LU82043A1 - CHROMOGENEOUS MATERIAL - Google Patents

Description

The present invention relates to a chromogenic material, methods for its preparation, as well as a pressure sensitive recording element containing this chromogenic material.

Typically, in color forming systems used in pressure sensitive recording elements, substantially colorless chromogenic material is used, a color developer capable of reacting with the chromogenic material to produce a color, as well as a solvent in which the color formation reaction can take place. The reactive components of the color forming system are separated from each other until the time of use and, for this purpose, a solution of one of these components is normally enclosed in microcapsules (usually the chromogenic material) in a solvent. At the time of use, the application of pressure causes the rupture of these microcapsules which, under the effect of this pressure, release this solution, thus allowing the two chromogenic components to come into reactive contact. one with the other by forming a color image corresponding exactly to the image of the pressure applied. In this way, a pressure sensitive recording element can be used to obtain copies without having to use carbon paper.

There are generally two types of recording systems in which pressure sensitive recording material is used. In one of these types, called "autonomous recording system", the recording element consists of a sheet comprising a layer of a color developer mixed with microcapsules j - 3 - containing the solution of a chromogenic material in a solvent · Alternatively, the color developer and the chromogenic solution in microcapsules can be dispersed inside the sheet itself.

In the other type of recording system, called "transfer recording system", at least two recording elements are used. In the most widely used normal transfer recording system *, one recording element comprises a sheet comprising a layer of the chromogenic solution in microcapsules ("CB sheet"), while the other consists of a sheet having a layer of a color developer ("CF sheet"), In the reversible transfer recording system, the color developer and not the color material is coated in microcapsules in the form of a solution in a solvent. Consequently, a recording element comprises a sheet comprising a layer of a solution of a chromogenic developer in microcapsules ("CB sheet"), while the other recording element consists of a sheet comprising a layer of a pigment insoluble in water and practically neutral chemically on which the chromogenic material is adsorbed · The "CB sheet" and the "CF sheet" are assembled in the form of a set for multiple copies, the layers of these sheets being in a relationship of contiguity so that the transfer of the solution into a solvent can take place from the "CB sheet" to the "CF sheet".

In order to obtain additional copies, the set for multiple copies may also include a third recording element consisting of a sheet on one side of which is applied a "CB layer", "- 4 -

One or more of these sheets ("CFB sheets") are placed between the "CF sheet" and the "CB sheet" of the set for multiple copies, each "CB layer" being in a relationship of contiguity with a "CF layer".

In order to obtain an image having particular optical characteristics, different chromogenic materials are normally used in combination. One of the most common of these is crystal-violet violet lactone (3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide) which is used in combination with other chromogenic materials to obtain a blue image or a black image. However, crystallized violet lactone has a low resistance to color fading, i.e. it has a low ability to impart resistance to color dissipation in an image formed from this substance. . In addition, after exposure to ambient conditions, in particular to light, the crystallized violet lactone undergoes a significant reduction in chromogenic reactivity, that is to say its ability to form an image of acceptable intensity during the reaction. with a color developer. This reduction in reactivity (whether or not by putting the material into microcapsules) is often called "CB reduction" in the case of a normal transfer recording system and, moreover, it may be greater. if the material is used in the form of a chromogenic solution in certain solvents such as the di-i-buty-rate of 2,2,4-trimethyl-1,3-pentane-diol (ΤΧΐΒ). Despite these drawbacks, crystallized violet lactone has continued to be widely used in the absence of any other industrially acceptable varian.

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It is an object of the present invention to provide a chromogenic material which can be used as a total or partial replacement for crystallized violet lactone, this material having better resistance to color loss, as well as better ability to prevent reduction reactivity,

The present invention provides a chromogenic material of formula: '* * £ 0λ,., 5- (1-éthy1-2-méthy1indol- 7- (l-éthyl-2-méthy1indo1- 3-yl) -5- (4 ~ diethylamino-2- 3-yl) -7- (4 “diethylamino-2- ethoxyphenyl) -5,7-dihydro-ethoxyphenyl) -5,7-dihydro-furo (3,4-b) pyridin-7-one furo (3.4 “b) pyridin-5-one

In addition to its better resistance to color fading and its better ability to prevent reduction in reactivity, the chromogenic material of the present invention, which is called "pyridyl blue", is also able to provide rapid color formation and give a blue color of excellent intensity and a very stable shade of coloring. In addition, this material has a very low reactivity with respect to the backing paper. This characteristic is important because, when used with a normal transfer system, there is a minimum or even zero "CB discoloration", this discoloration being - Ο - Λ j! "CB sheet" and the chromogenic solution which may not have been transferred.

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î Either of the two isomers above can be used as the chromogenic material, although the iso-! jj) mother of pyridin-5-one is the most useful. It is, however, more convenient to use a mixture of isomers in which j! ! the pyridin-5-one isomer predominates. This characteristic is due to the fact that the process adopted to carry out the synthesis of the chromogenic material, gives a mixture of this type while the subsequent separation of the isomers by! * classic techniques is difficult, time-consuming and! expensive on an industrial scale.

