JP3979500B2 - Organic microcrystalline alignment dispersion, polarized fluorescent material, and production method thereof - Google Patents

Description

  The invention of this application relates to an organic microcrystalline orientation dispersion, a polarizing fluorescent material, and a method for producing the same. More specifically, the invention of this application relates to an organic microcrystalline orientation dispersion that is immobilized by inducing anisotropic orientation by applying a magnetic field or an electric field, a polarizing fluorescent material, and a method for producing the same.

  An organic microcrystalline orientation dispersion copolymer has been tried to be used as an optical material such as a color filter. In other words, the color filter method has been a typical method for full-color liquid crystal display devices in the past. However, the liquid crystal display device has a problem of a decrease in transmittance due to the color filter and the polarizing plate. In order to achieve this, for example, attempts have been made to use a color filter (PTL 1) having a polarizing function as a laminated structure.

  The polarization color filter is an important optical material in such a liquid crystal display device and the like, and studies are being made to improve the transmittance and polarization characteristics of the material constituting the polarization color filter.

  The inventors of this application pay attention to a dispersion system of an organic dye or an organic pigment as a material for such a polarizing color filter, and an organic dye or an organic pigment capable of improving transmittance and polarization function. A new polarizing color filter composed of a fine particle dispersion system and a manufacturing method thereof (Patent Document 2) have been proposed. The dispersion of ultrafine particles of organic dyes and organic pigments has electrical and optical anisotropy and isotropic overall dispersion, so organic second-order nonlinear optical materials and various optical and display materials It is because use as is expected.

However, the dispersion system proposed by the inventors is expected to be greatly developed in the future, but the approach to the best one has not yet been explored.
JP-A-8-286029 Application for Japanese Patent Application No. 2002-276179

  The invention of this application was made from the background as described above, and is useful as an optical material for a full-color liquid crystal display device and the like, and can improve transmittance and polarization function. As an approach, it is an object to provide an important new organic microcrystalline orientation-dispersed copolymer composed of a dispersion of organic pigment or organic pigment fine particles, a polarized fluorescent material, and a method for producing the same.

  In order to solve the above problems, the invention of this application is as follows. First, a fine crystal of an organic dye or an organic pigment may be anisotropically oriented by a magnetic field or an electric field and have a substituent. Disclosed is an organic microcrystalline alignment dispersion which is dispersed and fixed in a polymer medium comprising a monomer or oligomer of an alkyl acrylic acid.

  Second, an alkylacrylic acid monomer which may have a substituent is represented by the following formulas (1) and (2):

In the formula, R ¹ and R ⁴ are the same or different and each represents a hydrogen atom or a linear or branched alkyl group which may have a substituent, and R ² represents a substituent. R ³ represents a linear or branched alkyl group that may have a substituent, or may have a substituent, or may have a hetero atom intervened. (Shows alkylene chain)
And third, R ² is an organic microcrystalline alignment dispersion characterized by being an alkyl group having 7 or more carbon atoms. provide.

Further, the invention of this application, the fourth provides a polarized fluorescence material characterized by comprising the above organic crystallite orientation dispersion.

The fifth aspect of the invention of this application is that, as a method for producing the above-mentioned organic fine crystal alignment dispersion, a fine crystal of an organic dye or an organic pigment may be substituted with an alkylacrylic acid monomer which may have a substituent. or fixing medium oligomers are mixed, by inducing anisotropic orientation by a magnetic or electric field is applied to provide a method of manufacturing an organic crystallite orientation dispersion, which comprises immobilized by photocuring, the sixth Is an alkylacrylic acid monomer represented by the following formula (1) (2)

(In the formula, R ¹ and R ⁴ are the same or different and each represents a hydrogen atom or a linear or branched alkyl group which may have a substituent, and R ² represents a substituted group. Represents a linear or branched alkyl group which may have a group, and R ³ represents a linear or branched chain which may have a substituent or may have a different atom interposed 7) R.sup.2 is an alkyl group having a carbon number of 7 or more. Seventh, R ² is an alkyl group having 7 or more carbon atoms. provides a method of manufacturing an organic crystallite orientation dispersion, wherein, in the eighth fixing medium manufacturing method of the organic fine crystal orientation dispersion characterized by containing a photopolymerization initiator provide.

