High-efficiency energy-saving ship section shell outfitting and coating integrated process

Abstract

The application relates to the technical field of ship anticorrosive coating, and discloses a high-efficiency energy-saving ship section shell outfitting and coating integrated process, which comprises the following steps: preparing component A containing bisphenol A type epoxy resin and other raw materials; using acetylacetone to dynamically seal the phenolic hydroxyl group of cashew nut shell oil modified phenolic amine, adding ketimine and polyamide wax micro powder to prepare component B; mixing the two components in a high-pressure airless spraying machine, maintaining the pipeline working pressure at 15.0-20.0 MPa; spraying the mixed coating after the mixed coating flows through an inline heater and is heated to 43-47 DEG C, using pressure drop to cause adiabatic expansion, making acetylacetone flash vaporization to unseal the catalytic sites, and absorbing latent heat to reconstruct the thixotropic network. The application solves the problems of slow crosslinking and curing, easy water absorption and whitening of paint film in a low-temperature and high-humidity environment, and gel blocking in the pipeline of the spraying equipment, realizes the combination of long pot life in the equipment and rapid setting and curing of the film on the surface of the base material.

Description

Technical Field

[0001] This invention relates to the field of ship anti-corrosion coating technology, specifically to an integrated process for outfitting and coating of ship hull sections with high efficiency and energy saving. Background Technology

[0002] Shipbuilding commonly employs a sectional construction method, and anti-corrosion coating is a crucial step in ensuring the service life of a vessel. In conventional shipbuilding processes, hull sections and outfitting components typically require separate surface treatment and multiple thin-layer coating operations. This method involves lengthy processes and frequent material turnover. To improve construction efficiency, shipyards are gradually introducing integrated hull-outfitting-coating technology. This process requires two-component anti-corrosion coatings to achieve thick film standards through a single high-pressure airless spraying, thereby reducing the number of application layers.

[0003] Currently, heavy-duty corrosion protection for ships mainly relies on two-component epoxy coating systems. Shipbuilding bases are mostly located in coastal areas, often facing a climate environment of low temperature and high humidity during winter construction. Under these operating conditions, the molecular chain movement of conventional epoxy systems is hindered, and the cross-linking reaction rate drops sharply, resulting in a significant increase in the surface drying and complete drying time of the paint film. High concentrations of moisture in the environment can also penetrate into the incompletely cross-linked wet film, reacting with the amine curing agent in the system to generate amine salts, which then precipitate, causing whitening defects on the coating surface and damaging the adhesion between the coating and the steel substrate.

[0004] To overcome the slow curing caused by low temperatures, existing technologies typically use highly reactive curing agents or add large amounts of chemical accelerators. However, this approach results in excessively high activity in two-component coatings after mixing, drastically shortening their pot life. When using high-pressure airless spraying equipment, the mixed coating is highly susceptible to early cross-linking and rapid gelation within the sealed pressurized pipeline, causing blockages or even rendering the expensive equipment unusable. Attempting to reduce the viscosity of high-solids coatings by heating the pipeline to maintain atomization further accelerates the risk of gelation in dead zones within the equipment due to thermodynamic forces. Existing marine coating processes and materials cannot simultaneously achieve both long pot life within sealed equipment and rapid cross-linking and curing on low-temperature, high-humidity substrate surfaces, making it difficult to guarantee continuous operation under harsh climatic conditions. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an efficient and energy-saving integrated outfitting coating process for ship hull sections. It solves the problems of slow cross-linking and curing of existing ship anti-corrosion coatings in low-temperature and high-humidity environments, easy water absorption and whitening of the paint film, and the fact that increasing curing activity can lead to early gelation and blockage of two-component coatings in closed spraying equipment pipelines, making it difficult to balance the long service life inside the equipment with rapid thick film formation on the substrate surface.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections, comprising the following steps: Bisphenol A type epoxy resin, reactive diluent and mixed solvent are dispersed, and anti-rust pigment and extender filler are added in sequence. After high-speed dispersion and grinding to the specified fineness, component A is obtained. Cashew shell oil-modified phenolic amine was mixed with acetylacetone, and the phenolic hydroxyl groups were dynamically capped by acetylacetone. Then, ketoimine and n-butanol were added, and finally polyamide wax micro powder was added to disperse the mixture to obtain component B. The components A and B are added to a high-pressure airless sprayer according to the specified ratio and mechanically stirred until homogeneous. The hydraulic pump is set to maintain the working pressure of the fluid in the pipeline at 15.0 to 20.0 MPa. The mixed components A and B form a coating that is rapidly heated to 43 to 47 degrees Celsius by an inline heater and then sprayed out. The pressure drop inside and outside the nozzle causes adiabatic expansion, which causes acetylacetone to flash vaporize instantly to unblock the catalytic sites. At the same time, it absorbs latent heat to induce thixotropic network reconstruction, and finally achieves rapid shaping and curing of film on the substrate surface.

[0007] By adopting the above technical solution, and by combining a specific chemical end-capping mechanism with a fluid dynamics phase change process, the physical and chemical kinetic barriers to rapid film formation of coatings under low temperature and high humidity conditions are overcome. Therefore, the effect of extending the service life of the spraying equipment and greatly accelerating the curing of the substrate surface is achieved. The reaction process and innovative film-forming mechanism of this invention specifically include the following steps: Step 1: Dynamic Hydrogen Bond Latent Shielding Process: During the preparation of component B, acetylacetone, acting as a proton acceptor with tautomer properties, forms strong intermolecular dynamic hydrogen bonds with the free phenolic hydroxyl groups in the cashew nut shell oil-modified phenolic amine structural unit. The catalytically active sites of the phenolic hydroxyl groups are thus locked in place by both steric hindrance and charge transfer. Under these conditions, the proton-driven cross-linking and curing reaction within the system stagnates, ensuring that the two-component mixed coating maintains low viscosity and a long pot life within room-temperature, sealed equipment pipelines, thus mitigating the risk of gel spoilage within high-pressure pipelines.

[0008] Step Two: In-line Pressurization and Transient Heating: The high-pressure airless spraying equipment forcibly increases the fluid pressure to 15.0–20.0 MPa. The coating passes through the in-line heater in a laminar flow state. Due to the short heating zone and extremely high flow rate, the overall temperature of the coating system instantly rises to 43–47°C. The ultra-high pressure physical state significantly increases the boiling point of the volatile components in the mixture, preventing acetylacetone and n-butanol molecules from crossing the gas-liquid interface. The coating viscosity decreases sharply with increasing temperature, establishing suitable rheological preconditions for extremely high atomization requirements.

[0009] Step 3: Adiabatic Expansion Vaporization and Targeted Unsealing: The liquid coating flows through the micro-orifices at the spray gun end and is ejected, causing the ambient pressure to drop instantly from ultra-high pressure to normal pressure. This huge pressure drop completely destroys the thermodynamic equilibrium inside the fluid, triggering a violent adiabatic expansion effect. The acetylacetone molecules, which have a low boiling point and are already in a preheated high-temperature state, undergo flash vaporization within milliseconds of exiting the nozzle. This violent physical phase transition process directly tears apart the originally maintained dynamic hydrogen bond network, completely releasing the free phenolic hydroxyl groups in the modified phenolic amine structure and re-exposing the catalytic active sites.

[0010] Step Four: Latent Heat Absorption Cooling and Thixotropic Network Reconstruction. The flash vaporization process of acetylacetone forcibly absorbs a large amount of latent heat within the system, causing a sharp drop in temperature of the atomized paint droplets upon adhesion to the substrate surface. The low temperature immediately restricts the disordered thermal motion of the resin macromolecular chains, while the polyamide wax micropowder distributed within the system rapidly restores hydrogen bond association in the low-temperature environment, rebuilding a highly supportive three-dimensional thixotropic network. This rheological control achieved through phase change cooling completely eliminates the tendency for sagging under gravity during thick coating application.

[0011] Step 5: Moisture-Induced Catalytic Hydrolysis and Deep Crosslinking: Free phenolic hydroxyl groups, freed from hydrogen bond shielding, act as highly efficient proton donors, exhibiting strong catalytic activity under low-temperature boundary conditions. In a high-humidity environment, a large number of water molecules penetrate the surface and interior of the wet film. Driven by the protonation catalysis of the phenolic hydroxyl groups, the latent methyl isobutyl ketone-derived ketimine rapidly undergoes irreversible hydrolysis. The reaction is as follows: the ketimine molecule decomposes with water, generating an active primary amine and the byproduct methyl isobutyl ketone volatilizes. The nascent, highly active primary amine groups generated by hydrolysis, along with the original phenolic amine molecules, undergo nucleophilic ring-opening addition reactions with the epoxy groups in the bisphenol A type epoxy resin backbone.

