Self-cleaning hydrophobic building membrane material with micro-nano coarse structure

Abstract

The invention relates to a self-cleaning hydrophobic building membrane material with a micro-nano coarse structure, and belongs to the technical field of building membrane materials. According to the invention, vinyl-terminated polydimethylsiloxane is modified, the molecular structure of vinyl-terminated polydimethylsiloxane is highly branched in a manner of first cracking and then hydrolytic condensation, and entanglement and interaction among molecular chains are increased by constructing a complex molecular topological structure, so that the defects that unmodified linear long-chain silicone oil is easy to slip and low in strength are overcome; a phosphate flame-retardant structure is further introduced into a flame-retardant functional polysiloxane chain segment of a final modified finished product, so that the flame-retardant functional polysiloxane can be endowed with good intrinsic flame retardance, and the problems of non-uniform dispersion and mechanical property reduction caused by compatibility defects of an additional flame retardant, polyurethane and silicone oil are solved.

Description

Technical Field

[0001] This invention belongs to the field of architectural membrane technology, specifically, it relates to a self-cleaning hydrophobic architectural membrane with a micro-nano rough structure. Background Technology

[0002] Enhancing the hydrophobicity of materials can improve their water contact angle and reduce their surface energy, enabling them to possess hydrophobic self-cleaning properties. This is significant for maintaining the building's appearance and reducing maintenance. Currently, the mainstream technical approach for constructing superhydrophobic architectural membranes involves introducing low-surface-energy silicone oil and nano-silica into a polymer matrix to jointly construct a micro-nano rough structure. However, the significant difference in hydrophilicity between silicone oil and the polymer matrix leads to extremely poor compatibility. If silicone oil is added to the polymer matrix through blending, it will cause severe phase separation problems, resulting in poor film formation, uneven hydrophobicity, and a significant decrease in mechanical properties. If silicone oil is introduced into the polymer matrix through a chemical reaction, linear silicone oil has poor mechanical strength and is prone to slippage, ultimately becoming a weak point in the load-bearing structure and severely reducing the material's mechanical strength. To address these technical shortcomings, this invention provides a self-cleaning hydrophobic architectural membrane with a micro-nano rough structure. Summary of the Invention

[0003] The purpose of this invention is to provide a self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure to solve the problems mentioned in the background art.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 20-30 parts of polyurethane polyol, 20-40 parts of flame-retardant functionalized polysiloxane segments, 12-18 parts of polyisocyanate, 5-12 parts of nano-silica, 0.5-2 parts of silane coupling agent, 1-2 parts of photoinitiator, 0.05-0.25 parts of catalyst, and 40-60 parts of organic solvent;

[0006] Furthermore, the polyurethane polyol is polycaprolactone diol with a molecular weight of 2000-3000.

[0007] Furthermore, the polyisocyanate is at least one of isophorone diisocyanate and diphenylmethane diisocyanate.

[0008] Furthermore, the silane coupling agent is at least one of KH-580 and KH-590.

[0009] Furthermore, the photoinitiator is 1-hydroxycyclohexylphenyl ketone or benzoin dimethyl ether.

[0010] Furthermore, the catalyst is at least one of dibutyltin dilaurate and stannous octoate.

[0011] Furthermore, the organic solvent is tetrahydrofuran.

[0012] Furthermore, the flame-retardant functionalized polysiloxane segments can be prepared by the following steps:

[0013] S1. Hydroxyvinyl polydimethylsiloxane is obtained by catalytic cracking of terminal vinyl polydimethylsiloxane under acidic conditions;

[0014] The reaction process is as follows: terminal vinyl polydimethylsiloxane, p-toluenesulfonic acid, tetrahydrofuran, and anhydrous ethanol are mixed in a reaction vessel, stirred and reacted at 50-60℃ for 4-6 hours. After the reaction is completed, the reaction solution is poured into cold deionized water, and then the oily substance is separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0015] S2. Triethylene glycol phosphite is reacted with chloromethyltriethoxysilane via the Eberzoff reaction to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0016] The reaction process is as follows: Triethylene glycol phosphite, chloromethyltriethoxysilane, and toluene are mixed in a reaction vessel, stirred, and reacted at 60-80℃ for 4-8 hours. After the reaction is completed, toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0017] S3. Use a flame-retardant functionalized siloxane crosslinking agent to extend the chain of hydroxyvinyl polydimethylsiloxane through hydrolysis and condensation reaction, and use hexamethyldisiloxane to end-cap to obtain flame-retardant functionalized polysiloxane segments.

