A kind of anticorrosive Teflon coating and its preparation method and application

Abstract

The present invention provides an anti-corrosion Teflon coating, its preparation method, and application, belonging to the technical field of coatings. Polytetrafluoroethylene micropowder is irradiated and then grafted with glycidyl methacrylate. The resulting powder is then reacted with graphene modified with phosphorus oxychloride and polydopamine, added to a Teflon primer, and stirred to produce the anti-corrosion Teflon coating. The anti-corrosion Teflon coating exhibits excellent high-temperature resistance, corrosion resistance, rust resistance, mechanical properties, wear resistance, scratch resistance, and media resistance. It effectively resists high-wear environments such as sliding friction, impact friction, and cavitation friction, as well as highly corrosive environments such as acidic and alkaline media, and has broad application prospects.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to an anti-corrosion Teflon coating and a preparation method and application thereof. Background Art

[0002] Teflon coating is an industrial coating with polytetrafluoroethylene (PTFE) as its main component. It has many excellent properties, such as non-stickiness, heat resistance, sliding, moisture resistance, wear resistance, and corrosion resistance, which makes it widely used in many industries.

[0003] In recent years, the research on anti-corrosion coatings has been very rapid. Based on the traditional conventional anti-corrosion coatings, many varieties with excellent performance have been developed. Among them, the commonly used anti-corrosion coating is epoxy zinc-rich coating. Epoxy zinc-rich coating is a heavy-duty anti-corrosion coating with excellent corrosion resistance and is widely used in the field of heavy-duty metal corrosion protection. Zinc in epoxy zinc-rich coating is a sacrificial anode, and its content in the coating is usually greater than 70%. However, due to the high zinc powder content in the coating, the coating tends to be porous and the adhesion is reduced. In addition, the zinc-rich coating produces more zinc salts when it plays a cathodic protection role, which affects the bonding strength between the upper coating and the zinc-rich coating, thereby reducing the anti-corrosion performance of the coating. Summary of the Invention

[0004] The purpose of the present invention is to propose an anti-corrosion Teflon coating and its preparation method and application, which has good high temperature resistance, corrosion resistance, rust resistance, mechanical properties, wear resistance, scratch resistance, medium resistance and other properties, can effectively resist high wear-resistant environments such as sliding friction, impact friction, cavitation friction, as well as high corrosion environments such as acidic media and alkaline media, and has broad application prospects.

[0005] The technical solution of the present invention is achieved as follows:

[0006] 1. The present invention provides a method for preparing an anti-corrosion Teflon coating, characterized in that it comprises the following steps:

[0007] S1. Polytetrafluoroethylene powder was added to Augeo SL-191 solvent. Under irradiation conditions, glycidyl methacrylate, a polymerization inhibitor, and a sensitizer were added. An inert gas was introduced and the reaction was heated with stirring. After the reaction, the mixture was extracted with acetone and dried to obtain a modified Teflon powder. The mass ratio of the polytetrafluoroethylene powder, glycidyl methacrylate, polymerization inhibitor, and sensitizer was 10:2-3:0.01-0.02:0.02-0.05.

[0008] S2. Graphene oxide was added to water, dopamine hydrochloride and a catalyst were added, the reaction was heated with stirring, filtered, washed, and dried to obtain modified graphene oxide; the mass ratio of the graphene oxide, dopamine hydrochloride and the catalyst was 10:3-4:0.5-1;

[0009] S3. The modified graphene oxide is reduced with hydrazine hydrate vapor to obtain modified graphene;

[0010] S4 phosphorus oxychloride and modified graphene were added to a solvent, the reaction was heated with stirring, centrifuged, washed, and dried to obtain a composite; the mass ratio of phosphorus oxychloride, modified graphene was 3-4:10;

[0011] S5. The modified Teflon powder and the compound are added to the Teflon primer, stirred and reacted to obtain an anti-corrosion Teflon coating; the mass ratio of the modified Teflon powder, the compound, and the Teflon primer is 10:3-5:75-85.

[0012] As a further improvement of the present invention, the temperature of the irradiation conditions in step S1 is 100-150°C, the total irradiation dose is 12-15 kGy, the inhibitor is ammonium ferrous sulfate, the sensitizer is concentrated sulfuric acid, the temperature of the heating and stirring reaction is 60-70°C, and the heating and stirring reaction time is 3-5 hours.

