A water repellent nylon fabric and a method for making the same

Abstract

The application discloses a water-repellent nylon fabric and a preparation method thereof. The preparation method is as follows: nylon 6 chips and a water-repellent agent are used as raw materials, blended, extruded and granulated to obtain a nylon water-repellent master batch; nylon 6 chips, boron nitride and calcium carbonate are used as raw materials, blended, extruded and granulated to obtain a nylon microporous master batch; the nylon water-repellent master batch and the nylon chips are used as core layer raw materials, and the nylon microporous master batch is used as a skin layer raw material; after forming by using a skin-core composite spinning process, the fiber skin layer is treated in a weak acid bath to form micropores, and then the fiber is treated in a weak alkali bath, a water bath, dried, woven into a fabric and heat set to make the water-repellent agent in the fiber core layer migrate to the fiber surface through the micropores. The preparation method ensures normal oiling of the fiber, improves spinnability, and does not affect the fiber mechanics, and meanwhile, the water-repellent agent can uniformly migrate to the fiber surface through the micro-nano structure formed on the fiber surface after acid treatment, so that the fabric is endowed with durable water-repellent effect.

Description

Technical Field

[0001] This invention relates to a water-repellent nylon fabric and its preparation method, belonging to the field of functional fiber technology. Background Technology

[0002] Nylon fiber (also known as polyamide fiber, commonly called nylon) is a common synthetic fiber. Nylon boasts the best abrasion resistance among all natural and synthetic fibers, exceeding cotton by 10 times and wool by 20 times, far surpassing other synthetic fibers such as polyester. Furthermore, the fiber has high breaking strength, minimally affected by humidity (wet strength is only about 10% lower than dry strength), resulting in fabrics with strong tensile and impact resistance, making them less prone to damage. It also exhibits high elastic recovery, easily restoring its original shape after deformation, with good wrinkle resistance and shape retention. Simultaneously, the fiber's specific gravity is approximately 1.14, lighter than cotton (1.54) and wool (1.32), making fabrics lighter and less bulky to wear or carry. Therefore, nylon is widely used in outdoor sports equipment; for example, sportswear and athletic shoes often contain nylon fibers. In order to adapt to complex outdoor environments and ensure safety and comfort during sports activities, nylon fibers need to have water-repellent properties. By reducing water absorption and maintaining dryness, they indirectly achieve the key functions of "lightweight reduction, heat loss prevention, and performance protection," which are irreplaceable functional requirements in outdoor scenarios.

[0003] There are four main methods for improving the water-repellent properties of nylon. The first method involves applying a waterproofing agent to the surface of the fabric during finishing processes, forming a thin waterproof film that achieves good water repellency. However, this waterproof film not only covers the fiber surface but also clogs the gaps between the yarns, reducing the fabric's breathability and moisture permeability. This not only affects wearing comfort but also makes it difficult to maintain the waterproof effect after washing. Patent CN109440476B employs this method, utilizing the synergistic effect of polydimethylsiloxane, polyurethane, and polyacrylate to coat the fabric surface, effectively reducing the fabric's surface tension and achieving water repellency. However, this sacrifices the fabric's breathability and washability.

[0004] The second method involves coating the fabric surface. However, water-repellent textiles produced using this process have poor breathability, easily causing a stuffy feeling and affecting wearing comfort. Patent CN103625078A uses this method, achieving waterproofing by adding a composite structure of nano-silver ion powder and PTFE membrane to the fabric. However, fabrics produced by this method have relatively weak moisture absorption, and when worn, sweat can cause the clothing to stick to the skin, resulting in a sticky and uncomfortable feeling.

[0005] The third method involves directly imparting water-repellent properties during the fiber processing stage. Patent CN106283608A proposes replacing traditional spinning oils with a water-repellent treatment liquid in the conventional spinning process for the preparation of polyester fibers. While this method improves the breathability of textiles to some extent, it still falls short in enhancing the fabric's hand feel and functional durability.