[0018] The reaction process is as follows: Flame-retardant functionalized siloxane crosslinking agent, hydroxyvinyl polydimethylsiloxane, anhydrous ethanol, and deionized water are mixed in a reaction vessel. After stirring, dilute hydrochloric acid is added dropwise to adjust the pH of the system to 4-6, and the reaction is carried out at 40-60℃ for 2-4 hours. Then, hexamethyldisiloxane is added to the system, and the reaction is continued at 50-80℃ for 2-6 hours. After the reaction is completed, the system is extracted with dichloromethane, and the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0019] Furthermore, the self-cleaning hydrophobic architectural membrane material can be prepared by the following steps:

[0020] The first step is to graft a silane coupling agent onto the surface of nano-silica to obtain modified nano-silica;

[0021] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. The composite slurry is then poured into a mold and undergoes pre-curing, photo-curing, and final curing to obtain a self-cleaning hydrophobic architectural membrane.

[0022] Furthermore, the method for grafting a silane coupling agent onto the surface of nano-silica is as follows:

[0023] Under nitrogen protection, silane coupling agent, nano-silica, and 40-80% (v / v) aqueous ethanol solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 40-60°C for 2-3 hours. After the reaction was completed, the nano-silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano-silica.

[0024] Furthermore, the pre-curing conditions are as follows: heating reaction at a temperature of 40–50°C for 40–60 minutes.

[0025] Furthermore, the photocuring conditions are as follows: the intensity is 10–50 mW / cm². 2 Irradiate under ultraviolet light for 5–15 minutes.

[0026] Furthermore, the final curing conditions are as follows: heating reaction at a temperature of 80–100°C for 120–180 min.

[0027] The beneficial effects of this invention are:

[0028] 1) This invention modifies vinyl-terminated polydimethylsiloxane by first pyrolyzing and then hydrolyzing and condensing it to make its molecular structure highly branched. By constructing a complex molecular topology, the entanglement and interaction between molecular chains are increased to compensate for the shortcomings of unmodified linear long-chain silicone oil, such as easy slippage and low strength. Moreover, the flame-retardant functionalized polysiloxane segments of the final modified product also introduce phosphate ester flame-retardant structures, which can endow it with good intrinsic flame retardancy and solve the problems of uneven dispersion and decreased mechanical properties caused by the incompatibility defects of added flame retardants with polyurethane and silicone oil.

[0029] 2) The flame-retardant functionalized polysiloxane segments of this invention contain both hydroxyl and vinyl groups. The hydroxyl groups can react with polyisocyanates to form a polyurethane chemical crosslinking network, while the vinyl groups can undergo a click chemical reaction with the thiol groups on the surface of the silane coupling agent under ultraviolet light irradiation to form a stable chemical bond between the polyurethane network and nano-silica. The interpenetrating entanglement of nanoparticles and the polyurethane network forms an extremely strong composite network that effectively resists external impacts and scratches, ensuring the long-term stability of the micro-nano rough structure and superhydrophobic function, thus solving the fundamental problem of easy wear and failure of traditional physically attached hydrophobic films.

[0030] 3) In the photocuring step, the modified nano-silica is uniformly and firmly bonded to the polymer matrix through click reaction, which ensures the dispersion and stability of nano-silica in the membrane material and ensures that a uniform and stable micro-nano rough structure can be formed on the surface of the building membrane material, so that the surface of the building membrane material can exhibit good hydrophobic and self-cleaning effects. Detailed Implementation

[0031] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0032] It should be understood that the expression “one or more of…” individually includes each of the objects described after the expression, as well as various different combinations of two or more of the described objects, unless otherwise understood from the context and usage. The expression “and / or” combined with three or more described objects should be understood to have the same meaning, unless otherwise understood from the context.

