After-finishing process for improving stiffness of fabric

Abstract

The invention discloses an after-finishing process for improving fabric stiffness, which comprises the following steps: S1, adding a polyester fabric into a sodium hydroxide solution, and carrying out dipping treatment to obtain a pretreated fabric; s2, adding epoxy modified waterborne polyurethane emulsion, modified silicon dioxide, 2-ethyl-4-methylimidazole and fatty alcohol-polyoxyethylene ether into deionized water, and uniformly stirring 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. Compared with the prior art, the polyester fabric is pretreated by adopting an alkali liquor dipping process, a microscopic coarse structure is formed on the surface of the fiber, modified silicon dioxide introduced into finishing liquor is used as a functional filler, and the process greatly limits relative slippage of the fiber on the surface of the fiber and in gaps of the fiber by adopting a high-strength and high-modulus three-dimensional interpenetrating network structure; therefore, the fabric is endowed with excellent, lasting and washable stiff effect and form stability.

Description

Technical Field

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

[0002] The feel and style of a fabric are among the key attributes that determine its end use and added value. Among the many styles, a stiff, smooth appearance with good shape retention is widely in demand in clothing (such as shirts and coats), home textiles (such as curtains and tablecloths), and industrial textiles. Many fabrics in their natural state, especially synthetic fiber fabrics such as polyester, are relatively soft and easily deformed, making them difficult to meet the requirements of these specific applications. Therefore, improving the stiffness and dimensional stability of fabrics through finishing processes is a common and important technique in textile processing.

[0003] Currently, traditional methods for achieving fabric stiffness finishing mainly fall into the following categories: The first category utilizes the principle of polymer film formation. This method typically applies polymer emulsions such as polyvinyl acetate (PVA), polyacrylate (PA), and polyurethane (PU) to the fabric surface through padding. After drying, the polymer film fills the gaps between fibers and bonds them together, thereby restricting the relative movement of the fibers and achieving the goal of improving fabric stiffness. However, this method has some inherent drawbacks: First, the bonding between the finishing agent and the fibers (especially chemically stable polyester fibers) mainly relies on physical actions such as van der Waals forces, resulting in poor bonding strength and a short-lasting finishing effect; the stiffness effect will significantly decrease after multiple washes. Second, to achieve the ideal stiffness, a high amount of finishing agent is often required, which can lead to an excessively stiff and brittle fabric feel, reduced breathability, and even affect the original luster and color of the fabric.

[0004] The second type involves adding inorganic rigid particles, such as ordinary silica, calcium carbonate, and kaolin, to polymer emulsions to form organic / inorganic composite finishing. The introduction of inorganic particles can, to some extent, increase the modulus of the finished film and enhance its stiffness. However, unmodified inorganic particles have poor compatibility with the organic polymer matrix, easily agglomerating and settling in the finishing solution, leading to uneven dyeing and defects such as white spots and powder marks on the fabric surface. Simultaneously, due to weak interfacial bonding, these inorganic particles are easily detached from the polymer film under external force or washing, resulting in poor durability of the stiffness effect.

[0005] The third category involves self-crosslinking or external crosslinking finishing agents. For example, resin finishing agents containing functional groups such as N-hydroxymethylacrylamide can undergo crosslinking reactions under high temperatures and catalysis to form a network structure, thus giving the fabric a better stiffness. However, these formaldehyde-based resin finishing agents release free formaldehyde during processing and use, posing a potential threat to human health and the ecological environment, and their application is subject to increasingly stringent regulations. Developing formaldehyde-free or low-formaldehyde environmentally friendly crosslinking finishing technologies has become an inevitable trend in the industry.

[0006] Therefore, developing a finishing technology that can impart excellent and washable stiffness to fabrics while maintaining a good hand feel, and whose process is environmentally friendly and efficient, has significant practical application value and market prospects. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a finishing process to improve the stiffness of fabrics.

[0008] To achieve the above objectives, the present invention provides the following technical solution: A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: The polyester fabric is immersed in sodium hydroxide solution for immersion treatment. After treatment, it is filtered and washed to obtain the pretreated fabric. S2. Preparation of finishing solution: Add epoxy-modified waterborne polyurethane emulsion, modified silica, 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.

