JP3613536B2 - Anti-corrosion method for pipe mount - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preventing corrosion at the base of these pipes that are most susceptible to corrosion in zinc-made metal pipes, specifically, various steel pipes including stainless steel pipes.
[0002]
[Prior art]
Various types of indoor or outdoor metal pipes are supported and fixed by mounts arranged at predetermined intervals, but dust or water tends to stay in the gap between the mounts and the pipes, and the temperature of the atmosphere or transport fluid changes. Sliding due to thermal expansion / contraction of the piping itself due to the inevitable, the coating film is easy to peel off. For this reason, the site | part where piping contact | connects a mount part will be rusted earliest. Conventionally, as a method for preventing corrosion of the portion of the pipe that contacts the gantry, in addition to painting, a method of interposing a zinc plate between the pipe and the gantry as described in Japanese Patent Publication No. 63-44828, or stainless steel There is a method of applying a two-component mixed adhesive to a plate and bringing it into intimate contact with the part.
[0003]
However, if the coating method is peeled off by sliding, rusting is unavoidable even if it is applied in multiple layers. In addition, the method of interposing a zinc plate may cause fatigue corrosion cracking because the load applied is large and corrosive, and white rust is generated on the outside air. There wasn't. Although the method of applying the adhesive to the stainless steel plate is resistant to sliding, water may invade through minute defects in the adhesive layer and may cause pitting corrosion.
[0004]
[Problems to be solved by the invention]
The present invention provides an anticorrosion method that solves the conventional problems as described above, effectively delays the progress of local corrosion in a pipe pedestal, and can extend the life of the entire pipe by simple construction. It is intended.
[0005]
[Means for Solving the Problems]
The anticorrosion method in the pedestal part of the pipe according to the present invention includes the following (a) to (a) to the length of the pipe in contact with the pedestal or beyond the part or the entire curved surface of the pipe including the part in contact with the pedestal. The said subject was achieved by sticking the anticorrosion member made into the layer structure shown to d) so that the adhesive layer might contact | connect a piping, and mounting piping on a mount part.
(A) A pressure-sensitive adhesive layer that contains zinc powder and can be imparted with conductivity when pressed (b) a zinc plate (c) a resin film (d) a stainless steel plate
In addition, the adhesive layer in the anticorrosion member of this invention can be continuously provided in the peripheral part which contact | connects piping, and shall not be provided inside. And it is preferable that the amount of zinc powder contained in the pressure-sensitive adhesive layer in the anticorrosive member is 60 to 95% by weight. If the pipe is pre-painted, the paint is peeled off at the part where the mount receives the load of the pipe.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the anticorrosion method for a pipe mount according to the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory view schematically showing a steel pipe to which the method of the present invention is applied. In FIG. 1, 6 is a steel pipe as a pipe. In the present invention, the steel pipe includes a stainless steel pipe, and in principle, it can be applied to all metal pipes that can use the base potential of zinc. In the description, an example in which a steel pipe is used as the pipe is shown. An anticorrosion member 8 is attached to a portion of the steel pipe 6 in contact with the gantry 7 with a stainless steel attachment band 5. As shown in FIG. 2, the anticorrosion member 8 is configured by sequentially laminating an adhesive layer 1, a zinc plate 2, a resin film 3, and a stainless steel plate 4 that contain zinc powder and can be imparted with conductivity when pressed. Hereinafter, each structure of these anticorrosion members and the case where they are attached to a steel pipe will be described.
[0008]
In the present invention, the pressure-sensitive adhesive layer 1 of the anticorrosion member is capable of imparting conductivity during pressing by containing zinc powder. The anticorrosion member 8 is disposed so that the pressure-sensitive adhesive layer side is in contact with the steel pipe 6, and the pressure-sensitive adhesive layer 1 prevents water from entering between the anticorrosion member 1 and the steel pipe 6. Acts as a sealant. In addition, since zinc powder is contained, water that penetrates through minute defects in the pressure-sensitive adhesive layer 1 reacts with zinc and becomes alkaline, leading the steel to a passive region and suppressing the progress of corrosion. If the steel pipe 6 does not have an insulator such as a coating film, the zinc powder in the conductive pressure-sensitive adhesive layer acts as a sacrificial anode for the steel and exhibits an anticorrosive action. Prevent rusting. The composition of the pressure-sensitive adhesive layer 1 is obtained by containing 60 to 95% by weight of zinc powder in a neutral butyl rubber resin or the like. When the zinc powder content is less than 60% by weight, the anticorrosive effect becomes dilute, and when it exceeds 95% by weight, the action as a sealant is lowered. When the zinc concentration is high within the zinc powder content range, the zinc powders are brought into contact with each other even if they are not pressed to show conductivity, but more stable conductivity is achieved by pressing between the powders even when the zinc concentration is low. Obtained by contact. In the present invention, the anticorrosion member 8 is placed on the gantry 7 in a state of being in close contact with the steel pipe 6, so that a pressing force is applied. In actual construction, a paste-like adhesive whose viscosity has been reduced by adding a solvent is applied to the zinc plate 2 to a thickness of preferably 0.2 to 2 mm, and is then brought into close contact with the steel pipe 6.
