JPH04160195A - Sealing treating solution and its method - Google Patents

Abstract

PURPOSE:To seal pinholes in an Au series plating layer and to manufacture a connector having excellent corrosion resistance and contacting capacity by treating a connector having the electroplating layer of an Au series metal on an Ni plating film by a sealing treating soln. having a specified compsn. CONSTITUTION:The surface of a connector base metal by a Cu series or ferrous metal is provided with Ni plating as an intermediate layer, on which the electroplating of Au or an Au alloy is applied. Then, press working is executed, and after that, micropinholes in the Au series plating layer are subjected to sealing treatment. As a treating soln., the one obtd. by dissolving, by weight, 0.1 to 3% paraffin wax and respectively one or >= two kinds of compounds selected from >= two kinds among (a) to (e) in an organic solvent such as toluene is used, and, if required, 0.05 to 3% chelate formable ring N compounds and 0.001 to 1% aminic or phenolic oxidation preventing agents are added therein: (a) denotes 0.05 to 3% isostearic acid, oxidized wax and oxidized petrolatum, (b) denotes 0.05 to 3% alkyl substituted naphthalen sulfonates, (c) denotes 0.05 to 3% amines, (d) denotes 0.05 to 3% metallic soap and (e) denotes 0.01 to 3% phthalic acid ester, phosphorous acid ester, glycerol monoester and sorbitane ester.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sealing liquid for gold-plated electrical contacts, a sealing method, and a sealed connector contact. In particular, sealing liquids that provide excellent lubrication, rust prevention, and electrical connectivity for electrical contacts in a stable manner over a long period of time, especially under harsh usage conditions where wear and corrosion progress simultaneously due to repeated insertion and removal and vibration.
The present invention relates to a sealing method and a sealed connector.

[Prior Art] Connectors are the most typical connecting parts for electronic devices, and a wide variety of connectors have been put into practical use. Connectors used in so-called industrial electronic devices that require a high degree of reliability, such as computers and communication equipment, are made of spring copper alloys such as phosphor bronze and beryllium copper, and nickel is used as the metal coating for the contacts. Generally used is a base plating followed by gold plating.

Gold has extremely high corrosion resistance among noble metals, and because it does not form oxides or other films on its surface, it has excellent electrical connectivity and is widely used as a contact metal. However, since gold is expensive, various methods have been adopted to reduce the cost of manufacturing connectors. The typical method is to reduce the thickness of the gold plating, but as the thickness of the gold plating becomes thinner, the number of pinholes in the coating increases exponentially, resulting in a significant decrease in corrosion resistance. . One way to solve this problem is through sealing. That is, attempts were made to treat the gold-plated surface with various inorganic or organic chemicals to close pinholes and improve corrosion resistance.

[Problems to be Solved by the Invention] A pore sealing treatment, particularly a pore sealing treatment using an organic chemical, is excellent in maintaining corrosion resistance while reducing the thickness of a gold plating film. However, conventional sealing liquids were mainly selected from compounds known as rust preventive agents for iron-based metal materials and copper-based metal materials, or they were used for the purpose of lubricating gold-plated contacts even before the use of livestock housing. It was commonly used as a lubricant that was used as a lubricant.

The properties required for sealed gold plating are: ■ Good lubricity, ■ Excellent corrosion resistance, ■ Low and stable contact resistance, ■ Good solderability, and ■ Their characteristics are that they last for a long time under various environments and usage conditions.

However, conventional sealing liquids are not necessarily satisfactory from such a comprehensive viewpoint, and are generally inferior in some quality aspect.

In particular, the quality required of electrical contacts (or connectors) for IC cards, which must guarantee electrical connectivity even after 10,000 insertions and removals, is becoming increasingly sophisticated. However, after being inserted and removed 10,000 times over a long period of time, even if the sealing treatment initially had excellent lubricity, dust and other particles in the atmosphere can form on the sealing film during repeated insertion and removal. There was a problem that it would adhere and accelerate wear.

