WO2002021970A1

WO2002021970A1 - Cleaning device and associated method

Info

Publication number: WO2002021970A1
Application number: PCT/US2001/028853
Authority: WO
Inventors: Ashok V. Joshi
Original assignee: Ceramatec, Inc.
Priority date: 2000-09-15
Filing date: 2001-09-14
Publication date: 2002-03-21
Also published as: AU2001290975A1

Abstract

A cleaning, sanitizing (1) and/or disinfecting device for treatment of a surface with a photocatalytically activatable material comprising: an applicator, wherein the applicator is configured for application to a surface; a light source, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto; and means for powering the light source.

Description

TITLE OF THE INVENTION

CLEANING DEVICE AND ASSOCIATED METHOD BACKGROUND OF THE INVENTION

1. Field of the Invention The present invention relates in general to cleaning devices, and more particularly, to a cleaning, sanitizing and/or disinfecting device having an applicator and a light source, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto. When activated, the photocatalytic material serves to purify, disinfect, sanitize, and/or otherwise beneficially effect an associated surface.

2. Background Art

Research associated with the use of photocatalytic materials has been explored in recent years. In particular, Dr. Akira Fujishima et al., recently published "TiO, Photocatalysis Fundamentals and Applications" (1997), which discloses the use of photocatalytic TiO, for numerous applications, including cleaning various surfaces.

While cleaning surfaces with photocatalytically activated materials has been recently explored, there remains a desire to incorporate such technology into devices, which, themselves are capable of internally activating such photocatalytic materials without the use of expensive, and often times large, activating light sources. It is therefore an object of the present invention to provide a device which overcomes the present detriments and/or complications associated with utilizing photocatalytic materials. These and other objects of the present invention will become apparent in light of the present specification, claims, and drawings.

SUMMARY OF THE INVENTION

The present invention is directed to a cleaning, sanitizing and/or disinfecting device for treatment of a surface with a photocatalytically activatable material comprising: (a) an applicator, wherein the applicator is configured for application to a surface; (b) a light source, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto; and (c) means for powering the light source.

The photocatalytically activatable material comprises a semi-conductive material having a band gap of approximately 1 to approximately 4 eV. In a preferred embodiment of the invention, the photocatalytically activatable material includes TiO,, although other semi-conductive materials, such as those listed in Table I (found later in this document) which release hydroxide ions upon exposure to a light source are also contemplated for use. In such an embodiment, the photocatalytically activatable material includes TiO₂ based solid solutions and compounds having a total electron volt band gap less than the electron volt band gap of TiO₂ Indeed, the TiO₂ can be used in combination with various peroxides, superperoxides, permanganates, iodates, chlorides and halides. Some examples of contemplated photocatalytically activatable materials include, but not are limited to: TiO₂, SrTiO₃, BaTiO₃, CaTiO₃, KTaO₃, Pb(La)TiO₃, Pb(Zr)TiO₃, Fe₂TiO₅, FeNbO₄, Fe₂O₃, WO₃, SnO₂, GaP, CdFe₂O₄, PbFe₁₂O₁₉, Pb₄Ti₃WO₁₃, Hg₂Ta₂O₇, Hg₂Nb₂O₇, ZrO₂, T--A, Nb₂O₅, Sr,Nb₂O₇, Fe₂O₃/TiO₂, In₂O₃,

NaNbO₃, CdTe, GaSe, CuInS,, InSe, BaSrNb₄O₁₂, BiOC„ Bi₄Ti₃O₁₂, Bi₂O₂, Bi₂WO₆, NiNb₂O₆, MgNb₂O₆, Ti ₉Nb_αιO₂, YfeO₃. In one preferred embodiment of the present invention, the photocatalytically activatable material is applied to at least a portion of the applicator. It is also contemplated that the material be integrally associated with the applicator. Alternatively, or in addition to, the photocatalytic material may be applied directly on to the surface to be cleaned, sanitized and/or disinfected.