[0033] It should be understood that the use of “including,” “having,” or “containing,” including its grammatical synonyms, should generally be understood as open-ended and non-restrictive, for example, not excluding other unstated elements or steps, unless otherwise specifically stated or understood from the context.

[0034] It should be understood that the order of the steps or the order in which certain actions are performed is not important as long as the invention remains operational. Furthermore, two or more steps or actions can be performed simultaneously.

[0035] Furthermore, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as precisely as possible. However, any value inevitably contains standard deviations due to individual test methods. Therefore, unless explicitly stated otherwise, it should be understood that all ranges, quantities, values, and percentages used in this disclosure are modified with the word "approximately". Here, "approximately" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a specific value or range.

[0036] Example 1

[0037] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 20 parts polyurethane polyol, 20 parts flame-retardant functionalized polysiloxane segments, 12 parts polyisocyanate, 5 parts nano silica, 0.5 parts silane coupling agent, 1 part photoinitiator, 0.05 parts catalyst, and 40 parts organic solvent.

[0038] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 2000, the polyisocyanate used is isophorone diisocyanate, the silane coupling agent used is KH-590, the photoinitiator used is 1-hydroxycyclohexylphenyl ketone, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0039] S1. By mass, 30 parts of vinyl-terminated polydimethylsiloxane with a molecular weight of 2000, 2 parts of p-toluenesulfonic acid, 90 parts of tetrahydrofuran, and 30 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 50°C for 6 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0040] S2. By mass, 8 parts of triethylene glycol phosphite, 8 parts of chloromethyltriethoxysilane, and 60 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 60°C for 8 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0041] S3. By mass fraction, 10 parts of flame-retardant functionalized siloxane crosslinking agent, 20 parts of hydroxyvinyl polydimethylsiloxane, 60 parts of anhydrous ethanol, and 5 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 4, and the reaction is carried out at 40°C for 4 hours. Then, 2 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 50°C for 6 hours. After the reaction is completed, the system is extracted with dichloromethane, and the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0042] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0043] Step 1: Under nitrogen protection, 0.5 parts of silane coupling agent, 5 parts of nano silica, and 50 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 40°C for 3 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0044] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 40°C for 60 minutes. The mold is then transferred to an ultraviolet curing chamber with a curing intensity of 10 mW / cm². 2 After being irradiated with ultraviolet light for 15 minutes and cured by light, the material is heated at 80℃ for 180 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0045] Example 2

[0046] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 20 parts polyurethane polyol, 20 parts flame-retardant functionalized polysiloxane segments, 12 parts polyisocyanate, 5 parts nano silica, 0.5 parts silane coupling agent, 1 part photoinitiator, 0.05 parts catalyst, and 40 parts organic solvent.

[0047] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 2000, the polyisocyanate used is diphenylmethane diisocyanate, the silane coupling agent used is KH-590, the photoinitiator used is 1-hydroxycyclohexylphenyl ketone, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0048] S1. By mass, 30 parts of vinyl-terminated polydimethylsiloxane with a molecular weight of 2000, 2 parts of p-toluenesulfonic acid, 90 parts of tetrahydrofuran, and 30 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 50°C for 6 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0049] S2. By mass, 8 parts of triethylene glycol phosphite, 8 parts of chloromethyltriethoxysilane, and 60 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 60°C for 8 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0050] S3. By mass fraction, 10 parts of flame-retardant functionalized siloxane crosslinking agent, 20 parts of hydroxyvinyl polydimethylsiloxane, 60 parts of anhydrous ethanol, and 5 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 4, and the reaction is carried out at 40°C for 4 hours. Then, 2 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 50°C for 6 hours. After the reaction is completed, the system is extracted with dichloromethane, and the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0051] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0052] Step 1: Under nitrogen protection, 0.5 parts of silane coupling agent, 5 parts of nano silica, and 50 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 40°C for 3 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0053] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 40°C for 60 minutes. The mold is then transferred to an ultraviolet curing chamber with a curing intensity of 10 mW / cm². 2 After being irradiated with ultraviolet light for 15 minutes and cured by light, the material is heated at 80℃ for 180 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0054] Example 3

[0055] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 25 parts polyurethane polyol, 30 parts flame-retardant functionalized polysiloxane segments, 15 parts polyisocyanate, 8.5 parts nano silica, 1.25 parts silane coupling agent, 1.5 parts photoinitiator, 0.15 parts catalyst, and 50 parts organic solvent.

