Preparation method and application of fabric multilayer deepening agent

Abstract

The invention discloses a preparation method and application of a multi-layer fabric deepening agent. The preparation method comprises the following steps: uniformly mixing a linear body, a piperazine coupling agent and a tetramethylammonium hydroxide catalyst, heating, cooling, adding acid, stirring and discharging to obtain piperazine polysiloxane; reacting piperazine polysiloxane with epoxy terminated polyether to obtain polyether block piperazine silicone oil; mixing the monomer 1 with polyether block piperazine silicone oil, heating, and cooling to room temperature; adding an emulsifier, a cosolvent, an initiator and water, and reacting to obtain a polyether block piperazine silicone oil-soft emulsion particle emulsion; adding a monomer 2 for forming hard latex particles and a cross-linking agent into an emulsifier, heating, and adding an initiator and water to obtain a hard latex particle aqueous dispersion; and mixing the polyether block piperazine silicone oil-soft latex particle emulsion with the hard latex particle aqueous dispersion to obtain the multi-layer structure deepening agent. A multi-layer structure can be formed on the surface of the fabric, the refractive index of the surface of the fabric is reduced, the deepening and brightening effects are achieved, and the stability is good.

Description

Technical Field

[0001] The invention relates to the technical field of textile printing and dyeing auxiliaries, and in particular to a preparation method and application of a fabric multi-layer darkening agent. Background Art

[0002] With the increasing attention paid to environmental protection around the world, the production cost of dyeing factories is also increasing. In order to reduce costs, reducing the amount of dyes has become an inevitable choice. However, this will lead to a decrease in dyeing depth, affecting the appearance and quality of the product. In this market situation, darkening agents came into being. Darkening agents are chemical substances that can increase the depth of dyeing. They can increase the depth of dyeing by changing the degree of reflection and refraction of light by fibers, so that while reducing the amount of dyes, the depth of dyeing can also be guaranteed not to decrease. Among them, the refractive index difference between polyester fiber (nf = 1.73) and air (n0 = 1.0) is large, so that the incident light is reflected in large quantities at the surface of polyester fiber. Since these reflected lights are not selectively absorbed by the dyes, they cannot form colored light, resulting in poor color saturation of polyester fabrics, and it is difficult to present dark green, navy blue, purple red, ink black and other dark color effects. In particular, as the fiber fineness decreases, the reflective surface area of ​​the fabric increases dramatically, and the enhanced reflected light makes the dyed fabric often present a "white" visual effect. At present, the existing darkening agents mainly roughen the surface of fabric fibers to produce fine bumps on the fiber surface, and the irregular reflective layer will produce a certain dark effect. However, there are still some problems with the existing darkening agents. First, the amount of darkening agent used is large to obtain the ideal darkening effect, which undoubtedly increases the production cost. Secondly, the existing darkening agents have poor synergistic effects, and dark colors are not deep and black colors are not black, which will affect the appearance and quality of the product. Finally, after the darkening agent is post-treated, the cost of sewage treatment is very high, and even post-treatment measures such as discharge ban are required, which also limits the use of darkening agents. At present, low-refractive index resins are mainly used to darken fabrics in the post-finishing process. A layer of low-refractive index resin is covered on the surface of dark fabrics to reduce the amount of light reflected on the fabric surface, thereby increasing the apparent color depth of the fabric. In order to protect the environment and respond to the strict high demand of the market, based on the above-mentioned problems, it is particularly important to develop a multi-layer darkening agent to efficiently treat textiles, and the market prospects are very broad.

