After-finishing process for improving light color fastness of fabric

Abstract

The invention discloses an after-finishing process for improving the light color fastness of a fabric. The after-finishing process comprises the following steps: S1, preparing a modified fabric; s2, adding epoxy modified waterborne polyurethane emulsion, modified titanium dioxide, 2-ethyl-4-methylimidazole and fatty alcohol-polyoxyethylene ether into deionized water, and uniformly stirring, so as to obtain finishing liquid; and S3, carrying out padding treatment on the pretreated fabric in the finishing liquid, and carrying out post-treatment on the padded fabric. According to the process, the surface of the polyester fabric is modified, a sulfydryl functional group with high reaction activity is introduced to the polyester fabric, modified titanium dioxide is added at the same time, and in the finishing process, a highly stable three-dimensional network coating among the fabric, polyurethane and titanium dioxide is formed under high-temperature baking through the bridging effect of epoxy modified waterborne polyurethane; and the added modified titanium dioxide not only effectively inhibits the photodegradation of the dye due to illumination and ultraviolet radiation, but also remarkably improves the illumination color fastness of the fabric.

Description

Technical Field

[0001] This invention belongs to the field of fabric finishing technology, specifically relating to a finishing process for improving the light fastness of fabrics. Background Technology

[0002] Polyester (polyethylene terephthalate) fiber is widely used in the textile and apparel industry due to its excellent physical and mechanical properties, dimensional stability, and ease of care. However, the regular molecular structure, high crystallinity, and lack of active functional groups on the surface of polyester fiber result in poor dyeing performance. To obtain vibrant colors, disperse dyes are typically used for polyester dyeing, and the process is carried out under high temperature and high pressure or in the presence of a carrier.

[0003] Although disperse dyes are the main dyes for polyester, their small molecular weight means they bind to polyester fibers primarily through physical interactions such as van der Waals forces and dipole interactions, lacking chemical bonds. Furthermore, the molecular structure of disperse dyes typically contains chromophores such as azo or anthraquinone groups. These structures are prone to photo-oxidation or photo-reduction reactions under prolonged exposure to sunlight, especially ultraviolet light, leading to the destruction of the chromophore system and causing fading or discoloration of the fabric. Therefore, polyester fabrics, especially those dyed in bright or light colors, generally have poor lightfastness, which significantly limits their application in fields requiring high light resistance, such as outdoor clothing, automotive interiors, and curtains.

[0004] To improve the light fastness of polyester fabrics, the industry typically employs finishing methods. One common technique is treatment with UV absorbers. For example, UV absorbers such as benzotriazoles or benzophenones are applied to the fabric surface through padding or coating. However, these small-molecule UV absorbers only undergo physical adsorption with the fibers, resulting in poor binding strength and easy loss during wear and washing, leading to a lack of long-lasting lightfastness. Furthermore, during finishing, these auxiliaries can easily migrate from the finishing solution to the fabric surface, causing uneven distribution and affecting the finishing effect and fabric appearance. Another technique involves coating with film-forming resins (such as polyurethane or acrylates) to physically encapsulate dye molecules on the fiber surface, isolating them from contact with light and oxygen. However, this method has many drawbacks: First, the adhesion between ordinary resin coating and chemically inert polyester surface is poor, and the coating itself is easy to peel off after repeated washing and rubbing, resulting in a decrease in color fastness; Second, an excessively thick resin coating will seriously affect the original softness and breathability of the fabric, making it stiff and stuffy; Finally, the simple resin film has limited ability to shield ultraviolet rays and cannot fundamentally prevent high-energy photons from damaging dye molecules.

[0005] Therefore, developing a finishing technology that can firmly bond functional coatings to the surface of polyester fibers, significantly and effectively improving light fastness without sacrificing the original excellent hand feel and style of the fabric, is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a finishing process to improve the light fastness of fabrics.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric modification: Add the dyed polyester fabric to a sodium hydroxide solution, then add the modifier and impregnate it. After the treatment, filter and wash it, then add it to an ethanol aqueous solution, add γ-mercaptopropyltrimethoxysilane, stir and react. After the reaction is complete, take it out and dry it to obtain the modified fabric. S2. Preparation of finishing solution: Add epoxy-modified waterborne polyurethane emulsion, modified titanium dioxide, 2-ethyl-4-methylimidazolium, and fatty alcohol polyoxyethylene ether to deionized water and stir evenly to obtain the finishing solution. S3. Fabric finishing: The pre-treated fabric is immersed in the finishing solution and then post-treated.

