WO2023119217A1 - Substrat superhydrophobe et revêtement glaciophobe, son procédé d'obtention et substrat ainsi revêtu - Google Patents

Substrat superhydrophobe et revêtement glaciophobe, son procédé d'obtention et substrat ainsi revêtu Download PDF

Info

Publication number
WO2023119217A1
WO2023119217A1 PCT/IB2022/062672 IB2022062672W WO2023119217A1 WO 2023119217 A1 WO2023119217 A1 WO 2023119217A1 IB 2022062672 W IB2022062672 W IB 2022062672W WO 2023119217 A1 WO2023119217 A1 WO 2023119217A1
Authority
WO
WIPO (PCT)
Prior art keywords
layer
mixture
coating
substrate
superimposed
Prior art date
Application number
PCT/IB2022/062672
Other languages
English (en)
Inventor
Filomena Piscitelli
Original Assignee
C.I.R.A. (Centro Italiano Ricerche Aerospaziali) - S.C.P.A.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by C.I.R.A. (Centro Italiano Ricerche Aerospaziali) - S.C.P.A. filed Critical C.I.R.A. (Centro Italiano Ricerche Aerospaziali) - S.C.P.A.
Publication of WO2023119217A1 publication Critical patent/WO2023119217A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/02—Emulsion paints including aerosols
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D5/00—Coating compositions, e.g. paints, varnishes or lacquers, characterised by their physical nature or the effects produced; Filling pastes
    • C09D5/16—Antifouling paints; Underwater paints

