Research on the development and performance of flexible ceramic heavy anti-corrosion coatings

In the petroleum and petrochemical industry, oil and gas collection pipelines, injection wells, crude oil separators, heat exchangers and other equipment internal wall corrosion is very serious, in addition to simple high temperature, media corrosion damage, but also often accompanied by friction between equipment, liquid transport media flushing and other mechanical damage. Compared with the corrosive effect of liquid media, crude oil and oil field sewage and other media damage to pipeline equipment is the most serious, its composition is complex, dissolved complex salts and gases, in the process of oil extraction also carried a lot of sediment particles, etc. , in the process of transport on the pipe wall corrosion, flushing wear capacity, more effective anti-corrosion measures are painting corrosion-resistant and chemical resistance and other excellent performance of flexible ceramic anti-corrosion coating.flexible ceramic coating is epoxy resin as a film material, ceramic powder as a wear-resistant filler temperature-curable two-component coating, the coating has both ceramic rigidity and resin toughness . In recent years, with the increasing demand for corrosion prevention in related fields, some international companies have introduced the concept and related products of heavy anti-corrosion wear ceramic coatings, Freecom of the United States designed and configured SEK 54 (CK-54) advanced ceramic coating materials, Korea Jingxing Industrial Co., Ltd. developed and produced Atometal metal ceramic coatings and Germany's Ceramic Polymer Gmbh company developed CP ceramic paint has been widely used in many areas of petroleum and petrochemical.currently domestic coatings companies in the field of flexible ceramic heavy anti-corrosion coatings have not yet excellent performance products. Based on the above background, in view of these special corrosion environment, this paper has developed a high wear-resistant flexible ceramic heavy anti-corrosion coating, with abrasive resistance, high temperature resistance, chemical resistance and other comprehensive properties, to meet the offshore platform and offshore oil and gas production and other equipment and facilities in the special corrosion environment such as pipelines, crude oil separators, open discharge tanks, elbows and other needs of erosion-resistant erosion, temperature resistance and chemical corrosion-resistant media needs.1Experimental Part 1.1
Raw Materials Phenol Etonal Epoxy Resin, Bisphenol F Epoxy Resin: South Asia Corporation of Taiwan; Titanium: redstone type; Dispersant: Bick Company; Desiccant: BASF Company; Silicon Carbide: Yamada Grinding Materials Co., Ltd.; Alumina: Shandong Non-Chi Star Aluminum Co., Ltd.; Solvents are commercially available industrial products; Thinners: Homemade.1.2
Formula design and painting process according to table 1 formula in turn add phenolic epoxy resin, bisphenol F epoxy resin, mixed solvents, dispersants and desmoulators stirred well, and then added tentacles, pigments and fillers, stirred evenly after grinding, until the specified fineness, adjust the viscosity, to obtain flexible ceramic coating A part.1 Flexible ceramic coating base formula
Note: (1) a total of 100% ;(2) by the A-part resin dosing and solid content calculated.1.3
model preparationfor adhesion (scratching method), flexibility, impact resistance testing of the model are prepared in accordance with the requirements of the relevant chemical industry standards, coating film using air spray method, its film thickness is in (20±3) m; pull-out method adhesion, salt-resistant fog, acid-resistant, alkali-resistant test using 3mm steel plate, its preparation process is as follows: model surface de-oil blasting treatment, the back of the model spray epoxy thick slurry-type coating protection treatment, air spray flexible ceramic coating, film thickness of 250 m.1.4
test methodtest method for flexible ceramic coatings can be found in Table 2.2 Flexible ceramic coating performance test method 2results and discussion of 2.1
the basic formula of flexible ceramic coatings 2.1.1
substyl resin selection The flexible ceramic heavy anti-corrosion coating is mainly used in erosion environments such as flushing wear, chemical media and high temperatures, while traditional Bisphenol A epoxy resin-polyamide curing agents are not resistant to wear, temperature, solvents and chemicals due to their low cross-linking density. Moreover, the glass temperature of the system is about 50 degrees C, and when the media temperature is higher than the glassing temperature, the permeability of the corrosive medium to the coating is greatly improved, so its media resistance temperature can only be lower than its glassing temperature. In order to solve the deficiency of ordinary epoxy resin on the corrosion environment corrosion resistance, the cross-link density of traditional resin system and the glass temperature can be improved, but