HU182923B - Copying sheet containing pyridil blue as colour forming material - Google Patents

Abstract

A pressure-sensitive record material comprising the colorless chromogenic dye Pyridyl Blue mixed with and adsorbed onto a pigment which is coated on a substrate sheet, and capsules containing an acidic resin dissolved in a suitable solvent, the capsules being coated on the same or an additional sheet. This "reverse" system (where the acidic resin rather than the dye is encapsulated) provides an improved community of properties, including improved image strength, print stability (fade resistance) and resistance to degradation. Pyridyl Blue is a mixture of the isomers 7-(1-ethyl-2-methylindol-3-yl)-7-(4-diethylamino-2-ethoxyphenyl)-5,7-d ihydrofuro[3,4-b]pyridin-5-one and 5-(1-ethyl-2-methylindol-3-yl)-5-(4-diethylamino-2-ethoxyphenyl)-5,7-d ihydrofuro[3,4-b]pyridin-7-one.

Description

The present invention relates to a transcription sheet comprising a coloring agent and optionally a suitable color developer, wherein the coloring agent is adsorbed on a water-insoluble chemically inert pigment. The transcription sheet of the present invention is characterized in that pyridyl blue is used as a coloring agent (chromogenic material) in an amount of 0.5-50% by weight of the pigment.

There is also provided a process for making this type of transcript and a pressure sensitive multi-sheet sequence comprising such a transcript. The base sheet of the transcription sheet is primarily paper but may also be a non-paper material such as plastic.

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

For such transcription sheets, the reactive coloring components and the solvent may be applied in a variety of configurations. One arrangement [see, for example, Chemical Abstracts. 77. 95 387 h and ibid, 89. 207 315q], referred to in the literature as a transfer arrangement, cover one side of a sheet with one of the sync-forming components, the color developer (referred to as "CF-sheet" in Anglo-Saxon literature and hereafter referred to as a "CF-type sheet") while a microencapsulated solution of the chromogenic material is coated on one side of another sheet (referred to as a "CB-type sheet"). The two sheets are then assembled into a series of sheets, bringing their coated sides into contact with each other. Thus, when pressure is applied to the uncoated side of the CB-type sheet, the solution is released from the other side to the coated side of the CF-type sheet, thereby undergoing a color reaction. A series of sheets may comprise one or more intermediate sheets (referred to in English as "CFB-sheet", hereinafter referred to as "CFB-sheet"), one side of which is a microcapsulated solution of one of the coloring components and the other side. side is coated with the other color forming component. In this way, additional copies are obtained if the individual sheets are properly arranged so that the solution containing the colorant is transferred from the pressure-sensitive CB-type to the pressure-sensitive CF or CFB-type.

In another arrangement, which may be called a two-component arrangement, a microcapsulated solution of one of the coloring components and the other of the coloring components are mixed together, or the resulting mixture is encapsulated in one sheet or coated with one of the coloring component microcapsules. with the other color forming component. When pressure is applied to such a transcription sheet, the solution is released from the microcapsules and reacts with the other coloring component to produce a colored reflection on the sheet that exactly corresponds to the shape of the pressure relay applied.

In both the transfer and the two-component system, the microcapsulated coloring component in solution is usually a chromogenic material, since this material is generally more sensitive to atmospheric destruction than the color developer. However, British Patent No. 1,337,924 has recently described a transcript which has a water-insoluble, chemically inert pigment coating and adsorbed on this pigment to a substantially colorless chromogenic material capable of reacting with a color developer. Adsorption on the pigment substantially stabilizes the chromogenic material against the destructive effects of the atmosphere and thus allows the use of a transcription sheet in a reverse arrangement in which the solvent solution of the color developer is microencapsulated rather than the chromogenic material. This arrangement will be hereinafter referred to as the "reverse system".

