열프레스 성형법을 이용한 재귀반사시트 제조에 관한 연구

Abstract

Prismatic reflective sheets were manufactured with microprisms, and their retroreflection and structural properties were examined and compared with encapsulated lens type reflective sheets in terms of glass beads. As manufactured, the prismatic reflective sheets demonstrate well aligned arrangement of microprisms. The array of glass beads in encapsulated lens type reflective sheets is also found to be uniform without any cracks. However, during the coating process of the PET layer, the beads are turning out and the gaps are formed ascribed to the application of high pressure. It shows that the retro reflectance of all retro reflective samples at low incident angle with respect to the perpendicular is better than at high angles. At high incident angles, the glass beads are slightly better than prisms. Even though the preparation method for reflective sheets based on microprisms is similar to that of reflective sheets based on glass beads, the method is relatively simple and cost effective, and also needs less time. Prismatic reflective sheets show higher coefficient of retroreflection from all entrance angles compared to reflective sheets based on glass beads. The results prove that the prismatic reflective sheets can be used for preparing the traffic sign boards to secure a clear view and be more cost-effective method.