Self-cleaning polyurethane thermal insulation coating material for building surface and its preparation method

Abstract

The present application discloses a self-cleaning polyurethane thermal insulation coating material for building surfaces and a preparation method thereof, relating to coating material technology, including the following raw materials: oligomeric diol, aromatic diisocyanate, organic solvent, catalyst, modified organosilicon oligomer, modified nano-titanium dioxide particle solution; the molar ratio of the oligomeric diol to the aromatic diisocyanate is 1∶(3-5), and the mass ratio of the oligomeric diol to the modified organosilicon oligomer and the modified nano-titanium dioxide particle solution is 1∶(1-3)∶(1-1.5). The polyurethane thermal insulation coating material provided by the present application has superhydrophobic self-cleaning ability, effectively improving the self-cleaning effect and the durability of the coating.

Description

Technical Field

[0001] This application relates to the field of coating material technologies, and particularly to a self-cleaning polyurethane thermal insulation coating material for building surface applications and a preparation method thereof. Background Art

[0002] Polyurethane resin, as a polymer material with characteristics such as high strength, tear resistance, and wear resistance, is widely used in daily life, industrial and agricultural production, medicine and other fields, for heat insulation, cold insulation, and waterproofing of storage tanks, pipelines, cold storages, beer, fermentation tanks, fresh-keeping barrels, and for heat insulation and waterproofing of building exteriors, with excellent waterproof performance. Building exterior wall coatings can beautify the environment and living rooms. However, due to the poor scrub resistance of traditional coatings, the coating will change color and peel off after a short time. Glass curtain walls or ceramic tile facades will cause light pollution, increase the building's self-weight, and pose safety hazards. Moreover, as urban environmental pollution is intensifying, dust pollution and gas pollution are particularly serious. Building exteriors, especially high-rise buildings, are being eroded more and more severely. The role of self-cleaning coatings is becoming increasingly important. Self-cleaning coatings have excellent waterproof and self-cleaning functions and can remain clean for a long time.

[0003] The technical development of self-cleaning coatings in the prior art is based on the principle of bionics, and successful self-cleaning coatings have been developed based on the "lotus leaf self-cleaning principle"

[0004] For example, Chinese Patent with the authorization announcement number CN101962514B discloses a long-lasting superhydrophobic self-cleaning coating and a preparation method thereof. The coating material described in this invention is formed by room temperature curing and drying of photocatalytically active nanoparticles, a low surface free energy polymer, and a crosslinking agent. The low surface free energy polymer is composed of one or more of fluorinated polysiloxane, polydimethylsiloxane, and polymethylphenylsiloxane containing active groups such as hydroxyalkoxy, carbon-carbon double bond, silanol, or siloxy group. The crosslinking agent is hydrogen-containing silicone oil or amino silane, and the mass content of photocatalytic nanoparticles in the coating is between 10-60%. This coating forms a micro-nano structure by self-organization of nanoparticles, together with a crosslinked film matrix with a low surface energy, to obtain a superhydrophobic self-cleaning coating with a lotus leaf effect. The persistence of the lotus leaf type superhydrophobic property of the coating is achieved by using the photocatalytic decomposition characteristics of nanoparticles for organic pollutants. It is suitable for large-area construction, has good weather resistance, and has outstanding self-cleaning characteristics;

[0005] However, the main components of some current self-cleaning coatings are inorganic substances that provide a rough structure. However, inorganic nanoparticles often have a large specific surface area and high surface energy, tending to agglomerate easily, resulting in a decline in the performance of the coatings during use, a reduction in the flatness of the coating, and defects such as cracks and bubbles on the surface. At the same time, the compatibility between inorganic nanoparticles and resins is poor, and phase separation is likely to occur after mixing. Therefore, the self-cleaning polyurethane thermal insulation coating materials obtained have a poor self-cleaning effect and low durability. Summary of the Invention

[0006] In order to improve the self-cleaning effect and durability of self-cleaning polyurethane thermal insulation coating materials, the present application provides self-cleaning polyurethane thermal insulation coating materials for building surfaces and their preparation methods.