Furthermore, with the rapid development of electronic equipment in automobiles, so-called car electronics, the number of gold-plated connectors for electronic circuits used in automobiles is increasing.

The contacts of automotive connectors are subject to slight sliding wear caused by vibrations caused by the vehicle body, as well as various corrosive gases in the atmosphere in industrial areas, sea salt particles in coastal areas,
Or exposed to extremely harsh corrosive environments such as snow melting agents in cold regions.

That is, the conventional sealing process has not been able to satisfy the above-mentioned characteristics required for electrical contacts over a long period of time in a harsh environment where wear and corrosion coexist.

An object of the present invention is to provide an improved sealing liquid that can meet such demands and a sealing method using the same, and also to provide a connector treated with the same. That is.

[Means for Solving the Problems] In view of this situation, the inventors of the present invention conducted extensive research, and as a result, they came up with the following sealing liquid, method, and sealed connector.

That is, the present invention provides: (1) A sealing solution for treating a copper-based or iron-based metal material plated with nickel as an intermediate layer and then plated with gold or a gold alloy, comprising: (A) paraffin wax 0; ．．
1 to 3 wt% and (B) an organic solvent solution containing one or more compounds selected from two or more of the following groups (a) to (e). A pore sealing solution.

(a) 0.05-3 wt% isostearic acid, oxidized wax, and petrolatum oxide, (b) 0.05-3 wt% alkyl-substituted naphthalene sulfonate, (c) 0.05-3 wt% amine, (d) Metal Soap 0.05-3 wt%, (e) phthalate, phosphite, glycerin heptanoester, and sorbitan ester, 0.01-3 wt%.

(2) One or two chelate-forming cyclic nitrogen compounds
The pore-sealing treatment liquid according to (1) above, further containing 0.05 to 31% of a species or more.

(3) The sealing solution according to (1) or (2) above, further comprising 0.001 to tvt% of one or more amine-based or phenol-based antioxidants.

(4) After plating nickel as an intermediate layer on a copper-based or iron-based metal material and further electroplating gold or a gold alloy thereon, the sealing solution described in (1), (2), or (3) above is applied. A pore sealing method characterized by processing.

(5) After pressing the copper-based or iron-based metal material plated with nickel and gold or gold alloy, the above (1) and (2) are applied.
Or a pore sealing method characterized by treating with the pore sealing solution according to (3).

(6) Made of a plating material in which a copper-based or iron-based metal material is plated with nickel as an intermediate layer, and then gold or gold alloy is plated, and the sealing solution described in (1), (2) or (3) above is used. This connector is characterized by being sealed.

Paraffin wax, which is an essential component of the pore-sealing solution of the present invention, is a saturated hydrocarbon mixture with a molecular weight of about 300 to 500, whose main component is a linear hydrocarbon with an average carbon number of about 20 to 35. In the present invention, paraffin wax has a function as a base oil, that is, it forms a film on the gold-plated surface where many pinholes are present, and through microscopic defects in the gold plating such as pinholes, the paraffin wax acts as a base oil. This prevents moisture, oxygen, and various corrosive media from coming into contact with the nickel base. The most important effect is achieved in stably maintaining the performance of electrical contacts over a long period of time in an environment where corrosion and wear coexist, which is the objective of the present invention.

In other words, lanolin, petrolatum, grease, mineral oil, etc. are known to be used as rust preventives in steel, etc., but these soft base oils are sticky, so dust particles in the atmosphere can adhere to them, causing damage to electrical contacts. When it is repeatedly rubbed, it accelerates the wear of the gold plating, and at the same time, the sealing function deteriorates and corrosion progresses, which significantly shortens the life of the electrical contacts. In the present invention, it has been discovered that paraffin wax does not have these defects and is extremely suitable as a base oil for a sealing liquid for gold-plated contacts.

