JPH01168681A - Crystal modification 3,3-bis(2,2-bis(p-dimethylaminophenyl) ethenyl)-4,5,6,7-tetrabromophthalide and chromic recording medium using said modification - Google Patents

Abstract

NEW MATERIAL:A crystal modification of a compound expressed by formula I, which has strong peaks at angles of diffraction (2theta) of 7.8, 15.8, 21.8 and 23.8 in X-ray diffraction method with Cu-Ka radiation. USE:A chromophore of a chromic recording medium. PREPARATION:One mol tetrabromphthalic anhydride expressed by formula II is reacted with 2mol 1,1-bis(p-dimethylaminophenyl)ethylene expressed by formula III in the presence of a condensing and dehydrating agent such as acetic anhydride at 50-100 deg.C for several hours. Then after cooling to 10-20 deg.C, precipitates are filtered off and dissolved in a mixed solvent of an alkaline aqueous solution such as sodium hydroxide with an organic solvent such as toluene at 80-90 deg.C. Then the organic solvent layer is concentrated to crystallize an alpha-type crystal, which is then dissolved in chloroform in an amount of 5-10 times, etc. After mixing, a crystal is precipitated to afford the beta-type modification.

Description

[Detailed Description of the Invention] [Field of Industrial Application] In recent years, OCR (Optical Character Reader) has come to be frequently used as a human-powered medium for computers, and in the fields of pressure-sensitive copying paper and thermal recording paper, near-red A recording material having absorption in the outer region is strongly desired. Pressure-sensitive copying paper and heat-sensitive recording paper have long been widely used as paper that utilizes the property of producing color by bringing an electron-accepting substance (developer), which itself is almost colorless, into contact with an electron-donating substance (color-forming agent).
Are known. In particular, the 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5 of the present invention
, 6,7-tetrabromophthalide has strong absorption in the near-infrared region, and can be used as a color former for commonly used pressure-sensitive copying paper and heat-sensitive recording paper, as well as for OCR. It is extremely useful as a coloring agent for pressure-sensitive copying paper and heat-sensitive recording paper.

[Prior art] and [Problems to be solved by the invention] When a color forming agent that absorbs in the near-infrared region is used in pressure-sensitive copying paper, the color development property, color density, and color image in the near-infrared region are When used in thermal recording paper, it is required to have excellent color development sensitivity in the near-infrared region, color development property, stability of the color image, and light resistance of the background. There is no color former that satisfies all the properties.

For example, 3,6.6°-
Tris(dimethylamino)fluorene spiro(9,3)
Tsukurido (Japanese Unexamined Patent Publication No. 59-199757) has extremely low solubility in solvents for pressure-sensitive copying paper, and is significantly lacking in coloring sensitivity, coloring density, and light fastness of colored images in the near-infrared region. 3,3-bis[2,2
-bis(p-dimethylaminophenyl)ethenyl]-4
, 5,6,7-tetrachlorophthalide (Special Publication No. 58-5
940) is relatively good in color development sensitivity, color density, and stability of color images in the near-infrared region, but it is significantly inferior in light resistance of the background (crystals turn reddish-brown due to sunlight irradiation, and (disassemble) has drawbacks.

Means for Solving Problem C] The present inventors have developed a product which improves these shortcomings and has excellent color development in the near-infrared region, color development sensitivity, color density, stability of color image, light fastness of the background, etc. As a result of intensive studies to develop a color former, we found that there are two types of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethynyl]-4,5,6,7-tetrabromophthalide. We discovered that crystal transformations exist.

In other words, the coloring sensitivity and density in the near-infrared region are extremely low (and the light resistance of the background is extremely poor). There are two types: crystal modification M (hereinafter referred to as β-type modification), which has a high concentration, almost no discoloration or decomposition of crystals due to sunlight irradiation, and has extremely excellent light resistance of the skin.

