JPS6055038A - Photochromic resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which rapidly changes its color reversibly by light and gives a large contrast with respect to the color change, by blending bis-[2-(p-methoxy)phenyl-4,5-diphenyl imidazolyl] with a thermoplastic resin. CONSTITUTION:0.1-50pts.wt. bis-[2-(p-methoxy)phenyl-4,5-diphenylimidazolyl] of formula I is blended with 100pts. thermoplastic resin such as ethylcellulose resin or an acrylic resin to obtain a photochromic resin compsn. The compd. of formula I can be obtd. by condensing 2-(p-methoxy)phenyl-4,5-diphenyl-imidazole synthesized by reacting p-methoxybenzaldehyde with ammonium acetate in glacial acetic acid. When the compd. is exposed to sunlight, its color changes from water-whiteness to deep blue, while when light is screened, its color rapidly reverts to water-whiteness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photochromic resin composition that rapidly and reversibly changes color when exposed to light and that changes color with a large contrast.

In general, when a substance is irradiated with light such as ultraviolet rays or sunlight, the characteristic color of that substance changes significantly, and when the light is blocked, the property returns to its original color, which is called photochromism. Substances with this property have been developed and put into practical use, and typical organic substances include spiropyran compounds (for example, Japanese Patent Publication No. 51-4958
Inorganic substances such as titanium oxide and silver halide have been known for a long time, and salicylideneanyl is one that changes only in response to ultraviolet light. This photochromic substance is used for sunglasses, window glasses, photography-related goods, toys, etc., and is especially frequently used for sunglasses. Therefore, one of the essential 1R conditions required for a substance with photochromism is fast photoresponsiveness. That is, when exposed to light, the color changes immediately, and when the light is cut off, it quickly returns to the color of the tile, and the degree of discoloration is large. It is said that the harder the material has this kind of reversible change in response to light, the better it is, but the materials normally used for Xanglass are those whose response to light is slow < yil, -1-minutes\\. In most cases, even the most difficult ones took several minutes. Therefore, such materials could not keep up with instantaneous changes in light like the windshield of a car.

As a result of repeated research aimed at improving this drawback, the present inventor succeeded in synthesizing an organic compound that reacts strongly to light and changes color with an extremely large contrast, from colorless to deep blue. By blending this with a specific thermoplastic resin, a good photochromic resin composition can be provided, and a thin film made of this resin composition can be formed on a glass or plastic film -I-. J: It has become possible to create glasses or films with extremely high photochromism.

The details will not be shown below, but Bis(2,/1.5-triphenylimidazolyl) is an organic compound with photochromism that changes color from colorless to pink, but it is difficult to use in practical terms due to the small color change and small contrast. In addition, in the case of a nuclear substituted product in which an alkyl group such as a methyl group or an alkoxy group such as a methoxy group is introduced into all of the phenyl groups, in the case of a methyl group substituted product, the color is more pale purple than colorless, and the methoxy In the case of group-substituted products, the change was weaker in all cases, from colorless to green, and when light was blocked, it took more than 10 hours to return to the original color, making it completely impractical. However, the present inventor has developed bis-(2-(
We have found that p-methoxy)phenyl-45-diphenylimidazolyl is an organic compound with extremely high contrast and quick response to light. Next, we will discuss its manufacturing method.

Production example Benzyl 150 liters; p-methquin Benzaldehyde 84 parts Ammonium acetate 7 ()0 Ice shaved acetic acid 200 [1 part] Put two into a flask and put in a reflux condenser ('J' L addition?
I+:! l.

After dissolving, boil for about 1 hour. Next, when this is cooled and placed in a large amount of water, crystals are precipitated. The yield π was 200 parts. The formation of an imidazole ring from benzyl is based on the following formula.

CH-C-C-C6II5+2N113-I-CII:
, OC6■-140I■ 5 II II 0 2(p-methoxy)phenyl-4 obtained in this production example
The melting point of 5-diphenylimidazole is 221-222℃
Met.

The crystals were separated in a furnace, dried, and made with 20% potassium hydroxide.
Add 1,100 parts of methanol solution, put into the flask, add iW7 flow cooling filter again, and boil in a steam bath for about 1 hour. Next, transfer the contents to a large beaker and add 5% red blood salt.
When 300 parts of the aqueous solution is gradually added while stirring, the product precipitates out. This was separated in a furnace, washed with water and dried to obtain 200 parts of the structural formula (% 5-diphenylimidazolyl).The melting point of this compound was 206-21.0°C.

The powder of this compound, or the powder dissolved in toluene or methyl ethyl ketone, has remarkable photochromism, changing from colorless to deep blue when exposed to sunlight or ultraviolet light, and rapidly returning to its original colorless state when the light is blocked. This change can be explained using a structural formula as follows.

Colorless deep blue bis(2-(p-methoxy)phenyl 45-diphenylimidazolyl 1.1-2 (p-methoxyphenyl,
-/1.5-diphenylimidazolyl radical) This bis(2;(p-methoxy)phenyl4.5-diphenylimidazolyl) is hereinafter referred to as the subject dye.

In the present invention, the subject dye is blended into a synthetic resin, but it cannot be applied to all synthetic resins. For example, it cannot be used with urethane resins and epoxy resins because they react with them and lose their photochromic properties. It cannot be used at all for thermosetting resins such as melamine. Therefore, the synthetic resins to which this dye can be added are limited to thermoplastic resins, among which the best ones are acrylic resin, ethyl cellulose resin, saturated polyester resin, and vinyl chloride resin, and low-density polyethylene resin is also used. Available for use.

