JP2005105332A - Metal surface treating agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further improve the application effect of rust preventiveness etc., of a surface treating agent containing a polyoxyalkylene phenol ether derivative and to improve resistance to inclusion of an alkali. <P>SOLUTION: The metal surface treating agent contains at least one new polyoxyethylene alkyl phenol ether derivative expressed by general formula (1) and an acid. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a surface treatment agent for performing rust prevention of a metal material, and in particular, a polyoxyethylene alkylphenol ether derivative suitable as a discoloration prevention agent for silver, gold, copper, nickel, iron, aluminum, zinc or an alloy thereof. It is related with the surface treating agent containing.

  Polyoxyethylene alkylphenol is a nonionic surfactant and is widely used industrially as a cleaning agent, an emulsifier, an antistatic agent, an antifoaming agent, and a wet penetrating agent. When this type of compound is considered as a metal surface treatment agent, a hydrophilic part (polyoxyethylene part) that adsorbs to metal and a hydrophobic part that imparts hydrophobicity to the surface and functions such as water resistance (Alkylphenol part), and a patent for a silver discoloration inhibitor containing this as an active ingredient has been filed (Japanese Patent Publication No. 61-55596).

  We have also filed a patent application in which a compound in which an alkoxysilyl group is introduced into polyoxyethylene alkylphenol ether gives a highly durable metal surface treatment agent (Patent Document 2 Japanese Patent Laid-Open No. 10-195081). When this type of compound is combined with a long-chain alkyl mercaptan to produce an anti-discoloration agent such as silver, it is said that it exhibits two actions: an action of promoting the adsorption of the long-chain alkyl mercaptan to the metal and an emulsifying action. However, if the surface of the metal is treated with an aqueous surface treatment agent and the surface is washed with water, polyoxyethylene alkylphenol ether has high water solubility, so that a sufficient amount of adsorption of active ingredients cannot be obtained. In this case, the initial characteristics were good, but there was a risk of gelation due to hydrolysis condensation in an aqueous solution.

As a surface treatment agent that solves this problem, the present inventors have proposed a reaction product of a polyoxyalkylene alkylphenol ether and a phenyl isocyanate compound (Patent Document 3, Patent No. 3,382,852).
Japanese Patent Publication No. 61-55596 JP-A-10-195081 Japanese Patent No. 3382852

However, the surface treatment agent containing the polyoxyalkylphenol ether derivative has not been sufficiently satisfactory with respect to rust prevention. Particularly, in the case of a surface treatment agent further containing a mercapto compound in this derivative, the effect of the surface treatment such as rust prevention is extremely reduced when alkali is mixed in the treatment liquid.
The present inventors examined the cause of this, and found that the polyoxyethylene alkylphenol ether derivative of the surface treatment agent promoted adsorption of the alkyl mercaptan on the metal by mixing with alkali, and that the alkyl mercaptan can be added to the aqueous solution. It has been found that the effect of solubilization is significantly reduced. This phenomenon, polyoxyethylene alkyl phenols and hydrophilic groups possessed by the derivative (polyoxyethylene group), alkali OH ^- by the hydrogen bond, be hydrophilic they have is inhibited, precipitate in solution Inferred to be the cause.
It is also conceivable that the SH group of the alkyl mercaptan and the alkali component are neutralized to form an alkyl mercaptan ion and emulsify and precipitate in the solution. It is conceivable that the alkyl mercaptan in this form is relatively difficult to adsorb to the metal, and the original anti-discoloration effect has not been sufficiently exhibited.
The object of the present invention is to further improve the effect of imparting rust prevention and the like to the surface treatment agent containing the polyoxyalkylphenol ether derivative and to improve resistance to alkali contamination.

As a result of diligent investigation, the present inventor has found that adding an acid to a reaction product of a specific polyoxyethylene alkylphenol ether and phenyl isocyanate is effective in further improving rust prevention. And found the present invention.
That is, the present invention
(1) A metal surface treating agent comprising at least one kind of a novel polyoxyethylene alkylphenol ether derivative represented by the following general formula (1) and an acid;
(2) The metal surface treatment agent according to (1), further comprising at least one alkyl mercaptan and / or at least one polyoxyethylene surfactant.
(3) The present invention relates to a metal surface treatment method characterized by treating a metal with an aqueous solution of the metal surface treatment agent according to (1) or (2).

  According to the surface treating agent or the surface treating method of the present invention, rust prevention (discoloration prevention) is further improved by adding an acid to the reaction product of polyoxyethylene alkyl ether and phenyl isocyanate. In addition, the durability against alkali contamination can be improved. As a result, the service life of the treatment agent can be extended.

  The polyoxyethylene alkylene ether derivative used in the present invention is represented by the above general formula (1). In the above general formula (1), m is 1 to 20, preferably 8 to 12. In the general formula (1), n is 1 to 20, and 2 to 9 is preferable from the viewpoint of rust prevention. In addition, since it is difficult to obtain a single substance having the same n value in the synthesis of the polyoxyethylene alkylphenol ether compound, n has a certain distribution, and the n value shown in the following examples etc. is an integer value close to the average value. It is.

The polyoxyethylene alkylphenol ether derivative represented by the general formula (1) of the present invention includes a polyoxyethylene alkylphenol ether compound represented by the following general formula (2) and phenyl isocyanate represented by the following formula (3). It can be easily produced by reacting a compound at 20 to 100 ° C.

Examples of the compound represented by the general formula (2) include
Etc. are preferred.

