Large size recyclable colored glass plates prepared from organic colorant dispersed silica sols by the dipping method

We have prepared the recyclable colored glass plates of blue, green, or red by coating organic colorant dispersed silica sols. Phthalocyanine-type or diketopyrrolopyrrole-type compounds were used as colorants for colored coat ing and the sol coated glass plates were heat-treated at 300-400 degreesC. The coating was done by using a dipping-withdrawing equipment designed orig inally for coating large sized glass plates with 2 m in length and 1 m in w idth. The colored coating films were uniform and transparent with low haze values less than 1.0% and with thickness of 120-540 nm. The visible light t ransmittance of the colored glass plates was controlled in the relatively w ide range of 50-90% by changing the film thickness or the colorant concentr ation in the coating sols. The practical durabilities of the blue colored g lass plate against abrasion, scratch, chemicals and UV-light were acceptabl e to the specification required for interior glass products.