A soft antibacterial brocade nylon composite fabric and a preparation method thereof

Abstract

The present application relates to a kind of soft antibacterial brocade nylon composite fabric and its preparation method, belong to textile material technical field.The fabric is woven from 60-80wt% nylon fiber and 20-40wt% spandex fiber, and the surface of fiber is attached with the functional layer formed by the crosslinking solidification of reactive silicone-chitosan graft copolymer.The copolymer includes polydimethylsiloxane flexible main chain with reactive functional group, grafted water-soluble chitosan derivative antibacterial side chain and terminal blocked isocyanate group.Preparation method includes the steps of preparing post-treatment liquid, padding treatment, segmented heat setting, etc.The obtained fabric has excellent soft hand feeling and high efficient durable antibacterial performance, and is particularly suitable for preparing markless antibacterial bra, and can be widely used in intimate apparel field.

Description

Technical Field

[0001] This invention belongs to the field of textile materials technology and relates to a soft and antibacterial nylon-spandex composite fabric and its preparation method. Background Technology

[0002] Nylon-spandex composite fabric, made from a blend of nylon and spandex, combines the excellent abrasion resistance, crispness, and soft luster of nylon fibers with the ultra-high elastic recovery rate and body-hugging stretch of spandex fibers. The fabric has long-lasting resilience, dimensional stability, and a skin-friendly fit, adapting to the dynamic curves of the human body and meeting the wearing comfort and shaping needs of intimate apparel. Therefore, it is widely used in the field of intimate textile products such as sports bras and seamless bras, becoming one of the mainstream materials in the underwear fabric market.

[0003] To further optimize the wearing experience of intimate apparel and enhance the functionality and practicality of fabrics, existing textile technologies typically upgrade nylon-spandex fabrics through two main aspects: softening finishing and antibacterial modification. Regarding softening improvements, the industry often uses softeners such as amino silicone oil and polyether-modified silicone for padding finishing, reducing the surface friction coefficient of the fibers and giving the fabric a smooth and delicate feel. For enhancing antibacterial properties, antibacterial finishing agents such as chitosan, quaternary ammonium salts, and silver ions are commonly used. These are applied to the fiber surface through physical impregnation, coating blending, or simple cross-linking, relying on the antibacterial properties of the antibacterial components to inhibit bacterial growth, reduce odor, and meet the hygiene requirements of intimate apparel.

[0004] However, many insurmountable shortcomings remain, making it impossible to simultaneously achieve softness, antibacterial properties, and durability. Conventional silicone softeners adhere to the fiber surface only through physical adsorption, resulting in poor washability and issues such as silicone oil migration and deterioration of the hand feel after repeated washing. Traditional antibacterial agents such as chitosan have poor water solubility and are difficult to process; physical blending methods lead to rapid loss of antibacterial components, making it difficult to maintain the antibacterial effect, while also affecting the fabric's elasticity and softness. Furthermore, conventional finishing processes are difficult to match with the heat-setting characteristics of nylon-spandex fabrics; high-temperature treatment can easily cause the fabric to yellow and lose elasticity, and a single finishing agent cannot simultaneously achieve long-lasting softness and durable antibacterial properties, making it difficult to meet the stringent requirements of high-end seamless underwear for fabric functionality and durability. Summary of the Invention

[0005] The purpose of this invention is to provide a soft and antibacterial nylon-spandex composite fabric and its preparation method, thereby solving the technical problem that nylon-spandex fabrics in the prior art are difficult to achieve both a soft feel and high antibacterial efficiency.

[0006] The objective of this invention can be achieved through the following technical solutions: A soft and antibacterial nylon-spandex composite fabric is woven from 60-80 wt% nylon fibers and 20-40 wt% spandex fibers. A functional layer is attached to the surface of the fabric fibers. The functional layer is formed by cross-linking and curing of a reactive organosilicon-chitosan graft copolymer. The molecular structure of the reactive organosilicon-chitosan graft copolymer includes: (a) Flexible backbone: a polydimethylsiloxane backbone with reactive functional groups; wherein the reactive functional groups are selected from one or more of amino, epoxy, carboxyl, hydroxyl or mercapto groups; (b) Antibacterial side chain: a water-soluble chitosan derivative oligomer grafted onto the flexible backbone; (c) Reactive end groups: Closed isocyanate groups located at the ends of the molecular chain.

