Photonic crystal compositions, films based on dual cure systems, and methods of making the same

Abstract

The present application relates to a photonic crystal composition based on a double curing system, a film and a preparation method thereof, raw materials of the photonic crystal composition comprising the following components by mass fraction: nanomicrospheres 50-80 parts; acrylate reactants 10-30 parts; photoinitiators 0.5-1.5 parts; thermally cured amino resins 1-10 parts; the photonic crystal composition has good adhesion on a plastic substrate and has high solvent resistance.

Description

Technical Field

[0001] This invention relates to the field of materials, and more specifically to photonic crystal compositions, thin films, and preparation methods thereof based on dual-curing systems. Background Technology

[0002] The color of matter is mainly divided into chemical color and structural color. Chemical color is generated by chromophores, while structural color is achieved through internal microstructure. Microspheres, after being crystallized through a three-dimensional ordered arrangement, can be called photonic crystals. When light is incident on a photonic crystal, due to its periodic structure, the light undergoes diffraction or interference, thus reflecting light of a specific wavelength, i.e., Bragg reflection. Furthermore, as the size of the microspheres and the lattice spacing change, photonic crystals can reflect light from the ultraviolet to the infrared band. When the reflected wavelength is within the visible light range, it can produce iridescent colors as a structural color.

[0003] When preparing photonic crystal films using photocurable photonic crystal compositions, problems often arise such as low double bond conversion rates and poor adhesion on many plastic substrates. Previously, coating photonic crystal compositions onto PET films often lacked adhesion, requiring the application of a primer layer to improve adhesion. Furthermore, the poor solvent resistance of photonic crystal coatings led to numerous problems in subsequent processing. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the first objective of the present invention is to provide a photonic crystal composition based on a dual curing system, which has good adhesion to plastic substrates and high solvent resistance.

[0005] The second objective of this invention is to provide a photonic crystal thin film, which is a composite thin film with high interlayer adhesion and high solvent resistance.

[0006] A third objective of this invention is to provide a method for preparing the aforementioned photonic crystal thin film.

[0007] To achieve the first objective of this invention, this invention provides a photonic crystal composition based on a dual-curing system. The raw materials of the photonic crystal composition include the following components in parts by weight: 50-80 parts of nanospheres; 10-30 parts of acrylate reactants; 0.5-1.5 parts of photoinitiator; and 1-10 parts of thermosetting amino resin.

[0008] In some embodiments of the present invention, the average particle size of the nanospheres is 100-400 nm, and the polydispersity index (PDI) is less than 0.15.

[0009] In some embodiments of the present invention, the nanospheres are selected from at least one of polymer microspheres, inorganic microspheres, and polymer-inorganic composite microspheres; the polymer microspheres include at least one of polystyrene microspheres and core-shell polymer microspheres, wherein the core material of the core-shell polymer microspheres includes organic or inorganic materials, and the shell material of the core-shell polymer microspheres includes polymer elastomer materials; the inorganic microspheres include at least one of silicon dioxide, titanium dioxide, iron tetroxide, and zinc sulfide.

[0010] In some embodiments of the present invention, the acrylate reactants include monomers and / or oligomers of at least one of acrylates and methacrylates.

[0011] In some embodiments of the present invention, the acrylate reactants include those selected from methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, neopentyl methacrylate, tert-pentyl methacrylate, n-hexyl methacrylate, 2-ethylbutyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, and n-octyl methacrylate. Ester, 2-Ethylhexyl (meth)acrylate, Nonyl (meth)acrylate, Decyl (meth)acrylate, Dodecyl (meth)acrylate, Tridecyl (meth)acrylate, Tetradecyl (meth)acrylate, Hexadecyl (meth)acrylate, Octadecyl (meth)acrylate, Docosyl (meth)acrylate, Norborneol (meth)acrylate, Norborneol Methyl (meth)acrylate, Isoborneol (meth)acrylate, Borneol (meth)acrylate, Menthyl (meth)acrylate, Octahydroindene (meth)acrylate, Adamantyl (meth)acrylate, (M) Dimethyl adamantyl acrylate, phenyl acrylate, 2-ethylphenyl acrylate, indole acrylate, toluene acrylate and benzyl acrylate, acryloylmorpholine, N-hydroxyethyl acrylamide, dimethyl acrylamide, diethyl acrylamide, isopropyl acrylamide, N-vinylcaprolactam, ethoxyphenol acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, cyclotrimethylolpropane formal acrylate, 4-tert-butylcyclohexyl acrylate, ethoxyethoxyethyl acrylate, diethoxyphenol acrylate, 1,6 - At least one of the following: hexanediol diacrylate, tripropylene glycol diacrylate, dipropylene glycol diacrylate, triethylene glycol diacrylate, dipropoxyneopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triethoxytrimethylolpropane triacrylate, hexaethoxytrimethylolpropane triacrylate, nonethoxytrimethylolpropane triacrylate, pentadecylethoxytrimethylolpropane triacrylate, tripropoxytrimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate.

