Polyurethane adhesive for textile pigment ink and preparation method thereof

Abstract

The invention relates to the technical field of textile printing and dyeing, in particular to a polyurethane adhesive for textile pigment ink and a preparation method of the polyurethane adhesive. The polyurethane adhesive is prepared through the combined action of the waterborne polyurethane emulsion, the solvent, the surfactant, the stabilizer, the cross-linking agent and the ethylene glycol. The prepared polyurethane adhesive is small in particle size and can present a clear printing effect; the stability is excellent, the particle size is not increased after the printing ink is compounded with color paste, and the printing quality and durability are powerfully guaranteed; the wet friction performance of a printed cloth cover is excellent, and the durability of a printed product is remarkably improved; the ethylene glycol humectant is adopted, so that the moisturizing performance of the adhesive is further improved, and particle size increase and performance reduction caused by water evaporation are effectively prevented; meanwhile, the waterborne polyurethane resin is adopted, so that the adhesive is more environment-friendly.

Description

Technical Field

[0001] The invention relates to the technical field of textile printing and dyeing, in particular to a polyurethane adhesive for textile pigment ink and a preparation method thereof. Background Art

[0002] With the continuous development of digital inkjet printing technology, the textile industry has an increasing demand for high-performance pigment inks. In this context, polyurethane binders are one of the key materials, and their performance directly affects the printing effect, quality and durability.

[0003] However, existing textile polyurethane adhesives have deficiencies in many aspects and are in urgent need of improvement. First, the particle size of existing polyurethane adhesives is generally large, which makes the printing effect unclear; second, many polyurethane adhesives have poor stability, which affects the dispersion and bonding of pigments and adhesives during the printing process, thereby affecting the stability and durability of printing quality; in addition, poor wet friction performance will reduce the durability of printed products. In summary, most polyurethane adhesives on the market are difficult to meet the growing high standards in terms of particle size stability, stability after compounding with color paste, and wet friction performance after printing on fabrics.

[0004] Therefore, we propose a polyurethane binder for textile pigment ink and a preparation method thereof. Summary of the invention

[0005] The object of the present invention is to provide a polyurethane binder for textile pigment ink and a preparation method thereof, so as to solve the problems raised in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for preparing a polyurethane binder for textile pigment ink comprises the following steps:

[0008] Step S1: under nitrogen protection, the polyol and diisocyanate are mixed evenly, reacted at 72-78° C. for 2.5-3.0 h, a chain extender is added and mixed evenly, reacted at 82-88° C. for 1.5-2.0 h, cooled to 52-58° C., dimethylol propionic acid is added, the reaction is continued for 1.5-2.0 h, triethylamine is added for neutralization reaction, and deionized water is added for emulsification and dispersion to obtain an aqueous polyurethane emulsion;

[0009] Step S2: Heat the water-based polyurethane emulsion to 82-88°C, maintain for 40-50 minutes, add a solvent and mix evenly, add a surfactant, a stabilizer and a cross-linking agent in sequence, react at 42-48°C for 2.5-3.0 hours, cool to room temperature, add ethylene glycol and mix evenly to obtain a polyurethane adhesive.

[0010] Furthermore, in step S1, the process conditions for emulsification dispersion are: stirring speed 1100-1400 rpm, emulsification time 40-50 min.

[0011] Furthermore, the polyurethane adhesive comprises the following components by weight: 65-75 parts of aqueous polyurethane emulsion, 12-18 parts of solvent, 2-4 parts of surfactant, 1.5-2.5 parts of stabilizer, 1.5-2.5 parts of crosslinking agent, and 8-10 parts of ethylene glycol.

[0012] In the above technical scheme, water-based polyurethane emulsion is used, which is more environmentally friendly; the synergistic effect of surfactants and stabilizers can effectively prevent the aggregation and precipitation of color paste particles, ensuring the high stability of the polyurethane adhesive during use, which allows the polyurethane adhesive to always maintain a stable particle size after compounding with the color paste (coating) and avoids the increase of particle size; at the same time, the added cross-linking agent can undergo a cross-linking reaction with the fiber during the printing process to form a strong chemical bond, greatly improving the durability and wet friction performance of the print; ethylene glycol is used as a humectant to effectively maintain the moisture in the adhesive, preventing the particle size from increasing and the performance from decreasing due to evaporation of water during storage and use.

