Seawater anti-corrosion high-molecular polymer film and preparation method thereof

Abstract

The invention discloses a seawater anticorrosion high-molecular polymer film and a preparation method thereof, and belongs to the field of high-molecular materials. The seawater anti-corrosion high-molecular polymer film comprises the following components in parts by weight: 65-80 parts of polyamide 1010, 1-9 parts of an anti-corrosion modifier, 0.2-0.6 part of an antioxidant and 0.2-1.0 part of a lubricant. The preparation method comprises the following four steps: preparation of an anti-corrosion modifier, preparation of modified polyamide, preparation of an anti-corrosion film material, and preparation of the required anti-corrosion film from the granulated material in an injection molding or coating manner. Malonate is adopted as a bridging molecule and is subjected to an ester aminolysis reaction with polyamide, N-fluoro-2, 4, 6-trimethylpyridinium trifluoromethanesulfonic acid is used for fluorinating a polyamide high polymer material and an active methylene site of malonic acid, a more stable C-F bond is introduced, and the stability of polyamide molecules is greatly improved; and the corrosion resistance is enhanced.

Description

Technical Field

[0001] The present invention relates to the field of polymer materials, and particularly relates to a seawater anti-corrosion polymer film and a preparation method thereof. Background Art

[0002] Seawater is rich in various inorganic salts at high concentrations. When various devices are immersed in seawater for a long time, their corrosion rate is much higher than that in fresh water areas. Marine microorganisms and animals attach to the surface of the devices, and the metabolites they secrete will also accelerate the corrosion of the device surface. Therefore, these devices are generally made of corrosion-resistant materials, or a corrosion-resistant layer is added to the surface of the devices to extend the service life of the devices and enhance the reliability of the devices.

[0003] Polyamide (nylon, PA) is a polyamide polymer material. According to different synthetic materials, it can be divided into aliphatic PA, aromatic PA, semi-aromatic PA, alicyclic PA, heterocyclic PA, etc. It has good thermoplasticity, and its molecular structure has excellent mechanical strength, wear resistance, self-lubrication, corrosion resistance and good molding processability.

[0004] At present, technologies such as mineral grease coating protection, organic coating protection, ceramic coating protection, and rust preventives are mainly used in the field of marine anti-corrosion. The anti-corrosion layers applied by these methods have disadvantages such as uneven coating thickness, easy peeling, pitting corrosion, and durability. And many polymer materials themselves have certain corrosion resistance. At present, many studies have used physical or chemical modification methods to modify polymer materials for corrosion resistance. Physical modification often uses adding anti-corrosion components to enhance the seawater corrosion resistance of the material. For example, adding polytetrafluoroethylene to the material, but the price of polytetrafluoroethylene is relatively high. The commonly used method of chemical modification is to use a new polymer initiator to prepare a polymer material with a new structure. Its preparation method is generally more complex, the price of the starting materials is also very high, and the product performance of the polymer prepared has large batch-to-batch differences, low quality reliability, and the preparation requires huge R & D and equipment costs. Therefore, using commercially available polymer materials with mature technologies and modifying them to prepare materials that meet special requirements is an efficient and economical development idea. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to provide a seawater anti-corrosion polymer film, and another object of the present invention is to provide a preparation method of a seawater anti-corrosion polymer film.

[0006] Technical Solution: A seawater anti-corrosion polymer film includes polyamide 1010, an anti-corrosion modifier, an antioxidant, and a lubricant;

[0007] Among them, the anti-corrosion modifier is composed of a malonic acid ester with a structure of formula 1 and a fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate,

[0008]

[0009] In the compound of Formula 1 structure, R is selected from methyl, ethyl, and tert-butyl.

[0010] Preferably, the material comprises 70 - 85 parts by weight of polyamide 1010, 1 - 9 parts of anti-corrosion modifier, 0.2 - 0.6 parts of antioxidant, and 0.2 - 1.0 parts of lubricant.

[0011] Preferably, the weight ratio of malonic ester to fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate in the anti-corrosion modifier is 1 - 5:2.

