JPH04202697A - Sealing solution and sealing method - Google Patents

Abstract

PURPOSE:To produce a connector with an electrical contact having superior lubricity, corrosion preventiveness and electrical connectivity by successively plating a Cu-based metallic material with Pd and Au and sealing the plated material with a soln. contg. a specified % each of paraffin wax and a metallic soap in an org. solvent. CONSTITUTION:A Cu-or Fe-based metallic material is plated with Pd or Pd alloy to form a middle layer and it is further electroplated with Au or Au alloy. The plated material is then sealed with sealing a soln. This soln. contains 0.1-3wt.% paraffin wax and 0.05-3wt.% one or more kinds of metallic soaps such as Ca and Al salts of oxidized petrolatum and oxidized wax as essential components in an org. solvent such as toluene. The paraffin wax is a satd. hydrocarbon mixture having about 300-500mol.wt. based on straight chain hydrocarbons having about 20-35 average number of C atoms. A connector with a contact having contact resistance not increased by its heat history and stable contact performance is obtd.

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.

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 steel alloys such as phosphor bronze and beryllium copper as the base material, 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 ministerial measures have been taken to reduce the manufacturing cost of connectors. A typical method is to reduce the thickness of the gold plating, but as the thickness of the gold plating increases, the number of pinholes in the film increases exponentially.

The problem is that corrosion resistance is significantly reduced.

Therefore, a material in which the intermediate layer is plated with palladium or a palladium alloy and then gold plated is used. However, even this plating does not provide sufficient corrosion resistance. One method to solve this problem is pore sealing. In other words, the gold-plated surface is treated with various inorganic or organic chemicals to close pinholes and improve corrosion resistance, but palladium or palladium alloy is plated as an intermediate layer, and then There are no known sealing liquids or sealing methods for gold-plated materials.

[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 that were 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 ministerial ordinance was established. It was common to use the same lubricant that was used as a lubricant. 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 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, 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 RIUA] In view of this situation, the present inventors conducted intensive research and as a result, came to invent the following sealing liquid, method, and sealing connector.

That is, the present invention provides: (1) a sealing solution for treating a material that has been plated with gold or gold alloy after plating palladium or palladium alloy as an intermediate layer on a copper-based or iron-based metal material, comprising (A)
A pore-sealing treatment liquid comprising an organic solvent solution containing as essential components 0.1 to 311 t% of paraffin wax and 0.05 to 3 t% of one or more metal soaps (B).

(2) 6 (3) Amine-based or phenol-based pore-sealing liquid according to (1) above, further containing 0.05 to 3 iit% of one or more chelate-forming cyclic nitrogen compounds. One or more antioxidants are added to 0.
The sealing treatment liquid according to (1) or (2) above, further containing 001 to 1 t%.

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

(5) After plating palladium or palladium alloy as an 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 pore sealing treatment method characterized by treating with the pore sealing treatment liquid described in .

(6) It is made of a plating material in which a copper-based or iron-based metal material is plated with palladium or a palladium alloy as an intermediate layer, and then gold or a gold alloy is plated, and
3) A connector characterized in that it has been sealed with the sealing solution described above.

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 enter the intermediate layer. Prevents contact with certain palladium or palladium alloys and metal materials. 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,
At the same time, the sealing function deteriorates and corrosion progresses, significantly shortening 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 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. And its concentration is less than 0.1 t%.

Corrosion resistance and durability decrease, making it impossible to obtain the desired effect. On the other hand, if it 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 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, and the metal salts are not particularly limited, but preferably Ca, These include AI, Ba, and Pb salts. These are one type or a mixture of two types and the total amount is 0.0
It is used at 5 to 3 vt%. If the content is 0.05 wt% without vortex, no improvement in corrosion resistance can 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 specific examples, cyclic nitrogen compounds having a benzene ring include, for example, benzotriazole-based ■ indazole-based benzimidazole-based N indole-based (in each of the above formulas, R1 represents hydrogen, alkyl, or substituted alkyl, and R2 represents (representing an alkali metal, hydrogen, alkyl, substituted alkyl), etc.

Examples of benzotriazole systems include benzotriazole (R, R2 are both hydrogen), ■-methylbenzotriazole (R is hydrogen, R2 is methyl), 1-(N, N
-dioctylaminomethyl)benzotriazole (Rt
is hydrogen, R2 is 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 CGH, CH2), l-acetylindazole (R is hydrogen, R2 is COCH,), etc. are preferred.

