JP6677998B2 - Surface protective agent for electric contact, electric contact using the same, and connector - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a surface protective agent for an electrical contact constituted by using a material containing tin, an electrical contact using the same, and a connector.

  A wide variety of electronic devices are mounted on automobiles, industrial machines, optical devices, and precision devices. For example, a wire harness is provided in the above-described electronic device in order to transmit power, control signals, and the like. The wire harness includes a plurality of electric wires and a connector.

  The connector includes a connector terminal and a connector housing. The connector terminal is made of a conductive sheet metal or the like, and is electrically connected to a mating connector.

  Conventionally, a connector terminal generally used is one in which a surface of a base material such as copper or a copper alloy is plated with tin or the like (Patent Document 1).

JP 2008-248294 A

  However, since tin plating and tin alloy plating form a hard oxide film on the surface, there is a problem that fretting wear occurs due to peeling and contact stability is reduced. Then, problems such as contact failure, poor operation, and reduced durability are caused by the reduced contact stability.

  Also, even if an oil agent is interposed between the tin plating and the mating connector, it is difficult to completely eliminate the occurrence of fretting wear. No protective agent was present.

  The invention described in Patent Document 1 discloses a configuration in which lubricating particles are contained in a tin plating surface plating layer.

  However, in a configuration in which the lubricating particles are scattered in the plating layer, there is a problem that the lubricating particles are missing from the surface plating layer due to sliding with the mating connector. Further, as one example of the lubricating particles, application of a capsule containing a lubricant is described (see [0026] of Patent Document 1). It is described that the capsule is crushed by sliding with the mating connector, the lubricant is released, and the lubricant is supplied to the mating connector. However, since it is assumed that the surface plating layer is shaved until the capsule is exposed, the contact stability cannot be sufficiently improved. Further, the supply of the lubricant is premised on the fact that the capsule is crushed, so that it is unstable and the contact stability tends to vary. In addition, in a configuration in which lubricating particles are scattered in the plating layer, an increase in electrical resistance and a variation in electrical resistance are likely to occur, which may affect the electrical conductivity.

  Therefore, the present invention has been made in view of such a problem, and it is an object of the present invention to improve the contact stability of a surface protective agent for an electric contact configured by using a material containing tin, as compared with the related art. It is an object of the present invention to provide a surface protective agent for an electric contact capable of performing the above, an electric contact using the same, and a connector.

The present invention is a surface protective agent for a sliding electric contact configured having a material containing tin, comprising an organotin compound and a solvent, wherein the solvent is at least as a nonflammable solvent A fluorine solvent, wherein the fluorine solvent is hydrofluoroether, hydrofluorocarbon, hydrochlorofluorocarbon, perfluorocarbon, perfluoropolyether, benzotrifluoride, bis (trifluoromethyl) benzene, difluoroacetone, hydrofluoroolefin, and It is characterized by including at least hydrochlorofluoroolefin among hydrochlorofluoroolefins .

  In the present invention, the tin atom of the organotin compound is preferably in a state of 1-substituted tin, 2-substituted tin, or 4-substituted tin.

  In the present invention, the organotin compound is dimethyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, dimethyltin bis (dodecylmercaptide), dibutyltinbis (dodecylmercaptide), dioctyltinbis (dodecylmercaptide), dimethyltin Bis (2-ethylhexyl thioglycolate), dibutyltin bis (2-ethylhexyl thioglycolate), dioctyltin bis (2-ethylhexyl thioglycolate), dimethyltin diacetate, dibutyltin diacetate, dioctyltin diacetate, Dimethyltin maleate, dibutyltin maleate, dioctyltin maleate, dimethyltin bisthioglycerol, dibutyltin bisthioglycerol, dioctyltin bisthioglycerol Lumpur, octyl tin tris (2-ethylhexyl thioglycolate), bis (beta-methoxycarbonylethyl) of tin dilaurate, are preferably selected from at least one kind.

  In particular, in the present invention, the organotin compound preferably contains at least one of dioctyltin dilaurate, dioctyltin bis (2-ethylhexyl thioglycolate), and dioctyltin maleate.

Further, the electrical contact in the present invention has a sliding electrical contact configured with a material containing tin, and a protective layer coated on the surface of the sliding electrical contact, the protective layer, It is formed using the surface protective agent for an electric contact described above, and comprises at least the organotin compound.

