FIELD OF THE INVENTION

The present invention described herein relates to a process of making a hygienic ceramic tile that have ability to reduce microbes greater than Log 2 in 2 hrs tested as per the test standard JIS Z 2801:2006 and ISO 21702:2019.
More particularly, the present invention provides a process of making a hygienic ceramic tile by using a ceramic glaze slip comprising of inter alia Si02, A1203, Na20, K20, ZnO, Zr02, MgO, CaO, B203, Ti02, Cu20, Fe203, BaO, wherein the size of active particles must be preferably below 50 micro-meters.
BACKGROUND OF THE INVENTION
For many centuries, in the history, it is observed many a time that deadly diseases swept across the world creating havoc to mankind. It is also observed that the deadliest diseases are either caused by bacteria or viruses. Moreover, as the civilization developed, the movement of men and women across the world increased and the thereby the outbreaks of infectious diseases also increased; and in recent past have become more frequent. If data for last three decades are analyzed, it is found that every country across the world has done considerably good work in controlling the bacteria and virus that caused infections. However, the new cases and certain ailments, including the latest cases of Ebola, SARS, NIP AH, and COVID-19 have gone up, and scientists attribute these rises to many a reason that includes growing poverty, and increasingly vulnerable population and constantly mutating strains of microbes, including viruses.
In one such survey conducted for the period from year 2000 to year 2015 analyzing the crude death rate for 100,000 population, it was observed that among many diseases that include respiratory diseases, HIV/ADDS, diarrhea, parasitic and vector borne diseases, childhood cluster diseases including measles, tuberculosis, meningitis, STDs, encephalitis, hepatitis and leprosy, the most death occurs from respiratory viral diseases. During these 15 years of time, the death rate was most for the respiratory viral diseases, which though declined varied significantly from

165 (in year 2000) to 85(in year 2015) per 100,000 population in low-income economies to close to 40 to 38 in the respective years, in high income economies having rates with intermediate values among middle class and lower middle-class economies. The rates globally recorded are from 55 (in year 2000) to 42 (in year 2015). Though the mortality rates decreased, overall case load has increased in leaps and bounds. Therefore, it becomes evident for the scientific and technological community to find out remedies that has antimicrobial, more specifically antibacterial and anti-viral efficacy to the ever-changing newer strains.
Many diseases caused by bacteria and viruses are contagious and communicable. These bacteria and viruses get transmitted from one infected person to another in many ways including coughing, exhaling, sneezing, talking in closed spaces and through indirect transmission by touching bacteria and virus laded surfaces. Once the viruses and bacteria are available in air or any other bodily fluid, it may land on walls, floors, and other surfaces of common usage. These bacteria and viruses, depending on their life cycle, may stay alive for long time before they infect other persons. So, these walls and floors play a very important role for communication of these diseases. Therefore, it becomes further evident that if walls and floors can be made actively anti-bacterial and anti-viral, then during the stay of the bacteria and viruses, they will be neutralized and will be in-effective for further spread of infection.
Compared to the last century, more and more households are using industrially produced wall and flooring solutions. The ceramic tiles in many of its avatars have taken the center stage for this kind of industrial grade wall and floors for its easy application and easy wash properties. Over the years, the wall and floor tiles have become de facto the first choice of household owners and consumers in general for applications in interiors and as well as exteriors. Therefore, it has become important for industrial, scientific and technological community to

develop highly potent ceramic flooring and wall solutions which have active antibacterial and anti-viral efficacy.
In ceramic tiles, the anti-microbial efficacy, specifically the anti-bacterial efficacy is tested as per the test standard JIS Z 2801 and the antiviral efficacy is tested as per the test standard ISO 21702. Therefore, an object of the present invention is to provide a ceramic tile suitable for both wall and floor application having high antibacterial and anti-viral efficacy and to provide the industrial manufacturing process to produce such anti-bacterial and anti-viral ceramic tiles.
The above-mentioned information in the background section is only intended to enhance the understanding of the reader with respect to the field to which the present invention pertains. Therefore, unless explicitly stated otherwise, any of the features or aspects discussed above should not be construed as prior art merely because of its inclusion in this section.
In the public domain, a few references are available for manufacturing anti-microbial surfaces. The most relevant documents are analyzed here for their usefulness and limitations.
In the patent US4849223A antimicrobial compositions consisting of metallic silver combined with titanium oxide or tantalum oxide is disclosed. A filler material comprising 20% by weight of Ag coated on Ti02 was prepared by reducing the silver oxide formed on addition of silver nitride to an alkaline slurry of Ti02 with dilute formaldehyde. The resulting Ag on Ti02 antimicrobial composition was spray dried.
Preferably the oligo dynamic metal comprises silver. The hydratable or hydrated oxide component, which in use should be in the hydrated condition, is formed preferably from an element selected from calcium, magnesium, niobium, silicon, tantalum, tin, titanium, zinc, aluminum, zirconium, cobalt, hafnium, lanthanum,

tungsten and cerium. As well as providing the desired enhancement of the antimicrobial effect, hydrated oxides for use according to the invention should, of course, not produce any substantial adverse reaction in biological systems and in body fluids and tissues.
Another document, US9028962B2 discloses a process for the manufacture of transparent cover glass for applications such as touch screen devices that embody antimicrobial properties that includes being antibacterial, antifungal, and antiviral. The antimicrobial glasses contain nanoparticles of Cu or CU2O on the surface of the glass. The antimicrobial glasses can further have a fluoro-silane coating or other coating on the surface to make the glasses easy-to-clean. Also, glass surfaces having an antibacterial or antimicrobial surfaces and a protective coating on the surface that do not inhibit the antibacterial or antimicrobial properties of the glass are described providing a glass substrate selected from the groups consisting of alkali alumino-silicate glass, alkali alumino-boro-silicate glass and soda lime glass. Coating is accomplished through dip-coating, spin coating, slot coating, curtain coating or spray coating onto the surface of the glass from a suspension of Cu, CU2O or CuO nanoparticles in water or solvent. The glass is then heated in an air or an inert atmosphere (for example, nitrogen or helium) to a temperature sufficient to seal the particles to the glass. In an embodiment of a process using CuO as the initial nanoparticles, the process includes a subsequent step to reduce the CuO to Cu nanoparticles. Followed by, heating the CuO nanoparticle coated glass in nitrogen atmosphere (N2) at an ambient pressure of 1 atmosphere to sinter the nanoparticles to the surface of the glass substrate and then strengthening the glass by ion-exchange; reducing the CuO nanoparticles to Cu nanoparticles in H2 for a time in the range of 5 minutes to 2 hours; carrying out a controlled oxidation of the Cu nanoparticles to CU2O nanoparticles and applying a fluoro-silane coating to yield an ion-exchanged glass having Q12O nanoparticles thereon. However, this protective fluoro-silane coating is not durable as it is very thin film and organic in nature, and it will inherently reduce the antimicrobial efficacy of Cu nanoparticles. Here in this description, the active

copper as Cu particles and copper oxide as CU2O are used in a coating on the touch screen glass surfaces, and the organic silane coating only acts as a non-wetting and easy to clean display surface. The antibacterial Cu particles and CU2O are covered by the silanes and therefore, the efficiency of the active antimicrobial materials will be largely hindered.
Yet another patent document US 8,741,197, discloses a process for the manufacture of rayon fiber comprising of microscopic water insoluble particles of copper oxide incorporated in said fibers, wherein a portion of said particles in said fibers are exposed and protruding from the surface of the fibers and wherein said particles release Cu++ ions when exposed to water or water vapor. In another aspect of this invention, there is provided a rayon product comprising microscopic water insoluble particles of copper oxide incorporated in said product wherein a portion of said particles in said product are exposed and protrude from the surface of the product and wherein said particles release Cu++ ions when exposed to water or water vapor. In one embodiment of the invention, particles are of a size of between 0.5 and 2 microns and are present in an amount of between 0.25 and 10% of the cellulose weight. In preferred embodiments of the invention the microscopic water insoluble particles of copper oxide are selected from the group consisting of cupric oxide particles, cuprous oxide particles, and mixtures thereof. Here in this patent description, CuO particles are sprayed on rayon fibers. As the process describes, the longevity of the coating will be very limited and the anti microbial efficiency of the coating on the cloth fiber is washed in subsequent usages.
Yet another patent document, WO2013128302A1 discloses a process for manufacturing ceramic articles such as floor and wall tiles as well as sanitary ware having antifungal, antibacterial and antimicrobial properties comprising the molding, drying, baking (firing) and vitreous glazing stages from clays and hydration agents, characterized in that in said vitreous glazing stage is added to the glazed surface, copper particles with spherical shape being in a standardized

