Polyurea waterproof coating and preparation method thereof

Abstract

This invention relates to the field of coating technology and discloses a polyurea waterproof coating and its preparation method, comprising the following weight components: 40-50 parts by weight of polyurea resin, 3-5 parts by weight of fluorine-modified bamboo powder, 0.2-0.4 parts by weight of BYK-071 defoamer, and 0.1-0.3 parts by weight of BYK-345 leveling agent; the preparation method of the fluorine-modified bamboo powder is as follows: Step 1: reacting bamboo powder with KH-550 to obtain coupling agent-modified bamboo powder; Step 2: reacting the coupling agent-modified bamboo powder with perfluorooctanoyl chloride under the action of triethylamine catalyst to obtain fluorine-modified bamboo powder. The polyurea waterproof coating prepared by this invention has good waterproof and self-healing effects.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a polyurea waterproof coating and its preparation method. Background Technology

[0002] In the field of coating technology, polyurea waterproof coatings are widely used for waterproofing and protection in building roofs, underground projects, and water conservancy facilities due to their fast curing speed, excellent mechanical properties, and strong weather resistance. However, existing polyurea waterproof coatings still have many technical problems in practical applications, making it difficult to meet market demands. Specific problems include: 1. Existing polyurea waterproof coatings, once cracked or damaged by external impacts or substrate deformation, cannot repair defects on their own, requiring manual touch-up and maintenance. This not only increases construction costs but may also lead to substrate corrosion and structural damage if repairs are not timely. 2. Traditional polyurea waterproof coatings often rely on a single resin matrix to construct the waterproof structure, resulting in insufficient density between molecular chains. With prolonged exposure to water, water molecules can easily penetrate the substrate through micropores or intermolecular gaps, leading to waterproofing failure. Therefore, avoiding these phenomena is key to solving the problem. Summary of the Invention

[0003] Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a polyurea waterproof coating and its preparation method, which has good waterproof, self-healing, and weather resistance properties.

[0004] Technical solution To achieve the above objectives, the present invention provides the following technical solution: a polyurea waterproof coating, comprising the following weight components: 40-50 parts by weight of polyurea resin, 3-5 parts by weight of fluorine-modified bamboo powder, 0.2-0.4 parts by weight of BYK-071 defoamer, and 0.1-0.3 parts by weight of BYK-345 leveling agent; The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: React bamboo powder with KH-550 to obtain coupling agent modified bamboo powder; Step 2: The coupling agent-modified bamboo powder and perfluorooctanoyl chloride are reacted under the action of triethylamine catalyst to obtain fluorine-modified bamboo powder.

[0005] Furthermore, the preparation method of the polyurea resin is as follows: S1. Under a nitrogen atmosphere, N,N,N'-trimethylethylenediamine and 4,4'-difluorodiphenyl sulfone were added to N-methylpyrrolidone solvent, anhydrous potassium carbonate was added as a catalyst, and the reaction was carried out at 160-170℃ for 4-5 h. After the reaction, the mixture was filtered and dried to obtain intermediate 1. S2. Add intermediate 1 and 2-chloroethanol to N,N-dimethylformamide solvent, stir and mix, react at 65-70℃ for 2-4 hours, after which rotary distillation and filtration are performed to obtain sulfone chain extender. S3. Add 2-3 mmol of polytetrahydrofuran ether glycol, 2-4 g of polypropylene glycol, and N,N-dimethylformamide solvent to a reaction flask, dehydrate at 115-120℃ for 1.5-2 h, cool to 50-55℃, and continue to add 4-6.5 mmol of isophorone diisocyanate and 0.1-0.12 mmol of dibutyltin dilaurate. Heat to 85-90℃ and react for 2-3 h, cool to 50-60℃, and then continue to add 0.5-0.7 mmol of dithiobis(p-amino)benzene and 0.5-0.6 mmol of sulfone chain extender. React for 40-50 min, and after completion, polyurea resin is obtained.

[0006] Furthermore, in S1, the ratio of N,N,N'-trimethylethylenediamine, 4,4'-difluorodiphenyl sulfone, and anhydrous potassium carbonate is 2-4 mmol: 1-2 mmol: 0.1-0.2 mmol.

[0007] Furthermore, in S2, the molar ratio of intermediate 1 to 2-chloroethanol is 1.2-1.6 mmol: 4.8-6.5 mmol.

[0008] Furthermore, in S3, the molecular weights of polytetrahydrofuran ether diol and polypropylene glycol are 2000.

