JPH0447686B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a novel photochromic copolymer capable of forming a film with excellent fading and coloring reversibility speed and durability. general formula The dithizone metal complex represented by (M is an n-valent metal) exhibits photochromism due to cis-trans isomerization and tautomerism as shown by the following formula. (In the formula, M is an n-valent metal) Such a dithizone metal complex has a degree of freedom for cis-trans isomerization and tautomerism of the photochromism mechanism as described above in an organic solvent such as benzene or chloroform. The reversible speed of color development and fading is fast, on the order of seconds. The reversible speed of color development and fading of this dithizone metal complex in a nonpolar solvent cannot be said to be superior to other photochromic compounds such as spiropyran and viologen, and the durability of reversible changes against ultraviolet light is poor. If it blocks the ultraviolet rays, it is far superior to other photochromic compounds such as spiropyran and viologen in terms of durability of reversible changes. For example, a spiropyran type shows only about 20 reversible changes, but a dithizone metal type shows a reversible change of more than 10,000 times when used in combination with an ultraviolet absorber. As described above, dithizone metal complexes contain iodine, which is important as a photochromic compound, in nonpolar solvents, and have attracted attention from an early stage, and attempts have been made to apply them in solid matrices such as polymers. However, since the dithizone metal complex exhibits photochromatic performance due to cis-sutroant isomerization and tautomerism, simply dispersing it in a solid matrix such as a polymer matrix eliminates this degree of freedom, and color development and fading are reversible. The speed becomes extremely slow and the sensitivity to light irradiation becomes dull. As a result of intensive research to improve the photochromic properties of the dithizone metal complex in the above-mentioned polymer matrix, the present inventor discovered that a dithizone metal complex having a vinyl group or a divinyl group and an unsaturated nomoner copolymerizable with it. It has been discovered that a copolymer increases the degree of freedom of the dithizone metal complex in a polymer matrix and is suitable for the purpose, and based on this knowledge, the present invention was accomplished. That is, the present invention involves copolymerizing a dithizone metal complex represented by the following general formula () or () and a monofunctional unsaturated monomer copolymerizable with the dithizone metal complex in the presence of a radical polymerization initiator. A method for producing a copolymer, characterized by: (However, in the above formulas () and (), R is a hydrogen atom, a halogen atom excluding fluorine, and a carbon atom number of 1
~5 alkoxy group, an alkyl group having 1 to 10 carbon atoms, or a haloalkyl group, and M is an n-valent metal. ) It is preferable that the proportion of polymerized units derived from the dithizone metal complex to the copolymer is 0.001 to 70% by weight. In addition, in the general formula () or () above, M may be any n-valent metal without particular limitation, but representative metals exhibiting photochromatic performance include known metals exhibiting photochromic performance, such as
Pd, Ag, Hg, Zn, Cd, Pd, Pt, Bi, etc. are especially
Hg, Pd, Zn and Ag are preferably used. Furthermore, R in the general formula () is a hydrogen atom; a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom; an alkoxy group having 1 to 5 carbon atoms such as a methoxy group, an ethoxy group, a propoxy group, a butoxy group, or a pentoxy group; Group: Alkyl group having 1 to 10 carbon atoms such as methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group; Chlorine atom, bromine atom, iodine atom or fluorine atom with one hydrogen atom A haloalkyl group consisting of the above alkyl group partially or fully substituted is preferably used. The dithizone metal complexes are generally colored crystalline solids at room temperature and pressure, and some metal complexes exhibit photochromism even in their crystalline state, and are also highly soluble in organic solvents, such as benzene, chloroform, etc. The solution shows photochromism when exposed to visible light. Further, by changing R in the general formula () in this manner, the color tone of the photochromic compound during color development and fading can be changed, that is, the absorption wavelength can be shifted. For example, when R in the general formula () is an electron-donating group such as an alkoxy group or a halogen atom other than fluorine, the absorption wavelength of the photochromic compound can be shifted to the longer wavelength side. Furthermore, if necessary, a substituent can also be introduced into the other aromatic ring having a vinyl group in general formula (). Furthermore, these dithizone metal complexes are generally colored crystalline solids at room temperature and pressure, and some metal complexes exhibit photochromism even in their crystalline state, and are also highly soluble in organic solvents, such as benzene, chloroform, etc. A solution dissolved in will exhibit photochromism when irradiated with visible light. In addition, as described above, there is a tendency that the reversible speed of color development and fading is generally a little slow. Further, the other polymerized units of the polymer of the present invention are derived from monofunctional unsaturated monomers copolymerizable with the dithizone metal complex, and the monomers used to provide the polymerized units are not particularly limited and may be used. In general, the following monomers are suitable. (a) General formula

