer or a bifunctional (meth)acrylate monomer and at least one of a trifunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer having four or more functional groups are used in combination. When a (meth)acrylate compound having a small number of functional groups and a (meth)acrylate compound having a large number of functional groups are mixed instead of using only a polyfunctional (meth)acrylate monomer having three or more functional groups, the cross linking density of the cured object to be obtained can be prevented from increasing excessively. For this reason, the cured object to be obtained can have improved elongation and depth curability in addition to strength, hardness, and surface curability. As a result, the cured object to be obtained can be prevented from peeling off at the joint formed of different materials, and can prevent corrosion of the joint for a long time period. Note that depth curability is an index indicating a depth at which the resin is cured when being irradiated with light from above. Further, throughout the specification, the term “(meth)acrylate” includes both acrylate and methacrylate.
Usable monofunctional acrylate monomers are compounds represented by Chemical Formula 1. Specific examples thereof include ethoxylated o-phenylphenol acrylate (see Chemical Formula (a), viscosity: 150 mPa·s at a temperature of 25° C.), methoxypolyethylene glycol 400 acrylate (see Chemical Formula (b), where n=9, viscosity: 28 mPa·s at a temperature of 25° C.), methoxypolyethylene glycol 550 acrylate (see Chemical Formula (b), where n=13), phenoxypolyethylene glycol acrylate (see Chemical Formula (c), viscosity: 16 mPa·s at a temperature of 25° C.), 2-acryloyloxyethyl succinate (see Chemical Formula (d), viscosity: 180 mPa·s at a temperature of 25° C.), and isostearyl acrylate (see Chemical Formula (e), viscosity: 18 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd. Further, other examples of the monofunctional acrylate monomer include β-carboxyethyl acrylate (viscosity: 75 mPa·s at a temperature of 25° C.), isobornyl acrylate (viscosity: 9.5 mPa·s at a temperature of 25° C.), octyl/decyl acrylate (viscosity: 3 mPa·s at a temperature of 25° C.), ethoxylated phenyl acrylate (EO: 2 mol) (viscosity: 20 mPa·s at a temperature of 25° C.), and ethoxylated phenyl acrylate (EO: 1 mol) (viscosity: 10 mPa·s at a temperature of 25° C.) produced by DAICEL-ALLNEX LTD.
Usable bifunctional acrylate monomers are compounds represented by Chemical Formula 2-1 to Chemical Formula 2-3. Specific example thereof include 2-hydroxy-3-(acryloyloxy)propyl methacrylate (see Chemical Formula (a), viscosity: 44 mPa·s at a temperature of 25° C.), polyethylene glycol 200 diacrylate (see Chemical Formula (b), n=4, viscosity: 22 mPa·s at a temperature of 25° C.), polyethylene glycol 400 diacrylate (see Chemical Formula (b), n=9, viscosity: 58 mPa·s at a temperature of 25° C.), polyethylene glycol 600 diacrylate (see Chemical Formula (b), n=14, viscosity: 106 mPa·s at a temperature of 25° C.), polyethylene glycol 1000 diacrylate (see Chemical Formula (b), n=23, viscosity: 100 mPa·s at a temperature of 40° C.), propoxylated ethoxylated bisphenol A diacrylate (see Chemical Formula (c), viscosity: 500 mPa·s at a temperature of 25° C.), ethoxylated bisphenol A diacrylate (see Chemical Formula (d), viscosity: 1500 mPa·s at a temperature of 25° C.), 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene (see Chemical Formula (e), viscosity: 91,000 mPa·s at a temperature of 60° C.), propoxylated bisphenol A diacrylate (see Chemical Formula (f), viscosity: 3000 mPa·s at a temperature of 25° C.), tricyclodecane dimethanol diacrylate (see Chemical Formula (g), viscosity: 120 mPa·s at a temperature of 25° C.), 1,10-decanediol diacrylate (see Chemical Formula (h), viscosity: 10 mPa·s at a temperature of 25° C.), 1,6-hexanediol diacrylate (see Chemical Formula (i), viscosity: 8 mPa·s at a temperature of 25° C.), 1,9-nonanediol diacrylate (see Chemical Formula (j), viscosity: 8 mPa·s at a temperature of 25° C.), dipropylene glycol diacrylate (see Chemical Formula (k), viscosity: 8 mPa·s at a temperature of 25° C.), tripropylene glycol diacrylate (see Chemical Formula (1), m+n=3, viscosity: 12 mPa·s at a temperature of 25° C.), polypropylene glycol 400 diacrylate (see Chemical Formula (1), m+n=7, viscosity: 34 mPa·s at a temperature of 25° C.), polypropylene glycol 700 diacrylate (see Chemical Formula (1), m+n=12, viscosity: 68 mPa·s at a temperature of 25° C.), and polytetramethylene glycol 650 diacrylate (see Chemical Formula (m), viscosity: 140 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd. Further, other examples of the bifunctional acrylate monomer include dipropylene glycol diacrylate (viscosity: 10 mPa·s at a temperature of 25° C.), 1,6-hexanediol diacrylate (viscosity: 6.5 mPa·s at a temperature of 25° C.), tripropylene glycol diacrylate (viscosity: 12.5 mPa·s at a temperature of 25° C.), PO-modified neopentyl glycol diacrylate (viscosity: 20 mPa·s at a temperature of 25° C.), modified bisphenol A diacrylate (viscosity: 1100 mPa·s at a temperature of 25° C.), tricyclodecane dimethanol diacrylate (viscosity: 140 mPa·s at a temperature of 25° C.), PEG 400 diacrylate (viscosity: 60 mPa·s at a temperature of 25° C.), PEG 600 diacrylate (viscosity: 120 mPa·s at a temperature of 25° C.), and neopentyl glycol-hydroxypivalic acid ester diacrylate (viscosity: 25 mPa·s at a temperature of 25° C.) produced by DAICEL-ALLNEX LTD.
