FI73174B - CHROMOGENT MATERIAL SAMT DESS ANVAENDNING. - Google Patents

Description

· * § *** · I ANNOUNCEMENT Π \ ΛΠΛ • SF® CB] (11) utläggningsskrift 0 ^ • C Pate /: tti EyCnn-itty (4o) Γ - 1 η) _, T, ~> 1 1 j. 1, '- \ pn n -, n ry (51) Kv.lk.Vlnt.CI4 B 41 M 5/12 // C 09 D 11/02

SUOMI FINLAND

(Fl) (21) Patent application - Patentansökning 794022 (22) Application date - Ansökningsdag 21.12.79

National Board of Patents and Registration (23) Start date-Giltighetsdag 21.12.79

Patent- och registerstyrelsen (41) Became public-Biivit offentiig 30.06.80 (44) Date of dispatch and of publication. - 2Q n 5 87

Ansökan utlagd och utl.skriften publicerad. '5' '(86) Kv. application - Int. ansökan (32) (33) (31) Claim claimed - Begärd priority 29.12.78 29.12.78, 05.06.79, 05.06.79 USA (US) 000375, 000365, 045769, 045768 (71) Appleton Papers Inc., Delaware, US; P.O.Box 359, Appleton,

Wisconsin, USA (72) Robert Erwin Miller, Appleton, Wisconsin,

Bruce Wilford Brockett, Appleton, Wisconsin,

The present invention relates to a chromogenic substance, to processes for its preparation and to a process for the preparation of chromogenic substances and pressures containing chromogenic substances. Troy Eugene Hoover, Appleton, Wisconsin, USA (74) Jalo Ant-Wuorinen Ab (54) Chromogenic substance and its use -sensitive recording media.

The color formation systems used in pressure sensitive media generally contain a predominantly colorless chromogenic agent, a color developer that reacts with the chorogenic agent to develop color, and also a solvent in which the color formation reaction can occur. The reactive components of the color-forming system are kept separate from each other until use, and this is generally accomplished by microencapsulating a solvent solution of one reactive component, usually a chromogenic agent. At the time of use, the microcapsules, which are exposed to pressure, break, releasing the solvent solution. As a result, both color-forming components come into reactive contact, forming a color trace that exactly matches the pressure pattern. In this way, a pressure-sensitive recording medium can be used to produce copies without carbon paper.

Generally speaking, there are two types of recording systems that use pressure sensitive recording material.

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In one of these, called a self-contained storage system, the recording material comprises a sheet coated with a mixture of a color developer with a microencapsulated solvent solution of a chromogenic agent. Alternatively, the color developer and the microencapsulated chromogenic solution may be dispersed in the sheet itself.

The second type, called a transfer-storage system, uses at least two recording materials. In a conventional and more commonly used transfer-storage system, one recording material comprises a sheet coated with a microencapsulated solution of a chromogenic agent (CB sheet) and the other comprises a sheet coated with a color developer (CF sheet). In an inverse transfer storage system, the color developer, and not the chromogenic agent, is microencapsulated as a solvent solution. Thus, one recording material comprises a sheet coated with a solution of a microencapsulated color developer (CB sheet) and the other comprises a sheet coated with a water-insoluble substantially chemically neutral pigment to which the chromogenic substance is adsorbed. The CB and CF sheets are combined into a series of residues so that the coatings are in contact with each other, whereby the transfer of the solvent solution from the CB sheet to the CF sheet can take place.

To obtain additional copies, the embossing kit may further comprise a third recording material comprising a sheet with a CB coating on one side and a CF coating on the other. One or more of these sheets (CFB sheet) are interposed between the CF and CB sheets in the stacking kits so that each CB coating is against the CF coating.

