Preparation method and application of pipeline anticorrosion and pressure-resistant paint coating

Abstract

The application discloses a kind of preparation method and application of pipeline anticorrosion pressure-resistant paint, belong to the technical field of coating preparation.The coating is with modified epoxy resin as base material, compound anticorrosion filler, pressure-resistant reinforcing agent and various functional additives of specific proportion are compounded, and is prepared by step-by-step premixing, high-speed dispersion, grinding, curing and blending.The compound anticorrosion filler is compounded by mica powder, graphite powder, zinc powder and nano titanium dioxide according to the ratio of 3:2:2:1, the pressure-resistant reinforcing agent is compounded by glass fiber microbead and carbon fiber powder according to the ratio of 1:1, and the solvent is a mixed system of butyl acetate and anhydrous ethanol.The preparation process includes base material premixing, additive dispersion, filler mixing and grinding and curing and blending steps, and the obtained coating can be applied to the inner and outer walls of pipeline by spraying, brushing or rolling.The coating has excellent anticorrosion performance and mechanical pressure resistance, the coating adhesion is grade 1, the compressive strength is greater than or equal to 30 MPa, the salt spray resistance is greater than or equal to 5000 h, and the coating does not break after 180 days of acid and alkali immersion, has the characteristics of dense film formation, not easy to crack and fall off, convenient construction, green environmental protection, etc., and is suitable for long-term protection of pipelines under complex working conditions such as oil and gas transportation, municipal water supply and drainage, chemical sewage disposal, etc.

Description

I. Technical Field

[0001] This invention belongs to the field of coating preparation technology, and is particularly suitable for long-term protection of metal and composite pipelines in buried, pressurized, and corrosive environments. II. Background Technology

[0002] As the core transport carrier in fields such as petrochemicals, municipal water supply and drainage, oil and gas transportation, and industrial sewage discharge, pipelines are subjected to complex working conditions such as soil corrosion, media erosion, external pressure, and geological subsidence for a long time. They are prone to problems such as pipe wall corrosion, coating peeling, and structural damage, which not only significantly shorten the service life of pipelines, but also easily cause safety accidents such as leaks and explosions, resulting in economic losses and environmental hazards.

[0003] Existing pipeline anti-corrosion coatings generally suffer from drawbacks such as insufficient pressure resistance, poor corrosion durability, weak adhesion, and limited resistance to specific media corrosion. On the one hand, ordinary anti-corrosion coatings are prone to cracking, delamination, and peeling under long-term external soil pressure and internal pipeline media pressure, thus losing their protective effect. On the other hand, traditional coatings are difficult to adapt to multiple corrosive environments such as acid and alkali corrosion, salt spray erosion, and microbial degradation, resulting in short-term corrosion protection and frequent repairs and maintenance. In addition, some high-corrosion-resistance coatings suffer from complex preparation processes, difficult construction, and poor environmental performance, failing to meet the application requirements of large-scale pipeline projects.

[0004] Current technologies mostly focus on single-function corrosion protection or single-function reinforcement, making it difficult to achieve a synergistic balance among corrosion resistance, compressive strength, adhesion, and workability. Therefore, developing a pipeline-specific paint or coating that combines excellent corrosion resistance, mechanical compressive strength, strong adhesion, convenient construction, and environmental friendliness, optimizing its preparation process, and expanding its application in pipelines under complex working conditions has become an urgent technical problem to be solved in this field. III. Summary of the Invention

[0005] To address the shortcomings of existing pipeline anti-corrosion coatings, such as insufficient pressure resistance, poor corrosion resistance and durability, easy cracking and peeling, and low applicability in construction, this invention aims to provide a method for preparing a pipeline anti-corrosion and pressure-resistant paint coating. Through the synergistic effect of modified epoxy resin, composite anti-corrosion filler, and pressure-strengthening agent in a specific ratio, the coating is endowed with significantly improved anti-corrosion, pressure resistance, impact resistance, and aging resistance. Simultaneously, this invention provides an application method for the coating, achieving efficient and long-term pipeline protection, suitable for pipeline coating under various complex working conditions. Technical solution

