Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/62—Plasma-deposition of organic layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D5/00—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures
  • B05D5/08—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface
  • B05D5/083—Processes for applying liquids or other fluent materials to surfaces to obtain special surface effects, finishes or structures to obtain an anti-friction or anti-adhesive surface involving the use of fluoropolymers

Definitions

• the invention relates to the deposition of thin layers of hydrophobic compounds on the surface of a substrate.
• the present invention is intended to provide a method for depositing a fluorinated layer from a precursor monomer that avoids the disadvantages of existing processes. In particular, it tries to avoid the need to operate under reduced pressure. It also aims to allow the use of liquid monomers, easier to handle than gaseous monomers and often less toxicologically and environmentally controversial. Summary of the invention
• the present invention relates to a method for depositing a fluorinated layer on a substrate, comprising injecting a gaseous mixture comprising a fluorinated compound and a carrier gas into a discharge or post-discharge zone of an atmospheric cold plasma at a pressure of between 0.8 and 1.2 bar, characterized in that said fluorinated compound has a boiling point at a pressure of 1 bar greater than 25 ° C.
• Atmospheric plasma or “atmospheric cold plasma” or “non-thermal atmospheric plasma” means a partially or totally ionized gas which comprises electrons, ions (molecular or atomic), atoms or molecules, and radicals, out of thermodynamic equilibrium, whose electron temperature is significantly greater than that of ions and neutrals, and whose pressure is between about 1 mbar and about 1200 mbar, preferably between 800 and 1200 mbar.
• the method comprises the steps of: bringing the carrier gas into contact with the liquid fluorinated compound; saturating said carrier gas with vapor of said fluorinated compound to form a gaseous mixture; bringing said gas mixture into the discharge zone of an atmospheric plasma; placing a substrate in the discharge or post-discharge zone of said atmospheric plasma.
• said fluorinated compound does not comprise a hydrogen atom or an oxygen atom.
• the method does not include post-treatment without plasma.
• the fluorinated compound is a compound selected from the group consisting of CeF 4 , C 7 F 6 , C 8 F S, C 8 F 2 O and C 10 F 22, or a mixture thereof.
• the fluorinated compound is perfluorohexane (CeFi 4 ).
• the fluorinated compound is of the type: where R 1, R 2 and R 3 are perfluoroalkane groups of formula C n F 2n + 1, or a mixture of these compounds.
• the fluorinated compound is perfluorotributylamine ((C 4 Fg) 3 N) (CAS No. 311-89-7).
• the vapor pressure of said fluorinated compound at room temperature is between 1 mbar and 1 bar.
• the partial pressure of said fluorinated compound in said carrier gas is regulated by controlling the temperature of a bath of said fluorinated compound in which the carrier gas is injected before injection into the plasma. .
• the temperature of the bath is maintained at a temperature at which the vapor pressure of said compound is less than 10 mbar, preferably less than 2 mbar.
• said fluorinated compound has a vapor pressure at 25 ° C of less than 10 mbar, preferably less than 2 mbar.
• the atmospheric plasma is produced by a device of the dielectric barrier type.
• the atmospheric plasma is produced by a device of the type using microwaves.
• the carrier gas is a low-reactivity gas selected from the group consisting of: nitrogen and rare gas or mixtures thereof, preferably a rare gas or a mixture of rare gas, preferably Argon.
• the substrate comprises a deposition surface comprising a polymer, in particular PVC or polyethylene.
• the substrate comprises a deposition surface comprising a metal, or a metal alloy, in particular steel.
• the substrate comprises a deposition surface comprising a glass, in particular a glass comprising amorphous silica.
• Figure 1 General view of an atmospheric plasma deposition system
• Figure 2 Sectional view of a cylindrical deposition system.
• Figure 3 XPS Spectroscopy (X-ray P_hotoelectron Spectroscopy, in French, X-ray photoelectron spectroscopy) of the sample treated in Example 2
• Figure 4 Detail of the XPS spectrum of the sample treated in Example 2, carbon peak Figure 5 shows the XPS spectrum of untreated PVC.
• Figure 6 shows the XPS spectrum of untreated polyethylene.
• Figure 7 shows the XPS spectrum of the sample processed in Example 4.
• Figure 8 shows the XPS spectrum of the steel after cleaning, and before deposition.
• Figure 9 shows the XPS spectrum of the sample treated in Example 6.
• Figure 10 shows the XPS spectrum of the sample processed in Example 8.