[0003] Chinese invention patent CN116607329A discloses a fabric darkening agent and its preparation method and application. The fabric darkening agent comprises the following raw materials in parts by weight: 20-40 parts of fluorinated amino silicone oil, 10-25 parts of nano-silicon dioxide dispersion, 2-6 parts of emulsifier, and 60-100 parts of water; and the fluorinated amino silicone oil comprises the following raw materials in parts by weight: 40-80 parts of terminal hydroxyl silicone oil, 20-40 parts of fluorinated amino coupling agent, and 0.1-1 part of alkaline catalyst; the preparation method of the fabric darkening agent is to first add the emulsifier into water, stir and mix 0.5-10 parts of water, and then ... n, then add nano-silicon dioxide dispersion, continue stirring for 1 to 2 hours, and finally add fluorinated amino silicone oil, homogenize for 20 to 50 minutes, and adjust the pH to neutral to obtain; the obtained fabric deepening agent provides insufficient rough surface construction and low refractive index, and the fabric feels rough and non-hydrophilic; Chinese invention patent CN104672460B introduces that octamethylcyclotetrasiloxane (D4) and piperazine double heads are reacted in proportion in the presence of an alkaline catalyst to prepare double-terminal piperazine silicone oil, and then the silicone oil is reacted with a double-terminal epoxy-terminated polyether to prepare a polyether block piperazine silicone oil. The silicone oil is emulsified and used for the finishing of cotton fabrics. The treated fabrics not only have good softness, but also have good hydrophilicity, hygroscopicity, anti-yellowing properties, etc., but have no deepening effect. The method described in Chinese invention patent CN105113246B constructs a nano-rough surface on the surface of polyester fabric by blending soft and hard particles, thereby achieving anti-reflection and depth enhancement of polyester, but the fabric feels rough and does not repel water. Summary of the invention

[0004] In order to solve the above problems, the present invention aims to provide a method for preparing a multi-layer darkening agent and its application, which is a polyether block piperazine silicone oil-soft latex particle emulsion blended with hard particles to construct a nano-rough surface on the surface of polyester fabric, so that the prepared darkening agent has good hydrophilicity and stability; and can make the treated fabric non-water-repellent. The main characteristics of the synthetic process are solvent-free, non-water-repellent and low-cost, which is particularly important for industrially produced functional darkening agents and has a very broad market prospect.

[0005] The technical solution of the present invention is as follows: A method for preparing a multi-layered darkening agent, the method comprising the following steps: (1) Preparation of polyether block piperazine silicone oil: First, the silane coupling agent, DMC and tetramethylammonium hydroxide are mixed evenly, and the temperature is raised to react to obtain a piperazine coupling agent. Then, the linear body, piperazine coupling agent and tetramethylammonium hydroxide catalyst are mixed evenly, nitrogen is passed to deoxygenate, the temperature is raised, a vacuum is drawn, the temperature is raised to react, the temperature is raised again, the temperature is kept, the acid is added after cooling, and the material is stirred to obtain piperazine polysiloxane; the piperazine polysiloxane is then reacted with an epoxy-terminated polyether to obtain a polyether block piperazine silicone oil; (2) Preparation of polyether block piperazine silicone oil-soft latex particle emulsion: fully stir an emulsifier and water to form an emulsifier aqueous solution, mix the monomer 1 used to form soft latex particles with the polyether block piperazine silicone oil obtained in step (1), pass nitrogen to deoxygenate, heat up, cool to room temperature, then add to a mixture of the emulsifier aqueous solution and the co-solvent in equal mass ratios, add an initiator and water, react and continue to keep warm to obtain a polyether block piperazine silicone oil-soft latex particle emulsion; (3) Preparation of hard latex particle aqueous dispersion: fully stir the emulsifier and water, add monomer 2 and a cross-linking agent for forming hard latex particles into the emulsifier aqueous solution, pass nitrogen to deoxygenate, increase the temperature, add an initiator and water, react and keep the temperature continuously to obtain a hard latex particle aqueous dispersion; (4) Preparation of a multilayer structured darkening agent: The polyether block piperazine silicone oil-soft latex particle emulsion obtained in step (2) is mixed with the hard latex particle aqueous dispersion obtained in step (3) to obtain a multilayer structured darkening agent.

