JPH04314891A - Liquid and method for surface treatment - Google Patents

Abstract

PURPOSE:To give excellent soldering property, etc., stable for a long period to a copper-base metallic material provided with tin plating by using an org. solvent soln. containing specified proportions of petrolatum and metallic soap as a surface treating liquid. CONSTITUTION:An org. solvent soln. containing the following components is used as a surface treating liquid for a copper-base or iron-base metallic material provided with tin or tin alloy plating. This org. solvent soln. contains 0.1-5wt.% petrolatum and 0.05-5wt.% one or more kinds of metallic soaps as the essential components, and if necessary, it contains 0.05-5wt.% one or more kinds of chelate-forming cyclic nitrogen compds. and 0.001-1wt.% one or more kinds of amine or phenol antioxidants. The metallic soap is oxidized petrolatum metal salt, oxidized wax metal salt, etc., and these metals are Ca, Al, etc. As for the solvent, toluene, trichloroethylene, etc., is used. Thereby, the obtd. metallic material has excellent corrosion resistance, lubricating property, electric connecting property, etc., stable for a long period.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface treatment solution for tin and tin alloy plated materials, a surface treatment method, and a surface treated connector contact. In particular, the present invention relates to surface treatment liquids and surface-treated connector contacts that exhibit excellent lubrication, rust prevention, solderability, and electrical connectivity over a long period of time.

0002

2. Description of the Related Art Connectors are the most typical connecting parts for electronic equipment, and a wide variety of connectors have been put into practical use. BACKGROUND OF THE INVENTION As electrical products become smaller and more sophisticated, their electrical circuits become more precise and connectors become smaller. Typical surface treatments for connector contacts include plating with gold, silver, rhodium, nickel, tin, solder, and the like. In particular, tin and solder plating are inexpensive and are soft metals, but the oxide film is hard and easily peels off, so a new metal surface can be obtained by insertion and removal, so they are mainly used in consumer electronics.

0003

[Problems to be Solved by the Invention] However, it is known that the solderability of tin or solder-plated materials deteriorates over time, but there has hitherto been no method for suppressing this deterioration over time. In addition, it has low corrosion resistance and cannot be used in harsh environments.
White rust, etc. occurred, and the appearance and other characteristics were adversely affected. In addition, when it rubs against rolls and the like during processing steps such as slitting and pressing, powder is generated and scratches occur. In addition, vibrations and crimping during transportation and storage of the coil after winding may cause damage or material may adhere to the coil. Furthermore, the pressed products rubbed against each other after pressing, resulting in damage and fretting corrosion.

[0004] The present invention aims to provide a surface treatment liquid and a surface treatment method using the same that solves these problems, and also to provide a connector treated with the same. It is.

[0005]

[Means for Solving the Problems] In view of the above situation, the inventors of the present invention have conducted intensive research and as a result have come up with the following surface treatment liquid, method, and surface treated connector. That is, the present invention provides (1) a surface treatment liquid for treating a copper-based or iron-based metal material plated with tin or a tin alloy, which comprises (A) 0.1 to 5 wt% petrolatum and (B) metal. A surface treatment liquid comprising an organic solvent solution containing 0.05 to 5 wt% of one or more soaps as an essential component. (2) One or two chelate-forming cyclic nitrogen compounds
The surface treatment liquid according to (1) above, further comprising 0.05 to 5 wt% of at least one species. (3) The surface treatment liquid according to (1) or (2) above, further comprising 0.001 to 1 wt% of one or more amine-based or phenolic antioxidants. (4) A surface treatment method, which comprises plating a copper-based or iron-based metal material with tin or a tin alloy, and then treating it with the surface treatment solution described in (1), (2), or (3) above. (5) After pressing the copper-based or iron-based metal material plated with tin or tin alloy, the above (1), (2) or (3) is applied.
A surface treatment method comprising treating with the surface treatment liquid described above. (6) Made of copper-based or iron-based metal material plated with tin or tin alloy, as described in (1), (2) or (3) above.
A connector characterized in that the surface is treated with the surface treatment liquid described above.

Petrolatum, which is an essential component of the surface treatment 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 more normal paraffins, also contains 5-membered naphthenes, and has a lower melting point. Petrolatum is also known as one of the components of a rust preventive agent for steel, but in the present invention it functions as a base oil. That is, itself
A film is formed on the tin or tin alloy plating surface to prevent the plating surface from coming into contact with atmospheric moisture, oxygen, and various corrosive media.

In the present invention, the selection of this base oil is an important component for improving corrosion resistance and durability in combination with other components. And its concentration is 0.1wt
If it is less than %, corrosion resistance and durability will be reduced, making it impossible to obtain the desired effect. On the other hand, if it is more than 5 wt%, the contact resistance will increase and it will be useless as a surface treatment for contacts, and uneven coating will occur, which is not preferable.

Another essential component of the surface treatment liquid of the present invention is metal soap. Preferred examples of the metal soap used in the present invention include petrolatum oxide metal salts, oxidized wax metal salts, stearate metal salts, laurate metal salts, ricinolenic acid metal salts, myristate metal salts, oleate metal salts, These include naphthenic acid metal salts and lanolic acid metal salts. Further, the metal salt is not particularly limited, but preferably Ca, Al, Ba, Pb salts and the like.

