Building waterproof composite fabric with one-way moisture conducting function and preparation method thereof

Abstract

This invention discloses a waterproof composite fabric for buildings with unidirectional moisture-wicking function and its preparation method, belonging to the technical field of unidirectional moisture-wicking materials. It comprises, from bottom to top, a PVDF hydrophobic layer, a polyester and cellulose blended nonwoven fabric transport layer, and a PVA nanofiber hydrophilic layer. The optimal blending ratio of polyester and cellulose in this invention is 6:4, the electrospinning voltage is 22~24kV, and the spraying time is 1~4h; the moisture permeability of the composite fabric is ≥3800g / (m³). 2 • h); After exposure to temperatures ranging from -20℃ to 60℃ and 500 hours of ultraviolet radiation, the retention rate of both waterproof and moisture-wicking properties is ≥90%; the moisture wicking capacity reaches 2800g / (m²). 2 Compared to traditional SBS modified bitumen waterproof membranes, this invention offers a 670% improvement in tensile strength, a 30% reduction in weight per unit area, and a tensile strength of 8.5 MPa. It solves the synergistic problem of waterproofing and moisture removal in outdoor building environments, exhibiting strong process controllability and broad application prospects.

Description

Technical Field

[0001] This invention belongs to the field of unidirectional moisture-wicking materials, and in particular relates to a building waterproof composite fabric with unidirectional moisture-wicking function and its preparation method, which can be widely used in building outdoor waterproof membranes and related waterproof and moisture-proof projects. Background Technology

[0002] One-way moisture-wicking fabrics are functional materials that spontaneously transport liquids from one side to the other through differential capillary action or wetting gradient effects, while simultaneously preventing liquid transport in the opposite direction. Traditional one-way breathable fabrics often rely on pore size gradient design to achieve directional liquid transport, but these fabrics typically use fibers with high moisture absorption, resulting in low drying rates and failing to meet the long-term needs of building environments. Newer one-way breathable fabrics construct wetting gradients using hydrophilic and hydrophobic yarns, typically choosing polypropylene as the hydrophobic yarn and polyester as the hydrophilic yarn. While this improves moisture wicking performance, polyester itself has poor hydrophilicity, resulting in insufficient moisture absorption and making it unsuitable for the long-term humid outdoor environment of buildings. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a building waterproof composite fabric with unidirectional moisture wicking and waterproofing synergy, and a method for preparing the same.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: a building waterproof composite fabric with one-way moisture-wicking function, comprising a composite fabric body, wherein the composite fabric body comprises, from bottom to top, a polyvinylidene fluoride (PVDF) hydrophobic layer, a polyester and cellulose blended nonwoven fabric transport layer, and a polyvinyl alcohol (PVA) nanofiber hydrophilic layer.

[0005] Furthermore, in the polyester and cellulose blended nonwoven transport layer, the mass ratio of polyester to cellulose is 5:5 to 7:3. The transport layer is treated with a fabric hydrophilic finishing agent with a concentration of 5 to 10 g / 100 mL, and the water diffusion rate is 0.18 to 0.21 cm / s. The PVA nanofiber hydrophilic layer has a fiber diameter of 200 to 300 nm, a porosity of 60% to 70%, and is cross-linked with glutaraldehyde acetone solution. The PVDF hydrophobic layer has a water contact angle ≥135°, a waterproof rating of IPX7, and a thickness of 20 to 30 μm.

[0006] Furthermore, when the mass ratio of polyester to cellulose is 6:4, the moisture permeability of the composite fabric body is ≥3800g / (m³). 2 (·h), after exposure to temperatures ranging from -20℃ to 60℃ and 500 hours of ultraviolet radiation, the retention rate of waterproof and moisture-wicking properties is ≥90%; the unit area weight of the composite fabric is 1.2 kg / m². 2 Tensile strength ≥ 8.5 MPa.

[0007] This invention also provides a method for preparing a building waterproof composite fabric with unidirectional moisture-wicking function, comprising the following steps: Preparation of the transport layer of S1, polyester and cellulose blended nonwoven fabric: S11. Preparation of spunlace nonwoven fabric: The spunlace nonwoven fabric includes polyester fiber and cellulose fiber, and the blending mass ratio of polyester fiber and cellulose fiber is 5:5~7:3.

