FR2618812A1 - ANTICOPIA PRINTING-WRITING MEDIUM AND METHOD THEREOF - Google Patents

Abstract

Printing-writing medium intended to render any photocopy which does not conform to the original or illegible, of the type comprising compounds comprising at least one photochromic intended to disturb the radiation reflected by the medium during the photocopying operation. The photochrome is individually incorporated into the support.

Description

ANTICOPIA PRINTING-WRITING MEDIUM AND METHOD THEREOF

  The present invention relates to the protection of authentic documents (confidential, secret ...), titles, negotiable documents or not, all or part of valuable publications (books, journals, report, ...) or any other document against

  copies, among others fraudulent, using pho-

  tocopier, for example of the electrostatic or xerographic type.

  Because of the easy accessibility to xerographic or electrostatic copying machines, and in view of the simplicity of use and the low reproduction costs, there is more and more widespread copying of unauthorized and non-authorized documents. discriminatory. Such processes are prejudicial to the authors of the documents allowing for example the

  disclosure of secrets or violating the legal rights of these authors.

  In what follows, we will designate by original document all that will be the object of a photocopy. This original document is

  consisting of a macromolecular support with an informa-

  graphic design (texts, drawings, ...). The graphic information has been deposited on or in the medium by any of the techniques

possible graphic art.

  Many French and foreign patents disclose ways of mitigating these unwanted copying. Thus, it has been proposed to use highly colored special papers (CA-A-1187914 and US-A-3 887 742) as originals; such papers are marketed; however the contrast in this case between

  the graphic information and the color of the special papers is

  This makes the original document difficult to read and may in the long run result in significant or even unacceptable visual fatigue. Non-exhaustive examples of other patented means which have not yet been manufactured

  Industrial: original reflective documents (metallic papers

  original, luminescent documents, particular markings,

  photochromic documents, ... We are particularly interested in

  photochromic materials made from photochromic substances

  nomic. It is known that these photochromic substances (or by abbreviation photochromic) have the property of giving a color

  reversible to the support under the influence of electro-

  magnetic ultraviolet or visible (of a general wavelength

  200 to 800 nm). By the use of such a substance, it becomes possible to have an original whose information

  graphic is distinguished from the background by a very strong visual contrast.

  under normal lighting but the background of which takes a very clear coloration under adequate irradiation. We can refer to

  GB-A-1 227 201, US-A-3 597 082, DE-A-2 419 278.

  However, it has been found in the context of the present invention that certain photochromes can interact with the document medium (film, paper, etc.). Thus, for example, spiropyrans react with cellulose or paper additives to give, either by chemical bonding or by solvation, or by physicochemical interaction (absorption, Van der Walls bonds, ...), photochromic systems that are difficult to control. (coloring, ...) or non-photochromic. It is easy to imagine that by using these photochromes as they are, it is

  difficult to obtain reliable industrial processes.

  The object of the invention is to propose a new means of making any photocopy non-compliant with the original, or illegible, using the photochromic substances but not presenting

the aforementioned drawback.

  For this purpose, the invention proposes a support of the type com-

  taking compounds having photochromics for

  to turf the radiation reflected by the support during the photocopying operation; according to the invention, the photochromes are

  incorporated in an individualized way to the support.

  Individual incorporation is understood to mean that the photochrome is integrated into the support in a manner which prevents the interactions mentioned above: it may be in particular a - integration by polymeric layer, by microcapsules, by microbeads, by insoluble micro-fuel. , or any combination of

these means.

  Naturally, it is possible to associate several photochromics, and to combine them, if necessary, with a dye or

a pigment.

  According to a particularly advantageous characteristic of the invention, the photochromic (s) are associated with at least one photosensitizer. Indeed, some photochromes are not

  sensitive to certain wavelengths that are not

  delivered by the photocopiers: in this case, they do not react. Also, by associating them with photosensitizers, well chosen, it is possible to obtain the photostaining of

  photochromic even under the ordinary radiation of photocopiers.

  The support may be paper-type or consist of a polymer film. Particularly within the scope of the invention is a support consisting of a transparent or translucent film, one side of which is made self-adhesive, and which is applied against a background

  papermaker (or other) himself having graphic information.

  Other benefits and features will emerge from the

  detailed description which will follow, as well as examples of

  production. As recalled at the beginning of this memoir, it is generally possible, thanks to special colored papers, to prevent photocopying by means of a copying machine, for example of the xerographic type. The process has been the subject of long development;

  let's quickly recall the basic ideas.

  Most normal paper copying machines use: on the one hand, a light irradiation system (lamp, flash tube, ...) that has its own emission characteristics in wavelengths, which do not interact not all of them

  same way with the original document.

  on the other hand, a receiver system of the image of the original, which does not react uniformly with all wavelengths

the emission spectrum of the lamps.

  It will follow that during the transfer of the receiver to the support, there will be a more or less good reproduction of

2 6 18812

  wavelengths absorbed (color) and therefore those

  reflected by the original document.