[0013] Furthermore, the aqueous polyurethane emulsion comprises the following components by weight: 42-48 parts of polyol, 30-40 parts of diisocyanate, 6-9 parts of chain extender, 3.5-4.5 parts of dimethylol propionic acid, 15-20 parts of triethylamine, and 70-80 parts of deionized water.

[0014] Furthermore, the polyol is one of polyether polyol and polyester polyol.

[0015] Furthermore, the diisocyanate is one of toluene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI).

[0016] Furthermore, the chain extender is one of a small molecule diol and a diamine.

[0017] Furthermore, the solvent is one or more of deionized water, butanone, acetone, and ethyl acetate.

[0018] Furthermore, the surfactant is a non-ionic surfactant, specifically a polyoxyethylene ether surfactant.

[0019] Furthermore, the stabilizer is an organic silicon stabilizer.

[0020] Furthermore, the cross-linking agent is an aziridine cross-linking agent.

[0021] Furthermore, the aqueous polyurethane emulsion further comprises component A by weight: 10-15 parts of modified polyol.

[0022] Furthermore, the preparation method of the modified polyol is as follows:

[0023] Step (1): under nitrogen protection, magnolol, epichlorohydrin and benzyltriethylammonium chloride are mixed uniformly, reacted at 80-90° C. for 3-5 hours, cooled to 50-55° C., sodium hydroxide solution is added, and the reaction is continued for 2-3 hours. After filtering, washing and drying, epoxidized magnolol is obtained; epoxidized magnolol, organosilicon oligomer and tetrahydrofuran are mixed uniformly, reacted at 30-50° C. for 10-12 hours, filtered, washed and dried, and an organosilicon-modified epoxy compound is obtained;

[0024] Step (2): uniformly mixing the organosilicon-modified epoxy compound, 1-thioglycerol, a photoinitiator and dichloromethane, irradiating with ultraviolet light, washing and drying to obtain a polyhydroxy compound;

[0025] Step (3): uniformly mixing a polyhydroxy compound, isocyanoethyl methacrylate and hydroquinone, adding dibutyltin dilaurate, and reacting at 65-75° C. for 3-5 hours to obtain a double bond-containing monomer;

[0026] Step (4): uniformly mix the double bond-containing monomer, methyl methacrylate, octadecyl acrylate and azobis(isoheptyl)cyanocyanate, raise the temperature to 65-75° C., react for 6-8 hours, and distill under reduced pressure to obtain a modified polyol.

[0027] In the above technical scheme, the bio-based compound magnolia officinalis is used as a raw material, which reacts with epichlorohydrin to obtain epoxidized magnolia officinalis containing two epoxy groups and a carbon-carbon double bond, and the epoxidized magnolia officinalis and an organosilicon oligomer are subjected to a ring-opening reaction to generate hydroxyl groups to obtain an organosilicon-modified epoxy compound; under the action of a photoinitiator, the carbon-carbon double bond in the organosilicon-modified epoxy compound is subjected to a thiol-ene click reaction with 1-thioglycerol to obtain a polyhydroxy compound; then the polyhydroxy compound is reacted with isocyanoethyl methacrylate to introduce a double bond to obtain a double bond-containing monomer, which is reacted with methyl methacrylate and octadecyl acrylate under the action of an initiator to obtain a modified polyol.

[0028] Furthermore, in the step (1), the mass ratio of magnolol, epichlorohydrin, benzyltriethylammonium chloride and sodium hydroxide solution is 1:(2-3):(0.05-0.08):(0.5-1.0), and the concentration of the sodium hydroxide solution is 30-40wt%.

[0029] Furthermore, in the step (1), the mass ratio of epoxidized magnolol, organosilicon oligomer and tetrahydrofuran is 1:(1.8-2.2):(4-6).

[0030] Furthermore, the preparation method of the organosilicon oligomer is as follows:

[0031] Under nitrogen protection, dimethyldiethoxysilane, anhydrous ethanol and deionized water are mixed evenly, the temperature is raised to 50-60°C, the pH is adjusted to 10-11 with ammonia water, and a mixed solution of 3-aminopropyltriethoxysilane, anhydrous ethanol and deionized water is added, the reaction is carried out for 2-4 hours, and the organosilicon oligomer is obtained after filtration.

