Anti-rust black coating for tire screws and nuts and preparation method of anti-rust black coating

Abstract

The invention relates to the technical field of coatings, and discloses an anti-rust black coating for tire screws and nuts and a preparation method thereof.Polyphosphoric acid, cardanol modified polyurethane, ferrocene modified pyrazine, black pigment and talcum powder are added into a stirrer and stirred, and the anti-rust black coating for the tire screws and nuts is obtained after stirring is finished. Pyrazine groups contained in ferrocene modified pyrazine and cardanol modified polyurethane have the antirust capability; long-chain alkane contained in cardanol in cardanol modified polyurethane has good film-forming property, a protective layer can be formed, an antirust effect is achieved, in the stirring process, epoxy groups in ferrocene modified pyrazine and hydroxyl groups in cardanol modified polyurethane are subjected to ring-opening reaction, the compatibility between the epoxy groups and the hydroxyl groups is improved, and the antirust property of the cardanol modified polyurethane is improved. And cardanol long chains in the ferrocene modified pyrazine and the cardanol modified polyurethane can be intertwined to form a cross-linked network, so that the mechanical properties between the ferrocene modified pyrazine and the cardanol modified polyurethane are improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to an anti-rust black coating for tire screw nuts and a preparation method thereof. Background Art

[0002] When tire screws and nuts are placed outdoors for a long time, they will come into contact with oxygen, water vapor, bacteria and other substances in the air, which will cause corrosion and rust on their surfaces, thus affecting their normal use. Therefore, how to avoid this phenomenon is the key to solving the problem. For example, patent CN112608634A discloses a nano anti-corrosion and anti-rust coating. The invented nano anti-corrosion and anti-rust coating can withstand salt spray for 750 hours through the mutual cooperation between the components, but its tensile resistance effect is not improved. Summary of the invention

[0003] 1. Technical issues to be resolved In view of the deficiencies in the prior art, the present invention provides an anti-rust black coating for tire screw nuts and a preparation method thereof, which has good anti-rust and tensile properties.

[0004] (II) Technical solution To achieve the above-mentioned purpose, the present invention provides the following technical scheme: a rust-proof black coating for tire screw nuts, comprising the following components by weight: 3-5 parts by weight of polyphosphoric acid, 4-7 parts by weight of cardanol-modified polyurethane, 2-6 parts by weight of silicon-modified pyrazine, 2-4 parts by weight of black pigment, and 1-3 parts by weight of talc.

[0005] Preferably, the preparation method of the cardanol-modified polyurethane is: (1) Add 2,2-di(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, stir evenly, then continue to add 3-5 mol / L sodium hydroxide aqueous solution, react at 65-75° C. for 3-6 hours, and after the reaction is completed, neutralize, concentrate, filter, wash and dry to obtain dihydroxy cardanol; (2) adding dihydroxy cardanol and 2-hydroxy-5-chloropyrazine into N,N-dimethylformamide solvent, stirring to dissolve, reacting at 75-90° C. for 5-8 hours, and then distilling under reduced pressure, washing and drying to obtain a cardanol chain extender; (3) Adding aminopropyl-terminated polydimethylsiloxane and isophorone diisocyanate to tetrahydrofuran solvent, reacting at 40-50° C. for 3-5 hours, then adding cardanol chain extender, reacting at 45-60° C. for 8-10 hours, filtering and washing after reaction, to obtain cardanol-modified polyurethane.

[0006] Preferably, the mass ratio of 2,2-bis(bromomethyl)-1,3-propanediol to cardanol in (1) is 1:1.2-1.6.

[0007] Preferably, the mass ratio of dihydroxycardanol to 2-hydroxy-5-chloropyrazine in (2) is 0.8-1.1:1.

[0008] Preferably, the mass ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate and cardanol chain extender in (3) is 1:0.9-1.3:0.01-0.03.

[0009] Preferably, the preparation method of the silicon-modified pyrazine is: S1. Add 16-18 parts by weight of cardanol chain extender and 20-26 parts by weight of acrylic acid to N,N-dimethylformamide solvent, stir to dissolve, then continue to add p-toluenesulfonic acid catalyst, react at 90-110 ° C for 10-12h, and then rotary distill, wash with acetone, and dry to obtain olefinated pyrazine; S2. Add 10-14 parts by weight of alkenyl pyrazine and 12-16 parts by weight of hexamethyldisilazane to acetonitrile solvent, stir and disperse, continue to add chloroplatinic acid catalyst, react at 55-80 ° C for 4-6h, and then distill under reduced pressure, wash and dry to obtain tertiary amino pyrazine; S3. Add 7-10 parts by weight of tertiary amino pyrazine and 8-15 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, raise the temperature to 70-85°C for reaction, the reaction time is 4-7h, and then concentrate under reduced pressure and wash with deionized water to obtain silicon-modified pyrazine.

