IN228274: A process of manufacturing inorganic-organic hydrid sol and useful as scratch resistant polycarbonate sheets and lenses and other related plastics

The invention is a process for the manufacture of inorganic-organic hybrid sols suitable for scratch-resistant coating deposition up to 50 days on polycarbonate sheets and lenses been disclosed. The sol is prepared from Tetraethyl orthosilicate (TEOS), 3-glycidoxypropyltrimethoxysilane (GLYMO), 3-methacryloxypropyltrimethoxysilane (MEMO) and p-tolune sulphonic acid (PTSA) modified boemite nanoparticles dispersed in butanol-methanol mixture. Hydrolysis and condensation reactions form inorganic polymeric networks like Si-0-Si and Al-O-Si. Epoxy groups of GLYMO is polymerised in the sol stage in the presence of an initiator 1-methyl imidazole. One UV photo initiator (Benzoyl peroxide or 1-hydroxy-cyclohexyl-phenyl-ketone) is mixed with the sol to help the methacrylate polymerization during UV curing of the coating. The concentrated (viscosity in the range 18 to 32 cps) is used for coating deposition. Scratch resistant coatings of thickness 5 to 8 micrometer thick can be deposited on polycarbonate sheets and lenses by dip-coating technique. The sol, after 90 days of ageing can be reused for coating deposition after dilution with mother solvent.