High-solid nano fluorocarbon primer

Abstract

The invention relates to the technical field of coatings, in particular to a high-solid nano fluorocarbon primer, a first component in the high-solid nano fluorocarbon primer is composed of fluorocarbon resin, a flatting agent, a defoaming agent, a dispersing agent, a filler, a pigment, an auxiliary, a thixotropic agent and a solvent, and a second component is an aliphatic isocyanate polymer; wherein the auxiliary agent is composed of modified carbon nanotubes and fluorinated nanocellulose, due to the electrical conductivity of the carbon nanotubes, the loaded BYK-306 can better exert the leveling effect, and the polyamide wax can better utilize intermolecular hydrogen bonds in the modified carbon nanotubes to form a network structure, so that the occurrence of an upside-down phenomenon is prevented; the primer has relatively strong adsorption affinity to metal ions, so that the primer can be better attached to a substrate; moreover, a-CF3 group introduced to the surface of the fluorinated nanocellulose can reduce the surface energy and enhance the compatibility with fluorocarbon resin, the overall leveling property of the fluorocarbon primer is further improved, and the fluorocarbon primer has a wide application prospect.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to a high-solid nano fluorocarbon primer. Background Art

[0002] Fluorocarbon coatings refer to coatings with fluorine resin as the main film-forming substance. In Europe and the United States, coatings based on fluoroolefin polymers or copolymers of fluoroolefins and other monomers are called "fluorocarbon coatings", while in my country they are often called "fluorine-containing coatings". The development of fluorocarbon coatings has gone through several stages, from the initial hot melt type, to the solvent soluble type, to the room temperature / room temperature curing type (cross-linking type), and then to water-based / high solids coatings, and finally to today's powder coatings. Each step of progress is based on scientific progress and technological innovation.

[0003] Fluorocarbon primer is a group made of fluorine-modified polymer resin as the main base material, with various corrosion-resistant pigments, fillers, additives and solvents added and then ground and dispersed; it is widely used in cement mortar, concrete, brick walls and asbestos boards on the interior and exterior walls of buildings.

[0004] Fluorocarbon primer has excellent properties due to the high electronegativity of the introduced fluorine element and the strong carbon-fluorine bond energy. It has weather resistance, heat resistance, low temperature resistance, chemical resistance, and unique non-stick and low friction properties. After decades of rapid development, fluorine coatings have been widely used in various fields such as construction, chemical industry, electrical and electronic industry, machinery industry, aerospace industry, and household products. With the development of current technology, the preparation and research and development of fluorocarbon coatings have become more and more extensive, which has further improved the performance of fluorocarbon coatings.

[0005] At present, countries around the world are paying more and more attention to environmental protection and green development. At present, long-lasting fluorocarbon coatings are still mainly solvent-based, with high VOC emissions, which pose a certain degree of threat to the environment and the health of construction workers. In addition, the recent policy of levying consumption tax on coatings has made it urgent for industry insiders to solve the problem of how to reduce VOC emissions and losses during construction while ensuring the protective effect of coatings. Water-based fluorocarbon coatings have low VOCs, but due to factors such as synthesis technology and performance, the application of water-based fluorocarbon coatings in the field of industrial coatings is still very limited. Powder fluorocarbon coatings have no VOC emissions during the production and coating process, which meets environmental protection requirements, but special equipment is required during the construction process, and high-temperature drying is required, which is not suitable for the coating of large structural parts. High-solid fluorocarbon coatings can be used to coat large and complex structures indoors or outdoors, and have a high tolerance to ambient temperature and humidity, making them a green industrial anti-corrosion coating that can be widely promoted.

[0006] Prior art documents, such as patent technology document CN105238170A, disclose a high-solid fluorocarbon coating formula and a preparation method thereof. The fluorocarbon coating in the invention is prepared from low-polymerization degree polytrifluorochloroethylene resin, low-viscosity hydroxy polysiloxane resin, fluorine-modified hydroxy vinyl resin and other polymers, high-activity low-viscosity cross-linking agent, organic and inorganic coloring pigments, inorganic fillers, organic solvents, dispersants, thickeners, defoaming agents and leveling agents. The fluorocarbon coating prepared by the invention has a high solid content and can greatly reduce the emission of organic solvents, but the overall leveling property of the fluorocarbon material needs to be further improved.

