A cross-linking type color fixing agent for improving the dyeing fastness of polyester-cotton blended fabric and a preparation method thereof

Abstract

The application discloses a cross-linking type color fixing agent for improving the dyeing fastness of polyester-cotton blended fabric and a preparation method thereof. The agent is a two-component system comprising a bio-based hyperbranched polymer and an organic metal complex catalyst. The polymer is formed by reacting one of a bio-based polycarboxylic acid and an anhydride with an epoxy compound to form a hyperbranched skeleton, and grafting a cationic quaternary ammonium salt side chain, with a residual hydroxyl value not less than 40 mg KOH / g and a branching degree of 0.5-0.65. The catalyst is a titanium ester-acetylacetone complex. When used, the catalyst component is added to the polymer component under stirring, and a working solution with a pH of 4.0-6.0 is obtained after aging. Through the dual effects of physical coating of the hyperbranched skeleton and chemical bonding of the cationic side chain, the fixing effect on polyester disperse dyes and cotton anionic dyes is synergistically improved, the wet rubbing and soaping fastness of polyester-cotton blended fabric is significantly improved under mild conditions, and the fabric hand is not affected.

Description

Technical Field

[0001] This invention relates to the field of textile printing and dyeing auxiliaries, specifically to a cross-linked color-fixing auxiliary for improving the color fastness of polyester-cotton blended fabrics and its preparation method, and more particularly to a two-component color-fixing system based on a bio-based hyperbranched polymer with grafted cationic quaternary ammonium salt side chains. Background Technology

[0002] Polyester-cotton blended fabrics are widely used in clothing and home textiles due to their combination of the strength and abrasion resistance of polyester with the moisture absorption and comfort of cotton. However, the dyeing process for polyester-cotton blended fabrics typically requires the separate use of disperse dyes and reactive dyes, as well as direct dyes and other anionic dyes, which makes color fixation particularly complex. After dyeing, especially for dark-colored varieties, problems such as failure to meet standards for wet rubbing fastness and soaping fastness often occur.

[0003] Currently, commercially available color-fixing agents can be mainly divided into the following categories: cationic color-fixing agents: these primarily improve the fastness of cotton dyes by forming ionic bonds with anionic dyes, but their effect on disperse dyes in polyester is limited; reactive color-fixing agents: these bind to fibers through covalent bonds, but often require high-temperature and strong alkaline conditions, which may damage the fabric; resin-based color-fixing agents: these tend to make the fabric feel stiff and may release harmful substances such as formaldehyde. A single color-fixing mechanism is insufficient to simultaneously meet the fixation requirements of two different types of dyes on both polyester and cotton fibers.

[0004] In recent years, hyperbranched polymers have shown potential in the field of functional finishing of textiles due to their unique spherical three-dimensional structure, numerous terminal functional groups, and low viscosity. However, their application in the color fixing of polyester-cotton blended fabrics, especially the development of auxiliary systems that combine high-efficiency color fixing performance, environmental friendliness, ease of use, and good hand feel, remains a pressing technical challenge in this field. Summary of the Invention

[0005] Purpose of the invention The primary objective of this invention is to provide a cross-linking color-fixing agent that is highly efficient, environmentally friendly, and can comprehensively improve the color fastness of polyester-cotton blended fabrics.

[0006] Another objective of this invention is to provide a method for preparing the above-mentioned color-fixing agent, particularly a method for synthesizing a bio-based hyperbranched polymer as a key component, so as to ensure the stability and reproducibility of product quality.

[0007] Technical solution To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a cross-linked color-fixing auxiliary for improving the color fastness of polyester-cotton blended fabrics. It is a two-component system comprising a bio-based hyperbranched polymer and an organometallic complex catalyst, wherein: Component A: An aqueous dispersion of the bio-based hyperbranched polymer; the polymer mass fraction in the aqueous dispersion is 15%-35%, and no visible stratification is observed after standing at 25°C for 24 hours; Component B: A stabilized organometallic complex catalyst, which is a stable complex formed by the complexation of tetraisopropyl titanate and acetylacetone in a molar ratio of 1:2 to 1:4, and a solution of tetraisopropyl titanate isopropanol with a mass fraction of 15%-25%. In this process, component B is slowly added dropwise to component A under stirring at 300-600 rpm. After mixing, the mixture is allowed to mature for 10-30 minutes to obtain a homogeneous finishing working solution with no visible particles and a turbidity of no more than 10 NTU measured at 660 nm at 25±2℃. The pH of the working solution is adjusted and stabilized at 4.0-6.0 by adding 0.1-0.3 mol / L acetate-sodium acetate buffer. The working solution should be used within 4 hours. The mass ratio of the polymer in component A to component B is between 100:2 and 100:8.