The present invention also provides a process for the preparation of the chromogenic material defined above! jj above, this process consisting in reacting a keto-acid! "of formula:

CO

èf '"with a compound of formula: t

B - H

i · t.

j where one of the symbols A and B represents a 4-diethylamino- * 2-ethoxyphenyl group, while the other represents a group • i 1-ethyl-2-methylindol-3-yl,, 1 rj:! in the presence of a dehydrating agent.

A suitable type of dehydrating agent is an acid anhydride such as acetic anhydride; moreover, the reaction is preferably carried out at a temperature! ” high, for example between 65 and 75 ° C.

When A represents an 1-ethyl-2-methylindol-3-yl group, the keto acid is prepared by reacting quinolinic anhydride with 1-ethyl-2-methylindole and the reaction is usually carried out temperature between 60 and 70 ° C.

When A is a 4 “diethylamino-2-ethoxyphenyl group, the keto acid is prepared by reacting quinolinic anhydride with N, N-diethyl-m-phe-netidine. The reaction is usually carried out in a solvent in the presence of a catalyst such as aluminum chloride, as well as at a temperature between 35 and 40 ° C.

Preferably, A is an 1-ethyl-2-methylindol-3-yl group because then the keto acid can be prepared without solvent and without catalyst. In addition, the two-step process which results in higher production of the pyridin-5-one isomer than the two-step process in which A is a 4-diethylamino-2-ethoxyphenyl group. Indeed, the preferred method makes it possible to obtain a mixture in which the pyridin-5-one isomer intervenes therein at a rate of at least 90% and even at a rate of 95% ·

The present invention provides another process for preparing the chromogenic material defined above, this process consisting in reacting quinolinic anhydride, 1-ethyl-2-methylindole and N, N-diethyl-m-phenetidine together in presence of a dehydrating agent such as those mentioned above.

This process is less preferred, however.

Of course, the chromogenic material of the present invention can be combined with other chromogenic materials in order to obtain a particular shade and coloration - ö - in the developed image. The combination obtained benefits from the incorporation of the chromogenic material of the present invention, because it gives this combination an ability to prevent loss of reactivity. Among these other materials, there are, for example, one or more of the following: j 337-bis (dimethylamino) -10-benzoyl-phenothiazine (benzoyl-leucomethylene blue, BLMB), 2'-anilino- 6'-diethylamino-! Lj 3'-methylfluorane (N102), 3j3 ~ his (l-ethyl-2-methylindol- 3-yl) -phthalide (indolyl red), 3,3-bis (l- butyl-2- ^ methylindol-3-yl) phthalide, spiro-7-chloro-2,6- * dimethyl-3- j ethylaminoxanthene-9,2- (2H) naphthol (1,8-bc) furan, 7-chlor ►i 6-methyl-3-diethylaminofluorane, 3-diethylaminobenzo (b) -fluorane, 3- (4-diethylamino-2-ethoxy) -3- (2-methyl-1-ethyl-indol-3 -yl) phthalide, 3- (4-diethylamino-2-butoxy) -3- (2-: methyl-1-ethylindol-3-yl) phthalide and 3,7-bis (diethylamino '110-benzoyl-benzoxazine In addition, the chromogenic material of the present invention can be used with, and instead of, crystalline violet lactone i.

\ j For a standalone recording system or, | j a normal transfer recording system, the material? chromogenic of the present invention is used individually; or in combination with a chromogenic solution in micro-capsules. Among the organic solvents suitable for forming a chromogenic solution are, for example, dialkyl phthalates, the alkyl groups of which contain 4 to 13 carbon atoms, for example, dibutyl phthalate 1-5 dioctyl phthalate, dinonyl phthalate and ditridecyl phthalate, 2,2,4-trimethyl-1,3-di-i-butyrate; pentane-diol (TXIB, patent of the United States of America n ° - y - of America n ° 3,996,405) * alkyl-diphenyls such as mono-i-propyldiphenyl (patent of the United States of America n ° 3.627.581), alkyl-benzenes whose alkÿl groups contain 10 to 14 carbon atoms, for example, dodecyl-benzene, diaryl ethers such as diphenyl ether, diaralkyl ethers such as dibenzyl ether , as well as arylaralkyl ethers such as phenyl-benzyl ether, liquid dialkyl ethers containing at least 8 carbon atoms, liquid alkyl ketones containing at least 9 carbon atoms, alkyl or aralkyl benzoates such as benzyl benzoate, alkylated naphthalenes, as well as partially hydrogenated terphenyls. Preferred solvents are ethyldiphenylmethane and 2,2,4-trimethyl-1,3-pentane-diol di-i-butyrate.

These solvents, all of which are practically odorless, can be used individually or in combination. They can also be used with a thinner to reduce the cost price. Of course, the diluent must not be chemically reactive with the solvent or one or the other chromogenic material and it must be at least partially miscible with the solvent in order to form a single phase. The diluent is used in an amount sufficient to obtain an economic advantage, without altering the solubility of the chromogenic material ·

Diluents are already known in the art and a preferred example of diluent is "Magnaflux" oil which is a mixture of saturated aliphatic hydrocarbon oils distilling at a temperature between 160 and 288 ° C.