[0007] Therefore, according to the above-mentioned related technologies, it is urgent to develop a high-solid nano fluorocarbon primer. Summary of the invention

[0008] In view of this, the purpose of the present invention is to provide a high-solid nano-fluorocarbon primer to solve the problem of poor fluidity of high-solid fluorocarbon coatings in electrostatic spraying in the prior art.

[0009] Based on the above purpose, the present invention provides a high-solid nano-fluorocarbon primer, comprising the following raw materials in parts by weight:

[0010] The first component is 32-40g; the second component is 3-4g;

[0011] The first component is prepared from the following raw materials in parts by weight:

[0012] Fluorocarbon resin 95-108g; leveling agent 0.28-0.35g; defoamer 0.6-0.72g; dispersant 1.8-2.5g; filler 1-3g; pigment 0.5-1g; thixotropic agent 2.6-3g; additive 0.3-1.2g; solvent 18-23g;

[0013] The second component is an aliphatic isocyanate polymer;

[0014] The aliphatic isocyanate polymer is obtained by mixing N3390 and Basonat HI-190 in a mass ratio of 8-14:4-7;

[0015] The fluorocarbon resin is obtained by mixing HLR-6 and HLR-670 in a mass ratio of 1:2-2.7;

[0016] The auxiliary agent is obtained by mixing modified carbon nanotubes and fluorinated nanocellulose in a mass ratio of 23-30:7-12;

[0017] The modified carbon nanotubes are prepared from carbon nanotubes, heptadecafluorodecyltriethoxysilane, BYK-306 and polyamide wax;

[0018] The solvent is obtained by mixing propylene glycol methyl ether acetate, dipropylene glycol dimethyl ether and butyl acetate in a mass ratio of 8-12:5-8:2-4.

[0019] Preferably, the preparation method of the modified carbon nanotubes is as follows:

[0020] S1. Add a 70% concentrated nitric acid solution to the carbon nanotubes and boil for 30-40 minutes, place at 40°C for 4-5 hours under ultrasonic vibration, and then repeatedly centrifuge and precipitate with deionized water until the solution becomes neutral, and then dry to obtain compound A;

[0021] S2. Add ethanol and water in a volume ratio of 9:1 to heptadecafluorodecyltriethoxysilane in a mixed solution A, then add acetic acid dropwise to adjust the solution pH to 3-4, then add compound A, ultrasonically disperse for 30-40 min, stir at 55-62 ° C for 4-5 h, then centrifuge, wash with deionized water, and dry to obtain compound B;

[0022] S3. Add tetrahydrofuran to compound B, mix well, then add leveling agent BYK-306 and polyamide wax, stir at 40-50° C. for 2.5-3.5 hours, filter, wash with ethanol aqueous solution, and dry to obtain modified carbon nanotubes.

[0023] Preferably, the ratio of the carbon nanotubes to the concentrated nitric acid solution in S1 is 0.2-0.32 g: 180-230 mL;

[0024] The temperature during the drying is 85-95°C.

[0025] Preferably, the usage ratio of heptadecafluorodecyltriethoxysilane, mixed solution A and compound A in S2 is 4.5-5.5 g:110-125 mL:9.8-10.6 g;

[0026] The drying temperature is 60-70°C and the drying time is 25-30 minutes.

[0027] Preferably, the mass ratio of the compound B, tetrahydrofuran, leveling agent BYK-306 and polyamide wax in S3 is 12-16; 30-40: 6-9: 2-5;

[0028] The drying temperature is 55-65° C. and the drying time is 35-40 minutes.

[0029] Preferably, the preparation method of the fluorinated nanocellulose is as follows:

[0030] Nanocellulose was added to dimethyl sulfoxide, stirred evenly, and placed in a plasma reactor. Carbon tetrafluoride was used as the plasma gas, and the plasma was evacuated by a vacuum pump until the initial vacuum degree was less than 3×10-3 Pa, plasma treatment is carried out in a dielectric barrier discharge chamber, and then washed with ethanol 2-3 times and dried to obtain fluorinated nanocellulose.

[0031] Preferably, the mass ratio of dimethyl sulfoxide to nanocellulose is 25-32:5-11; the plasma treatment time is 15-20 min, the power is 110-125 W, and the gas flow rate of carbon tetrafluoride is 4-7 mL / min;

[0032] The drying temperature is 50-60°C and the drying time is 20-25 minutes.

