HU184042B - Chromogenic composition containing pyridyl-blue and substituted phenol - Google Patents

Abstract

The present invention relates to a chromogenic composition for the production of pressure sensitive transcription plates comprising 0.3 to 0.6% by weight of one or more commonly used chromogenic materials, preferably indolyl red, crystal violet lactone or 102-102, and 81 to 96.4% by weight. organic solvents, preferably ethyl diphenylmethane or 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. The composition is characterized in that in addition to the above components 0.3-6% by weight of pyridyls, i.e. 7- (1-ethyl-2-methyl-indol-3-yl) -7- [4-diethylamino-2-ethoxy]. phenyl-5,7-dihydro-furo [3,4-b] pyridine 5-one and / or 5- [1-ethyl-2-methylindol-3-yl] -5- [4- (diethyl) amino) -2-ethoxyphenyl] -5,7-dihydro-furo [3,4-b] pyridin-7-one - and optionally 1-7 atoms in free ortho or para position containing from 6 to 14 carbon atoms also includes phenol or phenols substituted by alkyl, (C 1 -C 5) alkyl or (2- or 4-mono- or 2,4- or 2,6-di (alpha-methylbenzyl)). The use of pyridyl blue and, optionally, phenol, prevents a reduction in the ability of the chromogenic composition to produce a light effect. -1-

Description

The present invention relates to a chromogenic composition for use in the preparation of a pressure sensitive transcription material.

The coloring systems used for pressure-sensitive transcribers generally consist of a substantially colorless chromogenic (i.e., colorant) material, a color developer * (capable of producing a color change in reaction with the chromogenic material), and a solvent (in which the coloring reaction occurs). Reactive components of the coloring system should be kept separate until use. This is usually achieved by microcapsulating a solution of one of them in a solvent. At the time of application, these microcapsules are broken due to the application of pressure and consequently release the solution therein. As a result, the chromogenic material and the color developer are able to interact with each other to produce a color mirror image that exactly matches the shape of the applied pressure transducer. Thus, a pressure-sensitive transcription material can be used for making copies without using carbon copy paper.

Reactive colorant components and solvent can be applied to the transcription sheets in a variety of configurations. In one such arrangement, which may be referred to as a two-component arrangement, a microcapsulated solution of one of the coloring components and the other of the coloring components are mixed with one another, or the same side of the sheet is first another component solution.

Another arrangement, referred to as a transfer arrangement in the literature, is to cover one side of a sheet (referred to as "CB-sheet" in the Anglo-Saxon literature, hereinafter referred to as "CB-type") with a microencapsulated solution of chromogenic material. one page of another page (referred to as "CF-sheet" in the English literature and referred to as "CF-sheet"). The two sheets are then assembled into a series of sheets so that the coated sides are in contact. Thus, when pressure is applied to the uncoated side of the CB-type sheet, the solution is released from the other side to the coated side of the CF-type sheet, thereby undergoing a color reaction. A series of sheets may include one or more intermediate sheets (referred to as "CFB-sheet" in the English literature, hereinafter referred to as "CFB-sheet"), one side of which contains a microencapsulated solution of chromogenic material and the other side of which contains the color developer. is coated. In this way, additional copies are available until the individual sheets are properly arranged to transfer the solution to be transferred from the pressure-sensitive CB-type to the pressure-sensitive CF or CFB-type sheets.

One of the most important properties of both the two-component and the transfer arrangement of the microencapsulated solution of chromogenic material, or in other words the microencapsulated chromogenic solution, is its ability to react with a color developer to produce a reflection of sufficient intensity. In general, most transcription materials containing microencapsulated chromogenic material exhibit satisfactory reactivity provided that they are not exposed to various environmental influences, in particular light. However, after prolonged storage under such effects, all known transcription agents have, without exception, exhibited significantly lower reactivity. This decrease in reactivity, hereinafter referred to briefly as "CB degradation" in the Anglo-Saxon literature, may be further enhanced by the use of certain solvents or chromo gene materials. For example, crystalline bolyalactone - 1,1-bis [4- (dimethylamino) phenyl] -5- (dimethylamino) -1,3-dihydrobenzo [o] furan-3-one (hereinafter referred to as especially in the case of chromogenic solution of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (hereinafter referred to as ")") as the solvent "CVL" as the solvent, the CB degradation is particularly pronounced.

