One-component self-crosslinking epoxy-modified acrylate emulsion and preparation method thereof

Abstract

The present invention relates to the technical field of epoxy modified acrylic emulsion, and discloses a single-component self-crosslinking epoxy modified acrylic emulsion and a preparation method thereof. The acrylic emulsion prepared by the present invention comprises the following raw materials in parts by weight: 20-100 parts of butyl acrylate, 2-5 parts of alkenyl carboxylic acid, 80-150 parts of methyl methacrylate, 20-50 parts of ethyl acrylate, 4-6 parts of diacetone acrylamide, 2-3 parts of adipic acid dihydrazide, 5-8 parts of hyperbranched functional polyether, 10-20 parts of epoxy resin, 3-5 parts of acrylamide, 1-2 parts of water-soluble initiator, 5-8 parts of reactive emulsifier, 0.2-0.5 parts of buffer, 1-4 parts of neutralizer, and 200-300 parts of deionized water; the acrylic emulsion prepared by the present invention has excellent water resistance, solvent resistance, mechanical properties, stain resistance, UV resistance and stability.

Description

Technical Field

[0001] The invention relates to the technical field of epoxy modified acrylate emulsion, and in particular to a single-component self-crosslinking epoxy modified acrylate emulsion and a preparation method thereof. Background Art

[0002] Single-component self-crosslinking acrylic emulsions are widely used in outdoor places such as building exterior wall coatings and park sidewalks. They can enhance the beauty of the exterior wall, extend the service life, and provide waterproof and stain-resistant functions. However, there are some defects in the acrylic emulsions currently on the market, including UV resistance, water resistance, and stain resistance. For example, as one of the components of building exterior wall coatings, its addition can improve the adhesion and durability of the coating, but due to the poor water resistance of the acrylic emulsion itself, this will lead to poor water resistance of the coating, which will make the coating easy to fall off and wrinkle, etc. Considering that the exterior wall coating is under sunlight for a long time, the UV resistance also needs to be improved; in view of other shortcomings, the stability, solvent resistance, mechanical properties, and stain resistance of the emulsion can also be improved.

[0003] Epoxy resin has the advantages of excellent corrosion resistance, high bonding strength, low shrinkage, etc., and using it as a modifier can improve the water resistance, bonding performance, film strength, etc. of the emulsion. However, since epoxy resin has a certain brittleness after curing, the mechanical properties of the coating will decrease. Adding hyperbranched polymers can improve the mechanical properties, thereby improving the comprehensive performance of the coating. Therefore, researchers need to develop an epoxy-modified acrylate emulsion so that after it is used in the field of coatings, the coating can have excellent mechanical properties, water resistance, stain resistance, solvent resistance, stability, UV resistance, etc. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a one-component self-crosslinking epoxy-modified acrylate emulsion and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions:

[0006] A one-component self-crosslinking epoxy-modified acrylate emulsion comprises the following raw materials in parts by weight: 20-100 parts of butyl acrylate, 2-5 parts of alkenyl carboxylic acid, 80-150 parts of methyl methacrylate, 20-50 parts of ethyl acrylate, 4-6 parts of diacetone acrylamide, 2-3 parts of adipic acid dihydrazide, 5-8 parts of hyperbranched functional polyether, 10-20 parts of epoxy resin, 3-5 parts of acrylamide, 1-2 parts of water-soluble initiator, 5-8 parts of reactive emulsifier, 0.2-0.5 parts of buffer, 1-4 parts of neutralizer and 200-300 parts of deionized water;

[0007] The hyperbranched functional polyether is prepared by the following steps:

[0008] Step A1, trimethylolpropane triglycidyl ether and tetrabutylammonium bromide are mixed and stirred in N,N-dimethylformamide, and then phloroglucinol is added, and the mixture is reacted at 90°C for 4-5h under nitrogen. After the reaction is completed, tetrahydrofuran is added and stirred for 15min, and then the mixture is washed three times in hot water at 80°C and ether respectively, and then dried in vacuum at 40°C to obtain a hyperbranched polyether;

