A method for preparing high-performance 3D photonic crystal structured color coatings

Abstract

This invention discloses a method for preparing a high-performance 3D photonic crystal structured color coating. The high-performance 3D photonic crystal structured color coating comprises 1-30 parts by weight of hard 3D photonic crystal pigment, 5-45 parts by weight of reactive monomer diluent, 50-80 parts by weight of ultraviolet (UV) light-curing resin, and 1-5 parts by weight of photoinitiator. During the preparation process, the 3D photonic crystal pigment, reactive monomer diluent, UV light-curing resin, and photoinitiator are thoroughly mixed at room temperature, wherein the 3D photonic crystal pigment is uniformly dispersed in the UV light-curing resin. The photonic crystal pigment is obtained by crushing a hard photonic crystal film at room temperature, and the hard photonic crystal film is prepared using a shell softener as a mediated method. The resulting 3D photonic crystal structured color coating can provide durable, stable, and vibrant colors to decorative materials through various methods such as spraying, brushing, scraping, or dipping.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically, it relates to a method for preparing a high-performance 3D photonic crystal structure color coating. Background Technology

[0002] In recent years, with the continuous improvement of environmental protection standards and the deepening of research on functional materials, structural color materials have gradually become a research hotspot in fields such as coating, decoration, and anti-counterfeiting due to their unique optical color rendering effect, lightfastness, and long-term stability. Traditional dyes and pigments are easily affected by the environment and fade, making it difficult to meet the demand for long-lasting and vibrant colors in high-end decorative materials. In contrast, structural color materials based on the photonic crystal effect regulate light propagation through periodic structures at the micro-nano scale, thereby achieving high brightness, saturation, and stable color display, exhibiting significant green and environmentally friendly advantages.

[0003] Current research on 3D photonic crystal structural color coatings mainly focuses on the synthesis mechanism, structural control, and exploration of their optical properties (CN 110079171A). Most existing technologies first employ high-temperature, long-time curing or multi-step processes to prepare 3D photonic crystal materials with ideal photonic bandgap effects, then freeze-crush the photonic crystal materials under liquid nitrogen. This not only increases process complexity and production costs but also places high demands on the production environment. Simultaneously, achieving efficient and uniform dispersion of photonic crystal pigments in the matrix material (UV-curable resin) during the preparation of structural color coatings is crucial to ensuring the optical performance and application stability of the final product. However, existing preparation processes struggle to achieve both uniform pigment dispersion and structural stability at room temperature, often resulting in pigment agglomeration, structural damage, difficulty in controlling mesh size, and challenges in achieving effective bonding with the resin matrix. This leads to microcracks at the interface between the structural color pigment and the resin, making the coating prone to delamination, cracking, and fading under long-term use or complex environmental conditions. Furthermore, in practical applications, especially during processes such as spraying, brushing, and scraping, 3D photonic crystal structured color coatings place higher demands on the interfacial bonding between the coating and the substrate, the curing speed, and the final film quality. Therefore, there is an urgent need to develop a photonic crystal structured color coating with a simpler preparation method and superior overall performance to meet the needs of large-scale industrial applications. Summary of the Invention

[0004] To address the problems of complex preparation processes, uneven pigment distribution, and poor coating stability in existing photonic crystal structural color coatings, this invention aims to provide a novel preparation method for high-performance 3D photonic crystal structural color coatings. This invention utilizes a shell softener to mediate the preparation of a hard 3D photonic crystal film, which is then crushed at room temperature to form photonic crystal pigments. Combined with appropriate amounts of reactive monomer diluent, ultraviolet (UV) light-curing resin, and photoinitiator, the 3D photonic crystal structural color coating is prepared. The high-performance 3D photonic crystal structural color coating proposed in this invention not only simplifies the preparation process but also significantly improves the dispersibility of pigments in the resin and the stability of the final coating. The prepared structural color coating can exhibit vibrant and stable structural color effects through spraying, brushing, and scraping applications, greatly expanding the application prospects of structural color coatings in the field of industrial decoration.