range from 0.5 to 1.5 millimeters (500 microns to 1500 microns) in diameter or cylindrical particles being in a standardized range from 0.5 to 1.5 millimeters (500 microns to 1500 microns) in diameter and 0.5 to 1.0 milli-meters (500 microns to 1000 microns) in length, in a copper ratio on the ceramic article surface between 1 milligram to 10 milligram per cm2 of the ceramic surface. It claimed to have reduced only 70% of bacterial load in 24hrs. Here in the patent description, the antibacterial active component dimensions in the range of 0.5mm to 1.5m are very large and after coated, these will be felt in the glaze surface. Moreover, these particles are so big in nature that the under lying surfaces will never be properly visible. Because of its bigger particles size, the coating spray density must be kept low to avoid any bad feeling while touching the ceramic surfaces.
In yet another patent US5147686A a method of making titanium oxide powder having antimicrobial metal was described. Here the antimicrobial powders are obtained by supporting at least one antimicrobial metal of copper, zinc and alloys thereof on the surface of hydrous titanium oxide represented by TiCh. nH20 or titanium oxide particles by electroless plating, vapor deposition, compression mixing, simple mixing and reducing, and thermal decomposition of a compound.
In yet another patent document US9,974,310, a manufacturing method of ceramic additive formulation is described. The method comprises fritting ( essentially meaning premelting and converting a molten glass of the input materials) an antimicrobial formulation in a flux frit, providing at least one unfritted antimicrobial component, providing a silver carrier in a glass matrix, and combining the flux frit, and at least one unfritted component from the group of ZnO, Bi203, TiCh, Sn02 in a range of 80-90% by weight of the ceramic glaze formulation, and the silver carrier was in the glass matrix to form the ceramic glaze formulation. The silver carrier is combined at an addition rate based on a dry weight basis of the ceramic glaze formulation. As described in this patent, the antimicrobial active component silver is made to go inside a glass matrix while fritting. The frit is then mixed with the other glaze components for the

formulation. The ceramic process formulation requires a firing process wherein the said Silver available as Ag micro particles are encapsulated inside a non-microbial glass coating. The Silver being a noble metal does not react easily even with strong acids and alkalis. Its reaction with the inert glass capsule is also remote. Therefore, no anti-microbial silver particle is present as exposed to do any microbial action for the microbes residing on the ceramic surface. When laboratory experiments were conducted as explained in this patent, the resulting surface failed to yield Log 2 level of any microbial activity as per JIS Z 2801 and ISO 21702 standards.
In yet another patent document US 20140120148 a method of producing a anti-microbial material is described. Here the antimicrobial material is comprised of a porous activated ceramic substrate; a titanium dioxide layer covalently bound to the ceramic substrate; and a silver salt layer covalently bound to the titanium oxide layer which makes a continuous surface on the substrate. This antimicrobial material is used in the antimicrobial devices and methods to reduce or eliminate microorganisms in fluid. The patent describes the how to coat a porous ceramic material with an antimicrobial coating.
In yet another patent document US20090104459, a Ceramic glaze having antimicrobial property is described wherein antimicrobial ceramic glazing composition contains one or more antimicrobial agents such as first agent Ag203, and second agent such as Bi203, CuO, SnO, TiCh or ZnO, wherein both the first and the second microbial agent is available at a concentration range of 2%-4%. It is also reported that Ag203 in addition to 2% CuO has resulted in very weak microbial efficacy. Beside this, addition of 2% CuO leaves a very strong grey black color in the ceramic glaze making the resultant product ready for very limited use.
In yet another patent document US 20180116226 a method of making an already

glazed surface antimicrobial by applying on it an antimicrobial composition that comprises a carrier medium and antimicrobial additive is selected from group consisting of Bi203, ZnO, Ag20, Ag2C03, Zn, Bi, Ag and combination thereof. Here the antimicrobial active components are sprayed on the ceramic surface with an organic dispersion medium. The coating is not a part of the glaze material and will have very low longevity as the handling and usage will abrade the active material off the glazed ceramic surface.
In yet another patent document application US20190075800, for biocidal glazing compositions, a composition of producing the ceramic glaze comprising at least one metal or metal containing compound selected from the group consisting of Cu20, Cu (OH)2, Cu, Cu03, Cu203, and a combination thereof, and at least one non-copper metal or non-copper containing metal compound are described. Non-limiting examples of non-copper metal and non-copper containing metal compounds are Ag, Ag20, Bi, Bi203, Zn, ZnO, or a combination thereof are mentioned. The detail as described in the patent document shows that Combination No. 1 of: 2% Ag20, 2% Bi203, 2% ZnO, and 2% CuO; Combination No. 2 of: 2% Bi203 and 4% ZnO; and Combination No. 3 of: 2% Ag20, 2% Bi203, and 2% ZnO are tested for their antimicrobial efficacy. These oxide compositions were described to have been mixed with slow firing glaze compositions where the glaze essentially contains all natural raw materials, as claimed in the document, and the sanitaryware glazes do not contain premelted frit. Accordingly, the firing teperature, as claimed can go upto 1270C and the firing cycle time goes for as high as 13hrs to 14 hrs. The 6% to 8% addition of these oxides change the other physical properties of the glaze layer such as, smoothness, overall texture, crazing properties, crawling and orange peeling flakiness and inherent color. The inherent colous of the oxides at higher addition level of 2% and more , such as any compounds of copper (Cu) will impart such a dark color to the glaze that no other colour can be rendered into that by adding any other colouring stains. Moreover, at this level of higher addition level of 6%

to 8% metal oxides in glaze may still be melted for a slow firing cycle in a electric or gas fired kiln, or in a tunnel or a shuttle kiln, the same can not be used for any product which are being fired in rapid fast firing Roller Hearth Kiln, where the entire fire cycle is of 35mins to 60mins depending on the thickness of the product and final desired water absorption. So though antibacterial efficacy is achieved, the detailed compositions can not be used for any industrial product realisation through any process employing Rapid Fast Firing in Roller Hearth Kiln, as it is everywhere nowadays.
In yet another patent document CN102797145B, a method of producing an antimicrobial compound is described. Here the antimicrobial active compound comprises of nano titanium dioxide-nano silver mixed solution which is prepared from titanium dioxide water solution with mass concentration being 3-5% and nano silver complex of which the silver content is 500ppm. The nano titanium dioxide-nano silver mixed solution is sprayed or soaked on household items or crops, and cotton fabric immersed in the mixed solution after being dried has self-cleaning and antibacterial functions.
In yet another patent document EP 2435384 Bl, wherein a dry ceramic glazing composition, dry ceramic glazing method and glazed product are disclosed wherein an antimicrobial composition is included in the frit, adhesive or both. The antimicrobial formulations are same as described in the patent US20090104459 described above. In addition to this, the patent also describes a method of applying a dry ceramic glaze layer to a substrate wherein a fritted glaze is deposited on the first glaze layer. Here the fritted glaze and the subsequent adhesive layers contain ZnO or Bi203, CuO, Sn02, Ti02, in addition to Ag2C03 as the first component, at a addition level of 2% to 4%. The sample tiles were fired at cone 5, 1196C. The products were tested as per the JIS Z2801:2000 for antibacterial action.

