Naphthalimide benzoxacyclo yellow dye, ink and electrowetting display device

Abstract

The invention relates to the technical field of dyes, and particularly discloses a naphthalimide benzooxygen heterocyclic yellow dye, ink and an electrowetting display device. The structural formula of the naphthalimide benzooxygen heterocyclic yellow dye is shown in the specification, wherein R1, R2 and R3 are respectively and independently selected from any one of alkyl, alkoxy, alkyl phenyl, alkoxy phenyl and thienyl. A dye main body obtained after coupling of naphthalimide and phenol mainly absorbs blue light of 400-480 nm, the substance is yellow, the main body structure has a large conjugate plane, is immiscible in polar liquid and has a good molar absorption coefficient, the solubility is improved by adding long-chain branched alkyl in the main body structure, and the dye has a good color rendering effect. The prepared dye can be dissolved in an organic solvent to prepare printing ink suitable for electrowetting display, and after the printing ink is applied to an electrowetting display device, the electrowetting display device has good aperture opening ratio, short switch response time, good electrical stability and good optical stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dyes, in particular to a naphthalimide benzoxadiazole yellow dye, an ink and an electrowetting display device. BACKGROUND

[0002] Electrofluide display (EFD) is a display prototype based on the principle of electrofluide display, which was first developed by Philips Company in the Netherlands in 2003. The display principle is to control the surface properties of the hydrophobic layer by changing the voltage, and to change the contact angle of the ink layer on the hydrophobic layer. When no voltage is applied, the ink wets the insulating layer uniformly, forming a colored pixel point; when voltage is applied, the electric field changes the surface properties of the hydrophobic layer, causing the interfacial tension between the ink-polar liquid-hydrophobic layer to change, and the ink is compressed, forming a transparent or substrate color pixel point, thereby obtaining a display image effect.

[0003] The pixel structure of a typical direct drive type electrofluide device is composed of two transparent glass substrates, an ITO conductive layer on the inner side of the upper substrate, and the ITO as a common electrode. On the lower substrate, the conductive ITO layer is etched into a driving electrode. Above the driving electrode is an insulating hydrophobic layer, and the hydrophobicity and dielectric properties of the hydrophobic insulating layer material are crucial, as they directly determine the driving voltage of the electrofluide device and the reliability of the device. Above the insulating hydrophobic layer is a pixel grid structure layer, and the pixel grid is filled with non-polar ink liquid, and the polar liquid is filled between the upper substrate and the non-polar ink layer. The upper and lower substrates are assembled together with a glue frame. In order to realize color electrofluide display, the Dutch Liquvista Company proposed two possible structure models: single-layer or multi-layer structure. Single-layer electrofluide color display uses black ink in combination with color filters, but this method reduces the light utilization efficiency and contrast due to the use of filters; while multi-layer electrofluide color display can be formed by superimposing three primary colors (cyan, magenta, yellow), which has higher light utilization efficiency and high contrast. In multi-layer electrofluide color display, yellow molecules mainly use anthraquinone and azo molecules as the main structure, and the molar absorption coefficient of anthraquinone yellow dye molecules is low, while azo yellow dye molecules are mutually soluble in polar liquid.

[0004] Therefore, it is necessary to provide a naphthalimide benzoxadiazole yellow dye, an ink and an electrowetting display device, which have high solubility and molar absorption coefficient, and are not mutually soluble in polar liquid. SUMMARY

[0005] The present application aims to at least solve one of the technical problems existing in the prior art, and for this purpose, the present application provides a naphthalimide benzoxanthene yellow dye, an ink and an electrowetting display device, the prepared dye and ink have high solubility and molar absorption coefficient, and are not mutually soluble in polar liquids.

[0006] The first aspect of the present application provides a naphthalimide benzoxanthene yellow dye.

[0007] Specifically, the structural formula of the naphthalimide benzoxanthene yellow dye comprises: 、 Or ; Among them, R1, R2, R3 are independently selected from any one of alkyl, alkoxy, alkylphenyl, alkoxyphenyl, thienyl.

