FIELD: decorative art.
SUBSTANCE: method of stamping optical diffracting microstructures in a thin foil of the type used in packages of at least one of the objects of the group including food products, chocolate, chewing gum, souvenirs, jewellery, clothes, tobacco products and pharmaceutical products, by means of a set of embossing rolls, containing one or more cylindrical embossing rolls and a bombed counter-wipe. Method involves following operations: placing one or more cylindrical embossing rollers and a bombed counter-wipe into a single roller stand with relatively small outer dimensions, capable of withstanding pressure, applied to one or more cylindrical embossing rolls and to bombed counter-wipe; one or the first cylindrical embossing rollers is used, having on its surface (2) one or more convex embossing elements (1), adapted for embossing the microstructure, wherein one or one of said convex embossing elements comprises platform 5 arranged at distance 5–30 m from said surface of single or first cylindrical embossing roller and provided with pattern engraved on its surface. Pattern comprises microstructures of the grating type with a period of less than 30 mcm, which form the diffuse images of the source of diffuse or directed light in the visible range, having high contrast and high brightness for a given viewing angle, and setting pressure applied to thin foil by platform with area of about 100 mm2, which is available on at least one cylindrical embossing roller, which is less than 8 MPa.
EFFECT: relatively low embossing forces and pressures at room temperature to avoid pre-heating.
8 cl, 70 dwg