In yet another patent document, DE10243132A1, a method of manufacture of Anti-infectious, biocompatible titanium oxide coatings for implants. Here an organo-metallic solvent and organo-metallic titanium oxides are applied together on the bio ceramic substrate. Copper and silver ions are also added in multiple coatings for larger availability of active anti-microbial components.
In yet another patent document EPO190504 describes a method of producing antimicrobial by depositing oligo dynamic metallic silver on particles of titanium and /or tantalum oxides or hydroxides.
The careful review of the above prior art reveals that there are some processes demonstrated wherein it is observed to have reduced the microbial load to some extent, though the antimicrobial efficacy never crossed the 90% mark. Moreover, though microbial, that is anti-fungal and anti-bacterial efficacy is reported, anti-viral efficacy is never achieved on any ceramic surfaces.
In view of the above mentioned products and processes disclosed in the patent documents, the features disclosed and the limitations therein, it is an object of the present invention to disclose a novel process of industrially manufacturing a ceramic glaze formulation comprising materials from the list of and not limited to Si02, AI2O3, Na20, K20, ZnO, Zr02, MgO, CaO, B2O3, Fe203, and active material from the list of CU2O, ZnO, both individually and in combination and then applying it on a ceramic tile substrate meant for domestic, commercial, and industrial use to produce an antimicrobial and antiviral ceramic tile that can reduce the bacteria, viruses or fungus available on that surface by more than 99% in 24 hrs. The novel method described in this patent does not use the premelting and fritting process and thereby drastically increases the availability of the active material exposed for antimicrobial and antiviral action.

OBJECTS OF THE INVENTION
The main object of the present invention is to provide an antimicrobial and anti-viral glaze coating composition for manufacture of a hygienic ceramic tile.
Another object of the present invention is to provide a method of making a hygienic ceramic tile that can reduce the microbes including virus to the extent of Log 2 and more in 24 hrs.
Yet another object of the present invention is to provide a process of making a hygienic ceramic tile by using a ceramic glaze slip comprising of inter alia Si02, AI2O3, Na20, K20, ZnO, Zr02, MgO, CaO, B2O3, Ti02, Cu20, Fe203, BaO, wherein the size of active particles must be preferably in range not exceeding 45 micro-meters.
Yet another object of the present invention is to provide a process of making a hygienic ceramic tile which can be produced through a Rapid Fast Firing Process employing Roller Hearth Kilns with cold to cold firing cycle time of the product can be as low as in the range of 35 mins to 60 mins.
Yet another object of the present invention is to provide a process of making a hygienic ceramic tile which can be processed with glazes comprising significantly less addition level of the active metal oxides, so that products can be made with aesthetic appeal, and different colors can be achieved by adding other different ceramic coloring stains.
These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made

within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.
SUMMARY OF THE INVENTION:
The present invention discloses a process of making an active antimicrobial and anti-viral tile by using the glaze slip composition that includes inter alia aluminum oxide, silicon oxide, a mix of sodium and potassium oxide, cuprous oxide, calcium and magnesium oxide and zinc oxide on the ceramic tile surface to make it potential anti-bacterial and anti-viral surface for daily use and longevity.
DESCRIPTION OF INVENTION
The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the detailed following description. Descriptions of well-known components and processing techniques are omitted to not unnecessarily obscure the embodiments herein.
A process of making hygienic ceramic tile is defined herein. The process comprising the steps of:
preparing of a ceramic glaze slip comprising of inter alia Si02, AI2O3, Na20, K2O, ZnO, Zr02, MgO, CaO, B2O3, Ti02, Cu20, Fe203, BaO, wherein the size of active particles must be preferably not greater than 45 micro-meters. Some quantity of ceramic stains may well be added to the glaze to achieve various desired colors.
a) coating of the glaze product thus prepared on the suitable engobe coated green ceramic tiles manufactured by either hydraulic pressed or extruded or through any other suitable processes to get the necessary and sufficient deposition of

the active material resulting in sufficient thickness for it to be resistant to abrasion.
b) firing the glazed tile thus prepared at a temperature range of 1050-1250° C to get silky smooth surface of various textures with various color tints.
The novel process is described in the embodiments with respect to the composition of the active material, composition of the frit materials, compositions of the UNTREATED glaze materials and and composition of the active material TREATED glaze material are detailed in Table 1, Table 2, Table 3, Table 4, and Table 5 respectively.
Table 1 details the various active material oxides used in the experimental trials conducted as explained in this document.
Table 2 details the frit composition used in the various glaze formulations towards making the hygienic ceramic tile.
Table 3 details the composition of the UNTREATED glaze formulations towards comparing with the active material TREATED glaze in hygienic ceramic tile.
Table 4 and 5 detail the various active material TREATED trial glaze compositions in the process of preparing the hygienic tiles.
The novel process also employs suitable procedures for realizing the various properties in the novel product. The procedure for preparation of active materials and procedure for ceramic tile manufacturing are detailed in Figure 1, and Figure 2 respectively.

Figure 1 illustrates a schematic process flow chart of preparing the hygienic active compound that will be used for preparing the suitable glaze for applying on the wall and floor tiles.
Figure 2 illustrates a schematic process flow chart of preparing ceramic tiles comprising of the engobe, glaze and firing of the tiles to achieve a durable ceramic tile.
As per aesthetic requirement, the fired surface of ceramic tile can also be polished. Moreover, various color also can be achieved through addition of multiple ceramic glaze stains to enhance the architectural aesthetic appeal of the surface of ceramic tiles.
The novel invention described in this patent document will be more clearly understood with the help of the following detail embodiments.

Table 1 Hygienic Oxide Composition

Active material Compositions
Active Material Composition % Unit Al A2 A3 A4 A5 A6 A7 A8 A9 A10 All A12
Ti02 0/
/o 50 20 40 100 20 40
Cu20 0/
/o 50 40 50 30 100 40 30
ZnO 0/
/o 40 50 30 100 50 40 30
AgNano 100
CuO 100 50
Total % 100 100 100 100 100 100 100 100 100 100 100 100
Particle size after
attrition milling,
98% less than H 45(i 45(i 45(i 45(i 45(1 45(i 45(1 45(i 45(i 45(i 90(i 90(i
Table 2 Oxide Compositions of the Frits

Si02 AL203 CaO MgO Na20 K20 Ba203 ZnO B203 Zr02
Glossy Glaze frit (Low temp) 46.90 8.21 13.60 2.96 0.84 5.20 0.15 8.65 5.22 8.25
Glossy Glaze Frit (High temp) 50.10 22.90 9.30 2.58 2.42 0.86 1.95 7.89 1.96
Matt Glaze Frit (Low Temp) 47.65 9.75 13.64 3.89 0.82 5.11 1.17 11.05 0.00 6.87
Matt Glaze Frit (High Temp) 50.82 22.70 7.10 3.60 1.80 1.97 2.20 4.07 0.87 4.67

Table 3 Glaze Compositions for Standard Untreated sample and Experimental Results

UNTREATED glaze compositions Antimicrobial -Antiviral Test Standards
Glaze Composition (GC) Addition
0/
/o UT01 UT02 UT03 UT04
Active material addition-% 0/
/o 0 0 0 0
Glossy Glaze Frit (Low temp) 0/
/o 90
Satin Matt Glaze Frit (High Temp) 0/
/o 90
Glossy Glaze Frit (High temp) 0/
/o 90
Matt Glaze Frit (Low Temp) 0/
/o 90
China Clay % 10 10 10 10
Total 100 100 100 100
Tile Firing Temperature c 1125 1190 1180 1120
Firing Cycle time mins 38 52 52 40
Surface Texture Glossy Matt Glossy Matt
Anti Bacterial Efficiacy (2 hrs) 0/
/o 41.20 52.98 60.54 50.98
Anti Viral Efficacy (2 hrs) 0/
/o 54.68 60.84 48.9 46.78

