Long-acting antistatic coating and preparation method thereof

Abstract

The application provides a long-acting anti-static coating and a preparation method thereof. The coating comprises the following raw materials in parts by weight: modified multi-walled carbon nanotubes 0.1-2 parts, epoxy resin 20-50 parts, curing agent 1-2 parts, dispersing agent 0.5-5 parts, leveling agent 1-4 parts, and solvent 65-85 parts; the modified multi-walled carbon nanotubes are prepared by the following steps: adding multi-walled carbon nanotubes into a hydrogen peroxide solution, and reacting at 75-85 DEG C for 3-5 hours to obtain the modified multi-walled carbon nanotubes. The coating provided by the application uses epoxy resin as a resin matrix, uses hydrogen peroxide modified multi-walled carbon nanotubes as a conductive material, adds a curing agent, a dispersing agent and a leveling agent, and controls the content of each component; the modified multi-walled carbon nanotubes can be uniformly dispersed in the epoxy resin; after the coating is formed, the modified multi-walled carbon nanotubes are uniformly distributed between the structural grains and the structure interfaces of the coating and form a continuous conductive network structure, thereby giving the coating a long-acting anti-static effect.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a long-lasting antistatic coating and its preparation method. Background Technology

[0002] Static electricity is a widespread phenomenon in nature. In recent years, electrostatic charging has received increasing attention. While static electricity is utilized by humans, it also brings disasters to human life and production. Static electricity is generated when two substances come into close contact and then separate, with one substance transferring electrons to the other and becoming positively charged, while the other substance gains electrons and becomes negatively charged.

[0003] Static electricity can easily accumulate during the preparation and use of coatings. To eliminate the hazards caused by static electricity, the development of antistatic coatings has become a research hotspot, and antistatic coatings are increasingly favored in daily life. Most commercially available coatings achieve antistatic effects by applying a layer of conductive coating to the material surface. However, traditional polymer resin coatings have poor conductivity, and the resulting coating cannot provide excellent antistatic properties. They often accumulate static electricity due to friction from gases or dust in the air. As the static electricity accumulates to a certain level, it can cause electrostatic discharge, posing certain safety hazards and failing to meet people's demand for long-lasting antistatic effects. Therefore, there is an urgent need to find a coating with long-lasting antistatic effects. Summary of the Invention

[0004] To address the problem of poor long-term antistatic effect of coatings formed during the film formation of traditional polymer resin coatings, this invention provides a long-term antistatic coating and its preparation method.

[0005] According to a first aspect of the present invention, a long-lasting antistatic coating is provided, comprising the following raw materials in parts by weight: 0.1-2 parts of modified multi-walled carbon nanotubes, 20-50 parts of epoxy resin, 1-2 parts of curing agent, 0.5-5 parts of dispersant, 1-4 parts of leveling agent, and 65-85 parts of solvent; the modified multi-walled carbon nanotubes are prepared by the following steps: adding multi-walled carbon nanotubes to a hydrogen peroxide solution and reacting at 75-85°C for 3-5 hours to obtain modified multi-walled carbon nanotubes.

[0006] The long-lasting antistatic coating provided by this invention uses hydrogen peroxide-modified multi-walled carbon nanotubes as the conductive material. The modification of the multi-walled carbon nanotubes with hydrogen peroxide oxidizes them to obtain functional groups such as carboxyl and phenolic groups, reducing their aggregation. These modified multi-walled carbon nanotubes are then introduced into an epoxy resin, along with a curing agent, dispersant, and leveling agent. The proportions of each component are controlled within the specified range, allowing the modified multi-walled carbon nanotubes to be more uniformly dispersed in the epoxy resin. After film formation, the modified multi-walled carbon nanotubes are uniformly distributed between the structural grains and interfaces of the coating, forming a continuous and complete conductive network structure, thus giving the coating excellent long-lasting antistatic properties.

[0007] Preferably, the solid-liquid ratio of multi-walled carbon nanotubes to hydrogen peroxide solution is 1–3 g: 100–300 mL.

[0008] Preferably, the concentration of the hydrogen peroxide solution is 15–20 wt%.