[0006] Preferably, the silane coupling agent in step (1) is 3-piperazinepropylmethyldimethoxysilane; the linear phase is dihydroxylated polydimethylsiloxane with a viscosity of 60-80 cst; the purity of DMC (dimethylcyclosiloxane mixture) is greater than or equal to 99.5%, and the volatile content is less than 1%; the mass ratio of DMC (dimethylcyclosiloxane mixture), silane coupling agent, and tetramethylammonium hydroxide is (8-12): (0.5-1): (0.2-0.5); the mass ratio of the linear phase, piperazine coupling agent, and tetramethylammonium hydroxide is (85-95): (4-5.5): (0.02-0.06).

[0007] Further preferably, in the step (1), the preparation of the polyether block piperazine silicone oil is as follows: first, the silane coupling agent, DMC and tetramethylammonium hydroxide are mixed evenly, and the temperature is raised to 120-130°C as the piperazine coupling agent. Then, the linear body, the piperazine coupling agent and the tetramethylammonium hydroxide catalyst are mixed evenly, nitrogen is passed through to deoxygenate for 5-15 minutes, the temperature is raised to 72-78°C, vacuum is pulled, the temperature is continued to be raised to 110-125°C for insulation reaction for 2-4 hours, and then the temperature is raised to 130-150°C for insulation reaction for 1-2 hours, cooled and acid is added, stirred for 25-35 minutes to obtain the piperazine polysiloxane; then the silicone oil is reacted with the epoxy-terminated polyether in an equimolar mass ratio and added to the container, 25-35wt.% of the total amount of the reactants is added as butyl ether as a solvent, the temperature is raised to 70-80°C, and the reaction is carried out for 2-4 hours to prepare the polyether block piperazine silicone oil. Preferably, in step (2), the following raw materials are used in parts by weight: 60-95 parts of water; 3-12 parts of polyether block piperazine silicone oil; Emulsifier 0.01-5 parts; 1 to 6 parts of co-solvent; Monomer 1 10-45 parts; Initiator 0.001~0.9 parts.

[0008] Further preferably, the emulsifier is a mixture of one or more of sodium dodecyl sulfate, sodium alkyl sulfonate, sodium dodecylbenzene sulfonate, and isooctylphenyl glycoside; the cosolvent is isomeric decyl alcohol polyoxyethylene ether (isomeric fatty decyl alcohol polyoxyethylene ether, at least one or more mixtures of BASF's XL-40, XL-50, XL-60, XL-70, XL-80, XL-90, XP30, XP50, XP70 and XP90) or fatty alcohol polyoxyethylene ether (at least one or more mixtures of BASF's AE0-3, AE0-5, AE0-7 and AE0-9). Further preferably, in step (2), the monomer 1 is a mixture of one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, and isobornyl acrylate; and the initiator is a mixture of one or more of potassium persulfate and ammonium persulfate.

[0009] Preferably, in step (2), nitrogen is passed to deoxygenate for 10 to 20 minutes, the temperature is raised to 85 to 95°C, and after the reaction is completed, the mixture is cooled to room temperature and then added to the emulsifier aqueous solution, an initiator and water are added, the reaction is continued for 2 to 3 hours, and the temperature is kept constant for 40 to 55 minutes.

[0010] Preferably, in step (3), the following raw materials are used in parts by weight: 60-93 parts of water; Emulsifier 0.01-3 parts; Monomer 2 10-30 parts; 1 to 6 parts of cross-linking agent; Initiator 0.001-0.9 parts; The monomer 2 is one or a mixture of methyl methacrylate and ethyl methacrylate; the emulsifier is one or a mixture of sodium dodecyl sulfate, sodium alkyl sulfonate, sodium dodecylbenzene sulfonate, isooctylphenyl glycoside; the initiator is one or a mixture of potassium persulfate and ammonium persulfate; The crosslinking agent is one of divinylbenzene and ethylene glycol dimethacrylate.

[0011] In the step (4), the mass ratio of the hard latex particle aqueous dispersion: the polyether block piperazine silicone oil-soft latex particle emulsion is 1:(1-9).

[0012] The multi-layer structure deepening agent prepared by the preparation method.

