Water-repellent chinlon fabric and preparation method thereof

Abstract

The invention discloses a water-repellent chinlon fabric and a preparation method thereof.The preparation method comprises the steps that chinlon 6 slices and a water-repellent agent serve as raw materials and are blended and then extruded and granulated to obtain chinlon water-repellent master batches, and chinlon 6 slices, boron nitride and calcium carbonate serve as raw materials and are blended and then extruded and granulated to obtain chinlon microporous master batches; taking the chinlon water-repellent master batch and chinlon slices as core layer raw materials, taking chinlon microporous master batch as skin layer raw materials, forming by adopting a skin-core composite spinning process, treating in a weak acid bath to form micropores in a fiber skin layer, drying and weaving after treating in a weak alkali bath and a clear water bath to obtain a fabric, and performing heat setting treatment to obtain the chinlon microporous fiber fabric. The water repellent in the fiber core layer is migrated to the surface of the fiber through the micropores. According to the preparation method, the water repellent can be uniformly migrated to the surface of the fiber through a micro-nano structure formed on the surface of the fiber after acid bath while the normal oiling of the fiber is ensured, the spinnability is improved, and the mechanical property of the fiber is not influenced, so that the fabric is endowed with a lasting water repellent effect.

Description

TECHNICAL FIELD

[0001] The present application relates to a water-repellent nylon fabric and a preparation method thereof, and belongs to the technical field of functional fibers. BACKGROUND

[0002] Nylon fiber (also known as polyamide fiber, commonly known as nylon) is a common synthetic fiber. The wear resistance of nylon is the most outstanding among all natural fibers and synthetic fibers, which is 10 times higher than that of cotton and 20 times higher than that of wool, far exceeding other synthetic fibers such as polyester. The fiber has high breaking strength and is less affected by humidity (wet strength is only about 10% lower than dry strength). The fabric has strong tensile and impact resistance and is not easy to break. The elastic recovery rate is high, the fabric is easy to restore to its original state after deformation, has good wrinkle resistance and shape retention. At the same time, the fiber has a specific gravity of about 1.14, which is lighter than cotton (1.54) and wool (1.32), so the fabric made of it is more comfortable to wear or carry without a heavy feeling. Therefore, nylon is widely used in outdoor sports equipment, such as sports clothing and sports shoes, which contain nylon fibers. In order to adapt to complex outdoor environments and ensure safety and comfort during sports, nylon fibers need to have water-repellent function, which indirectly plays a key role in reducing weight, preventing hypothermia and protecting performance by reducing water absorption and maintaining dryness. It is an irreplaceable functional requirement in outdoor scenarios.

[0003] There are four main methods to improve the water-repellent performance of nylon. The first method is to perform a finishing process on the fiber fabric to coat a waterproof additive on the surface of the fabric, thereby forming a thin waterproof film on the surface of the fabric to achieve good water-repellent effect. However, this waterproof film not only covers the surface of the fiber, but also blocks the gaps between the yarns, resulting in a decrease in the air permeability and moisture permeability of the fabric, which not only affects the comfort of wearing, but also makes it difficult to maintain the waterproof effect after washing. The patent CN109440476B uses this method, which coats polydimethylsiloxane, polyurethane and polyacrylate on the surface of the fabric to effectively reduce the surface tension of the fabric and achieve water-repellent effect, but at the same time, the air permeability of the fabric is sacrificed and the washability is not good.

[0004] The second method is to perform a film coating process on the surface of the fabric. However, the water-repellent textiles prepared by this method have poor air permeability and are prone to produce a stuffy feeling, thereby affecting the comfort of wearing. The patent CN103625078A uses this method, which adds nano-silver ion powder and PTFE film composite structure on the fabric to achieve waterproof function. However, the moisture absorption performance of the fabric prepared by this method is relatively weak, and the clothes may stick to the skin when sweating, causing a sticky and uncomfortable feeling.

[0005] The third method is to directly give the water-repellent property to the fiber in the fiber processing stage. It is proposed in patent CN106283608A that a treatment liquid with water-repellent effect is used to replace the traditional spinning oil in the conventional spinning process for the preparation of polyester fibers. Although this method improves the air permeability of the textile to some extent, it still has shortcomings in improving the hand feeling and functional durability of the fabric.