The amount of chromogenic material which must be used according to the present invention in the chromogenic solution depends of course on the particular conditions but, as a general rule, a useful quantity is between 0.6 and by weight (this is i.e. parts by weight of chromogenic material per 100 parts by weight of solvent) The coating of the chromogenic solution in microcapsules can be carried out by methods known in the art, for example, using gelatin as described in the patents of the United States of America Nos. 2,800,457 and 3,O4I,289, using a urea / formaldehyde resin as described in the patents of the United States of America No. 4,001,140, 4,087,376 'and 4,089,802, as well as using different melaminc / formaldehyde resins as described in US Patent No. 4,100,103.

Color developers which can be used with the color material of the present invention are known in the art and do they? include acid clays, as well as metal salts (oil-soluble) of novolak resins · phenol / formaldehyde of the type described in US Pat. Nos. 3,672,935, 3,732,120 and 3,737. 410, A preferred example of a suitable resin is a zinc-modified, oil-soluble phenol / formaldehyde resin, for example, the zinc salt of a p-octylphenol / formaldehyde resin or the zinc salt of '' a p-phenylphenol / formaldehyde resin.

For a reversible transfer system, the chromogenic material of the present invention is not coated * in microcapsules in the form of a chromogenic solution, but it is adsorbed on a pigment insoluble in water and practically neutral chemically as described in British Patent No. 1,337.9 "-! · The color developer, which may be a resin-based chromium developer as indicated above, is however coated in a microcapsule, - 11 - d coating in suitable microcapsules include those mentioned above

The present invention also provides a pressure sensitive recording element containing the chromogenic material defined above as a component of its color forming system.

Formulations and casting methods for the preparation of the pressure-sensitive recording element are generally known in the art [(see, for example, British patent 1,337 * 924 "as well as US patents - United States of America No. 3 * 627,581, i 3,775,424 and 3,853,869.

The present invention will be described below i with reference to a number of examples in which all the parts are by weight.

j: Example 1 - Preparation of the chromogenic material For 3 hours, at a temperature of 65 to 70 ° C., 0.21 mole of quinolinic anhydride and 0.33 mole of 1- are mixed together in a reaction flask. ethyl-2-methylindole. The reaction mixture is then cooled and washed with benzene (or chlorobenzene) to obtain 0.19 mole of (L-ethyl-2-methylindol-3-yl) (3_carbox3 pyridin-2-yl) ketone and its isomer.

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For 2 hours, at a temperature of 60 to 65 ° C, stirred 58 g (together \ 0.188 mole) of (1-ethyl-2-methylindol-3-yl) (3-carboxypyridin-2-yl) ketone and its isomer with 35.3 g (0.188 mole) of N, N-diethyl-m-phenetidin <and 25Ο ml of acetic anhydride. The reaction mixture is poured into 500 ml of water and the acetic anhydride is hydrolyzed by slowly adding 450 ml of ammonium hydroxide at $ 29. After stirring for two hours, the -1 /.- methanol is filtered at 40 # and 50 ml of petroleum ether (boiling point: 60-110 ° C). Then the solid is dried in the oven at 75 ° C to a constant weight to obtain a 9: 1 mixture of the pyridin-5-one compound and the pyridin-7-one compound (80.5 g; 90 # J melting point: 134-137 ° C)

Example 2 - Preparation of the chromogenic material

For 4 hours, a mixture of 3.62 g (combined $ 0.0117 mol) of (l-ethyl-2-methylindol-3-yl) (3 “Carboxypyridin-2-) is stirred and heated to 60 ° C. yl) ketone and its isomer, as well as 2.26 g (0.0117 mole) of N, N-diethyl-m-phenetidine with 17 ml of acetic anhydride. The reaction mixture is poured into 150 ml of water containing 18.4 g of sodium hydroxide. The hot reaction mixture is vigorously stirred (50-60 ° C) for one hour, then filtered. The product obtained is washed several times with water, with 10 ml of water / methanol at 30 # and finally with petroleum ether (boiling point: 60-110 ° C). A 20: 1 mixture of the pyridin-5-one compound and the pyridin-7-one compound (5.66 g; melting point: 148-150 ° C.) is obtained. Example 3 - Preparation of the chromogenic material

For 5 hours, a mixture of 3.75 g (0.01096 mole) of 2'-carboxypyrid-31-yl- (4 ~ diethyl-amino-2-ethoxyphenyl) ketone, of 1 is heated to 75 ° C. , 74 g (0.01096 mol) of r l-ethyl-2-methylindole and 35 ml of acetic anhydride. The reaction mixture is poured dropwise into 250 ml of water containing 38.8 g of sodium hydroxide. After stirring for a few hours, the product is filtered. It is washed several times with water and finally with petroleum ether. 3.37 S (65 #) of the desired chromogenic material is obtained, in which the thin layer chromatography (silica) reveals the presence of a very small amount only of the pyridin compound — 7 * "one ·

The reaction proceeds in the same way when mixed keto acid isomers are used, but then the product obtained contains a larger amount of the pyridin-7-one compound.

