Fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating and preparation method thereof

Abstract

The invention relates to the technical field of epoxy resin coatings, and particularly discloses a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating and a preparation method thereof. The fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating comprises the following components in parts by weight: 100 parts of fluorine modified epoxy resin, 1-2.5 parts of fluorinated carbon nanotubes, 40-60 parts of a curing agent, 80-120 parts of a propylene glycol methyl ether acetate / dibasic acid ester mixed solvent, 0.3 part of a flatting agent and 0.2 part of a defoaming agent, the fluorine modified epoxy resin is prepared from a fluorine compound and epoxy resin through reaction; the fluorine compound is one of 1H, 1H-perfluorooctyl acrylate and 1H, 1H-perfluorooctyl methacrylate, and the fluorine compound is one of 1H, 1H-perfluorooctyl acrylate and 1H, 1H-perfluorooctyl methacrylate. A coating prepared from the coating has high hardness and high toughness.

Description

Technical Field

[0001] The present invention relates to the technical field of epoxy resin coatings, and in particular to a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating and a preparation method thereof. Background Art

[0002] Epoxy resins are widely used in high-performance protective coatings, composite materials, and electronic packaging due to their excellent bonding properties, chemical stability, electrical insulation, and good processing properties. However, while traditional epoxy resin-based materials exhibit high modulus and strength, their inherent molecular chain rigidity and highly cross-linked network structure also lead to inherent brittleness, manifesting as poor impact resistance and insufficient toughness. They are prone to cracking and failure when subjected to external forces or severe deformation. This toughness deficiency severely limits the reliability and service life of epoxy resins in demanding environments, such as aerospace, marine engineering, and high-end equipment protection.

[0003] To improve the toughness of epoxy resins, the industry has developed a variety of toughening and modification technologies. Common methods include physical blending of toughening agents (such as carboxyl-terminated nitrile rubber, thermoplastics, and nanofillers) or chemical modification by introducing flexible molecular segments. While these methods improve toughness to a certain extent, they often inevitably sacrifice the material's strength and modulus. Furthermore, compatibility issues between the toughening agent and the epoxy matrix can lead to phase separation, affecting the material's homogeneity and long-term stability.

[0004] On the other hand, introducing nanofillers (such as carbon nanotubes, graphene, nanosilica, etc.) into the epoxy resin matrix is ​​an effective way to improve its comprehensive properties (such as strength, modulus, electrical / thermal conductivity). However, nanofillers are very prone to serious agglomeration in the polymer matrix. The poor dispersion of nanofillers not only limits their full performance, resulting in reinforcement / toughening efficiency far below theoretical expectations, but also the agglomerates themselves may become stress concentration points, inducing material defects and compromising the ultimate mechanical properties and reliability. Although researchers have tried various dispersion methods (such as physical dispersion, surface modifier treatment, silane coupling agent modification, etc.), the special interfacial compatibility between nanofillers and epoxy resin matrix, especially how to achieve high stability and uniform dispersion while solving the intrinsic brittleness of the resin matrix, remains a huge technical challenge. Summary of the Invention

[0005] In view of the shortcomings of the existing methods, the present invention provides a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating, wherein the components of the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating include, by weight: 100 parts of fluorine-modified epoxy resin, 1-2.5 parts of fluorinated carbon nanotubes, 40-60 parts of curing agent, 80-120 parts of propylene glycol methyl ether acetate / dibasic acid ester mixed solvent, 0.3 parts of leveling agent, 0.2 parts of defoaming agent.

[0006] Furthermore, the fluorine-modified epoxy resin is prepared by reacting a fluorine compound and an epoxy resin.

[0007] Furthermore, the epoxy resin is epoxy resin 604.

[0008] Furthermore, the mass ratio of the epoxy resin to the fluorine compound is 100:3-5.

[0009] Furthermore, the fluorine compound is one of 1H,1H-perfluorooctyl acrylate and 1H,1H-perfluoro-n-decyl methacrylate.

[0010] Furthermore, the fluorine content of the fluorinated carbon nanotubes is 20-60 wt%.

[0011] Furthermore, the curing agent is Ancamide 350A.

[0012] Furthermore, the volume ratio of propylene glycol methyl ether acetate to dibasic acid ester in the propylene glycol methyl ether acetate / dibasic acid ester (DBE) mixed solvent is 3:1.

[0013] Furthermore, the defoaming agent is BYK-055.

[0014] Furthermore, the leveling agent is BYK-331.

