Ultraviolet filter

Abstract

The present invention relates to zinc chalcogenide core-shell nanoparticles having specific light absorption properties, in particular to filtering materials comprising the zinc chalcogenide core-shell nanoparticles.

Description

Technical Field

[0001] This invention relates to the field of zinc chalcogenide core-shell nanoparticles with specific light absorption properties; and to the field of filter materials comprising said zinc chalcogenide core-shell nanoparticles. Background Technology

[0002] As is well known, UV light and blue light, also known as high-energy visible (HEV) light, correspond to visible light in the blue-violet band from 380nm to 450nm, which can have harmful effects on the human body or objects.

[0003] For example, prolonged exposure to blue light emitted by digital devices such as televisions, laptops, tablets, and smartphones, as well as fluorescent and LED lights, can be harmful to the eyes because blue light can reach the retina. Certain ranges of blue light have been shown to cause photoretinitis; digital eyestrain, or computer vision syndrome, including blurred vision, difficulty focusing, dry and inflamed eyes, headaches, neck and back pain; circadian rhythm disruption; reduced melanin production; age-related macular degeneration; glaucoma; and retinal degenerative diseases. Similarly, prolonged exposure to UV light from natural or artificial sources is harmful to the skin and can cause skin discoloration, actinic keratosis, or skin cancers such as basal cell carcinoma, squamous cell carcinoma, or malignant melanoma.

[0004] It is also known and widely observed that the flavor / aroma quality and / or color of certain types of food or cosmetic products may be affected when exposed to light. In the spirits industry, it has been known for centuries that light, especially sunlight, can negatively affect the flavor of many types of spirits. Degradation of color and / or aroma has also been observed in spices and perfumes.

[0005] Various UV filters have been developed in the eyewear, cosmetics, and glass / packaging industries. However, a drawback of conventional UV filters is that they can cause a yellowing effect. This yellowing effect has two sources. First, the filter can degrade under UV irradiation, forming chemical byproducts that have a yellow appearance. Second, the spectral width of the filter transitioning from absorption (in the ultraviolet range) to transparency (in the visible light range) is typically large. Therefore, an effective UV filter must necessarily have residual absorption in the blue range of visible light, causing the human eye to perceive a yellow tint.

[0006] Therefore, there is a need for filter materials used in the manufacture of eyeglasses or glass containers that can effectively filter UV light in the wavelength range of 380 nm to 420 nm, particularly the range of 380 nm to 400 nm, while maintaining extremely low chromaticity. Such achromatic filters allow for the design of eyeglasses with well-defined absorbance spectra that protect the eyes from high-energy radiation and optimize color perception, or the design of white glass containers without the risk of flavor degradation.

[0007] The applicant has discovered that some of these requirements can be met by zinc chalcogenide core-shell nanoparticles with specific light absorption properties, particularly in the 350 nm to 450 nm range. Summary of the Invention

[0008] Therefore, this invention relates to core-shell nanoparticles comprising:

[0009] · ZnSe x S (1-x The material has a core, where x is from 0.80 to 0.98, and the core has:

[0010] - For a core having a nanometer size in one dimension, its thickness is less than 10 nm, preferably less than 5 nm;

[0011] - For a core with a nanometer-sized cross-section in two dimensions, the cross-section is less than 100 nm. 2 Preferably smaller than 50nm 2 ;

[0012] - For a core having a nanoscale size in three dimensions, its diameter is less than 20 nm, preferably less than 15 nm, more preferably less than 10 nm; and

[0013] • A shell of ZnS material, wherein the thickness of the shell is greater than 0.3 nm and less than 5 nm, preferably greater than 0.3 nm and less than 1.5 nm.

[0014] In the implementation scheme, sulfur is distributed in the core in a concentration gradient, preferably with the sulfur concentration at the core center being lower than that at the periphery of the core.

[0015] In the implementation scheme, sulfur is distributed in the outer layer of the core.

[0016] In the implementation scheme, the diameter of the core is less than 20 nm, and x is 0.80 to 0.90. Preferably, the shell thickness is greater than 0.5 nm and less than 3 nm, more preferably greater than 0.6 nm and less than 1.5 nm.

[0017] In this embodiment, the core thickness is less than 10 nm, and x is 0.80 to 0.90. Preferably, the shell thickness is greater than 0.3 nm and less than 3 nm, and more preferably greater than 0.3 nm and less than 1.5 nm.

[0018] In the implementation scheme, the core-shell nanoparticles are embedded in an encapsulation material, preferably in a metal oxide encapsulation material.

[0019] Preferably, the loading of core-shell nanoparticles in the composite particles is at least 1%, preferably at least 2.5%, and more preferably at least 5%, wherein the loading is the mass ratio of the mass of the core-shell nanoparticles contained in the composite particles to the mass of the composite particles.

[0020] Preferably, the average size of the composite particles is 50 nm to 500 nm, more preferably 50 nm to 250 nm.

[0021] The present invention also relates to filter materials comprising a matrix material and at least one group of core-shell nanoparticles or composite particles as disclosed herein.

[0022] In the implementation scheme, the absorbance of the filter material is:

[0023] • It exhibits a local maximum absorbance at wavelengths from 350 nm to 450 nm, with the local maximum value having specific wavelength λ. 最大 Absorbance value A 最大 ,

[0024] • Features specific wavelength λ 0.9 The value is 0.9A 最大 , λ 0.9 Greater than λ 最大 ;

[0025] • Features specific wavelength λ 0.9 The value of +20nm A +20 ;and

[0026] Among them, 0.9A 最大 / A +20 Greater than 25 or equal to 25, preferably greater than 50 or equal to 50, more preferably greater than 100 or equal to 100.

[0027] In the implementation plan, λ 最大 The wavelength is 370nm to 420nm, preferably 375nm to 400nm, and more preferably 380nm to 395nm.

[0028] In one embodiment, the filter material is obtained by curing a polymerizable composition, said polymerizable composition comprising:

[0029] • 0.1% to 10% by weight of zinc sulfide core-shell nanoparticles or composite particles as disclosed herein,

[0030] • 0.1% to 10% by weight of UV-resistant organic compounds,

[0031] • Optional stabilizers and / or antioxidants, and

[0032] • 15% to 40% by weight of polymer matrix material,

[0033] The polymerizable composition has 15% to 70% by weight of dry extract.

[0034] This invention also relates to core-shell nanoparticles, comprising:

[0035] · ZnSe x S( 1-x The material has a core, where x is from 0.60 to 0.98, and the core has:

[0036] - For a core with a nanometer size in one dimension, its thickness is 3 nm to 10 nm;

[0037] - For a core with nanometer-sized dimensions in two dimensions, its cross-section is 9 nm. 2 Up to 100nm 2 ;

[0038] - For cores with nanoscale dimensions in three dimensions, with diameters ranging from 3 nm to 20 nm; and

[0039] • A shell of ZnS material, wherein the thickness of the shell is greater than 0.3 nm and less than 5 nm, preferably greater than 0.3 nm and less than 1.5 nm.