Example 4 Preparation of Chromogenic Solutions

A number of chromogenic solutions are prepared by mixing the following components in the parts indicated:

Table 1 -i- -3- -2- _â_ _5_ .6 7

Pyridyl blue - 1.2 1.8 2.4 - 1.2 1.2

Crystalline violet lactone 3.4 2.8 2.2 1.6 3.4 2.8 2.8

Indolyl red 1.1 1.2 1.2 1.2 1.1 1.2 1.2 2'-anilino-6'-di-ethylamino-31 - methylfluorane 1.1 - _ _ j ^ 0 ^ _

Alkylate 215 * 130.0 130.0 130.0 130.0 130.0 130.0 200, (

Ethyldiphenylmethane 70.0 70.0 70.0 70.0 70.0 70.0 - 10. n_ i2_

Pyridyl blue - - 2.0 2.0 - 2.0

Crystallized violet lactone - 3.4 3.4 2.0 2.0 3.4 2.0

Indolyl red 1.1 l, 2 J> 2 ^ ^ ^ 2 ’-anilino-6’-di-ethylamino-31- methylf luorane 1.1 i ^ ^ ^

Other chromogenic material - ^ * nr \,. , l, 0 (a) - l, 0 (b)

Alkylate 215 126.4. „A30.0 200.0 200.0 130.0 180.0

Ethyldiphenylmethane 68.0 ‘jo _ 9/0> o - - 70.0

Airhrp + -. * Î - * Alkyl-benzenes with alkyl groups containing 10 to - 14 - 15 carbon atoms · (a) 3 * 7 ~ bis (diethylamino) -10-benzoyl-benzoxazine * (b) Benzoyl blue -leucomethylene.

(c) Methyl myristate #

Example 5 - Preparation of chromogenic solutions in microcapsules #

Each of the chromogenic solutions 1 to I3 is coated in microcapsules in accordance with the method described in the patent of the United States of America No. 4 * 001 # 140 # In summary, the procedure is as follows:

180 parts of the chromogenic solution are emulsified in a mixture of 35 parts of “EMA 31” at 10% (ethylene / maleic anhydride copolymer with a molecular weight ranging from 75 * 000 to 90 * 000, sold by “Monsanto Chemical Co # '') in water, 32 parts of” EMA II03 ”at 20% (ethylene / maleic anhydride copolymer with a molecular weight in the range from 5 # 000 to 7 * 000, sold by “Monsanto Chemical Co * n) in water, 133 parts of water, 10 parts of urea and 1 part of resor-cinol, the pH being adjusted to 3 * 5 * After emulsification , 29 parts of formaldehyde are added at $ 37 and the mixture is placed in a water bath at 55 ° C. while stirring. After r 2 hours, the temperature of the water bath is allowed to equilibrate with room temperature while maintaining agitation * Example 6 - Preparation of microcapsule casting formulations *

Each charge of microcapsules 1 to 13 is completed in a casting formulation using the following materials in the parts indicated: / f / '"Λ i. -Parties Parts (in the wet state) (in the state st I Load of capsules 80.40

Wheat starch granules 10 10! * "Penford 230" at 10% 40 4

Water 100 * Etherified corn starch binder made by "Penick and Ford Ltd.".

Example 7 - Preparation of "CB" recording elements ·

We disperse each of the casting formulations | 1 to 13 3 we apply them on a paper support and I spread them with a n ° 12 coating bar, then we dry the layers with a gun ·

| Example 8 - Comparative Reactivity Reduction Tests "CB

Each of the recording elements "CB" 1 to 13 is subjected to the intensity test with the typewriter (Tl) in which a standard model is typed on a set for multiple copies comprising a "CF sheet" and a "sheet i! CB "(on the" CF sheet "of the tests, a zinc-modified phenolic resin is poured as described in the patents of the United States of America n ° 3 * 732.120 and 3 · 737 · 410)" In this way, we obtain a color image corresponding to the model on the "CF sheet" and determine the intensity of the image using "an opacimeter * 'The intensity is a measure of the chromogenic development and it is the ratio between the reflecting power of the printed image and that of the unprinted area (i / lo), this ratio being expressed as a percentage. A high value indicates a low chromogenic development and a low value indicates a high chromogenic development / Λ \! s is * - x 6 -

The intensity tests are carried out with a typewriter before the exposure of the "CB sheet" to irradiation with fluorescent light, as well as after one and two hours of exposure of the "CB sheet" to this irradiation * In all cases, intensity measurements are made 20 minutes after image formation *

The device used for the fluorescent light tests comprises a light box comprising a bench of 18 fluorescent "daylight" lamps (length 533 cm; nominal wattage: 13 watts) mounted vertically on 25.4 mm central supports. * The "CB sheets" are placed 2.5-3.8 cm from the lamps * The results obtained for the thirteen "CB" recording elements are given below ï

Value element Change of the Tl value after initial registration exposure to light from the layers - "CB" n ° Tl ches "CB" _

Exhibition during Exhibition during 1 hour during 2 hours 1 44 “20 -33 2 48 -12 -24 3 41 -12 -20 4 47 —12 -19 5 35 -15 -31 6 r 44 -14 -24 7 46 -14 -24 8 36 -13 -34 9 35 -18 -32 10 43 -8 -13 11 43 -8 -14 12 39 -13 -34 13 39 -5 -11 y / ^ - 17 -

The acceptable value for the reduction in reactivity "CB" obviously depends on the duration of exposure of the "CB sheet" to light * For an exposure for 2 hours, a loss of more than about 26 units constitutes a value too much high. Consequently, the recording elements 2, 3, 4, 6, 7, 10, 11 and 13 which contain pyridylex blue exhibit a reduction in reactivity "CB" sufficiently small to be acceptable * The recording elements 1, 5 * 8, 9 and 12 which are controls which do not contain pyridyl blue, all exhibit a reduction in reactivity "CB" which is much too high.