[0010] Preferably, the method for preparing the anti-rust black coating for tire screw nuts is: adding polyphosphoric acid, cardanol-modified polyurethane, ferrocene-modified pyrazine, black pigment, and talcum powder into a stirrer, stirring for 8-14 minutes, and obtaining the anti-rust black coating for tire screw nuts after stirring.

[0011] 3. Beneficial technical effects The invention adds polyphosphoric acid, cardanol modified polyurethane, ferrocene modified pyrazine, black pigment and talcum powder into a stirrer and stirs the mixture to obtain a rust-proof black coating for tire screw nuts.

[0012] The pyrazine groups contained in ferrocene-modified pyrazine and cardanol-modified polyurethanes have anti-rust ability; the long-chain alkanes contained in cardanol in cardanol-modified polyurethanes have good film-forming properties and can form a protective layer to prevent rust. The siloxane therein also has good anti-rust ability. The anti-rust mechanism of siloxane is mainly to form a protective film on the metal surface to block moisture and oxygen from contacting the metal, thereby slowing down or preventing the corrosion process; the ferrocene groups in ferrocene-modified pyrazine also have good anti-rust effects; during the stirring process, the epoxy groups in ferrocene-modified pyrazine and the hydroxyl groups in cardanol-modified polyurethane undergo a ring-opening reaction, which improves the compatibility between each other, and the long chains of cardanol in ferrocene-modified pyrazine and cardanol-modified polyurethanes will entangle with each other to form a cross-linked network, which increases the mechanical properties between each other. DETAILED DESCRIPTION

[0013] The molecular weight of aminopropyl terminated polydimethylsiloxane is 2500.

[0014] Example 1 (1) Add 2,2-bis(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, wherein the mass ratio of 2,2-bis(bromomethyl)-1,3-propylene glycol to cardanol is 1:1.2, stir evenly, then continue to add 3 mol / L sodium hydroxide aqueous solution, react at 65°C for 3 hours, and after the reaction is completed, neutralize, concentrate, filter, wash and dry to obtain dihydroxy cardanol; (2) adding dihydroxy cardanol and 2-hydroxy-5-chloropyrazine into N,N-dimethylformamide solvent, wherein the mass ratio of dihydroxy cardanol to 2-hydroxy-5-chloropyrazine is 0.8:1, stirring and dissolving, reacting at 75°C for 5 hours, and then distilling under reduced pressure, washing and drying to obtain a cardanol chain extender; (3) Adding aminopropyl-terminated polydimethylsiloxane and isophorone diisocyanate to tetrahydrofuran solvent, reacting at 40°C for 3 hours, and then adding cardanol chain extender, wherein the mass ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate and cardanol chain extender is 1:0.9:0.01, reacting at 45°C for 8 hours, filtering and washing after completion, to obtain cardanol-modified polyurethane; (4) Add 16 parts by weight of cardanol chain extender and 20 parts by weight of acrylic acid to N,N-dimethylformamide solvent, stir to dissolve, then continue to add p-toluenesulfonic acid catalyst, react at 90° C. for 10 hours, and then perform rotary distillation, wash with acetone, and dry to obtain olefinated pyrazine; (5) Add 10 parts by weight of olefinated pyrazine and 12 parts by weight of hexamethyldisilazane to acetonitrile solvent, stir and disperse, continue to add chloroplatinic acid catalyst, react at 55° C. for 4 hours, and then distill under reduced pressure, wash and dry to obtain tertiary amino pyrazine; (6) Add 7 parts by weight of tertiary amino pyrazine and 8 parts by weight of epichlorohydrin into N,N-dimethylformamide solvent, heat to 70°C for reaction, the reaction time is 4 hours, and then concentrate under reduced pressure and wash with deionized water to obtain silicon-modified pyrazine; (7) Add 3 parts by weight of polyphosphoric acid, 4 parts by weight of cardanol-modified polyurethane, 2 parts by weight of silicon-modified pyrazine, 2 parts by weight of black pigment, and 1 part by weight of talc into a blender and stir for 8 minutes to obtain a rust-proof black coating for tire screw nuts.

