EP0219743A1 - Security paper containing vesiculated beads - Google Patents

Security paper containing vesiculated beads Download PDF

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Publication number
EP0219743A1
EP0219743A1 EP19860113634 EP86113634A EP0219743A1 EP 0219743 A1 EP0219743 A1 EP 0219743A1 EP 19860113634 EP19860113634 EP 19860113634 EP 86113634 A EP86113634 A EP 86113634A EP 0219743 A1 EP0219743 A1 EP 0219743A1
Authority
EP
Grant status
Application
Patent type
Prior art keywords
paper
beads
security paper
recited
vesiculated beads
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.)
Withdrawn
Application number
EP19860113634
Other languages
German (de)
French (fr)
Inventor
Robert H. Hamilton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
DeSoto Inc
Original Assignee
DeSoto Inc
Priority date (The priority date 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 date listed.)
Filing date
Publication date

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Classifications

    • DTEXTILES; PAPER
    • D21PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21HPULP 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
    • D21H21/00Non-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
    • D21H21/14Non-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
    • D21H21/40Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
    • D21H21/44Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
    • D21H21/48Elements suited for physical verification, e.g. by irradiation

Abstract

Security paper contains polymeric vesiculated beads having a volume average particle size of at least about 10 microns up to about 35 microns, these beads containing dye or pigment which glows when irradiated with nonvisible radiation, and being hard to see when the paper is viewed with the naked eye under normal visible light.

