A coating for metal protection and a method for preparing the same

Abstract

The present disclosure relates to the technical field of paint, in particular to a paint for metal protection and a preparation method thereof; the paint comprises the following components in parts by weight: 25-35 parts by weight of modified rosin-based resin, 15-25 parts by weight of cyclohexanone, 5-10 parts by weight of diethyl phthalate, 5-10 parts by weight of borax, 1-5 parts by weight of modified alumina, 1-5 parts by weight of modified silicon oxide and 5-35 parts by weight of auxiliary.

Description

Technical Field

[0001] This disclosure relates to the field of coating technology, and in particular to a coating for metal protection and a method for preparing the same. Background Technology

[0002] Metallic materials are widely used in construction, transportation, national defense, and other fields. However, during use, metals are prone to chemical reactions with the surrounding environment, leading to corrosion. Corrosion is an increasingly serious problem, causing enormous waste of global resources every year. To solve this problem, there is an urgent need for a coating for metal protection.

[0003] Rosin is a biomass resource obtained from pine trees through processes such as distillation; while epoxy resin is widely used in aerospace, new energy vehicles, wind power generation, 5G communication, marine corrosion protection and other industrial fields and high-tech industries. In recent years, my country's consumption has been huge and increasing year by year; therefore, it is worth considering using rosin-based epoxy resin in coatings for the protection of metal materials. Summary of the Invention

[0004] This disclosure provides a coating for metal protection and a method for preparing the same, in order to address the shortcomings of related technologies.

[0005] According to a first aspect of the present disclosure, a coating for metal protection is provided, the coating comprising the following components in parts by weight:

[0006] 25-35 parts by weight of modified rosin-based resin, 15-25 parts by weight of cyclohexanone, 5-10 parts by weight of diethyl phthalate, 5-10 parts by weight of borax, 1-5 parts by weight of modified alumina, 1-5 parts by weight of modified silica, and 5-35 parts by weight of additives.

[0007] In one aspect of this disclosure, preferably, the coating comprises the following components in parts by weight:

[0008] 28-32 parts by weight of modified rosin-based resin, 20-25 parts by weight of cyclohexanone, 8-10 parts by weight of diethyl phthalate, 5-7 parts by weight of borax, 2-4 parts by weight of modified alumina, 2-4 parts by weight of modified silica, and 10-15 parts by weight of additives.

[0009] In one aspect of this disclosure, the modified alumina is alumina nanoparticles that have undergone lipophilic modification; the lipophilic modification process includes the following steps:

[0010] Step 1-a: Provide alumina nanoparticles and disperse the alumina nanoparticles in anhydrous ethanol;

[0011] Step 2-a: Add hexadecyltrimethoxysilane, water and glacial acetic acid sequentially to the anhydrous ethanol, and stir at room temperature for 2-3 hours to obtain the first mixed solution;

[0012] Step 3-a: Add E51 epoxy resin solution and acetone to the first mixed solution, stir for 0.5-1h to obtain the second mixed solution;

[0013] Step 4-a: The second mixed solution is sprayed onto the substrate using a spraying method, then left to stand for 2-3 hours, the product is collected, and after washing and drying, the oleophilic modified alumina nanoparticles are obtained.

[0014] In one aspect of this disclosure, the modified silica is oleophilic silica nanoparticles; the oleophilic modification process includes the following steps:

[0015] Step 1-b: Provide silica nanoparticles and disperse the silica nanoparticles in anhydrous ethanol;

[0016] Step 2-b: Add ammonia to the anhydrous ethanol while stirring, add trimethoxy(3-methoxypropyl)silane dropwise into the solution, then heat to 45℃-55℃ and continue stirring for 2-3 hours to obtain the third mixed solution;

[0017] Step 3-b: Cool the third mixed solution to room temperature, dissolve hexadecyl acrylate in anhydrous ethanol, add it to the third mixed solution, continue stirring for 1-2 hours, and obtain the lipophilic modified silica nanoparticles after filtration, washing and drying.

[0018] In one aspect of this disclosure, the modified rosin-based resin is prepared by the following steps:

[0019] Step 1-c: Add rosin-based ethylene glycol diglycidyl acrylate and methylphenyl dimethoxysilane to the reaction vessel, heat to 90℃-100℃, keep stirring, then add the catalyst, react for 4-5 hours, and then cool to 75℃-80℃.