[0008] Preferably, the modifier in step S1 is prepared as follows: by weight, 20-30 parts of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 15-25 parts of benzyl alcohol, 10-20 parts of sodium polyacrylate, and 2-3 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 40-60°C for 30-50 minutes to obtain the modifier.

[0009] In this invention, the prepared modifier exhibits functional synergy and additive effects among its raw materials. Ethylene glycol, as the main solvent and basic swelling agent, possesses excellent affinity and penetration ability for polyester, wetting and initially penetrating the fiber. Benzyl alcohol enables polymer chain segments to begin moving at lower temperatures, further intensifying the movement of fiber chain segments and making the fiber structure more porous. Tetrabutylammonium bromide, as a phase transfer catalyst, not only expands the polymer chain with its large cations, achieving deep swelling, but also carries alkaline ions into the hydrophobic fiber interior, greatly improving the efficiency and uniformity of subsequent alkaline hydrolysis reactions. Furthermore, sodium polyacrylate in the system acts as a dispersant, ensuring the stability of each component and preventing re-contamination, while disodium ethylenediaminetetraacetate eliminates potential interference by chelating hard ions in water, ensuring the stability and efficiency of the entire modification process. Through the synergistic chemical and physical effects of its components, this modifier achieves efficient and uniform swelling of polyester fibers under mild conditions, providing the necessary prerequisite for the subsequent precise introduction of active sites on the fiber surface.

[0010] Preferably, in step S1, the mass concentration of the sodium hydroxide solution is 0.5-1%, the ratio of the polyester fabric to the sodium hydroxide solution is 1:20-30, the amount of the modifier added is 1-2% of the mass of the polyester fabric, and the immersion treatment temperature is 50-60℃ for 30-40 minutes.

[0011] In this invention, a novel synergistic effect of sodium hydroxide solution and a specially designed penetrating swelling modifier is employed to modify the surface of polyester under mild temperature conditions. During this process, the modifier first penetrates and swells the amorphous regions of the fiber, opening channels for the uniform action of the alkali agent and ensuring that the hydrolysis reaction is confined to the outermost layer of the fiber. Sodium hydroxide then performs limited hydrolysis of the surface ester bonds, not only chemically introducing the necessary active hydroxyl functional groups for subsequent reactions into the fiber, but also physically microscopically etching the smooth fiber surface, forming nanoscale pits and grooves. This process... The surface, modified by both chemical and physical means, provides reaction sites for the subsequent chemical bonding of silane coupling agents through the newly formed hydroxyl groups. On the other hand, the rough structure generated by micro-etching greatly increases the specific surface area of ​​the fiber, providing a strong mechanical locking force for the finishing agent after film formation. Through the dual mechanism of chemical bonding and physical anchoring, the problem of poor bonding strength caused by traditional resin finishing relying solely on physical coating is fundamentally solved, laying a solid foundation for the final formation of a highly durable functional coating. At the same time, because its action is mild and controllable, it avoids damage to the strength of the main fabric.

[0012] Preferably, in step S1, the volume ratio of ethanol to water in the ethanol-water solution is 90-95:5-10, the amount of γ-mercaptopropyltrimethoxysilane added is 4-5% of the mass of the polyester fabric, and the temperature of the stirring reaction is 60-70℃, and the time is 2-3h.

[0013] Preferably, in step S2, the amount of each raw material in the finishing liquid by weight is: 50-60 parts of epoxy-modified waterborne polyurethane emulsion, 5-8 parts of modified titanium dioxide, 0.5-0.8 parts of 2-ethyl-4-methylimidazole, 1-2 parts of fatty alcohol polyoxyethylene ether, and 200 parts of deionized water.