[0005] In this invention, the high-performance photonic crystal structural color coating mainly consists of hard 3D photonic crystal pigments, reactive monomer diluents, ultraviolet (UV) light-curing resin, and photoinitiators. The hard 3D photonic crystal pigments are formed by crushing a photonic crystal hard film with excellent optical properties at room temperature. This photonic crystal hard film uses hard-core, hard-shell microspheres as building blocks, and through the addition of a shell softener, uniform film formation can be achieved at room temperature. It is then prepared through a continuous process of roller bending, shearing, and curing. The crushed photonic crystal pigments are mixed with the reactive monomer diluent, allowing for uniform dispersion in the UV-curing resin. With the addition of an appropriate amount of photoinitiator, the structural color coating is prepared by UV curing.

[0006] The technical solution of the present invention is described in detail below.

[0007] This invention provides a method for preparing high-performance 3D photonic crystal structured color coatings, the specific steps of which are as follows:

[0008] (1) Using hard core hard shell microspheres as the building unit, a shell softener is added to the hard core hard shell microsphere solid powder to mediate the formation of a uniform film at room temperature. The resulting film is then subjected to continuous roller bending, shearing and UV curing to obtain a hard photonic crystal film.

[0009] (2) The hard photonic crystal film was crushed at room temperature to obtain photonic crystal pigment;

[0010] (3) The photonic crystal pigment, active monomer diluent, UV-curable resin and photoinitiator are mixed and stirred at room temperature to obtain a photonic crystal structure color coating.

[0011] Preferably, in step (1), the hard-core hard-shell microspheres are prepared by semi-continuous stepwise seed emulsion polymerization or reflux precipitation polymerization; the hard core and hard shell are, from the inside out, seed, hard core and hard shell; the seed is selected from one or more of polystyrene, polymethyl methacrylate, silica, titanium dioxide or iron oxide; the hard core is composed of inorganic materials, organic polymers or inorganic-organic hybrid materials, wherein when the component is an organic polymer, its glass transition temperature is higher than 50 °C; more preferably, the hard core material is selected from one or more of polystyrene, polymethyl methacrylate, polyisobutyl methacrylate, polytert-butyl methacrylate, polyisoborneol methacrylate, polyacrylonitrile, silica, titanium dioxide and iron oxide; the crosslinking agent selected for the hard core microspheres is one or more of divinylbenzene, 1,4-butanediol diacrylate, allyl methacrylate, dipropylene glycol diacrylate and diacetone acryloyl. The hard shell is mainly composed of organic polymers with a glass transition temperature higher than 50 °C; more preferably, the hard shell material is selected from one or a mixture of several of polystyrene, polymethyl methacrylate, polyisobutyl methacrylate, polytert-butyl methacrylate, polyisoborneol methacrylate, polyacrylonitrile, polyacrylic acid, polymethyl methacrylate, polytert-butyl methacrylate, polyisobutyl methacrylate, poly-2-phenoxyethyl acrylate, poly-2-phenoxyethyl methacrylate, polylauryl acrylate, polylauryl methacrylate, polyisodecyl acrylate, polyisodecyl methacrylate, polyisoborneol acrylate, polyhydroxyethyl acrylate, polyhydroxyethyl methacrylate, polyhydroxybutyl acrylate, and polyhydroxybutyl methacrylate; more preferably, the hard shell material is selected from any one or a mixture of several of polyisobutyl methacrylate, polyacrylic acid, and polymethyl methacrylate.

