DESC:FORM 2

THE PATENTS ACT,
(39 OF 1970)
THE PATENT RULES, 2003.

COMPLETE SPECIFICATION
(SECTION 10 AND RULE 13)

COATED GLASS WITH ULTRAVIOLET BLOCKING, INFRARED REFLECTING AND SELF-CLEANING LAYERS AND PROCESS FOR PREPARATION THEREOF

INM Technologies Private Limited
(Innovative Nano & Micro Technologies Private Limited)
An Indian Company having its address at
#4 T.M. Industrial Estate, 12th KM, Mysore Road
Bangalore-59, Karnataka State, India

The following specification particularly describes the invention and the manner in which it is performed

FIELD OF INVENTION

The present invention relates to glass materials, in particular to the construction of multifunctional glass and its preparation method thereof.

BACKGROUND OF THE INVENTION

Ultraviolet (UV) rays will cause the aging of organic matter, in some special occasions need to prevent UV light passing from the glass. At present, the preparation of UV glass is prepared by adding cerium ions to the glass component, but the UV transmittance of the glass is still high, further the process of addition of cerium ions to glass is complicated which involves a melting method and it is not easy to control the amount of cerium ions to be added.

Infrared (IR) light will pass through the glass, and in summer, the indoor temperature rises, and in winter heat from the indoor passes to outside, both of which will increase the air condition refrigeration and heating respectively. The glass substrate coated with infrared film, can reduce the glass emissivity, to achieve the purpose of energy saving.

US Patent No.7,744,951 discloses a dual function coated glass having an IR blocking coating and UV blocking coating, which is capable of blocking significant amounts of both IR and UV radiation, which solves the above problems.

US Patent No.7,288,232 discloses a dual function self-cleaning UV reflective coating, wherein the self-cleaning layer contains the TiO2.

In order to solve the drawbacks of the above prior art references, which solves only one or two problems of light or air pollution by single coating or double coating of glass, the inventors of CN101054268A Publication have developed a multi-functional coated glass having IR reflective layer, UV blocking layer, and photocatalytic sterilization layers. Further CN ‘268 Publication discloses that the IR reflective layer has a chemical composition selected from In2O3: Sn film, SnO2: Sb film or ZnO: Al film, the UV blocking layer has the chemical composition of titanium dioxide and cerium oxide complex, and the photocatalytic sterilization layer has the chemical composition of titanium dioxide, wherein each layer is coated on the glass by magnetron sputtering method.

The coated glass as disclosed in the above prior art references has a wide application prospect in buildings, automobiles and lamps. The multi-functional glass as disclosed in the above prior art references uses the materials that are costly such as indium and a tedious process of magnetron sputtering that should be done in a manufacturing facility. Therefore, there exists a need for a multi-functional coated glass with low cost that has the simple fabrication process and can be prepared outside the manufacturing facilities.

OBJECTS OF THE INVENTION

Object of the present invention is to prepare a multifunctional coated glass with UV blocking, IR reflecting and self-cleaning layers.

Another object of the present invention is to provide a method for preparing such multifunctional coated glass.

SUMMARY OF THE INVENTION

The present invention relates to the multifunctional coated glass with UV blocking, IR reflecting and self-cleaning layers and the process for preparation thereof.

In embodiments of the invention, the present invention relates to a multifunctional coated glass substrate coated with an UV blocking film layer, an IR reflecting film layer and a self-cleaning film layer (the sequence of the UV blocking film layer and IR reflecting film layer can be changed with each other); wherein the chemical composition of UV blocking layer is: a compound of titanium oxide and cerium oxide; the chemical composition of infrared reflecting layer is: the compound of cadmium oxide and tin oxide; the chemical composition of self-cleaning film layer is: the compound of titanium oxide, cerium oxide, tin oxide and zinc oxide.

In embodiments of the invention, the present invention relates to a multifunctional coated glass substrate coated with an UV blocking film layer, an IR reflecting film layer and a self-cleaning film layer, wherein the chemical composition of UV blocking layer consists of titanium oxide and cerium oxide; the chemical composition of infrared reflecting layer consists cadmium oxide and tin oxide; and the chemical composition of self-cleaning film layer consists of titanium oxide, cerium oxide, tin oxide and zinc oxide.