[0014] In this invention, the finishing liquid is based on epoxy-modified waterborne polyurethane emulsion as the base resin. After drying, it forms a continuous, transparent film on the fabric surface and between the fiber interlacing points. This film not only provides initial isolation between the fibers and dyes and the external environment, but more importantly, the epoxy groups carried on its molecular chain provide key active sites for subsequent chemical bonding with modified titanium dioxide. Modified titanium dioxide is a core functional additive for achieving efficient light protection. It possesses the excellent UV shielding capability of the titanium dioxide core and, through surface modification, achieves good compatibility with the waterborne polyurethane system. Crucially, the amino functional groups grafted onto its surface undergo an efficient ring-opening addition reaction with the epoxy groups on the polyurethane molecular chain under high-temperature baking conditions. The reaction causes titanium dioxide nanoparticles to be firmly locked in the polyurethane film network by covalent bonds, fundamentally solving the problem of traditional UV shielding agents relying on physical adsorption and being prone to detachment and failure. 2-Ethyl-4-methylimidazole, as a catalyst, can significantly promote the cross-linking reaction of amino, thiol and epoxy groups within a set time, enabling it to proceed rapidly, efficiently and as completely as possible. Fatty alcohol polyoxyethylene ether, as a nonionic surfactant, reduces the surface tension of water, allowing the finishing solution to quickly and evenly wet the fabric surface and penetrate into the fiber interior. This ensures that the functional additives not only remain on the fabric surface but also penetrate into the gaps between fibers, thereby forming a comprehensive and three-dimensional protective layer, ensuring the uniformity of the final fabric appearance and the durability of its functions.

[0015] Preferably, the method for preparing the modified titanium dioxide in step S2 is as follows: Titanium dioxide was added to an aqueous ethanol solution, followed by the addition of vinyltriethoxysilane, and the mixture was heated to react. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, the ethylene-modified titanium dioxide was added to DMF, followed by the addition of 5-amino-2-mercaptobenzimidazole and azobisisobutyronitrile, and the mixture was subjected to a constant-temperature reaction. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0016] Preferably, the volume ratio of ethanol to water in the ethanol-water solution is 4-5:1, the mass ratio of titanium dioxide to vinyltriethoxysilane is 100:7-10, the heating reaction temperature is 50-60℃, and the time is 4-6h; the mass ratio of ethyleneized titanium dioxide, 5-amino-2-mercaptobenzimidazole, and azobisisobutyronitrile is 100:8-11:0.1-0.2, the isothermal reaction temperature is 70-80℃, and the time is 3-4h.

[0017] In this invention, a reactive double bond is introduced into titanium dioxide by reacting vinyltriethoxysilane with titanium dioxide. Subsequently, 5-amino-2-mercaptobenzimidazole is introduced into titanium dioxide through a free radical addition reaction between the double bond and the thiol group in 5-amino-2-mercaptobenzimidazole. The resulting modified titanium dioxide exhibits a high degree of spatial synergy between the UV shielding effect of the core titanium dioxide and the free radical quenching effect of the surface benzimidazole heterocycle. This prevents these free radicals from attacking the chromophores of dye molecules, thereby significantly improving the light fastness of the fabric. Furthermore, the 5-amino-2-mercaptobenzimidazole molecule itself carries an amino group that undergoes chemical cross-linking with the epoxy group of the epoxy-modified polyurethane in the final S3 baking step, greatly improving the physical fastness and long-term durability of the entire functional coating, such as wash resistance and abrasion resistance.

[0018] Preferably, the immersion rolling process in step S3 is a two-immersion two-roll process with a roll residue rate of 70-85%.

[0019] Preferably, the post-processing in step S3 is drying and baking, with the drying temperature at 90-110℃ and the baking temperature at 160-170℃ for 2-3 minutes.

[0020] The present invention also protects a fabric prepared by the finishing process described above.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The finishing process for improving the light fastness of fabric provided by the present invention involves modifying the surface of polyester fabric by introducing highly reactive thiol functional groups on it, and preparing modified titanium dioxide with 5-amino-2-mercaptobenzimidazole grafted on the surface. During the finishing process, through the bridging effect of epoxy-modified waterborne polyurethane, a highly stable three-dimensional network coating is formed between the fabric, polyurethane and titanium dioxide by chemical bonds under high temperature baking. The added modified titanium dioxide not only effectively inhibits the photodegradation of dyes caused by light and ultraviolet radiation, significantly improving the light fastness of the fabric, but also endows the fabric with excellent comprehensive physical fastness such as washability and abrasion resistance.