[0032] Furthermore, the mass ratio of the dimethyldiethoxysilane to anhydrous ethanol and deionized water is 1:(200-400):(6-12).

[0033] Furthermore, the mass ratio of the 3-aminopropyltriethoxysilane to anhydrous ethanol and deionized water is 1:(50-60):(2-4), and the mass of 3-aminopropyltriethoxysilane is 5-10 times that of dimethyldiethoxysilane.

[0034] Furthermore, the concentration of the ammonia water is 28wt%.

[0035] In the above technical solution, the organosilicon oligomer is prepared by condensation reaction of dimethyldiethoxysilane and 3-aminopropyltriethoxysilane (KH-550), which not only significantly improves the stability of the organosilicon oligomer, but also retains the amino function therein.

[0036] Furthermore, in the step (2), the mass ratio of the organosilicon-modified epoxy compound, 1-thioglycerol, photoinitiator and dichloromethane is 1:(0.5-0.7):(0.3-0.5):(2-3).

[0037] Furthermore, the photoinitiator is 2-hydroxy-2-methyl-1-phenyl-1-propanone.

[0038] Furthermore, in step (2), the ultraviolet irradiation process conditions are: irradiation with 360-400nm ultraviolet light for 4-6h, irradiation intensity of 20-35mW / cm 2 .

[0039] Furthermore, in the step (3), the mass ratio of the polyhydroxy compound, isocyanoethyl methacrylate, hydroquinone and dibutyltin dilaurate is 1:(0.1-0.3):(0.005-0.010):(0.005-0.010).

[0040] Furthermore, in the step (4), the mass ratio of the double bond-containing monomer to methyl methacrylate, octadecyl acrylate, and azobisisoheptanenitrile is 1:(2-3):(0.5-1.0):(0.03-0.05).

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. A polyurethane adhesive for textile pigment ink and a preparation method thereof of the present invention are prepared by the joint action of aqueous polyurethane emulsion, solvent, surfactant, stabilizer, cross-linking agent and ethylene glycol. The polyurethane adhesive has a small particle size (≤0.5 μm) and can present a clear printing effect; the stability is extremely excellent, and the particle size remains unchanged after being placed in an environment of 60°C for 4 weeks, and the particle size does not increase after compounding with the color paste, which effectively guarantees the quality and durability of the printing; the wet friction performance after printing on the cloth surface is excellent and can reach above level 2, which significantly improves the durability of the printed product; the use of ethylene glycol moisturizing agent further improves the moisturizing performance of the adhesive, effectively preventing the increase of particle size and performance degradation caused by water evaporation; at the same time, the use of aqueous polyurethane resin makes the adhesive more environmentally friendly and conforms to the development trend of the modern textile printing and dyeing industry.

[0043] 2. A polyurethane binder for textile pigment ink and a preparation method thereof of the present invention, wherein magnolol is a hydrophobic biphenol structural compound and also has antibacterial properties; magnolol, a bio-based compound, is used as a raw material and reacts with epichlorohydrin to obtain epoxidized magnolol containing two epoxy groups and a carbon-carbon double bond; an organosilicon oligomer is introduced into the epoxidized magnolol through grafting modification; a soft segment Si-O-Si skeleton is used to reduce its flexibility, further reduce the glass transition temperature and surface tension, improve the dispersion performance and lubricity, and generate hydroxyl groups to obtain an organosilicon-modified epoxidized magnolol. The invention discloses a novel polyol having a carbon-carbon double bond and a thiol-ene double bond. The polyol has ... DETAILED DESCRIPTION

[0044] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In this embodiment, the polyol is polyester polyol, brand BY-3113; diisocyanate: diphenylmethane diisocyanate; chain extender: 1,4-butanediol; surfactant: fatty alcohol polyoxyethylene ether AEO-9; stabilizer: silicone stabilizer, brand BYK-8020; cross-linker: aziridine cross-linker, model HG-100, sourced from Guangzhou Hangeng New Materials Co., Ltd.

[0046] In the following examples and comparative examples, 1 part is equal to 10 g.