[0008] Preferably, the alkyl is selected from any one of propyl, tert-butyl, tert-octyl, 2-ethyl-1-hexyl, 2-butyl-1-octyl, 2-octyl-1-dodecyl.

[0009] Preferably, the naphthalimide benzoxanthene yellow dye comprises 、 、 、 、 、 、 Or .

[0010] The second aspect of the present application provides an ink.

[0011] Specifically, the ink comprises the naphthalimide benzoxanthene yellow dye provided in the first aspect.

[0012] Preferably, the ink comprises a non-polar organic solvent and a naphthalimide benzoxanthene yellow dye.

[0013] Preferably, the ink comprises 5-100 parts by weight of a non-polar organic solvent and 1-30 parts by weight of a naphthalimide benzoxanthene yellow dye.

[0014] Further preferably, the ink comprises 85-95 parts by weight of a non-polar organic solvent and 5-15 parts by weight of a naphthalimide benzoxanthene yellow dye.

[0015] More preferably, the ink comprises 90 parts by weight of a non-polar organic solvent and 10 parts by weight of a naphthalimide benzoxanthene yellow dye.

[0016] Preferably, the non-polar organic solvent comprises at least one of n-decane, n-dodecane, n-tetradecane, n-hexadecane, and fluorine-containing alkanes.

[0017] Preferably, the ink has an absorption wavelength of 400-480 nm.

[0018] Further preferably, the ink has an absorption wavelength of 410-480 nm.

[0019] A third aspect of the present application provides a method for preparing an ink.

[0020] Specifically, the method comprises the following steps: dissolving a naphthalimide benzoxadiazole yellow dye in a solvent to prepare an ink.

[0021] Preferably, the solvent is a non-polar organic solvent.

[0022] A fourth aspect of the present application provides an electrowetting display device.

[0023] Specifically, the electrowetting display device comprises the ink provided in the second aspect.

[0024] Compared with the prior art, the present application has the following advantages: The present application provides a series of naphthalimide benzoxadiazole yellow dyes with a naphthalimide diimide structure. The main body obtained by coupling naphthalimide with phenol mainly absorbs blue light of 400-480 nm, and the substance exhibits yellow color. The main body structure has a large conjugated plane, is not miscible in polar liquids, and has a good molar absorption coefficient. By increasing long branched alkyl groups in the main body structure to increase solubility, the prepared naphthalimide benzoxadiazole yellow dye can be dissolved in an organic solvent to prepare an ink suitable for electrowetting display. After the ink is applied to an electrowetting display device, the electrowetting display device has a good aperture ratio, a short switching response time, good electrical stability, and good optical stability. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 UV-visible absorption spectrum of ink A of Example 5; Figure 2 Molar absorption coefficient result graph of ink A of Example 5; Figure 3 UV-visible absorption spectrum of ink B of Example 6; Figure 4 Molar absorption coefficient result graph of ink B of Example 6; Figure 5 UV-visible absorption spectrum of ink C of Example 7; Figure 6 Molar absorption coefficient result graph of ink C of Example 7; Figure 7 The UV-Vis absorption spectrum of ink D in Example 8 is shown below. Figure 8 The graph shows the molar absorptivity results of ink D in Example 8; Figure 9 These are diagrams of the electrowetting display devices after being powered on in Examples 9 and 10; Figure 10 The image shows the 1H NMR spectrum of dye A. Figure 11 The image shows the 1H NMR spectrum of dye B. Figure 12 The image shows the 1H NMR spectrum of dye C. Figure 13 The image shows the 1H NMR spectrum of dye D. Figure 14 The results are the light aging test results for Examples 9 and 10. Detailed Implementation

[0026] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0027] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0028] Example 1 A naphthalimide benzoxoxoheterocyclic yellow dye, A.