It is an object of the present invention to provide a chromogenic composition for use in the preparation of pressure-sensitive transcripts that exhibit no, or at least reduced, CB degradation.

It has now been found that the object of the present invention can be achieved by a chromogenic composition which according to the invention contains one or more substantially colorless chromogenic substances, a solvent for this chromogenic substance, pyridyl blue and optionally free ortho or para C 6-14 alkyl. Contains phenol or phenols substituted by 2- or 4-mono- or 2,4- or 2,6-di (alpha-methylbenzyl) -phenyl or C1-C5-alkyl.

The use of pyridyl blue and optionally substituted ortho or para substituted phenol provides the chromogenic composition of the invention with resistance to CB degradation. However, the color mirrors produced by the chromogenic composition of the present invention 35 have excellent color fastness (i.e., the mirror images retain their color permanently) and color gradation stability.

Pyridyl blue is a chromogenic material which can be illustrated by the formula shown in the attached drawings, or by a mixture of the two stereoisomers. The compound of the two formulas is generically designated 5- (1-ethyl-2-methyl-3-indolyl) -5- [4- (detylamino) -2-ethoxyphenyl] -5,7-dihydrofuro [3 , 4-b] pyridin-7-one (represented by formula (I)) and 7- (1-ethyl-2-methyl-3-indolyl) -7- [4- (diethylamino) -2- ethoxy45-phenyl] -5,7-dihydrofuro- [3,4-b] pyridin-5-one (II in the drawing).

Each of these two stereoisomers can be used in the chromogenic composition of the invention, but the pyridin-5-one isomer is more effective. However, the use of processes for the preparation of pyridyl blue (see, for example, United Kingdom Patent No. 1,367,567 or U.S. Patent 3,775,424) usually results in a mixture of isomers, and the separation of the individual isomers from this mixture by conventional techniques such as chromatography. heavy, time-consuming and very expensive on an industrial scale. Therefore, it is preferable to use a mixture of isomers, or to use a synthetic method for the preparation of pyridyl blue, wherein the reaction conditions are chosen to favor the formation of the pyridin-5-one isomer.

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Of course, the amount of pyridyl blue used in the chromogenic composition of the present invention should be such as to achieve the desired effect and preferably be between 0.6% and 3% by weight (i.e., 0.6-3 parts by weight of the composition per 100 parts by weight of solvent used).

Examples of suitable phenols include dodecylphenol, 4- (1,1,3,3-tetramethylbutyl) phenol, 2,4-di-tert-butylphenol, 4-cumylphenol or various position isomers. a mixture of styrene-phenols. These phenol derivatives are known and can be prepared in a known manner.

The amount of phenol in the chromogenic composition according to the invention is preferably 1-7, for example 2-5% by weight, i.e. the chromogenic composition contains 2-5 parts by weight of the phenol derivative per 100 parts by weight.

It is advantageous for the chromogenic composition of the present invention to contain both pyridyl blue and reactive phenol for even greater resistance to CB degradation.

Essentially colorless chromogens for use in the chromogenic composition of the invention include 3,7-bis (dimethylamino) -10-benzoylphenothiazine (abbreviated as BLMB), the crystalline violet lactone (abbreviated as CVL), -anilino-6- (diethylamino) 3-methylfluorane (abbreviated as N102), 3,3bis (1-ethyl-2-methyl-3-indolyl) phthalide (hereinafter referred to as indole red), spiro-7-chloro -2,6-dimethyl-3- (ethylamino) -xanthene-9,2- (2H) -naphtho [1,8-bc] furan, 7-chloro-6-methyl-3- (detylamino) ) -fluorane, 3- (diethylamino) -benzo [b] fluorane, 3- [4- (diethylamino) -2-ethoxy-phenyl-3- (2-methyl-1-ethyl-3-indolyl) ) phthalide, 3- [4- (4- (diethylamino) -2-butoxyphenyl) -3- (2-methyl-1-ethyl-3-indolyl) phthalide, and 3,7-bis (diethyl) One or more of the amino-10-benzoyl-benzoxazine In addition to the chromogenic materials listed, pyridyl blue itself can also be used as a chromogenic material because it gives a blue color by reacting with a color developer. n shows resistance to CB degradation, so the combination of pyridyl blue with one of its solvents is considered to be within the scope of the present invention. However, it is preferable to use pyridyl blue in combination with other dyes to achieve the desired shade of color, and is particularly advantageous for partially replacing CVL in existing or developed chromogenic compositions. Particularly preferred are chromogenic compositions comprising BLMB (up to 1.3% by weight), CVU (up to 3% by weight), indole red (up to 2% by weight), and NI 02 (up to 3% by weight) ) containing 0.6-3.0% by weight together with pyridyl blue.

