A coating for polycarbonate, its preparation method and application, and a filter device

Abstract

The present invention provides a coating for polycarbonate, a preparation method and application thereof, and a filter device, belonging to the technical field of coating technology for filter devices. The coating for polycarbonate comprises the following components in parts by weight: 10-20 parts of polyhydroxy acrylate resin, 1-10 parts of isocyanate curing agent, 0-20 parts of infrared absorber, 1-10 parts of ultraviolet absorber, 0.1-5 parts of surfactant, and 60-80 parts of composite solvent; wherein, the composite solvent comprises a solvent with a large molecular weight and a solvent with a small molecular weight; the molecular weight of the solvent with a large molecular weight is ≥90 g / mol, and the molecular weight of the solvent with a small molecular weight is <90 g / mol. The coating for polycarbonate of the present invention solves the problems that the solvent in the coating corrodes the PC, resulting in a large haze and easy whitening, the PC is not resistant to UV and is prone to yellowing and powdering, and the viscosity of the coating is large, and it is easy to occur flow marks, peeling, vertical stripes and other problems.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings for filter devices, and particularly relates to a coating for polycarbonate, a preparation method and application thereof, and a filter device. Background Art

[0002] The polarizer device is one of the indispensable structural components of liquid crystal displays. Its function is to convert non-polarized natural light into polarized light in a certain polarization direction, so that the liquid crystal panel has the possibility of imaging. The basic structure of the polarizer is an optical composite laminate formed by laminating multiple film materials. Recently, protective films prepared from various materials that can replace PVA films and TAC films have been researched and developed, such as polyethylene terephthalate (PET), cycloolefin polymer film (COP), polycarbonate film (PC), etc.

[0003] Automotive optical devices such as in-vehicle camera covers, HUD covers, display panels, etc.; due to their requirements for explosion protection (preventing fragmentation and splashing), high transparency, and flame retardancy, and based on polycarbonate (PC) because of its outstanding impact toughness, transparency, and dimensional stability, excellent mechanical strength, electrical insulation, wide use temperature range, good creep resistance, weather resistance, low water absorption, non-toxicity, and self-extinguishing properties, polycarbonate film (PC) materials are usually selected. However, as an optical device, PC materials have the following disadvantages:

[0004] 1. Polycarbonate is a linear carbonate polyester in which carbonate groups and other groups are arranged alternately in the molecule. These groups can be aromatic, aliphatic, or both. Polycarbonate molecules contain strongly polar carbonyl groups and dioxy bonds (-O-R-O-), and the intermolecular forces are relatively strong, which makes PC have excellent mechanical properties and heat resistance; however, precisely because the molecular network is loose and contains a large number of ester groups, polycarbonate has the disadvantage of poor solvent resistance. In an organic solvent and alkaline solution environment, polycarbonate is very likely to swell and stress crack, resulting in the scrapping of products. It has been found through testing that solvents such as acetone, butanone, cyclohexanone, toluene, ethyl acetate, chloromethane, dichloroethane, and dimethylformamide will all show a whitening and fogging phenomenon when individually coated on the surface of a PC substrate, and it is not resistant to organic solvents.

[0005] 2. The PC substrate will turn yellow when exposed to ultraviolet light for a long time, is prone to yellowing and powdering, and is easily eroded by certain organic solvents.

[0006] 3. Since coatings for PC substrates usually require the addition of infrared absorbers and ultraviolet absorbers, and these materials are mostly nanoparticles. Nanoparticles have a very high specific surface area and surface free energy and are in a thermodynamically unstable state, resulting in extremely easy aggregation of nanoparticles into clusters and difficult uniform dispersion. Therefore, the nano-slurry is prone to problems such as low concentration, large average particle size, poor transparency in the visible light region, easy aggregation and precipitation during storage, etc., leading to unsatisfactory heat insulation and ultraviolet resistance effects.

[0007] 4. During the process of coating on the surface of the PC substrate, due to the high viscosity and poor performance of the coating, phenomena such as sagging, peeling, and vertical streaks are likely to occur.

[0008] 5. Most resin materials have poor adhesion and bonding ability to the surface of polycarbonate. Also, due to the difference in the thermal expansion coefficients between the PC substrate material and the thin film material, thermal stress will be generated in the thin film, and excessive stress will cause the film layer to crack or even peel off, such as polyurethane, etc.

[0009] In view of this, the present invention is specifically proposed. Summary of the Invention

[0010] The object of the present invention is to provide a coating for polycarbonate, its preparation method and application, and a filter device. The coating for polycarbonate solves the problems of large haze and easy whitening caused by solvent corrosion in part, easy yellowing and powdering of PC due to intolerance to UV, and high viscosity of the coating, which is prone to sagging, peeling, vertical streaks, etc.

[0011] In order to achieve the above object of the present invention, the following technical solutions are specifically adopted:

[0012] In the first aspect, the present invention provides a coating for polycarbonate, which includes the following components by weight:

[0013] 10 - 20 parts of polyhydroxy acrylic resin

[0014] 1 - 10 parts of isocyanate curing agent

[0015] 0 - 20 parts of infrared absorber

[0016] 1 - 10 parts of ultraviolet absorber

[0017] 0.1 - 5 parts of surfactant

[0018] 60 - 80 parts of composite solvent;

[0019] Among them, the composite solvent includes a solvent with a large molecular weight and a solvent with a small molecular weight; the molecular weight of the solvent with a large molecular weight ≥ 90 g / mol, and the molecular weight of the solvent with a small molecular weight < 90 g / mol.

[0020] Preferably, the mass ratio of the solvent with a large molecular weight to the solvent with a small molecular weight is (8.5~9.8):(0.2~1.5).

[0021] Preferably, the solvent with a large molecular weight is selected from N any one or a combination of at least two of N-methyl-2-pyrrolidone, cyclohexanone, xylene, n-butyl acetate, propylene glycol methyl ether acetate or light aromatic solvent oil.

[0022] Preferably, the solvent with a small molecular weight is selected from any one or a combination of at least two of isopropyl alcohol, methyl ethyl ketone or ethyl acetate.

[0023] Preferably, the surfactant is selected from any one or a combination of at least two of alkyl sulfates with C12 or above, linear alcohol polyoxyethylene ether sulfates, sulfated triglycerides, polyoxyethylene alkyl phenols, linear alcohol polyoxyethylene ethers, polyether-modified polydimethylsiloxanes or polyureas.

[0024] Preferably, the hydroxyl value of the polyhydroxy acrylic resin is 10~150 mgKOH / g.

[0025] Preferably, the isocyanate curing agent is selected from hexamethylene diisocyanate and / or isophorone diisocyanate.

[0026] Preferably, the infrared absorber includes an organic dye and a metal oxide.

[0027] Preferably, the mass ratio of the organic dye to the metal oxide is (0.05~2):(8~10).

[0028] Preferably, the organic dye is selected from indole-based near-infrared fluorescent organic dyes.

[0029] Preferably, the organic dye is selected from any one or a combination of at least two of IR780, IR820, IR956, IR1008 or IR1086.

[0030] Preferably, the metal oxide is selected from nano rare earth metal oxide powders, the particle size of the nano rare earth metal oxide powders is 20~50 nm, and the specific surface area of the nano rare earth metal oxide powders is 30~60 m 2 / g.

