Water-based UV-curable heat-insulating coating and preparation method thereof

Abstract

The invention discloses a water-based UV curing thermal insulation coating and a preparation method thereof, the coating comprises the following raw materials by weight: 50-60 parts of modified polyurethane, 5-8 parts of a modified filler, 5-8 parts of a thermal insulation filler, 30-35 parts of isobornyl acrylate, 2-3 parts of a photoinitiator and 40-50 parts of deionized water, the molecular chain of the modified polyurethane and the molecular chain end point all contain unsaturated double bonds, the surfaces of the heat-insulating filler and the modified filler also contain unsaturated double bonds, under the action of the photoinitiator, the modified polyurethane, the modified filler, the heat-insulating filler and the isobornyl acrylate are polymerized to form a large number of crosslinking sites, the water resistance of the coating can be improved, and meanwhile, the surfaces of the modified filler and the heat-insulating filler contain polysiloxane structures, so that the water resistance of the coating is improved. Pores in the heat-insulating filler contain argon, and the argon has a good heat-insulating effect, so that the coating has a good heat-insulating effect when being matched with a layered structure of hexagonal boron nitride.

Description

Technical Field

[0001] The invention relates to the technical field of UV curing coating preparation, and in particular to a water-based UV curing thermal insulation coating and a preparation method thereof. Background Art

[0002] As a new type of coating, UV curing coating uses ultraviolet light to initiate cross-linking reaction, does not require solvents, has the advantages of fast curing speed, good environmental performance, high coating hardness, good gloss, etc., and is widely used in various fields. In the field of construction, UV curing coating can also improve the thermal insulation and heat preservation of buildings. Commonly used thermal insulation coatings include reflective thermal insulation coatings, barrier thermal insulation coatings, radiation thermal insulation coatings, composite thermal insulation coatings, etc. Regardless of the type of coating, in the context of increasingly stringent environmental protection, the development of environmentally friendly thermal insulation coatings is very important, so a large number of water-based UV curing coatings have emerged, but traditional water-based coatings have the problems of single performance, poor thermal insulation effect, and poor water resistance, resulting in a limited scope of application of the coating and inconvenience for promotion. Summary of the invention

[0003] The purpose of the present invention is to provide a water-based UV curing thermal insulation coating and a preparation method thereof, which solves the problem that the current water-based UV curing coating has poor thermal insulation effect and poor water resistance.

[0004] The purpose of the present invention can be achieved through the following technical solutions:

[0005] A method for preparing a water-based UV-curable thermal insulation coating comprises the following steps:

[0006] Step A1: pentaerythritol, acryloyl chloride, potassium carbonate and deionized water are mixed, and reacted for 2-3 hours at a speed of 200-300 r / min and a temperature of 25-30° C. to obtain a modifier; octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide, tetramethyldisiloxane and dimethyl sulfoxide are mixed uniformly, and nitrogen is introduced for protection, and reacted for 10-15 hours at a speed of 120-150 r / min and a temperature of 90-95° C., and the temperature is raised to 105-110° C. and the reaction is continued for 2-3 hours to obtain dihydrogenpolysiloxane;

[0007] Step A2: Dihydrogen polysiloxane, a modifier, chloroplatinic acid and DMF are mixed evenly, and reacted for 3-5 hours at a speed of 120-150 r / min and a temperature of 60-70° C. to obtain a functional monomer; nano-silica is dispersed in ethanol, and stirred at a speed of 200-300 r / min and a temperature of 60-70° C., and deionized water and KH550 are added to react for 2-3 hours to obtain modified silica; modified silica, functional monomer and DMF are mixed evenly, and reacted for 2-3 hours at a speed of 200-300 r / min, a temperature of 30-40° C. and a pH value of 11-12 to obtain a modified filler;

[0008] Step A3: Toluene diisocyanate, polyether diol, castor oil and dibutyltin dilaurate are mixed, and the reaction is carried out for 3-4 hours at a rotation speed of 120-150 r / min and a temperature of 80-85° C., dihydroxymethylpropionic acid is added, and the reaction is continued for 2-3 hours, and the temperature is lowered to 70-75° C., hydroxyethyl methacrylate is added, and the reaction is continued for 2-3 hours, and the temperature is lowered to 40-50° C., triethylamine is added, and the reaction is carried out for 30-40 minutes to obtain a modified polyurethane, and the following raw materials are weighed in parts by weight: 50-60 parts of modified polyurethane, 5-8 parts of modified filler, 5-8 parts of thermal insulation filler, 30-35 parts of isobornyl acrylate, 2-3 parts of photoinitiator and 40-50 parts of deionized water, and the raw materials are mixed evenly to obtain a water-based UV-curable thermal insulation coating.