[0022] (2) The finishing process for improving the light fastness of fabrics provided by the present invention innovatively modifies polyester fabrics and adopts a two-step method of mild alkaline etching activation and silane coupling agent grafting. First, through the synergistic effect of mild sodium hydroxide solution and penetrating swelling modifier, a limited number of hydroxyl active sites are introduced only on the surface of polyester fibers, avoiding damage to fiber strength caused by deep reduction. Subsequently, γ-mercaptopropyltrimethoxysilane is used to undergo a dehydration condensation reaction with the hydroxyl groups on the surface of the fabric fibers, and highly active mercapto functional groups are firmly grafted onto the fibers in the form of covalent bonds, providing highly selective reaction targets for epoxy groups in the subsequent finishing solution, and constructing a bottom anchor point for a strong chemical bond between the finishing agent and the fabric fibers, fundamentally solving the problem of poor fastness caused by traditional resin finishing relying on physical coating.

[0023] (3) The finishing process for improving the light fastness of fabrics provided by this invention uses epoxy-modified waterborne polyurethane emulsion as a key multifunctional crosslinking center. The epoxy groups on its molecular chain are highly active. Under baking conditions, it can undergo efficient ring-opening addition reaction with the thiol groups grafted on the surface of polyester fabric fibers, and can also react with the amino groups loaded on the surface of modified titanium dioxide. This achieves dual locking of fiber substrate and functional filler. This covalent crosslinking network centered on polyurethane replaces the single film-forming mechanism of traditional finishing agents, so that the final composite coating has excellent cohesion and adhesion, ensuring low migration rate and high durability of functional additives during long-term use and washing. At the same time, the modified titanium dioxide is prepared by a two-step method. First, a vinylsilane coating is formed on the surface of titanium dioxide particles. Then, a free radical addition reaction initiated by azobisisobutyronitrile (AIBN) is used to graft 5-amino-2-mercaptobenzimidazole molecules, which have both amino and benzimidazole groups, onto the titanium dioxide. This not only improves the dispersibility of inorganic titanium dioxide in the waterborne polyurethane system through the silane layer, but more importantly, it introduces the photostable benzimidazole heterocyclic structure into the surface of titanium dioxide through chemical bonding. Through synergistic action, the modified titanium dioxide can quench the free radicals generated by the photocatalytic activity of titanium dioxide nearby and efficiently, thereby maximizing the synergistic anti-UV and photostable effects of the two, further ensuring the stability of fabric dyes and improving the light fastness of the fabric. Detailed Implementation

[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise specified, all chemical reagents and materials in this invention are purchased from the market or synthesized from raw materials purchased from the market.

[0026] The fatty alcohol polyoxyethylene ether is AEO-9; the titanium dioxide has a particle size of 50-80 nm; the epoxy-modified waterborne polyurethane emulsion was prepared according to the literature "Preparation and Membrane Properties of Epoxy-Modified Waterborne Polyurethane Emulsion, Lai Xiaojuan et al., Acta Polymerica Sinica, November 2009, Vol. 11", as follows: 550g of polycaprolactone diol was vacuum dehydrated at 110℃ for 2 hours and then added to a reaction vessel. The temperature was lowered to 30℃, followed by the addition of 310g of isophorone diisocyanate, 40g of dimethylolpropionic acid, and 400g of acetone. The mixture was thoroughly mixed, and the temperature was raised to 60℃. Then, 0.5g of dibutyltin dilaurate was added, and the reaction was carried out at 65℃ for 4 hours. Subsequently, 100g of epoxy resin E-44 was added, and the reaction was continued for 2 hours. After the reaction was completed, the system was cooled to room temperature, and 27g of triethylamine was added for neutralization. After stirring for 20 minutes and waiting for the pH of the system to stabilize, a mixture was obtained. Under high-speed stirring (1000 rpm), the mixture was slowly added to 2000 g of deionized water for reverse emulsification. After a uniform and stable emulsion was formed, a chain extender solution made of 26 g of ethylenediamine and 250 g of water was slowly added dropwise, and stirring was continued for 1 hour to complete the chain extension. Acetone was removed by vacuum distillation and the solid content was adjusted to finally obtain an epoxy-modified waterborne polyurethane emulsion with a solid content of 25%.