Comparing the α-type transformation and the β-type transformation in terms of the X-ray diffraction state of α-rays on Cu-, the α-type transformation has a diffraction angle (2θ) of 6.3.8.3.16 as shown in Figure 2. .6°24.5
The β-type transformation has a strong peak at the diffraction angle (2θ) 7.8.15.8.21.8.23 as shown in Figure 1.
It has a strong peak at °8, and the β-type transformation is clearly α
It shows the type transformation and different peaks in the X-ray diffraction diagram.

Whether the α-type modification was converted to the β-type modification in Synthesis Examples 1 and 2 described later, or whether the crystal obtained in Synthesis Example 3 is the β-type modification can be determined by measuring the X-ray diffraction pattern. However, it can also be determined by measuring the melting point of the crystal.

That is, the α-type transformation ranges from 255 to 258°C, while the β-type transformation ranges from 271 to 273°C, and can be clearly distinguished. Furthermore, as an easier method, determination can also be made by comparing the degree of discoloration of crystals due to irradiation with sunlight or ultraviolet rays. That is,
The α-type metamorphosis quickly changes color to reddish brown, but the β-type metamorphosis hardly changes color.

3.3-bis(2,
2-bis(p-dimethylaminophenyl)ethenyl]-
Among 4,5,6,7-tetrabromophthalide (3), the α-type modification can be synthesized by a known method (Japanese Patent Publication No. 58-5940).

That is, 1 mol of tetrabromophthalic anhydride (1) and 1.1
-bis(p-dimethylaminophenyl)ethylene (2)
2 mol and 50 to 1 mol in the presence of a condensation dehydrating agent such as acetic anhydride.
After reacting at 00°C for several hours and then cooling to 10-20'C, the precipitate was filtered out and dissolved in a mixed solution of an aqueous alkaline solution such as sodium hydroxide and an organic solvent such as toluene.
Melts at 0-90°C. Next, the organic solvent layer is concentrated to precipitate crystals.

3rIf CH2Br On the other hand, to synthesize the β-type modification, the α-type modification obtained as described above is dissolved or mixed with 5 to 10 times the amount of chloroform, dichloromethane, or other chloroalkane, and then crystals are precipitated. The precipitate is mixed in a mixed solution of the alkaline aqueous solution and the chloroalkane, and after extraction, crystals are precipitated in an organic solvent layer.

3,3-bis[2,2-bis(
p-dimethylaminophenyl)ethynyl]-4,5,6
, 7-tetrabromophthalide may contain the above-mentioned organic solvent as a crystallizing solvent, and it itself has a slightly yellow color and is used as a solvent for pressure-sensitive copying paper, such as diarylethane, alkylnaphthalene, and hydrogenated terphenyl. , dissolved in alkylbiphenyl, color developer such as organic acid, acid clay,
It quickly turns blue-green by contacting it with a color developer such as phenol-formalin resin or metal salt of aromatic carboxylic acid, or heating and melting it with a color developer such as bisphenol A1 bisphenol 5Sp-hydroxybenzoic acid benzyl ester. It develops color and exhibits strong absorption in the near-infrared region.

The colored images have high color density and strong photostability, and the crystals themselves hardly discolor or decompose due to sunlight irradiation, and when made into thermal recording paper, the background has excellent light resistance.

Further, the β-type modification of 3.3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide of the present invention can be used with other color formers such as 3.
3-bis(4-dimethylaminophenyl)-6-dimethylaminophthalide, disubstituted fluoran compounds such as British Patent No. 1182743, Belgian Patent No. 815
No. 291, No. 815,294, and bisindolylphthalide compounds such as those described in German Patent Publication No. 2,259,711.

[Action and effect of invention]

3,3-bis[2,2-bis(p-dimethylaminophenyl)ethynyl] of the present invention 4.5,6. It has been shown that the β-type modification (A) of fuchtrabromphthalide exhibits extremely excellent properties as a coloring agent with absorption in the near-infrared region, as well as the α-type modification (B) of the same compound and the known compound 3. 3-
Bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrachlorophthalide (
C) (described in Japanese Patent Publication No. 58-5940).