[0006] The fourth method is to add water-repellent components into the fiber in the form of master batch during melt spinning, so that the prepared fiber has better hand feeling and functional durability. For example, the water-repellent polyamide 6 fiber prepared by the master batch melt blending method in patent CN116970274A not only maintains the original hand feeling characteristics of polyamide 6, but also gives the woven textile the persistent water-repellent property. Compared with the post-film coating method, the textile woven from the fiber prepared by this method has better air permeability. Compared with the post-whole coating method, the textile woven from the product of this invention has the advantages of water washing resistance and air permeability. Compared with the existing treatment liquid on the spinning method, the product of this invention has the advantages of water washing resistance and more persistent water-repellent effect. However, this method has a significant disadvantage, that is, the water-repellent component is added during the fiber cooling and forming process, which will cause insufficient oiling rate of the spinning, affect the spinnability of the fiber, and reduce the mechanical properties of the fiber. SUMMARY

[0007] The purpose of the present application is to provide a water-repellent polyamide fabric and a preparation method thereof. The preparation method can ensure normal oiling of the fiber, improve the spinnability, and does not affect the mechanical properties of the fiber, while forming a micro-nano structure on the surface of the fiber during the post-treatment. During the heat setting treatment, the water-repellent agent can uniformly migrate to the surface of the fiber through the micro-nano structure, thereby giving the fabric persistent water-repellent effect without affecting the air permeability of the fiber.

[0008] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows: A preparation method of a water-repellent polyamide fabric, which uses polyamide 6 chips and a water-repellent agent as raw materials, blends them, extrudes and granulates to obtain a polyamide water-repellent master batch, uses polyamide 6 chips, boron nitride and calcium carbonate as raw materials, blends them, extrudes and granulates to obtain a polyamide microporous master batch, uses the polyamide water-repellent master batch and polyamide chips as core layer raw materials, and uses the polyamide microporous master batch as skin layer raw material, adopts a skin-core composite spinning process to form, then forms micropores on the fiber skin layer by weak acid bath treatment, and then performs weak alkali bath, water bath, drying, weaving to obtain the fabric and heat setting treatment, so that the water-repellent agent in the fiber core layer migrates to the surface of the fiber through the micropores.

[0009] Preferably, the breaking strength of the obtained fiber is 3.70-3.75 cN / tex, the number of micropores per unit area on the surface of the fiber is 80-120, and the size deviation of the micropores is not more than 10%, and the unit area refers to 2 μm x 2 μm.

[0010] Preferably, the cross section of the obtained fiber is that the core layer is "round" type, and the skin layer is "round" type, "three-leaf" type, "cross" type or "five-leaf" type.

[0011] Preferably, the preparation method of the nylon water-repellent master batch is that: 5-15 parts of water-repellent agent and 85-95 parts of nylon 6 chips are blended, and then melt extrusion granulation is carried out, and the extrusion temperature is 240-270 DEG C.

[0012] Preferably, the water-repellent agent is at least one of amino, carboxyl, alcohol group, ester group modified polysiloxane.

[0013] Preferably, the preparation method of the nylon microporous master batch is that: 5-10 parts of boron nitride, 5-15 parts of calcium carbonate, 0-3 parts of dispersing agent and 72-90 parts of nylon chips are blended, and then melt extrusion granulation is carried out, and the extrusion temperature is 240-270 DEG C.

[0014] Preferably, the dispersing agent is at least one of ethylene bis-stearamide, ethylene acrylic acid copolymer and zinc salt ionomer of ethylene acrylic acid copolymer.

[0015] Preferably, in the core layer raw material, 5-20 parts of nylon water-repellent master batch and 80-95 parts of nylon 6 chips are included according to mass fraction; and the mass ratio of the core layer raw material to the skin layer raw material is (60-80):(20-40).

[0016] Preferably, the process parameters of the skin-core composite spinning are that: the spinning temperature is 250-265 DEG C, the spinning speed is 4500-6000 m / min, the side blowing temperature is 15-25 DEG C, the side blowing speed is 0.3-0.8 m / s, and the oiling rate is 0.6-1.2%.

[0017] Preferably, the acid bath is acetic acid bath, citric acid bath or formic acid bath, the pH is 5-7, the temperature is 30-50 DEG C, and the time is 10-30 s; The weak alkali bath is ammonia water bath, sodium bicarbonate bath or triethanolamine bath, the pH is 7-9, the temperature is 30-50 DEG C, and the time is 10-30 s; The temperature of the clean water bath is 30-50 DEG C, and the time is 60-120 s.

[0018] Preferably, the heat setting condition is that: the temperature is 180-195 DEG C, the time is 30-50 s, and the overfeed is 1-5%.

