Research And Application Of Solvent-free Internal Drag Reducing Coatings

With the development of long distance buired pipeline in the direction of large diameter,high grade steel and high pressure, the internal drag reducing technology is widely used inpipeline. Within all the technologies, painting internal drag reducing coatings is the mostdirectly economic way. The current solvent internal drag reducing coatings contain solvent,being harmflil to health, polluting environment, even generating hidden danger intransportation security. To solve the problem, a kind of new sol vent-free internal drag reducingcoatings is researched. It has no volatile solvent and the advantage of no harm, no pollutionand security so as to be used widely.This article summairzes the historical development and research status of the internaldrag reducing coatings home and abroad, introducing the drag reducing mechanism of thecoatings on the gas pipe wall, analyzing the factors influence the drag reducing coating quality.According to the standards of the internal coating for steel pipe，a claim is raised for theperformance of solvent-free internal drag reducing coating.In the expeirmental section, epoxy is used as major film-forming resin, a kind of newtype of reactive diluents as lfexibilizer. Through different usage of reactive diluents, it’sstudied on the relation of the reactive diluents and glass transition temperature of coating;through analyzing the structure of coating, the influence on the wearing resistance, compactability and penetration resistance for the padding of different types and graduations isresearched. The effect of different cuirng agents on flexibility is studied，Through the sprayingexpeirments, the dispensing of the solvent-free internal drag reducing coatings andtechnological parameters are ifnally decided.The solvent-free internal drag reducing coating has excellent physical and mechanicalproperties, solids content of more than99%, glossiness of more than75, pull off adhesion ofmore than20MPa, shear strength reaching more than15MPa, completely achieving API RP5L2-2002requests. Compared with the traditional solvent coatings, the solvent-freeproduction has more excellent mechanical properties, signiifcantly reducing the environmentalpollution in production process additionally.