[0013] The multi-layer structure darkening agent is used in darkening finishing of polyester fabric. The hard latex particles arranged on the surface of the fabric have a high glass transition temperature and can retain the original morphology unchanged. The piperazine group and the hydrophilic polyether segment in the treated piperazine coupling agent are more easily combined and located on the main chain of the polymer, and can effectively avoid the sticking phenomenon during the reaction of the polyether block piperazine silicone oil, and can improve the emulsification ability of the silicone oil and the stability of the emulsion. The polyether block piperazine silicone oil-soft latex particles form a film after being heated, which can not only form a multi-level structure on the surface of the fabric, but also reduce the refractive index of the fabric surface, achieve the effect of deepening and brightening and has good stability, and at the same time make the fabric feel particularly smooth, soft, and have a certain hydrophilicity, which is energy-saving and environmentally friendly, saves dyes and reduces costs.

[0014] The advantages of the present invention are: (1) The preparation process is simple and the cost is low.

[0015] (2) The technical process is solvent-free, has high yield and is environmentally friendly.

[0016] (3) Product structure design: multi-layer deepening agent.

[0017] (4) The product has an outstanding feel when used and is not water-repellent. DETAILED DESCRIPTION The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the protection scope of the present invention.

[0018] The purity of DMC used in the embodiment and comparative example 1 is >= 99.5%, and the volatile content is < 1%.

[0019] Example 1 (1) DMC (dimethylcyclosiloxane mixture), silane coupling agent and tetramethylammonium hydroxide were added into a three-necked flask equipped with an electric stirrer, a thermometer and a condenser in a mass ratio of 8:0.5:0.2, stirred for 15 minutes and heated to 120°C under a nitrogen atmosphere. After the reaction, piperazine coupling agent was obtained. The linear body, piperazine coupling agent and tetramethylammonium hydroxide catalyst solid were added into a three-necked flask equipped with an electric stirrer, a thermometer and a condenser in a mass ratio of 90:5.2:0.04, stirred for 15 minutes and heated to 75°C under a nitrogen atmosphere. The mixture was heated to 120°C and kept at a vacuum of 98KPa for 3 hours. The mixture was then heated to 140°C and kept at this temperature for 1.5 hours to decompose the tetramethylammonium hydroxide catalyst. Finally, the low boiling point was removed by vacuum distillation at 150°C. 1% citric acid was added to obtain a colorless, transparent and viscous product, which was a piperazine polysiloxane with a viscosity of about 60,000 CP. Piperazine polysiloxane and epoxy polyether (industrial product, purchased from Guangdong Nanhui New Materials Co., Ltd. for small-scale test) were added into a flask in an equimolar mass ratio, 30wt.% of the total amount of reactants was added as butyl ether as solvent, the temperature was raised to 75°C, and the reaction was carried out for 3h to obtain polyether block piperazine silicone oil; (2) Weigh 0.15 g of sodium dodecylbenzene sulfonate and add it to 84.76 g of water. After mechanical stirring to mix evenly, add 3 g of methyl methacrylate and 7 g of ethyl methacrylate to the solution. After mechanical stirring to mix evenly, put it into a water bath and pass N2 for 15 minutes. After heating to 90°C, dissolve 0.08 g of potassium persulfate in 5 g of water and add it to the above reaction mixture. After reacting for 2 hours, keep the temperature for 45 minutes to obtain a hard latex particle solution product 1 with a cross-linked structure and a solid content of 10%; (3) Weigh 1g of sodium dodecylbenzene sulfonate and add it to 83.94g of water. After mechanical stirring and mixing, add 1.4g of isooctyl acrylate and 3g of polyether block piperazine silicone oil mixture to the solution, and then add 0.6g of emulsifiers XL-40 and XL-90 in the same mass ratio; after mechanical stirring, put it into a water bath and pass N2 for 15min. After heating to 90°C, dissolve 0.06g of potassium persulfate in 5g of water and add it to the above reaction mixture. After reacting for 1.5h, keep warm for 45min to obtain a polyether block piperazine silicone oil-soft latex particle emulsion product 2 with a solid content of 10%; (4) Mix product 1 and product 2 to obtain a multi-layer darkening agent.

