`Delrin (polyformaldehyde) toilet valve failures and exploding toilets`

I don't think I told you the problem about polyformaldehyde. DuPont in 1958 came out with this wonderful material, easily injection-moldable polymer. It's called polyformaldehyde — if you know formaldehyde, what's CH2O? It's one of the most basic types of chemical compounds. And they learned to polymerize it. Ten ksi strength, which for plastic is really good. Easy to injection mold. They said this is the plumbing material of the future, and they tested it in over 200 different solvents. They published this paper in 1958 and they gave the trade name of Delrin.