Infrared shielding coating and preparation method thereof

Abstract

The invention discloses an infrared shielding coating and a preparation method thereof, and relates to the technical field of coatings. The infrared shielding coating prepared by the present invention comprises modified polyvinyl chloride, silicon crown ether, modified cobalt blue, and chloroplatinic acid; the modified polyvinyl chloride is polyvinyl chloride after 4-amino-2,2,6,6-tetramethylpiperidine-1-oxygen free radical pretreatment, and 4,4'-diaminobenzophenone reacts to obtain aminophenyl polyvinyl chloride, and then reacts with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, and then reacts with silver hexafluoride antimonate to obtain; the modified cobalt blue is obtained by polymerization of aniline on the surface of cobalt blue pretreated with a silane coupling agent, and then grafting 1-(chloro-methylphosphoryl)ethylene. The infrared shielding coating prepared by the present invention has excellent infrared shielding, self-repairing and flame retardant properties.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, in particular to an infrared shielding coating and a preparation method thereof. Background Art

[0002] With the continuous progress of science, reconnaissance technology has developed rapidly, and various high-end reconnaissance equipment has been put into use in large quantities. Modern detection equipment has a high utilization rate of electromagnetic waves. There are high-precision detection equipment in all bands from short-wave ultraviolet to long-wave millimeter waves and radar waves above millimeters. Stealth technology is to counter detection technology, which can be mainly summarized as visible light stealth, infrared stealth, laser stealth, radar stealth, and acoustic stealth.

[0003] Infrared stealth technology is to reduce and change the intensity and characteristics of infrared radiation by shielding, coating with low emissivity coating, heat suppression and other measures, so that detection equipment cannot detect it and achieve stealth effect. As a kind of stealth material technology, infrared stealth coating has the characteristics of simple construction, low cost, strong adaptability and flexibility. However, a single infrared stealth coating can no longer meet the use requirements in different environments. For example, equipment coated with coating may face various fire sources and high temperature environments. Coatings with flame retardant function can prevent the spread of fire to a certain extent, reduce the risk of equipment damage due to fire, and improve the safety of equipment. Coatings with self-repairing function can automatically repair or reduce the degree of damage after the coating is damaged, thereby extending the service life of the coating and reducing maintenance costs. Summary of the invention

[0004] The purpose of the present invention is to provide an infrared shielding coating and a preparation method thereof to solve the problems existing in the prior art.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] An infrared shielding paint comprises the following raw materials in parts by mass: 100 parts of modified polyvinyl chloride, 10-15 parts of silicon crown ether, 10-12 parts of modified cobalt blue, and 3-5 parts of chloroplatinic acid.

[0007] As an optimization, the modified polyvinyl chloride is obtained by pre-treating polyvinyl chloride with 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, reacting it with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, reacting it with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, and then reacting it with silver hexafluoride antimonate.

[0008] As an optimization, the modified cobalt blue is obtained by polymerizing aniline on the surface of cobalt blue pretreated with a silane coupling agent and then grafting 1-(chloro-methylphosphinoyl)ethylene.

[0009] A method for preparing an infrared shielding coating, the method comprising the following steps:

[0010] (1) Polyvinyl chloride, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and N,N-dimethylformamide are uniformly mixed in a mass ratio of 1:(0.3-0.5):(50-60), heated to 50-60°C and stirred for 2 hours, then cooled to room temperature and stirred for 3-4 hours, and vacuum rotary evaporation is performed to remove N,N-dimethylformamide to obtain pretreated polyvinyl chloride;

[0011] (2) Pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran are mixed in a mass ratio of 1:(2-3):(50-60), and a 30wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran is added dropwise at 5-10°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride is added, and the temperature is raised to 20-30°C. After reacting for 24 hours, tetrahydrofuran is removed by vacuum rotary evaporation to obtain aminophenyl polyvinyl chloride; aminophenyl polyvinyl chloride, 4-iodostyrene, potassium carbonate and tetrahydrofuran are mixed in a mass ratio of 1:(5-6):(1-2):(20-30), and the reaction is performed for 5-6 hours. After the reaction is completed, the mixture is cooled to room temperature, and tetrahydrofuran is removed by vacuum rotary evaporation to obtain triphenylamine polyvinyl chloride;

[0012] (3) Mix triphenylamine polyvinyl chloride, silver hexafluoride antimonate, and tetrahydrofuran in a mass ratio of 1:(2-3):(20-30), stir for 2-3 hours in a dark environment, filter and retain the filtrate, and remove tetrahydrofuran by vacuum rotary evaporation to obtain modified polyvinyl chloride;

[0013] (4) Weigh pretreated cobalt blue, aniline, 2 wt% polyvinyl pyrrolidone aqueous solution, 0.6 mol / L hydrochloric acid aqueous solution, and ammonium persulfate in a mass ratio of 1:1:(50-60):(25-30):(0.3-0.5), ultrasonically mix the pretreated cobalt blue and 2 wt% polyvinyl pyrrolidone aqueous solution at 0-2°C for 30 min, add hydrochloric acid aqueous solution and aniline, stir for 3-4 h at a stirring speed of 500 r / min, add ammonium persulfate and continue stirring for 3-4 h, filter and wash with anhydrous ethanol 3-4 times, and dry at 60°C for 6-8 h to obtain pre-modified cobalt blue;

