JPS6113496B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to photochromic photosensitive compositions.

There are many photochromic compounds, both organic and inorganic, that are colorless in the dark at room temperature, but develop color when exposed to ultraviolet rays, and return to colorless when left in the dark or heated. Among these photochromic compounds, spiropyran compounds are known as particularly effective ones.

The spiropyran compound of the present invention is normally in a colored state, contrary to the normal photochromism described above, and is decolored by being irradiated with light, and this decolored state is thermally restored to the original colored state. This shows the "reverse photochromism" of going back.

To obtain images using ordinary photochromic compounds, it is necessary to use ultraviolet light, but as the cycle of coloring and decoloring with ultraviolet light is repeated, the color gradually stops forming. This is thought to be because the photochromic compound is decomposed by ultraviolet rays. In the case of a spiropyran compound, the number of cycles is about 30 at most, although it varies slightly depending on the type and usage conditions. On the other hand, in the case of inverse photochromic compounds, there is no need to use ultraviolet rays, visible light can be used to obtain images, and the cycle life of decoloring and coloring can be dramatically extended compared to photochromic compounds. It is.

As such inverse photochromic compounds,
In spiropyrans, as shown in the formula below,
8′-carboxylic acid derivatives are known (Japanese Unexamined Patent Application Publication No. 1989-1989)
-89179, 48-89180).

However, since this spiropyran compound is water-soluble, photochromic photosensitive compositions containing this spiropyran compound as an active ingredient have the disadvantage of being sensitive to water and moisture.

In addition, other known spiropyran compounds are water-insoluble compounds, but their compatibility and solubility in organic solvents and polymeric substances as binders are low, resulting in insufficient performance in photochromic photosensitive compositions. . That is, the spiropyran concentration in the photosensitive layer was low due to low compatibility with the medium, resulting in low color image density and insufficient contrast. Another drawback is that increasing the thickness of the photosensitive layer in order to increase the contrast lowers the resolution.

The present invention solves these conventional drawbacks and provides a photochromic material that has high contrast, high resolution, high photosensitivity, and has a long decolorizing-coloring cycle life. Furthermore, the composition of the present invention is characterized in that it is relatively stable when decolored by light stimulation, and as long as it is stored in a dark place at room temperature, it can retain a clear image for about half a month.

The present invention is a photochromic photosensitive composition characterized in that a compound represented by the following general formula is dispersed in a polymeric substance.

(Here, R ₁ is an alkyl group having 12 to 30 carbon atoms; R ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 2 to 5 carbon atoms.
Indicates 6 alkoxycarbonyl groups or halogen atoms. That is, in the present invention, by substituting the N-position of 6',8'-dinitroindolinobenzopyrylylspirane with an alkyl group _R1 having a large number of carbon atoms, the present invention solves the problem of the conventional drawback of low resistance to solvents and media. The compatibility and low solubility were successfully improved. It is essential that this alkyl group has 12 to 30 carbon atoms. If it is less than 12, the compatibility deteriorates, and if it exceeds 30, the melting point decreases and crystallinity deteriorates.

The structure of the above general formula is considered to be the structural formula of the spiropyran compound when it is decolored, and the stable structure when it is colored can be written as follows.

The spiropyran compound represented by the above general formula is
By dehydration condensation reaction of 1-long-chain alkyl-3,3-dimethyl-2-methyleneindoline derivative and 3,5-dinitrosartylaldehyde, or by 1-long-chain alkyl-2,3,3-trimethylindolenium It can be easily synthesized by reacting -P-toluenesulfonate or its P-chlorobenzenesulfonate with 3,5-dinitrosartylaldehyde in the presence of an amine.

The above compounds include alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone, ethers such as ethyl ether, dioxane, and tetrahydrofuran, and ethyl acetate and n-butyl acetate. It dissolves in esters, various solvents such as benzene, toluene, xylene, acetonitrile, dimethylformamide, dimethyl sulfoxide, chloroform, and mixed solvents thereof.

In order to use the above-mentioned compound as a photochromic photosensitive composition, the above-mentioned compound may be dissolved together with a polymeric substance in the above-mentioned solvent and formed into a film, or applied and dried on a support. The above compounds can also be kneaded and dissolved to form a film for use.

