A waterless digital dyeing adhesive with a function of unidirectional loading of disperse dyes and a preparation method thereof

Abstract

The application provides a water-free digital dyeing adhesive with a one-way dispersion dye carrying function and a preparation method thereof; the adhesive is prepared by using dibutyl tin dilaurate as a catalyst, isophorone diisocyanate, poly-1,4-butanediol adipate, hydroxyl-terminated polyoxysilane, 2,2-dimethylol butyric acid and 1,4-butanediol in sequence for polycondensation and chain extension reaction, then adding 2-butanone oxime for end capping, and finally performing neutralization to obtain a silicone-modified waterborne polyurethane emulsion. The adhesive is applied to digital jet dyeing of polyester fabric with dispersion dyes, and not only can the reduction cleaning and water washing processes be omitted, but also the color yield of the dyed fabric is increased by 14-20% than that of pure dye ink jet dyeing, the dry rubbing fastness is increased by 2 grades, the wet rubbing fastness is increased to 1 grade, and the adhesive has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of dyeing and printing auxiliaries technology, specifically relating to a waterless digital dyeing adhesive with unidirectional dispersible dye delivery function and its preparation method. Background Technology

[0002] Polyester fabrics are commonly colored with disperse dyes, and the conventional dyeing methods are mainly immersion dyeing and pad dyeing. After dyeing, reduction washing and multiple washing processes are required to remove surface dye, which generates a large amount of dyeing wastewater, placing a serious burden on the environment. Digitalization and greening are the themes of future development in the textile printing and dyeing industry. Disperse dye waterless digital spraying combines digital spraying technology with disperse dye waterless printing and dyeing technology, offering advantages such as simple process, emission reduction and carbon reduction, dye and chemical saving, and personalized and rapid response. It represents a breakthrough in clean dyeing technology for polyester fabrics. This technology will drive the digital transformation and upgrading of the printing and dyeing industry and its sustainable development.

[0003] Disperse dyes have similar solubility parameters to polyester fibers and exhibit an affinity for the fibers; their dyeing process can be viewed as the formation of a "solid solution." When the dyeing temperature is higher than the glass transition temperature of polyester, the dye on the fiber surface diffuses in molecular form and dissolves in the pores of the amorphous regions of the polyester fiber, adsorbing and fixing with the fiber through interactions such as hydrogen bonds, van der Waals forces, and hydrophobic bonds. Based on this, utilizing the thermal sublimation of disperse dyes and the film-forming properties of polymeric adhesives, and taking advantage of the solubility difference between disperse dyes and the polymeric film, during high-temperature baking, a large amount of dye migrates, diffuses, and fixes towards the polyester fabric; a small amount of dye dissolves and fixes within the polymeric film. With the synergy of both, subsequent reduction washing and rinsing processes can be eliminated, achieving a waterless dyeing effect. Currently, there are reports in China regarding waterless dyeing and printing of polyester fabrics. Patent document CN107988822A discloses "A High Dye-Carrying Adhesive for Disperse Dye Wash-Free Printing and Its Preparation Method," providing a method for preparing an organosilicon-modified acrylate adhesive with high dye-carrying capacity. This adhesive can improve the color yield and rubbing fastness of printed fabrics. Patent document CN107988822A also discloses "A Fluorosilicone-Modified Polyacrylate Adhesive and Its Preparation Method," providing a method for preparing a fluorosilicone-modified polyacrylate adhesive for hot-melt dyeing of polyester liquid disperse dyes. This adhesive can prevent migration and also achieve good color yield and fastness.

[0004] However, conventional waterless adhesive films dissolve and retain some disperse dyes. During use, dyes on undyed fibers can migrate and diffuse to the film surface due to external environmental factors (light, heat, friction, etc.), resulting in poor colorfastness of the printed fabric. Therefore, increasing the difference in solubility parameters between disperse dyes and polymers, so that the dyes migrate and diffuse unidirectionally towards the fabric as much as possible, and migrate to the film surface or remain in the film as little as possible, is the key to achieving good waterless dyeing results for polyester.

[0005] Currently, most existing polyester no-wash adhesives are modified acrylates, which suffer from problems such as unsatisfactory color fastness to rubbing. Compared with polyacrylates, waterborne polyurethanes connect soft and hard segments through hydrogen bonds, resulting in more hydrogen bonding interactions within the waterborne polyurethane segments and thus better adhesive properties. The molecular structure of polyester no-wash adhesives is designed based on the difference in solubility parameters between the adhesive and disperse dyes. Monomers need to be optimized based on solubility parameter principles to achieve high unidirectional dye delivery in the synthesized waterborne polyurethane. Therefore, to improve the surface color gain of polyester no-wash spray-dyed fabrics while maintaining good color fastness, there is an urgent need to develop high-performance modified waterborne polyurethane adhesives. Summary of the Invention

[0006] The current problem with waterless spray dyeing technology for disperse dyes is that some dye remains within the adhesive film, resulting in poor color gain and color fastness on the surface of the sprayed fabric. To achieve waterless digital spray dyeing of polyester, based on the migration mechanism of dyes in the adhesive film, monomers with significantly different solubility parameters from disperse dyes are selected when synthesizing waterborne polyurethane. This widens the solubility difference between the disperse dye and the adhesive, achieving unidirectional transport of the disperse dye and promoting more disperse dye to the fabric. Simultaneously, utilizing the excellent bonding properties of waterborne polyurethane, the adhesive film on the fabric surface can withstand strong external mechanical forces, thereby improving the rubbing fastness of the waterless polyester fabric.