[0020] Step 2-c: Add formaldehyde and tung oil to the cooled reaction vessel, continue the reaction for 3-4 hours, then cool to 40℃-50℃ and keep the temperature for 6-12 hours. Then collect the lower layer of orange-red transparent viscous liquid to obtain the modified rosin-based resin.

[0021] In one aspect of this disclosure, the additive includes at least one of an antifoaming agent, a dispersant, and a leveling agent.

[0022] In one aspect of this disclosure, preferably, the additives comprise a dispersant and a leveling agent.

[0023] In one aspect of this disclosure, the defoamer is selected from tributyl phosphate, defoamer Deqian 3100, or defoamer BYK088.

[0024] In one aspect of this disclosure, the dispersant is selected from polycarboxylate dispersant 5040 or sodium hexametaphosphate.

[0025] In one aspect of this disclosure, the leveling agent is selected from leveling agent BYK-333 or silicone leveling agent HY-5030.

[0026] In one aspect of this disclosure, the coating further comprises 2-8 parts by weight of compound D, said compound D having the following structural formula:

[0027]

[0028] R1 and R2 are each independently selected from hydrogen, halogen atom, nitro, amino, cyano, hydroxyl, carboxyl, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C2-C30 alkynyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C3-30 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted 3-30 membered heterocyclic group or substituted or unsubstituted 5-30 membered heteroaryl.

[0029] In one aspect of the embodiments of this disclosure, preferably, R1 and R2 are each independently selected from hydrogen, halogen atom, nitro, amino, cyano, hydroxyl, carboxyl, C1-C10 alkyl, C2-C10 alkenyl, C3-12 cycloalkyl or C6-C12 aryl.

[0030] In one aspect of this disclosure, the coating further comprises 2-8 parts by weight of compound D-1, said compound D-1 having the following structural formula:

[0031] According to a second aspect of the present disclosure, a method for preparing the aforementioned coating for metal protection is provided, the method comprising the following steps:

[0032] Step 1-d: Preparation of modified rosin-based resin;

[0033] Step 2-d: The modified rosin-based resin and diethyl phthalate are mixed by mechanical stirring;

[0034] Step 3-d: Prepare lipophilic modified alumina nanoparticles and lipophilic modified silica nanoparticles by adding borax, the prepared modified alumina, and modified silica into cyclohexanone and dispersing them thoroughly.

[0035] Step 5-d: Prepare compound D-1 and mix it with the auxiliary agent;

[0036] Step 6-d: Slowly mix the product obtained in step 3-d and the product obtained in step 2-d, and then add the product obtained in step 5-d to obtain the coating for metal protection.

[0037] In one aspect of this disclosure, step 5-d further includes the following steps:

[0038] Step 1-e: Using imidazole-2-carboxylic acid and 2-amino-2-(1H-imidazole-2-yl)ethanol-1-ol hydrochloride as raw materials, intermediate product 1 is obtained after condensation;

[0039] Step 2-e: React intermediate 1 with p-toluenesulfonyl chloride to obtain intermediate 2;

[0040]

[0041] Step 3-e: Intermediate 2 is reacted with N,N-diisopropylethylamine to give compound D-1;

[0042]

[0043] The technical solutions provided by the embodiments of this disclosure may include the following beneficial effects:

[0044] As can be seen from the above embodiments, this disclosure has prepared a high-performance coating for metal protection, which has good anti-corrosion effect.

[0045] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Detailed Implementation

[0046] The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with embodiments. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. The embodiments described herein are illustrative in nature and are used to provide a basic understanding of this application. The embodiments of this application should not be construed as limiting this application.

[0048] For the sake of brevity, this article only discloses a few specific numerical ranges. However, any lower limit can be combined with any upper limit to form an unspecified range; and any lower limit can be combined with other lower limits to form an unspecified range, just as any upper limit can be combined with any other upper limit to form an unspecified range. Furthermore, each individually disclosed point or single value can itself serve as a lower or upper limit and be combined with any other point or single value or with other lower or upper limits to form an unspecified range.

[0049] In this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0050] In this description, unless otherwise stated, "above" and "below" include the stated number.