[0009] Furthermore, the molar ratio of pentaerythritol, acryloyl chloride and potassium carbonate in step A1 is 1:4:4.2, and the molar ratio of octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide and tetramethyldisiloxane is 2.4:0.2:3:4.

[0010] Furthermore, the molar ratio of the dihydrogenpolysiloxane and the modifier in step A2 is 1:2, the amount of chloroplatinic acid is 1‰ of the mass of the dihydrogenpolysiloxane, the amount of KH550 is 2% of the mass of the nano-silica, and the mass ratio of the modified silica and the functional monomer is 1:3.

[0011] Furthermore, the molar ratio of toluene diisocyanate, polyether diol, castor oil, dimethylolpropionic acid, hydroxyethyl methacrylate and triethylamine described in step A3 is 6:3:1:1:1.2:1, and the amount of dibutyltin dilaurate is 3‰ of the mass of toluene diisocyanate.

[0012] Furthermore, the thermal insulation filler is made by the following steps:

[0013] Step B1: mixing carbon nanotubes and mixed acid, reacting for 3-5 hours at a speed of 60-80 r / min and a temperature of 100-110° C., washing with deionized water until neutral to obtain carboxylated carbon nanotubes, and uniformly mixing carboxylated carbon nanotubes, melamine, dicyclohexylcarbodiimide and pyridine, reacting for 2-3 hours at a speed of 150-200 r / min and a temperature of 25-30° C. to obtain pre-treated carbon nanotubes;

[0014] Step B2: Pretreated carbon nanotubes, melamine and deionized water are mixed uniformly, stirred and added with boric acid at a speed of 600-800 r / min and a temperature of 25-30°C, reacted for 3-5 hours, and then the deionized water is removed by distillation. The substrate is added into a tube furnace, heated to 800-850°C at an argon atmosphere at a heating rate of 5°C / min, ammonia is introduced, and the heat treatment is carried out for 5-6 hours to obtain a precursor, the precursor is mixed with a sodium hydroxide solution, and refluxed at a temperature of 120-125°C for 20-25 hours to obtain a hydroxylated precursor;

[0015] Step B3: Place the hydroxylated precursor in a reaction kettle, introduce argon to expel the air, maintain the pressure at 120-130 kPa, and after maintaining the pressure for 2-3 hours, add methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water, and react at a speed of 600-800 r / min and a temperature of 40-50°C for 2-3 hours, filter and remove the filtrate, and keep the filter cake at a temperature of 120-125°C for 3-5 hours to obtain a modified filler.

[0016] Furthermore, the carbon nanotubes and the mixed acid in step B1 are used in a ratio of 1 g:80 mL, the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the molar ratio of carboxyl groups on the carboxylated carbon nanotubes, melamine and dicyclohexylcarbodiimide is 1:1:1.1.

[0017] Furthermore, the mass ratio of the pretreated carbon nanotubes, melamine and boric acid in step B2 is 1:2.2:3, the amount ratio of the precursor and the sodium hydroxide solution is 1 g:100 mL, and the concentration of the sodium hydroxide solution is 5 mol / L.

[0018] Furthermore, the dosage ratio of the hydroxylated precursor, methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water in step B3 is 1 g: 2 mL: 5 mL: 20 mL.

[0019] Beneficial effects of the present invention: A water-based UV-curable thermal insulation coating prepared by the present invention comprises the following raw materials: modified polyurethane, modified filler, thermal insulation filler, isobornyl acrylate, photoinitiator and deionized water. The modified polyurethane is prepared by using polyether diol and castor oil as raw materials to prepare a polyurethane prepolymer, which is chain extended with dihydroxymethylpropionic acid, then end-capped with hydroxyethyl methacrylate, and finally neutralized with triethylamine to prepare the modified polyurethane.

