JPH09124654A - Reverse photochromic compound and reversible recording medium using the same, and reversible recording - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above new compound excellent in contrast in its color development and color fading and in the repeated durability of reversible color development/color fading and light resistance, thus useful for reversible recording media such as copying materials and facsimiles. SOLUTION: This new compound is a spiropyran derivative of formula I (R1 is a 1-11C alkyl, 1-20C aryl, 1-6C methylene chain-bearing methacryloxy, etc.; R2 -R5 are each H, an alkyl, hydroxyl, amino, alkylamino, nitro, halogen, alkoxyl, cyano, etc., but all of them being not H). The compound of formula I is e.g. a spiropyran derivative of formula II which is obtained by refluxing under heating for 5h 1,3,3-trimethyl-2-methylene-5-methoxyindoline and 3,5- dinitrosalicylaldehyde in ethanol.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a reversible recording material which develops color by heat and is erased by irradiation of visible light. In particular, the reversible recording material is excellent in contrast between color development and erasure and is reversible. The present invention relates to an inverse photochromic compound excellent in repeated durability of coloring and decoloring and light resistance, a reversible recording medium using the same, and a reversible information recording method.

[0002]

2. Description of the Related Art In recent years, the amount of paper used as a medium for recording and displaying information such as characters and images has continued to increase. Recycling is essential. A rewritable recording medium is expected as one of the solutions. As a rewritable recording medium, there is a recording medium using a reversible thermosensitive recording material, and a physical change using a reversible thermosensitive recording material in which the refractive index and the light scattering property change due to phase separation or phase change due to heat. There are a type and a chemical change type using a reversible thermosensitive recording material whose structure is changed by heat and its phase is changed in color. The physical change type can be further divided into crystalline polymer type, polymer liquid crystal type, polymer blend type, polymer / liquid crystal type, polymer / low molecular type and the like.

[0003]

A polymer / low molecular weight type reversible thermosensitive recording medium, which is a typical example of a physical change type, has a recording layer made of a reversible thermosensitive recording material formed on a transparent polyester base film. The recording layer is provided with a protective layer. In this recording medium, recording is performed by a thermal head and erasing is performed by a heat roller or a heat stamp. According to this high-molecular / low-molecular type reversible thermosensitive recording medium, recording can be performed with almost the same energy as thermal paper. However, since information is recorded by utilizing the difference between the cloudy state and the transparent state in the recording layer, there is a drawback that the contrast is not so good. On the other hand, a reversible thermosensitive recording medium that uses a leuco dye whose lactone ring is opened and closed by heat, which is a typical example of a chemical change type, uses a leuco dye (color former), which is a basic dye, and an acidic dye. The substance contains an electron-withdrawing phenolic compound (developing agent), and the protons dissociated from the developing agent by thermal energy ring-open the colorless leuco body to develop color as a triphenylmethane dye, which is a base. It is deprotonated and decolorized by contact with a volatile substance. However, there are disadvantages that the reversibility of reversible color development / decolorization is poor and the light resistance is not sufficient.

The present invention has been made in view of the above-mentioned problems, and has a novel contrast which is excellent in the contrast between the time of color development and the time of color erasure, and is also excellent in the reversibility of reversible color development / decolorization and the light resistance. Another object of the present invention is to provide a reverse photochromic compound, a reversible recording medium using the same, and a reversible recording method using the reversible recording medium.

[0005]

The inverse photochromic compound according to the present invention comprises a spiropyran derivative represented by the above formula (Formula 1). However, in the above formula (Formula 1), R 1 is an alkyl group having 1 to 11 carbon atoms, an aryl group having 1 to 20 carbon atoms, or 1 to 6 carbon atoms.
Which is a methacryloxy group having a methylene chain and a methacrylamide group having a methylene chain having 1 to 6 carbon atoms, wherein R2, R3, R4 and R5 are each a hydrogen atom, an alkyl group or a hydroxy group, Any one of an amino group, an alkylamino group, a nitro group, a halogen group, an alkoxy group, a cyano group, a carbonyl group, a carboxyl group, an alkoxycarbonyl group, and a benzo group, R2,
At least one of R3, R4, and R5 is any of the aforementioned substituents.

