Liquid crystal type anti-blue-light eye-protecting window film and preparation method thereof

Abstract

The invention discloses a liquid crystal type anti-blue-light eye-protection window film and a preparation method thereof, and relates to the technical field of optical thin films. The liquid crystal type anti-blue-light eye-protecting window film structurally comprises a scratch-resistant layer (4), a base material layer (3), a bonding adhesive (2), a liquid crystal layer (1), a bonding adhesive (2), a base material layer (3), a mounting adhesive layer (5) and a release layer (6) from top to bottom in sequence, the liquid crystal layer (1) is prepared from a liquid crystal mixture, and the liquid crystal mixture comprises the following components in percentage by mass: 30 to 60 percent of right-handed chiral nematic liquid crystal, 1 to 10 percent of right-handed chiral dopant, 20 to 35 percent of photosensitive monomer, 0.5 to 3 percent of photoinitiator, 10 to 30 percent of diluent and 0.1 to 1 percent of interfacial agent.

Description

Technical Field

[0001] The present invention relates to the technical field of optical thin films, and particularly to a liquid crystal type blue light blocking and eye protection window film and a preparation method thereof. Background Art

[0002] Medical research shows that blue light, especially short-wave blue light with a wavelength range of 415nm - 455nm, can cause various harms to the eyes due to its high energy characteristics, as follows: Damage to the retina: Short-wave blue light belongs to high-energy visible light (HEV light), which can penetrate the cornea and lens of the eye and reach the retina, causing photochemical damage. Short-wave blue light can cause retinal pigment epithelial cells (RPE) to generate excessive free radicals, leading to cellular oxidative stress and death. Prolonged exposure to blue light may damage the photosensitive pigments (such as rhodopsin) in retinal cells, causing irreversible retinal degeneration.

[0003] May induce macular lesions: The macula is the most sensitive part of the retina. Blue light irradiation may cause abnormal cell function in the macular area and is even related to the onset of age-related macular degeneration (AMD). Accelerate oxidative damage to the lens and cornea: Long-term exposure to blue light may accelerate lens oxidation, inducing or exacerbating cataracts. Although the cornea can absorb part of the short-wave blue light, its protective ability is limited, and long-term exposure may lead to corneal tissue inflammation.

[0004] Cause visual fatigue and dry eyes: Enhanced scattering: Short-wave blue light is prone to scattering in the human eye (mainly in the vitreous region), resulting in blurred vision and reduced contrast, thus increasing the eye burden. When people are driving or using electronic products, the strong and stimulating short-wave blue light will scatter in the human eye, causing visual blurring and dizziness. Blue light radiation may also interfere with the secretion of the tear film, leading to dry eyes.

[0005] Potential impact on children's eye development: The lenses of children are not fully developed, and their ability to filter blue light is poor. Therefore, the risk of blue light harming children's retinas is higher. Long-term exposure to blue light may increase the risk of myopia and eye fatigue in children.

[0006] Window films are widely used in automobiles, ships, and building glass. Especially in recent years, with the rapid development of the national economy, cars have entered thousands of households, and people use cars more frequently and for longer periods. Therefore, the time that the human eye is exposed to various lights is getting longer and longer. Especially when driving at night, a large amount of short-wave blue light is contained in various dazzling LED strong lights in the environment, which will cause a dazzling and dizzy feeling in the short term, resulting in driving fatigue and affecting driving safety. Long-term exposure will cause various eye injuries.

[0007] According to the guidelines published by the international organization ICNIRP (PUBLISHED IN: HEALTH PHYSICS 105(1):74‐96;2013), the eye damage coefficient of the 435nm wavelength in the full spectrum range is 1, reaching the maximum value. The blue light damage coefficients in the other bands of 415nm - 455nm are almost all above 0.9, and the blue light damage coefficients in the 460nm - 480nm band are 0.4 - 0.8.

[0008] The present invention plans to design an optical film that can be applied to the window films of automobiles or other transportation vehicles or electronic products to reduce blue light damage. Summary of the Invention

[0009] The purpose of the present invention is to provide a liquid crystal type blue light blocking and eye protection window film and its preparation method to solve the problems proposed in the prior art.