[0020] The modified filler uses pentaerythritol and acryloyl chloride as raw materials, and the hydroxyl group on the pentaerythritol reacts with the acyl chloride group on the acryloyl chloride to obtain a modifier, and octamethylcyclotetrasiloxane is ring-opened and polymerized with 3-glycidyloxypropylmethyldiethoxysilane and tetramethyldisiloxane to obtain dihydrogenpolysiloxane, and the dihydrogenpolysiloxane is reacted with the modifier to graft the SiH bond on the dihydrogenpolysiloxane with the double bond on the modifier to form a double bond end capping to obtain a functional monomer, and nano-silica is treated with KH550 to graft amino groups on the surface to obtain modified silica, and the modified silica and the functional monomer are reacted under alkaline conditions to react the amino groups on the modified silica with the epoxy groups on the functional monomer to obtain the modified filler.

[0021] The heat-insulating filler is made of carbon nanotubes as raw materials and treated with mixed acid to obtain carboxylated carbon nanotubes. The carbon nanotubes and melamine are reacted so that the carboxyl groups on the carboxylated carbon nanotubes react with the amino groups on the melamine, so that the amino groups are grafted on the surface to obtain pretreated carbon nanotubes. The pretreated carbon nanotubes, melamine and boric acid are reacted and kept warm at high temperature to form a hexagonal boron nitride structure on the surface to obtain a hydroxylated precursor. The hydroxylated precursor is placed in an argon atmosphere and pressure is maintained so that the pores on the hydroxylated precursor are filled with argon. Methacryloxypropyl trimethoxysilane, tetramethyl silicate and deionized water are then added, and the methacryloxypropyl trimethoxysilane and tetramethyl silicate are hydrolyzed and hydrolyzed and condensed on the surface of the hydroxylated precursor. Finally, the surface is kept warm at high temperature to form an organic silicone resin coating.

[0022] The modified polyurethane in the UV coating contains unsaturated double bonds in the molecular chain and at the molecular chain endpoints, and the thermal insulation filler and the surface of the modified filler also contain unsaturated double bonds. Under the action of a photoinitiator, the modified polyurethane, the modified filler, the thermal insulation filler and the isobornyl acrylate are polymerized to form a large number of cross-linking sites, which can increase the water resistance of the coating. At the same time, the surface of the modified filler and the thermal insulation filler contains a polysiloxane structure, which further improves the water resistance effect. The pores in the thermal insulation filler contain argon, which has a good thermal insulation effect. Combined with the layered structure of hexagonal boron nitride, the thermal insulation effect of the coating is greatly improved. At the same time, the surface is coated with a polysiloxane layer, which can prevent the leakage of argon and ensure the durability of the thermal insulation effect. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Embodiment 1: A method for preparing a water-based UV-curable thermal insulation coating, comprising the following steps:

[0025] Step A1: pentaerythritol, acryloyl chloride, potassium carbonate and deionized water are mixed, and reacted for 2 hours at a speed of 200 r / min and a temperature of 25° C. to obtain a modifier; octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide, tetramethyldisiloxane and dimethyl sulfoxide are mixed uniformly, and nitrogen is introduced for protection, and reacted for 10 hours at a speed of 120 r / min and a temperature of 90° C., and the temperature is raised to 105° C. and the reaction is continued for 2 hours to obtain dihydrogenpolysiloxane;

[0026] Step A2: Dihydrogen polysiloxane, a modifier, chloroplatinic acid and DMF are mixed evenly, and reacted for 3 hours at a speed of 120 r / min and a temperature of 60° C. to obtain a functional monomer; nano-silica is dispersed in ethanol, and stirred at a speed of 200 r / min and a temperature of 60° C., and deionized water and KH550 are added to react for 2 hours to obtain modified silica; modified silica, functional monomer and DMF are mixed evenly, and reacted for 2 hours at a speed of 200 r / min, a temperature of 30° C. and a pH value of 11 to obtain a modified filler;

