Architectural
Silica Aerogel Flexible Sheets for Thermal Insulation Application
Overview
ARCI has embarked on world class product development, “Silica aerogel flexible sheets” for thermal insulation application with the objectives of indigenization under the ‘Make in India’ initiative. Silica aerogel is an ultra-low density nanoporous material known for its best thermal insulation property in wide temperatures range from -50 to 800°C. In spite of all the potential benefits of aerogels, its commercial use was restricted due to its fragile nature. ARCI’s product made up of fiber-aerogel composite overcomes this limitation by making it mechanically stronger and flexible. The silica aerogel in this product has a special property of infra-red radiation reflection which helps to minimize the heat loss by radiation at high temperature. The product possesses all the properties ideally required as the best thermal insulation material such as low thermal conductivity, corrosion resistance, chemical resistance, good compressive strength, light weight, moisture resistance, fire resistance etc.
Key Features
- Thickness : 5 – 25 mm
- Thermal stability : - 50to 800 oC
- Thermal conductivity : 0.04W/mK at RT (Transient plane method)
- Density : 0.2 g/cc
- Good Mechanical strength
- Neutral in pH (water vapours passing through show pH 7) and non-corrosive
- Hydrophobic; if immersed in water for 5 hours, < 1% water is retained in the sheet
- Breathable
Potential Applications
- Thermal insulation in sectors like
- Power plants, oil & gas industries
- Architectural
- Automotive
- Defence and Aerospace
- Heat / cold storages
Intellectual Property Development Indices (IPDI) 
- Aerogel sheet production up-scaled to 300 x 3000 mm size
- Tailored to achieve all the characteristics for ideal insulation material
- Technology transferred to an Indian Industry for commercialization
Photo of Aerogel Flexible Sheet Roll
Fire Protection Property of aerogel sheet
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Major Patents / Publications
Major Patents
- An improved process for producing silica aerogel thermal insulation product with increased efficiency, Neha Hebalkar, Application number: 2141/DEL/2015
Scratch-Resistant, Single Layer Antireflective Coatings on Glass and Plastics
Overview
Glass and transparent plastics are principally used for optical applications and reflect about 8-12% of the visible light thereby decreasing transmission. Transparent plastics are being used extensively to replace glass in both industrial and domestic applications due to their low density and shock resistance. But transparent plastics are also easily prone to scratches and abrasion since they are soft in nature. Scratch resistant, anti reflective coatings (ARCs) can enhance their visible light transmission while maintaining excellent scratch resistance. From a technology point of view, single layer ARCs on glass and transparent plastics are viable for commercialization.
Key Features
- Visible light transmission ~ 97%
- Haze change after 1000 cycles of crockmeter testing using fabric: <2%
- Can be applied on Polycarbonate, PMMA and window glass
- Eco-friendly
- Low temperature ultraviolet (UV)/near-infrared (NIR) curability
- Amenability for deposition on large areas with automation
Potential Applications
- Smart windows
- Automobile windows
- Transparent glass for photovoltaic modules
- Protective glass cover for solar thermal heat collection elements
- Ophthalmic lenses
- Helmet visors
- Display glass for showcase
- Aircraft canopy
Intellectual Property Development Indices (IPDI)
- Performance and stability validated at laboratory scale on coupons
- Scale-up and prototype validation to be carried out
Transmittance spectrum of single layered antireflective coating on BSG
Photograph of object when viewed through (a) uncoated and (b) AR coated BSG substrate
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Major Patents / Publications
Major Patents
- An improved composition for antireflective coating with improved mechanical properties and a process of coating the same, Indian patent application number 2330/DEL/ 2013 dtd 05-08-13.
- S. Pavithra and R. Subasri, Sol-gel derived single layer zeolite-MgF2 composite antireflective coatings with improved mechanical properties on polycarbonate, Journal of Coating Science and Technology 1 (2014) 8-16.
Major Publications
Solar Control Coatings on Glass
Overview
Sun control films have been banned from usage in the automobile windows and windscreens since May 2012. Due to this, especially the interiors of the automobiles get very much heated up during summer because of which, the load on the air conditioners increases. Increased fuel consumption is an additional indirect effect. The same is in case of buildings that use large glass sheets as windows. Sol-gel derived fully dielectric solar control coatings that are transparent (> 70% Visible light transmittance) and have UV and NIR blocking capacities can be applied on automotive and architectural glasses to decrease the load of air conditioners inside the automotive and the buildings. A simple and cost-effective process that can generate fully dielectric solar control coatings and possessing sufficient scratch resistance has been developed.