[0047] Example 1: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0048] Step S1: Under nitrogen protection, 42 parts of polyol and 30 parts of diisocyanate were mixed evenly, reacted at 72° C. for 2.5 hours, 6 parts of chain extender were added and mixed evenly, reacted at 82° C. for 1.5 hours, cooled to 52° C., 3.5 parts of dimethylol propionic acid were added, and the reaction was continued for 1.5 hours, 15 parts of triethylamine were added for neutralization reaction, and 70 parts of deionized water were added for emulsification and dispersion (stirring speed 1100 rpm, emulsification time 40 min) to obtain an aqueous polyurethane emulsion;

[0049] Step S2: Heat 72 parts of aqueous polyurethane emulsion to 82°C, maintain for 40 minutes, add 16 parts of butanone and mix evenly, add 3 parts of surfactant, 2 parts of stabilizer and 2 parts of cross-linking agent in sequence, react at 42°C for 2.5 hours, cool to room temperature, add 8 parts of ethylene glycol and mix evenly to obtain a polyurethane adhesive.

[0050] Example 2: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0051] Step S1: Under nitrogen protection, 45 parts of polyol and 35 parts of diisocyanate were mixed evenly, reacted at 75° C. for 2.8 hours, 8 parts of chain extender were added and mixed evenly, reacted at 85° C. for 1.8 hours, cooled to 55° C., 4 parts of dimethylol propionic acid were added, and the reaction was continued for 1.8 hours, 18 parts of triethylamine were added for neutralization reaction, and 75 parts of deionized water were added for emulsification and dispersion (stirring speed 1300 rpm, emulsification time 45 min) to obtain an aqueous polyurethane emulsion;

[0052] Step S2: Heat 68 parts of aqueous polyurethane emulsion to 85°C, maintain for 45 minutes, add 17 parts of butanone and mix evenly, add 3.5 parts of surfactant, 2 parts of stabilizer and 2.2 parts of cross-linking agent in sequence, react at 45°C for 2.8 hours, cool to room temperature, add 9 parts of ethylene glycol and mix evenly to obtain a polyurethane adhesive.

[0053] Embodiment 3: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0054] Step S1: Under nitrogen protection, 48 parts of polyol and 40 parts of diisocyanate were mixed evenly, reacted at 78° C. for 3.0 h, 9 parts of chain extender were added and mixed evenly, reacted at 88° C. for 2.0 h, cooled to 58° C., 4.5 parts of dimethylol propionic acid were added, and the reaction was continued for 2.0 h, 20 parts of triethylamine were added for neutralization reaction, and 80 parts of deionized water were added for emulsification and dispersion (stirring speed 1400 rpm, emulsification time 50 min) to obtain an aqueous polyurethane emulsion;

[0055] Step S2: Heat 74 parts of aqueous polyurethane emulsion to 88°C, maintain for 50 minutes, add 14 parts of butanone and mix evenly, add 3.2 parts of surfactant, 2.3 parts of stabilizer and 2.1 parts of cross-linking agent in sequence, react at 48°C for 3.0 hours, cool to room temperature, add 10 parts of ethylene glycol and mix evenly to obtain a polyurethane adhesive.

[0056] Embodiment 4: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0057] Step S1: Under nitrogen protection, 45 parts of polyol, 10 parts of modified polyol and 35 parts of diisocyanate were mixed evenly, reacted at 75°C for 2.8 hours, 8 parts of chain extender were added and mixed evenly, reacted at 85°C for 1.8 hours, cooled to 55°C, 4 parts of dimethylol propionic acid were added, and the reaction was continued for 1.8 hours, 18 parts of triethylamine were added for neutralization reaction, and 75 parts of deionized water were added for emulsification and dispersion (stirring speed 1300 rpm, emulsification time 45 min) to obtain an aqueous polyurethane emulsion;

[0058] Step S2: 65 parts of water-based polyurethane emulsion are heated to 82° C., maintained for 40 minutes, 12 parts of butanone are added and mixed evenly, 2 parts of surfactant, 1.5 parts of stabilizer and 1.5 parts of cross-linking agent are added in sequence, reacted at 42° C. for 2.5 hours, cooled to room temperature, 8 parts of ethylene glycol are added and mixed evenly, and a polyurethane adhesive is obtained;

