Acid-alkali-resistant, heat-resistant, heavy-duty anticorrosive coating and preparation method thereof

Abstract

The present invention discloses an acid-base-resistant, heat-resistant, heavy-duty anticorrosion coating and a preparation method thereof, wherein the acid-base-resistant, heat-resistant, heavy-duty anticorrosion coating comprises a modified epoxy resin, a solvent-based modified fluorocarbon resin, modified silica, a curing agent, and propylene glycol methyl ether acetate; the solvent-based modified fluorocarbon resin is prepared by modifying the fluorocarbon resin with (acryloyloxymethyl)phenylethyltrimethoxysilane; the modified silica is prepared by modifying silica with a silane coupling agent. The acid-base-resistant, heat-resistant, heavy-duty anticorrosion coating provided by the present invention is prepared by modifying the fluorocarbon resin with (acryloyloxymethyl)phenylethyltrimethoxysilane, and adding silica modified by a silane coupling agent, which can not only significantly improve the temperature resistance of the coating, but also improve the salt-alkali resistance and salt spray resistance of the coating, so that it can be widely used in complex and harsh environments in a long-term and stable manner.

Description

Technical Field

[0001] The invention relates to the technical field of heavy-duty anti-corrosion coatings, and in particular to an acid-, alkali-, and temperature-resistant heavy-duty anti-corrosion coating and a preparation method thereof. Background Art

[0002] Corrosion is the process of damage and breakage of metal, concrete, wood and other substrates under physical, chemical or electrochemical effects. Every year, the economic losses caused by corrosion are huge, and it also poses a safety hazard to its future use. Therefore, anti-corrosion research has received more and more attention. Among the many anti-corrosion methods, anti-corrosion coatings are recognized as the most economical, convenient and safest method.

[0003] As the public's demands for environmental protection become more urgent and stringent, the development of low-energy, low-pollution, high-performance heavy-duty anti-corrosion coatings has become one of the current research hotspots.

[0004] The concept of heavy-duty anti-corrosion coatings originated in Japan in the 1960s. It refers to coatings with long service life that are used in harsh corrosive environments. The so-called harsh corrosive environment refers to a highly corrosive environment. According to the definition of ISO12944-2, it refers to an atmospheric environment of C4 (high), C5-I (very high industrial), C5-M (very high marine) and an environment of 1m2 immersed in seawater or saline water. There is no exact definition of the so-called long service life. It is generally believed that it should be more than 5 years of service life, that is, the medium or high coating service life specified in ISO12944-5.

[0005] The existing heavy-duty anti-corrosion coatings have the following characteristics: high film thickness, good surface treatment performance, application of new resins and pigments and fillers, etc. Among them, fluorocarbon resin is a fluoroethylene-alkyl vinyl ether / ester alternating copolymer that can be cured at room temperature. By introducing different alkyl vinyl ethers / esters, the resin is endowed with water solubility, good adhesion, compatibility with fillers and other properties. At the same time, the fluoroethylene monomer can well protect the main chain, making the resin have excellent anti-aging, weather resistance and chemical stability. It is a coating resin matrix with great potential and broad prospects.

[0006] Fluorocarbon resin has outstanding characteristics such as strong chemical corrosion resistance, low dielectric constant, good curing at room temperature, etc. However, the temperature resistance of fluorocarbon resin in the prior art still needs to be improved, and fluorocarbon resin is susceptible to erosion and abrasive wear. Due to plastic deformation and crack initiation, its acid and alkali resistance and salt spray resistance are insufficient, which shortens the service life of fluorocarbon resin heavy-duty anti-corrosion coatings in complex environments.

[0007] Therefore, there is an urgent need for a heavy-duty anti-corrosion coating that has excellent heat resistance and acid and alkali resistance by modifying fluorocarbon resin and compounding other components. Summary of the invention

[0008] Purpose of the invention: In view of the defects of the prior art, the purpose of the present invention is to provide a heavy-duty anti-corrosion coating and a preparation method thereof which has excellent acid, alkali and temperature resistance by modifying fluorocarbon resin and composite-modified silica.

[0009] Technical solution:

[0010] An acid-, alkali-, temperature-resistant and heavy-duty anticorrosive coating comprising a modified epoxy resin, a solvent-based modified fluorocarbon resin, modified silica, a curing agent and propylene glycol methyl ether acetate;

[0011] The solvent-based modified fluorocarbon resin is prepared by modifying the fluorocarbon resin with (acryloxymethyl)phenylethyltrimethoxysilane;

[0012] The modified silicon dioxide is prepared by modifying silicon dioxide with a silane coupling agent.

