FR2483480A1 - SECURITY PAPER THAT CAN BE USED TO AVOID FALSIFICATIONS WHICH MAY RESULT FROM THE USE OF ERASABLE INK PENS - Google Patents

Abstract

THE PRESENT INVENTION RELATES TO A SECURITY PAPER THAT CAN BE USED TO FIGHT AGAINST FALSIFICATIONS THAT MAY OCCUR FROM THE USE OF AN ERASABLE INK, CHARACTERIZED IN THAT IT INCLUDES ON THE SURFACE, MICROCAPSULES CONTAINING A SOLVENT OF THE SAID INK.

Description

The present invention relates to a new

  security paper usable to avoid forgery-

  tions in. case of using an erasable ink pen Recently a new erasable ink ballpoint pen was described, notably in the patent

US 4,097,290.

  The particularity of this pen lies in the original composition of its ink specially developed to be able to be erased by conventional mechanical means and more particularly by erasing. This new type of easily erasable writing medium represents a definite advantage for current use, but constitutes a danger when it is used to fill in security documents, check payment vouchers or other, all parts generally susceptible

to be falsified.

  It is therefore useful to have a paper, usable especially for payment vouchers which prevents the possibility of falsification when using

  a new pen as described above.

  French patent 2,280,154 has already proposed a protection and detection method which

  is to use a support covered with a layer.

  The support and the layer having different properties

  spectral reflection rents in the visible, ultraviolet or infra-red domains, any alteration of the layer by scraping or erasing will be detected by an appropriate device. This solution is valid for combating the erasure of writing means which are difficult to erase

  such as conventional ballpoint pens, pencils -

  felts., etc ... but not for the means of easy writing

  such as erasable ballpoint pens.

  It was found and that is the purpose of the

  present invention which can be prevented bcute falsi-

  fication of a paper, written using a ballpoint pen as described above, by disposing on the surface of the paper of microcapsules torn during writing

and which contain a solvent.

  The present invention therefore relates to a security paper characterized in that it comprises on the surface

  -: solvent microcapsules of an erasable ink.

  MicrocaDsules containing various fluids have been described and used in many

  technical areas. In the present invention,

  use any of the known methods for making these capsules; it will be enough to make sure, and the technicians will make the necessary tests to be sure that with the erasable ink pens used the tip (or the nib) of said pen tears effectively

  said microcapsules during writing.

  These microcapsules may be dispersed in the bulk of the paper or be concentrated in the surface layer of this paper. The latter technique is much preferable because it reduces the amounts of microcapsules to be used. When the

  microcapsules are concentrated in the surface layer-

  the (coating layer) this layer must contain from to 70% by weight, relative to the weight of the dry coating layer, of microcapsules. An insufficient quantity of capsules would not allow sufficient modification of the penetration of the ink into the paper; too large a quantity of capsules would not allow the production of a coating layer having

  sufficient mechanical properties.

  The solvents usable inside the microcapsules are all the solvents which, in contact with the ink deposited by the pen on the paper, increases

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  the speed of diffusion of the ink inside the paper. For example, solvents of aromatic or aliphatic nature or products

  chlorinated ... These solvents may contain a plastic

  trusting t1l as dioctylphthalate for example.

  The coating layer containing the microcaps-

  sules will have, in addition to these capsules, a known composition based on filler binder. It may however be desirable to protect the capsules and to allow a better distribution of these capsules in the layer; to add to the known constituents of the coating layers, a microcapsule spacer. This microcapsule spacer is a product in the form of solid grains (calibrated starch, cellulose powder, etc.) which is mixed with the ingredients forming the coating layer and which disperses between the microcapsules in the finished layer. It is possible to use from 3 to 20% by weight, relative to the weight of

  the sleeping layer, of this distance.

  As indicated above, the other ingredients of the coating layer are known products, in particular a binder, for example starch, PVA, latex, which may be used in an amount of approximately 5 to 20% by weight relative to the weight of the layer, a filler for example kaolin, carbonate which can be used at a rate of approximately 15 to 45% by weight relative to the weight of the layer and the various additives known and used for the

  creation of sleeping layers. -.

  Obviously the papers according to the invention may further comprise, in their mass and in their coating layer, the known elements which are used

  or usable to fight against falsifications.

  The method of making the invention uses

  any papermaking process that allows incorporation, -

  tion in paper but preferably in layers

  for coating the microcaosules containing the solvent.