[0012] Preferably, in step (1), the shell softener is a polymerizable acrylic, acrylate, or methacrylate monomer; the difference in solubility parameter (δ) between the shell softener and the shell polymer is generally less than 2; the added shell softener will enter the network of the shell polymer and swell the polymer; after the addition of the shell softener, the glass transition temperature of the shell drops significantly, generally below -20 °C. More preferably, the shell softener is selected from acrylic acid, methacrylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate, n-propyl methacrylate, isopropyl acrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl acrylate, tert-butyl methacrylate, isobutyl acrylate, isobutyl methacrylate, sec-butyl acrylate, sec-butyl methacrylate, n-octyl acrylate, n-octyl methacrylate, isooctyl acrylate, isooctyl methacrylate, dodecyl acrylate, dodecyl methacrylate, tetradecyl acrylate, dicyclopentadiene acrylate, 4-tert-butylcyclohexyl acrylate, diethylene glycol diacrylate, caprolactone acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, and ethoxylated trimethylolpropane. The shell softener is selected from one or more of the following: triacrylate, tetrahydrofuran acrylate, isoborneol acrylate, o-phenylphenoxyethyl acrylate, 2-phenoxyethyl acrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, trimethylolpropane triacrylate, glycerol triacrylate, diethylene glycol diacrylate, diethylene glycol diacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, ditrimethylolpropane tetraacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, lauryl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and dipropylene glycol diacrylate; more preferably, the shell softener is selected from one or more of the following: diethylene glycol diacrylate, diethylene glycol diacrylate, and diethylene glycol diacrylate. Preferably, in step (1), a shell softener is first added to the hard-core, hard-shell microsphere solid powder at a mass ratio of 1:4 to 4:1, and the mixture is repeatedly stirred at room temperature until the microsphere powder becomes a viscoelastic solid. Then, the viscoelastic solid is calendered with a PET film to obtain a composite film with a "PET / viscoelastic solid / PET" structure. The composite film is then subjected to continuous roll bending, shearing, and UV curing. Finally, the PET film is peeled off to obtain a hard photonic crystal film. More preferably, the continuous roll bending is performed at room temperature.

[0013] In step (2) above, preferably, the mesh size of the photonic crystal pigment is 5 to 250 mesh; more preferably, the mesh size is 50 to 150 mesh. The color of the photonic crystal pigment is determined by the size of the hard-core, hard-shell microspheres, and the pigment color can be continuously adjusted between blue and red.

[0014] Preferably, in step (3), the photonic crystal pigment is 1 to 30 parts by weight, the active monomer diluent is 5 to 45 parts by weight, the UV-curable resin is 50 to 80 parts by weight, and the photoinitiator is 1 to 5 parts by weight.

[0015] In step (3) above, the photonic crystal pigment is first dispersed in an active monomer diluent, wherein the active monomer diluent is a polymerizable monomer, and the difference in solubility parameters between this monomer and the shell polymer and the UV-curable resin is less than 2. Preferably, the active monomer diluent is one or more of acrylate monomers, methacrylate monomers, or pyrrolidone monomers; more preferably, the active monomer diluent is selected from N-vinylpyrrolidone, dicyclopentadiene acrylate, 4-tert-butylcyclohexyl acrylate, diethylene glycol diacrylate, caprolactone acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, ethoxylated trimethylolpropane triacrylate, tetrahydrofuran acrylate, isoborneol acrylate, o-phenylphenoxyethyl acrylate, 2-phenoxyethyl acrylate, 1,6-hexanediol diacrylate, di... The active monomer diacrylate is selected from one or more of the following: tripropylene glycol diacrylate, trimethylolpropane triacrylate, glycerol triacrylate, diethylene glycol diacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, bis(trimethylolpropane)tetraacrylate, tri(2-hydroxyethyl)isocyanurate triacrylate, lauryl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, and dipropylene glycol diacrylate; more preferably, the active monomer diluent is selected from one or two of the following: tetrahydrofuran acrylate, isoborneol acrylate, vinylpyrrolidone, and lauryl methacrylate.

[0016] In step (3) above, an active monomer diluent containing photonic crystal pigments is added to the UV-curable resin. Preferably, the UV-curable resin is an aliphatic polyurethane acrylate. More preferably, the UV-curable resin is selected from one or more of the following: 2423, 2421, 6200, 6201, 6205, 6206, 6210, 6211, 6280, 6298, 6300, 6310, 6350, 6370, 6380, 6390, 6410, 6411, 6460, 6600, 6601, 6606, 6901, 6902, 8400, 8402, 8403, and 9678.

