Graphene quantum dot composite modified epoxy vegetable oil acrylate paint and preparation method

Abstract

The application discloses a graphene quantum dot composite modified epoxy vegetable oil acrylate coating and a preparation method thereof, and belongs to the technical field of environment-friendly photocuring coating. The epoxy vegetable oil acrylate is used as a base resin, and a hydroxylated graphene quantum dot modified by a surface grafting coupling agent, an active diluent, a photoinitiator and an additive are added to prepare the coating. The graphene quantum dot is modified in the application, so that the graphene quantum dot is uniformly dispersed in the resin matrix and forms a covalent bond with the resin matrix, the crosslinking density, the mechanical property, the corrosion resistance and the weather resistance of the coating are significantly improved, the problems of low hardness and poor corrosion resistance of the traditional epoxy vegetable oil acrylate coating are solved, and the coating has the advantages of green environmental protection, fast UV curing, strong adhesion and low shrinkage.

Description

Technical Field

[0001] This invention relates to the field of coating technology, and in particular to a graphene quantum dot composite modified epoxy vegetable oil acrylate coating and its preparation method. Background Technology

[0002] With increasingly stringent environmental policies and the advancement of the dual-carbon strategy, epoxy vegetable oil acrylates, made from renewable vegetable oils, have become an important green matrix resin for UV-cured coatings. This type of resin combines the high adhesion of epoxy groups, the rapid curing characteristics of acrylates, and the biodegradability of vegetable oils, significantly reducing VOC emissions and showing broad application prospects in wood products, packaging, and metal protection. However, pure epoxy vegetable oil acrylate cured films suffer from defects such as insufficient crosslinking density, poor weather resistance, susceptibility to yellowing, and low mechanical strength and corrosion barrier properties. Under harsh environments such as high humidity, strong corrosion, and prolonged sunlight exposure, they are prone to cracking, chalking, and decreased adhesion, making it difficult to meet the long-term protective requirements of high-end industrial coatings.

[0003] Graphene quantum dots (GQDs), as zero-dimensional carbon nanomaterials, possess characteristics such as large specific surface area, abundant functional groups, excellent dispersibility, and significant quantum size effect. They can form uniform nanocomposite networks in resin matrices, significantly improving the mechanical properties, density, aging resistance, and corrosion resistance of coatings. However, current technologies that directly blend graphene quantum dots with epoxy vegetable oil acrylates are prone to problems such as agglomeration, weak interfacial bonding, and limited performance improvement. There is a lack of composite modification and preparation processes adapted to this bio-based resin, making it difficult to achieve a synergistic effect of green environmental protection and high performance.

[0004] To address the aforementioned bottlenecks, it is necessary to develop a graphene quantum dot composite modified epoxy vegetable oil acrylate coating. Through interface regulation and the synergistic effect of nanocomposites, while retaining the green characteristics of bio-based coatings, the coating's curing efficiency, mechanical strength, weather resistance, and corrosion barrier properties can be significantly improved, meeting the urgent needs of high-end equipment, outdoor facilities, and electronic appliances for environmentally friendly high-performance coatings. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes a graphene quantum dot composite modified epoxy vegetable oil acrylate coating and its preparation method.

[0006] This invention provides a graphene quantum dot composite modified epoxy vegetable oil acrylate coating, comprising the following components, in parts by weight:

[0007] 50-80 parts of epoxy vegetable oil acrylate resin, 10-30 parts of reactive diluent 0.05-2 parts of graphene quantum dots 1-5 parts of photoinitiator Additives: 0.5-3 parts; The graphene quantum dots are hydroxylated graphene quantum dots, whose surface hydroxyl groups can provide active reaction sites, facilitating covalent grafting with coupling agents and improving dispersion stability in resin systems.

[0008] Furthermore, the epoxy vegetable oil acrylate is one or more of epoxy soybean oil acrylate, epoxy castor oil acrylate, and epoxy linseed oil acrylate. It uses natural vegetable oil as raw material, is green and environmentally friendly, has good flexibility, low cost and good biodegradability, and is the core film-forming matrix of the coating.

[0009] Furthermore, the hydroxylated graphene quantum dots have a particle size of 2-10 nm and a surface hydroxyl content of 2.0-5.0 mmol / g.

[0010] Furthermore, the reactive diluent is at least one selected from trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, ethoxyethoxyethyl acrylate, acrylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, triethylene glycol diacrylate, and tripropylene glycol diacrylate.

