CN102286234B - Preparation method of modified acrylic resin leather coating material of carbon nano tubes (CNTs) in situ - Google Patents

Abstract

The invention provides a method for preparing carbon nanotubes (CNTs) in-situ modified acrylic resin leather coating materials, wherein single-wall or multi-wall carbon nanotubes are treated with a strong acid solution to remove impurities in the carbon nanotubes and obtain carboxylation CNTs; react the carboxylated CNTs with thionyl chloride and acrylamide successively to obtain acrylamide-grafted CNTs, and finally combine the acrylamide-grafted CNTs with acrylic monomers under the action of emulsifier and initiator Emulsion polymerization takes place to generate carbon nanotube modified acrylic resin leather finishing materials in situ. The invention utilizes the extremely high surface ratio of the carbon nanotube to enhance and toughen the composite material, and the extremely high length-to-diameter ratio to modify the acrylic resin leather finishing material during the preparation process of the finishing material. The invention has the advantages of simple process, environmental protection and low cost, and is suitable for industrialized production. The comprehensive properties of the obtained functionalized carbon nanotube modified acrylic resin leather finishing emulsion coating film have obvious improvement in hiding power, color change resistance and aging resistance, abrasion resistance, tensile strength, heat and cold resistance, and flame retardancy. , The quality of leather products has improved significantly.

Description

A kind of preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material

technical field

The invention belongs to the field of leather chemical industry, in particular to a method for preparing a carbon nanotube in-situ modified acrylic resin leather finishing material.

Background technique

As a leather surface coating material, leather finishing agent can significantly improve the performance of leather, expand the application range of leather and improve the grade of leather products. Acrylic resin leather finishing agents have a series of advantages, such as good film-forming properties, strong adhesion, simple production process and low cost. They are favored by the leather industry and have developed rapidly. However, ordinary acrylic resin emulsion coatings have disadvantages such as "hot stickiness, cold brittleness" and insolvent resistance, so their use is limited. In order to overcome these shortcomings, it needs to be further studied and modified to meet newer requirements.

In recent years, most researchers at home and abroad have focused on adjusting the types and proportions of monomers and introducing organic molecules or polymers such as organic silicon and organic fluorine to modify acrylic resins. However, it is still difficult to meet many practical properties required for finished leather, and it is impossible to endow leather with some special functions.

Introducing nanoparticles into the leather coating and organically combining them with film-forming agents can improve the overall performance of the coating, improve the strength, abrasion resistance, aging resistance and weather resistance of the polymer, and increase the additional properties of the finished leather. Value is an important direction for the development of leather finishing agents and a hot spot in the field of finishing product research and development. As a one-dimensional nanomaterial, carbon nanotubes (CNTs) are light in weight, perfectly connected in a hexagonal structure, and have the characteristics of large specific surface area, high mechanical strength, high electrical conductivity, good thermal conductivity and heat resistance. Applying CNTs to the modification of acrylic resin coating agents, taking advantage of the characteristics of CNTs and the strengthening and toughening properties of nanomaterials, can significantly improve the covering power of the coating, improve the tensile strength, elongation at break, wear resistance, and flame retardancy physical and mechanical properties. It has important application prospects for improving the functionality of leather and broadening the application range of leather. There are no relevant reports on the application and research of carbon nanotubes in leather finishing agents.

Contents of the invention

The invention provides a method for preparing acrylic resin leather coating materials modified in situ by carbon nanotubes. When the acrylic resin is modified by in situ emulsion polymerization of carbon nanotubes, the abrasion resistance, tensile strength and fracture of the resin can be significantly improved. Physical and mechanical properties such as elongation.

