Vinyl, what has changed?

[X-PertPool]

I service a pool that has it's original liner. The pool was installed in 1971, a year before Hurricane Agnes. The liner has a bunch of patches (especially at the water line) but it has yet to show any signs of becoming brittle. The vinyl is a teal/green color with no print. Liners today have about a 10-15 year lifespan until they get replaced and upon replacement they are usually quite brittle especially on the floor of the pool. So what has changed over the years? I spoke to the place that I get my liners from and they basically gave me a blanket answer of "they removed the harmful chemicals that allowed vinyl to last longer" and said it is similar to how lead paint was found to be poisonous but did make for a very good paint

So does anyone know?

 

[JasonLion]

There are various additives used as "plasticizers", some of which are no longer in use because of environmental considerations. However, I suspect that what makes the difference in this case is that they used an especially heavy layer of UV blocker.

 

[X-PertPool]

Seems like a typical example of "they don't make it like they used to"