THE INVENTIONS OF GIULIO NATTA:
4000 PATENTS, CLASSIFIED INTO 333 FAMILIES
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
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) 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
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
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
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 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):
- 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
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 allestero
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
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.
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.