JPS6177846A - Photochromic material - Google Patents

Abstract

PURPOSE:To provide a photochromic material good in durability by incorporating a clathrate compd. composed of the guest molecule of a photochromic substance and a host molecule. CONSTITUTION:A preferable host molecule is cyclodextrine and the photochromic substance is spiropyran, dithizone mercury complex, triphenylmethane type dye, fulgide, etc. are used. The clathrate compd. is prepared by adding the photochromic substance to an aq. soln. of cyclodextrine at least in an amt. of >=10mol%, mixing them at room temp., grinding down at once and well stirring them, then, filtering and washing them, and drying them in reduced pressure. The photochromic material is formed into a soln. by using a solvent, such as xylene or toluene, and its solid soln. is obtained by using an org. polymer, such as PMMA or polystyrene. It is preferable for the clathrate compd. to be contained in an amt. of 0.0001-15wt% in a medium in order to cause the photochromic material to develop color by light irradiation.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to photochromic materials, particularly organic photochromic materials.

[Conventional technology]

Conventionally, there has been extensive research on photochromic compounds, and limited to organic compounds, spiropyran, triphenylmethane dye leuco, imidazole, incif, thioindico, dinitrobenzyl, pyridine, furquito,
Stilbenes, heterocyclic compounds, fused polycyclic aromatic compounds, etc. are being investigated.

Particularly regarding spiropyran, numerous studies have been conducted in liquids and resins, and attempts have been made to improve its effectiveness.

Regarding fused polycyclic aromatic compounds, research and development have been conducted on systems in which they are dispersed in various fattening media such as epoxy resins, polyvinyl chloride, polymethyl methacrylate, and polycarbonate. (JP-A Showa t9-/l≠≠33, JP-A Showa 3
;! ;-/! ;/! ;/za) [Problems to be Solved by the Invention] However, these conventional photochromic materials have a drawback in durability, and so far no photochromic material with good durability that can be put into practical use has been reported.

An object of the present invention is to provide a photochromic material with good durability, and this object is achieved by the present invention.

[Means for solving problems]

That is, the present invention is a photochromic material containing an inclusion compound having a photochromic substance as a guest molecule.

The host molecule in the clathrate compound used in the present invention needs to have a size suitable for incorporating (ie, clathrating) seven molecules of the photochromic substance as guest molecules. Cyclodextrin is preferred as this host molecule, and cyclodextrin has 6, 7, and 7 glucose molecules. α, β, and
There are three types of r-cyclodextrin. The inner diameters of these cavities are λ, 7~λ, and 9~/(7), respectively.

The seven molecules of the photochromic substance, which are guest molecules, need to be of a suitable size to be included in the corresponding cyclodextrin. Spiropyran, dif-sine mercury complex, triphenylmethane dye, fulgide, etc. are used as photochromic substances which are guest molecules.

The clathrate compound in the present invention is usually a solid.

It is most preferable that this clathrate compound has the same number of host molecules and guest molecules, but if it has at least 10% of the guest molecules of the photochromic substance based on the number of host molecules, the desired color development/decolorization can be achieved. It will be done.

To produce the clathrate compound of the present invention, a photochromic substance is added to an aqueous cyclotextrin solution, mixed at room temperature, and then immediately ground and stirred well. Thereafter, a clathrate compound of the photochromic substance (Sifurobukis) precipitates, which is collected by filtration, washed, and then dried under reduced pressure. In this way, the desired clathrate compound can be obtained in powder form.

The photochromic material of the present invention preferably contains a medium for molecularly dispersing the clathrate compound.

If a liquid such as xylene or toluene is used as a medium for the clathrate compound, the photochromic material becomes a solution, and if an organic polymer such as polymethyl methacrylate or polystyrene is used, the photochromic material becomes a solid solution. In order for the photochromic material to develop and fade in color upon irradiation with light (for example, sunlight) and cessation of irradiation, it is preferable that the clathrate compound be contained in an amount of 0.000/wt% to/jet% based on the medium.

[Action and effect of the invention]

According to the present invention, it is possible to obtain a photochromic material in which a host molecule includes a photochromic substance, which has not been seen heretofore. Compared to the conventional case in which a photochromic substance is directly dispersed in molecular form in a medium without using host molecules, in the case of the present invention, in which an inclusion compound in which a photochromic substance is included in a host molecule is dispersed in a molecular form in a medium, the photochromic material The durability of the photochromic material is improved, and the color of the photochromic material becomes lighter when irradiated with light. Although the reason for the improvement in durability is not clear, it is thought that the deterioration in durability is mainly due to the interaction between the photochromic substance and the medium. It is presumed that this is prevented by the substance, thereby improving durability.

The present invention will be explained in more detail with reference to Examples below.
It goes without saying that this does not limit the scope of the present invention.

〔Example〕

Example / τ-cyclodextrin (manufactured by Tokyo Kasei) 10 g of water
When g was added and stirred, it became a slurry. This was synthesized by a known method /,3,3-trimethylindolino-≦'-nitro,! Add 1 g of '-methoxybenzobilylsubirane (compound (I)), mix at room temperature, and immediately mash and stir well. The precipitated clathrate compound was filtered and washed with xylene. Thereafter, the product was dried under reduced pressure to obtain a clathrate compound containing approximately the same number of guest molecules (compound (I)) and host molecules (r-sifurobukis). A solution of 0.01 g of this clathrate in xylene 10100O (Oxt o -6m
ol/l) and the equivalent concentration of compound (I) (+!;
6m0J? /l) of xylene solution to a thickness of 2
It was placed in a 0 mm Pyrex container. Under fluorescent light, the former was a paler yellow than the latter, but under sunlight it became a similar deep blue.

When visually observed under sunlight, the latter color lost its blue color after about 1 hour and 1j minutes, but the former color remained open at about 5 o'clock. In other words, inclusion improved the durability period by about four times.

Example 2 An experiment similar to Example 1 was conducted using β-cyclodextrin (manufactured by Tokyo Kasei). Due to clathration, the color becomes pale under fluorescent light, and the durability period is increased by about 3 times.

Example 3 An experiment similar to Example 1 was conducted using β-cyclodextrin and l-amino-core 6-dichloro-phenylmercury dithizonate (Compound (II)). Due to clathration, the color became lighter under fluorescent light, and the durability period was increased by about 3 times.

Example≠ An experiment similar to Example 1 was conducted using r-cyclodextrin and compound (AE). Due to clathration, the color becomes pale under fluorescent light, and the durability period is approximately doubled.

Example S An experiment similar to Example 1 was conducted using α-cyclodextrin and l-amino-7 enylmercury dithizonate.

Due to clathration, the color became lighter under fluorescent light, and the durability period was increased by about 3 times.

Claims (3)

[Claims] (1) Photochromic material containing an inclusion compound consisting of a guest molecule and a host molecule, which are photochromic substances (2) The photochromic material according to claim 1, wherein the host molecule is cyclodextrin. (3) The photochromic material according to claim 1, wherein the photochromic substance is spiropyran, a dithizone metal complex, a triphenylmethane dye, or fulgide.