A porous graphene coating, its preparation method and applications

Abstract

This invention relates to the field of functional coatings technology, specifically disclosing a porous graphene coating, its preparation method, and its applications. The porous graphene coating is formed by applying a functional coating to the surface of a substrate and then curing it under laser irradiation. The functional coating includes a base coating and functional materials added to the base coating, including graphene, laser absorbers, and fillers. Addressing the core problem of existing graphene-containing coatings where graphene easily aggregates and is easily encapsulated by the coating matrix, resulting in low VOCs adsorption efficiency and difficulty in forming a stable porous structure, thus limiting adsorption capacity, this invention provides a porous graphene coating. By introducing laser absorbers into the coating formulation, the laser absorption capacity of the coating is enhanced. Combined with laser irradiation to achieve surface vaporization of the coating, the graphene is exposed and forms a porous structure, thereby significantly improving the coating's VOCs adsorption performance.

Description

Technical Field

[0001] This invention relates to the field of functional coatings technology, specifically to a porous graphene coating, its preparation method, and its applications. Background Technology

[0002] Volatile organic compounds (VOCs) generated after indoor decoration are one of the main pollutants affecting indoor air quality. They not only produce irritating odors, but some VOCs are also toxic, and long-term exposure can seriously harm human health. To address indoor VOC pollution, current technologies often employ the addition of adsorbent materials to coatings to prepare functional coatings, thereby achieving the adsorption and purification of VOCs.

[0003] Graphene, as a novel nanomaterial with an ultra-large specific surface area and excellent adsorption performance, has been widely explored for application in the field of VOCs adsorption materials. Currently, the technical solutions for applying graphene to coatings mostly involve directly mixing graphene powder into the coating system, forming a graphene-containing coating through coating application. However, this approach has the following drawbacks: ① On the one hand, graphene is prone to agglomeration in the coating, which prevents its specific surface area advantage from being fully utilized, thus limiting the VOCs adsorption efficiency; ② On the other hand, the graphene is encapsulated by the coating matrix and cannot directly contact VOCs in the air, further reducing the adsorption performance; ③ In addition, existing graphene-containing coatings are difficult to form a stable porous structure, have limited adsorption capacity, and are difficult to regenerate after adsorption saturation, resulting in a short service life.

[0004] Laser processing technology has advantages such as concentrated energy, good controllability, and high processing efficiency, and has been widely used in the field of material surface modification. However, how to combine laser processing technology with graphene coatings to solve the problems of low graphene utilization and poor adsorption performance of the coatings in existing graphene coatings has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a porous graphene coating that addresses the core problem of poor VOCs adsorption performance of existing graphene coatings.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a porous graphene coating, which is formed by applying a functional coating to the surface of a substrate and then curing it by laser irradiation; The functional coating includes a base coating and functional materials added to the base coating, wherein the functional materials include graphene, laser absorbers, and fillers.

[0007] Specifically, addressing the core pain point that existing graphene-containing coatings are prone to graphene agglomeration and encapsulation by the coating matrix, resulting in low VOCs adsorption efficiency and difficulty in forming a stable porous structure, thus limiting adsorption capacity, this invention provides a porous graphene coating. By introducing laser-absorbing substances into the coating formulation, the laser absorption capacity of the coating is enhanced. Combined with laser irradiation to achieve surface vaporization of the coating, the graphene is exposed and forms a porous structure, thereby significantly improving the coating's VOCs adsorption performance.

[0008] Specifically, this invention innovatively proposes an integrated approach of "functional coating application + laser irradiation curing," directly compounding functional materials such as graphene, laser absorbers, and fillers with a base coating. After coating, curing and the construction of a porous coating structure are achieved in one step through laser irradiation. This fundamentally solves the core pain points of complex processes, uneven dispersion, and difficulty in controlling the porous structure. The porous graphene coating constructed by this invention has multiple beneficial effects, such as excellent adsorption performance, mechanical stability, simple process, environmental protection and pollution-free, and large-scale production. It has extremely high practical value and broad industrial application prospects in the field of VOCs adsorption and purification, and at the same time provides a new technical path for the multifunctional and industrial development of porous graphene coatings.