[0015] Example 2 (1) Add 2,2-bis(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, wherein the mass ratio of 2,2-bis(bromomethyl)-1,3-propylene glycol to cardanol is 1:1.6, stir evenly, then continue to add 5 mol / L sodium hydroxide aqueous solution, react at 75°C for 6 hours, and after the reaction is completed, neutralize, concentrate, filter, wash and dry to obtain dihydroxy cardanol; (2) adding dihydroxy cardanol and 2-hydroxy-5-chloropyrazine into N,N-dimethylformamide solvent, wherein the mass ratio of dihydroxy cardanol to 2-hydroxy-5-chloropyrazine is 1.1:1, stirring and dissolving, reacting at 90° C. for 8 h, and then distilling under reduced pressure, washing and drying to obtain a cardanol chain extender; (3) Adding aminopropyl-terminated polydimethylsiloxane and isophorone diisocyanate to tetrahydrofuran solvent, reacting at 50° C. for 5 h, and then adding cardanol chain extender thereto, wherein the mass ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate, and cardanol chain extender is 1:1.3:0.03, reacting at 60° C. for 10 h, filtering after completion, washing, and obtaining cardanol-modified polyurethane; (4) Add 18 parts by weight of cardanol chain extender and 26 parts by weight of acrylic acid to N,N-dimethylformamide solvent, stir to dissolve, then continue to add p-toluenesulfonic acid catalyst, react at 110° C. for 12 hours, and then perform rotary distillation, wash with acetone, and dry to obtain olefinated pyrazine; (5) Add 14 parts by weight of olefinated pyrazine and 16 parts by weight of hexamethyldisilazane to acetonitrile solvent, stir and disperse, continue to add chloroplatinic acid catalyst, react at 80° C. for 6 hours, and then distill under reduced pressure, wash and dry to obtain tertiary amino pyrazine; (6) Add 10 parts by weight of tertiary amino pyrazine and 15 parts by weight of epichlorohydrin into N,N-dimethylformamide solvent, heat to 85°C for reaction, the reaction time is 7 hours, and then concentrate under reduced pressure and wash with deionized water to obtain silicon-modified pyrazine; (7) Add 5 parts by weight of polyphosphoric acid, 7 parts by weight of cardanol-modified polyurethane, 6 parts by weight of silicon-modified pyrazine, 4 parts by weight of black pigment, and 3 parts by weight of talc into a blender and stir for 14 minutes to obtain a rust-proof black coating for tire screw nuts.

[0016] Example 3 (1) Add 2,2-bis(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, wherein the mass ratio of 2,2-bis(bromomethyl)-1,3-propylene glycol to cardanol is 1:1.4, stir evenly, then continue to add 4 mol / L sodium hydroxide aqueous solution, react at 70°C for 4.5 hours, and after the reaction is completed, neutralize, concentrate, filter, wash and dry to obtain dihydroxy cardanol; (2) adding dihydroxy cardanol and 2-hydroxy-5-chloropyrazine into N,N-dimethylformamide solvent, wherein the mass ratio of dihydroxy cardanol to 2-hydroxy-5-chloropyrazine is 0.9:1, stirring and dissolving, reacting at 82°C for 6.5h, and then distilling under reduced pressure, washing and drying to obtain a cardanol chain extender; (3) Adding aminopropyl-terminated polydimethylsiloxane and isophorone diisocyanate to tetrahydrofuran solvent, reacting at 45° C. for 4 hours, and then adding cardanol chain extender, wherein the mass ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate, and cardanol chain extender is 1:1.1:0.02, reacting at 52° C. for 9 hours, filtering after completion, washing, and obtaining cardanol-modified polyurethane; (4) Add 17 parts by weight of cardanol chain extender and 23 parts by weight of acrylic acid to N,N-dimethylformamide solvent, stir to dissolve, then continue to add p-toluenesulfonic acid catalyst, react at 100° C. for 11 hours, and then perform rotary distillation, wash with acetone, and dry to obtain olefinated pyrazine; (5) Add 12 parts by weight of olefinated pyrazine and 14 parts by weight of hexamethyldisilazane to acetonitrile solvent, stir and disperse, continue to add chloroplatinic acid catalyst, react at 67° C. for 5 h, and then distill under reduced pressure, wash and dry to obtain tertiary amino pyrazine; (6) Add 8.5 parts by weight of tertiary amino pyrazine and 11.5 parts by weight of epichlorohydrin into N,N-dimethylformamide solvent, heat to 80°C for reaction, the reaction time is 5.5 hours, and then concentrate under reduced pressure and wash with deionized water to obtain silicon-modified pyrazine; (7) 4 parts by weight of polyphosphoric acid, 5.5 parts by weight of cardanol-modified polyurethane, 4 parts by weight of silicon-modified pyrazine, 3 parts by weight of black pigment, and 2 parts by weight of talc were added into a blender and stirred for 11 minutes to obtain a rust-proof black coating for tire screw nuts.

[0017] Comparative Example 1 (1) 4 parts by weight of polyphosphoric acid, 4 parts by weight of silicon-modified pyrazine, 3 parts by weight of black pigment, and 2 parts by weight of talc were added into a stirrer and stirred for 11 minutes to obtain a rust-proof black coating for tire screw nuts.