In a specific embodiment, the present invention relates to a glass substrate coated with an UV blocking film layer, an IR reflecting film layer a self-cleaning film layer, wherein the chemical composition of UV blocking layer is: a compound of titanium oxide and cerium oxide in the ratio of 1:1 (molar basis); the chemical composition of infrared reflecting layer is: the compound of cadmium oxide and tin oxide in the ratio of 1:1 (molar basis); the chemical composition of self-cleaning film layer is: the compound of titanium oxide, cerium oxide, tin oxide and zinc oxide in the %v/v concentrations of 80 to 90% v/v of titanium oxide, 2 to 5% of cerium oxide, 2 to 5% v/v of tin oxide and 10-15% v/v of zinc oxide based on the total coating of the self-cleaning film layer.

In another embodiment, the present invention relates to a process for preparation of multifunctional coated glass consists the steps of: first cleaning, drying the glass substrate, preparing the target material, coating the film layer by the dip coating method or spray coating method.

In certain embodiments of this invention, a method of making the multifunctional coated glass is provided. A glass substrate to be coated is provided. A UV-blocking coating layer is disposed on the glass substrate to be coated. A IR reflecting coating layer is disposed over the UV blocking coating layer. A self-cleaning layer is disposed over the IR reflecting coating layer.

The features, aspects, advantages, and example embodiments described herein may be combined to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages will be better and more completely understood by reference to the following detailed description of exemplary illustrative embodiments in conjunction with the drawings, of which:

Fig 1 is a multifunctional coated glass supporting a UV blocking layer, IR reflecting layer and a self-cleaning layer in accordance with an example-1.

Fig 2 shows the illustrative process for making the multifunctional coated glass of Fig 1 as disclosed in example-1.

Fig 3 is a transmittance (%T) vs. wavelength (nm) graph illustrating the spectral response of multifunctional coated glass of example-1 herein compared to other uncoated articles in the wave length range of 200 to 800nm.

Fig 4 is a temperature vs. time graph illustrating the temperature in °C absorbed by the multifunctional coated glass of example-1 herein compared to other uncoated articles (It includes the glass cubes which are coated on one side and glass cubes that are coated on all sides, cement cube with coated glass on the top surface, wooden cube with the coated glass on the top surface).

Fig 5 discloses the contact angle of the multifunctional coated glass of example-1.

Fig 6 discloses the contact angle of the uncoated glass.

Fig 7 describes the methylene blue degradation test as per ISO 10678:2010 on multifunctional coated glass as disclosed in example-1.

Fig 8 describes the stearic acid degradation test as per ISO 27448:2009 on multifunctional coated glass as disclosed in example-1.

DETAILED DESCRIPTION OF THE INVENTION

In certain example embodiments of this invention, multifunctional coated glass is provided that blocks significant amount of both IR & UV radiation and further has self-cleaning properties. Such multifunctional coated glass may be used in the context of windows such as architectural windows, insulated glazing window units, vehicle windows, and/or the like.

In certain example embodiments of the invention, a UV blocking coating is provided on the glass substrate, over which a IR reflecting coating is provided and over which a self-cleaning coating layer is provided as illustrated in Fig 1.

In embodiments of the invention, the present invention provides a multifunctional coated glass substrate coated with an UV blocking film layer, an IR reflecting film layer and a self-cleaning film layer, wherein the chemical composition of UV blocking layer consists of titanium oxide and cerium oxide; the chemical composition of infrared reflecting layer consists cadmium oxide and tin oxide; and the chemical composition of self-cleaning film layer consists of titanium oxide, cerium oxide, tin oxide and zinc oxide.

In the specific embodiments of the invention chemical composition of UV blocking layer is: a compound of titanium oxide and cerium oxide in the ratio of 1:1 (molar basis); the chemical composition of infrared reflecting layer is: the compound of cadmium oxide and tin oxide in the ratio of 1:1 (molar basis); the chemical composition of self-cleaning film layer is: the compound of titanium oxide, cerium oxide, tin oxide and zinc oxide in the in the %v/v concentrations of 80 to 90% v/v of titanium oxide, 2 to 5% v/v of cerium oxide, 2 to 5% v/v of tin oxide and 10-15% v/v of zinc oxide based on the total coating of the self-cleaning film layer.

