JPH073827A - Steel man-hole cover - Google Patents

Abstract

PURPOSE:To present spangles, or colorful colors of a plated coating, and promote corrosion proofing efficiency and rust proofing efficiency by susequently laminating zinc or zinc alloy plating, chemically formed on coating and coating film on the outside surface to form. CONSTITUTION:After blast treatment, pickling treatment, washing treatment and flux treatment are made to a steel man-hole cover 1, hot dip zincing is made. Then, after advance treatment is made to the man-hole cover 1, it is infiltrated into a phosphoric zinc bath, and a chemical conversion coating 3 of zinc phosphate is formed on a plating coating 2. After that, a primcoating film 5, a color coating film by a middle coating film 6 and a clear coating film 7 are laminated on the chemical conversion coating 3 to form a coating film 4. The clear coating film 7 can be formed on the chemical conversion coating 3 without appling the color coating film thereto.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron manhole cover which is plated with zinc or a zinc alloy and which has been painted.

[0002]

2. Description of the Related Art Iron manhole covers laid on the road surface are
Conventionally, it is generally used as it is without any special anticorrosion treatment, but there is one in which a part of the surface is washed and dipped in tar to form a tar film on the outer surface. However, the above tar film has weak adhesion and is easily peeled off in a short time.
As a result, the manhole cover that was laid near the coast, which is particularly vulnerable to salt damage, and the road surface, which was prone to various chemicals, was red and rusted, which made the cityscape worse.
This was especially noticeable on the recent color paved roads.

[0003]

Therefore, the present inventors
In order to prevent this rusting, we attempted to form a plating film by applying zinc plating after surface treatment such as alkaline degreasing, but the plating film alone is still insufficient in anticorrosion property, so in rainy weather etc. Slippery. Above all, just forming a plating film on the surface of the manhole cover poses a problem of environmental harmony. In other words, not only does the plating film on the manhole cover laid on the road surface glitter and give an unpleasant feeling, but when the sunbeam hits it, the reflected light enters the driver of the car, nearby houses, factories, etc. I realized there was a problem.

Therefore, an object of the present invention is to obtain an iron manhole cover which is excellent in corrosion resistance by applying a zinc or zinc alloy plating treatment and then applying a paint finish. Another object of the present invention is to obtain an iron manhole cover which eliminates the glittering feeling of the plating film and is environmentally friendly. Still another object of the present invention is to obtain an iron manhole cover which can utilize spangles (zinc crystal pattern) as a surface pattern during plating. Another object of the present invention is to obtain an iron manhole cover that forms a colored coating film on a plating film to make it colorful and matches a colored pavement. Still another object of the present invention is to obtain an iron manhole cover whose surface is excellent in slip resistance.

[0005]

As shown in the drawings, the iron manhole cover of the present invention has a zinc or zinc alloy plating film 2, a chemical conversion film 3, and a coating film 4 which are laminated in this order on the outer surface.

As the coating film 4, there is a clear coating film formed by direct coating on the chemical conversion coating 3 as shown in FIG. Separately, as shown in FIG. 3, a coating film 4 is composed of a colored coating film (5 and / or 6) formed by coating on the chemical conversion film 3, and a clear coating film 7 formed by coating on this colored coating film. can do. 2 or 3 constituting the coating film 4.
A transparent anti-slip material such as silica sand is mixed in the clear coating of.
Further, whiskers are added to the colored coating film in order to improve the coating film strength such as impact resistance.

[0007]

[Function] The plating film 2 is formed by plating after the plating pretreatment process. As the plating pretreatment step, when the target manhole cover is made of cast iron, shot blast treatment, pickling treatment, water washing treatment, and flux treatment are performed. In the case of a steel manhole cover, you may go through the same steps as cast iron, but after degreasing, washing with water, pickling,
After that, the same procedure as the previous step can be performed.

