| Ultraviolet ray is an electromagnetic wave radiation (Ultraviolet radiation,UVR). According to the band, it can be divided into nearly Ultraviolet (UVA), farUltraviolet (UVB) and ultra short Ultraviolet (UVC), responding to the band320-400nm,280-320nm and100-280nm, respectively. Normally, UVC can be absorbed by theozone layer in the atmosphere, part of the UVA and UVB will also be absorbed bythe ozone layer, only a few Ultraviolet radiations can reach the surface of theearth. However, in recent years, due to the high speed development of economy inthe human society, the ozone layer is becoming thinner and thinner and the localarea appears ozone hole.Ultraviolet ray, which reaches to the fabrics, are absorbed partially by nature.Another one is reflected by fiber surface, the rest is through the fabric,undoubtedly, these ultraviolet rays have a disastrous effect on the skin, causingskin damage and producing lesions. UV protection method and principle are asfollows: the fiber, yarn and fabric were modified using UV shield agent or otherfunctional additives, so as to achieve the purpose of ultraviolet absorption orreflection. Or the fabrics are treated using inorganic ultraviolet lightscattering agent and/or organic ultraviolet ray absorber. By the immersion,printing or absorption process, the agents attach to the surface of the fabricsor yarns and then the ultraviolet prevention fiber and fabric can be produced.At present, there is no unifying definition for light conversion agent, thenaming are also different. Usually, light conversion agent is a kind of chemicalmaterial, which can transform ultraviolet light into red, green and blue light.Their core is the rare earth elements, such as Eu and Sm. Due to their unique f-frail electronic transition, they can send out features light, with the functionof conversion from ultraviolet to red, blue or green light. In addition, some fluorescence inert of rare earth elements, such as yttrium (Y), are bonded withfluorescence active ions, can play a fluorescence enhancement effect.Rare earth organic light conversion agent is a kind of organic complexconsisted of Eu or miscellaneous nuclear rare earth elements. They can absorbultraviolet light and launch out of visible light. Because they have the advantagessuch as high lighting brightness, excellent light color oneness, strong stability,good ageing resistance and easy to spread to all kinds of solvent and organicmaterials medium, it is especially suitable to make all kinds of organicfluorescent materials.Using the light conversion function of light conversion agent, ultravioletlight are conversed effectively, which can reach the purpose of preventingultraviolet ray. This will expand the application area of rare earth, especially,it has an important meaning for the development of functional textile, and yet.However, such researches have not been found. In this topic, we first studied thefeasibility of light conversion agent used as UV finishing agent of textiles, andthen the new light conversion agent were synthesized. Subsequently, the influenceof synthesis process such as the different ligands and synthetic route on theability of light conversion was then analyzed. Finally, the dispersion of the lightconversion agent was studied. According to the absorption capability of UV lightand the absorption wave band, we selected the ideal light conversion agent, whichcan absorb a broadband ultraviolet light effectively. Since then, the finishingprocess with different light conversion agent and the changes of the fabrics beforeand after finishing were studied.The results showed that the sold rare earth complexes light conversion agentcan absorb300-360nm ultraviolet light and launch591.8,614.1,701.8nm red,yellow light. The UV protection ability of the fabrics finished by the lightconversion agent obviously increased. This verified the feasibility of lightconversion agent used as fabric UV finishing agent. However, we also found thatlight conversion agent in the water was not easy to dissolve and disperse. Thiswill cause the color difference.In the synthesis of new light conversion agent, we found, through the solid phase synthesis methods, Eu carbonate and organic ligand could grinded togetherinto complexes such as Eu (sds)4, Eu (q)4, Eu (AcA)4, Eu (DBM)4, Eu (TTA)3phen,Eu (sal)3sds and Eu (DBM)3q, respectively. Chlorinated Eu was first dissolved inethanol, through the liquid synthesis process, Eu and TTA, phen can get rareearth Eu (TTA)3phen complex. Compared with Eu (TTA)3phen complex synthesizedthrough the solid phase, the characteristic peak of the complex synthesized inthe liquid phase was clearer. Additionally, the characteristic peak of the liganddisappeared, suggesting that the bonding between Eu and the ligand in the liquidwas tighter than the one in the solid phase. From the excitation spectra of newsynthetic rare earth organic complexes, due to the introduction of organic ligand,the absorption band was not similar for different complexes. However, because ofelectron transfer function of organic ligands, these complexes generally couldabsorb200-400nm UV ray. The absorption band could be up to200-450nm forEu (DBM)4complexes. In comparison of the excitation spectrum of severalcomplexes, we could find that the UV absorption of the complex with two ligandswas higher than the complex with one ligand. Eu (TTA)3phen, which had two ligands,could absorb UV ray with the band from200nm-400nm. Furthermore, the absorptionvibrating peak of Eu (TTA)3phen was wider and higher than the complexes such asEu (sds)4, Eu (q)4, Eu (AcA)4, Eu (DBM)4, suggesting that it had a strongerabsorption capability.In the analysis of dispersion, we found that the dispersion ability of sodiumhexametaphosphate was significantly better than sodium polyacrylate. Three kindsof decentralized system, the better concentration was1.5g/L for sodiumhexametaphosphate and sodium polyacrylate, but the concentration of2.5g/L wasideal for the composite dispersant (sodium hexametaphosphate to sodiumpolyacrylate was1:1). Through the absorbency analysis, we could also obtain thesame results. We found that, type A light conversion agent that could dissolvein the ethanol had the best dispersion, Type C was the worst. The addition ofdispersant improved the dispersion performance in varying degrees, and with theincrease of the concentration of dispersant, the absorbency first increased and then decreased. The best decentralized process was follows: the concentration oflight conversion agent1g/L, the concentration of sodium hexametaphosphate1.5g/L, and stirring in high speed.When light conversion agent was used alone, the concentration1.0g/L couldobtain the best ultraviolet protection effect. The finishing process of bakingwas better than the other processes such as natural drying and padding. The additionof dispersant could increase the UV protection ability. The concentration of thedispersant in the finishing process was similar with the one in the dispersionresearches. The ultraviolet protection effect of Eu (TTA)3phen was the best. Afterfinishing by light conversion agent, the wrinkle recovery and the strength hadno significant change, but the white degree demonstrated a slight decline,additionally, DATACOLOR SF-60testing results showed that the fabric finished bylight conversion agent turned red and green light.To sum up, we can find that light conversion agent can be used as fabric UVprotection finishing agent. They have the absorption ability of broad bandultraviolet light. The UV resistance of the fabric finished by light conversionagent obviously improved, but it just needs less dosage, which provides a newassistant for the UV protection finishing. This can reduce the cost and the process.In addition, this provides important reference for the effective use of rare earthand its application expansion.
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