Antistatic finishing agent and preparation process thereof

Abstract

The invention relates to the technical field of textile chemicals, and discloses a preparation process of an antistatic finishing agent, the antistatic finishing agent is a water-based composition, and the antistatic finishing agent comprises the following components by solid content mass percentage: 1.5-2.5% of a conductive polymer; 2.0 to 4.0 percent of waterborne polyurethane containing dynamic disulfide bonds; 1.0 to 2.0 percent of a chitosan derivative; 1.5%-3.0% of a silane coupling agent; 0.5 to 1.0 percent of a photoinitiator; and the balance of water. Wherein the chitosan derivative is a host-guest compound, and a catalyst for catalyzing disulfide bond exchange is included in cyclodextrin grafted chitosan modified by photopolymerization functional groups. According to the invention, a dynamic disulfide bond network and an intelligent catalytic release system are constructed in the coating, so that damage self-repairing of an antistatic function is realized; the chitosan derivative is covalently bonded to the coating network, so that the finished fabric is endowed with durable and washable antibacterial performance.

Description

Technical Field

[0001] This invention relates to the field of textile chemicals technology, specifically to an antistatic finishing agent and its preparation process. Background Technology

[0002] Synthetic fibers such as polyester have gained widespread application in the textile industry due to their excellent physical and mechanical properties and cost advantages. However, the inherent hydrophobicity and low conductivity of these fiber materials make their surfaces highly susceptible to the generation and accumulation of static charges due to friction. Static electricity not only causes fabrics to attract dust and adhere to the body, affecting wearing comfort and aesthetics, but in certain industrial environments, electrostatic discharge can also cause combustion or explosion, posing serious safety hazards. Therefore, antistatic finishing of synthetic fiber fabrics has become a key technical aspect in improving their performance and safety. Currently, mainstream antistatic finishing technologies mainly rely on applying a functional coating to the fiber surface, which dissipates static charges through ionic or electronic conductivity mechanisms. For example, conductive polymers such as poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate (PEDOT:PSS) can be used to construct highly efficient electronic conductivity networks. However, these finishing agents usually only bond with the fiber substrate through physical adsorption or weak van der Waals forces, resulting in insufficient durability of the finishing effect. Especially after repeated household or industrial washing, the functional coating is prone to peeling, and the antistatic performance will drop sharply.

[0003] To improve coating adhesion, crosslinking agents are often introduced in existing technologies to enhance the bonding between the coating and the fiber through chemical bonding. While this improves wash resistance to some extent, it introduces new problems. The resulting crosslinked coating is often a rigid, static network structure. During use, the repeated friction, bending, and stretching of the fabric inevitably induce micro-cracks within the coating. Once formed, these cracks are permanent; they disrupt conductive pathways and damage the integrity of the conductive network, leading to a gradual and irreversible decline in antistatic properties over time.

[0004] Furthermore, with the increasing market demand for the functionality of textiles, a single antistatic function is no longer sufficient to meet the needs. Imparting additional functions such as antibacterial and anti-mite properties to fabrics has become a trend in technological development. Typically, this multifunctionality is achieved by directly and physically blending antibacterial agents, such as chitosan, into the antistatic finishing agent. However, this simple blending method also faces serious durability challenges. The antibacterial active components are easily lost during washing, causing their function to be rapidly lost, making long-term protection difficult to achieve. At the same time, traditional finishing processes often employ high-temperature heat curing, which is not only energy-intensive but may also damage heat-sensitive fibers such as spandex and high-grade silk, limiting the applicability of the technology. Summary of the Invention

[0005] The purpose of this invention is to provide an antistatic finishing agent and its preparation process, which solves the problems of antistatic finishing in terms of coating durability, functional failure after damage, and durability of multifunctional integration.

[0006] To achieve the above objectives, the present invention provides an antistatic finishing agent through the following technical solution: An antistatic finishing agent is an aqueous composition comprising, by weight percentage of solid content: 1.5-2.5% conductive polymer; 2.0-4.0% aqueous polyurethane containing dynamic disulfide bonds; 1.0-2.0% chitosan derivative; 1.5-3.0% silane coupling agent; 0.5-1.0% photoinitiator; and the balance being water.