[0007] First, based on the solubility parameters, rigid polyester glycol poly(1,4-butanediol adipate) with strong cohesive energy and excellent bonding properties is selected as the soft segment, 1,4-butanediol as the chain extender, and 2,2-dimethylolbutyric acid as the hydrophilic monomer.

[0008] Secondly, the wet rubbing fastness of waterless spray-dyed fabrics mainly depends on the low coefficient of friction, water resistance, mechanical properties, and adhesion properties of the fabric after the polymer emulsion film is formed. To improve the low coefficient of friction and softness of the coating film, polydimethylsiloxane, which has a significantly different solubility parameter from disperse dyes, is introduced into waterborne polyurethane as a soft segment. This further expands the difference in solubility parameters, resulting in waterless spray-dyed fabrics with high color yield. At the same time, the high-temperature phase separation characteristics, good hydrophobicity, and smoothness of the organosilicon segments are used to improve the color fastness of the spray-dyed fabrics.

[0009] Finally, to further obtain better adhesion performance, 2-butanone oxime was used as a sealing agent. This sealing agent will deseal during high-temperature baking, releasing active isocyanate groups, which can crosslink with polyester fabrics to improve the adhesion strength of the adhesive film and improve the color fastness of spray-dyed fabrics to a certain extent.

[0010] Based on the above analysis, this invention provides a waterless digital dyeing adhesive with unidirectional disperse dye delivery function and its preparation method. This organosilicon-modified waterborne polyurethane, when applied to digital dyeing of polyester fabrics, eliminates the need for reduction washing and water washing processes. Furthermore, the dyed fabrics exhibit high surface color yield and excellent dry / wet rubbing fastness, demonstrating broad application prospects.

[0011] A waterless digital dyeing adhesive with unidirectional disperse dye delivery function, the structure of which is as follows:

[0012]

[0013] Among them, R1 comes from poly(1,4-butanediol adipate) (PBA), R2 comes from hydroxyl-terminated polyoxysilane (PDMS), R3 comes from 2,2-dimethylolbutyric acid, and R4 comes from 1,4-butanediol (BDO).

[0014] A waterless digital dyeing adhesive with unidirectional dispersive dye delivery function is obtained by polymerization of R1 derived from poly(1,4-butanediol adipate) (PBA), R2 derived from hydroxyl-terminated polyoxysilane (PDMS), R3 derived from 2,2-dimethylolbutyric acid, and R4 derived from 1,4-butanediol (BDO) as monomers.

[0015] A waterless digital dyeing adhesive with unidirectional dispersive dye delivery function is prepared by any of the following methods.

[0016] This invention also provides a method for preparing the above-mentioned waterless digital dyeing adhesive with unidirectional disperse dye delivery function, comprising: poly(1,4-butanediol adipate), hydroxyl-terminated polyoxysilane, and a corresponding amount of isophorone diisocyanate undergoing a polycondensation reaction under the action of a catalyst to obtain an organosilicon-modified waterborne polyurethane prepolymer P1; 2,2-dimethylolbutyric acid is added, and polycondensation reaction is continued with P1 and a corresponding amount of isophorone diisocyanate to obtain an organosilicon-modified waterborne polyurethane prepolymer P2; then 1,4-butanediol is added, and chain extension reaction is carried out with P2 and a corresponding amount of isophorone diisocyanate; finally, 2-butanone oxime is used for end-capping; post-treatment yields the waterless digital dyeing adhesive with unidirectional disperse dye delivery function.

[0017] In this invention, all reactive monomers include isophorone diisocyanate (IPDI), poly(1,4-butanediol adipate) (PBA), hydroxyl-terminated polyoxysilane (PDMS), 2,2-dimethylolbutyric acid (DBA), and 1,4-butanediol (BDO).

[0018] Furthermore, the molar ratio of isocyanate groups to total active hydroxyl groups in the reactant monomers, i.e., the chain extension coefficient R, is (1.0~1.7):1. Among them, the monomer containing isocyanate groups is IPDI, and the monomers containing hydroxyl groups include PBA, PDMS, DBA, and BDO.

[0019] Furthermore, the synthesized monomers consist of hard monomers and soft segments, with a defined proportion of hard monomers, i.e., the hard segment content (H) accounts for 34-46% of the monomer mass. Among them, the hard monomers include IPDI, DBA, and BDO, and the soft segments are PBA and PDMS.