[0015] The preparation method of the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating comprises the following steps: S1: stirring and mixing the fluorine-modified epoxy resin and propylene glycol methyl ether acetate / dibasic acid ester mixed solvent to obtain a resin slurry; S2: mixing fluorinated carbon nanotubes and a mixed solvent of propylene glycol methyl ether acetate / dibasic acid ester, and ultrasonically dispersing the mixture to obtain a F-CNTs slurry; S3: Slowly inject the F-CNTs slurry into the resin solution and mix evenly, then disperse at high speed for 15-25 minutes; S4: adding a leveling agent, a defoaming agent and a curing agent, and mixing them evenly to obtain a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating.

[0016] Furthermore, the preparation method of the fluorine-modified epoxy resin in step S1 comprises the following steps: S11: mixing a fluorine compound, BPO, and trifluorotoluene to form a mixed solution; S12: epoxy resin, ethylene glycol butyl ether and dodecyl mercaptan are mixed, heated to 100°C for dissolution, and then 40-50% of the total weight of the mixed solution is added dropwise, and the reaction is stirred for 0.5 h. The reaction is carried out in a reflux device, and then the remaining mixed solution is added dropwise and the reaction is continued for 1.5 h. After the reaction is completed, the solvent is removed under vacuum and then dried to obtain a fluorine-modified epoxy resin.

[0017] Furthermore, the mass of the BPO in step S11 is 1.0-1.5% of the fluorine compound.

[0018] Furthermore, in step S11, the mass of trifluorotoluene is 100-120% of the fluorine compound.

[0019] Furthermore, the mass of the dodecyl mercaptan in step S12 is 0.3-0.5% of the fluorine compound.

[0020] Furthermore, the vacuum environment temperature in step S12 is 60-70°C.

[0021] Furthermore, the high-speed dispersion rate in step S3 is 4000-6000 rpm.

[0022] Furthermore, the curing process of the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating is: curing at 30° C. for 4 hours, then curing at 80° C. for 2 hours, and finally curing at 120° C. for 1 hour.

[0023] The beneficial effects of the present invention are: This invention utilizes the addition of a fluorine compound (such as perfluorooctyl acrylate) and the introduction of long fluorine side chains into the epoxy resin. This utilizes the physical entanglement of the long fluorine chains within the epoxy resin matrix and the reinforcing effect of fluorinated carbon nanotubes to produce an epoxy resin with high hardness and toughness. Furthermore, the fluorine side chains form a chemical similarity with the fluorine groups on the surface of the fluorinated carbon nanotubes, improving the dispersibility of the fluorinated carbon nanotubes in the resin and addressing the common issues of insufficient toughness and nanofiller agglomeration in conventional epoxy coatings. The coating produced from this invention achieves an impact strength of 45-55 kJ / m², a 125% to 175% improvement over unmodified pure epoxy / fluorinated carbon nanotube composites. The coating also achieves a hardness of 3-4H, far exceeding the H level of the unmodified system. DETAILED DESCRIPTION

[0024] The present invention will be further described below with reference to the embodiments.

[0025] The fluorinated carbon nanotubes described in the following examples and comparative examples were purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd., XFM66, purity: ~ 90 at%, fluorine content: 48-58 wt%, outer diameter: 20-30 nm, length: 2-10 μm; The carbon nanotubes are purchased from Jiangsu Xianfeng Nanometer Material Technology Co., Ltd., XFM22, purity 95%, length 0.5-2 μm, diameter 20-30 nm; The epoxy resin 604 is purchased from Wuhan Jiyesheng Chemical Co., Ltd., epoxy equivalent weight: 800~1000 g / Eq, softening point: 85-106℃.