Definitions

  • the present invention relates to a method for forming a superhydrophobic and icephobic coating on a substrate having the characteristics set out in the main claim and a coated substrate thus obtained.
  • JU is supported by the European Union Research and Innovation Programme Horizon 2020 and by Clean Sky 2 JU members other than the European Union.
  • the present invention is preferably, though non-exclusively, applied to the aeronautics sector, a sector to which reference will be made hereinafter without losing generality, but it can also be applied to other sectors, such as the automotive, aerospace, construction, shipbuilding, packaging and textile sectors.
  • ice is formed on aircraft surfaces when passing through clouds under atmospheric conditions which encourage the formation of sub-cooled liquid water, i.e. water which remains liquid at temperatures below zero, and which solidifies when it impacts the surfaces of the aircraft.
  • sub-cooled liquid water i.e. water which remains liquid at temperatures below zero
  • solidifies when it impacts the surfaces of the aircraft.
  • the presence of ice on aircraft surfaces affects the aerodynamics of flight, reducing lift and increasing weight and drag, leading to dangerous aircraft stall conditions.
  • ice protection systems are active systems, i.e. which involve consuming energy to prevent ice from forming (anti-icing systems) or to remove it once it has formed (de-icing systems).
  • anti-icing systems anti-icing systems
  • de-icing systems de-icing systems
  • Most of these systems are of the thermal, electrical, electromechanical or pneumatic type, and their use entails an increase in the construction complexity, resulting in a consequent increase in aircraft manufacturing and maintenance costs, as well as a general increase in energy consumption, due to the energy required to operate the system, as well as an increase in the weight of the aircraft itself. All this also has obvious repercussions in terms of environmental impact.
  • Such systems are typically superhydrophobic and icephobic coatings and are promising in terms of reducing implementation and maintenance costs; they also do not lead to an increase in the weight of the aircraft itself and therefore do not increase fuel consumption thereof [1-2].
  • Such coatings may, for example, reduce and/or delay ice formation [3], or they may reduce the adhesion force of the ice to the aircraft surface, which may then be swept away by external forces, such as aerodynamic forces or gravity [4-11], or they may work on both fronts.
  • passive systems represent the only possible protection system; on the other hand, in large aircraft, which typically fly at higher altitudes and in harsher weather conditions, traditional active systems may be used in combination with passive systems, reducing energy consumption [12-14] and environmental impact thereof.
  • passive systems have the further advantage that they may also be applied to those parts for which no installation of protection system is normally provided due to the complexity of construction and management resulting therefrom, such as the rear areas of the wings and tail, where water from the front zone solidifies, with a phenomenon technically defined as run-back icing, which instead requires the installation of active protection systems.
  • tests under various icing conditions have shown that the application of superhydrophobic coatings significantly reduces or completely prevents the formation of run-back ice [14].
  • the problem underlying the present invention is to make available a coating that is functionally designed to overcome the limitations set forth above with reference to the mentioned prior art and a corresponding method for obtaining it.
  • the present invention in a first aspect thereof, relates to a multilayer coating R. for a substrate S comprising at least one layer Al suitable for coating such a substrate S and at least one layer Bl coating the layer Al, said layer Al being constituted by drying a layer of a mixture A comprising one or more polymeric resins and one or more solvents, and said layer Bl being constituted by drying a layer of a mixture B comprising nanometric silica functionalised with hydrophobic functional groups, at least one fluoroalkylsilane and one or more solvents.
  • a substrate S refers to any surface, of whatever nature, such as a metal, ceramic, polymeric, composite, wood, fabric, etc. surface.
  • a multilayer coating R refers to a coating consisting of a number of layers greater than 1, such layers equally having a composition different from, or equal to each other.
  • a multilayer coating R refers to a multilayer coating of any substrate or surface. In this case, it refers to a multilayer covering R of the substrate S.
  • multilayer coating and multilayer covering are to be understood as a multilayer coating R or a multilayer covering R of the substrate S, and such terms may be used interchangeably.
  • polymeric resin is used in the present disclosure to both refer to thermosetting polymer prepolymers and fully cross-linked thermosets, such as epoxy resins, polyurethane resins, silicone resins, acrylic resins and mixtures thereof.
  • a superhydrophobic surface typically refers to a surface that exhibits a contact angle 0 with water greater than 150°, although some studies define a surface as superhydrophobic starting from 145° [39].
  • a superhydrophobic coating refers to a coating that exhibits a contact angle 0 with water greater than 150°.
  • an icephobic coating may be defined as a coating which reduces the formation of ice on a given surface and/or reduces its adhesion thereto.
  • Hydrophobic functional groups refer to functional groups capable of making a surface hydrophobic.