[0056] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 2500, the polyisocyanate used is isophorone diisocyanate, the silane coupling agent used is KH-590, the photoinitiator used is benzoin dimethyl ether, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0057] S1. By mass, 45 parts of terminal vinyl polydimethylsiloxane with a molecular weight of 3000, 3 parts of p-toluenesulfonic acid, 120 parts of tetrahydrofuran, and 40 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 55°C for 5 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0058] S2. By mass, 12 parts of triethylene glycol phosphite, 12 parts of chloromethyltriethoxysilane, and 90 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 70°C for 6 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0059] S3. By mass fraction, 15 parts of flame-retardant functionalized siloxane crosslinking agent, 30 parts of hydroxyvinyl polydimethylsiloxane, 90 parts of anhydrous ethanol, and 8 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 5, and the reaction is carried out at 50°C for 3 hours. Then, 3 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 65°C for 4 hours. After the reaction is completed, the system is extracted with dichloromethane, and the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0060] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0061] Step 1: Under nitrogen protection, 1.25 parts of silane coupling agent, 8.5 parts of nano silica, and 85 parts of 60% ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 50°C for 2.5 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0062] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 45°C for 50 minutes. The mold is then transferred to an ultraviolet curing chamber and cured at an intensity of 30 mW / cm². 2 After being irradiated with ultraviolet light for 10 minutes and cured by light, the material is heated at 90℃ for 150 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0063] Example 4

[0064] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 25 parts polyurethane polyol, 30 parts flame-retardant functionalized polysiloxane segments, 15 parts polyisocyanate, 8.5 parts nano silica, 1.25 parts silane coupling agent, 1.5 parts photoinitiator, 0.15 parts catalyst, and 50 parts organic solvent.

[0065] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 2500, the polyisocyanate used is diphenylmethane diisocyanate, the silane coupling agent used is KH-590, the photoinitiator used is benzoin dimethyl ether, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0066] S1. By mass, 45 parts of terminal vinyl polydimethylsiloxane with a molecular weight of 3000, 3 parts of p-toluenesulfonic acid, 120 parts of tetrahydrofuran, and 40 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 55°C for 5 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0067] S2. By mass, 12 parts of triethylene glycol phosphite, 12 parts of chloromethyltriethoxysilane, and 90 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 70°C for 6 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0068] S3. By mass fraction, 15 parts of flame-retardant functionalized siloxane crosslinking agent, 30 parts of hydroxyvinyl polydimethylsiloxane, 90 parts of anhydrous ethanol, and 8 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 5, and the reaction is carried out at 50°C for 3 hours. Then, 3 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 65°C for 4 hours. After the reaction is completed, the system is extracted with dichloromethane, and the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0069] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0070] Step 1: Under nitrogen protection, 1.25 parts of silane coupling agent, 8.5 parts of nano silica, and 85 parts of 60% ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 50°C for 2.5 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0071] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 45°C for 50 minutes. The mold is then transferred to an ultraviolet curing chamber and cured at an intensity of 30 mW / cm². 2 After being irradiated with ultraviolet light for 10 minutes and cured by light, the material is heated at 90℃ for 150 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0072] Example 5

[0073] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 30 parts of polyurethane polyol, 40 parts of flame-retardant functionalized polysiloxane segments, 18 parts of polyisocyanate, 12 parts of nano silica, 2 parts of silane coupling agent, 2 parts of photoinitiator, 0.25 parts of catalyst, and 60 parts of organic solvent.