  For the reaction of the polyoxyethylene alkylphenol compound and the phenyl isocyanate compound, an organic solvent such as ethyl acetate may be used. It is preferable to react 1 to 2 mol of phenyl isocyanate compound with respect to 1 mol of the polyoxyethylene alkylphenol ether compound of the general formula (2). The reaction time is about 30 minutes to 10 hours. A catalyst is preferably used for this reaction, whereby the reaction can be promoted. Examples of such a catalyst include dibutyltin laurate.

Particularly preferred examples of the polyoxyethylene alkylphenol ether derivative represented by the general formula (1) of the present invention are listed below.

  The acid used in the present invention may be an organic acid or an inorganic acid, and any acid can be used as long as it makes the bath of the surface treatment agent of the present invention acidic to pH 1-6. By adding an acid, it is possible to further improve the rust prevention property of the film formed on the metal surface by the polyoxyethylene alkylphenol ether derivative against the metal.

  When the metal surface treating agent of the present invention is described in more detail, the target metal is not particularly limited. For example, it is effective as a surface treatment agent for silver, gold, copper, iron, aluminum, zinc, and alloys thereof. However, it is more preferable to use it as a surface treatment agent for silver, gold and copper, and in particular, it is a surface treatment agent for copper foil used for electronic parts and printed circuit copper-clad laminates for silver plating and gold plating. When used as an (anti-discoloring agent), the effects of the present invention can be sufficiently exerted.

  In the metal surface treatment agent of the present invention, the polyoxyethylene alkylphenyl ether derivative is an aqueous solution or water containing at least one of alcohols such as methanol, ethanol and i-propanol, and ketones such as acetone and methyl isobutyl ketone. It is simple and preferable that the surface treatment is carried out by a method of diluting to 0.01 to 20% by a method such as soaking a metal in this solution.

  In addition, although this polyoxyethylene alkylphenol ether derivative may be used independently, you may mix with another rust preventive agent or a coupling agent, surfactant, etc. Another preferred rust inhibitor is alkyl mercaptan. The alkyl of the alkyl mercaptan preferably has 14 to 20 carbon atoms. A preferable surfactant is polyoxyethylene alkylphenyl ether. The alkyl of the polyoxyethylene alkylphenyl ether preferably has 8 to 12 carbon atoms, and the ethylene oxide of the polyoxyethylene alkylphenyl ether preferably has 5 to 12 added moles.

Example Synthesis of polyoxyethylene alkylphenyl ether derivative (1-1) A polyoxyethylene alkylphenol ether compound represented by the following formula (2-1) and phenyl isocyanate represented by the following formula (3-1). Synthesis of a compound represented by the following formula (1-1) by reaction.

One drop of dibutyltin laurate as a reaction catalyst was added to 9.68 g (0.02 mol) of a polyoxyethylene alkylphenol ether compound represented by the following formula (2-1), and the mixture was stirred and dissolved at room temperature. To this solution, 2.38 g (0.02 mol) of phenyl isocyanate represented by the following formula (3-1) was added dropwise over 10 minutes and reacted at room temperature for 1 hour. Thereafter, the temperature of the reaction solution was raised to 50 ° C., and the reaction was further continued for 1 hour and 30 minutes. The solution after the reaction was obtained as a clear and viscous liquid.

(1) Preparation of surface treatment liquid 0.04 g of the polyoxyethylene alkylphenol ether derivative represented by the formula (1-1) and 0.06 g of hexadecyl mercaptan were dissolved in 5 ml of isopropanol. This solution was added dropwise to 95 ml of pure water with stirring, and various acids shown in Table 1 below were further added until pH 2 to prepare a metal surface treatment solution.

(2) Evaluation of anti-discoloring property Bright silver plating with a thickness of about 5 μm was applied to an oxygen-free copper substrate (JIS 2.5 mm × 2 mm × 0.2 mmt). This silver-plated substrate was immersed in the surface treatment solution heated to 40 ° C. for 1 minute, then washed and dried to obtain a surface treatment substrate. This surface-treated substrate was immersed in a 0.2% ammonium polysulfide aqueous solution for 3, 10 and 30 minutes, and the degree of discoloration was visually evaluated. The evaluation results are shown in Table 1.
A: No discoloration ○: Discoloration is slightly (partially) Δ: Discoloration is entirely yellow.
X: The color changes to blue or black as a whole.

(3) Evaluation of resistance to alkali contamination To the surface treatment liquids of Examples 1 to 6 and Comparative Example 1 heated to 40 ° C., a 1NKOH solution was added to pH 12. After stirring for 30 minutes, the same acid as that added was added to pH 2. For the surface treatment solution of Comparative Example 1 to which no acid was added, the pH was adjusted to pH 2 with acetic acid after the KOH solution was added to pH 12. These surface treatment liquids were cooled to room temperature and allowed to stand, and the state of the surface treatment liquids when visually re-heated to 40 ° C. after 16 hours was visually observed. At the same time, the same discoloration prevention characteristics as in item (2) were evaluated. These evaluation results are shown in Table 2.



A: No discoloration ○: Discoloration is slightly (partially) Δ: Discoloration is entirely yellow.
X: The color changes to blue or black as a whole.

Claims (3)

A metal surface treating agent comprising at least one kind of a novel polyoxyethylene alkylphenol ether derivative represented by the following general formula (1) and an acid.
The metal surface treatment agent according to claim 1, further comprising at least one alkyl mercaptan and / or at least one polyoxyethylene surfactant. A metal surface treatment method comprising treating a metal with an aqueous solution of the metal surface treatment agent according to claim 1.