[0006] The fourth method involves adding water-repellent components to the fiber in the form of masterbatch during melt spinning. This method produces fibers with better hand feel and longer-lasting functionality. For example, patent CN116970274A describes a water-repellent nylon 6 fiber prepared via masterbatch melt blending, which maintains the original hand feel of nylon 6 while imparting durable water-repellent properties to textiles woven from it. Compared to post-coating methods, textiles woven from fibers prepared using this method have better breathability. Compared to post-coating methods, textiles woven from this invention have advantages in washability and breathability. Compared to existing liquid spinning methods, this invention offers advantages in washability and longer-lasting water repellency. However, this method has a significant drawback: adding water-repellent components during fiber cooling and forming can lead to insufficient oiling during spinning, affecting fiber spinnability and reducing its mechanical properties. Summary of the Invention

[0007] The purpose of this invention is to provide a water-repellent nylon fabric and its preparation method. This preparation method ensures normal oiling of the fibers, improves spinnability, and does not affect the mechanical properties of the fibers. At the same time, it can also form micro-nano structures on the fiber surface during subsequent processing. During heat setting, the water-repellent agent can be uniformly migrated to the fiber surface through the micro-nano structure, thereby giving the fabric a long-lasting water-repellent effect without affecting the breathability of the fibers.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] A method for preparing a water-repellent nylon fabric involves using nylon 6 chips and a water-repellent agent as raw materials, blending them, and then extruding and granulating them to obtain nylon water-repellent masterbatch. Another method involves using nylon 6 chips, boron nitride, and calcium carbonate as raw materials, blending them, and then extruding and granulating them to obtain nylon microporous masterbatch. The nylon water-repellent masterbatch and nylon chips are then used as core layer raw materials, and the nylon microporous masterbatch is used as sheath layer raw material. After forming the fabric using a core-sheath composite spinning process, the fabric is treated with a weak acid bath to form micropores in the fiber sheath layer. It is then dried after a weak alkali bath and a water bath, woven, and heat-set to obtain the fabric, allowing the water-repellent agent in the fiber core layer to migrate to the fiber surface through the micropores.

[0010] Preferably, the resulting fiber has a breaking strength of 3.70~3.75cN / tex, the number of micropores per unit area on the fiber surface is 80~120, the micropore size deviation is no more than 10%, and the unit area refers to 2μm×2μm.

[0011] Preferably, the cross-section of the obtained fiber is: the core layer is "circular" and the sheath layer is "circular", "trilobal", "cross" or "pentalobal".

[0012] Preferably, the preparation method of nylon water-repellent masterbatch is as follows: 5-15 parts by mass of water-repellent agent and 85-95 parts by mass of nylon 6 chips are blended and then melt-extruded and granulated at an extrusion temperature of 240-270℃.

[0013] Preferably, the water-repellent agent is at least one of amino, carboxyl, alcohol, or ester-modified polysiloxanes.

[0014] Preferably, the preparation method of nylon microporous masterbatch is as follows: 5-10 parts by mass of boron nitride, 5-15 parts by mass of calcium carbonate, 0-3 parts by mass of dispersant and 72-90 parts by mass of nylon chips are blended and then melt-extruded and granulated at an extrusion temperature of 240-270℃.

[0015] Preferably, the dispersant is at least one of ethylene bis-stearamide, ethylene-acrylic acid copolymer, and zinc salt ionomer of ethylene-acrylic acid copolymer.

[0016] Preferably, the core layer material comprises, by mass, 5-20 parts of nylon water-repellent masterbatch and 80-95 parts of nylon 6 chips; and the mass ratio of the core layer material to the sheath material is (60-80):(20-40).

[0017] Preferably, the core-sheath composite spinning process parameters are: spinning temperature 250-265℃, spinning speed 4500-6000m / min, side blowing temperature 15-25℃, side blowing speed 0.3-0.8m / s, and oiling rate 0.6-1.2%.

