Waterproof breathable material, fabric and preparation method

Abstract

The invention relates to the technical field of high polymer materials and functional textile fabrics, in particular to a waterproof breathable material, a fabric and a preparation method. The waterproof breathable material is formed by UV curing of a coating solution containing components such as a thermo-sensitive N-tert-butyl acrylamide-acrylamide copolymer, TEMPO oxidized nano cellulose, a hydrophobic finishing agent perfluorooctyltriethoxysilane and the like. The molar ratio of copolymer monomers is controlled to be (2.5-3.5): 1, and the low critical solution temperature (LCST) of the material is regulated and controlled to be 15-20 DEG C, so that the fabric has the intelligent response characteristics of low-temperature low breathability and high-temperature high breathability and meets the comfort requirement of a human body. Meanwhile, TOCNF is anchored to the fiber surface of the fabric base layer through covalent bonds and serves as a firm middle layer, and the interface bonding force and durability of the functional layer and the base material are greatly improved. The prepared fabric is remarkable in intelligent response and excellent in washing durability, and can be widely applied to the fields of outdoor clothes, medical protection and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials and functional textile fabrics, and particularly relates to a waterproof and breathable material, a fabric and a preparation method. BACKGROUND

[0002] Waterproof and breathable fabric is an important branch of functional textile materials, and is widely used in outdoor clothing, protective equipment and medical textiles. Its traditional technical route mainly includes two categories: one is to block liquid water while allowing water vapor molecules to pass through by using microporous membranes (such as ePTFE and PU membranes); the other is to realize the adsorption-transport-desorption of water molecules by using hydrophilic non-porous membranes (such as TPU) through the hydrophilic groups of the polymer chain. However, the breathability of these traditional fabrics is usually static, and cannot be dynamically adjusted according to the external environment or the state of the human body.

[0003] To realize dynamic adjustment, intelligent responsive materials are introduced into the field of textiles. Among them, temperature-sensitive polymers have become a research hotspot because they can respond to changes in environmental temperature and change their swelling state and chain segment fluidity. For example, the Chinese invention patent with the document number CN101302718B discloses a preparation method of a temperature-sensitive intelligent anti-immersion fabric and its product. The technical solution applies a dry hydrogel coating layer of temperature-sensitive N-tert-butyl acrylamide and acrylamide copolymer on the anti-immersion fabric, which is breathable and moisture-permeable in normal environment, and quickly seals water after encountering water, thereby improving the anti-immersion performance of the material. At the same time, it has temperature-sensitive intelligence, automatically adjusts the water and moisture permeability according to the environmental temperature, enhances the waterproof performance of the clothing, solves the problem of insufficient water and moisture permeability of B-type anti-immersion fabric, realizes efficient waterproof performance and temperature-sensitive adjustment, and improves the waterproof performance and comfort of the clothing.

[0004] However, the adjustment mode of such fabric disclosed by CN101302718B is exactly opposite to the comfort demand of the human body in real environment. In normal wearing scenarios, the human body needs the fabric to be windproof and warm in low temperature environment to reduce heat loss, at which time the fabric should have low air permeability; when it is high temperature or motion sweating, the fabric needs to be quickly moisture-permeable and breathable to keep dry, at which time the fabric should have high air permeability. The existing PNIPAM-based fabric cannot meet the functional demand of "low temperature windproof and high temperature air permeability". In addition, the existing temperature-sensitive intelligent fabric also faces another big technical bottleneck: poor interface bonding strength. The temperature-sensitive polymer layer is mainly combined with the textile substrate by physical coating. In the repeated swelling-shrinking cycle or washing process, the waterproof and breathable material is easy to fall off and powder, which leads to rapid decay of intelligent function and serious lack of durability.

[0005] Therefore, there is an urgent need in the art for a new type of intelligent fabric that not only realizes the function reversal of "low-temperature windproof and high-temperature breathable" in line with human comfort needs, but also must have a strong interface combination to ensure the long-term stability of the intelligent adjustment function. SUMMARY

[0006] To solve the above technical problems, the purpose of the present application is to provide a waterproof and breathable material, a fabric and a preparation method, aiming to provide a high molecular material and its application in functional textile fabric, which has excellent intelligent adjustment function, high hydrostatic pressure resistance and high durability, realizing a good balance of waterproofness, breathability, comfort and durability.