Further, the reversible recording medium according to the present invention is
A recording layer is formed by introducing the above-mentioned reverse photochromic compound into a polymer side chain or dispersing it in a polymer on a support.

Further, in the reversible information recording method according to the present invention, the recorded information is recorded by recording information on the recording layer of the reversible recording medium by a thermal recording means and irradiating the recording layer with visible light. Is reversibly erased.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The inverse photochromic compound of the present invention comprises a spiropyran derivative represented by the above-mentioned formula (formula 1), and as shown in the following chemical formula (formula 2), the spiropyran compound is heated by heat. Changes its structure (becomes a colored species merocyanine type) and changes from a colorless state to a colored state, and upon irradiation with visible light, its spiropyran reversibly changes to its original structure (the colored species merocyanine type is a reverse isomer). Then, the colored state changes to a colorless state. The contrast in the state change from the colorless state to the colored state or from the colored state to the colorless state is good, and further, the characteristic deterioration is small even in the repeated state change from the colorless state to the colored state and from the colored state to the colorless state, and The characteristics are not deteriorated even by irradiation with visible light. Further, the hue can be changed at the time of color development by changing the kind of the substituent constituting the derivative, and it is possible to cope with colorization.

[0009]

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Further, according to the reversible recording medium of the present invention,
Since the recording layer formed by introducing the above-mentioned inverse photochromic compound into the polymer side chain or dispersing it in the polymer is formed on a sheet-like support, information can be recorded with good contrast and further, Rewriting can be performed repeatedly and stably. Also, it can be easily manufactured.

As a preferred example of the above structure, when the recording layer is covered with a protective layer made of a heat resistant transparent resin,
The recording layer is protected from heat and mechanical shock, and the durability of the recording medium is improved.

Further, as a preferred example of the above-mentioned constitution, when an ultraviolet absorber is dispersed in the protective layer, the incidence of light other than visible light on the recording layer is suppressed, and only the reverse of heat and visible light irradiation occurs. Photochromism is effectively retained, and the reliability of the recording medium is improved.

Further, according to the reversible recording method of the present invention,
Information is recorded on the recording layer of the reversible recording medium by a thermal recording means, and the recorded information is reversibly erased by irradiating the recording layer with visible light. Can be rewritten repeatedly.

In the present invention, the form of the support constituting the reversible recording medium is not particularly limited, but a sheet-like one is generally used. As the constituent material of the support, a conventionally known heat-resistant resin can be used, for example, polyethylene terephthalate resin, epoxy resin,
Examples thereof include polyimide resin and polyamide resin. Further, as the binder polymer constituting the recording layer, butyral resin, polymethylmethacrylate, polystyrene or the like can be used. The recording layer is formed by introducing an inverse photochromic compound into the side chain of the polymer during or after the synthesis of these polymers, or by mechanically dispersing the inverse photochromic compound in these polymers. It is performed by forming a film on the top. The protective layer that covers the recording layer is formed by forming a heat-resistant transparent resin known per se, such as a silicon-based transparent resin, on the recording layer. Further, as the ultraviolet absorber added to the recording layer, for example, Ciasorb UV-5
411 (manufactured by Nippon Cyanamid Co., Ltd.), Ubinal (manufactured by BASF Japan Co., Ltd.) and the like, which are known materials having an ultraviolet absorbing action, can be used.

[0015]

【Example】

Example 1 Synthesis of Spiropyran Derivative (SP1) 3.2 g (15.7 mmol) of 1,3,3-trimethyl-2-methylene-5-methoxyindoline (1) and 3,5-dinitrosalicylaldehyde (2) 3.3 g (15.7 mmol) was heated under reflux in 35 ml of ethanol for 5 hours to carry out the reaction represented by the following reaction formula (Formula 3).

