JPH02264246A - Photochromic material using clay as carrier matrix - Google Patents

Abstract

PURPOSE:To easily and inexpensively fix a photochromic compd. and to enhance practicability by using a composite material composed of an ionic org. material having a specific structure and clay ore. CONSTITUTION:The composite material consisting of the ionic org. material having the structure expressed by formula I and the clay ore is used. In the formula I, R denotes a dialkyl ammonium salt or nitrogenous arom. quaternary salt; X denotes CnH2n+1(n=0 to 10), OCmH2m+110), NO2 groups. The clay ore is the smectite mineral generic to silicate ores having a three-layer structure. A film and surface coated film exhibiting a photochromic effect are easily obtd. by immobilizing a spiropyrane compd. to the clay ore as the composite therewith in such a manner. The recording or erasing of images is possible by irradiating this composite film, etc., with a laser beam, visible rays, etc. The applications of the photochromic compd. are thus widened.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a functionalized photochromic phenomenon useful as a display or recording material, and consists in the use of the above-mentioned spiropyran combined with clay.

[Prior art and its problems] A huge number of organic and inorganic substances are known to exhibit the photochromic phenomenon, which is a reversible light-emitting and decolorizing process due to the action of light or heat. Only halide glass has been put into practical use. Research on the practical application of organic photochromic materials is also being actively conducted, and spiropyran is a representative example. However, spiropyran crystals do not exhibit photochromic phenomena, and the majority change color under the action of light or heat in solution or in a polymer matrix. For practical use, spiropyran compounds must be immobilized on a solid-phase support matrix, as they are likely to be used in a solid phase like other functional materials. Known methods for immobilization include 1) dispersion in a polymeric medium, 2) coating on the surface of a solid support, and 2) formation of a Langmuir-Prodgett film (hereinafter referred to as LBIIi).

As a method for dispersing a hespiropyran compound in a polymeric medium, a film casting method is usually used in which the polymeric material and the spiropyran compound are both dissolved in a solvent and then the solvent is removed. The disadvantage of this method is that a good solvent for both the polymer and the spiropyran compound must be sought, and the solvents are limited. Furthermore, unevenness is likely to occur due to the difference in solubility between the two during evaporation of the solvent. Moreover, there are many restrictive conditions, such as the polymer used must be transparent in the visible region. It has also been attempted to chemically modify polymers directly with spiropyran as pendants, but this has problems with stability as it is held at high temperatures for long periods of time during the molding process.
It has not been put into practical use.

The method for coating the surface of a solid support involves simply dispersing spiropyran in a polymer or the like and coating the composite on the solid surface, thereby solving exactly the same problem as above.

Methods for forming LB films are currently being actively researched;
Since spiropyran alone cannot form an LB film, LB
An LB film must be created by dissolving it in a compound that easily forms a film. How to fix spiropyran compounds in this way is a very important technical problem for practical use.

[Problems to be Solved by the Invention] An object of the present invention is to provide a highly practical photochromic material by fixing a photochromic compound simply and inexpensively.

The present invention relates to the application of photochromic compounds having a spiropyran skeleton to display or recording materials.
A photochromic compound having a spiropyran skeleton as shown below is incorporated between the clay layers, and its photochemical decolorization-thermal coloration repeating characteristics are improved by compounding with the clay.

[Measures to solve the problem] The present invention has the following configuration (1).

(11 Composite material of an ionic organic substance and a clay mineral having the structure of the following formula (1) (R in the formula is a dialkyl ammonium salt or a nitrogen-containing aromatic quaternary salt.

X is CnH2n+I (n=ONl0), OCm
82m++ (ffi = 1~In), represents a NO group. ) Here, the clay mineral is a smectite group mineral, which is a general term for silicate minerals with a three-layer structure.

The configuration and effects of the present invention will be explained in detail below.

The clay has a tetrahedral layer of silicon compound and 8 layers of aluminum compound.
It has a layered structure consisting of facepiece layers. Montmorillonite, in which some of the aluminum ions are replaced with magnesium or iron ions, lacks positive charges in the octahedral layers, and the charge density on the negatively charged 0-layer surface of the crystal as a whole is relatively thick, so there is a gap between each layer. Conditions for forming a complex that adsorbs water and is open, allowing the ionic organic compound to sneak between the layers to easily form a complex with the organic compound are not limited, but are, for example, as follows. First, the compound of the above formula (1) according to the present invention is added at a concentration of 0.001 to I mg/m
Make an aqueous solution of u water, preferably Q, 01-0.5a+g/mjl. Next, the aqueous solution was dissolved in an aqueous dispersion of clay (0,
1 to IOB/mfl water).

