Лако-красочные материалы — производство

6.2.2. Reaction of Keto Acids with Phenols The reaction of keto acids with phenols is mainly used to prepare fluoran compounds developing colors from orange to red. That is, keto acids (66) react with a wide variety of phenols (67) to give 3′-aminofluorans (68) (Eq. 1). Table 1. Crystal Modifications of Fluoran Compounds R1 R2 […]

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, […]

Extension of conjugated double bond system at 2′- and/or 6′-positions makes it possible for fluoran compounds to have an absorption in the near infrared region up to 1200 nm. These include 2′-anilino-6-(4-anilinoanilino)- 3′-methylfluoran (62),63 6′-[4-(4-anilinoanilino)anilino]-2′-chloro- 3′-methylfluoran (63),7 6′-[4-(4-dimethylaminoanilino)anilino]-2′-methylflu- (62) (63) oran (64),64 and 6′-diethylamino-2′-[4-(4-dimethylaminoanilino)anilino]-3′- methylfluoran (65).65

The most remarkable feature of fluoran compounds is producing singly black color, which can hardly be attained by any other class of leuco dyes. One of the typical black developing fluoran compounds is 2′-anilino-6′- diethylamino-3′-methylfluoran (50)6 in which the methyl group at 3′-posi — tion plays a very important role. The parent structure of 50 […]

Fluoran compounds having two tertiary amino groups at 2′- and 6′-positions generally develop green color. For example, 2′,6′-bis(diethyl- amino)fluoran (42; R1, R2 = C2H5),5 2′-(N-benzyl-N-ethylamino)-6′-di — ethylaminofluoran (42; R1 = C2H5, R2 = C6H5CH2),5 2′-dibenzylamino-6′- diethylaminofluoran (42; R1, R2 = C6H5CH2),5 6′-diethylamino-2′-diphen- ethylaminofluoran (42; R1, R2 = C 6H5C2H4),34 6′-diethylamino-2′-(N — methylanilino)fluoran (42; R1 = […]

Fluoran compounds having two diarylamino groups at 3′- and 6′- positions generally develop blue tone colors. For example, 3′,6′-bis — (diphenylamino)fluoran (34; R1, R2 = H)29 develops reddish blue color, and 3′-diphenylamino-6′-di-p-tolylaminofluoran (34; R1 = H, R2 = CH3)29 and 3′,6′-bis(di-p-tolylamino)fluoran (34; R1, R2 = CH3)29 blue color. (34) If at least one of the […]

Fluoran compounds having a monosubstituted amino group at 3′-posi­tion generally develop orange color. Cyclohexyl group is most desirably used as the substituent on amino groups, though linear alkyl and aralkyl groups are also employed to give orange color. These include 2′-chloro-6′- cyclohexylaminofluoran (17; R1 = H, R2 = Cl),4 3′-chloro-6′-cyclohexyl — aminofluoran (17; R1 = […]

Fluoran compounds have the remarkable feature of giving a wide variety of colors depending on their substituent(s). The following will discuss the effect of substituents for each developing color. 6.2.1.1. Yellow Developing Fluorans Fluoran compounds having two alkoxy groups at 3′- and 6′-posi- tions develop yellow color, but the color intensity is not very high. […]

6.2.1. Color-Formation Reaction Colorless or nearly colorless fluoran compounds having appropriate substituent(s) react with acidic compounds to open their lactone rings resulting in extension of the conjugated double bond system, enabling color formation. Lactone ring opening can be determined very easily by the disappearance of lactone absorption around 1760 cm-1 in the infrared spectrum. For […]

YOSHIHIRO HATANO 6.1. INTRODUCTION In our information-oriented society, computer and facsimile are being widely used as a means for transmitting information. Carbonless copying papers and thermosensitive recording papers, which utilize a color-forma­tion reaction between leuco dyes and acidic compounds, have won high regard as recording papers used with these office machines. The leuco dyes are […]