Preparation process of water-based epoxy resin anticorrosive wear-resistant marking paint

Abstract

This invention relates to the field of coating technology and discloses a preparation process for a waterborne epoxy resin anti-corrosion and wear-resistant road marking coating. The invention involves adding water, 1.5-6 parts by weight of hyperbranched sulfonated polyurethane, 10-30 parts by weight of silicon carbide micropowder, and 100 parts by weight of waterborne epoxy resin to a grinding mill, followed by grinding and dispersion to obtain the waterborne epoxy resin anti-corrosion and wear-resistant road marking coating. The side chains of the hyperbranched polyurethane contain sulfonate anchoring groups, and the main molecular chain contains polyethylene glycol solvation chains, which can act as dispersants to improve the dispersibility of silicon carbide micropowder in the waterborne epoxy resin coating, significantly improving the wear resistance and salt spray corrosion resistance of the coating film. The hyperbranched sulfonated polyurethane contains unique three-dimensional hyperbranched molecular chains, which form physical chain entanglement with the epoxy resin molecular chains, playing a certain toughening role and improving the toughness and flexural strength of the epoxy resin.

Description

Technical Field

[0001] This invention relates to the field of coating technology, specifically to a preparation process for a water-based epoxy resin anti-corrosion and wear-resistant marking coating. Background Technology

[0002] Epoxy resin coatings possess excellent waterproof, insulating, and mechanical strength properties, making them widely used in railway bridges, vehicles and ships, oil extraction equipment, and concrete flooring. However, epoxy resin coatings suffer from poor cured film toughness, low flexural strength, and poor abrasion resistance. They are prone to cracking and damage when subjected to impact or external forces, limiting their practical application in outdoor transportation, road markings, and other applications.

[0003] Silicon carbide possesses high mechanical strength, excellent wear resistance, and strong thermal conductivity, making it important in polymer materials. However, silicon carbide micropowder is prone to agglomeration and exhibits poor compatibility with epoxy resins. Therefore, surface modification of silicon carbide using dispersants and silane coupling agents is necessary. Polyurethane is a polymer with high mechanical strength, high toughness, and excellent elasticity. It can be widely used as a toughening agent, dispersant, and curing agent in materials such as epoxy resins. Chinese patent application CN116178734A discloses a hydroxyl-terminated hyperbranched polyurethane-modified epoxy resin and its preparation method. The prepared epoxy resin exhibits good toughness, mechanical strength, and high-temperature resistance. However, this patent application does not address the issue of poor wear resistance in epoxy resins. Summary of the Invention

[0004] (i) The technical problem solved by this invention is that it solves the problem of poor wear resistance of epoxy resin coatings, and at the same time improves the anti-corrosion performance of epoxy resin coatings.

[0005] (II) The technical solution of the present invention is: a preparation process of a water-based epoxy resin anti-corrosion and wear-resistant marking coating:

[0006] S1. Nitrogen gas is introduced into the reaction vessel, and dry polyethylene glycol, isocyanate monomer, and dibutyltin dilaurate are added. The mixture is heated to 70-75℃ and reacted for 2.5-3 hours. Then, sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate is added, and the reaction is continued for 40-60 minutes. The mixture is then cooled and discharged to obtain hyperbranched sulfonated polyurethane.

[0007] S2. Add water, 1.5-6 parts by weight of hyperbranched sulfonated polyurethane, and 10-30 parts by weight of silicon carbide micro powder to the grinding mill, grind and disperse, then add 100 parts by weight of waterborne epoxy resin, 0.4-0.8 parts by weight of defoamer, and 0.2-0.5 parts by weight of wetting agent, grind and disperse, and finally add 36-40 parts by weight of curing agent to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

[0008] Preferably, in (1), the molar ratio of polyethylene glycol, isocyanate monomer, dibutyltin dilaurate, and sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate is 1:(2.5-2.6):(0.04-0.06):(0.66-0.72).

