JPH0233432B2 - KOKANNONAIMEN RAININGUHO - Google Patents

Description

[Detailed description of the invention] (Summary of the invention, industrial application field) This invention supplies a fluid hardening resin liquid, which is a component of resin mortar, to the inner surface of a steel pipe rotating at a low speed. Then, the rotational speed of the steel pipe is increased, a filler (such as aggregate) is supplied, and the inner surface of the steel pipe is sequentially coated with the resin liquid and the filler, so that the steel pipe is rotating at a high speed. The high centrifugal force generated by the steel pipe forcibly promotes the blending of the resin liquid and filler on the inner surface of the steel pipe, thereby preparing a resin mortar composition on the inner surface of the steel pipe.At the same time, a thin layer of this resin mortar composition (lining The present invention relates to a method of lining the inner surface of a steel pipe with a cured resin mortar coating layer by forming a resin mortar layer) and finally curing the curable resin liquid of this resin mortar layer.

The steel pipe with a hardened resin mortar coating layer on the inner surface obtained by the lining method of the present invention has excellent corrosion resistance and protective coating properties, and is suitable as a material for construction and civil engineering. It becomes a useful basic material.

(Prior art) In order to prevent corrosion on the inner surface of steel pipes, various coating materials,
Various methods of covering with lining materials etc.
For example, (1) a powdered thermoplastic resin is uniformly adhered to the surface of a heated steel pipe by electrostatic coating, fluidized dipping, etc. to form a molten coating film; (2) Spraying or coating a thermosetting resin liquid to form a thin film of the resin liquid, and then curing the thin film of the resin liquid to cover the surface. Some methods have been implemented.

(Problems to be Solved by the Invention) The method (1) described above involves quite complicated processes such as preheating the steel pipe, forming an adhesive layer, and forming a coating layer using powdered thermoplastic resin. A steel pipe having a coating layer formed from a powdered thermoplastic resin by the method described in ) has an anticorrosion coating layer that has physical properties such as heat resistance, abrasion resistance, and hardness depending on the use of the steel pipe coated with the anticorrosion coating. , was not necessarily sufficient.

In addition, the coating method using a thermosetting resin liquid according to method (2) above still does not provide satisfactory physical properties such as abrasion resistance and impact resistance.
In addition, when these thermosetting resin liquids are sprayed or applied to the inner surface of steel pipes, they often drip downward before being thermoset. However, it has the disadvantage that a non-uniform coating layer is formed, making it difficult to form a uniform coating layer or a thick coating layer. In addition, if the curing speed of the thermosetting resin is increased to prevent the above-mentioned dripping, the storage stability of the resin liquid deteriorates, and the coating operation must be shortened, making it difficult to form a uniform coating layer. becomes extremely difficult.

On the other hand, high viscosity resin mortar, in which a high proportion of fillers such as aggregates are blended into a curable resin liquid, is used in the construction and construction fields for its chemical resistance, heat resistance, abrasion resistance, hardness, and impact resistance. Because it forms a hardened layer with excellent physical properties such as hardness, it is generally used to form flat floors in buildings, and it is also sometimes used to coat the surfaces of other flat materials. However, due to the high viscosity of the resin mortar, the coating work was mostly carried out by hand using a trowel, etc., similar to general cement mortar. However, forming an anti-corrosion coating layer on the inner surface of a steel pipe requires skill, and it may not be possible to line the inside of a steel pipe with a small diameter that cannot be accessed by humans. There was no known coating method.

(Means for Solving the Problems, Effects) The inventors have developed a steel pipe having a hardened coating layer of resin mortar on its inner surface, which has excellent physical protection performance, in order to avoid the above-mentioned problems. As a result of intensive research into a ``method for lining the inner surface of steel pipes'' that would enable efficient manufacturing, we first applied or sprayed a fluid curable resin liquid onto the inner surface of a steel pipe that was rotating at low speed. Immediately, the rotational speed of the steel pipe is considerably increased, and filler such as aggregate for resin mortar is sprinkled on the thin layer of resin liquid on the inner surface of the steel pipe. A high centrifugal force is applied to the curable resin liquid and filler on the inner surface of the steel pipe to quickly form a resin mortar layer in which a high proportion of filler such as aggregate is blended into the curable resin liquid, and then, The present invention was completed based on the discovery that a hardened resin mortar coating layer can be easily applied to the inner surface of a steel pipe by hardening the hardening resin liquid of the resin mortar layer.

