Solvent free epoxy coating anti-corrosion steel pipe

Overview of solvent-free epoxy coatings

Solvent free epoxy coating is a two-component reaction cured anti-corrosion coating made by high-speed dispersion and grinding of low viscosity epoxy resin, pigments, additives, etc., and using low viscosity modified amine as a curing agent. The prominent advantage of using this coating is that it can reduce the air pollution caused by the volatilization of organic solvents. Moreover, it has excellent physical and mechanical properties, chemical resistance, and anti-corrosion performance. For example, it has excellent adhesion to the substrate and good wet adhesion; The coating formed after cross-linking and curing is hard, flexible, wear-resistant, scratch resistant, and impact resistant; It can effectively resist corrosive media such as water and oxygen from penetrating through the coating and corroding steel.

Characteristics of solvent-free epoxy coating anti-corrosion steel pipes

advantage

Good environmental friendliness: As solvent-free epoxy coatings do not contain volatile organic solvents, they can reduce environmental pollution and meet current environmental requirements. China is paying more and more attention to environmental protection, strictly limiting the volatile organic compounds (VOCs) in coatings, and solvent-free epoxy coatings are in line with this development direction.

Excellent anti-corrosion performance: The highly cross-linked solvent-free epoxy anti-corrosion coating can withstand long-term immersion in seawater, moderate acid, alkali, salt, various oils, fatty hydrocarbons and other chemicals, and has a dense film formation, which can effectively block the corrosion of steel by corrosive media.

Good physical properties: The coating has strong adhesion to the substrate, especially excellent wet adhesion, which enhances the durability of the coating in corrosive environments of liquid media; The coating is hard, flexible, wear-resistant, scratch resistant, and impact resistant; During the reaction curing process, the shrinkage rate is extremely low, the one-time film formation is thick, the edge coverage is good, the internal stress is small, and it is not easy to produce cracks.

High economy: Although the unit price of solvent-free epoxy coatings is slightly higher than that of solvent based epoxy coatings, the solid content is nearly 100%. When reaching the same coating thickness, the required amount of coating is less than that of solvent based coatings; And one layer can reach a high film thickness, which can reduce the number of construction layers and lower the cost of coating construction.

Construction advantages: It is convenient and fast for pipeline joint repair construction, and can be used for on-site construction and repair, avoiding the health hazards and groundwater pollution caused by coal tar enamel coating and epoxy coal tar asphalt anti-corrosion coating during construction.

disadvantage

Strict requirements are imposed on substrate treatment, environmental temperature, and applicable period during construction. For example, during low temperatures in winter, solvent-free epoxy coatings are inconvenient for pipeline joint repair construction.

Applicable scenarios

Petrochemical industry: In China's petrochemical industry, a large number of storage tanks and pipelines constructed from crude oil transportation, storage and transfer, pipeline transportation, refining production to finished oil storage can use solvent-free epoxy coating anti-corrosion steel pipes, such as the outer wall and inner wall of buried pipelines. For example, solvent-free epoxy coating is used on the inner wall of the 175KL brine pipeline in the Huai'an brine procurement and transportation project of the Lianyungang Alkali Factory raw material adjustment project.

Other industries: Suitable for underground water supply and drainage, underground grouting, positive and negative pressure ventilation, gas drainage, fire sprinkler and other pipeline networks in coal mines, as well as process water waste and return water transportation pipelines in thermal power plants.

Relevant standards

The enterprise standard QCNPC-GD-0291-2006 of China Petroleum and Natural Gas Pipeline Bureau specifies various requirements for solvent-free liquid epoxy anti-corrosion coatings for the outer walls of buried steel pipelines used for transporting crude oil, refined oil, natural gas, and water, including coating performance, coating technical indicators, surface treatment, and construction quality control requirements. This standard divides solvent-free epoxy anti-corrosion coatings into ordinary and reinforced grades, with ordinary grade dry film thickness ≥ 400 μ m and reinforced grade ≥ 550 μ m.

The Chinese petroleum and natural gas industry standard SY/T0457-2000 specifies the technical indicators, coating performance, coating process, quality inspection, coating repair, on-site joint patching, etc. of solvent-free liquid epoxy coatings applied for anti-corrosion of steel pipes.