[0027] Step A3: Toluene diisocyanate, polyether diol, castor oil and dibutyltin dilaurate are mixed, and the reaction is carried out for 3 hours at a speed of 120 r / min and a temperature of 80°C. Dimethylolpropionic acid is added, and the reaction is continued for 2 hours. The temperature is lowered to 70°C, hydroxyethyl methacrylate is added, and the reaction is continued for 2 hours. The temperature is lowered to 40°C, triethylamine is added, and the reaction is carried out for 30 minutes to obtain a modified polyurethane. The following raw materials are weighed in parts by weight: 50 parts of modified polyurethane, 5 parts of modified filler, 5 parts of thermal insulation filler, 30 parts of isobornyl acrylate, 2 parts of photoinitiator and 40 parts of deionized water. The raw materials are mixed evenly to obtain a water-based UV-curing thermal insulation coating.

[0028] The molar ratio of pentaerythritol, acryloyl chloride and potassium carbonate in step A1 is 1:4:4.2, and the molar ratio of octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide and tetramethyldisiloxane is 2.4:0.2:3:4.

[0029] The molar ratio of dihydrogenpolysiloxane and the modifier described in step A2 is 1:2, the amount of chloroplatinic acid is 1‰ of the mass of dihydrogenpolysiloxane, the amount of KH550 is 2% of the mass of nano-silica, and the mass ratio of modified silica and functional monomer is 1:3.

[0030] The molar ratio of toluene diisocyanate, polyether diol, castor oil, dimethylolpropionic acid, hydroxyethyl methacrylate and triethylamine described in step A3 is 6:3:1:1:1.2:1, the amount of dibutyltin dilaurate is 3‰ of the mass of toluene diisocyanate, the model of polyether diol is DL-400, and the model of photoinitiator is 1173.

[0031] The thermal insulation filler is made by the following steps:

[0032] Step B1: mixing carbon nanotubes and mixed acid, reacting for 3 hours at a speed of 60 r / min and a temperature of 100° C., washing with deionized water until neutral to obtain carboxylated carbon nanotubes, and uniformly mixing carboxylated carbon nanotubes, melamine, dicyclohexylcarbodiimide and pyridine, reacting for 2 hours at a speed of 150 r / min and a temperature of 25° C. to obtain pre-treated carbon nanotubes;

[0033] Step B2: Pretreated carbon nanotubes, melamine and deionized water are mixed uniformly, stirred and boric acid is added at a speed of 600 r / min and a temperature of 25°C, and the reaction is carried out for 3 hours, and the deionized water is removed by distillation, and the substrate is added into a tube furnace, and the temperature is increased to 800°C at an argon atmosphere at a heating rate of 5°C / min, and ammonia is introduced, and the heat treatment is carried out for 5 hours to obtain a precursor, and the precursor is mixed with a sodium hydroxide solution, and refluxed at a temperature of 120°C for 20 hours to obtain a hydroxylated precursor;

[0034] Step B3: Place the hydroxylated precursor in a reaction kettle, introduce argon gas to expel the air, maintain the pressure at 120 kPa, and after maintaining the pressure for 2 hours, add methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water, and react at a speed of 600 r / min and a temperature of 40°C for 2 hours. Filter and remove the filtrate, and keep the filter cake at a temperature of 120°C for 3 hours to obtain a modified filler.

[0035] The amount ratio of the carbon nanotubes and the mixed acid in step B1 is 1 g:80 mL, the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the molar ratio of the carboxyl groups on the carboxylated carbon nanotubes, melamine and dicyclohexylcarbodiimide is 1:1:1.1.

[0036] The mass ratio of the pretreated carbon nanotubes, melamine and boric acid in step B2 is 1:2.2:3, the amount ratio of the precursor and the sodium hydroxide solution is 1g:100mL, and the concentration of the sodium hydroxide solution is 5mol / L.

[0037] The dosage ratio of the hydroxylated precursor, methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water described in step B3 is 1 g: 2 mL: 5 mL: 20 mL.

