A fluorescent coated reflective film, its preparation method and its application

Abstract

This invention discloses a fluorescent coated reflective film, its preparation method, and its application. A tetrazaporphyrin compound with a conjugated macrocyclic structure is added, pre-modified, and then formulated with a functional monomer containing a thiol group, an acrylic monomer, or an oligomer to form a coating slurry. This slurry is then applied to a reflective film substrate and thermo-cured to obtain the fluorescent coated reflective film. The tetrazaporphyrin fluorescent material used in this invention has alkylthio group substituents. The pre-modification treatment and the introduction of vinyl groups allow the fluorescent material to be chemically bonded to the main resin in the coating after thermo-curing polymerization, improving dispersion uniformity and stability, thereby improving the film's light utilization rate and display effect, and enhancing light emission uniformity and color saturation.

Description

Technical Field

[0001] This invention relates to the field of optical reflective film technology, specifically to a fluorescent coated reflective film, its preparation method, and its application. Background Technology

[0002] LCD panels themselves do not emit light; instead, they rely on a backlight module to display images. The backlight module's light source devices mostly use blue light chips to excite yellow phosphors to form white light. The blue light portion of its spectrum is relatively pure, while the green and red light portions do not have obvious peaks. Therefore, the saturation of green and red in the imaging spectrum is relatively low, resulting in color distortion.

[0003] In recent years, quantum dot materials have been widely used to enrich colors and improve color gamut, and they are extensively applied in liquid crystal display products in the form of optical films. Quantum dots can undergo electron transitions to form electron-hole pairs when excited by external energy, and the recombination of these pairs releases photons. Due to the confinement effect of quantum dot materials, their emission bands are very narrow, resulting in distinct peaks for red, green, and blue light, and high color saturation after imaging, which can significantly improve the color rendering and color reproduction capabilities of display devices. However, quantum dot materials are sensitive to temperature, humidity, and oxygen, and are prone to fluorescence quenching and inactivation, exhibiting poor stability. For example, the invention disclosed in publication number CN117930545A discloses a quantum dot reflective film and its preparation method, as well as a backlight module. This method involves coating a resin layer with bubbles, then encapsulating embedded quantum dots in the resin layer to form a base film to improve quantum dot stability, and finally applying a functional coating to the base film to obtain the quantum dot reflective film. This process is complex and difficult to implement. In addition, quantum dots are generally composed of elements IV, II-VI, IV-VI or III-V, which contain heavy metals and are not conducive to environmental compliance.

[0004] Furthermore, tetrazaporphyrin compounds with conjugated systems and electron delocalization properties have been found to be potential materials for improving color gamut and effectively enhancing the luminous performance of displays. However, tetrazaporphyrin compounds have problems such as poor dispersion and poor stability in the field of optical films, especially in film coatings, resulting in poor brightness uniformity and poor light resistance of finished films. Based on this, the present invention is proposed. Summary of the Invention

[0005] This invention discloses a fluorescent coated reflective film, its preparation method, and its application. A tetrazaporphyrin compound with a conjugated macrocyclic structure is added, pre-modified, and then formulated with a functional monomer containing a thiol group, an acrylic monomer, or an oligomer to form a coating slurry. This slurry is then applied to a reflective film substrate and thermocured to obtain the fluorescent coated reflective film. The tetrazaporphyrin compound has a wide absorption wavelength range, which can filter stray light and also exhibits fluorescent properties, thereby improving the color saturation of the display.

[0006] This invention is achieved through the following technical solution:

[0007] On one hand, a fluorescent coated reflective film includes a reflective film substrate and a coating, wherein the coating is obtained by applying a coating liquid slurry to the surface of the reflective film substrate and then thermally curing it.

[0008] The reflective film substrate includes at least one of PET film and polypropylene film;

[0009] Preferably, the reflective film substrate is a PET reflective film with a reflectivity > 95%.

[0010] The coating thickness is 20–50 μm.

[0011] The coating liquid comprises the following components: pre-modified fluorescent material, resin, pressure-resistant particles, thermosetting agent, additives, and organic solvent.

[0012] Furthermore, the pre-modified fluorescent material is a tetrazaporphyrin compound pre-modified with a compound containing an anhydride group;

[0013] Preferably, the compound with an anhydride group is methacrylic anhydride or acrylic anhydride.

[0014] Furthermore, the general structural formula of the tetrazaporphyrin compound (TAP(M)) is shown in formula (1), formula (1): Wherein, M is a metal ion; preferably, M is Cu. 2+ or Zn 2+ or Co 2+ or Fe 2+ or Mg 2+ ;

[0015] Among them, at least one of R1 to R8 is a substituent of alkylthio, including methylthio or butylthio, and the rest are each independently substituents of hydrogen atom, halogen element, branched or cyclic aliphatic hydrocarbon group with 3 to 10 carbon atoms, aromatic hydrocarbon group, hydroxyl group, sulfonic acid group, amino group, aminoalkyl group or cyano group.