By sufficiently performing the shot blasting treatment, the carbon deposited on the surface of the manhole cover is removed as much as possible, and oil and iron oxide are removed, and especially in the case of casting, the foundry sand on the surface is removed. Furthermore, in shot blasting, by spraying small steel particles (shots) or steel crushed particles (grids), fine irregularities are formed on the entire surface of the manhole cover to roughen the surface, making it easier to attach the plating film thereafter. To do.

In the pickling treatment, for example, the manhole lid is immersed in a 7 to 20% hydrochloric acid aqueous solution heated to 15 to 35 ° C.,
This completely removes the oxide film on the surface. After that, it is washed with water and then fluxed. In the flux treatment, for example, the manhole cover is immersed in an aqueous solution of zinc ammonium chloride which is heated to 50 to 85 ° C. and is close to a saturated state, and the surface to be plated is cleaned to prevent generation of rust before plating.

In the plating process, for example, 440 to 470 ° C.
The manhole cover is immersed in a hot-dipped zinc bath or a hot-dipped zinc / 5% aluminum alloy bath, which is preferably repeated to form a plating film while checking that no unplated portion appears. Zinc / aluminum alloy plating is advantageous because of improved corrosion resistance. In the case of a zinc / 55% aluminum alloy bath, the bath temperature is set to about 600 ° C. If the spangles described later are not used as the pattern of the manhole cover, electrogalvanization may be used, and in this case, the above flux treatment can be omitted.

Immediately after plating, the manhole cover is cooled in the usual manner. In this cooling treatment, an alloy layer of iron and zinc is formed on the casting surface, and a zinc layer is formed on this metal layer.However, if cooling takes too long, the alloy layer grows too much and the zinc layer Becomes too thin, which causes problems with anticorrosion properties. On the other hand, when rapidly cooled, spangles (zinc crystal pattern) that appear on the plated surface are less likely to appear, which is disadvantageous in using this spangle as a surface pattern of a manhole cover. Therefore, in the cooling step after plating, it is desirable to immerse the manhole cover in warm water at 60 to 90 ° C. for 1 to 3 minutes, cool it, and then pull it up. However, spangles do not necessarily have to be positively exposed, and in those cases, a water-cooling method or an air-cooling method may be appropriately adopted instead of hot water cooling.

The manhole cover 1 after plating has a surface of the plating film 2 which is smooth, so that it is subjected to a film formation treatment in order to improve the adhesion to the coating film and to deluster the glitter of the plating film. , Chemical conversion film 3 on plating film 2
Are laminated. First of all, as a pretreatment, 50 to 7
Immerse it in a weak degreasing solution at 5 ° C for 1 to 10 minutes to clean it, then wash with water, and then add it to a colloidal titanic acid solution at 15 to 40 ° C (trade name: Prevaline Z manufactured by Nippon Parkerizing Co., Ltd.) to 0.5
Immerse and stir for ~ 1 minute to adjust the surface. Then, the manhole cover is immersed in a zinc phosphate bath at 50 to 80 ° C for 2 to 5 minutes to form a zinc phosphate conversion coating on the plating coating with a thickness of 5 to 3
A stack of 0 g / m ² is formed. The zinc phosphate conversion film thus obtained has excellent peel resistance and develops a gray color. In the case of a hot-dip zinc or hot-dip zinc alloy plating film, spangles appear on the plated surface and are visible through the chemical conversion film. Incidentally, the film chemical conversion treatment is preferably a phosphate film formed by zinc phosphate or iron phosphate,
It can also be chromated.

At least the outer surface of the manhole cover 1 exposed on the road surface is coated with a coating film 4 on the chemical conversion coating 3. As the coating film 4, the chemical conversion film 3 as shown in FIG.
It may be composed of only a clear coating film directly formed on the upper surface. In this case, zinc spangles grayed by zinc phosphate treatment can be directly used as an appearance pattern. The clear coating film in this case is a concept including a colored and transparent coating film. This clear paint includes acrylic-silicone paint which will be described later. However, the coating film 4 is a colored coating film (5) formed on the chemical conversion film 3 as shown in FIG.
6) and a clear coating film 7 laminated on the outer surface thereof. The colored coating film shown in FIG. 3 is composed of an undercoat coating film 5 and an intermediate coating film 6, but any one of these colored coating films (5.6) may be used.