[0009] Preferably, the isocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

[0010] Preferably, the preparation process of sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate is as follows: 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 3-chloro-1,2-propanediol, and sodium hydroxide are added to water, and the reaction is carried out at 20-35°C for 12-18 hours. The mixture is then extracted with ethyl acetate, and the organic phase is distilled under reduced pressure. The product is recrystallized in a 40% (v / v) aqueous ethanol solution to obtain sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate.

[0011] Preferably, the molar ratio of 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 3-chloro-1,2-propanediol, and sodium hydroxide is 1:(1-1.2):(2-2.2).

[0012] (III) Technical effects of the present invention: Sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate containing three hydroxyl groups is used as a branched monomer to polymerize with polyethylene glycol and isocyanate monomers to obtain hyperbranched sulfonated polyurethane, which is then blended with silicon carbide micro powder, waterborne epoxy resin, etc. to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

[0013] The hyperbranched polyurethane of this invention contains sulfonate anchoring groups in its side chains, which have strong interaction forces with the silicon carbide surface. At the same time, the main molecular chain contains polyethylene glycol solvation chains, which allows the hyperbranched sulfonated polyurethane to act as a dispersant, improving the dispersibility of silicon carbide micropowder in waterborne epoxy resin coatings. The silicon carbide micropowder is uniformly dispersed in the coating matrix, which significantly improves the wear resistance of the coating film, reduces frictional mass loss, and the uniformly dispersed silicon carbide micropowder can inhibit the entry of corrosive media into the epoxy resin matrix, thereby improving the salt spray corrosion resistance of the coating film.

[0014] The hyperbranched sulfonated polyurethane of this invention improves the interfacial compatibility between silicon carbide and epoxy resin, which is beneficial for improving the mechanical properties of the coating film, such as pencil hardness and flexural strength. Simultaneously, the polyurethane contains unique three-dimensional hyperbranched molecular chains, which form physical chain entanglement with the epoxy resin molecular chains, playing a certain toughening role and improving the toughness and flexural strength of the epoxy resin. The prepared epoxy resin coating has excellent practical applications in outdoor traffic, road marking, and other fields. Detailed Implementation

[0015] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0016] The following waterborne epoxy resin, model EM 1006, was purchased from Nanjing Qinghai Trading Co., Ltd. The curing agent, model Epikure 8545-W-52 waterborne amine curing agent, was purchased from Guangzhou Linsheng Chemical Co., Ltd. The silicon carbide micropowder, with an average particle size of 1.5 μm, was purchased from Qinghe County Xingxin New Material Technology Co., Ltd.

[0017] 2-[(2-hydroxyethyl)amino]ethanesulfonic acid was prepared according to the method described in the journal *Monatsh Chem*, 139, 799-803 (2008), in the paper "The Knoevenagel reaction in water catalyzed by zwitterionic liquids" (DOI: 10.1007 / s00706-008-0855-y).

[0018] Add 0.1 mol of ethanolamine (structural formula: [structural formula not provided]) to 20 mL of dichloromethane. 0.1 mol 1,3-propanesulfonate lactone (structural formula: The reaction was carried out at room temperature for 1 hour, followed by vacuum distillation. The mixture was washed with a mixed solution of chloroform, petroleum ether, and ethanol, and dried to obtain 2-[(2-hydroxyethyl)amino]ethanesulfonic acid. The structural formula is... .

[0019] Example 1:

[0020] (1) Add 50 mmol of 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 60 mmol of 3-chloro-1,2-propanediol and 100 mmol of sodium hydroxide to 140 mL of water, react at 20 °C for 18 h, extract with ethyl acetate, distill the organic phase under reduced pressure, and recrystallize the product in a 40% ethanol aqueous solution to obtain sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate.

[0021] (2) Nitrogen gas was introduced into the reaction vessel, and 100 mmol of dry polyethylene glycol, 250 mmol of isophorone diisocyanate and 4 mmol of dibutyltin dilaurate were added. The mixture was heated to 75°C and reacted for 2.5 h. Then 66.7 mmol of sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate was added and the reaction was continued for 40 min. The mixture was cooled and discharged to obtain hyperbranched sulfonated polyurethane.