Example 9 Preparation of Chromogenic Solutions

Additional chromogenic solutions are prepared by mixing the following components in the parts indicated: 14 15 16 j Pyridyl blue - i

Crystallized violet lactone 21.6 21.6 91 * 8

Indolyl red 27 * 0 27.0 14 * 8 2'-anilino-6'-diethylamino- 3'-methylfluorane 16.2 16.2 29.7 | 2,3,4-trimethyl-1,3-pentane-diol diisobutyrate 3 "495.6 - 3" 509.1

"Magnaflux" oil 1,747.8 3-146.0 1 * 754.6

Dibutyl phthalate - 2,097.4 -

Example 10 - Preparation of chromogenic solutions in microcapsules *

Each of the chromogenic solutions 14 to 16 is coated in microcapsules in accordance with the process described in US Patent No. 4-100 * 103- The specific process is as follows: ί Λ i - 18 -

5 * 400 parts of a chromogenic solution are emulsified in a mixture of 1 * 000 parts of "EMA 31" at 10 # in water and 5 * 600 parts of water by adjusting the pH to 3.7 · On then sets the pH of the emulsion to 4 * To this emulsion, a mixture of 1,000 parts of "EMA 1103" is added to 10 # in water (pH adjusted to 4)> of 1,000 parts of water and 1,000 parts of "Resimene 714" · The mixture obtained is heated to 55®C for 2 hours * At the end of this period, the temperature of the mixture is allowed to equilibrate with room temperature while maintaining agitation.

Example 11 Preparation of microcapsule casting formulations *

Each of the charges of microcapsules 14 to 16 is completed in a casting formulation using the materials below in the parts indicated:

Parties (in the dry state

Load of capsules 70.40

Wheat starch granules 21.10

4 * 25 etherified corn starch binder

4 * 25 polyvinyl alcohol binder

Sufficient water is added to obtain a casting formulation containing 17 * 4 # of solids.

Example 12 - Preparation of "CB" Record Items

Each of the casting formulations 14 to 16 is dispersed and poured onto a paper support using an air knife coating apparatus from a pilot installation, then it is dried.

Example lj - Comparative tests for reduction of reactivity "CBrt The recording elements" CB "14 to 16 are subjected to the same tests as those described in Example 8.

4 - 19 -

Recording element- Value Change in value Tl after registration "CB" initial exposure of layers "CB" to n ° Tl light ____ '------ 7-

After exposure - After exposure for 1 hour 2 hours! 14 46 -2 -9 15 47 -1 -3 16 53 -17 -30

By adopting the acceptability guidelines described in Example 8, the recording elements 14

Iet 15 containing pyridyl blue have excellent resistance to reduction of reactivity "CB", while the control not containing pyridyl blue (element I of recording 16) gives unsatisfactory results "

Example 14 - Preparation of a recording element "CF" with pyridyl blue which is used in an invertible transfer system "(a) 1 g of pyridyl blue is dissolved in 150 ml! of acetone then, in the solution thus obtained, 70 g of precipitated calcium carbonate carbonate, 20 g of "Cabolite 100" (pigment of urea / formaldehyde resin, United States patent n ° 3 * 988.522): and 10 g of zinc oxide ("Green Seal 8" from "New Jersey Zinc! Co.", EUA) and then the dispersion obtained is allowed to dry in a. hood.

i (b) The product of step (a) is completed in i i a casting formulation with the following ingredients in the proportions indicated: '·' i ίΛ i ("i i t j i i - 20 -

Parts by weight% by weight In the state In the state (in the dry state> wet dry____

Product of 1 * step (a) 84 84 83 * 4 "Penford Gum 260" 100 10 9 * 9 (modified corn starch)

Latex "Dow 620" 12 6 6.0 (carboxylated styrene / butadiene latex) "Tamol 731" 3 0.75 0.7 (25% solution of the sodium salt of a polymeric carboxylic acid, sold by • "Rohm & Haas")

Water 250,449 100.75 100.0 (c) The formulation obtained is poured onto a sheet of bond paper at 15.42 kg with a bar of "Mayer" n ° 12, then dried. The dry weight of the layer is about 2.04 kg per ream of 500 sheets measuring 63 * 5 x 96.5 cm). Example 15 - Preparation of a recording element "CF" with crystallized violet lactone which is used in an invertible transfer system.