[0009] Step A2, adding a hyperbranched polyether, triethylamine and toluene into a flask and stirring to mix evenly, slowly adding methacryloyl chloride toluene solution dropwise using a constant pressure dropping funnel under ice-water bath and stirring conditions, dropping for 5 hours, and then reacting at room temperature for 8-12 hours. After the reaction is completed, suction filtration is performed to collect the liquid, and the liquid is washed with 1 mol / L hydrochloric acid solution, 1 mol / L sodium bicarbonate solution and deionized water for 3 times respectively, and then dried with anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain a terminal double-bond hyperbranched polyether;

[0010] Step A3, adding the terminal double-bond hyperbranched polyether and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane into anhydrous tetrahydrofuran and stirring to mix evenly, raising the system temperature to 45-55° C., maintaining the temperature for reaction for 12 hours, and after the reaction is completed, performing reduced pressure distillation to obtain a hyperbranched organosilicon polyether;

[0011] Step A4, stirring dodecane bromide and sodium hydroxide in N,N-dimethylformamide to mix evenly, then adding hyperbranched organosilicon polyether, stirring at room temperature for 24 hours, and purifying to obtain a hyperbranched functional polyether;

[0012] Specifically, in step A1, the usage ratio of trimethylolpropane triglycidyl ether, tetrabutylammonium bromide, N,N-dimethylformamide, phloroglucinol, tetrahydrofuran, hot water and diethyl ether is 0.1-0.3 mol: 0.005-0.015 mol: 100 mL: 0.1-0.2 mol: 100 mL: 200 mL: 200 mL;

[0013] Specifically, in step A2, the ratio of the hyperbranched polyether, triethylamine, toluene, methacryloyl chloride toluene solution, hydrochloric acid solution, sodium bicarbonate solution, deionized water and anhydrous sodium sulfate is 10-20 g: 20-50 g: 200 mL: 100 mL: 200 mL: 200 mL: 200 mL: 50 g, and the methacryloyl chloride toluene solution is prepared by mixing methacryloyl chloride and toluene in a ratio of 50-90 g: 100 mL;

[0014] Specifically, in step A3, the usage ratio of the terminal double bond hyperbranched polyether, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and anhydrous tetrahydrofuran is 10-20 g: 0.5-3 g: 100 mL;

[0015] Specifically, in step A4, the usage ratio of brominated dodecane, sodium hydroxide, N,N-dimethylformamide and hyperbranched organosilicon polyether is 0.02-0.06 mol: 2.5-7.5 g: 100 mL: 10-20 g;

[0016] Specifically, the epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin;

[0017] Specifically, the alkenyl carboxylic acid is one or more of acrylic acid, methacrylic acid, and itaconic acid;

[0018] Specifically, the water-soluble initiator is one or more of ammonium persulfate, potassium persulfate, sodium persulfate, and hydrogen peroxide;

[0019] Specifically, the reactive emulsifier is one or more of SR-10 and SE-10N;

[0020] Specifically, the buffer is one or more of sodium bicarbonate, sodium dihydrogen phosphate, and sodium acetate;

[0021] Specifically, the neutralizing agent is one or more of triethylamine, dimethylethanolamine, triethanolamine, and ammonia water.

[0022] A method for preparing a one-component self-crosslinking epoxy-modified acrylate emulsion comprises the following steps:

[0023] Step S1, weighing raw materials by weight, stirring 30% of deionized water, 70% of reactive emulsifier, 90% of aqueous initiator, acrylamide and diacetone acrylamide at a speed of 500-600 rpm for 10 minutes, then adding butyl acrylate, alkenyl carboxylic acid, methyl methacrylate, ethyl acrylate, hyperbranched functional polyether and epoxy resin, then adjusting the speed to 1000-2000 rpm, and stirring continuously for 30 minutes to obtain a pre-emulsion;

[0024] Step S2, adding 70% of deionized water, 30% of reactive emulsifier and buffer into a reaction kettle, stirring at a speed of 200-300 rpm, and maintaining the stirring temperature at 75-80° C., then adding 10% of aqueous initiator and 10% of pre-emulsion, stirring continuously for 15-30 minutes, and then keeping warm for 30 minutes to obtain a seed emulsion;

[0025] Step S3, maintaining the temperature of the seed emulsion in the reactor at 75-80° C., uniformly dropping the remaining 90% of the pre-emulsion into the reactor, and completing the dropping within 3 hours. After the dropping is completed, heat-retaining the reaction for 2 hours, then lowering the temperature to 45° C., dropping a neutralizing agent within 10 minutes, and controlling the pH to 7-8.5, then adding adipic acid dihydrazide and stirring for 15 minutes, and filtering the material with a 100-200 mesh filter to obtain a single-component self-crosslinking epoxy-modified acrylate emulsion.