[0010] To achieve the above purpose, the present invention provides the following technical solutions: A liquid crystal type blue light blocking and eye protection window film, which includes the following structures from top to bottom: a scratch-resistant layer 4, a substrate layer 3, an adhesive layer 2, a liquid crystal layer 1, an adhesive layer 2, a substrate layer 3, an installation adhesive layer 5, and a release layer 6.

[0011] Further, the liquid crystal layer 1 is prepared from a liquid crystal mixture, and the proportion of each component in the liquid crystal mixture is calculated by mass percentage and includes: 30 - 60wt% of right-handed chiral nematic liquid crystal, 1 - 10wt% of right-handed chiral dopant, 20 - 35wt% of photosensitive monomer, 0.5 - 3wt% of photoinitiator, 10 - 30wt% of diluent, and 0.1 - 1% of surfactant.

[0012] Further, the right-handed chiral nematic liquid crystal model includes any one of Merck E7 liquid crystal, MLC-6608, E44, and B2; Further, the right-handed chiral dopant includes any one of CB15, R5011, and S811; Further, the photosensitive monomer includes polyurethane acrylate; Further, the photoinitiator includes any one of TMPTA and HEA; Further, the diluent includes any one of alcohols, ethers, and toluene solvents; Further, the surfactant includes BYK-341; Further, the thickness of the liquid crystal layer 1 is 1 - 20μm; the thickness of the adhesive layer 2 is 1 - 5μm; the thickness of the substrate layer 3 is 10 - 200μm; the thickness of the scratch-resistant layer 4 is 1 - 5μm; the thickness of the installation adhesive layer 5 is 10 - 30μm.

[0013] Further, the composition of the bonding adhesive 2 is any one of acrylic pressure-sensitive adhesives or acrylic photocurable adhesives; the composition of the substrate layer 3 is any one of transparent glass or polymer films; the scratch-resistant layer 4 is prepared from a scratch-resistant coating, and the composition of the scratch-resistant coating is any one of acrylate photocurable adhesives or modified acrylic polymer coatings; the mounting adhesive layer 5 is prepared from a mounting adhesive, and the composition of the mounting adhesive is any one of acrylic pressure-sensitive adhesives, silicone rubber, and polyurethane adhesives; the release layer 6 is prepared from a release film.

[0014] Further, the proportion of each component in the modified acrylic polymer coating by mass percentage includes: 3-4.5 wt% acrylic resin, 1-4 wt% phthalic anhydride, 0.2-0.3 wt% triarylsulfonium hexafluorophosphate, 6-9 wt% modified epoxy resin, 1-4 wt% perfluorohexyl-modified POSS, and the balance is methylene chloride.

[0015] Further, the preparation method of the modified epoxy resin includes the following steps: Step A: Add 711 epoxy resin, acrylic acid, 3,3'-dithiodipropionic acid, and hydroquinone into a reaction vessel. Under a nitrogen atmosphere, add tetrabutylammonium bromide, heat to 90-92 °C and react for 1-1.5 h, then heat to 110-115 °C and react for 2-2.5 h to obtain modified acrylic epoxy resin; Step B: Add 3,4-epoxycyclohexyl methacrylate, modified acrylic epoxy resin, azobisisobutyronitrile, and anhydrous tetrahydrofuran into a reaction vessel. Under a nitrogen atmosphere, heat to 60-65 °C and react for 12-14 h. Cool to room temperature, add the product solution to an excess of hexane to form a polymer precipitate, centrifuge and sediment the polymer, remove the supernatant, obtain a crude product, add the crude product to anhydrous tetrahydrofuran, precipitate again in an excess of hexane, and perform one purification cycle. Rotate and evaporate to dryness to obtain the modified epoxy resin.

[0016] Further, in the preparation process of the modified acrylic epoxy resin, the mass ratio of 711 epoxy resin: acrylic acid: 3,3'-dithiodipropionic acid is (8-10):(2-2.3):(1-1.3); the addition amount of hydroquinone is 0.2-0.3 wt% of the mass of acrylic acid; in the preparation process of the modified epoxy resin, the mass ratio of modified acrylic epoxy resin: 3,4-epoxycyclohexyl methacrylate: azobisisobutyronitrile is (7.7-8.5):(1.5-3.3):(0.03-0.04).