Description

    Technical Field
  • This invention relates to security paper containing vesiculated beads which are not visible when viewed by visible light, but which are easily seen when exposed to nonvisible radiation.
  • Background Art
  • Special papers have been developed for security purposes to help insure that the document is genuine. These papers are illustrated by the use of colored fibers, planchettes, water marks or special dyes. It is desired to provide papers which will be more difficult for the counterfeiter to duplicate. The special character of some of these papers is easily seen by close inspection under ordinary light, so anyone viewing the paper is alerted to the need for using a paper having a special appearance, and it is not too difficult to provide a duplicate paper. In some instances a special light is needed to see a dye in the paper, but it is still not too difficult to provide a paper containing a comparable concentration of the same dye. It is desired to provide security paper which contains very easily visible identification when viewed by nonvisible light, whereas this identification is not visible when the paper is viewed under normal lighting. In this way, one attempting to mimic the document may not be alert to the fact that ordinary paper cannot be used. Moreover, it is desired to provide paper which is not easily duplicated even when the party attempting to mimic the document is alert to. the fact that the paper has a peculiar appearance under nonvisible light.
  • It is also important to provide a paper which is economically producible, which is printable, as by engraving processes, without damage, and which can be viewed to insure its genuine nature from either side of the paper.
  • Disclosure of Invention
  • In accordance with this invention, there is incorporated into the paper furnish, cross-linked, polymeric vesiculated beads having a volume average particle size of at least about 10 microns, preferably at least 20 microns, up to about 35 microns, and which include pigment or dye which responds to nonvisible radiation, especially to ultraviolet light. These polymeric vesiculated beads are small enough so that they are not visible to the unaided eye, even when these beads are colored when so viewed and incorporated into white paper. However, under nonvisible light, these beads glow and provided bright spots (which may have a distinctive coloration or combination of colorations) to identify the paper and distinguish it from ordinary paper as well as other special papers having a different density of bright spots and/or spots of different coloration.
  • In preferred practice, the security paper will contain from 0.1 to 15 weight percent of such beads, preferably from 0.5 to 5% thereof, based on the total weight of the paper. This paper may be calendered or uncalendered.
  • It is desired to point out that prior security papers are frequently single sided in that the fibers or other identifying devices concentrate at the wire side of the paper. In this invention, the beads which are incorporated in the paper become visible under nonvisible light at both sides of the paper, and this eases the burden of examination.
  • It is stressed that the vesiculated beads under consideration contain many cells and are quite different from ordinary hollow polymer beads in being load bearing. As a result, these beads can be present in paper which sustains the pressure of the calendering and engraving processes which are involved in the production of security papers.
  • The beads under consideration normally contain an average of at least about 5 cells per bead, preferably at least about 10 cells per bead. It appears that the presence of a large number of cells in each bead is what allows the bead to avoid collapse when paper containing the same is compressed under the considerable force imposed in the calendering operation.
  • It is stressed that the beads in this invention have transparent walls, and the multiplicity of cells retroreflects the incident light to produce a very bright spot of emitted light when the paper is appropriately irradiated. It is very difficult to duplicate the brightness of the vesiculated beads using plastic beads of different character. Moreover, the most effective way to provide the beads which are used herein is to incorporate the pigment or dye into the cell walls at the time of their production, and it would be very difficult to add a corresponding coloration after the beads have been formed. It is unlikely that one attempting to duplicate a security paper would be able to mimic the beads which are used herein.
  • It is also stressed that the appearance of invisibility in ordinary light and easy visibility in nonvisible light is an aspect of the fact that the beads are uniformly distributed throughout the body of the paper. This uniform distribution of the beads throughout the body of the paper requires that the vesiculated beads be added to the paper furnish. It is found that when the beads are so added, they are effectively retained in the paper as the water and some of the fines and mineral filler used in papermaking pass through the Fourdrinier wire in conventional papermaking.
  • Bead retention can be enhanced when conventional retention aids are employed, though this is not essential. Both anionic and cationic retention aids are useful, but anionic retention aids are more efficient. The vesiculated beads are distributed quite uniformly throughout the paper and, while many of them are buried within the paper so as to be invisible on casual inspection, they will nonetheless pick up nonvisible light and glow in the visible range to provide a bright spot which is easily seen.
  • The retention aids which have been found to be useful herein are themselves well known, and many are available in commerce. Acrylamide and methacrylamide copolymers with monoethylenic acids or monoethylenic amines are preferred, these generally containing from 5% to 50% of the acid or amine monomer, balance the amide monomer. The anionic copolymers which are preferred will usually contain acrylic or methacrylic acid as the acid component, and these are rendered anionic with the aid of an amine, which is preferably ammonia. Thus, a copolymer of 20% methacrylic acid with 80% acrylamide is illustrative of a preferred anionic retention aid.
  • The cationic amide copolymers are illustrated by copolymers of acrylamide with diethyl aminoethyl methacrylamide.
  • Various other anionic and cationic resins which may be used as the retention aid are discussed in the Kirk Othmer "Encyclopedia of Chemical Technology, third edition" Volume 16, at page 804 which points out that the usual fillers having a size up to 5 microns are not effectively retained because they are so small, thus provoking the use of retention aids in the paper furnish. The beads used herein are generally much larger, but their retention on the Fourdrinier wire is enhanced by the conventional retention agents nonetheless.
  • The preferred vesiculated beads are styrene-cross-linked unsaturated polyester resins. These are made into a vesiculated bead in conventional fashion, as illustrated by U.S. Pat. No. 3,879,314. The size of the vesiculated beads under consideration may vary considerably, but is generally larger than a volume average of about 10 microns in diameter. For example, beads having a volume average diameter of from about 10 to about 35 microns are conveniently prepared and fully useful in this invention. As the bead size increases above about 20 microns, they become particularly easy to see when properly exposed, and are thus preferred for use herein.
  • Various other patents are of interest to the formation of vesiculated beads useful in this invention, particular attention being directed to U.S. patents Nos. 3,822,224, 3,923,704 and 3,933,579. This last-named patent describes the vesiculated beads which are preferred herein, namely, those having a ratio of granular diameter to mean vesicle diameter of at least 5:1, a vesicle volume of from 5% to 95% of the volume of the granule, and not more than about 60o pigment, by volume.
  • The vesiculated beads used herein have a highly cross-linked polymeric body which is preferably constituted by a carboxyl-functional unsaturated polyester resin cross-linked with an ethylenically unsaturated monomer copolymerizable therewith. The unsaturation in the polyester is preferably maleate unsaturation, these polyesters being themselves well known and illustrated hereinafter. It is preferred that the polyester have an acid value of 10 to 45 mgm KOH per gm.
  • The unsaturated monomers used for cross-linking are also well known and are water insoluble monomers typically illustrated by styrene or vinyl toluene. The polyesters and monomers are more fully discussed in U.S. Pat. No. 3,879,314 which shows the production of vesiculated beads using a water-soluble polyamine containing at least three amine groups per molecule and having a dissociation constant in water (pKa value) of 8.5-10.5, typically illustrated by diethylene triamine. The polyamine is used in a concentration providing at least 0.3 amine groups per polyester carboxyl group, usually from 0.5 to 1.4 amine groups per polyester carboxyl group. It is preferred to have from 35% to 45% of the unsaturated polyester cross-linked with from 55% to 65% of styrene.
  • The invention is illustrated as follows, it being understood that all parts and proportions are by weight, unless otherwise specified.
  • Example
  • Suitable pigmented vesiculated beads in accordance with this invention are illustrated in U.S. Patent No. 3,879,314 issued April 22, 1975, see particularly Example II. By proceeding in accordance with said Example II and using a polyester of 18% phthalic anhydride, 37% maleic anhydride and 45% propylene glycol dissolved in styrene to form a solution containing 41.8% of the polyester, vesiculated beads pigmented with a pigment which glows when irradiated with ultraviolet light, to contain about 19.0% pigment, by volume, are provided. These beads have an average size of about 25 microns and contain an average of more than 10 cells per bead.
  • These beads are typically incorporated into a paper furnish in which 800 pounds per ton of softwood kraft, 1200 pounds per ton of hardwood kraft, 300 pounds per ton of clay, 20 pounds per ton of rosin size, and 30 pounds per ton of alum are mixed into water to a consistency of about 3%. The pH is adjusted to a pH in the range of 4.5 to 6.5 by the addition of concentrated sulfuric, and this provides the furnish which is modified by the addition of beads in this invention. The above proportions are in pounds per ton of finished paper basis. This furnish is modified to include 4% or 6% of the vesiculated beads and 1.5% of titanium dioxide, anatase, based on solids content and is supplied to the head box by passing the mixture through a valve in which the solids concentration is reduced to 1.5%.
  • The paper made from this bead-containing furnish had a basis weight in the range of 37 to 40 pounds per ream, and it was passed through a size press in conventional fashion and then calendered at either 150 or 900 pounds per linear inch at a temperature of about 150°F. to provide a printable paper. This paper, when viewed with ordinary liglit, appeared to be an ordinary paper, but when viewed with ultraviolet light was seen to have glowing spots all over it, like salt scattered on black paper.

