Preparation method of an organic-solvent-free aqueous polyurethane-acrylate toughening agent

Abstract

The present invention relates to a preparation method of a solvent-free aqueous polyurethane-acrylate toughening agent. Calculated by weight, it includes adding dehydrated polyethylene glycol, isocyanate, "similar" solvent acrylate substances, and hydroxyl-terminated polybutadiene into a reaction kettle, adding dibutyltin dilaurate (DBTDL) for reaction, adding a small molecule chain extender and dimethylolbutyric acid and continuing the reaction; then adding hydroxyacrylate as a capping agent for reaction to obtain a polyurethane-acrylate prepolymer. Then the temperature is lowered, and a mixed aqueous solution of a sulfonic acid group chain extender and sodium hydroxide is added under high-speed stirring for neutralization and emulsification. Finally, an initiator solution is added dropwise while heating, and then the reaction is carried out under insulation to obtain a toughened aqueous polyurethane-acrylate emulsion. By adopting the production method designed in the present invention, the use of a large amount of organic solvents can be avoided, the production method is environmentally friendly and safe, and the solvent-free aqueous polyurethane-acrylate prepared has good high-temperature and low-temperature resistance properties.

Description

Technical Field

[0001] The present invention belongs to the field of polymer materials, and particularly relates to a preparation method of a waterborne polyurethane-acrylate toughening agent without organic solvents. Background Art

[0002] In the northwestern region of China, the winter temperature is relatively low. In order not to affect the construction of the construction industry, higher requirements are put forward for the waterproof protection of buildings. In recent years, a series of waterborne coatings have been studied to try to solve such problems. For example, two-component spray polyurea waterproof coatings and brushable polyurea (single- and two-component) waterproof coatings have the best effects. However, some problems have also been found in the use process. The main problems are that the two-component rapid-setting spray polyurea has a fast curing speed, poor penetration and wetting properties on the substrate, high requirements for the substrate, especially for the treatment of a large number of concrete substrates, which are prone to defects. In addition, the internal stress of the material is large, and edge curling and peeling are likely to occur; the brushable polyurea (single- and two-component) waterproof coatings have relatively high requirements for the construction environment. When constructing on a wet substrate or in a high-humidity environment, pinholes and bulges are likely to occur, and the wet bond strength is low, resulting in peeling. Summary of the Invention

[0003] Aiming at the above defects or improvement requirements of the prior art, the purpose of the present invention is to provide a preparation method of a waterborne polyurethane-acrylate toughening agent without organic solvents.

[0004] To achieve the above purpose, the technical solution of the present invention is as follows: A preparation method of a waterborne polyurethane-acrylate toughening agent without organic solvents, calculated by weight, includes the following steps:

[0005] S1. Add 25-50 parts of polyethylene glycol, 30-60 parts of isocyanate monomer, 35-65 parts of acrylate monomer, and 1-5 parts of hydroxyl-terminated polybutadiene into a reaction kettle. Add 0.12-0.25 parts of dibutyltin dilaurate at 60-80 °C and react for 1.5-3 h, and set aside;

[0006] S2. Continue to add 1-3 parts of a small molecule chain extender and 5-10 parts of a hydrophilic chain extender to the reaction kettle in step S1 at 60-80 °C and react for 1.5-3 h, and set aside;

[0007] S3. Add 1-3 parts of an acrylic hydroxy ester capping agent to the product obtained in step S2 and react for 1-3 h to obtain a polyurethane-acrylate prepolymer, and set aside;

[0008] S4. Cool the reaction kettle containing the polyurethane-acrylate prepolymer in step S3 to 30-45 °C, add a mixed aqueous solution of 20-35 parts of a sulfonic acid group post-chain extender and 1-2 parts of sodium hydroxide under high-speed stirring for neutralization and emulsification, and then keep warm for 0.3-0.6 h;

[0009] S5. Heat the product obtained in step S4 to 70 - 85 °C, add 0.5 - 1.5 parts of initiator solution dropwise, with the dropping time being 0.5 - 2 h, and then keep it warm for 2 - 4 h to obtain a waterborne polyurethane - acrylate toughening agent without organic solvents.

