A waterproof and breathable material, fabric and preparation method

Abstract

This invention relates to the field of polymer materials and functional textile fabrics, specifically to a waterproof and breathable material, fabric, and preparation method. The waterproof and breathable material is formed by UV curing a coating liquid containing components such as a thermosensitive N-tert-butylacrylamide-acrylamide copolymer, TEMPO oxidized nanocellulose, and a hydrophobic finishing agent, perfluorooctyltriethoxysilane. This invention controls the molar ratio of copolymer monomers to (2.5~3.5):1, regulating the material's lower critical solution temperature (LCST) to 15-20℃, giving the fabric intelligent responsive characteristics of "low breathability at low temperatures and high breathability at high temperatures," meeting human comfort requirements. Simultaneously, the surface of the fabric's base layer fibers is covalently anchored to TOCNF, serving as a robust intermediate layer, greatly enhancing the interfacial bonding and durability between the functional layer and the substrate. The fabric prepared by this invention exhibits significant intelligent response and excellent wash durability, and can be widely used in outdoor clothing, medical protective clothing, and other fields.

Description

Technical Field

[0001] This invention relates to the field of polymer materials and functional textile fabrics, and in particular to a waterproof and breathable material, fabric, and preparation method. Background Technology

[0002] Waterproof and breathable fabrics are an important branch of functional textile materials, widely used in outdoor clothing, protective equipment, and medical textiles. Their traditional technical approaches mainly fall into two categories: one uses microporous membranes (such as ePTFE and PU membranes) to block liquid water while allowing water vapor molecules to pass through; the other utilizes hydrophilic non-porous membranes (such as TPU) that rely on the hydrophilic groups of the polymer chains to achieve the adsorption-transfer-desorption of water molecules. However, the breathability of these traditional fabrics is usually static and cannot be dynamically adjusted according to the external environment or the body's condition.

[0003] To achieve dynamic regulation, intelligent responsive materials have been introduced into the textile field. Among them, thermosensitive polymers, due to their ability to undergo phase transitions in response to changes in ambient temperature, thereby altering their swelling state and chain segment fluidity, have become a research hotspot. For example, Chinese invention patent CN101302718B discloses a method for preparing a thermosensitive intelligent anti-soak fabric and its products. This technical solution applies a dry hydrogel coating of thermosensitive N-tert-butylacrylamide and acrylamide copolymer to the anti-soak clothing fabric. This coating is breathable and moisture-permeable in normal environments, but quickly seals in moisture upon contact with water, improving the material's anti-soak performance. Simultaneously, it possesses thermosensitive intelligence, automatically adjusting the water and moisture permeability according to ambient temperature, enhancing the waterproof performance of the clothing. This solves the problem of insufficient waterproof and breathable properties in Type B anti-soak clothing fabrics, achieving efficient waterproof performance and temperature-sensitive regulation, thus improving the waterproof performance and comfort of the clothing.

[0004] However, the adjustment mode of such fabrics disclosed in CN101302718B is exactly the opposite of the comfort needs of the human body in real-world environments. In normal wearing scenarios, the human body needs windproof and warm fabrics to reduce heat loss in low-temperature environments, requiring low breathability; in high-temperature environments or during exercise and sweating, the fabric needs to quickly wick away moisture and breathe to stay dry, requiring high breathability. Existing PNIPAM-based fabrics cannot meet this functional requirement of "windproof in low temperatures and breathable in high temperatures." Furthermore, existing temperature-sensitive smart fabrics face another major technical bottleneck: poor interfacial bonding strength. The temperature-sensitive polymer layer and the textile substrate are mainly bonded through physical coating. During repeated swelling-shrinkage cycles or washing, the waterproof and breathable material is prone to detachment and powdering, leading to rapid degradation of smart functions and severely insufficient durability.

[0005] Therefore, there is an urgent need in this field for a new type of smart fabric that can not only achieve the functional reversal of "low-temperature windproof and high-temperature breathable" to meet the needs of human comfort, but also must have a robust interface bond to ensure the long-term stability of the smart adjustment function. Summary of the Invention

[0006] To address the aforementioned technical problems, the present invention aims to provide a waterproof and breathable material, fabric, and preparation method. It seeks to provide a polymer material and its application in functional textile fabrics. This functional textile fabric possesses excellent intelligent adjustment functions while also exhibiting high hydrostatic pressure resistance and high durability, achieving a good balance between waterproofness, breathability, comfort, and durability.

