JPH0784094B2 - Recording material - Google Patents

Description

Detailed Description of the Invention

"Industrial field of application" The present invention develops a color by contact with an electron-accepting substance such as an inorganic acid, an organic acid, a phenolic compound and their derivatives or an oxidizing agent, and has a visible region, and in some cases, a near infrared region. The present invention relates to a recording material containing a novel leuco dye having absorption in a region. "Problems to be Solved by Conventional Techniques and Inventions" As recording materials using leuco dyes, various materials such as pressure-sensitive recording materials and heat-sensitive recording materials have been conventionally known.
Due to the recent social spread of computers and the like, the demand for them tends to increase more and more in the future. Generally, what is called a pressure-sensitive recording material is basically composed of two sheets, a sheet coated with pressure-sensitive burstable microcapsules containing a solution of a leuco dye in an organic solvent and a sheet coated with an electron-accepting substance. Sheets are faced to each other, and a recording image is obtained by applying writing pressure from a ballpoint pen or the like and impact pressure from a typewriter or the like from the top of the sheet.The thermosensitive recording material is a leuco dye and an electron-accepting substance. The above-mentioned developer is mixed and coated on a support sheet, and an image is recorded by thermally applying an image signal thereto by a thermal head or the like. As described above, the pressure-sensitive
In the past, the main purpose of heat-sensitive recording materials has been to obtain a visible image. As leuco dyes that can be used for these purposes, dyes having various structures such as phthalides represented by crystal violet lactone (CVL), fluoranes having a substituted amino group, and spiropyrans have been proposed and put into practical use. CVL is often used as a typical dye for obtaining a vivid blue color, but since the light resistance of the color image is poor, it develops slowly like benzoyl leuco methylene blue (BLMB), but has good light resistance for the color image. Are used together. The dye provided by the present invention is a novel leuco dye which develops a blue to green color, which has a slow color development like BLMB but is excellent in the light fastness of a color image. BLMB has excellent lightfastness of the color image, but it tends to be gradually colored in a solution state.Therefore, when it is used for pressure-sensitive recording paper, there is no choice but to limit the amount used, and the development of a dye alternative to this. Was required. On the other hand, with the recent development of light sources such as semiconductor lasers, the development of optical character readers (OCR) has
Widely used, OCR also as a leuco dye for pressure and thermal recording
There has been a demand for leuco dyes that give a colored image having absorption not only in the visible region but also in the near-infrared region so that they can be read in such a way. Dyes / pigments having absorption in the near infrared region have been known so far, and phthalocyanine, quinacridone, and chelate compounds of other metals are well known, but since they also have large absorption in the visible region. However, it cannot be used as a dye for pressure-sensitive and heat-sensitive recording by a usual method. In order to be used for the above purpose, it is necessary to have a so-called leuco dye 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 region. For example, JP-A-51-121035, JP-A-51-121037, JP-A-51-121038, JP-A-51-167979, and JP-A-58-15.
The divinyl-containing phthalide disclosed in 7779, JP-A-60-226871, and the spirofluorenephthalide disclosed in JP-A-61-22076 are considered to be dyes that can achieve the above-mentioned object. There is. In all of these conventional proposals, a leuco dye is obtained by adding a phthalide structure to the dye structure. The present invention is a leuco dye which is completely different from these known compounds, and is usually colorless or light-colored, but it develops a color by contact with an electron-accepting substance, and some of them are in the visible region. It is also intended to provide a recording material containing a novel dye which also has absorption in the near infrared region. "Means and Actions for Solving Problems" That is, the present invention provides at least one of tetraphenyl-1,4-pentadiene compounds represented by the following general formula [1].
A recording material containing a seed as a color former. [Wherein R ¹ , R ² , R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms,
Represents a 5- or 6-membered cycloalkyl group, an arylalkyl group having 10 or less carbon atoms, or represents an alkylene group selected from ethylene, propylene and trimethylene,
In the case of an alkylene group, the other end which is not bonded to the nitrogen atom is bonded to the benzene nucleus carbon which is in the ortho position of the nitrogen atom, or R ¹