• Figure 11 shows the XPS spectrum of polytetrafluoroethylene (PTFE).
• the present invention discloses a method of depositing a fluorinated polymeric layer by plasma technology operating at atmospheric pressure. It makes it possible to deposit a fluoropolymer layer via a fluorinated compound that is injected into the plasma, or into the post-discharge zone thereof.
• the monomer is a liquid at room temperature
• the plasma is generated in a dielectric barrier discharge, the sample to be treated being placed inside the discharge, or at the immediate exit thereof (post-discharge).
• the partial pressure of fluorinated compound in the plasma is maintained at low values, preferably less than 10 mbar. This low pressure is obtained either by maintaining the fluorinated liquid at low temperature, or by selecting a fluorinated liquid having a vapor pressure of less than 10 mbar at room temperature.
• the use of these low concentrations of fluorinated compounds in the plasma allows in particular the deposition of ultra-thin layers, which allows to obtain transparent layers. Moreover, the adhesive properties and wettability being essentially related to interactions at very short distances, the thinness of the deposit does not degrade these properties.
• the present invention also has the advantage of allowing to treat any surface as far as the geometry of the discharge is adapted, and has the advantage of proceeding in a single step, simple and fast.
• the fluorinated compound is of the type: where R 1, R 2 and R 3 are perfluoroalkane groups of formula C n F 2n + i •
• R 1, R 2 and R 3 are perfluoroalkane groups of formula C n F 2n + i •
• the advantage of this type of molecule lies in the weakness of the CN bond (2.8 eV of binding energy) relative to at the CC bond (4.9 eV of binding energy) favoring a fragmentation pattern of the precursor in the plasma producing radicals -Ri, -R 2 and -R 3 , and thus allowing better control of the nature reactive species within the plasma discharge and in the post-discharge zone thereof.
• the use of this type of molecule induces the incorporation of a small amount of nitrogen into the deposited film.
• the long fragments improve the properties of the deposited layers.
• Perfluorotributylamine (C 4 F 9 ) 3 N) in particular has demonstrated excellent properties.
• the substrate is made of PVC (polyvinyl chloride) film, PE (polyethylene), steel or glass, without this being limiting, being understood for the man of the art that this technology is immediately transferable to all types of substrate. Examples of realization
• Example 1 shows a PVC perfluorohexane deposit produced in post-discharge under the following conditions:
• a sample 3, in the form of a 4 cm by 4 cm PVC film, of the Solvay brand is cut, cleaned with methanol and isooctane and placed at the outlet (at 0.05 cm) from a cold plasma torch ( Figure 1) (Dielectric barrier discharge) operating at atmospheric pressure.
• the fluorinated monomer (perfluorohexane) is placed in a glass bubbler (pyrex) immersed in a Dewar vessel containing a mixture of acetone and dry ice.
• the temperature of the mixture, and therefore of the monomer is about -80 ° C.
• the vapor pressure of the perfluorohexane at this temperature is about 1.2 mbar.
• a stream of argon is then sent into the bubbler, with an overpressure of 1.375 bar at the start.
• the argon / perfluorohexane gas mixture 1 is carried to the inside of the torch.
• a plasma is initiated at a voltage of 3200 volts and a frequency of 16 kHz for 1 minute.
• Example 2 shows a PVC perfluorohexane deposit produced in a dielectric barrier discharge under the following conditions
• the sample is attached to the inside of the outer electrode 9 of a cylindrical dielectric barrier discharge.
• the "hot” electrode 8 the one to which the voltage is applied, is the internal electrode, covered with a bucket of alumina.
• the fluorinated monomer is introduced into the discharge as in Example 1.
• a 1 minute treatment at a voltage of 3000 V and a frequency of 20 kHz is applied thereafter (treatment in discharge zone).
• FIGS. 3 and 4 show a full survey and a magnification of the carbon zone.
• the presence of fluorine CF 2 groups is clearly identified via the peak of fluorine located at 689 eV and the position of the peak of carbon, 291.5 eV corresponds well to carbon -CF 2 -.
• Example 3 is identical to Example 1, except for the substrate, which in this example is polyethylene.
• Example 4 is identical to Example 1, except for the substrate, which in this example is polyethylene.
• Example 4 is identical to Example 2, except for the substrate, which in this example is polyethylene.
