JPH0643560B2 - Trivinylmethane compound and color forming recording material using the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention develops a color by bringing it into contact with an electron-accepting substance such as an inorganic acid, an organic acid, a phenolic compound and derivatives thereof, or an oxidant, and The present invention relates to a novel trivinylmethane compound having absorption in the infrared region and a color forming recording material using the compound.

[Prior Art] and [Problems to be Solved by the Invention] Recording materials using leuco dyes are
It is provided in various forms such as thermal recording paper, and the demand for it tends to increase more and more due to the recent widespread use of computers and word processors in society.
Generally, a pressure-sensitive recording material is composed of a sheet coated with pressure-sensitive burstable microcapsules containing an organic solvent solution of leuco dye and a sheet coated with an electron-accepting substance. Recording is obtained by applying writing pressure and impact pressure from the upper part of the sheet with the sheets facing each other.The heat-sensitive recording material is a mixture of a leuco dye and a color developer consisting of an electron-accepting substance, The image recording is obtained by thermally applying an image signal thereto.

Pressure sensitivity to obtain image recording by the above principle,
In the past, the main purpose of the heat-sensitive recording material was also to obtain a visible image. A phthalide compound represented by crystal violet lactone, a fluoran compound having an amino group, and the like are representative of leuco dyes, but these have a color-developing structure that absorbs only in a visible region of 700 nm or less.

However, with the recent development and spread of optical character readers, special leuco dyes for pressure and heat recording have been required. That is, the leuco dye that gives a colored image with absorption in the near infrared wavelength region is due to the development of the light source.

Dyes and pigments that have absorption in the near infrared region have been known for a long time, and phthalocyanine, quinacridone, and various other metal chelate compounds are well known, but since they also have large absorption in the visible region, There is a limitation in using it as a dye for pressure and heat-sensitive recording. In order to be used for the use, it is desirable that it is a so-called leuco type which is colorless or light in color due to its characteristics, but which can give a colored structure by contact with an electron accepting substance.

Heretofore, some proposals have been made for leuco dyes having absorption in the near infrared wavelength region. For example, JP-A-51
-121035, JP-A-51-121037, JP-A-51-121038,
The divinyl-containing phthalide disclosed in JP-A-57-167979 and the spirofluorenephthalide disclosed in JP-A-60-226871 are considered to be dyes capable of achieving this object.

All of these conventional proposals are leuco dyes by imparting a phthalide structure to the dye structure, but the present invention is a leuco dye having a trivinylmethane structure, which is completely different from these conventionally known compounds. The present invention provides a novel dye that develops color when brought into contact with an electron-accepting substance and exhibits absorption in the near infrared wavelength region.

[Means for Solving Problems] and [Action] The compound of the present invention has a structure of the following general formula [I], and as such, is usually colorless or pale and can be regarded as a so-called leuco dye.

[In the above formula, A ¹ and A ² are independent (Wherein R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 6 members, an arylalkyl group having 10 or less carbon atoms, or ethylene, propylene, Represents an alkylene group selected from trimethylene, in the case of alkylene, the other end which is not bonded to the nitrogen atom is bonded to the benzene nucleus carbon corresponding to the ortho position of the nitrogen atom or bonded at the other ends of R ¹ and R ^2. Form a ring.) A ³ is (R ¹ and R ² are as described above) represents a phenyl group which may have a substituent selected from an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and B ¹ is a hydrogen atom. A ¹
B ² represents a hydrogen atom or A ² , and B ³ represents a hydrogen atom or A ³ . Hereinafter, the same symbols have the same meaning. ].

By contacting this compound with a so-called color developer (generally an electron-accepting substance) such as a phenol-formalin resin, salicylic acid, metal salts, bisphenols, attapulgite, clay such as silton clay, etc. However, it forms a colored image that develops color and has an absorption maximum at 700 nm to 900 nm. Therefore, when the compound is used for pressure-sensitive and heat-sensitive recording paper, the characters, marks and the like can be read by an optical character reader (so-called OCR) using near infrared rays.

