DESC:FIELD OF THE INVENTION:
The present invention relates to a non-woven material having antimicrobial properties and a method for manufacturing the same. Particularly, the present invention provides a method for manufacturing a non-woven material impregnated with metal loaded resin for optimum antimicrobial efficiency. The present invention also relates to an antimicrobial cooling pad manufactured using the non-woven material as described above.

BACKGROUND OF THE INVENTION:
Multiple studies highlight that air-cooling systems happen to be breeding grounds for bacteria and therefore underline the importance of cleaning and replacing cooling pads, filters, and the like, which harbor optimal conditions for such bacteria.

In the absence of frequent cleaning, cooling pads and filters become rich in bacterial growth and when air passes through them, the bacteria are carried straight into the air infecting people that breathe around such coolers. This most often occurs when the user switches on the cooling system, it is the first blow of air that is most contaminated with harmful microbes and is known to result in allergies, cold and other microorganism related illnesses/diseases.

Further, microbes produce unpleasant odors, cause discoloration of surfaces, create biofouling and produce mildew causing various health Problems.

Microorganisms like bacteria,fungi, viruses, grows on moist surfaces and breed multiple times every twenty minutes, on an average. Cleaning the cooling pads as frequently is most impractical, if not impossible. It is for this reason that many efforts have been made to solve the problem of contamination related to cooling systems.
Considering the importance of evaporative coolers and the high demand of the same, multiple efforts have been made in the field towards evolving cooling pads which are the most integral parts of coolers. One such example is the US Patent numbered US 4031180 A, which discloses water evaporative cooling systems and related cooling pads. However, it fails to disclose any antimicrobial features incorporated in the cooling pad.
Other inventions disclose cooling systems having chemicals as disinfectants. However, these chemicals are harmful to the lungs and are not advisable to be used especially in environments meant for children and elderly.
As disclosed above, there is a requirement for a cooling pad having antimicrobial properties, which is safe for all users. Therefore, there is a need to solve at least one of the problems proposed above.

SUMMARY OF THE INVENTION

An aspect of the present invention discloses a method for manufacturing a non-woven material for a cooling pad, the method comprising at least the following steps:
a. applying a resin on at least one surface of the non-woven material; and
b. Physically dispersing photochromatically activable metal oxide nanoparticles on the surface(s).

Another aspect of the present invention discloses a non-woven materialfor a cooling pad comprising:
a resin applied on at least one surface of the non-woven material; and
photochromatically activable metal oxide nanoparticles physically dispersed on the surface.

Yet another aspect of the present invention discloses a cooling pad, comprising:
a plurality of non-woven materialstacked to form the cooling pad; wherein the non-woven materialis impregnated with photochromatically activable metal oxide and coated with PF resin.

BRIEF DESCRIPTION OF DRAWINGS
Reference will be made to embodiments of the invention, example of which may be illustrated in the accompanying figure(s). These figure(s) are intended to be illustrative, not limiting. Although the invention is generally described in the context of these embodiments, it should be understood that it is not intended to limit the scope of the invention to these particular embodiments.
Figure 1 shows dual sheets of non-woven material, impregnated with metal loaded resin according to an embodiment of the present invention;
Figure 2 shows a cooling pad made with the non-woven material of the present invention, according to an embodiment of the present invention

DETAILED DESCRIPTION OF THE INVENTION
Various embodiments of the present invention provide a non-woven material for cooling pads and a method for making the same. Wherein, said non-woven material is impregnated with metal loaded PF resin having antimicrobial properties.