[0020] Furthermore, the isophorone diisocyanate accounts for 25-36% of the total monomer mass, poly(1,4-butanediol adipate) accounts for 48-62% of the total monomer mass, hydroxyl-terminated polyoxysilane accounts for 2-11% of the total monomer mass, 2,2-dimethylolbutyric acid accounts for 4-6% of the total monomer mass, 1,4-butanediol accounts for 1.5-6% of the total monomer mass, and the catalyst accounts for 0.02-0.04% of the total monomer mass.

[0021] This invention also provides a method for preparing the above-mentioned waterless digital dyeing adhesive with unidirectional disperse dye delivery function, comprising the following steps:

[0022] (1) First, dry PBA, PDMS and DBA in a vacuum oven.

[0023] (2) Using dibutyltin dilaurate as a catalyst, IPDI, PBA and PDMS were added to a four-necked flask in sequence, under nitrogen protection, and the temperature was raised to carry out a polycondensation reaction to obtain organosilicon-modified waterborne polyurethane prepolymer P1.

[0024] (3) Dissolve DBA in N-methylpyrrolidone, then add it to a four-necked flask and continue the reaction to obtain organosilicon-modified waterborne polyurethane prepolymer P2. During the reaction, observe the viscosity change of the system and add an appropriate amount of acetone to reduce viscosity.

[0025] (4) After initial cooling, add BDO to carry out chain extension reaction.

[0026] (5) Cool down again and add 2-butanone oxime for end capping. Take samples at intervals and monitor with infrared spectroscopy until the characteristic peak of the NCO group completely disappears.

[0027] (6) Finally, cool down, add triethylamine for neutralization, then add deionized water for high-speed emulsification, and rotary evaporate to obtain organosilicon modified waterborne polyurethane emulsion.

[0028] Preferably, in step (1), the temperature of the vacuum oven is 70-90℃ and the drying time is 1-3h.

[0029] Preferably, in step (2), the molar ratio of isocyanate groups to total active hydroxyl groups is (1.0~1.7):1, more preferably 1.33~1.36:1; more specifically 1.34~1.35:1; and more specifically 1.34:1 or 1.35:1.

[0030] As a preferred option, in step (2):

[0031] IPDI comprises 29-36% of the total mass of the raw materials used in the preparation; more preferably 30-36%; even more specifically, 32-34%; and still more preferably 32-33%. More preferably, IPDI comprises 32%, 32.5%, and 33% of the total mass of the monomers.

[0032] The mass of PBA accounts for 48-58% of the total mass of the monomers; more preferably 48-55%; more specifically preferably 50-55%; and even more preferably 51-53%. As a specific preferred option, the mass of PBA accounts for 52-53% of the total mass of the raw materials used in preparation; more preferably 52%, 52.5%, or 53%.

[0033] The mass of PDMS accounts for 2-10% of the total mass of the monomers; more preferably 4-8%; and even more specifically 5-7%. Further, the mass of PDMS accounts for 6% or 6.1% of the total mass of the monomers.

[0034] Preferably, in step (2), the mass of dibutyltin dilaurate accounts for 0.02~0.04% of the total mass of the monomers. More preferably, it is 0.03%.

[0035] Preferably, in step (2), the heating temperature is 75~85℃ and the reaction time is 1~3h.

[0036] Preferably, in step (3), DBA accounts for 4-6% of the total mass of the monomers, and N-methylpyrrolidone accounts for 200-220% of the mass of DBA. Alternatively, DBA accounts for 5% of the total mass of the monomers, and N-methylpyrrolidone accounts for 210% of the mass of DBA.

[0037] Preferably, in step (3), the reaction temperature is 75~85℃ and the reaction time is 1~3h.

[0038] As a preferred option, in step (4), the reaction system is cooled to 65~75℃ and the chain extension reaction time is 1~2h.

[0039] Preferably, in step (4), BDO accounts for 2-6% of the total mass of the monomer. More preferably, it is 3-4%; even more preferably, it is 3.5-4%; specifically, it can be 3.8%, 3.9%, or 4%.

[0040] Preferably, in step (5), the amount of 2-butanone oxime added is calculated based on the molar ratio of isocyanate groups to total active hydroxyl groups (1.0~1.7):1, using the remaining molar number of unreacted isocyanate groups. More preferably, when the molar ratio of isocyanate groups to total active hydroxyl groups is 1.35:1, the amount of 2-butanone oxime added accounts for 8% of the total mass of the monomer.

[0041] Preferably, in step (5), the end-capping reaction temperature is 55~65℃ and the end-capping time is 2~4h.

[0042] Preferably, in step (6), triethylamine accounts for 4-6% of the total mass of the monomers, and the amount of deionized water added accounts for 186-300% of the total mass of the monomers. More preferably, triethylamine accounts for 5% of the total mass of the monomers, and the amount of deionized water added accounts for 243% of the total mass of the monomers.

[0043] Preferably, in step (6), the rotation speed during emulsification is 750~850 rpm and the emulsification time is 0.5~1.5 h.