[0059] The preparation method of modified polyol is as follows:

[0060] Step (1): Under nitrogen protection, 10 parts of magnolol, 20 parts of epichlorohydrin and 0.5 parts of benzyltriethylammonium chloride are mixed uniformly, reacted at 80°C for 3 hours, cooled to 50°C, 5 parts of 30wt% sodium hydroxide solution are added, and the reaction is continued for 2 hours. After filtering, washing and drying, epoxidized magnolol is obtained; 10 parts of epoxidized magnolol, 18 parts of organosilicon oligomer and 40 parts of tetrahydrofuran are mixed uniformly, reacted at 30°C for 10 hours, filtered, washed and dried, and an organosilicon-modified epoxy compound is obtained;

[0061] Step (2): 10 parts of organosilicon-modified epoxy compound, 5 parts of 1-thioglycerol, 3 parts of photoinitiator and 20 parts of dichloromethane were mixed evenly, and irradiated with 360nm ultraviolet light for 4 hours with an irradiation intensity of 20mW / cm 2 , washing and drying to obtain a polyhydroxy compound;

[0062] Step (3): 10 parts of a polyhydroxy compound, 1 part of isocyanoethyl methacrylate and 0.05 parts of hydroquinone are mixed evenly, 0.5 parts of dibutyltin dilaurate are added, and the mixture is reacted at 65° C. for 3 hours to obtain a double bond-containing monomer;

[0063] Step (4): 10 parts of a double bond-containing monomer, 20 parts of methyl methacrylate, 5 parts of octadecyl acrylate, and 0.3 parts of azobisisoheptanenitrile are mixed uniformly, the mixture is heated to 65° C., reacted for 6 hours, and subjected to reduced pressure distillation to obtain a modified polyol;

[0064] The preparation method of organosilicon oligomer is as follows:

[0065] Under nitrogen protection, 4 parts of dimethyldiethoxysilane, 800 parts of anhydrous ethanol and 24 parts of deionized water were mixed evenly, the temperature was raised to 50°C, the pH was adjusted to 10 with aqueous ammonia, and a mixed solution of 20 parts of 3-aminopropyltriethoxysilane, 1000 parts of anhydrous ethanol and 40 parts of deionized water was added, the reaction was carried out for 2 hours, and the organosilicon oligomer was obtained after filtration.

[0066] Embodiment 5: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0067] Step S1: Under nitrogen protection, 45 parts of polyol, 12 parts of modified polyol and 35 parts of diisocyanate were mixed evenly, reacted at 75° C. for 2.8 hours, 8 parts of chain extender were added and mixed evenly, reacted at 85° C. for 1.8 hours, cooled to 55° C., 4 parts of dimethylol propionic acid were added, and the reaction was continued for 1.8 hours, 18 parts of triethylamine were added for neutralization reaction, and 75 parts of deionized water were added for emulsification and dispersion (stirring speed 1300 rpm, emulsification time 45 min) to obtain an aqueous polyurethane emulsion;

[0068] Step S2: 70 parts of water-based polyurethane emulsion are heated to 85°C, maintained for 45 minutes, 15 parts of deionized water are added and mixed evenly, 3 parts of surfactant, 2 parts of stabilizer and 2 parts of cross-linking agent are added in sequence, reacted at 45°C for 2.8 hours, cooled to room temperature, 9 parts of ethylene glycol are added and mixed evenly, and a polyurethane adhesive is obtained;

[0069] The preparation method of modified polyol is as follows:

[0070] Step (1): Under nitrogen protection, 12 parts of magnolol, 30 parts of epichlorohydrin and 0.72 parts of benzyltriethylammonium chloride are mixed uniformly, reacted at 85°C for 4 hours, cooled to 52°C, 9.6 parts of 35wt% sodium hydroxide solution are added, and the reaction is continued for 2-3 hours. After filtering, washing and drying, epoxidized magnolol is obtained; 12 parts of epoxidized magnolol, 24 parts of organosilicon oligomer and 60 parts of tetrahydrofuran are mixed uniformly, reacted at 40°C for 11 hours, filtered, washed and dried to obtain organosilicon-modified epoxy compound;