[0013] As a further improvement of the present invention, the catalyst in step S2 is a Tris-HCl solution with a pH of 9-10, the temperature of the heating and stirring reaction is 45-55° C., and the time of the heating and stirring reaction is 1-3 hours.

[0014] As a further improvement of the present invention, the reduction time in step S3 is 7-10 hours.

[0015] As a further improvement of the present invention, the solvent in step S4 is selected from at least one of ethyl acetate, dichloromethane, acetone, tetrahydrofuran, and N,N-dimethylformamide, the temperature of the heating and stirring reaction is 75-85° C., and the time of the heating and stirring reaction is 2-4 hours.

[0016] As a further improvement of the present invention, the stirring reaction time in step S5 is 7-10 hours.

[0017] As a further improvement of the present invention, the present invention specifically comprises the following steps:

[0018] S1. 10 parts by weight of polytetrafluoroethylene powder was added to Augeo SL-191 solvent and irradiated at 100-150°C for a total irradiation dose of 12-15 kGy. Then, 2-3 parts by weight of glycidyl methacrylate, 0.01-0.02 parts by weight of ammonium ferrous sulfate, and 0.02-0.05 g of concentrated sulfuric acid were added. Nitrogen was introduced and the mixture was heated to 60-70°C with stirring for 3-5 hours. After the reaction, the mixture was extracted with acetone for 24 hours and dried to obtain modified Teflon powder.

[0019] S2. Add 10 parts by weight of graphene oxide to water, add 3-4 parts by weight of dopamine hydrochloride and 0.5-1 parts by weight of a catalyst, heat to 45-55°C, stir and react for 1-3 hours, filter, wash, and dry to obtain modified graphene oxide;

[0020] The catalyst is a Tris-HCl solution with a pH of 9-10;

[0021] S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 7-10h to obtain modified graphene;

[0022] S4. 3-4 parts by weight of phosphorus oxychloride and 10 parts by weight of modified graphene were added to a solvent, heated to 75-85 ° C, stirred for 2-4h, centrifuged, washed, and dried to obtain a composite;

[0023] S5. Add 10 parts by weight of modified Teflon powder and 3-5 parts by weight of the compound to 75-85 parts by weight of Teflon primer, and stir the reaction for 7-10 hours to obtain an anti-corrosion Teflon coating.

[0024] The present invention further protects an anti-corrosion Teflon coating, which is prepared by the above-mentioned preparation method.

[0025] The present invention further protects a use of the above-mentioned anti-corrosion Teflon coating in preparing kitchenware coatings.

[0026] The present invention has the following beneficial effects:

[0027] The invention uses electron beam or gamma ray irradiation to break C—C bonds and C—F bonds on the Teflon polytetrafluoroethylene chain to generate free radicals, and utilizes these free radicals to initiate a grafting reaction of glycidyl methacrylate monomer on the surface of the Teflon polytetrafluoroethylene, thereby improving the polarity of the PTFE and further increasing its compatibility and reactivity with other substances. The grafted modified Teflon powder can undergo a ring-opening reaction with the modified graphite powder having amino groups on the surface, so that the modified graphite powder can be very evenly dispersed in the Teflon coating, thereby improving the compatibility of the inorganic particles and greatly improving the mechanical properties, wear resistance, rust resistance, medium resistance and other characteristics of the coating.

[0028] The Augeo SL-191 used in the present invention is a new, environmentally friendly solvent developed by Rhodia that is both hydrophilic and lipophilic. It has a high boiling point, is colorless and odorless, has a low volatilization rate, and is non-toxic to human health and the environment.

[0029] The present invention modifies the surface of graphene oxide with polydopamine so that the surface of the graphene oxide has rich amino groups. At the same time, the modified graphene is obtained after reduction with hydrazine hydrate vapor. After the modified graphene is added to a Teflon primer, the pores of the coating become smaller, the anti-corrosion performance is enhanced, and the mechanical properties and wear resistance are significantly improved. Introducing the modified graphene into the coating improves the comprehensive performance of the coating.

[0030] The present invention then uses modified graphene to react with phosphorus oxychloride to prepare a composite, and the chlorine atoms undergo a nucleophilic substitution reaction with the amino groups, so that the phosphorus oxychloride is grafted on the surface of the modified graphene. On the one hand, the high-temperature resistance of the coating is improved. At the same time, the phosphorus element can also form a complex with the metal ions to obtain a solid protective layer. This dense passivation layer is insoluble in water, has high hardness, and has excellent anti-corrosion and anti-rust effects.