In the present invention, the selection of this base oil is an important component in improving the above-mentioned corrosion resistance and durability in combination with the effects of other components. Especially unlike rust inhibitors for steel, etc.
In some cases, the base oil is used as a sealing agent for the contact surfaces of electronic components such as connectors that must reliably connect a weak current on the order of microamperes to a mating terminal. Inheritance is extremely important. If the concentration is less than 0.1 wt%, corrosion resistance and durability will decrease, making it impossible to obtain the desired effects. If the amount is more than 3 wt%, the contact resistance increases and the sealing treatment for contacts becomes useless, which is not preferable.

Another essential component of the sealing solution of the present invention is the following (
selected from two or more of the groups a) to (e).

That is, (a) 0.05-3 wt% of isostearic acid, oxidized wax, and petrolatum oxide (b) 0.1-3 wt% of alkyl-substituted naphthalene sulfonate
3wt% (c) Amine (1,05-3w1%) (d) Metal soap 0.05-3vt% (e) Phthalate, phosphite, glycerin heptanoester, and sorbitan ester 0,01-3
wt%, and these are added singly or in a mixture of two or more from two or more groups, and contribute to improving corrosion resistance. The amount of the above components (a) to (d) added is 0.0! +-
It is 3wt%. If it is less than 0.05 wt%, the antirust effect is low, and if it exceeds 3 wt%, an adverse effect on contact resistance is observed.

In addition, the amount of component (e) added is in the range of 0.01 to 3 wt%, and if it is less than 0.01 wt%, the corrosion resistance improvement effect will be reduced.
If it exceeds 3vt%, it is recognized that it has an adverse effect on the contact resistance.

The alkyl-substituted naphthalene sulfonate as the component (b) used in the present invention is represented by the following formula.

(R is an alkyl group having 6 to 12 carbon atoms; M is a salt-forming component;
(n is an integer of 1 to 2, m is an integer that matches the valence of M) Preferred examples of the alkyl-substituted naphthalene sulfonate include, for example, dinonylnaphthalene sulfonate barium salt, dinonylnaphthalene Sulfonate calcium salt, dinonylnaphthalenesulfonate zinc salt, dinonylnaphthalenesulfonate barium basic salt, dinonylnaphthalenesulfonate ethylenediamine salt, dinonylnaphthalenesulfonate sodium salt, and dinonylnaphthalenesulfonic acid Examples include lithium salt, dinonylnaphthalenesulfonic acid lead salt, dinonylnaphthalenesulfonic acid ammonium salt, and dinonylnaphthalenesulfonic acid triethanolamine salt. These are added singly or in a mixture of two or more, and contribute to improving corrosion resistance. The amount added is 0.05 to 3 wt%. 0. (If it is less than 15i%, no effect of improving corrosion resistance can be obtained, and if it exceeds 3wt%, an adverse effect on contact resistance is observed.

The amine of component (C) used in the present invention is preferably an aliphatic amine or a cycloaliphatic amine, and particularly preferred include octadecylamine, dodecylamine, decylamine, octylamine, and cyclohexylamine. I can do it.

Particularly preferred metal soaps as component (d) used in the present invention include, for example, petrolatum oxide metal salts, oxidized wax metal salts, stearate metal salts, laurate metal salts, lysylsinate metal salts, myristic acid. Examples include acid metal salts, oleic acid metal salts, naphthenic acid metal salts, lanolic acid metal salts, etc. The metal salts are not particularly limited, but preferably Ca
, AI, Ba5Pb salt, etc.

Examples of the phthalate ester of component (e) used in the present invention include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2-ethylhexyl phthalate, Diisononyl phthalate, octyldecyl phthalate,
Examples include diisodecyl phthalate.

Examples of the phosphite include triphenyl phosphite, tricresyl phosphite, diphenylnonylphenyl phosphite, trilauryl phosphite,
Examples include dilauryl hydrogen phosphite.

Examples of glycerin monoester include glycerin monooleate.

Examples of the sorbitan ester include sorbitan mono-laurate, sorbitan mono-stearate, sorbitan mono-palmitate, sorbitan mono-oleate, sorbitan sesqui-oleate, and sorbitan tri-oleate.