[0010] Furthermore, the polyethylene glycol is polyethylene glycol treated by vacuum dehydration.

[0011] Furthermore, the isocyanate monomer is isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4 - cyclohexane diisocyanate, trimethyl - 1,6 - hexamethylene diisocyanate or cyclohexane dimethylene diisocyanate.

[0012] Furthermore, in step S1, the acrylate monomer is one, two or a mixture of any ratio of glycidyl methacrylate, vinyl acetate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, n - octyl methacrylate, 2 - ethylhexyl methacrylate.

[0013] Furthermore, in step S2, the low - molecular - weight chain extender is one or several of ethylene glycol, 1,4 - butanediol, propylene glycol, neopentyl glycol or 1,6 - hexanediol.

[0014] Furthermore, the hydrophilic chain extender in step S2 is one of diethanolamine, triethanolamine, N - methyldiethanolamine, dimethylolpropionic acid (DMPA), dimethylolbutyric acid (DMBA).

[0015] Furthermore, in step S3, the hydroxyacrylate - type capping agent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate and hydroxypropyl acrylate.

[0016] Furthermore, the sulfonic - group post - chain extender in step S4 has a molecular structure of

[0017]

[0018] Furthermore, the initiator in step S5 is one of potassium persulfate, ammonium persulfate, azodiisobutyramidine hydrochloride (V - 50).

[0019] As another aspect of the present invention, it also relates to a modified epoxy resin waterproof coating. Calculated by weight, the coating is divided into two components, A and B. The composition of component A is: 8 - 12 parts of water, 1 - 2 parts of Dow RM - 8W associative thickener from the United States, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO2, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 50 - 80 parts of epoxy resin, 0.05 - 0.15 part of defoamer BYK - 038; The composition of component B is: 1 - 2 parts of thickener, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO2, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 80 - 120 parts of self - made solvent - free waterborne polyurethane - acrylate toughening agent, 8 - 10 parts of curing agent, 0.05 - 0.15 part of defoamer.

[0020] Generally speaking, compared with the prior art through the above - conceived technical solution of the present invention, the following beneficial effects can be achieved:

[0021] (1) In the preparation method of the solvent - free waterborne polyurethane - acrylate toughening agent of the present invention, acrylate monomers are used as "similar" solvents to replace organic solvents such as acetone, which can avoid the use of a large amount of organic solvents. Triethylamine is not used in the preparation process, so a waterborne polyurethane - acrylate with zero VOC can be obtained.

[0022] (2) The preparation method of the solvent - free waterborne polyurethane - acrylate toughening agent of the present invention uses a new type of liquid rubber with good flexibility, hydroxyl - terminated polybutadiene (HTPB), to enhance the toughness of waterborne polyurethane - acrylate. This substance can react with cross - linking agents and chain - extending agents at normal or high temperatures to form a three - dimensional network structure. This kind of substance has excellent mechanical properties, good acid and alkali resistance, low viscosity, good transparency, aging resistance, hydrolysis resistance, low - temperature resistance and wear resistance.

[0023] (3) The modified epoxy resin waterproof coating with the solvent - free waterborne polyurethane - acrylate toughening agent of the present invention has excellent mechanical properties, high tensile strength and large elongation at break. It has aging resistance, does not turn yellow, good toughness, good frost resistance, waterproof property, is environmentally friendly, meets the current requirements of green environmental protection, and is suitable for waterproof protection of hydraulic structures in cold regions. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is the TEM diagram of the waterborne polyurethane - acrylate toughening agent of the preferred embodiment of the present invention;

[0025] Figure 2 It is the schematic diagram of the mechanical test results of the preferred embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0026] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0027] The present invention provides a technical solution:

[0028] A preparation method of a solvent-free aqueous polyurethane-acrylate toughening agent, characterized in that, by weight, it comprises the following steps:

[0029] S1. Add 25-50 parts of polyethylene glycol, 30-60 parts of isocyanate monomer and 35-65 parts of acrylate monomer (as a "solvent" analog), and 1-5 parts of hydroxyl-terminated polybutadiene to a reaction kettle, and add 0.12-0.25 parts of dibutyltin dilaurate at 60-80 °C and react for 1.5-3 h, and set aside;

[0030] Among them, the isocyanate monomer is isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, trimethyl-1,6-hexamethylene diisocyanate or cyclohexane dimethylene diisocyanate;

[0031] Among them, the acrylate monomer is one, two or a mixture of any ratio of glycidyl methacrylate, vinyl acetate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate.

[0032] S2. Continue to add 1-3 parts of small molecule chain extender and 5-10 parts of hydrophilic chain extender to the reaction kettle of S1 at 60-80 °C and react for 1.5-3 h, and set aside; among them, the polyethylene glycol is polyethylene glycol treated by vacuum dehydration, and the polyethylene glycol is PEG 1000 、PEG 2000 One of them, polyethylene glycol is the soft segment in polyurethane, and the molecular weight of the soft segment has a certain influence on the mechanical properties of polyurethane.

[0033] S3. Add 1-3 parts of acrylate hydroxyester capping agent to the product obtained in step S2 and react for 1-3 h to obtain a polyurethane-acrylate prepolymer, and set aside; among them, the acrylate hydroxyester capping agent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate and hydroxypropyl acrylate.

[0034] S4. Cool down the reactor containing the polyurethane-acrylate prepolymer in step S3 to 30 - 45°C, add a mixed aqueous solution of 20 - 35 parts of a sulfonic acid group post-chain extender and 1 - 2 parts of sodium hydroxide under high-speed stirring for neutralization and emulsification, and then keep the temperature for 0.3 - 0.6 h;

[0035] Among them, the molecular structure of the sulfonic acid group post-chain extender is:

[0036]

[0037] S5. Raise the temperature of the product obtained in step S4 to 70 - 85°C, dropwise add 0.5 - 1.5 parts of an initiator solution, the dropping time is 0.5 - 2 h, and then keep the temperature for 2 - 4 h to obtain a solvent-free aqueous polyurethane-acrylate toughener; among them, the initiator is one of potassium persulfate, ammonium persulfate, and azodiisobutyramidine hydrochloride (V-50).

[0038] As a preferred solution, the small molecule chain extender in step S2 is one or more of ethylene glycol, 1,4-butanediol, diethylene glycol, propylene glycol, neopentyl glycol, or 1,6-hexanediol. (Polyurethane is basically a block copolymer with a linear structure similar to the (A-B)x type. Its soft segment is composed of polyol macromolecules, and the hard segment is formed by the reaction of diisocyanate with low molecular weight diols. The carbon-carbon chain length in the low molecular weight diol molecule affects the microphase separation of the soft and hard segments and the crystallization of the urethane hard segment. Only when the hard chain is well-oriented, crystallization and orientation can make it easier to form hydrogen bonds between polymer molecules, which means that better ordered crystallization can be produced. The steric hindrance effect of crystallization and the migration of polymer segments ultimately show that the polymer has excellent toughness and hardness)

[0039] As a preferred solution, the hydrophilic chain extender in step S2 is one of diethanolamine, triethanolamine, N-methyldiethanolamine, dimethylolpropionic acid (DMPA), and dimethylolbutyric acid (DMBA). The role of the hydrophilic chain extender is to introduce hydrophilic groups while extending the polyurethane prepolymer with terminal isocyanate groups.