Examples of suitable solvents for the dissolution of chromogenic substances are dialkyl phthalates (the alkyl moiety of which contains from 4 to 13 carbon atoms, such as dibutyl, dioctyl, dinonyl or di (tridecyl) phthalate), TXIB (4,027,065). U.S. Patent No. 3,676,581, ethyl diphenylmethane (U.S. Patent No. 3,996,405), alkyl biphenyls (such as monoisopropyl biphenyl; U.S. Patent No. 3,627,581), _{C] 6 | 4} alkylbenzenes (e.g. dodecylbenzene), diaryl ethers (e.g., diphenyl ether), diaralkyl ethers (e.g. dibenzyl ether), aryl aralkyl ethers (for example, phenyl-benzyl ether), liquid dialkyl ethers containing at least 4 carbon atoms, liquid alkyl ketones having at least 9 carbon atoms, alkyl or aralkyl benzoates (e.g. benzyl benzoate), alkylated naphthalenes, and and partially hydrogenated terphenyls. Most preferred solvents include ethyl diphenylmethane and TXIB. These substantially odorless solvents may be used singly or in combination. They may also be used in combination with a diluent to reduce the cost of producing the chromogenic composition of the invention. Of course, the diluent to be used must be chemically inert to the solvent or any other component of the chromogenic composition and must be at least partially miscible with the solvent (to form a single phase). The diluent is used in an amount which, on the one hand, enables cost savings and, on the other hand, does not impair the solubility of the chromogenic material. Diluents of this nature are well known. A preferred example is Magnaflux oil, which is a saturated hydrocarbon oil that distils between 188 ° C and 260 ° C.

prior to use of the chromogenic composition of the invention, by microencapsulation by any method well known in the art, for example gelatin (see e.g.

800,457 or U.S. 3,041,289), urea-formaldehyde resin (see, e.g., U.S. Patent Nos. 4,001,140, 4,087,376, or 4,089,802) or various melamine-formaldehyde resins (see, for example, U.S. Patent No. 4,100,103).

Color developers useful in conjunction with the chromogenic compositions of the invention are well known in the art. By way of example, the oil-soluble metal salts of phenol-formaldehyde novolac resins of the type described in U.S. Patent Nos. 3,672,335, 3,732,120 and 3,737,410 are mentioned. A preferred example of a resin for this purpose is a zinc-modified oil-soluble phenyl formaldehyde resin such as zinc salt of a resin made from 4-octylphenol and formaldehyde or zinc salt of a resin made from 4-phenylphenol and formaldehyde.

The chromogenic compositions of the invention a

U.S. Patent Nos. 627,581, 3,775,424, and 3,853,869, may be used to form coating compositions or to be overlayed to produce transcription sheets.

The invention is further illustrated by the following embodiments.

Example 1: Preparation of pyridyl blue

A mixture of 0.21 mol of quinoline anhydride (2,3-pyridinedicarboxylic acid anhydride) and 0.33 mol of 1-ethyl-2-methylindole was stirred in a reaction vessel at 65-70 ° C for 3 hours and then cooled with benzene (or chlorine). benzene) to give (1-ethyl-2-methyl-3-indolyl) - (3-carboxy-2-pyridyl) ketone and isme.