[0009] Preferably, the multi-walled carbon nanotubes have a diameter of 10–50 nm and a length of 1–10 μm.

[0010] Preferably, the epoxy resin is a modified epoxy resin, which is prepared by the following steps: mixing the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate with the epoxy resin and reacting it at 140-160°C for 1-3 hours to obtain the modified epoxy resin.

[0011] Modifying epoxy resin with the amphiphilic triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate and applying it to coatings can further improve the dispersion performance of hydrogen peroxide-modified double-walled carbon nanotubes in epoxy resin. It also helps to improve the stability of the conductive network structure of the coating during film formation, thereby further improving the long-term antistatic effect of the coating. At the same time, the addition of the block copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate modified epoxy resin can also improve the wear resistance of the coating after film formation.

[0012] Preferably, the mass ratio of the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate to epoxy resin is 1:3 to 5.

[0013] Preferably, the curing agent is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 20-25°C for 1-3 hours to obtain the curing agent; the mass ratio of diglycidyl dimerase to isophorone diamine is 1-2:1-3.

[0014] In this invention, a triblock copolymer, polymethyl methacrylate-butyl acrylate-polymethyl methacrylate, is used to modify epoxy resin and add it to the coating. While the curing mechanism of the modified epoxy resin remains unchanged and its structure is not significantly affected after curing, the curing process is hindered, resulting in longer curing times, slower film formation, and more difficult cross-linking. Using diglycidyl dimerate to modify isophorone diamine as a curing agent in the long-lasting antistatic coating of this invention improves upon the long curing time and slow film formation of the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate modified epoxy resin. This makes the coating easier to cross-link and form a film during curing, facilitating the rapid formation of a conductive network structure, shortening the film formation time, and resulting in superior mechanical properties.

[0015] Preferably, the above-mentioned dimer acid diglycidyl ester is prepared by the following steps: the dimer acid, epichlorohydrin, and catalyst are mixed and reacted at 85-95°C for 1-2 hours, then cooled to 50-60°C, sodium hydroxide solution is added dropwise to the reaction system and kept at 50-60°C for 5-6 hours to obtain the dimer acid diglycidyl ester; the mass ratio is calculated as follows: dimer acid: epichlorohydrin: catalyst: sodium hydroxide solution = 1-2: 10-25: 0.01-0.05: 4-9.

[0016] Preferably, the concentration of the sodium hydroxide solution is 25–35 wt%.

[0017] Preferably, the catalyst includes at least one of anhydrous tin tetrachloride, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, and benzyltriethylammonium chloride.

[0018] Preferably, the leveling agent includes at least one of polysiloxane-modified polyether and polyester-modified polyether.

[0019] Preferably, the solvent is a mixture of alcohol and water in a mass ratio of 1:3 to 10.

[0020] Preferably, the alcohol is selected from at least one of isopropanol, n-propanol, ethanol, and methanol.

[0021] Preferably, the dispersant is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 2-3:1-2.

[0022] Naphthalene sulfonate and / or polyvinylpyrrolidone are used as dispersants in the coatings provided by this invention. The naphthalene molecule structure in naphthalene sulfonate can form strong van der Waals forces with the wall of the modified double-walled carbon nanotubes. The hydrophilic sulfonate segments in naphthalene sulfonate can disperse the modified double-walled carbon nanotubes in the solvent, while polyvinylpyrrolidone can effectively improve the dispersion ability of the modified double-walled carbon nanotubes in the alcohol system. Through the above effects, it is beneficial to improve the dispersibility of the modified double-walled carbon nanotubes in the coating.

[0023] Preferably, the above-mentioned long-lasting antistatic coating is prepared by the following steps:

[0024] S1. Modified multi-walled carbon nanotubes are mixed with a portion of solvent and then ground to obtain a dispersion of modified multi-walled carbon nanotubes.

[0025] S2. The modified multi-walled carbon nanotube dispersion is mixed with a dispersant and then subjected to a crushing process to obtain a mixed solution;

[0026] S3. The above mixed solution is mixed with the remaining solvent and then ground. During the grinding process, epoxy resin, curing agent and leveling agent are added to obtain a long-lasting antistatic coating. Detailed Implementation

[0027] The technical features of the technical solution provided by the present invention will be further 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. Based on the 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.