[0007] In one specific embodiment, the conductive polymer is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, CAS (Chemical Abstracts Service) registration number: 155090-83-8. This component constructs a conductive network in the final coating to achieve antistatic properties.

[0008] In one specific embodiment, the aqueous polyurethane containing dynamic disulfide bonds has a disulfide bond structure in its molecular backbone or side chains. This structure, after being broken by external forces, possesses the ability to reconnect and form chemical bonds, providing a repairable matrix for the final coating.

[0009] In one specific embodiment, the chitosan derivative is a host-guest complex. In this complex, the guest molecule is a catalyst for disulfide bond exchange reactions, and the host molecule is chemically modified chitosan. This structure encapsulates the catalyst molecule within a specific cavity of the host molecule, allowing it to remain inactive unless excited under specific conditions.

[0010] In a preferred embodiment, the host molecule is chitosan grafted with cyclodextrin, and the guest molecule is imidazole or a derivative thereof. The cyclodextrin molecule has a cavity structure that is hydrophobic on the inside and hydrophilic on the outside, enabling it to encapsulate the imidazole molecule within it through non-covalent bonding. When the final coating structure is intact, the imidazole molecule is bound within the cyclodextrin cavity; when the coating develops microcracks due to mechanical damage, the change in the local environment weakens the host-guest interaction, causing the imidazole molecule to be released from the cavity and move to the vicinity of the broken disulfide bond, catalyzing the reversible exchange reaction of the disulfide bond, thereby repairing the coating structure.

[0011] In another preferred embodiment, the chitosan derivative further comprises photopolymerizable functional groups in its molecular structure. In a more preferred embodiment, the functional group is a methacrylate group. The presence of this functional group enables the chitosan derivative to copolymerize with other components in the system containing photopolymerizable functional groups under photoinitiation conditions, thereby becoming part of the final cured coating network framework in the form of covalent bonds.

[0012] In another preferred embodiment, the silane coupling agent is a silane containing functional groups capable of photopolymerization. In a more preferred embodiment, the silane coupling agent is 3-(methacryloyloxy)propyltrimethoxysilane. This coupling agent molecule has a dual function: the trimethoxysilane group at one end can hydrolyze to generate silanol groups, which then undergo dehydration condensation with hydroxyl groups on the surface of fibers or fabrics to form stable -Si-OC- covalent bonds, firmly anchoring the entire coating to the substrate surface; the methacrylate group at the other end can participate in free radical polymerization under light irradiation, becoming part of the crosslinking network.

[0013] A second aspect of the present invention provides a process for preparing an antistatic finishing agent, used to prepare the antistatic finishing agent described in any of the foregoing embodiments, characterized by comprising the following steps: Step 1: Mix the conductive polymer, waterborne polyurethane containing dynamic disulfide bonds, chitosan derivative, silane coupling agent and photoinitiator in an aqueous medium to obtain the finishing agent working solution. Step 2: Treat the fibers or fabrics with the finishing agent working solution; Step 3: Use ultraviolet light to irradiate the treated fibers or fabrics to cure the finishing agent.

[0014] In one specific embodiment, the chitosan derivative described in step one is prepared in advance by the following steps: first, cyclodextrin molecules are grafted onto the chitosan molecular chain through a chemical reaction; then, functional groups capable of photopolymerization are introduced into the molecular structure of the resulting grafted product; finally, a catalyst for catalyzing disulfide bond exchange is encapsulated in the cyclodextrin cavity on the product molecule through host-guest interaction.