[0007] To achieve the above technical effects, the present application adopts the following technical solutions: In a first aspect, the purpose of the present application is to provide a waterproof and breathable material formed by a coating liquid of the following components, in terms of mass fraction: Temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer: 80-120 parts; Crosslinking monomer N, N'-methylene bisacrylamide: 3-10 parts; Photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone: 5-15 parts; TEMPO oxidized nanocellulose: 20-40 parts; Hydrophobic finishing agent perfluorooctyl triethoxysilane: 5-15 parts; and solvent deionized water: 1000 parts.

[0008] As a preferred technical solution, in the temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer, the molar ratio of N-tert-butyl acrylamide to acrylamide is (2.5~3.5):1.

[0009] As a preferred technical solution, the low critical solution temperature of the waterproof and breathable material is regulated within the range of 15-20℃.

[0010] In a second aspect, the present application further provides a waterproof and breathable fabric, which comprises a base layer and a functional layer compounded on the surface of the base layer; the functional layer is formed by coating and curing the waterproof and breathable material.

[0011] As a preferred technical solution, the base layer is a cellulose fiber fabric, and the fiber surface is covalently anchored with TEMPO oxidized nanocellulose through a silane coupling agent and a chemical crosslinking agent.

[0012] As a preferred technical solution, the silane coupling agent is gamma-aminopropyl triethoxysilane.

[0013] As a preferred technical solution, the chemical crosslinking agent is a mixture of EDC and NHS.

[0014] In a third aspect, the present application further provides a preparation method of the waterproof and breathable fabric, comprising the following steps: (1) base layer selection: selecting a fiber fabric as the base fabric; (2) plasma treatment: treating the base fabric with plasma under a power of 700-900 W; (3) silanization treatment: immersing the base fabric treated with plasma in a silane coupling agent aqueous solution with a mass concentration of 1-3%, adopting a double-dipping and double-rolling process with a rolling rate of 70-80%, and then drying to obtain the base fabric treated in step (3); (4) TOCNF anchoring: immersing the base fabric treated in step (3) in a TEMPO oxidized nanocellulose aqueous dispersion activated by EDC and NHS, reacting at 40-60°C for 1-2 hours, washing with ultrasonic hot water after the reaction is completed, and drying to obtain the fabric after TOCNF anchoring; (5) coating liquid preparation: weighing and mixing components of the coating liquid to obtain the coating liquid; (6) coating and pre-drying: coating the coating liquid on the surface of the fabric after TOCNF anchoring and pre-drying; (7) UV curing: irradiating and curing under ultraviolet light at a temperature lower than 35°C to obtain the cured fabric; (8) post-treatment: washing the cured fabric and finally drying.

[0015] As a preferred technical solution, the preparation method of the waterproof and breathable fabric comprises the following steps: (1) base layer selection: selecting a fiber fabric as the base fabric; the fiber fabric is at least one of cotton, hemp, and viscose fiber; (2) plasma treatment: treating the base fabric with plasma under a power of 700-900 W (for example, plasma treatment for 1-3 minutes); (3) silanization treatment: immersing the base fabric treated with plasma in a silane coupling agent aqueous solution with a mass concentration of 1-3%, adopting a double-dipping and double-rolling process with a rolling rate of 70-80%, and then drying (for example, drying at 80-100°C for 20-30 minutes); (4) TOCNF anchoring: immersing the base fabric obtained in step (3) in a TEMPO oxidized nanocellulose aqueous dispersion activated by EDC and NHS, reacting at 40-60°C for 1-2 hours, washing with ultrasonic hot water after the reaction is completed, and drying; (5) Coating liquid preparation: each component is weighed according to the above proportion, mixed, and the coating liquid is prepared; (6) Coating and pre-drying: the coating liquid is coated on the surface of the treated fabric, and pre-drying (for example, pre-drying at 70-90℃ for 3-5 minutes); (7) UV curing: under the condition that the temperature is lower than 35℃, ultraviolet light irradiation (for example, using ultraviolet light with a wavelength of 395nm for 2-4 minutes); (8) Post-treatment: washing the cured fabric (for example, washing in warm water at 40-60℃); and finally drying.

[0016] As a preferred technical solution, in step (4), the molar ratio of EDC to NHS is 2:1, and the amount of EDC added is 1.0-1.5 times the molar amount of carboxyl groups in TOCNF.

[0017] As a preferred technical solution, the temperature of drying in step (8) is 60-80℃.