Various chromogenic substances are normally used in combination to form a trace having certain optical characteristics. One of the most common of these substances is crystal violet lactone (CVL; 3,3-bis- (p-dimethylaminophenyl) -6-dimethylaminophthalide) which has been used in combination with other chromogenic substances to form a blue or black mark. However, the fading resistance of crystal violet lactone is poor, i.e., its ability to resist color deterioration in the formed trace is poor. In addition, if the crystal violet lactone is exposed to ambient conditions, including light, its color-forming reactivity, i.e., its ability to form an imprint of acceptable intensity upon reaction with the color developer, is substantially degraded. This deterioration in reactivity, whether microencapsulated or not, is often referred to as CB impairment in the case of normal transfer media, and may be greater if the substance is used as a chromogenic solution in certain solvents, such as 2,2,4-trimethyl-1,3- in pentanediol di-i-butyrate (TX1B). Despite these drawbacks, however, crystal violet lactone has consistently been widely used due to the lack of a commercially viable alternative.

It is an object of the present invention to provide a chromogenic agent which can be used to replace all or part of the crystal violet lactone and which has improved fade resistance and an improved ability to prevent deterioration of reactivity.

This invention relates to a chromogenic substance consisting essentially of a compound of formula »3 Vs which is 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5, 7-dihydrofuro [3,4-b] pyridin-5-one, optionally as a mixture of formula C2H5 / OC2H5 fo)

Kgyrv with an isomeric compound of C 2 H 5 <O 2 = O CH 3 V * which is 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7 -dihydrofuro [3,4-b] pyridin-7-one.

73174

In addition to the substance according to the invention, which is referred to herein as pyridyl blue, it has improved fading resistance and a better ability to resist a decrease in reactivity, its color-forming ability is rapid and it is able to obtain a blue color with excellent intensity and tone stability.

Its reactivity to carrier paper is also very low. This is important because, when used in a normal transfer system, the fading of the CB sheet, i.e. the color caused by the reaction between the CB paper carrier paper and the non-transferred chromogenic solution, is slight, if not non-existent.

Either of the above isomers can be used as the chromogenic agent, although the pyridin-5-one isomer is more useful. However, it is more preferable to use a mixture of isomers in which the pyridin-5-one isomer predominates. This is because the process used to prepare the chromogenic substance produces this type of mixture and the subsequent separation of isomers using known methods is difficult, time consuming and commercially expensive.

The chromogenic substance as defined above can be prepared by a keto acid having the formula

Hc / A

n \ _cooh u is reacted with a compound of formula

B - H

wherein one of A and B is 4-diethylamino-2-ethoxyphenyl and the other is 1-ethyl-2-methylindol-3-yl, in the presence of a dehydrating agent.

A suitable dehydrating agent is an acid anhydride, such as acetic anhydride, and the reaction is preferably carried out at an elevated temperature, such as 65-75 ° C.

When A is 1-ethyl-2-methylindol-3-yl, the keto acid is prepared by reacting quinoline anhydride with 1-ethyl-2-methyl 73174 li-indole and the reaction is generally carried out at a temperature of 60-70 ° C.

When A is 4-diethylamino-2-ethoxyphenyl, the keto acid is prepared by reacting quinoline anhydride with N, N-diethyl-m-phenethidine. The reaction is generally carried out in a solvent in the presence of a catalyst such as aluminum chloride and at a temperature of 35 to 40 ° C.

A is preferably 1-ethyl-2-methylindol-3-yl, since the keto acid can then be prepared without solvent and without catalyst. The two-step process used then further promotes the formation of the pyridin-5-one isomer compared to the two-step process in which A is 4-diethylamino-2-ethoxyphenyl. According to a more preferred method, a mixture can in fact be prepared in which the amount of pyridin-5-one isomer is at least 90%, up to 95% of the total mixture.

According to another method, a chromogenic substance as defined above is prepared by reacting quinoline anhydride, 1-ethyl-2-methylindole and N, N-diethyl-m-phenethidine in the presence of a dehydrating agent such as one of the above.

However, this method is less preferred.