[0012] Preferably, the antioxidant is one or a combination of two or more of phenolic, organic amine, and carboxylic ester antioxidants.

[0013] Preferably, the lubricant is one of stearates and amides.

[0014] The preparation method of the above seawater anti-corrosion polymer film comprises the following preparation steps:

[0015] S1. Preparation of anti-corrosion modifier: Add malonic ester to the methyltetrahydrofuran solution, stir and disperse it, then slowly add sodium hydride to the reaction system, control the reaction temperature not exceeding 10°C, and stir and react for 1 - 2 h; Add the fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to the reaction system in batches. After the reaction is completed, add methanol to quench the reaction; Evaporate the solvent to obtain the anti-corrosion modifier; wherein, the mass ratio of malonic ester, sodium hydride, and fluorinating agent is 1 - 5:0.7:2;

[0016] S2. Preparation of modified polyamide: Place polyamide 1010 in a vacuum drying oven with anhydrous calcium chloride and vacuum dry it at 50 - 70°C; Mix 65 - 80 parts of the dried polyamide 1010 and 1 - 9 parts of the anti-corrosion modifier prepared in step S1 and heat to 120 - 150°C, and keep warm for 5 - 10 h to obtain the modified polyamide;

[0017] S3. Preparation of anti-corrosion film material: Add the mixed material of the modified polyamide prepared in step S2, 0.2 - 0.6 parts of antioxidant, and 0.2 - 1.0 parts of lubricant to a screw extruder, extrude, cool and draw into strips, and cut into pellets;

[0018] S4. Prepare the required anti-corrosion film by extrusion blow molding or coating of the material cut into pellets in step S3.

[0019] Preferably, in step S2, the water content of the dried polyamide 1010 is not higher than 0.2%.

[0020] Beneficial effects:

[0021] (1) Using malonic ester as a bridging molecule, through an ester-amineolysis reaction with polyamide, and simultaneously using N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to fluorinate the polyamide polymer material and the active methylene position of malonic acid, introducing a more stable C-F bond, greatly improving the stability of the polyamide molecule and enhancing its corrosion resistance.

[0022] (2) The preparation method of this process is simple. By using commercially available and inexpensive PA1010 and malonic ester as materials, the corrosion resistance of polyamide is greatly improved through chemical modification. No special equipment is required, and there is no need to add expensive polytetrafluoroethylene required for conventional physical blending modification or polyfluorinated starting materials required for chemical modification. At the same time, it avoids the disadvantage of having to develop a new polyamide synthesis route in conventional chemical modification, greatly reducing the R & D, equipment, and material costs, and improving the quality stability of the product. It is an economical and commercially suitable process route. Detailed implementation mode

[0023] To make the technical solution of the present invention clearer, the following further describes the present invention in detail with specific embodiments.

[0024] Example 1

[0025] Add 10 kg of dimethyl malonate to 100 kg of methyl tetrahydrofuran solution. After stirring and dispersing for 10 min, slowly add 1.4 kg of sodium hydride to the reaction system, control the reaction temperature not to exceed 10 °C, and stir and react for 2 h; add 4 kg of N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to the reaction system in five batches. After the reaction is completed, add 11 kg of methanol and stir and react for 0.5 h; evaporate the solvent until no liquid drips out, and continue distilling for 1 h to obtain an anti-corrosion modifier.

[0026] Place 81 kg of polyamide 1010 (Swiss EMS XE-4019) in a vacuum drying oven with 2 kg of anhydrous calcium chloride added, heat up to 50 °C and vacuum dry for more than 6 h, and detect the water content of the polyamide to be 0.12%; mix 80 kg of the dried polyamide 1010 and 6 kg of the anti-corrosion modifier and heat to 150 °C, and keep warm for 8 h to obtain modified polyamide;

[0027] After mixing 80 kg of the modified polyamide, 0.4 kg of antioxidant 2,6-di-tert-butyl-4-methylphenol, and 0.5 kg of lubricant magnesium stearate evenly, add them to a screw extruder. Set the temperature of the first section to 200 °C, and the temperatures of the other sections are 210 - 220 - 220 - 230 °C. The screw speed is 200 r / min. After extrusion, send it into water at 20 °C for cooling, drawing, and pelletizing.