[0026] Example 1

[0027] (1) 1H, 1H-perfluoro-n-decyl methacrylate, BPO and trifluorotoluene are mixed according to the mass ratio of 100:1.5:120 to configure a mixed solution; (2) The epoxy resin 604, ethylene glycol butyl ether and dodecyl mercaptan are mixed according to the mass ratio of 100:5:0.5, heated to 105℃ to dissolve, and the mixed solution is taken according to the mass ratio of 100:5 of the epoxy resin 604 and the fluorine compound, then 50% of the mixed solution is added dropwise, stirred for 0.5h, the remaining mixed solution is added dropwise, and the reaction is continued for 1.5h. The reaction is carried out in a reflux device. After the reaction is completed, the solvent is removed in a vacuum environment of 60~70℃, and then dried to obtain a fluorine-modified epoxy resin; (3) The components are weighed as follows: fluorine-modified epoxy resin 100 parts, fluorinated carbon nanotubes 2 parts, Ancamide 350A 60 parts, propylene glycol methyl ether acetate / divalent acid ester mixed solvent 120 parts, the volume ratio of propylene glycol methyl ether acetate / divalent acid ester in the propylene glycol methyl ether acetate / divalent acid ester mixed solvent is 3:1, leveling agent BYK-331 0.3 parts, defoamer BYK-055 0.2 parts; (4) The fluorine-modified epoxy resin and 30% of the propylene glycol methyl ether acetate / divalent acid ester mixed solvent are stirred uniformly to obtain a resin slurry; (5) The fluorinated carbon nanotubes and the propylene glycol methyl ether acetate / divalent acid ester mixed solvent are mixed and ultrasonically dispersed to obtain an F-CNTs slurry; (6) The F-CNTs slurry is slowly injected into the resin liquid and mixed uniformly, and then dispersed at a high speed of 6000 rpm for 15 min; (7) BYK-331, BYK-055 and a curing agent are added and mixed uniformly to obtain a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating.

[0028] Example 2

[0029] The difference between Example 2 and Example 1 is that in step (2), "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:5" is changed to "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:3", and the rest is the same as Example 2.

[0030] Example 3

[0031] The difference between Example 3 and Example 1 is that in step (2), "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:5" is changed to "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:4", and the rest is the same as Example 2.

[0032] Example 4

[0033] The difference between Example 4 and Example 1 is that in step (3), "2 parts of fluorinated carbon nanotubes" is changed to "1 part of fluorinated carbon nanotubes", and the rest is the same as Example 2.

[0034] Example 5

[0035] The difference between Example 5 and Example 1 is that in step (3), "2 parts of fluorinated carbon nanotubes" is changed to "1.5 parts of fluorinated carbon nanotubes", and the rest is the same as Example 2.

[0036] Example 6

[0037] The difference between Example 6 and Example 1 is that in step (3), "2 parts of fluorinated carbon nanotubes" is changed to "2.5 parts of fluorinated carbon nanotubes", and the rest is the same as Example 2.

[0038] Comparative Example 1

[0039] (1) Weigh each component according to the following weight: 100 parts of epoxy resin 604, 2 parts of fluorinated carbon nanotubes, Ancamide 350A 60 parts, 120 parts of a propylene glycol methyl ether acetate / dibasic acid ester mixed solvent, wherein the volume ratio of propylene glycol methyl ether acetate to dibasic acid ester in the propylene glycol methyl ether acetate / dibasic acid ester mixed solvent is 3:1, Leveling agent BYK-331 0.3 parts, 0.2 parts of defoaming agent BYK-055; (2) Stirring the fluorine-modified epoxy resin and 30% by weight of a propylene glycol methyl ether acetate / dibasic acid ester mixed solvent to obtain a resin slurry; (3) mixing fluorinated carbon nanotubes and a mixed solvent of propylene glycol methyl ether acetate / dibasic acid ester, and ultrasonically dispersing the mixture to obtain a F-CNTs slurry; (4) Slowly inject the F-CNTs slurry into the resin solution and mix evenly, then disperse at a high speed of 4000-6000 rpm for 25 min; (7) BYK-331, BYK-055 and curing agent were added and mixed evenly to obtain a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating.

[0040] Comparative Example 2

[0041] The difference between Comparative Example 2 and Example 2 is that in step (2), "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:5" is changed to "measure the mixed solution according to the mass ratio of epoxy resin 604 and fluorine compound of 100:6", and the rest is the same as Example 2.

[0042] Comparative Example 3

[0043] The difference between Comparative Example 3 and Example 2 is that in step (3), "2 parts of fluorinated carbon nanotubes" is changed to "3 parts of fluorinated carbon nanotubes", and the rest is the same as Example 2.

[0044] Comparative Example 4

[0045] The difference between Comparative Example 4 and Example 2 is that in step (3), "2 parts of fluorinated carbon nanotubes" is changed to "0.5 parts of fluorinated carbon nanotubes", and the rest is the same as Example 2.

[0046] The coating was applied to a tinplate (120 mm × 50 mm) to a thickness of 150 μm and then cured at 30°C for 4 hours, 80°C for 2 hours, and finally at 120°C for 1 hour. The coating's impact strength was measured according to GB / T1843, and its hardness was tested according to GB / 6739. The test results are shown in Table 1.