[0031] Preferably, the metal oxide is selected from any one or a combination of at least two of tungsten oxide, tungsten cesium oxide, tungsten gold vanadium oxide, tungsten vanadium tin antimony oxide, cesium tungsten bronze.

[0032] Preferably, the ultraviolet absorber is selected from any one or a combination of at least two of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers or phenylbenzimidazole ultraviolet absorbers.

[0033] Preferably, the benzotriazole ultraviolet absorber is selected from any one or a combination of at least two of UV326, UV327, UV329 or UVP.

[0034] Preferably, the triazine ultraviolet absorber is selected from any one or a combination of at least two of Tinuvin 400, Tinuvin 405 or UV-1577.

[0035] Preferably, the phenylbenzimidazole ultraviolet absorber is selected from any one or a combination of at least two of Tinuvin 328, Tinuvin360 or UV-1226.

[0036] In a second aspect, the present invention provides a method for preparing a polycarbonate coating as described in the first aspect. The method for preparing the polycarbonate coating includes the following steps:

[0037] Mix the infrared absorber, ultraviolet absorber, surfactant and composite solvent, and perform the first stirring to obtain dispersion material one.

[0038] Mix the dispersion material one and the polyhydroxyacrylic resin, perform the second stirring, and filter to obtain dispersion material two.

[0039] Mix the dispersion material two and the isocyanate curing agent, perform the third stirring to obtain the polycarbonate coating.

[0040] Preferably, the rotation speed of the first stirring is 3000 - 10000 rpm, and the time of the first stirring is 30 - 60 min.

[0041] Preferably, the rotation speed of the second stirring is 3000 - 10000 rpm, and the time of the second stirring is 30 - 60 min.

[0042] Preferably, the rotation speed of the third stirring is 300 - 1000 rpm, and the time of the third stirring is 20 - 40 min.

[0043] In a third aspect, the present invention provides an application of the polycarbonate coating as described in the first aspect or the polycarbonate coating prepared by the preparation method as described in the second aspect in the preparation of a filter device based on a polycarbonate material as a substrate.

[0044] In a fourth aspect, the present invention provides a polycarbonate sheet with an absorption layer. The polycarbonate sheet with an absorption layer includes a substrate layer and an absorption layer;

[0045] Among them, the substrate layer is a polycarbonate layer; the absorption layer is formed by thermally curing the polycarbonate coating described in the first aspect or the polycarbonate coating prepared by the preparation method described in the second aspect. The absorption layer is disposed on one side of the substrate layer, or the absorption layers are respectively disposed on both sides of the substrate layer.

[0046] In a fifth aspect, the present invention provides a method for preparing a polycarbonate sheet having an absorption layer as described in the fourth aspect. The preparation method includes the following steps:

[0047] Coat the surface of the substrate layer with the polycarbonate coating as described in the first aspect by a non-contact coating method. Without standing treatment / or after standing treatment, then thermally cure to obtain the polycarbonate sheet having an absorption layer.

[0048] Preferably, the non-contact coating method includes any one of spraying, curtain coating or slot coating.

[0049] Preferably, the coating amount of the polycarbonate coating is 10~60 mL / m 2 .

[0050] Preferably, the temperature of the thermal curing is 80~120 °C, and the time of the thermal curing is 1~10 min.

[0051] In a sixth aspect, the present invention provides a filter device, and the filter device includes a polycarbonate sheet having an absorption layer as described in the first aspect.

[0052] Preferably, the filter device further includes an anti-fouling and hardening layer, and the anti-fouling and hardening layer is disposed on the side facing the sun's incidence and is in contact with the absorption layer.

[0053] Preferably, the filter device further includes a depolarizer and a linear polarizer, and the depolarizer and the linear polarizer are sequentially connected to the side of the substrate layer away from the sun's incidence.

[0054] Preferably, when the absorption layer is disposed on one side of the substrate layer, along the direction of the sun's incidence, the filter device includes, in order, a stack of: an anti-fouling and hardening layer, an absorption layer, a substrate layer, a depolarizer and a linear polarizer; wherein, the absorption layer is formed by thermally curing the polycarbonate coating as described in the first aspect.

[0055] Preferably, when the absorption layers are disposed on both sides of the substrate layer, along the direction of the sun's incidence, the filter device includes, in order, a stack of: an anti-fouling and hardening layer, a first absorption layer, a substrate layer, a second absorption layer, a depolarizer and a linear polarizer; wherein, the absorption layer is formed by thermally curing the polycarbonate coating as described in the first aspect.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The coating for polycarbonate of the present invention solves the problems that the solvent in the coating causes large haze and easy whitening in the corrosion part of PC, PC is not resistant to UV and is prone to yellowing and powdering, and the coating has high viscosity, is prone to sagging, peeling, vertical streaks, etc.

[0058] (2) In the coating for polycarbonate of the present invention, the contents of infrared absorber and ultraviolet absorber can be maintained at a relatively high level, the transparency in the visible light region is high, and problems such as aggregation and precipitation will not occur during storage, significantly improving the heat insulation and ultraviolet resistance effects.

[0059] (3) The adhesion of the coating for polycarbonate of the present invention to the surface of polycarbonate is large in the bonding strength, and phenomena such as film layer cracking or even peeling will not occur. Description of the Drawings

[0060] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0061] Figure 1 It is a schematic structural diagram of a filter device with an absorption layer on one side of the present invention.

[0062] Among them, 1 is the substrate layer, 2 is the absorption layer, 3 is the anti-fouling and hardening layer, 4 is the depolarizer, and 5 is the linear polarizer.

[0063] Figure 2 It is a schematic structural diagram of a filter device with absorption layers on both sides of the present invention.

[0064] Among them, 1 is the substrate layer, 21 is the first absorption layer, 22 is the second absorption layer, 3 is the anti-fouling and hardening layer, 4 is the depolarizer, and 5 is the linear polarizer.

[0065] Figure 3 It is a physical diagram of the surface of a PC substrate coated with the coating for polycarbonate provided in Coating Examples 1 to 3.

[0066] Figure 4 It is a physical diagram of the surface of a PC substrate coated with the coating for polycarbonate provided in Coating Examples 4 to 5.

[0067] Figure 5 It is a physical diagram of the surface of a PC substrate coated with the coating for polycarbonate provided in Comparative Example 1. Specific Embodiments

[0068] Unless otherwise defined herein, scientific and technical terms used in connection with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meanings and scopes of the terms shall be clear. However, in any case of potential ambiguity, the definitions provided herein shall prevail over any dictionary or extrinsic definition. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "comprising" and other forms is non-restrictive.

[0069] It should be noted that specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0070] The technical solutions of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0071] In a first aspect, the present invention provides a coating for polycarbonate, and the coating for polycarbonate comprises the following components by weight parts:

[0072] 10 - 20 parts of polyhydroxy acrylic resin

[0073] 1 - 10 parts of isocyanate curing agent

[0074] 0 - 20 parts of infrared absorber

[0075] 1 - 10 parts of ultraviolet absorber

[0076] 0.1 - 5 parts of surfactant

[0077] 60 - 80 parts of composite solvent;

[0078] Wherein, the composite solvent comprises a solvent with a large molecular weight and a solvent with a small molecular weight; the molecular weight of the solvent with a large molecular weight ≥ 90 g / mol, and the molecular weight of the solvent with a small molecular weight < 90 g / mol.