[0007] To achieve the above-mentioned technical effects, the present invention adopts the following technical solution:

[0008] In a first aspect, the object of the present invention is to provide a waterproof and breathable material, formed from a coating liquid of the following components, in parts by mass:

[0009] Temperature-sensitive N-tert-butylacrylamide-acrylamide copolymer: 80-120 parts;

[0010] Crosslinking monomer N,N'-methylenebisacrylamide: 3-10 parts;

[0011] Photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone: 5-15 parts;

[0012] TEMPO-oxidized nanocellulose: 20-40 parts;

[0013] Hydrophobic finishing agent perfluorooctyltriethoxysilane: 5-15 parts;

[0014] And the solvent, deionized water: 1000 parts.

[0015] As a preferred technical solution, in the thermosensitive N-tert-butylacrylamide-acrylamide copolymer, the molar ratio of N-tert-butylacrylamide to acrylamide is (2.5~3.5):1.

[0016] As a preferred technical solution, the low critical dissolution temperature of the waterproof and breathable material is controlled within the range of 15-20℃.

[0017] Secondly, the present invention further provides a waterproof and breathable fabric, which includes a base layer and a functional layer laminated on the surface of the base layer; the functional layer is formed by coating and curing the waterproof and breathable material.

[0018] As a preferred technical solution, the base layer is a cellulose fiber fabric, and TEMPO oxidized cellulose nanofibers are covalently anchored on the fiber surface by silane coupling agent and chemical crosslinking agent.

[0019] As a preferred technical solution, the silane coupling agent is γ-aminopropyltriethoxysilane.

[0020] As a preferred technical solution, the chemical crosslinking agent is a mixture of EDC and NHS.

[0021] Thirdly, the present invention further provides a method for preparing a waterproof and breathable fabric, comprising the following steps:

[0022] (1) Selection of base layer: Select fiber fabric as base layer fabric;

[0023] (2) Plasma treatment: Plasma treatment is performed on the base fabric under a power of 700-900W;

[0024] (3) Silanization treatment: The plasma-treated base fabric is immersed in a 1-3% silane coupling agent aqueous solution, 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).

[0025] (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.

[0026] (5) Preparation of coating solution: Weigh each component of the coating solution, mix them, and obtain the coating solution;

[0027] (6) Coating and pre-drying: Apply the coating liquid to the surface of the fabric after TOCNF anchoring and pre-dry;

[0028] (7) UV curing: Under conditions where the temperature is below 35℃, UV light is used for curing to obtain the cured fabric;

[0029] (8) Post-treatment: Wash the cured fabric and then dry it.

[0030] As a preferred technical solution, the method for preparing waterproof and breathable fabric includes the following steps:

[0031] (1) Selection of base layer: Select fiber fabric as base layer fabric; the fiber fabric is at least one of cotton, linen and viscose fiber.

[0032] (2) Plasma treatment: The base fabric is subjected to plasma treatment at a power of 700-900W (e.g., plasma treatment for 1-3 minutes).

[0033] (3) Silanization treatment: The base fabric obtained by plasma treatment is immersed in an aqueous solution of silane coupling agent with a mass concentration of 1-3%, and a two-dip and two-roll process is adopted with a roll-off rate of 70-80%, and then dried (for example, at 80-100℃ for 20-30 minutes).

[0034] (4) TOCNF anchoring: Immerse the base fabric obtained in step (3) in TEMPO oxidized nanocellulose aqueous dispersion activated by EDC and NHS, react at 40-60℃ for 1-2 hours, and after the reaction is completed, perform ultrasonic hot water washing and drying.

[0035] (5) Preparation of coating liquid: Weigh each component according to the above proportions, mix them, and prepare the coating liquid;

[0036] (6) Coating and pre-drying: Apply the coating liquid to the surface of the treated fabric and pre-dry (e.g., pre-dry at 70-90℃ for 3-5 minutes).

[0037] (7) UV curing: Under conditions where the temperature is below 35°C, irradiate with ultraviolet light (for example, irradiate with ultraviolet light with a wavelength of 395nm for 2-4 minutes).

[0038] (8) Post-treatment: Wash the cured fabric (e.g., in warm water at 40-60℃); and finally dry it.