[0019] A water-repellent nylon fabric is prepared by any of the above methods. The warp and weft density of the fabric is: warp density 100-150 threads / inch, weft density 80-120 threads / inch; the water absorption grade of the fabric is 4-5 grade, and the hydrostatic pressure grade is 4-5 grade.

[0020] The beneficial effects of the present application are that: The water-repellent fiber is not a conventional single-component spinning, but is prepared by composite spinning. The cross section of the core layer is circular, conventional polyamide 6 chips and water-repellent masterbatch are added, and no weak acid treatment is performed, so that no micropores appear on the surface of the skin layer, avoiding the migration of water-repellent components to the surface of the fiber during spinning to affect oiling, ensuring the spinnability and mechanical properties of the fiber. The skin layer has a circular or irregular cross section, and a microporous masterbatch is added. The microporous masterbatch contains calcium carbonate and boron nitride. Boron nitride has a heat-conducting effect, which can improve the uniformity of pore formation. Calcium carbonate can be dissolved by acid, which can be used to form micropores, and can form a micro-nano structure on the surface of the skin layer to enhance the hydrophobic effect. The polyamide 6 fiber needs to be treated with weak acid in the subsequent process. The weak acid reacts with the large amount of calcium carbonate on the surface of the fiber to leave micropores, thereby forming a micro-nano structure. Then the fabric is heat set, and the water-repellent agent in the core layer will migrate to the surface of the fiber under heat, reducing the surface energy of the fiber and achieving good water-repellent effect. In this way, the fiber can be normally oiled to improve the spinnability, and the mechanical properties of the fiber are not affected. At the same time, the water-repellent agent can be uniformly migrated to the surface of the fiber through the micro-nano structure formed on the surface of the fiber after acid treatment, giving the fabric a durable water-repellent effect without affecting the air permeability of the fiber. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is a cross-sectional view of a circular fiber; Figure 2 is a cross-sectional view of a cross-shaped fiber; Figure 3 is a cross-sectional view of a trilobal fiber; Figure 4 is a cross-sectional view of a pentalobal fiber. DETAILED DESCRIPTION

[0022] The test methods of the relevant performance indicators in the following examples and comparative examples are as follows: Breaking strength: The breaking strength of the fibers prepared in each example and each comparative example was tested according to the standard of GB / T 14344-2022 "Chemical fiber filament tensile property test method".

[0023] Water-repellent performance: The water-repellent performance of the fabric prepared in each example and each comparative example was tested according to the standard of GB / T 4745-2012 "Determination of water resistance of textile - water pick-up test". The hydrostatic pressure resistance level of the fabric prepared in each example and each comparative example was tested according to the standard of GB / T 4744-2013 "Detection and evaluation of water resistance of textile - hydrostatic pressure method".

[0024] Example 1: A preparation method of a polyamide 6 fabric, the steps are as follows: (1) Prepare a polyamide 6 microporous masterbatch.

[0025] According to the mass fraction, 79 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400), 10 parts of boron nitride (the flake diameter is 1 pm, and the thickness is 10 nm), 10 parts of calcium carbonate (the average particle diameter is 80 nm), and 1 part of ethylene bis-stearamide are put into a high-speed mixer to mix uniformly, and the uniformly mixed material is added into a twin-screw extruder to perform melt extrusion and granulation, so as to obtain a nylon 6 microporous master batch. The rotation speed of the high-speed mixer is 800 rpm, and the mixing time is 10 min. The extrusion temperature is zone 1: 240 DEG C, zone 2: 270 DEG C, zone 3: 270 DEG C, zone 4: 270 DEG C, zone 5: 260 DEG C, zone 6: 260 DEG C, zone 7: 240 DEG C, zone 8: 200 DEG C, zone 9: 200 DEG C, zone 10: 200 DEG C, zone 11: 240 DEG C, and zone 12: 250 DEG C.

[0026] (2) Preparation of nylon 6 water-repellent master batch.

[0027] According to the mass fraction, 85 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400) and 15 parts of amino-modified polysiloxane are put into a high-speed mixer to mix uniformly, and the uniformly mixed material is added into a twin-screw extruder to perform melt extrusion and granulation, so as to obtain a nylon 6 water-repellent master batch. The rotation speed of the high-speed mixer is 500 rpm, and the mixing time is 5 min. The extrusion temperature is zone 1: 240 DEG C, zone 2: 270 DEG C, zone 3: 270 DEG C, zone 4: 270 DEG C, zone 5: 260 DEG C, zone 6: 260 DEG C, zone 7: 240 DEG C, zone 8: 200 DEG C, zone 9: 200 DEG C, zone 10: 200 DEG C, zone 11: 240 DEG C, and zone 12: 250 DEG C.