[0017] In step (3) above, a photoinitiator is added to the coating to achieve efficient UV curing; preferably, the photoinitiator is one or more of hydroxy ketone, phenylacetic aldehyde ester, benzyl dimethyl ketal, amino ketone and metallocene; more preferably, the photoinitiator is selected from one or more of 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide, 1-hydroxycyclohexylphenyl ketone, benzophenone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methylpropanone, methyl benzoylformate, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholino)phenyl]-1-butanone and bis[2,6-difluoro-3-(1H-pyrrole)phenyl]titanium.

[0018] The present invention also provides a high-performance 3D photonic crystal structure color coating prepared by the above preparation method; by weight, it is composed of 1 to 30 parts by weight of photonic crystal color powder, 5 to 45 parts by weight of active monomer diluent, 50 to 80 parts by weight of ultraviolet light curing resin and 1 to 5 parts by weight of photoinitiator.

[0019] In this invention, the high-performance 3D photonic crystal structure color effect coating can be applied to the substrate by various methods such as spraying, brushing, scraping, or dipping. After UV curing, it forms a bright, uniform, and weather-resistant structure color effect coating on the decorated surface. The UV curing time is 1 to 30 seconds.

[0020] In summary, this invention enables the uniform dispersion of structural color powder in resin at room temperature, thereby forming a vibrant and stable structural color effect on the surface of the decorated material. Compared with the prior art, the advantages of this invention are as follows:

[0021] (1) Room temperature preparation, simplified process and energy saving

[0022] This invention employs a method for preparing hard photonic crystal thin films at room temperature and directly crushing them to form photonic crystal pigments. This avoids the complex processes of high-temperature curing, multi-step processing, and liquid nitrogen freezing in traditional processes, thereby significantly reducing production energy consumption and costs. At the same time, it simplifies the production process and improves the environmental friendliness and industrial adaptability of the process.

[0023] (2) The dispersibility of structural color pigments and the stability of the resulting coating are significantly improved.

[0024] Hard photonic crystal films are prepared by means of shell softeners, and the mesh count of the photonic crystal pigments formed at room temperature is highly controllable. After being uniformly mixed with reactive monomer diluents and UV-curable resins, it not only effectively prevents the agglomeration and structural damage of structural color pigments, but also enhances the interfacial bonding between the coating and the substrate, ensuring a long-lasting and stable structural color effect and avoiding the microcracks, delamination, and fading problems that are prone to occur in traditional technologies.

[0025] (3) Fast curing speed and wide range of applications

[0026] By utilizing appropriate amounts of photoinitiator and UV-curing resin system, this invention achieves rapid UV curing of photonic crystal structure color coatings, significantly shortening the production cycle. Furthermore, this structure color effect coating can be applied to various substrates via spraying, brushing, scraping, and dipping. The resulting coating not only boasts vibrant colors and excellent optical properties but also exhibits good weather resistance and photobleaching resistance, meeting the requirements of high-end decoration and anti-counterfeiting applications. Attached Figure Description

[0027] Figure 1 Field emission scanning electron microscope (FESEM) image of a hard-core, hard-shell particle.

[0028] Figure 2 Application photos of high-performance 3D photonic crystal structure color effect coatings.

[0029] Figure 3 Stability testing of coatings formed by high-performance 3D photonic crystal structure color effect coatings.

[0030] Figure 4 Differential scanning calorimetry (DSC) curves of hard-core hard-shell microsphere powder and after the addition of shell softener.

[0031] Figure 5 Macroscopic photograph of the coating formed by high-performance 3D photonic crystal structure color effect paint.

[0032] Figure 6 Structural color coatings formed by coatings formulated with different shell softeners and reactive diluents. Detailed Implementation

[0033] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments, so that those skilled in the art can more fully understand the present invention. The described embodiments are only some embodiments of the present invention, not all embodiments. It should be noted that they should not be used to limit the scope of protection of the present invention. For those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be covered within the scope of protection of the embodiments of the present invention.