A chelate-forming cyclic nitrogen compound: an amine-based or phenol-based antioxidant may be added to the pore-sealing solution of the present invention, if necessary. Chelate-forming cyclic nitrogen compounds are compounds that form stable chelates by coordinating with copper, nickel, etc., and in particular, cyclic nitrogen compounds having a benzene ring,
Alternatively, triazine compounds are preferred. To give specific examples, cyclic nitrogen compounds having a benzene ring include, for example, benzotriazole, indazole, benzimidazole, indole (in each of the above formulas, R1 represents hydrogen, alkyl, substituted alkyl, R2 represents an alkali metal, (representing hydrogen, alkyl, substituted alkyl), etc.

Examples of the henctriazole type include benzotriazole (both R1 and R2 are hydrogen), ■-methylbenzotriazole (R+ is hydrogen, R2 is methyl), 1-(N, N
-dioctylaminomethyl)benzotriazole (R+
or hydrogen, R2 is N, N-dioctylaminomethyl), tolyltriazole (R+ is methyl, R2 is hydrogen), sodium tolyltriazole (R+ is methyl, R2 is sodium), and the like.

Examples of indazole series include indazole (R1,
R2 is hydrogen), 2-methylindazole (R+ is hydrogen, R2 is methyl), 2-benzylindazole (R+
is hydrogen, R2 is (:6 I5 CH2), and ■-acetylindazole (R+ is hydrogen, R2 is C0CH5), etc. are preferable.

Examples of benzimidazole systems include benzimidazole (both R1 and R2 are hydrogen), N-acetiibenzimidazole (R+ or hydrogen, R2 or C0CH2), N-benzoylbenzimidazole (R+ or hydrogen, R2 is C0
C6H3) etc. are preferred.

As an indole type, for example, indole (R1, R2
(both are hydrogen), indole-1-carboxylic acid (R+ is hydrogen, R2 is C00H), and -methylindole (R+ is hydrogen, R2 is CH3).

Further, preferable specific examples of triazine compounds include, for example, 6-substituted-1,3,5-triazine-2,4
-dithiol-sodium salt (R is an amino group substituted with an alkyl group, preferably -N(C4I9) 2,
-N(C8Hrr) 2, -N(CI2H29) 2
, -NHO2H16CH-CHCs Hrt, etc.)
, cyanuric acid (2,4,6-trioxy-1,3,5-triazine), H melamine (2,4,6-triamino-1,3,5-triazine), and the like. These are added singly or as a mixture of two or more to improve corrosion resistance and durability together with rosefinx.The total concentration is 0.05 to 3.
It is wt%. If it is less than 0.05 wt%, corrosion resistance and durability will be low, and if it is more than 3 wt%, electrical connectivity will be impaired.

In addition, examples of the above-mentioned amine-based or phenolic antioxidants that may be added to the sealing solution of the present invention as needed include P,P'-dioctyldiphenylamine 4.4'-tetramethyldiaminodiphenyl Meta 4.4゛-methylene-
Bis-(2,6-sheet-t-butylphenol) (CH3) 30 C(CHx) 32.2”
-Methylene-bis-(4-methyl-8-t-butylphenol) CH3CHy 2.2'-methylene-bis-(4-ethyl-et-butylphenol) CH2CH3CH2CH3 2,6-di-t-butyl-p-cresol H CH3 Butylated hydroxyanisole 0CHz 0CR3 2,6-di-t-butyl-4-ethylpheno-H2CH
3 etc. can be mentioned.

One or more of these can be added in an amount of 0.001 to 1 νt%.

By adding these components, durability can be further improved. That is, it has the effect of stabilizing the function of the sealing film over a long period of time and suppressing deterioration of the film in a high-temperature environment. If it is less than 0.001 vt %, the effect cannot be obtained, and if it exceeds 1 νt 96, a decrease in contact resistance is observed.

The pore-sealing liquid may have the above-mentioned components, or the solvent may be appropriately selected from known organic solvents without any particular limitations. Examples include petroleum-based solvents such as toluene and quinoa, halogen-based solvents such as trichloroethylene and trichloroethane, and fluorocarbon-based solvents.