[0033] Preferably, the leveling agent is BYK-306;

[0034] The defoamer is AFCONA-2722;

[0035] The filler is any one of calcium carbonate and white carbon black.

[0036] Preferably, the dispersant is any one of BASF4401 and BYK161;

[0037] The pigment is diamond titanium dioxide;

[0038] The thixotropic agent is organic bentonite.

[0039] Preferably, the method for preparing the first component comprises the following steps:

[0040] Add fluorocarbon resin, leveling agent, defoamer, dispersant, filler, pigment, additive and thixotropic agent into a reaction kettle respectively, then add solvent, disperse at high speed until uniform, grind with a horizontal grinder 2-3 times until the fineness is less than 30 μm, to obtain a first component; mix the first component and the second component to obtain a fluorocarbon resin;

[0041] The speed of the high-speed dispersion is 800-1000 r / min, and the stirring time is 25-35 min.

[0042] Beneficial effects of the present invention:

[0043] The invention provides a high-solid nano fluorocarbon primer. The invention mixes a fluorocarbon resin, a leveling agent, a defoamer, a dispersant, a filler, a pigment, an auxiliary agent, a thixotropic agent and a solvent to obtain a first component, and then mixes the first component with an aliphatic isocyanate polymer as a second component to prepare a high-solid fluorocarbon primer with good leveling during electrostatic spraying. In the invention, the auxiliary agent consists of modified carbon nanotubes and fluorinated nanocellulose. During electrostatic spraying, due to the conductivity of the carbon nanotubes, the loaded leveling agent BYK-306 can better exert the leveling effect. The polyamide wax contains a variety of active groups. In the modified carbon nanotubes, intermolecular hydrogen bonds can be better used to form a network structure to prevent the occurrence of an inverted hanging phenomenon. The amide groups therein have a strong adsorption affinity for metal ions, that is, the fluorocarbon primer has good adhesion to a metal substrate.

[0044] Moreover, on the one hand, the surface of fluorinated nanocellulose will show slight changes in roughness, which is beneficial to improve the spreading ability of the paint film and avoid the occurrence of sagging; on the other hand, the -CF 3 The group can reduce the surface energy and enhance the compatibility with fluorocarbon resin. The overall leveling property of fluorocarbon primer is further improved. Compared with the existing technology, it has broad application prospects. DETAILED DESCRIPTION

[0045] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0046] The sources and properties of some of the raw materials used in the present invention are as follows:

[0047] N3390 was purchased from the Shenzhen branch of Guangzhou Haoyi Chemical Technology Co., Ltd.; Basonat HI-190 was purchased from BASF; rutile titanium dioxide was purchased from Jinan Yuxing Chemical Co., Ltd.; organic bentonite was purchased from Shijiazhuang Shuoheng New Materials Technology Co., Ltd.; HLR-6 was purchased from Sanai Fu Chemical Co., Ltd.; HLR-670 was purchased from Shandong Huafu Co., Ltd.; AFCONA-2722 was purchased from Efcona; nanocellulose was purchased from Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; BASF4401 was purchased from BASF; organic bentonite was purchased from Zhejiang Fenghong New Materials Co., Ltd.; and calcium carbonate was purchased from Xuancheng Huaxin Chemical Co., Ltd.

[0048] Embodiment 1: A method for preparing a high-solid nano-fluorocarbon primer comprises the following steps:

[0049] S1. Add 180 mL of 70% concentrated nitric acid solution to 0.2 g of carbon nanotubes and boil for 30 min, then place under ultrasonic oscillation at 40 ° C for 4 h, centrifuge and precipitate repeatedly with deionized water until the solution becomes neutral, and dry at 85 ° C to obtain compound A;

[0050] S2. Add 110 mL of a mixed solution A of ethanol and water in a volume ratio of 9:1 to 4.5 g of heptafluorodecyltriethoxysilane, then add acetic acid dropwise to adjust the solution pH to 3, then add 9.8 g of compound A, and after ultrasonic dispersion for 30 min, stir at 55 ° C for 4 h, centrifuge, wash with deionized water, and dry at 60 ° C for 25 min to obtain compound B;

[0051] S3. Add 30 g of tetrahydrofuran to 12 g of compound B, mix well, then add 6 g of leveling agent BYK-306 and 2 g of polyamide wax, stir at 40 ° C for 2.5 h, filter, wash with ethanol aqueous solution, and dry at 55 ° C for 25 min to obtain modified carbon nanotubes;

