Oily structural color pigment ink and use thereof

Abstract

An oily structural color pigment ink and the use thereof. The oily structural color pigment ink comprises the following components: at least one block polymer brush, at least one resin or at least one resin precursor, and at least one organic solvent. The oily structural color pigment ink is a layered structural color material obtained by self-assembly on the basis of a micro-phase separation principle of a block polymer brush. The provided oily structural color pigment ink can be compatible with most of the common pigment coloring methods, including but not limited to screen printing, spraying, inkjet printing, and gravure printing. The structural color of the oily structural color pigment ink is not limited to a visible light waveband, but instead also covers a ultraviolet spectrum, a visible spectrum and an infrared spectrum, and the wavelength range of the electromagnetic spectrum covered by the structural color is 200-2000 nm.

Description

An oil-based structural pigment ink and its application Technical Field

[0001] This invention belongs to the field of photonic crystal material preparation technology, specifically relating to an oil-based structural color pigment ink and its application. Background Technology

[0002] Pigments are substances used for coloring, capable of being uniformly dispersed in various media such as oils, resins, water, and organic solvents to provide color and hiding power. They are widely used in industries such as coatings, inks, plastics, rubber, ceramics, papermaking, textile printing and dyeing, and cosmetics. Historically, the pigment industry has played a vital role, providing a rich array of colors for artistic creation, industrial manufacturing, and daily life. However, over time, the development of this industry has gradually revealed some problems and limitations. First, the production process of traditional pigments is often accompanied by high energy consumption and high pollution. The production of many pigments requires the use of toxic or harmful chemicals, which may pose threats to the environment and human health during the production process. In addition, the extraction and processing of pigments may also lead to waste of resources and ecological damage. Second, the performance of traditional pigments has limitations in certain application areas. For example, they may perform poorly in terms of lightfastness, heat resistance, and chemical corrosion resistance, and the dyes or pigments themselves will slowly decompose and fade over time, limiting their use in high-end applications. Furthermore, the sustainability issues of traditional pigments are becoming increasingly prominent. With the increasing global emphasis on environmental protection and sustainable development, the production and use of traditional pigments are facing more and more restrictions. This requires the pigment industry to find new materials and technologies to reduce its environmental impact.

[0003] Structural color is an optical phenomenon generated by photonic crystals (PhCs). These artificial microstructured materials have significant applications in optics, particularly in color generation and manipulation. Photonic crystals can modulate light waves through their periodic structures, producing non-pigmented colors. These colors are generated by optical effects such as scattering, interference, and diffraction of light by the microstructures on the material's surface. Many examples of structural color exist in nature, exhibiting unique colors in living organisms. For instance, butterfly wings, peacock feathers, and beetle shells often derive their colors from the selective reflection of specific wavelengths by their unique periodic nanostructures. The wings of the blue morpho butterfly are a typical example of a one-dimensional photonic crystal, its structure producing a vivid blue structural color. Peacock feathers demonstrate the effect of a two-dimensional photonic crystal, its microscopic periodic stripe structure reflecting a vibrant structural color. Furthermore, opal, a gemstone, exhibits a unique play-of-color effect due to its internal accumulation of SiO2 microspheres, earning it the reputation of a gemstone palette. Even in everyday life, the cut surface of braised beef may exhibit a structural color effect, as the arrangement of its muscle fibers forms a two-dimensional photonic crystal structure that reflects a specific luster.

[0004] Currently, structural color materials are mainly prepared through the following methods: (1) Electron beam lithography: Two-dimensional photonic crystal films are prepared on substrates using electron beam direct writing and reactive ion beam etching. This method has high precision, but the processing time is long and the cost is high. (2) Colloidal particle self-assembly technology: Three-dimensional photonic crystals are formed by the self-assembly of colloidal microspheres in solution. This method has a long preparation time and is sensitive to external micro-disturbances, which may lead to structural defects. (3) Nanoimprint technology: Photonic crystal structures are quickly replicated by imprinting. It is suitable for large-area preparation, but there may be challenges in controlling the imprinting depth and uniformity. (4) Femtosecond laser direct writing: Photonic crystal structures are directly written on the material surface using femtosecond lasers. High-precision three-dimensional structures can be obtained, but the equipment cost is high and the production efficiency is relatively low. (5) Chemical vapor deposition: High-quality three-dimensional photonic crystals can be obtained by growing photonic crystals through chemical vapor deposition technology, but the preparation process is complex and has high requirements for equipment and environment. (6) Sol-gel method: Photonic crystals are prepared by the sol-gel method. The cost is low, but it is difficult to precisely control the aperture and shape, which may affect the performance of the photonic crystal. (7) Multi-beam coherent holography: Photonic crystals are prepared rapidly by multi-beam interference. It is applicable to a variety of lattice types, but it is limited by the laser wavelength and it is difficult to prepare a complete photonic bandgap in the visible light region.

