# US 7,744,953 B2 · Method for forming self-cleaning coating comprising hydrophobically-modified particles > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,744,953 B2 - Document ID: US7744953B2 - Status: Granted - Kind: B2 - Application number: 11/318,566 - Filed: 2005-12-28 - Published: 2006-07-06 - Granted: 2010-06-29 - Earliest claimed: 2004-12-30 - Assignees: Industrial Technology Research Institute - Inventors: Yuan-Chang Huang; Yuung-Ching Sheen; Yih-Her Chang; Kuo-Feng Lo - Web page: https://patentgrep.com/patent/US7744953B2 ## CPC - B05D 5/08: to obtain an anti-friction or anti-adhesive surface (rendering particulate materials free-flowing in general, e.g. making them hydrophobic B01J2/30) - Y10T 428/2809: including irradiated or wave energy treated component - B05D: PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL (conveying articles or workpieces through baths of liquid B65G, e.g. B65G49/02) - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A method for forming self-cleaning coating comprising hydrophobically-modified particles. Micro- or nano-particles are treated with a hydrophobic agent and an additive to form larger particles with the hydrophobic agent and the additive bonded thereto. A binder or crosslinker is attached to the larger particles by forming chemical bonds with at least one of the additive, the hydrophobic agent, and the particles, thus forming a coating material capable of forming self-cleaning coating. ## Claims ### Claim 1 A method for forming a self-cleaning coating on a substrate, comprising the steps of: forming a coating material by providing micro or nano-particles; treating the micro or nano-particles with a hydrophobic agent and an additive to form larger particles with the hydrophobic agent and the additive bonded thereto, wherein the step of treating the micro or nano-particles with the additive and the hydrophobic agent is effected at a pH of about 6.5-14, and wherein the additive promotes hydrolysis and condensation reactions of the micro or nano-particles such that the micro or nano-particles grow into the larger particles; and attaching a binder or crosslinker to the larger particles by reacting the binder or crosslinker with at least one of the additive, the hydrophobic agent, and the particles; applying the coating material to the substrate; and drying or curing the coating material to form a solid coating having a microstructured, hydrophobic surface, wherein the hydrophobic surface of the coating is such that water forms a contact angle of at least 130°. ### Claim 2 (depends on 1) A method as claimed in claim 1, wherein the hydrophobic surface of the coating is such that water forms a contact angle of at least 150°. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein the step of providing micro or nano-particles comprises: providing wet synthesis process precursors; reacting the wet synthesis process precursors to form the micro or nano-particles. ### Claim 4 (depends on 3) The method as claimed in claim 3, wherein the wet synthesis process precursors comprise water, solvent, and metal alkoxide. ### Claim 5 (depends on 4) The method as claimed in claim 4, wherein the metal alkoxide is selected from the group consisting of tetramethoxysilane, tetraethoxysilane, titanium tetraisopropoxide, titanium tetramethoxide, titanium tetraethoxide, titanium tetrabutoxide, and zirconium n-butoxide. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the particles comprise a functional group selected from the group consisting of —SiR, —TiR, —ZrR and —AlR groups, wherein R is OH, COOH, NH2, CONH2, NCO, SH, vinyl, or epoxy. ### Claim 7 (depends on 6) The method as claimed in claim 6, wherein the particles are commercially available silica particles. ### Claim 8 (depends on 1) The method as claimed in claim 1, wherein the micro- or nano-particles have diameters between about 1 nm and 100 μm. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein the larger particle has a size between about 100 nm-1000 μm. ### Claim 10 (depends on 1) The method as claimed in claim 1, wherein the additive comprises a functional group for bonding with the binder or crosslinker. ### Claim 11 (depends on 10) The method as claimed in claim 10, wherein the functional group is selected from the group consisting of vinyl, amino, epoxy, carboxyl, hydroxyl, and isocyanate. ### Claim 12 (depends on 11) The method as claimed in claim 11, wherein the additive comprises functional alkoxysilane. ### Claim 13 (depends on 12) The method as claimed in claim 12, wherein the additive is selected from the group consisting of amino trialkoxysilane, vinyl trialkoxysilane, and epoxy trialkoxysilane. ### Claim 14 (depends on 1) The method as claimed in claim 1, wherein the hydrophobic agent comprises Si-based materials. ### Claim 15 (depends on 1) The method as claimed in claim 1, wherein the hydrophobic agent is selected from the group consisting of F-based materials and hydrocarbon materials. ### Claim 16 (depends on 1) The method as claimed in claim 1, wherein the binder or crosslinker comprises a functional group selected from the group consisting of vinyl, amino, epoxy, carboxyl, hydroxyl, and isocyanate. ### Claim 17 (depends on 16) The method as claimed in claim 16, wherein the binder or crosslinker is selected from the group consisting of epoxy resins, polyureathanes, polyesters, acrylic resins, polyamides, and silicone resins. ### Claim 18 (depends on 1) A method as claimed in claim 1, wherein the coating material is applied to the substrate using spin coating, dip coating, spray coating, brush coating, or roller coating. ### Claim 19 (depends on 1) A method as claimed in claim 1, wherein the step of drying or curing the coating material is conducted at a temperature between room temperature and 200° C. ### Claim 20 (depends on 1) A method as claimed in claim 1, wherein the substrate is selected from the group consisting of glass, metal, ceramic, and polymer. ### Claim 21 (depends on 1) A method as claimed in claim 1, wherein the coating withstands more than 2,000 ASTM D2486 scrub test cycles. ### Claim 22 (depends on 1) The method as claimed in claim 1, wherein the coating passes a JIS K5400 grid adhesion test.