[0074] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 3000, the polyisocyanate used is isophorone diisocyanate, the silane coupling agent used is KH-580, the photoinitiator used is benzoin dimethyl ether, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0075] S1. By mass, 60 parts of terminal vinyl polydimethylsiloxane with a molecular weight of 4000, 4 parts of p-toluenesulfonic acid, 180 parts of tetrahydrofuran, and 60 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 4 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0076] S2. By mass, 16 parts of triethylene glycol phosphite, 16 parts of chloromethyltriethoxysilane, and 120 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 80°C for 4 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0077] S3. By mass fraction, 20 parts of flame-retardant functionalized siloxane crosslinking agent, 40 parts of hydroxyvinyl polydimethylsiloxane, 120 parts of anhydrous ethanol, and 10 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 6, and the reaction is carried out at 60°C for 2 hours. Then, 4 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 80°C for 2 hours. After the reaction is completed, the system is extracted with dichloromethane, and then the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0078] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0079] Step 1: Under nitrogen protection, 2 parts of silane coupling agent, 12 parts of nano silica, and 120 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 2 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0080] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 50°C for 40 minutes. The mold is then transferred to an ultraviolet curing chamber and cured at an intensity of 50 mW / cm². 2 After being irradiated with ultraviolet light for 5 minutes and cured by light, the material is heated at 100℃ for 120 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0081] Example 6

[0082] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 30 parts of polyurethane polyol, 40 parts of flame-retardant functionalized polysiloxane segments, 18 parts of polyisocyanate, 12 parts of nano silica, 2 parts of silane coupling agent, 2 parts of photoinitiator, 0.25 parts of catalyst, and 60 parts of organic solvent.

[0083] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 3000, the polyisocyanate used is diphenylmethane diisocyanate, the silane coupling agent used is KH-580, the photoinitiator used is benzoin dimethyl ether, the organic solvent used is tetrahydrofuran, and the flame-retardant functionalized polysiloxane segments used are prepared by the following steps:

[0084] S1. By mass, 60 parts of terminal vinyl polydimethylsiloxane with a molecular weight of 4000, 4 parts of p-toluenesulfonic acid, 180 parts of tetrahydrofuran, and 60 parts of anhydrous ethanol were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 4 hours. After the reaction was completed, the reaction solution was poured into cold deionized water. The oily substance was then separated and dried to obtain hydroxyl vinyl polydimethylsiloxane.

[0085] S2. By mass, 16 parts of triethylene glycol phosphite, 16 parts of chloromethyltriethoxysilane, and 120 parts of toluene are mixed in a reaction vessel. After stirring, the mixture is reacted at 80°C for 4 hours. After the reaction is completed, the toluene is removed by rotary evaporation to obtain a flame-retardant functionalized siloxane crosslinking agent.

[0086] S3. By mass fraction, 20 parts of flame-retardant functionalized siloxane crosslinking agent, 40 parts of hydroxyvinyl polydimethylsiloxane, 120 parts of anhydrous ethanol, and 10 parts of deionized water are mixed in a reaction vessel. After stirring, 10% by mass of dilute hydrochloric acid is added dropwise to adjust the pH of the system to 6, and the reaction is carried out at 60°C for 2 hours. Then, 4 parts of hexamethyldisiloxane are added to the system, and the reaction is continued at 80°C for 2 hours. After the reaction is completed, the system is extracted with dichloromethane, and then the organic phase is separated and the solvent is removed by rotary evaporation to obtain flame-retardant functionalized polysiloxane segments.

[0087] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0088] Step 1: Under nitrogen protection, 2 parts of silane coupling agent, 12 parts of nano silica, and 120 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 2 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0089] The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano-silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. This slurry is then poured into a mold and heated at 50°C for 40 minutes. The mold is then transferred to an ultraviolet curing chamber and cured at an intensity of 50 mW / cm². 2 After being irradiated with ultraviolet light for 5 minutes and cured by light, the material is heated at 100℃ for 120 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0090] Comparative Example 1

[0091] The difference between this comparative example and Example 6 is that flame-retardant functionalized polysiloxane segments are not prepared; instead, equal parts by mass of α,ω-dihydroxypolydimethylsiloxane are used to replace the flame-retardant functionalized polysiloxane segments in the raw materials, and no photoinitiator is added. The mass proportions of the remaining raw materials and the preparation method remain unchanged.