  The invention of this application as described above is useful as an optical material for a full-color liquid crystal display device and the like, and can improve the transmittance and the polarization function, and is important as an approach for the future. Provided are a novel organic microcrystal orientation dispersion comprising a dispersion of organic pigment fine particles, a polarized fluorescent material, and a method for producing the same.

  As described above, the organic microcrystalline orientation dispersion of the invention of this application is an external field such as a magnetic field or an electric field applied to a nanosized microcrystalline colloidal dispersion of an organic dye or organic pigment, as schematically illustrated in FIG. An organic microcrystalline orientation dispersion utilizing the microcrystalline anisotropic orientation effect induced by the application of. The microcrystalline anisotropic alignment effect of such an organic microcrystalline alignment dispersion is reversible and becomes isotropic when a non-external field is applied. In addition, in the oriented organic dispersion of the invention of this application, the microcrystals are immobilized in a specific polymer medium in an anisotropic state in the dispersion.

  An embodiment of the invention of this application having such characteristics will be described below.

  First, in the invention of the application, the organic dyes or organic pigments may be various ones including dyes and pigments for color filters used in liquid crystal displays, for example, regardless of the category of “dye” and “pigment”. . Preferable examples include styrylpyridinium dyes: DAST, poly 1,6-di (n-carbazoyl) -2,4-hexadiene: poly (DCHD), polycyclic aromatic compounds (anthracene, tetracene, pentacene, coronene) and the like. . Nanosized microcrystals of these organic dyes and organic pigments, that is, in the invention of this application, generally, microcrystals having a size of 1 μm (1000 nm) or less are first dispersed in a dispersion.

Here, the dispersion liquid is not particularly limited as long as the organic dye or the organic pigment can be dispersed. For example, a medium for immobilization described below may be used. In the case of preparing an organic microcrystal orientation dispersion dispersed and fixed in a dispersion, a fixing medium is used. The immobilization medium in this case is an organic polymer as described above, that is, an alkylacrylic acid monomer or oligomer optionally having a substituent as described above, and more preferably One or more of those represented by the formulas (1) and (2) are used. Among these, those that are crosslinked and cured by light are used. Specific examples of the monomer include, for example, linear or branched long-chain alkyl acrylic acid such as octyl acrylic acid, lauryl acrylic acid, lauryl methacrylic acid having an alkyl group having 7 or more carbon atoms, ethylene glycoloxyacrylic Examples thereof include diacrylic acid such as acid and fluorinated alkyl acrylic acid, and alkyl acrylic acid or alkyl methacrylic acid having various substituents such as halogen atom and alkoxy group. Here, by using an alkylacrylic acid monomer in combination with, for example, a diacrylic acid monomer derivative, the photocuring rate is improved and the immobilization is efficiently performed. Specific examples of diacrylic acid monomer derivatives include tricyclo [5.2.1.0 ^2,6 ] decane-4,8-dimethanol diacrylate, 1,3-butanediol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1 , 9-nonanediol diacrylate, 1,10-decanediol diacrylate, 2.2 Bis [4- (acryloxy polyethoxy) phenyl] propane, 2.2 Bis [4- (acryloxy diethoxy) phenyl] propane, Polyethylene glycol diacrylate, Dipropylene glycol diacrylate, Tripropylene glycol diacrylate Polypropylene glycol diacrylate, Neopentyl glycol diacrylate, 2-methyl-1,3-propanediyl ethoxy diacrylate. The amount of the diacrylic acid monomer derivative used is preferably several percent with respect to the alkylacrylic acid monomer, and preferably 1 to 2%, for example. As described above, these media are mixed using a photopolymerization initiator with a range and type that do not destroy the colloidal state in the dispersion.