[0012] In some embodiments of the present invention, the photoinitiator is selected from at least one of phenylalkyl ketone type photopolymerization initiators, acylphosphine oxide type photopolymerization initiators, hydrogen abstraction type photopolymerization initiators, and oxime ester type photopolymerization initiators.

[0013] In some embodiments of the present invention, the photoinitiator includes at least one selected from bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2,4-diethylthiazolinone, and 2-isopropylthioxanthraphenone.

[0014] In some embodiments of the present invention, the amino resin is selected from at least one of methylated melamine resin, n-butylated melamine resin, benzoated melamine resin, urea-formaldehyde resin, and glycourea resin.

[0015] In some embodiments of the present invention, the methyl etherified melamine resin is selected from at least one of Cymel 303LF, Cymel 304, Cymel 308, Cymel 323, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 373, Cymel 380, and Cymel 385.

[0016] In some embodiments of the present invention, the n-butyl etherified melamine resin is selected from at least one of Cymel 243-3, Cymel 247-10, and Cymel 1158.

[0017] In some embodiments of the present invention, the phenyl melamine resin is selected from at least one of Cymel 659, Cymel 1123, and Cymel 5010.

[0018] In some embodiments of the present invention, the urea-formaldehyde resin is selected from at least one of Cymel U-65, Cymel U-80, and Cymel U-15.

[0019] In some embodiments of the present invention, the glycourea resin is selected from at least one of Cymel 1170 and Cymel 1172.

[0020] To achieve the second objective of the present invention, the present invention provides a photonic crystal thin film, which includes a plastic substrate layer and a photonic crystal layer directly disposed on the plastic substrate layer. The photonic crystal layer is prepared by curing the photonic crystal composition described in any of the above embodiments. In the photonic crystal layer, the nanospheres are arranged in a three-dimensional order.

[0021] In some embodiments of the present invention, the plastic substrate layer is selected from at least one of polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanediol, polymethyl methacrylate, polyvinyl alcohol, polynaphthalene dicarboxylate, polycarbonate, polyurethane, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride, thermoplastic polyurethane elastomer, polyvinylidene fluoride, ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyolefin.

[0022] In some embodiments of the present invention, the curing includes photocuring and thermal curing.

[0023] To achieve the third objective of this invention, this invention provides a method for preparing a photonic crystal thin film as described in any of the above embodiments, comprising the following steps:

[0024] Step 1: Mix the nanospheres, acrylate reactants, photoinitiator and thermosetting amino resin evenly to obtain a photonic crystal composition;

[0025] Step 2: Coat the photonic crystal composition onto a plastic substrate layer and dry it to obtain a composite film;

[0026] Step 3: The composite film is regularized to ensure that the nanospheres are arranged in a three-dimensional order;

[0027] Step 4: Perform photocuring treatment on the composite film;

[0028] Step 5: Perform thermosetting treatment on the composite film.

[0029] In some embodiments of the present invention, in step one, the acrylate reactants and photoinitiator are mixed evenly, mixed with nanospheres, stirred evenly, and then amino resin is added to obtain a photonic crystal coating composition.

[0030] In some embodiments of the present invention, in step two, the drying is carried out at 50-80°C, and a release layer is then laminated onto the photonic crystal composition to obtain a composite film.

[0031] In some embodiments of the present invention, in step four, the photocuring process is performed under ultraviolet light, with a cumulative light intensity of not less than 500 mJ / cm². 2 .