[0014] (5) Pre-modified cobalt blue, 1-(chloro-methylphosphinoyl)ethylene and 1,2-dichloroethane were mixed in a mass ratio of 1:(0.5-0.7):(50-60), heated to 87-92°C and refluxed for 10-12 hours, pure water equal in volume to 1,2-dichloroethane was added and stirred for 3 minutes, filtered and washed with pure water for 3-4 times, and dried at 60°C for 6-8 hours to obtain modified cobalt blue;

[0015] (6) Weigh the following raw materials: modified polyvinyl chloride, modified cobalt blue, silicon crown ether, and chloroplatinic acid, put the above raw materials into a high-speed mixer and mix them for 5 minutes, then put them into a twin-screw extruder for melt extrusion, use a pelletizer to pelletize after extrusion, grind them with a grinder, and pass them through a 180-mesh sieve to obtain an infrared shielding coating.

[0016] As an optimization, the preparation method of the pretreated cobalt blue in step (4) is: cobalt blue, silane coupling agent, and anhydrous ethanol are mixed in a mass ratio of 1: (5-6): (100-120), ultrasonically shaken for 20-30 minutes, heated to 40°C, stirred and mixed for 1-2 hours, filtered and washed with anhydrous ethanol for 3-4 times, and dried at 60°C for 6-8 hours to obtain pretreated cobalt blue.

[0017] As an optimization, the silane coupling agent is (3-trimethoxysilylpropoxy)aniline; the cobalt blue model is B2805.

[0018] As an optimization, the preparation method of the silicon crown ether in step (6) is as follows: weigh tri(4-methoxyphenyl)silane and boron tribromide in a molar ratio of 1:5; mix tri(4-methoxyphenyl)silane and dichloromethane in a mass ratio of 1:20 to obtain a silane solution; mix boron tribromide and dichloromethane in a mass ratio of 1:20 to obtain a boron tribromide solution; under nitrogen protection, at -52°C, drop the boron tribromide solution into the silane solution and start stirring, the dropping speed is 0.5 mL / min, the stirring speed is 150 r / min, 10 wt% dilute sulfuric acid (3 times the mass of boron tribromide) is added and stirred for 3 min, filtered and vacuum dried for 12 h to obtain tri(4-phenolic hydroxyphenyl)silane; weigh tri(4-phenolic hydroxyphenyl)silane and diethylene glycol di-p-toluenesulfonate in a molar ratio of 1:1.4; under nitrogen protection, add tri(4-phenolic hydroxyphenyl)silane and diethylene glycol di-p-toluenesulfonate; The mixture was stirred for 30 min at a mass ratio of 1:0.3:35, with a rotation speed of 150 r / min, and potassium hydroxide with a mass ratio of 0.3 times that of tri(4-phenolhydroxyphenyl)silane was added again, and the stirring was continued for 30 min to obtain a phenolhydroxysilane solution. Diethylene glycol di-p-toluenesulfonate and tetrahydrofuran were mixed at a mass ratio of 1:35 to obtain a sulfonate solution, and the sulfonate solution was added dropwise to the phenolhydroxysilane solution at a dropping speed of 0.5 mL / min. After the addition was completed, the temperature was raised to 72°C for reflux reaction and stirred for 36 h at a stirring speed of 150 r / min. After the stirring was completed, the tetrahydrofuran was removed by vacuum rotary evaporation to obtain a silyl crown ether; the silyl crown ether, manganese nitrate, and methanol were mixed at a mass ratio of 1:0.7:10, stirred at 50°C for 2 h, and the methanol was removed by vacuum rotary evaporation to obtain a silicon crown ether.

[0019] As an optimization, the weighed amounts of the raw materials in step (6) are: by mass, 100 parts of modified polyvinyl chloride, 10-15 parts of silicon crown ether, 10-12 parts of modified cobalt blue, and 3-5 parts of chloroplatinic acid; the temperature of the twin-screw extruder is 120°C.

[0020] As an optimization, the polyvinyl chloride model in step (1) is SG-8.

[0021] As an optimization, the preparation process of modified polyvinyl chloride is as follows:

[0022] ;

[0023] As an optimization, the schematic diagram of aniline polymerization and grafting 1-(chloro-methylphosphinoyl)ethylene on the surface of modified cobalt blue is shown below:

[0024] ;

[0025] Compared with the prior art, the beneficial effects achieved by the present invention are:

[0026] The infrared shielding coating prepared by the invention comprises modified polyvinyl chloride, silicon crown ether, modified cobalt blue and chloroplatinic acid; wherein the modified polyvinyl chloride is prepared by pre-treating polyvinyl chloride with 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, reacting with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, reacting with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, and reacting with silver hexafluoride antimonate to obtain the obtained product; the modified cobalt blue is prepared by polymerizing aniline on the surface of cobalt blue pre-treated with a silane coupling agent, and then grafting 1-(chloro-methylphosphinoyl)ethylene.