[0009] Preferably, the mass concentration of the sodium hydroxide solution in step S1 is 1.5-2%, the ratio of the polyester fabric to the sodium hydroxide solution is 1:20-30, the immersion treatment temperature is 70-80℃, and the time is 20-30 min.

[0010] In this invention, a sodium hydroxide solution of a certain concentration is used to perform surface hydrolysis on polyester at a certain temperature, ensuring that the hydrolysis only occurs on the fiber surface. This achieves micro-etching without excessively damaging the polyester fiber matrix, thus avoiding a significant decrease in fabric strength. This pretreatment etches microscopic pits and grooves into the smooth fiber surface. These rough structures greatly increase the specific surface area of ​​the fiber, providing a physical basis for the mechanical bonding between the finishing agent and the fiber, and improving the adhesion between the finishing agent and the fiber.

[0011] 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 silica, 0.5-0.8 parts of 2-ethyl-4-methylimidazole, 1-2 parts of fatty alcohol polyoxyethylene ether, and 200 parts of deionized water.

[0012] 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 fiber interlacing points. This film itself has a certain strength and modulus, and by filling the gaps between fibers and bonding the fibers, it provides a basic stiffness effect and skeletal support. Furthermore, the epoxy groups it contains are active groups that will subsequently react chemically with modified silica. Modified silica, as a core functional filler and rigidity reinforcement core, possesses both the core rigidity of inorganic materials and the surface activity and compatibility of organic materials. The amino groups it contains react with the epoxy groups on the polyurethane molecular chains to form three-dimensional network cross-linking points, thereby greatly restricting the movement of polymer chain segments and enhancing the stiffness of the fabric. 2-Ethyl-4-methylimidazole acts as a catalyst to ensure that the cross-linking reaction between amino and epoxy groups can proceed rapidly, efficiently, and as completely as possible within a set time. Fatty alcohol polyoxyethylene ether, as a nonionic surfactant, reduces the surface tension of water, enabling the finishing liquid to quickly and evenly wet the fabric surface and penetrate into the fiber interior.

[0013] Preferably, the modified silica in step S2 is prepared by the following method: (a) Add silicon dioxide to an aqueous ethanol solution, then add γ-aminopropyltriethoxysilane, heat the reaction, filter, wash and dry after the reaction is complete to obtain aminated silicon dioxide; (b) Aminated silica was added to acetone, followed by cyanuric chloride. The mixture was stirred and reacted. Triethylamine was added during the reaction. The pH of the system was kept at 7-8. After the reaction was completed for the preset time, the mixture was filtered, washed, and dried to obtain organosilica. (c) Add organo-modified silica to DMF, then add p-phenylenediamine and potassium carbonate, and carry out a constant temperature reaction. After the reaction is completed, filter, wash and dry to obtain modified silica.

[0014] Preferably, in step (a), the volume ratio of ethanol to water is 4-5:1, the mass ratio of silicon dioxide to γ-aminopropyltriethoxysilane is 100:5-8, the heating reaction temperature is 70-75°C, and the time is 4-6 hours.

[0015] In this invention, silicon dioxide is reacted with γ-aminopropyltriethoxysilane to introduce an active amino group.

[0016] Preferably, in step (b), the mass ratio of aminated silica to cyanuric chloride is 100:4.2-6.7, the temperature of the stirring reaction is 0-5℃, and the time is 2-3h.

[0017] Preferably, in step (c), the mass ratio of organosilica, p-phenylenediamine, and potassium carbonate is 100:6-10:15-25, the temperature of the isothermal reaction is 70-80℃, and the time is 8-10h.

