A formaldehyde-free fixing agent based on triazine-latent isocyanate functional monomer and a preparation method thereof

Abstract

This application belongs to the field of organic synthesis and discloses a formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer. It is prepared from triazine-latent isocyanate functional monomer (TLI monomer), dimethyl diallyl ammonium chloride (DMDAAC), and diallylamine as raw materials; the mass ratio of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 10~30:30~48:10. This fixing agent uses the TLI monomer, which simultaneously integrates a triazine structure, hydroxyl groups, polymeric double bonds, and latent isocyanate groups, as its core. Through copolymerization with DMDAAC and diallylamine, a triple synergistic fixing system of "electrostatic adsorption-hydrogen bond anchoring-covalent crosslinking" is constructed, breaking through the performance bottleneck of traditional formaldehyde-free fixing agents in terms of wet rubbing fastness, and significantly improving the wet rubbing fastness of sensitive colors such as bright red and turquoise blue.

Description

Technical Field

[0001] This invention relates to the fields of organic synthesis and textile chemicals, and in particular to a high-performance formaldehyde-free color-fixing agent based on a novel triazine-latent isocyanate functional monomer and its preparation method. Background Technology

[0002] Currently, wet rubbing fastness improvers on the market are mainly polyurethane or formaldehyde-containing resins. Although they can significantly improve wet rubbing fastness, they have problems such as poor environmental friendliness, easy yellowing, and a hard feel. Formaldehyde-free fixing agents, represented by quaternary ammonium salt polymers, are environmentally friendly, but they mainly rely on electrostatic effects, which are relatively weak. Therefore, their effect on improving wet rubbing fastness is limited, especially for sensitive colors such as bright red and turquoise blue, where they are difficult to meet export standards.

[0003] Existing technologies (such as CN116376013B) have proposed color-fixing agents based on hyperbranched polyamide amines, utilizing their film-forming properties to improve color-fixing effects. However, their color-fixing mechanisms are still mainly based on physical adsorption and hydrogen bonding, and there is still room for improvement in performance when high-strength covalent crosslinking is required to achieve extreme wet rubbing fastness.

[0004] Therefore, the technical problem to be solved by this application is: how to design a novel molecular structure that integrates multiple color-fixing mechanisms within the same molecule, especially by introducing a high-strength covalent cross-linking ability that can be stored under mild conditions and triggered during heat treatment, thereby developing a formaldehyde-free color-fixing agent with comprehensive performance that surpasses existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer (TLI monomer). This fixing agent, through copolymerization of the TLI monomer with DMDAAC (dimethyl diallyl ammonium chloride) and diallylamine, constructs a triple synergistic fixing system integrating "strong electrostatic adsorption (quaternary ammonium salt), multi-point anchoring (triazine ring), and dynamic covalent crosslinking (latent isocyanate)." This system is stable before final heat treatment and triggers a high-strength crosslinking network during heat treatment, thereby achieving a breakthrough improvement in the wet rubbing fastness of sensitive colors, comparable to polyurethane-type products. Simultaneously, it overcomes the disadvantages of polyurethane products such as hard feel and poor hydrophilicity, while maintaining the advantages of being environmentally friendly, soft, and hydrophilic, and has good industrialization prospects.

[0006] In addition, the present invention also provides a method for preparing the formaldehyde-free fixing agent.

[0007] A formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer is prepared by free radical polymerization of triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine.

[0008] The mass ratio of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 10~30:30~48:10; preferably, the mass ratio of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 15~25:36~45:10; more preferably, the mass ratio of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 17~23:38~41:10.

[0009] The core of this invention lies in the use of a triazine-latent isocyanate functional monomer (TLI monomer), which is a multifunctional monomer synthesized through molecular design, and whose structure simultaneously includes:

[0010] 1. Triazine ring: Provides sites for forming strong hydrogen bonds and van der Waals forces with dye molecules (especially dyes containing sulfonic acid groups and amino groups), achieving "multi-point anchoring".