[0015] In a preferred embodiment, step three, before ultraviolet irradiation of the fiber or fabric, further includes a pretreatment step: the fiber or fabric treated in step two is left to stand for 5-15 minutes in a dark environment at a temperature of 10-25°C and a relative humidity of 70-90%. The purpose of this pretreatment step is to provide sufficient hydrolysis conditions and time for the trimethoxysilane groups of the silane coupling agent, converting them into highly reactive silanol groups and allowing for orderly pre-adsorption on the fiber or fabric surface. This process facilitates the formation of a denser and stronger covalent bond between the silane coupling agent and the substrate in the subsequent photocuring step. The subsequent ultraviolet irradiation step then triggers a rapid polymerization reaction of all photopolymerizable functional groups within the system, forming a cross-linked interpenetrating polymer network coating chemically bonded to the substrate surface.

[0016] In summary, the present invention has at least one of the following beneficial technical effects: 1. This invention, through the provided antistatic finishing agent, introduces a dynamic disulfide bond structure into the waterborne polyurethane matrix, enabling the final coating to possess self-healing capabilities. When the coating develops micro-cracks due to external mechanical forces, the broken disulfide bonds can reconnect under specific conditions, restoring the integrity of the conductive network. Compared to the static, irreversible cross-linking structure in existing technologies, this invention significantly improves the service life of the antistatic coating and its performance reliability during long-term friction and washing processes.

[0017] 2. This invention achieves long-lasting antibacterial function by covalently bonding chitosan derivatives as structural units into the cross-linked network. As a natural biomass material, chitosan's antibacterial properties are firmly locked within the coating framework, avoiding the problem of easy loss of traditional physically added antibacterial agents during washing. This endows textiles with long-lasting, wash-resistant hygienic protective properties and increases the added value of the product.

[0018] 3. This invention achieves on-demand catalyst release by encapsulating imidazole molecules that catalyze disulfide bond exchange within a cyclodextrin-grafted chitosan derivative. This design avoids unnecessary reactions or degradation of the catalyst when the coating is intact, releasing it only to perform its repair function when the coating is damaged or the local microenvironment is altered. This significantly improves the efficiency and precision of the self-healing reaction and solves the technical challenge of controlling catalytic activity in traditional self-healing systems.

[0019] 4. This invention utilizes an ultraviolet curing process, which allows the entire curing process to be completed instantaneously at room temperature. This not only significantly reduces energy consumption and shortens the production cycle, but also avoids the potential damage to heat-sensitive fibers (such as spandex and high-grade silk) caused by high-temperature baking in traditional thermosetting processes. This broadens the range of fabrics suitable for antistatic finishing technology and enhances process adaptability. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to embodiments, comparative examples and test examples.

[0021] Unless otherwise stated, the raw materials and reagents used in the following examples are commercially available products or can be prepared by known methods.

[0022] Example 1: This embodiment describes the preparation process of the core functional components used in the formulation of subsequent finishing agents. Step 1.1: Synthesis of Cyclodextrin-Grafted Chitosan (CD-CS) In a 500 mL three-necked flask, 10.0 g of chitosan (CS) was added to 400 mL of a 2.5% aqueous acetic acid solution and magnetically stirred at 40 °C until completely dissolved. In another beaker, 65.0 g of β-cyclodextrin (β-CD) was dissolved in 120 mL of a 2.0 mol / L aqueous sodium hydroxide solution and cooled to below 5 °C in an ice-water bath. A 100 mL acetone solution containing 20.0 g of p-toluenesulfonyl chloride (TsCl) was slowly added dropwise to this β-CD solution. After the addition was complete, the reaction was continued at 5 °C for 4 hours to obtain a monotoluenesulfonyl-β-cyclodextrin (OTs-CD) solution.

[0023] The prepared OTs-CD solution was slowly added dropwise to the chitosan solution at 25°C using a constant-pressure dropping funnel. After the addition was complete, the reaction system was heated to 60°C under nitrogen protection and reacted for 24 hours. After the reaction was completed, the mixture was cooled to room temperature, and the pH was adjusted to 9.0 with 2.0 mol / L sodium hydroxide solution, resulting in the precipitation of a white solid. The precipitate was collected by suction filtration and washed repeatedly with deionized water and ethanol until the washing solution was neutral. The obtained solid was dried in a vacuum drying oven at 60°C for 24 hours to obtain a white powdery product, CD-CS.