[0008] Furthermore, the blending mass ratio of the polyester fiber and cellulose fiber is 6:4.

[0009] At this ratio, the moisture diffusion rate of the transport layer reaches 0.21 cm / s, which is 1.5 to 1.8 times that of a single fiber, and it can form the best synergistic effect with the subsequent PVA nanofibers.

[0010] S12. Preparation of transport layer: Take a hydrophilic finishing agent for fabric with a concentration of 5~10g / 100mL, add deionized water and stir mechanically for 1~2h to obtain a finishing agent solution; immerse the blended spunlace nonwoven fabric in the finishing agent solution for 6~12h, and then dry it in a vacuum oven at 80~120℃ for 2~3h to obtain the transport layer.

[0011] Furthermore, the concentration of the hydrophilic finishing agent for the fabric is 7g / 100mL. The hydrophilic finishing agent for the fabric is a polyester polyether. The spunlace nonwoven fabric made by blending is immersed in the finishing agent solution for 10h, and then dried in a vacuum oven at 85℃ for 2h.

[0012] The transport layer processed by the above technology has a stable moisture diffusion rate of 0.18~0.21cm / s, which can efficiently receive and transport moisture.

[0013] S2. Preparation of the hydrophilic layer of polyvinyl alcohol (PVA): S21. Preparation of spinning solution: Mix PVA particles with deionized water to prepare a spinning solution with a concentration of 10~15g / 100mL. Mechanically stir at 80~95℃ for 6~8h to ensure that the PVA particles are completely melted. Then let it stand for 1~2h to remove bubbles from the spinning solution to ensure the quality of fiber forming.

[0014] Furthermore, PVA particles were mixed with deionized water to prepare a spinning solution with a concentration of 12 g / 100 mL, and mechanically stirred at 90 °C for 7 h.

[0015] S22, Electrospinning process: Control the spinning environment temperature to 25~30℃, relative humidity to 30%~35%, set the spinning voltage to 22~24kV, feed speed to 0.6~0.7ml / h, and working distance to 15~20cm; electrospin the spinning solution obtained in step S21 onto the upper surface of the transport layer obtained in step S1 to form a PVA nanofiber layer.

[0016] Furthermore, the PVA layer porosity is 60-70% when the spinning voltage is 22-24kV; the feed speed is 0.65ml / h; and the working distance is 18cm.

[0017] S23, Crosslinking treatment: The double-layer fabric-PVA nanofiber layer obtained in step S22 is crosslinked. The PVA nanofiber hydrophilic layer was obtained by immersing the nanofiber in a glutaraldehyde-acetone solution with pH=2 and crosslinking at room temperature for 1-2 hours. After rinsing with plenty of deionized water to remove residual reagents, the nanofiber was dried.

[0018] Furthermore, the glutaraldehyde concentration in the glutaraldehyde-acetone solution is 2 g / 100 mL; crosslinking is performed at room temperature for 1.5 h.

[0019] The PVA nanofibers in the hydrophilic layer have a diameter of 200-300 nm, which form a synergistic capillary effect with the transport layer to improve moisture absorption and wicking efficiency.

[0020] S3. Preparation of the hydrophobic layer of polyvinylidene fluoride (PVDF): S31. Preparation of spraying solution: Dissolve PVDF powder in a mixed solvent of N,N-dimethylformamide and acetone to prepare a spraying solution with a concentration of 5~10g / 100mL. Stir at room temperature for 10~12h to ensure that the PVDF powder is completely dissolved.

[0021] Furthermore, a spraying solution with a concentration of 8 g / 100 mL was prepared by mixing N,N-dimethylformamide and acetone in a weight ratio of 7:3 and stirring at room temperature for 11 h.

[0022] S32, Electrostatic spraying process: Control the spraying environment temperature to 25~30℃, relative humidity to 30%~35%, set the spraying voltage to 16~18kV, the advance speed to 1.5ml / h, the working distance to 10~15cm, and the spraying time to 1~4h; electrostatically spray the spraying liquid obtained in step S31 onto the lower surface of the transport layer to obtain a PVDF hydrophobic layer.