In order to achieve the above object, the preparation method of carbon nanotube in situ modified acrylic resin leather finishing material of the present invention comprises the following steps:

Step 1: After mixing single-walled or multi-walled carbon nanotubes with an acidic solution at a volume ratio of 0.025:1, ultrasonic treatment is prepared to prepare a suspension, which is left to soak for 24-48 hours, then heated and condensed to reflux, and finally washed repeatedly until The pH is neutral, and centrifuged to obtain carboxylated carbon nanotubes, wherein the acidic solution refers to a mixed acid formed by concentrated sulfuric acid and concentrated nitric acid in a volume ratio of (1-3): 1;

Step 2: reacting the above-mentioned carboxylated carbon nanotubes with excess thionyl chloride and acrylamide successively to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Polymerize the modified carbon nanotubes grafted with acrylamide obtained in Step 2 and the acrylic monomer with a double bond functional group under the action of distilled water, emulsifier sodium lauryl sulfate and initiator ammonium persulfate In-situ generation of carbon nanotube-modified acrylic resin-based leather finishing materials.

Compared with the prior art, the preparation method of the carbon nanotube modified acrylic resin leather finishing material of the present invention has at least the following advantages: when the carbon nanotube in-situ emulsion polymerization method modifies the acrylic resin, the abrasion resistance of the resin can be significantly improved , tensile strength, elongation at break and other physical and mechanical properties. Among them, adding all the carbon nanotubes at one time can significantly increase the tensile strength of the resin, and adding the carbon nanotubes and monomers after mixing can significantly increase the elongation at break of the resin.

Detailed ways

Embodiment one:

Step 1: Purification and modification of carbon nanotubes: first, mix sulfuric acid with a mass concentration of 95% and nitric acid with a mass concentration of 68% at a volume ratio of 1:1 to form a mixed acid solution; then, mix the carbon nanotubes Mix with the mixed acid solution at a mass ratio of 0.025:1, and then ultrasonically treat it to form a stable suspension. After soaking for 24 hours, heat, condense and reflux at 110°C for 1 hour, and finally wash and centrifuge repeatedly until the pH value is 7 to remove carbon. Impurities in nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: Stir and reflux the carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride at 60°C for 24 hours, then distill at 85°C-90°C for 3-4 hours, and vacuum dry for 6-7 Hours, the carbon nanotubes of acid chlorination are obtained; then, after dissolving the acrylamide and the carbon nanotubes of acid chloride with organic solvent (such as: tetrahydrofuran) respectively, acrylamide is added to the constant pressure dropping funnel, and the carbon nanotubes of acid chloride Add the tube into the three-necked flask, then add excess acrylamide to the acyl chlorided carbon nanotubes at 60-65°C, slowly add dropwise for 1-1.5 hours, then continue the reaction for 24 hours, then at 85°C-90 Distill at ℃ for 3-4 hours, finally wash with water, centrifuge and dry in vacuum to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Take monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, a total of 100 parts, the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: absolute ethanol is 1 : (2-6): (3-6): (0.3-0.6): (3-6), take the ammonium persulfate of 0.3% of the total mass of the monomer and absolute ethanol as the initiator, and weigh the total mass of the monomer 2% by mass of sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of 0.01% of the total mass of monomers are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then Add ethanol, and then dissolve the acrylamide-grafted carbon nanotubes in distilled water and emulsifier, ultrasonicate for 5 minutes, then add them into a reactor containing one-third of the monomer, heat and stir, and set the stirring speed to 300r/min , when the temperature rises to 70°C, add a quarter of the initiator dissolved in distilled water, and at the same time, use a constant pressure dropping funnel to drop the remaining two-thirds of the monomer and the remaining three-quarters of the initiator The initiator solution should be dropped in about 1 hour. Among them, the initiator should be added slightly later than the monomer. After all the drops are completed, keep the temperature at about 80°C for 1 hour, then cool down to 60°C, add an appropriate amount of ammonia water to neutralize, and adjust pH = 6-7, continue to stir for 0.5h, cool to room temperature, pour out, and filter to obtain carbon nanotube-modified water-based acrylic resin emulsion.

