GB2307487A - Process for producing security paper - Google Patents
Process for producing security paper Download PDFInfo
- Publication number
- GB2307487A GB2307487A GB9523845A GB9523845A GB2307487A GB 2307487 A GB2307487 A GB 2307487A GB 9523845 A GB9523845 A GB 9523845A GB 9523845 A GB9523845 A GB 9523845A GB 2307487 A GB2307487 A GB 2307487A
- Authority
- GB
- United Kingdom
- Prior art keywords
- microspheres
- paper
- debonding agent
- fibres
- expanding
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
- D21H21/52—Additives of definite length or shape
- D21H21/54—Additives of definite length or shape being spherical, e.g. microcapsules, beads
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
- D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
Abstract
A process for producing security paper comprises forming a slurry of papermaking fibres and heat-expandable microspheres, wherein said fibres produce a strong paper such as banknote paper, forming the paper on a papermaking machine and drying the paper with drying cylinders at a temperature above 100{C to form strong paper at drying temperatures above the expansion temperature of the microspheres without expanding the microspheres, wherein the thus formed strong paper is treated with debonding agent to reduce the strength of the fibre-to-fibre bonds so that the microspheres are capable of expanding and then causing some or all of the microspheres to expand in the region where the debonding agent has been applied. The microspheres may be from 5 to 20 m in diameter and are capable of expanding at least 5 times, and preferably from 10 to 20 times, their initial volume.
Description
PROCESS FOR PRODUCING SECURITY PAPER
This invention relates to a process for producing security paper and in a particular embodiment to the production of security paper having a tactile security feature.
It is well known that the bulk of paper can be increased by incorporating into the furnish used to make the paper expandable microspheres. These microspheres are generally of 5 to 20 ssm in diameter and when heated above a critical temperature expand markedly, for example a diameter expansion of 4 to 5 times can be achieved at full expansion and this corresponds to a volume increase of the microspheres of more than 60 times. The critical temperature depends upon the specific type of microsphere. It is also well known that such microspheres can be expanded using as a heat source infra-red radiation, microwave radiation, conducted heat (e.g. contact with a drying cylinder) or lasers.
It is also well-known that paper may be produced having tactile effects by applying heat expandable microspheres locally and expanding the microspheres for example by using an all-over heating technique or by applying the microspheres over the entirety of the paper and activating them locally by using selective heating. Such selective heating may be achieved by one of the following methods: 1. The paper is over-printed with a heat absorbent material such as a black toner. The paper is then exposed to IR radiation which is preferentially absorbed by the heat absorbent material, thereby causing the microspheres to expand.
2. The paper may be masked by, for example, a copper etched mask, behind which is an IR source (lamp or laser). The microspheres expand in the exposed regions.
3. The paper may be brought into contact with a hot die that selectively heats areas of the paper surface.
4. The paper may be exposed to a modulated laser that selectively activates the microspheres.
U.S. Patent Specification No.5 125 996 discloses three-dimensional imaging paper having randomly distributed fibres and uniformly dispersed throughout unexpanded synthetic thermoplastic polymeric microspheres and a method wherein microspheres are expanded to provide portions of the paper where the microspheres are in the unexpanded form while in other portions the microspheres are in the expanded form.
Microspheres which are useful in papermaking are sold under the trademark EXPANCEL and sold by Nobel
Industries; they are described in Nobel Industries'
Technical Bulletin No.13 which is dated 10 February 1994 and entitled "EXPANCEL MICROSPHERES IN PAPER".
This Bulletin describes the expansion of the microspheres in the dryer section of the papermaking process. The EXPANCEL microspheres start to expand in the dryer section at a temperature of 70 to 75QC and the Bulletin states that this temperature must be reached in the paper and board web before the fibre-to-fibre bonds become too strong; if the bonds become too strong then the microspheres may be prevented from expanding. Accordingly, there is teaching that the use of the microspheres in the production of a strong substrate such as security paper which is used in the production of banknotes will not involve an expansion of the microspheres.
The previously described use of microspheres in papermaking has brought about an increase in the bulk of paper which has involved wood pulp based furnishes and often those containing a high proportion of waste paper. Such furnishes produce weak paper in comparison to banknote paper. In the drying stage the fibre matrix in the case of weak papers is not strong enough to constrain the microspheres when heated during the paper-drying stage and the microspheres accordingly expand at the critical temperature.