  In the case of xerographic-type copying machines, the receiver varies according to the apparatus: selenium, zinc oxide,

  cadmium sulphide or organic materials (polyvinyl carbazole).

  Their reaction to the wavelengths reflected by the original document is not quite the same. Some types of machines easily photocopy blue and red but have

  difficulties with the yellows. Other types of photocomputers

  well yellow, but have difficulties with the blues.

  With regard to the single-color photocopy in black, it can be seen immediately that, depending on the case, the yellows or blues will not give an impression on the photocopy; only reds are not a problem. For color photocopying, taking into account the principle of trichromia (or tetrachromy), these phenomena have been taken into account and technical compensation has been used.

  In the following it will be reasoned on the mono photocopy

  color (for example black) and specify when it will be necessary

  re, the case of the photocopy of colors.

  Thus, if one wants to disturb, or even prevent, the photocopy of original documents, it is advantageous to take a red-dominant background, so that it appears black on the photocopy, minimizing or canceling any contrast with the original. graphic information usually in black or dark blue. It is therefore proposed to use an original document medium colored with a mixture of blue, yellow and red (or a little black), but so that the visual contrast between the colored background and the Graphic printing is good and allows readability

correct.

  The use of photochromic will improve this contrast, even to the limit to avoid having a sustained color support. In other words, it is possible to use, for example, a special white or pastel paper containing, of course,

photochromic.

  Photochromism has been known for a long time and consists of a reversible photostaining that can be schematized as the transition from a state A to a state B under the effect of active electromagnetic radiation with return of the state B to the state A in

the absence of said radiation.

  State A has spectral characteristics that condition

  on the one hand, its color, on the other hand its reactivity in the photochromic mechanism. So A can be colorless absorbent in

  ultraviolet light and active wavelengths for its photocolora-

  are precisely in the ultraviolet range.

  State B has spectral characteristics different from A which condition its color. So B can be colored so

will absorb in the visible.

  Thus, during irradiation by the photocopier, it will be possible to reveal colorations. If the photochromes are well chosen with respect to the spectral characteristics of the photocopiers, it will be possible to have a color effect such that the photocopy appears in black. If necessary, the combination of this color with that of the support

will enhance the effect.

  All the photochromic substances can in principle be used according to the invention, whether they are in the solid state or can be used in solution. By solution is meant a solid or liquid solution. So any substance incorporated in

  a polymer assembly is considered as a solution.

  The following photochromes can be mentioned in a non-exhaustive manner: Silver salts, metal oxides, mineral complexes, mineral glasses, nitrones, cationic polymethine dyes,

  tetrachloroceto dihydronaphthalene, sydnones, indigoides, spirodihy-

  droindolizines, indenones oxide, fulgides, dianthrones, azobenzenes, triphenylmethane derivatives, metal derivatives of

dithizones, spiropyrans.

  These photochromes should preferably have a good ability to photostain (photocolorability) by the radiation emitted by the photocopiers. However, this one is most often located

  at wavelengths greater than about 360 nm.

  It turns out that many photochromics react poorly to these wavelengths, so have poor photocolourability. It is possible to give them good photocolourability by using sensitive photosensitizers above 360 nm which

  will transfer the energy they have absorbed into the photo-

  chrome to activate them (color). The rules of photochemistry indicate how to adapt the photosensitizer to the

substance (photochrome) to activate.

  All known photosensitizers can be used. However, mention may be made, for organic substances, of the following products: benzene, acetone, xanthone, acetophenone, benzophenone, triphenylene, anthraquinone, Mischler's ketone, naphthalene, chrysene, diacetyl, benzil, pyrene,

anthracene, perylene ...

  However, to be active, these photosensitizers must be in a much higher concentration than the photochromic one. They must be intimately related to photochromics under specific environmental conditions, which leads to the use of

  special implementation technique detailed below.

  The photochromics can be used as they are, when they are solid, and can be dispersed in the macromolecular support of the original document. Unfortunately, very often and this is the case of some photochromic sensitized, it will require an auxiliary medium. Indeed, the photochromic or sensitizer can react with the macromolecular medium support of the original document. This is the case for example for. spiropyrans that interact with cellulose or paper additives to give irreversible staining due to a merocyanine dye. It is therefore necessary in general to avoid interactions by putting the photochrome and its additives in or on a medium that will be individualized compared to the rest of the support

  macromolecular of the original document.

  Several solutions are possible: 1 / Dissolution of the photochrome, photosensitizer (s) and stabilizing additives in a plasticized polymer. The assembly may be deposited: a) on the macromolecular support either in the form of a film or with the aid of a solution in an evaporable common solvent,

b) in the mixing medium.

  2 / Formation of plastic microbeads containing the photochrome, the photosensitizer (s), the additives, the polymer (s) and plasticizers. The assembly can be obtained by conventional methods for forming the polymer microbeads: a) by incorporation before polymerization of the monomer (s), b) by diffusion in already prefabricated microbeads using an evaporable intermediate solvent good photochromic solvent and other additives, but only swelling of the polymer; the solvent is of course evaporated at the end of preparation. These microbeads can then be incorporated into the macromolecular material

  basic support of the original document.