  • the present invention in a second aspect thereof, relates to a method for making a multilayer coating R on a substrate S comprising the steps of: a) preparing the substrate S, b) coating the substrate S with the layer Al, applying a layer of the mixture A to the substrate S and allowing it to partially dry, c) coating the layer Al with the layer Bl, applying a layer of mixture B to the layer Al and allowing it to dry, so as to form a multilayer structure A1B1 on the substrate S in which the layer Al is interposed between the layer Bl and the substrate S.
  • Partial drying refers to a process of partial evaporation of the solvent and/or partial cross-linking of the polymeric matrix.
  • the corresponding partially dried layer is not fully cured when it is coated with the next layer.
  • a layer of mixture A is applied to the substrate and is partially dried to form the layer Al.
  • Layer Al therefore refers to a layer of mixture A which is partially dried when it is coated with the next layer, i.e. in step c) of the above- referred method.
  • Layer Bl refers to a dried layer of mixture B.
  • the present invention in a third aspect thereof, also relates to a coated substrate RS obtained by such a method.
  • the substrate S thus coated will acquire the characteristics of the multilayer coating R, in particular superhydrophobicity and icephobicity, making it particularly suitable for aeronautical applications.
  • the layer Al is a base layer, also referred to as a primer, whose purpose is to facilitate the adhesion of the layer Bl to the substrate S.
  • the mixture A comprises one or more polymeric resins.
  • polymeric resins are selected from the group consisting of epoxy resins, polyurethane resins, silicone resins, acrylic resins and mixtures thereof.
  • polymer resins consist of polyurethane resins or epoxy resins, more preferably are polymeric resins consisting of epoxy resins.
  • the corresponding mixture also comprises one or more crosslinking agents.
  • the crosslinking agents are one or more amines.
  • the solvents of mixture A are selected from the group consisting of tetrahydrofuran (THF), ethyl alcohol, isopropyl alcohol, xylene, and mixtures thereof.
  • THF tetrahydrofuran
  • ethyl alcohol ethyl alcohol
  • isopropyl alcohol ethyl alcohol
  • xylene xylene
  • Such solvents are preferably present in a percentage comprised between 99.9 to 50 wt% of the total polymeric resins in the mixture A.
  • the mixture A further comprises nanometric silica functionalised with hydrophobic functional groups, a coupling agent for coupling the functionalised nanometric silica with one or more of the polymeric resins, a catalyst for coupling the nanometric silica with one or more of such polymeric resins, and a fluoroalkylsilane.
  • the adhesion of the layer Al to the layer Bl is given by the coupling agent present in the partially dried layer Al, which forms a chemical bond, on the one hand, with the hydroxyl groups present on the nanometric silica present in both mixture A and in mixture B, on the other hand, with the one or more polymeric resins present in the layer Al.
  • the multilayer coating R. thus obtained also has a higher wear and rubbing strength.
  • Fluoroalkylsilane can chemically bind to the free sites of silica nanoparticles or interact with them by means of hydrogen bonds.
  • fluoroalkylsilane helps to reduce the surface energy of the coating and consequently increase the contact angle thereof.
  • fluoroalkylsilane in mixture B is present from 5 to 30 wt% of the total components of mixture B, preferably from 7 to 23 wt%.
  • the mixture B comprises one or more polymeric resins.
  • the mixture B is free of polymeric resins.
  • the mixture B comprises 0.5 to 15 wt% of nanometric silica functionalised with hydrophobic functional groups relative to the total of the components of mixture B, more preferably the mixture B comprises 0.5 to 7 wt%.
  • the nanometric silica of mixture A and/or mixture B is functionalised by treatment with hexamethyldisilazane, polydimethylsiloxane, aminosilane, methacrylsilane or fluoroalkylsilane.
  • Nanometric silicas with different functionalisations may be present inside the mixture A and/or mixture B.
  • the functionalised silica in mixture A is the same as in mixture B.
  • the coupling agent is a bifunctional organosilane, most preferably selected from the group consisting of aminoalkoxysilane, isocyanatoalkylsilane, methacrylsilane, vinylsilane and epoxyalkoxysilane.
  • aminoalkoxysilane is an aminopropyltriethoxysilane.
  • isocyanatoalkylsilane is an isocyanatopropyltriethoxysilane.
  • vinylsilane is a vinyltrimethoxysilane or a tris(trimethylsiloxy)vinylsilane.
  • epoxyalkoxysilane is glycidoxypropyltrimethoxysilane.
  • the catalyst for coupling nanometric silica with one or more of the polymeric resins is dibutyltin dilaurate.
  • the resin of the mixture A is an epoxy resin, preferably having a viscosity at 25°C in the range of 500 to 700 mPas and/or a density in the range of 1.13 to 1.17 g/ml.
  • the coating also comprises a layer B2 superimposed on the layer Bl and a layer B3 superimposed on the layer B2 to form a multilayer structure A1B1B2B3 in which the layers are superimposed on each other in the order A1B1B2B3.
  • such a multilayer structure A1B1B2B3 is superimposed one or more times on another multilayer structure A1B1B2B3 to form a repeated multilayer structure (AlBlB2B3)n, with n being an integer indicating the number of repetitions comprised between 2 and 5, the layers B2 and B3 being formed by each drying one layer of the mixture B.
  • n is preferably equal to 2.