[0028] Example 1

[0029] A long-lasting antistatic coating comprises the following raw materials in parts by weight: 1 part modified multi-walled carbon nanotubes, 35 parts bisphenol A type epoxy resin, 1.5 parts curing agent, 3 parts dispersant, 2 parts leveling agent, and 75 parts solvent.

[0030] The modified multi-walled carbon nanotubes were prepared by the following steps: 2g of multi-walled carbon nanotubes with a particle size of 30nm and a length of 5μm were added to 200mL of hydrogen peroxide solution with a concentration of 18wt% and reacted at 80℃ for 4 hours to obtain the modified multi-walled carbon nanotubes.

[0031] The curing agent is isophorone diamine;

[0032] The dispersant was naphthalene sulfonate (purchased from Nanjing Jierun Technology Co., Ltd., brand name MorwetD-425);

[0033] The leveling agent is polyester-modified polyether;

[0034] The solvent is a mixture of ethanol and water in a mass ratio of 1:7;

[0035] The long-lasting antistatic coating provided in this embodiment is prepared through the following steps:

[0036] S1. The modified multi-walled carbon nanotubes are mixed with a portion of solvent (50% of the total mass of solvent) and then ground to obtain a modified multi-walled carbon nanotube dispersion.

[0037] S2. The modified multi-walled carbon nanotube dispersion is mixed with a dispersant and then subjected to a crushing process to obtain a mixed solution;

[0038] S3. The above mixed solution is mixed with the remaining solvent and then ground. During the grinding process, epoxy resin, curing agent and leveling agent are added to obtain a long-lasting antistatic coating.

[0039] Example 2

[0040] A long-lasting antistatic coating comprises the following raw materials in parts by weight: 0.1 parts modified multi-walled carbon nanotubes, 50 parts bisphenol A type epoxy resin, 1 part curing agent, 5 parts dispersant, 1 part leveling agent, and 65 parts solvent.

[0041] The modified multi-walled carbon nanotubes were prepared by the following steps: 1 g of multi-walled carbon nanotubes with a particle size of 10 nm and a length of 10 μm were added to a 20 wt% hydrogen peroxide solution (300 mL) and reacted at 75 °C for 5 hours to obtain the modified multi-walled carbon nanotubes.

[0042] The curing agent is isophorone diamine;

[0043] The dispersant was naphthalene sulfonate (purchased from Nanjing Jierun Technology Co., Ltd., brand name MorwetD-425);

[0044] The leveling agent is polyester-modified polyether;

[0045] The solvent is a mixture of ethanol and water in a mass ratio of 1:3.

[0046] The long-lasting antistatic coating provided in this embodiment is prepared through the following steps:

[0047] S1. The modified multi-walled carbon nanotubes are mixed with a portion of solvent (50% of the total mass of solvent) and then ground to obtain a modified multi-walled carbon nanotube dispersion.

[0048] S2. The modified multi-walled carbon nanotube dispersion is mixed with a dispersant and then subjected to a crushing process to obtain a mixed solution;

[0049] S3. The above mixed solution is mixed with the remaining solvent and then ground. During the grinding process, epoxy resin, curing agent and leveling agent are added to obtain a long-lasting antistatic coating.

[0050] Example 3

[0051] A long-lasting antistatic coating comprises the following raw materials in parts by weight: 2 parts modified multi-walled carbon nanotubes, 20 parts bisphenol A type epoxy resin, 2 parts curing agent, 0.5 parts dispersant, 4 parts leveling agent, and 85 parts solvent.

[0052] The modified multi-walled carbon nanotubes were prepared by the following steps: 3g of multi-walled carbon nanotubes with a particle size of 50nm and a length of 1μm were added to 100mL of hydrogen peroxide solution with a concentration of 20wt% and reacted at 85℃ for 3 hours to obtain the modified multi-walled carbon nanotubes.