Although several other chromogenic substances are mentioned, there is in fact only one chromogenic substance, namely crystalline violetactone - 1,1-bis [4-dimethylamino) phenyl] 5- (dimethylamino) -1,3-dihydro- benzo [c] furan-3-one, is disclosed in British Patent No. 1,337,924 for transcription sheets. The use of this chromogenic material results in a transcript that is excellent for use in a reverse system 35, but has many features that need to be improved or improved. Characteristics to be improved include the intensity of the colored mirror image (hereinafter simply referred to as "mirror image intensity"), the resistance of the mirror image to discoloration40, and the resistance of the adsorbed chromogenic material to the destruction of the atmosphere.

It is an object of the present invention to provide a reverse transcription sheet layout having more advantageous properties than those known in the art.

It has now been found that a transcription sheet with improved properties is obtained by providing a solution of the sheet with a water-insoluble and chemically inert pigment having adsorbed on chromogenic material 50, referred to as pyridyl blue. In fact, the use of pyridyl blue in the transcription sheet according to the invention provides increased resistance to atmospheric destruction and discoloration as well as improved mirror image intensity, while retaining all the benefits of reverse transcription.

Pyridyl blue itself is a novel chromogenic material whose structure is illustrated by any or all of the two formulas shown in the attached drawing, i.e., it can be understood as a mixture of stereoisomers 60. The two formulas are generically designated 5- (1-ethyl-2-methylindol-3-yl) -5- [4- (diethylamino) -2-ethoxyphenyl] -5,7-dihydrofuro [3, 4-b] pyridin-7-one [formula I in the drawing] and 7- (1-ethyl-2-methylindol-3-yl) -7- [4- (diethylamino-2-ethoxy) phenyl] -5,7-di65 hydrofuro [3,4-b] pyridin-5-one [formula II in the drawing].

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Chem. Abs., 83, 35,759 (Japanese Patent Publication No. 75-5116) discloses indole-substituted pyridine carboxylic acid lactones but does not describe pyridyl blue itself.

Any of the two stereoisomers can be used as chromogenic material for the transcription sheets of the invention, although the use of the pyridin-5-one isomer is more effective. However, the use of processes for the preparation of pyridyl blue (see, for example, British Patent No. 1,367,567 or U.S. Patent No. 3,775,444) usually results in a mixture of isomers. However, separation of the individual isomers from this mixture by conventional techniques such as chromatography is difficult, time consuming and very costly on an industrial scale. Therefore, it is preferable to use either a mixture of isomers or a synthetic method for the preparation of pyridyl blue wherein the reaction conditions are chosen to favor the formation of the pyridin-5-one isomer. Thus, a mixture of isomers in which the more potent pyridin-5-one isomer is dominant can be used in the present invention. When reacted with a suitable color developer, the pyridyl blue yields a blue level.

The water-insoluble and chemically inert pigments for use in the transcription sheet of the present invention include, for example, calcium carbonate, zinc oxide, barium sulfate, titanium dioxide, barium carbonate, magnesium carbonate, calcium oxide, magnesium titanate, and the like. zinc sulfide. However, calcium carbonate is preferred.

In the transfer arrangement, the transcription sheet of the invention may be used alone as a CF-type sheet or may be coated on the other side with a solution of a color developer in a sealed microcapsule to form a CFB-type sheet. In the case of a two-component system, a solution of a color developer encapsulated in a microcapsule, preferably pre-formed, is distributed in the transcription sheet, or else the transcription sheet is coated with such a solution.

The transcription sheet of the present invention is based primarily on paper but may be provided with a plastic coating, preferably on a paper base.

The process for making the transcription sheet according to the invention will now be described. According to the present invention, the pyridyl blue is adsorbed on a water-insoluble, chemically inert pigment and then coated with a composition containing the pigment so treated to form the base of the transcription sheet.