[0027] Example 1

[0028] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 0.8% sodium hydroxide solution with a material-to-solution ratio of 1:25. Then, a modifier is added at a mass ratio of 1.5% of the polyester fabric. The mixture is immersed at 55°C for 35 minutes. After treatment, the mixture is filtered and washed. Then, an ethanol-water solution (ethanol to water volume ratio of 95:5) is added with a material-to-solution ratio of 1:1. Next, 4.5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 65°C for 2.5 hours. After the reaction is complete, the mixture is removed, dried, and the modified fabric is obtained. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified titanium dioxide, 0.7 parts of 2-ethyl-4-methylimidazole, and 1.5 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 80%. The padded fabric is dried at 100°C to a moisture content of 10% and then baked at 165°C for 3 minutes.

[0029] The modifier in step S1 is prepared as follows: 25 parts by weight of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 20 parts of benzyl alcohol, 15 parts of sodium polyacrylate, and 2.5 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 50°C for 40 minutes to obtain the modifier.

[0030] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by 9g of vinyltriethoxysilane. The mixture was reacted at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by 10g of 5-amino-2-mercaptobenzimidazole and 0.15g of azobisisobutyronitrile. The mixture was reacted at 75℃ for 3.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0031] Example 2

[0032] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 0.5% sodium hydroxide solution with a material-to-solution ratio of 1:20. Then, a modifier is added at a mass ratio of 1% of the polyester fabric. The mixture is immersed at 50°C for 40 minutes. After treatment, it is filtered and washed. Then, it is added to an ethanol-water solution (ethanol to water volume ratio of 90:10) with a material-to-solution ratio of 1:10. Next, 4% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 60°C for 3 hours. After the reaction is completed, it is taken out and dried to obtain the modified fabric. S2. Preparation of finishing solution: By weight, add 50 parts of epoxy-modified waterborne polyurethane emulsion, 5 parts of modified titanium dioxide, 0.5 parts of 2-ethyl-4-methylimidazole, and 1 part of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly to obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 70%. The padded fabric is dried at 90°C to a moisture content of 15% and then baked at 160°C for 3 minutes.

[0033] The preparation method of the modifier in step S1 is as follows: by weight, 20 parts of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 15 parts of benzyl alcohol, 10 parts of sodium polyacrylate and 2 parts of disodium ethylenediaminetetraacetate, and stirred at 40°C for 50 min to obtain the modifier.

[0034] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 4:1), followed by 7g of vinyltriethoxysilane. The mixture was reacted at 50℃ for 6h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by 8g of 5-amino-2-mercaptobenzimidazole and 0.1g of azobisisobutyronitrile. The mixture was reacted at 70℃ for 4h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0035] Example 3

[0036] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 1% sodium hydroxide solution with a material-to-solution ratio of 1:30. Then, a modifier is added at a mass of 2% of the polyester fabric. The mixture is immersed at 60°C for 30 minutes. After treatment, it is filtered and washed. Then, it is added to an ethanol-water solution (ethanol to water volume ratio of 95:5) with a material-to-solution ratio of 1:12. Next, 5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 70°C for 2 hours. After the reaction is completed, it is taken out and dried to obtain the modified fabric. S2. Preparation of finishing solution: By weight, add 60 parts of epoxy-modified waterborne polyurethane emulsion, 8 parts of modified titanium dioxide, 0.8 parts of 2-ethyl-4-methylimidazole, and 2 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 85%. The padded fabric is dried at 110°C to a moisture content of 10% and then baked at 170°C for 2 minutes.

[0037] The modifier in step S1 is prepared as follows: 30 parts by weight of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 25 parts of benzyl alcohol, 20 parts of sodium polyacrylate, and 3 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 60°C for 30 minutes to obtain the modifier.

[0038] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by the addition of 10g of vinyltriethoxysilane. The mixture was reacted at 60℃ for 4h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by the addition of 11g of 5-amino-2-mercaptobenzimidazole and 0.2g of azobisisobutyronitrile. The mixture was reacted at 80℃ for 3h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0039] Comparative Example 1

[0040] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 0.8% sodium hydroxide solution with a material-to-solution ratio of 1:25. Then, a modifier is added at a mass ratio of 1.5% of the polyester fabric. The mixture is immersed at 55°C for 35 minutes. After treatment, the mixture is filtered and washed. Then, an ethanol-water solution (ethanol to water volume ratio of 95:5) is added with a material-to-solution ratio of 1:1. Next, 4.5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 65°C for 2.5 hours. After the reaction is complete, the mixture is removed, dried, and the modified fabric is obtained. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified titanium dioxide, 0.7 parts of 2-ethyl-4-methylimidazole, and 1.5 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 80%. The padded fabric is dried at 100°C to a moisture content of 10% and then baked at 165°C for 3 minutes.