[0039] 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.

[0040] As a preferred technical solution, the drying temperature in step (8) is 60-80℃.

[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0042] First, by precisely controlling the molar ratio of N-tert-butylacrylamide to acrylamide in the thermosensitive copolymer to (2.5~3.5), this invention successfully lowers the low critical solution temperature (LCST) of the material from around 32°C in traditional PNIPAM to the room temperature range of 15-20°C. This allows the polymer chains to hydrophilically swell and the pore size to decrease in low-temperature environments (below LCST, such as 15°C), thus reducing air permeability and improving windproof and warmth retention. In high-temperature environments (above LCST, such as 25°C), the polymer chains hydrophobically shrink and the pore size to increase, significantly improving air permeability and facilitating heat dissipation and moisture removal.

[0043] Meanwhile, this invention innovatively introduces TEMPO oxidized cellulose nanofiber (TOCNF) anchored by covalent bonds as a "molecular bridge" between the base layer and the functional layer. This structure, through plasma activation, silanization pretreatment, and the use of EDC / NHS chemical crosslinking agents, allows TOCNF to bond firmly to the fiber base layer via covalent bonds. Simultaneously, its large specific surface area and abundant hydroxyl groups enable it to form strong physical entanglement and hydrogen bonding with the upper functional layer. This multi-layered interface reinforcement design effectively prevents the functional layer from detaching and pulverizing during use and washing. After 50 accelerated washes, the fabric maintains a hydrostatic pressure and water vapor permeability retention rate of over 95%, achieving long-term stability of the intelligent functions.

[0044] Furthermore, the TEMPO oxidized nanocellulose (TOCNF) in the coating liquid provided by this invention not only enhances the interfacial bonding force but also forms a three-dimensional network structure in the cured coating, playing a role in strengthening and toughening. The hydrophobic finishing agent perfluorooctyltriethoxysilane endows the coating with durable waterproof performance. These components work synergistically with the temperature-sensitive polymer network, enabling the final fabric to possess excellent intelligent adjustment functions while also having high hydrostatic pressure resistance and high durability, achieving a good balance between waterproofness, breathability, comfort, and durability.

[0045] In summary, this invention primarily uses water as a solvent, and the coating is cured using UV light curing technology, resulting in low energy consumption and environmental friendliness. The entire process flow is rationally designed, with clearly defined parameter control, and good compatibility with existing textile dyeing and finishing equipment, making it highly suitable for large-scale industrial production. Detailed Implementation

[0046] The following embodiments are only used to illustrate the technical solutions of the present invention more clearly, and are therefore only examples and should not be used to limit the scope of protection of the present invention.

[0047] Those skilled in the art will understand that the present invention can be practiced even without certain specific details. In some other embodiments, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the invention. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Unless otherwise specified, all units used in this specification are International Standard Units (SI), and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors unavoidable in industrial production.

[0048] Unless otherwise specified, the experimental methods used in the following examples are all conventional methods; the materials, reagents, or instruments used, unless otherwise specified by the manufacturer, are all commercially available; and the conditions not specified in the examples are all performed under conventional conditions or conditions recommended by the manufacturer. Furthermore, this invention does not limit the source of the raw materials used; unless otherwise specified, the raw materials used in this invention are all commercially available products commonly found in this technical field. Unless otherwise specified, the "ratio" referred to in the following examples refers to a ratio of parts by mass.

[0049] Unless otherwise specified, the base layer used in the examples is a cellulose fiber fabric (such as cotton fabric), whose fiber surface is covalently anchored to TEMPO oxidized nanocellulose (TOCNF) by a silane coupling agent (γ-aminopropyltriethoxysilane) and a chemical crosslinking agent (EDC / NHS mixture).

[0050] Example 1

[0051] The purpose of this embodiment is to prepare a waterproof and breathable material and its fabric, as detailed below:

[0052] First, the method for preparing a waterproof and breathable material provided in this embodiment is as follows:

[0053] According to the mass fractions, 100 parts of thermosensitive N-tert-butylacrylamide-acrylamide copolymer (molar ratio of N-tert-butylacrylamide 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-methylphenylacetone, 30 parts of TEMPO oxidized nanocellulose (purchased from Nanjing Tianlu Nanotechnology Co., Ltd.), and 10 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane were mixed with 1000 parts of deionized water to form a coating liquid. After photocuring, the coating liquid can form a waterproof and breathable material. The low critical solution temperature (LCST) of the waterproof and breathable material formed by the coating liquid was controlled at 17°C. The waterproof and breathable material formed by the coating liquid was recorded as A1.