[0023] Furthermore, the spraying voltage is 17kV; the spraying time is 2h.

[0024] The PVDF hydrophobic layer has a water contact angle ≥135°, a waterproof rating of IPX7, and a thickness of 20~30μm. It can effectively block external moisture intrusion without affecting the expulsion of internal moisture.

[0025] The beneficial effects of this invention are as follows: (1) Material Innovation: The optimal blending ratio of polyester-cellulose (6:4) and the average diameter of PVA nanofibers (240nm) were clearly defined, solving the problem of randomness in material selection and significantly improving the interlayer moisture-wicking synergistic effect, resulting in a moisture permeability rate of 3800g / (m 2 ·h), which improves efficiency by more than 80% compared to single materials.

[0026] PVA, a typical hydrophilic polymer, exhibits strong intermolecular hydrogen bonding, high solution viscosity, and is easily formed into films using electrospinning technology. Its abundant hydroxyl groups also contribute to its extremely strong hygroscopic properties. Furthermore, PVA fibers possess advantages such as high strength, good chemical stability, excellent thermal stability, and low toxicity, making them significant for improving the hygroscopic performance of composite fabrics. Polyester-cellulose blended spunlace nonwoven fabric combines the high strength, abrasion resistance, aging resistance, and corrosion resistance of polyester with the strong water absorption, soft touch, and rapid moisture diffusion of cellulose, achieving an organic combination of durability and high absorbency.

[0027] (2) Process optimization: Quantify the correspondence between process parameters such as electrospinning voltage and spraying distance and the porosity of PVA nanofiber hydrophilic layer and the density of PVDF hydrophobic layer, and solve the problem of waterproofing and moisture conduction balance in a targeted manner. The process is highly controllable and suitable for large-scale production.

[0028] (3) Performance advantages: The product's moisture permeability rate, environmental stability, and lightweight properties are all superior to existing building waterproofing materials, with a moisture conductivity of 2800g / (m²). 2 It boasts a 670% improvement over traditional roll materials, a 30% weight reduction, a tensile strength of 8.5 MPa, and a performance retention rate of ≥90% after 500 hours of UV exposure in environments ranging from -20℃ to 60℃, making it suitable for complex outdoor building environments.

[0029] (4) Application value: It provides a new and efficient solution for building waterproof membranes, effectively solving the problems of moisture retention, heavy weight and poor weather resistance of traditional membranes. It can be widely used in outdoor waterproofing and damp-proofing projects of buildings, and has broad application prospects.

[0030] As can be seen, by determining the blending ratio of polyester and cellulose, the parameters of PVA nanofibers and the process conditions, this invention utilizes the synergistic effect of the high diffusion rate of the blended nonwoven fabric and the strong capillary force of the PVA nanofiber membrane, combined with the construction of a wetting gradient by the PVDF hydrophobic layer, to solve the problems of insufficient moisture wicking and waterproofing balance and poor environmental adaptability of existing products, thereby achieving efficient unidirectional moisture wicking and waterproofing synergy and improving the comprehensive performance of building waterproof membranes. Detailed Implementation

[0031] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the preferred embodiments.

[0032] Example 1 A method for preparing a building waterproof composite fabric with unidirectional moisture-wicking function includes the following steps: Preparation of the transport layer of S1, polyester and cellulose blended nonwoven fabric: S11. Preparation of spunlace nonwoven fabric: The spunlace nonwoven fabric includes polyester fiber and cellulose fiber, and the blending mass ratio of polyester fiber and cellulose fiber is 7:3. S12. Preparation of transport layer: Take a 7g / 100mL hydrophilic finishing agent for fabric, add deionized water and stir mechanically for 2h to obtain a finishing agent solution; immerse the blended spunlace nonwoven fabric in the finishing agent solution for 10h, and then dry it in a vacuum oven at 90℃ for 2h to obtain the transport layer.

[0033] The moisture diffusion rate of the transport layer treated by the above process is stable at 0.19 cm / s.

