JPH02275943A - Organic material for optical recording - Google Patents

Abstract

PURPOSE:To obtain the org. material for optical recording which has the excellent preservable stability of color developing species and is reversibly colored and decolored by adding arom. zinc oxycarboxylate to a spiropyran compd. CONSTITUTION:The arom. zinc oxycarboxylate is added to the spiropyran compd. The color developing chemical species of the spiropyran compd. are greatly stabilized if 50 to 10000pts.wt. arom. zinc oxycarboxylate is incorporated into 100pts.wt. spiropyran compd. While the reason for stabilizing the color developing chemical species is not elucidated, the reason is considered to lie in that the arom. zinc oxycarboxylate has the effect to stabilize the merocyanine structure which is the chemical structure of the color developing species. Further, is reversibly decolored by irradiating the color developing species thereof with visible light and is colored again by irradiating the species with YV rays. In addition, the color developing species are stable. The preservable stability of the color developing phase is improved in this way and the org. material for optical recording which is reversibly colored and decolored is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an organic material for optical recording, and more specifically, an organic material for optical recording that has excellent storage stability of the color phase and reversibly develops and fades color. Regarding materials.

A variety of organic and inorganic substances have been known to exhibit chromism, that is, substances that absorb electromagnetic energy and reversibly change its color. As the photochromic substance, especially L3,3
- Spiropyran compounds having a basic skeleton of -trimethylspiro(indoline-2,2'-benzopyran) and similar compounds thereof have been widely studied.

In order to use such a spiropyran compound as an optical recording material, for example, the spiropyran compound is dispersed in a binder made of a polymeric substance and formed into a film, or it is dissolved together with the binder in an appropriate solvent and placed on an appropriate support. It is applied, dried and used as a thin film. These spiropyran compounds are usually colorless or light-colored, but they become colored when irradiated with ultraviolet rays, and are reversibly decolored when heated or irradiated with visible light. That is, recording can be performed by irradiating such an optical recording material with ultraviolet light, and the recording can be erased by irradiating it with visible light. Therefore, in recent years, such optical recording materials have been studied for use as laser recording media such as optical video discs.

However, conventionally, optical recording materials using such spiropyran compounds generally have a problem in that the storage stability of coloring species is low, resulting in poor recording stability. That is, the colored chemical species of the spiropyran compound naturally undergoes a decoloring reaction due to thermal action, for example, even when stored at room temperature under indoor light or even when stored in the absence of light.

Therefore, various methods have been proposed to solve this problem. For example, JP-A-60-26288
Publication No. 4 proposes a method of using an antioxidant as a storage stabilizer for color-forming chemical species;
No. 39746 proposes a method using an oxime ester compound such as p-methylace1-phenone oxime acetate as a stabilizer.

Furthermore, various methods for stabilizing spiropyran compounds by trimerization or polymerization have been proposed. For example, JP-A-60
-177089 proposes storage stabilization of colored species by improving the chemical structure itself, and JP-A-60-2
No. 08390 proposes storage stabilization of colored species by trimerization. JP-A-59-227972 proposes a method of bonding a spiropyran compound as a side chain to the main chain of a polymer.

The inventors of the present invention have conducted extensive research to solve the problem of the storage stability of colored species in conventional optical recording materials using spiropyran compounds as described above. It has been discovered that the storage stability of the colored species is significantly improved by adding zinc oxycarboxylate, and furthermore, by irradiating the colored species of such an optical recording material with visible light, the color can be reversibly erased. This discovery led to the present invention.

The organic material for optical recording according to the present invention is characterized in that it contains a spiropyran compound and a zinc aromatic oxycarboxylate.

The spiropyran compound used in the present invention preferably has the formula (1) (wherein Ar' and Ar'' each represent a divalent aromatic group or a heteroaromatic group which may have a substituent. ,X
indicates O or C112R2, Y stands for 0 or S, Z
represents C11 or N, 171 represents an alkyl group having 1 to 20 carbon atoms, and R2 each independently represents an alkyl group having 1 to 5 carbon atoms. ).