An embodiment of the present invention discloses a method for manufacturing a non-woven material (100, 200 of Fig. 1 & Fig. 2) for a cooling pad
(200A of Fig. 2), the method comprising steps of:
a. applying a resin on the surface(s) (110, 210 of Fig. 1 & Fig. 2) of the non-woven material(100, 200 of Fig. 1 & Fig. 2); and
b. physically dispersing photochromatically activable metal oxide nanoparticles (120, 220 of Fig. 1 &Fig. 2) on the surface(s) (110, 210 of Fig. 1 & Fig. 2).
In an embodiment of the present invention, the steps of applying resin and physically dispersing the photochromatically activable metal oxide nanoparticles (120, 220) on the surface(s) (110, 210) include a multi-step thermal cross-linking technique as follows:
a. dispersing a metal particulate in a water-soluble PF resin for forming a metal impregnated resin;
b. dip coating the non-woven material in the metal impregnated resin;
c. primary thermal cross-linking of the metal impregnated resin by heating roller(s) between 150°C and 160°C;
d. cutting and corrugating non-woven material at an angle of 45°/45° for forming a sheet of corrugated non-woven material;
e. heating the sheet in conveyor heating chamber between 160°C and 180°C for a secondary thermal cross-linking of the metal impregnated resin;
f. applying adhesive on a plurality of sheets and stacking the sheets for forming the cooling pad;
g. heating the cooling pad between 200°C and 220°C for further adhesion and a tertiary thermal cross-linking; and
h. cutting the sheets at pre-determined dimension

Wherein the resin used is preferably but not limited to a water-soluble PF resin; and wherein, the composition of phenolic resin in water is 1:3 to which metal particulates are dispersed and hand blended; the metal particulates are selected from but not limited to silver particles, Zinc Pyrothione, or such other metal(s) or metal complex(s); the thermal crosslink of said PF resin is carried out in multiple stages of curing at regular intervals to ensure maximum degree of cross-linking. This multi-stage cross-linking enables uniform distribution and fixing of the metal nano-particulates across the PF resin cross-linkage, enabling optimum antimicrobial efficiency.

The adhesive used may be selected from any industrially acceptable glue.

After the second step of thermal cross-linkage, the fluted and corrugated non-woven material is stacked in the range of 50-100 sheets to form a honeycomb structure.

In an embodiment of the present invention, the cooling pad is comprised of non-woven material having a honeycomb structure and anti-microbial properties capable of killing up to 99% microbes passing through the cooling pad.

In a further embodiment of the present invention, the step of physically dispersing the photochromatically activable metal oxide nanoparticles (120, 220) on the surface(s) (110, 210) comprises adding at least one olfactory indicator including fragrant essential oil(s), with the photochromatically activable metal oxide nanoparticles (120, 220).
Wherein, the amount of olfactory indicator mixed is directly proportional to the amount of photochromatically activable metal oxide nanoparticles.Such that as the odor of the olfactory indicator depletes the expiry of the antimicrobial effect of the photochromatically activable metal oxide nanoparticles is indicated. Thus, by means of the olfactory indicator, the user is informed / indicated of the life of the antimicrobial cooling pad and thus the user may replace the expired cooling pad with a new one at the correct time period, enabling a consistently safe environment and overcoming the shortcoming of frequently having to service / clean the cooling system.
The olfactory indicator including fragrant essential oil(s), may be selected from but not limited to Balsam of Peru; Eucalyptus oil; Lavender oil; Rose oil.
In an embodiment of the present invention, a method for constructing an antimicrobial honeycomb cooling pad comprises at least the steps of:
• Dispersion of metal particulate in water soluble PF resin;
• Dip coating of non-woven material in metal dispersed PF resin; and
• Thermal crosslink of said PF resin.
Wherein, the thermal crosslink of said PF resin involves multiple stage curing technique including at least the following steps:

Passing said non-woven materialthrough rollers, to enable proper adhesion of metal particulate on resin matrix.

Cutting said non-woven material in specified dimension and passing such non-woven material through a roller in order to make Flute. This method of flute formation is known as a corrugation.

Stacking corrugated non-woven material one above the other to fabricate interweaves corrugation. This step enables smooth and easy air passing through Honeycomb pad. The stacked block is passed through a conveyor heating chamber.

Passing the corrugated non-woven material block through a roller,which contains glue/ adhesive.

Passing the stacked non-woven material block through a heating oven for proper adhesion of each non-woven material with the other for an additional step of thermal cross-linking.

Each corrugated non-woven material prepared by the present method, contains Antimicrobial qualities. Therefore, bacterial Killing percentage/ Reduction of bacteria/ Antimicrobial efficiency is much higher in Honeycomb cooling Pad prepared using non-woven material as prepared above. Thus enabling >99% antimicrobial activity.