  • the coating comprises a layer A2 superimposed on the layer Bl, a layer B2 superimposed on the layer A2 and a layer B3 superimposed on the layer B2 so as to form a multilayer structure A1B1A2B2B3 wherein the layers are superimposed on one another in the order A1B1A2B2B3, such a multilayer structure A1B1A2B2B3 being superimposed one or more times on another multilayer structure A1B1A2B2B3 to form a repeated multilayer structure (AlBlA2B2B3)n, with n being an integer and indicating the number of repetitions and comprised between 2 and 5, the layer A2 being formed by drying one layer of the mixture A and the layers B2 and B3 by each drying one layer of the mixture B.
  • n is preferably equal to 2.
  • the mixture A preferably comprises nanometric silica functionalised with hydrophobic functional groups, a coupling agent for coupling the functionalised nanometric silica with one or more of the polymeric resins, a catalyst for coupling the nanometric silica with one or more of the polymeric resins, and a fluoroalkylsilane.
  • the multilayer coating R comprises a final layer Bf superimposed on the previous layers to form a repeated multilayer structure (AlBlB2B3)nBf or (AlBlA2B2B3) n Bf, the layer Bf being constituted by drying a layer of the mixture B.
  • the layer Bf is formed by drying a layer of the mixture B comprising one or more polymeric resins; preferably such one or more polymeric resins are the same as the mixture A.
  • such one or more polymeric resins are present from 0.1 to 20 wt% relative to the total of the mixture B.
  • a cross-linking agent is also present.
  • the substrate S may be pre-treated before being coated with the multilayer coating R, e.g. by increasing the surface roughness and/or cleaning it appropriately and/or applying adhesion promoters, such as coupling agents.
  • adhesion promoters such as coupling agents.
  • Such coupling agents are for example bifunctional organosilanes, preferably selected from the group consisting of aminoalkoxysilanes, isocyanatedalkylsilanes, methacrylsilanes, vinylsilanes and epoxyalkoxysilanes.
  • this allows to improve the adhesion of the multilayer coating R to the substrate S.
  • the substrate S undergoes a treatment that increases its surface roughness by using sandpaper or sandblasting before being coated with the multilayer coating R, most preferably by sandblasting.
  • a roughness of the substrate S in the range of 2 to 5 microns proved to be particularly effective in ensuring a good adhesion between the substrate S and the multilayer coating R.
  • the method comprises a step d) of coating the layer Bl with one or more layers of the mixture B superimposed on each other.
  • the steps b)-d) are repeated in consecutive order n times, with n being an integer comprised between 2 and 5; preferably n is equal to 2.
  • a final step e) of coating the last layer of the multilayer coating R with a final layer Bf superimposed on the previously applied layers is carried out by applying a layer of the mixture B and allowing it to dry.
  • the layer of the mixture A is partially dried for a time comprised between 2 minutes and 1 hour, more preferably comprised between 5 minutes and 30 minutes, even more preferably between 8 minutes and 15 minutes.
  • the layer of the mixture A is partially dried at a temperature comprised between 60 and 95 °C, more preferably between 65 and 90 °C, even more preferably between 70 and 80 °C.
  • step c) the layer of the mixture B is dried for a time comprised between 1 minute and 40 minutes, more preferably between 3 minutes and 30 minutes, even more preferably between 3 minutes and 20 minutes.
  • the layer of the mixture B is dried at a temperature comprised between 60 and 95 °C, preferably between 70 and 90 °C, more preferably between 70 and 80 °C.
  • the multilayer coating R undergoes a final drying step for a time comprised between 1 hour and 48 hours, more preferably between 8 hours and 36 hours, even more preferably between 15 and 30 hours.
  • the multilayer coating R undergoes a final drying step at a temperature comprised between 60 and 95 °C, preferably between 70 and 90 °C, more preferably between 75 and 85 °C.
  • one or more of the coating layers are applied by spray application, preferably all the layers are applied by spray application.
  • FIG. 1 shows the images of a contact angle of two different substrates S without a multilayer coating R and having a multilayer coating R according to different embodiments;
  • FIG. 2 shows the values related to surface free energy (SFE), work of adhesion (WA) and surface polarity (SP) of three different substrates S without a multilayer coating R and having a multilayer coating R according to different embodiments of the invention;
  • Figure 3 shows the images related to an adhesion test performed on a substrate S having a multilayer coating R according to a first embodiment ( Figure 3a) and a second embodiment ( Figure 3b) of the invention;
  • FIG. 4 shows the results of the tests carried out in IWT on two airfoils; each profile being coated on a half with a multilayer coating R, according to a first embodiment and according to a second embodiment of the invention;
  • FIG. 5a shows a schematic drawing of an airfoil tested in IWT
  • FIGS. 5b and 5c show the length value Ld of the compact ice zone formed on an airfoil with and without a multilayer coating R according to a first embodiment of the invention and according to a second embodiment of the invention subjected to IWT, and
  • FIG. 6 shows the results of a rubbing test performed on a substrate S with and without a multilayer coating R according to the invention.
