Solvent-free epoxy prime coat for coating welded joints of pipelines and preparation method thereof

Abstract

The invention discloses a solvent-free epoxy prime coat for coating welded joints of pipelines and a preparation method thereof, and belongs to the technical field of pipeline paint. The solvent-free epoxy prime coat comprises the following components in proportion by weight: a component A and a component B, wherein the component A comprises 40-50 parts of JEh-023 type epoxy resin with high temperature resistance, 4-7 parts of resorcinol epoxy resin whose epoxy value is 0.74-0.83mol / 100g, 0.2-0.5 parts of an acrylic resin antifoaming agent whose solid content is 100%, 44-55 parts of feldspar powder, and 0.1-0.3 parts of a pigment; and the component B comprises 63-75 parts of 1,3-bis(aminomethyl)benzene, 20-30 parts of isophorone diamine, and 3-7 parts of resorcinol epoxy resin whose epoxy value is 0.74-0.83mol / 100g; the weight proportion between the component A and the component B is 100:10-15. After the solvent-free epoxy prime coat is immersed in hot water at 95 DEC for 120 days, peel strength between the prime coat and a polypropylene heat-shrinkable tape is 50N / cm or above; after the prime coat is immersed in hot water at 95 DEG C for 28 days, cathodic disbonding distance of the prime coat is 10mm or below; after the prime coat is immersed in hot water at 95 DEG C for 30 days, pull off adhesion strength between the prime coat and the pipeline is 8MPa or above; and requirements for coating welded joints of buried steel pipelines whose highest operating temperature is 110 DEG C are satisfied.

Description

technical field [0001] The invention relates to the technical field of pipeline coatings, in particular to a solvent-free epoxy primer for jointing of pipelines which can be stably bonded to a polypropylene heat shrinkable tape and a preparation method thereof. Background technique [0002] Oil and gas pipelines will corrode during long-term service, so an anti-corrosion layer is usually installed on the outer surface of oil and gas pipelines. However, in order to facilitate welding, no anti-corrosion layer is installed at the joints at both ends of the oil and gas pipeline. In order to ensure the overall anti-corrosion effect of the oil and gas pipeline, it is necessary to carry out anti-corrosion treatment at the joint of the oil and gas pipeline. At present, the jointing structure combined with polypropylene heat shrinkable tape and epoxy primer coating is used for jointing treatment on the outer anti-corrosion layer of buried steel pipelines with a maximum operating temp...

AI Technical Summary

Problems solved by technology

[0004] In the process of realizing the present invention, the inventors have found that the prior art has at least the following problems: the existing epoxy primers for oil and gas pipeline joints are only suitable for oil and gas pipelines with a maximum operating temperature lower than 80°C. The bonding strength between oxygen primer and polypropylene heat shrink tape will be reduced in high temperature environment, and the resistance to cathodic disbondment is poor

Therefore, the existing epoxy primer cannot meet the requirements of the buried steel pipeline joints with a maximum operating temperature of 110°C

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