[0005] Summary of the Invention

[0006] The purpose of this invention is to provide an oil-based structural color pigment ink and its applications. The oil-based structural color pigment ink provided by this invention is a layered structural color material obtained through self-assembly based on the microphase separation principle of block polymer brushes. The provided oil-based structural color pigment ink is compatible with most common pigment coloring methods, including but not limited to screen printing, spraying, inkjet printing, and gravure printing. The structural color of this oil-based structural color pigment ink is not limited to the visible light band, but covers the ultraviolet spectrum, visible spectrum, and infrared spectrum, with a wavelength range of 200nm-2000nm in the electromagnetic spectrum.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] One of the technical solutions of the present invention is to provide an oil-based structural color pigment ink, the components of which include: at least one block polymer brush (BBCP), at least one resin or at least one resin precursor, and at least one organic solvent.

[0009] Microphase separation can occur between the blocks in the block polymer brush, forming layered structural domains;

[0010] The resin or the resin precursor is compatible with at least one block of the block polymer brush and has a light transmittance of not less than 50%.

[0011] The block polymer brush used in this invention can undergo microphase separation through self-assembly, heating to a specific temperature, solvent evaporation-induced assembly, or printing processes such as scraping.

[0012] The block polymer brush (bottle-brush-like block polymer) of this invention refers to a polymer material with a special structure, characterized by the dense grafting of side-chain polymers onto the polymer backbone to form a brush-like morphology. The design and synthesis of this structure typically rely on precise polymerization techniques, such as living radical polymerization, atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer polymerization (RAFT), which also endow the block polymer brush with unique physicochemical properties. In particular, the densely grafted side chains make the self-assembly behavior of the block polymer brush significantly different from that of ordinary block polymers, making it easier to form ordered nanostructures, such as photonic crystals and nanowires, which have potential applications in optics and electronics. By changing the composition and degree of polymerization of the block polymer brush, its self-assembly behavior can be controlled, thereby preparing nanostructures with specific morphologies and chemical compositions.

[0013] Preferably, the block polymer brush comprises: polystyrene-b-polyethylene glycol (PPS-b-PPEO), polytert-butyl acrylate-b-polyethylene glycol (PPtBA-b-PPEO), polydimethylsiloxane-b-polyethylene glycol (PPDMS-b-PPEO), polymethyl methacrylate-b-polyethylene glycol (PPMMA-b-PPEO), polymethyl methacrylate-b-polyethylene glycol (PPMA-b-PPEO), polyacrylonitrile-b-polyethylene glycol (PPAN-b-PPEO), polylactic acid-b-polyethylene glycol (PPLA-b-PPEO), poly(ε-caprolactone-b-polyethylene glycol) (PPCL-b-PPEO), polyethylene-b-polyethylene glycol (PPE-b-PPEO), polypropylene-b-polyethylene glycol (PPP-b-PPEO), and polystyrene-b-polyacrylic acid (PPS-b-PPA). A) Polydimethylsiloxane-b-poly(methacrylic acid) (PPDMS-b-PPMAA), polydimethylsiloxane-b-polyvinylpyrrolidone (PPDMS-b-PPVP), polystyrene-b-poly(4-vinylpyridine) (PPS-b-PP4VP), polystyrene-b-poly(2-vinylpyridine) (PPS-b-PP2VP), polystyrene-b-polydimethylsiloxane-b-polyethylene glycol (P) (PS-b-PPDMS-b-PPEO), polystyrene-b-poly(tert-butyl acrylate)-b-polyethylene glycol (PPS-b-PPtBA-b-PPEO), poly(tert-butyl acrylate)-b-poly(dimethylsiloxane)-b-polyethylene glycol (PPtBA-b-PPDMS-b-PPEO), or polymethyl methacrylate-b-polystyrene-b-polyethylene glycol (PPMMA-b-PPS-b-PPEO).

[0014] The synthesis process of the block polymer brush described in this invention is based on patent US20210395463A1. Taking PPS-b-PPEO as an example: the first step is to obtain norbornene-terminated PS macromonomers via anionic polymerization; the second step is to obtain norbornene-terminated PEO macromonomers via esterification; and the third step is to perform ring-opening metathesis polymerization according to the method in patent US20210395463A1 to obtain the block polymer brush.