[0053] The curing agent is isophorone diamine;

[0054] The dispersant was naphthalene sulfonate (purchased from Nanjing Jierun Technology Co., Ltd., brand name MorwetD-425);

[0055] The leveling agent is polyester-modified polyether;

[0056] The solvent is a mixture of ethanol and water in a mass ratio of 1:10;

[0057] The long-lasting antistatic coating provided in this embodiment is prepared through the following steps:

[0058] S1. The modified multi-walled carbon nanotubes are mixed with a portion of solvent (50% of the total mass of solvent) and then ground to obtain a modified multi-walled carbon nanotube dispersion.

[0059] S2. The modified multi-walled carbon nanotube dispersion is mixed with a dispersant and then subjected to a crushing process to obtain a mixed solution;

[0060] S3. The above mixed solution is mixed with the remaining solvent and then ground. During the grinding process, epoxy resin, curing agent and leveling agent are added to obtain a long-lasting antistatic coating.

[0061] Example 4

[0062] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that modified bisphenol A epoxy resin is used instead of bisphenol A epoxy resin.

[0063] The modified bisphenol A epoxy resin used in this embodiment was prepared by the following steps: the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate was mixed with bisphenol A epoxy resin at a mass ratio of 1:4 and reacted at 150°C for 2 hours to obtain the modified bisphenol A epoxy resin.

[0064] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0065] Example 5

[0066] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that modified bisphenol A epoxy resin is used instead of bisphenol A epoxy resin.

[0067] The modified bisphenol A epoxy resin used in this embodiment was prepared by the following steps: the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate was mixed with bisphenol A epoxy resin at a mass ratio of 1:3 and reacted at 140°C for 3 hours to obtain the modified bisphenol A epoxy resin.

[0068] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0069] Example 6

[0070] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that modified bisphenol A epoxy resin is used instead of bisphenol A epoxy resin.

[0071] The modified bisphenol A epoxy resin used in this embodiment was prepared by the following steps: the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate was mixed with bisphenol A epoxy resin at a mass ratio of 1:5 and reacted at 160°C for 1 hour to obtain the modified bisphenol A epoxy resin.

[0072] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0073] Example 7

[0074] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the curing agent used is different.

[0075] The curing agent used in this embodiment is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 23°C for 2 hours to obtain the curing agent, wherein the mass ratio of diglycidyl dimerase to isophorone diamine is 1.5:2.

[0076] The dimer acid diglycidyl ester is prepared by the following steps: dimer acid, epichlorohydrin and benzyltriethylammonium chloride catalyst are mixed and reacted at 90°C for 1.5 hours, then cooled to 55°C, a 30wt% sodium hydroxide solution is added dropwise to the reaction system and kept at 55°C for 5.5 hours to obtain dimer acid diglycidyl ester;

[0077] Based on the mass ratio, the ratio of dimer acid: epichlorohydrin: catalyst: sodium hydroxide solution is 1.5:20:0.03:7.

[0078] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0079] Example 8

[0080] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the curing agent used is different.

[0081] The curing agent used in this embodiment is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 20°C for 3 hours to obtain the curing agent, wherein the mass ratio of diglycidyl dimerase to isophorone diamine is 1:3.

[0082] The dimer acid diglycidyl ester is prepared by the following steps: dimer acid, epichlorohydrin and benzyltriethylammonium chloride catalyst are mixed and reacted at 85°C for 2 hours, then cooled to 50°C, a 25wt% sodium hydroxide solution is added dropwise to the reaction system and kept at 50°C for 6 hours to obtain dimer acid diglycidyl ester.

[0083] Based on the mass ratio, the ratio of dimer acid: epichlorohydrin: catalyst: sodium hydroxide solution is 1:10:0.01:4.

[0084] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0085] Example 9

[0086] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the curing agent used is different.

[0087] The curing agent used in this embodiment is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 25°C for 1 hour to obtain the curing agent, wherein the mass ratio of diglycidyl dimerase to isophorone diamine is 2:1.

[0088] The dimer acid diglycidyl ester is prepared by the following steps: dimer acid, epichlorohydrin and benzyltriethylammonium chloride catalyst are mixed and reacted at 95°C for 1 hour, then cooled to 60°C, a 35wt% sodium hydroxide solution is added dropwise to the reaction system and kept at 60°C for 5 hours to obtain dimer acid diglycidyl ester.