[0026] Beneficial effects of the present invention:

[0027] The present invention adopts a method of simultaneously carrying out internal and external crosslinking to improve the overall crosslinking density, thereby improving the comprehensiveness of the coating film; adopts a method of mixed dropwise addition of monomers and initiators to ensure smooth and uniform polymerization of the reaction, so that the molecular weight distribution of the acrylate polymer is relatively uniform, thereby increasing the stability of the performance of the acrylate emulsion.

[0028] The prepared acrylate emulsion of the present invention is added with epoxy resin, and the H atoms on the adjacent carbon of the ether bond in the molecule can form an active center under the action of an initiator, and then undergo a graft copolymerization reaction with the double bonds in a matrix, thereby improving the solvent resistance of the emulsion; acrylic acid and acrylamide are added to participate in the copolymerization reaction of acrylate, and carboxyl groups and amino groups undergo an amide reaction under the action of the initiator, so that the polymerized molecular chains form a cross-linked structure, thereby improving the water resistance of the emulsion; a reactive emulsifier is used, and the double bond structure contained in the reactive emulsifier is utilized to participate in the copolymerization reaction, so that the reactive emulsifier is grafted on the polymer macromolecular chain, and the occurrence of migration and floating phenomenon is avoided during the curing process, thereby improving the anti-fouling ability of the coating film and reducing the amount of the emulsifier; a diacetone acrylamide and adipic acid dihydrazide room temperature cross-linking system is used, and the system belongs to a ketone hydrazide cross-linking system, which can be carried out under room temperature conditions, and forms a cross-linked structure through dehydration condensation, so that a dense cross-linked network can be formed during the drying process of the coating film, thereby improving the strength, water resistance and other comprehensive properties of the coating film.

[0029] In the hyperbranched functional polyether, firstly, the epoxy group in trimethylolpropane triglycidyl ether and the phenolic hydroxyl group in phloroglucinol are reacted to generate a hyperbranched polyether containing hydroxyl groups; secondly, the free hydroxyl groups in the hyperbranched polyether are reacted with the acyl chloride groups in methacryloyl chloride to generate a terminal double-bond hyperbranched polyether; thirdly, part of the double bonds in the terminal double-bond hyperbranched polyether are reacted with the amino groups in N-(2-aminoethyl)-3-aminopropyltrimethoxysilane to generate a hyperbranched silicone polyether containing a secondary amine structure; finally, the secondary amine in the hyperbranched silicone polyether is reacted with the bromine atom in bromododecane to generate a hyperbranched functional polyether. The hyperbranched functional polyether has good dispersibility in the matrix. This is because it has a highly branched structure, which enables it to be evenly dispersed in the system and improves the mechanical properties of the emulsion. When the coating film formed after the emulsion is cured is subjected to external impact stress, the soft segments (ether bonds, etc.) and branched structures in the hyperbranched functional polyether can better absorb or disperse the impact stress, thereby reducing the destructive effect of the external force on the coating film; N-(2-aminoethyl)-3-aminopropyltrimethoxysilane is introduced as an organic silicon, and the siloxane structure it contains can be hydrolyzed to produce silanol groups, which can cross-link with the free hydroxyl groups in the matrix to form a three-dimensional network structure, thereby improving the water resistance and weather resistance of the emulsion. At the same time, it also contains Si-O bonds with higher bond energy, which can effectively resist the damage of ultraviolet rays, thereby improving the anti-ultraviolet ability of the coating film; in addition, the introduction of long-chain hydrophobic alkyl structures improves the hydrophobicity of the emulsion, forms a hydrophobic film on the surface of the emulsion, and thereby improves the anti-fouling performance of the emulsion. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1: Hyperbranched functional polyether, prepared by the following steps:

[0032] Step A1, 0.1 mol of trimethylolpropane triglycidyl ether and 0.005 mol of tetrabutylammonium bromide were mixed and stirred in 100 mL of N, N-dimethylformamide, and then 0.1 mol of phloroglucinol was added, and the mixture was reacted at 90° C. for 4-5 hours under nitrogen. After the reaction was completed, 100 mL of tetrahydrofuran was added and stirred for 15 minutes, and then the mixture was washed three times in 200 mL of hot water at 80° C. and 200 mL of ether, and then dried in vacuum at 40° C. to obtain a hyperbranched polyether;

[0033] Step A2, 10g of hyperbranched polyether, 20g of triethylamine and 200mL of toluene are added to a flask and stirred to mix evenly, and 100mL of methacryloyl chloride toluene solution is slowly added dropwise using a constant pressure dropping funnel under ice water bath and stirring conditions, and the addition is performed for 5h, and then reacted at room temperature for 8h. After the reaction is completed, suction filtration is performed to collect the liquid, and the liquid is washed 3 times with 200mL of 1mol / L hydrochloric acid solution, 200mL of 1mol / L sodium bicarbonate solution and 200mL of deionized water, and then dried with 50g of anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain a terminal double-bond hyperbranched polyether. The methacryloyl chloride toluene solution is prepared by mixing and stirring methacryloyl chloride and toluene in a dosage ratio of 50g:100mL;

[0034] Step A3, adding 10 g of terminal double-bond hyperbranched polyether and 0.5 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane into 100 mL of anhydrous tetrahydrofuran, stirring and mixing evenly, raising the system temperature to 45° C., maintaining the temperature for 12 hours, and after the reaction is completed, performing reduced pressure distillation to obtain a hyperbranched organosilicon polyether;

[0035] Step A4: 0.02 mol of dodecane bromide and 2.5 g of sodium hydroxide were stirred and mixed in 100 mL of N,N-dimethylformamide, and then 10 g of hyperbranched organosilicon polyether was added. The mixture was stirred at room temperature for 24 h and purified to obtain a hyperbranched functional polyether.

[0036] Example 2: Hyperbranched functional polyether, prepared by the following steps:

[0037] Step A1, 0.2 mol of trimethylolpropane triglycidyl ether and 0.01 mol of tetrabutylammonium bromide were mixed and stirred in 100 mL of N, N-dimethylformamide, and then 0.15 mol of phloroglucinol was added, and the mixture was reacted at 90° C. for 4.5 h under nitrogen. After the reaction was completed, 100 mL of tetrahydrofuran was added and stirred for 15 min, and then the mixture was washed three times in 200 mL of hot water at 80° C. and 200 mL of ether, and then dried in vacuum at 40° C. to obtain a hyperbranched polyether;

[0038] Step A2, 15g of hyperbranched polyether, 35g of triethylamine and 200mL of toluene are added to a flask and stirred to mix evenly, and 100mL of methacryloyl chloride toluene solution is slowly added dropwise using a constant pressure dropping funnel under ice-water bath and stirring conditions, and the addition is performed for 5h, and then reacted at room temperature for 10h. After the reaction is completed, suction filtration is performed to collect the liquid, and the liquid is washed 3 times with 200mL of 1mol / L hydrochloric acid solution, 200mL of 1mol / L sodium bicarbonate solution and 200mL of deionized water, and then dried with 50g of anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain a terminal double-bond hyperbranched polyether. The methacryloyl chloride toluene solution is prepared by mixing and stirring methacryloyl chloride and toluene in a dosage ratio of 70g:100mL;

[0039] Step A3, adding 15 g of terminal double-bond hyperbranched polyether and 1.5 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane into 100 mL of anhydrous tetrahydrofuran, stirring and mixing evenly, raising the system temperature to 50° C., maintaining the temperature for reaction for 12 h, and after the reaction is completed, performing reduced pressure distillation to obtain a hyperbranched organosilicon polyether;

[0040] Step A4: 0.04 mol of bromododecane and 5 g of sodium hydroxide were stirred and mixed in 100 mL of N,N-dimethylformamide, and then 15 g of hyperbranched organosilicon polyether was added. The mixture was stirred at room temperature for 24 h and purified to obtain a hyperbranched functional polyether.

