JPS62299386A - Optical recording medium - Google Patents

Abstract

PURPOSE:To contrive stabilization of a developed color image both thermally and to visible rays, by heat-treating a photosensitive layer comprising a specified indolinospirobenzothiopyran compound, a high molecular weight substance and a metal naphthenate as main constituent after developing a color by irradiating the layer with UV rays. CONSTITUTION:A recording layer is constituted of a photosensitive layer formed of a photosensitive composition comprising an indolinospirobenzothiopyran compound of the formula, wherein each of R1-R3 is H, a halogen, 1-5C alkoxymethyl, hydroxymethyl or alkylaminomethyl, a high molecular weight substance and a metal naphthenate as main constituents. The photosensitive layer is irradiated with UV rays to develop a color, and thereafter it is heat-treated. The high molecular weight substance may be any one which is well compatible with the compound of the formula and has an excellent film-forming capability, and may be polymethyl methacrylate, polystyrene, a phenolic resin, a phenoxy resin or the like, among which a chlorine- containing high molecular weight substance and a phenolic resin are particularly preferable. The amount of the metal naphthenate is preferably 10-50pts.wt. per 100pts. wt. of the high molecular weight substance, and the amount of the compound of the formula is 20-120pts.wt. per 100pts.wt. of the high molecular weight substance.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to optical recording media.

[Summary of the invention]

The present invention provides an optical recording medium in which a photosensitive layer made of a photosensitive composition containing a specific indolinospilobenzothiopyran compound, a polymer substance, and a naphthenic acid metal salt as main components is irradiated with ultraviolet rays to develop a colored state. After that, it is heat-treated, making the colored image stable both thermally and against visible light.

[Conventional technology]

There are substances that exhibit photochromism that respond to ultraviolet light and form colored images. Among the organic substances that exhibit photochromism, spiropyran compounds are the most widely studied.When spiropyran compounds are used as actual photosensitive materials, they are generally dispersed and dissolved in a polymeric substance, that is, a binder resin. It is used in the form of a film or coated on a substrate.

Such conventional photosensitive materials have the property of developing color when irradiated with ultraviolet light and returning to their original colorless state when heated or irradiated with visible light. Because photochromic light-sensitive materials using spiropyran compounds exhibit such interesting properties, attempts have been made to apply them to various recording and storage materials, copying materials, display materials, and the like.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional photosensitive materials are thermally unstable in their photocolored state, gradually fading even at room temperature, and are unsuitable for long-term storage. However, the colored state is lost, and therefore, for example, for long-term storage of colored images, it is necessary to block visible light. Furthermore, when an optical recording medium using a conventional photosensitive material is used for enlarging and projecting a colored image, the image fades in a short time due to the light from the light source and disappears. There was a problem with this. For this reason, conventional optical recording media using spiropyran compounds have limitations in terms of their application.

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present invention have conducted intensive research and found that the present inventors have developed a new optical recording medium that has high thermal stability that cannot be obtained with conventional optical recording media and that is resistant to visible light. In contrast, we have developed an optical recording medium that forms stable colored images. That is, the present invention is based on the general formula (1) (where RI+, R1 and R1 each mean a hydrogen atom, a halogen atom, an alkoxymethyl group having 1 to 5 carbon atoms, a hydroxymethyl group, or an alkylaminomethyl group) The recording layer of an optical recording medium is constituted by a photosensitive layer made of a photosensitive composition mainly composed of an indolinospilobenzothiopyran compound shown by, a polymer substance, and a naphthenic acid metal salt, and this photosensitive layer absorbs ultraviolet light. The present invention provides an optical recording medium that is heat-treated after being irradiated to develop a color.

The polymeric substance may be any material as long as it has good compatibility with the compound of general formula (1) and excellent film-forming ability; examples thereof include polymethyl methacrylate,
Polystyrene, polyvinyl acetate, polyvinyl butyral, cellulose acetate, polyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinyl acetate copolymer, polypropylene, polyethylene, polyacrylonitrile, urethane resin, epoxy resin , polyester, phenolic resin, phenoxy resin, etc. Among these, chlorine-containing polymeric substances and phenolic resins are particularly preferably used.

The naphthenic acid metal salts include Zn SPb, Mn, and C.
Metal salts such as 0% Ni5Cu can be used.

The amount of the naphthenic acid metal salt is preferably 10 to 50 parts by weight based on 100 parts by weight of the polymeric substance.If it is less than 10 parts by weight, the stabilizing effect on the colored image will be small, and if it exceeds 50 parts by weight, the stabilizing effect will be small. will not increase further.

The temperature and time for the heat treatment vary depending on the photosensitive composition, but conditions can be used at 80° C. to 120° C. for several tens of minutes to several hours.

In the photosensitive composition, the content of the compound represented by general formula (1) is 20 to 20 parts by weight per 100 parts by weight of the polymeric substance.
It can be used in a range of 120 parts by weight.

