DE2245504A1 - FLUORANE DERIVATIVES - Google Patents

Description

Applicant: NISSO ΚΑΚΟ CO., LTD.

—————— 1-60, 3-Chome, Ukima, Kita-ku, Tokyo / Japan

Fluoran derivatives

The present invention relates to new fluoran derivatives and their use as a color-forming component in Recording materials.

The present invention accordingly relates to new fluoran derivatives of the general formula

C = O

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wherein R is a lower alkoxy group in the p- or o-position is related to the imino bond. The term "lower" preferably denotes groups with 1 to 6 carbon atoms. The present invention also relates to a recording method which is characterized in that that a fluoran derivative of the above formula I is brought into intimate contact with an electron-attracting substance with the above fluoran derivative developing a color.

Fluoran derivatives of the above formula I are substances which are themselves practically colorless. These substances have the property that when they come into contact with an electron accepting substance, e.g. acids, clays, Phenol-formaldehyde resins, bisphenol A etc. are brought to develop a deep color. If a solution to the mentioned fluoran derivatives in an inert solvent in contact with clay or a phenol-formaldehyde resin is brought, a deep color develops. Furthermore, a color is developed by fine powdered fluoran derivative and finely divided clay or phenol-formaldehyde resin in intimate contact under pressure come, or that a mixture thereof is brought into intimate contact while this mixture is at least heating to a temperature above the melting point of either component of the mixture. Because of the Properties described above are fluoran derivatives of Formula I above useful as color-forming materials for use in the manufacture of copier or recording papers, for example pressure-sensitive Copier materials, pressure-sensitive recording materials, heat-sensitive recording materials, heat-sensitive copying materials, etc. These fluoran derivatives can also be used as color-forming materials for Printing with colorless ink, because when a sheet of paper, the surface of which is covered with an elec-

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tronenacceptor is coated with an ink or Printing ink is printed, which contains a fluoran derivative according to the invention dissolved, on the paper surface color is developed in the printed areas.

Accordingly, a pressure-sensitive copying material can be produced by using a sheet of paper, its underside with an emulsion containing micro. capsules are coated in an inert organic Solvent containing a fluoran derivative of the general formula I dissolved, and a paper sheet, the surface of which with an electron acceptor such as clay or phenol-formaldehyde resin is coated, can be combined into one set. As a pressure-sensitive recording material A sheet of paper can also be used that has a mixture of said microcapsules and an electron acceptor such as clay or phenol-formaldehyde resin on the surface is coated.

When words or figures are printed or written on the surface of a sheet of paper, plural surface with fine particles of such an electron ring; taking substance, for example clay or phenol-formaldehyde resin, has been coated, and a solution! in an inert organic solvent or an ink-like material containing a fluoran derivative of the general formula I is used, this solution or this ink-like material essentially is colorless, the words or figures so printed or written will appear on the surface of the Sheet recorded. Using a typewriter ribbon that with such a solution in is impregnated with an inert organic solvent or such an ink-like liquid, can a sheet of paper coated on the surface with an electron-accepting substance with a writing

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machine to be described. On the surface of one Paper sheet, the surface of which is coated with a mixture of fine particles of a fluoran derivative of the general, Formula I, fine particles of an electron accepting substance such as clay, phenol-formaldehyde resin or bisphenol, and a binder such as polyvinyl alcohol, becomes a Color develops when this surface comes into contact with a heat pen or heat type, and thus can use such paper as a heat-sensitive recording material be used. Such paper can also be used for copying, as the color develops through intimate contact with the flurane derivative with the electron-accepting substance takes place when a thin sheet of an original that on his Surface with a to absorb infrared rays enabled material (e.g. Chinese ink, black ink, etc.) is provided with figures, in close contact brought to the surface of the paper and irradiated with strong infrared radiation. The paper can also be written on by applying strong local pressure to the surface of the sheet will.

Useful carriers for the fluoran derivatives of Formula I, these fluoran derivatives containing microcapsules and electron acceptors for recording materials of the types described above are high molecular weight substances in the form of films, fabrics or non-woven fabrics, including papers.

The fluoran derivatives of general formula I have three characteristic properties as color-forming compounds if they have a color due to their ability to be used for recording materials: the first property is that this

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"" J ™ *

.Derivatives develop colors very quickly when using Clay or an electron accepting resin. The second property is that that the dyes developed thereby have excellent lightfastness, and the third property is that these derivatives have excellent water resistance and do not sublime at all

Color shades obtained by contacting the fluoran derivatives of the general formula I with electron-accepting substances are given in Table 1. However, it is also possible to change the hue with the fluoran derivatives of the general formula I by mixing them with other chromogenic materials which develop a different hue, and it is thereby also possible to change the hue of other chromogenic change materials? ■ those of the present invention are mixed in-the with the fluoran derivatives according to. The lightfastness of the fluoranj derivatives according to the invention can be enhanced by adding, for example, ultraviolet absorbers, etc.