[0009] Furthermore, a porous graphene coating: the base coating comprises a film-forming resin, a solvent, and additives; the solvent is selected from one or more of deionized water, ethanol, and propylene glycol methyl ether.

[0010] Furthermore, a porous graphene coating: the functional coating comprises the following components in parts by weight: 30-50 parts film-forming resin, 1-5 parts graphene, 0.5-3 parts laser-absorbing material, 10-20 parts solvent, 1-5 parts additives, and 20-40 parts filler.

[0011] Furthermore, a porous graphene coating is provided: the film-forming resin is selected from one or more of acrylic resin, polyurethane resin, and epoxy resin; the solvent is a mixture of deionized water and ethanol in a mass ratio of 1:(0.3-0.8).

[0012] Preferably, the film-forming resin is a water-based acrylic resin, which has good film-forming properties and is environmentally friendly. Preferably, the solvent is a mixture of deionized water and ethanol in a mass ratio of 1:(0.3-0.8), which can effectively adjust the viscosity of the coating and improve the dispersion uniformity of each component.

[0013] Furthermore, a porous graphene coating includes an additive comprising a dispersant, a defoamer, and a leveling agent; wherein the dispersant is a polycarboxylate dispersant, the defoamer is an organosilicon defoamer, and the leveling agent is an acrylate leveling agent.

[0014] Specifically, the dispersant is a polycarboxylate dispersant, added at a rate of 0.5 to 2.0 parts, which can effectively prevent the agglomeration of graphene and laser-absorbing substances; the defoamer is an organosilicon defoamer, added at a rate of 0.2 to 1.0 parts; and the leveling agent is an acrylate leveling agent, added at a rate of 0.3 to 2.0 parts.

[0015] Furthermore, a porous graphene coating: the graphene sheet has a diameter of 50-500 nm and a specific surface area of ​​≥300 m² / g, and is selected from one or more of graphene oxide, reduced graphene oxide, or modified graphene.

[0016] Furthermore, a porous graphene coating is provided: the laser-absorbing material has a particle size of 20-200 nm, and is selected from one or more of carbon black, nano-titanium dioxide, and nano-iron oxide. Preferably, carbon black is used as the laser-absorbing material, which has excellent absorption performance for near-infrared lasers, and is inexpensive and easily compatible with coating systems.

[0017] Furthermore, a porous graphene coating is provided: the filler has a particle size of 1–10 μm and is selected from one or more of talc, calcium carbonate, and diatomaceous earth. Specifically, the filler can improve the mechanical strength and workability of the coating.

[0018] This invention also provides a method for preparing a porous graphene coating, the method comprising the following steps: S1. Preparation of functional coatings: Weigh film-forming resin, solvent and additives, stir at 500-800 rpm for 10-20 minutes to obtain a base coating; add graphene and laser-absorbing material to the base coating, stir at 1200-1500 rpm for 30-60 minutes, add filler and continue stirring for 20-30 minutes, then grind until the coating particle size is ≤50μm and filter to obtain the functional coating; S2. Coating application: The functional coating is applied to the substrate surface with a coating thickness of 50-200 μm and dried at room temperature for 12-24 hours to form a dry film. S3. Laser Irradiation Treatment: The dry film is irradiated with a pulsed laser for 10–60 seconds. The laser wavelength is 1064 nm, the power is 50–200 W, the scanning speed is 100–500 mm / s, and the spot diameter is 0.1–0.5 mm. During the laser irradiation process, the surface of the dry film absorbs the laser heat and vaporizes, exposing the graphene inside to the coating surface. At the same time, the graphene forms a porous structure under the local high temperature, and finally a porous graphene coating is obtained.

[0019] Specifically, the coating method in step S2 can be brush coating, roller coating, or spray coating. The present invention also provides a use of a porous graphene coating in the adsorption and purification of VOCs.