[0018] Compared with the prior art, the application has the following beneficial effects: Firstly, by accurately controlling the molar ratio of N-tert-butyl acrylamide to acrylamide in the temperature-sensitive copolymer to be (2.5-3.5), the low critical solution temperature (LCST) of the material is successfully reduced from the traditional PNIPAM of about 32℃ to the room temperature interval of 15-20℃, which makes the fabric in a low temperature (lower than LCST, such as 15℃) environment, the polymer chain swells, the pore size decreases, and the air permeability decreases, which is beneficial to windproof and warm-keeping; in a high temperature (higher than LCST, such as 25℃) environment, the polymer chain shrinks, the pore size increases, and the air permeability significantly improves, which is beneficial to heat dissipation and moisture removal.

[0019] Meanwhile, the application innovatively introduces TEMPO oxidized nanocellulose (TOCNF) anchored by covalent bond as a "molecular bridge" between the base layer and the functional layer. Through plasma activation, silanization pretreatment, and the use of EDC / NHS chemical crosslinking agent, the TOCNF is combined with the fiber base layer through a firm covalent bond, and its large specific surface area and rich hydroxyl groups can form strong physical entanglement and hydrogen bond with the upper functional layer. This multi-level interface strengthening design effectively prevents the functional layer from falling off and pulverizing during use and washing, so that the hydrostatic pressure and water vapor permeability retention rate of the fabric can be maintained at more than 95% after 50 times of accelerated washing, realizing the long-term stability of the intelligent function.

[0020] In addition, the TEMPO-oxidized nanocellulose (TOCNF) in the coating liquid provided by the application not only enhances the interfacial bonding force, but also forms a three-dimensional network structure in the cured coating, thereby playing a role of enhancing and toughening; the hydrophobic finishing agent perfluorooctyltriethoxysilane endows the coating with durable waterproof performance. These components synergize with the temperature-sensitive polymer network, so that the final fabric not only has excellent intelligent adjustment function, but also has high hydrostatic pressure resistance and high durability, thereby realizing a good balance among waterproofness, air permeability, comfort and durability.

[0021] In summary, the application mainly uses water as a solvent, and adopts UV photocuring technology for coating curing, so that energy consumption is low and the environment is friendly. The whole process flow is reasonably designed, the parameter control is clear, the compatibility with existing textile dyeing and finishing equipment is good, and it is very suitable for industrial large-scale production. DETAILED DESCRIPTION

[0022] The following examples are only used to more clearly illustrate the technical solutions of the application, and therefore only serve as examples, but cannot be used to limit the protection scope of the application.

[0023] Those skilled in the art should understand that the application can also be implemented without certain specific details. In some other embodiments, methods, means, apparatus and steps familiar to those skilled in the art are not described in detail, in order to highlight the main idea of the application. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as generally understood by those skilled in the art. Unless otherwise specified, the units used in the specification are international standard units, and the numerical values and numerical value ranges appearing in the application should be understood to include the systematic errors inevitable in industrial production.

[0024] Unless otherwise specified, the experimental methods used in the following examples are conventional methods; the materials, reagents or instruments used are not marked with the manufacturer, and are reagents and materials that can be obtained through commercial channels; the specific conditions are not marked in the examples, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. At the same time, the application does not limit the source of the raw materials used, and the raw materials used in the application are ordinary commercially available products in the technical field, unless otherwise specified. Unless otherwise specified, the "ratio" referred to in the following examples is the ratio of mass parts.

[0025] Unless otherwise specified, the base layer used in the examples is a cellulose fiber fabric (such as cotton fabric), and the fiber surface is covalently bonded to TEMPO-oxidized nanocellulose (TOCNF) through silane coupling agent (γ-aminopropyltriethoxysilane) and chemical crosslinking agent (EDC / NHS mixture).

[0026] Example 1 The purpose of the present embodiment is to prepare a waterproof and breathable material and its fabric, as follows: First, the present embodiment provides a waterproof and breathable material preparation method as follows: According to the mass fraction, 100 parts of temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer (the molar ratio of N-tert-butyl acrylamide to acrylamide is 3:1), 6.5 parts of crosslinking monomer N, N'-methylenebisacrylamide (CAS number: 110-26-9, purchased from Sigma Aldrich (Shanghai) Trading Co., Ltd.), 10 parts of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 30 parts of TEMPO oxidized nanocellulose (purchased from Nanjing Tianlu Nanometer Technology Co., Ltd.), and 10 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane are mixed with 1000 parts of deionized water to form a coating liquid. The coating liquid can form a waterproof and breathable material after photocuring. The low critical solution temperature (LCST) of the waterproof and breathable material formed by the coating liquid is regulated to 17℃. At the same time, the waterproof and breathable material formed by the coating liquid is recorded as A1.

[0027] Specifically, in the preparation process of the waterproof and breathable material, the temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer is synthesized as follows: Prepare the reactor and solvent: add 100g of deionized water as a solvent to a three-necked flask and continuously pass nitrogen for 30 minutes.