[0008] Furthermore, the bio-based hyperbranched polymer is prepared by a ring-opening addition reaction of a bio-based polycarboxylic acid and anhydride with an epoxy compound; the bio-based polycarboxylic acid is a tricarboxylic acid; and the epoxy compound is epichlorohydrin.

[0009] Furthermore, the bio-based hyperbranched polymer has grafted cationic quaternary ammonium salt side chains, with a residual hydroxyl value of not less than 40 mg KOH / g, a branching degree of 0.5-0.65, and a weight-average molecular weight of 8000-40000.

[0010] Furthermore, the degree of branching of the polymer was determined by proton nuclear magnetic resonance spectroscopy, specifically using one of the following solvents: deuterated water or a mixture of deuterated water and deuterated methanol in a 1:1 volume ratio. The branching degree was calculated using the formula: branching degree = (I branch / I total ) calculate, where I branch The integral area of ​​the hydrogen attributable to the branching sites of the polymer backbone in the chemical shift range of 2.6–3.2 ppm is the sum of the integral area of ​​the hydrogen attributable to the terminal quaternary ammonium salt methyl (-N+(CH3)3) hydrogen at the chemical shift of 3.25 ppm. The integral boundaries of the two peak areas were accurately separated by Lorentz peak shape fitting using MestReNova. total The integral area is the sum of all peak intensities not less than 2% of the intensity of the strongest polymer characteristic peak in the range of chemical shift 1.0-5.0 ppm, which can be clearly attributed to the polymer backbone and side chain hydrogens. The integral of the residual water peak at chemical shift 4.79 ppm needs to be subtracted by measuring the spectrum of the blank solvent under the same conditions.

[0011] Further, the grafting conversion rate of the quaternary ammonium salt side chain of the grafted cation is determined by nuclear magnetic resonance hydrogen spectroscopy. Specifically, using one of the following solvents as a solvent, deuterated water or a mixed solvent of deuterated water and deuterated methanol in a volume ratio of 1:1, the integral area ratio of the single peak of the grafted polymer at a chemical shift of 3.25 ppm to that at a chemical shift of 3.85 ± 0.05 ppm, which is attributed to the hydrogen of the specific methylene structure (-O-CH2-CH(OH)-CH2-) in the main chain, is compared. The residual hydroxyl value is calculated based on the grafting conversion rate, the amount of quaternizing reagent added, and the formula: residual hydroxyl value = intermediate hydroxyl value - (moles of quaternizing reagent added × grafting conversion rate × 56100) / net mass of polymer after deducting inorganic salts, wherein the net mass of polymer is the mass of the solid product obtained after freeze-drying in step S6.

[0012] Furthermore, the water content of the polymer product is not higher than 1.0% w / w, and the total inorganic salt content is lower than 0.2% w / w. The total inorganic salt content is determined by ion chromatography. The ion chromatography conditions are as follows: using an anion exchange column IonPac AS11-HC (4×250 mm) and a cation exchange column IonPac CS12A (4×250 mm), with KOH solution and 20 mM methanesulfonic acid solution as eluents, respectively, using a suppressed conductivity detector, and an injection volume of 25 μL.