[0034] Example 1

[0035] This embodiment provides a high-performance 3D photonic crystal structure color effect coating and its preparation method. The synthesized photonic crystal color powder is green. The synthesis method of the hard-core hard-shell microspheres can adopt the semi-continuous stepwise seed emulsion polymerization method used in CN 115183900 B. The monomer for polymerizing the shell is isobutyl methacrylate, resulting in hard-core hard-shell microspheres with a particle size of about 200 nanometers. Figure 1 The monodispersity index is less than 0.05. The prepared hard-core hard-shell microsphere emulsion is spray-dried to obtain a solid powder, which is then used as a raw material for preparing structural color effect coatings. The specific preparation process of high-performance 3D photonic crystal structural color effect coatings is as follows:

[0036] Step 1: Add 50 parts by weight of shell softener diethylene glycol diacrylate to 50 parts by weight of hard-core hard-shell microsphere solid powder, and stir repeatedly until the microsphere powder becomes a viscoelastic solid; further, calender the viscoelastic solid with PET film to obtain a composite film (PET / viscoelastic solid / PET), and obtain a photonic crystal film with excellent properties by continuously bending, shearing and curing the obtained composite film through continuous roller bending.

[0037] Step 2: Peel the prepared photonic crystal film from the PET film, then put it into a mixer and crush it at room temperature. Use sieves of different mesh sizes to sieve the photonic crystal pigments to obtain photonic crystal pigments of different mesh sizes.

[0038] Step 3: Select 15 parts by weight of 100-mesh 3D photonic crystal pigment and add it to 20 parts by weight of tetrahydrofuran acrylate, and stir thoroughly. Then add the tetrahydrofuran acrylate containing the pigment to 70 parts by weight of 9-functionality resin 2421, stir to disperse the pigment evenly, and finally add 1 part by weight of photoinitiator 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide to complete the preparation of the 3D photonic crystal structure color effect coating.

[0039] Step 4: Apply the obtained structural color coating to the object by brushing, and then cure it by irradiating it with a 365 nm ultraviolet lamp for 3 seconds. Figure 2 ).

[0040] The obtained coating was subjected to performance tests, including solvent resistance and related stability tests. The test results showed that the obtained coating has good stability. Figure 3 ).

[0041] Example 2

[0042] The implementation process of the 3D photonic crystal structured color coating provided in this embodiment is the same as that in Example 1. The difference lies in the preparation of the hard core and hard shell particles. The hard core is a silica microsphere synthesized by the Stöber method, and the hard shell is coated on the hard core by reflux precipitation. The main component is polyisobutyl methacrylate. The synthesis method can follow the reflux precipitation polymerization method used in CN 118271895A and CN116376323A. The core-shell microsphere solid can be obtained by freeze-drying.

[0043] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0044] Example 3

[0045] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in Embodiment 1, the difference being that in the preparation of the hard-core hard-shell particles, the diameter of the obtained hard-core hard-shell particles is 183 nanometers, and the monodispersity index is 0.02. The color powder prepared using microspheres of this particle size is blue.

[0046] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0047] Example 4

[0048] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in Embodiment 1. The difference lies in the preparation of the hard-core hard-shell particles, where the diameter of the obtained hard-core hard-shell particles is 233 nanometers and the monodispersity index is 0.04. The color powder prepared using microspheres of this particle size is red.

[0049] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0050] Example 5

[0051] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in the preparation of hard core and hard shell particles, the hard core and hard shell particles obtained are composed of a copolymer of polyisobutyl methacrylate, polyacrylic acid and polymethyl methacrylate.

[0052] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0053] Example 6

[0054] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1, except that in step one, 30 parts by weight of shell softener are mixed with 70 parts by weight of hard core hard shell microsphere powder.

[0055] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0056] Example 7

[0057] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step one, the shell softener added is a mixture of diethylene glycol diacrylate and triethylene glycol diacrylate.

[0058] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0059] Example 8

[0060] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 15 parts by weight of 50-mesh 3D photonic crystal color powder are added to 20 parts by weight of tetrahydrofuran acrylate and stirred thoroughly.