[0018] Comparative Example 2 (1) 4 parts by weight of polyphosphoric acid, 5.5 parts by weight of cardanol-modified polyurethane, 3 parts by weight of black pigment, and 2 parts by weight of talc were added into a blender and stirred for 11 minutes to obtain a rust-proof black coating for tire screw nuts.

[0019] Salt spray test After coating the metal surface with the anti-rust black coating of the tire screw nuts of Example 1-3 and Comparative Example 1-2, prepare a 5% NaCI solution with a PH value of 6.5-7.2, control the spray volume at 2 ml / 80 cm2·h for rapid spraying, and control the temperature at 35°C. The test results are shown in Table 1.

[0020] Table 1: Salt spray test.

[0021] It can be seen from Table 1 that Examples 1-3 of the present invention have a smaller corrosion area than Comparative Examples 1-2, indicating that the anti-rust effect is better.

[0022] The tensile properties of the coating were tested according to GB / T1040.1-2018 standard, and the test results are shown in Table 2.

[0023] It can be seen from Table 2 that Examples 1-3 of the present invention have better tensile properties than Comparative Examples 1-2.

[0024] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A rust-proof black coating for tire screw nuts, characterized in that: The invention comprises the following components by weight: 3-5 parts by weight of polyphosphoric acid, 4-7 parts by weight of cardanol-modified polyurethane, 2-6 parts by weight of silicon-modified pyrazine, 2-4 parts by weight of black pigment and 1-3 parts by weight of talc.

2. The rust-proof black coating for tire screw nuts according to claim 1, characterized in that: The preparation method of the cardanol modified polyurethane is: (1) Add 2,2-di(bromomethyl)-1,3-propylene glycol and cardanol to an acetone solvent, stir evenly, then continue to add 3-5 mol / L sodium hydroxide aqueous solution, react at 65-75° C. for 3-6 hours, and after the reaction is completed, neutralize, concentrate, filter, wash and dry to obtain dihydroxy cardanol; (2) adding dihydroxy cardanol and 2-hydroxy-5-chloropyrazine into N,N-dimethylformamide solvent, stirring to dissolve, reacting at 75-90° C. for 5-8 hours, and then distilling under reduced pressure, washing and drying to obtain a cardanol chain extender; (3) Adding aminopropyl-terminated polydimethylsiloxane and isophorone diisocyanate to tetrahydrofuran solvent, reacting at 40-50° C. for 3-5 hours, then adding cardanol chain extender, reacting at 45-60° C. for 8-10 hours, filtering and washing after reaction, to obtain cardanol-modified polyurethane.

3. The rust-proof black coating for tire screw nuts according to claim 2, characterized in that: The mass ratio of 2,2-bis(bromomethyl)-1,3-propanediol to cardanol in (1) is 1:1.2-1.

6.

4. The rust-proof black coating for tire screw nuts according to claim 2, characterized in that: The mass ratio of dihydroxycardanol to 2-hydroxy-5-chloropyrazine in (2) is 0.8-1.1:

1.

5. The rust-proof black coating for tire screw nuts according to claim 2, characterized in that: The mass ratio of aminopropyl-terminated polydimethylsiloxane, isophorone diisocyanate and cardanol chain extender in (3) is 1:0.9-1.3:0.01-0.

03.

6. The rust-proof black coating for tire screw nuts according to claim 1, characterized in that: The preparation method of the silicon-modified pyrazine is: S1. Add 16-18 parts by weight of cardanol chain extender and 20-26 parts by weight of acrylic acid to N,N-dimethylformamide solvent, stir to dissolve, then continue to add p-toluenesulfonic acid catalyst, react at 90-110 ° C for 10-12h, and then rotary distill, wash with acetone, and dry to obtain olefinated pyrazine; S2. Add 10-14 parts by weight of alkenyl pyrazine and 12-16 parts by weight of hexamethyldisilazane to acetonitrile solvent, stir and disperse, continue to add chloroplatinic acid catalyst, react at 55-80 ° C for 4-6h, and then distill under reduced pressure, wash and dry to obtain tertiary amino pyrazine; S3. Add 7-10 parts by weight of tertiary amino pyrazine and 8-15 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, raise the temperature to 70-85°C for reaction, the reaction time is 4-7h, and then concentrate under reduced pressure and wash with deionized water to obtain silicon-modified pyrazine.

7. A method for preparing the rust-proof black coating for tire screw nuts according to any one of claims 1 to 6, characterized in that: The method for preparing the anti-rust black coating for tire screw nuts is as follows: polyphosphoric acid, cardanol-modified polyurethane, ferrocene-modified pyrazine, black pigment, and talcum powder are added into a stirrer, and stirred for 8-14 minutes, and then the anti-rust black coating for tire screw nuts is obtained.

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