[0016] Furthermore, the pre-modification reaction mechanism is that the alkylthio group, such as methylthio or butylthio, on the structure of the tetrazaporphyrin compound has a sulfur atom that acts as a nucleophile to attack the highly active carbonyl carbon in the acid anhydride, resulting in a nucleophilic substitution reaction to generate a porphyrin derivative containing a sulfur ester bond and release acrylic acid as a byproduct.

[0017] Taking acrylic anhydride as an example, the corresponding reaction equation can be expressed as: TAP+ n C6H6O3→TAP-(CO-CH=CH2) n + n C3H4O2.

[0018] As a preferred method, polar aprotic solvents (such as DMF and DMSO) are used during the reaction to improve the solubility of the reactants and promote nucleophilic attack. At the same time, a base (such as triethylamine) is added as a catalyst to neutralize the acrylic acid generated in the reaction and avoid protonation that inhibits the reaction. The reaction temperature is usually controlled between 60 and 100°C to avoid side reactions (such as porphyrin ring degradation) caused by excessively high temperatures.

[0019] Furthermore, the tetrazaporphyrin compound can be obtained by condensing a precursor with a metal ion (such as magnesium ion or sodium ion) in an organic solvent (such as n-propanol, n-butanol, trichlorobenzene, or quinoline) using a metal ion (such as magnesium ion or sodium ion) as a template; subsequently, the metal ion is removed by acidification (such as trifluoroacetic acid or sulfuric acid) to obtain a free ligand tetrazaporphyrin; the free ligand tetrazaporphyrin can then react with different metal salts to obtain various metal tetrazaporphyrin complexes.

[0020] Furthermore, the precursor may be maleic anhydride and its derivatives, including alkylthiomaleic anhydride;

[0021] Furthermore, the precursor is one or more of maleic anionyl, dimethylthiomaleic anionyl, and di-n-butylthiomaleic anionyl;

[0022] Preferably, the precursor is dimethylthiomaleic nitrile, di-n-butylthiomaleic nitrile, or a mixture of dimethylthiomaleic nitrile and / or di-n-butylthiomaleic nitrile and maleic nitrile.

[0023] In some embodiments of the present invention, the tetrazaporphyrin compound is an octamethylthiotetrazaporphyrin compound with the structural formula shown in formula (2): .

[0024] The resin is a monomer and / or oligomer;

[0025] Preferably, the resin is a mixture of at least one functional monomer containing a thiol group and at least one acrylic monomer or oligomer.

[0026] Furthermore, the amount of the functional monomer containing thiol and the acrylic monomer or oligomer is 1:2 to 6 by mass.

[0027] Preferably, the functional monomer containing a thiol group specifically includes one or more of the following: trimethylolpropane tris(3-mercaptopropionic acid) ester (TMPMP), pentaerythritol tetra(3-mercaptopropionic acid) ester (PETMP), ethylene glycol di(3-mercaptopropionic acid) ester (GDMP), 1,4-butanediol di(3-mercaptopropionic acid) ester (BDMP), mercaptoacrylate, mercaptomethacrylate, and 2-mercaptothiophene.

[0028] The acrylic monomers refer to esters containing an acrylic acid structure or their homologues, containing one or more acrylate reactive functional groups, such as monofunctional monomers, difunctional monomers, trifunctional monomers, and highly functional monomers, and may also include the above-mentioned acrylic acid derivatives.

[0029] Preferably, the acrylic monomers specifically include one or more of isobornyl acrylate (IBOA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), 1,6-hexanediol diacrylate (HDDA), propoxyglycerol triacrylate (GPTA), and tripropylene glycol diacrylate (TPGDA).

[0030] Further, the oligomer is an acrylate oligomer, which is a polymer composed of a small number of repeating units. The acrylate oligomer includes one or more of the following: aliphatic polyurethane acrylate, polyurethane acrylate, aromatic polyurethane acrylate, epoxy acrylate, epoxidized soybean oil acrylate, modified epoxy acrylate, epoxy methacrylate, aliphatic silicone acrylate, silicone polyurethane acrylate, polybutadiene dimethacrylate, polybutadiene diacrylate, polyester acrylate, acrylate polyester, and chlorinated polyester acrylate.

[0031] The compression-resistant particles include one or more of polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polybutyl methacrylate (PBMA), polyamide (PA), and polyurethane (PU);

[0032] Preferably, the particle size of the compressive strength particles is 1 μm to 60 μm;

[0033] Preferably, the particle size of the pressure-resistant particles is 3 μm to 50 μm.