[0038] Embodiment 2: A method for preparing a water-based UV-curable thermal insulation coating, comprising the following steps:

[0039] Step A1: pentaerythritol, acryloyl chloride, potassium carbonate and deionized water are mixed, and reacted for 2 hours at a speed of 200 r / min and a temperature of 30° C. to obtain a modifier; octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide, tetramethyldisiloxane and dimethyl sulfoxide are mixed uniformly, and nitrogen is introduced for protection, and reacted for 15 hours at a speed of 120 r / min and a temperature of 95° C., and the temperature is raised to 105° C. and the reaction is continued for 3 hours to obtain dihydrogenpolysiloxane;

[0040] Step A2: Dihydrogen polysiloxane, a modifier, chloroplatinic acid and DMF are mixed evenly, and reacted for 4 hours at a speed of 120 r / min and a temperature of 65° C. to obtain a functional monomer; nano-silica is dispersed in ethanol, and stirred at a speed of 300 r / min and a temperature of 65° C., and deionized water and KH550 are added to react for 2 hours to obtain modified silica; modified silica, functional monomer and DMF are mixed evenly, and reacted for 3 hours at a speed of 300 r / min, a temperature of 30-40° C. and a pH value of 11 to obtain a modified filler;

[0041] Step A3: Toluene diisocyanate, polyether diol, castor oil and dibutyltin dilaurate are mixed, and the reaction is carried out for 3 hours at a speed of 150 r / min and a temperature of 80°C. Dimethylolpropionic acid is added, and the reaction is continued for 3 hours. The temperature is lowered to 70°C, hydroxyethyl methacrylate is added, and the reaction is continued for 2 hours. The temperature is lowered to 45°C, triethylamine is added, and the reaction is carried out for 35 minutes to obtain a modified polyurethane. The following raw materials are weighed in parts by weight: 55 parts of modified polyurethane, 6 parts of modified filler, 7 parts of thermal insulation filler, 33 parts of isobornyl acrylate, 2.5 parts of photoinitiator and 45 parts of deionized water. The raw materials are mixed evenly to obtain a water-based UV-curing thermal insulation coating.

[0042] The molar ratio of pentaerythritol, acryloyl chloride and potassium carbonate in step A1 is 1:4:4.2, and the molar ratio of octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide and tetramethyldisiloxane is 2.4:0.2:3:4.

[0043] The molar ratio of dihydrogenpolysiloxane and the modifier described in step A2 is 1:2, the amount of chloroplatinic acid is 1‰ of the mass of dihydrogenpolysiloxane, the amount of KH550 is 2% of the mass of nano-silica, and the mass ratio of modified silica and functional monomer is 1:3.

[0044] The molar ratio of toluene diisocyanate, polyether diol, castor oil, dimethylolpropionic acid, hydroxyethyl methacrylate and triethylamine described in step A3 is 6:3:1:1:1.2:1, the amount of dibutyltin dilaurate is 3‰ of the mass of toluene diisocyanate, the model of polyether diol is DL-400, and the model of photoinitiator is 2959.

[0045] The thermal insulation filler is made by the following steps:

[0046] Step B1: mixing carbon nanotubes and mixed acid, reacting for 4 hours at a speed of 60 r / min and a temperature of 105° C., washing with deionized water until neutral to obtain carboxylated carbon nanotubes, and uniformly mixing carboxylated carbon nanotubes, melamine, dicyclohexylcarbodiimide and pyridine, reacting for 2 hours at a speed of 200 r / min and a temperature of 25° C. to obtain pre-treated carbon nanotubes;

[0047] Step B2: Pretreated carbon nanotubes, melamine and deionized water are mixed uniformly, stirred and boric acid is added at a speed of 800 r / min and a temperature of 25°C, and the reaction is carried out for 4 hours. The deionized water is removed by distillation, and the substrate is added into a tube furnace. Under an argon atmosphere with a heating rate of 5°C / min, the temperature is increased to 830°C, ammonia is introduced, and the temperature is kept for 6 hours to obtain a precursor. The precursor is mixed with a sodium hydroxide solution, and refluxed at a temperature of 120°C for 25 hours to obtain a hydroxylated precursor;

[0048] Step B3: Place the hydroxylated precursor in a reaction kettle, introduce argon gas to expel the air, maintain the pressure at 125 kPa, and after maintaining the pressure for 2 hours, add methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water, and react at a speed of 600 r / min and a temperature of 45°C for 3 hours. Filter and remove the filtrate, and keep the filter cake at a temperature of 120°C for 4 hours to obtain a modified filler.

