Waterproof and moisture-permeable coating film, method for preparing the same, and use thereof

Abstract

This application discloses a waterproof and breathable coating film, its preparation method, and its application, belonging to the field of membrane materials. A waterproof and breathable coating film is prepared from raw materials comprising the following parts by weight: 45-50 parts polyurethane resin; 33-42 parts organic solvent; 1-3 parts aerogel; and 0.5-2 parts dispersant. The polyurethane resin is prepared from raw materials comprising the following parts by weight: 40-50 parts polyethylene glycol; 7.5-15 parts polytetramethylene ether glycol; 30-35 parts diisocyanate; and 8-10 parts chain extender. This application has the advantage of achieving both waterproof and breathable wicking effects while obtaining good thermal insulation properties.

Description

Technical Field

[0001] This application relates to the field of membrane materials, and in particular to a waterproof and breathable coating film, its preparation method, and its application. Background Technology

[0002] With the rise of outdoor sports, the market demand for clothing such as waterproof jackets and life-saving protective clothing has increased significantly. Most waterproof jackets or life-saving protective clothing sold on the market are made of composite fiber materials. Composite fiber materials are mainly a combination of modified bamboo fiber and other chemical fibers. Composite fiber materials rely on the resin coating on the surface to achieve their corresponding functions.

[0003] In outdoor sports, clothing needs to be waterproof to cope with rainy weather and breathable to handle the sweating process during exercise. As outdoor sports become more widespread, the requirements for clothing are also increasing. Therefore, clothing also needs to be able to cope with high altitude and low temperature environments. Thus, the heat insulation effect of the resin coating on the surface of clothing is particularly important.

[0004] While current coatings achieve waterproofing and breathability, they often fail to provide adequate thermal insulation, thus limiting their application. Summary of the Invention

[0005] In order to achieve both waterproof and breathable wicking effects while obtaining good heat insulation and heat preservation effects, this application provides a waterproof and breathable coating film, its preparation method and its application.

[0006] Firstly, the waterproof and breathable coating provided in this application adopts the following technical solution:

[0007] A waterproof and breathable coating film is prepared from raw materials comprising the following parts by weight:

[0008] 45-50 parts of polyurethane resin;

[0009] 33-42 parts of organic solvent;

[0010] 1-3 parts of aerogel;

[0011] Dispersant 0.5–2 parts;

[0012] The polyurethane resin is prepared from raw materials comprising the following parts by weight:

[0013] 40-50 parts of polyethylene glycol;

[0014] 7.5–15 parts of polytetramethylene ether glycol;

[0015] 30-35 parts of diisocyanate;

[0016] Chain extender 8-10 parts.

[0017] By adopting the above technical solution, aerogel is added to polyurethane resin. Aerogel has high porosity, low density, and large specific surface area, thus possessing a low thermal conductivity, which can improve the thermal insulation performance of the polyurethane coating. However, for polyurethane coatings requiring waterproofing and breathability, the addition of aerogel affects the pore size and distribution of the coating, thereby affecting its waterproofing and breathability. Based on this, the coating of this application uses polyurethane resin prepared from the above-mentioned proportions as a base, with polyethylene glycol and polytetramethylene ether glycol compounded as a polyether diol. This gives the polyurethane resin itself high waterproofing and breathability. Furthermore, the polyurethane resin achieves good compatibility with the aerogel, dispersing the aerogel while ensuring a good arrangement between the aerogel particles. This not only extends the heat transfer path and fully utilizes the thermal insulation effect of the aerogel but also reduces the negative impact of the aerogel on the micropore structure of the coating, ensuring the coating's water pressure resistance and moisture permeability. Therefore, while achieving waterproofing and breathability, it also obtains good thermal insulation performance.

[0018] Optionally, the number average molecular weight of the polyethylene glycol is 2000-6000, and the number average molecular weight of the polytetramethylene ether glycol is 1000-3000.

[0019] Optionally, the number average molecular weight of the polyethylene glycol is 4000-5000, and the number average molecular weight of the polytetramethylene ether glycol is 2000-2500.

[0020] By adopting the above technical solution, the number-average molecular weight matching of polyethylene glycol and polytetramethylene ether glycol is optimized, ensuring the waterproof and breathable performance of the coating film while improving the interfacial compatibility with aerogel, ensuring that the mechanical properties of the coating film meet the standards, and fully utilizing the heat insulation effect of aerogel, thus making it applicable to the surface of clothing such as rain jackets.

