| 摘要 |
<p>Phthalocyanine pigments may be purified and converted to give pure colours by reaction of the crude materials with sulphate ions. A maximum of 10 moles sulphate ions per mole of phthalocyanine is used. Reaction is carried out by milling the phthalocyanine powder with the sulphate. The sulphate ion may be added as sulphuric acid, chlorosulphuric acid and mixture of these acids with non-oxidising acids. Less sulphuric acid is required than with earlier methods reducing effluent problems and the removal of excess acid.</p> |