[0016]

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The obtained reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 5.7 g (yield 92%) of spiropyran derivative (SP1). The following are the physical properties of the obtained spiropyran derivative (SP1).

Melting point 259-260 ° C Molecular weight measurement (EI) m / z 397 (M ⁺ ), molecular weight 397.32 Elemental analysis value Calculated as C ₂₀ H ₁₉ N ₃ O ₆ C, 60.45% H, 4.82% N, 10.58% Measured value C, 60.23% H, 4.80% N, 10.47% IR (KBr) ν 1612, 1548, 1466, 1437, 1283, 1242, 122
3, 1073, 822, 745 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP1) has the formula (Formula 1) in which R1 is a methyl group, R2, R4 and R5 are hydrogen atoms, and R3 is R3. Was confirmed to consist of a methoxy group.

(Example 2) Synthesis of spiropyran derivative (SP2) 1,3,3,5-tetramethyl-2-methyleneindoline (3) 3.0
g (16.0 mmol) and 3,5-dinitrosalicylaldehyde (2)
3.4 g (16.0 mmol) was heated and refluxed in 35 ml of ethanol for 5 hours to carry out the reaction represented by the following reaction formula (Formula 4).

[0020]

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The obtained reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 5.5 g of spiropyran derivative (SP2) (yield 90%). The following are the physical properties of the obtained spiropyran derivative (SP2).

Melting point 279-280 ° C Molecular weight measurement (EI) m / z 381 (M ⁺ ), molecular weight 381.33 Elemental analysis value Calculated as C ₂₀ H ₁₉ N ₃ O ₅ C, 62.99% H, 5.02% N, 11.02% Measured value C, 62.82% H, 5.00% N, 10.93% IR (KBr) ν 1612, 1530, 1465, 1441, 1301, 1216, 109
2, 1040, 811, 742 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP2) is a compound represented by the above formula (Formula 1) in which R1 and R3 are methyl groups, and R2, R4 and R5 are hydrogen atoms. It was confirmed to consist of.

Example 3 Synthesis of Spiropyran Derivative (SP3) 4.0 g (15.9 mmol) of 1,3,3-trimethyl-2-methylene-5-bromoindoline (4) and 3,5-dinitrosalicylaldehyde (2) ) 3.4 g (15.9 mmol) was heated and refluxed in 45 ml of ethanol for 5 hours to carry out the reaction represented by the following reaction formula (Formula 5).

[0024]

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The obtained reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 6.4 g (yield 90%) of spiropyran derivative (SP3). The following are the physical properties of the obtained spiropyran derivative (SP3).

Melting point 297-298 ° C. Molecular weight measurement (EI) m / z 445 (M ⁺ ), molecular weight 446.20 Elemental analysis value C ₁₉ H ₁₆ BrN ₃ O ₅ Calculated value C, 51.14% H, 3.61% N, 9.42% Measured value C, 51.01% H, 3.58% N, 9.31% IR (KBr) ν 1612, 1529, 1464, 1440, 1302, 1212, 109
3, 1039, 811, 733 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP3) has the formula (Formula 1) in which R 1 is a methyl group, R 2, R 4 and R 5 are hydrogen atoms, It was confirmed that R3 was a bromo group.

Example 4 Synthesis of Spiropyran Derivative (SP4) 2.0 g (10.5 mmol) of 1,3,3-trimethyl-2-methylene-5-fluoroindoline (5) and 3,5-dinitrosalicylaldehyde (2) ) 2.2 g (10.5 mmol) was heated and refluxed in 30 ml of ethanol for 4 hours to carry out the reaction represented by the following reaction formula (Formula 6).

[0028]

[Chemical 6]

The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 3.6 g of spiropyran derivative (SP4) (yield 90%). The following are the physical properties of the obtained spiropyran derivative (SP4).

