PART II
THE INVENTIONS OF GIULIO NATTA: 4000 PATENTS, CLASSIFIED INTO 333 FAMILIES

Introduction

In parallel with his activity as a scientist, from his first years of academic life onwards, Giulio Natta built up a significant activity as an inventor, which led to the filing of a considerable number of industrial patents, many of which acquired important industrial applications.

The first Italian patent for G. Natta, titled "Process for the synthetic preparation of liquid hydrocarbons", was filed on 12 April 1927 and subsequently granted with the number 257,990. The last, titled " Process for the preparation of terpolymers of ethylene, propylene and 1,3-butadiene", was filed on 11 December 1969 and granted on 2 November 1970 with the number 879,026.

We can divide the patents of Giulio Natta into:

a) a) patents filed in Italy, for the most part the result of collaborations with companies and national Bodies, which were practically all filed (extended) abroad (298 families);
b) b) patents resulting from collaboration with the company Montecatini, each consisting of the merging of two or three Italian patents, filed only abroad - right up to 1987 - (along with any modifications/integrations) (29 families);
c) c) patents arising from work done with the Swiss company Lonza A.G. (6 families).

Each of the "families" includes, for groups a) and c) the principal patent and any corresponding patents filed in other countries and, for group b) a single "Montecatini case" (see. "Montecatini List"), irrespective of the fact that for any given "case" more than one patent may have been filed and granted any given country, and that the patents granted in the various countries may or may not correspond to one other.
It should be noted that several "Montecatini cases" were the object of a high number of filings abroad (up to 100 in more than 70 countries, see for example case no. U59+U63+UT76 in the Montecatini List) - and were sometimes subject to division into more than one patent for a single country - subsequently granted with a number of its own, not necessarily on the same date: for example, for Montecatini case U59+U63 five patents were filed in Germany, 8 in Canada and, between 1955 and 1983, 15 in the USA, 7 of which - clearing differing one from the other - granted between 1963 and 1971.

The overall number of patents bearing the name of Giulio Natta, granted in Italy and abroad, is a little under 4000.

