What is remarkable about Japan’s efforts to save the ozone layer is not so much attempts by Japanese chemical companies to come up with substitutes for chlorofluorocarbons (CFC). Rather, it is the success that Japanese CFC users are having in weaning themselves off depend

CFCs have tour principal industrial uses. They serve as coolants in refrigerators and air-conditioners, as blowing agents in foams for packings, insulations and furnishings, as propellants in aerosols and as cleaning fluids for electronic products.

Developed in the US in the 1930s, CFCs quickly became popular because — in addition to being useful — they were not toxic, flammable or corrosive. Some 50 years later, long after the compounds had been applied on a massive scale, it was discovered CFCs also had a darker side. The compounds were found to be responsible for breaking up the ozone layer that protects the Earth from damage by high energy ultraviolet rays from the sun.

In Montreal in 1987, industrialised nations agreed to halve usage of CFCs by the end of the century. When the protocol was signed, Japanese companies were responsible for producing 15% of the world’s CFCs and were second only to the US as users of the chemicals. Since Montreal, the Japanese have made much progress. As ever when commercial interests are at stake, the Ministry of International Trade and Industry has taken on the leading role of finding a solution.

The ministry is supporting a five-year, ~5.6 billion (US$40.9 million) research project among Japan’s five CFC producers — Showa Denko, Daikin, DuPont-Mitsui, Asahi Glass and Central Glass — on the development of substitutes. It is also coordinating efforts by 35 major Japanese users of CFCS to work out ways of initially reducing their consumption of the chemical —through such strategies as recovery and recycling — before phasing out usage altogether.

Substitutes for some CFC5 already exist. They include the hydrochlorofluorocarbons, which do less damage to the ozone layer than their simpler chemical cousins, and hydrofluorocarbons (HFC), which are used principally as a substitute for CFCs in air-conditioners and refrigerators.

The problem is that, in addition to being more expensive, HFCS also have smaller molecules, and as a result they tend to leak out between the joints of components designed for CFC5. What this means in practical terms is that products built to use CFCs have to be redesigned for the substitute compound. Japanese car makers, led by Nissan, have been doing just this to the air-conditioners installed in their vehicles.

However, completely redesigning a product is both complex and expensive because, in addition to tightening up joint tolerances to prevent leakage, several other considerations are involved. For example, new lubricants that were compatible with HFCS have had to be developed. In addition, HFCS corrode the rubber used in hoses and other connectors on present generation air-conditioning units, so chemists have had to develop substitutes.

Nissan recently announced it had completed testing its new, environment-friendly, air-conditioners in over 100 vehicles. The success of these tests has enabled the company to bring forward its target for phasing out CFCs in its products from 1995 to 1994.

Half of all CFCS consumed in Japan are used as cleaning agents by the electronics industry. Instead of waiting for less effective, more expensive substitutes for CFCS to be developed and introduced, this industry is attempting to deal with the problem by eliminating the use of chemical cleaners altogether.

NEC, a corporation which claims to be one of Japan’s most environmentally conscious firms, in 1989 used 280 tons of CFCs to clean flux — a resinous material used to facilitate soldering —off computer printed circuit boards.

Before parts are soldered onto them, boards are usually dipped in a bath of foaming flux. The result is that, after soldering, they have to be thoroughly cleaned with CFCS to remove the unneeded flux.

In order to reduce its CFC usage, NEC developed a system that sprays flux onto boards in the form of a fine mist. The flux left over from this process settles as a powder, which can easily be mechanically removed without the need for CFC’s. A second virtue of this system is that it also reduces the amount of flux used by 80%.

Since December 1990, NEC has been marketing its system on a commercial basis. By March, the company had received 10 orders for the ~4.5 million product, and hopes to sell a further 50 units during this fiscal year. 

-U Bob Johnstone

Source : Far Eastern Economic Review, 19, sept, 1991

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