[0018] Preferably, the acid bath is an acetic acid bath, a citric acid bath, or a formic acid bath, with a pH of 5-7, a temperature of 30-50℃, and a duration of 10-30 seconds;

[0019] The weak alkaline bath is an ammonia bath, a sodium bicarbonate bath, or a triethanolamine bath, with a pH of 7-9, a temperature of 30-50℃, and a duration of 10-30 seconds.

[0020] The water bath temperature is 30-50℃, and the duration is 60-120 seconds.

[0021] Preferably, the heat setting conditions are: 180-195℃, 30-50s, and overfeed 1-5%.

[0022] A water-repellent nylon fabric, prepared by any of the methods described above. The fabric has the following warp and weft densities: warp density 100-150 threads / inch, weft density 80-120 threads / inch; water repellency rating 4-5, hydrostatic pressure rating 4-5.

[0023] The beneficial effects of this invention are as follows:

[0024] The water-repellent fiber is not produced through conventional single-component spinning, but rather through composite spinning. The core layer has a circular cross-section, containing conventional nylon 6 chips and water-repellent masterbatch. Without weak acid treatment, micropores do not appear on the sheath surface, preventing the water-repellent components from migrating to the fiber surface during spinning and affecting oiling, thus ensuring the fiber's spinnability and mechanical properties. The sheath layer has a circular or irregular cross-section, containing microporous masterbatch. The microporous masterbatch contains calcium carbonate and boron nitride. Boron nitride provides thermal conductivity, improving pore uniformity; calcium carbonate can be dissolved by acid, which can be used to create micropores and form micro / nano structures on the sheath fiber surface, enhancing the hydrophobic effect. This nylon 6 fiber undergoes a subsequent weak acid treatment. The weak acid reacts with the large amount of calcium carbonate on the fiber surface, leaving micropores and forming a micro / nano structure. Then, the fabric undergoes heat setting, causing the water-repellent agent in the core layer to migrate from the pores to the fiber surface, reducing the fiber's surface energy and achieving excellent water repellency. In this way, the fibers can be properly oiled, improving spinnability without affecting their mechanical properties. At the same time, the water-repellent agent can be uniformly migrated to the fiber surface through the micro-nano structure formed on the fiber surface after acid bath, giving the fabric a long-lasting water-repellent effect without affecting the fiber's breathability. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of a circular fiber;

[0026] Figure 2 This is a cross-sectional view of the cross-shaped fiber;

[0027] Figure 3 This is a cross-sectional view of a trilobal fiber;

[0028] Figure 4 This is a cross-sectional view of a five-lobed fiber. Detailed Implementation

[0029] The test methods for the relevant performance indicators in the following embodiments and comparative examples are as follows:

[0030] Tensile strength: The tensile strength of the fibers prepared in each example and comparative example was tested in accordance with GB / T 14344-2022 "Test Method for Tensile Properties of Chemical Fiber Filaments".

[0031] Water repellency: The water repellency rating of the fabrics prepared in each example and comparative example was tested according to GB / T 4745-2012 "Determination of water repellency of textile surfaces - Water repellency test". The hydrostatic pressure resistance rating of the fabrics prepared in each example and comparative example was tested according to GB / T 4744-2013 "Test and evaluation of water-resistant properties of textiles - Hydrostatic pressure method".

[0032] Example 1: A method for preparing nylon 6 fabric, the steps of which are as follows:

[0033] (1) Preparation of nylon 6 microporous masterbatch.

[0034] According to the mass fractions, 79 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400), 10 parts of boron nitride (chip diameter 1μm, thickness 10nm), 10 parts of calcium carbonate (average particle size 80nm), and 1 part of ethylene bis-stearamide were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 microporous masterbatch. The high-speed mixer speed was 800 rpm, the mixing time was 10 min, and the extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0035] (2) Preparation of Nylon 6 water-repellent masterbatch.