[0040] Based on the above solvent-free waterborne polyurethane-acrylate toughener, it also relates to a solvent-free waterborne polyurethane-acrylate toughened epoxy resin waterproof coating. Calculated by weight, the coating is divided into two components, A and B. The composition of component A is: 8 - 12 parts of water, 1 - 2 parts of Dow RM-8W associative thickener from the United States, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO2, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 50 - 80 parts of epoxy resin, 0.05 - 0.15 part of defoamer BYK-038; The composition of component B is: 1 - 2 parts of thickener, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO2, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 80 - 120 parts of the above solvent-free waterborne polyurethane-acrylate toughener, 8 - 10 parts of curing agent, 0.05 - 0.15 part of defoamer.

[0041] Among them, the thickener is selected from Dow RM-8W associative thickener from the United States; the defoamer is selected from one of BYK-034, BYK-035, BYK-037, BYK-038 produced by BYK Company in Germany.

[0042] Example 1

[0043] The preparation method of a solvent-free waterborne polyurethane-acrylate toughened epoxy resin waterproof coating provided in this example mainly includes two parts: modifying waterborne polyurethane-acrylate with HTPB and its compounding with epoxy resin.

[0044] Preparation of the first part of the solvent-free waterborne polyurethane-acrylate toughener: 30 parts of isophorone diisocyanate, 30 parts of polyethylene glycol PEG 1000 , 2 parts of hydroxyl-terminated polybutadiene and 35 parts of methyl methacrylate are added to a dry reaction kettle equipped with a thermometer and a stirring device. At 60°C, 0.1 part of dibutyltin dilaurate is added and reacted for 1.5 h; 2 parts of small molecule chain extender ethylene glycol and 6 parts of diethanolamine are added and reacted for 1.3 h, 1 part of capping agent hydroxypropyl acrylate is added and reacted for 1.5 h to obtain a polyurethane-acrylate prepolymer. Then the temperature is lowered to 35°C, and 24.5 parts of sulfonic acid group post-chain extender, 1.4 parts of sodium hydroxide and 390 parts of aqueous solution are added under high-speed stirring for neutralization and emulsification, and then kept warm for 0.3 h. The temperature of the system is raised to 80°C, and a solution prepared by dissolving 1 part of potassium persulfate in 20 parts of water is added dropwise, and the dropping time is 1 h, and then kept warm for 2.5 h. A solvent-free waterborne polyurethane-acrylate toughener is obtained.

[0045] Preparation of a waterborne polyurethane - acrylate toughening agent modified epoxy resin waterproof coating without organic solvents in the second part: First, add 10 parts of water, 1.6 parts of thickener, and 0.75 parts of dispersant and stir evenly. Then, successively add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 60 parts of epoxy resin emulsion, and finally add 0.1 part of defoamer and stir evenly to obtain Component A; First, add 1.6 parts of thickener and 0.75 parts of dispersant and stir evenly. Then, successively add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 100 parts of self - made waterborne polyurethane - acrylate toughening agent without organic solvents and stir evenly. Add 9 parts of curing agent, and finally add 0.1 part of defoamer and stir evenly to obtain Component B; Mix Component A and Component B together to obtain a waterborne polyurethane - acrylate toughening agent modified epoxy resin waterproof coating without organic solvents.

[0046] Example 2

[0047] The preparation method of a waterborne polyurethane - acrylate toughening agent modified epoxy resin waterproof coating without organic solvents provided in this example mainly includes two parts: modifying waterborne polyurethane - acrylate with HTPB and its compounding with epoxy resin.