The manufacture of a pressure sensitive copy sheet using a fluoran derivative of the general formula I can, for example, according to the in the U.S. Patents 2,800,458 and 2,969,370 take place. When using the fluoran derivatives in heat-sensitive recording sheets or copying sheets For example, those in Japanese Patent Publication Nos. 6040/1965, 4160/68 and 14039/70 are used.

Shades and melting points for the fluoran derivatives of the formula I mentioned, for example, are given below Table 1 compiled.

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TABLE 1

C ₂ H 2 ^f _ η ^. CH _x Hue, c mdevelops resin Enamel with a Electrical black Point 10 C ₂ H 4 · kAc AJJ-NH - ^ - ^ S nenacceptor . ( ⁰ C) ^R activate Dark 183-186 4 · the tone green R = - OCH, Dark green 189-191 violet R = - OCH, Blackness 176.5 - D. lich-green 177.5 R = - OCoH ₁ . Blackness lich-pur- pure

The fluoran derivatives according to the invention, which correspond to the following general formula

(I)

where R is a lower alkoxy group can be prepared by o- (4-diethylamino-2-hydroxybenzoyl) benzoic acid the formula

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22Α550Λ

(H)

COOH

in approximately equiraolar amounts with a 4-hydroxy-2-methyldiphenylamine derivative the formula

(III)

where R has the same meaning as above, ¹

in concentrated sulfuric acid at 0 to 20 reaction.

C to

It is known to implement G- (4-diethylamino-2-hydroxybenzoyl) benzoic acid in the presence of dehydrating agents such as sulfuric acid with phenols to form fluoran derivatives. Up to now, however, this reaction has been carried out at temperatures of 130 to 150 ^° C. or under even higher temperature conditions, fusing with zinc chloride. The inventors have found that the desired fluoran Deriväte of the formula I can be surprisingly then obtained in good yield when the reaction between the compounds of formulas II and III at such niedrirgen temperatures such as -10 to +50 ⁰ C, preferably -5 to +5 ⁰ C, although the above-mentioned desired fluoran derivatives cannot be obtained when the above-mentioned reaction is carried out at the above-mentioned high temperatures. - 8th -

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The 4-hydroxy-2-methyldiphenylamine derivatives of the above Formula III used in this reaction are new compounds that can be obtained by using 4-amino-m-cresol hydrochloride and an aniline derivative in the absence of a catalyst or in the presence of zinc chloride, calcium chloride, magnesium chloride or the like can be refluxed. In this case, the addition of a small amount of metallic is Tin is effective in preventing discoloration of the product.

The invention is further illustrated by the following examples.

Production example 1

15 g of o - ^ - diethylamino-Z-hydroxybenzoyl) benzoic acid and 17.5 of 4-hydroxy-2-methyl-4'-ethoxydiphenylamine are slowly added with stirring to 110 g of concentrated sulfuric acid, and the mixture obtained is heated to 0 to 5 ^{0 for 48 hours} C stirred. After completion of the reaction, the reaction mixture is poured into 50 ml of ice water, and the precipitated crystals are collected by filtration. The crystals are dissolved in 500 ml of toluene. The solution obtained is washed several times with a three percent sodium hydroxide solution and then with an oil hydrochloric acid solution until the aqueous layer becomes clear. Then the solution is washed with water and treated with activated charcoal. After filtration, the solvent (toluene) is distilled off under reduced pressure. 500 ml of isopropyl alcohol are added to the distillation residue. The mixture is heated to reflux and then left to stand overnight. The precipitated crystals are filtered off with suction, whereby -15 · 1 g of 3-diethylamino-6-methyl-7-p-phenetidinofluoran ⁱ as pale pink-white crystals with the high point 176.5

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to 177.5 ⁰ G can be obtained. The 4-hydroxy-2-methyl-4 ^f -ethoxydiphenylamine used here was prepared as follows.

20 g of 4-amino-m-cresol hydrochloride, 55 g of p-phenetidine and 10 g of zinc chloride are placed in a four-necked flask. The reaction is carried out for three hours at 180 to 200 ^° C. with stirring. The reaction mixture is then adjusted to pH 7.0 with dilute sodium hydroxide solution and extracted with 300 ml of toluene. The extract is then filtered off with suction and the toluene is distilled off. After distillation under reduced pressure, 17.5 g of a distillate with a boiling point of 235 to 245 ° C / 13 imuHg are obtained.