The compound of the present invention can be obtained, for example, by the following reaction route.

Amino-substituted diphenylethylene is a practical example of (II) and (I ′) when the reaction formula a is followed, and the simplest example is 1,1-bis (p-dimethylaminophenyl).
Ethylene may be mentioned, which can be produced from Michler's ketone through a Grignard reaction or a Wittig reaction as is known. Moreover, as the present inventors found out earlier,
It can also be obtained by oxidizing 1-bis (p-disubstituted aminophenyl) ethane with lead peroxide. As an example of (III), cinnamic aldehyde, diphenylacrolein or their nuclear substitution products can be used. Particularly useful 3,3-bis (p-disubstituted aminophenyl) among diphenylacrolein derivatives
Acrolein can be easily produced by reacting 1,1-bis (p-disubstituted aminophenyl) ethylene with Vilsmeier reagent. By reacting these with (II) and (I ') in the presence of an acid catalyst, dehydration condensation is easily achieved to obtain the target.
Generated by (I).

In the case of going through the reaction formula b, the simplest example of the intermediate of formula (IV) is bis [(p-dimethylamino) styryl] ketone obtained by condensing p-dimethylaminobenzaldehyde and acetone in the presence of an alkali. Bis [(p-dimethylamino) styryl] methanol obtained by hydrogenation can be mentioned. If this is reacted with amino-substituted diphenylethylene as an example of (II ″), dehydration condensation is performed to produce the desired (I).

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to synthesis examples of trivinylmethane compound (I) and production examples of color-forming recording materials using the same.

-Synthesis Example by Reaction Formula a- [a-1] Tris [2,2-bis (p-pyrrolidinophenyl) ethenyl] methane; 3,3-bis (p-pyrrolidinophenyl) acrolein 3,4
6g, 1,1-bis (p-pyrrolidinophenyl) ethylene 6,5
g was added to 100 ml of ethanol, 2 g of 35% hydrochloric acid was added, and the mixture was reacted at room temperature for 5 hours. Neutralize with aqueous ammonia and collect the precipitated crystals. This was recrystallized from toluene to obtain 4.2 g of pale green crystals. Melting point 195 ° C. (decomposition), this product develops color with acetic acid in methanol and exhibits absorption maximums at 610 nm and 820 nm.

[Elemental analysis]

[A-2 to 9] 1,1-bis (pyrrolidinophenyl) in [a-1]
Various 1,1-bis (p-substituted aminophenyl) ethylenes (II) and (I ') were used in place of ethylene, and various trivinylmethane compounds (I) shown in Table 1 were obtained by the same reaction. It was

[A-10 to 14] Various acrolein (III) was used instead of 3,3-bis (P-pyrrolidinophenyl) acrolein in [a-1], and various trichlorides in Table 1 were used by the same reaction. A vinylmethane compound was obtained.

-Synthesis Example by Reaction Formula b- [b-1] 3,3-Bis (p-dimethylaminostyryl) -1,1-bis (p-pyrrolidinophenyl) propene-1; Bis (p-dimethylaminostyryl) 3,2 g of methanol,
1,1-bis (p-pyrrolidinophenyl) ethylene 3.2g
Was added to 50 ml of ethyl cellosolve and reacted at 120 ° C. for 2 hours. The reaction mixture is discharged into 200 ml of water and the solid which precipitates is collected. Light blue-green crystals when recrystallized from toluene 5.
2 g are obtained. (Melting point: 109 ° C.), this product develops a strong color with acetic acid in methanol and exhibits absorption maximums at 620 nm and 790 nm.

[Elemental analysis]

[B-2 to 9] Various 1,1-bis (p-disubstituted aminophenyl) ethylene (II ″) are used instead of 1,1-bis (p-pyrrolidinophenyl) ethylene in [b-1]. In the same manner, various trivinylmethane compounds (I) shown in Table 2 were obtained.