[0017] Furthermore, the preparation method of the perfluorohexyl-modified POSS includes the following steps: Add epoxycyclohexyl POSS, tridecafluoroheptanoic acid, and tetrabutylammonium bromide into 1,4-dioxane, heat to reflux for 8 - 10 h, cool to room temperature, rotary evaporate and dry. Add the product into chloroform, extract twice with 0.1 M aqueous sodium bicarbonate solution, then extract twice with deionized water. Dry the chloroform layer with anhydrous magnesium sulfate, filter, rotary evaporate and dry to obtain the crude product. Add the crude product into acetonitrile, filter, and vacuum dry to obtain the perfluorohexyl-modified POSS.

[0018] Furthermore, during the preparation of the perfluorohexyl-modified POSS, the molar ratio of epoxycyclohexyl POSS : tridecafluoroheptanoic acid : tetrabutylammonium bromide is (7.47 - 7.96) : (4.11 - 4.32) : (1.33 - 1.42).

[0019] A preparation method of a liquid crystal type anti-blue light and eye-protecting window film, characterized by including the following steps: S1: Mix the right-handed chiral nematic liquid crystal, right-handed chiral dopant, photosensitive monomer, photoinitiator, diluent, and surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 60 - 120 °C, and perform photocuring to obtain the liquid crystal layer 1; S2: Peel the liquid crystal layer 1 from the substrate layer 3, coat the bonding glue 2 on the upper and lower surfaces of the liquid crystal layer 1 respectively, and bond the substrate layer 3 on the surfaces of the upper and lower bonding glues 2 of the liquid crystal layer 1, and perform curing treatment; S3: Coat the scratch-resistant coating on the surface of one side of the substrate layer 3, and perform curing treatment to obtain the scratch-resistant layer 4; S4: Coat the mounting glue on the surface of the other layer of the substrate layer 3, bond the release film on the surface of the mounting glue, and perform curing treatment to obtain the liquid crystal type anti-blue light and eye-protecting window film.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The present invention utilizes the basic characteristics of Bragg reflection of photonic crystals in the self-made liquid crystal layer, selectively reflects the spectrum of a specific band, realizes efficient reflection of the target wavelength to block harmful blue light, adopts liquid crystal coating reflection, avoids the color deviation or fading problems caused by traditional absorption methods, and further makes the liquid crystal type anti-blue light and eye-protecting window film thinner and lighter, greatly improving the application scenarios of the liquid crystal type anti-blue light and eye-protecting window film.

[0021] 2. The present invention selects high-transparency and high-light transmittance 711 epoxy resin as the matrix resin, and prepares a modified acrylic epoxy resin by reacting with acrylic acid and 3,3'-dithiobipropionic acid. Introduce dynamic disulfide link segments into the resin matrix, endow the coating with excellent self-healing performance, and greatly improve the wear resistance of the scratch-resistant layer during actual application.

[0022] 3. Based on the modified acrylic epoxy resin, 3,4-epoxycyclohexyl methacrylate with a group structure similar to that of perfluorohexyl-modified POSS is used as a monomer to copolymerize with the modified acrylic epoxy resin to prepare a modified epoxy resin. Utilizing its property of similar solubility, the dispersibility and compatibility of the modified epoxy resin and perfluorohexyl-modified POSS in the acrylic resin are greatly improved.

[0023] 4. Graft epoxycyclohexyl POSS with tridecafluoroheptanoyl to modify it. Utilizing its property as a fluorinating agent, the anti-fouling and fingerprint-inhibiting properties of the liquid crystal anti-blue light and eye-protecting window film can be greatly improved.

[0024] 5. In the present invention, further, perfluorohexyl-modified POSS, as an inorganic filler with the characteristics of being hard and brittle, is combined with the flexible characteristics of organic materials (acrylic resin, modified epoxy resin). The cycloaliphatic epoxy-functionalized modified epoxy resin, perfluorohexyl-modified POSS, and thermosetting hydroxy-functionalized acrylic resin are crosslinked with the crosslinking agent phthalic anhydride to form a highly crosslinked organic-inorganic coating network. Two different curing materials are mixed, and a double-curing process of ultraviolet irradiation-induced epoxy ring-opening polymerization and heat treatment curing of epoxy groups, hydroxyl groups, and anhydride groups is introduced. Through the synergistic effect of different curing characteristics, the wear resistance of the coating is maximally improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of a liquid crystal anti-blue light and eye-protecting window film of the present invention; Among them, liquid crystal layer 1, bonding adhesive 2, substrate layer 3, scratch-resistant layer 4, installation adhesive layer 5, release layer 6.