[0061] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0062] Example 9

[0063] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 15 parts by weight of 150-mesh 3D photonic crystal color powder are added to 20 parts by weight of tetrahydrofuran acrylate and stirred thoroughly.

[0064] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0065] Example 10

[0066] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 15 parts by weight of 100-mesh 3D photonic crystal color powder are added to 20 parts by weight of isoborneol acrylate and stirred thoroughly.

[0067] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0068] Example 11

[0069] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 15 parts by weight of 100-mesh 3D photonic crystal color powder are added to 20 parts by weight of vinylpyrrolidone and stirred thoroughly.

[0070] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0071] Example 12

[0072] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 15 parts by weight of 100-mesh 3D photonic crystal color powder are added to 20 parts by weight of lauryl methacrylate and stirred thoroughly.

[0073] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0074] Example 13

[0075] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, tetrahydrofuran acrylate containing photonic crystal color powder is added to 70 parts by weight of 2423 resin.

[0076] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0077] Example 14

[0078] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, tetrahydrofuran acrylate containing photonic crystal color powder is added to 50 parts by weight of 2423 resin and 20 parts by weight of 9678 resin.

[0079] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0080] Example 15

[0081] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 2.5 parts by weight of photoinitiator 2,4,6-trimethylbenzoyl-di(p-tolyl)phosphine oxide is added to the prepared color powder coating.

[0082] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0083] Example 16

[0084] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step three, 1 part by weight of photoinitiator 2,4,6-trimethylbenzoyl-bis(p-tolyl)phosphine oxide and 1 part by weight of 1-hydroxycyclohexylphenyl ketone are added to the prepared color powder coating.

[0085] The stability of the prepared 3D photonic crystal structure color coating is the same as that of Example 1.

[0086] Example 17

[0087] The implementation process of the 3D photonic crystal structure color coating provided in this embodiment is the same as that in embodiment 1. The difference is that in step four, the 3D photonic crystal structure color coating is sprayed onto the object to be decorated by spraying.

[0088] The stability of the prepared 3D photonic crystal structured color coating is the same as that in Example 1.

[0089] Performance testing of high-performance 3D photonic crystal structured color coatings:

[0090] Coating stability test:

[0091] The 3D photonic crystal coating obtained in Example 1 was placed in organic solvents (tetrahydrofuran, acetone, dioxane, and dimethylformamide) at pH=1 and pH=13 for 1 minute each, followed by brushing, wiping, and tapping continuity tests. The test results showed that the optical properties and dimensions of the coating remained unchanged. Figure 3 ).

[0092] Differential scanning calorimetry:

[0093] Differential scanning calorimetry (DSC) was performed on the hard-core, hard-shell microsphere solid powder obtained in Example 1. The results showed that the glass transition temperature of the hard core was 110 °C, and the glass transition temperature of the hard shell was 62 °C. (See attached table for test results.) Figure 4 a.

[0094] Furthermore, the glass transition temperature of the core-shell microsphere solid was tested after adding the shell softener diethylene glycol diacrylate. The results showed that the glass transition temperature of the hard shell was -25 °C. (See the test results below.) Figure 4 b.

[0095] Structural color coating appearance:

[0096] The colors of the coatings formed by the green / blue / red tri-color photonic crystal coatings obtained in Examples 1, 3, and 4 are recorded by photograph. Figure 5 ).

[0097] The appearance of structural color coatings formed by different shell softeners and reactive diluents:

[0098] The colors of the coatings formed by the structural color photonic crystal coatings obtained in Examples 7 and 11 were recorded by photograph. Figure 6 ).

[0099] Comparative Example 1

[0100] The 3D photonic crystal structure color coating was prepared using a method essentially the same as in Example 1. The difference was that, in the synthesis of core-shell microspheres, the shell layer was mainly composed of polybutyl acrylate with a glass transition temperature of -40 °C.

[0101] The prepared photonic crystal thin film cannot be easily broken into powder at room temperature.