  3 / Manufacture of photochromic microcapsules.

  The preparation of the microcapsules is known and the

  Well-mastered manufacturing methods are all conceivable.

  In general, the photochromic (s), the photosensitizer (s), the additives, the polymer (s), the plasticizers are dissolved in a common high-boiling solvent. The solution thus obtained is dispersed with violent stirring in an immiscible secondary solvent (water for example) in the presence or absence of a surfactant thus forming an emulsion or a microemulsion, and chemical agents are added which will be formed by reaction with the interface, an insoluble macromolecular film around the microdroplets forming the emulsion. The microcapsules thus obtained are separated by

  physical means, secondary solvent and optionally dried.

  The microcapsules can then be incorporated in or on the base material of the support of the original document. The advantage of

  microcapsules is on the one hand, the individualization of the photo-

  chromic complex containing this time a solvent that plays an active role in the photochromic mechanism, and secondly, a better control of the parameters involved in the

  photochromism such as concentration of products.

  os05 4 / Deposit on or in a non-soluble micromilieu.

  There exist micromilieux in the form of powder consisting of solid microparticles or of inorganic origin (silica microbeads, zeolite, molecular sieve, etc.) or of organic origin, for example based on crosslinked polymers (styrene-divinylbenzene copolymer). ). These micromilieux have either cavities (pores) that can store chemicals or adsorption properties that retain chemicals by physicochemical interaction. We

  can therefore deposit mixtures consisting of photochromic, photo-

  sensitizers, additives, polymers on or in these micromilieux.

  The photochromic assembly can then be incorporated in or on

  the base material of the support of the original document.

  It is now possible to specify the anticopy method according to the invention. It consists in manufacturing a special macromolecular support which will be used for the preparation of the original document by printing the graphic information by the usual means: typing, offset printing, typographic printing, laser printing, inkjet, photocopy, manual graphics. .. This support is manufactured by putting into play the principles that we have already exposed in detail, it being understood that the coloration of the original document can be abandoned if it turns out that the photochromic used completely cover the range

  spectral, rendering the photocopy unreadable.

  It should be noted that the mixing of the individualization systems is possible as well as the use of several photochromics of different chemical structure, and that it is possible to incorporate

  dyes in the individualization system if necessary.

  The proposed method proves to be particularly effective with regard to monocolour photocopying (black) ... In the case of color photocopying (tri- or tetrachromy) it leads to a strong alteration of the colors rendering the photocopy non-compliant. 'original. The special support can have various shapes but in most cases it is flat which facilitates its use. This will be in most cases either transparent, translucent or opaque plastic films or sheets

of paper.

  The special support which is the subject of the invention is therefore formed of dyes, possibly photochromes, but especially of a bottom support. This bottom support will be: - either a plastic film manufactured according to the usual techniques; among the polymers that can be used, mention may be made, for example, of cellulose and its derivatives, polyvinyl chloride, polyolefins, polyolefin-polyacetate copolymers,

  vinyl, polyesters, polyvinyl acetates, poly-

  carbonates, hydrochlorinated rubbers, ...

  - or papers with fibrous structure: papers based on natural fibers (such as cellulose), papers based on synthetic fibers (such as regenerated cellulose or polypropylene) These papers usually contain after manufacture

additives and fillers.

  The special support is manufactured by the conventional means specific to each type of material. The dyes and the individualized photochromic systems can be either incorporated in the mass or deposited on the surface, for example by coating or coating. The dyes used must be compatible with the polymeric material of the base support. At the limit, for opaque substrates, pigments are used. For ordinary paper based on cellulose fibers, it is possible, for example, to use the following basic colors: - blue - yellow - red - brown and black for example manufactured by

  the BAYER, BASF, SANDOZ, CIBA Companies.

  It is obvious that one can also obtain a paper

  of color using pure or mixed pigments.

  The desired intense or clear coloration depends on the relative proportions of the various basic dyes, proportions that depend on the nature of the photochromic used. As he has

  already been said, we can also not put dye.

  The manufacture of microcapsules, the principle of which has already been presented, requires a solvent with a high boiling point, of which the vapor pressure is low, the specific gravity is close to one, absorption in the ultraviolet and the visible low (X max <320 nm), good solvent photoschromes - photosensitizers - additives - polymers, immiscible in polar solvents such as water, alcohols, ... Include but not limited to: aromatic derivatives hydrogenated or not (eg terphenyl hydrogen, cymene, tetralin, decalin, ...), esters which are sometimes used as plasticizers for plastics (for example dioctyl phthalate, butyl laurate, butyl stearate, etc.), ethers (for example, diglyme, diethylene glycol

dibutyl ether, ...).

