Ultra-permeable waterproof nonwoven fabric based on a multi-layer composite structure and method for producing the same

Abstract

The application provides an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof, and belongs to the non-woven fabric field. PTFE is mixed with a perfluoroalkane solvent, stirred to form a first spinning solution, electrospun to obtain a PTFE microporous membrane; PP particles are melted, blown into PP superfine fibers by high-pressure hot air, deposited to form a fluffy structure, and a PP superfine fiber layer is obtained; HDPE is dissolved in xylene to obtain a second spinning solution, and the HDPE is burst into PE superfine fibers by a flash evaporation process, and a uniform microporous layer is formed by deposition to obtain a PE superfine fiber layer; the PTFE microporous membrane, the PP superfine fiber layer and the PE superfine fiber layer are stacked from outside to inside in sequence, and hot-pressing is performed to obtain the ultra-permeable waterproof non-woven fabric based on the multi-layer composite structure. The application significantly improves the comprehensive performance of the non-woven fabric through the glue-free hot-pressing process and the collaborative design of the multi-layer material.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-woven fabrics, in particular to an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof. BACKGROUND

[0002] In recent years, non-woven fabrics have been widely used in medical protection, sanitary products and packaging due to their light weight, high air permeability and low cost characteristics. However, the existing technology always faces the core contradiction that air permeability, waterproofness and mechanical strength are difficult to be optimized simultaneously. Although traditional single-layer melt-blown non-woven fabrics (such as polypropylene PP) have basic air permeability (30-50 L / (m 2 ·s), their waterproof performance is insufficient (hydrostatic pressure ≤5kPa), and their mechanical strength is low (tensile strength ≤20MPa), which is difficult to meet the needs of high protection scenarios. In order to improve waterproofness, some studies have proposed a double-layer composite structure (PP melt-blown layer + PE film) combined with hot melt adhesive bonding technology to increase the hydrostatic pressure to 10kPa. However, the introduction of the adhesive causes pore blockage, and the air permeability drops to below 40 L / (m 2 ·s), and the aging problem of the adhesive layer significantly reduces the interlayer peeling strength (≤0.8N / cm), which is prone to delamination failure during long-term use. On the other hand, polyethylene (PE) non-woven fabrics prepared by flash evaporation can achieve high air permeability through micro-porous structure design, but due to the insufficient strength of a single material and the lack of an effective waterproof layer, the hydrostatic pressure is only 3kPa, which cannot meet the liquid barrier requirements.

[0003] Therefore, it is necessary to design an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof to solve the above problems. SUMMARY

[0004] In view of the technical problems in the background art, the present application provides an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof, aiming to solve the technical problem that traditional non-woven fabrics cannot simultaneously consider air permeability, waterproofness and mechanical strength.

[0005] In a first aspect, the present application provides a preparation method of an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure, comprising the following steps:

[0006] S1. mixing PTFE with perfluoroalkane solvent, stirring to form a first spinning solution, and obtaining a PTFE microporous membrane through electrospinning;

[0007] S2. melting PP particles, blowing them into PP ultra-fine fibers through high-pressure hot air, and obtaining a PP ultra-fine fiber layer by depositing the PP ultra-fine fibers into a fluffy structure;

[0008] S3. dissolving HDPE in xylene to obtain a second spinning solution, and making HDPE burst into PE superfine fibers through a flash process to form a uniform microporous layer, thereby obtaining a PE superfine fiber layer;

[0009] S4. sequentially stacking the PTFE microporous membrane, the PP superfine fiber layer and the PE superfine fiber layer from outside to inside, and obtaining an ultra gas permeable waterproof non-woven fabric based on a multi-layer composite structure through hot pressing.

[0010] As a further improvement of the present application, the content of PTFE in the first spinning solution is 8-14wt% in step S1.

[0011] As a further improvement of the present application, the voltage of electrospinning is 20-25kV, the receiving distance is 15-20cm, and the ambient humidity is ≤40%.

[0012] As a further improvement of the present application, the thickness of the PTFE microporous membrane is 45-55μm, the pore size is 1-5μm, and the fiber diameter is 0.5-2μm.