[0040] These particles exhibit higher cutoff wavelengths and are able to absorb UV light and small amounts of visible blue light (up to 450 nm). They are particularly useful for packaging liquids susceptible to UV radiation. For example, these particles can be used in the packaging of polymerizable liquids such as glue or nail polish.

[0041] definition

[0042] In this invention, the following terms have the following meanings:

[0043] "Absorbance" is the decimal logarithm of the ratio I0 / I, where I0 is the intensity of light incident on the sample, and I is the intensity of light transmitted through the sample. In this disclosure, the absorbance of a liquid dispersion of a 2 mm thick sample was measured, and the absorbance of the pure solvent—the absorbance of the blank solvent—was corrected. The absorbance was measured at wavelengths in the UV and visible light range from 350 nm to 780 nm.

[0044] A "core-shell" nanostructure refers to a heterogeneous nanostructure containing an inner portion (core) covered by a layer of material (shell) of at least one atom thickness, different from the core. The core-shell structure is recorded as: Core Material - Shell Material. Core-shell nanostructures also contain nanoparticles in which the central portion (core) is embedded or encapsulated by a layer of material (shell) disposed on the core, the shell having a compositional gradient from the core to the outside of the shell. In this case, the composition of the nanoparticles changes smoothly, as continuously, from the core composition to the outer composition of the shell. There is no precise boundary between the core and the shell, but the properties of the core center differ from those of the outer boundary of the shell. Furthermore, the core and shell can have different shapes; for example, dot-like structures—nanospheres, nanocubes, or any other nanoclusters—are provided as the core, and the shell grows laterally around the core, producing a heterogeneous structure with a nanoplate shape but containing dot-like structures within the nanoplate.

[0045] "Average size" refers to the size of a swarm of particles, obtained by mathematically averaging the size of each individual particle in the swarm. In practice, the average size can be determined using electron microscopy: the size of each visible particle is evaluated by fitting a circle to each particle, the diameter of which defines the particle size; the average size is then calculated by averaging all the individual sizes. Other methods, such as light scattering, can also be used to indirectly determine the average size of a swarm of particles. Experimentally, particles are always obtained as swarms. In this disclosure, by analogy, the average size of the particles is the average size of the synthesized swarms of particles. For clarity, particles with an average size of 100 nm to 250 nm refer to particles representing swarms of particles with an average size of 100 nm to 250 nm.

[0046] "Monodisperse" refers to a group of particles with a polydispersity index (PDI) of size distribution of less than 0.3, preferably less than 0.2.

[0047] "Nanoscale" refers to the size of matter exhibiting quantum effects due to confinement. For semiconductor nanoparticles, nanoscale must be defined by the average Bohr radius of electron / hole pairs. For nanoplates, confinement is effective when the size is less than 10 nm, preferably less than 5 nm, in at least one dimension. For nanorods, the cross-section is less than 100 nm. 2 Preferably smaller than 50nm 2 The time constraint is effective. For nanospheres, a time constraint of less than 20 nm in diameter, preferably less than 15 nm, and more preferably less than 10 nm is effective.

[0048] "Nanoparticles" refer to particles with a size less than 100 nm in at least one dimension. For nanospheres, the diameter should be less than 100 nm. For nanoplates, the thickness should be less than 100 nm. For nanorods, the diameter should be less than 100 nm.

[0049] "Nanoplate" refers to two-dimensional nanoparticles, wherein the smallest dimension—thickness—of the nanoplate is smaller than the largest dimension of the nanoplate, by a multiple (aspect ratio) of at least 1.5, at least 2, at least 2.5, at least 3, at least 3.5, at least 4, at least 4.5, at least 5, at least 5.5, at least 6, at least 6.5, at least 7, at least 7.5, at least 8, at least 8.5, at least 9, at least 9.5, or at least 10. Nanoplates include nanosheets, nanoribbons, or nanodisks.

[0050] "Nanorod" refers to one-dimensional nanoparticles, wherein the average dimension of the cross-section of the nanorod is smaller than the length of the nanorod, and is expressed as a multiple (aspect ratio) of at least 1.5, at least 2, at least 2.5, at least 3, at least 3.5, at least 4, at least 4.5, at least 5, at least 5.5, at least 6, at least 6.5, at least 7, at least 7.5, at least 8, at least 8.5, at least 9, at least 9.5, or at least 10. Nanorods include nanowires and nanorings.

[0051] "Nanospheres" refer to nanoparticles with a three-dimensional shape that have similar dimensions in three directions. Nanospheres also include nanocubes or nanodots.

[0052] "% weight" refers to the weight fraction of a component in a blend or formulation. Detailed Implementation

[0053] Core-shell nanoparticles

[0054] This disclosure relates to ZnSe x S( 1-x Core-shell nanoparticles consisting of a core of a ZnS material and a shell of a ZnS material. The core is rich in selenium, with an x ​​value ranging from 0.80 to 0.98.

[0055] The core is very small, exhibiting a nanoscale size, which leads to the confinement of excitons generated in core-shell nanoparticles. The core can have a nanoscale size in one dimension, and even larger in other dimensions: excitons are confined in only one spatial dimension—see [link to relevant documentation]. Figure 1 Right side. The thickness of this nanoplate core is less than 10 nm, preferably less than 5 nm. The core can have a nanoscale size in two dimensions, and even larger in the third dimension: excitons are confined in two spatial dimensions—see Figure 1 In the middle. The cross-section of this nanorod core is less than 100 nm. 2 Preferably smaller than 50nm 2Finally, the nucleus can have a nanoscale in three dimensions, allowing for exciton confinement in all three spatial dimensions—see Figure 1 Left side. The diameter of this nanosphere is less than 20 nm, preferably less than 15 nm, and more preferably less than 10 nm.

[0056] The thickness of the zinc sulfide (ZnS) shell is greater than 0.3 nm—representing two ZnS monolayers—and less than 5 nm. Preferably, the thickness of the zinc sulfide (ZnS) shell is greater than 0.5 nm and less than 5 nm. More preferably, the thickness of the zinc sulfide (ZnS) shell is greater than 0.6 nm and less than 1.5 nm.

[0057] The size and composition of core-shell nanoparticles define semiconductor nanoparticles with band gaps that allow absorption of light in the UV range. In fact, light with wavelengths higher than the band gap can be absorbed by semiconductor materials, generating electron / hole pairs, excitons, which subsequently recombine within the material and dissipate heat, emit light, or both. Conversely, light with wavelengths lower than the band gap energy cannot be absorbed: semiconductor materials are transparent to these wavelengths. Ultimately, the semiconductor material behaves as a high-pass filter. When semiconductor particles have nanoscale dimensions, constraints—i.e., shape and nanoscale size—follow the rules of quantum mechanics to control the electronic structure, and light absorption can be limited to the UV range or to both UV and high-energy visible light. In this disclosure, the semiconductor nanoparticles absorb light with wavelengths below a threshold, which is 350 nm to 450 nm.

