• Clean Technology
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• v.10 no.2
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• pp.73-87
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• 2004

In most of industrial fields, cleaning is employed for removing soils on their products or parts. Halogenated cleaning agents such as CFC-113, 1,1,1-TCE(1,1,1-trichloroethane), MC(methylene chloride) and TCE (trichloroethylene) have been used as cleaning ones in most of companies in the world since their excellent performance of cleaning ability and good material compatibility. However, CFC-113 and 1,1,1-TCE which are ozone destruction substances are not used any more in the advanced countries because of the which are ozone destruction substances are not used any more in the advanced countries because of the Montreal protocol. MC and TCE are now used restrictively at small part of industrial fields in most of countries since they are known to be hazardous or carcinogenic materials. Thus, it is indispensible that the alternative cleaning agents which are environmental-friendly and safe, and show good cleaning ability should be developed or utilized for replacement of the halogenated cleaning agents. Aqueous/semi-aqueous cleaning agents are evaluated to be promising alternative ones among various alternatives in environmental and economical view point. In this study, commercially available 12 aqueous and 6 semi-aqueous cleaning agents were selected and their physical properties, cleaning abilities, rinsing abilities and recycling of contaminated rinse water were measured and analyzed. Aqueous cleaning agents with higher wetting index showed better cleaning ability compared with those with lower wetting index. However wetting index did not have any correlation with cleaning ability in semi-aqueous cleaning agents. It was observed that soil concentration in aqueous and semi-aqueous cleaning agents should be maintained below the certain concentrations which depend on types of clearing agents. More than 70% soils in contaminated rinse water by some of aqueous and semi-aqueous clearing agents could be separated by simple settling method. This means that some cleaning agents with high oil-water separation efficiency will be effiective for recycling oil-contaminated rinse water. It was found that contaminated rinse water with aqueous agents was purified easiy by ultrafiltration method with PAN membrane of 30 kDa.

• Clean Technology
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• v.9 no.1
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• pp.9-21
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• 2003

CFC-113 and 1,1,1-TCE which are ozone destruction substances are not used any more in the advanced countries because of Montreal protocol. MC and TCE are now used restrictively at small part of industrial fields in most of countries since they are known to be hazardous or carcinogenic materials. Thus, it is indispensible that the alternative cleaning agents which are environmental-friendly and safe, and show good cleaning ability should be developed or utilized for replacement of the halogenated cleaning agents. Aqueous cleaning agents are evaluated to be promising alternative ones among various alternatives in environmental and economical view point. This study has been carried out as a part of development program of aqueous cleaning agent. First of all, several types of surfactants which are the most important component in aqueous cleaning agents were chosen, and the physical properties, foaming ability, cleaning ability and oil-water separation efficiency of their aqueous solutions were measured and compared for selection of proper type of surfactant in aqueous cleaning agents.

• Clean Technology
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• v.12 no.1
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• pp.1-9
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• 2006

Aqueous cleaning agents which are considered to be environmental-friendly and promising alternative ones among various industrial cleaning agents were evaluated in this words. In order to formulate aqueous cleaning agents, primary alcohol ethoxylates with 3, 5 and 7 moles of ethylene oxides among nonionic surfactants were selected as main surfactants. And anionic surfactants and alcohols were chosen as their cosurfactants. Builders such as NaOH, KOH, $Na_2CO_3$ and $NaHCO_3$ were also evaluated as additives for improvement of cleaning efficiency of aqueous cleaning agents. The experimental results of cleaning ability tests show that introduction of anionic surfactant TLS as cosurfactant in alcohol ethoxylate-based aqueous solution gives the best cleaning efficiency for removing mixed soil of cutting oil and grease. NaOH and $Na_2CO_3$ are also shown to play an important role for improvement of cleaning efficiency in a aqueous cleaning agent.

• Clean Technology
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• v.3 no.2
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• pp.36-46
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• 1997

CFC and organic chlorine solvents has been used in the fine machinery and electronics industries for a long time since they have various excellent properties as cleaning agents. However, it is inevitable that alternative cleaning agents should be used since CFC and organic chlorine solvents were identified as ozone-depleting chemicals. There are various alternative cleaning agents. Among them, aqueous/semi-aqueous cleaning agents are environmentally friendly and promising in the long term. And their use and developement are on the increase in advanced countries, but few in our countries. In this paper, the charactistics and major components aqueous/semi-aqueous cleaning agents are analyzed and compared. And various cleaning equipments for aqueous/semi-aqueous cleaning agents such as immersion cleaner, ultronsonic cleaners, power spray cleaner, and vibration or rotational cleaners are compared and evaluated. Finally, important consideration points for selction of a cleaning system are analyzed and suggested in this paper.