[0044] Preferably, in step (6), the rotary evaporation temperature is 35~45℃ and the rotary evaporation time is 0.5~1.5h.

[0045] Preferably, the molecular weight of PBA is 1500-3000, and the molecular weight of PDMS is 500-1500. More preferably, the molecular weight of PBA is 2000, and the molecular weight of PDMS is 1000.

[0046] Furthermore, the R-value, PDMS content, and hard segment content (H) are calculated as follows:

[0047] ;

[0048] ;

[0049] .

[0050] The preparation method of this invention preferably involves synthesizing waterborne polyurethane monomers and modifying the waterborne polyurethane using polysiloxane segments to prepare an organosilicon-modified waterborne polyurethane adhesive with unidirectional disperse dye delivery function. The adhesive prepared by this invention, when used in waterless digital spray dyeing of polyester fabrics with disperse dyes, not only eliminates the need for reduction cleaning and washing processes, but also results in higher surface color yield and color fastness of the dyed fabrics, demonstrating broad application prospects.

[0051] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0052] This invention leverages the difference in solubility parameters between waterborne polyurethane monomers and disperse dyes, preferentially synthesizing waterborne polyurethane using the preferred monomers to amplify this solubility parameter difference. Furthermore, it utilizes polysiloxane modification of the waterborne polyurethane to further expand this difference. On one hand, the difference in solubility parameters promotes the migration, diffusion, and fixation of disperse dyes onto the fabric surface and into the fiber interior, increasing the color yield of waterless polyester fabrics. On the other hand, the excellent bonding properties of waterborne polyurethane itself, along with the high-temperature phase separation characteristics, hydrophobicity, and slip properties of silicone, improve the rubbing fastness of waterless polyester fabrics. Compared to polyester fabrics dyed with pure disperse dye ink, the surface color yield of polyester fabrics dyed with silicone-modified waterborne polyurethane is increased by 14-20%, dry rubbing fastness is improved by 2 grades, and wet rubbing fastness is improved by 1 grade.

[0053] Waterborne polyurethane connects soft and hard segments through hydrogen bonds, resulting in numerous hydrogen bonds within the segments and thus superior adhesion. In the selection of soft segments, this invention chose rigid polyester glycol, which has a significantly different solubility parameter from disperse dyes and exhibits better adhesion, to achieve better colorfastness. Simultaneously, by adjusting the ratio of soft to hard segments and the chain extension coefficient, the number of hydrogen bonds formed is controlled, ensuring good adhesion between the waterborne polyurethane and polyester fabrics. Compared to polyester fabrics dyed with pure dye inks, increasing the color yield of the dyed fabric improves the dry rubbing colorfastness from grade 3-4 to grade 4-5.

[0054] Polyoxysilane segments, as soft segments, are incorporated into the main chain of waterborne polyurethane. During high-temperature baking, these low-surface-energy organosilicon segments migrate to the film surface, forming a silica layer. This improves the smoothness of the film, reduces hydrophilicity, and prevents dye migration and diffusion beyond the film, all of which contribute to improving the color fastness of polyester no-wash spray-dyed fabrics. Compared to fabrics sprayed with pure dye inks, the wet rubbing color fastness of no-wash adhesive-sprayed fabrics improves from grade 3 to grade 3-4. Polyoxysilanes have a lower solubility parameter, which can further amplify the difference in solubility parameters, promoting more dye migration into the fabric. Simultaneously, organosilicon has a lower refractive index, resulting in an optical deepening effect after film formation, further enhancing the surface color gain.

[0055] In summary, the organosilicon-modified waterborne polyurethane prepared by this invention can be used in waterless digital dyeing of polyester, which not only eliminates the need for reduction cleaning and water washing processes, but also results in high surface color gain and rubbing fastness of the dyed fabric, and has broad application prospects. Attached Figure Description

[0056] Figure 1 The infrared spectra of the silicone-modified waterborne polyurethane films prepared in Example 1 with silicone dosages of 0.4g, 1.2g, and 2g, and the silicone-free waterborne polyurethane film are shown.

[0057] Figure 2 This is a schematic diagram illustrating the steps involved in preparing a waterless digital dyeing adhesive with unidirectional disperse dye delivery function, as shown in the examples. Detailed Implementation

[0058] The technical solution of the present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are only for illustrating the technical solution of the present invention and are not intended to limit the scope of the present invention. After reading the teachings of this invention, those skilled in the art can make various modifications or alterations to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0059] In this embodiment, the abbreviations for the raw materials used are as follows:

[0060]

[0061] Examples 1-1 to 1-3: Changing the amount of hydroxyl-terminated polysiloxane

[0062] In Examples 1-1 to 1-3: the R value is between 1.34 and 1.35; the hard segment content is between 41 and 42 wt%.

