Substrate having photocatalytic and activated carbon constituents and process for producing
Provided herein is a photocatalytic substrate comprising a textile support and a finish on at least a first surface thereof. The finish on at least the first surface of the textile support comprises a particulate photocatalytic material and a binder. On the opposite surface of the textile support is disposed a coating comprising activated carbon particles and a binder. Also provided is a process for producing such photocatalytic substrates.
1 . A photocatalytic substrate, the substrate comprising:
(a) a textile support having first surface and a second surface opposite the first surface,
(b) a first finish disposed on the first surface of the textile support, the first finish comprising (i) a particulate photocatalytic material comprising a plurality of primary particles, and (ii) a first binder, 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, and
(c) a second finish disposed on the second surface of the textile support, the second finish comprising activated carbon particles and a second binder.
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 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 . The photocatalytic substrate of claim 1 , wherein the first binder is present in the first 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.
9 . The photocatalytic substrate of claim 1 , wherein the activated carbon particles are selected from the group consisting of activated carbon particles derived from phenol formaldehyde resins, Chinese coal, and combinations thereof.
10 . A process for producing a photocatalytic substrate, the process comprising the steps of:
(a) providing a textile support having a first surface and a second surface opposite the first surface,
(b) providing a first coating composition, the first 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 first binder to the liquid medium produced in step (ii) to produce a coating composition, the coating composition comprising an amount of photocatalytic material and an amount of the first 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 first coating composition to at least a portion of the first surface of the textile support,
(d) drying the portion of the first surface of the textile support to which the first coating composition was applied,
(e) providing a second coating composition, the second coating composition comprising activated carbon particles and a second binder,
(f) applying the second coating composition to at least a portion of the second surface of the textile support, and
(g) drying the portion of the second surface of the textile support to which the second coating composition was applied to produce a photocatalytic substrate.
11 . The process of claim 10 , wherein the textile support comprises polyester-containing yarns, and the yarns are provided in a woven or knit construction.
12 . The process of claim 10 , wherein the particulate photocatalytic material comprises a photocatalyst selected from the group consisting of anatase titanium dioxide, molybdenum sulfide, zinc oxide, and combinations thereof.
13 . The process of claim 12 , wherein the particulate photocatalytic material comprises fumed, anatase titanium dioxide.
14 . The process of claim 10 , 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.
15 . The process of claim 10 , 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.
16 . The process of claim 15 , wherein the binder is a latex binder.
17 . The process of claim 10 , wherein the coating composition further comprises a dispersant selected from the group consisting of phosphate esters, ammonia, ammonium hydroxide, and combinations thereof.
18 . The process of claim 17 , wherein the dispersant is added to the liquid medium prior to the addition of the binder.
19 . The process of claim 10 , wherein the activated carbon particles are selected from the group consisting of activated carbon particles derived from phenol formaldehyde resins, Chinese coal, and combinations thereof.