Self-cleaning substrates and methods for making the same
View Patent ↗A methods, apparatus and compositions for producing colored, self-cleaning substrates by roll coating are provided. The roll coated, colored, self-cleaning substrates retain the predetermined color and a predetermined gloss of the colored coating, thereby facilitating their use in architectural applications. The roll coated, colored, self-cleaning substrates may be iridescent-free.
1. A method comprising:
(a) first producing a colored aluminum sheet product, the first producing step comprising:
(i) first roll coating a colored coating liquid onto an aluminum alloy sheet; and
(ii) first converting the colored coating liquid into a colored layer, wherein the colored layer is located on an outer surface of the aluminum alloy sheet;
(b) second producing an intermediate aluminum sheet product, the second producing step comprising:
(i) second roll coating an inorganic barrier coating liquid onto at least a portion of the colored layer of the colored aluminum sheet product, wherein the inorganic barrier coating liquid is in the form of an aqueous solution comprising silica; and
(ii) second converting the inorganic barrier coating liquid into an inorganic barrier layer, wherein, after the second converting step, the inorganic barrier layer is located on at least a portion of the colored layer; and
(c) third producing a colored self-cleaning aluminum sheet product, the third producing comprising:
(i) third roll coating a portion of an aqueous-based self-cleaning coating precursor liquid onto at least a portion of the inorganic barrier layer of the intermediate aluminum sheet product;
wherein, the self-cleaning coating liquid includes photocatalytically active semiconductor particles;
(ii) third converting the aqueous-based self-cleaning coating precursor liquid into a self-cleaning layer, wherein, after the third converting step:
(A) the self-cleaning layer is located on at least a portion of the inorganic barrier layer;
(B) the photocatalytically active semiconductor particles are uniformly dispersed throughout the self-cleaning layer.
2. The method of claim 1 , wherein the third producing step comprises:
agitating the aqueous-based self-cleaning coating precursor liquid inside a coating reservoir; and
applying the self-cleaning precursor liquid to the inorganic barrier layer.
3. The method of claim 2 , wherein the agitating step comprises continuous agitation.