Coating process for pipeline three-layer structural anticorrosive coating

A technology with three-layer structure and coating process, which is applied in the direction of pipeline anticorrosion/rust protection, pipeline protection, and devices for coating liquid on the surface, etc. It can solve the problems of inability to establish microscopic meshing of the surface and fusion of the surface layer, and the combination of FBE and steel pipes , unable to form surface meshing and other problems, to achieve the effect of low preparation cost, reduced material cost, and improved cathodic disbondment resistance

CN102107176BInactive Publication Date: 2013-08-28BC P INC CHINA NAT PETROLEUM CORP +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2013-08-28
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a coating process for a pipeline three-layer structural anticorrosive coating. The coating process comprises the following steps of: 1) performing fusion bonded epoxy (FBE) coating, namely heating a coated substrate, and spraying epoxy powder to the surface of the coated substrate by an electrostatic spraying process to melt an epoxy powder coating and cure the epoxy powder coating into a bottom coating; 2) performing air dielectric (AD) coating, namely coating adhesive powder to the surface of the coated substrate during gelling of the epoxy powder, wherein the surface temperature of the coated substrate is between 170 and 225 DEG C, and the coating thickness is between 80 and 350 mu m; and 3) performing polyolefin coating, namely winding a fabricated polyolefin coil strip on the coated substrate before an adhesive is cooled, wherein the coating thickness is between 0.5 and 4.0mm. By the AD powder coating process, the wound coating is tightly adhered to the substrate, and the anticorrosive coating has high integrity, cathodic disbonding resistance and compactness.
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Description

technical field

[0001] The invention relates to the field of pipeline anticorrosion, in particular to a process for coating a pipeline with a three-layer structure anticorrosion layer. Background technique

[0002] The "three-layer structure" anti-corrosion layer of the steel pipe includes three layers of polyethylene (English abbreviation: 3PE or 3LPE) and three-layer polypropylene (English abbreviation: 3PP or 3LPP), which is currently recognized as the most advanced pipeline anti-corrosion layer. It has a wide range of applications and reliable anti-corrosion performance.

[0003] The three-layer structure specifically refers to the bottom layer as fusion bonded epoxy powder coating (English abbreviation as FBE), and the middle layer as synthetic adhesive (including α-olefin and ethylene copolymer adhesive, graft polymerization modified polyethylene adhesive two types, English Abbreviated as: AD), the outer layer is polyolefin (including polyethylene, English abbreviated...

Examples

Embodiment 1

[0046] A coating process for pipeline three-layer structure anti-corrosion coating, comprising the following steps:

[0047] 1) FBE coating, the curved steel pipe is heated, and epoxy powder is sprayed onto the surface of the curved steel pipe by electrostatic spraying process, so that the epoxy powder coating is melted and solidified into a primer;

[0048] 2) AD coating, during the epoxy powder gelling process, apply the adhesive powder to the surface of the curved steel pipe in step 1), the surface temperature of the curved steel pipe is 170°C, and the coating thickness is 100 μm;

[0049] 3) Polyolefin coating, before the adhesive cools down, wrap the polyolefin PE tape fixing frame heated to 160°C on the curved steel pipe described in step 2) in a lateral winding method, and the tape overlaps by 55% , Heat the surface of the pipe and the PE tape during winding to fuse the PE tape, and the coating thickness is 0.5mm.

Embodiment 2

[0051] A coating process for pipeline three-layer structure anti-corrosion coating, comprising the following steps:

[0052] 1) FBE coating, the steel pipe is heated, and the epoxy powder is sprayed on the surface of the steel pipe by electrostatic spraying process, so that the epoxy powder coating is melted and solidified to form a primer;

[0053] 2) AD coating, before the epoxy powder is gelled, apply the adhesive powder to the surface of the steel pipe in step 1), the surface temperature of the steel pipe is 225°C, and the coating thickness is 350 μm;

[0054] 3) Polyolefin coating. Before the adhesive cools down, the polyolefin PP strip heated to 220°C is wound onto the steel pipe described in step 2) through a rotary winding machine. The strip overlaps by 55%. The surface of the pipe and the PE tape are heated to fuse the PE tape, and the coating thickness is 4.0mm.

Embodiment 3

[0056] A coating process for pipeline three-layer structure anti-corrosion coating, comprising the following steps:

[0057] 1) FBE coating, the substrate to be coated is heated, and epoxy powder is sprayed onto the surface of the substrate to be coated by electrostatic spraying process, so that the epoxy powder coating is melted and solidified into a primer;

[0058] 2) AD coating, before the epoxy powder is gelled, apply the adhesive powder to the surface of the coated substrate in step 1), the surface temperature of the coated substrate is 200°C, and the coating thickness is 200 μm;

[0059] 3) Polyolefin coating, before the adhesive cools down, the AD / PE composite tape of the polyolefin inner layer composite adhesive heated to 200 ° C is wound onto the coated substrate described in step 2) through a rotary winding machine. On the material, the strip overlaps by 55%. When winding, the pipe surface and the PE strip are heated to fuse the PE strip. The coating thickness is 2....