[0020] The beneficial effects of this invention are: The porous graphene coating of this invention is formed by functional coatings. By introducing laser-absorbing substances into the functional coating system, the coating's ability to absorb laser light is significantly improved. This allows the coating surface to quickly absorb heat and vaporize during laser irradiation, thereby exposing the graphene encapsulated within the coating. This avoids the problem of graphene being unable to fully exert its adsorption function due to being encapsulated by the coating matrix, greatly improving the utilization rate of graphene and enhancing the coating's adsorption capacity. Simultaneously, the localized high temperature generated during laser irradiation promotes the formation of a stable porous structure in the graphene. This porous structure further increases the specific surface area of ​​the graphene, significantly improving the coating's adsorption capacity and efficiency for VOCs.

[0021] The porous graphene coating of this invention has a simple preparation process and the construction method is the same as that of conventional household paint. It does not require special construction equipment and is easy to promote industrially. Moreover, the laser irradiation treatment parameters are controllable and the operation is convenient. The porous structure and graphene exposure of the coating can be adjusted according to actual needs. The porous graphene coating prepared by this invention not only has excellent VOCs adsorption performance, but also has good mechanical strength and weather resistance. It can be used for indoor wall decoration and air purification for a long time, combining practicality and environmental protection.

[0022] This invention utilizes the synergistic effect of laser irradiation and laser absorbers to precisely induce the formation of a porous coating with uniform pore size and good connectivity. Simultaneously, the rational combination of nanoscale graphene and micron-scale fillers creates a micro-nano hierarchical porous structure, further increasing the coating's specific surface area and fully exposing the graphene adsorption sites, effectively enhancing the coating's VOCs adsorption capacity. Furthermore, the coating of this invention exhibits a tight bond with the substrate. Through the curing action of the film-forming resin, functional materials such as graphene and fillers are firmly fixed to the substrate surface, preventing the problem of graphene adsorption material easily detaching or leaking, extending the coating's service life, and ensuring long-term stable adsorption performance. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a scanning electron microscope image of the porous graphene coating prepared in Example 1; Figure 2This is a scanning electron microscope image of the porous graphene coating prepared in Example 2; Figure 3 This is a scanning electron microscope image of the graphene-coated sample prepared in Comparative Example 1. Detailed Implementation

[0025] The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention. Example

[0026] Example 1 provides a porous graphene coating, which is formed by applying a functional coating to the surface of a substrate and then curing it by laser irradiation; The functional coating includes a base coating and functional materials added to the base coating. The base coating includes a film-forming resin, a solvent, and additives. The solvent includes deionized water and ethanol. The additives include dispersants, defoamers, and leveling agents. The functional materials include graphene, laser absorbers, and fillers. The film-forming resin is an aqueous acrylic resin; the dispersant, defoamer, and leveling agent are respectively a polycarboxylate dispersant, an organosilicon defoamer, and an acrylate leveling agent; the graphene is reduced graphene oxide; the laser absorber is carbon black; and the filler is talc. Specifically, the functional coating comprises the following components in parts by weight: 35.0 parts of waterborne acrylic resin, 2.0 parts of reduced graphene oxide, 1.0 part of carbon black, 12.0 parts of deionized water, 5.0 parts of ethanol, 1.0 part of polycarboxylate dispersant, 0.5 parts of silicone defoamer, 0.8 parts of acrylate leveling agent, and 28.7 parts of talc.

[0027] Preparation method: The method for preparing the porous graphene coating in Example 1 above includes the following steps: S1. Preparation of functional coating: Weigh 35.0 parts by weight of waterborne acrylic resin, 12.0 parts by weight of deionized water, 5.0 parts by weight of ethanol, 1.0 part by weight of polycarboxylate dispersant, 0.5 parts by weight of silicone defoamer, and 0.8 parts by weight of acrylate leveling agent. Place them in a high-speed mixing tank and stir at 600 rpm for 15 minutes to obtain a base coating. Then add 2.0 parts by weight of reduced graphene oxide and 1.0 parts by weight of carbon black to the base coating, increase the speed to 1300 rpm and stir for 45 minutes. Then add 28.7 parts by weight of talc powder and continue stirring for 25 minutes. Then grind the coating with a sand mill until the particle size is 35 μm. Finally, filter to obtain the functional coating. S2. Coating application: The above-mentioned functional coating is applied to the interior wall surface by roller coating, with a coating thickness of 100μm, and dried at room temperature for 18 hours to form a dry film; S3. Laser Irradiation Treatment: The dry film is irradiated with a pulsed laser for 30 seconds. The laser wavelength is 1064nm, the laser power is 100W, the scanning speed is 200mm / s, and the spot diameter is 0.2mm. During the laser irradiation process, the surface of the dry film absorbs the laser heat and vaporizes, exposing the graphene inside to the coating surface. At the same time, the graphene forms a porous structure under the local high temperature, and finally a porous graphene coating is obtained.