A total of 58 g (0.188 mol), 35.3 g (0.188 mol) of N, N-diethyl-m-phenethidine and 250 ml of acetic acid 3184 042 acid anhydride were stirred at 60-65 ° C for 2 hours. The reaction mixture was poured into 500 ml of water and the acetic anhydride was hydrolyzed by slow addition of 450 ml of 29% ammonium hydroxide solution. After stirring for 2 hours, the precipitate was filtered off and washed successively with water, 200 ml of 40% methanol in water and 50 ml of boiling point 60-110 ° C. The precipitate was then dried to constant weight in a 75 ° C oven for a total of 80.5 g (90%) of 7- (1-ethyl-2-methylindol-3-yl).

-7- [4- (diethylamino) -2-ethoxyphenyl] -5,7-dihydrofuro [3,4-b] pyridin-5-one and 5- (1-ethyl-2- methyl indol-3-yl) -5- [4- (diethylamino) -2-ethoxyphenyl] -5,7-dihydrofuro [3,4-b] pyridin-7-one 9: 1 134-137 ° C.

Example 2: Preparation of chromogenic compositions

A series of chromogenic solutions are prepared in the following parts by weight by mixing the components also given below.

Table 1

1 2 3 4 5 6 7 8 CVL 3.4 3.4 3.4 3.4 3.4 3.4 3.4 3.4 Indolilvörös 1.1 1.1 1.1 1.2 1.2 N-102 1.1 1.1 1.1 1.2 1.2 1.2 1.2 1.2 Other chromogenic material - - - 1.2 (a) 1.2 (b) 1.2 (0 - Alkylate 215 ¹ 126.4 126.4 126.4 130.0 130.0 130.0 130.0 130.0 Ethyl-diphenylmethane 68.0 68.0 68.0 60.0 60.0 60.0 60.0 70.0 Dodecylphenol 10.0 4.0 - 10.0 10.0 10.0 10.0 -

Mixture of ^{1 C} 1-5 alkylbenzenes (a) spiro-7-chloro-2,6-dimethyl-3- (ethylamino) xanthene-9,2- (2H) -naphtho 4,8,8-bc] furan (b) 3- (diethylamino) benzo / b / fluorane (c) 7-chloro-6-methyl-3- (diethylamino) fluoran

Table 2

1 2 3 4 5 6 7 8 Piridilkék 0.6 1.2 1.8 2.4 1.2 1.2 CVL 3.4 3.4 2.8 2.2 1.6 3.4 2.8 2.8 indolilvörös 1.1 1.2 1.2 1.2 1.2 1.1 1.2 1.2 N-102 1.1 - - - - 1.1 0.6 Alkylate 215 130.0 130.0 130.0 130.0 130.0 130.0 130.0 200.0 Ethyl-diphenylmethane 70.0 70.0 70.0 70.0 70.0 70.0 70.0 -

Example 3: Preparation of microencapsulated chromogenic compositions

Table 1-16 listed in Tables 1 and 2. Each of the chromogenic solutions of SEQ ID NO: 4,001 is microencapsulated according to the method described in U.S. Patent No. 4,001,140. In brief:

180 parts by weight of chromogenic solution were emulsified in 50 of a mixture adjusted to pH 3.5 containing 35 parts by weight of a 10% aqueous solution of EMA 31 (EMA 31, 75,000, supplied by Monsanto Chemical Co., USA). - 90,000 molecular weight copolymer of ethylene and maleic anhydride), 32 parts by weight of 55% 20% aqueous solution of EMA 1103 (EMA 1103 supplied by Monsanto Chemical Co., molecular weight range of 5000-7000, ethylene and maleic anhydride) ), 133 parts by weight of water, 10 parts by weight of urea and 1 part by weight of resorcinol. After emulsification, 29 parts by weight of a 37% solution of formaldehyde are added to the reaction mixture, which is then stirred in a water bath at 55 ° C. After 2 hours, allow the water bath temperature to cool to room temperature with constant stirring.

Example 4: Preparation of Microencapsulated Coating Compositions

Each of the microencapsulated solutions from chromogenic solutions 1 to 16, prepared in Example 3, is converted into a coating composition with the following qualities and amounts:

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Part Weight (wet) Part Weight (dry) Microencapsulated chromogenic solution 80 40 Grainy wheat starch 10 10 10 s% Penford 230 ¹ ' 40 4 Water 100 -

Penick and Ford Ltd. is a UK based starch based binder based on ether.