• Clean Technology
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• v.12 no.4
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• pp.250-258
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• 2006

CFC compounds such as CFC-113 and 1,1,1-TCE, etc. have been used in various industries due to their excellent chemical stability, thermodynamic characteristics, non-inflammability and anti-corrosiveness. However, in oder to protect the earth environment, "the Montreal Protocol on substances that deplete the ozone layer" was adopted in 1989 for prevention of production and utilization of these CFC compounds and alternative cleaning agent have been required in the industry. The objective of this study is to develop non-aqueous cleaning agents that do not require major change of cleaning system, have excellent cleaning efficiency, are favorable to the environment, are harmless to the human body, and are not generated corrosive materials. In this work, non-aqueous cleaning agents have been formulated with glycol ether series and paraffinic hydrocarbon series with siloxane, and their physical properties and cleaning efficiencies were analyzed and compared with those of regulated materials. As a result of physical properties measurement of the formulated cleaning agents, it is expected that they may have good penetration ability into contaminated materials due to their properties with low density and low surface tension. Measurement of flash point and vapor pressure of the cleaning agents will be helpful for evaluation of their safety and working environment. The experimental results of cleaning flux, solder and grease by the formulated cleaning agents show that their cleaning abilities of soils were good and that there were no residues on the substance after cleaning. Therefore, alternative cleaning agents which have equivalent cleaning ability to regulating materials, good penetration ability and low hazard to human body, have been developed in this work.

• Clean Technology
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• v.16 no.2
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• pp.103-116
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• 2010

It has been reported that the LCD panel market in the FPD industry is become growing and its panel size and production capacity are increasing, and its manufacturing technique is improved every year. FPD manufacturing process requires high cleanliness in its overall process. Especially, FPD cleaning process which accounts for 30~40% of total manufacturing process is very important in its technological and productivity aspects. It is difficult to remove residual liquid-crystal in the fine gap after liquid-crystal injection process in the cell. In this study, aqueous cleaning agents with excellent cleaning, rinsing, and penetrating abilities, but minimum ion content for LCD panel were formulated through mixing glycol ether-type and glycol dimethyl ether-type solvents and nonionic surfactants which are widely used as raw materials for alternative cleaning agents because of environmental regulation at home and abroad. And the formulated cleaning agents were applied to clean FPD liquid crystal after its injection in the cell. Physical properties, cleaning efficiencies, and rinsabilities of the formulated cleaning agents with different combination ratios of solvents, surfactants and additives were measured. As experimental results, the formulated cleaning agents showed higher wetting indices and cloud point than the traditional commercial cleaning agent. And it was found that cleaning efficiencies of the formulated cleaning agents were influenced by the structure of main solvents in them and the types of liquid crystal as soil for cleaning. The best cleaning agents among the formulated cleaning agents showed similar cleaning efficiencies and better rinsabilities compared to the conventional cleaning agent.

• Applied Chemistry for Engineering
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• v.16 no.4
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• pp.533-541
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• 2005

Non-aqueous cleaning agents were formulated with 2,2,2-trifluoroethanol (TFEA) and hydrofluoroether (HFE), and their physical properties and cleaning abilities were examined. TFEA-based aqueous cleaning agents were also formulated with nonionic surfactants, hydrotropes and builders, and their cleaning abilities were compared. Possibilities of these cleaning agents as substitutes for CFC-113 and 1,1,1-TCE were finally evaluated. In this work, fluxes, cutting oils, greases, and fluoric oils were selected as model contaminants for cleaning experiments. These contaminants have different properties of water-solubility or hydrophilicity, and fat-solubility or lypophilicity. Cleaning abilities of TFEA-based cleaning agents were analyzed and compared through the measurement of contaminant weight changes as a function of cleaning time, and their possibilities as alternative cleaning agents were evaluated. As a result, it was shown that TFEA and HFE-based non-aqueous cleaning agents have quite a good cleaning power for fluxes and fluorine soils but low one for greases. And TFEA-based agueous cleaning agents which consisted of nonionic surfactants, hydrotrope, and builders were very effective for cleaning fluxes and greases under certain formulation conditions. Thus, it was revealed that the TFEA-based cleaning agents were very effective for cleaning specific contaminants and can be used as substitutes for CFC-113 and 1,1,1-TCE in some industrial applications.