Monomer represented by [Formula]. (However, in the formula, X is a hydrogen atom or a halogen atom, Y is a hydrogen atom, a halogen atom, or a methyl group, and R ¹ is an alkyl group having 1 to 10 carbon atoms or a phenyl group.) (B) General A monomer represented by the formula _CH2 =CX- ^R2 . (However, in the formula, X is a hydrogen atom or a halogen atom, and R ² is a halogen atom, a hydroxyl group, or a nitrile group.) (C) General formula

Monomer represented by [Formula]. (However, R ³ is an alkyl group having 1 to 10 carbon atoms.) (d) General formula A monomer indicated by . (However, R ⁴ is CH ₂ or OCH ₂ , X is a hydrogen atom or a halogen atom, and n is 0 or 1) The present invention has a vinyl group represented by the above general formula () or (). The ratio of polymerized units derived from dithizone metal complex to copolymer is 0.001
It is recommended to copolymerize to ~70% by weight, preferably 0.002 to 50% by weight, more preferably 0.005 to 30% by weight, and if the proportion of the added amount of this dithizone metal complex is less than 0.001% by weight, the color density will decrease. If the amount exceeds 70% by weight, the degree of freedom of the dithizone metal in the polymer matrix decreases, and the reversible speed of color development and fading becomes slow. The monofunctional unsaturated monomer used in the present invention may be any monomer that can be copolymerized with the dithizone metal complex having a vinyl group represented by the above general formula () or (). Specifically, methyl acrylate, ethyl acrylate,
Propyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, phenyl methacrylate, stearyl methacrylate, styrene,
Vinylpyrrolidone, vinyl acetate, vinyl butyrate, vinyl alcohol, vinyl chloride, vinylidene chloride,
Acrylonitrile, vinyl chloroacetate, methyl chloroacrylate, propyl chloroacrylate, butyl chloroacrylate, chloracrylic acid-sec
-Butyl, cyclohexyl chloroacrylate, allyl alcohol, allyl chloride, benzyl allyl carbonate, allyl cinnamate, phenoxyethyl allyl carbonate, metabromobenzyl allyl carbonate, phenyl allyl carbonate, etc., especially when the glass temperature is around room temperature. It is preferable to use methyl acrylate, ethyl acrylate, ethyl methacrylate, vinyl acetate, vinyl butyrate, etc., which have the following properties and can yield soft copolymers. As the radical polymerization initiator, for example, a non-oxidizing initiator such as azobisisobutyronitrile (AIBN) is preferably used. A typical method for producing the photochromic polymer of the present invention is shown. First, the above general formula () or ()
A dithizone metal complex having a vinyl group represented by: alcohols such as methanol, ethanol, and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethers such as ethyl ether, dioxane, and tetrahydrofuran, ethyl acetate, and n-butyl acetate. esters such as benzene, toluene, xylene, acetonitrile, dimethylformamide,
Dissolves in various solvents such as dimethyl sulfoxide and chloroform, and mixed solvents thereof. Then,
A copolymerizable monofunctional unsaturated monomer is dissolved in the above solvent, and AIBN is added as a polymerization initiator in an amount of 0.01 to 0.05% by weight based on both monomers.
Amble polymerization is carried out in a N ₂ sealed tube at ℃ for 40 to 80 hours, and the resulting photochromic polymer is washed with distilled water before use. A photochromic film is obtained by dissolving the photochromic polymer thus obtained in the above-mentioned solvent again and forming a film on a slide glass. This photochromic film is normally colored yellow or orange, but when irradiated with visible light, it immediately develops a strong color.
The color changes to blue or purple. Furthermore, if left in a dark place after color development, it immediately returns to its original yellow or orange state, and if only ultraviolet rays can be blocked, this reversible change in color development and fading will occur on the order of seconds and will be repeated over 10,000 times. . The photochromic polymer of the present invention having these properties can be used in a wide range of fields, including various recording and storage materials in place of silver salt photosensitive materials, copying materials, photoreceptors for printing, recording materials for cathode ray tubes, and photosensitive materials for lasers. It can be used as a variety of recording materials, such as photosensitive materials for holography. Further, these photochromic polymers can be made into a film and, for example, sandwiched in a plastic lens to form a photochromic lens. In addition, the photochromic polymer of the present invention can be used as a material for, for example, optical filters, display materials, masking materials, photometers, decorations, and the like. The present invention will be explained in more detail below using Examples and Comparative Examples. The method for measuring the photochromic properties of the photochromic films used in Examples and Comparative Examples is as follows. Γ Method for measuring photochromic characteristics Toshiba sunlight lamp DR-400/T at 25±1℃
The film was irradiated for 90 seconds at a distance of 10 cm under the following temperature conditions to develop color and its photochromic properties were measured. The photochromic characteristics were expressed as follows. Maximum absorption wavelength (λmax): λmax of this coloring film using a spectrophotometer 220A manufactured by Hitachi, Ltd.
I asked for ε (90 seconds): Absorbance at the maximum absorption wavelength corrected for the film thickness during 90 seconds of light irradiation of this film under the above conditions ε (0 seconds): At the maximum absorption wavelength at the time of light irradiation,
Thickness-corrected absorbance of a fully irradiated film Half-life t1/2: After 90 seconds of light irradiation, the absorbance of this film is 1/ of {ε (90 seconds) - ε (0 seconds)}
The photochromic characteristics are expressed by λmax, ε (90 seconds), ε (0 seconds), and t1/2, which are longer than the time required for the temperature to decrease to 2. Example 1