[0034] Preparation of S2 and PVA nanofiber hydrophilic layers: S21. Preparation of spinning solution: PVA particles are mixed with deionized water to prepare a spinning solution with a concentration of 10g / 100mL. The solution is mechanically stirred at 80℃ for 8h to ensure that the PVA particles are completely melted. Then, the solution is allowed to stand for 1h to remove bubbles and ensure the quality of fiber forming. S22, Electrospinning process: Control the spinning environment temperature at 25℃ and relative humidity at 30%, set the spinning voltage at 24kV, the feed speed at 0.65ml / h, and the working distance at 18cm; electrospin the spinning solution obtained in step S21 onto the upper surface of the transport layer obtained in step S1 to form a PVA nanofiber layer. S23, Crosslinking treatment: The double-layer fabric-PVA nanofiber layer obtained in step S22 is crosslinked. The PVA nanofiber hydrophilic layer was obtained by immersing the nanofiber in a glutaraldehyde-acetone solution with pH=2 (glutaraldehyde concentration 2g / 100mL) for 1 hour at room temperature, rinsing with plenty of deionized water to remove residual reagents, and drying.

[0035] The PVA nanofibers in the hydrophilic layer have a diameter of 200-300 nm and a porosity of 60-70%.

[0036] Preparation of S3 and PVDF hydrophobic layer: S31. Preparation of spraying solution: Dissolve PVDF powder in a mixed solvent of N,N-dimethylformamide and acetone (weight ratio 7:3) to prepare a spraying solution with a concentration of 8g / 100mL. Stir at room temperature for 10h to ensure that the PVDF powder is completely dissolved. S32, Electrostatic spraying process: control the spraying environment temperature to 28℃ and relative humidity to 30%, set the spraying voltage to 17kV, the advance speed to 1.5ml / h, the working distance to 15cm, and the spraying time to 2h; electrostatically spray the spraying liquid obtained in step S31 onto the lower surface of the transport layer to obtain a PVDF hydrophobic layer.

[0037] The water contact angle of the PVDF hydrophobic layer is 136°.

[0038] Composite fabric product performance: Moisture permeability 3500g / (m²) 2 After cycling at -20℃, the performance retention rate is 90%; after 500 hours of UV aging, the performance retention rate is 88%; and the unit area weight is 1.3 kg / m². 2 Tensile strength 8.2 MPa.

[0039] Example 2 A method for preparing a building waterproof composite fabric with unidirectional moisture-wicking function includes the following steps: Preparation of the transport layer of S1, polyester and cellulose blended nonwoven fabric: S11. Preparation of spunlace nonwoven fabric: The spunlace nonwoven fabric includes polyester fiber and cellulose fiber, and the blending mass ratio of polyester fiber and cellulose fiber is 6:4. S12. Preparation of transport layer: Take a 7g / 100mL hydrophilic finishing agent (polyester polyether) for fabric, add deionized water and stir mechanically for 2h to obtain a finishing agent solution; immerse the blended spunlace nonwoven fabric in the finishing agent solution for 10h, and then dry it in a vacuum oven at 85℃ for 2h to obtain the transport layer.

[0040] The moisture diffusion rate of the transport layer treated by the above process is stable at 0.21 cm / s.

[0041] Preparation of S2 and PVA nanofiber hydrophilic layers: S21. Preparation of spinning solution: PVA particles are mixed with deionized water to prepare a spinning solution with a concentration of 12g / 100mL. The solution is mechanically stirred at 90℃ for 7h to ensure that the PVA particles are completely melted. Then, the solution is allowed to stand for 1h to remove bubbles and ensure the quality of fiber forming. S22, Electrospinning process: Control the spinning environment temperature at 25℃ and relative humidity at 30%, set the spinning voltage at 24kV, the feed speed at 0.65ml / h, and the working distance at 18cm; electrospin the spinning solution obtained in step S21 onto the upper surface of the transport layer obtained in step S1 to form a PVA nanofiber layer. S23, Crosslinking treatment: The double-layer fabric-PVA nanofiber layer obtained in step S22 is crosslinked. The PVA nanofiber hydrophilic layer was obtained by immersing the nanofiber in a glutaraldehyde-acetone solution with pH=2 (glutaraldehyde concentration 2g / 100mL) for 1.5h at room temperature, rinsing with plenty of deionized water to remove residual reagents, and drying.