[0034] The thermosetting agent includes isocyanate curing agents, specifically aromatic isocyanate curing agents, aliphatic isocyanate curing agents, alicyclic isocyanate curing agents, etc., and more specifically, one or more of TDI trimer, hexamethylene diisocyanate, isophorone diisocyanate, and IPDI trimer.

[0035] In this invention, the auxiliary agent is any one or a mixture of two of the following: antistatic agent and dispersant;

[0036] As a preferred option, when adding chemical additives, the appropriate type of additive can be selected according to actual needs and performance requirements. For example, an antistatic agent can be added to reduce or eliminate static electricity accumulation; a dispersant can be selected to promote the uniform dispersion of each component; and the performance of the coating liquid can be further optimized through the reasonable addition of additives.

[0037] For example, the antistatic agent includes at least one of fatty alcohol phosphate salt antistatic agents, alkyl phosphate salt antistatic agents, and fatty alcohol polyoxyethylene ether antistatic agents;

[0038] The dispersant includes at least one of polyurethane dispersants, polyacrylate dispersants, modified polyacrylate dispersants, and polyester dispersants.

[0039] Specifically, the specific components of the coating liquid, by mass parts, are as follows:

[0040] 2-8 parts of pre-modified fluorescent material

[0041] 60-80 parts of resin

[0042] 6-10 parts of compressive strength particles

[0043] 1-3 parts of thermosetting agent

[0044] 3-5 parts of auxiliary agent

[0045] The solid content of the organic solvent coating slurry is maintained at 30-60 wt% to meet the required amount.

[0046] The organic solvent includes a first solvent and a second solvent;

[0047] The first solvent includes at least one of carbon tetrachloride or tetrahydrofuran, used to disperse the pre-modified tetrazaporphyrin compound fluorescent material and the pressure-resistant particles;

[0048] The second solvent includes at least one of N,N-dimethylformamide, ethyl acetate, and butyl acetate.

[0049] On the other hand, a method for preparing a fluorescent coated reflective film includes the preparation of a pre-modified tetrazaporphyrin compound fluorescent material and the preparation of the fluorescent coated reflective film:

[0050] Step 1: Preparation of pre-modified tetrazaporphyrin compound fluorescent materials

[0051] (1) Preparation of tetrazaporphyrin compounds

[0052] Synthesis of TAP(Mg): Magnesium powder, iodine, and n-butanol were sequentially added to a three-necked flask under nitrogen atmosphere, stirred, and heated under reflux for 6–10 h until the magnesium powder was completely eliminated, yielding a n-butanol solution of magnesium n-butoxide. The reaction system was cooled to room temperature, and a n-butanol suspension of the precursor was added under inert gas (N2) protection. The mixture was heated under reflux for 20 h with vigorous stirring, filtered while hot, and the filtrate was evaporated under reduced pressure. TAP(Mg) was then recrystallized from acetone.

[0053] Furthermore, the synthesis of free ligand TAP can be achieved by adding TAP (Mg) to a strong acid (trifluoroacetic acid or sulfuric acid), stirring continuously for 12 h in the dark, and after the reaction is complete, pouring the reaction solution into ice water, extracting with dichloromethane, washing the organic phase with saturated brine, drying with anhydrous sodium sulfate, filtering, and evaporating the solvent to obtain magnesium-free free ligand TAP.

[0054] Alternatively, the free ligand tetrazaporphyrin (i.e., uncoordinated tetrazaporphyrin TAP) and the metal acetate or halide (such as chloride or bromide) are stirred and heated under nitrogen atmosphere in chlorobenzene, DMF (N,N-dimethylformamide) or a mixed solvent of chlorobenzene and DMF, filtered while hot, the filtrate is evaporated under reduced pressure, the solid is washed with 10% hydrochloric acid and pure water, and dried to obtain metal-coordinated tetrazaporphyrin (TAP(M)).

[0055] The precursor can be maleic anhydride and its derivatives, such as one or more of maleic anhydride, dimethylthiomaleic anhydride, and di-n-butylthiomaleic anhydride.

[0056] (2) Preparation of pre-modified tetrazaporphyrin compounds

[0057] The purpose of pre-modification is to introduce vinyl groups into the structure of the tetrazaporphyrin compound, providing a basis for subsequent thermosetting and chemical bonding with the coating substrate resin.

[0058] The pre-modification can be achieved by mixing a tetrazaporphyrin compound with a compound containing an anhydride group in a polar aprotic solvent (such as DMF or DMSO), adding a catalyst under nitrogen protection, and reacting at 50–80°C for 18–36 hours; wherein the ratio of the tetrazaporphyrin compound to the compound containing anhydride group is 1:5–8 by molar weight; finally, the resulting solid is washed and dried to obtain the pre-modified tetrazaporphyrin compound fluorescent material.

