CN118813130A - A coating containing worm-like nano-silicon dioxide particles and its preparation process - Google Patents

Abstract

The invention relates to the technical field of paint, and discloses a paint containing worm-shaped nano silicon dioxide particles and a preparation process thereof, the invention adds worm-shaped nano silicon dioxide particles, fluorine-containing modified polyurethane, epoxy group perfluoro octanamide modified silane, talcum powder, BYK-071 defoamer, BYK-345 leveling agent and BYK-220S wetting dispersant into a stirrer, and stirs at room temperature to obtain the paint containing worm-shaped nano silicon dioxide particles. The sulfur element and the silicon element contained in the fluorine-containing modified polyurethane and the epoxy perfluoro-octanamide modified silane have good flame retardant effect; the quaternary ammonium salt group contained in the paint has a good antibacterial effect, and a large number of fluorine atoms contained in the paint has a good self-cleaning function; in the stirring process, the hydroxyl-terminated groups in the fluorine-containing modified polyurethane and the epoxy groups in the epoxy perfluoro-octanoyl amide modified silane are subjected to ring-opening addition, so that a tight crosslinked network is formed between the hydroxyl-terminated groups and the epoxy groups, the connection is tighter, the water absorption is lower, and a good water-resistant effect is achieved.

Description

A coating containing worm-like nano-silicon dioxide particles and its preparation process

Technical Field

The invention relates to the technical field of coatings, in particular to a coating containing worm-like nano silicon dioxide particles and a preparation process thereof.

Background Art

Fire is one of the hidden dangers of life safety. At present, people use a lot of furniture, which leads to the generation of a large amount of toxic gas in the event of a fire, affecting people's health. In addition, if it is exposed to the air for a long time, bacteria will corrode it, which will affect the quality of the furniture for a long time. The air contains a large amount of water vapor, which will be adsorbed on the surface of the furniture and sucked into the furniture, affecting its normal use. Therefore, how to avoid these phenomena is the key to solving the problem. For example, the Chinese invention patent application number 201210500460.1 discloses a method for preparing a flame retardant coating. The preparation method is simple and easy to operate. The obtained coating is composed of flame retardant, inorganic pigment, dispersant, film-forming agent, additive, pure acrylic emulsion and water. The coating has the characteristics of environmental protection, good flame retardant effect and easy availability of raw materials, but the antibacterial and water resistance properties are not improved.

Summary of the invention

1. Technical issues to be resolved

In view of the shortcomings of the prior art, the present invention provides a coating containing worm-like nano-silicon dioxide particles and a preparation process thereof, which has good flame retardant and antibacterial effects, as well as good water resistance and self-cleaning properties.

(II) Technical solution

To achieve the above object, the present invention provides the following technical solution: a coating containing worm-like nano-silica particles, comprising the following components by weight: 5-8 parts by weight of worm-like nano-silica particles, 6-10 parts by weight of fluorine-modified polyurethane, 3-6 parts by weight of epoxy perfluorooctylamide modified silane, 3-5 parts by weight of talc, 0.7-1 parts by weight of BYK-071 defoamer, 0.4-0.8 parts by weight of BYK-345 leveling agent, and 0.6-0.8 parts by weight of BYK-220S wetting and dispersing agent.

Preferably, the preparation method of the fluorine-modified polyurethane is:

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, adding pyridine catalyst, reacting at 65-80° C. for 8-14 hours, and distilling under reduced pressure after the reaction, filtering and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctylamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to dimethyl sulfoxide solvent, stirring and mixing, introducing nitrogen protection, heating to 65-80° C., applying mechanical stirring at 110-120 rpm, 300-310 W/m ² ultraviolet irradiation, stirring and reacting for 2-4 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctylamide modified silane;

(3) adding 6-10 parts by weight of perfluorooctylamide modified silane and 12-16 parts by weight of 2-bromoethanol to isopropanol solvent, and performing reflux reaction at 75-90° C., and after the reaction, performing rotary evaporation to remove the solvent, and performing recrystallization with ethanol to obtain a fluorine-containing chain extender;

(4) Mix the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introduce nitrogen, add a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 75-90° C., react for 30-45 minutes, and after the reaction is completed, cool naturally and discharge the material to obtain a fluorine-containing modified polyurethane.