  The following non-limiting examples

  illustrate the invention; in these examples the percent-

  tages and the quantities of material given in the examples are expressed in dry matter with respect to

to dry matter.

Example 1

  On a mass bonded support, a layer composed of 10% oxidized starch, 55% of capsules containing a white spirit type solvent with low aromatic contents (such as DILUTINE MS from SHELL) is deposited by conventional coating means. CHEMISTRY, EXSOL D 145/195 from ESSO CHEMISTRY; boiling point between and 195 C) 12% of calibrated starch serving as a spacer for microcapsules and -23% of kaolin of a coating quality. The microcapsules are obtained by a

  known method, the wall being made of a polyurethane.

  These capsules have a diameter of 10 microns

about.

  The removal required to obtain a bo

  reactivity is around 5 to 6 g / m2.

  The paper thus obtained makes it possible to detect attempts at falsification by scraping or erasing the

  handwritten notes with an erasable ballpoint pen.

  Indeed, under the writing pressure the capsules burst and release the solvent. This dilutes the ink, lowers its viscosity, increases its penetration into the support and above all prevents perfect erasure whatever the type of eraser or scraper used. Thus, after an attempt to erase by scrubbing or scraping, there will always remain at least one colored trace of the handwritten mentions due to the penetration of the ink into the support, itself

  surrounded by a more or less significant blue spot.

Example 2.

  The composition of the layer given in Example 1 is used, in which the solvent of the white-spirit type with low aromatic content is replaced by a solvent of the gasoline type (Essence E from SHELL CHEMISTRY or EXSOL DSP 100-130 from ESSO -CHEMISTRY:

  boiling point between 100 and 130 C).

  We also deposit 5 to 6 g / m2 of layer.

  The behavior is identical to that of the

paper described in Example 1.

Example 3.

  The composition of the layer given in Example 1 is repeated, in which the capsules containing the solvent of the whitespirit type with low aromatic content are replaced by a 50/50 mixture of this solvent.

  with di (2-ethylhexyl) phthalate (DOP from RHONE-

POULENC for example).

  For the same removal of 5 to 6 g / m2 of layer, the same behavior is obtained as in Examples 1 and 2o

Example 4.

  The composition of the layer given in Example 1 is used, in which the 10 micron capsules are replaced by 5 micron diameter capsules.

containing the same solvent.

  The behavior of the paper is identical to that

paper described in Example 1.

Example 5.

  On a mass-bonded support, a layer composed of 12% oxidized starch is deposited by conventional coating means. 46% of 10 micron diameter capsules containing an Essence type solvent (Essence

  E), 9% of calibrated starch and 33% of coated kaolin

chage.

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  -6 With a deposit of 5.5 to 6.5 g / m2, we obtain a paper on which all attempts to erase handwritten notes with an erasable ballpoint pen will leave a sufficiently visible colored trace.

Example 6.

  On a mass bonded support in which

  massively introduced the reagents usually intro-

  duits in security papers which cannot be forged by chemical agents (dyes for example), the layer given in example 1 is deposited in which the reagents usually introduced in a size press (reagents with alkaline agents for example) have been added at the necessary doses to obtain quartities of reagents per m2 identical to those obtained in the

classic security papers.

  The deposition of 5 to 6 g / m2 of layer makes it possible to obtain a paper which is unforgeable on the acid, basic, oxidizing-reducing chemical agents, by the oxidizing-reducing pairs, by the solvents for the conventional writing means and on the other hand on which the erasable writing means will leave a

  very visible colored trace after exfoliation or scraping.

Claims (6)

  1. Security paper usable to fight against falsifications which may occur due to the use of an erasable ink characterized in   what it contains on the surface, microcapsules containing   providing a solvent for said ink 2. Security paper according to claim 1, charac terized in that said microcapsules are incorporated in the coating layer of the paper 3 at 30 to 70% by weight relative to the weight of said coating layer.   3. Paper according to one of the preceding claims -   teeth characterized in that said solvent is chosen from aromatic or aliphatic organic solvents, chlorinated solvents.   4. Paper according to one of claims   above, characterized in that the solvent contains a softener.   5. Paper according to one of claims 2,3 and 4   characterized in that the coating layer comprises from 3 to 20% by weight. relative to the weight of said   layer, of a distance of microcapsules.   6. Paper according to one of claims 1 to 5,   characterized in that it further comprises at least   another known means of combating falsifications.