[0059] Preferably, the compound with an anhydride group is methacrylic anhydride or acrylic anhydride;

[0060] Preferably, the catalyst is triethylamine, and the amount of catalyst used, by molarity, is catalyst:tetraazaporphyrin compound 1:0.4-0.6.

[0061] In some embodiments of the present invention, triethylamine is selected as the catalyst. To prevent the loss of the tetrazaporphyrin metal coordination ions during the pre-modification process, a pre-modification operation is performed on the free ligand tetrazaporphyrin (i.e., TAP without metal coordination) compound; that is, the free ligand tetrazaporphyrin (i.e., tetrazaporphyrin without metal coordination) is first pre-modified with triethylamine as the catalyst, and then coordinated with the metal ions; the corresponding steps are as follows:

[0062] Free ligand tetrazaporphyrin and a compound with an anhydride group are mixed in a polar aprotic solvent (such as DMF or DMSO), and under nitrogen protection, triethylamine is added as a catalyst, and the reaction is carried out at 50–80 °C for 18–36 hours. The ratio of the free ligand tetrazaporphyrin compound to the compound with an anhydride group is 1:5–8 by molar weight. Finally, the obtained solid is washed and dried to obtain a pre-modified free ligand tetrazaporphyrin fluorescent material, denoted as TAP-MAE.

[0063] Next, metal coordination is performed to obtain pre-modified metal-coordinated tetrazaporphyrin fluorescent materials TAP(M)-MAE, including but not limited to cobalt-coordinated tetrazaporphyrin, denoted as TAP(Co)-MAE; and copper-coordinated tetrazaporphyrin, denoted as TAP(Cu)-MAE.

[0064] Step 2: Preparation of fluorescent coated reflective film

[0065] (1) According to the formula, disperse the TAP(M)-MAE fluorescent material and the pressure-resistant particles prepared in step one into the first solvent, ultrasonically disperse for 1 to 3 hours, and stir evenly to obtain the first suspension;

[0066] The compression-resistant particles include at least one of polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polybutyl methacrylate (PBMA), polyamide (PA), and polyurethane (PU);

[0067] The first solvent includes at least one of carbon tetrachloride and tetrahydrofuran.

[0068] (2) Resin addition: According to the formula, first dissolve the functional monomer containing thiol groups in the second solvent, stir evenly, and then mix with the first suspension obtained in step (1) of step two. Continue stirring, and then add acrylic monomers or oligomers, thermosetting agents, and additives in sequence to obtain the final coating liquid slurry; control the solid content of the coating liquid slurry to be maintained at 30-60 wt%;

[0069] The second solvent includes at least one of N,N-dimethylformamide, ethyl acetate, and butyl acetate;

[0070] The functional monomers containing thiol groups include one or more of the following: trimethylolpropane tris(3-mercaptopropionic acid) ester (TMPMP), pentaerythritol tetra(3-mercaptopropionic acid) ester (PETMP), ethylene glycol di(3-mercaptopropionic acid) ester (GDMP), 1,4-butanediol di(3-mercaptopropionic acid) ester (BDMP), mercaptoacrylate, mercaptomethacrylate, and 2-mercaptothiophene.

[0071] Preferably, the acrylic monomers specifically include one or more of isobornyl acrylate (IBOA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), 1,6-hexanediol diacrylate (HDDA), propoxyglycerol triacrylate (GPTA), and tripropylene glycol diacrylate (TPGDA).

[0072] Further, the oligomer is an acrylate oligomer, which is a polymer composed of a small number of repeating units. The acrylate oligomer includes one or more of the following: aliphatic polyurethane acrylate, polyurethane acrylate, aromatic polyurethane acrylate, epoxy acrylate, epoxidized soybean oil acrylate, modified epoxy acrylate, epoxy methacrylate, aliphatic silicone acrylate, silicone polyurethane acrylate, polybutadiene dimethacrylate, polybutadiene diacrylate, polyester acrylate, acrylate polyester, and chlorinated polyester acrylate.

[0073] (3) The obtained coating liquid is coated on one side of the reflective film substrate and then heat-cured in an oven to obtain a fluorescent coated reflective film;

[0074] The reflective film substrate includes at least one of PET film and polypropylene film;

[0075] The thermosetting temperature is 100-120℃, and the reaction time is 1-3 min, so that the coating is firmly adhered to the substrate surface.

[0076] Thirdly, an application of a fluorescent coated reflective film, wherein the fluorescent coated reflective film can be applied in a display module / display device; the display module includes at least one of an LCD module and a Mini-LED module;

[0077] The display device includes at least one of a television, a mobile phone, a laptop computer, and a vehicle central control screen.