[0079] As an optional implementation manner of the present invention, in the coating for polycarbonate, the content of polyhydroxy acrylic resin is 10 - 20 parts, for example, it can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.

[0080] As an optional embodiment of the present invention, in the coating for polycarbonate, the content of the isocyanate curing agent is 1 to 20 parts, for example, it can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0081] It should be noted that in the present invention, a highly transparent polyhydroxy acrylic resin - isocyanate curing resin system is selected in the coating for polycarbonate. By controlling the crosslinking reaction ratio, the formed absorption layer after curing has good adhesion and binding force on the surface of the polycarbonate material, and at the same time, it is ensured that the polycarbonate material will not be damaged during the baking and curing process; and because the polyhydroxy acrylic resin has more hydroxyl groups, it further guarantees the dispersibility with the powder absorbent, and it is stable and will not agglomerate, ensuring the storage stability.

[0082] As an optional embodiment of the present invention, in the coating for polycarbonate, the content of the infrared absorber is 0 to 20 parts, for example, it can be 0 part, 0.5 part, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc., and preferably 5 to 20 parts.

[0083] As an optional embodiment of the present invention, in the coating for polycarbonate, the content of the ultraviolet absorber is 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0084] It should be noted that under the combined action of the large - molecular - weight solvent and the small - molecular - weight solvent with specific molecular weights in the present invention, and in the way of heat - treatment curing, the coating for polycarbonate of the present invention will no longer have problems such as powder agglomeration, poor dispersibility, and easy precipitation. The addition amounts of the infrared absorber and the ultraviolet absorber can be maintained within a relatively high content range, so that the finally formed absorption layer on the surface of the polycarbonate material has a high ability to block the penetration of infrared rays and ultraviolet rays in sunlight, has good absorption and blocking effects on near - infrared rays with a relatively wide wavelength range, and further improves the heat - insulation performance, ultraviolet - resistance performance, anti - yellowing performance, weather - resistance performance, and light - transmission performance of the absorption coating.

[0085] As an optional embodiment of the present invention, in the coating for polycarbonate, the addition amount of the surfactant is 0.1 to 5 parts, for example, it can be 0.5 part, 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts, etc.

[0086] It should be noted that under the combined action of solvents with large molecular weights and solvents with small molecular weights of specific molecular weights in the present invention, there is no need for complex graft modification of infrared absorbers and ultraviolet absorbers. Only a small amount of surfactant needs to be added during the preparation process, and the emulsifying effect of the surfactant can be used to improve the compatibility of each material.

[0087] As an optional embodiment of the present invention, in the coating for polycarbonate, the content of the composite solvent is 60-80 parts, for example, it can be 60 parts, 62 parts, 64 parts, 65 parts, 66 parts, 68 parts, 70 parts, 72 parts, 74 parts, 75 parts, 78 parts, 80 parts, etc.

[0088] As an optional embodiment of the present invention, the molecular weight of the solvent with a large molecular weight is ≥90 g / mol, for example, it can be 90 g / mol, 92 g / mol, 94 g / mol, 95 g / mol, 96 g / mol, 98 g / mol, 100 g / mol, 102 g / mol, 104 g / mol, 106 g / mol, 108 g / mol, 110 g / mol, 112 g / mol, 114 g / mol, 116 g / mol, 118 g / mol, 120 g / mol, 122 g / mol, 124 g / mol, 126 g / mol, 128 g / mol, 130 g / mol, 132 g / mol, 134 g / mol, 136 g / mol, 140 g / mol, etc., and preferably 98-132 g / mol.

[0089] As an optional embodiment of the present invention, the molecular weight of the solvent with a small molecular weight is <90 g / mol, for example, it can be 89.9 g / mol, 89 g / mol, 88 g / mol, 86 g / mol, 85 g / mol, 84 g / mol, 82 g / mol, 80 g / mol, 78 g / mol, 76 g / mol, 75 g / mol, 74 g / mol, 72 g / mol, 70 g / mol, 68 g / mol, 66 g / mol, 65 g / mol, 64 g / mol, 62 g / mol, 60 g / mol, 58 g / mol, 56 g / mol, 55 g / mol, etc., and preferably 60-88 g / mol.

[0090] It should be noted that in the present invention, a composite of a solvent with a large molecular weight and a solvent with a small molecular weight having a specific molecular weight is adopted. Among them, a solvent with a large molecular weight of ≥90 g / mol is used, and such a solvent reduces the speed of the inner layer of the coating PC film. A solvent with a small molecular weight of <90 g / mol forms a solvent structure in which large molecules wrap small molecules (colloid-like structure) to weaken the erosion of small molecules on large molecules. The two cooperate with each other to have a synergistic effect, thereby solving the problems that the solvent in the coating causes a large haze and easy whitening in the part where the PC is corroded, the PC is not resistant to UV and is prone to yellowing and powdering, and the coating has a high viscosity and is prone to sagging, peeling, vertical streaks, etc.

[0091] As an optional embodiment of the present invention, the mass ratio of the solvent with a large molecular weight to the solvent with a small molecular weight is (8.5~9.8):(0.2~1.5), for example, it can be 8.5:1.5, 8.6:1.4, 8.8:1.2, 9:1, 9.2:1.8, 9.4:1.6, 9.5:0.5, 9.6:0.4, 9.8:0.2, etc.

[0092] It should be noted that in the composite solvent, the solvent with a large molecular weight and the solvent with a small molecular weight are preferably combined in the above specific mass ratio, that is, a small amount of the solvent with a small molecular weight is added to the solvent with a large molecular weight, so as to ensure that the solvent with a large molecular weight can better coat the solvent with a small molecular weight to form a more colloid-like structure, and more effectively weaken the erosion of small molecules on large molecules.

[0093] As an optional embodiment of the present invention, the solvent with a large molecular weight is selected from N any one or a combination of at least two of N-methyl-2-pyrrolidone, cyclohexanone, xylene, n-butyl acetate, propylene glycol methyl ether acetate or light aromatic solvent oil, and is preferably N any one or a combination of at least two of N-methyl-2-pyrrolidone, cyclohexanone or xylene.

[0094] It should be noted that in the composite solvent, the solvent with a large molecular weight is preferably a N heteroaromatic ketone solvent, cyclohexanone solvent and benzene ring solvent with a molecular weight of ≥90 g / mol (such as N N-methyl-2-pyrrolidone, cyclohexanone or xylene, etc.). These three solvents can better coat the solvent with a small molecular weight and can more significantly reduce the degree of corrosion of PC.

[0095] As an optional embodiment of the present invention, the solvent with a small molecular weight is selected from any one or a combination of at least two of isopropyl alcohol, butanone or ethyl acetate.

[0096] As an alternative embodiment of the present invention, the surfactant is selected from any one or a combination of at least two of alkyl sulfates with 12 or more carbon atoms, linear alcohol polyoxyethylene ether sulfates, sulfated triglycerides, polyoxyethylene alkylphenols, linear alcohol polyoxyethylene ethers, polyether-modified polydimethylsiloxanes, or polyureas.

