| abstract |
To provide an article having a water-repellent surface, which has excellent water repellency and abrasion resistance. n An article having a water-repellent layer comprising the following inner layer and the following surface layer, on a surface of a substrate, and characterized in that the surface of the water-repellent layer has (a) a surface area ratio (S ratio) of from 1.01 to 1.40, (b) an average surface roughness (Ra) of from 3 to 80 nm, (c) a root-mean-square surface roughness (RMS) of from 3 to 90 nm, (d) an absolute value of the difference between the average surface roughness (Ra) and the root-mean-square surface roughness (RMS) of at most 20 nm and (e) a maximum peak-valley difference (P-V) of from 40 to 600 nm:n Inner layer: A layer which is formed by sintering a mixture of metal oxide spherical fine particles (A) having a mean primary particle size of from 1 to 60 nm and metal oxide spherical fine particles (B) having a mean primary particle size of from 50 to 300 nm, provided that the difference in the mean primary particle size between the metal oxide spherical fine particles (A) and the metal oxide spherical fine particles (B) is at least 20 nm and the proportion of the metal oxide spherical fine particles (A) to the total of the metal oxide spherical fine particles (A) and the metal oxide spherical fine particles (B) is more than 30 mass % and at most 60 mass %, and which has a thickness of at most 5 times the mean primary particle size of the metal oxide spherical fine particles (B), Surface layer: A layer which comprises hydrophobized metal oxide fine particles (C) whose mean primary particle size is from 1 to 20 nm and a metal oxide binder, provided that the metal oxide binder is made of a binder material containing a metal compound (D) which becomes a metal oxide by a hydrolytic condensation reaction or thermal decomposition, and in which the hydrophobized metal oxide fine particles (C) adhere to the surface of the spherical fine particles present on the upper side of the inner layer. |