[0054] Specifically, in the preparation process of this waterproof and breathable material, the synthesis of the thermosensitive N-tert-butylacrylamide-acrylamide copolymer is as follows:

[0055] Prepare the reactor and solvent: Add 100g of deionized water to a three-necked flask as a solvent and continuously purge with nitrogen gas for 30 minutes.

[0056] Preparation of mixed monomer aqueous solution: Dissolve N-tert-butylacrylamide (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 (at this time, the molar ratio of NTBAAm to AAm is 3:1), and transfer the solution to a constant pressure dropping funnel for later use.

[0057] Initialize the reaction system: Add 1.0 wt% of the initiator azobisisobutyramidine hydrochloride (AIBA, 0.153 g) to the three-necked flask that has been purged with nitrogen and contains solvent, and stir to fully dissolve it in water to obtain the reaction system.

[0058] Polymerization reaction: Under continuous nitrogen protection and stirring, the reaction system was heated to 70°C and maintained at a constant temperature. Subsequently, the prepared mixed monomer aqueous solution was slowly added dropwise to the reaction system through a constant pressure dropping funnel, with the dropping time controlled to be approximately 1 hour.

[0059] Incubation and maturation: After the addition is complete, continue stirring at 70°C for 5 hours to allow the polymerization reaction to proceed fully.

[0060] After the reaction was complete, the resulting reaction solution was poured into a large amount (approximately 500 mL) of acetone to settle. After the polymer precipitated, the white precipitate was collected by filtration and washed three times with acetone to remove unreacted monomers and impurities. Finally, the product was dried in a vacuum drying oven at 50°C for 24 hours to obtain a white solid thermosensitive copolymer.

[0061] Based on the aforementioned waterproof and breathable materials, the present invention further provides a waterproof and breathable fabric, the preparation method of which includes:

[0062] Base layer selection: Cotton fabric is selected as the base layer fabric;

[0063] 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 gas pressure of 30 Pa and power of 800W, it is treated for 2 minutes to improve the surface activity and roughness of the fabric, introduce polar groups, and enhance its bonding force with subsequent treatment layers.

[0064] Silanization treatment: The plasma-treated base fabric is immersed in a 2% (w / w) aqueous solution of γ-aminopropyltriethoxysilane in ethanol (ethanol to water volume ratio of 1:4) using a two-dip, two-roll process (i.e., immersion, rolling, re-immersion, re-rolling), controlling the roll-off rate (liquid absorption rate) to 78% to ensure uniform delivery of the silane coupling agent 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 strong silanized layer, resulting in a silanized fabric.

[0065] TOCNF anchoring:

[0066] a. Preparation of TOCNF dispersion: Weigh TEMPO oxidized cellulose nanoparticles (TOCNF, the carboxyl content of which was determined to be 1.2 mmol / g by conductivity titration) and prepare an aqueous dispersion with a concentration of 0.5 wt%.

[0067] b. Carboxyl group activation: Based on the volume, concentration, and carboxyl group content of the prepared dispersion, calculate the total molar amount of carboxyl groups. Using this as a basis, accurately weigh the chemical crosslinking agents EDC and NHS, ensuring the added EDC is 1.2 times the total molar amount of carboxyl groups and the molar ratio of EDC to NHS is 2:1, and add them to the aqueous dispersion of TOCNF. Stir and activate at room temperature for 15 minutes to activate the carboxyl groups on the surface of TOCNF, forming active esters that readily react with amine groups, thus obtaining the activated TOCNF dispersion.

[0068] c. Covalent grafting: The silanized fabric is immersed in the activated TOCNF dispersion and shaken in a 50°C water bath for 1.5 hours to allow the carboxyl groups of the activated TOCNF to covalently bond with the amine groups exposed in the silane layer on the fabric surface, thus achieving a firm anchoring of TOCNF on the fiber surface.

[0069] d. Post-washing: After the reaction in step c is completed, the fabric is taken out and washed with ultrasonic-assisted hot water to remove the physically adsorbed TOCNF. Finally, it is dried at 80°C for 30 minutes to obtain a base fabric with TOCNF anchored on the surface (fabric treated with TOCNF anchoring).