[0013] The present invention also provides a method for preparing the above-mentioned crosslinked color-fixing agent, the method comprising the preparation of component A, the preparation of component B, and the two-component compounding steps, as detailed below: Preparation of component A: S1. Synthesis of polymer intermediates: Weigh raw materials according to the molar ratio of bio-based polycarboxylic acids and anhydrides to epoxy compounds of 1:2.8 to 1:3.2; add the bio-based polycarboxylic acids and anhydrides, catalyst and solvent to a reactor, wherein the catalyst is at least one of tetraethylammonium bromide and triethylamine, and the amount added is 0.5%-2% of the total mass of the bio-based polycarboxylic acids and anhydrides and epoxy compounds; the solvent is one of N,N-dimethylformamide and dimethyl sulfoxide; after stirring and dissolving at 50-60°C, add the epoxy compounds dropwise, and react at 70-85°C for 4-6 hours; S2. Preliminary post-treatment: Cool the reaction solution obtained in step S1 to room temperature, and distill under reduced pressure for 3-5 hours at a vacuum degree not exceeding 0.005 MPa and a temperature of 80-100℃ to obtain crude polymer intermediate. S3. Purification and Drying: Dissolve the crude intermediate obtained in step S2 in acetone, using 8-15 times the mass of the crude intermediate. Add the solution dropwise to 5-10 times the volume of acetone in diethyl ether while stirring to precipitate the product. Filter the solution. Dry the filtered solid at 40-50°C and a vacuum degree not exceeding 0.01 MPa to constant weight to obtain a polymer intermediate with a hydroxyl value of 80-150 mg KOH / g and a branching degree of 0.5-0.6. S4. Grafting reaction preparation: Dissolve the polymer intermediate obtained in step S3 in a mixed solvent of water and ethanol to prepare a clear solution with a mass fraction of 10%-15%, wherein the volume ratio of water to ethanol in the mixed solvent is between 6:4 and 8:2; cool to 45-55℃. S5, Quaternary ammonium salt side-linking: Add an alkaline catalyst and a polymerization inhibitor system containing hydroquinone and sodium sulfite to the solution from step S4, and then... Under stirring conditions at rpm, an aqueous solution of the quaternizing agent 3-chloro-2-hydroxypropyltrimethylammonium chloride is slowly added dropwise at a rate of 0.5%-1.0% per minute relative to the real-time volume of the reaction system. The real-time volume of the reaction system is the sum of the volume of the solution in step S4 and the volume of the added aqueous solution of the quaternizing agent. The reaction is carried out at 45-55°C for 3-4 hours, and the pH value of the reaction system is maintained at 9.5-10.5 by adding one of dilute hydrochloric acid and sodium hydroxide solution. The alkaline catalyst is one of sodium hydroxide and potassium hydroxide, and its addition amount is 1.0%-2.5% of the mass of the polymer intermediate. The amount of hydroquinone added as the polymerization inhibitor is 0.5%-2.0% of the mass of the quaternizing agent, and the amount of sodium sulfite added is 20%-40% of the mass of hydroquinone. The mass concentration of the aqueous solution of the quaternizing agent is 30%-60%, and its addition amount is between 0.2:1 and 0.4:1 based on the molar ratio of its concentration to the hydroxyl group of the polymer intermediate. S6. Purification and Product Preparation: After the reaction is completed, the reaction solution is purified by dialysis using a dialysis bag with a molecular weight cutoff of 1000 Da and deionized water as the dialysate. Dialysis is continued until the final external liquid conductivity is less than 20 μS / cm. Subsequently, the solution is freeze-dried to obtain a solid polymer product. The solid polymer product is mixed with water and prepared into an aqueous dispersion with a mass fraction of 15%-35% under shear dispersion. The dispersion shows no visible layering after standing at 25°C for 24 hours, thus obtaining component A. Preparation of component B: S7: Catalyst Formulation: Component B is in one of the following two forms: Stable complex morphology: Tetraisopropyl titanate and acetylacetone were stirred at room temperature for 1-3 hours to form a complex, yielding a clear and stable complex solution. Isopropanol solution form: Tetraisopropyl titanate is dissolved in isopropanol to prepare a solution with a mass fraction of 15%-25%. Two-component compound: S8. Working solution preparation: When using, under stirring conditions of 300-600 rpm, slowly add component B prepared in step S7 to component A prepared in step S6, wherein the mass ratio of polymer in component A to component B is 100:2 to 100:8. After the addition is completed, continue stirring and maturing for 10-30 minutes to obtain a uniform finishing working solution. S9. pH Adjustment and Quality Control: Add 0.1-0.3 mol / L acetate-sodium acetate buffer solution to the working solution obtained in step S8 to adjust and stabilize the pH value of the working solution at 4.0-6.0. The resulting working solution should be free of visible particles, and the turbidity measured at 660 nm at 25±2℃ should not exceed 10 NTU. It should be used up within 4 hours.

[0014] One of the advantages of this invention is that by using renewable raw materials as the core framework of hyperbranched polymers, the environmental friendliness and sustainability of the product source are guaranteed.

[0015] The second beneficial effect of this invention is that by precisely grafting cationic quaternary ammonium salt side chains onto a bio-based hyperbranched framework, a unique dual mechanism of hyperbranched physical network fixation and cationic chemical bonding is formed, achieving efficient and synergistic color fixation of polyester and cotton fibers.

[0016] The third beneficial effect of this invention is that by limiting the degree of branching, residual hydroxyl value and weight-average molecular weight range of the polymer, it ensures that the polymer has good water dispersibility, sufficient film-forming properties and reactivity, as well as suitable fabric permeability, thereby improving color fixation uniformity and protecting the fabric hand feel.

[0017] The fourth beneficial effect of this invention is that by adopting a two-component design, it solves the industry pain point of poor storage stability and easy failure of single-component systems containing catalysts, thereby improving the shelf life and application reliability of the product.

[0018] The fifth beneficial effect of this invention is that by using a titanate-acetylacetone complex as a crosslinking catalyst and cooperating with an acetate-sodium acetate buffer system, polymer crosslinking can be activated under mild and weakly acidic conditions, avoiding damage to the fabric caused by high-temperature and strong alkali treatment, and demonstrating excellent process applicability.

[0019] The sixth beneficial effect of this invention is that by introducing nuclear magnetic resonance hydrogen spectroscopy to accurately determine the degree of branching and grafting conversion rate, ion chromatography to monitor the content of inorganic salts, and a strict dialysis purification process into the preparation method, the controllability of the polymer product structure and the stability between batches are ensured, thereby improving the reproducibility of the technology and its industrialization prospects.