[0032] In some embodiments of the present invention, in step five, the thermosetting treatment is performed at 100–150°C.

[0033] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0034] The photonic crystal composition of the present invention is based on a photo-thermal dual curing system. After photocuring and thermal curing, the photonic crystal composition can improve the adhesion on plastic substrates, eliminating the need to apply a primer coating to the plastic substrate before applying the photonic crystal composition, thus saving steps. It also improves the solvent resistance of the photonic crystal film, avoiding post-processing problems caused by poor solvent resistance of the photonic crystal. Detailed Implementation

[0035] The present invention provides a photonic crystal composition that can be directly attached to a plastic substrate to obtain a composite film. The photonic crystal composition is not easily separated from the plastic substrate during processing or use, and is suitable for decoration, packaging and other fields.

[0036] Specifically, the raw materials of the photonic crystal composition in this embodiment include the following components in parts by weight: 50-80 parts of nanospheres; 10-30 parts of acrylate reactants; 0.5-1.5 parts of photoinitiator; and 1-10 parts of thermosetting amino resin.

[0037] In this embodiment, nanospheres are used to form a three-dimensionally ordered periodic structure in the photonic crystal composition, thereby forming a photonic crystal that exhibits structural color. Acrylic ester reactants and a photoinitiator constitute a photocurable polymerization system, while a thermosetting amino resin constitutes a thermosetting polymerization system. The photocurable and thermosetting polymerization systems are mixed together to form a resin matrix that disperses and fixes the nanospheres. Compared to existing photonic crystal compositions using a single photocurable polymerization system, this embodiment uses both photocurable and thermosetting polymerization systems. While maintaining the flexibility and mechanical strength of the photonic crystal layer, the thermosetting amino resin acts as a binder dispersed in the acrylate reactants, improving the adhesion of the photonic crystal composition to the plastic substrate. This eliminates the need to coat the plastic substrate with a primer before coating the photonic crystal composition, saving steps and improving the solvent resistance of the photonic crystal film, avoiding processing problems caused by poor solvent resistance.

[0038] In some examples, the raw materials of the photonic crystal composition consist of the following components in parts by weight: 50-80 parts of nanospheres; 10-30 parts of acrylate reactants; 0.5-1.5 parts of photoinitiator; and 1-10 parts of thermosetting amino resin. Apart from unavoidable impurities, the above photonic crystal composition does not contain any components other than nanospheres, acrylate reactants, photoinitiator, and thermosetting amino resin, resulting in a simpler raw material formulation that is sufficient to achieve improved adhesion and solvent resistance.

[0039] In some examples, the mass fraction of the nanospheres in the photonic crystal composition can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, etc.; the mass fraction of the acrylate reactants can be 10 parts, 15 parts, 25 parts, 30 parts, etc.; the mass fraction of the photoinitiator can be 0.5 parts, 1 part, 1.5 parts, etc.; and the mass fraction of the thermosetting amino resin can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.

[0040] In some examples, the average particle size of the nanospheres in the nanospheres is 100–400 nm, and the polydispersity index (PDI) is less than 0.15. When the particle size and polydispersity of the nanospheres are within the above range, the resulting photonic crystal thin film can achieve angle-dependent color variation over a larger spectral range in the visible light range, and makes the structural color more uniform.

[0041] In some examples, the nanospheres are selected from at least one of polymer microspheres, inorganic microspheres, and polymer-inorganic composite microspheres; the polymer microspheres include at least one of polystyrene microspheres and core-shell polymer microspheres, wherein the core material of the core-shell polymer microspheres includes organic or inorganic materials, and the shell material of the core-shell polymer microspheres includes polymer elastomer materials; the inorganic microspheres include at least one of silica, titanium dioxide, iron tetroxide, and zinc sulfide. These nanospheres are readily available, their particle size and polydispersity are easily controlled, and their preparation process is mature.