[0013] As a further improvement of the present application, the temperature of melting is 235-245℃, the pressure of high-pressure hot air is 0.6-0.8MPa, and the temperature is 250-280℃ in step S2.

[0014] As a further improvement of the present application, the diameter of the PP superfine fiber is 5-10μm, and the porosity of the PP superfine fiber layer is ≥80%.

[0015] As a further improvement of the present application, the content of HDPE in the second spinning solution is 8-10wt% in step S3.

[0016] As a further improvement of the present application, the temperature of the flash process is 80-85℃, and the diameter of the PE superfine fiber is 0.5-1μm.

[0017] As a further improvement of the present application, the temperature of hot pressing is 125-135℃, the pressure is 0.4-0.6MPa, and the time is 5-10s in step S4.

[0018] In a second aspect, the present application provides an ultra gas permeable waterproof non-woven fabric based on a multi-layer composite structure, which is prepared by the preparation method of the first aspect, and the interlayer peeling strength of the ultra gas permeable waterproof non-woven fabric based on a multi-layer composite structure is ≥1.5N / cm.

[0019] The present application has the following beneficial effects:

[0020] The application provides an ultra-breathable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof, and the PTFE is mixed with a perfluoroalkane solvent to form a first spinning solution through stirring, and a PTFE microporous membrane is obtained through electrospinning; PP particles are melted to be blown into PP superfine fibers through high-pressure hot air, and a fluffy structure is formed through deposition to obtain a PP superfine fiber layer; HDPE is dissolved in xylene to obtain a second spinning solution, and the HDPE is burst into PE superfine fibers through a flash evaporation process to form a uniform microporous layer through deposition to obtain a PE superfine fiber layer; the PTFE microporous membrane, the PP superfine fiber layer and the PE superfine fiber layer are stacked from outside to inside in sequence, and an ultra-breathable waterproof non-woven fabric based on a multi-layer composite structure is obtained through hot pressing and compounding. The application solves the problem that the air permeability, waterproofness and strength of the traditional non-woven fabric are difficult to coordinate through the glue-free hot pressing and compounding process and the collaborative design of the multi-layer material, and the comprehensive performance of the non-woven fabric is significantly improved under the premise of ensuring environmental protection.

[0021] The application discards the traditional adhesive compounding process, adopts a three-layer structure of PTFE microporous membrane (waterproof layer) + PP superfine fiber layer (reinforcing layer) + PE superfine fiber layer (breathable layer), and realizes high-strength combination (peeling strength ≥ 1.5 N / cm) between layers through glue-free hot pressing and compounding technology. The PTFE membrane forms a selective breathable channel by adjusting the pore size through the electrospinning process; the PP layer provides mechanical support to make up for the strength defects of the PE layer; the PE layer optimizes the pore size distribution (standard deviation < 0.3 μm) to ensure the gas permeation efficiency. The design not only avoids the pollution risk of chemical adhesives, but also can flexibly adapt to different application scene requirements by adjusting process parameters (such as hot pressing temperature and pressure), and shows significant technical advantages in the fields of medical protection and outdoor equipment.

[0022] The above description is only a summary of the technical solutions of the application, in order to more clearly understand the technical means of the application, the specific embodiments of the application can be implemented according to the content of the specification, and in order to make the above and other purposes, characteristics and advantages of the application more obvious and easy to understand, the following will specifically describe the embodiments of the application. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the application, the drawings used in the application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0024] Figure 1 The preparation method flow chart of the ultra-breathable waterproof non-woven fabric based on a multi-layer composite structure provided by the embodiments of the application is shown in the figure;

[0025] Figure 2A structure diagram of the super-breathable waterproof non-woven fabric based on the multi-layer composite structure provided in the embodiment of the present application is shown in the figure;

[0026] Figure 3 A physical diagram of the PP superfine fiber layer provided in the embodiment 1 of the present application is shown in the figure;

[0027] Figure 4 A physical diagram of the super-breathable waterproof non-woven fabric based on the multi-layer composite structure provided in the embodiment 1 of the present application is shown in the figure;

[0028] The figure legend is as follows: 1, PTFE microporous membrane; 2, PP superfine fiber layer; 3, PE superfine fiber layer. DETAILED DESCRIPTION

[0029] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above figure description, are intended to cover non-exclusive inclusion.