[0011] 2. Hydroxyl group: provides hydrophilicity and can serve as a potential auxiliary reaction site.

[0012] 3. Allyl double bond: can participate in free radical copolymerization reactions to integrate TLI monomers into the polymer backbone.

[0013] 4. Latent (terminated) isocyanate groups: Stable at room temperature, they are deactivated during fabric baking (e.g., 150-170°C), releasing highly reactive isocyanate groups (-NCO). These -NCO groups can react with the hydroxyl groups of cellulose, the active hydrogen groups of dye molecules, and the hydroxyl groups on polymer chains to form strong covalent bonds (urea bonds or urethane bonds), thereby constructing a three-dimensional cross-linked network.

[0014] While serving as a comonomer, TLI monomers also possess the following functions: film-forming crosslinking, covalent crosslinking, wet friction enhancement, and dye anchoring.

[0015] The structural characteristics of TLI monomers are as follows: a triazine ring serves as a rigid hydrophobic core, providing multiple interactions with dye molecules (hydrogen bonds, van der Waals forces); multiple hydroxyl groups are connected to impart hydrophilicity and reactive sites; allyl double bonds participate in copolymerization, introducing a polymer network; most importantly, the terminal isocyanate groups are stable at room temperature, but are deactivated during fabric drying (e.g., above 150°C), releasing highly reactive isocyanate groups (-NCO), which can undergo irreversible covalent cross-linking reactions with hydroxyl and amino groups on the fiber, as well as dye molecules.

[0016] When used as the main core framework of the fastness enhancer, the fastness enhancer of the present invention has the functional characteristics shown in Table 1.

[0017] Table 1 Functional characteristics of fastness improvers

[0018] Function mechanism Actual test results ① Dye anchoring and adsorption The triazine ring forms strong hydrogen bonds and van der Waals forces with the dye sulfonic acid / amino groups, while the quaternary ammonium salt provides strong electrostatic adsorption. Dye adsorption rate >95%, soaping solution color ↓75% ② Improved wet friction When dried at 100-110 °C, the capped isocyanate is decapsulated, and the released -NCO forms a covalent cross-linked network with the fiber, dye, and its own hydroxyl groups, thus "chemically locking" the dye. Wet rubbing fastness increases by 1.5-2.5 grades (2 to 4 for bright red rub). ③ Film formation and encapsulation The copolymer forms a film on the fiber surface, where the rigid triazine structure of the TLI monomer combines with the flexible segments to form a continuous, dense, and tough film. Electron microscopy showed that the surface roughness Ra decreased from 35 nm to 10 nm. ④ Hand feel / hydrophilic balance By adjusting the TLI monomer feed ratio to control the crosslinking density, the retained hydroxyl groups and polymer backbone provide moderate hydrophilicity. Bending stiffness ↑ <10%, hydrophilicity 0s (instantaneous) → 5s (acceptable)

[0019] The aforementioned effects are achieved synergistically through free radical copolymerization of TLI monomer, DMDAAC, and diallylamine. TLI monomer provides anchoring and cross-linking centers, DMDAAC provides high-density cationic charges for rapid adsorption, and diallylamine provides auxiliary adsorption sites and modulates polymer chain properties. The combined effect of these components improves the wet rubbing fastness of the product by 1.5 to 2.5 grades, reaching grade 4 or higher, comparable to polyurethane. It also has excellent color fastness, with significant improvements in soaping and perspiration fastness. It is particularly effective for sensitive colors such as bright red and turquoise blue. It does not affect the color, has a soft feel, good hydrophilicity, and strong process adaptability.

[0020] In the above-mentioned formaldehyde-free fixing agent based on triazine-latent isocyanate functional monomers, the triazine-latent isocyanate functional monomers are synthesized through the following steps:

[0021] Step 1: In a polar aprotic solvent, under nitrogen protection and in the presence of a polymerization inhibitor, melamine is reacted with an excess of allyl glycidyl ether at 110-130°C for 6-12 hours to generate intermediate A containing a triazine core, multiple hydroxyl groups and multiple allyl double bonds.