[0006] 0006 By weight, the pipeline anti-corrosion and pressure-resistant paint coating comprises the following components: 40-60 parts modified epoxy resin, 15-25 parts composite anti-corrosion filler, 8-15 parts compressive strength enhancer, 3-6 parts film-forming aid, 1-3 parts dispersant, 0.5-2 parts leveling agent, 0.3-1.5 parts defoamer, 5-10 parts curing agent, and 10-20 parts environmentally friendly solvent.

[0007] 1. The modified epoxy resin is an epoxy-modified silicone resin, which combines high adhesion, corrosion resistance and mechanical toughness, and significantly improves the density of the coating.

[0008] 2. The composite anti-corrosion filler is composed of mica powder, graphite powder, zinc powder, and nano titanium dioxide mixed in a mass ratio of 3:2:2:1, forming a multi-layer physical shielding and electrochemical protection synergistic anti-corrosion system.

[0009] 3. The compressive strength enhancer is a mixture of glass fiber microspheres and carbon fiber powder in a 1:1 mass ratio, which can form a spatial skeleton structure inside the coating, greatly improving compressive strength and impact resistance.

[0010] 4. Preferably, the film-forming aid is 1-dodecyl alcohol ester; the dispersant is polyacrylate dispersant; the leveling agent is polydimethylsiloxane; the defoamer is silicone defoamer; and the curing agent is modified alicyclic amine curing agent.

[0011] 5. Preferably, the environmentally friendly solvent is a mixture of butyl acetate and anhydrous ethanol in a mass ratio of 2:1, which has a moderate evaporation rate, low toxicity, and is suitable for on-site construction.

[0012] (II) Preparation steps 1. Base material premixing: Add modified epoxy resin and environmentally friendly solvent to the reactor, stir at 300-500 r / min for 15-25 min, heat to 40-50℃ until the resin is completely dissolved to form a uniform base material liquid.

[0013] 2. Additive dispersion: Add dispersant, leveling agent and defoamer to the base liquid in sequence, keep the speed constant and continue stirring for 10-15 minutes to ensure that the additives are fully and evenly dispersed.

[0014] 3. Filler mixing: Slowly add the composite anti-corrosion filler and compressive strengthening agent into the reactor, increase the stirring speed to 800-1200 r / min, disperse at high speed for 20-30 min, and grind with a sand mill until the slurry fineness is ≤20μm to obtain the mixed slurry.

[0015] 4. Curing and preparation: Cool the mixed slurry to 25-30℃, add curing agent and film-forming aid, stir at 400-600r / min for 15-20min, after thorough mixing, let stand for curing for 30-45min, filter to remove impurities, and you will get the pipeline anti-corrosion and pressure-resistant paint coating.

[0016] III. Preparation method and application of a pipeline anti-corrosion and pressure-resistant paint coating The anti-corrosion and pressure-resistant paint coating for pipelines prepared by this invention is suitable for the protection of the inner and outer walls of metal pipelines and composite pipelines. It can be widely used in oil and gas pipelines, municipal buried water supply and drainage pipelines, chemical sewage pipelines, industrial circulation pipelines, and other scenarios. The specific application steps are as follows: 1. Pipe surface treatment: Use sandblasting, shot blasting or mechanical grinding to remove rust, oil, dust and oxide scale from the pipe surface, so that the surface roughness reaches Ra25-40μm and the surface is kept dry and clean.

[0017] 2. Coating application: Stir the prepared anti-corrosion and pressure-resistant paint evenly, and apply it by spraying, brushing or rolling. The ambient temperature for coating should be controlled between 15-35℃ and the relative humidity ≤85%.

