Graphene-containing composite pigment for wood print and preparation method of graphene-containing composite pigment

Abstract

The invention provides a graphene-containing composite pigment for wood print and a preparation method thereof, and relates to the field of graphene, the composite pigment comprises 50-80 parts of a pigment color master batch, 0.5-5 parts of graphene oxide, 1-5 parts of a dispersant, 5-15 parts of a perovskite quantum dot complex, 1-5 parts of an antioxidant, 0.5-3 parts of a leveling agent and 20-35 parts of carrier oil. Wherein the perovskite quantum dot complex is of a core-shell structure, and a shell layer is formed by co-crystallization of organic halide and insulating nanoparticles; the preparation method comprises the following steps: performing in-situ reduction on graphene oxide and pigment color masterbatch in a solvent; reacting the quantum dot core with the shell precursor in an inert atmosphere to form a complex; all the components are subjected to ball milling and mixing. Through the synergistic effect of the graphene conductive network and the core-shell quantum dots, high conductivity is achieved, the retention rate of quantum dot fluorescence in 30 days is larger than 85%, and the problems that traditional pigments are poor in interactivity and insufficient in stability are solved.

Description

Technical Field

[0001] This invention relates to the field of graphene technology, specifically to a graphene-containing composite pigment for woodblock printing and its preparation method. Background Technology

[0002] Woodblock printing art relies on the color rendering properties and durability of specialized pigments. Traditional woodblock printing pigments are mainly made by mixing inorganic mineral pigments such as cinnabar and malachite or organic synthetic pigments such as phthalocyanine blue with natural carrier oils. Current woodblock printing pigment systems primarily rely on inorganic mineral or organic synthetic pigments, which, while meeting basic color rendering requirements, still have significant limitations. Specifically, traditional pigments have extremely high resistivity and lack stimuli responsiveness, making them unable to support the extended functions such as conductivity and temperature sensitivity required for interactive art creation; organic pigments are easily degraded and faded by environmental factors, while nanomaterials that can improve color rendering performance are difficult to disperse stably in oil-based systems due to their water and oxygen sensitivity; and nanomaterials exhibit poor dispersibility and weak adhesion on wood substrates. Therefore, there is an urgent need to develop a woodblock printing-specific composite material that combines high stability, multi-scenario interactive functionality, and environmental optimization. Summary of the Invention

[0003] The purpose of this invention is to provide a graphene-containing composite pigment for woodblock printing and its preparation method. Through the synergistic effect of graphene conductive network and core-shell quantum dots, high conductivity is achieved, and the fluorescence retention rate of quantum dots is >85% after 30 days, solving the problems of poor interaction and insufficient stability of traditional pigments.

[0004] To achieve the above objectives, the present invention proposes the following technical solution:

[0005] A graphene-containing composite pigment for woodblock printing, comprising the following components in parts by weight:

[0006] 50-80 parts of pigment masterbatch;

[0007] 0.5-5 parts of graphene oxide;

[0008] 1-5 parts dispersant;

[0009] The perovskite quantum dot complex consists of 5-15 parts, which has a core-shell structure. The core particles are perovskite quantum dots, and the shell is an ionic crystal layer formed by co-crystallization of organic halides and insulating nanoparticles.

[0010] Antioxidant 1-5 parts;

[0011] Leveling agent 0.5-3 parts;

[0012] 20-35 parts carrier oil.

[0013] As a preferred embodiment of the present invention, the dispersant is at least one of ammonium polyacrylate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0014] As a preferred embodiment of the present invention, the chemical formula of the perovskite quantum dots is AMX3, wherein:

[0015] A is Cs + 、Rb 2+ CH3NH3 + HC(NH2)2 + At least one of them;

[0016] M is Pb 2+ Sn 2+ 、Ge 2+ Cd 2+ Bi 3+ Mn 2+ Zn 2+ At least one of them;

[0017] X is Cl - ,Br - I - At least one of them.

[0018] As a preferred embodiment of the present invention, the insulating nanoparticles are selected from at least one of SiO2, Al2O3, and TiO2, and their particle size is 5-20 nm.

[0019] As a preferred embodiment of the present invention, the doping amount of the insulating nanoparticles in the shell is 10%-30% of the total mass of the shell.