The chromogenic agent of the invention can, of course, be combined with other chromogenic agents to provide a particular hue or color in the resulting trace. It is advantageous to add the chromogenic substance according to the invention to the resulting combination, as it gives the combination the ability to resist the loss of reactivity. Examples of such substances are one or more of the following: 3,7-bis (dimethylamino) -1O-benzoyl-phenothiazine (benzoyl-leukomethylene blue, BLMB) 2'-anilino-6'-diethylanino-3'-methylfluorane (N102) -3, 3-bis (1-ethyl-2-methylindol-3-yl) phthalide (indolyl red); 3,3-bis (1-butyl-2-methylindol-3-yl) phthalide; spiro-7-chloro-2,6-dimethyl-3-etyyliaminoksan-teeni-9,2- (2H) -naftoli- (1,8-bc) furan; 7-chloro-6-methyl-3-dietyyliaminofluoraani; 3-dietyyliaminobentso (b) fluoran; 3- (4-diethylamino-2-ethoxy) -3- (2-methyl-1-ethyl-indole-3-yl) phthalide; 3- (4-diethylamino-2-butoxy) -3- (2-methyl-1-ethyl-indole-3-yl) phthalide; and 3,7-bis- (diethylamino) -10-benzoyl-73174 benzoxazine. In addition, the chromogenic agent of the invention can be used in conjunction with, and instead of, crystal violet lactone.

In a self-contained or normal transfer storage system, the chromogenic agent of the invention is used alone or in combination as a microencapsulated chromogenic solution. Examples of a suitable organic solvent for preparing a chromogenic solution include dialkyl phthalates in which the alkyl groups contain from 4 to 13 carbon atoms, such as dibutyl, dioctyl, dinonyl and ditridecyl phthalates; 2,2,4-trimethyl-1,3-pentanediol di-i-butyrate (TX1B, U.S. Patent 4,072,065); ethyldiphenylmethane (U.S. Patent 3,996,405); alkyl biphenyls such as mono-i-propyl biphenyl (U.S. Patent 3,672,581); C 1 -C 4 alkylbenzenes such as dodecylbenzene; diaryl ethers such as diphenyl ether, di (aralkyl) ether such as dibenzyl ether, and aryl aralkyl ethers such as phenylbenzyl ether; liquid dialkyl ethers having at least 8 carbon atoms, liquid alkyl ketones having at least 9 carbon atoms; alkyl or aralkyl benzoates such as benzyl benzoate; alkylated naphthalenes, and partially hydrogenated terphenyls. Preferred solvents are ethyl diphenylmethane and 2,2,4-trimethyl-1,3-pentanediol di-i-butyrate.

These solvents, all of which are substantially odorless, can be used alone or in combination. They can also be used in combination with a diluent to reduce costs. It is clear that the diluent must not react chemically with the solvent or chromogenic agent and should be at least partially miscible with the solvent to form a single phase. The diluent is used in an amount sufficient to achieve the cost benefit but which does not adversely affect the solubility of the chromogenic agent.

Such diluents are known and a preferred example of this is Magnaflux oil, which is a mixture of saturated aliphatic hydrocarbon oils with a distillation temperature of about 160-290 ° C (3-20-550 ° F).

The amount of the chromogenic substance according to the invention to be used in the chromogenic solution depends, of course, on the particular need, but in general the usable amount is 0.6 to 3% by weight (i.e., 100 parts by weight per 100 parts by weight of the solvent of the chromogenic substance).

Microencapsulation of a chromogenic solution can be performed by known methods, for example, using gelatin as described in U.S. Patent Nos. 2,800,457 and 3,041,289, using urea formaldehyde resin as described in U.S. Patent 4,001,140, 4,087,376 and 4,089,802, and using various melamine-formaldehyde resins as described in U.S. Patent 4,100,103.

Color developers useful with the chromogenic agent of this invention are known and include acid clays and oil-soluble metal salts of phenol-formaldehyde-novolac resins described in U.S. Patent Nos. 3,672,935, 3,732,120 and 3,737,410. A preferred example of a suitable resin is resin a phenol-formaldehyde resin such as a zinc salt of p-octylphenol-formaldehyde resin or a zinc salt of p-phenyl-phenol-formaldehyde resin.

In the reverse transfer system, the chromogenic agent of the invention is not microencapsulated as a chromogenic solution but is adsorbed on a water-insoluble, predominantly chemically neutral pigment, as described in GB 1 337 924. However, a color developer which may be a resin of the above type microencapsulated as a solution. Suitable solvents and encapsulation methods are those described above.

The invention also relates to a pressure-sensitive recording material which, as a component of its color development system, contains a chromogenic substance as defined above.