[0015] It should be noted that the synthesis methods of different norbornene-terminated macromonomers are determined according to actual production needs, including but not limited to anionic polymerization, cationic polymerization, macromolecular esterification, Click reaction or DA addition.

[0016] Preferably, the mass of the block polymer brush accounts for 15-80% of the total mass of the oil-based structural color pigment ink after removing the organic solvent.

[0017] In this invention, the microphase separation of the block polymer brush is the key to the self-assembly of the layered photonic crystal structure, which determines the size of the layered structure domain and the maximum reflection wavelength of the photonic crystal.

[0018] Preferably, the resin or the resin derived from the resin precursor includes: polystyrene, polyester, polyethylene ether, polyether, polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamide, polyurethane, polysiloxane, polyamide, polyethylene terephthalate, phenolic resin, urea resin, alkyd resin, epoxy resin, or silicone resin.

[0019] In this invention, the resin plays the role of swelling the layered structure of the photonic crystal to adjust the size of the structural domains. The selection of the resin should take into account factors such as the block polymer brush used, the subsequent processing performance requirements, and the subsequent performance requirements.

[0020] Preferably, the organic solvent includes: acetone, methanol, ethanol, dimethylformamide, toluene, dichloromethane, n-heptane, cyclohexane, ethyl acetate, butyl acetate, chloroform, diethyl ether, anisole, toluene, xylene, benzene, tetrachloromethane, pyridine, hexane, isopropanol, tetrahydrofuran, 1,4-dioxane, styrene, methyl methacrylate, or methyl acrylate.

[0021] In this invention, the organic solvent plays a role in adjusting the viscosity of the ink system and uniformly dispersing the components in the system. The primary requirement for selecting an organic solvent is its ability to dissolve other components in the system. In addition, the evaporation rate, polarity, viscosity, and other characteristics of the organic solvent also affect the final performance of the structural color ink.

[0022] Preferably, the composition of the oil-based structural color pigment ink further includes a regulating component.

[0023] More preferably, the regulating component includes one or more of the following: plasticizer, stabilizer, antioxidant, anti-aging agent, UV protectant, degrader, lubricant, heat stabilizer, foaming agent, antistatic agent, flame retardant, filler, coupling agent, processing modifier, nucleating agent, impact modifier, leveling agent, and defoamer.

[0024] The addition of regulating components in this invention is to improve the processing and performance of oil-based structural color pigment inks. Some of the regulating components are also used to adjust the color of the oil-based structural color pigment ink formulation.

[0025] The second technical solution of the present invention provides an application of the above-mentioned oil-based structural color pigment ink in screen printing, spraying, inkjet printing or gravure printing.

[0026] The method of using the oil-based structural color pigment ink provided by this invention is as follows:

[0027] The oil-based structural color pigment ink prepared by this invention can be used in conjunction with traditional pigment coloring methods. After the ink is printed onto the substrate, a photonic crystal structure covering the substrate surface can be obtained through solvent evaporation and post-treatment processes, thus producing structural color.

[0028] Solvent evaporation increases the viscosity of structural color inks, improving their adhesion to the substrate. Furthermore, the evaporation of some solvents can induce microphase separation in block polymer brushes, enhancing the order of the photonic crystal structure. Solvent evaporation can be achieved through environmental drying or active drying of printed materials (e.g., active drying using infrared / heat lamps or ultraviolet lamps). Active drying allows for rapid drying of the ink solution, enabling efficient multiple printing runs or other types of post-processing.

[0029] Post-printing treatments for oil-based structural pigment inks include, but are not limited to, annealing, curing the print, or printing protective varnishes, transparent coatings, or other surface materials on the print. The curing process typically depends on the type of resin used in the formulation and can employ methods including, but not limited to, UV curing, heat curing, air curing, or near-infrared curing to obtain a stable photonic crystal structure. The purpose of annealing is to promote microphase separation in the block polymer brush, resulting in a more ordered photonic crystal structure.

