CS226702B2 - Chromogeneous material - Google Patents

Description

- 1 - OJ 226 702

The invention relates to a chromogenic material comprising at least one chromogenic component and at least one organic solvent of these chromogenic components.

Typical systems used in pressure sensitive recording materials typically consist of a substantially colorless chromogenic material, a developer that reacts with the endogenous material to form color, and a solvent in which the color reaction occurs. The reactants of this system are kept separately. This is usually achieved by encapsulating the solution of the chromogenic component into the microcapsules. At the time of applying the pressure, the pressure sensitive microcapsule breaks out and the solution of the chromogenic component contained in these microcapsules is mixed with the developer, whereupon the reaction of the chromogenic component and developer develops a dye at the pressurized sites. In this way, for example, it is possible to obtain a copy on the recording material in the form of a copy sheet (i.e., a sheet under the original sheet) without the use of angled paper.

Said recording material consists, for example, of a paper sheet, on the surface of which a layer of a mixture of microcapsules containing separately a solution of the chromogenic component and the developer is coated. The microcapsules containing the chromogenic solution and the developer may also be dispersed directly in the recording material sheet. - 2 - 220 702 At least two recording materials can also be used for making copies. One such material is, for example, a sheet of paper which is coated with a layer of micro-capsules containing a solution of the chromogenic component (hereinafter referred to as the donor sheet), and the second recording material comprises, for example, a sheet of paper which is coated with a developer coating (this sheet will be referred to below). as an acceptor sheet). The two sheets are placed on top of each other so that their coatings touch and transfer the solution of the chromogenic component from the donor sheet to the acceptor sheet under pressure. In the production of more than one copy, it is possible to include a spool and other recording material, which is formed, for example, by a sheet of paper coated on one side with a layer of micro-capsules containing a solution of chromogenic component and a coating of developer on the other side. One or more of these acceptor-donor sheets are placed between the donor and acceptor sheets such that the side of the sheet containing the microcapsule layer containing the chromogenic component solution is located against that side of the other sheet on which the developer coating is coated. In this way the original is obtained on the donor sheet and copies are obtained on the acceptor-donor sheets and on the acceptance sheet.

Whether any of these systems is already in use, one of the important properties of the chromogenic solution contained in the microcapsules is its reactivity, that is, its ability to produce an image in response to developer-tolerable color intensity. In general, most recording materials containing microcapsules containing solutions of chromogenic components have sufficient reactivity when these materials have not been exposed to environmental conditions, particularly light.

After prolonged exposure to external conditions, the recording materials have much lower reactivity. This reduction in reactivity may be particularly significant when using certain solvents or certain specific chromogenic components. For example, a crystalline lactone lactone solution in 2,2,4-trimethyl-1,3-pentanediol diisobutyrate loses its reactivity very significantly upon exposure to light.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a chromogenic material useful in pressure sensitive recording materials, which material should be resistant to reactivity loss due to external influences. The aforementioned drawbacks do not have a chromogenic material consisting of at least two chromogenic components and at least one solvent of chromogenic components according to the invention, the principle of which is that - as one of the chromosomes - -

Biogenic components include 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b-7-pyridin-7-one] and / or 7- (1-ethyl-2-methylindol-3-yl) -7- (4-dimethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one. The two isomers are referred to as pyridyl.

Preferably, the inventive chromogenic material still contains a free reactive phenol. Preferably, the chromogenic material of the invention comprises phenol with free ortho or para free reactive phenol. Preferably, the chromogenic material according to the invention contains, as the free reactive phenol, dodecylphenoil, p-1,1- 3,3-tetramethylbutylphenol, 2,4-di-tert-butylphenol, p-ketylphenol or styrene-substituted phenol.

The chromogenic material according to the invention preferably contains a free reactive phenol phenol in an amount of 1 to 7% by weight, in particular 2 to 5% by weight.

The chromogenic material of the invention preferably comprises 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridine -7-on and / or - 5 - 226,702 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-thioxyphenyl) -5,7-dihydrofuran 3,4-b-17-pyridin-5-one in an amount of 0.6 to 3% by weight.