[0031] The anti-corrosion Teflon coating prepared by the present invention has good high temperature resistance, corrosion resistance, rust resistance, mechanical properties, wear resistance, scratch resistance, medium resistance and other properties. It can effectively resist high wear-resistant environments such as sliding friction, impact friction, cavitation friction, as well as high corrosion environments such as acidic media and alkaline media, and has broad application prospects. DETAILED DESCRIPTION

[0032] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0033] Graphene oxide, with a purity of >99%, a thickness of <5 nm, and an oxygen content of approximately 35%, was purchased from Jiangsu Xianfeng Nanomaterial Technology Co., Ltd.; polytetrafluoroethylene micropowder, with a water content of <0.05%, was purchased from Shenyang Wuliang Technology Co., Ltd.; Teflon primer was purchased from Chemours 420G-703; and Augeo SL-191 was purchased from Rhodia.

[0034] Example 1

[0035] This embodiment provides a method for preparing an anti-corrosion Teflon coating, comprising the following steps:

[0036] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 100°C for a total dose of 12kGy. 2g of glycidyl methacrylate, 0.01g of ammonium ferrous sulfate, and 0.02g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 60°C with stirring for 3h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0037] S2. Add 10 g of graphene oxide to 200 mL of water, add 3 g of dopamine hydrochloride, and 0.5 g of catalyst, heat to 45°C, stir and react for 1 h, filter, wash, and dry to obtain modified graphene oxide.

[0038] The catalyst is a Tris-HCl solution with a pH of 9;

[0039] S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 7 h to obtain modified graphene;

[0040] S4. 3 g of phosphorus oxychloride and 10 g of modified graphene were added to 200 mL of solvent, heated to 75°C, stirred for 2 h, centrifuged, washed, and dried to obtain a composite;

[0041] S5. Add 10 g of modified Teflon powder and 3 g of the compound to 75 g of Teflon primer and stir for 7 h to prepare an anti-corrosion Teflon coating.

[0042] Example 2

[0043] This embodiment provides a method for preparing an anti-corrosion Teflon coating, comprising the following steps:

[0044] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 150°C for a total dose of 15kGy. 3g of glycidyl methacrylate, 0.02g of ammonium ferrous sulfate, and 0.05g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 70°C with stirring for 5h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0045] S2. Add 10 g of graphene oxide to 200 mL of water, add 4 g of dopamine hydrochloride, and 1 g of catalyst, heat to 55°C, stir and react for 3 h, filter, wash, and dry to obtain modified graphene oxide.

[0046] The catalyst is a Tris-HCl solution with a pH of 10;

[0047] S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 10 h to obtain modified graphene;

[0048] S4. 4 g of phosphorus oxychloride and 10 g of modified graphene were added to 200 mL of solvent, heated to 85°C, stirred for 4 h, centrifuged, washed, and dried to obtain a composite;

[0049] S5. Add 10 g of modified Teflon powder and 5 g of the compound to 85 g of Teflon primer, stir and react for 10 hours to obtain an anti-corrosion Teflon coating.

[0050] Example 3

[0051] This embodiment provides a method for preparing an anti-corrosion Teflon coating, comprising the following steps:

[0052] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 125°C for a total dose of 13kGy. 2.5g of glycidyl methacrylate, 0.015g of ammonium ferrous sulfate, and 0.03g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 65°C with stirring for 4h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0053] S2. Add 10 g of graphene oxide to 200 mL of water, add 3.5 g of dopamine hydrochloride, and 0.7 g of catalyst, heat to 50°C, stir and react for 2 h, filter, wash, and dry to obtain modified graphene oxide.

[0054] The catalyst is a Tris-HCl solution with a pH of 9.5;

[0055] S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 8 h to obtain modified graphene;

[0056] S4. 3.5 g of phosphorus oxychloride and 10 g of modified graphene were added to 200 mL of solvent, heated to 80°C, stirred for 3 h, centrifuged, washed, and dried to obtain a composite;

[0057] S5. Add 10 g of modified Teflon powder and 4 g of the compound to 80 g of Teflon primer and stir for 8 h to obtain an anti-corrosion Teflon coating.

[0058] Comparative Example 1

[0059] Compared with embodiment 3, the difference is that step S2 is not performed.