[0041] Example 3: Hyperbranched functional polyether, prepared by the following steps:

[0042] Step A1, 0.3 mol of trimethylolpropane triglycidyl ether and 0.015 mol of tetrabutylammonium bromide were mixed and stirred in 100 mL of N, N-dimethylformamide, and then 0.2 mol of phloroglucinol was added, and the mixture was reacted at 90° C. for 5 h under nitrogen. After the reaction was completed, 100 mL of tetrahydrofuran was added and stirred for 15 min, and then the mixture was washed three times in 200 mL of hot water at 80° C. and 200 mL of ether, and then dried in vacuum at 40° C. to obtain a hyperbranched polyether;

[0043] Step A2, 20g of hyperbranched polyether, 50g of triethylamine and 200mL of toluene are added to a flask and stirred to mix evenly, 100mL of methacryloyl chloride toluene solution is slowly added dropwise using a constant pressure dropping funnel under ice water bath and stirring conditions, the addition is performed for 5h, and then the reaction is performed at room temperature for 12h. After the reaction is completed, suction filtration is performed to collect the liquid, and the liquid is washed 3 times with 200mL of 1mol / L hydrochloric acid solution, 200mL of 1mol / L sodium bicarbonate solution and 200mL of deionized water, and then dried with 50g of anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain a terminal double-bond hyperbranched polyether, and the methacryloyl chloride toluene solution is prepared by mixing and stirring methacryloyl chloride and toluene in a dosage ratio of 90g:100mL;

[0044] Step A3, adding 20 g of terminal double-bond hyperbranched polyether and 3 g of N-(2-aminoethyl)-3-aminopropyltrimethoxysilane into 100 mL of anhydrous tetrahydrofuran, stirring and mixing evenly, raising the system temperature to 55° C., maintaining the temperature for 12 hours, and after the reaction is completed, performing reduced pressure distillation to obtain a hyperbranched organosilicon polyether;

[0045] Step A4: 0.06 mol of dodecane bromide and 7.5 g of sodium hydroxide were stirred and mixed in 100 mL of N,N-dimethylformamide, and then 20 g of hyperbranched organosilicon polyether was added. The mixture was stirred at room temperature for 24 h and purified to obtain a hyperbranched functional polyether.

[0046] Example 4: A method for preparing a one-component self-crosslinking epoxy-modified acrylate emulsion comprises the following steps:

[0047] 80 parts of butyl acrylate, 2 parts of acrylic acid, 90 parts of methyl methacrylate, 30 parts of ethyl acrylate, 4 parts of diacetone acrylamide, 2 parts of adipic acid dihydrazide, 5 parts of the hyperbranched functional polyether prepared in Example 1, 10 parts of epoxy resin E-44, 3 parts of acrylamide, 1.4 parts of ammonium persulfate, 5 parts of SR-10, 0.2 parts of sodium bicarbonate, 2 parts of triethylamine, and 200 parts of deionized water;

[0048] Step S1, weighing raw materials by weight, stirring 30% of deionized water, 70% of SR-10, 90% of ammonium persulfate, acrylamide and diacetone acrylamide at a speed of 500 rpm for 10 minutes, then adding butyl acrylate, acrylic acid, methyl methacrylate, ethyl acrylate, the hyperbranched functional polyether prepared in Example 1 and epoxy resin E-44, then adjusting the speed to 1000 rpm, and continuously stirring for 30 minutes to obtain a pre-emulsion;

[0049] Step S2, adding 70% deionized water, 30% SR-10 and sodium bicarbonate into a reaction kettle, stirring at a speed of 200 rpm, and maintaining the stirring temperature at 75° C., then adding 10% ammonium persulfate and 10% pre-emulsion, stirring for 15 minutes, and then keeping warm for 30 minutes to obtain a seed emulsion;

[0050] Step S3, maintaining the temperature of the seed emulsion in the reactor at 75° C., uniformly dropping the remaining 90% of the pre-emulsion into the reactor, and completing the dropping within 3 hours. After the dropping is completed, heat-retaining the reaction for 2 hours, then lowering the temperature to 45° C., dropping triethylamine within 10 minutes, and controlling the pH to 7.5, then adding adipic acid dihydrazide and stirring for 15 minutes, and filtering the material with a 200-mesh filter to obtain a single-component self-crosslinking epoxy-modified acrylate emulsion.