[0029] The reaction formula is as follows: ; 8.0000 g (29.8307 mmol) of 1,4,5,8-naphthalenetetracarboxylic anhydride, 8.3675 g (149.1536 mmol) of potassium hydroxide, and 280 mL of water were added to a 500 mL round-bottom flask. The mixture was heated to 85 °C and stirred for 30 min. 3.82 mL of bromine was titrated using a constant pressure funnel. After the addition was complete, the reaction was continued for 1 h, and then the mixture was cooled. Glacial acetic acid was added to neutralize the pH. The mixture was filtered, washed with water and methanol, and dried under vacuum at 60 °C for 6 h to obtain 13.5105 g (quantitative) of light brown solid 1.

[0030] In a 500 mL round bottom flask, 11.3941 g (32.0086 mmoL) of 1, 14.2872 g (48.0129 mmoL) of 2-n-octyl-1-dodecanamine, and 300 mL of tetrahydrofuran were added, vacuumed, replaced by argon, reacted at 60 °C for 24 h, cooled to room temperature, added into water, filtered by diatomite, washed by methanol, the residue was dissolved by petroleum ether, spin-dried, column chromatography, 14.5101 g of orange-yellow solid 2 was obtained, with a yield of 71.32%.

[0031] The reaction formula is as follows: ; In a 100 mL round bottom flask, 5.0000 g (24.2330 mmoL) of 4-tert-octylphenol, and 30 mL of dichloromethane were added, stirred at room temperature for 30 min, then 4.3130 g (24.2330 mmoL) of N-bromosuccinimide was slowly added in batches, and the reaction was continued for 1 h, spin-dried, column chromatography (eluent: dichloromethane: petroleum ether = 1:2), 6.2724 g (yield 90.75%) of colorless transparent solution 3 was obtained.

[0032] In a 100 mL round bottom flask, 2.0000 g (7.0118 mmoL) of 3, 5.3418 g (21.0357 mmoL) of pinacolatodiboron, 4.1289 g (42.0713 mmoL) of potassium acetate, and 0.5131 g (0.7012 mmoL) of 1,1-bis(diphenylphosphino)ferrocene palladium dichloride were added, vacuumed, replaced by argon, 50 mL of anhydrous 1,4-dioxane was injected by a syringe, reacted overnight at 80 °C, spin-dried, quickly passed through a silica gel column with dichloromethane, 4 was obtained and directly used in the next step.

[0033] ; In a 250 mL round bottom flask, 3.7039 g (5.8281 mmoL) of 2, 2.3300 g (7.0118 mmoL) of 4 (quantitative), 0.6735 g (0.5828 mmoL) of tetrakis(triphenylphosphine)palladium, 20 mL of 2 M potassium carbonate solution, and 80 mL of 1,4-dioxane were added, vacuumed, replaced by argon, reacted overnight at 80 °C, the reaction was stopped, added into water, extracted by dichloromethane, spin-dried, column chromatography (eluent: ethyl acetate: petroleum ether = 1:20), 2.4205 g of orange-yellow solid A (marked as dye A) was obtained, with a yield of 61.1%.

[0034] The characterization data are as follows: 1 H NMR (600 MHz, CDCl3) δ 8.65 (d,J = 7.8 Hz, 1H), 8.58 (d, J = 8.3 Hz, 1H), 8.04 (d, J = 2.2 Hz, 1H), 7.97 (d, J = 7.9 Hz, 1H), 7.57 (dd, J = 8.7, 2.2 Hz, 1H), 7.30 (d, J = 8.7 Hz, 1H), 7.27 (d, J = 8.3 Hz, 1H), 4.12 (d, J = 7.4 Hz, 2H), 2.01 (d, J = 7.9 Hz, 1H), 1.83 (s, 2H), 1.48 (s, 5H), 0.85 (dt, J = 8.9, 7.1 Hz, 6H), 0.77 (s, 8H). The 1H NMR spectrum is as follows: Figure 10 As shown.

[0035] Example 2 A naphthalimide benzoxoxoheterocyclic yellow dye, B.