[0097] As an alternative embodiment of the present invention, the hydroxyl value of the polyhydroxy acrylic resin is 10 to 150 mgKOH / g, and for example, it can be 10 mgKOH / g, 20 mgKOH / g, 30 mgKOH / g, 40 mgKOH / g, 50 mgKOH / g, 60 mgKOH / g, 70 mgKOH / g, 80 mgKOH / g, 90 mgKOH / g, 100 mgKOH / g, 110 mgKOH / g, 120 mgKOH / g, 130 mgKOH / g, 140 mgKOH / g, 150 mgKOH / g, etc.

[0098] As an alternative embodiment of the present invention, the polyhydroxy acrylic resin is selected from any one or a combination of at least two of HU840K from Laiyang Hong'an, HA865 from Kunshan Kaster, LR7601 from Mitsubishi, or DS-2055 resin from Nantong Baisen Chemical Industry.

[0099] It should be noted that as described above, the resin used in the present invention is a highly transparent polyhydroxy acrylic resin. Since the coated substrate is made of PC material with a Tg point of 140 degrees, it is necessary to select a polyhydroxy acrylic resin with a medium to low hydroxyl value (10 to 150 mgKOH / g) to prevent damage to the PC material during the baking and curing process.

[0100] As an alternative embodiment of the present invention, the isocyanate curing agent is selected from hexamethylene diisocyanate and / or isophorone diisocyanate.

[0101] As an alternative embodiment of the present invention, the isocyanate curing agent is selected from any one or a combination of at least two of N3300 of the HDI type from BASF, XP 2400 of the IPDI type from BASF, HDI 200 from Wanhua, IPDI 200 from Wanhua, L75 of the HDI type from Covestro, or I100 of the IPDI type from Covestro.

[0102] It should be noted that considering the strict aging performance and optical performance requirements for automotive applications, the curing system of hexamethylene diisocyanate and / or isophorone diisocyanate as described above is selected.

[0103] As an alternative embodiment of the present invention, the infrared absorber includes organic dyes and metal oxides.

[0104] As an alternative embodiment of the present invention, the mass ratio of the organic dye to the metal oxide is (0.05~2):(8~10);

[0105] Among them, "0.05~2" can be, for example, 0.05, 0.08, 0.1, 0.2, 0.4, 0.5, 0.6, 0.8, 1, 1.2, 1.4, 1.5, 1.6, 1.8, 2, etc.;

[0106] Among them, "8~10" can be, for example, 8, 8.2, 8.4, 8.5, 8.6, 8.8, 9, 9.2, 9.4, 9.6, 9.8, 10, etc.

[0107] As an alternative embodiment of the present invention, the organic dye is selected from indole-based near-infrared fluorescent organic dyes.

[0108] As an alternative embodiment of the present invention, the organic dye is selected from any one or a combination of at least two of IR780, IR820, IR956, IR1008 or IR1086.

[0109] As an alternative embodiment of the present invention, the metal oxide is selected from nano rare earth metal oxide powders, and the particle size of the nano rare earth metal oxide powders is 20~50 nm, for example, it can be 20 nm, 25 nm, 30 nm, 35 nm, 40nm, 45 nm, 50 nm, etc., and the specific surface area of the nano rare earth metal oxide powders is 30~60 m 2 / g, for example, it can be 30 m 2 / g, 35 m 2 / g, 40 m 2 / g, 45 m 2 / g, 50 m 2 / g, 55 m 2 / g, 60 m 2 / g, etc.

[0110] As an alternative embodiment of the present invention, the metal oxide is selected from any one or a combination of at least two of tungsten oxide, tungsten cesium oxide, tungsten gold vanadium oxide, tungsten vanadium tin antimony oxide, cesium tungsten bronze.

[0111] It should be noted that in the technical solution of the present invention as described above, it is preferably to use a composite of indole-based near-infrared fluorescent organic dye and nano rare earth metal oxide powder in a specific ratio as the infrared absorber. The two are combined with each other and have a synergistic effect, which significantly improves the absorption and blocking effect on near-infrared rays with a relatively wide wavelength, and further improves the heat insulation performance and light transmittance of the thermosetting coating.

[0112] As an alternative embodiment of the present invention, the ultraviolet absorber is selected from any one or a combination of at least two of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, or phenylbenzimidazole ultraviolet absorbers.

[0113] As an alternative embodiment of the present invention, the benzotriazole ultraviolet absorber is selected from any one or a combination of at least two of UV326, UV327, UV329, or UVP.

[0114] As an alternative embodiment of the present invention, the triazine ultraviolet absorber is selected from any one or a combination of at least two of Tinuvin 400, Tinuvin 405, or UV-1577.

[0115] As an alternative embodiment of the present invention, the phenylbenzimidazole ultraviolet absorber is selected from any one or a combination of at least two of Tinuvin 328, Tinuvin360, or UV-1226.

[0116] In a second aspect, the present invention provides a method for preparing a coating for polycarbonate as described in the first aspect. The method for preparing the coating for polycarbonate includes the following steps:

[0117] Mix the infrared absorber, ultraviolet absorber, surfactant, and composite solvent, and perform a first stirring to obtain a first dispersion material.

[0118] Mix the first dispersion material and the polyhydroxy acrylic resin, perform a second stirring, and filter to obtain a second dispersion material.

[0119] Mix the second dispersion material and the isocyanate curing agent, and perform a third stirring to obtain the coating for polycarbonate.

[0120] As an alternative embodiment of the present invention, the rotation speed of the first stirring is 3000 - 10000 rpm, for example, it can be 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm, etc. The time of the first stirring is 30 - 60 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0121] As an alternative embodiment of the present invention, the rotational speed of the second stirring is 3000 - 10000 rpm, for example, it can be 3000 rpm, 4000 rpm, 5000 rpm, 6000 rpm, 7000 rpm, 8000 rpm, 9000 rpm, 10000 rpm, etc., and the time of the second stirring is 30 - 60 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc.

[0122] As an alternative embodiment of the present invention, the rotational speed of the third stirring is 300 - 1000 rpm, for example, it can be 300 rpm, 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm, 9000 rpm, 1000 rpm, etc., and the time of the third stirring is 20 - 40 min, for example, it can be 20 min, 25 min, 30 min, 35 min, 40 min, etc.

[0123] In a third aspect, the present invention provides an application of the polycarbonate coating as described in the first aspect or the polycarbonate coating prepared by the preparation method as described in the second aspect in the preparation of a filter device based on a polycarbonate material.

[0124] In a fourth aspect, the present invention provides a polycarbonate sheet with an absorption layer, and the polycarbonate sheet with an absorption layer includes a substrate layer and an absorption layer.

[0125] As an alternative embodiment of the present invention, the substrate layer is a polycarbonate layer.

[0126] As an alternative embodiment of the present invention, the absorption layer is formed by heat curing the polycarbonate coating as described in the first aspect or the polycarbonate coating prepared by the preparation method as described in the second aspect, and the absorption layer is disposed on one side of the substrate layer.

[0127] As an alternative embodiment of the present invention, the absorption layer is formed by heat curing the polycarbonate coating as described in the first aspect or the polycarbonate coating prepared by the preparation method as described in the second aspect, and the absorption layer is disposed on both sides of the substrate layer respectively.