[0028] Prepare the mixed monomer aqueous solution: dissolve N-tert-butyl acrylamide (NTBAAm, 12.91g, 0.1mol) and acrylamide (AAm, 2.37g, 0.033mol) in 50g of deionized water to prepare a mixed monomer aqueous solution of NTBAAm and AAm (the molar ratio of NTBAAm to AAm is 3:1 at this time), and transfer the solution to a constant pressure dropping funnel for standby.

[0029] Initialize the reaction system: add 1.0 wt% of initiator azobisdimethylaminoformamide hydrochloride (AIBA, 0.153g) based on the total mass of NTBAAm and AAm to the three-necked flask mentioned above which has been purged with nitrogen and contains the solvent, and stir to dissolve it in water to obtain the reaction system.

[0030] Polymerization reaction: under continuous nitrogen protection and stirring, the reaction system is heated to 70℃ and kept at constant temperature. Then, the prepared mixed monomer aqueous solution is slowly added to the reaction system through a constant pressure dropping funnel, and the dropping time is controlled to be about 1 hour.

[0031] Incubate and mature: after the addition is completed, continue to stir at 70℃ for 5 hours to make the polymerization reaction proceed fully.

[0032] After the reaction is completed, the obtained reaction solution is poured into a large amount (about 500 mL) of acetone to settle, and after the polymer is precipitated, the white precipitate is collected by filtration and washed with acetone three times to remove unreacted monomers and impurities. Finally, the product is placed in a vacuum drying oven at 50°C and dried for 24 hours to obtain a white solid of the temperature-sensitive copolymer.

[0033] Based on the foregoing waterproof and breathable material, the application further provides a waterproof and breathable fabric, a preparation method of the waterproof and breathable fabric, and the like. Base layer selection: cotton fabric is selected as the base fabric; Plasma treatment: the base fabric is placed in a low-temperature plasma treatment device, and air is introduced as the treatment atmosphere. Under the conditions of a gas pressure of 30 Pa and a power of 800 W, the fabric is treated for 2 minutes to improve the surface activity and roughness of the fabric, introduce polar groups, and enhance the bonding force with the subsequent treatment layer. Silanization treatment: the base fabric treated by plasma is immersed in a 2% mass concentration γ-aminopropyl triethoxysilane ethanol aqueous solution (the volume ratio of ethanol to water is 1:4) to perform a two-dip-two-press process (i.e., dipping, pressing, re-dipping, and re-pressing) to control the pick-up rate (liquid absorption rate) to 78% and ensure that the silane coupling agent is uniformly introduced into the fabric. Subsequently, the base fabric is dried at 80°C for 5 minutes to remove most of the solvent, and then baked at 100°C for 2 minutes to fully complete the condensation reaction and form a firm silanization layer, thereby obtaining the silanized fabric. TOCNF anchoring: a. Configuration of TOCNF dispersion: TEMPO-oxidized nanocellulose (TOCNF, with a carboxyl content of 1.2 mmol / g measured by conductometric titration) is weighed and configured into a water dispersion with a concentration of 0.5 wt%.

[0034] b. Carboxyl activation: according to the volume, concentration, and carboxyl content of the prepared dispersion, the total molar amount of carboxyl groups in the dispersion is calculated. Based on this, the amount of EDC added is 1.2 times the total molar amount of carboxyl groups, and the molar ratio of EDC to NHS is 2:1. The chemical cross-linking agents EDC and NHS are accurately weighed and added to the TOCNF water dispersion. Stir at room temperature for 15 minutes to activate the carboxyl groups on the surface of TOCNF to form active esters, which are easy to react with amine groups, thereby obtaining the activated TOCNF dispersion.

[0035] c. Covalent grafting: the silanized fabric is immersed in the above-activated TOCNF dispersion and oscillated in a 50°C water bath environment for 1.5 hours to allow the carboxyl groups of the activated TOCNF to covalently bond with the amine groups exposed on the surface of the silane layer of the fabric, thereby achieving firm anchoring of the TOCNF on the surface of the fiber.

[0036] d. Post-washing: After the completion of step c, the fabric was removed and washed with hot water assisted by ultrasonic to remove the physically adsorbed TOCNF. Finally, it was dried at 80°C for 30 minutes to obtain the base fabric with TOCNF anchored on the surface (TOCNF-anchored fabric).

