JPH0465496A - Flux-cleaning agent - Google Patents

Abstract

PURPOSE:To obtain the subject cleaning agent substitutable for conventional fluorocarbon-based or chlorine-based solvent having low toxicity and a high flash point without fear of ozone decomposition nor environmental pollution of water system containing a nonionic surfactant and a specific adipic acid ester as essential components. CONSTITUTION:The aimed cleaning agent for removing flux after soldering contains (A) preferably 1-30 wt.% polyoxyethylene-based nonionic surfactant such as preferably a polyoxyethylene alkyl ether or polyoxyethylene fatty acid ester and (B) preferably 50-99 wt.% at least a species of adipic acid ester expressed by the formula (R is 1-2C alkyl).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flux cleaning agent for removing flux applied during solder bonding to strengthen the bonding force between the solder and a base material after solder bonding.

[Conventional technology]

Conventionally, in the electrical and electronic industries, flux is applied in advance to firmly bond solder and base material in the printed circuit or printed wiring board manufacturing process. If this flux remains on the printed circuit or printed wiring board, it will cause poor conductivity or corrosion, so it is usually washed off with an organic cleaning agent after soldering. Freon 113 or methyl chloroform has conventionally been used as this cleaning agent. These solvents have a great ability to dissolve flux and are nonflammable, so they are widely used.

[Problem that the invention is trying to solve]

However, as society's awareness of environmental issues increases, there is a movement toward regulating the release of environmentally destructive substances into the atmosphere and water systems. For example, fluorocarbon solvents (5 types of specified fluorocarbons:
CFCII, CFCl2. CFCII3. C.F.
CI 14°CFCII5) and methyl chloroform,
Its use is being restricted as it is an ozone layer depleting substance.

Under these circumstances, industries that use Freon 113 or methyl chloroform are rapidly seeking flux cleaning agents that can replace these solvents.

[Means to solve the problem]

The present inventors have discovered that Freon 1 used in flux cleaning agents.
13 or as a result of repeated research on detergents to replace methyl chloroform, nonionic surfactants and compounds with the general formula (I) HOOC(CH2>4 CDOR(I) (wherein R is an alkyl group having 1 or 2 carbon atoms) A composition containing one or two types of adipate esters represented by (group) as an essential component has high cleaning performance and good finish comparable to conventional flux cleaning agents (Freon 113 and methyl chloroform). It was discovered that the cleaning agent exhibits the following properties, and based on this knowledge, the present invention was completed.

That is, the present invention provides: (1) a nonionic surfactant;
is an alkyl group having 1 or 2 carbon atoms) as an essential component.

The concentration of the nonionic surfactant used in the present invention is 1 to 30
Preferably, it is in the range of % by weight.

Examples of nonionic surfactants used in the present invention include polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, and polyoxyethylene oleyl ether; polyoxyethylene nonylphenyl Ether, polyoxyethylene alkylphenyl ether such as polyoxyethylene octylphenyl ether; polyoxyethylene polyoxypropylene block polymer, polyoxysorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, etc. polyoxyethylene derivatives; examples include sorbitan fatty acid esters and glycerin fatty acid esters. Although each of these can be used alone, a combination of two or more types is preferably used.

More preferably, a combination containing one or more polyoxyethylene-based nonionic surfactants such as polyoxyethylene alkyl ether or polyoxyethylene fatty acid ester is used. The number of moles of the ethylene oxide moiety added in the polyoxyethylene nonionic surfactant is preferably 3 to 40, more preferably lO to 40.
It is 20.

The concentration of adipate ester used in the present invention is 50
It is preferably in the range of 99% by weight.

Adipate esters used in the present invention include monomethyl adipate and monoethyl adipate. These may be used alone or in combination.