[0012] The reaction unfolds as follows: the active hydrogen atoms on the amine group attack the epoxy three-membered ring structure, causing the epoxy ring to break and crosslink, generating a polymer macromolecule with a highly dense network structure. The higher the ambient humidity, the greater the concentration gradient of water molecules penetrating the coating, and the stronger the driving force for the hydrolysis of the ketimine to produce the curing agent. This mechanism completely overturns the limitation of traditional heavy-duty anti-corrosion systems that are afraid of moisture, transforming unfavorable moisture in the environment into reactants that promote chemical curing, achieving efficient crosslinking and paint film drying under low-temperature and extremely high-humidity weather conditions.

[0013] Preferably, component A is made from raw materials comprising the following parts by weight: 35 to 40 parts of bisphenol A type epoxy resin; 5 to 10 parts of 1,4-butanediol diglycidyl ether; Mixed solvent 5 to 25 parts; 25 to 35 parts of flaky mica iron ore; 5 to 7.5 parts talc; Precipitate 5 to 7.5 parts of barium sulfate.

[0014] Component B is made from raw materials comprising the following parts by weight: 20 to 25 parts of cashew shell oil modified with phenolic amine; 3 to 6 parts of acetylacetone; 50 to 58 parts of methyl isobutyl ketone-derived ketimine; 9 to 25 parts of xylene; 2 to 5 parts of polyamide wax powder; The mixed solvent is xylene and n-butanol in a weight ratio of 7:3; The amount of acetylacetone added is such that the molar ratio of acetylacetone to the phenolic hydroxyl groups in the cashew nut shell oil-modified phenolic amine is 0.50 to 0.80 to 1.0; the mixing ratio of component A and component B is such that the ratio of the total equivalent of epoxy groups to the total equivalent of active hydrogen is 1.0 to 0.90 to 0.95.

[0015] By adopting the above technical solution, a baseline for the chemical composition ratio supporting the dual mechanisms of flash evaporation and hydrolysis solidification was established.

[0016] 1,4-Butanediol diglycidyl ether, as a bifunctional reactive diluent, reduces the viscosity of the main chain while fully participating in the construction of the curing network, avoiding the shrinkage stress of the paint film caused by the free flow of monofunctional diluent materials. The flake-like mica-iron ore layers are arranged in parallel during the paint film curing and settling process, constructing a tortuous physical maze effect that blocks the vertical penetration path of the corrosive medium and free chloride ions in the later stages.

[0017] The addition of n-butanol improves the compatibility and stability of the epoxy macromolecule and amine curing agent system. Strict control of the molar ratio of acetylacetone to phenolic hydroxyl groups ensures the retention of a very small amount of uncapped phenolic hydroxyl groups to maintain basic rheological compatibility in the initial stage of component mixing, while also sufficient to shield most catalytic sites to meet pot life requirements. Setting the total equivalent of active hydrogen slightly lower than the equivalent of epoxy groups ensures that the macromolecular chain segments have an appropriate crosslinking density after curing and network formation, releasing the internal stress generated by curing shrinkage, and giving the coating a flexible buffering ability when subjected to external pulling forces, thus improving the long-term adhesion strength between the coating and the steel plate anchor pattern interface.

[0018] Preferably, the step of preparing component A specifically includes: Bisphenol A epoxy resin, reactive diluent and mixed solvent are added to a dispersion vessel and stirred at 500 rpm until homogeneous; Add flake-shaped mica iron ore, talc powder and precipitated barium sulfate in sequence, and increase the rotation speed to 1200 to 1500 rpm for high-speed dispersion for 30 to 45 minutes; Pump the mixture into a sand mill and grind it to a fineness of less than or equal to 50 micrometers, then filter and package it to obtain component A. The specific steps for preparing component B include: adding cashew nut shell oil-modified phenolic amine to a nitrogen-protected reactor; adding acetylacetone dropwise at a uniform rate under a temperature controlled at 20 to 25 degrees Celsius for 15 to 20 minutes; stirring continuously at a constant temperature for 45 to 60 minutes after the addition is complete; adding ketimine and n-butanol and stirring at 300 rpm for 20 minutes; slowly adding polyamide wax powder and increasing the rotation speed to 800 to 1000 rpm to disperse for 20 to 30 minutes; and then sealing and packaging to obtain component B.

[0019] By adopting the above technical solutions, the manufacturing process was standardized to ensure the stability of the microscopic physical structure and the chemical latent state. High-speed shearing and grinding processes thoroughly broke down the hard agglomerates of the rust-inhibiting pigments and fillers, ensuring complete wetting and coating of the resin liquid onto the solid particles. Pure nitrogen gas was introduced throughout the manufacturing of component B, eliminating the premature activation and degradation of the latent state of the ketimine by free moisture in the air. Controlling the addition of acetylacetone at an extremely low rate and maintaining a constant temperature and stirring for a long time within a specific room temperature range provided sufficient thermodynamic time for the orderly rearrangement and repositioning of hydrogen bonds. The post-addition process of polyamide wax micropowder at a specific rotation speed limited the high-shear frictional heat generation from exceeding its activation threshold temperature, ensuring that the rheological parameters of the finished product did not drift during long-term storage.

[0020] Preferably, in the step of adding component A and component B to the high-pressure airless sprayer and mechanically stirring them evenly, the mechanical stirring is carried out at a speed of 200 to 300 rpm for 10 minutes; the mixed coating flows through an inline heater installed 0.4 to 0.6 meters away from the spray gun nozzle, and the temperature rises from the initial ambient temperature to 43 to 47 degrees Celsius within 1.5 to 2.5 seconds; a standard airless nozzle with an orifice diameter of 0.017 to 0.021 inches and a spray angle of 40 to 60 degrees is selected for spraying, and the spray gun movement speed is controlled so that the wet film thickness of a single spray reaches 250 to 350 micrometers.

[0021] By employing the above technical solution, the key fluid dynamics and thermodynamics parameters for inducing phase change were fixed. The inline heater, installed at a limited distance near the end nozzle, controlled the residence time of the high-temperature fluid within the closed pipeline. The rapid heating range of 1.5 to 2.5 seconds not only reduced viscosity but also eliminated the probability of early intermolecular cross-linking side reactions induced by high temperatures.

[0022] The precisely selected nozzle orifice diameter, combined with the set spray angle, generates an optimized atomization pressure drop gradient, ensuring that the sealing agent reaches the maximum flash vaporization rate the moment it leaves the metal micropores. This eliminates the severe plasticization damage caused by small molecules remaining inside the paint film, providing construction parameter guarantees for the one-time formation of a high-density, defect-free coating film with a thickness of 300 micrometers.

[0023] Preferably, the preparation steps of the cashew nut shell oil modified phenolic amine specifically include: Cashew nut shell oil and diethylenetriamine were added to a reactor equipped with a reflux condenser and a water separator at a molar ratio of 1.0:1.2 to 1.5. Nitrogen gas was introduced for protection, and stirring was started while the temperature was raised to 60 to 70 degrees Celsius. Paraformaldehyde was added in portions at a uniform rate, with a molar ratio of paraformaldehyde to cashew nut shell oil of 1.2 to 1.5:1.0. The feeding rate was controlled to maintain the temperature inside the reactor below 80 degrees Celsius. After the feeding was completed, the system was heated to 90 to 110 degrees Celsius and the reaction was maintained at this temperature for 2.5 to 3.0 hours. The reactor was then switched to vacuum distillation mode, and water and unreacted free amines were removed under a vacuum of -0.08 to -0.09 MPa until no distillate was obtained. The product was cooled and discharged to obtain cashew nut shell oil modified phenolic amine. The specific steps for preparing the methyl isobutyl ketone-derived ketimine include: adding ethylenediamine and methyl isobutyl ketone at a molar ratio of 1.0 to 2.2 to 2.5 into a reflux reactor equipped with a water separator; heating to 110 to 130 degrees Celsius under reflux, where the water generated in the reaction forms an azeotrope with the methyl isobutyl ketone, which is then condensed and separated into layers in the water separator. The lower layer of water is discharged, and the upper layer of methyl isobutyl ketone is refluxed back into the reactor; the reaction continues for 4 to 6 hours until no water droplets are generated in the water separator; excess methyl isobutyl ketone is recovered by vacuum distillation, and the mixture is cooled to 40 to 50 degrees Celsius and then filtered to obtain the methyl isobutyl ketone-derived ketimine.

[0024] By employing the above technical solutions, molecular impurities were eliminated at the source of basic resin synthesis, and target functional groups were implanted. The long-chain unsaturated aliphatic side groups within the cashew phenol structure endow the Mannich condensate with excellent internal toughening and wettability to hydrophobic steel substrates. The batch-addition of paraformaldehyde suppressed the molecular chain carbonization byproducts caused by the instantaneous and intense exothermic reaction during the polymerization process. The high-vacuum vacuum distillation stage thoroughly removed residual low-molecular-weight free amines from the system, cutting off the pathway for these highly polar small molecules to precipitate onto the surface and absorb ambient carbon dioxide to form whitened amine salts during the coating curing period. The ketimine synthesis stage utilized a reflux azeotropic dehydration process, continuously removing byproduct moisture through excess low-boiling-point ketones, forcing the chemical equilibrium to shift completely to the right-hand condensation direction, ensuring that the final compound possesses extremely high potential amine activity and a sensitive ability to dehumidify the environment.