[0051] Unless otherwise stated, the terms used in this disclosure have their common meanings as commonly understood by those skilled in the art. Unless otherwise stated, the values ​​of the parameters mentioned in this disclosure can be measured using various measurement methods commonly used in the art (e.g., they can be tested according to the methods given in the embodiments of this disclosure).

[0052] The term "about" is used to describe and indicate small variations. When used in conjunction with an event or situation, the term may refer to examples in which the event or situation occurred precisely or in examples in which the event or situation occurred very approximately. For example, when used in conjunction with numerical values, the term may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. Additionally, quantities, ratios, and other numerical values ​​are sometimes presented in range format herein. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly to include not only numerical values ​​explicitly specified as range limits but also all individual numerical values ​​or subranges covered within the range, as if each numerical value and subrange were explicitly specified.

[0053] The list of items connected by the terms "at least one of," "at least one of," "at least one of," or other similar terms can mean any combination of the listed items. For example, if items A and B are listed, then the phrase "at least one of A and B" means only A; only B; or A and B. In another instance, if items A, B, and C are listed, then the phrase "at least one of A, B, and C" means only A; or only B; only C; A and B (excluding C); A and C (excluding B); B and C (excluding A); or all of A, B, and C. Item A may contain a single component or multiple components. Item B may contain a single component or multiple components. Item C may contain a single component or multiple components.

[0054] In this disclosure, the term "alkyl" refers to an aliphatic hydrocarbon group, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, that link a linear alkyl chain. "Lower alkyl" refers to a group containing about 1 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0055] In this disclosure, the term "alkenyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon double bond, which can be straight-chain or branched. Branched refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkenyl chain. "Lower alkenyl" refers to a group containing about 2 to about 6 carbon atoms in the chain, which can be straight-chain or branched.

[0056] In this disclosure, the term "alkynyl" refers to an aliphatic hydrocarbon group containing at least one carbon-carbon triple bond, which can be straight-chain or branched. Branching refers to one or more lower alkyl groups, such as methyl, ethyl, or propyl, attached to a linear alkynyl chain. "Lower alkynyl" refers to a chain containing about 2 to about 6 carbon atoms, which can be straight-chain or branched. Non-limiting examples of alkynyl groups include ethynyl, propynyl, 2-butynyl, 3-methylbutynyl, n-pentynyl, and decynyl.

[0057] In this disclosure, the term "aryl" refers to an aromatic monocyclic or polycyclic ring system. An aryl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. Non-limiting examples of suitable aryl groups include phenyl and naphthyl.

[0058] In this disclosure, the term "heteroaryl" refers to an aromatic monocyclic or polycyclic ring system, wherein one or more ring atoms are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination, and preferably a heteroaryl contains about 5 to about 6 ring atoms. A "heteroaryl" may optionally be substituted by one or more "cyclic substituents," which may be the same or different, as defined herein. The prefixes azido, oxa, or thiado preceding the name of a heteroaryl root indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The nitrogen atom of a heteroaryl may optionally be oxidized to the corresponding N-oxide. Suitable, non-limiting examples of heteroaryl groups include pyridyl, pyrazinyl, furanyl, phenylthio, pyrimidinyl, isoxazolyl, isothiazolyl, oxazolyl, thiazolyl, pyrazolyl, furazanyl, pyrroleyl, pyrazolyl, triazolyl, 1,2,4-thiadiazolyl, pyrazinyl, pyridazinyl, quinoxalinyl, 2,3-diazanaphthyl, imidazo[1,2-a]pyridyl, imidazo[2,1-b]thiazolyl, benzofurazanyl, indoleyl, azaindoleyl, benzimidazolyl, benzothiopheneyl, quinolinyl, imidazolyl, thienopyridyl, quinazolinyl, thienopyrimidinyl, pyrrolopyridyl, imidazopyridyl, isoquinolinyl, benzoazaindoleyl, 1,2,4-triazinyl, benzothiazolyl, etc.

[0059] In this disclosure, the term "amino" refers to the -NR′R′′ group. The amino group may optionally be substituted. In an unsubstituted amino group, R′ and R′′ are hydrogen. In a substituted amino group, R′ and R′′ may each independently be, but not limited to, hydrogen, alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, alkylcycloalkyl, alkylheterocycloalkyl, alkoxy, sulfonyl, alkenyl, alkanoyl, aryl, arylalkyl, or heteroaryl, provided that R′ and R′′ are not both hydrogen. In a substituted amino group, R′ and R′′ may cyclize to form a cyclic amino group, such as pyrrolidinyl or piperidinyl. Such cyclic amino groups may incorporate other heteroatoms, for example, to form piperazine or morpholine groups. Such cyclic amino groups may optionally be substituted, for example, by an amino, hydroxyl, or oxo group.