[0027] First, polyvinyl chloride is pretreated with 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, and then reacted with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, which is then reacted with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, which is then reacted with silver hexafluoride antimonate to obtain modified polyvinyl chloride; the polyvinyl chloride molecule contains a strongly polar C-Cl bond, which can undergo nucleophilic substitution with the amino group on the 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, so that the polyvinyl chloride is grafted with a nitroxide free radical, and the nitroxide free radical reacts with the symmetrical ketone 4,4'-diaminobenzophenone to form an alkoxyamine bond. , and aminophenyl is grafted onto the side chain of polyvinyl chloride. The alkoxyamine bond can break and recombine under certain conditions, and the free radicals generated by the break can undergo exchange reactions. This dynamic exchange property can give the coating formed by the paint the ability to self-repair. Aminophenyl reacts with 4-iodostyrene to form a triphenylamine structure containing a vinyl group, which then reacts with silver hexafluoride antimonate to transform the triphenylamine structure into a triphenylamine organic salt. Triphenylamine is a three-dimensional propeller-shaped large conjugated aromatic amine system with excellent photochemical properties. Aromatic amine organic salts are a type of good infrared absorbing organic matter, which can give the coating good infrared absorption properties.

[0028] Secondly, aniline is polymerized on the surface of cobalt blue pretreated with a silane coupling agent, and then 1-(chloro-methylphosphoryl)ethylene is grafted to obtain modified cobalt blue. Cobalt blue is a common infrared reflective inorganic pigment, and its reflective property is caused by irregular protrusions in its powder structure. The surface of cobalt blue treated with a silane coupling agent has aniline functional groups, which can participate in the polymerization of aniline to form polyaniline. Polyaniline, as an important conductive polymer, has a high infrared reflectivity and can improve the infrared shielding performance of the coating. 1-(chloro-methylphosphoryl)ethylene can graft phosphorus elements and vinyl groups with flame-retardant structures on the surface of cobalt blue through the reaction with polyaniline, thereby further improving the flame retardant properties of the coating.

[0029] Finally, the modified polyvinyl chloride, silicon crown ether, modified cobalt blue and chloroplatinic acid are mixed and granulated to obtain an infrared shielding coating. The silicon crown ether is obtained by complexing metal manganese with silicon hydrogen crown ether, has certain magnetism, can absorb and dissipate infrared rays, and also has certain wave absorbing properties. The modified polyvinyl chloride side chain has double bonds, and the surface of the modified cobalt blue also has double bonds. The silicon crown ether containing silicon hydrogen bonds can be used as a cross-linking agent to cause cross-linking during the mixing process, and the formed cross-linked structure can increase the mechanical properties of the coating. DETAILED DESCRIPTION

[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0031] The polyvinyl chloride model used in the following examples and comparative examples is SG-8; the cobalt blue model used is B2805; and the silane coupling agent used is (3-trimethoxysilylpropoxy)aniline.

[0032] The preparation method of the silicon crown ether used in the following examples and comparative examples is as follows: weigh tri(4-methoxyphenyl)silane and boron tribromide in a molar ratio of 1:5; mix tri(4-methoxyphenyl)silane and dichloromethane in a mass ratio of 1:20 to obtain a silane solution, mix boron tribromide and dichloromethane in a mass ratio of 1:20 to obtain a boron tribromide solution, under nitrogen protection, at -52°C, dropwise add the boron tribromide solution to the silane solution and start stirring, the dropping speed is 0.5mL / min, the stirring speed is 150r / min, add 10wt% dilute sulfuric acid 3 times the mass of boron tribromide and stir for 3min, filter and vacuum dry for 12h to obtain tri(4-phenolic hydroxyphenyl)silane; weigh tri(4-phenolic hydroxyphenyl)silane and diethylene glycol bis-p-toluenesulfonate in a molar ratio of 1:1.4, under nitrogen protection, add tri(4-phenolic hydroxyphenyl)silane and diethylene glycol bis-p-toluenesulfonate. The mixture was stirred for 30 min at a mass ratio of 1:0.3:35, with a rotation speed of 150 r / min, and potassium hydroxide with a mass ratio of 0.3 times that of tri(4-phenolhydroxyphenyl)silane was added again, and the stirring was continued for 30 min to obtain a phenolhydroxysilane solution. Diethylene glycol di-p-toluenesulfonate and tetrahydrofuran were mixed at a mass ratio of 1:35 to obtain a sulfonate solution, and the sulfonate solution was added dropwise to the phenolhydroxysilane solution at a dropping speed of 0.5 mL / min. After the addition was completed, the temperature was raised to 72°C for reflux reaction and stirred for 36 h at a stirring speed of 150 r / min. After the stirring was completed, the tetrahydrofuran was removed by vacuum rotary evaporation to obtain a silyl crown ether; the silyl crown ether, manganese nitrate, and methanol were mixed at a mass ratio of 1:0.7:10, stirred at 50°C for 2 h, and the methanol was removed by vacuum rotary evaporation to obtain a silicon crown ether.

