Vinyl modified fluorocarbon resin, preparation method thereof, and corrosion-resistant coating and preparation method and application thereof

[0034] The invention provides a method for preparing a vinyl-modified fluorocarbon resin, which includes the following steps: mixing a vinyl monomer containing a fluorine group, an initiator, and a tetrafluoroethylene gas phase monomer, and performing an addition reaction to obtain ethylene Based modified fluorocarbon resin.

[0035] The present invention does not specifically limit the preparation method of the perfluoro group-containing fluorocarbon monomer, as long as the preparation method well known to those skilled in the art can be used. In the present invention, the vinyl group containing the fluorine group The preparation method of the monomer preferably includes the following steps:

[0036] (1) Mixing perfluorooctanoic acid, thionyl chloride and N,N-dimethylformamide to perform the first esterification reaction to obtain perfluorooctanoyl chloride;

[0037] (2) Mixing the perfluorooctanoyl chloride, ethanolamine, and tetrahydrofuran to perform a second esterification reaction to obtain N-hydroxyethyl perfluorooctanoamide;

[0038] (3) Mix the N-hydroxyethyl perfluorooctylamide, 2,4-toluene diisocyanate, methyl isobutyl ketone, dibutyltin dilaurate and β-hydroxyethyl methacrylate to perform a synthesis reaction , To obtain a vinyl monomer containing a fluorine group.

[0039] In the present invention, it is preferable to mix perfluorooctanoic acid, thionyl chloride and N,N-dimethylformamide to perform the first esterification reaction to obtain perfluorooctanoyl chloride. In the present invention, the mass ratio of the perfluorooctanoic acid, thionyl chloride and N,N-dimethylformamide is preferably 15:9:3 to 5, more preferably 15:9:3. In the present invention, the temperature of the first esterification reaction is preferably 70-100°C, more preferably 85°C; the time of the first esterification reaction is preferably 50-70 min, more preferably 1 h. In the present invention, after the first esterification reaction is completed, the obtained system is preferably subjected to reduced pressure distillation to remove excess thionyl chloride, and fractions at 60-72° C. are collected at 1.07 kPa to obtain perfluorooctanoyl chloride. In the present invention, the perfluorooctanoyl chloride is a white transparent liquid with a strong pungent odor, and the yield is greater than 92%.

[0040] After obtaining the perfluorooctanoyl chloride, the present invention preferably mixes the perfluorooctanoyl chloride with ethanolamine and tetrahydrofuran to perform the second esterification reaction to obtain N-hydroxyethyl perfluorooctanoyl amide. In the present invention, the dosage ratio of the perfluorooctanoyl chloride, ethanolamine and tetrahydrofuran is preferably 8-10 g: 2-3 g: 9-12 mL, more preferably 8.5 g: 2.5 g: 10 mL. In the present invention, the specific method of mixing is preferably: first mixing ethanolamine and tetrahydrofuran (THF), cooling in an ice salt bath to below 5°C, and slowly adding the perfluorooctanoyl chloride dropwise with stirring.

[0041] In the present invention, the temperature of the second esterification reaction is preferably 30 to 40°C, more preferably 30°C; the time of the second esterification reaction is preferably 2 to 4 hours, more preferably 3 hours. In the present invention, after the completion of the second esterification reaction, the obtained system is preferably distilled under reduced pressure to remove THF, and then 10 mL of hot water at 70°C is added for washing and liquid separation while hot; dilute hydrochloric acid is used to adjust the pH of the paste It is 7.5-8.0, then washed with hot water once, and the product is recrystallized twice with chloroform to obtain N-hydroxyethyl perfluorooctamide. In the present invention, the N-hydroxyethyl perfluorooctamide is light yellow crystals, the melting point is 51-52°C, and the yield is greater than 77%.

[0042] After obtaining N-hydroxyethyl perfluorooctylamide, the present invention preferably mixes said N-hydroxyethyl perfluorooctylamide, 2,4-toluene diisocyanate, methyl isobutyl ketone and dibutyltin dilaurate to carry out Synthetic reaction to obtain fluorocarbon monomer containing perfluoro group. In the present invention, the dosage ratio of the N-hydroxyethyl perfluorooctamide, 2,4-toluene diisocyanate, methyl isobutyl ketone, and β-hydroxyethyl methacrylate is preferably 4.2-4.8 g: 1.5 to 1.8 g: 3 to 6 mL: 1.1 to 1.9 g, more preferably 4.57 g: 1.74 g: 4 mL: 1.6 g. In the present invention, the specific method of mixing is preferably: first mixing 2,4-toluene diisocyanate (TDI), methyl isobutyl ketone (MIBK) and 1 drop of dibutyl tin dilaurate, and then under nitrogen atmosphere , The temperature is raised to 65~70℃, and 4.57g of the N-hydroxyethyl perfluorooctanoic acid amine and 12mL of anhydrous MIBK are slowly added dropwise in sequence. The dropping time is 1h. After the dropping, keep this temperature to react for 3h, then add 2 more drops Dibutyltin dilaurate, after heating to 75-80°C, slowly drop 1.6 g of β-hydroxyethyl methacrylate.