[0007] In this application, the low glass transition temperature and low surface energy of the polydimethylsiloxane backbone form a lubricating film on the fabric surface, reducing the coefficient of friction between fibers and giving the fabric a smooth and supple feel. The amino and epoxy functional groups introduced on the backbone not only serve as grafting points but also form hydrogen bonds or covalent bonds with amide groups (nylon) or urethane groups (spandex) on the fiber surface during subsequent crosslinking, preventing silicone oil migration. Chitosan and its derivatives are rich in cationic amino groups, which can adsorb negatively charged bacterial cell walls through electrostatic attraction, disrupting their osmotic pressure balance, causing leakage of bacterial contents and death. By chemically grafting chitosan oligomers onto the silicone oil backbone, the problems of traditional chitosan's insolubility in water and difficulty in finishing are solved, while avoiding the rapid loss of antibacterial agents caused by physical blending, thus achieving wash-resistant antibacterial properties. The closed isocyanate group at the end of the molecular chain is the key to resolving the contradiction between water stability and high-temperature crosslinking. At room temperature, the isocyanate group is protected by the blocking agent and does not undergo hydrolysis or self-polymerization. At 120-135℃, the blocking agent volatilizes and dissociates upon heating, releasing highly active -NCO groups, which react with the main chain and fiber. Then, the fiber is heat-set at 150-165℃ to eliminate weaving stress.

[0008] As a preferred embodiment of the present invention, the water-soluble chitosan derivative oligomer is selected from one or more of carboxymethyl chitosan, chitosan quaternary ammonium salt, or hydroxypropyl chitosan; The number-average molecular weight (Mn) of the oligomer is 1000-5000 Da, and the degree of deacetylation is ≥85%.

[0009] As a preferred embodiment of the present invention, the glass transition temperature Tg of the reactive organosilicon-chitosan graft copolymer is ≤ -50℃.

[0010] Furthermore, the preparation method of the soft and antibacterial nylon-spandex composite fabric includes the following steps: (1) Disperse the reactive organosilicon-chitosan graft copolymer, crosslinking agent, penetrant and pH adjuster in water, adjust the pH value to 5.0-6.5, and obtain the post-treatment solution; (2) The nylon-spandex composite fabric is immersed in the post-treatment solution, and after padding, the padding rate is controlled at 70%-80%, and then pre-drying and dehydration are carried out; (3) Perform segmented heat setting on the pre-baked fabric; (4) The finished product is obtained by washing and drying.

[0011] As a preferred embodiment of the present invention, the post-treatment liquid in step (1) is composed of the following components by mass: 8-12 parts of reactive organosilicon-chitosan graft copolymer Blocked isocyanate crosslinking agent 1.5-3.0 parts 0.2-0.5 parts of fatty alcohol polyoxyethylene ether Add an appropriate amount of glacial acetic acid to adjust the pH to 5.0-6.0. Add deionized water to bring the total to 100 parts.

[0012] As a preferred technical solution of the present invention, the immersion rolling process in step (2) is one immersion and one rolling or two immersions and two rolling.

[0013] As a preferred technical solution of the present invention, the pre-drying and dehydration temperature in step (2) is 80-100℃.

[0014] As a preferred embodiment of the present invention, the segmented heat setting in step (3) sequentially passes through two setting units at different temperature zones: First temperature zone: control the temperature at 120-135℃, and the processing time is 1-3 minutes; Second temperature zone: control the temperature at 150-165℃ and the processing time at 30-90 seconds.

[0015] As a preferred technical solution of the present invention, 0.5-2.0 parts by weight of an anti-heat yellowing agent is added to the post-treatment liquid in step (1). The anti-heat yellowing agent is selected from hindered amine light stabilizers, phosphite antioxidants or benzotriazole ultraviolet absorbers.

[0016] Furthermore, a seamless antibacterial bra, wherein the body layer, molded cup fabric and / or edge bonding strip are made of the soft antibacterial nylon-spandex composite fabric as described in any one of claims 1 to 3.

