JPH04160193A - Sealing treating solution and method therefor - Google Patents

Abstract

PURPOSE:To seal pinholes in an Au series coating layer and to manufacture a connector having excellent corrosion resistance and small contact resistance by treating a connector having the electroplating film of Au or an Au alloy on an Ni plating film by a sealing treating soln. having a specified compsn. CONSTITUTION:As an intermediate layer, Ni plating is applied to the surface of a connector base metal by a Cu series or ferrous metal, on which the electroplating of Au or an Au alloy is applied. Then, press working is executed, and after that, many micropinholes in an Au series plating film are subjected to sealing treatment. As a treating soln., the one contg., as essential components, by weight, 0.1 to 3% paraffin wax and 0.05 to 3% of one or more kinds among metallic soap, and, if required, in which 0.05 to 3% of one or more kinds among chelate formable ring N compounds or, furthermore, 0.001 to 1% of one or more kinds among aminic or phenolic oxidation preventing agents are dissolved in an organic solvent such as toluene, xylene or the like is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sealing solution for gold-plated electrical contacts, a sealing method, and a sealed connector. Sealing liquids and sealing treatments that provide stable, long-term lubrication, rust prevention, and electrical connectivity for electrical contacts, especially under harsh usage conditions where wear and corrosion progress simultaneously due to repeated insertion/extraction and vibration. The present invention relates to a 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 steel, 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 method to solve this problem is pore 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 to lubricate gold-plated contacts even before the use of livestock housing. Generally, the lubricant used for the intended purpose was used as is.

The properties required for sealed gold plating include: ■ Good lubricity; ■ Excellent corrosion resistance; ■ Low and stable contact resistance; ■ Good solderability. and ■ Those characteristics persist over a long period of 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 though the sealing treatment initially had excellent lubricity, the sealing film becomes contaminated with dust and other particles from the atmosphere during repeated insertion and removal. There was a problem of adhesion and accelerated wear.

Furthermore, with the rapid progress in the use of electronic devices 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 from the car body, as well as extremely severe corrosion caused by various corrosive gases in the atmosphere in industrial areas, sea salt particles in coastal areas, and snow melting agents in cold regions. exposed to the environment.

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; ．．
A pore-sealing treatment liquid comprising an organic solvent solution containing as essential components 1 to 3 wt% and 0.05 to 3 wt% of one or more metal soaps (B).

(2) The sealing solution according to (1) above, further comprising 0.05 to 3 wt% of one or more chelate-forming cyclic nitrogen compounds.

(3) The sealing solution as described in (1) or (2) above, further containing 0.001-1 wt% of one or more of amine or phenolic antioxidants.

(4) Plating a copper-based or iron-based metal material with nickel as an intermediate layer, further electroplating gold or a gold alloy thereon, and then treating with the sealing solution described in (1) or (2) above. A pore sealing method characterized by:

(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 (3) A pore-sealing method characterized by treating with the pore-sealing solution described in (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 and whose main component is a linear hydrocarbon with an average carbon number of about 20 to 35.

In the present invention, paraffin wax functions as a base oil. In other words, it forms a film on the gold plating surface that has many pinholes, and through microscopic defects in the gold plating such as pinholes, moisture, oxygen, and various corrosive agents in the atmosphere can interact with the underlying nickel. Preventing contact.

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. physical connectivity will be extremely important. If the concentration is less than 0.1 vt%, corrosion resistance and durability will be reduced, making it impossible to obtain the desired effect. If it is more than 3 wt%, the contact resistance increases and it becomes useless as a sealing treatment for contacts, which is not preferable.

Another essential component of the pore sealing solution of the present invention is metal soap. Particularly preferred metal soaps in the present invention include, for example, petrolatum oxide metal salts, oxidized wax metal salts, stearate metal salts, laurate metal salts,
Examples include metal salts of lysylsinate, metal salts of myristate, metal salts of oleate, metal salts of naphthenate, and metal salts of lanophosphate.Although there are no particular restrictions on the metal salt, Ca is preferred.

These include AI, Ba, and Pb salts. These are used alone or in a mixture of two in a total amount of 0.05 to 3 wt%.

If it is less than 0.05 wt%, the effect of improving corrosion resistance cannot be obtained, and if it exceeds 3 wt%, an adverse effect on contact resistance is observed.

Furthermore, one or more of a chelate-forming cyclic nitrogen compound and an amine-based or phenol-based antioxidant can be added to the pore-sealing solution of the present invention, if necessary. The chelate-forming cyclic nitrogen compound is a compound that forms a stable chelate by coordinating with copper, nickel, etc., and is particularly preferably a cyclic nitrogen compound having a benzene ring or a triazine-based compound. To give specific examples, cyclic nitride compounds having a benzene ring include, for example, benzotriazole-based indazole-based $ benzimidazole-based indole-based (in each of the above formulas, R1 represents hydrogen, alkyl, or substituted alkyl, and R2 represents an alkali metal , hydrogen, alkyl, substituted alkyl).

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

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 Cb R5CH2), l-acetylindazole (R+ is hydrogen, R2 is C0CH5), and the like are preferred.

