Patent GB-893333-A (GB)
Title: Heat glossing compositions and recording elements
IPC: G03G5/05
Filed: 1958-05-20
Abstract: A recording medium comprises a support member or sheet and a coating thereon, the coating including a particulate pigment, a thermoplastic vehicle for the said pigment and a low melting material, said low melting material having a melting point lying between 75 DEG  C. and 200 DEG  C. and being insoluble in the vehicle and present in an amount of some 1,2% to 20% by weight of the coating, the vehicle having a softening point not more than 100 DEG  C. above the said melting point and the vehicle and low melting material being present in separate phases and with the pigment suspended in the vehicle and protruding above the surface for providing a matt finish surface suitable for being written, drawn or printed upon in a normal manner by marking the surface locally with a deposit of pencil lead, crayon, ink, or other marking material and said surface being suitable for being thereafter converted by application of heat to a glossy finish surface.  The support material may be metal such as iron, copper, aluminium or silver, or wood, glass, ceramic or mineral material.  It may be in the form of a sheet, web or foil or may be massive. Suitable pigments include titanium dioxide, stannic oxide, zinc sulphide, zinc oxide, iron oxide and cadmium sulphide-zinc sulphide fluorescent pigment.  In particular where the surface is to be used for electrostatic printing a photo-sensitive zinc oxide may be included.  The low melting material may be a calcium, aluminium, magnesium or zinc stearate, 12-hydroxy stearin, Carnauba wax, mixrocrystalline wax, polymerized petroleum resin or synthetic resins based on styrene or acrylic esters.  Suitable vehicles include polymerized petroleum resins and synthetic resins based on styrene and acrylic esters.  Dyestuffs and tricresyl phosphate may also be added to the coating composition. The recording medium may be prepared either by a single stage process in which the vehicle is dissolved in the solvent and the low melting material and the pigment are suspended in this solution, the whole then being applied to the surface and the solvent thereafter removed at temperatures below the glossing temperature of the coating.  Alternatively a two-stage process may be used in which the low melting material is first applied to the support and thereafter a suspension of the pigment in a solution of vehicle in the solvent is applied to the surface.  In use, matter is written on the surface either in the ordinary way or by means of electrostatic printing and the surface is then heated under an infra red lamp or in an oven to for example 180 DEG  C. for a short time, whereupon the recording medium is provided with a glossy surface and fixed in such a way as to render subsequent erasure and further additions difficult if not impossible.ALSO:A recording medium comprises a support member or sheet and a coating thereon, the coating including a particulate pigment, a thermoplastic vehicle for the said pigment and a low melting material, said low melting material having a melting point lying between 75 DEG C. and 200 DEG C. and being insoluble in the vehicle and present in an amount of some 1,2% to 20% by weight of the coating, the vehicle having a softening point not more than 100 DEG C. above the said melting point and the vehicle and low melting material being present in separate phases and with the pigment suspended in the vehicle and protruding above the surface for providing a matt finish surface suitable for being written, drawn or printed upon in a normal manner by marking the surface locally with a deposit of pencil lead, crayon, ink or other marking material and said surface being suitable for being thereafter converted by application of heat to a glossy finish surface.  Suitable pigments include titanium dioxide, stannic oxide, zinc sulphide, zinc oxide, iron oxide and cadmium sulphide-zinc sulphide fluorescent pigment.  In particular where the surface is to be used for electrostatic printing a photo sensitive zinc oxide may be included.  The low melting material may be a calcium, aluminium, magnesium or zinc stearate, 12-hydroxy stearin, Carnauba wax, microcrystalline wax, polymerized petroleum resin or synthetic resins based on styrene or acrylic esters.  Suitable vehicles include polymerized petroleum resins and synthetic resins based on styrene and acrylic esters.  Dyestuffs and tricresyl phosphate may also be added to the coating composition.  The recording medium may be prepared either by a single stage process in which the vehicle is dissolved in the solvent and the low melting material and the pigment are suspended in this solution, the whole then being applied to the surface and the solvent thereafter removed at temperatures below the glossing temperature of the coating.  The coating composition of Example 9 consisted of zinc oxide, Petronauba wax, silicone resin, xylene and toluene.