In certain example embodiments of the invention, the UV blocking coating may be formed as follows: A liquid coating solution (for a UV blocking coating that blocks significant amount of UV radiation) is prepared by combining a titania sol or sol-gel with cerium oxide inclusive solution. In certain specific example embodiments, titanium alkoxides as a metal organic compound may be used as the starting material for the preparation of titania sol. Titanium alkoxides include, for example, titanium tetramethoxide, titanium tetraethoxide, titanium isopropoxide, titanium n-propoxide, titanium tetra n-butoxide, titanium tetraisobutoxide, titanium methoxypropoxide, and titanium dichloride diethoxide. In certain example embodiments, the titania sol may include from about 0 to 0.5M titania, more preferably from about 0.1 to 0.3M titania.

The cerium oxide inclusive solution may be a cerium nitrate hexahydrate solution in certain example embodiments of this invention, although other types of cerium oxide inclusive solution may instead be used. In certain example embodiments, the ceria inclusive solution includes from about 0 to 0.5M ceria, more preferably from about 0.1 to 0.3M ceria.

The mixture of the titania sol and the ceria inclusive solution may be stabilized by an additive in certain example embodiments of UV blocking coating. An alcohol (e.g. ethanol, 2-methoxy ethanol, butanol or isopropyl alcohol) may be used as a solvent in the wet coating solution in certain example instances of UV blocking coating. Examples of compounds that may be used as stabilizer additives include glycols, alcohols, polyols, beta-diketones, amines, amino alcohols and acetic acid esters. Examples of additives that may be used as a stabilizer in the wet coating solution include mono and dialkyl ethers of ethylene glycol and/or propylene glycol, acetyl acetone, acetoacetic acid, cyanoethylacetate, ethylacetoacetate, polyethylene glycols, caprolactone polyols, acrylic polyols, triethanolamine, methyl diethanolamine, and EDTA.

The coating solution including the titania sol and the ceria inclusive solution may be applied by dip coating or spray coating on a glass substrate. In the specific examples, if the coating solution is applied by spray coating on a glass substrate, after the spray coating, the UV coating was cured using hot air gun which is also optimized for the distance and speed to get 200 to 250 °C temperature.

In certain example embodiments of the invention, the IR reflecting coating may be formed as follows: a liquid coating solution (for a IR reflecting coating that reflects significant amount of IR radiation) is prepared by combining a cadmium sol or sol-gel with tin oxide inclusive solution. In certain specific example embodiments, cadmium acetate may be used as the starting material for the preparation of cadmium oxide sol. In certain example embodiments, the cadmium oxide sol may include from about 0 to 0.3M cadmium oxide, more preferably from about 0.1 to 0.2M cadmium oxide.

In certain specific example embodiments tin chloride dihydrate may be used as the starting material for the preparation of the tin oxide sol. In certain example embodiments, the tin oxide inclusive solution includes from about 0 to 0.3M of tin oxide, more preferably from about 0.1 to 0.2M tin oxide. An alcohol (e.g. ethanol, 2-methoxy ethanol, butanol or isopropyl alcohol) may be used as a solvent in the wet coating solution in certain example instances of IR reflecting coating. Examples of compounds that may be used as stabilizer additives in IR reflecting coating include glycols, alcohols, polyols, beta-diketones, amines, amino alcohols and acetic acid esters. Examples of additives that may be used as a stabilizer in the wet coating solution include mono and dialkyl ethers of ethylene glycol and/or propylene glycol, acetyl acetone, acetoacetic acid, cyanoethylacetate, ethylacetoacetate, polyethylene glycols, caprolactone polyols, acrylic polyols, triethanolamine, methyl diethanolamine, and EDTA.

The coating solution including the cadmium oxide sol and tin oxide inclusive solution may be applied by dip coating or spray coating on a UV blocking coating.

In certain example embodiments of the invention, the self-cleaning coating may be formed as follows: A liquid coating solution (for a self-cleaning coating which is also known as photocatalytic coating utilise the rain and super hydrophilic nature of the coating combined with photo catalytic activity to clean the surface of the glass) is prepared by combining a titania sol, ceria sol, zinc oxide sol or sol-gel with tin oxide inclusive solution.

