Photocatalytic substrate and process for producing the same
A photocatalytic substrate comprises a textile support and a finish on the surface thereof. The finish on the surface of the textile support comprises a particulate photocatalytic material and a binder. A process for producing a photocatalytic substrate comprises the steps of providing a textile support having at least one surface, providing a coating composition, applying the coating composition to at least a portion of the surface of the textile support, and drying the surface of the textile support to which the coating composition was applied to produce a photocatalytic substrate.
1 . A photocatalytic substrate, the substrate comprising:
(a) a textile support having at least one surface, and
(b) a finish on the surface of the support, the finish comprising:
(i) a particulate photocatalytic material comprising a plurality of primary particles, the photocatalytic material being present in the finish in an amount of about 0.05 to about 2 wt. % based on the total weight of the substrate, and
(ii) a binder, the binder being present in the finish in an amount sufficient to provide a ratio, by weight, of photocatalytic material to binder of about 1:0.1 to about 1:5,
wherein the finish on the surface of the textile support comprises a plurality of agglomerates of the primary particles of the photocatalytic material, and wherein the agglomerates have a porous outer surface.
2 . The photocatalytic substrate of claim 1 , wherein the textile support comprises polyester-containing yarns, and the yarns are provided in a woven or knit construction.
3 . The photocatalytic substrate of claim 1 , wherein the particulate photocatalytic material comprises a photocatalyst selected from the group consisting of anatase titanium dioxide, molybdenum sulfide, zinc oxide, and combinations thereof.
4 . The photocatalytic substrate of claim 3 , wherein the particulate photocatalytic material comprises fumed, anatase titanium dioxide.
5 . The photocatalytic substrate of claim 1 , wherein the photocatalytic material is present in the finish in an amount of about 0.5 to about 1 wt. % based on the total weight of the substrate.
6 . The photocatalytic substrate of claim 1 , wherein the binder is an organic binder is selected from the group consisting of latex, polyacrylates, vinyl esters, polyurethanes, polyethylene-vinyl acetate, polyolefins, polyesters, polyamides, polyethers, poly(styrene-co-butadiene), polyisoprene, polychloroprene, and combinations thereof.
7 . The photocatalytic substrate of claim 6 , wherein the binder is a latex binder.
8 . A process for producing a photocatalytic substrate, the process comprising the steps of:
(a) providing a textile support having at least one surface,
(b) providing a coating composition, the coating composition being prepared by:
(i) providing a liquid medium,
(ii) dispersing a dry, particulate photocatalytic material in the liquid medium, and
(iii) adding a binder to the liquid medium produced in step (ii) to produce a coating composition,
the coating composition comprising about 0.2 to about 1 wt. %, based on the total weight thereof, of the photocatalytic material and an amount of binder sufficient to provide a ratio, by weight, of photocatalytic material to binder of about 1:0.1 to about 1:5,
(c) applying the coating composition to at least a portion of the surface of the textile support, and
(d) drying the surface of the textile support to which the coating composition was applied to produce a photocatalytic substrate.
9 . The process of claim 8 , wherein the textile support comprises polyester-containing yarns, and the yarns are provided in a woven or knit construction.
10 . The process of claim 8 , wherein the particulate photocatalytic material comprises a photocatalyst selected from the group consisting of anatase titanium dioxide, molybdenum sulfide, zinc oxide, and combinations thereof.
11 . The process of claim 10 , wherein the particulate photocatalytic material comprises fumed, anatase titanium dioxide.
12 . The process of claim 8 , wherein the photocatalytic material is present on the surface of the support in an amount of about 0.5 to about 1 wt. % based on the total weight of the substrate.
13 . The process of claim 8 , wherein the binder is an organic binder is selected from the group consisting of latex, polyacrylates, vinyl esters, polyurethanes, polyethylene-vinyl acetate, polyolefins, polyesters, polyamides, polyethers, poly(styrene-co-butadiene), polyisoprene, polychloroprene, and combinations thereof.
14 . The process of claim 13 , wherein the binder is a latex binder.
15 . The process of claim 8 , wherein the coating composition further comprises a dispersant selected from the group consisting of phosphate esters, ammonia, ammonium hydroxide, and combinations thereof.
16 . The process of claim 15 , wherein the dispersant is added to the liquid medium prior to the addition of the binder.