  Examples of the photopolymerization initiator include azo compounds such as 2,2′-azobisisobutyronitrile (AIBN), peroxides such as benzoyl peroxide (BPO), trichloroacetophenone, and tris (trichloromethyl) -s. -Polyhalogen compounds such as triazine, acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ketones such as benzoin alkyl ether and benzophenone, organic compounds such as bispentadienyltitanium di (pentafluorophenyl) A metal compound is mentioned.

  In the invention of this application, a magnetic field or an electric field is applied in a state dispersed in such a dispersion to induce anisotropic orientation in the microcrystal. Alternatively, in the mixed state as described above, a magnetic field or an electric field is applied to induce anisotropic orientation in the microcrystal to solidify the fixing medium. As a result, after curing, a polymer that is transparent in the visible region and further excellent in processability can be obtained. Further, the magnetic field in this case may have an appropriate magnetic field direction and magnetic field strength. For example, the magnetic field strength is preferably as large as possible, and may be up to several tens of Tesla by a superconducting magnet. As for the electric field, anisotropic orientation is observed in both AC and DC, and the degree of orientation increases as the strength of the electric field increases. The AC frequency is preferably 10 Hz or more.

  According to the invention of this application as described above, an organic microcrystalline orientation-dispersed copolymer that is anisotropic under a magnetic field or an electric field is realized.

  The invention of this application also provides a polarizing fluorescent material comprising the organic microcrystalline alignment dispersion as described above. That is, as a result of intensive studies, the inventors of the present application have found that the above-described organic microcrystalline alignment dispersion is polarized and fluoresced, and have arrived at the present invention. For example, when the polarized fluorescent material is observed through a polarizer, a difference in emission brightness is observed depending on the angle of the polarizer. This polarized fluorescent material is composed of an organic microcrystal orientation dispersion in which organic microcrystals are anisotropically oriented by applying a magnetic field or electric field, and the magnetic field strength at the time of applying a magnetic field or electric field is set appropriately. By doing so, it is also possible to adjust the emission brightness.

  Therefore, examples will be shown below, and the embodiments of the invention will be described in more detail. Of course, the invention is not limited by the following examples.

  A styrylpyridinium dye (hereinafter abbreviated as DAST) microcrystal dispersion represented by the following formula was prepared by a reprecipitation method using lauryl acrylate (lauryl acrylic acid) as a dispersion. For photocuring, benzoin isopropyl ether as a photopolymerization initiator was added to a 0.1 mol / l microcrystalline dispersion and cured by irradiation with a mercury lamp while applying a magnetic field of 2 Tesla. When polarized light (0 deg.) Parallel to the direction of the magnetic field is incident on the immobilized DAST microcrystal dispersion system as shown in FIG. 2, an increase in absorbance is observed. When perpendicular polarized light (90 deg.) Was incident, a decrease in absorbance was observed as indicated by the triangle mark in FIG.

  The polarization absorption spectrum when the polarized light (90 deg.) Is incident on the DAST microcrystal dispersion that has been photocured without applying a magnetic field and polarized light (90 deg.) Is shown in FIG. As shown in Fig. 2, both agreed. Furthermore, even when a magnetic field was applied to the DAST microcrystal dispersion after photocuring, no change in absorbance was observed before and after application.

  Thus, the microcrystal dispersion solid which maintained the anisotropic orientation was obtained by photocuring the microcrystal dispersion under a magnetic field.

<Preparation and magnetic field orientation of anthracene microcrystal dispersion>
A sample obtained by recrystallizing commercially available anthracene from ethanol and sublimation purification was used. 0.1 ml of 5 mM purified anthracene acetone solution was poured into 5 ml of water to prepare a microcrystal dispersion. The absorption spectra of the anthracene ethanol solution and the anthracene microcrystal dispersion are indicated by circles and squares in FIG. 3, respectively.