[0031] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0032] In this paper, the reference to "embodiments" means that the specific features, structures or properties described in conjunction with the embodiments can be included in at least one embodiment of the present application. The appearance of this phrase in various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. The skilled person in the art explicitly and implicitly understands that the embodiments described herein can be combined with other embodiments.

[0033] Traditional single-layer melt-blown non-woven fabric has good air permeability, but poor waterproofness and strength; double-layer composite structure improves waterproofness, but sacrifices air permeability, and has aging problem of adhesive layer; flash-evaporation PE non-woven fabric has high air permeability, but poor strength and waterproofness; and hot melt adhesive bonding will cause pore blockage, reduce air permeability, and the adhesive layer is easy to age, affecting interlayer peeling strength and long-term performance. In addition, a single material (such as PP or PE) is difficult to simultaneously achieve high air permeability, high waterproofness and high strength.

[0034] In order to solve the technical problem that the traditional non-woven fabric is difficult to balance air permeability, waterproofness and mechanical strength, the application provides an ultra-air-permeable waterproof non-woven fabric based on a multi-layer composite structure and a preparation method thereof, wherein a three-layer structure of PTFE microporous membrane (waterproof layer) + PP ultra-fine fiber layer (reinforcing layer) + PE ultra-fine fiber layer (air permeable layer) is adopted, and high-strength bonding between layers is realized through adhesive-free hot pressing composite technology, solving the problem that the air permeability, waterproofness and strength of traditional non-woven fabric are difficult to coordinate. On the premise of ensuring environmental protection, the comprehensive performance of the non-woven fabric is significantly improved.

[0035] Please refer to Figures 1 to 2 , in a first aspect, the application provides a preparation method of an ultra-air-permeable waterproof non-woven fabric based on a multi-layer composite structure, comprising the following steps:

[0036] S1. Mix PTFE (polytetrafluoroethylene) with perfluoroalkane solvent, stir to form a first spinning solution, and obtain a PTFE microporous membrane 1 through electrospinning;

[0037] S2. Melt PP (polypropylene) particles, blow them into PP ultra-fine fibers through high-pressure hot air, and form a fluffy structure through deposition to obtain a PP ultra-fine fiber layer 2;

[0038] S3. Dissolve HDPE (high-density polyethylene) in xylene to obtain a second spinning solution, and make HDPE burst into PE ultra-fine fibers through flash evaporation process to form a uniform microporous layer through deposition to obtain a PE ultra-fine fiber layer 3;

[0039] S4. Stack the PTFE microporous membrane 1, the PP ultra-fine fiber layer 2 and the PE ultra-fine fiber layer 3 from outside to inside, and obtain an ultra-air-permeable waterproof non-woven fabric based on a multi-layer composite structure through hot pressing.

[0040] In the technical scheme of the embodiment of the present application, the PTFE microporous membrane 1 provides excellent waterproofness and air permeability. The PTFE material has extremely strong hydrophobicity, and the microporous structure thereof can effectively block the passage of liquid while allowing the passage of gas molecules, thereby achieving high air permeability and high waterproofness. The perfluoroalkane solvent can be one of perfluoroheptane, perfluorohexane and perfluoropentane. The PP superfine fiber layer 2 provides a good fluffy structure and mechanical strength. The three-dimensional network structure formed thereby not only enhances the overall mechanical strength and tensile resistance, but also provides a certain buffering property due to the fluffy structure. The PE superfine fiber layer 3 provides a uniform microporous structure and additional waterproofness, further refines the pore structure, and ensures the air permeability of the overall structure.