[0022] Step 2: At 0~10℃, under anhydrous and inert atmosphere, isophorone diisocyanate is reacted with an equimolar amount of the capping agent butanone oxime to selectively cap the primary isocyanate group of isophorone diisocyanate, to obtain intermediate B of single-capped IPDI retaining a secondary isocyanate group.

[0023] Step 3: In an inert solvent, intermediate A and intermediate B are reacted at 30-60°C for 12-24 hours. The secondary isocyanate group of intermediate B is linked to some of the secondary amine or hydroxyl groups on intermediate A to finally obtain the triazine-latent isocyanate functional monomer.

[0024] In the above-mentioned formaldehyde-free fixing agent based on triazine-latent isocyanate functional monomers, the fixing agent is a water-soluble or water-dispersible polymer obtained by free radical copolymerization, with a weight-average molecular weight of 50,000~300,000 g / mol, preferably 80,000~200,000 g / mol, and more preferably 120,000~180,000 g / mol.

[0025] In the above-mentioned formaldehyde-free fixing agent based on triazine-latent isocyanate functional monomers, the inert solvent is one or more combinations of anhydrous tetrahydrofuran, anhydrous acetone, and anhydrous acetonitrile; the weight ratio of the inert solvent to the total weight of intermediate A and intermediate B is 200~300:100.

[0026] In the above-mentioned formaldehyde-free fixing agent based on triazine-latent isocyanate functional monomer, the molar ratio of intermediate A to intermediate B is 0.9~1.1:0.9~1.1.

[0027] More specifically, the preparation method of TLI monomers includes the following steps:

[0028] Step S1: Dissolve melamine in dimethyl sulfoxide (DMSO), add polymerization inhibitor, heat to 115~125℃ under nitrogen protection and stir to dissolve;

[0029] Step S2: Mix allyl glycidyl ether (AGE) with the catalyst triethylamine and slowly add it dropwise to the reaction system of step 1, controlling the dropwise addition time to 2-3 hours and maintaining the reaction temperature at 115-125℃;

[0030] Step S3: After the addition is complete, continue stirring the reaction at 115~125℃ for 6~10 hours;

[0031] Step S4: Cool the reaction system to below 50°C, pour it into ice water with stirring to precipitate, filter, wash the filter cake with water, and vacuum dry at 40~50°C to obtain intermediate A containing a triazine core, multiple hydroxyl groups and multiple allyl double bonds;

[0032] Step S5: Dissolve isophorone diisocyanate (IPDI) in anhydrous acetone and cool it to 0~5°C in an ice-salt bath under nitrogen protection;

[0033] Step S6: Dissolve methyl ethyl ketone oxime in anhydrous acetone and slowly add it dropwise to the IPDI solution from step 5, controlling the dropwise addition time to 1-2 hours and maintaining the reaction temperature at 0-5°C;

[0034] Step S7: After the addition is complete, continue stirring the reaction at 0~5℃ for 3~5 hours;

[0035] Step S8: Monitor the intensity change of the -NCO characteristic peak (~2270 cm⁻¹) in the reaction system by Fourier transform infrared spectroscopy (FT-IR). Stop the reaction when the peak intensity drops to 45%~55% of the initial value. Remove the solvent by vacuum distillation to obtain single-terminated IPDI intermediate B.

[0036] Step S9: Dissolve intermediate A in anhydrous tetrahydrofuran (THF) and stir under nitrogen protection;

[0037] Step S10: Dissolve intermediate B in anhydrous THF and slowly add it dropwise to the intermediate A solution from step 9, controlling the dropwise addition time to 1-2 hours and maintaining the system temperature at 25-35℃;

[0038] Step S11: After the addition is complete, continue stirring the reaction at 25~35℃ for 20~28h;

[0039] Step S12: After the reaction is complete, tetrahydrofuran is removed by vacuum distillation to obtain a pale yellow to amber paste or viscous liquid, which is the triazine-latent isocyanate functional monomer (TLI monomer).

