GREEN FRIX
How the plasma process works
Plasma is the fourth state of matter: a highly energized gas full of ions, radicals and excited molecules. Exposing an oil to plasma changes its molecular structure, and with it, its performance.
Cold plasma in the DBD reactor
01
Generate a cold plasma
A dielectric barrier discharge (DBD) energizes hydrogen at reduced pressure. The energy goes to the electrons that drive the reaction, not to heating the oil.
02
Treat the oil in one reactor
The oil, degassed under vacuum, meets the plasma directly. Partial hydrogenation and cross-linking take place in the same vessel.
03
Cross-link the chains
Reactive species open bonds on the fatty-acid chains. Triglycerides link into dimers, then trimers, oligomers and polymers. Viscosity is tracked live and the run stops on target.
What the plasma does to the oil
Polymerization
Larger molecules and higher viscosity, for applications that need thicker, more stable oils.
Oxidation stability and purification
A lower iodine value for a longer shelf life, and fewer impurities and odour-causing compounds.
Surface activation
Adjustable polarity for better compatibility with other ingredients and easier emulsification.
What we control
Gas and pressure
Determine which reactive species form and which reactions follow.
Power and treatment time
Set how far the cross-linking goes, without overheating or degrading the oil.
Viscosity end point
Measured during treatment, so every batch stops at the specified grade.
From oil to polymer: the viscosity we can reach
Kinematic viscosity at 40 °C, logarithmic scale. The longer the cross-linking runs, the further right the product moves.
Oligomers are available in ISO VG 68, 100, 150, 220, 320, 460 and 680. Higher grades on request.
* Indicative ranges. Oligomers and polymers coexist over a wide viscosity range; their proportions at a given viscosity depend on the composition of the starting oil and on the reaction parameters.
The science behind plasma-treated oils
How a cold plasma changes a vegetable oil, where the process comes from, and how we measure the result.
What is a cold plasma, and how does it change a vegetable oil?
A cold plasma is a partially ionized gas in which the electrons carry most of the energy, while the gas and the oil stay at moderate temperature (about 50 to 70 °C in our reactor). We create it by applying an alternating high voltage between electrodes separated by a dielectric barrier, a dielectric barrier discharge (DBD), in hydrogen, for example, at reduced pressure. The working pressure follows Paschen's law, which relates the breakdown voltage of a gas to the product of its pressure and the electrode gap: at reduced pressure, a stable and homogeneous discharge ignites at moderate voltage. The oil flows as a thin film over the electrodes. Under hydrogen, the plasma generates hydrogen radicals. They add to the carbon–carbon double bonds of the unsaturated fatty-acid chains, which removes the double bond and leaves a triglyceride radical; two such radicals recombine into a dimer. Because a triglyceride usually carries several double bonds, the reaction repeats, forming trimers, oligomers and polymers. Other plasma gases can be used: Green Frix also works with oxygen, for example, to make alternatives to blown oils.
Why does a lower iodine value matter?
The iodine value measures how many carbon–carbon double bonds an oil contains. Oxidation starts at these double bonds, so a lower iodine value generally means better oxidation stability and a longer shelf life. Under hydrogen, plasma treatment cross-links the oil and partially hydrogenates it in the same step, without a metal catalyst, so there is no nickel or other catalyst residue to remove.
Oligomer or polymer: what is the difference?
Both are triglycerides linked by covalent bonds: an oligomer contains a few units, a polymer many more. REACH defines a polymer by its molecular-weight distribution: a simple weight majority of molecules with at least three monomer units bound to another unit, and no single molecular weight in majority. Our lower-viscosity grades do not meet that definition and are registered under REACH as oligomers. Oligomers and polymers coexist in the same product; the longer the treatment, the more the distribution shifts towards polymers.
Where does the process come from?
The treatment of liquids by silent electric discharge was invented in Ghent, Belgium, by Professor Alexandre de Hemptinne, who patented it in 1905 (British patent No. 7101). Applied to oils under hydrogen, it was later called voltolization and was used in the first half of the 20th century to thicken lubricating oils. Those reactors were hard to control and gave variable results. Our patented reactor and process (priority 2016) make the treatment controlled and reproducible: a stable high voltage on every electrode, regulated hydrogen pressure, continuous filtration and in-line viscosity measurement.
What changes in the oil, in measurable terms?
In a published example on rapeseed oil (US 2019/0203153 A1), the treatment raised the dynamic viscosity and the weight-average molar mass (GPC, polystyrene equivalent), while the iodine value fell as part of the double bonds were consumed. Our products are specified by these measurable properties: viscosity, iodine value, molar mass and viscoelastic behaviour (thixotropy and relaxation time). They are protected by at least two patent families: WO 2018/002340 for the lower-viscosity grades and WO 2018/002355 for the higher-viscosity grades.
Which oils can be treated, and what protects the technology?
Rapeseed, sunflower, soybean, linseed, castor and argan oils, as well as vegetable waxes in molten form. The reactor, the process and the resulting oils are covered by Green Frix patent families filed since 2016, including US 11,053,453 B2, WO 2018/002340 and WO 2018/002355. All products are developed and produced in Ghislenghien, in Wallonie Picarde (Belgium); our head office is in Blandain.