JPH04193994A - Sealing solution and method - Google Patents

Abstract

PURPOSE:To improve lubricity and corrosion resistance and to reduce and stabilize contact resistance by treating a metallic material plated with Ni, Pd and Au with an org. solvent soln. contg. paraffin wax and metallic soap as the essential components. CONSTITUTION:An org. solvent soln. contg. 0.1-3wt.% paraffin wax and 0.05-3wt.% metallic soap as the essential components is prepared, or a sealing soln. contg. 0.05-3wt.% of a chelating cyclic nitrogen compd. in addition to the soln. is prepared. A copper or iron-based metallic material having a Pd (alloy) plating on an Ni plating substrate layer and further an Au (alloy) plating thereon is treated with the sealing soln. to seal pinholes.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sealing solution for gold-plated electrical contacts, a sealing method, and a sealed connector.

Lubricating electrical contacts, especially under harsh operating conditions where repeated insertion and removal and vibration cause wear and corrosion at the same time.
The present invention relates to a sealing solution, a sealing method, and a sealed connector that have long-term, stable and excellent rust prevention and electrical connectivity.

[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. Gold is generally used after base plating and then gold plating is applied on top of it.6 Gold has extremely high corrosion resistance among precious metals, and because it does not form oxides or other films on the surface, it has excellent electrical connectivity and is suitable for contact points. It is widely used as a metal.

However, since gold is expensive, various metallurgical shapes have been used 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. .

Therefore, after plating a nickel base, palladium or palladium alloy is plated as an intermediate plating, and then gold plating is used5.However, even this three-layer plating does not provide sufficient corrosion resistance, and this problem can be solved. One method to solve this problem is pore sealing6. In other words, treating the gold-plated surface with various inorganic or organic chemicals,
This is intended to improve corrosion resistance by closing pinholes, but it is necessary to apply a sealing solution and sealant to a material that is plated with nickel as the base layer, palladium or palladium alloy as the intermediate layer, and then gold plated on top of that. There is no known hole treatment method.

[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 are mainly selected from compounds known as rust preventive agents for iron-based metal materials and copper-based metal materials.

Alternatively, it was common to use the lubricant that had been used for the purpose of lubricating gold-plated contacts even before the ordinance was introduced. The properties required for sealed gold plating are: ``D 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 is becoming increasingly sophisticated, such as the electrical contacts (or connectors) of IC cards, which must guarantee electrical connectivity even after being inserted and removed 10,000 times. .

However, after being inserted and removed 10,000 times over a long period of time, even though the sealing treatment initially had excellent lubricity, dust and other particles in the atmosphere formed on the sealing film during re-insertion and removal. There was a problem in that it adhered and accelerated wear.

In addition, 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.

The object of the present invention is to provide a modified sealing liquid that can meet such requirements and a sealing method using the same, and also to provide a connector treated with the same. This is the purpose.

[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 treatment solution for treating a copper-based or iron-based metal material that is plated with nickel as a base layer, palladium or a palladium alloy as an intermediate layer, and then plated with gold or a gold alloy. (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 treatment according to (1) or (2) above, which contains one or more amine-based or phenol-based acid inhibitors at 0.001 to 42 Lvt%. liquid.

(4) After plating a copper-based or iron-based metal material with nickel as a base layer, palladium or palladium alloy as an intermediate layer, and then electroplating gold or gold alloy thereon, described in (1) or (2) above. A pore sealing treatment method characterized by treating with a pore sealing treatment liquid.

(5) After plating nickel as the base layer and plating palladium or palladium alloy as the intermediate layer, press the copper-based or iron-based metal material plated with gold or gold alloy, and then press the above (1), (2) or (3). ) A method for sealing, characterized by treating with the sealing solution described in ).

(6) A plating material in which a copper-based or iron-based metal material is plated with nickel as a base layer, palladium or a palladium alloy as an intermediate layer, and then plated with gold or a gold alloy, as described in 0), (2), or (3) above. ) A connector characterized in that the pores are sealed using the pore sealing solution described in .

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 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. This is the objective of the present invention, which is the most important effect in maintaining stable performance of electrical contacts over a long period of time in an environment where corrosion and wear coexist. That is,
In steel, etc., lanolin, petrolatum, grease, mineral oil, etc. are known for their use as rust inhibitors.