[0026] Figure 2 It is a transmittance spectrogram of incident light at different angles in Example 8 of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0028] In the following examples, the model of 711 epoxy resin is Epikote 190; the model of right-handed chiral nematic liquid crystal is Merck E7 liquid crystal; the model of right-handed chiral dopant is CB15; the photosensitive monomer is polyurethane acrylate; the photoinitiator is TMPTA; the model of surfactant is BYK-341; the specification of PET film is haze ≤ 1.5% and light transmittance ≥ 90%; the model of acrylate photocurable adhesive is DSP 3195DM; the model of acrylic resin is KN7760T thermosetting acrylic resin; the rest of the raw materials are commercially available.

[0029] The preparation method of modified epoxy resin includes the following steps: Step A: Add 8 g of 711 epoxy resin, 2 g of acrylic acid, 1 g of 3,3'-dithiobispropionic acid, and 0.04 g of hydroquinone into a reaction vessel. Under a nitrogen atmosphere, add 0.3 g of tetrabutylammonium bromide, heat to 90 °C and react for 1 h, then heat to 110 °C and react for 2 h to obtain modified acrylic epoxy resin. Step B: Add 7.7 g of 3,4-epoxycyclohexyl methacrylate, 1.5 g of modified acrylic epoxy resin, 0.03 g of azobisisobutyronitrile, and 120 mL of anhydrous tetrahydrofuran into a reaction vessel. Under a nitrogen atmosphere, heat to 60 °C and react for 12 h. Cool to room temperature, add the product solution to excess hexane to form a polymer precipitate, centrifuge and sediment the polymer, remove the supernatant to obtain a crude product. Add the crude product into anhydrous tetrahydrofuran and precipitate it again in excess hexane. Purify it by cycling once, and rotary evaporate to dryness to obtain modified epoxy resin.

[0030] The preparation method of perfluorohexyl-modified POSS includes the following steps: Add 7.47 mmol of epoxycyclohexyl POSS, 4.11 mmol of tridecafluoroheptanoic acid, and 1.33 mmol of tetrabutylammonium bromide into 50 mL of 1,4-dioxane, heat to reflux and react for 8 h, cool to room temperature, rotary evaporate to dryness. Add the product into chloroform, extract it twice with 0.1 M aqueous sodium bicarbonate solution, then extract it twice with deionized water. Dry the chloroform layer with anhydrous magnesium sulfate, filter, rotary evaporate to dryness to obtain a crude product. Add the crude product into acetonitrile, filter, and vacuum dry to obtain perfluorohexyl-modified POSS.

[0031] Example 1: The preparation method of a liquid crystal type anti-blue light and eye protection window film: includes the following steps: S1: Mix 30 wt% of right-handed chiral nematic liquid crystal, 5 wt% of right-handed chiral dopant, 35 wt% of photosensitive monomer, 2 wt% of photoinitiator, 27 wt% of diluent, and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of substrate layer 3, volatilize the solvent at 80 °C, and photocure to obtain liquid crystal layer 1. S2: Peel the liquid crystal layer 1 from the substrate layer 3, coat the acrylic pressure-sensitive adhesive bonding adhesive 2 on the upper and lower surfaces of the liquid crystal layer 1 respectively, bond the PET film substrate layer 3 on the surfaces of the upper and lower acrylic pressure-sensitive adhesive bonding adhesives 2 of the liquid crystal layer 1, and perform heat curing treatment; S3: Coat the acrylate photocurable adhesive on the surface of one substrate layer 3, perform photocuring treatment to obtain the scratch-resistant layer 4; S4: Coat the acrylic pressure-sensitive adhesive on the surface of the other substrate layer 3, bond the PET release film on the surface of the mounting adhesive, and perform heat curing treatment to obtain the liquid crystal type blue light blocking and eye protection window film.