Usable trifunctional acrylate monomers and polyfunctional acrylate monomers are compounds represented by Chemical Formula 3-1 to Chemical Formula 3-2. Specific examples thereof include ethoxylated isocyanuric acid triacrylate (see Chemical Formula (a), viscosity: 1,000 mPa·s at a temperature of 50° C.), s-caprolactone modified tris-(2-acryloxyethyl) isocyanurate (see Chemical Formula (b), viscosity: 3,000 to 4,000 mPa·s at a temperature of 25° C.), ethoxylated glycerine triacrylate (EO: 9 mol) (see Chemical Formula (c), l+m+n=9, viscosity: 190 mPa·s at a temperature of 25° C.), ethoxylated glycerine triacrylate (EO: 20 mol) (see Chemical Formula (c), l+m+n=20, viscosity: 110 mPa·s at a temperature of 25° C.), pentaerythritol triacrylate (triester: 37%) (see Chemical Formula (d), viscosity: 790 mPa·s at a temperature of 25° C.), pentaerythritol triacrylate (triester: 55%) (see Chemical Formula (d), viscosity: 490 mPa·s at a temperature of 25° C.), pentaerythritol triacrylate (triester: 57%) (see Chemical Formula (d), viscosity: 730 mPa·s at a temperature of 25° C.), trimethylolpropane triacrylate (see Chemical Formula (e), viscosity: 110 mPa·s at a temperature of 25° C.), ditrimethylolpropane tetraacrylate (see Chemical Formula (f), viscosity: 1,000 mPa·s at a temperature of 25° C.), ethoxylated pentaerythritol tetraacrylate (see Chemical Formula (g), viscosity: 350 mPa·s at a temperature of 25° C.), pentaerythritol tetraacrylate (see Chemical Formula (h), viscosity: 200 mPa·s at a temperature of 40° C.), dipentaerythritol polyacrylate (see Chemical Formula (i), viscosity: 6,500 mPa·s at a temperature of 25° C.), and dipentaerythritol hexaacrylate (see Chemical Formula (j), viscosity: 6,600 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd. Further, examples of the polyfunctional acrylate monomer include dipentaerythritol pentaacrylate, phthalic acid monohydroxyethylacrylate, and isocyanuric acid ethylene oxide modified-diacrylate.
Other examples of the trifunctional acrylate monomer include pentaerythritol (tri/tetra) acrylate (viscosity: 1100 mPa·s at a temperature of 25° C.), trimethylolpropane triacrylate (viscosity: 100 mPa·s at a temperature of 25° C.), trimethylolpropane ethoxytriacrylate (viscosity: 60 mPa·s at a temperature of 25° C.), trimethylolpropane propoxytriacrylate (viscosity: 90 mPa·s at a temperature of 25° C.), and glycerin propoxytriacrylate (viscosity: 100 mPa·s at a temperature of 25° C.) produced by DAICEL-ALLNEX LTD. Other examples of the polyfunctional acrylate monomer having four or more functional groups include pentaerythritol ethoxytetraacrylate (viscosity: 160 mPa·s at a temperature of 25° C.), ditrimethylolpropane tetraacrylate (viscosity: 1,000 mPa·s at a temperature of 25° C.), pentaerythritol (tri/tetra) acrylate (viscosity: 700 mPa·s at a temperature of 25° C.), and dipentaerythritol hexaacrylate (viscosity: 6,900 mPa·s at a temperature of 25° C.) produced by DAICEL-ALLNEX LTD.
Usable monofunctional methacrylate monomers are compounds represented by Chemical Formula 4. Specific examples thereof include 2-methacryloyloxyethyl phthalic acid (see Chemical Formula (a), viscosity: 3,400 mPa·s at a temperature of 25° C.), methoxy polyethylene glycol 400 methacrylate (see Chemical Formula (b), n=9, viscosity: 23 mPa·s at a temperature of 25° C.), methoxy polyethylene glycol 1000 methacrylate (see Chemical Formula (b), n=23, viscosity: 55 mPa·s at a temperature of 40° C.), phenoxy ethylene glycol methacrylate (see Chemical Formula (c), viscosity: 7 mPa·s at a temperature of 25° C.), stearyl methacrylate (see Chemical Formula (d), viscosity: 8 mPa·s at a temperature of 30° C.), and 2-methacryloyloxyethyl succinate (see Chemical Formula (e), viscosity: 160 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd.