[0024] Step 1.2: Synthesis of methacrylated cyclodextrin-grafted chitosan (GMA-CD-CS) In a 250 mL three-necked flask, 5.0 g of the CD-CS powder obtained in Step 1.1 was dispersed in 150 mL of N,N-dimethylformamide (DMF) and sonicated for 30 minutes to ensure uniform dispersion. 0.08 g of hydroquinone was added to the system as a polymerization inhibitor. Under nitrogen protection and mechanical stirring, the system was heated to 70 °C, and 2.0 g of glycidyl methacrylate (GMA) was slowly added dropwise using a syringe pump. After the addition was complete, the reaction was continued at this temperature for 10 hours. After the reaction was complete, the mixture was cooled to room temperature and precipitated in 1000 mL of acetone. The precipitate was collected by filtration, washed three times with acetone, and then dried in a vacuum drying oven at 40 °C for 24 hours to obtain a pale yellow powder product, GMA-CD-CS.

[0025] Step 1.3: Preparation of imidazole inclusion complex In a 250 mL brown beaker, disperse 2.0 g of the GMA-CD-CS powder obtained in step 1.2 in 100 mL of deionized water. Separately dissolve 0.4 g of imidazole in 10 mL of deionized water. Add the imidazole solution to the GMA-CD-CS dispersion, wrap the beaker with aluminum foil to protect it from light, and magnetically stir at 25 °C for 48 hours to allow the imidazole molecules to fully form a host-guest inclusion structure with the cyclodextrin cavity. The resulting mixture is the aqueous stock solution of the core functional component (Imidazole@GMA-CD-CS), with a solid content of approximately 2.1 wt%, and is used directly in subsequent steps.

[0026] Example 2: This embodiment describes the complete process of using the core functional components prepared in Example 1 to formulate the final antistatic finishing agent and apply it to the fabric.

[0027] Step 2.1: Preparation of the finishing agent working solution In a 250mL beaker, add the components in the following order and by weight: Deionized water: 71.3g; Poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate, CAS No.: 155090-83-8, aqueous dispersion (PEDOT: PSS, solid content 3.5%): 57.1g; Waterborne polyurethane prepolymer containing dynamic disulfide bonds (-SS-WPU, solid content 30.0%): 10.0g; Synthesis of waterborne polyurethane prepolymer containing dynamic disulfide bonds (-SS-WPU): raw material: Isophorone diisocyanate (IPDI), CAS: 4098-71-9; Polyethylene glycol (PEG), number average molecular weight Mn = 2000, CAS: 25322-68-3; Bis(2-hydroxyethyl)disulfide (HEDS), CAS: 5240-54-0; Dimethylolpropionic acid (DMPA), CAS: 4767-03-7; Triethylamine (TEA), CAS: 121-44-8; Acetone, CAS: 67-64-1; Dibutyltin dilaurate (DBTDL), CAS: 77-58-7; In a 500 mL four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, and nitrogen inlet, add 40.0 g of polyethylene glycol (PEG, 0.02 mol) and 3.08 g of bis(2-hydroxyethyl) disulfide (HEDS, 0.02 mol). Dehydrate under vacuum at 80 °C for 2 hours.

[0028] The reaction system was cooled to 60°C, and 5.36 g of dimethylolpropionic acid (DMPA, 0.04 mol) and 100 mL of anhydrous acetone were added. The mixture was stirred until the DMPA was completely dissolved. Subsequently, 4 drops of dibutyltin dilaurate (DBTDL) were added as a catalyst.

[0029] Under nitrogen protection, the system was heated to 75°C. 19.98 g of isophorone diisocyanate (IPDI, 0.09 mol) was slowly added dropwise over 1 hour using a constant-pressure dropping funnel. After the addition was complete, the reaction was continued at 75°C for 4 hours. Samples were taken periodically, and the content of -NCO groups in the system was determined using the di-n-butylamine titration method until it reached or slightly fell below the theoretically calculated value.