Coating compositions and methods for making a pressure sensitive recording material are well known, see, for example, GB Patent 1,337,924 and U.S. Patent Nos. 3,627,581, 3,775,424 and 3,853,869.

The following are some examples illustrating the invention, in which all parts are by weight.

Example 1 - Preparation of a chromogenic substance

Quinoline anhydride (0.21 mol) and 1-ethyl-2-methylindole (0.33 mol) were mixed in a reaction flask at 65-70 ° C for 3 hours. The reaction mixture was then cooled and washed with benzene (or chlorobenzene) to prepare (1-ethyl-2-methyl-indol-3-yl) - (3-carboxypyridin-2-yl) -ketone and its isomer (0.19 mol).

73174 (1-Ethyl-2-methyl-indol-3-yl) - (3-carboxypyridin-2-yl) -ketone and its isomer (58.0 g in total; 0.188 mol) were stirred for two hours at 60-65 ° C: with N, N-diethyl-m-phenethidine (35.3 g; 0.188 mol) and acetic anhydride (250 ml). The reaction mixture was poured into water (500 ml) and acetic anhydride was hydrolyzed by slow addition of 29% ammonium hydroxide (450 ml). After stirring for two hours, the resulting solid was filtered and washed with water, 40% methanol / water (200 mL) and petroleum ether (b.p. 60-110 ° C; 50 mL). The solid was then dried to constant weight in an oven at 75 ° C to a mixture (9: 1) of pyridin-5-one and pyridin-7-one (80.5 g; 90%, m.p. 134- 137 ° C).

Example 2 - Preparation of a chromogenic substance

A mixture of (1-ethyl-2-methylindol-3-yl) (3-carboxypyridin-2-yl) ketone and its isomer (total 3.62 g; 0.0117 moles) and N, N- diethyl m-phenethidine (2.26 g; 0.0117 mol) was stirred and heated for 4 hours at 60 ° C with acetic anhydride (17 ml). The reaction mixture was poured into water (150 ml) containing sodium hydroxide (18.4 g). The warm (50-60 ° C) reaction mixture was stirred vigorously for 1 hour and filtered. The product obtained was washed repeatedly with water, 30% methanol / water (10 ml) and finally with petroleum ether (b.p. 60-110 ° C). The resulting mixture (20: 1) contained a pyridin-5-one compound and a pyridin-7-one compound (5.66 g; m.p. 148-150 ° C). Example 3 - Preparation of a chromogenic substance

A mixture of 3'-carboxypyrid-2'-yl- (4-diethylamino-2-ethoxyphenyl) ketone (3.75 g; 0.01096 mol), 1-ethyl-2-methylindole (1.74 g; 0.01096 mol) and acetic anhydride (35 ml) was heated at 75 ° C for 5 hours. The reaction mixture was added dropwise to water (250 ml) containing sodium hydroxide (38.8 g). After stirring for several hours, the product was filtered. It was washed several times with water and finally with petroleum ether. The desired chromogenic material (3.37 g; 65%) was obtained which contained only small amounts of the pyridin-7-one compound by thin layer chromatography (silica).

ti 9 73174

The reaction proceeded in a similar manner using mixed keto acid isomers, but the resulting product contained more pyridin-7-one.

Example 4 - Preparation of chromogenic solutions

A number of chromogenic solutions were prepared by mixing the following components in the indicated amounts.

Table 1 1 2 3 4 5 il

Pyridyl blue --- 1.2 1.8 2.4 --- 1.2 1.2 CVL 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 N-102 1.1 1.1 0.6

Alkylate 2151 130.0 130.0 130.0 130.0 130.0 130.0 200.0

Ethyldiphenylmethane 70.0 70.0 70.0 70.0 70.0 70.0 --- 8 £ JO 11 12 13

Pyridyl blue --- --- 2.0 2.0 --- 2.0 CVL 3.4 3.4 2.0 2.0 3.4 2.0

Indolyl red 1,1 1,2 1,2 1,2 1,1 1,2 N-102 1,1 1,2 - --- 1,1 -

Other cryogenic material - --- - 1,0 (a) --- 1,0 (b)

Alkylate 215 126.4 130.0 200.0 200.0 130.0 180.0

Ethyldiphenylmethane 68.0 70.0 - - 70.0 ---

Other additives - - --- --- - 20.0 (c) * C 1-6 alkylbenzene (a) 3,7-Bis (diethylamino) -1O-benzoylbenzoxazine

(b) BLMB

(c) methyl myristate

Example 5 - Preparation of Microencapsulated Chromogenic Solutions Each of the chromogenic solutions 1-13 was microencapsulated according to the method described in U.S. Patent No. 4,111,040.