The "inventions" described in Natta's patents always concerned subjects of great practical interest for the periods from which they date: some of the themes they dealt with are still topical today.
A first important group, developed from 1927 to 1937 within the context of the relationship with Montecatini, concerned the synthesis (at high pressure: up to 400 atm) of methyl alcohol and higher alcohols and the preparation of the gas mixture (carbon monoxide and hydrogen) necessary for this synthesis. Wide research into the same subjects was then being conducted in Germany. The patents on the synthesis of methanol and the preparation of new catalysts led to the construction of industrial plants in Italy and abroad. The higher alcohols have come back into the news once more due to their use in the sector of automobile fuels.
Due to the renown achieved internationally by Natta in these fields he was asked, in the 1940s and 1950s, to write specific monographies which appeared in some of the most distinguished American and German publications.
The patents for producing the mixtures of carbon monoxide and hydrogen needed for the synthesis of alcohols were based on the gasification of coal and lignite - technologies which were also being researched in Germany - which subsequently found significant applications in Germany during the Second World War and are still being used today in South Africa, the USA, China and other industrialized countries.
The experimental gas generator on which Natta conducted these researches was installed in a courtyard at the Institute of Industrial Chemistry of the Polytechnic of Milan, where it continued to be on show up to the 1960s.
In times of national self-sufficiency, in the context of relationships with national industries (O. De Nora, BPD, Baslini), Natta dedicated himself to obtaining chemical compounds from vegetable raw materials, inventing processes that were subsequently covered by patents. One could maintain that, in this field too, Natta was before his time, given the recent rekindling of interest in this subject.
The group of patents on the synthesis of methanol was followed by that on the preparation of formaldehyde from methanol.
During the Second World War it became imperative, in Italy as elsewhere, to be able to produce synthetic rubber. Italy therefore set up the Institute for the Study of Synthetic Rubber, and Natta was called upon to work with it. At that time, as at present, the most important synthetic rubber was one based on butadiene-styrene copolymers. Natta set to work on the preparation of styrene and, in particular, on obtaining butadiene with a level of purity sufficiently high for its copolymerizaton with styrene. For this purpose he invented a brilliant and original process ("fractionated absorption") for the separation of butene-1 from butadiene, a process which was patented and immediately acquired an industrial application.
In the 1940s an interesting synthesis was discovered in Germany (hydroformylation, or "oxo-synthesis"), which made it possible, operating at high pressure, to add carbon monoxide and hydrogen onto olefins to obtain aldehydes, which could then be transformed into alcohols. Given his experiments on the chemistry of carbon monoxide and hydrogen and on synthesis at high pressure, Natta was quick to tackle the issue, both on the scientific and on the applicative front, with the subsequent filing of patents and the drafting of a monography which appeared in an eminent German publication. In this field - in the context of a relationship with a Swiss company (Lonza A.G.) - Natta extended his research to acetylenic compounds, and the results were soon covered by patents and put to application in the construction of a small industrial plant, operating at 300 atm, built entirely of stainless steel in the workshop of the Institute of Industrial Chemistry at the Polytechnic of Milan, and then installed in Switzerland.
At the same time, Natta was considering the use of propylene, a simple olefin, which was produced in large quantities as a coproduct along with ethylene (in particular at the first major European petrochemical plant set up in Ferrara in 1951) but which, at the time, had limited applications.
Alerted by the results achieved by Karl Ziegler in the dimerization of alpha-olefins in the presence of organometallic compounds of aluminium, Natta decided to use the catalyst discovered by Ziegler for the polymerization of ethylene at low pressure, also in the polymerization of propylene. That is how, thanks also to his practical ability in structural chemistry, on 11 March 1954, Natta discovered isotactic polypropylene. But Ziegler's catalyst gave somewhat low percentages of isotactic polypropylene: it was necessary to discover more "stereospecific" catalysts. Thus began the intense and frenzied activity of research which brought the greatest fame to Giulio Natta, culminating in the awarding of the Nobel Prize in Chemistry in 1963.
The research which followed upon the discovery of isotactic polypropylene and the new type of polymerization (stereospecific polymerization) was carried on at the Institute of Industrial Chemistry of the Polytechnic under the guidance of Natta and with substantial contributions from Montecatini, including in terms of highly qualified researchers, up until 1970, with the discovery of over 130 types of new polymers and the catalysts necessary for their synthesis. The results relating to these discoveries were described and laid claim to in 3890 patents granted in Italy and abroad.
Some of the new polymers discovered by Natta have found significant applications. After the construction - in Ferrara in 1957 - of the first small industrial plant, the various typologies of polypropylene (and their associated new catalysts and productive processes designed and developed to a great extent in the Giulio Natta Research Centre in Ferrara) have continued to find various applications, until today, on a global scale, they occupy third place in terms of economic value of all chemical products bearing a specific name (e.g. polyethylene, polyethylene teraphthalate - PET, ammonia, etc.).
Rubbers based on ethylene-propylene copolymers (first plant set up in Ferrara in 1958) today occupy third position among synthetic rubbers, in terms of economic value, after the traditional styrene-butadiene rubbers and 1,4-cis polybutadiene, which was also discovered by Natta.

The 333 families of patents - List and reproduction

The list does not include every one of the over 3950 patents bearing the name of Giulio Natta, but only the 333 families indicated above.

For each family the list includes:
- title of the patent/family;
- names of the inventors;
- date when the priority patent, Italian or foreign, was filed (in chronological order);
- number of the patent granted ;
- number of patents filed abroad, where available;
- patent holder;
- indication of any Montecatini/Montecatin-Edison cases (the name of the company was Montecatini up to 1965, Montecatini-Edison from 1966 to 1969 and Montedison from 1970);
- notes, with an indication of any corresponding patents or patents representing a single family;
- indication of any review in Chemical Abstract.