In yet another preferred embodiment, the applicator comprises a brush having bristles, and the photocatalytically activatable material is associated with the bristles of the brush. It is contemplated that the brush comprise a tooth brush, hair brush, fabric cleaning brush or other surface cleaning, sanitizing and/or disinfecting type brush. In a preferred embodiment, the applicator may comprise a patch, or the like, for positioning over tissue of an animal or a human, wherein such tissue requires cleaning, sanitizing, disinfecting or healing.

In still another preferred embodiment, the applicator may comprise dusting pads, broom bristles, mop heads, vacuum cleaner rollers and sweepers, cleaning cloths, towels and sponges, each being associated with the light source for activating the photocatalytically activatable material. The photocatalytically activatable material may be directly associated with the applicator and/or applied directly to the surface to be cleaned.

In a preferred embodiment of the invention, the light source consists of a wavelength less than approximately 450 nanometers. Indeed, the light source may comprise one or more light emitting diodes, such as gallium based light emitting diodes. It is also contemplated that the present device comprises means for powering the light source. The powering means can be AC current and/or DC current (i.e., a primary or secondary electrochemical cell).

The present invention is also directed to a method of cleaning, sanitizing and/or disinfecting a surface comprising the steps of a) providing a device including an applicator, wherein the applicator is configured for application to a surface, a light source, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto, and means for powering the light source; b) associating a photocatalytically activatable material with the applicator; c) applying the applicator to a surface to be cleaned; d) activating the light source; e) initiating photocatalysis of the photocatalytically activatable material; and f) at least one of cleaning, sanitizing and/or disinfecting the surface with the photocatalytically activated material.

In a preferred embodiment of the method, the step of associating a photocatalytically activatable material comprises the step of integrally associating the material with the applicator. Alternatively, or in addition thereto, the photocatalytically activatable material may be directly applied to the surface to be cleaned, sanitized and/or disinfected prior to the step of applying the applicator to the surface to be cleaned, sanitized and/or disinfected.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the drawings wherein:

Fig. 1 of the drawings is a schematic representation of a first embodiment of a device in accordance with the present invention; Fig. 2 of the drawings is a schematic representation of a second embodiment of a device in accordance with the present invention;

Fig. 3 of the drawings is a schematic representation of a third embodiment of a device in accordance with the present invention;

Fig. 4 of the drawings is a schematic representation of a fourth embodiment of a device in accordance with the present invention;

Fig. 5 of the drawings is a schematic representation of a fifth embodiment of a device in accordance with the present invention;

Fig. 6 of the drawings is a schematic representation of a sixth embodiment of a device in accordance with the present invention; and Fig. 7 of the drawings is a schematic representation of a seventh embodiment of a device in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiment in many different forms, there is shown in the drawings and described herein in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the invention to the embodiments illustrated.

It will be understood that like or analogous elements and/or components, referred to herein, are identified throughout the drawings by like reference characters.

Referring now to the drawings and to Fig. 1 in particular, device 10 is shown in a first embodiment as generally comprising applicator 12, light source 14, and means 16 for powering light source 14. As will be discussed in greater detail below, device 10 is configured for treatment of a surface with a photocatalytically activatable material. Such a surface may include, for example, a floor, a table top, a counter top, a tooth, etc. As will also be discussed in greater detail below, device 10 is capable of killing/neutralizing contaminants, such as microorganisms, germs, bacteria, viruses, undesirable chemicals and/or compounds, etc.

While device 10 has been shown in Fig. 1 as being substantially rectangular, numerous other geometric configurations are likewise contemplated for use including generally circular, generally elliptical, generally square, generally triangular, generally polygonal, and generally arbitrary. For purposes of the present disclosure, applicator 12 is configured for application to surface 18, and may comprise any one of a number of materials including a sponge (Fig. 3), a brush (Fig. 1), a vacuum cleaner roller (Fig. 6), a plurality of bristles (Figs. 1, 4 and 6), a cloth material (Fig. 5), a medical patch (Fig. 7) -just to name a few. In a preferred embodiment of the invention, photocatalytically activatable material