Example 5: Preparation of CB type transcription sheets

Examples 1-16 prepared according to Example 4. each of the coating compositions is serially applied to paper as a base material, spread on the paper with the No. 12 cable-shaped roller, and the coating dried with a heat gun.

Example 6: CB Deterioration Comparative Experiments

1-16. each of the CB-type transcription sheets is each subjected to a typewriter intensity experiment (hereinafter referred to as TI). During the experiment, the same letter is typed on a pair of sheets of a CB type and a CF sheet according to the invention (the CF type sheets used in these experiments are described in U.S. Patent 3,732,120 or U.S. Patent 3,737,410). zinc-modified phenolic resin). Thus, a color printed mirror image corresponding to the typed letter is created on the CF-type sheet, and the intensity of the mirror image is determined by means of a transparency meter.

The intensity measured in this way is the degree of color appearance or, in fact, the percentage (fény / Ιθ) of the reflection of the printed mirror image to the non-printed area. Thus, a large value represents a weak color appearance while a small value represents a large color appearance.

The TI experiment was performed immediately before and two hours after irradiation of the CB-type sheets with fluorescent light. In each case, the intensity measurement is performed 20 minutes after the printed mirror image.

The most important part of the equipment used for fluorescent testing is an illumination box that has a row of 18 daytime fluorescent lamps (each 53.3 cm long and rated at 13 watts) mounted vertically on nearly 25 mm central brackets. The CB-type boards are placed at a distance of 2.5-3.8 cm from the lamps.

The results obtained with 16 different CB-type transcription papers are given below:

Change in TI to CB trains with fluorescent light

After CB Transmitter - Initial Handling Page Serial Number TI Hour Manual - 2 Hour Treatment

1 41 - 2 - 6 2 43 - 3 - 7 3 36 -13 -34 4 41 - 6 -15 5 38 - 5 -13 6 38 - 8 -15 7 38 - 5 -10 8 35 -18 -32 9 44 -20 -33 10 41 -17 -29 11 48 -12 -24 12 41 -12 -20 13 47 -12 -19 14 35 -15 -31 15 44 -14 -24 16 46 -14 -24

Of course, the amount of CB degradation that is still acceptable depends on the length of light exposure to the CB coating. For 2 hours of light exposure, the loss or deterioration of more than 26 units is unacceptably high. Thus, the transcription sheets 1, 2, 4, 5, 6 and 7 containing dodecylphenol and the transcription sheets 11, 12, 13, 15 and 16 containing sufficient quantities containing pyridyl blue - still show an acceptable degree of CB degradation. In the case of transcripts Nos. 3, 8, 9 and 14 (which are controls which do not contain CBD resistance material), and transcript Nos. 10 (containing too little pyridyl blue), CBromination is unacceptable. large.

Example 7: Preparation of chromogenic compositions

Further chromogenic solutions are prepared by mixing the following qualities and amounts of components:

component parts piridilkék 2.0 CVL 2.0 indolilvörös 1.2 Alkylate 215 182.0 ethyl-diphenylmethane 6.0 di (n-hexyl) ketone 6.0

In addition to the above components, each chromogenic solution contains 6.0 parts by weight of the following phenols:

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The chromogenic solution ID ^ ^er

17. octylphenol

18. dodecylphenol

19. Cumulophenol

20. Styrene Phenol

21. 4,4-Methylenebis [2- (tert-butyl) -6-methylphenol]

22. 2,4,6- (tri-tert-butyl) phenol

23. 2,6- (di-tert-butyl) phenol

Example 8: Preparation of microencapsulated chromogenic compositions

17-23 of Example 7. Each of these chromogenic solutions is microcapsulated as described in U.S. Patent No. 4,100,103. In particular, we do the following:

200 parts by weight of the chromogenic solution were emulsified in 35 parts by weight of a 10% aqueous solution of EMA 31 (see composition

Example 3) and 140 parts by weight of water adjusted to pH 3.7 and the resulting emulsion was added to 32 parts by weight of 20% (w / w) aqueous solution of EMA 1103 (see Example 3) and 30 parts by weight of water. PH adjusted to 0, and 30 parts by weight of Resimene 714 resin (methylated methylamine melamine resin of Monsanto Chemical Co.) after mixing the latter with EMA 1103 solution. The reaction mixture was then stirred in a 55 ° C water bath for 2 hours and then allowed to cool to room temperature.