[0052] S4. Add 5 g of nanocellulose to 25 g of dimethyl sulfoxide, stir evenly, place in a plasma reactor, use carbon tetrafluoride as plasma gas, and evacuate by vacuum pump until the initial vacuum degree is less than 3×10 -3 Pa, plasma treatment was carried out in a dielectric barrier discharge chamber, the plasma treatment time was set to 15 min, the power was 110 W, the gas flow rate of carbon tetrafluoride was 4 mL / min, and then washed with ethanol twice, and dried at 50 ° C for 20 min to obtain fluorinated nanocellulose;

[0053] S5. 8 g of propylene glycol methyl ether acetate, 5 g of dipropylene glycol dimethyl ether and 2 g of butyl acetate were mixed to obtain a solvent; 1 g of HLR-6 and 2 g of HLR-670 were mixed to obtain a fluorocarbon resin; 23 g of modified carbon nanotubes and 7 g of fluorinated nanocellulose were mixed to obtain an additive; 8 g of N3390 and 4 g of Basonat HI-190 were mixed to obtain a second component;

[0054] S6. 95g of fluorocarbon resin, 0.28g of BYK-306, 0.6g of AFCONA-2722, 1.8g of BYK161, 1g of calcium carbonate, 0.5g of diamond titanium dioxide, 0.3g of additives and 2.6g of organic bentonite were added to the reactor, and then 18g of solvent was added, and the mixture was dispersed at a rate of 800r / min for 25min, and ground twice with a horizontal grinder until the fineness was less than 30μm to obtain a first component;

[0055] S7. Mix 32 g of the first component and 3 g of the second component to obtain a fluorocarbon resin.

[0056] Embodiment 2: A method for preparing a high-solid nano-fluorocarbon primer comprises the following steps:

[0057] S1. Add 200 mL of 70% concentrated nitric acid solution to 0.24 g of carbon nanotubes and boil for 33 min, then place under ultrasonic oscillation at 40 ° C for 4.5 h, centrifuge and precipitate repeatedly with deionized water until the solution becomes neutral, and dry at 88 ° C to obtain compound A;

[0058] S2. Add 115 mL of a mixed solution A of ethanol and water in a volume ratio of 9:1 to 4.8 g of heptafluorodecyltriethoxysilane, then add acetic acid dropwise to adjust the pH of the solution to 3, then add 10 g of compound A, and after ultrasonic dispersion for 33 min, stir at 58 ° C for 4.5 h, centrifuge, wash with deionized water, and dry at 63 ° C for 25 min to obtain compound B;

[0059] S3. 33 g of tetrahydrofuran was added to 14 g of compound B, mixed evenly, and then 7 g of leveling agent BYK-306 and 3 g of polyamide wax were added, stirred at 43 ° C for 3 h, filtered, washed with ethanol aqueous solution, and dried at 58 ° C for 28 min to obtain modified carbon nanotubes;

[0060] S4. Add 7 g of nanocellulose to 28 g of dimethyl sulfoxide, stir evenly, place in a plasma reactor, use carbon tetrafluoride as plasma gas, and evacuate by vacuum pump until the initial vacuum degree is less than 3×10 -3 Pa, plasma treatment was carried out in a dielectric barrier discharge chamber, the plasma treatment time was set to 17 min, the power was 115 W, the gas flow rate of carbon tetrafluoride was 5 mL / min, and then washed with ethanol twice, and dried at 53 ° C for 23 min to obtain fluorinated nanocellulose;

[0061] S5. 9 g of propylene glycol methyl ether acetate, 6 g of dipropylene glycol dimethyl ether and 3 g of butyl acetate were mixed to obtain a solvent; 1 g of HLR-6 and 2.2 g of HLR-670 were mixed to obtain a fluorocarbon resin; 25 g of modified carbon nanotubes and 9 g of fluorinated nanocellulose were mixed to obtain an additive; 10 g of N3390 and 5 g of Basonat HI-190 were mixed to obtain a second component;

[0062] S6. 99g of fluorocarbon resin, 0.30g of BYK-306, 0.64g of AFCONA-2722, 2g of BYK161, 1-3g of calcium carbonate, 0.7g of diamond titanium dioxide, 0.6g of additives and 2.7g of organic bentonite were added to the reactor, and then 20g of solvent was added, and the mixture was dispersed at a high speed of 900r / min for 28min, and ground three times with a horizontal grinder until the fineness was less than 30μm to obtain a first component;

[0063] S7. Mix 35 g of the first component and 3.4 g of the second component to obtain a fluorocarbon resin.

