A near-infrared light absorber, a composition containing the same, and a filter.

Abstract

This invention discloses a near-infrared light absorber, a composition containing the same, and a filter. The near-infrared light absorber has the structure shown in formula (I): (I); wherein: R1 is independently selected from H, C1-C8 alkyl; R2 is independently selected from H, C1-C6 alkyl; R3 is independently selected from H, C1-C4 alkyl; R4 is independently selected from the following groups: wherein R5 is selected from C1-C12 straight-chain or branched alkyl, phenyl, or C1-C4 alkyl-substituted phenyl; n is 1, 2, 3, or 4. It has a larger maximum infrared absorption wavelength λmax and IR T50%, which can improve the imaging color of visible light filters.

Description

Technical Field

[0001] The present invention specifically relates to a near-infrared light absorber, a composition containing the absorber, and a filter. Background Technology

[0002] Visible light filters are optical devices used to select visible light. They absorb infrared light (including near-infrared light) and ultraviolet light, blocking them from passing through, thus allowing only visible light to pass. Typically, a coating that absorbs infrared and ultraviolet light is applied to the filter's substrate (plastic or glass) to achieve this absorption.

[0003] Infrared light absorbers, such as near-infrared light absorbers, need to maximize the absorption of near-infrared light while ensuring sufficient transmission of visible light. However, the wavelength of near-infrared light is not much different from that of visible light, making it difficult to achieve the aforementioned requirements.

[0004] Patent WO2014088063A1 discloses compound A1 with the following structural formula. It was used as a near-infrared absorbing pigment in near-infrared cutoff filters. However, the maximum absorption wavelength λmax of this compound is 704.7 nm (tested in toluene), which is still insufficient to meet the transmittance requirements of the filter in the visible light region.

[0005] While ensuring sufficient transmission of visible light, it is essential to increase the maximum absorption wavelength λmax of the near-infrared absorber and the wavelength corresponding to 50% infrared spectral transmittance (IR T50%). This can improve the color deviation phenomenon of the filter and make the image color of the filter closer to the true color. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a near-infrared light absorber that addresses the shortcomings and deficiencies of the prior art. This absorber has a larger maximum infrared absorption wavelength λmax and a wavelength IRT50% corresponding to 50% infrared spectral transmittance. When applied to a visible light filter, it can improve its imaging color.

[0007] To solve the above technical problems, the present invention adopts the following technical solution:

[0008] A near-infrared light absorber having the structure shown in formula (I), ;

[0009] in:

[0010] R1 is independently selected from H and C1-C8 alkyl groups;

[0011] R2 is independently selected from H and C1-C6 alkyl groups;

[0012] R3 is independently selected from H and C1-C4 alkyl groups;

[0013] R4 is independently selected from the following groups: R5 is selected from C1-C12 straight-chain or branched alkyl, phenyl, and C1-C4 alkyl-substituted phenyl groups;

[0014] n is 1, 2, 3 or 4.

[0015] In the prior art, near-infrared light absorbers are usually ononium salt absorbers, and compound A1 has been reported in the prior art. While this compound can be used as a near-infrared light absorber, its maximum absorption wavelength λmax is 704.7 nm (tested in toluene), and the corresponding wavelength (IR T50%) at 50% infrared transmittance is relatively small, failing to meet the high requirements of visible light filters. Through long-term research, the inventors of this application discovered that introducing a new cyclic structure onto the five-membered nitrogen-containing heterocycle of the aforementioned compound A1 can increase the electron-donating ability at this point, thereby increasing the conjugation of the entire compound molecule. This results in an increase in the maximum absorption wavelength of the compound's absorption spectrum (i.e., a redshift) without affecting the compound's transmittance in the visible light region. When used as a near-infrared light absorber, its near-infrared light absorption performance is improved, which is highly advantageous when applied to visible light filters, improving their imaging color.

[0016] In some embodiments, R1 is independently a C1-C6 alkyl group.

[0017] In some implementations, R1 is butyl.

[0018] In some embodiments, R2 is independently selected from H and C1-C4 alkyl groups.