[0022] (3) Add 1.3L of water, 15g of hyperbranched sulfonated polyurethane, and 100g of silicon carbide micro powder to the grinder, grind and disperse, then add 1kg of waterborne epoxy resin, 7g of defoamer (model FoamStar ED 2522), and 2g of wetting agent (model TEGO500), grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

[0023] Example 2:

[0024] (1) Add 50 mmol of 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 50 mmol of 3-chloro-1,2-propanediol and 110 mmol of sodium hydroxide to 120 mL of water, react at 35 °C for 12 h, extract with ethyl acetate, distill the organic phase under reduced pressure, and recrystallize the product in a 40% ethanol aqueous solution to obtain sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate.

[0025] (2) Nitrogen gas was introduced into the reaction vessel, and 100 mmol of dry polyethylene glycol, 260 mmol of toluene-2,4-diisocyanate and 6 mmol of dibutyltin dilaurate were added. The mixture was heated to 70°C and reacted for 3 h. Then 72 mmol of sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate was added and the reaction was continued for 60 min. The mixture was cooled and discharged to obtain hyperbranched sulfonated polyurethane.

[0026] (3) Add 1.6L of water, 35g of hyperbranched sulfonated polyurethane, and 200g of silicon carbide micro powder to the grinder, grind and disperse, then add 1kg of waterborne epoxy resin, 8g of defoamer (model FoamStar ED 2522), and 3g of wetting agent (model TEGO500), grind and disperse, and finally add 360g of curing agent to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

[0027] Example 3:

[0028] (1) Nitrogen gas was introduced into the reaction vessel, and 100 mmol of dry polyethylene glycol, 250 mmol of isophorone diisocyanate and 6 mmol of dibutyltin dilaurate were added. The mixture was heated to 75°C and reacted for 3 h. Then 70 mmol of sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate (prepared from Example 1) was added, and the reaction was continued for 60 min. The mixture was cooled and discharged to obtain hyperbranched sulfonated polyurethane.

[0029] (2) Add 1.6L of water, 60g of hyperbranched sulfonated polyurethane, and 300g of silicon carbide micro powder to the grinder and grind and disperse. Then add 1kg of waterborne epoxy resin, 4g of defoamer (model FoamStar ED 2522), and 5g of wetting agent (model TEGO500) and grind and disperse. Finally, add 372g of curing agent to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

[0030] Comparative Example 1:

[0031] (1) Add 1.3L of water, 1kg of waterborne epoxy resin, 7g of defoamer (FoamStar ED2522), and 2g of wetting agent (TEGO500) to the grinder, grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin marking paint.

[0032] Comparative Example 2:

[0033] (1) Add 1.3L of water, 15g of hyperbranched sulfonated polyurethane, 1kg of waterborne epoxy resin, 7g of defoamer (model FoamStar ED 2522), and 2g of wetting agent (model TEGO500) to the grinder, grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin marking paint.

[0034] Comparative Example 3:

[0035] (1) Add 1.3L of water, 100g of silicon carbide micro powder, 1kg of waterborne epoxy resin, 7g of defoamer (model FoamStar ED 2522), and 2g of wetting agent (model TEGO500) to the grinder, grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin marking paint.

[0036] Comparative Example 4:

[0037] (1) Nitrogen gas was introduced into the reaction vessel, and 100 mmol of dry polyethylene glycol, 250 mmol of isophorone diisocyanate and 4 mmol of dibutyltin dilaurate were added. The mixture was heated to 75°C and reacted for 2.5 h. Then 66.7 mmol of trimethylolpropane was added and the reaction was continued for 40 min. The mixture was cooled and discharged to obtain hyperbranched polyurethane.

