JPH0696831B2 - Cable wire for suspension bridge with anti-rust treatment - Google Patents

Description

The present invention relates to a cable wire for suspension bridges such as long bridges,
More specifically, it relates to a cable wire for a suspension bridge, which has a rust preventive treatment, that is, a white rust preventive treatment layer formed by galvanizing.

[Prior Art] For long bridges such as the Honshu-Shikoku connecting bridge, since most of these long suspension bridges are sea bridges, it is necessary to pull out the strands sequentially when laying the cable. It takes about 1 to 2 years to complete the cable. In addition, including the construction period and the completion of the main cable anticorrosion coating work,
The cable strands will be exposed to the sea for as long as five years.

For these reasons, anticorrosion treatment of cable wires is an essential requirement. Since suspension bridges are used for at least 100 years after completion, cable corrosion protection is very important as a factor in determining the life of the bridge. Conventionally, chemical conversion treatment with a chromic acid-based chemical has been carried out as a means for further preventing corrosion of the galvanized layer of the cable strand, but it has the drawback of causing environmental damage. As a means to prevent such pollution, a tannic acid-based coating (Japanese Patent Publication No. 55-1878)
No. 6), water glass coating (Japanese Patent Publication No. 55-30593) or organic / inorganic composite type coating composition (Japanese Patent Publication No. 62-40473 or Japanese Patent Publication No. 63-297613). .

[Problems to be Solved by the Invention] However, the conventional technologies have the following drawbacks, respectively, and none of them satisfy the present requirements.

The tannic acid type coating has a relatively good rust preventive effect under storage conditions such as in a warehouse where it does not get wet with rainwater, but because it is exposed to rainwater and exposed to thick rays outdoors during cable construction work. However, there is a problem that white rust occurs in a relatively short time.

Further, in the glass-based coating, potassium in the coating agent is easily dissolved in water, and this potassium is recrystallized during drying to form a whitened product, which is mistaken as white rust.

On the other hand, the organic-inorganic composite type coating composition has the characteristics such as film-forming property and flexibility of the organic polymer and the scratch resistance and weather resistance of the inorganic component. Although it is excellent as a white rust preventive treatment for wires, it may come into contact with rollers or guides during the cable pulling process during cable erection work or when strands are bundled in parallel, and part of the coating film may peel off. Has been pointed out.

As described above, the conventional means showed high corrosion resistance as intended in the laboratory or immediately after wire production, but it may be rubbed by rollers or the like during the strand manufacturing process or bent during strand processing. Therefore, there is a problem that the treated coating is cracked, or in the worst case, the coating film is peeled off. For this reason, when used as an actual cable strand, the actual rust prevention ability is lower than the original. In addition, the bridge is finally covered with multiple coatings (150 to 200 μm) on the entire main cable for protection against corrosion and aesthetics, but even with these multiple coatings, oxygen and water will be removed over the years. Since it cannot be prevented from penetrating through the coating film, it cannot be said that it can sufficiently withstand a severe corrosive environment.

Therefore, the zinc plating formed on the cable strands of suspension bridges has strong adhesion so that it will not fall off during transportation and cable erection work, and zinc corrosion even under outdoor conditions including sea breeze for several years at sea. It is required to form a rust-preventive protective coating that also has the rust-preventing ability to prevent

The present invention has been made under these circumstances,
The purpose is to provide a cable wire for suspension bridges that not only has the corrosion resistance of the rust-proof coating high, but also prevents the coating from being easily peeled off even when the treated wires are subjected to friction and bending that are ultimately received until the completion of the suspension bridge. To provide.

[Means for Solving the Problems] According to the present invention capable of achieving the above object, a hard galvanized wire having a tensile strength of 160 kg / mm ² or more is provided with a hot-dip galvanized layer having an adhesion amount of 300 g / m ² or more, and further A cable wire for suspension bridges, which is characterized in that an epoxy resin coating layer having a molecular weight of 10,000 to 30,000 is formed thereon at a coating amount of 5 to 15 g / m ² . Further, in the above constitution, a vaporizable rust preventive agent is added to the polymer epoxy resin used.
It is also effective to add 0.1 to 1.0% by weight, which can further improve the anticorrosion effect of the cable wire.

[Operation] In view of the above-mentioned various problems, the present inventors have conducted earnest researches, and as a result, as a result, as a result, hot-dip galvanizing was provided on the surface of the steel wire, and further, a polymer epoxy resin coating layer was formed. Or, it was found that all of the above problems can be solved by providing a coating layer in which a volatile rust preventive agent is added to a polymer epoxy resin (hereinafter, the letter "polymer" is omitted),
The present invention is completed here.

The structure of the cable wire for a suspension bridge according to the present invention has a hot-dip galvanized layer 2 on a hard steel wire 1, as shown in FIG.
Further, it has a double structure having a coating layer made of an epoxy resin or a vaporization rust preventive added to the epoxy resin.

