JP4858758B2 - Rhodamine compounds - Google Patents

Description

  The present invention relates to a novel rhodamine compound having excellent heat resistance and light resistance. More specifically, the present invention relates to colors of light emission colors such as a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence display (ELD), a cathode ray tube display (CRT), and a field emission display (FED). Rhodamine dyes useful as optical filter materials to be installed to improve purity, or rhodamines useful as optical filter materials to be used to prevent reflection and reflection of fluorescent lamps normally used indoors It relates to a system dye.

  Image display devices such as plasma display panel (PDP), liquid crystal display (LCD), electroluminescence display (ELD), cathode ray tube display (CRT), field emission display (FED) are red, green and blue A color image is displayed with a combination of three primary colors of light. However, in these displays, excessive light is included in the light emitted from the phosphor due to the characteristics of the light emitter, so that the green portion and the red portion cannot be accurately reproduced. Therefore, in order to make the contrast of the image clear, a filter using a dye having absorption in the wavelength range is used in order to cut light having an unnecessary wavelength in the range of 540 nm to 600 nm. Furthermore, in order to maintain the sharpness of the contrast of the display image, a function for preventing reflection and reflection by light of 540 nm to 560 nm due to external light such as a fluorescent lamp is also required.

  In order to suppress the light having an excessive emission wavelength near 550 nm and prevent reflection and reflection due to external light of 540 nm to 560 nm, it is effective to use a dye that selectively absorbs light of that wavelength. Optical filters that do not transmit light in a specific wavelength band are proposed in Patent Document 1, Patent Document 2, and Patent Document 3 described below.

  However, the dyes disclosed in these prior arts have a high probability of changing over time due to deterioration due to light and have insufficient stability. Moreover, in the optical filter using the pigment | dye currently disclosed by prior art, the room for improvement is left in the durability.

  On the other hand, rhodamine compounds such as rhodamine B, rhodamine 6G, rhodamine 3B, rhodamine F, rhodamine 101, rhodamine 110, rhodamine 116, rhodamine 123 and the like can be mentioned as compounds exhibiting strong absorption in the range of 500 nm to 600 nm. Patent Document 4 below proposes that rhodamine dyes whose structures have been modified to take advantage of these properties are widely used as dyes for light absorbers, optical recording materials, and the like.

International Publication WO00-23829 JP 2005-331545 A JP 2005-194509 A Japanese Patent Laid-Open No. 2005-2290

  The rhodamine-based compound is formed from a dye cation and an anion having an extended π conjugate. The dye cation was not fully satisfactory in terms of light resistance and heat resistance, such as absorption wavelength change due to decomposition reaction caused by light, oxygen, ozone, etc. and dye skeleton breaking.

Problems to be solved by the invention

  An object of the present invention is to provide a rhodamine compound having excellent light resistance and heat resistance and having high solubility in a solvent, a resin, an adhesive, and the like. In addition, it selectively cuts light of a specific wavelength of 540 to 600 nm generated in various displays, particularly a plasma display panel, and selects light of a specific wavelength of 540 nm to 560 nm to suppress reflection and reflection of external light. It is an object of the present invention to provide a rhodamine dye that cuts in an effective manner.

Means for solving the problem

  The present invention relates to a rhodamine compound represented by the following general formula (1).

(Wherein R1 and R2 are each independently an unsubstituted or substituted aryl group having 6 to 24 nuclear carbon atoms. Examples of the aryl group having 6 to 24 nuclear carbon atoms include a phenyl group, A naphthyl group, a biphenyl group, a terphenyl group, a pyridyl group, etc. In addition, about the substituent which may be introduce | transduced into this aryl group, a methyl group, an ethyl group, n-propyl group, isopropyl group, n-butyl group , Isobutyl group, sec-butyl group, t-butyl group, pentyl group, hexyl group, and halogen (F, Cl, Br, I).
In addition, the benzene ring to which —CONR1R2 is bonded is the same as the aryl group of R1, such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, t-butyl group. Group, pentyl group, hexyl group, halogen substituent R3 may be introduced. X- represents a counter ion, and examples thereof include a halogen ion, a boron-containing complex ion, a metal complex ion, and a peroxide ion. Specific examples include the following anions. Ph represents a phenyl group. )