[0028] (3) The nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400) and the nylon 6 water-repellent master batch prepared above are used as core layer raw materials, wherein the mass fraction of the nylon 6 water-repellent master batch is 5 parts, and the mass fraction of the nylon 6 chip is 95 parts. The nylon 6 microporous master batch prepared above is used as skin layer raw material, and a skin-core composite spinning process is adopted to form a fiber; wherein the spinneret hole is "round", and the mass ratio of the skin layer raw material to the core layer raw material is 20:80.

[0029] The spinning process parameters are as follows: spinning temperature 265 DEG C, spinning speed 5300 m / min, side blowing temperature 25 DEG C, side blowing speed 0.4 m / s, and oiling rate 1.2%.

[0030] (4) The fiber obtained in step (3) is first soaked in a citric acid bath at 30 DEG C and pH 6 for 20 s, then soaked in a sodium bicarbonate bath at 30 DEG C and pH 8.0 for 20 s, and finally soaked in a clean water bath at 30 DEG C and pH 7 for 100 s, and then dried at 80 DEG C to obtain a microporous nylon 6 fiber.

[0031] As Figure 1 shown, the skin layer cross section of the finally prepared micro-porous nylon 6 fiber is "round" type, and the core layer cross section is circular; the breaking strength of the micro-porous nylon 6 fiber is 3.72 cN / tex, the number of micro-holes per unit area of the fiber surface is 83, and the micro-hole size deviation is 6%.

[0032] The above prepared micro-porous nylon 6 fiber is woven into a fabric, which is weft-knitted, with a warp density of 100 roots / inch and a weft density of 80 roots / inch.

[0033] The finally prepared fabric is further heat set at 185°C for 30s with an overfeed of 1%, to prepare a water-repellent nylon 6 fabric.

[0034] The water absorption grade of the fabric after 50 times of washing is grade 4, and the hydrostatic pressure resistance grade is grade 5.

[0035] Example 2: A preparation method of a nylon 6 fabric, the steps are as follows: (1) Preparation of nylon 6 micro-porous masterbatch.

[0036] According to the mass fraction, 72 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meida New Material Co., Ltd., model is M2400), 10 parts of boron nitride (flake diameter is 1.5 μm, thickness is 10 nm), 15 parts of calcium carbonate (average particle size is 80 nm) and 3 parts of ethylene acrylic acid copolymer (Honeywell A-C® 580) are put into a high-speed mixer for uniform mixing, and the uniformly mixed material is added into a twin-screw extruder for melt extrusion and granulation to obtain a nylon 6 micro-porous masterbatch; wherein the rotation speed of the high-speed mixer is 1000 rpm, and the mixing time is 20 min; the extrusion temperature is zone 1: 240°C, zone 2: 270°C, zone 3: 270°C, zone 4: 270°C, zone 5: 260°C, zone 6: 260°C, zone 7: 240°C, zone 8: 200°C, zone 9: 200°C, zone 10: 200°C, zone 11: 240°C, and zone 12: 250°C.

[0037] (2) Preparation of nylon 6 water-repellent masterbatch.

[0038] According to the mass fraction, 95 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meida New Material Co., Ltd., model is M2400) and 5 parts of alcohol-based modified polysiloxane are put into a high-speed mixer for uniform mixing, and the uniformly mixed material is added into a twin-screw extruder for melt extrusion and granulation to obtain a nylon 6 water-repellent masterbatch; wherein the rotation speed of the high-speed mixer is 700 rpm, and the mixing time is 10 min; the extrusion temperature is zone 1: 240°C, zone 2: 270°C, zone 3: 270°C, zone 4: 270°C, zone 5: 260°C, zone 6: 260°C, zone 7: 240°C, zone 8: 200°C, zone 9: 200°C, zone 10: 200°C, zone 11: 240°C, and zone 12: 250°C.

[0039] (3) The polyamide 6 chip (manufacturer: Guangdong Hengshen Meida New Material Co., Ltd., brand M2400) and the water-repellent polyamide 6 master batch prepared above are used as the core layer raw material, wherein the water-repellent master batch accounts for 10 parts and the polyamide 6 chip accounts for 90 parts in terms of mass fraction. The water-repellent polyamide 6 master batch prepared above is used as the skin layer raw material, and a fiber is formed by using a skin-core composite spinning process; wherein the spinneret hole is a "cross" type, and the mass ratio of the skin layer raw material to the core layer raw material is 30:70.

