IE49346B1 - Chromogenic composition - Google Patents

Description

This invention relates to a chromogenic composition a process for its preparation, a microencapsulated chromogenic composition, and pressure-sensitive record material containing the composition.

The colour forming systems used in pressure-sensitive record material generally employ a substantially colourless chromogenic material, a colour developer capable of reacting with the chromogenic material to generate a colour and a solvent in vzhich the colour forming reaction can take place. The reactive components of the colour forming system are kept apart until the time of use and this is normally achieved bymicroencapsulating a chromogenic composition comprising a solvent solution of the chromogenic material. At the time of use, the application of pressure causes rupture of those microcapsules that· are. subject to such pressure and consequential release of the chromogenic solution. This then allows both colour forming components to be brought into reactive contact and to generate a coloured image which exactly corresponds to the pattern of applied pressure. In this way, pressure-sensitive record material can be used to provide copies without the need for any carbon paper.

In a self-contained record system, the record material comprises a sheet having a coatiDg of the microencapsulated chromogenic solution in admixture with the colour developer. Alternatively, the microencapsulated chromogenic solution and the colour developer may be dispersed within the sheet itself. > 48346 In a transfer record system, at least two record materials are employed. One comprises a sheet having a coating of microencapsulated chromogenic solution (the CB sheet) and the other comprises a sheet have a coating of a colour developer (the CF sheet). The sheets are assembled together as a manifold set with their coatings in contiguous relationship so that transfer of the chromogenic solution can take place from the CB sheet to the CF sheet. To provide further copies, the manifold set may additionally include a third record material which comprises a sheet having on one side a coating of the microencapsulated chromogenic solution and on the other side a coating of the colour developer. One or more of these sheets (CFB sheets) are disposed between the CF and the CB sheets in the manifold set with each microcapsule coating in contiguous relationship with a colour developer coating.

Whether a self-contained or a transfer record system is used, one of the important properties of the microencapsulated chromogenic solution is its reactivity, i.e. its ability to produce an image of acceptable intensity on reaction with a colour developer. Generally, most record materials that contain a microencapsulated chromogenic solution show a satisfactory reactivity if they have not been exposed to ambient conditions, including, in particular, light. However, after prolonged exposure to such conditions, the record materials invariably have a much poorer reactivity.

This reduction in reactivity, which is often referred to as CB decline, can moreover be greater if certain solvents or chromogenic materials are used. For example, a chromogenic solution of Crystal Violet Lactone in 2,2,4-triraethy1 1,3-pentanediol di-i-butyrate (TXIB) suffers particularly from the problem of CB decline.

It is an object of the present invention to provide a chromogenic composition suitable for use in pressuresensitive record systems and which does not suffer, at least not to the same extent, from the above-mentioned problem with CB decline.

Id a first aspect, the present invention provides a chromogenic composition which comprises a substantially colourless chromogenic material, an organic solvent for the chromogenic material and a phenol having a free reactive position. In a second aspect, the present invention provides a process for preparing a chromogenic composition which comprises admixing a substantially colourless chromogenic material, an organic solvent for the chromogenic material, and a phenol having a free reactive position.

The use of a phenol having a free reactive position imparts to the chromogenic composition an ability to resist CB decline. In addition, coloured images produced from the composition have excellent fade resistance and hue stability.

Patent Specification No. 25^7^77 of which this application is a divisional, describes and claims a chromogenic composition having improved CB decline resistance comprising pyridyl blue alone or in combination with one or more other substantially colourless chromogenic materials and an organic solvent for the chromogenic materials. 48346 A phenol having a free reactive position includes those which have a free ortho-or para-position. Such phenols are normally substituted by any of a straight or branched alkyl group, an aralkyl group, or an aralkenyl group. Specific examples include dodecylphenol; p-1,1,3,3-tetramethylbutylphenol; 2,4di-t-butylphenol; p-cumylphenol; and styrenated phenol. These phenols are known and can be prepared by conventional processes.

The phenol is preferably used in an amount of from 1 to 7, for example 2 to 5, weight per cent (i.e. parts by weight of phenol per 100 parts of chromogenic composition).

