Title of Invention	PROCESS FOR MAKING MIRROR-LIKE REFLECTIVE COATING ON ARTICLES
Abstract	The invention involves a process in which a non-porous metallic, painted, ceramic or plastic surface can be coated to produce brilliant reflective coating. The surface is cleaned with cleaning agents and thoroughly washed with demineralized water. Surface is then sensitized with a dilute solution of stannous chloride till a uniform sheen is obtained. An alkaline mixture of silver and ammonium nitrates is then applied to the surface simultaneously with another mixture of chemicals consisting of plain sugar, tartaric acid and alcohol. While the solutions are applied the surface is washed with a continuous flow of demineralized water. A brilliant reflective coating is obtained. The invention is useful in obtaining attractive reflective coating in various shades to look like chrome, silver, copper or gold on any large or small objects, components or products including show cars. The process is safe, simple, and economic and does not require special equipment or skills.

Title of Invention

PROCESS FOR MAKING MIRROR-LIKE REFLECTIVE COATING ON ARTICLES

Abstract

The invention involves a process in which a non-porous metallic, painted, ceramic or plastic surface can be coated to produce brilliant reflective coating. The surface is cleaned with cleaning agents and thoroughly washed with demineralized water. Surface is then sensitized with a dilute solution of stannous chloride till a uniform sheen is obtained. An alkaline mixture of silver and ammonium nitrates is then applied to the surface simultaneously with another mixture of chemicals consisting of plain sugar, tartaric acid and alcohol. While the solutions are applied the surface is washed with a continuous flow of demineralized water. A brilliant reflective coating is obtained. The invention is useful in obtaining attractive reflective coating in various shades to look like chrome, silver, copper or gold on any large or small objects, components or products including show cars. The process is safe, simple, and economic and does not require special equipment or skills.