Embodiment two:

Step 1: Purification and modification of carbon nanotubes: first, mix sulfuric acid with a mass concentration of 95% and nitric acid with a mass concentration of 68% at a volume ratio of 2:1 to form a mixed acid solution; then, mix the carbon nanotubes Mix with the mixed acid solution at a mass ratio of 0.025:1, and then ultrasonically treat it to form a stable suspension. After soaking for 35 hours, heat, condense and reflux at 115°C for 1 hour, and finally wash and centrifuge repeatedly until the pH value is 7 to remove Impurities in carbon nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: Stir and reflux the carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride at 65°C for 30 hours, then distill at 85°C-90°C for 4-5 hours, and vacuum dry for 7-8 hours Hours, the carbon nanotubes of acid chlorination are obtained; then, after dissolving the acrylamide and the carbon nanotubes of acid chloride with organic solvent (such as: tetrahydrofuran) respectively, acrylamide is added to the constant pressure dropping funnel, and the carbon nanotubes of acid chloride Add the tube into the three-necked flask, then add excess acrylamide to the acyl chlorided carbon nanotubes at 60-65°C, slowly add dropwise for 1-1.5 hours, then continue the reaction for 24 hours, then at 85°C-90 Distill at ℃ for 4-5 hours, finally wash with water, centrifuge and dry in vacuum to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Take monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, a total of 100 parts, the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: absolute ethanol is 1 : (4-6): (4-6): (0.4-0.6): (4-6), take by weighing 0.4% initiator of total mass of monomer and dehydrated alcohol, take by weighing 3% of total mass of monomer Sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of 0.02% of the total monomer mass are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then Add ethanol, and then dissolve the acrylamide-grafted carbon nanotubes in distilled water and emulsifier, ultrasonicate for 5 minutes, and then add them into a reactor containing one-third of the monomer, heat and stir, and set the stirring speed to 400r/min , when the temperature rises to 75°C, add a quarter of the initiator dissolved in distilled water, and at the same time, use a constant pressure dropping funnel to drop the remaining two-thirds of the monomer and the remaining three-quarters of the initiator The initiator solution should be dropped in about 1 hour. Among them, the initiator should be added slightly later than the monomer. After all the drops are completed, keep the temperature at about 80°C for 1 hour, then cool down to 60°C, add an appropriate amount of ammonia water to neutralize, and adjust pH = 6-7, continue to stir for 0.5h, cool to room temperature, pour out, and filter to obtain carbon nanotube-modified water-based acrylic resin emulsion.

Embodiment three:

Step 1: Purification and modification of carbon nanotubes: first, mix sulfuric acid with a mass concentration of 95% and nitric acid with a mass concentration of 68% in a volume ratio of 3:1 to form a mixed acid solution; then, mix the carbon nanotubes Mix with the mixed acid solution at a mass ratio of 0.025:1, then ultrasonically treat to form a stable suspension, soak for 48 hours, heat and condense at 120°C for reflux for 1 hour, and finally wash and centrifuge repeatedly until the pH value is 7 to remove Impurities in carbon nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: Stir and reflux the carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride at 70°C for 36 hours, then distill at 85°C-90°C for 5-6 hours, and dry in vacuum for 8 hours. Obtain acyl chlorinated carbon nanotubes; then, after dissolving acrylamide and acyl chlorinated carbon nanotubes with an organic solvent (such as tetrahydrofuran) respectively, acrylamide is added to a constant pressure dropping funnel, and acyl chlorinated carbon nanotubes are added into a three-necked flask, and then add excess acrylamide to the acid-chlorinated carbon nanotubes at 60-65°C, drop it slowly for 1-1.5 hours, and then continue the reaction for 24 hours, at 85°C-90°C Distill for 5-6 hours, finally wash with water, centrifuge and dry in vacuum to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Take monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, a total of 100 parts, the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: absolute ethanol is 1 : (5-6): (5-6): (0.4-0.6): (4-6), take the ammonium persulfate of 0.5% of the total mass of the monomer and absolute ethanol as the initiator, and weigh the total mass of the monomer 4% sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of the monomer total mass of 0.04% are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then Add ethanol, and then dissolve the acrylamide-grafted carbon nanotubes in distilled water and emulsifier, ultrasonicate for 5 minutes, and then add them to a reactor containing one-third of the monomer, heat and stir, and set the stirring speed to 500r/min , when the temperature rises to 70-80 ° C, add a quarter of the initiator dissolved in distilled water, and at the same time, use a constant pressure dropping funnel to drop the remaining two-thirds of the monomer and the remaining one-quarter Three initiator solutions, about 1 hour to finish dripping, among them, the initiator should be added slightly later than the monomer. After all the drops are completed, keep the temperature at about 80°C for 1 hour, then cool down to 60°C, add an appropriate amount of ammonia water to neutralize, And adjust the pH=6-7, continue to stir for 0.5h, cool to room temperature, pour out, filter, and obtain the carbon nanotube modified water-based acrylic resin emulsion.