[0028] Coated film formation: Add the above-mentioned granulated materials to 2 times the weight of dimethylacetamide, stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution, then stand for defoaming at 80 °C for 1 h, and then pour the casting solution onto the glass plate of the film scraping machine to scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and stand for 5 min to obtain Anticorrosion Film 1.

[0029] Extrusion blow molding: Add the above-mentioned granulated materials to a single-screw extrusion blow molding machine for blow molding. The temperatures of each section of the extruder are 200 - 205 - 205 - 215 - 230 °C in sequence, the temperature of the die of the blow molding head is 250 °C, the blow-up ratio is 3.2, and the traction speed is 6 m / min.

[0030] Example 2

[0031] Add 20 kg of diethyl malonate to 200 kg of methyltetrahydrofuran solution, stir and disperse for 10 min, then slowly add 14 kg of sodium hydride to the reaction system, control the reaction temperature not to exceed 10 °C, and stir and react for 1 h; add 40 kg of N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to the reaction system in five batches. After the reaction is completed, add 11 kg of methanol and stir and react for 0.5 h; evaporate the solvent until no liquid drips out, and continue distillation for 1 h to obtain the anticorrosion modifier.

[0032] Place 81 kg of polyamide 1010 in a vacuum drying oven containing 2 kg of anhydrous calcium chloride, heat up to 60 °C and vacuum dry for more than 6 h, and detect the water content of polyamide to be 0.10%; mix 65 kg of the dried polyamide 1010 and 1 kg of the anticorrosion modifier and heat to 120 °C, keep warm for 5 h to obtain the modified polyamide;

[0033] After uniformly mixing the materials of 70 kg of the modified polyamide, 0.2 kg of antioxidant octylated diphenylamine, and 0.2 kg of lubricant stearamide, add them to a screw extruder. The temperature of the first section is set at 200 °C, and the temperatures of other sections are 210 - 220 - 220 - 230 °C. The screw speed is 200 r / min. After extrusion, it is sent into water at 20 °C for cooling, drawing into strips, and granulating.

[0034] Add the above-mentioned granulated materials to 2 times the weight of dimethylacetamide, stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution, then stand for defoaming at 80 °C for 1 h, and then pour the casting solution onto the glass plate of the film scraping machine to scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and stand for 5 min to obtain Anticorrosion Film 2.

[0035] Example 3

[0036] Add 40 kg of di-tert-butyl malonate to 300 kg of methyl tetrahydrofuran solution. After stirring and dispersing for 10 min, slowly add 7 kg of sodium hydride to the reaction system, control the reaction temperature not exceeding 10 °C, and stir and react for 1 h; add 20 kg of N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to the reaction system in five batches. After the reaction is completed, add 10 kg of methanol and stir and react for 0.5 h; evaporate the solvent until no liquid drips out, and continue distillation for 1 h to obtain the anti-corrosion modifier.

[0037] Place 81 kg of polyamide 1010 in a vacuum drying oven containing 2 kg of anhydrous calcium chloride, heat up to 70 °C and vacuum dry for more than 6 h, and detect the water content of polyamide to be 0.03%; mix 80 kg of the dried polyamide 1010 and 9 kg of the anti-corrosion modifier and heat to 150 °C, and keep warm for 10 h to obtain the modified polyamide;

[0038] After uniformly mixing the materials of 85 kg of the modified polyamide, 0.6 kg of antioxidant 1010, and 1.0 kg of lubricant magnesium stearate, add them to a screw extruder. Set the temperature of the first section to 200 °C, and the temperatures of the other sections are 210 - 220 - 220 - 230 °C. The screw speed is 200 r / min. After extrusion, send it into water at 20 °C for cooling, drawing, and pelletizing.