[0042] The PVA nanofibers in the hydrophilic layer have a diameter of 200-300 nm and a porosity of 60%-70%.

[0043] Preparation of S3 and PVDF hydrophobic layer: S31. Preparation of spraying solution: Dissolve PVDF powder in a mixed solvent of N,N-dimethylformamide and acetone (weight ratio 7:3) to prepare a spraying solution with a concentration of 8g / 100mL. Stir at room temperature for 11h to ensure that the PVDF powder is completely dissolved. S32, Electrostatic spraying process: control the spraying environment temperature to 28℃ and relative humidity to 30%, set the spraying voltage to 17kV, the advance speed to 1.5ml / h, the working distance to 15cm, and the spraying time to 2h; electrostatically spray the spraying liquid obtained in step S31 onto the lower surface of the transport layer to obtain a PVDF hydrophobic layer.

[0044] The water contact angle of the PVDF hydrophobic layer is 138°.

[0045] Composite fabric product performance: Moisture permeability ≥3800g / (m²) 2 After cycling at -20℃, the performance retention rate is 92%; after 500 hours of UV aging, the performance retention rate is 91%; and the weight per unit area is 1.2 kg / m². 2 Tensile strength 8.5 MPa.

[0046] Example 3 A method for preparing a building waterproof composite fabric with unidirectional moisture-wicking function includes the following steps: Preparation of the transport layer of S1, polyester and cellulose blended nonwoven fabric: S11. Preparation of spunlace nonwoven fabric: The spunlace nonwoven fabric includes polyester fiber and cellulose fiber, and the blending mass ratio of polyester fiber and cellulose fiber is 5:5. S12. Preparation of transport layer: Take a 7g / 100mL hydrophilic finishing agent for fabric, add deionized water and stir mechanically for 2h to obtain a finishing agent solution; immerse the blended spunlace nonwoven fabric in the finishing agent solution for 10h, and then dry it in a vacuum oven at 90℃ for 2h to obtain the transport layer.

[0047] The moisture diffusion rate of the transport layer treated by the above process is stable at 0.18 cm / s.

[0048] Preparation of S2 and PVA nanofiber hydrophilic layers: S21. Preparation of spinning solution: PVA particles are mixed with deionized water to prepare a spinning solution with a concentration of 10g / 100mL. The solution is mechanically stirred at 80℃ for 7h to ensure that the PVA particles are completely melted. Then, the solution is allowed to stand for 1h to remove bubbles and ensure the quality of fiber forming. S22, Electrospinning process: Control the spinning environment temperature at 25℃ and relative humidity at 30%, set the spinning voltage at 24kV, the feed speed at 0.65ml / h, and the working distance at 18cm; electrospin the spinning solution obtained in step S21 onto the upper surface of the transport layer obtained in step S1 to form a PVA nanofiber layer. S23, Crosslinking treatment: The double-layer fabric-PVA nanofiber layer obtained in step S22 is crosslinked. The PVA nanofiber hydrophilic layer was obtained by immersing the nanofiber in a glutaraldehyde-acetone solution with pH=2 (glutaraldehyde concentration 2g / 100mL) for 1.5h at room temperature, rinsing with plenty of deionized water to remove residual reagents, and drying.

[0049] The PVA nanofibers in the hydrophilic layer have a diameter of 200-300 nm and a porosity of 60-70%.

[0050] Preparation of S3 and PVDF hydrophobic layer: S31. Preparation of spraying solution: Dissolve PVDF powder in a mixed solvent of N,N-dimethylformamide and acetone (weight ratio 7:3) to prepare a spraying solution with a concentration of 8g / 100mL. Stir at room temperature for 10h to ensure that the PVDF powder is completely dissolved. S32, Electrostatic spraying process: control the spraying environment temperature to 28℃ and relative humidity to 30%, set the spraying voltage to 17kV, the advance speed to 1.5ml / h, the working distance to 15cm, and the spraying time to 2h; electrostatically spray the spraying liquid obtained in step S31 onto the lower surface of the transport layer to obtain a PVDF hydrophobic layer.

[0051] The water contact angle of the PVDF hydrophobic layer is 135°.