That is, this invention supplies a fluid curable resin liquid to the inside of the steel pipe while rotating the horizontally arranged steel pipe at a low speed about its central axis as the rotation axis, thereby forming a thin layer of the resin liquid. is formed on the inner surface of the steel pipe, and then the rotational speed of the steel pipe is increased, and a fine filler is supplied into the interior of the steel pipe to scatter the filler on the thin layer of the resin liquid, and the By applying a centrifugal force of approximately 1.5 to 12.5 G to the thin layer of resin liquid and the filler, a resin mortar layer in which the resin liquid and the filler are uniformly blended is formed, and finally The present invention relates to a method for lining the inner surface of a steel pipe, which is characterized by curing the curable resin liquid in the resin mortar layer.

This invention is a novel method for lining the inner surface of steel pipes, which allows a hardened resin mortar coating layer with excellent physical properties to be easily formed on the inner surface of steel pipes with excellent industrial reproducibility. (trowel)
There is no need to use etc.

In particular, this invention uses a "flowable hardening resin liquid" that can be applied uniformly by spraying, etc. to uniformly apply a thin layer of resin liquid to the inner surface of a steel pipe that is rotating at a low speed. Immediately, ``increase the rotational speed of said steel pipe'' and sprinkle a filler (such as aggregate) on the thin layer of resin liquid on the inner surface of the steel tube. By applying a large centrifugal force to the thin layer of resin liquid and the filler, forcibly promoting the blending of the thin layer of resin liquid and the filler, and forming a high viscosity resin mortar layer, steel pipes can be made. This makes it possible to quickly form a cured resin mortar coating layer of uniform thickness on the inner surface of the mold, and this point is the most distinctive and important point of the present invention.

A steel pipe having a resin mortar hardened coating layer formed by the lining method of the present invention on its inner surface is
The anticorrosion coating layer on the inner surface has excellent physical properties similar to those of the original cured resin mortar containing fillers such as aggregate, such as chemical resistance, heat resistance, and Since it is a hardened layer that has physical properties such as abrasion resistance, hardness, and impact resistance, it has extremely high anticorrosion performance.

(Detailed Description of the Present Invention) The curable resin liquid used in the present invention has a rotational viscosity of approximately 0.05 to 1000 at the temperature during the initial coating or spraying operation in the present invention. Poise, preferably 0.1-800
Any curable resin liquid with fluidity within a wide range of poise may be used. In this invention, even if the curable resin liquid is in a high viscosity range such as about 100 to 1000 poise, especially 250 to 800 poise, the increase in the rotational speed of the steel pipe after dispersing the filler Due to the large centrifugal force caused by this, the dispersed filler can be forcibly mixed into a thin layer of resin liquid of uniform thickness on the inner surface of the steel pipe easily and in a short time.

Furthermore, the curable resin liquid used in this invention is
It is preferable to have a pot life such that when applied or sprayed onto the inner surface of a steel pipe to form a thin layer of resin liquid, it does not harden until the next spray of filler is applied, i.e., about 10 minutes. It is appropriate that the curable resin liquid has a pot life of about 2 hours, especially about 20 minutes to 1 hour.Furthermore, when coated on the inner surface of the steel pipe and cured, it has a pot life of about 2 hours, especially about 20 minutes to 1 hour. It is preferable that the main component is a curable resin that acts as a binder and has the ability to bond to the inner surface of the steel pipe to be coated with sufficient adhesive force.

In this invention, as the curable resin liquid, thermosetting resins, room temperature curable resins, etc. used in ordinary resin mortars are mainly used, as long as they have the rotational viscosity described above at the temperature of the coating or spraying operation. All of the component resin liquids can be used; for example, the main component is a two-component curable resin such as epoxy resin, unsaturated polyester resin, or polyurethane resin, and contains appropriate curing agents, additives, etc. Examples include uncured liquid materials.

The filler used in this invention is preferably one that does not particularly accelerate the curing of the thin layer of the curable resin liquid formed on the inner surface of the steel pipe, and Properties, shapes, and sizes that can be easily dispersed or sprayed onto a thin layer of resin liquid by a known method, and that can also be easily incorporated into the thin layer of resin liquid by the aforementioned centrifugal force. For example, aggregates such as pulverized stone powder for cement mortar, fine sand, and silica sand having the above-mentioned properties, or thermoplastic resins or thermosetting Typical inorganic fillers such as short glass fibers, glass powder, glass flakes, calcium carbonate, talc, alumina, various short metal fibers, and metal powders, which are blended into plastic resins as reinforcing agents, as well as various inorganic colorants, etc. can be preferably mentioned.

