Preparation method and application of end-carboxyl hyperbranched polyamide internally crosslinked modified waterborne polyurea

Abstract

The present invention belongs to the technical field of polymer materials, relates to the modification of waterborne polyurea, and particularly relates to a preparation method of an internally crosslinked modified waterborne polyurea with terminal carboxyl hyperbranched polyamide, comprising: dissolving polyisocyanate in a solvent, heating to 90-140°C, adding a catalyst and a coreless terminal carboxyl hyperbranched polyamide, and keeping warm for 1-4 h; adjusting the temperature to 105-160°C, adding a waterborne chain extender and a polyol, and keeping warm for 2-6 h; cooling to 60-90°C, adjusting the pH to 7.0-7.3 with a neutralizing agent, increasing the stirring rate and quickly adding deionized water for dispersion to obtain the product. The solid content of the modified waterborne polyurea prepared by the present invention is 40.3-42.7%, and it can be applied to roll coating, knife coating or spraying such as intaglio printing, relief printing, flexographic printing, etc. Since the hyperbranched polyamide molecule has cavities and more branched chain gaps, the modified waterborne polyurea can further bond / chelate small molecule compounds or be used as a drug carrier, and its application value in the medical field cannot be underestimated.

Description

Technical Field

[0001] The present invention belongs to the technical field of polymer materials, relates to the modification of waterborne polyurea, and particularly relates to a preparation method and application of a waterborne polyurea modified by internal crosslinking of a carboxyl-terminated hyperbranched polyamide. Background Art

[0002] Supramolecular polymer networks have been widely used in fields including sensing, catalysis, adsorption and separation materials, crystal preparation, etc. due to their unique three-dimensional structures and quite wonderful physical and chemical properties, and have become a research hotspot in the fields of chemistry and materials science. Generally, supramolecular polymers are usually constructed by a large number of low-molecular-weight structural units through intermolecular interactions such as hydrophobic / hydrophilic, C-H, π-π, hydrogen bonding, host-guest complexation, and metal coordination.

[0003] Research reports on supramolecular polymers often attract key attention in the industry. For example, Long Yang et al. from Southwest Forestry University constructed a dynamic reversible adhesive based on branched polyamine (PA) and p-formylphenyl acrylate (FPA) through Michael addition and Schiff base reactions. The branched amine can provide a large number of amine groups to react with C═C double bonds and aldehyde groups, and there are a large number of dynamic reversible Schiff base bonds in the resulting branched polymer adhesive system. The Long Yang team prepared an adhesive with a hyperbranched crosslinked network and recyclability. Through repeated bonding-destruction-bonding process experiments, it was proved that the FPA-PA adhesive did not show obvious fatigue phenomena. The adhesive has good bonding properties to various substrates such as steel, aluminum, glass, PVC, PTFE, birch, and bamboo, and the lap shear strengths are 2.4 MPa, 1.7 MPa, 1.4 MPa, 1.3 MPa, 0.4 MPa, 1.6 MPa, and 1.8 MPa respectively.

[0004] For another example, Ying Yang et al. from Guangdong University of Petrochemical Technology functionalized PAMAM with 2-phosphono-1,2,4-butanetricarboxylic acid (PBTCA) and succinic anhydride (SA), and used it as a scale inhibitor. The team prepared PAMAM modified with PBTCA (PAMAM-1), and the first and second generations of PAMAM modified with SA (CAMAM-1 and CAMAM-2). They measured the scale inhibition efficiency of linear low molecular weight polyacrylic acid (LPAA), PBTCA, PAMAM-1, CAMAM-1, CAMAM-2, etc. on CaCO3 and CaSO4 by the static scale inhibition method. The results showed that compared with PBTCA and PAMAM-1, carboxyl-terminated PAMAM had excellent scale inhibition effect. Compared with LPAA and PBTCA, the dendritic structure could effectively improve the scale inhibition efficiency of the scale inhibitor. In addition, increasing the generation number of carboxyl-terminated PAMAM enhanced the scale inhibition performance. The scale inhibition efficiency of CAMAM-2 with a concentration of 10 mg / L on CaCO3 and CaSO4 was 96.3% and 95.2% respectively. When the Ca 2+ concentration was 4000 mg / L, the scale inhibition efficiency of CAMAM-2 was greater than 85%, and when the pH was 5-9, the scale inhibition efficiency could reach more than 90%. The test results of FTIR, XRD, and SEM-EDX confirmed that CaCO3 changed from the stable calcite structure to the metastable aragonite and hexagonalite, and the needle-like structure was broken into small crystals. CAMAM-2 only occupied the crystallization sites during the crystal growth process and distorted the crystal lattice of the calcium scale, but could not adsorb on the surface of the already formed crystals. This article provided strong data support for the application of phosphoric acid or carboxyl-terminated PAMAM in scale inhibition.

[0005] Cecilia C. Torres et al. from universities such as Universidad de Concepcion and Universidad Andres Bello in Chile prepared gold (Au) nanoparticles Au-NPs stabilized by PEG-PAMAM dendrimers under mild aqueous solution conditions. The research results show that these nanoparticles can be used as catalysts to cleanly reduce 4-morpholinonitrobenzene (MNBs) to 4-morpholinoaniline (MANs). This is of great significance in pharmacology and can be used to produce a variety of drugs, including revistin, linezolid, and rivaroxaban, etc. The average particle size of the prepared Au-NPs is 1.6 - 4 nm. The Cecilia C. Torres team carried out the catalytic reaction at room temperature, using sodium borohydride instead of hydrazine as the reducing agent. Au-NPs have high catalytic efficiency in the reaction of reducing MNBs to MANs, reaching a maximum conversion rate of >98% in less than 4 minutes, and no by-products were found. The best PEG-PAMAM-Au catalyst can be recovered by dialysis, still maintaining its activity after 7 consecutive cycles, and the leaching of metals can be ignored. This research provides a valuable and practical green method to obtain aromatic amines with medicinal value through gold-catalyzed reduction. As can be seen from the above, hyperbranched polymers have broad application prospects. Summary of the Invention

[0006] Aiming at the deficiencies existing in the above-mentioned prior art, in order to improve the storage and thermal stability of existing waterborne polyureas, the present invention discloses a preparation method of a carboxyl-terminated hyperbranched polyamide, and obtains improved comprehensive physical and chemical properties of waterborne polyureas through an internal cross-linking modification method.

