JPH04202695A - Sealing solution and sealing method - Google Patents

Abstract

PURPOSE:To produce a connector with an electrical contact having superior lubricity, corrosion preventiveness, etc., 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 an alkyl substd. naphthalenesulfonate 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 a sealing soln. This soln. contains 0.1-3wt.% paraffin wax and 0.1-3wt.% one or more kinds of alkyl substd. naphthalenesulfonates such as barium and calcium dinonylnaphthalenesulfonates 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 liquid for gold-plated electrical contacts, a sealing method, and a sealed connector contact. In particular, sealing liquids and sealants that provide long-term, stable, and excellent lubrication, rust prevention, and electrical connectivity for electrical contacts, especially under harsh conditions of use where wear and corrosion progress simultaneously due to repeated insertion and removal and vibration. The present invention relates to a hole processing 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 gold-saving 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 is reduced, the number of pin poles in the coating increases exponentially, resulting in a significant decrease in corrosion resistance.

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 known as rust preventive agents for iron-based metal materials and copper-based metal materials, and even before the introduction of gold-plated metals, they were used to lubricate gold-plated contacts. 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 should 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 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 development of automobile electronics, so-called car electronics, the number of gold-plated connectors for electronic circuits used in automobiles is increasing.

What are the contacts of automotive connectors?

In addition to being subjected to slight sliding wear caused by vibrations from the vehicle body, they are also exposed to extremely harsh corrosive environments such as various corrosive gases in the atmosphere in industrial areas, sea salt particles in coastal areas, and 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, 1 the present invention provides: (1) a sealing solution for treating a material 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 sealing method comprising an organic solvent solution containing 0.1 to 3 t% of paraffin wax and 0.1 to 3 t% of one or more types of (B) alkyl-substituted naphthalene sulfonates as essential components. Processing liquid.

(2) One or two chelate-forming cyclic nitrogen compounds
The pore-sealing treatment liquid according to (1) above, further containing 0.05 to 3 iit% of 1 or more species.

(3) The sealing solution according to (1) or (2) above, further comprising 0.001 to 1 νt% of one or more amine-based or phenolic 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 seal according to (1), (2) or (3) above is applied. A pore sealing method characterized by processing with a pore treatment liquid.

(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 method for sealing, characterized by treating with the sealing solution according to item 3).

(6) 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 the pore sealing described in (1), (2), or (3) above is used. This connector is characterized by having been sealed with a treatment liquid.

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 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, for steel etc. lanolin, petrolatum, grease,
Mineral oils are known to be used as rust preventive agents, but because these soft base oils are sticky, dust particles in the atmosphere can adhere to them, and when electrical contacts are repeatedly rubbed, they can damage the gold plating. This accelerates wear and at the same time reduces the sealing function and progresses corrosion, significantly shortening the life of 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. 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 an alkyl-substituted naphthalene sulfonate 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) A preferred example is Tachieha.

Dinonylnaphthalenesulfonate barium salt, dinonylnaphthalenesulfonate calcium salt, nonylnaphthalenesulfonate zinc salt, dinonylnaphthalenesulfonate barium basic salt, dinonylnaphthalenesulfonate ethylenediamine salt, dinonylnaphthalenesulfonate Examples include sodium foonic acid salt, lithium dinonylnaphthalene sulfonate salt, lead salt of dinonylnaphthalene sulfonate, ammonium salt of dinonylnaphthalene sulfonate, and triethanolamine salt of dinonylnaphthalene sulfonate. 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%. If it is less than 0.05 νt%, no effect of improving corrosion resistance can be obtained, and if it exceeds 3 wt%, it will have a negative effect on contact resistance.

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. A chelate-forming cyclic nitrogen compound is a compound that forms a stable chelate by coordinating with copper, nickel, etc. In particular, a cyclic nitrogen compound having a benzene ring,
Alternatively, triazine compounds are preferred. To give a specific example, the cyclic nitrogen compound having a benzene ring includes, for example, benzotriazole system ■ indazole system benzimidazole system indole system ■ (In each of the above formulas, R□ represents hydrogen, alkyl, or substituted alkyl, and R2 represents (representing an alkali metal, hydrogen, alkyl, substituted alkyl), etc.

