Epoxy resin waterproof coating and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses an epoxy resin waterproof coating and a preparation method thereof. The epoxy resin coating prepared by the invention comprises the following raw materials in parts by weight: 25-35 parts of epoxy resin, 8-15 parts of polyurethane modified epoxy resin, 5-10 parts of fluorine-containing polyether modified polyurea, 3-6 parts of talcum powder, 0.5-1 part of a coupling agent, 0.5-1.5 parts of a flatting agent, 2-5 parts of a dispersing agent, 0.3-1 part of a defoaming agent, 2-4 parts of a reactive diluent, 8-15 parts of a curing agent and 1-3 parts of a curing accelerator. The coating not only has the excellent performance of the traditional epoxy resin coating, but also overcomes the brittleness of the epoxy resin coating, and has excellent impact performance, toughness and waterproof performance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of paint, in particular to an epoxy resin waterproof coating and a preparation method thereof. BACKGROUND

[0002] Epoxy resin waterproof coating is an important high-performance protective material, and its core technology lies in the use of the excellent adhesion, chemical stability and film-forming density of epoxy resin itself. The cured epoxy resin can form a hard and corrosion-resistant three-dimensional cross-linked network, which has good barrier effect on water, oxygen and various chemical media, and is widely used in the waterproof and moisture-proof fields of buildings, bridges, underground engineering and industrial facilities.

[0003] However, the traditional epoxy resin waterproof coating has two key performance short boards: firstly, the cured product usually has high cross-linking density and poor molecular chain segment movement ability, resulting in large brittleness, insufficient flexibility and impact resistance of the coating, and micro-cracks are easily generated under the deformation of the base layer or external force impact, thereby causing leakage; secondly, the surface energy of the cured epoxy resin coating is high and has hydrophilic properties, resulting in a low static water contact angle, and the performance will gradually decrease in long-term water immersion or humid environment. Therefore, in view of the existing problems of epoxy resin at present, it is necessary to develop an epoxy resin coating with excellent toughness, impact resistance and waterproofness to meet the actual application requirements. SUMMARY

[0004] In order to solve the above technical problems, the present application provides an epoxy resin waterproof coating and a preparation method thereof.

[0005] The object of the present application can be achieved by the following technical solutions: An epoxy resin waterproof coating comprises the following raw materials by weight: 25-35 parts of epoxy resin, 8-15 parts of polyurethane modified epoxy resin, 5-10 parts of fluorine-containing polyether modified polyurea, 3-6 parts of talcum powder, 0.5-1 part of coupling agent, 0.5-1.5 parts of leveling agent, 2-5 parts of dispersing agent, 0.3-1 part of defoaming agent, 2-4 parts of active diluent, 8-15 parts of curing agent and 1-3 parts of curing accelerator. The coupling agent is one of silane coupling agent or titanate coupling agent; The leveling agent is one of BYK-310 or BYK-333; The dispersing agent is glycerol diglycidyl ether; The defoaming agent is one of BYK-052N or BYK-085; The active diluent is one of polypropylene glycol diglycidyl ether or ethylene glycol diglyceryl ether; The curing agent is one of amine curing agent; The curing accelerator is one of the imidazole curing accelerators; The fluorinated polyether-modified polyurea is prepared by the following steps: Step A1: Place N-(2-aminoethyl)glycine and polytetrahydrofurandiol in a flask, stir evenly under an ice-water bath, then slowly add 98wt% concentrated sulfuric acid, and maintain the ice-water bath conditions for 3-4 hours. Then react at room temperature for 24 hours. After the reaction is completed, add saturated sodium bicarbonate solution and stir for 20-40 minutes. Filter under reduced pressure, wash, and dry to obtain the terminal amino polyether segments. Further, in step A1, the ratio of N-(2-aminoethyl)glycine, polytetrahydrofurandiol, concentrated sulfuric acid, and saturated sodium bicarbonate solution is 0.02-0.03 mol: 0.01 mol: 1-1.5 mL: 150 mL; Further, the polytetrahydrofuran diol mentioned in step A1 is HO[CH2CH2CH2CH2O]. n H, and n=3; Step A2: Toluene 2,6-diisocyanate and amino-terminated polyether segments are stirred evenly in tetrahydrofuran and labeled as solution 1 and solution 2, respectively. Solution 2 is slowly added to solution 1 and stirred at 45°C under nitrogen for 3-4 hours. Then, the temperature is raised to 60°C, dibutyltin dilaurate is added, and the reaction is continued with stirring for 6-8 hours. The mixture is then distilled under reduced pressure to obtain polyether-modified polyurea. Further, in step A2, the molar ratio of the isocyanate group in 2,6-diisocyanate toluene to the amino group in the amino-terminated polyether segment is 1.1-1.3:1, and the molar amount of dibutyltin dilaurate is 0.6%-0.8% of the molar amount of 2,6-diisocyanate toluene. Step A3: Dissolve the polyether-modified polyurea and 1H,1H,2H,2H-perfluorooctyl acrylate separately in a mixture of methanol and water, and stir them evenly. Then, pour them into a flask under nitrogen and stir evenly. Place the flask in a 60°C oil bath and stir for 2-3 hours. Purify by vacuum distillation to obtain fluorinated polyether-modified polyurea. Furthermore, in step A3, the molar ratio of polyether-modified polyurea and 1H,1H,2H,2H-perfluorooctyl acrylate is 1:1.5-2.5; Furthermore, in step A3, the volume ratio of methanol and water in the mixture is 1:1.