[0058] Furthermore, simple ZnSe nanoparticles—nanospheres, nanorods, or nanoplates—typically degrade under light when contained in organic matrices such as varnishes or coatings. Without being bound by theory, the applicant believes that well-dispersed organic compositions of ZnSe nanoparticles can extract some selenium atoms and potentially alter their oxidation state, resulting in organoselenium compounds with a residual yellow color. The addition of a ZnS shell provides protection against this phenomenon, but zinc selenide and zinc sulfide have slightly different crystal structures, and better performance is obtained when the core is doped with sulfur.

[0059] The distribution of sulfur within the core of core-shell nanoparticles can be uniform or non-uniform.

[0060] According to the implementation scheme, sulfur is distributed in the core in a concentration gradient. Preferably, the sulfur concentration at the core center is lower than the sulfur concentration at the periphery. The periphery is rich in sulfur, which makes it better matched with the crystal structure of the zinc sulfide shell, thus making the zinc sulfide shell easier to deposit.

[0061] According to the embodiment, sulfur is distributed in the outer layer of the core. In this embodiment, the core comprises a central portion having a composition of zinc selenide (ZnSe) and an outer layer surrounding the central portion. The outer layer has a zinc selenide sulfide composition (ZnSe). x S(1-x Furthermore, the overall atomic percentage of selenium ions in the entire nucleus is 60 to 98 atomic percent—the atomic percentage of chalcogens in the nucleus does not include zinc. Suitable core-shell nanoparticles can be produced using the formula ZnSe / ZnSe. x S( 1-x ) / ZnS indicates that the core is ZnSe / ZnSe x S( 1-x The diameter of the central portion of the core is preferably 2 nm to 7 nm, the thickness of the outer core layer is preferably 0.3 nm to 3 nm, and the thickness of the zinc sulfide shell is preferably 0.3 nm to 3 nm. Core-shell nanoparticles with a central core diameter of 3 nm, an outer core thickness of 1.5 nm, and a zinc sulfide shell thickness of 1.5 nm are particularly suitable.

[0062] According to the implementation scheme, selenium is distributed in the outer layer of the core. In this implementation scheme, the core comprises a central portion having a composition of zinc sulfide (ZnS) and an outer layer surrounding the central portion. The outer layer has a zinc selenide composition (ZnSe). x S( 1-x Furthermore, the overall atomic percentage of selenium ions in the entire nucleus is 60 to 98 atomic percent—the atomic percentage of chalcogens in the nucleus does not include zinc. Suitable core-shell nanoparticles can be produced using the formula ZnS / ZnSe. x S( 1-x ) / ZnS indicates that the core is ZnS / ZnSe. x S( 1-x ).

[0063] In the embodiments, the core-shell nanoparticles are nanospheres, wherein the diameter of the core is less than 20 nm and x is 0.70 to 0.95. Preferably, the shell thickness is greater than 0.5 nm and less than 3 nm, more preferably greater than 0.6 nm and less than 1.5 nm. Nanosphere core-shell nanoparticles with a core diameter of 3.5 nm and a zinc sulfide shell thickness of 1.5 nm are particularly suitable.

[0064] In one embodiment, the core-shell nanoparticles are nanoplates, wherein the core thickness is less than 10 nm and x is 0.70 to 0.95. Preferably, the shell thickness is greater than 0.5 nm and less than 3 nm, more preferably greater than 0.6 nm and less than 1.5 nm. In a preferred embodiment, the core thickness is less than 5 nm, x is 0.70 to 0.95, and the shell thickness is greater than 0.5 nm and less than 3 nm.

[0065] In one embodiment, the core-shell nanoparticles may be coated on their surface with a layer of material different from the core and / or shell, at least one atom thick, thereby creating core / first shell / second shell nanoparticles. The preferred composition of the second shell is zinc oxide. The preferred thickness of the second shell is 0.25 nm to 10 nm. Suitable core-shell nanoparticles can be made from the formula ZnSe. x S( 1-x ) / ZnS / ZnO represents this.

[0066] This disclosure also relates to core-shell nanoparticles, which comprise:

[0067] · ZnSe x S( 1-x The material has a core, where x is from 0.60 to 0.98, and the core has:

[0068] - For a core with a nanometer size in one dimension, its thickness is 3 nm to 10 nm;

[0069] - For a core with nanometer-sized dimensions in two dimensions, its cross-section is 9 nm. 2 Up to 100nm 2 ;

[0070] - For cores with nanoscale dimensions in three dimensions, with diameters ranging from 3 nm to 20 nm; and

[0071] • A shell of ZnS material, wherein the thickness of the shell is greater than 0.3 nm and less than 5 nm, preferably greater than 0.3 nm and less than 1.5 nm.

[0072] In another embodiment, the core-shell nanoparticles comprise:

[0073] · ZnSe x S( 1-x The material has a core, where x is from 0.60 to 0.98, and the core has:

[0074] - For a core with a nanometer size in one dimension, its thickness is 4 nm to 10 nm;

[0075] - For a core with nanometer-sized dimensions in two dimensions, its cross-section is 16 nm. 2 Up to 100nm 2 ;

[0076] - For cores with nanoscale dimensions in three dimensions, with diameters ranging from 4 nm to 20 nm; and

[0077] • A shell of ZnS material, wherein the thickness of the shell is greater than 0.3 nm and less than 5 nm, preferably greater than 0.3 nm and less than 1.5 nm.

[0078] All core-shell nanoparticles disclosed above are compatible with the following description of composite particles.

[0079] Composite particles

[0080] This disclosure also relates to composite particles comprising the core-shell nanoparticles disclosed herein, wherein the core-shell nanoparticles are embedded in an encapsulating material. The encapsulating material is a material covering all surfaces of the zinc sulfide core-shell nanoparticles. In other words, the encapsulating material forms a barrier around the nanoparticles. This barrier has several advantages. In particular, the nanoparticles can be protected from chemicals such as moisture and oxidants. Furthermore, zinc sulfide core-shell nanoparticles that cannot be dispersed in a medium can be encapsulated in a material compatible with the medium: the barrier acts as a compatibilization agent. Additionally, the encapsulated zinc sulfide core-shell nanoparticles can be in the form of a powder that can be dispersed in a medium, rather than a dispersion in a solvent, thus providing easier handling in existing methods. Finally, the encapsulating material can have a refractive index matching effect to reduce diffusion or haze: in fact, when core-shell nanoparticles are dispersed in a matrix, haze is proportional to the difference in refractive index between the matrix and the dispersed nanoparticles. Adding an encapsulating material with an intermediate refractive index mitigates this effect and reduces haze.