The nature of the method for adsorbing pyridyl blue on the pigment is not critical to the practice of the invention, the only requirement being to ensure that the pyridyl blue is adsorbed on the pigment in its colorless state. Methods that can be used for this purpose include, for example, the method of passing a solution of pyridyl blue through a pigment bed, similar to chromatographic methods, or a method of precipitating pyridyl blue from solution in the presence of pigment by one of several methods known in the chemical technology for precipitation. Examples of precipitation methods include:

Diluting the pyridyl blue solution with a solvent miscible with the solution but unable to dissolve the pyridyl blue;

chemically neutralizing an aqueous acidic solution of the pyridyl blue;

cooling the hot pyridyl blue solution;

evaporating the solvent from the pyridyl blue solution.

By performing any of these methods, a water-insoluble, chemically inert pigment is obtained on which pyridyl blue is adsorbed.

Compositions containing pyridyl blue adsorbed on the pigment can be layered onto the sheet of the transcription sheet by any of the methods commonly used to make pressure-sensitive transcription sheets. For example, the so-called Mayer roller or airknife coating method can be used.

Said composition itself is usually aqueous and contains a suitable binder such as latex and / or starch based on styrene butadiene. Additionally, the composition may contain minor amounts of conventional additives for paper coating, such as wetting agents and antifoams.

Further information on the coating methods and formulations which may be used in carrying out the process of the present invention is provided in U.S. Patent Nos. 3,627,581, 3,775,424 and 3,853,869. However, when applying the technical solutions described in these patents to the process of the present invention, care should be taken that, if transcription sheets are to be used in the transfer arrangement, the composition comprising the pigment adsorbed pyridyl blue on the CF sheet or CF side of the CFB sheet must be layered. However, the microencapsulated solution of the color developer should be applied to the CB type sheet or the CB side of the CFB type sheet. As mentioned above, this is an inverse arrangement to the state of the art in the manufacture of pressure sensitive transcription sheets.

If the transcription sheet is to be used in the aforementioned two-component system, i.e., it is desired to apply both coloring components to the same sheet as the basis of the transcription sheet, then the coating composition must also contain a microencapsulated solution of the color developer.

As a color developer, any material previously used for pressure-sensitive transfer papers can be used. Of course, it is a basic requirement for a color developer for use in the present invention that it be soluble in a solvent and give a color with pyridyl blue. Examples of suitable colorants include acid novolac resins such as 4-phenylphenol and formaldehyde or 4-octylphenol and formaldehyde.

The solvent used for these acid resin-type color developers may also be one of the solvents commonly used for pressure-sensitive transfer papers. Preferred examples include dibenzyl ether, magnaflux oil (a saturated hydrocarbon oil that distils between 188 ° C and 260 ° C), benzyl benzoate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (described in the literature as "TX1B"). "And disclosed in U.S. Patent 4,027,065), dibutyl phthalate, 1,2,4-trimethylbenzene, ethyldiphenylmethane (U.S. Patent 3,996,405). disclosed). However, a mixture of dibenzyl ether and magnaflux oil is most preferred.

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A solution of an acidic resin-type color developer in one of the solvents mentioned may be microencapsulated or the required microcapsules may be prepared from gelatin (see U.S. Patent No. 3,041,289), a urea-formaldehyde polymer (see U.S. Pat. No. 4,001,140). from U.S. Patent No. 3,755,190), polyvinyl alcohol-walled capsules containing resorcinol-formaldehyde resin as filler (see U.S. Patent No. 3,755,190) or various melamine-formaldehyde resins (see U.S. Pat. No. 4,100,103). See U.S. Patent No. 5,198,198.

Finally, the present invention relates to a series of pressure sensitive disposed sheets comprising a transcription sheet as described hereinbefore.

The invention will now be further illustrated by the following embodiments.

Example 1

Preparation of pyridyl blue

A mixture of 0.21 mol of quinoline anhydride (2,3-pyridinedicarboxylic anhydride) and 0.33 mol of 1-ethyl-2-methylindole was stirred in a reaction vessel at 65-70 ° C for 3 hours and then cooled with benzene (or washed with chlorobenzene) to give (1-ethyl-2-methylindol-3-yl) - (3-carboxy-2-pyridyl) ketone and its isomer.

