Лако-красочные материалы — производство

6.4.1.2. Background Thermosensitive recording paper was introduced by the National Cash Register Company in 1968. The chemistry employed is essentially the same as that for carbonless papers, i. e., color-formation reaction between leuco dye and coreactant, though thermosensitive recording papers require certain unique leuco dyes and coreactants. Thermosensitive recording papers gen­erally consist of a single-sheet […]

Microencapsulation is a revolutionary technology enabling liquids to be treated as solids. The technology was first used to produce carbonless copying paper, but today it is widely used in a number of industrial fields such as medicine, agricultural chemicals, thermochromic materials, cos­metics, and toiletries. The original microcapsule was produced by a complex coacervation between gelatin […]

A leuco dye(s) solution in a nonvolatile solvent is encapsulated in microcapsules 5-10 pm in diameter, and after addition of latex and wheat starch, coated (at about 5 g/m2 as dry solid) on a substrate such as paper, synthetic paper, or plastic film, and dried to give the CB sheet. The solvent should have high […]

6.4.1.1. Background In 1954, the National Cash Register Company introduced a new copying system, i. e., carbonless copying paper, by which multiple copies were realized without using traditional carbon paper. Since then, there have been numerous changes and improvements, though the original system is still the technological basis for the current carbonless copying papers. Colored […]

Fluoran compounds have been used in a variety of fields. These include sublimation transfer printing, thermoindicator, printed circuits, writing materials, textile finishing, etc., though recording papers, i. e., carbonless copying paper and thermosensitive recording paper, are extraordinarily large in volume. This section describes carbonless copying paper and thermosensitive recording paper.

Treatment of 2′-anilinofluorans with ketones such as acetone or 2- butanone in hydrochloric acid in the presence of iron(III) chloride gives 4,4′-alkylidenebis(N-fluoran-2-ylaniline)s. Thus, 2′-anilino-6′-(N-cyclohexyl- N-methylamino)-3′-methylfluoran, (86) is treated with acetone in hydrochlo­ric acid in the presence of iron(III) chloride to give 2,2-bis(4-[6′-(N- cyclohexyl-N-methylamino)-3′-methylfluoran-2′-ylamino]phenyl}propane (87)60 (Eq. 9). (9) Treating 2′-anilino-6′-[N-ethyl-N-(3-methoxypropyl)amino]-3′-methyl- fluoran (88) with 48% hydrobromic acid […]

3 ‘-Chlorofluorans react with a wide variety of primary amines such as alkylamines, cycloalkylamines, aralkylamines, and arylamines, as well as cyclic secondary amines such as piperidine, morpholine, etc., to prepare 3’-aminofluorans. The typical example is, however, the reaction of 3′-chlorofluoran (84) with cyclohexylamine to give 3′-cyclohexylaminofluorans (85) (Eq. 8). The reaction is successfully carried out […]

The reaction of 2′-aminofluorans with aralkyl halides is solely used to prepare 2′-diaralkylaminofluorans developing red or green colors. Thus, 2′-aminofluorans (82) reacts with benzyl chloride in organic solvent such as isopropanol or toluene at reflux in the presence of potassium carbonate or sodium carbonate to give 2′-dibenzylaminofluorans (83) in excellent yield. (Eq. 7). Besides benzyl […]

The reaction of keto acids (79) having no amino group with 3-alkoxy — diphenylamines (80) is used to synthesize 3 ‘-anilinofluorans (81), especially near-infrared-absorbing fluoran compounds (Eq. 6). (6) Table 7 shows melting points of a few near-infrared-absorbing fluoran compounds (81) thus prepared. Preparation of 6′-[4-(4-Anilinoanilino)anilino]-2′-chloro-3′-methylflu — oran (81a). To concentrated sulfuric acid (10 g) […]

The reaction of the keto acids (66) with 4-alkoxydiphenylamines (75; R = CH3, C2H5) is widely used to prepare fluoran compounds developing green or black colors. The reaction in concentrated sulfuric acid gives intermediate phthalide compounds (76), which are then treated with base to convert into 2′-anilino-6′-aminofluorans (77) (Eq. 5). It is essential that the […]