[0007] Technical Solution

[0008] A preparation method of a carboxyl-terminated hyperbranched polyamide internal cross-linking modified waterborne polyurea, comprising the following steps:

[0009] A. Dissolve polyisocyanate in a solvent and heat it to 90 - 140 °C, preferably 98 °C, add a catalyst and a coreless carboxyl-terminated hyperbranched polyamide, and keep warm for 1 - 4 h, preferably 2 h;

[0010] B. Adjust the temperature to 105 - 160 °C, preferably 135 °C, add a waterborne chain extender and a polyol, and keep warm for 2 - 6 h, preferably 4 h;

[0011] C. Cool down to 60 - 90 °C, preferably 80 °C, adjust the pH to 7.0 - 7.3 with a neutralizing agent, preferably pH 7.1; increase the stirring rate and quickly add deionized water for dispersion, and the obtained waterborne dispersion with a blue fluorescence is the hyperbranched polyamide internal cross-linking modified waterborne polyurea;

[0012] Among them, the material ratio of the polyisocyanate, solvent, catalyst, nuclear-free carboxyl-terminated hyperbranched polyamide, aqueous chain extender, polyol, and deionized water participating in the reaction is 1 mol: 9-15 ml: 1-3 mg: 5-20 mg: 0.1-0.5 mol: 0.9-1.4 mol: 90-160 ml, preferably 1 mol: 10 ml: 2 mg: 16 mg: 0.4 mol: 1.0 mol: 150 ml.

[0013] In a preferred disclosed example of the present invention, the polyisocyanate described in step A is dimethylbiphenyl diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, 4,4ˊ,4〞-triphenylmethane triisocyanate, hexamethylene diisocyanate biuret, 4-chloro-6-methyl-m-phenylene diisocyanate, 3,3-dichlorobiphenyl 4,4-diisocyanate, and preferably isophorone diisocyanate.

[0014] In a preferred disclosed example of the present invention, the solvent described in step A is toluene, xylene, methyl tert-butyl ether, acetone, dioxane, and preferably methyl tert-butyl ether.

[0015] In a preferred disclosed example of the present invention, the catalyst described in step A is N-methylimidazole, bis(morpholinyl)diethyl ether, potassium isooctanoate, dibutyltin oxide, and preferably potassium isooctanoate.

[0016] In a preferred disclosed example of the present invention, the aqueous chain extender described in step B is dimethylol carboxylic acid, and preferably 2,2-dimethylolpropionic acid.

[0017] In a preferred disclosed example of the present invention, the polyol described in step B is polyether diol (PPG-1000, PPG-2000, NJ210, NJ220, NJ230), polytetrahydrofuran diol (PTMG1000, PTMG2000), poly(ε-caprolactone) diol (PCL1000, PCL2000), and preferably NJ210.

[0018] In a preferred disclosed example of the present invention, the neutralizing agent described in step C is NH4OH, NaOH, (HOCH2CH2)3N, (CH3CH2)3N, CH3NH2, and preferably (CH3CH2)3N.

[0019] The solid content of the modified aqueous polyurea prepared by the present invention is between 40.3% and 42.7%, which belongs to the solid content parameters (40.0±5.0%) recognized and commonly used in the coating industry, and is similar to that of ordinary aqueous polyurea with a solid content of 42.97%. Due to the relatively deep internal crosslinking process, the acid value of the system can reach 3.0 - 6.0 mgKOH / g, and the corrosiveness is small or negligible when applied to the surface of an object. Especially when ordinary aqueous polyurea is used for film coating, problems such as film biting and poor gloss often occur, while the modified aqueous polyurea prepared by the present invention is as smooth as a mirror after curing on the film surface, showing a good reflective effect. It can be applied to roll coating, knife coating or spraying on intaglio, relief, flexographic printing plates, etc.; or as a carrier to load small molecule compounds.

[0020] The steric hindrance between the molecular chains of hyperbranched polymers is small and they show the characteristic of diverging radially from a point. They sense the external temperature change and the molecular chains rotate freely while maintaining the original spherical structure. Therefore, they have good heat / cold resistance characteristics. The molecular chains of the aqueous polyurea modified with it have a hyperbranched structure, so their physical and chemical properties tend to be stable, showing excellent storage and heat / cold resistance;

[0021] The non-nucleated carboxyl-terminated hyperbranched polyamide of the present invention has a preparation method including the following steps:

[0022] (1) Dissolve the amino ketone compound in solvent A and heat it to 50 - 90°C, preferably 60°C; dropwise add I2 as a catalyst, add (Boc)2O, and keep warm for 20 - 90 min, preferably 70 min; then remove most of the solvent to obtain substance A; wherein, the molar ratio of the amino ketone compound, (Boc)2O, solvent, and I2 is 1 mol:0.95 - 1.03 mol:10 - 50 ml:1 - 3 drops, preferably 1 mol:1.02 mol:40 ml:2 drops; the amino ketone compound is m-aminoacetophenone, 4-aminoacetophenone, o-aminoacetophenone or 1-amino-2-propanone, preferably 4-aminoacetophenone; the solvent A is methyl tert-butyl ether, dioxane, dimethylformamide, carbon tetrachloride or ethyl acetate, preferably dioxane;

[0023] (2) Dissolve the carboxyl acetaldehyde compound in solvent B and heat it to 70 - 120 °C, preferably 78 °C; add the mixed solution of protonic acid and methanol, keep warm for 1 - 4 h, preferably 2 h; then remove most of the solvent to obtain substance B; wherein, the mass concentration of the mixed solution of protonic acid and methanol is 0.1 - 2.0%, preferably 0.9%; the material ratio of the carboxyl acetaldehyde compound, solvent B, and the mixed solution of protonic acid and methanol is 1 mol: 20 - 45 ml: 5 - 10 ml, preferably 1 mol: 25 ml: 8 ml; the carboxyl acetaldehyde compound is 2-carboxybenzaldehyde, 3-carboxybenzaldehyde, p-carboxybenzaldehyde or glyoxylic acid, preferably p-carboxybenzaldehyde; the solvent B is ethyl acetate, petroleum ether, methyl tert-butyl ether, n-butyl ester or acetone, preferably acetone; the protonic acid is concentrated sulfuric acid, fuming nitric acid, concentrated hydrochloric acid or perchloric acid, preferably concentrated sulfuric acid;

[0024] (3) Dissolve substance A and substance B in solvent C and heat it to 85 - 140 °C, preferably 110 °C; add NaOH, then add the 4-formamidinium formate hydrochloride solution, keep warm for 1 - 4 h, preferably 2 h; then remove most of the solvent to obtain the monomer precursor containing a pyrimidine structure; wherein, the concentration of the 4-formamidinium formate hydrochloride solution is 0.9 - 1.2 mol / ml, preferably 1.1 mol / ml; the material ratio of NaOH, substance A, substance B, solvent C, and the 4-formamidinium formate hydrochloride solution is 0.2 - 0.9 mg: 1 mol: 1.0 - 1.3 mol: 8 - 22 ml: 1.0 - 1.1 ml, preferably 0.5 mg: 1 mol: 1.1 mol: 19 ml: 1 ml; the solvent C is acetone, ethyl acetate, isopropyl ester, dioxane or ether, preferably acetone;