20 may be associated directly with applicator 12. For example, photocatalytically activatable material 20 may be applied onto at least a portion of the surface of applicator 12. Additionally, or alternatively, photocatalytically activatable material 20 may likewise be coated onto, or chemically foπmilated as part of applicator 12 itself. For example, the procedure for coating the bristles of a brush, nylon fibers, polypropylene fibers, or any inorganic or organic material fiber is explained as follows. First, approximately 1% to 30% TiO, of an anatase crystal structure (or any other semiconductor material) is mixed with any soap composition (approximately 0.1 to 0.5% of polyoxyethylene lauryl ether) and a paste/paint is made by adding water . The paste is then sprayed, coated (or dipped) on to fibers or bristles. After coating, spraying or dipping the fibers with the TiO, paint, the fibers are dried either at room temperature or at elevated temperatures up to 800°C, depending upon the material. For example, polymeric materials coated with TiO, should be dried at between ambient to 100°C for anywhere between 30 minutes to 2 hours. Ceramic or metal fibers can be dried at any where between 250° to 800°C for 10 minutes to an hour.

As will also be explained, the photocatalytically activatable material may comprise a powder or liquid which can be separately applied to the surface to be cleaned, sanitized and/or disinfected. In such an embodiment, activation of the photocatalytically activatable material, and thus release of its purifying properties, will occur upon exposure from the light source integrated with an associated applicator, such as applicator 12.

In accordance with the present invention, photocatalytically activatable material

20 may comprise any one of a number of semi-conductive materials, including, but not limited to substantially pure TiO,, and the semiconductive materials listed in Table I hereinbelow:

TABLE I PHOTOCATALYTIC MATERIALS

TiO, and Titanates

Fe,O₃ and compounds of Fe,0₃ and other oxides

Silver and Copper Oxides, halides and chalcogenides

Vanadium pentoxide and validates

Tin oxides and stannates

NbO, and Niobates

TiO, and NbO2 solid solutions

Bi,O₃ and bismuth chalcogenides

Silicon and Germanium doped with p-type and n-type impurities

P-N junctions of semiconductors, such as Si, ZnS, GaAs, etc.

Photovoltaic materials, such as silicon, Ge, InP, ZnP

Zinc chalcogenides and Zn oxides and Zn phosphides.

It is also contemplated that such semi-conductive material comprise solid solutions and compounds having a total electron volt band gap less than 5 ev. Examples include, but are not limited to, TiO, and SrTiO₃. Furthermore, such semi-conductive material can be made in combination with peroxides, such as AgO, SnO, CuO, superperoxides, such as BaO₂ and CaO,; permanganates, such as KMnO₄,; iodates, such as NaIO₃; and chlorides and halides, such as various metal iodides and chlorides. Regardless, it will be understood that all preferred semi-conductive materials will exhibit a band gap of approximately 1 to approximately 4 eV so that the particular material can be readily activated by, for example, a semi-conductive material light activating source, such as a light emitting diode or an array thereof. Examples of acceptable LED sources are commercially available from NICHIA America Corporation in San Jose, California.

As is shown in Fig. 1, light source 14 is preferably positioned between applicator 12 and light source powering means 16. It will be understood, however, that light source 14 can be positioned any one of a number of ways - so long as light source 14 is sufficiently proximate to photocatalytically activatable material 20 to, in turn, enable activation of the same for cleaning/purifying/disinfecting purposes. It is also contemplated that the light from light source can be transported to photocatalytically available material via polymeric or glass fibers in order to enable activation of the photocatalytic material for cleaning/purifying/disinfecting purposes. For example, in a brush, it is possible to make bristles from fiber optics for transfer of light from a light source located at a distance (say from an associated brush handle). The fibers would then transport the light from the light source to the photocatalytic material, which is in the proximity of the surface to be cleaned.