In this invention, the filler is particularly
The angle of repose of the steel pipe, which indicates its self-flowing property, is approximately 100° or less, particularly 80° or less, as measured by the injection method, or approximately 120° or less, particularly 100° or less, as measured by the spatula angle. This is preferable because it easily penetrates into the thin layer of resin liquid on the inner surface due to the above-mentioned centrifugal force.

In addition, the particle size of the filler or the maximum cross-sectional diameter of the short fibers is about 1/2 the thickness of the resin mortar layer (the layer that is finally formed) formed on the inner surface of the steel pipe. Below, the particle size or the maximum diameter of the cross section of short fibers must be approximately 0.001 to 1000 μ, especially 0.01 The thickness should be within the range of ~500μ to ensure sufficient penetration of the resin liquid between the fillers, to prevent the formation of voids or bubbles between each resin mortar layer, and to prevent peeling or chipping between each layer. Furthermore, it is preferable that the short fiber filler has a length of about 2 cm or less, particularly about 0.01 to 10 mm, for the same reason as mentioned above.

The lining method of the present invention applies, for example, to the inner surface of a horizontally arranged steel pipe that is rotating at a low rotational speed of about 1 to 50 rpm, especially about 2 to 20 rpm, about the central axis of the steel pipe. Then, a predetermined amount of the above-mentioned fluid curable resin liquid is used, and the curable resin liquid is sprayed by air spray or airless spray at a temperature that does not cause curing of the curable resin liquid (at room temperature or under heating, particularly preferably at about (at a temperature of 0 to 60℃), or by pouring a fluid resin liquid into the rotating steel pipe and spreading it uniformly on the inner surface of the steel pipe.
Alternatively, a thin layer of curable resin of uniform thickness is first applied to the inner surface of the steel pipe by applying the resin liquid onto the surface of a coating roll and pressing the roll against the surface of the steel material. Form.

In addition, in this invention, when applying or spraying the hardening resin liquid onto the inner surface of the steel pipe, if the steel pipe is rotated at an excessively high rotational speed from the beginning, a thin layer of resin liquid with a uniform thickness may be formed. Therefore, the rotational speed of the steel pipe during formation of the thin layer of the resin liquid is preferably such that a centrifugal force of about 1 G or less is applied to the formed thin layer. However, after a somewhat uniform thin layer of resin liquid has been formed, it may be preferable to increase the rotational speed of the steel tube to a fairly high speed.

In the lining method of this invention, it is most suitable from the viewpoint of workability to form a thin layer of the resin liquid on the inner surface of the steel pipe by pouring or spraying the curable resin liquid. be. The method of forming a thin layer of resin liquid using this "spray" is to form a uniform thin layer of resin liquid by moving the spray nozzle or by moving it in the longitudinal direction of the rotating steel pipe to be coated. It is suitable because it can form a coating layer on a portion of the steel pipe to be coated, and it can further improve productivity and workability.

In the above method for forming a thin layer of resin liquid using a spray, the curable resin liquid used has a temperature of about 0.5 to 300 poise, particularly about 1 to 200 poise, at the temperature at the outlet of the spray nozzle during the application or spraying operation. This is preferable in order to perform uniform spraying.

In the coating method of the present invention, the method of spraying and adhering the filler (aggregate, etc.) onto the thin layer of resin liquid on the inner surface of the steel pipe whose rotation speed is set to high is, for example, simply , a fine filler can be sprinkled inside a rotating steel pipe by dropping it from above the inner surface of the steel pipe, or it can be dispersed in a container with a slit (cylindrical, toy-shaped, dish-shaped, etc.) placed inside the steel pipe. By moving the container or moving or rotating the steel pipe, the filler is supplied from the slit of the container at a constant feeding rate (approximately 0.1 to 3.0, especially 0.3 to 1.5 g/ A method of spraying the filler by dropping it onto the inner surface of the steel pipe in a strip at a feed rate of about ¹⁰⁰ min/cm Examples include a method of dispersing the water.