Embodiment four:

Step 1: Purification and modification of carbon nanotubes: first, mix 96% sulfuric acid with a mass concentration of 67% nitric acid in a volume ratio of 1:1 to form a mixed acid solution; then, take a relative mixed acid mass of 0.025 Add carbon nanotubes twice as many times into the mixed acid solution, and ultrasonically make it form a stable suspension; soak for 24 hours, then heat and condense at 110°C for reflux for 1 hour, and then repeatedly wash with water and centrifuge until the pH value is 6 to remove Impurities in carbon nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: The carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride were stirred and refluxed at 60°C-70°C for 24 hours, then distilled at 85°C-90°C for 3-4 hours, and vacuum-dried for 6 -7 hours to obtain acid-chlorinated carbon nanotubes; then, after dissolving acrylamide and acid-chlorinated carbon nanotubes with an organic solvent (such as tetrahydrofuran) respectively, carbon nanotubes and excess acrylamide were added to a three-necked flask And in the constant pressure dropping funnel, drop slowly at 60-65°C for 1-1.5 hours, then continue to react for 24 hours, distill at 85°C-90°C for 3-4 hours, finally wash with water, centrifuge, vacuum drying to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Get a total of 100 parts of monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, and the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: dehydrated alcohol is 1: (2-6): (3-6): (0.3-0.6): (3-6); take by weighing 0.3% ammonium persulfate of the total mass of the monomer and absolute ethanol as the initiator, and weigh the total mass of the monomer 2% sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of 0.01% of the total mass of monomers are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then add Dissolve the emulsifier sodium lauryl sulfate in distilled water and ethanol, heat and stir, and set the stirring speed at 300-500r/min. When the temperature rises to 70-80°C, add a quarter of the dissolved distilled water to initiate The acrylamide-grafted carbon nanotubes and the remaining two-thirds of the basic monomers were ultrasonically added to the reactor with a constant pressure dropping funnel for 5 minutes. After the monomers were started to be added, slowly and evenly Add the remaining three-quarters of the initiator to the constant pressure dropping funnel, and finish dropping in about 1 hour. The initiator should be added later than the monomer. After all the dropping is completed, keep the temperature at about 80°C for 1 hour, and then cool down to 60°C. ℃, add an appropriate amount of ammonia water for neutralization, adjust the pH to 6-7, continue to stir for 0.5 h, cool to room temperature, pour out, and filter to obtain a carbon nanotube-modified water-based acrylic resin emulsion.