The combination of essential components in the present invention can be arbitrarily changed depending on the material and form of the object to be washed, the type of dirt, etc. If any one of the essential components is missing, the finish will deteriorate due to poor flux cleaning performance or water rinsing performance. In addition, by combining two essential ingredients, it is possible to obtain a practical cleaning agent that is safe for the environment, poses no problems in terms of occupational hygiene, and is comparable in cleaning ability to conventional fluorocarbon-based and chlorine-based fluxes. . Furthermore, it is possible to add various stabilizers and additives to the composition of the present invention in order to maintain the stability of the liquid and improve the stability against the objects to be washed, or to improve the dissolving power. Examples of stabilizers and additives include hydrocarbons, alcohols, ethers, acetals, esters,
Examples include ketones, fatty acids, nitroalkanes, amines, amides, glycols, aminoethanols, benzotriazoles, and the like.

Furthermore, it is also possible to add an anionic surfactant or a cationic surfactant to the composition of the present invention, if necessary.

〔Example〕

Hereinafter, the present invention will be specifically explained using Examples and Comparative Examples. The cleaning methods in Examples and Comparative Examples are as follows.

Cleaning method in Examples (Fig. 1) ■ Ultrasonic cleaner (manufactured by Yamado Scientific Co., Ltd., product name: BRANSONIC220) containing the composition of the present invention 2
A water rinsing tank (first tank, second tank) and two water rinsing tanks (third tank, fourth tank) were prepared, and the temperature of the washing tank was set to 40°C.

In addition, the temperature of the water rinsing tank was set to room temperature.

■ Apply various types of flux (manufactured by Tamura Seisakusho, product name: Flux F-2) to the item to be washed (glass epoxy printed circuit board).
30V and MH-320V) and melted solder bath (
Soldering was carried out at 260°C for 5 seconds.

■ The items to be washed were immersed in the first tank for 1 minute and then in the second tank for 1 minute to perform ultrasonic cleaning.

(2) Next, the items to be washed were sequentially immersed in the third tank and the fourth tank for 1 minute each, and the items to be washed were lightly shaken for water rinsing.

■ Finally, the items to be washed were dried in a dryer set at 110°C (drying time: 5 minutes).

■ Ion residue on the printed circuit board was measured using an omega meter.

Cleaning method in comparative example (Figure 2) (When volatile solvent is used) ■ Three hard glass washers (1st tank, 2nd tank, 3rd tank) with a capacity of 100 (W) equipped with cooling pipes Prepare 300 μl of comparative solvent in each type, set the first tank to a boiling tank (temperature at the boiling point of the comparative solvent), the second tank to a cold bath (room temperature), and the third tank to a steam tank (temperature at the boiling point of the comparative solvent). temperature).

■ Each item to be washed in the previous period was immersed in order for 1 minute (however, in the third tank, the items to be washed were placed in the steam layer).

■ Thereafter, the ion content remaining on the printed circuit board was measured using an omega meter.

In addition, when using a high-boiling solvent in the comparative example, the "cleaning method in the example" was followed.

Examples 1-5 A cleaning experiment was conducted on the compositions shown in Table 1.

The results are shown in Table 4.

Comparative examples 1 and 2 Cleaning experiments were conducted using the solvents shown in Table 2.

The results are shown in Table 4.

Comparative examples 3 and 4 Cleaning experiments were conducted using the solvents listed in Table 3.

The results are shown in Table 4.

Margins below [Effects of the Invention] The flux cleaning agent of the present invention has cleaning performance and finish quality comparable to conventional fluorocarbon-based and chlorinated solvents, and also does not destroy ozone and is biodegradable. Even if it gets mixed into wastewater, it can be easily decomposed by normal microbial treatment. Therefore, there is no need to worry about contaminating the aquatic environment due to wastewater. It is also a very safe cleaning solvent due to its low toxicity and high flash point.

Therefore, the flux cleaning agent of the present invention is practically an excellent flux cleaning agent that can replace conventional fluorocarbon-based and chlorinated solvents.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a method of cleaning an object to be washed using a cleaning agent of an example, and FIG. 2 is a schematic diagram of a method of cleaning an object to be washed using a volatile solvent of a comparative example. Patent applicant: Asahi Kasei Industries, Ltd.

Claims (2)

[Claims] (1) Nonionic surfactant, and (2) General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R represents an alkyl group having 1 or 2 carbon atoms) One or two types of adipate esters are required. A flux cleaning agent characterized by containing it as an ingredient.