Full Text	FORM 2 THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE OF THE INVENTION Process for making Mirror-like Reflective Coating on articles APPLICANTS TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India INVENTOR Shrinivas Madhusudan Sharangpani an Indian national of TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India PREAMBLE TO THE DESCRIPTION The following Complete specification particularly describes the invention and the manner in which it is to be performed. Field of Invention This invention relates to process for coating on articles and more specifically relates to process for making mirror-like reflective coating on large components or large objects. Background of Invention (Prior art) The process currently in use has the following steps: • Surface is cleaned • A special base paint is mixed in specific proportions of basic paint, a hardener and a thinner and applied to the surface where reflective coating is desired • Post application the base paint is cured at elevated temperature for a several hours • Main coating chemical is arrived at by mixing several chemicals in specific proportions in careful manner to avoid violent reaction • Through special equipment activating chemical is carefully applied on the surface • Surface is rinsed with demineralised water • Main coating chemical is applied to the surface • Rinsing with demineralised water • Drying • Applying top coat 2 The following are the drawbacks associated with the above process: • Special base coat paint mixing is required. Even a small variation in mixing etc would result in undesirable surface coating. • Base coat needs to be cured at elevated temperature for a long time • Main coating chemical is prepared by mixing various ingredients cautiously. Sudden mixing could cause violent reaction • Special equipment is needed for the application of main coating chemical • A great deal of attention and care is required to achieve desirable results • A huge quantity of demineralised water is required to be used in the process Brief Description of Invention This invention utilizes a chemical process to take place at the surface of the object to be coated which is sensitized before the reaction is allowed to take place. While coating is done with the help of air assisted double nozzle spray gun other application methods which mimic the said method can also be used. A combination of chemicals such as silver nitrate (AgNO3), ammonium nitrate (NH4NO3), caustic soda or sodium hydroxide (NaOH), stannous chloride (SnCl2), propanol, plain sugar and tartaric acid and their mixtures is utilized to get reflective coating. As given above, the surface is sensitized by spraying a diluted solution of sensitizer followed by rinsing with demineralized water. A mixture of main silvering chemical, catalyst and alkali is sprayed simultaneously along with 3 the reducer in such a way that the former and the latter enter the spray gun separately and get mixed just before passing through spraying nozzle. This can be accomplished either by putting barrels of the two chemicals and feeding the chemicals to the spray gun by gravity or by using two separate containers having the two chemicals (i.e. main silvering chemical and the reducer) under air pressure and feeding the gun through two separate tubes. Bright and lustrous silver coating will appear on the surface. While silvering chemicals are being sprayed it is essential to spray demineralized water at low to medium pressure. This enables quick removal of reaction byproducts from the surface eliminating the possibility of yellowing / browning. The surface then should be carefully allowed to dry. A clear lacquer top coat is applied after the above process to make the mirror-like reflective coating more durable. Objects of Invention The main object of this invention is to have a mirror-like reflective coating on large objects or components. Another object of this invention is to have a mirror-like reflective coating on objects or components to enhance their look. Another object of this invention is to have a mirror-like reflective coating on surfaces of glass, ceramics, plastics and metals. Another object of this invention is to have a mirror-like reflective coating on even an already painted metal surface 4 Another object of this invention is to have a mirror-like reflective coating on prototype products and components wherein the materials used for making them may not be finally intended materials which can be chrome plated. So in spite of a non-compatible material a near final finish can be obtained. Another object of this invention is to have a mirror-like reflective coating on cars, vehicles and aggregates for show purpose during exhibitions / expositions to enhance looks. Another object of this invention is to have a mirror-like reflective coating using conventional painting equipment. Detailed Description of Invention Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same Figure I shows a detailed flow chart of the process for making a reflective mirrorlike coating. Figure II shows results obtained by using the process as defined in this invention. Referring to Figure I the process is carried out in the following steps. 