Examples of benzotriazole systems include benzotriazole (both R1 and R2 are hydrogen), 1-methylbenzotriazole (R is hydrogen and R2 is methyl), 1- (N,
N-dioctylaminomethyl)benzotriazole (R
is hydrogen, R2 is N, N-dioctylaminomethyl),
Tolyltriazole (R1 is methyl, R2 is hydrogen), sodium tolyltriazole (R□ is methyl, R2 is sodium), etc. are preferred.

Examples of indazole series include indazole (R,
R2 are both hydrogen), 2-methylindazole (R is hydrogen, R2 is methyl), 2-benzylindazole (R is hydrogen, R2 is C, H, CR2), 1-acetylindacy-7L/ (Rz is Hydrogen, R2 is COCH) etc. 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 COC, H,) and the like are preferred.

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

Further, preferred specific examples of triazine compounds include, for example, 6-substituted-1,3;5-)-riazine-
2,4-dithiol-sodium salt (R is an amino group substituted with an alkyl group, preferably -N(C4H3)2
, -1~'(C,R07)2. -N(C1□H2,)z
, -NHC,H□, CH=CHC,l (,, etc.), cyanuric acid (2,4,6-1-lioxy 1.3
．． 5-triazine), melamine (2,4,6-)-lyamino-1,3,5-triazine), and the like. These are added singly or as a mixture of two or more, and together with paraffin wax, they provide corrosion resistance,
Improve durability. Its concentration is 0.05-3% in total
It%. Corrosion resistance is less than 0.05 wt%;
Durability is low, and if it is greater 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(CH,)3 2.2'-methylene-bis-(4-methyl-6-t-butylphenol) OH0H CH, CH3 2,2'-methylene-bis-(4-ethyl-6-t-butylphenol) CH2CH3CH2CH.

2.6 ~ Di-t-butyl-P-cresol H CH.

Butylated hydroxyanisole OCR, OCR.

2.6-di-7-butyl-4-ethylphenol H H2CH3 - and so on.

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 0.001 t%, this effect cannot be obtained, but if it exceeds 1 υt%, 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 with metal materials that have been sealed after plating, much of the sealing function is lost in the process of cleaning the press oil that adheres during subsequent press working, so 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.

Note that 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, and high nickel alloys can be appropriately selected according to the required performance of the connector, and there are no restrictions 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 mm. These were electroplated through a Reel Now 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 mmA and an open circuit voltage of 50 mnV. The corrosion test was conducted under the following conditions.

Gas composition: H2S 3±ippmS○2 10±
3ppm Temperature = 40±2℃ Humidity = 75±5%RH Time: 96 hours The combined test was performed by inserting and removing male and female terminals 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 the table are as follows.

A Paraffin wax 8-1 Dinonylnaphthalenesulfonate barium salt-2 Dinonylnaphthalenesulfonate calcium salt-3
Dinonylnaphthalene sulfonate zinc salt - 4 Dinonylnaphthalene sulfonate barium basic salt - 5 Dinonylnaphthalene sulfonate ethylene diamine salt - 6 Dinonylnaphthalene sulfonate sodium salt -
7 Dinonylnaphthalene sulfonic acid lithium 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-t,
-butylphenol) -42,2' -methylene-bis-(4-methyl-6-
t-butylphenol) -52,2'-methylene-bis=(4-ethyl-6-
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: It is.

■ Initial contact resistance, composite test micro contact resistance (average value of n = 5) 0: 25mmΩ or less△: 25-5011InΩ X: 50on+Ω or more ■ Appearance after corrosion test ◎: No corrosion products observed O: Corrosion products Traces present △: Corrosion products dotted ×: Corrosion points are observed on the entire surface [Effects of the invention] As described above, as an intermediate layer sealed by the present invention, after plating with palladium or palladium alloy, gold plating is performed. These contacts have similar contact resistance immediately after treatment, exhibit excellent corrosion resistance even in harsh corrosive environments, and have 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 palladium or palladium alloy as an intermediate layer, and then plated with gold or gold alloy, which (A)
A pore sealing solution comprising an organic solvent solution containing 0.1 to 3 wt% of paraffin wax and 0.1 to 3 wt% of one or more types of (B) alkyl-substituted naphthalene sulfonates as essential components. . (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 sealing solution according to (1) or (2) above, 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 seal according to (1), (2) or (3) above is applied. A pore sealing method characterized by processing with a pore treatment liquid. (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 method for sealing, characterized by treating with the sealing solution according to item 3). (6) 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 the pore sealing described in (1), (2), or (3) above is used. A connector characterized by having its pores sealed with a treatment liquid.