And R ^{2 at} the other end or R ³ and R ^{4 at} the other end to form a ring. Also, X, X ¹ , X ² are (R ⁵ and R ⁶ represent an alkyl group having 1 to ⁶ carbon atoms, a cycloalkyl group having 5 to 6 members, an aryl group having 10 or less carbon atoms, or an alkylene group selected from ethylene, propylene and trimethylene. In the case of an alkylene group, 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 the other ends of R ⁵ and R ⁶ are bonded to each other to form a ring.) A group selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, hydrogen, chlorine and bromine, Y ¹ and Y ² are hydrogen and 1 to 1 carbon atoms.
It represents a group selected from an alkyl group having 6 or an alkoxy group having 1 to 6 carbon atoms. Further Means that it may be a phenyl group or a naphthyl group. The compound [1] of the present invention can be regarded as a so-called leuco dye with its own colorless or pale color. This compound develops color by contacting it with an electron-accepting substance such as a phenol formalin-based resin, salicylic acid metal salts, bisphenols, attapulgite, clay minerals such as silton clay, and with an oxidizing agent such as chloranil. Color develops upon contact, in each case in the visible region of 500 nm to 700 nm, in some cases 700 nm
It forms a color image that also absorbs in the near infrared region of ~ 900 nm. Therefore, when the compound is used as a pressure-sensitive / heat-sensitive recording material, the characters and marks can be read by an optical character reader (OCR). Any route may be adopted to obtain the compound [1] of the present invention, and for example, the following reaction route can be used. Each means. The compounds [2] and [3] both belong to the 1,1-diphenylethylene derivative, and as a synthetic method, a method utilizing a Grignard reaction is generally used. (In the formula, A represents A ¹ or A ² , B represents B ¹ or B ² ,
X represents Cl, Br or I. ) In this reaction, a Grignard reagent is allowed to act on the benzophenone derivative [5], and a high-yield and high-quality ethylene derivative can be obtained very easily. In addition, an ethylene derivative having the structure of formula [6] (Wherein R ¹ and R ² are as described above) can also be obtained by the method disclosed in JP-A-61-93143. (In the formula, R ¹ and R ² are as described above) The target compound [1] is obtained by converting the ethylene derivative [2], [3] or [6] obtained as described above into water or methanol, ethanol, propanol or the like. In polar solvents such as alcohol solvents, lower alkyl substituted ethers of ethylene glycol and diethylene glycol, or cyclic ethers such as tetrahydrofuran and dioxane, mineral acids such as hydrochloric acid and sulfuric acid, fatty acids such as formic acid, acetic acid and propionic acid, and methane sulfone. It can be easily obtained by condensation with a compound [4] in the presence of an acid, an organic sulfonic acid such as P-toluenesulfonic acid, or an acid catalyst such as a benzoic acid derivative. If the same kind is used as [2], [3] or [6], a symmetric structure is obtained as [1], and if an intentional one is used, an asymmetric structure is obtained as [1]. In producing a pressure-sensitive recording material using the compound of the general formula [1], a known method can be used, for example, the core cell described in US Pat. Nos. 2,800,458 and 2,806,457. A method such as basation may be adopted. Further, in order to produce a heat-sensitive recording material, for example, a known method described in Japanese Patent Publication No. 45-14089 can be adopted. In the production of these recording materials, it is of course possible to use the compound of the general formula [1] alone, but the co-use with the conventionally known color forming compounds enhances the usefulness as a recording material. It is possible to blend with various compounds depending on the purpose. "Examples" Hereinafter, the present invention will be described in detail with reference to synthesis examples of the compound of the general formula [1] and examples of recording materials using the compound. Synthesis Example 1 To 300 cc of butanol was added 53 g of 1,1-bis (4-dimethylaminophenyl) ethylene, 12.7 g of benzaldehyde and 0.5 g of P-toluenesulfonic acid, and the mixture was reacted at 60 ° to 70 ° C. for 20 hours. Then, it was cooled and the precipitated crystals were filtered and recrystallized from toluene and ethyl acetate to give 1,1,5,5-tetrakis (4-dimethylaminophenyl) -3-phenyl-1,4-pentadiene (structural formula 25 g of pale yellow crystals of [8]) are obtained. (Mp 198 ° -204 ° C.) It slowly developed a blue-green color on silica gel and the reflection spectrum showed λ _max 650 nm. Synthesis Example 2 1- (4-Dimethylaminophenyl) -1- (4-methoxyphenyl) ethylene (26 g), benzaldehyde (5.8 g) and P-toluenesulfonic acid (2 g) were added to butanol (200 cc) and reacted at 60 ° to 70 ° C. for 30 hours. . Then, it was cooled and the precipitated crystals were filtered and recrystallized from tetrachloroethylene to give 1,5-bis (4-dimethylaminophenyl) -1,5-bis (4-methoxyphenyl) -3.
-Phenyl-1,4-pentadiene (structural formula