[0070] Coating liquid preparation: According to the above-mentioned method for preparing waterproof and breathable materials, accurately weigh the thermosensitive copolymer, crosslinking monomer, photoinitiator, TOCNF, hydrophobic finishing agent and deionized water, mix them and stir thoroughly until uniform to form a stable coating liquid.

[0071] Coating and pre-baking:

[0072] a. Coating: Apply the prepared coating liquid evenly to the surface of the silanized fabric. During the coating process, precisely control the amount of wet coating applied to be 120 g / m², and ensure uniform coating.

[0073] b. Pre-drying: Immediately transfer the coated fabric to a forced-air drying oven and pre-dry at 80°C for 4 minutes. This step aims to remove most of the moisture, allowing the coating to initially form a film, and to prevent bubbles or adverse effects on the curing result due to excessive moisture during subsequent UV curing.

[0074] UV curing: At room temperature, the pre-dried fabric is placed in a UV curing device and irradiated with ultraviolet light with a wavelength of 395nm for 3 minutes, so that the monomers and polymers in the coating liquid undergo photocrosslinking reaction to form a three-dimensional network structure and complete the curing of the functional layer.

[0075] Post-treatment: The UV-cured fabric is immersed in 50°C warm water and gently agitated to remove unreacted monomers, oligomers, and residual additives. Finally, it is dried at 80°C to obtain the final waterproof and breathable smart fabric (recorded as A2). This fabric's functional layer is firmly bonded to the base layer, possessing excellent waterproofness, controllable breathability, and washability.

[0076] The resulting fabric has excellent waterproof and breathable properties, and the interface is firmly bonded. The waterproof and breathable fabric prepared by this method is recorded as A2.

[0077] Example 2

[0078] Please refer to Example 1. This example is similar to Example 1, mainly by fine-tuning the process parameters to prepare a waterproof and breathable material and its fabric. Specifically:

[0079] The coating liquid formulation provided in this embodiment is as follows: 90 parts of thermosensitive N-tert-butylacrylamide-acrylamide copolymer (molar ratio of N-tert-butylacrylamide to acrylamide 3:1), 5 parts of crosslinking monomer N,N'-methylenebisacrylamide, 12 parts of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, 25 parts of TOCNF, 8 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane, and 1000 parts of solvent deionized water. The LCST of the material prepared using this coating liquid is 16°C.

[0080] The thermosensitive N-tert-butylacrylamide-acrylamide copolymer was synthesized using the same steps as in Example 1, but the monomer feed ratio was adjusted to N-tert-butylacrylamide (13.55 g, 0.105 mol) and acrylamide (2.25 g, 0.031 mol) to achieve a molar ratio of 3.4:1. The initiator AIBA was used at 1.2 wt% (0.190 g) of the total monomer mass, the reaction temperature was controlled at 65°C, and the reaction time was extended to 6.5 hours.

[0081] The preparation method of the waterproof and breathable fabric provided in this 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, and the gas pressure is controlled at 30 Pa, the power at 750 W, and the treatment time is 2.5 minutes; (3) Silanization treatment: The fabric after plasma treatment is immersed in a solution with a mass concentration of 1.5 In % γ-aminopropyltriethoxysilane ethanol aqueous solution (volume ratio of ethanol to water is 1:4), the roll-off rate is controlled at 78%. During 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 silanized layer to obtain the silanized fabric; (4) TOCNF anchoring: reaction temperature 45°C, time 1.8 hours, EDC addition amount is 1.1 times the carboxyl molar amount of TOCNF; (6) coating and pre-drying: pre-drying temperature 75°C, time 4.5 minutes; (7) UV curing: temperature 32°C, UV irradiation for 2.5 minutes; (8) post-treatment: washing temperature 45°C, drying temperature 75°C.

[0082] Example 3

[0083] Please refer to Example 1. This example is similar to Example 1, mainly by fine-tuning the process parameters to prepare a waterproof and breathable material and its fabric. Specifically:

[0084] The coating liquid formulation provided in this embodiment is as follows: 110 parts of thermosensitive N-tert-butylacrylamide-acrylamide copolymer (molar ratio of N-tert-butylacrylamide to acrylamide 3:1), 8 parts of crosslinking monomer N,N'-methylenebisacrylamide, 8 parts of photoinitiator 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylphenylacetone, 35 parts of TOCNF, 12 parts of hydrophobic finishing agent perfluorooctyltriethoxysilane, and 1000 parts of solvent deionized water.