[0041] The present application adopts a hot-pressing compounding process, does not need to use a chemical adhesive, avoids problems such as pore blockage, air permeability reduction and aging delamination caused by the adhesive, improves the safety and environmental protection of the product, and meets the requirements of different application scenarios by adjusting parameters such as the thickness, pore size and fiber diameter of each layer, and is suitable for fields such as medical protection, sanitary products, outdoor equipment and food packaging.

[0042] Further, in some embodiments, in step S1, the content of PTFE in the first spinning solution is 8-14wt%.

[0043] In the technical scheme of the embodiment of the present application, the content of PTFE affects the viscosity of the spinning solution. If the content is too low, the viscosity of the spinning solution is too small, a stable jet cannot be formed, and the electrospinning process is difficult to perform. If the content is too high, the viscosity of the spinning solution is too large, the jet is difficult to stretch, the fiber diameter will be thick, and the micro-porous structure of the final product will be affected. A suitable PTFE content helps to form a microporous membrane with a suitable pore size and porosity, thereby ensuring high air permeability while also having good waterproofness.

[0044] Further, in some embodiments, the voltage of electrospinning is 20-25kV, the receiving distance is 15-20cm, and the environmental humidity is ≤40%.

[0045] In the technical scheme of the embodiment of the present application, within a suitable voltage range, the electric field strength is high enough to effectively stretch the polymer solution and form fine fibers. However, if the voltage is too high, the fibers may have a beaded structure or discontinuous short fibers, or even cause electrical sparks and damage the equipment. The receiving distance can provide sufficient stretching space while ensuring the continuity and uniformity of the fibers. In a low humidity condition, abnormal fiber morphology such as beaded structure or fiber breakage can be effectively avoided. By adjusting the voltage and solvent concentration, a balance between high hydrostatic pressure and air permeability is achieved, and the hydrophobic property brought by the perfluoroalkane modification can effectively block liquid penetration.

[0046] Further, in some embodiments, the PTFE microporous membrane has a thickness of 45-55 μm, a pore size of 1-5 μm, and a fiber diameter of 0.5-2 μm.

[0047] In the technical solution of the embodiments of the present application, by precisely controlling the film thickness and the pore size, high air permeability and high waterproofness can be achieved. The fiber diameter is 0.5-2 μm, and the network structure formed thereby has good mechanical properties.

[0048] Further, in some embodiments, the melting temperature is 235-245℃, the pressure of the high-pressure hot air is 0.6-0.8 MPa, and the temperature of the high-pressure hot air is 250-280℃.

[0049] In the technical solution of the embodiments of the present application, a higher melting temperature helps the PP particles to completely melt, forming a uniform melt, reducing the viscosity of the melt, and making it easier to form a filament through the nozzle and rapidly cool and solidify under the action of high-pressure hot air to form ultra-fine fibers. By controlling the pressure and temperature of the high-pressure hot air, rapid cooling of the melt and uniform stretching of the fibers are achieved. A melt temperature lower than 230℃ will cause the fiber diameter to increase to 15 μm, and the grammage to exceed the standard (>35 g / m 2 ), and insufficient air flow velocity (<0.6 MPa) will cause the fibers to accumulate.

[0050] Further, in some embodiments, the PP ultra-fine fiber has a diameter of 5-10 μm, and the PP ultra-fine fiber layer 2 has a porosity of ≥80%.

[0051] In the technical solution of the embodiments of the present application, the PP ultra-fine fiber has a small diameter and a large surface area, which is conducive to the rapid passage of gas and liquid. The high porosity further enhances the air permeability, making it perform well in the fields of filtration and protection.

[0052] Further, in some embodiments, in step S3, the content of HDPE in the second spinning solution is 8-10 wt%.

[0053] In the technical solution of the embodiments of the present application, a suitable content of HDPE can optimize the rheological properties of the spinning solution, ensuring good spinnability and uniformity during fiber formation. Too low a content of HDPE may not be able to provide sufficient mechanical strength, while too high a content may result in too large a viscosity of the spinning solution, affecting the precise control of the fiber diameter.

[0054] Further, in some embodiments, the temperature of the flash process is 80-85℃, and the diameter of the PE ultra-fine fiber is 0.5-1 μm.