[0037] Coating liquid preparation: According to the above method for preparing a waterproof and breathable material, the temperature-sensitive copolymer, cross-linking monomer, photoinitiator, TOCNF, hydrophobic finishing agent, and deionized water were accurately weighed and mixed to form a stable coating liquid after thorough stirring. Coating and pre-drying: a. Coating: The prepared coating liquid was uniformly coated on the surface of the silanized fabric. The wet coating amount was accurately controlled at 120 grams per square meter (g / m²) during the coating process.

[0038] b. Pre-drying: The coated fabric was immediately transferred to a forced air oven and pre-dried at 80°C for 4 minutes. This step aimed to remove most of the water, allowing the coating to form a preliminary film and avoiding the formation of bubbles or affecting the curing effect during subsequent UV curing due to excessive water.

[0039] UV curing: The pre-dried fabric was placed in a UV curing device under room temperature conditions, and irradiated with ultraviolet light of wavelength 395 nm for 3 minutes to cause the monomers and polymers in the coating liquid to undergo photopolymerization, forming a three-dimensional network structure and completing the curing of the functional layer. Post-processing: The UV-cured fabric was immersed in warm water at 50°C and gently stirred to remove unreacted monomers, oligomers, and residual additives. Finally, it was dried at 80°C to obtain the final waterproof and breathable intelligent fabric (recorded as A2). The functional layer of the fabric was firmly combined with the base layer, and had excellent waterproofness, controllable breathability, and washing resistance.

[0040] The obtained fabric had excellent waterproofness and breathability, and the interface was firmly combined. The waterproof and breathable fabric prepared by this method was recorded as A2.

[0041] Example 2 Please refer to Example 1. This example is similar to Example 1, and mainly adjusts the process parameters to prepare a waterproof and breathable material and its fabric. Specifically: The coating liquid formula provided by the embodiment is: 90 parts of temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer (molar ratio of N-tert-butyl acrylamide to acrylamide is 3:1), 5 parts of crosslinking monomer N, N'-methylenebisacrylamide, 12 parts of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 8 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane, and 1000 parts of deionized water as a solvent; the LCST of the material prepared by using the coating liquid is 16°C.

[0042] The temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer is synthesized according to the steps in Embodiment 1, but the monomer feeding ratio is adjusted to be N-tert-butyl acrylamide (13.55 g, 0.105 mol) and acrylamide (2.25 g, 0.031 mol), so that the molar ratio is 3.4:1. The amount of initiator AIBA is 1.2 wt% (0.190 g) of the total mass of the monomers, the reaction temperature is controlled at 65°C, and the reaction time is extended to 6.5 hours.

[0043] The preparation method of the waterproof and breathable fabric provided by the embodiment is basically the same as that in Embodiment 1, but the parameters are adjusted as follows: (2) plasma treatment: air is introduced as the treatment atmosphere, the gas pressure is controlled at 30 Pa, the power is 750 W, and the treatment time is 2.5 minutes; (3) silanization treatment: the fabric after plasma treatment is immersed in a γ-aminopropyltriethoxysilane ethanol aqueous solution (volume ratio of ethanol to water is 1:4) with a mass concentration of 1.5%, the pick-up rate is controlled at 78%, and in the drying process, the base fabric is first dried at 80°C for 5 minutes to remove most of the solvent, and then baked at 100°C for 2 minutes to fully complete the condensation reaction and form a firm silanization layer, thereby obtaining the silanized fabric; (4) TOCNF anchoring: the reaction temperature is 45°C, the time is 1.8 hours, and the amount of EDC added is 1.1 times the molar amount of the carboxyl group of TOCNF; (6) coating and pre-drying: the pre-drying temperature is 75°C, and the time is 4.5 minutes; (7) UV curing: the temperature is 32°C, and the ultraviolet light irradiation time is 2.5 minutes; (8) post-treatment: washing temperature is 45°C, and drying temperature is 75°C.

[0044] Embodiment 3 Please refer to Embodiment 1. This embodiment is similar to Embodiment 1, and mainly adjusts the process parameters to prepare a waterproof and breathable material and its fabric. Specifically: The coating liquid formula provided by the embodiment is: 110 parts of temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer (molar ratio of N-tert-butyl acrylamide to acrylamide 3:1), 8 parts of crosslinking monomer N,N'-methylenebisacrylamide, 8 parts of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone, 35 parts of TOCNF, 12 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane, and 1000 parts of solvent deionized water.

[0045] The LCST of the material prepared by using the coating liquid is 18°C.