[0030] The reaction system was cooled to 50°C, and 4.04 g of triethylamine (TEA, 0.04 mol) was added. The mixture was stirred at 50°C for 30 minutes to neutralize the carboxyl groups of DMPA.

[0031] The polyurethane prepolymer acetone solution obtained above was added to 180 mL of deionized water within 30 minutes under high-speed shear stirring (1000 rpm) for emulsification and dispersion. After dispersion, the acetone was removed by vacuum evaporation using a rotary evaporator at 50 °C.

[0032] The final product was a semi-transparent, slightly bluish aqueous dispersion of a polyurethane prepolymer containing dynamic disulfide bonds, with a solid content of 30.0 wt%. This aqueous dispersion is the -SS-WPU used in the examples.

[0033] The stock solution of Imidazole@GMA-CD-CS prepared in Example 1 (solid content approximately 2.1%): 71.4 g; (Methacryloxy)propyltrimethoxysilane, CAS No.: 2530-85-1 (MPTMS): 2.2g; 2-Hydroxy-2-methyl-1-phenyl-1-propanone: 0.8g.

[0034] Turn on the magnetic stirrer (250 rpm) and mix for 60 minutes at room temperature to obtain a homogeneous and stable blue-black finishing agent working solution.

[0035] Step 2.2: Padded treatment of the fabric Take a pre-cleaned and dried polyester knitted fabric sample and immerse it completely in the finishing agent working solution prepared in step 2.1 for 2 minutes. Then, pass the fabric through a laboratory two-roller padding machine to purge the liquid, setting the padding machine pressure to 0.25 MPa, so that the liquid retention rate of the fabric sample is 80 ± 2%.

[0036] Step 2.3: Static pre-hydrolysis Lay the damp fabric treated in step 2.2 flat on a PTFE mesh and immediately place it in a constant temperature and humidity chamber. Set the chamber conditions to: temperature 22℃, relative humidity 80%, and let it stand in a dark environment for 10 minutes.

[0037] Step 2.4: UV curing and post-treatment The pre-hydrolyzed fabric was removed from the constant temperature and humidity chamber, laid flat on a quartz plate, and placed in a UV curing chamber. It was then irradiated using a high-pressure mercury lamp under a nitrogen atmosphere. The distance between the light source and the fabric surface was set to 12 cm, and the UV irradiation intensity was 100 mW / cm². 2 The total irradiation time was 120 seconds. After light curing, the fabric was placed in an oven at 80°C for 10 minutes to remove residual moisture, obtaining a finished fabric sample. The sample was then conditioned under standard atmospheric conditions for 24 hours before use.

[0038] Comparative Example 1: Compared with Example 2, the difference is that in the preparation of the finishing agent working solution in step 2.1, 10.0g of conventional waterborne polyurethane prepolymer (WPU, solid content 30.0%) is used to replace an equal mass of waterborne polyurethane prepolymer (-SS-WPU) containing dynamic disulfide bonds, while the other components and preparation process are the same.

[0039] Comparative Example 2: Compared with Example 2, the difference is that in the preparation of the finishing agent working solution in step 2.1, the Imidazole@GMA-CD-CS stock solution prepared in Example 1 is not used. Instead, GMA-CD-CS with equivalent solid content (i.e. the product of step 1.2) and 0.4g of imidazole powder are added for physical blending. The remaining components and preparation process are the same.

[0040] Comparative Example 3: Compared with Example 2, the difference is that in the preparation of the finishing agent working solution in step 2.1, the Imidazole@GMA-CD-CS stock solution prepared in Example 1 is not used. Instead, chitosan (CS) powder with equivalent solid content without any chemical modification is directly added. The other components and preparation process are the same.

[0041] Comparative Example 4: Compared with the finishing process of Example 2, the difference is that after the fabric sample is impregnated in step 2.2, the static pre-hydrolysis process in step 2.3 is omitted, and the ultraviolet curing in step 2.4 is carried out directly, while the other conditions are the same.

[0042] Comparative Example 5: These are raw polyester knitted fabric samples that have not undergone any chemical finishing, serving as a benchmark for various performance tests.