[0049] The amount ratio of the carbon nanotubes and the mixed acid in step B1 is 1 g:80 mL, the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the molar ratio of the carboxyl groups on the carboxylated carbon nanotubes, melamine and dicyclohexylcarbodiimide is 1:1:1.1.

[0050] The mass ratio of the pretreated carbon nanotubes, melamine and boric acid in step B2 is 1:2.2:3, the amount ratio of the precursor and the sodium hydroxide solution is 1g:100mL, and the concentration of the sodium hydroxide solution is 5mol / L.

[0051] The dosage ratio of the hydroxylated precursor, methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water described in step B3 is 1 g: 2 mL: 5 mL: 20 mL.

[0052] Embodiment 3: A method for preparing a water-based UV-curable thermal insulation coating, comprising the following steps:

[0053] Step A1: pentaerythritol, acryloyl chloride, potassium carbonate and deionized water are mixed, and reacted at a speed of 300 r / min and a temperature of 30° C. for 3 hours to obtain a modifier; octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide, tetramethyldisiloxane and dimethyl sulfoxide are mixed uniformly, and nitrogen is introduced for protection, and reacted at a speed of 150 r / min and a temperature of 95° C. for 15 hours, and the temperature is raised to 110° C. and the reaction is continued for 3 hours to obtain dihydrogenpolysiloxane;

[0054] Step A2: Dihydrogen polysiloxane, a modifier, chloroplatinic acid and DMF are mixed evenly, and reacted for 5 hours at a speed of 150 r / min and a temperature of 70° C. to obtain a functional monomer; nano-silica is dispersed in ethanol, and stirred at a speed of 300 r / min and a temperature of 70° C., and deionized water and KH550 are added to react for 3 hours to obtain modified silica; modified silica, functional monomer and DMF are mixed evenly, and reacted for 3 hours at a speed of 300 r / min, a temperature of 40° C. and a pH value of 12 to obtain a modified filler;

[0055] Step A3: Toluene diisocyanate, polyether diol, castor oil and dibutyltin dilaurate are mixed, and the reaction is carried out for 4 hours at a speed of 150 r / min and a temperature of 85°C. Dimethylolpropionic acid is added, and the reaction is continued for 3 hours. The temperature is lowered to 75°C, hydroxyethyl methacrylate is added, and the reaction is continued for 3 hours. The temperature is lowered to 50°C, triethylamine is added, and the reaction is carried out for 40 minutes to obtain a modified polyurethane. The following raw materials are weighed in parts by weight: 60 parts of modified polyurethane, 8 parts of modified filler, 8 parts of thermal insulation filler, 35 parts of isobornyl acrylate, 3 parts of photoinitiator and 50 parts of deionized water. The raw materials are mixed evenly to obtain a water-based UV-curing thermal insulation coating.

[0056] The molar ratio of pentaerythritol, acryloyl chloride and potassium carbonate in step A1 is 1:4:4.2, and the molar ratio of octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide and tetramethyldisiloxane is 2.4:0.2:3:4.

[0057] The molar ratio of dihydrogenpolysiloxane and the modifier described in step A2 is 1:2, the amount of chloroplatinic acid is 1‰ of the mass of dihydrogenpolysiloxane, the amount of KH550 is 2% of the mass of nano-silica, and the mass ratio of modified silica and functional monomer is 1:3.

[0058] The molar ratio of toluene diisocyanate, polyether diol, castor oil, dimethylolpropionic acid, hydroxyethyl methacrylate and triethylamine described in step A3 is 6:3:1:1:1.2:1, the amount of dibutyltin dilaurate is 3‰ of the mass of toluene diisocyanate, the model of polyether diol is DL-400, and the model of photoinitiator is 184.