[0036] According to the mass fraction, 85 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400) and 15 parts of amino-modified polysiloxane were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 water-repellent masterbatch. The high-speed mixer speed was 500 rpm and the mixing time was 5 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0037] (3) Nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade: M2400) and the above-prepared nylon 6 water-repellent masterbatch were used as core layer raw materials, wherein, by mass fraction, the nylon 6 water-repellent masterbatch accounted for 5 parts and the nylon 6 chips accounted for 95 parts. The above-prepared nylon 6 microporous masterbatch was used as the sheath layer raw material, and fibers were formed by a sheath-core composite spinning process; wherein, the spinneret orifice was "round", and the mass ratio of sheath material to core material was 20:80.

[0038] The spinning process parameters are: spinning temperature 265℃, spinning speed 5300 m / min, side blowing temperature 25℃, side blowing speed 0.4m / s, and oiling rate 1.2%.

[0039] (4) The fiber obtained in step (3) is first soaked in a citric acid bath at 30°C and pH 6 for 20 seconds, then soaked in a sodium bicarbonate bath at 30°C and pH 8.0 for 20 seconds, and finally soaked in a water bath at 30°C and pH 7 for 100 seconds. After taking it out, it is dried at 80°C to obtain microporous nylon 6 fiber.

[0040] like Figure 1 As shown, the final microporous nylon 6 fiber has a circular sheath cross-section and a circular core cross-section; the microporous nylon 6 fiber has a tensile strength of 3.72 cN / tex, a micropore number per unit area on the fiber surface of 83, and a micropore size deviation of 6%.

[0041] The microporous nylon 6 fibers obtained above are woven into fabric and knitted with a warp density of 100 threads / inch and a weft density of 80 threads / inch.

[0042] The final fabric is then heat-set at 185°C for 30 seconds with a 1% overfeed to obtain water-repellent nylon 6 fabric.

[0043] The fabric has a water repellency rating of 4 and a hydrostatic pressure resistance rating of 5 after 50 washes.

[0044] Example 2: A method for preparing nylon 6 fabric, the steps of which are as follows:

[0045] (1) Preparation of nylon 6 microporous masterbatch.

[0046] According to the mass fractions, 72 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400), 10 parts of boron nitride (sheet diameter: 1.5μm, thickness: 10nm), 15 parts of calcium carbonate (average particle size: 80nm), and 3 parts of ethylene-acrylic acid copolymer (Honeywell AC® 580) were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 microporous masterbatch. The high-speed mixer speed was 1000rpm, and the mixing time was 20min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, and Zone 12: 250℃.

[0047] (2) Preparation of Nylon 6 water-repellent masterbatch.

[0048] According to the mass fraction, 95 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400) and 5 parts of alcohol-modified polysiloxane were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 water-repellent masterbatch. The high-speed mixer speed was 700 rpm and the mixing time was 10 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0049] (3) Nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade: M2400) and the above-prepared nylon 6 water-repellent masterbatch were used as core layer raw materials, wherein, by mass fraction, the water-repellent masterbatch accounted for 10 parts and the nylon 6 chips accounted for 90 parts. The above-prepared nylon 6 microporous masterbatch was used as the sheath layer raw material, and fibers were formed by a sheath-core composite spinning process; wherein, the spinneret orifice was "cross" shaped, and the mass ratio of sheath material to core material was 30:70.

[0050] The spinning process parameters are: spinning temperature 250℃, spinning speed 6000 m / min, side blowing temperature 15℃, side blowing speed 0.3m / s, and oiling rate 0.6%.

[0051] (4) The fiber obtained in step (3) is first soaked in a citric acid bath at 40°C and pH 5.5 for 30 seconds, then soaked in a sodium bicarbonate bath at 40°C and pH 8.5 for 30 seconds, and finally soaked in a water bath at 50°C and pH 7 for 60 seconds. After taking it out, it is dried at 80°C to obtain microporous nylon 6 fiber.