[0043] Test Example 1: The fabric samples prepared in Example 2 and Comparative Examples 1-5 were cut into 120mm × 120mm sizes. All samples were conditioned for 24 hours in a constant temperature and humidity environment (temperature 23±1℃, relative humidity 50±5%). The resistivity of the fabric surface was measured using a high resistivity meter (e.g., ZC36 type) equipped with a ring electrode. Five measurements were taken at different locations for each sample, and the geometric mean was taken as the final result. This is the initial surface resistivity.

[0044] Subsequently, each sample was repeatedly washed according to procedure 2A of the AATCC 61-2009 test method. After 10, 20, and 30 cumulative washes, the samples were removed, dried in a 60°C oven, and then conditioned again in the same constant temperature and humidity environment for 24 hours. After conditioning, the surface resistivity was measured again using the same method.

[0045] Table 1. Surface resistivity test results of different fabric samples. sample initial state After washing 10 times After washing 20 times After washing 30 times Example 2 8.3 x 10 7 ]] <![CDATA[2.6×10 8 ]]> <![CDATA[5.9×10 8 ]]> <![CDATA[9.4×10 8 ]]> Comparative Example 1 <![CDATA[8.8×10 7 ]]> <![CDATA[4.5×10 8 ]]> <![CDATA[1.1×10 9 ]]> <![CDATA[2.7×10 9 ]]> Comparative Example 2 <![CDATA[9.1×10 7 ]]> <![CDATA[5.2×10 8 ]]> <![CDATA[1.5×10 9 ]]> <![CDATA[3.1×10 9 ]]> Comparative Example 3 <![CDATA[8.9×10 7 ]]> <![CDATA[6.8×10 8 ]]> <![CDATA[2.2×10 9 ]]> <![CDATA[4.8×10 9 ]]> Comparative Example 4 <![CDATA[8.5×10 7 ]]> <![CDATA[9.1×10 8 ]]> <![CDATA[5.3×10 9 ]]> <![CDATA[1.6×10 10 ]]> Comparative Example 5 <![CDATA[>1.0×10 13 ]]> <![CDATA[>1.0×10 13 ]]> <![CDATA[>1.0×10 13 ]]> <![CDATA[>1.0×10 13 ]]>

[0046] As shown in Table 1, compared with the untreated Comparative Example 5, the treated Samples of Example 2 and Comparative Examples 1-4 all achieved lower initial surface resistivity. This indicates that the conductive polymer PEDOT:PSS in the finishing agent formed an effective conductive network on the fabric surface. Compared with the sample of Comparative Example 4, the increase in surface resistivity of Sample 2 after multiple washes was significantly slower. This phenomenon is due to the static pre-hydrolysis step included in the preparation process of Example 2, which promoted the formation of a more stable chemical bond between the silane coupling agent MPTMS and the fiber substrate, thereby improving the adhesion of the entire functional coating to the fabric surface and effectively resisting physical peeling during the washing process.

[0047] Comparing the test data of Example 2 and Comparative Example 1, their initial performance was similar. However, with increasing washing cycles, the antistatic performance of Comparative Example 1 degraded faster than that of Example 2. This is because the microcracks generated in the conventional polyurethane matrix used in Comparative Example 1 under repeated mechanical stress are irreversible, and the continuously accumulating damage disrupts the continuity of the conductive network. In contrast, the coating matrix of Example 2 contains dynamic disulfide bonds. This structure has the ability to break and reassemble under stress, which can repair the microscopic damage generated during washing, thereby better maintaining the integrity of the conductive pathway on a macroscopic level, resulting in superior antistatic durability.

[0048] Furthermore, the comparison results between Example 2 and Comparative Examples 2 and 3 show that integrating functional components into the polymer network framework through chemical bonding yields a more uniform and stable coating structure than simple physical blending. In Example 2, the chitosan derivative is covalently bonded to the crosslinked network through its methacrylate groups, forming a denser and more complete coating structure. This structural integrity is the physical basis for ensuring the coating's wash resistance and stable performance of its various functions.