[0020] The seventh beneficial effect of this invention is that by limiting the turbidity and aging time of the finishing working solution, the uniformity and activity of the application solution are ensured, and the reproducibility of the color-fixing effect is improved. Attached Figure Description

[0021] Figure 1 This is a flowchart of a method for preparing a cross-linked color-fixing auxiliary agent to improve the color fastness of polyester-cotton blended fabrics according to the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.

[0023] Example 1: Preparation of bio-based hyperbranched polymers: This embodiment aims to illustrate in detail the complete preparation process of a two-component system comprising a bio-based hyperbranched polymer and an organometallic complex catalyst. The prepared polymer is the core material for forming the aqueous dispersion with stable storage properties in this two-component system. Specifically, this embodiment selects bio-based polycarboxylic acids and epoxy compounds as starting materials, and constructs the hyperbranched framework of the polymer through a ring-opening addition reaction.

[0024] A method for preparing a cross-linked color-fixing auxiliary agent to improve the color fastness of polyester-cotton blended fabrics. Preparation of component A: Materials and detailed proportions: Polymer intermediate synthesis: Bio-based polycarboxylic acid: citric acid (C6H8O7), 192.1 g (1.0 mol).

[0025] Epoxide compound: epichlorohydrin, 324.0 g (approximately 3.5 mol).

[0026] Catalyst: Tetraethylammonium bromide, 8.0 g.

[0027] Solvent: N,N-dimethylformamide (DMF), 400 mL.

[0028] Purification reagents: 400 mL acetone, 4 L diethyl ether.

[0029] Quaternary ammonium salt lateral linking branches: Polymer intermediate (homemade): 150 g.

[0030] Mixed solvents: 840 mL deionized water and 360 mL anhydrous ethanol.

[0031] Alkaline catalyst: Sodium hydroxide, 3.0 g.

[0032] Polymerization inhibitor system: hydroquinone 1.8 g, sodium sulfite 0.5 g.

[0033] Quaternization reagent: 50% aqueous solution of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 132.6 g.

[0034] Preparation method: S1. Synthesis and purification of polymer intermediates: Citric acid, tetraethylammonium bromide, and DMF were added to the reactor and stirred at 60°C to dissolve. Epichlorohydrin was slowly added dropwise, controlling the reaction temperature at 80±2°C. After the addition was complete, the reaction continued for 5 hours.

[0035] S2. Preliminary post-treatment: After the reaction solution is cooled, it is distilled under reduced pressure at 0.003 MPa and 90℃ for 4 hours to obtain the crude product.

[0036] S3. Purification and Drying: The crude product was dissolved in acetone and added dropwise to diethyl ether with stirring to precipitate the product, which was then filtered. The solid was dried under vacuum at 45°C and 0.008 MPa to constant weight to obtain 315 g of white polymer intermediate powder.

[0037] S4. Grafting reaction preparation: Dissolve 150 g of the intermediate in a water-ethanol mixed solvent to prepare a clear solution with a mass fraction of about 12.5%, and cool it to 50°C.

[0038] S5, Quaternary ammonium salt side-linking: Add sodium hydroxide, hydroquinone, and sodium sulfite. While stirring at 600 rpm, slowly add the aqueous solution of the quaternizing reagent dropwise, maintaining the pH of the reaction system at 10.0 ± 0.2 by adding dilute hydrochloric acid. After the addition is complete, continue the reaction at 50°C for 3.5 hours.

[0039] S6. Purification and Product Preparation: The reaction solution was transferred to a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed with deionized water until the conductivity of the external solution was below 20 μS / cm. After pre-freezing the dialysate at -70℃, it was freeze-dried under a vacuum of less than 0.001 MPa for 20 hours to obtain 162 g of white solid product. This solid product was prepared into a 30% (w / w) aqueous dispersion. After standing at 25℃ for 24 hours, no visible layering was observed, thus obtaining the stock solution of component A.

[0040] Product characterization: Residual hydroxyl value: 51 mg KOH / g.

[0041] Branching degree: 0.58.

[0042] Weight-average molecular weight (GPC): 25,000.

[0043] Grafting conversion rate: 78%.

[0044] Total inorganic salt content: 0.12% w / w.

[0045] Preparation of component B: Materials and proportions: Tetraisopropyl titanate: 17.0 g.

[0046] Acetylacetone: 18.0 g.

[0047] Molar ratio: 1:3.

[0048] Preparation method: S7. Catalyst preparation: Under nitrogen protection, acetylacetone was added dropwise to tetraisopropyl titanate and stirred at room temperature for 2 hours to obtain a clear yellow complex solution, i.e. component B-1.

