JPH04127956A - How to clean the surface of an article - Google Patents

Abstract

PURPOSE:To wash various kinds of articles without generating so-called environmental problems, such as environmental pollution and destruction of the ozone layer, as a washing liquid to be used does not contain chlorine atoms by bringing terpene alcohol into contact with the articles stuck with contaminating materials to dissolve away the contaminating material, then rinsing the articles with hydrogen-contg. halogenated hydrocarbon. CONSTITUTION:The terpene alcohol is brought into contact with the articles stuck with the contaminating materials to dissolve away the contaminating materials and, thereafter, the articles are rinsed with the hydrogen-contg. halogenated hydrocarbon. The hydrogen-contg. halogenated hydrocarbon is 1 to 3C and has 25 to 100 deg.C b.p. The hydrogen-contg. halogenated hydrocarbon to be used as the rinsing liquid is easily decomposed in the atm. and, therefore, hardly arrives at the stratosphere and has the less influence on the ozone layer.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for cleaning the surface of an article, and more particularly to a cleaning method particularly suitable for cleaning rosin flux used for soldering printed wiring boards. . The method of the present invention is also useful for cleaning and removing contaminants such as oils, waxes, greases, greasy abrasives, and the like.

Prior art and its problems IC parts and other parts are attached to a printed wiring board by soldering, and flux is used to improve soldering properties.

Fluxes are broadly classified into rosin-based fluxes and non-rosin-based or water-soluble fluxes. Among these, rosin-based fluxes are widely used in the electronic industry for mounting IC parts and other parts onto printed wiring boards. Soldering is undesirable because if rosin-based flux remains afterwards, the resistance of the wiring board will decrease, causing circuit damage.

Therefore, washing removal of rosin flux is 1°1.1-
) Chlorinated hydrocarbons such as dichloroethane, trichlorethylene, dichloroethane, chlorinated fluorinated hydrocarbons such as trichlorotrifluoroethane (Freon 113), dichlorotetrafluoroethane, mixtures thereof, or azeotropic mixtures of these and other organic solvents It has been done using nato.

In particular, Freon 113 is nonflammable, has low toxicity, and has excellent chemical stability. It does not corrode printed wiring boards equipped with parts such as metals, plastics, and elastomers, and selectively removes only contaminants. It has been widely used because of its excellent removal properties.

Water is also used in some cases to wash and remove water-soluble flux.

Problems to be Solved by the Invention However, in recent years, certain types of chlorofluorocarbons (fluorocarbons) and chlorinated hydrocarbons have been released into the atmosphere, destroying the ozone layer in the stratosphere, and as a result, causing damage to the earth, including humans. It has been pointed out that this has a serious negative impact on the ecosystem above.
The use and production of chlorinated fluorinated hydrocarbons and chlorinated hydrocarbons, which have a high possibility of depleting the ozone layer, has been restricted.

On the other hand, when washing and removing water-soluble flux with water, the surface tension of the water is high, so cleaning of minute parts may not be sufficient. Sometimes "stains" remain and cause electrical problems. In addition, cleaning and removing flux with water is not widely practiced because expensive equipment is required for purifying the water used for cleaning and for treating waste water after use.

Terpene alcohol is known as a solvent for rosin flux (Japanese Unexamined Patent Publication No. 58-66323), but it has not been used as a flux cleaning agent after soldering. This is because the terpene alcohol remains on the surface of the article after flux cleaning due to its high viscosity and boiling point of 200°C or higher, making it extremely difficult to remove. For example, terpene alcohols are insoluble in water and cannot be removed by rinsing with water.

Means for Solving the Problems As a result of repeated research in view of the current state of the technology as described above, the present inventor has found that when cleaning with terpene alcohol and rinsing with hydrogen-containing halogenated hydrocarbon are used together, the conventional technology It has been found that the above problems are significantly reduced or substantially eliminated.

That is, the present invention provides the following method for cleaning the surface of an article: ■ After bringing a terpene alcohol into contact with an article to which a contaminant has adhered to dissolve and remove the contaminant, the article is treated with hydrogen-containing halogenated carbon. A method for cleaning the surface of an article, characterized by rinsing with hydrogen.

■Hydrogen-containing halogenated hydrocarbon has 1 to 3 carbon atoms and 25
The method for cleaning the surface of an article according to item (1) above, which has a boiling point of ~100°C.

Terpene alcohols used in the present invention include natural and synthetic ones, and more specifically, the following are exemplified.

(a) Chain terpene alcohol; *linalool (C1oH180), boiling point = 197-99
8C *Geraniol (C1oH+aO), n point = 229~
308C *Citronellol (C10H200), boiling point -225
269C (b) Monocyclic terpene alcohol; *α-terpineol (C+oH+sO), boiling point = 2
17-218°C *β-terpineol (C1oH180), boiling point = 20
9-210℃ *γ-terpineol (C+oH+sO) *Menthol (C1oH180), boiling point = 216℃*Cineol (C
1oH180), boiling point = 176°C These terpene alcohols can be used alone or as a mixture of two or more.

