Moisture-permeable multi-layer composite fabric and preparation method thereof

Abstract

The present invention relates to the technical field of functional fabrics, specifically to the technical field of patent classification number D01F6 / 00, and discloses a moisture-permeable multi-layer composite fabric and a preparation method thereof. The moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer that are bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric. The preparation method comprises coating both sides of the middle layer with an adhesive, then stacking the inner layer and the outer layer above and below the middle layer respectively, and then placing them in a laminating device for hot pressing treatment, and cooling to obtain the result. The multi-layer composite fabric of the present invention has both good moisture permeability and breathability.

Description

Technical Field

[0001] The present invention relates to the technical field of functional fabrics, specifically to the technical field of patent classification number D01F6 / 00, and specifically to a moisture-permeable multi-layer composite fabric and a preparation method thereof. Background Art

[0002] In the field of textile materials, fabric performance has always been the focus of research and application. With the improvement of people's quality of life and the growing demand for functional clothing and fabric products, higher requirements are placed on the moisture permeability of fabrics.

[0003] Traditional single-layer fabrics have a simple structure, a relatively convenient production process, and low cost. For example, common pure cotton single-layer fabrics have good skin-friendliness and are widely used in daily life. Ordinary T-shirts, shirts, etc. are mostly made of this material. However, due to its single structure, single-layer fabrics have obvious shortcomings in functionality. In terms of moisture permeability, pure cotton single-layer fabrics rely solely on the gaps in the fibers themselves to achieve water vapor transmission. When the external humidity is high or the human body sweats profusely, its moisture permeability is low, and sweat cannot be discharged quickly, resulting in a damp and sticky feeling on the wearer's skin surface, seriously affecting the comfort of wearing. Moreover, single-layer fabrics lack sufficient protection and durability when facing complex usage environments, making it difficult to meet the needs of special scenarios.

[0004] To address the shortcomings of single-layer fabrics, multi-layer fabrics have emerged. These fabrics typically combine materials with different functions through specialized processes to achieve a combination of properties. For example, some multi-layer fabrics feature a waterproof outer layer and a warm inner layer, finding application in outdoor clothing. However, in practice, the moisture permeability of most multi-layer fabrics remains unsatisfactory.

[0005] Furthermore, differences in the moisture permeability of different materials can also limit the overall moisture permeability of multi-layer fabrics. When the outer layer is made of a polymer film material with excellent waterproof properties but poor moisture permeability, even if the inner layer is made of a fabric with good moisture permeability, the outer film will block moisture vapor from escaping smoothly, severely restricting the moisture permeability of the entire multi-layer fabric. This type of multi-layer fabric with poor moisture permeability cannot promptly expel sweat produced by the human body during exercise or labor, causing discomfort to the user. Long-term exposure to humid environments can also cause skin diseases, shorten the service life of the garment, and limit its application in a wider range of fields.

[0006] In summary, both single-layer and existing multi-layer fabrics suffer from poor moisture permeability, which significantly limits their further development and application in a variety of fields, including clothing, medical treatment, and outdoor products. Therefore, the development of a multi-layer composite fabric with excellent moisture permeability and its preparation method are of great practical significance and market demand, effectively filling the gap in existing technology and meeting people's demand for high-performance fabrics. Summary of the Invention

[0007] The purpose of the present invention is to provide a moisture-permeable multi-layer composite fabric and a preparation method thereof to solve the technical problem of poor moisture permeability of fabrics raised in the above-mentioned background art. The multi-layer composite fabric of the present invention has both good moisture permeability and air permeability.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer which are bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric.

[0010] The moisture-permeable multi-layer composite fabric of the present invention has good moisture permeability. The bamboo fiber fabric in the inner layer can quickly absorb moisture emitted by the human body. In addition, bamboo fiber has natural antibacterial and deodorizing properties, which can effectively inhibit bacterial growth, reduce the generation of odor, and bring a fresh and comfortable feeling to the skin. At the same time, the bamboo fiber has a soft texture and a delicate touch, which can reduce friction when in contact with the skin, further improving the comfort of the inner layer, allowing the user to feel a soft cloud-like wrapping during wearing, greatly improving the pleasure and experience of wearing. The middle layer is made of polypropylene non-woven fabric, which has high strength and a relatively tough texture. It can provide a good support structure for the entire composite fabric, making it not easy to deform during use and maintain a stable shape. In addition, the polypropylene non-woven fabric has good chemical stability and is not easy to react with other substances. It has a long service life and good durability. The outer layer of the polytetrafluoroethylene microporous membrane and the high-count cotton fiber fabric composite layer can effectively block the entry of external moisture while quickly discharging moisture, keeping the human body dry and comfortable, and the overall structure is stable.

[0011] Preferably, the polypropylene non-woven fabric is made from modified polypropylene fiber.