[0033] Embodiment 1:

[0034] (1) Polyvinyl chloride, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and N,N-dimethylformamide were uniformly mixed in a mass ratio of 1:0.3:50, heated to 60°C and stirred for 2 hours, then cooled to room temperature and stirred for 4 hours, and vacuum rotary evaporation was performed to remove N,N-dimethylformamide to obtain pretreated polyvinyl chloride;

[0035] (2) Pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran were mixed in a mass ratio of 1:2:50, and a 30 wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran was added dropwise at 10°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride was added, and the temperature was raised to 30°C. After reacting for 24 hours, tetrahydrofuran was removed by vacuum rotary evaporation to obtain aminophenyl polyvinyl chloride; aminophenyl polyvinyl chloride, 4-iodostyrene, potassium carbonate and tetrahydrofuran were mixed in a mass ratio of 1:5:1:20, and reacted for 6 hours. After the reaction was completed, the mixture was cooled to room temperature, and tetrahydrofuran was removed by vacuum rotary evaporation to obtain triphenylamine polyvinyl chloride;

[0036] (3) triphenylamine polyvinyl chloride, silver hexafluoride antimonate, and tetrahydrofuran are mixed in a mass ratio of 1:2:20, stirred for 3 hours in a dark environment, filtered and retained, and tetrahydrofuran is removed by vacuum rotary evaporation to obtain modified polyvinyl chloride;

[0037] (4) Cobalt blue, silane coupling agent and anhydrous ethanol were mixed in a mass ratio of 1:5:100, ultrasonically vibrated for 30 minutes, heated to 40°C, stirred and mixed for 2 hours, filtered and washed with anhydrous ethanol for 4 times, and dried at 60°C for 8 hours to obtain pretreated cobalt blue; pretreated cobalt blue, aniline, 2wt% polyvinyl pyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate were weighed in a mass ratio of 1:1:50:25:0.3, and the pretreated cobalt blue and 2wt% polyvinyl pyrrolidone aqueous solution were ultrasonically mixed for 30 minutes at 2°C, hydrochloric acid aqueous solution and aniline were added, stirred for 4 hours at a stirring speed of 500r / min, ammonium persulfate was added and stirred for 4 hours, filtered and washed with anhydrous ethanol for 4 times, and dried at 60°C for 8 hours to obtain pre-modified cobalt blue;

[0038] (5) Pre-modified cobalt blue, 1-(chloro-methylphosphinoyl)ethylene, and 1,2-dichloroethane were mixed in a mass ratio of 1:0.5:50, heated to 92°C and refluxed for 12 h, pure water equal in volume to 1,2-dichloroethane was added and stirred for 3 min, filtered and washed with pure water for 4 times, and dried at 60°C for 8 h to obtain modified cobalt blue;

[0039] (6) Weigh the following raw materials: 100 parts by mass of modified polyvinyl chloride, 10 parts by mass of silicon crown ether, 10 parts by mass of modified cobalt blue, and 3 parts by mass of chloroplatinic acid; put the above raw materials into a high-speed mixer and mix for 5 minutes, then put them into a twin-screw extruder for melt extrusion. The temperature of the twin-screw extruder is 120°C. After extrusion, use a pelletizer to cut the pellets, grind them with a grinder, and pass through a 180-mesh sieve to obtain an infrared shielding coating.

[0040] Embodiment 2:

[0041] (1) Polyvinyl chloride, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and N,N-dimethylformamide were uniformly mixed in a mass ratio of 1:0.4:55, heated to 55°C and stirred for 2 hours, then cooled to room temperature and stirred for 3.5 hours, and N,N-dimethylformamide was removed by vacuum rotary evaporation to obtain pretreated polyvinyl chloride;

[0042] (2) Pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran were mixed in a mass ratio of 1:2.5:55, and a 30 wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran was added dropwise at 7°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride was added, and the temperature was raised to 25°C. After reacting for 24 hours, tetrahydrofuran was removed by vacuum rotary evaporation to obtain aminophenyl polyvinyl chloride; aminophenyl polyvinyl chloride, 4-iodostyrene, potassium carbonate and tetrahydrofuran were mixed in a mass ratio of 1:5.5:1.5:25, and reacted for 5.5 hours. After the reaction was completed, the mixture was cooled to room temperature, and tetrahydrofuran was removed by vacuum rotary evaporation to obtain triphenylamine polyvinyl chloride;

[0043] (3) triphenylamine polyvinyl chloride, silver hexafluoride antimonate, and tetrahydrofuran are mixed in a mass ratio of 1:2.5:25, stirred for 2.5 hours in a dark environment, filtered and retained the filtrate, and tetrahydrofuran is removed by vacuum rotary evaporation to obtain modified polyvinyl chloride;

[0044] (4) Cobalt blue, silane coupling agent and anhydrous ethanol were mixed in a mass ratio of 1:5.6:110, ultrasonically vibrated for 25 minutes, heated to 40°C, stirred and mixed for 1.5 hours, filtered and washed with anhydrous ethanol for 3 times, and dried at 60°C for 6.5 hours to obtain pretreated cobalt blue; pretreated cobalt blue, aniline, 2wt% polyvinyl pyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate were weighed in a mass ratio of 1:1:55:27:0.4, and the pretreated cobalt blue and 2wt% polyvinyl pyrrolidone aqueous solution were ultrasonically mixed for 30 minutes at 1°C, hydrochloric acid aqueous solution and aniline were added, stirred for 3.5 hours at a stirring speed of 500r / min, ammonium persulfate was added and stirred for 3.5 hours, filtered and washed with anhydrous ethanol for 3 times, and dried at 60°C for 7 hours to obtain pre-modified cobalt blue;