[0041] The modifier in step S1 is prepared as follows: 25 parts by weight of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 20 parts of benzyl alcohol, 15 parts of sodium polyacrylate, and 2.5 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 50°C for 40 minutes to obtain the modifier.

[0042] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol aqueous solution (ethanol to water volume ratio of 5:1), followed by the addition of 9g of vinyltriethoxysilane. The mixture was reacted at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0043] Compared with Example 1, the modified titanium dioxide in this comparative example did not introduce 5-amino-2-mercaptobenzimidazole, that is, ethylene-modified titanium dioxide was used to replace the modified titanium dioxide.

[0044] Comparative Example 2

[0045] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 0.8% sodium hydroxide solution with a material-to-solution ratio of 1:25. Then, a modifier is added at a mass ratio of 1.5% of the polyester fabric. The mixture is immersed at 55°C for 35 minutes. After treatment, the mixture is filtered and washed. Then, an ethanol-water solution (ethanol to water volume ratio of 95:5) is added with a material-to-solution ratio of 1:1. Next, 4.5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 65°C for 2.5 hours. After the reaction is complete, the mixture is removed, dried, and the modified fabric is obtained. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified titanium dioxide, 0.7 parts of 2-ethyl-4-methylimidazole, and 1.5 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 80%. The padded fabric is dried at 100°C to a moisture content of 10% and then baked at 165°C for 3 minutes.

[0046] The modifier in step S1 is prepared as follows: by weight, 20 parts benzyl alcohol, 15 parts sodium polyacrylate, and 2.5 parts disodium ethylenediaminetetraacetate are added to 100 parts ethylene glycol and stirred at 50°C for 40 minutes to obtain the modifier.

[0047] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by 9g of vinyltriethoxysilane. The mixture was reacted at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by 10g of 5-amino-2-mercaptobenzimidazole and 0.15g of azobisisobutyronitrile. The mixture was reacted at 75℃ for 3.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0048] Compared to Example 1, the modifier in this comparative example did not include tetrabutylammonium bromide.

[0049] Comparative Example 3

[0050] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric is added to a 0.8% sodium hydroxide solution with a material-to-solution ratio of 1:25. Then, a modifier is added at a mass ratio of 1.5% of the polyester fabric. The mixture is immersed at 55°C for 35 minutes. After treatment, the mixture is filtered and washed. Then, an ethanol-water solution (ethanol to water volume ratio of 95:5) is added with a material-to-solution ratio of 1:1. Next, 4.5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane is added. The mixture is stirred and reacted at 65°C for 2.5 hours. After the reaction is complete, the mixture is removed, dried, and the modified fabric is obtained. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified titanium dioxide, 0.7 parts of 2-ethyl-4-methylimidazole, and 1.5 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 80%. The padded fabric is dried at 100°C to a moisture content of 10% and then baked at 165°C for 3 minutes.

[0051] The modifier in step S1 is prepared as follows: 25 parts by weight of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 15 parts of sodium polyacrylate and 2.5 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 50°C for 40 minutes to obtain the modifier.

[0052] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by 9g of vinyltriethoxysilane. The mixture was reacted at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by 10g of 5-amino-2-mercaptobenzimidazole and 0.15g of azobisisobutyronitrile. The mixture was reacted at 75℃ for 3.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0053] Compared to Example 1, benzyl alcohol was not added as a modifier in this comparative example.

[0054] Comparative Example 4

[0055] A finishing process for improving the light fastness of fabrics includes the following steps: S1. Fabric Modification: The dyed polyester fabric was added to a 0.8% sodium hydroxide solution with a polyester fabric to sodium hydroxide solution ratio of 1:25. The solution was immersed at 55°C for 35 minutes. After treatment, the fabric was filtered and washed. Then, the fabric was added to an ethanol aqueous solution (ethanol to water volume ratio of 95:5) with a polyester fabric to ethanol aqueous solution ratio of 1:1. Next, 4.5% of the polyester fabric mass of γ-mercaptopropyltrimethoxysilane was added. The mixture was stirred and reacted at 65°C for 2.5 hours. After the reaction was completed, the fabric was removed and dried to obtain the modified fabric. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified titanium dioxide, 0.7 parts of 2-ethyl-4-methylimidazole, and 1.5 parts of fatty alcohol polyoxyethylene ether to 200 parts of deionized water, stir evenly, and obtain the finishing solution. S3. Fabric finishing: The pretreated fabric is dipped and padded in the finishing solution. The padding process is two dips and two paddeds with a padded rate of 80%. The padded fabric is dried at 100°C to a moisture content of 10% and then baked at 165°C for 3 minutes.