  The absorption spectrum of the anthracene microcrystal dispersion was confirmed to be the same as the literature (Edward Van Keuren et.al, J.dispersion Sci.and Tech., 2003,24,721-729).

  Next, using an electromagnet capable of applying up to 2 Tesla, the polarization absorption spectrum of the anthracene microcrystal dispersion under a magnetic field was measured while changing the polarization angle (0 deg., 45 deg., 90 deg., 135 deg.). The polarization absorption spectrum was measured only for Vogt configuration. The results are shown in FIG. 4 ((a), (b), (c), (d)), respectively. Black circles in the figure indicate polarization absorption spectra when no magnetic field is applied, and white circles indicate polarization absorption spectra when a magnetic field is applied at 2 Tesla.

From FIG. 4, the polarization angle dependence was observed in the polarization absorption spectrum of the anthracene microcrystal dispersion under a magnetic field. In the Forked arrangement, when polarized light (0 deg.) Parallel to the magnetic field was incident under a magnetic field, a large increase in absorbance was observed in the entire measurement wavelength region (FIG. 4A). Conversely, when polarized light (90 deg.) Perpendicular to the magnetic field was incident under a magnetic field, a decrease in absorbance was observed in the entire measurement wavelength region (FIG. 4C). When the application of the magnetic field was stopped, the polarization absorption spectrum before the application was restored.
<Preparation and magnetic field orientation of microcrystalline dispersions of anthracene derivatives>
2-Anthracenecarboxylic acid (purchased from Tokyo Chemical Industry Co., Ltd.) dissolves when stirred in an equivalent amount of cesium hydroxide and water (H ₂ O), so the water is removed by lyophilization to produce a white solid (somewhat whitish crystals) Of 2-anthracenecarboxylic acid cesium salt (AnCO ₂ Cs) was obtained.

0.1 ml of 5 mM AnCO ₂ Cs methanol solution was poured into 5 ml of lauryl acrylate and heated little by little. When the solution became slightly cloudy and birefringence could be confirmed by laser light and a polarizer, the solution was left to room temperature to obtain a measurement sample.

The polarization absorption spectrum of an AnCO ₂ Cs microcrystal dispersion obtained by reprecipitation of this measurement sample in lauryl acrylate monomer under a magnetic field was measured while changing the polarization angle (0 deg., 45 deg., 90 deg., 135 deg.). The polarization absorption spectrum was measured in a fork arrangement and a Faraday arrangement (Faraday arrangement is only for polarization angles of 0 deg. And 90 deg.), And the results are shown in FIG. 5 ((a), (b), (c), (d)), This is shown in FIG. 6 ((a), (b)). Black circles in the figure indicate polarization absorption spectra when no magnetic field is applied, and white circles indicate polarization absorption spectra when a magnetic field is applied at 2 Tesla.

From FIG. 5, the polarization angle dependence was observed in the polarization absorption spectrum of the AnCO ₂ Cs microcrystal dispersion under a magnetic field. The orientation behavior was similar to unsubstituted anthracene. In the Forked arrangement, an increase in absorbance was observed in the magnetic field when polarized light (0 deg.) Parallel to the magnetic field was incident (FIG. 5 (a)), but the absorbance at the longest wavelength side did not change. It was. Conversely, when polarized light (90 deg.) Perpendicular to the magnetic field was incident, a decrease in absorbance was observed under the magnetic field (FIG. 5C).

  From FIG. 6, the same phenomenon was observed at all polarizer angles, and a decrease in absorbance was observed under a magnetic field. However, an increase in absorbance was observed at the absorption maximum. When the application of the magnetic field was stopped, the absorption spectrum before the application was restored.