[0052] like Figure 2 As shown, the final microporous nylon 6 fiber has a "cross" shaped sheath cross section and a circular core cross section; the microporous nylon 6 fiber has a breaking strength of 3.74 cN / tex, a number of micropores per unit area on the fiber surface of 118, and a micropore size deviation of 7%.

[0053] The microporous nylon 6 fibers obtained above are woven into fabric and knitted with a warp density of 110 threads / inch and a weft density of 90 threads / inch.

[0054] The final fabric is then heat-set at 180°C for 40 seconds with a 5% overfeed to obtain water-repellent nylon 6 fabric.

[0055] The fabric has a water repellency rating of 5 after 50 washes and a hydrostatic pressure resistance rating of 4.

[0056] Example 3: A method for preparing nylon 6 fabric, the steps of which are as follows:

[0057] (1) Preparation of nylon 6 microporous masterbatch.

[0058] According to the mass fractions, 85.5 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400), 8 parts of boron nitride (1 μm diameter, 10 nm thickness), 5 parts of calcium carbonate (average particle size: 80 nm), and 1.5 parts of zinc salt ionomer of ethylene-acrylic acid copolymer (Honeywell AClyn®) were copolymerized. 295A) The mixture is fed into a high-speed mixer and mixed evenly. The evenly mixed material is then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 microporous masterbatch. The high-speed mixer operates at 500 rpm and the mixing time is 5 min. The extrusion temperatures are as follows: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0059] (2) Preparation of Nylon 6 water-repellent masterbatch.

[0060] According to the mass fraction, 90 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400) and 10 parts of ester-modified polysiloxane were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 water-repellent masterbatch. The high-speed mixer speed was 800 rpm and the mixing time was 10 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0061] (3) Nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade: M2400) and the above-prepared nylon 6 water-repellent masterbatch were used as core layer raw materials, wherein, by mass fraction, the water-repellent masterbatch accounted for 15 parts and the nylon 6 chips accounted for 85 parts. Nylon 6 microporous masterbatch was used as the sheath layer raw material, and fibers were formed by a sheath-core composite spinning process; wherein, the spinneret orifice was "round", and the mass ratio of sheath material to core material was 35:65.

[0062] The spinning process parameters are: spinning temperature 263℃, spinning speed 6000 m / min, side blowing temperature 15℃, side blowing speed 0.8m / s, and oiling rate 0.6%.

[0063] (4) The fiber obtained in step (3) is first soaked in a formic acid bath at 50°C and pH 5.8 for 10 seconds, then soaked in a triethanolamine bath at 50°C and pH 8.2 for 10 seconds, and finally soaked in a water bath at 30°C and pH 7 for 120 seconds. After taking it out, it is dried at 90°C to obtain microporous nylon 6 fiber.

[0064] like Figure 1 As shown, the final microporous nylon 6 fiber has a circular sheath cross-section and a circular core cross-section; the microporous nylon 6 fiber has a breaking strength of 3.70 cN / tex, a number of micropores per unit area on the fiber surface of 80, and a micropore size deviation of 5%.

[0065] The microporous nylon 6 fibers obtained above are woven into fabric by weft knitting with a warp density of 125 threads / inch and a weft density of 100 threads / inch.

[0066] The final fabric is then heat-set at 195℃ for 50 seconds with an overfeed of 3% to obtain water-repellent nylon 6 fabric.

[0067] The fabric has a water repellency rating of 4-5 after 50 washes and a hydrostatic pressure resistance rating of 5.

[0068] Example 4: A method for preparing nylon 6 fabric, the steps of which are as follows:

[0069] (1) Preparation of nylon 6 microporous masterbatch.

[0070] According to the mass fractions, 81 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400), 10 parts of boron nitride (2μm diameter, 10nm thickness), 8 parts of calcium carbonate (average particle size: 80nm), and 1 part of a 1:1 mass ratio of ethylene bis-stearamide and ethylene-acrylic acid copolymer (Honeywell AC® 580) were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 microporous masterbatch. The high-speed mixer operated at 500 rpm for 10 minutes. min; extrusion temperatures are: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0071] (2) Preparation of Nylon 6 water-repellent masterbatch.