[0018] 3. Coating curing and molding: After the first coating is completed, let it stand at room temperature for 2-4 hours to cure before applying the second coating. The total coating thickness should be controlled at 80-120μm. After coating, let it cure naturally at room temperature for 24-48 hours, or bake at 60-80℃ for 1-2 hours.

[0019] 4. Finished product inspection and curing: After curing, inspect the coating adhesion, thickness and integrity. If there are no defects such as missed coating, cracks or bubbles, it can be put into use after 7 days of static curing. Beneficial effects

[0020] 1. Excellent synergistic performance: This invention uses a specific ratio of resin, filler and reinforcing agent to form a coating with a compressive strength ≥30MPa, salt spray resistance ≥5000h, and acid and alkali immersion for 180 days without damage, solving the problems of traditional coatings being prone to cracking and corrosion.

[0021] 2. Strong adhesion and durability: The coating has a Grade 1 adhesion to metal and composite substrates, forming a dense film without pinholes. It can withstand soil pressure and media erosion for a long time, and its anti-corrosion life can reach more than 20 years.

[0022] 3. Green and convenient process: The preparation conditions are mild, no complicated equipment is required, the environmentally friendly solvents are low in toxicity, and it is suitable for industrial production and on-site construction.

[0023] 4. Wide range of applications: It can be adapted to various complex working conditions such as buried, pressurized, and multi-corrosion pipelines, which greatly reduces maintenance costs.

Claims

1. The preparation method according to claim 1, characterized in that, The modified epoxy resin is an epoxy-modified silicone resin.

2. The preparation method according to claim 1, characterized in that, The composite anti-corrosion filler is composed of mica powder, graphite powder, zinc powder, and nano titanium dioxide mixed in a mass ratio of 3:2:2:

1.

3. The preparation method according to claim 1, characterized in that, The compressive strength enhancer is composed of glass fiber microspheres and carbon fiber powder in a mass ratio of 1:

1.

4. The preparation method according to claim 1, characterized in that, The film-forming aid is 12-ol ester, the dispersant is polyacrylate dispersant, the leveling agent is polydimethylsiloxane, the defoamer is silicone defoamer, and the curing agent is modified alicyclic amine curing agent.

5. The preparation method according to claim 1, characterized in that, The environmentally friendly solvent is a mixture of butyl acetate and anhydrous ethanol in a mass ratio of 2:

1.

6. The application of a pipeline anti-corrosion and pressure-resistant paint coating prepared according to any one of claims 1-6, characterized in that, The coating is used for the protection of the inner and outer walls of metal or composite pipes. The specific application steps are as follows: (1) Pipe surface treatment: Use sandblasting, shot blasting or mechanical grinding to remove rust, oil, oxide scale and impurities from the pipe surface, so that the surface roughness reaches Ra25-40 μm and the surface is kept dry and clean. (2) Coating application: Stir the coating evenly and apply it by spraying, brushing or rolling. The ambient temperature should be controlled between 15-35℃ and the relative humidity ≤85%. (3) Coating curing and molding: After the first coating is left to cure for 2-4 hours, the second coating is applied. The total coating thickness is controlled at 80-120 μm. After coating, it is naturally cured at room temperature for 24-48 hours, or baked at 60-80℃ for 1-2 hours. (4) Finished product inspection and curing: After curing, check the integrity of the coating, whether there are any omissions, bubbles, or cracks. After 7 days of static curing, it can be put into use.

7. The application according to claim 7, characterized in that, The pipelines include oil and gas transmission pipelines, municipal buried water supply and drainage pipelines, chemical sewage pipelines, and industrial circulation pipelines.

8. The application according to claim 7, characterized in that, The coating formed by the coating achieves Grade 1 adhesion, compressive strength ≥30 MPa, withstands immersion in 5% hydrochloric acid and 5% sodium hydroxide solution for 180 days without damage, and withstands neutral salt spray corrosion ≥5000 hours.