For purposes of the present disclosure, light source 14 consists primarily of a wavelength less than approximately 600 nanometers. In a preferred embodiment of the present invention, light source 14 may comprise one or more light emitting diodes, and, preferably gallium based light emitting diodes. As will be readily understood, the amount/array of lighting will be dependent upon the size of the particular applicator and the intended area to be cleaned at each point of use. For example, a tooth brush may require only one light, while a hair brash or dusting pad may require 3 or more.

Light source powering means 16 is preferably adjacent light source 14 and may comprise, for example, AC current and/or DC current. Preferred sources of DC current include primary and/or secondary electrochemical cells. While light source powering means 16 has been disclosed as being adjacent light source 14, it will be understood that conventional electrical conduit/power cords may be used if the configuration of the device necessitates a more remote displacement. In addition, it is contemplated that a conventional switch be utilized in association with the power source for selectively turning the power source "on" or "off."

As is shown in Fig. 2, cleaning device 10 (configured as a dental toothbrush) comprises base 17 having a stem portion 19 and a head portion 21. Applicator 12 is incorporated into head portion 21 of base 17, as is light source 14. Light source powering means 16 which, in a preferred embodiment comprises a conventional battery, is controllably operated by switch 16'. Although the switch may be of the conventional slide type, other conventional switches such as internal button switches, are also contemplated for use. Although such a device has been described for use as a tooth brash, it is also contemplated that substantially the same configuration be incorporated for use as another type of brush - such as a hair brush, a brash used for cleaning furniture, automobile interiors, clothing, countertops etc.

Various alternative preferred embodiments of the present invention are shown in Figs. 3-7. In each of such embodiments, cleaning-type devices are shown for illustrative purposes only. All of such embodiments incorporate the same basic structural components as those identified with respect to Fig. 1 and Fig. 2. Accordingly, where applicable, like reference numerals will be used for like or analogous elements and/or components. Device 30 is shown in Fig. 3 as comprising a sponge, or surface wiping block.

Sponge 30 includes light source powering means 16 and light source 14 formed into the base/palm portion of the sponge. Photocatalytically activatable material 20 is shown as being impregnated throughout absorbent portion 75 of the sponge. Alternatively, photocatalytically activatable material 75' can be applied to surface 77 of the sponge upon manufacture, or, by a user equipped with additional material for on site application.

It is likewise contemplated for this preferred embodiment, as well as the other preferred embodiments described herein, that photocatalytically activatable material be formulated into a paste, liquid or powder, among others, for application directly onto the surface to be cleaned/purified — followed by association with the particular applicator/light source device.

Device 40 is shown in Fig. 4 as comprising a broom with bristles 85 (or, alternatively, a mop head). The broom includes handle 86 which incorporates light source powering means 16 (battery) therein. As can be seen, a conventional slide "on/off switch 16' is positioned on the handle. Light source 14 is positioned at bottom 87 of handle 86, and photocatalytically activatable material 20 is impregnated, coated or chemically formed in, on or with the bristles. Alternatively, or in addition, the photocatalytically activatable material may be applied directly to the area to be swept/mopped.

Another preferred embodiment of device 50 is shown in Fig. 5 as comprising a floor dusting pad/broom. As in the broom embodiment of Fig. 4, the dusting pad includes a handle 86 with powering means 16 and switch 16' associated therewith. Again, light source 14 may be positioned at bottom 87 of the handle. Instead of bristles or a mop head, device 50 includes a dusting pad 90, typically fabricated from conventional static material. Although conventional static material attracts and picks up dust by static electricity, it does not aide in the destruction of germs and bacteria. For purposes of disinfecting the area being dusted, the present invention/embodiment associates photocatalytically activatable material 20 in or with static dust pad 90.

In yet another preferred embodiment, device 60 is shown, in partial cross section in Fig. 6, as a vacuum cleaner wherein light source 14 is operatively positioned adjacent the vacuum rollers/brushes 95. Photocatalytically activatable material 20 may be associated with the rollers/brushes in a manner as previously described. It is also contemplated that, in such an embodiment, photocatalytically activatable material 20' can be applied directly onto, or formulated with or into carpet 96, or other surface. Although not shown, the power source can be a batteiy for portable usage, or, it can comprise a conventional power cord for use with an A.C. current typically found in a home.