Melting point 290-291 ° C. Molecular weight measurement (EI) m / z 385 (M ⁺ ), molecular weight 385.30 Elemental analysis value C ₁₉ H ₁₆ FN ₃ O ₅ Calculated value C, 59.22% H, 4.19% N, 10.91% Measured value C, 59.08% H, 4.05% N, 10.68% IR (KBr) ν 1616, 1528, 1464, 1444, 1295, 1250, 108
4,1042 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP4) is the same as in the above-mentioned formula (Formula 1), wherein R1 is a methyl group, R2, R4 and R5 are hydrogen atoms, and R3 is fluoro. It was confirmed to be the base.

(Example 5) Synthesis of spiropyran derivative (SP5) 2.6 g (7.9 mmol) of 1,3,3-trimethyl-2-methylene-5,7-dibromoindoline (6) and 3,5-dinitrosalicylaldehyde (2) 1.7 g (7.9 mmol) was heated and refluxed in 35 ml of ethanol for 5 hours to carry out the reaction represented by the following reaction formula (Formula 7).

[0032]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 3.5 g of spiropyran derivative (SP5) (yield 85%). The following are the physical properties of the obtained spiropyran derivative (SP5).

Melting point 232-233 ° C. Molecular weight measurement (EI) m / z (M ⁺ ), molecular weight 525.09 Elemental analysis value Calculated value as C ₁₉ H ₁₅ Br ₂ N ₃ O ₅ C, 43.46% H, 2.88% N, 8.00 % Measured C, 43.28% H, 2.83% N, 7.88% IR (KBr) ν 1607, 1534, 1459, 1437, 1305, 1212, 108
9, 1034, 862, 741 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP5) is a compound represented by the formula (Formula 1) in which R1 is a methyl group, R2 and R4 are hydrogen atoms, R3, It was confirmed that R5 was a bromo group.

(Example 6) Synthesis of spiropyran derivative (SP6) 1.4 g (7.2 mmol) of 1,3,3-trimethyl-2-methylene-5,7-difluoroindoline (7) and 3,5-dinitrosalicylaldehyde (2) 1.5 g (7.2 mmol) was heated and refluxed in 30 ml of ethanol for 3 hours to carry out the reaction represented by the following reaction formula (Formula 8).

[0036]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 2.6 g of spiropyran derivative (SP6) (yield 88%). The following are the physical properties of the obtained spiropyran derivative (SP6).

Melting point 220-221 ° C. Molecular weight measurement (EI) m / z 403 (M ⁺ ), molecular weight 403.29 Elemental analysis value C ₁₉ H ₁₅ F ₂ N ₃ O ₅ Calculated value C, 56.58% H, 3.75% N, 10.42% Actual value C, 56.39% H, 3.70% N, 10.22% IR (KBr) ν 1616, 1530, 1466, 1434, 1305, 1241, 108
9,1044,861,747 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP6) is the same as in the above formula (Formula 1), wherein R1 is a methyl group, R2 and R4 are hydrogen atoms, R3 and R5. Was confirmed to be a fluoro group.

(Example 7) Synthesis of spiropyran derivative (SP7) 1,3,3,5,7-pentamethyl-2-methyleneindoline (8)
1.5 g (7.5 mmol) and 3,5-dinitrosalicylaldehyde (2) 1.6 g (7.5 mmol) were heated and refluxed in 30 ml of ethanol for 4 hours to carry out the reaction represented by the following reaction formula (Formula 9). .

[0040]

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After the reaction mixture was cooled and filtered, recrystallization with ethanol was repeated 3 times to obtain 2.7 g (yield 92%) of the spiropyran derivative (SP7). The following are the physical properties of the obtained spiropyran derivative (SP7).

Melting point 263 to 264 ° C. Molecular weight measurement (EI) m / z 395 (M ⁺ ), molecular weight 395.36 Elemental analysis value Calculated as C ₂₁ H ₂₁ N ₃ O ₅ C, 63.79% H, 5.35% N, 10.63% Measured value C, 63.70% H, 5.31% N, 10.43% IR (KBr) ν 1615, 1530, 1450, 1446, 1290, 1214, 108
4, 1042, 858, 747 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP7) is a compound of the above formula (Formula 1) in which R1 is a methyl group, R2 and R4 are hydrogen atoms, R3, It was confirmed that R5 was a methyl group.