  A solution of the photochromic (s), photo (s)

  sensitizer (s), additives, polymers and possibly

  surfactants, is then done by heating if necessary.

  Note that by additives, we mean all products necessary for the proper operation of photochromes, as has been shown in the technical literature and the stability of other products used (antioxidants, ...). The use of polymers is interesting because it increases the viscosity of the photochromic solution and allows the development of its photochemical properties. Among the polymers (or copolymers) that may be used, mention may be made of: polystyrene, polyvinyl chloride, polymethyl methacrylate, polyacrylate, polyurethanes, polyimides, polyoxyethylene glycols, polyvinyl acetals, gelatin, gums. The concentrations of the different products vary according to their nature and the desired effect,

  it is difficult to specify the limits.

  Microcapsules can be prepared using, for example, the following two procedures: 1 / In 180 g of 11% gelatin in aqueous solution at 55 ° C., 40 ml of photochromic solution are also incorporated with violent stirring at 55 ° C. In the emulsion thus formed, 180 g of 11% aqueous gum arabic are added at a pH of 9 and 630 g of water, all at

  also.

  Still stirring, the mixture is cooled rapidly to 10 ° C. in the presence of 10 ml of 25% aqueous solution of glutaraldehyde. After one hour, 15 ml of a solution of polymethylvinyl ether maleic anhydride copolymer are added and the mixture is stirred for one hour before adding 5 ml of a 20% solution of sodium carbonate and the necessary amount.

  10% aqueous sodium hydroxide to bring the pH to 10.

  The dispersion obtained is then ready to be used.

  2 / A mixture A consists of: g of urea-formaldehyde precondensate containing 45% of active resin and 35%

solid content.

  g of melamine-formaldehyde precondensate containing about 76% of resin

  active and at 71% solids content.

  240 g of 20% aqueous solution of acrylamide and acid copolymer

acrylic (40%).

850g of distilled water.

  800g of this mixture A is added 200g of water and then with rapid stirring is incorporated 800g of photochromic solution. The remainder of the mixture A and 1400 g of distilled water are then added as diluent. Stir 30 minutes then adjust the pH to 4.7 with acetic acid. Stirring is continued for 30 minutes. The whole is brought to a water bath at 55 ° C. and stirred for 2 hours at this temperature. It is allowed to cool slowly for 5 to 6 hours. The pH is then adjusted to 10.0. A solution of microcapsules is obtained

ready to use.

  The preparation of the micromilieu is made from photochromic solid particles. These particles are obtained by mixing solid microparticles (3 to 5 μm) with a photochromic solution as described above. The assembly thus formed must have a fluid appearance, each microparticle being

  individualized. They can then be coated in the following manner.

  These photochromic microparticles are dispersed in a suspension of polyvinyl alcohol (of water-soluble film-forming quality) in water in the presence of a surfactant. This mixture is stirred in a paddle mixer for about one hour. A check under

  microscope is performed to ensure the quality of the coating.

  The suspension can be used as it is or filtered and dried with stirring. The following proportions can be given for this preparation: photochromic microparticles 10 to 30 parts polyvinyl alcohol 1 to 5 "surfactant O to 0.1" water 60 to 90 n

  Other coating modes can be used.

  Photopolymeric microbeads can be prepared

  chromic in the following manner. To a photochromic solution containing, inter alia, a plasticizer, microbeads are added either in the dry state or in the form of an aqueous suspension and the mixture is stirred more or less slowly. This stirring and the stirring time depend on the polymer material and its

  starting state. The swelling state is monitored under a microscope.

  Increasing the diameter of the microbeads by swelling should not exceed 1.5 to 2 times the initial average diameter. As soon as it is estimated that the swelling is sufficient, the mixture is filtered off and the swelling solvent is removed by stirring the assembly at room temperature. An alternative is to atomize the assembly in a vertical tube with warm air and recover the photochromic microbeads in a cyclone separator. Any other drying method can be used. After removal of the swelling solvent, the photochromic microbeads must contain between 10% and 10% plasticizer. The photochromic microbeads thus prepared will then be incorporated for example into a solution

aqueous coating.

  The original documents obtained from the copy-copying media develop during photocopying a fugitive auxiliary coloration. This coloration is due to photochromes and has a lifetime that is variable depending on the material of the compounds used. The original documents thus return to their appearance

primary after photocopy.

  Some examples are given below of the special supports for making non-photocopiable original documents

according to the invention.

  In general, the photocopies were made on three types of machines xerographic type in one color (black), which respectively show an irradiation: - by flash lamp - halogen tungsten lamp

- by fluorescent tube.

  The analysis of photocopies obtained by photocopying machines in one color (eg black and white) is done by measuring the contrast between the surface corresponding to the background (support) of the original document and the graphic printing. This measurement is done in two ways: 1 / visually on an original document including a text. In

  in this case, the illegibility of the photocopy is noted.

  2 / technically on an original document including a simple black band. In this case, using a reflectometer or a microdensitometer, the differences in reflection or

  absorption of the two formed zones.