[0025] (4) Dissolve the monomer precursor containing a pyrimidine structure in solvent D and heat it to 100 - 150 °C, preferably 130 °C. Add a TFA / NaHCO₃ solution containing 0.1 - 0.5% by mass, preferably 0.3% NaHCO₃, and keep it warm for 30 - 90 min, preferably 50 min. Adjust the temperature to 40 - 80 °C, preferably 60 °C, add a freshly prepared LiOH / methanol mixed solution at 0.9 - 1.5 mol / ml, preferably 1.3 mol / ml, and keep it warm for 10 - 50 min, preferably 30 min. Add a protonic acid to adjust the pH to 5.5 - 6.5, preferably a pH value of 6.0. Then remove most of the solvent to obtain a multi-site active functional group monomer containing amino and carboxyl groups, and store it sealed in a dry environment. Among them, the material ratio of the monomer precursor containing a pyrimidine structure, solvent D, the TFA / NaHCO₃ mixed solution, and the LiOH / methanol mixed solution is 1 mol: 10 - 50 ml: 0.8 - 1.2 ml: 0.8 - 1.3 ml, preferably 1 mol: 45 ml: 0.9 ml: 0.9 ml; the solvent D is ethyl acetate, dimethylformamide, acetone, methyl isobutyl ketone, chloroform, or carbon tetrachloride, preferably methyl isobutyl ketone; the protonic acid is hydrochloric acid, sulfuric acid, or acetic acid, preferably hydrochloric acid;

[0026] (5) Dissolve the catalyst in solvent E and heat it to 70 - 120 °C, preferably 115 °C. Add the multi-site active functional group monomer containing amino and carboxyl groups and keep it warm for 1 - 5 h, preferably 3 h. Then remove most of the solvent to obtain a core-free end-carboxyl hyperbranched polyamide, and store it in the dark. Among them, the material ratio of the catalyst, solvent E, and the multi-site active functional group monomer containing amino and carboxyl groups is 1 - 4 drops: 10 - 25 ml: 1.0 - 1.4 mol, preferably 2 drops: 24 ml: 1.1 mol; the solvent E is toluene, xylene, acetone, butanone, cyclohexanone, ethyl acetate, n-butanol, preferably xylene; the catalyst is an organotin compound, preferably diisobutyltin dilaurate.

[0027] The end-carboxyl hyperbranched polyamide prepared by the present invention is characterized by a three-dimensional spherical structure with a polyol as the core, branched chains radiating outwards in all directions, and carboxyl groups connected to the ends of each chain segment. Due to its relatively low cohesive energy and the stretching and divergence of the molecular chains, the viscosity of the modified waterborne polyurea is lower and the particle size is smaller after modification; the introduction of a hyperbranched structure and abundant hydrophilic carboxyl groups in the system enhances the dispersibility in the aqueous system, and macroscopically presents an ideal blue clear and transparent state and a smaller surface tension.

[0028] Experimental method

[0029] (1) Fourier transform infrared spectroscopy (FT-IR)

[0030] Using KBr as a control, first take an appropriate amount of KBr and grind it into extremely fine powder in an agate mortar. After pressing it into a transparent thin film with a mold and performing infrared scanning to form a background image, then take a small amount of multi-site active functional group monomers and carboxyl-terminated hyperbranched polyamide and mix them evenly with the aforementioned extremely fine KBr powder. After infrared scanning to form a test image, finally subtract the KBr background value to obtain the infrared spectra of the two; Figure 1 Provide the relevant samples of Example 1.

[0031] (2) Deliquescence test

[0032] Use a fluidized bed reactor to test the deliquescence performance of carboxyl-terminated hyperbranched polyamide at normal temperature and pressure, humidity of 45% RH, and gas velocity of 30 m3 / h. Record the change value of the deliquescence rate over time. The calculation formula is as shown in Equation (1):

[0033] ζ = (WT - W0) / W0 × 100% (1)

[0034] Where: ζ —— Deliquescence rate (%); T —— Time (min); WT —— Sample mass at time T; W0 —— Initial sample mass; Figure 2 Provide the relevant samples of Example 1.

[0035] (3) Determination of polymer solid content

[0036] Weigh about 2 g of the polymer in a petri dish, place it horizontally in a temperature-controlled drying oven, maintain the temperature at 60°C - 70°C, take out the petri dish with the sample after 6 - 7 h, cool it in a desiccator and then weigh it. Then put it back into the constant-temperature drying oven, take it out and weigh it again after an interval of 30 min. Repeat the above operation, and require the difference between the two weighings to be within 0.01 g. The calculation formula is as shown in Equation (2):

[0037] S = (W2 - W0) / (W1 - W0) × 100% (2)

[0038] Where, S —— Polymer solid content (%); w0 —— Mass of the petri dish; w1 —— Total mass of the polymer and the petri dish before drying; w2 —— Total mass of the polymer and the petri dish after constant weight.

[0039] (4) Determination of polymer thermal stability and freeze-thaw stability

[0040] Dilute the polymer sample with deionized water to a solid content of about 20%. Place the diluted sample in a 60°C temperature-controlled oven, observe and record the state change of the sample after 24 h; place the diluted sample in a -20°C refrigerator, take out the sample after 18 h and melt it at room temperature (about 25°C) for 6 h. Repeat the operation 5 times, and then observe and record the state change of the sample.

[0041] (5) Determination of polymer apparent viscosity

[0042] The apparent viscosity of the sample was measured using a digital display viscometer (NDJ-9S, Shanghai Precision Scientific Instruments Co., Ltd.). At room temperature of 25 °C and high shear rate (2000 s -1 ), highly accurate measurement can be ensured.

[0043] (6) Determination of polymer particle size

[0044] The sample was diluted to the same concentration with deionized water for use, and the particle size of the sample was determined using a laser particle size analyzer (Model BIC-9010, Brookhaven Instruments Corporation, USA).

[0045] (7) Determination of polymer surface tension

[0046] The surface tension of the sample was measured using a surface / interface tensiometer (Model DCAT 11, Dataphysics Instruments GmbH, Germany). At room temperature, all measurements and data collection were automatically controlled by software SCAT 31.

[0047] (8) Friction resistance test of the coating

[0048] The sample was evenly coated on the surface of a paper printed with dark ink, and the coating was about 1.6 ± 0.05 g / m 2 . Using an ink friction tester (Model 2000, Sutherland Company, USA), a pressure of 4 pounds and a rotation speed of 85 revolutions / min were set, and the condition of the coating after friction was observed.

