NRDC Technology offer-SOL-GEL APPLICATION OF ANTI-GLARE COATINGS ON SHEET GLASS

PLANT PARAMETERS
Capacity, M²PA	150,000
No.of Shifts / day	3
Working days / Yr	300
Land Area, m2	400
Covered Area, m2	300
MANPOWER
Managerial	2
Skilled	5
Unskilled	10
PLANT & MACHINERY
Heat treatment furnaces	Stirring systems
Electrostatic air cleaner	Dip coating unit

The ultraviolet and blue spectrum light waves from the sun are harmful to eyes. The blue rays have nearly the shortest wavelength in the visible spectrum. As a result the blue colour light rays focuses slightly in front of the retina (which is the focusing screen on to which light waves fall in the eye) and causes a discomfort. The UV light is very harmful to eyes and is believed to play a role in many of the eye diseases.

The visual discomfort caused from the strong sunlight or other strong sources of illumination can be removed, at least partially, by use of suitable coloured glasses in automobile, windows in houses and offices. Although snuggles can also serve similar purpose to some extent, all coloured glasses show preferential absorption, i.e. cut-off of light transmission at certain definite wavelengths in the visible range.

The process of sol-gel coating developed at Central Glass & Ceramic Research Institute, Calcutta, India provides a method for applying an anti-glare coating on sheet glass which can control the transmission of light through it at a desired level. The coatings have the property of cutting off incident light to a desired percentage in each case which can be kept approximately constant throughout the visible range. This avoids distortion in colour of the objects viewed, which is common in coloured glasses. The coatings are found to be hard and durable and can be successfully on automobile windows, home windows and other applications. The major advantage of the process is that it is simple and does not require very costly equipment or involve technical sophistication.

PROCESS

The process involves dipping of the sheet glass in solution or sols of controlled chemical composition, followed by drying the layer at 100^o C and finally heating the dried layer at 400o- 500oC to obtain a clear, amorphous oxide layer.

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