CN1106091A

CN1106091A - Improvement of tamper indicating charaterastics of paper

Info

Publication number: CN1106091A
Application number: CN94116458A
Authority: CN
Inventors: P·豪兰德
Original assignee: Portals Ltd
Current assignee: Portals Ltd
Priority date: 1993-09-30
Filing date: 1994-09-26
Publication date: 1995-08-02
Also published as: WO1995009276A1; GB2283026A; GB2283026B; ZA946600B; AU7622394A; GB9320206D0

Abstract

The invention relates to improvements in security features in paper and in particular to a method of making paper and transparentising selected areas of paper to provide enhanced security features. The invention thus provides a method of making paper comprising the steps of depositing fibres onto a support surface to form a porous absorbent sheet , applying a composition comprising a transparentising resin containing an iridescent substance to at least a portion of said porous sheet and subsequently impregnating the porous sheet with a sizing resin.

Description

Improvement of tamper indicating charaterastics of paper

The present invention relates to the improvement of security features for paper, particularly make the method for paper and make the selection area transparence of paper so that the anti-counterfeiting characteristic that increases to be provided.

Marketable securities and distinguishing mark, as banknote, passport, identity card etc. be easy to be duplicated or forge, color copy machine and other imaging systems more and more common, and the improvement of color dub technical quality has caused the increase of file forgery amount.Therefore need to improve the anti-counterfeiting characteristic of this class file or paper, add additional anti-counterfeiting characteristic or imitating discovering and stoping of existing feature.Used and introduce the step that light becomes feature in this class file, this light becomes feature and can not duplicate with duplicating.Therefore just require to introduce that naked eyes can be distinguished but be " invisible " or seem different features with duplicator.Because copy method generally comprises and reflects high-octane light the original document that contains image can be copied, a solution is that one or more features are attached on the file, and these features have different perceived effects in reflection or transmitted light.The example of this anti-counterfeiting characteristic comprises watermark, the anti-counterfeiting line of imbedding, luminous pigment etc.

EP-A2-0203499 discloses the method that adopts false watermark on paper.The method comprises the preparation of the paper that contains heat-sensitive materials, and the existence of heat-sensitive materials makes paper according to the change of temperature the variation of translucence be arranged, and when heat being imposed on the part surface of paper subsequently, a part of zone of paper just becomes translucent.

US-A-2021141 discloses and a kind of paper has been adopted the method for false watermark, and it is to become on the paper to adopt resin combination, making it to infiltrate in the paper, making paper become more transparent or semitransparent than its surrounding area.

GB-A-1489084 has narrated in paper the method that produces the simulation watermark, and the composition of the scraps of paper with transparence is immersed in the needed watermark pattern, and this composition begins polymerization during by UV-irradiation and forms the simulation watermark.

US-A-5118526 has narrated a kind of method of producing the simulation watermark, is that on demand watermark figure imposes on heat on the thin waxy solid matrix, and this matrix contacts with the scraps of paper, and the result has produced the impression of durable translucent watermark.

US-A-4513056 relates to dipping in special transparent resin is bathed, and heating makes resin crosslinks then, gives paper all or part of transparent method.

EP-A1-0388090 has narrated an a kind of perspective or print through feature method that the zone combines with the paper with basic uniform transparency, and this part is more more transparent than remaining major part of paper.