[0009]
FIG. 3 shows another embodiment of the anticorrosion member applied to the present invention. The layer structure of the stainless steel plate 4, the resin film 3, and the zinc plate 2 is the same as that of FIG. It is not applied to the entire surface of the zinc plate 2, and is applied only to the entire periphery of the anticorrosion member 8 when the anticorrosion member 8 is attached to the steel pipe 6, and is not applied to the inside of the contact portion. In this case, the pressure-sensitive adhesive layer 1 acts as an anticorrosive sealant, and the anticorrosive action is mainly handled by the zinc plate 2 as a sacrificial anode.
[0010]
The zinc plate 2 in the anticorrosion member 8 functions to suppress the progression of rust by transferring the water that has entered in spite of the presence of the pressure-sensitive adhesive layer 1 to the alkali side by corrosion of zinc and moving the environment to the passive region of steel. To do.
[0011]
In the structure of the anticorrosion member 8 in FIG. 2, when the adhesive layer is pushed by the weight of the steel pipe and the zinc plate 2 is in direct electrical contact with the steel pipe 6, or as in the layer structure shown in FIG. When the steel pipe 6 is in direct contact, the zinc plate 2 exhibits an anticorrosive action as a sacrificial anode and suppresses the progress of rusting. As described above, the action of the zinc plate 2 is similar to that of the pressure-sensitive adhesive layer 1 containing zinc powder, but the zinc plate is a good conductor and is more reliable. The thickness of the zinc plate 2 depends on the corrosive environment and the amount of the adhesive layer 1 containing zinc powder, but is preferably about 0.1 to 2 mm.
[0012]
The resin film 3 has an effect of improving the handleability by adhering the zinc plate 2 and the stainless steel plate 4, but normally, since an insulating material is used, it acts as an insulator between them. In this case, since the zinc plate 2 and the stainless steel plate 4 are insulated, the stainless steel plate serves as a cathode and zinc serves as an anode, so that it is possible to prevent the zinc from being consumed for corrosion protection of the stainless steel plate 4. As the insulating resin film, a thermoplastic resin film is usually used, but it may be a thermosetting film or a normal adhesive or pressure-sensitive adhesive. On the other hand, when it is necessary to prevent the corrosion of the stainless steel plate by the sacrificial anticorrosive action of the zinc plate or zinc powder, a conductive film or adhesive layer mixed with particles of zinc, nickel, graphite or the like may be used. The resin film 3 preferably has a thickness of several + μm.
[0013]
The anti-corrosion member 8 laminated on the pedestal 7 part makes the anti-corrosion member 8 easy to slide together with the steel pipe 6 and plays a role as a high-strength material to prevent the anti-corrosion member 8 from breaking when sliding. It has the effect of preventing appearance deterioration due to corrosion of the outer portion. The thickness of these stainless steel plates 4 is preferably 0.2 to 2 mm, and the thickness is increased to withstand the load as the steel pipe diameter increases.
[0014]
When the steel pipes are coated, it is desirable that the steel pipes be sufficiently cleaned as a pretreatment of these steel pipes, and the coating is peeled off. However, it is necessary to remove the deteriorated coating film as a minimum. In particular, as shown in FIG. 3 as the anticorrosion member 8, when the zinc plate 2 is used as a sacrificial anode to exert an anticorrosive action, it is necessary to ensure electrical contact between the steel pipe 6 and the zinc plate 2. For this reason, when there is an insulator such as a coating on the steel pipe, the contact point between the base and the steel pipe, which is the minimum load and is easy to obtain metal contact, is usually linear, but the coating etc. It is desirable to peel off. Of course, this is the same when pipes other than steel pipes are used.
[0015]
The size of the anticorrosion member 8 formed by stacking as shown in FIGS. 2 to 3 may cover the entire circumference in the circumferential direction of the steel pipe 6, but about 1/3 of the circumference including the tangent to the gantry 7. If there is enough. The length direction needs to be equal to or longer than the length of the tangent line with the gantry 7 and may be longer than the gantry 7 in consideration of the movement of the tube accompanying expansion and contraction and the mounting band cost of the laminated anticorrosion member 8. preferable.