[0072] According to the mass fraction, 87 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400) and 13 parts of amino-modified polysiloxane were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 water-repellent masterbatch. The high-speed mixer speed was 500 rpm and the mixing time was 20 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0073] (3) Nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade: M2400) and the above-prepared nylon 6 water-repellent masterbatch were used as core layer raw materials, wherein, by mass fraction, the water-repellent masterbatch accounted for 20 parts and the nylon 6 chips accounted for 80 parts. Nylon 6 microporous masterbatch was used as the sheath layer raw material, and fibers were formed by a sheath-core composite spinning process; wherein, the spinneret orifice was "three-lobed", and the mass ratio of sheath material to core material was 40:60.

[0074] The spinning process parameters are: spinning temperature 257℃, spinning speed 4500 m / min, side blowing temperature 20℃, side blowing speed 0.5m / s, and oiling rate 0.9%.

[0075] (4) The fiber obtained in step (3) is first soaked in an acetic acid bath at 35°C and pH 6.5 for 20 seconds, then soaked in an ammonia bath at 35°C and pH 7.5 for 20 seconds, and finally soaked in a water bath at 40°C and pH 7 for 90 seconds. After taking it out, it is dried at 100°C to obtain microporous nylon 6 fiber.

[0076] like Figure 3 As shown, the final microporous nylon 6 fiber has a "trilobal" cross-section in the sheath and a circular cross-section in the core. The breaking strength of the microporous nylon 6 fiber is 3.75 cN / tex, the number of micropores per unit area on the fiber surface is 100, and the micropore size deviation is 4%.

[0077] The microporous nylon 6 fibers obtained above are woven into fabric and knitted with a warp density of 140 threads / inch and a weft density of 110 threads / inch.

[0078] The final fabric is then heat-set at 187°C for 40 seconds with a 2% overfeed to obtain water-repellent nylon 6 fabric.

[0079] The fabric has a water repellency rating of 4 after 50 washes and a hydrostatic pressure resistance rating of 4-5.

[0080] Example 5: A method for preparing nylon 6 fabric, the steps of which are as follows:

[0081] (1) Preparation of nylon 6 microporous masterbatch.

[0082] According to the mass fractions, 90 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400), 5 parts of boron nitride (chip diameter: 1.5μm, thickness: 10nm), and 5 parts of calcium carbonate (average particle size: 80nm) were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 microporous masterbatch. The high-speed mixer was operated at 700 rpm for 20 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, and Zone 12: 250℃.

[0083] (2) Preparation of Nylon 6 water-repellent masterbatch.

[0084] According to the mass fraction, 93 parts of nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade M2400) and 7 parts of alcohol-modified polysiloxane were added to a high-speed mixer and mixed evenly. The evenly mixed material was then fed into a twin-screw extruder for melt extrusion granulation to obtain nylon 6 water-repellent masterbatch. The high-speed mixer speed was 1000 rpm and the mixing time was 20 min. The extrusion temperatures were: Zone 1: 240℃, Zone 2: 270℃, Zone 3: 270℃, Zone 4: 270℃, Zone 5: 260℃, Zone 6: 260℃, Zone 7: 240℃, Zone 8: 200℃, Zone 9: 200℃, Zone 10: 200℃, Zone 11: 240℃, Zone 12: 250℃.

[0085] (3) Nylon 6 chips (manufacturer: Guangdong Hengshenmeida New Material Co., Ltd., grade: M2400) and the above-prepared nylon 6 water-repellent masterbatch were used as core layer raw materials, wherein the water-repellent masterbatch accounted for 12.5 parts and the nylon 6 chips accounted for 87.5 parts. Nylon 6 microporous masterbatch was used as the sheath layer raw material, and fibers were formed by a sheath-core composite spinning process; wherein the spinneret orifice was "five-leaf" type, and the mass ratio of sheath material to core material was 25:75.