Production example 2

15 g (4-diethylamino-2-hydroxybenzoyl) benzoic acid and 11 g of 4-hydroxy-2-methyl-2 ^f -methoxydiphenylamine are slowly added with stirring to 110 g of concentrated sulfuric acid, and the resulting mixture is 24 hours stirred at 0 to 5 ^{° C.} After the reaction has ended, the reaction mixture is worked up in the same manner as described in Preparation Example 1, 6 g of 3-diethylamino-6-methyl-7-o-anisidinofluoran in the form of pale pink-white crystals with a melting point of 183 to 186 ⁰ C.

The 4-hydroxy-2-methyl-2 ^l -methoxydiphenylamine used therein was prepared as follows: In a four-necked flask were placed 10 g of 4-amino-metacresol hydrochloride, 23 g of o-anisidine and 3 g of zinc chloride, and the reaction was carried out for three hours long carried out at 180 ⁰ C bis.200. The reaction mixture was adjusted to pH 7.0 with dilute sodium hydroxide solution and then extracted with -300 ml of toluene. The extract was then filtered off with suction and the toluene was distilled off. To

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Distillation under reduced pressure gave 11 g of a distillate with a boiling point of 190 to 204 ° C./5 mmHg;

example 1

1.0 g of 3-diethylamino-6-methyl-7-o-anisidinofluoran is dissolved at 80 ⁰ C in 20 g alkylnaphthalene (liquid A). In addition, 2.0 g of gelatine (isoelectric point: 8.0) and 0.5 g of CMC are completely dissolved in 120 ml of water (liquid B). Subsequently, the liquid A is mixed with the liquid B at £ Ö to 60 ⁰ C, and the resulting mixture is emulsified with stirring at high speed. The enulsified liquid is adjusted to pH 8.5 to 9.0. The resulting emulsion is then stirred at high speed for 20 minutes and the pH is gradually adjusted to 4.4 by adding dilute hydrochloric acid or acetic acid. The liquid is cooled to 5 to 10 ^° C. with continuous stirring, 6 g of formalin (37 %) are added, and stirring is continued at 10 to 20 ^° C. for a further hour. The solution obtained is adjusted to pH with sodium hydroxide solution (5 %). The emulsion obtained is slowly stirred for a few more hours, microcapsules being formed in the emulsion which contain an alkylnaphthalene solution of 3-diethylamino-6-methyl-7-o-anisidinofluoran.Each of these microcapsules is made of a sufficiently solidified film of CMC and gelatin formed. A sheet of paper is coated on one side with the emulsion obtained and allowed to dry. Independently of this, a sheet of paper is coated on the surface with activated clay and allowed to dry. The first-mentioned sheet is placed on the second sheet so that the coated side of the first sheet comes into contact with the clay-coated side of the second sheet. \] emi places on the surface; of the first

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Are written on the second sheet of paper, these words quickly become black on the clay layer of the second Developed leaf. .

Example 2 '

1 g of 3-diethylamino-6-methyl-7-p-anisidinofluoran is dissolved in 20 g of dibutyl phthalate (liquid A). In addition, 2.0 g of gelatine (isoelectric point: 8.0) and 0.5 g of CM.C. completely dissolved in 120 ml of water (liquid B). Then liquid A is mixed with liquid B at 50 to 60 ° C. and the resulting mixture is emulsified by stirring at high speed. The emulsified liquid is adjusted to pH 8.5 to 9.0. The resulting emulsified liquid is then stirred at high speed for 20 minutes and the pH of the liquid is gradually adjusted to 3.8 by adding dilute hydrochloric acid or acetic acid. The liquid is cooled to 5 to 10 ^° C. with continuous stirring, 6 g of formalin (37 %) are added, and stirring is continued at 10 to 20 ^° C. for a further hour. The solution obtained is adjusted to pH 9.0 with sodium hydroxide solution (5 %)

stirred, whereby microcapsules are formed in the emulsion, 'which in' a dibutyl phthalate solution 3-diethylamino-6- | contain methyl-7-o-anisidiriofluoran. Each of these microcapsules consists of a sufficiently solidified film; made of CMC and gelatin. A sheet of paper is coated with the resulting emulsion on one surface and allowed to dry. In addition, a sheet of paper is coated on the back with activated clay and allowed to dry. The former sheet is placed on the second sheet so that the coated ^: side, of the first sheet comes into contact with the clay-coated side of the second sheet. When words are written on the surface of the first sheet,

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these will quickly develop into a black-green color on the clay.