[0051] Example 5: A method for preparing a one-component self-crosslinking epoxy-modified acrylate emulsion comprises the following steps:

[0052] 60 parts of butyl acrylate, 3 parts of methacrylic acid, 120 parts of methyl methacrylate, 35 parts of ethyl acrylate, 5 parts of diacetone acrylamide, 2.5 parts of adipic acid dihydrazide, 6.5 parts of the hyperbranched functional polyether prepared in Example 2, 15 parts of epoxy resin E-44, 4 parts of acrylamide, 1.5 parts of ammonium persulfate, 6 parts of SR-10, 0.3 parts of sodium bicarbonate, 2 parts of triethylamine, and 250 parts of deionized water;

[0053] Step S1, weighing raw materials by weight, stirring 30% of deionized water, 70% of SR-10, 90% of ammonium persulfate, acrylamide and diacetone acrylamide at a speed of 500 rpm for 10 minutes, then adding butyl acrylate, methacrylic acid, methyl methacrylate, ethyl acrylate, the hyperbranched functional polyether prepared in Example 2 and epoxy resin E-44, then adjusting the speed to 1500 rpm, and continuously stirring for 30 minutes to obtain a pre-emulsion;

[0054] Step S2, adding 70% of deionized water, 30% of SR-10 and sodium bicarbonate into a reaction kettle, stirring at a speed of 300 rpm, and maintaining the stirring temperature at 75° C., then adding 10% of ammonium persulfate and 10% of pre-emulsion, stirring for 25 minutes, and then keeping warm for 30 minutes to obtain a seed emulsion;

[0055] Step S3, maintaining the temperature of the seed emulsion in the reactor at 75° C., uniformly dropping the remaining 90% of the pre-emulsion into the reactor, and completing the dropping within 3 hours. After the dropping is completed, heat-retaining the reaction for 2 hours, then lowering the temperature to 45° C., dropping triethylamine within 10 minutes, and controlling the pH to 7.5, then adding adipic acid dihydrazide and stirring for 15 minutes, and filtering the material with a 200-mesh filter to obtain a single-component self-crosslinking epoxy-modified acrylate emulsion.

[0056] Example 6: A method for preparing a one-component self-crosslinking epoxy-modified acrylate emulsion comprises the following steps:

[0057] 80 parts of butyl acrylate, 2.5 parts of acrylic acid, 130 parts of methyl methacrylate, 20 parts of ethyl acrylate, 6 parts of diacetone acrylamide, 3 parts of adipic acid dihydrazide, 8 parts of the hyperbranched functional polyether prepared in Example 3, 20 parts of epoxy resin E-44, 5 parts of acrylamide, 2 parts of ammonium persulfate, 6.5 parts of SE-10N, 0.5 parts of sodium bicarbonate, 3 parts of triethylamine, and 300 parts of deionized water;

[0058] Step S1, weighing raw materials by weight, stirring 30% of deionized water, 70% of SE-10N, 90% of ammonium persulfate, acrylamide and diacetone acrylamide at a speed of 600 rpm for 10 minutes, then adding butyl acrylate, alkenyl carboxylic acid, methyl methacrylate, ethyl acrylate, the hyperbranched functional polyether prepared in Example 3 and epoxy resin E-44, then adjusting the speed to 2000 rpm, and continuously stirring for 30 minutes to obtain a pre-emulsion;

[0059] Step S2, adding 70% of deionized water, 30% of SE-10N and sodium bicarbonate into a reaction kettle, stirring at a speed of 300 rpm, and maintaining the stirring temperature at 80° C., then adding 10% of ammonium persulfate and 10% of pre-emulsion, stirring continuously for 30 minutes, and then keeping warm for 30 minutes to obtain a seed emulsion;

[0060] Step S3, maintaining the temperature of the seed emulsion in the reactor at 80° C., uniformly dropping the remaining 90% of the pre-emulsion into the reactor, and completing the dropping within 3 hours. After the dropping is completed, heat-retaining the reaction for 2 hours, then lowering the temperature to 45° C., dropping triethylamine within 10 minutes, and controlling the pH to 7.5, then adding adipic acid dihydrazide and stirring for 15 minutes, and filtering the material with a 200-mesh filter to obtain a single-component self-crosslinking epoxy-modified acrylate emulsion.