  • a substrate S consisting of an epoxy resin and carbon fibre composite painted with a commercial paint specifically for aeronautical applications and identified hereinafter with C, a stainless steel substrate, identified hereinafter with I, and an ABS (acrylonitrile-butadiene-styrene terpolymer) substrate, identified hereinafter with ABS, were used.
  • the substrates C and I were used in the form of flat plates measuring 5x5 cmxcm, while the ABS substrate was used in the form of a NACA0015-scale airfoil produced by a 3D printing machine, with a length of 135 mm and a chord of 100 mm.
  • the mixture A was prepared with two different formulations, AFO and AF1. In both cases, a two-component epoxy resin was used, wherein the component resl constitutes the resin and res2 the crosslinker.
  • the two components resl and res2 of the two-component epoxy resin were mixed in a weight ratio of 77:23 resl :res2 with a magnetic stirrer for 10 minutes at room temperature.
  • Aerosil R.812 silica by Evonik and THF were mixed by sonication for 30 minutes; then 3-glycidoxypropyltrimethoxysilane (GPTMS) and dibutyltin dilaurate (DBTDL) were added; the mixture was kept under magnetic stirring at 200 rpm at 65 °C for 1 hour in a water bath in a closed vessel.
  • fluoroalkylsilane Protectosil® SC Concentrate, Evonik Industries AG
  • EtOH ethyl alcohol
  • the quantities of the various components Fl are: 1.55 wt% GPTMS, 1.76 wt% Aerosil R.812 silica, 68.40 wt% THF, 0.38 wt% DBTDL, 8.88 wt% fluoroalkylsilane, 19.03 wt% EtOH.
  • the mixture Fl was added to the component resl of the epoxy resin and the whole was kept under mechanical stirring for 10 minutes at room temperature.
  • the layers Al and A2 were each made by applying a layer of mixture A by airbrush and performing partial drying for 10 minutes at 75 °C. Tests were also conducted with partial drying for 10 minutes at 80 °C, obtaining the same results.
  • Aerosil R.812 silica was mixed with THF and sonicated for 30 minutes at room temperature.
  • THF was used at 97.5 wt% total silica+THF.
  • a mixture of fluoroalkylsilane and ethyl alcohol was prepared separately, and kept under stirring on a magnetic stirrer at room temperature for 10 minutes.
  • the quantities of the various components of B used are the following: 53.92 wt% THF, 30 wt% ethyl alcohol, 14.7 wt% fluoroalkylsilane and 1.38 wt% Aerosil R812 silica.
  • the layers Bl, B2 and B3 were each obtained by applying one layer of mixture B by airbrush; each layer was dried for 10 minutes at 75 °C. Tests were also conducted by drying each layer for 10 minutes at 80 °C and obtaining the same results.
  • the layer Bf was obtained by applying a layer of mixture B by airbrush and by drying for 30 minutes at 75°C and then for 24 hours at 80°C. Tests were also conducted by performing the first 30-minute drying at 80°C and obtaining the same results.
  • Each layer was applied by drop airbrush provided with a 1.2-mm-opening nozzle, with an inlet pressure of dehumidified air of 3 bars.
  • the distance between the airbrush and substrate S was kept between 5 and 30 cm, trying to keep it preferably between 5 and 20 cm. It was also noted that the same results were obtained at a distance comprised between 10 and 30 cm.
  • the coated substrate SR consists of a layer Bf superimposed on a layer B3, superimposed on a layer B2, superimposed on a layer Bl, superimposed on a layer Al, superimposed on a layer B3, superimposed on a layer B2, superimposed on a layer Bl, superimposed on a layer Al which is deposited on the substrate S
  • the coated substrate SR consists of a layer Bf superimposed on a layer B3, superimposed on a layer B2, superimposed on a layer A2, superimposed on a layer Bl, superimposed on a layer Al, superimposed on a layer B3, superimposed on a layer B2, superimposed on a layer A2, superimposed on a layer Bl, superimposed on a layer Al that is deposited on the substrate S.
  • Table 1 Composition of the coating layers COA1 and COAT2
  • a substrate S consisting of a flat plate made of a composite of epoxy resin and carbon fibre was used.
  • the substrate S was pre-treated with aminopropyltrimethoxysilane applied by airbrush, and placed in an oven at 80 °C for 15 minutes.
  • the mixture A was prepared with the formulation AF1.
  • the layer Al was made by applying one layer of the mixture A by means of airbrush and partial drying for 10 minutes at 80 °C.
  • the mixture B was prepared by mixing 4 components Ba, Bb, Be and Bd.
  • the mixture Ba consisted of 9.78 g fluoroalkylsilane, 19.95 g ethyl alcohol, 1.84 g Aerosil 812 and 34.93 g THF.
  • the mixture Bb consisted of 0.36 g GPTMS, 0.41 g Aerosil R.812, 16.03 g THF, 0.09 g DBTDL, 2.08 g fluorioalkylsilane, 4.46 g ethyl alcohol.
  • the mixture Be consisted of 7.73 g of Resl from Example 1, and the mixture Bd consisted of 2.2 g of Res2 from Example 1.
  • weight ratio Ba/Bb/Bc/Bd used was 66.5/23.45/7.73/2.32.
  • the mixture B was prepared by first mixing Be and Bd and leaving it under stirring for 10 minutes, then adding Bb and leaving it under stirring again for 10 minutes and finally adding Ba, leaving it under stirring again for 10 minutes, still at room temperature.
  • This mixture B was applied by airbrush and partially dried for 15 minutes at
  • the mixture B was prepared as for the layer Bl, but the weight ratio Ba/Bb/Bc/Bd used was 90/7/2.31/0.69.
  • This mixture was applied by airbrush and partially dried for 15 minutes at 80 °C.
  • the mixture B was prepared as for the layer Bl, but the weight ratio Ba/Bb/Bc/Bd used was 96.65/2.35/0.77/0.23.
  • This mixture was applied by airbrush and partially dried for 15 minutes at 80 °C.
  • the layer Bf was obtained by applying a layer of mixture B having the composition of Example 1 by airbrush and drying for 24 hours at 80 °C.
  • Each layer was applied by drop airbrush provided with a 1.2-mm-opening nozzle, with an inlet pressure of dehumidified air of 3 bars.