[0036] ; Add 0.5000 g (0.7352 mmol / L) of A, 1.13 mL (22.0579 mmol / L) of bromine and 20 mL of tetrahydrofuran to a 75 mL pressure flask, react overnight at 66 °C, neutralize with an aqueous solution of sodium bisulfite, extract with petroleum ether, and perform column chromatography (ethyl acetate: petroleum ether = 1:100) to obtain a yellow viscous liquid 5, which can be used directly for the next step.

[0037] In a 100 mL round-bottom flask, add 0.2880 g (1.6175 mmol) of 4-tert-butylphenylboronic acid, 0.0850 g (0.0735 mmol) of tetrakis(triphenylphosphine)palladium, 7 mL of 2M potassium carbonate aqueous solution, and 30 mL of 1,4-dioxane. Evacuate the mixture under vacuum, purge with argon, and react at 80°C overnight. After the reaction is stopped, remove the solvent by rotary evaporation, wash with water and methanol, and perform column chromatography (ethyl acetate: petroleum ether = 1:100). 0.5580 g of a yellow viscous liquid B (denoted as dye B) is obtained, yield: 93.44%.

[0038] The characterization data are: 1 H NMR (600 MHz, CDCl3) δ 8.72 (s, 1H), 8.64 (d,J = 7.8 Hz, 1H), 8.05 (d, J = 2.2 Hz, 1H), 8.00 (d, J = 8.0 Hz, 1H), 7.76 – 7.71 (m, 2H), 7.58 – 7.55(m, 2H), 7.53 (dd, J = 8.7, 2.2 Hz, 1H), 7.27 (s, 1H), 4.14 (d, J = 7.4 Hz, 2H), 2.03 (d, J = 8.3 Hz, 1H), 1.83 (s, 2H), 1.48 (s, 6H), 1.43 (s, 9H), 1.25 (dd, J =29.2, 17.7 Hz, 32H), 0.84 (q, J = 7.2 Hz, 6H), 0.76 (s, 9H). The 1H NMR spectrum is as follows: Figure 11 As shown.

[0039] Example 3 A naphthalimide benzoxoxane heterocyclic yellow dye, C.

[0040] ; In a 100 mL round-bottom flask, add 0.1500 g (0.5599 mmol) of 2,5-dibromo-1,4-benzenediol, 0.7109 g (2.7996 mmol) of pinacol diborate, 0.3297 g (3.3595 mmol) of potassium acetate, and 0.0410 g (0.0560 mmol) of 1,1-bis(diphenylphosphine)diferropalladium dichloride. Evacuate the flask, purge with argon, add 40 mL of anhydrous 1,4-dioxane, and react at 80 °C overnight. After the reaction is stopped, add water, filter with diatomaceous earth, wash with petroleum ether, and evaporate to dryness to obtain 6, which can be used directly in the next step.

[0041] In a 50 mL round-bottom flask, the raw material 6 (prepared in the previous step), 0.7724 g (1.2153 mmol / L) 2, 0.0638 g (0.0552 mmol / L) tetrakis(triphenylphosphine)palladium, 6 mL of 2M potassium carbonate solution, and 24 mL of 1,4-dioxane were added. The mixture was evacuated, purged with argon, and reacted overnight at 100°C. After the reaction was stopped, water was added, and the mixture was extracted with dichloromethane, dried over anhydrous magnesium sulfate, and subjected to column chromatography (ethyl acetate: petroleum ether = 1:0) to obtain 0.0464 g of yellow product C (denoted as dye C), yield: 7.94%.

[0042] Characterization data are as follows: 1 H NMR (600 MHz, CDCl3) δ 8.58 (d, J = 7.3 Hz, 2H), 8.46 (d, J = 8.4 Hz,2H), 8.05 (d, J = 8.4 Hz, 2H), 7.62 (t, J = 7.8 Hz, 2H), 6.72 (d, J = 8.5 Hz, 2H),4.09 (d, J = 7.4 Hz, 4H). The proton nuclear magnetic resonance spectrum is shown in Figure 12

[0043] Example 4 A naphthalimide benzoxazole yellow dye D.