However, in the case of banknote paper and similar strong paper, the paper fibres in the drying stage have sufficiently strong fibre-to-fibre bonds to prevent the microspheres from expanding to any significant extent when the microspheres are heated in the drying stage to temperatures of or above the critical temperature when expansion normally occurs.
The process of paper manufacture includes generally the above-mentioned drying step in which drying cylinders are typically at a temperature of 80 to 140'C. The paper produced at this stage will be virtually dry having typically a moisture content of 8 to 15%, frequently 10%, before it reaches temperatures high enough to cause expansion of the microspheres which typically is from 80 to 150no. In weak papers, expansion of the microspheres having taken place during the drying process, it is not of course possible then to cause selective expansion of them and achieve tactile effects.In the case of strong papers, expansion of the microspheres in the drying stage does not occur and could only occur in general if the microspheres have an exceptionally low critical temperature and thus expand before the paper has become strong, i.e. before it has developed adequate fibre-to-fibre bonds.
The present invention is concerned with producing expansion of microspheres in strong paper and thus permits the selective expansion of microspheres to provide desirable selective raised portions which confer a tactile effect which has value as a security feature in security documents, especially banknotes.
Accordingly, the present invention provides
A process for producing security paper which comprises forming a slurry of papermaking fibres and heatexpandable microspheres, wherein said fibres produce a strong paper such as banknote paper, forming the paper on a papermaking machine and drying the paper with drying cylinders at a temperature above 100-C to form strong paper at drying temperatures above the expansion temperature of the microspheres without expanding the microspheres, wherein the thus formed strong paper is treated with debonding agent to reduce the strength of the fibre-to-fibre bonds so that the microspheres are capable of expanding and then causing some or all of the microspheres to expand in the region where the debonding agent has been applied.
When microspheres are expanded over the entirety of the paper the thickness and thus the stiffness of the paper are increased; this can be advantageous with a banknote as when printed with intaglio print better results are obtained because the paper is more compressible than corresponding paper without the expanded microspheres.
The microspheres are preferably from 5 to 20 tm in diameter and are capable of expanding at least 10 times their initial volume. The microspheres may be formed by encapsulating a low-boiling, vaporisable substance into a microcapsule of a thermoplastic resin. In accordance with the present invention, strong paper may be produced where substantially all the microspheres are expanded, but advantageously the microspheres are caused to expand by selectively heating them so that the expanded microspheres form a defined region or regions in the paper and create corresponding raised portions which provide a tactile effect.
The debonding agent preferably comprises at least 70% of water and optionally a thickener, such as polyvinyl alcohol which may be present in the debonding agent in an amount of 5 to 12 parts by weight. It is to be noted that the debonding agent should be substantially penetrated into the surface of the paper and should not have evaporated before the microspheres have expanded. The debonding agent may contain a variety of additives including the polyvinyl alcohol which acts as a rheology modifier or thickener; examples of other additives include surfactants, defoamers, biocides, evaporation inhibitors and the like.
Especially useful components of a debonding agent are low molecular alcohols such as methyl, ethyl, propyl or diethyl alcohol. Also, the presence of a surfactant is preferred. Penetration of these debonding agents may be increased by applying vacuum to the underside of the paper.
The debonding agent may be applied to the entirety of the surface of the strong paper when selective heating will create the raised portions in the desired locations. Alternatively, the debonding agent may be applied to predetermined regions where expansion is desired by a printing process such as a flexographic or screen printing process so that in the resulting security paper there are raised regions corresponding to the region to which the softening agent was applied and the raised region provides a tactile security feature.However, those skilled in the art will appreciate that other techniques can be used to provide printing in selected regions of the paper, e.g. by applying to the paper heating by means of infra-red radiation, microwave heating or other methods of causing the microspheres to expand then only those areas where the fibre-to-fibre bonds have been weakened by the debonding agent will expand.
Preferably, the microspheres are present in an amount of 3 to 15 dry parts by weight per 100 parts by weight of the papermaking fibres. The papermaking fibres preferably comprise at least 75% cotton fibres of mean fibre length of from 0.75 to 1.5 mm.