[0025] Preferably, in the step of achieving rapid shaping and curing film formation on the substrate surface, the substrate pretreatment and construction environment meet the following conditions: The substrate is a steel plate and outfitting parts that have undergone sandblasting and rust removal treatment. The surface roughness of the substrate is controlled between 50 and 75 micrometers. The ambient temperature during the spraying operation is controlled between 5 and 15 degrees Celsius. The relative humidity during the spraying operation is controlled between 50% and 95%.

[0026] By adopting the above technical solution, the boundary conditions for this new coating process to resist polar climates were clarified. The surface roughness of 50 to 75 micrometers increases the specific surface area of ​​the metal substrate, providing sufficient physical and mechanical interlocking anchor depth for low-viscosity atomized droplets. Conventional heavy-duty anti-corrosion systems approach their reaction dormancy point at 5 degrees Celsius and are prone to condensation at 95% relative humidity, leading to zero adhesion. This technology, relying on a synergistic mechanism of endogenous catalysis and hydrolysis unsealing, eliminates the destructive micro-water film that penetrates to the interface, successfully overcoming the temperature and humidity no-fly zones of traditional industrial coating manuals. This ensures continuous, all-weather coating operations for shipbuilding hull sections and outfitting components in harsh winter and spring environments.

[0027] This invention provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections. It offers the following advantages: 1. This invention employs acetylacetone to dynamically hydrogen-bond the phenolic hydroxyl groups of cashew nutshell oil-modified phenolic amine. Combined with high-pressure airless spraying and in-line heating technology, the coating undergoes adiabatic expansion upon exiting the nozzle, promoting flash vaporization of the sealing agent. The catalytically active sites are shielded within a sealed pipeline at room temperature, preventing early cross-linking and gelation of the two-component mixed coating within the equipment. Furthermore, the catalytic shielding is removed after the coating exits the nozzle and vaporizes, allowing the cross-linking reaction to occur rapidly on the substrate surface. This solves the construction problem of balancing rapid film formation and curing of heavy-duty anti-corrosion coatings with the long service life of equipment.

[0028] 2. This invention introduces methyl isobutyl ketone-derived ketimine to coordinate with unsealed free phenolic hydroxyl groups, constructing a deep curing system synergistically driven by moisture-induced hydrolysis and proton catalysis. Under the catalytic drive of the free phenolic hydroxyl groups, the ketimine on the coating surface and inside absorbs water molecules from the external environment and undergoes an irreversible hydrolysis reaction, generating active primary amines that then crosslink with the epoxy resin backbone. This transforms environmental moisture, which easily leads to whitening or decreased adhesion in traditional coating processes, into reactants that promote chemical crosslinking, overcoming the obstacles of low temperature and high humidity environments to curing kinetics and ensuring the quality of continuous coating operations under conditions of 5℃ and 95% relative humidity.

[0029] 3. This invention utilizes the physical phase change characteristic of acetylacetone during flash vaporization, which absorbs latent heat, to establish a rheological control system in conjunction with polyamide wax micropowder. When the atomized coating droplets adhere to the substrate surface, they rapidly cool due to latent heat absorption, restricting the thermal motion of the liquid resin macromolecular chain segments. Simultaneously, the polyamide wax micropowder rapidly restores hydrogen bond association under cooling conditions, reconstructing a supportive thixotropic network within the coating. This physical shaping mechanism, achieved through phase change cooling, effectively suppresses coating sagging on vertical surfaces or complex outfitting components, meeting the requirement for single-coat, one-time formation of a thick anti-corrosion coating. Attached Figure Description

[0030] Figure 1Viscosity variation curve for verifying the thermodynamic end-cap stability of the storage tank of the present invention; Figure 2 This is a comparison diagram of the verification test of the adiabatic expansion flash evaporation and endothermic quenching mechanism of the present invention; Figure 3 This is a comparative test diagram showing the edge retention rate and anti-sagging performance of the complex outfitting components of this invention; Figure 4 This is a comparative graph showing the curing kinetics test results of the present invention under extreme low temperature and high humidity conditions; Figure 5 This is a comparison chart of the physical and mechanical properties and long-term anti-corrosion performance of the coating of the present invention. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0032] The main raw materials and reagents used in the following examples and comparative examples have the following sources and specifications. Reagents not specifically mentioned are all commercially available analytical grade or higher grade products.

[0033] 1,4-Butanediol diglycidyl ether is an active diluent, CAS number 2425-79-8.

[0034] Talc powder is used as a filler with a particle size of 800 mesh and CAS number 14807-96-6.

[0035] The filler material is precipitated barium sulfate with a particle size of 1000 mesh and CAS number 7727-43-7.

[0036] Xylene is a mixed solvent, with CAS number 1330-20-7.

[0037] n-Butanol is used as the solvent, and the CAS number is 71-36-3.

[0038] Cashew phenol is mainly a mixture of 3-pentadecantenylphenol, in which the total proportion of components with single double bonds, double double bonds and triple double bonds in the side chain is ≥90%, the hydroxyl value is 180-200mgKOH / g, and the CAS number is 8007-24-7.

[0039] Paraformaldehyde is a solid powder with a formaldehyde content of ≥92%, and its CAS number is 30525-89-4.

[0040] Diethylenetriamine is an industrial-grade raw material with CAS number 111-40-0.

[0041] Acetylacetone is a dynamic hydrogen-bonded end-capping agent that exists in a tautomerism equilibrium between keto and enol forms at room temperature. Its boiling point is 140℃ and its CAS number is 123-54-6.

[0042] The anti-rust pigment is flake-shaped mica iron ore, and the filler is talc powder and precipitated barium sulfate.

[0043] Preparation Examples 1-6: Preparation Example 1: This preparation example provides a method for preparing cashew nut shell oil-modified phenolic amine, including the following steps: Cashew phenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a water separator at a molar ratio of 1.0:1.35. Nitrogen gas was introduced for protection, stirring was started and the temperature was raised to 65°C. Paraformaldehyde was added in three batches at a uniform rate, with a molar ratio of paraformaldehyde to cashew phenol of 1.35:1.0. The feeding rate was controlled to maintain the temperature inside the reactor at no more than 80°C. After the feeding is complete, heat the system to 100°C and maintain the temperature for 2.5 hours. The process was changed to vacuum distillation mode, and the water and unreacted free amine generated in the reaction were removed under a vacuum of -0.08MPa until no distillate was produced. The product was then cooled and discharged to obtain cashew shell oil modified phenolic amine with an amine value of 325mgKOH / g.

[0044] Preparation Example 2: This preparation example provides a method for preparing cashew nut shell oil-modified phenolic amine, including the following steps: Cashew phenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a water separator at a molar ratio of 1.0:1.2. Nitrogen gas was introduced for protection, stirring was started and the temperature was raised to 60°C. Paraformaldehyde was added in three batches at a uniform rate, with a molar ratio of paraformaldehyde to cashew phenol of 1.2:1.0. The feeding rate was controlled to maintain the temperature inside the reactor below 80°C. After the feeding is complete, the system is heated to 90°C and kept at that temperature for 3.0 hours. The process was changed to vacuum distillation mode, and the water and unreacted free amine generated in the reaction were removed under a vacuum of -0.09MPa until no distillate was produced. The product was then cooled and discharged to obtain cashew shell oil modified phenolic amine with an amine value of 300mgKOH / g.

[0045] Preparation Example 3: This preparation example provides a method for preparing cashew nut shell oil-modified phenolic amine, including the following steps: Cashew phenol and diethylenetriamine were added to a reactor equipped with a reflux condenser and a water separator at a molar ratio of 1.0:1.5. Nitrogen gas was introduced for protection, stirring was started and the temperature was raised to 70°C. Paraformaldehyde was added in four batches at a uniform rate, with a molar ratio of paraformaldehyde to cashew phenol of 1.5:1.0. The feeding rate was controlled to maintain the temperature inside the reactor below 80°C. After the addition of materials is complete, the system is heated to 110°C and kept at that temperature for 2.5 hours. The process was changed to vacuum distillation mode, and the water and unreacted free amine generated in the reaction were removed under a vacuum of -0.085MPa until no distillate was produced. The product was then cooled and discharged to obtain cashew shell oil modified phenolic amine with an amine value of 350mgKOH / g.