In addition, terpene alcohol contains terpene hydrocarbons, organic solvents, preservatives, etc. within a range not exceeding 10% of its weight.
A stabilizer or the like may be added. When adding terpene hydrocarbons or organic solvents, effects such as viscosity reduction, freezing point depression, etc. are achieved.

Examples of hydrogen-containing halogenated hydrocarbons used as a rinsing liquid after cleaning with terpene alcohol in the method of the present invention include the following.

*1.1.2-Trichloro-2,2-difluoroethane (R-122), boiling point = 72°C *1,1-dichloro-
2,2,2-)rifluoroethane (R-123), boiling point = 27°C *1,2-dichloro-2,2-difluoroethane (R-
132b), boiling point = 47°C *1,1-dichloro-1-fluoroethane (R-141b)
), boiling point = 32°C *1-chloro-2,2-difluoroethane (R142)
, boiling point -35°C *1.1-Dichloro-2,2,3,3,3-pentafluoropropane (R-225ca), boiling point = 56C *1,3-dichloro-1,2,2,3,3 -Pentafluoropropane (R-225cb), boiling point = 52°C *1,1.3-trichloro-2,2,3,3-tetrafluoropropane (R-224c a), boiling point = 929
C *1.3.3-trichloro-1,2,2,3-tetrafluoropropane (R-224bb), boiling point = 90°C *1-chloro-1,2,2,3,3-pentafluoropropane (R-235ca), boiling point = 44°C*1,3
-dichloro-2,2,3,3-tetrafluoropropane (R-234cc), boiling point = 68°C *1-chloro-2,2,3,3-tetrafluoropropane (R-244c a), boiling point -56 °C*1,1-dichloro1.2.2-)rifluoropropane (R-24
3c c), boiling point=60℃*1,3-dichloro-2,
2-difluoropropane (R-252ca), boiling point =
66°C *1,1-dichloro-2,2-difluoropropane (R-252cb), boiling point = 79°C *dichloromethane, boiling point = 40°C *1,1,1-trichloroethane, boiling point = 74°C These hydrogens The halogenated hydrocarbons contained can be used alone or as a mixture of two or more. When used as a mixture of two or more, it is preferred over those forming an azeotropic composition.

In addition, for hydrogen-containing halogenated hydrocarbons, 1
Other organic solvents, stabilizers, etc. may be added within a range not exceeding 0%. When an organic solvent is added, effects such as improved rinsability are achieved.

When cleaning and removing various contaminants using the method of the present invention, first, the article to which the contaminant has adhered is brought into contact with terpene alcohol. Contact between the article and the terpene alcohol is not particularly limited, and can be carried out by any method such as immersing the article in the terpene alcohol or spraying the article with the terpene alcohol. The temperature of the terpene alcohol when it comes into contact with the article can be within the temperature range from room temperature to below the flash point, but in order to promote the removal of contaminants, it is preferably heated to about 50 to 80 ° C. . Further, during the immersion treatment, in order to promote dissolution and removal of contaminants, means such as applying mechanical force such as ultrasonic vibration, stirring, and brushing may be used in combination. Contact of the article with the terpene alcohol may be for a period of time necessary to remove the contaminant to the desired degree.

Next, the article that has been cleaned by contact with the terpene alcohol is brought into contact with a hydrogen-containing halogenated hydrocarbon to perform pampering. The method of contacting the article with the hydrogen-containing halogenated hydrocarbon is also not particularly limited, and includes a method of immersing the article in the hydrogen-containing halogenated hydrocarbon, a method of spraying the article with the hydrogen-containing halogenated hydrocarbon, and a method of contacting the article with the hydrogen-containing halogenated hydrocarbon. This can be carried out by a method such as cleaning with hydrogen-containing halogenated hydrocarbon vapor. In addition, to increase the rinsing effect, repeat the same rinsing method repeatedly,
A combination of different rinsing methods may be used. In particular, when the immersion method or spraying method is combined with steam cleaning, it not only enhances the rinsing effect and accelerates drying, but also allows the rinsing solution to be recycled and reused.
A significant reduction in the amount of rinsing liquid and a significant simplification of the cleaning process are achieved, resulting in articles with more consistent cleaning quality. The temperature and time during rinsing vary depending on the type of contaminant, the degree of contamination, the degree of cleaning with terpene alcohol, the rinsing method, etc., and are usually about 15 seconds to 3 minutes at room temperature to about 80°C.

The cleaning method according to the present invention is particularly effective in removing rosin wax used in soldering printed circuit boards and residues from adhesive tapes. The cleaning composition of the present invention further includes oils, waxes, greases,
It is also highly effective in cleaning and removing various other contaminants such as oil-based abrasives.

