Pipeline anticorrosion refers pipeline using transport pipeline cited by the use of the environment and transport medium shadow pipeline corrosion chemical or electrochemical reaction. In order to effectively prevent or control pipeline corrosion, scientists are seeking a new, higher, more effective method. New pipeline anti-corrosion technology continues to emerge, can be roughly divided into the following types:
Main types of anti-corrosion coatings
1, grease paint - the atmospheric corrosion undemanding environment.
Grease coating is a dry oil for a class of the main film coatings. Which is characterized by ease of production, good brushability, good wettability on the object surface, inexpensive, flexible film; but the slow drying of the film, the film is soft, poor mechanical properties, acid resistance, water resistance and an organic solvent is poor. Drying oils often in conjunction with anti-rust pigment composition of the anti-rust paint used in the corrosion insensitive atmospheric environment.
2, the country paint
The lacquer also known as lacquer, paint, is one of our specialties. Lacquer from the sumac grows to cut bark flow out of a milky viscous liquid, muslin filter to remove impurities that. After it is coated on the surface of the object, the color rapidly from white to red, from red to purple, a long time can be turned into a hard, shiny black film. Urushiol is the main component of the lacquer, containing up to 30% to 70%. Generally speaking, the higher the content of urushiol lacquer better quality. Country strong paint adhesion, tough film, good gloss, it is resistant to soil corrosion than water resistance, oil. The disadvantage is toxic, easy to make skin allergies. In addition, it is resistant to strong oxidant, the alkali resistance is poor. Now many modified lacquer paint, to varying degrees, to overcome these shortcomings.
3, a phenol resin coating
Alcohol-soluble phenol resin, a modified phenolic resin, phenolic resin or the like. Alcohol-soluble phenolic resin coating corrosion resistance is better, the inconvenience, but the construction is not very good flexibility, adhesion, has limited application. Therefore often requires the modified phenolic resin. Such as rosin-modified phenolic resin and tung oil refining, adding various pigments, can be obtained by grinding a variety of enamel, tough film, inexpensive, and widely used for furniture, doors and windows, painting. Pure phenolic resin coating adhesion, water resistance to heat, corrosion resistance, good weatherability.
4, epoxy coatings
Good adhesion of epoxy coatings have excellent adhesion to metal, concrete, wood, glass, etc.; alkali, oil and water, excellent electrical insulation properties. However, the aging resistance. Epoxy anti-corrosion coating is usually composed of two components of an epoxy resin and a curing agent. The nature of the curing agent also affects the performance of the film. The commonly used curing agents are: ① fatty amines and their modified compounds. Features can be cured at normal temperature, the greater toxicity of unmodified aliphatic amines. ② aromatic amines and its modified product. The characteristics of the reaction is slow, and often have to heat curing virulent. (3) a polyamide resin. Characterized by good weather resistance, less toxic, good elasticity, corrosion resistance can be somewhat less. ④ phenolic resins, urea resins, and other synthetic resin. These resins and epoxy resins and crosslinked film after baking at high temperature, the film has outstanding corrosion resistance, and has good mechanical properties and decorative. Epoxy ester resin paint is an epoxy ester resin as a film-forming substance a single component coating systems. The epoxy ester resin from an epoxy resin, and vegetable oil fatty acid esterified collectively made. The paint and general epoxy coatings compared to lower-cost, poor alkali resistance. Commonly used for a variety of metal primer and chemical plants outdoor equipment anti-corrosion paint.
5, polyurethane coatings
A polyurethane resin for anti-corrosion coatings often contain two components: an isocyanate group-NCO and hydroxy. When using two-component mixing reaction curing generate polyurethane (PU).
Features: ① physical and mechanical properties of polyurethane coatings. Film hard, flexible, bright, plump, wear-resistant, strong adhesion. ② corrosion resistance is excellent. Oil, acids, chemicals and industrial emissions. The alkali resistance is slightly lower than the epoxy coatings. ③ aging resistance than epoxy paint. Commonly used as a topcoat, but also can be used as a primer. The ④ polyurethane resin and a variety of resin miscible, recipe can be adjusted within a wide range of use in order to meet a variety of requirements. ⑤ can be cured at room temperature or heat curing, can be cured at low temperatures (0 ℃). ⑥ polyisocyanate component poor storage stability, must be isolated from moisture to avoid jelly. The high price of polyurethane coatings, but long life.
6, polyethylene, polypropylene resin coating
Anti-corrosion coatings of polyethylene resin is a monomer made of resin for the coating of the film-forming substance. The polyethylene coating mass production. Strong sealing polyethylene pipe anti-corrosion, high mechanical strength, waterproof and strong, stable quality, convenient construction, applicability, and does not pollute the environment. PE with low water absorption (less than 0.01%), along with ethylene, high strength the low PE absorbent and good hot melt softness. High corrosion reliability, the disadvantage is: compared with other mending material costs and high costs. Rich source of raw materials in the paint, have been widely used in corrosive.
7, a furan resin coating
Furan resin coatings resistant to a variety of non-oxidizing mineral acid, an electrolyte solution and various organic solvents, and alkali resistance is also very prominent, but bad Antioxidant. The furan resin series of anti-corrosion coatings, including furfuryl alcohol resin paints, of furfural acetone formaldehyde resin coatings and modified furan resin paint.
8, asphalt coating
Asphalt is one of the important anti-corrosion coatings. Especially in the coal tar pitch, coal tar pitch coatings cheap, has the following advantages: ① water, immersed in water for 10 years and its water absorption of only 0.1% to 0.2%; ② resistant to some chemical erosion of media; ③ on the steel surface is still not fully rust the good wettability; ④ solid content to be thick-film; ⑤ inexpensive. The disadvantage is that the winter crisp, summer heat, feeble, and after exposure to the some ingredients volatile escape causes the paint film cracking. These drawbacks can be improved by adding some other resin. Such as adding chlorinated rubber asphalt paint dry, to improve the shortcomings of the the winter crisp summer soft; adding epoxy asphalt coating of epoxy resin obtained advantages both asphalt coating and epoxy coatings, anti-corrosion very satisfied with the results. The asphalt coating occasions in the container bottom, the bottom of the boat, dock gate, the cofferdam use good anti-corrosion effect.
9, heavy anti-corrosion coatings
Heavy anti-corrosion coating is relatively general anti-corrosion coatings. It is under severe corrosion conditions than the general corrosion coatings, anti-corrosion effect several times more than the anti-corrosion coatings. Which is characterized by resistance strong corrosive media outstanding performance, durability, and service life of more than a few years. Mainly used for marine structures and chemical equipment, storage tanks and pipelines.