[0020] Example 2 The method is based on Example 1, except that the mass ratio of DMC, silane coupling agent and tetramethylammonium hydroxide is 10:0.9:0.3, and the rest is the same as Example 1.

[0021] Example 3 The method is based on Example 1, except that the mass ratio of DMC, silane coupling agent and tetramethylammonium hydroxide is 12:1:0.5, and the others are the same as Example 1.

[0022] Example 4 Example 4 Based on Example 2, polyether block piperazine silicone oil was obtained for subsequent experiments.

[0023] (1) Weigh 0.5 g of decapryl phenyl glycoside and add it to 74.78 g of water. After mechanical stirring and mixing, add 12 g of methyl methacrylate and 8 g of divinylbenzene to the solution. After mechanical stirring, put it into a water bath and pass nitrogen for 15 min. After heating to 90°C, dissolve 0.06 g of potassium persulfate in 5 g of water and add it to the above reaction mixture. After reacting for 2 h, keep the temperature for 45 min to obtain a hard latex particle solution product 3 with a cross-linked structure, with a solid content of 20%; (2) Weigh 2.5 g of decaprylyl phenyl glycoside and add it to 72.94 g of water. After mechanical stirring and mixing, add 8 g of isooctyl acrylate and 10 g of polyether block piperazine silicone oil mixture to the solution, and then add 2 g of emulsifiers XP30, XP50, XP70 and XP90 of the same mass ratio. After mechanical stirring, put it into a water bath and pass N2 for 15 minutes. After heating to 90°C, dissolve 0.06 g of potassium persulfate in 5 g of water and add it to the above reaction mixture. After reacting for 1.5 hours, keep warm for 45 minutes to obtain a polyether block piperazine silicone oil-soft latex particle emulsion product 4 with a solid content of 20%; (3) Mix product 3 and product 4 to obtain a multi-layer darkening agent.

[0024] Example 5 Example 5 Based on Example 2, polyether block piperazine silicone oil was obtained for subsequent experiments.

[0025] (1) Weigh 0.06 g of sodium dodecylbenzene sulfonate and 0.14 g of decapryl phenyl glycoside and add them to 69.88 g of water. After mechanical stirring and mixing, add 6 g of methyl methacrylate and 4 g of ethyl methacrylate to the solution. After mechanical stirring, put it into a water bath and pass N2 for 15 minutes. After heating to 90°C, dissolve 0.08 g of potassium persulfate in 5 g of water and add it to the above reaction mixture. After reacting for 2 hours, keep the temperature for 45 minutes to obtain a hard latex particle solution product 5 with a cross-linked structure, with a solid content of 25%; (2) Weigh 0.2g of sodium dodecylbenzene sulfonate and add it to 69.72g of water. After mechanical stirring and mixing, add 10g of methyl acrylate and 15g of polyether block piperazine silicone oil mixture to the solution, and then add 3g of emulsifiers AE0-3 and AE0-9 of the same mass ratio. After mechanical stirring, put it into a water bath and pass N2 for 15min. After heating to 90°C, dissolve 0.08g of potassium persulfate in 5g of water and add it to the above reaction mixture. After reacting for 1.5h, keep warm for 45min to obtain a polyether block piperazine silicone oil-soft latex particle emulsion product 6 with a solid content of 25%; (3) Mix product 5 and product 6 to obtain a multi-layer darkening agent.

[0026] Example 6 The method is based on Example 4, except that in Example 4, the silane coupling agent is directly converted into polyether block piperazine silicone oil without the treatment of step (1). The other steps are the same as in Example 4.

[0027] Comparative Example 1 The present invention is based on Example 4, except that the polyether block piperazine silicone oil is not included, and the other contents are the same as Example 4.

[0028] Comparative Example 2 The present invention is based on Example 4, except that the hard latex particle solution is not included, and the rest is the same as Example 4.

