DE2112380A1 - Reproduction material for making copies containing an invisible image and means for developing the invisible image - Google Patents

Description

concerning

Reproduction material for making copies, containing an invisible image and means for developing the invisible image

The invention relates to ain system for the production of copies containing invisible images, and which is capable of forming ^ier intensity for developing the invisible image on the copy, said system containing an intermediate product of a Leukofarbe with an acid Lewis'sehen a Farbstofl ° , as well as a Lev / is's acid, where the two components, namely the ieuco dye intermediate and the Lewis's acid, can be present in the elements including the copying paper and the marking material.

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The invention relates to materials, elements and methods that are based on testing and information systems of invisible and possibly also visible images are used.

Such products are used wherever there is What matters is to develop a hidden or invisible image, i.e. in the context of examination and self-study materials and for various other purposes in the context of learning, testing, playing and joking or the like. An example for reproduction materials with invisible images as learning aids is one of the correct ones The answer contains a corresponding picture and one or more components are required for visualization when marking with a corresponding writing material, which contains a further component for the necessary color development, whereby allows a correct answer to appear visually. However, one can get a correct answer in all possible ways Reaching questions, with the correct answer appearing even if the student answers them incorrectly, in order to thereby to stimulate the learning process.

Such learning aids are already known (USA patent specification 3 451 143) or have been proposed (German application P 19 44 739 and P 19 52 433).

In the known hidden image systems, one is generally used for its development or visualization Marking fluid applied. According to the older proposal (P 19 44 739), the marking material is preferably one aqueous solution of an iodized salt which is applied to a copy paper containing parts of an invisible image of an oxidizing substance, as well as a recording material, which allows for a color wrap, such as thickness. Will now the

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iodide-containing marking solution on the latent image of the copy sheet applied, the iodide is oxidized to free iodine, which reacts further with the starch, creating a color image high intensity developed.

The use of liquid marking agents is due to inexpedient to the frequency of the spillage. Also can the display sometimes not be unique. Finally, the devices or agents that are wetted with the liquid substances dry out and become ineffective. Various attempts have been made to use such a system hidden image, containing only solids, but these attempts have so far been unsuccessful So it has already been proposed that such a system with a pen containing an iron salt for the development of a latent or hidden image, made from Propylgalat or the like »but such a system is not stable, especially in a humid atmosphere.

The invention now brings a two-component system for the manufacture and development of hidden or invisible Images, which can be used in practice, quickly di ^ provides visible images and the developed images make their way through higher color intensity. The materials of the invention have better shelf life and stability among widely varying Conditions relating to temperature and humidity. she can be used to produce a large number of copies using standard printing processes that reveal the hidden image, optionally together with a visible image.

According to the invention, as a latent image developer serve a solid.

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The two-component system according to the invention acts they are duplicating materials containing an intermediate of a leuco dye and a Lewis acid for development this leuco dye intermediate «In this reaction the color is formed.

According to the invention, the leuco dye intermediate product be contained in the developing or marking compound, the Lewis acid is then in the copy paper in the form of a hidden or latent image. As anyone skilled in the art will understand, these two essentials can be understood Components are exchanged for each other, i.e. the leuco dye intermediate product can be, for example, in the hidden image and the Lewis acid in the labeling material for the development of the hidden image built up by the leuco dye intermediate.

The term "Lewis ¹ see acid" covers compounds which have a high electron affinity and then show the tendency to take up electrons and thus to act as electron acceptors. These properties generally have organic compounds with one or more highly polar groups, such as the carboxyl, keto, quinone, ester group, the acid anhydride group, nitro, cyano groups and halides, and also a number of inorganic CiTe ³ A ¹¹ ] ? e ^ te ro po3.yacids uud their salts. This type of grouping also includes the substituted amines, oximes, imides and diazo compounds.

In practice, the Lewis acid used for the duplication material according to the invention is, in particular, the Ζ, ^ - droxy-benz-oe, bile, uenzoe, citric, phthalic acid, 2, k. Dihydroxy-? C «topheno: i, diphenyl carbazide, antipyrine proven.

