KR101583657B1 - A method for coating of pipes and joints for preventing corrosion - Google Patents

Abstract

The present invention relates to a corrosion preventing pipe and a joint coating method, and more particularly, to a brassing process (Step S1) for cleaning the surface of a steel pipe or a joint; An adhesive applying step (S2) of applying an adhesive to the surface of a steel pipe or a joint; A first butyl tape winding step (S3) of winding a double-base butyl tape on the surface of a steel pipe or a joint; A secondary butyl tape winding step (step S4) of winding a double-base butyl tape to the surface of a steel pipe or a joint in a secondary winding; And a coating liquid application step (step S5) of applying a polyurethane-based coating liquid to the surface of the steel pipe or joint after the secondary butyl tape winding step (step S4). In order to prevent corrosion of the pipe- And joints for pipe connection are coated on the surface of the joint, the double base tapes are wound twice and then the external coating agent is applied to prevent the corrosion of the joints for pipe and pipe connection, and the polyurethane- And polyurea can be mixed with each other. Therefore, it has excellent mechanical, physical and chemical properties, and can freely control the thickness required for the method. In addition, it is advantageous that the process is simple and the process cost is minimized, Invention.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method of coating pipes and joints,

The present invention relates to a method of coating a joint for pipe and pipe connection, and more particularly, to a method of coating a pipe and a pipe connection joint, The present invention relates to a corrosion preventing pipe and a joint coating method for preventing corrosion of a pipe and a pipe connecting joint by applying an external coating agent after winding the tape twice.

Generally, in order to prevent the corrosion of joints for pipe and pipe connection, it is necessary to protect the environment from corrosion environment such as plating, painting, spraying, . It is required to completely block the physical and chemical causes of corrosion by forming a conventional method layer on the surface of the body with excellent characteristics of oxygen and moisture shielding and insulation.

Currently, steel pipes, gas pipes, water pipes and plant piping products used as anti-corrosion products can be applied by cold applied tape, heat shrinkable sheet, Petrolatum coating method and epoxy products A product which is coated or heat shrunk or painted by using a coating material was used.

Applications include coating systems used to prevent corrosion of gas pipes, pipelines, water pipes, power plants, internal and external plant piping, underground buried pipes and exposed pipes, valves and uneven parts, and plates. Cold applied tape, heat shrinkable sheet and tape, Petrolatum, epoxy, etc. are used but the life of the pipe is prolonged according to the efficiency of the coating, so that the economic effect is great and many products have been developed according to the method.

This coating method is applied to the case where the steel pipe is coated directly on the surface directly from the factory or the coating is applied directly on the site. It is selected by the user according to the purpose of use and is applied to the method layer according to the use of the pipe. The thickness and the configuration of the product are different.

That is, conventional pipes used for various purposes in ships and other industries may be divided into straight pipes or deformation pipes depending on the shape thereof. Such pipes may be formed of corrosion that may occur during use, contamination by external foreign substances, and / or For the sake of insulation, the inner circumferential surface and / or the outer circumferential surface are coated.

Meanwhile, as a method of coating the inner circumferential surface and / or the outer circumferential surface of the pipe, there is a method of using a spray device for spraying a coating agent such as a coating liquid with the pipe, a method of coating a coating agent such as a coating powder on the inside and outside of the pipe, Method is common. The coating material required for the coating of such pipes is generally made of polyethylene (PE) which is highly resistant to corrosion and is economical. The particle size of the particles constituting such a pipe is related to the melting rate of the coating. Specifically, the difference in the melting speed during coating may have a negative effect on the tensile strength of the coated surface due to the completion of coating before the particles having a large particle size are melted.

However, since the coating agent is composed of particles having the same particle size, it has a low density. Processing of such a low-density coating agent lowers the coating efficiency and deteriorates the coating quality.

Current coatings include two-layer (adhesive + polyethylene) and three-layer (FBE + adhesive + polyethylene) coatings.

Therefore, it is difficult to control the quality of the products coated on the site according to the construction product and the workability.

In order to increase the efficiency of the system, it is necessary to increase the time and cost of preparation for preheating in order to remove the moisture on the surface of the tube or to improve the efficiency of the system. In addition to the difficulty of standardized installation, And there is a problem that it can not be managed.