Usable bifunctional methacrylate monomers are compounds represented by Chemical Formula 5-1 and Chemical Formula 5-2. Specific examples thereof include ethylene glycol dimethacrylate (see Chemical Formula (a), viscosity: 3 mPa·s at a temperature of 25° C.), diethylene glycol dimethacrylate (see Chemical Formula (b), n=2, viscosity: 5 mPa·s at a temperature of 25° C.), triethylene glycol dimethacrylate (see Chemical Formula (b), n=3, viscosity: 9 mPa·s at a temperature of 25° C.), polyethylene glycol 200 dimethacrylate (see Chemical Formula (b), n=4, viscosity: 14 mPa·s at a temperature of 25° C.), polyethylene glycol 400 dimethacrylate (see Chemical Formula (b), n=9, viscosity: 35 mPa·s at a temperature of 25° C.), polyethylene glycol 600 dimethacrylate (see Chemical Formula (b), n=14, viscosity: 64 mPa·s at a temperature of 25° C.), polyethylene glycol 1000 dimethacrylate (see Chemical Formula (b), n=23, viscosity: 80 mPa·s at a temperature of 40° C.), ethoxylated bisphenol A dimethacrylate (see Chemical Formula (c), viscosity: 1000 mPa·s at a temperature of 25° C.), tricyclodecane dimethanol dimethacrylate (see Chemical Formula (d), viscosity: 100 mPa·s at a temperature of 25° C.), 1,10-decanediol dimethacrylate (see Chemical Formula (e), viscosity: 10 mPa·s at a temperature of 25° C.), 1,6-hexanediol dimethacrylate (see Chemical Formula (f), viscosity: 6 mPa·s at a temperature of 25° C.), 1,9-nonanediol dimethacrylate (see Chemical Formula (g), viscosity: 8 mPa·s at a temperature of 25° C.), neopentyl glycol dimethacrylate (see Chemical Formula (h), viscosity: 5 mPa·s at a temperature of 25° C.), ethoxylated polypropylene glycol 700 dimethacrylate (see Chemical Formula (i), viscosity: 90 mPa·s at a temperature of 25° C.), glycerin dimethacrylate (see Chemical Formula (j), viscosity: 40 mPa·s at a temperature of 25° C.), and polypropylene glycol 400 dimethacrylate (see Chemical Formula (k), viscosity: 27 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd.
Usable trifunctional methacrylate monomers are compounds represented by Chemical Formula 6. Specific examples thereof include trimethylolpropane trimethacrylate (viscosity: 42 mPa·s at a temperature of 25° C.) produced by Shin Nakamura Chemical Co., Ltd.
Further, usable photopolymerizable (meth)acrylate oligomers are aromatic urethane acrylate, aliphatic urethane acrylate, polyester acrylate, and epoxy acrylate produced by DAICEL-ALLNEX LTD. Further, examples of the epoxy acrylate include bisphenol A epoxy acrylate, epoxyfied soybean oil acrylate, modified epoxy acrylate, fatty acid-modified epoxy acrylate, and amine-modified bisphenol A epoxy acrylate.
Examples of the photopolymerizable (meth)acrylate oligomer include acrylic acrylate such as polybasic acid-modified acrylic oligomer, and silicone acrylate.
However, preferred monofunctional (meth)acrylate monomers are isobornyl acrylate and ethoxylated phenylacrylate. Preferred bifunctional (meth)acrylate monomers are 2-hydroxy-3-(acryloyloxy)propyl methacrylate and dipropylene glycol diacrylate. Preferred trifunctional (meth)acrylate monomers are glycerin propoxytriacrylate and trimethylolpropane propoxytriacrylate. Preferred polyfunctional (meth)acrylate monomers having four or more functional groups are pentaerythritol ethoxytetraacrylate and ditrimethylolpropane tetraacrylate.
Note that, in the polymerizable compound of the present embodiment, a mixing ratio of the monofunctional (meth)acrylate monomer, the bifunctional (meth)acrylate monomer, the trifunctional (meth)acrylate monomer, and the polyfunctional (meth)acrylate monomer having four or more functional groups is not limited to Reference Examples and Examples described later, and may be set in a freely-selective manner so as to obtain effects of the present embodiment.
The ultraviolet curable resin according to the present embodiment contains a photopolymerization initiator for accelerating ultraviolet light curing, in addition to the above-mentioned polymerizable compound. The photopolymerization initiator is a compound that initiates a polymerization reaction of the photopolymerizable monomer or the photopolymerizable oligomer. The photopolymerization initiator is a substance that absorbs a light component having a specific wavelength from ultraviolet light, is excited, and then generates radicals.
Here, the ultraviolet curable resin contains at least one of an aminoalkylphenon-based photopolymerization initiator or an acylphosphine oxide-based photopolymerization initiator as the photopolymerization initiator. At least one of the aminoalkylphenon-based photopolymerization initiator or the acylphosphine oxide-based photopolymerization initiator is used as the photopolymerization initiator, and hence the ultraviolet curable resin emits light intensely. Thus, the anti-corrosive material that enables accurate determination of an application position can be obtained.