[0040] The spinning process parameters are as follows: spinning temperature 250℃, spinning speed 6000 m / min, side blowing temperature 15℃, side blowing speed 0.3 m / s, and oiling rate 0.6%.

[0041] (4) The fiber obtained in step (3) is first soaked in a citric acid bath at 40℃ and pH 5.5 for 30s, then soaked in a sodium bicarbonate bath at 40℃ and pH 8.5 for 30s, and finally soaked in a clean water bath at 50℃ and pH 7 for 60s, and then dried at 80℃ to obtain a microporous polyamide 6 fiber.

[0042] As shown in Figure 2 , the cross section of the skin layer of the finally obtained microporous polyamide 6 fiber is a "cross" type, and the cross section of the core layer is circular; the breaking strength of the microporous polyamide 6 fiber is 3.74 cN / tex, the number of micropores per unit area of the fiber surface is 118, and the micropore size deviation is 7%.

[0043] The microporous polyamide 6 fiber prepared above is woven into a fabric, which is weft-knitted, with a warp density of 110 roots / inch and a weft density of 90 roots / inch.

[0044] The finally obtained fabric is subjected to heat setting at 180℃ for 40s with overfeed of 5%, to obtain a water-repellent polyamide 6 fabric.

[0045] The water absorption grade of the fabric after 50 times of washing is 5, and the hydrostatic pressure resistance grade is 4.

[0046] Example 3: A method for preparing a polyamide 6 fabric, the steps are as follows: (1) Prepare a polyamide 6 microporous master batch.

[0047] According to the mass fraction, 85.5 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400), 8 parts of boron nitride (the flake diameter is 1 μm, and the thickness is 10 nm), 5 parts of calcium carbonate (the average particle diameter is 80 nm), and 1.5 parts of zinc salt ionomer of ethylene acrylic acid copolymer (Honeywell AClyn® 295A) are put into a high-speed mixer to be uniformly mixed, and the uniformly mixed material is added into a double-screw extruder to be melt-extruded and granulated, so as to obtain a nylon 6 microporous master batch; wherein the rotating speed of the high-speed mixer is 500 rpm, and the mixing time is 5 min; the extrusion temperature is 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 ℃.

[0048] (2) Preparation of a water-repellent nylon 6 master batch.

[0049] According to the mass fraction, 90 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400) and 10 parts of ester-modified polysiloxane are put into a high-speed mixer to be uniformly mixed, and the uniformly mixed material is added into a double-screw extruder to be melt-extruded and granulated, so as to obtain a water-repellent nylon 6 master batch; wherein the rotating speed of the high-speed mixer is 800 rpm, and the mixing time is 10 min; the extrusion temperature is 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 ℃.

[0050] (3) The nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400) and the water-repellent nylon 6 master batch prepared above are used as core layer raw materials, wherein the water-repellent nylon 6 master batch accounts for 15 parts by mass fraction, and the nylon 6 chip accounts for 85 parts by mass fraction. The nylon 6 microporous master batch is used as skin layer raw material, and a fiber is formed by using a skin-core composite spinning process; wherein the spinneret hole is "round" type, and the mass ratio of the skin layer raw material to the core layer raw material is 35:65.

[0051] The spinning process parameters are as follows: spinning temperature 263 ℃, spinning speed 6000 m / min, side blowing temperature 15 ℃, side blowing speed 0.8 m / s, and oiling rate 0.6%.

[0052] (4) The fiber obtained in step (3) is first soaked in a formic acid bath at 50 ℃ and with a pH value of 5.8 for 10 s, then soaked in a triethanolamine bath at 50 ℃ and with a pH value of 8.2 for 10 s, and finally soaked in a clear water bath at 30 ℃ and with a pH value of 7 for 120 s, and after being taken out, the microporous nylon 6 fiber is dried at 90 ℃.

[0053] As shown in Figure 1 the final prepared micro-porous nylon 6 fiber has a "round" type skin layer cross-section and a circular core layer cross-section; the breaking strength of the micro-porous nylon 6 fiber is 3.70 cN / tex, the number of micro-holes per unit area of the fiber surface is 80, and the micro-hole size deviation is 5%.

[0054] The above prepared micro-porous nylon 6 fiber is woven into a fabric, and the weft knitting is 125 roots / inch in warp density and 100 roots / inch in weft density.