[0064] Embodiment 3: A method for preparing a high-solid nano-fluorocarbon primer, comprising the following steps:

[0065] S1. Add 220 mL of 70% concentrated nitric acid solution to 0.28 g of carbon nanotubes and boil for 38 min, then place under ultrasonic oscillation at 40 ° C for 4.5 h, centrifuge and precipitate repeatedly with deionized water until the solution becomes neutral, and dry at 91 ° C to obtain compound A;

[0066] S2. Add 120 mL of a mixed solution A of ethanol and water in a volume ratio of 9:1 to 5 g of heptadecafluorodecyltriethoxysilane, then add acetic acid dropwise to adjust the solution pH to 4, then add 10.3 g of compound A, and after ultrasonic dispersion for 38 min, stir at 60 ° C for 4.5 h, centrifuge, wash with deionized water, and dry at 68 ° C for 28 min to obtain compound B;

[0067] S3. Add 38 g of tetrahydrofuran to 15 g of compound B, mix well, then add 8 g of leveling agent BYK-306 and 4 g of polyamide wax, stir at 48 ° C for 3 h, filter, wash with ethanol aqueous solution, and dry at 62 ° C for 28 min to obtain modified carbon nanotubes;

[0068] S4. Add 9 g of nanocellulose to 30 g of dimethyl sulfoxide, stir evenly, place in a plasma reactor, use carbon tetrafluoride as plasma gas, and evacuate by vacuum pump until the initial vacuum degree is less than 3×10 -3 Pa, plasma treatment was carried out in a dielectric barrier discharge chamber, the plasma treatment time was set to 18 min, the power was 120 W, the gas flow rate of carbon tetrafluoride was 6 mL / min, and then washed with ethanol for 3 times, and dried at 58 ° C for 25 min to obtain fluorinated nanocellulose;

[0069] S5. 11 g of propylene glycol methyl ether acetate, 7 g of dipropylene glycol dimethyl ether and 3 g of butyl acetate were mixed to obtain a solvent; 1 g of HLR-6 and 2.5 g of HLR-670 were mixed to obtain a fluorocarbon resin; 28 g of modified carbon nanotubes and 11 g of fluorinated nanocellulose were mixed to obtain an additive; 12 g of N3390 and 6 g of Basonat HI-190 were mixed to obtain a second component;

[0070] S6. 104g of fluorocarbon resin, 0.32g of BYK-306, 0.68g of AFCONA-2722, 2.2g of BYK161, 2g of calcium carbonate, 0.8g of diamond titanium dioxide, 0.9g of additives and 2.9g of organic bentonite were added to the reactor, and then 22g of solvent was added, and the mixture was dispersed at a high speed of 900r / min for 32min, and ground three times with a horizontal grinder until the fineness was less than 30μm to obtain a first component;

[0071] S7. 37 g of the first component and 4 g of the second component are mixed to obtain a fluorocarbon resin.

[0072] Embodiment 4: A method for preparing a high-solid nano-fluorocarbon primer comprises the following steps:

[0073] S1. Add 230 mL of 70% concentrated nitric acid solution to 0.32 g of carbon nanotubes and boil for 40 min, then place under ultrasonic oscillation at 40 ° C for 5 h, centrifuge and precipitate repeatedly with deionized water until the solution becomes neutral, and dry at 95 ° C to obtain compound A;

[0074] S2. Add 125 mL of a mixed solution A of ethanol and water in a volume ratio of 9:1 to 5.5 g of heptafluorodecyltriethoxysilane, then add acetic acid dropwise to adjust the solution pH to 4, then add 10.6 g of compound A, and after ultrasonic dispersion for 40 min, stir at 62 ° C for 5 h, centrifuge, wash with deionized water, and dry at 70 ° C for 30 min to obtain compound B;

[0075] S3. 40 g of tetrahydrofuran was added to 16 g of compound B, mixed evenly, and then 9 g of leveling agent BYK-306 and 5 g of polyamide wax were added, stirred at 50 ° C for 3.5 h, filtered, washed with ethanol aqueous solution, and dried at 65 ° C for 30 min to obtain modified carbon nanotubes;

