Methods for forming omniphobic thermoset compositions and related articles

Abstract

The disclosure relates to methods for forming an omniphobic thermoset composition, such as an omniphobic polyurethane or epoxy composition. First and second thermosetting components are applied to a substrate and partially cured. A functionalized hydrophobic/oleophobic/omniphobic polymer which is reactive with at least the first thermosetting component is then applied to the coated substrate, which is then further cured to form a thermoset omniphobic coating on the substrate. The thermoset omniphobic composition has favorable omniphobic properties, for example as characterized by water and/or oil contact and/or sliding angles. The thermoset omniphobic composition can be used as a coating on any of a variety of substrates to provide omniphobic properties to a surface of the substrate. Such omniphobic coatings can be scratch resistant, ink/paint resistant, and optically clear. The thermoset omniphobic composition can be applied by different coating methods including cast, spin, roll, spray and dip coating methods.

What is claimed is: 
     
         1 . A method for forming an omniphobic coated article, the method comprising:
 applying to a substrate (i) at least one first thermosetting component reactive with a second thermosetting component and a functionalized omniphobic polymer and (ii) at least one second thermosetting component reactive with the first thermosetting component;   reacting the at least one first thermosetting component with the at least one second thermosetting component to form a partially crosslinked reaction product comprising (i) at least some covalent bonds between the first thermosetting component and the second thermosetting component, and (ii) at least some unreacted functional groups reactive with the functionalized omniphobic polymer;   applying to the partially crosslinked reaction product at least one functionalized omniphobic polymer having a glass transition temperature (T g ) of 50° C. or less, the functionalized omniphobic polymer comprising a functional group reactive with the first thermosetting component; and   reacting the unreacted functional groups in the partially crosslinked reaction product with the functionalized omniphobic polymer to form a thermoset omniphobic coating on the substrate.   
     
     
         2 . The method of  claim 1 , wherein the substrate is selected from the group of metal, plastics, a different thermoset material, glass, wood, fabric (or textile), and ceramics. 
     
     
         3 . The method of  claim 1 , wherein applying the first thermosetting component and the second thermosetting component comprises:
 applying to the substrate a mixture comprising (i) the first thermosetting component, (ii) the second thermosetting component, and (iii) optionally a solvent.   
     
     
         4 . The method of  claim 3 , comprising performing one or more of spraying, casting, rolling, and dipping to apply the mixture to the substrate. 
     
     
         5 . The method of  claim 3 , wherein the mixture comprises the solvent. 
     
     
         6 . The method of  claim 5 , further comprising:
 after applying the first thermosetting component and the second thermosetting component to the substrate, drying the substrate to remove the solvent, thereby forming a coating (partially crosslinked) of the first thermosetting component and the second thermosetting component on the substrate.   
     
     
         7 . The method of  claim 1 , further comprising:
 applying to the substrate one or more additives selected from the group consisting of nanoclay, graphene oxide, graphene, silicon dioxide (silica), aluminum oxide, cellulose nanocrystals, carbon nanotubes, titanium dioxide (titania), diatomaceous earth, biocides, pigments, dyes, thermoplastics, and combinations thereof.   
     
     
         8 . The method of  claim 1 , comprising reacting the at least one first thermosetting component with the at least one second thermosetting component to form a partially crosslinked reaction product (i) at temperature from 20° C. to 150° C. and (ii) for a time from 1 min to 300 min. 
     
     
         9 . The method of  claim 1 , wherein applying the functionalized omniphobic polymer comprises:
 applying to the partially crosslinked reaction product a mixture comprising (i) the functionalized omniphobic polymer, and (ii) a solvent.   
     
     
         10 . The method of  claim 9 , further comprising:
 after applying the functionalized omniphobic polymer to the partially crosslinked reaction product, drying the substrate to remove the solvent.   
     
     
         11 . The method of  claim 1 , comprising reacting the unreacted functional groups in the partially crosslinked reaction product with the functionalized omniphobic polymer to form a thermoset omniphobic coating on the substrate (i) at a temperature from 20° C. to 180° C. and (ii) for a time from 1 hr to 24 hr. 
     
     
         12 . The method of  claim 1 , wherein the thermoset omniphobic coating comprises:
 a thermoset polymer comprising a crosslinked backbone, the crosslinked backbone comprising:   (i) first backbone segments having a structure corresponding to a reaction product from the at least one first thermosetting component with at least one of the second thermosetting component and the functionalized omniphobic polymer;   (ii) second backbone segments having a structure corresponding to a reaction product from the functionalized omniphobic polymer with the first thermosetting component;   (iii) third backbone segments having a structure corresponding to a reaction product reaction product from the second thermosetting component with the first thermosetting component;   (iv) first linking groups linking the first backbone segments and the third backbone segments, the first linking groups having a structure corresponding to a reaction product of the first thermosetting component and the second thermosetting component; and   (v) second linking groups linking the first backbone segments and the second backbone segments, the second linking groups having a structure corresponding to a reaction product of the first thermosetting component and the functionalized omniphobic polymer.   
     
     
         13 . The method of  claim 12 , wherein:
 the first backbone segments are present in an amount ranging from 10 wt. % to 90 wt. % relative to the thermoset polymer;   the second backbone segments are present in an amount ranging from 0.01 wt. % to 20 wt. % relative to the thermoset polymer; and   the third backbone segments are present in an amount ranging from 10 wt. % to 90 wt. % relative to the thermoset polymer.   
     
     
         14 . The method of  claim 1 , wherein the functional group of the functionalized omniphobic polymer is selected from the group consisting of epoxide groups, amino groups, isocyanate groups, hydroxyl groups, carboxylic groups, and combinations thereof 
     
     
         15 . The method of  claim 1 , wherein the functionalized omniphobic polymer is selected from the group consisting of functionalized polysiloxanes, functionalized polyperfluoroethers, functionalized polybutadienes, functionalized polyisobutenes, functionalized branched polyolefins, functionalized poly(meth)acrylates, and combinations thereof. 
     
