Security Paper Comprising Windows

Abstract

The invention relates to a security paper for the production of documents of value which comprises a flat cellulose-containing substrate with a polymeric window included therein, to processes for the production of a security paper of this type and to the use thereof for the production of documents of value.

1 . Security paper for the production of documents of value, comprising a flat cellulose-containing substrate with at least one polymeric window included therein. 
     
     
         2 . Security paper according to  claim 1 , where the window is transparent or semitransparent. 
     
     
         3 . Security paper according to  claim 1 , where the cellulose-containing substrate and/or the polymeric window have optically variable properties. 
     
     
         4 . Security paper according to  claim 1 , where the polymeric window has light-polarising properties. 
     
     
         5 . Security paper according  claim 1 , where the polymeric window is a moulding of core/shell particles which have a polymeric shell. 
     
     
         6 . Security paper according to  claim 1 , where the cellulose-containing substrate comprises core/shell particles which have a polymeric shell. 
     
     
         7 . Security paper according to  claim 1 , where the shell of the core/shell particles forms a matrix in the window, and the cores are essentially solid and dimensionally stable and have an essentially monodisperse size distribution. 
     
     
         8 . Security paper according to  claim 1 , where the cellulose-containing substrate comprises core/shell particles whose cores are essentially solid and dimensionally stable and have an essentially monodisperse size distribution. 
     
     
         9 . Security paper according to  claim 5 , where the core material and shell material of the core/shell particles have different refractive indices. 
     
     
         10 . Security paper according to  claim 5 , where the core is chemically bonded to the shell via an interlayer. 
     
     
         11 . Security paper according to  claim 5 , where the weight of the shell is identical to or greater than the weight of the core. 
     
     
         12 . Security paper according to  claim 6 , where core/shell particles are present in and/or on the cellulose-containing substrate. 
     
     
         13 . Security paper according to  claim 1 , where the cellulose-containing substrate is a security paper which comprises predominantly cellulose from vegetable fibres and/or rags. 
     
     
         14 . Security paper according to  claim 13 , comprising cellulose fibres from cotton. 
     
     
         15 . Security paper according to  claim 1 , where the cellulose-containing substrate is an unsized or sized paper. 
     
     
         16 . Security paper according to  claim 5 , where the shell of the core/shell particles consists of a material which becomes flowable through an increase in pressure or pressure and temperature. 
     
     
         17 . Security paper according to  claim 5 , where the core of the core/shell particles consists entirely or predominantly of an organic polymeric material which is either non-flowable or is flowable at a temperature above the melting point of the shell material. 
     
     
         18 . Security paper according to  claim 5 , where the core of the core/shell particles consists entirely or predominantly of an inorganic material. 
     
     
         19 . Security paper according to  claim 5 , where the difference between the refractive indices of the core material and shell material is at least 0.01. 
     
     
         20 . Security paper according to  claim 19 , where the difference between the refractive indices is at least 0.1. 
     
     
         21 . Security paper according to  claim 10 , where the interlayer is a polymeric interlayer or a surface functionalisation of the core. 
     
     
         22 . Security paper according to  claim 5 , where the core and/or shell of the core/shell particles additionally comprises at least one contrast agent. 
     
     
         23 . Security paper according to  claim 5 , where the core/shell particles have particle diameters of 50 to 800 nm. 
     
     
         24 . Security paper according to  claim 11 , where the core/shell particles have a core:shell weight ratio in the range from 1:1 to 1:5. 
     
     
         25 . Security paper according to  claim 11 , where the weight of the shell of the core/shell particles is greater than the weight of the core. 
     
     
         26 . Security paper according to  claim 1 , which has at least one further security feature in addition to the polymeric window. 
     
     
         27 . Security paper according to  claim 26 , where the additional security features are watermarks, planchettes, fibres, security threads, fluorescent dyes, infrared- or UV-active dyes, magnetic particles, electrically conductive particles, optically variable pigments, optically variable layers, optically variable prints, liquid-crystalline coatings, holograms, kinegrams, diffractive pigments, RFID elements, laser marks, chemical additives which become visible on illumination at certain wavelengths or on manipulation, microtexts, guillochés and the like. 
     