[0049] Test Example 2: The fabric samples prepared in Examples 2, 3, and 5 were cut into 0.75 ± 0.05 g pieces. The test bacteria used were Staphylococcus aureus and Escherichia coli. Each fabric sample was placed in a conical flask containing 70 mL of buffered saline solution, and 1.0 mL of bacterial suspension with a concentration of (1-5) × 10⁵ CFU / mL was added. The conical flasks were placed in a constant temperature shaking incubator and shaken at 150 rpm for 18 hours at 24 ± 1 °C. After shaking, the solutions in each conical flask were serially diluted, and the viable bacteria were counted using the plate count method to calculate the inhibition rate. This was the initial antibacterial performance test.

[0050] Subsequently, another batch of identical fabric samples was washed 30 times according to procedure 2A of the AATCC 61-2009 test method. After washing, the samples were dried and their antibacterial rate was tested again using the same method described above.

[0051] Table 2. Antibacterial rate test results of different fabric samples Table 2 shows that the samples of Example 2 and Comparative Example 3 exhibited high inhibition rates against Staphylococcus aureus and Escherichia coli in their initial state, while the untreated Comparative Example 5 sample showed no antibacterial activity. After 30 standard washes, the sample of Example 2 still maintained an inhibition rate higher than 98%, while the inhibition rate of the sample of Comparative Example 3 decreased significantly. This result indicates that the antibacterial function obtained by the sample of Example 2 has significant wash resistance and durability.

[0052] The reason why the sample in Example 2 can maintain long-lasting antibacterial properties lies in the molecular structure design of the core functional component in the finishing agent. Methacrylate groups are pre-introduced onto the chitosan derivative molecule in this component. These groups participate in the free radical polymerization reaction as reactive sites during the UV curing step. This process allows the antibacterial chitosan units to become part of the final three-dimensional cross-linked network framework of the coating through stable covalent bonds, thus being firmly anchored to the fiber surface.

[0053] In contrast, the antibacterial component used in Comparative Example 3 was ordinary chitosan powder without chemical modification, which was bound to the coating matrix and fibers only through physical adsorption or mechanical encapsulation. This non-chemical bonding is weak, and under the mechanical agitation and water rinsing of repeated washing, chitosan particles easily detach from the coating and are lost, resulting in a rapid decline in its antibacterial function with increasing washing cycles. Therefore, covalently bonding functional units to the coating network is an effective technical approach to achieve functional durability.

[0054] Test Example 3: 1. Testing Methods and Procedures Fabric samples prepared according to Example 2 and Comparative Example 1 were cut into 50mm × 50mm sizes. The samples were conditioned under standard conditions for 24 hours. The initial surface resistivity of the central region of the sample was measured using a high-resistivity meter equipped with a dual-probe electrode.

[0055] Subsequently, using a scalpel blade, a scratch approximately 1.5 cm long and deep enough to just penetrate the coating was made perpendicularly in the central test area of ​​the sample, along the direction of the probe measurement. The surface resistivity of the scratched area was then measured again immediately.

[0056] The scratched sample was heat-treated in a constant temperature oven at 60±2℃ for 30 minutes. After treatment, the sample was removed and allowed to return to room temperature, then conditioned again under standard conditions for 4 hours. Finally, the surface resistivity of the repaired sample was measured in the same scratched area.

[0057] Table 3. Test results of damage and repair of electrical conductivity of different fabric samples sample initial state After injury After repair Example 2 <![CDATA[8.6×10 7 ]]> <![CDATA[>1.0×10 13 ]]> <![CDATA[7.1×10 8 ]]> Comparative Example 1 <![CDATA[8.9×10 7 ]]> <![CDATA[>1.0×10 13 ]]> <![CDATA[>1.0×10 13 ]]> As shown in Table 3, both Sample 2 and Comparative Example 1 exhibited low surface resistivity in their initial state. After being subjected to mechanical scratches, the resistivity of both samples increased sharply to the insulation level, indicating that the conductive network structure on their surfaces was damaged. After a predetermined heat treatment process, the surface resistivity of Sample 2 decreased significantly, recovering to a level close to its initial value, while the resistivity of Sample 1 remained unchanged, maintaining its insulating state. This result objectively confirms that the coating of Sample 2 possesses a self-healing capability with conductive properties.