[0043] In the present invention, the temperature of the synthesis reaction is preferably 75-80°C, more preferably 75°C; the time of the synthesis reaction is preferably 3-6h, more preferably 4h. In the present invention, preferably after the synthesis reaction is completed, the obtained system is subjected to reduced pressure distillation to remove MIBK, and recrystallized with THF to obtain a fluorocarbon monomer containing a perfluoro group. In the present invention, the vinyl monomer containing a fluorine group is light brown transparent crystal, and the yield is greater than 81%.

[0044] In the present invention, the structural formula of the vinyl monomer containing a fluorine group is shown in figure 1 in:

[0045] In the present invention, the initiator is preferably maleic anhydride (MA).

[0046] In the present invention, the structural formula of the tetrafluoroethylene gas phase monomer is: C 2 F 4.

[0047] In the present invention, the mass ratio of the fluorine group-containing vinyl monomer, initiator and tetrafluoroethylene monomer is preferably 15:9:3.

[0048] In the present invention, the specific method for mixing the fluorine-containing vinyl monomer, initiator and tetrafluoroethylene gas phase monomer is preferably: firstly mixing the fluorine-containing vinyl monomer and the initiator to obtain The liquid is mixed, and then nitrogen containing tetrafluoroethylene gas phase monomer is passed into the mixed liquid. In the present invention, the effective content of tetrafluoroethylene in the tetrafluoroethylene gas phase monomer is less than 2×10 -5 g/L.

[0049] In the present invention, the addition reaction is preferably carried out under stirring conditions, and the stirring speed is preferably 2000-2500 r/min; the temperature of the addition reaction is preferably 75-80°C, more preferably 76°C; The time of the addition reaction is preferably 18-22 h, more preferably 20 h. In the present invention, during the addition reaction process, the vinyl group is grafted with tetrafluoroethylene.

[0050] In the present invention, after the addition reaction is completed, the obtained system is preferably cooled, then vacuumed, and replaced with nitrogen to obtain a vinyl-modified fluorocarbon resin. In the present invention, the cooling rate is preferably 1°C/min, and the temperature of the system after cooling is preferably 25°C. The role of nitrogen replacement in the present invention is to prevent the generation of by-products.

[0051] The vinyl-modified fluorocarbon resin prepared by the present invention has figure 2 The molecular structure shown, the specific reaction equation is image 3 The vinyl-modified fluorocarbon resin contains hydroxyl, carboxyl and fluorine-containing side chains. Among them, hydroxyl can improve crosslinking and adhesion, carboxyl can improve pigment crosslinking adhesion, and fluorine-containing side chains can improve weather resistance and resistance. Acidity, hardness and gloss.

[0052] by figure 2 The analysis shows that the vinyl-modified fluorocarbon resin provided by the present invention is used to prepare corrosion-resistant coatings, and the groups in the vinyl-modified fluorocarbon resin can be used to improve the dispersibility and adhesion of the pigment and improve the cross-linking between the components. , Improve the flexibility of the resin, improve the solubility of the resin, improve the transparency, gloss and hardness of the paint film, and improve the weather resistance of the paint film.

[0053] The present invention provides a corrosion-resistant coating, including separately packaged A component and B component;

[0054] In parts by weight, the raw materials for the preparation of component A include: 50 to 70 parts of vinyl-modified fluorocarbon resin, 3 to 8 parts of fillers, 2 to 5 parts of zinc phosphate, and graphene dispersion as described in the above technical scheme 2~5 parts of paste, 5~20 parts of pigment, 0.2~1 part of dispersant, 0.1~0.3 part of defoaming agent, 0.1~0.3 part of leveling agent, 1-3 part of polyamide wax slurry, 0.2~ of fumed silica 0.5 part and 9-16 parts of organic solvent; the solid content of the graphene dispersion slurry is 2-10%; the solid content of the polyamide wax slurry is 10-20%; the component B is isocyanate; The mass ratio of the A component and the B component is 100:10-30, preferably 100:20.