In the spiropyran compound represented by the above formula (I), Ar' and Ar'' each represent a divalent aromatic group or a heteroaromatic group which may have a substituent; The aromatic group may be a monocyclic group or a polycyclic group formed by condensing two or more plural (hetero) aromatic rings, and specific examples include a phenylene group, a naphthylene group, an (iso)quinolylene group, etc. can be mentioned.

These aromatic groups or heteroaromatic groups include an alkyl group, an alkoxy group, or a thioalkoxy group having 1 to 5 carbon atoms, preferably a methyl group, a methoxy group, or a thiomethoxy group, a halogen atom such as bromine or chlorine, It may have a substituent such as a dialkylamine group such as a dimethylamino group, a sulfonic acid group, a hydroxyl group, an alkoxyalkyl group, an acyloyl group such as an acetyloxy group, or an acryloyloxy group. .

The spiropyran compound particularly preferably used in the present invention has the formula (II) (II) (where χ represents C(CI43)2 or S, Y represents O or S, and R1 has 1 to 20 carbon atoms. represents an alkyl group, R2, R4 and R5 represent hydrogen, an alkyl group having 1 to 5 carbon atoms, or an alkoxy group, R3 represents a nitro group, a hydroxyl group,
Indicates a sulfonic acid group or a halogen atom. ).

Therefore, specific examples of spiropyran compounds used in the present invention include, but are not limited to, the following.

C113 R' (p Ba n-CbH 3 groups or n-C 811□ Indicates the group.

C1(.

(R is n C,H Indicates the group.

([hmm teeth C61( : Indicates one unit.

C1hOC1, C113 (R L” n-Cb II Three methods are shown.

■ etc. can be mentioned.

Furthermore, in the present invention, a compound in which two molecules of the above-mentioned spiropyran compound are bonded can also be used.

Such spiropyran compounds include, for example, -ritual (IV) zinc carboxylate, -ritual (III) (IV) (R1 is, for example, -(Cllz) 5-2-(C1l
z)+o-1 group, etc. ) can be exemplified.

Furthermore, as described in JP-A-59-227972, for example, a polymer in which the above-mentioned spiropyran compound is bonded as a side chain to the main chain of a polymer can also be used.

Next, aromatic oxy (III) used in the present invention
) (In the formula, Ar' represents a divalent aromatic group.) The aromatic group may be a monocyclic or a condensed polycyclic aromatic group in which two or more aromatic rings are condensed. Well, also carbon number 1-20
may have an alkyl group, an alkoxy group, a halogen atom, an ester group, etc.

Therefore, examples of zinc aromatic oxycarboxylate preferably used in the present invention include zinc salicylate,
-Hydroxy-2-naphthoic acid zinc, 2-hydroxy-
Examples include zinc 1-naphthoate and zinc 3-hydroxy-2-naphthoate.

In particular, in the present invention, zinc 1-hydroxy-2-naphthoate or zinc 2-hydroxy-3-naphthoate is preferably used.

The organic material for optical recording according to the present invention preferably contains 100 parts by weight of a spiropyran compound and 50 to 100 parts by weight of an aromatic oxinocarboxylic acid zinc salt.

The organic material for optical recording according to the present invention includes the above-mentioned YotsuQ,
Contains a spiropyran compound and a zinc aromatic oxycarboxylate, and when using it, as mentioned above, these are dispersed in a binder made of a polymeric substance and formed into a film, or as necessary. It may be dissolved in an appropriate solvent using a binder, applied onto an appropriate support, and dried to form a thin film.

The binder is not particularly limited, but it is preferably one that is highly compatible with the spiropyran compound and aromatic oxycarboxylic acid used, is optically transparent, and has excellent film-forming ability. Therefore, for example, polymethyl methacrylate, methyl methacrylate copolymer, polystyrene, polyvinyl acetate, polyvinyl butyral, cellulose acetate, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinyl acetate copolymer, polypropylene, polyethylene, Examples include polyacrylonitrile, polyurethane, epoxy resin, polyethylene terecrate, and the like.