• Clean Technology
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• v.10 no.2
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• pp.61-72
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• 2004

In this study, aqueous/semi-aqueous cleaning agents which consist of organic solvent, surfactant, cosurfactant, and water were developed by changing formulation parameters such as organic solvent type and contents, surfactant type and contents, and cosurfactant/surfactant(A/S) ratio, etc.. And physical properties and flux removal of the formulated cleaning agents have been evaluated. Also, the performance of oil-water separation from the rinse water contaminated during the cleaning process was evaluated for its recycling. The formulated cleaning agents in this work expected to have good penetration because of their low viscosity and low surface tension values of 30.2~32.5 dyne/cm. The flux removal with the terpene type cleaning agent was higher than that with hydrocarbon type cleaning agent and two commercial products (CPA(commercial product A), CPB(commercial product B)). And the performance of oil-water separation by gravity settling from the rinse water contaminated with formulated cleaning agent and soils was shown to be very good. The cleaning agents developed in this work were applied to surface mounting technology(SMT) cleaning process for manufacturing electronic parts at L electronic company. As a result, the newly developed cleaning agents showed two times better cleaning speed for removal of solder cream than the conventional ond containing ethanol and IPA(isopropyl alcohol). In addition, malodor and VOC problems generated by the previous organic cleaning agents have been solved in the manufacturing field through introduction of the non-volatile and environmental-friendly cleaning agents to the field.

• Clean Technology
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• v.19 no.3
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• pp.219-225
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• 2013

Environment-friendly and surfactant-free aqueous cleaning agents have been developed in order to solve various problems generated by surfactants in the aqueous cleaning agents. Aqueous surfactant-free cleaning agents, S-1 and S-2 have been formulated with water-soluble solvents such as propylene glycol and propylene glycol ether on their main components and with some additives. These solvents were chosen because of their good solubility in water and excellent solubility of fluxes which are major contaminants of printed circuit board in the electronic industry. Physical properties of the formulated and the imported cleaning agents were measured to predict their cleaning performance, and their cleaning abilities of flux and solder contaminants were evaluated under the various ultrasonic frequencies by a gravimetric method. The measurement results show that the physical properties of cleaning agent V are generally similar with those of formulated cleaning agents S-1 and S-2. Both the cleaning agent V and the formulated cleaning agents S-1 and S-2 showed similar trends that their pH decrease in the beginning and then increases later on with the increase of their dilution in water. It is considered that the wetting indices of the cleaning agents calculated with experimental values do not not have any influence on their cleaning ability. In ultrasonic cleaning tests under three ultrasonic frequencies of 28, 45, and 100 kHz, their best performances of cleaning solder and flux were obtained at 45 kHz and 28 kHz, respectively, and the cleaning performance of the formulated cleaning agents S-1 and S-2 was better than that of the cleaning agent V. However, in the case of the recommended diluted concentration of 25 wt% cleaning solution, the cleaning performance of the cleaner V for solder and flux was better in the initial stage of cleaning compared to the formulated cleaners. And it may be concluded that the formulated cleaning agents S-1 and S-2 can be applied to cleaning of solder and flux in the industry, based on the experimental results in this study.

• Clean Technology
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• v.18 no.3
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• pp.287-294
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• 2012

In this study, performances of two cleaning methods were analyzed and a cleaning system was designed to develop a cleaning process of electronic components to remanufacture old laser copy machine. First, plasma cleaning as a dry cleaning method was executed to test cleaning ability. In cleaning of printed circuit board (PCB) by plasma, some damages were found near the metal parts, and considering the productivity, this method was not adequate for the cleaning of electronic components. With 4 different cleaning agents, ultrasonic cleaning tests were executed to select an optimal cleaning agent, aqueous agents showed superior cleaning performance compared to semi-aqueous and non-aqueous agents. Cleaning with aqueous cleaning agent A and 28 kHz ultrasonic frequency can be completed in 30 sec to 1 min. Finally, an ultrasonic cleaning system was constructed based on the pre-test results. Optimal cleaning conditions of 40 kHz and $50^{\circ}C$ were found in the field test. The productivity and economic efficiency in remanufacturing of laser copy machine are expected to increase by adapting developed ultrasonic cleaning system.