[0038] (2) Add 1.3L of water, 15g of hyperbranched polyurethane and 100g of silicon carbide micro powder to the grinder, grind and disperse, then add 1kg of waterborne epoxy resin, 7g of defoamer (model FoamStar ED 2522) and 2g of wetting agent (model TEGO500), grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin marking paint.

[0039] Comparative Example 5:

[0040] (1) Nitrogen gas was introduced into the reaction vessel, and 100 mmol of dry polyethylene glycol, 250 mmol of isophorone diisocyanate, and 4 mmol of dibutyltin dilaurate were added. The mixture was heated to 75°C and reacted for 2.5 h. Then 100 mmol of sodium 1,2-dihydroxy-3-propanesulfonate was added. Continue the reaction for 40 minutes, cool and discharge to obtain sulfonated polyurethane.

[0041] (2) Add 1.3L of water, 15g of sulfonated polyurethane and 100g of silicon carbide micro powder to the grinder, grind and disperse, then add 1kg of waterborne epoxy resin, 7g of defoamer (model FoamStar ED 2522) and 2g of wetting agent (model TEGO500), grind and disperse, and finally add 400g of curing agent to obtain waterborne epoxy resin marking paint.

[0042] The coating was sprayed onto the tinplate surface and cured sequentially at 90℃ for 2 hours and 120℃ for 3 hours. Salt spray resistance was tested according to the method specified in GB / T 1771-2007. Friction loss and abrasion resistance were tested according to the method specified in GB / T 1768-2006. Pencil hardness was tested according to the method specified in GB / T 6739-2022.

[0043] The coating is poured into a mold and cured to form a film sample. The flexural strength is tested according to the method specified in GB / T 9314-2008.

[0044] Table 1 Coating Performance Tests Salt spray resistance (2000h) Frictional mass loss (mg) Pencil hardness Bending strength (MPa) Example 1 No bubbles, no rust 54.7 5H 109.8 Example 2 No bubbles, no rust 38.6 6H 125.3 Example 3 No bubbles, no rust 31.2 6H 105.9 Comparative Example 1 Bubbling, rusting 74.8 3H 94.6 Comparative Example 2 Bubbling, rusting 74.1 3H 103.3 Comparative Example 3 It bubbles and does not rust. 61.3 4H 88.4 Comparative Example 4 It bubbles and does not rust. 60.9 4H 96.7 Comparative Example 5 No bubbles, no rust 55.6 5H 101.0

[0045] Tests showed that the epoxy resin coating in Comparative Example 1 had poor salt spray resistance, poor corrosion resistance, high frictional mass loss, poor wear resistance, low pencil hardness and flexural strength, and poor mechanical properties.

[0046] Example 1 incorporated hyperbranched sulfonated polyurethane and silicon carbide micropowder. The polyurethane side chains contain sulfonate anchoring groups, exhibiting strong interaction with the silicon carbide surface. Simultaneously, the main molecular chain contains polyethylene glycol solvation chains, allowing the hyperbranched sulfonated polyurethane to act as a dispersant, improving the dispersibility of silicon carbide micropowder in waterborne epoxy resin coatings. The uniform dispersion of silicon carbide micropowder within the coating matrix significantly enhances the wear resistance of the coating film, reduces frictional mass loss, and inhibits the ingress of corrosive media into the epoxy resin matrix, thereby improving the salt spray resistance of the coating film. Furthermore, the hyperbranched sulfonated polyurethane improves the interfacial compatibility between silicon carbide and epoxy resin, which is beneficial for improving the pencil hardness, flexural strength, and other mechanical properties of the coating film. This sulfonated polyurethane contains unique three-dimensional hyperbranched molecular chains, forming physical chain entanglement with the epoxy resin molecular chains, thus providing a certain toughening effect and improving the toughness and flexural strength of the epoxy resin.

[0047] Compared with Example 1, Comparative Example 2 only added hyperbranched sulfonated polyurethane and did not add silicon carbide micro powder. The coating film had poor salt spray resistance, corrosion resistance and wear resistance, and lower pencil hardness, but increased bending strength and better toughness.