The chromogenic material of the invention is preferably contained in microcapsules. An advantage of the chromogenic material according to the invention is that the use of pyridyl blue optionally in combination with a free reactive phenolate results in an increased resistance of the chromogenic material to the loss of reactivity. Mi-moto are images obtained using the chromogenic material of the invention, highly resistant to darkening and very stable. Pyridyl blue may take the form of one of the two isomers of the following general formulas:

the corresponding 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one 226,702 Θ

corresponding 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one in chromogenic material According to the present invention, it is possible to use these isomers, although the pyridin-5-one isomer is more effective, and methods for producing pyridyl blue, such as those disclosed in British Patent 1 367 567 and U.S. Patent No. 3,775,424, result in a mixture of both isomers and isolation of one of these isomers. it is very difficult, time-consuming and hence costly to use this mixture in a conventional manner, for example by chromatography, and it is therefore preferable to use the mixture obtained in such a way that the production of pyridyl blue is carried out under conditions which favor the formation of said more efficient isomer. In this way, a mixture is obtained which can be used to produce the ohromogenic material of the present invention and wherein the more efficient isomer predominates.

The amount of pyridyl blue used in the chromogenic material should be sufficient to achieve the above-described effect and is preferably in the range of 0.6 to 3% by weight based on the weight of the chromogenic material.

For example, phenol with a free reactive bond is a phenols free ortho or para position. Phenols of this type are commonly substituted with any straight-chain or branched alkyl group, an arylalkyl group or an aryl-alkenyl group. Specific examples of such compounds may be dodecylphenol, p- (1,1,3,3-tetramethylbutyl) phenol, 2,4-di-tert-butylphenol, p-cumylphenol and stylized phenol. These phenols are known and can be prepared by conventional techniques.

The phenol is preferably used in an amount of 1 to 7, in particular 2 to 5% by weight, based on the mass of the chromogenic material.

In order to achieve the greatest possible resistance of the chromogenic material to the loss of reactivity, it is advantageous to use both pyridyl blue and phenol with a reactive bond in the chromogenic material simultaneously. The substantially colorless chromogenic component which may be used in the chromogenic material of the present invention is pyridyl blue, for example, 3,7-bis- (dimethylamino) -10-benzoylphenothiazine, 3,3-bis- (dimethylaminophenyl) -6-dimethylaminophthalide, 2 3-bis- (1-butyl-2-yl) -2-methyl-6-diethylamino-3'-methylfluorane, 3,3-bis- (1-ethyl-2-methylindol-3-yl) phthalide; methylindol-3-yl) phthalide, spiro-7-chloro-2,6-dimethyl-3-ethylaminoxanthene-9,2- (2H) naphthol (1,8-bc) fucane, 7-chloro-6-methyl 3-diethylaminofluorane, 3-diethylamino-benzo (b) fluoro, 3- (4-diethylamino-2-ethoxy) -3- (2-methyl-1-ethylindol-3-yl) phthalide, 3- (4 -diylamino-2-butoxy) -3- (2-methyl-1-ethylindol-3-yl) phthalide and 3,7-bis- (diethylamino) -10-benzoylbenzoazoline.

In addition, only the pyridyl blue can be used as the only chromogenic component, since a blue color develops in its reaction with the developer. Of course, this type of chromogenic material has a high resistance to reactivity loss. However, it is preferable to use pyridyl blue in the mixture with another chromogenic component to provide a more saturated color tone; in particular, it is advantageous to partially replace the pyridyl blue with 3,3-bis- (dimethylaminophenyl) -6-dimethylaminophthalate in already known chromogenic materials. A particularly preferred chromogenic material contains not more than 1.3% by weight of 9 226 702 3,7-bis- (dimethylamino) -10-benzoylphenothiazine, not more than 3% by weight of 3,3-bis (dimethylaminophenyl) -6-dimethylamino nophthalide, not more than 2% by weight of 3,3-bis- (1-ethyl-2-methylindol-3-yl) phthalide, not more than 3% by weight of 2-anilino-6Z-diethylamino-3'-methylfluorane and 0.6 to 3% by weight of pyridyl blue. An example of a suitable organic solvent for the pro-chromogenic component may be dialkylphthalenes in which the alkyl groups contain from 4 to 13 carbon atoms, for example dibutyl phthalate, dioctyl phthalate, dinonyl phthalate and ditridecyl phthalate, 2,2,4 trimethyl-1,3-pentadiol diis. U.S. Pat. No. 4,027,065, ethyldiphenylmethane disclosed in U.S. Pat. No. 3,996,405 to alkylbiphenyls, for example, monoisopropylbiphenyl, disclosed in U.S. Pat. No. 3,627,581, alkylbenzenes of 10-14 carbon atoms, for example dodecylbenzene, diaryl ethers for example diphenylether, di (arylalkyl) ether, for example dibenzyl ether and arylalkyl ethers, for example phenylbenzyl ether, liquid dialkyl ethers with at least 8 carbon atoms, liquid alkyl ketones with at least 9 carbon atoms, alkyl or arylalkylbenzoates, for example benzyl benzoate, alkylated naphthalenes and partially hydrogenated terphenyls. Preferred solvents are ethyldiphenylmethane, and 2,2,4-trimethyl-1,3-pentadiol diisobutyrate.