[0021] Optionally, the diisocyanate includes one or both of 4',4-diphenylmethane diisocyanate and 2',4-diphenylmethane diisocyanate.

[0022] Optionally, the chain extender includes one or both of 1,4-butanediol and 1,6-hexanediol.

[0023] Optionally, the aerogel is a silica-based aerogel.

[0024] By adopting the above technical solutions, silicon-based aerogels exhibit excellent stability and continuously provide thermal insulation functions.

[0025] Optionally, the aerogel includes one or both of silica aerogel and silicon carbide aerogel.

[0026] Optionally, the specific surface area of ​​the aerogel is 600–750 m².2 / g, the density of the aerogel is 0.07~0.10g / cm³. 3 .

[0027] By adopting the above technical solution, aerogel is prepared through sol-gel and drying, thereby forming a microporous network structure. It has the advantages of high specific surface area and low density, and performs well in terms of heat insulation. However, it also brings the problem of easy spontaneous aggregation. With the special polyurethane resin and dispersant of this application, the dispersion stability of aerogel in the film-forming system is promoted. After thorough stirring, the occurrence of spontaneous aggregation is reduced. Thus, the coating film obtains good heat insulation effect while ensuring waterproof and breathable performance.

[0028] Optionally, the dispersant may be a graft copolymer dispersant.

[0029] By adopting the above technical solution, the segment grafting combination of the dispersant improves the compatibility between the aerogel and the polyurethane film-forming segments, thereby improving the dispersibility of the aerogel, forming a stable thermal insulation network structure, and controlling the size and distribution of the membrane micropores, thus improving the thermal insulation performance and waterproof and breathable performance.

[0030] Preferably, the dispersant is a graft copolymer dispersant with a nonlinear comb-like structure.

[0031] By adopting the above technical solution, the nonlinear comb-like structure in the dispersant helps to further improve the dispersion uniformity of the aerogel.

[0032] Optionally, the organic solvent includes one or both of N,N-dimethylformamide and ethyl acetate.

[0033] Optionally, the raw materials include 18 to 22 parts by weight of N,N-dimethylformamide and 15 to 20 parts by weight of ethyl acetate.

[0034] By adopting the above technical solution, the choice of organic solvent will affect the curing process of the coating film. Therefore, by selecting a specific ratio of N,N-dimethylformamide and ethyl acetate as organic solvent, the evaporation rate of organic solvent can be better controlled while fully dispersing the raw materials, so that the micropore structure during film formation is more in line with the requirements of waterproof and breathable membrane.

[0035] Optionally, the raw materials may also include one or more of matting agents, antioxidants, and UV stabilizers.

[0036] By adopting the above technical solutions, the matting agent can adjust the gloss of the coating according to the design requirements of the coating; the antioxidant and anti-ultraviolet agent can resist the interference of the external environment to a certain extent, so as to improve the durability of the coating.

[0037] Optionally, the matting agent included in the raw material is 1 to 3 parts by weight, and the matting agent is selected from fumed silica.

[0038] By adopting the above technical solutions, fumed silica is prepared by high-temperature sintering or vapor deposition. For example, silicon halides are hydrolyzed at high temperature in an oxyhydrogen flame to generate extremely fine fumed silica particles with a denser structure and higher density, resulting in good light-shielding effect.

[0039] Secondly, the method for preparing a waterproof and breathable coating provided in this application adopts the following technical solution:

[0040] A method for preparing a waterproof and breathable coating film includes the following steps:

[0041] Polyethylene glycol and polytetramethylene ether glycol are mixed, protected by an inert gas, heated, and then diisocyanate is added for prepolymerization. A chain extender is then added to continue the reaction, and the product is discharged to obtain polyurethane resin.

[0042] The polyurethane resin, organic solvent, aerogel and dispersant are mixed, stirred and dispersed evenly, and degassed to obtain a polyurethane slurry.

[0043] The polyurethane slurry is applied to the surface of the release material, dried, and separated to obtain a waterproof and breathable coating film.

[0044] Thirdly, the application of the waterproof and breathable coating provided in this application adopts the following technical solution:

[0045] An application of a waterproof and breathable coating, wherein the waterproof and breathable coating is applied to the surface layer of clothing.

[0046] Optionally, the waterproof and breathable coating is applied to the surface layer of the garment by first forming a film on the surface of the release material and then bonding or sewing it to the fabric surface of the garment.

[0047] Optionally, the waterproof and breathable coating is applied to the surface layer of the garment by impregnating the fabric surface with adhesive to form a film.