     
         16 . The method of  claim 1 , wherein the functionalized omniphobic polymer comprises a mono-functional functionalized omniphobic polymer. 
     
     
         17 . The method of  claim 1 , wherein the functionalized omniphobic polymer comprises a di-functional functionalized omniphobic polymer. 
     
     
         18 . The method of  claim 1 , wherein the functionalized omniphobic polymer comprises a poly-functional functionalized omniphobic polymer. 
     
     
         19 . The method of  claim 1 , wherein the functionalized omniphobic polymer is a liquid at a temperature in a range from −130° C. to 40° C. 
     
     
         20 . The method of  claim 1 , wherein the functionalized omniphobic polymer has a molecular weight ranging from 300 to 50,000 g/mol. 
     
     
         21 . The method of  claim 1 , wherein the first thermosetting component and the second thermosetting component together correspond to a thermoset polyurethane. 
     
     
         22 . The method of  claim 1 , wherein:
 the first thermosetting component comprises a polyisocyanate or a polyol; and   the second thermosetting component comprises the other of the polyisocyanate and the polyol.   
     
     
         23 . The method of  claim 22 , wherein the polyisocyanate is selected from the group consisting of 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), hydrogenated MDI, xylene diisocyanate (XDI), tetramethylxylol diisocyanate (TMXDI), 4,4′-diphenyl-dimethylmethane diisocyanate, di- and tetraalkyl-diphenylmethane diisocyanate, 4,4′-dibenzyl diiso-cyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, one or more isomers of tolylene diisocyanate (TDI), 1-methyl-2,4-diiso-cyanatocyclohexane, 1,6-diisocyanato-2,2,4-trimethyl-hexane, 1,6-diisocyanato-2,4,4-trimethylhexane, 1-iso-cyanatomethyl-3-isocyanato-1,5,5-trimethylcyclohexane, chlorinated and brominated diisocyanates, phosphorus-containing diisocyanates, 4,4′-diisocyanatophenyl-perfluoroethane, tetramethoxybutane 1,4-diisocyanate, butane 1,4-diisocyanate, hexane 1,6-diisocyanate (HDI), HDI dimer (HDID), HDI trimer (HDIT), HDI biuret, 1,5-pentamethylene diisocyanate (PDI), PDID (dimer of PDI), PDIT (trimer of PDI), PDI biuret, dicyclohexylmethane diisocyanate, cyclohexane 1,4-diisocyanate, ethylene diisocyanate, phthalic acid bisisocyanatoethyl ester, 1-chloromethylphenyl 2,4-diisocyanate, 1-bromomethylphenyl 2,6-diisocyanate, 3,3-bischloromethyl ether 4,4′-diphenyldiisocyanate, trimethylhexamethylene diisocyanate, 1,4-diisocyanato-butane, 1,2-diisocyanatododecane, and combinations thereof. 
     
     
         24 . The method of  claim 22 , wherein the polyol is selected from the group consisting of polyether polyols, hydroxylated (meth)acrylate oligomers, glycerol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, glycerol, trimethylolpropane, 1,2,6-hexanetriol, pentaerythritol, (meth)acrylic polyols, isosorbide, and combinations thereof. 
     
     
         25 . The method of  claim 1 , wherein:
 the first thermosetting component comprises a polyisocyanate;   the second thermosetting component comprises a polyol; and   the functional group of the functionalized omniphobic polymer comprises an amino group.   
     
     
         26 . The method of  claim 1 , the first thermosetting component and the second thermosetting component together correspond to a thermoset. 
     
     
         27 . The method of  claim 1 , wherein:
 the first thermosetting component comprises a polyepoxide or an amine; and   the second thermosetting component comprises the other of the polyepoxide and the amine.   
     
     
         28 . The method of  claim 27 , wherein the polyepoxide is selected from the group consisting of polyepoxide-substituted aromatic hydrocarbons, aliphatic hydrocarbons, cycloaliphatic hydrocarbons, ethers thereof, esters thereof, imines thereof, and combinations thereof. 
     
     
         29 . The method of  claim 27 , wherein the amine is selected from the group consisting of polyamine-substituted aromatic hydrocarbons, aliphatic hydrocarbons, cycloaliphatic hydrocarbons, ethers thereof, esters thereof, imines thereof, and combinations thereof. 
     
     
         30 . The method of  claim 1 , wherein:
 the first thermosetting component comprises an amine;   the second thermosetting component comprises a polyepoxide; and   the functional group of the functionalized omniphobic polymer comprises an isocyanate group.   
     
     
         31 . The method of  claim 1 , the first thermosetting component and the second thermosetting component together correspond to an acrylic thermoset. 
     
     
         32 . The method of  claim 1 , wherein the thermoset omniphobic coating has a water contact angle in a range from 90° to 120°. 
     
     
         33 . The method of  claim 1 , wherein the thermoset omniphobic coating has an oil contact angle in a range from 1° to 65°. 
     
     
         34 . The method of  claim 1 , wherein the thermoset omniphobic coating has a water sliding angle in a range from 1° to 30° for a 75 μl droplet. 
     
     
         35 . The method of  claim 1 , wherein the thermoset omniphobic coating has an oil sliding angle in a range from 1° to 20° for a 25 μl droplet. 
     
     
         36 . The method of  claim 1 , wherein the thermoset omniphobic coating has a thickness ranging from 0.01 μm to 500 μm. 
     
     
         37 . The method of  claim 1 , wherein the thermoset omniphobic coating is scratch-resistant, ink-resistant, and optically clear.