5 The surface of the article is cleaned and made free from oil, dirt etc. After cleaning it should be ensured that the surface does not contain any residues of solvent, cleaning agents etc. The surface should then be thoroughly washed with demineralized (DM) water. The surface is then sensitized with about 0.15% Stannous Chloride Solution with the help of a compressed air spray gun till a uniform sheen of water is seen. The surface is then rinsed with continuous flow of DM water to remove excess sensitizer. Prepare a solution of 6% AgNO3, 9% NH4NO3 and add about 10 to 15% of an alkaline hydroxide, more preferably, about 10.5% NaOH or about 14% KOH solution to this mixture slowly till a light brown colour is obtained and a strong smell of ammonia is detected. This solution is referred as Solution A. For each reflective coating project this solution should be prepared fresh. Prepare another solution of about 10% plain sugar and about 0.5% Tartaric acid. Boil for about 10-15 minutes. Add about 15% of alcohol, preferably ethanol, methanol or propanol and stand for 7 days. This solution is referred as Solution B. Solutions A and B should then be sprayed on the sensitized surface (as given above) simultaneously. This can be accomplished either by putting barrels of the two chemicals and feeding the chemicals to the spray gun by gravity or by using two separate containers having the two chemicals (i.e. main silvering chemical and the reducer) under air pressure and feeding the gun through two separate tubes. A double nozzle spray gun is recommended to be used for this purpose. While 6 spraying solutions A and B continuous spraying of demineralized water at the same location should be carried out It should be ensured that no residual solution remains on the surface and gets thoroughly washed. First a blackish purple coating will be observed on the surface, which will slowly convert into a bright silvery reflective coating. Spraying of Solutions A and B should be stopped as soon as a satisfactory reflective coating is obtained on the surface. Approximately equal quantities of solution A and solution B (50% - 50%) may be sprayed simultaneously on the sensitized surface. However, this ratio can vary depending on ambient conditions. The article should be rinsed with DM water even after satisfactory reflective coating is obtained. This will prevent yellowing of the fresh reflective coating. Compressed clean air is blown for water removal till surface becomes dry. The surface should not be touched. Residual water should be blown away and not allowed to dry as it would cause staining. Transparent clear coat is applied on the reflective coating. If little yellowing still persists add small amount of blue tint to clear coat. For durability, polyurethane based clear coat may be used. To get reflective coating having an appearance like gold, copper etc., a suitable tinting dye may be added to clear coat. For example, if a small quantity of yellow tint is added to clear coat and applied to the surface having reflective coating according to this invention, the effect will be a brilliant gold. If a small quantity of red tint is added to the clear coat and then applied on the surface having a reflective coating according to this invention, the effect will be a brilliant copper like appearance. 7 Figure II shows example of various substrates coated with process of this invention including a large automotive panel. Fig. IIa shows reflective coating on a pre-painted panel. The surface is brilliant and shows reflection of surroundings. Fig. lib shows reflective coating on a plastic panel having a pattern on the surface. The surface is brilliant because of coating. Reflection is dull because of pattern on the surface. Fig. lie shows a body panel of a car in which reflection of the person standing nearby is clearly seen. Surface is very reflective and brilliant. The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof. 8 WE CLAIM: 1. A Process for making mirror-like reflective coating on articles comprising the steps of: a. cleaning the surface to remove oil and dirt; b. sensitizing the surface with 0.15% Stannous Chloride Solution uniformly; c. rinsing the surface with demineralised water to remove excess / residual sensitizer; d. simultaneously applying a freshly mixed aqueous Solution A comprising 6% AgNO3 plus 9% NH4NO3 added with about 10 to 15% of an alkaline hydroxide and an aqueous Solution B comprising about 10% plain sugar, and about 0.5% Tartaric acid mixed with about 15% of lower alcohol ,and simultaneously washing the surface with DM water till a reflective mirror like coating is obtained; e. rinsing the surface with demineralised water to remove excess solutions; and f. drying the surface. 2. The process as claimed in Claim 1 wherein said ratio of alkaline hydroxide mix in Solution A is either about 10.5% NaOH or about 14% KOH and said alcohol in Solution B is chosen from the group containing ethanol, methanol or propanol. 3. The process as claimed in Claim 1 or 2 wherein a transparent clear coat is applied on the coated surface. 9 4. The process as claimed in Claims 1,2 or 3 wherein the said article is made of metal, glass, ceramic or non-porous plastic material. 5. The process as claimed in Claims 1 to 4 wherein a double nozzle spray gun or two separate spray guns are operated simultaneously in tandem to produce the reflective coating. 6. The process as claimed in Claims 1 to 5 wherein surface chemical reaction resulting in reflective coating takes place at ambient conditions. 7. The process as claimed in any of the above said Claims wherein suitable tints are added to the clear coat for e copper, gold like appearance on the article. 8. The process for making mirror-like reflective coating on articles substantially as herein described with reference to Figures I and II of the accompanying drawings. 9. Articles having a reflective mirror like coating made by a process as claimed in claims 1 to 7. Dated this 14th day of February 2007 TATA MOTORS LIMITED By their Agent and Attorney (KARUNA GOLERIA) of DePENNING & DePENNING 10