JP-61-41397 discloses the production method that makes transparent method of paper and window envelope.The method utilizes ultraviolet light to carry out the effect of crosslinked generation printing ink to infiltrate paper, therefore make this part paper become transparent, all these provide the method that strengthens anti-counterfeiting characteristic all to be used for finished paper and non-banks and non-cheque paper, and they can be used for the paper of wood pulp based to use as a large amount of commerce.Such matrix is still very porous, and itself anti-oil or fat are less, and can successfully make it have the transparency.Moreover, in this application, wish the step of transparence as an independent technology especially.Because a certain amount of loss is arranged in the paper-making process, additional and method normally should be avoided in conjunction with one again in paper-making process, preventing to increase loss.There is not a kind of prior art can be more suitable for hanging down the paper of absorbability and low-porosity, as bank-note paper.Such paper generally is treated to reduce the absorption of oily matter and organic solvent as far as possible.Reach this purpose, general use the fibre substrate that designs for the porosity that reduces paper and paper is flooded with gum resin on any such as polyvinyl alcohol or gelatin, and with the paper calendering.Gluing and press and smooth the porosity that the friendship process helps to reduce paper.When finished paper is handled in this way, can not make its transparence, because of its absorptivity low stopping the infiltration of transparent resin.If with the resin or the requirement of ultraviolet curing one heated drying process is arranged, the water capacity of paper is interfered, and this may be exactly the reason that produces printing paper feed (runability) problem at printing stage.

A purpose of the present invention (also being described in simultaneously in the common pending application of submitting to) provides a kind of method of papermaking, and it is transparence that this paper has a part at least, with false proof or an anti-counterfeiting characteristic that strengthens is provided when duplicating.

Another scheme of improving anti-counterfeiting characteristic in paper is to utilize the optical property of surperficial iris.

EP-A-O, 493,231 have narrated a kind of printable paper of making security document, have a kind of iris coating on the part surface at least of paper at least.Coating composition is made up of a kind of adhesive such as polyvinyl chloride and a kind of iris material at least, and coating imposes on the finished paper.

FR-A-2,641,011 also disclose printable paper, comprise the coating that one deck is made of a kind of iris material at least in its surface.Coating is deposited on the finished paper with the gravure print process, the printing ink that uses varnish and iris material to form.

EP-A-0,490,825 have also narrated a kind of cheque paper, and its surface color coating is made up of at least two kinds of surface areas that become band that adjoin, and coated tape contains different rainbow pigment, when can present different colors when the range of view angles of at least one inclination is observed.

Formerly have in the technical method, the rainbow coating that the paper transparence is adopted only is applicable to is not having the finished paper that absorption and low porosity paper were handled.

An object of the present invention is to provide a papermaking process, make at least a portion transparence of paper and iris is arranged, with the antifalsification that the imitated of enhancing is provided and duplicates.

Must understand, " security document " speech comprises banknote, check, passport, identity card, stock, ration card, ticket etc.

Also must understand simultaneously, " iris material " speech is meant the material that can produce color change through catoptrical interference effect before and after the film in its telogenesis.

Now also with reference to the accompanying drawings optimum implementation of the present invention is described in detail with embodiment.In the accompanying drawings:

Fig. 1 is the cutaway view of the equipment that uses in the papermaking process of the present invention;

Fig. 2 is another used equipment cutaway view of papermaking process of the present invention;

Fig. 3 is the perspective view of the rotary screen press among Fig. 1;

Fig. 4 is by low security file signal of making of the present invention;

Fig. 5 is another security file signal of being made by paper of the present invention;

Fig. 6 is the transversal lateral elevational view of Fig. 4 file along VI-VI line amplifier section.

Referring to Fig. 1, cylinder mould machine 10 comprises the groove 11 that contains paper pulp, and paper pulp is the suspension of paper fibre 12.The major part of the cylinder 13 of horizontal positioned immerses groove 11, and there is the metal cylinder mould on the surface of cylinder 13, can be embossing, and generally adopting which floor cylinder mould, outermost one deck is the thinnest, when cylinder 13 rotations, liquid sucks by wire netting, makes paper fibre be deposited on the net and form l Water Paper layer 14.With couch roll 15 l Water Paper layer 14 is taken off from tube, on the metal cylinder mould 16 of motion, passed.

L Water Paper layer 14 passes through wet press roll 17 then with extruding ply of paper 14, removes unnecessary water, then that paper 14 is dry on the tube 19 of heating.

