Abstract: A light reflection material comprises transparent body of organic glass having therein a thin through hole or holes whose inner wall is smooth. This material is useful for an ornamental material, a lighting material, eye-obstructing material, shading material, etc.This material is manufactured by pouring a raw material into a mold within which a thread or threads of synthetic fiber are straightly or curvedly set according to aimed pattern and pulling the thread or threads out of the formed body to form a thin hole or holes or pulling the thread or threads to separate them from the inner wall of the hole or holes. As a result of it, a hole or holes of a shape and number corresponding to those of the thread or threads are formed in the formed body.

Abstract: A stamped plastic sheet manufacturing method includes immersing a molten extruded thermoplastic sheet into a liquid refrigerant just prior to passing through a pair of stamping rolls having tooth-like or vane-like projections. In this manner, a skin layer is formed on the surface of the molten plastic sheet prior to stamping. Upon stamping, the sheet is tensioned by the confronting crests of the above tooth-like or vane-like projections and then removed from the liquid refrigerant after the interior of the sheet has been hardened to form a stamped sheet having a substantially uniform thickness.