A silicone-modified acrylic resin coating, and a method of preparing and using the same

Abstract

This invention discloses an organosilicon-modified acrylic resin coating, its preparation method, and its application, belonging to the field of surface protection technology. The organosilicon-modified acrylic resin coating of this invention comprises the following raw materials in parts by weight: 92-99 parts of organosilicon-modified acrylic resin and 1-8 parts of modified SiO2@FGO nano-hybrids. This invention achieves surface modification of graphene oxide using a silane coupling agent, and further obtains the coating through in-situ hydrolysis deposition and modification of SiO2 nanoparticles. The organosilicon-modified acrylic resin coating with composite nanofiller exhibits excellent resistance to chloride ion corrosion, carbonization, alkali resistance, weather resistance, and adhesion, and can be used for surface protection of marine reinforced concrete engineering projects.

Description

Technical Field

[0001] This invention belongs to the field of surface protection technology, specifically relating to an organosilicon-modified acrylic resin coating, its preparation method, and its application. Background Technology

[0002] Marine reinforced concrete engineering projects are subjected to the individual or combined effects of chloride, carbonation, sulfate, freeze-thaw cycles, and alkali-aggregate corrosion. This harsh corrosive environment exacerbates the damage to reinforced concrete structures and shortens their service life. Among these factors, chloride corrosion leading to steel reinforcement corrosion and ultimately concrete structure failure is considered the primary cause of damage to marine engineering projects. Chloride ions have extremely strong penetrating power; once the free chloride ion content in the solution around the steel reinforcement reaches a certain level, it will cause localized damage to the protective film on the steel reinforcement surface, forming small anodes that allow iron to dissolve rapidly and form Fe. 2+ Cl - And with Fe 2+ The rapid combination to form FeCl2 accelerates the anodic reaction; and after leaving the steel reinforcement surface, FeCl2 quickly reacts with OH- in the surrounding solution. - It reacts with O2 to convert into Fe(OH)2 or Fe3O4, while producing the byproduct H. + Throughout the process, Cl - Instead of being consumed, it generated a large amount of H. + This lowers the pH value of the solution surrounding the reinforcing steel, leading to more rapid corrosion of the steel.

[0003] Among numerous anti-corrosion strategies, surface coating is one of the most widely used technical means in concrete protection systems, and organic coatings are currently one of the most commonly used protective materials in marine reinforced concrete engineering. The mainstream coating systems currently include epoxy resin, polyurethane, acrylic resin, and their composite systems. Among these, acrylic resin stands out due to its advantages such as environmental friendliness, excellent weather resistance, good chemical corrosion resistance, and adhesion. However, when facing the multi-factor coupled corrosion environment of the ocean, these traditional coatings all reveal significant shortcomings: epoxy resin coatings are prone to chalking and have poor weather resistance; polyurethane is expensive and sensitive to construction humidity; and acrylic resin, due to its high molecular chain flexibility and high free volume, is susceptible to water molecules and chloride ions. - There is still room for improvement in its barrier properties, and in the high-alkali environment of concrete, ester bonds are prone to saponification, which leads to debonding of the coating-substrate interface and rapid loss of protective function.

[0004] Organosilicones are widely used to modify acrylic resins due to their unique Si-O-Si backbone (bond energy 452 kJ / mol, far higher than the 347 kJ / mol of C-C bonds) and low surface energy. Introducing organosilicon monomers through copolymerization or hybridization can construct inorganic-organic hybrid structures within the polymer network, significantly improving the coating's thermal stability, hydrophobicity, and interfacial compatibility with inorganic substrates. However, current reports on organosilicon-modified acrylic resin coatings mainly focus on coatings without or with only nanofillers. For organosilicon-modified acrylic resin coatings with multiple nanofillers, which promise higher performance, the compatibility between the filler and the resin matrix, especially the agglomeration problem of the nanofiller, remains to be solved. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide an organosilicon-modified acrylic resin coating, its preparation method and application. The organosilicon-modified acrylic resin coating with nanofiller described in this invention has good resistance to chloride ion erosion, carbonation resistance, alkali resistance, weather resistance and adhesion, and can be used for surface protection of marine reinforced concrete engineering.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides an organosilicon-modified acrylic resin coating, characterized in that it comprises the following raw materials in parts by weight: 92-99 parts of silicone-modified acrylic resin and 1-8 parts of modified SiO2@FGO nano-hybrid.