[0032] In Example 1, the thickness of the liquid crystal layer 1 is 1 μm, the thickness of the bonding adhesive 2 is 1 μm, the thickness of the substrate layer 3 is 23 μm, the thickness of the scratch-resistant layer 4 is 5 μm; the thickness of the mounting adhesive layer 5 is 10 μm.

[0033] Example 2: A method for preparing a liquid crystal type blue light blocking and eye protection window film: includes the following steps: S1: Mix 40 wt% of right-handed chiral nematic liquid crystal, 5 wt% of right-handed chiral dopant, 30 wt% of photosensitive monomer, 2 wt% of photoinitiator, 22 wt% of diluent and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; The remaining steps are the same as those in Example 1.

[0034] Example 3: A method for preparing a liquid crystal type blue light blocking and eye protection window film: includes the following steps: S1: Mix 50 wt% of right-handed chiral nematic liquid crystal, 5 wt% of right-handed chiral dopant, 25 wt% of photosensitive monomer, 2 wt% of photoinitiator, 17 wt% of diluent and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; The remaining steps are the same as those in Example 1.

[0035] Example 4: A method for preparing a liquid crystal type blue light blocking and eye protection window film: includes the following steps: S1: Mix 60 wt% of right-handed chiral nematic liquid crystal, 5 wt% of right-handed chiral dopant, 20 wt% of photosensitive monomer, 2 wt% of photoinitiator, 12 wt% of diluent and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; The remaining steps are the same as those in Example 1.

[0036] Example 5: A method for preparing a liquid crystal type blue light blocking and eye protection window film: In Example 5, the thickness of the liquid crystal layer 1 is 3 μm, The remaining steps are the same as those in Example 1.

[0037] Example 6: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 6, the thickness of the liquid crystal layer 1 is 3 μm, The remaining steps are the same as those in Example 2.

[0038] Example 7: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 7, the thickness of the liquid crystal layer 1 is 3 μm, The remaining steps are the same as those in Example 3.

[0039] Example 8: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 8, the thickness of the liquid crystal layer 1 is 3 μm, The remaining steps are the same as those in Example 4.

[0040] Example 9: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 9, the thickness of the liquid crystal layer 1 is 5 μm, The remaining steps are the same as those in Example 1.

[0041] Example 10: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 10, the thickness of the liquid crystal layer 1 is 5 μm, The remaining steps are the same as those in Example 2.

[0042] Example 11: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 11, the thickness of the liquid crystal layer 1 is 5 μm, The remaining steps are the same as those in Example 3.

[0043] Example 12: A preparation method of a liquid crystal type blue light blocking and eye protection window film: In Example 12, the thickness of the liquid crystal layer 1 is 5 μm, The remaining steps are the same as those in Example 4.

[0044] Example 13: A preparation method of a liquid crystal type blue light blocking and eye protection window film: The method includes the following steps: S1: Mix 60 wt% of dextrorotatory chiral nematic liquid crystal, 5 wt% of dextrorotatory chiral dopant, 20 wt% of photosensitive monomer, 2 wt% of photoinitiator, 12 wt% of diluent and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; S2: Peel the liquid crystal layer 1 from the substrate layer 3, coat acrylic pressure-sensitive adhesive bonding agent 2 on the upper and lower surfaces of the liquid crystal layer 1 respectively, and bond the PET film substrate layer 3 on the upper and lower surfaces of the acrylic pressure-sensitive adhesive bonding agent 2 of the liquid crystal layer 1, and perform heat curing treatment; S3: Add 3 wt% of acrylic resin, 1 wt% of phthalic anhydride, 0.2 wt% of triarylsulfonium hexafluorophosphate, 6 wt% of modified epoxy resin, 1 wt% of perfluorohexyl modified POSS into 88.8 wt% of dichloromethane in sequence, stir evenly to obtain a modified acrylic polymer coating; S4: Coat the surface of one substrate layer 3 with the modified acrylic polymer coating, dry at 70 °C for 20 min to remove the solvent, cure under ultraviolet light for 30 min, and thermally cure at 140 °C for 30 min to obtain the scratch-resistant layer 4; S5: Coat the surface of another substrate layer 3 with the acrylic pressure-sensitive adhesive, laminate the PET release film on the surface of the mounting adhesive, and perform thermal curing treatment to obtain the liquid crystal type anti-blue light and eye protection window film.