[0019] In some embodiments, R2 is a methyl group.

[0020] In some implementations, R3 is H.

[0021] In some implementations, R4 is independently... And R5 is independently selected from C3-C8 straight-chain or branched alkyl, phenyl, or methyl-substituted phenyl groups; or, R4 is independently selected from... And R5 is independently selected from phenyl or methyl-substituted phenyl; or, R4 is independently selected from phenyl or methyl-substituted phenyl. And R5 is independently selected from a C6-C10 straight-chain alkyl group; or, R4 is independently selected from a C6-C10 straight-chain alkyl group. Furthermore, R5 is independently selected from C4-C8 straight-chain or branched alkyl groups.

[0022] In some implementations, n is 1 or 2.

[0023] In some embodiments, the two R1 structures are identical, the two R2 structures are identical, the two R3 structures are identical, and the two R4 structures are identical. That is, the near-infrared light absorber with the structure shown in formula (I) has a symmetrical structure.

[0024] In some embodiments, the near-infrared light absorber is selected from compounds with the following structures:

[0025]

[0026] .

[0027] The present invention also provides a near-infrared light absorbing composition comprising the aforementioned near-infrared light absorber. The aforementioned near-infrared light absorber functions to absorb near-infrared light in the composition and is the main active component responsible for the composition's absorption performance.

[0028] This invention does not limit other components in the near-infrared light absorption composition. Commonly used components in near-infrared light absorption compositions in the art can be added to the composition, as long as they do not substantially affect the near-infrared light absorption performance of the composition. For example, the composition typically uses matrix components such as resins, and other commonly used additives can also be added.

[0029] In some embodiments, the near-infrared light absorbing composition further includes a resin selected from acrylic resins, epoxy resins, mercaptoethanol resins, polycarbonate resins, polyether resins, polyarylate resins, polysulfone resins, polyethersulfone resins, poly(p-phenylene) resins, polyarylene ether phosphooxy resins, polyimide resins, polyamide-imide resins, polyolefin resins, cycloolefin resins, and polyester resins.

[0030] Furthermore, the near-infrared light absorbing composition contains 0.1%-2% by mass of the aforementioned near-infrared light absorber.

[0031] The present invention also provides the application of the aforementioned near-infrared light absorber or near-infrared light absorbing composition in visible light filters.

[0032] Furthermore, the aforementioned near-infrared light absorber or near-infrared light absorbing composition is used in the near-infrared absorbing layer of a visible light filter.

[0033] The present invention also provides a visible light filter, comprising a substrate and a near-infrared light absorbing layer, wherein the near-infrared light absorbing layer contains the aforementioned near-infrared light absorber or near-infrared light absorbing composition.

[0034] Furthermore, the visible light filter also includes a first multilayer film structure disposed on the back side of the substrate, the first multilayer film structure containing multiple films with different refractive indices. This first multilayer film structure typically contains multiple films with alternating high and low refractive indices stacked together. This multilayer film structure can absorb and block infrared light, thus shielding the back side of the substrate from infrared light as well.

[0035] In some embodiments, the material of each layer in the first multilayer film structure is selected from one or more combinations of TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, Si3N4, Ta2O5, ZnS, ZnSe, ZrO2, and Na3AlF6.

[0036] Furthermore, the visible light filter also includes a second multilayer film structure disposed on the ultraviolet light absorption layer, the second multilayer film structure being an anti-reflection layer.

[0037] In some embodiments, the material of each layer in the second multilayer film structure is selected from one or more combinations of TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, Si3N4, Ta2O5, ZnS, ZnSe, ZrO2, and Na3AlF6.

[0038] Due to the implementation of the above technical solutions, the present invention has the following advantages compared with the prior art:

[0039] This invention introduces a new cyclic structure into the five-membered nitrogen-containing heterocycle of existing oniumate-based near-infrared light absorbers. This increases the electron-donating ability at this point, thereby increasing the conjugation of the entire compound molecule. Consequently, it achieves an increase in the maximum absorption wavelength of the compound's absorption spectrum (i.e., a redshift) without affecting the compound's transmittance in the visible light region. When used as a near-infrared light absorber, its near-infrared absorption performance is improved, which is highly advantageous when applied to visible light filters, as it can improve their imaging color.