[0081] The encapsulation material can be organic, especially organic polymers. Alternatively, the encapsulation material can be inorganic, such as metal oxides or mixtures of metal oxides. Suitable metal oxides include SiO2, Al2O3, TiO2, ZrO2, FeO, ZnO, MgO, SnO2, Nb2O5, CeO2, BeO, IrO2, CaO, Sc2O3, Na2O, BaO, K2O, TeO2, MnO, B2O3, GeO2, As2O3, Ta2O5, Li2O, SrO, Y2O3, HfO2, MoO2, Tc2O7, ReO2, Co3O4, OsO, RhO2, Rh2O3, CdO, HgO, Tl2O, Ga2O3, In2O3, Bi2O3, Sb2O3, PoO2, SeO2, Cs2O, La2O3, and Pr6O. 11 Nd₂O₃, La₂O₃, Sm₂O₃, Eu₂O₃, Tb₄O₇, Dy₂O₃, Ho₂O₃, Er₂O₃, Tm₂O₃, Yb₂O₃, Lu₂O₃, Gd₂O₃, or mixtures thereof. Preferred metal oxides are SiO₂, Al₂O₃, TiO₂, ZrO₂, HfO₂, GeO₂, SnO₂, or mixtures thereof, including, for example... Al y Zr z O. In the implementation scheme, the encapsulating material is not composed of pure SiO2.

[0082] In the embodiments, the loading of core-shell nanoparticles in the composite particles is at least 1%, preferably at least 2.5%, and more preferably at least 5%, where the loading is the mass ratio of the mass of the core-shell nanoparticles contained in the composite particles to the mass of the composite particles themselves. In fact, the performance of the composite particles is proportional to the concentration of core-shell nanoparticles they contain. Therefore, a high concentration of core-shell nanoparticles is advantageous. However, it must be noted that increasing the concentration of core-shell nanoparticles without reducing their performance—for example, as a result of aggregation or manufacturing processes—is not easy.

[0083] Composite particles can be in the form of monodisperse clusters. Monodisperse composite particles are advantageous for various reasons, depending on the application. When composite particles are used in optical components—particularly filters—the uniform size distribution avoids uncontrolled light stenosis and ensures the spatial uniformity of the optical components.

[0084] The average size of the composite particles is preferably from 50 nm to 500 nm, more preferably from 50 nm to 250 nm. Composite particles with an average size of 50 nm to 250 nm, preferably from 50 nm to 100 nm, are particularly suitable filter materials with high transparency and low haze.

[0085] Composite particles can be chemically modified on their surface. Chemical modification can be achieved through grafting, molecular adsorption, or physical methods—heating, vacuum treatment, or gas treatment. Compatibilizers can be used with chemical modification, allowing composite particles to be mixed in complex formulations—such as resins, varnishes, coatings, colloidal dispersions, etc.—without causing aggregation or phase separation of the composite particles.

[0086] Filter materials

[0087] This disclosure also relates to filter materials comprising a matrix material and at least one group of core-shell nanoparticles as disclosed herein—encapsulated or unencapsulated in the form of composite particles.

[0088] The matrix can be obtained by curing a polymerizable composition, provided that the polymerizable composition is sufficiently transparent to visible light and allows for the dispersion of core-shell nanoparticles. Suitable polymerizable compositions comprise monomers or oligomers selected from allyl compounds, (meth)acrylic compounds, epoxy compounds, compounds used to prepare polyurethane or polythiourethane materials, compounds used to prepare polyester-melamine compounds, and compounds used to prepare melamine-formaldehyde resins. Mixtures of these compounds—particularly epoxy / acrylic mixtures or polyester-melamine / melamine-formaldehyde mixtures—are also suitable. Furthermore, compounds used to prepare materials commonly referred to as sol-gels are also suitable as polymerizable compositions.

[0089] A particularly suitable matrix is ​​a waterborne polyester-melamine coating made of saturated polyester containing an increased amount of carboxyl groups, having an acid value of 45 mg KOH / g to 55 mg KOH / g and a molecular weight of about 2000 g / mol. The polyester is combined with a water-soluble melamine-formaldehyde resin, such as hexamethylolmelamine, at a weight ratio of polyester 70: melamine-formaldehyde 30 to polyester 85: melamine-formaldehyde 15.

[0090] In this embodiment, the amount of core-shell nanoparticles in the matrix is ​​from 10 ppm to 1% by weight, particularly from 20 ppm to 0.5% by weight, and even more particularly from 25 ppm to 0.25% by weight, based on the weight of the filter material. This embodiment is particularly suitable for thick films with a thickness greater than 50 µm.

[0091] In this embodiment, the amount of core-shell nanoparticles in the matrix is ​​from 1% to 30% by weight, particularly from 3% to 25% by weight, and even more particularly from 5% to 20% by weight, based on the weight of the filter material. This embodiment is particularly suitable for films with a thickness of less than 20 µm.

[0092] The characteristic of filter materials lies in their absorbance, such as Figure 2 As shown. Since zinc chalcogenide core-shell nanoparticles are semiconductors, they impart high-pass properties to the filter material. More precise observation of the absorption spectrum reveals localized absorbance maxima in the 350 nm to 450 nm range. These local maxima are specific to wavelength λ. 最大 It has an absorbance value A 最大 Zinc sulfide core-shell nanoparticles exhibit a very abrupt transition from a highly absorbent state to a non-absorbent state. This transition is defined as follows: [The value is greater than λ]. 最大 The next wavelength, at which the absorbance is 0.9 Å. 最大 —that is, A 最大 90% of the value is defined as λ 0.9 Then, the wavelength λ is measured. 0.9 The absorbance at +20nm is defined as A. +20 Therefore, 0.9A 最大 / A +20 The ratio defines the relative decrease in absorbance above 20 nm. It is important to note that absorbance is calculated on a logarithmic base-10 basis. This means that the decrease in transmittance of the filter material is even more significant.

[0093] For conventional organic filters with a typical absorption peak full width at half maximum (FWHM) of 80 nm to 100 nm, this ratio is approximately a few units.

[0094] According to this disclosure, 0.9A 最大 / A+20 The ratio is greater than or equal to 25. Preferably, 0.9A 最大 / A +20 The ratio is greater than or equal to 50. More preferably, 0.9A 最大 / A +20 The ratio is greater than or equal to 100.

[0095] In the implementation scheme, wavelength λ 最大 The wavelength range is 370 nm to 420 nm, preferably 375 nm to 400 nm, and more preferably 380 nm to 395 nm. Within this range, the filter material strongly absorbs UV light—defined as light with wavelengths less than 380 nm—and optionally high-energy visible light, typically up to 400 nm. However, wavelengths greater than 410 nm—for λ 最大 Approximately 380nm—or greater than 420nm—for λ 最大 Visible light at approximately 390 nm is not absorbed at all. Ultimately, this filter effectively protects against UV and / or HEV light without filtering out blue light, which contributes to color perception. In other words, color perception remains unchanged after passing through this filter material, while UV and / or HEV light is absorbed.

[0096] additive

[0097] In addition to core-shell zinc sulfide nanoparticles, various additives can be added to the filter material.