[0040] In step S1, the amount of melamine is 12.0 to 13.0 parts, the amount of DMSO is 140 to 160 parts, and the amount of hydroquinone, the polymerization inhibitor, is 0.5% to 1.5% of the weight of melamine.

[0041] In the above preparation method, in step S2, the amount of allyl glycidyl ether is 48.0~54.0 parts, and its molar ratio with melamine in step 1 is 3.5~4.5:1; the amount of triethylamine catalyst is 3%~5% of the weight of allyl glycidyl ether.

[0042] In the above preparation method, in step S5, the amount of IPDI used is 21.0~23.0 parts, and the amount of anhydrous acetone used is 90~110 parts.

[0043] In the above preparation method, in step S6, the amount of butanone oxime is 10.0~11.0 parts, and its molar ratio with IPDI in step 5 is 0.95~1.05:1; the amount of anhydrous acetone used for dissolution is 18~22 parts.

[0044] In the above preparation method, in step S9, the amount of intermediate A is 9.0~11.0 parts, and the amount of anhydrous THF is 45~55 parts.

[0045] In the above preparation method, in step S10, the amount of intermediate B is 6.0~7.5 parts, and its molar ratio with intermediate A in step 9 is 0.9~1.1:1 based on the theoretical amino content of intermediate A; the amount of anhydrous THF used for dissolution is 18~22 parts.

[0046] In the above preparation method, the vacuum distillation conditions in steps S4 and S8 are: temperature not exceeding 60°C and vacuum degree not lower than -0.085 MPa.

[0047] Meanwhile, this invention also discloses a method for preparing a formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer as described above, comprising the following steps:

[0048] Step 1: Dissolve the triazine-latent isocyanate functional monomer in deionized water, heat to 70~80℃, and protect with nitrogen.

[0049] Step 2: Add dropwise a mixed monomer aqueous solution of dimethyl diallyl ammonium chloride and diallylamine, while simultaneously adding a water-soluble initiator aqueous solution, controlling the total dropping time to 2-4 hours;

[0050] Step 3: After the addition is complete, keep the temperature at 70~80℃ for 1~3 hours to allow the reaction to proceed;

[0051] Step 4: Cool down to below 40℃, adjust pH to 5.0~7.0, discharge the material, and obtain the product.

[0052] In the above preparation method, the ratio of the total weight of deionized water in steps 1 and 2 to the total weight of triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 150~250:100.

[0053] In the above preparation method, the initiator is one of ammonium persulfate, potassium persulfate, or azobisisobutyramidine hydrochloride; the amount of the initiator is equivalent to 1-3 wt% of the total weight of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine.

[0054] The beneficial effects of this application are:

[0055] This invention designs and synthesizes a novel triazine-latent isocyanate functional monomer (TLI) and copolymerizes it with a cationic monomer to construct a triple color-fixing system of "adsorption-anchoring-covalent locking". This system breaks through the bottleneck of wet rubbing fastness of traditional formaldehyde-free color-fixing agents, significantly improves the wet rubbing fastness of sensitive colors, and achieves results comparable to polyurethane products. At the same time, it maintains the advantages of being environmentally friendly, soft, and hydrophilic, and has good prospects for industrialization.

[0056] This invention integrates multiple color-fixing mechanisms into a single formaldehyde-free molecule through an integrated molecular design of "triazine anchoring + latent crosslinking", achieving a breakthrough in wet rubbing fastness of highly sensitive colors. It also has excellent feel and hydrophilicity, and can completely replace polyurethane / formaldehyde wet rubbing enhancers. Detailed Implementation

[0057] The present invention will now be clearly and completely described in conjunction with embodiments thereof. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0058] Before describing the preparation method of the fastness enhancer of the present invention, the preparation method of the TLI monomer is first described. Specifically, the preparation method includes the following steps:

[0059] Step 1: Dissolve 12.6g of melamine in 150g of dimethyl sulfoxide (DMSO), add 0.15g of polymerization inhibitor (hydroquinone), and heat to 115~125℃ under nitrogen protection while stirring to dissolve;

[0060] Step 2: Mix 51.0g of allyl glycidyl ether (AGE) with 2.0g of triethylamine catalyst, and slowly add the mixture dropwise to the reaction system of Step 1, controlling the dropwise addition time to 2h and maintaining the reaction temperature at 120℃;

[0061] Step 3: After the addition is complete, continue stirring at 120℃ for 8 hours;

[0062] Step 4: Cool the reaction system to below 50°C, pour it into ice water with stirring to precipitate, filter, wash the filter cake with water, and vacuum dry at 40~50°C to obtain intermediate A containing a triazine core, multiple hydroxyl groups and multiple allyl double bonds;

[0063] Step 5: Dissolve 22.2g of isophorone diisocyanate (IPDI) in 100g of anhydrous acetone and cool to 0~5℃ in an ice-salt bath under nitrogen protection;

[0064] Step 6: Dissolve 10.1g of butanone oxime in 20g of anhydrous acetone and slowly add it dropwise to the IPDI solution from step 5, controlling the dropwise addition time to 1.5h and maintaining the reaction temperature at 0~5℃;

[0065] Step 7: After the addition is complete, continue stirring the reaction at 0~5℃ for 5 hours;

[0066] Step 8: Monitor the -NCO characteristic peak (~2270 cm⁻¹) in the reaction system using Fourier transform infrared spectroscopy (FT-IR). -1 The intensity change of the peak was observed, and the reaction was stopped when the peak intensity dropped to 45%~55% of the initial value. The solvent was removed by vacuum distillation to obtain the single-terminated IPDI intermediate B.

[0067] Step 9: Dissolve 10.0g of intermediate A in 50g of anhydrous tetrahydrofuran (THF) and stir under nitrogen protection;

[0068] Step 10: Dissolve 6.7g of intermediate B in 20g of anhydrous THF and slowly add it dropwise to the intermediate A solution from step 9, controlling the addition time to 2h and maintaining the system temperature at 30℃.

[0069] Step 11: After the addition is complete, continue stirring at 30°C for 24 hours;

[0070] Step 12: After the reaction is complete, tetrahydrofuran is removed by vacuum distillation to obtain a pale yellow to amber paste or viscous liquid, which is the triazine-latent isocyanate functional monomer (TLI monomer).

[0071] Example 1

[0072] Dissolve 20 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 39 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the dropwise addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0073] Example 2

[0074] Dissolve 15 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 42 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the dropwise addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0075] Example 3

[0076] Dissolve 30 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 33 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the dropwise addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0077] Example 4

[0078] Dissolve 10 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 45 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0079] Comparative Example 1

[0080] No TLI monomer added

[0081] 100 parts by weight of water were heated to 75°C, and 98 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine monomer mixture were added dropwise, along with 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the addition time to 3 hours. After the addition was complete, the reaction was maintained at this temperature for 2 hours. The temperature was then lowered to 40°C, the pH was adjusted to 6.0~7.0, and water was added to adjust the solid content of the system to 30±2%.

[0082] Comparative Example 2

[0083] Dissolve 40 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 30 parts by weight of DMDAAC solution (60% aqueous solution) and 10 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the dropwise addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0084] Comparative Example 3

[0085] Dissolve 20 parts by weight of TLI monomer in 100 parts by weight of water, heat to 75°C, and dropwise add 24 parts by weight of DMDAAC solution (60% aqueous solution) and 20 parts by weight of diallylamine mixed monomer, while simultaneously adding 2 parts by weight of ammonium persulfate (dissolved in 10 parts of water), controlling the dropwise addition time to 3 hours. After the addition is complete, maintain the reaction temperature for 2 hours. Cool down to 40°C, adjust the pH to 6.0~7.0, and add water to adjust the solid content of the system to 30±2%.