[0085] The LCST of the material prepared using this coating liquid is 18℃.

[0086] The thermosensitive N-tert-butylacrylamide-acrylamide copolymer was synthesized using the same steps as in Example 1, but with the monomer feed ratio adjusted to N-tert-butylacrylamide (12.28 g, 0.095 mol) and acrylamide (2.49 g, 0.035 mol) to achieve a molar ratio of 2.7:1. The initiator AIBA was used at 0.8 wt% (0.118 g) of the total monomer mass, the reaction temperature was increased to 75°C, and the reaction time was shortened to 5.5 hours.

[0087] The preparation method of the waterproof and breathable fabric provided in this 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, and the gas pressure is controlled at 30 Pa, the power at 850 W, and the treatment time is 1.5 minutes; (3) Silanization treatment: The fabric after plasma treatment is immersed in a solution with a mass concentration of 2.5 In % γ-aminopropyltriethoxysilane ethanol aqueous solution (volume ratio of ethanol to water is 1:4), the roll-off rate is controlled at 72%. During 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 silanized layer to obtain the silanized fabric; (4) TOCNF anchoring: reaction temperature 55°C, time 1.2 hours, EDC addition amount is 1.4 times the carboxyl molar amount of TOCNF; (6) coating and pre-drying: pre-drying temperature 85°C, time 3.5 minutes; (7) UV curing: temperature 28°C, UV irradiation for 3.5 minutes; (8) post-treatment: washing temperature 55°C, drying temperature 78°C.

[0088] Comparative Example 1

[0089] The purpose of this comparative example is to synthesize a thermosensitive copolymer by setting a series of gradient molar ratios and to accurately measure its LCST and air permeability at key temperature points (15°C, 25°C) to demonstrate the effect of the molar ratio of NTBAAm to AAm on the fabric function. This experiment keeps the fabric preparation process completely consistent with Example 1, only systematically changing the molar ratio of monomers when synthesizing the thermosensitive copolymer, to prepare waterproof and breathable materials and waterproof and breathable fabrics respectively.

[0090] Experimental results: Differential scanning calorimetry (DSC) was used to accurately determine the LCST of each waterproof and breathable material, and the water vapor transmission rate (WVTR, g / m²·24h) of the waterproof and breathable fabric prepared using the material was tested at 15℃ and 25℃.

[0091] The experimental results of each group in Comparative Example 1 and Example 1 are shown in Table 1.

[0092] Table 1. Experimental results of each group in Comparative Example 1 and Example 1

[0093]

[0094] The above experimental results show that as the proportion of the hydrophobic component NTBAAm increases, the LCST of the copolymer gradually decreases from 26.3℃ in Comparative Example 1-1 to 11.3℃ in Comparative Example 1-6. However, the value of LCST itself is not the only key factor; the dynamic change pattern of water vapor transmission rate (WVTR) caused by its position relative to the ambient temperature is the core of solving the technical problem of this invention. The data shows that when the molar ratio is lower than 2.5:1 (such as Comparative Examples 1-1 and 1-2), the LCST is too high (>24℃), and the WVTR of the fabric increases slowly during the temperature rise from 10℃ to 20℃. Its main improvement in air permeability occurs after 20℃, and it cannot achieve effective intelligent regulation in the room temperature range. More importantly, the traditional PNIPAM material (Comparative Examples 1-7) exhibits a completely opposite "intelligent" mode because its LCST (31.8℃) is much higher than the test temperature range, that is, the air permeability decreases as the temperature rises (WVTR at 30℃ is 20.51% lower than at 20℃).

[0095] When the molar ratio of NTBAAm to AAm is controlled between 2.5:1 and 3.5:1, the LCST can be precisely set between 13.2℃ and 19.6℃, thus allowing the fabric's breathability abrupt change point to fall within the actual wearing environment of 10-30℃. As shown in Example 1 (molar ratio 3.0:1, LCST = 17.2℃), at low temperatures (10℃), WVTR remains at a low level (2855 g / m²·24h), which is beneficial for windproofing and warmth retention. When the temperature rises to 20℃ (above LCST), WVTR experiences a significant jump (change rate +51.17%), demonstrating obvious phase transition behavior. When the temperature further rises to 30℃, WVTR continues to increase to 5983 g / m²·24h, ensuring heat dissipation requirements at high temperatures. This "low-temperature, low-breathability; high-temperature, high-breathability" mode fully meets the physiological comfort needs of the human body.