A total of 58 g (0.188 mol), 35.3 g (0.188 mol) of Ν, Ν-diethyl-m-phenethidine and 250 ml of acetic anhydride from the latter isomer mixture was stirred at 60-65 ° C for 2 hours and then poured into 500 ml of water. and one hundred acetic anhydride were hydrolyzed by slow addition of 450 ml of 29% ammonium hydroxide solution. After stirring for 2 hours, the precipitate was filtered off and washed successively with water, 200 ml of 40% methanol in water and 50 ml of boiling point petroleum ether 60-110 ° C. The precipitate is then dried to constant weight in a 75 ° C oven. A total of 80.5 g (90%) of 7- (1-ethyl-2-methylindol-3-yl) -7- [4- (diethylamino) -2-ethoxyphenyl] -5,7-dihydro -furo [3,4-b] pyridin-5-one and 5- (1-ethyl-2-methylindol-3-yl) -5- [4- (diethylamino) -2-ethoxyphenyl] - A mixture of 5,7-dihydrofuro [3,4-b] pyridin-7-one with a 9: 1 weight ratio, m.p. 134-137 ° C is obtained.

Example 2

Preparation of CF type transcription sheet containing pyridyl blue

(a) Dissolve 1 g of pyridyl blue in 150 ml of acetone and add 70 g of precipitated calcium carbonate, 20 g of urea-formaldehyde resin (prepared in U.S. Patent 3,988,522) as a pigment and 10 g of zinc. oxide (marketed by New Jersey Zinc Co., USA under the trade name Green Seal 8). The resulting dispersion is then allowed to dry in a booth.

b) The product of step a) is processed into a coating composition with components in the proportions described below.

c) The composition obtained in step b) is applied to a paper stack of 15.42 kg using a Mayer roller No. 12 and dried. The dry weight coating weight is about 2.04 kg of 500 pieces of rice with 63.5 * 96.5 cm sheets.

Part Weight Weight% Wet Dry (dry standing) step a) 84 84 83.4 Penford Gum 260 modified corn starch 100 10 9.9 Dow Latex latex 620 branded with carboxylated styrene and butadiene 12 6 6.0 Tamol 731 (25% solution of a sodium salt of a polymeric carboxylic acid, supplied by Rohm and Haas) 3 0.75 0.7 WATER 250 449 100.75 100.0

Example 3: (counterexample)

Preparation of CF-type transcript sheet containing crystal violet lactone

The procedure of Example 2, steps a), b) and c) was followed except that the pyridyl blue was replaced by crystal violet lactone.

Example 4

Alternative method for the production of CF type transcription sheet containing pyridyl blue

a) In the Attritor (abrasive mixer), 300 g of pyridyl blue, 600 g of calcium carbonate, 30 g of Tamol 731 (10% solids) are ground for 45 minutes, with a few drops of octanol added to reduce foaming. .

b) The product obtained in step a) is processed into a coating composition with components taken in the following ratios:

Weight% Weight%

Wet Dry (dry standing) The product of step a) 6.3 2.0 3.0 calcium carbonate 43.4 43.4 65.8 Ansilex Clay (U.S. Pat. No. 3,586,523) description 9.9 9.9 15.0 Penford Gum 230 66.0 6.6 10.0 Dow Latex 620 8.0 4.0 6.0 Calgon T (bulk sodium zinc phosphate - glass- powder composition) 0.1 0.1 0.1 water 110.3 244.0 66.0 99.9 The solids content of the coating composition is: 27% Viscosity of the coating composition: 58 cPs

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c) The composition of step b) is applied with a so-called "air-knife" coating on a paper bag weighing 15.42 kg and dried. The dry weight coating weight is about 2.04 kg of 500 pieces of rice consisting of 63.5 x 96.5 cm sheets.

