JPS6026673A - Method for keeping copper and copper alloy from rusting - Google Patents

Abstract

PURPOSE:To form a chemical conversion coating having a significant rust preventing effect on the surface of copper by treating the surface with a soln. contg. specified 4,4-methylene-bis-(2-undecyl-5-methylimidazole) or a salt thereof. CONSTITUTION:4,4'-Methylene-bis-(2-undecyl-5-methylimidazole) represented by formula 1 or a salt thereof is dissolved in water, methanol, ethanol, isopropanol or other alcohol. The surfaces of copper parts are pickled or finished with sand paper, and the parts are immersed in the prepd. soln. The soln. may be coated or sprayed. The copper parts are then dried to form rust preventing films on the surfaces. The treated copper parts maintain their peculiar color tone and luster for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, the surface of copper or copper alloy is treated with a solution containing 4,4'-methylene-bis-(2-undecyl-5-methylimidazole) or a salt thereof at a temperature of 0 to 100°C. The present invention relates to a method for preventing rust of copper and copper alloys, which is characterized by contact treatment within a range to form a chemical conversion film on the surface of these metals.

The surface of copper or copper-containing metals gradually becomes contaminated in the atmosphere, and eventually loses its original color and luster and quickly turns brown, especially in atmospheres containing sulfur compounds such as hydrogen sulfide and carbon disulfide. be.

The above significantly reduces the commercial value of copper or metal products containing copper. The present inventors have discovered that by contact-treating the surface of copper or copper alloy with a solution containing 4,47-methylene-bis-(2-undecyl-5-methylimidazole) or a salt thereof represented by the following general formula, It was discovered that the anti-corrosion effect is impressive.

n C111123n C+i 11z3 Suitable solvents for carrying out the present invention are water or alcohols in the case of salts.

Alcohols are as follows. Methanol, ethanol, isopropanol, n-probanol, ethylene glycol, ethylene-glycol-mono-methyl ether. In the case of bisimidazole, the alcohols and chloroform or chlorocene (2) are used.

The salts used in the practice of this invention must also be water soluble. Such salts are formed from the bisimidazole and either organic or inorganic acids. The role of the acid is to dissolve the bisimidazole in water.

Therefore, any oxidizing acid can be used as long as it plays such a role.

When the bisimidazole salt comes into contact with copper metal, it forms a hisimidazole copper complex on the copper metal surface, which acts as a driving force to further form micelles, and finally the surface is covered with a bisimidazole film, which prevents this. Demonstrates the fruits of rust.

On the other hand, the acid component that has fulfilled its role (immediately dissociated) migrates into the aqueous solution.

Typical organic acids are acetic acid, glycolic acid, and oxalic acid.

Succinic acid and lactic acid are used, and hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid are used as inorganic acids.

Embodiments of the present invention will now be described. The surface of the copper alloy is finished by acid cleaning or sandpapering, and then it is immersed in a solution containing the bisimidazole or its salt. Or-? ;J: Instead of dipping, the solution may be applied or sprayed.

The above treatment can be carried out at a temperature in the range of 0 to 100°C, but it is easiest and most desirable to carry out it at room temperature.

The concentration of the solution mentioned above is 0.01 to 5.0 wt%, especially 0.01 to 5.0 wt%.
0.01 to 5.0 wt%, particularly preferably 0.1 to 2.0 wt%.

A treatment time of 1 minute or more is sufficient.

Post-treatment is performed in the order of washing with water and drying. Of course, washing with water can be omitted.

Next, the characteristics of the bisimidazole will be shown.

Melting point: 182-183°C V: 2925,2B55.1618,153
1,1465,1445.1420 (1st absorption) 1
375,1316,1037.91B,Σi33,71
3NMR (CD300) δ: 3.65. s, 211 (methylene group) i 2.
56. t, 411 (α-methylene); 2.00. s
, 611 (methyl group)i 1.6Lm, 411 (β
-methylene); 1.27. m, 3211 (undecyl group); 0.89. t, 611 (terminal αj^1 methyl of undecyl group) Mass: m/e 484 (M
Embodiments of the present invention will be specifically explained below using examples.

[Example 1] Commercially available 75% lactic acid was concentrated under reduced pressure to remove water, and the residue was dissolved in methanol to prepare a lactic acid methanol solution.