Specifically, when being dispersed in the polymerizable compound, the aminoalkylphenon-based photopolymerization initiator or the acylphosphine oxide-based photopolymerization initiator absorbs ultraviolet light or violet light with a wavelength falling within a range from 365 nm to 415 nm, and emits visible light having a wavelength longer than that of the ultraviolet light or the violet light. Further, the aminoalkylphenon-based photopolymerization initiator and the acylphosphine oxide-based photopolymerization initiator each include a nitrogen atom or a phosphorus atom in a molecular structure, and hence absorb a larger amount of the ultraviolet light or the violet light and emit light in a highly intense manner. Therefore, when those photopolymerization initiators are used, the ultraviolet curable resin emits visible light in a highly intense manner, the visible light having a wavelength longer than that of the ultraviolet light or the violet light. Thus, the part to which the anti-corrosive material is applied can be determined accurately and easily with visual observation or an identification device including a camera.
A usable aminoalkylphenon-based photopolymerization initiator as described above is 2-benzil-2-(dimethylamino)-4′-morpholinobutyrophenone represented by Chemical Formula 7. Further, usable acylphosphine oxide-based photopolymerization initiators are diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (see Chemical Formula (a)) and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (see Chemical Formula (b)) represented by Chemical Formula 8.
An amount of the photopolymerization initiator added to the ultraviolet curable resin is not particularly limited as long as a polymerization reaction of the polymerizable compound is initiated and promoted. Yet, for example, a mass ratio of the polymerizable compound and the photopolymerization initiator is preferably 100:0.01 to 10.
The ultraviolet curable resin according to the present embodiment contains the above-mentioned polymerizable compound as a main component. Further, the ultraviolet curable resin according to the present embodiment may contain other monomers and oligomers in addition to the above-mentioned polymerizable compound. Moreover, the ultraviolet curable resin may contain at least one of the additives listed below. Usable additives include photopolymerization initiating assistant agents, anti-adhesive agents, fillers, plasticizers, non-reactive polymers, coloring agents, flame retardants, flame retardant assistant agents, anti-softening agents, mold release agents, desiccants, dispersants, wetting agents, anti-settling agents, thickeners, anti-electrification agents, antistatic agents, matting agents, antiblocking agents, anti-skinning agents, and surfactants.
Note that the ultraviolet curable resin may further contain at least one of a fluorescent pigment or a fluorescent dye. Specifically, it is preferred that the ultraviolet curable resin further contain at least one of a fluorescent pigment or a fluorescent dye that emit visible light having a wavelength longer than that of excitation light when the ultraviolet curable resin is irradiated with the excitation light with a wavelength falling within a range from 365 nm to 415 nm. When the fluorescent pigment and/or the fluorescent dye as described above are/is contained, the anti-corrosive material emits light more intensely due to a synergistic effect with the above-mentioned photopolymerization initiator. Thus, the position at which the anti-corrosive material is applied can be determined easily.
The fluorescent pigment and the fluorescent dye that can be added to the ultraviolet curable resin are not particularly limited as long as visible light having a wavelength longer than that of the excitation light can be emitted at the time of irradiation with the excitation light with a wavelength falling within a range from 365 nm to 415 nm. Usable fluorescent pigments are ZnS/Ag (blue), (Zn,Cd)S:Cu (greenish yellow), (Zn,Cd)S:Ag (yellow green), ZnO:Zn (whitish green), ZnS:Cu (green), Y2O2S:Eu (red), ZnS:Cu+Zn2SiO4:Mn (green), Cd2O2S:Tb (yellow green), ZnS:Cd,A1 (yellow green), Y2O2S:Tb (yellow green), ZnS:Ag,Ga,A1 (blue), and the like. Further, usable fluorescent dyes are organic fluorescent dyes such as a diaminostilbene-based dye, an uranine-based dye, a thioflavin-based dye, eosine, and rhodamine B.
As described above, the anti-corrosive material according to the present embodiment contains the above-mentioned ultraviolet curable resin. For this reason, the anti-corrosive material is cured instantaneously through irradiation with ultraviolet light, and a washing step or a drying step is not required. Thus, subsequent steps can be performed immediately, and the process can be shortened. However, in a case where the viscosity of the ultraviolet curable resin is excessively high, when the ultraviolet curable resin is applied to the joint, the application thickness is excessively increased. As a result, the thickness of the coating (sealing member) that is obtained through curing is increased. For this reason, as described later, when a metal terminal is accommodated in a connector housing, the anti-corrosive material cannot be inserted into a cavity of the connector housing. Thus, there may be a risk that an existing connector housing cannot be used.
In view of this, the anti-corrosive material according to the present embodiment has a viscosity of 18,900 mPa·s or less, the viscosity being measured at 25° C. according to JIS Z8803 (the method of measuring a viscosity of a liquid). For this reason, the application thickness can be prevented from being excessively increased, and the thickness of the coating (sealing member) that is obtained through curing is not increased. Thus, an existing connector housing can be used. Note that the minimum value of the viscosity of the anti-corrosive material is not particularly limited, and may be set to 300 mPa·s, for example. When the viscosity of the anti-corrosive material is equal to or greater than this value, dripping during application to the joint is suppressed. Thus, the thickness of the coating that is obtained through curing can be substantially even, and anti-corrosive performance can be improved.