Example 8 Synthesis of Spiropyran Derivative (SP8) 1.8 g (7.4 mmol) of 1,3,3-trimethyl-2-methylene-4,6-dichloroindoline (9) and 3,5-dinitrosalicylaldehyde (2) 1.6 g (7.4 mmol) was heated and refluxed in 30 ml of ethanol for 3 hours to carry out the reaction represented by the following reaction formula (Formula 10).

[0044]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 2.7 g of spiropyran derivative (SP8) (yield 85%). The following are the physical properties of the obtained spiropyran derivative (SP8).

Melting point 269 to 270 ° C. Molecular weight measurement (FD) m / z 436 [(M + H) ⁺ ], molecular weight 436.19 Elemental analysis value Calculated value as C ₁₉ H ₁₅ Cl ₂ N ₃ O ₅ C, 52.31% H, 3.47% N, 9.64% Measured C, 52.25% H, 3.44% N, 9.39% IR (KBr) ν 1622, 1528, 1467, 1436, 1311, 1216, 109
The spiropyran derivative (SP8) obtained by 3 cm ⁻¹ elemental analysis and IR (KBr) analysis is a compound of the above formula (Formula 1) in which R 1 is a methyl group, R 2 and R 4 are chloro groups, and R 3 and R 5 are hydrogen atoms. I confirmed that there is something.

Example 9 Synthesis of Spiropyran Derivative (SP9) 1,3,3,4,6-pentamethyl-2-methyleneindoline (1
0) 1.5 g (7.5 mmol) and 3,5-dinitrosalicylaldehyde (2) 1.6 g (7.5 mmol) were heated to reflux in 35 ml of ethanol for 3 hours to carry out the reaction represented by the following reaction formula (Formula 11). went.

[0048]

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After the reaction mixture was cooled and filtered, recrystallization with ethanol was repeated 3 times to obtain 2.6 g of spiropyran derivative (SP9) (yield 87%). The following are the physical properties of the obtained spiropyran derivative (SP9).

Melting point 268-269 ° C. Molecular weight measurement (EI) m / z 395 (M ⁺ ), molecular weight 395.36 Elemental analysis value Calculated as C ₂₁ H ₂₁ N ₃ O ₅ C, 63.79% H, 5.35% N, 10.63% Measured value C, 63.58% H, 5.32% N, 10.49% IR (KBr) ν 1612, 1536, 1465, 1441, 1296, 1218, 109
2, 1043, 844, 749 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP9) has the formula (Formula 1) in which R1 is a methyl group, R2 and R4 are methyl groups, R3, It was confirmed that R5 was a hydrogen atom.

Example 10 Synthesis of Spiropyran Derivative (SP10) 1.5 g (6.7 mmol) of 1,3,3, -trimethyl-2-methylene-6,7-benzoindoline (11) and 3,5-dinitrosalicyl Aldehyde (2) 1.4 g (6.7 mmol) was heated and refluxed in 30 ml of ethanol for 4 hours to carry out the reaction represented by the following reaction formula (Formula 12).

[0052]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 2.7 g of spiropyran derivative (SP10) (yield 95%). The following are the physical properties of the obtained spiropyran derivative (SP10).

Melting point 249 to 250 ° C Molecular weight measurement (EI) m / z 417 (M ⁺ ), molecular weight 417.36 Elemental analysis value Calculated as C ₂₃ H ₁₉ N ₃ O ₅ C, 66.18% H, 4.59% N, 10.07% Measured value C, 66.08% H, 4.53% N, 9.96% IR (KBr) ν 1610, 1526, 1458, 1438, 1308, 1211, 109
2, 1012, 821, 738 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP10) is a compound represented by the above formula (Formula 1) in which R1 is a methyl group, R2 and R3 are hydrogen atoms, R4, It was confirmed that R5 was a benzo group.