Table 4 TREATED Glaze Compositions and Experimental Results

Antimicrobial Test (1-8) AMI AM2 AM3 AM4 AM5 AM6 AM7 AM8
TREATED Glaze Composition (GC) Addition
% GC1 GC2 GC3 GC4 GC5 GC6 GC7 GC8
Active Microbial Material Type Type Al Al A2 A2 A3 A3 A4 A4
Active material add-% % 3 6 3 6 3 6 3 6
Glossy Glaze Frit (Low temp) % 87 84 84
Satin Matt Glaze Frit (High Temp) % 87 87
Glossy Glaze Frit (High temp) % 84 84
Matt Glaze Frit (Low Temp) % 87
China Clay % 10 10 10 10 10 10 10 10
Total 100 100 100 100 100 100 100 100
Tile Firing Temperature C 1150 1160 1180 1125 1125 1180 1180 1180
Firing Cycle time mins 38 38 47 35 37 53 52 54
Surface Texture Glossy Glossy Satin Matt Glossy Satin Matt Glossy Satin Matt Glossy
Anti Bacterial Efficiacy (2hrs) % 98.26 97.2 98.6 98.1 99.18 99.58 97.08 99.2
Anti Viral Efficacy (2 hrs) % 96.7 96.4 99.12 99.08 99.58 99.5 97.36 99.7
Oxide Contribution from Active Material
Ti02 % 1.5 3.0 0.6 1.2 1.2 2.4
Cu20 % 1.5 3.0 1.2 2.4 1.5 3.0 0.9 1.8
ZnO % 1.2 2.4 1.5 3.0 0.9 1.8
AgNano %
CuO %
Total Active Material % 3 6 3 6 3 6 3 6

Table 5 TREATED Glaze Compositions and Experimental Results

Antimicrobial Test (9-16) AM9 AM10 AMU AM12 AM13 AM14 AM15 AM16 AM17 AM18
Glaze
Composition
(GC) Addition
% GC9 GC10 GC11 GC12 GC13 GC14 GC15 GC16 GC17 GC18
Active Microbial Material Type Type A5 A6 A7 A8 A9 A10 All A12 A3 A3
Active
material
addition-% % 4 4 4 4 4 4 4 4 1.5 7
Glossy Glaze
Frit
(Low temp) % 86 86 88.5 83
Satin Matt Glaze Frit (High Temp) % 86
Glossy Glaze
Frit
(High temp) % 86 86 86 86 86
Matt Glaze
Frit
(Low Temp) %
China Clay % 10 10 10 10 10 10 10 10 10 10
Total 100 100 100 100 100 100 100 100 100 100
Tile Firing Temperature C 1125 1125 1180 1180 1180 1180 1180 1180 1125 1125
Firing Cycle time mins 38 38 48 50 52 52 52 56 38 38
Surface Texture Glossy Glossy Glossy Glossy Glossy Glossy Rough Rough Glossy Rough
Anti Bacterial Efficiacy (2 hrs) % 99.34 98.34 60.54 98.6 88.6 92.34 78.54 52.56 72.54 70.46
Anti Viral Efficacy (2 hrs) % 95.45 88.12 48.9 97.24 64.56 94.56 65.46 68.74 76.44 76.6
Oxide Contribution from Active Material
Ti02 % 4.0 0.8 1.6
Cu20 % 4.0 1.6 1.2 0.75 3.5
ZnO % 4.0 2.0 1.6 1.2 0.75 3.5
AgNano % 4.0
CuO % 4.0 2.0
Total Active Material % 4 4 4 4 4 4 4 4 1.5 7.0

EMBODIMENTS FOR THE NOVEL HYGENIC CERAMIC TILES.
Preparation of the active anti-microbial compounds.
For preparing the active materials for application in the final ceramic glaze composition, various oxide materials are mixed into a desired composition and processed. These oxide compositions are given the identification numbers as Al to A12. Among many oxide compositions, these 12 were specifically shortlisted for detailed tests in the laboratory.
Example 1
In one of the embodiments of the present invention, industrial grade Titanium di Oxide Ti02, and industrial grade cuprous oxide CU2O are weighed and taken in 50:50 ratio to prepare a stock of 2 kg. This mix oxide material is ground in an 92%) alumina lined ball mill with 100%) excess water for 4-5 hrs. The residue of the final ground mix oxide is checked and was ensured that at least 98%> of the ground powder passes through SS rectangular 45-micron (#350 mesh) sieve on dry basis. The residue must not be more that 2% over the selected sieve. The wet-ground mix is then dried in an industrial drier at around 150C for 2hrs to 3 hrs in order to dry the powder to nil residual moisture. For practical purposes, the drying temperature can be kept in the range of 150C to 200C. A residual moisture content of 0.5% is allowed. However, for further processing of these ground mix oxide materials, the residual moisture content must be taken into consideration for mark up. After drying some agglomeration was observed, therefore, the mix was again passed through the selected sieve, stored in an airtight container and was identified as Al.
Example 2

In another laboratory test, industrial grade Titanium di Oxide Ti02, industrial grade cuprous oxide CU2O, and industrial grade ZnO are weighed and taken in 20:40:40 ratio to prepare a stock of 2 kg. As earlier example, this mix oxide material is ground with 100% excess water for 4 hrs. The residue of the final ground mix oxide was ensured to be at least 98% passing through #350 mesh sieve on dry basis. The wet-ground mix is then dried in an industrial drier at a temperature of 175C for 2hrs to nil residual moisture. After drying the mix was again passed through the selected # 350 mesh sieve to get rid of agglomerations, stored in an airtight container and was identified as A2.
Example 3
In yet another laboratory test, industrial grade cuprous oxide CU2O, and industrial grade ZnO are weighed and taken in 50:50 ratio to prepare a stock of 3 kg. As earlier examples, this mix oxide material is ground with 100%) excess water for 4 hrs. The residue of the final ground mix oxide was checked and ensured to be at least 98%o passing through #350 mesh sieve on dry basis. The wet-ground mix is then dried in an industrial drier at a temperature of 175C for 2hrs to nil residual moisture. After drying the mix was again passed through the selected # 350 mesh sieve to get rid of agglomerations and stored in an airtight plastic wrapped container. This powder was identified as A3.
Example 4
In yet another laboratory test, industrial grade Titanium di Oxide Ti02, industrial grade cuprous oxide CU2O, and industrial grade ZnO are weighed and taken in a 40:30:30 ratio to prepare a stock of 3.5 kg. As done in earlier examples, this mix oxide material is wet ground with 100%> excess water for 4 hrs. The residue of the final ground mix oxide was checked and ensured to be at least 98%> passing through #350 mesh sieve on dry basis. The wet-ground mix is then dried in an industrial drier at a temperature of 170C for 2.5hrs to nil residual moisture. After

drying the mix was again passed through the selected #350 mesh sieve to get rid of agglomerations and stored in plastic wrapped airtight container. This powder was identified as A4.
Example 5
In yet another embodiment of the present invention, 3.5 kg of industrial grade black ZnO was taken in a alumina lined ball mill and was wet ground as described in the earlier examples. The oven dried powder was passed through the #350 mesh and ensured that the 98% ground powder mass passes through the mesh. If in the first grinding operation, the desired particle size is not achieved, then further grinding can be continued to achieve the same. In this case total grinding time was 3.5hrs. The ground powder thus realized was oven dried to 0.5% of the residual moisture and passed through the #350 mesh to avoid any agglomeration. This final dry powder was stored in an airtight plastic container for future laboratory trials. This powder was identified as A5. Example 6
In yet another embodiment of the present invention, industrial grade glass frit mixed Nano Silver material (GermGuard - GG-E10, manufactured by Endura IPNR) was taken 2kgs and in order to maintain the similar processing parameters, was milled in an aluminalined ball mill for 10 mins to ascertain that the particle size of the oven dried powder conforms to 98% passing through the #350 mesh. It was observed that the powder was passing 100% through the mesh and did not show any agglomeration on drying. This was stored separately in a plastic container. This powder was identified as A6.
Example 7
In yet another embodiment of the present invention, 2.5 kg of industrial grade Titanium Oxide (manufactured by Indian Rare Earth Ltd) taken in an alumina

