US 4,180,482 A · Self-cleaning catalytic coating

Abstract

A coating formed on a surface of an article, which is heated during use as typified by a cooking device, to accomplish catalytic oxidation decomposition of oil and grease spattered thereon. The coating is fundamentally a porous matrix layer of an inorganic binder having a matte surface and comprises, in the form of uniformly dispersed particles, an oxidation catalyst and a nondiscoloring material, for example a ferrite, which has the effect of concealing a change in color of the oxidation catalyst resulting from its catalytic action. Preferably the coating comprises additionally a solid acid catalyst such as a zeolite as a decomposition-inducing catalyst in order to acquire an improved catalytic self-cleaning ability at relatively low temperatures such as 200.degree.-300.degree. C.

Claims20

Dependent claims

In an article to be heated during use having a self-cleaning coating formed on a surface thereof that decomposes oils and greases spattered thereon to gaseous substances by catalytic oxidation, in which said self-cleaning coating comprises a porous matrix layer of an inorganic binder containing a matting agent which affords a matte surface to said matrix layer;

a catalyst in the form of particles dispersed uniformly in said matrix layer, said catalyst comprising an oxidation catalyst that catalyzes oxidative decomposition of fatty acids at elevated temperatures and that has a tendency to undergo a change in color as the result of its catalytic action;
the improvement comprising said coating containing a double oxide which is in the form of particles dispersed uniformly in said matrix layer and has such a color with stability that said change in color of said oxidation catalyst is concealed, whereby said self-cleaning coating scarcely exhibits a perceptible discoloration on the occurrence of said change in color.

In a cooking device having means for heating a cooking space and having a self-cleaning coating formed on a surface thereof facing the cooking space, said coating decomposing oils and greases spattered thereon to gaseous substances by catalytic oxidation and comprising a porous matrix layer of an inorganic binder containing a matting agent which affords a matte surface to said matrix layer;

a catalyst in the form of particles dispersed uniformly in said matrix layer, said catalyst comprising an oxidation catalyst that catalyzes oxidative decomposition of fatty acids at elevated temperatures and that has a tendency to undergo a change in color as the result of its catalytic action;
the improvement comprising said coating containing a double oxide which is in the form of particles dispersed uniformly in said matrix layer and has such a color with stability that said change in color of said oxidation catalyst is concealed, whereby said self-cleaning coating scarcely exhibits a perceptible discoloration on the occurrence of said change in color.

An article to be heated during use having a self-cleaning coating formed on a surface thereof that decomposes oils and greases spattered thereon to gaseous substances by catalytic oxidation, wherein said self-cleaning coating comprises a porous matrix layer made of a partially fused borosilicate glass frit having a softening temperature in the range from 400.degree. to 750.degree. C.;

a matting agent which is dispersed in said matrix layer to afford a matte surface to said layer and being an oxide selected from the group consisting of alumina, silica and titania;
a catalyst in the form of particles dispersed uniformly in said matrix layer, said catalyst comprising at least one metal oxide selected from the group consisting of manganese dioxide, dimanganese trioxide and cupric oxide as an oxidation catalyst which catalyzes oxidation of fatty acids at elevated temperatures and has a tendency to undergo a change in color as the result of its catalytic action;
and a ferrite expressed by the general formula MO.Fe.sub.2 O.sub.3, wherein M represents a divalent metal atom selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn, said ferrite having such a color with stability that said change in color of said oxidation catalyst is concealed, said ferrite resembling the color of said oxidation catalyst and being in the form of particles dispersed uniformly in said matrix layer, the amount of said ferrite ranging from 10 to 50% by weight of said oxidation catalyst and from 3 to 40% by weight of said self-cleaning coating, whereby said self-cleaning coating scarcely exhibits a perceptible discoloration on the occurrence of said change in color.

A cooking device having means for heating a cooking space and having a self-cleaning coating formed on a surface thereof facing the cooking space, said coating decomposing oils and greases spattered thereon to gaseous substances by catalytic oxidation and comprising a porous matrix layer made of partially fused borosilicate glass frit having a softening temperature in the range from 400.degree. to 750.degree. C.;

a matting agent which is dispersed in said matrix layer to afford a matte surface to said layer and being an oxide selected from the group consisting of alumina, silica and titania;
a catalyst in the form of particles dispersed uniformly in said matrix layer, said catalyst comprising at least one metal oxide selected from the group consisting of manganese dioxide, dimanganese trioxide and cupric oxide as an oxidation catalyst which catalyzes oxidation of fatty acids at elevated temperatures and has a tendency to undergo a change in color as the result of its catalytic action;
and a ferrite expressed by the general formula MO.Fe.sub.2 O.sub.3, wherein M represents a divalent metal atom selected from the group consisting of Mn, Fe, Co, Ni, Cu and Zn, said ferrite having such a color with stability that said change in color of said oxidation catalyst is concealed, said ferrite resembling the color of said oxidation catalyst and being in the form of particles dispersed uniformly in said matrix layer, the amount of said ferrite ranging from 10 to 500% by weight of said oxidation catalyst and from 3 to 40% by weight of said self-cleaning coating, whereby said self-cleaning coating scarcely exhibits a perceptible discoloration on the occurrence of said change in color.

Dependencies are inferred from the claim text.

Self-cleaning catalytic coating

Life of this patent

Self-cleaning catalytic coating

Life of this patent

Abstract

Claims20