In producing a recording material using the trivinylmethane compound (I) thus obtained, a conventionally known method may be applied. For example, U.S. Pat.
No. 2,800,458, the coacervation method described in US Pat. No. 2,800,458 can be used to produce pressure-sensitive copying paper, and the known method described in JP-B-45-14039 can be used for thermal recording. Paper can be produced.

The specific manufacturing example is shown below.

-Production Example of Pressure Sensitive Recording Paper-Part 1. 6 parts of tris [2,2-bis (p-pyrrolidinophenyl) ethenyl] methane obtained in Synthesis Example [a-1] (same as parts by weight below) were replaced with isopropyl. It is dissolved in 94 parts of biphenyl, 24 parts of gelatin and 24 parts of gum arabic are dissolved in 400 parts of water, a solution adjusted to PH7 is added, and the mixture is emulsified with a homogenizer. 1000 parts of warm water is added to this emulsion and stirred at 50 ° C for 30 minutes. Next, dilute acetic acid was gradually added to adjust the pH to 4.5 and the temperature was 50 ° C.
After stirring for 1 hour, the mixture is cooled to 0 to 5 ° C and further stirred for 30 minutes. Next, gradually add 35 parts of 4% glutaraldehyde aqueous solution to harden the capsule, and then add PH with dilute caustic soda aqueous solution.
Was adjusted to 6 and stirred at room temperature for several hours to complete encapsulation.

This capsule liquid was applied to paper and dried to obtain a capsule-coated paper (top paper). This top paper is a paper coated with phenol formalin resin as an electron-accepting developer (bottom paper).
Was recorded by overlapping writing or pressing with a typewriter so that the coated surfaces face each other to obtain a blue-green recorded image.

This recorded image has excellent light resistance and has a near infrared (λma)
x, 800 nm).

Part 2. 6 parts of 3,3-bis (p-dimethylaminostyryl) -1,1-bis (p-pyrrolidinophenyl) propene-1 obtained in Synthesis Example [b-1] was added to 94 parts of isopropylbiphenyl. Dissolve 10 of polyvinyl alcohol (polymerization degree 600)
% Aqueous solution with 100 parts of homogenizer to form an emulsion. Apply a thin coat on a neutral paper using a wire bar and air dry. When this coated surface was aligned with the upper surface (CF surface) of the lower leaf paper of various commercially available pressure-sensitive copying papers and pressure-bonded from the back side, a blue-green pressure-bonded image was obtained on the lower leaf paper. It was found from the reflection spectrum that the pressure-bonded image area had absorption in the 780-800 nm region.

Although the reaction products (I) in Synthesis Examples [a-2 to 14] and [b-2 to 9] are not necessarily isolated and purified, they are crude products containing a considerable amount of starting materials and by-products. Even if it is dissolved in a solvent and applied to the CF surface, it will develop a blue-green color.
It was confirmed that all of them were useful as inks for pressure-sensitive copying paper since they showed absorption in the vicinity of 0 nm, and were particularly suitable for infrared readers.

These trivinylmethanes are existing pressure-sensitive dyes, for example, CVL, BLMB, various fluoranes, spiropyran, indolyl phthalide, etc., there is no problem in co-use, and the coloring hue of the substance of the present invention is in the visible part. Since it is turquoise, it is important to co-use it with a black color-developing pressure-sensitive dye or a red color-developing pressure-sensitive dye especially when black is desired. In addition, there is no problem with co-use with other types of infrared color-forming dyes having different absorption wavelengths in order to have a wide suitability for various light sources of infrared readers, and known divinylphthalides, It can be used together with spirofluorene phthalides.

-Production Example of Thermosensitive Recording Paper-Part 1. 3 parts of tris [2,2-bis (p-pyrrolidinophenyl) ethenyl] methane obtained in Synthesis Example [a-1] and 10% polyvinyl alcohol (polymerization degree 600) 6.5 parts of water is added to 15 parts of the aqueous solution and mixed in a ball mill for 1 hour to obtain a dispersion (A).