[0028] Scanning electron microscope images of the porous graphene coating obtained in Example 1 above are shown below. Figure 1 As shown. Example

[0029] Example 2 provides a porous graphene coating, which is formed by applying a functional coating to the surface of a substrate and then curing it by laser irradiation; The functional coating comprises the following components in parts by weight: 35.0 parts of waterborne acrylic resin, 2.0 parts of graphene oxide, 1.0 part of carbon black, 12.0 parts of deionized water, 5.0 parts of ethanol, 1.0 part of polycarboxylate dispersant, 0.5 parts of silicone defoamer, 0.8 parts of acrylic ester leveling agent, and 28.7 parts of talc.

[0030] The difference between Example 2 and Example 1 is that in Example 2, the reduced graphene oxide in Example 1 is replaced with graphene oxide, while the other conditions are the same as in Example 1.

[0031] Scanning electron microscope images of the porous graphene coating obtained in Example 2 above are shown below. Figure 2 As shown. Example

[0032] Example 3 provides a porous graphene coating, which is formed by applying a functional coating to the surface of a substrate and then curing it by laser irradiation; The functional coating comprises the following components in parts by weight: 45.0 parts epoxy resin, 3.0 parts modified graphene, 2.0 parts nano titanium dioxide, 10.0 parts deionized water, 5.0 parts ethanol, 1.5 parts polycarboxylate dispersant, 0.8 parts silicone defoamer, 1.2 parts acrylate leveling agent, and 36.5 parts calcium carbonate.

[0033] The method for preparing the porous graphene coating in Example 3 above includes the following steps: S1. Preparation of functional coating: Weigh 45.0 parts by weight of epoxy resin, 10.0 parts by weight of deionized water, 5.0 parts by weight of ethanol, 1.5 parts by weight of polycarboxylate dispersant, 0.8 parts by weight of silicone defoamer, and 1.2 parts by weight of acrylate leveling agent. Place them in a high-speed mixing tank and stir at 500 rpm for 20 minutes to obtain a base coating. Then add 3.0 parts by weight of modified graphene and 2.0 parts by weight of nano titanium dioxide to the base coating. Increase the speed to 1200 rpm and stir for 60 minutes. Then add 36.5 parts by weight of calcium carbonate and continue stirring for 20 minutes. Then grind the coating with a sand mill until the particle size is 45 μm. Finally, filter to obtain the functional coating. S2. Coating application: The above-mentioned functional coating is applied to the interior wall surface by roller coating, with a coating thickness of 150μm, and dried at room temperature for 12 hours to form a dry film; S3. Laser Irradiation Treatment: The dry film is irradiated with a pulsed laser for 20 seconds. The laser wavelength is 1064nm, the laser power is 120W, the scanning speed is 150mm / s, and the spot diameter is 0.3mm. During the laser irradiation process, the surface of the dry film absorbs the laser heat and vaporizes, exposing the graphene inside to the coating surface. At the same time, the graphene forms a porous structure under the local high temperature, and finally a porous graphene coating is obtained. Example

[0034] Example 4 provides a porous graphene coating, which is formed by applying a functional coating to the surface of a substrate and then curing it by laser irradiation; The functional coating comprises the following components in parts by weight: 35.0 parts of waterborne acrylic resin, 3.0 parts of reduced graphene oxide, 1.0 part of carbon black, 12.0 parts of deionized water, 5.0 parts of ethanol, 1.0 part of polycarboxylate dispersant, 0.5 parts of silicone defoamer, 0.8 parts of acrylic ester leveling agent, and 27.7 parts of talc.