Preferably, the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine and pyridine catalyst in (1) is 1:1.1-1.3:0.001-0.03.

Preferably, the mass ratio of perfluorooctanamide mercaptan, bis(dimethylamino)methylvinylsilane and dimethylphenylphosphine in (2) is 0.8-1.1:1:0.02-0.03.

Preferably, the reaction time in (3) is 8-24 hours.

Preferably, the mass ratio of the polyester polyol, hexamethylene diisocyanate, fluorine-containing chain extender and dibutyltin dilaurate catalyst in (4) is 1:1.4-1.8:1.2-1.5:0.02-0.04.

Preferably, the preparation method of the epoxy perfluorooctylamide modified silane is: add 5-8 parts by weight of perfluorooctylamide modified silane and 7-12 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stir to dissolve, react at 50-70°C for 1-3h, and then perform reduced pressure distillation, filter and dry to obtain epoxy perfluorooctylamide modified silane.

Preferably, the preparation method of the worm-like nano-silica particle coating is: add worm-like nano-silica particles, fluorine-modified polyurethane, epoxy perfluorooctylamide modified silane, talcum powder, BYK-071 defoamer, BYK-345 leveling agent, BYK-220S wetting dispersant into a stirrer, stir at room temperature for 15-20 minutes, and obtain the worm-like nano-silica particle coating.

(III) Beneficial technical effects

The invention prepares a coating containing worm-like nano silicon dioxide particles by adding worm-like nano silicon dioxide particles, fluorine-modified polyurethane, epoxy perfluorooctylamide modified silane, talcum powder, BYK-071 defoamer, BYK-345 leveling agent and BYK-220S wetting dispersant into a stirrer and stirring at room temperature.

The acyl chloride group in perfluorooctanoyl chloride reacts with the amino group in mercaptoethylamine to generate an amide group, and at the same time, a thiol group is introduced to obtain perfluorooctanoylamide thiol, which is further subjected to a click reaction with the alkenyl group in di(dimethylamino)methylvinylsilane, and at the same time, a tertiary amine group is introduced to obtain perfluorooctanoylamide modified silane. The tertiary amine group in the perfluorooctanoylamide modified silane continues to react with the bromine group in 2-bromoethanol to generate a quaternary ammonium salt group, and a large number of hydroxyl groups are introduced to obtain a fluorine-containing chain extender. Polyester polyol, hexamethylene diisocyanate and the fluorine-containing chain extender are reacted to obtain a fluorine-containing modified polyurethane. The tertiary amine group in the perfluorooctanoylamide modified silane reacts with the chlorine group in epichlorohydrin to obtain a quaternary ammonium salt group, and at the same time, an epoxy group is introduced to obtain epoxyperfluorooctanoylamide modified silane.

The sulfur element contained in the fluorine-modified polyurethane and epoxy perfluorooctylamide modified silane can release strong acid at high temperature to promote the dehydration of the substrate into carbon, isolate external oxygen and heat sources, and thus achieve a flame retardant effect. The silicon element contained therein has a large silicon-oxygen bond energy, which can not only absorb more heat, but also absorb heat to produce a glass-like substance covering the surface of the material, isolating material transportation and energy transfer, thereby achieving a flame retardant effect; the quaternary ammonium salt groups contained therein have a good antibacterial effect, and the large number of fluorine atoms contained therein have a good self-cleaning function for the coating; during the stirring process, the terminal hydroxyl groups in the fluorine-modified polyurethane will undergo ring-opening addition with the epoxy groups in the epoxy perfluorooctylamide modified silane, forming a tight cross-linking network between each other, making them more tightly connected, with lower water absorption, and having a better water-resistant effect. The worm-shaped nano-silica particles themselves also have good flame retardant and water-resistant properties.