Example 11 Synthesis of spiropyran derivative (SP11) 2.6 g (10.4 mmol) of 1,3,3,3-trimethyl-5-nitro-7-methoxy-2-methyleneindoline (12) and 3,5- 2.2 g (10.4 mmol) of dinitrosalicylaldehyde (2) was heated and refluxed in 55 ml of ethanol for 3 hours to carry out the reaction represented by the following reaction formula (Formula 13).

[0056]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 4.0 g of spiropyran derivative (SP11) (yield 88%). The following are the physical properties of the obtained spiropyran derivative (SP11).

Melting point 219 to 220 ° C. Molecular weight measurement (EI) m / z 442 (M ⁺ ), molecular weight 442.30 Elemental analysis value Calculated as C ₂₀ H ₁₈ N ₄ O ₈ C, 54.31% H, 4.10% N, 12.67% Measured value C, 54.22% H, 4.08% N, 12.55% IR (KBr) ν 1616, 1525, 1460, 1436, 1298, 1215, 108
2, 1054, 829, 742 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP11) is a compound of the above formula (Formula 1) in which R 1 is a methyl group, R 2 and R 4 are hydrogen atoms, and R 3 is It was confirmed that the nitro group and R5 were methoxy groups.

Example 12 Synthesis of Spiropyran Derivative (SP12) 2.0 g (8.0 mmol) of 1,3,3,3-trimethyl-4-nitro-7-methoxy-2-methyleneindoline (13) and 3,5- 1.7 g (8.0 mmol) of dinitrosalicylaldehyde (2) was heated and refluxed in 35 ml of ethanol for 3 hours to carry out the reaction represented by the following reaction formula (Formula 14).

[0060]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 3.1 g of spiropyran derivative (SP12) (yield 90%). The following are the physical properties of the obtained spiropyran derivative (SP12).

Melting point 238 to 239 ° C Molecular weight measurement (EI) m / z 442 (M ⁺ ), molecular weight 442.30 Elemental analysis value Calculated as C ₂₀ H ₁₈ N ₄ O ₈ C, 54.31% H, 4.10% N, 12.67% Measured value C, 54.08% H, 3.99% N, 12.60% IR (KBr) ν 1614, 1544, 1464, 1411, 1295, 1217, 109
7, 1044, 830, 737 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP11) is a compound of the above formula (Formula 1) in which R1 is a methyl group, R2 is a nitro group, R3 and R4 are It was confirmed that the hydrogen atom and R5 were methoxy groups.

(Example 13) Synthesis of spiropyran derivative (SP13) 1,3,3, -trimethyl-5-bromo-6,7-benzo-2-methyleneindoline (14) 2.0 g (6.6 mmol) and 3, 1.4 g (6.6 mmol) of 5-dinitrosalicylaldehyde (2) was heated and refluxed in 55 ml of ethanol for 3 hours to carry out a reaction represented by the following reaction formula (Formula 15).

[0064]

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The reaction mixture was cooled, filtered, and recrystallized from ethanol three times to obtain 3.0 g of spiropyran derivative (SP13) (yield 93%). The following are the physical properties of the obtained spiropyran derivative (SP13).

Melting point 269-270 ° C. Molecular weight measurement (EI) m / z 495 (M ⁺ ), molecular weight 496.25 Elemental analysis value Calculated as C ₂₃ H ₁₈ BrN ₃ O ₅ C, 55.66% H, 3.66% N, 8.47% Measured value C, 55.49% H, 3.60% N, 8.37% IR (KBr) ν 1612, 1528, 1460, 1439, 1311, 1215, 109
3, 1018, 866, 748 cm ⁻¹ Elemental analysis and IR (KBr) analysis show that the obtained spiropyran derivative (SP9) is the same as in the above formula (Formula 1), wherein R1 is a methyl group, R2 is a hydrogen atom, and R3 is a bromo group. , R4 and R5 are benzo groups.

Absorption maximum wavelengths (λmax) in various solutions of the spiropyran derivatives SP1 to SP13 of Examples 1 to 13 and the known spiropyran represented by the following formula (Formula 16) were measured. The results are shown in Table 1.