[0045] (5) Pre-modified cobalt blue, 1-(chloro-methylphosphinoyl)ethylene, and 1,2-dichloroethane were mixed in a mass ratio of 1:0.5:55, heated to 90°C and refluxed for 11 hours, pure water equal in volume to 1,2-dichloroethane was added and stirred for 3 minutes, filtered and washed with pure water for 3 times, and dried at 60°C for 7 hours to obtain modified cobalt blue;

[0046] (6) Weigh the following raw materials: 100 parts by mass of modified polyvinyl chloride, 13 parts by mass of silicon crown ether, 11 parts by mass of modified cobalt blue, and 4 parts by mass of chloroplatinic acid; put the above raw materials into a high-speed mixer and mix for 5 minutes, then put them into a twin-screw extruder for melt extrusion at a temperature of 120°C. After extrusion, use a pelletizer to cut the pellets, grind them with a grinder, and pass them through a 180-mesh sieve to obtain an infrared shielding coating.

[0047] Embodiment 3:

[0048] (1) Polyvinyl chloride, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and N,N-dimethylformamide were uniformly mixed in a mass ratio of 1:0.5:60, heated to 50°C and stirred for 2 hours, then cooled to room temperature and stirred for 3 hours, and N,N-dimethylformamide was removed by vacuum rotary evaporation to obtain pretreated polyvinyl chloride;

[0049] (2) Pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran were mixed in a mass ratio of 1:3:60, and a 30 wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran was added dropwise at 5°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride was added, and the temperature was raised to 30°C. After reacting for 24 hours, tetrahydrofuran was removed by vacuum rotary evaporation to obtain aminophenyl polyvinyl chloride; aminophenyl polyvinyl chloride, 4-iodostyrene, potassium carbonate and tetrahydrofuran were mixed in a mass ratio of 1:6:2:30, and reacted for 5 hours. After the reaction was completed, the mixture was cooled to room temperature, and tetrahydrofuran was removed by vacuum rotary evaporation to obtain triphenylamine polyvinyl chloride;

[0050] (3) triphenylamine polyvinyl chloride, silver hexafluoride antimonate, and tetrahydrofuran are mixed in a mass ratio of 1:3:30, stirred for 2 hours in a dark environment, filtered and retained the filtrate, and tetrahydrofuran is removed by vacuum rotary evaporation to obtain modified polyvinyl chloride;

[0051] (4) Cobalt blue, silane coupling agent and anhydrous ethanol were mixed in a mass ratio of 1:6:120, ultrasonically vibrated for 20 minutes, heated to 40°C, stirred and mixed for 1 hour, filtered and washed with anhydrous ethanol for 3 times, and dried at 60°C for 6 hours to obtain pretreated cobalt blue; pretreated cobalt blue, aniline, 2wt% polyvinyl pyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution and ammonium persulfate were weighed in a mass ratio of 1:1:60:30:0.5, and the pretreated cobalt blue and 2wt% polyvinyl pyrrolidone aqueous solution were ultrasonically mixed for 30 minutes at 0°C, hydrochloric acid aqueous solution and aniline were added, stirred for 3 hours at a stirring speed of 500r / min, ammonium persulfate was added and stirred for 3 hours, filtered and washed with anhydrous ethanol for 3 times, and dried at 60°C for 6 hours to obtain pre-modified cobalt blue;

[0052] (5) Pre-modified cobalt blue, 1-(chloro-methylphosphinoyl)ethylene, and 1,2-dichloroethane were mixed in a mass ratio of 1:0.7:60, heated to 87°C and refluxed for 10 h, pure water equal in volume to 1,2-dichloroethane was added and stirred for 3 min, filtered and washed with pure water 3 times, and dried at 60°C for 6 h to obtain modified cobalt blue;

[0053] (6) Weigh the following raw materials: 100 parts by mass of modified polyvinyl chloride, 15 parts by mass of silicon crown ether, 12 parts by mass of modified cobalt blue, and 5 parts by mass of chloroplatinic acid; put the above raw materials into a high-speed mixer and mix for 5 minutes, then put them into a twin-screw extruder for melt extrusion. The temperature of the twin-screw extruder is 120°C. After extrusion, use a pelletizer to cut the pellets, grind them with a grinder, and pass them through a 180-mesh sieve to obtain an infrared shielding coating.

[0054] Comparative Example 1:

[0055] The preparation method of the infrared shielding coating of Comparative Example 1 differs from that of Example 2 in that steps (1), (2) and (3) are not included, and step (6) is modified as follows: weigh the following raw materials: 100 parts of polyvinyl chloride, 13 parts of silicon crown ether, 11 parts of modified cobalt blue, and 4 parts of chloroplatinic acid, by mass; put the above raw materials into a high-speed mixer and mix for 5 minutes, then put them into a twin-screw extruder for melt extrusion, the temperature of the twin-screw extruder is 120°C, and after extrusion, use a pelletizer to cut the pellets, grind them with a grinder, and pass through a 180-mesh sieve to obtain an infrared shielding coating.