(1) Color-forming comparative compounds (A), (B), and (C) were made into thermal paper by the method of Production Example 2 described below. The color density was measured using a Shimadzu spectrophotometer UV-365 at a wavelength of 900 nm.

B. Static coloring properties Heating time: 1 second Pressure: 1, 5 kg/cTA
Table 1 0, dynamic color development characteristic voltage 16V Table 2 As shown in Tables 1 and 2, Compound (A) has a higher degree of discoloration at low temperatures than Compounds (B) and (C).
It also has excellent heat-sensitive properties. This shows that a highly sensitive thermal paper with high color development can be obtained.

(2) Comparative light resistance of background Compounds (A), (B) and (C) were prepared into thermal paper in the same manner as in (2) above.

B. Discoloration of the background The thermal paper of compounds (A), (B) and (C) was irradiated with sunlight, and the degree of discoloration of the background was measured by time using Macbeth RD-514.
Measured using a reflection densitometer.

Decomposition degree of the mouth and skin The heat-sensitive paper of compounds (A), (B) and (C) was irradiated with sunlight, and the color density was measured over time using a Shimadzu spectrophotometer UV-365.
It was measured at a wavelength of 900 nm.

Heating time 1 second Pressure 1.5) cg/a Heating temperature
140° C. Table 4 As shown in Tables 3 and 4, Compound (A) causes almost no discoloration of the background compared to Compounds (B) and (C), and the decrease in color density is extremely small.

This shows that a thermal paper with excellent light resistance can be obtained.

[Examples, etc.]

Next, the synthesis method of the α-type modification and β-type modification of 3.3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide of the present invention will be described. A specific example will be given.

Reference Example 1 (Synthesis according to Japanese Patent Publication No. 5B-5940) 46.4 g of tetrabromophthalic anhydride and 51.3 g of 1,1-bis(p-dimethylaminophenyl)ethylene were heated at 400 mA of acetic anhydride! The mixture was reacted for 1 hour at 74°C. Cool to 20°C, filter out the precipitate, add to 1200ml of toluene,
The mixture was heated and dissolved at 00 to 110°C. Cool the toluene solution and add 700m of petroleum ether! ! , added. The precipitate was filtered and dried to give 65 g of pale yellow crystals with a melting point of 255-258°C.
I got it.

This is the α-type modification of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide, and its X-ray diffraction pattern is shown in Figure 2. Indicated.

Synthesis Example 1 20 g of α-modified 3.3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide of Reference Example 1 was dissolved in chloroform 20 g.
0m! ! , and mixed for 1 hour at 60°C. Next, chloroform was distilled off and the precipitate was filtered and dried to a melting point of 27.
19 g of yellow crystals with a temperature of 5 to 273°C were obtained.

This is a β-type modification of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide, and the X-ray diffraction diagram shown in Figure 1 showed that.

Synthesis Example 2 Chloroform 200mI! , dichloromethane 200m
The same operation as in Synthesis Example 1 was carried out except that 1 was used to obtain 19 g of yellow crystals with a melting point of 271 to 273°C.

This is the β-type modification of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide, and the same X-ray as shown in Figure 1 The diffraction diagram is shown.

Synthesis Example 3 The precipitate obtained by reacting in the same manner as in Reference Example 1 was mixed with 10,100 O of dichloromethane and 500 O of a 5% aqueous sodium hydroxide solution.
ml and heated to 90°C.

The tetrachloroethane layer was concentrated, and the precipitate was filtered off and dried to obtain 68 g of yellow crystals with a melting point of 275-273°C.

This is the β-type modification of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide, and the same X A line diffraction diagram is shown.

Next, 3, 3 obtained by operating in exactly the same manner as in Synthesis Example 1 except that the organic solvent used in Synthesis Example 1 was replaced with another organic solvent.
-Bis[2,2-bis(p-dimethylaminophenyl)
Table 5 shows the types of crystal modifications of [ethenyl]-4,5,6,7-tetrabromophthalide.

