ＲＩＴＥ−YＵＵＫＩ LＡＢＯＲＡＴＯＲＹ
in Hitachi Chemical Co., Ltd.

ＲＩＴＥ−SHIMODATE LABORATORY
in Hitachi Chemical Techno-Plant Co., Ltd.

In the electronics parts industry, CFC substitute detergent are employed to clean printed circuit boards, etc. However, the CFC substitute detergent which has been put into practical use contains high concentrations of organic compounds which are synthesized from petroleum and has low decomposability depending on the microorganism. Printed circuit boards generate a considerable amount of soldering flux residue when they are defluxed by cleaning. The former non-CFC cleaning and waste water processing became an obstacle in reducing the use of CFCs since they used to require large scale equipment. Therefore, our research laboratory developed a new non-CFC cleaning system which reduces overall loads on the environment.

1. Development of flux: We have developed a low residue flux which is highly reliable as a soldering flux for printed circuit boards and has high decomposability depending on the microorganism, yet has a small flux residue after completing soldering.

2. Development of detergent: We have established the basic composition of a detergent after investigation of the detergent composition, cleaning capability, decomposability depending on the microorganism, effect on printed circuit boards and safety, centering around alcoholic-based detergents. After practical cleaning evaluation tests, we have completed development of the new detergent DAA-15.

3. Development of cleaning equipment: We have manufactured trial cleaning equipment to study the effect of spray cleaning, effect of ultrasonic wave and effect of eliminating liquid by centrifugal force. After analysis using the trial cleaning equipment, we have good prospects for reducing the size of cleaning equipment by about 20% by adding liquid elimination function using centrifugal force.

4. Development of detergent reclamation equipment: We have developed mainly the reverse osmosis and distillation methods for the purpose of separating detergent from flux. As a result of d evelopment, we have established reclamation and recycling technology of detergents using distillation or distillation under reduced pressure.

5. Development of waste water processing technology and water recycling equipment: We have established the fundamental specifications of a high concentration waste water treatment system by activated sludge process with membrane filtration using mainly biological processing. We have established the fundamental specifications of water recycling equipment using a reverse osmosis membrane after operation of our trial production equipment for one year.