Note that the viscosity of the anti-corrosive material changes depending on a viscosity of each of the photopolymerizable (meth)acrylate monomer and the photopolymerizable (meth)acrylate oligomer, and an added amount of each of the monomer and the oligomer. Further, unless the polymerizable compound is irradiated with ultraviolet light to advance a polymerization reaction, the monomers, and the monomers and the oligomers are not polymerized to increase the viscosity of the polymerizable compound. For this reason, the viscosity of the anti-corrosive material, which is obtained by adjusting the viscosity and the added amount of each of the monomer and the oligomer, can be set to 18,900 mPa·s or less.
As described above, the anti-corrosive material according to the present embodiment includes an ultraviolet curable resin including a polymerizable compound and a photopolymerization initiator. The polymerizable compound includes at least one of a photopolymerizable (meth)acrylate monomer or a photopolymerizable (meth)acrylate oligomer, and the photopolymerization initiator containing at least one of an aminoalkylphenon-based photopolymerization initiator or an acylphosphine oxide-based photopolymerization initiator. The polymerizable compound includes a combination of a monofunctional (meth)acrylate monomer and a bifunctional (meth)acrylate monomer, or a combination of at least one of a monofunctional (meth)acrylate monomer or a bifunctional (meth)acrylate monomer and at least one of a trifunctional (meth)acrylate monomer or a polyfunctional (meth)acrylate monomer having four or more functional groups. When being irradiated with excitation light with a wavelength falling within a range from 365 nm to 415 nm, the ultraviolet curable resin emits visible light having a wavelength longer than that of the excitation light. Further, the anti-corrosive material has a viscosity of 18,900 mPa·s or less, the viscosity being measured at 25° C. according to JIS Z8803.
In the present embodiment, the ultraviolet curable resin in which the (meth)acrylate monomer having a small number of functional groups and the (meth)acrylate monomer having a large number of functional groups are mixed is used as the anti-corrosive material. For this reason, the cured object to be obtained has an appropriate cross linking density, and hence can have improved elongation in addition to strength, hardness, and surface curability. Further, when the monomer contained in the ultraviolet curable resin is constituted of only a polyfunctional (meth)acrylate monomer having three or more functional groups, depth curability is reduced, the resin in the anti-corrosive material is not sufficiently cured and peels off from the joint, and anti-corrosive performance is reduced in some cases. However, in the present embodiment, the ultraviolet curable resin contains a (meth)acrylate compound having a small number of functional groups. Thus, reduction of depth curability can be suppressed, peeling can be prevented, and anti-corrosive performance can be improved.
Further, the anti-corrosive material includes at least one of an aminoalkylphenon-based photopolymerization initiator or an acylphosphine oxide-based photopolymerization initiator as the polymerization initiator. With this, when being irradiated with the excitation light with a wavelength falling within a range from 365 nm to 415 nm, the anti-corrosive material emits visible light having a wavelength longer than that of the excitation light. Thus, the position at which the anti-corrosive material is applied can be determined easily. Therefore, the anti-corrosive material can be applied accurately to a desired part, and the wire with a terminal capable of suppressing corrosion can be manufactured efficiently.
Further, the anti-corrosive material has a viscosity that is equal to or lower than a predetermined value. Thus, the application thickness is prevented from being excessively increased, and increase in thickness of the coating that is obtained through curing can be prevented. Moreover, the anti-corrosive material is cured instantaneously through irradiation with ultraviolet light, and a washing step or a drying step is not required. Thus, the process can be shortened. Further, in the present embodiment, the anti-corrosive material in a liquid form is applied to the joint, and is irradiated with ultraviolet light and cured. Thus, when the wire and the joint have any shapes, a sealing member excellent in anti-corrosive performance can be formed.
[Wire with Terminal]
Next, a wire with a terminal according to the present embodiment is described. As illustrated in
The metal terminal 20 of the wire with a terminal 1 is a female type, and includes an electrical connection portion 21 at its front part, which is connected to a mating terminal (not shown). The electrical connection portion 21 includes a built-in spring piece engageable with the mating terminal, and has a box-like shape. Moreover, the metal terminal 20 includes a wire connection portion 22 at its rear part. The wire connection portion 22 is connected by crimping with respect to the terminal portion of the wire 10 through intermediation of a connection portion 23.
The wire connection portion 22 includes a conductor press-fitting portion 24 positioned on the front side and a covering member crimping portion 25 positioned on the rear side.
The conductor press-fitting portion 24 on the front side is brought into direct contact with the conductor 11 that is exposed by removing the wire covering member 12 at the terminal portion of the wire 10, and includes a bottom plate portion 26 and a pair of conductor crimping pieces 27. The pair of conductor crimping pieces 27 extend upward from both lateral sides of the bottom plate portion 26, and are bent inward so as to wrap the conductor 11 of the wire 10, thereby crimping the conductor 11 under a close contact state with the upper surface of the bottom plate portion 26. With the bottom plate portion 26 and the pair of conductor crimping pieces 27, the conductor press-fitting portion 24 is formed to have a substantially U-like shape in a cross-sectional view.