  In the case of color photocopying, the test is

only visual.

EXAMPLE 1

  A copy-copying paper comprising a coloration and photochromic microcapsules is manufactured in the following manner: the paper used is based on cellulose with conventional fillers; the coloring of the paper is obtained using a mixture of red (pantone) warm red) 8 parts, yellow (pantone yellow) 8

  black parts (pantone black), 0.25 part.

  This mixture of dyes is deposited on the paper by

  coating at the concentration of 1.5g of dry dyes per m2.

  - the photochromic microcapsules are made from

  hydrogenated terphenyl in which trimethyl

  1 ', 1', 3 'indolino - 2' - spiro - 2 - nitro - 7 - naphtho (2,1 - b), pyran at the concentration of 4 l102 mol, 1,2 - dihydroxy anthraquinone at a concentration of 2.10. -1 Mole using the procedure

n l presented above.

  These microcapsules are deposited by coating with a binder (starch, polyvinyl alcohol, etc.) in a thickness of

  micrometers about 10g per m2 of paper.

  After printing a black text on this copy and copy paper on the 3 types of common photocopying machine, in one color (black), the photocopies obtained are

  illegible and have only a uniform black background.

  Contrast measurement on a photocopy using a reflectometer does not show a difference between the background and

graphic printing.

  The original brown document is perfectly legible.

  After irradiation by the photocopiers, the document

  original resumes its original coloring in about 10 seconds.

  A photocopy using an electrostatic-type color photocopier shows a dominant of blue compared to

original document.

EXAMPLE 2

  A copy-copying paper comprising coloring and photochromic microcapsules is manufactured as follows:

  - The paper used is cellulose based with fillers -

conventional.

  - The color of the paper is obtained using a mixture of red (pantone warm red) 12 parts, yellow (pantone yellow) 4 parts. This mixture of dyes is deposited on the paper using a Meyer bar at the concentration of 1.5g of dry dyes

by m.

  the microcapsules are manufactured from terphenylhydrogen in which there has been dissolved trimethyl-1,3 ', 3' indolino-2'-spiro-2-dibromo-6,8-benzo (b) pyran at a concentration of 5 × 10 -3 Moles, of 4-aminoacetophenone at a concentration of 2.10-2 Mole and 3% of average molecular weight polystyrene using the

  Operative No. 2 presented above.

  The microcapsules are deposited by coating with a binder to a thickness of about 10 microns or 10

m2 of paper.

  After printing a black text on this copy and copy paper (in black), the photocopies obtained are unreadable and have only a uniform black background. Contrast measurement on a photocopy using a reflectometer does not show

  no difference between background and graphic printing.

  The original dark orange document is perfectly

  readable. After irradiation, it fades in 2 seconds.

EXAMPLE 3

  A copy-copying paper comprising coloring and photochromic microcapsules is manufactured as follows:

  The paper used is of conventional type.

  The color of the paper is obtained using a mixture of yellow (pantone yellow) 4 parts, red (pantone warm red) 12

  parts and black (pantone black) 0.25 part.

  This mixture of dyes is deposited on the paper at

  concentration of 1.5g dry dyes per m.

  The photochromic microcapsules are prepared from decalin in which 6-methylthio-3-methyl-2-benzothiazolino-2-spiro-3-spiro-3-methyl-8-methoxy-6-nitro-benzo (b) pyran has been dissolved at a concentration of 4.102. Mole, phenyl - 4 acetophenone at the concentration of 10-1 Mole and 5% polystyrene using the procedure n l. These microcapsules are deposited by coating with a binder in a thickness of about 10

  micrometers is 10og per m2 of paper.

  After printing graphic information, the original brown document is perfectly legible. After photocopying with black-colored electrostatic type copying machines, the photocopies obtained are illegible and have only a background

continuous (black).

  The original document after irradiation by

  photocopiers resumes its original hue in 5 seconds.

EXAMPLE 4

  A copy-copying paper comprising a color and

  microcapsules is manufactured in the following manner.

  The paper used is of conventional type (cellulose).

  The color of the paper is obtained using a mixture of red (pantone warm red) 10 parts, yellow (pantone yellow) 5

  parts and black (pantone black) 0,25g part.

  This dye mixture is incorporated into microcapsules using conventional techniques and hydrogenated terphenyl as the solvent. These colored microcapsules are incorporated into the paper by coating with a binder (alcohol

polyvinyl) - sample 1.

  The photochromic microcapsules are prepared from tetralin as a solvent in which trimethyl 1 ', 1', 3 'indolino - 2' spiro - 2 - nitro - naphtho (2,1 - b) pyran has been dissolved at a concentration of 3.10. - 2 Moles, 4-phenylacetophenone 10-1 Mole and 8% polystyrene (low molecular weight) using technique n 2. The photochromic microcapsules are deposited by coating with a binder (polyvinyl alcohol) on the sample 1 in a thickness of about 10 microns or 10g

about per m2 of paper.

