GB261772A - Improved process of manufacture of substances having a nacreous, pearly or chatoyant aspect and apparatus therefor - Google Patents

Abstract

261,772. Paisseau, J. Nov. 21, 1925, [Convention date]. Addition to 207,144, [Class 70, India-rubber &c.]. Extrusion presses; moulds; moulding artificial mother-of-pearl; pressing-plungers; pipes and tubes.-The process of the parent Specification wherein a mass containing brilliant particles is so formed as to draw the particles parallel to one another, is modified to ensure that all the particles are oriented into parallel planes, so that the sheets obtained are uniform in appearance over their whole surface. This may be done in an extrusion press, Fig 5, the necessary conditions being that the mass must be sufficiently plastic and the pressure applied regularly without shock, the nozzle 5 must be free from irregularities and shaped to prevent the formation of eddies, and the brilliant particles must be uniformly distributed throughout the mass. Another method of producing the same result is shown in Fig. 11, in which the mass is pressed between spring-held side plates 7 by a piston 10, 11, capable of expanding. 'Other methods described comprise extruding the mass through an annular die, the central member of which is held by studs shaped to prevent eddies, and cutting the tube longitudinally as it emerges, and moulding the mass in an annular press having extensible walls by applying radial pressure to the interior wall. When sheets are pressed into blocks, the sheets should be of such a size as to fill the mould without any space being left between the edges of the sheets and the sides of the mould.