[0040] Compared with existing compounds, the near-infrared light absorber of the present invention can increase the maximum absorption wavelength of the absorption spectrum by 2-3 nm, exhibiting a significant redshift phenomenon, while the transmittance performance in the visible light region remains unchanged. Attached Figure Description

[0041] Figure 1 The NMR spectrum of target compound B1 in Example 1 is shown.

[0042] Figure 2The NMR spectrum of compound B2, the target compound in Example 2.

[0043] Figure 3 The NMR spectrum of target compound B3 in Example 3 is shown.

[0044] Figure 4 The NMR spectrum of compound B4, the target compound in Example 4.

[0045] Figure 5 The NMR spectrum of target compound B5 in Example 5 is shown.

[0046] Figure 6 The NMR spectrum of target compound B6 in Example 6 is shown.

[0047] Figure 7 The NMR spectrum of target compound B7 in Example 7 is shown.

[0048] Figure 8 The NMR spectrum of compound B8, the target compound in Example 8.

[0049] Figure 9 The NMR spectrum of target compound B9 in Example 9 is shown.

[0050] Figure 10 This is a comparison of the absorption spectra of target compounds B1, B9, and control compound A1.

[0051] Figure 11 This is a comparison chart of the transmittance curves of target compound B1 and control compound A1 on white glass. Detailed Implementation

[0052] definition

[0053] In the compounds described in this invention, when any variable (e.g., R1, R2, etc.) appears more than once in any component, the definition of each occurrence is independent of the definitions of other occurrences. Similarly, combinations of substituents and variables are permitted, provided such combinations stabilize the compound. The definition of any substituent or variable at a specific position in a molecule is independent of other positions in the molecule. It is readily understood that those skilled in the art can select the substituents or substitution forms of the compounds of this invention using existing techniques and the methods described herein to provide chemically stable and readily synthesized compounds.

[0054] As used in this article, "alkyl" refers to saturated aliphatic hydrocarbon groups, including branched and straight-chain groups with a specific number of carbon atoms. For example, the definition of "C1-6" in "C1-6 alkyl" includes groups with 1, 2, 3, 4, 5, or 6 carbon atoms arranged in a straight or branched manner.

[0055] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of protection of the present invention.

[0056] The technical features of the embodiments described below can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the embodiments below are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0057] The following embodiments are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this invention should be determined by the appended claims. Example 1:

[0058] The target compound B1 was synthesized using the following reaction route:

[0059]

[0060]

[0061] The specific synthesis steps are as follows:

[0062] 1) Add 25.0 g of methylcyclohexanone, 24.0 g of phenylhydrazine and 150 mL of acetic acid to a 250 mL reaction flask. After reflux for 24 hours, extract the reaction system with ethyl acetate, separate the organic phase, and concentrate under reduced pressure to obtain liquid compound 1 with a yield of 99%.

[0063] 2) In a 250 mL reaction flask, 20.0 g of compound 1, 80 mL of ethyl acetate and 29.6 g of bromobutane were added and reacted at room temperature for 24 hours. After filtration, solid compound 2 was obtained with a yield of 96%.

[0064] 3) Add 25.0g of compound 2 and 125mL of methanol to a 500mL reaction flask, cool to 5°C, then slowly add 3.9g of sodium borohydride to the reaction flask, react at 0-5°C for 2 hours, then add saturated ammonium chloride aqueous solution to end the reaction, extract the reaction system with ethyl acetate, separate the organic phase, and concentrate under reduced pressure to obtain liquid compound 3 with a yield of 95%.

[0065] 4) Add 72g of concentrated sulfuric acid and 24.0g of compound 3 to a 250mL reaction flask, cool to 5°C, slowly add 6.5g of concentrated nitric acid dropwise to the reaction flask, react at 0-5°C for 2 hours, add 120mL of water to stop the reaction, extract with ethyl acetate, concentrate under reduced pressure to obtain liquid compound 4, with a yield of 98%.

