The student came back to Professor Guilio Natta and produced the same catalyst in Guilio Natta’s lab. Professor Natta used this catalyst in polymerization of PP and succeeded to get amorphous PP. Natta then modified the catalyst and succeeded to get crystalline PP. Without informing Professor Ziegler, Prof. Natta filed a patent for the same. During the same time, Prof. Ziegler also successfully carried out the polymerization of PP in his lab. He also filed a patent for the same and consequently, a long legal battle started over the patents rights and who should claim to be the inventor.
It is common in modern science and technology that the growth of the general body of knowledge can lead to the same inventions in different places at about the same time, but polypropylene was an extreme case of this phenomenon, being separately invented about nine times. It was a patent attorney’s dream scenario, and litigation wasn’t resolved until 1989.
Nevertheless, in 1963 both the professors shared the Noble Prize in Chemistry for their inventions; and the catalyst system, used today with several modifications, is known as Ziegler-Natta catalyst. However, two American chemists working for Phillips Petroleum of the Netherlands, Paul Hogan and Robert Banks are now generally credited as the ‘official’ inventors of this material.
The innovations in catalyst systems and industrial processes became the basis of differentiation of several industrial process technologies. Their capability of controlling the product characteristics and process performance were the factors to consider before acquiring the manufacturing facility.
Among the major technology providers and process licensors, LeyondellBasell (with principally Spheripol technology), is a successor of Prof. Natta’s research and development, and thus justify claims to be the biggest licensor of its highly developed technology. LeyondellBasell itself is also the world’s biggest producers of polypropylene.
Spheripol process is the result of continual improvement in polypropylene technology as well as catalysts since 1960, incorporating breakthroughs in process design, through the refinement of gas-phase and bulk polymerization reactors. For the production of impact copolymers, Spheripol process is the most widely used example of hybrid process. The process is capable of selectively controlling the product characteristics, as well as providing better yields, engaging minimum energy requirements – a step towards better environment.
NATPET is producing different grades of Homopolymer, Random copolymer, and impact copolymer using the most optimized polymerization process (Spheripol) under the brand name of Teldene®.