  After printing graphic information, the original brown document is perfectly legible: photocopies obtained using black monocolour photocopiers are illegible. The measurement of the contrast on these photocopies by reflectometry does not

  shows no difference of reflection.

EXAMPLE 5

  A copy-copying paper comprising a coloration and photochromic microcapsules is prepared as follows:

  The paper used is cellulose based.

  The color of the paper is obtained using a mixture of red (pantone warm red) 8 parts, yellow (pantone yellow) 7

  parts and black (pantone black) 0.5 part.

  This dye mixture is incorporated by coating to the

  concentration of about 1.59 dry dyes per m2.

  The photochromic microcapsules are made from hydrogenated terphenyl in which the trimethyl - 1 ', 1', 3 'indolino - 2' spiro - 2 - nitro - 7 - naphtho (2,1 - b) pyran is dissolved at a concentration of 4, 10-2 Mole, 4 - phenylacetophenone and 1,2 - dihydroxyanthraquinone at the concentration of 10-2 Mole and 3% of polymethylmethacrylate respectively.

using the procedure n l.

  The microcapsules are deposited by coating on the paper with starch to a thickness of about 10 micrometers

about 10g per m.

  The antipopy medium obtained is brown. After

* printing a black text the document is perfectly legible.

  Photocopies obtained on electrostatic copying machines

  are uniformly black and unreadable.

EXAMPLE 6

  A copy-copying paper comprising a coloration and photochromic microcapsules is prepared as follows:

The paper is cellulose based.

  The color is obtained using a mixture of red dye (pantone warm red) 2 parts, yellow (pantone

yellow) 12 parts.

  This dye mixture is incorporated into the paper by coating with a binder and at a concentration of 1.5 g of

dry dyes per m2.

  The photochromic microcapsules are of two types: first prepared as indicated in Example 1, and secondly,

  prepared as in Example 3.

  An equal mixture of these two types of capsules is deposited by coating with a binder (polyvinyl alcohol on

  the support at a thickness of 10 microns is 10g per m2.

  The support obtained is light orange in color and the original documents obtained after printing a graphic information are perfectly legible. The black single-color photocopies obtained from this original document are uniformly

black and illegible.

EXAMPLE 7

  An anticopy paper is prepared by the same method as

  Example 6 but without using staining.

  The results are in all respects comparable to those of

example 6.

EXAMPLE 8

  A paper comprising only photochromic microcapsules is manufactured as follows:

  The paper used is cellulose based.

  The photochromic microcapsules are prepared from

  hydrogenated terphenyl, mercuric dithizonate

  4 102 Mole, 4-hydroxybenzophenone at the concentration

10-1 Mole.

  The microcapsules are deposited by coating on the paper using a binder (polyvinyl alcohol) in a thickness

10 micrometers is o10g per m.

  The resulting paper is orange. After printing a black text on this paper, a photocopy on a black solid electrostatic copying machine is illegible

  presenting a uniformly black surface.

  The original document after irradiation becomes discolored in 15

about seconds.

EXAMPLE 9

  A copy-copying paper comprising only a photochromic micromilieu is prepared in the following manner: The paper used is cellulose-based and has been subjected to

  pretreatment with polyvinyl alcohol.

  The photochromic micromilieu is prepared from: on the one hand 10-3000.10-10m microporous CPG (Controled Pore Glass) with an average particle size of 10 micrometers, and on the other hand with a solution of tri (N, N-dimethylamino-4-phenyl) -1) ethane nitrile at a concentration of 3.10-3 mol, cyanide of

  potassium at a concentration of 10-2 Mole, carbondetrabromide

  at a concentration of 10-2 mol, in solution in poly-

  oxyethylene glycol 700 at 1% water.

  The solution is incorporated in the micromilieu at the

  concentration of 0.5 milliliter for g19 micromilieu.

  In order to avoid any exudate, this system is coated with a layer of polyvinyl alcohol using the technique described above. The whole polyvinyl alcohol and micromilieu is used as such to prepare by coating on paper the

support of the original document.

  The copy paper thus obtained is almost colorless.

  After printing a graphic information on this medium, the photocopies obtained using black electrostatic machine electrostatic black uniform appearance unreadable. The document

  original regains its original color after 2 minutes.

EXAMPLE 10

  A copy paper is prepared according to Example 4 but using synthetic paper instead of cellulosic paper. This paper is based on polyethylene fibers related

with polyvinyl alcohol.

  The results are in all respects comparable to those of

example 4.

EXAMPLE 11

  A transparent plastic film anticopy is prepared according to Example 4 but instead of using cellulose-based paper a transparent plastic sheet acetate

cellulose 0.1 mm thick.

  The results are in all respects comparable to those of

example 4.

EXAMPLE 12

  A copy-copying paper comprising a photochromic macromolecular staining and coating is manufactured as follows

The paper is cellulose based.