The colored coating film (5, 6) is composed of an acrylic / silicone coating containing 3 to 15% by weight of whiskers such as potassium titanate and carbon for the purpose of enhancing coating strength such as impact resistance. It is also suitable for use in achieving good adhesion. The reason why the whiskers are mixed in an amount of 3 to 15% by weight is that if the amount is less than 3% by weight, the original coating film strength cannot be increased, and if it exceeds 15% by weight, problems arise in terms of adhesion. In any case, the clear coating film to be the top coat layer is formed of a transparent resin coating containing 1 to 30% by weight of a slip preventive material such as silica sand having a particle size of 2 to 3 μm or transparent silicon oxide such as silicic anhydride. Adds anti-slip performance in rainy weather. Silica acid containing silica sand is a typical example of the transparent anti-slip material, which contributes to increasing the strength (peeling resistance) of the coating film, but other materials may be used. The transparent anti-slip material is mixed in an amount of 1 to 30% by weight, because if it is less than 1% by weight, the original anti-slip function cannot be effectively exhibited.
This is because the coating film becomes brittle if it exceeds the weight percentage.

However, the coating film 4 does not necessarily have to be a clear coating film. In that case, the coating film 4 is formed with an opaque anti-slip coating, and an anti-slip layer may be laminated on the outer surface of the coating film 4. As the anti-slip coating in that case, a mixture of an organic polymer material with an anti-slip material such as zeolite or diatomaceous earth may be used, or a crosslinkable rubber or a thermoplastic rubber-like polymer, or a mixture thereof may be used. A coating material containing a copolymer such as isobutylene may be used.

[0016]

The iron manhole cover 1 of the present invention is excellent in corrosion resistance due to the synergistic action of the zinc or zinc alloy plating film 2 and the coating film 4. The surface of the chemical conversion film 3 is a fine uneven surface, and the adhesion of the coating film 4 thereafter is also good. When the chemical conversion film 3 is a zinc phosphate film in particular, spangles of zinc plating appear in a gray color, but when the clear coating film 4 is directly applied on the chemical conversion film 3, this clear coating A deep gray spangle looks like a marble pattern through the film 4, and the spangle can be used as it is as a surface pattern of the manhole cover 1.

When a colored coating film (5, 6) as the coating film 4 and then a clear coating film 7 are formed on the chemical conversion coating 3 in a laminated manner, the colored coating film can be colorfully colored as desired, so that the color pavement can be colored. You can get a manhole cover that matches the road. Furthermore, in any case, since the transparent anti-slip material is mixed in the clear coating film which becomes the top coat layer, there is an advantage that the anti-slip function when wet with rainwater can be effectively exhibited. Also, by mixing whiskers such as glass fibers into the undercoating film and the intermediate coating film, the coating film strength such as impact resistance can be achieved.

[0018]

【Example】

(Example 1) Shot blast treatment process: Cast iron manhole cover 1
Steel cast particles were repeatedly sprayed with a shot blast machine to remove cast sand and carbon deposits on the surface, iron oxide was also dropped, and the residual casting stress on the surface was also removed by impact. Pickling step: Next, the manhole lid was immersed in an 8% sulfuric acid aqueous solution heated to 40 ° C. for 3 minutes to remove iron oxide on the surface. The manhole cover was lifted from the acid bath and washed with water to check the pickling condition. Flux treatment step: The manhole cover 1 was immersed in an aqueous solution of zinc ammonium chloride close to a saturated state heated to 80 ° C. for 1 minute for flux treatment.

Plating process: Manhole cover 1 at 450 ° C.
It was immersed in the molten zinc bath of No. 1 and pulled up after 5 minutes. By repeating these three times, the plating film 2 having a thickness of 80 μm was formed on the outer surface of the manhole cover 1. Cooling process: The manhole cover 1 after plating is immediately heated to 68 ° C.
It was dipped in the warm water of 3 minutes and pulled up. Coating conversion treatment step: After cooling, after various pretreatments, the manhole cover 1 is dipped in a zinc phosphate bath at 68 ° C. for 3 minutes, and the zinc phosphate conversion coating 3 is laminated on the plating coating 2 to a thickness of 12 g / m ² . Formed.