[0009] Furthermore, the preparation method of the fluorine-modified bamboo powder is as follows: Step 1: Add 2-3g of bamboo powder to a reaction flask containing 0.1-0.15g of KH-550, heat to 160-180℃ and react for 1-2 hours, then let stand for 40-48 hours. After the reaction is complete, filter, dry, disperse in acetone, stir, filter and wash again to obtain coupling agent modified bamboo powder. Step 2: Add the coupling agent-modified bamboo powder and perfluorooctanoic acid chloride to N,N-dimethylformamide solvent, stir and mix, add triethylamine catalyst, react at 25-35℃ for 2-3 hours, after which vacuum distillation, washing, and drying are carried out to obtain fluorine-modified bamboo powder.

[0010] Furthermore, in step two, the ratio of the coupling agent modified bamboo powder, perfluorooctanoyl chloride, and triethylamine is 1.4-2 mmol: 0.64-0.9 g: 0.01-0.02 g.

[0011] Furthermore, the preparation method of the polyurea waterproof coating is as follows: polyurea resin, fluorine-modified bamboo powder, BYK-071 defoamer, and BYK-345 leveling agent are added to a stirrer and stirred for 20-30 minutes to obtain the polyurea waterproof coating.

[0012] Beneficial technical effects In the preparation of polyurea resin, the synergistic effect of sulfone-based chain extenders and disulfide di(p-amino)benzene constructs cross-linked molecular chains containing sulfone groups and disulfide bonds, further enhancing the compactness and water resistance of the resin matrix. This invention introduces fluorine-modified bamboo powder as a functional filler. After modification with KH-550 coupling agent, the surface amino groups of the bamboo powder form chemical bonds with the polyurea resin. Then, fluorine atoms are introduced through perfluorooctanoyl chloride modification. The low surface energy of fluorine forms a hydrophobic barrier on the coating surface. Simultaneously, the synergistic effect of fluorine-modified bamboo powder and the resin matrix densifies the molecular structure, effectively blocking the penetration pathways of water molecules.

[0013] The disulfide bonds (-SS-) in polyurea resin possess dynamic reversible properties, capable of breaking and recombinizing under external stimuli. When cracks appear in the coating layer, the disulfide bonds can autonomously repair molecular chain defects. Simultaneously, the fibrous structure of fluorinated bamboo powder can form a "physical bridge" at the crack, helping to prevent crack propagation. Furthermore, the polyurea resin molecular chain contains a large number of -NH- bonds, and the surface of fluorinated bamboo powder is modified with perfluorooctanoic acid (PFOA) to introduce -CF bonds, forming strong hydrogen bonds. This preserves the reversibility of hydrogen bonds; when damaged, the hydrogen bonds break, and when repaired, they recombine, further enhancing self-healing efficiency.

[0014] As a natural and renewable resource, bamboo powder not only reduces the production cost of coatings compared to traditional inorganic fillers, but also reduces the environmental pollution caused by inorganic fillers, which is in line with the trend of green and environmentally friendly development.

[0015] The polyurea waterproof coating prepared by this invention integrates waterproof performance, self-healing ability, mechanical properties and weather resistance, and has good market application prospects. Attached Figure Description

[0016] Figure 1 This is the reaction formula for the sulfone-based chain extender in Example 1. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, 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.

[0018] To better understand the above technical solutions, the following will provide a detailed description of the technical solutions in conjunction with the accompanying drawings and specific embodiments.

[0019] Bamboo powder with a particle size <180μm should be dried before use: dry in a 120℃ forced-air drying oven for 5 hours; silane coupling agent: γ-aminopropyltriethoxysilane (KH-550), commercially available. Tetrahydrofuran ether diol (Mw=2000), polypropylene glycol (Mw=2000).

[0020] Example 1 A method for preparing a polyurea waterproof coating includes the following steps: Add 40 parts by weight of polyurea resin, 3 parts by weight of fluorine-modified bamboo powder, 0.2 parts by weight of BYK-071 defoamer, and 0.1 parts by weight of BYK-345 leveling agent to a mixer and stir for 20 minutes to obtain a polyurea waterproof coating. The preparation method of the polyurea resin is as follows: S1. Under a nitrogen atmosphere, 2 mmol of N,N,N'-trimethylethylenediamine (CAS:142-25-6) and 1 mmol of 4,4'-difluorodiphenyl sulfone (CAS:383-29-9) were added to 35 mL of N-methylpyrrolidone solvent. 0.1 mmol of anhydrous potassium carbonate was added as a catalyst, and the reaction was carried out at 160 °C for 4 h. After the reaction, the mixture was filtered and dried to obtain intermediate 1. S2. Add 1.2 mmol of intermediate 1 and 4.8 mmol of 2-chloroethanol to 30 mL of N,N-dimethylformamide solvent, stir and mix, react at 65 °C for 2 h, and after the reaction is completed, rotary distill and filter to obtain sulfone chain extender. S3. Add 2 mmol of polytetrahydrofuran ether diol-2000, 2 g of polypropylene glycol-2000, and 20 mL of N,N-dimethylformamide solvent to a reaction flask. Dehydrate at 115°C for 1.5 h, cool to 50°C, and then add 4 mmol of isophorone diisocyanate and 0.1 mmol of dibutyltin dilaurate. Heat to 85°C and react for 2 h, then cool to 50°C. Then add 0.5 mmol of dithiobis(p-amino)benzene and 0.5 mmol of sulfone chain extender and react for 40-50 min. After the reaction is complete, polyurea resin is obtained.