[0048] Preparation of the waterborne polyurethane - acrylate toughening agent without organic solvents in the first part: 42 parts of isophorone diisocyanate, 35 parts of polyethylene glycol PEG 2000 , 3 parts of hydroxyl - terminated polybutadiene, and 40 parts of vinyl acetate are added to a dry reaction kettle equipped with a thermometer and a stirring device. Add 0.15 part of dibutyltin dilaurate at 65 °C and react for 2 h; Add 3 parts of small - molecule chain extender 1,4 - butanediol and 8 parts of triethanolamine and react for 2 h. Add 2 parts of capping agent hydroxyethyl acrylate and react for 1.5 h to obtain a polyurethane - acrylate prepolymer. Then cool down to 35 °C, add 26 parts of sulfonic acid - based post - chain extender, 1.4 parts of sodium hydroxide, and 390 parts of aqueous solution under high - speed stirring for neutralization and emulsification. Then keep warm for 0.5 h, raise the system temperature to 70 °C, and drop - wise add a solution prepared by mixing 0.5 part of ammonium persulfate and 20 parts of water. The dropping time is 0.5 h, and then keep warm for 3 h. Obtain a waterborne polyurethane - acrylate toughening agent without organic solvents.

[0049] Preparation of a waterborne polyurethane - acrylate toughener - modified epoxy resin waterproof coating without organic solvents in the second part: First, add 10 parts of water, 1.6 parts of thickener, and 0.75 parts of dispersant and stir evenly. Then, sequentially add 6 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 60 parts of epoxy resin emulsion, and finally add 0.1 part of defoamer and stir evenly to obtain Component A; First, add 1.6 parts of thickener and 0.75 parts of dispersant and stir evenly. Then, sequentially add 9 parts of TiO2, 14 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 90 parts of self - made waterborne polyurethane - acrylate toughener without organic solvents and stir evenly. Add 9 parts of curing agent, and finally add 0.1 part of defoamer and stir evenly to obtain Component B; Mix Component A and Component B together to obtain a waterborne polyurethane - acrylate toughener - modified epoxy resin waterproof coating without organic solvents.

[0050] Example 3

[0051] The preparation method of a waterborne polyurethane - acrylate toughener - modified epoxy resin waterproof coating without organic solvents provided in this example mainly includes two parts: modifying waterborne polyurethane - acrylate with HTPB and its compounding with epoxy resin.

[0052] Preparation of a waterborne polyurethane - acrylate toughener without organic solvents in the first part: 50 parts of dicyclohexylmethane diisocyanate, 45 parts of polyethylene glycol PEG 2000 , 3 parts of hydroxyl - terminated polybutadiene, and 52 parts of glycidyl methacrylate are added to a dry reaction kettle equipped with a thermometer and a stirring device. Add 0.2 part of dibutyltin dilaurate at 75°C and react for 2 h; Add 4 parts of small - molecule chain extender diethylene glycol and 10 parts of dimethylolbutyric acid DMBA and react for 2.5 h. Add 2 parts of capping agent hydroxyethyl acrylate and react for 2.5 h to obtain a polyurethane - acrylate prepolymer. Then cool down to 40°C, add 32 parts of sulfonic - group post - chain extender, 1.4 parts of sodium hydroxide, and 390 parts of aqueous solution under high - speed stirring for neutralization and emulsification. Then keep warm for 0.6 h. Raise the system temperature to 85°C and drop - wise add a solution prepared from 1 part of initiator and 20 parts of water, and the dropping time is 2.5 h. Then keep warm for 3.5 h. Obtain a waterborne polyurethane - acrylate toughener without organic solvents.

[0053] Preparation of a waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating without organic solvents in the second part: First, add 10 parts of water, 1.6 parts of thickener, and 0.75 parts of dispersant and stir evenly. Then, successively add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 70 parts of epoxy resin emulsion, and finally add 0.1 part of defoamer and stir evenly to obtain Component A; First, add 1.6 parts of thickener and 0.75 parts of dispersant and stir evenly. Then, successively add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc powder and stir evenly. Add 100 parts of self-made waterborne polyurethane-acrylate toughener without organic solvents and stir evenly. Add 9 parts of curing agent, and finally add 0.1 part of defoamer and stir evenly to obtain Component B; Mix Component A and Component B together to obtain a waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating without organic solvents.

[0054] Example 4

[0055] The preparation method of a waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating without organic solvents provided in this example mainly includes two parts: modifying waterborne polyurethane-acrylate with HTPB and its compounding with epoxy resin.