     
         28 . Security paper according to  claim 27 , where the laser mark is located on the polymeric window. 
     
     
         29 . Process for the production of a security paper according to  claim 1 , in which core/shell particles which have a shell of polymeric material are introduced into an aqueous cellulose-containing paper pulp and, together with further paper raw materials, converted into a paper sheet, and the paper sheet is provided with at least one cut-out for a window, in which elevated pressure or elevated pressure and elevated temperature are allowed to act on the paper sheet in such a way that at least some of the core/shell particles present in the paper sheet are pressed into the cut-out so that the core/shell particles fill the cut-out, and in which the shell of the core/shell particles forms a matrix, at least in the cut-out and in an edge zone between cut-out and paper sheet. 
     
     
         30 . Process for the production of a security paper according to  claim 1 , in which core/shell particles which have a shell of polymeric material are introduced into an aqueous cellulose-containing paper pulp and, together with further paper raw materials, converted into a paper sheet, and the paper sheet is provided with at least one cut-out for a window, and in which core/shell particles having a polymeric shell are applied to the cut-out in the paper sheet so that the core/shell particles fill the cut-out, and in which elevated pressure or elevated pressure and elevated temperature are allowed to act on the paper sheet in such a way that the shell of the core/shell particles forms a matrix, at least in the cut-out and in an edge zone between cut-out and paper sheet. 
     
     
         31 . Process according to  claim 29 , in which the core/shell particles are introduced into the paper pulp in an amount of 0.1 to 50 per cent by weight, based on the dry weight of the paper. 
     
     
         32 . Process according to  claim 30 , in which the core/shell particles introduced into the paper pulp and the core/shell particles applied to the cut-out are identical or different. 
     
     
         33 . Process according to  claim 29 , in which a predominantly aqueous dispersion of core/shell particles is employed. 
     
     
         34 . Process for the production of a security paper according to  claim 1 , in which core/shell particles which have a shell of polymeric material are applied to at least part of the surface of an unsized or sized paper, in which the paper has or is provided with at least one cut-out for a window, and in which elevated pressure or elevated pressure and elevated temperature are allowed to act on the paper in such a way that at least some of the core/shell particles present in or on the paper are pressed into the cut-out so that the core/shell particles fill the cut-out, and in which the shell of the core/shell particles forms a matrix, at least in the cut-out and in an edge zone between cut-out and paper sheet. 
     
     
         35 . Process according to  claim 34 , in which the core/shell particles are applied to the cut-out in the paper. 
     
     
         36 . Process according to  claim 34 , in which a predominantly aqueous dispersion of core/shell particles is employed. 
     
     
         37 . Process according to  claim 29 , in which the security paper is additionally smoothed, pressed and/or embossed over the entire surface or part of the surface. 
     
     
         38 . Process according to  claim 29 , in which the security paper is firstly provided with various additional security features and subsequently smoothed, pressed and/or embossed over the entire surface or part of the surface. 
     
     
         39 . Process according to  claim 38 , in which the additional security features are introduced into the cellulose-containing paper pulp and/or applied to and/or introduced into the finished paper. 
     
     
         40 . Process according to  claim 38 , in which the additional security features are watermarks, planchettes, fibres, security threads, fluorescent dyes, infrared- or UV-active dyes, magnetic particles, electrically conductive particles, optically variable pigments, optically variable layers, optically variable prints, liquid-crystalline coatings, holograms, kinegrams, diffractive pigments, RFID elements, laser marks, chemical additives which become visible on illumination at certain wavelengths or on manipulation, microtexts, guillochés and the like. 
     
     
         41 . (canceled) 
     
     
         42 . Documents of value, such as banknotes, passports, identity documents, shares, bonds, certificates, cheques, credit notes, entry tickets, travel tickets, security labels and the like, comprising a security paper according to  claim 1 . 
     
     
         43 . Document of value according to  claim 42 , which has a transparent or semitransparent polymeric window and at least one second substrate, intimately connected thereto, which has at least one security feature, where the second substrate is connected to the security paper in such a way that the at least one security feature of the second substrate can be validated visually and/or by machine through the transparent or semitransparent window included in the security paper.