Лако-красочные материалы — производство

Fluoran compounds have an optically active spiro-carbon atom. Con­sequently, some fluoran compounds, especially those having an alkylamino group of four or more carbon atoms at 3′-position, have been found to exhibit crystal modifications as determined by X-ray diffraction. Each crystal modification reveals different physical properties such as melting point, solubility, and affinity with acidic compounds, resulting in different characteristics regarding use for carbonless copying papers, thermosensitive recording papers, and the like.

Table 1 shows a few examples of fluoran compounds having crystal modifications.