These substantially odorous solvents may be used alone or in admixture with each other. It is also possible to use diluents in order to reduce the cost of the chromogenic material as a result of substituting the more expensive solvent with the more expensive diluent. Of course, this diluent must not chemically react with either the solvent or any other component of the chromogenic material and must be at least partially miscible with the solvent to form a single phase. The diluent is used in such a quantity as to reduce as far as possible the cost associated with the preparation of the chromogenic material, without negatively affecting the solubility of the chromogenic components. Such diluents are already known in the art; a preferred diluent is an oil consisting of mixtures of saturated aliphatic hydrocarbons with a distillation temperature in the range of 160 to 290 ° C.

Encapsulation of the solution of chromogenic components into micro-capsules can be carried out in a known manner, for example by using gelatin as described in U.S. Pat. Nos. 2,800,457 and 3,041,289, or by the use of urea-formaldehyde resin as disclosed in U.S. Pat. 140, 4,087,376 and 4,089,802 or using various melamine-formaldehyde resins described in U.S. Pat. No. 4,100,103. Developers which can be used in combination with the chromogenic material of the invention are known; for example, oily soluble metal salts of phenol formaldehyde - 11,226,702 novolak resins of the type described in U.S. Pat. Nos. 3,672,935, 3,732,120 and 3,737,410. Zinc-modified, phenol-formaldehyde resin is preferred. for example, zinc sulfate of p-octylphenol formaldehyde resin or zinc sulfate of p-phenylphenol formaldehyde resin.

As already mentioned, it is possible to use the chromogenic material according to the invention in a pressure sensitive recording material. The production of these pressure sensitive recording materials is described, for example, in U.S. Patents 3,637,581, 3,775,424 and 3853,869. examples of a particular embodiment in which all said parts are parts by weight. Example 1 Preparation of pyridyl blue 58 g (0.188 mole) of a mixture of (1-ethyl-2-methylindol-3-yl) -3-carboxypyridin-2-yl) ketone and its isomer is stirred at 60-65 ° C for 2 hours. with 35.3 g (0.188 mol) of N, N-di-12,226,702 ethyl-m-phenetidine and 250 ml of acetic anhydride. The reaction mixture is poured into 500 ml of water and the acetic anhydride is hydrolyzed to slowly add 450 ml of a 29% ammonium hydroxide solution. The mixture is stirred for 2 hours and the resulting solid is filtered off and washed with water, 200 ml of 40% methanol in water and 50 ml of petroleum ether boiling in the range of 60 to 110 ° C. The solid obtained is dried to a stable weight in a drying oven at 75 ° C to give 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) 9-1-2-ethoxyphenyl) -5,7-dihydro-furo [3,4-b] pyridin-7-one.