Key Features
- Visible light transmission -35-65% vis-a -vis 90% for bare glass
- UV transmittance - 2% vis-a -vis 30% for bare glass
- NIR transmittance - 55% vis-a -vis 85% for bare glass
Potential Applications
- Architectural window glass
- Automobile side window glass/windshields
Intellectual Property Development Indices (IPDI)
- Performance and stability are validated at laboratory scale
- Proof of concept successfully completed and scale-up can be demonstrated based on the market demand
Transmittance spectra of fully dielectric solar control coating heat treated under different conditions
SEM image of solar control coating
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Major Patents / Publications
Major Patents
- An improved process to make coating compositions for transparent, UV blocking coatings on glass and a process of coating the same, Indian patent application number 1152/DEL/2014 dtd 29-04-14
- S. Manasa, R. Subasri, Effect of heat treatment on the optical properties of sol-gel derived, fully dielectric solar control coatings on glass, J. Coatings Technology and Research 13 (2016) 623-628.
Easy to clean coatings along with high optical transmittance and high weather stability
Overview
Easy to clean coating technology is generally related to protect the solar devices from dust/dirt, corrosion and all sorts of weather conditions. Reflectors and receiver tubes employed in CSP application and PV panels are very important solar devices traditionally mounted outdoors on rooftops or in wide open spaces where they can maximize their exposure to sunlight. Unfortunately, this type of outdoor placement of the devises is subjected to substantially constant weather and moisture exposure. Due to this constant and extended exposure to the devices are preferably designed for using many years of stable and reliable operation without failure due to moisture damage. A general challenge in finding the suitable protective coating material with easy to clean property for use with above mentioned devices is finding one protecting surface that has best-in-class qualities for the multifunctional properties desired in all sorts of environmental protections. This new technology will provide solution for the above mentioned issues.
Key Features
- Low cost production
- Optical property: <1% Transmission or reflection loss or equal to the actual optical property of the substrate.
- Super hydrophobic property: > 1000 water contact angle
- Good UV, weather and mechanical stability
Potential Applications
- PV panels & Reflectors employed in CSP
- Optical lenses
- Video display panels
- Architectural glasses
- Textiles
- Plastic & concrete surfaces
Intellectual Property Development Indices (IPDI)
- Performance and stability are validated at laboratory scale
- Scale up of coating, sol preparation and coating development is completed
- Prototype module fabrication & testing are under way
Image of coated PV panel & water contact angle measurement
Optical transmittance of coated PV cover glass compared with bare
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Major Patents / Publications
Major Patents
- Indian patent Application no. 402/DEL/2014, date of filling: 13.02.2014.
Decorative Nanocomposite Coatings on Glass and Ceramics
Overview
There are principally two different methods to achieve intense colors in bulk glasses; one by incorporating transition metal cations into the glass network, which absorb visible light due to electronic transitions in their atomic orbitals and the other by addition of metal salts of Au, Ag or Cu, which are reduced to the metallic state during melting and segregate from the glass matrix while cooling. The colouring of glass via melting techniques has some unique problems with respect to reproducibility, toxicology during production & recycling and economics. When differently coloured bottles are mixed during the re-melting process for recycling, desired colours are very hard to obtain. Traditionally, the decoration of crystal glasses is performed by laborious manual techniques, which are costly and do not meet modern market requirements. Sol-gel coloured/decorative coatings are thin, low temperature curable, eco-friendly alternatives and are easy to recycle.
Key Features
- Tuneable transmission and refractive index of the coatings
- Colour of the coating can be controlled by suitable choice of dopants
- UV, temperature stable and weather proof
- Easy recyclability of glass due to complete degradation of organic constituents at low temperatures
- Opaque coatings possible with high temperature durability
Potential Applications
- Architectural applications: Coloured glasses/Tiles for aesthetics or decoration
- Scratch resistant, coloured coatings for glass bottles used in various industries for storing perfume, medicines etc
Intellectual Property Development Indices (IPDI)
- Performance and stability are validated at laboratory scale
- Scale-up and large area performance evaluated
Coloured coatings on designer glass for interior applications
Transparent and opaque coloured scratch resistant coatings for glassware
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Major Patents / Publications
Major Patents
- Sol-Gel Nanocomposite Hard Coatings, K.R.C. Soma Raju and R. Subasri in "Anti-abrasive nanocoatings: Current and future applications", (ed.) M . Aliofkhazraei, Woodhead Publishing (an imprint of Elsevier), UK, 2015, pp 105-136.
- R.Subasri, C.S.Madav, K.R.C.Somaraju and G.Padmanabham, “Decorative hydrophobic sol-gel coatings densified using near-infrared radiation” Surface and coating technology, vol 206 (8-9), p 2417-2421, 2012.