DETAILED DESCRIPTION

Example 1

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, and continuously adding pyridine catalyst, wherein the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine, and pyridine catalyst is 1:1.1:0.01, reacting at 65° C. for 8 h, and performing reduced pressure distillation after the reaction, filtering, and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to a dimethyl sulfoxide solvent, wherein the mass ratio of perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine is 0.8:1:0.02, stirring and mixing, introducing nitrogen protection, heating to 65° C., applying mechanical stirring at 110 rpm, 300 W/m ² ultraviolet irradiation, stirring and reacting for 2 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctanamide modified silane;

(3) adding 6 parts by weight of perfluorooctylamide modified silane and 12 parts by weight of 2-bromoethanol to isopropanol solvent, and refluxing at 75° C. for 8 h. After the reaction, the solvent is removed by rotary evaporation, and recrystallized from ethanol to obtain a fluorinated chain extender;

(4) Mixing the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introducing nitrogen, adding a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 75° C., wherein the mass ratio of the polyester polyol, hexamethylene diisocyanate, the fluorine-containing chain extender, and the dibutyltin dilaurate catalyst is 1:1.4:1.2:0.002, reacting for 30 minutes, and after the reaction is completed, naturally cooling and discharging to obtain a fluorine-modified polyurethane;

(5) adding 5 parts by weight of perfluorooctylamide-modified silane and 7 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 50° C. for 1 hour, and then distilling under reduced pressure, filtering and drying to obtain epoxy perfluorooctylamide-modified silane;

(6) 5 parts by weight of worm-like nano-silica particles, 6 parts by weight of fluorine-modified polyurethane, 3 parts by weight of epoxy perfluorooctylamide modified silane, 3 parts by weight of talc, 0.7 parts by weight of BYK-071 defoamer, 0.4 parts by weight of BYK-345 leveling agent, and 0.6 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 15 minutes to obtain a coating containing worm-like nano-silica particles.

Example 2

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, and continuously adding pyridine catalyst, wherein the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine, and pyridine catalyst is 1:1.3:0.03, reacting at 80° C. for 14 h, and performing reduced pressure distillation after the reaction, filtering, and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to a dimethyl sulfoxide solvent, wherein the mass ratio of perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine is 1.1:1:0.03, stirring and mixing, introducing nitrogen protection, heating to 80° C., applying mechanical stirring at 120 rpm, 310 W/m ² ultraviolet irradiation, stirring and reacting for 4 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctanamide modified silane;

(3) adding 10 parts by weight of perfluorooctylamide modified silane and 16 parts by weight of 2-bromoethanol to isopropanol solvent, and refluxing at 90° C. for 50 h. After the reaction, the solvent is removed by rotary evaporation, and recrystallized from ethanol to obtain a fluorinated chain extender;

(4) Mixing the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introducing nitrogen, adding a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 90° C., wherein the mass ratio of the polyester polyol, hexamethylene diisocyanate, the fluorine-containing chain extender, and the dibutyltin dilaurate catalyst is 1:1.8:1.5:0.04, reacting for 45 minutes, and after the reaction is completed, naturally cooling and discharging to obtain a fluorine-modified polyurethane;

(5) adding 8 parts by weight of perfluorooctylamide-modified silane and 12 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 70° C. for 3 h, and then distilling under reduced pressure, filtering and drying to obtain epoxy perfluorooctylamide-modified silane;

(6) 8 parts by weight of worm-like nano-silica particles, 10 parts by weight of fluorine-modified polyurethane, 6 parts by weight of epoxy perfluorooctylamide modified silane, 5 parts by weight of talc, 1 part by weight of BYK-071 defoamer, 0.8 parts by weight of BYK-345 leveling agent, and 0.8 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 20 minutes to obtain a coating containing worm-like nano-silica particles.

Example 3

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, and continuously adding pyridine catalyst, wherein the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine, and pyridine catalyst is 1:1.2:0.02, reacting at 72.5° C. for 11 hours, and distilling under reduced pressure after the reaction, filtering, and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to a dimethyl sulfoxide solvent, wherein the mass ratio of perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine is 0.95:1:0.025, stirring and mixing, introducing nitrogen protection, heating to 72.5° C., applying mechanical stirring at 115 rpm, 305 W/m ² ultraviolet irradiation, stirring and reacting for 3 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctanamide modified silane;