[0089] Based on the mass ratio, the ratio of dimer acid: epichlorohydrin: catalyst: sodium hydroxide solution is 2:25:0.05:9.

[0090] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0091] Example 10

[0092] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the dispersant used is different. The dispersant used in this embodiment is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 2.5:2.

[0093] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0094] Example 11

[0095] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the dispersant used is different. The dispersant used in this embodiment is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 3:1.

[0096] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0097] Example 12

[0098] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the dispersant used is different. The dispersant used in this embodiment is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 2:1.5.

[0099] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0100] Example 13

[0101] This embodiment provides a long-lasting antistatic coating. Compared with Embodiment 1, the difference in composition is that the preparation method of the long-lasting antistatic coating is different.

[0102] The long-lasting antistatic coating provided in this embodiment is prepared through the following steps:

[0103] S1. Modified multi-walled carbon nanotubes, solvent, and dispersion are mixed and then ground and crushed to obtain a mixed solution;

[0104] S2. Add epoxy resin, curing agent and leveling agent to the above mixed solution, mix evenly, and obtain a long-lasting antistatic coating.

[0105] Apart from the differences mentioned above, the materials, formulation ratios, and preparation operations used in this embodiment are strictly consistent with those in Example 1.

[0106] Example 14

[0107] A long-lasting antistatic coating comprises the following raw materials in parts by weight: 1 part modified multi-walled carbon nanotubes, 35 parts modified bisphenol A epoxy resin, 1.5 parts curing agent, 3 parts dispersant, 2 parts leveling agent, and 75 parts solvent.

[0108] The modified multi-walled carbon nanotubes were prepared by the following steps: 2g of multi-walled carbon nanotubes with a particle size of 30nm and a length of 5μm were added to 200mL of hydrogen peroxide solution with a concentration of 18wt% and reacted at 80℃ for 4 hours to obtain the modified multi-walled carbon nanotubes.

[0109] Modified bisphenol A epoxy resin was prepared by the following steps: triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate was mixed with bisphenol A epoxy resin at a mass ratio of 1:4 and reacted at 150°C for 2 hours to obtain modified bisphenol A epoxy resin.

[0110] The curing agent is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 23°C for 2 hours to obtain the curing agent, wherein the mass ratio of diglycidyl dimerase to isophorone diamine is 1.5:2;

[0111] Dimeric acid diglycidyl ester was prepared by the following steps: Dimeric acid, epichlorohydrin, and benzyltriethylammonium chloride catalyst were mixed and reacted at 90°C for 1.5 hours. The mixture was then cooled to 55°C, and a 30wt% sodium hydroxide solution was added dropwise to the reaction system. The mixture was then kept at 55°C for 5.5 hours to obtain dimeric acid diglycidyl ester. The mass ratio of dimeric acid: epichlorohydrin: catalyst: sodium hydroxide solution was 1.5:20:0.03:7.

[0112] The dispersant is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 2.5:2;

[0113] The leveling agent is polyester-modified polyether;

[0114] The solvent is a mixture of ethanol and water in a mass ratio of 1:7;

[0115] The long-lasting antistatic coating provided in this embodiment is prepared through the following steps:

[0116] S1. The modified multi-walled carbon nanotubes are mixed with a portion of solvent (50% of the total mass of solvent) and then ground to obtain a modified multi-walled carbon nanotube dispersion.

[0117] S2. The modified multi-walled carbon nanotube dispersion is mixed with a dispersant and then subjected to a crushing process to obtain a mixed solution;

[0118] S3. The above mixed solution is mixed with the remaining solvent and then ground. During the grinding process, epoxy resin, curing agent and leveling agent are added to obtain a long-lasting antistatic coating.

[0119] Comparative Example 1

[0120] This comparative example provides a long-lasting antistatic coating. Compared with Example 1, the difference in composition is that an equal amount of single-walled carbon nanotubes are used instead of modified multi-walled carbon nanotubes. Apart from the above differences, the materials, formulation ratios, and preparation procedures used in this comparative example are strictly consistent with those in Example 1.