[0060] In this disclosure, the term "alkoxy" refers to -O-alkyl. Alkoxy can refer to a straight-chain, branched, or cyclic, saturated or unsaturated oxy-hydrocarbon chain, including, for example, methoxy, ethoxy, propoxy, isopropoxy, butoxy, tert-butoxy, and pentoxy. Alkoxy may optionally be substituted by one or more alkoxy substituents ("substituted alkoxy").

[0061] In this disclosure, the term "cycloalkyl" refers to a non-aromatic mono- or polycyclic ring system, preferably containing about 5 to about 7 ring atoms. The cycloalkyl group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined above. Suitable monocyclic cycloalkyl groups, without limitation, include cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl, etc. Suitable polycyclic cycloalkyl groups, without limitation, include 1-decahydronaphthyl, norcamphenyl, adamantyl, etc. In this disclosure, the term "cycloalkoxy" refers to a group in which one or more carbon atoms in the mono- or polycyclic ring system of the "cycloalkyl" group are substituted with oxygen atoms.

[0062] In this disclosure, the term "heterocyclic group" refers to a non-aromatic saturated monocyclic or polycyclic ring system, wherein one or more ring atoms in the ring system are elements other than carbon, such as nitrogen, oxygen, or sulfur, either individually or in combination. Adjacent oxygen and / or sulfur atoms are absent in the ring system, and preferred heterocycles contain about 5 to about 6 ring atoms. The prefixes aza, oxa, or thioa preceding the name of the heterocyclic group indicate that at least one nitrogen, oxygen, or sulfur atom is present as a ring atom, respectively. The heterocyclic group may optionally be substituted with one or more "cyclic substituents," which may be the same or different, as defined herein. The nitrogen or sulfur atom of the heterocyclic group may optionally be oxidized to the corresponding N-oxide, S-oxide, or S,S-dioxide. Non-limiting examples of suitable monocyclic heterocyclic rings include piperidinyl, pyrrolyl, piperazine, morpholinyl, thiomorpholinyl, thiazolyl, 1,3-dioxolanecycloyl, 1,4-dioxacyclohexyl, tetrahydrofuranyl, tetrahydrophenylthio, tetrahydrothiopyranyl, etc.

[0063] The present disclosure will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present disclosure are obtained through conventional commercial means. Unless otherwise specified, all contents mentioned below are mass contents. Unless otherwise specified, it is understood that the process is carried out at room temperature.

[0064] Example: Example 1: Example 1 includes the following steps:

[0065] 1. Preparation of lipophilic modified alumina nanoparticles: 25g of alumina nanoparticles (D90 particle size of 100nm, commercially available) were provided and dispersed in 250mL of anhydrous ethanol. 20mL of hexadecyltrimethoxysilane, 40mL of distilled water, and 10mL of glacial acetic acid were added sequentially to the anhydrous ethanol, and the mixture was stirred at room temperature for 3h to obtain a first mixed solution. 25mL of E51 epoxy resin solution and 50mL of acetone were added to the first mixed solution, and the mixture was stirred for 1h to obtain a second mixed solution. The second mixed solution was sprayed onto a substrate (glass plate) using a spraying method, with the distance between the spray gun and the glass plate surface being 60cm and the spraying pressure being 0.3MPa. The mixture was then allowed to stand for 3h, and the product was collected, washed, and dried to obtain lipophilic modified alumina nanoparticles.

[0066] 2. Preparation of lipophilic modified silica nanoparticles: 25g of silica nanoparticles (D90 particle size of 2μm, commercially available) were provided. The silica nanoparticles were dispersed in 250mL of anhydrous ethanol. 15g of ammonia water was added to the anhydrous ethanol and stirred. 25g of trimethoxy(3-methoxypropyl)silane was placed in a constant pressure funnel and added dropwise to the solution over 1h. The temperature was then raised to 50℃ and stirred for 2h to obtain a third mixed solution. The third mixed solution was then cooled to room temperature. 20g of hexadecyl acrylate was dissolved in anhydrous ethanol and added to the third mixed solution. The mixture was stirred for 2h. After filtration, washing, and drying, lipophilic modified silica nanoparticles were obtained.