A substantially colourless chromogenic material of use in the present invention includes one or more of 3,7-bis(dimethylamino) -10-benzoyl-phenothiazine (benzoyl leuco methylene blue, BLMB); 3,3-bis (dimethylamino phenyl)-6-dimethylaminophthalide (Crystal Violet Lactone, CVL); 2'-anilino-6'-diethylamino-3'methylfluoran (N102); 3,3-bis (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-ethylaminoxanthene9, 2-(2H) naphthol (1,8-bc) furan; 7-chloro-6-methyl-3-diethyl20 aminofluoran; 3-diethylaminobenzo (b) fluoran; 3-(4-diethylamino-2-ethoxy)-3-(2-methyl-l-ethylindol-3-yl) phthalide, 3(4-diethylamino-2-butoxy)-3-(2-methyl-l-ethylindol-3-yl) phthalide; and 3,7-bis (diethylamino)-10 benzoyl-benzoazine.

A particularly advantageous chromogenic composition includes Pyridyl Blue as the substantially colourless chromogenic material either alone or in combination with one of the above listed chromogenic materials, Pyridyl Blue is 7-(15 ethyl-2-methylindol-3-yl)-7-(4-diethylamino-2-ethoxy-phenyl)5,7-dihydro-furo (3,4-b) pyridin-5-one and/or 5-(l-ethyl-2methylindol-3-yl)-5-(4-diethylamino-2-ethoxyphenyl)-5,7dihydrofuro (3,4-b) pyridin-7-one.

Examples of a suitable organic solvent for the chromogenic material include dialkyl phthalates in which the alkyl groups have from 4 to 13 carbon atoms, such as dibutyl, octyl, dinonyl and ditridecyl phthalates; 2,2,4-trimethyl1,3-pentanediol di-i-butyrate (TXIB, U.S. patent 4 027 065); ethyldiphenylmethane (U.S. patent 3 996 405); alkyl biphenyls, such as mono-i-propylbiphenyl (U.S. patent 627 581); C^q-C^ alkyl benzenes, such as dodecylbenzene; diaryl ethers, such as diphenyl ether, di(aralkyl) ether such as dibenzyl ether, and aryl aralkyl ethers, such as phenyl benzyl ether; liquid dialkyl ethers having at least eight carbon atoms; liquid alkyl ketones having at least nine r-arhm atoms; alkyl or aralkyl benzoates, such as benzyl benzoate 48346 alkylated naphthalenes; and partially hydrogenated terphenyls. Preferred solvents include ethyldiphenylmethane and 2,2,4-trimethyl-l,3-pentanediol di-i-butyrate.

These solvents, which are all substantially odourless, may be used alone or in combination. They may also be used with a diluent in order to reduce the cost of the chromogenic composition. Of course, the diluent must not be chemically reactive with either the solvent or any other component of the composition and must be at least partially miscible with the solvent so as to give a single phase. The diluent is used in an amount sufficient to achieve a cost benefit but without impairing the solubility of the chromogenic material. Diluents are already known in the art and a preferred example thereof is Magnaflux oil, which is a mixture of saturated aliphatic hydrocarbon oils having a distillation temperature of 320 to 550°F (16O-288°C).

The present invention also provides a microencapsulated chromogenic composition, as hereinbefore defined. Microencapsulation of the composition can be carried out by processes known in the art, for example, by using gelatin as described in U.S. patents 2 800 457 and 041 289, by using an urea-formaldehyde resin as disclosed in U.S. patents 4 001 140, 4 087 376 and 089 802, and by using various melamine-formaldehyde resins as disclosed in U.S. patent 4 100 103.

Colour developers suitable for use with the composition of the present invention are known in the art, and include oil-soluble metal salts of phenol-formaldehyde novolak resins of the type described in U.S. patents 48346 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, such as the zinc salt of a p-octylphenol-fcrmaldehyde resin or the zinc salt of a p-phenylphenol formaldehyde resin.

The present invention also provides pressure-sensitive record material which contains a chromogenic composition, as hereinbefore defined.

Coating formulations and processes for the preparation of 10 pressure-sensitive record material are generally known -in the art, for example U.S. patents 3 627 581, 3775 424 and 3 853 869.

The present invention will now be described with reference to a number of examples thereof, in which all parts are by weight.