[0007] Preferably, the preparation method of the modified SiO2@FGO nanohybrid is as follows: S1. Graphene oxide is dispersed in deionized water and ultrasonically treated to obtain a graphene oxide dispersion; then a silane coupling agent hydrolysate is added and heated to react; after the reaction is completed, modified graphene oxide is obtained through post-treatment. S2. Modified graphene oxide was dispersed in an aqueous ethanol solution and the pH was adjusted. Then, a mixed solution of tetraethoxysilane and silane coupling agent was added dropwise while stirring the reaction. After the reaction was completed, SiO2@FGO nano-hybrids were obtained through post-treatment. S3. Add SiO2@FGO nanohybrids to a silane coupling agent solution and heat to react; after the reaction is completed, post-treatment is performed to obtain modified SiO2@FGO nanohybrids.

[0008] Preferably, the concentration of the graphene oxide dispersion in S1 is 0.05–2.0 mg / mL.

[0009] Preferably, the mass ratio of silane coupling agent to graphene oxide in S1 is (0.2-8):1.

[0010] Furthermore, the pH value of the hydrolysate of the silane coupling agent in S1 is 3.5 to 5.5.

[0011] Furthermore, the heating reaction in S1 is carried out at a temperature of 50–85°C for 3–24 hours.

[0012] Preferably, the mass ratio of the mixed solution to the modified graphene oxide in S2 is (0.1-3):1.

[0013] Preferably, the mixed solution in S2 is prepared by mixing tetraethoxysilane and a silane coupling agent in a molar ratio of (0.5-5):1.

[0014] Furthermore, in the S2 ethanol-water solution, the volume ratio of ethanol to water is (2-6):1.

[0015] Preferably, in step S2, the pH is adjusted to 8-11; the pH is adjusted using 1-28 wt.% ammonia, 0.1-1 mol / L sodium hydroxide solution, or 5-25 wt.% tetramethylammonium hydroxide solution.

[0016] Furthermore, the stirring reaction temperature in S2 is 15–50°C, and the stirring reaction time is 6–48 hours.

[0017] Preferably, the mass ratio of SiO2@FGO nano-hybrid to silane coupling agent in S3 is (0.5~5):1; and the concentration of silane coupling agent solution is 0.5~15 wt.%.

[0018] Furthermore, the solvent of the silane coupling agent solution in S3 is obtained by mixing ethanol and water in a volume ratio of (1-4):1.

[0019] Furthermore, the heating reaction temperature in S3 is 40–80°C; the heating reaction time is 1–12 hours.

[0020] Furthermore, the preparation method of the organosilicon-modified acrylic resin is as follows: In an inert gas atmosphere, acrylate monomers and silane coupling agents are dissolved in an organic solvent, heated, and then an initiator solution is added dropwise to carry out a copolymerization reaction. After the addition is complete, the reaction is continued at the temperature to obtain an organosilicon-modified acrylic resin solution.

[0021] Furthermore, the mass ratio of the acrylate monomer mixture to the silane coupling agent is (80-98):(2-20).

[0022] Further, the acrylate monomer includes at least one of a hard monomer, a soft monomer, and a functional monomer; the hard monomer is at least one of methyl methacrylate and styrene; the soft monomer is at least one of ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate; and the functional monomer is at least one of hydroxyethyl acrylate, hydroxypropyl acrylate, and acrylic acid. Furthermore, the amount of initiator used is 0.2% to 3.0% of the total mass of the acrylate monomer and the silane coupling agent B; The concentration of the initiator solution is 1-10 wt.%; the initiator is selected from at least one of azobisisobutyronitrile, benzoyl peroxide, potassium persulfate, or ammonium persulfate.

[0023] Furthermore, the initial solid content of the copolymerization system is 30-70%; The copolymerization reaction temperature is 65–90°C; The initiator solution is added over a period of 1 to 5 hours. The heat preservation reaction time is 2 to 8 hours.

[0024] This invention also provides a method for preparing the above-mentioned organosilicon-modified acrylic resin coating, comprising the following steps: Weigh the raw materials according to their weight. Organosilicon-modified acrylic resin was dissolved in a solvent and mixed with modified SiO2@FGO nano-hybrids. The mixture was then mechanically stirred and ultrasonically dispersed to obtain an organosilicon-modified acrylic resin coating.

[0025] The mechanical stirring speed is 200-2000 rpm, and the mechanical stirring time is 0.25-3 hours; the ultrasonic dispersion time is 5-90 minutes.