Claims (10)

1. A security paper containing polymeric vesiculated beads having transparent walls and a volume average particle size of at least about 10 microns up to about 35 microns, said vesiculated beads containing dye or pigment which glows when irradiated with nonvisible radiation, and said vesiculated beads being hard to see when the paper is viewed with the naked eye under normal visible light.
2. A security paper as recited in claim 1 in which said vesiculated beads have a volume average particle size of at least about 20 microns.
3. A security paper as recited in claim 1 in which said vesiculated beads are present in an amount of from 0.1% to 15% and contain an average of at least 5 cells per bead.
4. A security paper as recited in claim 3 in which said vesiculated beads have a ratio of granular diameter to mean vesicle diameter of at least 5:1, a vesicle volume of from 5% to 95% of the volume of the granule, and not more than about 60% pigment, by volume.
S. A security paper as recited in claim 1 in which said vesiculated beads are incorporated in the furnish to be relatively uniformly distributed throughout the body of the paper.
6. A security paper as recited in claim 5 in which said paper is calendered.
7. A security paper as recited in claim 5 in which the polymeric body of said beads is constituted by a carboxyl-functional unsaturated polyester resin cross-linked by an ethylenically unsaturated monomer copolymerizable therewith.
8. A security paper as recited in claim 7 in which from 35% to 45% of unsaturated polyester containing maleate unsaturation is cross-linked with from 55% to 65% of styrene.
9. A security paper as recited in claim 1 in which said pigment or dye is associated with the walls of said cells.
10. A security paper as recited in claim 1 in which said vesiculated beads are present in an amount of from 0.5% to 5%.
EP19860113634 1985-10-04 1986-10-02 Security paper containing vesiculated beads Withdrawn EP0219743A1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
US78462085 true 1985-10-04 1985-10-04
US784620 1985-10-04

Publications (1)

Publication Number Publication Date
EP0219743A1 true true EP0219743A1 (en) 1987-04-29

Family

ID=25133025

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19860113634 Withdrawn EP0219743A1 (en) 1985-10-04 1986-10-02 Security paper containing vesiculated beads

Country Status (3)