[0052] Composite fabric product performance: Moisture permeability ≥3200g / (m 2After cycling at -20℃, the performance retention rate is 89%; after 500 hours of UV aging, the performance retention rate is 89%; and the weight per unit area is 1.25 kg / m². 2 Tensile strength 8.3 MPa.

[0053] Detailed characterization data of the embodiments (taking Embodiment 2 as an example) (1) Scanning electron microscopy (SEM) characterization: Test instrument: SU8010 field emission scanning electron microscope (Hitachi).

[0054] Test conditions: accelerating voltage 5kV, working distance 8mm, gold sputtering treatment (thickness 5nm).

[0055] Characterization results: Transport layer (6:4 blend of polyester and cellulose): The fibers are evenly interwoven with a porosity of 60-70%. The polyester fibers have a diameter of 12-15μm, and the PVA nanofibers have a diameter of 200-300nm. The interwoven parts form continuous moisture-conducting channels to ensure rapid moisture diffusion.

[0056] PVA nanofiber hydrophilic layer: The nanofibers are randomly distributed in a network without agglomeration. The fiber diameter ranges from 200 to 300 nm, with an average diameter of 240 nm (statistical analysis of 300 fibers, standard deviation 3.2 nm). The porosity is 60 to 70% (mercury porosimetry test, instrument: AutoPore IV 9500), which is beneficial for capillary water absorption and moisture wicking.

[0057] PVDF hydrophobic layer: The film is continuous and dense with a micro-nano rough structure on the surface. It has no obvious pore defects, is tightly bonded to the transport layer, and does not peel off, ensuring waterproof performance and structural stability.

[0058] (2) Verification of crosslinking effect by infrared spectroscopy (FT-IR): Test instrument: Nicolet iS50 Fourier transform infrared spectrometer (Thermo Fisher Scientific).

[0059] Test conditions: ATR mode, scanning range 4000~400cm -1 32 scans, 4cm resolution -1 .

[0060] Characterization results: Uncrosslinked PVA fiber: 3342cm -1 The peak at 1095 cm⁻¹ is the -OH stretching vibration peak (strong and broad peak). -1 The peak at this location represents the stretching vibration of COC.

[0061] Cross-linked PVA nanofiber hydrophilic layer: 3342 cm -1The intensity of the -OH peak decreased (absorbance dropped from 1.82 to 1.15), at 1542 cm⁻¹. -1 The appearance of a new characteristic peak (C=N stretching vibration peak) proves that glutaraldehyde undergoes a cross-linking reaction with the PVA molecular chain to form a Schiff base structure, which effectively improves the structural stability and water resistance of the PVA layer.

[0062] (3) Contact angle and waterproof performance characterization: Test instrument: OCA20 contact angle measuring instrument (Dataphysics, Germany).

[0063] Test conditions: 25℃, 30%RH, 5μL deionized water droplet volume, 5 different points were tested for each sample, and the average value was taken.

[0064] Characterization results: PVDF hydrophobic layer: water contact angle 138° (standard deviation 2.1°), roll-off angle ≤15°, meeting the superhydrophobic surface standard; after 50 friction tests (load 500g, friction distance 10cm), the contact angle still remains at 132°, with excellent wear resistance, suitable for outdoor building use scenarios.

[0065] PVA nanofiber hydrophilic layer: water contact angle ≤15°, water droplets spread completely within 1s, moisture absorption rate up to 0.05g / s, strong hydrophilicity ensures rapid adsorption and transport of moisture.

[0066] (4) Dynamic characterization of moisture-wicking performance: Testing instrument: Self-made dynamic moisture transfer tester (GB / T 21655.2-2008).

[0067] The test environment parameters were set to a temperature of 25℃ and an initial relative humidity of 30%, simultaneously simulating a typical humidity environment of 80%RH inside a building, which is consistent with actual application conditions.

[0068] Test results show that the average time for unidirectional water transfer from the PVDF hydrophobic layer to the PVA nanofiber hydrophilic layer is 16 seconds, indicating a fast unidirectional transfer response rate; the cumulative unidirectional transfer amount of the material reaches 12000 g / m³ within 10 minutes. 2 It exhibits excellent unidirectional moisture conduction efficiency; after 24 hours of continuous stability testing, the material's unidirectional transfer performance showed no significant attenuation, demonstrating high efficiency and stability throughout the entire process.

