Hironori Oda

Photostabilisation of colorants for imaging and data recording systems : effect of metal carboxylates on the lightfastness of colour formers

Abstract Metal complexes of hydroxycarboxylic acids or dicarboxylic acids were prepared and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined on cellulose. It is proposed that nickel or zinc salts of 1-hydroxy-2-naphthoic acid and its derivatives can be applied as effective stabilisers against the photofading of indicator dyes in pressure- (or heat-)sensitive recording systems. These metal carboxylates were also found to improve the image stability of the indicator dyes.

An approach to the photostabilization of dyes: the effect of UV absorbers containing a built-in photostabilizer moiety on the light fastness of acid dyes

The photofading behaviors of some acid dyes were investigated in polymer substrate. The contribution of singlet oxygen to those fadings was suggested. Various phenyl ester type UV absorbers were prepared, and the protecting effect of these compounds towards the photofading of acid dyes was examined in cellulose acetate film. It was proposed that nickel complexes of 4-benzoyloxybenzenesulfonic acid and its derivatives can be applied as effective stabilizers against the fading of indicator dyes for printing and imaging systems.

New developments in the stabilization of photochromic dyes: Counter-ion effects on the light fatigue resistance of spiropyrans

Abstract Photochromic spiropyrans have attracted much current attention because of their potential applications including optical memories and light-controlling media. The colored form of the compound, however, is thermally unstable and bleached. Numerous potential metal complexes were synthesized to prolong the life of colored species. The protecting effect of these compounds against the decoloration reaction in the dark or photofading of photocolored species was examined on cellulose. It was found that the spiropyran in the presence of zinc 1-hydroxy-2-naphthoate or its derivatives shows excellent light fatigue resistance.

Photostabilisation of photochromic materials: contribution of amphoteric counter-ions on the photostability of spiropyrans and related compounds

Abstract Photochromic Spiropyrans are receiving considerable attention as functional dyes for reversible image recording medium. Metal complexes of hydroxycarboxylic acids or dicarboxylic acids were prepared to prolong the life of coloured species. The protecting effect of these compounds towards the photofading or dark decay reaction of photocoloured species was examined on cellulose. It was found that zinc salts of 1-hydroxy-2-naphthoic acid and its derivatives are very effective for stabilising the coloured form of spiropyran and related compound.

Role of counter-ions in the photofading reaction of crystal violet lactone

Abstract The photofading behaviour of Crystal Violet lactone was investigated in solution and in the adsorbed state and the contribution of dye counter-ions to the fading is demonstrated. A novel approach for improving the lightfastness of indicator dyes in pressure (or heat)-sensitive recording systems is proposed.

The effect of hydroxyarylbenzotriazoles containing a singlet oxygen quenching moiety on the photofading of dyes on a polymer substrate

Numerous potential UV absorbers were synthesized to prolong the life of colorants for printing and imaging systems. The effect of these compounds in reducing photofading was examined on a polymer substrate. The use of a simple UV absorber was not necessarily useful in improving the light fastness of the colorants. Nickel hydroxyphenylbenzotriazolesulfonates, however, markedly suppressed the photofading rate of a triphenylmethane dye. The fading of an xanthene dye was completely depressed in the presence of nickel 2-(5-methyl-2H-benzotriazol-2-yl) naphthol-4-sulfonate. It is proposed that nickel complexes of hydroxyphenylbenzotriazolesulfonic acid and its derivatives may be used as effective stabilizers in the fading of indicator dyes for printing and imaging systems.

Influence of metal quinolinecarboxylates on the image-stability of colorants for information recording systems

Metal complexes of carboxylic acids were prepared, and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined on cellulose. It was proposed that nickel or zinc salts of 8-hydroxyquinoline-2-carboxylic acid and its derivatives can be applied as effective stabilisers against the photofading of indicator dyes in heat- (or pressure-) sensitive recording systems. These metal carboxylates were also found to be very useful for stabilising the coloured form of spironaphthoxazine.