As the hard steel wire 1 used in the present invention, for example, a piano wire or a wire material equivalent to SWRS77B defined in JIS G3502 is hot rolled, heat treated, or cold drawn to a predetermined wire diameter, and finally It is possible to use those having a tensile strength of 160 kg / mm ² or more and an elongation of 4.0% or more.

The hot-dip galvanized layer 2 can be provided by an ordinary means, but the amount of plating applied must be 300 g / m ² or more.
In other words, considering the service life of the suspension bridge, an adhesion amount of less than 300 g / m ² is insufficient. The upper limit is not particularly limited, but is preferably about 350 g / m ^{2 in} consideration of the plating process technology.

The coating layer 3 formed on the galvanized layer 2 has sufficient adhesion with the galvanized layer 2, suppresses the passage of moisture and the like, and prevents the surface of the galvanized layer 2 from being directly affected from the outside. It acts as a shielding film for preventing it.

The epoxy resin used in the present invention should have a high molecular weight as much as possible. That is, since the production of the cable wire goes through an in-line rustproofing process immediately after the galvanizing process, it cannot take a long time to dry the coating film.
Generally, the drying time is about 30 to 60 seconds, and in order to reliably form the epoxy resin layer in the rustproofing treatment line, it is necessary to use a resin having a high molecular weight as much as possible. is there. From the viewpoint of workability, the molecular weight of the epoxy resin is defined as 10,000 to 30,000 in the present invention. Epoxy resins are also excellent in dryness, adhesion, impact resistance and bending workability even when used alone, but it is also effective to use a melamine resin or blocked isocyanate resin together for crosslinking in order to further improve these properties. .

To form the epoxy resin layer on the surface of the galvanized steel wire, the resin is used as a solution in which it is dispersed in water or an organic solvent. When such a solution is applied onto the galvanized layer of hard steel wire and dried by heating, a transparent and glossy coating can be formed. The epoxy resin concentration of this solution should be 10 to 30% by weight.
If it is less than 10% by weight, it is difficult to obtain the coating amount of the present invention by one coating, and if it exceeds 30% by weight, the stability of the solution is poor and the workability is deteriorated. The coating amount should be 5 to 15 g / m ² . This is because when the coating amount is less than 5 g / m ² , the coating is damaged due to frictional flaws between cable strands and scratches during cable erection work, and sufficient rust prevention performance cannot be exhibited. Although the anticorrosive performance increases proportionally, 15 g / m ² is sufficient for this anticorrosive film to perform the anticorrosive action of the zinc plating layer until the final cable anticorrosion work. And the diameter of the wire increases, which also affects the diameter of the entire cable.

The cable for a suspension bridge according to the present invention is for the purpose of preventing corrosion of the galvanized layer, and since there is no untreated portion even in part, it is often possible to visually determine the presence of a treated coating,
Therefore, it is also effective to add a small amount of an appropriate pigment to the polymer epoxy resin solution to color the coating. As such a pigment, various pigments that are generally used may be used, but the addition amount is such that the coating is colored and should be kept as small as possible. Addition in a large amount adversely affects the corrosion resistance of the coating. Extend.

When using a vaporizable rust preventive agent, a solution obtained by adding a vaporizable rust preventive agent to an epoxy resin is applied on the galvanized layer of the hard steel wire and then dried by heating to 5 to 15 g / m ² The coating amount may be

Next, an example of the manufacturing procedure of the cable wire for suspension bridge according to the present invention will be explained. First, a hard steel wire is galvanized, and the surface is cleaned by degreasing, neutralization, water washing, brushing, etc., and then an epoxy resin. A solution or an epoxy resin solution containing a vaporizable rust preventive agent is sprayed, dipped, or applied by a flow coater, and quickly dried in an atmosphere of 200 to 400 ° C. At this time, the temperature of the coating is preferably raised to 170 to 220 ° C.

The volatile anticorrosive agent that can be used in the present invention,
For example, DICHAN [Dicylohexyl ammonium nitrite; (C
⁶ H ₁₁ ) ₂ NH ₂ NO ₂ ] or DIPAN [Diisopropyl ammonium n
Itrite; [(CH ₃ ) ₂ CH] ₂ NH ₂ NO ₂ ] and the like. Evaporative rust inhibitor itself vaporizes (sublimates) like naphthalene
Then, it adheres to the metal surface, covers it, and also fills and saturates the air surrounding the metal. When the water in the air condenses on the metal surface, it dissolves in this water, and the water reacts with the metal. It has the ability to prevent rusting. These vaporizable rust preventives gradually escape from fine pinholes and cracks in the coating film, and in particular fill the voids between the wire rods after strand processing, and continue to maintain the rust preventive effect. Evaporative rust inhibitor is 0.1
If it is less than 5% by weight, the residual rate in the film is deteriorated due to volatilization during heating and drying, and as a result, the rust preventive power after cable installation cannot be exhibited. On the other hand, if it exceeds 1.0% by weight, the formed coating itself becomes brittle, which lowers the adhesion of the coating and makes it expensive.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the following Examples are not of a nature limiting the present invention.
Any design changes that are made in the spirit of the later description are included in the technical scope of the present invention.