The most common method for blending the subject dye into these resins is to add and dissolve a predetermined amount of the subject dye into a solution containing a synthetic resin.By doing this, a thermoplastic resin solution having photochromism can be obtained. is obtained. In this case, the best solvents are aromatic hydrocarbons such as toluene and ketones other than acetone, and these solvents may be used alone or in combination. Specifically, toluene, methyl ethyl+ton, methyl in butyl ketone, etc. are preferable. Note that alcohol and acetoacetic acid ester cannot be used because they cause a reaction and cause loss of photochromism. The mixing ratio of the present dye and the synthetic resin is o, i parts to 50 parts, preferably 2 parts to 50 parts, more preferably 5 parts to 30 parts, per 100 parts of the resin. The solution consisting of the dye and synthetic resin obtained in this way is then processed by the casting method.
Alternatively, a photochromic molded article can be easily obtained by coating the surface of a film or glass. That is, a photochromic cast film can be obtained by pouring a solution consisting of a synthetic resin and a synthetic resin onto a roll onto a roll and drying it.On the other hand, coating methods include a dipping method, a bar coater method, a gravure printing method, and a screen method. There are printing methods, spray methods, etc., but the bar coater method and gravure printing method are used for the surfaces of 4V materials such as paper and film, and the dipping method is used for the surfaces of hard materials such as glass. , screen printing or spraying methods are suitable.

In order to protect the surface of a film or glass plate coated with a solution of the present dye and synthetic resin as described above, films or ζJ glass plates of the same or different types may be laminated. Of course, in this case, the laminating adhesive cannot be made of a synthetic resin that causes the photochromic properties mentioned above to be lost.

It is also possible to heat-mold the composition of the synthetic resin and the subject dye with or without adding a plasticizer, but if the heating humidity exceeds 200°C, decomposition may occur, so this molding method is not recommended. It is limited to synthetic resins that can be molded up to C, and the most one-step ones include a combination of PVC-based resin and a plasticizer, or low-density polyethylene.

Next, examples will be shown.

Example 1 This dye made by the manufacturing method shown in the text 10 parts Acrylic resin (A11, Worm & Hass Co., USA) I
0 parts Toluene 80 parts First, All is gradually added to toluene while stirring and completely dissolved. After dissolving, the entire amount is filtered through Japanese paper to remove fine dust and undissolved substances.Furthermore, 10 parts of the dyestuff is added thereto and slowly stirred to dissolve. In that case 40°C ~ 50°C
If the resin is heated to dissolve, it will dissolve quickly and a beautiful deep blue solution will be obtained.If this is cooled to room temperature and left in a dark place, it will become a colorless resin solution.

Apply this solution directly to a polyester film (thickness 50 microns) using an A12 bar coater to a thickness of 15 microns, and dry gently at 5ff' to 60°C.
A dry coating film of micron size is obtained.

This coating reacts extremely sensitively to light (sunlight or ultraviolet light) and turns deep blue in 2 to 3 seconds under direct sunlight (-19), and its transparency remains unchanged. Next, a piece of black paper was placed on top of this film to completely block sunlight, but it recovered to 50% in about 10 seconds, showing extremely good practicality.

Example 2 20 parts of the present dye 70 parts of DOP (dioctyl phthalate) Mix the present dye, Zeon Paste Resin 121, and DOP using an overmixer. If you have an over-the-top mixer to properly knead it, you can mash it in a mortar.Once you have a beautiful base, transfer it to a flask and use a low vacuum to remove the air contained in it, then put it in a mold and use I/IO°. ℃～170℃
Heat for about 10 minutes to gel the PVC PACE I resin.

When taken out and cooled, a beautiful transparent PVC molding is obtained.

When exposed to direct sunlight, it immediately turns blue, Example 1
A photochromic vinyl molded product with no change was obtained.

Example 3 5 parts of this dye 5 parts of low-density polyethylene G30690 parts manufactured by Sumitomo Chemical A beautiful blue-green molded product can be obtained by mixing the polyethylene pellets and this dye in a blender and immediately molding at a nozzle humidity of 170°C. When it is cooled, it becomes colorless and shows extremely good photochromic properties.

Example 4 This dye 2 parts Toluene 40 parts MEK 40 parts 6" Mix and dissolve by heating at 40°C to 60°C. Once dissolved, sieve through washi paper to completely remove fine dust and undissolved matter. .

This solution is printed on the entire surface of a polyester film (5 microns thick) using a 150 mesh gravure printing machine. If it is dried and rolled up, a long photochromic film can be obtained.

This film also turned blue when exposed to 1'' light, and had properties that were no different from those of Example 1.

agent Ben JTijshi 111th grade Hiroshi

Claims (1)

[Scope of Claims] Photochromic resin composition 2, characterized in that bis-(2-(T)smethoxy)phenyl-45-diphenylimidazolyl) represented by the following is blended into a thermoplastic resin: a thermoplastic resin Claim K is an ethyl cellulose resin, a saturated polyester resin, an acrylic resin, a vinyl chloride resin, a vinyl chloride-vinyl copolymer resin, and a polyethylene resin.
Resin composition 3 according to SJ item Claim 1, wherein the amount of bis(2;(+)7-methoxy)phenyl 145-diphenylimidazolyl) to the resin is 01 to 50 parts per 100 parts of resin. resin composition of