[0086] Comparative Example 4

[0087] Commercially available formaldehyde-free fixing agents have the following physical properties: They are pale yellow to amber transparent viscous liquids with a solid content of 40±2%, a pH value (1% aqueous solution) of 5.0-6.0, are readily soluble in water, and are cationic. The main component is a linear or slightly branched copolymer based on dimethyl diallyl ammonium chloride (DMDAAC) and acrylamide (AM). The cationic monomer (DMDAAC) chain segment content is approximately 50-60 mol%, providing electrostatic binding force with dye anions.

[0088] Comparative Example 5

[0089] This commercially available conventional polyurethane fixing agent has the following physical properties: It is a milky white emulsion with a bluish sheen, with a solid content of 35±1%, a pH value (1% aqueous solution) of 7.0-8.5, and good dispersibility in water. It is a nonionic / anionic type. The main component is an end-capped aqueous polyurethane dispersion synthesized from aliphatic isocyanate and polyether polyol. The end-capping agent is methyl ethyl ketone oxime.

[0090] Comparative Example 6

[0091] The process is largely the same as in Example 1, except that the latent isocyanate functional monomer used does not contain a triazine group. The specific preparation method is as follows:

[0092] Step 1: Dissolve 22.2g of isophorone diisocyanate (IPDI) in 100g of anhydrous acetone and cool to 0~5℃ in an ice-salt bath under nitrogen protection;

[0093] Step 2: Dissolve 8.7g of butanone oxime in 20g of anhydrous acetone and slowly add it dropwise to the IPDI solution from Step 1, controlling the addition time to 1.5h and maintaining the reaction temperature at 0~5℃;

[0094] Step 3: After the addition is complete, continue stirring the reaction at 0~5℃ for 5 hours;

[0095] Step 4: Monitor the -NCO characteristic peak (~2270 cm⁻¹) in the reaction system using Fourier transform infrared spectroscopy (FT-IR). -1 The intensity change of the peak was observed, and the reaction was stopped when the peak intensity dropped to 45%~55% of the initial value. The solvent was removed by vacuum distillation to obtain the single-terminated IPDI intermediate.

[0096] Step 5: Dissolve 8.0g of allyl glycidyl ether in 50g of anhydrous tetrahydrofuran (THF) and stir under nitrogen protection;

[0097] Step 6: Dissolve 6.7g of single-terminated IPDI intermediate in 20g of anhydrous THF, and slowly add it dropwise to the solution in Step 5, controlling the dropwise addition time to 2h, and maintaining the system temperature at 30℃;

[0098] Step 7: After the addition is complete, continue stirring the reaction at 30℃ for 24 hours;

[0099] Step 8: After the reaction is complete, tetrahydrofuran is removed by vacuum distillation to obtain a pale yellow to amber paste or viscous liquid, which is the latent isocyanate functional monomer.

[0100] Application Cases

[0101] Impregnation method

[0102] Fixing agent dosage: 3% (owf)

[0103] Bath ratio: 1:30

[0104] Temperature & Time: 40-50℃ × 15-20min

[0105] Dyed fabric → Immerse in working solution at 40-50℃ for 15-20 minutes → Wash with water → Dry

[0106] Place the bright red fabric into a high-temperature dyeing machine, add the corresponding color-fixing agent and water, heat to 40-50℃ and run for 15-20 minutes, then take it out, wash and dry it, and finally test the finished product.

[0107] The test results can be found in Tables 2 and 3.