lined ball mill and was wet ground for 1.5 hrs as described in the earlier examples. The oven dried powder was passed through the #350 mesh and ensured that the 98% ground powder mass passes through the mesh. The ground powder thus realized was oven dried at 200C to 0.5% residual moisture and passed through the #350 mesh to avoid any agglomeration on drying. This final dry powder was stored in an airtight plastic container for future laboratory trials. This powder was identified as A7.
Example 8
In yet another embodiment of the present invention, 3.5 kg of industrial grade Cuprous Oxide taken in an alumina lined ball mill and was wet ground for 1.5 hrs. The oven dried powder was passed through the #350 mesh and ensured that the 98%) ground powder mass passes through the mesh. The ground powder thus realized was oven dried at 210C to less than 0.5% residual moisture. The dry powder was again passed through the #350 mesh to break any agglomeration on drying. This final dry powder was stored in an airtight plastic container for future laboratory trials. This powder was identified as A8.
Example 9
In yet another embodiment of the present invention, 3.5 kg of industrial grade Cupric Oxide (CuO) taken in an alumina lined ball mill and was wet ground for 1.5 hrs. The oven dried powder was passed through the #350 mesh and ensured that the 98%> ground powder mass passes through the mesh. The ground powder thus realized was oven dried at 210C to less than 0.5% residual moisture. The dry powder was again passed through the #350 mesh to break any agglomeration on drying. This final dry powder was stored in an airtight plastic container for future laboratory trials. This powder was identified as A9.
Example 10

In yet another embodiment of the present invention, 5 kg mix oxide was prepared by mixing of industrial grade black ZnO and industrial grade CuO was taken in a ratio of 50:50, in an alumina lined ball mill and was wet ground as described in the earlier examples. The oven dried powder was passed through the #350 mesh and ensured that the 98% ground powder mass passes through the mesh. The ground powder thus realized was oven dried toremove residual moisture and passed through the #350 mesh to break the agglomerated powder. This final dry powder was stored in an airtight plastic container for future laboratory trials. This powder was identified as A10.
Example 11
In another laboratory test, industrial grade Titanium di Oxide Ti02, industrial grade cuprous oxide CU2O, and industrial grade ZnO are weighed and taken in 20:40:40 ratio to prepare a stock of 4 kg. As in earlier example, this mix oxide material is ground with 100% excess water for 1/2 hrs. The residue of the final ground mix oxide was ensured to be at least 98% passing through #170 mesh sieve on dry basis. The average particle size of 90 micron was achieved. The wet-ground mix is then dried in an industrial drier at a temperature of 225C for 2hrs to almost nil residual moisture in the range of 0.5%. After drying, the mix was again passed through the selected #170 mesh sieve to get rid of agglomerations. This was stored in an airtight container and was identified as Al 1.
Example 12
In yet another laboratory test, industrial grade Titanium di Oxide (Ti02), industrial grade Cuprous Oxide (CU2O), and industrial grade Zinc Oxide (ZnO) are weighed and taken in 40:30:30 ratio to prepare a stock of 5 kg. As in earlier example, this mix oxide material was ground with 100%) excess water for 1/2 hrs. The residue of the final ground mix oxide was ensured to be at least 98%> passing

through #170 mesh sieve on dry basis. The average particle size of 90 micron was achieved. The wet-ground mix is then dried in an industrial drier at a temperature of 225C for 2hrs to almost nil residual moisture in the range of 0.5%. After drying, the mix was again passed through the selected #170 mesh sieve to get rid of agglomerations. This mix oxide material was stored in an airtight container and was identified as A12.
While following these mix oxide compositions, persons skilled in the art may note that the Active Material Composition numbered Al 1, and A12 were prepared with 90-micron average particle size instead of 45-micron. This was done to understand the effect of particle size of the active precursor materials on the antimicrobial potency of the final glaze composition as applied on the ceramic tiles and fired at different temperatures.
The frits for glaze making
Following the preparations of the Active Material Compositions as detailed in the examples from Al to A12, each and all dried materials were subsequently made into a suitable glaze formulation for applying on to the pressed green ceramic tile surface. The suitable glazes were prepared using different low and high temperature frits. The oxide composition of the various frits is detailed in Table 2. The frits contained a set of oxides from the list of Si02, AI2O3, CaO, MgO, Na20, K2O, Ba203, ZnO, B2O3, and Zr02. The frits were remelted glass from various raw materials containing those respective oxides. In case of the present inventions, four types of frit materials were selected. The frits are characterized by their final rendition of surface texture and gloss.
Based on this terminology, both glossy and matt frits were selected which matures at high temperatures, such as, 1175C to 1250C, and that matures at comparatively low temperatures, such as, 1050C to 1125C. In the present embodiment, we shall refer these frits as Glossy Glaze Frit (Low Temperature), Glossy Glaze Frit (High

Temperature), Matt Glaze Frit (Low Temperature), Matt Glaze Frit (High Temperature), Irrespective of the temperature where the frits start melting, the melting range can be modified by adding other raw materials such as china clay and by controlling the particle size of the glaze materials.
Overview of the glaze compositions
The previously prepared active material and the frits were mixed in predetermined glaze compositions (GC) as described in from GC 1 to GC 16 and are detailed in Table 4 for GC 1 to GC 8, and in Table 5 for GC 9 to GC 16. These 16 glaze compositions were prepared with active materials from Al to A12, prepared before and were mixed with the above mentioned 4 types of frits in various addition level.
The rheological properties of the glazes
The residue of the glaze maintained on #350 mesh was essentially that of the frit and other materials. Sufficient floating material such as china clay and rheology modifier such as sodium silicate and sodium tri-poly phosphate were used to achieve the desired flow properties. This followed the general process conventions which is well known to the person skilled in the art. The density and viscosity of the glazes were the process parameters and were maintained as per the process requirements. The nominal viscosity was maintained at 1.85 g/cc to 1.88 g/cc. The glaze flow was maintained at 50s to 60s in B4 Ford Cup for easy and smooth coating application.
After addition of the precursor powders to the desired ceramic glaze and mixing, if micro-bubbles are observed entrapped in the glaze fluid, then commonly available anti-frothing agents can be added drop by drop to the desired level till the bubbles are diminished. The glaze in the embodiments were applied on the ceramic tiles through a glaze applicator for application width of 150mm and

thickness of 0.5mm. Multiple parallel applications were made to cover a tile size of 300mm x 300mm.
Testing for antimicrobial and antiviral efficacy
After the glazed tiles were fired and a final tile was achieved, samples were cut into sizes of 100mm x 100mm and six such pieces were tested for both anti-microbial and antiviral activity as per the test procedures laid down in test standard JIS Z 2801 for anti-bacterial and test standard ISO 21702 for the antiviral efficacy. The test was conducted in designated and accredited biotechnology laboratory traceable both nationally and internationally. For both antimicrobial and antiviral tests, the test samples were tested and compared for their efficacy against a standard untreated sample. This standard untreated sample was prepared from a glaze which did not contain any active antimicrobial or antiviral oxide component in it. The corresponding glaze compositions for this standard which was considered as untreated are detailed in Table 3. Detail of test conditions maintained for antimicrobial activity
Name of the Protocol: JIS Z 2801:2006
Test Culture:
1. Staphylococcus aureus ATCC (1.60 x 105 CFU/ml)
2. Escherichia coli ATCC 11229 (1.70 x 105 CFU/ml)
Test Conditions:
Neutralizer used : Buffered Saline with Tween 80-0.01%
Contact Time : 24 hours at 37C
Incubation Temperature : 37C for bacteria
Media and Reagent : Soyabean-casein digest agar for bacteria