Embodiment five

Step 1: Purification and modification of carbon nanotubes: first, mix sulfuric acid with a mass concentration of 96% and nitric acid with a mass concentration of 68% in a volume ratio of 2:1 to form a mixed acid solution; then, take a relative mixed acid mass of 0.025 Add carbon nanotubes twice as many times into the mixed acid solution, and ultrasonically make it form a stable suspension; then soak for 40 hours, then heat, condense and reflux at 115°C for 1 hour, then repeatedly wash with water and centrifuge until the pH value is 6, to remove Impurities in carbon nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: The carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride were stirred and refluxed at 60°C-70°C for 32 hours, then distilled at 85°C-90°C for 5-6 hours, and vacuum-dried for 7 -8 hours, the carbon nanotubes of acyl chlorination were obtained; then, after dissolving the acrylamide and the carbon nanotubes of acyl chlorination with an organic solvent (such as: tetrahydrofuran) respectively, the carbon nanotubes and excess acrylamide were respectively added to a three-necked flask And in the constant pressure dropping funnel, drop slowly at 60-65°C for 1-1.5 hours, then continue to react for 24 hours, distill at 85°C-90°C for 4-5 hours, finally wash with water, centrifuge, vacuum drying to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Get a total of 100 parts of monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, and the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: dehydrated alcohol is 1: (3-6): (4-6): (0.4-0.6): (5-6); take the ammonium persulfate of 0.4% of the total mass of monomer and absolute ethanol as initiator, and take the total mass of monomer 3% sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of 0.03% of the total monomer mass are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then add Dissolve the emulsifier sodium lauryl sulfate in distilled water and ethanol, heat and stir, the stirring speed is set to 350r/min, when the temperature rises to 70-80°C, add a quarter of the initiator dissolved in distilled water, The acrylamide-grafted carbon nanotubes and the remaining two-thirds of the basic monomers were sonicated for 5 minutes and then added dropwise to the reactor with a constant pressure dropping funnel. Add the remaining three-quarters of the initiator dropwise through the funnel, and finish dropping in about 1 hour. The initiator should be added slightly later than the monomer. After all the dropping is completed, keep the temperature at about 80°C for 1 hour, then cool down to 60°C, and add an appropriate amount neutralized with ammonia water, adjusted to pH=6-7, continued to stir for 0.5 h, cooled to room temperature, poured out, and filtered to obtain a carbon nanotube-modified water-based acrylic resin emulsion.

Embodiment six

Step 1: Purification and modification of carbon nanotubes: first, mix sulfuric acid with a mass concentration of 96% and nitric acid with a mass concentration of 68% in a volume ratio of 3:1 to form a mixed acid solution; then, take a relative mixed acid mass of 0.025 Add carbon nanotubes twice as many times into the mixed acid solution, and ultrasonically make it form a stable suspension; then soak for 48 hours, then heat, condense and reflux at 120°C for 1 hour, then repeatedly wash with water and centrifuge until the pH value is 6, to remove Impurities in carbon nanotubes, and active reactive groups on the surface to obtain carboxylated carbon nanotubes;

Step 2: The carboxylated carbon nanotubes obtained in Step 1 and excess thionyl chloride were stirred and refluxed at 60°C-70°C for 36 hours, then distilled at 85°C-90°C for 5-6 hours, and vacuum-dried for 7 -8 hours, the carbon nanotubes of acyl chlorination were obtained; then, after dissolving the acrylamide and the carbon nanotubes of acyl chlorination with an organic solvent (such as: tetrahydrofuran) respectively, the carbon nanotubes and excess acrylamide were respectively added to a three-necked flask And in the constant pressure dropping funnel, slowly add dropwise at 60-65°C for 1-1.5 hours, then continue to react for 24 hours, distill at 85°C-90°C for 5-6 hours, finally wash with water, centrifuge, vacuum drying to obtain modified carbon nanotubes grafted with acrylamide;

Step 3: Get a total of 100 parts of monomers and cosolvent dehydrated alcohols used for emulsion synthesis of acrylic resins, and the mass ratio of monomers used: acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: dehydrated alcohol is 1: (5-6): (4-6): (0.5-0.6): (4-6); take by weighing the ammonium persulfate of 0.5% of the total mass of the monomer and absolute ethanol as the initiator, and weigh the total mass of the monomer 4% sodium lauryl sulfate is used as an emulsifier for the reaction, and the acrylamide-grafted carbon nanotubes obtained in step 2 of 0.04% of the total monomer mass are weighed;

Step 4: Stir the basic monomers acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to the reactor equipped with a stirrer, reflux condenser, and thermometer, and then add The emulsifier sodium lauryl sulfate dissolved in distilled water and ethanol is heated and stirred, and the stirring speed is set to 500r/min. When the temperature rises to 70-80°C, add a quarter of the initiator dissolved in distilled water, The acrylamide-grafted carbon nanotubes and the remaining two-thirds of the basic monomers were ultrasonically added to the reactor with a constant pressure dropping funnel for 5 minutes. Add the remaining three-quarters of the initiator to the dropping funnel for about 1 hour. The initiator should be added later than the monomer. After all the addition is completed, keep the temperature at about 80°C for 1 hour, and then cool down to 60°C. Add an appropriate amount of ammonia water for neutralization, adjust the pH to 6-7, continue to stir for 0.5 h, cool to room temperature, pour out, and filter to obtain a carbon nanotube-modified water-based acrylic resin emulsion.