[0067] 3. Preparation of modified rosin-based resin: 40g of rosin-based ethylene glycol diglycidyl acrylate (rosin-based ethylene glycol diglycidyl acrylate is prepared by the following steps: adding rosin-acrylic acid and triethylamine to a four-necked flask equipped with a stirrer, condenser, dropping funnel and nitrogen delivery tube, heating to melt the rosin-acrylic acid, adding butylene glycol diglycidyl ether dropwise, and reacting for 2 hours) and 15g of methylphenyl dimethoxysilane were added to a reaction vessel, heated to 90℃, and stirred. Then 0.2g of tetraisopropyl titanate catalyst was added, and the reaction was carried out for 4 hours. After cooling, the temperature was lowered to 80℃. 5g of formaldehyde and 7.5g of tung oil were added to the cooled reaction vessel, and the reaction was continued for 4 hours. Then the temperature was lowered to 50℃ and kept at that temperature for 10 hours. The lower layer of orange-red transparent viscous liquid was collected to obtain the modified rosin-based resin.

[0068] 4. Preparation of compound D-1: 30 mmol of imidazole-2-carboxylic acid was dissolved in an appropriate amount of DMF and transferred to a single-necked flask. 45 mmol of HATU and 30 mmol of 2-amino-2-(1H-imidazol-2-yl)ethanol-1-ol hydrochloride were added, followed by dropwise addition of DIPEA (60 mmol) at room temperature. After the addition was complete, the reaction was allowed to proceed at room temperature for 2 hours. After the reaction was complete, the solvent was removed by rotary evaporation, and the product was purified with silica gel (ethyl acetate / petroleum ether = 1 / 4) to give intermediate 1.

[0069] Intermediate 1 was dissolved in an appropriate amount of tetrahydrofuran and then transferred to a single-necked flask. The mixture was stirred at approximately 0°C for 5 minutes. Then, p-toluenesulfonyl chloride (32 mmol) was slowly added dropwise to the reaction system. After the addition was complete, the mixture was allowed to rise to room temperature and react for 6 hours. The reaction was confirmed to be complete by LC-MS. The solvent was removed by rotary evaporation, and the mixture was extracted three times with ethyl acetate and water. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation to obtain intermediate 2, which was used directly in the next step.

[0070] Intermediate 2 was dissolved in an appropriate amount of tetrahydrofuran, then transferred to a single-necked flask, and DIPEA (71 mmol) was added. The mixture was heated to 75°C and reacted for 10 hours. The reaction mixture was monitored by LC-MS to ensure complete reaction of the starting material. The solvent was removed by rotary evaporation of the reaction solution, and the mixture was extracted three times with ethyl acetate and water. The organic phases were combined, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation. The mixture was then purified with silica gel (ethyl acetate / petroleum ether = 1 / 3) to give compound D-1. 1 H NMR: δ 4.51-4.67 (3H, 4.59 (dd, J = 13.5, 7.4Hz), 4.60 (dd, J = 7.8, 6.9 Hz), 7.21 (1H, d, J = 3.3 Hz), 7.33-7.46 (2H,7.39 (d, J = 4.3 Hz), 7.41 (d, J = 3.3 Hz), 7.62 (1H, d, J = 4.3 Hz). 13 CNMR: δ 56.8 (1C, s), 69.7 (1C, s), 119.7-119.8 (2C, 119.7 (s), 119.7 (s)), 122.0-122.1 (2C, 122.0 (s), 122.0 (s)), 146.5 (1C, s), 153.1 (1C, s), 155.2(1C, s).

[0071] 5. Preparation of coating: Weigh 30 parts by weight of modified rosin-based resin, 25 parts by weight of cyclohexanone, 10 parts by weight of diethyl phthalate, 6 parts by weight of borax, 3 parts by weight of modified alumina, 3 parts by weight of modified silica, 4 parts by weight of compound D-1, 7 parts by weight of sodium hexametaphosphate dispersant, and 7 parts by weight of leveling agent BYK-333; mix the modified rosin-based resin and diethyl phthalate by mechanical stirring; add borax, modified alumina, and modified silica to cyclohexanone and disperse them thoroughly; mix the two slowly; then mix and add compound D-1, sodium hexametaphosphate dispersant, and leveling agent BYK-333, and disperse thoroughly to obtain the coating of Example 1.