[0020] As a preferred embodiment of the present invention, the organohalide is selected from at least one of methylamine hydrochloride, methylamine hydrobromide, methylamine hydroiodide, formamidin hydrochloride, formamidin hydrobromide, and formamidin hydroiodide.

[0021] This invention also provides a method for preparing a graphene-containing composite pigment for woodblock printing, comprising the following steps:

[0022] (1) Graphene oxide, pigment masterbatch and dispersant are mixed in a polar solvent, and then a non-polar solvent and metal reducing agent are added to react. The reaction is carried out at 20-40℃ for 5-30 min to obtain graphene mixed pigment. The volume ratio of polar solvent to non-polar solvent is 1:10-20.

[0023] (2) The perovskite quantum dot composite, the graphene mixed pigment, antioxidant, leveling agent and carrier oil are ball-milled and mixed for 1-3 hours to obtain the composite pigment.

[0024] As a preferred embodiment of the present invention, the method for preparing the perovskite quantum dot composite includes the following steps:

[0025] S1. Dissolve alkali metal halide and metal halide in a polar solvent at a 1:1 molar ratio, then inject into a non-polar solvent, and react at 30-40℃ to generate perovskite quantum dot nuclei.

[0026] S2. Organic halides and insulating nanoparticles are co-dispersed in a polar solvent to form a shell precursor solution;

[0027] S3. The perovskite quantum dot core particles obtained in S1 are added to the shell precursor solution and reacted at 45-60°C under an inert atmosphere for 1-3 hours to obtain the perovskite quantum dot composite.

[0028] As a preferred embodiment of the present invention, the polar solvent is at least one of N,N-dimethylformamide and N-methylpyrrolidone with a dielectric constant ≥20.

[0029] As a preferred embodiment of the present invention, the non-polar solution is at least one of toluene and hexane with a dielectric constant ≤10.

[0030] As can be seen from the above technical solutions, the present invention provides a graphene-containing composite pigment for woodblock printing and its preparation method. The present invention constructs a conductive network using graphene, imparting conductive properties to the pigment. Furthermore, it utilizes graphene sheets embedded in the micropores of wood to enhance interfacial bonding. By employing a perovskite quantum dot core-shell structure doped with insulating nanoparticles, the insulating nanoparticles are embedded in the ionic crystal layer, occupying lattice gaps, which reduces ionic conductivity, completely disrupts the continuous conductive pathway of the ionic crystal layer, and eliminates the Faraday cage effect.

[0031] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below can be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0033] The terms "first," "second," and similar words used in the specification and claims of this patent application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, unless the context clearly indicates otherwise, the singular forms of "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. Terms such as "comprising" or "including" mean that the element or object preceding "comprising" encompasses the features, integrals, steps, operations, elements, and / or components listed following "comprising" or "including," and do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components, and / or collections thereof.

[0034] This invention provides a graphene-containing composite pigment for woodblock printing, comprising the following components in parts by weight:

[0035] The pigment masterbatch consists of 50-80 parts, selected from one or more of the following: inorganic mineral pigments such as cinnabar, ultramarine, and iron oxide red; organic synthetic pigments such as phthalocyanine blue (BGS), permanent violet (RL), and quinacridone red; and natural plant pigments such as indigo and alizarin red. When selecting organic synthetic pigments, it is best to choose those with a temperature resistance ≥200℃ to avoid degradation during subsequent ball milling. Preferably, the selected pigment masterbatch should have a particle size ≤1μm or a D50 value to avoid excessively large particle sizes affecting the dispersibility of graphene.

[0036] 0.5-5 parts of graphene oxide are used to reduce graphene oxide, forming conductive pathways and significantly reducing resistivity, thus endowing the pigment with interactive functionality. Preferably, the thickness of the graphene oxide sheets is 1-10 nm, which can be measured by atomic force microscopy (AFM); the oxygen content is 20%-40%. The graphene obtained after the reduction of graphene oxide has a conductivity ≥10. 3 S / m can be measured using the four-probe method; the layer stacking thickness is ≤50nm. Graphene oxide is reduced in situ to form a layered conductive network, and graphene penetrates the pores of wood fibers to reduce interfacial contact resistance; its nanosheets are stacked alternately with pigment masterbatch particles to enhance mechanical anchoring.