In this case, in the photochromic photosensitive composition of the present invention, in order to obtain sufficiently high sensitivity and high contrast with a photosensitive layer thickness of several microns to 1 micron or less, the spiropyran concentration in the preparation must be adjusted to a high molecular weight as a binder. On the other hand, it is better to use as much spiropyran compound as possible as long as it dissolves, but if the amount of spiropyran compound is too large, the binder will be relatively small and the film forming properties will be poor, so it is used in an amount in the range of 20 to 60%. . Further, the amount of the spiropyran compound added is 2 to 20 PHR (PHR indicates parts by weight per 100 parts by weight of the polymeric substance) relative to the polymeric substance. That is, if it is less than 2 PHR, the contrast will deteriorate, and if it exceeds 20 PHR, it will become difficult to dissolve in the solvent and the film forming property will deteriorate.

The polymeric substances used in the present invention may be those having good compatibility with spiropyran and excellent film-forming ability, such as polymethyl methacrylate, polystyrene, polyvinyl acetate, polyvinyl butyral, cellulose acetate, Polyvinyl chloride, polyvinylidene chloride, polypropylene,
Examples include polyethylene, polyacrylonitrile, urethane resin, epoxy resin, and polyester.

Supports used in the present invention include ordinary paper, baryta paper, cellulose acetate, polyethylene terephthalate, polycarbonate, polyimide, glass, metal, and the like.

Under normal conditions, the composition of the present invention has stable absorption in the visible region of 500 to 600 mm and is strongly colored magenta. It has the characteristic that when irradiated with visible light or ultraviolet light, the color immediately disappears, and when it is heated in this state to 60° C. or higher, it returns to its original colored state, and these changes repeat. The composition of the present invention having these characteristics can be used in a wide range of fields, including various recording and storage materials in place of silver salt photosensitive materials, copying materials, printing photoreceptors, CRT recording materials, It can be used as a variety of recording materials such as a light-sensitive material for lasers, a light-sensitive material for holography, and a light-sensitive material for phototypesetting. It can also be used as a material for optical filters, display materials, masking materials, light meters, decorations, etc.

The method for forming an image using the photosensitive composition of the present invention is to irradiate the photosensitive layer of the photosensitive composition of the present invention with visible light or ultraviolet rays to decolorize the entire surface, and then heat it in an imagewise manner. There are ways to obtain colored images. Another method is to obtain an image by irradiating the photosensitive layer with an optical image of visible light or ultraviolet rays to decolorize the exposed areas. Further, a method of forming an image by scanning visible or ultraviolet laser light on the photosensitive layer of the composition of the present invention and decolorizing the exposed areas can also be used.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 2,3,3-trimethylindolenine and 1-octadecyl iodide were refluxed in a sealed tube using chloroform as a solvent for 24 hours to obtain 1-octadecyl-iodide.
2,3,3-trimethylindolenium iodide was synthesized. This was treated with sodium hydroxide to obtain 1-octadecyl-3,3-dimethyl-2-methyleneindoline. Thus synthesized 1-
4 g of octadecyl-3,3-dimethyl-2-methyleneindoline and 2 g of 3,5-dinitrosartylaldehyde were dissolved in 100 ml of ethyl alcohol and refluxed for 3 hours. After the reaction, the ethyl alcohol was distilled off and upon cooling, brown crystals were precipitated.
Take this, wash it with ethyl alcohol, dry it, and recrystallize it from ethyl alcohol to give 4.5 g.
6′,8′-dinitro-1-octadecyl-3,3-
Crystals of dimethylspiro [indoline-2,2'-benzopyran] were obtained.

Using the spiropyran compound thus obtained,
A photosensitive film having the following composition was prepared using polystyrene as a binder.

Spiropyran 0.05g Polystyrene 0.95g Toluene 10ml First, prepare the above composition (toluene solution),
This was applied onto a polyester film and dried to produce a uniform photosensitive film with a photosensitive layer thickness of 10 microns. This film had absorption at a visible wavelength of 550 mm with an optical density of 2.6, and was strongly colored magenta. This photosensitive film was irradiated with visible light around 530 nm for 1 minute using an ultra-high pressure mercury lamp (500 W, manufactured by Ushio Inc.) through a filter (G-53S, manufactured by Toshiba Glass). The color immediately disappeared to an optical density of 0.13. When heated above 60°C, the original optical density was completely restored. FIG. 1 shows the absorption spectra of this film before exposure (1 in the figure) and after exposure (2 in the figure).