[0018] In this invention, aminated silica is reacted with cyanuric chloride. By controlling the reaction temperature, one chlorine atom of the cyanuric chloride reacts with the amino group, thereby introducing the cyanuric chloride molecule onto the silica. Then, the organo-silica is reacted with excess p-phenylenediamine. At a higher temperature, the remaining two less reactive chlorine atoms on the cyanuric chloride ring can react with the amino group of p-phenylenediamine, thus introducing a p-aminophenyl structure. The unreacted amino group at the other end of the p-phenylenediamine serves as the active site for subsequent reactions, and is involved in the baking stage and epoxy modification. The waterborne polyurethane matrix undergoes efficient chemical cross-linking, forming a robust and dense three-dimensional interpenetrating network, thereby improving the stiffness of the fabric. By introducing a series of organic segments such as aminopropyl, triazine ring, and p-phenylenediamine onto the silica surface, these organic segments act as a buffer layer, improving the compatibility between the rigid inorganic core and the flexible polyurethane matrix, reducing stress concentration, and thus endowing the composite film with excellent toughness. Ultimately, the finished fabric achieves excellent stiffness while avoiding excessive stiffness and brittleness.

[0019] Preferably, the immersion rolling process in step S3 is a two-immersion two-roll process with a roll residue rate of 70-85%.

[0020] 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.

[0021] The present invention also protects a fabric prepared by the finishing process described above.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) The finishing process for improving the stiffness of fabric provided by the present invention pre-treats polyester fabric by using an alkaline impregnation process to form a micro-rough structure on the fiber surface, which enhances the physical adhesion of subsequent finishing agents. More importantly, a modified silica with a large number of active amino groups prepared by a specific method is introduced into the finishing solution as a functional filler, which is compounded with epoxy-modified waterborne polyurethane and imidazole catalyst. Under high temperature baking conditions, the epoxy-modified waterborne polyurethane emulsion is used as the base resin. After drying, it will form a continuous and transparent film between the fabric surface and the fiber interlacing points. At the same time, the epoxy groups of the epoxy-modified waterborne polyurethane emulsion undergo an efficient ring-opening addition reaction with the amino groups on the surface of modified silica. This process forms a high-strength, high-modulus three-dimensional interpenetrating network structure on the fiber surface and between fibers, which is formed by cross-linking polyurethane flexible segments and silica rigid particles through chemical bonds. This network structure firmly welds the fiber nodes, greatly restricting the relative slippage of fibers, thereby giving the fabric excellent, durable and washable stiffness and morphological stability.

[0023] (2) The finishing process for improving fabric stiffness provided by this invention involves adding modified silica to the finishing solution. First, γ-aminopropyltriethoxysilane introduces active amino groups onto the silica surface. Then, cyanuric chloride is used as a multifunctional bridging agent, and its active chlorine atoms react with the amino groups on the silica surface at low temperature, grafting the triazine ring structure onto the silica surface. Finally, the remaining two active chlorine atoms on the triazine ring react with excess p-phenylenediamine to introduce a p-aminophenyl structure, thereby constructing a rigid planar structure with benzene rings and triazine rings on the silica surface, which is significantly improved. This significantly improves the modulus of modified silica particles. At the same time, the unreacted amino group at the other end of the p-phenylenediamine not only greatly increases the number of reactive sites, ensuring efficient cross-linking with the epoxy matrix, but also the linear p-phenylenediamine molecules extend from the triazine ring bifurcation point, increasing the thickness of the organic shell and the length of the chain segments, improving the compatibility between inorganic particles and the polymer matrix, and also acting as a flexible buffer layer, reducing stress concentration. This results in a composite film that is both highly rigid and has a certain degree of toughness, avoiding excessive stiffness and brittleness after finishing.

[0024] (3) The finishing process for improving fabric stiffness provided by the present invention introduces 2-ethyl-4-methylimidazolium as a catalyst for the epoxy-amino crosslinking reaction in the finishing solution. The imidazolium catalyst has typical latent characteristics, that is, its activity is low at room temperature (during the preparation and storage of the finishing solution), which can ensure that the finishing working solution has good storage stability and usage window. Under high temperature baking conditions, its catalytic activity is rapidly activated, and through the dual mechanisms of nucleophilic catalysis and base catalysis, it greatly accelerates the ring-opening addition reaction rate of epoxy groups. This allows the entire crosslinking and curing process to be completed efficiently in a short time of 2-3 minutes, which fully meets the process requirements of high-speed continuous production in the modern printing and dyeing industry. While ensuring the finishing effect, it significantly improves production efficiency and reduces unit energy consumption. Detailed Implementation

[0025] 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.