[0049] Beneficial effects

[0050] In the present invention, an AB2-type multi-site active functional group monomer is prepared using an amino ketone compound and a hydroxyacetaldehyde compound as monomer precursors. The hyperbranched polyamide formed by polymerization presents a spherical structure with dot-like divergence and contains a large number of rigid conjugated structures and terminal carboxyl groups, and its physicochemical properties are unique; the waterborne polyurea modified with it exhibits excellent storage stability, wetting performance, etc., and can greatly improve the friction resistance of printed products as an ink protection layer, and has great application prospects in the field of coating materials; in addition, due to the presence of cavities and more branched chain gaps in the hyperbranched polyamide molecule, the water-washed polyurea modified with it can further bond / chelate small molecule compounds or be used as a drug carrier, and its application value in the medical field cannot be underestimated. Description of the drawings

[0051] Figure 1 . Infrared spectrum of multi-site active functional group monomer and terminal carboxyl hyperbranched polyamide;

[0052] Figure 2 . Diagram of the change of the deliquescence rate of terminal carboxyl hyperbranched polyamide with time;

[0053] Figure 3. Friction resistance test results of modified waterborne polyurea and ordinary varnish coatings, where (a) is the ordinary varnish coating and (b) is the modified waterborne polyurea coating. Detailed implementation manners

[0054] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, and these all belong to the protection scope of the present invention.

[0055] Example 1

[0056] A method for crosslinking and modifying waterborne polyurea with carboxyl-terminated hyperbranched polyamide includes the following steps:

[0057] Put 1 mol of 4-aminobenzophenone into 40 ml of dioxane, stir and dissolve it, then heat it to a temperature of 60 °C; add 2 drops of I2 as a catalyst, add 1.02 mol of (Boc)2O, and keep the temperature for 70 min; then remove most of the solvent to obtain substance A for standby;

[0058] Put 1 mol of p-carboxybenzaldehyde into 25 ml of acetone, stir and dissolve it, then heat it to a temperature between 78 °C; add 8 ml of a mixed solution of 0.9% sulfuric acid and methanol, and keep the temperature for 2 h; then remove most of the solvent to obtain substance B for standby;

[0059] Put 1 mol of substance A and 1.1 mol of substance B into 19 ml of acetone, stir and dissolve them, then heat it to a temperature of 110 °C; add 0.5 mg of NaOH, then add 1.0 ml of a 1.1 mol / ml 4-formamidinium formate hydrochloride solution, and keep the temperature for 2 h; then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for standby;

[0060] Put 1 mol of the above monomer precursor into 45 ml of methyl isobutyl ketone, stir and dissolve it, then heat it to a temperature of 130 °C, add 0.9 ml of a TFA solution containing 0.3% NaHCO3 by mass concentration, and keep the temperature for 50 min; adjust the temperature to 60 °C, add 0.9 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 1.3 mol / ml, and keep the temperature for 30 min; add hydrochloric acid to adjust the pH to 6.0; then remove most of the solvent to obtain a multi-site active functional group monomer containing amino and carboxyl groups, and store it sealed in a dry environment;

[0061] Put 2 drops of diisobutyltin dilaurate into 24 ml of xylene, stir to dissolve, and then heat it within the temperature range of 115 °C. Add 1.1 mol of the above multi-site active functional group monomer, and keep the temperature for 3 h. Then remove most of the solvent to obtain a nucleus-free carboxyl-terminated hyperbranched polyamide, and store it in the dark.

[0062] Put 1 mol of isophorone diisocyanate into 10 ml of methyl tert-butyl ether, stir to dissolve, and then heat it to 98 °C. Add 2 mg of potassium isooctanoate and 16 mg of the above carboxyl-terminated hyperbranched polyamide, and keep the temperature for 2 h. Adjust the temperature to 135 °C, add 0.4 mol of 2,2-dimethylolpropionic acid and 1.0 mol of NJ210, and keep the temperature for 4 h. Cool down to 80 °C, add (CH3CH2)3N to adjust the pH to 7.1. Increase the stirring rate and quickly add 150 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide internally crosslinked modified aqueous polyurea.

[0063] The synthesis route is as follows:

[0064]

[0065] Example 2

[0066] A method for internally crosslinking and modifying an aqueous polyurea with a carboxyl-terminated hyperbranched polyamide, comprising the following steps:

[0067] Put 1 mol of 4-aminophenylethanone into 10 ml of dioxane, stir to dissolve, and then heat it to 50 °C. Dropwise add 1 drop of I2 as a catalyst, add 0.95 mol of (Boc)2O, and keep the temperature for 20 min. Then remove most of the solvent to obtain substance A for standby.

[0068] Put 1 mol of p-carboxybenzaldehyde into 20 ml of acetone, stir to dissolve, and then heat it to 70 °C. Add 5 ml of a mixed solution of 0.1% sulfuric acid and methanol, and keep the temperature for 1 h. Then remove most of the solvent to obtain substance B for standby.

[0069] Put 1 mol of substance A and 1.0 mol of substance B into 8 ml of acetone, stir to dissolve, and then heat it to 85 °C. Add 0.2 mg of NaOH and then add 1.0 ml of a 0.9 mol / ml solution of 4-formamidinium formate hydrochloride, and keep the temperature for 1 h. Then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for standby.

[0070] Dissolve 1 mol of the above monomer precursor in 10 ml of methyl isobutyl ketone by stirring, then heat it to 100 °C. Add 0.8 ml of a TFA solution containing 0.1% NaHCO₃ by mass, and keep it warm for 30 min. Adjust the temperature to 40 °C, add 0.8 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 0.9 mol / ml, and keep it warm for 10 min. Adjust the pH to 5.5 with hydrochloric acid. Then remove most of the solvent to obtain a monomer with multi-site active functional groups containing amino and carboxyl groups, and store it sealed in a dry environment;

[0071] Dissolve 1 drop of diisobutyltin dilaurate in 10 ml of xylene by stirring, then heat it in the temperature range of 70 °C. Add 1.0 mol of the above multi-site active functional group monomer, and keep it warm for 1 h. Then remove most of the solvent to obtain a coreless carboxyl-terminated hyperbranched polyamide, and store it in the dark;

[0072] Dissolve 1 mol of isophorone diisocyanate in 9 ml of methyl tert-butyl ether by stirring, then heat it in the temperature range of 90 °C. Add 1 mg of potassium isooctanoate and 5 mg of the above carboxyl-terminated hyperbranched polyamide, and keep it warm for 1 h. Adjust the temperature to 105 °C, add 0.1 mol of 2,2-dimethylolpropionic acid and 0.9 mol of NJ210, and keep it warm for 2 h. Cool down to 60 °C, add (CH₃CH₂)₃N to adjust the pH to 7.0. Increase the stirring rate and quickly add 90 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide internally cross-linked modified aqueous polyurea.