A coating pipe and its coating method disclosed in Patent No. 0954277, which has been conventionally developed in view of the above-mentioned circumstances, is disclosed in the patent publication.

As shown in FIG. 1, the coating pipe and the coating method thereof are coated with a coating agent for a coating pipe. The coating pipe has a particle size average of 150 to 160 μm as shown in FIG. 2, Providing a coating with a plurality of particles formed of a linear low-density polyethylene (LLDPE) material having a particle size deviation of ² 탆; Heating the coating agent to a temperature of 150 DEG C or higher; applying the heated coating agent to an inner circumferential surface and / or an outer circumferential surface of the coating pipe; And air-cooling the heated coating agent.

The above-mentioned coating method can provide a high-density coating agent by the particle size difference, and it is expected to improve the coating efficiency according to the uniformity of the melting speed. However, since the polyethylene is non-polar, it is difficult to apply coating or post- It is inconvenient to oxidize the surface by using it. It is chemically very stable and does not dissolve in an organic solvent. In the case of a product using polyethylene, it is very difficult or impossible to bond, and in the case of a toy or a plastic model There is a problem that a coating process is complicated because it is impossible to adhere using polyethylene and another resin is used or when a polyethylene is used, a heat welding machine must be used.

The present invention has been made to solve the various drawbacks and problems caused by the conventional coating method described above, and it is an object of the present invention to apply an adhesive to the surface of a pipe and a pipe connecting joint in order to prevent corrosion of a pipe- And a method for coating an outer coating agent after winding a double base tapes tape twice to prevent corrosion of joints for pipe and pipe connection.

Another object of the present invention is to provide a polyurethane-based mixture with an external coating agent which can be used by mixing a polyurethane and a polyurea, so that it has excellent mechanical, physical and chemical properties and has excellent adhesion and non- And a joint coating method using the same.

It is another object of the present invention to provide a corrosion preventing pipe and joint coating method which is simple in the process and minimizes the cost required for the process, thereby providing excellent economical efficiency.

According to an aspect of the present invention, there is provided a corrosion prevention pipe and joint coating method comprising: a brassing step (S1 step) of cleaning a surface of a steel pipe or a joint; An adhesive applying step (S2) of applying a liquid adhesive to the surface of a steel pipe or a joint; A first butyl tape winding step (S3) of winding a double-base butyl tape on the surface of a steel pipe or a joint; A secondary butyl tape winding step (step S4) of winding a double-base butyl tape to the surface of a steel pipe or a joint in a secondary winding; And a coating liquid application step (step S5) of coating the surface of the steel pipe or the joint with a polyurethane based coating liquid after the secondary butyl tape winding step (step S4).

In order to prevent the corrosion of pipes and pipe connection joints, an adhesive is applied to the surfaces of joints for pipe and pipe connection, a double base tapes are wound twice, and then an external coating agent is applied to the joints It can prevent corrosion and can be mixed polyurethane and polyurea with polyurethane mixture by external coating agent. It has excellent mechanical, physical and chemical properties. There is a special advantage that the cost is minimized and the economical efficiency is excellent.

1 is a perspective view of a pipe coated with a conventional coating method,
2 is a flow chart showing the execution of the conventional coating method,
Fig. 3 is a flow chart showing the execution of the corrosion preventing pipe and joint coating method of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a corrosion preventing pipe and joint coating method according to the present invention will be described in detail as a preferred embodiment with reference to the accompanying drawings.

FIG. 3 is a flow chart of the corrosion prevention pipe and joint coating method according to the present invention, wherein the pipe and joint coating method of the present invention comprises a brassing process (Step S1) for cleaning the surface of a steel pipe or a joint; An adhesive applying step (S2) of applying a liquid adhesive to the surface of a steel pipe or a joint; A first butyl tape winding step (S3) of winding a double-base butyl tape on the surface of a steel pipe or a joint; A secondary butyl tape winding step (step S4) of winding a double-base butyl tape to the surface of a steel pipe or a joint in a secondary winding; And a coating liquid application step (S5 step) in which the surface of the steel pipe or joint is coated with a polyurethane-based coating liquid after the secondary butyl tape winding step (step S4).

In the adhesive application step (step S2), a liquid adhesive is applied to the surface of the steel pipe or joint by brushing or spraying.

In addition, the butyl tape is rolled up by 50% in the primary butyl tape winding step (S3 step) and the secondary butyl tape winding step (S4 step).