[0049] Two-component compound: S8. Working solution preparation: Take 100 g of component A stock solution (30%) and slowly add 4.5 g of component B-1 catalyst dropwise while stirring at 400 rpm. After the addition is complete, continue stirring and maturing for 20 minutes to obtain a homogeneous working solution.

[0050] S9. pH Adjustment and Quality Control: After aging, add 0.2 mol / L acetate-sodium acetate buffer solution to the working solution to adjust and stabilize the pH value of the working solution at 5.0.

[0051] The resulting working solution was clear and transparent, with no visible particles. The turbidity was measured at 25°C to be 6 NTU.

[0052] The working fluid should be used within 4 hours as required.

[0053] Test results: Wash fastness (ISO 105-C06): Color change grade 4-5, cotton staining grade 4-5, polyester staining grade 4-5.

[0054] Fastness to wet rubbing (ISO 105-X12): Grade 4.

[0055] Fabric feel: It basically retains its original softness.

[0056] Component A in Example 2 uses itaconic anhydride: This embodiment serves as the experimental group, demonstrating the feasibility and applicability of using acid anhydrides and corresponding catalytic systems for component A.

[0057] Preparation of component A: Materials and detailed proportions: Bio-based acid anhydride: Itaconic anhydride (C5H4O3), 112.1 g.

[0058] Epichlorohydrin, 305.0 g.

[0059] Catalyst: Triethylamine, 10.2 g.

[0060] Solvent: Dimethyl sulfoxide, 300 mL.

[0061] Polymer intermediate: 120 g.

[0062] Mixed solvent: deionized water and anhydrous ethanol, volume ratio 6:4.

[0063] Alkaline catalyst: potassium hydroxide, 2.4 g.

[0064] Polymerization inhibitor system: hydroquinone 1.5 g, sodium sulfite 0.4 g.

[0065] Quaternizing reagent: 50% aqueous solution, 114.5 g.

[0066] Preparation method: Synthesis of intermediates S1-S3: The steps were the same as in Example 1, but the reaction temperature was controlled at 75±3℃ and the reaction time was 4.5 hours. The final intermediate obtained had a hydroxyl value of 138 mg KOH / g and a branching degree of 0.51.

[0067] S4-S6 side grafting and purification: The steps were the same as in Example 1, with the reaction pH controlled at 9.8±0.2, the reaction temperature at 50℃, and the reaction time at 4 hours. A solid polymer was finally obtained.

[0068] Preparation of component A: The solid product was prepared into an aqueous dispersion with a mass fraction of 30%. After testing at 25℃ for 24h, no stratification was observed, thus obtaining itaconic anhydride-based component A.

[0069] Preparation of component B: Step S7 catalyst preparation is the same as in Example 1, preparing component B-1.

[0070] Two-component compounding and application: Following steps S8-S9 of Example 1, 100g of itaconic anhydride-based component A was taken and 4.5g of component B-1 was added to obtain a working solution with pH=5.0 and turbidity of 7 NTU.

[0071] Application Results: Under the same fabric and processing conditions as in Example 1, the test results were: wet rubbing fastness grade 4, soap washing fastness grade 4-5, and good hand feel. This confirms that itaconic anhydride is a completely feasible alternative raw material.

[0072] Example 3: Optimization of Quaternization Reagent Dosage Ratio: This embodiment serves as the experimental group, focusing on investigating the effect of the molar ratio of quaternizing reagent to polymer intermediate hydroxyl group on the grafting conversion rate and final performance of the product, in order to verify and optimize the process parameters.

[0073] Preparation of component A: Materials and detailed proportions: Common raw materials: Polymer intermediates obtained by the same preparation method as in Example 1, three portions of 100 g each.

[0074] Dosage of quaternizing reagent: Group A-3: 66.3 g.

[0075] Group B-3: 99.5 g.

[0076] Group C-3: 132.6 g.

[0077] Other auxiliaries are adjusted according to the proportions specified in this invention and the amount of quaternizing reagent used: NaOH: Group A-3 1.5g, Group B-3 2.0g, Group C-3 2.5g.

[0078] Hydroquinone: Group A-3 1.2g, Group B-3 1.5g, Group C-3 2.0g.

[0079] Sodium sulfite: Group A-3 0.3g, Group B-3 0.4g, Group C-3 0.6g.

[0080] The intermediate solution with a mass fraction of 15% was prepared using a mixture of water and ethanol in a ratio of 7:3.

[0081] Preparation method: Synthesis of S1-S3 intermediates: The steps are the same as in Example 1. S4-S6 Lateral Branching and Purification: The three groups of experiments were conducted independently according to the detailed steps of S4-S6 in Example 1. All reaction conditions were kept consistent: 50°C, pH 10.0±0.2, and a total reaction time of approximately 4 hours.

[0082] After dialysis and lyophilization, three solid polymer products were obtained.

