Process for manufacturing a material in sheet form, comprising at least one fibrous layer and security and/or decorative elements

Abstract

A process for manufacturing a material in sheet form, comprising at least one fibrous layer and a plurality of security and/or decorative elements, the process comprising at least one of the following steps: the security and/or decorative elements are sprayed onto one face of the fibrous layer, which is running along a predetermined direction, especially when the fibrous layer is still wet, so as to form at least one continuous pattern having at least one edge, approximately along the run direction, not entirely parallel to the run direction, and a pattern comprising a succession of separate zones, and security and/or decorative elements of at least two different types and/or having a variable concentration are sprayed onto one face of the fibrous layer, especially when it is still wet.

1 . A process for manufacturing a sheet material comprising at least one fibrous layer and a plurality of security and/or decorative elements, the process comprising at least one of:
 spraying the security and/or decorative elements onto one face of the fibrous layer, while traveling along a predetermined direction, so as to form one at least of a continuous pattern having at least one edge, substantially in the direction of travel, not completely parallel to the direction of travel and a pattern comprising a succession of disjointed zones; and   spraying onto one face of the fibrous layer, security and/or decorative elements of at least two different types and/or that have a variable concentration.   
     
     
         2 . The process as claimed in  claim 1 , the security and/or decorative elements being sprayed onto the fibrous layer using a pressurized fluid, especially a pressurized gas. 
     
     
         3 . The process as claimed in  claim 1 , comprising:
 dispersing security elements in a fluid; and   spraying the security and/or decorative elements onto the fibrous layer.   
     
     
         4 . The process as claimed in  claim 1 , the spraying of the security and/or decorative elements being carried out using a spraying system comprising one or more spray nozzles. 
     
     
         5 . The process as claimed in  claim 1 , the spraying system comprising a device for atomizing a liquid medium in order to create fine droplets. 
     
     
         6 . The process as claimed in  claim 4 , the spraying system comprising at least one nozzle that may be alternately fed by at least two reservoirs of security and/or decorative elements capable of alternately spraying the security and/or decorative elements originating from the two reservoirs. 
     
     
         7 . The process as claimed in  claim 4 , the spraying system comprising at least one jet divider arranged in order to divide, at the outlet of a nozzle, one jet into several jets. 
     
     
         8 . The process as claimed in  claim 1 , the security and/or decorative elements being sprayed while forming at least one jet, the process comprising:
 moving the fibrous layer along a predetermined direction;   moving the jet along a direction that is not parallel to the direction of movement of the fibrous layer.   
     
     
         9 . The process as claimed in  claim 1 , the security and/or decorative elements being sprayed onto the fibrous layer continuously. 
     
     
         10 . The process as claimed in  claim 1 , the security and/or decorative elements being sprayed onto the fibrous layer intermittently. 
     
     
         11 . The process as claimed in  claim 4 , the security and/or decorative elements being sprayed onto the fibrous layer intermittently, and the spraying system being combined with a control system arranged in order to control the spraying of the security and/or decorative elements. 
     
     
         12 . The process as claimed in  claim 11 , the control system comprising at least one of a pneumatic device and of a peristaltic device, or a combined pneumatic/peristaltic device arranged in order to control the spraying frequency, or a centrifugal pump or a mono pump. 
     
     
         13 . The process as claimed in  claim 1 , the security elements being sprayed by forming at least one jet that has, in transverse cross section, a shape chosen from: a straight line segment, a corner such as a right-angled corner, a triangle, a rectangle or a square, a non-rectilinear curve such as an arc of a circle, a circle, an ellipse, an oval or S-shaped portion, a disk, or a wavy shape. 
     
     
         14 . The process as claimed in  claim 1 , the spraying of the security and/or decorative elements onto the fibrous layer being carried out in-line, downstream of the wet part of the papermaking machine that is used to form the fibrous layer, especially before passing into a drying assembly of the papermaking machine. 
     
     
         15 . The process as claimed in  claim 1 , the security and/or decorative elements being sprayed onto the fibrous layer so as to be dispersed over only one portion of the corresponding face of the fibrous layer. 
     
     
         16 . The process as claimed in  claim 1 , comprising:
 spraying, simultaneously or successively, especially alternately, security and/or decorative elements of at least two different types onto the fibrous layer.   
     
     
         17 . The process as claimed in  claim 1 , the security and/or decorative elements comprising elements detectable to the naked eye, in reflection and/or in transmission, in daylight. 
     
     
         18 . The process as claimed in  claim 1 , the security and/or decorative elements comprising elements detectable to the naked eye, in reflection and/or in transmission under ultraviolet lighting. 
     
     
         19 . The process as claimed in  claim 1 , the security and/or decorative elements comprising elements arranged in order to emit a specific signal when they are subjected to an optoelectronic, electromagnetic, electric, magnetic, thermal or acoustic excitation. 
     
     
         20 . The process as claimed in  claim 1 , the security elements comprising at least one of the following elements:
 an active material, such as for example a chemical substance that absorbs in the UV or elements detectable by X-ray fluorescence;   a particle or a pigment, especially one that is luminescent, fluorescent and/or phosphorescent;   a biological, chemical or physical marker;   a fiber such as a magnetic fiber, especially one that is weakly magnetized, or a fiber that is optically excitable, especially by exposure to infrared radiation; and   a planchette.   
     
     
         21 . The process as claimed in  claim 1 , the decorative elements comprising metallic particles and/or shiny or matt or colored particles, made of mineral or plastic material(s). 
     
     
         22 . The process as claimed in  claim 1 , the sheet material comprising at least one authentication and/or identification structure, the security elements covering a zone of the fibrous layer that is superposed at least partially on the authentication and/or identification structure. 
     
     
         23 . The process as claimed in  claim 22 , the authentication structure being chosen from at least one of the following elements: a watermark, an optically variable element such as a hologram, a strip element, a foil, a patch, a security thread, or printing. 
     
     
         24 . A papermaking machine that makes it possible to carry out the process as claimed in  claim 1 , the machine comprising:
 at least one wet part for forming a fibrous layer continuously; and   a spraying system arranged in order to spray security and/or decorative elements over a still wet fibrous layer, formed in the wet part of the machine.   
     
     
         25 . The machine as claimed in  claim 24 , the spraying system comprising at least one spraying device arranged in order to spray the security and/or decorative elements. 
     
     
         26 . A sheet material obtained by the implementation of the process as claimed in  claim 1 . 
     
     
         27 . The material as claimed in  claim 26 , the security and/or decorative elements covering one portion only of one face of the fibrous layer, the security elements being dispersed at least partially in the bulk of the fibrous layer, over a thickness smaller than that of the fibrous layer. 
     
     
         28 . The material a s claimed in  claim 26 , the security and/or decorative elements that form a pattern having a succession of disjointed zones that are identical and/or repeated regularly. 
     
     
         29 . The material as claimed in  claim 25 , comprising at least two types of security and/or decorative elements, the security elements of one given type covering one portion only of the face of the fibrous layer. 
     
     
         30 . The material as claimed in  claim 29 , comprising at least two zones formed respectively by security and/or decorative elements of different types, these zones being adjacent or at least partially superposed. 
     
     
         31 . The material as claimed in  claim 26 , comprising security and/or decorative elements that form one at least of:
 a continuous pattern, that extends from a first edge of the sheet material to a second opposite edge; and   a succession of disjointed zones.   
     
     
         32 . The material as claimed in  claim 31 , the continuous zone forming a pattern in the shape of a wavy strip or zigzag. 
     
     
         33 . A process as claimed in  claim 1 , wherein the spraying is carried out while the fibrous layer is still wet.