[0063] Example 1-1:

[0064] (1) The total amount of monomer input was 19.87g, and the amount of PBA and PDMS input was 11.6g. First, PBA with a molecular weight of 2000 (11.2g), PDMS with a molecular weight of 1000 (0.4g), and DBA (1g) were dried in a vacuum oven at 90℃ for 2h. (2) Using 0.006g of dibutyltin dilaurate as a catalyst, 6.47g of IPDI, a total amount of PBA and PDMS (11.6g) were added to a four-necked flask in sequence. Under nitrogen protection, the temperature was raised to 80℃ and polycondensation reaction was carried out for 2h to obtain organosilicon modified waterborne polyurethane prepolymer P1.

[0065] (3) Dissolve 1g of DBA in 2.1g of N-methylpyrrolidone, then add the solution to the four-necked flask from step (2), and continue the reaction at 80℃ for 2h to obtain organosilicon-modified waterborne polyurethane prepolymer P2. During the reaction, observe the viscosity change of the system, and add an appropriate amount of acetone to reduce viscosity.

[0066] (4) Cool down to 70°C for the first time, add BDO (0.80g), and carry out chain extension reaction for 1.5h.

[0067] (5) Cool down to 60℃ again, add 1.57g of 2-butanone oxime and carry out the end-capping reaction for 2h. Take samples at intervals and monitor with infrared spectroscopy until the characteristic peak of the NCO group completely disappears.

[0068] (6) Finally, the temperature was lowered to 40°C, 0.68g of triethylamine was added for neutralization, followed by 49g of deionized water. The mixture was emulsified at 800rpm for 1 hour and then rotary evaporated at 40°C to obtain the organosilicon-modified waterborne polyurethane emulsion.

[0069] The preparation methods for Examples 1-2 and 1-3 are the same as those for Example 1-1, and the amounts of materials added are shown in the table below:

[0070]

[0071]

[0072] Three types of silicone-modified waterborne polyurethane adhesive products were obtained from Examples 1-1 to 1-3.

[0073] The above-mentioned organosilicon-modified waterborne polyurethane adhesive and liquid disperse dye were used to formulate a dye ink for digital spraying of polyester fabrics.

[0074] Dye solution formulation: 3wt% Liquid Dispersible Red CI 167, 8wt% binder emulsion, 89wt% deionized water, total 100wt%.

[0075] Dyeing process: Polyester fabric → spray dyeing → drying (80℃, 2min) → high temperature baking (190℃, 3min) → finished product.

[0076] Under the above conditions, organosilicon-modified waterborne polyurethane adhesives prepared with different amounts of hydroxyl-terminated polysiloxane were used for waterless digital spray dyeing of polyester fabrics. The effects of the amount of hydroxyl-terminated polyoxysilane on the color yield (K / S), penetration rate and rubbing fastness of the dyed fabric surface were investigated. The results are shown in Table 1.

[0077] Table 1. Effect of hydroxyl-terminated polyoxysilane dosage on the waterless digital dyeing performance of polyester fabrics.

[0078]

[0079] As shown in Table 1, with the increase of hydroxyl-terminated polysiloxane dosage, the color gain of polyester digitally spray-dyed fabrics gradually increased and then leveled off. Dry rubbing fastness remained constant, while wet rubbing fastness initially increased and then decreased. When the dosage of hydroxyl-terminated polysiloxane was 1.2g, the color gain on the front and back sides of the fabric reached 16.25g and 13.3g respectively, with dry rubbing fastness reaching grade 4-5 and wet rubbing fastness reaching grade 3-4. Further increasing the dosage of organosilicon segments did not significantly change the color gain, but the wet rubbing fastness actually decreased.

[0080] Silicone-modified waterborne polyurethane films with silicone content of 0.4g, 1.2g, and 2g, as well as a silicone-free waterborne polyurethane film, were obtained by forming the emulsion at room temperature, drying at 80℃ for 2 min, and baking at 190℃ for 3 min, respectively. The infrared spectra of the different films are shown below. Figure 1 As shown, WPU is a waterborne polyurethane film formed without the introduction of silicone modification. Si-0.4 WPU Si-1.2 WPU Si-2 The films were formed from silicone-modified waterborne polyurethane with PDMS dosages of 0.4g, 1.2g, and 2g, respectively. Figure 1 Middle, 3352 cm -1 It is the tensile vibration peak of NH, 2956~2873 cm. -1 These are characteristic peaks of -CH3 and -CH2, located in the range of 2280–2200 cm⁻¹. -1 The absence of a characteristic peak at 1726 cm⁻¹ indicates that all N=C=O groups have reacted. -1 The characteristic absorption peak at 1524 cm⁻¹ is an overlap of the carbonyl groups of urethane and acrylate. -1 The peak of the bending vibration of NH is at 1168 cm⁻¹. -1 The peak at 1257 cm⁻¹ is the characteristic absorption peak of OCO. -1 1022 cm-1 and 801 cm -1 The values ​​represent the characteristic absorption peaks of the -CH3 deformation vibration, Si-O-Si bond, and Si-C bond in polysiloxane Si-CH3, respectively. It can be seen that the intensity of the related peaks of polysiloxane increases with the increase of organosilicon segment content.