Examples of benzimidazole systems include benzimidazole (both R and R2 are hydrogen), N-acetibenzimidazole (R1 is hydrogen, R2 is C0CH2) + N-
Benzoylbenzimidazole (R1 is hydrogen, R2 is c
oc, Hs), etc. are preferred.

As an indole type, for example, indole (R1, R2
(both are hydrogen), indole-1-carboxylic acid (R is hydrogen, R2 is C○○H), l-methylindole (R1 is hydrogen, R2 is CH), 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, for example -N(C4)19)2, -N(C,HF)2,
-N(C□2H1S)2, -Nl(C,)l, CH
= CHC, H-1, etc. are preferred), cyanuric acid (2,
4,6-)-lioxy-1,3,5-triazine), melamine (2,4,6-triamino-1,3,5-triazine).

etc. can be mentioned. 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 0.05wt%, corrosion resistance and durability will be low, and if it is more than 3vt%, electrical connectivity will be impaired.

In addition, examples of the above-mentioned amine-based or phenolic antioxidants which 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) (CI(,), CG(CH3).

2.2'-methylene-bis-(4-methyl-6-t-butylphenol) CH,CH.

2.2'-Methylene-bis-(4-ethyl-6-t-butylphenol) OHOH CH2CH, CH2CH.

2.6-di-t-butyl-p-cresol H CH□ Butylated hydroxyanisole OH0H OCR, OCH.

2.6-di-butyl-4-ethylphenol H C) 12CH.

etc. can be mentioned.

These include one or more types in a total amount of 0.001 to 1w.
t% 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 it 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,
The shape of the plated product is a plate or strip.

Regardless of whether it is a pressed part, we have found that treating it immediately after plating, that is, in a continuous line, is highly effective in improving various functions of the sealing process.

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 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 if 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 pore sealing treatment liquid as appropriate. Therefore, the present invention also includes connectors treated with the sealing solution of the present invention.

1. In the present invention, the metal material serving as the plating base material includes copper and various copper alloys such as brass, phosphor bronze, titanium copper, etc.
Iron, stainless steel, high nickel alloy, etc. can be selected as appropriate according to the required performance of the connector, and there is no restriction in any way. As the palladium or palladium alloy plating for the intermediate layer, known methods such as electroplating, electroless plating, or dry plating such as CVD and 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 cold-rolled spring material of phosphor bronze (C5210) with a thickness of 0.2 NO. These were electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, neutral type palladium
0.3μm palladium by nickel alloy plating bath
After nickel alloy plating, 0.1% gold is applied in an acidic plating bath.
The contacts were partially plated to a thickness of μm. 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 nn+A and an open circuit voltage of 50 a+V. The corrosion test was conducted under the following conditions.

Gas composition: H2S 3±lppm5o2 10±
3pptn Temperature: 40±2℃ Humidity: 75±5%RH Time: 96 hours In the combined test, male and female terminals were inserted and removed using an automatic edge-turning device for 10 minutes.
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 Note 1) However, the abbreviations for the sealing liquids in the table are as follows.

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 Lysylcinic acid A1 salt-6 Myristic acid Ca salt-7 Oleic acid Ba salt-8 Naphthenic acid Ba salt-9 Lanolic acid Al 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-t-butyl-p-cresol-7-butylated hydroxyanisole-82,6-di-t-butyl-4-ethylphenol Note 2) The test criteria are as follows: be.

■ Initial contact resistance, contact resistance after combined test (average value of n = 5) ○: 25mΩ or less △: 25 to 50mmΩ Yes △: Corrosion products dotted ×: Corrosion points are observed on the entire surface has the advantage that it has a low contact resistance immediately after treatment, exhibits excellent corrosion resistance even in a harsh corrosive environment, and has stable contact performance without increasing contact resistance even with heat aging.

Claims (6)

[Claims] (1) A sealing solution for treating a copper-based or iron-based metal material plated with palladium or palladium alloy as an intermediate layer, and then plated with gold or gold alloy, which (A)
A pore-sealing treatment liquid comprising an organic solvent solution containing 0.1 to 3 wt% of paraffin wax 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 palladium or a palladium alloy 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 according to claim (1) or (2) is used. A pore sealing method characterized by processing. (5) After 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) The sealing material according to claim (1), (2) or (3) is made of a plating material in which a copper-based or iron-based metal material is plated with palladium or a palladium alloy as an intermediate layer, and then gold or a gold alloy is plated. A connector characterized in that the pores are sealed with a pore treatment liquid.