[0128] In a fifth aspect, the present invention provides a preparation method of a polycarbonate sheet with an absorption layer as described in the fourth aspect, and the preparation method includes the following steps:

[0129] The polycarbonate coating material as described in the first aspect is applied to the surface of the substrate layer by a non-contact coating method. Without standing treatment / or after standing treatment, it is then heat-treated and cured to obtain the polycarbonate sheet with an absorption layer.

[0130] As an optional embodiment of the present invention, the non-contact coating method includes any one of spraying, curtain coating, or slot coating.

[0131] It should be noted that in the present invention, a suitable coating method is selected, that is, a non-contact coating method is adopted, such as the above-mentioned spraying, curtain coating, slot coating, etc., to avoid contact coating, such as microgravure and knife coating, which may cause scratches on the surface in the case of solvent-swollen surface.

[0132] As an optional embodiment of the present invention, the coating amount of the polycarbonate coating material is 10 - 60 mL / m 2 , for example, it can be 10 mL / m 2 , 14 mL / m 2 , 16 mL / m 2 , 18 mL / m 2 , 20 mL / m 2 , 24 mL / m 2 , 28 mL / m 2 , 32 mL / m 2 , 36mL / m 2 , 40 mL / m 2 , 45 mL / m 2 , 50 mL / m 2 , 55 mL / m 2 , 60 mL / m 2 and so on.

[0133] As an optional embodiment of the present invention, the time of the standing treatment is 30 s - 2 min, for example, it can be 30 s, 40 s, 50 s, 1 min, 1.2 min, 1.4 min, 1.5 min, 1.6 min, 1.8 min, 2 min, etc.

[0134] As an optional embodiment of the present invention, the temperature of the heat treatment and curing is 80 - 120 °C, for example, it can be 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, etc., and the time of the heat treatment and curing is 1 - 10 min, for example, it can be 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, etc.

[0135] Sixth aspect, the present invention provides a filter device, and the filter device includes a polycarbonate sheet having an absorption layer as described in the first aspect.

[0136] As an optional embodiment of the present invention, the filter device further includes an anti-fouling and hardening layer, and the anti-fouling and hardening layer is disposed on the side facing the sun incidence and is in contact with the absorption layer.

[0137] As an optional embodiment of the present invention, the anti-fouling and hardening layer includes, by weight: 1 to 3 parts of a high bond energy material and 1 to 2 parts of a multi-crosslinked end point material.

[0138] As an optional embodiment of the present invention, the content of the high bond energy material in the hardening layer is 1 to 3 parts, for example, it can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, 2.2 parts, 2.4 parts, 2.6 parts, 2.8 parts, 3 parts, etc.

[0139] As an optional embodiment of the present invention, the content of the multi-crosslinked end point material in the hardening layer is 1 to 2 parts, for example, it can be 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, 2 parts, etc.

[0140] As an optional embodiment of the present invention, the high bond energy material is selected from any one or a combination of at least two of IBOA, GMA, POEA or THFA.

[0141] As an optional embodiment of the present invention, the multi-crosslinked end point material is selected from any one or a combination of at least two of TMPTA, PETA, DPPA or DHPA.

[0142] As an optional embodiment of the present invention, the thickness of the hardening layer is 3 to 6 μm, for example, it can be 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm, 6 μm, etc.

[0143] As an optional embodiment of the present invention, the filter device further includes a depolarizer and a linear polarizer, and the depolarizer and the linear polarizer are sequentially connected to the side of the substrate layer away from the sun incidence.

[0144] It should be noted that, in the present invention, the filter device further includes a depolarizer and a linear polarizer. The side of the substrate layer away from the sun incidence is sequentially connected to the depolarizer and the linear polarizer. That is, first, the sunlight is subjected to ultraviolet light absorption and infrared light absorption, which can reduce more than half of the radiation energy, and then it freely passes through the depolarizer without any light loss. Finally, the linear polarizer intercepts half of the polarized light, further reducing the radiation energy of the sunlight. In the projection direction, the projection polarized light freely passes through the linearly polarized light sheets distributed in the same direction, and then the projection polarized light is depolarized by the depolarizer and then passes through the absorption layer. Since ultraviolet light and infrared light are not visible light, it has no impact on human eye observation. On the contrary, the absorption of ultraviolet light protects the eyes of the user. Then, the depolarized projection polarized light passes through the hardening layer and the anti-fouling layer without loss.

[0145] As an optional implementation manner of the present invention, as Figure 1 shown, when the absorption layer is disposed on one side of the substrate layer, along the sun incidence direction, the filter device includes, in sequence from bottom to top: an anti-fouling hardening layer 3, an absorption layer 2, a substrate layer 1, a depolarizer 4, and a linear polarizer 5; wherein, the absorption layer 2 is formed by thermally curing the polycarbonate coating as described in the first aspect.

[0146] As an optional implementation manner of the present invention, as Figure 2 shown, when the absorption layer is disposed on both sides of the substrate layer, along the sun incidence direction, the filter device includes, in sequence from bottom to top: an anti-fouling hardening layer 3, a first absorption layer 21, a substrate layer 1, a second absorption layer 22, a depolarizer 4, and a linear polarizer 5; wherein, the first absorption layer 21 and the second absorption layer 22 are formed by thermally curing the polycarbonate coating as described in the first aspect.

[0147] The present invention will be further described below through examples. Unless otherwise specified, the materials in the examples are prepared according to existing methods or directly purchased from the market.

[0148] Example 1

[0149] This example provides a polycarbonate coating and a high-transparency polycarbonate sheet with an anti-UV aging absorption layer prepared therefrom. As shown in Table 1 below, the polycarbonate coating includes the following components by weight:

[0150] Table 1

[0151]

[0152] The polycarbonate sheet with an absorption layer is prepared by the following steps:

[0153] S1. Preparation of the polycarbonate coating:

[0154] First, mix the infrared absorber, ultraviolet absorber, surfactant and composite solvent according to the above ratio, stir at a speed of 10,000 rpm for 40 min to obtain Dispersion Material 1; then add polyhydroxy acrylic resin to Dispersion Material 1, stir at a speed of 10,000 rpm for 40 min, filter with a 50 nm filter element (Hangzhou Cobetter), and then add isocyanate curing agent, stir at a speed of 500 rpm for 30 min to obtain the coating for polycarbonate.

[0155] S2. Preparation of polycarbonate sheet with absorption layer:

[0156] Coat the coating for polycarbonate obtained in S1 on one side of the polycarbonate sheet by spraying, with a coating amount of 40 mL / m 2 , leave it to stand on the PC surface at room temperature for 1 min, then send it to an oven and bake at 80 °C for 10 min to complete curing, and form an absorption layer on one side of the polycarbonate sheet substrate.

[0157] Example 2

[0158] This example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. As shown in Table 2 below, the coating for polycarbonate includes the following components by weight:

[0159] Table 2

[0160]

[0161] The polycarbonate sheet with an absorption layer is prepared by the following steps:

[0162] S1. Preparation of coating for polycarbonate:

[0163] First, mix the infrared absorber, ultraviolet absorber, surfactant and composite solvent according to the above ratio, stir at a speed of 10,000 rpm for 40 min to obtain Dispersion Material 1; then add polyhydroxy acrylic resin to Dispersion Material 1, stir at a speed of 10,000 rpm for 40 min, filter with a 50 nm filter element (Hangzhou Cobetter), and then add isocyanate curing agent, stir at a speed of 500 rpm for 30 min to obtain the coating for polycarbonate.