Example 3

1.0g 3-diethylamino-6 ~ methyl-7 ~ p ~ phenetidinofluoran and 0.15g 3-diethylamino-6-methyl-7 - dibenzylaminofluoran are heated together with 20 g of alkyl diphenyl to 100 ⁰ C, to prepare a solution (liquid A) . In addition, a liquid B is prepared in the same way as described in Example 1. By mixing the liquid A with the liquid B according to the method described in Example 1, an emulsion is produced. A sheet of paper is coated with the emulsion on one surface and allowed to dry. Independently of this, a sheet of paper is placed on a surface

coated with a phenol-formaldehyde resin and dry calmly. The first sheet is placed on top of the second sheet so that the coated side of the first sheet comes into contact with the resin coated side of the second sheet. When words hit the surface of the ϊ are written on the first sheet, they will quickly ι in black color on the resin-coated side ■ of the second leaf developed. !

Example 4 j

35 g of 3 ~ diethylamino-6-methyl-7-p-phenetidinofluoran, 150 g of an aqueous polyvinyl alcohol solution above (the polyvinyl alcohol used is a 98% hydrolyzate) and 65 g of water are mixed for one hour rubbed to make a dispersion. The particle diameter of 3-diethylamino-6-methyl-6-p-phenetidinofluoran after rubbing is 1 to 3 microns (component A). In addition, 35 g of ^^ - isopropylidenediphenyl (Bisphenol A), 150 g of a 10> 6 polyvinyl alcohol and 65 g of water for one hour in a whipping

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mill mixed together. After rubbing in, amounts to the particle diameter of bisphenol A is 1 to 3 microns (Component B).

Then a sheet of paper is placed on a surface with a mixture of 3 g component A and 67 g component B coated and allowed to dry to obtain a heat-sensitive recording sheet. Local heat is applied to the surface of the sheet by means of a heated needle, heated type or of a warm pattern develops a green color very quickly. ■ '· "

Example 5.

30 g of 3 ~ diethylamino-6-methyl-7-p-anisidinofluoran, 4g " S-diethylamino-ö-methyl-T-dibenzylaminofluoran, 150 g j one of the above polyvinyl alcohol (the polyvinyl alcohol used is a 98% hydrolyzate) and 65 g of water are mixed together for one hour while rubbing in (component A). In addition, a component B prepared according to the method described in Example 4. Furthermore, 35 g of talc with a particle diameter becomes of 10 microns, 150 grams of polyvinyl alcohol and 65 grams of water mixed together for one hour while rubbing (Component C). s

A sheet of paper is then placed on a surface j coated with a mixture of 3 g component A, 27 g component B and 40 g component C and allowed to dry. A thin sheet of paper on which black pencil, black ink, Chinese ink, or another can be drawn Infrared rays absorbing paint material a manuscript had been written on was coated on the Side of the first sheet. The arrangement was made by a BF-11 device (a thermal copier with

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IR radiation source manufactured by Riso Kagaku Kogyo Co., Ltd. headed, taking the words or images of the said manuscript corresponding parts quickly in black color on the coated Surface of the sheet were reproduced.

Example 6

A solution of 1.0 g of 3-diethylamino-6-methyl-7-panisidinofluoran, 5 grams of dibutyl phthalate, 10 grams of castor oil, and 5 grams of chlorinated paraffin were prepared. A Rubber stamps or a wooden printing plate were moistened with the solution. Independently of this, a sheet of paper became coated on the surface with activated clay and allowed to dry. If the rubber stamp mentioned or the wood printing plate has been brought into contact with the clay-coated surface of the sheet, the words on the rubber stamp or the wooden plate very quickly turned black and green reproduced on the clay coated surface of the sheet.

Patent claims:

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Claims (1)

48 606 Applicant: NISSO ΚΑΚΟ CO., LTD. - 1-6θ, 3-Chonie, Ukima, Kita-ku, -Tokyo, Japan Fluoran derivatives Patent claims: 1. Fluoran derivatives of the general formula Γ! C = O wherein R is a lower alkoxy group in the p- or 6-position to the imino bond. 2 recording method, characterized in that that one is a fluoran derivative of general formula
C ₂ H ₅ 309830/1219 received "Λ" wherein R is a lower alkoxy group in p- or o-position to inino-birthing, brought into intimate contact with an electron accepting material, the fluoran derivative being a Lets color develop. Recording method according to Claim 2, characterized in that the fluoran derivative of the formula I corresponds to where R is a C to C »alkoxy group stands. Recording method according to one of Claims 2 or 3, characterized in that the fluoran derivative on a surface of a substrate and the electron accepting substance on a surface another carrier material. Recording method according to one of Claims 2 or 3 »characterized in that the fluoran derivative contained in microcapsules and together with the electron accepting material on a surface a carrier material is applied. Recording method according to one of Claims 2 or 3 »characterized in that the recording is carried out according to the pressure-sensitive copying process. Recording method according to one of Claims 2 or 3 »characterized in that the recording is carried out according to the thermal copying process. Dr.T / hu 309830/1219