[0056] The modifier in step S1 is prepared as follows: 25 parts by weight of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 20 parts of benzyl alcohol, 15 parts of sodium polyacrylate, and 2.5 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 50°C for 40 minutes to obtain the modifier.

[0057] The preparation method of the modified titanium dioxide in step S2 is as follows: 100g of titanium dioxide was added to 1L of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by 9g of vinyltriethoxysilane. The mixture was reacted at 55℃ for 5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, 100g of ethylene-modified titanium dioxide was added to 1L of DMF, followed by 10g of 5-amino-2-mercaptobenzimidazole and 0.15g of azobisisobutyronitrile. The mixture was reacted at 75℃ for 3.5h. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

[0058] Compared with Example 1, no modifier was added in this comparative example when modifying the fabric (i.e., step S1).

[0059] The fabrics prepared in Examples 1-3 and Comparative Examples 1-4 were subjected to performance tests. The light fastness was tested according to GB / T 8427-2019 "Textiles - Tests for Color Fastness - Color Fastness to Artificial Light: Xenon Arc". Each group of finished fabrics, along with one group of target blue wool standard samples (grades 1-8), were placed in a xenon arc lamp aging test chamber and exposed to sunlight according to Method 3, with a light intensity of 1.1 W / cm². 2The wavelength was 420nm, the blackboard temperature was 47℃, the chamber temperature was 39℃, and the relative humidity was 40%. The color change of the sample was compared with that of a blue wool standard sample, and the color was rated in a standard light source box to characterize the lightfastness of the dyed fabric. The colorfastness to washing was tested according to GB / T 3921-2008 "Textiles - Tests for Colorfastness - Washing Fastness". A 100mm×40mm sample was sewn together with a multi-fiber lining fabric of the same size (usually containing six fibers: acetate, cotton, nylon, polyester, acrylic, and wool) face to face to form a composite sample. The composite sample was then placed in a solution of specified soap (standard soap flake concentration 5g·L⁻¹). -1 In the test steel cup, the bath ratio is 50:1. Select test condition C(3), that is, wash with water at 60℃ for 45 minutes. After washing, rinse thoroughly with running cold water, gently squeeze out the water and spread out. Dry the sample. After the sample is completely dry, use GB / T 250-2008 "Gray Sample Card for Assessing Color Change" to assess the color change grade of the sample. There are 5 grades in total, with grade 5 being the best and grade 1 being the worst. The color fastness to rubbing is tested according to GB / T 3920-2008 "Color Fastness Tests for Textiles - Color Fastness to Rubbing". Cut samples with a size of not less than 140mm×50mm along the warp direction from the sample to be tested. Fix the sample on the base plate of the color fastness tester and perform dry rubbing test. Fix a 50mm×50mm standard rubbing cloth on the rubbing head and apply a vertical pressure of 9N. Rub the sample back and forth 10 times (stroke 100mm, frequency 1 time / second). After the test, use GB / T GB / T 251-2008 "Grey Sample Card for Stain Assessment" is used to assess the staining grade of rubbing white cloth. There are five grades, with grade 5 being the best and grade 1 the worst. Tear strength is tested according to GB / T 3917.1-2009 "Textiles - Tear Properties of Fabrics - Part 1: Determination of Tear Strength by Impact Pendulum Method". The sample is cut along the warp direction from the fabric to be tested. The standard sample size is 100mm × 63mm, ensuring that the long side (100mm) of the sample is strictly parallel to the warp direction of the fabric. The cut sample is fixed on the clamp of the impact pendulum tear tester. At this point, the weft yarn will be torn. The instrument makes an initial 20mm incision in the center of the sample, leaving a remaining tear length of 43mm. The hammer is released, and the instrument automatically records the work consumed in tearing this length of fabric and converts it into an average tearing force. The test results are shown in Table 1 below.

[0060] Table 1. Performance test results of fabrics in each embodiment and comparative example.