[0081] Example 2: Changing the chain extension coefficient (molar ratio of isocyanate groups to total active hydroxyl groups)

[0082] In Examples 2-1 to 2-3, the fixed hard segment content was between 41 and 42 wt%; the PDMS content was 6 wt%; and the R values ​​were 1.05, 1.34, and 1.64, respectively.

[0083] (1) The total amount of monomer input is 19.80g, and then the amount of soft segment is determined. First, 10.4g of PBA, 1.2g of PDMS and 1g of DBA are dried in a vacuum oven at 90℃ for 2h.

[0084] (2) Using 0.006 g of dibutyltin dilaurate as a catalyst, IPDI (6.05 g), PBA and PDMS totaling 11.6 g were added sequentially to a four-necked flask under nitrogen protection and the temperature was raised to 80 °C for 2 h to carry out polycondensation reaction to obtain organosilicon modified waterborne polyurethane prepolymer P1.

[0085] (3) Dissolve 1g of DBA in 2.1g of N-methylpyrrolidone solution, then add the solution to a four-necked flask and continue the reaction for 2 hours to obtain organosilicon-modified waterborne polyurethane prepolymer P2. During the reaction, observe the viscosity change of the system and add an appropriate amount of acetone to reduce viscosity.

[0086] (4) Cool down to 70°C for the first time, add BDO (1.15g), and carry out chain extension reaction for 1.5h.

[0087] (5) Cool down to 60°C again, add 0.27 g of 2-butanone oxime and carry out the end-capping reaction for 2 h. Take samples at intervals and monitor with infrared spectroscopy until the characteristic peak of the NCO group completely disappears.

[0088] (6) Finally, the temperature was lowered to 40°C, 0.68g of triethylamine was added for neutralization, followed by 49g of deionized water. The mixture was emulsified at 800rpm for 1 hour and then rotary evaporated at 40°C to obtain the organosilicon-modified waterborne polyurethane emulsion.

[0089] The preparation methods for Examples 2-2 and 2-3 are the same as those for Example 2-1, and the amounts of materials added are shown in the table below:

[0090]

[0091] Three types of organosilicon-modified waterborne polyurethane adhesive products were obtained from Examples 2-1 to 2-3.

[0092] The above-mentioned organosilicon-modified waterborne polyurethane adhesive and liquid disperse dye were used to formulate a dye ink for digital spraying of polyester fabrics.

[0093] Dye solution formulation: 3wt% Liquid Dispersible Red CI 167, 8wt% binder emulsion, 89wt% deionized water, total 100wt%.

[0094] Dyeing process: Polyester fabric → spray dyeing → drying (80℃, 2min) → high temperature baking (190℃, 3min) → finished product.

[0095] Under the above conditions, organosilicon-modified waterborne polyurethane adhesives prepared with different amounts of hydroxyl-terminated polysiloxanes were used for waterless digital spray dyeing of polyester fabrics. The effects of the amount of organosilicon segments on the color yield (K / S), penetration rate and rubbing fastness of the dyed fabric surface were investigated. The results are shown in Table 2.

[0096] Table 2. Effect of chain extension coefficient on the waterless digital dyeing performance of polyester fabrics

[0097]

[0098] As shown in Table 2, with the increase of the chain extension coefficient R, the color gain on the front side of the spray-dyed fabric slightly increases, while the color gain on the back side slightly decreases, reflecting a slight decrease in dye penetration. The color fastness to dry rubbing and wet rubbing first increases and then remains constant. When the chain extension coefficient is 1.34, the color gain of the spray-dyed fabric is good, and there is no significant difference in color gain between the front and back sides. The K / S values ​​are 16.25 and 13.3, respectively, and the color fastness to dry and wet rubbing reaches grades 4-5 and 3-4, respectively.

[0099] Examples 3-1 to 3-4: Changing the proportion of hard segments

[0100] In Examples 3-1 to 3-4, the R value was approximately 1.35 (1.34 in Example 3-3, and 1.35 in the others); the PDMS content was 6%; and the mass percentages of the hardened segments were 0.33, 0.37, 0.42, and 0.46, respectively.

[0101] (1) The total amount of monomer input is 19.80g. First, PBA (12g), PDMS (1.2g) and DBA (1g) are dried in a vacuum oven at 90℃ for 2h.

[0102] (2) Using 0.006 g of dibutyltin dilaurate as a catalyst, IPDI (5.27 g), total amounts of PBA and PDMS of 13.2 g, 12.4 g, 11.6 g and 10.8 g respectively were added to a four-necked flask, under nitrogen protection, and the temperature was raised to 80 °C for 2 h to carry out polycondensation reaction to obtain organosilicon modified waterborne polyurethane prepolymer P1.

[0103] (3) Dissolve 1g of DBA in 2.1g of N-methylpyrrolidone solution, then add the solution to a four-necked flask and continue the reaction for 2 hours to obtain organosilicon-modified waterborne polyurethane prepolymer P2. During the reaction, observe the viscosity change of the system and add an appropriate amount of acetone to reduce viscosity.