[0046] Preparation Example 4: This preparation example provides a method for preparing a methyl isobutyl ketone-derived ketimine, comprising the following steps: Ethylenediamine and methyl isobutyl ketone were added to a reflux reactor equipped with a water separator in a molar ratio of 1.0:2.35. The mixture is heated to 120°C and refluxed. The water generated in the reaction forms an azeotrope with methyl isobutyl ketone. After condensation, the mixture separates into layers in a water separator. The lower layer of water is continuously discharged, while the upper layer of methyl isobutyl ketone is refluxed back into the reactor. Continue the reaction for 5 hours, until no more water droplets are produced in the distributor; Excess methyl isobutyl ketone was recovered by vacuum distillation, cooled to 45°C, and filtered to obtain a methyl isobutyl ketone-derived ketimine with a potential amine value of 425 mg KOH / g.

[0047] Preparation Example 5: This preparation example provides a method for preparing a methyl isobutyl ketone-derived ketimine, comprising the following steps: Ethylenediamine and methyl isobutyl ketone were added to a reflux reactor equipped with a water separator at a molar ratio of 1.0:2.2. The mixture is heated to 110°C and refluxed. The water generated in the reaction forms an azeotrope with methyl isobutyl ketone. After condensation, the mixture separates into layers in a water separator. The lower layer of water is continuously discharged, while the upper layer of methyl isobutyl ketone is refluxed back into the reactor. Continue the reaction for 4 hours, until no more water droplets are produced in the distributor; Excess methyl isobutyl ketone was recovered by vacuum distillation, cooled to 40°C, and filtered to obtain a methyl isobutyl ketone-derived ketimine with a potential amine value of 400 mg KOH / g.

[0048] Preparation Example 6: This preparation example provides a method for preparing a methyl isobutyl ketone-derived ketimine, comprising the following steps: Ethylenediamine and methyl isobutyl ketone were added to a reflux reactor equipped with a water separator at a molar ratio of 1.0:2.5. The mixture is heated to 130°C and refluxed. The water generated in the reaction forms an azeotrope with methyl isobutyl ketone. After condensation, the mixture separates into layers in a water separator. The lower layer of water is continuously discharged, while the upper layer of methyl isobutyl ketone is refluxed back into the reactor. Continue the reaction for 6 hours, until no more water droplets are produced in the distributor; Excess methyl isobutyl ketone was recovered by vacuum distillation, cooled to 50°C, and filtered to obtain a methyl isobutyl ketone-derived ketimine with a potential amine value of 450 mg KOH / g.

[0049] Examples 1-4: Example 1: This embodiment provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections, including the following steps: Step 1: Preparation of Component A: 40 parts by weight of bisphenol A type epoxy resin, 7.5 parts by weight of 1,4-butanediol diglycidyl ether, and 7.5 parts by weight of a mixed solvent were added to an explosion-proof dispersion vessel and stirred at 500 rpm until homogeneous. The mixed solvent was xylene and n-butanol in a weight ratio of 7:3. 30 parts by weight of flaky mica iron ore, 7.5 parts by weight of talc powder, and 7.5 parts by weight of precipitated barium sulfate were added sequentially. The speed was increased to 1500 rpm for high-speed dispersion for 45 minutes. Subsequently, the mixture was pumped into a sand mill and ground until the fineness was less than or equal to 50 μm. The mixture was then filtered and packaged to obtain Component A for later use.

[0050] Step 2: Preparation of Component B: In a dry, nitrogen-protected reactor, 22 parts by weight of cashew nut shell oil-modified phenolic amine prepared in Preparation Example 1 were added; under the condition of temperature control at 22°C, 4.5 parts by weight of acetylacetone were added dropwise at a uniform rate over a time of 18 minutes, with the molar ratio of acetylacetone to the phenolic hydroxyl group in the phenolic amine being 0.65:1.0; after the addition was complete, the mixture was stirred at a constant temperature for 50 minutes; 58 parts by weight of methyl isobutyl ketone-derived ketimide prepared in Preparation Example 4 and 12 parts by weight of xylene were added, and the mixture was stirred at 300 rpm for 20 minutes; 3.5 parts by weight of polyamide wax powder were slowly added, and the stirring speed was increased to 900 rpm for dispersion for 25 minutes. The mixture was then sealed and packaged in a moisture-proof container to obtain Component B for later use.

[0051] Step 3: Two-component mixing and integrated spraying: Add component A and component B to the feed buffer tank of the high-pressure airless sprayer at a ratio of 1.0:0.95 (total equivalent of epoxy groups to total equivalent of active hydrogen in the system), and mechanically stir at 250 rpm for 10 minutes; set the hydraulic pump of the high-pressure airless sprayer to maintain the working pressure of the fluid in the pipeline at 17.5 MPa; the coating flows through the in-line heater installed 0.5 meters away from the spray gun nozzle, and the temperature rises from the initial ambient temperature to 45°C within 2 seconds; select a standard airless nozzle with an orifice diameter of 0.019 inches and a spray angle of 50°, and spray the coating onto the surface of the steel plate substrate and outfitting parts at an ambient temperature of 5°C and a relative humidity of 65%; control the spray gun movement speed to achieve a wet film thickness of 300 μm for a single spray, and then cure into a film.

[0052] Example 2: This embodiment provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections, including the following steps: Step 1: Preparation of Component A: 35 parts by weight of bisphenol A type epoxy resin, 5 parts by weight of 1,4-butanediol diglycidyl ether, and 25 parts by weight of mixed solvent were added to an explosion-proof dispersion vessel and stirred at 500 rpm until homogeneous. The mixed solvent was xylene and n-butanol in a weight ratio of 7:3. 25 parts by weight of flaky mica iron ore, 5 parts by weight of talc powder, and 5 parts by weight of precipitated barium sulfate were added sequentially. The speed was increased to 1200 rpm for high-speed dispersion for 30 minutes. Subsequently, the mixture was pumped into a sand mill and ground until the fineness was less than or equal to 50 μm. The mixture was then filtered and packaged to obtain Component A for later use.

[0053] Step 2: Preparation of Component B: In a dry, nitrogen-protected reactor, 20 parts by weight of cashew nut shell oil-modified phenolic amine prepared in Preparation Example 2 were added; under the condition of temperature control at 20°C, 3 parts by weight of acetylacetone were added dropwise at a uniform rate for 15 minutes, and the molar ratio of acetylacetone to the phenolic hydroxyl group in the phenolic amine was 0.50:1.0; after the addition was completed, the mixture was stirred at a constant temperature for 45 minutes; 50 parts by weight of methyl isobutyl ketone-derived ketimide prepared in Preparation Example 5 and 25 parts by weight of xylene were added, and the mixture was stirred at 300 rpm for 20 minutes; 2 parts by weight of polyamide wax powder were slowly added, and the stirring speed was increased to 800 rpm for 20 minutes. The mixture was then sealed and packaged in a moisture-proof container to obtain Component B for later use.

[0054] Step 3: Two-component mixing and integrated spraying: Add component A and component B to the feed buffer tank of the high-pressure airless sprayer at a ratio of 1.0:0.90 (total equivalent of epoxy groups to total equivalent of active hydrogen in the system), and mechanically stir at 200 rpm for 10 minutes; set the hydraulic pump of the high-pressure airless sprayer to maintain the working pressure of the fluid in the pipeline at 15.0 MPa; the coating flows through the in-line heater installed 0.4 meters away from the spray gun nozzle, and the temperature rises from the initial ambient temperature to 43°C within 1.5 seconds; select a standard airless nozzle with an orifice diameter of 0.017 inches and a spray angle of 40°, and spray the coating onto the surface of the steel plate substrate and outfitting parts at an ambient temperature of 5°C and a relative humidity of 50%; control the spray gun movement speed to achieve a wet film thickness of 250 μm for a single spray, and then cure into a film.

[0055] Example 3: This embodiment provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections, including the following steps: Step 1: Preparation of Component A: 38 parts by weight of bisphenol A type epoxy resin, 10 parts by weight of 1,4-butanediol diglycidyl ether, and 5 parts by weight of mixed solvent were added to an explosion-proof dispersion vessel and stirred at 500 rpm until homogeneous. The mixed solvent was xylene and n-butanol in a weight ratio of 7:3. 35 parts by weight of flaky mica iron ore, 6 parts by weight of talc powder, and 6 parts by weight of precipitated barium sulfate were added sequentially. The speed was increased to 1500 rpm for high-speed dispersion for 45 minutes. Subsequently, the mixture was pumped into a sand mill and ground until the fineness was less than or equal to 50 μm. The mixture was then filtered and packaged to obtain Component A for later use.

[0056] Step 2: Preparation of Component B: In a dry, nitrogen-protected reactor, 25 parts by weight of cashew nut shell oil-modified phenolic amine prepared in Preparation Example 3 were added; under the condition of temperature control at 25°C, 6 parts by weight of acetylacetone were added dropwise at a uniform rate for 20 minutes, and the molar ratio of acetylacetone to the phenolic hydroxyl group in the phenolic amine was 0.80:1.0; after the addition was completed, the mixture was stirred at a constant temperature for 60 minutes; 55 parts by weight of methyl isobutyl ketone-derived ketimide prepared in Preparation Example 6 and 9 parts by weight of xylene were added, and the mixture was stirred at 300 rpm for 20 minutes; 5 parts by weight of polyamide wax powder were slowly added, and the stirring speed was increased to 1000 rpm for dispersion for 30 minutes. The mixture was then sealed and packaged in a moisture-proof container to obtain Component B for later use.