[0011] Furthermore, the photoinitiator is at least one of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, and isopropylthioxanthraphenone; the auxiliary agent includes one or more of dispersants, leveling agents, and defoamers.

[0012] Furthermore, the method for preparing the coating includes the following steps: S1: Disperse hydroxylated graphene quantum dots in an organic solvent, add a coupling agent, reflux at 60-90℃ for 2-6 hours for grafting, remove the organic solvent, and obtain grafted modified graphene quantum dots; S2: Mix epoxy vegetable oil acrylate resin and reactive diluent, heat to 40-60℃, add the grafted modified graphene quantum dots obtained in S1, disperse at high speed to obtain covalently bonded composite resin. S3: Add photoinitiator and additives to the composite resin, stir and filter to obtain graphene quantum dot composite modified epoxy vegetable oil acrylate coating.

[0013] Furthermore, the organic solvent mentioned in step S1 is any one of ethanol, isopropanol, and ethyl acetate.

[0014] Furthermore, the coupling agent in step S1 includes at least one of silane coupling agents, titanate coupling agents, and aluminate coupling agents; preferably, a silane coupling agent. The silane coupling agent can react simultaneously with the hydroxyl groups on the quantum dot surface and the acrylate resin, thereby maximizing the overall performance of the coating.

[0015] This invention provides an application of the graphene quantum dot composite modified epoxy vegetable oil acrylate coating in the protection, decoration and corrosion prevention of substrate surfaces.

[0016] Furthermore, the substrate includes any one or more of the following: metal substrate, wood substrate, plastic substrate, glass substrate, or composite material substrate.

[0017] In summary, compared with the prior art, the present invention achieves the following technical effects: (1) The present invention uses graphene quantum dots to modify epoxy vegetable oil acrylate. By performing surface grafting modification on graphene quantum dots, its dispersibility in the resin matrix is ​​significantly improved, effectively avoiding the agglomeration of nanofillers and making the internal structure of the coating more uniform and dense.

[0018] (2) By combining the modified graphene quantum dots with the resin matrix, the present invention significantly improves the crosslinking density, mechanical strength, surface hardness and wear resistance of the coating, and solves the problems of insufficient mechanical properties and easy scratching of the plant oil acrylate curing film in the prior art.

[0019] (3) The graphene quantum dots introduced in this invention can effectively improve the barrier properties and corrosion resistance of the coating, delay the penetration of moisture, ions and oxygen, and significantly extend the service life of the coating in corrosive environments and outdoor conditions.

[0020] (4) The coating provided by the present invention has excellent comprehensive performance, controllable preparation process and strong adaptability. It can be widely used as a protective and decorative coating for a variety of substrates such as metal, wood, plastic, glass and composite materials, and has high industrial application scenarios and market prospects. Detailed Implementation

[0021] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0022] Unless otherwise specified, the raw materials involved in the following specific embodiments of the present invention are all conventional materials in the art, and can be purchased from commercially available products. Some raw material information is as follows: Epoxy soybean oil acrylate resin: ZC8702, Kaiping Zicai Chemical Co., Ltd.; Trimethylolpropane triacrylate (TMPTA), Guangdong Yingtai New Materials Co., Ltd. Hydroxylated graphene quantum dots: XF091, Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; Silane coupling agent KH570: KH-570, Sinopharm Chemical Reagent Co., Ltd.; Isopropyltrioleoyl oxytitanate: NDZ-105, Nanjing Shuguang Chemical Group; Photoinitiator 1173: TRONLY TR 1173, Changzhou Qiangli New Materials; Polyether-modified polysiloxane leveling agent: BYK-333, BYK Chemicals; Organosilicon defoamer: BYK-017, BYK Chemical.

[0023] Performance testing methods: Pencil hardness: GB / T 6739-2006; Adhesion (cross-cut test): GB / T 9286-1996; Salt spray resistance: GB / T 1771-2007; Curing shrinkage rate: GB / T 1033.1-2022 (density method).

[0024] Example 1 A graphene quantum dot composite modified epoxy vegetable oil acrylate coating, the raw materials of which include: The composition includes 65 parts of epoxidized soybean oil acrylate resin, 22 parts of trimethylolpropane triacrylate, 0.3 parts of hydroxylated graphene quantum dots (hydroxyl content 3.2 mmol / g), 0.045 parts of silane coupling agent KH570, 3 parts of photoinitiator 1173, 0.4 parts of polyether modified polysiloxane leveling agent, and 0.3 parts of organosilicon defoamer.