[0055] The final prepared fabric is subjected to heat setting at 195°C for 50s with overfeed of 3%, thereby preparing a water-repellent nylon 6 fabric.

[0056] The water absorption grade of the fabric after 50 times of washing is 4-5 grade, and the hydrostatic pressure resistance grade is 5 grade.

[0057] Example 4: A preparation method of a nylon 6 fabric, the steps are as follows: (1) Preparation of nylon 6 micro-porous masterbatch.

[0058] According to the mass fraction, 81 parts of nylon 6 chips (manufacturer is Guangdong Hengshen Meida New Material Co., Ltd., model is M2400), 10 parts of boron nitride (flake diameter is 2 μm, thickness is 10 nm), 8 parts of calcium carbonate (average particle size is 80 nm) and 1 part of a mixture of ethylene bis-stearamide and ethylene propylene acid copolymer (Honeywell A-C® 580) with a mass ratio of 1:1 are put into a high-speed mixer for uniform mixing, and the uniformly mixed material is added into a twin-screw extruder for melt extrusion and granulation, thereby obtaining a nylon 6 micro-porous masterbatch; wherein the rotation speed of the high-speed mixer is 500 rpm, and the mixing time is 10 min; the extrusion temperature is zone 1: 240°C, zone 2: 270°C, zone 3: 270°C, zone 4: 270°C, zone 5: 260°C, zone 6: 260°C, zone 7: 240°C, zone 8: 200°C, zone 9: 200°C, zone 10: 200°C, zone 11: 240°C, and zone 12: 250°C.

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

[0060] According to mass fraction, 87 parts of nylon 6 chips (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400), 13 parts of amino-modified polysiloxane were put into a high-speed mixer to mix uniformly, and the uniformly mixed material was added into a twin-screw extruder to melt extrude and granulate to obtain a water-repellent nylon 6 master batch; wherein the rotation speed of the high-speed mixer was 500 rpm, and the mixing time was 20 min; the extrusion temperature was zone 1: 240 DEG C, zone 2: 270 DEG C, zone 3: 270 DEG C, zone 4: 270 DEG C, zone 5: 260 DEG C, zone 6: 260 DEG C, zone 7: 240 DEG C, zone 8: 200 DEG C, zone 9: 200 DEG C, zone 10: 200 DEG C, zone 11: 240 DEG C, and zone 12: 250 DEG C.

[0061] (3) The nylon 6 chips (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., and the brand is M2400) and the water-repellent nylon 6 master batch prepared above were used as the core layer raw material, wherein the water-repellent master batch accounted for 20 parts and the nylon 6 chips accounted for 80 parts according to mass fraction. The nylon 6 microporous master batch was used as the skin layer raw material, and a fiber was formed by using a skin-core composite spinning process; wherein the spinneret hole was "three-leaf" type, and the mass ratio of the skin layer raw material to the core layer raw material was 40:60.

[0062] The spinning process parameters were as follows: spinning temperature 257 DEG C, spinning speed 4500 m / min, side blowing temperature 20 DEG C, side blowing speed 0.5 m / s, and oiling rate 0.9%.

[0063] (4) The fiber obtained in step (3) was first soaked in an acetic acid bath at 35 DEG C and pH 6.5 for 20 s, then soaked in an ammonia water bath at 35 DEG C and pH 7.5 for 20 s, and finally soaked in a clear water bath at 40 DEG C and pH 7 for 90 s, and then dried at 100 DEG C to obtain a microporous nylon 6 fiber.

[0064] As shown in Figure 3 , the cross section of the skin layer of the finally obtained microporous nylon 6 fiber was "three-leaf" type, and the cross section of the core layer was circular; the breaking strength of the microporous nylon 6 fiber was 3.75 cN / tex, the number of micropores per unit area of the fiber surface was 100, and the micropore size deviation was 4%.

[0065] The microporous nylon 6 fiber prepared above was woven into a fabric, and the weft knitting was performed, the warp density was 140 roots / inch, and the weft density was 110 roots / inch.

[0066] The finally obtained fabric was subjected to heat setting at 187 DEG C for 40 s and overfeed 2% to prepare a water-repellent nylon 6 fabric.

[0067] The water absorption grade of the fabric after 50 times of washing was grade 4, and the hydrostatic pressure resistance grade was grade 4-5.

[0068] Example 5: A preparation method of a nylon 6 fabric, the steps were as follows: (1) Preparation of nylon 6 microporous masterbatch.