An embodiment of the present invention discloses a non-woven material(100, 200) for a cooling pad (200A), the non-woven-material(100, 200) comprising:
a resin applied on surface(s) (110, 210) of the non-woven material(100, 200);
and
photochromatically activable metal oxide nanoparticles (120, 220) physically dispersed on the surface (110, 210).
Wherein, the resin is selected from a group of phenolic resin including but not limited to phenol formaldehyde or melamine formaldehyde or a water soluble resin or combination(s) thereof and wherein the non-woven material(100, 200) is preferably a cellulosic material including paper.

In an embodiment of the present invention the photochromatically activable metal oxide nanoparticles are selected from but not limited to pure metal, metal complex(s), metal salts, metal composite(s), or such other form of metal and is preferably selected from zinc oxide nanoparticles, zinc pyrithione, titanium oxide nanoparticles or silver oxide nanoparticles or combination(s) thereof.

Wherein the photochromatically activable metal oxide is activated by photochromatic light, wherein the photochromatic light is preferably ultraviolet light. More particularly, the ultraviolet light is UVC.
Another embodiment of the present invention discloses a cooling pad (200A), comprising:
a plurality of non-woven material (100, 200) stacked to form the cooling pad (200A);
at least one resin applied on at least one surface (110, 210) of the non-woven material(100, 200); and
photochromatically activable metal oxide nanoparticles (120, 220) physically dispersed on the surface (110, 210).

In an aspect of the present invention an antimicrobial cooling pad is provided. Wherein, said cooling pad is made of non-woven material having honeycomb structure, impregnated with metal loaded PF resin. Such metal is selected from but not limited to silver particles, Zinc Pyrothione, or such other metal(s) or metal complex(s).

In an embodiment of the present invention, a method for constructing an antimicrobial honeycomb cooling pad is provided. Wherein the cooling pad comprises plurality of metal impregnated non-woven material. Therefore, the combined effect of each non-woven material is contributed towards the overall increase in antimicrobial efficiency and malodor control.

WORKING EXAMPLES
EXAMPLE 1
A cooling pad made of non-woven material having 99.99% antimicrobial properties was made by the following steps:
1. Dispersing Zinc oxide nano particles in water soluble PF resin to form a zinc oxide impregnated resin;
2. Dip coating paper sheets in Zinc oxide dispersed PF resin;
3. Primary thermal crosslinking of said PF resin by passing the paper through heating rollers at a temperature 155°C;
4. Cutting the impregnated paper in a 1.5m specific diameter;
5. Corrugating paper at an angle of 45°
6. Passing the paper through a conveyor heating chamber for a secondary thermal cross-linking of zinc oxide impregnated resin at 160°C
7. Applying glue on plurality of paper sheets impregnated with zinc oxide loaded PF resin;
8. Stacking 50 sheets of corrugated & glued paper;
9. Heating at a temperature of 200°C for proper adhesion purpose and as tertiary step of thermal cross-linkage;
10. Cutting sheets at specific dimension to produce honeycomb structures

EXAMPLE 2
A cooling pad made of non-woven material, having an olfactory indicator and 99.98% antimicrobial properties was made by the following steps:
1. Dispersion of Titanium dioxide nano particles in water soluble PF resin;
2. Dip coating paper sheets in Titanium dioxide dispersed PF resin mixed with eucalyptus essential oil;
3. Primary thermal crosslinking of said PF resin by passing the paper through heating rollers at a temperature 160°C;
4. Cutting the impregnated paper in a 1.5m specific diameter;
5. Corrugating paper at an angle of 45°/45°
6. Passing the paper through a conveyor heating chamber for a secondary thermal cross-linking at 180°C
7. Applying glue on plurality of paper sheets impregnated with zinc oxide loaded PF resin;
8. Stacking 100 sheets of corrugated & glued paper;
9. Heating at a temperature of 210°C for proper adhesion purpose and as tertiary step of thermal cross-linkage;
10. Cutting sheets at specific dimension to produce honeycomb structures
Honeycomb cooling pads made using the above steps exhibited 99.98% antimicrobial properties for a period of 5 years.