[0042] In some examples, the acrylate reactants include monomers and / or oligomers of at least one of acrylates and methacrylates, which are capable of sufficient photocuring. In some examples, the acrylate reactants include those selected from methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, neopentyl methacrylate, tert-pentyl methacrylate, n-hexyl methacrylate, 2-ethylbutyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, etc. 2-Ethylhexyl acrylate, (meth)nonyl acrylate, (meth)decyl acrylate, (meth)dodecyl acrylate, (meth)tridecyl acrylate, (meth)tetradecyl acrylate, (meth)hexadecyl acrylate, (meth)octadecyl acrylate, (meth)docodecyl acrylate, (meth)norborneol acrylate, (meth)norborneol methyl acrylate, (meth)isoborneol acrylate, (meth)borneol acrylate, (meth)menthol acrylate, (meth)octahydroindene acrylate, (meth)adamantyl acrylate, (meth)acrylic acid Dimethyl adamantyl ester, phenyl methacrylate, 2-ethylphenyl methacrylate, indole methacrylate, toluene methacrylate and benzyl methacrylate, acryloylmorpholine, N-hydroxyethylacrylamide, dimethylacrylamide, diethylacrylamide, isopropylacrylamide, N-vinylcaprolactam, ethoxyphenol acrylate, benzyl acrylate, tetrahydrofurfuryl acrylate, cyclotrimethylolpropane formaldehyde acrylate, 4-tert-butylcyclohexyl acrylate, ethoxyethoxyethyl acrylate, diethoxyphenol acrylate, 1,6-hexanediol di The acrylates include at least one of the following: dipropylene glycol diacrylate, dipropylene glycol diacrylate, diethylene glycol diacrylate, dipropoxyneopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triethoxytrimethylolpropane triacrylate, hexaethoxytrimethylolpropane triacrylate, nonethoxytrimethylolpropane triacrylate, pentadecylethoxytrimethylolpropane triacrylate, tripropoxytrimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and dipentaerythritol hexaacrylate, or oligomers thereof. In this embodiment, the type of the above-mentioned (meth)acrylates can be selected according to the actual polymerization reaction requirements and the mechanical properties of the photonic crystal layer.

[0043] In some examples, the photoinitiator is selected from at least one of phenylalkyl ketone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, hydrogen abstraction photopolymerization initiators, and oxime ester photopolymerization initiators. In some examples, the photoinitiator includes one or any combination of two or more of the following: bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (photoinitiator 819), 2,4,6-trimethylbenzoyl diphenylphosphine oxide (TPO), ethyl 2,4,6-trimethylbenzoyl phenylphosphonate (TPO-L), 1-hydroxycyclohexylbenzophenone (184), 2-hydroxy-2-methyl-1-phenyl-1-propanone (1173), 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone (369), 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (379), 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone (907), 2,4-diethylthiazolinone (DETX), and 2-isopropylthioxanthone (ITX). Preferably, 2,4,6-trimethylbenzoyl diphenylphosphine oxide (photoinitiator TPO) is used. The above photoinitiator can initiate the polymerization of (meth)acrylate monomers or their oligomers under ultraviolet light.

[0044] In some examples, the amino resin is selected from at least one of methyl etherified melamine resin, n-butyl etherified melamine resin, phenyl melamine resin, urea-formaldehyde resin, and glycourea resin. In some examples, the methyl etherified melamine resin is selected from at least one of Cymel 303LF, Cymel 304, Cymel 308, Cymel 323, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 373, Cymel 380, and Cymel 385. The n-butyl etherified melamine resin is selected from at least one of Cymel 243-3, Cymel 247-10, and Cymel 1158. The phenyl melamine resin is selected from at least one of Cymel 659, Cymel 1123, and Cymel 5010. The urea-formaldehyde resin is selected from at least one of Cymel U-65, Cymel U-80, and Cymel UM-15. The glycourea resin is selected from at least one of Cymel 1170 and Cymel 1172. The above-mentioned amino resin can be uniformly dispersed in acrylate reactants and polymerized and cured under heat, thereby improving the adhesion of the photonic crystal layer to the plastic substrate and enhancing the solvent resistance of the photonic crystal layer.

[0045] In some examples, this embodiment also provides a photonic crystal film, which includes a plastic substrate layer and a photonic crystal layer directly disposed on the plastic substrate layer. The photonic crystal layer is prepared by curing the photonic crystal composition described in any of the above embodiments. The photonic crystal composition of this embodiment can be directly disposed on the plastic substrate layer by means of coating or other methods, and has good adhesion to the plastic substrate, without the need to first apply a primer layer to the plastic substrate layer.