In certain specific example embodiments, Titanium isopropoxide may be used as the starting material for the preparation of titana sol. In certain example embodiments, the titania sol may include from about 0 to 0.5M titania, more preferably from about 0.1 to 0.3M titania.

In certain embodiments ceria sol, used in the preparation of self-cleaning layer may be a cerium nitrate hexahydrate solution, although other types of cerium oxide inclusive solution may instead be used. In certain example embodiments, the ceria sol includes from about 0 to 0.5M ceria, more preferably from about 0.1 to 0.3M ceria.

In certain example embodiments zinc oxide sol, used in the preparation of self-cleaning layer may be a zinc acetate dihydrate solution, although other types of zinc oxide inclusive solution may instead be used. In certain example embodiments, the zinc oxide sol includes from about 0 to 0.5M zinc oxide, more preferably from about 0.1 to 0.3M zinc oxide.

In certain example embodiments tin oxide sol, used in the preparation of self-cleaning layer may be a tin chloride dihydrate solution, although other types of tin oxide inclusive solution may instead be used. In certain example embodiments, the tin oxide sol includes from about 0 to 0.5M tin oxide, more preferably from about 0.1 to 0.3M tin oxide.

An alcohol (e.g. ethanol, 2-methoxy ethanol, butanol or isopropyl alcohol) may be used as a solvent in the wet coating solution in certain example instances of self-cleaning coating. Examples of compounds that may be used as stabilizer additives include glycols, alcohols, polyols, beta-diketones, amines, amino alcohols and acetic acid esters. Examples of additives that may be used as a stabilizer in the wet coating solution of self-cleaning coating include mono and dialkyl ethers of ethylene glycol and/or propylene glycol, acetyl acetone, acetoacetic acid, cyanoethylacetate, ethylacetoacetate, polyethylene glycols, caprolactone polyols, acrylic polyols, triethanolamine, methyl diethanolamine, and EDTA.

The self-cleaning coating solution including the titania sol, ceria sol, zinc oxide sol and tin oxide inclusive solution may be applied by dip coating or spray coating on a IR reflecting coating.

The following examples are provided to illustrate the present invention. It should be understood, however, that the invention is not limited to the specific conditions or details described in the examples below. The examples should not be construed as limiting the invention as the examples merely provide specific methodology useful in the understanding and practice of the invention and its various aspects. While certain preferred and alternative embodiments of the invention have been set forth for the purposes of disclosing the invention, modification to the disclosed embodiments can occur to those who are skilled in the art.

Example 1: Preparation of multifunctional coated glass by Dip Coating Method

Preparation of UV blocking coating solution:

A coating solution (for UV blocking coating that blocks the significant amount of UV radiation) was prepared by combining 50%(v/v) of pre-hydrolysed titanium isopropoxide sol of about 0.2 M of titania in isopropyl alcohol, and about 50%(v/v) of cerium (III) nitrate solution of about 0.2 M ceria in isopropyl alcohol. The mixture was stabilized using 0.3M Acetyl Acetone.

Preparation of IR reflective coating solution:

A coating solution (for IR reflective coating that reflects the significant amount of IR radiation) was prepared by combining 50%(v/v) of pre-hydrolysed cadmium acetate sol of about 0.15 M of cadmium in isopropyl alcohol, and about 50%(v/v) of tin oxide solution of about 50% (v/v) tin oxide (0.15 M) in Isopropyl alcohol.

Preparation of Self-cleaning coating solution:

A coating solution (for self-cleaning coating that uses photo catalytic activity to clean the surface of the glass) was prepared by combining 80%(v/v) of pre-hydrolysed titanium isopropoxide sol of about 0.2M of titania in isopropyl alcohol, and about 5%(v/v) of cerium (III) nitrate solution of about 0.2M by weight ceria in isopropyl alcohol and about 5%(v/v) of tin solution of about 0.2 M cerium oxide in isopropyl alcohol and about 10%(v/v) of Zinc nitrate solution of about 0.2 M zinc oxide in isopropyl alcohol. 5%(v/v) of tin solution of about 0.2 M tin oxide in isopropyl alcohol and about The mixture was stabilized using 0.3M Acetyl Acetone.