[0007] The self-cleaning polyurethane thermal insulation coating materials for building surfaces and their preparation methods provided by the present application adopt the following technical solutions:

[0008] The self-cleaning polyurethane thermal insulation coating materials for building surfaces and their preparation methods include the following raw materials: oligomeric diol, aromatic diisocyanate, organic solvent, catalyst, modified organosilicon oligomer, modified nano-titanium dioxide particle solution; the molar ratio of the oligomeric diol to the aromatic diisocyanate is 1:(3 - 5), and the mass ratio of the oligomeric diol to the modified organosilicon oligomer and the modified nano-titanium dioxide particle solution is 1:(1 - 3):(1 - 1.5).

[0009] By adopting the above technical solutions, a modified organosilicon oligomer is added during the preparation of the polyurethane coating. On the one hand, it can improve the properties of the polyurethane coating such as high temperature resistance and weather resistance, and enhance the durability of the coating. On the other hand, the modified organosilicon oligomer can increase the surface energy of the composite coating, thereby improving the hydrophobicity of the polyurethane coating. By further compounding the modified nano-titanium dioxide particle solution, under the action of light, electrons in the valence band of the photocatalytic material nano-titanium dioxide will be excited and transition to the conduction band, leaving relatively stable holes in the valence band. Defects and dangling bonds in the nano-materials will capture electrons or holes and cause them to diffuse to the surface of the particles respectively, generating a strong redox potential, and degrading organic substances into gases and water without consuming nano-titanium dioxide, thereby removing surface organic pollutants. Moreover, the modified nano-titanium dioxide particle solution can crosslink with the modified organosilicon oligomer and polyurethane, improving the compatibility between the nano-particles and the resin. At the same time, the particles are wrapped by a large amount of oligomers, resulting in an increase in roughness, and thus effectively improving the hydrophobicity of the coating.

[0010] Preferably, the oligomeric diol is polytetramethylene ether glycol with a molecular weight of 650.

[0011] Preferably, the aromatic diisocyanate is one of diphenylmethane diisocyanate and toluene diisocyanate.

[0012] The organic solvent is propylene glycol; the catalyst is dibutyltin dilaurate; the solid-liquid ratio of the oligomeric diol to the organic solvent is 1:(10 - 13) g / mL; the mass ratio of the oligomeric diol to the catalyst is 1:(0.014 - 0.09).

[0013] Preferably, the raw materials of the modified organosilicon oligomer include basic organosilicon oligomer, absolute ethanol, and perfluorodecyltrimethoxysilane with a mass fraction of 1%, and the mass ratio is 1:(0.4 - 0.6):(0.08 - 0.1).

[0014] By adopting the above technical solution, perfluorodecyltrimethoxysilane is used to modify the basic organosilicon oligomer. Perfluorodecyltrimethoxysilane has a very high surface tension, so it can improve the anti-adhesion of the coating surface, prevent pollutants from adhering, and make the surface easier to clean; at the same time, it can also enhance the weather resistance and chemical resistance of the coating surface, making the coating more durable.

[0015] Preferably, the basic organosilicon oligomer is composed of the following raw materials in parts by weight: 30 - 36 parts of absolute ethanol, 3 - 5 parts of deionized water, 1 - 3 parts of ammonia water, 0.4 - 0.6 parts of silane coupling agent KH-560, and 3.5 - 5.5 parts of tetraethyl orthosilicate.

[0016] Preferably, the raw materials of the modified nano-titanium dioxide particle solution include nano-titanium dioxide particle solution, absolute ethanol, and perfluorodecyltrimethoxysilane with a mass fraction of 1%, and the mass ratio is 1:(0.5 - 0.7):(0.08 - 0.1).

[0017] By adopting the above technical solution, perfluorodecyltrimethoxysilane is used to modify the nano-titanium dioxide particle solution, and an organosilicon modified layer can be formed on the surface of the nano-titanium dioxide, improving its surface hydrophobicity, thereby improving the dispersion of the nano-titanium dioxide in the solution, making it more evenly dispersed in the coating, improving the self-cleaning effect of the coating. At the same time, the modified nano-titanium dioxide particles can crosslink with the modified organosilicon oligomer and polyurethane, improving the compatibility between the nano-particles and the resin, and further improving the durability of the coating.

[0018] Preferably, the nano-titanium dioxide particle solution is composed of the following raw materials in parts by weight: 30 - 40 parts of absolute ethanol, 3 - 5 parts of deionized water, 0.9 - 1.3 parts of ammonia water, and 2 - 2.5 parts of tetrabutyl titanate.