[0021] The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: Add 2g of bamboo powder to a reaction flask containing 0.1g of KH-550, heat to 160℃ and react for 1-2 hours, then let stand for 40 hours. After the reaction is complete, filter, dry, and disperse in acetone. Stir, filter again, and wash to obtain coupling agent modified bamboo powder. Step 2: Add 1.4 mmol of coupling agent-modified bamboo powder and 0.64 g of perfluorooctanoic acid chloride to 30 mL of N,N-dimethylformamide solvent, stir and mix, add 0.01 g of triethylamine catalyst, react at 25 °C for 2 h, after which vacuum distillation, washing, and drying are performed to obtain fluorine-modified bamboo powder.

[0022] Example 2 A method for preparing a polyurea waterproof coating includes the following steps: Add 50 parts by weight of polyurea resin, 5 parts by weight of fluorine-modified bamboo powder, 0.4 parts by weight of BYK-071 defoamer, and 0.3 parts by weight of BYK-345 leveling agent to a mixer and stir for 30 minutes to obtain a polyurea waterproof coating. The preparation method of the polyurea resin is as follows: S1. Under a nitrogen atmosphere, 4 mmol of N,N,N'-trimethylethylenediamine and 2 mmol of 4,4'-difluorodiphenyl sulfone were added to 40 mL of N-methylpyrrolidone solvent. 0.2 mmol of anhydrous potassium carbonate was added as a catalyst, and the reaction was carried out at 170 °C for 5 h. After the reaction, the mixture was filtered and dried to obtain intermediate 1. S2. Add 1.6 mmol of intermediate 1 and 6.5 mmol of 2-chloroethanol to 35 mL of N,N-dimethylformamide solvent, stir and mix, react at 70 °C for 4 h, and after the reaction is completed, rotary distill and filter to obtain sulfone chain extender. S3. Add 3 mmol of polytetrahydrofuran ether glycol-2000, 4 g of polypropylene glycol-2000, and 30 mL of N,N-dimethylformamide solvent to a reaction flask. Dehydrate at 120°C for 2 h, cool to 55°C, and then add 6.5 mmol of isophorone diisocyanate and 0.12 mmol of dibutyltin dilaurate. Heat to 90°C and react for 3 h, then cool to 60°C. Then add 0.7 mmol of dithiobis(p-amino)benzene and 0.6 mmol of sulfone chain extender and react for 50 min. After the reaction is complete, polyurea resin is obtained.

[0023] The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: Add 2g of bamboo powder to a reaction flask containing 0.1g of KH-550, heat to 160℃ and react for 1 hour, then let stand for 40 hours. After the reaction is complete, filter, dry, and disperse in acetone. Stir, filter again, and wash to obtain coupling agent modified bamboo powder. Step 2: Add 1.4 mmol of coupling agent-modified bamboo powder and 0.64 g of perfluorooctanoic acid chloride to 30 mL of N,N-dimethylformamide solvent, stir and mix, add 0.01 g of triethylamine catalyst, react at 25 °C for 2 h, after which vacuum distillation, washing, and drying are performed to obtain fluorine-modified bamboo powder.