[0068]

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[0069]

[Table 1]

From Table 1, it was confirmed that the spiropyran derivatives (SP1 to SP13) obtained in Examples 1 to 13 exhibited various absorption maximum wavelengths different from known spiropyrans.

(Embodiment 14) FIG. 1 is a sectional view showing the structure of a reversible recording medium according to an embodiment of the present invention, in which a sheet-shaped support (thickness: 75 μm) 1 made of polyethylene terephthalate, The spiropyran derivative (SP1 to SP13) obtained in Examples 1 to 13 was dispersed in butyral resin to a concentration of 5 wt% to form a recording layer (film thickness: 2 μm) 2. On this recording layer 2, polyvinyl butyral (BX-1; product name of Sekisui Chemical Co., Ltd.) in which Siasorb UV-5411 (manufactured by Nippon Cyanamid Co., Ltd.), which is an ultraviolet absorber, is dispersed is formed into a film and isocyanated. A protective layer (film thickness: 0.1 μm) 3 is formed.

FIG. 2 is a diagram showing a reversible recording process using the reversible recording medium for each step. To record information, heat is applied to the reversible recording medium 4 by the thermal recording means 5 in accordance with an image signal, and the spiropyran derivative in the recording layer 2 of the reversible recording medium 4 undergoes a structural change to color from a colorless state. And the information is recorded (Fig. 2 (a),
(b)). To erase the recorded information, the visible light irradiating means irradiates the recording layer 2 of the reversible recording medium 4 with visible light,
Inverse isomerization of the spiropyran derivative therein causes reversible conversion from the colored state to the colorless state, and the recording is erased (Fig. 2
(c), (d)).

In Table 2 below, a commercially available thermal head is used as the thermal recording means 5, and a visible light lamp (Matsushita Electric Works, λmax = 615 nm, 40 W) is used as the visible light irradiating means to repeatedly record and erase information. This is the result. In the table,
(OD) is the optical density of the recording layer
Is shown. The record retention (property) is determined by the change in the optical density of the reversible recording medium 4 after being left in the dark, and the repetitive characteristic is that the recording by the recording unit 5 and the disappearance of the record by the visible light irradiation unit are alternately performed. It was determined by the results of the above.

[0074]

[Table 2]

As can be seen from Table 2, the reversible recording media using the spiropyran derivatives (SP1 to SP13) are all
The recording medium was a reversible recording medium with clear recording and excellent record retention and repeatability.

In Examples 1 to 13 described above, 2-methyleneindoline in which a methyl group is bonded to the nitrogen of the 5-membered ring containing nitrogen was used, but in the present invention, the nitrogen of the 5-membered ring containing nitrogen has a carbon number of A spiropyran derivative can also be synthesized by using 2-methyleneindoline in which alkyl groups up to 2 to 11 are bonded, and in this case, the spiropyran derivative also develops a color as in the spiropyran derivative obtained in Examples 1 to 13 above. The reverse photochromic compound has an excellent contrast between the time and the time of erasing, and has excellent reversibility of reversible color development and erasing and light resistance.

[0077]

【The invention's effect】
. As described above, according to the present invention, there is provided a novel reverse photochromic compound having excellent contrast between color development and color erasure, and also excellent reversibility of reversible color development / decoloration and light resistance. Further, by using this reverse photochromic compound, it is possible to construct a reversible recording medium having excellent record retention and repetitive properties.
Therefore, the reverse photochromic compound of the present invention is used for copying materials, facsimiles, optical filters, display materials, photometers, ornamental materials, toys, prepaid cards, commuter passes,
It is expected to be used in various fields such as coupons and rewritable paper.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of a reversible recording medium according to an embodiment of the present invention.

FIG. 2 is a diagram showing a reversible recording process using the reversible recording medium shown in FIG. 1 for each step.