Though the present invention is described with cylinder mould machine, this is a method for optimizing, and the method that forms paper can be finished with other many methods, and the most normally used other method is with fourdrinier machine shown in Figure 2.In this paper machine, from the paper pulp medicine applying apparatus or flow out the fibre pulp that box 30 flows out and deposit on the screen cloth 31 of a continuous motion.Water in the fibre stuff is through screen cloth 31 and diafiltration, and the dehydration fibrage 32 that obtains wetting, fibrage 32 pass through for 33 times at dandyprat, stamp the convex watermark.Then l Water Paper is passed through wet press roll 34, carry out drying again.

In traditional papermaking process be with paper with gum resin on any such as polyvinyl alcohol (PVOH) or gelatin dipping to reduce the absorption of oily matter or organic solvent as far as possible, the scraps of paper 14 bathe 18 by a gluing makes its gluing saturated.The paper that obtains like this is therefore with regard to the anti-grease of energy, and absorbability is very low, relatively is suitable as bank-note paper etc.After this scraps of paper 14 are passed through an air floating trough or other suitable drying machine 20 with further drying, before reel 22, make it smooth surface then by a calender apparatus 21.

According to modification method of the present invention, the transparent resin that will contain the iris material with silk screen print method or other resin medicine applying apparatus imposed on its surface before the scraps of paper 14 that part forms enter gluing bath 18.Details is shown in Fig. 3.Screen process press 23 is printing machines of a rotation, it comprises the cylindrical shape silk screen that is installed in the hard flexible metal screen cloth on steel framework, cover on it to leak card 24, need leak in the card with an opening 25 at the pattern that reappears on the paper and form, when the scraps of paper pass through cylinder, transparent resin 26 promptly imposes on the inboard of metallic sieve, and forces it to reach on the scraps of paper 14 by metallic sieve with extruding cutter 27.

The ground that some paper can suit is handled with gravure, aniline seal or other method, and without silk screen print method.

The transparent resin amount of using in the printing process is at least 5%(weight) in the scraps of paper of part formation.In the concrete scheme of the best of the present invention, the amount of application of resin is at least 10%(weight).

The paper that this moment, part formed is the most absorbent, therefore makes transparent resin that good permeability is arranged.Without solidification process, the scraps of paper 14 directly are admitted to gluing and bathe 18 in a specific embodiments of the present invention.In place with regard to effectively the transparent resin that flows being solidified like this, prevented the pollution of transparent resin.This effect is unexpected, enters gluing once the scraps of paper 14 and bathes 18, and sizing material just is filled in the hole that contains transparent resin paper on every side, has therefore prevented the transfer of transparent resin.Transparent resin just can impose in the zone of obvious qualification of paper, thereby the integral body and the personation performance of the security document that paper is made enough provide a transparent region or pattern.Security document can be banknote, check, passport, identity card, stock etc.The example of the security document of manufacturing with the method is illustrated among Fig. 4, has wherein shown the translucentization district 28 that clearly limits.Should be noted that transparence regional reflex light does not have the paper of nontransparentization many, thereby the profile in transparence district can see too clearly in reverberation.

The iris material is added transparent resin, in reflection and transmitted light, all have the cooperative effect of not expecting.Paper moved and in reverberation, check and to see a different colo(u)rimetric shift.Can't see coloured change though only in reverberation, change observation angle, when light when transmitted light is converted to reverberation, can see that also a different colo(u)rimetric shift is arranged.

This effect can make an explanation with Fig. 6.When the resin 40 that contains iris material grains 41 is coated on the paper 14,40 holes that infiltrate through paper 14 of resin.But the granularity of iris material grains 41 is greater than the hole of paper, thereby can not infiltrate the scraps of paper, and particle 41 is just with staying in the superficial layer with cambial a part of resin 40a on paper 14 surfaces.Therefore this resin has double action: the effect of infiltrating the resin generation transparence in the paper; The resin of staying paper combines with the iris particle and forms the iris coating.Because having shown, it knows and different effects that this just provides higher anti-counterfeiting ability to security document.