Although the mixing conditions are not limited, the mixture is stirred for 1 minute to 3 hours by mechanical stirring or ultrasonication at 0 to 50°C, preferably at room temperature. By this treatment, the spiropyran compound of formula (■) is adsorbed by 0.1 to 90%, usually from 1 to 50%.

The thus obtained adsorption mixture is subjected to dehydration filtration conversion (preferably under reduced pressure at room temperature) to obtain the composite material of the present invention. Then, the above-mentioned dehydration filtration is carried out using an appropriate filter (
For example, after applying it on a membrane filter),
By drying under reduced pressure at room temperature, the composite in the form of a film is obtained.

Since R in formula (1) is ionic, the compound represented by formula (1) can enter between the clay layers, replace inorganic cations, and be immobilized within the clay layers. The color of this complex is pale yellow, but when heated, the spiropyran compound opens its ring and has the formula (I+
) and develops color as a merocyanine compound.

When irradiated with visible light, this compound undergoes ring closure to become Compound (I) and decolorizes. The above-mentioned composite can be easily made into a film, and can be easily applied to a solid surface by dispersing it in a transparent paint or transparent ink as a powder, making it very practical.

In other words, by locally heating a film or surface coating film on which a photochromic compound is immobilized using a laser or the like, it is possible to locally develop color, and by scanning a laser beam, an arbitrary image can be recorded. can be displayed. Furthermore, images can be recorded and displayed by subjecting the film or surface coating film to color by heat treatment and then selectively irradiating the film with visible light.

[Effects of the invention] By immobilizing spiropyran compounds as a composite with clay minerals, it is possible to easily obtain a film or surface coating film that exhibits a photochromic effect. It is obvious that images can be recorded or erased by irradiation, greatly opening up the uses of photochromic compounds, and that their effects are great.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

i) Production of photochromic complex part 1) 6-nitro-1°,3°,3°-trimethylspiro[2tol-benzobilane-2,2°-indoline]
-8-(pyridinium)methyl chloride (Rnee0Q
c+-1 aqueous solution (115g/20mIt) 0.2.
2.0, 8. Omjl is an aqueous dispersion of clay (420-g
7100sf) 5 mft and visible light irradiation (340n
Mix by ultrasonication for 60 minutes while performing (a) above.

The adsorption rates of spiropyran to clay are 1%, 10%, and 40%, respectively, based on clay cation exchange capacity. Since the film-forming ability decreases as the adsorption amount of spiropyran increases, the maximum value was kept at 40%.

The obtained adsorption mixture was centrifuged, the supernatant liquid was discarded,
Filter the precipitate using a membrane filter under reduced pressure. When dried under reduced pressure at room temperature, the pale yellow clay-spiropyran complex peels off from the filter as a film.

Part 2) 6-nitro-1°,3°,3°-trimethylspiro[2+1-1-benzopyran-2,2°-indoline]-8-(N-methylpiperidinium)methyl chloride (420ag7100ml!) 5 Stir for 60 minutes by ultrasonication while irradiating visible light (340 nm or more) with mj2. The adsorption rate of spiropyran to clay is 1
It is 0%. The obtained adsorption mixture was post-treated in the same manner as above to obtain a film.

2) Color development experiment The film obtained by the method in 1) was heated at 63° C. for 30 minutes and exhibited the following colored state.

■6-nitro 1', 3° 3°-trimethyl spiro [21-1-1 This color development rate is the same as that of benzobylane-2,2-indolinco 8-(viridinyl in a sticky state) without forming a film and dispersing in water. When measured in this state, it is as follows.

■6-Nitro 1 benzobylane 3'-trimethylspiro[2) 1-1-indolinco-8-(N-methylbi1ii) The film-like clay composite colored in the decoloring experiment ii) was Corn-i
ng color filter (0-52) (> 3
40nm) with a 15QW halogen lamp.
When light Iq is irradiated from a distance of cm, the color of the film disappears to pale yellow in both cases.

The time required for decoloring is as follows.

Claims (1)

[Claims] (1) Composite material of ionic organic matter and clay mineral having the structure of the following formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (R in the formula is dialkylammonium salt or nitrogen-containing aromatic quaternary is a salt. X is C_nH_2_n_+_1 (n=0 to 10), O
C_mH_2_m_+_1 (m=1~10), NO_2
represents a group. ) Here, the clay mineral is a smectite group mineral, which is a general term for silicate minerals with a three-layer structure.