[0055] In the technical scheme of the embodiment of the present application, the core of the HDPE forming ultra-fine fibers is the physical form change driven by pressure drop and rapid solvent evaporation. The appropriate flash evaporation temperature helps the rapid evaporation of the solvent and the rapid solidification of the polymer, so as to prepare PE ultra-fine fibers with a diameter of 0.5-1 μm; the evaporation temperature > 90℃ will cause fiber thermal degradation (tensile strength < 20 MPa); and the supporting condensing device can recycle more than 95% of the solvent; this step realizes the high-efficiency air permeation function of the air permeation amount ≥ 80 L / (m 2 ·s) by precisely controlling the solvent evaporation and fiber formation.

[0056] Further, in some embodiments, in step S4, the temperature of the hot-pressing composite is 125-135℃, the pressure is 0.4-0.6 MPa, and the time is 5-10 s.

[0057] In the technical scheme of the embodiment of the present application, the PTFE microporous membrane 1, the PP ultra-fine fiber layer 2 and the PE ultra-fine fiber layer 3 are sequentially stacked and then hot-pressed by a double-roller hot press. In the hot-pressing process, the PP ultra-fine fiber layer 2 is partially melted and penetrates into the interface between the PTFE microporous membrane 1 and the PE ultra-fine fiber layer 3, forming a mechanical anchoring structure, so as to firmly combine the three layers of materials together. This process does not need to use adhesive, avoiding the negative effects brought by the adhesive, while ensuring the bonding strength between the layers. The multi-layer composite structure realizes the synergistic optimization of air permeability, waterproofness and mechanical strength through the complementary advantages of different materials. The hot-pressing temperature lower than 120℃ or the time > 15 s respectively leads to the peeling strength < 1.0 N / cm and the PE microporous collapse.

[0058] In a second aspect, the embodiment of the present application provides an ultra-air-permeable waterproof non-woven fabric based on a multi-layer composite structure, which is prepared by the preparation method of the first aspect. The interlayer peeling strength of the non-woven fabric is ≥ 1.5 N / cm.

[0059] The PTFE microporous membrane 1 of the outer layer is prepared by an electrospinning process and has a pore size of 1-5 μm; the PP ultra-fine fiber layer 2 of the middle layer has a grammage of 20-30 g / m 2 and a porosity ≥ 80%; the PE ultra-fine fiber layer 3 of the inner layer has a grammage of 10-15 g / m 2 and a pore size distribution standard deviation < 0.3 μm; the three-layer structure is bonded by a glue-free hot-pressing composite process, and the interlayer peeling strength is ≥ 1.5 N / cm, which ensures the close combination between the layers and improves the overall mechanical strength and durability.

[0060] Some specific examples are listed below. It should be noted that the examples described below are exemplary and are intended to explain the present application only and are not to be construed as limiting the present application. The technical or conditions not specified in the examples are carried out according to the techniques or conditions described in the literature in the art or according to the product instructions. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained by purchase.

[0061] Example 1

[0062] The present embodiment provides a preparation method of an ultra-breathable waterproof non-woven fabric based on a multi-layer composite structure, comprising the following steps:

[0063] S1. Mix PTFE powder with perfluoropentane (C5F 12 ) to form a homogeneous spinning solution, with the content of PTFE being 11wt%, stirring at 80℃ for 2 hours. Extrude from the nozzle (inner diameter 0.5mm) at a rate of 0.5mL / min through a high-voltage electrospinning machine (voltage 22kV), with the receiving device being an aluminum foil coated drum (rotation speed 650rpm) at a receiving distance of 18cm, and the environmental humidity being ≤35%. After the solvent volatilization, a PTFE microporous membrane 1 with fiber diameter of 0.8~1.5μm is formed, with the thickness being 50μm and the average pore size being 2μm (pore size distribution standard deviation 0.4μm);