[0046] In some examples, the plastic substrate layer is selected from at least one of polyethylene terephthalate (PET), polyethylene terephthalate-1,4-cyclohexanediol (PETG), polymethyl methacrylate (PMMA), polyvinyl alcohol (PVA), polynaphthalene dicarboxylate (PEN), polycarbonate (PC), polyurethane (PU), acrylonitrile-butadiene-styrene copolymer (ABS), polyvinyl chloride (PVC), thermoplastic polyurethane elastomer (TPU), polyvinylidene fluoride (PVDF), ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral (PVB), and polyolefin (POE). The aforementioned plastic substrate layer possesses good mechanical properties and can provide support for the photonic crystal layer.

[0047] In some examples, the curing includes photocuring and thermal curing. Since the polymer matrix of the photonic crystal composition contains photocurable and thermally curable reactants, the photocurable and thermally curable reactants are polymerized by photocuring and thermal curing, respectively.

[0048] In some examples, this embodiment also provides a method for preparing a photonic crystal thin film according to any of the above-described schemes, which includes the following steps: Step 1: Mixing nanospheres, acrylate reactants, photoinitiators, and thermosetting amino resins uniformly to obtain a photonic crystal composition; Step 2: Coating the photonic crystal composition onto a plastic substrate layer and drying it to obtain a composite film; Step 3: Regularizing the composite film to make the nanospheres arranged in a three-dimensional order; Step 4: Performing photocuring treatment on the composite film; Step 5: Performing thermocuring treatment on the composite film. As can be seen, the preparation method of the photonic crystal film in this embodiment is simple. Through a process of photocuring followed by thermal curing, the acrylate reactants, which serve as the main resin matrix, are first polymerized and cured under the action of light. The photocured product can provide sufficient toughness and mechanical strength to the photonic crystal layer, disperse and fix the nanospheres, and the photocuring reaction conditions are mild, which will not cause displacement of the nanospheres after regularization treatment, and can well maintain the three-dimensional orderly arrangement and positioning of the nanospheres. Then, the thermocuring reactants dispersed in the photocuring process, namely amino resin, are cured. Amino resin has better adhesion to plastic substrates than acrylate reactants, thereby improving the overall adhesion of the photonic crystal layer. Furthermore, the thermocuring of amino resin can improve the density and solvent resistance of the photonic crystal layer, avoiding discoloration and processing problems caused by solvent penetration of the photonic crystal.

[0049] In some examples, in step one, the acrylate reactants and photoinitiator are mixed uniformly, then mixed with nanospheres, stirred until homogeneous, and then an amino resin is added to obtain the photonic crystal coating composition. Using the above mixing steps allows for a more uniform dispersion of the raw material components in the photonic crystal composition.

[0050] In some examples, in step two, the drying is carried out at a relatively low temperature of 50–80°C to prevent premature curing of the thermosetting reactants. After drying, a release layer is laminated onto the photonic crystal composition to obtain a composite film. The release layer can protect the photonic crystal layer during subsequent regularization processes. The release layer can be peeled off before use. The release layer can be a plastic release film.

[0051] In some examples, in step four, the photocuring process is performed under ultraviolet light, with a cumulative light intensity of not less than 500 mJ / cm². 2 The light curing conditions are mild and allow the acrylate reactants to fully cure.

[0052] In some examples, in step five, the thermosetting treatment is performed at 100–150°C to allow the thermosetting amino resin to fully cure.

[0053] The present invention will be further described in detail below through specific embodiments. In the following embodiments and comparative examples, unless otherwise specified, substances with the same name are of the same kind, and the operation steps that describe the same process steps are the same.

[0054] The raw materials used in the following examples and comparative examples are shown in Table 1 below.

[0055] Table 1. Raw materials used in the examples and comparative examples.

[0056]

[0057]

[0058] Example 1

[0059] The photonic crystal thin film in this embodiment is fabricated using the following steps:

[0060] S1. Preparation of photonic crystal coating composition: 12.5 parts by mass of HDDA, 12.5 parts by mass of TMPTA and 1 part by mass of TPO are mixed evenly, and then mixed with 70 parts by mass of nanospheres. After stirring evenly, 5 parts by mass of Cymel 385 are added to obtain the photonic crystal coating composition.