Examples of solvents include lower aliphatic alcohols such as methanol, ethanol, and propatool; lower alkyl ketones such as acetone and methyl ethyl ketone; acetate esters such as ethyl acetate, propyl acetate, and butyl acetate; and fats such as dimethylformamide. Group carboxylic acid amides, dimethyl sulfoxide, etc. are used.

Furthermore, the optical recording composition according to the present invention may contain a sensitizer.

The organic material for optical recording according to the present invention reversibly develops and erases color. That is, when the organic material for optical recording according to the present invention is irradiated with ultraviolet rays, it develops a color, and when it is irradiated with visible light of 540 nm or more, the color is erased, and when it is irradiated with ultraviolet rays again, the color is developed. do. Moreover, in such reversible color development/discoloration, the coloring species is stable in the dark, as described above.

As described above, the organic material for optical recording according to the present invention contains a spiropyran compound and a zinc aromatic oxycarboxylate, and significantly stabilizes the color-forming chemical species of the spiropyran compound.

In the organic material for optical recording according to the present invention, the reason why the aromatic oxycarboxylic acid zinc stabilizes the coloring chemical species is not yet clear, and although the present invention is not limited by any theory, This appears to be because zinc aromatic oxycarboxylate has an effect of stabilizing the merocyanine structure, which is the chemical structure of the coloring species.

Furthermore, the organic material for optical recording according to the present invention reversibly decolors by irradiating the colored species with visible light, and develops color again when it is irradiated with ultraviolet rays, and furthermore, this colored species is stable. It is.

The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 The following was used as a spiropyran compound, and it was mixed in an amount of 8 x 10-3 mol/j2, and zinc aromatic oxycarboxylate shown in Table 1 was added in an amount of 4 x 10-2 mol/I! Both were dissolved in ethanol to prepare a solution.

This solution was applied onto a glass plate at a thickness of 10 to 30 ml/nf, and then the solvent was evaporated under vacuum to form a thin film.

Next, ultraviolet rays were applied to the thin film through a UV-D36C filter (manufactured by Toshiba Glass ■) using an ultra-high pressure mercury lamp.
After being irradiated for 0 seconds to develop color, it was placed in a dark place and the change in reflection density over time was examined using a TLC scanner (manufactured by Shimadzu Corporation). The measurement wavelength was 550 nm. The results are shown in Table 1.

Table 1 (Note) S8 is zinc salicylate, l-11-2-N is 1
Showing zinc monate to hydroxy-2-naph 1.

The present invention shows that color-forming species are stably stored over very long periods of time.

Example 2 As a spiropyran compound, the following was used, and it was mixed with 8 x ], 0-3 mol/l, and the aromatic oxycarboxylic acid zinc shown in Table 2 was mixed with 4 x 10-'' mol/l! So that
Both were dissolved in ethanol to prepare a solution.

This solution was applied onto a glass plate in an amount of 10 to 30 ml/n, and then the solvent was evaporated under vacuum to form a thin film.

Next, ultraviolet rays were applied to the thin film through a uV-D36C filter (manufactured by Toshiba Glass ■) using an ultra-high pressure mercury lamp.
After being irradiated for 0 seconds to develop color, it was placed in a dark place and the change in reflection density over time was examined using a TLC scanner (manufactured by Shimadzu Corporation). The measurement wavelength was 600 nm. Second result
Shown in the table.

The present invention shows that color-forming species are stably stored over very long periods of time.

Example 3 H3 was used as a spiropyran compound, and it was mixed in an amount of 8 x 10-3 mol/12, and zinc aromatic oxycarboxylate shown in Table 3 was added in an amount of 4 x 10-2 mol/42. Both were dissolved in ethanol to prepare a solution.

This solution was applied onto a glass plate at a rate of 10 to 30 ml/ffl, and then the solvent was evaporated under vacuum to form a thin film.