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In addition, 2, ^ -dihydroxyacetophenone, Diphenyl carbazide, antipyrine. The sour clays including Kaolin, pyrophyllite, etc., furthermore phosphotungstic acid, tricarboxylic acids, 3-dibromosuccinic acid, the Salicylic acid, succinic acid and benzenesulfonic acid, In addition, Lewis acids are the following substances usable: quinones such as p-benzoquinone, 2,5-dichlorobenzoquinone, 2,6-dichlorobenzoquinone, chloranil, naphthoquinones 1,4 ·), 2,3-dichloronaphthoquinone- (1,4), Anthraquinone, 2-methylanthraquinone, 1, ^ - dimethyl-antrachinon, 1-chloranthraquinone, anthraquinone-2-carboxylic acid, -1,5-dichloranthraquinone, l-chloro-4-anthraquinone, Phenanthrenequinone, acenaphthenquinone, pyranthrenequinone, chrystene -quinone, thionaphthenquinone, anthraquinone-1,8-disulfonic acid and Anthraquinone-2-aldehyde, triphthaloyl-benzaldehyde such as broraal, 4-nitrobenzaldehyde, 2,6-dichlorobenzaldehyde-2, ethoxy-1-naphthaldehyde, Anthracene-9-aldehyde, pyrene-3-aldehyde, oxindole-3-aldehyde, Pyridine-2,6-dialdehyde, diphenyl - ^ - aldehyde, organic phosphoric acids such as 4-chloro-3-nitrobenzene-phosphoric acid, nitrophenols such as ^ -Nitrophenol and picric acid; Acid anhydrides, e.g. the vinegar, Amber, maleic, phthalic acid, tetrachlorophthalic acid, perylene-31 ^ i9 »10 and chrysene-2,3 »8» 9-tetracarboxylic anhydride, dibromo-

ide
maleic anhydride} Metal halogen of the metals and metalloids of group Ib ₁ II to VIII of the periodic table, e.g. aluminum chloride, zinc chloride, iron (III) chloride, tin di- or tetrachloride, arsenic trichloride, antimony pentachloride, magnesium chloride, magnesium chloride, Calcium bromide, manganese chloride, cobalt (II) and (HI) chloride, copper bromide, cerium chloride, thorium chloride, arsenic tri-

id °
iodidj Borhalogsn v / ie boron trifluoride, trichloride, ketones such as acetophenone, benzophenone, 2-acetylnaphthalene, benzil, benzoin, 5-benzoylaccnaphthene, biacendione, 8-acetylanthraene, 9-benzoylamino-cyno- acetylanthracene, k- (^ - , Acetoacetanilid, Indandione- (1,3) ι (1 $ 3-Diketo-hydrinden), Acenaphthalin, QuinondiChlorid, Anisil, 2,2-Pyridil and Furil.

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Other Lewis acids are mineral acids, v / ie the hydrohalic acids, sulfuric and phosphoric acids, the carboxylic acids, v / ie acetic acid and its derivatives, v / ie ionochloric, dichloro, trichloroacetic acid, phenylacetic acid and 6-methylcoumarinyl acetic acid-C ^)} ISalein, cinnamon, benzene, 1- (4-diethylaminobenzoyl) -benzene-2-carboxylic acid, phthalic acid and tetraehlorphthalic acid, aCß-dibroin-ß-formyl-acrylaic acid (mucobromic acid), dibromomaleic acid, 2-bromobenzenic acid ,. üallenic acid, 3-nitro-2-hydroxyl-1-benzoic acid, 2-nitrophenoxy-acetic acid and -benzoic acid, 3-nitrobenzoic acid, ty-nitrobenzoic acid, 3-nitro- ^ - ethoxybenzoic acid, 2-chloro-4- nitro-l-benzoic acid , 3-nitro-l ~ ⁱ riiethoxybenzoesäure, ^L \ ~ nitro-1-methyl-benzoic acid, 2-chloro-5-nitro-lbenzoesäure, 3-chloro-6-nitro-l-benzoe.säure, k-chloro-3 -nitro-1-benzoic acid, 5-chloro-3-nitro-2-hydrox5' -benzoic acid, k- chloro-2-hydroxy-benzoic acid, 2, 1-dinitro-1-benzoic acid, 2-broin-5-nitrobenzoic acid , ^ - chlorophenylacetic acid, 2-chlorocinnamic acid, Z- cyanocinnamic acid, 2 _f k- dichlorobenzoic acid, 3t5-diiii * tro-benzo. Acid, 3,5-oleitrosalicylic acid, malonic acid, mucic acid, acetocalicylic acid, benzilic acid, butanetetracarboxylic acid, cyclohexene 9,10-dichloro-otearic acid, cyanoacetic acid, cyclohexanedicarboxylic acid, fumaric acid, itaconic acid, levulinic acid, malic acid, succinic acid, tX-bromostearic acid, citraconic acid, succinic acid, pyrene-2,3 »7i8-tetracarboxylic acid, ^ / monoic acid> organic sulfonic acids - Toluene and benzenesulfonic acids, for example 2,4-dinitro-1-methyl-benzene-6-, 2,6-dinitro-1-hydroxy-benzene-, 2-Nitro-1-hydroxy-benzene- ⁱ 4 -, ^ -Nitro-l-hydroxy-benzene-5-i 6 ~ Nitro-4-methyl-l-hydroxy-banzol-2-, 4-chloro-'l-hydroxy-benzene-3-, 2-chloro-3- nitro-l-methyl-benzene-5- and 2-chloro-l-methylbenzene - ^ - sulfonic acid.