The collection contains the Italian priority patents (or in some cases a corresponding patent granted abroad) and a single patent for each family of patents filed abroad, generally the patent with the earliest date of filing.

The patents are numbered from 1 to 333 in chronological order according to the date of filing and are viewable on display unit.

The Montecatini/Montecatini-Edison List

The list, consisting of 104 pages, includes 297 "cases" (families). For each case, indicated by a letter (A, D, F, M, O, U, or Z) and a number the following information is given (occasionally with some inaccuracies or errors which have been corrected by hand):

- title;
- names of the inventors;
- countries in which the patents were filed;

and for the individual patents:

- number and date of filing;
- number and date of award;
- date of abandonment or expiry date.

Reviews in Chemical Abstract

In the 118 pages reproduced from Chemical Abstract, 245 patents bearing the name of Giulio Natta are reviewed. For each patent, together with a summary in English, there can be found the number and title, the names of the inventors and of the holder, the date of priority and of granting and other bibliographical information concerning the family to which the patent belonged.
For the patents held by Montecatini/Montecatini-Edison the name of the corresponding "case" is written by hand.
It should be noted that occasionally for a given Italian priority patent more than one corresponding patent granted abroad is reviewed.

Gli avvisi di concessione all’estero

For the most part the Montecatini/Montecatini-Edison "cases" were the object of patents filed and granted abroad. For each country the company set up paperwork which generally concluded with the granting of the patent, of which notice was sent to a number recipients, among them Professor Natta.
By way of example the "Patent Award Notices" in 14 countries for case no. U63/A are given.
Each notice contains, in particular, an indication of the "case" and the holder, the names of the inventors, the title in the language of the country, the filing date and number , the date and issue number and the patent duration.

The granting of the patent for polypropylene in the USA

Stereoregular polypropylene (later named "isotactic") was discovered on 11 March 1954.

The first patent, titled "High molecular weight propylene polymers and process for their preparation" was filed in Italy on 8 June 1954 and granted on 17 November 1955 with the number 535,712 (Montecatini case U59). This patent was followed by the patent titled "Production of high linear alpha olefin polymers with regular structure", filed in Italy on 27 July 1954 and granted on 28 December 1955 with the number 537,425 (Montecatini case U63).
The two patents were then merged into one family (Montecatini case U59+U63) which led to the filing abroad of 31 different patent applications, each with its own title: in West Germany, between 1955 and 1971, 5 applications were filed (5 patents were granted between 1961 and 1973), in Canada, between 1960 and 1963, 7 applications (7 patents granted between 1970 and 1977) and in the USA, between 1955 and 1983, 15 applications (at least 7 patents granted between 1963 and 1973) (see Montecatini List).
Each of these applications was examined by the competent foreign offices. The granting of the patents in the USA was a particularly laborious undertaking.
It was considered of interest to collect, by way of an example, the documentation concerning the granting of US patent application no. 701,332 filed on 9 December 1957, which led to the granting, on 26 November 1963, of US patent no. 3,112,300 titled "Isotactic Polypropylene".
This rather bulky documentation (even though it is much less voluminous than that concerning US application no. 514.099 filed on 8 June 1955, and whose patent was granted only on 6 February 1973 with the number 3,715,344) comprises some one thousand pages, and includes the correspondence between Giulio Natta, Piero Giustiniani, who was CEO of Montecatini at that time, the patents office of Montecatini, and the law firm representing Montecatini in the USA, various oppositions and interferences, affidavits, statements, motions, oral arguments, depositions with US courts, documents from the US Patent Office and more besides.

This material, in chronological order for the years from 1955 to 1963, has been computerized in its entirety as it stands, without further comment, together with US patent no. 3,112,300 Isotactic Polypropylene, filed on 9.12.1957 and granted on 26.11.1963.