[0073] Example 3

[0074] A method for internally cross-linking and modifying an aqueous polyurea with a carboxyl-terminated hyperbranched polyamide, comprising the following steps:

[0075] Dissolve 1 mol of 4-aminophenylethanone in 50 ml of dioxane by stirring, then heat it to 90 °C. Dropwise add 3 drops of I₂ as a catalyst, add 1.03 mol of (Boc)₂O, and keep it warm for 90 min. Then remove most of the solvent to obtain substance A for standby;

[0076] Dissolve 1 mol of p-carboxybenzaldehyde in 45 ml of acetone by stirring, then heat it to 120 °C. Add 10 ml of a mixed solution of 2.0% sulfuric acid and methanol, and keep it warm for 4 h. Then remove most of the solvent to obtain substance B for standby;

[0077] Put 1 mol of substance A and 1.3 mol of substance B into 22 ml of acetone, stir and dissolve, then heat to 140 °C. Add 0.9 mg of NaOH, then add 1.1 ml of a 4-formamidinoformic acid hydrochloride solution with a concentration of 1.2 mol / ml, and keep it warm for 4 h. Then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for standby;

[0078] Dissolve 1 mol of the above monomer precursor in 50 ml of methyl isobutyl ketone by stirring, then heat it to 150 °C. Add 1.2 ml of a TFA solution containing 0.5% by mass of NaHCO₃, and keep the temperature for 90 min. Adjust the temperature to 80 °C, add 1.3 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 1.5 mol / ml, and keep the temperature for 50 min. Adjust the pH to 6.5 with hydrochloric acid. Then remove most of the solvent to obtain a monomer with multi-site active functional groups containing amino and carboxyl groups, and store it sealed in a dry environment;

[0079] Dissolve 4 drops of diisobutyltin dilaurate in 25 ml of xylene by stirring, then heat it to 120 °C. Add 1.4 mol of the above multi-site active functional group monomer, and keep the temperature for 5 h. Then remove most of the solvent to obtain a coreless carboxyl-terminated hyperbranched polyamide, and store it protected from light;

[0080] Dissolve 1 mol of isophorone diisocyanate in 15 ml of methyl tert-butyl ether by stirring, then heat it to 140 °C. Add 3 mg of potassium isooctanoate and 20 mg of the above carboxyl-terminated hyperbranched polyamide, and keep the temperature for 4 h. Adjust the temperature to 160 °C, add 0.5 mol of 2,2-dimethylolpropionic acid and 1.4 mol of NJ210, and keep the temperature for 6 h. Cool down to 90 °C, add (CH₃CH₂)₃N to adjust the pH to 7.3. Increase the stirring rate and quickly add 160 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide internally cross-linked modified aqueous polyurea.

[0081] Example 4

[0082] A method for internally cross-linking and modifying an aqueous polyurea with a carboxyl-terminated hyperbranched polyamide, comprising the following steps:

[0083] Dissolve 1 mol of m-aminophenylethone in 20 ml of methyl tert-butyl ether by stirring, then heat it to 70 °C. Dropwise add 1 drop of I₂ as a catalyst, add 0.96 mol of (Boc)₂O, and keep the temperature for 30 min. Then remove most of the solvent to obtain substance A for standby;

[0084] Dissolve 1 mol of 2-carboxybenzaldehyde in 30 ml of ethyl acetate by stirring, then heat it to 80 °C. Add 7 ml of a mixed solution of 1.0% fuming nitric acid and methanol, and keep the temperature for 3 h. Then remove most of the solvent to obtain substance B for standby;

[0085] Dissolve 1 mol of substance A and 1.2 mol of substance B in 9 ml of ethyl acetate, stir to dissolve, and then heat to 90 °C; add 0.3 mg of NaOH, and then add 1.0 ml of a 1.0 mol / ml solution of 4-formamidino formate hydrochloride, and keep warm for 1 h; then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for standby;

[0086] Dissolve 1 mol of the above monomer precursor in 30 ml of ethyl acetate, stir to dissolve, and then heat to 110 °C. Add 1.0 ml of a TFA solution containing 0.2% NaHCO3 by mass concentration, and keep warm for 40 min; adjust the temperature to 50 °C, add 1.0 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 1.1 mol / ml, and keep warm for 20 min; add sulfuric acid to adjust the pH to 6.5; then remove most of the solvent to obtain a multi-site active functional group monomer containing amino and carboxyl groups, and store it sealed in a dry environment;

[0087] Dissolve 3 drops of diisobutyltin dilaurate in 12 ml of toluene, stir to dissolve, and then heat to 80 °C; add 1.2 mol of the above multi-site active functional group monomer, and keep warm for 4 h; then remove most of the solvent to obtain a coreless end-carboxyl hyperbranched polyamide, and store it protected from light;

[0088] Dissolve 1 mol of dimethylbiphenyl diisocyanate in 11 ml of toluene, stir to dissolve, and then heat to 102 °C; add 3 mg of N-methylimidazole and 7 mg of the above end-carboxyl hyperbranched polyamide, and keep warm for 3 h; adjust the temperature to 148 °C, add 0.3 mol of 2,2-dimethylolbutanoic acid and 1.1 mol of PTMG1000, and keep warm for 5 h; cool to 76 °C, add NH4OH to adjust the pH to 7.2; increase the stirring rate and quickly add 135 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide inner cross-linked modified aqueous polyurea.

[0089] Example 5

[0090] A method for inner cross-linking and modifying aqueous polyurea with end-carboxyl hyperbranched polyamide, comprising the following steps:

[0091] Dissolve 1 mol of o-aminophenetone in 32 ml of dimethylamide, stir to dissolve, and then heat to 56 °C; add 3 drops of I2 as a catalyst, add 0.98 mol of (Boc)2O, and keep warm for 84 min; then remove most of the solvent to obtain substance A for standby;

[0092] Dissolve 1 mol of 3-carboxybenzaldehyde in 41 ml of n-butyl ester, stir to dissolve, and then heat to 83 °C; add 9 ml of a mixed solution of concentrated hydrochloric acid and methanol with a concentration of 1.4%, and keep warm for 3 h; then remove most of the solvent to obtain substance B for standby;

[0093] Dissolve 1 mol of substance A and 1.2 mol of substance B in 17 ml of dioxane, stir to dissolve, and then heat to 92 °C; add 0.7 mg of NaOH, then add 1.1 ml of a 0.9 mol / ml solution of 4-formamidino formate hydrochloride, and keep warm for 3 h; then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for standby;

[0094] Dissolve 1 mol of the above monomer precursor in 34 ml of chloroform, stir to dissolve, and then heat to 121 °C. Add 1.1 ml of a TFA solution containing 0.4% NaHCO3 by mass concentration, and keep warm for 45 min; adjust the temperature to 65 °C, add 1.2 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 1.4 mol / ml, and keep warm for 33 min; add acetic acid to adjust the pH to 5.9; then remove most of the solvent to obtain a multi-site active functional group monomer containing amino and carboxyl groups, and store it sealed in a dry environment;

[0095] Dissolve 3 drops of diisobutyltin dilaurate in 11 ml of cyclohexanone, stir to dissolve, and then heat to 104 °C; add 1.2 mol of the above multi-site active functional group monomer, and keep warm for 2 h; then remove most of the solvent to obtain a core-free carboxyl-terminated hyperbranched polyamide, and store it away from light;

[0096] Dissolve 1 mol of 4,4ˊ,4〞-triphenylmethane triisocyanate in 14 ml of dioxane, stir to dissolve, and then heat to 128 °C; add 3 mg of dibutyltin oxide and 13 mg of the above carboxyl-terminated hyperbranched polyamide, and keep warm for 4 h; adjust the temperature to 110 °C, add 0.5 mol of 2,2-dimethylolbutyric acid and 1.1 mol of PCL1000, and keep warm for 6 h; cool down to 63 °C, add NaOH to adjust the pH to 7.2; increase the stirring rate and quickly add 105 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide internally crosslinked modified aqueous polyurea.