Full Text

FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Process for making Mirror-like Reflective Coating on articles
APPLICANTS
TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India
INVENTOR
Shrinivas Madhusudan Sharangpani an Indian national of TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTION
The following Complete specification particularly describes the invention and the manner
in which it is to be performed.

Field of Invention
This invention relates to process for coating on articles and more specifically relates to process for making mirror-like reflective coating on large components or large objects.
Background of Invention (Prior art)
The process currently in use has the following steps:
• Surface is cleaned
• A special base paint is mixed in specific proportions of basic paint, a hardener and a thinner and applied to the surface where reflective coating is desired
• Post application the base paint is cured at elevated temperature for a several hours
• Main coating chemical is arrived at by mixing several chemicals in specific proportions in careful manner to avoid violent reaction
• Through special equipment activating chemical is carefully applied on the surface
• Surface is rinsed with demineralised water
• Main coating chemical is applied to the surface
• Rinsing with demineralised water
• Drying
• Applying top coat
2

The following are the drawbacks associated with the above process:
• Special base coat paint mixing is required. Even a small variation in mixing etc would result in undesirable surface coating.
• Base coat needs to be cured at elevated temperature for a long time
• Main coating chemical is prepared by mixing various ingredients cautiously. Sudden mixing could cause violent reaction
• Special equipment is needed for the application of main coating chemical
• A great deal of attention and care is required to achieve desirable results
• A huge quantity of demineralised water is required to be used in the process
Brief Description of Invention
This invention utilizes a chemical process to take place at the surface of the object to be coated which is sensitized before the reaction is allowed to take place. While coating is done with the help of air assisted double nozzle spray gun other application methods which mimic the said method can also be used.
A combination of chemicals such as silver nitrate (AgNO3), ammonium nitrate (NH4NO3), caustic soda or sodium hydroxide (NaOH), stannous chloride (SnCl2), propanol, plain sugar and tartaric acid and their mixtures is utilized to get reflective coating. As given above, the surface is sensitized by spraying a diluted solution of sensitizer followed by rinsing with demineralized water. A mixture of main silvering chemical, catalyst and alkali is sprayed simultaneously along with
3

the reducer in such a way that the former and the latter enter the spray gun separately and get mixed just before passing through spraying nozzle. This can be accomplished either by putting barrels of the two chemicals and feeding the chemicals to the spray gun by gravity or by using two separate containers having the two chemicals (i.e. main silvering chemical and the reducer) under air pressure and feeding the gun through two separate tubes. Bright and lustrous silver coating will appear on the surface. While silvering chemicals are being sprayed it is essential to spray demineralized water at low to medium pressure. This enables quick removal of reaction byproducts from the surface eliminating the possibility of yellowing / browning. The surface then should be carefully allowed to dry.
A clear lacquer top coat is applied after the above process to make the mirror-like reflective coating more durable.
Objects of Invention
The main object of this invention is to have a mirror-like reflective coating on large objects or components.
Another object of this invention is to have a mirror-like reflective coating on objects or components to enhance their look.
Another object of this invention is to have a mirror-like reflective coating on surfaces of glass, ceramics, plastics and metals.
Another object of this invention is to have a mirror-like reflective coating on even an already painted metal surface
4

Another object of this invention is to have a mirror-like reflective coating on prototype products and components wherein the materials used for making them may not be finally intended materials which can be chrome plated. So in spite of a non-compatible material a near final finish can be obtained.
Another object of this invention is to have a mirror-like reflective coating on cars, vehicles and aggregates for show purpose during exhibitions / expositions to enhance looks.
Another object of this invention is to have a mirror-like reflective coating using conventional painting equipment.
Detailed Description of Invention
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same
Figure I shows a detailed flow chart of the process for making a reflective mirrorlike coating.
Figure II shows results obtained by using the process as defined in this invention.
Referring to Figure I the process is carried out in the following steps.
5

The surface of the article is cleaned and made free from oil, dirt etc. After cleaning it should be ensured that the surface does not contain any residues of solvent, cleaning agents etc. The surface should then be thoroughly washed with demineralized (DM) water.
The surface is then sensitized with about 0.15% Stannous Chloride Solution with the help of a compressed air spray gun till a uniform sheen of water is seen.
The surface is then rinsed with continuous flow of DM water to remove excess sensitizer.
Prepare a solution of 6% AgNO3, 9% NH4NO3 and add about 10 to 15% of an alkaline hydroxide, more preferably, about 10.5% NaOH or about 14% KOH solution to this mixture slowly till a light brown colour is obtained and a strong smell of ammonia is detected. This solution is referred as Solution A. For each reflective coating project this solution should be prepared fresh.
Prepare another solution of about 10% plain sugar and about 0.5% Tartaric acid. Boil for about 10-15 minutes. Add about 15% of alcohol, preferably ethanol, methanol or propanol and stand for 7 days. This solution is referred as Solution B.
Solutions A and B should then be sprayed on the sensitized surface (as given above) simultaneously. This can be accomplished either by putting barrels of the two chemicals and feeding the chemicals to the spray gun by gravity or by using two separate containers having the two chemicals (i.e. main silvering chemical and the reducer) under air pressure and feeding the gun through two separate tubes. A double nozzle spray gun is recommended to be used for this purpose. While
6