[0048] In summary, this application has the following beneficial effects:

[0049] 1. This application incorporates aerogel into polyurethane resin. Aerogel has high porosity, low density, and large specific surface area, resulting in a low thermal conductivity and improved thermal insulation performance of the polyurethane coating. However, for polyurethane coatings requiring waterproofing and breathability, the addition of aerogel affects the pore size and distribution, thus impacting waterproofing and breathability. Therefore, the coating of this application uses a polyurethane resin prepared from the above-mentioned proportions as a base, with polyethylene glycol and polytetramethylene ether glycol compounded as a polyether diol. This gives the polyurethane resin itself high waterproofing and breathability. Furthermore, the polyurethane resin achieves good compatibility with the aerogel, dispersing the aerogel while ensuring a good arrangement between them. This not only extends the heat transfer path and fully utilizes the thermal insulation effect of the aerogel but also reduces the negative impact of the aerogel on the micropore structure of the coating, ensuring the coating's water pressure resistance and moisture permeability. Thus, while achieving waterproofing and breathability, it also provides excellent thermal insulation.

[0050] 2. This application optimizes the number-average molecular weight ratio of polyethylene glycol and polytetramethylene ether glycol as well as the size of the aerogel, ensuring the waterproof and breathable performance of the coating while improving the interfacial compatibility with the aerogel, ensuring that the mechanical properties of the coating meet the standards, and fully utilizing the thermal insulation effect of the aerogel, thus making it applicable to the surface of clothing such as rain jackets. Attached Figure Description

[0051] Figure 1 This is a photograph of the waterproof and breathable coating film prepared in Example 1 of this application. Detailed Implementation

[0052] The following is in conjunction with the appendix Figure 1 This application will be described in further detail.

[0053] Example 1

[0054] A method for preparing a waterproof and breathable coating film includes the following steps:

[0055] Weigh out 4 kg of polyethylene glycol, 1.5 kg of polytetramethylene ether glycol, 3 kg of 4,4'-diphenylmethane diisocyanate, and 0.8 kg of 1,4-butanediol. The number average molecular weight of polyethylene glycol is 2000, and the number average molecular weight of polytetramethylene ether glycol is 3000.

[0056] Polyethylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, followed by the addition of 1,4-butanediol and a further 2 hours of reaction. The residual amount of -NCO groups was measured, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was then discharged to obtain polyurethane resin.

[0057] Weigh out 4.5 kg of the polyurethane resin, 0.1 kg of silica aerogel, 0.05 kg of dispersant, 1.8 kg of N,N-dimethylformamide, 1.5 kg of ethyl acetate, 0.1 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer. The silica aerogel has a specific surface area of ​​600 m² / kg. 2 / g, density is 0.10g / cm³ 3 The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0058] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0059] Polyurethane slurry was applied to the surface of release paper by roller coating, dried at 130℃, and separated to obtain a waterproof and breathable coating film with a thickness of 0.03mm. Figure 1 As shown.

[0060] Example 2

[0061] A method for preparing a waterproof and breathable coating film includes the following steps:

[0062] Weigh out 5 kg of polyethylene glycol, 0.75 kg of polytetramethylene ether glycol, 3.5 kg of 4,4'-diphenylmethane diisocyanate, and 1 kg of 1,4-butanediol. The number average molecular weight of polyethylene glycol is 6000, and the number average molecular weight of polytetramethylene ether glycol is 1000.

[0063] Polyethylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, followed by the addition of 1,4-butanediol and a further 2 hours of reaction. The residual amount of -NCO groups was measured, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was then discharged to obtain polyurethane resin.

[0064] Weigh out 5 kg of the polyurethane resin, 0.3 kg of silica aerogel, 0.2 kg of dispersant, 2.2 kg of N,N-dimethylformamide, 2 kg of ethyl acetate, 0.3 kg of fumed silica, 0.02 kg of antioxidant, and 0.03 kg of UV stabilizer. The silica aerogel has a specific surface area of ​​600 m² / kg. 2 / g, density is 0.10g / cm³ 3The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0065] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0066] Polyurethane slurry was applied to the surface of release paper by roller coating, dried at 130℃, and separated to obtain a waterproof and breathable coating film with a thickness of 0.03mm.

