The data picked the supported catalyst in 1978. Sixteen years later, the European Commission found even Europe’s old plants running on it.
Polypropylene, the plastic in bottle caps and car bumpers, is made with a catalyst that links propylene gas into long chains. The TiCl₃ catalyst, used since the 1950s, made so little plastic per gram that plants had to wash it out of the product. The supported catalyst spreads the titanium thinly over magnesium chloride, so far more of it does useful work. For each we measured how much better per dollar it got every year, using only the patents that existed at the time.
% better per dollar each year. Readings every two years. The signal came four years before Spheripol.
In 1978 the supported catalyst was improving 1.3 times as fast as the TiCl₃ catalyst, 27% a year against 21. The gap widened to 1.9 times by 1984, and the TiCl₃ catalyst did not catch up for four decades.
Each gram of supported catalyst made several times more plastic, nearly all of it the hard, useful kind. So a plant could drop the sections that washed out catalyst and removed the soft, sticky part. Spheripol, launched in 1982, was built that way.
Our data: the supported catalyst improving faster than the TiCl₃ catalyst.
Montedison launches Spheripol, a process built around the supported catalyst.
Hercules, the first US polypropylene maker, joins Montedison in Himont to use its new process.
Rival Union Carbide and Shell run their first full-scale plant, in Seadrift, Texas.
The European Commission finds Spheripol the most licensed process, and Europe’s old plants on high-yield catalysts.
LyondellBasell’s annual report calls Spheripol the most widely used polypropylene process.
It would not have said which plant design would win, or who would license it. It would have said the polypropylene plant of the future would be built around the supported catalyst, four years before Spheripol was launched.
For a process licensor, that is the window to design a plant around the catalyst and license it. Montedison did both, and Spheripol became the most widely licensed process in the world.
The same reading works for the next call: which plastic recycling route earns the scale-up beyond Wesseling.
TIR — the Technology Improvement Rate — measures how fast a technology gets better each year, computed from global patent data. Not who is filing, or how much: how fast the route is actually moving. Historically, the fastest-improving technology always wins.
Provenance. Every patent carries a publication date, so the record can be replayed: every improvement rate on this page uses only the patents that were published at the time. Chart data: GetFocus platform exports, October 2026.
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