(3) adding 8 parts by weight of perfluorooctylamide modified silane and 14 parts by weight of 2-bromoethanol to isopropanol solvent, and refluxing at 82.5° C. for 16 hours. After the reaction, the solvent is removed by rotary evaporation, and recrystallized from ethanol to obtain a fluorinated chain extender;

(4) Mixing the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introducing nitrogen, adding a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 82.5° C., wherein the mass ratio of the polyester polyol, hexamethylene diisocyanate, the fluorine-containing chain extender, and the dibutyltin dilaurate catalyst is 1:1.6:1.35:0.03, reacting for 37.5 minutes, and after the reaction is completed, naturally cooling and discharging to obtain a fluorine-modified polyurethane;

(5) adding 6.5 parts by weight of perfluorooctylamide-modified silane and 9.5 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 60° C. for 2 h, and then distilling under reduced pressure, filtering and drying to obtain epoxy perfluorooctylamide-modified silane;

(6) 6.5 parts by weight of worm-like nano-silica particles, 8 parts by weight of fluorine-modified polyurethane, 4.5 parts by weight of epoxy perfluorooctylamide modified silane, 4 parts by weight of talc, 0.85 parts by weight of BYK-071 defoamer, 0.6 parts by weight of BYK-345 leveling agent, and 0.7 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 17.5 minutes to obtain a coating containing worm-like nano-silica particles.

Example 4

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, and continuously adding pyridine catalyst, wherein the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine, and pyridine catalyst is 1:1.1:0.01, reacting at 65° C. for 8 h, and performing reduced pressure distillation after the reaction, filtering, and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to a dimethyl sulfoxide solvent, wherein the mass ratio of perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine is 0.8:1:0.02, stirring and mixing, introducing nitrogen protection, heating to 65° C., applying mechanical stirring at 110 rpm, 300 W/m ² ultraviolet irradiation, stirring and reacting for 2 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctanamide modified silane;

(3) adding 10 parts by weight of perfluorooctylamide modified silane and 16 parts by weight of 2-bromoethanol to isopropanol solvent, and refluxing at 90° C. for 24 hours. After the reaction, the solvent is removed by rotary evaporation, and recrystallized from ethanol to obtain a fluorinated chain extender;

(4) Mixing the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introducing nitrogen, adding a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 90° C., wherein the mass ratio of the polyester polyol, hexamethylene diisocyanate, the fluorine-containing chain extender, and the dibutyltin dilaurate catalyst is 1:1.8:1.5:0.04, reacting for 45 minutes, and after the reaction is completed, naturally cooling and discharging to obtain a fluorine-modified polyurethane;

(5) adding 6.5 parts by weight of perfluorooctylamide-modified silane and 9.5 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 60° C. for 2 h, and then distilling under reduced pressure, filtering and drying to obtain epoxy perfluorooctylamide-modified silane;

(6) 6.5 parts by weight of worm-like nano-silica particles, 8 parts by weight of fluorine-modified polyurethane, 4.5 parts by weight of epoxy perfluorooctylamide modified silane, 4 parts by weight of talc, 0.85 parts by weight of BYK-071 defoamer, 0.6 parts by weight of BYK-345 leveling agent, and 0.7 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 17.5 minutes to obtain a coating containing worm-like nano-silica particles.

Comparative Example 1

(1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, and continuously adding pyridine catalyst, wherein the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine, and pyridine catalyst is 1:1.1:0.01, reacting at 65° C. for 8 h, and performing reduced pressure distillation after the reaction, filtering, and drying to obtain perfluorooctanoyl amide mercaptan;

(2) adding perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to a dimethyl sulfoxide solvent, wherein the mass ratio of perfluorooctanamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine is 0.8:1:0.02, stirring and mixing, introducing nitrogen protection, heating to 65° C., applying mechanical stirring at 110 rpm, 300 W/m ² ultraviolet irradiation, stirring and reacting for 2 hours, and after completion, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctanamide modified silane;

(3) adding 10 parts by weight of perfluorooctylamide modified silane and 16 parts by weight of 2-bromoethanol to isopropanol solvent, and refluxing at 90° C. for 24 hours. After the reaction, the solvent is removed by rotary evaporation, and recrystallized from ethanol to obtain a fluorinated chain extender;