Detail of test conditions maintained for antiviral activity
Name of the Protocol: ISO 21702:2019
Test Microorganism Information:
MS2 Bacteriophage (MS2) is an RNA virus of the family Leviviridae. Escherichia coli 15597 are the hosts for bacteriophages. Due to its environmental resistance, MS2 bacteriophages are used as a surrogate virus (particularly in place of Picomaviruses such as Poliovirus and human Norovirus) in water quality and Anti-microbial studies.
Test Culture:
Sample (50 mm x 50 mm); Pre-sterilized by UV light
Control Carrier: Sample non coated and sterilized by autoclaving (50 mm x 50 mm)
LDPE cover: LDPE film pre sterilized 40 mm x 40 mm
Virus: MS2 Bacteriophage; Inoculum volume 0.4 ml
Permissive Host Cell: Escherichia coli ATCC 15597
Test Condition: Contact Period: 2 hours Neutralizer: DE broth Medium: Trypticase soya agar Incubation for survivors: 37C for 3 days
Percent Reduction Calculation:
PercentRed«ction = {A-B]xVM
A
Where:
A is the number of viable microorganisms before treatment,
B is the number of viable microorganisms after treatment

Log Reduction Calculation
LogReduction=log10(—) B
or,
LogReduction=log10(^4)—log10(5)
Where:
A is the number of viable microorganisms before treatment,
B is the number of viable microorganisms after treatment
Formula used for Conversion of Log Reduction to Percent Reduction and vice versa.
P=(l-10~£)*100
Where:
P is the percent reduction
L is the log reduction
The Standard Antimicrobial Value of Log Reduction = S > 2.0 Corresponding Microbial Reduction percentage = > 99%. For easy understanding of the results, efficacy percentage (%) is reported. The average of multiple test results are reported in the table.
EMBODFMENTS OF THE PRESENT INVENTION
Preparation of the test standards with the untreated glazes

In order to understand the effects of active antimicrobial and antiviral compounds in the specially prepared glazes as mentioned in these novel disclosures, a standard set of glazes were also prepared. In these glaze compositions, no active materials were added. As per the testing nomenclature, these will be identified as untreated. In these disclosures, there are four different types of frits used. In line with those four different types of glazes were made. The compositions of these untreated standard glazes are detailed in the Table 3.
Example 13
In one of the examples of the present inventions, untreated glaze composition UT01 was prepared by mixing 90% Glossy Glaze Frit (Low Temperature), 10% washed china clay for a batch of 2 kg. The resulting mixture was wet ground with 38%) demineralized water in an alumina lined mill. The final glaze residue was 8%> on a #350 mesh. The resulting glaze was applied on a pre-engobed green tile using a glaze applicator, which resembles the Bell application. The tile thus coated had a glaze thickness of 0.5mm, was dried in an industrial oven and fired at 1125C. The fired surface of the glaze was glossy. The fired tile was cut into six pieces of size 100mm x 100mm and tested for antimicrobial and antiviral efficacy. The detail of the antimicrobial and antiviral tests is described in the preceding sections. The antibacterial efficacy and antiviral efficacy were reported at 41.2% and 54.68%) respectively.
Example 14
In yet another example of the present invention, untreated glaze composition UT02 was prepared by mixing 90%> Satin Matt Glaze Frit (High Temperature), 10%o washed china clay for a batch of 2 kg. The resulting mixture was wet ground with 35%o demineralized water in an alumina mill. The final glaze residue was 9.2%o on a #350 mesh. The resulting glaze was applied on a pre-engobed green tile using a glaze strip applicator. The tile thus coated had a glaze thickness of

0.5mm, was dried in an industrial oven and fired at 1190C. The fired surface of the glaze was matt. The fired tile was cut into six pieces of size 100mm x 100mm and tested for antimicrobial and antiviral efficacy. The antibacterial efficacy and antiviral efficacy were reported at 52.98% and 60.84% respectively.
Example 15
In yet another example of the present invention, untreated glaze composition UT03 was prepared by mixing 90% Glossy Glaze Frit (High Temperature), and 10%) washed china clay for a batch of 2 kg. The resulting mixture was wet ground with 35%) demineralized water in an alumina lined mill. The final glaze residue was 8.2%o on a #350 mesh. The resulting glaze was applied on a pre-engobed green tile using a glaze strip applicator. The tile thus coated had a glaze thickness of 0.5mm, was dried in an industrial oven and fired at 1180C. The fired surface of the glaze was glossy. The fired tile was cut into six pieces of size 100mm x 100mm and tested for antimicrobial and antiviral efficacy. The antibacterial efficacy and antiviral efficacy were reported at 60.54%> and 48.9%> respectively.
Example 16
In yet another example of the present invention, untreated glaze composition UT04 was prepared by mixing 90%> Matt Glaze Frit (Low Temperature), and 10%> washed china clay for a batch of 2 kg. The resulting mixture was wet ground with 33%o demineralized water in an alumina lined mill. The final glaze residue was 8.6%o on a #350 mesh. The resulting glaze was applied on a pre-engobed green tile using a glaze strip applicator. The glaze thickness was 0.5mm. The tile sample was dried in an industrial oven and fired at 1120C. The fired surface of the glaze was matt. The fired tile was cut into six pieces of size 100mm x 100mm and tested for antimicrobial and antiviral efficacy. The antibacterial efficacy and antiviral efficacy were reported at 50.92%> and 46.78%> respectively.

The embodiments relating to the active material treated glazes of the present invention are further described with the help of the following examples.
Example 17
In one such embodiment of the present invention, antimicrobial test AMI and AM2 was conducted by preparing a glaze composition GC1 and GC2 with 87% & 84%) Glossy Glaze Frit (Low Temperature), 3% & 6% of the previously prepared active material Al respectively, and 10%> of washed china clay for a batch of 5 kg. The resulting mixture was wet ground with 37% demineralized water in an alumina lined mill. The final glaze residue was 9.5% on a #350 mesh. The resulting glaze was applied on a pre-engobed green tile using a glaze applicator, which resembles the Bell application. The tile thus coated had a glaze thickness of 0.55mm, was dried in an industrial oven and fired at 1150C (for AMI) and at 1160C (for AM2). The fired surface of the glaze was glossy. The fired tile was cut into six pieces of size 100mm x 100mm and tested for antimicrobial and antiviral efficacy as per the protocol detailed in the prior section. The antibacterial efficacy and antiviral efficacy for test AMI were reported as 98.26%> and 96.7% respectively. The antibacterial efficacy and antiviral efficacy for test AM2 were reported as 97.2% and 96.4% respectively.
Example 18
In another embodiment of the present invention, antimicrobial test AM3 was conducted preparing a treated glaze composition GC3 mixing 3% of active material A2 is mixed with 87% of Satin Matt Glaze Frit (High Temperature), and 10%) china clay to prepare a dry stock of 3kg. This was ground in presence of sufficient demineralized water, binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 9% on a 350 mesh. This residue is important for achieving the right surface texture and the other glaze properties. The resultant glaze was applied through a strip applicator on a dried and engobed

