METHOD FOR PRODUCING A PERFORATED INTEGRAL STACK OF POLYCARBONATE SHEETS

摘要

The proposed invention relates to a method for creating forgery-protected integral stacks of polycarbonate sheets in order to produce various valuable documents, by means of applying perforated images thereto with the goal of complicating the possibility of counterfeiting the given product and decreasing the number of defective integral stacks of polycarbonate sheets. The method includes forming a stack from individual polycarbonate sheets having a thickness of 50-100 micrometers, connecting same in order to form an integral stack, and perforating a certain area of the integral stack by means of laser radiation. Positioning a stack between two rigid parallel plates, heating the formed stack in stages, from room temperature to the temperature at which polycarbonate becomes soft, holding the stack, during each stage, at predetermined temperatures and compressing for 10-15 seconds in order to level and stabilize the temperature gradient on the entire plane of the field of the stack, and simultaneously, at each subsequent stage, increasing the value of the compression acting upon the assembled stack. Holding the stack, during the final stage, in a compressed state, until an integral stack having a thickness of 500-1000 micrometers is formed, cooling the formed integral stack together with the plates until room temperature is reached, freeing the stack from the plates and positioning the stack vertically between two parallel frames, and perforating a certain area of the integral stack comprised of individual polycarbonate sheets by means of laser radiation in a working field delimited by the frames.