[0029] Comparative Example 3 The method is based on Example 4, except that in Example 4, the polyether block piperazine silicone oil and the hard latex particle solution are directly mixed without the treatment of step (2). The rest is the same as in Example 4.

[0030] Comparative Example 4 Based on Example 4, 10g of polyether block piperazine silicone oil was added with 2g of emulsifiers XP30, XP50, XP70 and XP90 in the same mass ratio; after mechanical stirring, a polyether block piperazine silicone oil emulsion with a solid content of 20% was obtained; the rest was the same as Example 4.

[0031] Application Example 1 (using the product in Example 2): 0.3 g of the hard latex particle aqueous dispersion in Example 2 and 2.7 g of the polyether block piperazine silicone oil-soft latex particle emulsion in Example 2 were weighed to prepare an emulsion mixture, and the mixture was dissolved in water to prepare a 30 mL solution. First, the polyester fabric was immersed in the emulsion finishing liquid, and the polyester fabric was finished by a one-immersion-one-rolling method, with a rolling rate of 70%. It was baked at 185° C. for 90 seconds to obtain the final finished polyester fabric 1.

[0032] Application Example 2 (using the product in Example 4) 0.75 g of the hard latex particle aqueous dispersion in Example 4 and 2.25 g of the polyether block piperazine silicone oil-soft latex particle emulsion in Example 4 were weighed to prepare an emulsion mixture, and the mixture was dissolved in water to prepare a 30 mL solution. Other conditions were the same as those in Example 1.

[0033] Application Example 3 (using the product in Example 6) 1.5 g of the hard latex particle aqueous dispersion in Example 6 and 1.5 g of the polyether block piperazine silicone oil-soft latex particle emulsion in Example 6 were weighed to prepare an emulsion mixture, and the mixture was dissolved in water to prepare 30 mL of an emulsion finishing liquid. Others were the same as those in Example 1.

[0034] Comparative application examples: Application Example 4 (using the product in Comparative Example 1) Based on Comparative Example 1, the difference is that Product 4 is a soft latex particle emulsion, and the rest is the same as Comparative Example 1.

[0035] Application Example 5 (using the product in Comparative Example 2) It is based on Comparative Example 2, except that the hard latex particle aqueous dispersion is not included, and the other aspects are the same as those of Comparative Example 1.

[0036] Application Example 6 (using the product in Comparative Example 3) The difference between Example 4 and Comparative Example 3 is that the polyether block piperazine silicone oil and the product 3 are directly mixed without the treatment of step (2), and the other aspects are the same as those of Comparative Example 1.

[0037] Application Example 7 (using the product in Comparative Example 4) The same as Comparative Example 4. Others are the same as Application Example 1.

[0038] The following evaluation items use equipment evaluation standards comparison examples to illustrate 1. Hydrophilicity: Use a standard dropper to drop a drop of water from a height of 15 cm from the fabric to the horizontally spread fabric surface, and measure the time it takes for the water to completely penetrate the fabric surface.

[0039] 2. Darkening rate: The K / S value of the fabric before and after darkening is measured by a colorimeter to calculate. The K / S value of the fabric before darkening is A, and the K / S value of the fabric after darkening is B. The darkening rate is (BA) / A×100%.

[0040] 3. Color difference: Use a computer colorimeter to test the ΔL*, Δa*, Δb*, and ΔE of the fabric before and after darkening, where ΔL* is the lightness difference, Δa* is the red-green light difference, Δb* is the yellow-blue light difference, and ΔE is the total color difference. ΔE is calculated using the following formula: ΔE = [(ΔL*)2 + (Δa*)2 + (Δb*)2]1 / 2. The larger the ΔE value, the greater the color difference.

[0041] 3. Hand feel: Touch the finished fabrics and rate them in groups of 10. Rating the printed fabrics according to different hand feels. The specific evaluation method is: Rating the hand feel from the two aspects of softness and smoothness, divided into 5 levels, 1 is the worst, the fabric feels hard and has poor smoothness. 5 is the best, the fabric feels soft and smooth.