Briefly, 10 731 74 180 parts of the chromogenic solution were emulsified in a mixture of 35 parts of 10% EMA 31 (ethylene-maleic anhydride copolymer having a molecular weight of 75,000 to 90,000, supplied by Monsanto Chemical Co.,) in water, 32 parts A 20% EMÄ 1103 ethylene-maleic anhydride copolymer having a molecular weight of 5,000 to 7,000, supplied by Monsanto Chemical Co.) in water, 133 parts water, 10 parts urea and 1 part resorcinol, was adjusted to pH 3.5. After emulsification, 29 parts of 37% formaldehyde were 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.

Example 6 - Preparation of microcapsule coating compositions

Coating compositions were prepared from each batch of microcapsules 1-13 using the following substances and ingredients: parts wet parts dry

Capsule lot 80 40 wheat starch granules 10 10 * Penford 230, 10% 40 4 water 100 - 1

Etherified corn starch binder manufactured by Penick and Ford Ltd. Example 7 - Preparation of CB recording material

Each of the coating compositions 1-13 was dispersed, applied to a paper carrier and flattened no. With 12 wire-threaded coating rods, and the coatings were dried with a heat radiator. Example 8 - Comparative experiments on CB impairment

Each of the CB recording materials 1-13 was tested in a typewriter-intensity (TI) test in which a standard pattern is typed on a set of CF and CB sheets (the CF sheet is coated with zinc-modified phenol resin in this experiment as described in U.S. Pat. 3732120 and 3737410). A colored mark corresponding to the pattern is then formed on the CF sheet and the intensity of the mark is determined by means of an opacimeter.

Intensity is a measure of the amount of color development and is the ratio of the reflectance of the print to the reflectance (I / IQ) of the unimagined area, expressed as a percentage. A high value indicates low color development and a low value indicates good color development.

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Typewriter intensity experiments (T1) were performed before the CB sheet was exposed to fluorescent light radiation and one and two hours after the CB sheet was exposed to such radiation. In all cases, intensity determinations were performed 20 minutes after image formation.

The device used in the fluorescence light experiments consisted of a light box with a series of 18 fluorescent fluorescent lamps (21 inches (53.3 cm) long, rated power 13W) mounted vertically on 1-inch (approximately 2.5 cm) central supports. placed 1-1.5 inches (2.5-3.8 cm) from the lamps.

13 The results obtained for CB recording material were: CB recording- Original Change in T1 CB Coating Material no. _Tl_ after exposure_ 1 hour 2 hours exposure exposure_ 1 44 -20 -33 2 48 -12 -24 3 41 -12 -20 4 47 -12 -19 5 35 -15 -31 6 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

The amount of acceptable CB attenuation naturally depends on the duration of CB exposure. A reduction of 26 units in a two-hour exposure time is not acceptable. Thus, recording materials 2, 3, 4, 6, 7, 10, 11, and 13 containing pyridyl blue yielded a sufficiently small CB attenuation that was acceptable. Control recording materials 1, 5, 8, 9, and 12, to which no pyridyl blue had been added, showed excessive CB attenuation and were therefore not acceptable.

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Example 9 - Preparation of chromogenic solutions

Some more chromogenic solutions were prepared by mixing the following components in the indicated amounts.