[0057] Step 3: Two-component mixing and integrated spraying: Add component A and component B to the feed buffer tank of the high-pressure airless sprayer at a ratio of 1.0:0.95 (total equivalent of epoxy groups to total equivalent of active hydrogen in the system), and mechanically stir at 300 rpm for 10 minutes; set the hydraulic pump of the high-pressure airless sprayer to maintain the working pressure of the fluid in the pipeline at 20.0 MPa; the coating flows through the in-line heater installed 0.6 meters away from the spray gun nozzle, and the temperature rises from the initial ambient temperature to 47°C within 2.5 seconds; select a standard airless nozzle with an orifice diameter of 0.021 inches and a spray angle of 60°, and spray the coating onto the surface of the steel plate substrate and outfitting parts at an ambient temperature of 15°C and a relative humidity of 85%; control the spray gun movement speed to achieve a wet film thickness of 350 μm for a single spray, and then cure into a film.

[0058] Example 4: This embodiment provides a highly efficient and energy-saving integrated outfitting and coating process for ship hull sections, including the following steps: Step 1: Preparation of component A: The preparation steps and parameters are completely consistent with those in Example 1.

[0059] Step 2: Preparation of component B: The preparation steps and parameters are completely consistent with those in Example 1.

[0060] Step 3: Two-component mixing and integrated spraying: Add component A and component B to the feed buffer tank of the high-pressure airless sprayer at a ratio of 1.0:0.95 (total equivalent of epoxy groups to total equivalent of active hydrogen in the system), and mechanically stir at 250 rpm for 10 minutes; set the hydraulic pump of the high-pressure airless sprayer to maintain the working pressure of the fluid in the pipeline at 17.5 MPa; the coating flows through the in-line heater installed 0.5 meters away from the spray gun nozzle, and the temperature rises from the initial ambient temperature to 45°C within 2 seconds; select a standard airless nozzle with an orifice diameter of 0.019 inches and a spray angle of 50°, and spray the coating onto the surface of the steel plate substrate and outfitting parts in an extreme high humidity environment with a temperature of 5°C and a relative humidity of 95%; control the spray gun movement speed to achieve a wet film thickness of 300 μm for a single spray, and then cure into a film.

[0061] Comparative Examples 1-5: Comparative Example 1: Compared with Example 1, the difference is that component B is replaced with a commercially available conventional polyamide curing agent with an equivalent amount of active hydrogen, and in the integrated spraying in step three, the inline heater is turned off and conventional high-pressure airless spraying is performed at room temperature; all other aspects are the same.

[0062] Comparative Example 2: Compared with Example 1, the difference is that in the preparation of component B in step two, acetylacetone is not added at all, that is, the cashew nut shell oil modified phenolic amine is not chemically capped, and everything else is the same.

[0063] Comparative Example 3: Compared with Example 1, the difference is that in the integrated spraying in step three, the inline heater in the pipeline is turned off and the working pressure of the fluid in the pipeline is reduced to 10.0 MPa, so that the pipeline fixed-point temperature control and adiabatic expansion pressure reduction flash evaporation do not occur during the spraying process. All other aspects are the same.

[0064] Comparative Example 4: Compared with Example 1, the difference is that in the preparation of component B in step two, acetylacetone is replaced in equimolar amounts with n-butanol, a conventional volatile solvent that does not have keto-enol tautomerism, while the rest are the same.

[0065] Comparative Example 5: Compared with Example 1, the difference is that in the preparation of component B in step two, the amount of acetylacetone added is greatly increased, so that the molar ratio of acetylacetone to phenolic hydroxyl groups in phenolic amine reaches 1.5:1.0, which far exceeds the set upper limit ratio, while the rest are the same.

[0066] Test Examples 1-5: Test Example 1: Test objective: This test aims to verify the actual effect of the dynamic hydrogen bond end-capping mechanism formed after the introduction of acetylacetone on extending the service life of the coating by monitoring the change of apparent viscosity of the two-component system over time in a closed environment.

[0067] Experimental steps: Weigh out components A and B of Examples 1, 2 and 4 according to the predetermined ratio, place them in an explosion-proof mixing tank equipped with a mechanical stirrer, and stir continuously at 300 rpm for 10 minutes at an ambient temperature of 25°C to fully homogenize and mix the epoxy resin base material and the controlled curing agent system.

[0068] After mixing, each group of coating slurry was quickly dispensed into a standard tinplate test container with a capacity of 500 ml and immediately sealed. Then, it was placed in a constant temperature water bath at a set temperature of 25°C for static aging to simulate the environment of an industrial storage tank.

[0069] The moment of complete mixing is designated as hour 0. At the time points of 0, 1, 2, 4, and 6 hours, the apparent viscosity of the slurry is measured using a rotational viscometer (the test rotor and speed are dynamically matched according to the actual viscosity range). After each test, the slurry is resealed with a new cap and returned to the constant temperature water bath. Viscosity data at different time points are recorded for rheological plotting.

[0070] The experimental results are shown in Table 1:

[0071] in conclusion: Figure 1 This is a viscosity change curve for verifying the thermodynamic end-sealing stability of the storage tank of this invention. The horizontal axis represents the sealed aging time after mixing, and the vertical axis represents the apparent viscosity of the system. The solid line marked with a circle represents Example 1, the dashed line marked with a square represents Comparative Example 2, and the dotted line marked with an upper triangle represents Comparative Example 4.

[0072] According to the data in Table 1, the system without chemical end-capping treatment is highly susceptible to runaway macroscopic rheological properties after mixing. In a conventional closed container and a simulated storage tank environment at 25°C, the apparent viscosity of Comparative Example 2 showed a precipitous increase within 2 hours, exhibiting gelation and stringing characteristics in its actual physical state, completely losing the pipeline leveling and pumping conditions necessary for high-pressure airless spraying. This intense tendency for explosive polymerization stems directly from the highly efficient catalytic effect of free phenolic hydroxyl groups on latent ketimines. Even in a strictly closed system, the trace amounts of bound water carried by the resin and filler are sufficient to break the reaction inertia and trigger a chain reaction of hydrolysis and crosslinking.

[0073] Comparative Example 4, which used the conventional volatile solvent n-butanol for equimolar substitution, also failed to prevent the rapid deterioration of the rheological curve, and its viscosity growth trajectory showed a high degree of convergence with that of Comparative Example 2. The methyl ethyl ketone (MEK) molecule lacks the thermodynamic basis for ketone-enol tautomerism and cannot effectively overlap electron clouds with the phenolic hydroxyl groups of the cashew phenol aldehyde amine molecule to form a chelate structure. Therefore, this additive only plays a simple physical role in reducing viscosity and diluting the microstructure, completely losing its shielding effect on catalytically active sites.

[0074] Example 1 exhibited excellent viscosity inertia during the 6-hour test period. After sufficient sealed aging, its apparent viscosity increase remained within 18% of the initial value, and the overall slurry maintained a state highly suitable for fluid atomization. This long-term stability of rheological parameters directly confirms the physical authenticity and anti-interference ability of the acetylacetone dynamic hydrogen bond end-capping mechanism in the formulation design. Acetylacetone, through its enol configuration and phenolic hydroxyl group, spontaneously assembles into stable six-membered ring chelate hydrogen bonds, successfully freezing the core catalytic center of the curing system in a room-temperature container without relying on external extreme cooling. This temporary locking of microscopic chemical bonds significantly extends the effective activation period of conventional two-component heavy-duty anti-corrosion coatings from an extremely short process limit to meet the industrial needs of continuous single-shift operations in modern shipyards, providing the most critical thermodynamic buffer zone for subsequent targeted unsealing at the nozzle based on pipeline mechanical pressure drop and fixed-point temperature gradient.

[0075] Test Example 2: Test objective: This test aims to verify the acetylacetone flash vaporization phenomenon caused by a specific temperature gradient and pressure drop at the moment when the coating fluid passes through the nozzle at high speed and leaves the pipeline, as well as the rapid reconstruction capability of the thixotropic network triggered by the accompanying endothermic cooling effect.

[0076] Experimental steps: The temperature in the environmental testing chamber was strictly controlled at 5°C. Two-component coatings prepared by mixing Example 1 and Comparative Example 3 were used as test subjects and connected to a high-pressure airless spraying device equipped with an inline heater.

[0077] For Example 1, the heating system was started and the pipeline fluid working pressure was set to 17.5 MPa to allow the coating to reach a preheated and activated state; for Comparative Example 3, the power supply to the inline heater was cut off and the fluid working pressure was adjusted to the conventional 10.0 MPa.