[0071] Step (2): 12 parts of organosilicon-modified epoxy compound, 7.2 parts of 1-thioglycerol, 4.8 parts of photoinitiator and 30 parts of dichloromethane were mixed evenly, and irradiated with 380nm ultraviolet light for 5 hours with an irradiation intensity of 30mW / cm 2 , washing and drying to obtain a polyhydroxy compound;

[0072] Step (3): 12 parts of a polyhydroxy compound, 2.4 parts of isocyanoethyl methacrylate and 0.096 parts of hydroquinone are mixed evenly, 0.1 parts of dibutyltin dilaurate are added, and the mixture is reacted at 70° C. for 4 hours to obtain a double bond-containing monomer;

[0073] Step (4): 10 parts of a double bond-containing monomer, 25 parts of methyl methacrylate, 8 parts of octadecyl acrylate, and 0.4 parts of azobisisoheptanenitrile are mixed uniformly, the mixture is heated to 70° C., reacted for 7 hours, and subjected to reduced pressure distillation to obtain a modified polyol;

[0074] The preparation method of organosilicon oligomer is as follows:

[0075] Under nitrogen protection, 5 parts of dimethyldiethoxysilane, 1500 parts of anhydrous ethanol and 50 parts of deionized water were mixed evenly, the temperature was raised to 55°C, the pH was adjusted to 10.5 with ammonia water, and a mixed solution of 40 parts of 3-aminopropyltriethoxysilane, 2200 parts of anhydrous ethanol and 120 parts of deionized water was added, the reaction was carried out for 3 hours, and the organosilicon oligomer was obtained after filtration.

[0076] Example 6: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0077] Step S1: Under nitrogen protection, 45 parts of polyol, 15 parts of modified polyol and 35 parts of diisocyanate were mixed evenly, reacted at 75°C for 2.8 hours, 8 parts of chain extender were added and mixed evenly, reacted at 85°C for 1.8 hours, cooled to 55°C, 4 parts of dimethylol propionic acid were added, and the reaction was continued for 1.8 hours, 18 parts of triethylamine were added for neutralization reaction, and 75 parts of deionized water were added for emulsification and dispersion (stirring speed 1300rpm, emulsification time 45min) to obtain an aqueous polyurethane emulsion;

[0078] Step S2: 75 parts of water-based polyurethane emulsion are heated to 88° C., maintained for 50 min, 18 parts of butanone are added and mixed evenly, 4 parts of surfactant, 2.5 parts of stabilizer and 2.5 parts of cross-linking agent are added in sequence, reacted at 48° C. for 3.0 h, cooled to room temperature, 10 parts of ethylene glycol are added and mixed evenly, and a polyurethane adhesive is obtained;

[0079] The preparation method of modified polyol is as follows:

[0080] Step (1): Under nitrogen protection, 15 parts of magnolol, 45 parts of epichlorohydrin and 0.12 parts of benzyltriethylammonium chloride are mixed uniformly, reacted at 80-90° C. for 5 hours, cooled to 55° C., 15 parts of 40wt% sodium hydroxide solution are added, and the reaction is continued for 3 hours. After filtering, washing and drying, epoxidized magnolol is obtained; 15 parts of epoxidized magnolol, 33 parts of organosilicon oligomer and 90 parts of tetrahydrofuran are mixed uniformly, reacted at 50° C. for 12 hours, filtered, washed and dried to obtain organosilicon-modified epoxy compound;

[0081] Step (2): 15 parts of organosilicon-modified epoxy compound, 10.5 parts of 1-thioglycerol, 7.5 parts of photoinitiator and 45 parts of dichloromethane were mixed evenly, and irradiated with 400nm ultraviolet light for 6 hours with an irradiation intensity of 35mW / cm 2 , washing and drying to obtain a polyhydroxy compound;

[0082] Step (3): 15 parts of a polyhydroxy compound, 4.5 parts of isocyanoethyl methacrylate and 0.15 parts of hydroquinone are mixed evenly, 0.15 parts of dibutyltin dilaurate are added, and the mixture is reacted at 75° C. for 5 hours to obtain a double bond-containing monomer;