  The color of the paper is obtained using the following mixture: red (pantone warm red) 8 parts, yellow (pantone

  yellow) 8 parts and black (pantone black) 0.25 part.

  This dye mixture is incorporated into the paper by coating with a binder at a concentration of 1.5 g of

dry dyes per m2.

  Auxiliary treatment is made with the coated paper with polyvinyl alcohol to avoid any reaction of the cellulosic fiber. The coating is made with a solution of 1,1,3-trimethylindolino-2'-spiro-2-nitro-7-naphtho (2,1-b) pyran at a concentration of 4.10-3 mol of 4-phenylacetophenone at a concentration of 2.10-2 mol of 20% polyvinyl butyral, 1% of butyl laurate as plasticizer in a 50/50 mixture of acetate

  of ethyl and toluene as a solvent.

  The viscous macromolecular photochromic solution is

  spread using a Meyer bar on the paper.

  After evaporation of the solvent, a brown support is obtained. After printing a graphic information, the original document is photocopied in black. Photocopies obtained

  are uniformly black so illegible.

EXAMPLE 13

  A copy-copying paper comprising a coloration and a photochromic micromile is prepared as follows:

The paper is cellulose based.

  The coloration and its incorporation into the paper are the

same as for example 1.

  The photochromic micromilieu is obtained from CPG

  (Controled Pore Glass) 10 - 3000 microporous 10o-m granulometry

  average size 10 micrometers. A photochromic solution in the decalin of trimethyl 1 ', 1', 3 'indolino -2' spiro-2-nitro-7-naphtho (2,1-b) pyran at the concentration of 4.10 -2 Mole, 4-phenyl acetophenone at the concentration of 2.10-1 Mole is incorporated in the micromilieu at the concentration of 0.5 milliliter

for lgr. of micromilieu.

  In order to avoid any possibility of exudate of this system, it is coated with a layer of polyvinyl alcohol using the technique described above. In this case the medium is used directly without drying. This preparation is then deposited on the colored paper by coating to a thickness of 10 micrometers

about 109 per m2.

  The copy paper thus obtained is brown.

  - After printing a black text on this medium, the

  photocopies obtained using the electronic copying machines

  Static black monocolores have an unreadable black uniform appearance.

EXAMPLE 14

  A copy-copying paper comprising a color and photochromic microbeads is manufactured as follows:

The paper is of the cellulosic type.

  Staining and incorporation into paper are

identical to those of Example 1.

  The microbeads are based on polystyrene. They were obtained by emulsion polymerization and have a diameter of about 5 microns. They are rendered photochromic by

  swelling in a photochromic solution.

  The photochromic solution is made from cyclohexane as solvent in which trimethyl -1 ', 1', 3 'indolino-2'-spiro-2-nitro-naphtho (2,1-b) pyran was dissolved at the concentration of 10-2 Mole, phenyl - 4 acetophenone at a concentration of 5.10-2 Mole and a plasticizer: laurate

butyl 8% by weight.

  The microbeads are swollen at 20 ° C. in the solution with slow stirring. The magnification of the beads is monitored microscopically to a diameter of 8 micrometers. After cooling, the swollen microbeads are filtered and

let it dry.

  The microbeads are deposited on the paper by sleeping

26 1-88 12

  using a binder (polyvinyl alcohol) in a thickness of 15

  micrometers or about 109g per m2.

  The support obtained is brown. After printing a black text on this anti-copying medium, the original document is perfectly legible. Photocopies obtained with black monostatic electrostatic copying machines are

uniformly black and unreadable.

  The use of paper-based media as indicated can protect genuine documents against fraudulent copying using copy machines. It is possible to indicate in a non-exhaustive way the original documents which are presented

  in the form of books, journals, reports, letters, ...

  The user of this type of non-photocopiable paper whether white or colored must however know that a number of precautions for use are to be respected. They concern first the inks. The inks, black, red, dark blue, dark purple, do not pose any problems of use for the graphic printing. Any clear, white or yellow inks are to be avoided because coming superimposed on the paper, they will prevent the anticopy effect. For example, on a xerographic photocopier, a white ink on a copy-copying paper gives a black-and-white photocopy with the graphic print in white so legible. Similarly, it will be necessary for use to avoid corrections that alter the properties of the non-photocopiable paper medium. Especially the scrub, the use of correcting fluid (white) for typos, bleaches for ink, any chemical, varnishes, ... are

to avoid.

  In order to overcome the problem of corrections, it is

  possible to make sticky or self-adhesive non-photocopiable

  tights. The user will be able to stick to the place where the graphic is incorrect a strip of non-photocopiable paper and can correct its graphics without disturbing all

properties of the support.

  The preparation of non-photocopiable adhesive paper may

  to be done by conventional methods.

EXAMPLE 15

  On a paper backing paper 60g / m2, is deposited by traditional coating a pregelatinized starch in 10% aqueous solution in order to deposit a film of adhesive (3g of dry glue per m2). After drying, the sticky backing paper formed can be used after wetting to be bonded to eg a paper surface. This copy-copying paper works like those

we saw previously.