[0061] S2. The above-mentioned photonic crystal film coating composition is coated on a PET film (produced by Hefei Lucky Film, model: FG41S, thickness 100μm), dried at 60℃ for 1min, and then laminated with a release substrate to obtain a composite film.

[0062] S3. The composite film is regularized to obtain a composite film with crystallized microspheres.

[0063] S4. The crystallized composite film is photocured using a 395nm LED-UV light source, with a cumulative light intensity of 1000mJ / cm². 2 Thus, a composite photonic crystal thin film with microsphere crystallization and fixation was obtained;

[0064] S5. The crystallized composite photonic crystal film is thermally cured at 130°C for 20 minutes to obtain a photonic crystal film.

[0065] Examples 2 to 7

[0066] Based on Example 1, the amount of raw materials was adjusted, and the photonic crystal thin films of Examples 2 to 7 were prepared using the same steps as in Example 1. The raw materials for each example are shown in Table 2 below, where the component values ​​are in parts by mass.

[0067] Comparative Examples 1 to 4

[0068] Based on Example 1, the types and amounts of raw materials were adjusted, and the raw materials were mixed evenly in step S1. In steps S2 to S5, the same steps as in Example 1 were used to prepare the photonic crystal films of Comparative Examples 1 to 4. The raw materials of each comparative example are shown in Table 2 below, where the component values ​​are in parts by mass.

[0069] Performance testing

[0070] The photonic crystal films obtained in Examples 1 to 7 and Comparative Examples 1 to 4 were subjected to adhesion tests, reflection wavelength and reflectivity tests, and solvent resistance tests. The various test methods are as follows:

[0071] Adhesion test: Perform the cross-cut adhesion test according to ASTM D4541-09;

[0072] Reflection wavelength and reflectance: measured using a violet-visible spectrophotometer;

[0073] Solvent resistance: The photonic crystal film was immersed in ethyl acetate for 2 minutes and the color was compared. No color change was rated P, and color change was rated NG.

[0074] The test results are shown in Table 2 below.

[0075] Table 2. Raw material and performance test results for the examples and comparative examples.

[0076]

[0077]

[0078] As can be seen from the above, the photonic crystal layer of the present invention exhibits excellent adhesion to the plastic substrate, eliminating the need for a primer coating and significantly improving the solvent resistance of the photonic crystal film. In contrast, Comparative Examples 1 to 3, which do not use thermopolymerizable amino resin, show poor adhesion and solvent resistance; even increasing the amount of acrylate reactants or initiator does not improve adhesion and solvent resistance. Comparative Example 4, which does not use acrylate reactants and uses only thermopolymerizable amino resin as the resin matrix, results in a film that does not exhibit structural color.

[0079] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A photonic crystal composition based on a dual-curing system, characterized in that... The raw materials of the photonic crystal composition include the following components in parts by weight: 70 parts of nanospheres; 25-30 parts of acrylate reactants; Photoinitiator 0.5–1.5 parts; 1-5 parts of thermosetting amino resin; The nanospheres form a three-dimensionally ordered periodic structure in the photonic crystal composition; The thermosetting amino resin is selected from at least one of methylated melamine resin, n-butylated melamine resin, and benzoated melamine resin; The photonic crystal composition is first photocured and then thermocured.

2. The photonic crystal composition based on a dual-curing system according to claim 1, characterized in that... The average particle size of the nanospheres is 100–400 nm, and the polydispersity index (PDI) is less than 0.

15. The nanospheres are selected from at least one of polymer microspheres, inorganic microspheres, and polymer-inorganic composite microspheres; the polymer microspheres include at least one of polystyrene microspheres and core-shell structured polymer microspheres, wherein the core material of the core-shell structured polymer microspheres includes organic or inorganic materials, and the shell material of the core-shell structured polymer microspheres includes polymer elastomer materials; the inorganic microspheres include at least one of silicon dioxide, titanium dioxide, iron tetroxide, and zinc sulfide.

3. The photonic crystal composition based on a dual-curing system according to claim 1 or 2, characterized in that... The acrylate reactants include monomers and / or oligomers of at least one of acrylates and methacrylates; The photoinitiator is selected from at least one of the following: phenylalkyl ketone type photopolymerization initiator, acylphosphine oxide type photopolymerization initiator, hydrogen abstraction type photopolymerization initiator, and oxime ester type photopolymerization initiator.