[0076] S4. Add 11 g of nanocellulose to 32 g of dimethyl sulfoxide, stir evenly, place in a plasma reactor, use carbon tetrafluoride as plasma gas, and evacuate by vacuum pump until the initial vacuum degree is less than 3×10 -3 Pa, plasma treatment was carried out in a dielectric barrier discharge chamber, the plasma treatment time was set to 20 min, the power was 125 W, the gas flow rate of carbon tetrafluoride was 7 mL / min, and then washed with ethanol for 3 times, and dried at 60 ° C for 25 min to obtain fluorinated nanocellulose;

[0077] S5. 12 g of propylene glycol methyl ether acetate, 8 g of dipropylene glycol dimethyl ether and 4 g of butyl acetate were mixed to obtain a solvent; 1 g of HLR-6 and 2.7 g of HLR-670 were mixed to obtain a fluorocarbon resin; 30 g of modified carbon nanotubes and 12 g of fluorinated nanocellulose were mixed to obtain an additive; 14 g of N3390 and 7 g of Basonat HI-190 were mixed to obtain a second component;

[0078] S6. 108g of fluorocarbon resin, 0.35g of BYK-306, 0.72g of AFCONA-2722, 2.5g of BYK161, 3g of calcium carbonate, 1g of diamond titanium dioxide, 1.2g of additives and 3g of organic bentonite were added to the reactor, and then 23g of solvent was added, and the mixture was dispersed at a high speed of 1000r / min for 35min, and ground three times with a horizontal grinder until the fineness was less than 30μm to obtain a first component;

[0079] S7. Mix 40 g of the first component and 4 g of the second component to obtain a fluorocarbon resin.

[0080] Comparative Example 1:

[0081] Compared with Example 1, the modified carbon nanotubes were not added in the preparation process of the high-solid nano-fluorocarbon primer in this comparative example. The remaining steps and parameters were the same and will not be repeated in this comparative example. Finally, a high-solid nano-fluorocarbon primer was obtained.

[0082] Comparative Example 2:

[0083] Compared with Example 1, this comparative example does not add fluorinated nano-cellulose during the preparation of the high-solid nano-fluorocarbon primer, and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high-solid nano-fluorocarbon primer is obtained.

[0084] Comparative Example 3:

[0085] Compared with Example 1, this comparative example only replaces "modified carbon nanotubes" with "carbon nanotubes", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high-solid nano fluorocarbon primer is obtained.

[0086] Comparative Example 4:

[0087] Compared with Example 1, this comparative example only replaces "fluorinated nanocellulose" with "nanocellulose", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high-solid nano fluorocarbon primer is obtained.

[0088] Comparative Example 5:

[0089] Compared with Example 1, this comparative example only replaces "12g propylene glycol methyl ether acetate, 8g dipropylene glycol dimethyl ether and 4g butyl acetate" with "24g butyl acetate", and the remaining steps and parameters are the same, which will not be repeated in this comparative example, and finally a high-solid nano fluorocarbon primer is obtained.

[0090] Performance Testing:

[0091] A tinplate with a specification of 150 mm × 70 mm × (0.2-0.3) mm was used as a substrate, which was polished with 400-mesh sandpaper before spraying, and then wiped clean with acetone. The high-solid nano-fluorocarbon primer prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was sprayed evenly on the substrate by an electrostatic spray gun, and dried in an oven at 105° C. ± 2° C. for 1 h. After drying, the sample was taken out and cooled to room temperature at room temperature to obtain 9 samples of Examples 1 to 4 and Comparative Examples 1 to 5, respectively;

[0092] Solid content: Referring to the GB / T 1725-2007 test standard, 1 g of the high-solid nano-fluorocarbon primer prepared in Examples 1 to 4 and Comparative Examples 1 to 5 was taken respectively, and sprayed evenly on the sample plate by an electrostatic spray gun, and dried in an oven at 105°C ± 2°C for 1 h. After drying, the sample was taken out, cooled to room temperature, and the mass of the dried sample was weighed using an electronic balance (m2);

[0093] Solid content calculation formula:

[0094]

[0095] Wherein, m1 is the mass of the sample before drying, and m2 is the mass of the sample after drying;