[0072] Comparative Example 1: The steps of Comparative Example 1 are the same as those of Example 1, except that Comparative Example 1 uses an equal mass of acrylic rosin (commercially available) instead of the modified rosin-based resin prepared in Example 1.

[0073] Comparative Example 2: The steps of Comparative Example 2 are the same as those of Example 1, except that Comparative Example 2 uses an equal mass of rosin-based ethylene glycol diglycidyl acrylate (rosin-based ethylene glycol diglycidyl acrylate is prepared by the following steps: adding rosin acrylic acid and triethylamine into a four-necked flask equipped with a stirrer, condenser, dropping funnel and nitrogen delivery tube, heating to melt the rosin acrylic acid, adding butylene glycol diglycidyl ether dropwise, and reacting for 2 hours to obtain the modified rosin-based resin prepared in Example 1).

[0074] Comparative Example 3: The steps of Comparative Example 3 are the same as those of Example 1, except that Comparative Example 3 uses an equal mass of rosin glycerol ester instead of the modified rosin-based resin prepared in Example 1.

[0075] Comparative Example 4: The steps for Comparative Example 4 are the same as those for Example 1, except that benzotriazole is used instead of compound D-1 prepared in Example 1.

[0076] Comparative Example 5: The steps of Comparative Example 5 are the same as those of Example 1, except that intermediate product 1 is used in Comparative Example 5 instead of compound D-1 prepared in Example 1.

[0077] Corrosion resistance test:

[0078] The corrosion resistance of the coatings in Example 1 and Comparative Examples 1-4 was tested using the following method: Samples from Example 1 and Comparative Examples 1-4 were coated onto 50mm × 50mm × 2mm stainless steel test pieces, with a film thickness of approximately 50μm. After coating, the samples were cured at 180°C for 30 minutes. The cured stainless steel test pieces were then placed in a salt spray test chamber and tested according to GB / T1771-2007 "Determination of Resistance to Neutral Salt Spray of Paints and Varnishes," with appropriate parameter modifications to conform to this invention. The test temperature was increased to 50°C, and the salt spray concentration was controlled at 5%. The test duration was 500 hours, with corrosion observed every 100 hours. After the test, the corrosion of the test pieces was evaluated according to ASTM D714, observing for rust, bubbles, and peeling on the coating surface. The experimental results showed:

[0079] The sample treated in Example 1 showed no rust and almost no blistering;

[0080] Comparative Example 1: Slight corrosion, localized cracks and peeling of the coating, and low bubble density;

[0081] Comparative Example 2: Slight corrosion, localized cracks and peeling of the coating, and low bubble density;

[0082] Comparative Example 3 showed mild corrosion, localized cracks and peeling of the coating, and low bubble density.

[0083] Comparative Example 4: Moderate corrosion, coating cracks and peeling, and moderate bubble density;

[0084] Comparative Example 5: Severe corrosion, with cracks and peeling of the coating and a high density of air bubbles.

[0085] Corrosion resistance tests demonstrated that: 1) the rosin material modified by this application has better corrosion resistance than other rosin materials; 2) the corrosion resistance principle of compound D-1 prepared by this application is similar to that of benzotriazole used in the prior art: that is, the nitrogen atoms in the molecules have lone pairs of electrons, which can form stable coordinate bonds with metal ions on the metal surface, thereby causing chemical adsorption on the metal surface. This adsorption allows compound D-1 or benzotriazole to form a dense protective film on the metal surface. The thickness of this film is usually less than 50 angstroms, possibly a monolayer, which can effectively isolate the metal from the external environment and prevent the metal from being oxidized and corroded. Furthermore, the nitrogen atoms in the molecule of compound D-1 prepared by this application have a higher density of lone pairs of electrons, resulting in better coordination and thus better corrosion resistance than benzotriazole. This is also the reason why the corrosion resistance of Example 1 is stronger than that of Comparative Example 4. However, Comparative Example 5, which directly uses intermediate product 1, cannot form a planar structure like that of Example 1, making it difficult to form a monolayer protective film, and therefore has worse corrosion resistance.

[0086] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the disclosure herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein.