[0012] Preferably, the preparation method of the modified polypropylene fiber comprises the following steps:

[0013] S1. Adding nano-montmorillonite to deionized water and stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding hexadecyltrimethylammonium bromide to the suspension, continuing to stir evenly, then heating to 60° C. and stirring for 7 hours, followed by centrifugation, washing, and drying to obtain modified nano-montmorillonite;

[0014] S2, adding the modified nano-montmorillonite to anhydrous ethanol, uniformly dispersing it by ultrasonic oscillation, then adding polypropylene resin, stirring and mixing uniformly, removing the anhydrous ethanol by rotary evaporator to obtain a mixed masterbatch, adding the mixed masterbatch to a screw extruder for melt blending and granulation to obtain nano-montmorillonite masterbatch;

[0015] S3, adding nano-montmorillonite masterbatch into the spinning machine barrel, using a metering pump to accurately control the melt extrusion amount, spinning at a spinning speed of 1200-1800 m / min to obtain spun fibers, stretching the spun fibers, and then performing heat setting treatment to obtain montmorillonite-doped polypropylene fibers;

[0016] S4. Plasma-treating the montmorillonite-doped polypropylene fiber using a low-temperature plasma device to introduce more oxygen-containing hydrophilic groups onto the surface of the montmorillonite-doped polypropylene fiber to obtain plasma-treated polypropylene fiber;

[0017] S5. Add acrylic acid to deionized water, heat and stir to dissolve, to obtain an acrylic acid solution, then add ammonium persulfate initiator, stir evenly, then immerse the plasma-treated polypropylene fiber in the above solution, keep warm for reaction, repeatedly wash the treated fiber with deionized water to remove residual chemical reagents on the surface, place in an oven and dry to constant weight to obtain modified polypropylene fiber.

[0018] In the technical solution of the present invention, as described above, the middle layer of the multi-layer composite fabric adopts polypropylene non-woven fabric, but the moisture conductivity of ordinary polypropylene fiber has certain limitations. Although it has the advantages of wicking effect and hydrophobicity that are conducive to moisture conduction, its moisture absorption capacity is limited and is greatly affected by the environment, which cannot meet the needs of high-performance moisture-permeable fabrics. The present invention adopts a series of methods to modify it. First, nano-montmorillonite is added to deionized water and reacted with hexadecyltrimethylammonium bromide to obtain modified nano-montmorillonite, which is then dispersed in anhydrous ethanol and mixed with polypropylene resin to granulate to obtain nano-montmorillonite masterbatch. This is because nano-montmorillonite has a layered structure and a large specific surface area, which can form microporous channels and increase the specific surface area in the polypropylene matrix, providing a path for water vapor transmission and increasing the contact area with water vapor. At the same time, its water vapor adsorption and release characteristics also help to improve moisture conductivity. The masterbatch is then spun, stretched and heat-set to obtain montmorillonite-doped polypropylene fiber, which is then treated with a low-temperature plasma device to introduce oxygen-containing hydrophilic groups on the fiber surface, improve surface roughness and surface energy, and improve hydrophilicity and moisture conductivity. Finally, the plasma-treated polypropylene fiber is immersed in an acrylic acid solution containing ammonium persulfate initiator for grafting modification. The hydrophilic groups such as the carboxyl group of the acrylic acid molecule further enhance the hydrophilicity of the fiber, forming a hydrophilic network structure and promoting water vapor transmission. The grafted polymer layer improves the functionality and stability of the fiber, so that the modified polypropylene fiber can be better used in moisture-permeable multi-layer composite fabrics, thereby improving the moisture permeability of the overall fabric.

[0019] The present invention adds nano-montmorillonite to polypropylene fibers. While this improves the fibers' moisture conductivity, it also presents a further problem: the addition alters the rheological properties of the melt, reducing the mechanical strength of the polypropylene, causing broken fibers, and deteriorating its spinnability. To address this issue, the present invention modifies the nano-montmorillonite by inserting cetyltrimethylammonium bromide between the montmorillonite interlayers through an ion exchange reaction. On the one hand, van der Waals forces exist between the long-chain alkyl groups (hexadecyl groups) in the cetyltrimethylammonium bromide and the molecular chains of the polypropylene fibers. This intermolecular force enhances the mutual attraction between the montmorillonite and the polypropylene fibers. On the other hand, the ion exchange reaction alters the charge distribution between the montmorillonite interlayers, generating electrostatic interactions with any polar groups in the polypropylene fibers, further strengthening the bond between the two. Through the synergistic effect of these forces, the comprehensive bonding force between montmorillonite and polypropylene fiber is significantly improved, effectively avoiding the decrease in the mechanical strength of polypropylene fiber caused by the addition of montmorillonite, and ensuring that while using nano-montmorillonite and acrylic acid to improve the moisture conductivity of polypropylene fiber, the good performance of polypropylene fiber in other aspects such as mechanical strength is maintained.

[0020] Preferably, in step S1, the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is 1:0.3-0.5.

[0021] In the technical solution of the present invention, in order to avoid the negative impact of nano-montmorillonite on the mechanical properties of polypropylene fiber, a sufficient amount of hexadecyltrimethylammonium bromide must be intercalated into the nano-montmorillonite. When the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is controlled to be less than 1:0.3, the hexadecyltrimethylammonium bromide intercalated into the nano-montmorillonite significantly improves the mechanical strength of the polypropylene fiber. However, the team of the present invention unexpectedly discovered that the air permeability of some non-woven fabrics made of polypropylene fibers has dropped significantly, which in turn leads to a decrease in the air permeability of multi-layer fabrics. After in-depth research, it was found that this problem has an important influence on the amount of hexadecyltrimethylammonium bromide intercalated into the nano-montmorillonite. When an excessive amount of hexadecyltrimethylammonium bromide must be intercalated into the nano-montmorillonite, the hexadecyltrimethylammonium bromide fills the internal pores and molecular chains of the polypropylene fiber, blocking the gas channel, significantly reducing the air permeability of the fiber and affecting the comfort of use. Therefore, the present invention also strictly controls the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide to be greater than 1:0.5.