[0058] The restoration of electrical properties exhibited by the sample in Example 2 is physically based on the repair of the coating matrix structure. The aqueous polyurethane matrix of this coating contains dynamic disulfide bonds. When mechanical forces cause the coating to crack and the polymer chains to break, heat treatment provides the necessary energy for the reversible exchange reaction of the disulfide bonds. Under thermal drive, the broken disulfide bonds on both sides of the crack interface can reform covalent bonds, allowing the polymer network to reconnect, thereby repairing the physical cracks and restoring the previously interrupted conductive polymer pathways.

[0059] The achievement of this repair process also benefits from the host-guest complex designed in the finishing agent. Imidazole molecules, used to catalyze disulfide bond exchange, are encapsulated within the cyclodextrin cavity. When cracks occur, the altered local environment causes them to be released from the cavity into the damaged area, locally catalyzing the recombination of disulfide bonds. In contrast, the coating in Comparative Example 1 uses conventional polyurethane without disulfide bonds, whose molecular chain breakage is irreversible. Therefore, even under the same heat treatment conditions, its physical damage cannot be repaired, the conductive network remains open-circuited, and its antistatic function cannot be restored.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An antistatic finishing agent, characterized in that, Based on the percentage of solid content by mass, it contains the following components: Conductive polymer: 1.5-2.5%; Waterborne polyurethane containing dynamic disulfide bonds: 2.0-4.0%; Chitosan derivatives: 1.0-2.0%; Silane coupling agent: 1.5-3.0%; Photoinitiator: 0.5-1.0%; The remainder is water.

2. The antistatic finishing agent according to claim 1, characterized in that, The conductive polymer is poly(3,4-ethylenedioxythiophene)-polystyrene sulfonate.

3. The antistatic finishing agent according to claim 1, characterized in that, The chitosan derivative is a host-guest complex, wherein the guest molecule is a catalyst for catalyzing disulfide bond exchange, and the host molecule is modified chitosan.

4. The antistatic finishing agent according to claim 3, characterized in that, The host molecule is chitosan grafted with cyclodextrin, and the guest molecule is imidazole or its derivative.

5. The antistatic finishing agent according to claim 1, characterized in that, The molecular structure of the chitosan derivative also contains functional groups capable of photopolymerization.

6. The antistatic finishing agent according to claim 1, characterized in that, The functional group capable of photopolymerization is a methacrylate group.

7. The antistatic finishing agent according to claim 1, characterized in that, The silane coupling agent is a silane containing a functional group capable of photopolymerization, and the silane is 3-propyltrimethoxysilane.

8. A process for preparing an antistatic finishing agent, used to prepare an antistatic finishing agent according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Mix the conductive polymer, waterborne polyurethane containing dynamic disulfide bonds, chitosan derivative, silane coupling agent and photoinitiator in an aqueous medium to obtain the finishing agent working solution. Step 2: Treat the fibers or fabrics with the finishing agent working solution; Step 3: Use ultraviolet light to irradiate the treated fibers or fabrics to cure the finishing agent.

9. The process for preparing an antistatic finishing agent according to claim 8, characterized in that, The chitosan derivative mentioned in step one is prepared in advance through the following steps: Grafting cyclodextrin onto chitosan molecular chains; Introduce functional groups capable of photopolymerization into the molecular structure of the grafted product; The catalyst that catalyzes disulfide bond exchange is incorporated into the graft product through host-guest interaction.

10. The process for preparing an antistatic finishing agent according to claim 8, characterized in that, Step three includes a pretreatment step before irradiating the fibers or fabrics with ultraviolet light: the treated fibers or fabrics are left to stand for 5-15 minutes in a dark environment with a temperature of 10-25℃ and a relative humidity of 70-90%.

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