INNOVATIONS: PRESENT&FUTURE
The New Frontiers of Metal Pre-Treatment: The Organic Compounds of Phosphorus Carlo De Alessandri, Tommaso Giovenzana, and Carlo Guidetti Chemtec Srl, Corbetta (Milan, Italy)
c.guidetti@chemtec.it
Chemtec has developed PRONORTEC, a new technology based on organic phosphorus compounds for pre-treating metals prior to coating. It meets all environmental requirements and, at the same time, it guarantees the same adhesion performance of microcrystalline phosphating. This product is highly revolutionary also for its ease of application, since rinsing is only necessary for the cataphoresis process, whereas it can be avoided in any other case.
The use of processes based on technologies using such thick layers
Main features
that they fall within the definition of nanotechnology in the field of
The PRONORTEC process is based on the use of organic
industrial metal preparation to coating goes back to more than a
phosphorus compounds. This material is not only widely
decade ago. In these last ten years, however, the market of metal
present in the Earth’s crust as a component of minerals
pre-treatment chemicals has greatly changed. On the one hand,
such as apatite, but it is also one of the essential elements
the European legislators have fortunately issued regulations that
at the biological level. Phosphorus is important for bone
increasingly limit the use of heavy metals such as chrome, nickel, and
and tooth health, it is a part of cell membranes in the
zinc in order to reduce the environmental impact of processes.
form of phospholipids, and it plays an essential role in the
On the other hand, the market has also started asking for new
transformation of food into energy. It is also a constituent
techniques that are simpler to manage and more efficient, but also
of nucleic acids (DNA and RNA), some proteins, and some
reduce energy consumption and the disposal costs of the toxic-harmful
sugars, and it enables the functioning of some B vitamins.
waste typical of microcrystalline phosphating operations.
In the last few years, the scientific world has paid
In this framework, some European pre-treatment chemical
much attention to the development and study of the
manufacturers have carried out major research and development
organophosphorus compounds, whose binding characteristics
activities in order to develop new processes and meet the new
for organometallic compounds have allowed the development
legislative and market needs. We can divide the newly launched
of important catalysts.
nanotechnology processes into three categories:
These specific characteristics have prompted the Chemtec
- processes based on metals with a low environmental impact, such as
laboratory’s team of researchers to test some organic
titanium and zirconium; - hybrid organic-inorganic processes wherein various organic silicon
phosphorus compounds as a metal pre-treatment solution: this is a pioneering project, since it does not appear that there
compounds (silanes) are used in combination with some of the metals
exists a pre-coating metal treatment process based on these
mentioned in point 1;
compounds, to date. Our researchers noted that the reactivity
- organic polymer-based processes, including those based on vinyl polymers and one-stage cold systems.
of these compounds with metals (ferrous and non-ferrous) is very high: after a few seconds of contact with a highly diluted
All these processes guarantee a real reduction of the environmental
solution of them, a “nanocoating” is created. This coating is
impact in terms of energy, water consumption, and toxic-harmful
very thin, with a thickness of a few tens of nanometres, and
compounds of heavy metals. However, they are not always efficient
it is able to react directly by forming primary (or covalent)
in terms of quality: although the effectiveness of nanotechnology
chemical bonds with the organic polymers of liquid or powder
processes has improved, this does not always reach the levels of
finishes. Compared with other nanotechnology pre-treatment
microcrystalline phosphating. With the aim of filling this gap, in the last
methods available on the market, the nanocoating created
two years Chemtec’s R&D lab has tested and developed the application
by the PRONORTEC process is highly hydrophobic because
of organic phosphorus compounds through a new, innovative
it is substantially free of hydrophilic metals and, therefore, it
pre-treatment process for metal surfaces called PRONORTEC.
guarantees a high corrosion resistance degree.
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N. 61 - JANUARY/FEBRUARY 2020 - international PAINT&COATING magazine