In addition to the compound of general formula (1) and the polymeric substance, the photosensitive composition also contains phenols such as bisphenol A, hindered amines, hindered phenols, antioxidants such as nickel complexes, and light stabilizers. , a thermal or photocuring agent of a polymeric substance, and the like.

The photosensitive composition is dissolved in a polymeric material to form a film or formed into a photosensitive layer on a substrate by techniques known to those skilled in the art.

The substrate material includes polyacrylate, polyethylene terephthalate, cellulose acetate, polycarbonate, ordinary paper, baryta paper, glass, metal, and the like.

In the optical recording medium of the present invention, ^j! is provided on the top or bottom surface of the photosensitive layer. A reflective layer such as +Cr+Ag+Au may be provided. Further, a protective film may be provided on the upper surface of the photosensitive layer directly or via a reflective layer.

Furthermore, if a substance that blocks ultraviolet rays is used as the substrate and a reflective layer is provided on the photosensitive layer, the uncolored areas of the photosensitive layer will no longer develop color even when irradiated with ultraviolet rays, so that the colored image will not be destroyed. This is preferable in terms of long-term preservation of high contrast between colored and non-colored areas of the photosensitive layer.

The structure of the optical recording medium of the present invention can be, for example, a laminated structure shown in FIGS. 2 to 4.

In FIG. 2, a photosensitive layer 2 is provided on a substrate 1. A protective film 4 may be further provided on the photosensitive layer N2.

In FIG. 3, a reflective layer 3 is provided on a substrate 1, and a photosensitive layer 2 is provided on the reflective layer 3. Photosensitive layer 2
A protective film 4 may be further provided thereon, and the stacking order of the reflective layer 3 and the photosensitive layer 2 may be reversed.

In FIG. 4, a photosensitive layer 2 is provided on a substrate 1, a reflective layer 3 is provided on the photosensitive layer 2, and a reflective layer 3 is provided on the photosensitive layer 2.
A protective film 4 is further provided thereon.

〔Example〕

Next, the present invention will be explained in detail by way of examples.

1-4 and Comparative Example 1 In this example, a spiropyran compound represented by formula (n) was used as the indolinospilobenzothiopyran compound, and a solution was prepared with the following composition.

Spiropyran compound 50 parts by weight Phenol resin (PSK-2320, manufactured by Gunei Chemical) 100 parts by weight Naphthenic acid metal salt 30 parts by weight Solvent (tetrahydrofuran: cyclohexanone = 1:1)
600! After filtering this solution with a membrane filter (filter pore diameter: 0.45 μm), 2.
Coat on a glass substrate for 15 seconds at 00 rpm to obtain a film thickness of approximately 1.
A photosensitive layer with a thickness of μm was formed and further dried at 80"C for 2 hours to obtain a sample for an optical recording medium. As naphthenic acid metal salts, zinc naphthenate, lead naphthenate, manganese naphthenate, and cobalt naphthenate were used. Samples for optical recording media were prepared using the following methods.In addition, as a comparative example, samples for optical recording media were prepared in the same manner as above except that the naphthenic acid metal salt was not used.

Next, a filter (U
V-D33S+R-25S, manufactured by Toshiba Glass) through 5
The material was irradiated with ultraviolet light for about 5 minutes using a 00 W ultra-high pressure mercury lamp to develop color, and then heat-treated at 90° C. for 1 hour to obtain an optical recording medium (see FIG. 2).

The absorption spectra and absorbance at a wavelength of 660 nm of these optical recording medium samples before irradiation with ultraviolet light, after irradiation with ultraviolet light and before heat treatment, and after heat treatment are shown in FIG. 1 and Table 1, respectively.

Next, these optical recording media were irradiated with visible light with a wavelength longer than 500 nm at an intensity of 150 mW/a+l using a Y-50 filter (manufactured by Toshiba Glass) to examine their photostability. The results are shown in Table 1.

(Continued on next page) Here, photostability was expressed as the time required for the absorbance to decrease by 0.1.

From Table 1, it can be seen that when metal naphthenate is not used, the exposure time required for a 0.1 change in absorbance is approximately 10 minutes, while when metal naphthenate is used, the exposure time is approximately 60 minutes. It can be seen that the photostability is significantly improved.

Each optical recording medium of this example was left at 50°C for one month.
The decrease in absorbance was suppressed within 10% in all cases. Further, in this example, nickel naphthenate or copper naphthenate was also effective as the naphthenic acid metal salt.

Methods 5 to 7 Furnace side 2 As an indolinospilobenzothiopyran compound, the formula (I
II) A sample was prepared using the compound shown in Example 1 and Comparative Example 1 with the same composition and operation, and in the same manner as Example 1, this sample was irradiated with ultraviolet light through a mask for 5 minutes. death,
Further, heat treatment was performed at 95° C. for 1 hour to obtain an optical recording medium having a colored area (exposed area) and an uncolored area (unexposed area).