[0013] The solvent-based modified fluorocarbon resin in the present invention is prepared by modifying the fluorocarbon resin with (acryloyloxymethyl)phenylethyltrimethoxysilane, and the silicon hydrogen groups generated by catalytic hydrolysis react with the carboxyl groups in the fluorocarbon resin, thereby successfully grafting the silane structure and the benzene ring structure into the fluorocarbon resin.

[0014] Furthermore, the solvent-based modified fluorocarbon resin is prepared by the following steps: in a reactor, (acryloxymethyl)phenylethyltrimethoxysilane, fluorocarbon resin, deionized water and an organic solvent are added, heated to 70-90°C and stirred evenly, then an initiator is added, and the reaction is carried out for 6-8 hours and then cooled to obtain the solvent-based modified fluorocarbon resin.

[0015] The solvent-based modified fluorocarbon resin in the present invention, on the one hand, has a silane structure with excellent stability grafted into the fluorocarbon resin, which can significantly improve the heat resistance of the fluorocarbon resin, and the silane structure can improve the dispersibility of the fluorocarbon resin, making it evenly dispersed with other components, thereby improving the overall performance of the coating; on the other hand, the benzene ring structure with excellent stability and large steric hindrance can further improve the heat resistance, acid and alkali resistance and salt spray resistance of the fluorocarbon resin, and at the same time can further improve the dispersibility of the fluorocarbon resin and improve the overall performance of the coating.

[0016] Furthermore, the mass ratio of the (acryloyloxymethyl)phenylethyltrimethoxysilane to the fluorocarbon resin is 1:4-6; and the initiator is selected from one of dibutyltin dilaurate and dibutyltin diacetate.

[0017] Furthermore, the modified silica is prepared by the following steps: adding an organic solvent and silica to a reactor, adding a silane coupling agent after ultrasonic dispersion, heating to 80-90° C., reacting at a constant temperature for 8-12 hours under closed conditions, cooling, centrifuging, purifying, and drying to obtain the modified silica.

[0018] The modified silica in the present invention is prepared by modifying silica with a silane coupling agent. The silica modified with the silane coupling agent can be combined with the fluorocarbon resin in the coating in the form of a chemical bond. Based on the excellent stability of silica, the anti-corrosion ability of the coating can be improved, and a compact and dense network structure can be formed on the surface of the formed coating, thereby effectively improving its acid, alkali and salt spray resistance.

[0019] Furthermore, the mass ratio of the silicon dioxide to the silane coupling agent is 3-5:1; the silicon dioxide is selected from a silane coupling agent having a specific surface area of ​​200-300m 2 / g of silicon dioxide powder; the silane coupling agent is selected from one of 3-aminopropyltriethoxysilane and N-2-aminoethyl-3-aminopropyltriethoxysilane.

[0020] Furthermore, the modified epoxy resin is prepared by the following steps: in a reactor, bisphenol F epoxy resin, phenolic resin and catalyst are added, heated to 110-120° C. for reaction for 30-60 minutes, organic siloxane monomer is added with stirring, the temperature is raised to 140-150° C. for reaction for 1-2 hours, and then cooled and filtered to obtain the modified epoxy resin.

[0021] Furthermore, the mass ratio of the bisphenol F epoxy resin, the phenolic resin and the organosiloxane monomer is (1.2-1.5):(0.8-1):(0.3-0.5); the organosiloxane monomer is selected from one of vinyl triisopropoxy silane, octavinyl cyclotetrasiloxane or octamethyl cyclotetrasiloxane; and the catalyst is selected from one of triethylamine, tetraethylammonium bromide or triphenylphosphine.

[0022] Furthermore, the curing agent is selected from one of methyl ethyl ketone peroxide, m-phenylenediamine or diaminodiphenyl sulfone.

[0023] Furthermore, based on the total mass fraction being 100%, the mass percentage of each component is:

[0024] Modified epoxy resin 15-20%

[0025] Solvent-based modified fluorocarbon resin 45-60%

[0026] Modified silica 8-12%

[0027] Curing agent 3-5%

[0028] The balance is propylene glycol methyl ether acetate.

[0029] The preparation method of any of the above-mentioned acid-resistant, alkali-resistant, heat-resistant and heavy-duty anti-corrosion coatings comprises the following steps: weighing modified epoxy resin, solvent-based modified fluorocarbon resin, modified silica, curing agent and propylene glycol methyl ether acetate in proportion, mixing and dispersing them evenly to obtain the acid-resistant, alkali-resistant, heat-resistant and heavy-duty anti-corrosion coating.