Also included are the substances tetrabromophthalic acid monoethyl ester, tetracyanoethylon, s-fricyanobenzene, Male insäurSpi ^nl Fh thalic acid imide, p-chlorobenzene diazocyanimide, n-pheny / hydroxylamine, K, N-diethy / hydroxylamine and numerous others.

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1098-1 / 1649

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A large number of precursors or intermediates of the leuco dyes can react with a Lewis acid in a manner desired according to the invention, developing color. For the purposes of the invention, precursors of the intermediate products of the leuco dyes are understood to be colorless substances which are able to develop a color through reaction with a Lewis acid, the precursor or intermediate acting as an electron donor According to the invention usable precursors or intermediates which are the n-phenyl derivatives of leucoauramine N- ^ is ^ Jt p-dimethylaminophenyl) ine thyl aniline, derivatives of bis (p-dimethylaminophenyl) methane and the like According to US Pat. No. 2,981,733, the N-bis _w ip-dialkylaminoaryl) methyl heterocyclic compounds of the formula

are to be designated. In the formula, the substituents R ^, R ^ ₁ mean Ro, R _; * Alky! Groups with 1 to 5 carbon atoms and the grouping

a seeded, nitrogenous heterocyclic with at least 5 ring links.

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Substances of this type are available on the market. In addition, however, essentially colorless dye precursors (CP-2, CP-4, CP-6, CP-21-Y, CP-22-R, Copy Violet A from Du Pont, Copy Violet Lactone and Benzoylleucomethylene Blue, Developer B ₁ NC-Blue-No.1, NC-Orange-No.1, Color

Precursor CP-H »NC Ked-No. 2, rhodamine lactam ₍ color precursor

CP-M, NC-G re en-No. 1, NC-Blue-No .. 2 and Vermilion,) apply.

As already mentioned above, in practice the leuco dye precursor is preferably incorporated into the marking material, preferably in a pen, an ink or as a coated paper as a dry marking material. ' If the marking material is a solid mass in which the leuco dye precursor is incorporated, so is it is generally desirable to mold this together with a solid wax into a pen. Suitable for it a wide variety of waxes including paraffin wax and carnauba wax, but also synthetic waxes such as polyalkylene glycol, in particular polyethylene glycol, polypropylene glycol and ivlethoxynolyethylene glycol. It is particularly preferred the polyethylene glycol. The main requirement of these waxes is that they are solid at room temperature. It is often desirable to use wax mixtures to remove the to achieve the desired degree of fineness of the marking material in order to be able to rub the dye precursor onto the hidden üilo. containing copy, eliminating contact with the Lewis's see acid present in the image to develop color leads. The amount of dye precursor in the wax is not critical and is in the order of magnitude from 0.5 to 20 parts by weight of intermediate product to 100 parts by weight of wax.

The marking material made up as a pen can now be built upon to develop a hidden image a Lewis acid. This will

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completely avoided the use of a liquid marking compound, as was previously necessary. If necessary, can but you can also use the marking material as a flowable mass process for use in felt-tip pens, ballpoint pens and the like. It's expedient this. Case that To disperse leuco dye precursor in a wax which is flowable at room temperature. In flowable marking compounds is the proportion of dye precursor in general 0.1 to 5 parts by weight per 100 parts by weight wax.

In a further embodiment, the marking compound can be provided in the form of a paper with a corresponding coating. - lying, which is rubbed off over the hidden image. In the process, dye precursor is transferred to the copy of the image and by the presence of Lewis acid the hidden image developed. These coated papers can be constructed in the usual way, for example a paper with a coating a mass of dye precursor dispersed in the wax with an appropriate solvent. The proportion of dye precursor in this case is 0.1 to 20 parts by weight per 100 parts by weight of solvent and wax.

Some embodiments according to the invention are described in more detail using the following examples.

Making a pen

A pen is made by melting the

Wax components and adding the dye precursor according to the following recipe.

9 parts by weight of polyethylene glycol, molecular weight 4000 2 parts by weight of polyethylene glycol, molecular weight 1000 0.5 parts by weight of the leuco dye product CP-I

Allied Chemical
This mass is brought into the shape of a pen.

