Honest??

It seems it didn't have anything to do with patent expiration. Just another urban legend??

Dupont were by no means the only producer of R12 and not the inventor. Most patents ran out in 50s. Freon became a generic name, but much of the R12 used in cars was likely made by others, such as Allied Chemicals.

The process to restrict CFCs started in early 70s in USA and accelerated after '85 due to discovery of ozone holes by the British. Dupont at one stage did their own investigation and confirmed that CFCs did in fact affect the ozone layer.

DuPont did conduct a PR campaign to defend CFCs against environmental groups who wished to curtail their use. At first because the scientific data was meagre, but later they claimed that time was needed to develop alternatives (which was true).

Once the replacement products had been tested and proven acceptable, Dupont then changed their tune and became pro-active in supporting the phase-out of CFCs. They no doubt did see a competitive advantage in that they now had replacement products and competitors would have to scramble to catch up.

Or that's the way I recall it (I was involved in a small way)

can you explain why R134, 40x,a/b/c etc 410 etc are now being banned... also about when profits fail

The replacements for R12 were the best available at the time. Certainly helped with the ozone problem. But they are still greenhouse gases and much worse than CO2. Somehow I doubt the producers of current refrigerants are pushing for the changes nor would the refrigeration/air conditioning industry.

The world has changed since R12 was first banned and now these replacement refrigerants are now getting the attention of the environmentalists. Just have to look at what has happened to the new diesels to see how the world has changed since the 80s.

Not everything that is being done for the environment seems to make sense and it can be frustrating when in affects us directly. But overall I am happy we are doing something.

Here is a link from Australia that covers some aspects of the changes from a guy that works in the field.

bad link

Thanks - Fixed.