[0055] In the present invention, in terms of parts by weight, the raw materials for the preparation of the A component include 50 to 70 parts of the vinyl-modified fluorocarbon resin described in the above technical scheme, and specifically preferably 50 parts, 60 parts or 70 parts. In the present invention, the preparation method and structural formula of the vinyl-modified fluorocarbon resin are as described above and will not be repeated here. The vinyl-modified fluorocarbon resin has excellent strong acid resistance and strong alkali resistance. At the same time, it has excellent weather resistance and can improve the acid and alkali resistance of the coating.

[0056] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 3-8 parts of fillers, and specifically preferably 3 parts, 4 parts or 8 parts. In the present invention, the filler is preferably nano barium sulfate, and the particle size of the nano barium sulfate is preferably 5-10 nm, more preferably 5 nm. In the embodiment of the present invention, the source of the nano barium sulfate is preferably Changhe Chemical. In the present invention, the nano barium sulfate has the advantages of strong chemical inertness, good stability, acid and alkali resistance, moderate hardness, high specific gravity, high whiteness, and ability to absorb harmful rays, and can improve the strong acid and strong resistance of corrosion-resistant coatings. Alkaline.

[0057] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw material for the preparation of the A component includes 2 to 5 parts of zinc phosphate, and specifically preferably 2, 3 or 5 parts. In the embodiment of the present invention, the source of the zinc phosphate is preferably Huanqi Chemical PZ20. In the present invention, the zinc phosphate can improve the salt spray resistance of the paint film.

[0058] In the present invention, based on the weight parts of the vinyl-modified fluorocarbon resin, the raw material for the preparation of the A component includes 2 to 5 parts of graphene dispersion slurry, and specifically preferably 2 parts, 3 parts or 5 parts. Parts; the solid content of the graphene dispersion slurry is 2-10%, preferably 10%. In the present invention, the source of the graphene dispersion slurry is preferably Jiangsu Gaotong New Material. In the present invention, the graphene dispersion slurry can improve the chemical resistance and salt spray resistance of the paint film.

[0059] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 5-20 parts of pigments, specifically 5 parts, 11 parts or 20 parts. In the present invention, the pigment is preferably an inorganic pigment, and specifically it is preferably rutile-type titanium dioxide and iron oxide black. In the present invention, the source of the pigment is preferably Hangzhou Xinlux. In the present invention, the pigment can not only improve the aesthetics of the paint film but also improve the media resistance of the paint film.

[0060] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw material for the preparation of the A component includes 0.2 to 1 part of the dispersant, and specifically preferably 0.2 part, 0.5 part or 1 part. In the present invention, the effective component of the dispersant is preferably a high molecular weight block copolymer; the source of the dispersant is preferably BYK163. In the present invention, the dispersant can disperse the pigments and fillers in the system to prevent aggregation and precipitation.

[0061] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 0.1-0.3 parts of defoaming agent, specifically preferably 0.1 part, 0.2 part or 0.3 part . In the present invention, the effective component of the antifoaming agent is preferably modified polysiloxane; the source of the antifoaming agent is preferably Hemmings 5800F. In the present invention, the defoaming agent can avoid bubbles in the paint film.

[0062] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 0.1-0.3 parts of a leveling agent, specifically preferably 0.1 parts, 0.2 parts or 0.3 parts . In the present invention, the effective component of the leveling agent is preferably modified polysiloxane; the source of the leveling agent is preferably Huizhengxing 466. In the present invention, the leveling agent can promote Liu Ping during the construction of the corrosion-resistant coating and improve the flatness of the paint film.

[0063] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 1 to 3 parts of polyamide wax slurry, specifically preferably 1 part, 2 parts or 3 parts. Copies. In the present invention, the source of the polyamide wax slurry is preferably Tisbalon 6900-20. In the present invention, the solid content of the polyamide wax slurry is 10-20%, preferably 20%. In the present invention, the polyamide wax slurry can improve the anti-settling and anti-sagging properties of the corrosion-resistant coating.

[0064] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw material for the preparation of the A component includes 0.2 to 0.5 parts of fumed silica, specifically preferably 0.2 parts, 0.3 parts or 0.5 parts. Copies. In the present invention, the source of the fumed silica is preferably Shanghai Haiyi N20. In the present invention, the fumed silica can improve the anti-settling property of the coating.