also to ensure that the resin and curing agent can be fully cured at room temperature.phenolic epoxy resin official energy is large, if the same curing agent is used, phenolic epoxy resin eventually cured into a film cross-link density is larger, glass temperature is also higher, so this study chose phenolic epoxy resin as the main resin of flexible ceramic coatings. However, too much cross-link density will make the coating too rigid, mechanical performance is poor, and the glass temperature is too high will make the curing reaction incomplete, affecting the chemical resistance of the coating. Bisphenol F epoxy resin according to the molecular structure also belongs to the phenolic epoxy resin, but its official energy is relatively low, the viscosity is low, the system glass temperature is also low. Therefore, the study selected phenolic epoxy resin mixed with bisphenol F resin, in the control of A component solid content and other component ratio unchanged, the choice of lipocycline as a curing agent, add a certain amount of plasticizer, study the different resin ratio to paint viscosity, physical mechanical properties, wear resistance, acid resistance and the effect of hot water resistance, the results can be seen in Table 3.TableTable 3 different resin ratio on the performance of ceramic coatings From Table 3, it can be seen that the content of phenolic epoxy resin is too high, the physical mechanical properties of the coating and acid and high temperature water resistance performance is poor, which is due to the coating cross-link density is too high so that the coating film is too rigid and the degree of coating curing is low; Taking into account the various properties of the coating, choose m (phenolic epoxy) m (Bisphenol F) as a flexible ceramic coating resin system.2.1.2 choice of
curing agent Although the traditional polyamide curing agent is excellent in preservative and water resistance, its curing system has poor chemical resistance and wear resistance. The aromatic amine curing agent with better chemical resistance can not be fully cured with phenolic epoxy resin at room temperature and its toxicity is greater. The fatamine curing agent has a high degree of curing with phenolic epoxy resin at room temperature, but the chemical resistance of the curing substance is not as good as that of the lipocyclic amine curing agent. Although the lipocycline curing agent and phenolic epoxy resin fully react with the higher glassing temperature, but because the resin contains a lower glass temperature of bisphenol F resin. Therefore, the study selected lipocamine, which can be fully cured at room temperature, while the curing material is wear-resistant and chemically resistant, is superior as a curing agent. There are many types of lipocamine curing agents, choose 2 different structures of lipocamine curing agentSA and B (molecular structure as shown in Figure 1) for performance comparison, according to the basic formula, wherein the resin is m (phenolic epoxy): m (Bisphenol F) - 7:3, the face ratio is 3.5:1, ceramic powder selection aluminum carbide mica powder compounding, the results are shown in Table 4. Table 4 different curing agents on the performance of ceramic coatings From Table 4, it can be seen that curing agent A performance is better than curing agent B although the official energy of curing agent B is greater than curing agent A, but because there is an amino group located in the middle of the molecule, more difficult to react with the epoxy group in the resin, resulting in insufficient curing degree, so the paint chemical resistance caused adverse effects. In this study, the curing agent A (isofolone damine) was selected as a flexible ceramic coating curing agent, and its molecular structure contained both the structure of lipocycline and the structure of fatamine, the reaction activity was higher, the reaction speed was faster, the curing agent could be fully cured at room temperature and the use of curing promoter could be reduced. Figure 1 2 curing agent molecular structure diagram At the same time, for the high cross-link density system of lipocycline curing, the use of plasticizer is very important, it can reduce the glass temperature of the system, improve the curing degree, increase the flexibility of the coating, generally used to cure liquid epoxy resin in the fat ring amine curing agent contains a certain amount of plasticizer. Phenyl methanol, as one of the most commonly used plasticizers, is widely used in epoxy-amine curing systems. However, its excessive use can have a significant negative impact on the chemical resistance of the system. In this study, it was determined by test that the dosing amount was 7.5% of the resin dosing amount. 2.1.3