[0069] According to the mass fraction, 90 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., brand M2400), 5 parts of boron nitride (flake diameter is 1.5 μm, thickness is 10 nm), 5 parts of calcium carbonate (average particle size is 80 nm) are put into a high-speed mixer to mix uniformly, and the uniformly mixed material is added into a twin-screw extruder to melt extrude and granulate, to obtain a nylon 6 microporous masterbatch; wherein the rotation speed of the high-speed mixer is 700 rpm, and the mixing time is 20 min; the extrusion temperature is 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℃.

[0070] (2) Preparation of nylon 6 water-repellent masterbatch.

[0071] According to the mass fraction, 93 parts of nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., brand M2400), 7 parts of alcohol-based modified polysiloxane are put into a high-speed mixer to mix uniformly, and the uniformly mixed material is added into a twin-screw extruder to melt extrude and granulate, to obtain a nylon 6 water-repellent masterbatch; wherein the rotation speed of the high-speed mixer is 1000 rpm, and the mixing time is 20 min; the extrusion temperature is 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℃.

[0072] (3) The nylon 6 chip (manufacturer is Guangdong Hengshen Meda New Material Co., Ltd., brand M2400) and the above prepared nylon 6 water-repellent masterbatch are used as core layer raw materials, wherein the water-repellent masterbatch accounts for 12.5 parts, and the nylon 6 chip accounts for 87.5 parts. The nylon 6 microporous masterbatch is used as the skin layer raw material, and a skin-core composite spinning process is adopted to form a fiber; wherein the spinneret hole is "five-leaf" type, and the mass ratio of the skin layer raw material to the core layer raw material is 25:75.

[0073] The spinning process parameters are: spinning temperature 258℃, spinning speed 4500 m / min, side blowing temperature 20℃, side blowing speed 0.5 m / s, oiling rate 1.2%.

[0074] (4) The fiber obtained in step (3) is immersed in a formic acid bath at 40°C and pH 6.3 for 10 s, then in a triethanolamine bath at 40°C and pH 7.7 for 10 s, and finally in a clean water bath at 35°C and pH 7 for 100 s, and is dried at 100°C after being taken out to obtain a microporous polyamide 6 fiber.

[0075] As shown in Figure 4 The cross section of the skin layer of the finally obtained microporous polyamide 6 fiber is "five-leaf" type, and the cross section of the core layer is circular; the breaking strength of the microporous polyamide 6 fiber is 3.73 cN / tex, the number of micropores per unit area of the fiber surface is 120, and the micropore size deviation is 4%.

[0076] The microporous polyamide 6 fiber obtained above is woven into a fabric, and the fabric is weft-knitted, with a warp density of 150 threads / inch and a weft density of 120 threads / inch.

[0077] The finally obtained fabric is subjected to heat setting at 192°C for 35 s with overfeed of 4% to obtain a water-repellent polyamide 6 fabric.

[0078] The water-logging grade of the fabric after 50 times of washing is grade 5, and the hydrostatic pressure grade is grade 4.

[0079] Comparative Example 1: A method for preparing a polyamide 6 fabric is basically the same as that of Example 1, except that in step (3), only polyamide 6 chips are used as the raw material for the skin layer (non-microporous polyamide 6 master batch), and a composite spinning process is used to obtain the fiber, and in step (4), the fiber used is obtained in this comparative example.

[0080] The number of micropores per unit area (2 μm x 2 μm) of the fiber surface of the finally obtained "circular" polyamide 6 fiber is 0.

[0081] The "circular" polyamide 6 fiber obtained above is woven into a fabric, and the preparation process is basically the same as that of Example 1.

[0082] The water-logging grade of the finally obtained fabric is grade 0, and the hydrostatic pressure grade is grade 0.

[0083] It can be known from the comparison between Comparative Example 1 and Example 1 that the water-repellent performance of the fabric obtained in Comparative Example 1 decreases obviously, because although Comparative Example 1 also spins "circular" polyamide 6 fiber, on the basis of which a large number of micropores are formed on the fiber surface in Example 1, the water-repellent agent can reach the fiber surface through the micropores, thereby greatly improving the water-repellent performance of the fabric.

[0084] Comparative Example 2: A method for preparing a polyamide 6 fabric is basically the same as that of Example 1, except that in step (3), polyamide 6 chips and the polyamide 6 water-repellent master batch obtained in step (2) are directly mixed to spin the fiber.

[0085] The breaking strength of the final prepared polyamide 6 fiber is 2.31 cN / tex, and the number of micropores per unit area (2 pm x 2 pm) on the fiber surface is 0.