Example 1-Preparation of Chromogenic Compositions A number of chromogenic solutions were prepared by admixing the following components in the parts indicated: ω to I *c C5 5 w to > & 0 Φ rt μ- μ-> Φ & r* 3* 31 £. 3 Φ 3* *< * *< 0 ft P r·· H l·-» 3 CL P w Φ J-»· rt· 1 Ό Λ Φ Γ+ 3* V Φ << I 3 O O Z M n P 3* P* 1 3 <3 c* 3* l-J CL r Φ 0 Φ O 0 5 to t—· >·*· 0 «< P CR H* μ·» a 3 so H· Φ 0 CL σ> i p 3· 3 l—1 Φ 3 K 3 Φ H· 3 0 ►j l·’ Φ >— 0 0) » to a rt sr 0 σ 0 ! 3 Φ b b 4* << φ to η h co Η M A , G-dimethyl-3-ethylaminoxanthene-9,2-(2H) naphtho (1,8-bc)iuran 4b φ • co to 0) b b A Η I-1 CO H W 4* Ito o 00 to P ! H ω o 4b 1 H H 4b ί- Ο 05 0 (—1 ω O Η» 1 « i co o b O to to 1 tfcw rs P I* l-l 0 05 O ω O H Η· 1 > i CO I CP b b b to σ' Μ 1 IP H* 05 ω ω p O p Η 1 • | b b O to Ζ\ ft to t th· I® H 05 w ω O p P Ϊ M |M b b 0 1 to to 4b η t—* ω Μ M A TABLE I» Example 2- Preparation of Microencapsulated Chromogenic Compositions Each of the chromogenic solutions 1 to 8 was microencapsulated according to the procedure disclosed in U.S. patent 4 001 140. Briefly, this was as follows : 180 parts of the chromogenic solution was emulsified in a mixture of 35 parts of 10% ΞΦ. (Trade Mark) (ethylene-maleic anhydride copolymer with a molecular weight range of 75,000 to 90,000, supplied by Monsanto Chemical Co.) in water, 32 parts of 20% EMA 1103 (ethylene-maleic anhydride copolymer with a molecular weight range of 5000 to 7000, supplied by Monsanto Chemical Co.) in water, 133 parts of water, 10 parts of urea and 1 part of resorcinol, adjusted to pH 3.5. Following emulsification, 29 parts of 37% formaldehyde was added and the mixture was placed -in a. 55 C water bath with stirring. After two hours, the temperature of the water bath was allowed to equilibrate with the ambient temperature while stirring was maintained.

Example 3- Preparation of Microcapsule Coating Formulations Each of the microcapsule batches 1 to 8 was made up into a coating formulation using the materials and parts listed below : 49348 Parts Wet Parts Dry Capsule batch Wheat Starch Granules *Penford 230, 10% Water 100 ♦Etberified corn starch binder made by Penick and Ford Ltd.

Example 4- Preparation oi CB Record Materials Each oi the coating formulations 1 to 8 were dispersed, applied to a paper base and drawn down with a No, 12 wire-round coating rod and the coatings dried with a heat gun.

Example 5- CB Decline Comparative Tests Each of the CB record materials 1 to 8 were subjected to the Typewriter Intensity (TI) Test in which a standard pattern is typed on a manifold set comprising a CF and a.CB sheet, (the CF sheet in the present tests being coated with a zinc-modified phenolic resin as disclosed in D.S. patents 3 732 120 and 3 737 410). A coloured print image corresponding to the pattern is thus produced on the CF sheet and the intensity of the image is determined with the aid of an opacimeter.

The intensity is a measure of colour development and is the ratio of the reflectance of the print image to that of the unimaged area (Σ/Ιρ) expressed as a percentage.

A high value indicates little colour development and a low value indicates high colour development.

Typewriter Intensity (TI) Tests were conducted before exposure of the CB sheet to fluorescent light irradiation and after one and two hours exposure of the CB sheet to such irradiation. In all cases, the intensity measurements were taken at 20 minutes after imaging.

The device for the fluorescent light tests comprised a light box containing a bank of IS daylight fluorescent lamp (21 inches (53.3cm) long, 13 nominal lamp watts) vertically mounted on 1 inch (2.5 cm) central supports. ihe CB lu sheets were placed 1 to the lamps.

The results obtained for are presented below : CB Record Initial Material No. TI 41 43 36 4 41 38 38 · 38 L.5 inches (2.5 to 3.8cm) from the eight CB record materials Change in TI after Light Exposure of CB Coatings 1 Hr. Exposure 2 Hr. Exposure - 2 - 6 - 3 - 7 -13 -34 - 6 -15 - 5 -13 - 8 -15 - 5 -10 -18 -32 . 49346 The amount of CB decline which is acceptable is of course dependent upon the duration of light exposure of the CB.

For the 2 hour exposure a loss of more than about 26 5 units is unacceptably high. Thus, record materials 1, 2, 4, 5, 6 and 7 which contained dodecylphenol produced a sufficiently low amount of CB decline to be acceptable. Record materials 3 and 8 which were controls containing no material added to provide CB decline resistance both showed an unacceptably high amount of CB decline.