  Preparation of self-adhesive non-photocopiable paper

  can be done by the usual methods.

EXAMPLE 16

  On a 60g plain paper, a silicone coating is applied by spraying in order to avoid any adhesion. On the silicone coating is sprayed an acrylic emulsion (polyacrylate methyl and polyacrylic acid) to 50% dry solids in one layer

  homogeneous then apply photochromic paper anticopy.

  The adhesive is thus transferred to the copy-proof paper and an anti-copy sticker paper is obtained. It is possible to use the anti-copying papers such as those presented previously. These anti-copying papers are used like all

self-adhesive systems.

  These non-photocopiable sticky or self-adhesive papers can also be used to make partially non-photocopiable originals. For example, if you do not want a part of a graphic print: words, names, figures, signatures, details of drawings, ... be photocopied, just paste a piece of paper in the space provided. photocopiable and continue the graphics. On the photocopy using an electrostatic photocopier the non-photocopiable part will appear in black while the rest of the document

original will be readable.

  It is appropriate at this level to specify the problems posed by the photocopy in connection with non-photocopiable media of the invention. These supports are particularly effective vis-à-vis electrostatic photocopiers type or

  Xerographic. These are by far the most common.

  The case of electrostatic single-color photocopiers (the

  more often in black) has been described at length.

  The color in a single-color system is given by the "toner" after printing the image receiving system. So in one-color photocopy, regardless of the color of the "toner" black, red, blue, yellow ..., the photocopy obtained with the anti-copying papers of the invention will be uniformly colored and therefore unreadable. With regard to "color" copiers, they operate by electrostatic processes with 3 or 4 colors, excluding other color reproduction systems, among others, argentic or non-silver photography. The color photocopies obtained using the copying papers of the invention are clearly disturbed since the reproduction of the

  colors no longer conform to the original.

  The use of colorless or colored photochromic films can be multiple. First of all, original document films having a graphic impression. These films behave like non-photocopiable papers and all that has

  been said for papers is applicable in this case too.

  These non-photocopiable photochromic films can be used to protect documents obtained using conventional cellulose-based or synthetic-based papers, films and with graphic printing. It suffices to cover said documents with a non-photocopiable photochromic film. These are the filming or laminating processes. All laminating or plasticizing processes can be used: gluing, hot pressing, self-adhesive. The filming or lamination may cover all or part of the document to be protected on one or both sides of the

document.

  It is thus possible to produce original non-photocopiable documents.

EXAMPLE 17

  A transparent-anticopy film is prepared according to Example 11, taking care to locate the uncoated side. The document to be film-coated is covered by the transparent film, taking care to put the uncoated side on the document and the whole is pressed hot between 60 and 80 C. The original document thus obtained gives results in all respects comparable to those of example 11. Photocopies obtained with photocopiers

  black monocolors are uniformly black and unreadable.

EXAMPLE 18

  A sticker anti-copying film is prepared from the same

  way as for Example 16 and a self-adhesive film is obtained.

  However, it is possible with respect to the adhesive to substitute for the acrylic emulsion a solution of styrene-butadiene rubber in a mixture of ethyl acetate-acetone-toluene solvents. The document thus obtained can be used to laminate all documents, particularly those based on paper. The original non-photocopiable laminated documents thus obtained have exactly the same properties as the original anti-copying documents presented in the preceding examples. It can be noted that all original documents prepared with photochromes show a slight increase in color when exposed to intense light irradiation such as sun, high-power lamp (especially

  halogen), illumination with multiple fluorescent tubes.

  Thus an original document white or clear, if it is exposed to the light of day takes clear hues, which does not interfere with the reading of the document. For original color documents, the

  hue change is barely noticeable.

  It is therefore interesting for these original documents to treat, read and manipulate them under conditions of illumination.

moderate, about 50 lux.

Claims (9)

  1. A printing-writing medium intended to make any photocopy that is not in conformity with the original or illegible, of the type comprising compounds comprising at least one photochromic intended to disturb the radiation reflected by the support during the photocopying operation, characterized in that the photochromic is incorporated so individualized to the support.   2. Support according to claim 1, characterized in that   it further comprises at least one dye.   3. Support according to any one of claims 1 or   2, characterized in that it further comprises at least one   photosensitizer associated with the photochrome.   4. Support according to any one of claims I to 3,   characterized in that the photochrome is incorporated according to at least one of the following forms: polymeric layer, microcapsules, microbeads, micromilieu insoluble.   5. Support according to any one of claims 1 to 4,   characterized in that it is a paper-type support.   6. Support according to any one of claims 1 to 4,   characterized in that it is a polymeric film.   7. Support according to claim 6, characterized in that   it has a self-adhesive side.   8. Support according to any one of claims 6 or   7, characterized in that the polymer film is associated with a bottom stationer.   9. Anti-copying process, characterized in that it consists in printing or writing on a support according to any one of Claims I to 8.