[0037] The dispersant, in 1-5 parts, is at least one of ammonium polyacrylate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

[0038] The perovskite quantum dot complex, comprising 5-15 parts, imparts photocatalytic or thermally mutagenic properties to the pigment; it has a core-shell structure, wherein the core particles are perovskite quantum dots, and the shell is an ionic crystal layer formed by the co-crystallization of organic halides and insulating nanoparticles. The chemical formula of the perovskite quantum dots is AMX3, where A is Cs. + 、Rb 2+ CH3NH3 + HC(NH2)2+ At least one of them; M is Pb 2+ Sn 2+ 、Ge 2+ Cd 2+ Bi 3+ Mn 2+ Zn 2+ At least one of them; X is Cl - ,Br - I - At least one of the following. The insulating nanoparticles are selected from at least one of SiO2, Al2O3, and TiO2, and have a particle size of 5-20 nm; the doping amount of the insulating nanoparticles in the shell is 10%-30% of the total mass of the shell. The organohalide is selected from at least one of methylamine hydrochloride, methylamine hydrobromide, methylamine hydroiodide, formamidinium hydrochloride, formamidinium hydrobromide, and formamidinium hydroiodide.

[0039] Organic halides and insulating nanoparticles co-crystallize to form a dense shell. The insulating nanoparticles disrupt the conductive continuity of the ionic crystal, blocking electron transfer paths and preventing fluorescence quenching of the quantum dots. When the doping concentration of the insulating nanoparticles is 10%-30%, the oxygen permeability is extremely low, while maintaining defect passivation. Through the protection of this shell, the water and oxygen stability of the perovskite quantum dots is significantly improved, extending the fluorescence lifetime.

[0040] An antioxidant of 1-5 parts, selected from hindered phenols such as antioxidant 1010; phosphites such as antioxidant 168; BHT; or a composite antioxidant composed of hindered phenols and phosphites in a 1:1-2 ratio, synergistically inhibits the oxidation of the carrier oil. The composite antioxidant captures free radicals and decomposes hydroperoxides, synergistically inhibiting the oxidation chain reaction of the carrier oil.

[0041] 0.5-3 parts of leveling agent, selected from at least one of polyether-modified polydimethylsiloxane, polyether-modified siloxane, and fluorocarbon-modified acrylate. Adding the leveling agent increases the surface tension of the pigment, thereby improving the pigment's spreading efficiency in the wood capillaries and ensuring uniform spreading on the wood substrate.

[0042] The carrier oil is 20-35 parts, selected from at least one of refined flaxseed oil, tung oil, sunflower seed oil, and turpentine oil.

[0043] This invention also provides a method for preparing a graphene-containing composite pigment for woodblock printing, specifically including the following steps:

[0044] (1) Preparation of graphene-based mixed pigments:

[0045] Graphene oxide, pigment masterbatch, and dispersant are mixed in a polar solvent, followed by the addition of a non-polar solvent and a metal reducing agent. The reaction is carried out at 20-40℃ for 5-30 minutes to obtain a graphene mixed pigment. The volume ratio of the polar solvent to the non-polar solvent is 1:10-20. The polar solvent is at least one of N,N-dimethylformamide and N-methylpyrrolidone with a dielectric constant ≥20; the non-polar solvent is at least one of toluene and hexane with a dielectric constant ≤10. The metal reducing agent is selected from zinc powder, copper powder, etc.

[0046] (2) Preparation of perovskite quantum dot complexes:

[0047] S1. Dissolve alkali metal halide and metal halide in a polar solvent at a 1:1 molar ratio, then inject into a non-polar solvent, and react at 30-40℃ to generate perovskite quantum dot nuclei.

[0048] S2. Organic halides and insulating nanoparticles are co-dispersed in a polar solvent to form a shell precursor solution;

[0049] S3. The perovskite quantum dot core particles obtained in S1 are added to the shell precursor solution and reacted at 45-60°C under an inert atmosphere for 1-3 hours to obtain the perovskite quantum dot composite.

[0050] By forming an ionic crystal layer on the outside of the nucleus particles with organic halides, the perovskite quantum dots are coated to prevent water oxidation. Insulating particles such as SiO2, Al2O3, and TiO2 are embedded in the ionic crystal layer to disrupt the conductivity continuity of the ionic crystal layer, block the continuous conductive network, prevent the Faraday cage effect, and maintain the function of shell passivation defects.