[0060] The details are as follows:

[0061] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 125°C for a total dose of 13kGy. 2.5g of glycidyl methacrylate, 0.015g of ammonium ferrous sulfate, and 0.03g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 65°C with stirring for 4h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0062] S2. The graphene oxide was reduced with hydrazine hydrate vapor for 8 h to obtain graphene;

[0063] S3. 3.5 g of phosphorus oxychloride and 10 g of graphene were added to 200 mL of solvent, heated to 80°C, stirred for 3 h, centrifuged, washed, and dried to obtain a composite;

[0064] S4. Add 10 g of modified Teflon powder and 4 g of the compound to 80 g of Teflon primer and stir for 8 h to obtain an anti-corrosion Teflon coating.

[0065] Comparative Example 2

[0066] Compared with embodiment 3, the difference is that step S3 is not performed.

[0067] The details are as follows:

[0068] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 125°C for a total dose of 13kGy. 2.5g of glycidyl methacrylate, 0.015g of ammonium ferrous sulfate, and 0.03g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 65°C with stirring for 4h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0069] S2. Add 10 g of graphene oxide to 200 mL of water, add 3.5 g of dopamine hydrochloride, and 0.7 g of catalyst, heat to 50°C, stir and react for 2 h, filter, wash, and dry to obtain modified graphene oxide.

[0070] The catalyst is a Tris-HCl solution with a pH of 9.5;

[0071] S3. 3.5 g of phosphorus oxychloride and 10 g of modified graphene oxide were added to 200 mL of solvent, heated to 80°C, stirred for 3 h, centrifuged, washed, and dried to obtain a composite;

[0072] S4. Add 10 g of modified Teflon powder and 4 g of the compound to 80 g of Teflon primer and stir for 8 h to obtain an anti-corrosion Teflon coating.

[0073] Comparative Example 3

[0074] Compared with embodiment 3, the difference is that step S4 is not performed.

[0075] The details are as follows:

[0076] S1. 10g of polytetrafluoroethylene powder was added to 200mL of Augeo SL-191 solvent and irradiated at 125°C for a total dose of 13kGy. 2.5g of glycidyl methacrylate, 0.015g of ammonium ferrous sulfate, and 0.03g of concentrated sulfuric acid were also added. Nitrogen was introduced and the mixture was heated to 65°C with stirring for 4h. After the reaction, the mixture was extracted with acetone for 24h and dried to obtain modified Teflon powder.

[0077] S2. Add 10 g of graphene oxide to 200 mL of water, add 3.5 g of dopamine hydrochloride, and 0.7 g of catalyst, heat to 50°C, stir and react for 2 h, filter, wash, and dry to obtain modified graphene oxide.

[0078] The catalyst is a Tris-HCl solution with a pH of 9.5;

[0079] S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 8 h to obtain modified graphene;

[0080] S4. Add 10 g of modified Teflon powder and 4 g of modified graphene to 80 g of Teflon primer and stir for 8 h to prepare an anti-corrosion Teflon coating.

[0081] Comparative Example 4

[0082] Compared with Example 3, the difference is that in step S5, the modified Teflon powder is replaced by an equal amount of polytetrafluoroethylene powder.

[0083] The details are as follows:

[0084] S1. Add 10 g of graphene oxide to 200 mL of water, add 3.5 g of dopamine hydrochloride, and 0.7 g of catalyst, heat to 50°C, stir and react for 2 h, filter, wash, and dry to obtain modified graphene oxide.

[0085] The catalyst is a Tris-HCl solution with a pH of 9.5;

[0086] S2. The modified graphene oxide was reduced with hydrazine hydrate vapor for 8 h to obtain modified graphene;

[0087] S3. 3.5 g of phosphorus oxychloride and 10 g of modified graphene were added to 200 mL of solvent, heated to 80°C, stirred for 3 h, centrifuged, washed, and dried to obtain a composite;

[0088] S4. Add 10 g of polytetrafluoroethylene powder and 4 g of the compound to 80 g of Teflon primer and stir for 8 h to prepare an anti-corrosion Teflon coating.

[0089] Test Example 1

[0090] The anti-corrosion Teflon coatings prepared in Examples 1-3 and Comparative Examples 1-4 were sprayed onto primed stainless steel surfaces to a thickness of approximately 20 μm. The pencil hardness of the coatings was measured according to GB / T 6739-2006. The scratch resistance of the coatings was measured using a scratch tester according to ASTM D2197-2016. The film adhesion was tested according to GB / T 9286-1998. The test pieces were scored into 5×5 squares with a blade and taped with transparent tape. The tape was removed and the film integrity was observed. The results are shown in Table 1.

