Abstract: An object of the present invention is to provide a light reflector plate having the following advantages A to D: A. no need for high initial investment for dies or the like required for forming a three-dimensional shape; B. simple working and low cost of working; C. accurate shape retention of a reflector plate after bending work, and excellent dimensional stability even under severe conditions of use; and D. simple and low-cost attaching work for shape retention. To achieve the above object, according to the present invention, narrow cuts 4 are intermittently formed in a light-reflecting plastic foam film or sheet 2 along straight lines in such a manner as to penetrate from one side surface of the film or sheet 2 to the opposite side surface thereof. Subsequently the film or sheet is bent along the cuts.

Abstract: There are provided a method and an apparatus for continuously manufacturing a cross-linked thermoplastic resin foam arranged as follows. A resin composition, which contains at least a thermoplastic resin, a foaming agent, and a cross-linking agent, is extruded into a closed die, which includes at least a molding region, a heating region, and a cooling region, continuously arranged in the order named. The resin composition is molded into a desired shape in the molding region of the die, and is then heated in the heating region to decompose the cross-linking agent and also to decompose at least part of the foaming agent so that cell nuclei are produced, thereby forming a partially foamed product. In the cooling region of the die, the partially foamed product is cooled to a temperature lower than the softening point thereof to be increased in rigidity, and is extruded to the outside of the die while being subjected to a damping force as it moves in the cooling region.