[0086] The spinning process parameters are: spinning temperature 258℃, spinning speed 4500 m / min, side blowing temperature 20℃, side blowing speed 0.5m / s, and oiling rate 1.2%.

[0087] (4) The fiber obtained in step (3) is first soaked in a formic acid bath at 40°C and pH 6.3 for 10 seconds, then soaked in a triethanolamine bath at 40°C and pH 7.7 for 10 seconds, and finally soaked in a water bath at 35°C and pH 7 for 100 seconds. After taking it out, it is dried at 100°C to obtain microporous nylon 6 fiber.

[0088] like Figure 4 As shown, the final microporous nylon 6 fiber has a "five-leaf" shaped sheath cross-section and a circular core cross-section; the microporous nylon 6 fiber has a breaking strength of 3.73 cN / tex, 120 micropores per unit area on the fiber surface, and a micropore size deviation of 4%.

[0089] The microporous nylon 6 fibers obtained above are woven into fabric and knitted with a warp density of 150 threads / inch and a weft density of 120 threads / inch.

[0090] The final fabric is then heat-set at 192℃ for 35 seconds with an overfeed of 4% to obtain water-repellent nylon 6 fabric.

[0091] The fabric has a water repellency rating of 5 after 50 washes and a hydrostatic pressure resistance rating of 4.

[0092] Comparative Example 1: A method for preparing nylon 6 fabric is basically the same as that in Example 1, except that in step (3), only nylon 6 chips are used as the raw material for the outer layer (not nylon 6 microporous masterbatch), and the fiber is obtained by composite spinning process. The fiber used in step (4) is the one prepared in this comparative example.

[0093] The final "round" nylon 6 fiber had 0 micropores per unit area (2μm×2μm) on its surface.

[0094] The "round" nylon 6 fibers obtained above were woven into fabric, and the preparation process was basically the same as in Example 1.

[0095] The final fabric has a water repellency rating of 0 and a hydrostatic pressure rating of 0.

[0096] Comparing Comparative Example 1 and Example 1, it can be seen that the water repellency of the fabric prepared in Comparative Example 1 is significantly reduced. This is because although Comparative Example 1 and Example 1 both spun "circular" nylon 6 fibers, Example 1 formed a large number of micropores on the fiber surface. The water repellent can reach the fiber surface through the micropores, thereby greatly improving the water repellency of the fabric.

[0097] Comparative Example 2: A method for preparing nylon 6 fabric, which is basically the same as that in Example 1, except that in step (3), nylon 6 chips and the nylon 6 water-repellent masterbatch obtained in step (2) are directly mixed and spun to prepare fibers.

[0098] The final nylon 6 fiber had a breaking strength of 2.31 cN / tex and 0 micropores per unit area (2μm×2μm) on the fiber surface.

[0099] The nylon 6 fibers obtained above were woven into fabric, and the preparation process was basically the same as in Example 1.

[0100] The final fabric has a water repellency rating of 2-3 and a hydrostatic pressure rating of 2.

[0101] Comparing Comparative Example 2 with Example 1, it can be seen that the "round" nylon 6 fiber prepared in Comparative Example 2 has a significantly lower breaking strength, and the number of micropores on the fiber surface is 0. The fabric prepared using it has poor water repellency. This is because in Comparative Example 2, nylon 6 chips and nylon 6 water-repellent masterbatch are directly mixed and spun. During the spinning process, the water-repellent agent on the fiber surface greatly reduces the oiling rate, resulting in a significant decrease in the breaking strength of the entire nylon 6 fiber. Fibers with low breaking strength are prone to breakage during fabric weaving, resulting in fabric with poor uniformity, many gaps, and easy penetration of water droplets. In addition, because no micro-nano structure is formed on the fiber surface, the surface water repellency depends solely on the action of the water-repellent agent, leading to a significant decrease in the water repellency of the fabric prepared using it.