[0067] Example 3

[0068] A method for preparing a waterproof and breathable coating film includes the following steps:

[0069] Weigh out 4.5 kg of polyethylene glycol, 1 kg of polytetramethylene ether glycol, 3.3 kg of 4,4'-diphenylmethane diisocyanate, and 0.9 kg of 1,4-butanediol. The number average molecular weight of polyethylene glycol is 3000, and the number average molecular weight of polytetramethylene ether glycol is 2500.

[0070] Polyethylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, followed by the addition of 1,4-butanediol and a further 2 hours of reaction. The residual amount of -NCO groups was measured, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was then discharged to obtain polyurethane resin.

[0071] Weigh out 4.6 kg of the polyurethane resin, 0.25 kg of silica aerogel, 0.1 kg of dispersant, 2 kg of N,N-dimethylformamide, 1.8 kg of ethyl acetate, 0.2 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer. The silica aerogel has a specific surface area of ​​750 m² / kg. 2 / g, density is 0.07g / cm³ 3 The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0072] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0073] Polyurethane slurry was applied to the surface of release paper by roller coating, dried at 130℃, and separated to obtain a waterproof and breathable coating film with a thickness of 0.03mm.

[0074] Example 4

[0075] A method for preparing a waterproof and breathable coating.

[0076] The difference between this embodiment and Embodiment 3 lies in the different polyurethane resins.

[0077] Specifically, weigh out 4.5 kg of polyethylene glycol, 1 kg of polytetramethylene ether glycol, 3.3 kg of 4,4'-diphenylmethane diisocyanate, and 0.9 kg of 1,4-butanediol. The number average molecular weight of polyethylene glycol is 4000, and the number average molecular weight of polytetramethylene ether glycol is 2000.

[0078] Polyethylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, followed by the addition of 1,4-butanediol and a further 2 hours of reaction. The residual amount of -NCO groups was measured, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was then discharged to obtain polyurethane resin.

[0079] Example 5

[0080] A method for preparing a waterproof and breathable coating.

[0081] The difference between this embodiment and Embodiment 3 lies in the different polyurethane resins.

[0082] Specifically, weigh out 4.5 kg of polyethylene glycol, 1 kg of polytetramethylene ether glycol, 3.3 kg of 4,4'-diphenylmethane diisocyanate, and 0.9 kg of 1,4-butanediol. The number average molecular weight of polyethylene glycol is 5000, and the number average molecular weight of polytetramethylene ether glycol is 2500.

[0083] Polyethylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, followed by the addition of 1,4-butanediol and a further 2 hours of reaction. The residual amount of -NCO groups was measured, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was then discharged to obtain polyurethane resin.

[0084] Example 6

[0085] A method for preparing a waterproof and breathable coating.

[0086] The difference between this embodiment and Embodiment 3 lies in the different polyurethane slurry.

[0087] Specifically, 4.6 kg of the polyurethane resin, 0.25 kg of silica aerogel, 0.1 kg of dispersant, 2 kg of N,N-dimethylformamide, 1.8 kg of ethyl acetate, 0.2 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer prepared in Example 3 were weighed. The silica aerogel had a specific surface area of ​​750 m² / kg. 2 / g, density is 0.07g / cm³ 3 The dispersant is an anionic graft copolymer dispersant, model SPE 108; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0088] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0089] Example 7

[0090] A method for preparing a waterproof and breathable coating.

[0091] The difference between this embodiment and Embodiment 3 lies in the different polyurethane slurry.

[0092] Specifically, 4.6 kg of the polyurethane resin, 0.25 kg of silica aerogel, 0.1 kg of dispersant, 2 kg of N,N-dimethylformamide, 1.8 kg of ethyl acetate, 0.2 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer prepared in Example 3 were weighed. The silica aerogel had a specific surface area of ​​850 m² / kg. 2 / g, density is 0.06g / cm³ 3 The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0093] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0094] Example 8

[0095] A method for preparing a waterproof and breathable coating.

[0096] The difference between this embodiment and Embodiment 3 lies in the different polyurethane slurry.

[0097] Specifically, 4.6 kg of the polyurethane resin, 0.25 kg of silica aerogel, 0.1 kg of dispersant, 2 kg of N,N-dimethylformamide, 1.8 kg of ethyl acetate, 0.2 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer prepared in Example 3 were weighed. The silica aerogel had a specific surface area of ​​500 m² / kg. 2 / g, density is 0.11g / cm³ 3 The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0098] Polyurethane resin, silica aerogel, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0099] Example 9

[0100] A method for preparing a waterproof and breathable coating.

[0101] The difference between this embodiment and Embodiment 3 lies in the different polyurethane slurry.