Mp 134-137 ° C. Example 2

A number of chromogenic component solutions were prepared by mixing the following components in the indicated amounts. what what - 13 - 226 702 'φ CM CM Λ κ CO Ρ rd 1 1 1 ο ο

CO Η

Components Chromogenic Component Solution \ t

CM Ό Ό

M β

P «3

O β

P § XS '---- * Ή

P

CQ

> N

Β CM CM CM · • ΡΊ d d d d d d d d d d d d d.. 1 o co CM CM CM 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 m | rd rd 1 1 o o o co p i - 1 · <* rd P p- «h m P rd 1 1 1 what co 1

CM Ρ

CO P rd * »9 *« »· * m P rd 1 1 1 co OO xt-

WHAT

CM Η

xr · rd P XJ r »« Ο ** «* CO rd rd I 1 1 CO 00 O

CM CO

AND

o »

x — X rd £ Φ

<P

oβ • Hβ ¢ 0 -rPP P £ 3

P <H Š β • H -rtΌ

AND

P

Ό β • rd rd £

P Φ a

AND

CM

AND

P

• P

X> P

1 S 8 8. L l β β

P Φ -p-rl '• xpI β® P • rl <HX> x- »I Pco> s» Ico what co

I o β • rl a

WHAT

P £

P Φ

• H Ό

I 'βco «5I βo oβ β

L l — HP HP HP I I I I I I I I I I I I I I I I I I I I

J ο J J J J £ £ J J J J J J J J J J J J J J J J J J

Ό W

I CM

WHAT

»CM CM CM ΛΟ ΛΟ ΛΟ CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM Η Ό

ΓΟ ο β Η and φ Ρ Ρ φ • rl * ΰ

AND

WHAT

I Ρ £ Ρ φ a

AND

D D D D D D D D D D D D D D D Η Η Η Η D D D D D D D D D D D D D D Η η η η η η η η η η η η η η η η η η η η η η η η

CM

Table

CM 00 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM 1 CM M- rd rd • t tg i rd rd o o • m c-> o rd Φ x-> m &amp; CM- X CM * * * * * t t t t t t t * * t t t t ~ ti ti r r r r r r r r r r rd 1 O o <a0 P mt> oo rd dao Λ ti XJ rd CM 00 CM ou Ή r * • 4 ·> 5> rd CM rd 1 O o Λ4 P m r- o CO rd P> • = t CM H r * * 4 ·> NO m rd 1 O om P ~ rd • M- rd rd σ ** * M | m rd rd 1 1 X rd 1 1 O &amp;> x “xma rd ti 1 O &amp;> • rd o P σ rd ti« 3 íd S • d rd and IfVrd OP φ rd P ti D rd 00 • rd SO and 1 i? N 5 5 P P P P P P P P P P P P P 5 5 5 5 τ τ τ τ τ τ τ τ τ P P ti &amp; a «« «d Ό Ό Ό Ό Ό 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 CO CO CO CO φ ø> <+ d Φ rd • 3 £ CO P rd <P x> • rd ti &amp; R • rd rd rd rd ti Ό o (X X> P 1 $ X) a ti m a co t> »1 p rd rd o fc» H »1 '' <i xj P M ΓΟΌ com cm a 3 W 226 702 45 Example 3 226 702 Manufacture of microcapsulated chromogenic material

Each of the solutions of chromogenic components 1 to 16 was encapsulated in microcapsules as described in U.S. Pat. No. 4,0011,40. Briefly, this procedure can be described as follows. 180 parts of the chromogenic solution are emulsified in a mixture of 35 parts of a 10% solution of a copolymer / acid anhydride (maleic having a molecular weight of 75,000 to 90,000 in water, 32 parts of a 20% solution of copolymer | maleic anhydride of 5,000 to 7,000 in water, 133 parts of water, 10 parts of urea and 1 part of resorcinol and the pH of the mixture obtained are adjusted to 3.5 · After the emulsification, 29 parts of 37% formaldehyde are added and the mixture is placed in a 55 ° C water bath with stirring. - the water bath is cooled to ambient temperature while stirring the mixture Example 4 Production of a microcapsule slurry

Each of the microcapsule-encapsulated chromogenic component solutions is formulated into a coating slurry using 16,226,702 of the following amounts of the individual components.

Table 3

Ingredient Nino (s) (dry matter) Dry matter (parts by weight) Chromogenic material 80 40 Granular wheat starch 10 10 Etherified maize starch as binder 40 4 Water 100 - Example 5 Production of donor leaves

Each of the chromogenic materials 1 to 16 is coated onto a sheet of paper in the form of a slurry and the layer thus obtained is heat-dried. - 1? - 226 702 Example 6

A test to determine the loss of reactivity of a donor sheet by light

Each of the chromogenic materials 1 to 16 is subjected to a plurality of features on a donor and acceptor sheet assembly (the acceptor sheet is coated with zinc-modified phenolic resin as described in U.S. Pat. Nos. 3,732,120 and 3,737,410) The naacceptor sheet produces a copy of the set of characters and the intensity of the color of the IC copy characters is determined using an opacimeter.