  • the distance between the airbrush and the substrate S was kept between 10 and 30 cm.
  • the flat plate of substrate S was kept horizontal while the various layers of the coating were applied.
  • a coating COAT3 was made on the substrate S so as to obtain a coated substrate SR. having the structure S(AlBlB2B3)Bf.
  • the coated substrate SR consists of a layer Bf superimposed on a layer B3, superimposed on a layer B2, superimposed on a layer Bl, superimposed on a layer Al that is deposited on the substrate S.
  • the surface layer Bf, without polymeric resin, is thereby characterised by a higher contact angle than the underlying layers Bl, B2 and B3, while these, with the resin, are characterised by a higher adhesion to the substrate S and a greater mechanical strength than the layer Bf.
  • the gradually decreasing amount of resin going from the layer Bl to the layer B2 and finally to the layer B3 also allows the mechanical properties of the various layers and the entire coating to be modulated accordingly.
  • a coated substrate SR named CA when the adhesion promoter used was aminopropyltrimethoxysilane
  • a coated substrate SR named CG when the adhesion promoter used was gamma-glycidoxypropyltrimethoxysilane, were formed with the coating COAT3, while the substrate S as such was named CR.
  • IWT tests were performed at CIRA - Centro Italiano Ricerche Aerospaziali based in Capua (CE), Italy.
  • CIRA's IWT is a closed- circuit refrigerated aerodynamic tunnel equipped with three test chambers and an open-jet test configuration. Cloud generation is carried out by the Spray Bar System (SBS), which is capable of generating water droplets with diameters (MVD) and concentrations (LWC) corresponding to the envelope prescribed by the specification CS-25 Appendix C, in both continuous and intermittent mode.
  • SBS Spray Bar System
  • IWT tests were performed on airfoils under 4 different conditions, reported in Table 2.
  • LWC Liquid Water Content
  • MVD Median Volumetric Diameter
  • test conditions were selected taking into account the common performance of a CS-23 category aircraft [41], for which the use of passive coatings are essential, as the active ice protection systems (IPS) are not always applicable.
  • IPS active ice protection systems
  • each airfoil was tested by dividing it into two parts, one of which was coated with the multilayer coating R and the other was left uncoated as a reference.
  • the first airfoil therefore had one half named ABS, and therefore without the multilayer coating R, and the other half named ABS1, wherein the multilayer coating R is COATI.
  • the second airfoil had one half named ABS, and therefore without the multilayer coating, and the other half named ABS2, wherein the multilayer coating R is COAT2.
  • the two airfoils were tested simultaneously; on each airfoil, seven marks were preliminarily drawn 2 cm apart in order to allow the measurement of the thickness of the ice tee and the length of the compact ice L Ci formed on the profile from the leading edge, subtracted by the corresponding tee value.
  • the coatings COAT 1 and COAT 2 were applied according to the method of the invention on a substrate S of the C-type and compared with two other coatings FORM1 and FORM2, prepared as described in [42] and [40], respectively, and applied on a substrate S of the C-type.
  • coated substrates are thus referred to as C COATI, C COAT2, C FORM1 and C FORM2 respectively.
  • Figure 1 shows the image of a drop of water deposited on CO, Cl, C2, CR, CA and CG respectively
  • Table 3 shows the contact angle values measured with the three different liquids on CO, Cl, C2, 10, II, 12, CR, CA and CG
  • Figures 2a, 2b and 2c show the corresponding SFE, WA and SP values.
  • the coated substrates Cl, C2, II, 12, CA and CG show a contact angle with water higher than 150 °C.
  • Figure 3 shows, for exemplary purposes, the images of samples II ( Figure 5a) and 12 ( Figure 5b) after having been submitted to the test and the corresponding contact angle images of a water droplet.
  • Figure 4 shows the images of the airfoils, each having the covering only on one half, in the various conditions under which the test was performed.
  • Figure 5 shows a schematic drawing of the ice accumulated on the airfoil ( Figure 5a), wherein, with an angle of attack, which is the angle at which an airfoil slices through a fluid, equal to zero, A represents the stagnation point, tice represents the thickness of the ice at the stagnation point and L Ci represents the length of compact ice formed along the airfoil from the leading edge.
  • an angle of attack which is the angle at which an airfoil slices through a fluid, equal to zero
  • A represents the stagnation point
  • tice represents the thickness of the ice at the stagnation point
  • L Ci represents the length of compact ice formed along the airfoil from the leading edge.
  • the IWT test showed that, for both COATI and COAT2, there is a sliding of the cooled water droplets along the airfoil; in fact, it may be noted the presence of frozen droplets beyond the transition zone. At the same time, the transition zone has a lower density of frozen droplets for the coated sides. In addition, the isolated water droplets retain their spherical shape, once frozen, as at room temperature.
  • the coatings After the de-icing cycles, the coatings retain their superhydrophobic and icephobic characteristics. The tests carried out have shown that, in the reported conditions, the two coatings are able to reduce or completely avoid ice formation.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Wood Science & Technology (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