[0022] Preferably, in step S3, the spinning temperature is controlled at 170-180°C.

[0023] Preferably, in step S5, the insulation reaction temperature is 65-70° C., and the insulation reaction is carried out for 2-3 hours.

[0024] Preferably, the method for preparing the composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric comprises the following steps:

[0025] The polytetrafluoroethylene microporous membrane is subjected to plasma treatment to increase its surface activity to obtain a pretreated polytetrafluoroethylene microporous membrane, an adhesive is coated on the surface of the pretreated polytetrafluoroethylene microporous membrane, a high-count cotton fiber fabric is covered on the pretreated polytetrafluoroethylene microporous membrane to make the two closely fit together, and hot pressing is performed to shape the membrane, and the membrane is cooled to obtain the membrane.

[0026] The outer layer of the multi-layer moisture-permeable fabric of the present invention is a composite of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric. The polytetrafluoroethylene microporous membrane is first subjected to a plasma treatment to increase its surface activity, thereby better bonding with the adhesive and allowing the adhesive to be more evenly coated on its surface. The high-count cotton fiber fabric is then covered and tightly fitted, followed by hot pressing and shaping, ensuring a firm and tight connection between the two. The hot pressing and shaping process can make the structure of the composite layer more stable. After cooling, the resulting composite layer has good integrity and stability, and can fully utilize the excellent properties of the polytetrafluoroethylene microporous membrane (such as breathability and waterproofness) and the softness and comfort of the high-count cotton fiber fabric, so that the composite layer can exhibit excellent comprehensive performance in practical applications.

[0027] Preferably, the pore size of the polytetrafluoroethylene microporous membrane is 0.1-0.5 μm and the thickness is 0.05-0.1 mm.

[0028] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0029] The adhesive is applied to both sides of the middle layer, and then the inner layer and the outer layer are respectively stacked on the upper and lower sides of the middle layer, and then placed in a laminating device for heat pressing treatment, and cooled to obtain the product.

[0030] Preferably, the adhesive is a polyurethane adhesive.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Multi-layer composite structure design: the inner layer of bamboo fiber fabric quickly absorbs moisture, the middle layer of modified polypropylene non-woven fabric improves moisture conduction, and the outer layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric composite layer quickly discharges moisture, solving the problem of poor moisture permeability of the fabric;

[0033] 2. Modify the polypropylene fiber by adding nano-montmorillonite and a series of treatments, such as reaction with hexadecyltrimethylammonium bromide, low-temperature plasma treatment, and acrylic acid grafting, to improve its moisture conductivity. At the same time, specific modification methods are used to avoid the loss of mechanical strength, ensure spinnability, and maintain overall performance.

[0034] 3. Strictly control the mass ratio of nano-montmorillonite and hexadecyltrimethylammonium bromide to balance mechanical strength and air permeability. DETAILED DESCRIPTION

[0035] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the implementation regulations described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0036] Example 1

[0037] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; the polypropylene non-woven fabric is prepared from modified polypropylene fiber by a needle-punching method.

[0038] The preparation method of modified polypropylene fiber comprises the following steps:

[0039] S1. Adding nano-montmorillonite to deionized water at a mass volume ratio of 1 g / 50 mL, stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding cetyltrimethylammonium bromide to the suspension at a mass ratio of nano-montmorillonite to cetyltrimethylammonium bromide of 1:0.45, continuing to stir evenly, then heating to 60° C., stirring for 7 hours, and centrifuging, washing, and drying to obtain modified nano-montmorillonite;

[0040] S2. Add the modified nano-montmorillonite to anhydrous ethanol at a mass volume ratio of 1 g / 20 mL, disperse evenly by ultrasonic oscillation, then add polypropylene resin, the mass ratio of the modified nano-montmorillonite to the polypropylene resin is 1:60, stir and mix evenly, remove the anhydrous ethanol by a rotary evaporator to obtain a mixed masterbatch, add the mixed masterbatch to a screw extruder for melt blending and granulation, control the extrusion temperature at 150° C., and the screw speed at 200 r / min to obtain a nano-montmorillonite masterbatch;

[0041] S3. Adding nano-montmorillonite masterbatch into the spinning barrel of a spinning machine, controlling the spinning temperature at 175° C., using a metering pump to accurately control the melt extrusion rate, spinning at a spinning speed of 1700 m / min to obtain spun fibers, stretching the spun fibers at a stretching ratio of 3.5 times and a stretching temperature of 90° C., and then performing a heat setting treatment at 120° C. to obtain montmorillonite-doped polypropylene fibers;

[0042] S4. Plasma-treating the montmorillonite-doped polypropylene fiber for 3 minutes using a low-temperature plasma device with a plasma treatment power controlled at 100 W to introduce more oxygen-containing hydrophilic groups onto the surface of the fiber, thereby obtaining plasma-treated polypropylene fiber.

[0043] S5. Add acrylic acid to deionized water, heat and stir to dissolve, and prepare an acrylic acid solution with a mass concentration of 5%. Then add ammonium persulfate initiator, the amount of ammonium persulfate added is 3% of the mass of acrylic acid, stir evenly, and then immerse the plasma-treated polypropylene fiber in the above solution according to a bath ratio of 1:30. Keep the temperature at 68°C for 2.5 hours. The treated fiber is repeatedly washed with deionized water to remove the chemical reagents remaining on the surface, and placed in an oven to dry to constant weight to obtain modified polypropylene fiber.