It is evident that the intensity of the color of the copy features is proportional to the color formation by the reactions between the chromogenic components and the product and is limited by the reactivity of the chromogenic components.

For the purpose of this assay, the color intensity of copyIK is defined as the ratio of the reflectance of the image part (printed part) to the non-image part reflectance (unprinted part) multiplied by 100. Thus, the high intensity of the thus-defined IC copy color signifies low color formation in the chromogenic reaction. on the contrary, the low value of IK means high formation of color by the reaction.

The test is performed both before the donor-18,264,702 sheet is exposed to fluorescent light and after the donor sheet is exposed to the light for 1 hour and 2 hours. In all cases, the intensity of the staining was measured 20 minutes after the copy was printed.

Fluorescence light irradiation was carried out in a box containing a panel of 18 13 W-fluorescent lamps 53.3 cm long, giving white light. Fluorescent lamps were mounted vertically on 2.5 cm washers. The leaves were placed 2.5 to 3.8 cm from the fluorescent tubes. The results obtained are shown in the following table.

Table 4

Donor lists chromogenic material # Initial IK Changed by exposure to leaf 1 hour donor-for: 2 hours 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

I - 19-226 702

Table 4 (continued) 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

The loss of donor leaf reactivity is, of course, dependent on the time of exposure of the donor leaves to light.

The loss of donor leaf reactivity, which is still to be accepted, depends, of course, on the length of exposure of those tolls to light. At exposure for 2 hours, a decrease of more than 26 units is unacceptably high. This means that the chromogenic materials 1, 2, 4, 5, 6 and 7 which contain dodecylphenol and chromogenic materials 11 *, 1: 2, 13, 15 and 16, which contain sufficient pyridyl blue, have received a sufficiently low loss of reactivity. Control materials 3, 8, 9 and 14 and material 10 that contain too few pyridyl blue have an unacceptably high drop in donor leaf reactivity. Example 7 226 702 Manufacture of chromogenic material

Additional chromogenic component solutions were prepared by mixing the following components in the indicated amounts.

Table 5

Component Quantity (parts by weight) Pyridyl blue phenyl 3,3 ~ bis- (dimethylamind) -6 'dimethylaminophthalid 2 2 3,3' bis- (l 'ethyl' 2-methyl-indol-3-yl) phthalide 1 , 2 Alkylbenzene with 10 to 15 carbon atoms in the alkyl moiety 182 E thyldiphenylcarbonyl Di-n-hexyl ketone 6

In addition, each of the solutions contains 6 parts of one of the following phenols: - 21

Table 6

Chromogenic Component Solution No. 226 702

Phenol used 17 octylphenol 18 dodecylphenol 19 cumylphenol 20 styrenic phenol 21 4,4-methylene-bis- (2-tert-butyl-6-methylphenol) 22 2,4,6-tri tert-butylphenol 23 2,6-di- tert.butylphenol Example 8 Production of chromogenic material encapsulated in microcapsules

Each of the solutions of chromogenic components 17 to 23 was encapsulated in microcapsules as described in U.S. Pat. No. 3,103,103. Briefly, this procedure can be described as follows. 200 parts of the chromogenic component solution is emulsified θ 'in a mixture of 35 parts of a 10% baleic acid copolymer / dnhydride solution with a molecular weight of 75,000 to 90,000 - 22,226,702 in water and 140 parts of water with a pH of 3.7. parts of a 20% maleic acid copolymer / anhydride solution having a molecular weight of 5,000 to 7,000 in water and 30 parts of water, the pH of which was adjusted to 4 and 30 parts of methylolmelaminated resin were added thereto. The mixture was then added to the above emulsion and the resulting mixture was placed in a water bath at 55 ° C with stirring. After 2 hours, the water bath was allowed to cool to room temperature while stirring. Example 9 Production of Donor Sheets

Each of the encapsulated solutions of the reactants 17 to 23 is formulated into a coating slurry using the materials and process of Example 4. Each of the thus obtained materials 17 to 23 is applied to a sheet of paper as described in Example 5. Example 10

Test to determine the loss of reactivity of a donor sheet by light effect - 23 - 226 702

The donor sheets containing materials 17 to 23 are subjected to the test described in Example 6. The results are shown in the following table.