[0056] Preparation of waterborne polyurethane-acrylate toughener without organic solvents in the first part: 58 parts of 1,4-cyclohexane diisocyanate (CHDI), 50 parts of polyethylene glycol PEG 2000 , 5 parts of hydroxyl-terminated polybutadiene, and 60 parts of ethyl methacrylate are added to a dry reaction kettle equipped with a thermometer and a stirring device. Add 0.25 part of dibutyltin dilaurate at 80 °C and react for 3 h; add 2 parts of small molecule chain extender neopentyl glycol and 10 parts of dimethylolpropionic acid DMPA and react for 3 h. Add 2.5 parts of capping agent hydroxyethyl methacrylate and react for 2 h to obtain a polyurethane-acrylate prepolymer. Then cool down to 40 °C, add 32 parts of sulfonic acid group post-chain extender, 1.4 parts of sodium hydroxide, and 390 parts of aqueous solution under high-speed stirring for neutralization and emulsification, and then keep warm for 0.5 h. Raise the system temperature to 76 °C and dropwise add a solution prepared from 1 part of azodiisobutyramidine hydrochloride and 20 parts of water. The dropping time is 2 h, and then keep warm for 3 h. Obtain a waterborne polyurethane-acrylate toughener without organic solvents.

[0057] Preparation of a solvent-free waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating: First, add 10 parts of water, 1.6 parts of thickener, and 0.75 parts of dispersant and stir evenly. Then, sequentially add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc and stir evenly. Next, add 60 parts of epoxy resin emulsion, and finally add 0.1 part of defoamer and stir evenly to obtain Component A. First, add 1.6 parts of thickener and 0.75 parts of dispersant and stir evenly. Then, sequentially add 7.5 parts of TiO2, 12.5 parts of heavy calcium carbonate, and 12.5 parts of talc and stir evenly. Next, add 100 parts of self-made solvent-free waterborne polyurethane-acrylate toughener and stir evenly. Then, add 9 parts of curing agent, and finally add 0.1 part of defoamer and stir evenly to obtain Component B. Mix Component A and Component B together to obtain the solvent-free waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating.

[0058] The microscopic morphology of the particles of the waterborne polyurethane-acrylate toughener was observed by transmission electron microscopy. The TEM images are shown in Figure 1 , where a and b are TEM images with magnifications of 100,000 times and 50,000 times respectively, showing that the synthesized toughener emulsion is relatively evenly dispersed and no significant agglomeration phenomenon occurs. The emulsion particles have a regular core-shell spherical structure. This is because the electron cloud densities between the shell layer formed by the hydrophilic ionic groups of polyurethane on the surface of the latex particles and the core layer formed by the hydrophobic groups of acrylate are different, so there is a phenomenon of different shades of color between the edge and the core.

[0059] The results of mechanical tests show that (as shown in Figure 2 ), adding the self-made toughener ( Figure 2 the percentage beside the curve in Figure 2 is the percentage content of the added self-made toughener) to the epoxy resin network can significantly improve the toughness of the epoxy resin. Through dynamic mechanical analysis, it is confirmed that the crosslinking density and glass transition temperature of the epoxy system will decrease after being modified with liquid rubber.

[0060] The physical properties of the solvent-free waterborne polyurethane-acrylate toughener modified epoxy resin waterproof coating prepared in the examples were tested according to the index requirements of JC / T2217-2014. The test results of Example 2 are shown in Table 1.