[0069] Each test group has 3 parallel samples, the relative deviation of the test data is ≤2.1%, the experimental data has good repeatability, and the results are reliable.

[0070] Performance verification and synergistic effect (1) Quantitative data on interlayer synergistic moisture conduction: The moisture permeability rate was tested according to GB / T 21655.2-2008 standard. The moisture wicking properties of the single material and the composite fabric of this invention were compared, and the results are shown in Table 1: Table 1. Moisture-wicking performance data of single materials and composite fabrics of the present invention

[0071] As shown in Table 1, the moisture permeability of the composite fabric prepared in Example 2 of the present invention is 1.81 times that of a single PVA layer and 2.24 times that of a single transport layer. The moisture absorption and moisture diffusion efficiency are significantly improved, demonstrating a non-obvious synergistic effect. This effect is due to the synergistic effect of the fast diffusion characteristics of the blended layer and the strong capillary force of the PVA layer.

[0072] (2) Building outdoor environment adaptation verification: Referring to GB / T 18244-2017, the test standard for waterproof membranes for buildings, the composite fabric of Example 2 of this invention was subjected to high and low temperature cycling (-20℃~60℃, 50 cycles) and ultraviolet aging (500h, wavelength 290~400nm, intensity 0.8W / m). 2 The environmental adaptability was tested and verified, and the results are shown in Table 2: Table 2 Environmental adaptability data of composite fabrics in Example 2

[0073] As shown in Table 2, the composite fabric of Example 2 of the present invention maintains stable waterproof performance, moisture wicking performance and hydrophobic layer characteristics under extreme outdoor temperature environment and long-term ultraviolet radiation. The retention rate of each index is ≥90%, which fully meets the long-term outdoor use requirements of buildings.

[0074] (3) Quantitative comparison with existing building waterproofing materials: The core performance of the composite fabric of Example 2 of this invention was quantitatively compared with that of traditional SBS modified bitumen waterproof membrane and fabric in existing patent document (CN119526835B). The results are shown in Table 3: Table 3 Core performance data of composite fabric and traditional SBS modified bitumen waterproof membrane in Example 2

[0075] As shown in Table 3, the composite fabric of Example 2 of the present invention has a 670% higher moisture wicking capacity than the traditional SBS modified bitumen waterproof membrane, a 30% lower unit area weight, an 18% higher tensile strength, and a 15% higher UV aging resistance retention rate. Compared with the fabric in the patent document, the moisture wicking capacity is increased by 87% and the tensile strength is increased by 25%, showing significant comprehensive performance advantages and demonstrating obvious technological progress.

[0076] The embodiments of the present invention have been described in detail above, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A waterproof composite fabric for buildings with unidirectional moisture-wicking function, characterized in that: It includes a composite fabric body, which comprises, from bottom to top, a PVDF hydrophobic layer, a polyester and cellulose blended nonwoven fabric transport layer, and a PVA nanofiber hydrophilic layer.

2. The building waterproof composite fabric with unidirectional moisture-wicking function according to claim 1, characterized in that: In the polyester and cellulose blended nonwoven transport layer, the mass ratio of polyester to cellulose is 5:5 to 7:

3. The transport layer is treated with a fabric hydrophilic finishing agent with a concentration of 5 to 10 g / 100 mL, and the water diffusion rate is 0.18 to 0.21 cm / s. The PVA nanofiber hydrophilic layer has a PVA nanofiber diameter of 200 to 300 nm and a porosity of 60% to 70%, and is cross-linked with glutaraldehyde acetone solution. The PVDF hydrophobic layer has a water contact angle ≥135°, a waterproof rating of IPX7, and a thickness of 20 to 30 μm.

3. The building waterproof composite fabric with unidirectional moisture-wicking function according to claim 2, characterized in that: When the mass ratio of polyester to cellulose is 6:4, the moisture permeability of the composite fabric is ≥3800g / (m³). 2 (·h), after exposure to temperatures ranging from -20℃ to 60℃ and 500 hours of ultraviolet radiation, the retention rate of waterproof and moisture-wicking properties is ≥90%; the unit area weight of the composite fabric is 1.2 kg / m². 2 Tensile strength ≥ 8.5 MPa.