Further, the connector according to the present invention has a connector terminal as a sliding electrical contact configured by including a material containing tin, and a protective layer coated on a surface of the connector terminal, wherein the protective layer is It is formed using the surface protective agent for electrical contacts described above, and contains at least the organotin compound.

  ADVANTAGE OF THE INVENTION According to this invention, fretting wear can be suppressed by using the surface protective agent for electric contacts containing an organotin compound. As a result, it is possible to obtain better contact stability than before, and it is possible to suppress problems such as contact failure, malfunction, and deterioration of durability.

FIG. 1A is a partial cross-sectional view showing a part of the connector, and FIG. 1B is a partially enlarged cross-sectional view showing an enlarged area A surrounded by a dotted line in FIG. 1A.

  Hereinafter, one embodiment of the present invention (hereinafter, abbreviated as “embodiment”) will be described in detail. It should be noted that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

  The present inventors have conducted a sincere study on a protective agent for an electrical contact formed using a material containing tin, and as a result, it is possible to suppress fretting wear by using a protective agent containing an organic tin compound. As a result, good contact stability can be obtained as compared with the related art.

(Organotin compounds)
The “organotin compound” is a compound containing a direct bond between a tin atom and a carbon atom constituting an organic group in the compound.

  In the present embodiment, the tin atom of the organotin compound is preferably in a state of 1-substituted tin, 2-substituted tin, or 4-substituted tin. Triorganic-substituted tin is highly toxic and cannot be used due to its effects on the human body and the environment.

When the organotin compound is represented as a chemical formula, it can be represented by RSnX ₃ (monoorganotin), R ₂ SnX ₂ (diorganotin), and R ₄ Sn (tetraorganotin). _Among, R represents indicated by C _{m H 2m,} in the range of m = 10 to 20. X is at least one selected from laurate, acetate, maleate, 2-ethylhexyl thioglycolate, thioglycerol and the like.

  Organotin compounds in the present embodiment include dimethyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, dimethyltinbis (dodecylmercaptide), dibutyltinbis (dodecylmercaptide), dioctyltinbis (dodecylmercaptide), dimethyltinbisbis (2-ethylhexyl thioglycolate), dibutyltin bis (2-ethylhexyl thioglycolate), dioctyltin bis (2-ethylhexyl thioglycolate), dimethyltin diacetate, dibutyltin diacetate, dioctyltin diacetate, dimethyl Suzu maleate, dibutyl tin maleate, dioctyl tin maleate, dimethyl tin bisthioglycerol, dibutyl tin bisthioglycerol, dioctyl tin bisthioglycer Lumpur, octyl tin tris (2-ethylhexyl thioglycolate), bis (beta-methoxycarbonylethyl) of tin dilaurate, are preferably selected from at least one kind.

  At least one of dioctyltin dilaurate (see the following chemical formula 1), dioctyltin bis (2-ethylhexyl thioglycolate) (see the following chemical formula 2), and dioctyltin maleate (see the following chemical formula 3) It is more preferable to include at least one of them.

  In the present embodiment, it is most preferable that at least dioctyltin dilaurate is contained as the organotin compound. Dioctyltin dilaurate is considered to have a very good affinity for tin plating on the surface of a contact (for example, a connector terminal), and as shown in an experiment described later, by using dioctyltin dilaurate as an organic tin compound, It is possible to more effectively improve the contact stability of the connector terminal.

(Solvent type)
The surface protective agent for electric contact of the present embodiment is characterized by containing the above-mentioned organotin compound and a solvent.

  The solvent in this embodiment is preferably an organic solvent capable of forming a uniform solution of the organotin compound. Here, the “homogeneous solution” is a state in which no suspension of the solution or generation of a precipitate has occurred, and can be visually confirmed.