As a treatment method, any method can be used, such as immersing the plated product in a pore sealing solution, or spraying or applying the pore sealing solution. However, in the present invention,
Regardless of whether the shape of the plated product is a plate, strip, or pressed part,
It has been found that performing the treatment immediately after plating, that is, in a continuous line, is highly effective in enhancing various functions of the sealing treatment.

Furthermore, it is also effective to seal the plated product using the sealing solution of the present invention after press working. Even with metal materials that have been sealed after plating, many of the functions of the sealing process are lost in the process of cleaning the press pores that have adhered during subsequent press working, so re-sealing is effective. .

In the subsequent connector processing steps as well, if there is a cleaning step for the plated product until the final assembly of the electronic device, the hole sealing function will be similarly lost, so it is effective to perform hole sealing according to the present invention as appropriate. Furthermore, even when it is incorporated into an electronic device as a connector and used in actual use, if the contact performance deteriorates with use, it can be treated with the present sealing treatment liquid as appropriate. Therefore, the present invention also includes connectors treated with the sealing solution of the present invention.

In addition, in the present invention, the metal material serving as the plating base material is:
Copper, various copper alloys such as brass, phosphor bronze, and titanium copper, iron, stainless steel, high nickel alloys, etc. can be selected as appropriate according to the required performance of the connector, and there are no equal restrictions. For the nickel plating as the intermediate layer, known methods such as electroplating from a Watt bath, sulfamic acid bath, etc., electroless plating, etc. can be applied, and the plating method is not limited. In addition to applying nickel plating directly to the metal base material, it is also possible to have another metal layer in between. Gold plating includes pure gold plating from various alkaline baths and acidic baths, as well as gold alloy plating containing alloy components such as cobalt.

[Example] The present invention will be explained in more detail with reference to Examples below.

Male and female continuous terminals were each press-molded using cold-rolled spring material of phosphor bronze (C5210) with a thickness of 0.2 aa+. These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, 1 μm nickel plating is applied in Watt bath, and then 0.2 μm gold plating is applied in acid plating bath.
The contacts are partially plated with a thickness of μ■. In addition, in the continuous plating line, a sealing process was provided after gold plating, and in this process, the continuous terminal was passed through various sealing solutions using trichloroethane as a solvent to perform the sealing process.

After the male and female terminals thus surface-treated were cut from a portion of the carrier and the lead wires were crimped, they were fitted together and subjected to an evaluation test.

The contact resistance was measured at a direct current of 10 aiA and an open circuit voltage of 50 mmV. The corrosion test was conducted under the following conditions.

Gas composition: H2S 3±1ppa+502 10±
3ppm Temperature = 40±2℃ Humidity Near 5±5% RH Time: 96 hours The combined test was conducted using an automatic repeating insertion/extraction device for male and female terminals.
After conducting a wear test in which insertion and removal were repeated 0 times, the test piece was subjected to the corrosion test described above, and the contact resistance was further measured. The results are shown in Table 1.

Table 1 Table 1 continued (1) Table 1 continued (2) Table 1 continued (3) Note 1) However, the abbreviations of the sealing liquids in the table are as follows.