[0044] Preparation of composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric:

[0045] A polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.4 μm and a thickness of 0.08 mm was selected and wiped with an ethanol cotton ball and dried with nitrogen. A high-count cotton fabric with a count of 120 was selected and desized by soaking in a 0.5% sodium hydroxide solution for 30 minutes, rinsed with clean water until neutral, and then dried at 80°C for 2 hours. A silicone adhesive was also applied, preheated in a 40°C water bath for 30 minutes and stirred until the viscosity reached 600 mPa·s. The PTFE microporous membrane was placed in a plasma treatment apparatus and treated at 150 W for 5 minutes to obtain a pretreated PTFE microporous membrane. Next, a 0.02 mm thick layer of adhesive was evenly applied to the surface of the pretreated membrane using a scraper at a 45° angle and a speed of 10 cm / s. The dried high-count cotton fabric was then placed on top and rolled twice with a rubber roller to remove air and form a tight fit. Then, put it into the hot pressing equipment, hot press it at 150°C and 0.5MPa for 5 minutes, and cool it to obtain the product.

[0046] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0047] The middle fabric was laid flat on a clean, dry and well-ventilated operating table, and a polyurethane adhesive with a viscosity of 600 mPa·s was evenly coated on both sides of the middle fabric. During the coating process, the thickness of the adhesive was controlled to 0.1 mm. Then, the pre-treated inner fabric was flatly superimposed on the middle fabric to ensure that the two were tightly fitted without wrinkles or offset. At the same time, the outer fabric was superimposed on the bottom of the middle fabric. Subsequently, the two were transferred to a laminating device for hot pressing. The hot pressing temperature was between 130°C, the pressure was controlled at 0.8 MPa, and the hot pressing time was controlled at 5 minutes. The product was then cooled.

[0048] Example 2

[0049] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; the polypropylene non-woven fabric is prepared from modified polypropylene fiber by a needle-punching method.

[0050] The preparation method of modified polypropylene fiber comprises the following steps:

[0051] S1. Adding nano-montmorillonite to deionized water at a mass volume ratio of 1 g / 50 mL, stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding cetyltrimethylammonium bromide to the suspension at a mass ratio of nano-montmorillonite to cetyltrimethylammonium bromide of 1:0.35, continuing to stir evenly, then heating to 60° C., stirring for 7 hours, and centrifuging, washing, and drying to obtain modified nano-montmorillonite;

[0052] S2. Add the modified nano-montmorillonite to anhydrous ethanol at a mass volume ratio of 1 g / 20 mL, disperse evenly by ultrasonic oscillation, then add polypropylene resin, the mass ratio of the modified nano-montmorillonite to the polypropylene resin is 1:60, stir and mix evenly, remove the anhydrous ethanol by a rotary evaporator to obtain a mixed masterbatch, add the mixed masterbatch to a screw extruder for melt blending and granulation, control the extrusion temperature at 150° C., and the screw speed at 200 r / min to obtain a nano-montmorillonite masterbatch;

[0053] S3. Adding nano-montmorillonite masterbatch into the spinning barrel of a spinning machine, controlling the spinning temperature at 175° C., using a metering pump to accurately control the melt extrusion rate, spinning at a spinning speed of 1300 m / min to obtain spun fibers, stretching the spun fibers at a stretching ratio of 3.5 times and a stretching temperature of 90° C., and then performing a heat setting treatment at 120° C. to obtain montmorillonite-doped polypropylene fibers;

[0054] S4. Plasma-treating the montmorillonite-doped polypropylene fiber for 3 minutes using a low-temperature plasma device with a plasma treatment power controlled at 100 W to introduce more oxygen-containing hydrophilic groups onto the surface of the fiber, thereby obtaining plasma-treated polypropylene fiber.

[0055] S5. Add acrylic acid to deionized water, heat and stir to dissolve, and prepare an acrylic acid solution with a mass concentration of 5%. Then add ammonium persulfate initiator, the amount of ammonium persulfate added is 3% of the mass of acrylic acid, stir evenly, and then immerse the plasma-treated polypropylene fiber in the above solution according to a bath ratio of 1:30. Keep the temperature at 68°C for 2.5 hours. The treated fiber is repeatedly washed with deionized water to remove the chemical reagents remaining on the surface, and placed in an oven to dry to constant weight to obtain modified polypropylene fiber.

[0056] Preparation of composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric:

[0057] A polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.2 μm and a thickness of 0.06 mm was selected and wiped with an ethanol cotton ball and blown dry with nitrogen. A high-count cotton fabric with a count of 120 was selected and desized by soaking in a 0.5% sodium hydroxide solution for 30 minutes, rinsed with clean water until neutral, and then dried at 80°C for 2 hours. A silicone adhesive was also applied, preheated in a 40°C water bath for 30 minutes and stirred until the viscosity reached 600 mPa·s. The PTFE microporous membrane was placed in a plasma treatment apparatus and treated at 150 W for 5 minutes to obtain a pretreated PTFE microporous membrane. Next, a 0.02 mm thick layer of adhesive was evenly applied to the surface of the pretreated membrane using a scraper at a 45° angle and a speed of 10 cm / s. The dried high-count cotton fabric was then placed on top and rolled twice with a rubber roller to remove air and form a tight fit. Then, put it into the hot pressing equipment, hot press it at 150°C and 0.5MPa for 5 minutes, and cool it to obtain the product.