[0091] Table 1

[0092] Group Hardness (H) Scratch resistance (kg) Adhesion (grade) Example 1 3 10 0 Example 2 3 11 0 Example 3 3 12 0 Comparative Example 1 1 5 2 Comparative Example 2 2 6 1 Comparative Example 3 2 8 1 Comparative Example 4 1 5 3

[0093] It can be seen from the above table that the anti-corrosion Teflon coatings prepared in Examples 1-3 of the present invention have good comprehensive properties.

[0094] Test Example 2

[0095] The anti-corrosion Teflon coatings prepared in Examples 1-3 and Comparative Examples 1-4 were sprayed onto primed stainless steel surfaces to a thickness of approximately 20 μm. Testing was performed according to the requirements of Method A of GB / T 9274-1988. After soaking at room temperature for 14 days, the coatings were removed, cleaned, and immediately inspected for softening, blistering, and other signs. The acid and alkali resistance of the coatings was determined according to GB1763-1979. Test specimens were placed in an acid-base test kit, with dilute hydrochloric acid added to the left side and NaOH solution added to the right side. The coatings were observed every hour for cracking and damage, and the time from solution addition to film damage was recorded. The results are shown in Table 2.

[0096] Table 2

[0097] Group Kerosene resistance (RP-3 kerosene, 23±2℃, 14d) Gasoline resistance (180# gasoline, 23±2℃, 14d) Hydraulic oil resistance (15# hydraulic oil, 23±2℃, 14d) Acid resistance (h) Alkali resistance (h) Example 1 No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking 157 172 Example 2 No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking 159 174 Example 3 No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking No softening, no blistering, no wrinkling, no cracking 162 175 Comparative Example 1 Softening, blistering, wrinkling, and cracking Softening, blistering, wrinkling, and cracking Softening, blistering, wrinkling, and cracking 117 132 Comparative Example 2 Slightly soft, slightly bubbling, slightly wrinkled and cracked Slightly soft, slightly bubbling, slightly wrinkled and cracked Slightly soft, slightly bubbling, slightly wrinkled and cracked 135 147 Comparative Example 3 Slightly soft, slightly bubbling, slightly wrinkled and cracked Slightly soft, slightly bubbling, slightly wrinkled and cracked Slightly soft, slightly bubbling, slightly wrinkled and cracked 128 139 Comparative Example 4 Softening, blistering, wrinkling, and cracking Softening, blistering, wrinkling, and cracking Softening, blistering, wrinkling, and cracking 78 85

[0098] It can be seen from the above table that the anti-corrosion Teflon coatings prepared in Examples 1-3 of the present invention have good corrosion resistance.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing an anti-corrosion Teflon coating, characterized in that: The specific steps include: S1. 10 parts by weight of polytetrafluoroethylene powder was added to Augeo SL-191 solvent and irradiated at 100-150°C for a total irradiation dose of 12-15 kGy. Then, 2-3 parts by weight of glycidyl methacrylate, 0.01-0.02 parts by weight of ammonium ferrous sulfate, and 0.02-0.05 g of concentrated sulfuric acid were added. Nitrogen was introduced and the mixture was heated to 60-70°C with stirring for 3-5 hours. After the reaction, the mixture was extracted with acetone for 24 hours and dried to obtain modified Teflon powder. S2. Add 10 parts by weight of graphene oxide to water, add 3-4 parts by weight of dopamine hydrochloride and 0.5-1 parts by weight of a catalyst, heat to 45-55°C, stir and react for 1-3 hours, filter, wash, and dry to obtain modified graphene oxide; The catalyst is a Tris-HCl solution with a pH of 9-10; S3. The modified graphene oxide was reduced with hydrazine hydrate vapor for 7-10h to obtain modified graphene; S4. 3-4 parts by weight of phosphorus oxychloride and 10 parts by weight of modified graphene were added to a solvent, heated to 75-85 ° C, stirred for 2-4h, centrifuged, washed, and dried to obtain a composite; S5. Add 10 parts by weight of modified Teflon powder and 3-5 parts by weight of the compound to 75-85 parts by weight of Teflon primer, and stir the reaction for 7-10 hours to obtain an anti-corrosion Teflon coating.

2. An anti-corrosion Teflon coating, characterized in that: The anti-corrosion Teflon coating is prepared by the preparation method described in claim 1.

3. Use of the anti-corrosion Teflon coating according to claim 2 in preparing kitchenware coatings.