[0104] (4) Cool down to 70°C for the first time, add BDO (0.33g), and carry out chain extension reaction for 1.5h.

[0105] (5) Cool down to 60°C again, add 1.28 g of 2-butanone oxime and carry out the end-capping reaction for 2 h. Take samples at intervals and monitor with infrared spectroscopy until the characteristic peak of the NCO group completely disappears.

[0106] (6) Finally, the temperature was lowered to 40°C, 0.68g of triethylamine was added for neutralization, followed by 49g of deionized water. The mixture was emulsified at 800rpm for 1 hour and then rotary evaporated at 40°C to obtain the organosilicon-modified waterborne polyurethane emulsion.

[0107] The above-mentioned organosilicon-modified waterborne polyurethane adhesive and liquid disperse dye were used to formulate a dye ink for digital spraying of polyester fabrics.

[0108] The preparation methods for Examples 3-2 to 3-4 are the same as those for Example 3-1, and the amounts of materials added are shown in the table below:

[0109]

[0110]

[0111] Three types of silicone-modified waterborne polyurethane adhesive products were obtained from Examples 3-1 to 3-4.

[0112] Dye solution formulation: 3wt% Liquid Dispersible Red CI 167, 8wt% binder emulsion, 89wt% deionized water, total 100wt%.

[0113] Dyeing process: Polyester fabric → spray dyeing → drying (80℃, 2min) → high temperature baking (190℃, 3min) → finished product.

[0114] Under the above conditions, silicone-modified waterborne polyurethane adhesives prepared with different amounts of hard segments were used for waterless digital spray dyeing of polyester fabrics. The effects of hard segment dosage on the color yield (K / S), penetration rate and rubbing fastness of the dyed fabric surface were investigated. The results are shown in Table 3.

[0115] Table 3. Effect of different amounts of hard chain segments on the waterless digital dyeing performance of polyester fabrics.

[0116]

[0117] As shown in Table 3, with the increase of the amount of hard chain segment, the color gain of the spray-dyed fabric did not change significantly, the dry rubbing fastness remained unchanged, and the wet rubbing fastness improved but remained unchanged. When the amount of hard chain segment was 8.24g, the color gain on the front and back sides of the spray-dyed fabric reached 16.25g and 13.30g, respectively, and the dry and wet rubbing fastness reached grades 4-5 and 3-4, respectively.

[0118] Example 4: Comparison of dyeing performance between homemade adhesive, pure dye, and commercially available adhesive

[0119] (1) First, dry 10.4g of PBA, 1.2g of PDMS and 1g of DBA in a vacuum oven at 90℃ for 2h.

[0120] (2) Using 0.006 g of dibutyltin dilaurate as a catalyst, 6.47 g of IPDI, 11.6 g of PBA and PDMS were added sequentially to a four-necked flask under nitrogen protection and heated to 80 °C for 2 h to obtain organosilicon modified waterborne polyurethane prepolymer P1.

[0121] (3) Dissolve 1g of DBA in 2.1g of N-methylpyrrolidone solution, then add the solution to a four-necked flask and continue the reaction for 2 hours to obtain organosilicon-modified waterborne polyurethane prepolymer P2. During the reaction, observe the viscosity change of the system and add an appropriate amount of acetone to reduce the viscosity.

[0122] (4) Cool down to 70°C for the first time, add 0.77g of BDO, and carry out the chain extension reaction for 1.5h.

[0123] (5) Cool down to 60℃ again, add 1.57g of 2-butanone oxime and carry out the end-capping reaction for 2h. Take samples at intervals and monitor with infrared spectroscopy until the characteristic peak of the NCO group completely disappears.

[0124] (6) Finally, the temperature was lowered to 40°C, 0.68g of triethylamine was added for neutralization, followed by 49g of deionized water. The mixture was emulsified at 800rpm for 1 hour and then rotary evaporated at 40°C to obtain the organosilicon-modified waterborne polyurethane emulsion.

[0125] The above-mentioned organosilicon-modified waterborne polyurethane adhesive and liquid disperse dye were used to formulate a dye ink for digital spraying of polyester fabrics.

[0126] Dye solution formulation: 3wt% Liquid Dispersible Red CI 167, binder emulsion, deionized water, total 100wt%.

[0127] Dyeing process: Polyester fabric → spray dyeing → drying (80℃, 2min) → high temperature baking (190℃, 3min) → finished product.

[0128] Under the above conditions, dye inks with different amounts of self-made silicone-modified waterborne polyurethane adhesive were used for waterless digital inkjet dyeing of polyester fabrics. The results of color gain (K / S), penetration, and rubbing fastness of the dyed fabrics are shown in Table 4.

[0129] Table 4. Effect of silicone-modified waterborne polyurethane dosage on digital dyeing performance of polyester fabrics

[0130]

[0131] As can be seen from Table 4, compared with fabrics dyed with pure dyes, the self-made organosilicon-modified waterborne polyurethane adhesive can significantly increase the color yield of dyed fabrics, improve the dry rubbing color fastness by 2 grades, and improve the wet rubbing color fastness by 1 grade.