In another concrete scheme of the present invention, resin available electron bundle (EB) or ultraviolet (UV) radiation are solidified with " fixing " resin, and curing takes place after resin-coated soon and before the scraps of paper 14 being sent into gluing bath 18.The advantage of these resins is, they just are fixed and control once solidifying.

The processing space that printing machine 23 and gluing are bathed between 18 can be restricted.In another specific embodiments of the present invention, resin is that the paper 14 that forms in part is by drier 20 be cured before calender.Be transformed on the roller of gluing bath in order to prevent transparent resin, before paper enters gluing bath 18, carry out precuring in short-term, resin surface is solidified prevent transfer, just remaining resin " is fixed " after photoresist coating process is finished in the paper body.

In addition, can between air flotation drier and calender, carry out crosslinking with radiation to provide the long period to transparent resin with the infiltration scraps of paper 14.

When producing paper, in method, can adopt the binomial supplementary technology, so that increase the absorbability of 14 pairs of transparent resins of the scraps of paper with said method.

Resin can impose on the low gram fractional part of the paper of making by known modelling or dandy roll watermark method, and consequently the effect of watermark greatly strengthens, because the clear zone of watermark and dark space contrast have increased widely.Under the situation of molded watermark, it also has the advantage of creating the low regional area of a light tight pigment (as titanium dioxide), has further improved the transparence effect of transparent resin.Under the situation of molded watermark, this also has the advantage that can form the low regional area of light tight pigment (as titanium dioxide), and this can further strengthen the transparence effect of transparent resin, and therefore also increases the chromatic effect of iris material.

Transparent resin also can be applied to decorates watermark 29, as shown in Figure 4, rather than resin is applied to the low gram fractional part of paper, this has greatly enlarged the use of transparence and iris feature, to increase its visual complexity significantly and to result from easy identity wherein and be difficult to replicated image, with the deterrence imitator.

When translucence is controlled in when being not less than 50% obscurity, the observability of watermark profile has improved, and this does not expect.

In another specific embodiments of the present invention, with Fig. 5 explanation, resin can be used as around the profile or the housing of the low gram fractional part of watermark 37 and paper, and this has the effect of notice being guided into watermark.

In addition, perhaps except the purposes of relevant watermark, transparent resin can impose on the striped of paper.With cylinder mould machine 10 papermaking the time, the usable fibers placer is placed into certain position of mould with dissimilar fibers, makes streaky effect on the paper that obtains.These dissimilar fibers can produce the paper structure than porous.The generation of this striped has makes transparent resin than the paper around it better absorption be arranged, and therefore just can be used to improve transparent effect.

In addition, can in transparent resin and iris material, add fluorescigenic dyestuff.This has very important commercial effect, and when just making its fluorescence that transmission is arranged with uviol lamp, this fluorescence only produces in reverberation usually.

Fluorescigenic transparent resin can also be applied to ornamental watermark.Its result has the feature that shows its watermark shade when observing in ultraviolet transmission light, this is the effect of not expecting, and because its tangible outward appearance, it is useful anti-counterfeiting characteristic.

In another specific embodiments of the present invention, can strengthen the effect of transparent resin with the gravure process that is known as the paper embossing.Heat, pressure combination used in woodburytype have improved the distribution of resin through paper, but except non-thermoplastic resin such as the radiation cure type resin.

In the high cheque paper of quality, add traditional titanium dioxide or another and make opaque pigment with the perspective that reduces trace or penetrate, and reduce unwanted paper as far as possible and fluoresce.In order to increase the transparence effect of resin as far as possible, preferably remain on the titanium dioxide level among the present invention minimum.

