JPH04120198A - Rinsing - Google Patents

Abstract

PURPOSE:To prevent occurrence of ring-shaped stains and to shorten a drying time and a drying process in a de-fatting cleaning and flux cleaning by using an aqueous solution of alcohol having a specific composition and specific physical properties. CONSTITUTION:In a water rinsing process of de-fatting cleaning of metal, glass, ceramics, plastics, etc., or hung flux cleaning of printed board, hybrid IC, etc., an aqueous solution of an alcohol containing one or more of 2-5C alcohol and an alcohol content in an amount to give surface tension (25 deg.C) of aqueous solution of alcohol <=50dyne/cm (preferably <=40dyne/cm) is used in rinsing.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to a water rinsing process in degreasing and cleaning of metals, glass, ceramics, plastics, etc., or a water rinsing process in solder flux cleaning of printed circuit boards, hybrid ICs, etc. This relates to a rinsing method.

[Conventional technology]

Conventionally, metals,
Water is used for rinsing after degreasing and cleaning glass, ceramics, plastics, etc., or for rinsing after cleaning solder flux from printed circuit boards.

[Problem to be solved by the invention]

However, when simply rinsing with water, 1) ring-shaped stains occur due to water evaporation during drying, 2) it takes a long time to dry due to poor water drainage, and 3) the rinse water contains a large amount of dirty laundry. There was a problem in that a long rinsing process was required to bring out the water. In particular, in the field of cleaning parts with complex structures, precision parts that require high cleanliness, or surface-mounted printed circuit boards with many narrow gaps, water-based,
When a semi-aqueous cleaning agent is used, the above-mentioned problems are likely to occur, and a method to solve these problems is desperately needed.

[Means to solve the problem]

As a result of extensive research, the inventors of the present invention found that instead of rinsing with water during the degreasing or flux cleaning process,
It has been discovered that the above problems can be solved by rinsing with an alcohol aqueous solution containing an amount of a specific alcohol such that the surface tension of the aqueous solution is below a specific value, and the present invention has been completed.

That is, in the water rinsing step of degreasing cleaning or flux cleaning, the present invention includes at least one type of alcohol selected from alcohols having 2 to 5 carbon atoms, and the alcohol content lowers the surface tension of the alcohol aqueous solution by 50 dyne/cm.
This is a rinsing method after degreasing or flux cleaning, which is characterized by rinsing with an aqueous alcohol solution in an amount below (258C).

Examples of the alcohol having 2 to 5 carbon atoms used in the present invention include ethanol, n-propanol, isopropanol, n-propanol,
Butanol, 1so-butanol, 5ec-butanol, tert-butanol, n-amyl alcohol, 1s
o-amyl alcohol, 5ec-amyl alcohol, t
Examples include ert-amyl alcohol, 5ec-iso-amyl alcohol, 3-pentanol, 2-methyl-1-butanol, neopentyl alcohol, and the like.

The amount of these alcohols added to water is such that the surface tension of the alcohol aqueous solution is 50 dyne/Cm (25°C) or less, preferably 40 dyne/Cm (25°C) or less. This surface tension is 50 dyne/cm
The above is not preferable because it becomes difficult to drain the water after rinsing, and the amount of rinsing water contaminated with the washed items is increased. Moreover, if the amount of alcohol added to water increases, salts insoluble in alcohol derived from the detergent will precipitate, which is not preferable. From this point of view, it is preferable that the amount added to water is 5% by weight or less and the surface tension of the alcohol aqueous solution is 506y.
isopropanol, n-propanol, n-butanol, 1so-butanol, 5ec-butanol, n-amyl alcohol, which is less than ne/cm (258C),
1so-amyl alcohol and 5ec-amyl alcohol. More preferably, the amount added to water is 10% by weight or less and the surface tension of the alcohol aqueous solution is 40 dyne/
cm (25°C) or less, n-propertool, n-butanol, 1so-butanol, 5ec-butanol, n
-amyl alcohol, 1so-amyl alcohol, 5e
c-amyl alcohol.

The aqueous alcohol solution used in the present invention can also be used with the addition of a rust preventive agent to prevent metal from rusting.

Examples of such rust inhibitors include inorganic rust inhibitors such as chromates, nitrites, and phosphates, organic rust inhibitors such as various amines, benzotriazoles, carboxylates, and carboxylic acid amides, etc. can be mentioned.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Examples 1 to 6 and Comparative Example The following tests 1 to 3 were conducted using the alcohol aqueous solutions shown in Table 1. For comparison, water (72 dyne/c
A test was conducted using a temperature of 25°C.

1. Evaluation of the presence or absence of ring stains Stainless steel plates and glass plates that had been degreased and cleaned with a cleaning agent containing alkali salts and surfactants were rinsed by immersing them in the rinsing solutions 1 to 6 in Table 1 or in water. After drying with hot air at 80°C, the appearance was inspected to check for ring stains. The results are shown in Table 2.

2. Evaluation of the amount of rinsing water taken out After degreasing and cleaning 100 screws with a diameter of 2 mm and a length of 10 mm while keeping them in the cleaning basket, rinse them with rinsing water from 1 to 6 in Table 1 or with water. The liquid was drained for a minute, and the amount of rinsing water held in the screw-in cleaning basket was checked. The results are shown in Table 2.

3. Evaluation of drainability of rinsing water The flux-cleaned surface mount printed circuit board was
After rinsing with the rinse water of ~6 or with water, air blowing was performed to examine the time required to remove the rinse water. The results are shown in Table 2.

(Margin below) Relative value with drying time in the case of water as 1 [Effects of the invention] The rinsing method according to the present invention has the disadvantages of the conventional rinsing method using water. 2) It takes a long time to dry due to poor drainage, 3)
) This solves the problem of requiring a long rinsing process to remove a large amount of dirty rinsing water from the items to be washed.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. In the water rinsing step of degreasing cleaning or flux cleaning, at least one type of alcohol selected from alcohols having 2 to 5 carbon atoms is included, and the alcohol content is in an amount that makes the surface tension of the alcohol aqueous solution 50 dyne/cm (25 ° C.) or less. A rinsing method after degreasing or flux cleaning, characterized by rinsing with an aqueous alcohol solution.