[0066] 5) In a 200 mL high-pressure reactor, 14.0 g of compound 4, 150 mL of toluene and 0.7 g of Pd / C catalyst were added, and 5 kg of hydrogen was introduced to pressurize the reactor. The reactor was then reacted at 50°C for 24 hours. After the reaction was completed, the active Pd / C catalyst was removed by diatomaceous earth filtration to obtain a liquid. After vacuum concentration, liquid compound 5 was obtained with a yield of 90%.

[0067] 6) In a 100 mL reaction flask, add 50 mL of dichloromethane and 11.3 g of compound 5, cool to 5°C, slowly add 4.6 g of isobutyryl chloride dropwise into the reaction flask, react at 0-5°C for 2 hours, then add 50 mL of water to end the reaction, extract, collect the organic layer, concentrate under reduced pressure to obtain liquid compound 6, with a yield of 100%.

[0068] 7) In a 250 mL reaction flask, add 100 mL of toluene, 14.3 g of compound 6, and 2.0 g of compound 6. The mixture was reacted with 10.0 g butanol, heated to 125°C, and subjected to a water separator reaction for 24 hours to remove water. After cooling to room temperature and filtration, solid compound II was obtained in 65% yield.

[0069] The NMR spectrum of target compound B1 is as follows: Figure 1 As shown.

[0070] Examples 2-8:

[0071] Using the same reaction route as in Example 1, but replacing isobutyryl chloride in step 6) with R4-CO-Cl (R4-acyl chloride) of other structures, compounds B2-B8 with similar structures to compound B1 were obtained. The structures of R4 and compound B2-B8 are shown below.

[0072] Example 2: R4 is Compound B2 is

[0073] ;

[0074] Example 3: R4 is Compound B3 is

[0075] ;

[0076] Example 4: R4 is Compound B4 is

[0077] ;

[0078] Example 5: R4 is Compound B5 is

[0079] ;

[0080] Example 6: R4 is Compound B6 is

[0081] ;

[0082] Example 7: R4 is Compound B7 is

[0083] ;

[0084] Example 8: R4 is Compound B8 is

[0085] .

[0086] The NMR spectra of compounds B2-B8 are as follows: Figure 2-8 As shown.

[0087] Example 9:

[0088] The same reaction route as in Example 1 was used, except that the starting material was replaced with (2-methylcyclohexanone) instead of methylcyclohexanone. The target compound B9 was finally obtained, with the following structural formula:

[0089] Its NMR spectrum is as follows: Figure 9 As shown.

[0090] Comparative Example 1:

[0091] Comparative compound A1 is provided:

[0092]

[0093] The specific synthetic route and steps are basically the same as in Example 1, the only difference being that compound 1 is replaced with... And use it directly as a starting material.

[0094] Comparative Examples 2-8:

[0095] Using the same reaction route as Comparative Example 1, but replacing isobutyryl chloride in step 6) with R4-CO-Cl (R4-acyl chloride) of other structures, compounds A2-A8 with similar structures to comparative compound A1 were obtained. The structures of R4 and compound A2-A8 are shown below.

[0096] Comparative Example 2: R4 is Compound A2 is

[0097] ;

[0098] Comparative Example 3: R4 is Compound A3 is

[0099] ;

[0100] Comparative Example 4: R4 is Compound A4 is

[0101] ;

[0102] Comparative Example 5: R4 is Compound A5 is

[0103] ;

[0104] Comparative Example 6: R4 is Compound A6 is

[0105] ;

[0106] Comparative Example 7: R4 is Compound A7 is

[0107] ;

[0108] Comparative Example 8: R4 is Compound A8 is

[0109] .

[0110] Compound B1 from Example 1, compound B9 from Example 9, and compound A1 from Comparative Example 1 were dissolved in toluene, each at a mass concentration of 3 ppm. The absorption spectra of the three compounds were measured, and the results are as follows: Figure 10 As shown in the figure, the orange line represents compound B1, the green line represents compound B9, and the blue line represents compound A1. It can be seen that compound B1 exhibits a redshift relative to compound A1, while compound B9 exhibits a larger redshift relative to A1. The maximum absorption wavelength λmax of the absorption spectra of other examples and comparative compounds was tested using the same method, and the results are shown in Table 1 below.