Country Link
EP (1) EP0219743A1 (en)
CA (1) CA1282913C (en)
FI (1) FI864014A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4863783A (en) * 1985-12-05 1989-09-05 The Wiggins Teape Group Limited Security paper
EP1074599A1 (en) * 1998-12-25 2001-02-07 Tokushu Paper Manufacturing Co. Fluorescent particle, method for preparing the same and paper for preventing forgery using the fluorescent particle
WO2002046528A1 (en) * 2000-12-05 2002-06-13 Spectra Systems Corporation Fluorescent micro-particles embedded in a pigmented fluorescent coating for optical document security
WO2002078964A2 (en) 2001-04-02 2002-10-10 Giesecke & Devrient Gmbh Colour coding system for identifying objects
EP1342768A1 (en) * 2000-11-22 2003-09-10 Tokushu Paper Manufacturing Co. Ltd Particles emitting fluorescence by irradiation of infrared ray and forgery preventing paper using the same
WO2004101890A1 (en) * 2003-05-19 2004-11-25 Merck Patent Gmbh Dual security mark
FR2868093A1 (en) * 2004-03-26 2005-09-30 Honnorat Rech S & Services Sar Coated security paper comprises an authenticatable layer that provides a specific printability characteristic and authenticatable spots that are visible under ultraviolet illumination

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3933579A (en) * 1968-11-28 1976-01-20 Dulux Australia Limited Vesiculated polymer granules
GB1528193A (en) * 1974-09-10 1978-10-11 Hoechst Ag Thermoplastic sheet containing irradiation-converting particles
FR2478695A1 (en) * 1980-03-21 1981-09-25 Aussedat Rey Security paper incorporating dispersed luminescent particles - visible only in UV light, prepd. by adding particles suspension to finished pulp

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3933579A (en) * 1968-11-28 1976-01-20 Dulux Australia Limited Vesiculated polymer granules
GB1528193A (en) * 1974-09-10 1978-10-11 Hoechst Ag Thermoplastic sheet containing irradiation-converting particles
FR2478695A1 (en) * 1980-03-21 1981-09-25 Aussedat Rey Security paper incorporating dispersed luminescent particles - visible only in UV light, prepd. by adding particles suspension to finished pulp

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4863783A (en) * 1985-12-05 1989-09-05 The Wiggins Teape Group Limited Security paper
EP1074599A1 (en) * 1998-12-25 2001-02-07 Tokushu Paper Manufacturing Co. Fluorescent particle, method for preparing the same and paper for preventing forgery using the fluorescent particle
EP1074599A4 (en) * 1998-12-25 2001-10-17 Tokushu Paper Mfg Co Fluorescent particle, method for preparing the same and paper for preventing forgery using the fluorescent particle
US6663960B1 (en) 1998-12-25 2003-12-16 Tokushu Paper Mfg. Co., Ltd. Fluorescent particles, method for preparing the same and paper preventing forgery using the fluorescent particle
EP1342768A1 (en) * 2000-11-22 2003-09-10 Tokushu Paper Manufacturing Co. Ltd Particles emitting fluorescence by irradiation of infrared ray and forgery preventing paper using the same
EP1342768A4 (en) * 2000-11-22 2003-09-10 Tokushu Paper Mfg Co Ltd Particles emitting fluorescence by irradiation of infrared ray and forgery preventing paper using the same
WO2002046528A1 (en) * 2000-12-05 2002-06-13 Spectra Systems Corporation Fluorescent micro-particles embedded in a pigmented fluorescent coating for optical document security
WO2002078964A2 (en) 2001-04-02 2002-10-10 Giesecke & Devrient Gmbh Colour coding system for identifying objects
DE10116315A1 (en) * 2001-04-02 2002-10-10 Giesecke & Devrient Gmbh Color coding to identify Gegentänden
WO2004101890A1 (en) * 2003-05-19 2004-11-25 Merck Patent Gmbh Dual security mark
US7713616B2 (en) 2003-05-19 2010-05-11 Merck Patent Gmbh Dual security mark
FR2868093A1 (en) * 2004-03-26 2005-09-30 Honnorat Rech S & Services Sar Coated security paper comprises an authenticatable layer that provides a specific printability characteristic and authenticatable spots that are visible under ultraviolet illumination

Also Published As

Publication number Publication date Type
FI864014A0 (en) 1986-10-03 application
FI864014A (en) 1987-04-05 application
CA1282913C (en) 1991-04-16 grant
FI864014D0 (en) grant

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Kind code of ref document: A1

Designated state(s): DE GB NL

18D Deemed to be withdrawn

Effective date: 19871030

RIN1 Inventor (correction)

Inventor name: HAMILTON, ROBERT H.