High security paper and process of manufacture

Abstract

The invention relates to high security paper wherein the security feature(s) is/are incorporated into the paper during the manufacturing process using a polymeric film as a carrier for the security feature(s). The invention enables the security feature(s) to be delivered at precise places into security paper used for such diverse applications as bank notes, passport paper, visa paper, security documents, etc. The polymeric film may be a cold water soluble film or hot water soluble film or water insoluble hydrophilic film or a or a non soluble non hydrophilic film or a combination of these films or slit strips of any of these woven or intertwined offline and incorporated into the paper during the paper making process. Alternatively the polymeric film may comprise zone coating or discreet printing or zone extrusion striping or formation of hot water soluble film on preformed cold water soluble film which is then inserted into paper during the paper making process. The combination of polymeric films may be plain or wholly or partially perforated. The security features may be light source readable or machine readable or both.

1 . A method of making a security paper having one or more security features at precise locations within the paper by using polymeric film as a carrier for the security feature(s) and incorporating the polymeric film containing the security feature(s) into the paper web during the paper making process. 
   
   
       2 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a cold water soluble film that dissolves and is absorbed into the pulp fibres of the web during the paper making process. 
   
   
       3 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a hot water soluble film that remains intact and adheres to the web during the paper making process. 
   
   
       4 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a non soluble hydrophilic film that remains intact and adheres to the web during the paper making process. 
   
   
       5 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a non soluble non hydrophilic film that remains intact in the web during the paper making process. 
   
   
       6 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a combination of cold and hot water soluble films wherein the cold water soluble film dissolves and is absorbed into the pulp fibres and the hot water soluble film remains intact and adheres to the web. 
   
   
       7 . A method according to  claim 6  wherein the security feature(s) is/are contained in the hot water soluble film. 
   
   
       8 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a combination of cold and non soluble hydrophilic films wherein the cold water soluble film dissolves and is absorbed into the pulp fibres and the non soluble hydrophilic film remains intact and adheres to the web. 
   
   
       9 . A method according to  claim 8  wherein the security feature(s) is/are contained in the non soluble hydrophilic film. 
   
   
       10 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a combination of cold and non soluble non hydrophilic films wherein the cold water soluble film dissolves and is absorbed into the pulp fibres and the non soluble non hydrophilic film remains intact in the web. 
   
   
       11 . A method according to  claim 10  wherein the security feature(s) is/are contained in the non soluble non hydrophilic film. 
   
   
       12 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is a cold water soluble film inserted/cast/coated with hot water soluble film strips or non soluble hydrophilic film strips or vice versa. 
   
   
       13 . A method according to  claim 1  wherein the security feature(s) is/are provided by a polymeric film which is in the form of a matrix wherein one or more polymeric films or PVA threads are inter-woven into a matrix by warp and weft method. 
   
   
       14 . A method according to  claim 12  or  13  wherein the width/size of the polymeric film strips range from 3 mm to 15 mm, preferably from 4 mm to 10 mm, more preferably from 5 mm to 7 mm. 
   
   
       15 . A method according to  claim 13  wherein the size of the PVA thread range from 50 deniers to 1000 deniers, preferably 150 deniers to 700 deniers, more preferably from 300 deniers to 500 deniers. 
   
   
       16 . A method according to  claim 1 , wherein the polymeric film embedded/embossed/printed with security feature(s) is applied to the wet paper pulp web during a cylinder mould process of paper making comprising the following steps:
 a. filling the vat with the pulp-water slurry entering;   b. formation of the paper body on the outside of the rotating cylinder covered with a wire cloth;   c. layering of a preformed polymeric film embedded/embossed/printed with security feature(s) onto the pulp fiber bed at the couch roll;   d. passing the construction through the vacuum boxes to remove excess water from the pulp bed;   e. passing the construction through press roll to remove excess water and then to dryers for further evaporating the moisture from the paper web.   
   