[0098] In the implementation scheme, the filter material also contains an organic UV-resistant compound. Suitable UV-resistant compounds are benzotriazoles, especially derivatives of (2H-benzotriazol-2-yl)-4-hydroxyphenyl, such as sodium 3-(2H-benzotriazol-2-yl)-5-sec-butyl-4-hydroxybenzenesulfonate (CAS No. 92484-48-5), polyethylene glycol mono-3-(3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl)-1-oxopropyl ether (CAS No. 104810-48-2), or polyethylene glycol di[3-[3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl]-1-oxopropyl] ether. di[3-[3-(2H-benzotriazol-2-yl)-5-tert-butyl-4-hydroxyphenyl]-1-oxopropyl] ether)—CAS No. 104810-47-1—or Benzenepropanoic acid, C7-9 branched and linear alkyl esters of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-esters. esters)—CAS number is 127519-17-9—or 2-(2H-benzotriazol-2-yl)-6-(1-methyl-1-phenylethyl)-4-(1,1,3,3-tetramethylbutyl)phenol—CAS number is 73936-91-1.Other suitable UV-resistant compounds are triazines, such as the reaction product of 4-[4,6-bis(2,4-dimethylphenyl)-1,3,5-triazin-2-yl]-1,3-benzenediol with [(dodecoxy)methyl]ethylene oxide and ethylene oxide mono[(C10 to C16 alkoxy)methyl] derivatives—CAS No. 153519-44-9—or 6-methylheptyl-2-[4-[4,6-bis[(1,1'-biphenyl)-4-yl]-1,3,5-triazin-2-yl]-3-hydroxyphenoxy]propanoate—CAS No. 204848-45-3—or TINUVIN, provided by BASF. ® 477 Triazine. Other suitable UV-resistant compounds are avobenzone compounds, such as 1-[4-(1,1-dimethylethyl)phenyl]-3-(4-methoxyphenyl)-1,3-propanedione—CAS No. 70356-09-1.

[0099] In the implementation scheme, the filter material also contains a stabilizer. Suitable stabilizers are hindered amine light stabilizers—HALS compounds—such as bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate—CAS No. 41556-26-7—or methyl(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate—CAS No. 82919-37-7—or bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl) sebacate—CAS No. 129757-67-1—or The reaction product of 2-aminoethanol with cyclohexane and N-butyl-2,2,6,6-tetramethyl-4-piperidinamine-2,4,6-trichloro-1,3,5-triazine peroxide—CAS No. 191743-75-6—or bis(1,2,2,6,6-pentamethyl-4-piperidinyl)-2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate—CAS No. 63843-89-0—or Tinuvin provided by BASF. ® 249.

[0100] Specific mixtures of additives are also suitable, such as blends of polyethylene glycol with CAS numbers 104810-48-2, 104810-47-1, 41556-26-7, and 82919-37-7, or blends of benzotriazole with HALS (CAS number 127519-17-9). The trade name TINUVIN is available from BASF. ® 5050, TINUVIN ®5060, TINUVIN ® 5151 or TINUVIN ® The products from 5333DW are also suitable.

[0101] In the implementation scheme, the filter material also contains an antioxidant or oxygen scavenger, such as IRGANOX, a product offered by BASF. ® A series of products.

[0102] In the implementation scheme, the filter material also contains a cosolvent, such as short-chain alcohols—especially propanol or butanol—ketones—especially butanone, methyl ethyl ketone or γ-butyrolactone—or glycols—especially ethylene glycol or diethylene glycol butyl ether—or esters—especially butyl acetate—or polar solvents such as dimethyl sulfoxide (DMSO) or xylene.

[0103] The filter material is preferably obtained by curing a polymerizable composition, said polymerizable composition comprising:

[0104] • 0.1% to 10% by weight of the zinc chalcogenide core-shell nanoparticles disclosed herein,

[0105] • 0.1% to 10% by weight of UV-resistant organic compounds,

[0106] • Optional stabilizers and / or antioxidants, and

[0107] • 15% to 40% by weight of polymeric matrix material,

[0108] The polymerizable composition has 15% to 70% by weight of dry extract.

[0109] Preferably, the polymerizable composition is an aqueous polymerizable composition.

[0110] In some embodiments, the filter material is obtained by curing a polymerizable composition that also contains 0.1% to 5% by weight of a stabilizer.

[0111] When blends of UV-resistant organic compounds and stabilizers are used, weight composition refers to the individual components of the blend.

[0112] In some embodiments, the filter material is obtained by curing a polymerizable composition that also contains 0.1% to 5% by weight of an antioxidant or oxygen scavenger.

[0113] A light-filtering material with an improved balance between UV absorption, weather resistance, and low colorfastness is obtained by curing a polymerizable composition, said polymerizable composition comprising:

[0114] • 2% to 8% by weight of the zinc sulfide core-shell nanoparticles disclosed herein,

[0115] • 2% to 8% by weight of UV-resistant organic compounds,

[0116] • Optional stabilizers and / or antioxidants, and

[0117] • 15% to 40% by weight of polymer matrix material,

[0118] The polymerizable composition has 20% to 60% by weight of dry extract.

[0119] Blend of core-shell zinc sulfide particles

[0120] Filter materials can contain a mixture of different core-shell zinc sulfide particles to fine-tune optical properties, particularly the balance between UV absorption and residual color of the filter material.

[0121] Blends may contain size—for core and shell—and / or composition—the core parameter x—different core-shell zinc chalcogenide particles.

[0122] The blend may contain core-shell zinc sulfide particles directly dispersed in the matrix material or composite particles containing core-shell zinc sulfide nanoparticles. Attached Figure Description

[0123] Figure 1 These are schematic diagrams—cross-sectional views—of core-shell zinc chalcogenide nanoparticles of different shapes: nanospheres (left), nanorods (middle), and nanoplates (right). The composition is ZnSe. x S( 1-x The core of ZnS is represented by a shaded surface. The shell of ZnS is represented by a dotted surface. Arrows on each shape indicate the nanoscale size of the core-shell zinc chalcogenide nanoparticles.

[0124] Figure 2 This illustrates the transition from a highly absorbent state to a non-absorbent state, and how to evaluate parameter A. 最大 , λ 最大 , λ 0.9 A +20 and λ 0.9 The chart for +20nm: Absorbance A (vertical axis, logarithmic scale, arbitrary units) as a function of wavelength (λ, in nm).

[0125] Figure 3This is a graph showing the absorbance A (vertical axis, logarithmic scale, arbitrary units) of different particles as a function of wavelength (λ, in nm). The solid line corresponds to Example 1 using zinc chalcogenide core-shell nanoparticles. The double dashed line corresponds to Example 2 using zinc chalcogenide core-shell nanoparticles. The dashed line corresponds to the comparative example using ZnSe nanoparticles.

[0126] Example

[0127] The present invention is further illustrated by the following embodiments.

[0128] Example 1:

[0129] 5.9 g of zinc stearate (zinc precursor for the core), 136 g of N-dodecyl-N'-phenylthiourea (sulfur precursor for the core), 2.07 g of N,N,N'-tricyclohexylselenourea (selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 260 °C and held for 15 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. The mixture was then cooled to room temperature, and 10.6 g of zinc stearate (zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 280 °C. During the heating process, 20 mL of 1.0 M trioctylphosphine sulfide (TOPS, sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and maintaining the mixture at 280°C for 2 hours, the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have the formula ZnSe with an average diameter of 3.0 nm and x approximately 0.94. x S( 1-x The core and shell with an average thickness of 1.3 nm.