4 mg (0.0052 mmol) of dithizone mercury having a vinyl group represented by the formula
was subjected to amble polymerization in a N ₂ sealed tube at 50° C. for 72 hours in 1.00 g of ethyl acrylate and 4 ml of N,N-dimethylformamide (DMF) using 0.02 g of AIBN as a polymerization initiator. The resulting dark red photochromic polymer was washed with distilled water. The yield was 99.8%. Therefore, the amount of dithizone mercury contained in the polymer matrix is 3.99 mg. Thereafter, this photochromic polymer was dissolved in 5 ml of chloroform, a film was formed on a slide glass (1.2 x 3.7 cm), and dried at room temperature in a vacuum of 1 torr for 2 hours.
A cast film was prepared and the photochromic properties of this film were measured. The results are shown in Table 1. Examples 2 to 4 Photochromic films were prepared by polymerization in the same manner as in Example 1, except that the amount of dithizone mercury having a vinyl group was changed, and the photochromic properties thereof were measured. The results are shown in Table 1. Examples 5 to 12 Polymerization was carried out in the same manner as in Example 1 except that other unsaturated monomers were used in place of ethyl acrylate, photochromic films were prepared, and their photochromic properties were measured. Table 1 shows the results.
Shown below. Comparative Example 1 3.80 mg (0.0054 mmol) of dithizone mercury was dissolved in 1.0 g of polyethyl acrylate and 5 ml of chloroform, formed into a film on a slide glass, and heated at room temperature.
A cast film was prepared by drying in a vacuum of 1 torr for 2 hours, and the photochromic properties of this film were measured. The results are shown in Table 1. Comparative Examples 2-3 The same procedure as Comparative Example 1 was carried out except that the amount of dithizone mercury was changed. The results are shown in Table 1. Comparative Examples 4 to 6 Table 1 shows the results of the same procedure as Comparative Example 1 except that another polymer was used instead of polyethyl acrylate.

【table】

【table】 Example 13

A photochromic film was prepared by polymerizing 2.2 mg (0.0053 mmol) of dithizone silver having a divinyl group represented by the formula with 1.0 g of vinyl acetate in the same manner as in Example 1.
Its photochromic properties were measured. The results are shown in Table 2. Example 14

1.6 g (0.0019 mol) of dithizone palladium having a vinyl group represented by the formula
was polymerized with 1.0 g of styrene in the same manner as in the example,
A photochromic film was made and its photochromic properties were measured. The results are shown in Table 2. Example 15

1.0g of dithizone zinc having a vinyl group represented by the formula
(0.0015 mol) was polymerized with 1.0 g of vinyl alcohol in the same manner as in Example 1 to prepare a photochromic film, and its photochromic properties were measured. The results are shown in Table 2. Example 16

Dithizone mercury having a vinyl group represented by the formula: 0.82g
(0.988 mmol) was polymerized with 1.0 g of vinylpyrrolidone in the same manner as in Example 1 to prepare a photochromic film, and its photochromic properties were measured. The results are shown in Table 2. Example 17 1.0g of dithizone zinc having a vinyl group represented by
(0.0015 mol) and benzyl allyl carbonate 1.0
g was polymerized in the same manner as in Example 1 to form a film, and its photochromic properties were measured. The results are shown in Table 2. Comparative Examples 7-11 Comparative experiments corresponding to Examples 13-17 were conducted in the same manner as Comparative Example 1. The results are shown in Table 2.

【table】

Claims (1)

[Scope of Claims] 1. A dithizone metal complex represented by the following general formula () or () and a monofunctional unsaturated monomer copolymerizable with the dithizone metal complex in the presence of a radical polymerization initiator. A method for producing a copolymer characterized by polymerization. (However, in the above formulas () and (), R is a hydrogen atom, a halogen atom excluding fluorine, and a carbon atom number of 1
~5 alkoxy group, an alkyl group having 1 to 10 carbon atoms, or a haloalkyl group, and M is an n-valent metal. 2. The method for producing a copolymer according to claim 1, wherein the proportion of polymerized units derived from the dithizone metal complex to the copolymer is 0.001 to 70% by weight. 3 Metal (M) is Pd, Ag, Hg, Zn, Cd, Pb,
A method for producing a copolymer according to claim 1, which is one selected from Pt and Bi.