[0017] The beneficial effects of this invention are: (1) This invention constructs a reactive organosilicon-chitosan graft copolymer by chemically grafting a flexible organosilicon backbone with an antibacterial chitosan side chain. The polydimethylsiloxane backbone has a low glass transition temperature and low surface energy, forming a lubricating film on the fiber surface, significantly reducing the coefficient of friction between fibers and giving the fabric a smooth and soft feel. Simultaneously, the water-soluble chitosan derivative oligomers grafted onto the backbone are rich in cationic amino groups, which adsorb negatively charged bacterial cell walls through electrostatic attraction, disrupting their osmotic pressure balance and achieving highly efficient antibacterial properties. This overcomes the shortcomings of traditional chitosan, such as insolubility in water and difficulty in finishing, and avoids the problem of rapid loss of antibacterial agents caused by physical blending, achieving a balance between softness and antibacterial properties.

[0018] (2) The amino and epoxy functional groups on the main chain of the reactive organosilicon-chitosan graft copolymer of the present invention can form hydrogen bonds or covalent bonds with the amide group of nylon fiber and the urethane group of spandex fiber to prevent silicone oil migration; the closed isocyanate group at the end of the molecular chain is unsealed and releases highly active -NCO during heat treatment, which cross-links with the main chain functional group and fiber to form a three-dimensional network structure, locking the antibacterial side chain on the fiber surface, further greatly improving the antibacterial durability.

[0019] (3) The segmented heat setting process of the present invention is a key innovation to solve the contradiction between functional fixation and seamless processing. The first temperature zone (120-135℃) realizes the unsealing and cross-linking of closed isocyanate to form a preliminary network structure, avoiding thermal damage to the chitosan side chains at high temperature; the second temperature zone (150-165℃) completes the fiber heat setting, eliminates weaving stress, and gives the fabric better dimensional stability and thermoplasticity, achieving excellent seamless processing adaptability in bra cup molding and edge hot cutting processes: the cut is flat and melted, without detachment or hard edges, and the hot pressing shrinkage rate is low. Detailed Implementation

[0020] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with embodiments, is provided below.

[0021] Example 1 Nylon-spandex composite fabric: Warp-knitted fabric with a composition of 70wt% nylon 66 and 30wt% spandex, and a weight of 180 g / m². 2 .

[0022] Preparation of reactive organosilicon-chitosan graft copolymers: A1. Under nitrogen protection, 100 parts by weight of epoxy-terminated polydimethylsiloxane and 25 parts by weight of chitosan quaternary ammonium salt oligomer (Mn=2000 Da, degree of deacetylation ≥90%) were mixed, and dibutyltin dilaurate catalyst was added. The mixture was reacted at 82°C for 7 hours to obtain a hydroxyl-terminated grafting intermediate. A2. Add 8 parts by weight of isophorone diisocyanate to the intermediate and react at 60°C for 2 hours to introduce free isocyanate end groups. A3. Maintain 60°C, add 6.5 parts by weight of butanone oxime, react for 1.5 hours to obtain a blocked prepolymer; A4. Add a nonionic emulsifier to the prepolymer and shear it at high speed, then add deionized water dropwise for phase inversion emulsification. After vacuum distillation, a semi-transparent microemulsion with a solid content of 40% and a pH value of 6.0-6.5 is obtained.

[0023] A suitable amount of the reactive organosilicon-chitosan graft copolymer prepared in step A4 was tested by differential scanning calorimetry (DSC) according to ISO 11357-2 standard. The test conditions were a nitrogen atmosphere, a heating rate of 10℃ / min, and a temperature range of -100℃ to 50℃. The glass transition temperature Tg was measured to be -53℃.

[0024] Preparation of post-treatment solution: Add deionized water to a mixing tank equipped with a stirrer, turn on the stirrer (300 rpm), and add the components in the following proportions by mass: Reactive organosilicon-chitosan graft copolymer emulsion: 10 parts; Butanone oxime blocked hexamethylene diisocyanate (HDI) trimer aqueous dispersion (75% solids): 2.7 parts; Fatty alcohol polyoxyethylene ether: 0.3 parts; Hindered amine light stabilizer (HALS-770): 0.2 parts; Glacial acetic acid: Add an appropriate amount dropwise until the pH of the mixture stabilizes at 5.5; Deionized water: Add to a total of 100 parts by weight.

[0025] After feeding, high-speed shear emulsification (2000 rpm) was performed for 15 minutes to obtain a uniform and stable milky white post-treatment solution.