[0039] Add the above pelletized materials to 2 times the weight of dimethylacetamide, stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution, then stand and defoam at 80 °C for 1 h, and then pour the casting solution onto the glass plate of a film scraping machine to scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and stand for 5 min to obtain the anti-corrosion film 3.

[0040] Comparative Example 1

[0041] Add 80 kg of polyamide 1010, 0.4 kg of antioxidant 330, and 0.5 kg of lubricant oleic acid amide to 2 times the weight of dimethylacetamide, stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution, then stand and defoam at 80 °C for 1 h, and then pour the casting solution onto the glass plate of a film scraping machine to scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and stand for 5 min to obtain the anti-corrosion film 4.

[0042] Comparative Example 2

[0043] Place 81 kg of polyamide 1010 in a vacuum drying oven containing 2 kg of anhydrous calcium chloride, heat up to 50 °C and vacuum dry for more than 6 h, and detect the water content of polyamide to be 0.2%; mix 80 kg of the dried polyamide 1010 and 2 kg of N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate and heat to 150 °C, and keep warm for 8 h to obtain the modified polyamide;

[0044] After mixing 80 kg of modified polyamide, 0.4 kg of antioxidant 3300, and 0.5 kg of lubricant magnesium stearate evenly, add them to a screw extruder. Set the temperature of the first section to 200 °C, and the temperatures of the other sections to 210 - 220 - 220 - 230 °C. Set the screw speed to 200 r / min. After extrusion, send it into water at 20 °C for cooling, strand pelletization.

[0045] Add the above pelletized material to dimethylacetamide with a weight twice that of the material, and stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution. Then, let it stand for 1 h at 80 °C for degassing. Then, pour the casting solution onto the glass plate of a film scraping machine and scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and let it stand for 5 min to obtain anti-corrosion film 5.

[0046] Comparative Example 3

[0047] Place 81 kg of polyamide 1010 in a vacuum drying oven with 2 kg of anhydrous calcium chloride, heat it up to 50 °C and vacuum dry for more than 6 h, and detect the water content of the polyamide to be 0.17%; mix 80 kg of the dried polyamide 1010 and 2 kg of dimethyl malonate and heat to 150 °C, keep warm for 8 h to obtain modified polyamide;

[0048] After mixing 80 kg of modified polyamide, 0.4 kg of antioxidant 1010, and 0.5 kg of lubricant magnesium stearate evenly, add them to a screw extruder. Set the temperature of the first section to 200 °C, and the temperatures of the other sections to 210 - 220 - 220 - 230 °C. Set the screw speed to 200 r / min. After extrusion, send it into water at 20 °C for cooling, strand pelletization.

[0049] Add the above pelletized material to dimethylacetamide with a weight twice that of the material, and stir at a constant temperature of 80 °C for 2 h to prepare a uniform and semi-transparent casting solution. Then, let it stand for 1 h at 80 °C for degassing. Then, pour the casting solution onto the glass plate of a film scraping machine and scrape out a film with a thickness of about 300 nm. After scraping the film, quickly place the glass plate in an aqueous solution at 25 °C and let it stand for 5 min to obtain anti-corrosion film 6.

[0050] Anti-corrosion performance test:

[0051] Immerse the anti-corrosion films prepared in the above examples and comparative examples in natural seawater, set the temperature to -10 °C, 20 °C, 60 °C, use an ellipsometer to measure the thickness change every three months, and observe the corrosion pit situation on the film surface with a scanning electron microscope. The results are shown in the following table.

[0052] Table 1 Test results of anti-corrosion films in examples and comparative examples

[0053]

[0054]

[0055] Note: 1. Y indicates that this component is added to the formula, and N indicates that this component is not added.