Further, the covering member crimping portion 25 on the rear side is brought into direct contact with the wire covering member 12 at the terminal portion of the wire 10, and includes a bottom plate portion 28 and a pair of covering member crimping pieces 29. The pair of covering member crimping pieces 29 extend upward from both lateral sides of the bottom plate portion 28, and are bent inward so as to wrap a part having the wire covering member 12, thereby crimping the wire covering member 12 under a close contact state with the upper surface of the bottom plate portion 28. With the bottom plate portion 28 and the pair of covering member crimping pieces 29, the covering member crimping portion 25 is formed to have a substantially U-like shape in a cross-sectional view. Here, a common base plate portion is formed continuously from the bottom plate portion 26 of the conductor press-fitting portion 24 to the bottom plate portion 28 of the covering member crimping portion 25.
In the present embodiment, as illustrated in
Further, as illustrated in
The sealing member 32 is a cured object obtained by irradiating the anti-corrosive material containing the above-mentioned ultraviolet curable resin with ultraviolet light and curing the anti-corrosive material.
Metal having high conductivity may be used as a material of the conductor 11 of the wire 10. Usable materials include copper, a copper alloy, aluminum, and an aluminum alloy. Further, the surface of the conductor 11 may be subjected to tin plating. However, in recent years, reduction in weight of the wire harness has been demanded. In view of this, aluminum or an aluminum alloy having light weight is preferably used as the conductor 11. For this reason, the conductor 11 preferably includes an elemental wire formed of aluminum or an aluminum alloy.
A resin capable of securing an electric insulation property may be used as a material of the wire covering member 12 configured to cover the conductor 11. For example, a resin containing polyvinyl chloride (PVC) as a main component or an olefin-based resin may be used. Specific examples of the olefin-based resin include polyethylene (PE), polypropylene (PP), an ethylene copolymer, and a propylene copolymer.
Metal having high conductivity may be used as a material (terminal material) of the metal terminal 20. For example, at least one of copper, a copper alloy, stainless steel, copper subjected to tin plating, a copper alloy subjected to tin plating, or stainless steel subjected to tin plating may be used. Further, at least one of copper, a copper alloy, or stainless steel that are subjected to gold plating may be used. Alternatively, at least one of copper, a copper alloy, or stainless steel that are subjected to silver plating may be used. Note that the metal terminal preferably contains copper or a copper alloy.
Next, a method of manufacturing the wire with a terminal according to the present embodiment is described. As illustrated in
Subsequently, the anti-corrosive material 30 is applied to the joint between the metal terminal 20 and the wire 10. At this stage, the method of applying the anti-corrosive material 30 is not particularly limited, and a coating machine of a dispenser type may be used, for example. As illustrated in
Here, as described above, the anti-corrosive material 30 according to the present embodiment has a property of emitting visible light having a wavelength longer than that of the ultraviolet light or the violet light when being irradiated with ultraviolet light or violet light with a wavelength falling within a range from 365 nm to 415 nm. Thus, for example, whether the anti-corrosive material 30 is applied to an appropriate part can be determined through use of a quality determination device.
As illustrated in
The region of the joint between the metal terminal 20 and the wire 10 to which the anti-corrosive material 30 is applied is determined in the following manner. First, ultraviolet light or violet light with a wavelength falling within a range from 365 nm to 415 nm is emitted from the excitation light irradiation lamp 43 to the anti-corrosive material 30. With this, the photopolymerization initiator in the anti-corrosive material 30 absorbs the ultraviolet light or the violet light, and emits visible light having a wavelength longer than that of the ultraviolet light or the violet light. Further, the anti-corrosive material 30 under a light emission state is imaged by the camera 41. After that, the captured image is transmitted from the camera 41 to the quality determination unit 42, and the quality determination unit 42 determines the region to which the anti-corrosive material 30 is applied is satisfactory or poor based on the captured image.
When the result of determination of the quality determination unit 42 shows the region to which the anti-corrosive material 30 is applied is satisfactory, the anti-corrosive material 30 is irradiated with ultraviolet light through use of the ultraviolet light irradiation device 50, as illustrated in
Note that the ultraviolet curable resin is known to cause reaction inhibition when being brought into contact with oxygen through curing. One of the causes of the reaction inhibition is oxygen in the air that reacts with radicals generated by the photopolymerization initiator and eliminates the radicals. With this, a polymerization reaction of the ultraviolet curable resin is reduced, and hence curing of the resin is not sufficiently promoted. For this reason, the ultraviolet curable resin that is less affected by the oxygen curing inhibition is preferably used.
Note that a step of cooling the sealing member 32 may be performed as required after the anti-corrosive material 30 is irradiated with ultraviolet light and cured. Examples of the method of cooling the sealing member 32 include a cooling method in which air is sent and brought into contact with the sealing member 32, for example.