Dip Coating Procedure:

Pre-cleaning of Glass substrates:

a. Clean the substrates with soap water.
b. Rinse the substrate with distilled water.
c. Rinse the substrate with Isopropyl alcohol / Ethanol.
d. Finally rinse the substrate with distilled water.
e. Dry the substrate with soft tissue / cloth.

Dip Coating for small substrates:

a. The first layer (UV absorbing) was coated on glass substrate using dip coating unit with preprogramed settings like, Dip speed, Withdrawal speed, Drying time etc. Dipping cycles were in the range of one to three dips depending on the required thickness of the layer.

b. The second layer (IR reflective) was coated on glass substrate on top of first layer keeping all the preprogramed settings constant of dip coating used for first layer. Dipping cycles were in the range of one to three dips depending on the required thickness of the layer.

c. The third layer (self-cleaning) was coated on glass substrate on top of second layer keeping all the preprogramed settings constant of dip coating used for first and second layer. Dipping cycles were in the range of one to three dips depending on the required thickness of the layer.

Each layers were preheated at 70 – 100 °C before applying the next layer. After applying the final / third layer the substrate was subjected to annealing at 200-300 °C.

Example 2: Preparation of multifunctional coated glass by Spray Coating Method

Preparation of UV blocking coating solution

A coating solution (for UV blocking coating that blocks the significant amount of UV radiation) was prepared by combining 50%(v/v) of pre-hydrolysed titanium isopropoxide sol of about 0.2 M of titania in isopropyl alcohol and about 50%(v/v) of cerium (III) nitrate solution of about 0.2 M ceria in isopropyl alcohol. The mixture was stabilized using 0.3M Acetyl Acetone.

Preparation of IR reflective coating solution

A coating solution (for IR reflective coating that reflects the significant amount of IR radiation) was prepared by combining 50%(v/v) of pre-hydrolysed cadmium acetate sol of about 0.15 M of cadmium oxide in isopropyl alcohol, and about 50%(v/v) of tin oxide solution of about 50% (v/v) by tin oxide (0.15 M) in Isopropyl alcohol.

Preparation of Self-cleaning coating solution:

A coating solution (for self-cleaning coating that uses photo catalytic activity to clean the surface of the glass) was prepared by combining 80%(v/v) of pre-hydrolysed titanium isopropoxide sol of about 0.2M of titania in isopropyl alcohol, and about 5%(v/v) of cerium (III) nitrate solution of about 0.2M ceria in isopropyl alcohol and about 5%(v/v) of tin solution of about 0.2M tin in isopropyl alcohol and about 10%(v/v) of Zinc nitrate solution of about 0.2M zinc oxide in isopropyl alcohol. The mixture was stabilized using 0.3M Acetyl Acetone.

Spray Coating for larger substrates:

a. The first layer (UV absorbing) was coated on glass substrate using manual spray coating unit which was optimized for distance, flow rate and speed. After applying the first layer the coating was cured using hot air gun which is also optimized for the distance and speed to get 200 to 250°C temperature.

b. The second layer (IR reflective) was coated on the first layer using manual spray coating unit. Coating parameters were maintained same as of first layer.

c. The third layer (self-cleaning) was coated on the second layer using manual spray coating unit. Coating parameters were maintained same as of first and second layers.

,CLAIMS:
We Claim

1. A multifunctional coated glass substrate coated with an UV blocking film layer, an IR reflecting film layer and a self-cleaning film layer, wherein the chemical composition of UV blocking layer consists of titanium oxide and cerium oxide; the chemical composition of infrared reflecting layer consists cadmium oxide and tin oxide; and the chemical composition of self-cleaning film layer consists of titanium oxide, cerium oxide, tin oxide and zinc oxide.

2. The multifunctional coated glass substrate according to claim 1, wherein UV blocking layer consists of titanium oxide and cerium oxide in the ratio of 1:1.

3. The multifunctional coated glass substrate according to claim 1, wherein IR reflecting film layer consists of cadmium oxide and tin oxide in the ratio of 1:1.

4. The multifunctional coated glass substrate according to claim 1, wherein self-cleaning layer consists of 80 to 90% v/v of titanium oxide, 2 to 5% v/v of cerium oxide, 2 to 5% v/v of tin oxide and 10-15% v/v of zinc oxide based on the total coating of the self-cleaning film layer.