[0130] The absorbance of a dispersion of 2 mg core-shell nanospheres in 3 mL heptane was measured using a Jasco V770 UV-Vis-NIR instrument in 1 nm increments and reported. Figure 3 (Solid line). Absorbance shows a maximum value A at 403 nm. 最大 =0.41. For λ 0.9 =406.5nm, absorbance observed was 0.9A 最大 =0.37. And in λ 0.9 The absorbance at +20 = 426.5 nm is A. +20 =0.0029. 0.9A 最大 / A +20The ratio is estimated to be 124. Absorbance decreases by more than two orders of magnitude within 20 nm: absorption is almost complete at 403 nm and almost no absorption is observed at 426.5 nm.

[0131] 40 mg of core-shell nanospheres were mixed in alkaline water into a polymerizable composition of aqueous polyester resin (75 parts) and hexamethylol melamine (25 parts), and applied to a glass substrate. After curing, a 10 µm thick coating was produced, with a core-shell nanosphere concentration of 75 ppm.

[0132] The coating aging was carried out under the following conditions: constant illumination corresponding to a D65 light source, with a total power of 500W / m over 8 hours. 2 —It is called SUNTEST. No obvious yellowing was observed after aging.

[0133] Example 2:

[0134] Example 1 was repeated on a larger scale in a 10L reactor. The obtained nanospheres had an average core diameter of 2.8 nm and an average shell thickness of 1.2 nm.

[0135] The absorbance of a dispersion of 2 mg core-shell nanospheres in 3 mL heptane was measured using a Jasco V770 UV-Vis-NIR instrument in 1 nm increments and reported. Figure 3 (Double underline). Absorbance shows a maximum value A at 383 nm. 最大 =0.42. For λ 0.9 An absorbance of 0.9 Å was observed at 389 nm. 最大 =0.38. And in λ 0.9 The absorbance at +20 = 409 nm is A. +20 =0.0145. 0.9A 最大 / A +20 The ratio is estimated to be 26. The large-scale production of core-shell nanospheres has led to different sizes—proven by the shift of the band gap to lower wavelengths—and greater dispersion in size and structure, resulting in a wider transition region between almost complete absorption and almost no absorption.

[0136] 40 mg of core-shell nanospheres were mixed in alkaline water into a polymerizable composition of aqueous polyester resin (75 parts) and hexamethylol melamine (25 parts), and applied to a glass substrate. After curing, a 10 µm thick coating was produced, with a core-shell nanosphere concentration of 75 ppm.

[0137] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0138] Example 3:

[0139] 360 mg of zinc nitrate (a zinc precursor for the core), 6 mg of sulfur, 270 mg of selenium, 40 mL of oleylamine, and 20 mL of octylamine were mixed in a 100 mL round-bottom flask. After vacuum degassing, the mixture was heated to 180 °C and held for 35 minutes under a nitrogen stream and magnetic stirring to synthesize a zinc sulfide core. Then, 2 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, leading to shell formation. After TOPS injection, the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core of the core-shell nanoparticles had an average thickness of 1.4 nm—lateral dimensions of approximately 20 nm wide and 60 nm long—and was expressed as x = approximately 0.85 ZnSe. x S( 1-x ), and the average thickness of the shell is 1 nm.

[0140] Similar absorption characteristics as in Example 1 were observed.

[0141] 40 mg of core-shell nanoplates were mixed in alkaline water into a polymerizable composition of waterborne polyester resin (75 parts) and hexamethylol melamine (25 parts), and applied to a glass substrate. After curing, a 10 µm thick coating was produced, with a core-shell nanoplate concentration of 75 ppm.

[0142] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0143] Example 4:

[0144] 136 mg of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the nucleus), 2.07 g of N,N,N'-tricyclohexylselenourea (a selenium precursor for the nucleus), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 260 °C and held for 10 minutes under a nitrogen stream and magnetic stirring. Then, 2.15 mg of zinc stearate (a zinc precursor for the nucleus) was added, and heating was continued for an additional 5 minutes. A ZnSe / ZnSe ratio was obtained. x S( 1-x The core-shell nanoparticles were then formed by adding a zinc sulfide core with a ZnSe / ZnSe structure. The mixture was then cooled to room temperature, and 10.6 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 280 °C. During the heating process, 20 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and maintaining the mixture at 280 °C for 2 hours, the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles possessed a ZnSe / ZnSe structure. x S( 1-xThe core has a ZnSe / ZnS structure. The average diameter of the central region is 2.4 nm, the thickness of the outer layer is 1 nm, and the overall core structure is ZnSe with x = approximately 0.95. x S( 1-x ), and the average thickness of the shell is 1.3 nm.

[0145] Similar absorption characteristics as in Example 1 were observed.

[0146] 40 mg of core-shell nanospheres were mixed in alkaline water into a polymerizable composition of aqueous polyester resin (75 parts) and hexamethylol melamine (25 parts), and applied to a glass substrate. After curing, a 10 µm thick coating was produced, with a core-shell nanosphere concentration of 75 ppm.

[0147] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0148] Example 5:

[0149] 40 mg of the core-shell nanoplates prepared according to Example 1 were mixed with 50 mg of TINOGARD in water:DMSO (weight ratio 6:1). ® HS (supplier BASF, CAS number 92484-48-5), 30mg TINUVIN ® A blend of 292 (supplier BASF, CAS No. 41556-26-7) and 0.7 g of waterborne polyester resin (85 parts) – hexamethylolmelamine (15 parts) was mixed and cured to produce a polymer matrix. The composition had a dry content of 65% by weight. The polymerizable composition was applied to a glass substrate, and after curing, a 10 µm thick coating was formed.

[0150] Similar absorption characteristics as in Example 1 were observed.

[0151] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0152] Example 6:

[0153] 40 mg of the core-shell nanoplates prepared according to Example 4 were mixed with 40 mg of TINUVIN in a water:DMSO (weight ratio 6:1). ® 1130 (supplier BASF, CAS number 104810-48-2), 20mg TINUVIN ® A blend of 249g (supplier BASF) and 0.6g of waterborne polyester resin (85 parts) – hexamethylolmelamine (15 parts) was mixed and cured to produce a polymer matrix. The composition had a dry content of 60% by weight. The polymerizable composition was applied to a glass substrate, and after curing, a 10µm thick coating was formed.

[0154] Similar absorption characteristics as in Example 4 were observed.

[0155] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0156] Example 7:

[0157] 40 mg of the core-shell nanoplates prepared according to Example 1 were mixed with 32 mg of TINUVIN in a water:DMSO (weight ratio 6:1). ® 9945DW (supplier BASF, CAS No. 127519-17-9), 40mg TINUVIN ® A blend of 144 (supplier BASF, CAS No. 63843-89-0) and 0.8 g of waterborne polyester resin (85 parts) – hexamethylolmelamine (15 parts) was mixed and cured to produce a polymer matrix. The composition had a dry content of 67% by weight. The polymerizable composition was applied to a glass substrate, and after curing, a 10 µm thick coating was formed.