[0078] During steady-state spraying operations, a high-precision infrared thermal imager was used to measure and record the fluid outlet temperature estimated from the outer wall of the exposed pipeline 5 cm directly behind the nozzle, and the droplet flight temperature in the center area of ​​the atomized fan 10 cm directly in front of the nozzle.

[0079] A rheometer parallel plate receiving plate with a surface pre-cooled to 5°C was placed 30 cm away from the nozzle. The coating droplets were quickly scraped flat at the moment they hit the receiving plate, and the oscillation time scanning mode of the rheometer was started. The recovery of the storage modulus was continuously monitored within 60 seconds after the coating was collected under constant frequency and low strain conditions. The test values ​​at three key nodes, namely 10 seconds, 30 seconds and 60 seconds, were recorded.

[0080] The experimental results are shown in Table 2:

[0081] in conclusion: Figure 2 These are comparative graphs showing the verification tests of the adiabatic expansion flash evaporation and endothermic quenching mechanism of this invention. Figure A shows the temperature change from the pipeline to the atomization zone, and Figure B shows the recovery curve of the energy storage modulus of the coating droplets over time. The solid lines and circles in the figures represent Example 1, and the dashed lines and squares represent Comparative Example 3.

[0082] According to the data in Table 2, Example 1 reached the predetermined thermodynamic activation state after passing through the inline heater, and the measured temperature at the pipeline outlet was 44.8°C. However, at the moment when the high-pressure fluid passed through the nozzle and left the sealed pipeline to enter the normal temperature and pressure environment, the droplet temperature dropped to 2.1°C in an extremely abnormal manner.

[0083] This temperature drop is not only far below the initial heating temperature, but also exceeds the 5°C limit of the external working environment temperature. In conventional spraying equipment, this extreme cooling phenomenon often causes localized condensation and micro-frost around the nozzle. The underlying physical driving force is that when acetylacetone in the formula experiences a sudden pressure difference from 17.5 MPa to 1 standard atmosphere, the saturated vapor pressure that was originally suppressed by the system instantly exceeds the equilibrium point, triggering violent adiabatic expansion and vaporization behavior.

[0084] A large amount of latent heat of vaporization was forcibly extracted from the inside of the droplet and carried away with the volatiles, causing the residual heat energy of the system to be rapidly lost. In Comparative Example 3, due to the lack of pre-set temperature accumulation and high pressure conditions, the temperature of its coating before and after exiting the pipe always fluctuated around the environmental baseline, and the phase change endothermic phenomenon was completely not induced.

[0085] The dramatic temperature gradient generated in the atomization zone directly influences the rheological network reconstruction trajectory during the initial impact of the coating on the substrate. The storage modulus recovery data objectively maps the entanglement state of the internal micro polymer chains. In Example 1, the storage modulus of the coating droplet, which characterizes the elastic response strength, rapidly exceeded 1450.3 Pa within 10 seconds after being collected by the collector, and a strong and tough yield structure with a value as high as 5104.2 Pa was constructed within 1 minute.

[0086] The core of this macroscopic thickening phenomenon lies in the fact that when the polyamide wax rheology micropowder, which is forced to thermally dissociate at high temperatures within the pipeline, encounters a low-temperature shock of 2.1°C, the solubility parameters of the surrounding mixed solvent undergo a sudden change, and the mixing solvation effect instantly fails. This forces the discrete amide groups to forcibly reassemble the three-dimensional hydrogen bond network in a manner similar to quenching in metal heat treatment. Comparative Example 3, lacking a physical triggering mechanism, exhibits extremely slow structural evolution within the same time observation window, with its modulus level barely reaching 812.4 Pa at 60 seconds, indicating that the fluid interior is still dominated by viscous flow characteristics. This lag in the establishment of yield stress in the early stages of film formation inevitably transforms into uncontrollable gravity sagging defects in the complex outfitting facade coatings commonly seen in shipyards. The above systematic differences at the microscopic rheological data level fully demonstrate that by artificially creating extreme pressure drops and temperature gradients at the process end to forcibly induce flash evaporation of the end-capping agent, the release of chemical catalytic sites and the freezing of the physical rheological structure can be perfectly aligned on the time axis, providing solid physicochemical support for achieving high-quality thick film construction under low-temperature and high-humidity environments.

[0087] Test Example 3: Test Objective: This test aims to objectively evaluate the actual ability of different formulations and spraying processes to overcome gravity flow and maintain the paint film thickness at the sharp corners of the structure when forming a medium to high thickness wet film by simulating the facade painting scenario of complex geometric components in a shipyard.

[0088] Experimental steps: Standardized 90-degree right-angle test blocks made of Q235 steel were selected, sandblasted to Sa2.5 standard, and surface dust was removed with high-pressure oil-free air. Simulated construction conditions were set in an environmental constant temperature and humidity chamber with a test temperature of 5℃ and a relative humidity of 65%.

[0089] Two-component coatings were prepared and mixed using Examples 1, 2, 3, 4, Comparative Example 1, and Comparative Example 3, respectively, and then connected to a high-pressure airless sprayer with corresponding pipeline pressure and heating parameters set. The spray gun was operated to perform single-pass continuous spraying on the surface of the vertically suspended test block. By controlling the movement speed of the spray gun, the wet film thickness in the main planar area of ​​the test block was controlled within the range of 300 μm to 350 μm.

[0090] After spraying, place the test block on a vertical support. After 10 minutes, use a vernier caliper to measure and record the distance of the lower end of the longest paint drip mark on the vertical surface.

[0091] After the test blocks were cured continuously in the same environment for 7 days until completely dry, an electromagnetic induction coating thickness gauge was used to uniformly select 10 test points at the 90-degree right-angle turning edge of the test block to measure the edge dry film thickness. At the same time, 10 test points were selected on a flat stress surface area 5 cm away from the edge to measure the planar dry film thickness. The arithmetic mean of each set of data was calculated, and the edge retention rate percentage was obtained by dividing the average edge dry film thickness by the average planar dry film thickness.

[0092] The experimental results are shown in Table 3:

[0093] in conclusion: Figure 3 This is a comparative test chart of the edge retention rate and anti-sagging performance of the complex outfitting components of the present invention. A shows the edge retention rate distribution of each group of test objects, and B shows the vertical sagging distance distribution of each group of test objects. The black solid lines and solid circles in the chart represent the numerical trends of the edge retention rate for each embodiment and comparative example, while the dashed lines and hollow upper triangles represent the numerical distribution of the vertical sagging distance.

[0094] According to the data in Table 3, the example group showed a film-forming and shaping capability that was orders of magnitude different from the existing technology when dealing with thick vertical surface spraying operations. In the construction site of shipbuilding heavy anti-corrosion coating, large areas of vertical bulkheads and many outfitting components with sharp angles are often encountered. Traditional epoxy anti-corrosion coatings are prone to corner coating shrinkage and thinning and vertical surface drip accumulation under the action of their own surface tension and gravity field. This directly leads to premature corrosion perforation in the stress concentration area.

[0095] The experimental records clearly show that when the commercially available conventional polyamide curing system in Comparative Example 1 is sprayed with a thickness exceeding 200 μm, the dry film thickness at the right-angled edges is drastically reduced to 62.4 μm, and the edge retention rate is as low as 31.4%. The accompanying severe flow marks, which are as long as 45.2 mm, indicate that the fluid completely lacks a microstructure sufficient to support its own weight.

[0096] Comparative Example 3, which uses the formulation of this invention but does not employ the inline heating and reduced-pressure flash evaporation process, only achieved an edge retention rate of 40.5%, demonstrating that simply adding polyamide wax micropowder to the formulation without activation through a specific thermodynamic process cannot establish an effective anti-sagging network at the moment of film formation. Examples 1 to 4 consistently exhibited high levels of anti-gravity characteristics, with edge retention rates generally maintained above 75%, and Examples 1 and 4 even approaching 85%, while sagging distances were strictly controlled to a negligible 1 mm.

[0097] The essence of this macroscopic phenomenon lies in the endothermic vaporization of acetylacetone upon exiting the nozzle, which causes a precipitous drop in the temperature of the coating droplets. The polyamide wax, initially in a thermally dissociated and free state, experiences a sharp deterioration in solubility parameters at extremely low temperatures. This phase separation tendency forces the amide groups at the wax molecule chain ends to rapidly orient themselves through strong polar attraction, forming a dense three-dimensional hydrogen bond network. Within milliseconds of impacting the steel plate, the droplets are endowed with enormous initial yield stress. This stress network firmly locks the spatial positions of the pigment and filler particles before the solvent n-butanol further evaporates, successfully preventing the creep slip of the liquid coating towards lower potential energy regions, thus achieving uniform thickness coverage of a highly dense anti-corrosion barrier.