[0030] The color control method for oil-based structural pigment inks provided by this invention is as follows:

[0031] The color control methods for structural color inks can be broadly categorized into three types. First, during the preparation of structural color inks, a suitable block polymer brush (one or a mixture of multiple block polymer brushes), a suitable resin, and suitable adjusting components can be selected to directly formulate the desired color of the structural color ink. This process is similar to the preparation method for oil-based structural color pigment inks. Second, two different colored structural color inks can be premixed to obtain a new desired color with a reflection wavelength between the two. For example, a 1:1 mixture of red and blue structural color inks yields a green ink with a reflection wavelength between the two. Third, the desired color can be obtained through additive / subtractive color mixing principles. For instance, multiple printing operations using various structural color inks on the same substrate can create multilayer photonic crystal structures with varying domain sizes, which can then be combined to obtain the desired color. For example, using red, blue, and green structural color inks, colors covering the RGB color gamut can be printed.

[0032] The beneficial technical effects of the present invention are as follows:

[0033] The structural color coating obtained by the oil-based structural color pigment ink provided by the present invention can reflect ultraviolet-visible-infrared spectra covering the wavelength range of 200nm-2000nm.

[0034] The photonic crystals in the oil-based structural color pigment ink provided by this invention can be combined with traditional pigment coloring processes to obtain structural color coatings through printing.

[0035] The structural color of the oil-based structural color pigment ink provided by this invention can provide color effects that cannot be produced by current pigments and dyes, and theoretically can achieve arbitrary spectral design.

[0036] The oil-based structural color pigment ink provided by this invention can provide enhancement effects through pigments and dyes, and combine the formed structural color coating with pigments and dyes to achieve a wider range of colors, and generate new color gamuts through the mixing of subtractive and additive color mixing theories. Attached Figure Description

[0037] Figure 1 shows the LAB color model.

[0038] Figure 2 shows the reflection characteristics curves of the oil-based structural color pigment inks of formulations 1-5 in Example 1 after printing and heat treatment.

[0039] Figure 3 shows the reflection characteristics curves of the oil-based structural color pigment inks of formulations 6-10 in Example 2 after printing and light treatment.

[0040] Figure 4 shows the reflection characteristics curves of the oil-based structural color pigment inks of formulations 11-15 in Example 3 after printing and natural drying. Detailed Implementation

[0041] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.

[0042] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0043] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.

[0044] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0045] In this embodiment, color values ​​can be measured using the L*a*b* color space. The LAB color model (see Figure 1), also known as the CIELab color space, is a color space defined by the International Commission on Illumination (CIE) in 1976. It is a three-dimensional color space widely used for the calculation, comparison, and quantitative analysis of various colors. The LAB color model is characterized by its device independence and ability to uniformly reflect human visual perception. The LAB color model consists of three components: L* – the lightness component, representing the brightness of the color, ranging from 0 (pure black) to 100 (pure white); a* – the chromaticity component, representing the degree of color bias along the red-green axis, with negative values ​​biased towards green and positive values ​​towards red; and b* – the chromaticity component, representing the degree of color bias along the yellow-blue axis, with negative values ​​biased towards blue and positive values ​​towards yellow. The LAB color space has a very wide color gamut, encompassing not only all colors perceptible to the human eye but also some theoretical colors. This means that compared to the RGB and CMYK color spaces, LAB can describe colors more comprehensively. Color measurements should be performed using a spectrophotometer conforming to the standards of the International Commission on Illumination (CIE). The equipment should be calibrated regularly to ensure the accuracy of the measurement results.

[0046] Example 1

[0047] Prepare oil-based structural color pigment inks according to the formula in Table 1.

[0048] Table 1

[0049] In Table 1, BBCP is specifically PPS-b-PPEO (total molecular weight approximately 110W); the phenolic resin precursor is commercially available Inokai reagent (catalog number P832682-500g).

[0050] After printing the oil-based structural color pigment inks from formulations 1 to 5, heat treatment was performed (130℃, 4h). The color values ​​were measured, and the color gradation C was calculated using Origin. The measurement and calculation results are shown in Table 2.

[0051] Table 2

[0052] The precise color values ​​of formulas 1-5 after heat treatment are shown in Table 2, and the resulting photonic crystal is blue.

[0053] Figure 2 shows the reflection characteristics curves of the oil-based structural color pigment inks in formulations 1-5 after printing and heat treatment.

[0054] Example 2

[0055] Prepare oil-based structural color pigment inks according to the formulas in Table 3.

[0056] Table 3

[0057] In Table 3, BBCP is specifically PPS-b-PPEO (total molecular weight approximately 130W); the epoxy resin precursor is commercial epoxy acrylate agisin 1030; and the triaryl thioonium salt is the photoinitiator.

[0058] After printing the oil-based structural color pigment inks in formulations 6-10, they were subjected to light treatment (365nm ultraviolet light irradiation for 30 min), and the color values ​​were measured. The color saturation C was calculated using Origin. The measurement and calculation results are shown in Table 4.