[0102] Specifically, 4.6 kg of the polyurethane resin, 0.25 kg of silica aerogel, 0.1 kg of dispersant, 2 kg of methyl ethyl ketone (MEK), 1.8 kg of ethyl acetate, 0.2 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer were weighed out according to Example 3. The silica aerogel had a specific surface area of ​​750 m² / kg. 2 / g, density is 0.07g / cm³ 3 The dispersant is a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of fumed silica is 80 nm; the antioxidant is antioxidant 1010; and the UV stabilizer is UV531.

[0103] Polyurethane resin, silica aerogel, dispersant, methyl ethyl ketone, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at high speed of 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0104] Comparative Example 1

[0105] A method for preparing a waterproof and breathable coating.

[0106] The difference between this comparative example and Example 3 lies in the different polyurethane slurry.

[0107] Specifically, 4.6 kg of the polyurethane resin prepared in Example 3, 0.1 kg of dispersant, 2 kg of N,N-dimethylformamide, 1.8 kg of ethyl acetate, 0.45 kg of fumed silica, 0.01 kg of antioxidant, and 0.02 kg of UV stabilizer were weighed. The dispersant was a non-linear comb-structured graft copolymer dispersant, model SPE 107-1; the average particle size of the fumed silica was 80 nm; the antioxidant was antioxidant 1010; and the UV stabilizer was UV531.

[0108] Polyurethane resin, dispersant, N,N-dimethylformamide, ethyl acetate, fumed silica, antioxidant, and UV stabilizer are mixed and dispersed at 1300 rpm for 30 min, followed by vacuum degassing to obtain polyurethane slurry.

[0109] Comparative Example 2

[0110] A method for preparing a waterproof and breathable coating.

[0111] The difference between this comparative example and Example 3 lies in the different polyurethane resins.

[0112] Specifically, weigh out 4.5 kg of polyethylene glycol, 1 kg of polypropylene glycol, 3.3 kg of 4,4'-diphenylmethane diisocyanate, and 0.9 kg of 1,4-butanediol. The number average molecular weight of both polyethylene glycol and polypropylene glycol is 3000.

[0113] Polyethylene glycol and polypropylene glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, then 1,4-butanediol was added and the reaction continued for 2 hours. The residual amount of -NCO groups was detected, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was discharged to obtain polyurethane resin.

[0114] Comparative Example 3

[0115] A method for preparing a waterproof and breathable coating.

[0116] The difference between this comparative example and Example 3 lies in the different polyurethane resins.

[0117] Specifically, weigh out 4.5 kg of polypropylene glycol, 1 kg of polytetramethylene ether glycol, 3.3 kg of 4,4'-diphenylmethane diisocyanate, and 0.9 kg of 1,4-butanediol. The number average molecular weight of polypropylene glycol is 3000, and the number average molecular weight of polytetramethylene ether glycol is 2500.

[0118] Polypropylene glycol and polytetramethylene ether glycol were mixed and protected with nitrogen gas. The reaction system was heated to 80°C, 4,4'-diphenylmethane diisocyanate was added and prepolymerized for 2 hours, then 1,4-butanediol was added and the reaction continued for 2 hours. The residual amount of -NCO groups was detected, and di-n-butylamine was added to consume the residual 4,4'-diphenylmethane diisocyanate. The product was discharged to obtain polyurethane resin.

[0119] Performance testing:

[0120] Water pressure resistance test: Refer to the hydrostatic pressure test B of JIS L1092 "Textiles Water Resistance" to conduct a water pressure resistance test on the waterproof and breathable coating. The test results are shown in Table 1.

[0121] Moisture permeability test: The moisture permeability of the waterproof and breathable coating was tested according to JIS L1099 B1 (potassium acetate-inverted cup method). The test results are shown in Table 1.

[0122] Thermal conductivity test: The thermal conductivity of the waterproof and breathable coating was tested using a thermal conductivity tester. The test results are shown in Table 1.

[0123] Table 1

[0124]

[0125]

[0126] Based on the test results of water pressure resistance, moisture permeability and thermal conductivity, it can be seen that the coatings of Examples 1-3 all have the advantages of high water pressure resistance, high moisture permeability and low thermal conductivity, which meet the performance requirements of waterproof, breathable and heat-insulating clothing such as rain jackets.