[0096] Tensile strength: refer to GB / T 258-2009 test standard to test the tensile strength of each group of samples;

[0097] Acid resistance: Referring to the GB / T 9274-88 test standard, immerse each group of samples in a 10% hydrochloric acid solution for 672 hours and a 10% sodium hydroxide solution for 672 hours, and observe whether there is any weight gain in each group of samples;

[0098] Salt spray resistance: refer to ISO7253 standard to test the salt spray resistance of each group of samples, and record the surface status of each group of samples after 800h of salt spray resistance test;

[0099] Impact resistance: Test the impact resistance of each group of samples according to GB / T1732-1993 standard;

[0100] Adhesion: Test the adhesion of each group of samples according to GB / T 9286-1998 standard;

[0101] Leveling: Test the leveling of each group of samples according to GB / T1727-79 standard;

[0102] Leveling evaluation criteria:

[0103] Good leveling property: the coating reaches a smooth surface within 10 minutes after spraying, with no obvious brush marks or orange peel, and good surface flatness;

[0104] Poor leveling: The coating has not reached a smooth surface after more than 10 minutes, and there are brush marks and orange peel on the surface, and the surface flatness is average;

[0105] Very poor leveling: The coating surface cannot be leveled, and there are a lot of brush marks, bubbles or accumulation.

[0106] Table 1

[0107]

[0108] Table 2

[0109]

[0110]

[0111] Data Analysis:

[0112] It can be seen from Table 1 and Table 2 that the high-solid nano-fluorocarbon primer prepared by the present invention has better leveling, adhesion and impact resistance and has a high solid content. This may be because in the present invention, the additive is composed of modified carbon nanotubes and fluorinated nanocellulose, wherein the carbon nanotubes in the modified carbon nanotubes are chemically modified by a fluorinated silane coupling agent. On the one hand, the surface of the modified carbon nanotubes contains a large number of active groups and has a high surface activity. It can react chemically and physically adsorb with the fluorine resin and pigment in the coating, thereby enhancing the adhesion between the coating and the substrate. On the other hand, the dispersibility of the carbon nanotubes in the coating is effectively improved, and the occurrence of agglomeration is avoided. , thereby improving the overall leveling of the coating; in electrostatic spraying, due to the conductivity of carbon nanotubes, the loaded leveling agent BYK-306 can better exert the leveling effect, and the polyamide wax contains a variety of active groups, which can better utilize the intermolecular hydrogen bonds in the modified carbon nanotubes to form a network structure to prevent the occurrence of inverted hanging phenomenon. The amide groups have a strong adsorption affinity for metal ions, that is, the fluorocarbon primer has good adhesion to the metal substrate; and, on the one hand, the surface of fluorinated nanocellulose will have a slight change in roughness, which is conducive to improving the spreading ability of the paint film and avoiding the occurrence of sagging phenomenon; on the other hand, the -CF introduced on its surface 3The group can reduce the surface energy and enhance the compatibility with the fluorocarbon resin, and the overall leveling property of the fluorocarbon primer is further improved; moreover, the solvent in the present invention is composed of three solvents with different volatilization rates, namely, fast volatilization, medium volatilization and slow volatilization. The three play a synergistic role, making the entire coating surface smoother and flatter, reducing leveling defects such as orange peel and shrinkage cavities, and generating a certain shrinkage stress during the volatilization process, thereby improving the adhesion to the substrate.

[0113] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present invention is limited to these examples. Under the concept of the present invention, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the present invention as described above, which are not provided in detail for the sake of simplicity.

[0114] The present invention is intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high solid nano fluorocarbon primer, characterized in that: Including the following raw materials by weight: The first component is 32-40g; the second component is 3-4g; The first component is prepared from the following raw materials in parts by weight: Fluorocarbon resin 95-108g; leveling agent 0.28-0.35g; defoamer 0.6-0.72g; dispersant 1.8-2.5g; filler 1-3g; pigment 0.5-1g; thixotropic agent 2.6-3g; additive 0.3-1.2g; solvent 18-23g; The second component is an aliphatic isocyanate polymer; The aliphatic isocyanate polymer is obtained by mixing N3390 and Basonat HI-190 in a mass ratio of 8-14:4-7; The fluorocarbon resin is obtained by mixing HLR-6 and HLR-670 in a mass ratio of 1:2-2.7; The auxiliary agent is obtained by mixing modified carbon nanotubes and fluorinated nanocellulose in a mass ratio of 23-30:7-12; The modified carbon nanotubes are prepared from carbon nanotubes, heptadecafluorodecyltriethoxysilane, BYK-306 and polyamide wax; The solvent is obtained by mixing propylene glycol methyl ether acetate, dipropylene glycol dimethyl ether and butyl acetate in a mass ratio of 8-12:5-8:2-4.