14 V5 i_6

Pyridyl blue 91.8 91.8 --- CVL 21.6 21.6 91.8

Indolyl red 27.0 27.0 14.8 N-102 16.2 16.2 29.7 2,3,4-trimethyl-1,3-pentanediol diisobutyrate 3495.6 --- 3509.1

Magnaflux Oil 1747.8 3146.0 1754.6

Dibutyl phthalate --- 2097,4 ---

Example 10 - Preparation of Microencapsulated Chromogenic Solutions Each of the chromogenic solutions 14-16 was encapsulated according to the method described in U.S. Patent 4,100,103. The procedure was as follows: 5400 parts of chromogenic solution were emulsified in a mixture of 1000 parts of 10% EMÄ 31 in water and 5600 parts of water, the pH was adjusted to 3.7. The pH of the emulsion was then adjusted to 4.0. To the emulsion was added a mixture of 1000 parts of 10% EMÄ 1103 in water adjusted to pH 4.0, 1000 parts of water and 1000 parts of Resimene 714. The resulting mixture was heated at 55 ° C for two hours. The temperature of the mixture was then allowed to equilibrate to ambient temperature while maintaining stirring.

Example 11 - Preparation of microcapsule coating compositions

Coating compositions were prepared from each batch of microcapsules 14-16 using the following substances and amounts: parts dry

Capsule lot 70.40 wheat starch granules 21.10 etherified corn starch binder 4.25 poly (vinyl alcohol) binder 4.25

Sufficient solids were added to prepare a 17.4% composition for coating.

13,731 74

Example 12 - Preparation of CB recording materials

Each of the coating compositions 14-16 was dispersed and applied to a paper carrier using an air knife coating tester and dried.

Example 13 - Comparative Experiments on CB Attenuation CB recording materials 14-16 were subjected to the same experiments in the same manner as described in Example 8.

The results obtained were as follows: CB recording- Original Change in TI CB Coating Material No._TI_After Exposure_ 1 Hour 2 Hour Exposure Exposure 14 46 - 2 - 9 15 47 - 1 - 3 16 53 -17 -30 Using the same judging principle for acceptability as in Examples 8, it is seen that recording materials 14 and 15 containing pyridyl blue have excellent resistance to CB attenuation while a control that did not contain pyridyl blue, recording material 16, gave unsatisfactory results.

Example 14 - Preparation of a CF recording material containing pyridyl blue for a reverse transfer system_ (a) Pyridyl blue (1 g) was dissolved in acetone (150 ml). To this solution was then mixed precipitated calcium carbonate (70 g), Cabolite 100 urea-formaldehyde resin pigment (20 g; U.S. Patent 3,988,522) and zinc oxide (10 g; Green Seal 8, supplied by New Jersey Zinc Co., USA) and the resulting dispersion. allowed to dry under the hood.

(b) The product of step (a) was then formed into a coating composition using the following ingredients and amounts: 14,731 74 parts by weight dry weight% wet dry product of step (a) 84 84 83.4

Penford Gum 260 100 10 9.9 (modified maize starch)

Dow Latex 620 12 6 6.0 (carboxylated styrene-butadiene latex)

Tamol 731 3 0.75 0.7 (25% solution of the sodium salt of the polymeric carboxylic acid, ed. Rohm & Haas) water 250 _ 449 100.75 100 (c) The resulting composition was then applied at 34 lb (15.42 kg). ) for sheets of a stack of paper using no. 12 Mayer rods and dried.

The dry coating bar was about 4.5 lb (2.04 kg) per 500 sheets of rice with a sheet size of 25 x 38 inches (63.5 x 96.5 cm).

Example 15 - Preparation of CVL CF recording material for a reverse transfer system____

Steps (a), (b) and (c) of Example 14 were repeated replacing pyridyl blue with crystal violet lactone.

Example 16 - Alternative preparation method for CF recording material containing pyridyl blue_ (a) Pyridyl blue (300 g), calcium carbonate (600 g), 10% solids Penford Gum 230 (modified corn starch; 300 g), 25% solids Tamol 731 (30 g) and water (1200 g) were ground in a mill for 45 minutes with a few drops of octanol to prevent foaming.

(b) The product of step (a) was then formed into a coating composition comprising the following ingredients in said amounts: li 731 74 15 parts by weight dry weight% wet dry

The product of step (a) 6.3 2.0 3.0 calcium carbonate 43.4 43.4 65.8

Ansilex clay (U.S. Patent 3,568,523) 9.9 9.9 15.0

Penford Gum 230 66.0 6.6 10.0

Dow Latex 620 8.04.0 6.0

Calgon T 0.10.1 0.1 (molten sodium zinc phosphate glass powder composition) water 110.3 _ ____ 244.0 66.0 99.9 coating solids 27% viscosity 58 cps (c) The resulting composition was applied then on sheets of a 34 lb (15.42 kg) paper stack using an air knife coating, and when waded. The dry coating weight was about 4.5 lb (2.04 kg) per 500 sheets of rice measuring 25 x 38 inches (63.5 x 96.5 cm).

