JPH04193984A - Sealing solution and method - Google Patents

Abstract

PURPOSE:To improve lubricity and corrosion resistance and to reduce contact resistance by treating a metallic material plated with Ni, Pd and Au with an org. agent soln. contg. petrolatum and an alkyl-substituted naphthalene sulfonate as the essential components. CONSTITUTION:An org. solvent soln. contg., by weight, 0.1-3% petrolatum and 0.05-3% of >=1 kind selected from alkyl-substituted naphthalene sulfonates as the essential components is prepared, or a sealing soln. contg. 0.05-3% 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 an Au (alloy) plating thereon is treated with the sealing soln. to seal pinholes.

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 contact. In particular, the present invention relates to a sealing liquid, a sealing method, and a sealed connector that exhibit excellent long-term stability in lubrication, 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 level of reliability, such as computers and communication equipment, are made of spring steel 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 ministerial measures have been taken to reduce the cost of 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. 3. Therefore, after plating a nickel base, palladium or palladium alloy is plated as an intermediate plating, and then gold plating is used. However, even this three-layer 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 nickel is plated as the base layer and palladium or palladium is plated as the intermediate layer. There are no known sealing liquids or sealing methods for materials plated with palladium alloy and gold plated thereon.

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

In such a situation, among the above properties (■) to (■), corrosion resistance (■) is good for industrial gas (H2S, So2 mixture) and salt water spray resistance, and (■) is good for corrosion resistance under harsh temperature and humidity cycle environments. There is now a need for a sealing liquid technology that has significantly improved durability compared to conventional sealing treatments and has other properties that are equivalent or better.

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 the above 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.

(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) Petrolatum 0.1-3
A pore-sealing treatment liquid comprising an organic solvent solution containing as essential components 0.05 to 3 wt% of one or more of (B) alkyl-substituted naphthalene sulfonates.

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

(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 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, the above (1), (2) or (3) A pore-sealing method characterized by treating with the pore-sealing solution described in (3).

(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 apply ) A pore-sealing treatment method characterized by treating with the pore-sealing treatment liquid described in .).

(6) It consists of a copper-based or iron-based metal material plated with nickel as a base layer, palladium or palladium alloy as an intermediate layer, and then plated with gold or gold alloy, and is made of a plating material that is plated with gold or gold alloy as described above (1), (2) or ( 3) A connector characterized by being sealed with the sealing solution described above.

Petrolatum, which is an essential component of the pore sealing solution of the present invention, is a jelly-like semisolid wax obtained from petroleum, and is an ointment-like petroleum wax obtained from the vacuum distillation residue by solvent dewaxing, centrifugation, etc. Compared to paraffin wax, it contains less normal paraffins and more isoparaffins, and also contains 5-membered ring naphthenes, so it has a low melting point. Petrolatum is well-known as one of the components of a rust preventive agent in steel, but in the present invention it has a function as a base oil, that is, it itself has a gold-plated surface with many pinholes. This prevents atmospheric moisture, oxygen, and various corrosive media from coming into contact with the nickel base through pinholes and other microscopic defects in the gold plating.

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 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 an alkyl-substituted naphthalene sulfonate represented by the following formula.

5O1 (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 include, for example.

Dinonylnaphthalenesulfonate barium salt, dinonylnaphthalenesulfonate calcium salt, dinonylnaphthalenesulfonate zinc salt, dinonylnaphthalenesulfonate barium basic salt, dinonylnaphthalenesulfonate ethylenediamine salt, dinonylnaphthalene Examples include sodium sulfonate 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 wt%, no effect of improving corrosion resistance can be obtained, and if it exceeds 3 wt%, an adverse effect on contact resistance is observed.

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-based N, indazole-based benzimidazole-based octa-indole-based (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 (Rz-Rz are both hydrogen), 1-methylbenzotriazole (R1 is hydrogen, R2 is methyl), 1-(N, N
-dioctylaminomethyl)benzotriazole (R1
is hydrogen, R2 is N, N-dioctylaminomethyl), tolyltriazole (R is methyl, R2 is hydrogen), sodium tolyltriazole (R is methyl, R2
is preferably sodium).

As an indazole type, for example, indazole (R
2 are both hydrogen), 2-methylindazole (R is hydrogen, R2 is methyl), 2-benzylindazole (R is hydrogen, R2 is C, H, CH,), 1 1-acetylindazole (R is hydrogen) , R2 is c.

CM, ) etc. are preferred.