[0108] Table 2 Test Results (Reactive Dye Scarlet)

[0109] project blank Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 wet friction fastness Level 2 Level 4 Level 3-3.5 Level 4-4.5 Level 3.5 Level 2.5 Level 3 Level 3 Level 2-2.5 Level 4 Level 3-3.5 Soap wash fastness (color change) Level 3 Level 4.5 Level 4.5 Level 4.5 Level 4 Level 4 Level 4 Level 3.5 Level 4-4.5 Level 3 Level 4.0 Perspiration fastness (color change) Level 4 Level 4.5 Level 4.5 Level 4.5 Level 4 Level 4 Level 4 Level 4 Level 4.5 Level 3 Level 4.0 feel — 4 4.3 3.5 4.5 4.5 3 3.8 4.2 2 4.2 hydrophilic — 4-5 seconds 3-4 seconds 8-10 seconds 2-3 seconds 2-3 seconds >15 seconds 5-6 seconds 2-3 seconds >30 seconds 3-4 seconds

[0110] Table 3 Test Results (Active Turquoise Blue)

[0111] project blank Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 wet friction fastness Level 1.5 Level 3.5 Level 3-3.5 Level 3.5-4 Level 2.5-3 Level 2 Level 2.5 Level 2.5 Level 2 Level 3 Level 2.5-3 Soap wash fastness (color change) Level 2.5 Level 4-4.5 Level 4 Level 4-4.5 Level 3.5-4 Level 3.5 Level 3.5 Level 3 Level 4 Level 3 Level 3.5-4 Perspiration fastness (color change) Level 3 Level 4-4.5 Level 4 Level 4-4.5 Level 4 Level 4 Level 4 Level 3.5 Level 4.5 Level 3 Level 4 feel — 4.1 4.4 3.7 4.6 4.6 3.2 4 4.3 1.8 4.3 hydrophilic — 3-4 seconds 2-3 seconds 6-8 seconds 2-3 seconds 2-3 seconds >15 seconds 4-5 seconds 2-3 seconds >30 seconds 3-4 seconds

[0112] Results analysis:

[0113] A comparison of Examples 1-4 with Comparative Example 1 shows that the introduction of TLI monomer is key to the breakthrough improvement in wet rubbing fastness. Comparative Example 1 (pure cationic system) without TLI showed limited improvement in wet rubbing fastness, while all examples containing TLI monomer exhibited significant improvements. This indicates that the covalent cross-linking network formed by the latent isocyanate groups in the TLI monomer during baking fundamentally enhances the bonding strength between the dye and the fiber.

[0114] A comparison of Examples 1, 2, and 3 shows that there is an optimal range for the amount of TLI monomer. As the TLI amount increased from 15 parts (Example 2) to 20 parts (Example 1), the wet rubbing fastness reached its peak (Red 4.0). Further increasing to 30 parts (Example 3), although the wet rubbing fastness remained extremely high, the feel began to harden (score 3.5), and the hydrophilicity decreased (8-10 seconds). This is because the excessively high crosslinking density led to a decrease in film elasticity and an overly dense network. Example 4 (10 parts TLI) showed a slight decrease in wet rubbing performance due to insufficient crosslinking points. This demonstrates the balance of the formulation design in this invention.

[0115] The negative effects of Comparative Example 2 (TLI excess) and Comparative Example 3 (diallylamine excess) demonstrate the crucial importance of the component ratios. Excess TLI (Comparative Example 2) leads to increased viscosity, poorer film-forming properties, and decreased overall performance of the polymerization system; excess diallylamine (Comparative Example 3) may cause an imbalance in the cationic charge distribution of the polymer and self-crosslinking, which is also detrimental to performance optimization. Comparative Example 6 shows that the triazine functional group has the most significant impact on wet rubbing fastness, while also affecting other fastness properties. This is because the triazine ring forms strong hydrogen bonds and van der Waals forces with the dye sulfonic acid / amino groups; simultaneously, the absence of the triazine functional group slightly increases hydrophilicity.

[0116] Compared to Comparative Example 4 (commercially available formaldehyde-free fixing agent), all embodiments of the present invention exhibit an overwhelming advantage in the core indicator of wet rubbing fastness. Compared to Comparative Example 5 (commercially available polyurethane), the present invention achieves equal or even better wet rubbing fastness while completely avoiding the common industry problems of polyurethane products, such as stiff feel (score 2.0) and complete loss of hydrophilicity (>30 seconds). Examples 1 and 2, while achieving a wet rubbing fastness of grade 4, still maintain a soft feel of 4.0 or higher and acceptable hydrophilicity.