The invention's effect

  The rhodamine compound of the present invention is excellent in light resistance and heat resistance, and exhibits high solubility in organic solvents, resins, adhesives, and the like, and therefore is suitable for use as a dye that absorbs light at 540 nm to 600 nm. Specifically, the light resistance and heat resistance are improved by introducing a 2,6-xylylamino group, and the absorption wavelength is adjusted to an appropriate λmax by introducing a diarylamide group. The rhodamine-based compound of the present invention is used for the color of light emitted from a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence display (ELD), a cathode ray tube display (CRT), a field emission display (FED), etc. When used as an optical filter material that is attached to improve purity, or as an optical filter material that is attached for the purpose of preventing reflection or reflection of fluorescent lamps normally used indoors, Excellent durability without causing decomposition due to reaction with light.

  The rhodamine-based compound according to the present invention efficiently transmits light relating to the three primary colors of red, green, and blue, and selectively and efficiently absorbs light of 540 nm to 600 nm, particularly 540 nm to 560 nm. When used as a pigment for optical filters installed in the LCD, the color purity can be improved without interfering with the required light emission of the three primary colors red, blue and green from the display panel. The screen can be made clearer since it can prevent the reflection and reflection.

The present invention is described in detail below.
Specific examples of particularly preferred dye cation components of rhodamine compounds include the compounds shown below.

また、本発明のローダミン系化合物のアニオン成分の具体例としては、例えば下記に示すアニオン化合物が挙げられる。

Specific examples of the anion component of the rhodamine compound of the present invention include the following anion compounds.

  The method for producing the rhodamine-based compound represented by the general formula (1) of the present invention is not particularly limited, and can be obtained by a method using a known general reaction. For example, a dye cation moiety can be obtained by reaction of 3,6-di (2 ′, 6′-xylyl) rhodamine and a secondary amine, and then an anion exchange reaction proceeds by reaction with a salt compound. Conversion to other anions is possible. For example, it can be obtained by the following reaction formula (2) or (3).

  The rhodamine compound of the present invention is an image display device such as a plasma display panel (PDP), a liquid crystal display device (LCD), an electroluminescence display (ELD), a cathode ray tube display device (CRT), a field emission display (FED), etc. It may be used as a pigment for an optical filter used in the invention, and is suitable for use as a pigment that absorbs light in the range of 540 nm to 600 nm. The optical filter is required to have selective absorption of light of 540 to 600 nm, particularly 540 to 560 nm, and this is usually used indoors at the same time as preventing the contrast of the green image from becoming blurred. It is attached for the purpose of preventing reflection and reflection of fluorescent lamps. For this reason, the rhodamine-based compound according to the present invention is described in detail below, but it is preferable that a decrease in transmittance occurs in the vicinity of a wavelength of 550 nm when processed into an optical filter. If the decrease in transmittance deviates from the above range, there is a risk of preventing transmission of pure red light (630 nm) or green light close to the wavelength on the orange light side, and sufficient red light and green light cannot be extracted. This is because the color purity may not be achieved and the image may be unclear.

  A method for producing a contrast enhancement filter, anti-reflection filter and antireflection filter using the rhodamine dye of the present invention as a dye for a display optical filter is not particularly limited. Two methods are available.

  That is, (i) a method of kneading a resin for a display optical filter in a resin and thermoforming it to produce a resin plate or film; (ii) a paint (liquid or paste) containing a pigment for a display optical filter; A method of producing and coating on a transparent resin plate, transparent film or transparent glass plate; and (iii) A dye for display optical filter is contained in an adhesive or an adhesive, and a laminated resin plate, a laminated resin film, a laminated glass, or the like And the like.