[0044] ; In a 50 mL round-bottom flask, 0.3000 g (0.3045 mmoL) of 1,7-dibromo NDI, 0.2172 g (0.7614 mmoL) of 3 and 0.1263 g (0.9136 mmoL) of potassium carbonate were added, vacuumed, replaced with argon, 15 mL of anhydrous N,N-dimethylformamide was added, and the reaction was carried out at 80°C overnight. The reaction was stopped, added to water, broken with a small amount of dilute acid, extracted with dichloromethane, and column chromatography (ethyl acetate: petroleum ether = 1:20) was performed to obtain 0.3764 g of yellow product 4, with a yield of 88.69%.

[0045] In a 50 mL round-bottom flask, 0.2949 g (0.2115 mmoL) of 4, 0.0144 g (0.0635 mmoL) of palladium acetate and 0.1462 g (1.0580 mmoL) of potassium carbonate were added, vacuumed, replaced with argon, 15 mL of anhydrous N,N-dimethylformamide was added, and the reaction was carried out at 135°C overnight. The reaction was stopped, added to water, filtered with diatomite, washed with methanol, and then dissolved in dichloromethane. Column chromatography (ethyl acetate: petroleum ether = 1:80) was performed to obtain 0.0321 g of yellow product D (denoted as dye D), with a yield of 12.32%.

[0046] Characterization data are as follows: 1 H NMR (600 MHz, CDCl3) δ 9.73 (d, J = 2.0 Hz, 2H), 7.83 – 7.77 (m, 4H),4.39 (d, J ​= 7.3 Hz, 4H), 2.17 (p, J = 6.6 Hz, 2H), 1.94 (s, 4H), 1.43 (s, 6H),0.86 (dt, J = 21.3, 7.0 Hz, 12H), 0.76 (s, 18H). The nuclear magnetic hydrogen spectrum is shown in Figure 13

[0047] Example 5 An ink.

[0048] 10 parts of the naphthalimide benzoxa cyclic yellow dye A synthesized in Example 1 was dissolved in 90 parts of n-decane to prepare ink A. The ultraviolet-visible absorption spectrum is shown in Figure 1 , and the molar absorption coefficient result is shown in Figure 2 .

[0049] Example 6 An ink.

[0050] 10 parts of the naphthalimide benzoxa cyclic yellow dye B synthesized in Example 2 was dissolved in 90 parts of n-decane to prepare ink B. The ultraviolet-visible absorption spectrum is shown in Figure 3 , and the molar absorption coefficient result is shown in Figure 4 .

[0051] Example 7 An ink.

[0052] 10 parts of the naphthalimide benzoxa cyclic yellow dye C synthesized in Example 3 was dissolved in 90 parts of n-decane to prepare ink C. The ultraviolet-visible absorption spectrum is shown in Figure 5 , and the molar absorption coefficient result is shown in Figure 6 .

[0053] Example 8 An ink.

[0054] 10 parts of the naphthalimide benzoxa cyclic yellow dye D synthesized in Example 4 was dissolved in 90 parts of n-decane to prepare ink D. The ultraviolet-visible absorption spectrum is shown in Figure 7 , and the molar absorption coefficient result is shown in Figure 8 .

[0055] Example 9 An electrowetting display device.

[0056] The ink A prepared in Example 5 was filled into the electrowetting display device.

[0057] Example 10 An electrowetting display device. ​

[0058] The ink B prepared in Example 6 was filled into an electrowetting display device.

[0059] Performance detection: 1. Molar absorption coefficient test: The inks of Examples 5-8 were dissolved in petroleum ether, and the optical properties of the inks were tested by a UV-Vis absorption spectrometer. The test results are shown in Table 1.

[0060] Table 1. Ink performance test results

[0061] As can be seen from Table 1, the naphthalimide benzoxanthene main body absorbs blue-violet light at the maximum absorption wavelength, and presents its complementary color yellow. Keeping the main body unchanged, adding a benzene ring and an alkyl chain will not change the maximum absorption wavelength.