[0056] Comparative Example 2:

[0057] The preparation method of the infrared shielding coating of Comparative Example 2 differs from that of Example 2 in that step (3) is not included, and step (2) is modified as follows: pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran are uniformly mixed in a mass ratio of 1:2.5:55, a 30 wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran is added dropwise at 7°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride is added, the temperature is raised to 25°C, and after reacting for 24 hours, the tetrahydrofuran is removed by reduced pressure rotary evaporation to obtain modified polyvinyl chloride.

[0058] Comparative Example 3:

[0059] The preparation method of the infrared shielding coating of Comparative Example 3 differs from that of Example 2 in that steps (4) and (5) are not included, and step (6) is modified as follows: weigh the following raw materials: 100 parts by mass of modified polyvinyl chloride, 13 parts by mass of silicon crown ether, 11 parts by mass of cobalt blue, and 4 parts by mass of chloroplatinic acid; put the above raw materials into a high-speed mixer and mix for 5 minutes, and then put them into a twin-screw extruder for melt extrusion. The temperature of the twin-screw extruder is 120°C. After extrusion, a pelletizer is used for pelletizing, a grinder is used for grinding, and the mixture is sieved through a 180-mesh sieve to obtain an infrared shielding coating.

[0060] Comparative Example 4:

[0061] The preparation method of the infrared shielding coating of Comparative Example 4 differs from that of Example (2) in that step (5) is not included, and step (4) is modified as follows: cobalt blue, silane coupling agent, and anhydrous ethanol are mixed in a mass ratio of 1:5.6:110, ultrasonically oscillated for 25 minutes, heated to 40°C, stirred and mixed for 1.5 hours, filtered and washed with anhydrous ethanol three times, and dried at 60°C for 6.5 hours to obtain pretreated cobalt blue; pretreated cobalt blue, aniline, 2wt% polyvinyl pyrrolidone aqueous solution, 0.6mol / L hydrochloric acid aqueous solution, and ammonium persulfate are weighed in a mass ratio of 1:1:55:27:0.4, and the pretreated cobalt blue and 2wt% polyvinyl pyrrolidone aqueous solution are ultrasonically mixed for 30 minutes at 1°C, hydrochloric acid aqueous solution and aniline are added, stirred for 3.5 hours at a stirring speed of 500r / min, ammonium persulfate is added and stirred for 3.5 hours, filtered and washed with anhydrous ethanol three times, and dried at 60°C for 7 hours to obtain modified cobalt blue.

[0062] Test Example 1:

[0063] Preparation of coating: The infrared shielding coating prepared in the embodiment and the comparative example was sprayed on the surface of a 20×50×0.28 mm tinplate sheet by an electrostatic spraying method through a 50 kV high-voltage electrostatic field at a current of 60 A and a spraying pressure of 0.4 MPa. The coating thickness was 30 μm. The tinplate sheet was placed in an oven at 180°C for curing for 10 min to obtain an infrared shielding coating.

[0064] Flame retardant performance test:

[0065] Test method: Test the limiting oxygen index of the coating according to standard GB / T 2406.2-2009. The results are shown in Table 1.

[0066] Table 1

[0067] Limiting oxygen index (%) Limiting oxygen index (%) Example 1 31.4 Comparative Example 1 22.5 Example 2 32.0 Comparative Example 2 31.2 Example 3 31.7 Comparative Example 3 31.5 Comparative Example 4 26.1

[0068] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 1, it can be found that the infrared shielding coating prepared by the present invention has good flame retardancy.

[0069] By comparison, the limiting oxygen index of Examples 1 to 3 is greater than that of Comparative Examples 1 to 4, indicating that aniline is polymerized on the surface of cobalt blue pretreated with a silane coupling agent, and then 1-(chloro-methylphosphoryl)ethylene is grafted to obtain modified cobalt blue. 1-(chloro-methylphosphoryl)ethylene can graft phosphorus elements and vinyl groups with flame-retardant structures on the surface of cobalt blue through the reaction with polyaniline, thereby further improving the flame retardant properties of the coating.

[0070] Test Example 2:

[0071] Infrared shielding performance test:

[0072] The infrared shielding coating was prepared according to the coating preparation method of Test Example 1, and the infrared transmittance was tested according to the standard GB / T36403-2018 after the coating was peeled off. The results are shown in Table 2.

[0073] Table 2

[0074] Infrared transmittance (%) Infrared transmittance (%) Example 1 14.7 Comparative Example 1 52.4 Example 2 15.6 Comparative Example 2 52.6 Example 3 15.1 Comparative Example 3 47.1 Comparative Example 4 45.4

[0075] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 2, it can be found that the infrared shielding coating prepared by the present invention has good infrared shielding performance.