[0096] When the molar ratio of NTBAAm to AAm exceeds 3.5:1 (as in Comparative Examples 1-4), although the rate of change from 20°C to 10°C is extremely high, its WVTR value at 30°C is slightly lower than that at 20°C. This indicates that the excessively low LCST causes the phase transition process to be too rapid and complete prematurely, potentially reaching the breathability limit at room temperature, thus affecting the linear growth of performance. Furthermore, its low-temperature baseline WVTR is too low (only 1813 in Comparative Examples 1-6), impacting daily comfort. When the molar ratio is 2.5:1 (Comparative Examples 1-3), the rate of change of WVTR from 30°C to 20°C is only 4.66%, indicating that the phase transition-driven increase in high breathability is nearing its end, and the range of intelligent adjustment is limited. Therefore, the molar ratio (3.0:1) in Example 1 achieves the best balance among basic windproofness, high-temperature breathability, and the range of intelligent response.

[0097] Comparative Example 2

[0098] The purpose of this comparative study is to observe the effects of "plasma treatment" and "TOCNF covalent anchoring" on the durability of waterproof and breathable fabrics. Specifically:

[0099] The interface processing methods of each group in Comparative Example 2 and Example 1 are shown in Table 2.

[0100] Table 2. Interface processing methods for each group in Comparative Example 2 and Example 1

[0101]

[0102] The waterproof and breathable fabrics prepared according to the above comparative proportions were tested, including:

[0103] Washing durability: Accelerated washing test was conducted in accordance with AATCC 61-2020 2A standard, simulating 50 household washes.

[0104] Performance testing: The hydrostatic pressure of the fabric before and after washing (refer to GB / T 4744-2013) and the water vapor transmission rate (WVTR) at 25℃ were tested respectively, and the retention rate was calculated.

[0105] The experimental results of each group in Comparative Example 2 and Example 1 are shown in Table 3.

[0106] Table 3. Experimental results of each group in Comparative Example 2 and Example 1

[0107]

[0108] The experimental results show that:

[0109] Comparative Example 2-1, without any reinforcement treatment, exhibited the worst bonding strength. After 50 washes, the functional layer severely detached, with a hydrostatic retention rate of only 29.4% and a WVTR retention rate dropping to 35.1%, resulting in extremely low performance retention. Plasma treatment alone (Comparative Example 2-2) increased the specific surface area through physical etching, improving bonding strength. The hydrostatic retention rate increased to 42.9%, and the WVTR retention rate reached 47.9%. Introducing silanization treatment (Comparative Example 2-3) significantly improved durability through chemical bonding, with marked increases in both hydrostatic retention rate and WVTR retention rate. The complete treatment used in Example 1 (including TOCNF anchoring) brought about a qualitative leap, achieving a hydrostatic retention rate of 96.0% and a WVTR retention rate of 97.9%. This demonstrates that TOCNF, acting as a "molecular bridge," forms a strong covalent bond and physical entanglement network with the fiber base layer and functional layer, effectively resisting damage from repeated washing.

[0110] Comparative Example 3

[0111] The purpose of this comparative example is to observe the effect of the dosage of each functional component (TOCNF, hydrophobic agent) in the coating liquid on the fabric performance, specifically:

[0112] Waterproof and breathable fabrics were prepared according to the parameters in Table 4 and their performance was tested (the remaining parameters were the same as in Example 1). The performance test indicators and methods were the same as in the examples. The experimental results of each group of Comparative Example 3 and Example 1 are shown in Table 4.