(4) Mixing the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introducing nitrogen, adding a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 90° C., wherein the mass ratio of the polyester polyol, hexamethylene diisocyanate, the fluorine-containing chain extender, and the dibutyltin dilaurate catalyst is 1:1.8:1.5:0.04, reacting for 45 minutes, and after the reaction is completed, naturally cooling and discharging to obtain a fluorine-modified polyurethane;

(6) 6.5 parts by weight of worm-like nano-silica particles, 8 parts by weight of fluorine-modified polyurethane, 4 parts by weight of talc, 0.85 parts by weight of BYK-071 defoamer, 0.6 parts by weight of BYK-345 leveling agent, and 0.7 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 17.5 minutes to obtain a coating containing worm-like nano-silica particles.

Comparative Example 2

(1) adding 6.5 parts by weight of perfluorooctylamide-modified silane and 9.5 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stirring to dissolve, reacting at 60° C. for 2 h, and then distilling under reduced pressure, filtering and drying to obtain epoxy perfluorooctylamide-modified silane;

(2) 6.5 parts by weight of worm-like nano-silica particles, 4.5 parts by weight of epoxy perfluorooctylamide modified silane, 4 parts by weight of talc, 0.85 parts by weight of BYK-071 defoamer, 0.6 parts by weight of BYK-345 leveling agent, and 0.7 parts by weight of BYK-220S wetting and dispersing agent were added into a stirrer and stirred at room temperature for 17.5 minutes to obtain a coating containing worm-like nano-silica particles.

Performance Testing

The limiting oxygen index of the material was tested using an oxygen index meter, and the combustion grade of the material was tested using a horizontal and vertical combustion instrument. The test results are shown in Table 1.

Table 1: Flame retardancy tests.

project Limiting oxygen index (%) Combustion level Example 1 31 V-0 Example 2 33 V-0 Example 3 32 V-0 Example 4 31 V-0 Comparative Example 1 twenty one V-1 Comparative Example 2 twenty two V-1

It can be seen from Table 1 that Examples 1-4 of the present invention have better flame retardant effects than Comparative Examples 1-2.

Antibacterial performance: Carefully tear off the coating and cut it into a 10mm diameter disc, sterilize it with a UV lamp, add it to 10mL solid agar medium and culture it with Staphylococcus aureus (10μL, 106CFU/mL) in a 37℃ incubator for 12 hours. The experiment uses three groups of parallel controls and takes the average value. The blank control is carried out without the coating, and then the CFU count is determined. The calculation formula of the antibacterial rate is shown as follows: Antibacterial rate (%) = (1-C/N) × 100%. Among them, N is the average number of live bacteria in the blank control group after 12h, and C is the average number of live bacteria in the experimental group after 12h. The test results are shown in Table 2.

Table 2: Antibacterial rate test.

It can be seen from Table 2 that Examples 1-4 of the present invention have better antibacterial properties than Comparative Examples 1-2.

The water resistance of waterproof coatings was tested according to the method in GB/T16777-2008 "Test methods for building waterproof coatings". The prepared coating containing worm-like nano-silica particles was weighed, immersed in 20±2℃ water for 24h, taken out and quickly wiped off the free moisture on the surface of the specimen, and weighed again to calculate the water absorption rate. The test results are shown in Table 3.

Table 3: Coating waterproof test.

project Water absorption (%) Example 1 6.2 Example 2 6.0 Example 3 6.1 Example 4 6.1 Comparative Example 1 11.3 Comparative Example 2 10.2

It can be seen from Table 3 that Examples 1-4 of the present invention have lower water absorption rates than Comparative Examples 1-2, indicating better waterproofing effects.

The coatings of Examples 1-4 and Comparative Examples 1-2 were sprayed into coatings, and the surface wettability was characterized according to JC2000D, and the contact angle test was performed.

Table 4: Contact angle test.

project Contact Angle Example 1 126.7° Example 2 128.6° Example 3 127.1° Example 4 128.3° Comparative Example 1 104.6° Comparative Example 2 103.5°

As can be seen from Table 4, compared with Comparative Example 1-2, the contact angle of Example 1-4 is larger, resulting in that the water droplets cannot spread and are very easy to slide, indicating that the coating prepared by the present invention has a good self-cleaning function.