[0061] Comparative Example 1

[0062] This comparative example is an epoxy-modified acrylate emulsion, which is different from Example 6 in that the hyperbranched functional polyether prepared in Example 3 is not added, and the rest is the same.

[0063] Comparative Example 2

[0064] This comparative example is an epoxy-modified acrylic emulsion, which differs from Example 6 in that an equal amount of polyether 330N is used to replace the hyperbranched functional polyether prepared in Example 3, and the rest are the same.

[0065] Performance test: 50g of the emulsion prepared in Examples 4-6 and Comparative Examples 1-2, 2g of dispersant, 3g of thickener, 2.5g of defoamer, 3g of leveling agent and 18g of deionized water were stirred and mixed evenly, then heated to 50°C, stirred at a speed of 3000rpm for 15min, cooled to room temperature, and allowed to stand for 30min to obtain a sample coating. The obtained sample coatings were coated (with a thickness of 20μm) on tinplate, and after surface drying for 30min, placed at 50°C for drying for 1h, and then the performance test was performed; the test results are as follows:

[0066] Detection Methods Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Solid content GB / T2793-1995 50.7 51.0 51.4 48.6 49.2 Ethanol resistance (50%, 24h) GB / T23999-2009 No change No change No change No change No change Water resistance (h) GB / T 1733-1993 438 445 456 379 387 Stain resistance GB / T9780-2013 Level 0 Level 0 Level 0 Level 2 Level 2 hardness GB / T6739-2006 2H 2H 3H H H Calcium ion stability (emulsion) SH / T1608-1995 No significant changes No significant changes No significant changes There is stratification There is stratification UV resistance ASTM D4587 Level 0 Level 0 Level 0 Level 1 Level 1 Impact resistance (cm) GB / T 1732-1993 73 75 78 53 58

[0067] It can be seen from the above table that the one-component self-crosslinking epoxy-modified acrylate emulsion prepared by the present invention has excellent stability. When applied to coatings, it has excellent solid content, solvent resistance, water resistance, stain resistance, UV resistance and impact resistance. Therefore, it can be widely used in the field of coatings.

[0068] The above contents are merely examples and explanations of the concept of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A one-component self-crosslinking epoxy-modified acrylate emulsion, It is characterized in that The invention comprises the following raw materials in parts by weight: 20-100 parts of butyl acrylate, 2-5 parts of alkenyl carboxylic acid, 80-150 parts of methyl methacrylate, 20-50 parts of ethyl acrylate, 4-6 parts of diacetone acrylamide, 2-3 parts of adipic acid dihydrazide, 5-8 parts of hyperbranched functional polyether, 10-20 parts of epoxy resin, 3-5 parts of acrylamide, 1-2 parts of water-soluble initiator, 5-8 parts of reactive emulsifier, 0.2-0.5 parts of buffer, 1-4 parts of neutralizer and 200-300 parts of deionized water; The hyperbranched functional polyether is prepared by the following steps: Step A1, trimethylolpropane triglycidyl ether and tetrabutylammonium bromide are mixed and stirred in N,N-dimethylformamide, and then phloroglucinol is added, and the mixture is reacted at 90°C for 4-5h under nitrogen. After the reaction is completed, tetrahydrofuran is added and stirred for 15min, and then the mixture is washed three times in hot water at 80°C and ether respectively, and then dried in vacuum at 40°C to obtain a hyperbranched polyether; Step A2, adding a hyperbranched polyether, triethylamine and toluene into a flask and stirring to mix evenly, slowly adding methacryloyl chloride toluene solution dropwise using a constant pressure dropping funnel under ice-water bath and stirring conditions, dropping for 5 hours, and then reacting at room temperature for 8-12 hours. After the reaction is completed, suction filtration is performed to collect the liquid, and the liquid is washed with 1 mol / L hydrochloric acid solution, 1 mol / L sodium bicarbonate solution and deionized water for 3 times respectively, and then dried with anhydrous sodium sulfate, filtered, and distilled under reduced pressure to obtain a terminal double-bond hyperbranched polyether; Step A3, adding the terminal double-bond hyperbranched polyether and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane into anhydrous tetrahydrofuran and stirring to mix evenly, raising the system temperature to 45-55° C., maintaining the temperature for reaction for 12 hours, and after the reaction is completed, performing reduced pressure distillation to obtain a hyperbranched organosilicon polyether; Step A4: stir dodecane bromide and sodium hydroxide in N,N-dimethylformamide to mix evenly, then add the hyperbranched organosilicon polyether, stir at room temperature for 24 hours, and purify to obtain the hyperbranched functional polyether.

2. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that Specifically, in step A1, the usage ratio of trimethylolpropane triglycidyl ether, tetrabutylammonium bromide, N,N-dimethylformamide, phloroglucinol, tetrahydrofuran, hot water and diethyl ether is 0.1-0.3 mol: 0.005-0.015 mol: 100 mL: 0.1-0.2 mol: 100 mL: 200 mL: 200 mL.

3. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that In step A2, the amount ratio of the hyperbranched polyether, triethylamine, toluene, methacryloyl chloride toluene solution, hydrochloric acid solution, sodium bicarbonate solution, deionized water and anhydrous sodium sulfate is 10-20g:20-50g:200mL:100mL:200mL:200mL:200mL:50g, and the methacryloyl chloride toluene solution is prepared by mixing methacryloyl chloride and toluene in an amount ratio of 50-90g:100mL.

4. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that In step A3, the usage ratio of the terminal double bond hyperbranched polyether, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane and anhydrous tetrahydrofuran is 10-20 g: 0.5-3 g: 100 mL.

5. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that In step A4, the usage ratio of brominated dodecane, sodium hydroxide, N,N-dimethylformamide and hyperbranched organosilicon polyether is 0.02-0.06 mol: 2.5-7.5 g: 100 mL: 10-20 g.

6. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that The epoxy resin is bisphenol A epoxy resin or bisphenol F epoxy resin.

7. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that The alkenyl carboxylic acid is one or more of acrylic acid, methacrylic acid and itaconic acid.

8. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that The water-soluble initiator is one or more of ammonium persulfate, potassium persulfate, sodium persulfate, and hydrogen peroxide, and the reactive emulsifier is one or more of SR-10 and SE-10N.

9. A one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that The buffer is one or more of sodium bicarbonate, sodium dihydrogen phosphate, and sodium acetate, and the neutralizer is one or more of triethylamine, dimethylethanolamine, triethanolamine, and ammonia water.

10. The method for preparing a one-component self-crosslinking epoxy-modified acrylate emulsion according to claim 1, It is characterized in that The following steps are involved: Step S1, weighing raw materials by weight, stirring 30% of deionized water, 70% of reactive emulsifier, 90% of aqueous initiator, acrylamide and diacetone acrylamide at a speed of 500-600 rpm for 10 minutes, then adding butyl acrylate, alkenyl carboxylic acid, methyl methacrylate, ethyl acrylate, hyperbranched functional polyether and epoxy resin, then adjusting the speed to 1000-2000 rpm, and stirring continuously for 30 minutes to obtain a pre-emulsion; Step S2, adding 70% of deionized water, 30% of reactive emulsifier and buffer into a reaction kettle, stirring at a speed of 200-300 rpm, and maintaining the stirring temperature at 75-80° C., then adding 10% of aqueous initiator and 10% of pre-emulsion, stirring continuously for 15-30 minutes, and then keeping warm for 30 minutes to obtain a seed emulsion; Step S3, maintaining the temperature of the seed emulsion in the reactor at 75-80° C., uniformly dropping the remaining 90% of the pre-emulsion into the reactor, and completing the dropping within 3 hours. After the dropping is completed, heat-retaining the reaction for 2 hours, then lowering the temperature to 45° C., dropping a neutralizing agent within 10 minutes, and controlling the pH to 7-8.5, then adding adipic acid dihydrazide and stirring for 15 minutes, and filtering the material with a 100-200 mesh filter to obtain a single-component self-crosslinking epoxy-modified acrylate emulsion.