[0009] These may be used alone or in combination of two or more in a total amount of 0.05 to 5 wt%. 0.05wt%
If it is less than 5 wt %, the effect of improving corrosion resistance cannot be obtained, and if it exceeds 5 wt %, an adverse effect on contact resistance is observed.

Furthermore, a chelate-forming cyclic nitrogen compound; an amine-based or phenol-based antioxidant may be added to the surface 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, as a benzotriazole type, the following general formula 1 is used.

[Chemical formula 1] As an indazole type, the following general formula 2

[Case 2] As a benzimidazole type, the following general formula 3

[Chemical formula 3] As an indole type, the following general formula 4

embedded image (In each of the above formulas, R1 represents hydrogen, alkyl, or substituted alkyl, and R2 represents an alkali metal, hydrogen, alkyl, or substituted alkyl).

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

Examples of the indazole type include indazole (R1 and R2 are both hydrogen), 2-methylindazole (R1 is hydrogen and R2 is methyl), 2-benzylindazole (R1 is hydrogen and R2 is C6H5CH2), and 1-acetylindazole. (R1 is hydrogen, R2 is COCH3)
etc. are preferred.

Examples of the benzimidazole type include benzimidazole (both R1 and R2 are hydrogen), N-acetylbenzimidazole (R1 is hydrogen, and R2 is COCH).
3), N-benzoylbenzimidazole (R1 is hydrogen, R2 is COC6H5), etc. are preferred.

Preferred examples of the indole type include indole (R1 and R2 are both hydrogen), indole-1-carboxylic acid (R1 is hydrogen and R2 is COOH), and 1-methylindole (R1 is hydrogen and R2 is CH3). .

Preferred specific examples of triazine compounds include the following general formula 5 as 6-substituted-1,3,5-triazine-2,4-dithiol-sodium salt.

embedded image (R represents an amino group substituted with an alkyl group, such as -N(C4H9)2, -N(C8H17)2, -N
(C12H25)2, -NHC8H16CH=CHC8
H17 etc. are preferred. ), the following general formula 6 as cyanuric acid (2,4,6-trioxy-1,3,5-triazine)

[Chemical formula 6] Melamine (2,4,6-triamino-1,3,5-triazine) has the following general formula 7

[C7] It is.

[0016] These are added singly or in a mixture of two or more to improve corrosion resistance and durability together with petrolatum. Its concentration is 0.05-5 wt% in total. 0.0
If it is less than 5 wt%, corrosion resistance and durability will be low;
If it is larger than wt%, electrical connectivity will be impaired.

[0017] The above-mentioned amine-based or phenol-based antioxidant which may be added as necessary to the surface treatment liquid of the present invention is, for example, P,P'-dioctyl diphenylamine represented by the following general formula 8.

[Chemical formula 8] The following general formula 9 as 4,4'-tetramethyldiaminodiphenylmethane

[Chemical Formula 9] The following general formula 10 as 4,4'-methylene-bis-(2,6-di-t-butylphenol)

[Chemical formula 10] 2,2'-methylene-bis-(4-methyl-6-t-butylphenol) is represented by the following general formula 11.

[Chemical formula 11] The following general formula 12 as 2,2'-methylene-bis-(4-ethyl-6-t-butylphenol)

[Chemical formula 12] The following general formula 13 as 2,6-di-t-butyl-p-cresol

[Chemical formula 13] As butylated hydroxyanisole, the following general formula 14

[
14] The following general formula 15 is used as 2,6-di-t-butyl-4-ethylphenol.

[Chemical formula 15] etc. can be mentioned.

[0018] These include one or more types at a concentration of 0.001
~1 wt% can be added. By adding these components, durability can be further improved. In other words, the function of the surface treatment film is stabilized over a long period of time,
It also has the effect of suppressing film deterioration in high-temperature environments. 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.

The surface treatment liquid has the above-mentioned components, but 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.

[0020] As a treatment method, any method may be used, such as immersing the plated product in a surface treatment liquid, or spraying or applying the surface treatment liquid. However, in the present invention, regardless of whether the shape of the plated product is a plate, strip, or pressed part, if it is immediately after plating, that is, on a continuous line,
It has been found that processing within this line is highly effective in enhancing various functions of surface treatment.

Furthermore, it is also effective to surface-treat the plated product with the surface treatment solution of the present invention after press working. Even with metal materials that have been surface-treated after plating, many of the functions of the surface treatment are lost in the process of cleaning press oil adhering during subsequent press working, so re-surface treatment becomes effective.

[0022] In the subsequent connector processing process,
If there is a cleaning process for the plated product until the final assembly of the electronic device, the surface treatment function will be lost as well, so it is effective to perform the surface treatment according to the present invention as appropriate. Furthermore, even when incorporated into electronic equipment as a connector and used in actual use, if the contact performance deteriorates with use, it can be treated with an appropriate surface treatment liquid. Therefore, the present invention also includes connectors treated with the surface treatment liquid of the present invention.