After adding 4'-methylene-bis(2-undecylimidazole) to the 1 jL solution until circle I reached 6.5, the solution was concentrated under reduced pressure to obtain an oily substance. This solidified by standing. The solidified product was repeatedly reconstituted with acetone three times to obtain the lactate salt of hisimidazole (m, p, 99-1
00°C). The NMR (CD30D) of lactate is as follows.

δ: 5.07. s, 2H (hydroxyl group of lactic acid); 4.
02. q, 2) 1 (α-proton of lactic acid); 3.
85. s, 2H (methylene group); 2.77, t, 4+
1 (α-methylene of undecyl group); 2.19.
s, 611 (5-position methyl group of imidazole); 1
．． 68. m, 411 (β-methylene of undecyl group)
; 1.27. m, 3211 (undecyl group);
0.89. t, 611 (terminal methyl of undecyl group) 3 cm wide, polished with sandpaper and degreased with Hensen.
A copper-clad laminate is immersed in an aqueous solution (slightly cloudy) consisting of 1 g of the lactate and 99 g of water at room temperature for 5 minutes, taken out, washed with water, dried, and left in the air until the surface changes color. The number of days (number of days of discoloration) was investigated.

Note that this observation was conducted at a location in a carbon disulfide manufacturing plant where an untreated control board would change color in one day. The number of days for discoloration was 30 days.

[Example 2] 1 g of the bisimidazole was added to 99 g, and 50 to (i
While stirring at 0'C, 1 mj2 of acetic acid was added to obtain a lactate aqueous solution having P113 or less. The solution was kept at 50-60°C, and a pretreated copper clad laminate as in Example 1 was added to it.
After being immersed for 1 minute, it was washed with water and dried.

The number of days for discoloration of this product was 25 days. That of the control piece was 1 day.

[Example 3] Dissolve 1 g of the bisimidazole in 99 g of ethanol,
The solution thus obtained was sprayed onto a copper clad laminate pretreated as in Example 1 at room temperature. The number of days for discoloration of this product was 30 days. That of the control piece was 1 day.

1. Indication of the case Patent Application No. 136647 filed in 1982 2. Name of the invention Rust prevention method for copper and copper alloys 3. Person making the amendment Relationship to the case: Patent applicant Minato-cho, Marugame City, Kagawa Prefecture 147-1 (763 TE108772-2-4111) 4, Detailed explanation of the invention column 5 of the specification to be amended, Contents of the amendment, page 4, lines 8-9, ``The concentration of the above solution is・・・
・is desirable. ” [The concentration of the above solution is 0.01
~5. Qi1t% is particularly preferably o,i~2.0 wt%. ”.

Written amendment to the above procedure (voluntary) June 29, 1980 Commissioner of the Japan Patent Office Kazuo Wakasugi 1. Description of the case 2. Name of the invention Rust prevention method for copper and copper alloys 3. Person making the amendment Relationship to the case: Patent Applicant 147-14, Minato-cho, Marugame City, Kagawa Prefecture, 1. Title of the invention in the specification subject to amendment, ``Claims'' Specification 1, Name of the invention Method for preventing rust of copper 2, Patent claims The surface of the copper is 4,4゛-methylene-bis-(2-undecyl-5-methylimidazole) represented by the following general formula.
Or its salt-containing solubility! The side characterized by contact treatment and forming a chemical conversion film on the metal surface! Rust prevention method General formula % Formula % 3. Detailed description of the invention The present invention uses 434゛-methylene-bis-(2
The present invention relates to a method for preventing rust on copper, which comprises contacting with a solution containing (undecyl-5-methylimidazole) or a salt thereof to form a chemical conversion film on the surface of the metal.

Copper surfaces gradually become contaminated in the atmosphere, eventually completely losing their original color and luster, and quickly turning brown, especially in atmospheres containing sulfur compounds such as hydrogen sulfide and carbon disulfide.

The above causes a significant decrease in the commercial value of copper metal products. The present inventors have demonstrated remarkable rust prevention by contact-treating the surface of copper with a solution containing 4,4゛-methylene-bis= (2-undecyl-5-methylimidazole) represented by the following general formula or a salt thereof. I found it to be very effective.

Suitable solvents for carrying out the invention are water or alcohols in the case of salts.

Alcohols are as follows. Methanol, ethanol, isopropanol, n-propanol, ethylene glycol, ethylene-glycol-mono-methyl ether. In the case of bisimidazole, the alcohols and chloroform or chlorocene (2) are used.

Salts suitable for the practice of this invention must be water soluble.

Such salts are formed from the bisimidazole and either organic or inorganic acids. The role of the acid is to dissolve the bisimidazole in water. Therefore, any acid that fulfills this role can be used.