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Production of a flowable marking liquid

98 parts by weight of polyethylene glycol, molecular weight 200, were mixed with 2 parts by weight of the above dye precursor. This mass can be used in pens, felt-tip pens and the like.

Production of a marking breading

It became a!. Let the following composition on Piece of paper applied!

25 parts by weight of sperm oil,

30 parts by weight of carnauba wax and parts by weight of dye precursor.

The amount applied is expediently such that the coating is at least 0.1, preferably 0.5 to 50% by weight of the coated Paper.

As repeatedly stated above, in the preferred embodiment of the invention the Lewis acid is present in the copy in the form of a latent or hidden image. So you can apply the Lewis ¹ acids by printing or stamping inks.

Soluble stamp mass

35 parts by weight of butanol I96 parts by weight of glycerol 195 parts by weight of water 84 parts by weight of citric acid

Dispersible oil 112 parts by weight of glycerine 110 parts by weight of water 10 parts by weight of butanol 60 parts by weight of gum arabic 60 parts by weight of starch

10 drops of preservative ("dioxin") 150 parts by weight of phthalic acid

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The starch is heated and stirred until it dissolves or a formation of a colloidal dispersion! into which the remaining components are then introduced, e.g. in a Ball or colloidal mill.

Instead of the starch, other binders, such as polyvinyl alcohol, carboxymethyl cellulose and the like, can also be used can be applied. The proportion of Lewis acid in the stamp material is up to 60% by weight, preferably 10 to 40 Gew.-yi.

The above stamp colors can be applied to the paper copy with a rubber stamp. However, there are also the most diverse, other printing processes are possible, such as screen printing, light printing (jet printing) or letterpress printing. The image of the dried The stamp or printing ink is invisible. The development is done by treating the lild areas with a of the above mentioned marking materials.

The invention is explained in more detail using the figures. Fig. 1 shows the perspective partial view of a copy with the invisible image.

Fig. 2 shows a partial perspective view of a copy with both the latent and the visible image. 3 shows a partial perspective view of the copy according to FIG 2 after the treatment of a part with marking compound.

Fig. 1 shows a duplication or copy IU that a hidden or invisible image 12 carries. According to Fig. 2 is In addition to the image 12 according to FIG. 1, there is also visible information or test questions 14 and a number of boxes Io for Answers to the relevant questions are provided.

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The box indicating which of the correct answer or question is printed with an invisible or latent image material, but its presence can be seen in the Examination does not determine. The student now selects one of the boxes as his answer and gives it a Mark 18 using one of the marking compounds as above mentioned containing a leuco dye intermediate. Is the box selected the one that reads the "with the help of Lewis." If it contains an acid-formed latent image, the intermediate dye will be react with this, developing the dye, leaving a permanent record of the correct answer is present. However, if the student has marked another box, there will be none in this apart from the marking material different color occur. A permanent record of an incorrect The answer can, if desired, be achieved by using a marking material which is a color pigment the color of which is different from the color of the developed leuco dye. As indicated above, can all boxes with a latent image from a leuco dye intermediate The correct answer appears regardless of which box is marked.

According to the invention, a wide variety of customary printing processes can be used, for example planographic printing, the Lewis ¹ see acid being in the printing ink, which preferably wets the image areas of the printing surface in contrast to the non-image, hydrophilic parts that have been previously moistened with water . In the case of matrix duplication, the Lewis acid can be found in the duplication compound which is applied to a copy sheet through the openings of the stencil to build up the invisible image. In the context of a letterpress printing process, the Lewis acid can be found in the fountain water with which the printing plate is moistened before the printing process.

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In gravure printing, the Lewis "can see in the acid mass is _f which is retained in the etched areas of the printing plate and is transferred from there onto the copy paper by direct contact therewith.

In the foregoing only printing processes were mentioned in which the Lewis acid is in the working fluids. It goes without saying! if the hidden image is to be built up from the leuco dye precursor, then this must be in the above-mentioned organic liquids instead of the Lewis acid.

As mentioned above, the Lewis acid "and exchange the leuco dye precursor with regard to their presence, the Lewis acid in the marking material and the dye precursor is in the ink to build up the hidden or invisible image in the copy. Examples of this embodiment of the invention are given below.

Hers Settin g a marking pen

A mass containing 10 parts by weight of polyethylene glycol (molecular weight ^ 000), 3 parts by weight of polyethylene glycol (molecular weight 1500) and 1 G.ew "-part 2, ^ - Dihydroxyacetophenon, is shaped into a pen or the like. In this embodiment * ·: of the invention is the Lewis' marriage Acid preferably in the wax pin compound in an amount of 1 to 30 parts by volume of Lewis acid to 100 parts by volume of wax.