Next, in order to investigate the stability of the colored image of this optical recording medium,
AJ was deposited on this optical recording medium, and then an ultraviolet curing resin HO5!23U (manufactured by Quant Kasei Co., Ltd.) was applied on the Af vapor deposited film, and ultraviolet light was further irradiated to create optical recording media as a protective film. (See Figure 4). Next, changes in reflectance at a wavelength of 660 nm when these optical recording media were stored at 60° C. for one month were investigated. The results are shown in Table 2.

(Continued on the next page) From Table 2, it can be seen that the optical recording medium of this example shows almost no change in reflectance in both colored and non-colored areas even when left at 60°C for one month, and is thermally stable. I understand that there is something.

A solution having the following composition was prepared using the spiropyran of formula (III) used in Example 5 as the indolinospirobenzothiobilane compound and cobalt naphthenate as the naphthenic acid metal salt. Apply this solution to a yellow acrylic plate in the same manner as step 1 and dry it to a thickness of about 1.5 μm.
A sample was obtained having a photosensitive layer with a thickness of .

Spiropyran compound 100 parts by weight Cobalt naphthenate 40 parts by weight Phenol resin (
(PSK-2320, manufactured by Kozo Kagaku) 100 parts by weight cyclohexanone 600 parts by weight Next, this photosensitive layer was irradiated with ultraviolet light through a mask having an image to transfer the image onto the photosensitive layer.

After heat-treating this sample at 95° C. for 40 minutes, an A1 reflective layer was deposited on the photosensitive layer to which the image had been transferred. Next, Example 2
An optical recording medium was obtained by depositing a protective film on the A1 reflective layer using the method described above (see FIG. 4).

The reflectance of the optical recording medium obtained in this way was measured at wavelength 632.
When measured using a He-Ne laser beam with a beam diameter of 8 nm and a beam diameter of 1 μm, the reflectance of the colored portion and the non-colored portion was 4% and 73%, respectively, indicating that high contrast was obtained.

In the optical recording medium of this example, since the photosensitive layer as a recording layer is sandwiched between the ultraviolet-blocking acrylic substrate and the reflective layer, even if the optical recording medium is irradiated with ultraviolet light, the photosensitive layer The uncolored portions do not develop color, so the recorded pattern is not destroyed.

In addition, the optical recording medium of this example is stable against heat and light, especially visible light, like the optical recording medium of each of the above examples, and is stable against visible light with a wavelength of 420 nm or more (light intensity: 200 mW).
/cflI) for 20 hours without any substantial decrease in contrast. On the other hand, for comparison, in an optical recording medium obtained in the same manner without using naphthenic acid metal salt, the reflectance of the colored part changed from 4% to 18% after about 20 minutes of visible light irradiation, and the contrast decreased. It decreased significantly. In the optical recording medium of this example, the reflectance of the colored portion only changed from 4% to 10% even after 20 hours of visible light irradiation.

〔Effect of the invention〕

In the optical recording medium of the present invention, a photosensitive layer consisting of a photosensitive composition mainly composed of a certain indolinospilobenzothiopyran compound, a polymer substance, and a naphthenic acid metal salt is irradiated with ultraviolet rays to develop a colored state. After that, it is heat treated.

Therefore, it is possible to provide a photosensitive composition in which thermal instability and visible light instability of colored images, which are disadvantages of conventional spiropyran-based photosensitive materials, are improved, and the optical recording medium of the present invention can be stored for a long period of time. It can be used in recording storage materials and copying materials that require stability, and can also be used in the field of displays that magnify and project images by irradiating visible light.

Furthermore, in the optical recording medium of the present invention, since the photosensitive composition does not have particle properties and the spiropyran molecule itself changes, it is possible to record minute dots with ultraviolet rays at high resolution. In addition, since the colored portion of the optical recording medium of the present invention exhibits strong absorption in the wavelength range of 600 to 700 nm,
The colored pattern can be read out using a laser or light emitting diode that oscillates in this wavelength range, and therefore can be used for optical cards and the like.

[Brief explanation of drawings]

FIG. 1 is a graph showing the absorption spectrum of the optical recording medium in Example 1, and FIGS. 2 to 4 are diagrams showing the structure of the optical recording medium of the present invention. In addition, in the reference numerals used in the drawings, 1.--.--.--1 substrate 2-..-.--1--.. Photosensitive layer.

Claims (1)

[Claims] General formula ▲ Numerical formula, chemical formula, table, etc.
A photosensitive layer consisting of a photosensitive composition mainly composed of an indolinospilobenzothiopyran compound represented by a hydroxymethyl group or an alkylaminomethyl group, a polymeric substance, and a naphthenic acid metal salt can be used to record an optical recording medium. 1. An optical recording medium comprising a recording layer, the photosensitive layer being irradiated with ultraviolet rays to become colored and then heat-treated.