[0035] The method for preparing the porous graphene coating in Example 4 above includes the following steps: S1. Preparation of functional coating: Weigh 35.0 parts by weight of waterborne acrylic resin, 12.0 parts by weight of deionized water, 5.0 parts by weight of ethanol, 1.0 part by weight of polycarboxylate dispersant, 0.5 parts by weight of silicone defoamer, and 0.8 parts by weight of acrylate leveling agent. Place them in a high-speed mixing tank and stir at 600 rpm for 15 minutes to obtain a base coating. Then add 3.0 parts by weight of reduced graphene oxide and 1.0 part by weight of carbon black to the base coating, increase the speed to 1300 rpm and stir for 45 minutes. Then add 27.7 parts by weight of talc powder and continue stirring for 25 minutes. Then grind the coating with a sand mill until the particle size is 35 μm. Finally, filter to obtain the functional coating. S2. Coating application: The above-mentioned functional coating is applied to the interior wall surface by roller coating, with a coating thickness of 100μm, and dried at room temperature for 18 hours to form a dry film; S3. Laser Irradiation Treatment: The dry film is irradiated with a pulsed laser for 30 seconds. The laser wavelength is 1064nm, the laser power is 100W, the scanning speed is 200mm / s, and the spot diameter is 0.2mm. During the laser irradiation process, the surface of the dry film absorbs the laser heat and vaporizes, exposing the graphene inside to the coating surface. At the same time, the graphene forms a porous structure under the local high temperature, and finally a porous graphene coating is obtained.

[0036] The difference between Example 4 and Example 1 is that in Example 4, the amount of reduced graphene oxide added in Example 1 is increased from 2.0 parts to 3.0 parts, and the amount of talc is reduced by 1.0 part to ensure that the total number of parts is the same, while the other components and their amounts remain unchanged. Example

[0037] The components and contents of the functional coating in Example 5 are the same as those in Example 1. The only difference is that the laser power in the preparation method of Example 5 is increased from 100W to 150W. The other preparation parameters are the same as those in Example 1.

[0038] Comparative Example 1 A graphene-containing coating is provided, comprising the following components in parts by weight: 35.0 parts of waterborne acrylic resin, 2.0 parts of reduced graphene oxide, 12.0 parts of deionized water, 5.0 parts of ethanol, 1.0 part of polycarboxylate dispersant, 0.5 parts of silicone defoamer, 0.8 parts of acrylate leveling agent, and 29.7 parts of talc.

[0039] The above-mentioned graphene-containing coating is prepared into a coating by the following steps: S1. Preparation of graphene-containing coating: Weigh 35.0 parts by weight of waterborne acrylic resin, 12.0 parts by weight of deionized water, 5.0 parts by weight of ethanol, 1.0 part by weight of polycarboxylate dispersant, 0.5 parts by weight of silicone defoamer, and 0.8 parts by weight of acrylate leveling agent. Place them in a high-speed mixing tank and stir at 600 rpm for 15 minutes to obtain a base coating. Then add 2.0 parts by weight of reduced graphene oxide to the base coating, increase the speed to 1300 rpm and stir for 45 minutes. Then add 29.7 parts by weight of talc powder and continue stirring for 25 minutes. Then grind the coating with a sand mill until the particle size is 35 μm. Finally, filter to obtain a functional coating. S2. Coating application: The above-mentioned functional coating is applied to the surface of the interior wall by roller coating, with a coating thickness of 100μm. It is dried at room temperature for 18 hours to form a dry film. No laser irradiation treatment is performed to obtain a graphene-containing coating.

[0040] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 only removes the laser-absorbing substance carbon black from Example 1, and increases the amount of talc powder by 1.0 part to ensure that the total number of parts is the same, while the other components and their amounts remain unchanged.

[0041] The scanning electron microscope image of the coating obtained in Comparative Example 1 is as follows: Figure 3 As shown.