[0113] Table 4. Experimental results of each group in Comparative Example 3 and Example 1

[0114]

[0115] This comparative experimental data shows that:

[0116] When the amount of hydrophobic agent was fixed, the amount of TOCNF had a significant impact on the experimental results. When the amount of TOCNF was 15 parts (Comparative Example 3-1), the coating network was fragile, and after 50 washes, the hydrostatic pressure was only 8.5 kPa, and the WVTR retention rate dropped to 36.0%. When the amount of TOCNF was increased to 30 parts (Example 1), a stable three-dimensional network was formed, and the hydrostatic pressure was maintained at 50.2 kPa after washing (same as Example 2, with a hydrostatic pressure retention rate of 96.0%), and the WVTR retention rate was as high as 97.9%. However, when an excessive amount of 45 parts was used (Comparative Example 3-2), microcracks were generated due to the excessive rigidity of the coating, resulting in a drop in hydrostatic pressure to 38.5 kPa and a WVTR retention rate of only 38.5%.

[0117] Meanwhile, with a fixed amount of TOCNF, the amount of hydrophobic agent also has a significant impact. When the amount of TOCNF is 3 parts (Comparative Example 3-3), it cannot form an effective waterproof barrier. After washing, the hydrostatic pressure drops to 5.6 kPa and the WVTR retention rate is 42.1%. When the amount of TOCNF is 10 parts (Example 1), it is well compatible with the polymer network and achieves the best durability. When the amount of TOCNF is 18 parts (Comparative Example 3-4), due to the aggregation and migration of the hydrophobic agent, the hydrostatic pressure drops to 36.2 kPa after washing and the WVTR retention rate is only 39.1%.

[0118] The formulation of Example 1 (30 parts TOCNF + 10 parts hydrophobic agent) maintained a hydrostatic pressure of 50.2 kPa and a WVTR retention rate of 97.9% after 50 rigorous washes, demonstrating that it achieves the best balance between waterproofness and breathability in long-term durability. In this formulation, TOCNF provides mechanical reinforcement and stability, while the hydrophobic agent ensures waterproof function. The experimental results show that the two produce a synergistic effect under a specific ratio, achieving long-term stability of waterproofness and intelligent breathability.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications and substitutions should be covered within the scope of the claims of the present invention. Technical aspects, shapes, and structures not described in detail in this invention are all well-known technologies.

Claims

1. A waterproof, breathable material, characterized in that, A coating liquid formed from the following components, in parts by mass: A temperature-sensitive N-tert-butylacrylamide-acrylamide copolymer: 90-110 parts; A cross-linking monomer: N, N'-methylenebisacrylamide: 5-8 parts; A photoinitiator: 2-hydroxy-4'-(2-hydroxyethoxy)-2-methylpropiophenone: 8-12 parts; TEMPO-oxidized nanocellulose: 25-35 parts; A hydrophobic finishing agent: perfluorooctyltriethoxysilane: 8-12 parts; A solvent: deionized water: 1000 parts; wherein the molar ratio of N-tert-butylacrylamide to acrylamide in the temperature-sensitive N-tert-butylacrylamide-acrylamide copolymer is (2.7-3.4):

1.

2. A waterproof, breathable fabric, characterized in that: The waterproof and breathable material according to claim 1 or the waterproof and breathable fabric according to any one of claims 2-5.

3. A waterproof and breathable fabric according to claim 2, characterized in that: 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 cross-linking agent.

4. A waterproof and breathable fabric according to claim 3, characterized in that: The silane coupling agent is γ-aminopropyltriethoxysilane.

5. A waterproof and breathable fabric according to claim 3, characterized in that: The chemical cross-linking agent is a mixture of EDC and NHS.

6. A method of making a waterproof, vapor-permeable fabric according to any one of claims 2-5, characterized in that, The method comprises the following steps: (1) Base layer selection: selecting a fiber fabric as the base layer fabric; (2) Plasma treatment: treating the base layer fabric with plasma under a power of 700-900 W; (3) Silanization treatment: immersing the base layer fabric treated with plasma in step (2) in a silane coupling agent aqueous solution with a mass concentration of 1-3%, adopting a two-dip-two-pad process with a pad pickup rate of 70-80%, and then drying to obtain the base layer fabric treated in step (3); (4) TOCNF anchoring: immersing the base layer 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 the 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: curing under ultraviolet light irradiation at a temperature lower than 35°C to obtain the cured fabric; (8) Post-treatment: washing the cured fabric and finally drying.

7. The method of claim 6, wherein: 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.

8. The method of claim 6, wherein: In step (8), the drying temperature is 60-80°C.

9. Use of the waterproof and breathable material according to claim 1 or the waterproof and breathable fabric according to any one of claims 2-5 in the preparation of outdoor sports clothing, protective clothing, or medical protective textiles.

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