  Here, the organic tin compound is preferably in the range of 0.01 part by weight to 20 parts by weight, when the total amount of the protective agent is 100 parts by weight. If the content of the organotin compound is less than 0.01 parts by weight, the intended effect of achieving contact stability is insufficient even if the organotin compound is contained in the surface protective agent for electric contacts. On the other hand, when the content of the organotin compound exceeds 20 parts by weight, the amount of the organotin compound in the surface protective agent for electric contacts is too large, and it becomes difficult to obtain a uniformly mixed solvent. Even if the content of the tin compound is increased, it is not practical because the intended effect according to the content cannot be further improved and the price becomes expensive. In addition, the content of the organotin compound and the amount of the solvent are, for example, 0.01 to 20 parts by weight of the organotin compound depending on the intended use, such as the required thickness of the protective layer and the use environment. The content can be adjusted appropriately within the range of the content.

  The organic solvent in this embodiment is used as a diluting solvent for the organotin compound. In order to uniformly apply the organotin compound to the contact in a thin film, the organic solvent is preferably volatilized immediately after the application. The boiling point of the organic solvent is preferably 200 ° C. or lower (1 atm), more preferably 150 ° C. or lower, further preferably 130 ° C. or lower, because the drying property is poor when the temperature exceeds 200 ° C. In this embodiment, one kind of solvent may be used, or a plurality of kinds of solvents having different kinds may be used.

  Here, the solvent can be divided into a flammable solvent and a nonflammable solvent. Specific examples of the flammable solvent include aromatic hydrocarbon solvents, alcohol solvents, ester solvents, ether solvents, ketone solvents, glycol ether solvents, alicyclic hydrocarbon solvents, and aliphatic hydrocarbon solvents. It is preferable to select from at least one of a hydrogen-based solvent, an aliphatic or aromatic hydrocarbon mixture. For example, halogenated hydrocarbons are highly toxic to animals and plants, including humans, and thus are not preferably used as the solvent in this embodiment. In addition, dioxins generated when organic substances containing chlorine are burned are persistent organic pollutants, and when released into the environment, have a long-term effect on ecosystems, and are used as solvents in this embodiment. It is not preferable.

  As the aromatic hydrocarbon solvent, for example, toluene, xylene, styrene and the like can be selected.

  Further, the alcohol-based solvent can be selected from, for example, methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, isopentyl alcohol, and the like.

  Further, the ester solvent can be selected from, for example, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, pentyl acetate, isopentyl acetate, and the like.

  The ether solvent can be selected from, for example, ethyl ether, 1,4-dioxane, tetrahydrofuran, and the like.

  The ketone-based solvent can be selected from, for example, acetone, methyl ethyl ketone, methyl butyl ketone, methyl isobutyl ketone, and the like.

  The glycol ether solvent can be selected from, for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol ethyl ether acetate, and the like.

  The alicyclic hydrocarbon-based solvent can be selected from, for example, cyclohexanone, methylcyclohexanone, cyclohexanol, methylcyclohexanol, and the like.

  The aliphatic hydrocarbon solvent can be selected from, for example, normal hexane and the like.

  In addition, the aliphatic or aromatic hydrocarbon mixture can be selected from, for example, petroleum ether, petroleum benzine, and the like.

  In the present embodiment, it is preferable that at least a fluorine solvent be contained as the nonflammable solvent. Specific examples of the fluorine solvent include hydrofluoroether, hydrofluorocarbon, hydrochlorofluorocarbon, perfluorocarbon, perfluoropolyether, benzotrifluoride, bis (trifluoromethyl) benzene, difluoroacetone, hydrofluoroolefin, and hydrofluoroolefin. It is preferable to select from at least one of chlorofluoroolefins.

  From the viewpoints of compatibility with the organotin compound, global warming potential, and ozone depletion potential, it is preferable to select at least a hydrochlorofluoroolefin from the above-mentioned fluorine solvents. As shown in the experiments described later, by using hydrochlorofluoroolefin as the nonflammable organic solvent, it is possible to more effectively improve the contact stability of the connector terminal as a contact.

  The preferred range of the content of the organic tin compound in the solvent and the preferred range of the boiling point of the organic solvent are the same whether the organic solvent is a flammable organic solvent or a nonflammable organic solvent.

(Lubricant type, grease type)
The surface protective agent for an electric contact according to the present embodiment is characterized by containing the above-described organotin compound and a lubricating oil or a lubricating component of grease. That is, the lubricating oil type includes an organotin compound and a lubricating oil as a lubricating component. The grease type includes an organotin compound, a base oil as a lubricating component, and a thickener.