[0006] A method for preparing an epoxy resin waterproof coating includes the following steps: Weigh the raw materials according to the weight proportions, add epoxy resin, polyurethane modified epoxy resin, fluorinated polyether modified polyurea, leveling agent, dispersant, and reactive diluent to a mixer, and stir evenly at a speed of 250-450 rpm / min. Then add talc powder and defoamer, and stir at a speed of 500-700 rpm / min for 30 minutes. After that, let it stand for 2 hours, then add curing agent and curing accelerator and stir evenly. Store at room temperature to obtain epoxy resin waterproof coating.

[0007] The beneficial effects of this invention are: The epoxy resin coating prepared by this invention is made by adding fluorinated polyether modified polyurea, leveling agent, dispersant, reactive diluent, talc and other functional additives as the main matrix resins. The coating not only has the excellent properties of traditional epoxy resin coatings, but also overcomes the brittleness of epoxy resin coatings, and has excellent impact resistance, toughness and waterproof performance.

[0008] The fluorinated polyether-modified polyurea introduced into the coating of this invention firstly improves the crosslinking density and impact resistance of the coating film by utilizing the synergistic effect of the polyether structure, polyurea structure, and benzene ring structure in its main chain. This is because the polyurea structure (-NH-CO-NH-) in the main chain can form a dense hydrogen bond network. Under impact, the hydrogen bonds can reversibly break and recombine, effectively absorbing and dispersing energy, reducing stress concentration, and thus significantly improving the toughness and impact strength of the coating film. Meanwhile, the ether bonds (-O-) in the polyether structure endow the main chain with high flexibility and rotational freedom, enabling the coating film to withstand stress. It undergoes elastic deformation to absorb impact energy, while the benzene ring structure in the main chain and epoxy resin provides rigid support, enhancing the modulus and tensile strength of the coating film, preventing excessive deformation, and forming a "rigid-flexible" system with the flexible chain segments, balancing strength and toughness; the secondary amine groups (-NH-) and free isocyanate groups (-NCO) in the main chain can also undergo ring-opening reactions with the epoxy groups of the epoxy resin to form chemical crosslinks, enhancing the interfacial bonding between the fluorinated polyether modified polyurea and the epoxy resin matrix, forming a stable three-dimensional network structure, reducing defects, and improving overall load-bearing capacity and durability. Secondly, fluorinated segments are introduced into the side chains of fluorinated polyether-modified polyurea. These segments can work synergistically with talc, which has a lamellar structure, to improve the waterproof performance of the coating. This is because fluorinated segments (such as -CF3 or -CF2-) have extremely low surface energy. During the curing process of the coating, these hydrophobic segments tend to migrate to the surface of the coating to form a dense low surface energy layer. This layer can significantly reduce the coating's affinity for water, making it difficult for water droplets to spread, thereby producing a high water contact angle and excellent waterproof performance. Meanwhile, talc can use its lamellar structure to exert a physical effect in the coating to prevent water penetration, thereby improving the waterproof effect of the coating. Detailed Implementation

