Preparation And Theoretical Research Of Glass Beads Retro-reflective Fabrics

Retro-reflective materials have been widely used because of good retro-reflection in the fieldof road traffic, special operating garments, fire protection, mining and other safety signs. Thevisibility of the dark environment can be enhanced because of its excellent retro-reflection, thus itis very important to keep lives safety. Retro-reflective fabrics are used more widely in recentyears.This thesis focuses on the effect of glass beads and preparation on retro-reflective fabrics.According to the principle of retro-reflection, the influence of diameter and refractive index of aglass bead, on deflective angle and retro-reflection was firstly analyzed. Then the influence of theconditions of preparation for retro-reflective fabrics with glass beads on retro-reflection werediscussed, as well as other properties of retro-reflective fabrics. Theoretical method, experimentanalysis and the combination of them were used to analyze the data in this dissertation.When discussing the influence of retro-reflection of a single glass bead, preparation conditionand factors of retro-reflection were theoretically analyzed by optical path tracing method.Especially, several factors of a glass bead were used to analyze the deflective angle ofretro-reflection, including refractive index, diameter and angle of incident light. Deflective anglewas existed when retro-reflection occurred. It was inevitable because it could be regarded asobservation angle of retro-reflection, as well as the important parameter in the application ofpreparation and measurement. In addition, the models of glass beads with low refractive indexwere discussed. The preparation for the retro-reflective fabrics was proposed accordingly, whichincreased a spacer layer with a certain thickness in order to reduce the deflection angle.Concentrated retro-reflection could be obtained in these models.It was discussed that the factors of preparation methods and the ratio of the concentration forretro-reflective fabrics which affect the retro-reflection in the experiments of the dissertation.Firstly, the comparison of sprinkling bead method and coating method for preparation for retro-reflective fabrics was analyzed according to coefficient of retro-reflection, morphology ofsurface and section, coating thickness, changes of mass and friction fastness. Actually, there mustbe a distribution of particle size in glass beads, because it was regarded as a kind of particulatepowder and uniform size of the particle could not exist. Therefore, size distribution analysis ofglass beads was essential. In the context of the particle size distribution, retro-reflective fabricswere prepared according to the corresponding requirements. It has been shown that preparationmethods and the diameter of glass beads have an influence on retro-reflection coefficient ofreflective fabrics by data testing and analyzing, as well as the surface distribution of glass beads,surface coverage of glass beads on the fabrics, coating thickness, changes of weight per unit areaof retro-reflective fabrics, friction property. During comparing the preparation methods, stabilityproperties were considered; coating method was used to discuss the influence of differentconcentrations of mass ratio on the properties of retro-reflective fabrics.When different factors were analyzed, there are several factors that have greater effect onretro-reflection property, which included the diameter and size distribution of glass beads, thenumber of glass beads and the covered area on the surface of retro-reflective fabrics. It showedthat when glass beads with large diameter in a certain range and large surface covered area, highcoefficient of retro-reflection could be obtained and retro-reflection property was improved.