The procedures of steps (a), (b) and (c) of Example 14 are repeated, with the exception that the • pyridyl blue is replaced by crystallized violet lactone. EXAMPLE 16 Another Process for the Preparation of a “CF” Recording Element with Pyridyl Blue, (a) In a “Attritor” grinder, for 45 minutes, 300 g of pyridyl blue, 600 g of carbonate calcium, 300 g of "Penford Gum 230" (modified corn starch) having a solids content of 10%, 30 g of "Tamol 731" having a solids content of 25% and 1,200 g of water, while adding a few drops of octanol to reduce foaming,

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- 21 -! (b) The product of the step is then completed! (a) in a casting formulation with the following ingredients! in the proportions indicated:; Parts by weight% by weight In state In state 1, wet dry dry state

Product of step (a) 6.3 2.0 3.0

Calcium carbonate 43.4 43.4 65 * 8

"Ansilex" clay (United States Patent No. 3,586,523) 9.9 9.9 15.0 "Penford Gum 230n 66.0 6.6 10.0

"Dow 620" latex 8.0 4.0 6.0 "Calgon T" 0.1 0.1 0.1 (molten powder composition of zinc / sodium phosphate glass) j

Water 110.3 244.0 66.0 99.9

Solid content of the layer; 2 d Viscosity: 58 centipoise.

(c) The formulation obtained is poured onto a sheet of support paper at 15.42 kg using an air knife coating device, then dried. The dry weight j of the layer is approximately 2.04 kg per ream of 500 sheets! measuring 63.5 x 96.5 cm · I; ; - Example 17 - Another method of preparing an element of! I registration "CF" with crystal violet lactone · -! I read.

! ! The procedures of steps (a), (b) and (c) of Example 16 are repeated, with the exception that the pyridyl blue is replaced by crystallized violet lactone,. while also replacing the 300 g of carbonate of r> o1 11m ri A T I "ma i n \ ΟΛΛ J - JL * J_ -. J _. * _ - 22 -

The solid content and the viscosity of the casting formulation are 27/2 and 57 centipoise respectively.

Example 18 - Preparation of "CB and CFB sheets" based on acid resins "(a) While heating and stirring, 1,200 g of p-phenylphenol resin are dissolved in 3 * 200 g of dibenzyl ether and 1,600 g of "Magnaflux" oil · 200 g of "EMA 31" (ethylene / maleic anhydride copolymer with a molecular weight in the range of 75,000 to 90,000) are dissolved in 1,800 g of water demineralized while heating and stirring · The solution obtained from "EMA” is diluted with 6,000 g of demineralized water and the pH is adjusted to 4 with a sodium hydroxide solution at $ 20. Then, the oily solution is emulsified of p-phenylphenol resin in the solution of "EMA" with a "Cowles" solvent at 25 ° C. The emulsification is continued until droplets of oil are obtained with an average granularity of approximately 2 microns and with a total particle size between about 0.5 and 15 microns, then the emulsion obtained is transferred to a water bath set at a temperature of 55 ° C and, while stirring rapidly, 1,000 g of 80% "Resloom 714” (methylol — etherified melamine) diluted with 1,000 g of demineralized water are added. The mixture obtained is kept at a temperature of 55 ° C. for 2 hours with constant stirring to form capsules. After 2 hours, the temperature is allowed to equilibrate slowly with room temperature. Agitation is continued for an additional 16 hours.

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(B) The solution of p-pjiphenylphenol resin is then completed in a solvent and in microcapsules in a casting formulation with the following ingredients in the proportions indicated:

Parts by weight% by weight - (in the dry state) wet dry

Capsules from step (a) 26.60 12.50 71.4

Starch "Stilt” $, 20 3.12 17.9

"Stayco S" starch 6.30 0.63 3 * 6

"Dow 638” latex (carbo- latex 2.50 1 * 25 7 * 1 xylated styrene / butadiene) I Water 26.40 65.00 17 * 50 100.00

Solid content of layer î 2 *]%

Viscosity: 68 centipoise · (c) The formulation obtained is poured onto a sheet of ^ ^ support paper at 15.42 kg using an air knife coating device, then dried · The dry weight of the key is approximately 1.7 kg per ream of 500 sheets! measure 63 * 5 x 96.5 cm · In addition, pour the formulation L,.

on 1? dorsal side of the recording elements prepared according to the methods of examples 16 and 17 in order to form: "CF B sheets" · t t

Example * "- 19 - Preparation of another" CB sheet "based on an acidic resin · (a) An oily solution of 1 * 400 g of p-octylphenol re> in 3,200 g of is prepared dibenzyl ether and l.tOO g of "Magnaflux" oil while heating and in sufficient agitation * --- * 'mIient to ensure dissolution · Then, the oily so "-ttion is coated in microcapsules by adopting the process

J A ~. to 1 I p + .anf "(a Ί Ha 1 I AYAmnl b 1 R

(b) and (c) The procedures of steps (b) and (c) of Example 18 are repeated, with the exception that 27.30 (instead of 26.60) parts by weight are used (at wet) capsules of step (a) with p-octyl-phenol resin, while the formulation is used only to prepare "CB sheets".

EXAMPLE 20 Comparison of Recording Elements with Pyridyl Blue and Crystallized Violet Lactone Recording elements with Pyridyl Blue and Crystallized Violet Lactone were subjected to the intensity machine machine test. write in which a standard model is typed on a set for multiple copies comprising a "CF sheet" and a "CB sheet", and possibly an intermediate "CFB sheet". In this way, we obtain a color image corresponding to the model on the "CF sheet" or on the "CF side" of a "CFB sheet", then we determine the intensity of the image using an opacimeter.