Example 9: Preparation of CB type transcription sheets

17-23 of Example 8. Each of the microencapsulated chromogenic solutions of serial number 3 is converted into coating compositions as described in Example 4 and with the materials listed therein, and the paper base is coated with these compositions as described in Example 5.

Example 10: CB Degradation Comparative Experiments

17-23. each of the CB-type transcription sheets is subjected to the same experiments as described in Example 6, with the following results:

Change in T1 CB Coatings Fluorescent LightBuy CB Transcript Sheet After Initial Tongue Treatment TI 1 Hour Treatment - 2 Hour Treatment

17 41 - 2 - 7 18 42 - 4 - 7 19 42 - 5 -11 20 36 - 7 -14 21 38 -23 -34 22 39 -20 -27 23 40 - 3 -13

The transcription sheets 17, 18, 19, 20 and 23 are obviously of satisfactory quality, taking into account the criteria described in Example 6 for judging quality. The transcription sheets 21 and 22 are obviously unsatisfactory because they contain a phenol derivative that is not sufficiently reactive.

Example 11: Preparation of chromogenic compositions

Further chromogenic solutions are prepared by mixing the following qualities and amounts (by weight) of the following components: (See table on the next page.)

Example 12: Preparation of CB Type Transcript Sheets

All. 24-29. Each of the chromogenic solutions was serially microencapsulated as described in Example 3, and the resulting microencapsulated batches were formulated with the additives described therein as described in Example 4, and finally the paper base was coated with these compositions as described in Example 5.

Example 13: CB Degradation Comparative Experiments

24-29. The CB-type transcript sheets were subjected to the experiments described therein as described in Example 6, with the following results:

Change in Tl CB coatings with fluorescent light The CB transcript- Initial after treatment page number YOU 1 hour hand- 2 hour hand- Meeting Meeting 24 43 - 8 -13 25 43 - 8 -14 26 39 -13 -34 27 47 0 3 28 39 - 5 -11 29 46 - 4 - 6

The transcription sheets 24, 25 and 28 containing pyridyl blue have very good resistance to CB degradation. The transcription sheets 27 and 29, which contain both pyridyl blue and dodecylphenol, are extremely resistant to CB degradation. The control copy number 26 (which does not contain CBD anti-spill agent) is unsatisfactory.

Example 14: Preparation of chromogenic compositions

Finally, the following chromogenic solutions are prepared by mixing the following qualities and amounts (by weight) of the following components:

30 31 32 Piridilkék 91.8 91.8 CVL 21.6 21.6 91.8 Indolilvörös 27.0 27.0 14.8

(See page 8 for continuation of the table.)

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14

24 25 26 27 28 29 Piridilkék 2.0 2.0 2.0 2.0 2.0 CVL 2.0 2.0 3.4 2.0 2.0 2.0 Indolilvörös 1.2 1.2 1.1 1.2 1.2 1.2 N-102 - - 1.1 - - - Other chromogenic material - 1.0 (d) - - 1.0 (e) - Alkylate215 200.0 200.0 130.0 190.0 180.0 180.0 Ethyl-diphenylmethane - - 70.0 - - - Dodecylphenol - - - 10.0 - 10.0 Other additives - - - - 20.0 (f) 10.0 (g)

(d) 3,7-bis (diethylamino) -10-benzoylbenzoxazine (e) BLMB (f) methyl nonyl ketone (g) methyl myristate (Continued from Table on page 7)

30 31 32 N-102 16.2 16.2 29.7 2,3,4-trimethyl-l-l, 3- -pentándiol-diizo- butyrate 3495.6 - 3509.1 Magnaflux oil 1747.8 3146.0 1754.6 Dibutylphthalate - 2097.4 -

Weight (dry)

Etherified maize starch based binder 4.25

Poly (vinyl alcohol) binder 4.25

EXAMPLE 75 Preparation of microencapsulated chromogenic composition _3q

30-32 of Example 14. each of the chromogenic solutions was microcapsulated according to a procedure similar to that described in Example 8:

5400 parts by weight of the chromogenic solution were emulsified in a mixture of 1000 parts by weight of a 10% aqueous solution of EMA 31 (see Example 3) and 5600 parts by weight of water adjusted to pH 3.7. The emulsion was then adjusted to pH 4.0 with 1000 parts by weight of a 10% aqueous solution of EMA 40 1103 in pH 4.0 (composition as in Example 3), 1000 parts by weight water and 1000 parts by weight Resimene 714 then the reaction mixture was heated at 55 ° C for 2 hours with stirring. The reaction mixture is then left under stirring until the ambient temperature is reached.