When the bisimidazole salt comes into contact with copper metal, it forms a bisimidazole copper complex on the copper metal surface, which acts as a driving force to further form micelles, and finally the surface is covered with a bisimidazole film, which prevents the formation of bisimidazole copper complexes. Demonstrates rust effect.

On the other hand, the acid components that have fulfilled their role (ie, dissociated) migrate into the aqueous solution.

Typical organic acids used are acetic acid, glycolic acid, oxalic acid, succinic acid, and lactic acid, and inorganic acids include hydrochloric acid, sulfuric acid, phosphoric acid,
Nitric acid is used.

Embodiments of the present invention will be described next. The surface of the copper is finished by acid washing or sandpaper, and then immersed in a solution containing the bisimidazole or its salt.

Alternatively, the solution may be applied or sprayed instead of dipping.

The above treatment can be carried out at a temperature range of 0 to 100°C, but it is easiest and most desirable to carry out it at room temperature.

The concentration of the solution mentioned above is 0. Old~5. Especially from 0.1 to Owt%
2°0 wt% is desirable.

A treatment time of 1 minute or more is sufficient.

Post-treatment is performed in the order of washing with water and drying. Of course, washing with water can be omitted.

Next, the characteristics of the bisimidazole will be shown.

Melting point: 182-183°C NMR (CD30D > δ: 3.65.s, 211 (methyl L/n group): 2
．． 56. t, 4H (α-methylene): 2.00. s,
6H (methyl group): 1.6Lm, 411 (β-methylene): 1.2
7. m, 3211 (undecyl group): 0.89. t
, 6B (terminal methyl of undecyl group) Mass: m
/e 484 (M”), 329,357,343
, 249, 240 Hereinafter, embodiments of the present invention will be specifically explained with reference to Examples.

[Example 1] Commercially available 75% lactic acid was concentrated under reduced pressure to remove water, and the residue was dissolved in methanol to prepare a lactic acid methanol solution.

After adding 4.4'-methylene-bis-(2-undecyl-5-methylimidazole) to the warm solution until the pH reached 6.5, the solution was concentrated under reduced pressure to give an oily substance. This solidified by standing.

The solidified product was repeatedly reconstituted with acetone three times to obtain the lactate salt of bisimidazole (m, p, 99-100°C).

NMR (CD30D) of lactate is as follows.

δ: 5.0? , s, 211 (hydroxyl group of lactic acid):
4.02. q, 2H (α-proton of lactic acid): 3.
85. s, 211 (methylene group): 2.77, t
, 4H (α-methylene of undecyl group): 2.19
．． s, 6H (5-position methyl group of imidazole): 1.6
8. m, 411 (β-methylene of undecyl group):
1.27. in, 3211 (undecyl group): 0
．． 89. t, 6) 1 (Terminal methyl of undecyl group) A copper-clad laminate with a width of 3 am, polished with sand vapor and degreased with benzene, was placed in an aqueous solution (slightly cloudy) consisting of 1 g of the lactate and 99 g of water at room temperature for 5 minutes. The soaked cough plates were taken out, washed with water, dried, and left in the air to determine the number of days required for the surface to change color (number of days for discoloration).

This observation was conducted at a location in a carbon disulfide manufacturing plant where an untreated control board would change color within a day. The number of days for discoloration was 30 days.

[Example 2] 1 g of the bisimidazole was poured into 99 g of water, and 50 to 60
While stirring at °C, 11 Ill of acetic acid was added to obtain an acetate aqueous solution having a PI of +3 or less. The solution was maintained at 50 to 60 DEG C., and the copper-clad laminate pretreated as in Example 1 was immersed therein for 1 minute, then washed with water and dried.

The number of days for discoloration of this product was 25 days. That of the control piece was 1 day.

[Example 3] Dissolve 1 g of the bisimidazole in 99 g of ethanol,
The solution thus obtained was sprayed onto a copper clad laminate pretreated as in Example 1 at room temperature. The number of days for discoloration of this product was 30 days. That of the control piece was 1 day.

Claims (1)

[Claims] The surface of copper or copper alloy is formed by the following general formula 4,
0 to 100° with a solution containing 47-methylene-bis-(2-undecyl-5-methylimidazole) or its salt.
A general formula for a rust prevention method for copper and copper alloys, which is characterized by contact treatment in a temperature range of C to form a chemical conversion film on the surface of these metals.