[0024] Example 3 A method for preparing a polyurea waterproof coating includes the following steps: Add 45 parts by weight of polyurea resin, 4 parts by weight of fluorine-modified bamboo powder, 0.3 parts by weight of BYK-071 defoamer, and 0.2 parts by weight of BYK-345 leveling agent to a mixer and stir for 25 minutes to obtain a polyurea waterproof coating. The preparation method of the polyurea resin is as follows: S1. Under a nitrogen atmosphere, 3 mmol of N,N,N'-trimethylethylenediamine and 1.5 mmol of 4,4'-difluorodiphenyl sulfone were added to 37 mL of N-methylpyrrolidone solvent, and 0.15 mmol of anhydrous potassium carbonate was added as a catalyst. The reaction was carried out at 165 °C for 4 h. After the reaction, the mixture was filtered and dried to obtain intermediate 1. S2. Add 1.4 mmol of intermediate 1 and 6.2 mmol of 2-chloroethanol to 32 mL of N,N-dimethylformamide solvent, stir and mix, react at 68 °C for 3 h, and after the reaction is completed, rotary distill and filter to obtain sulfone chain extender; S3. Add 2.5 mmol of polytetrahydrofuran ether diol-2000, 3 g of polypropylene glycol-2000, and 25 mL of N,N-dimethylformamide solvent to a reaction flask. Dehydrate at 117 °C for 1.8 h, cool to 52 °C, and then add 5.25 mmol of isophorone diisocyanate and 0.11 mmol of dibutyltin dilaurate. Heat to 88 °C and react for 2.5 h, then cool to 55 °C. Then add 0.6 mmol of dithiobis(p-amino)benzene and 0.55 mmol of sulfone chain extender and react for 45 min. After the reaction is complete, polyurea resin is obtained.

[0025] The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: Add 2.5g of bamboo powder to a reaction flask containing 0.12g of KH-550, heat to 170℃ and react for 1 hour, then let stand for 44 hours. After the reaction is complete, filter, dry, disperse in acetone, stir, filter and wash again to obtain coupling agent modified bamboo powder. Step 2: Add 1.8 mmol of coupling agent-modified bamboo powder and 0.75 g of perfluorooctanoic acid chloride to 35 mL of N,N-dimethylformamide solvent, stir and mix, add 0.015 g of triethylamine catalyst, react at 30 °C for 2 h, after which vacuum distillation, washing, and drying are performed to obtain fluorine-modified bamboo powder.

[0026] Comparative Example 1 The difference between this comparative example and Example 3 is that bamboo powder was used instead of fluorine-modified bamboo powder.

[0027] Comparative Example 2 The difference between this comparative example and Example 3 is that no sulfone-based chain extender was added.

[0028] Comparative Example 3 The difference between this comparative example and Example 3 is that dithiobis(p-amino)benzene was not added.

[0029] Performance testing Hydrophobicity test: Tested using a contact angle tester; Weather resistance test standard: Tested according to GB / T14522-2008; Repair test: Scratch-repair test conducted on different coating surfaces. A 50 μm deep scratch was made on the coatings of the examples and comparative examples using a sharp scalpel blade, and the damaged material was then placed in air at room temperature (25°C) for repair. The healing of the scratch on the coating surface was observed at intervals using an optical microscope, and the required repair time was recorded.

[0030] Table 1: Weather Resistance and Repair Tests Example 1 148.2 8.2 No bubbles, no cracks Example 2 150.6 7.8 No bubbles, no cracks Example 3 152.5 7.6 No bubbles, no cracks Comparative Example 1 135.4 9.3 No bubbles, slightly cracked Comparative Example 2 145.1 9.2 No bubbles, slightly cracked Comparative Example 3 146.3 9.7 No bubbles, slightly cracked As shown in Table 1, the polyurea waterproof coating of the present invention has good self-healing, hydrophobic, and weather-resistant effects. Comparative Example 1 (unmodified bamboo powder instead of fluorinated bamboo powder): hydrophobicity decreased because the surface of unmodified bamboo powder lacks -CF bonds, thus failing to form a "hydrophobic barrier," significantly weakening its hydrophobic ability; self-healing slowed down because the bonding force between unmodified bamboo powder and polyurea resin was weak (without KH-550). The chemical bonding of the coupling agent prevents the formation of a "physical bridge" at the cracks; weather resistance decreases: bamboo powder, without fluorine modification, is prone to moisture absorption and aging when exposed to the environment for a long time, leading to slight cracking of the coating; Comparative Example 2 (without sulfone chain extender): molecular density and self-healing synergy decrease, hydrophobicity slightly decreases: sulfone chain extender can form "sulfone crosslinking points" with polyurea resin molecular chains, enhancing molecular chain density and blocking water molecule penetration; after its absence, the molecular gap increases, and the water contact angle decreases; self-healing efficiency decreases: sulfone groups and disulfide bonds have a synergistic effect, and the strong polarity of sulfone groups can assist in the rapid positioning and regeneration of disulfide bonds after breakage; after its absence, the regeneration efficiency of disulfide bonds decreases; weather resistance decreases: insufficient molecular density allows oxygen and ultraviolet rays in the environment to easily penetrate into the coating, leading to slight cracking. Comparative Example 3 (without disulfide di(p-amino)benzene): self-healing ability significantly decreases: disulfide di(p-amino)benzene Benzene is the sole source of disulfide bonds in polyurea resin, and the "dynamic reversibility" of disulfide bonds is the core of self-repair (disulfide bonds can recombine after breaking at the crack); when missing, repair relies solely on hydrogen bonds, resulting in a significant decrease in efficiency; hydrophobicity decreases slightly: disulfide bonds can enhance the crosslinking density of molecular chains, thus helping to improve the hydrophobic effect; when missing, the intermolecular gaps increase slightly, and the water contact angle decreases; weather resistance decreases: insufficient crosslinking density weakens the coating's resistance to environmental aging, leading to slight cracking.