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

Examples of indole series include indole (R1, R2
(both are hydrogen), indole-I-carboxylic acid (R+ is hydrogen, R2 is C00H), 1-methylindole (R+ is hydrogen, R2 is CH3), and the like are preferred.

In addition, preferred specific examples of triazine compounds include:
For example, 6-substituted-1,3,5-triazine-2,4-
Dithiol-sodium salt (R represents an amino group substituted with an alkyl group, such as -N(C4H9)2,
-N(Os HI?) 2, -N(CI2H25) 2
, -NHCs HiCH-CHCs HI7, etc. are preferred), cyanuric acid (2,4,6-trioxy-1,3,5-triazine), H melamine (2,4,6-triamino-1,3,5- triazine), etc. These are added singly or as a mixture of two or more, and together with paraffin wax, they provide corrosion resistance,
Improve durability. The total concentration is 0.05~3ν
t%. 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°-tetramethyldiaminodiphenylmeth 4.4'-methylene-
Bis-(2,6-di-t-butylphenol) (CH3) 3 CC(CH3) 3 2,2'-methylene-bis-(4-methyl-et-butylphenol) CH3CH3 2,2"-methylene-bis -(4-ethyl-1f-t-
butylphenol) CH2C)13 CI2 C)13 2,6-di-t-butyl-p-cresol H CH cobutylated hydroxyanisole 0CR30CH3 2,6-di-t-butyl-4-ethylpheno-CIlz
CIz etc. can be mentioned.

These include one or more types in total amount o, oot~lvt
% can be added.

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 the content is less than 0.001 wt%, this effect cannot be obtained, and if it exceeds 1 wt%, a decrease in contact resistance is observed.

Although the pore-sealing liquid has the above-mentioned components, the solvent is not particularly limited and can be appropriately selected from known organic solvents. Examples include petroleum-based solvents such as toluene and xylene, 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 the shape of the plated product, whether it 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 with the sealing solution of the present invention after press working. Even for metal materials that have been sealed after plating, much of the sealing function is lost in the process of cleaning press oil adhering during subsequent press working, so re-sealing becomes effective.

In the subsequent processing steps of the connector 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 the hole sealing process according to the present invention as appropriate. Furthermore, even when the connector is incorporated into an electronic device 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 code] 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 phosphor bronze (C5210) for springs with a thickness of 0.2 mm. These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, 1μ nickel plating is applied in Watt bath, and then 0.2 μμ gold is applied in acid plating bath.
The contacts are partially plated to a thickness of -. 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 mmA and an open circuit voltage of 50 mmV. The corrosion test was conducted under the following conditions.

Gas composition: H2S 3±lppm SO210±3ppm Temperature: 40±2℃ Humidity Near 5±5%RH Time: 96 hours In the combined test, male and female terminals were inserted 10 times using an automatic repeating insertion/extraction device.
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 A Paraffin wax B-1 Petrolatum oxide Ca salt - 2 Oxidized wax Ca salt - 3 Stearic acid Ca salt - 4 Lauric acid A1 salt - 5 Phosphorus acid AI salt - 6 Myristic acid Ca salt - 7 Oleic acid Ba salt - 8 Naphthenic acid Ba salt - 9 Lanolic acid A1 salt C-1 Benzotriazole-2 Indazole-3 Benzimidazole-4 Indole-51-methylbenzotriazole = 6 Tolyltriazole-7 Sodium Tolyltriazole-8 Melamine D-IP, P-nooctylumphenylamine-24
,4°-tetramethylnoaminodiphenylmethane-34
,4-methylene-bis-(2,6-di-t-butylphenol)-42,2'-methylene-bis-(4-methyl-8-t-butylphenol)-52,2°-methylene-bis-(4 -ethyl-8-t
-butylphenol) -62,6-di-t-butyl-p-cresol-7-butylated hydroxyanisole-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) 0: 251 ■Ω or less Δ, 25 to 50 ■Ω X: 50 m-Ω or more ■Appearance after corrosion test ◎: No corrosion products observed No ○: Traces of corrosion products Δ Corrosion products dotted [Effects of the invention] As described above, the contact with the nickel base and gold plating sealed by the present invention has a low contact resistance immediately after the treatment. It has the advantage that it exhibits excellent corrosion resistance even in harsh corrosive environments, and that contact resistance does not increase due to 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.
A pore-sealing treatment liquid comprising an organic solvent solution containing as essential components 1 to 3 wt% and 0.05 to 3 wt% of one or more metal soaps (B). (2) The sealing solution according to claim (1), further comprising 0.05 to 3 wt% of one or more chelate-forming cyclic nitrogen compounds. (3) The sealing solution according to claim (1) or (2), further comprising 0.001 to 1 wt% of one or more amine-based or phenol-based antioxidants. (4) Plating nickel as an intermediate layer on a copper-based or iron-based metal material, and further electroplating gold or a gold alloy thereon, and then treating with the sealing solution according to claim (1) or (2). A pore sealing method characterized by: (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) A method for sealing, characterized by treating with the sealing solution described in (3). (6) The sealing solution 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.