[0046] The temperature-sensitive N-tert-butyl acrylamide-acrylamide copolymer is synthesized according to the same steps as in Embodiment 1, but the monomer feeding ratio is adjusted to be N-tert-butyl acrylamide (12.28 g, 0.095 mol) and acrylamide (2.49 g, 0.035 mol), so that the molar ratio is 2.7:1. The amount of initiator AIBA is 0.8 wt% (0.118 g) of the total mass of monomers, the reaction temperature is increased to 75°C, and the reaction time is shortened to 5.5 hours.

[0047] The preparation method of the waterproof and breathable fabric provided by the embodiment is basically the same as that of Embodiment 1, but the parameters are adjusted as follows: (2) plasma treatment: air is introduced as the treatment atmosphere, the gas pressure is controlled to be 30 Pa, the power is 850 W, and the treatment time is 1.5 minutes; (3) silanization treatment: the fabric treated by plasma is immersed in a γ-aminopropyltriethoxysilane ethanol aqueous solution (volume ratio of ethanol to water is 1:4) with a mass concentration of 2.5%, the pick-up rate is controlled to be 72%, and in the drying process, the base fabric is first dried at 80°C for 5 minutes to remove most of the solvent, and then baked at 100°C for 2 minutes to fully complete the condensation reaction and form a firm silanization layer, thereby obtaining the silanized fabric; (4) TOCNF anchoring: the reaction temperature is 55°C, the time is 1.2 hours, and the amount of EDC added is 1.4 times the molar amount of the carboxyl group of TOCNF; (6) coating and pre-drying: the pre-drying temperature is 85°C, and the time is 3.5 minutes; (7) UV curing: the temperature is 28°C, and the ultraviolet light irradiation time is 3.5 minutes; (8) post-treatment: the washing temperature is 55°C, and the drying temperature is 78°C.

[0048] Comparative Example 1 The purpose of the present comparative example is to synthesize temperature-sensitive copolymers by setting a series of gradient changes in the molar ratio, and accurately measure the LCST and the air permeability at the key temperature points (15°C, 25°C), in order to prove the influence of the molar ratio of NTBAAm to AAm on the function of the fabric. The preparation process of the fabric is kept completely consistent with Embodiment 1, and only the monomer feeding molar ratio in the synthesis of the temperature-sensitive copolymer is systematically changed, thereby preparing waterproof and breathable materials and waterproof and breathable fabrics.

[0049] Experimental results: The LCST of each waterproof and breathable material was accurately determined by differential scanning calorimetry (DSC), and the water vapor transmission rate (WVTR, g / m2·24h) of the waterproof and breathable fabric prepared by using the waterproof and breathable material was tested at 15°C and 25°C.

[0050] The experimental results of each group of Comparative Example 1 and Example 1 are shown in Table 1.

[0051] Table 1 Experimental results of each group of Comparative Example 1 and Example 1

[0052] The above experimental results show that as the proportion of hydrophobic component NTBAAm increases, the LCST of the copolymer gradually decreases from 26.3°C of Comparative Example 1-1 to 11.3°C of Comparative Example 1-6. However, the value of LCST itself is not the only key, but the dynamic change mode of water vapor transmission rate (WVTR) caused by its position relative to the ambient temperature is the core of solving the technical problems of the present application. The data show that when the molar ratio is less than 2.5:1 (such as Comparative Examples 1-1 and 1-2), the LCST is too high (> 24°C), and the WVTR of the fabric increases slowly during the temperature rise from 10°C to 20°C, and the main increase in breathability occurs after 20°C, which cannot realize effective intelligent adjustment in the normal temperature range. It is particularly important that the traditional PNIPAM material (Comparative Example 1-7) has a LCST (31.8°C) much higher than the test temperature range, showing a completely opposite "smart" mode, i.e. the breathability decreases when the temperature rises (30°C WVTR decreases by 20.51% compared with 20°C).

[0053] When the molar ratio of NTBAAm to AAm is controlled between 2.5:1 and 3.5:1, the LCST can be accurately set in the range of 13.2°C to 19.6°C, so that the breathability mutation point of the fabric falls into the actual wearing environment of 10-30°C, as shown in Example 1 (molar ratio 3.0:1, LCST=17.2°C). The WVTR remains at a low level (2855 g / m2·24h) at low temperature (10°C), which is beneficial to windproof and warm-keeping; when the temperature rises to 20°C (above LCST), the WVTR increases significantly (change rate +51.17%), which shows obvious phase change behavior; when the temperature further rises to 30°C, the WVTR continues to increase to 5983 g / m2·24h, which ensures the heat dissipation demand at high temperature. This "low temperature and low breathability, high temperature and high breathability" mode completely meets the physiological comfort demand of human body.