The coating liquid to be applied in the coating liquid application step (S5 step) is preferably a mixture of 10 to 15% by weight of polyurethane and 85 to 90% by weight of polyurea.

As described above, the corrosion preventive pipe and joint coating method of the present invention is characterized in that the surface of a steel pipe is blasted in the manner of a steel pipe pipe or a joint, and a liquide adhesive or a hot melt adhesive having strong adhesion to the surface of the steel pipe And then a double base butyl tape is wound up on the upper portion and then a polyurethane-based mixture is applied.

Hereinafter, embodiments of the corrosion preventing pipe and joint coating method of the present invention will be described in detail.

Example

First, the surface of the steel pipe or joint to be coated was cleaned in the brassing process (S1 step).

If the foreign body is attached to the surface of the gypsum body, the efficiency of the coating deteriorates. Therefore, the gypsum layer is cleaned and the surface is brushed.

Subsequently, in the adhesive applying step (step S2), an adhesive is applied by brushing or spraying in an adhesive applying step (step S2) of applying an adhesive to the surface of a steel pipe or a joint.

In order to protect the surface of the steel pipe from the outside, it is important to bond with the material of the corrosion layer in order to make a strong liquid adhesive so that the corrosion layer adheres well to the surface of the steel pipe.

Thus, the liquid adhesive was prepared so as to have a flowability so as to be able to be rubbed with 60 to 65 wt% solvant, 27 to 30 wt% of butyl and solids, 5 to 7 wt% of adhesive, and 2 to 4 wt% of carbon.

Subsequently, a double base butyl tape is wound around the surface of the steel pipe or joint in the primary butyl tape winding step (S3 step), and the secondary butyl tape winding step (step S4) Step S3), the double-base butyl tape was wound in a 50% overlapping manner.

In order to completely adhere to the liquid adhesive, the double-base butyl tape which is a method layer is formed by winding a butyl tape on both sides of a mastic made of butyl as the main material, one side being bonded to the surface of the steel pipe, Was used as a base tape.

The properties of butyl are unchanged, the bonding is complete and the workability in the field is good.

When only one side is bonded by a method layer, the coating is not completely applied to the coating forming the outer coating, so that the coating efficiency is lowered because the pores are not formed or bonded. However, the coating on both sides of the tape and the outer protective layer is completely completed.

At this time, the double base butyl tape wound in the first butyl tape winding step (step S3) and the double base butyl tape wound in the second butyl tape winding step (S4 step) are overlapped by 50%.

  Double base butyle tape is extruded by a triple layer extruder in a tee die and extruded from the center of the die to extrude a high density polyethylene (HDPE) On both sides of the die, double-base butyl tape (double-sided extruded tape) is made of butyl-based mastics.

Finally, in the coating liquid application step (step S5), the coating liquid was applied to the surface of the steel pipe or joint using a polyurethane-based coating liquid. That is, it is applied to the outside of the double base butyl tape (double base butyle tape) with a polyurethane-based coating liquid.

Here, the coating liquid is a two-pack type elastic material prepared by branding 10-15% by weight of polyurethane and 85-90% by weight of polyurea, and is a two-pack type elastic material having instant adhesion and high strength. It has excellent chemical properties, good workability for continuous coating, and the thickness of coating can be freely adjusted.

While the present invention has been described with reference to the preferred embodiments, it is to be understood that the invention is not limited thereto and that various changes and modifications may be made therein without departing from the scope of the invention.

Claims (5)

delete delete A brassing step (S1 step) of cleaning the surface of the steel pipe or joint; An adhesive applying step (S2) of applying a liquid adhesive to the surface of a steel pipe or a joint; A first butyl tape winding step (S3) of winding a double-base butyl tape on the surface of a steel pipe or a joint; A secondary butyl tape winding step (step S4) of winding a double-base butyl tape to the surface of a steel pipe or a joint in a secondary winding; And a coating liquid application step (S5 step) of applying a polyurethane coating liquid to the surface of the steel pipe or joint after the secondary butyl tape winding step (step S4), the method comprising:
Wherein the liquid adhesive has a composition of 60 to 65 wt% solvant, 27 to 30 wt% of butyl and solids, 5 to 7 wt% of adhesive, and 2 to 4 wt% of carbon. delete delete

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