In the present invention, the metal material serving as the plating base material may be copper, various copper alloys such as brass, phosphor bronze, titanium copper, iron, stainless steel, high nickel alloy, etc., as appropriate according to the required performance of the connector. You can choose and there are no restrictions. For base plating, copper, nickel, etc. can be used as appropriate.
There are no restrictions whatsoever. Tin or tin alloy plating is done by acid bath,
It also includes matte plating, bright plating, and reflow plating from an alkaline bath.

[0024]

[Examples] The present invention will be explained in more detail with reference to Examples below. Thickness of phosphor bronze (C5210) for springs: 0.2m
Male and female continuous terminals were each press-molded using a cold-rolled material of 500 mm. This was electroplated through a reel-to-reel continuous electroplating line. In the plating line, after degreasing and pickling, various platings of reflow tin, reflow solder, and bright solder were applied to a thickness of 1.5 μm, and the surface treatment was performed by immersing it in various surface treatment solutions using trichloroethane as a solvent. . The thus surface-treated male and female terminals were cut from the carrier portion and lead wires were crimped to prepare test materials. These test materials were subjected to a salt spray test (JISZ 2731-1988) for 48 hours to evaluate their corrosion resistance. Further, the solderability of the material after the salt spray test was tested in accordance with JIS C 0050-1985 (no aging, method 1), and evaluated by the solder wetted area. In addition, the contact resistance of the material after the salt spray test was measured using a four-terminal method. Further, the male and female connectors were fitted together and fixed on a vibrator, and after operating the vibrator for 1 hour, the connector was pulled out and the vibration resistance was evaluated based on the appearance of the contact portion. The contact resistance of the material was measured after being vibrated with a vibrator for 1 hour. Contact resistance measurements were conducted under the following conditions. Load: 0.1N Sliding speed: 0.02mm/sec Sliding distance: 2mm Measurement points: 200 The results are shown in Table 1.

[Table 1] Note 1) However, the abbreviations of the surface treatment liquids in the table are as follows. A Petrolatum B-1 Petrolatum oxide Ca salt-2 Oxidized wax Ca salt-3 Stearic acid Ca salt-4 Lauric acid Al salt-5 Ricinolenic acid Al salt-6 Myristic acid Ca salt-7 Oleic acid Ca salt-8 Naphthenic acid Ca salt Salt-9 Lanolic acid Al salt C-1 Benzotriazole-2 Indazole-3 Benzimidazole-4 Indole-5 1-methylbenzotriazole-6 Tolyltriazole-7 Sodium tolyltriazole-8 1-(N,N-dioctylamino Methyl)benzotriazole-9 Melamine D-1 P,P'-dioctylphenylamine-2
4,4'-tetramethyldiaminodiphenylmethane-3 4,4'-methylene-bis-(2,6-di-t
-butylphenol) -4 2,2'-methylene-bis-(4-methyl-6
-t-butylphenol) -5 2,2'-methylene-bis-(4-ethyl-6
-t-butylphenol) -6 2,6-di-t-butyl-p-cresol-7
Butylated hydroxyanisole-8 2,6-di-t-butyl-4-ethylphenol Note 2) The test criteria are as follows. ■ Appearance after salt spray test ○: No white rust ×: White rust ■ Solderability (n = 5) ○: Solder wet area is 98% or more ×: Solder wet area is less than 98% ■ After salt water spray test Contact resistance, contact resistance after vibration ○: Maximum contact resistance is less than 20 mΩ ×: Maximum contact resistance is 20 mΩ or more ■ Vibration resistance ○: No wear is observed ×: Wear is observed

[0025]

As described above, the tin or tin alloy contacts surface-treated according to the present invention have excellent solderability immediately after treatment, and excellent corrosion resistance and solderability even in a severe corrosive environment. Furthermore, it is possible to suppress the appearance defects such as fretting corrosion caused by adhesion of tin and the occurrence of contact defects in contacts.

Claims (6)

[Claims] [Claim 1] A surface treatment liquid for treating a copper-based or iron-based metal material plated with tin or a tin alloy, comprising:
A surface treatment liquid comprising an organic solvent solution containing as essential components 0.1 to 5 wt % of (A) petrolatum and 0.05 to 5 wt % of one or more metal soaps (B). 2. The surface treatment liquid according to claim 1, further comprising 0.05 to 5 wt % of one or more chelate-forming cyclic nitrogen compounds. 3. The surface treatment liquid according to claim 1, further comprising 0.001 to 1 wt % of one or more amine-based or phenolic antioxidants. 4. A surface treatment method, which comprises plating a copper-based or iron-based metal material with tin or a tin alloy, and then treating the material with the surface treatment solution according to claim 1, 2, or 3. [Claim 5] After pressing a copper-based or iron-based metal material plated with tin or a tin alloy, claim 1, 2 or 3
A surface treatment method comprising treating with the surface treatment liquid described above. [Claim 6] The material is made of a copper-based or iron-based metal material plated with tin or a tin alloy, and claims 1, 2, or 3
A connector characterized in that the surface is treated with the surface treatment liquid described above.