In still another preferred embodiment, device 70 is shown in Fig. 7 as comprising a wound or tissue treating device. Device 70 includes patch ("applicator") 75 which can be applied, for example, onto the skin, or other tissues of an animal or human for treatment thereto. Photocatalytically activatable material 20 is either applied directly onto the tissue (such as in a cream, paste or liquid form) or, is directly associated with patch 75. Light source 14 can be integrally formed in the patch or associated by, for example, fiber optic conduits.

In operation, whether it be use of a brush, a sponge, vacuum cleaner, broom dusting pad, or a tissue associated patch, a user merely places the desired applicator adjacent the surface desired to be cleansed/purified. For example, and for illustrative purposes only, if the surface to be cleaned is the teeth of an individual, then, toothbrash 20 (Fig. 2) is placed in a person's mouth so that the brush bristles (applicator) 12 comes into contact with the teeth. Either before or after teeth brushing commences, switch 16' is adjusted to the "on" position to, in turn, activate light source 14. In an embodiment where photocatalytically activatable material is directly associated with the brash bristles (e.g. coated, impregnated, chemically formulated therewith), a user would simply engage in a conventional teeth brushing procedure. As the light from light source 14 propogates into contact with the photocatalytically activatable material, and, due to the previously described electron volt band gap of the light source, the semi-conductive photocatalytically activatable material releases hydroxide ions. As is well know, hydroxide ions actually kill, or neutralize, bacteria/germs. Accordingly, the treated surface, as a result of the released hydroxide ions becomes cleansed and disinfected.

In addition, and/or as an alternative to initially associating the photocatalytically activatable material with the particular applicator, a user can apply the material directly onto the surface to be treated. For example, a separate toothpaste can easily be formulated to include photocatalytically activatable material therein. Such a formulation can comprise the following constituents and ranges, wherein the composition is expressed as wt %:

- TiO₂ or other photocatalytic semiconductive material from 2% to 50%;

- 10% to 70%) of a humectant, such as sorbitol, glycerine, xylitor, polyethelyne glycol, or mixtures of these;

- Flavorings such as mint from 1% to 3%;

- Binders from 0.2 to 2%;

- Whiteners, such as bleach from 0.5 to 3%;

- Fluorides from 0.1 to 0.5%; - Sodium lauryl sulphate 1% to 3%; and

- Water from 10% to 50%.

A typical toothpaste composition may contain

Photocatalytic TiO₂ - 20%; Sorbitol (70% solution) - 40%;

Polyethylene glycol - 5%;

Flavorings - 1.5%;

Binder - 1%;

Whitener- 1%; Sodium Fluoride - 0.2%; and

Sodium Lauryl sulphate 1.8%.

In such an embodiment, the applicator, such as a toothbrush or vacuum cleaner, among others, would include at least a light source and an associated light source powering means. The photocatalytically activatable material may then be directly applied (in liquid or powder form, for example) onto a surface, such as a table top, kitchen floor, or even carpet. After the material is applied, such as by spraying the liquid or sprinkling the powder, the desired applicator (i.e. sponge, broom, dust mop, or vacuum cleaner) incorporating at least an appropriate light source and associated light source powering means, is brought into operative positioning relative to the area/surface to be cleaned. As yet another alternative, it is further contemplated that various surfaces, such as countertops, hard floors, carpeting and clothing, among others be fabricated with photocatalytically activatable material integrally foπned therewith. In such an embodiment, applicators contemplated by the present invention, can be used for cleaning/purifying such surfaces/material with or without additional photocatalytically activatable material directly applied to the respective applicators.

The foregoing description merely explains and illustrates the invention and the invention is not limited thereto except insofar as the appended claims are so limited, as those skilled in the art who have the disclosure before them will be able to make modifications without departing the scope of the invention.

Claims

WHAT IS CLAIMED IS:

1. A cleaning, sanitizing and/or disinfecting device for treatment of a surface with a photocatalytically activatable material, comprising: - an applicator; a photocatalytically activatable material; and, a light source associated with the applicator for activating the photocatalytically activatable material.