Example 6- Preparation of Chromogenic Compositions Additional chromogenic solutions were prepared by admixing the following components in the parts indicated : Pyridyl blue _ 2.0 CVL 2.0 Indolyl red 1.2 Alkylate 215 182.0 Ethyldiphenylmethane 6.0 Di-n-hexylketone 6.0 in addition, each of the solutions contained 6.0 parts of one of the following phenols : octyl phenol dodecyl phenol cumyl phenol styrenated phenol 4, 4-methylene-bis(2-tertbutyl6-methyl phenol) 2, 4, 6-tri-tertbutyl phenol 2, 6-di-tertbutyl phenol Example 7- Preparation of Microencapsulated Chromogenic Composition Each of the chromogenic solutions 9 to 15 was microencapsulated according to the procedure disclosed in the U.S. patent 4 100 103. The specific procedure was as follows : 200 parts of the chromogenic solution was emulsified in a mixture of 35 parts of 10% EMA 31 in water and 140 parts of water, adjusted to pH 3.7. A mixture of 32 parts of 20% EMA 1103 and 30 Darts of.water, was adjusted to pH 4.0 and 30 parts of itesimsne (Trade Mark) 714 (methylated methylol melamine resin produced by Monsanto Chemical Co.) was added thereto. This mixture was added to the emulsion and the total mixture was placed in a 55°C. water bath with stirring. After two hours, the temperature of the water bath was allowed to equilibrate 25 with the ambient temperature while stirring was maintained. 4-834 6 Example 8- Preparation of CB Record Materials Each of the microcapsule batches 9 to 15 was made up into a coating formulation using the materials and procedure of example 3.

Each cf the coating formulations 9 to 15 were coated on a paper base as described in example 4.

Example 9- CB Decline Comparative Tests The CB record materials 9 to 15 were subjected to the same tests in the same manner as described in example 5. *0 The results obtained are presented below : CB Record Material No. Initial TI Change in TI after Light Exposure of CB Coatings 1 Hr. Exposure 2 Hr. Exposure 9 41 - 2 - 7 10 42 - 4 - 7 11 42 - 5 -11 . 12 36 - 7 -14 13 38 -23 -34 14 39 -20 -27 15 40 - 3 -13 . 49346 Using the guidelines of acceptability set out in example 5, record materials 9, 10, 11, 12 and 15 are all clearly satisfactory. The record materials 13 and 14 contained a phenol with no reactive position and are clearly unsatisfactory.

Example 10 - Preparation of Chrorogenic Compositions Further chromogenic solutions were prepared by admixing the following components in the parts indicated : 16 iZ 18 19 20 21 10 Pyridyl Blue 2.0 2.0 — 2.0 2.0 2.0 CVL 2.0 2.0 3.4 2.0 2.0 2.0 Indolyl Red 1.2 1.2 1.1 1.2 1.2 1.2 N-102 — — 1.1 — — — Other 15 Chromogenic material — 1.0(d) ·--- — 1.0(e) --- Alkylate 215 200.0 200.0 130.0 190.0 180.0 180.0 ethyldiphenyl methane — — 70.0 — — — 20 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) methylmyristate Example 11 - Preparation of CB Record Materials Each of the chromogenic solutions 16 to 21 was microencapsulated according to the procedure of example 2.

Each of the microcapsule batches 16 to 21 was made up 5 into a coating formulation using the materials and procedure of example 3.

Each of the coating formulations 16 to 21 was coated on a paper base as described in example 4.

Example 12 - CB Decline Comparative' Tests The CB record materials 16 to 21 were subjected to the same tests in the same manner as described in example 5.

The results obtained are presented below : CB Record Initial Change in TI after Light Material No. TI Exposure of CB Coatings 1 Hr. Exposure 2 Hr. Exposure 16 43 - 8 - 13 17 43 - 8 - 14 18 39 -13 - 34 19 47 0 3 20 39 - 5 - ii 21 46 - 4 - 6 Record materials 16, 17 and 20, which contain Pyridyl Blue, all show very good CB decline resistance. Record materials 19 and 21 which contain both Pyridyl Blue and dodecyl phenol show excellent CB decline resistance. Record material 18 is a control containing no material for resisting CB decline and is unsatisfactory.