La présente invention concerne un revêtement multicouche R comprenant au moins une couche A1 recouvrant un tel substrat S et au moins une couche B1 recouvrant la couche A1, ladite couche A1 étant formée par séchage d'une couche d'un mélange A comprenant une ou plusieurs résines polymères et un ou plusieurs solvants, et ladite couche B1 étant formée par séchage d'une couche d'un mélange B comprenant de la silice nanométrique fonctionnalisée avec des groupes fonctionnels hydrophobes, au moins un fluoroalkylsilane et un ou plusieurs solvants.
PCT/IB2022/062672 2021-12-23 2022-12-22 Substrat superhydrophobe et revêtement glaciophobe, son procédé d'obtention et substrat ainsi revêtu WO2023119217A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102021000032444A IT202100032444A1 (it) 2021-12-23 2021-12-23 Rivestimento superidrofobico e ghiacciofobico di un substrato, metodo per il suo ottenimento e substrato così rivestito
IT102021000032444 2021-12-23

Publications (1)

Publication Number Publication Date
WO2023119217A1 true WO2023119217A1 (fr) 2023-06-29

Family

ID=80625492

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2022/062672 WO2023119217A1 (fr) 2021-12-23 2022-12-22 Substrat superhydrophobe et revêtement glaciophobe, son procédé d'obtention et substrat ainsi revêtu

Country Status (2)