[0164] S2. Preparation of polycarbonate sheet with absorption layer:

[0165] Coat the coating for polycarbonate obtained in S1 on one side of the polycarbonate sheet by spraying, with a coating amount of 40 mL / m 2, after standing on the PC surface at room temperature for 1 min, it is sent to an oven and baked at 80 °C for 10 min to complete curing, and an absorption layer is formed on one side of the polycarbonate sheet substrate.

[0166] Example 3

[0167] This example provides a polycarbonate coating and a polycarbonate sheet with an absorption layer prepared therefrom. As shown in Table 3 below, the polycarbonate coating includes the following components by weight:

[0168] Table 3

[0169]

[0170] The polycarbonate sheet with an absorption layer is prepared by the following steps:

[0171] S1. Preparation of the polycarbonate coating:

[0172] First, mix the infrared absorber, ultraviolet absorber, surfactant and composite solvent according to the above ratio, stir at a speed of 10000 rpm for 40 min to obtain dispersion material 1; then add polyhydroxy acrylic resin to dispersion material 1, stir at a speed of 10000 rpm for 40 min, filter with a 50 nm filter element (Hangzhou KeBaiTe), and then add isocyanate curing agent, stir at a speed of 500 rpm for 30 min to obtain the polycarbonate coating.

[0173] S2. Preparation of the polycarbonate sheet with an absorption layer:

[0174] Coat the polycarbonate coating obtained in S1 on one side of the polycarbonate sheet by spraying, and the coating amount is 40 mL / m 2 , after standing on the PC surface at room temperature for 1 min, it is sent to an oven and baked at 80 °C for 10 min to complete curing, and an absorption layer is formed on one side of the polycarbonate sheet substrate.

[0175] Example 4

[0176] This example provides a polycarbonate coating and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that: in S2, after coating the polycarbonate coating obtained in S1 on one side of the polycarbonate sheet by spraying, it is not allowed to stand, and is directly sent to an oven and baked at 120 °C for 10 min to complete curing. Other steps are exactly the same as those in Example 1, and an absorption layer is formed on one side of the polycarbonate sheet substrate.

[0177] Example 5

[0178] This embodiment provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 4 is only that: in S2, the coating for polycarbonate obtained in S1 is applied to both sides of the polycarbonate sheet by spraying, and the coating amount on both sides is 20 mL / m 2 , that is, a first absorption layer is formed on one side of the polycarbonate sheet substrate, and a second absorption layer is formed on the other side. Other steps are exactly the same as those in Example 4.

[0179] Example 6

[0180] This embodiment provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. As shown in Table 4 below, the coating for polycarbonate includes the following components by weight:

[0181] Table 4

[0182]

[0183] The polycarbonate sheet with an absorption layer is prepared by the following steps:

[0184] S1. Preparation of the coating for polycarbonate:

[0185] First, the infrared absorber, ultraviolet absorber, surfactant and composite solvent are mixed according to the above ratio, and stirred at a speed of 10000 rpm for 40 min to obtain Dispersion Material 1; then polyhydroxy acrylic resin is added to Dispersion Material 1, stirred at a speed of 10000 rpm for 40 min, filtered with a 50 nm filter element (Hangzhou Cobetter), and then isocyanate curing agent is added, and stirred at a speed of 500 rpm for 30 min to obtain the coating for polycarbonate.

[0186] S2. Preparation of the polycarbonate sheet with an absorption layer:

[0187] The coating for polycarbonate obtained in S1 is applied to both sides of the polycarbonate sheet by spraying, and the coating amount on both sides is 20 mL / m 2 , and directly sent to an oven for baking at 120 °C for 10 min to complete curing, that is, a first absorption layer is formed on one side of the polycarbonate sheet substrate, and a second absorption layer is formed on the other side.

[0188] Example 7

[0189] This embodiment provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. As shown in Table 5 below, the coating for polycarbonate includes the following components by weight:

[0190] Table 5

[0191]

[0192] The polycarbonate sheet with an absorption layer is prepared by the following steps:

[0193] S1. Preparation of the polycarbonate coating:

[0194] First, mix the infrared absorber, ultraviolet absorber, surfactant, and composite solvent according to the above ratio, stir at a speed of 10000 rpm for 40 min to obtain Dispersion Material 1; then add polyhydroxyacrylic resin to Dispersion Material 1, stir at a speed of 10000 rpm for 40 min, filter using a 50 nm filter element (Hangzhou KeBaiTe), and then add isocyanate curing agent, stir at a speed of 500 rpm for 30 min to obtain the polycarbonate coating.

[0195] S2. Preparation of the polycarbonate sheet with an absorption layer:

[0196] Coat the polycarbonate coating obtained in S1 on both sides of the polycarbonate sheet by spraying, with the coating amount on both sides being 20 mL / m 2 , directly send it into an oven and bake at 120 °C for 10 min to complete curing, that is, form a first absorption layer on one side of the polycarbonate sheet substrate and a second absorption layer on the other side.

[0197] Example 8

[0198] This example provides a polycarbonate coating and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that N N-methyl-2-pyrrolidone is replaced with cyclohexanone of equal weight, and ethyl acetate is replaced with methyl formate of equal weight, and other steps are completely the same as those in Example 1.

[0199] Example 9

[0200] This example provides a polycarbonate coating and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that N N-methyl-2-pyrrolidone is replaced with xylene of equal weight, and other steps are completely the same as those in Example 1.

[0201] Example 10

[0202] This example provides a polycarbonate coating and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that N N-methyl-2-pyrrolidone is replaced with xylene of equal weight, and ethyl acetate is replaced with isopropanol of equal weight, and other steps are completely the same as those in Example 1.

[0203] Example 11

[0204] This example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that N- the content of N-methyl-2-pyrrolidone is adjusted to 50 parts, and the content of ethyl acetate is adjusted to 20 parts. Other steps are exactly the same as those in Example 1.

[0205] Example 12

[0206] This example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that N- the content of N-methyl-2-pyrrolidone is adjusted to 69.5 parts, and the content of ethyl acetate is adjusted to 0.5 part. Other steps are exactly the same as those in Example 1.

[0207] Comparative Example 1

[0208] This comparative example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that no N- N-methyl-2-pyrrolidone is added, and the content of ethyl acetate is adjusted to 70 parts. Other steps are exactly the same as those in Example 1.

[0209] Comparative Example 2

[0210] This comparative example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that no ethyl acetate is added, N- and the content of N-methyl-2-pyrrolidone is adjusted to 70 parts. Other steps are exactly the same as those in Example 1.

[0211] Comparative Example 3

[0212] This comparative example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that the composite solvent is 68 parts of ethyl acetate and 2 parts of butanone. Other steps are exactly the same as those in Example 1.