[0045] In Example 1, the thickness of the liquid crystal layer 1 is 3 μm, the thickness of the bonding adhesive 2 is 1 μm, the thickness of the substrate layer 3 is 23 μm, the thickness of the scratch-resistant layer 4 is 5 μm; the thickness of the mounting adhesive layer 5 is 10 μm.

[0046] Example 14: A method for preparing a liquid crystal type anti-blue light and eye protection window film: The method includes the following steps: S3: Add 4.5 wt% acrylic resin, 4 wt% phthalic anhydride, 0.3 wt% triarylsulfonium hexafluorophosphate, 9 wt% modified epoxy resin, and 4 wt% perfluorohexyl-modified POSS to 78.2 wt% dichloromethane in sequence, stir evenly to obtain the modified acrylic polymer coating; The remaining steps are the same as those in Example 13.

[0047] Comparative Example 1: A method for preparing a liquid crystal type anti-blue light and eye protection window film: The method includes the following steps: S1: Mix 70 wt% of dextrorotatory chiral nematic liquid crystal, 5 wt% of dextrorotatory chiral dopant, 15 wt% of photosensitive monomer, 2 wt% of photoinitiator, 7 wt% of diluent, and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; S2: Peel the liquid crystal layer 1 from the substrate layer 3, coat the acrylic pressure-sensitive adhesive bonding adhesive 2 on the upper and lower surfaces of the liquid crystal layer 1 respectively, and laminate the PET film substrate layer 3 on the upper and lower surfaces of the acrylic pressure-sensitive adhesive bonding adhesive 2 of the liquid crystal layer 1, and perform thermal curing treatment; S3: Coat the acrylate photocurable adhesive on the surface of one substrate layer 3, and perform photocuring treatment to obtain the scratch-resistant layer 4; S4: Coat the acrylic pressure-sensitive adhesive on the surface of another substrate layer 3, laminate the PET release film on the surface of the mounting adhesive, and perform thermal curing treatment to obtain the liquid crystal type anti-blue light and eye protection window film.

[0048] In Comparative Example 1, the thickness of the liquid crystal layer 1 is 1 μm, the thickness of the bonding adhesive 2 is 1 μm, the thickness of the substrate layer 3 is 23 μm, the thickness of the scratch-resistant layer 4 is 5 μm; the thickness of the mounting adhesive layer 5 is 10 μm.

[0049] Comparative Example 2: A preparation method of a liquid crystal type blue light blocking and eye protection window film: The method comprises the following steps: S1: Mix 30 wt% of dextrorotatory chiral nematic liquid crystal, 5 wt% of dextrorotatory chiral dopant, 35 wt% of photosensitive monomer, 2 wt% of photoinitiator, 27 wt% of diluent and 1 wt% of surfactant evenly according to the ratio to obtain a liquid crystal mixture; coat the liquid crystal mixture on the surface of the substrate layer 3, volatilize the solvent at 80 °C, and perform photocuring to obtain the liquid crystal layer 1; S2: Peel the liquid crystal layer 1 from the substrate layer 3, coat acrylic pressure-sensitive adhesive bonding glue 2 on the upper and lower surfaces of the liquid crystal layer 1 respectively, and bond the PET film substrate layer 3 on the surfaces of the upper and lower acrylic pressure-sensitive adhesive bonding glue 2 of the liquid crystal layer 1, and perform heat curing treatment; S3: Coat acrylate photocurable glue on the surface of one side of the substrate layer 3, and perform photocuring treatment to obtain the scratch-resistant layer 4; S4: Coat acrylic pressure-sensitive adhesive on the surface of the other substrate layer 3, bond the PET release film on the surface of the mounting adhesive, and perform heat curing treatment to obtain the liquid crystal type blue light blocking and eye protection window film.

[0050] In Comparative Example 2, the thickness of the liquid crystal layer 1 is 7 μm, the thickness of the bonding glue 2 is 1 μm, the thickness of the substrate layer 3 is 23 μm, the thickness of the scratch-resistant layer 4 is 5 μm; the thickness of the mounting adhesive layer 5 is 10 μm.