[0076] By comparison, the infrared transmittance of Examples 1 to 3 is greater than that of Comparative Examples 1 to 4, indicating that, first, polyvinyl chloride is pretreated with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, and then reacted with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, which is then reacted with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, which is then reacted with silver hexafluoride antimonate to obtain modified polyvinyl chloride; aminophenyl reacts with 4-iodostyrene to form a triphenylamine structure containing a vinyl group, which is then reacted with silver hexafluoride antimonate to convert the triphenylamine structure into a triphenylamine organic salt. Triphenylamine is a three-dimensional propeller-shaped large conjugated aromatic amine system with excellent photochemical properties. Aromatic amine organic salts are a type of good infrared absorbing organic matter, which can give the coating good infrared absorption performance.

[0077] Test Example 3:

[0078] Self-healing performance test

[0079] Test method: Prepare infrared shielding coating according to the preparation method of coating in Test Example 1, use a blade to scratch a crack on the coating surface, the crack width is 0.1mm, the depth is 1.5mm, and after placing it in an environment of 80℃ for 24h, refer to the standard GB / T1771-2007, place the coating in a YWX_60 salt spray box, the salt spray is a 5% NaCl solution by mass, its pH is 6.5-7.2, the temperature is set to 35°C, the test time is 200h, observe the appearance of the coating after 200h, record whether there are blistering, cracking, rust and other phenomena, and observe the appearance of the scratch. The results are shown in Table 3.

[0080] Table 3

[0081] Appearance of scratches after self-repair Appearance of scratches after self-repair Example 1 No blistering, cracking or rusting Comparative Example 1 Rust in scratched areas Example 2 No blistering, cracking or rusting Comparative Example 2 No blistering, cracking or rusting Example 3 No blistering, cracking or rusting Comparative Example 3 No blistering, cracking or rusting Comparative Example 4 No blistering, cracking or rusting

[0082] From the comparison of the experimental data of Examples 1 to 3 and Comparative Examples 1 to 4 in Table 3, it can be found that the infrared shielding coating prepared by the present invention has good self-repairing performance.

[0083] By comparison, the coating appearance of Examples 1 to 3 is better than that of Comparative Example 1, indicating that after the polyvinyl chloride is pretreated with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, it reacts with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, then reacts with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, and then reacts with silver hexafluoride antimonate to obtain modified polyvinyl chloride; the polyvinyl chloride molecule contains a strongly polar C-Cl bond, which can undergo nucleophilic substitution with the amino group on the 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl free radical, so that the polyvinyl chloride is grafted with a nitroxide free radical, and the nitroxide free radical reacts with the symmetrical ketone 4,4'-diaminobenzophenone to form an alkoxyamine bond, and an aminophenyl is grafted on the polyvinyl chloride side chain. The alkoxyamine bond can undergo alkoxyamine bond cleavage and recombination under certain conditions, and the free radicals generated by the cleavage can undergo exchange reactions. This dynamic exchange property can give the coating formed by the coating a self-healing property.

[0084] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An infrared shielding coating, characterized in that: The infrared shielding coating comprises the following raw materials in parts by mass: 100 parts of modified polyvinyl chloride, 10-15 parts of silicon crown ether, 10-12 parts of modified cobalt blue, and 3-5 parts of chloroplatinic acid; The modified polyvinyl chloride is obtained by pre-treating polyvinyl chloride with 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical, reacting with 4,4'-diaminobenzophenone to obtain aminophenyl polyvinyl chloride, reacting with 4-iodostyrene to obtain triphenylamino polyvinyl chloride, and reacting with silver hexafluoride antimonate; The modified cobalt blue is obtained by polymerizing aniline on the surface of cobalt blue pretreated with a silane coupling agent and then grafting 1-(chloro-methylphosphinoyl)ethylene.

2. A method for preparing an infrared shielding coating according to claim 1, characterized in that: The preparation method comprises the following steps: (1) Polyvinyl chloride, 4-amino-2,2,6,6-tetramethylpiperidin-1-oxyl free radical and N,N-dimethylformamide are uniformly mixed in a mass ratio of 1:(0.3-0.5):(50-60), heated to 50-60°C and stirred for 2 hours, then cooled to room temperature and stirred for 3-4 hours, and vacuum rotary evaporation is performed to remove N,N-dimethylformamide to obtain pretreated polyvinyl chloride; (2) Pretreated polyvinyl chloride, 4,4'-diaminobenzophenone and tetrahydrofuran are mixed in a mass ratio of 1:(2-3):(50-60), and a 30wt% hydrogen peroxide solution of 0.4 times the volume of tetrahydrofuran is added dropwise at 5-10°C, and then cuprous chloride of 0.03 times the mass of polyvinyl chloride is added, and the temperature is raised to 20-30°C. After reacting for 24 hours, tetrahydrofuran is removed by vacuum rotary evaporation to obtain aminophenyl polyvinyl chloride; aminophenyl polyvinyl chloride, 4-iodostyrene, potassium carbonate and tetrahydrofuran are mixed in a mass ratio of 1:(5-6):(1-2):(20-30), and the reaction is performed for 5-6 hours. After the reaction is completed, the mixture is cooled to room temperature, and tetrahydrofuran is removed by vacuum rotary evaporation to obtain triphenylamine polyvinyl chloride; (3) Mix triphenylamine polyvinyl chloride, silver hexafluoride antimonate, and tetrahydrofuran in a mass ratio of 1:(2-3):(20-30), stir for 2-3 hours in a dark environment, filter and retain the filtrate, and remove tetrahydrofuran by vacuum rotary evaporation to obtain modified polyvinyl chloride; (4) At 0-2°C, ultrasonically mix the pretreated cobalt blue and 2 wt% polyvinyl pyrrolidone aqueous solution for 30 min, add hydrochloric acid aqueous solution and aniline, stir for 3-4 h at a stirring speed of 500 r / min, add ammonium persulfate and continue stirring for 3-4 h, filter and wash with anhydrous ethanol 3-4 times, and dry at 60°C for 6-8 h to obtain pre-modified cobalt blue; (5) Pre-modified cobalt blue, 1-(chloro-methylphosphinoyl)ethylene and 1,2-dichloroethane were mixed in a mass ratio of 1:(0.5-0.7):(50-60), heated to 87-92°C and refluxed for 10-12 hours, pure water equal in volume to 1,2-dichloroethane was added and stirred for 3 minutes, filtered and washed with pure water for 3-4 times, and dried at 60°C for 6-8 hours to obtain modified cobalt blue; (6) Weigh the following raw materials: modified polyvinyl chloride, modified cobalt blue, silicon crown ether, and chloroplatinic acid, put the above raw materials into a high-speed mixer and mix them for 5 minutes, then put them into a twin-screw extruder for melt extrusion, use a pelletizer to pelletize after extrusion, grind them with a grinder, and pass them through a 180-mesh sieve to obtain an infrared shielding coating.