[0058] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0059] The middle fabric was laid flat on a clean, dry and well-ventilated operating table, and a polyurethane adhesive with a viscosity of 600 mPa·s was evenly coated on both sides of the middle fabric. During the coating process, the thickness of the adhesive was controlled to 0.1 mm. Then, the pre-treated inner fabric was flatly superimposed on the middle fabric to ensure that the two were tightly fitted without wrinkles or offset. At the same time, the outer fabric was superimposed on the bottom of the middle fabric. Subsequently, the two were transferred to a laminating device for hot pressing. The hot pressing temperature was between 130°C, the pressure was controlled at 0.8 MPa, and the hot pressing time was controlled at 5 minutes. The product was then cooled.

[0060] Example 3

[0061] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; the polypropylene non-woven fabric is prepared from modified polypropylene fiber by a needle-punching method.

[0062] The preparation method of modified polypropylene fiber comprises the following steps:

[0063] S1. Adding nano-montmorillonite to deionized water at a mass volume ratio of 1 g / 50 mL, stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding cetyltrimethylammonium bromide to the suspension at a mass ratio of nano-montmorillonite to cetyltrimethylammonium bromide of 1:0.4, continuing to stir evenly, then heating to 60° C., stirring for 7 hours, and centrifuging, washing, and drying to obtain modified nano-montmorillonite;

[0064] S2. Add the modified nano-montmorillonite to anhydrous ethanol at a mass volume ratio of 1 g / 20 mL, disperse evenly by ultrasonic oscillation, then add polypropylene resin, the mass ratio of the modified nano-montmorillonite to the polypropylene resin is 1:60, stir and mix evenly, remove the anhydrous ethanol by a rotary evaporator to obtain a mixed masterbatch, add the mixed masterbatch to a screw extruder for melt blending and granulation, control the extrusion temperature at 150° C., and the screw speed at 200 r / min to obtain a nano-montmorillonite masterbatch;

[0065] S3. Adding nano-montmorillonite masterbatch into the spinning barrel of a spinning machine, controlling the spinning temperature at 175° C., using a metering pump to accurately control the melt extrusion rate, spinning at a spinning speed of 1500 m / min to obtain spun fibers, stretching the spun fibers at a stretching ratio of 3.5 times and a stretching temperature of 90° C., and then performing a heat setting treatment at 120° C. to obtain montmorillonite-doped polypropylene fibers;

[0066] S4. Plasma-treating the montmorillonite-doped polypropylene fiber for 3 minutes using a low-temperature plasma device with a plasma treatment power controlled at 100 W to introduce more oxygen-containing hydrophilic groups onto the surface of the fiber, thereby obtaining plasma-treated polypropylene fiber.

[0067] S5. Add acrylic acid to deionized water, heat and stir to dissolve, and prepare an acrylic acid solution with a mass concentration of 5%. Then add ammonium persulfate initiator, the amount of ammonium persulfate added is 3% of the mass of acrylic acid, stir evenly, and then immerse the plasma-treated polypropylene fiber in the above solution according to a bath ratio of 1:30. Keep the temperature at 68°C for 2.5 hours. The treated fiber is repeatedly washed with deionized water to remove the chemical reagents remaining on the surface, and placed in an oven to dry to constant weight to obtain modified polypropylene fiber.

[0068] Preparation of composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric:

[0069] A polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.3 μm and a thickness of 0.07 mm was selected and wiped with an ethanol cotton ball and dried with nitrogen. A high-count cotton fabric with a count of 120 was selected and desized by soaking in a 0.5% sodium hydroxide solution for 30 minutes, rinsed with clean water until neutral, and then dried at 80°C for 2 hours. A silicone adhesive was also applied, preheated in a 40°C water bath for 30 minutes and stirred until the viscosity reached 600 mPa·s. The PTFE microporous membrane was placed in a plasma treatment apparatus and treated at 150 W for 5 minutes to obtain a pretreated PTFE microporous membrane. Next, a 0.02 mm thick layer of adhesive was evenly applied to the surface of the pretreated membrane using a scraper at a 45° angle and a speed of 10 cm / s. The dried high-count cotton fabric was then placed on top and rolled twice with a rubber roller to remove air and form a tight fit. Then, put it into the hot pressing equipment, hot press it at 150°C and 0.5MPa for 5 minutes, and cool it to obtain the product.

[0070] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0071] The middle fabric was laid flat on a clean, dry and well-ventilated operating table, and a polyurethane adhesive with a viscosity of 600 mPa·s was evenly coated on both sides of the middle fabric. During the coating process, the thickness of the adhesive was controlled to 0.1 mm. Then, the pre-treated inner fabric was flatly superimposed on the middle fabric to ensure that the two were tightly fitted without wrinkles or offset. At the same time, the outer fabric was superimposed on the bottom of the middle fabric. Subsequently, the two were transferred to a laminating device for hot pressing. The hot pressing temperature was between 130°C, the pressure was controlled at 0.8 MPa, and the hot pressing time was controlled at 5 minutes. The product was then cooled.

[0072] Example 4

[0073] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; the polypropylene non-woven fabric is prepared from modified polypropylene fiber by a needle-punching method.