[0042] test: The VOCs adsorption performance of the coatings in Examples 1-5 and Comparative Example 1 were tested. The test conditions were: test chamber volume 1.0 m³, initial VOCs (formaldehyde, benzene, and toluene mixture) concentration 100 mg / m³, temperature 25°C, humidity 50%, and test time 24 hours. The test results are shown in Table 1 below. The test results of Example 1 and Comparative Example 1 show that the addition of laser-absorbing material significantly improves the VOCs removal rate and specific surface area of ​​the coating. This invention prepares a functional coating by combining graphene and laser-absorbing material in the coating system. After coating the coating on a wall and drying it into a film, it is cured by pulsed laser irradiation. The laser-absorbing material enhances the laser absorption capacity of the coating, causing the surface layer to rapidly absorb heat and vaporize, thereby exposing the internal graphene. Simultaneously, the localized high temperature promotes the formation of a porous structure in the graphene, increasing the coating's adsorption capacity. The preparation process of this coating is simple and convenient. Through the synergistic effect of graphene exposure and the porous structure, it significantly improves the adsorption capacity and efficiency for VOCs, combining decorative and air purification functions, and can be widely used in the field of indoor VOCs adsorption and purification.

[0043] The above-described preferred embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of the invention. Any obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A porous graphene coating, characterized in that, The coating is formed by applying functional coatings to the surface of a substrate and then curing them by laser irradiation. The functional coating includes a base coating and functional materials added to the base coating, wherein the functional materials include graphene, laser absorbers, and fillers.

2. The porous graphene coating according to claim 1, characterized in that, The base coating comprises a film-forming resin, a solvent, and additives; the solvent is selected from one or more of deionized water, ethanol, and propylene glycol methyl ether.

3. The porous graphene coating according to claim 2, characterized in that, The functional coating comprises the following components in parts by weight: 30-50 parts film-forming resin, 1-5 parts graphene, 0.5-3 parts laser-absorbing material, 10-20 parts solvent, 1-5 parts additives, and 20-40 parts filler.

4. The porous graphene coating according to claim 2, characterized in that, The film-forming resin is selected from one or more of acrylic resin, polyurethane resin, and epoxy resin; the solvent is a mixture of deionized water and ethanol in a mass ratio of 1:(0.3-0.8).

5. The porous graphene coating according to claim 3, characterized in that, The additives include dispersants, defoamers, and leveling agents; The dispersant is a polycarboxylate dispersant, the defoamer is an organosilicon defoamer, and the leveling agent is an acrylate leveling agent.

6. The porous graphene coating according to claim 1, characterized in that, The graphene has a sheet diameter of 50–500 nm and a specific surface area of ​​≥300 m² / g, and is selected from one or more of graphene oxide, reduced graphene oxide, or modified graphene.

7. The porous graphene coating according to claim 1, characterized in that, The particle size of the laser-absorbing material is 20-200 nm, and it is selected from one or more of carbon black, nano titanium dioxide, and nano iron oxide.

8. The porous graphene coating according to claim 1, characterized in that, The filler has a particle size of 1 to 10 μm and is selected from one or more of talc, calcium carbonate, and diatomaceous earth.

9. A method for preparing a porous graphene coating according to any one of claims 1 to 8, characterized in that, The method includes the following steps: S1. Preparation of functional coatings: Weigh film-forming resin, solvent and additives, stir at 500-800 rpm for 10-20 minutes to obtain a base coating; add graphene and laser-absorbing material to the base coating, stir at 1200-1500 rpm for 30-60 minutes, add filler and continue stirring for 20-30 minutes, then grind until the coating particle size is ≤50μm and filter to obtain the functional coating; S2. Coating application: The functional coating is applied to the substrate surface with a coating thickness of 50-200 μm and dried at room temperature for 12-24 hours to form a dry film. S3. Laser irradiation treatment: The dry film is irradiated with a pulsed laser for 10 to 60 seconds to obtain a porous graphene coating.

10. The use of a porous graphene coating according to any one of claims 1 to 8, characterized in that, Application of the porous graphene coating in VOCs adsorption and purification.

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