[0030] Beneficial effects:

[0031] (1) The acid-resistant, alkali-resistant, heat-resistant, heavy-duty anti-corrosion coating provided by the present invention is prepared by modifying a fluorocarbon resin with (acryloyloxymethyl)phenylethyltrimethoxysilane and adding silica modified with a silane coupling agent. This can not only significantly improve the heat resistance of the coating, but also improve the salt-alkali resistance and salt spray resistance of the formed coating, so that it can be widely used in complex and harsh environments in a long-term and stable manner.

[0032] (2) In the acid-, alkali-, temperature-resistant and heavy-duty anti-corrosion coating provided by the present invention, the solvent-based modified fluorocarbon resin is prepared by modifying the fluorocarbon resin with (acryloxymethyl)phenylethyltrimethoxysilane, and the silicon hydrogen groups produced by catalytic hydrolysis react with the carboxyl groups in the fluorocarbon resin, thereby successfully grafting the silane structure and the benzene ring structure into the fluorocarbon resin.

[0033] (3) In the acid-, alkali-, and heat-resistant heavy-duty anti-corrosion coating provided by the present invention, on the one hand, a silane structure with excellent stability is grafted into the fluorocarbon resin, which can significantly improve the heat resistance of the fluorocarbon resin, and the silane structure can improve the dispersibility of the fluorocarbon resin, making it evenly dispersed with other components, thereby improving the overall performance of the coating; on the other hand, the benzene ring structure with excellent stability and large steric hindrance can further improve the heat resistance, acid-, alkali-, and salt spray resistance of the fluorocarbon resin, and at the same time can further improve the dispersibility of the fluorocarbon resin, thereby improving the overall performance of the coating.

[0034] (4) In the acid-resistant, alkali-resistant, heat-resistant and heavy-duty anti-corrosion coating provided by the present invention, modified silica is obtained by modifying silica with a silane coupling agent. The silica modified with the silane coupling agent can be combined with the fluorocarbon resin in the coating through chemical bonds. Based on the excellent stability of silica, the anti-corrosion ability of the coating can be improved, and a compact and dense network structure can be formed on the surface of the formed coating, thereby effectively improving its acid-resistant, alkali-resistant and salt spray-resistant abilities. DETAILED DESCRIPTION

[0035] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0036] The commercially available heavy-duty anti-corrosion coating is a polyurethane anti-corrosion coating purchased from Henan Aohui Industrial Coatings Co., Ltd.; the fluorocarbon resin is a fluorocarbon coating PVDF purchased from Shanghai Youcheng International Trade Co., Ltd.; and the remaining reagents and equipment are conventional reagents and equipment in this technical field.

[0037] Preparation of modified epoxy resin

[0038] The modified epoxy resin was prepared by the following steps:

[0039] In a reactor, 3 g of bisphenol F epoxy resin, 1.8 g of phenolic resin and 0.1 g of triethylamine were added, and the mixture was heated to 115° C. and reacted for 50 minutes. Then, 0.8 g of vinyl triisopropoxy silane was added with stirring, and the mixture was heated to 145° C. and reacted for 1 hour. After that, the mixture was cooled and filtered to obtain the modified epoxy resin.

[0040] Preparation of solvent-based modified fluorocarbon resin-1

[0041] The solvent-based modified fluorocarbon resin-1 was prepared by the following steps:

[0042] In the reactor, 3 g of (acryloyloxymethyl)phenylethyltrimethoxysilane, 15 g of fluorocarbon resin, 50 mL of deionized water and 50 mL of propylene glycol methyl ether acetate were added, heated to 80°C and stirred evenly, and then 0.3 g of dibutyltin dilaurate was added. After reacting for 8 hours, the reaction was cooled to obtain the solvent-based modified fluorocarbon resin-1.

[0043] Preparation of solvent-based modified fluorocarbon resin-2

[0044] The preparation method is basically the same as that of solvent-based modified fluorocarbon resin-1, except that (acryloyloxymethyl)phenylethyltrimethoxysilane is replaced by an equal amount of vinyltrimethoxysilane.

[0045] Preparation of modified silica-1

[0046] Modified silica-1 was prepared by the following steps:

[0047] In the reactor, 50 mL of propylene glycol methyl ether acetate and 5 g of silica powder were added, 1 g of 3-aminopropyltriethoxysilane was added after ultrasonic dispersion, and the mixture was heated to 85° C. and reacted at a constant temperature for 12 hours under closed conditions, followed by cooling, centrifugation, purification, and drying to obtain the modified silica-1.