[0059] Table 4

[0060] The precise color values ​​of formulas 6-10 after light treatment are shown in Table 4, and the resulting photonic crystal is blue.

[0061] Figure 3 shows the reflection characteristics curves of the oil-based structural color pigment inks in formulations 6-10 after printing and light treatment.

[0062] Example 3

[0063] Prepare oil-based structural color pigment inks according to the formulas in Table 5.

[0064] Table 5

[0065] In Table 3, BBCP is specifically PPCL-b-PPEO (total molecular weight approximately 90W); HT-400 is a leveling agent.

[0066] After printing the oil-based structural color pigment inks in formulations 11-15, they were allowed to dry naturally. The color values ​​were measured, and the color gradation C was calculated using Origin. The measurement and calculation results are shown in Table 6.

[0067] Table 6

[0068] The precise color values ​​of formulas 11-15 after printing and drying are shown in Table 6. The resulting photonic crystal is blue.

[0069] Figure 4 shows the reflection characteristics curves of the oil-based structural color pigment inks in formulations 11-15 after printing and natural drying.

[0070] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An oil-based structural color pigment ink, characterized in that, The components include: at least one block polymer brush, at least one resin or at least one resin precursor, and at least one organic solvent; Microphase separation can occur between the blocks in the block polymer brush, forming layered structural domains; The resin or the resin precursor is compatible with at least one block of the block polymer brush and has a light transmittance of not less than 50%.

2. The oil-based structural color pigment ink according to claim 1, characterized in that, The block polymer brush comprises: polystyrene-b-polyethylene glycol, poly(tert-butyl acrylate)-b-polyethylene glycol, poly(dimethylsiloxane)-b-polyethylene glycol, poly(methyl methacrylate)-b-polyethylene glycol, poly(methyl methacrylate)-b-polyethylene glycol, polyacrylonitrile-b-polyethylene glycol, polylactic acid-b-polyethylene glycol, poly(ε-caprolactone)-b-polyethylene glycol, polyethylene-b-polyethylene glycol, polystyrene-b-polyacrylic acid, and poly(ethylene methacrylate). Dimethylsiloxane-b-poly(methacrylic acid), poly(dimethylsiloxane-b-polyvinylpyrrolidone), polystyrene-b-poly(4-vinylpyridine), polystyrene-b-poly(2-vinylpyridine), polystyrene-b-poly(dimethylsiloxane-b-polyethylene glycol), polystyrene-b-poly(tert-butyl acrylate-b-polyethylene glycol), poly(tert-butyl acrylate-b-poly(dimethylsiloxane-b-polyethylene glycol) or poly(methyl methacrylate-b-polystyrene-b-polyethylene glycol).

3. The oil-based structural color pigment ink according to claim 1, characterized in that, The mass of the block polymer brush accounts for 15-80% of the total mass of the oil-based structural color pigment ink after removing the organic solvent.

4. The oil-based structural color pigment ink according to claim 1, characterized in that, The resin or the resin precursor formed from the resin includes: polystyrene, polyester, polyethylene ether, polyether, polyacrylate, polymethacrylate, polyacrylamide, polymethacrylamide, polyurethane, polysiloxane, polyamide, polyethylene terephthalate, phenolic resin, urea resin, alkyd resin, epoxy resin or silicone resin.

5. The oil-based structural color pigment ink according to claim 1, characterized in that, The organic solvents include: acetone, methanol, ethanol, dimethylformamide, toluene, dichloromethane, n-heptane, cyclohexane, ethyl acetate, butyl acetate, chloroform, diethyl ether, anisole, toluene, xylene, benzene, tetrachloromethane, pyridine, hexane, isopropanol, tetrahydrofuran, 1,4-dioxane, styrene, methyl methacrylate, or methyl acrylate.

6. The oil-based structural color pigment ink according to claim 1, characterized in that, The composition of the oil-based structural color pigment ink also includes adjusting components.

7. The oil-based structural color pigment ink according to claim 6, characterized in that, The regulating components include one or more of the following: plasticizers, stabilizers, antioxidants, anti-aging agents, UV protectants, degradants, lubricants, heat stabilizers, foaming agents, antistatic agents, flame retardants, fillers, coupling agents, processing modifiers, nucleating agents, impact modifiers, leveling agents, and defoamers.

8. The use of an oil-based structural color pigment ink as described in any one of claims 1 to 7 in screen printing, spraying, inkjet printing or gravure printing.

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