  This display filter can be installed in front of the display as a display filter that selectively and efficiently absorbs light of 540 to 560 nm, increases color purity, and prevents reflection and reflection. If the selective absorptivity of light of 520 to 560 nm, particularly less than 530 nm, is low, the image may be unclear.

  When the rhodamine-based compound of the present invention is used for an optical filter for image display, the optical filter is usually disposed on the front surface of a light-emitting element having a plurality of light-emitting portions that can be controlled independently. Light emitting elements that can be used include a plasma display panel (PDP), a liquid crystal display (LCD), an electroluminescence display (ELD), a cathode ray tube display (CRT), a field emission display (FED), and the like. For example, the optical filter may be directly attached to the surface of the light emitting element. When a front plate is provided in front of the light emitting element, a film is attached to the front side (outside) or back side (light emitting element side) of the front plate. In addition, the front plate may be an optical filter.

Production Example 1 Production of Rhodamine Compound B by Diphenylamidation of Rhodamine Compound A 8.92 g of 3,6-di (2 ′, 6′-xylyl) rhodamine, 3.77 g of diphenylamine, 19.5 g of triethylamine, toluene 145 g was charged into the flask, and 11 g of phosphorus oxychloride was added dropwise at room temperature. The entire mixture was heated to 85 degrees and stirred for 3 hours. After cooling to room temperature, the reaction mixture was discharged into 500 g of ice water. The organic phase was separated, washed with water and dehydrated, and 130 g of hexane was slowly added. The separated tar-like amidated product is mixed with hexane and stirred for 12 hours, and the precipitated crystals are collected by suction filtration, dried at 70 to 80 ° C., and rhodamine compound B having a chloride ion as a counter anion is obtained. Obtained in 94.4% yield.

(Production Example 2) Production of rhodamine compound C 8.00 g of rhodamine compound B was dispersed in 135 g of methanol, and sodium borane-bis (3,5-di-t-butyl salicylate dissolved in 28.0 g of methanol. ) 5.90 g was added dropwise over 10 minutes. After stirring for 6.5 hours, it was slowly discharged into 1 kg of water, and 50 g of sodium chloride was added. The precipitated crystals were collected by suction filtration and washed with water. After drying at 65 ° C. and also at 100 ° C., rhodamine compound C was obtained in a yield of 87.1%.

(Example 1, Comparative Example 1, Comparative Example 2)
Rhodamine compound B, rhodamine compound C, comparative compound 1 (rhodamine B), comparative compound 2 (cyanine compound) 7 mg each, polymethyl methacrylate (PMMA) 1 g of chlorobenzene 2.2 g, toluene 0.87 g, acetic acid A coating solution was prepared by dissolving in a mixed solvent of 0.90 g of ethyl and 0.79 g of acetone. This coating solution was applied to a 100 micron thick polyethylene terephthalate (PET) film with a bar coater # 3 and dried at 90 ° C. for 3 minutes. After measuring the transmittance of the obtained test piece, the test piece was continuously irradiated for 144 hours using a light source of 20000 lux, and the intensity of the minimum transmittance between wavelengths 545 to 555 nm was measured again. On the way, the measurement was performed even for 48 hours. Table 1 summarizes the evaluation results of the relative values for each dye, with the intensity of the minimum transmittance of 545 to 555 nm before continuous irradiation being 100.

  As can be seen from Table 1, Examples 1 and 2 using the rhodamine compounds B and C of the present invention showed durability equal to or higher than that of Comparative Example 1 using Rhodamine B in the initial stage. Also showed excellent durability. It is clear that the durability higher than that of rhodamine B persists with time. This result shows that the rhodamine compound of the present invention is effective in realizing excellent durability and suppressing the photodecomposition of the dye.

Claims (1)

A rhodamine compound represented by the following general formula (1).

(Wherein R1 to R2 are each independently unsubstituted or methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, pentyl, An aryl group having 6 to 24 nuclear carbon atoms having a substituent selected from a hexyl group and halogen, wherein R3 is a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, sec- butyl, t- butyl group, a pentyl group, a hexyl group, or a halogen, X ^- represents a counter ion).