[0083] The three products were prepared into aqueous dispersions with a mass fraction of 30%, and after standing for 24 hours, no stratification was observed, resulting in three different components A (A-3, B-3, C-3).

[0084] Preparation of component B: The S7 catalyst was prepared in the same manner as in Example 1, with the same preparation component B-1.

[0085] Two-component compounding and application: Following steps S8-S9 of Example 1, 100g each of components A-3, B-3, and C-3 were taken, and 4.5g of component B-1 was added to each to prepare three working solutions with a pH of 5.0. The turbidity of all three working solutions was between 5 and 8 NTU.

[0086] Results and Discussion: The grafting conversion rate was determined by the aforementioned proton nuclear magnetic resonance spectroscopy, and the residual hydroxyl value was calculated according to the formula.

[0087] The results are shown in the table below: ; Conclusion: A feed ratio of 0.3:1 yielded the highest grafting conversion rate and a moderate residual hydroxyl value. This indicates that this ratio represents the optimal process conditions, validating the rationality of the parameter range.

[0088] Example 4: Verification of catalyst type and formulation ratio: This embodiment serves as the experimental group, focusing on demonstrating the effect of combining the prepared component A with component B catalysts of different forms and amounts on the working fluid state and application performance.

[0089] Preparation of component A: Solid polymers were prepared according to steps S1-S6 in Example 1 and uniformly formulated into an aqueous dispersion with a mass fraction of 30%, which served as component A in this experiment.

[0090] Preparation of component B B-1: The preparation method is the same as in Example 1.

[0091] B-2 isopropanol solution: Materials: 25 g tetraisopropyl titanate, 75 g anhydrous isopropanol.

[0092] Method: Simply stir and mix the two in a beaker to obtain a 25% tetraisopropyl titanate isopropanol solution, which is used as component B-2.

[0093] Two-component compounding and application: S8. Working solution preparation: Following the steps in Example 1, with component A fixed at 100g, the following three sets of experiments were designed: Group D: 1.5 g of catalyst B-1 was slowly added dropwise to component A while stirring at 400 rpm.

[0094] Group E: 0.6 g of catalyst B-1 was slowly added dropwise to component A while stirring at 400 rpm.

[0095] Group F: 2.4 g of B-2 catalyst was slowly added dropwise to component A while stirring at 400 rpm.

[0096] All groups were cooked for 20 minutes.

[0097] S9. pH Adjustment and Quality Control: After aging, adjust the pH to 5.0 using 0.2 M acetate-sodium acetate buffer.

[0098] Application effect: The above working solution was used to impregnate and bake the dyed polyester-cotton fabric.

[0099] The results showed that the fabric fastness of groups D and E was significantly improved, with group D showing better results. Group F had comparable colorfastness, but the hand feel was slightly inferior.

[0100] Conclusion: By preferentially using B-1 type stable complex catalyst and controlling the addition amount to maintain a polymer-to-catalyst mass ratio within the range of 100:2 to 100:8, a clear and stable working solution with turbidity ≤10 NTU and excellent color-fixing effect can be obtained. This verifies the technical necessity of the requirements for catalyst type, compounding ratio, and working solution turbidity.

[0101] Example 5 Comparison with commercially available products: This embodiment serves as a control group, aiming to demonstrate the comprehensive advantages of the present invention's technical solution by comparing its cross-linking color-fixing agent with commercially available conventional products in parallel applications.

[0102] Sample preparation for this invention: Component A: The solid polymer prepared by the method of Example 1 was formulated into a 30% aqueous dispersion.

[0103] Component B: B-1 catalyst prepared using the method of Example 1.

[0104] Two-component compounding: Accurately weigh 100g of component A, add 1.5g of component B while stirring, and follow steps S8-S9 of Example 1. After aging, adjust the pH to 5.0 to obtain a clear working solution with a turbidity of 6 NTU.

[0105] For a fair comparison, this working solution was diluted with deionized water to the same concentration recommended for the control group.

[0106] Control group samples: Product: A commercially available brand of reactive cationic color-fixing agent.

[0107] Preparation: Strictly follow the product instructions, weigh out a certain amount of fixing agent, and prepare a working solution with deionized water to a concentration of 30 g / L. Adjust the pH of the working solution to 5.5 with glacial acetic acid.

[0108] Test fabric: Dark black polyester-cotton woven fabric dyed in the same batch.

[0109] Application process: Both processes use the same two-dip, two-roll process, pre-drying at 110℃ for 2 minutes, and baking at 160℃ for 90 seconds.

[0110] Test result comparison: ; in conclusion: Compared with commercially available conventional products, the two-component cross-linked color-fixing auxiliary of this invention exhibits significant advantages in various aspects of color fastness, especially in improving the most challenging aspect: wet rubbing fastness. Simultaneously, its unique hyperbranched structure and mild catalytic system effectively solve the problem of fabric stiffening caused by traditional color-fixing agents, better preserving the original soft hand feel of the fabric. This comparative experiment powerfully demonstrates the inventiveness, advancement, and comprehensive practicality of the technical solution of this invention.