It is preferable that security paper in accordance with this invention is sized before the expansion of microspheres takes place and while normal paper sizes can be used, polyvinyl alcohol is preferred.
The present invention may be employed in the production of security paper by combining two or more preformed webs, especially 3 preformed webs, to form a 3-layer structure in which the microspheres are incorporated in one or more layers. The production of paper from preformed webs is well-known in the art.
The advantages which are obtainable by combining preformed webs include, where the microspheres are incorporated into a central web, it is possible to ensure that expanded microspheres will not interfere with the printing process when a security document is formed, and it will be appreciated that it will thus be possible to incorporate higher levels of microspheres into the central web than would be normal in producing security paper formed with a l-layer structure; such higher levels will cause interference with the printing process which can arise as a result of microspheres or portions thereof contaminating the printing plates. In another variant, the microspheres can be placed in one or both of the outer layers.
Where the microspheres are in just one outer layer then a tactile security feature can be obtained which is detectable on one side of the paper and lower levels of microspheres could be used in order to obtain a given tactile effect with commensurate cost benefits. Also, when the microspheres are placed in both outer layers of the 3-layer structure, different or differently positioned raised portions can be obtained to give different tactile effects on each side of the paper.
An additional embodiment of the invention concerns the paper forming process in which microspheres mixed with cotton fibre are applied to the paper in bands in much the same way as so-called silks and planchettes are currently applied. This has the benefit of reducing the quantity of microsphere required to achieve a tactile effect in a predetermined region of a banknote or other security document. Such bands may be as narrow as 10 mm. By applying the microspheres in this way, it is possible to ensure that the microspheres are only present in the top surface of the paper, thereby maximising their effect on one side in much the same way as applying the microspheres in a single layer of a 2- or 3-layer paper as described above.
In an further embodiment of the invention, the microspheres are expanded over and around a region containing a watermark. In this way, a tactile image in the region of the watermark is created and this serves to draw attention to the watermark itself. This is beneficial because it draws attention to a visual security feature that is difficult to counterfeit.
The invention will now be described further in the following example:
EXAMPLE
Paper was made in the laboratory by using the
following:
93 dry parts by weight cotton fibre of mean fibre
length 1.0 mm
7 dry parts by weight 820 DU EXPANCEL
microspheres supplied by Eka Nobel.
Following the production of the sheet after
drainage it was then dried over a laboratory
drying cylinder at 112'C and then sized in a
solution of polyvinyl alcohol to give a polymeric
content of 3.0 dry parts by weight per 100 parts
total weight. The paper was dried this time at 80'C. Examination of the paper by microscopy and
a thickness measurement showed that the
microspheres had not expanded to any measurable
extent.
A debonding agent consisting of 90 parts by
weight water and 10 parts per weight of polyvinyl
alcohol was then printed onto the resulting dried
paper in the form of indicia using a stencil.
The paper containing the debonding agent was then
transferred to a microwave oven where it was
heated for 30 seconds. The indicia was produced
during this stage so that in the final product
there was a raised region in the paper 20 to 100
microns thicker than the paper which was not
printed with the debonding agent and had a
thickness of 120-200 UM.
The accompanying Figure illustrates an effect which can be achieved by using the present invention.
Referring to the drawing, a sheet of security paper 10 has a raised portion 11 which provides a letter P and which constitutes a tactile security feature. The height of the letter P is 5 millimetres and the depth is 25 to 50 Um and the thickness of the paper itself is 100 m. The letter P was formed by applying a debonding agent through a mask or stencil after drying the paper and thereafter heating so that the microspheres in the predetermined region where the debonding agent was applied expanded and formed this valuable tactile feature.
It is surprising that expansion of microspheres can be achieved after the drying stage in the production of strong paper as described generally above and in the Example. By use of the invention a distinctly tactile feature can readily be incorporated into banknotes. This tactile feature has an unusually good durability because it is incorporated in the bulk of the paper. In contrast, ink-based tactile features such as are provided by intaglio printing are susceptible to wear because they are exposed on the surface of the substrate. A tactile feature produced in accordance with this invention cannot be reproduced in any satisfactory manner by using conventional copying and printing methods and therefore serves as a valuable anti-counterfeiting security measure. If desired, a tactile feature produced in accordance with the invention may be used as a feature to assist the blind or partially-sighted in the recognition of the denomination of banknotes and may have applications also outside the sphere of currency.
