JPS62115097A - Methylchloroform composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a methyl chloroform composition for cleaning silver or materials containing silver such as silver-plated materials.

(Prior art) Methyl chloroform has a high dissolving power for oil and grease, is nonflammable, and has less toxicity than solvents such as trichlorethylene and perchlorethylene, and is useful for degreasing metals. It is widely used for cleaning, developing printed circuit board dry film, flux cleaning, and as a diluting solvent for aerosol products. However, methylchloroform alone has the disadvantage that it is relatively unstable and decomposition is significantly accelerated in the presence of metals, particularly aluminum. Once this decomposition reaction starts, it progresses in a chain-like fashion while generating hydrogen chloride, and the liquid becomes colored and eventually turns into a tar-like substance and black char.

In order to suppress this decomposition reaction and prevent corrosion of metals, stabilization of methyl chloroform is an essential requirement. Many proposals have been made to add the following, either singly or in combination.

It has been stabilized with the above-mentioned stabilizers and is currently commercially available.
Industrial grade methyl chloroform can be used without problems for cleaning many common metals, including aluminum, iron, zinc, and brass.

(Problems to be Solved by the Invention) However, silver-plated materials used as contact materials for electronic components are extremely susceptible to discoloration, even with the conventionally known stabilized methyl chloroform.

It is difficult to completely suppress discoloration. There is a method to suppress this discoloration by adding certain amines to methyl chloroform, but in this case, the amine itself is unstable and cannot be used for a long time. It also causes stains to adhere to the silver surface. For these reasons, methyl chloroform is not often used for cleaning metal materials containing silver.

(Elaborate means for solving the problem) The present inventors have repeatedly conducted research to improve the stability of methyl chloroform against silver.
By adding this and two or more substances selected from cyclic ethers, nitroalkanes, and epoxides, it is possible to immerse and steam clean silver or silver-containing materials such as silver-plated objects. However, we have discovered a practically stable methyl chloroform composition that does not cause the surface to discolor, cool, corrode, or even stain, and based on this knowledge, we have developed the present invention. It's arrived.

That is, 1. the present invention consists of methyl chloroform as a main component, sulfides or disulfides, and one or more substances selected from cyclic ethers, nitrodelcanes, and epoxides. The present invention provides a silver-stabilized methyl chloroform composition characterized by:

Examples of the stabilizer of the present invention include sulfides such as ter-butyl sulfide, 1so-propylethyl sulfide, and ethyl sulfide; disulfides such as dimethyl disulfide, diethyl disulfide, and di-15O-propyl disulfide; and cyclic ethers such as 1, 5-dioxane, 1.4-dioxane, 1.3-
Dioxalane, nitroalkanes such as nitromethane, nitroethane, nitrobutane, etc., and epoxides such as 1.degree. 2-butylene oxide, 2,3-butylene oxide, propylene oxide and the like.

The addition ratio of each stabilizer component in the present invention can be changed depending on the amount of impurities in methyl chloroform, the surface condition of the silver plated item to be washed, the cleaning method, the cleaning conditions, etc. The addition ratio of each stabilizer component to the total amount of the methyl chloroform composition is preferably within the following range.

Sulfides 0.0001-0.5% by weight Disulfides 0.0001-0.5% by weight - Cyclic ethers
1.0 ~15.0wt-nitroacitroalkanes ~10.0wt% Epoxides 0.1
~1 G, Omi% The composition of the present invention maintains sufficient stability against metals and silver even when used for a long time, and even in the presence of water or moisture, the composition of the present invention maintains sufficient stability against silver or silver plated objects. Discolors and brightens the surface of silver wave covering materials and structures such as
It is greatly improved over conventional compositions in terms of less corrosion.

In recent years, Ginmayu, which has been widely used as an excellent electrical contact material in the electronic and electrical industries including the semiconductor and IC fields, is extremely useful industrially as a cleaning solvent for silver-containing materials such as silver-plated items. It is of high value.