The repeated water washing and centrifugation described in step 1 of the above embodiment refers to first washing with water, then centrifugation, removing the supernatant and retaining the solid matter, then adding water to the solid matter for water washing, and then centrifuging Separation, removal of supernatant and retention of solids, and so on, until the pH reaches the specified requirements.

The above is only one embodiment of the present invention, not all or the only embodiment. Any equivalent transformation of the technical solution of the present invention adopted by those of ordinary skill in the art by reading the description of the present invention is the right of the present invention. covered by the requirements.

Claims (10)

1. a kind of preparation method of carbon nanotube in situ modification acrylic resin leather finishing material, its feature comprises the following steps: Step 1: After mixing single-walled or multi-walled carbon nanotubes with an acidic solution at a mass ratio of 0.025:1, ultrasonic treatment is used to prepare a suspension, which is left to soak for 24-48 hours, then heated and condensed to reflux, and finally washed repeatedly until The pH is neutral, and centrifuged to obtain carboxylated carbon nanotubes, wherein the acidic solution refers to a mixed acid formed by concentrated sulfuric acid and concentrated nitric acid in a volume ratio of (1-3):1; Step 2: reacting the carboxylated carbon nanotubes with excess thionyl chloride and acrylamide successively to obtain modified carbon nanotubes grafted with acrylamide; Step 3: Polymerize the modified carbon nanotubes grafted with acrylamide obtained in Step 2 and the acrylic monomer with a double bond functional group under the action of distilled water, emulsifier sodium lauryl sulfate and initiator ammonium persulfate Reactive in-situ generation of carbon nanotube-modified acrylic resin-based leather finishing materials. 2. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 1, is characterized in that: in step 3, the acrylic monomer of described double bond functional group is dissolved in anhydrous A mixture of acrylic acid, methyl methacrylate, butyl acrylate and acrylamide in ethanol, wherein the mass ratio of acrylic acid: methyl methacrylate: butyl acrylate: acrylamide: dehydrated alcohol is 1: (2- 6): (3-6): (0.3-0.6): (3-6). 3. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 2, is characterized in that: in step 3, the consumption of described emulsifier sodium lauryl sulfate is acrylic acid 2-4% of the total mass of monomers, the amount of the initiator ammonium persulfate is 0.3-0.5% of the total mass of acrylic monomers and absolute ethanol; the amount of acrylamide-modified carbon nanotubes is acrylic resin 0.01-0.04% of the total mass of the monomer, and the amount of distilled water is such that the solid content of the system formed by the acrylic monomer, absolute ethanol, emulsifier, initiator, distilled water, and acrylamide-modified carbon nanotubes is 20- 30%. 4. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 3, is characterized in that: in step 3, the concrete step of described polymerization reaction is: first acrylic monomer Stir acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, then add one-third of the amount into the reactor, then add absolute ethanol to the reactor, and then dissolve them in distilled water and emulsifier The acrylamide-grafted carbon nanotubes were ultrasonically treated and added to the aforementioned reactor, heated and stirred at a speed of 300-500r/min, and when the temperature rose to 70-80°C, dissolved in One quarter of the initiator in distilled water, at the same time, drop the remaining two thirds of the acrylic monomer and the remaining three quarters of the initiator solution with a constant pressure dropping funnel, wherein the initiator is slightly later than the acrylic acid After the monomers have been added dropwise, keep the temperature at 80°C for 1 hour, then cool down to 60°C, adjust the pH to 6-7, stir and cool to room temperature, and filter to obtain the carbon nanotube modified water-based acrylic resin emulsion. 5. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 3, it is characterized in that: in step 3, the concrete step of described polymerization reaction is: first acrylic monomer Stir acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, then add one-third of the amount into the reactor, and then add emulsifier sodium lauryl sulfate dissolved in distilled water and absolute ethanol , heating and stirring at a speed of 300-500r/min, when the temperature rises to 70-80°C, add a quarter of the initiator dissolved in distilled water, and then mix the acrylamide-grafted carbon nanotubes with the remaining third Two-thirds of the monomers are added dropwise to the reactor with a dropping funnel after ultrasonication for 5 minutes. When two-thirds of the monomers start to be added dropwise, add the remaining three-quarters of the initiator dropwise. After the monomers have been added dropwise, keep the temperature at 80°C for 1 hour, then cool down to 60°C, adjust the pH to 6~7, stir and cool to room temperature, and then filter to obtain the carbon nanotube modified water-based acrylic resin emulsion. 6. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 4 or 5, is characterized in that: described step 2 is specifically: first carboxylated carbon nanotube and excess Thionyl chloride was stirred and refluxed, then distilled and vacuum-dried to obtain acid-chlorinated carbon nanotubes, and then the excess acrylamide dissolved in tetrahydrofuran was slowly added dropwise to the acid-chlorinated carbon nanotubes dissolved in tetrahydrofuran, and the reaction produced Modified carbon nanotubes grafted with acrylamide. 7. A method for preparing a carbon nanotube in-situ modified acrylic resin leather finishing material, characterized in that: comprising the following steps: Step 1: After mixing the carbon nanotubes with the acidic solution at a mass ratio of 0.025:1, ultrasonically treat for 10-20 minutes to prepare a suspension, leave to soak for 24-48 hours, and then heat, condense and reflux at 110°C-120°C for 1 -2 hours, and finally repeated washing and separation until the pH is neutral to obtain carboxylated carbon nanotubes. The acidic solution refers to a mixed acid formed by concentrated sulfuric acid and concentrated nitric acid in a volume ratio of (1-3):1; Step 2: Stir and reflux the above-mentioned carboxylated carbon nanotubes and excess thionyl chloride at 60°C-70°C for 24-36 hours, then distill at 85°C-90°C for 3-6 hours, and vacuum dry for 6- Acyl chlorinated carbon nanotubes were obtained in 8 hours; then, the acrylamide and the acyl chlorinated carbon nanotubes were dissolved in tetrahydrofuran, an organic solvent, respectively, and then the excess acrylamide solution dissolved in the organic solvent was added dropwise to the dissolved In the acid-chlorinated carbon nanotubes in an organic solvent, slowly add dropwise for 1-1.5 hours, then continue to react for 24 hours, then distill at 85°C-90°C for 3-6 hours, finally wash with water, centrifuge, vacuum drying to obtain modified carbon nanotubes grafted with acrylamide; Step 3: According to the mass ratio of 1: (2-6): (3-6): (0.3-0.6): (3-6) take acrylic monomer acrylic acid, methyl methacrylate, butyl acrylate, propylene Amide and absolute ethanol; ammonium persulfate is used as the initiator, and the dosage is 0.3-0.5% of the total mass of acrylic monomer and absolute ethanol; sodium lauryl sulfate is used as the emulsifier of the reaction, and the dosage is acrylic 2-4% of the total mass of monomers, take the modified carbon nanotubes grafted with acrylamide obtained in step 2, the dosage is 0.01-0.04% of the total mass of acrylic monomers, take distilled water, and the dosage is to make the acrylic monomers , absolute ethanol, emulsifier, initiator, distilled water, and acrylamide-modified carbon nanotubes, the solid content of the system is 20-30%; Step 4: Stir the acrylic monomers prepared in Step 3: acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, take one-third of the amount and add it to a mixing tank equipped with a stirrer, reflux condenser, and thermometer. In the reactor, at the same time, the emulsifier sodium lauryl sulfate is dissolved in the mixed solution of distilled water and ethanol, and then, the dissolved sodium lauryl sulfate is added to the above-mentioned one-third basic monomer In the reactor, heat at a stirring speed of 300-500r/min. When the temperature rises to 70-80°C, pour a quarter of the initiator dissolved in distilled water, and then add acrylamide dropwise at the same time The grafted modified carbon nanotubes, the remaining two-thirds of the basic monomers and the remaining three-quarters of the initiator are dropped for 1 hour. After the drop is completed, keep the temperature at 80°C for 1 hour, then cool down to 60°C, and adjust When the pH is 6-7, continue to stir for 0.5h, cool to room temperature, pour out, and filter to obtain the carbon nanotube in-situ modified acrylic resin leather finishing material. 