[0074] The preparation method of modified polypropylene fiber comprises the following steps:

[0075] S1. Adding nano-montmorillonite to deionized water at a mass volume ratio of 1 g / 50 mL, stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding cetyltrimethylammonium bromide to the suspension at a mass ratio of nano-montmorillonite to cetyltrimethylammonium bromide of 1:0.5, continuing to stir evenly, then heating to 60° C., stirring for 7 hours, and centrifuging, washing, and drying to obtain modified nano-montmorillonite;

[0076] S2. Add the modified nano-montmorillonite to anhydrous ethanol at a mass volume ratio of 1 g / 20 mL, disperse evenly by ultrasonic oscillation, then add polypropylene resin, the mass ratio of the modified nano-montmorillonite to the polypropylene resin is 1:60, stir and mix evenly, remove the anhydrous ethanol by a rotary evaporator to obtain a mixed masterbatch, add the mixed masterbatch to a screw extruder for melt blending and granulation, control the extrusion temperature at 150° C., and the screw speed at 200 r / min to obtain a nano-montmorillonite masterbatch;

[0077] S3. Adding nano-montmorillonite masterbatch into the spinning barrel of a spinning machine, controlling the spinning temperature at 180° C., using a metering pump to accurately control the melt extrusion rate, spinning at a spinning speed of 1800 m / min to obtain spun fibers, stretching the spun fibers at a stretching ratio of 3.5 times and a stretching temperature of 90° C., and then performing a heat setting treatment at 120° C. to obtain montmorillonite-doped polypropylene fibers;

[0078] S4. Plasma-treating the montmorillonite-doped polypropylene fiber for 3 minutes using a low-temperature plasma device with a plasma treatment power controlled at 100 W to introduce more oxygen-containing hydrophilic groups onto the surface of the fiber, thereby obtaining plasma-treated polypropylene fiber.

[0079] S5. Add acrylic acid to deionized water, heat and stir to dissolve, and prepare an acrylic acid solution with a mass concentration of 5%. Then add ammonium persulfate initiator, the amount of ammonium persulfate added is 3% of the mass of acrylic acid, stir evenly, and then immerse the plasma-treated polypropylene fiber in the above solution according to a bath ratio of 1:30. Keep the temperature at 70°C for 3 hours to react. The treated fiber is repeatedly washed with deionized water to remove the chemical reagents remaining on the surface, and placed in an oven to dry to constant weight to obtain modified polypropylene fiber.

[0080] Preparation of composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric:

[0081] A polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.5 μm and a thickness of 0.1 mm was selected and wiped with an ethanol cotton ball and dried with nitrogen. A high-count cotton fabric with a count of 120 was selected and desized by soaking in a 0.5% sodium hydroxide solution for 30 minutes, rinsed with clean water until neutral, and then dried at 80°C for 2 hours. A silicone adhesive was also applied, preheated in a 40°C water bath for 30 minutes and stirred until the viscosity reached 600 mPa·s. The PTFE microporous membrane was placed in a plasma treatment apparatus and treated at 150 W for 5 minutes to obtain a pretreated PTFE microporous membrane. Next, a 0.02 mm thick layer of adhesive was evenly applied to the surface of the pretreated membrane using a scraper at a 45° angle and a speed of 10 cm / s. The dried high-count cotton fabric was then placed on top and rolled twice with a rubber roller to remove air and form a tight bond. The membrane was then placed in a hot press apparatus and pressed at 150°C and 0.5 MPa for 5 minutes. The membrane was then cooled to obtain the final product.

[0082] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0083] The middle fabric was laid flat on a clean, dry and well-ventilated operating table, and a polyurethane adhesive with a viscosity of 600 mPa·s was evenly coated on both sides of the middle fabric. During the coating process, the thickness of the adhesive was controlled to 0.1 mm. Then, the pre-treated inner fabric was flatly superimposed on the middle fabric to ensure that the two were tightly fitted without wrinkles or offset. At the same time, the outer fabric was superimposed on the bottom of the middle fabric. Subsequently, the two were transferred to a laminating device for hot pressing. The hot pressing temperature was between 130°C, the pressure was controlled at 0.8 MPa, and the hot pressing time was controlled at 5 minutes. The product was then cooled.

[0084] Example 5

[0085] A moisture-permeable multi-layer composite fabric comprises an inner layer, a middle layer and an outer layer bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; the polypropylene non-woven fabric is prepared from modified polypropylene fiber by a needle-punching method.

[0086] The preparation method of modified polypropylene fiber comprises the following steps:

[0087] S1. Adding nano-montmorillonite to deionized water at a mass volume ratio of 1 g / 50 mL, stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding cetyltrimethylammonium bromide to the suspension at a mass ratio of nano-montmorillonite to cetyltrimethylammonium bromide of 1:0.3, continuing to stir evenly, then heating to 60° C., stirring for 7 hours, and centrifuging, washing, and drying to obtain modified nano-montmorillonite;

[0088] S2. Add the modified nano-montmorillonite to anhydrous ethanol at a mass volume ratio of 1 g / 20 mL, disperse evenly by ultrasonic oscillation, then add polypropylene resin, the mass ratio of the modified nano-montmorillonite to the polypropylene resin is 1:60, stir and mix evenly, remove the anhydrous ethanol by a rotary evaporator to obtain a mixed masterbatch, add the mixed masterbatch to a screw extruder for melt blending and granulation, control the extrusion temperature at 150° C., and the screw speed at 200 r / min to obtain a nano-montmorillonite masterbatch;

[0089] S3. Adding nano-montmorillonite masterbatch into the spinning barrel of a spinning machine, controlling the spinning temperature at 170° C., using a metering pump to accurately control the melt extrusion amount, spinning at a spinning speed of 1200 m / min to obtain spun fibers, stretching the spun fibers at a stretching ratio of 3.5 times and a stretching temperature of 90° C., and then performing a heat setting treatment at 120° C. to obtain montmorillonite-doped polypropylene fibers;

[0090] S4. Plasma-treating the montmorillonite-doped polypropylene fiber for 3 minutes using a low-temperature plasma device with a plasma treatment power controlled at 100 W to introduce more oxygen-containing hydrophilic groups onto the surface of the fiber, thereby obtaining plasma-treated polypropylene fiber.