[0092] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 30 parts of polyurethane polyol, 40 parts of α,ω-dihydroxy polydimethylsiloxane, 18 parts of polyisocyanate, 12 parts of nano silica, 2 parts of silane coupling agent, 0.25 parts of catalyst, and 60 parts of organic solvent.

[0093] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 3000, the polyisocyanate used is diphenylmethane diisocyanate, the silane coupling agent used is KH-580, and the organic solvent used is tetrahydrofuran.

[0094] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0095] Step 1: Under nitrogen protection, 2 parts of silane coupling agent, 12 parts of nano silica, and 120 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 2 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0096] The second step involves uniformly mixing polyurethane polyol, α,ω-dihydroxy polydimethylsiloxane, polyisocyanate, modified nano silica, catalyst, and organic solvent to obtain a composite slurry. The composite slurry is then poured into a mold and heated at 50°C for 40 minutes. After that, it is heated at 100°C for another 120 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0097] Since the α,ω-dihydroxypolydimethylsiloxane structure in this comparative example does not contain double bonds, it cannot be photocured.

[0098] Comparative Example 2

[0099] The difference between this comparative example and Example 6 is that flame-retardant functionalized polysiloxane segments are not prepared. Instead, equal parts by mass of α,ω-dihydroxypolydimethylsiloxane are used to replace the flame-retardant functionalized polysiloxane segments in the raw materials. No photoinitiator is added, and 8 parts of flame retardant dimethyl phosphite are added. The mass proportions of the remaining raw materials and the preparation method remain unchanged.

[0100] A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure comprises the following raw materials in parts by weight: 30 parts of polyurethane polyol, 40 parts of α,ω-dihydroxy polydimethylsiloxane, 8 parts of dimethyl phosphite, 18 parts of polyisocyanate, 12 parts of nano silica, 2 parts of silane coupling agent, 0.25 parts of catalyst, and 60 parts of organic solvent.

[0101] In this embodiment, the polyurethane polyol used is polycaprolactone diol with a molecular weight of 3000, the polyisocyanate used is diphenylmethane diisocyanate, the silane coupling agent used is KH-580, and the organic solvent used is tetrahydrofuran.

[0102] The self-cleaning hydrophobic architectural membrane material in this embodiment is made by the following steps:

[0103] Step 1: Under nitrogen protection, 2 parts of silane coupling agent, 12 parts of nano silica, and 120 parts of 40% (v / v) ethanol aqueous solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 60°C for 2 hours. After the reaction was completed, the nano silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano silica.

[0104] The second step involves uniformly mixing polyurethane polyol, α,ω-dihydroxy polydimethylsiloxane, dimethyl phosphite, polyisocyanate, modified nano silica, catalyst, and organic solvent to obtain a composite slurry. The composite slurry is then poured into a mold and heated at 50°C for 40 minutes. After that, the mixture is heated at 100°C for another 120 minutes to obtain a self-cleaning hydrophobic architectural membrane.

[0105] Since the α,ω-dihydroxypolydimethylsiloxane structure in this comparative example does not contain double bonds, it cannot be photocured.

[0106] Experimental Example 1

[0107] Performance tests were conducted on the self-cleaning hydrophobic architectural membrane materials in Examples 1-6 and Comparative Examples 1-2. The tensile strength of each component sample was tested according to GB / T 1040.3-2006 "Determination of Tensile Properties of Plastics - Part 3: Test Conditions for Films and Sheets". The mass loss of each component sample after 500 cycles of abrasion was tested according to GB / T 1768-2006 "Determination of Abrasion Resistance of Paints and Varnishes - Rotating Rubber Grinding Wheel Method". The water contact angle of each component sample was tested according to GB / T 30447-2013 "Method for Measurement of Contact Angle of Nanofilms". The limiting oxygen index of each component sample was tested according to GB / T 2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics". The test results are shown in Table 1.