Country Link
IT (1) IT202100032444A1 (fr)
WO (1) WO2023119217A1 (fr)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004104116A1 (fr) * 2003-05-20 2004-12-02 Dsm Ip Assets B.V. Revetements hydrophobes contenant des nanoparticules reactives
CN110845937A (zh) * 2019-11-25 2020-02-28 成都普瑞斯特新材料有限公司 无溶剂管道内壁防腐疏水涂料及其制备方法
CN111154396A (zh) * 2019-11-06 2020-05-15 清远市电创电力工程安装有限公司 纳米二氧化硅改性硅树脂超疏水涂层及制备方法和应用

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9637658B2 (en) 2013-06-24 2017-05-02 The Boeing Company Coatings, coating compositions, and methods of delaying ice formation
US20190127841A1 (en) 2017-09-18 2019-05-02 Nanocoatings, Inc. Fabrication of superhydrophobic and icephobic coatings by nanolayered coating method

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2004104116A1 (fr) * 2003-05-20 2004-12-02 Dsm Ip Assets B.V. Revetements hydrophobes contenant des nanoparticules reactives
CN111154396A (zh) * 2019-11-06 2020-05-15 清远市电创电力工程安装有限公司 纳米二氧化硅改性硅树脂超疏水涂层及制备方法和应用
CN110845937A (zh) * 2019-11-25 2020-02-28 成都普瑞斯特新材料有限公司 无溶剂管道内壁防腐疏水涂料及其制备方法

Also Published As

Publication number Publication date
IT202100032444A1 (it) 2023-06-23

Similar Documents

Publication Publication Date Title
Wang et al. Scalable superhydrophobic coating with controllable wettability and investigations of its drag reduction
Naderizadeh et al. Interfacing superhydrophobic silica nanoparticle films with graphene and thermoplastic polyurethane for wear/abrasion resistance
CN104910776B (zh) 一种透明耐磨超疏水涂料及其制备方法和涂覆工艺
Yu et al. Facile preparation of durable superhydrophobic coating with self-cleaning property
Lv et al. A facile method for constructing a superhydrophobic zinc coating on a steel surface with anti-corrosion and drag-reduction properties
Wang et al. A robust superhydrophobic PVDF composite coating with wear/corrosion-resistance properties
Cheng et al. Improving the durability of a drag-reducing nanocoating by enhancing its mechanical stability
Piscitelli et al. On a simplified method to produce hydrophobic coatings for aeronautical applications
US8999438B2 (en) Systems and methods for super-hydrophobic and super-oleophobic surface treatments
Ruan et al. Superhydrophobic and anti-icing properties of sol–gel prepared alumina coatings
WO2009118552A1 (fr) Revêtements superhydrophobes et leur procédé de fabrication
Lei et al. Mechanically robust superhydrophobic polyurethane coating for anti-icing application
Lv et al. Robust icephobic epoxy coating using maleic anhydride as a crosslinking agent
CA2739903A1 (fr) Revetements super hydrophobes, oleophobes et antigivre a haute durabilite, et procedes et compositions pour leur preparation
Ma et al. Robust photothermal self-healing superhydrophobic coating based on carbon nanosphere/carbon nanotube composite
Nanda et al. Self-assembled monolayer of functionalized silica microparticles for self-cleaning applications
Fu et al. Robust superhydrophobic coating with carbon nanotubes and silica nanoparticles in the matrix of fluorinated polyurethane
Laad et al. Fabrication techniques of superhydrophobic coatings: A comprehensive review
Jiao et al. Mechanically robust superamphiphobic ceramic coatings with releasable nanoparticle-capsules
Chen et al. Highly transparent, stable, and superhydrophobic coatings based on gradient structure design and fast regeneration from physical damage
Lei et al. Facile design and fabrication of highly transparent and hydrophobic coatings on glass with anti-scratch property via surface dewetting
Wei et al. Highly transparent superhydrophobic thin film with low refractive index prepared by one-step coating of modified silica nanoparticles
Huang et al. Fabrication of mechanochemically robust superhydrophobic coating based on MPVDF/epoxy resins composites
Xu et al. Fabrication of superhydrophobic polymer films with hierarchical silver microbowl array structures
Li et al. Improvements of adhesion strength of water-based epoxy resin on carbon fiber reinforced polymer (CFRP) composites via building surface roughness using modified silica particles

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 22844684

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2022844684

Country of ref document: EP

Effective date: 20240723