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 (7)

1. A coating containing worm-like nano-silica particles, characterized in that it comprises the following components by weight: 5-8 parts by weight of worm-like nano-silica particles, 6-10 parts by weight of fluorine-modified polyurethane, 3-6 parts by weight of epoxy perfluorooctylamide modified silane, 3-5 parts by weight of talc, 0.7-1 parts by weight of BYK-071 defoamer, 0.4-0.8 parts by weight of BYK-345 leveling agent, and 0.6-0.8 parts by weight of BYK-220S wetting and dispersing agent; The preparation method of the fluorine-modified polyurethane is as follows: (1) adding perfluorooctanoyl chloride and mercaptoethylamine to N,N-dimethylformamide solvent, stirring to dissolve, adding pyridine catalyst, reacting at 65-80° C. for 8-14 hours, and distilling under reduced pressure after the reaction, filtering and drying to obtain perfluorooctanoyl amide mercaptan; (2) adding perfluorooctylamide mercaptan, di(dimethylamino)methylvinylsilane and dimethylphenylphosphine to dimethyl sulfoxide solvent, stirring and mixing, introducing nitrogen protection, heating to 65-80° C., applying mechanical stirring at 110-120 rpm, 300-310 W/m ² ultraviolet irradiation, stirring and reacting for 2-4 hours, and after the reaction, removing the solvent by vacuum rotary evaporation, washing, and drying to obtain perfluorooctylamide modified silane; (3) adding 6-10 parts by weight of perfluorooctylamide modified silane and 12-16 parts by weight of 2-bromoethanol to isopropanol solvent, and performing reflux reaction at 75-90° C., and after the reaction, performing rotary evaporation to remove the solvent, and performing recrystallization with ethanol to obtain a fluorine-containing chain extender; (4) Mix the vacuum dried and dehydrated polyester polyol and hexamethylene diisocyanate, introduce nitrogen, add a fluorine-containing chain extender and a dibutyltin dilaurate catalyst at 75-90° C., react for 30-45 minutes, and after the reaction is completed, cool naturally and discharge the material to obtain a fluorine-containing modified polyurethane. 2. The worm-like nano-silica particle coating according to claim 1, characterized in that the mass ratio of perfluorooctanoyl chloride, mercaptoethylamine and pyridine catalyst in (1) is 1:1.1-1.3:0.001-0.03. 3. The worm-like nano-silica particle coating according to claim 1, characterized in that the mass ratio of perfluorooctanamide mercaptan, bis(dimethylamino)methylvinylsilane and dimethylphenylphosphine in (2) is 0.8-1.1:1:0.02-0.03. 4. The coating containing worm-like nano-silicon dioxide particles according to claim 1, characterized in that the reaction time in (3) is 8-24 hours. 5. The worm-like nano-silica particle coating according to claim 1, characterized in that the mass ratio of polyester polyol, hexamethylene diisocyanate, fluorine-containing chain extender and dibutyltin dilaurate catalyst in (4) is 1:1.4-1.8:1.2-1.5:0.02-0.04. 6. The worm-like nano-silica particle coating according to claim 1 is characterized in that the preparation method of the epoxy perfluorooctylamide modified silane is: add 5-8 parts by weight of perfluorooctylamide modified silane and 7-12 parts by weight of epichlorohydrin to N,N-dimethylformamide solvent, stir to dissolve, react at 50-70°C for 1-3h, and then distill under reduced pressure, filter and dry to obtain epoxy perfluorooctylamide modified silane. 7. A method for preparing a coating containing worm-like nano-silica particles as described in any one of claims 1 to 6, characterized in that the method for preparing the coating containing worm-like nano-silica particles is: adding worm-like nano-silica particles, fluorine-modified polyurethane, epoxy perfluorooctylamide modified silane, talcum powder, BYK-071 defoamer, BYK-345 leveling agent, and BYK-220S wetting and dispersing agent into a stirrer, stirring at room temperature for 15-20 minutes to obtain a coating containing worm-like nano-silica particles.