<Fixed magnetic field orientation and fluorescence polarization behavior of microcrystalline dispersion of anthracene derivative>
0.1 ml of 5 mM AnCO ₂ Cs methanol solution was poured into 5 ml of lauryl acrylate and heated little by little. When the solution became slightly cloudy and birefringence could be confirmed by laser light and a polarizer, the solution was allowed to stand to room temperature. Next, benzoin isopropyl ether as a photoinitiator was added to 0.5 mM, and the dispersion was purged with nitrogen for about 10 minutes. The AnCO ₂ Cs crystallite dispersion was oriented and fixed by irradiating an ultrahigh pressure mercury lamp for about 10 to 15 minutes under a magnetic field and photocuring.

When this immobilized AnCO ₂ Cs microcrystal dispersion was irradiated with ultraviolet light, it was observed that the immobilized AnCO ₂ Cs microcrystal dispersion emitted light blue.

When the fluorescence of the AnCO ₂ Cs microcrystal dispersion system, the orientation of which was fixed at 2 Tesla, was observed through a polarizer, a difference in emission brightness was observed depending on the angle of the polarizer. However, it seems that the difference is clearer when cured under a magnetic field of 15 Tesla.

In order to measure stationary polarized fluorescence intensity, a sample immobilized in a four-sided transparent angle cell is required. For measurement, a fixed sample is set in the sample chamber of the fluorescence spectrometer, and first, excitation and fluorescence wavelength are set. The fluorescence intensity is measured by setting the angle of the polarizer on the excitation side and the fluorescence side to 0 ° (i _h ). The excitation side polarizer is left as it is, and the fluorescence intensity is measured by setting the fluorescence side polarizer to 90 ° ( _iv ). The fluorescence intensity is measured by setting the excitation-side and fluorescence-side polarizers to 90 ° (I _h ). The fluorescence intensity is measured by setting the excitation side polarizer to 90 ° and the fluorescence side polarizer to 0 ° (I _v ). The calculation of the degree of polarization (P) is obtained using the following equation.
P = (I _h −GxI _v ) / (I _h + GxI _v ), G = (i _v / i _h )
This time, the excitation wavelength was set to 366 nm, the fluorescence wavelength was set to 400 nm, and the degree of polarization was measured with an anthracene ethanol solution as a reference sample.
Anthracene ethanol solution: P = 0.047 at 400 nm
Oriented and fixed AnCO ₂ Cs crystallite dispersion system: P = −0.155 at 400 nm (first time), P = −0.113 at 400 nm (second time)
Comparison of molecularly dispersed solution systems showed that the degree of polarization of the orientation-fixed AnCO ₂ Cs microcrystal dispersion system was a large value, indicating polarized fluorescence due to orientation.

  In Example 1, instead of applying a magnetic field, curing was performed by irradiation with a mercury lamp while applying an electric field to prepare a DAST microcrystal dispersion. The applied electric fields were maximum AC 2.0 kV, 50 Hz, and DC 0.7 kV, respectively. When polarized light (0 deg.) Parallel to the electric field direction was incident on the solidified DAST microcrystal dispersion system in the Forked arrangement, an increase in absorbance was observed as in Example 1, and vertical polarized light ( When 90 deg.) Was incident, a decrease in absorbance was observed.

  The polarized light absorption spectrum when the parallel polarized light (0 deg.) Was incident on the DAST microcrystal dispersion system that was photocured without applying an electric field and the perpendicular polarized light (90 deg.) Were in agreement. Further, even when an electric field was applied to the DAST microcrystal dispersion after photocuring, no change in absorbance was observed before and after the application.

  Thus, a microcrystalline dispersion solid having anisotropic orientation was obtained by photocuring the microcrystalline dispersion even under an electric field.

<Electric orientation of anthracene microcrystal dispersion and anthracene derivative microcrystal dispersion>
The polarization absorption spectrum under an electric field was measured by changing the polarization angle (0 deg., 45 deg., 90 deg., 135 deg.) In the anthracene microcrystal dispersion liquid and the anthracene derivative microcrystal dispersion liquid prepared in Example 2. The applied electric fields were maximum AC 2.0 kV, 50 Hz, and DC 0.7 kV, respectively. From the result of the polarization absorption spectrum, the polarization angle dependency was observed as in Example 2. When the application of the electric field was stopped, the absorption spectrum before application was restored.