4. A method for preparing a building waterproof composite fabric with unidirectional moisture-wicking function, used to prepare the building waterproof composite fabric with unidirectional moisture-wicking function as described in any one of claims 1 to 3, characterized in that: Includes the following steps: Preparation of the transport layer of S1, polyester and cellulose blended nonwoven fabric: S11. Preparation of spunlace nonwoven fabric: The spunlace nonwoven fabric includes polyester fiber and cellulose fiber, and the blending mass ratio of polyester fiber and cellulose fiber is 5:5~7:

3. S12. Preparation of transport layer: Take a hydrophilic finishing agent for fabric with a concentration of 5~10g / 100mL, add deionized water and stir mechanically for 1~2h to obtain a finishing agent solution; immerse the blended spunlace nonwoven fabric in the finishing agent solution for 6~12h, and then dry it in a vacuum oven at 80~120℃ for 2~3h to obtain the transport layer. Preparation of S2 and PVA nanofiber hydrophilic layers: S21. Preparation of spinning solution: PVA particles are mixed with deionized water to prepare a spinning solution with a concentration of 10~15g / 100mL. The solution is mechanically stirred at 80~95℃ for 6~8h, and then allowed to stand for degassing for 1~2h. S22, Electrospinning process: Control the spinning environment temperature to 25~30℃, relative humidity to 30%~35%, set the spinning voltage to 22~24kV, feed speed to 0.6~0.7ml / h, and working distance to 15~20cm; electrospin the spinning solution obtained in step S21 onto the upper surface of the transport layer obtained in step S1 to form a PVA nanofiber layer. S23. Crosslinking treatment: The PVA nanofiber layer obtained in step S22 is immersed in a glutaraldehyde-acetone solution with pH=2 and crosslinked at room temperature for 1-2 hours. After removal, it is rinsed with deionized water to remove residual reagents and dried to obtain a hydrophilic PVA nanofiber layer. Preparation of S3 and PVDF hydrophobic layer: S31. Preparation of spraying solution: Dissolve PVDF powder in a mixed solvent of N,N-dimethylformamide and acetone to prepare a spraying solution with a concentration of 5~10g / 100mL, and stir at room temperature for 10~12h. S32, Electrostatic spraying process: Control the spraying environment temperature to 25~30℃, relative humidity to 30%~35%, set the spraying voltage to 16~18kV, the advance speed to 1.5ml / h, the working distance to 10~15cm, and the spraying time to 1~4h; electrostatically spray the spraying liquid obtained in step S31 onto the lower surface of the transport layer to obtain a PVDF hydrophobic layer.

5. The method for preparing the building waterproof composite fabric with unidirectional moisture-wicking function according to claim 4, characterized in that: In step S11, the blending mass ratio of polyester fiber and cellulose fiber is 6:4; in step S12, the concentration of the hydrophilic finishing agent for the fabric is 7g / 100mL, and the hydrophilic finishing agent for the fabric is a polyester polyether; the blended spunlace nonwoven fabric is immersed in the finishing agent solution for 10h, and then dried in a vacuum oven at 85℃ for 2h.

6. The method for preparing the building waterproof composite fabric with unidirectional moisture-wicking function according to claim 4, characterized in that: In step S21, PVA particles are mixed with deionized water to prepare a spinning solution with a concentration of 12 g / 100 mL, and mechanically stirred at 90 °C for 7 h; in step S22, the PVA layer porosity is 60-70% when the spinning voltage is 22-24 kV; the feed speed is 0.65 ml / h; and the working distance is 18 cm; in step S23, the glutaraldehyde concentration in the glutaraldehyde-acetone solution is 2 g / 100 mL; and crosslinking is performed at room temperature for 1.5 h.

7. The method for preparing the building waterproof composite fabric with unidirectional moisture-wicking function according to claim 4, characterized in that: In step S31, the weight ratio of N,N-dimethylformamide to acetone is 7:3, and a spraying solution with a concentration of 8g / 100mL is prepared and stirred at room temperature for 11h; in step S32, the spraying voltage is 17kV and the spraying time is 2h.

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