[0009] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0010] Example 1: Fluorinated polyether modified polyurea was prepared by the following steps: Step A1: Place 0.02 mol N-(2-aminoethyl)glycine and 0.01 mol polytetrahydrofurandiol in a flask, stir evenly under an ice-water bath, then slowly add 1 mL of 98 wt% concentrated sulfuric acid, maintaining the ice-water bath conditions for 3 hours, and then react at room temperature for 24 hours. After the reaction is complete, add 150 mL of saturated sodium bicarbonate solution and stir for 20 minutes. Filter under reduced pressure, wash, and dry to obtain the amino-terminated polyether segments. The polytetrahydrofurandiol is HO[CH2CH2CH2CH2O]. n H, and n=3; Step A2: 1.1 mol of 2,6-diisocyanate toluene and 1 mol of amino-terminated polyether segments were stirred evenly in 100 mL of tetrahydrofuran, and labeled as solution 1 and solution 2, respectively. Solution 2 was slowly added to solution 1, and the mixture was stirred at 45 °C under nitrogen for 3 h. Then, the temperature was raised to 60 °C, and dibutyltin dilaurate was added. The reaction was continued with stirring for 6 h. The mixture was then distilled under reduced pressure to obtain polyether-modified polyurea. The molar amount of dibutyltin dilaurate was 0.6% of the molar amount of 2,6-diisocyanate toluene. Step A3: Dissolve 1 mol of polyether-modified polyurea and 1.5 mol of 1H,1H,2H,2H-perfluorooctyl acrylate in a mixture of 50 mL of methanol and 50 mL of water, respectively, and stir them evenly. Then, pour them into a flask under nitrogen atmosphere and stir evenly. Place the flask in a 60℃ oil bath and stir for 2 hours. Purify by vacuum distillation to obtain fluorinated polyether-modified polyurea.

[0011] Example 2: Fluorinated polyether modified polyurea was prepared by the following steps: Step A1: Place 0.025 mol N-(2-aminoethyl)glycine and 0.01 mol polytetrahydrofurandiol in a flask, stir evenly under an ice-water bath, then slowly add 1.3 mL of 98 wt% concentrated sulfuric acid, maintaining the ice-water bath conditions for 3.5 h, and then react at room temperature for 24 h. After the reaction is complete, add 150 mL of saturated sodium bicarbonate solution and stir for 30 min. Filter under reduced pressure, wash, and dry to obtain the amino-terminated polyether segments. The polytetrahydrofurandiol is HO[CH2CH2CH2CH2O]. n H, and n=3; Step A2: 1.2 mol of 2,6-diisocyanate toluene and 1 mol of amino-terminated polyether segments were stirred evenly in 100 mL of tetrahydrofuran, and labeled as solution 1 and solution 2, respectively. Solution 2 was slowly added to solution 1, and the mixture was stirred at 45 °C under nitrogen for 3.5 h. Then, the temperature was raised to 60 °C, and dibutyltin dilaurate was added. The reaction was continued with stirring for 7 h. The mixture was then distilled under reduced pressure to obtain polyether-modified polyurea. The molar amount of dibutyltin dilaurate was 0.7% of the molar amount of 2,6-diisocyanate toluene. Step A3: Dissolve 1 mol of polyether-modified polyurea and 2 mol of 1H,1H,2H,2H-perfluorooctyl acrylate in a mixture of 50 mL of methanol and 50 mL of water, respectively, and stir them evenly. Then, pour them into a flask under nitrogen atmosphere and stir evenly. Place the flask in a 60℃ oil bath and stir for 2.5 h. Purify by vacuum distillation to obtain fluorinated polyether-modified polyurea.