Determination of the pigment base ratio When the pigment PVC is small, the pigment filler is not filled with enough resin, the system is less dense, so corrosion-resistant media permeability is reduced, acid resistance, chemical resistance performance is reduced, and coating costs rise. If the pigment PVC is too high, greater than its CPVC, the pigment can not be completely covered by the resin, part of the pigment particles free in the resin space structure gap, resulting in the combination between the coating and substrate affected, other resistance and physical mechanical performance will also be reduced. To m (phenolic epoxy) : m (bisphenol F) s 7:3 as a flexible ceramic coating substation resin, the selection of isofrondiamine as a curing agent, to maintain the other parts content unchanged, to investigate the effect of different face ratio on the performance of ceramic coatings, the results as shown in Table 5. Table 5 pigment ratio on the performance of ceramic coatings flexible ceramic coatings due to its wear resistance, chemical resistance performance requirements, to ensure that no more than the pigment CPVC premise, as far as possible to improve the density of pigments. From the experimental results, it can be seen that the ceramic coating has the best performance when the pigment ratio is 3.5:1, indicating that the volume concentration of the pigment at the time of the matching reaches or approaches its critical volume concentration, therefore, the ceramic paint pigment ratio is selected 3.5:1. 2.1.4
Ceramic Powder Selection High wear resistance is an important energy indicator for flexible ceramic coatings, in addition to the selection of suitable resins and curing agents to increase the cross-link density of the system, the selection of different types and different particle sizes of wear-resistant ceramic powder with wood is also an effective way to increase wear resistance. At the same time, flexible ceramic coatings for high-solid coatings, need to choose a small amount of oil-absorbing fillers to reduce the viscosity of the coating. Common ceramic powders include zirconium oxide powder, alumina powder, silicon oxide powder, boron nitride powder, silicon carbide powder and morashi powder. The experimental results show that choosing a single variety of ceramic powder as a filler will reduce the comprehensive performance of the coating. In this study, ceramic powder was selected for a complex use of alumina, silicon carbide and mica powder, and the optimal ratio was determined to be 4:4:2 through test testing. at the same time, the selection of ceramic powders of different particle sizes increases the tightness of wear particles and the hardness of the coating, thus increasing the wear resistance, water resistance and chemical resistance of the coating. Keep the content and proportion of other powders unchanged, choose 500, 1000, 1500 eyes of silicon carbide powder mixed use, and pure 1000 eyes of silicon carbide powder formula performance comparison, the results can be seen in Table 6. Table 6 different silicon carbide indicators on the performance of ceramic coatings From Table 6, it can be seen that the use of different numbers of ceramic powder mixed use, can significantly increase the wear resistance and acid and water resistance of ceramic coatings. Therefore, the study selected different numbers of silicon carbide and combined with alumina powder and mica powder. 2.2
Flexible ceramic coating performance evaluation to m (phenolic epoxy) m (bisphenol F) - 7:3 as the base resin, lipo cyclamine as a curing agent, add a certain amount of plasticizer benzo alcohol and choose alumina, silicon carbide and mica powder as ceramic powder, the face ratio of 3.5:1 flexible ceramic coating. Select a common imported ceramic coating on the market and flexible ceramic coatings for comparison, according to the 1.4 section performance test method to test its performance, the results can be seen in Table 7. Table 7 Flexible ceramic coatings and imported ceramic coatings comprehensive performance comparison From Table 7, it can be seen that the research prepared flexible ceramic coatings chemical resistance, high temperature resistance, corrosion resistance, performance, aesthetic performance and foreign imported ceramic coatings equivalent, wear resistance slightly better than imported ceramic coatings. 3 Conclusion (1) to m (phenolic epoxy) m (BPAF) - 7:3 as the base material, to isofolone damine as a curing agent, the face-based ratio of 3.5:1, aluminum oxide, silicon carbide, mica powder as ceramic powder, the development of flexible ceramic heavy anti-corrosion paint. (2) developed flexible ceramic coatings with good physical and mechanical properties, as well as excellent wear resistance, chemical resistance and temperature resistance, and imported ceramic coatings performance. The ceramic coating can be used in oil and gas collection pipelines, injection wells, crude oil separators, heat exchangers, elbows and other parts of the need for erosion resistance, temperature resistance and corrosion resistance to chemical media. Liu Baocheng, Lian Bingjie, Cao Bihui, Fang Jianjun, Xu Ke, Ma Shengjun (CNOOC Changzhou Coatings and Chemical Research Institute Co., Ltd., Changzhou, Jiangsu 213016) Source: 2018 Paint Industry Issue 9