[0102] Comparative Example 2

[0103] The 3D photonic crystal structure color coating was prepared using a method essentially the same as that in Example 1, except that the shell softener used was ethyl acetate.

[0104] The prepared photonic crystal thin film has poor optical properties and an overall whitish color.

[0105] Comparative Example 3

[0106] The 3D photonic crystal structure color coating was prepared using a method essentially the same as that in Example 1, except that tetrahydrofuran was used as the diluent.

[0107] The prepared 3D photonic crystal structure color coating contains a large number of bubbles.

[0108] The structural color coating of the present invention can be applied to a substrate by various methods such as spraying, brushing, scraping, or dipping. After UV curing, it forms a bright, uniform, and weather-resistant structural color coating on the decorated surface. Compared with traditional coatings, this structural color coating not only avoids the problem of easy fading of dyes and pigments in traditional coatings, but also utilizes the photonic crystal structure to control the interference effect of light, resulting in higher color stability. In summary, the present invention achieves the efficient preparation of high-performance 3D photonic crystal structural color coatings.

Claims

1. A method for preparing high performance 3D photonic crystal structural color paint, characterized in that, The specific steps are as follows: (1) In the hard core hard shell microspheres as the building unit, in the hard core hard shell microspheres solid powder, add shell softener mediation, solid powder at room temperature uniform film, then the film is obtained by continuous over roller bending, shearing and curing, get hard photonic crystal thin film; (2) the hard photonic crystal thin film is broken at room temperature, get photonic crystal color powder; (3) the photonic crystal color powder, active monomer diluent, ultraviolet curing resin and photoinitiator are mixed and stirred at room temperature, and the photonic crystal structure color coating is obtained; wherein: In step (1), first, according to the mass ratio of 4:1~1:4, add shell softener in the hard core hard shell microspheres solid powder, room temperature conditions repeated stirring to the microspheres powder into viscoelastic state solid, the difference between the shell softener and the shell polymer of the shell polymer is less than 2; Then the viscoelastic state solid and PET film are calendered to obtain a composite film with the structure of "PET / viscoelastic state solid / PET", and then the composite film is continuously over roller bent, sheared and ultraviolet cured at room temperature. Finally, the PET film is peeled off to obtain a hard photonic crystal thin film; In step (1), the shell softener is acrylate or methacrylate monomer; In step (3), the active monomer diluent is a polymerizable monomer, and the difference between the solubility parameter of the monomer and the shell polymer and the ultraviolet curing resin is less than 2.

2. The production method according to claim 1, characterized by, In step (1), the hard core hard shell microspheres are prepared by semi-continuous step-by-step seed emulsion polymerization or reflux precipitation polymerization, and the monodispersity index is less than 0.05 and the size is between 120 nm and 400 nm; The hard core hard shell is composed of seed, hard core and hard shell from inside to outside; The seed is selected from one or more of polystyrene, polymethyl methacrylate, silicon dioxide, titanium dioxide or ferroferric oxide; The hard core is composed of inorganic material, organic polymer or inorganic-organic hybrid material, wherein when the composition is organic polymer, the glass transition temperature is higher than 50 ℃; The hard shell is mainly composed of organic polymer, and the glass transition temperature is higher than 50 ℃.

3. The preparation method according to claim 1, characterized in that, In step (2), the mesh number of the photonic crystal color powder is 5-250.

4. The production method according to claim 1, characterized by, In step (3), according to the weight fraction, the photonic crystal color powder is 1-30 parts by weight, the active monomer diluent is 5-45 parts by weight, the ultraviolet curing resin is 50-80 parts by weight, and the photoinitiator is 1-5 parts by weight.

5. The method of claim 1, wherein, In step (3), the active monomer diluent is one or more of acrylate monomer, methacrylate monomer or pyrrolidone monomer, the ultraviolet curing resin is aliphatic polyurethane acrylate, and the photoinitiator is one or more of hydroxy ketone, phenylacetic aldehyde ester, benzyl dimethyl ketal, amino ketone or metallocene.

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