In another specific embodiments of the present invention, register with the rainbow feature with machine and horizontal watermark.Unregistered feature has its technical simple advantage, but in like manner, it is easy to a large amount of imitations more significantly than the feature of registering, and this crosses range request and uses up the position of learning detector evaluation watermark, and this feedback information is given the electronic installation of control printing screen (under the situation of serigraphy) driving.In addition, in other printing process, the silk screen Tension Control can be to finish the mechanism of registration.

Be suitable for to discuss below with the raw material of papermaking of the present invention and the example of composition.

Paper fibre

The paper that is suitable for banknote and security file is made with various fibers, as flax, abaca, wood pulp, cotton and their mixture.Wood pulp is usually used in non-banknote security document, and cotton is preferred making paper currency fiber.These cottons are usually from obsolete material, as the leftover pieces of textile industry.Finished fiber has band like form, and higher surface/surperficial contact area is arranged.But produce the cotton fiber that is suitable for making paper currency paper etc., fiber must be made with extra care from its original tubular configuration through the machining of short dirty fiber of past, in order to obtain high-quality basic paper, must guarantee carefully to be prepared, operate and go to lack dirt to obtain only length and draining characteristics, also kept the necessary high strength of paper simultaneously to obtain the high-quality watermark.This paper is that the fiber of 45-70 is made by schopper Riegler value normally.Although its processing is meticulous, fiber is that natural fabric and each batch possibility are different, obtains the different paper of porosity.The specification difference that different user requires also can change porosity.

Last gum resin

Must note, the last gum resin of indication of the present invention is the surface sizing resin, rather than the inner gum resin of going up, preferably traditional last gum resin, such as polyvinyl alcohol (PVOH) or gelatin, say that from function they generally are the most successful, but also have other many chemicals to use, as starch or emulsion based polymer.

Because the paper quality of fiber changes, so gum concentration also can change in process.

Transparent resin

As mentioned above, transparent resin can be known ultra-violet curing, non-curing and crosslinkable resin.

Transparent resin is printed to the method on the scraps of paper 14 and this resin absorbed the time required in the paper through the serigraphy art, except some other factor, be decided by the viscosity of resin.Because the speed of paper machine running is different and the character of basic paper fiber may be different, thus the viscosity of necessary control resin, so that the transparency of control paper.Therefore be recommended in two kinds of resins at viscosity spectrum two ends, they are mixed, be formed with the resin of the viscosity of suitable machine speed, the transparency level that is reached and infiltration rate etc.Another system of selection also is wetting agent such as the FC-430 Fluorad(trade mark that adds varying level) (, being a kind of fluoro aliphatic polyester) by the 3M supply.Thereby, if basic paper porosity is lower than desirable, this wetting agent can and mixed with resin, and add in the serigraphy stage.

The penetration degree of resin can wait according to amount of resin, the time of staying, the absorption rate used and control.

The resin of UV curable-preferred resin is 100% resin, and solubilizer, its refraction index be not about 1.5, and the viscosity in the time of 23 ℃ is the 400-1500 centipoise.It is not flavescence and transparent that resin preferably should be.When curable hardening of resin, the requirement of suitable physical strength also must be arranged, for example they can not be fragility.

The example of this resin is a Photomer 4061(trade mark), it is the diacrylate of tripropylene glycol, and Photomer 5018(trade mark), it is the third Xi acid polyester of four functional groups, and the two is by Harcros Chemical(Britain) company's supply.These two kinds of resins are the opposite ends that are in the viscosity spectrum, can be used in combination to provide the suitable transparent resin of proper viscosity.

The physical criterion of the non-cured resin of non-cured resin-suitable basically with the resin of ultra-violet curing require identical, the material that is fit to comprises polybutene class material, such as Hyvis 7(trade mark), it is polyisobutene (BP Chemicals), and Hyvis 5(trade mark), also be the polyisobutene of BP Chemicals supply.Hyvis 5 is than the viscosity height of Hyvis 7.