In the above-mentioned spraying of the filler, the amount of filler supplied onto the resin liquid on the inner surface of the steel pipe is determined by the amount of filler that can form a resin mortar layer with a preferable composition ratio,
In other words, it is preferable to supply the filler in an amount 1 to 10 times the volume of the resin liquid, but it may be supplied in excess. It can be recovered from above using any suitable method.

In the lining method of this invention, as mentioned above,
By scattering and depositing a fine filler (such as aggregate) on the thin layer of resin liquid on the inner surface of the steel pipe at increased rotational speed, the resin liquid layer and the filler are initially separated in appearance. Although the layers are connected in layers, the rotational speed of the steel pipe is increased (e.g.
When the viscosity of the resin liquid is 100 to 1000 poise and the inner diameter of the steel pipe is approximately 400 mm, the circumferential speed of the steel pipe should be approximately 1.6 to 5.0 m/sec, especially approximately 2.0 to 4.9 m/sec). Large centrifugal force (approximately 1.5 to 12.5G,
(preferably 2.0~12.0G) for a short period of time.
For example, for about 0.01 to 10 minutes, especially 0.1 to 5 minutes, the filler is forced to penetrate or permeate into the thin layer of resin liquid, or the resin liquid fills between the fillers without any gaps. The final product has a high rotational viscosity of about 500 poise or more, especially 1000 poise or more at room temperature, or is substantially non-flowing.
The entire resin mortar layer is uniform.
Therefore, the time required for the above-mentioned homogenization after the filler has been sprayed, that is, the time required for the curable resin liquid to ooze out onto the upper surface of the filler layer and cover the surface, is extremely shortened. It was done. Such an effect is difficult to achieve when the centrifugal force is less than 1.5G, and when the centrifugal force exceeds 12.5G, the dispersion state of the resin liquid and the filler changes due to the difference in specific gravity. This causes unevenness and makes it difficult to form a uniform resin mortar layer.

In addition, in this invention, the composition ratio of the resin mortar layer described above is such that the volume of the filler is preferably 1 to 10 times the volume of the curable resin liquid, particularly 1.5 to 8 times the volume of the curable resin liquid. .

In addition, in this invention, by making the volume of the blended filler considerably smaller than the amount of resin liquid, the resin liquid layer that oozes out on the surface of the filler layer can be formed into a smooth surface layer. Therefore, for such purposes, it is appropriate to reduce the volume of the filler blended to about 1 to 5 times that of the resin liquid.

In this invention, the thickness of the resin mortar layer is about 100 to 2000μ, especially about 200 to 1000μ, in order to form a coating layer with a uniform thickness without voids or bubbles, or from the viewpoint of workability. It is appropriate from

In this invention, when supplying the filler to the thin layer of resin liquid formed on the inner surface of the steel pipe, the rotational speed of the steel pipe can be increased all at once to a high circumferential speed. It is preferable to increase the circumferential speed. That is, when the filler is sprayed onto a thin layer of thermosetting resin liquid on the inner surface of the steel pipe, for example when the inner diameter of the steel pipe is approximately 400 mm, the first stage of filler supply is performed using a centrifugal By setting the circumferential speed of the steel pipe to approximately 2.0 to 3.0 m/sec so that the force is 2.0 to 4.6 G, penetration of the resin liquid into a thin layer is promoted, and a uniformly mixed resin mortar is created. After forming the resin mortar layer, the peripheral speed of the steel pipe is increased to about 3.0 to 5 m/sec so that the centrifugal force is 5.0 to 12.5 G, so that the resin mortar layer is sufficiently thickened. It is preferable to compact the resin mortar layer, or to sufficiently exude the resin liquid onto the surface of the resin mortar layer to form a thin, smooth resin layer on the surface.

In the lining method of the present invention, the operations of forming a thin layer of the curable resin liquid, dispersing (or spraying) the filler, and forming the resin mortar layer are as follows:
Basically, by performing each process once, a thick resin mortar layer (2 to 10 mm thick, especially 3 to 10 mm thick) can be formed.
If you want to obtain an even thicker resin mortar layer, repeat the above operation two or more times, and finally remove the curable resin contained inside this thick resin mortar layer. A thick hardened resin mortar coating layer can be formed on the inner surface of the steel pipe by curing it by heating or at room temperature.

Examples are shown below.