[0062] 2. Openness test of ink in electrowetting display device: The openness of an electrowetting display device refers to the maximum value of the proportion of the area of the white substrate exposed after the ink in the pixel grid is displaced under the action of a driving voltage to the entire pixel grid area. The openness is an important indicator of the functionality of a reflective display, and can directly reflect the reflectivity of the display device. By testing this performance, the shrinkage characteristics of the ink and the stability of the shrinkage state under the action of voltage can be evaluated. The electrowetting display devices prepared from Examples 9-10 were selected for openness testing, and the test results are shown in Table 2. Figure 9

[0063] Table 2. Openness test results

[0064] 3. Switching response time test of ink in electrowetting display device: Response time is a key indicator of display performance. It reflects the response speed of the pixel grid to the electrical driving signal, including the opening time from dark state to bright state and the closing time from bright state to dark state. Shorter response time can reduce the trailing and blur of dynamic pictures, providing smooth and clear visual experience, while excessively long response time can cause residual image effect, affecting the display quality of high dynamic scenes such as video playing. The electrowetting display devices prepared from Examples 9 and 10 were selected for switching response time testing, and the test results are shown in Table 3.

[0065] Table 3. Response time test results

[0066] 4. Light aging test of ink in electrowetting display device: ​Optical stability is one of the indicators to measure the performance of a display. The optical stability of a display device under sunlight is simulated by testing the change of the UV-Vis absorption spectrum of the display device after the display device is exposed in a xenon lamp weathering test chamber for a period of time, which reflects the service life of the display device. The test results are shown in Figure 14 .

[0067] The preferred embodiments of the present application are described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and changes without departing from the spirit and scope of the present application. Therefore, any modifications, equivalent replacements, improvements, etc. made by those of ordinary skill in the art based on the concept of the present application and the prior art through logical analysis, reasoning or limited experiments shall be within the scope of protection defined by the claims.

Claims

1. A naphthalimide benzoxoxane heterocyclic yellow dye, characterized in that, The structural formula of the naphthalimide benzoxyl heterocyclic yellow dye includes: , or ; R1, R2, and R3 are each independently selected from any one of alkyl, alkoxy, alkylphenyl, alkoxyphenyl, and thiophene groups.

2. The naphthalimide benzoxoxane heterocyclic yellow dye according to claim 1, characterized in that, The alkyl group is selected from any one of propyl, tert-butyl, tert-octyl, 2-ethyl-1-hexyl, 2-butyl-1-octyl, and 2-octyl-1-dodecyl.

3. The naphthalimide benzoxoxane heterocyclic yellow dye according to claim 1, characterized in that, The structural formula of the naphthalimide benzoxyl heterocyclic yellow dye includes: , , , , , , or .

4. An ink, characterized in that, The ink comprises any one of the naphthalimide benzoxoxoheterocyclic yellow dyes according to claims 1 to 3.

5. The ink according to claim 4, characterized in that, The ink comprises a nonpolar organic solvent and a naphthalimide benzoxoxane heterocyclic yellow dye.

6. The ink according to claim 5, characterized in that, The ink comprises, by weight, 5-100 parts of a nonpolar organic solvent and 1-30 parts of a naphthalimide benzoxoxane heterocyclic yellow dye.

7. The ink according to claim 5, characterized in that, The nonpolar organic solvent includes at least one of n-decane, n-dodecane, n-tetradecane, n-hexadecane, and fluorinated alkanes.

8. The ink according to claim 4, characterized in that, The absorption wavelength of the ink is 400~480 nm.

9. The method for preparing the ink according to any one of claims 4 to 8, characterized in that, Includes the following steps: The ink was prepared by dissolving naphthalimide benzoxoxane heterocyclic yellow dye in a solvent.

10. An electrowetting display device, characterized in that, The electrowetting display device comprises the ink according to any one of claims 4 to 8.

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