[Explanation of symbols]

 1 Support 2 Recording Layer 3 Protective Layer 4 Reversible Recording Medium 5 Thermal Recording Means 6 Visible Light Irradiation Means

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Claims (18)

[Claims] 1. A reverse photochromic compound comprising a spiropyran derivative represented by the following general formula (Formula 1). Embedded image (However, R1 is an alkyl group having 1 to 11 carbon atoms,
It is either an aryl group having 1 to 20 carbon atoms, a methacryloxy group having a methylene chain having 1 to 6 carbon atoms, or a methacrylamide group having a methylene chain having 1 to 6 carbon atoms. R2, R3, R4 and R5 are a hydrogen atom, or an alkyl group, a hydroxy group, an amino group, an alkylamino group, a nitro group, a halogen group, an alkoxy group, a cyano group, a carbonyl group, a carboxyl group, an alkoxycarbonyl group, and One of a benzo group, R2,
At least one of R3, R4 and R5 is not a hydrogen atom but one of the aforementioned substituents. ) 2. R1 in the formula (Formula 1) is a methyl group, R2,
R4 and R5 are hydrogen atoms and R3 is a methoxy group.
The reverse photochromic compound described. 3. The reverse photochromic compound according to claim 1, wherein R 1 and R 3 in the formula (Formula 1) are methyl groups, and R 2, R 4 and R 5 are hydrogen atoms. 4. R1 of the formula (Formula 1) is a methyl group, R2,
The reverse photochromic compound according to claim 1, wherein R4 and R5 are hydrogen atoms and R3 is a bromo group. 5. R1 of the formula (Formula 1) is a methyl group, R2,
R4 and R5 are hydrogen atoms and R3 is a fluoro group.
The reverse photochromic compound described. 6. R1 in the formula (Formula 1) is a methyl group, R2,
The reverse photochromic compound according to claim 1, wherein R4 is a hydrogen atom and R3 and R5 are bromo groups. 7. R1 in the formula (Formula 1) is a methyl group, R2,
R4 is a hydrogen atom, and R3 and R5 are fluoro groups.
The reverse photochromic compound described. 8. R1 in the formula (Formula 1) is a methyl group, R2,
The reverse photochromic compound according to claim 1, wherein R4 is a hydrogen atom, and R3 and R5 are methyl groups. 9. R1 in the formula (Formula 1) is a methyl group, R2,
The reverse photochromic compound according to claim 1, wherein R4 is a chloro group, and R3 and R5 are hydrogen atoms. 10. R 1 of the formula (Formula 1) is a methyl group, R 1
2. R2 and R4 are methyl groups, and R3 and R5 are hydrogen atoms.
The reverse photochromic compound described. 11. R 1 of the formula (Formula 1) is a methyl group, R 1
2. A hydrogen atom as R3 and a benzo group as R4 and R5.
The reverse photochromic compound described. 12. R 1 in the formula (Formula 1) is a methyl group, R 1
2. The reverse photochromic compound according to claim 1, wherein R4 is a hydrogen atom, R3 is a nitro group, and R5 is a methoxy group. 13. R1 in the formula (Formula 1) is a methyl group, R2
The reverse photochromic compound according to claim 1, wherein is a nitro group, R 3 and R 4 are hydrogen atoms, and R 5 is a methoxy group. 14. R1 in the formula (Formula 1) is a methyl group, and R2 is
The reverse photochromic compound according to claim 1, wherein is a hydrogen atom, R 3 is a bromo group, and R 4 and R 5 are benzo groups. 15. A reversible recording medium having a recording layer formed by introducing the inverse photochromic compound according to claim 1 into a polymer side chain or dispersing the polymer in a polymer on a support. . 16. The reversible recording medium according to claim 15, wherein the recording layer is covered with a protective layer made of a heat-resistant transparent resin. 17. The reversible recording medium according to claim 16, wherein an ultraviolet absorber is dispersed in the protective layer. 18. The reversible recording medium according to any one of claims 15 to 17, wherein information is recorded on a recording layer by a thermal recording means, and the recorded information is recorded by irradiating the recording layer with visible light. A reversible recording method that erases reversibly.