Study On Anti-counterfeiting Principle And Characteirstics Of Spectrum-fingerpirnt Fiber

Rare-earth element has an unfilled and external shielded4f5d electronic configuration, over200thousand energy level transition channels and about30thousand spectral lines, on the basic of which, anew anti-counterfeiting principle was presented and an anti-counterfeiting fiber with spectrum-fingerprintcharactoristics was made. Under a special exciting light, this fiber had a corresponding emission spectralcurve, which is different from one to another, just like the fingerprint of human beings. And by detectingthe emission spectral curive of the fiber can be used to discriminate product identity. The security principleand charactoristics of spectrum-fingerprint fiber were studied deeply.Rare-earth luminescent material was the light emitting source of spectrum-fingerprintanti-counterfeiting fiber, presenting the emission spectrum properties of which was the premise andfoundation of investigating the security principle and characteristics of spectrum-fingerprint fiber. For thispurpose, in this paper, the emission spectrum properties of rare-earth luminescent material foranti-counterfeiting fiber application were studied. According to the applicability requirements of rare-earthluminescnet material of manufacturing spectrum-fingprint anti-counterfeiting fiber, rare-earth StrontiumAluminate luminescent material was selected and rare-earth Strontium Aluminate samples foranti-counterfeiting application were prepared and the effects of raw material formula and processparameters of rare-earth luminescent material on its emission spectrum were investigated systematically bymeans of XRD and Fluorescence spectrophotometer. The results showed that sintering temperature,theaddition of H3BO3,the doping of Eu2+and Dy3+and the A1/Sr ratios effected the emission spectra ofrare-earth Strontium Aluminate in various degree. It is a feasible way to make suitable rare-earth StrontiumAluminate luminescent material to meet the security needs through controlling parameters of process andformulation of raw materials of making rare-earth Strontium Aluminate.In order to seek theoretical support for analyzing the luminescent process, the structure and spectralproperties of spectrum-fingerprint fiber were studied and on the basic of which, the luminescent process ofthe fiber was simulatically analyzed. The results showed that the rare-earth Strontium Aluminateluminescent material particles were dispersed within the fiber frandomly, the complex manufacturingprocess did not destroy the phase of Strontium Aluminate in the fiber, and fiber components keeped a goodindependence each other. The spectral properties of spectrum-fingerprint fiber were similar to that ofrare-earth luminescent material dispersed in it, and the luminescence of spectrum-fingerprint fiber whenanti-counterfeiting detecting originates from rare-earth luminescent material dispersed in the fiber andbelongs to the timely characteristic luminescence of Eu2+ion of rare-earth luminescent material. Theluminescent of spectrum-fingerprint fiber was a complex process and was affected by fiber matrix,transparent inorganic pigment, exciting light source and so on.And then the effect elements of the spectral properties of spectrum-fingerprint fiber were investigateddeeply. In this paper, the effects of excitation condition on the spectral properties were studied by means ofFluorescence spectrophotometer through changing the excitation intensity and wavelength. The resultsshowed that the change of excitation condition had certain effects on the emission spectral curve ofspectrum-fingerprint fiber. Therefore in order to ensure the accuracy and uniqueness of the emissionspectral line of spectrum-fingerprint fiber, the measurement of emission spectrum must be conducted undera certain exciting light when the fiber was applied for identity discrimination. The effects of fiber matrix onthe spectral properties were studied by changing the type and content of fiber matrix to manufacture threedifferent spectrum-fingerprint fiber. The results showed that the content and type of polymer matrix hadlittle effect on the emission wavelength, but greatly on the emission intensity. Spectrum-fingerprint fiberwith different type and content matrix had different emission spectral curve with different intensity. Theeffects of transparent inorganic pigment on the spectral properties were studied by selecting five kinds ofand different content of transparent inorganic pigment to manufacture different spectrum-fingerprint fibers.The results showed that the addition of transparent inorganic pigment had no effect on the dispersion stateand phase structure of rare-earth luminescent material in spectrum-fingerprint fiber. However, transparentinorganic pigment influenced the excitation and emission process of spectrum-fingerprint fiber anddecreased its excitation and emission efficiency. The change of the type and content of transparentinorganic pigment both had much effect on the excitation and emission spectra of the fiber. The greater the degree of color interval between the color of transparent inorganic pigment and the emission wavelength ofrare-earth luminescent material was, the more obvious the shift to red or blue was. And the more thecontent of transparent inorganic pigment, the greater the degree of the effects. The effects of draw ratio onthe spectral properties were studied by changing draw ratio of spinning to manufacture differentspectrum-fingerprint fibers. The results showed that spectrum-fingerprint fibers with different draw ratiohad different emission spectral curves.Finally, the anti-counterfeiting application characteristics of the fiber were studied with the help offluorescence spectrophotometer. The results showed that the emission spectral curve ofspectrum-fingerprint fiber had good heat resistance, light resistance, waterproof property, durability andresistance to acid and alkali. But the emission intensity decreased after being stored and after being treatedby acide or base for long time meanwhile the emission wavelength had no change. Therefore the fibershould be stored in a dry environment and long-time erosion of acid and basic should be avoided inapplication.