JPH0649495A - Detergent - Google Patents

Abstract

PURPOSE:To provide a detergent containing the oil-in-water type emulsion of methyl tert-butyl ether, exhibiting the same detergency as those of chlorofluorocarbons, low in toxicity, not liable to decompose the ozone layer, excellent in safety and stability, and useful for printed circuit boards, etc. CONSTITUTION:The detergent contains an oil-in-water type emulsion containing (A) methyl tert-butyl ether preferably in an amount of 10-25wt.%, and preferably further (B) a surfactant such as a monoolein-ethylene oxide (20) adduct sorbitan preferably in an amount of 10wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning agent, and more particularly to a cleaning agent for printed circuit boards, electronic parts and precision machine parts.

[0002]

2. Description of the Related Art Conventionally, chlorofluorocarbon (hereinafter referred to as "CFC") has been used as a cleaning agent for printed circuit boards, electronic parts and precision machine parts.
In particular, ethane-based trichlorotrifluoroethane (hereinafter referred to as "CFC-113", which has an appropriate detergency, excellent incombustibility, low toxicity, stability and electrical insulation, and low boiling point, surface tension and latent heat of vaporization) ) Has been used a lot.

However, CFC-113 has extremely high stability, and most of it released on the surface of the earth stays in the troposphere as it is without being decomposed, and when it gradually reaches the stratosphere, it is exposed to the strong ultraviolet rays from the sun. Decomposes to release chlorine atoms (Cl).

The released chlorine atom (Cl) reacts with ozone molecules in the stratosphere to decompose the ozone molecules and convert them into oxygen molecules.

Therefore, an ozone hole is formed in the ozone layer in the stratosphere, and the sun is irradiated with excessive ultraviolet rays on the ground surface. As a result, there is a concern that skin cancer may increase or biological systems may change. It has been adopted in each country.

[0006] Therefore, for example, a substitute containing terpene or the like as a main ingredient and having no fear of depleting the ozone layer in the stratosphere is commercially available. However, it has a strong flammability and is deficient in disaster prevention.
There is a problem that it is difficult to obtain a sufficient cleaning effect similar to that of CFC-113.

[0007]

The problem to be solved by the present invention is that a substitute for the conventional cleaning agent composed of CFC-113 is deficient in disaster prevention or does not have a sufficient cleaning effect. That is the point.

[0008]

The cleaning agent of the present invention comprises:
An object of the present invention is to provide a cleaning agent having a composition containing an oil-in-water emulsion (emulsion) of methyl tert-butyl ether, and further having a composition containing a surfactant in the above composition, which is extremely effective as a substitute for CFC-113. To achieve.

The content of methyl tertiary butyl ether (MTBE) in the detergent of the present invention is about 10-40% (preferably 10-25%). When the content is 10% or less, the cleaning effect is not sufficient because the amount of methyl tert-butyl ether (MTBE) is small, and when it exceeds 40%, the viscosity becomes high and the fluidity is lowered, so that the sufficient cleaning effect cannot be obtained. Is.

As the surfactant used in the present invention,
For example, polyhydric alcohol type and polyethylene glycol type nonionic surfactants are preferable, and the hydrophilic-hydrophobic balance (HLB value) may be adjusted to about 9.0.

The detergent of the present invention can be produced, for example, by using the solubilization inversion method used when producing an ordinary emulsion.

The detergent of the present invention has a high dissolution rate and a large amount of methyl tertiary butyl ether (MT).
BE) can exert a sufficient cleaning effect by acting as a solvent, and since it is an oil-water emulsion in particular, it has low flammability, extremely low toxicity, and excellent safety. .

Further, when a surfactant is used as the solubilizing agent, water-soluble stains are easily dissolved by the surface energy reducing action of the surfactant, so that a cleaning effect on the water-soluble stain is also exerted. Is something that can be done.

Furthermore, methyl tert-butyl ether (MTB
E) is volatile, but since it decomposes rapidly in the atmosphere, it does not act on the ozone layer in the stratosphere like CFC-113, and there is no fear of environmental damage.

Next, FIG. 1 shows the results of cleaning evaluation with the cleaning agent of the present invention.

The evaluation was performed by measuring the contact angle before and after cleaning on the surface of the solder flux coated on the substrate by the droplet method and using the difference (Δθ).

The measuring method is as follows.

That is, as shown in FIG. 2, the rotary disk 1 is fixed to the upper end and the rotary shaft 3 whose lower end is connected to the rotary shaft of the motor 2 is located at the center of the bottom of the container body 4 whose upper surface is open. On the rotating disk 1 of the cleaning device which is penetratingly supported in a watertight state via a silicon seal 5, a wiring board 6 in which copper is etched on the surface of a Bakelite substrate having a flat rectangular shape of about 2 × 5 cm 2 (Sumitomo Bakelite, for example) Syringe 7 placed on the substrate 6 and placed on the substrate 6 and rotated.
Then, 0.5 ml of a flux (trade name "SOLDERITE F-230V" manufactured by Tamura Seisakusho Co., Ltd.) using isopropyl alcohol as a solvent was dropped and uniformly attached, and the substrate 6 was dried using a vacuum desiccator, and the flux-attached surface Was measured by the droplet method.