Intensity is a measure of chromogenic development and is the ratio between the reflectivity of the printed image and that of the unprinted area (i / lo), this ratio being expressed as a percentage. A high value indicates a low chromogenic development and a low value indicates a high chromogenic development In order to compare the recording elements with pyridyl blue and with crystallized violet lactone, the following intensities are determined: A - The initial intensity, i.e. the intensity of a printed image 24 hours after its initial development * h: B - The intensity of an image after exposure: (i) to fluorescent light, (ii) to light natural solar, p (iii) at ambient conditions, or 3 days.

; (iv) inside an oven.

C - The intensity of an image formed on a sheet after prior exposure: (i) to fluorescent light, (ii) to natural sunlight, | (iii) at ambient conditions, or j; (iv) inside an oven.

! The device used to carry out the fluorescent light tests comprises a light box containing a bench of 18 fluorescent "daylight" lamps (length 53 53 * 3 cm with nominal wattage: 13 watts) mounted vertically on central supports of 25 , 4 "" "· We place the sheets with or without the image at a distance of 2.5 to 3.8 cm from the lamps for 48 hours. We perform the image formation with a typewriter" IBM Executive "using a 4-bar crosshatch character.

The leaves are exposed with or without the image to sunlight by placing them for 48 hours in a south-facing window. Image formation is performed with an "IBM Memory" typewriter! -using an "X" character, || The leaves are exposed with or without image to the ambient conditions by suspending them: ; on a laboratory wall for 7 ^ 9 weeks, periods during which the leaves are subjected to air, to the natural and fluorescent light of the room, at temperature 1; ! air and moisture content. We carry out the formatio n 1 j; ' î - ^ \ image with an "IBM Selectric" typewriter using a solid character.

The leaves are exposed inside an oven for 3 weeks at a temperature of 60 ° C.

Imaging is performed with an "IBM Executive" typewriter using a 4-bar crosshatch character ·

The results obtained are as follows:

Base sheet Element of acid resin resin registration A B (i) C (i)

Example 18-CB Example 16-CF 38 48 55

Example 18-CB Example 17-CF 51 74 78

Example 18 and Example 18 and example lô-CFB example 16-CFB 49 51 56

Example 18 and Example 18 and Example 17-CFB Example 17-CFB 52 68 75 _A B (ii) C (ii)

Example 18 — CB Example 14-CF 4P 41 65

Example 19 — CB Example 14 — CF 52 53 75

Example 18 — CB Example 15 — CF 40 52 88 /

Example 19 — CB Example 15 — CF 56 74 96 A B (iii) C (iii) 7 weeks

Example 18-CB 'Example 16-CF 33 38 48

Example 19-CB Example 16-CF 44 56 54

Example 18-CB Example 17-CF 34 45 72

Example 19 — CB Example 17-CF 57 73 89 A B (iii) Ç (iii) 9 weeks

Example 18 — CB Example 16 — CF 32 42 44

Example 18-CB Example 17-CF 34 54 76

Example 18 and Example 18 and example 16 — CFB example 16 — CFB 33 42 45

Example 18 and Example 18 and / ^ ovoemlp 1 p.xp.mnle 1 7-CFR 75 55 76

Base sheet Element of acidic resin registration A * B (iv) C (iv); j - - - -. - r -,.. ---,.. I.

\

Example 18-CB Example 16-CF 40 49 * 52 Λ J Example 18-CB Example 17-CF 48 49 75 i | i Example 18 and Example 18 and i example 16-CFB example 16-CFB 48 45 51

Example 18 and Example 18 and • Example 17 — CFB Example 17-CFB 51 51 68 From the above examples and, in particular, from Examples 8, 13 and 20, it can be seen that the chromogenic material of the present invention brings considerable progress compared to crystallized violet lactone, In particular, an image obtained from this material has better resistance to color fading and the material itself is much less sensitive to light, so much so that it keeps its j longer! reactivity. In addition, in the reversible transfer system, the recording element containing pyrxdyl blue can form an image of higher intensity than a recording element containing crystallized violet lactone, i: / - v! s- fl \ / ^ 1 \ ^ i ^ i 1 n I j:! 'i.

'î i> ï

Claims (27)