[0061] As can be seen from the table above, the finishing process for improving the light fastness of fabrics provided by this invention can significantly improve the light fastness of fabrics, while also improving the color fastness to washing, rubbing, and tear strength, and has good application prospects.

[0062] The above description is a further detailed explanation of the present invention in conjunction with specific implementation examples. It should not be considered that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all such deductions or substitutions should be considered to fall within the protection scope of the present invention.

[0063] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A finishing process for improving the light fastness of fabrics, characterized in that, Includes the following steps: S1. Add the dyed polyester fabric to a sodium hydroxide solution, then add the modifier and impregnate it. After the treatment is completed, filter and wash it. Then add it to an ethanol aqueous solution, add γ-mercaptopropyltrimethoxysilane, stir and react. After the reaction is completed, take it out and dry it to obtain the modified fabric. S2. Add epoxy-modified waterborne polyurethane emulsion, modified titanium dioxide, 2-ethyl-4-methylimidazolium, and fatty alcohol polyoxyethylene ether to deionized water and stir evenly to obtain a finishing solution. S3. The pretreated fabric is immersed in the finishing solution for padding, and the padded fabric is then subjected to post-treatment.

2. The finishing process according to claim 1, characterized in that, The modifier in step S1 is prepared as follows: by weight, 20-30 parts of tetrabutylammonium bromide are added to 100 parts of ethylene glycol, followed by 15-25 parts of benzyl alcohol, 10-20 parts of sodium polyacrylate, and 2-3 parts of disodium ethylenediaminetetraacetate. The mixture is stirred at 40-60℃ for 30-50 minutes to obtain the modifier.

3. The finishing process according to claim 1, characterized in that, In step S1, the mass concentration of the sodium hydroxide solution is 0.5-1%, the ratio of the polyester fabric to the sodium hydroxide solution is 1:20-30, the amount of the modifier added is 1-2% of the mass of the polyester fabric, and the immersion treatment temperature is 50-60℃ for 30-40 minutes.

4. The finishing process according to claim 1, characterized in that, In step S1, the volume ratio of ethanol to water in the ethanol-water solution is 90-95:5-10, the amount of γ-mercaptopropyltrimethoxysilane added is 4-5% of the mass of the polyester fabric, the temperature of the stirring reaction is 60-70℃, and the time is 2-3h.

5. The finishing process according to claim 1, characterized in that, In step S2, the amounts of each raw material in the finishing solution by weight are as follows: 50-60 parts of epoxy-modified waterborne polyurethane emulsion, 5-8 parts of modified titanium dioxide, 0.5-0.8 parts of 2-ethyl-4-methylimidazole, 1-2 parts of fatty alcohol polyoxyethylene ether, and 200 parts of deionized water.

6. The finishing process according to claim 1, characterized in that, The preparation method of the modified titanium dioxide in step S2 is as follows: Titanium dioxide was added to an aqueous ethanol solution, followed by the addition of vinyltriethoxysilane, and the mixture was heated to react. After the reaction was completed, the mixture was filtered, washed, and dried to obtain ethylene-modified titanium dioxide. Subsequently, the ethylene-modified titanium dioxide was added to DMF, followed by the addition of 5-amino-2-mercaptobenzimidazole and azobisisobutyronitrile, and the mixture was subjected to a constant-temperature reaction. After the reaction was completed, the mixture was filtered, washed, and dried to obtain modified titanium dioxide.

7. The finishing process according to claim 6, characterized in that, The volume ratio of ethanol to water in the ethanol-water solution is 4-5:1; the mass ratio of titanium dioxide to vinyltriethoxysilane is 100:7-10; the heating reaction temperature is 50-60℃ and the time is 4-6h; the mass ratio of ethyleneized titanium dioxide, 5-amino-2-mercaptobenzimidazole, and azobisisobutyronitrile is 100:8-11:0.1-0.2; the isothermal reaction temperature is 70-80℃ and the time is 3-4h.

8. The finishing process according to claim 1, characterized in that, The immersion rolling process described in step S3 is a two-dip, two-roll process with a roll residue of 70-85%.

9. The finishing process according to claim 1, characterized in that, The post-processing in step S3 is drying and baking. The drying temperature is 90-110℃, and the baking temperature is 160-170℃ for 2-3 minutes.

10. A fabric prepared by the finishing process according to any one of claims 1-9.

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