<Electric field orientation immobilization and fluorescence polarization behavior of microcrystalline dispersions of anthracene derivatives>
In Example 3, instead of applying a magnetic field, the AnCO ₂ Cs crystallite dispersion was oriented and fixed by photocuring with an ultrahigh pressure mercury lamp under an electric field. The applied electric fields were maximum AC 2.0 kV, 50 Hz, and DC 0.7 kV, respectively.

When this immobilized AnCO ₂ Cs microcrystal dispersion was irradiated with ultraviolet light, it was observed that the immobilized AnCO ₂ Cs microcrystal dispersion emitted light blue. When observed through a polarizer, a difference in emission brightness was observed depending on the angle of the polarizer.

It is the figure which illustrated typically the concept of the organic microcrystal orientation dispersion | distribution of invention of this application. FIG. 3 is a graph showing a change in absorbance of the immobilized DAST microcrystal dispersion produced in Example 1. It is the figure which showed the polarized light absorption spectrum of the anthracene ethanol solution produced in Example 2, and the anthracene microcrystal dispersion liquid. Forked anthracene microcrystal dispersion prepared in Example 2 was measured by changing the polarization angle ((a) 0 deg., (B) 45 deg., (C) 90 deg., (D) 135 deg.) In a forked arrangement. It is the figure which showed the spectrum. Fork arrangement of the AnCO ₂ Cs microcrystal dispersion prepared in Example 2 was measured by changing the polarization angle ((a) 0 deg., (B) 45 deg., (C) 90 deg., (D) 135 deg.). It is the figure which showed the polarization | polarized-light absorption spectrum. For Anco ₂ Cs microcrystalline dispersion prepared in Example 2, the polarization angle ((a) 0deg., ( B) 90deg.) Is a diagram showing a polarized absorption spectra of Faraday arrangement was measured by changing the.

Claims (8)

Organic fine crystals of organic dyes or organic pigments are anisotropically oriented by a magnetic field or an electric field, and are dispersed and fixed in a polymer medium from an alkylacrylic acid monomer or oligomer which may have a substituent. An organic microcrystalline orientation dispersion characterized by the above. The alkyl acrylic acid monomer which may have a substituent is represented by the following formulas (1) and (2):
(In the formula, R ¹ and R ⁴ are the same or different and each represents a hydrogen atom or a linear or branched alkyl group which may have a substituent, and R ² represents a substituted group. Represents a linear or branched alkyl group which may have a group, and R ³ represents a linear or branched chain which may have a substituent or may have a different atom interposed The organic microcrystalline orientation dispersion according to claim 1, wherein The organic microcrystalline orientation dispersion according to claim ² , wherein R ² is an alkyl group having 7 or more carbon atoms. A polarizing fluorescent material comprising the organic microcrystalline alignment dispersion according to claim 1. Organic dye or organic pigment microcrystals are mixed with an alkylacrylic acid monomer or oligomer fixing medium which may have a substituent, and anisotropic orientation is induced by application of a magnetic field or electric field to effect photocuring. A method for producing an organic microcrystalline orientation dispersion, comprising immobilization. The alkyl acrylic acid monomer which may have a substituent is represented by the following formulas (1) and (2).
(R in the formula ¹ And R ^Four Each independently represent a hydrogen atom or a linear or branched alkyl group which may have a substituent, and R ² Represents a linear or branched alkyl group which may have a substituent, and R ^Three Represents a linear or branched alkylene chain which may have a substituent or may have a different atom intervened). A method for producing an organic fine crystal alignment dispersion. R ² Is an alkyl group having 7 or more carbon atoms, The method for producing an oriented organic crystal dispersion according to claim 6. The method for producing an organic microcrystalline alignment dispersion according to any one of claims 5 to 7, wherein the fixing medium contains a photopolymerization initiator.