Effect of the invention According to the method of the present invention, the following effects are achieved.

(1) Since the cleaning liquid used does not contain chlorine atoms, it does not cause so-called environmental problems such as environmental pollution or destruction of the ozone layer.

(2) Hydrogen-containing halogenated hydrocarbons used as a rinsing liquid are easily decomposed in the atmosphere, so they are difficult to reach the stratosphere and have little impact on the ozone layer.

Its influence is, for example, R-1 compared to R-11:3.
23 is 1/40 or less, and R-225cb is 1/20 or less.

(3) In both the washing process and the rinsing process,
Since no water is used, the process and equipment are simplified.

That is, since there is no need for water purification treatment or wastewater treatment after use, there is no need for a large amount of equipment, land, operating costs, etc. that are required for these.

Furthermore, drying processes for adhering water such as hot air drying and high-frequency heating, which are necessary when using water, are also unnecessary.

(4) Since the hydrogen-containing halogenated hydrocarbon used in the rinsing treatment has a relatively low boiling point, it is easy to separate and remove contaminants by distillation, and it can be used repeatedly by regeneration. Therefore, the amount of rinsing liquid used is significantly reduced.

(5) For cleaning equipment that conventionally used chlorofluorinated hydrocarbons, chlorinated hydrocarbons, etc., the cleaning liquid can be replaced with terpene alcohol and the rinsing liquid can be replaced with hydrogen-containing halogenated hydrocarbons without making major equipment modifications. Just that is fine.

(6) Many hydrogen-containing halogenated hydrocarbons are nonflammable, so in conjunction with the fact that the cleaning process is carried out below the flash point of the terpene alcohol, the entire cleaning process can be carried out without the risk of ignition or explosion. be able to.

(7) Both terpene alcohols and hydrogen-containing halogenated hydrocarbons have little toxicity to living organisms and are safe.

(8) Terpene alcohols and hydrogen-containing halogenated hydrocarbons both have excellent chemical stability, and terpene alcohols have little effect on various materials such as metals, plastics, and elastomers, so these materials can be combined. It is possible to directly clean the object to be cleaned.

EXAMPLES Examples and comparative examples are shown below to further clarify the features of the present invention.

Examples 1 to 2 and Comparative Examples 1 to 2 Rosin-based flux (trademark "AGF-200J", manufactured by Asahi Chemical Research Institute) was soldered (at 260°C) to a 10 cm x 10 cm printed circuit board using an automatic soldering machine. It was used as a test piece.

Next, the test pieces were washed and rinsed using a washing liquid and a rinsing liquid under the conditions shown in Table 1 below, and the removal effect on rosin-based flux was determined.

Example Comparative Example 1 Surface cleaning Rinse (immersion) (immersion) α-Terpineol R-12360°C, 30
Seconds 20°C, 30 seconds a-chill quick-all R-225cb ultrasonic application 30°C, 130 seconds 60°C, 30 seconds steam rinse 30 seconds R-225cb 30 seconds a-terpineol a-terpineol
None 60°C, 30 seconds 60°C, 30 seconds Mixture A Mixture A Mixture A 20°C, 30 seconds 20°C, 30 seconds 30 seconds Note: Mixture A = R-141b/R-123 = 65/35w
The appearance of the specimens and the amount of ionic residue after the t% cleaning and rinsing treatments are shown in Table 2.

Appearance part 2 Table Ionic residue (, czgNac1/cJ) Example 1 Surface cleanliness 0.4 or less 2 Surface cleanliness 0.4 or less Comparative example 1 Undried 1.8 2 White residue 3.5 From the results shown in Table 2 , it is clear that the method of the present invention has an excellent removal effect on rosin-based flux.

Examples 3-4 Press machine oil (
Trademark "PG-3080" (manufactured by Nippon Craft Oil Co., Ltd.) was applied thereto to prepare a test piece.

Next, the test pieces were washed and rinsed using a cleaning liquid and a rinsing liquid under the conditions shown in Table 1, respectively, and the removal effect on machine oil was determined.

Table 3 shows the appearance of the test pieces and the amount of residual oil after washing and rinsing. The amount of residual oil was calculated by determining the weight of the test piece before and after washing.

Table 3 Appearance Residual oil content (mg/cJ) Example Comparative example 3. Undried 4. Undried Surface cleanliness 99.99 Surface cleanliness 99.99 50° 99° (Hereafter Up)

Claims (2)

[Claims] (1) A method for cleaning the surface of an article, which comprises bringing a contaminant-attached article into contact with terpene alcohol to dissolve and remove the contaminant, and then rinsing the article with a hydrogen-containing halogenated hydrocarbon. (2) The method for cleaning the surface of an article according to (1), wherein the hydrogen-containing halogenated hydrocarbon has 1 to 3 carbon atoms and a boiling point of 25 to 100°C.