[0213] Comparative Example 4

[0214] This comparative example provides a coating for polycarbonate and a polycarbonate sheet with an absorption layer prepared therefrom. The difference from Example 1 is only that the composite solvent is 68 parts of N N-methyl-2-pyrrolidone and 2 parts of cyclohexanone. Other steps are exactly the same as those in Example 1.

[0215] Test Example 1

[0216] Test samples: Polycarbonate sheets with an absorption layer provided in Examples 1 to 12, and polycarbonate sheets with an absorption layer provided in Comparative Examples 1 to 4.

[0217] Test method: Test with a HAM200 haze meter from afar.

[0218] The specific test results are shown in Table 6, and Figure 3 、 Figure 4 and Figure 5 as shown ( " / " indicates that the coating is insoluble or hardly soluble during the mixing process):

[0219] Table 6

[0220]

[0221] As shown in Table 6, the haze of the present invention can be as low as below 2%, indicating that in the present invention, a composite of a large-molecular-weight solvent and a small-molecular-weight solvent with a specific molecular weight is adopted. Among them, a solvent with a molecular weight ≥ 90 g / mol is used to reduce the speed of the inner layer of the coating PC film, and a solvent with a molecular weight < 90 g / mol is used to form a solvent structure in which macromolecules wrap small molecules (colloid-like structure) to weaken the erosion of small molecules on macromolecules. The two cooperate with each other to have a synergistic effect, thus solving the problems of high haze and easy whitening of the part corroded by the solvent in the coating on the PC.

[0222] It can be seen from the comparison between Example 1 and Examples 4 to 7 that after coating the polycarbonate described in S1 on one side of the polycarbonate sheet and not standing still, it is directly sent to an oven for baking at a high temperature to complete curing, which can further reduce the haze of the polycarbonate sheet.

[0223] It can be seen from the comparison between Example 1 and Example 8 that although there is the wrapping effect of the large-molecular-weight solvent cyclohexanone, methyl formate is more corrosive to the polycarbonate sheet than ethyl acetate. Therefore, the haze of the polycarbonate sheet provided in Example 8 is higher.

[0224] It can be seen from the comparison between Example 1 and Example 9 that N N-methyl-2-pyrrolidone and xylene can both form a solvent structure in which macromolecules wrap small molecules (colloid-like structure) to weaken the erosion of ethyl acetate on macromolecules. Therefore, the haze of the two is close.

[0225] It can be seen from the comparison between Example 1, Examples 4 to 7 and Example 10 that the small-molecular-weight solvent isopropyl alcohol has less erosion on the polycarbonate sheet. Even without direct baking, its haze can still be reduced to below 0.35%.

[0226] Test Example 2

[0227] Test samples: Polycarbonate sheets with an absorption layer provided in Examples 1 to 12, and polycarbonate sheets with an absorption layer provided in Comparative Examples 1 to 4.

[0228] Test method: Shimadzu UV1900 spectrophotometer.

[0229] Specific test results are shown in Table 7 ( " / " indicates that the coating is insoluble or hardly soluble during mixing):

[0230] Table 7

[0231]

[0232] As shown in Table 7, under the combined action of a solvent with a large molecular weight and a solvent with a small molecular weight of a specific molecular weight in the present invention, the addition amounts of the infrared absorber and the ultraviolet absorber can be maintained within a relatively high content range, so that the absorption layer finally formed on the surface of the polycarbonate material has a high ability to block the penetration of infrared rays and ultraviolet rays in sunlight, and has a good absorption and blocking effect on near-infrared rays of a relatively wide wavelength.

[0233] From the comparison between Example 1 and Examples 2 to 3, it can be seen that in Example 1, no infrared absorber is added, and its average visible light transmittance is high and there is no absorption of infrared light, so the heat insulation performance is poor; while in Examples 2 to 3, a certain proportion of infrared light absorber is added, and its average visible light transmittance and average infrared light transmittance are significantly reduced, so the heat insulation performance can be significantly improved.

[0234] Test Example 3

[0235] Test samples: Polycarbonate sheets with an absorption layer provided in Examples 1 to 12, and polycarbonate sheets with an absorption layer provided in Comparative Examples 1 and 3.

[0236] Test method:

[0237] (1) Interlayer bonding strength: Bake in an oven at 120 °C for 48 h, and use the paint film test standard of GB / T 9286-2021;

[0238] (2) Anti-cracking situation: Apply two-component epoxy glue on the LED display unit board, cure at room temperature for 48 h, and then put it into an oven at 100 °C for baking for 0.5 h to achieve the effect of complete curing and elimination of thermal stress. Conduct thermal shock tests on the unit board, and the test conditions are: -40 °C / 120 °C, 1 h per round, for a total of 100 rounds.

[0239] (3) Damp heat aging performance: The damp heat aging performance test is carried out under the conditions of a temperature of 85 °C and a relative humidity of 85% for 2000 h, and the yellowing value of the paint film is used to characterize its damp heat aging performance.

[0240] (4) UV aging yellowing value: Tested under a UV lamp (wavelength 300 - 380 nm), after the irradiation dose reaches 200 kWh / m 2 ², the yellowing value of the coating film is used to characterize its damp heat aging performance.

[0241] The specific test results are shown in Table 8 ( / represents insoluble or hardly soluble):

[0242] Table 8

[0243]

[0244] As shown in Table 8, under the combined action of the large - molecular - weight solvent and the small - molecular - weight solvent with specific molecular weights in the present invention, and by means of heat - treatment curing, the coating for polycarbonate of the present invention no longer has problems such as powder agglomeration, poor dispersibility, and easy precipitation, further improving the heat - insulation performance, anti - ultraviolet performance, anti - yellowing performance, weather resistance performance, and light - transmission performance of the absorption coating.

[0245] Application Example 1

[0246] This application example provides a filter device. Along the direction of solar incidence, the filter device includes, stacked in sequence: an anti - stain hardening layer, a polycarbonate sheet with an absorption layer provided in Example 1, a depolarizer, and a linear polarizer.

[0247] Among them, the anti - stain hardening layer includes, by weight: 3 parts of a high - bond - energy material and 1 part of a multi - cross - linked end - point material. The high - bond - energy material is IOBA, the multi - cross - linked end - point material is TMPTA, and the thickness of the hardening layer is 4.5 μm. Among them, the depolarizer is a quarter - wave plate (provided by Zhejiang Yitaiji); among them, the linear polarizer is a dichroic polarizer (Sunny Optronics, Foshan Weida, etc.).

[0248] Application Example 2

[0249] This application example provides a filter device, which is only different from Application Example 1 in that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 2, and other parameters are exactly the same as those in Example 1.

[0250] Application Example 3

[0251] This application example provides a filter device, which is only different from Application Example 1 in that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 3, and other parameters are exactly the same as those in Example 1.

[0252] Application Example 4

[0253] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 4, and other parameters are exactly the same as those in Example 1.

[0254] Application Example 5

[0255] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 5, and other parameters are exactly the same as those in Example 1.

[0256] Application Example 6

[0257] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 6, and other parameters are exactly the same as those in Example 1.

[0258] Application Example 7

[0259] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 7, and other parameters are exactly the same as those in Example 1.

[0260] Application Example 8

[0261] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 8, and other parameters are exactly the same as those in Example 1.

[0262] Application Example 9

[0263] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 9, and other parameters are exactly the same as those in Example 1.