[0054] When the molar ratio of NTBAAm to AAm exceeds 3.5:1 (such as Comparative Examples 1-4), although the change rate from 20°C to 10°C is extremely high, the WVTR value at 30°C is slightly lower than that at 20°C, indicating that too low LCST leads to too drastic and early completion of the phase transition process, which may reach the air permeability limit at room temperature, thereby affecting the linear growth of performance, and the low-temperature basic WVTR is too low (Comparative Example 1-6 is only 1813), affecting daily comfort. When the molar ratio is 2.5:1 (Comparative Example 1-3), the WVTR change rate from 30°C to 20°C is only 4.66%, indicating that the high air permeability growth driven by phase transition has almost ended, and the amplitude of intelligent adjustment is limited. Therefore, the molar ratio of Example 1 (3.0:1) achieves the best balance among basic windproofness, high-temperature air permeability, and intelligent response amplitude.

[0055] Comparative Example 2 The purpose of this comparative example is to observe the effect of “plasma treatment” and “TOCNF covalent anchoring” on the durability of waterproof and breathable fabrics, specifically: The interface treatment methods of each group of Comparative Example 2 and Example 1 are shown in Table 2.

[0056] Table 2 Interface treatment methods of each group of Comparative Example 2 and Example 1

[0057] The waterproof and breathable fabrics prepared in each of the above comparative examples were tested, including: Washing durability: accelerated washing test was carried out according to AATCC 61-2020 2A standard to simulate 50 times of home washing.

[0058] Performance test: the hydrostatic pressure (referring to GB / T 4744-2013) and 25°C water vapor transmission rate (WVTR) of the fabric before and after washing were tested respectively, and the retention rate was calculated.

[0059] The experimental results of each group of Comparative Example 2 and Example 1 are shown in Table 3.

[0060] Table 3 Experimental results of each group of Comparative Example 2 and Example 1

[0061] The experimental results show that: The comparative example 2-1 without reinforcement treatment has the worst bonding force, and the functional layer is seriously peeled off after 50 times of washing, the hydrostatic pressure retention rate is only 29.4%, the WVTR retention rate is reduced to 35.1%, and the performance retention rate is extremely low. Only the plasma treatment (comparative example 2-2) increases the specific surface area by physical etching, the bonding force is improved, the hydrostatic pressure retention rate is increased to 42.9%, and the WVTR retention rate is 47.9%. After introducing the silanization treatment (comparative example 2-3), the durability is significantly improved through chemical bonding, the hydrostatic pressure retention rate and the WVTR retention rate are obviously improved, and the complete treatment (including TOCNF anchoring) adopted in the example 1 brings a qualitative leap, the hydrostatic pressure retention rate is 96.0%, and the WVTR retention rate is 97.9%. This proves that the TOCNF as a "molecular bridge" forms a firm covalent bond and a physical entanglement network with the fiber base layer and the functional layer, which can effectively resist the damage of repeated washing.

[0062] Comparative example 3 The purpose of the present comparative example is to observe the influence of the amount of each functional component (TOCNF, hydrophobic agent) in the coating liquid on the performance of the fabric, specifically: The waterproof and breathable fabric was prepared according to the parameters in Table 4, and its performance was tested (the remaining parameters were the same as in example 1), and the performance test indexes and methods were referred to example 1. The experimental results of each group of comparative example 3 and example 1 are shown in Table 4.

[0063] Table 4 Experimental results of each group of comparative example 3 and example 1

[0064] The experimental data of this comparative example show that: When the amount of hydrophobic agent is fixed, the amount of TOCNF has a significant influence on the experimental results. When the amount of TOCNF is 15 parts (comparative example 3-1), the coating network is fragile, and the hydrostatic pressure is only 8.5 kPa after 50 times of washing, and the WVTR retention rate is reduced to 36.0%; when the amount is increased to 30 parts (example 1), a stable three-dimensional network is formed, and the hydrostatic pressure is maintained at 50.2 kPa after washing (the same as example 2, the hydrostatic pressure retention rate is 96.0%), and the WVTR retention rate is as high as 97.9%; while the amount of 45 parts (comparative example 3-2) is excessive, and micro-cracks are generated due to the excessive rigidity of the coating, resulting in a decrease in the hydrostatic pressure to 38.5 kPa, and the WVTR retention rate is only 38.5%.