Table 7

Donor sheet by schromogenic material <* Initial IK Change in IK leaflet 1 hour exposure to donor-light for 2 hours 17 41 -2 -7 18 42 -4 -7 19 42 -5 -11 20 36 -7 -14 21 38 Using the same criteria for acceptance of individual recording materials as in Example 6, it is possible to consider sheets containing chromogenic materials 17, 18, 1920 and 23 to be unambiguously acceptable. Sheets containing chromogenic materials 21 and 22 containing phenol without reactive binding are unacceptable. Example 11 228 702 Production of chromogenic materials

Other chromogenic component solutions were made by mixing the following components in the indicated amounts. - 2b - 226 702 χυ

Solution of ohromogenic components

CO <0 44 β X> £ 0

EH β and o a and o

W σ »

CI what

CM c ~

CM ir \ t

CM

Tt

CM

CM **

OJ CM i — I

CM

CM CM r — I

OJ *

CM CM H

O

00 O O

i-I-r-1 I-I

ABOUT CO

I I CM I

O σ> o

r-i I r - I I r - | <x r4 · * o i O i m rH Η 1 1 i — 1 o- 1 1 1

CM

CM CM H

O

O

Η I CM

CM

CM CM H

O

About CM | | | | • Η 44 | 1 1 Ή Ή m Φ Φ ι — 1 | 1 and a-H β CO rš 1 • Η 43 3 1 O | JJ Ό Ό m ο ο b r-1 β | γΗ I β • l l ω φ l l l l l l β β β β β β O O • • • • • • a a \ t 2 r ~ 1> N a. * · Ν Η • rl and >> O what β m β and ό 1 X? r — 1 r — 1 · φ>-CO-H CM S Ν χ> <0 β r — 1 H Φ 2 β 1 C0> l cfl rd l l Ρ β Ό í γ γ γ 1 Η Ρ Ρ Ό Ό Ό <1 <<t t t t t t t t t t t t ο X) Η Ρ Ρ Η 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Ν Ν Ν Ν Ν φ φ β β O 1 H 1 · Η • rl o β Χ> Ο. Ο Ο r r r r r s r r r r r r r r r r r r r r r r r r r r r r l l l ~ R J 4 4 i Xi i i · i i i i i i i i i i i i i Λ Λ Λ Λ Λ Λ Λ Λ Λ 1 b β 5? «2 Ρ Ρ >> ** r4 'Ή Η φ 0ΊΌ O">> 5 CM P «4> 26 - 26 - Example 12 226 702 Production of donor sheets

Each of the solutions of chromogenic components 24-29 was encapsulated in the microcapsules as in Example 3. Each microcapsule thus obtained was formulated on a slurry using the materials and process of Example 4. Each of the coating slurries thus obtained was coated with a sheet of paper as described in Example 3. 5 »Example 13

Test to determine the loss of reactivity of a donor sheet by light effect. The donor sheets obtained above were subjected to the test described in Example 6. The results obtained are shown in the following table.

Table 9

Immersion Sheet Initial with Chromogenic IK Material no

Change of IK after exposure of donor leaf to light for 1 hour 2 hours 24 43 -8 -13 - 27 -

Table 9 (continued) 25 43 -8 -14 26 39 -13 -34 27 47 0 -3 28 39 -5 -11 29 46 -4 -6

Chromogenic material donor sheets 24, 25 and -28, which contain pyridyl blue, have a great resistance to reactivity loss. Chromogenic materials 27 and 29, containing a combination of pyridyl blue adodecylphenol, even have excellent resistance to loss of reactivity. The substance-free control chromogenic material 26 to increase the reactivity resistance is unsatisfactory. Example 14 Production of chromogenic materials

Additional chromogenic component solutions were prepared by mixing the following components in the indicated amounts. -28 -