Coating process: On the outer surface of the manhole cover 1 which has an uneven pattern on the road surface side, a transparent acrylic / silicone coating containing 5% by weight of silica sand having a particle size of 2 μm on the chemical conversion film 3 as an anti-slip material. Spray coating was performed, and a clear coating film 4 having a thickness of 50 μm was entirely laminated on the outer surface of the manhole cover 1 over the projections 1a and the depressions 1b. As the acrylic / silicone paint here, a curing agent (active alkoxysilane group) is added to a siloxane cross-linking reactive polymer, that is, a main agent (acrylic main chain), and after coating, moisture in the air is absorbed to form a siloxane bond. I used one.

Thus, the product of FIG. 2 was produced in which the galvanized coating 2, the chemical conversion coating 3, and the clear coating 4 were sequentially laminated on the outer surface of the iron manhole cover 1. When this happens,
A deep chemical conversion film 3 was visible through the clear coating film 4, zinc spangles (crystal patterns) became gray striped patterns, and a product manhole cover in which a marble-like pattern appeared was obtained. The clear coating film 4 on the surface exhibited a good anti-slip function.

(Embodiment 2) The protrusions 1a and the recesses 1b on the outer surface of the manhole cover 1 which has been subjected to a film conversion treatment after plating has a base color on the conversion film 3 as shown in FIG. The undercoat coating film 5 is formed by spray coating, and the intermediate coating film 6 of a different color is roller-coated on the undercoat coating film 5 only at the portion corresponding to the convex portion 1a. 1a intermediate coating film 6 and recess 1b undercoating film 5
A clear coating film 7 was spray-painted on the surface of No. 3, and a manhole cover was prepared in the same manner as in Example 1 except for the composition of the clear coating film 7. However, in order to secure coating strength including impact resistance, the undercoat coating 5 and the intermediate coating 6 were formed of acrylic / silicone-based paint containing 7% by weight of whiskers such as potassium titanate.

In this case, the undercoating film 5 and the intermediate coating film 6 constitute a colored coating film, and in the coating film 4 on the outer surface of the manhole cover 1, the clear coating film 7 is formed on the convex portion 1a.
The intermediate coating film 6 can be seen through, and the concave coating 1 can see the undercoat coating film 5 through the clear coating film 7. By selecting the colors of the undercoat coating film 5 and the intermediate coating film 6, different colors can be obtained. I was able to finish it colorfully.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of a manhole cover.

FIG. 2 is a schematic sectional view of a main part of the first embodiment.

FIG. 3 is a schematic cross-sectional view of a main part of the second embodiment.

[Explanation of symbols]

 1 Manhole cover 2 Plating film 3 Chemical conversion film 4 Coating film 5 Undercoat coating film 6 Intermediate coating film 7 Clear coating film

Front Page Continuation (72) Inventor Shingo Takamatsu 3-3-4 Kitakagaya, Suminoe-ku, Osaka City, Osaka Prefecture OEM Industry Co., Ltd. No. OM Industry Co., Ltd.

Claims (5)

[Claims] 1. A zinc or zinc alloy plating film 2 on the outer surface.
An iron manhole cover in which a chemical conversion film 3 and a coating film 4 are sequentially laminated. 2. The chemical conversion film 3 is a zinc phosphate film,
The iron manhole cover according to claim 1, wherein the coating film 4 is a clear coating film formed directly on the chemical conversion film 3. 3. The iron manhole cover according to claim 1, wherein the coating film 4 comprises a colored coating film formed on the chemical conversion coating 3 and a clear coating film formed on the colored coating film. 4. The iron manhole cover according to claim 2 or 3, wherein the clear coating film contains an anti-slip material. 5. The iron manhole cover according to claim 3 or 4, wherein the colored coating film is a coating film containing whiskers.