GB542085A - Improvements in and relating to transparent or translucent screens made from plastics - Google Patents

Abstract

542,085. Cellulose-derivative and synthetic resin articles. FEJER, G. June 22, 1940, No. 10770. [Classes 2 (ii) and 2 (iii)] [Also in Groups VIII and X] A light-transmitting screen made from a translucent or transparent plastic comprises at least one element having a plane flat surface and cell- or channel-forming means moulded together or extruded or formed integral by autogenous jointing, preferably under heat and pressure. Autogenous jointing includes the use of an adhesive of the same genus as the plastic. Suitable plastics are cellulose acetate, cellulose butyrate, ethyl cellulose, and polyvinyl or polyacrylic resins. As shown in Figs. 1 and 2 an inner corrugated sheet of cellulose acetate 3 is adhered by the apices of the corrugations to two outer flat sheets 1, 2. The cells may be flattened by pressure traverse to, as at 4, or longitudinally of the corrugations. Such flattened portions may be used to connect units by securing overlapping parts by adhesives or by bending over to form interengaging hooks. Inter-communicating channels may be formed by shaping the inner sheet 10 as shown in Fig. 5. Closed cells may be formed by perforating the inner sheet 12 to form apertures 13 as shown in Fig. 6. Screens may be secured together face to face by adhesive or by tape or strip binding round the edges, or to glass sheets by adhesive or by means of their flattened edge portions. Where two screen units are to be secured to a larger area of glass adjacent flattened portions are received in channel-shaped cellulose acetate strips which may be directly secured to the glass by adhesive or with the aid of an adhesive-coated fabric strip. The screens may be applied to the underside of pavement lights or glass tiles by bedding the flattened margins together with the glass in the channels of the supporting frame. Reference has been directed by the Comptroller to Specification 528,545, [Group VIII].