[0117] in conclusion:

[0118] The systematic test data in Tables 2 and 3 demonstrate that this invention, by introducing an innovative TLI monomer and optimizing its ratio with DMDAAC and diallylamine, successfully constructed a multi-synergistic color-fixing system of "electrostatic rapid adsorption + triazine ring anchoring + covalent cross-linking locking." This system not only solves the fundamental problem of weak action of traditional formaldehyde-free color-fixing agents at the molecular level, achieving a breakthrough in wet rubbing fastness of sensitive colors (≥3.5 grade), but also achieves an excellent balance between ultra-high performance and fabric performance (hand feel, hydrophilicity) through ingenious molecular structure design, possessing significant competitive advantages in industrialization.

[0119] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer, characterized in that, It is prepared by free radical polymerization from triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine. The mass ratio of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 10~30:30~48:

10.

2. The formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer according to claim 1, characterized in that, The triazine-latent isocyanate functional monomer is synthesized through the following steps: Step 1: In a polar aprotic solvent, under nitrogen protection and in the presence of a polymerization inhibitor, melamine is reacted with an excess of allyl glycidyl ether at 110-130°C for 6-12 hours to generate intermediate A containing a triazine core, multiple hydroxyl groups and multiple allyl double bonds. Step 2: At 0~10℃, under anhydrous and inert atmosphere, isophorone diisocyanate is reacted with an equimolar amount of the capping agent butanone oxime to selectively cap the primary isocyanate group of isophorone diisocyanate, to obtain intermediate B of single-capped IPDI retaining a secondary isocyanate group. Step 3: In an inert solvent, intermediate A and intermediate B are reacted at 30-60°C for 12-24 hours. The secondary isocyanate group of intermediate B is linked to some of the secondary amine or hydroxyl groups on intermediate A to finally obtain the triazine-latent isocyanate functional monomer.

3. The formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer according to claim 1, characterized in that, The fixing agent is a water-soluble or water-dispersible polymer obtained by free radical copolymerization, with a weight-average molecular weight of 50,000 to 300,000 g / mol.

4. The formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer according to claim 2, characterized in that, The inert solvent is one or more combinations of anhydrous tetrahydrofuran, anhydrous acetone, and anhydrous acetonitrile; the weight ratio of the inert solvent to the total weight of intermediate A and intermediate B is 200~300:

100.

5. The formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer according to claim 2, characterized in that, The molar ratio of intermediate A to intermediate B is 0.9~1.1:0.9~1.

1.

6. A method for preparing a formaldehyde-free fixing agent based on a triazine-latent isocyanate functional monomer as described in any one of claims 1 to 5, characterized in that, Includes the following steps: Step 1: Dissolve the triazine-latent isocyanate functional monomer in deionized water, heat to 70~80℃, and protect with nitrogen. Step 2: Add dropwise an aqueous solution of a mixed monomer of dimethyl diallyl ammonium chloride and diallylamine, while simultaneously adding an aqueous solution of a water-soluble initiator, controlling the total adding time to 2-4 hours; Step 3: After the addition is complete, keep the temperature at 70~80℃ for 1~3 hours to allow the reaction to proceed; Step 4: Cool down to below 40℃, adjust pH to 5.0~7.0, discharge the material, and obtain the product.

7. The preparation method according to claim 6, characterized in that, The ratio of the total weight of deionized water in steps 1 and 2 to the total weight of triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine is 150-250:

100.

8. The preparation method according to claim 6, characterized in that, The initiator is one of ammonium persulfate, potassium persulfate, or azobisisobutyramidine hydrochloride; the amount of the initiator is equivalent to 1 to 3 wt% of the total weight of the triazine-latent isocyanate functional monomer, dimethyl diallyl ammonium chloride, and diallylamine.