• the spectrum of a PE sample ( Figure 6) contains a main peak around 285eV. It corresponds to carbon
• Example 5 a deposition of a fluorinated layer on a steel substrate was made according to the same deposition protocol as for Examples 1 and 3, except that the monomer is this time perfluortributylamine, the temperature is maintained at 25 ° C. The vapor pressure of perfluorotributylamine at 25 ° C is 1.75 mbar.
• Example 6
• Example 6 a deposition of a fluorinated layer on a steel substrate was made following the same deposition protocol as for Examples 2 and 4, except that the monomer is this time perfluortributylamine, which the temperature is maintained at 25 ° C.
• the vapor pressure of perfluorotributylamine at 25 ° C. is 1.75 mbar, which makes it possible to use it at ambient temperature.
• XPS X-ray photoelectron spectroscopy
• the main components are 689.7 eV (Fis) and 292.1 eV (CIs), type CF 2 .
• the new component is around 400 eV and corresponds to nitrogen (NIs).
• the calculated composition is 62.2% of fluorine, 33.3% of carbon and 4.5% of nitrogen.
• the nitrogen component is present only when using the nitrogen-containing monomer (Ci 2 F 27 N).
• Example 7 a deposition of a fluorinated layer on a glass substrate was made following the same deposition protocol as for Example 5.
• Example 8 a deposition of a fluorinated layer on a glass substrate was made following the same deposition protocol as for Example 5.
• Example 8 a deposition of a fluorinated layer on a glass substrate was made according to the same deposition protocol as for Example 6.
• the main components are 689.7 eV (Fis) and 292.1 eV (CIs), type CF2.
• the new component is around 400 eV and corresponds to nitrogen (NIs).
• the calculated composition is 63.0% fluorine, 32.8% carbon and 4.2% nitrogen.
• a sample prepared according to Example 2 was subjected to one week aging in the atmosphere at room temperature.
• EXAMPLE 10 (Comparative) A sample of PVC was exposed to an atmospheric argon plasma, in the post-discharge zone, according to the same experimental scheme as in Example 1, in the absence of the fluorinated monomer.
• Example 11 (Comparative) A PVC sample was exposed to an atmospheric argon plasma, in a discharge zone, according to the same experimental scheme as in Example 2, in the absence of the fluorinated monomer.
• the peak energy as well as the surface composition obtained after treatment are very close to the values obtained for a sample of PTFE.
• the PTFE spectra (FIG. 11) presented in the literature also include 2 peaks. One at 689.7 eV corresponding to fluorine and the other at 292.5 eV corresponding to carbon (CIs).
• the surface composition is 66.6% fluorine and 33.4% carbon. Table 1 shows the contact angles of the water on the surfaces of the various examples and on the surfaces of the untreated substrates.
• the deposited polymer layers are perfectly transparent and invisible to the naked eye.
• the method can be applied to all cold atmospheric plasmas, whatever the mode of injection of energy (not only DBD, but RF, microwave, ).
• the process can be applied to all surfaces to be covered by a fluoride layer: glass, steel, polymer, ceramic, paint, metal, metal oxide, mixed, gel.
• a hydrophobic layer may be deposited only if the starting monomer does not contain oxygen or hydrogen. Indeed, on the one hand, the presence in the plasma discharge, or in the zone of postdischarge of oxygen radicals induces in a direct way the incorporation of hydrophilic oxygen function in the deposited layer, on the other hand, the presence of hydrogenated radicals generally induces their recombination with residual oxygen or moisture, giving rise to the appearance of OH-radicals, very hydrophilic.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Chemical Vapour Deposition (AREA)
• Physical Vapour Deposition (AREA)
• Surface Treatment Of Glass (AREA)
• Formation Of Insulating Films (AREA)
• Coating Of Shaped Articles Made Of Macromolecular Substances (AREA)
• Other Resins Obtained By Reactions Not Involving Carbon-To-Carbon Unsaturated Bonds (AREA)

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• 2008
  • 2008-09-05 CN CN200880110572A patent/CN101821020A/zh active Pending
  • 2008-09-05 JP JP2010523519A patent/JP2010538161A/ja active Pending
  • 2008-09-05 CA CA2698629A patent/CA2698629A1/en not_active Abandoned
  • 2008-09-05 US US12/676,692 patent/US20110014395A1/en not_active Abandoned
  • 2008-09-05 EP EP08803783A patent/EP2192997A2/de not_active Withdrawn
  • 2008-09-05 WO PCT/EP2008/061814 patent/WO2009030763A2/fr not_active Ceased

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