Exairpi e 13 Pyridyl blue- which is used in examples 6 and 10 is a mixture of the isomers - 7-( l-ethyl-2-methylindol-3-y 1.)7-( 4-dic-thyIamino-2-ethoxy-phenyl )-5,7-dihydrofuro(3,4-b) pyridin-5-one and 5-(l-ethyl-2-methyl-indol-3-yl)-5(4-diethy1 amino-2-ethoxyphenyl)-5,7,dihydrofuro (3,4-b) pyridin-7-one and can be prepared as follows : Q-uindinic anhydride (0.21 mol) and l-ethyl-2-methylindole (0.33 mol) were mixed together in a reaction flask at 65-70°C for 3 hours. The reaction mixture was then cooled and washed with benzene (or chlorobenzene) to provide (l-ethyl-2-methylindol-3-yl)(3-carboxypyridin-2yl) ketone and its isomer (0.19 mol). (l-Ethyl-2-metbylindol-3-yl)(3-carboxypyridin-2-yl) ketone and its isomer (together 58.Og; 0.188 mol) were stirred for two hours at 6O-65°C with N, N-diethyl-mphenetidine (35.3g; 0.188 mol) and acetic anhydride (250ml). The reaction mixture was poured into water (500ml) and the acetic anhydride hydrolyzed by slowly adding 29% ammonium hydroxide (450ml). After stirring for two hours, the resulting solid was filtered and washed with water, 40% methanol/water (200ml) and 48346 petroleum ether (b.p. 6O-11O°C; 50ml). The solid was then dried to constant weight in an oven at 75°C to give a mixture (9:1 respectively) of 7-(l-etbyl-2methylindol-3-y1)-7-(4-diethylamino-2-ethoxy-phenyl)-5, 7-dihydrofuro (3,4-b) pyridin-5-one and 5-(l-ethyl-2methyl-indol-3-y1)-5-(4-diethylamino-2-ethoxyphenyl)-5, 7-dihydroiuro (3,4-b)pyridin-7- one (80.5g, 90%, m.p.'*' 134.137°C).

Claims (12)

1. CLAIMS:1. A chromogenic composition which comprises a substantially colourless chromogenic material, an organic solvent for the chromogenic material and a phenol having a free reactive position.

2. A chromogenic composition which comprises a substantially colourless chromogenic material, an organic solvent for the chromogenic material and a phenol having a free reactive position wherein the chromogenic material is Pyridyl Blue alone or in combination with one or more other chromogenic materials .

3. A chromogenic composition according to claim 2, wherein the phenol is dodecylphenol, p-1, 1, 3, 3-tetramethylbutylphenol, 2, 4-di-t-butyIphenol, p-cumyIphenol, or styrenated phenol.

4. A chromogenic composition according to any one of the preceding claims wherein the phenol is used in an amount of from l’to 7 weight percent.

5. A chromogenic composition according to claim 4, wherein from 2 to 5 weight percent is used.

6. A chromogenic composition according to any one of the preceding claims, wherein the chromogenic material includes 3, 3-bis (dimethylaminophenyl)-6-dimethylaminophthalide, 3,3-bis (l-ethyl-2-methylindol3-yl) phthalide, and 2‘-anilino-6'-diethylamino-3*methylfluoran.

7. A chromogenic composition according to any one of the preceding claims, wherein the organic solvent is ethyldiphenylmethane or 2, 2, 4-triniethyl-l, 3pentanediol di-i-butyrate. 5 8. A process fcr preparing a chromogenic composition, as defined in any one of claims 1 to 7, which comprises admixing a substantially colourless chromogenic material, an organic solvent for the chromogenic material and a phenol having a free reactive position.

8. 10 6. A microencapsulated chromogenic composition in which the chromogenic composition is as defined in any one of claims Ϊ to 7. 10. Pressure-sensitive record material which contains a chromogenic composition as defined in any one of 15 claims 1 to 7 and 9.

9. 11. A chromogenic composition substantially as described hereinbefore with reference to any one of runs 1, 2, 4, 5, 6 and 7 of example 1, runs 9, 10, 11, 12 and 15 of example 6 and. runs 19 and 21 of example 10.

10. 12. A process for preparing a chromogenic composition substantiall5 ; as described hereinbefore with reference to an;,· one of runs 1, 2, 4, 5, 6 and 7 of example 1, runs 9, 10, 11, 12 and 15 of example 6 and runs 19 and 21 of example 10.

11. 13. A microencapsulated chromogenic composition substantially as described hereinbefore with reference to any one of runs 1, 2, 4, 5, 6 and 7 of example 2, runs 9, 10, 11, 12 and 15 of example 7 and runs 19 and 21 of example 11.

12. 14. Pressure-sensitive record material substantially as described hereinbefore with reference to any one of runs 1, 2, 4, 5, 6 and 7 of example 4, runs 9, 10, 11, 12 and 15 Of example 8 and runs 19 and 21 of example 11.