3. The method for preparing an infrared shielding coating according to claim 2, characterized in that: The preparation method of the pretreated cobalt blue in step (4) is as follows: cobalt blue, silane coupling agent and anhydrous ethanol are mixed in a mass ratio of 1:(5-6):(100-120), ultrasonically oscillated for 20-30 minutes, heated to 40°C, stirred for 1-2 hours, filtered and washed with anhydrous ethanol for 3-4 times, and dried at 60°C for 6-8 hours to obtain the pretreated cobalt blue.

4. The method for preparing an infrared shielding coating according to claim 2, characterized in that: In step (4), the pretreated cobalt blue, aniline, 2 wt% polyvinyl pyrrolidone aqueous solution, 0.6 mol / L hydrochloric acid aqueous solution, and ammonium persulfate are weighed in a mass ratio of 1:1:(50-60):(25-30):(0.3-0.5).

5. The method for preparing an infrared shielding coating according to claim 2, characterized in that: The preparation method of the silicon crown ether in step (6) is as follows: weigh tri(4-methoxyphenyl)silane and boron tribromide in a molar ratio of 1:5; mix tri(4-methoxyphenyl)silane and dichloromethane in a mass ratio of 1:20 to obtain a silane solution; mix boron tribromide and dichloromethane in a mass ratio of 1:20 to obtain a boron tribromide solution; under nitrogen protection, at -52°C, drop the boron tribromide solution into the silane solution and start stirring, the dropping speed is 0.5mL / min, the stirring speed is 150r / min, add 10wt% dilute sulfuric acid 3 times the mass of boron tribromide, stir for 3min, filter and vacuum dry for 12h to obtain tri(4-phenolic hydroxyphenyl)silane; weigh tri(4-phenolic hydroxyphenyl)silane and diethylene glycol di-p-toluenesulfonate in a molar ratio of 1:1.4, under nitrogen protection, add tri(4-phenolic hydroxyphenyl)silane The mixture was stirred for 30 min at a mass ratio of 1:0.3:35, potassium hydroxide and tetrahydrofuran were added and stirred for 30 min at a speed of 150 r / min, and potassium hydroxide with a mass ratio of 0.3 times that of tri(4-phenolhydroxyphenyl)silane was added again, and stirring was continued for 30 min to obtain a phenolic hydroxysilane solution, diethylene glycol di-p-toluenesulfonate and tetrahydrofuran were mixed at a mass ratio of 1:35 to obtain a sulfonate solution, and the sulfonate solution was added dropwise to the phenolic hydroxysilane solution at a dropping speed of 0.5 mL / min. After the addition was completed, the temperature was raised to 72°C for reflux reaction and stirred for 36 h at a stirring speed of 150 r / min. After the stirring was completed, the tetrahydrofuran was removed by vacuum rotary evaporation to obtain a silyl crown ether; the silyl crown ether, manganese nitrate and methanol were mixed at a mass ratio of 1:0.7:10, stirred at 50°C for 2 h, and the methanol was removed by vacuum rotary evaporation to obtain a silicon crown ether.

6. The method for preparing an infrared shielding coating according to claim 2, characterized in that: The weighed amounts of the raw materials in step (6) are: by mass, 100 parts of modified polyvinyl chloride, 10-15 parts of silicon crown ether, 10-12 parts of modified cobalt blue, and 3-5 parts of chloroplatinic acid; the temperature of the twin-screw extruder is 120°C.

7. The method for preparing an infrared shielding coating according to claim 2, characterized in that: The polyvinyl chloride model in step (1) is SG-8.

8. The method for preparing an infrared shielding coating according to claim 3, characterized in that: The silane coupling agent is (3-trimethoxysilyl propoxy) aniline; the cobalt blue model is B2805.