[0098] Test Example 4: Test Objective: This test aims to simulate the harsh climatic conditions commonly encountered in coastal shipyards during winter. By tracking the time point of the coating's transition from liquid to solid state, it verifies the kinetic characteristics of the system of this invention in accelerating curing with spatial moisture under low temperature and extreme high humidity conditions. At the same time, it examines the potential negative impact of residual chemical end-capping agents on the final film quality.

[0099] Experimental steps: Prepare multiple standard tinplate test samples that have undergone sandblasting and rust removal. Divide the samples into two groups and place them in two large constant temperature and humidity environment simulation chambers with pre-set parameters. The first simulation chamber is set to a standard low temperature environment with a temperature of 5°C and a relative humidity of 65%. The second simulation chamber is set to an extreme low temperature and high humidity environment with a temperature maintained at 5°C but a relative humidity increased to 95%.

[0100] Components A and B of Examples 1, 4, 1, 3, and 5 were selected as test subjects. Following the predetermined construction process parameters, the mixed two-component coatings were sequentially sprayed onto the surfaces of test specimens in two sets of environmental simulation chambers using a high-pressure airless spraying device. The initial wet film thickness of each specimen was strictly controlled to fluctuate around 300 μm.

[0101] After the spraying operation was completed, the samples remained in their respective environmental simulation chambers for curing. Following the method for determining the drying time of paint film and putty film, timing was started from the moment the spraying was completed. In the early stages, the surface drying time of the coating was measured frequently using the finger-touch method, and the shortest time it took for the paint not to stick to the surface of the coating when the finger was lightly touched was recorded.

[0102] After the coating reaches a surface dry state, the indentation method or tinplate scribing method is used to periodically test the coating's actual drying time, which is the time required for the paint film to be completely cross-linked and cured, able to withstand mechanical pressure without leaving marks. Detailed drying kinetic data for each test object under two sets of climatic conditions are recorded and compiled.

[0103] The experimental results are shown in Table 4:

[0104] in conclusion: Figure 4 These are comparative graphs showing the curing kinetics tests of this invention under extreme low temperature and high humidity conditions. Figure A shows the surface drying and complete drying times under a 5℃ / 65%RH environment, and Figure B shows the surface drying and complete drying times under an extreme high humidity environment of 5℃ / 95%RH. In Figure A, the solid black lines and hollow circles represent the surface drying time of each test object, and the dashed black lines and solid squares represent the complete drying time. In Figure B, the solid black lines and hollow upper triangles represent the surface drying time under extreme high humidity, and the dotted black lines and solid diamonds represent the complete drying time.

[0105] According to the data in Table 4, the chemical crosslinking process of two-component anti-corrosion coatings after leaving the equipment is not only controlled by temperature thermodynamics, but also deeply coupled with the microscopic penetration behavior of water molecules in the environment. In the traditional experience of outdoor coating in shipyards during winter, low temperature usually causes the ring-opening reaction between epoxy resin and amine curing agent to almost stop. The test record of Comparative Example 1 accurately reflects this pain point.

[0106] When exposed to air at 5°C and 65% relative humidity, it takes more than 36 hours to barely reach a fully dry state. In extreme marine environments where the relative humidity rises to 95%, the supersaturated water vapor in the air not only forms a condensed micro-water film on the surface of the paint film, physically hindering the evaporation of the solvent n-butanol, but may also undergo side reactions with unreacted primary amine groups, causing the paint film surface to turn white and sticky, thus significantly delaying its surface drying time to more than 15 hours and fully dry time, respectively.

[0107] In stark contrast to the complete loss of control that conventional systems exhibit in high-humidity environments, Examples 1 and 4 demonstrate a counterintuitive kinetic acceleration phenomenon. These two formulations actually dried faster at 95% RH than at 65% RH, with surface drying time reduced to less than 3 hours and actual drying time stabilized at around 12 hours. This unusually efficient curing stems from a fundamental restructuring of the formulation's underlying logic.

[0108] This solution cleverly utilizes the flash evaporation and desealing mechanism of acetylacetone caused by adiabatic expansion at the nozzle. The previously locked phenolic amine immediately releases highly active phenolic hydroxyl groups. These phenolic hydroxyl groups not only possess low-temperature catalytic capabilities but also act as highly efficient proton donors for the latent ketimine hydrolysis reaction within the system. Higher ambient humidity results in a greater concentration gradient of water molecules penetrating the wet film. Under the strong catalysis of the free phenolic hydroxyl groups, the ketimine rapidly consumes water and dissociates into a large amount of highly active primary amines. This chemical mechanism, which transforms environmental disadvantages (high humidity) into reaction advantages (hydrolysis driving force), completely overturns the limitations of traditional coatings that are passively constrained by climate.

[0109] Simply relying on formulation adjustments while neglecting fluid dynamics will also fail to achieve the desired results. Although Comparative Example 3 had the same chemical composition, the lack of pipeline heating and nozzle pressure drop flash evaporation processes meant that acetylacetone could not be effectively removed from the coating system. The end-capping agent trapped within the paint film resulted in extremely delayed release of phenolic hydroxyl groups, failing to provide sufficient catalytic energy in the early stages of film formation, leading to a doubling of the drying time compared to the examples. Over-reliance on chemical end-capping is also dangerous; the excessive acetylacetone added in Comparative Example 5 could not be completely vaporized at the nozzle, and these small molecule compounds remaining in the polymer network exhibited severe plasticizing effects.

[0110] Even though the system can still barely achieve surface drying with the partially desealed catalyst, the swollen and plasticized three-dimensional cross-linked network severely hinders the further slippage and compaction of resin molecules, directly leading to an abnormally long internal drying time of over 40 hours. Fully controlling the introduction ratio of the end-capping agent and combining it with a customized flash spraying process to completely remove small molecules from the coating are the core boundary conditions for ensuring the primer has an industrial-grade rapid turnaround time.

[0111] Test Example 5: Test objective: This test aims to comprehensively evaluate the micro-crosslinking density, interfacial adhesion to the substrate, and long-term shielding effectiveness against corrosive media penetration of each formulation and process after curing, and to verify whether the invention sacrifices the core mechanical and anti-corrosion indicators of heavy-duty anti-corrosion coatings while pursuing workability and curing speed.

[0112] Experimental steps: Multiple Q235 steel plates with a surface roughness of Rz50-75μm were prepared after sandblasting and rust removal. Two-component coatings prepared using Examples 1 to 4 and Comparative Examples 1 to 5 were used as test subjects. The coatings were uniformly applied to the steel plate surface according to their respective spraying equipment parameters and process conditions. The dry film thickness of each sample was controlled to be approximately 250μm, and the plates were continuously cured for 14 days in a standard experimental environment of 23℃ and 50% relative humidity to ensure complete cross-linking and curing of the macromolecular network.

[0113] After the coating curing was completed, according to the pull-out adhesion test standard, a cylindrical aluminum test cylinder with a diameter of 20 mm was vertically bonded to the surface of the coating film of each sample using a special two-component solvent-free epoxy adhesive. After curing at room temperature for 24 hours, a hydraulic pull-out tester was used to apply a uniform vertical tensile force until the coating was damaged. The critical stress value at the time of pull-out failure was recorded, and the location of the failure section was observed.

[0114] On another batch of test samples prepared under the same conditions, cross-cuts extending to the steel substrate were made into the paint film surface using a sharp scriber. The edges of the scratched samples were sealed with paraffin wax and then placed in a salt spray test chamber, where they were continuously sprayed with a 5% neutral sodium chloride aqueous solution at 35°C.

[0115] After maintaining a neutral salt spray test for 1500 hours, the sample was removed and the salt deposited on the surface was rinsed off with tap water. After drying, the width of the rust spreading outward from the intersection of the scratches was measured with vernier calipers and the final data was recorded in millimeters to characterize the coating’s ability to resist the bottom penetration damage of chloride ions and oxygen.

[0116] The experimental results are shown in Table 5:

[0117] in conclusion: Figure 5 This is a comparison chart of the physical and mechanical properties and long-term anti-corrosion performance of the coating of this invention. Figure A shows the pull-out adhesion distribution of the cured paint film of each group of test objects, and Figure B shows the unidirectional corrosion propagation width distribution of each group of test objects after 1500 hours of salt spray. In Figure A, the black solid line and solid circle represent the pull-out adhesion strength at the interface between the paint film and the substrate, and in Figure B, the black dashed line and hollow square represent the unidirectional corrosion propagation distance at the scratch after 1500 hours of neutral salt spray erosion.

[0118] According to the data in Table 5, the rheological control and chemical reaction kinetics of the coating system in the early stage of film formation directly determine the density of the final three-dimensional polymer network and the distribution of residual internal stress. In the field of marine corrosion protection engineering, there is often a technical compromise: in pursuit of extremely rapid curing, severe volume shrinkage often occurs inside the coating film, which in turn generates cross-linking internal stress and weakens the interfacial bonding between the paint film and the steel plate.