Example 17 - Alternative method of manufacturing CVL CF recording material_

Steps (a) (b) and (c) of Example 16 were repeated but replacing pyridyl blue with crystal violet lactone and replacing 300 g of calcium carbonate in step (a) with 300 g of zinc resinate.

The solids content and viscosity of the coating composition were 27%, 57 cps, respectively.

Example 18 - Preparation of acidic resin-containing CB and CFB sheets (a) p-Phenylphenol resin (1200 g; ppp resin) was dissolved in dibenzyl ether (3200 g) and Magnaflux oil (1600 g) with heating and stirring. EMA 31 (ethylene-roalein-anhydride copolymer having a grain density of 75,000-90,000, 200 g) was dissolved in deionized water (1800 g) with heating and stirring. The resulting EMA solution was diluted with deionized water (6000 g) and the pH was adjusted to 4.0 with 20% sodium hydroxide.

16,731 74 solution. The oil solution of the PPP resin was then emulsified into an EMA solution in a Cowles-type dissolution apparatus at 25 ° C. The emulsification was continued until the oil droplet averaged about 2 microns in size, with the droplet size ranging from about 0.5 to 15 microns. The resulting emulsion was then transferred to a water bath maintained at 55 ° C while 80% Resloom 714 (etherified methylol-melamine; 1000 g) diluted with deionized water (1000 g) was added with vigorous stirring. The resulting mixture was kept at 55 ° C for two hours while stirring continuously to effect capsule formation. After two hours, the temperature was allowed to slowly equilibrate to ambient temperature. Stirring was continued for another 16 hours.

(b) The microencapsulated solvent solution of PPP was then prepared as a coating composition having the following ingredients in the indicated amounts parts by weight_dry weight% dry wet

Capsules of step (a) 26.60 12.50 71.4

Stilt starch 3.20 3.12 17.9

Stayco S-starch 6.30 0.63 3.6

Dow Latex 638 2.50 1.25 7.1 (carboxylated styrene-butadiene latex) water 26.40 _ _ 65.00 17.50 100.00 coating solids 27% viscosity 68 cps (c) The resulting composition was then applied 34 lb (15.342 kg) paper stack sheets using air knife coating and dried. The dry weight of the coating was approximately 3.751 lb (1.7 kg) per 500 sheets of rice, giving a sheet size of 25 x 38 inches (63.5 x 96.5 cm). In addition, the composition was applied to the back surface of the recording materials prepared according to Examples 16 and 17 to produce CFB sheets.

731 74 17

Example 19 - Alternative Preparation of Acid Resin-Containing CB Sheet__ (a) An oil solution of p-octylphenol resin (1400 g; POP) in dibenzyl ether (3200 g) and Magnatlux oil (1600 g) was prepared using sufficient heat and stirring to effect dissolution. The oil solution was then microencapsulated using the method of Example 18, step (a).

(b) and (c) Steps (b) and (c) of Example 18 were repeated but using 27.30 parts by weight (wet) (instead of 26.60 parts by weight) of the POP capsules of step (a) and using the composition only with CB. to make sheets.

Example 20 - Comparison of recording materials containing frididyl blue and CVL

Pyridyl blue and CVL recorders were tested in a typewriter intensity experiment in which a standard pattern is typed on a duplicating kit with a CF and CB sheet and alternatively a CFB intermediate sheet. A colored print corresponding to the pattern is then created on the CF sheet or the CF side of the CFB sheet, and the intensity of the print is determined by means of an opacimeter.

Intensity is a measure of the amount of color development and is the ratio of the reflectance of the print to the reflectance (I / Io) of the unimagined area, expressed as a percentage. A high value indicates low color development and a low value indicates strong color development.

To compare the pyridyl blue and CVL recording materials, the following intensities were determined: A - Initial intensity, i.e., the intensity of the print image 24 hours after its development.