1 · Chromogenic material of formula: / "t2" S Jo) "J> VS fo) v vT N '- * 2. Chromogenic material according to claim 1, characterized in that it comprises a mixture of 7 * ~ (l ~ ethyl-2-methylindol-3-yl) -7 ~ (4-diethylamino-2-ethoxyphenyl) - 5, 7-dihydrofuro (3,4-b) pyridin-5-one and 5- (1-ethyl-2-methylindol-3-yl) -5 “(4 ~ diethylamino-2-ethoxyphenyl) -5 to 7“ dihydrofuro (3 f4-b) pyridin-7 ~ one 3 · Chromogenic material according to claim 2, characterized in that the pyridin-5-one isomer predominates · 4 · Chromogenic material according to claim 3. characterized in that the pyridin-5-one isomer is involved at least 90% in the mixture. 5 · Chromogenic material according to claim 4, characterized in that the pyridin-5-one isomer is involved in an amount of at least 95% in the mixture, 6, La 7- (1-ethyl-2-methylindol-3-yl) -7- (4_ diethylamino-2 ~ ethoxyphenyl) -5 9 7-dihydrofuro (3, 4-b) pyridin-5-one, 7 · 5 “(1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5 9 7-dihydrof uro (3 * 4 ~ b) pyridin- 7-one, v 8, A method of preparing a chromogenic material according to any one of claims 1 to; 7, characterized in that it consists in reacting a keto-i! acid of formula: | KtA n \ -C00H U i | with a compound of formula ï i B - H ιού one of the symbols A and B represents a 4-diethylamino-2-ethoxyphenyl group, while the other represents a 1-ethyl-2-methylindol-3-yl group, in the presence dehydrating agent * 9 · A method according to claim 8, characterized in that the dehydrating agent is an acid anhydride. 10. Method according to claim 9> characterized in that the acid anhydride is acetic anhydride. 11. Method according to any one of claims 8 to 10, characterized in that the reaction is carried out at a temperature between 65 and 75 ° C. 12. Method according to any one of claims 8 to 11, characterized in that A represents an l-ethyl-2-methylindol-3-yl group, while the keto acid is prepared by reacting with quinolinic anhydride with 1-ethyl-2-methylindole. 13 · Process according to any one of claims 8 to 11, characterized in that A represents a 4-diethylamino-2-ethoxyphenyl group, while the keto acid is prepared by reacting quinolinic anhydride with N, N-diethyl-m-phenetidine. 14 · A method of preparing a chromogenic material according to any one of claims 1 to 7, characterized in that it consists in reacting quinolinic anhydride, l-ethyl ~ 2-methylindole and N, N-diethyl-m-phenetidine together in the presence of a dehydrating agent. 15. A chromogenic material obtained by the process according to any one of claims 8 to 14. 16. A pressure-sensitive recording element containing, as a component of its color forming system, the chromogenic material which is the subject of or prepared by the process according to any one of claims 1 to 14 · 17 · Chromogenic material used as an agent in order to prevent the loss of chromogenic reactivity of the crystallized violet lactone or of another chromogenic material simultaneously present, namely compound 7 ~ (l ~ ethyl— 2-methylindol-3 ~ yl) ~ 7 ~ (4-diethylamino-2-ethoxyphenyl) -5 * 7-dihydrofuro (3j4 ~ b) pyridin-5-one and / or the compound 5- (l-ethyl- 2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7 ~ dihydrofuro (3,4-b) pyridin-7-one. 18. A chromogenic material which is the subject of or prepared by the process according to any one of claims 1 to 14 * this material being used in accordance with claim 17. 19 · Chromogenic material used as an agent for preventing loss of resistance to color weakening of crystallized violet lactone or of another chromogenic material simultaneously present, namely compound 7- (1-ethyl-2 -methylindol-3-yl) -7 “(4“ diethylamino-2-ethoxy-phenyl) -5.7 “éihydrofuro (3 * 4“ b) pyridin-5-one and / or the compound Ç- (1 — ethvl —2— methvlindol — .7 — vl) -ζ— (4-diethvlamino — 2 — ethoxv- 20. Chromogenic material forming X * object or prepared by the process according to any one of claims 1 to 143 used in accordance with claim 19 * 21, A method for improving the ability of a recording element to resist reduction in chromogenic reactivity, characterized in that it comprises the step of incorporating, in the color formation system of this recording element and together with crystallized violet lactone and / or one or more— "eurs several other chromogenic materials, the compound 7 ~ - (l-ethyl — 2— i methylindol-3-yl) ~ 7 ~ ( 4 “diethylamino-2-ethoxyphenyl) -5 3 7“ 'dihydrofuro (3j4-b) pyridin-5-one and / or the compound 5- (l-ethyl- 2-methylindol-3-yl) -5 “(4 -diethylamino-2-ethoxyphenyl) -5,7 ”[dihydrof uro (3» 4-b) pyridin-7-one · 22. Method according to claim 21, J characterized in that the incorporated material is that which is the object of or prepared by the method according to any one! of claims 1 to 14 · j 23, Method for improving the ability of a recording element to oppose the reduction in resistance to hue weakening, characterized in that it includes the step of: incorporate, in the sys-! I teme of color formation of this recording element i and together with crystallized violet lactone and / or one or more other chromogenic materials, the compound 7- (1-ethyl-2-methylindol-3-yl) - 7 “(4-ethylamino-2-ethoxyphenyl) - 5,7-dihydrofuro. (3,4-b) pyridin-5-one and / or the compound d 5- (1-ethyl-2-methylindol) 3-yl) -5- (4 - di ethyl amino -2 - ethoxy- 'phenyl) -5,7-dihydrofuro (3,4-b) pyridin-7-one. i / I ** y 'j * 24. snivan-t method of claim 23, characterized in that the material incorporated is that which is the subject of or prepared by the method according to any one of claims * 1 to 14 * 25. Recording element obtained by the method according to any of claims 21 to 24. 26. A chromogenic material according to claim t9 in substance as described in the above specification with reference to either of the examples. 27. A process for preparing a chromogenic material according to claim 1, in substance as described in the above specification with reference to one or other of the examples · LVÀVvâ. v,%