Because such soft base oils are sticky, dust particles in the atmosphere adhere to them, and when electrical contacts are repeatedly rubbed,
It accelerates the wear of the gold plating, and at the same time reduces the sealing function and progresses corrosion, which significantly shortens the life of electrical contacts5.
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 presently plated contacts.

In the present invention, the selection of this base oil is an important component in synergistically improving the above-mentioned corrosion resistance and durability in conjunction 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 wt%, corrosion resistance and durability will decrease, making it impossible to obtain the desired effects. On the other hand, if it is larger than 3vt%, the contact resistance increases and the sealing treatment for contacts becomes useless, which is not preferable.

Another essential component of the pore sealing solution of the present invention is gold 1 soap. Particularly preferred metal soaps in the present invention include, for example, petrolatum oxide metal salts, oxidized wax gold monosalts, stearic acid metal salts, lauric acid metal salts, lysylsic acid gold salts, myristic acid metal salts, oleic acid metal salts, and naphthenic acid metal salts. Examples include acid metal salts, lanophosphate metal salts, and the like.Although there are no particular restrictions on the metal salts, Ca, Al, Ba, and Pb salts are preferable.

These are 1 type or a mixture of 2 types, and the total amount is 0.05~
It is used at 3 wt%. If it is less than 0.03 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 types of chelate-forming cyclic nitrogen compounds; amine-based or phenol-based antioxidants can be added to the pore-sealing treatment liquid 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 a specific example, as a cyclic nitrogen compound having a benzene ring, for example.

Examples include benzotriazole-based μ indazole-based [benzimidazole-based indole-based (in each of the above formulas, R□ represents hydrogen, alkyl, or substituted alkyl, and R2 represents an alkali metal, hydrogen, alkyl, or substituted alkyl), etc. can.

Examples of hensitriazoles include benzotriazole (both R1 and R2 are hydrogen) and 1-methylhensitriazole (R is hydrogen and R2 is methyl).

1-(\,N-dioctylaminemethyl)benzotriazole (R is hydrogen, R2 is N, N-dioctylaminomethyl), tolyltriazole (R is methyl, R2 is hydrogen), sodium tolyltriazole (R is hydrogen), tolyltriazole (R is methyl, R2 is hydrogen), is methyl,
R2 is sodium) etc. are preferred.

Examples of indazole series include indazole (R,
R2 is hydrogen), 2-methylindazole (R is hydrogen, R2 is methyl), 2-benzylindazole (R is hydrogen, R2 is C, H, CH,), 1-acetylindazole (R1 is hydrogen, R2 is is C○CH, ) etc. are preferable.

Examples of benzimidazole systems include benzimidazole (both R and R2 are hydrogen), X-acetiibenzimidazole (R is hydrogen and R2 is COCH2), and N-benzoylbenzimidazole (R is hydrogen and R2 is CO).
CGH, ) etc. are preferred.

As an indole type, for example, indole (R, R2
(both are hydrogen), indole-1-carboxylic acid (RL is hydrogen, R2 is C○○H), 1-methylindole (R is hydrogen, R2 is CH3), and the like are preferred.

Further, preferable 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(CJi)z, -
3 (cmHot) 2, -N (C engineering 2H25) 2.4HC
Preferred are sH, CH==CHC, HF, etc. )
, cyanuric acid (2,4,6-trioxy-1,3,5-
triazine).

Examples include melamine (2,4,6-)-riamino-1,3,5-triazine), and H. 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 0.05~3w
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, the above-mentioned amine-based or phenol inhibitors that may be added to the sealing solution of the present invention as needed include:
for example.

P, P'-cy'octyldiphenylamine 4.4'-
Tetramethyldiaminodiphenyl meta 4.4'-methylene-bis-(2,6-di-t-butylphenol) 2.2'-methylene-bis-(4-methyl-6-di-butylphenol) 0) 1 Of( CH , CH.

2.2'-Methylene-bis-(4-ethyl-6-butylphenol) OHOH CH2CH1CH2CH.

2.6-di-t-butyl-p-cresol H CH.

Butylated hydroxyanisole 0) 1 0H2,6-di-monobutyl-4-ethylphenol H CH2CH.

etc. can be mentioned.