[0026] This invention also provides the application of the above-mentioned organosilicon-modified acrylic resin coating in the surface protection of marine reinforced concrete engineering.

[0027] It contains at least the following beneficial technical effects: 1. Addressing the critical technical challenge of saponification and degradation of acrylic resin coatings in highly alkaline environments such as concrete, this invention addresses this issue by designing the molecular structure of the resin matrix. A silane coupling agent is used to copolymerize with acrylate monomers, introducing stable Si-O-Si bonds into the polymer molecular chain. This structure partially replaces the easily hydrolyzed ester bonds in traditional acrylic resins, significantly improving the chemical stability of the resin matrix to strongly alkaline media and fundamentally enhancing the durability of the coating in harsh alkaline environments. Simultaneously, the introduced organosilicon segments effectively improve the resin's hydrophobicity and thermal stability, providing a foundation for superior corrosion resistance and weather resistance in the coating.

[0028] 2. This invention designs and prepares a modified SiO2@FGO nanohybrid with a special structure as a key functional filler. This filler is obtained by surface modification of graphene oxide using a silane coupling agent, followed by in-situ hydrolysis deposition and further modification of SiO2 nanoparticles. This structure integrates multiple functions: First, the silane coupling agent modification and in-situ hydrolysis deposition method significantly improve the compatibility and interfacial bonding between the filler and the organosilicon-modified resin matrix, promoting uniform dispersion at the nanoscale; second, the dot-like support formed by SiO2 nanoparticles on the modified graphene oxide sheets effectively prevents face-to-face stacking of the sheets, overcoming the agglomeration problem of the nanofiller; third, this hybrid structure constructs a denser and more tortuous physical barrier within the coating, allowing SiO2 particles to fill the channels between the modified graphene oxide sheets, further extending and blocking the penetration path of corrosive media based on the "maze effect."

[0029] 3. Based on the above-mentioned resin matrix modification design and nanofiller structural innovation, the coating prepared by this invention exhibits synergistically enhanced comprehensive performance after film formation. The coating combines the chemical inertness and heat resistance of organosilicon with the weather resistance and film-forming properties of acrylic resin. Furthermore, thanks to the uniform dispersion and composite barrier effect of the hybrid nanofillers, its corrosion resistance, mechanical strength, and long-term stability are significantly improved. This coating is particularly suitable for surface protection of marine reinforced concrete engineering projects, effectively resisting the erosion of various corrosive media and achieving long-term protection. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Every smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be obvious to those skilled in the art. This application specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] Unless otherwise specified, "room temperature" and "normal temperature" in this invention refer to 25±2℃.

[0036] Unless otherwise specified, all raw materials or instruments used in the following embodiments of the present invention are commercially available.

[0037] Example 1 This embodiment provides a method for preparing an organosilicon-modified acrylic resin coating with multiple nanofillers, the specific steps of which are as follows: S1. Weigh 0.5 g of graphene oxide and disperse it in 1000 mL of deionized water. Sonicate the solution for 1 hour to obtain a dispersion with a concentration of 0.5 mg / mL. Add 1.0 g of silane coupling agent KH-550 to a mixed solvent consisting of 80 mL of ethanol and 20 mL of deionized water. Adjust the pH to 4.5 with glacial acetic acid and stir for 30 minutes to obtain a hydrolysate. Add the hydrolysate to the graphene oxide dispersion and react with mechanical stirring at 70°C for 8 hours. After the reaction, centrifuge the mixture at 10000 rpm for 15 minutes, discard the supernatant, and wash the precipitate three times each with deionized water and ethanol. Then, dry the precipitate in a vacuum drying oven at 60°C for 36 hours. Grind the precipitate to obtain silane coupling agent modified graphene oxide powder.

[0038] Under nitrogen protection, 25 g of methyl methacrylate, 20 g of butyl acrylate, 5 g of hydroxyethyl acrylate, 5 g of silane coupling agent KH-570, and 50 g of ethyl acetate were added to a three-necked flask equipped with a condenser, stirrer, and thermometer. The mixture was stirred to dissolve and heated to 80°C. 0.5 g of azobisisobutyronitrile (AIBN) initiator was dissolved in 10 g of ethyl acetate to prepare an initiator solution with a mass concentration of 4.8%. This initiator solution was added dropwise to the reaction flask at a uniform rate over 3 hours. After the addition was complete, the reaction was maintained at 80°C for another 5 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a silicone-modified acrylic resin solution with a solid content of 50%.