[0019] This application also provides a preparation method of a self-cleaning polyurethane thermal insulation coating material for building surfaces, including the following steps:

[0020] After adding the oligomeric diol into the reactor, heat it to 110 - 120 °C and evacuate until there are no bubbles in the reactor. Then cool it to 70 - 80 °C, add an organic solvent and a catalyst into the reactor, and stir and reflux for 8 - 18 min; add the aromatic diisocyanate and react for 2 - 4 h; add the modified silicone oligomer and react for 1 - 2 h, then add the modified nano-titanium dioxide particle solution, continue to stir for 15 - 25 min, and cool to room temperature to obtain the self-cleaning polyurethane thermal insulation coating material for building surfaces.

[0021] Preferably, the preparation method of the modified silicone oligomer includes the following steps:

[0022] S1. Take 30 - 36 parts of absolute ethanol, add 3 - 5 parts of deionized water and mix evenly, then add 1 - 3 parts of ammonia water and 0.4 - 0.6 part of silane coupling agent KH-560 respectively, and stir for 5 - 10 min to obtain a mixture; drop 3.5 - 5.5 parts of tetraethyl orthosilicate into the mixture drop by drop under stirring, and continue to stir for 1 - 2 h to obtain the basic silicone oligomer;

[0023] S2. Dilute the basic silicone oligomer obtained in S1 with absolute ethanol at a mass ratio of 1:(0.4 - 0.6), then drop 1% perfluorodecyltrimethoxysilane, and the weight ratio of 1% perfluorodecyltrimethoxysilane to the basic oligomer is (0.08 - 0.1):1, and stir at room temperature for 10 - 20 min to obtain the modified silicone oligomer.

[0024] Preferably, the preparation method of the modified nano-titanium dioxide particle solution includes the following steps:

[0025] S1. Measure 30 - 40 parts of absolute ethanol, add 3 - 5 parts of deionized water and 0.9 - 1.3 parts of ammonia water in sequence, and stir evenly to obtain a mixture; drop 2 - 2.5 parts of tetrabutyl titanate into the mixture drop by drop under stirring, and stir at 60 - 70 °C for 6 - 8 h to obtain the nano-titanium dioxide particle solution;

[0026] S2. Dilute the nano-titanium dioxide particle solution with absolute ethanol at a mass ratio of 1:(0.5 - 0.7), then drop 1% perfluorodecyltrimethoxysilane, and the weight ratio of 1% perfluorodecyltrimethoxysilane to the basic oligomer is (0.08 - 0.1):1, and stir at room temperature for 10 - 20 min to obtain the modified nano-titanium dioxide particle solution.

[0027] In summary, the present application includes at least one of the following beneficial technical effects:

[0028] 1. By adopting the above technical solution, a modified organosilicon oligomer is added in the preparation of the polyurethane coating. On the one hand, it can improve the high-temperature resistance, weather resistance and other properties of the polyurethane coating, and enhance the durability of the coating. On the other hand, the modified organosilicon oligomer can increase the surface energy of the composite coating, thereby improving the hydrophobicity of the polyurethane coating;

[0029] 2. Then, by compounding a modified nano-titanium dioxide particle solution, under the action of light, the electrons in the valence band of the photocatalytic material nano-titanium dioxide will be excited and transition to the conduction band, leaving relatively stable holes in the valence band. Defects and dangling bonds in the nano-material will capture electrons or holes and cause them to diffuse to the surface of the particles respectively, generating a strong oxidation-reduction potential, and degrading organic substances into gases and water without consuming nano-titanium dioxide, thereby removing surface organic pollutants; and the modified nano-titanium dioxide particle solution can crosslink with the modified organosilicon oligomer and polyurethane, improving the compatibility between the nano-particles and the resin. At the same time, the particles are wrapped by a large amount of oligomers, resulting in an increase in roughness, thereby effectively improving the hydrophobicity of the coating. Specific embodiments

[0030] The following further elaborates on this application with reference to embodiments.