As a benzimidazole type, for example, benzyl
Imidazole (both R and R2 are hydrogen), N-acetiibenzimidazole (R is hydrogen, R2 is C○CH,) +
N-benzoylbenzimidazole (R□ is hydrogen, R
2 is co c g Hs), etc. are preferred.

Examples of indole series include 1, for example, indole (R1, R2
(both are hydrogen), indole-1-carboxylic acid (R is hydrogen, R2 is C00H), 1-methylindole (R□ is hydrogen, R2 is CH,), and the like are preferred.

Further, specific examples of triazine compounds include 6-substituted-1,3,5-triazine-2,4-dithiol-sodium salt (R is an amino group substituted with an alkyl group, preferably - N(C,R9)2.-N(C,H?),,-N(
C hzHzs)z,NHC,H,,CH=CHC,H
, etc.) cyanuric acid (2,4,6-trioxy-
1,3,5-triazine), and melamine (2,4,6-triamino-1,3,5-triazine). These are added singly or as a mixture of two or more to improve corrosion resistance and durability together with paraffin wax. Its concentration is 0.05-3wt% in total
It is. If it is less than 0.05 tit%, corrosion resistance and durability will be low, and if it is more than 3 vt%, 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-tert-butylphenol) (CH,), CC(CH,).

2.2'-Methylene-bis-(4-methyl-6-butylphenol) CH2Cl.

2.2'-Methylene-bis-(4-ethyl-6-butylphenol) OH0H CH2Cl, CH2Cl.

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

Butylated hydroxyanisole OH0H QC)l, OCH.

2.6-di-t-butyl-4-ethylphenol H CH, CH.

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 0.001 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 blank, 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 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.

In addition, in the present invention, the metal material serving as the plating base material is:
Copper, various steel alloys such as brass, phosphor bronze, titanium steel, iron, stainless steel, high nickel alloy, etc. can be selected as appropriate according to the required performance of the connector, and there are no restrictions in any way. 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 cold-rolled spring material of phosphor bronze (C5210) with a thickness of 0.2 m+. 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 in neutral palladium-nickel alloy plating bath, and 0.1 μm gold plating in acid 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.

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 DC of 10 mmA and an open circuit voltage of 50 aoV. The corrosion test was conducted under the following conditions.

Gas composition: H2S 3±lppm5o2 10±
3pprn Temperature: 40±2°C Humidity: 75±5%RH Time: 96 hours The heating test was held at 125°C in the atmosphere for 1000 hours.

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 petrolatum B-1 dinonylnaphthalene sulfonate barium salt-2
Dinonylnaphthalenesulfonate calcium salt - 3 Dinonylnaphthalenesulfonate zinc salt - 4 Dinonylnaphthalenesulfonate barium basic salt - 5 Dinonylnaphthalenesulfonate ethylene diamine salt - 6 Dinonylnaphthalenesulfonate sodium salt -7
Dinonylnaphthalenesulfonic acid lithium salt C-1 Benzotriazole-2 Indazole-3 Benzimidazole-4 Indole-51-Methylbenzotriazole-6 Tolyltriazole-7 Sodium tolyltriazole-81-(N,N-dioctylaminomethyl) Benzotriazole-9 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-
-butylphenol) -52,2'-methylene-bis-(4-ethyl-6-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 heating test (average value of n = 5) Q: 25 mo + Ω or less △: 25 to 50 mm Ω X: 50 mm Ω or more ■ Appearance after corrosion test ◎: No corrosion products observed ○: Corrosion products Traces present Δ Corrosion products dotted ×: Corrosion points are observed on the entire surface [Effects of the invention] As described above, nickel plating is used as the base layer sealed by the present invention, and palladium or palladium alloy plating is used as the intermediate layer. Gold-plated contacts have the advantage of low contact resistance immediately after treatment, excellent corrosion resistance even in harsh corrosive environments, and stable contact performance with no increase in contact resistance due to thermal history. have

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) Petrolatum 0.1-3
1. A pore-sealing solution comprising an organic solvent solution containing as essential components 0.05 to 3 wt% of one or more of (B) alkyl-substituted naphthalene sulfonates. (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 a copper-based or iron-based metal material with nickel as a base layer, palladium or a palladium alloy as an intermediate layer, and then electroplating gold or a gold alloy thereon, claims (1) and (2) Or (3) A pore-sealing method characterized by treating with the pore-sealing solution described in (3). (5) After plating nickel as a base layer, plating palladium or palladium alloy as an intermediate layer, and pressing a copper-based or iron-based metal material plated with gold or gold alloy, claim (1), (2) or ( 3) A method for sealing, characterized by treating with the sealing solution according to item 3). (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 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.