[0158] Similar absorption characteristics as in Example 1 were observed.

[0159] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0160] Example 8:

[0161] 40 mg of the core-shell nanoplates prepared according to Example 4 were mixed with 50 mg of TINUVIN in a water:DMSO (weight ratio 6:1). ® 384-2 (supplier BASF, CAS number 127519-17-9), 40mg TINUVIN ® A blend of 152 (supplier BASF, CAS No. 191743-75-6) and 0.55 g of waterborne polyester resin (85 parts) – hexamethylolmelamine (15 parts) was mixed and cured to produce a polymer matrix. The composition had a dry content of 55% by weight. The polymerizable composition was applied to a glass substrate, and after curing, a 10 µm thick coating was formed.

[0162] Similar absorption characteristics as in Example 4 were observed.

[0163] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0164] Example 9:

[0165] 25 mg of the core-shell nanoplatelets prepared according to Example 1 and 15 mg of the core-shell nanoplatelets prepared according to Example 4 were mixed with 20 mg of TINUVIN in water:DMSO (weight ratio 6:1). ® 1130 (supplier BASF, CAS number 104810-48-2), 20mg TINUVIN ® 9945DW (supplier BASF, CAS No. 127519-17-9), 40mg TINUVIN ® A blend of 152 (supplier BASF, CAS No. 191743-75-6) and 0.65 g of waterborne polyester resin (85 parts) – hexamethylolmelamine (15 parts) was mixed and cured to produce a polymer matrix. The composition had a dry content of 65% by weight. The polymerizable composition was applied to a glass substrate, and after curing, a 10 µm thick coating was formed.

[0166] Similar absorption characteristics as in Example 4 were observed.

[0167] The coating was aged under SUNTEST conditions. No significant yellowing was observed after aging.

[0168] Example 10:

[0169] 5.69 g of zinc stearate (a zinc precursor for the core), 250 mg of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the core), 412 mg of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 230 °C and held for 90 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. The mixture was then cooled to room temperature, and 7.95 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 260 °C. During the heating process, 20 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 260 °C for 3 hours, 24 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 3.0 nm and an x-value of approximately 0.94, and are of the ZnSe formula. x S( 1-x The core and the shell with an average thickness of 0.8 nm.

[0170] Example 11:

[0171] 17.07 g of zinc stearate (a zinc precursor for the core), 1.04 g of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the core), 1.17 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 220 °C and held for 90 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. The mixture was then cooled to room temperature, and 21.5 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 250 °C. During the heating process, 54 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 250 °C for 3 hours, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were ultimately dispersed in heptane. The core-shell nanoparticles have an average diameter of 3.5 nm and an x-value of approximately 0.90, resulting in a ZnSe group. x S( 1-x The core and shell with an average thickness of 0.7 nm.

[0172] Example 12:

[0173] 29.08 g of zinc stearate (a zinc precursor for the core), 1.83 g of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the core), 2.46 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 220 °C and held for 30 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. 37.26 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 260 °C. During the heating process, 93 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 260 °C for 30 min, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 6.0 nm and an x-value of approximately 0.88, and are of the ZnSe formula. x S( 1-x The core and shell with an average thickness of 0.9 nm.

[0174] Example 13:

[0175] 29.08 g of zinc stearate (a zinc precursor for the core), 1.83 g of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the core), 2.45 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed and dissolved in the aforementioned solution. The solution was then pumped at a flow rate of 0.75 mL / min using an HPLC pump and placed in an oven heated to 220 °C with the delivery tubes in the oven. The cores were collected in a round-bottom flask. 37.2 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 250 °C. During the heating process, 93 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, leading to shell formation. After injecting TOPS and maintaining the temperature at 250 °C for 3 hours, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were then finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 2.8 nm and a ZnSe morphology of approximately 0.97. x S( 1-x The core and shell with an average thickness of 0.7 nm.

[0176] Example 14:

[0177] 50 g of zinc stearate (a zinc precursor for the core), 2.25 g of N-dodecyl-N'-phenylthiourea (a sulfur precursor for the core), 3.71 g of selenium powder (a selenium precursor for the core), and 360 mL of octadecene were mixed in a 1-liter reactor. After vacuum degassing, the mixture was heated to 230 °C and held for 30 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. The mixture was then cooled to room temperature, and 51.21 g of zinc stearate (a zinc precursor for the shell) was introduced into a flask. The mixture was then heated to 260 °C. During the heating process, 126 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 260 °C for 30 min, 150 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were ultimately dispersed in heptane. The core-shell nanoparticles have an average diameter of 9.3 nm and an x-value of approximately 0.81, resulting in a ZnSe group. x S( 1-x The core and the shell with an average thickness of 0.8 nm.

[0178] Example 15:

[0179] 17.07 g of zinc stearate (a zinc precursor for the core), 3.23 mL of dodecanethiol, 1.42 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 220 °C and held for 90 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. The mixture was then cooled to room temperature, and 21.5 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 250 °C. During the heating process, 54 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 250 °C for 3 hours, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 7.0 nm and an x-value of approximately 0.91, and are of the ZnSe formula. x S( 1-x The core and the shell with an average thickness of 0.8 nm.

[0180] Example 16:

[0181] 29.08 g of zinc stearate (a zinc precursor for the core), 5.6 mL of dodecanethiol, 2.45 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed in a round-bottom flask. After degassing under vacuum, the mixture was heated to 220 °C and held for 90 min under a nitrogen stream and magnetic stirring to synthesize the zinc sulfide core. 37.2 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 250 °C. During the heating process, 93 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, resulting in shell formation. After injecting TOPS and holding at 250 °C for 3 hours, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 2.7 nm and an x-value of approximately 0.96, and are of the ZnSe formula. x S( 1-x The core and shell with an average thickness of 0.7 nm.

[0182] Example 17:

[0183] 29.08 g of zinc stearate (a zinc precursor for the core), 5.6 mL of dodecanethiol, 2.45 g of selenium powder (a selenium precursor for the core), and 120 mL of octadecene were mixed and dissolved in the aforementioned solution. The solution was then pumped at a flow rate of 0.75 mL / min using an HPLC pump and placed in an oven heated to 250 °C. The oven included tubing for delivering the solution. The cores were collected in a round-bottom flask. 37.2 g of zinc stearate (a zinc precursor for the shell) was introduced into the flask. The mixture was then heated to 250 °C. During the heating process, 93 mL of 1.0 M trioctylphosphine sulfide (TOPS, a sulfur precursor for the shell) was added dropwise, leading to shell formation. After injecting TOPS and maintaining the temperature at 250 °C for 3 hours, 72 mL of oleic acid was added, and the mixture was cooled to room temperature. The obtained core-shell nanoparticles were purified by adding isopropanol and centrifuging twice. The core-shell nanoparticles were finally dispersed in heptane. The core-shell nanoparticles have an average diameter of 3.2 nm and an x-value of approximately 0.92, and are of the ZnSe formula. x S( 1-x The core and the shell with an average thickness of 0.8 nm.