[0026] Preparation method of soft and antibacterial nylon-spandex composite fabric: (1) Immerse the nylon-spandex composite fabric in the above post-treatment solution and use a two-dip and two-roll process to control the roll-off rate to 75% to ensure that the fabric is evenly coated with liquid and has no dry or wet streaks. (2) Place the impregnated fabric in a hot air pre-drying oven and control the temperature at 90℃ for 3 minutes; (3) The pre-dried fabric is sent to a double-layer hot air tenter for segmented processing: First temperature zone (cross-linking curing zone): The temperature is controlled at 125℃, the wind speed is medium to high, and the fabric running speed is controlled so that the dwell time is 2 minutes. Second temperature zone (fiber setting zone): The temperature is controlled at 160℃, the wind speed is high, and the fabric running speed is controlled so that the dwell time is 45 seconds. (4) After the fabric is shaped, it is washed and dried at 100°C to obtain the finished soft antibacterial nylon-ammonia composite fabric.

[0027] Example 2 Nylon-spandex composite fabric: Warp-knitted fabric with a composition of 70wt% nylon 66 and 30wt% spandex, and a weight of 180 g / m². 2 .

[0028] Preparation of reactive organosilicon-chitosan graft copolymers: A1. Under nitrogen protection, 100 parts by weight of epoxy-terminated polydimethylsiloxane and 25 parts by weight of chitosan quaternary ammonium salt oligomer (Mn=2000 Da, degree of deacetylation ≥90%) were mixed, and dibutyltin dilaurate catalyst was added. The mixture was reacted at 82°C for 7 hours to obtain a hydroxyl-terminated grafting intermediate. A2. Add 8 parts by weight of isophorone diisocyanate to the intermediate and react at 60°C for 2 hours to introduce free isocyanate end groups. A3. Maintain 60°C, add 6.5 parts by weight of butanone oxime, react for 1.5 hours to obtain a blocked prepolymer; A4. Add a nonionic emulsifier to the prepolymer and shear it at high speed, then add deionized water dropwise for phase inversion emulsification. After vacuum distillation, a semi-transparent microemulsion with a solid content of 40% and a pH value of 6.0-6.5 is obtained.

[0029] A suitable amount of the reactive organosilicon-chitosan graft copolymer prepared in step A4 was tested by differential scanning calorimetry (DSC) according to ISO 11357-2 standard. The test conditions were a nitrogen atmosphere, a heating rate of 10℃ / min, and a temperature range of -100℃ to 50℃. The glass transition temperature Tg was measured to be -55℃.

[0030] Preparation of post-treatment solution: Add deionized water to a mixing tank equipped with a stirrer, turn on the stirrer (300 rpm), and add the components in the following proportions by mass: Reactive organosilicon-chitosan graft copolymer emulsion: 8.0 parts; Butanone oxime blocked hexamethylene diisocyanate (HDI) trimer aqueous dispersion (75% solids): 1.4 parts; Fatty alcohol polyoxyethylene ether: 0.3 parts; Hindered amine light stabilizer (HALS-770): 0.2 parts; Glacial acetic acid: Add an appropriate amount dropwise until the pH of the mixture stabilizes at 5.5; Deionized water: Add to a total of 100 parts by weight.

[0031] After feeding, high-speed shear emulsification (2000 rpm) was performed for 15 minutes to obtain a uniform and stable milky white post-treatment solution.

[0032] Preparation method of soft and antibacterial nylon-spandex composite fabric: (1) Immerse the nylon-spandex composite fabric in the above post-treatment solution and use a two-dip and two-roll process to control the roll-off rate to 75% to ensure that the fabric is evenly coated with liquid and has no dry or wet streaks. (2) Place the impregnated fabric in a hot air pre-drying oven and control the temperature at 90℃ for 3 minutes; (3) The pre-dried fabric is sent to a double-layer hot air tenter for segmented processing: First temperature zone (cross-linking curing zone): The temperature is controlled at 125℃, the wind speed is medium to high, and the fabric running speed is controlled so that the dwell time is 2 minutes. Second temperature zone (fiber setting zone): The temperature is controlled at 160℃, the wind speed is high, and the fabric running speed is controlled so that the dwell time is 45 seconds. (4) After the fabric is shaped, it is washed and dried at 100°C to obtain the finished soft antibacterial nylon-ammonia composite fabric.