8. the preparation method of carbon nanotube in-situ modified acrylic resin leather finishing material as claimed in claim 7, is characterized in that: in described step 4, described initiator is slightly later than remaining 2/3 unit The body is added dropwise. 9 . The method for preparing acrylic resin leather finishing material modified in situ by carbon nanotubes according to claim 7 , characterized in that: in the step 4, adjusting pH=6-7 is achieved by adding ammonia water dropwise. 10. A method for preparing a carbon nanotube in-situ modified acrylic resin leather finishing material, characterized in that: comprising the following steps: Step 1: After mixing the carbon nanotubes with the acidic solution at a mass ratio of 0.025:1, ultrasonically treat for 10-20 minutes to prepare a suspension, leave to soak for 24-48 hours, and then heat, condense and reflux at 110°C-120°C for 1 -2 hours, and finally repeated washing and separation until the pH is neutral to obtain carboxylated carbon nanotubes. The acidic solution refers to a mixed acid formed by concentrated sulfuric acid and concentrated nitric acid in a volume ratio of (1-3):1; Step 2: Stir and reflux the above-mentioned carboxylated carbon nanotubes and excess thionyl chloride at 60°C-70°C for 24-36 hours, then distill at 85°C-90°C for 3-6 hours, and vacuum dry for 6- Acyl chlorinated carbon nanotubes were obtained in 8 hours; then, the acrylamide and the acyl chlorinated carbon nanotubes were dissolved in tetrahydrofuran, an organic solvent, respectively, and then the excess acrylamide dissolved in the organic solvent was added dropwise to the dissolved Slowly add dropwise to acid-chlorinated carbon nanotubes in an organic solvent for 1-1.5 hours, then continue to react for 24 hours, then distill at 85°C-90°C for 3-6 hours, finally wash with water, centrifuge, and vacuum dry , to obtain modified carbon nanotubes grafted with acrylamide; Step 3: According to the mass ratio of 1: (2-6): (3-6): (0.3-0.6): (3-6) take acrylic monomer acrylic acid, methyl methacrylate, butyl acrylate, propylene Amide and absolute ethanol; ammonium persulfate is used as the initiator, and the dosage is 0.3-0.5% of the total mass of acrylic monomer and absolute ethanol; sodium lauryl sulfate is used as the emulsifier of the reaction, and the dosage is acrylic 2-4% of the total mass of monomers, take the modified carbon nanotubes grafted with acrylamide obtained in step 2, the dosage is 0.01-0.04% of the total mass of acrylic monomers, take distilled water, and the dosage is to make the acrylic monomers , absolute ethanol, emulsifier, initiator, distilled water, and the solid content of the system formed by acrylamide-modified carbon nanotubes is 20-30%; Step 4: Stir the acrylic monomers: acrylic acid, methyl methacrylate, butyl acrylate and acrylamide evenly, and add one-third of the amount into a reactor equipped with a stirrer, a reflux condenser, and a thermometer. Then add ethanol, then, dissolve the modified carbon nanotubes grafted with acrylamide in distilled water and emulsifier, add them into the reactor containing one-third of the basic monomer after ultrasonication for 5 minutes, heat and stir, and the stirring speed is 300-500r/min, when the temperature rises to 70-80°C, pour in a quarter of the initiator dissolved in distilled water, then drop the remaining two-thirds of the monomer and the remaining three-quarters of the initiator at the same time 1h, the initiator is added later than the remaining 2/3 of the monomers. After the dropwise addition, keep the temperature at 80°C for 1h, then lower the temperature to 60°C, adjust the pH to 6-7, and continue to stir for 0.5 h, cooling to room temperature, pouring out, and filtering to obtain the carbon nanotube in-situ modified acrylic resin leather finishing material.