[0083] Step (4): 10 parts of a double bond-containing monomer, 30 parts of methyl methacrylate, 10 parts of octadecyl acrylate, and 0.5 parts of azobisisoheptanenitrile are mixed uniformly, the mixture is heated to 75° C., reacted for 8 hours, and subjected to reduced pressure distillation to obtain a modified polyol;

[0084] The preparation method of organosilicon oligomer is as follows:

[0085] Under nitrogen protection, 5 parts of dimethyldiethoxysilane, 2000 parts of anhydrous ethanol and 60 parts of deionized water were mixed evenly, the temperature was raised to 60°C, the pH was adjusted to 11 with ammonia water, and a mixed solution of 50 parts of 3-aminopropyltriethoxysilane, 3000 parts of anhydrous ethanol and 200 parts of deionized water was added, the reaction was carried out for 4 hours, and the organosilicon oligomer was obtained after filtration.

[0086] Comparative Example 1: The polyurethane adhesive comprises the following components by weight: 72 parts of aqueous polyurethane emulsion, 16 parts of solvent, 2 parts of stabilizer, 2 parts of cross-linking agent, and 8 parts of ethylene glycol; compared with Example 1, Comparative Example 1 does not add a surfactant, and other steps and processes are the same as Example 1.

[0087] Comparative Example 2: The aqueous polyurethane emulsion comprises the following components by weight: 45 parts of polyol, 12 parts of modified polyol, 35 parts of diisocyanate, 8 parts of chain extender, 4 parts of dimethylolpropionic acid, 18 parts of triethylamine, and 75 parts of deionized water; compared with Example 5, 5 parts of modified polyol are added in Comparative Example 2, and the other steps and processes are the same as those in Example 5.

[0088] Comparative Example 3: A method for preparing a polyurethane binder for textile pigment ink, comprising the following process:

[0089] Compared with Example 5, in Comparative Example 3, the modified polyol is replaced with a polyhydroxy compound of the same mass, and the other steps are the same as those of Example 5.

[0090] Experiment: The polyurethane adhesives obtained in Examples 1-6 and Comparative Examples 1-3 were used to prepare samples, and their properties were tested and the test results were recorded:

[0091] Experiment 1: Particle size test: The particle size of the polyurethane adhesive was tested using a laser particle size analyzer.

[0092] Experiment 2: Stability test:

[0093] High temperature stability test: The polyurethane adhesive was placed in a 60°C constant temperature box for 4 weeks. Samples were taken regularly every week and the particle size was tested using a laser particle size analyzer.

[0094] Stability test of compounding with color paste: The polyurethane adhesive and color paste (Clariant Colanyl water-based color paste black N131-CN) were compounded in a mass ratio of 2:3 to obtain ink, which was then placed at room temperature. Samples were taken on the 1st, 3rd, 5th and 7th days to test the particle size.

[0095] Experiment 3: wet friction performance test: The wet friction performance was tested according to the national standard GB / T 3920-2008 "Textiles - Tests for Colour Fastness - Colour Fastness to Friction". The ink prepared above was subjected to an inkjet printing test on cotton cloth without pretreatment to obtain a printed cotton cloth containing the polyurethane adhesive of the present invention. The printed cotton cloth was fixed on a friction tester and rubbed with a standard friction cloth under a certain pressure. The running speed was 1 reciprocating friction cycle per second, for a total of 10 friction cycles, with a load of 9N, and the liquid carrying rate of the wet friction sample was 100%.

[0096] The test results are as follows:

[0097]

[0098] According to the data in the above table, we can clearly draw the following conclusions:

[0099] 1. Compared with Examples 1-6, the particle size of the product obtained in Comparative Example 1 becomes larger, indicating that the surfactant added in the present invention can synergistically act with the stabilizer to improve the dispersibility and stability of the emulsion.

[0100] 2. Compared with Examples 4-6, the wet friction fastness of the product obtained in Comparative Example 2 is reduced. It can be seen that the performance of the aqueous polyurethane emulsion prepared by the present invention is affected by its component ratio. By selecting the component ratio within the said range, a polyurethane adhesive with excellent performance can be prepared.

[0101] 3. Compared with Examples 1-3, the wet rubbing fastness of the product obtained in Comparative Example 3 decreases, which indicates that compared with hydroxy compounds, the modified polyol prepared by the present invention has better stability and abrasion resistance, thereby improving the wet rubbing fastness of the final product.