[0051] (3) The perovskite quantum dot composite, the graphene mixed pigment, antioxidant, leveling agent and carrier oil are ball-milled and mixed for 1-3 hours to obtain the composite pigment.

[0052] This invention involves stepwise mixing of graphene and perovskite quantum dots to prevent the oxygen-containing groups in graphene oxide from quenching luminescence.

[0053] Example 1

[0054] Phthalocyanine Blue BGS pigment masterbatch, 65 parts, particle size 0.8μm;

[0055] 2.5 parts of graphene oxide, 32% oxygen content, 3nm thickness;

[0056] The dispersant is 3 parts polyacrylic acid;

[0057] Ten parts of perovskite quantum dot composite (CsPbBr3, methylamine hydrobromide) were used, with the insulating nanoparticles being SiO2, doped at 20%, and with a particle size of 15 nm.

[0058] The antioxidant is a compound antioxidant composed of antioxidants 1010 and 168 in a 1:1 ratio, 3 parts;

[0059] The leveling agent is 1.5 parts of polyether-modified siloxane leveling agent;

[0060] 25 parts refined flaxseed oil.

[0061] The specific preparation steps are as follows:

[0062] (1) Preparation of graphene-based mixed pigments

[0063] Graphene oxide, phthalocyanine blue (BGS), and ammonium polyacrylate were added to 30 mL of N,N-dimethylformamide (DMF) and dispersed by stirring at 60 °C for 20 min. After cooling, 300 mL of toluene and 0.4 g of zinc powder were added to the dispersion, and the mixture was reacted at 30 °C for 10 min. The zinc powder reduced the graphene oxide to conductive graphene, and the polarity gradient between DMF and toluene prevented the π-π aggregation of graphene, forming a stable dispersion.

[0064] (2) Preparation of perovskite quantum dot composites

[0065] 1 mmol CsBr and 1 mmol PbBr2 were dissolved in 5 mL LDM, injected into 50 mL toluene, and reacted at 35 °C for 10 min to obtain CsPbBr3 perovskite quantum dots.

[0066] 0.5 g of methylamine hydrobromide and 0.1 g of SiO2 were dispersed in 10 mL of DMF solution; then the CsPbBr3 perovskite quantum dots obtained above were added to the shell precursor solution and reacted at 50 °C under argon protection for 2 h to obtain the perovskite quantum dot composite.

[0067] (3) Add the graphene mixed pigment, perovskite quantum dot composite, antioxidant, leveling agent and linseed oil from step (1) into a ball milling jar, and ball mill zirconium dioxide beads (particle size 3 mm) at a ball-to-material ratio of 5:1 for 2 hours at 300 rpm to obtain the composite pigment.

[0068] Example 2

[0069] Example 2 differs from Example 1 in that: the amount of graphene oxide is increased to 4 parts, the oxygen content is 25%, and the sheet thickness is 2nm; the perovskite quantum dots are MAPbI3 and formamidinium hydroiodate, the insulating nanoparticles are Al2O3 with a doping amount of 25% and a particle size of 10nm; and the carrier oil is a 1:1 mixture of tung oil and turpentine oil, in 30 parts.

[0070] The preparation steps are adjusted as follows, while the rest are the same as in Example 1:

[0071] During the reduction of graphene oxide, the reaction was carried out at 40℃ for 10 minutes to increase the temperature and accelerate the reduction reaction.

[0072] Example 3

[0073] The difference from Example 1 is as follows:

[0074] The amount of graphene oxide was reduced to 1 part; the perovskite quantum dots were (Cs,FA)SnBr3 and formamidinium hydrobromide; and the insulating nanoparticles were TiO2 with a doping amount of 15% and a particle size of 8 nm.

[0075] The preparation steps are the same as in Example 1.

[0076] Comparative Example

[0077] The perovskite quantum dot composite was replaced with uncoated ordinary CsPbBr3 perovskite quantum dots, while all other steps remained the same as in Example 1. The preparation process involved directly mixing ordinary CsPbBr3 perovskite quantum dots with graphene-based pigments and other components.

[0078] The performance results of each embodiment and comparative example are shown in Table 1 below.