[0033] Example 3 Nylon-spandex composite fabric: Warp-knitted fabric with a composition of 70wt% nylon 66 and 30wt% spandex, and a weight of 180 g / m². 2 .

[0034] Preparation of reactive organosilicon-chitosan graft copolymers: A1. Under nitrogen protection, 100 parts by weight of epoxy-terminated polydimethylsiloxane and 25 parts by weight of chitosan quaternary ammonium salt oligomer (Mn=2000 Da, degree of deacetylation ≥90%) were mixed, and dibutyltin dilaurate catalyst was added. The mixture was reacted at 82°C for 7 hours to obtain a hydroxyl-terminated grafting intermediate. A2. Add 8 parts by weight of isophorone diisocyanate to the intermediate and react at 60°C for 2 hours to introduce free isocyanate end groups. A3. Maintain 60°C, add 6.5 parts by weight of butanone oxime, react for 1.5 hours to obtain a blocked prepolymer; A4. Add a nonionic emulsifier to the prepolymer and shear it at high speed, then add deionized water dropwise for phase inversion emulsification. After vacuum distillation, a semi-transparent microemulsion with a solid content of 40% and a pH value of 6.0-6.5 is obtained.

[0035] A suitable amount of the reactive organosilicon-chitosan graft copolymer prepared in step A4 was tested by differential scanning calorimetry (DSC) according to ISO 11357-2 standard. The test conditions were a nitrogen atmosphere, a heating rate of 10℃ / min, and a temperature range of -100℃ to 50℃. The glass transition temperature Tg was measured to be -51℃.

[0036] Preparation of post-treatment solution: Add deionized water to a mixing tank equipped with a stirrer, turn on the stirrer (300 rpm), and add the components in the following proportions by mass: Reactive organosilicon-chitosan graft copolymer emulsion: 12 parts; Butanone oxime blocked hexamethylene diisocyanate (HDI) trimer aqueous dispersion (75% solids): 3.0 parts; Fatty alcohol polyoxyethylene ether: 0.3 parts; Hindered amine light stabilizer (HALS-770): 0.2 parts; Glacial acetic acid: Add an appropriate amount dropwise until the pH of the mixture stabilizes at 5.5; Deionized water: Add to a total of 100 parts by weight.

[0037] After feeding, high-speed shear emulsification (2000 rpm) was performed for 15 minutes to obtain a uniform and stable milky white post-treatment solution.

[0038] Preparation method of soft and antibacterial nylon-spandex composite fabric: (1) Immerse the nylon-spandex composite fabric in the above post-treatment solution and use a two-dip and two-roll process to control the roll-off rate to 75% to ensure that the fabric is evenly coated with liquid and has no dry or wet streaks. (2) Place the impregnated fabric in a hot air pre-drying oven and control the temperature at 90℃ for 3 minutes; (3) The pre-dried fabric is sent to a double-layer hot air tenter for segmented processing: First temperature zone (cross-linking curing zone): The temperature is controlled at 125℃, the wind speed is medium to high, and the fabric running speed is controlled so that the dwell time is 2 minutes. Second temperature zone (fiber setting zone): The temperature is controlled at 160℃, the wind speed is high, and the fabric running speed is controlled so that the dwell time is 45 seconds. (4) After the fabric is shaped, it is washed and dried at 100°C to obtain the finished soft antibacterial nylon-ammonia composite fabric.

[0039] Example 4 Nylon-spandex composite fabric: Warp-knitted fabric with a composition of 70wt% nylon 66 and 30wt% spandex, and a weight of 180 g / m². 2 .

[0040] Preparation of reactive organosilicon-chitosan graft copolymers: A1. Under nitrogen protection, 100 parts by weight of epoxy-terminated polydimethylsiloxane and 25 parts by weight of chitosan quaternary ammonium salt oligomer (Mn=2000 Da, degree of deacetylation ≥90%) were mixed, and dibutyltin dilaurate catalyst was added. The mixture was reacted at 82°C for 7 hours to obtain a hydroxyl-terminated grafting intermediate. A2. Add 8 parts by weight of isophorone diisocyanate to the intermediate and react at 60°C for 2 hours to introduce free isocyanate end groups. A3. Maintain 60°C, add 6.5 parts by weight of butanone oxime, react for 1.5 hours to obtain a blocked prepolymer; A4. Add a nonionic emulsifier to the prepolymer and shear it at high speed, then add deionized water dropwise for phase inversion emulsification. After vacuum distillation, a semi-transparent microemulsion with a solid content of 40% and a pH value of 6.0-6.5 is obtained.