Claims (10)
1. A process for producing security paper which comprises forming a slurry of papermaking fibres and heat-expandable microspheres, wherein said fibres produce a strong paper such as banknote paper, forming the paper on a papermaking machine and drying the paper with drying cylinders at a temperature above 100'C to form strong paper at drying temperatures above the expansion temperature of the microspheres without expanding the microspheres, wherein the thus formed strong paper is treated with debonding agent to reduce the strength of the fibre-to-fibre bonds so that the microspheres are capable of expanding and then causing some or all of the microspheres to expand in the region where the debonding agent has been applied.
2. A process as claimed in claim 1 wherein the microspheres are from 5 to 20 m in diameter and are capable of expanding at least 5 times, and preferably from 10 to 20 times, their initial volume.
3. A process as claimed in claim 1 or claim 2, wherein the microspheres are each formed by encapsulating a low-boiling, vaporisable substance into a microcapsule of a thermoplastic resin.
4. A process as claimed in any one of the preceding claims, wherein the microspheres are caused to expand by selectively heating microspheres so that the expanded microspheres form a defined raised region or regions which provide a tactile security feature.
5. A process as claimed in claims 1 to 3, wherein the debonding agent is applied in predetermined regions so that in the resulting security paper there are raised regions corresponding to the region to which the debonding agent was applied and the raised region provides a tactile security feature.
6. A process as claimed in any one of the preceding claims, wherein the debonding agent comprises at least 70% of water and optionally a thickener.
7. A process as claimed in claim 6, wherein a thickener is used and is a polyvinyl alcohol present in an amount of 5 to 12 parts by weight of the debonding agent.
8. A process as claimed in any one of the preceding claims, wherein the microspheres are present in an amount of 3 to 15 dry parts by weight per 100 parts by weight of the papermaking fibres.
9. A process as claimed in any one of the preceding claims, wherein the papermaking fibres comprise at least 75% cotton fibres of mean fibre length of from 0.75 to 1.5 mm.
10. A process as claimed in any one of the preceding claims wherein the resulting security paper is printed to provide a security document, especially a banknote.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9523845A GB2307487B (en) | 1995-11-22 | 1995-11-22 | Process for producing security paper |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9523845A GB2307487B (en) | 1995-11-22 | 1995-11-22 | Process for producing security paper |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9523845D0 GB9523845D0 (en) | 1996-01-24 |
| GB2307487A true GB2307487A (en) | 1997-05-28 |
| GB2307487B GB2307487B (en) | 1999-03-17 |
Family
ID=10784252
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9523845A Expired - Fee Related GB2307487B (en) | 1995-11-22 | 1995-11-22 | Process for producing security paper |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2307487B (en) |
Cited By (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2001094698A1 (en) * | 2000-06-08 | 2001-12-13 | Metso Corporation | Security paper or board product and security package |
| WO2002084026A1 (en) * | 2001-04-11 | 2002-10-24 | International Paper Company | Cut resistant paper and paper articles and method for making same |
| EP1525102A1 (en) | 2002-07-18 | 2005-04-27 | Giesecke & Devrient GmbH | Security document |
| ES2249117A1 (en) * | 2004-02-05 | 2006-03-16 | Fabrica Nacional De Moneda Y Timbre - Real Casa De La Moneda. | Document paper with internal tactile recognition elements includes expansion agents activated by pressing and heating to form curved surface relief on the paper sheet |
| WO2008084372A1 (en) * | 2007-01-05 | 2008-07-17 | Lecce Pen Company Spa | Method for manufacturing reduced-weight paper, thin cardboard and cardboard, and compounds obtained therewith |