As described above, the wire with a terminal according to the present embodiment includes the sealing member 32 obtained by curing the above-mentioned anti-corrosive material 30 with ultraviolet light. Further, the anti-corrosive material has a viscosity that is equal to or lower than a predetermined value. Thus, the application thickness is prevented from being excessively increased, and increase in thickness of the coating that is obtained through curing can be prevented. As a result, as described later, it is not required to change a pitch dimension of a connector housing. Thus, the wire with a terminal according to the present embodiment can be inserted into a connector housing having a conventional size. For this reason, it is not required to change design of a connector housing for the wire with a terminal according to the present embodiment.
Further, the anti-corrosive material 30 according to the present embodiment has a property of emitting visible light having a wavelength longer than that of the ultraviolet light or the violet light when being irradiated with ultraviolet light or violet light with a wavelength falling within a range from 365 nm to 415 nm. Thus, for example, when the quality determination device is used, inspection on whether the region to which the anti-corrosive material 30 is applied is accurate can be performed automatically.
Next, a wire harness according to the present embodiment is described. The wire harness according to the present embodiment includes the above-mentioned wire with a terminal. Specifically, as illustrated in
On a front surface side of the connector housing 60, a plurality of mating-side terminal mounting portions to which mating terminals (not shown) are mounted are provided. Further, on a back surface side of the connector housing 60, a plurality of cavities 61 are provided. Each of the cavities 61 has a substantially rectangular opening that allows the metal terminal 20 and the sealing member 32 of the wire with a terminal 1 to be mounted therein. Moreover, the opening of each of the cavities 61 is formed to be slightly larger than the cross-section of the metal terminal 20 and the sealing member 32. Further, the metal terminal 20 is mounted to the connector housing 60, and the wire 10 is drawn out from the back surface side of the connector housing 60.
Here, as described above, the anti-corrosive material according to the present embodiment has a viscosity that is equal to or lower than a predetermined value. Thus, the application thickness is prevented from being excessively increased, and increase in thickness of the coating (sealing member) that is obtained through curing can be prevented. For this reason, the width of the sealing member 32 of the wire with a terminal 1 can be set smaller than an opening width W of the cavity 61 of the connector housing 60 into which the metal terminal 20 and the sealing member 32 are inserted. Moreover, the maximum height of the sealing member 32 of the wire with a terminal 1 can be set smaller than an opening height H of the cavity 61 of the connector housing 60.
As described above, the thickness of the sealing member 32 of the present embodiment can be reduced. Thus, it is not required to particularly change the pitch dimension of the connector housing 60. For this reason, the wire with a terminal can be inserted into a connector housing having a conventional size. Thus, it is not required to change design of a connector housing particularly for the wire with a terminal, and a conventional connector housing can be used.
The present embodiment is further described below in detail with Examples, Comparative Examples, and Reference Examples. However, the present embodiment is not limited to those examples.
The following compounds were used as oligomers, monomers, and a photopolymerization initiator when a wire with a terminal in each of the reference examples and reference comparative examples was produced.
First, the monofunctional monomer, the bifunctional monomer, and the photopolymerization initiator were mixed in mass proportions of 90, 10, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material.
Subsequently, aluminum was used as a conductor, and polyvinyl chloride (PVC) was used as a wire covering member to prepare a wire. Moreover, copper subjected to tin plating was used as a terminal material to prepare a metal terminal.
Further, a wire with a terminal in this example was prepared by connecting the wire and the metal terminal with each other, applying the anti-corrosive material to the joint between the metal terminal and the wire, and curing the anti-corrosive material through use of a UV lamp.
The monofunctional monomer, the bifunctional monomer, the trifunctional monomer 1, the polyfunctional monomer, and the photopolymerization initiator were mixed in mass proportions of 20, 5, 5, 5, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The monofunctional monomer, the bifunctional monomer, the trifunctional monomer 1, and the photopolymerization initiator were mixed in mass proportions of 3, 3, 3, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The monofunctional monomer, the bifunctional monomer, the polyfunctional monomer, and the photopolymerization initiator were mixed in mass proportions of 30, 5, 5, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The monofunctional monomer, the trifunctional monomer 1, and the photopolymerization initiator were mixed in mass proportions of 20, 5, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The bifunctional monomer, the polyfunctional monomer, and the photopolymerization initiator were mixed in mass proportions of 5, 5, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The monofunctional monomer and the photopolymerization initiator were mixed in mass proportions of 100 and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The bifunctional monomer and the photopolymerization initiator were mixed in mass proportions of 65 and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The trifunctional monomer and the photopolymerization initiator were mixed in mass proportions of 45 and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The polyfunctional monomer and the photopolymerization initiator were mixed in mass proportions of 5 and 2, respectively, with respect to 100 parts by mass of the oligomer 2 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
The trifunctional monomer, the polyfunctional monomer, and the photopolymerization initiator were mixed in mass proportions of 5, 5, and 2, respectively, with respect to 100 parts by mass of the oligomer 1 to prepare an anti-corrosive material. Except for this, a wire with a terminal in this example was prepared in the same manner as in Reference Example 1.