spraying solutions A and B continuous spraying of demineralized water at the same location should be carried out It should be ensured that no residual solution remains on the surface and gets thoroughly washed. First a blackish purple coating
will be observed on the surface, which will slowly convert into a bright silvery reflective coating. Spraying of Solutions A and B should be stopped as soon as a
satisfactory reflective coating is obtained on the surface. Approximately equal quantities of solution A and solution B (50% - 50%) may be sprayed simultaneously on the sensitized surface. However, this ratio can vary depending on ambient conditions.
The article should be rinsed with DM water even after satisfactory reflective coating is obtained. This will prevent yellowing of the fresh reflective coating.
Compressed clean air is blown for water removal till surface becomes dry. The surface should not be touched. Residual water should be blown away and not allowed to dry as it would cause staining.
Transparent clear coat is applied on the reflective coating. If little yellowing still persists add small amount of blue tint to clear coat. For durability, polyurethane based clear coat may be used. To get reflective coating having an appearance like gold, copper etc., a suitable tinting dye may be added to clear coat. For example, if a small quantity of yellow tint is added to clear coat and applied to the surface having reflective coating according to this invention, the effect will be a brilliant gold. If a small quantity of red tint is added to the clear coat and then applied on the surface having a reflective coating according to this invention, the effect will be a brilliant copper like appearance.
7

Figure II shows example of various substrates coated with process of this invention including a large automotive panel.
Fig. IIa shows reflective coating on a pre-painted panel. The surface is brilliant and shows reflection of surroundings.
Fig. lib shows reflective coating on a plastic panel having a pattern on the surface. The surface is brilliant because of coating. Reflection is dull because of pattern on the surface.
Fig. lie shows a body panel of a car in which reflection of the person standing nearby is clearly seen. Surface is very reflective and brilliant.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.
8

WE CLAIM:
1. A Process for making mirror-like reflective coating on articles comprising
the steps of:
a. cleaning the surface to remove oil and dirt;
b. sensitizing the surface with 0.15% Stannous Chloride Solution uniformly;
c. rinsing the surface with demineralised water to remove excess / residual
sensitizer;
d. simultaneously applying a freshly mixed aqueous Solution A comprising 6%
AgNO3 plus 9% NH4NO3 added with about 10 to 15% of an alkaline
hydroxide and an aqueous Solution B comprising about 10% plain sugar,
and about 0.5% Tartaric acid mixed with about 15% of lower alcohol ,and
simultaneously washing the surface with DM water till a reflective mirror
like coating is obtained;
e. rinsing the surface with demineralised water to remove excess solutions;
and
f. drying the surface.
2. The process as claimed in Claim 1 wherein said ratio of alkaline hydroxide
mix in Solution A is either about 10.5% NaOH or about 14% KOH and said
alcohol in Solution B is chosen from the group containing ethanol,
methanol or propanol.
3. The process as claimed in Claim 1 or 2 wherein a transparent clear coat is
applied on the coated surface.
9