[0064] S2. Add PP granules into a twin-screw extruder, heat to 238℃ to melt (melt flow rate MFR=40g / 10min), and after extruding through the die slit (width 0.3mm), blow the melt into ultra-fine fibers with diameter of 6~8μm by 0.75MPa high-pressure hot air (260℃), and randomly deposit to form a PP ultra-fine fiber layer 2 with grammage of 25g / m 2 , as shown in the actual object diagram of Figure 3 ;

[0065] S3. Dissolve HDPE in xylene to obtain a second spinning solution, with the concentration of HDPE being 9wt%, stirring at 120℃ until completely dissolved, and then delivered to the flash chamber (temperature 83℃) through a high-pressure pump (pressure 1.1MPa). After the solvent evaporation, the HDPE bursts into ultra-fine fibers with diameter of 0.6~0.9μm, and deposited into a PE ultra-fine fiber layer 3 with grammage of 12g / m 2 (thickness 50μm). The xylene solvent is recovered through a condensing device, with the recovery rate being 96%.

[0066] S4. The PTFE microporous membrane 1, the PP ultra-fine fiber layer 2, and the PE ultra-fine fiber layer 3 are sequentially stacked from the outside to the inside, and are preliminarily fixed by a pre-pressing roller (pressure 0.1 MPa). Subsequently, the PTFE microporous membrane 1, the PP ultra-fine fiber layer 2, and the PE ultra-fine fiber layer 3 are fed into a double-roller hot press (roller temperature 130°C, pressure 0.5 MPa, and residence time 8s), to obtain a super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure. After cooling, the interlayer peeling strength is 1.9 N / cm. The actual photograph is shown in FIG. 5. Figure 4

[0067] The performance of the composite membrane is tested according to the GB / T standard: gas permeability 85 L / (m 2 ·s) (GB / T 5453); hydrostatic pressure 13 kPa (GB / T 4744); longitudinal tensile strength 38 MPa and transverse tensile strength 31 MPa (GB / T 3923.1). The qualified products are cut into 1.2 m wide rolls by a constant tension winding machine (tension 18 N, speed 4 m / min), and are stored in a dry environment with a humidity of ≤30%.

[0068] In this embodiment, the super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure is successfully prepared by precise parameter matching and glue-free hot pressing process innovation, and has high gas permeability, excellent waterproofness, and mechanical strength. The performance indicators of the super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure are superior to those of the prior art, as shown in Table 1. The solvent recovery rate (96%) and VOC (volatile organic compound) emission characteristics in the process meet the green manufacturing trend, and are suitable for high-end medical protection and outdoor equipment fields.

[0069] Example 2

[0070] In this embodiment, a preparation method of a super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure is provided. Compared with Example 1, the only difference is that the electrospinning voltage of the PTFE microporous membrane 1 is 25 kV, the average pore size is reduced to 1 μm, and the hot pressing temperature is increased to 135°C and the residence time is shortened to 6s, so as to strengthen the interface bonding efficiency.

[0071] Example 3

[0072] In this embodiment, a preparation method of a super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure is provided. Compared with Example 1, the only difference is that the PP melt blowing temperature is increased to 245°C, and the hot pressing time is shortened to 5s.

[0073] Example 4

[0074] In this embodiment, a preparation method of a super gas-permeable waterproof non-woven fabric based on a multi-layer composite structure is provided. Compared with Example 1, the only difference is that the content of PTFE in the PTFE spinning solution is 8 wt%.

[0075] Example 5

[0076] ​The embodiment provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the content of PTFE in the PTFE spinning solution is 14 wt%.

[0077] Comparative example 1

[0078] The comparative example 1 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that a traditional adhesive composite process is adopted, the glue hot pressing step is completely omitted, and a polyurethane adhesive (coating amount 10 g / m 2 ) is used to bond the PTFE microporous membrane 1, the PE superfine fiber layer 2 and the PP superfine fiber layer 3.

[0079] Comparative example 2

[0080] The comparative example 2 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the preparation and composite steps of the PTFE microporous membrane and the PE superfine fiber layer are cancelled, and only a single PP superfine fiber layer (gram weight 30 g / m 2 ) is reserved.

[0081] Comparative example 3

[0082] The comparative example 3 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the content of PTFE in the PTFE spinning solution is 6 wt%.