| US7482046B2 (en) | 2000-01-26 | 2009-01-27 | International Paper Company | Cut resistant paper and paper articles and method for making same |
| EP2028015A1 (en) | 2005-10-14 | 2009-02-25 | International Paper Company | Recording sheet with improved image dry time |
| FR2922561A1 (en) * | 2007-10-22 | 2009-04-24 | Arjowiggins Licensing Soc Par | SAFETY SHEET COMPRISING AN IRIDESCENT SAFETY BRAND |
| US7622022B2 (en) | 2006-06-01 | 2009-11-24 | Benny J Skaggs | Surface treatment of substrate or paper/paperboard products using optical brightening agent |
| US7666272B2 (en) | 2001-04-11 | 2010-02-23 | International Paper Company | Paper articles exhibiting water resistance and method for making same |
| US7892613B2 (en) | 2006-02-27 | 2011-02-22 | International Paper Company | Reducing top ply basis weight of white top linerboard in paper or paperboard |
| WO2011071668A1 (en) | 2009-12-08 | 2011-06-16 | International Paper Company | Method of production of fiber additive made from non - woody material and use |
| US7985320B2 (en) | 2005-04-06 | 2011-07-26 | Fabrica Nacional De Moneda Y Timbre-Real Casa De La Moneda | Security or special paper with internal tactile recognition elements |
| US8263186B2 (en) | 2001-04-11 | 2012-09-11 | International Paper Company | Paper articles exhibiting long term storageability and method for making same |
| WO2016094910A1 (en) * | 2014-12-12 | 2016-06-16 | Ctpg Operating, Llc | System and method for printing security documents on thermal paper |
| US10036124B2 (en) | 2012-01-23 | 2018-07-31 | International Paper Company | Separated treatment of paper substrate with multivalent metal salts and OBAs |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8652594B2 (en) | 2008-03-31 | 2014-02-18 | International Paper Company | Recording sheet with enhanced print quality at low additive levels |
| WO2010025383A1 (en) | 2008-08-28 | 2010-03-04 | International Paper Company | Expandable microspheres and methods of making and using the same |
| WO2010148156A1 (en) | 2009-06-16 | 2010-12-23 | International Paper Company | Anti-microbial paper substrates useful in wallboard tape applications |
| US8652593B2 (en) | 2009-12-17 | 2014-02-18 | International Paper Company | Printable substrates with improved brightness from OBAs in presence of multivalent metal salts |
| US8574690B2 (en) | 2009-12-17 | 2013-11-05 | International Paper Company | Printable substrates with improved dry time and acceptable print density by using monovalent salts |
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|---|---|---|---|---|
| GB1311556A (en) * | 1970-10-28 | 1973-03-28 | Dow Chemical Co | Process of forming a paper containing gasfilled spheres of thermoplastic resins |
| US4268615A (en) * | 1979-05-23 | 1981-05-19 | Matsumoto Yushi-Seiyaku Co., Ltd. | Method for producing relief |
| EP0031161A1 (en) * | 1979-12-20 | 1981-07-01 | GAO Gesellschaft für Automation und Organisation mbH | Antifalsification paper protected against faking and tampering |
| US5125996A (en) * | 1990-08-27 | 1992-06-30 | Eastman Kodak Company | Three dimensional imaging paper |
-
1995
- 1995-11-22 GB GB9523845A patent/GB2307487B/en not_active Expired - Fee Related
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1311556A (en) * | 1970-10-28 | 1973-03-28 | Dow Chemical Co | Process of forming a paper containing gasfilled spheres of thermoplastic resins |
| US4268615A (en) * | 1979-05-23 | 1981-05-19 | Matsumoto Yushi-Seiyaku Co., Ltd. | Method for producing relief |
| EP0031161A1 (en) * | 1979-12-20 | 1981-07-01 | GAO Gesellschaft für Automation und Organisation mbH | Antifalsification paper protected against faking and tampering |
| US5125996A (en) * | 1990-08-27 | 1992-06-30 | Eastman Kodak Company | Three dimensional imaging paper |
Cited By (28)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7482046B2 (en) | 2000-01-26 | 2009-01-27 | International Paper Company | Cut resistant paper and paper articles and method for making same |
| US7628887B2 (en) | 2000-06-08 | 2009-12-08 | Avantone Oy | Security paper or board product and security package |
| CN100395406C (en) * | 2000-06-08 | 2008-06-18 | 阿旺通公司 | Security paper or board product and security package |
| WO2001094698A1 (en) * | 2000-06-08 | 2001-12-13 | Metso Corporation | Security paper or board product and security package |
| WO2002084026A1 (en) * | 2001-04-11 | 2002-10-24 | International Paper Company | Cut resistant paper and paper articles and method for making same |
| US8263186B2 (en) | 2001-04-11 | 2012-09-11 | International Paper Company | Paper articles exhibiting long term storageability and method for making same |
| US7927458B2 (en) | 2001-04-11 | 2011-04-19 | International Paper Company | Paper articles exhibiting water resistance and method for making same |
| US7666273B2 (en) | 2001-04-11 | 2010-02-23 | International Paper Company | Paper articles exhibiting water resistance and method for making same |
| US7666272B2 (en) | 2001-04-11 | 2010-02-23 | International Paper Company | Paper articles exhibiting water resistance and method for making same |
| EP1525102A1 (en) | 2002-07-18 | 2005-04-27 | Giesecke & Devrient GmbH | Security document |
| ES2249117A1 (en) * | 2004-02-05 | 2006-03-16 | Fabrica Nacional De Moneda Y Timbre - Real Casa De La Moneda. | Document paper with internal tactile recognition elements includes expansion agents activated by pressing and heating to form curved surface relief on the paper sheet |
| KR101190679B1 (en) * | 2005-04-06 | 2012-10-12 | 파브리카 나씨오날 데 모네다 이 띰브레-레알 까사 데 라 모네다 | Special or security paper comprising internal touch recognition elements |
| US7985320B2 (en) | 2005-04-06 | 2011-07-26 | Fabrica Nacional De Moneda Y Timbre-Real Casa De La Moneda | Security or special paper with internal tactile recognition elements |
| EP2028015A1 (en) | 2005-10-14 | 2009-02-25 | International Paper Company | Recording sheet with improved image dry time |
| US8758886B2 (en) | 2005-10-14 | 2014-06-24 | International Paper Company | Recording sheet with improved image dry time |
| US7892613B2 (en) | 2006-02-27 | 2011-02-22 | International Paper Company | Reducing top ply basis weight of white top linerboard in paper or paperboard |
| US8382947B2 (en) | 2006-06-01 | 2013-02-26 | International Paper Company | Surface treatment of substrate or paper/paperboard products using optical brightening agent |
| US7622022B2 (en) | 2006-06-01 | 2009-11-24 | Benny J Skaggs | Surface treatment of substrate or paper/paperboard products using optical brightening agent |
| US7972477B2 (en) | 2006-06-01 | 2011-07-05 | International Paper Company | Surface treatment of substrate or paper/paperboard products using optical brightening agent |
| WO2008084372A1 (en) * | 2007-01-05 | 2008-07-17 | Lecce Pen Company Spa | Method for manufacturing reduced-weight paper, thin cardboard and cardboard, and compounds obtained therewith |
| FR2922561A1 (en) * | 2007-10-22 | 2009-04-24 | Arjowiggins Licensing Soc Par | SAFETY SHEET COMPRISING AN IRIDESCENT SAFETY BRAND |
| WO2009056730A2 (en) * | 2007-10-22 | 2009-05-07 | Arjowiggins Licensing | Security film comprising an iridescent security mark |
| WO2009056730A3 (en) * | 2007-10-22 | 2009-07-09 | Arjowiggins Licensing Sas | Security film comprising an iridescent security mark |
| US10259247B2 (en) | 2007-10-22 | 2019-04-16 | Arjowiggins Security | Security sheet including an iridescent security mark |
| EP2203313B1 (en) | 2007-10-22 | 2020-12-02 | Oberthur Fiduciaire SAS | Security film comprising an iridescent security mark |
| WO2011071668A1 (en) | 2009-12-08 | 2011-06-16 | International Paper Company | Method of production of fiber additive made from non - woody material and use |
| US10036124B2 (en) | 2012-01-23 | 2018-07-31 | International Paper Company | Separated treatment of paper substrate with multivalent metal salts and OBAs |
| WO2016094910A1 (en) * | 2014-12-12 | 2016-06-16 | Ctpg Operating, Llc | System and method for printing security documents on thermal paper |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2307487B (en) | 1999-03-17 |
| GB9523845D0 (en) | 1996-01-24 |
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