[0031] Preparation examples

[0032] Preparation example 1 Preparation of modified organosilicon oligomer

[0033] Preparation example 1.1

[0034] S1. Take 30 g of absolute ethanol, add 3 g of deionized water and mix evenly, then add 1 g of ammonia water and 0.4 g of silane coupling agent KH-560 respectively, and stir at room temperature with a stirring speed of 400 rpm for 5 min to obtain a mixture; drop 3.5 g of tetraethyl orthosilicate into the mixture drop by drop under stirring, and continue to stir at room temperature with a stirring speed of 400 rpm for 1 h to obtain a basic organosilicon oligomer;

[0035] S2. Mix and dilute 10 g of the basic organosilicon oligomer obtained in S1 with 4 g of absolute ethanol, then drop 0.8 g of 1% perfluorodecyltrimethoxysilane, and stir at room temperature with a stirring speed of 600 rpm for 10 min to obtain a modified organosilicon oligomer.

[0036] Preparation example 1.2

[0037] S1. Take 33 g of absolute ethanol, add 4 g of deionized water and mix evenly. Then add 2 g of ammonia water and 0.5 g of silane coupling agent KH-560, and stir at room temperature for 8 min at a stirring speed of 450 rpm to obtain a mixture. Dropwise add 4.5 g of tetraethyl orthosilicate into the mixture under stirring, and continue to stir at room temperature for 1.5 h at a stirring speed of 450 rpm to obtain an alkaline organosilicon oligomer;

[0038] S2. Mix and dilute 10 g of the alkaline organosilicon oligomer obtained in S1 with 4 g of absolute ethanol, then dropwise add 0.8 g of 1% perfluorodecyltrimethoxysilane, and stir at room temperature for 15 min at a stirring speed of 650 rpm to obtain a modified organosilicon oligomer.

[0039] Preparation Example 1.3

[0040] S1. Take 36 g of absolute ethanol, add 5 g of deionized water and mix evenly. Then add 3 g of ammonia water and 0.6 g of silane coupling agent KH-560, and stir at room temperature for 10 min at a stirring speed of 500 rpm to obtain a mixture. Dropwise add 5.5 g of tetraethyl orthosilicate into the mixture under stirring, and continue to stir at room temperature for 2 h at a stirring speed of 500 rpm to obtain an alkaline organosilicon oligomer;

[0041] S2. Mix and dilute 10 g of the alkaline organosilicon oligomer obtained in S1 with 4 g of absolute ethanol, then dropwise add 0.8 g of 1% perfluorodecyltrimethoxysilane, and stir at room temperature for 20 min at a stirring speed of 700 rpm to obtain a modified organosilicon oligomer.

[0042] Preparation Example 1.4

[0043] The difference between Preparation Example 1.4 and Preparation Example 1.1 is that in Preparation Example 1.4, the mass of the alkaline organosilicon oligomer used in step S2 is 10 g, the mass of absolute ethanol is 5 g, and the mass of 1% perfluorodecyltrimethoxysilane is 0.9 g.

[0044] Preparation Example 1.5

[0045] The difference between Preparation Example 1.5 and Preparation Example 1.1 is that in Preparation Example 1.5, the mass of the alkaline organosilicon oligomer used in step S2 is 10 g, the mass of absolute ethanol is 6 g, and the mass of 1% perfluorodecyltrimethoxysilane is 1 g.

[0046] Preparation Example 1.6

[0047] Preparation Example 1.6 is different from Preparation Example 1.1 in that in step S2, the mass of the basic organosilicon oligomer used is 10 g, the mass of absolute ethanol is 2 g, and the mass of perfluorodecyltrimethoxysilane with a mass fraction of 1% is 0.6 g.

[0048] Preparation Example 1.7

[0049] Preparation Example 1.7 is different from Preparation Example 1.1 in that in step S2, the mass of the basic organosilicon oligomer used is 10 g, the mass of absolute ethanol is 8 g, and the mass of perfluorodecyltrimethoxysilane with a mass fraction of 1% is 1.2 g.

[0050] Preparation Example 2 Preparation of Modified Nano Titanium Dioxide Particle Solution

[0051] Preparation Example 2.1

[0052] S1. Measure 30 g of absolute ethanol, and successively add 3 g of deionized water and 0.9 g of ammonia water. Stir at 60 °C and a stirring speed of 400 rpm for 10 min to obtain a mixture; dropwise add 2 g of tetrabutyl titanate to the mixture under stirring, and stir at 60 °C for 6 h to obtain a nano titanium dioxide particle solution;

[0053] S2. Mix and dilute 10 g of the nano titanium dioxide particle solution obtained in S1 with 5 g of absolute ethanol, then dropwise add 0.8 g of perfluorodecyltrimethoxysilane with a mass fraction of 1%, and stir at room temperature and a stirring speed of 600 rpm for 10 min to obtain a modified nano titanium dioxide particle solution.