[0102] Comparative Example 3: A method for preparing nylon 6 fabric is basically the same as that in Example 1, except that in step (3), only nylon 6 chips are used as the core material and the fiber is obtained by composite spinning process, while the fiber used in step (4) is the one prepared in this comparative example.

[0103] The final "round" nylon 6 fiber had 85 micropores per unit area (2μm×2μm) on its surface.

[0104] The "round" nylon 6 fibers obtained above were woven into fabric, and the preparation process was basically the same as in Example 1.

[0105] The final fabric has a water repellency rating of 1-2 and a hydrostatic pressure rating of 1.

[0106] Comparing Comparative Example 3 and Example 1, it can be seen that the number of micropores per unit area on the surface of the "round" nylon 6 fiber obtained in Comparative Example 3 is 85. The water repellency of the fabric prepared with it is greatly reduced. This is because Comparative Example 3 did not introduce a water repellent agent into the fiber core layer. As a result, although a large number of micropores are generated on the surface of the nylon 6 fiber, the surface energy of the fiber is large due to the lack of water repellent agent, and the water repellency effect is greatly reduced.

Claims

1. A method for preparing a water-repellent nylon fabric, characterized in that, The process involves using nylon 6 chips and a water-repellent agent as raw materials, blending them, and then extruding and granulating them to obtain nylon water-repellent masterbatch. The water-repellent agent is at least one of amino, carboxyl, alcohol, or ester-modified polysiloxane. Nylon 6 chips, boron nitride, and calcium carbonate are used as raw materials, blending them, and then extruding and granulating them to obtain nylon microporous masterbatch. Then, using the nylon water-repellent masterbatch and nylon chips as core layer raw materials and the nylon microporous masterbatch as sheath layer raw materials, the fabric is formed using a core-sheath composite spinning process. After being treated with a weak acid bath to form micropores on the fiber sheath layer, it is then dried and woven after being treated with a weak alkali bath and a water bath. Finally, it is heat-set to obtain the fabric, so that the water-repellent agent in the fiber core layer can migrate to the fiber surface through the micropores.

2. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The preparation method of nylon water-repellent masterbatch is as follows: 5-15 parts by mass of water-repellent agent and 85-95 parts by mass of nylon 6 chips are blended and then melt-extruded and granulated.

3. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The preparation method of nylon microporous masterbatch is as follows: 5-10 parts by mass of boron nitride, 5-15 parts by mass of calcium carbonate, 0-3 parts by mass of dispersant and 72-90 parts by mass of nylon chips are blended and then melt-extruded and granulated.

4. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The dispersant is at least one of ethylene bis-stearamide, ethylene-acrylic acid copolymer, and zinc salt ionomer of ethylene-acrylic acid copolymer.

5. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The core material, by mass, includes 5-20 parts of nylon water-repellent masterbatch and 80-95 parts of nylon 6 chips; and the mass ratio of the core material to the sheath material is (60-80):(20-40).

6. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The process parameters for core-sheath composite spinning are as follows: spinning temperature 250-265℃, spinning speed 4500-6000m / min, side blowing temperature 15-25℃, side blowing speed 0.3-0.8m / s, and oiling rate 0.6-1.2%.

7. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The acid bath is an acetic acid bath, citric acid bath, or formic acid bath, with a pH of 5-7, a temperature of 30-50℃, and a duration of 10-30 seconds. The weak alkaline bath is an ammonia bath, a sodium bicarbonate bath, or a triethanolamine bath, with a pH of 7-9, a temperature of 30-50℃, and a duration of 10-30 seconds. The water bath temperature is 30-50℃, and the duration is 60-120 seconds. The drying temperature is 80-100℃.

8. The method for preparing the water-repellent nylon fabric according to claim 1, characterized in that, The heat setting conditions are: 180-195℃, 30-50s, overfeed 1-5%.

9. A water-repellent nylon fabric, characterized in that, Prepared by the method described in any one of claims 1-8.

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