[0025] Its preparation method includes the following steps: S1: Hydroxylated graphene quantum dots were dispersed in isopropanol to prepare a 2 mg / mL dispersion. Silane coupling agent KH570 was added, and the mixture was heated to 75 °C and refluxed with stirring for 4 h to complete surface covalent grafting. The organic solvent was removed by vacuum distillation to obtain grafted modified graphene quantum dots. S2: Mix epoxidized soybean oil acrylate and trimethylolpropane triacrylate, stir and mix well, then heat to 50°C, add the above modified quantum dots, and disperse at high speed of 5000r / min for 1h to ensure uniform dispersion of nanofillers without agglomeration, forming a covalently bonded composite resin. S3: Cool to room temperature, add photoinitiator, leveling agent and defoamer in sequence, stir at low speed for 30 minutes until completely mixed, filter through a 200-mesh filter to obtain the finished coating.

[0026] Example 2 The difference between this embodiment and Example 1 is that 0.1 parts of hydroxylated graphene quantum dots are used, while the process steps, reaction temperature, and dispersion speed are the same as in Example 1. Only the quantum dots are adjusted to obtain a low-addition modified coating.

[0027] Example 3 The difference between this embodiment and Example 1 is that 1.2 parts of hydroxylated graphene quantum dots were used, and the process steps, reaction temperature, and dispersion speed were the same as in Example 1. Only the quantum dots were adjusted to obtain a high-addition modified coating.

[0028] Example 4 The difference between this embodiment and Example 1 is that the epoxy vegetable oil acrylate resin is 78 parts, trimethylolpropane triacrylate is 12 parts, and photoinitiator 1173 is 3.5 parts. The process steps, reaction temperature, and dispersion speed are the same as in Example 1, and the modified coating is obtained.

[0029] Example 5 The difference between this embodiment and Example 1 is that the epoxy vegetable oil acrylate resin is 52 parts, trimethylolpropane triacrylate is 28 parts, and photoinitiator 1173 is 2.5 parts. The process steps, reaction temperature, and dispersion speed are the same as in Example 1, and the modified coating is obtained.

[0030] Example 6 The difference between this embodiment and Example 1 is that the coupling agent is isopropyltrioleoyloxytitanate (titanium ester coupling agent), and the process steps, reaction temperature, and dispersion speed are the same as in Example 1, thus obtaining the modified coating.

[0031] Comparative Example 1 A graphene quantum dot composite epoxy vegetable oil acrylate coating, the raw materials of which include: The composition ratio is exactly the same as in Example 1, except that the hydroxylated graphene quantum dots are not subjected to coupling agent grafting modification.

[0032] Its preparation method includes the following steps: S1: Unmodified hydroxylated graphene quantum dots, epoxidized soybean oil acrylate resin, and trimethylolpropane triacrylate are mixed, stirred and mixed evenly, and then heated to 50°C. The mixture is dispersed at a high speed of 5000 r / min for 1 h without covalent bonding process to obtain a physically blended composite resin. S2: Cool to room temperature, add photoinitiator, leveling agent and defoamer in sequence, stir at low speed for 30 minutes until completely mixed, filter through a 200-mesh filter to obtain the finished coating.

[0033] Comparative Example 2 An epoxy vegetable oil acrylate coating, the raw materials of which include: The difference between this comparative example and Example 1 is that no graphene quantum dots are added, and its preparation method includes the following steps: S1: Epoxy soybean oil acrylate resin and trimethylolpropane triacrylate are mixed, stirred and mixed evenly, and then heated to 50℃. The mixture is dispersed at a high speed of 5000r / min for 1h to achieve only physical dispersion of nanofillers without covalent bonding process, thus obtaining a physically blended composite resin. S2: Cool to room temperature, add photoinitiator, leveling agent and defoamer in sequence, stir at low speed for 30 minutes until completely mixed, filter through a 200-mesh filter to obtain the finished coating.

[0034] The coatings prepared in the examples and comparative examples were uniformly coated on a standard tinplate test plate and cured with 365nm ultraviolet light at an intensity of 400 mW / cm² for 30 s to obtain the coating to be tested.