[0108] Table 1

[0109] project Tensile strength / MPa Loss of mass / mg Water contact angle / ° Limiting oxygen index / % Example 1 10.9 12.4 152 27.1 Example 2 11.2 11.8 150 27.6 Example 3 12.6 10.1 155 28.4 Example 4 13.1 9.5 154 28.7 Example 5 15.2 7.6 158 29.6 Example 6 15.9 7.2 156 30.1 Comparative Example 1 4.1 42.7 142 21.4 Comparative Example 2 3.2 49.2 138 25.6

[0110] As can be seen from Table 1, the self-cleaning hydrophobic architectural membrane materials of the present invention in Examples 1 to 6 have better tensile strength and wear resistance, and the water contact angle is 150° and above, which can achieve a superhydrophobic effect. Combined with Comparative Example 1, it can be seen that the unmodified polysiloxane segments have poor tensile properties, which seriously affects the tensile properties of the membrane material. Moreover, due to the lack of effective linkage between nano-silica and polyurethane network, the wear resistance is poor and the ideal superhydrophobic effect is not achieved. In addition, the addition of flame retardant to Comparative Example 1 will further aggravate the problem of uneven dispersion of raw materials, resulting in a further decrease in mechanical properties and water contact angle.

[0111] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention, including the best mode, and also to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure, characterized in that, It contains the following raw materials: polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, nano silica, silane coupling agent, photoinitiator, catalyst, and organic solvent; The flame-retardant functionalized polysiloxane segments are prepared by the following steps: S1. Hydroxyvinyl polydimethylsiloxane is obtained by catalytic cracking of terminal vinyl polydimethylsiloxane under acidic conditions; S2. Triethylene glycol phosphite is reacted with chloromethyltriethoxysilane via the Eberzoff reaction to obtain a flame-retardant functionalized siloxane crosslinking agent. S3. Hydroxyvinyl polydimethylsiloxane is extended by hydrolysis and condensation reaction using a flame-retardant functionalized siloxane crosslinking agent, and then end-capped with hexamethyldisiloxane to obtain flame-retardant functionalized polysiloxane segments.

2. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The raw materials contain the following parts by weight: 20-30 parts of polyurethane polyol, 20-40 parts of flame-retardant functionalized polysiloxane segments, 12-18 parts of polyisocyanate, 5-12 parts of nano-silica, 0.5-2 parts of silane coupling agent, 1-2 parts of photoinitiator, 0.05-0.25 parts of catalyst, and 40-60 parts of organic solvent.

3. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The polyurethane polyol is polycaprolactone diol with a molecular weight of 2000-3000.

4. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The polyisocyanate is at least one of isophorone diisocyanate and diphenylmethane diisocyanate.

5. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The silane coupling agent is at least one of KH-580 and KH-590.

6. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The catalyst is at least one of dibutyltin dilaurate and stannous octoate.

7. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The organic solvent is tetrahydrofuran.

8. The self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 1, characterized in that, The self-cleaning hydrophobic architectural membrane material is prepared by the following steps: The first step is to graft a silane coupling agent onto the surface of nano-silica to obtain modified nano-silica; The second step involves uniformly mixing polyurethane polyol, flame-retardant functionalized polysiloxane segments, polyisocyanate, modified nano silica, photoinitiator, catalyst, and organic solvent to obtain a composite slurry. The composite slurry is then poured into a mold and undergoes pre-curing, photo-curing, and final curing to obtain a self-cleaning hydrophobic architectural membrane.

9. A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 8, characterized in that, The method for grafting silane coupling agents onto the surface of nano-silica is as follows: Under nitrogen protection, silane coupling agent, nano-silica, and 40-80% (v / v) aqueous ethanol solution were mixed in a reaction vessel. After stirring, the mixture was reacted at 40-60°C for 2-3 hours. After the reaction was completed, the nano-silica was filtered out and washed with anhydrous ethanol and deionized water in sequence, and then dried to obtain modified nano-silica.

10. A self-cleaning hydrophobic architectural membrane material with a micro-nano rough structure according to claim 8, characterized in that, The pre-curing conditions are as follows: heating reaction at 40–50°C for 40–60 minutes; the photocuring conditions are as follows: photocuring at an intensity of 10–50 mW / cm². 2 Irradiate under ultraviolet light for 5–15 min; the final curing condition is to heat and react at a temperature of 80–100℃ for 120–180 min.