UTILITY
Cooling pads disclosed in the present invention, have at least the following advantages and utility:
1. Improved Antimicrobial Cooling pad
2. Bacterial growth Control to 99%
3. Malodor Resistance.
4. Air cooler with Hygienic Air
5. Air cooler with Fresher Air
6. Reduces microbial growth on honeycomb surfaces that helps keep the air clean, odor free and safe to breathe
7. Regular Honeycomb cooling pads have shown 86.92% and 56.32% antimicrobial activity;The honeycomb pads made using the present invention show >99% antimicrobial activity when tested according to ASTM: E 2149-13a Method.
8. In current Invention each corrugated non-woven material itself possesses Antimicrobial activity, therefore bacterial Killing percentage/ Reduction of bacteria/ Antimicrobial efficiency is much higher in the Honeycomb cooling Pad of the present invention.
9. The multi-stage bacterial reduction of the present invention ensures >99.99% bacteria reduction. This results the air cooler to deliver bacteria-free, Hygienic and Fresh air.

UNIQUE FEATURES OF THE INVENTION
• No Chemical hybrid composites used in the method of the present invention.
• Cooling pad(s) made using the method of the present invention has shown >99% antimicrobial activity.
• Hand blending metal oxide nano particles in water soluble phenolic resin to disperse it without requiring any mechanical stirrer. This is achieved by using aqueous dispersion of metal oxide nano particles in Water soluble PF resin which does not require any mechanical stirrer for homogeneous mixing.
• Multi step heat curing method ensures maximum degree of Cross-linking of PF resin. This allows proper distribution/adhesion (Physical dispersion) of metal particulate in between cross-link structure of resin without making any hybrid composite.
• Adding an essential oil to the cooling pad enables the user to be informed of the level of antimicrobial properties of the cooling pad and therefore indicating to the user the correct time to change the cooling pad in order to ensure optimum antimicrobial effect throughout.

The foregoing description of the invention has been set merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the substance of the invention may occur to person skilled in the art, the invention should be construed to include everything within the scope of the disclosure.

EXPERIMENTAL DATA
Multiple lab experiments were performed to test the antimicrobial property of the cooling pad made using the present invention. The experiments were conducted on the following microorganisms:
1. Staphylococcus aureus ATCC 6538 (2.00 x 105 CFU/ ml)
2. Escherichia coli ATCC 25922 (1.80 x 105 CFU/ml)
3. Klebsiella pneumoniae ATCC 4352 (1 .50 x 105 CFU/ ml)
4. Pseudomonas aeruginosa ATCC 9027 (1.50 x 105 CFU/ ml)
5. Meticillin Resistant Staphylococcus aureus (MRSA) S- 129 (1.20 x 105 CFU/ ml)
6. Bacillus subtilis ATCC 6633 (1.50 x 105 CFU/ ml)
7. Aspergillus Niger ATCC 6275

Test 1.
DATE OF INITIATION :05/08/2019
DATE OF COMPLETION :09/08/2019
Sr. No. Sample Description
1. Honeycomb - Coated [C.D.R]- [made using Present invention]
2. Honeycomb - Uncoated [U.D.R]

Name of Test: Evaluation of Antimicrobial Activity of Fabric samples by ASTM: E 2149-13a Method

Test Organisms Used:
1. Staphylococcus aureus ATCC 6538 (2.00 x 105 CFU/ ml)
2. Escherichia coli ATCC 25922 (1.80 x 105 CFU/ml)
Quantity of Sample: l gram
Results:
Sample Identification Test Organism No. of Bacterial per Sample (CFU/ml) Percentage Reduction of Bacterial (R)
Inoculated Treated Sample at 0 hrs. (B) Inoculated Treated Sample at 24 hrs. (A)
Honeycomb Coated [C.D.R]
[made using Present invention] Staph. aureus 1.64 x 105 < 10 >99.99
Escherichia coli 1.86 x 105 < 10 >99.99
Honeycomb Uncoated [U.D.R] Staph. aureus 1.70 x 105 4.00 x 103 97.64
Escherichia coli 1.85 x 105 7.30 x 103 96.05

REMARKS:
1. CFU: Colony Forming Unit = No. of Microorganisms
2. Percentage Reduction of Microorganism (R) = 100 (B - A/ B)