[0048] Preparation of modified silica-2

[0049] The preparation method is basically the same as that of modified silica-1, except that 3-aminopropyltriethoxysilane is replaced by an equal amount of 3-aminopropyltriethoxysilane.

[0050] Example 1

[0051] The acid-, alkali-, heat-resistant and heavy-duty anticorrosion coating is prepared by the following steps:

[0052] Weigh the modified epoxy resin, solvent-based modified fluorocarbon resin-1, modified silicon dioxide, curing agent and propylene glycol methyl ether acetate in proportion, mix and disperse them evenly to obtain the acid-resistant, alkali-resistant and heat-resistant heavy-duty anticorrosive coating;

[0053] Taking the total mass fraction as 100%, the mass percentage of each component is:

[0054] Modified epoxy resin 15%

[0055] Solvent-based modified fluorocarbon resin-1 50%

[0056] Modified Silica-1 10%

[0057] Methyl Ethyl Ketone Peroxide 4%

[0058] The balance is propylene glycol methyl ether acetate.

[0059] Example 2

[0060] The same as Example 1, except that the total mass fraction is 100%, and the components and their mass percentages are changed to:

[0061] Modified epoxy resin 18%

[0062] Solvent-based modified fluorocarbon resin-1 55%

[0063] Modified silica-2 8%

[0064] Metaphenylenediamine 3%

[0065] The balance is propylene glycol methyl ether acetate.

[0066] Example 3

[0067] The same as Example 1, except that the total mass fraction is 100%, and the components and their mass percentages are changed to:

[0068] Modified epoxy resin 20%

[0069] Solvent-based modified fluorocarbon resin-1 60%

[0070] Modified Silica-1 12%

[0071] Diaminodiphenyl sulfone 5%

[0072] The balance is wollastonite.

[0073] Comparative Example 1

[0074] Commercially available heavy duty anti-corrosion coating.

[0075] Comparative Example 2

[0076] The method is basically the same as Example 1, except that the solvent-based modified fluorocarbon resin-1 is replaced by an equal amount of fluorocarbon resin.

[0077] Comparative Example 3

[0078] The method is basically the same as Example 1, except that the solvent-based modified fluorocarbon resin-1 is replaced by an equal amount of modified fluorocarbon resin-2.

[0079] Comparative Example 4

[0080] The method is basically the same as Example 1, except that the modified silica-1 is replaced by an equal amount of silica.

[0081] Performance Testing

[0082] The cold-rolled steel plate was sandblasted to control the roughness at Sa2.5, and the coatings of Examples 1-3 and Comparative Examples 1-4 were sprayed on the substrates respectively. After aging for 30 minutes after spraying, the coatings were placed in an oven and baked at 80°C for 30 minutes to obtain coatings with a dry film thickness of 80 to 100 μm.

[0083] Acid and alkali resistance test: According to the test standard of GB / T 9274-1988, the acid resistance and alkali resistance of the coatings prepared from the products of Examples 1-3 and Comparative Examples 1-4 were tested.

[0084] Salt spray resistance test: According to the test standard of GB / T1771-1991, the salt spray resistance of the coatings prepared from the products of Examples 1-3 and Comparative Examples 1-4 was tested.

[0085] Temperature resistance test: The coatings prepared from the products of Examples 1-3 and Comparative Examples 1-4 were placed in a 150°C environment for 16 hours and then naturally cooled for 8 hours as one cycle. The cycle was repeated until the coating showed obvious changes and the number of cycles was recorded.

[0086] The test results are shown in the following table:

[0087]

[0088] According to the comparison of the test results of Example 1 and Example 2, it can be seen that the modified silica in the acid-resistant, alkali-resistant, heat-resistant and heavy-duty anti-corrosion coating provided by the present invention can further improve the overall performance of the coating by modifying the silica with an aminosilane coupling agent.

[0089] According to the comparison of the test results of Examples 1-3 with those of Comparative Example 1, the acid-, alkali-, and heat-resistant heavy-duty anti-corrosion coating provided by the present invention has better acid-, alkali-, and temperature-resistant capabilities than the heavy-duty anti-corrosion coating in the prior art, and can have a longer service life in complex environments.

[0090] According to the comparison of the test results of Examples 1-3 and Comparative Examples 2-3, it can be seen that the solvent-based modified fluorocarbon resin in the acid-resistant, alkali-resistant and heat-resistant heavy-duty anti-corrosion coating provided by the present invention can significantly improve the coating's acid-resistant, alkali-resistant, salt spray-resistant and heat-resistant capabilities by heavily grafting silane structures and benzene ring structures onto the fluorocarbon resin.