[0097] Example 6

[0098] A method for internally crosslinking and modifying an aqueous polyurea with a carboxyl-terminated hyperbranched polyamide, comprising the following steps:

[0099] Dissolve 1 mol of 1-amino-2-propanone in 28 ml of ethyl acetate, stir to dissolve, and then heat to 86 °C; add 1 drop of I2 as a catalyst, add 0.99 mol of (Boc)2O, and keep warm for 48 min; then remove most of the solvent to obtain substance A for standby;

[0100] Dissolve 1 mol of 2-carboxybenzaldehyde, 3-carboxybenzaldehyde, p-carboxybenzaldehyde, and glyoxylic acid in 25 ml of ethyl acetate, petroleum ether, methyl tert-butyl ether, n-butyl ester, and acetone, stir to dissolve, and then heat to 79 °C; add 9 ml of a mixed solution of 1.4% concentrated sulfuric acid, fuming nitric acid, concentrated hydrochloric acid, perchloric acid, and methanol, and keep warm for 124 h; then remove most of the solvent to obtain Substance B for later use;

[0101] Dissolve 1 mol of Substance A and 1.2 mol of Substance B in 17 ml of diethyl ether, stir to dissolve, and then heat to 93 °C; add 0.8 mg of NaOH, then add 1.1 ml of a 0.9 mol / ml solution of 4-formamidinoformic acid hydrochloride, and keep warm for 3 h; then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure for later use;

[0102] Dissolve 1 mol of the above monomer precursor in 26 ml of carbon tetrachloride, stir to dissolve, and then heat to 107 °C. Add 1.2 ml of a TFA solution containing 0.4% NaHCO3 by mass concentration, and keep warm for 38 min; adjust the temperature to 72 °C, add 1.3 ml of a newly prepared LiOH / methanol mixed solution with a molar concentration of 1.5 mol / ml, and keep warm for 28 min; add acetic acid to adjust the pH to 6.4; then remove most of the solvent to obtain a multi-site active functional group monomer containing amino and carboxyl groups, and store it sealed in a dry environment;

[0103] Put 3 drops of diisobutyltin dilaurate into 14 ml of n-butanol, stir to dissolve, and then heat to 95 °C; add 1.4 mol of the above multi-site active functional group monomer, and keep warm for 4 h; then remove most of the solvent to obtain a coreless end-carboxyl hyperbranched polyamide, and store it in the dark;

[0104] Dissolve 1 mol of 4-chloro-6-methyl-m-phenylene diisocyanate in 16 ml of dioxane, stir to dissolve, and then heat to 92 °C; add 3 mg of bis(morpholinyl)diethyl ether and 14 mg of the above end-carboxyl hyperbranched polyamide, and keep warm for 3 h; adjust the temperature to 121 °C, add 0.2 mol of 2,2-dimethylolpropionic acid and 1.3 mol of PPG-2000, and keep warm for 3 h; cool to 87 °C, add (HOCH2CH2)3N to adjust the pH to 7.2; increase the stirring rate and quickly add 144 ml of deionized water for dispersion. The obtained blue-light-emitting aqueous dispersion is the hyperbranched polyamide internal cross-linked modified aqueous polyurea.

[0105] Perform infrared spectroscopy tests on the multi-site active functional group monomer and end-carboxyl hyperbranched polyamide prepared in Example 1, and the results are as follows Figure 1 shown. Both are at 3415 cm -1There are strong absorption peaks everywhere, which mainly come from the stretching vibration of N-H in free -NH2 or -CO-NH-, and the peak shape is relatively wide. This is mainly attributed to the strong electrophilicity of N in the pyrimidine structure obtained by the dehydration condensation of amino and ketone, forming a hydrogen bond force slightly weaker than ordinary covalent bonds, which is superimposed on the stretching vibration of N-H to form a wide peak; both have obvious absorption peaks at 1610 cm -1 which mainly come from the bending vibration of N-H, and have obvious absorption peaks at 1410 cm -1 , 1020 cm -1 which mainly come from the stretching vibration of C-N. From this, it can be determined that both have -NH2 groups and the N structural parts involved are similar; both have obvious absorption peaks at 2874 cm -1 and 1352 cm -1 which can generally be attributed to the stretching and bending vibrations of -OH in carboxylic acid; both have obvious absorption peaks at 1766 cm -1 which mainly come from the stretching vibration of the C=O structure, and the absorption peak of the terminal carboxyl hyperbranched polyamide at this wavenumber is significantly weakened. This is mainly attributed to the fact that N in -CO-NH- weakens the electron cloud density of C=O and the corresponding peak weakens. From this, it can be determined that both have a certain number of -COOH groups, and there is a larger proportion of amidation in the molecular structure of the latter; in summary, it can be determined that the multi-site active functional group monomer contains active amino and carboxyl groups, and the self-assembled terminal carboxyl hyperbranched polyamide contains a large number of active carboxyl groups, which can be further applied to the modification of polymers.

[0106] The deliquescence performance of the terminal carboxyl hyperbranched polyamide prepared in Example 1 was tested, and the results are as Figure 2 shown. It can be seen from the figure that the sample has obvious deliquescence phenomenon at 0 - 2 min, the deliquescence efficiency weakens within 2 - 6 min, and the deliquescence rate remains constant at about 22.0% after 8 min, and the sample absorption reaches saturation. From this, it can be determined that the sample has good deliquescence performance, which is mainly attributed to the strong hydrophilicity of carboxyl groups, and it also further verifies the existence of abundant carboxyl groups in the molecular structure of the terminal carboxyl hyperbranched polyamide.

[0107] The physical properties of the modified waterborne polyurea and ordinary waterborne polyurea prepared in some examples were characterized, and the test results are shown in Table 1.

[0108] Table 1 Test results of the physical properties of polymers

[0109]

[0110] (Note: — indicates no change)

[0111] The friction resistance test results of the modified waterborne polyurea and ordinary varnish coatings are as Figure 3As shown in the figure. Among them, (a) represents the ordinary varnish coating, and (b) represents the modified waterborne polyurea coating. It can be seen that the modified waterborne polyurea coating has stronger protection for the underlying ink. After friction, the ordinary varnish coating fades significantly and the original ink layer is severely damaged. This is mainly due to the introduction of a large number of hyperbranched chain segments with conjugated pyrimidine, benzene ring and other structures in the system, which improves the rigidity of the system; numerous active functional groups improve the intramolecular crosslinking degree and the film-forming property is better; at the same time, the rich terminal carboxyl groups, pyrimidines, etc. form hydrogen bond forces with each other, so the friction resistance of the coating is improved.