[0026] 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.

[0027] The fatty alcohol polyoxyethylene ether is AEO-9; the silica 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%.

[0028] Example 1

[0029] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a sodium hydroxide solution with a mass concentration of 1.8% and the ratio of polyester fabric to sodium hydroxide solution is 1:25. Immerse the fabric at 75℃ for 25 minutes. After treatment, filter and wash to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified silica, 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 until the moisture content is 10%, and then baked at 165°C for 3 minutes.

[0030] The method for preparing the modified silica in step S2 is as follows: (a) 100g of silica was added to 800mL of ethanol aqueous solution (ethanol to water volume ratio of 5:1), followed by 7g of γ-aminopropyltriethoxysilane. The reaction was carried out at 75℃ for 5h. After the reaction was completed, the silica was filtered, washed and dried to obtain aminated silica. (b) Add 100g of aminated silica to 1L of acetone, then add 5g of cyanuric chloride, stir at 3°C, add triethylamine during the reaction, keep the pH of the system at 7-8, after 2.5 reaction, filter, wash and dry to obtain organosilica; (c) Add 100g of organosilica to 1L of DMF, then add 8g of p-phenylenediamine and 20g of potassium carbonate, and react at 75°C for 9h. After the reaction is complete, filter, wash and dry to obtain modified silica.

[0031] Example 2

[0032] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a 1.5% sodium hydroxide solution with a polyester fabric to sodium hydroxide solution ratio of 1:20, immerse at 70°C for 30 minutes, filter and wash after treatment to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 50 parts of epoxy-modified waterborne polyurethane emulsion, 5 parts of modified silica, 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 until the moisture content is 15%, and then baked at 160°C for 3 minutes.

[0033] The method for preparing the modified silica in step S2 is as follows: (a) 100g of silica was added to 800mL of ethanol aqueous solution (ethanol to water volume ratio of 4:1), followed by 5g of γ-aminopropyltriethoxysilane. The reaction was carried out at 70℃ for 6h. After the reaction was completed, the silica was filtered, washed and dried to obtain aminated silica. (b) Add 100g of aminated silica to 1L of acetone, then add 4.2g of cyanuric chloride, stir the reaction at 0°C, add triethylamine during the reaction, keep the pH of the system at 7-8, and after reacting for 3 hours, filter, wash and dry to obtain organosilica. (c) Add 100g of organosilica to 1L of DMF, then add 6g of p-phenylenediamine and 15g of potassium carbonate, and react at 70°C for 10h. After the reaction is complete, filter, wash and dry to obtain modified silica.

[0034] Example 3

[0035] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a 2% sodium hydroxide solution with a polyester fabric to sodium hydroxide solution ratio of 1:30, immerse at 80℃ for 20 minutes, filter and wash after treatment to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 60 parts of epoxy-modified waterborne polyurethane emulsion, 8 parts of modified silica, 0.8 parts of 2-ethyl-4-methylimidazole, and 2 parts 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 85%. The padded fabric is dried at 110°C until the moisture content is 10%, and then baked at 170°C for 2 minutes.

[0036] The method for preparing the modified silica in step S2 is as follows: (a) 100g of silica was added to 800mL of ethanol aqueous solution (ethanol to water volume ratio of 5:1), followed by 8g of γ-aminopropyltriethoxysilane. The reaction was carried out at 75℃ for 4h. After the reaction was completed, the silica was filtered, washed and dried to obtain aminated silica. (b) Add 100g of aminated silica to 1L of acetone, then add 6.7g of cyanuric chloride, stir the reaction at 5°C, add triethylamine during the reaction, keep the pH of the system at 7-8, and after reacting for 2 hours, filter, wash and dry to obtain organosilica. (c) Add 100g of organosilica to 1L of DMF, then add 10g of p-phenylenediamine and 25g of potassium carbonate, and react at 80℃ for 8h. After the reaction is complete, filter, wash and dry to obtain modified silica.