[0059] The thermal insulation filler is made by the following steps:

[0060] Step B1: mixing carbon nanotubes and mixed acid, reacting for 5 hours at a speed of 80 r / min and a temperature of 110° C., washing with deionized water until neutral to obtain carboxylated carbon nanotubes, and uniformly mixing carboxylated carbon nanotubes, melamine, dicyclohexylcarbodiimide and pyridine, reacting for 3 hours at a speed of 200 r / min and a temperature of 30° C. to obtain pre-treated carbon nanotubes;

[0061] Step B2: Pretreated carbon nanotubes, melamine and deionized water are mixed uniformly, stirred and added with boric acid at a speed of 800 r / min and a temperature of 30°C, reacted for 5 hours, and then the deionized water is removed by distillation. The substrate is added into a tube furnace, heated to 850°C at an argon atmosphere at a heating rate of 5°C / min, ammonia is introduced, and the heat treatment is carried out for 6 hours to obtain a precursor, the precursor is mixed with a sodium hydroxide solution, and refluxed at a temperature of 125°C for 25 hours to obtain a hydroxylated precursor;

[0062] Step B3: Place the hydroxylated precursor in a reaction kettle, introduce argon gas to expel the air, maintain the pressure at 130 kPa, and after maintaining the pressure for 3 hours, add methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water, and react at a speed of 800 r / min and a temperature of 50°C for 3 hours. Filter and remove the filtrate, and keep the filter cake at a temperature of 125°C for 5 hours to obtain a modified filler.

[0063] The amount ratio of the carbon nanotubes and the mixed acid in step B1 is 1 g:80 mL, the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the molar ratio of the carboxyl groups on the carboxylated carbon nanotubes, melamine and dicyclohexylcarbodiimide is 1:1:1.1.

[0064] The mass ratio of the pretreated carbon nanotubes, melamine and boric acid in step B2 is 1:2.2:3, the amount ratio of the precursor and the sodium hydroxide solution is 1g:100mL, and the concentration of the sodium hydroxide solution is 5mol / L.

[0065] The dosage ratio of the hydroxylated precursor, methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water described in step B3 is 1 g: 2 mL: 5 mL: 20 mL.

[0066] Comparative Example 1: Compared with Example 1, no modified filler was added to this comparative example, and the remaining steps were the same.

[0067] Comparative Example 2: Compared with Example 1, this comparative example uses nano-silicon dioxide instead of the modified filler, and the other steps are the same.

[0068] Comparative Example 3: Compared with Example 1, this comparative example uses hexagonal boron nitride instead of the thermal insulation filler, and the remaining steps are the same.

[0069] Comparative Example 4: Compared with Example 1, this comparative example uses carbon nanotubes instead of the hydroxylated precursor, and the remaining steps are the same.

[0070] Comparative Example 5: Compared with Example 1, methacryloxypropyltrimethoxysilane was not added in this comparative example, and the remaining steps were the same.

[0071] The heat-insulating coatings prepared in Examples 1-3 and Comparative Examples 1-5 were applied to tinplates (330×300×3mm) of the same specifications to form a coating with a thickness of about 200 μm; the tinplate was then placed vertically at the opening of a muffle furnace at about 250°C, with the coating facing away from the muffle furnace. The temperature of the coating was tested using an infrared thermometer, and the test temperature at the beginning of the treatment was recorded as T1; after 15 minutes of treatment, the temperature difference was calculated as T2. According to the standard of GB / T1733-1993, the paint film was observed after immersion for 96 hours at a temperature of 25°C. The test results are shown in Table 1 below.

[0072]

[0073] It can be seen from the above table that the present application has good heat insulation and water resistance effects.