[0054] Preparation Example 2.2

[0055] S1. Measure 35 g of absolute ethanol, and successively add 4 g of deionized water and 1.1 g of ammonia water. Stir at 65 °C and a stirring speed of 450 rpm for 15 min to obtain a mixture; dropwise add 2.3 g of tetrabutyl titanate to the mixture under stirring, and stir at 65 °C for 7 h to obtain a nano titanium dioxide particle solution;

[0056] S2. Mix and dilute 10 g of the nano titanium dioxide particle solution obtained in S1 with 5 g of absolute ethanol, then dropwise add 0.8 g of perfluorodecyltrimethoxysilane with a mass fraction of 1%, and stir at room temperature and a stirring speed of 650 rpm for 15 min to obtain a modified nano titanium dioxide particle solution.

[0057] Preparation Example 2.3

[0058] S1. Measure 40 g of absolute ethanol, sequentially add 5 g of deionized water and 1.3 g of ammonia water, and stir at 70 °C and a stirring speed of 500 rpm for 20 min to obtain a mixture; gradually add 2.5 g of tetrabutyl titanate dropwise to the mixture under stirring, and stir at 70 °C for 8 h to obtain a nano-titanium dioxide particle solution;

[0059] S2. Mix and dilute 10 g of the nano-titanium dioxide particle solution obtained in S1 with 5 g of absolute ethanol, then add 0.8 g of 1% perfluorodecyltrimethoxysilane dropwise, and stir at room temperature and a stirring speed of 700 rpm for 20 min to obtain a modified nano-titanium dioxide particle solution.

[0060] Preparation Example 2.4

[0061] The difference between Preparation Example 2.4 and Preparation Example 2.1 is that in step S2 of Preparation Example 2.4, the mass of the nano-titanium dioxide particle solution used is 10 g, the mass of absolute ethanol is 6 g, and the mass of 1% perfluorodecyltrimethoxysilane is 0.9 g.

[0062] Preparation Example 2.5

[0063] The difference between Preparation Example 2.5 and Preparation Example 2.1 is that in step S2 of Preparation Example 2.5, the mass of the nano-titanium dioxide particle solution used is 10 g, the mass of absolute ethanol is 7 g, and the mass of 1% perfluorodecyltrimethoxysilane is 1 g.

[0064] Preparation Example 2.6

[0065] The difference between Preparation Example 2.6 and Preparation Example 2.1 is that in step S2 of Preparation Example 2.6, the mass of the nano-titanium dioxide particle solution used is 10 g, the mass of absolute ethanol is 4 g, and the mass of 1% perfluorodecyltrimethoxysilane is 0.6 g.

[0066] Preparation Example 2.7

[0067] The difference between Preparation Example 2.7 and Preparation Example 2.1 is that in step S2 of Preparation Example 2.7, the mass of the nano-titanium dioxide particle solution used is 10 g, the mass of absolute ethanol is 9 g, and the mass of 1% perfluorodecyltrimethoxysilane is 1.2 g.

[0068] Example

[0069] Example 1

[0070] After adding 10 g of polytetramethylene ether glycol (molecular weight 650) into the reactor, heat it to 110 °C and evacuate until there are no bubbles in the reactor. Then cool it down to 70 °C, add 100 mL of organic solvent propylene glycol and 0.22 g of catalyst dibutyltin dilaurate into the reactor, and stir and reflux for 8 min; add 11.55 g of diphenylmethane diisocyanate and react for 2 h; add 10 g of the modified silicone oligomer prepared in Preparation Example 1.1 and react for 1 h, then add 10 g of the modified nano-titanium dioxide particle solution prepared in Preparation Example 2.1, continue to stir for 15 min, and cool to room temperature to obtain a self-cleaning polyurethane thermal insulation coating material for building surfaces.