[0039] S2. 0.5 g of modified graphene oxide powder was dispersed in a mixed solvent consisting of 160 mL of ethanol and 40 mL of deionized water, and ultrasonically dispersed for 30 minutes. Ammonia solution with a mass concentration of 25% was added dropwise to the dispersion to adjust the pH of the system to 10.0. 2.08 g of tetraethoxysilane and 1.18 g of silane coupling agent KH-560 (molar ratio 2:1) were mixed and slowly added dropwise to the above dispersion under stirring. The reaction was carried out with continuous stirring at 30°C for 24 hours. After the reaction was completed, the product was centrifuged at 10,000 rpm for 15 minutes. The precipitate was washed three times with ethanol and dried under vacuum at 60°C for 24 hours to obtain SiO2@FGO nano-hybrid powder.

[0040] S3. Add 1.0 g of SiO2@FGO nano-hybrid powder to a mixed solution consisting of 2.0 g of silane coupling agent KH-550, 38 g of ethanol, and 10 g of deionized water (ethanol to water volume ratio approximately 2:1). Stir the mixture at 65°C for 6 hours. After the reaction is complete, centrifuge the mixture, wash it three times with ethanol, and dry it under vacuum at 60°C for 24 hours to obtain the modified SiO2@FGO nano-hybrid powder.

[0041] S4. Weigh 80 g of silicone-modified acrylic resin solution (containing 40 g of solid resin). Weigh 0.4 g of modified SiO2@FGO nano-hybrid powder. Mix the nanofiller with part of the resin solution, first mechanically stir at 1200 rpm for 1.5 hours, then ultrasonically disperse for 30 minutes. Then combine this dispersion with the remaining resin solution and stir at low speed until homogeneous to obtain a silicone-modified acrylic resin coating with nanofiller.

[0042] Example 2 The only difference between this embodiment and Embodiment 1 is that the amount of silane coupling agent KH-550 used in step S1 is 0.125 grams, that is, the mass ratio of silane coupling agent to graphene oxide is 0.25:1.

[0043] Example 3 The only difference between this embodiment and Embodiment 1 is that the amount of silane coupling agent KH-550 used in step S1 is 2.0 grams, that is, the mass ratio of silane coupling agent to graphene oxide is 4:1.

[0044] Example 4 The only difference between this embodiment and Example 1 is that the total mass of tetraethoxysilane and silane coupling agent KH-560 in step S2 is 0.15 grams, that is, the mass ratio of their total mass to the mass of modified graphene oxide is 0.3:1.

[0045] Example 5 The only difference between this embodiment and Example 1 is that the total mass of tetraethoxysilane and silane coupling agent KH-560 in step S2 is 1.0 g, that is, the mass ratio of their total mass to the mass of modified graphene oxide is 2:1.

[0046] Example 6 The only difference between this embodiment and Example 1 is that the amount of silane coupling agent KH-550 used in step S3 is 0.6 grams, that is, the mass ratio of SiO2@FGO nano-hybrid to silane coupling agent is about 1:0.6.

[0047] Example 7 The only difference between this embodiment and Example 1 is that the amount of silane coupling agent KH-550 used in step S3 is 3.0 grams, that is, the mass ratio of SiO2@FGO nano-hybrid to silane coupling agent is about 1:3.

[0048] Example 8 The only difference between this embodiment and Embodiment 1 is that the amount of modified SiO2@FGO nano-hybrid added in step S4 is 0.2 grams, which is 0.5% of the resin solid mass.

[0049] Example 9 The only difference between this embodiment and Example 1 is that the total amount of modified SiO2@FGO nano-hybrid added in step S4 is 1.6 grams, which is 4.0% of the resin solid mass.

[0050] Example 10 The only difference between this embodiment and Example 1 is that the composition of the acrylate monomers is: 30g of methyl methacrylate, 20g of butyl acrylate, 5g of styrene, and 5g of acrylic acid; and the amount of silane coupling agent KH-570 is 3g.