[0112] In summary, it can be concluded that the waterborne polyurea modified by the end-carboxyl hyperbranched polyamide provided by the present invention has excellent physical and chemical properties and broad application prospects.

[0113] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the description of the present invention, or directly or indirectly applied in other related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A preparation method of a waterborne polyurea modified by internal crosslinking of a carboxyl-terminated hyperbranched polyamide, characterized in that, It includes the following steps: A. Dissolve the polyisocyanate in a solvent and heat it to 90 - 140 °C, add a catalyst and a coreless carboxyl - terminated hyperbranched polyamide, and keep the temperature for 1 - 4 h; Among them, the preparation method of the coreless carboxyl - terminated hyperbranched polyamide includes: (1) Dissolve the amino - ketone compound in solvent A and heat it to 50 - 90 °C, dropwise add I2 as a catalyst, add (Boc)2O, keep the temperature for 20 - 90 min, and then remove most of the solvent to obtain substance A; among them, the molar ratio of the amino - ketone compound, (Boc)2O, solvent, and I2 is 1 mol: 0.95 - 1.03 mol: 10 - 50 ml: 1 - 3 drops. The amino - ketone compound is m - aminoacetophenone, 4 - aminoacetophenone, o - aminoacetophenone, or 1 - amino - 2 - propanone, and the solvent A is methyl tert - butyl ether, dioxane, dimethylformamide, carbon tetrachloride, or ethyl acetate; (2) Dissolve the carboxyl - acetaldehyde compound in solvent B and heat it to 70 - 120 °C, add a mixed solution of a protonic acid and methanol, keep the temperature for 1 - 4 h, and then remove most of the solvent to obtain substance B; among them, the mass concentration of the mixed solution of the protonic acid and methanol is 0.1 - 2.0%; the molar ratio of the carboxyl - acetaldehyde compound, solvent B, and the mixed solution of the protonic acid and methanol is 1 mol: 20 - 45 ml: 5 - 10 ml; the carboxyl - acetaldehyde compound is 2 - carboxybenzaldehyde, 3 - carboxybenzaldehyde, p - carboxybenzaldehyde, or glyoxylic acid; the solvent B is ethyl acetate, petroleum ether, methyl tert - butyl ether, n - butyl ester, or acetone; the protonic acid is concentrated sulfuric acid, fuming nitric acid, concentrated hydrochloric acid, or perchloric acid; (3) Dissolve substance A and substance B in solvent C and heat it to 85 - 140 °C, add NaOH, then add a 4 - formamidinium formate hydrochloride solution, keep the temperature for 1 - 4 h, and then remove most of the solvent to obtain a monomer precursor containing a pyrimidine structure; among them, the concentration of the 4 - formamidinium formate hydrochloride solution is 0.9 - 1.2 mol / ml, and the molar ratio of NaOH, substance A, substance B, solvent C, and the 4 - formamidinium formate hydrochloride solution is 0.2 - 0.9 mg: 1 mol: 1.0 - 1.3 mol: 8 - 22 ml: 1.0 - 1.1 ml. The solvent C is acetone, ethyl acetate, isopropyl ester, dioxane, or ether; (4) Dissolve the monomer precursor containing a pyrimidine structure in solvent D and heat it to 100 - 150 °C. Add a TFA / NaHCO₃ solution containing 0.1 - 0.5% NaHCO₃ by mass concentration, and keep it warm for 30 - 90 min. Adjust the temperature to 40 - 80 °C, add a newly prepared LiOH / methanol mixed solution with a concentration of 0.9 - 1.5 mol / ml, and keep it warm for 10 - 50 min. Add a protonic acid to adjust the pH to 5.5 - 6.

5. Then remove most of the solvent to obtain a monomer with multi-site active functional groups containing amino and carboxyl groups, and store it sealed in a dry environment. Among them, the material ratio of the monomer precursor containing a pyrimidine structure, solvent D, the TFA / NaHCO₃ mixed solution, and the LiOH / methanol mixed solution is 1 mol: 10 - 50 ml: 0.8 - 1.2 ml: 0.8 - 1.3 ml; the solvent D is ethyl acetate, dimethylformamide, acetone, methyl isobutyl ketone, chloroform, or carbon tetrachloride; the protonic acid is hydrochloric acid, sulfuric acid, or acetic acid; (5) Dissolve the catalyst in solvent E and heat it to 70 - 120 °C. Add the monomer with multi-site active functional groups containing amino and carboxyl groups, and keep it warm for 1 - 5 h. Then remove most of the solvent to obtain a coreless end-carboxyl hyperbranched polyamide, and store it protected from light. Among them, the material ratio of the catalyst, solvent E, and the monomer with multi-site active functional groups containing amino and carboxyl groups is 1 - 4 drops: 10 - 25 ml: 1.0 - 1.4 mol; the solvent E is toluene, xylene, acetone, butanone, cyclohexanone, ethyl acetate, or butanol; the catalyst is an organotin compound; B. Adjust the temperature to 105 - 160 °C, add a water-based chain extender and a polyol, and keep it warm for 2 - 6 h; C. Cool down to 60 - 90 °C, adjust the pH to 7.0 - 7.3 with a neutralizing agent, increase the stirring rate and quickly add deionized water for dispersion. The obtained blue-light-emitting water-based dispersion is the hyperbranched polyamide internally cross-linked modified water-based polyurea.

2. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step A, the polyisocyanate is dissolved in a solvent and heated to 98 °C, and a catalyst and a coreless end-carboxyl hyperbranched polyamide are added, and kept warm for 2 h.

3. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step A, the polyisocyanate is any one of dimethylbiphenyl diisocyanate, p-phenylene diisocyanate, isophorone diisocyanate, 4,4ˊ,4〞-triphenylmethane triisocyanate, hexamethylene diisocyanate biuret, 4-chloro-6-methyl-m-phenylene diisocyanate, 3,3-dichlorobiphenyl 4,4-diisocyanate.

4. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step A, the polyisocyanate is isophorone diisocyanate.

5. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step A, the solvent is any one of toluene, xylene, methyl tert-butyl ether, acetone, and dioxane.

6. The preparation method of the end-carboxyl hyperbranched polyamide internally cross-linked modified aqueous polyurea according to claim 1, characterized in that: In step A, the solvent is methyl tert-butyl ether.

7. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step A, the catalyst is any one of N-methylimidazole, bis(morpholinyl)diethyl ether, potassium isooctanoate, and dibutyltin oxide.

8. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: The catalyst in step A is potassium isooctanoate.

9. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step (1), the amino ketone compound is dissolved in solvent A and heated to 60 °C; I2 is added dropwise as a catalyst, (Boc)2O is added, and the mixture is kept warm for 70 min; then most of the solvent is removed to obtain substance A.

10. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (1), the material ratio of the amino ketone compound, (Boc)2O, the solvent, and I2 is 1 mol: 1.02 mol: 40 ml: 2 drops.

11. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (1), the amino ketone compound is 4-aminobenzophenone.

12. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step (1), the solvent A is dioxane.

13. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (2), the carboxyl acetaldehyde compound is dissolved in solvent B and heated to 78 °C, a mixed solution of a protonic acid and methanol is added, and the mixture is kept warm for 2 h; then most of the solvent is removed to obtain substance B.

14. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (2), the mass concentration of the mixed solution of the protonic acid and methanol is 0.9%.

15. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (2), the material ratio of the carboxyl acetaldehyde compound, solvent B, and the mixed solution of the protonic acid and methanol is 1 mol: 25 ml: 8 ml.

16. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 1, characterized in that: In step (2), the carboxyl acetaldehyde compound is p-carboxybenzaldehyde.

17. The preparation method of the end-carboxyl hyperbranched polyamide internally cross-linked modified aqueous polyurea according to claim 1, characterized in that: In step (2), the solvent B is acetone.

18. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step (2), the protonic acid is concentrated sulfuric acid.

19. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (3), substance A and substance B are dissolved in solvent C and heated to 110 °C, NaOH is added, and then a solution of 4-formamidinecarboxylic acid hydrochloride is added, and the mixture is kept warm for 2 h; then most of the solvent is removed to obtain a monomer precursor containing a pyrimidine structure.

20. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (3), the concentration of the solution of 4-formamidinecarboxylic acid hydrochloride is 1.1 mol / ml.

21. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (3), the material ratio of NaOH, substance A, substance B, solvent C, and the solution of 4-formamidinecarboxylic acid hydrochloride is 0.5 mg: 1 mol: 1.1 mol: 19 ml: 1 ml.

22. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step (3), the solvent C is acetone.

23. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 1, characterized in that: In step (4), the monomer precursor containing a pyrimidine structure is dissolved in solvent D and heated to 130 °C, a TFA solution containing 0.3% NaHCO3 (TFA / NaHCO3) is added, and the mixture is kept warm for 50 min; the temperature is adjusted to 60 °C, a newly prepared mixed solution of LiOH / methanol with a concentration of 1.3 mol / ml is added, and the mixture is kept warm for 30 min; a protonic acid is added to adjust the pH to 6.0; then most of the solvent is removed to obtain a multi-site active functional group monomer containing amino and carboxyl groups, which is sealed and stored in a dry environment.

24. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (4), the material ratio of the monomer precursor containing a pyrimidine structure, solvent D, the TFA / NaHCO3 mixed solution, and the LiOH / methanol mixed solution is 1 mol: 45 ml: 0.9 ml: 0.9 ml.

25. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 1, characterized in that: In step (4), the solvent D is methyl isobutyl ketone.

26. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (4), the protonic acid is hydrochloric acid.

27. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 1, characterized in that: In step (5), the catalyst is dissolved in solvent E and heated to 115 °C, the multi-site active functional group monomer containing amino and carboxyl groups is added, and the mixture is kept warm for 3 h; then most of the solvent is removed to obtain a core-free carboxyl-terminated hyperbranched polyamide, which is stored in the dark.

28. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step (5), the material ratio of the catalyst, solvent E, and the multi-site active functional group monomer containing amino and carboxyl groups is 2 drops: 24 ml: 1.1 mol.

29. The preparation method of the waterborne polyurea modified by end-carboxyl hyperbranched polyamide internal crosslinking according to claim 1, characterized in that: In step (5), the solvent E is xylene.

30. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, wherein: In step (5), the catalyst is diisobutyltin dilaurate.

31. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step B, the temperature is adjusted to 135 °C, an aqueous chain extender and a polyol are added, and the temperature is maintained for 4 h.

32. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: In step C, the temperature is lowered to 80 °C, the pH is adjusted to 7.1 with a neutralizing agent, the stirring rate is increased, and deionized water is quickly added for dispersion to obtain a blue-light-emitting aqueous dispersion.

33. The preparation method of the end-carboxyl hyperbranched polyamide internally cross-linked and modified aqueous polyurea according to claim 1, wherein: The material ratio of the polyisocyanate, solvent, catalyst, nucleus-free carboxyl-terminated hyperbranched polyamide, aqueous chain extender, polyol, and deionized water participating in the reaction is 1 mol: 9 - 15 ml: 1 - 3 mg: 5 - 20 mg: 0.1 - 0.5 mol: 0.9 - 1.4 mol: 90 - 160 ml.

34. The preparation method of the end-carboxyl hyperbranched polyamide internally cross-linked and modified aqueous polyurea according to claim 33, characterized in that: The material ratio of the polyisocyanate, solvent, catalyst, nucleus-free carboxyl-terminated hyperbranched polyamide, aqueous chain extender, polyol, and deionized water participating in the reaction is 1 mol: 10 ml: 2 mg: 16 mg: 0.4 mol: 1.0 mol: 150 ml.

35. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: The aqueous chain extender in step B is dimethylol carboxylic acid.

36. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 35, characterized in that: The aqueous chain extender in step B is 2,2-dimethylolpropionic acid.

37. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: The polyol in step B is any one of polyether diol, polytetrahydrofuran diol, and poly(ε-caprolactone) diol.

38. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 37, characterized in that: The polyether diol in step B is any one of PPG-1000, PPG-2000, NJ210, NJ220, and NJ230.

39. The preparation method of the waterborne polyurea modified by internal crosslinking of the carboxyl-terminated hyperbranched polyamide according to claim 37, characterized in that: The polytetrahydrofuran diol in step B is PTMG1000 or PTMG2000.

40. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 37, characterized in that: The poly(ε-caprolactone) diol in step B is PCL1000 or PCL2000.

41. The preparation method of the end-carboxyl hyperbranched polyamide internally cross-linked modified aqueous polyurea according to claim 1, characterized in that: The polyol in step B is polyether diol NJ210.

42. The preparation method of the end-carboxyl hyperbranched polyamide internally crosslinked and modified aqueous polyurea according to claim 1, characterized in that: The neutralizing agent in step C is any one of NH4OH, NaOH, (HOCH2CH2)3N, (CH3CH2)3N, and CH3NH2.

43. The preparation method of the waterborne polyurea modified by internal crosslinking of carboxyl-terminated hyperbranched polyamide according to claim 1, characterized in that: The neutralizing agent in step C is (CH3CH2)3N.

44. The carboxyl-terminated hyperbranched polyamide internally crosslinked and modified aqueous polyurea prepared by the method according to any one of claims 1-43, characterized in that: The solid content is between 40.3% and 42.7%.

45. Use of the end-carboxyl hyperbranched polyamide internally cross-linked and modified aqueous polyurea as described in claim 44, characterized in that: It is applied to intaglio, relief, and flexographic printing plates by roll coating, knife coating, or spraying, or used as a carrier to load small molecule compounds.

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