RETROREFLECTIVE SHEET MANUFACTURING METHOD

摘要

A retroreflective sheet manufacturing method having the steps of placing a light-permeable protective film on glass beads in a support sheet which consists of a binder layer and a reinforcing layer, and which is provided with retroreflective glass beads buried in the binder layer, and thermally deforming parts of the support sheet under heating and pressure so as to partially bond the binder layer of the support sheet to the protective film, characterized in that the reinforcing layer of the support sheet consists of a cross-linked resin having shearing stress S in the range of 6x10<6>-1.2x10<7> dyne/cm<2> before the thermal deformation of the support sheet has been carried out. A retroreflective sheet manufactured by this method has a high uniformity of the joint portions of the support sheet and protective film. Even when this retroflective sheet is used outdoors for a long period of time, troubles including the separation of the protective film do not substantially occur. This retroreflective sheet can be utilized extensively as a road sign board, a license plate for a vehicle, a sign board for construction work and an advertisement board.