[0184] Comparative example:

[0185] Example 1 was repeated, but without shell deposition on the nanoparticles. The final result was ZnSe with an x ​​of approximately 0.94 and an average diameter of 3 nm. x S( 1-x Zinc sulfide nanospheres.

[0186] The absorbance of a dispersion of 2 mg nanospheres in 3 mL heptane was measured using a Jasco V770 UV-Vis-NIR instrument in 1 nm increments and reported. Figure 3 (Dashed line). Absorbance shows a maximum value A at 370 nm. 最大 =0.49. For λ 0.9 =375nm, absorbance observed was 0.9A 最大 =0.43. And in λ 0.9 The absorbance at +20 = 395nm is A. +20 =0.0214. 0.9A 最大 / A +20 The ratio is estimated to be 20.

[0187] 40 mg of nanospheres were mixed in alkaline water into a polymerizable composition of waterborne polyester resin (75 parts) and hexamethylol melamine (25 parts), and then applied to a glass substrate. After curing, a 10 µm thick coating was produced, with a nanosphere concentration of 75 ppm.

[0188] The coating was aged under SUNTEST conditions. A slight yellowing appeared after aging. Compared to core-shell nanospheres, the shell-less nanospheres are more easily degraded.

[0189] ZnSe x S( 1-x Comparison of nuclear diameters

[0190] The following shows the ZnSe x S( 1-x The nuclear radius of quantum dots composed of different components.

[0191]

[0192] It has been observed that ZnSe x S( 1-x The higher the sulfur content in the quantum dot nucleus, the lower the maximum absorption wavelength. Conversely, the larger the quantum dot, the higher the maximum absorption wavelength. Therefore, targeting a constant maximum absorption wavelength of 400 nm to 450 nm, ZnSe... x S( 1-x The higher the sulfur content in the nucleus, the larger the quantum dot should be.

[0193] Furthermore, large particles (i.e., particles with a core diameter greater than 4 nm) appear to be particularly well-suited for absorbing light with wavelengths up to 450 nm. Therefore, such particles are preferred for UV-protective coatings. For example, particles with large diameters can be used in the packaging of polymerizable liquids that polymerize under UV or violet-visible light.

Claims

1. A core-shell nanoparticle comprising: • ZnSe x S( 1-x ) material, where x is 0.80 to 0.98, and the core has: - for a core having a nanometer dimension in one dimension, a thickness of less than 10 nm, preferably less than 5 nm; - for a core having a nanometric size in two dimensions, the cross section is less than 100 nm 2 , preferably less than 50 nm 2 ; - for a core having a nanometer dimension in three dimensions, a diameter of less than 20 nm, preferably less than 15 nm, more preferably less than 10 nm; and • a shell of a ZnS material, the shell having a thickness of more than 0.3 nm and less than 5 nm, preferably more than 0.3 nm and less than 1.5 nm.

2. The core-shell nanoparticle according to claim 1, wherein sulfur is distributed in the core with a concentration gradient, preferably the concentration of sulfur in the center of the core is less than the concentration of sulfur in the periphery of the core.

3. The core-shell nanoparticle according to claim 1, wherein sulfur is distributed in an outer layer of the core.

4. The core-shell nanoparticle according to claim 3, wherein the core comprises a central portion, an outer layer, and a zinc sulfide shell, and wherein the central portion of the core has a diameter of 2 nm to 7 nm, the outer layer of the core has a thickness of 0.3 nm to 3 nm, and the zinc sulfide shell has a thickness of 0.3 nm to 3 nm.

5. The core-shell nanoparticle according to any one of claims 1 to 4, wherein the core has a diameter of less than 20 nm, and x is 0.80 to 0.

90.

6. The core-shell nanoparticle according to claim 5, wherein the shell has a thickness of more than 0.3 nm and less than 3 nm, preferably more than 0.3 nm and less than 1.5 nm.

7. The core-shell nanoparticle according to any one of claims 1 to 3, wherein the core has a thickness of less than 10 nm, and x is 0.80 to 0.

90.

8. The core-shell nanoparticle according to claim 7, wherein the shell has a thickness of more than 0.5 nm and less than 3 nm, preferably more than 0.6 nm and less than 1.5 nm.

9. A core-shell nanoparticle comprising: • ZnSe x S( 1-x ) material, where x is 0.60 to 0.98, and the core has: - for a core having a nanometer dimension in one dimension, a thickness of 3 nm to 10 nm; - for a core having a nanometric size in two dimensions, the cross section is 9 nm 2 up to 100 nm 2 ; - for a core having a nanometer dimension in three dimensions, a diameter of 3 nm to 20 nm; and • a shell of a ZnS material, the shell having a thickness of more than 0.3 nm and less than 5 nm, preferably more than 0.3 nm and less than 1.5 nm.

10. A composite particle comprising the core-shell nanoparticle according to any one of claims 1 to 9, the core-shell nanoparticle being embedded in an encapsulating material, preferably in a metal oxide encapsulating material.

11. The composite particle according to claim 10, wherein the loading of the core-shell nanoparticle in the composite particle is at least 1%, preferably at least 2.5%, more preferably at least 5%, the loading being the mass ratio of the mass of the core-shell nanoparticle contained in the composite particle to the mass of the composite particle.

12. The composite particle according to claim 10 or 11, wherein the average size of the composite particle is preferably 50 nm to 500 nm, more preferably 50 nm to 250 nm.

13. A light filtering material comprising a matrix material and at least one population of core-shell nanoparticles according to any one of claims 1 to 9 dispersed in the matrix material; or at least one population of composite particles according to any one of claims 9 to 10 dispersed in the matrix material.

14. The light filtering material according to claim 13, wherein the light filtering material has an absorbance of: • having a local maximum absorbance at a wavelength of 350 nm to 450 nm, the local maximum having an absorbance value A 最大 最大 at a wavelength of 350 nm to 450 nm, the local maximum having an absorbance value A 最大 最大 at a wavelength of 350 nm to 450 nm, the local maximum having an absorbance value A 最大 最大 at • has a value of 0.9 A 0.9 for the wavelength λ 最大 , λ 0.9 being greater than λ 最大 ; • has a value A for the wavelength λ 0.9 + 20 nm +20 ; and wherein 0.9A 最大 / A +20 greater than 25 or equal to 25, preferably greater than 50 or equal to 50, more preferably greater than 100 or equal to 100.

15. The light filtering material according to claim 14, wherein λ 最大 is from 370 nm to 420 nm, preferably from 375 nm to 400 nm, more preferably from 380 nm to 395 nm.

16. The light filtering material according to claim 13, wherein the light filtering material is obtained by curing a polymerizable composition comprising: • 0.1 to 10% by weight of zinc chalcogenide core-shell nanoparticles according to any one of claims 1 to 9 or composite particles according to any one of claims 10 to 12, • 0.1 to 10% by weight of an anti-UV organic compound, • optionally a stabilizer and / or an antioxidant, and • 15 to 40% by weight of a polymeric matrix material, the polymerizable composition having a dry extract of 15 to 70% by weight.

Images