   
       17 . A method according to  claim 1 , wherein the polymeric film embedded/embossed/printed with security feature(s) is applied to the wet paper pulp web during a twin former process of paper making comprising the following steps:
 a. formation of first ply of wet paper web by the first former on a continuous moving belt;   b. incorporation of the polymeric film embedded/embossed/printed with security feature(s) into the first ply of the wet paper web with the help of a guide roll;   c. formation of the second ply of wet paper on the polymeric film side of the first ply of wet paper by the second former;   d. passing the construction through press section to remove excess water and then to dryers for further evaporating the moisture from the paper web.   
   
   
       18 . A method according to  claim 16  or  17  wherein the polymeric film includes at least one film containing the security feature(s) that remains intact between first and second paper webs during the paper making process. 
   
   
       19 . A method according to  claim 16  or  17  wherein the polymeric film includes at least one film that dissolves and is absorbed into the pulp fibres of the first and/or second paper webs. 
   
   
       20 . A method according to  claim 16  or  17  wherein the polymeric film comprises a combination of at least two films wherein at least one film is soluble at a lower temperature than the other film. 
   
   
       21 . A method according to  claim 16  or  17  wherein the water soluble film comprises at least one cold water soluble film and at least one hot water soluble film where the security feature(s) is/are provided by the hot water soluble film. 
   
   
       22 . A method according to  claims 1  to  21  wherein one or more polymeric films are perforated. 
   
   
       23 . Security paper made by the method according to any preceding claim. 
   
   
       24 . Security paper according to  claim 23  wherein the carrier polymeric film is incorporated into the fibres of the paper during the cylinder mould process of paper making. 
   
   
       25 . Security paper according to  claim 23  wherein the carrier polymeric film is incorporated between two webs of the paper during the twin former process of paper making. 
   
   
       26 . Security paper according to any of  claims 23  to  25  wherein the polymeric film is a water soluble film made from materials selected from the group comprising polyvinyl alcohol copolymer ionomers, polyvinyl alcohol homopolymer, non-ionomeric poly vinyl alcohol polymer, polymethacrylate, polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyurethane and edible film forming materials like polyethyleneglycol, polyvinylpyrrolidone, proteinaceous binders such as gelatin, modified gelatins such as phthaloyl gelatin, polysaccharides such as starch, gum Arabic, pullulan and dextrin and water+soluble cellulose derivatives or combination thereof. The cellulose derivatives used are methyl cellulose, hydroxy propyl cellulose, hydroxy propyl methyl cellulose, hydroxy propyl ethyl cellulose, hydroxy ethyl cellulose, carboxy methyl cellulose. 
   
   
       27 . Security paper according to any of the  claims 23  to  25  wherein the polymeric film is a non soluble non hydrophilic film selected from PP (Poly propylene), PE (Poly ethylene), LDPE (Low density poly ethylene), HDPE (high density polyethylene), LLDPE (Linear low density polyethylene), HIPS (High impact polystyrene), HMHDPE (High molecular high density polyethylene), BOPP (Biaxially oriented poly propylene). 
   
   
       28 . Security paper according to any of the  claims 23  to  25  wherein the polymeric film is a non soluble non hydrophilic film made from biodegradable materials such as PLA (Poly Lactic Acid), PHA (polyhydroxyalkanoic acid), thermoplastic starch materials or biodegradable polyesters such as ecoflex. 
   
   
       29 . Security paper according to any of  claims 23  to  29  wherein the polymeric film has a thickness ranging from 5 microns to 150 microns, preferably from 10 microns 70 microns, more preferably from 15 microns to 35 microns. 
   
   
       30 . Security paper according  claim 25  wherein the paper comprises at least two plies. 
   
   
       31 . Security paper according to  claim 25  having a polymeric film containing the security feature(s) between the plies. 
   
   
       32 . Security paper according to any of  claims 23  to  31  wherein the security feature(s) are selected from the group comprising micro-printed text, logos, metallised/demetallised particles/fibres, bar-codes, watermarks, nano-particles, micro-taggants, DNA (synthetic, natural), UV, PCR, computer, machine readable, RFID devices.