[0037] Comparative Example 1

[0038] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a sodium hydroxide solution with a mass concentration of 1.8% and the ratio of polyester fabric to sodium hydroxide solution is 1:25. Immerse the fabric at 75℃ for 25 minutes. After treatment, filter and wash to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified silica, 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 until the moisture content is 10%, and then baked at 165°C for 3 minutes.

[0039] The method for preparing the modified silica in step S2 is as follows: (a) 100g of silica was added to 800mL of ethanol aqueous solution (ethanol to water volume ratio of 5:1), followed by 7g of γ-aminopropyltriethoxysilane. The reaction was carried out at 75℃ for 5h. After the reaction was completed, the silica was filtered, washed and dried to obtain aminated silica. (b) Add 100g of aminated silica to 1L of acetone, then add 5g of cyanuric chloride, stir at 3°C, add triethylamine during the reaction, keep the pH of the system at 7-8, after 2.5 days of reaction, filter, wash and dry to obtain modified silica.

[0040] Compared with Example 1, the modified silica in this comparative example does not introduce p-phenylenediamine, i.e., step (c) is omitted.

[0041] Comparative Example 2

[0042] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a sodium hydroxide solution with a mass concentration of 1.8% and the ratio of polyester fabric to sodium hydroxide solution is 1:25. Immerse the fabric at 75℃ for 25 minutes. After treatment, filter and wash to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified silica, 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 until the moisture content is 10%, and then baked at 165°C for 3 minutes.

[0043] The method for preparing the modified silica in step S2 is as follows: (a) 100g of silica was added to 800mL of ethanol aqueous solution (ethanol to water volume ratio of 5:1), followed by 7g of γ-aminopropyltriethoxysilane. The reaction was carried out at 75℃ for 5h. After the reaction was completed, the silica was filtered, washed and dried to obtain aminated silica. (b) Add 100g of aminated silica to 1L of DMF, then add 14g of 25% glutaraldehyde aqueous solution, 8g of p-phenylenediamine and 0.4g of triethylamine, and react at 75°C for 9h. After the reaction is complete, filter, wash and dry to obtain modified silica.

[0044] Compared to Example 1, this comparative example of modified silica did not introduce cyanuric chloride, but instead used glutaraldehyde.

[0045] Comparative Example 3

[0046] A finishing process for improving the stiffness of fabrics includes the following steps: S1. Fabric pretreatment: Add polyester fabric to a sodium hydroxide solution with a mass concentration of 1.8% and the ratio of polyester fabric to sodium hydroxide solution is 1:25. Immerse the fabric at 75℃ for 25 minutes. After treatment, filter and wash to obtain pretreated fabric. S2. Preparation of finishing solution: By weight, add 55 parts of epoxy-modified waterborne polyurethane emulsion, 7 parts of modified silica, 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 until the moisture content is 10%, and then baked at 165°C for 3 minutes.

[0047] The method for preparing the modified silica in step S2 is as follows: 100g of silica was added to 800mL of ethanol-water solution (ethanol to water volume ratio of 5:1), followed by 5g of cyanuric chloride and 8g of p-phenylenediamine. After stirring evenly, the solvent was removed by rotary evaporation to obtain modified silica.

[0048] Compared with Example 1, the modified silica in this comparative example was obtained by physical blending silica with cyanuric chloride and p-phenylenediamine.