green ceramic tile. The glaze coated ceramic tile was dried at 225C and then fired at 1180C in a roller hearth kiln following the process flow chart as detailed in Figure 2. After the firing process is complete, the tiles were rectified, if required, for achieving the smooth edge surface. The tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial efficacy as per the test standard JIS Z 2801 and the antiviral efficacy as per the test standard ISO 21702. The antibacterial efficacy and antiviral efficacy for test AM3 were reported as 98.6% and 99.12%> respectively.
Example 19
In yet another embodiment of the present invention, antimicrobial test AM4 was conducted preparing a treated glaze composition GC4 by mixing 6%> of active material A2 with 84% of Glossy Glaze Frit (Low Temperature), and 10%> china clay to prepare a dry stock of 3kg. This was wet milled with sufficient demineralized water, binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 8.1%> on a 350 mesh. This residue is important for achieving the right surface texture and the other glaze properties. The resultant glaze was applied through a strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1125C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial efficacy. The antibacterial efficacy and antiviral efficacy for test AM4 were reported as 98.1% and 99.08%) respectively.
Example 20
In yet another embodiment of the present invention, antimicrobial test AM5 was conducted preparing a treated glaze composition GC5 by mixing 3% of active material A3 with 87% of Matt Glaze Frit (Low Temperature), and 10% china clay to prepare a dry stock of 3.5kg. This was wet milled with sufficient demineralized

water, binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 8.6% on a 350 mesh. The resultant glaze was applied through a strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 180C and then fired at 1125C in a roller hearth kiln. The satin matt tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial and anti-viral efficacy. The antibacterial efficacy and antiviral efficacy for test AM5 were reported as 99.18% and 99.58% respectively.
Example 21
In yet another embodiment of the present invention, antimicrobial test AM6 was conducted preparing a treated glaze composition GC6 by mixing 6% of active material A3 with 84% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with sufficient demineralized water, binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 6.5% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial efficacy and antiviral efficacy. The antibacterial efficacy and antiviral efficacy for test AM6 were reported as 99.58% and 99.5% respectively.
Example 22
In yet another embodiment of the present invention, antimicrobial test AM7 was conducted preparing a treated glaze composition GC7 by mixing 3% of active material A4 with 87% of Satin Matt Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 37% demineralized water, sufficient binders and deflocculants in an alumina lined mill.

The final residue of the glaze was maintained at 8.5% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1180C in a roller hearth kiln. The satin matt tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial efficacy and antiviral efficacy. The antibacterial efficacy and antiviral efficacy for test AM7 were reported as 97.08%> and 9136% respectively.
Example 23
In yet another embodiment of the present invention, antimicrobial test AM8 was conducted preparing a treated glaze composition GC8 by mixing 6% of active material A4 with 84% of Glossy Glaze Frit (High Temperature), and 10%> china clay to prepare a dry stock of 3kg. This was wet milled with 38%> demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 6.5% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 220C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial efficacy and antiviral efficacy. The antibacterial efficacy and antiviral efficacy for test AM8 were reported as 99.2% and 99.7% respectively.
Example 24
In yet another embodiment of the present invention, antimicrobial test AM9 was conducted preparing a treated glaze composition GC9 by mixing 4% of active material A5 with 86% of Glossy Glaze Frit (Low Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 7.5% on a 350 mesh. The resultant glaze

was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 190C and then fired at 1125C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM9 were reported as 99.34% and 95.45% respectively.
Example 25
In yet another embodiment of the present invention, antimicrobial test AM10 was conducted preparing a treated glaze composition GC10 by mixing 4% of active material A6 with 86% of Glossy Glaze Frit (Low Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 7.6% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 190C and then fired at 1125C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM10 were reported as 98.34% and 88.12% respectively.
Example 26
In yet another embodiment of the present invention, antimicrobial test AMU was conducted preparing a treated glaze composition GC11 by mixing 4% of active material A7 with 86% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 7.0% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 180C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of

size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AMI 1 were reported as 60.54% and 48.9% respectively.
Example 27
In yet another embodiment of the present invention, antimicrobial test AM12 was conducted preparing a treated glaze composition GC12 by mixing 4% of active material A8 with 86% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and defiocculants in an alumina lined mill. Addition of more Cu20 is not suitable for glaze application. The final residue of the glaze was maintained at 8.0% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM 12 were reported as 98.6% and 97.24% respectively.
Example 28
In yet another embodiment of the present invention, antimicrobial test AMI 3 was conducted preparing a treated glaze composition GC13 by mixing 4% of active material A9 with 86% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and defiocculants in an alumina lined mill. The final residue of the glaze was maintained at 8.5% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 210C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM 13 were reported as 88.6% and 64.56% respectively.

Example 29
In yet another embodiment of the present invention, antimicrobial test AM14 was conducted preparing a treated glaze composition GC14 by mixing 4% of active material A10 with 86% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 36% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 8.0% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1180C in a roller hearth kiln. The glossy tile thus prepared were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM 14 were reported as 92.34% and 94.56% respectively. Example 30
In yet another embodiment of the present invention, antimicrobial test AMI 5 was conducted preparing a treated glaze composition GC15 by mixing 4% of active material All with 86% of Satin Matt Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 38% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 8.20% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 210C and then fired at 1180C in a roller hearth kiln. The resultant tile was rough in surface and was not suitable for normal use. However, the tile was characterized for antibacterial efficacy and antiviral efficacy. The tiles were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AM15 were reported as 78.54% and 65.46% respectively.
Example 31

In yet another embodiment of the present invention, antimicrobial test AMI 6 was conducted preparing a treated glaze composition GC16 by mixing 4% of active material A12 with 86% of Glossy Glaze Frit (High Temperature), and 10% china clay to prepare a dry stock of 3kg. This was wet milled with 40% demineralized water, sufficient binders and deflocculants in an alumina lined mill. The final residue of the glaze was maintained at 7.20% on a 350 mesh. The resultant glaze was applied using a glaze strip applicator on a dried and engobed green ceramic tile. The glaze coated ceramic tile was dried at 200C and then fired at 1180C in a roller hearth kiln. The resultant tile was rough in surface and was not suitable for normal use. However, the tile was characterized for antibacterial efficacy and antiviral efficacy. The tiles were cut into smaller pieces of size 100m x 100mm and tested. The antibacterial efficacy and antiviral efficacy for test AMI 6 were reported as 52.56% and 68.74% respectively.
In order to understand the implications of the active material compositions with respect to their oxide composition and particle size the results of efficacy is analyzed. The individual oxide from the active material composition is tabulated with respect to the antimicrobial tests.
Example 32
In yet another embodiment of the present invention, a pilot scale trial was conducted to further ascertain whether the results achieved in the laboratory scale can be achieved in an industrial scale. Antimicrobial test AM5 was conducted preparing a treated glaze composition GC5 by mixing 3% of previously prepared active material A3 with 87% of Matt Glaze Frit (Low Temperature), and 10% china clay to prepare a dry stock of 100 kg. This was wet milled with 38% demineralized water, sufficient binders such as 1.5% Carboxy Methyl Cellulose and sufficient deflocculant, such as 0.3% sodium try poly phosphate in an alumina lined alumina ball mill. The final residue of the glaze was maintained at 9.5% on

a 350 mesh. The resultant glaze was applied through an olnine Bell application on a pressed wall tile of size 300mm x 600mm. A set of 50 tiles were prepared in order to get sufficient tiles for testing and evaluation, and in order to evaluate all manufacturing issues that may arise due to the use of the fine precursor powders. During the glaze application, very fine bubbles were observed in the glaze tank. After adding some antifrothing agents drop by drop, it was observed that the fini bubbles reduced. The glaze coated ceramic wall tiles were dried at 180C-220C in the prekiln drier and then fired at a peak temperature of 1125C in a roller hearth kiln. The satin matt tiles thus prepared were cut into smaller pieces of size 100m x 100mm and tested for anti-bacterial and anti-viral efficacy. The antibacterial efficacy and antiviral efficacy were reported as 99.48% and 99.60% respectively.
A closer look at the results achieved in various tests reveals the following.
Effect of compositional addition level of the active microbial material precursor oxide powders
a) Only Ti02 at an addition level of 4% in the test AMU results in antibacterial efficacy and antiviral efficacy as 60.54% and 48.9% respectively. So Ti02 is not yielding good results.
b) Only Cu20 at an addition level of 4% in the test AM 12 results in antibacterial efficacy and antiviral efficacy as 98.6% and 97.24% respectively. Cu20 addition increases the antibacterial efficacy and antiviral efficacy significantly, though it fails to achieve the 99% reduction alone.
c) Only ZnO at an addition level of 4% in the test AM 9 results in antibacterial efficacy and antiviral efficacy as 99.34% and 95.45% respectively.