[0078] Compared with the prior art, the present invention has the following beneficial effects:

[0079] (1) The addition of pre-modified tetrazaporphyrin fluorescent material in the reflective film coating can be used in conjunction with the backlight module in the display device to improve the utilization rate of light and the display effect. In particular, it also has fluorescent properties. The fluorescence emission wavelength usually falls in the visible light (such as red light) or near-infrared region, thereby optimizing the color performance and making the picture more vivid and realistic. In addition, it enhances visual comfort: the fluorescent material can absorb a specific range of stray light in the backlight, including yellow and orange light, improve its color purity, and make the backlight module emit brighter and closer to white.

[0080] (2) The tetrazaporphyrin fluorescent material used in this invention has alkylthio groups, such as methylthio or butylthio groups. After pre-modification treatment, the introduction of vinyl groups enables the fluorescent material to be chemically bonded to the main resin in the coating after thermosetting polymerization, thereby further improving its dispersion uniformity and stability. Attached Figure Description

[0081] Figure 1 A schematic diagram of a fluorescent coated reflective film structure;

[0082] Icons: 1—Coating; 2—Reflective film substrate; 3—Pressure-resistant particles; 4—Fluorescent material.

[0083] Figure 2 Schematic diagram of the pre-modification of tetrazaporphyrin fluorescent material and its bonding with the main resin of the coating.

[0084] Figure 3 The cross-section (SEM) of the fluorescent coated reflective film of this invention is 200 μm.

[0085] Figure 4 The cross-section (50 μm) of the fluorescent coated reflective film of this invention is obtained by SEM. Detailed Implementation

[0086] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention.

[0087] Unless otherwise specified, the materials used in this invention are commercially available products, and the methods used are conventional technical means.

[0088] The acquisition of free ligand tetrazaporphyrin compounds (TAP), pre-modified free ligand tetrazaporphyrin compounds (TAP-MAE), and pre-modified metal tetrazaporphyrin compounds (TAP(M)-MAE) is specifically as follows:

[0089] (1) Preparation of TAP(Mg):

[0090] (1-1) Synthesis of 1,2-dimethylthiomaleiconitrile: 2.8 g (15 mmol) of cis-1,2-dicyano-1,2-ethyldithiosodium salt was weighed into a 250 mL round-bottom flask. 100 mL of CH3OH was added under light protection, and the mixture was stirred at room temperature for 1 h until fully dispersed. Then, 2.1 mL of CH3I was added, and the reaction was stopped after stirring for 24 h. The filtrate was collected, concentrated, and then passed through a column chromatography system of CH2Cl2:PE = 3:1. The first pale yellow spot was collected, and the concentrated product was a yellow solid, which was the target product. After vacuum drying for 24 h, the product 1,2-dimethylthiomaleiconitrile was obtained.

[0091] (1-2) Preparation of TAP(Mg) with methylthio group as precursor: 1.0 g magnesium powder, a small amount of iodine and 20 mL n-butanol were successively added into a three-necked flask under nitrogen atmosphere, stirred and heated under reflux for 6-10 h until the magnesium powder was completely removed, and a n-butanol solution of magnesium n-butoxide was obtained; the reaction system was cooled to room temperature, and under inert gas (N2) protection, 3.5 g of 1,2-dimethylthiomaleiconitrile was weighed and dissolved in 40 mL n-butanol solution, and then the solution was added to the above reaction system and heated under reflux for 16-20 h with strong stirring;

[0092] Post-treatment: The reaction solution was filtered while hot, the filtrate was evaporated to dryness under reduced pressure, and the solution was recrystallized from acetone to obtain TAP(Mg).

[0093] Similarly, TAP'(Mg) was prepared using maleic anionyl nitrile as a precursor.

[0094] (2) Obtaining TAP: 2g TAP(Mg) was added to 20mL of trifluoroacetic acid and stirred continuously for 12h in the dark. After the reaction was completed, the reaction solution was poured into ice water and extracted with dichloromethane (2 × 100 mL). The organic phase was washed with saturated brine, dried with anhydrous sodium sulfate, and the solvent was evaporated to obtain the magnesium-free free ligand TAP.

[0095] Similarly, the magnesium-free ligand TAP' was obtained.