[0264] Application Example 10

[0265] This application example provides a filter device. The difference from Application Example 1 is only that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 10, and other parameters are exactly the same as those in Example 1.

[0266] Application Example 11

[0267] This application example provides a filter device, which is only different from Application Example 1 in that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 11, and other parameters are exactly the same as those in Example 1.

[0268] Application Example 12

[0269] This application example provides a filter device, which is only different from Application Example 1 in that the polycarbonate sheet with an absorption layer provided in Example 1 is replaced with the polycarbonate sheet with an absorption layer provided in Example 12, and other parameters are exactly the same as those in Example 1.

[0270] Test Example 4

[0271] Test samples: The filter devices provided in Application Examples 1 to 12.

[0272] Test method:

[0273] (1) Transmittance and haze: Measured by the ASTM D1003 method on a transmittance and haze meter.

[0274] (2) Hardness test: Tested by the ASTM D3363 method.

[0275] (3) Anti-fouling test: Coated with an oil-based pen, wiped off after 5 minutes and repeated 50 times. No residual trace after wiping is considered non-fouled, a faint residual trace after wiping is considered slightly fouled, and an obvious residual trace after wiping is considered severely fouled.

[0276] (4) UV aging test: Using a QUVA aging instrument, one aging test lasts for 96 h, which includes 12 cycles of 8 h. One cycle includes 4 h of UV exposure (UV-A, 340 nm, 0.63 W / m 2 , 60 °C) and 4 h of humidity exposure (50 °C); then observe. No cracks, delamination, warping, color change and other defects are considered qualified, otherwise unqualified.

[0277] The specific test results are shown in Table 9:

[0278] Table 9

[0279]

[0280] As shown in Table 9, the filter device of the present invention can prevent the product from being accidentally scratched and damaged. This product includes an absorption layer, which can absorb ultraviolet light and infrared light, achieving the effect of greatly reducing the radiation energy of ultraviolet light and infrared light, thereby realizing anti-ultraviolet yellowing. The HUD protective cover made of this product can reduce the risk of the HUD projection device being burned by sunlight, meeting people's usage requirements.

[0281] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a polycarbonate sheet having an absorption layer, characterized in that, The preparation method includes: Coating the polycarbonate with a coating material on the surface of the substrate layer by a non-contact coating method, without standing treatment, and curing by heat treatment to obtain the polycarbonate sheet with an absorption layer; wherein, the temperature of the heat treatment curing is 80-120°C, and the time of the heat treatment curing is 1-10 min; The coating material for polycarbonate includes the following components by weight: 10-20 parts of polyhydroxy acrylic resin 1-10 parts of isocyanate curing agent 0-20 parts of infrared absorber 1-10 parts of ultraviolet absorber 0.1-5 parts of surfactant 60-80 parts of composite solvent; Among them, the composite solvent is composed of a solvent with a large molecular weight and a solvent with a small molecular weight; the mass ratio of the solvent with a large molecular weight to the solvent with a small molecular weight is (8.5 to 9.8):(0.2 to 1.5); the solvent with a large molecular weight is selected from N -methyl-2-pyrrolidone; the solvent with a small molecular weight is selected from ethyl acetate; Wherein, the surfactant is selected from any one or at least two combinations of alkyl sulfates with 12 or more carbon atoms, linear alcohol polyoxyethylene ether sulfates, sulfated triglycerides, polyoxyethylene alkyl phenols or linear alcohol polyoxyethylene ethers.

2. The method for preparing a polycarbonate sheet having an absorption layer according to claim 1, characterized in that, The hydroxyl value of the polyhydroxy acrylic resin is 10-150 mgKOH / g; And / or, the isocyanate curing agent is selected from hexamethylene diisocyanate and / or isophorone diisocyanate.

3. The method for preparing a polycarbonate sheet having an absorption layer according to claim 1, characterized in that, The infrared absorber includes organic dyes and metal oxides; And / or, the mass ratio of the organic dyes to the metal oxides is (0.05-2):(8-10); And / or, the organic dyes are selected from indole-based near-infrared fluorescent organic dyes; And / or, the organic dyes are selected from any one or at least two combinations of IR780, IR820, IR956, IR1008 or IR1086; And / or, the metal oxide is selected from nano rare earth metal oxide powder, the particle size of the nano rare earth metal oxide powder is 20-50 nm, and the specific surface area of the nano rare earth metal oxide powder is 30-60 m 2 / g; And / or, the metal oxides are selected from any one or at least two combinations of tungsten oxide, tungsten cesium oxide, tungsten gold vanadium oxide, tungsten vanadium tin antimony oxide, cesium tungsten bronze; And / or, the ultraviolet absorber is selected from any one or at least two combinations of benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers or phenylbenzimidazole ultraviolet absorbers; And / or, the benzotriazole ultraviolet absorbers are selected from any one or at least two combinations of UV326, UV327, UV329 or UVP; And / or, the triazine ultraviolet absorbers are selected from any one or at least two combinations of Tinuvin 400, Tinuvin 405 or UV-1577; And / or, the phenylbenzimidazole ultraviolet absorbers are selected from any one or at least two combinations of Tinuvin 328, Tinuvin360 or UV-1226.

4. The method for preparing a polycarbonate sheet having an absorption layer according to claim 1, characterized in that, The preparation method of the coating material for polycarbonate includes the following steps: Mixing the infrared absorber, ultraviolet absorber, surfactant and composite solvent, and carrying out the first stirring to obtain dispersion material one; Mixing the dispersion material one and polyhydroxy acrylic resin, carrying out the second stirring, and filtering to obtain dispersion material two; Mixing the dispersion material two and isocyanate curing agent, and carrying out the third stirring to obtain the coating material for polycarbonate; And / or, the rotation speed of the first stirring is 3000-10000 rpm, and the time of the first stirring is 30-60 min; And / or, the rotation speed of the second stirring is 3000 - 10000 rpm, and the time of the second stirring is 30 - 60 min; And / or, the rotation speed of the third stirring is 300 - 1000 rpm, and the time of the third stirring is 20 - 40 min.

5. The method for preparing a polycarbonate sheet having an absorption layer according to claim 1, characterized in that, The non-contact coating method includes any one of spraying, curtain coating or slot coating; And / or, the coating amount of the polycarbonate coating is 10~60 mL / m 2 .

6. A polycarbonate sheet having an absorption layer, characterized in that, The polycarbonate sheet with an absorption layer is prepared by the preparation method of the polycarbonate sheet with an absorption layer according to any one of claims 1 - 5; The polycarbonate sheet with an absorption layer includes a substrate layer and an absorption layer; wherein, the substrate layer is a polycarbonate layer; the absorption layer is formed by thermosetting the polycarbonate with a coating, and the absorption layer is disposed on one side of the substrate layer, or the absorption layers are respectively disposed on both sides of the substrate layer.

7. A filter device, characterized in that, The filter device includes the polycarbonate sheet with an absorption layer according to claim 6; And / or, the filter device further includes an anti-fouling and hardening layer, which is disposed on the side facing the sun incidence and is in contact with the absorption layer; And / or, the filter device further includes a depolarizer and a linear polarizer, and the depolarizer and the linear polarizer are sequentially connected to the side of the substrate layer away from the sun incidence.

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