Next, as shown in the three-phase diagram of FIG.
10% by weight of a surfactant [monooleic acid ethylene oxide condensate (20) sorbitan (trade name "TO-10" manufactured by Nikko Chemicals) and sorbitan monooleate (trade name "SO-10" manufactured by Nikko Chemicals) )] Methyl tertiary butyl ether (MTBE) [Tokyo Kasei Kogyo Co., Ltd.] adjusted in the range of 0 to 40% by weight, and the substrate 6 is dipped in the cleaning solution of the present invention comprising various oil-in-water emulsions. Ultrasonic vibration was applied for 10 minutes, this was rinsed with 30 ml of pure water and then dried using a vacuum desiccator, and the contact angle of the surface was measured by the droplet method.

The measurement of the contact angle by the above-mentioned liquid drop method uses a microsyringe on the surface of the substrate 6 to make one drop of 6 μl.
One drop was measured and the average value was used as the contact angle value.

The cleaning agent used was adjusted by an inversion emulsification method using an emulsion adjusting device, an ultrasonic crusher (Kinematica) and a homogenizer.

According to FIG. 1, when the content of methyl tert-butyl ether (MTBE) exceeds 6% (molar fraction) (preferably 10 to 25% (molar fraction)), contact before and after washing is performed. It can be confirmed that the angle difference (Δθ) is 10 ° or more and a large cleaning effect is obtained, and particularly, the content of methyl tert-butyl ether (MTBE) is 20% (molar fraction).
Then, the difference (Δθ) between the contact angles before and after cleaning obtained by measuring CFC-113 by the above-described measuring method.
It showed a value almost equal to or higher than 35 °, demonstrating sufficient substitution.

In FIG. 1, when the content of methyl tert-butyl ether (MTBE) exceeds 20% (molar fraction), it is confirmed that the difference in contact angle (Δθ) before and after washing tends to decrease. It is considered that this is because the viscosity of the emulsion gradually increases as the content of methyl tert-butyl ether (MTBE) increases, so that the fluidity of the cleaning agent on the surface of the substrate 6 deteriorates. To be

Further, a detergent containing a phosphate ion or anionic surfactant which is commercially available as a substitute for CFC-113 [trade name "Placlean HN" and "Placlean NCS" manufactured by Nikka Seiko Co., Ltd. ], The contact angle difference (Δθ) before and after cleaning was obtained using the above-mentioned measurement method, but the contact angle difference (Δθ) could not be obtained, and the substrate surface after cleaning was hardly washed. It was visually confirmed that the flux was unevenly attached. Therefore, it cannot be said that these cleaning agents have a function as a substitute for CFC-113.

[0025]

EXAMPLE Methyl tert-butyl ether (MTBE) 20
% By weight, surfactants (condensation product of ethylene oxide monooleate (20) sorbitan, sorbitan monooleate) 1
0% by weight and 70% by weight of water were mixed, treated with an ultrasonic crusher, and then homogenized at 1300 rpm.
The product was obtained by emulsifying by rotating for 10 minutes.

[0026]

The cleaning agent of the present invention having the above structure is CF
Methyl tert-butyl ether (MTBE), which has a sufficient detergency equal to or higher than that of C-113, decomposes rapidly in the atmosphere and acts on the ozone layer in the stratosphere like CFC-113. It is possible to use it as a substitute for a cleaning agent composed of "Freon" such as CFC-113 without any fear of environmental damage.

Since it is an oil-in-water type emulsion, it has low flammability, extremely low toxicity, and is excellent in safety.

Further, when a surfactant is used as the solubilizing agent, the surface energy reducing action of the surfactant easily dissolves the water-soluble stains, so that a cleaning effect for the water-soluble stains can be exerted. It is possible.

[Brief description of drawings]

FIG. 1 shows the difference (Δθ) between the content (molar fraction) of methyl tert-butyl ether (MTBE) and the contact angle on the surface of the solder flux before and after cleaning in an example of the cleaning agent of the present invention. Relationship diagram.

FIG. 2 is a schematic view of a measuring device for measuring a contact angle on a solder flux surface.

FIG. 3 is a three-phase diagram of methyl tertiary butyl ether (MTBE), a surfactant and water.

[Explanation of symbols]

 1 rotating disk 2 motor 3 rotating shaft 4 container 5 silicon seal 6 substrate 7 syringe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display part // (C11D 10/02 7:26)

Claims (2)

[Claims] 1. A detergent comprising an oil-in-water emulsion of methyl tert-butyl ether. 2. The cleaning agent according to claim 1, which contains a surfactant.