[0035] After being placed at a temperature of 25±2℃ and a relative humidity of 50±5% for 24 h, the pencil hardness, adhesion, salt spray resistance and curing shrinkage of the coating were tested according to national standards. Each experiment was repeated 3 times and the average value was taken as the test result. The test results are shown in Table 1.

[0036] Table 1. Test results of acrylic coatings obtained from the examples and comparative examples.

[0037] The test results show that Example 1, which uses silane coupling agent KH570 to graft and modify hydroxylated graphene quantum dots with a quantum dot addition amount of 0.3 parts, exhibits the best performance in four indicators: pencil hardness, adhesion, salt spray resistance, and curing shrinkage rate, reaching 3H, 0 grade, 520 hours, and 2.1%, respectively, making it the preferred solution of this invention. Other examples, by adjusting the quantum dot addition amount, the resin-to-reactive diluent ratio, or changing the type of coupling agent, further verified that quantum dots have an optimal addition range, high resin content can optimize coating film formation, and the interfacial bonding effect of titanate coupling agents is inferior to that of silane coupling agent KH570. Although the performance of each component fluctuated slightly, it was generally superior to that of the comparative example. However, the performance of the comparative example 1, which was directly blended without quantum dot grafting, and the comparative example 2, which was pure resin without added quantum dots, was significantly reduced due to the failure of quantum dot aggregation or the lack of functional enhancement components. Their salt spray resistance time was only 180 hours and 120 hours, respectively, and the curing shrinkage rate was as high as 4.2% and 3.5%, respectively. This directly reflects the inherent defects of the traditional system and conversely confirms that the present invention effectively solves the technical problems of easy aggregation of nanofillers in resin and poor interfacial bonding through coupling agent grafting modification, which greatly improves the overall performance of the coating and has outstanding substantive features and significant technological progress.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A graphene quantum dot composite modified epoxy vegetable oil acrylate coating, characterized in that, Includes the following components, by weight: 50-80 parts of epoxy vegetable oil acrylate resin, 10-30 parts of reactive diluent 0.05-2 parts of graphene quantum dots 1-5 parts of photoinitiator Additives: 0.5-3 parts; The graphene quantum dots are hydroxylated graphene quantum dots.

2. The coating according to claim 1, characterized in that, The epoxy vegetable oil acrylate is one or more of the following: epoxy soybean oil acrylate, epoxy castor oil acrylate, and epoxy linseed oil acrylate.

3. The coating according to claim 1, characterized in that, The hydroxylated graphene quantum dots have a particle size of 2-10 nm and a surface hydroxyl content of 2.0-5.0 mmol / g.

4. The coating according to claim 1, characterized in that, The reactive diluent is at least one selected from trimethylolpropane triacrylate, 1,6-hexanediol diacrylate, ethoxyethoxyethyl acrylate, acrylmorpholine, N-vinylpyrrolidone, N-vinylcaprolactam, triethylene glycol diacrylate, and tripropylene glycol diacrylate.

5. The coating according to claim 1, characterized in that, The photoinitiator is at least one of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexylphenyl ketone, and isopropylthioxanthraphenone; the additives include one or more of dispersants, leveling agents, and defoamers.

6. The coating according to claim 1, characterized in that, The method for preparing the coating includes the following steps: S1: Disperse hydroxylated graphene quantum dots in an organic solvent, add a coupling agent, reflux at 60-90℃ for 2-6 hours for grafting, remove the organic solvent, and obtain grafted modified graphene quantum dots; S2: Mix epoxy vegetable oil acrylate resin and reactive diluent, heat to 40-60℃, add the grafted modified graphene quantum dots obtained in S1, disperse at high speed to obtain covalently bonded composite resin. S3: Add photoinitiator and additives to the composite resin, stir and filter to obtain graphene quantum dot composite modified epoxy vegetable oil acrylate coating.

7. The coating according to claim 6, characterized in that, The organic solvent mentioned in step S1 is any one of ethanol, isopropanol, and ethyl acetate.

8. The coating according to claim 6, characterized in that, The coupling agent in step S1 includes at least one of silane coupling agents, titanate coupling agents, and aluminate coupling agents; preferably, it is a silane coupling agent.

9. The application of the graphene quantum dot composite modified epoxy vegetable oil acrylate coating according to any one of claims 1-8 in the protection, decoration and corrosion prevention of substrate surfaces.

10. The application according to claim 9, characterized in that, The substrate includes any one or more of the following: metal substrate, wood substrate, plastic substrate, glass substrate, or composite material substrate.

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