[0119] Due to the lack of an effective end-capping mechanism, Comparative Examples 2 and 4 experienced disordered polymerization reactions within the pipeline after the two components were mixed. This prematurely established molecular weight not only hindered the wetting and spreading of the coating droplets upon contact with the substrate surface, but the high shrinkage stress accompanying the violent reaction directly caused the pull-out adhesion to drop below 8 MPa. The weak interfacial anchoring provided a lateral penetration channel for the corrosive medium, resulting in a corrosion diffusion width exceeding 5 mm in the salt spray test. Comparative Example 5 exposed the fatal hidden danger of excessive use of chemical end-capping agents. Unreacted and non-volatile small molecules remained inside the coating, acting as permanent plasticizers and severely damaging the rigidity and anti-leakage barrier of the epoxy resin skeleton.

[0120] This sponge-like, porous structure not only results in poor mechanical strength but also allows a large number of chloride ions to penetrate deeply, leading to extensive corrosion and peeling of the substrate up to 6.73 mm thick. Comparative Example 3, lacking the high-temperature, high-pressure activation conditions, also faced the problem of incomplete removal of the solvent n-butanol or sealing agent from the paint film, resulting in significantly weaker-than-expected mechanical and physical properties.

[0121] The example group broke through the bottleneck of the mutual constraint between curing speed and film quality in traditional formulations, demonstrating excellent comprehensive protective performance. The pull-out adhesion of Examples 1 to 4 generally exceeded the high industrial standard threshold of 15 MPa, with Example 3 reaching an extremely high level of 17.05 MPa. At the same time, its long-lasting salt spray unidirectional corrosion width was strictly controlled within 1.5 mm for 1500 hours.

[0122] This superior and robust bond stems from the unique physicochemical decoupling that occurs the instant the coating detaches from the pipeline. The adiabatic expansion and vaporization instantly strips away the acetylacetone, not only avoiding network defects caused by small molecule residues, but also causing a dramatic endothermic cooling that freezes the original high-frequency thermal motion within the coating in a very short time.

[0123] Although the rheological structure rapidly reconstructs the anti-sagging structure, the chemical cross-linking reaction of the resin macromolecular segments gains a valuable hysteresis window at low temperatures. This window allows the liquid resin ample time to penetrate deeply into the micro-roughness of the steel plate surface, and during the subsequent gradual curing process driven by ambient moisture-induced ketimine hydrolysis, the inevitable cross-linking shrinkage stress is effectively released through the slow creep of the macromolecular chains. The deep wedging of the stress-defect-free interface and the high-density epoxy curing network together construct a highly robust and long-lasting anti-corrosion barrier, establishing the application advantages of this integrated process in extreme marine engineering environments.

Claims

1. A high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections, characterized in that: Includes the following steps: Bisphenol A type epoxy resin, reactive diluent and mixed solvent are dispersed, and anti-rust pigment and extender filler are added in sequence. After high-speed dispersion and grinding to the specified fineness, component A is obtained. Cashew shell oil-modified phenolic amine was mixed with acetylacetone, and the acetylacetone was used to achieve dynamic hydrogen bond end capping of the phenolic hydroxyl groups. Then, ketoimine and n-butanol were added, and finally polyamide wax micro powder was added to disperse and obtain component B. The components A and B are added to a high-pressure airless sprayer according to the specified ratio and mechanically stirred until homogeneous. The hydraulic pump is set to maintain the working pressure of the fluid in the pipeline at 15.0 to 20.0 MPa. The mixed components A and B form a coating that is rapidly heated to 43-47°C by an inline heater and then sprayed out. The pressure drop inside and outside the nozzle causes adiabatic expansion, which causes the acetylacetone to flash vaporize instantly to unblock the catalytic sites. At the same time, it absorbs latent heat to induce thixotropic network reconstruction, and finally achieves rapid shaping and curing of film on the substrate surface.

2. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, Component A is made from raw materials comprising the following parts by weight: Bisphenol A type epoxy resin: 35-40 parts; 1,4-Butanediol diglycidyl ether: 5-10 parts; Mixed solvent: 5-25 parts; Flake-like mica iron ore: 25-35 parts; Talc powder: 5-7.5 parts; Precipitated barium sulfate: 5-7.5 parts.

3. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, Component B is made from raw materials comprising the following parts by weight: Cashew shell oil modified phenolic amine: 20-25 parts; Acetylacetone: 3-6 parts; Ketoimine: 50-58 parts; Xylene: 9–25 parts; Polyamide wax powder: 2-5 parts.

4. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 2, characterized in that, The steps for obtaining component A specifically include: The bisphenol A epoxy resin, the reactive diluent, and the mixed solvent were added to a dispersion vessel and stirred at 500 rpm until homogeneous. Add the flake-shaped mica iron ore, the talc powder, and the precipitated barium sulfate in sequence, and increase the rotation speed to 1200 to 1500 rpm for high-speed dispersion for 30 to 45 minutes; The material is pumped into a sand mill and ground to a fineness of less than or equal to 50 μm, then filtered and packaged to obtain component A.

5. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 3, characterized in that, The steps for obtaining component B specifically include: The cashew nut shell oil modified phenolic amine was added to a reaction vessel under nitrogen protection. Acetylacetone was added dropwise at a uniform rate under the condition of temperature control at 20 to 25°C for 15 to 20 minutes. After the addition was completed, the mixture was stirred at a constant temperature for 45 to 60 minutes. Add the ketimine and n-butanol, and stir at 300 rpm for 20 minutes; Slowly add the polyamide wax powder, increase the rotation speed to 800 to 1000 rpm and disperse for 20 to 30 minutes, then seal and package to obtain component B.

6. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, The mixed solvent is xylene and n-butanol in a weight ratio of 7:3; The amount of acetylacetone added is such that the molar ratio of acetylacetone to the phenolic hydroxyl groups in the cashew nut shell oil-modified phenolic amine is 0.50 to 0.80:1.0; The mixing ratio of component A and component B is 1.0:0.90 to 0.95, where the total equivalent of epoxy groups is to the total equivalent of active hydrogen.

7. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, In the step of adding component A and component B to the high-pressure airless sprayer according to the ratio and mechanically stirring evenly, the mechanical stirring is carried out at a speed of 200 to 300 rpm for 10 minutes. The mixed paint flows through an inline heater installed 0.4 to 0.6 meters from the spray gun nozzle, and is heated from the initial ambient temperature to 43 to 47°C within 1.5 to 2.5 seconds. Use a standard airless nozzle with an orifice diameter of 0.017 to 0.021 inches and a spray angle of 40 to 60 degrees for spraying, and control the speed of the spray gun to achieve a wet film thickness of 250 to 350 µm for a single spray.

8. The high-efficiency and energy-saving integrated outfitting and painting process for ship hull sections according to claim 1, characterized in that, The specific steps for preparing the cashew nut shell oil-modified phenolic amine include: Cashew phenol and diethylenetriamine are added to a reaction vessel equipped with a reflux condenser and a water separator at a molar ratio of 1.0 to 1.2 to 1.

5. Nitrogen gas is introduced for protection, stirring is started and the temperature is raised to 60 to 70°C. Paraformaldehyde is added in portions at a uniform rate, wherein the molar ratio of paraformaldehyde to cashew phenol is 1.2 to 1.5 to 1.0, and the feeding rate is controlled to maintain the temperature inside the reactor not exceeding 80°C. After the addition of materials is complete, heat the system to 90 to 110°C and maintain the temperature for 2.5 to 3.0 hours. The reactor was changed to vacuum distillation mode, and water and unreacted free amines were removed under a vacuum of -0.08 to -0.09 MPa until no distillate was obtained. The product was then cooled and discharged to obtain cashew shell oil modified phenolic amine.

9. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, The preparation steps of the ketimine specifically include: Ethylenediamine and methyl isobutyl ketone were added to a reflux reactor equipped with a water separator at a molar ratio of 1.0 to 2.2 to 2.

5. The mixture is heated to 110 to 130°C and refluxed. The water generated in the reaction forms an azeotrope with methyl isobutyl ketone. After condensation, the mixture separates into layers in a water separator. The lower layer of water is discharged and the upper layer of methyl isobutyl ketone is refluxed back into the reactor. Continue the reaction for 4 to 6 hours, until no water droplets are produced in the distributor; Excess methyl isobutyl ketone is recovered by vacuum distillation, and after cooling to 40 to 50°C, the product is filtered to obtain methyl isobutyl ketone-derived ketimine.

10. The high-efficiency and energy-saving integrated outfitting and coating process for ship hull sections according to claim 1, characterized in that, In the step of achieving rapid shaping and curing film formation on the substrate surface, the substrate pretreatment and construction environment must meet the following conditions: The substrate is a steel plate and outfitting parts that have undergone sandblasting and rust removal treatment, and the surface roughness of the substrate is controlled to be between 50 and 75 micrometers. The ambient temperature during spraying operations should be controlled between 5 and 15°C. The relative humidity of the environment during spraying operations should be controlled between 50% and 95%.

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