Next, a UV-D 36C filter (
After irradiating ultraviolet rays with an ultra-high pressure mercury lamp for 30 seconds through a Toshiba Glass (manufactured by Toshiba Glass) to develop color, place it in a dark place.
Changes in reflection density over time were examined using a TLC scanner (manufactured by Shimadzu Corporation). The measurement wavelength was 600 nm. The results are shown in Table 3.

Table 3 (Note') 1-H-2-N represents zinc 1-hydroxy-2-naphthoate, 2-3-N represents 2-hydroxy-
Shows zinc 3-naphthoate.

Example 4 As a spiropyran compound, 8×10−3 mol/jl! Also, ■-hydroxy-2-naphthoic acid zinc was diluted with ethanol to give a concentration of 0°16 mol/β. Eight rounds of No were produced.

This solution was applied onto a glass plate in an amount of 10 to 30 ml/n, and then the solvent was evaporated under vacuum to form a thin film.

Next, ultraviolet rays were applied to the thin film through a UV-D36C filter (manufactured by Toshiba Glass ■) using an ultra-high pressure mercury lamp.
It was irradiated for 0 seconds to develop color. Next, when this colored thin film was irradiated with visible light having a wavelength of 540 nm or more for 10 minutes using an ultra-high pressure mercury lamp through a 0-54 filter, the color of the thin film was almost completely erased.

When this thin film was irradiated with ultraviolet light again, the color developed to the same density as before after 2 minutes of irradiation. Moreover, this colored species was stable in the dark.

Figure 1 does not show the color development by UV irradiation, the decolorization by visible light irradiation, the color development by re-UV irradiation, and the change in reflection density over time when this was left in a dark place.

Comparative Example 1 A test similar to Example 4 was conducted except that zinc 1-hydroxy-2-naphthoate was not used.

FIG. 1 shows the color development due to ultraviolet irradiation, the decolorization due to visible light irradiation, the color development due to UV irradiation again, and the change in reflection density over time when this was left in a dark place.

Example 5 CI+ was used as a spiropyran compound, and it was added to 8 x 10-2 mol/l, and zinc ]-hydroxy-2-naphthoate was added to 0.
Further, as shown in Table 4, 15 weight of polymethyl methacrylate, methyl methacrylate butyl methacrylate-acrylonitrile copolymer, or methyl methacrylate-butyl methacrylate-croton was added to the spiropyran compound so that the amount was 8 mol/E. A solution was prepared by dissolving both acid copolymer resins in methyl ethyl ketone.

This solution was applied onto a glass plate in an amount of 50 to 80 ml/n, and then the solvent was evaporated under vacuum to form a thin film.

Next, ultraviolet rays were applied to the thin film through a UV-D36C filter (manufactured by Toshiba Glass ■) using an ultra-high pressure mercury lamp.
It was irradiated for 0 seconds to develop color. After this color development, changes in reflection density over time were examined in a dark place.

In this way, after leaving it in the dark for 72 hours, 0-54
Wavelength 540 using an ultra-high pressure mercury lamp through a filter
Decolorization behavior was investigated by irradiating with nm light.

After 20 minutes of visible light irradiation, ultraviolet rays were irradiated again, and changes in reflection density over time were measured using a TLC scanner (
(manufactured by Shimadzu Corporation) to examine color development behavior.

The measurement wavelength was 600 nm.

The above results are shown in Table 4.

[Brief explanation of drawings]

Figure 1 shows the coloring of the organic material for optical recording according to the present invention and the organic material for optical recording as a comparative example when irradiated with ultraviolet rays, decoloring when irradiated with visible light, coloring when irradiated with ultraviolet rays again, and when left in a dark place. 3 is a graph showing changes in reflection density over time. Patent applicant Nagase Chemical Industries, Ltd.

Claims (1)

[Claims] (1) An organic material for optical recording characterized by containing a spiropyran compound and a zinc aromatic oxycarboxylate.