[0051] Comparative Example 1 This comparative example provides a method for preparing a pure acrylic resin coating for performance comparison with the embodiments of the present invention. The specific steps are as follows: Under nitrogen protection, 25 g of methyl methacrylate, 20 g of butyl acrylate, 5 g of hydroxyethyl acrylate, and 50 g of ethyl acetate were added to a reaction vessel, stirred to dissolve, and heated to 80 degrees Celsius. 0.5 g of azobisisobutyronitrile initiator was dissolved in 10 g of ethyl acetate and added dropwise to the reaction system at a uniform rate over 3 hours. After the addition was complete, the reaction was continued at 80 degrees Celsius for 5 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a pure acrylic resin solution without organosilicon modification, with a solid content of approximately 50%. This resin solution was coated onto a substrate, and after curing, a pure acrylic resin coating was formed.

[0052] Experimental Example 1 Test on chloride ion penetration resistance of coated concrete specimens (based on GB / T 50082-2009) The coatings obtained in the above embodiments and comparative examples were applied to the surface of concrete specimens meeting the standard requirements to form a coating of a specified thickness. After the specimens were cured to the specified age, they were tested according to Section 7.2 "Electrical Flux Method" of the "Standard for Test Methods of Long-Term Performance and Durability of Ordinary Concrete" (GB / T 50082-2009). This method evaluates the coating's resistance to chloride ion penetration by measuring the total electrical flux (coulombic value, C) passing through the concrete specimen under a 60V DC voltage for 6 hours. The smaller the electrical flux value, the better the coating's resistance to chloride ion penetration.

[0053] The results of the 6-hour electrical flux test (C) are shown in Table 1: The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An organosilicon-modified acrylic resin coating, characterized in that, Including the following parts by weight of raw materials: 92-99 parts of silicone-modified acrylic resin and 1-8 parts of modified SiO2@FGO nano-hybrid.

2. The organosilicon-modified acrylic resin coating according to claim 1, characterized in that, The preparation method of the modified SiO2@FGO nano-hybrid is as follows: S1. Graphene oxide is dispersed in deionized water and ultrasonically treated to obtain a graphene oxide dispersion; then a silane coupling agent hydrolysate is added and heated to react; after the reaction is completed, modified graphene oxide is obtained through post-treatment. S2. Modified graphene oxide was dispersed in an aqueous ethanol solution and the pH was adjusted. Then, a mixed solution of tetraethoxysilane and silane coupling agent was added dropwise while stirring the reaction. After the reaction was completed, SiO2@FGO nano-hybrids were obtained through post-treatment. S3. Add SiO2@FGO nanohybrids to a silane coupling agent solution and heat to react; after the reaction is completed, post-treatment is performed to obtain modified SiO2@FGO nanohybrids.

3. The organosilicon-modified acrylic resin coating according to claim 2, characterized in that, The concentration of the graphene oxide dispersion in S1 is 0.05–2.0 mg / mL.

4. The organosilicon-modified acrylic resin coating according to claim 2, characterized in that, The mass ratio of silane coupling agent to graphene oxide in S1 is (0.2-8):

1.

5. The organosilicon-modified acrylic resin coating according to claim 1, characterized in that, The mass ratio of the mixed solution to the modified graphene oxide in S2 is (0.1-3):

1.

6. The organosilicon-modified acrylic resin coating according to claim 1, characterized in that, The mixed solution in S2 is prepared by mixing tetraethoxysilane and silane coupling agent in a molar ratio of (0.5-5):

1.

7. The organosilicon-modified acrylic resin coating according to claim 1, characterized in that, In step S2, the pH is adjusted to 8-11; the pH is adjusted using 1-28 wt.% ammonia, 0.1-1 mol / L sodium hydroxide solution, or 5-25 wt.% tetramethylammonium hydroxide solution.

8. The organosilicon-modified acrylic resin coating according to claim 1, characterized in that, The mass ratio of SiO2@FGO nanohybrid to silane coupling agent in S3 is (0.5~5):1; the concentration of silane coupling agent solution is 0.5~15 wt.%.

9. The method for preparing the organosilicon-modified acrylic resin coating according to any one of claims 1-3, characterized in that, Includes the following steps: Weigh the raw materials according to their weight. Organosilicon-modified acrylic resin was dissolved in a solvent and mixed with modified SiO2@FGO nano-hybrids. The mixture was then mechanically stirred and ultrasonically dispersed to obtain an organosilicon-modified acrylic resin coating. The mechanical stirring speed is 200-2000 rpm, and the mechanical stirring time is 0.25-3 hours; the ultrasonic dispersion time is 5-90 minutes.

10. The application of the organosilicon-modified acrylic resin coating of claim 1 in the surface protection of marine reinforced concrete engineering.

Images