Claims

1. The application of a water-based polyurethane adhesive with unidirectional disperse dye delivery function in waterless digital spray dyeing of polyester fabrics, characterized in that, The waterborne polyurethane adhesive with unidirectional disperse dye delivery function is prepared by the following method: poly(1,4-butanediol adipate), hydroxyl-terminated polyoxysilane, and a corresponding amount of isophorone diisocyanate undergo a polycondensation reaction under the action of a catalyst to obtain an organosilicon-modified waterborne polyurethane prepolymer P1; 2,2-dimethylolbutyric acid is added, and the polycondensation reaction with P1 continues to obtain an organosilicon-modified waterborne polyurethane prepolymer P2; then 1,4-butanediol is added, and the chain extension reaction with P2 is carried out; finally, 2-butanone oxime is used for end-capping; post-treatment yields the waterborne polyurethane adhesive with unidirectional disperse dye delivery function. In the synthetic monomers, isophorone diisocyanate, 2,2-dimethylolbutyric acid, and 1,4-butanediol account for 34-46% of the total monomer mass; The isophorone diisocyanate accounts for 25-36% of the total monomer mass, poly(1,4-butanediol adipate) accounts for 48-62% of the total monomer mass, hydroxyl-terminated polyoxysilane accounts for 2-11% of the total monomer mass, 2,2-dimethylolbutyric acid accounts for 4-6% of the total monomer mass, and 1,4-butanediol accounts for 1.5-6% of the total monomer mass. The molar ratio of isocyanate groups to total active hydroxyl groups, i.e. the chain extension coefficient R, is (1.0~1.7):

1.

2. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 1 in waterless digital spray dyeing of polyester fabrics, characterized in that, Includes the following steps: (1) First, dry the poly(1,4-butanediol adipate), hydroxyl-terminated polyoxysilane, and 2,2-dimethylolbutyric acid in a vacuum oven at 70-90℃ for 1-3 hours; (2) Using dibutyltin dilaurate as a catalyst, isophorone diisocyanate, poly(1,4-butanediol adipate) and hydroxyl-terminated polyoxysilane were added sequentially to the reaction vessel under nitrogen protection and the temperature was raised to 75-85℃ for polycondensation reaction for 1-3 hours to obtain organosilicon-modified waterborne polyurethane prepolymer P1. (3) Dissolve 2,2-dihydroxymethylbutyric acid in N-methylpyrrolidone and add it to the reaction vessel of step (2). Continue the reaction at 75-85℃ for 1-3 hours to obtain organosilicon modified waterborne polyurethane prepolymer P2. During the reaction, the viscosity of the system is appropriately controlled. (4) Cool down to 65-75℃ for the first time, add 1,4-butanediol, and carry out the chain extension reaction for 1-2 hours; (5) Cool down again to 55-65℃, add 2-butanone oxime for end-capping reaction for 2-4 hours; (6) Finally, cool down to 35-45℃, add triethylamine for neutralization, then add deionized water for high-speed emulsification for 0.5-1.5h to remove part of the solvent.

3. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 1 or 2 in waterless digital spray dyeing of polyester fabrics with disperse dyes, characterized in that, The molecular weight of poly(1,4-butanediol adipate) is 1500-3000, and the molecular weight of hydroxyl-terminated polyoxysilane is 500-1500.

4. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 1 or 2 in waterless digital spray dyeing of polyester fabrics with disperse dyes, characterized in that, The isophorone diisocyanate accounts for 29-36% of the total mass of the monomer raw materials, poly(1,4-butanediol adipate) accounts for 48-58% of the total mass of the monomers, hydroxyl-terminated polyoxysilane accounts for 2-10% of the total mass of the monomers, 2,2-dimethylolbutyric acid accounts for 4-6% of the total mass of the monomers, 1,4-butanediol accounts for 1.5-6% of the total mass of the monomers, and the catalyst dibutyltin dilaurate accounts for 0.02-0.04% of the total mass of the monomers.

5. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 2 in waterless digital spray dyeing of polyester fabrics, characterized in that, The mass of the N-methylpyrrolidone is 200-220% of the mass of 2,2-dihydroxymethylbutyric acid; the triethylamine accounts for 3-6% of the total mass of the monomers; and the amount of deionized water added accounts for 186-300% of the total mass of the monomers.

6. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 1 or 2 in waterless digital spray dyeing of polyester fabrics with disperse dyes, characterized in that, The amount of 2-butanone oxime added is calculated based on the number of moles of remaining unreacted isocyanate groups.

7. The application of the waterborne polyurethane adhesive with unidirectional disperse dye delivery function according to claim 2 in waterless digital spray dyeing of polyester fabrics, characterized in that, The emulsification speed is 750~850 rpm, and the emulsification time is 0.5~1.5 h; some solvent is removed by rotary evaporation; the rotary evaporation temperature is 35~45℃, and the rotary evaporation time is 0.5~1.5 h.

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