[0056] 2. The thickness data is the percentage change rate of the thickness at the test point and the thickness at day 0. The change rate % = (thickness at day 0 - thickness at the test point) / thickness at day 0 × 100%

[0057] The above results show that for Film 4 without the anti-corrosion modifier, as the temperature increases, its thickness change becomes larger and larger, reaching a maximum of 15.8%, indicating that seawater has great corrosiveness to it during long-term use. At the same time, for the anti-corrosion films 1 - 3 modified with malonic ester and fluorinating agent, even when inspected at 60°C for 12 months, there are still no corrosion points, and the lowest thickness change rate can reach 0, indicating that the anti-corrosion films prepared by this technical solution have good seawater corrosion resistance and excellent effects. For the anti-corrosion film 5 prepared by only adding the fluorinating agent for modification, the performance improvement is limited, and for the anti-corrosion film 6 prepared by only adding malonic ester, there is no significant difference from Film 4.

[0058] The comprehensive results show that the polymer film prepared by this technical solution has good seawater corrosion resistance. The anti-corrosion modifiers used in it play a synergistic anti-corrosion role. Malonic ester can reduce the content of free amino groups in polyamide, and at the same time bridge fluorine atoms, increase the number of C-F bonds in the polymer structure, and improve the anti-corrosion performance.

[0059] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A seawater anti-corrosion polymer film, characterized in that, It includes polyamide 1010, an anticorrosive modifier, an antioxidant, and a lubricant; Among them, the anticorrosive modifier is composed of a malonic acid ester with the structure of formula 1 and a fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate, R in the compound with the structure of formula 1 is selected from methyl, ethyl, and tert-butyl.

2. The seawater anti-corrosion polymer composite film according to claim 1, wherein: The polymeric film includes 65 - 80 parts by weight of polyamide 1010, 1 - 9 parts of an anticorrosive modifier, 0.2 - 0.6 parts of an antioxidant, and 0.2 - 1.0 parts of a lubricant.

3. The seawater anti-corrosion polymer composite film according to claim 1, characterized in that: The weight ratio of the malonic acid ester to the fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate in the anticorrosive modifier is 1 - 5:

2.

4. The seawater anti-corrosion polymer composite film according to claim 1, characterized in that: The antioxidant is one or a combination of two or more of phenolic, organic amine, and carboxylic ester antioxidants.

5. The seawater corrosion-resistant polymer composite film according to claim 1, wherein: The lubricant is one of stearates and amides.

6. A preparation method of the seawater anti-corrosion polymer composite membrane according to any one of claims 1 to 5, characterized in that, It includes the following steps: S1. Preparation of the anticorrosive modifier: Add the malonic acid ester to the methyl tetrahydrofuran solution, stir and disperse it, then slowly add sodium hydride to the reaction system, control the reaction temperature not exceeding 10°C, and stir and react for 1 - 2 h; Add the fluorinating agent N-fluoro-2,4,6-trimethylpyridinium trifluoromethanesulfonate to the reaction system in batches. After the reaction is completed, add methanol to quench the reaction; Evaporate the solvent to obtain the anticorrosive modifier; Among them, the mass ratio of the malonic acid ester, sodium hydride, and the fluorinating agent is 1 - 5:0.7:2; S2. Preparation of the modified polyamide: Place polyamide 1010 in a vacuum drying oven with anhydrous calcium chloride and vacuum dry it at 50 - 70°C; Mix 65 - 80 parts of the dried polyamide 1010 and 1 - 9 parts of the anticorrosive modifier prepared in step S1 and heat it to 120 - 150°C, and keep it warm for 5 - 10 h to obtain the modified polyamide; S3. Preparation of the anticorrosive film material: Add the mixture of the modified polyamide prepared in step S2, 0.2 - 0.6 parts of an antioxidant, and 0.2 - 1.0 parts of a lubricant to a screw extruder, extrude it, then cool, draw into strips, and pelletize; S4. Prepare the required anticorrosive film from the pelletized material in step S3 by extrusion blow molding or coating.

7. The preparation method of the seawater anti-corrosion polymer film according to claim 6, characterized in that: In step S2, the water content of the dried polyamide 1010 is not higher than 0.2%.

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