Self-cleaning article and a process for preparing the same
View Patent ↗Provided is a composition for forming a photocatalytic coating layer, a process for preparing said composition, a self-cleaning article comprising a photocatalytic coating layer comprising said composition and a process for preparing said self-cleaning article. The composition may be used to prepare a self-cleaning article having excellent anticorrosion and processability by one coating and drying procedure, without several coating and drying procedures.
1. A self-cleaning article comprising:
a steel sheet; and
a coating layer applied on said steel sheet,
wherein said coating layer consists of a composition consisting of a cohydrolysis condensate of i) an SiO 2 sol, ii) silane, and iii) a TiO 2 sol with photocatalytic TiO 2 ,
wherein Si present in said silane and said SiO 2 sol and Ti present in said TiO 2 sol are chemically bonded, said cohydrolysis condensate comprises a unit of —Si—O—Ti—providing TiO 2 at a surface of the coating layer,
wherein said SiO 2 sol is a sol in which silica in a nano size is water-dispersed, and silica has a diameter of 5 to 20 nm, a content ratio of said silica included in said SiO 2 sol is 20 to 40% by weight,
wherein said SiO 2 sol is an acidic or neutral SiO 2 sol,
wherein said Sio 2 sol is included in an amount of 1 to 20 parts by weight, based on 100 total parts by weight of said composition,
wherein said silane is included in an amount of 1 to 30 parts by weight, based on 100 total parts by weight of said composition, said silane is a combination of a trifunctional silane and a tetrafunctional silane,
wherein said TiO 2 sol is a sol in which TiO 2 is water-dispersed, and said TiO 2 sol is an acidic or neutral TiO 2 sol,
wherein said TiO 2 sol is included in an amount of 5 to 60 parts by weight, based on 100 total parts by weight of said composition,
wherein said composition further consists of an additive for anticorrosion and a phosphoric acid, said additive for anticorrosion is selected from the group consisting of an organic acid salt, an inorganic acid salt, and a hydroxide of a metal, said metal is chemically coupled to said Si present in said silane and said SiO 2 sol to form a unit of —Si—O-M-,
wherein M is at least one metal selected from the group consisting of V and Zr,
wherein said additive for anticorrosion is included in an amount of 0.1 to 5 parts by weight, based on 100 total parts by weight of said composition.
2. The self-cleaning article of claim 1 , wherein said additive for anticorrosion is said hydroxide of said metal, said metal is chemically coupled to said Si present in said silane and said SiO 2 sol to form said unit of —Si—O-M-, wherein M is at least one metal selected from the group consisting of V and Zr.