Photostabilisation of colour formers for heat-sensitive recording systems: Effect of counter-ions on the photofading of fluoran dyes

Fluorans are given considerable attention as functional dyes for heat-and/or pressure-sensitive recording media. Numerous potential metal complexes were synthesised to prolong the life of coloured species. The protecting effect of these compounds against the photofading was examined on cellulose. It was found that the zinc or nickel salts of 3,5-dihydroxy-2-naphthoic acid and its derivatives can be applied as effective stabilisers against the fading of fluoran dyes.     

Protection of silica-coated ZnO nanoparticles on pre-dyed polyester fabrics against photofading

This work was designed to investigate the ability of silica-coated ZnO (ZnO&SiO₂) nanoparticles (NPs) as ultraviolet (UV) absorbers for protecting pre-dyed polyester fabrics against photofading. Despite that ZnO NPs are excellent UV absorbers, their strong photocatalytic activity limits the application in UV protection. In this study, a silica layer was coated onto ZnO NPs to form a physical barrier between the ZnO and a polyester substrate, which allowed effective UV shielding while minimising the harmful effects of photocatalytic activity on the substrate. The structure and optical proprieties of ZnO&SiO₂ NPs were observed. The bare ZnO and ZnO&SiO₂ NPs were, respectively, applied to polyester fabrics coloured with three kinds of dyes by a dip coating method. The photofading level of treated fabrics after exposure under simulated sunlight was evaluated. The ZnO&SiO₂ NPs exhibited excellent protection on pre-dyed polyester fabrics against photofading.     

一种铟酞菁染料的吸收光谱及其光褪色现象研究

对一种可望应用于 6 94nm激光防护的铟酞菁染料 (InPc) ,利用玻璃模具制备了铟酞菁掺杂高分子聚甲基丙烯酸甲酯和聚碳酸酯薄膜。研究了该染料的氯仿溶液和薄膜吸收光谱 ,并分析了电子结构 ,同时推导了溶液中的光褪色机理。研究表明 ,在实验溶液浓度范围内InPc以单体形式存在 ,6 94nm处的吸收强度和窄吸收峰形符合激光防护的要求 ,而InPc薄膜 Q 带出现两个吸收强度大致相等的峰 ,吸收波长较溶液光谱有少量蓝移或红移 ,吸收带增宽 ,且在不同高分子体系中获得相同吸光强度的薄膜所需染料的量明显不同 ,这主要是由于染料分子发生光降解和聚集态不同而使薄膜光谱特点复杂化。同时 ,通过对褪色产物分析探讨了该染料分子在氯仿溶液中可能发生的光降解断裂方式     

Effect of uv absorbers containing singlet oxygen quenching groups on the photochemical stability of crystal violet lactone and related colours

The photofading behaviour of Crystal Violet Lactone was investigated in solution. The contribution of singlet oxygen to that fading was suggested. UV absorbers containing nickel sulphonate quenching groups were prepared and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined in solution and in solid state. It was proposed that nickel salts of 2,2′-dihydroxy-4,4′-dimethoxybenzophenone-5-sulphonic acid and its derivative can be applied as effective stabilisers against the photofading of indicator dyes in pressure (or heat) sensitive recording systems.     

Effect of Dye‐Bath pH on Photostability of Dyed Nylon 66

Nylon 66 films were dyed in aqueous dye‐bath with C. I. Acid Blue 25 (1‐amino‐4‐(aminophenyl)‐2‐anthraquinone sodium sulfonate) at various pH values ranging from 2.0 to 7.0. Films were exposed to polychromatic irradiation (λ ⪈ 290 nm) at 60°C in air. The extent of photo‐oxidation was monitored by FT‐IR spectroscopy. Fading of dye with polychromatic irradiation was monitored by UV spectroscopy. We observed a peculiar effect of dye‐bath pH on the photostability of dyed nylon 66. Samples were more stable when dyed at pH 3 and above that (up to pH 7), whereas the samples dyed at pH < 3.0 showed sensitized photo‐oxidative degradation in nylon 66. Formation of quaternary ammonium salt on dye‐chromophore was considered responsible for the pH‐controlled behavior of anthraquinone acid dyes. The dyeing pH significantly effects the photofading behavior of dyed samples. The effect of dye‐bath pH on photofading of the dyed samples was more pronounced at lower dyeing pH and prevailed up to pH 4. The hydronium ion concentration was considered to be responsible for the enhanced fading of dye for the samples dyed at the lower pH.     

添加剂对酸性橙7水溶液光褪色的影响

本文研究了添加剂对酸性染料酸性橙７水溶液光褪色的影响．二氨基蒽醌一般能抑制褪色,这是由于二氨基蒽醌对水中生成的单线态氧产生湮灭作用;环糊精抑制褪色,是由于其包接作用使染料的偶氮基团被保护起来;二氧化钛能显著促进光褪色,是由于它的光催化作用．     

用荧光光谱法研究染料与氧的作用机制

研究了孟加拉玫瑰红（ＲＢ）和品红甲亚胺染料与氧的作用机制．结果表明，氧对ＲＢ的荧光猝灭是能量转移、电子转移、以及对其激发单线态和激发三线态猝灭的综合作用结果，呈现偏离正常的Ｓｔｅｒｎ－Ｖｏｌｍｅｒ直线关系．氧与品红甲亚胺染料的作用，出现荧光量子产率增大的现象，可能是形成了接触电荷转移激态络合物，由它转换生成单线态氧和超氧负离子自由基的能力极低     

偶氮染料结构与日晒牢度关系研究

本文介绍了近年来国内外对于偶氮染料光致褪色的研究进展,综述了偶氮染料光褪色与偶氮键断裂机理。利用Hammett方程,反映出取代基效应与染料褪色速率间的定量关系,并将Hammett方程引入分散、酸性偶氮染料日晒牢度的分析中,很好的阐释了取代基团吸、供电子效应对染料在不同纤维上日晒牢度的影响,并提出了获得优异日晒牢度染料的合成和应用方法。     

有机染料光褪色机理及主要原因

本文综述了有机染料光褪色机理的主要研究方法以及现有研究结论．对光氧化和光还原过程、影响因素、典型反应步骤、研究手段进行了系统的阐述，同时也对通过染料分子结构设计合成、通过添加剂的使用提高染料光牢度的方法进行了介绍．     

湿革干燥时染料发生光退色的原因分析

对染色湿革在干燥过程中发生光退色的原因进行了分析 ,在此基础上提出了相应的预防措施