Example 16: Preparation of Microencapsulated Coating Compositions

30-32. each of the microencapsulated solutions prepared from chromogenic solutions in Example 15 is converted into a coating composition with the following qualities and amounts:

Finally, sufficient water is added to adjust the solids content of the coating composition to 17.4% by weight.

Example 17: Preparation of CB Type Transcript Sheets

30-32. Each coating composition is dispersed and layered on a paper base using a semi-industrial airknife coating apparatus and then dried.

Example 18: CB Degradation Comparative Experiments

30-32. The CB-type transcript sheets were subjected to the experiments described therein as described in Example 6, with the following results:

Change in TI of CB Coatings Fluorescent LightBuy CB Transcript Sheet After Initial Tongue Treatment T1 1 Hour Treatment - 2 Hour Treatment

30 46 - 2 - 9th 31 47 - 1 - 3 32 53 -17 -30

Weight (dry)

Microencapsulated solution 70.40

Grainy wheat starch

Considering the criteria described in Example 6 for judging quality, the transcription sheets 30 and 31 containing pyridyl blue have excellent resistance to CB degradation, while the control 32, containing no pyridyl blue, gives unsatisfactory results.

Claims (5)

Patent claims: A chromogenic composition comprising one or more chromogenic substances, preferably 1,1-bis [4- (dimethylamino) phenyl] -5- (dimethylamino) -1,3-dihydrobenzo [o] furan- 3-one, 3,3-bis [4- (dimethylamino) phenyl] -6- (dimethylamino) phthalide, or 2'-anilino-6 '- (diethylamino) -3'-methyl- fluorane, and an organic solvent for chromogenic material, preferably ethyldiphenylmethane or 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, in an amount of from 81 to 96.4% by weight, With 0.6% by weight of chromogenic material, 0.3-6% by weight of pyridyl blue - i.e. 7- (1-ethyl-2-methylindol-3-yl) -7- [4- (diethylamino> 2-ethoxy) phenyl] -5,7-dihydrofuro [3,4-b] pyridin-5-one and / or 5- (1-ethyl-2-methylindol-3-yl) -5- [4- (diethylamino) ) -2-ethoxyphenyl] -5,7-dihydrofuro [3,4-b] pyridin-7-one and optionally 1-7% by weight of free ortho or para-alkyl having from 6 to 14 carbon atoms, (C1-C5-alkyl) -phenyl or 2- or 4-mono Contains phenol or phenols substituted by 2,4- or 2,6-di (alpha-methylbenzyl). 2. An embodiment of the chromogenic composition according to claim 1, wherein the pyridyl blue is 7- (1-ethyl-5-methylindol-3-yl) -7- [4- (diethylamino) -2-ethoxy]. phenyl] -5,7-dihydrofuro [3,4-b] pyridin-5-one. An embodiment of the chromogenic composition according to claim 1, wherein the pyridyl blue is 7- (1-ethyl-2-methylindol-3-yl) -7- [4- (diethylamino) -2-ethoxy]. phenyl] -5,7-di10 hydrofuro [3,4-b] pyridin-5-one and 5- (1-ethyl-2-methylindol-3-yl) -5- [4- (diethyl- amino) -2-ethoxyphenyl] -5,7-dihydrofuro [3,4-b] pyridin-7-one. An embodiment of the chromogenic composition according to claim 1, wherein the phenol is dodecylphenol, It contains 4- (1,13,3-tetramethyl-butyl) -phenol or 4-cumyl-phenol. 5. The chromogenic composition of claim 4, wherein the chromogenic composition comprises from 2 to 5% by weight of phenol.