[0042] 4. Brightness: Five senior experts in the industry jointly score the brightness of the treated fabrics. The brightness is divided into 1, 2, 3, 4, and 5 levels. The higher the level, the better.

[0043] 5. Washability After washing the fabric 100 times, observe the color of the fabric. The evaluation method is: if the color of the fabric remains more than 96% of that before washing, it means the fabric has good washability; if the color of the fabric remains 80-95% of that before washing, it means the fabric has good washability; if the color of the fabric remains less than 80% of that before washing, it means the fabric has poor washability.

[0044] 4. Abrasion color fastness test: Test the finished fabric in accordance with GB / T3920-2008 "Textiles - Color fastness - Abrasion color fastness".

[0045] Table 1 Results of performance tests

[0046] Note: From the above data in Table 1, it can be seen that the darkening agent provided by the present invention has an excellent darkening effect on fabrics and has little effect on the original color, feel, scrub fastness and washing fastness of the fabric.

[0047] The present invention prepares a hard latex particle water dispersion and a polyether block piperazine silicone oil-soft latex particle emulsion into an emulsion mixture, and the mixed emulsion product has a certain hydrophilicity and good stability, and at the same time has the effect of increasing the depth and brightness. Among them, the effect of 1:3 is the best.

[0048] The technical solution of the present invention is explained through the above embodiments, but the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by technicians in the relevant field based on the present invention, or equivalent replacement of the materials selected by the present invention, etc., fall within the scope of protection of the patent.

Claims

1. A method for preparing a multi-layered darkening agent, characterized in that: The preparation method comprises the following steps: (1) Preparation of polyether block piperazine silicone oil: first, a silane coupling agent, DMC and tetramethylammonium hydroxide are uniformly mixed, and the temperature is raised to react to obtain a piperazine coupling agent; then, a linear body, a piperazine coupling agent and a tetramethylammonium hydroxide catalyst are uniformly mixed, nitrogen is introduced to deoxygenate, the temperature is raised, a vacuum is applied, the temperature is raised to react, the temperature is raised again, the temperature is kept, the acid is added after cooling, and the material is stirred to obtain piperazine polysiloxane; then, the piperazine polysiloxane is reacted with an epoxy-terminated polyether to prepare a polyether block piperazine silicone oil; (2) Preparation of polyether block piperazine silicone oil-soft latex particle emulsion: fully stir an emulsifier and water to form an emulsifier aqueous solution, mix the monomer 1 for forming soft latex particles with the polyether block piperazine silicone oil obtained in step (1), pass nitrogen to deoxygenate, heat to react, cool to room temperature after the reaction is completed; then add to a mixture of the emulsifier aqueous solution and the co-solvent in equal mass ratios, add an initiator and water, react and continue to keep warm to obtain a polyether block piperazine silicone oil-soft latex particle emulsion; (3) Preparation of hard latex particle aqueous dispersion: fully stir the emulsifier and water, add monomer 2 and a cross-linking agent for forming hard latex particles into the emulsifier aqueous solution, pass nitrogen to remove oxygen, and after the temperature reaction is completed, add an initiator and water, react and continue to keep the temperature to obtain a hard latex particle aqueous dispersion; (4) Preparation of a multilayer structured darkening agent: The polyether block piperazine silicone oil-soft latex particle emulsion obtained in step (2) is mixed with the hard latex particle aqueous dispersion obtained in step (3) to obtain a multilayer structured darkening agent.

2. The method for preparing the multi-layered darkening agent according to claim 1, characterized in that: In the step (1), the silane coupling agent is 3-piperazinepropylmethyldimethoxysilane; the linear phase is dihydroxylated polydimethylsiloxane with a viscosity of 60-80 cst; the purity of DMC is greater than or equal to 99.5%, and the volatile content is less than 1%; the mass ratio of DMC, silane coupling agent, and tetramethylammonium hydroxide is (8-12): (0.5-1): (0.2-0.5); the mass ratio of the linear phase, piperazine coupling agent, and tetramethylammonium hydroxide is (85-95): (4-5.5): (0.02-0.06).