[0041] A suitable amount of the reactive organosilicon-chitosan graft copolymer prepared in step A4 was taken and subjected to differential scanning calorimetry (DSC) testing according to ISO 11357-2 standard. The test conditions were a nitrogen atmosphere, a heating rate of 10℃ / min, and a temperature range of -100℃ to 50℃. The glass transition temperature Tg was measured to be -52℃.

[0042] Preparation of post-treatment solution: Add deionized water to a mixing tank equipped with a stirrer, turn on the stirrer (300 rpm), and add the components in the following proportions by mass: Reactive organosilicon-chitosan graft copolymer emulsion: 10 parts; Butanone oxime blocked hexamethylene diisocyanate (HDI) trimer aqueous dispersion (75% solids): 2.7 parts; Fatty alcohol polyoxyethylene ether: 0.3 parts; Hindered amine light stabilizer (HALS-770): 0.2 parts; Glacial acetic acid: Add an appropriate amount dropwise until the pH of the mixture stabilizes at 5.5; Deionized water: Add to a total of 100 parts by weight.

[0043] After feeding, high-speed shear emulsification (2000 rpm) was performed for 15 minutes to obtain a uniform and stable milky white post-treatment solution.

[0044] Preparation method of soft and antibacterial nylon-spandex composite fabric: (1) Immerse the nylon-spandex composite fabric in the above post-treatment solution and use a two-dip and two-roll process to control the roll-off rate to 75% to ensure that the fabric is evenly coated with liquid and has no dry or wet streaks. (2) Place the impregnated fabric in a hot air pre-drying oven and control the temperature at 90℃ for 3 minutes; (3) The pre-dried fabric is sent to a double-layer hot air tenter for segmented processing: First temperature zone (cross-linking curing zone): The temperature is controlled at 120℃, the wind speed is medium to high, and the fabric running speed is controlled so that the dwell time is 1 minute. Second temperature zone (fiber setting zone): The temperature is controlled at 150℃, the wind speed is high, and the fabric running speed is controlled so that the dwell time is 30 seconds. (4) After the fabric is shaped, it is washed and dried at 100°C to obtain the finished soft antibacterial nylon-ammonia composite fabric.

[0045] Example 5 Nylon-spandex composite fabric: Warp-knitted fabric with a composition of 70wt% nylon 66 and 30wt% spandex, and a weight of 180 g / m². 2 .

[0046] Preparation of reactive organosilicon-chitosan graft copolymers: A1. Under nitrogen protection, 100 parts by weight of epoxy-terminated polydimethylsiloxane and 25 parts by weight of chitosan quaternary ammonium salt oligomer (Mn=2000 Da, degree of deacetylation ≥90%) were mixed, and dibutyltin dilaurate catalyst was added. The mixture was reacted at 82°C for 7 hours to obtain a hydroxyl-terminated grafting intermediate. A2. Add 8 parts by weight of isophorone diisocyanate to the intermediate and react at 60°C for 2 hours to introduce free isocyanate end groups. A3. Maintain 60°C, add 6.5 parts by weight of butanone oxime, react for 1.5 hours to obtain a blocked prepolymer; A4. Add a nonionic emulsifier to the prepolymer and shear it at high speed, then add deionized water dropwise for phase inversion emulsification. After vacuum distillation, a semi-transparent microemulsion with a solid content of 40% and a pH value of 6.0-6.5 is obtained.

[0047] A suitable amount of the reactive organosilicon-chitosan graft copolymer prepared in step A4 was tested by differential scanning calorimetry (DSC) according to ISO 11357-2 standard. The test conditions were a nitrogen atmosphere, a heating rate of 10℃ / min, and a temperature range of -100℃ to 50℃. The glass transition temperature Tg was measured to be -54℃.