[0065] Meanwhile, the amount of hydrophobic agent also shows significant influence on the waterproof performance of the waterproof layer. When the amount of TOCNF is 3 parts (comparative example 3-3), the waterproof layer cannot form an effective waterproof barrier, and the hydrostatic pressure decreases to 5.6 kPa after washing, and the WVTR retention rate is 42.1%. When the amount of TOCNF is 10 parts (example 1), the hydrophobic agent is well compatible with the polymer network, achieving the best durability. When the amount of TOCNF is 18 parts (comparative example 3-4), the hydrophobic agent migrates due to agglomeration, and the hydrostatic pressure decreases to 36.2 kPa after washing, and the WVTR retention rate is only 39.1%.

[0066] The formulation of example 1 (TOCNF 30 parts + hydrophobic agent 10 parts) still maintains a hydrostatic pressure of 50.2 kPa and a WVTR retention rate of 97.9% after 50 rigorous washes, proving that it achieves the best balance in terms of long-term durability of waterproofness and air permeability. In the formulation of this example, TOCNF provides mechanical reinforcement and stability, and the hydrophobic agent ensures waterproof function. The experimental results show that the two components produce a synergistic effect in a specific ratio, achieving long-term stability of waterproofness and intelligent air permeability.

[0067] The above examples are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the purpose and scope of the present application, and all should be covered in the scope of the claims of the present application. The technical, shape, and structure parts not described in detail in the present application are well-known technologies.

Claims

1. A waterproof and breathable material, characterized in that, The coating liquid is formed from the following components, by mass parts: Temperature-sensitive N-tert-butylacrylamide-acrylamide copolymer: 80-120 parts; Crosslinking monomer: N,N'-methylenebisacrylamide: 3-10 parts; Photoinitiator: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone: 5-15 parts; TEMPO-oxidized nanocellulose: 20-40 parts; Hydrophobic finishing agent: perfluorooctyltriethoxysilane: 5-15 parts; Solvent: Deionized water: 1000 parts.

2. The waterproof and breathable material according to claim 1, characterized in that: In the thermosensitive N-tert-butylacrylamide-acrylamide copolymer, the molar ratio of N-tert-butylacrylamide to acrylamide is (2.5~3.5):

1.

3. A waterproof and breathable fabric, characterized in that: It includes a base layer and a functional layer composited on the surface of the base layer; the functional layer is formed by coating and curing the waterproof and breathable material according to any one of claims 1 to 2.

4. The waterproof and breathable fabric according to claim 3, characterized in that: The base layer is a cellulose fiber fabric, and TEMPO oxidized cellulose nanofibers are covalently anchored on the fiber surface by silane coupling agents and chemical crosslinking agents.

5. The waterproof and breathable fabric according to claim 4, characterized in that: The silane coupling agent is γ-aminopropyltriethoxysilane.

6. The waterproof and breathable fabric according to claim 4, characterized in that: The chemical crosslinking agent is a mixture of EDC and NHS.

7. A method for preparing a waterproof and breathable fabric as described in any one of claims 3-6, characterized in that, Includes the following steps: (1) Selection of base layer: Select fiber fabric as base layer fabric; (2) Plasma treatment: Plasma treatment is performed on the base fabric under a power of 700-900W; (3) Silanization treatment: The base fabric treated by plasma in step (2) is immersed in a silane coupling agent aqueous solution with a mass concentration of 1-3%, and a two-dip two-roll process is adopted with a roll-off rate of 70-80%. Then it is dried to obtain the base fabric obtained in step (3). (4) TOCNF anchoring: The base fabric obtained in step (3) is immersed in TEMPO oxidized nanocellulose aqueous dispersion activated by EDC and NHS, and reacted at 40-60℃ for 1-2 hours. After the reaction is completed, ultrasonic hot water washing and drying are performed to obtain the fabric after TOCNF anchoring. (5) Preparation of coating solution: Weigh each component of the coating solution, mix them, and obtain the coating solution; (6) Coating and pre-drying: Apply the coating liquid to the surface of the fabric after TOCNF anchoring and pre-dry; (7) UV curing: Under conditions where the temperature is below 35℃, UV light is used for curing to obtain the cured fabric; (8) Post-treatment: Wash the cured fabric and then dry it.

8. The preparation method according to claim 7, characterized in that: In step (4), the molar ratio of EDC to NHS is 2:1, and the amount of EDC added is 1.0-1.5 times the molar amount of carboxyl groups in TOCNF.

9. The preparation method according to claim 7, characterized in that: The drying temperature described in step (8) is 60-80℃.

10. The application of the waterproof and breathable material as described in any one of claims 1-2 or the waterproof and breathable fabric as described in any one of claims 3-6 in the preparation of outdoor sportswear, protective clothing or medical protective textiles.

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