3. The method for preparing the multi-layered darkening agent according to claim 2, characterized in that: In the step (1), the preparation of polyether block piperazine silicone oil is as follows: first, a silane coupling agent, DMC and tetramethylammonium hydroxide are uniformly mixed, and the temperature is raised to 120-130°C to serve as a piperazine coupling agent; then, a linear body, a piperazine coupling agent and a tetramethylammonium hydroxide catalyst are uniformly mixed, nitrogen is passed through to deoxygenate for 5-15 minutes, the temperature is raised to 72-78°C, a vacuum is applied, the temperature is further raised to 110-125°C for insulation reaction for 2-4 hours, the temperature is then raised to 130-150°C for insulation reaction for 1-2 hours, the temperature is then raised to 130-150°C for insulation reaction, the temperature is then raised to 130-150°C for 1-2 hours, the temperature is cooled, an acid is added, and the material is stirred for 25-35 minutes to obtain piperazine polysiloxane; then, the silicone oil is reacted with an epoxy-terminated polyether in an equimolar mass ratio and added to a container, 25-35wt.% of the total amount of the reactants is added as a solvent, the temperature is raised to 70-80°C, and the reaction is performed for 2-4 hours to prepare a polyether block piperazine silicone oil.

4. The method for preparing the multi-layered darkening agent according to claim 1, characterized in that: In the step (2), the following raw materials are used in parts by weight: 60-95 parts of water; 3-12 parts of polyether block piperazine silicone oil; Emulsifier 0.01-5 parts; 1 to 6 parts of co-solvent; Monomer 1 10-45 parts; Initiator 0.001~0.9 parts.

5. The method for preparing the multi-layer structure deepening agent according to claim 4, characterized in that: The emulsifier is a mixture of one or more of sodium dodecyl sulfate, sodium alkyl sulfonate, sodium dodecylbenzene sulfonate and isooctylphenyl glycoside; the cosolvent is isomeric fatty decyl alcohol polyoxyethylene ether or fatty alcohol polyoxyethylene ether.

6. The method for preparing the multi-layer structure deepening agent according to claim 4, characterized in that: In step (2), the monomer 1 is a mixture of one or more of methyl acrylate, ethyl acrylate, butyl acrylate, isooctyl acrylate, and isobornyl acrylate; and the initiator is a mixture of one or more of potassium persulfate and ammonium persulfate.

7. The method for preparing the multi-layer structure deepening agent according to claim 1, characterized in that: In step (2), nitrogen is passed to deoxygenate for 10 to 20 minutes, the temperature is raised to 85 to 95°C, and after the reaction is completed, the mixture is cooled to room temperature and then added to the emulsifier aqueous solution, an initiator and water are added, and the reaction is continued for 2 to 3 hours and the temperature is kept constant for 40 to 55 minutes.

8. The method for preparing the multi-layer structure deepening agent according to claim 1, characterized in that: In step (3), the following raw materials are used in parts by weight: 60-93 parts of water; Emulsifier 0.01-3 parts; Monomer 2 10-30 parts; 1 to 6 parts of cross-linking agent; Initiator 0.001-0.9 parts; The monomer 2 is one or a mixture of methyl methacrylate and ethyl methacrylate; the emulsifier is one or a mixture of sodium dodecyl sulfate, sodium alkyl sulfonate, sodium dodecylbenzene sulfonate, isooctylphenyl glycoside; the initiator is one or a mixture of potassium persulfate and ammonium persulfate; The cross-linking agent is one of divinylbenzene and ethylene glycol dimethacrylate; In the step (4), the mass ratio of the hard latex particle aqueous dispersion: the polyether block piperazine silicone oil-soft latex particle emulsion is 1:(1-9).

9. A multi-layered darkening agent prepared according to the preparation method according to any one of claims 1 to 8.

10. Use of the multi-layer structure darkening agent according to claim 9 in darkening finishing of polyester fabrics.

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