4. The photonic crystal composition based on a dual-curing system according to claim 3, characterized in that... The acrylate reactants include those selected from methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, neopentyl methacrylate, tert-pentyl methacrylate, n-hexyl methacrylate, 2-ethylbutyl methacrylate, cyclohexyl methacrylate, n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, tridecyl methacrylate, tetradecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, dodecyl methacrylate, isoborneol methacrylate, menthyl methacrylate, etc. adamantyl methacrylate, phenyl methacrylate, 2-ethylphenyl methacrylate, toluene methacrylate, benzyl methacrylate, ethoxyphenol acrylate, tetrahydrofurfuryl acrylate, cyclotrimethylolpropane formal acrylate, 4-tert-butylcyclohexyl acrylate, ethoxyethoxyethyl acrylate, diethoxyphenol acrylate, 1,6-hexanediol diacrylate, dipropylene glycol diacrylate, dipropylene glycol diacrylate, diethylene glycol diacrylate At least one of the following: diol diacrylate, dipropoxyneopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, triethoxytrimethylolpropane triacrylate, hexaethoxytrimethylolpropane triacrylate, nonethoxytrimethylolpropane triacrylate, pentadecylethoxytrimethylolpropane triacrylate, tripropoxytrimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, or oligomers thereof; The photoinitiator includes at least one of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 1-hydroxycyclohexylbenzophenone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-(4-methylbenzyl)-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2,4-diethylthiazolinone, and 2-isopropylthioxanthraphenone.

5. The photonic crystal composition based on a dual-curing system according to claim 1, characterized in that... The methyl etherified melamine resin is selected from at least one of Cymel 303LF, Cymel 304, Cymel 308, Cymel 323, Cymel 325, Cymel 327, Cymel 350, Cymel 370, Cymel 373, Cymel 380, and Cymel 385; The n-butyl etherified melamine resin is selected from at least one of Cymel 243-3, Cymel 247-10, and Cymel 1158; The phenyl melamine resin is selected from at least one of Cymel 659, Cymel 1123, and Cymel 5010.

6. A photonic crystal thin film, characterized in that... It includes a plastic substrate layer and a photonic crystal layer directly disposed on the plastic substrate layer, wherein the photonic crystal layer is prepared by curing the photonic crystal composition according to any one of claims 1 to 5, and the nanospheres in the photonic crystal layer are arranged in a three-dimensional ordered manner.

7. A photonic crystal thin film according to claim 6, characterized in that... The plastic substrate layer is selected from at least one of polyethylene terephthalate, polyethylene terephthalate-1,4-cyclohexanediol, polymethyl methacrylate, polyvinyl alcohol, polynaphthalate, polycarbonate, polyurethane, acrylonitrile-butadiene-styrene copolymer, polyvinyl chloride, polyvinylidene fluoride, ethylene-vinyl acetate copolymer, polyvinyl butyral, and polyolefin. The curing process includes photocuring followed by thermal curing.

8. A method for preparing a photonic crystal thin film according to claim 6 or 7, characterized in that... Includes the following steps: Step 1: Mix the nanospheres, acrylate reactants, photoinitiator and thermosetting amino resin evenly to obtain a photonic crystal composition; Step 2: Coat the photonic crystal composition onto a plastic substrate layer and dry it to obtain a composite film; Step 3: The composite film is regularized to ensure that the nanospheres are arranged in a three-dimensional order; Step 4: Perform photocuring treatment on the composite film; Step 5: Perform thermosetting treatment on the composite film.

9. The preparation method according to claim 8, characterized in that... In step one, the acrylate reactants and photoinitiator are mixed evenly, then mixed with nanospheres, stirred evenly, and then amino resin is added to obtain a photonic crystal composition. In step two, the drying is carried out at 50-80°C, and a release layer is then laminated onto the photonic crystal composition to obtain a composite film. In step four, the photocuring process is performed under ultraviolet light, with a cumulative light intensity of not less than 500 mJ / cm². 2 ; In step five, the thermosetting treatment is carried out at 100–150°C.

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