[0071] Example 2

[0072] After adding 10 g of polytetramethylene ether glycol into the reactor, heat it to 115 °C and evacuate until there are no bubbles in the reactor. Then cool it down to 75 °C, add 110 mL of organic solvent propylene glycol and 0.5 g of catalyst dibutyltin dilaurate into the reactor, and stir and reflux for 13 min; add 15.4 g of diphenylmethane diisocyanate and react for 3 h; add 10 g of the modified silicone oligomer prepared in Preparation Example 1.1 and react for 1.5 h, then add 10 g of the modified nano-titanium dioxide particle solution prepared in Preparation Example 2.1, continue to stir for 20 min, and cool to room temperature to obtain a self-cleaning polyurethane thermal insulation coating material for building surfaces.

[0073] Example 3

[0074] After adding 10 g of polytetramethylene ether glycol into the reactor, heat it to 120 °C and evacuate until there are no bubbles in the reactor. Then cool it down to 80 °C, add 130 mL of organic solvent propylene glycol and 0.9 g of catalyst dibutyltin dilaurate into the reactor, and stir and reflux for 18 min; add 19.25 g of diphenylmethane diisocyanate and react for 4 h; add 10 g of the modified silicone oligomer prepared in Preparation Example 1.1 and react for 2 h, then add 10 g of the modified nano-titanium dioxide particle solution prepared in Preparation Example 2.1, continue to stir for 25 min, and cool to room temperature to obtain a self-cleaning polyurethane thermal insulation coating material for building surfaces.

[0075] Example 4

[0076] After adding 10 g of polypropylene glycol (with a molecular weight of 2000) into the reactor, it was heated to 110 °C and evacuated until no bubbles remained in the reactor. Then it was cooled to 70 °C, 100 mL of the organic solvent propylene glycol and 0.14 g of the catalyst dibutyltin dilaurate were added into the reactor, and it was stirred and refluxed for 8 min; 3.75 g of diphenylmethane diisocyanate was added and reacted for 2 h; 10 g of the modified silicone oligomer prepared in Preparation Example 1.1 was added and reacted for 1 h, then 10 g of the modified nano-titanium dioxide particle solution prepared in Preparation Example 2.1 was added, and it was continuously stirred for 15 min. After cooling to room temperature, a self-cleaning polyurethane thermal insulation coating material for building surfaces was obtained.

[0077] Example 5

[0078] After adding 10 g of polytetramethylene ether glycol (with a molecular weight of 650) into the reactor, it was heated to 110 °C and evacuated until no bubbles remained in the reactor. Then it was cooled to 70 °C, 100 mL of the organic solvent propylene glycol and 0.18 g of the catalyst dibutyltin dilaurate were added into the reactor, and it was stirred and refluxed for 8 min; 8 g of toluene diisocyanate was added and reacted for 2 h; 10 g of the modified silicone oligomer prepared in Preparation Example 1.1 was added and reacted for 1 h, then 10 g of the modified nano-titanium dioxide particle solution prepared in Preparation Example 2.1 was added, and it was continuously stirred for 15 min. After cooling to room temperature, a self-cleaning polyurethane thermal insulation coating material for building surfaces was obtained.

[0079] Example 6

[0080] The difference between Example 6 and Example 1 is that in Example 6, the modified silicone oligomer used was from Preparation Example 1.1 with a mass of 20 g; the modified nano-titanium dioxide particle solution was from Preparation Example 2.1 with a mass of 12.5 g.

[0081] Example 7

[0082] The difference between Example 7 and Example 1 is that in Example 7, the modified silicone oligomer used was from Preparation Example 1.1 with a mass of 30 g; the modified nano-titanium dioxide particle solution was from Preparation Example 2.1 with a mass of 15 g.

[0083] Example 8

[0084] The difference between Example 8 and Example 1 is that in Example 8, the modified silicone oligomer used was from Preparation Example 1.2 with a mass of 10 g.

[0085] Example 9

[0086] The difference between Example 9 and Example 1 is that in Example 9, the modified silicone oligomer used was from Preparation Example 1.3 with a mass of 10 g.

[0087] Example 10

[0088] Example 10 is different from Example 1 in that the modified organosilicon oligomer used in Example 10 is from Preparation Example 1.4 and has a mass of 10 g.

[0089] Example 11

[0090] Example 11 is different from Example 1 in that the modified organosilicon oligomer used in Example 11 is from Preparation Example 1.5 and has a mass of 10 g.