4. The process as claimed in Claims 1,2 or 3 wherein the said article is made of metal, glass, ceramic or non-porous plastic material.
5. The process as claimed in Claims 1 to 4 wherein a double nozzle spray gun or two separate spray guns are operated simultaneously in tandem to produce the reflective coating.
6. The process as claimed in Claims 1 to 5 wherein surface chemical reaction resulting in reflective coating takes place at ambient conditions.
7. The process as claimed in any of the above said Claims wherein suitable tints are added to the clear coat for e copper, gold like appearance on the article.
8. The process for making mirror-like reflective coating on articles substantially as herein described with reference to Figures I and II of the accompanying drawings.
9. Articles having a reflective mirror like coating made by a process as claimed in claims 1 to 7.
Dated this 14th day of February 2007
TATA MOTORS LIMITED By their Agent and Attorney

(KARUNA GOLERIA)
of DePENNING & DePENNING
10

Documents:

296-MUM-2007-ABSTRACT(14-2-2007).pdf

296-mum-2007-abstract(granted)-(3-10-2008).pdf

296-MUM-2007-CANCELLED PAGES 14-2-2007.pdf

296-MUM-2007-CANCELLED PAGES(11-6-2008).pdf

296-MUM-2007-CLAIMS 11-6-2007.pdf

296-MUM-2007-CLAIMS(14-2-2007).pdf

296-mum-2007-claims(granted)-(3-10-2008).pdf

296-mum-2007-claims.doc

296-mum-2007-claims.pdf

296-mum-2007-correspondance-received.pdf

296-MUM-2007-CORRESPONDENCE 11-6-2007.pdf

296-MUM-2007-CORRESPONDENCE(11-6-2008).pdf

296-MUM-2007-CORRESPONDENCE(IPO)-(10-11-2008).pdf

296-mum-2007-description (complete).pdf

296-MUM-2007-DESCRIPTION(COMPLETE) 11-6-2007.pdf

296-MUM-2007-DESCRIPTION(COMPLETE)-(14-2-2007).pdf

296-mum-2007-description(granted)-(3-10-2008).pdf

296-MUM-2007-DRAWING 11-6-2007.pdf

296-MUM-2007-DRAWING(14-2-2007).pdf

296-MUM-2007-DRAWING(AMENDED)-(11-6-2008).pdf

296-mum-2007-drawing(granted)-(3-10-2008).pdf

296-mum-2007-drawings.pdf

296-MUM-2007-FORM 18(10-4-2007).pdf

296-MUM-2007-FORM 2(COMPLETE)-(14-2-2007).pdf

296-mum-2007-form 2(granted)-(3-10-2008).pdf

296-mum-2007-form 2(title page)-(granted)-(3-10-2008).pdf

296-MUM-2007-FORM 8 11-6-2007.pdf

296-MUM-2007-FORM 9(10-4-2007).pdf

296-mum-2007-form-1.pdf

296-mum-2007-form-2.doc

296-mum-2007-form-2.pdf

296-mum-2007-form-26.pdf

296-mum-2007-form-3.pdf

296-MUM-2007-GENERAL POWER OF ATTORNEY(14-2-2007).pdf

296-MUM-2007-POWER OF ATTORNEY 11-6-2007.pdf

296-MUM-2007-SPECIFICATION(AMENDED)-(11-6-2008).pdf

321-MUM-2000-FORM 2(COMPLETE)-(7-4-2000).pdf

321-MUM-2000-FORM 2(TITLE PAGE)-(7-4-2000).pdf

321-MUM-2000-FORM 3(27-12-2004).pdf

321-MUM-2000-FORM 3(7-4-2000).pdf

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Patent Number

224189

Indian Patent Application Number

296/MUM/2007

PG Journal Number

06/2009

Publication Date

06-Feb-2009

Grant Date

03-Oct-2008

Date of Filing

14-Feb-2007

Name of Patentee

TATA MOTORS LIMITED

Applicant Address

BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI-400 001. MAHARASHTRA, INDIA.

Inventors:

#	Inventor's Name	Inventor's Address
1	SHRINIVAS MADHUSUDAN SHARANGPANI	BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI-400 001. MAHARASHTRA, INDIA.

PCT International Classification Number

C03C17/00

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA