GB2306178A - Method for making security-type paper with localized low opacity areas and paper so obtained - Google Patents
Method for making security-type paper with localized low opacity areas and paper so obtained Download PDFInfo
- Publication number
- GB2306178A GB2306178A GB9703697A GB9703697A GB2306178A GB 2306178 A GB2306178 A GB 2306178A GB 9703697 A GB9703697 A GB 9703697A GB 9703697 A GB9703697 A GB 9703697A GB 2306178 A GB2306178 A GB 2306178A
- Authority
- GB
- United Kingdom
- Prior art keywords
- paper
- sheet
- opacity
- screen
- thickness
- 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
- 238000000034 method Methods 0.000 title claims abstract description 26
- 239000006185 dispersion Substances 0.000 claims abstract description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 7
- 229920003043 Cellulose fiber Polymers 0.000 claims description 5
- 238000004049 embossing Methods 0.000 claims description 4
- 238000001035 drying Methods 0.000 claims description 3
- 239000000835 fiber Substances 0.000 abstract 1
- 230000006835 compression Effects 0.000 description 10
- 238000007906 compression Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000007900 aqueous suspension Substances 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 235000012571 Ficus glomerata Nutrition 0.000 description 1
- 240000000365 Ficus racemosa Species 0.000 description 1
- 235000015125 Sterculia urens Nutrition 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000004519 grease Substances 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000002480 mineral oil Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 235000015112 vegetable and seed oil Nutrition 0.000 description 1
- 239000008158 vegetable oil Substances 0.000 description 1
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F11/00—Processes for making continuous lengths of paper, or of cardboard, or of wet web for fibre board production, on paper-making machines
- D21F11/006—Making patterned paper
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21F—PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- D21F1/00—Wet end of machines for making continuous webs of paper
- D21F1/44—Watermarking devices
Landscapes
- Paper (AREA)
Abstract
Method for making a paper sheet. According to the invention, the sheet comprises at least one region with an area of at least 0.4 cm 2 which is less opaque than the rest of the sheet. An aqueous dispersion containing at least cellulosic fibers is disposed on an embossed screen (3), optionally placed on a cylinder mould, the excess moisture is drained from the sheet, and the sheet formed is then recovered on a lifting wire and dried. The watermarked wire is crimped to reduce the thickness of the embossed part. Application to paper for banknotes.
Description
METHOD FOR MAKING SECURITY-TYPE PAPER COMPRISING LOCALIZED ZONES
OF LOW OPACITY AND PAPER OBTAINED IN THIS WAY.
The invention concerns a method for making a paper comprising localized zones of low opacity as compared with the opacity of the remaining paper.
In the present invention "paper" signifies any sheet obtained in a wet process by means of a suspension of natural cellulose fibres and/or synthetic fibres which may contain various fillers and various additives currently used in the paper industry.
In the prior art, papers are already known which are rendered transparent. These papers are, for example, rendered transparent by chemical compositions (see in particular the French
Patent No.82 05124 filed on the 15th March 1982 by ARJOMARI
PRIOUX). These papers are rendered transparent over their whole surface and are intended for applications in industrial drawing, reproduction of plans etc.
Chemical processes for obtaining a partial transparence, that is to say, at specified points, are also known. These methods use compositions based on grease or mineral or vegetable oils which are deposited by way of imprinting. However, it is difficult to print on these zones rendered transparent by means of the usual current printing techniques (offset, intaglio, process engraving etc.).
Moreover, it is known that differences in thickness and density are obtained in paper, in particular, by the technique of watermarks used for making paper secure for banknotes, identity documents, or official documents and securities. These watermarks are obtained during the manufacture of the paper sheet by cylinder moulds having impressed portions that are either sunk or in relief, or by means of dandy rolls having designs that are sunk or in relief associated with a flat table (the Foudrinier machine). An image is then obtained which, when the paper sheet is viewed in transmission, appears either clear if the dandy roll has a design in relief, or dark if the dandy roll has a sunk design.The clear zones are due to the fact that the thickness of the sheet and the density of the fibres are lower in clear watermarks than the thickness of the sheet and the density of the fibres in the zones where there are no imprints by the dandy roll. On the contrary, the dark zones are due to the fact that the thickness of the sheet and the density of the fibres are greater.
Such watermarks have clear portions which generally have a surface area of a few mm2 and the variation in opacity between the clear portion of the watermark and the non-watermarked paper is small. If it is intended to obtain a print on the clear zones of these watermarks, it is difficult to cause the clear zones and the print to correspond, and even with very precise registering of the watermarks, it is difficult to obtain a good coordination.
In the European Patent No. 388 090 filed on the 9th March, 1990 by the DE LA RUE COMPANY PLC, a security-type paper has been described which has zones with a reduced opacity at specified and well localized points, the zones making it possible to see with the naked eye by way of transmission, prints carried on the opposite side to the side along which the paper is viewed. The zones may be obtained, for example, in the form of uatermarks by using methods with cylinder moulds or with dandy rolls.
In the European Patent No. EP-A-549 384 filed by the Applicant and published on the 30th June 1993, a method has been described for making a sheet of paper, comprising at least one zone having a reduced thickness as compared with the thickness of the rest of the sheet and having a surface area of at least 0.4 cm2, by disposing on a screen embossed or not embossed, disposed if required on a cylinder mould, an aqueous dispersion containing at least cellulose fibres, by draining the water so as to form the sheet, in the presence of a dandy roll or not, by recovering the sheet formed on a lifting screen and by drying.Flexible parts are used which are associated with the waternarking screen, the dandy roll or with the cylinder mould, so that the draining of the water during the formation of the sheet in the zone of the flexible part is reduced as compared with the draining of the water in the zone not having any flexible part.
The paper sheet obtained according to this process is such that the zone having a reduced thickness has a lower thickness up to 40X of the thickness of the rest of the sheet. The sheet may also be such that the said zone has an average lower opacity up to 40X of the opacity of the rest of the sheet.
In the Application No.93 02373 for a French Patent filed by the
Applicant on the 2nd March 1993, another method has been described for making a paper sheet comprising at least one region having a reduced thickness as compared with the thickness of the rest of the sheet, characterized in that - a first paper layer is formed on a screen of a first wet
portion of a paper-making machine, - a second paper layer is formed on a screen of a second wet
portion of a paper-making machine, - one of the two paper layers having at least local regions of
a smaller thickness, so that the thickness of the two paper
layers in the said regions is up to 80 X as compared with
the thickness of the rest of the sheet, - the two layers are combined and are dried.
One or even two paper layers can be readily obtained so as to be very thin in places, at least one of the paper layers in one zone being locally reduced so that the thickness of the set of the two layers is sufficiently reduced in order to obtain a good transparence.
The methods described in the above mentioned documents certainly make it possible to obtain transparent zones, but one problem which arises is that the transparence of these zones is not re gular, that is to say, the look-through of the zones is not homogeneous.
Indeed, when flexible parts are used which are attached to the watermark screen or to the dandy roll or to the cylinder mould, uniform dewatering is not obtained.
Thus the object of the invention is to provide a method for making a paper having localized zones of low opacity, these zones having a homogeneous look-through and opacity.
For this purpose, the invention concerns a method for making a paper sheet having at least one zone of reduced opacity, as compared with the opacity of the rest of the sheet and having a surface area of at least 0.4 cm2, by disposing on an embossed screen disposed, if required, on a cylinder mould, an aqueous dispersion containing at least cellulose fibres, by draining the water so as to form the sheet, in the presence of a dandy roll or not, by recovering the formed sheet on a lifting screen and by drying it, the method being such that the watermarking screen is compressed, that is to say, that the thickness of the screen is reduced in the embossed portion so as to reduce the space between the meshes of the screen, and that one thus reduces the size of the meshes.
In accordance with a preferred mode of embodiment of the invention, the thickness of the embossed part is reduced, preferably by half.
More preferentially, the final thickness of the embossed part is comprised between 0.3 and 0.16 mm for an initial thickness of 0.46 mm.
According to one mode of embodiment, the height H of the embossed portion is comprised between 0.3 and 1.5 mm, preferably 0.8 mm, and the embossing angle is comprised between 2 and 6 .
In accordance with the method of the invention, a paper is obtained whose opacity variation is comprised between 2 and 6, preferably 4, this variation being measured according to a method of correlation between the density of the fibres of the paper and the opacity of the paper.
According to the method of the invention a paper is obtained having at least one zone with a reduced opacity, the trace of the compressed zone appearing on one side of the zone with a reduced opacity, while the trace of the lifting screen appears on the other side of the zone.
The description that follows with reference to the drawings and attached examples will make it possible to understand how the invention can be put into practice.
Figure 1 is a view of a cylinder mould machine intended for the manufacture of paper in accordance with the invention.
Figure 2 is a sectional view on an enlarged scale of the watermarking screen at the level of the embossed portion.
Figure 3 is an enlarged top view of the watermarking screen.
In Figure 1, a cylinder mould machine has been represented which is used for manufacturing security-type paper, and more particularly, paper for banknotes. In the known way, an aqueous suspension 1 of cellulose fibres is obtained, wherein a cylinder mould 2 is caused to rotate, that is to say, a cylinder formed by several superposed grilles, one of which being a watermarking grille or screen 3 which is embossed, that is to say, which comprises embossed portions such as shown at 6 in Figure 2. The aqueous suspension 1 is deposited on the cylinder mould 2 so as to form a sheet 4 which is lifted by means of a lifting screen schematically represented at 5. Because of the embossed portions, fewer fibres are deposited thereon and the paper then has clear watermarks.
In Figure 2 a portion of an embossed screen has been represented in cross-section. The screen 3 has an embossing height H and an initial thickness e,. Because the screen is compressed at the level of the embossed portion, the final thickness e2 of the screen is less than its initial thickness e,.
For effecting the compression, a tool is used which has a head whose profile corresponds to the shape of the desired embossed portion, and this head is applied to the screen by tightening the screen on the one hand, and by applying the compressing head on the other hand, while exerting pressure. Because of this, the size of the initial meshes M1 is reduced and the meshes M2 after compression are more closely packed. Thus it may be said that the space inside one mesh M2 (or empty mesh space) is smaller than the space of a mesh M,. The draining of the water in the compressed portion is reduced as compared with the draining of the water in the portion that has not been compressed, and a clear watermark is formed. Because of the compression, regularity is obtained in the meshes M2 , and this in a surprising manner.Thus the dewatering through the compressed portion will be regular and the look-through of the clear watermark will regular.
Thus if the initial thickness e, is 0.46 mm, the thickness e2 of the embossed portion is comprised between 0.3 and 0.16 mm.
According to one mode of embodiment of the invention, the height
H of the embossed portion is comprised between 0.3 and 1.5 mm, preferably 0.8 mm. The embossing angle a which is formed by the side 7 of the embossed portion and the axis xx perpendicular to the screen is preferably comprised between 2 and 6".
Example 1: Paper is manufactured by means of a cylinder mould, this paper having a dry grammage of 70 to 87 g/I? . An 0.8 mm high embossed portion is obtained, and this embossed portion has a circular profile 2 cm in diameter. Various compressions of the thickness e2 are effected on a screen having a thickness e1 of 0.46 mm and the opacity variation is measured between the zones with a reduced opacity and the rest of the sheet.
The following results are obtained
Compression 0.3 0.16 0.2 e2 (mm) Opacity variation 0.1 8 4 The compression to 0.3 mm does not yield a sufficiently reduced opacity; the compression to 0.16 mm entails the formation of a hole in the paper sheet. Only the compression to 0.2 mm yields an opacity variation of 4, which is considered as correct.
The reduced opacity zone has a regular look-through. Moreover, the trace of the compressed zone will be seen on one side of this zone and the trace of the lifting screen will be seen on the opposite side of the zone. Since the embossed grille and the lifting screen have different mesh sizes, these will be easily recognized by the expert.
Example 2
A paper is manufactured having a grammage of 87 to 98 g/m2.
Various compressions are effected. The following results are obtained:
Compression 0.3 0.16 0.19 e2 (mm) Opacity variation 0 7.5 4 l The opacity variations are measured as follows an opacimeter EEL of The Diffusion Systems Company Ltd. (United
Kingdom) is used. This opacimeter has a reading head which illuminates the paper. The opacity of the sheet is noted. Now this reading head has a larger diameter than the reduced opacity zone of the sheet in accordance with the invention. The opacity of this zone therefore cannot be measured directly. One therefore proceeds by way of correlation, by measuring the density of various sheets not having any reduced zones and by measuring their opacity.
The following table is obtained:
Density 0.3 0.4 o.s 0.5 0.60.70.80.9 1.0 Opacity 40.0 63.2 72.1 78.5 83.8 88.1 91.2 93.3 When it is intended to measure the opacity of a zone with an opacity reduced in accordance with the invention, its density is measured and its opacity is obtained by correlation. In this way, one calculates the difference in opacity between the zone with a reduced opacity and the rest of the sheet.
Of course, the zones with an opacity reduced in accordance with the invention, may have any desired shape : round, oval etc. and may have different sizes.
Claims (8)
1. A method for making a paper sheet comprising at least one zone of reduced opacity as compared with the opacity of the rest of the sheet and having a surface area of at least 0.4 cm', by disposing on an embossed screen (3), placed if required on a cylinder mould, an aqueous dispersion containing at least cellulose fibres by draining the water so as to form the sheet, by recovering the formed sheet on a lifting screen and by drying, the method being characterized in that the watermarking screen is compressed, that is to say, that the thickness of the screen is reduced in the embossed portion.
2. A method according to claim 1, characterized in that the thickness e1 of the embossed portion (6) is reduced, preferably by half.
3. A method according to claim 1, characterized in that the final thickness e2 of the embossed portion (6) is comprised between 0.3 and 0.16 mm for an initial thickness e, of 0.46 mm.
4. A method according to one of the preceding claims, characterized in that the height H of the embossed portion (6) is comprised between 0.3 and 1.5 mm, preferably 0.8 mm.
5. A method according to one of claims 1 to 4, characterized in that the embossing angle a is comprised between 2 and 6".
6. A paper according to claim 5, characterized in that the opacity variation between the sheet and the zone of reduced opacity is comprised between 2 and 6, preferably 4.
7. A paper according to claim 6, characterized in that it has the trace of the compressed zone appearing on one side of the zone of reduced opacity, while the trace of the lifting screen appears on the other side of the zone.
8. Application of a paper according to one of claims 6 and 7 to security papers, papers for banknotes.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9410242A FR2723971B1 (en) | 1994-08-24 | 1994-08-24 | PROCESS FOR THE MANUFACTURE OF SECURITY PAPER COMPRISING LOCALIZED AREAS OF LOW OPACITY AND PAPER THUS OBTAINED |
| PCT/FR1995/001097 WO1996006220A1 (en) | 1994-08-24 | 1995-08-17 | Method for making security-type paper with localized low opacity areas and paper so obtained |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9703697D0 GB9703697D0 (en) | 1997-04-09 |
| GB2306178A true GB2306178A (en) | 1997-04-30 |
| GB2306178B GB2306178B (en) | 1998-04-29 |
Family
ID=9466462
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9703697A Expired - Fee Related GB2306178B (en) | 1994-08-24 | 1995-08-17 | Method for making security-type paper comprising localized zones of low opacity and paper obtained in this way |
Country Status (7)
| Country | Link |
|---|---|
| BE (1) | BE1008682A3 (en) |
| DE (1) | DE19581738T1 (en) |
| FR (1) | FR2723971B1 (en) |
| GB (1) | GB2306178B (en) |
| IT (1) | IT1280922B1 (en) |
| NL (1) | NL1001049C2 (en) |
| WO (1) | WO1996006220A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100360740C (en) * | 2005-12-23 | 2008-01-09 | 中国印钞造币总公司 | Process for making high quantitative watermark anti-forge paper |
| US7632380B2 (en) * | 2002-05-22 | 2009-12-15 | Arjowiggins Security | Article formed from at least a fibrous material jet comprising at least a null thickness zone and method for making same |
| US8397995B2 (en) | 2007-12-24 | 2013-03-19 | Arjowiggins Security | Security structure including nematic liquid crystals |
| US8449719B2 (en) | 2007-12-28 | 2013-05-28 | Arjowiggins Security | Security paper |
| EP2947202A1 (en) * | 2014-05-21 | 2015-11-25 | Landqart AG | Safety paper with watermark |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2804448B1 (en) | 2000-02-01 | 2002-04-05 | Arjo Wiggins Sa | SECURITY PAPER COMPRISING A SECURITY ZONE, METHOD FOR PRODUCING SUCH PAPER AND DEVICE FOR CARRYING OUT SAID METHOD |
| FR2804447B1 (en) | 2000-02-01 | 2002-04-05 | Arjo Wiggins Sa | PAPER COMPRISING A MULTI-TONING FILIGRANE AND CANVAS FOR MANUFACTURING THIS PAPER |
| CN100376748C (en) * | 2004-12-29 | 2008-03-26 | 孙显林 | A kind of anti-counterfeiting material |
| CN104611976A (en) * | 2015-01-04 | 2015-05-13 | 昆山钞票纸业有限公司 | Cylinder mould with watermark supporting structure and anti-counterfeiting paper manufactured through same |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE623516C (en) * | 1900-01-01 | |||
| DE238640C (en) * | 1900-01-01 | |||
| US1616222A (en) * | 1922-05-18 | 1927-02-01 | American Writing Paper Company | Fourdrinier-wire screen |
| CH244613A (en) * | 1945-05-25 | 1946-09-30 | Reinhardt Erwin | Device on paper machines for the production of watermarks that appear darker when viewed through the paper compared to the same. |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2684698B1 (en) * | 1991-12-09 | 1994-01-21 | Arjo Wiggins Sa | PROCESS FOR THE MANUFACTURE OF A PRODUCT COMPRISING LOCALIZED AREAS OF REDUCED OPACITY AND THE PAPER THUS OBTAINED. |
-
1994
- 1994-08-24 FR FR9410242A patent/FR2723971B1/en not_active Expired - Fee Related
-
1995
- 1995-08-17 WO PCT/FR1995/001097 patent/WO1996006220A1/en not_active Application Discontinuation
- 1995-08-17 GB GB9703697A patent/GB2306178B/en not_active Expired - Fee Related
- 1995-08-17 DE DE19581738T patent/DE19581738T1/en not_active Withdrawn
- 1995-08-23 IT IT95TO000699A patent/IT1280922B1/en active IP Right Grant
- 1995-08-24 NL NL1001049A patent/NL1001049C2/en not_active IP Right Cessation
- 1995-08-24 BE BE9500710A patent/BE1008682A3/en not_active IP Right Cessation
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE623516C (en) * | 1900-01-01 | |||
| DE238640C (en) * | 1900-01-01 | |||
| US1616222A (en) * | 1922-05-18 | 1927-02-01 | American Writing Paper Company | Fourdrinier-wire screen |
| CH244613A (en) * | 1945-05-25 | 1946-09-30 | Reinhardt Erwin | Device on paper machines for the production of watermarks that appear darker when viewed through the paper compared to the same. |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7632380B2 (en) * | 2002-05-22 | 2009-12-15 | Arjowiggins Security | Article formed from at least a fibrous material jet comprising at least a null thickness zone and method for making same |
| CN100360740C (en) * | 2005-12-23 | 2008-01-09 | 中国印钞造币总公司 | Process for making high quantitative watermark anti-forge paper |
| US8397995B2 (en) | 2007-12-24 | 2013-03-19 | Arjowiggins Security | Security structure including nematic liquid crystals |
| US8449719B2 (en) | 2007-12-28 | 2013-05-28 | Arjowiggins Security | Security paper |
| EP2947202A1 (en) * | 2014-05-21 | 2015-11-25 | Landqart AG | Safety paper with watermark |
| CH709680A1 (en) * | 2014-05-21 | 2015-11-30 | Landqart Ag | Dewatering screen for manufacturing paper with at least one watermark and therefore made paper with a watermark. |
Also Published As
| Publication number | Publication date |
|---|---|
| NL1001049C2 (en) | 1996-04-22 |
| NL1001049A1 (en) | 1996-02-26 |
| FR2723971A1 (en) | 1996-03-01 |
| WO1996006220A1 (en) | 1996-02-29 |
| GB2306178B (en) | 1998-04-29 |
| GB9703697D0 (en) | 1997-04-09 |
| DE19581738T1 (en) | 1997-07-24 |
| ITTO950699A1 (en) | 1997-02-23 |
| ITTO950699A0 (en) | 1995-08-23 |
| FR2723971B1 (en) | 1996-10-04 |
| IT1280922B1 (en) | 1998-02-11 |
| BE1008682A3 (en) | 1996-07-02 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20020817 |