13 g of cream-colored crystals of [9]) are obtained. (Mp 122 ° to 127 ° C.) It slowly developed a purple-black color on silica gel, and the reflection spectrum showed λ _max 830 nm. Synthesis Example 3 1- (4-Pyrrolidinophenyl) -1- (P-tolyl) ethylene 39.3 g, 4- in 200 cc of isopropyl alcohol
Add 13.5 g of dimethylaminobenzaldehyde and 1 g of methanesulfonic acid and react at 70 ° C for 25 hours. Then, it was cooled and the precipitated crystals were filtered and recrystallized from isopropyl alcohol to give 1,5-bis (4-pyrrolidinophenyl) -1,5-bis (P-tolyl) -3- (4-dimethyl). 28 g of off-white crystals of aminophenyl) -1,4-pentadiene (structure [10]) are obtained. (M.p 147 ° -153 ° C) It slowly developed a bluish black color on silica gel, and the reflection spectrum showed λ _max 820 nm. Synthesis Examples 4 to 12 Compounds [1] synthesized in the same manner as in Synthesis Example 1 are collectively shown in the following table. Example 1 7 g of the compound obtained in Synthesis Example 2 was mixed with monoisopropylbiphenyl.
Dissolve in 98g, 24g gelatin, arabic gum 24g in this solution
A solution prepared by dissolving g in 400 cc of water and adjusting the pH to 7 was added, and the mixture was emulsified with a homogenizer. Add 1000 g of warm water to this emulsion and add 50
The mixture was stirred at 0 ° C for 30 minutes. Then dilute acetic acid is gradually added to adjust the pH to 4.
The mixture was adjusted to 5, stirred at 50 ° C for 1 hour, cooled to 0 ° to 5 ° C, and further stirred for 30 minutes. Then gradually add 85 g of 4% glutaraldehyde aqueous solution to harden the capsules, and then
The pH was adjusted to 6 with a dilute caustic soda aqueous solution and stirred at room temperature for several hours to complete encapsulation. There was no coloring phenomenon during this operation. This capsule liquid was uniformly applied to paper with a wire bar and dried to obtain capsule-coated paper (upper paper). When this paper was used as a developer and was overlaid on a paper (lower paper) coated with activated clay, and writing was performed with a ballpoint pen, a black-purple image slowly appeared on the lower paper. The image showed excellent lightfastness and showed a maximum absorption at 830 nm when the reflection spectrum was measured. Example 2 8 g of the compound obtained in Synthesis Example 3 was mixed and pulverized with 15 g of a 10% aqueous polyvinyl alcohol solution (PVA-105 manufactured by Kuraray Co., Ltd.) and 6.5 g of water in a ball mill for 20 hours to obtain “component A”.
The particle size of the dye after grinding was 3-5 microns. On the other hand, 3.5 g of bisphenol A 15 g of a 10% polyvinyl alcohol aqueous solution and 6.5 g of water are similarly mixed and pulverized by a ball mill until the particle size becomes 3 to 5 microns, and then "component B" is obtained.
And Next, 0.3 g of the component A and 6.7 g of the component B were mixed and dried, and then coated on a fine paper with a wire bar so as to have a solid content weight of 6 g / m ^2, and dried to obtain a thermosensitive recording paper. This heat-sensitive recording paper was free from fog and had a cream color and developed a color when heated with a hot pen or the like to give a reddish brown image. The image shows excellent lightfastness and the reflection spectrum shows an absorption maximum at 820 nm. "Effects of the Invention" The present invention provides a recording material which can be replaced with a conventional color recording material using benzoyl leuco methylene blue by using a completely novel tetraphenyl-1,4-pentadiene compound as a leuco dye. Is made possible.

Claims (1)

[Claims] 1. A recording material containing at least one tetraphenyl-1,4-pentadiene compound represented by the following general formula [1] as a color former. [Wherein R ¹ , R ² , R ³ and R ⁴ are alkyl groups having 1 to 6 carbon atoms,
Represents a 5- or 6-membered cycloalkyl group, an arylalkyl group having 10 or less carbon atoms, or represents an alkylene group selected from ethylene, propylene and trimethylene,
In the case of an alkylene group, the other end which is not bonded to the nitrogen atom is bonded to the benzene nucleus carbon which is in the ortho position of the nitrogen atom, or R ¹
And R ^{2 at} the other end or R ³ and R ^{4 at} the other end to form a ring. Also, X, X ¹ , X ² are (R ⁵ and R ⁶ 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 an alkylene group selected from ethylene, propylene and trimethylene. In the case of an alkylene group, 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 the other ends of R ⁵ and R ⁶ are bonded to each other to form a ring), A group selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a nitro group, hydrogen, chlorine and bromine, Y ¹ and Y ² are hydrogen and 1 to carbon atoms.
It represents a group selected from an alkyl group having 6 or an alkoxy group having 1 to 6 carbon atoms. Furthermore, Means that it may be a phenyl group or a naphthyl group. ]