For comparison, 6′,8′-dinitro-1,
3,3-trimethylspiro[indoline-2,
An attempt was made to produce a photosensitive film using 2'-benzopyran] in exactly the same manner as above, but this spiropyran compound did not dissolve at all in toluene and no colored film could be obtained.

Example 2 6',8'-dinitro-1-octadecyl-3,3
-Dimethylspiro[indoline-2,2'-benzopyran] was prepared into a solution with the following composition using polyvinylidene chloride as a binder.

Spiropyran 0.05g Polyvinylidene chloride 0.95g Tetrahydrofuran-cyclohexanone
10 ml (1:1) mixed solvent This solution was applied onto a polyester film and dried to prepare a photosensitive film with a thickness of 5 microns. This film had visible absorption at a wavelength of 540 nm with an optical density of 1.6, and was colored deep red. In addition, a xenon lamp (manufactured by Ushio Inc.)
When irradiated with light using a heat absorbing filter (500W), the color completely disappeared in about 15 seconds. FIG. 2 shows the absorption spectra of this film before exposure (1 in the figure) and after exposure (2 in the figure).

A mask having an image of a metal vapor deposited film on a quartz glass substrate was closely attached to this photosensitive film, and when light was irradiated with a xenon lamp, a positive image was obtained in which this mask pattern was accurately copied onto the film. If you store this image in a dark place at 22℃,
I was able to retain this image in a clear shape, about half a moon.

Example 3 6',8'-dinitro-1-dodecyl-3,3-dimethylspiro[indoline-2,2'-benzopyran] synthesized in the same manner as in Example 1 (melting point 142
~143°C), a solution with the following composition was prepared.

Spiropyran 0.05g Vinyl chloride-vinyl acetate copolymer 0.95g (VYHH manufactured by UCC) Methyl ethyl ketone-cyclohexane 10g (7:3) mixed solvent After coating this solution on a polyester film and drying it, the thickness of the photosensitive layer was 7.5 microns. A photosensitive film was obtained. This photosensitive film has wavelengths in the visible range.
It has absorption at 550 nm with an optical density of 2.78, and when irradiated with light using a 500 W xenon lamp (manufactured by Ushio Inc.) with a heat absorption filter interposed, the color disappeared to an optical density of 0.1 in about 30 seconds. When this was heated above 80°C, it completely recovered to its original optical density.

Example 4 6',8'-dinitro-1-hexadecyl-3,3-dimethylspiro[indoline-2,2'-benzopyran] synthesized in the same manner as in Example 1 (melting point
A solution having the following composition was prepared using 144-145°C.

Spiropyran 0.05g Vinyl chloride-vinyl acetate-vinyl alcohol
0.95 g copolymer (VAGH manufactured by UCC) 10 g (8:2) mixed solvent of methyl ethyl ketone and cyclohexane This solution was applied onto a polyester film and dried to obtain a photosensitive film with a photosensitive layer thickness of 8 microns. This film had absorption at a visible wavelength of 540 nm with an optical density of 2.6, and was colored deep red.
A mask made of quartz glass with an image of a metal vapor deposited film on the surface is closely attached to the photosensitive layer of this film, and when light is irradiated from the mask side with a xenon lamp, this mask pattern is accurately copied onto the film as a positive image. was gotten. This image could be kept clear for about two weeks at room temperature in a dark place.

[Brief explanation of the drawing]

FIGS. 1 and 2 show the absorption spectra in the visible region of a photochromic material using a photosensitive composition according to an embodiment of the present invention, where 1 in the figure indicates the absorption spectrum before exposure, and 2 in the figure indicates the absorption spectrum before exposure. This is the later absorption spectrum.

Claims (1)

[Scope of Claims] 1. A photochromic photosensitive composition comprising a compound represented by the following general formula dispersed in a polymeric material at a ratio of 2 to 20 parts by weight per 100 parts by weight of the polymeric material. . (Here, R ₁ is an alkyl group having 12 to 30 carbon atoms; R ₂ is a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, or an alkyl group having 2 to 5 carbon atoms.
Indicates 6 alkoxycarbonyl groups or halogen atoms. )