[Example] Example 1 350 g of hot dip galvanizing was applied to a piano wire of 5 mmφ (JIS G3502).
When plating is applied to the adhesion amount of / m ² and each composition shown in Table 1 is applied by dip coating, and dried for 60 seconds using a hot air circulation furnace set at 350 ° C. to form a rust preventive coating, The various performances of the coating are shown. The epoxy resins used at this time all have a molecular weight of 20,000. In Table 1, No. 1, 2,
3,4,5,8 are comparative examples, and Nos. 6,7,9,10 are cable wires for suspension bridges according to the present invention. Further, various performances of the anticorrosion coating shown in Table 1 were evaluated by the following methods.

(1) Adhesion test of anticorrosion coating Bend the test line along the corner of R = 5mm, and apply adhesive cellophane tape to the bent part to make it adhere and then peel it off.
The peeled area of the anticorrosion coating was investigated.

◯: No film peeling △: 1 to 5% film peeling ×: 5% or more film peeling (2) Corrosion resistance test of rust preventive coating Salt spray 48-hour test (JIS Z 2371) and wet 72 According to the time test (JIS K 2246).

◯: No white rust generation △: 1-10% white rust generation ×: 10% or more white rust generation (3) Ironing test = PWS processing simulation test As shown in Fig. 2, non-rotating roller (1,200φ) ), And the test line stretched while being bent was squeezed 5 times between rotating rollers as shown in FIG. After the ironing test, a 48-hour salt spray test and a 72-hour wet test were conducted to investigate the occurrence of white rust.

◯: White rust does not occur △: 1-10% white rust occurs ×: 10% or more white rust occurs As is clear from Table 1, all of the cable wires for suspension bridges according to the present invention have excellent coating adhesion and corrosion resistance as compared with Comparative Examples.

Example 2 350 g of hot-dip galvanizing a 5 mmφ piano wire (JIS G3502)
When plating is applied to an adhesion amount of / m ² and each composition shown in Table 2 is applied by dip coating, and dried for 60 seconds using a hot air circulation furnace set at 350 ° C., to provide a rust preventive coating, The various performances of the coating are shown. The epoxy resins used at this time all have a molecular weight of 20,000. In Table 2, N
o.11,12,13,16,19,20,21,22 are comparative examples, No.14,15,
17, 18 are cable wires for suspension bridges according to the present invention. Further, various performances of the rust preventive coatings in Table 2 were evaluated by the following methods for the atmospheric exposure test, and by the above methods (1) to (3).

(4) Atmospheric exposure test As shown in Fig. 4, 19 test lines were bundled in parallel and sealed at both ends.
After carrying out annual atmospheric exposure, the strand was opened and the occurrence of white rust was investigated.

◯: White rust does not occur △: 1-10% white rust occurs ×: 10% or more white rust occurs As is clear from Table 2, all of the cable wires for suspension bridges according to the present invention have excellent coating adhesion and corrosion resistance as compared with Comparative Examples.

[Effects of the Invention] As described above, according to the present invention, a cable wire that is excellent in corrosion resistance and coating adhesion and is optimal for suspension bridges was obtained.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic sectional view of a cable wire for a suspension bridge according to the present invention, FIGS. 2 and 3 are explanatory views showing an outline of an ironing test method, and FIG. 4 is an atmospheric exposure test. It is sectional drawing of a sample. 1 ... Hard steel wire, 2 ... Hot dip galvanized layer 3 ... Coating layer

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Yuyuki Miyagawa, 5-13-4 Honcho, Oji-cho, Kitakatsuragi-gun, Nara Prefecture (72) Izoo Hayashi, 3-12-35 Misaki Kusuha, Hirakata-shi, Osaka (56) References Japanese Laid-Open Patent Publication No. 1-280083 (JP, A) JP 60-14793 (JP, Y1)

Claims (2)

[Claims] 1. Adhesion amount to a hard steel wire having a tensile strength of 160 kgf / mm ² or more
A cable wire for a suspension bridge, wherein a hot dip galvanized layer of 300 g / m ² or more is provided, and an epoxy resin coating layer having a molecular weight of 10,000 to 30,000 is formed thereon with a coating amount of 5 to 15 g / m ² . 2. The adhesion amount to a hard steel wire having a tensile strength of 160 kgf / mm ² or more.
A hot-dip galvanizing layer of 300 g / m ² or more is provided, and a coating layer consisting of 99.0 to 99.9% by weight of an epoxy resin having a molecular weight of 10,000 to 30,000 and 0.1 to 1.0% by weight of a volatile rust preventive agent is further provided on the coating layer. Cable wire for suspension bridge, characterized by being formed with 15 g / m ² .