[0111] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics, characterized in that, It is a two-component system comprising a bio-based hyperbranched polymer and an organometallic complex catalyst, wherein: Component A: An aqueous dispersion of the bio-based hyperbranched polymer; the polymer mass fraction in the aqueous dispersion is 15%-35%, and no visible stratification is observed after standing at 25°C for 24 hours; Component B: A stabilized organometallic complex catalyst, which is a stable complex formed by the complexation of tetraisopropyl titanate and acetylacetone in a molar ratio of 1:2 to 1:4, and a solution of tetraisopropyl titanate isopropanol with a mass fraction of 15%-25%. In this process, component B is slowly added dropwise to component A under stirring at 300-600 rpm. After mixing, the mixture is allowed to mature for 10-30 minutes to obtain a homogeneous finishing working solution with no visible particles and a turbidity of no more than 10 NTU measured at 660 nm at 25±2℃. The pH of the working solution is adjusted and stabilized at 4.0-6.0 by adding 0.1-0.3 mol / L acetate-sodium acetate buffer. The working solution should be used within 4 hours. The mass ratio of the polymer in component A to component B is between 100:2 and 100:

8.

2. The cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics according to claim 1, characterized in that, The bio-based hyperbranched polymer is prepared by a ring-opening addition reaction of one of bio-based polycarboxylic acids and acid anhydrides with an epoxy compound; the bio-based polycarboxylic acid is a tricarboxylic acid; and the epoxy compound is epichlorohydrin.

3. The cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics according to claim 1, characterized in that, The polymer product has a water content of no more than 1.0% w / w and a total inorganic salt content of less than 0.2% w / w. The total inorganic salt content is determined by ion chromatography. The ion chromatography conditions are as follows: anion exchange column IonPac AS11-HC (4×250 mm) and cation exchange column IonPac CS12A (4×250 mm) are used, the eluents are KOH solution and 20 mM methanesulfonic acid solution, respectively, a suppressed conductivity detector is used, and the injection volume is 25 μL.

4. The cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics according to claim 1, characterized in that, The bio-based hyperbranched polymer has grafted cationic quaternary ammonium salt side chains, with a residual hydroxyl value of not less than 40 mg KOH / g, a branching degree of 0.5-0.65, and a weight-average molecular weight of 8000-40000.

5. The cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics according to claim 4, characterized in that, The grafting conversion rate of the quaternary ammonium salt side chain of the grafted cation was determined by proton nuclear magnetic resonance spectroscopy. Specifically, it was calculated by comparing the integral area ratio of the single peak of the grafted polymer at a chemical shift of 3.25 ppm to that at a chemical shift of 3.85 ± 0.05 ppm, which is attributed to the hydrogen of the specific methylene structure (-O-CH2-CH(OH)-CH2-) in the main chain. The residual hydroxyl value was calculated based on the grafting conversion rate, the amount of quaternizing reagent added, and the formula: Residual hydroxyl value = Intermediate hydroxyl value - (Moles of quaternizing reagent added × Grafting conversion rate × 56100) / Net mass of polymer after deducting inorganic salts, where the net mass of polymer is the mass of the solid product obtained after freeze-drying in step S6.

6. The cross-linking color-fixing auxiliary agent for improving the color fastness of polyester-cotton blended fabrics according to claim 1, characterized in that, The degree of branching of the polymer was determined by proton nuclear magnetic resonance spectroscopy, specifically using one of the following solvents: deuterated water or a mixture of deuterated water and deuterated methanol in a 1:1 volume ratio. The branching degree was calculated using the formula: branching degree = (I branch / I total ) calculate, where I branch The integral area of ​​the hydrogen attributable to the branching sites of the polymer backbone in the chemical shift range of 2.6–3.2 ppm is the sum of the integral area of ​​the hydrogen attributable to the terminal quaternary ammonium salt methyl (-N+(CH3)3) hydrogen at the chemical shift of 3.25 ppm. The integral boundaries of the two peak areas were accurately separated by Lorentz peak shape fitting using MestReNova. total The integral area is the sum of all peak intensities not less than 2% of the intensity of the strongest polymer characteristic peak in the range of chemical shift 1.0-5.0 ppm, which can be clearly attributed to the polymer backbone and side chain hydrogens. The integral of the residual water peak at chemical shift 4.79 ppm needs to be subtracted by measuring the spectrum of the blank solvent under the same conditions.