[0091] Example 12

[0092] Example 12 is different from Example 1 in that the modified organosilicon oligomer used in Example 12 is from Preparation Example 1.6 and has a mass of 10 g.

[0093] Example 13

[0094] Example 13 is different from Example 1 in that the modified organosilicon oligomer used in Example 13 is from Preparation Example 1.7 and has a mass of 10 g.

[0095] Example 14

[0096] Example 14 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 14 is from Preparation Example 2.2 and has a mass of 10 g.

[0097] Example 15

[0098] Example 15 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 15 is from Preparation Example 2.3 and has a mass of 10 g.

[0099] Example 16

[0100] Example 16 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 16 is from Preparation Example 2.4 and has a mass of 10 g.

[0101] Example 17

[0102] Example 17 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 17 is from Preparation Example 2.5 and has a mass of 10 g.

[0103] Example 18

[0104] Example 18 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 18 is from Preparation Example 2.6 and has a mass of 10 g.

[0105] Example 19

[0106] Example 19 is different from Example 1 in that the modified nano-titanium dioxide particle solution used in Example 19 is from Preparation Example 2.7 and has a mass of 10 g.

[0107] Comparative Example

[0108] Comparative Example 1

[0109] Comparative Example 1 is different from Example 1 in that the modified silicone oligomer used in Comparative Example 1 is from Preparation Example 1.1 and has a mass of 5 g; the modified nano-titanium dioxide particle solution is from Preparation Example 2.1 and has a mass of 5 g.

[0110] Comparative Example 2

[0111] Comparative Example 2 is different from Example 1 in that the modified silicone oligomer used in Comparative Example 2 is from Preparation Example 1.1 and has a mass of 40 g; the modified nano-titanium dioxide particle solution is from Preparation Example 2.1 and has a mass of 20 g.

[0112] Performance Detection Test

[0113] I. Using GB / T 30693-2014 "Measurement of the Contact Angle of Plastic Films with Water", the water contact angles of the self-cleaning polyurethane thermal insulation coating materials applied to the building surface obtained in Examples 1-19 and Comparative Examples 1-2 were detected, and the results are shown in Table 1.

[0114] Table 1 Water Contact Angle Detection Results

[0115]

[0116] It can be seen from the detection results in Table 1 that the water contact angle of the self-cleaning polyurethane thermal insulation coating material applied to the building surface provided by this application can reach more than 150°, indicating that the self-cleaning polyurethane thermal insulation coating material provided by this application has superhydrophobicity and has self-cleaning ability similar to the lotus leaf surface.

[0117] It can be seen from the detection results of Comparative Examples 1-2 that when the mass ratio of the oligomeric diol to the modified silicone oligomer and the modified nano-titanium dioxide particle solution used in the preparation of the self-cleaning polyurethane thermal insulation coating material applied to the building surface of this application is lower than or exceeds the range of 1:1 - 3:1 - 1.5, the water contact angle of the obtained polyurethane thermal insulation coating material is lower than 150°, that is, the obtained coating does not have superhydrophobicity.

[0118] This specific embodiment is only an explanation of this application and is not a limitation of this application. Those skilled in the art can make modifications to this embodiment without creative contributions according to needs after reading this specification, but as long as it is within the scope of the claims of this application, it is protected by the patent law.