[0111]

[0112] As shown in Table 1 above, the target compounds B1-B8 exhibit a red shift of approximately 2-3 nm in their maximum absorption wavelength λmax compared to the comparative compounds A1-A8. This indicates that the introduction of a ring structure into the near-infrared pigment molecule structure in this application can significantly increase the maximum absorption wavelength λmax of its absorption spectrum, which is highly advantageous for applications in visible light filters.

[0113] Compound B1 from Example 1 and Compound A1 from Comparative Example 1 were mixed with a toluene solution of acrylic resin (acrylic resin concentration was 10% by mass) to obtain a coating solution. The mass percentage concentrations of both compounds B1 and A1 in the coating solution were 0.45%. The coating solution was applied to white glass with a coating thickness of 1 μm. The transmittance of the entire sample in the visible and infrared regions was then tested. The results are as follows: Figure 11 As shown, the blue line represents compound B1 (with an IR T50% of 679.91 nm and a minimum transmittance wavelength of 712 nm), and the yellow line represents compound A1 (with an IR T50% of 674.89 nm and a minimum transmittance wavelength of 708 nm). It is evident that the target compound B1 exhibits a significant red shift compared to the comparison compound A1. However, in the visible light band, there is no significant difference in transmittance between the two compounds. This means that the compounds in this application can increase the maximum absorption wavelength in the near-infrared region without affecting visible light transmittance.

[0114] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A visible light filter, comprising a substrate and a near-infrared light absorbing layer, characterized in that: The near-infrared light absorbing layer is composed of a resin and a near-infrared light absorber; the near-infrared light absorber is a compound having the structure shown in formula (I): ； in: R1 is butyl; R2 are all methyl groups; R3 are all H; R4 is selected from the following groups: R5 is selected from C1-C12 straight-chain or branched alkyl, phenyl, or C1-C4 alkyl-substituted phenyl groups, and the two R4 groups have the same structure. n is 1 or 2.

2. The visible light filter according to claim 1, characterized in that: R4 independently for And R5 is independently selected from C3-C8 straight-chain or branched alkyl, phenyl, or methyl-substituted phenyl groups; or, R4 is independently selected from... And R5 is independently selected from phenyl or methyl-substituted phenyl; or, R4 is independently selected from phenyl or methyl-substituted phenyl. And R5 is independently selected from a C6-C10 straight-chain alkyl group; or, R4 is independently selected from a C6-C10 straight-chain alkyl group. Furthermore, R5 is independently selected from C4-C8 straight-chain or branched alkyl groups.

3. The visible light filter according to claim 1, characterized in that: The near-infrared light absorber is selected from compounds with the following structures: ； ； 。 4. The visible light filter according to any one of claims 1-3, characterized in that: The resin is selected from acrylic resin, epoxy resin, mercaptoethanol resin, polycarbonate resin, polyether resin, polyarylate resin, polysulfone resin, polyethersulfone resin, poly(p-phenylene) resin, polyarylene ether phosphooxy resin, polyimide resin, polyamide-imide resin, polyolefin resin, cycloolefin resin, and polyester resin.

5. The visible light filter according to any one of claims 1-3, characterized in that: The near-infrared light absorbing layer contains 0.1%-2% of the near-infrared light absorber by mass.

6. The visible light filter according to any one of claims 1-3, characterized in that: The visible light filter further includes a first multilayer film structure disposed on the back side of the substrate, the first multilayer film structure containing multilayer films with different refractive indices.

7. The visible light filter according to claim 6, characterized in that: The material of each layer in the first multilayer film structure is selected from one or more combinations of TiO2, SiO2, Y2O3, MgF2, Al2O3, Nb2O5, AlF3, Bi2O3, Gd2O3, LaF3, PbTe, Sb2O3, Si3N4, Ta2O5, ZnS, ZnSe, ZrO2 and Na3AlF6.

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