[0049] The fabrics prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. Stiffness was tested according to standard GB / T 18318.1-2009 "Determination of Bending Properties of Textiles - Part 1: Inclined Plane Method" by measuring the fabric's bending length. Bending length refers to the elongation of the sample as it extends from the platform, bends and droops due to its own weight, and contacts the inclined plane test line. Half of the elongation is the bending length of the sample, also known as the fabric's stiffness. Sample specifications: The stiffened polyester fabric was cut into rectangles of 20cm × 2.5cm and tested on an electronic stiffness meter. Fabric washability: The stiffness of the fabric after 50 washes was tested according to GB / T 8629-2017 "Textiles - Testing - Household Washing and Drying Procedures" by using 2g / L of soap powder. -1Wash the samples with water at 60±3℃ for 10 minutes, repeating this washing cycle 50 times per sample. After natural drying, test the stiffness. The wrinkle recovery angle is tested according to GB / T 3819-1997 "Textiles - Determination of Wrinkle Recovery Performance - Recovery Angle Method". The wrinkle recovery angle is measured vertically under the following conditions: 10N load, 5 minutes loading time, and 5 minutes of wrinkle recovery. Record the angle between the two ends of the material, i.e., the wrinkle recovery angle θ. This angle indicates the wrinkle recovery characteristics of the material; a larger recovery angle indicates better wrinkle resistance. Tear strength is measured according to GB / T... The test was conducted according to 3917.1-2009 "Textiles - Tear Properties of Fabrics - Part 1: Determination of Tear Strength by Impact Pendulum Method". A sample was cut along the warp direction from the fabric to be tested. The standard sample size was 100mm × 63mm, ensuring that the long side (100mm) of the sample was strictly parallel to the warp direction of the fabric. The cut sample was fixed on the clamp of the impact pendulum tear tester. At this point, the weft yarn would be torn. The instrument made an initial slit of 20mm in the center of the sample, leaving a remaining tear length of 43mm. The hammer was released, and the instrument automatically recorded the work consumed in tearing this length of fabric and converted it into an average tearing force. The test results are shown in Table 1 below.

[0050] Table 1. Performance test results of fabrics in each embodiment and comparative example.

[0051] As can be seen from Table 1 above, the finishing process for improving fabric stiffness provided by the present invention can significantly improve the stiffness of the fabric and at the same time improve the water resistance of the fabric, and has good application prospects.

[0052] 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.

[0053] 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 stiffness of fabrics, characterized in that, Includes the following steps: S1. Add the polyester fabric to the sodium hydroxide solution for immersion treatment. After the treatment is completed, filter and wash to obtain the pretreated fabric. S2. Add epoxy-modified waterborne polyurethane emulsion, modified silica, 2-ethyl-4-methylimidazolium, and fatty alcohol polyoxyethylene ether to deionized water and stir until homogeneous to obtain 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, In step S1, the mass concentration of the sodium hydroxide solution is 1.5-2%, the ratio of the polyester fabric to the sodium hydroxide solution is 1:20-30, the immersion treatment temperature is 70-80℃, and the time is 20-30 min.

3. 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 silica, 0.5-0.8 parts of 2-ethyl-4-methylimidazole, 1-2 parts of fatty alcohol polyoxyethylene ether, and 200 parts of deionized water.

4. The finishing process according to claim 1, characterized in that, The method for preparing the modified silica in step S2 is as follows: (a) Add silicon dioxide to an aqueous ethanol solution, then add γ-aminopropyltriethoxysilane, heat the reaction, filter, wash and dry after the reaction is complete to obtain aminated silicon dioxide; (b) Aminated silica was added to acetone, followed by cyanuric chloride. The mixture was stirred and reacted. Triethylamine was added during the reaction. The pH of the system was kept at 7-8. After the reaction was completed for the preset time, the mixture was filtered, washed, and dried to obtain organosilica. (c) Add organo-modified silica to DMF, then add p-phenylenediamine and potassium carbonate, and carry out a constant temperature reaction. After the reaction is completed, filter, wash and dry to obtain modified silica.

5. The finishing process according to claim 4, characterized in that, In step (a), the volume ratio of ethanol to water is 4-5:1, the mass ratio of silicon dioxide to γ-aminopropyltriethoxysilane is 100:5-8, the heating reaction temperature is 70-75℃, and the time is 4-6h.

6. The finishing process according to claim 4, characterized in that, In step (b), the mass ratio of aminated silica to cyanuric chloride is 100:4.2-6.7, the temperature of the stirring reaction is 0-5℃, and the time is 2-3h.

7. The finishing process according to claim 4, characterized in that, In step (c), the mass ratio of organic silica, p-phenylenediamine, and potassium carbonate is 100:6-10:15-25, and the isothermal reaction is carried out at a temperature of 70-80°C for 8-10 hours.

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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