Claims

1. A self-cleaning polyurethane thermal insulation coating material for building surfaces, characterized in that: It includes the following raw materials: Oligomeric diol, aromatic diisocyanate, organic solvent, catalyst, modified organosilicon oligomer, modified nano-titanium dioxide particle solution; the molar ratio of the oligomeric diol to the aromatic diisocyanate is 1:(3 - 5), and the mass ratio of the oligomeric diol to the modified organosilicon oligomer and the modified nano-titanium dioxide particle solution is 1:(1 - 3):(1 - 1.5); The oligomeric diol is polytetramethylene ether glycol with a molecular weight of 650; The organic solvent is propylene glycol; The modified organosilicon oligomer is composed of the following raw materials: basic organosilicon oligomer, absolute ethanol, perfluorodecyltrimethoxysilane with a mass fraction of 1%, and the mass ratio is 1:(0.4 - 0.6):(0.08 - 0.1); The basic organosilicon oligomer is composed of the following raw materials by weight: 30 - 36 parts of absolute ethanol, 3 - 5 parts of deionized water, 1 - 3 parts of ammonia water, 0.4 - 0.6 parts of silane coupling agent KH-560, 3.5 - 5.5 parts of tetraethyl orthosilicate; The modified nano-titanium dioxide particle solution is composed of the following raw materials: nano-titanium dioxide particle solution, absolute ethanol, perfluorodecyltrimethoxysilane with a mass fraction of 1%, and the mass ratio is 1:(0.5 - 0.7):(0.08 - 0.1); The nano-titanium dioxide particle solution is composed of the following raw materials by weight: 30 - 40 parts of absolute ethanol, 3 - 5 parts of deionized water, 0.9 - 1.3 parts of ammonia water, 2 - 2.5 parts of tetrabutyl titanate; 2. The self-cleaning polyurethane thermal insulation coating material for building surfaces according to claim 1, characterized in that: The aromatic diisocyanate is one of diphenylmethane diisocyanate and toluene diisocyanate; 3. The self-cleaning polyurethane thermal insulation coating material for building surfaces according to claim 1, characterized in that: The catalyst is dibutyltin dilaurate; the solid-liquid ratio of the oligomeric diol to the organic solvent is 1:(10 - 13) g / mL; the mass ratio of the oligomeric diol to the catalyst is 1:(0.014 - 0.09).

4. The preparation method of the self-cleaning polyurethane thermal insulation coating material for building surface according to any one of claims 1-3, characterized in that: It includes the following steps: Add the oligomeric diol into the reactor, heat it to 110 - 120 °C and evacuate until there are no bubbles in the reactor, cool it down to 70 - 80 °C, add the organic solvent and the catalyst into the reactor, stir and reflux for 8 - 18 min; add the aromatic diisocyanate and react for 2 - 4 h; add the modified organosilicon oligomer and react for 1 - 2 h, then add the modified nano-titanium dioxide particle solution, continue to stir for 15 - 25 min, and cool to room temperature to obtain a self-cleaning polyurethane thermal insulation coating material for building surfaces.

5. The preparation method of the self-cleaning polyurethane thermal insulation coating material for building surface according to claim 4, characterized in that: The preparation method of the modified organosilicon oligomer includes the following steps: S1. Take 30 - 36 parts of absolute ethanol, add 3 - 5 parts of deionized water and mix evenly, then add 1 - 3 parts of ammonia water and 0.4 - 0.6 parts of silane coupling agent KH-560 respectively, stir for 5 - 10 min to obtain a mixture; drop 3.5 - 5.5 parts of tetraethyl orthosilicate into the mixture drop by drop under stirring, and continue to stir for 1 - 2 h to obtain the basic organosilicon oligomer; S2. Dilute the basic organosilicon oligomer obtained in S1 with absolute ethanol at a mass ratio of 1:(0.4 - 0.6), then dropwise add perfluorodecyltrimethoxysilane with a mass fraction of 1%. The weight ratio of perfluorodecyltrimethoxysilane with a mass fraction of 1% to the basic oligomer is (0.08 - 0.1):

1. Stir at room temperature for 10 - 20 min to obtain a modified organosilicon oligomer.

6. The preparation method of the self-cleaning polyurethane thermal insulation coating material for building surface according to claim 4, characterized in that: The preparation method of the modified nano-titanium dioxide particle solution comprises the following steps: S1. Measure 30 - 40 parts of absolute ethanol, sequentially add 3 - 5 parts of deionized water and 0.9 - 1.3 parts of ammonia water, and stir evenly to obtain a mixture; dropwise add 2 - 2.5 parts of tetrabutyl titanate to the mixture under stirring, and stir at 60 - 70 °C for 6 - 8 h to obtain a nano-titanium dioxide particle solution; S2. Dilute the nano-titanium dioxide particle solution with absolute ethanol at a mass ratio of 1:(0.5 - 0.7), then dropwise add perfluorodecyltrimethoxysilane with a mass fraction of 1%. The weight ratio of perfluorodecyltrimethoxysilane with a mass fraction of 1% to the basic oligomer is (0.08 - 0.1):

1. Stir at room temperature for 10 - 20 min to obtain a modified nano-titanium dioxide particle solution.

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