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

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 0.0O1i%, the effect cannot be obtained,
If it exceeds 1 wt%, a phenomenon of 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, fluorocarbon-based solvents, and 8-solvents.

As a treatment method, a circular method such as immersing the plated product in a pore-sealing solution, spraying or coating the pore-sealing solution can be used. 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 with metal materials that have been sealed after plating, most of the sealing function is lost during the subsequent process of cleaning press oil adhering during press working. Therefore, 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. Even when the bulge is incorporated into electronic equipment as a connector, if the contact performance deteriorates with use, it can be treated with the present pore-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 restrictions on the answer. For the nickel plating as the base layer or the palladium or palladium alloy plating as the intermediate layer, known methods such as electroplating, electroless plating, or dry plating such as CVD or PVD can be applied, and the plating method is not limited.

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 a cold-rolled material of phosphor bronze (C5210) for springs with a thickness of 0.2 nn. These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, 1 μm nickel plating in Watt bath, 0°3 μm palladium-nickel alloy plating with neutral palladium-nickel alloy plating solution, and 0.1 μm gold plating in acidic plating bath. The contacts were 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.

The thus surface-treated pheasant and female terminals were cut from a portion of the carrier, and after crimping a leet wire, 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±ippm SOz 1
0±39ρm Temperature = 40±2℃ Humidity = 75±5%RH Time = 96 hours For the combined test, male and female terminals were inserted and removed 100 times using an automatic repeating insertion/extraction device.
After performing a wear test in which the wires were repeatedly inserted and removed several times, they were subjected to the corrosion test described above, and the contact resistance was further measured.

The results are shown in Table 1.

Table 1 Note 1) However, the abbreviations for the sealing liquids in Table 1 are as follows.

A Paraffin wax B-19ated petrolatum Ca salt-2 Oxidized wax Ca salt-3 Stearic acid Ca salt-4 Lauric acid A1 salt-5 Lysylcinic acid A1 salt-6 Myristic acid Ca salt-7 Oleic acid Ba salt-8 Naphthenic acid Ba salt-9 Lanolic acid A1 salt C-1 Benzotriazole C-2 Indazole C-3 Benzimidazole C-4 Indole C-51-Methylbenzotriazole C-6 Tolyltriazole C-7 Sodium Tolyltriazole C-8 Melamine D -I P, P' -dioctyldiphenylamine-
24,4'-tetramethyldiaminodiphenylmethane-34,4'-methylene-bis-(2,6-di-butylphenol) -42,2'-methylene-bis-(4-methyl-6-
t-butylphenol) -52,2'-methylene-bis-(4-ethyl-6-
-62,6-di-butyl-p-cresol = 7 Butylated hydroxyanisole-82,6-di-butyl-4-ethylphenol Note 2) The test criteria are as follows: 3rd stage Initial contact resistance, contact resistance after heating test (average value of n=5) 0: 2
5rrtnΩ or less△: 25 to 50nmΩ As mentioned above, after the sealing treatment of the present invention is performed, the contact resistance of the gold-plated contacts after nickel plating as the base layer and palladium or palladium alloy plating as the intermediate blade is severe. It exhibits excellent corrosion resistance even in a corrosive environment, and has the advantage that contact resistance does not increase even with thermal history and contact performance is stable.

Claims (6)

[Claims] (1) A sealing solution for treating a copper-based or iron-based metal material plated with nickel as a base layer and palladium or palladium alloy 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) After plating a copper-based or iron-based metal material with nickel as a base layer, palladium or palladium alloy as an intermediate layer, and then electroplating gold or a gold alloy thereon, claim (1) or (2) A pore-sealing method comprising treating with the pore-sealing solution described above. (5) After plating nickel as a base layer and plating palladium or palladium alloy as an intermediate layer, after pressing a copper-based or iron-based metal material plated with gold or gold alloy, claim (1), (2) or ( 3) A pore-sealing method characterized by treating with the pore-sealing solution described above. (6) It is made of a plated material in which a copper-based or iron-based metal material is plated with nickel as a base layer, palladium or a palladium alloy as an intermediate layer, and then plated with gold or a gold alloy, and claims (1), (2) or (3) A connector characterized in that it has been sealed with the sealing solution described above.