[0091] S5. Add acrylic acid to deionized water, heat and stir to dissolve, and prepare an acrylic acid solution with a mass concentration of 5%. Then add ammonium persulfate initiator, the amount of ammonium persulfate added is 3% of the mass of acrylic acid, and stir evenly. Then, immerse the plasma-treated polypropylene fiber in the above solution according to a bath ratio of 1:30, and keep it warm at 65°C for 2 hours. The treated fiber is repeatedly washed with deionized water to remove the chemical reagents remaining on the surface, and placed in an oven to dry to constant weight to obtain modified polypropylene fiber.

[0092] Preparation of composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric:

[0093] A polytetrafluoroethylene (PTFE) microporous membrane with a pore size of 0.1 μm and a thickness of 0.05 mm was selected and wiped with an ethanol cotton ball and blown dry with nitrogen. A high-count cotton fabric with a count of 120 was selected and desized by soaking in a 0.5% sodium hydroxide solution for 30 minutes, rinsed with clean water until neutral, and then dried at 80°C for 2 hours. A silicone adhesive was also applied, preheated in a 40°C water bath for 30 minutes and stirred until the viscosity reached 600 mPa·s. The PTFE microporous membrane was placed in a plasma treatment apparatus and treated at 150 W for 5 minutes to obtain a pretreated PTFE microporous membrane. Next, a 0.02 mm thick layer of adhesive was evenly applied to the surface of the pretreated membrane using a scraper at a 45° angle and a speed of 10 cm / s. The dried high-count cotton fabric was then placed on top and rolled twice with a rubber roller to remove air and form a tight fit. Then, put it into the hot pressing equipment, hot press it at 150°C and 0.5MPa for 5 minutes, and cool it to obtain the product.

[0094] A method for preparing a moisture-permeable multi-layer composite fabric comprises the following steps:

[0095] The middle fabric was laid flat on a clean, dry and well-ventilated operating table, and a polyurethane adhesive with a viscosity of 600 mPa·s was evenly coated on both sides of the middle fabric. During the coating process, the thickness of the adhesive was controlled to 0.1 mm. Then, the pre-treated inner fabric was flatly superimposed on the middle fabric to ensure that the two were tightly fitted without wrinkles or offset. At the same time, the outer fabric was superimposed on the bottom of the middle fabric. Subsequently, the two were transferred to a laminating device for hot pressing. The hot pressing temperature was between 130°C, the pressure was controlled at 0.8 MPa, and the hot pressing time was controlled at 5 minutes. The product was then cooled.

[0096] Comparative Example 1

[0097] The difference between Comparative Example 1 and Example 1 is:

[0098] Replace modified polypropylene fiber with regular polypropylene fiber;

[0099] The remaining steps are the same as those in Example 1.

[0100] Comparative Example 2

[0101] The difference between Comparative Example 2 and Example 1 is:

[0102] Step S1 is omitted in the preparation process of modified polypropylene fiber.

[0103] Replace the modified nano-montmorillonite with ordinary nano-montmorillonite,

[0104] The remaining steps are the same as those in Example 1.

[0105] Comparative Example 3

[0106] The difference between Comparative Example 3 and Example 5 is:

[0107] In step S1 of the modified polypropylene fiber preparation process,

[0108] The mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is 1:0.2.

[0109] The remaining steps are the same as those in Example 1.

[0110] Comparative Example 4

[0111] The difference between Comparative Example 4 and Example 4 is:

[0112] In step S1 of the modified polypropylene fiber preparation process,

[0113] The mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is 1:0.6.

[0114] The remaining steps are the same as those in Example 4.

[0115] Comparative Example 5

[0116] The difference between Comparative Example 5 and Example 4 is:

[0117] In step S1 of the modified polypropylene fiber preparation process,

[0118] The mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is 1:0.7.

[0119] The remaining steps are the same as those in Example 4.

[0120] Performance testing:

[0121] 1. Mechanical strength test of the middle layer polypropylene non-woven fabric: Cut a 200mm long and 50mm wide sample from the middle layer polypropylene non-woven fabric of each embodiment and comparative example, and prepare 5 samples of each type in parallel. Use an electronic universal material testing machine with an accuracy of ±0.5%, set the tensile speed to 50mm / min and the initial clamping distance to 100mm. Clamp the sample vertically between the upper and lower clamps, ensuring that the center lines coincide, start the testing machine and stretch it until it breaks, and record the maximum load value. The tensile strength is obtained by dividing the maximum load value by the width and thickness of the sample. Measure the thickness of the sample at 5 locations and take the average value. Finally, calculate the average tensile strength of the 5 samples of each sample as the test result.