A viscosity of the anti-corrosive material prepared in each of the reference examples and reference comparative examples was measured at a temperature of 25° C. according to JIS Z8803. Specifically, the viscosity was measured through use of a B-type rotational viscometer (TH-10H) at 50 rpm.
The anti-corrosive performance of the wire with a terminal, which was prepared in each of the reference examples and reference comparative examples, was evaluated based on the measurement method specified in Japanese Industrial Standards JIS C60068-2-11 (Basic Environmental Testing Procedures Part 2: Tests-Test Ka: Salt mist). Specifically, the joint between the conductor and the metal terminal of the wire with a terminal was subjected to a salt mist test. More specifically, the test was performed under the following conditions: a temperature of 35±2° C., relative humidity (RH) of 85% or higher, a concentration of salt water of 5±1%, and the test period of 4 days. After that, whether corrosion (rust) was generated at the joint in each example was determined by visual observation. A case where corrosion was not confirmed was evaluated as “satisfactory”. Otherwise, an evaluation as “poor” was given.
The wire with a terminal in each example was inserted into a connector housing. Whether the sealing member was brought into contact with a circumferential wall of a cavity at the time of insertion into the connector housing was determined by visual observation. A case where the sealing member was not brought into contact with the circumferential wall of the cavity was evaluated as “satisfactory”. Otherwise, an evaluation as “poor” was given. Note that, in this evaluation, a wire ALVSS 2sq was used, and a connector housing 2.3II was used.
The oligomers, the monomers, and the photopolymerization initiator that were used in Reference Examples and Reference Comparative Examples, and the results of viscosities of the anti-corrosive materials, evaluation on anti-corrosive performance, and evaluation on connector housing insertion performance are shown in Table 1 and Table 2.
As shown in Table 1, in Reference Example 1 in which the monofunctional (meth)acrylate monomer and the bifunctional (meth)acrylate monomer were used in combination, the satisfactory results were given in evaluation on anti-corrosive performance and evaluation on connector housing insertion performance. Further, in Reference Examples 2 to 6 in which at least one of the monofunctional (meth)acrylate monomer or the bifunctional (meth)acrylate monomer and at least one of the trifunctional (meth)acrylate monomer or the polyfunctional (meth)acrylate monomer were used in combination, the satisfactory results were also given in evaluation on anti-corrosive performance and evaluation on connector housing insertion performance.
In contrast, in Reference Comparative Examples 1 to 4 in which the monofunctional (meth)acrylate monomer, the bifunctional (meth)acrylate monomer, the trifunctional (meth)acrylate monomer, or the polyfunctional (meth)acrylate monomer was used alone, the insufficient results were given with regard to anti-corrosive performance. Further, in Reference Comparative Example 5 in which the trifunctional (meth)acrylate monomer and the polyfunctional (meth)acrylate monomer were used in combination, the inside of the anti-corrosive material was not sufficiently cured, and the anti-corrosive material peeled off. Thus, the insufficient results were given with regard to anti-corrosive performance. Moreover, the anti-corrosive material in Reference Comparative Example 5 had a high viscosity, and the thickness of the sealing member that was obtained was increased. Thus, the insertion into the connector housing was hindered.
The following compounds were used as oligomers, monomers, and a photopolymerization initiator when an anti-corrosive material in each of the examples and comparative examples was produced.
The oligomer, the monofunctional monomer, the bifunctional monomer, the photopolymerization initiators were mixed in at ratios shown in Table 3. In this manner, the anti-corrosive materials in Examples 1 to 5 and Comparative Examples 1 and 2 were prepared.
The anti-corrosive materials thus obtained as described above in Examples 1 to 5 and Comparative Examples 1 and 2 were irradiated with excitation light through use of a black light, and presence or absence and intensity of emission light emitted from the anti-corrosive materials were observed visually. Note that light having a peak wavelength of 365 nm, 385 nm, 405 nm, or 415 nm was used as the excitation light.
As shown in Table 3, it was confirmed that, when being irradiated with the excitation light having a wavelength of 365 nm, 385 nm, 405 nm, and 415 nm, the anti-corrosive materials in Examples 1 to 5 emitted light intensely. From this fact, it can be understood that, when the aminoalkylphenon-based photopolymerization initiator or the acylphosphine oxide-based photopolymerization initiator is used as the photopolymerization initiator, the anti-corrosive material emits light intensely, which enables accurate and easy determination of the position at which the anti-corrosive material is applied.
In contrast, it was confirmed that, when being irradiated with the excitation light having a wavelength of 365 nm, 385 nm, 405 nm, and 415 nm, the anti-corrosive materials in Comparative Examples 1 and 2 only emitted weak light. Specifically, it was confirmed that, when the hydroxyalkylphenone-based photopolymerization initiator and the benzyl ketal-based photopolymerization initiator without nitrogen or phosphorus in a molecule were used as the photopolymerization initiator, the anti-corrosive material emitted weak light. Thus, when those photopolymerization initiators are used, it is difficult to determine the position at which the anti-corrosive material is applied in an accurate and easy manner.
The present embodiment is described above. The present embodiment is not limited thereto, and various modifications can be made within the scope of the present embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-180518 | Oct 2020 | JP | national |