[0065] In the present invention, based on the parts by weight of the vinyl-modified fluorocarbon resin, the raw materials for the preparation of the A component include 9-16 parts of an organic solvent, and specifically preferably 9.2 parts, 9.7 parts or 15.2 parts. In the present invention, the organic solvent preferably includes a mixture of benzene solvents, ester solvents, hydrocarbon solvents, ketone solvents, and ether solvents. The benzene solvents, ester solvents, hydrocarbon solvents, and ketone solvents The volume ratio with the ether solvent is preferably 3 to 4:3 to 4:1 to 2:1 to 2:1 to 2, and more preferably 3:4:1:1:1. In the present invention, the benzene solvent is specifically xylene; the ester solvent is specifically anhydrous butyl acetate; the hydrocarbon solvent is specifically preferably hexane; the ketone solvent is specifically methane Butyl ethyl ketone; the ether solvent is specifically preferably ethylene glycol monobutyl ether. The invention adopts a mixed solvent for diluting other components in the coating and improving the uniformity of mixing of the components.

[0066] In the present invention, the B component is isocyanate, and the source of the isocyanate is preferably HI100. In the invention, the isocyanate is used as a curing agent to cause a crosslinking and curing reaction with the vinyl-modified fluorocarbon resin in the A component, thereby increasing the drying speed in the coating construction process.

[0067] The present invention also provides a preparation method of the corrosion-resistant coating described in the above technical scheme, including the preparation method of component A, and the preparation method of component A includes the following steps:

[0068] (1) The vinyl-modified fluorocarbon resin, dispersant, defoamer, polyamide wax slurry and part of the organic solvent are first mixed to obtain the first slurry;

[0069] (2) Perform a second mixing of the first slurry, pigment, zinc phosphate, filler and fumed silica to obtain a second slurry;

[0070] (3) Perform a third mixing of the second slurry and the graphene dispersion slurry to obtain a third slurry;

[0071] (4) The third slurry, the leveling agent and the remaining organic solvent are mixed fourthly to obtain component A.

[0072] In the present invention, the vinyl-modified fluorocarbon resin, dispersant, defoamer, polyamide wax slurry and part of organic solvent are first mixed to obtain the first slurry. In the present invention, the part of the organic solvent preferably accounts for 50-70% of the total weight of the organic solvent, more preferably 60%. In the present invention, the first mixing is preferably carried out under the first stirring condition, the speed of the first stirring is preferably 600-800r/min, more preferably 600r/min; the time is preferably 3-5min, more preferably For 4min.

[0073] After the first slurry is obtained, the present invention performs a second mixing of the first slurry, pigment, zinc phosphate, filler and fumed silica to obtain a second slurry. In the present invention, the second mixing preferably includes sequential second stirring and grinding, and the speed of the second stirring is preferably 800 to 1000 r/min, more preferably 800 r/min; the time of the second stirring It is preferably 15 to 20 minutes, more preferably 15 minutes. The present invention does not specifically limit the grinding method, and it is better to obtain a second slurry that meets the fineness requirements. The fineness of the second slurry is preferably 20-30 μm, more preferably 20 μm. The invention can improve the flatness of the paint film by grinding.

[0074] After the second slurry is obtained, in the present invention, the second slurry and the graphene dispersion slurry are subjected to a third mixing to obtain a third slurry. In the present invention, the third mixing is preferably carried out under the third stirring condition, the speed of the third stirring is preferably 1000-1200r/min, more preferably 1000r/min; the time is preferably 15-20min, more preferably For 15min.

[0075] After the third slurry is obtained, in the present invention, the third slurry, the leveling agent, and the remaining organic solvent are mixed for the fourth time to obtain component A. In the present invention, the fourth mixing is preferably carried out under the fourth stirring condition, and the speed of the fourth stirring is preferably 800-1000 r/min, more preferably 800 r/min; the fourth stirring time is preferably 5 to 10 minutes, more preferably 5 minutes.

[0076] The present invention adopts a step-by-step mixing method to prepare component A, which can make the components uniformly dispersed in the system and achieve more excellent performance.

[0077] In the present invention, the corrosion-resistant coating is preferably prepared and used immediately, and the A-component and the B-component are mixed during use to obtain the corrosion-resistant coating. In the present invention, the mixing is preferably carried out under stirring conditions, the stirring speed is preferably 200 r/min, and the time is preferably 5 min.

[0078] The present invention also provides the application of the corrosion-resistant coating of the above technical solution or the corrosion-resistant coating prepared by the preparation method of the above technical solution in the protection of metal surfaces. Preferably, the corrosion-resistant coating is applied to petroleum and petrochemical pipelines, chemical In the surface protection of transportation vehicles, steel structures of chemical enterprises, corrosion of chemical equipment, gas tanks, coal mine machinery and equipment, marine ships or warships. In the present invention, the corrosion-resistant coating is preferably used by spraying or roller coating. When spraying is used, the spraying amount is preferably 3.5-4kg/m 2.