Example 1 Curable resin epoxy resin (manufactured by Yuka Ciel Co., Ltd.,
Epicote 828) 100 parts by weight, room temperature curing agent (manufactured by Yuka Ciel Co., Ltd., Epomate B001) 50 parts by weight, room temperature curing resin liquid (rotational viscosity at 25°C: 52 poise, 25°C
(Pot life: 25 minutes) 1.5 kg is supplied inside a steel pipe (inner diameter 400 mm, length 1 m) that is placed horizontally and rotates at a low circumferential speed of 1 m/sec or less with its central axis as the rotation axis. Then, the openings at both ends were closed, a thin layer of resin liquid was formed on the inner surface of the steel pipe, and the steel pipe was further rotated for 1 minute at a circumferential speed of 2 m/sec, until the film thickness was approximately A thin layer of 700 μm of resin liquid was formed and immediately supplied as a filler to a container (toy-shaped) having a ``slit with a width of about 2 mm and a length of about 20 cm'' installed inside the steel pipe. Standard sand (aggregate; Toyoura No. 5)
6 kg was supplied from the slit of the container at a rate of 0.7 g/cm ² ·min for about 10 seconds while vibrating the container.
Standard sand is dropped and scattered in a band on the inner surface of a steel pipe that is rotating at a circumferential speed of 2 m/s (centrifugal force 2.0 G), and it adheres to the inner surface of the rotating steel pipe that has a thin layer of the aforementioned resin liquid. and then further increase the circumferential speed of the steel pipe.
Increase the speed to 3 m/s (centrifugal force 4.6 G) and rotate for 3 minutes.
When the resin liquid oozes thinly onto the surface of the resin mortar layer, the surface is finished by lightly sliding it with a trowel to create a highly viscous, substantially non-flowing, uniform resin mortar layer. (thickness approx. 3
After confirming that a total of 2 mm, 1 volume of resin liquid, and 4 volumes of filler was formed, the rotation of the steel pipe was stopped. Thereafter, the steel pipe with the resin mortar layer formed on the inner surface is cured for about two weeks to harden the resin liquid in the resin mortar layer, and the inner surface of the steel pipe is coated with a hardened resin mortar coating layer (anticorrosion coating layer) with a thickness of 3 mm. ) was formed.

The thus obtained steel pipe having the anti-corrosion coating layer on its inner surface has an adhesion force of the resin mortar hardened coating layer to the steel pipe of 70 kg/cm ² and a compressive strength of the hardened coating layer of 850 kg/cm ² . The impact strength of the cured coating layer was 8.0 Kg·m, and the resin mortar cured coating layer had excellent long-term corrosion resistance.

Example 2 Unsaturated polyester as curable resin (phthalic anhydride 2.5 mol, fumaric acid 4.0 mol, adipic acid 3.5 mol)
100 parts by weight of a solution (condensation polymerized at a ratio of 10.3 moles of 1,6-hexanediol), 40 parts by weight of liquid rubber (manufactured by B.F. Gudrich, Hiker CTBM) as an additive, and methyl ethyl ketone peroxide as a curing catalyst. 1 part by weight, 0.2 part by weight of cobalt naphthenate as other additives, and 0.01 part by weight of hydroquinone (rotational viscosity at 25°C: 15 poise, pot life at 25°C: 30 minutes). The same operation as in Example 1 was performed to form a hardened resin mortar coating layer (anticorrosion coating layer) with a thickness of 2.5 mm on the inner surface of the steel pipe.

The steel pipe having the anti-corrosion coating layer thus obtained has an adhesion force of the resin mortar hardened coating layer to the steel pipe of 100 Kg/cm ² , a compressive strength of the hardened coating layer of 700 Kg/cm ² , and a The impact strength of the cured coating layer was 11.0 Kg·m, and the resin mortar cured coating layer had excellent long-term corrosion resistance.

Claims (1)

[Claims] 1. While rotating a horizontally arranged steel pipe at a low speed about its center axis, a fluid curable resin liquid is supplied to the inside of the steel pipe, and a thin layer of the resin liquid is applied to the inner surface of the steel pipe. and then increasing the rotational speed of the steel pipe and supplying a fine filler into the inside of the steel pipe to scatter the filler on the thin layer of the resin liquid, thereby forming a thin layer of the resin liquid. and the filler,
By applying a centrifugal force of about 1.5 to 12.5 G, a resin mortar layer in which the resin liquid and the filler are uniformly mixed is formed, and finally, the hardenability in this resin mortar layer is A method for lining the inner surface of steel pipes, which is characterized by curing resin liquid.