[0048] Preparation of post-treatment solution: Add deionized water to a mixing tank equipped with a stirrer, turn on the stirrer (300 rpm), and add the components in the following proportions by mass: Reactive organosilicon-chitosan graft copolymer emulsion: 10 parts; Butanone oxime blocked hexamethylene diisocyanate (HDI) trimer aqueous dispersion (75% solids): 2.7 parts; Fatty alcohol polyoxyethylene ether: 0.3 parts; Hindered amine light stabilizer (HALS-770): 0.2 parts; Glacial acetic acid: Add an appropriate amount dropwise until the pH of the mixture stabilizes at 5.5; Deionized water: Add to a total of 100 parts by weight.

[0049] After feeding, high-speed shear emulsification (2000 rpm) was performed for 15 minutes to obtain a uniform and stable milky white post-treatment solution.

[0050] Preparation method of soft and antibacterial nylon-spandex composite fabric: (1) Immerse the nylon-spandex composite fabric in the above post-treatment solution and use a two-dip and two-roll process to control the roll-off rate to 75% to ensure that the fabric is evenly coated with liquid and has no dry or wet streaks. (2) Place the impregnated fabric in a hot air pre-drying oven and control the temperature at 90℃ for 3 minutes; (3) The pre-dried fabric is sent to a double-layer hot air tenter for segmented processing: First temperature zone (cross-linking curing zone): The temperature is controlled at 135℃, the wind speed is medium to high, and the fabric running speed is controlled so that the dwell time is 3 minutes. Second temperature zone (fiber setting zone): The temperature is controlled at 165℃, the wind speed is high, and the fabric running speed is controlled so that the dwell time is 90 seconds. (4) After the fabric is shaped, it is washed and dried at 100°C to obtain the finished soft antibacterial nylon-ammonia composite fabric.

[0051] Comparative Example 1 Based on Example 1, instead of preparing the organosilicon-chitosan graft copolymer, an equal amount of ordinary amino silicone oil emulsion was physically mixed with water-soluble chitosan oligomer, and the same blocked isocyanate crosslinking agent was added.

[0052] Comparative Example 2 Based on Example 1, the main chain uses polydimethylsiloxane (without amino, epoxy, etc.) with no reactive functional groups, and the rest is consistent with Example 1.

[0053] Comparative Example 3 Based on Example 1, without adding a blocked isocyanate crosslinking agent, a non-reactive end-group organosilicon-chitosan graft copolymer (with methyl end groups; step A2 is changed to adding 4 parts by weight of hexamethyldisiloxane to the intermediate and reacting at 80°C for 2 hours to carry out the methyl end-capping reaction and eliminate the terminal active hydroxyl groups; step A3 omits the steps of adding isocyanate and blocking agent), and the rest is consistent with Example 1.

[0054] Comparative Example 4 Based on Example 1, the segmented shaping was cancelled and replaced with single-segment shaping: the sample was directly processed at 160°C for 2 minutes and 45 seconds, while the rest remained the same as in Example 1.

[0055] Performance testing: Antibacterial properties: According to GB / T 20944.3-2008 standard, the sample and control sample were respectively placed in bacterial suspension (Staphylococcus aureus and Escherichia coli), and cultured for 24 hours under shaking conditions. The reduction rate of viable bacterial concentration was calculated. The antibacterial retention rate was determined after the sample was washed 20 times with water according to the cantilever beam washing method in GB / T 3921-2008.

[0056] Softness: The softness of the sample was evaluated according to the cantilever beam method in ASTM D1388-2018.