[0074] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the concept of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a water-based UV-curable thermal insulation coating, characterized in that: The specific steps include: Step A1: pentaerythritol, acryloyl chloride, potassium carbonate and deionized water are mixed to react to obtain a modifier, octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide, tetramethyldisiloxane and dimethyl sulfoxide are mixed uniformly, nitrogen is introduced for protection, and the mixture is reacted to obtain dihydrogenpolysiloxane; Step A2: dihydrogen polysiloxane, a modifier, chloroplatinic acid and DMF are mixed and reacted to obtain a functional monomer, nano-silica is dispersed in ethanol, stirred and deionized water and KH550 are added to react to obtain modified silica, and the modified silica, the functional monomer and DMF are mixed and reacted to obtain a modified filler; Step A3: toluene diisocyanate, polyether diol, castor oil and dibutyltin dilaurate are mixed, reacted, dimethylol propionic acid is added, the reaction is continued, the temperature is reduced and hydroxyethyl methacrylate is added, the reaction is continued, the temperature is reduced and triethylamine is added, and the reaction is carried out to obtain a modified polyurethane. The following raw materials are weighed in parts by weight: 50-60 parts of modified polyurethane, 5-8 parts of modified filler, 5-8 parts of thermal insulation filler, 30-35 parts of isobornyl acrylate, 2-3 parts of photoinitiator and 40-50 parts of deionized water, and the raw materials are mixed evenly to obtain a water-based UV-curable thermal insulation coating.

2. The method for preparing a water-based UV-curable thermal insulation coating according to claim 1, characterized in that: The molar ratio of pentaerythritol, acryloyl chloride and potassium carbonate in step A1 is 1:4:4.2, and the molar ratio of octamethylcyclotetrasiloxane, 3-glycidyloxypropylmethyldiethoxysilane, tetramethylammonium hydroxide and tetramethyldisiloxane is 2.4:0.2:3:

4.

3. The method for preparing a water-based UV-curable thermal insulation coating according to claim 1, characterized in that: The molar ratio of dihydrogen polysiloxane to the modifier in step A2 is 1:2, the amount of KH550 used is 2% of the mass of nano-silica, and the mass ratio of modified silica to the functional monomer is 1:

3.

4. The method for preparing a water-based UV-curable thermal insulation coating according to claim 1, characterized in that: The molar ratio of toluene diisocyanate, polyether diol, castor oil, dimethylolpropionic acid, hydroxyethyl methacrylate and triethylamine described in step A3 is 6:3:1:1:1.2:

1.

5. The method for preparing a water-based UV-curable thermal insulation coating according to claim 1, characterized in that: The thermal insulation filler is made by the following steps: Step B1: After the carbon nanotubes and the mixed acid are mixed and reacted, the mixture is washed with deionized water until it is neutral to obtain carboxylated carbon nanotubes, and the carboxylated carbon nanotubes, melamine, dicyclohexylcarbodiimide and pyridine are mixed and reacted to obtain pre-treated carbon nanotubes; Step B2: pretreated carbon nanotubes, melamine and deionized water are mixed and stirred and boric acid is added. After the reaction, the deionized water is removed by distillation, the substrate is added into a tube furnace, the temperature is increased and ammonia is introduced, and the heat is kept to obtain a precursor. The precursor is mixed with a sodium hydroxide solution and refluxed to obtain a hydroxylated precursor. Step B3: placing the hydroxylated precursor in a reaction kettle, introducing argon gas to expel the air, and after pressure treatment, adding methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water, reacting, filtering to remove the filtrate, and subjecting the filter cake to high-temperature insulation treatment to obtain a modified filler.

6. The method for preparing a water-based UV-curable thermal insulation coating according to claim 5, characterized in that: The amount ratio of the carbon nanotubes and the mixed acid in step B1 is 1 g:80 mL, the mixed acid is prepared by mixing concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1, and the molar ratio of the carboxyl groups on the carboxylated carbon nanotubes, melamine and dicyclohexylcarbodiimide is 1:1:1.

1.

7. The method for preparing a water-based UV-curable thermal insulation coating according to claim 5, characterized in that: The mass ratio of the pretreated carbon nanotubes, melamine and boric acid in step B2 is 1:2.2:3, and the amount ratio of the precursor and the sodium hydroxide solution is 1 g:100 mL.

8. The method for preparing a water-based UV-curable thermal insulation coating according to claim 5, characterized in that: The dosage ratio of the hydroxylated precursor, methacryloxypropyltrimethoxysilane, tetramethyl silicate and deionized water described in step B3 is 1 g: 2 mL: 5 mL: 20 mL.

9. A water-based UV-curable thermal insulation coating, characterized in that: Prepared according to any one of the preparation methods described in claims 1-8.

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