  Here, the organic tin compound is preferably in the range of 0.01 part by weight to 20 parts by weight, when the total amount of the protective agent is 100 parts by weight. If the content of the organotin compound is less than 0.01 parts by weight, the intended effect of achieving contact stability is insufficient even if the organotin compound is contained in the surface protective agent for electric contacts. Further, when the content of the organotin compound exceeds 20 parts by weight, the amount of the organotin compound in the surface protective agent for electric contacts is too large, and the lubricating performance is reduced. Is not practical because the desired effect according to the content cannot be further improved, and the price becomes high. In addition, the content of the organotin compound and the amount of the lubricating component can be appropriately adjusted within the range of 0.01 to 20 parts by weight of the organotin compound depending on the intended use. .

  The lubricating component is preferably selected from at least one of mineral oil, synthetic hydrocarbon oil, diester oil, polyol ester oil, ether oil, glycol oil, silicone oil, and fluorine oil. These lubricating components can be used alone or in combination of two or more, and the amount used is not particularly limited, and the amount can be selected according to the suitability for application. As the lubricating component, poly-α-olefins and ethylene α-olefin oligomers are particularly preferred in view of their ability to be used in a wide temperature range, compatibility with rubbers and resins, and compatibility with additives.

  Thickeners contained in the grease of the present embodiment include lithium soap, calcium soap, sodium soap, aluminum soap, lithium complex soap, calcium complex soap, aluminum complex soap, urea compound, organic bentonite, polytetrafluoroethylene, It is preferable to select from at least one of silica gel and sodium terephthalamate. The thickener is preferably lithium stearate and / or lithium 12-hydroxystearate from the viewpoint of shear stability. Lithium soap is a saponification product of a fatty acid or a derivative thereof with lithium hydroxide. The fatty acid used is at least one selected from the group consisting of saturated or unsaturated fatty acids having 2 to 22 carbon atoms and derivatives thereof. Further, "soap" obtained by reacting the above-mentioned fatty acid or its derivative with lithium hydroxide is commercially available, and can be used.

  If necessary, an antioxidant, a rust inhibitor, a metal corrosion inhibitor, an oil agent, an antiwear agent, an extreme pressure agent, a solid lubricant, and the like can be added. The content of these additives is within the range of about 0.01 to 20 parts by weight. The antioxidant can be selected from hindered phenol, alkylated diphenylamine, phenyl-α-naphthylamine and the like. The rust inhibitor can be selected from carboxylic acids such as stearic acid, dicarboxylic acids, metal soaps, carboxylic acid amine salts, metal salts of heavy sulfonic acids, carboxylic acid partial esters of polyhydric alcohols, and the like. The metal corrosion inhibitor can be selected from benzotriazole or benzimidazole. The oil agent may be selected from amines such as laurylamine, higher alcohols such as myristyl alcohol, higher fatty acids such as palmitic acid, fatty acid esters such as methyl stearate, and amides such as oleylamide. it can. The antiwear agent can be selected from zinc-based, sulfur-based, phosphorus-based, amine-based, ester-based, and the like. The extreme pressure agent may be selected from zinc dialkyldithiophosphate, molybdenum dialkyldithiophosphate, sulfurized olefin, sulfurized fat, methyltrichlorostearate, chlorinated naphthalene, iodinated benzyl, fluoroalkylpolysiloxane, or lead naphthenate, etc. Can be. The solid lubricant can be selected from graphite, fluorinated graphite, polytetrafluoroethylene, melamine cyanurate, molybdenum disulfide, antimony sulfide, and the like.

(connector)
FIG. 1A is a partial cross-sectional view showing a part of the connector, and FIG. 1B is a partially enlarged cross-sectional view showing an enlarged range A surrounded by a dotted line in FIG. 1A.

  As shown in FIG. 1A, the connector 1 includes a male connector 2 and a female connector 3. The male connector 2 includes a resin housing 4 and a metal male terminal (connector terminal) 5. The female connector 3 includes a resin housing 6 and female terminals (connector terminals) 7. For example, a part of the female terminal 7 is configured by a leaf spring structure 7a. FIG. 1A shows a state where the male connector 2 is inserted into the female connector 3, and the male terminal 5 of the male connector 2 and the female terminal 7 of the female connector 3 are in electrical contact.