[0080] Example 1

[0081] The raw materials and manufacturers are:

[0082] Perfluorooctanoic acid Shanghai Sanaifu New Material Co., Ltd.;

[0083] Thionyl Chloride Nanjing Rundi Industrial Co., Ltd.;

[0084] Β-hydroxyethyl methacrylate, 2,4-toluene diisocyanate, methyl methacrylate, ethyl acrylate and butyl acrylate, industrial grade, all manufactured by Miki Chemical Co., Ltd.;

[0085] Ethanolamine, dibutyltin dilaurate, N,N-dimethylformamide, methyl isobutyl ketone, chloroform, ethanol, acetone, NaOH, vinyl acid monomer and azobisisobutyronitrile, analytically pure, from Chengdu Branch Produced by Long Chemical Co., Ltd.

[0086] Add 15g of perfluorooctanoic acid and 9g of thionyl chloride into a four-necked flask equipped with a thermometer, agitator and reflux condenser, add 0.1g of N,N-dimethylformamide as a catalyst, and carry out the esterification reaction at 85℃ 1h, gas chromatograph analysis, reach the end when a plateau value appears; reduce excess thionyl chloride by distillation under reduced pressure, collect the fraction at 60~72℃ at 1.07kPa to obtain perfluorooctanoyl chloride, the obtained perfluorooctanoyl chloride is white Transparent liquid with strong pungent odor, the yield is greater than 92%;

[0087] Weigh 2.5g ethanolamine and 10mLTHF into a four-necked flask, cool to below 5°C in an ice-salt bath, slowly add 8.5g perfluorooctanoyl chloride dropwise with stirring, after the addition, heat to 30°C and continue the esterification reaction for 3h to obtain yellow Paste, gas chromatographic analysis has reached the end; vacuum distillation to remove THF, then add 10mL, 70 ℃ hot water to wash and separate the liquid while hot; use dilute hydrochloric acid (concentration 0.1g/mL) to adjust its pH 7.5 to 8.0, then wash with hot water once, the product is recrystallized twice with chloroform to obtain N-hydroxyethyl perfluorooctylamide, the obtained N-hydroxyethyl perfluorooctylamide is light yellow crystals, the melting point is 51-52 ℃, the yield is greater than 77%;

[0088] In a four-necked flask, add 1.74g TDI, 4mL anhydrous MIBK and 1 drop of dibutyltin dilaurate, protect with dry nitrogen, increase the temperature to 66°C, and slowly add 4.57g N-hydroxyethyl perfluorooctanoic acid amine and 12mL For water-treated MIBK, the total dripping time is 1h. After dripping, keep at this temperature and react for 3h, then add 2 drops of dibutyltin dilaurate, heat up to 79℃ and slowly add 1.6g of β-hydroxyethyl methacrylate. , And maintain this temperature for the synthesis reaction for 4h, and the gas chromatography analysis has reached the end; MIBK is removed by vacuum distillation, and recrystallized with THF to obtain the vinyl monomer with fluorine group, and the vinyl monomer with fluorine group is obtained. It is light brown transparent crystal with a yield greater than 81%.

[0089] Add 150g of vinyl monomer containing fluorine group and 90g of initiator into a reactor with stirring and electric heating, and vacuumize to oxygen 2 content <2×10 -5 g/L, add 30g of tetrafluoroethylene gas phase monomer into the reaction kettle at one time, raise the temperature to 75°C, and react for 20h under stirring conditions. After the reaction is over, cool the system (cooling rate is 1°C/min) to 25°C, It is evacuated into a vacuum, replaced with nitrogen, and discharged to obtain a vinyl modified fluorocarbon resin.

[0090] Example 2

[0091] The preparation method of the fluorine-containing vinyl monomer is the same as in Example 1;

[0092] Add 300g of vinyl monomer containing fluorine groups and 180g of initiator into the reactor with stirring and electric heating, and vacuumize to oxygen 2 content <2×10 -5 g/L, add 60g tetrafluoroethylene gas phase monomer into the reaction kettle at one time, raise the temperature to 76°C, react for 20h under stirring conditions, after the reaction, cool the system (cooling rate is 1°C/min) to 25°C, It is evacuated into a vacuum, replaced with nitrogen, and discharged to obtain a vinyl modified fluorocarbon resin.