[0096] (3) TAP pre-modification treatment: Under nitrogen protection, add TAP (0.1 mmol) and dry DMF (20 mL) to a dry three-necked flask and stir until completely dissolved; bubble the reaction system with nitrogen for 5 minutes to remove oxygen, then add acrylic anhydride (0.5 mmol) dropwise, followed by triethylamine (0.2 mmol) as a base catalyst; seal the reaction and control the reaction temperature at 70℃, and react for 12 hours under magnetic stirring; after the reaction is completed, cool to room temperature, pour the reaction solution into ice water, precipitate solid, filter and collect crude product, wash 3 times with deionized water, and then wash 2 times with anhydrous ethanol to remove unreacted acrylic anhydride and triethylamine, and put the product into a vacuum drying oven and dry at 40℃ for 2 hours to obtain the target product, which is denoted as TAP-MAE.

[0097] Similarly, a pre-modified TAP'-MAE can be obtained.

[0098] (4) Premodified tetrazaporphyrin materials with different metal coordination

[0099] (4-1) Obtaining TAP(Cu)-MAE: Add 25 mL of chlorobenzene to a three-necked flask containing 2.0 g of copper acetate and 0.3 g of TAP-MAE, stir and heat under reflux for 24 hours under a nitrogen atmosphere; after the reaction is completed, filter while hot, and then evaporate the filtrate under reduced pressure. The obtained solid is washed repeatedly with 10% hydrochloric acid, and then washed with water until neutral to remove residual hydrochloric acid. After drying, TAP(Cu)-MAE is obtained.

[0100] (4-2) TAP(Co)-MAE was obtained by coordination treatment with cobalt chloride solution in the same manner as in step (1); at the same time, TAP'-MAE was coordinated with copper acetate solution to obtain TAP'(Cu)-MAE.

[0101] Reflective film substrate: Ningbo Changyang Technology Co., Ltd., reflective film model FDX225.

[0102] Example 1

[0103] This invention provides a fluorescent coated reflective film, the corresponding structural schematic diagram of which is attached. Figure 1 As shown, the image includes a reflective film substrate and a coating; its cross-sectional SEM image is attached. Figure 3 and attached Figure 4 As shown, the coating is obtained by applying a coating liquid slurry to one side of the reflective film substrate and then thermally curing it. The coating contains a pre-modified tetrazaporphyrin fluorescent material. A schematic diagram of the pre-modification of the tetrazaporphyrin fluorescent material and its bonding with the main resin of the coating is attached. Figure 2 As shown; specifically, the preparation steps of the fluorescent coated reflective film are as follows:

[0104] (1) According to the formula, 5 parts of TAP(Cu)-MAE fluorescent material and 10 parts of PET particles are dispersed in carbon tetrachloride solvent, ultrasonically dispersed for 1 to 3 hours, and stirred evenly to obtain the first suspension;

[0105] (2) Resin addition: According to the formula, first dissolve 20 parts of pentaerythritol tetra(3-mercaptopropionic acid) ester (PETMP) monomer in N,N-dimethylformamide solvent, stir evenly, and then mix with the first suspension obtained in step (1). Continue stirring, and then add 60 parts of acrylic monomer, 2 parts of thermosetting agent, and 4 parts of additives (polyurethane dispersant and fatty alcohol phosphate salt antistatic agent with a mass ratio of 1:3) to obtain the final coating liquid slurry; control the solid content of the coating liquid slurry to be maintained at 45 wt%;

[0106] (3) The obtained coating liquid is coated on the surface of the reflective film substrate. The thickness of the PET reflective film base film is 225 μm. The thickness of the (wet) coating is controlled to be about 40 μm. The film is placed in an oven at 110°C and baked for 2 min to obtain a fluorescent coated reflective film.

[0107] In addition, the present invention also provides a display module / display device having the above-mentioned fluorescent coating reflective film.

[0108] Example 2

[0109] In Example 1, the amount of TAP(Cu)-MAE fluorescent material was adjusted to 2 parts and the amount of PET particles was adjusted to 10 parts, while the other steps remained unchanged.

[0110] Example 3

[0111] In Example 1, the amount of TAP(Cu)-MAE fluorescent material was adjusted to 8 parts and the amount of PET particles to 10 parts, while the other steps remained unchanged.

[0112] Example 4

[0113] The fluorescent material in Example 1 was changed to TAP(Co)-MAE, while the other steps remained unchanged.

[0114] Example 5

[0115] The fluorescent material in Example 1 was changed to TAP-MAE, while the other steps remained unchanged.

[0116] Comparative Example 1

[0117] In Example 1, the fluorescent material was adjusted to be unmodified TAP(Cu), while the other steps remained unchanged. The unmodified TAP(Cu) refers to octamethylthiotetraazaporphyrin copper.

[0118] Comparative Example 2

[0119] In Example 1, the fluorescent material was adjusted to be unmodified TAP(Co), while the other steps remained unchanged. The unmodified TAP(Co) refers to cobalt octamethylthiotetraazaporphyrin.