[0047] Table 1 Impact strength and hardness test results of Examples and Comparative Examples

[0048] As shown in Table 1, the present invention improves the impact strength of the epoxy coating to 45-55 kJ / m² (a 125%–175% improvement over the unmodified system) by modifying the epoxy resin with a fluorinated compound, adding fluorinated carbon nanotubes, and optimizing the synergistic ratio of the fluorinated compound (4-5 parts) to the fluorinated carbon nanotubes (1-2.5 parts). This technology utilizes the physical entanglement of long fluorinated chains to enhance toughness and achieves uniform dispersion of the nanofiller through the similarity of fluorinated groups, balancing the brittleness of the epoxy resin with the agglomeration of the fluorinated carbon nanotubes. Excessive amounts of fluorinated compound (Comparative Example 2) or fluorinated carbon nanotubes (Comparative Example 3) can significantly reduce performance.

[0049] With the above-described preferred embodiments of the present invention as a guide, and with reference to the above description, relevant personnel are fully capable of making various changes and modifications without departing from the technical scope of this invention. The technical scope of this invention is not limited to the contents of the specification and must be determined according to the scope of the claims.

Claims

1. A fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating, characterized by: The components of the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating include, by weight: 100 parts of fluorine-modified epoxy resin, 1-2.5 parts of fluorinated carbon nanotubes, 40-60 parts of curing agent, 80-120 parts of propylene glycol methyl ether acetate / dibasic acid ester mixed solvent, 0.3 parts of leveling agent, 0.2 parts of defoaming agent; The fluorine-modified epoxy resin is prepared by reacting a fluorine compound and an epoxy resin; The fluorine compound is one of 1H,1H-perfluorooctyl acrylate and 1H,1H-perfluoro-n-decyl methacrylate.

2. The fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 1, characterized in that: The fluorine content of the fluorinated carbon nanotubes is 20-60 wt %; the curing agent is Ancamide 350A; the defoaming agent is BYK-055; and the leveling agent is BYK-331.

3. The fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 1, characterized in that: The volume ratio of propylene glycol methyl ether acetate to dibasic acid ester in the propylene glycol methyl ether acetate / dibasic acid ester mixed solvent is 3:

1.

4. A method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating according to any one of claims 1 to 3, characterized in that: The steps include: S1: stirring and mixing the fluorine-modified epoxy resin and propylene glycol methyl ether acetate / dibasic acid ester mixed solvent to obtain a resin slurry; S2: mixing fluorinated carbon nanotubes and a mixed solvent of propylene glycol methyl ether acetate / dibasic acid ester, and ultrasonically dispersing the mixture to obtain a F-CNTs slurry; S3: Slowly inject the F-CNTs slurry into the resin solution and mix evenly, then disperse at high speed for 15-25 minutes; S4: adding a leveling agent, a defoaming agent and a curing agent, and mixing them evenly to obtain a fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating.

5. The method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 4, characterized in that: The method for preparing the fluorine-modified epoxy resin in step S1 comprises the following steps: S11: mixing a fluorine compound, BPO, and trifluorotoluene to form a mixed solution; S12: epoxy resin, ethylene glycol butyl ether and dodecyl mercaptan are mixed, heated to 100°C for dissolution, and then 40-50% of the total weight of the mixed solution is added dropwise, and the reaction is stirred for 0.5 h. The reaction is carried out in a reflux device, and then the remaining mixed solution is added dropwise and the reaction is continued for 1.5 h. After the reaction is completed, the solvent is removed under vacuum and then dried to obtain a fluorine-modified epoxy resin.

6. The method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 5, characterized in that: The mass of the BPO in step S11 is 1.0-1.5% of the fluorine compound; In step S11, the mass of trifluorotoluene is 100-120% of the fluorine compound.

7. The method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 5, characterized in that: The mass of the dodecyl mercaptan in step S12 is 0.3-0.5% of the fluorine compound; The vacuum environment temperature in step S12 is 60-70°C.

8. The method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 4, characterized in that: The high-speed dispersion rate in step S3 is 4000-6000 rpm.

9. The method for preparing the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating as claimed in claim 4, characterized in that: The curing process of the fluorinated modified epoxy resin / fluorinated carbon nanotube composite coating is as follows: curing at 30° C. for 4 hours, then curing at 80° C. for 2 hours, and finally curing at 120° C. for 1 hour.

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