[0127] Comparing Comparative Example 1 with Example 3, it can be seen that when only fumed silica is filled in the coating, the thermal conductivity of the coating is high, greater than 0.12 W / m·K, which does not meet the requirements of thermal insulation materials and is difficult to meet the thermal insulation requirements of clothing such as rain jackets. This indicates that aerogel plays an excellent thermal insulation role in the coating, and the low density of aerogel reduces the impact on the waterproof and breathable performance of the coating.

[0128] Comparing Comparative Examples 2-3 with Example 3, it can be seen that when the polyether diol is a blend of polyethylene glycol and polytetramethylene ether diol, the resulting polyurethane resin not only maintains the stability of the micropores in the coating film, thus achieving a good balance between water pressure resistance and moisture permeability, but also exhibits the best compatibility with aerogel, promoting the full dispersion of aerogel and the formation of a stable thermal insulation network structure, significantly reducing the thermal conductivity of the coating film, and improving its thermal insulation performance.

[0129] Comparing Example 3 with Examples 4-5, it can be seen that when polyethylene glycol and polytetramethylene ether glycol with specific molecular weight combinations are used, the polyurethane segment structure of the coating and the dispersion structure of the aerogel are further optimized, which can further improve the water pressure resistance of the coating and reduce the thermal conductivity of the coating, thereby promoting waterproof and heat insulation effects.

[0130] Comparing Example 3 with Example 6, it can be seen that the nonlinear comb-shaped graft copolymer dispersant has a better dispersion effect on aerogel and promotes the reduction of the thermal conductivity of the coating film.

[0131] Comparing Example 3 with Examples 7-8, it can be seen that when the size parameters of the aerogel are maintained within a specific range, the thermal conductivity of the coating film can be kept below 0.05 W / m·K, meeting the requirements of high-efficiency thermal insulation materials. Furthermore, suitable size parameters improve the compatibility between the aerogel and the polyurethane chain segments, ensuring that the waterproof and breathable effect of the coating film is at a good level.

[0132] Comparing Example 3 with Example 9, it can be seen that the volatility characteristics of organic solvents affect the formation of the coating film. Therefore, the selection of organic solvents has a certain impact on the final waterproof, breathable, and heat-insulating effects of the coating film.

[0133] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A waterproof and breathable coating, characterized in that: It is prepared from raw materials comprising the following parts by weight: 45-50 parts of polyurethane resin; 33-42 parts of organic solvent; 1-3 parts of aerogel; Dispersant 0.5~2 parts; The polyurethane resin is prepared from raw materials comprising the following parts by weight: 40-50 parts of polyethylene glycol; 7.5-15 parts of polytetramethylene ether glycol; 30-35 parts of diisocyanate; Chain extender 8-10 parts; The specific surface area of ​​the aerogel is 600~750m². 2 / g, the density of the aerogel is 0.07~0.10 g / cm³. 3 ; The dispersant is selected from graft copolymer dispersants with a nonlinear comb-like structure.

2. The waterproof and breathable coating according to claim 1, characterized in that: The number average molecular weight of the polyethylene glycol is 2000-6000, and the number average molecular weight of the polytetramethylene ether glycol is 1000-3000.

3. The waterproof and breathable coating according to claim 2, characterized in that: The number average molecular weight of the polyethylene glycol is 4000-5000, and the number average molecular weight of the polytetramethylene ether glycol is 2000-2500.

4. The waterproof and breathable coating according to claim 1, characterized in that: The organic solvent includes one or both of N,N-dimethylformamide and ethyl acetate.

5. A waterproof and breathable coating according to any one of claims 1-4, characterized in that: The raw materials also include one or more of the following: matting agents, antioxidants, and UV stabilizers.

6. The waterproof and breathable coating according to claim 5, characterized in that: The raw materials contain 1 to 3 parts by weight of matting agent, and the matting agent is selected from fumed silica.

7. A method for preparing a waterproof and breathable coating film according to any one of claims 1-6, characterized in that: Includes the following steps: Polyethylene glycol and polytetramethylene ether glycol are mixed, protected by an inert gas, heated, and then diisocyanate is added for prepolymerization. A chain extender is then added to continue the reaction, and the product is discharged to obtain polyurethane resin. The polyurethane resin, organic solvent, aerogel and dispersant are mixed, stirred and dispersed evenly, and degassed to obtain a polyurethane slurry. The polyurethane slurry is applied to the surface of the release material, dried, and separated to obtain a waterproof and breathable coating film.

8. The application of a waterproof and breathable coating film according to any one of claims 1-6, characterized in that: The waterproof and breathable coating is applied to the surface layer of clothing.

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