[0091] According to the comparison of the test results of Examples 1-3 and Comparative Example 4, it can be seen that adding modified silicon dioxide to the acid-resistant, alkali-resistant and heat-resistant heavy-duty anti-corrosion coating provided by the present invention can further improve the coating's acid-resistant, alkali-resistant, salt spray-resistant and heat-resistant capabilities.

[0092] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A heavy-duty acid-, alkali-, temperature-resistant and anti-corrosion coating, characterized in that: Contains modified epoxy resin, solvent-based modified fluorocarbon resin, modified silica, curing agent and propylene glycol methyl ether acetate; The solvent-based modified fluorocarbon resin is prepared by modifying the fluorocarbon resin with (acryloxymethyl)phenylethyltrimethoxysilane; The modified silicon dioxide is prepared by modifying silicon dioxide with a silane coupling agent; The solvent-based modified fluorocarbon resin is prepared by the following steps: adding (acryloxymethyl)phenylethyltrimethoxysilane, fluorocarbon resin, deionized water and an organic solvent into a reactor, heating to 70-90° C., stirring evenly, adding an initiator, reacting for 6-8 hours and then cooling to obtain the solvent-based modified fluorocarbon resin; The modified silicon dioxide is prepared by the following steps: adding an organic solvent and silicon dioxide into a reactor, adding a silane coupling agent after ultrasonic dispersion, heating to 80-90° C., reacting at a constant temperature for 8-12 hours under a closed condition, cooling, centrifuging, purifying, and drying to obtain the modified silicon dioxide; The modified epoxy resin is prepared by the following steps: adding bisphenol F epoxy resin, phenolic resin and catalyst into a reactor, heating to 110-120° C. for reaction for 30-60 minutes, adding organic siloxane monomer with stirring, heating to 140-150° C. for reaction for 1-2 hours, cooling and filtering to obtain the modified epoxy resin.

2. The acid-, alkali-, heat-resistant and heavy-duty anticorrosive coating according to claim 1, characterized in that: The mass ratio of the (acryloyloxymethyl)phenylethyltrimethoxysilane to the fluorocarbon resin is 1:4-6; and the initiator is selected from one of dibutyltin dilaurate and dibutyltin diacetate.

3. The acid-, alkali-, heat-resistant and heavy-duty anticorrosive coating according to claim 1, characterized in that: The mass ratio of the silicon dioxide to the silane coupling agent is 3-5:1; the silicon dioxide is selected from a silane coupling agent with a specific surface area of ​​200-300m 2 / g of silicon dioxide powder; the silane coupling agent is selected from one of 3-aminopropyltriethoxysilane and N-2-aminoethyl-3-aminopropyltriethoxysilane.

4. The acid-, alkali-, temperature-resistant and heavy-duty anticorrosive coating according to claim 1, characterized in that: The mass ratio of the bisphenol F epoxy resin, the phenolic resin and the organosiloxane monomer is (1.2-1.5): (0.8-1): (0.3-0.5); the organosiloxane monomer is selected from one of vinyl triisopropoxy silane, octavinyl cyclotetrasiloxane or octamethyl cyclotetrasiloxane; and the catalyst is selected from one of triethylamine, tetraethylammonium bromide or triphenylphosphine.

5. The acid-, alkali-, heat-resistant and heavy-duty anticorrosive coating according to claim 1, characterized in that: The curing agent is selected from one of methyl ethyl ketone peroxide, m-phenylenediamine or diaminodiphenyl sulfone.

6. The acid-, alkali-, temperature-resistant, heavy-duty anticorrosive coating according to claim 1, characterized in that: Taking the total mass fraction as 100%, the mass percentage of each component is: Modified epoxy resin 15-20% Solvent-based modified fluorocarbon resin 45-60% Modified silica 8-12% Curing agent 3-5% The balance is propylene glycol methyl ether acetate.

7. The method for preparing the acid-, alkali-, heat-resistant and heavy-duty anticorrosive coating according to any one of claims 1 to 6, characterized in that: The following steps are involved: The modified epoxy resin, solvent-based modified fluorocarbon resin, modified silicon dioxide, curing agent and propylene glycol methyl ether acetate are weighed in proportion, mixed and dispersed evenly to obtain the acid-, alkali-, temperature-, and heavy-duty anticorrosive coating.

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