  As shown in FIG. 1B, the male terminal 5 has a base material 10, a surface plating layer 11 formed on the surface of the base material 10, and a protective layer 12 formed on the surface of the surface plating layer 11. Be composed.

  It does not matter what the material of the base material 10 is, but depending on the mechanical strength, heat resistance, conductivity, etc., for example, copper alloys such as phosphor bronze and beryllium copper, pure iron, iron alloys such as stainless steel, nickel alloys And so on.

  The surface plating layer 11 is a plating layer containing tin, and may be made of tin alone or a tin alloy. The surface plating layer 11 only needs to have a tin plating layer exposed on the surface, and for example, may have a laminated structure with a silver plating layer or the like.

  The protective layer 12 is a layer configured to include the organotin compound according to the present embodiment. The thickness of the protective layer 12 is about several μm to several hundred μm, and the thickness can be adjusted according to the intended use. For example, when the organotin compound is directly applied to the surface of the surface plating layer 11, the thickness of the protective layer 12 is about several tens μm to several hundred μm. In the case of the solvent type, when a protective agent is applied to the surface of the surface plating layer 11, the solvent is volatilized, so that the protective layer 12 can be formed to be thin and several μm to several μm depending on the content of the organotin compound. Various adjustments can be made in units of 10 μm. Note that the volatilization state differs depending on the solvent used, and some volatilize in a few minutes. In some cases, a drying step is performed to accelerate the removal of the solvent. In the case of the lubricating oil type and the grease type, since the lubricating component remains on the surface of the surface plating layer 11, the film thickness of the protective layer 12 is larger than that of the above-mentioned solvent type, although it depends on the amount of application. It is about μm to several hundred μm.

  The protective layer 12 may be formed on the entire surface of the surface plating layer 11 as shown in the drawing, or may be formed partially. The term “partial” refers to a lattice shape, a sea stripe shape (for example, a dot shape), a stripe shape, or the like, and a portion where the protective layer 12 is not provided on the surface plating layer 11. Thus, even if the protective layer 12 is partially provided, the tin surface can be properly protected, and the conductivity and the insertion / extraction property can be improved as compared with the conventional product. The thickness of the protective layer 12 is measured by an average thickness. For example, the thickness of the protective layer 12 is measured at a plurality of points (at least three points) on the protective layer 12 using a stylus-type surface shape measuring instrument or an ultrasonic method, and the arithmetic average is obtained. It is shown as the value obtained.

  The surface protective agent (organic tin compound alone, solvent type, lubricating oil type, and grease type) in the present embodiment is used for an electrical contact configured with a material containing tin, As a result, the tin surface can be appropriately protected, that is, the peeling of the surface plating layer 11 can be prevented even by repeated insertion and removal of the terminal, so that fretting wear can be suppressed, and the contact stability between the male terminal 5 and the female terminal 7 can be reduced. Can be improved as compared with the related art. Specifically, as shown in the experimental results described later, it is possible to improve conductivity and insertion / extraction properties as compared with conventional products.

  Although FIG. 1B shows the cross-sectional structure of the male terminal 5, the surface protective agent in the present embodiment may be applied to at least one of the male terminal 5 and the female terminal 7.

  The presence or absence of the present invention can be determined by analyzing the protective agent traded in the distribution process. The presence or absence of the present embodiment can also be determined by analyzing the protective layer formed on the terminal surface of the connector. At this time, in the case of the solvent type, the solvent is volatilized and does not exist in the protective layer, but it is possible to infer the use of the solvent type from the thickness of the protective layer.

  In the above description, a connector is described as an example of the electrical contact, but the surface protective agent of the present embodiment is not limited to a connector terminal. Examples of the contact include a terminal of a switch, a PC card, and the like in addition to the connector terminal. Note that the surface protective agent of the present embodiment is effectively applied to connector terminals.

  Hereinafter, the present invention will be described in detail with reference to examples implemented to clarify the effects of the present invention. In addition, this invention is not limited at all by the following Examples.

  Example 1 to Example 8, Reference Example 1, Reference Example 2, and Conventional Example were prepared with the formulations shown in Tables 1 and 2 below. The raw materials used are as follows.