[0120] Comparative Example 3

[0121] The fluorescent material in Example 1 was adjusted to TAP'(Cu), while the other steps remained unchanged. TAP'(Cu) refers to tetraazaporphyrin copper without methylthioyl substituents.

[0122] Comparative Example 4

[0123] The fluorescent material in Example 1 was adjusted to TAP'(Cu)-MAE, while the other steps remained unchanged. TAP'(Cu)-MAE refers to tetraazaporphyrin copper without methylthio substituents that has been pre-modified with acrylic anhydride.

[0124] Comparative Example 5

[0125] In Example 1, the amount of TAP(Cu)-MAE fluorescent material was adjusted to 0 parts, i.e., no tetrazaporphyrin fluorescent material was added, and the amount of PET particles was 10 parts, while the other steps remained unchanged.

[0126] The reflective films prepared in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests as follows:

[0127] (1) Brightness and brightness uniformity: Refer to GB / T 43979-2024, use BM-7A luminance colorimeter to test the brightness and brightness uniformity of the obtained sample; the higher the brightness uniformity, the more uniform the light output.

[0128] (2) Luminance and color coordinate test: The reflective films were assembled into a backlight in the following order from bottom to top: KSF lamp → reflective film → light guide plate → diffuser → prism sheet (90°) → prism sheet (0°) → diffuser. The luminance and color coordinate test was performed using a TOPCON BM-7A luminance meter.

[0129] (3) Reflectance test: The reflectance of the coated reflective film sample in the range of 360nm~740nm was tested using a HunterLab UltraScan VIS spectrophotometer.

[0130] The performance test results of the reflective films prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0131] Table 1 Performance test results of the reflective films prepared in Examples 1-5 and Comparative Examples 1-5

[0132]

[0133] As can be seen from the data in Examples 1-3 in the table, the color gamut improvement effect is significant with the increase of the concentration of tetrazaporphyrin compound. However, the addition of a large amount of tetrazaporphyrin compound will also cause a loss of luminance. Considering the balance between the color gamut improvement and luminance loss of the reflective film, the amount of tetrazaporphyrin compound added is crucial.

[0134] Furthermore, comparisons of Examples 1, 4, and 5, as well as Comparative Examples 1-5, show that the tetrazaporphyrin fluorescent material with alkylthio functional groups, after pre-modification, exhibits higher brightness uniformity in the resulting reflective film. Moreover, the change in reflectivity at 590nm after 800 hours of illumination is smaller, indicating better stability. The acrylic anhydride pre-modification treatment, on the one hand, acts on the periphery of the tetrazaporphyrin material, forming a certain coating effect, thus enhancing the dispersibility of the material in the subsequent coating slurry. Simultaneously, the formed coating layer is not a closed structure and does not affect the wavelength absorption and luminescence effect of the tetrazaporphyrin material in the coating. Secondly, the introduction of certain vinyl groups allows for chemical bonding with the main resin in the coating, further improving its dispersion uniformity and stability.

[0135] Comparative Examples 1 and 2 are based on the application effects of tetrazaporphyrins without pre-modification. The tetrazaporphyrin compounds in Comparative Examples 1 and 2 have methylthio groups in their structure. In contrast, Comparative Examples 3 and 4 are tetrazaporphyrin compounds prepared based on maleidonitrile without methylthio groups as precursors. Comparing the application data of Comparative Examples 1 to 4, the overall performance is similar with slight differences. Although Comparative Examples 3 to 4 were still pre-modified with acrylic anhydride, the main difference lies in the fact that the tetrazaporphyrin compounds used in Comparative Examples 3 to 4 do not have methylthio groups in their structure, that is, they do not have groups that react with acid anhydrides. Therefore, vinyl groups cannot be introduced, and after thermosetting, they cannot be chemically bonded to the main resin of the coating, thus ultimately affecting the application effect of the tetrazaporphyrin fluorescent material.

Claims

1. A fluorescent coated reflective film, comprising a reflective film substrate and a coating layer, wherein the coating layer is obtained by applying a coating liquid slurry to the surface of the reflective film substrate and then thermally curing it, characterized in that, The coating slurry comprises a pre-modified fluorescent material and a resin. The pre-modified fluorescent material is obtained by modifying a tetrazaporphyrin compound with an alkylthio group by a compound with an anhydride group. The compound with an anhydride group is one or more of acrylic anhydride or methacrylic anhydride. The general structural formula of the tetrazaporphyrin compound with an alkylthio group is as follows: In this group, M is a metal ion; at least one of R1 to R8 is a substituent of an alkylthio group, including methylthio or butylthio, and the others each independently include substituents of hydrogen atoms, halogen elements, branched or cyclic aliphatic hydrocarbon groups with 3 to 10 carbon atoms, aromatic hydrocarbon groups, hydroxyl groups, sulfonic acid groups, amino groups, aminoalkyl groups or cyano groups.