Example 5

Preparation of CF-type transcript sheet containing crystal violet lactone

The procedure described in steps a), b) and c) of Example 4 is repeated, except that crystalline viololactone instead of pyridyl blue and

In step a) 300 g of zinc resinate are used instead of 300 g of calcium carbonate. The coating formulation used in step c) has a solids content of 27% by weight and a viscosity of 57 cPs.

Example 6

Production of CB and CFB sheets containing acid resin as color developer

a) 1200 g of 4-phenylphenol-based resin (hereinafter referred to simply as PPP resin) are dissolved in a mixture of 3200 g of dibenzyl ether and 1600 g of Magnaflux oil under heating and stirring. At the same time, 200 g of the polymer "ΕΜΑ 31" (a molecular weight copolymer of ethylene and maleic anhydride of 75,000 to 90,000) are dissolved in 1800g of deionized water with heating and stirring. The resulting EMA solution was diluted with 6000 g deionized water and adjusted to pH 4.0 with 20% sodium hydroxide solution. The oily solution of the PPP resin was then emulsified in a Cowles-type solids dissolution apparatus at 25 ° C in the EMA solution until the oil droplets had an average particle size of about 2 microns and a droplet size distribution of about 0.5 to about 15 microns. at its extreme values. The resulting emulsion was then placed in a water bath maintained at 55 ° C and 80 g of Resloom 714 (etherified methylol melamine) diluted with 1000 g, diluted with 1000 g of deionized water with rapid stirring. The resulting reaction mixture was heated at 55 ° C for 2 hours to allow constant agitation and thus to form capsules. After 2 hours, the temperature was allowed to slowly return to ambient temperature and stirring was continued for an additional 16 hours.

b) The microcapsulated solution of the PPP resin prepared as described in step a) is processed into a coating composition with components in the following proportions:

Part Weight Weight% wet dry (dry standing) encapsulated in step a) solution 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 water 26.40 65.00 17.50 100.0

The resulting coating formulation has a solids content of 27% by weight and a viscosity of 68 cPs.

c) Using the coating composition obtained in step b) using a so-called "air-knife" type apparatus, a paper stack weighing 15.42 kg is coated and dried. The dry weight coating weight is about 1.7 kg for a 500 piece rice consisting of 63.5 x 96.5 cm sheets.

In addition to the coating step described in the previous paragraph, the backsheet of the transcription papers obtained by the process described in Examples 4 and 5 is coated with the coating formulation obtained in step b) to obtain CFB-type transcription papers.

Example 7

Alternative method for making a CB type sheet containing acid resin as a color developer

a) Prepare a solution of 1400 g of 4-octylphenol-based resin (hereinafter simply referred to as POP resin) in 3200 g of dibenzyl ether and 1600 g of Magnafluxol, using sufficient heating and stirring to effect dissolution. The resulting oily solution is then microencapsulated as described in Example 6 (a).

b) and c) The procedure of steps b) and c) of Example 6 is repeated, except that 27.30 parts by weight of the POP resin capsules prepared according to step a) of the example are used instead of 26.60 parts by weight. or the resulting coating formulation is used only to produce a CB type sheet.

Example 8

Comparison of black sheets containing pyridyl blue and crystal violet lactone

Gyratory papers containing pyridyl blue and crystal violet lactone are subjected to typewriter intensity tests by punching a standard shape or typing a series of sheets containing a CF and a CB type sheet and optionally an intermediate CFB type sheet. Thus, a color printed mirror image of the shape is formed on the CF-type sheet or CF-sheet of the CF-type sheet, and the intensity of the mirror image is determined using a transparency meter.

The measured intensity is the degree of color appearance or, in fact, the percentage (I / I _o ) of the reflectance of the printed mirror image to the non-printed area. A high value represents a poor color appearance while a low value represents a large color appearance.