[0012] Example 3: Fluorinated polyether modified polyurea was prepared by the following steps: Step A1: Place 0.03 mol N-(2-aminoethyl)glycine and 0.01 mol polytetrahydrofuran diol in a flask, stir evenly under an ice-water bath, then slowly add 1.5 mL of 98 wt% concentrated sulfuric acid, maintaining the ice-water bath conditions for 4 hours, and then react at room temperature for 24 hours. After the reaction is complete, add 150 mL of saturated sodium bicarbonate solution and stir for 40 minutes. Filter under reduced pressure, wash, and dry to obtain the amino-terminated polyether segments. The polytetrahydrofuran diol is HO[CH2CH2CH2CH2O]. n H, and n=3; Step A2: 1.3 mol of 2,6-diisocyanate toluene and 1 mol of amino-terminated polyether segments were stirred evenly in 100 mL of tetrahydrofuran, and labeled as solution 1 and solution 2, respectively. Solution 2 was slowly added to solution 1, and the mixture was stirred at 45 °C under nitrogen for 4 h. Then, the temperature was raised to 60 °C, and dibutyltin dilaurate was added. The reaction was continued with stirring for 8 h. The mixture was then distilled under reduced pressure to obtain polyether-modified polyurea. The molar amount of dibutyltin dilaurate was 0.8% of the molar amount of 2,6-diisocyanate toluene. Step A3: Dissolve 1 mol of polyether-modified polyurea and 2.5 mol of 1H,1H,2H,2H-perfluorooctyl acrylate in a mixture of 50 mL of methanol and 50 mL of water, respectively, and stir them evenly. Then, pour them into a flask under nitrogen atmosphere and stir evenly. Place the flask in a 60℃ oil bath and stir for 3 hours. Purify by vacuum distillation to obtain fluorinated polyether-modified polyurea.

[0013] Example 4: A method for preparing an epoxy resin waterproof coating includes the following steps: 25 parts epoxy resin, 8 parts polyurethane modified epoxy resin, 5 parts fluorinated polyether modified polyurea prepared in Example 1, 3 parts talc, 0.5 parts coupling agent (silane coupling agent KH550), 0.5 parts leveling agent (BYK-310), 2 parts dispersant (glyceryl diglycidyl ether), 0.3 parts defoamer (BYK-052N), 2 parts reactive diluent (polypropylene glycol diglycidyl ether), 8 parts curing agent (ethylenediamine), and 1 part curing accelerator (2-ethylimidazole). Weigh the raw materials according to the weight parts, add epoxy resin, polyurethane modified epoxy resin, fluorinated polyether modified polyurea prepared in Example 1, leveling agent, dispersant, and reactive diluent into a stirrer, stir evenly at a speed of 250 rpm / min, then add talc powder and defoamer, stir at a speed of 500 rpm / min for 30 min, then let stand for 2 h, then add curing agent and curing accelerator and stir evenly, store at room temperature to obtain epoxy resin waterproof coating.

[0014] Example 5: A method for preparing an epoxy resin waterproof coating includes the following steps: 30 parts epoxy resin, 12 parts polyurethane modified epoxy resin, 7 parts fluorinated polyether modified polyurea prepared in Example 2, 4.5 parts talc, 0.8 parts coupling agent (titanium ester coupling agent GR-311W), 1 part leveling agent (BYK-333), 3.5 parts dispersant (glyceryl diglycidyl ether), 0.6 parts defoamer (BYK-085), 3 parts reactive diluent (ethylene glycol diglycerol ether), 12 parts curing agent (diethylenetriamine), and 2 parts curing accelerator (2-methylimidazole); Weigh the raw materials according to the weight parts, add epoxy resin, polyurethane modified epoxy resin, fluorinated polyether modified polyurea prepared in Example 2, leveling agent, dispersant, and reactive diluent into a stirrer, stir evenly at a speed of 350 rpm / min, then add talc powder and defoamer, stir at a speed of 600 rpm / min for 30 min, then let stand for 2 h, then add curing agent and curing accelerator and stir evenly, store at room temperature to obtain epoxy resin waterproof coating.