Production of a flowable marking guideline

For this purpose, a mixture of 100 parts by weight of polyethylene glycol is used (Molecular weight 200) and 5 parts by weight of 3 - bromosuccinic acid applied, the proportion of Lewis acid in 100 parts of liquid wax being about 0.1 to 10 parts.

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Production of a marking daioier

A mass of 6 parts by weight of sperm oil, 30 parts by weight Carnauba wax and 8 parts by weight of phenylcarbazide was used as Layer applied to paper.

For this embodiment of the subject matter of the invention is located the Le uko dye precursor in the JJruekf a.rbe to build a hidden or invisible image on top of the copy. Examples of such printing or stamping masses can be serve the following.

Loosely colored or stamped breed

kO parts by weight of butanol,
200 parts by weight of glycerin,
200 parts by weight of water and
0.5 part by weight of leuco dye intermediate CP-2

Dispersible printing or stamping material 100 GeWo parts glycerine,
100 parts by weight of water,

10 parts by weight of butanol,

60 parts by weight gum arabic,

50 parts by weight starch,

10 drops of preservative dioxin and 33 parts by weight of Leuko dye precursor CP-4-

According to the invention, it is particularly advantageous that either the leuco dye precursor or the Lewis see Acids present in the hidden image copy are essentially colorless prior to development. But should the material making up the hidden picture has a slight or weak coloring, this can be easily hidden, by using a tinted copier or printing paper, preferably des the same shade as the picture is applied.

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Instead of the Lewis's mentioned here in the recipes Acids can be used all of the above in the appropriate amounts. The same applies to the leuco dye precursors in equivalent sounds

. Claims

109841/1649

Claims (1)

Godfather nta η sayings 1) Duplicating material for the production of copies, containing an invisible image, containing a two component system, characterized in that one component is a leuco dye precursor and the other component is a Lewis acid which reacts with one another to produce a dye of high intensity capable of forming, and one of the components is in the copy sheet and the other in a marking material. 2. Duplication material according to claim 1, characterized in that the Lewis acid is a organic compound with one or more groups in the form of carbonyl, ketone, quinone, ester, acid anhydride, nitro, Cyano, substituted amine, oxime, imide or diazo group or is a halogen atom. 3. duplication material according to claim l, characterized in that the Lewis ¹ see acid is an inorganic compound in the form of an inorganic acid, heteropolyacid or salts thereof. ¹ Ir, duplicating material according to Claims 1 to 3, characterized in that the leuco dye intermediate product is essentially colorless. - 17 - 109841/1649 ORIGINAL INSPECTED ^C0PY - 17 - 'lA-39 5. duplicating material according to claim k _t, characterized in that the leuco dye intermediate product e ine ii-bis (p-ijialkylaminoary 1) me thy 1-he terο cy clis before compound. 6. Reproduction material according to claim 1 to 5 »characterized in that the leuco dye intermediate product in a marking material, in particular made of Wax, is located. 7. duplicating material according to claim 6, characterized in that it is not in a fixed position .Wax mass 0.5 to 20 Gew.-j ^ Le uko dye precursor are located. 8th'. Reproduction material according to claim 6, characterized characterized in that there are 0.1 to 5% by weight / a of leuco dye precursor in a liquid composite material. 9., reproduction material according to claim 5 to 7t thereby characterized in that the marking material represents a coating on a paper or a pen. 10. Duplication material according to claim 1, since the Lewis's see acid as a hidden image on the copy paper located what it is as printing ink or soluble or dispersible Ink has been applied. 11. Duplication material according to claim 10, characterized in that the printing ink or ink contains up to about 60 wt .- ^, preferably 10 to ^ O wt .- / "Lewis acid. - 18 -109841 / T649 - lS-. LA-39 2 oil 12. Recording material according to claims 1 to 51 thereby characterized in that the Lewis acid in a marking material, preferably consisting of a V-axis is located. 13 · Recording material according to claim 12, characterized characterized in that the fixed V / axle is used as marking material 1 to 30 parts by weight of Lewis acid 100 parts V / axle contains. 14, recording material according to claim 12, characterized It is marked that the liquid V / ax has 0.1 to 10 parts by weight of Lev / is acid as the marking compound Contains 100 parts wax. 15 · Method of producing the invisible image bearing copies by planographic printing, screen printing, gravure printing or letterpress printing according to claims 1 to 109841/1649