[0057] Test results show that all embodiments of the present invention achieve excellent initial antibacterial properties and washability. Among them, Example 1 has an initial inhibition rate of 98.7% and 99.4% against Staphylococcus aureus and Escherichia coli, respectively. After 20 washes, the antibacterial retention rate is still above 98%, and the bending length is as low as 9.2 mm, showing excellent softness. Example 2 has good initial antibacterial properties due to the low amount of finishing agent, but the washability is slightly inferior to Example 1, and the softness is slightly worse. Although Example 3 has the highest antibacterial retention rate and the smallest bending length (8.9 mm), the excessive amount may increase the cost. Examples 4 and 5 are the low and high curing temperatures, respectively, and their performance is similar to that of Example 1. Although the initial antibacterial rates of Comparative Example 1 (physical mixing), Comparative Example 2 (without epoxy grafting), and Comparative Example 3 (without active crosslinking end groups) were high (87.5%-97.5%), the antibacterial retention rate plummeted to 61.1%-73.5% after 20 washes, strongly demonstrating that the chemical bond formed by "epoxy grafting" and "blocked isocyanate crosslinking" is the core of achieving wash-resistant antibacterial properties. The antibacterial retention rate (approximately 85%) and softness (10.9 mm) of Comparative Example 4 (single-stage shaping) were both lower than those of the segmented shaping example, indicating that the segmented heating process is crucial for ensuring a thorough and uniform crosslinking reaction.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A soft, antibacterial nylon-spandex composite fabric, woven from 60-80 wt% nylon fibers and 20-40 wt% spandex fibers, characterized in that, The fabric fiber surface is coated with a functional layer, which is formed by cross-linking and curing of a reactive organosilicon-chitosan graft copolymer; The molecular structure of the reactive organosilicon-chitosan graft copolymer includes: (a) Flexible backbone: a polydimethylsiloxane backbone with reactive functional groups; wherein the reactive functional groups are selected from one or more of amino, epoxy, carboxyl, hydroxyl or mercapto groups; (b) Antibacterial side chain: a water-soluble chitosan derivative oligomer grafted onto the flexible backbone; (c) Reactive end groups: Closed isocyanate groups located at the ends of the molecular chain.

2. The soft, antibacterial nylon-spandex composite fabric according to claim 1, characterized in that, The water-soluble chitosan derivative oligomers are selected from one or more of carboxymethyl chitosan, chitosan quaternary ammonium salt, or hydroxypropyl chitosan; The number-average molecular weight (Mn) of the oligomer is 1000-5000 Da, and the degree of deacetylation is ≥85%.

3. The soft, antibacterial nylon-spandex composite fabric according to claim 1, characterized in that, The glass transition temperature Tg of the reactive organosilicon-chitosan graft copolymer is ≤ -50℃.

4. A method for preparing a soft, antibacterial nylon-spandex composite fabric as described in any one of claims 1 to 3, characterized in that, Includes the following steps: (1) Disperse the reactive organosilicon-chitosan graft copolymer, crosslinking agent, penetrant and pH adjuster in water, adjust the pH value to 5.0-6.5, and obtain the post-treatment solution; (2) The nylon-spandex composite fabric is immersed in the post-treatment solution, and after padding, the padding rate is controlled at 70%-80%, and then pre-drying and dehydration are carried out; (3) Perform segmented heat setting on the pre-baked fabric; (4) The finished product is obtained by washing and drying.

5. The method for preparing the soft, antibacterial nylon-spandex composite fabric according to claim 4, characterized in that, The post-treatment solution in step (1) consists of the following components by mass: 8-12 parts of reactive organosilicon-chitosan graft copolymer Blocked isocyanate crosslinking agent 1.5-3.0 parts 0.2-0.5 parts of fatty alcohol polyoxyethylene ether Add an appropriate amount of glacial acetic acid to adjust the pH to 5.0-6.

0. Add deionized water to bring the total to 100 parts.

6. The method for preparing the soft, antibacterial nylon-spandex composite fabric according to claim 4, characterized in that, The immersion and rolling process in step (2) is either one immersion and one rolling or two immersions and two rollings.

7. The method for preparing the soft, antibacterial nylon-spandex composite fabric according to claim 4, characterized in that, The pre-drying and dehydration temperature in step (2) is 80-100℃.

8. The method for preparing the soft, antibacterial nylon-spandex composite fabric according to claim 4, characterized in that, Step (3) describes segmented heat setting, which sequentially passes through two setting units at different temperature zones: First temperature zone: control the temperature at 120-135℃, and the processing time is 1-3 minutes; Second temperature zone: control the temperature at 150-165℃ and the processing time at 30-90 seconds.

9. The method for preparing the soft, antibacterial nylon-spandex composite fabric according to claim 4, characterized in that, In the post-treatment solution of step (1), 0.5-2.0 parts by weight of an anti-yellowing agent is also added. The anti-yellowing agent is selected from hindered amine light stabilizers, phosphite antioxidants or benzotriazole ultraviolet absorbers.

10. A seamless antibacterial bra, characterized in that: The bra's inner layer, molded cup fabric, and / or edge bonding strip are made of the soft, antibacterial nylon-spandex composite fabric as described in any one of claims 1 to 3.

Images