[0015] Example 6: A method for preparing an epoxy resin waterproof coating includes the following steps: 35 parts epoxy resin, 15 parts polyurethane modified epoxy resin, 10 parts fluorinated polyether modified polyurea prepared in Example 3, 6 parts talc, 1 part coupling agent (silane coupling agent KH570), 1.5 parts leveling agent (BYK-310), 5 parts dispersant (glyceryl diglycidyl ether), 1 part defoamer (BYK-052N), 4 parts reactive diluent (polypropylene glycol diglycidyl ether), 15 parts curing agent (triethylenetetramine), and 3 parts curing accelerator (2-ethylimidazole). Weigh the raw materials according to the weight parts, add epoxy resin, polyurethane modified epoxy resin, fluorinated polyether modified polyurea prepared in Example 3, leveling agent, dispersant, and reactive diluent into a stirrer, stir evenly at a speed of 450 rpm / min, then add talc powder and defoamer, stir at a speed of 700 rpm / min for 30 min, then let stand for 2 h, then add curing agent and curing accelerator and stir evenly, store at room temperature to obtain epoxy resin waterproof coating.

[0016] Comparative Example 1: This comparative example is an epoxy resin waterproof coating. The difference between this example and Example 6 is that the fluorinated polyether modified polyurea prepared in Example 3 was not added. All other aspects are the same.

[0017] Comparative Example 2: This comparative example is an epoxy resin waterproof coating. The difference between this example and Example 6 is that the polyether-modified polyurea prepared in Example 3 is used instead of the fluorinated polyether-modified polyurea prepared in Example 3. All other aspects are the same.

[0018] Comparative Example 3: This comparative example is an epoxy resin waterproof coating. The difference between this example and Example 6 is that no talc powder was added. All other aspects are the same.

[0019] The epoxy resin waterproof coatings prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests: Impact strength test: Impact performance was tested according to standard GB / T 1732-2020 "Determination of Impact Resistance of Coating Films"; Contact angle test: The water contact angle of the coating was tested using a TC-A3 automatic contact angle measuring instrument; Waterproof performance test: Multiple glass slides loaded with the coating were immersed in clean water for 10, 20, 30 and 40 days respectively, and the changes on the coating surface of the glass slides were observed. The test results are shown in Table 1: Table 1: Performance Test Results

[0020] As can be seen from Table 1, the epoxy resin waterproof coating prepared by this invention not only has excellent impact strength, but also has low surface energy and exhibits a high water contact angle; after waterproof performance testing, the coated surface showed no blistering or damage, demonstrating excellent waterproof performance.

[0021] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the scope defined by the inventive concept, they should all fall within the protection scope of the present invention.

Claims

1. An epoxy resin waterproof coating, characterized in that, The raw materials include the following parts by weight: 25-35 parts epoxy resin, 8-15 parts polyurethane modified epoxy resin, 5-10 parts fluorinated polyether modified polyurea, 3-6 parts talc, 0.5-1 part coupling agent, 0.5-1.5 parts leveling agent, 2-5 parts dispersant, 0.3-1 part defoamer, 2-4 parts reactive diluent, 8-15 parts curing agent, and 1-3 parts curing accelerator. The fluorinated polyether modified polyurea is prepared by reacting polyether modified polyurea and 1H,1H,2H,2H-perfluorooctyl acrylate under nitrogen at 60°C for 2-3 hours; the polyether modified polyurea is prepared by reacting 2,6-diisocyanate toluene and amino-terminated polyether segments under nitrogen at 45°C for 3-4 hours, followed by a reaction at 60°C for 6-8 hours; the polyether modified polyurea is prepared by reacting N-(2-aminoethyl)glycine and polytetrahydrofuran diol under 98wt% concentrated sulfuric acid in an ice-water bath for 3-4 hours, followed by a reaction at room temperature for 24 hours.