[0121] Comparative Example 2

[0122] This comparative example provides a long-lasting antistatic coating. Compared with Example 1, the difference in composition is that an equal amount of unmodified multi-walled carbon nanotubes are used instead of modified multi-walled carbon nanotubes. Apart from the above differences, the materials, formulation ratios, and preparation procedures used in this comparative example are strictly consistent with those in Example 1.

[0123] Comparative Example 3

[0124] This comparative example provides a long-lasting antistatic coating. The difference between this and Example 1 is that a water-based hyperbranched polyester resin (purchased from Guangzhou Chanxie Polymer Co., Ltd., brand name WP-993) is used instead of epoxy resin. Apart from the above differences, the materials, formulation ratios, and preparation procedures used in this comparative example are strictly consistent with those in Example 1.

[0125] Test case

[0126] 1. Participants

[0127] This test example uses the long-lasting antistatic coatings prepared in Examples 1-14 and Comparative Examples 1-3 as test objects to conduct relevant performance tests.

[0128] 2. Test Content

[0129] (1) Antistatic properties

[0130] Refer to industry standard SJ / T 11294-2018.

[0131] (2) Wear resistance

[0132] Long-lasting antistatic coatings prepared in Examples 1-14 and Comparative Examples 1-3 were applied to the surface of fiber-reinforced cement boards with a diameter of 25 mm conforming to GB / T 9271-2008 "Standard Test Panels for Paints and Varnishes". After being placed in an environment of 25°C and 50% relative humidity for 24 hours, a paint film with a thickness of 250 μm was obtained. The abrasion resistance of the coatings was tested according to GB / T1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method" at a temperature of 25°C and a relative humidity of 50%, with the abrasion tester rotating at 60 r / min and the test time being 3 min. The abrasion resistance of the coatings was expressed as wear mass loss (unit: mg), calculated using the following formula: Wear mass loss = Initial test panel mass - Test panel mass after test.

[0133] (3) Mechanical properties

[0134] Tensile strength and elongation at break were tested in accordance with national standard GB / T16777-1997, and tear strength was tested in accordance with national standard GB / T529-1999.

[0135] (4) Surface drying time

[0136] Refer to national standard GB / T 1728-1979.

[0137] 3. Experimental Results

[0138] Table 1 Performance test results of long-lasting antistatic coatings

[0139]

[0140] The performance test results of the long-lasting antistatic coatings provided in Examples 1-14 and Comparative Examples 1-3 are shown in Table 1.

[0141] The surface resistivity of the long-lasting antistatic coatings provided in Examples 1-3 after film formation is (2.5-2.9)×10⁻⁶. 5 Within this scope, the main reason is that the long-lasting antistatic coatings provided in Examples 1-3 use modified multi-walled carbon nanotubes as conductive fillers, which are introduced into the epoxy resin. At the same time, curing agents, dispersants, and leveling agents are added, and the components are controlled within a specific range, so that the modified multi-walled carbon nanotubes can be more uniformly dispersed in the epoxy resin. After the long-lasting antistatic coating provided by the present invention is formed, the modified multi-walled carbon nanotubes can be uniformly distributed between the structural grains and structural interfaces of the coating, forming a continuous and complete conductive network structure, giving the coating excellent long-lasting antistatic effect.

[0142] Compared to Example 1, the long-lasting antistatic coating provided in Comparative Example 1 used unmodified single-walled carbon nanotubes as conductive fillers, the long-lasting antistatic coating provided in Comparative Example 2 used unmodified multi-walled carbon nanotubes as conductive fillers, and the long-lasting antistatic coating provided in Comparative Example 3 used water-based hyperbranched polyester resin as the resin matrix. Test results showed that the surface resistance of the coatings provided in Comparative Examples 1-3 after film formation was higher than that in Example 1, indicating that the antistatic effect was worse than that in Example 1.

[0143] Compared with Example 1, the epoxy resin used in the long-lasting antistatic coatings provided in Examples 4 to 6 was modified by a triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate. The test results showed that the antistatic effect of the coating after film formation of the long-lasting antistatic coatings provided in Examples 4 to 6 was better than that of Example 1, specifically reflected in its surface resistance being much lower than that of Example 1.