7. A method for preparing the crosslinking fixing agent according to any one of claims 1-6, characterized in that, The method includes the preparation of component A, the preparation of component B, and the two-component compounding steps, as detailed below: Preparation of component A: S1. Synthesis of polymer intermediates: Weigh raw materials according to the molar ratio of bio-based polycarboxylic acids and anhydrides to epoxy compounds of 1:2.8 to 1:3.2; add the bio-based polycarboxylic acids and anhydrides, catalyst and solvent to a reactor, wherein the catalyst is at least one of tetraethylammonium bromide and triethylamine, and the amount added is 0.5% to 2% of the total mass of the bio-based polycarboxylic acids and anhydrides and epoxy compounds; the solvent is one of N,N-dimethylformamide and dimethyl sulfoxide; after stirring and dissolving at 50-60°C, add the epoxy compounds dropwise, and react at 70-85°C for 4-6 hours; S2. Preliminary post-treatment: Cool the reaction solution obtained in step S1 to room temperature, and distill under reduced pressure for 3-5 hours at a vacuum degree not exceeding 0.005 MPa and a temperature of 80-100℃ to obtain crude polymer intermediate. S3. Purification and Drying: Dissolve the crude intermediate obtained in step S2 in acetone, using 8-15 times the mass of the crude intermediate. Add the solution dropwise to 5-10 times the volume of acetone in diethyl ether while stirring to precipitate the product. Filter the solution. Dry the filtered solid at 40-50°C and a vacuum degree not exceeding 0.01 MPa to constant weight to obtain a polymer intermediate with a hydroxyl value of 80-150 mg KOH / g and a branching degree of 0.5-0.

6. S4. Grafting reaction preparation: Dissolve the polymer intermediate obtained in step S3 in a mixed solvent of water and ethanol to prepare a clear solution with a mass fraction of 10%-15%, wherein the volume ratio of water to ethanol in the mixed solvent is 6:4 to 8:2; cool to 45-55℃. S5, Quaternary ammonium salt side-linking: Add an alkaline catalyst and a polymerization inhibitor system containing hydroquinone and sodium sulfite to the solution from step S4, and then... Under stirring conditions at rpm, an aqueous solution of the quaternizing agent 3-chloro-2-hydroxypropyltrimethylammonium chloride is slowly added dropwise at a rate of 0.5%-1.0% per minute relative to the real-time volume of the reaction system. The real-time volume of the reaction system is the sum of the volume of the solution in step S4 and the volume of the added aqueous solution of the quaternizing agent. The reaction is carried out at 45-55°C for 3-4 hours, and the pH value of the reaction system is maintained at 9.5-10.5 by adding one of dilute hydrochloric acid and sodium hydroxide solution. The alkaline catalyst is one of sodium hydroxide and potassium hydroxide, and its addition amount is 1.0%-2.5% of the mass of the polymer intermediate. The amount of hydroquinone added as the polymerization inhibitor is 0.5%-2.0% of the mass of the quaternizing agent, and the amount of sodium sulfite added is 20%-40% of the mass of hydroquinone. The mass concentration of the aqueous solution of the quaternizing agent is 30%-60%, and its addition amount is between 0.2:1 and 0.4:1 based on the molar ratio of its concentration to the hydroxyl group of the polymer intermediate. S6. Purification and Product Preparation: After the reaction is completed, the reaction solution is purified by dialysis using a dialysis bag with a molecular weight cutoff of 1000 Da and deionized water as the dialysate. Dialysis is continued until the final external liquid conductivity is less than 20 μS / cm. Subsequently, the solution is freeze-dried to obtain a solid polymer product. The solid polymer product is mixed with water and prepared into an aqueous dispersion with a mass fraction of 15%-35% under shear dispersion. The dispersion shows no visible layering after standing at 25°C for 24 hours, thus obtaining component A. Preparation of component B: S7. Catalyst preparation: Component B is in one of the following two forms: Stable complex morphology: Tetraisopropyl titanate and acetylacetone were stirred at room temperature for 1-3 hours to form a complex, yielding a clear and stable complex solution. Isopropanol solution form: Tetraisopropyl titanate is dissolved in isopropanol to prepare a solution with a mass fraction of 15%-25%. Two-component compound: S8. Working solution preparation: Under stirring conditions of 300-600 rpm, the component B prepared in step S7 is slowly added dropwise to the component A prepared in step S6, wherein the mass ratio of the polymer in component A to component B is 100:2 to 100:

8. After the addition is completed, continue stirring and maturing for 10-30 minutes to obtain a uniform finishing working solution. S9. pH Adjustment and Quality Control: Add 0.1-0.3 mol / L acetate-sodium acetate buffer solution to the working solution obtained in step S8 to adjust and stabilize the pH value of the working solution at 4.0-6.

0. The resulting working solution should be free of visible particles, and the turbidity measured at 660 nm at 25±2℃ should not exceed 10 NTU. It should be used up within 4 hours.

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