(Examples) The effects of the present invention will be specifically explained below using Examples and Comparative Examples. The discoloration test method and judgment method shown in Examples and Comparative Examples are as follows. Note that the weight ratio is based on the total amount of the methyl chloroform composition.

Discoloration test method Prepare 5 FC hard glass crack cleaning containers (41, 2, 3) equipped with cooling pipes with a capacity of 10,000 c, 1 is a boiling immersion tank, 2 is a cooling tank, and 3 is a steam cleaning tank. Use as a tank. Sample (methyl chloroform set paraboloid)'! To! 1.42
700cc for each, 300σ for 43, Ken 1. 3 is heated to a boiling state and &2 is held for about 20 CK. A steel plate with a thickness of J5111 is plated with nickel, and further,
A strip-shaped washing object (514a x 133 dragon) whose surface was silver-plated and pressed to a thickness of 1'5 μm was placed at 41.4
2.

Pour into the washing containers of &3 one after another and wash each tank for 10 minutes.

For items to be washed, the degree of discoloration is examined by visually observing the appearance of the silver-plated surface, and the presence or absence of stains on the silver-plated surface is examined using a microscope.

The degree of discoloration is ranked based on the following criteria.

Rank 1: Almost no discoloration.

Rank 2: There is a slight discoloration, but it is very slight.

Rank 3: Significant discoloration.

Rank 4: Significant discoloration.

2 Ink 5 Significant discoloration and blackening in some areas.

Example 1 1.2-butylene oxide 0.5% by weight, 1°4-dioxide 2.5% by weight, nitromethane 0.3% by weight,
A color change test was conducted on methyl chloroform containing ethyl sulfide o, o o o s weight fI.

The results are shown in Table 1.

Example 2 1.2-butylene oxide 0.5% by weight, 1°4-dioxide 2.5% by weight, nitromethane 0.3% by weight,
A color change test was conducted on methyl chloroform containing 0,000% by weight of dimethyl disulfide. The results are shown in Table 1.

Example 5 1.2-butylene oxide 0.5% by weight - 11°4-dioxide 2.5% by weight, nitromethane 0.5% by weight,
A friend who performs color change tests in tr methyl chloroform containing n-butyl sulfide o, o o o s weight tswo. The results are shown in Table 1.

Example 4 0.5% by weight of 1.2-butylene oxide, 2.5% by weight of 1°4-dioxide, 2l'l:l, T'l
:/ 0.5T4fi(%, 1so-Propylethyl sulfide A color change test was conducted on methyl chloroform containing 0.01% by weight. The results are shown in Table 1.

Example 5 1.2-butylene oxide O,S weight %, 1゜4-dioxide 2.5 weight i%, 2) lomethane J3 weight %
A color change test was conducted on methyl chloroform containing %, diethyl disulfide, o, o o s, weight %. The results are shown in Table 1.

Comparative Example 1 A discoloration test was conducted on methylchloroform containing 0.5% by weight of 1.2-butylene oxide, 2.5% by weight of 1°4-dioxide, and 0.3% by weight of nitromethane. The results are shown in Table 1.

Comparative Example 2 A color change test was conducted on methyl chloroform containing no stabilizer. The results are shown in Table 1.

Table 1 Test Results of Examples and Comparative Examples (Effects of the Invention) As is clear from Table 1, the methyl chloroform composition of the present invention does not maintain the surface of silver or silver plating vlJ1 even when washed at high temperature. There is very little discoloration.

Moreover, there is no adhesion of stains on the 6< surface, and it maintains practical optical stability. This is clearly an improvement over methyl chloroform compositions that do not contain the substance of the invention.

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Claims (1)

[Claims] Contains methyl chloroform as the main component, sulfides or disulfides, and cyclic ethers,
A methyl chloroform composition for cleaning silver or silver-containing materials such as silver-plated objects, characterized by comprising one or more substances selected from nitroalkanes and epoxides.