[0144] Among all the tested objects, the long-lasting antistatic coating provided in Example 14 used multi-walled carbon nanotubes modified with hydrogen peroxide as conductive filler, epoxy resin modified with triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate as resin matrix, isophorone diamine modified with dimer acid diglycidyl ester as curing agent, and dispersant composed of naphthalene sulfonate and polyvinylpyrrolidone. The test results showed that the long-lasting antistatic coating provided in Example 14 had the lowest surface resistance after film formation, and the best antistatic effect, mechanical properties and wear resistance.

[0145] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention, but such modifications or substitutions are all within the scope of protection of the present invention.

Claims

1. A long-lasting antistatic coating, characterized in that, The raw materials include the following parts by weight: 0.1-2 parts of modified multi-walled carbon nanotubes, 20-50 parts of modified epoxy resin, 1-2 parts of curing agent, 0.5-5 parts of dispersant, 1-4 parts of leveling agent, and 65-85 parts of solvent. The modified multi-walled carbon nanotubes are prepared by the following steps: adding multi-walled carbon nanotubes to hydrogen peroxide solution and reacting at 75~85℃ for 3~5 hours to obtain the modified multi-walled carbon nanotubes. The modified epoxy resin is prepared by the following steps: mixing triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate with epoxy resin and reacting at 140~160℃ for 1~3 hours to obtain the modified epoxy resin. The curing agent is prepared by the following steps: diglycidyl dimerase is added dropwise to isophorone diamine and reacted at 20-25°C for 1-3 hours to obtain the curing agent, wherein the mass ratio of diglycidyl dimerase to isophorone diamine is 1-2:1-3.

2. The long-lasting antistatic coating as described in claim 1, characterized in that: The solid-liquid ratio of the multi-walled carbon nanotubes to the hydrogen peroxide solution is 1~3g:100~300mL. And / or, The concentration of the hydrogen peroxide solution is 15-20 wt%.

3. The long-lasting antistatic coating as described in claim 1, characterized in that: The multi-walled carbon nanotubes have a diameter of 10~50nm and a length of 1~10μm.

4. The long-lasting antistatic coating as described in claim 1, characterized in that: The mass ratio of the triblock copolymer polymethyl methacrylate-butyl acrylate-polymethyl methacrylate to the epoxy resin is 1:3~5.

5. The long-lasting antistatic coating as described in claim 1, characterized in that, The dimer acid diglycidyl ester was prepared by the following steps: the dimer acid, epichlorohydrin and catalyst were mixed and reacted at 85-95°C for 1-2 hours, the temperature was lowered to 50-60°C, sodium hydroxide solution was added dropwise to the reaction system and the mixture was kept at 50-60°C for 5-6 hours to obtain the dimer acid diglycidyl ester. The mass ratio of the dimer acid to the epichlorohydrin to the catalyst to the sodium hydroxide solution is 1-2:10-25:0.01-0.05:4-9.

6. The long-lasting antistatic coating as described in claim 5, characterized in that: The catalyst includes at least one of anhydrous tin tetrachloride, tetrabutylammonium bromide, hexadecyltrimethylammonium bromide, and benzyltriethylammonium chloride.

7. The long-lasting antistatic coating as described in claim 1, characterized in that: The dispersant is a mixture of naphthalene sulfonate and polyvinylpyrrolidone in a mass ratio of 2-3:1-2.

8. The long-lasting antistatic coating as described in claim 1, characterized in that, It is prepared through the following steps: S1. The modified multi-walled carbon nanotubes are mixed with a portion of the solvent and then ground to obtain a modified multi-walled carbon nanotube dispersion. S2. The modified multi-walled carbon nanotube dispersion is mixed with the dispersant and then subjected to a crushing process to obtain a mixed solution; S3. The mixed solution is mixed with the remaining solvent and then ground. During the grinding process, the modified epoxy resin, the curing agent and the leveling agent are added to obtain the long-lasting antistatic coating.

Images