2. The fluorescent coated reflective film according to claim 1, characterized in that, The tetrazaporphyrin compound is obtained by condensation reaction of a precursor with a metal ion as a template in a solvent of n-propanol, n-butanol, trichlorobenzene, or quinoline; the metal ion is removed by acidification to obtain a free ligand tetrazaporphyrin; the free ligand tetrazaporphyrin is then reacted with different metal salts to obtain various metal tetrazaporphyrin complexes; the precursor is maleic anhydride and its derivatives, the derivatives including alkylthiomaleic anhydride.

3. The fluorescent coated reflective film according to claim 2, characterized in that, The coating liquid slurry, by weight, comprises: 2-8 parts of pre-modified fluorescent material, 60-80 parts of resin, 6-10 parts of compression-resistant particles, 1-3 parts of thermosetting agent, 3-5 parts of additives, and organic solvent in an amount required such that the solid content of the coating liquid slurry is maintained at 30-60 wt%.

4. The fluorescent coated reflective film according to claim 3, characterized in that, The resin is a mixture of at least one functional monomer containing a thiol group and at least one acrylic monomer or oligomer; the amount of the functional monomer containing a thiol group and the acrylic monomer or oligomer is 1:2 to 6 by mass; the functional monomer containing a thiol group includes one or more of trimethylolpropane tris(3-mercaptopropionic acid), pentaerythritol tetra(3-mercaptopropionic acid), ethylene glycol di(3-mercaptopropionic acid), 1,4-butanediol di(3-mercaptopropionic acid), mercaptoacrylate, mercaptomethacrylate, and 2-mercaptothiophene.

5. The fluorescent coated reflective film according to claim 4, characterized in that, The acrylic monomers include one or more of isobornyl acrylate, cyclotrimethylolpropane methyl acetal acrylate, 1,6-hexanediol diacrylate, propoxylated glycerol triacrylate, and tripropylene glycol diacrylate; the oligomers are acrylate oligomers, including one or more of aliphatic polyurethane acrylate, polyurethane acrylate, aromatic polyurethane acrylate, epoxy acrylate, epoxidized soybean oil acrylate, modified epoxy acrylate, epoxy methacrylate, aliphatic silicone acrylate, silicone polyurethane acrylate, polybutadiene dimethacrylate, polybutadiene diacrylate, polyester acrylate, acrylate polyester, and chlorinated polyester acrylate; the compression-resistant particles include one or more of polyethylene terephthalate, polymethyl methacrylate, polybutyl methacrylate, polyamide, and polyurethane, with a particle size of 1 μm to 60 μm.

6. The fluorescent coated reflective film according to claim 5, characterized in that, The reflective film substrate includes at least one of PET film and polypropylene film; the coating thickness is 20-50 μm.

7. A method for preparing a fluorescent coated reflective film according to any one of claims 1 to 6, characterized in that, Includes the following steps: (1) According to the formula, the pre-modified fluorescent material and the pressure-resistant particles are dispersed in the first solvent, ultrasonically dispersed for 1 to 3 hours, and stirred evenly to obtain the first suspension; (2) Resin addition: According to the formula, first dissolve the functional monomer containing thiol groups in the second solvent, stir evenly, and then mix with the first suspension obtained in step (1). Continue stirring, and then add acrylic monomers or oligomers, thermosetting agents, and additives in sequence to obtain the final coating liquid slurry; control the solid content of the coating liquid slurry to be maintained at 30-60 wt%; (3) The obtained coating liquid is applied to one side of the reflective film substrate and then heat-cured in an oven to obtain a fluorescent coated reflective film.

8. The method for preparing a fluorescent coated reflective film according to claim 7, characterized in that, The reflective film substrate includes at least one of PET film and polypropylene film; the thermosetting temperature is 100-120℃ and the reaction time is 1-3 min.

9. The method for preparing a fluorescent coated reflective film according to claim 8, characterized in that, The pre-modified fluorescent material is prepared by mixing a tetrazaporphyrin compound with a compound containing an anhydride group in a polar aprotic solvent, adding a catalyst under nitrogen protection, and reacting at 50–80°C for 18–36 hours; wherein the ratio of the tetrazaporphyrin compound to the compound containing anhydride group is 1:5–8 by molar weight; finally, the resulting solid is washed and dried to obtain the pre-modified tetrazaporphyrin compound fluorescent material.

10. The application of a fluorescent coated reflective film according to any one of claims 1 to 6, characterized in that, The reflective film is used in a display module / display device; the display module includes at least one of an LCD module and a Mini-LED module; the display device includes at least one of a television, a mobile phone, a laptop computer, and a vehicle central control screen.

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