[0122] 2. Composite fabric moisture permeability (water vapor permeability) test: Circular specimens with a diameter of 70 mm were cut from the composite fabrics of each embodiment and comparative example, and three specimens of each type were prepared in parallel. A moisture permeability cup method test apparatus was used, comprising a moisture permeability cup with an inner diameter of 65 mm and a depth of 25 mm, and a constant temperature and humidity chamber capable of controlling the temperature at (38±2)°C and the humidity at (90±5)%. Distilled water was filled into the moisture permeability cup to a depth of approximately 3 mm from the cup opening, and the specimen was tightly secured to the cup opening with sealant. The moisture permeability cup was placed in the constant temperature and humidity chamber for 24 hours. The initial mass m1 before placement and the mass m2 after 24 hours were weighed using an electronic balance with an accuracy of 0.001 g. The moisture permeability was calculated using the formula (m2-m1) / sample area × 24. The average moisture permeability of the three specimens for each sample was calculated as the test result.

[0123] 3. Test of air permeability (air permeability) of composite fabrics: Cut circular specimens with a diameter of 75 mm from the composite fabrics of each embodiment and comparative example, and prepare 5 specimens of each type in parallel. Use an air permeability meter with a test pressure difference range of 0-2000 Pa and an accuracy of ±2%, and set the test pressure difference to 100 Pa. Install the specimen flatly on the test hole of the air permeability meter to ensure that there are no wrinkles and that the seal is good. Start the air permeability meter and record the air flow rate per unit time through the unit area of ​​the specimen under the set pressure difference. Change the flow rate unit from L / (m 2 ·s) is converted to mm / s, and the average air permeability of 5 specimens of each sample is calculated as the test result.

[0124]

[0125]

[0126] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A moisture permeable multi-layer composite fabric, characterized in that: It comprises an inner layer, a middle layer and an outer layer which are bonded and stacked in sequence, wherein the inner layer is a bamboo fiber fabric, the middle layer is a polypropylene non-woven fabric, and the outer layer is a composite layer of a polytetrafluoroethylene microporous membrane and a high-count cotton fiber fabric; The polypropylene non-woven fabric is prepared from modified polypropylene fiber, and the preparation method of the modified polypropylene fiber comprises the following steps: S1. Adding nano-montmorillonite to deionized water and stirring to preliminarily disperse the nano-montmorillonite in the water to form a suspension, adding hexadecyltrimethylammonium bromide to the suspension, continuing to stir evenly, then heating to 60° C. and stirring for 7 hours, followed by centrifugation, washing, and drying to obtain modified nano-montmorillonite; S2, adding the modified nano-montmorillonite to anhydrous ethanol, uniformly dispersing it by ultrasonic oscillation, then adding polypropylene resin, stirring and mixing uniformly, removing the anhydrous ethanol by rotary evaporator to obtain a mixed masterbatch, adding the mixed masterbatch to a screw extruder for melt blending and granulation to obtain nano-montmorillonite masterbatch; S3, adding nano-montmorillonite masterbatch into the spinning machine barrel, using a metering pump to accurately control the melt extrusion amount, spinning at a spinning speed of 1200-1800 m / min to obtain spun fibers, stretching the spun fibers, and then performing heat setting treatment to obtain montmorillonite-doped polypropylene fibers; S4. Plasma-treating the montmorillonite-doped polypropylene fiber using a low-temperature plasma device to introduce more oxygen-containing hydrophilic groups onto the surface of the montmorillonite-doped polypropylene fiber to obtain plasma-treated polypropylene fiber; S5. Add acrylic acid to deionized water, heat and stir to dissolve, to obtain an acrylic acid solution, then add ammonium persulfate initiator, stir evenly, then add plasma-treated polypropylene fiber to soak, keep warm for reaction, repeatedly wash the treated fiber with deionized water to remove residual chemical reagents on the surface, and place in an oven to dry to constant weight to obtain modified polypropylene fiber; The preparation method of the composite layer of polytetrafluoroethylene microporous membrane and high-count cotton fiber fabric comprises the following steps: The polytetrafluoroethylene microporous membrane is subjected to plasma treatment to increase its surface activity to obtain a pretreated polytetrafluoroethylene microporous membrane, an adhesive is coated on the surface of the pretreated polytetrafluoroethylene microporous membrane, a high-count cotton fiber fabric is covered on the pretreated polytetrafluoroethylene microporous membrane to make the two closely fit together, and hot pressing is performed to shape the membrane, and the membrane is cooled to obtain the membrane.

2. The moisture-permeable multi-layer composite fabric according to claim 1, characterized in that: In the step S1, the mass ratio of nano-montmorillonite to hexadecyltrimethylammonium bromide is 1:0.3-0.

5.

3. The moisture-permeable multi-layer composite fabric according to claim 1, characterized in that: In step S3, the spinning temperature is controlled at 170-180°C.

4. The moisture-permeable multi-layer composite fabric according to claim 1, characterized in that: In step S5, the reaction temperature is kept at 65-70° C. for 2-3 hours.

5. The moisture-permeable multi-layer composite fabric according to claim 1, characterized in that: The pore size of the polytetrafluoroethylene microporous membrane is 0.1-0.5 μm, and the thickness is 0.05-0.1 mm.

6. A method for preparing a moisture-permeable multi-layer composite fabric according to any one of claims 1 to 5, characterized in that: The following steps are involved: The adhesive is applied to both sides of the middle layer, and then the inner layer and the outer layer are respectively stacked on the upper and lower sides of the middle layer, and then placed in a laminating device for heat pressing treatment, and after cooling, the product is obtained.

7. The method for preparing a moisture-permeable multi-layer composite fabric according to claim 6, characterized in that: The adhesive is a polyurethane adhesive.

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