It should be noted that non-cured resin generally is liquid, has not required material intensity.But be purpose of the present invention,, remain on suitable place with the surface that iris will be arranged as then being the resin that can become solid matrix with non-ultraviolet-curing resin.

Crosslinkable resin-suggestion also can be used such as epoxy resin and alkyd resins.But importantly this resinoid hardening time is longer.If also do not change when paper bobbin, whole coil paper will stick together, and resin transfer perhaps can take place go to adjacent paper.

When using non-curing and crosslinkable resin, its amount must careful control.In fact this resinoid does not solidify.Importantly paper and unsaturation, it can be left a trace on the adjacent paper on the paper roll.

The iris material

The preferred iris material of iris material is the IRIODIN(trade mark), it is with titanium dioxide (TiO ₂) the mica small pieces that apply, provide by Merck AG.The color range of this material depends on TiO ₂Coating layer thickness, the granularity of titanium dioxide is about the 5-100 micron.

In an example of the banknote of making by paper of the present invention, the amount that adds the small pieces in the resin be resin heavy 40%.

Claims

1, a kind of papermaking process may further comprise the steps: with fiber laydown on area supported to form porous and absorbent paper; The composition that will contain the transparent resin of iris material imposes at least a portion of said porous paper; Use gum resin dipping porous paper then.

2, the method for claim requirement, the amount of composition that wherein imposes on porous paper is at least 10%(weight).

3, claim 1 or 2 method, the amount of composition that wherein imposes on porous paper is at least 10%(weight).

4, the method for aforementioned each claim, wherein using composition is to use silk screen print method.

5, the method for aforementioned each claim, wherein transparent resin is a resin non-curing or crosslinkable.

6, each method of claim 1-4, wherein transparent resin is the curable resin that available ultraviolet or electron beam irradiation are cured.

7, the method for claim 6, this method are carried out the step of ultra-violet radiation with the curing transparent resin with porous paper before further being included in and using the gum resin dipping.

8, the method for aforementioned each claim, this method further are included on the porous paper to form low gram number area and composition is imposed on the said low gram of at least a portion counts step on the area.

9, each method of claim 1-7, this method further are included in the step that forms a low gram number area on the porous paper and use composition at the edge that said low gram is counted area.

10, claim 8 or 9 method, wherein low gram number area is a watermark.

11, the method for aforementioned arbitrary claim, this method further are included on the porous paper and produce a dissimilar fibrous ribbon and composition is imposed at least a portion of said band.

12, the method for aforementioned arbitrary claim wherein adds fluorescigenic dyestuff in composition.

13, the method for aforementioned arbitrary claim wherein adds wetting agent in composition.

14, the method for aforementioned arbitrary claim is wherein controlled to control the transparency of paper the viscosity of transparent resin.

15, the method for aforementioned arbitrary claim, this method further comprise with heat and press and combine with the step of embossing on paper.

16, the method for aforementioned arbitrary claim, this method further comprises the step of calendering sized paper.

17, the paper of producing with the method for aforementioned each claim.

18, comprise at least one zone paper of transparence, further be included at least one the iris coating on the partially transparent zone at least, when in transmission or reverberation, observing, present different colors.

19, the described paper of claim 18, its floating coat comprises the transparent resin that contains the iris material.

20, claim 18 or 20 described paper, wherein the iris material comprises mica particles.

21, by security document each described paper production of claim 17-20 or that comprise said paper.

22, a kind of equipment that comprises the papermaking of the equipment that forms paper, comprise fiber laydown device with the formation porous and absorbent paper on area supported, the composition that will contain the transparent resin of iris material imposes on the device of at least a portion of this paper, gluing resin bath, and the device of this porous paper of transmission therebetween.

23, a kind of basically as above-mentioned and with accompanying drawing papermaking process for referencial use.

24, basically as above-mentioned and be the paper of reference with the accompanying drawing.

25, basically as above-mentioned and be the paper making equipment of reference with the accompanying drawing.