The following intensities are determined for comparison of transfer papers containing pyridyl blue and crystal violet lactone:

A - original intensity, that is, the intensity of a printed mirror image 24 hours after onset

B - the intensity of a mirror image after exposure to:

(i) fluorescent light (ii) natural sunlight (iii) environmental storage or (iv) oven storage

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C - Intensity of a mirror image on a sheet previously subjected to the following effects:

(i) fluorescent light (ii) natural sunlight (iii) environmental storage or (iv) oven storage

The apparatus used for fluorescent light testing consists of an illumination box in which a series of 18 daytime fluorescent lamps (each 53.3 cm long and rated at 13 watts) are mounted vertically on nearly 25 mm central brackets. Plates with or without a mirror image are kept in the illuminator box at a distance of 2.5 cm to 3.8 cm from the lamps for 48 hours. The mirror image is created using an IBM US typewriter "Executive" using a "4-bar" cross-type letter.

Exposed or mirrored pages are exposed to natural sunlight by placing them in a window facing south for 48 hours. The mirror image is created using IBM's "Memory" typewriter, using the letter "X".

Exposed or non-reflective sheets are exposed to ambient storage by hanging them on a laboratory wall and leaving them exposed for 7 to 9 weeks during which time the sheets are exposed to 1 q of air, natural and fluorescent light, and air. temperature and humidity. The mirror image is created using IBM's "Selectric" typewriter, using a solid block type letter,

The plate, with or without a mirror image, is placed in an oven for 3 weeks at 60 ° C. The mirror image is created using IBM's "Executive" typewriter, using a "4-bar" cross-type font.

The results obtained are as follows:

Acid resinous sheet Átírólap THE B (i) C (i) CB of Example 6 CF of Example 4 38 48 55 CB of Example 6 CF of Example 5 51 74 78 CFBs of Examples 6 and 4 CFBs of Examples 6 and 4 49 51 56 CFBs of Examples 6 and 5 CFBs of Examples 6 and 5 52 68 75 THE B (ii) C (ii) CB of Example 6 CF of Example 2 40 41 65 CB of Example 7 CF of Example 2 52 53 75 CB of Example 6 CF of Example 3 40 52 88 CB of Example 7 CF of Example 3 56 74 96 7 weeks THE B (iii) C (iii) CB of Example 6 CF of Example 4 33 38 48 CB of Example 7 CF of Example 4 44 56 54 CB of Example 6 CF of Example 5 34 45 72 CB of Example 7 CF of Example 5 57 73 89 9 weeks THE B (iii) C (iii) CB of Example 6 CF of Example 4 32 42 44 CB of Example 6 CF of Example 5 34 54 76 CFBs of Examples 6 and 4 CFBs of Examples 6 and 4 33 42 45 CFBs of Examples 6 and 5 CFBs of Examples 6 and 5 35 55 76 THE B (iv) C (iv) CB of Example 6 . CF of Example 4 40 49 52 CB of Example 6 CF of Example 5 48 49 75 CFBs of Examples 6 and 4 CFBs of Examples 6 and 4 48 45 51 CFBs of Examples 6 and 5 CFBs of Examples 6 and 5 51 51 68

From the foregoing results, it is clear that the transcription sheet of the present invention has a significantly more favorable property than the known transcript containing the same amount of crystalline violetactone. Specifically, it has increased resistance to degradation (including atmospheric degradation) and provides a mirror image with increased intensity and discoloration.

Claims (1)

PATENT CLAIMS 1. A transcription sheet comprising a coloring chromogenic material and optionally a color developer adsorbed on a water-insoluble pigment chemically inert, characterized in that the coloring material is pyridyl blue, i.e. 7- (letyl-2-methylindol-3-yl) -7- [ 4- (diethylamino) -2-ethoxyphenyl · 5,7-dihydrofuro- [3,4-b] pyridin-5-one and / or 5- (1-ethyl-2-methylindole-3) yl) -5- [4- (diethylamino) -2-ethoxyphenyl] -5,7-dihydrofuro [3,4-b] pyridin-7-one - 0.5 to 50% by weight of pigment %. Two drawings