Products in the thermolysis of typical organic pigments for sol-gel colored coating of glass bottles, diketopyrrolopyrrole (C.I. Pigment Red 254), copper phthalocyanine (C.I. Pigment Blue 15 : 3), and yellow metal complex (C.I. Pigment Yellow 150), and coating solutions containing those organic pigments, were analyzed with thermal gravimetric (TG) analysis, X-ray diffractometer, IR spectrophotometer, and GC-MS spectrometer.
Carbon dioxide and water were mainly detected by the IR spectroscopic analysis of the decomposed gasses in thermolysis of the organic pigments at 550°C. When copper phthalocyanine and yellow metal complex containing transition metals were heated under the atmosphere until 1000°C, the transition metals turned to metal oxides as residue in the thermolysis. Actually, copper (II) oxide and nickel (II) oxide derived from these pigments were confirmed in silica matrix by X-ray diffraction and TG analyses.
In the GC-MS analysis of the products in convenient thermolysis of organic pigments in a small glass tube, some substituted benzene derivatives were detected because of the insufficient combustion of diketopyrrolopyrrole and copper phthalocyanine.
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