Claims

1. A coating for the protection of metals, characterized in that The coating comprises the following components by weight: 25-35 parts by weight of modified rosin-based resin, 15-25 parts by weight of cyclohexanone, 5-10 parts by weight of diethyl phthalate, 5-10 parts by weight of borax, 1-5 parts by weight of modified alumina, 1-5 parts by weight of modified silica, and 5-35 parts by weight of an auxiliary agent; The modified alumina is an alumina nanoparticle modified by lipophilization; The modified silica is a silica nanoparticle modified by lipophilization; The modified rosin-based resin is prepared by the following steps: Step 1-c: Put rosin-based glycidol acrylate and methylphenyl dimethoxysilane into a reaction container, heat to 90-100°C, keep stirring, then add catalyst, after 4-5h reaction, cool to 75-80°C; Step 2-c: Add formaldehyde and tung oil to the cooled reaction container, continue to react for 3-4h, then cool to 40-50°C and keep the temperature for 6-12h, then collect the orange-red transparent viscous liquid in the lower layer to obtain the modified rosin-based resin; The coating further comprises 2-8 parts by weight of compound D-1, which has the following structural formula: 。 2. The coating for metal protection according to claim 1, characterized in that, The modified alumina is an alumina nanoparticle modified by lipophilization; the process of lipophilic modification includes the following steps: Step 1-a: Provide alumina nanoparticles, disperse the alumina nanoparticles in anhydrous ethanol; Step 2-a: Add hexadecyl trimethoxysilane, water and glacial acetic acid into the anhydrous ethanol in sequence, stir for 2-3h at room temperature to obtain a first mixed solution; Step 3-a: Add E51 epoxy resin solution and acetone into the first mixed solution, stir for 0.5-1h to obtain a second mixed solution; Step 4-a: Spray the second mixed solution onto a substrate by spraying method, then stand for 2-3h, collect the product, wash and dry to obtain the alumina nanoparticle modified by lipophilization.

3. The coating for metal protection according to claim 1, characterized in that, The modified silica is a silica nanoparticle modified by lipophilization; the process of lipophilic modification includes the following steps: Step 1-b: Provide silica nanoparticles, disperse the silica nanoparticles in anhydrous ethanol; Step 2-b: Add ammonia water into the anhydrous ethanol, keep stirring, drop trimethoxy(3-methoxypropyl)silane into the solution, then heat to 45-55°C, continue to stir for 2-3h; obtain a third mixed solution; Step 3-b: Cool the third mixed solution to room temperature, dissolve hexadecyl acrylate in anhydrous ethanol, add into the third mixed solution, continue to stir for 1-2h, filter, wash and dry to obtain the silica nanoparticle modified by lipophilization.

4. The coating for metal protection according to claim 1, characterized in that, The auxiliary agent comprises at least one of defoaming agent, dispersing agent and leveling agent; wherein: The defoaming agent is selected from tributyl phosphate, defoaming agent Decon 3100 or defoaming agent BYK088; The dispersing agent is selected from polycarboxylate dispersant 5040 or sodium hexametaphosphate; The leveling agent is selected from leveling agent BYK-333 or silicone leveling agent HY-5030.

5. A process for the production of a coating material for the protection of metals as defined in any of claims 1 to 3, characterized in that The method comprises the following steps: Step 1-d: Preparation of modified rosin-based resin; Step 2-d: Mixing the modified rosin-based resin with diethyl phthalate after mechanical stirring; Step 3-d: Preparation of oleophilic modified alumina nanoparticles and oleophilic modified silica nanoparticles, adding borax, modified alumina, modified silica prepared to cyclohexanone and dispersing thoroughly; Step 5-d: Preparation of compound D-1 and mixing with adjuvant; Step 6-d: Slowly mixing the product obtained in step 3-d and the product obtained in step 2-d, then adding the product obtained in step 5-d, to obtain the coating for metal protection; Step 5-d includes the following steps: Step 1-e: Using imidazole-2-carboxylic acid and 2-amino-2-(1H-imidazol-2-yl)ethan-1-ol hydrochloride as raw materials, after condensation, an intermediate product 1 is obtained. ; Step 2-e: reaction of intermediate 1 with p-toluenesulfonyl chloride to give intermediate 2; ; Step 3-e: reacting intermediate 2 with N,N-diisopropylethylamine to give compound D-1; 。

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