(Example 1)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 100 parts by weight (Example 2)
Organotin compound Dioctyltin dilaurate (C ₄₀ H ₈₀ O ₄ Sn): 1.0 part by weight Flammable solvent normal hexane (boiling point 69 ° C.): 99.0 parts by weight (Example 3)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 1.0 part by weight of flammable solvents Exxsol D40 (boiling point 166 ° C.): 99.0 parts by weight (Example 4)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 1.0 part by weight of nonflammable solvent hydrochlorofluorocarbon fluoroolefin (Central Glass Ltd. model number: 1233Z): 99.0 parts by weight (Example 5)
Organotin compound dioctyltin dilaurate (C ₄₀ H ₈₀ O ₄ Sn): 0.01 part by weight Nonflammable solvent Hydrochlorofluoroolefin (manufactured by Central Glass: Model No .: 1233Z): 99.99 parts by weight (Example 6)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 1.0 part by weight of lubricant (base oil) poly α-olefin (kinematic viscosity (40 ^℃): 30mm 2 /s):99.0 parts ( Example 7)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 0.01 parts by weight lubricant (base oil) poly α-olefin (kinematic viscosity (40 ^℃): 30mm 2 /s):99.99 parts ( Example 8)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 1.0 part by weight of the base oil poly α-olefin (kinematic viscosity (40 ^℃): 30mm 2 /s):89.0 parts Thickener Lithium soap (Lithium 12-hydroxystearate): 10.0 parts by weight (Reference Example 1)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 0.005 parts by weight nonflammable solvent hydrochlorofluorocarbon fluoroolefin (Central Glass Ltd. model number: 1233Z): 99.995 parts by weight (see Example 2)
Organotin compounds of dioctyltin dilaurate _{(C 40 H 80 O 4 Sn} ): 0.005 parts by weight base oil poly α-olefin (kinematic viscosity (40 ^℃): 30mm 2 /s):89.995 parts Thickener Lithium soap (Lithium 12-hydroxystearate): 10.0 parts by weight (conventional example)
Amine-based rust inhibitor 2.0 parts by weight Amine-based antioxidant: 2.0 parts by weight Organic acid oiliness improver: 2.0 parts by weight High-viscosity synthetic hydrocarbon oil: 94.0 parts by weight

  For Examples 2 to 7 and Reference Example 1, each raw material was weighed and mixed with stirring to obtain a uniform solution. In Example 8 and Reference Example 2, lithium soap was synthesized in the presence of a base oil, and the temperature was increased while stirring. Next, after cooling to 80 ° C. or lower, dioctyltin dilaurate was formulated, and a uniform grease composition was obtained by using a three-roll mill, a disper mill, a colloid mill or the like. The blending consistency is NLGI No. It was adjusted in two grades. The test method is based on JIS K2220.

  As an evaluation method, a connector was attached to a desktop vibration tester, a vibration was applied at a frequency of 100 Hz, 2G, and room temperature for 96 hours, and the conductivity at that time was measured with an oscilloscope. The case where the conductivity was good was rated as ○, the case where the conductivity was slightly unstable was rated as △, and the case where the conductivity was unstable was rated as x. Further, as an insertion / extraction test, insertion / extraction was performed 100 times, and the presence or absence of sliding wear at that time was confirmed.場合 indicates no wear, ○ indicates slight wear, and × indicates wear. In the experiment, model numbers: 7282-5976 ASSY and 7283-5976 ASSY manufactured by Yazaki Corporation were used as connectors. This connector is tin-plated as a surface plating layer. Tables 1 and 2 show the evaluation test results.

  As shown in Table 1, in Examples 1 to 8, dioctyltin dilaurate was contained as an organotin compound, and there was no problem in the electrical conductivity because fretting wear was suppressed. It was found that no dynamic wear occurred.

  Further, as shown in Example 5, when the amount of the organotin compound is 0.01 parts by weight or more, even if the organic solvent or the fluorine solvent as the nonflammable solvent is completely volatilized, the coating film thickness is sufficiently ensured. Therefore, it was found that the effects (conductivity, insertion / extraction) of the addition of the organotin compound were sufficient. In the solvent type, when the organic tin compound is added in an amount of 1.0 part by weight, the protective layer has a thickness of about 1 μm to 10 μm. The thickness was about 0.01 μm to 1 μm. Incidentally, the thickness of the protective layer in Example 1 was about 10 μm to 100 μm.