2. The device according to claim 1, wherein the photocatalytically activatable material comprises a semi-conductive material.

3. The device according to claim 1, wherein the photocatalytically activatable material comprises a semi-conductive material having a band gap of approximately 0.5 to approximately 5 eV.

4. The device according to claim 2, wherein the photocatalytically activatable material includes semiconductive materials listed in Table I.

5. The device according to claim 2, wherein the photocatalytically activatable material includes TiO₂ based solid solutions and compounds having a total electron volt band gap less than the electron volt band gap of TiO,

6. The device according to claim 2, wherein the photocatalytically activatable material includes TiO, in combination with one or more of the groups comprising peroxides, superperoxides, permanganates, iodates, chlorides and halides.

7. The device according to claim 1, wherein the photocatalytically activatable material is applied to at least a portion of the applicator.

8. The device according to claim 1, wherein the photocatalytically activatable material is integrally associated with the applicator.

9. The device according to claim 1 wherein the applicator comprises a brush havin bristles and the light source is associated therewith.

10. The device according to claim 9 wherein the photocatalytically activatable material is applied to the bristles of the brush.

11. The device according to claim 10 wherein the brush comprises a tooth brush.

12. The device according to claim 11 wherein the light source is associated with the bristles of the brush.

13. The device according to claim 1 wherein the applicator is selected from the group comprising dusting pads, broom bristles, mop heads and vacuum cleaner rollers and sweepers, each being associated with the light source for activating the photocatalytically activatable material.

14. The device according to claim 13 wherein the photocatalytically activatable material is associated with a respective one of the dusting pads, broom bristles, mop heads and vacuum cleaner rollers and sweepers.

15. The device according to claim 1 wherein the applicator is selected from the group comprising cleaning cloths, towels and sponges, each being associated with the light source for activating the photocatalytically activatable material.

16. The device according to claim 15 wherein the photocatalytically activatable material is associated with a respective one of the cleaning cloths, towels and sponges,

17. The device according to claim 1, wherein the light source consists primarily of a wavelength less than approximately 600 nanometers.

18. The device according to claim 1, wherein the light source comprises one or more light emitting diodes.

19. The device according to claim 18, wherein the light source comprises one or more gallium based light emitting diodes.

20. The device according to claim 1, further comprising means for powering the light source.

21. The device according to claim 20 wherein the powering means comprises one of AC current and DC current.

22. The device according to claim 21, wherein the powering means comprises a primary or secondary electrochemical cell.

23. The device according to claim 1, wherein the applicator comprises a patch for positioning adjacent an area of human or animal tissue requiring cleaning, sanitizing and/or disinfecting.

24. A cleaning, sanitizing and/or disinfecting device for treatment of a surface with a photocatalytically activatable material, comprising:

- a base having a head portion; - an applicator incorporated into the head portion of the base, wherein the applicator is configured for application to a surface;

- a light source incorporated into the head portion of the base, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto; and

- means for powering the light source associated with the base.

25. A method of cleaning, sanitizing and/or disinfecting a surface comprising the steps of:

- providing a cleaning device including an applicator, wherein the applicator is configured for application to a surface, a light source, wherein the light source is capable of activating a photocatalytically activatable material in close proximity thereto, and means for powering the light source;

- associating a photocatalytically activatable material with the applicator;

- applying the applicator to a surface to be cleaned

- activating the light source;

- initiating photocatalysis of the photocatalytically activatable material; and - at least one of cleaning, sanitizing and/or disinfecting the surface with the photocatalytically activated material.

26. The method according to claim 25 wherein the step of associating a photocatalytically activatable material comprises the step of integrally associating the material with the applicator.

27. The method according to claim 26 wherein the step of associating a photocatalytically activatable material comprises the step of applying the photocatalytically activatable material to the surface to be cleaned prior to the step of applying the applicator to the surface to be cleaned, sanitized and/or disinfected.