[0083] Comparative example 4

[0084] The comparative example 4 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the content of PTFE in the PTFE spinning solution is 16 wt%.

[0085] Comparative example 5

[0086] The comparative example 5 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the pressure of the high-pressure hot air is 0.5 MPa.

[0087] Comparative example 6

[0088] The comparative example 6 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the PP melting temperature is 230 DEG C.

[0089] Comparative example 7

[0090] The comparative example 7 provides a preparation method of the super-breathable waterproof non-woven fabric based on a multilayer composite structure, and only differs from the embodiment 1 in that the flash-off temperature is 90 DEG C.

[0091] Comparative Example 8

[0092] Comparative Example 8 provides a preparation method of the super-breathable waterproof non-woven fabric based on the multi-layer composite structure, compared with Example 1, the only difference is that the hot-pressing temperature is 110℃.

[0093] Comparative Example 9

[0094] Comparative Example 9 provides a preparation method of the super-breathable waterproof non-woven fabric based on the multi-layer composite structure, compared with Example 1, the only difference is that the hot-pressing time is 15s.

[0095] Table 1 Comprehensive Performance Comparison

[0096]

[0097] From Table 1, it can be seen that the present application realizes balanced optimization in air permeability, peel strength, tensile strength and hydrostatic pressure through the glue-free hot-pressing process and the PTFE nanofiber reinforcement technology, and is environmentally friendly and pollution-free. Comparative Example 1 has poor pollution performance due to the adhesive, and Comparative Examples 2-9 have significantly reduced comprehensive performance due to the imbalance of single material and process or the out-of-control key parameters.

[0098] It should be noted that the present application is not limited to the above-mentioned embodiments. The above-mentioned embodiments are only examples, and embodiments having the same technical idea and playing the same role and effect within the scope of the technical solutions of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for preparing a super gas permeable waterproof nonwoven fabric based on a multilayer composite structure, characterized by, The method comprises the following steps: S1. mixing PTFE with a perfluoroalkane solvent, stirring to form a first spinning solution, electrospinning to obtain a PTFE microporous membrane; the content of PTFE in the first spinning solution is 8-14wt%; S2. melting PP particles, blowing into PP ultrafine fibers by high-pressure hot air, depositing to form a fluffy structure to obtain a PP ultrafine fiber layer; S3. dissolving HDPE in xylene to obtain a second spinning solution, making HDPE burst into PE ultrafine fibers by a flash process, depositing to form a uniform microporous layer to obtain a PE ultrafine fiber layer; the content of HDPE in the second spinning solution is 8-10wt%; the temperature of the flash process is 80-85℃; S4. stacking the PTFE microporous membrane, the PP ultrafine fiber layer and the PE ultrafine fiber layer from outside to inside in turn, hot pressing to obtain an ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure.

2. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, In step S1, the voltage of the electrospinning is 20-25kV, the receiving distance is 15-20cm, and the environmental humidity is ≤40%.

3. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, The thickness of the PTFE microporous membrane is 45-55μm, the pore size is 1-5μm, and the fiber diameter is 0.5-2μm.

4. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, In step S2, the melting temperature is 235-245℃, the pressure of the high-pressure hot air is 0.6-0.8MPa, and the temperature is 250-280℃.

5. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, The diameter of the PP ultrafine fiber is 5-10μm, and the porosity of the PP ultrafine fiber layer is ≥80%.

6. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, The diameter of the PE ultrafine fiber is 0.5-1μm.

7. The method for preparing ultra-breathable and waterproof nonwoven fabric based on a multi-layer composite structure according to claim 1, characterized in that, In step S4, the hot pressing temperature is 125-135℃, the pressure is 0.4-0.6MPa, and the time is 5-10s.

8. A super gas permeable waterproof nonwoven fabric based on a multilayer composite structure, characterized by, The interlayer peeling strength of the ultra-permeable waterproof non-woven fabric based on a multi-layer composite structure prepared by the method of any one of claims 1-7 is ≥1.5N / cm.

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