  In addition, in Example 7 as a lubricating oil type, it was found that if the organic tin compound was 0.01 parts by weight or more in the base oil, the effect of the addition of the organic tin compound was sufficient. The same applies to the grease type.

  Reference Example 1 and Reference Example 2 contained an organotin compound, and were found to have somewhat better electrical conductivity and insertion / extraction properties than the conventional example. Therefore, Reference Example 1 and Reference Example 2 are also one of the examples, but resulted in inferior electrical conductivity and insertion / extraction property as compared with Examples 1 to 8 described above.

  This is because, in Reference Example 1, the content of the organotin compound is 0.005 parts by weight, so that when the fluorine solvent as the organic solvent or the nonflammable solvent is completely volatilized, an appropriate coating film thickness is secured. Due to the inability to do so.

  Similarly, in Reference Example 2, the content of the organotin compound was 0.005 parts by weight, and thus the amount of the organotin compound contained in the lubricant was too small. Expression was somewhat poor.

  The conventional example is a commercially available protective agent.Unlike the examples, the organotin compound is not formulated, so that fretting wear occurs, resulting in non-conduction, and in the insertion and removal test, sliding wear occurs. I found out.

  The surface protective agent for an electric contact in the present invention can be used as a surface protective agent for an electric contact composed of a material containing tin. In the present invention, for example, it can be used as a protective agent for a tin-containing connector used in automobiles, industrial machines, optical instruments, precision instruments, and the like. In particular, it can be applied stably even in fields where the acceptance criteria for contact stability are very high, such as automobiles.

1 Connector 2 Male Connector 3 Female Connector 5 Male Terminal (Connector Terminal)
7 Female terminal (connector terminal)
Reference Signs List 10 base material 11 surface plating layer 12 protective layer

Claims (6)

A surface protective agent for a sliding electrical contact configured with a material containing tin, comprising an organic tin compound and a solvent,
The solvent contains at least a fluorine solvent as a nonflammable solvent,
The fluorinated solvent includes hydrofluoroether, hydrofluorocarbon, hydrochlorofluorocarbon, perfluorocarbon, perfluoropolyether, benzotrifluoride, bis (trifluoromethyl) benzene, difluoroacetone, hydrofluoroolefin, and hydrochlorofluoroolefin. Among them, a surface protective agent for an electrical contact , comprising at least a hydrochlorofluoroolefin .   2. The surface protective agent for an electrical contact according to claim 1, wherein the tin atom of the organotin compound is in a state of one-substituted tin, two-substituted tin, or four-substituted tin. 3.   The organic tin compounds include dimethyltin dilaurate, dibutyltin dilaurate, dioctyltin dilaurate, dimethyltinbis (dodecylmercaptide), dibutyltinbis (dodecylmercaptide), dioctyltinbis (dodecylmercaptide), dimethyltinbis (thioglycolic acid) 2-ethylhexyl), dibutyltin bis (2-ethylhexyl thioglycolate), dioctyltin bis (2-ethylhexyl thioglycolate), dimethyltin diacetate, dibutyltin diacetate, dioctyltin diacetate, dimethyltin maleate, Dibutyltin maleate, dioctyltin maleate, dimethyltin bisthioglycerol, dibutyltin bisthioglycerol, dioctyltin bisthioglycerol, octyl 3. For electrical contacts according to claim 1 or 2, wherein at least one of dutris (2-ethylhexyl thioglycolate) and bis (β-methoxycarbonylethyl) tin dilaurate is selected. Surface protective agent.   The electric contact surface according to claim 3, wherein the organic tin compound contains at least one of dioctyltin dilaurate, dioctyltin bis (2-ethylhexyl thioglycolate), and dioctyltin maleate. Protective agent. A sliding electrical contact configured with a material containing tin,
A protective layer coated on the surface of the sliding electrical contact,
The electrical contact, wherein the protective layer is formed using the surface protective agent for an electrical contact according to any one of claims 1 to 4 , and contains at least the organotin compound. A connector terminal as a sliding electrical contact configured with a material containing tin,
A protective layer coated on the surface of the connector terminal,
The protective layer is formed using an electrical contact surface protection agent according to any one of claims 1 to 4, at least, the connector characterized by comprising said organic tin compound.

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