[0061] Table 1 Test results of the toughener modified epoxy resin waterproof coating

[0062]

[0063] It is easy for those skilled in the art to understand that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A preparation method of a waterborne polyurethane-acrylate toughening agent without organic solvents, characterized in that, Parts by weight The steps are as follows: S1. Add 25 - 50 parts of polyethylene glycol, 30 - 60 parts of isocyanate monomer, 35 - 65 parts of acrylate monomer, and 1 - 5 parts of hydroxyl-terminated polybutadiene into a reaction kettle. Add 0.12 - 0.25 parts of dibutyltin dilaurate at 60 - 80 °C and react for 1.5 - 3 h for standby; S2. Continue to add 1 - 3 parts of small molecule chain extender and 5 - 10 parts of hydrophilic chain extender into the reaction kettle of S1 under the condition of 60 - 80 °C and react for 1.5 - 3 h for standby; In step S2, the small molecule chain extender is one or more of ethylene glycol, 1,4 - butanediol, diethylene glycol, propylene glycol, neopentyl glycol, or 1,6 - hexanediol; In step S2, the hydrophilic chain extender is one of diethanolamine, triethanolamine, N - methyldiethanolamine, dimethylolpropionic acid, or dimethylolbutyric acid; S3. Add 1 - 3 parts of acrylate hydroxyester capping agent to the product obtained in step S2 and react for 1 - 3 h to obtain a polyurethane - acrylate prepolymer for standby; S4. Cool the reaction kettle containing the polyurethane - acrylate prepolymer in step S3 to 30 - 45 °C, add a mixed aqueous solution of 20 - 35 parts of sulfonic acid group post - chain extender and 1 - 2 parts of sodium hydroxide under high - speed stirring for neutralization and emulsification, and then keep warm for 0.3 - 0.6 h; In step S4, the sulfonic acid group post - chain extender has a molecular structure of ； S5. Raise the temperature of the product obtained in step S4 to 70 - 85 °C, dropwise add 0.5 - 1.5 parts of initiator solution, the dropping time is 0.5 - 2 h, and then keep warm for 2 - 4 h to obtain a solvent - free water - borne polyurethane - acrylate toughening agent.

2. The preparation method of the organic solvent-free aqueous polyurethane-acrylate toughening agent according to claim 1, characterized in that In step S1, the polyethylene glycol is polyethylene glycol treated by vacuum dehydration.

3. The preparation method of the organic solvent-free aqueous polyurethane-acrylate toughening agent according to claim 1, characterized in that, In step S1, the isocyanate monomer is isophorone diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, 1,4 - cyclohexane diisocyanate, trimethyl - 1,6 - hexamethylene diisocyanate, or cyclohexane dimethylene diisocyanate.

4. The preparation method of the organic-solvent-free waterborne polyurethane-acrylate toughening agent according to claim 1, wherein, In step S1, the acrylate monomer is one or a mixture of any ratio of two or more of glycidyl methacrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, hexyl methacrylate, n - octyl methacrylate, or 2 - ethylhexyl methacrylate.

5. The preparation method of the organic solvent-free aqueous polyurethane-acrylate toughening agent according to claim 1, wherein, In step S3, the acrylate hydroxyester capping agent is one of hydroxyethyl acrylate, hydroxyethyl methacrylate, or hydroxypropyl acrylate.

6. The preparation method of the organic solvent-free aqueous polyurethane-acrylate toughening agent according to claim 1, wherein, In step S5, the initiator is one of potassium persulfate, ammonium persulfate, or azodiisobutyramidine hydrochloride.

7. A modified epoxy resin waterproof coating, characterized in that, In parts by weight, the coating is divided into two components, A and B. The composition of component A is as follows: 8 - 12 parts of water, 1 - 2 parts of Dow RM - 8W associative thickener, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO₂, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 50 - 80 parts of epoxy resin, 0.05 - 0.15 part of defoamer BYK - 038; The composition of component B is as follows: 1 - 2 parts of thickener, 0.5 - 1 part of dispersant, 5 - 10 parts of TiO₂, 10 - 15 parts of heavy calcium carbonate, 10 - 15 parts of talc powder, 80 - 120 parts of the organic - solvent - free water - borne polyurethane - acrylate toughening agent as described in claim 1, 8 - 10 parts of curing agent, 0.05 - 0.15 part of defoamer.

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