INTERPRETATION: Test sample of the present invention has shown >99.99% and >99.99% antimicrobial activity; Honeycomb Uncoated [U.D.R] has shown 97.64% and 96.05% antimicrobial activity towards Staphylococcus aureus and Escherichia coli respectively when tested according to ASTM: E2149-13a Method. Therefore, non-woven material treated using the method of the present invention exhibits much higher antimicrobial properties.
Test 1B
Sample Identification Test Organism No. of Bacterial per Sample (CFU/ml) Percentage Reduction of Bacterial (R)
Inoculated Treated Sample at 0 hrs. (B) Inoculated Treated Sample at 24 hrs. (A)
Treated Honeycomb SRF No/2019730/538 [made using Present invention] K. pneumoniae 1.30 x 105 7.00 x 102 99.46
Ps. aeruginosa 1.48 x 105 7.00 x 102 99.52
MR Staph. aureus 1.54 x 105 4.80 x 102 99.68
B. Subtilis 1.50 x 105 1.80 x 102 99.88

Remarks:
1. CFU: Colony Forming Unit = No. of Microorganisms
2. Percentage Reduction of Microorganism (R) = 100 (B - A/ B)
INTERPRETATION
Test sample labeled as Treated Honeycomb - SRF No / 2019730 / 538 [made using Present invention], has shown 99.46%, 99.52%, 99.68% and 99.88% antimicrobial activity towards Klebsiella pneumoniae, Pseudomonas aeruginosa, Meticillin Resistant Staphyloccoccus aureus and Bacillus subtilis respectively when tested according to ASTM: E 2149-13a Method.

Test 2:
DATE OF INITIATION :28/11/2018
DATE OF COMPLETION :10/12/2018
Sr. No. Description Other details
1. Honey Comb Untreated
2. Honey Comb Treated
3. Flat paper Untreated
4. Flat paper Treated

Name of Test:
Assessment of Antifungal Activity, Mildew and Rot resistance of textile Materials

Test Standard:
AATCC Test Method 30; III 2017

Test Culture:
Aspergillus niger ATCC 6275
Test Specimen Size:
38 mm
Incubation Condition:
7 days in humidity chamber (> 90 % RH) at 28°C

Results:
Visual/ Microscopic Assessment Report
Sample Description Zone of Inhibition Rating Interpretation
Honey Comb Untreated No Zone 2 Light Growth (10-30%) Susceptible to fungus attack
Honey Comb Treated 2 mm 0 (No Growth) Resistant to fungus attack
Flat Paper Untreated No Zone 3 (30-60%) Susceptible to fungus attack
Flat Paper Treated 3.8 mm 0 (No Growth) Resistant to fungus attack
Whatman Filter Paper Viability Control 4 (60% to complete coverage)

INTERPRETATION
Test samples made using the present invention: non-woven material (flat paper) and cooling pad (Honey comb treated) have shown complete resistance to any fungal growth as compared to untreated material which showed a complete coverage of fungal growth/ fungal attack under same conditions.

Test 3:
DATE OF INITIATION :28/11/2018
DATE OF COMPLETION :10/12/2018
Sr. No. Description Other details
1. Honey Comb Untreated
2. Honey Comb Treated
3. Flat paper Untreated
4. Flat paper Treated

Name of Test:
Evaluation of Antifungal Activityof fabric samples by ASTEM: E 2149-13a Method

Test Culture:
1. Staphylococcus aureus ATCC 6538 (1.60 x 105CFU/ml)
2. Klebsiella pneumoniae ATCC 4352 (1.60 x 105 CFU/ml)
Sample Quantity:
1 gram
Results:
Sample pieces inContact with bacterial suspension on wrist arm shaker for 24 hr shows-
Sample Description Test Organism No. of Bacteria per sample (CFU/ml) Percentage Reduction of Bacteria (R)
Honey Comb Untreated Staph. aureus 1.53 x 105 2.00 x 104 86.92
K. pneumoniae 1.58 x 105 6.90 x 104 56.32
Honey Comb Treated Staph. aureus 1.58 x 105 1.20 x 103 99.24
K. pneumoniae 1.62 x 105 4.10 x 103 97.46
Flat Paper Untreated Staph. aureus 1.50 x 105 5.00 x 104 66.66
K. pneumoniae 1.61 x 105 8.90 x 104 44.72
Flat Paper Treated Staph. aureus 1.52 x 105 8.40 x 102 99.44
K. pneumoniae 1.65 x 105 1.54 x 103 99.06