Table 5 Pressure-sensitive copying paper is produced using the β-type modification of these 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide. There are known methods for producing heat-sensitive recording paper, such as those described in U.S. Pat. No. 2,800,458 and U.S. Pat. There is a method described. Examples of manufacturing pressure-sensitive copying paper and heat-sensitive recording paper are shown below.

Production Example 1 (Preparation Example of Pressure Sensitive Copying Paper) Synthesis Example 1 of 3,3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide β-type modification 7 parts (hereinafter shown in parts by weight)
is dissolved in 93 parts of monoisopropylbiphenyl, and a solution prepared by dissolving 24 parts of gelatin and 24 parts of gum arabic in 400 parts of water and adjusting the pH to 7 is added to this solution. Next, emulsify with a homogenizer, add 1000 parts of warm water, stir at 50°C for 30 minutes, add about 1 part of 10% caustic soda solution, and stir at 50°C for 30 minutes.Next, add acetic acid seed. The pH was adjusted to 465, stirred at 50°C for about 1 hour, cooled to 0-5°C, and further stirred for 30 minutes. Next 4
% glutaraldehyde aqueous solution was added to harden the capsules, the pH was adjusted to 6 with a dilute caustic soda aqueous solution, and the encapsulation was completed by stirring at room temperature for several hours. This capsule liquid was uniformly applied to paper using a wire bar and dried to obtain capsule-coated paper (upper paper). This paper is coated with acid clay or phenol-formalin resin as a color developer.
When the pressure of a superimposed ballpoint pen or the impact of a typewriter was applied to the lower paper, a dark blue-green image quickly appeared on the lower paper. This image had strong absorption in the near-external region and exhibited excellent light resistance.

Production Example 2 (Production Example of Heat-sensitive Recording Paper) 3,3-bis[2,2-bis(P-dimethylaminophenyl)ethenyl] -4,5,6,7-5- of Synthesis Example 1
5 parts of β-type modification of trabromophthalide, 15 parts of kaolin,
100 parts of 10% polyvinyl alcohol aqueous solution, 85 parts of water
A portion was ground in a paint shaker (manufactured by Toyo Seiki Co., Ltd.) until the average particle diameter was 2 microns to obtain Liquid A. In another method, 15 parts of bisphenol A, 10 parts of zinc stearate, 20 parts of stearamide, and 150 parts of a 10% polyvinyl alcohol aqueous solution were ground in the same manner until the average particle size was 3 microns to obtain liquid B. Next, add 10 parts of liquid A and 6.5 parts of liquid B.
Mix the parts and use a wire bar to reduce the solid content to 5g/rrK.
The mixture was coated uniformly on high-quality paper and dried to obtain heat-sensitive recording paper. This thermosensitive recording paper quickly developed a blue-green color when heated with a thermal pen or the like, had strong absorption in the near-infrared region, had almost no discoloration of the background, and exhibited excellent light resistance in the background and colored images.

[Brief explanation of the drawing]

Figure 1 shows the X-ray diffraction diagram of the β-type modification of 3.3-bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide, and Figure 2 is an X-ray diffraction diagram of the α-type modification of the same compound. Figure 1: 0.00 Km (20) Procedural dispute official document (spontaneous)

Claims (2)

[Claims] (1) In the X-ray diffraction method using Cu-Kα rays, it is characterized by an X-ray diffraction diagram showing strong peaks at diffraction angles (2θ) of 7.8, 15.8, 21.8, and 23.8. −
Crystal modification of bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide. (2) In the X-ray diffraction method using Cu-Kα rays, it is characterized by an X-ray diffraction diagram showing strong peaks at diffraction angles (2θ) of 7.8, 15.8, 23.8, and 23.8. −
A color-forming recording material characterized by containing a crystal modification of bis[2,2-bis(p-dimethylaminophenyl)ethenyl]-4,5,6,7-tetrabromophthalide as a color former.