[0048] Comparative Example 3 only added silicon carbide micro powder, which had poor dispersibility in epoxy resin, poor salt spray corrosion resistance of the paint film, and large frictional mass loss, resulting in poor wear resistance. At the same time, the poor compatibility between silicon carbide micro powder and epoxy resin had an adverse effect on its flexural strength, leading to a decrease in flexural strength.

[0049] Comparative Example 4 uses conventional trimethylolpropane as a raw material to prepare hyperbranched polyurethane that does not contain sodium sulfonate anchoring groups. The interaction force with the silicon carbide surface is weak, making it difficult to improve the dispersibility of silicon carbide micropowder in waterborne epoxy resin coatings. This results in poor salt spray corrosion resistance and wear resistance of the coating film, as well as low hardness and flexural strength.

[0050] Comparative Example 5 uses conventional sodium 1,2-dihydroxy-3-propanesulfonate as a raw material to prepare polyurethane with linear molecular chains that do not contain three-dimensional hyperbranched molecular chains. The toughening effect is poor, and the toughness and flexural strength of the epoxy resin are low.

Claims

1. A preparation process for a water-based epoxy resin anti-corrosion and wear-resistant marking paint, characterized in that, The preparation process is as follows: S1. Nitrogen gas is introduced into the reaction vessel, and dry polyethylene glycol, isocyanate monomer, and dibutyltin dilaurate are added. The mixture is heated to the reaction temperature and the reaction is carried out. Then, sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate is added, the reaction is continued, and the mixture is cooled and discharged to obtain hyperbranched sulfonated polyurethane. S2. Add water, 1.5-6 parts by weight of hyperbranched sulfonated polyurethane, and 10-30 parts by weight of silicon carbide micro powder to the grinding mill, grind and disperse, then add 100 parts by weight of waterborne epoxy resin, 0.4-0.8 parts by weight of defoamer, and 0.2-0.5 parts by weight of wetting agent, grind and disperse, and finally add 36-40 parts by weight of curing agent to obtain waterborne epoxy resin anti-corrosion and wear-resistant marking paint.

2. The preparation process of the water-based epoxy resin anti-corrosion and wear-resistant marking paint according to claim 1, characterized in that, The reaction temperature in (1) is 70-75℃; the reaction time for the first reaction is 2.5-3h, and the reaction time for the second reaction is 40-60min.

3. The preparation process of the water-based epoxy resin anti-corrosion and wear-resistant marking paint according to claim 1, characterized in that, The molar ratio of polyethylene glycol, isocyanate monomer, dibutyltin dilaurate, and sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate in (1) is 1:(2.5-2.6):(0.04-0.06):(0.66-0.72).

4. The preparation process of the water-based epoxy resin anti-corrosion and wear-resistant marking paint according to claim 3, characterized in that, The isocyanate monomer is isophorone diisocyanate or toluene-2,4-diisocyanate.

5. The preparation process of the waterborne epoxy resin anti-corrosion and wear-resistant marking paint according to claim 3, characterized in that, The preparation process of sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate is as follows: 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 3-chloro-1,2-propanediol, and sodium hydroxide are added to water. After the reaction, the mixture is extracted with ethyl acetate, the organic phase is distilled under reduced pressure, and the product is recrystallized in an aqueous ethanol solution to obtain sodium 2-[(2,3-dihydroxypropyl)(2-hydroxyethyl)amino]ethanesulfonate.

6. The preparation process of the water-based epoxy resin anti-corrosion and wear-resistant marking paint according to claim 5, characterized in that, The molar ratio of 2-[(2-hydroxyethyl)amino]ethanesulfonic acid, 3-chloro-1,2-propanediol, and sodium hydroxide is 1:(1-1.2):(2-2.2).

7. The preparation process of the water-based epoxy resin anti-corrosion and wear-resistant marking paint according to claim 5, characterized in that, The reaction temperature is 20-35℃, and the reaction time is 12-18h.