B - Image intensity after exposure to: (i) fluorescent light, (ii) natural sunlight, (iii) ambient conditions, or (iv) oven.

C - The intensity of the image transferred to a sheet previously exposed to: (i) fluorescent light, (ii) natural sunlight, (iii) ambient conditions, or (iv) an oven.

The device used in the fluorescent light experiments consisted of a row of 18 vertical fluorescent lamps (21 in. (53/3 cm) long, rated at 13 watts) mounted vertically at 2.50 cm (1 in) high supported by a medium support. Non-pictorial or pictorial sheets were placed 1-1.5 inches (2.5-3.8 cm) from the lamps for 24 hours. The patterning was performed on an IBM Executive typewriter using a font forming a four-line grid pattern.

Exposure of pictorial or non-pictorial sheets to daylight was performed by placing them in a south-facing window for 48 hours. The patterning was performed on an IBM Memory typewriter using the "X" font.

Exposure of pictorial or non-pictorial sheets to ambient conditions was accomplished by hanging them on a laboratory wall for 7 and 9 weeks, during which time the sheets were exposed to air, natural and fluorescent light, air temperature, and humidity. The patterning was performed on an IBM Selectric typewriter using a dot-forming font.

The sheets were kept in an oven at 140 ° F (60 ° C) for three weeks. The patterning was performed on an IBM Executive typewriter using a font forming a four-line grid pattern.

The results obtained are shown below:

Acid Resin Sheet Recording Material 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 16-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 40 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 96 731 74 1 9

Acid resin sheet As recordings of material A B (iii) C (iii) for 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) C (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

Example 17-CFB Example 17-CFB 35 55 76 A B (iv) C (iv)

Example 18-CB Example 16-CF 40 49 52

Example 18-CB Example 17-CF 48 49 75

Example 18 and Example 18 and

Example 16-CFB Example 16-CFB 48 45 51

Example 18 and Example 18 and

Example 17-CFB Example 17-CFB 51 51 68

It can be seen from the above examples, and in particular Examples 8, 13 and 20, that the chromogenic agent of the present invention is significantly superior to the crystal violet lactone. In particular, the image formed of the substance has better fading resistance and the substance itself is much less sensitive to light and thus remains reactive longer. In addition, in an inverse transfer system, a recording medium containing pyridyl blue is able to form a better intensity image than a recording medium containing crystal violet lactone.

Claims (8)

20 73174 Chromogenic substance, characterized in that it consists essentially of a compound of the formula C 7 <O> -> - «« V, which is 7- (1-ethyl-2-methylindol-3-yl) -7- (4 -diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro- [3,4-b] pyridin-5-one, optionally in admixture with an isomeric compound of formula tA% VN which is 5- (1-ethyl-2-methyl -indol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one. Chromogenic substance according to Claim 1, characterized in that it contains at least 90% of the pyridin-5-one isomer. Chromogenic substance according to Claim 2, characterized in that it contains at least 95% of the pyridin-5-one isomer. Pressure-sensitive recording material, characterized in that it contains a chromogenic substance according to one of Claims 1 to 3 as a component of its color-forming system. 5. The compound 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one and optionally 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one use as a chromogenic agent and as an agent for the loss of color formation reactivity of crystalline violet lactone and another chromogenic agent present. 6. The compound 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one and optionally use of 5- (1-ethyl-2-methylindol-3-yl) -5- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one as a chromogenic agent or as an anti-fading agent for the crystalline violet lactone and other chromogenic agent present. A method for improving the resistance of a recording material to a decrease in color-forming reactivity, characterized in that 7- (1-ethyl-2-methylindol-3-yl) - 7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one and optionally 5- (1-ethyl-2-methylindol-3-yl) -5 - (4-diethylamine-no-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one. A method for improving the resistance of a recording material to deterioration in fading resistance, characterized in that a compound 7- (1-ethyl-2-methylindol-3-yl) -7- (4-diethylamino-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-5-one and optionally 5- (1-ethyl-2-methylindol-3-yl) -5 - (4-diethylamine-no-2-ethoxyphenyl) -5,7-dihydrofuro [3,4-b] pyridin-7-one. 731 74 22