2. The high solid nano fluorocarbon primer according to claim 1, characterized in that: The preparation method of the modified carbon nanotubes is as follows: S1. Add a 70% concentrated nitric acid solution to the carbon nanotubes and boil for 30-40 minutes, place at 40°C for 4-5 hours under ultrasonic vibration, and then repeatedly centrifuge and precipitate with deionized water until the solution becomes neutral, and then dry to obtain compound A; S2. Add ethanol and water in a volume ratio of 9:1 to heptadecafluorodecyltriethoxysilane in a mixed solution A, then add acetic acid dropwise to adjust the solution pH to 3-4, then add compound A, ultrasonically disperse for 30-40 min, stir at 55-62 ° C for 4-5 h, then centrifuge, wash with deionized water, and dry to obtain compound B; S3. Add tetrahydrofuran to compound B, mix well, then add leveling agent BYK-306 and polyamide wax, stir at 40-50° C. for 2.5-3.5 hours, filter, wash with ethanol aqueous solution, and dry to obtain modified carbon nanotubes.

3. The high solid nano fluorocarbon primer according to claim 2, characterized in that: The carbon nanotubes and concentrated nitric acid solution in S1 are used in a ratio of 0.2-0.32 g: 180-230 mL; The temperature during the drying is 85-95° C. and the time is 25-30 minutes.

4. The high solid nano fluorocarbon primer according to claim 2, characterized in that: The usage ratio of heptadecafluorodecyltriethoxysilane, mixed solution A and compound A in S2 is 4.5-5.5 g:110-125 mL:9.8-10.6 g; The drying temperature is 60-70°C and the drying time is 25-30 minutes.

5. The high solid nano fluorocarbon primer according to claim 2, characterized in that: The mass ratio of compound B, tetrahydrofuran, leveling agent BYK-306 and polyamide wax in S3 is 12-16; 30-40: 6-9: 2-5; The drying temperature is 55-65° C. and the drying time is 35-40 minutes.

6. The high solid nano fluorocarbon primer according to claim 1, characterized in that: The preparation method of the fluorinated nanocellulose is as follows: Nanocellulose was added to dimethyl sulfoxide, stirred evenly, and placed in a plasma reactor. Carbon tetrafluoride was used as the plasma gas, and the plasma was evacuated by a vacuum pump until the initial vacuum degree was less than 3×10 -3 Pa, plasma treatment is carried out in a dielectric barrier discharge chamber, and then washed with ethanol 2-3 times and dried to obtain fluorinated nanocellulose.

7. The high solid nano fluorocarbon primer according to claim 6, characterized in that: The mass ratio of dimethyl sulfoxide to nanocellulose is 25-32:5-11; The plasma treatment time is 15-20 minutes, the power is 110-125W, and the gas flow rate of carbon tetrafluoride is 4-7mL / min; The drying temperature is 50-60°C and the drying time is 20-25 minutes.

8. The high solid nano fluorocarbon primer according to claim 1, characterized in that: The leveling agent is BYK-306; The defoamer is AFCONA-2722; The filler is any one of calcium carbonate and white carbon black.

9. The high solid nano fluorocarbon primer according to claim 1, characterized in that: The dispersant is any one of BASF4401 and BYK161; The pigment is diamond titanium dioxide; The thixotropic agent is organic bentonite.

10. The high solid nano fluorocarbon primer according to claim 1, characterized in that: The preparation method of the first component comprises the following steps: Add fluorocarbon resin, leveling agent, defoamer, dispersant, filler, pigment, additive and thixotropic agent into a reaction kettle respectively, then add solvent, disperse at high speed until uniform, grind with a horizontal grinder 2-3 times until the fineness is less than 30 μm, to obtain a first component; mix the first component and the second component to obtain a fluorocarbon resin; The speed of the high-speed dispersion is 800-1000 r / min, and the stirring time is 25-35 min.

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