[0102] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for preparing a polyurethane binder for textile pigment ink, characterized in that: The steps include: Step S1: under nitrogen protection, the polyol and diisocyanate are mixed evenly, reacted at 72-78° C. for 2.5-3.0 h, a chain extender is added and mixed evenly, reacted at 82-88° C. for 1.5-2.0 h, cooled to 52-58° C., dimethylol propionic acid is added, the reaction is continued for 1.5-2.0 h, triethylamine is added for neutralization reaction, and deionized water is added for emulsification and dispersion to obtain an aqueous polyurethane emulsion; Step S2: Heat the water-based polyurethane emulsion to 82-88°C, maintain for 40-50 minutes, add a solvent and mix evenly, add a surfactant, a stabilizer and a cross-linking agent in sequence, react at 42-48°C for 2.5-3.0 hours, cool to room temperature, add ethylene glycol and mix evenly to obtain a polyurethane adhesive.

2. The method for preparing a polyurethane binder for textile pigment ink according to claim 1, characterized in that: The polyurethane adhesive comprises the following components by weight: 65-75 parts of waterborne polyurethane emulsion, 12-18 parts of solvent, 2-4 parts of surfactant, 1.5-2.5 parts of stabilizer, 1.5-2.5 parts of crosslinking agent and 8-10 parts of ethylene glycol.

3. The method for preparing a polyurethane binder for textile pigment ink according to claim 2, characterized in that: The solvent is one or more of deionized water, butanone, acetone, and ethyl acetate.

4. The method for preparing a polyurethane binder for textile pigment ink according to claim 2, characterized in that: The surfactant is a non-ionic surfactant, specifically a polyoxyethylene ether surfactant.

5. The method for preparing a polyurethane binder for textile pigment ink according to claim 2, characterized in that: The stabilizer is an organosilicon stabilizer.

6. The method for preparing a polyurethane binder for textile pigment ink according to claim 2, characterized in that: The cross-linking agent is an aziridine cross-linking agent.

7. The method for preparing a polyurethane binder for textile pigment ink according to claim 2, characterized in that: The aqueous polyurethane emulsion comprises the following components by weight: 42-48 parts of polyol, 30-40 parts of diisocyanate, 6-9 parts of chain extender, 3.5-4.5 parts of dimethylol propionic acid, 15-20 parts of triethylamine and 70-80 parts of deionized water.

8. The method for preparing a polyurethane binder for textile pigment ink according to claim 7, characterized in that: The polyol is one of polyether polyol and polyester polyol.

9. The method for preparing a polyurethane binder for textile pigment ink according to claim 7, characterized in that: The aqueous polyurethane emulsion further comprises component A by weight: 10-15 parts of modified polyol.

10. The method for preparing a polyurethane binder for textile pigment ink according to claim 9, characterized in that: The preparation method of the modified polyol is as follows: Step (1): under nitrogen protection, magnolol, epichlorohydrin and benzyltriethylammonium chloride are mixed uniformly, reacted at 80-90° C. for 3-5 hours, cooled to 50-55° C., sodium hydroxide solution is added, and the reaction is continued for 2-3 hours. After filtering, washing and drying, epoxidized magnolol is obtained; epoxidized magnolol, organosilicon oligomer and tetrahydrofuran are mixed uniformly, reacted at 30-50° C. for 10-12 hours, filtered, washed and dried, and an organosilicon-modified epoxy compound is obtained; Step (2): uniformly mixing the organosilicon-modified epoxy compound, 1-thioglycerol, a photoinitiator and dichloromethane, irradiating with ultraviolet light, washing and drying to obtain a polyhydroxy compound; Step (3): uniformly mixing a polyhydroxy compound, isocyanoethyl methacrylate and hydroquinone, adding dibutyltin dilaurate, and reacting at 65-75° C. for 3-5 hours to obtain a double bond-containing monomer; Step (4): uniformly mix the double bond-containing monomer, methyl methacrylate, octadecyl acrylate and azobis(isoheptyl)cyanocyanate, raise the temperature to 65-75° C., react for 6-8 hours, and distill under reduced pressure to obtain a modified polyol.

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