[0031] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0032] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0033] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments.

Claims

1. A polyurea waterproof coating, characterized in that, It includes the following components by weight: 40-50 parts by weight of polyurea resin, 3-5 parts by weight of fluorine-modified bamboo powder, 0.2-0.4 parts by weight of BYK-071 defoamer, and 0.1-0.3 parts by weight of BYK-345 leveling agent; The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: React bamboo powder with KH-550 to obtain coupling agent modified bamboo powder; Step 2: The coupling agent-modified bamboo powder and perfluorooctanoyl chloride are reacted under the action of triethylamine catalyst to obtain fluorine-modified bamboo powder.

2. The polyurea waterproof coating according to claim 1, characterized in that, The preparation method of the polyurea resin is as follows: S1. Under a nitrogen atmosphere, N,N,N'-trimethylethylenediamine and 4,4'-difluorodiphenyl sulfone were added to N-methylpyrrolidone solvent, anhydrous potassium carbonate was added as a catalyst, and the reaction was carried out at 160-170℃ for 4-5 h. After the reaction, the mixture was filtered and dried to obtain intermediate 1. S2. Add intermediate 1 and 2-chloroethanol to N,N-dimethylformamide solvent, stir and mix, react at 65-70℃ for 2-4 hours, after which rotary distillation and filtration are performed to obtain sulfone chain extender. S3. Add 2-3 mmol of polytetrahydrofuran ether glycol, 2-4 g of polypropylene glycol, and N,N-dimethylformamide solvent to a reaction flask, dehydrate at 115-120℃ for 1.5-2 h, cool to 50-55℃, and continue to add 4-6.5 mmol of isophorone diisocyanate and 0.1-0.12 mmol of dibutyltin dilaurate. Heat to 85-90℃ and react for 2-3 h, cool to 50-60℃, and then continue to add 0.5-0.7 mmol of dithiobis(p-amino)benzene and 0.5-0.6 mmol of sulfone chain extender. React for 40-50 min, and after completion, polyurea resin is obtained.

3. The polyurea waterproof coating according to claim 2, characterized in that, In S1, the ratio of N,N,N'-trimethylethylenediamine, 4,4'-difluorodiphenyl sulfone, and anhydrous potassium carbonate is 2-4 mmol: 1-2 mmol: 0.1-0.2 mmol.

4. The polyurea waterproof coating according to claim 2, characterized in that, In S2, the molar ratio of intermediate 1 to 2-chloroethanol is 1.2-1.6 mmol: 4.8-6.5 mmol.

5. The polyurea waterproof coating according to claim 2, characterized in that, In S3, the molecular weights of polytetrahydrofuran ether diol and polypropylene glycol are 2000.

6. The polyurea waterproof coating according to claim 1, characterized in that, The preparation method of the fluorine-modified bamboo powder is as follows: Step 1: Add 2-3g of bamboo powder to a reaction flask containing 0.1-0.15g of KH-550, heat to 160-180℃ and react for 1-2 hours, then let stand for 40-48 hours. After the reaction is complete, filter, dry, disperse in acetone, stir, filter and wash again to obtain coupling agent modified bamboo powder. Step 2: Add the coupling agent-modified bamboo powder and perfluorooctanoic acid chloride to N,N-dimethylformamide solvent, stir and mix, add triethylamine catalyst, react at 25-35℃ for 2-3 hours, after which vacuum distillation, washing, and drying are carried out to obtain fluorine-modified bamboo powder.

7. The polyurea waterproof coating according to claim 6, characterized in that, In step two, the ratio of the coupling agent-modified bamboo powder, perfluorooctanoyl chloride, and triethylamine is 1.4-2 mmol: 0.64-0.9 g: 0.01-0.02 g.

8. A method for preparing a polyurea waterproof coating as described in any one of claims 1-7, characterized in that, The preparation method of the polyurea waterproof coating is as follows: add polyurea resin, fluorine-modified bamboo powder, BYK-071 defoamer, and BYK-345 leveling agent into a stirrer and stir for 20-30 minutes to obtain the polyurea waterproof coating.

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