A Paraffin wax B-1 Isostearic acid - Wax 2 oxide - Petrolatum 3 oxide - 4 Barium dinonylnaphthalene sulfonate salt - 5 Carunium dinonylnaphthalene sulfonate salt - 6 Zinc salt of dinonylnaphthalene sulfonate - 7 Dinonyl Naphthalenesulfonate barium basic salt -8 Dinonylnaphthalenesulfonate ethylenediamine salt -9 Dinonylnaphthalenesulfonate sodium salt B-10 Tunonylnaphthalenesulfonate lithium salt -11 Octade/Lamine -12 Dodecylamine -13 Decylamine - 14 Octylamine - 15 Cyclohexylamine - 18 Petrolatum oxide Ca salt - 17 Oxidized wax Ca salt - 18 Stearic acid Ca salt - 19 Lauric acid A1 salt - 20 Phosphoruric acid AI salt - 21 Myristic acid Ca salt - 22 Oleic acid Ba salt -23 Naphthenic acid Ba salt -24 Lanolic acid A1 salt -257 Tumethyl talate = 26 7 Diethyl talate = 27 Dibutyl phthalate - 287 Dihebutyl talate - 297 Di-n-octyl talate - 30 No-2-ethylhexyl phthalate - 317 Diisononyl tallate - 327 Octyldenyl tallate - 337 Diisodenyl tallate - 34 Triphenyl phosphite - 35 Tricresyl phosphite - 36 Diphenylnonylphenyl phosphite - 37 Trilauryl phosphite 38 Dilauryl hydrogen phosphite - 39
Glycerin monooleate B-40 Sorbitan mono-laurate-41 Sorbitan mono-stearate-42 Sorbitan mono-palmitate-43 Sorbitan mono-oleate-44 Sorbitan sesqui φ oleate-45 Sorbitan tri-oleate C-1 Benzotriazole-2 Indazole -3 Benzimidazole-4 Indole-51-Methylbenzotriazole-6 Tolyltriazole-7 Sonolamtolyltriazole = 8 Melamine D-I P, P'-dioctylnophenylamine-2
4,4°-tetramethyldiaminodiphenylmethane-3
4,4'-methylene-bis-(2,6-not-t-butylphenol)-42,2'-methylene-bis-(4-methyl-6-t-butylphenol) -52,2'-methylene-bis- (4-ethyl-a-t
-butylphenol) -62,6-not-t-butyl-p-cresol-7-butylated hydroquinanisole-82,6-di-t-butyl-4-ethylphenol Note 2) The test criteria are as follows: .

■Initial contact resistance, contact resistance after combined test (average value of n-5) ○ = 25 soda wet Ω or less △, 25 to 50 ssΩ Traces of products are present △ Corrosion products are scattered X, corrosion points are observed on the entire surface [Effects of the invention] As described above, the nickel-based, gold-plated contacts sealed according to the present invention are It has low contact resistance, exhibits excellent corrosion resistance even in harsh corrosive environments, and has the advantage that contact resistance does not increase even with thermal history and contact performance is stable.

Patent Applicant: Japan Mining Co., Ltd. Patent Applicant: Kyoseki Product Technology Institute Co., Ltd. Agent Patent Attorney: Hidetake Komatsu

Claims (6)

[Claims] (1) A sealing solution for treating a copper-based or iron-based metal material plated with nickel as an intermediate layer and then plated with gold or gold alloy, comprising: (A) paraffin wax 0.
1 to 3 wt% and (B) an organic solvent solution containing one or more compounds selected from two or more of the following groups (a) to (e). A pore sealing solution. (a) 0.05-3 wt% of isostearic acid, oxidized wax, and petrolatum oxide; (b) 0.05 alkyl-substituted naphthalene sulfonate;
~3wt%, (c) amine 0.05~3wt%, (d) metal soap 0.05~3wt%, (e) phthalate ester, phosphite ester, glycerin monoester, and sorbitan ester 0.01~ 3
wt%. (2) One or two chelate-forming cyclic nitrogen compounds
The pore-sealing treatment liquid according to claim 1, further comprising 0.05 to 3 wt% of at least one species. (3) The pore-sealing treatment liquid according to claim (1) or (2), further comprising 0.001 to 1 wt % of one or more amine-based or phenol-based antioxidants. (4) After plating nickel as an intermediate layer on a copper-based or iron-based metal material and further electroplating gold or a gold alloy thereon, the sealing treatment according to claim (1), (2) or (3) is performed. A pore sealing method characterized by treatment with a liquid. (5) After pressing a copper-based or iron-based metal material plated with nickel and gold or a gold alloy, claims (1) and (2)
) or (3). (6) The sealing treatment liquid according to claim (1), (2) or (3), which is made of a plating material in which a copper-based or iron-based metal material is plated with nickel as an intermediate layer and then plated with gold or a gold alloy. A connector characterized in that the pores are sealed with.