INTERPRETATION
Test samples made using the present invention: non-woven material (flat paper) and cooling pad (Honey comb treated) have shown as high as99.44% antimicrobial activity as compared to untreated material which showed as low as 44.72% antimicrobial activity under same conditions.
,CLAIMS:
1. A method for manufacturing a non-woven material (100, 200) for a cooling pad (200A), the method comprising steps of:
applying a resin on at least one surface (110, 210) of the non-woven material (100, 200); and
physically dispersing photochromatically activable metal oxide nanoparticles (120, 220) on the surface (110, 210).

2. The method as claimed in claim 1, wherein the step of applying resin includes selecting from a group of phenolic resin including but not limited to phenol formaldehyde or melamine formaldehyde or a water soluble resin or combination(s) thereof and the step of physically dispersing metal oxide nanoparticles (120, 220) includes selecting from a group of but not limited to pure metal, metal complex(s), metal salts, metal composite(s), or other form of metal selected from a group of zinc oxide nanoparticles, zinc pyrithione, titanium oxide nanoparticles or silver oxide nanoparticles or combination(s) thereof.

3. The method as claimed in claim 1, wherein the steps of applying the resin and physically dispersing the photochromatically activable metal oxide nanoparticles (120, 220) on the surface (110, 210) is including a multi-step thermal cross-linking comprising:
a. dispersing a metal particulate in a water-soluble PF resin for forming a metal impregnated resin;
b. dip coating the non-woven material in the metal impregnated resin;
c. primary thermal cross-linking of the metal impregnated resin by heating roller(s) between 150°C and 160°C;
d. cutting and corrugating non-woven material at an angle of 45°/45° for forming a sheet of corrugated non-woven material;
e. heating the sheet in conveyor heating chamber between 160°C and 180°C for a secondary thermal cross-linking of the metal impregnated resin;
f. applying adhesive on a plurality of sheets and stacking the sheets for forming the cooling pad;
g. heating the cooling pad between 200°C and 220°C for further adhesion and a tertiary thermal cross-linking; and
h. cutting the sheets at pre-determined dimension.
4. The method as claimed in claim 1, wherein the step of physically dispersing the photochromatically activable metal oxide nanoparticles (120, 220) on the surface (110, 210) comprising adding at least one olfactory indicator, including fragrant essential oil(s), with the photochromatically activable metal oxide nanoparticles (120, 220).
5. A non-woven material (100, 200) for a cooling pad (200A), the non-woven-material (100, 200) comprising:
a resin applied on at least one surface (110, 210) of the non-woven material (100, 200); and
photochromatically activable metal oxide nanoparticles (120, 220) physically dispersed on the surface (110, 210).
6. The non-woven material (100, 200) as claimed in claim 5, wherein the resin is selected from a group of phenolic resin including but not limited to phenol formaldehyde or melamine formaldehyde or a water- soluble resin or combination(s) thereof.

7. The non-woven material (100, 200) as claimed in claim 5, wherein the non-woven material (100, 200) is preferably a cellulosic material including paper.
8. The non-woven material (100, 200) as claimed in claim 5, wherein the photochromatically activable metal oxide nanoparticles (120, 220) is selected from but not limited to pure metal, metal complex(s), metal salts, metal composite(s), or such other form of metal and is preferably selected from zinc oxide nanoparticles, zinc pyrithione, titanium oxide nanoparticles or silver oxide nanoparticles or combination(s) thereof.
9. The non-woven material (100, 200) as claimed in claim 5 or claim 8, wherein the photochromatically activable metal oxide (120, 220) is activated by photochromatic light, wherein the photochromatic light is ultraviolet light.
10. A cooling pad (200A), comprising:
a plurality of non-woven material (100, 200) stacked to form the cooling pad (200A);
at least one resin applied on at least one surface (110, 210) of the non-woven material(100, 200); and
photochromatically activable metal oxide nanoparticles (120, 220) physically dispersed on the surface (110, 210).