[0051] Comparative Example 3: A preparation method of a liquid crystal type blue light blocking and eye protection window film: The method comprises the following steps: S3: Add 5 wt% of acrylic resin, 4.5 wt% of phthalic anhydride, 0.4 wt% of triarylsulfonium hexafluorophosphate, 10.5 wt% of modified epoxy resin, 6 wt% of perfluorohexyl modified POSS into 73.6 wt% of dichloromethane in sequence, and stir evenly to obtain a modified acrylic polymer coating; The remaining steps are the same as those in Example 13.

[0052] Experiment: Blue light blocking optical performance test: Measure the transmittance and reflectance of the full spectrum of the incident light at 90° with a spectrophotometer. The experimental results are shown in Table 1 below.

[0053] Table 1 Data sheet of reflectance / transmittance performance test of liquid crystal type blue light blocking and eye protection window film

[0054] Conclusion: From the above experiments, it is obtained that when the liquid crystal concentration is 60% and the thickness of the liquid crystal layer is 3 μm, that is, the comprehensive performance of the liquid crystal type blue light blocking and eye protection window film prepared in Example 8 is the best.

[0055] Comparative Example 1 increased the proportion of the liquid crystal concentration. Although the reflectance at 435 nm was increased, the overall transmittance was greatly reduced, and the comprehensive performance was reduced.

[0056] Comparative Example 2 increased the thickness of the liquid crystal layer. Although the reflectivity at 435 nm was increased, the overall transmittance was greatly reduced, resulting in a decrease in comprehensive performance.

[0057] On the basis of Example 13, Comparative Example 3 increased the proportion of each component in the modified acrylic polymer coating, resulting in a decrease in dispersion performance and affecting the final light transmittance performance of the liquid crystal type anti-blue light and eye-protecting window film.

[0058] Experiment: The liquid crystal type anti-blue light and eye-protecting window films prepared in Example 8, Example 13, Example 15, and Comparative Example 3 were subjected to wear resistance tests; nanoindentation analysis was performed using a nanoindenter. The maximum load was set at 200 mN. The force loading and unloading rate was 10 mN / s, and the holding time after reaching the maximum load was 1 s. The experimental results are shown in Table 2 below.

[0059] Table 2 Data table of wear resistance test of liquid crystal type anti-blue light and eye-protecting window film

[0060] Conclusion: On the basis of Example 8, Example 13 and Example 14 further optimized the coating components of the scratch-resistant layer 4, and greatly improved the scratch resistance and wear resistance of the liquid crystal type anti-blue light and eye-protecting window film on the premise of retaining the best comprehensive performance of the liquid crystal type anti-blue light and eye-protecting window film. Although Comparative Example 3 has excellent wear resistance, according to the experimental data in Table 1, its light transmittance is greatly reduced and the comprehensive performance is reduced.

[0061] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claimed claims.

Claims

1. A liquid crystal anti-blue light eye protection window film, characterized in that: The liquid crystal type anti-blue light eye protection window film comprises the following structure: from top to bottom, a scratch-resistant layer (4), a substrate layer (3), a bonding adhesive (2), a liquid crystal layer (1), a bonding adhesive (2), a substrate layer (3), a mounting adhesive layer (5), and a release layer (6).

2. The liquid crystal anti-blue light eye protection window film according to claim 1, characterized in that: The liquid crystal layer (1) is prepared from a liquid crystal mixture, wherein the components in the liquid crystal mixture include, by weight percentage: 30-60 wt% of right-handed chiral nematic liquid crystal, 1-10 wt% of right-handed chiral dopant, 20-35 wt% of photosensitive monomer, 0.5-3 wt% of photoinitiator, 10-30 wt% of diluent and 0.1-1% of surfactant.

3. The liquid crystal anti-blue light eye protection window film according to claim 1, characterized in that: The thickness of the liquid crystal layer (1) is 1-20 μm; the thickness of the bonding adhesive (2) is 1-5 μm; the thickness of the substrate layer (3) is 10-200 μm; the thickness of the scratch-resistant layer (4) is 1-5 μm; and the thickness of the mounting adhesive layer (5) is 10-30 μm.