3.5 parts of 2-benzyloxynaphthalene, 15 parts of 10% polyvinyl alcohol aqueous solution and 6.5 parts of water are mixed and dispersed in the same manner to obtain a dispersion liquid (B).

3.5 parts of bisphenol A, 15 parts of 10% polyvinyl alcohol aqueous solution and 6.5 parts of water are similarly mixed and dispersed to obtain a dispersion (C).

1 part of the dispersion liquid (A) and 10 parts of each of the dispersion liquids (B) and (C) were mixed well, thinly coated on a neutral paper with a wire bar, and air-dried to obtain a thermosensitive recording paper.

This thermal recording paper developed a bluish green color at a temperature of 100 ° C. or higher in the hot plate compression test. In addition, good color development was exhibited by recording using a thermal head. The reflectance spectrum measurement of the color image shows absorption at about 800 nm, indicating that infrared reading is possible.

Part 2. Since the visible image of the above thermal paper is blue-green, a commercially available pressure-sensitive dye was blended as follows in order to make the visible image black.

2-anilino-3-methyl-6- (N-ethyl-N-isopentylamino) fluorane (black coloring) 3 parts, 9-diethylamino-benzo [a] fluorane (red coloring) 0.
5 parts, 15 parts of a 10% polyvinyl alcohol aqueous solution, and 6.5 parts of water are mixed and dispersed by a ball mill to obtain a dispersion liquid (D).

Dispersion (A) 1 part, Dispersion (D) 1 part, Dispersion (B) and (C) each
Mix 10 parts well, apply thinly on a neutral paper with a wire bar and air dry. The heat-sensitive recording paper thus obtained develops color well as in the above example, and the visible image becomes black. And about 800 nm
The infrared reading is possible by showing the absorption at.

〔The invention's effect〕

As described above, the present invention has succeeded in creating a novel compound. This novel compound is useful as a color former for recording materials, has a trivinylmethane structure not found in conventional dyes, and is characterized as exhibiting absorption in the near infrared wavelength region.

Claims (2)

[Claims] 1. A general formula A trivinylmethane compound represented by. [In the formula, A ¹ and A ² are independently (Wherein R ¹ and R ² independently represent an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 6 membered rings, an arylalkyl group having 10 or less carbon atoms, or ethylene, propylene, Represents an alkylene group selected from trimethylene, and in the case of alkylene, the other end not bonded to the nitrogen atom is bonded to the benzene nucleus carbon corresponding to the ortho position of the nitrogen atom, or is bonded to the other end of R ¹ and R ² to form a ring. A ³ is formed. (R ¹ and R ² are as described above), represents a phenyl group which may have a substituent selected from an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and B ¹ is a hydrogen atom. A
¹ , B ² is a hydrogen atom or A ² , and B ³ is a hydrogen atom or A ³
Represents ]. 2. A color-forming recording material containing a trivinylmethane compound represented by the general formula [I] as a color-developing agent. [In the above formula, A ¹ and A ² are independently (Wherein R ¹ and R ² independently represent an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 5 to 6 membered rings, an arylalkyl group having 10 or less carbon atoms, or ethylene, propylene, Represents an alkylene group selected from trimethylene, and in the case of alkylene, the other end not bonded to the nitrogen atom is bonded to the benzene nucleus carbon corresponding to the ortho position of the nitrogen atom, or is bonded to the other end of R ¹ and R ² to form a ring. A ³ is formed. (R ¹ and R ² are as described above) represents a phenyl group which may have a substituent selected from an alkyl group having 1 to 6 carbon atoms and an alkoxy group having 1 to 6 carbon atoms, and B ¹ is a hydrogen atom. A
¹ , B ² is a hydrogen atom or A ² , and B ³ is a hydrogen atom or A ³
Represents ].