[0086] The above prepared polyamide 6 fiber is woven into a fabric, and the preparation process is basically the same as that of Example 1.

[0087] The final prepared fabric has a water absorption level of 2-3 and a hydrostatic pressure level of 2.

[0088] Comparing Example 1 with Comparative Example 2, it can be seen that the breaking strength of the "round" polyamide 6 fiber prepared in Comparative Example 2 decreases significantly, and the number of micropores on the fiber surface is 0. The water repellent performance of the fabric prepared therefrom is poor, because in Comparative Example 2, the polyamide 6 chip and the polyamide 6 water repellent master batch are directly mixed for spinning, and the water repellent agent on the fiber surface greatly reduces the oiling rate during the spinning process, resulting in a significant decrease in the breaking strength of the whole polyamide 6 fiber. The fiber with low breaking strength is prone to breakage during fabric weaving, so the fabric has poor uniformity, many gaps, and water droplets can easily penetrate through these gaps. In addition, because no micro-nano structure is formed on the fiber surface, the water repellent performance of the surface depends only on the action of the water repellent agent, which greatly reduces the water repellent effect of the fabric prepared therefrom.

[0089] Comparative Example 3: A method for preparing a polyamide 6 fabric, which is basically the same as Example 1, except that in step (3), only polyamide 6 chips are used as the core layer raw material, and a composite spinning process is used to prepare the fiber, and in step (4), the fiber prepared in this comparative example is used.

[0090] The number of micropores per unit area (2 pm x 2 pm) on the surface of the final prepared "round" polyamide 6 fiber is 85.

[0091] The above prepared "round" polyamide 6 fiber is woven into a fabric, and the preparation process is basically the same as that of Example 1.

[0092] The final prepared fabric has a water absorption level of 1-2 and a hydrostatic pressure level of 1.

[0093] Comparing Example 1 with Comparative Example 3, it can be seen that the number of micropores per unit area on the surface of the "round" polyamide 6 fiber prepared in Comparative Example 3 is 85, and the water repellent performance of the fabric prepared therefrom is greatly reduced, because in Comparative Example 3, no water repellent agent is introduced into the fiber core layer, resulting in a large number of micropores on the surface of the prepared polyamide 6 fiber, but no water repellent agent is attached, the surface energy of the fiber is large, and the water repellent effect is greatly reduced.

Claims

1. A method for preparing a water-repellent nylon fabric, characterized in that: Nylon 6 chips and water repellent are used as raw materials, which are extruded and granulated to obtain nylon water repellent masterbatch. Nylon 6 chips, boron nitride and calcium carbonate are used as raw materials, which are extruded and granulated to obtain nylon microporous masterbatch. Nylon water repellent masterbatch and nylon chips are used as core layer raw materials, and nylon microporous masterbatch is used as skin layer raw material. After forming by skin-core composite spinning process, the fiber is treated in a weak acid bath to form micropores on the fiber skin layer. The fiber is then treated in a weak alkali bath and a clean water bath, dried, woven to obtain the fabric, and heat-set, so that the water repellent 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, wherein: The preparation method of nylon water-repellent masterbatch is as follows: 5-15 parts of water-repellent and 85-95 parts of nylon 6 chips are blended according to weight, and then melt-extrusion granulation is performed.

3. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: The water repellent is at least one of amino-, carboxyl-, alcohol-, and ester-modified polysiloxanes.

4. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: The preparation method of nylon microporous masterbatch is as follows: after blending 5-10 parts of boron nitride, 5-15 parts of calcium carbonate, 0-3 parts of dispersant and 72-90 parts of nylon chips according to weight proportions, the mixture is melt-extruded and granulated.

5. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: The dispersant is at least one of ethylene bisstearamide, ethylene acrylic acid copolymer and ethylene acrylic acid copolymer zinc salt ionomer.

6. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: The core layer raw materials include 5-20 parts of nylon water-repellent masterbatch and 80-95 parts of nylon 6 chips in parts by mass; and the mass ratio of the core layer raw materials to the skin layer raw materials is (60-80):(20-40).

7. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: The process parameters of the sheath-core composite spinning 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%.

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

9. The method for preparing the water-repellent nylon fabric according to claim 1, wherein: Heat setting conditions are: 180-195℃, 30-50s, overfeed 1-5%.

10. A water-repellent nylon fabric, characterized in that: The method is prepared by any one of claims 1 to 9.

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