[0079] Table 1 Performance Test Results

[0080]

[0081] The fluorescence retention rate was tested under the following conditions: temperature 25℃ and humidity 60%.

[0082] Results analysis showed that, regarding conductivity, Example 2 exhibited the lowest resistivity due to its high graphene content and thin layers, forming a dense conductive network. Example 3, due to its high Sn content... 2+ Poor intrinsic conductivity and low graphene content result in a significant increase in resistivity.

[0083] The fluorescence retention rates of Examples 1-3 are far superior to those of the comparative examples, demonstrating that the particle crystal layer can block water and oxygen permeation, while the insulating nanoparticles disrupt the continuity of the ionic crystal, thus avoiding the Faraday cage effect.

[0084] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A graphene-containing composite pigment for woodblock printing, characterized in that, It contains the following components by weight: 50-80 parts of pigment masterbatch; 0.5-5 parts of graphene oxide; 1-5 parts dispersant; The perovskite quantum dot complex consists of 5-15 parts, which has a core-shell structure. The core particles are perovskite quantum dots, and the shell is an ionic crystal layer formed by co-crystallization of organic halides and insulating nanoparticles. Antioxidant 1-5 parts; Leveling agent 0.5-3 parts; 20-35 parts carrier oil.

2. The graphene-containing composite pigment for woodblock printing according to claim 1, characterized in that, The dispersant is at least one of ammonium polyacrylate, sodium dodecyl sulfate, and sodium dodecylbenzene sulfonate.

3. The graphene-containing composite pigment for woodblock printing according to claim 1, characterized in that, The chemical formula of the perovskite quantum dots is AMX3, wherein: A is Cs + 、Rb 2+ CH3NH3 + HC(NH2)2 + At least one of them; M is Pb 2+ Sn 2+ 、Ge 2+ Cd 2+ Bi 3+ Mn 2+ Zn 2+ At least one of them; X is Cl - ,Br - I - At least one of them.

4. The graphene-containing composite pigment for woodblock printing according to claim 1, characterized in that, The insulating nanoparticles are selected from at least one of SiO2, Al2O3, and TiO2, and their particle size is 5-20 nm.

5. The graphene-containing composite pigment for woodblock printing according to claim 1, characterized in that, The doping amount of the insulating nanoparticles in the shell is 10%-30% of the total mass of the shell.

6. The graphene-containing composite pigment for woodblock printing according to claim 1, characterized in that, The organohalide is selected from at least one of methylamine hydrochloride, methylamine hydrobromide, methylamine hydroiodide, formamidin hydrochloride, formamidin hydrobromide, and formamidin hydroiodide.

7. A method for preparing a graphene-containing composite pigment for woodblock printing as described in any one of claims 1-6, characterized in that, Includes the following steps: (1) Graphene oxide, pigment masterbatch and dispersant are mixed in a polar solvent, and then a non-polar solvent and metal reducing agent are added to react. The reaction is carried out at 20-40℃ for 5-30 min to obtain graphene mixed pigment. The volume ratio of polar solvent to non-polar solvent is 1:10-20. (2) The perovskite quantum dot composite, the graphene mixed pigment, antioxidant, leveling agent and carrier oil are ball-milled and mixed for 1-3 hours to obtain the composite pigment.

8. The method for preparing graphene-containing composite pigments for woodblock printing according to claim 7, characterized in that, The preparation method of the perovskite quantum dot complex includes the following steps: S1. Dissolve alkali metal halide and metal halide in a polar solvent at a 1:1 molar ratio, then inject into a non-polar solvent, and react at 30-40℃ to generate perovskite quantum dot nuclei. S2. Organic halides and insulating nanoparticles are co-dispersed in a polar solvent to form a shell precursor solution; S3. The perovskite quantum dot core particles obtained in S1 are added to the shell precursor solution and reacted at 45-60°C under an inert atmosphere for 1-3 hours to obtain the perovskite quantum dot composite.

9. The graphene-containing composite pigment for woodblock printing according to claim 7, characterized in that, The polar solvent is at least one of N,N-dimethylformamide and N-methylpyrrolidone with a dielectric constant ≥20.

10. The graphene-containing composite pigment for woodblock printing according to claim 7, characterized in that, The nonpolar solution is at least one of toluene or hexane with a dielectric constant ≤10.

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