4. The liquid crystal anti-blue light eye protection window film according to claim 1, characterized in that: The bonding adhesive (2) is composed of any one of acrylic pressure-sensitive adhesive and acrylic light-curing adhesive; the substrate layer (3) is composed of any one of transparent glass and polymer film; the scratch-resistant layer (4) is prepared from a scratch-resistant coating, and the scratch-resistant coating is composed of any one of acrylic light-curing adhesive and modified acrylic polymer coating; the mounting adhesive layer (5) is prepared from mounting adhesive, and the mounting adhesive is composed of any one of acrylic pressure-sensitive adhesive, silicone and polyurethane glue; the release layer (6) is prepared from a release film.

5. The liquid crystal anti-blue light eye protection window film according to claim 4, characterized in that: The components in the modified acrylic polymer coating include, by mass percentage, 3-4.5wt% acrylic resin, 1-4wt% phthalic anhydride, 0.2-0.3wt% triarylsulfonium hexafluorophosphate, 6-9wt% modified epoxy resin, 1-4wt% perfluorohexyl modified POSS, and the rest is dichloromethane.

6. The liquid crystal anti-blue light eye protection window film according to claim 5, characterized in that: The preparation method of the modified epoxy resin comprises the following steps: step A: adding 711 epoxy resin, acrylic acid, 3,3'-dithiodipropionic acid and hydroquinone into a reaction container, adding tetrabutylammonium bromide under a nitrogen atmosphere, heating to 90-92° C. for reaction for 1-1.5 hours, and then heating to 110-115° C. for reaction for 2-2.5 hours to obtain a modified acrylic epoxy resin; Step B: Add 3,4-epoxycyclohexyl methacrylate, modified acrylic epoxy resin, azobisisobutyronitrile and anhydrous tetrahydrofuran into a reaction vessel, heat to 60-65° C. under nitrogen atmosphere for 12-14 hours, cool to room temperature, purify and obtain modified epoxy resin.

7. The liquid crystal anti-blue light eye protection window film according to claim 6, characterized in that: In the preparation process of modified acrylic epoxy resin, the mass ratio of 711 epoxy resin: acrylic acid: 3,3'-dithiodipropionic acid is (8-10): (2-2.3): (1-1.3); the amount of hydroquinone added is 0.2-0.3wt% of the mass of acrylic acid; in the preparation process of modified epoxy resin, the mass ratio of modified acrylic epoxy resin: 3,4-epoxycyclohexyl methacrylate: azobisisobutyronitrile is (7.7-8.5): (1.5-3.3): (0.03-0.04).

8. The liquid crystal anti-blue light eye protection window film according to claim 5, characterized in that: The preparation method of the perfluorohexyl modified POSS comprises the following steps: adding epoxy cyclohexyl POSS, tridecafluoroheptanoic acid and tetrabutylammonium bromide into 1,4-dioxane, heating to reflux reaction for 8-10 hours, cooling to room temperature, and purifying to obtain the perfluorohexyl modified POSS.

9. The liquid crystal anti-blue light eye protection window film according to claim 8, characterized in that: In the preparation process of perfluorohexyl modified POSS, the molar ratio of epoxycyclohexyl POSS: tridecafluoroheptanoic acid: tetrabutylammonium bromide is (7.47-7.96):(4.11-4.32):(1.33-1.42).

10. A method for preparing a liquid crystal anti-blue light eye protection window film, characterized in that: The following steps are involved: S1: mixing right-handed chiral nematic liquid crystal, right-handed chiral dopant, photosensitive monomer, photoinitiator, diluent and surfactant in a uniform ratio to obtain a liquid crystal mixture; coating the liquid crystal mixture on the surface of the substrate layer (3), volatilizing the solvent at 60-120° C., and photocuring to obtain a liquid crystal layer (1); S2: peeling the liquid crystal layer (1) and the substrate layer (3), coating the bonding adhesive (2) on the upper and lower surfaces of the liquid crystal layer (1) respectively, bonding the substrate layer (3) to the upper and lower surfaces of the bonding adhesive (2) of the liquid crystal layer (1), and performing a curing treatment; S3: coating a scratch-resistant coating on the surface of one side of the substrate layer (3), and performing a curing treatment to obtain a scratch-resistant layer (4); S4: coating the mounting adhesive on the surface of another substrate layer (3), laminating the release film on the surface of the mounting adhesive, and performing a curing treatment to obtain a liquid crystal type anti-blue light eye protection window film.

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