2. The epoxy resin waterproof coating according to claim 1, characterized in that, The fluorinated polyether-modified polyurea is prepared by the following steps: Step A1: Place N-(2-aminoethyl)glycine and polytetrahydrofurandiol in a flask, stir evenly under an ice-water bath, then slowly add 98wt% concentrated sulfuric acid, and maintain the ice-water bath conditions for 3-4 hours. Then react at room temperature for 24 hours. After the reaction is completed, add saturated sodium bicarbonate solution and stir for 20-40 minutes. Filter under reduced pressure, wash, and dry to obtain the terminal amino polyether segments. Step A2: Toluene 2,6-diisocyanate and amino-terminated polyether segments are stirred evenly in tetrahydrofuran and labeled as solution 1 and solution 2, respectively. Solution 2 is slowly added to solution 1 and stirred at 45°C under nitrogen for 3-4 hours. Then, the temperature is raised to 60°C, dibutyltin dilaurate is added, and the reaction is continued with stirring for 6-8 hours. The mixture is then distilled under reduced pressure to obtain polyether-modified polyurea. Step A3: Dissolve the polyether-modified polyurea and 1H,1H,2H,2H-perfluorooctyl acrylate separately in a mixture of methanol and water, and stir them evenly. Then, pour them into a flask under nitrogen and stir evenly. Place the flask in a 60°C oil bath and stir for 2-3 hours. Purify by vacuum distillation to obtain the fluorinated polyether-modified polyurea.

3. The epoxy resin waterproof coating according to claim 2, characterized in that, In step A1, the ratio of N-(2-aminoethyl)glycine, polytetrahydrofurandiol, concentrated sulfuric acid, and saturated sodium bicarbonate solution is 0.02-0.03 mol: 0.01 mol: 1-1.5 mL: 150 mL.

4. The epoxy resin waterproof coating according to claim 2, characterized in that, The polytetrahydrofuran diol mentioned in step A1 is HO[CH2CH2CH2CH2O]. n H, and n=3.

5. The epoxy resin waterproof coating according to claim 2, characterized in that, In step A2, the molar ratio of isocyanate groups in 2,6-diisocyanate toluene to the amino groups in the amino-terminated polyether segments is 1.1-1.3:1, and the molar amount of dibutyltin dilaurate is 0.6%-0.8% of the molar amount of 2,6-diisocyanate toluene.

6. The epoxy resin waterproof coating according to claim 2, characterized in that, In step A3, the molar ratio of polyether-modified polyurea and 1H,1H,2H,2H-perfluorooctyl acrylate is 1:1.5-2.5, and the volume ratio of the two in the methanol and water mixture is 1:

1.

7. The epoxy resin waterproof coating according to claim 1, characterized in that, The coupling agent is one of a silane coupling agent or a titanate coupling agent, the leveling agent is one of BYK-310 or BYK-333, and the dispersant is glycerol diglycidyl ether.

8. The epoxy resin waterproof coating according to claim 1, characterized in that, The defoamer is either BYK-052N or BYK-085, and the active diluent is either polypropylene glycol diglycidyl ether or ethylene glycol diglycidyl ether.

9. The epoxy resin waterproof coating according to claim 1, characterized in that, The curing agent is a type of amine curing agent, and the curing accelerator is a type of imidazole curing accelerator.

10. A method for preparing the epoxy resin waterproof coating according to any one of claims 1-9, characterized in that, Includes the following steps: Weigh the raw materials according to the weight proportions, add epoxy resin, polyurethane modified epoxy resin, fluorinated polyether modified polyurea, leveling agent, dispersant, and reactive diluent to a mixer, and stir evenly at a speed of 250-450 rpm / min. Then add talc powder and defoamer, and stir at a speed of 500-700 rpm / min for 30 minutes. After that, let it stand for 2 hours, then add curing agent and curing accelerator and stir evenly. Store at room temperature to obtain epoxy resin waterproof coating.

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