[0016]
In order to attach the anticorrosion member 8 to the steel pipe 6 in close contact, the anticorrosion member 8 which has the layer structure of FIGS. 2 to 3 but is not formed by coating the adhesive layer 1 is bent according to the pipe diameter. Then, the adhesive layer 1 containing zinc powder is applied on the zinc plate 2, and most of the solvent is volatilized and attached to the steel pipe 6, and both ends are tightened with attachment bands 5 such as stainless steel. It is preferable to carry out the procedure.
[0017]
In addition, after attaching the anticorrosion member 8 to the steel pipe 6 according to the method of the present invention, it is possible to apply a coating so as to cover the portions of the anticorrosion member 8, thereby eliminating the appearance problem. Examples are shown below.
[0018]
【Example】
A 200 mm long 200A steel pipe painted with a modified epoxy-based intermediate coating and acrylic silicon-based top coating, a 100 mm long, 40 mm wide C channel, and a 200A U-bolt combination. A corrosion acceleration test was conducted. As an example of the method of the present invention, the outer diameter of a 200A steel pipe is formed by three rolls of a 130 × 220 mm plate obtained by thermocompression bonding of a 1 mm thick pure zinc plate, a 30 μm polyolefin resin film, and a 0.3 mm thick SUS304 stainless steel plate. The adhesive was mixed with 85% by weight of zinc and the remaining butyl rubber as an organic material mixed with a solvent (ZAP paste, manufactured by Mitsui Mining & Mining Co., Ltd.). The one extended with a spatula to 1 mm was used. After holding for 30 minutes in order to volatilize the solvent of this adhesive, it was applied to a steel pipe and tightened using two stainless steel mounting bands having a width of 10 mm. In addition, the coating film of the steel pipe was removed linearly over a width of 10 mm and a length of 100 mm, and an anticorrosion member was applied around the removal line.
[0019]
The specimen adjusted as described above was placed on the C channel with the coating film removal line directly below, and fixed with a U bolt. The fixing tightening torque was 200 kg-cm. The specimens were subjected to a combined cycle corrosion test together with a pair of paint only as a comparative example. Cycling conditions are 1 hour, salt spray in an environment of 40 ° C, then placed in dry conditions (50 ° C x 20% humidity) for 5 hours, and then placed in wet conditions of 40 ° C x 95% humidity for 2 hours. It was. This cycle was performed 38 times and then taken out and mechanically shifted while the 10 mm pipe and C channel were fixed with U bolts, and further subjected to a combined cycle test of 20 cycles. After the test, the anticorrosive member was removed from the specimen of the embodiment of the present invention and inspected, but no rusting was observed in the part, whereas in the comparative example, rusting occurred at the contact part between the C channel and the steel pipe. Was recognized.
[0020]
【The invention's effect】
According to the present invention as described above, it is possible to effectively delay the progress of local corrosion in the gantry of the pipe, to prolong the life of the entire pipe by simple construction, and to provide a desirable anticorrosion method from the exterior. In line with the needs of the industry.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a schematic explanatory diagram showing an example when a method of the present invention is carried out.
FIG. 2 is an explanatory view showing an example of an anticorrosion member applied to the method of the present invention.
FIG. 3 is an explanatory view showing another example of the anticorrosion member applied to the method of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Adhesive layer containing zinc powder 2 Zinc plate 3 Resin film 4 Stainless steel plate 5 Mounting band 6 Steel pipe 7 Base 8 Corrosion-proof member

Claims (4)

A layer configuration shown in the following (a) to (d), including a part of the circumference of a metal pipe noble than zinc including a part in contact with the gantry or a length of the whole pipe in contact with the gantry or beyond the length An anticorrosion method for a pipe mount, wherein the anticorrosive member is brought into close contact with the pipe so that the adhesive layer is in contact with the pipe, and the pipe is placed on the mount.
(A) A pressure-sensitive adhesive layer that contains zinc powder and can be imparted with conductivity when pressed (b) zinc plate (c) resin film (d) stainless steel plate Corrosion method in gantry of the pipe according to claim 1, wherein the adhesive layer in the anti-corrosion member is not given therein granted continuously to the peripheral portion in contact with the pipe. 3. The anticorrosion method for a pipe pedestal according to claim 1, wherein the coating previously applied to the pipe is peeled off at a portion where the pedestal receives a load of the pipe. The method for preventing corrosion in a pipe mount according to any one of claims 1 to 3 , wherein the amount of zinc powder contained in the pressure-sensitive adhesive layer in the anticorrosion member is 60 to 95 wt%.

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