Table 10 226 702

Components Chromogenic Component Solution No. 30 31 32 Quantity (weight: C) fyridyl blue 91.8 91.8 - 3.3-bis- (dimethylaminophenyl) -6-dimethylaminophthalide 21.6 21.6 91,8 3,3-bis- (1-ethyl-2-methylindole-3-thiyl) -phthalide 27 27 14,8 2 z-anilino-6'-di-ethylamino-3-one- thylfluorane 16,2 16,2 29,7 2,3,4-trimethyl-1,3-pentanediol diisobutyrate 3495,6 3509,1 Oil formed by a mixture of saturated aliphatic hydrocarbons with distillation ° C 1747 3146 1754,6 Dibutyl phthalate - 2097,4 - Example 15 Production of micro-encapsulated chromogenic materials

Each of the solutions of chromogenic components 30 to 32 was encapsulated in microcapsules by the method of Example 8. Briefly, this procedure can be described as follows. 5400 parts of the chromogenic component solution are emulsified in a mixture of 1000 parts of a 10% solution of a copolymer of a maleic acid copolymer having a molecular weight of 75,000 to 90,000 in water and 5600 parts of water after adjusting the pH to 3.7. The emulsion obtained is then adjusted to a value of 4. A mixture of 1000 parts of a 10% solution of a maleic anhydride copolymer having a molecular weight of 5,000 to 7,000 in water, 1000 parts of water and 1,000 parts of methylollaminated resin is further prepared. The two mixtures were mixed and the resulting mixture was heated to 55 ° C for 2 hours. After this time, the mixture was allowed to cool to ambient temperature with stirring. Example 16 Production of a microcapsule slurry

Each of the encapsulated solutions of chromogenic components 30 to 32 is formulated into a coating slurry using the materials described in the following table. - 30 -

Table 11 226 702

Component Quantity (parts by weight) Chromogenic material 70,40 Granular wheat starch 21,10 Etherified maize starch as a bite 4,25 Polyvinyl alcohol as a binder 4,25

Sufficient water is added to the mixture to provide a coating slurry of 17.4% solids. Example 17 Production of Donor Sheets

Each of the coating slurries containing chromogenic materials 30 to 32 is applied to a sheet of paper and then dried. Example 18

A test to determine the loss of reactivity of a donor sheet by light

Immersion sheets containing chromogenic materials - 31 226 702 30 to 32 were subjected to the test described in Example 6. The results are shown in the following table.

Table 12

Donor lists chromogenic material. Initial IK Change of IK after exposure of donor sheet to light for 1 hour 2 hours 30 46 -2 -9 31 47 -1 -3 32 53 -17 -30 = Materials 30 can be considered using the criteria given in Example 6 and 31 with pyridyl blue content are very satisfactory in terms of resistance to loss of reactivity, while control material 32 without pyridyl blue is unsatisfactory.

Claims (8)

OBJECT OF THE INVENTION 226 702 What is claimed is: 1. A chromogenic material consisting of at least two microbial components and at least one solvent bromogenic component comprising 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino) one of the chromogenic components. -2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b-pyridin-7-one and / or 7- (1-ethyl-2-methylindol-3-yl) -7- (4 diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one. Chromogenic material according to claim 1, characterized in that it contains phenol with a free reactive bond. 3. Chromogenic material according to claim 2, characterized in that the phenol with free reactive bond contains phenol with a free ortho or para position. 4. Chromogenic material according to claim 2, characterized in that it contains, as free reactive phenol, dodecylphenol, p1,3,3-tetramethylbutylphenol, 2,4-di-tert-butylphenol, p-cumylphenol or styrene-substituted phenol. 5 · Chromogenic material according to Claims 2 to 4, characterized in that it contains phenol with a free reactive bond in an amount of - 32% - 1 to 7% by weight. 226 702 6. A material according to claim 5, wherein the free reactive phenol is present in an amount of 2 to 5% by weight. 7. Chromogenic material according to claims 1 to 6, characterized in that it contains 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro. - 3,4-bpyridin-7-one and / or 7- (1-ethyl-2-methylindol-3-yl) -7- (8-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [alpha] 3,4-bpyridin-5-one in an amount of 0.6 to 3% by weight. 8. Chromogenic material according to claim 1, characterized in that it is contained in microcapsules.