d) Only Glass powder mixed nano Silver (Ag) at an addition level of 4% in the test AM 10 results in antibacterial efficacy and antiviral efficacy as 98.34% and 88.12% respectively.
e) Only CuO at an addition level of 4% in the test AM 13 results in antibacterial efficacy and antiviral efficacy as 88.6% and 64.56% respectively.
f) CuO and ZnO at an addition level of 2% each in the test AM 14 results in a synergistic effect to result in antibacterial efficacy and antiviral efficacy as 92.34%) and 94.56%> respectively. It is evident that ZnO is more contributing to this property than CuO.
g) Ti02 and CU2O at an addition level of 1.5% each in the test AM 1 results in a synergistic effect compared to only Ti02 to result in antibacterial efficacy and antiviral efficacy as 98.26% and 96.7% respectively. It is evident that Q12O brings in the desired property.
h) Q12O and ZnO at an addition level of 1.5% each in the test AM 5 and 3.0%) each in the test AM 6 result in a synergistic effect compared to only only Cu20 and only ZnO. These result in antibacterial efficacy and antiviral efficacy more than 99% in each case. It is evident that an addition level of more than 1.5% each of Q12O and ZnO does not make a significant increment in bacteria and virus reduction, as already 99.5% reduction is achieved.
i) Ti02, Cu20, and ZnO at an addition level of 1.2%, 0.8%, and 0.8% in the test AM 7 result in a synergistic effect of more than 97% which is higher than when compared to only Ti02, only CU2O and only ZnO. However, at 0.9%) addition level of CU2O and ZnO, the test fails to achieve the 99% reduction level.

j) Where as, HO2, CU2O, and ZnO at an addition level of 0.6%, 1.2%, and 1.2% in the test AM3 and double of it in AM4 results in minimum of 98.1%) antibacterial efficacy, and 99.08%> antiviral efficacy.
After reviewing all the results so far, it was clearly understood that Cu20 and ZnO are producing very good antimicrobial and antiviral efficacy. In order to ascertain the exact inflection, point of the addition level of these two active materials, two more experiments are designed. These are detailed in the tests AMI7 and AM 18 were conducted. In both the tests the active precursor powder composition A3 is taken and 1,5% and 7% are added respectively to the glossy glaze of 88.5%) and 83%> respectively. These were processed and tiles were applied with these glazes, The previously engobed, and glazed tile thus made were fired at 1125C in a rapid fast firing roller hearth kiln. The resultant fired tile of the test AM 17 was found to be glossy and smooth in texture. The antimicrobial and antiviral efficacy were found to be at 72.54%> and 76.44%, However, the resultant fired tile of the test AMI 8 was found to be very rough in texture and showed crawling on surface. The antimicrobial and antiviral efficacy were found to be at 70.46% and 76.6%,
After review of all the results, it was evident that the combination of CU2O and ZnO active precursor powder does not yield the desired 99% antimicrobial efficacy and lower level of addition and as well as in higher level of addition at 7%>. At higher level of addition, the efficacy actually reduces drastically. This is because the roughness of the surface brings in the additional disadvantages, and it loses the antimicrobial and antiviral efficacy. Therefore, at higher level of addition of these precursor oxides are not feasible for glazes used in rapid fast firing applications.

Effect of particle size of the active Microbial Material
A few tests were also conducted to understand the effect of particle size of the active materials.
All the three active oxide material, such as, TiCh, CU2O, and ZnO are used in the tests AM7, AM8, AM15 and AM16 at various addition level from 3% to 6%. The particle size of the active material oxides employed in tests AM7 and AM8 is 98% below in 45 micron and in tests AM15 and AM16 is 98% below in 90 microns. In the later two tests, the particle size was kept higher to evaluate its effect of the antibacterial and antiviral efficacy. It was observed that at higher particle sizes, in tests AM15 and AM16, the antibacterial and antiviral efficacy does not cross beyond 78.54% and 68.74%). The surface of the tile was also very rough and was found unusable in any practical purpose.

claim:

1. An antimicrobial and antiviral ceramic tile, comprising
an engobe coated green ceramic tiles;
a glaze layer applied on the engobe coated green ceramic tiles wherein the said glaze layer comprising 3% - 6% precursor powders, 84% - 87% frit and 10 % china clay;
wherein said precursor powder comprising 20% to 100% Ti02, 30% to 100% Cu20, 30% to 100% ZnO, 100% Ag Nano or 50% to 100% CuO alone or in combination thereof wherein the precursor powder particle is kept below 45 microns - 90 microns
2. The antimicrobial and antiviral ceramic tile as claimed in claim 1, wherein frit is selected from the group comprising Glossy Glaze Frit (Low temp) Satin Matt Glaze Frit (High Temp) Glossy Glaze Frit (High temp) Matt Glaze Frit (Low Temp) etc.
3. The antimicrobial and antiviral ceramic tile as claimed in claim 2, wherein the frits contain set of oxides from the group consisting of of Si02, AI2O3, CaO, MgO, Na20, K20, Ba203, ZnO, B2O3, and Zr02.
4. The antimicrobial and antiviral ceramic tile as claimed in claim 1, wherein the precursor powder preferably comprising 50% red cuprous oxide (Cu20) and 50% zinc oxide (ZnO).
5. The antimicrobial and antiviral ceramic tile as claimed in claim 4, wherein the precursor powder is preferably mixed and ground to a particle size of 98% smaller than 45 microns.

6. The antimicrobial and antiviral ceramic tile as claimed in claim 5, wherein the size of 98% precursor powder particle is below 45 microns and 99.5% precursor powder particle is below 50 microns.
7. The antimicrobial and antiviral ceramic tile as claimed in claim 1, wherein said glaze layer preferably comprising 1.5% CU2O, 1.5% ZnO, 87% Matt Glaze Frit (Low Temp) and 10 % china clay.
8. The antimicrobial and antiviral ceramic tile as claimed in claim 1, wherein ceramic tile comprising of glaze composition of claim 7 shows antibacterial efficacy and antiviral efficacy more than 99%.
9. A method for preparing ceramic tile having increased antimicrobial and antiviral activities, comprising
providing a glazed composition comprising 84% - 87% frit and 10 % china clay, and contacting the said glazed composition at a temperature ranging from 1050C to 1250C, with a precursor powder in order to prepare the glaze followed by applying the said glaze on an existed engobe coated green ceramic tiles and firing at temperature in the range of 1125C to 1180C to prepare the said ceramic tile having 96.4% - 99.58% antimicrobial and antiviral activities,
wherein the precursor powder comprising 20% to 100% Ti02, 30% to 100% Cu20, 30% to 100% ZnO, 100% Ag Nano or 50% to 100% CuO alone or in combination thereof ((wherein particle size of the precursor powders is kept below 45 microns - 90 microns by wet milling in a suitable alumina lined ball mill, and
wherein the said glaze comprising 3% - 6% precursor powders, 84% -87% frit and 10 % china clay.

10. The method as claimed in claim 9, wherein said method preferably, comprising
preparing glaze composition by mixing 3% of precursor powder with 87% of Matt Glaze Frit (Low Temperature), and 10% china clay followed by maintaining the final residue of the glaze was at 8.6% on a 350 mesh wherein precursor powder contains 1.5% of CU2O, 1.5 % ZnO;
applying the glaze of step (1) on dried engobed green ceramic tile, followed by drying at 180C and then fired at 1125C
wherein said glazed ceramic tile shows antibacterial efficacy and antiviral efficacy more than 99%.