JPH05192634A - Surface protecting method - Google Patents

Abstract

PURPOSE:To provide a surface protecting method for forming a protective film excellent in adhesive strength, impact resistance and rust preventiveness on a surface to be protected. CONSTITUTION:An undercoat layer A of a polyacrylate resin binder contg. aggregate of <=0.3mm size, a two-layered coating film B of cement blended with a resin binder, a thickener and a fluidizing agent, a sealer layer C and a top layer D are successively formed on the surface of an iron plate X.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface protection method for iron plates, steel frames, aluminum plates, bridges, bridge piers, tanks, roofs, pipes, stairs, concrete surfaces and the like.

[0002]

2. Description of the Related Art As is well known, in order to prevent the occurrence of rust and damage, the surface is coated. Although the paint used for this coating has improved significantly in recent years, it has been developed from synthetic polymer resin solvent type to fluorine type, acrylic silicone type,
There are many types such as epoxy type and other reaction-curing type that is characterized by durability, but the coating thickness is thin and the thickness is about 0.1 mm or less. Therefore, the surface coating film is damaged by flying objects such as sand dust and reaches the iron surface, and rust grows from there. Thus, it is inferior in resistance to external stimuli such as impact and wear. Also, the organic solvent is
It is difficult to handle due to human body problems and flammability. Since it is an organic substance, it emits ultraviolet rays (sun rays), ozone, NOx. "Degradation of the coating film" and "solidification of the coating film" occur over time under the influence of SOx and the like. In general, as the colorant, an organic colorant is often used, and thus fading and discoloration are remarkable.
Therefore, the rust preventive effect also declines, and depending on external conditions, it may be 3-5
Rust is generated everywhere in the year, and repainting becomes necessary. In reality, the cost for repainting is higher than the initial painting cost including scaffolding and keren.

Further, conventionally, as a method for preventing rust on a steel surface and for preventing corrosion, rust prepared by mixing rust preventive materials such as lead compounds, chromium compounds and zinc powder with a spreading agent (binder) such as synthetic resin. The most commonly used coating is a stop paint. However, these are generally solvent-based and have many problems in terms of safety, resource saving, hygiene, and the like. Further, since the binder used is organic, the rust preventive effect also deteriorates, and depending on external conditions, rust occurs every 3 to 5 years and repainting becomes necessary. Further, since the film thickness is generally as thin as 0.1 mm or less, there may be a problem in wear resistance.

On the other hand, various rust preventive methods other than these organic rust preventive paints have been proposed and adopted. For example, iron pipes are coated with cement mortar to passivate the iron surface in an alkaline atmosphere of cement, but cement mortar alone does not have sufficient adhesion to the iron surface, and it does not dry. Its applications are remarkably limited due to the generation of cracks associated with shrinkage, lack of mechanical strength and impact resistance.
In order to improve these drawbacks, a rust preventive method is also applied in which a cement mortar is coated with a polymer cement mortar containing a synthetic resin emulsion compatible with the cement mortar on the iron surface. There is a problem in the property, air permeability, etc.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a surface protective layer which is excellent in adhesion and impact resistance, forms a strong coating film at room temperature, and has excellent rust-preventing power and surface protective power, quickly and inexpensively. It is an object of the present invention to provide a surface protection method that can be formed.

[0006]

The present invention has been made in order to solve the above-mentioned problems, and a plurality of materials are laminated by a spraying method or in combination with brush coating, and the characteristics of each material are utilized to It is a surface protection method characterized by forming protective layers that complement each other's defects. That is, the present invention is
A protective layer is formed only by a spraying method or in combination with brush coating, and the protective layer is an undercoat layer A, a coating layer B (polymer cement mortar layer), a sealer layer C and a top layer D.
In order to form the undercoat layer, a synthetic polymer emulsion (PAE) polyacrylic acid ester, a mixture of a cyclic fatty acid salt and an aggregate of about 0.3 mm or less is used as a main material, and a conventional method is used. Thickener, defoamer, dispersant,
In order to form the coating layer B by using a primer containing a pigment or the like, cement is mixed with a thickening agent, a fluidizing agent, an antifoaming agent, a fiber, a pigment aggregate, etc., and a synthetic polymer emulsion ( P
AE) polyacrylic acid ester composite material is used, the sealer layer C is formed by using a synthetic polymer emulsion (PAE) polyacrylic acid ester, and the top layer D
The acrylic synthetic polymer emulsion (clear) or the silicone acrylic paint is used for the formation.
The total coating thickness of four layers is preferably 1.7 mm or less and is about 1.3 mm after drying, and the resin solid content in the polymer cement mortar is preferably 5% or more.

[0007] Usually, only an inorganic fired pigment is used for coloring,
Do not use any organic type. Therefore, it cannot be said that it is full of vivid aesthetics. When aesthetics are required, a method of finishing is performed by using a silicone-acrylic type organic / inorganic composite resin paint (durability and stain resistance are comparable to those of fluororesin) as the top coat (top layer).

[0008]

The undercoat layer A is for rust prevention, has a strong adhesion to metal, concrete surface, etc., the cyclic fatty acid salt constituting the material used exerts a rust preventive effect, and the aggregate is used in the next step. The adhesion of the coating layer to be applied is improved. Coating layer B is 2
Forming a coating thickness of 1.2 to 1.6 mm by spraying once,
Synthetic polymer that takes advantage of the long-term strength and durability of cement used as a material, and has the drawbacks of cement such as bending strength, compactness, low shrinkage, waterproofness, adhesiveness, salt resistance, and rust resistance. The polymer covers it. The reason why the number of coating layers is two is not limited to spraying in the case of one layer, but pinholes are always generated in hydrated products, water vaporized substances, etc., which adversely affects rust prevention ability and the like. It is to give and to prevent it. Since the sealer layer C may have pinholes, pores, and capillaries remaining even if the coating layer B has two layers, a dense sealer layer C is formed thereon to improve waterproofness and rustproofness. Yes, O _z of this construction, in the water
A sealed tissue structure is formed that does not allow permeation of chlorine, chloride ions, or air to the skin. Further, the top layer D has a function of filling the pinhole generated in the sealer layer C itself and improving the stain resistance.

[0009]

EXAMPLE FIG. 1 shows an example of the present invention, in which X is an iron plate as a protected object, A is an undercoat layer, B is a coating layer, C is a sealer layer, and D is a top layer. The undercoat layer A (primer) is a coating layer formed by blending a synthetic polymer emulsion (PAE) polyacrylic acid ester with a cyclic fatty acid salt as a rust preventive agent for enhancing the rust preventive effect, and further spraying it in a later step. In order to improve the adhesive strength of B, an aggregate having a size of 0.3 mm or less is blended, and a thickener, a defoaming agent, a dispersant, a pigment, etc. are blended. Use a roller or the like. When the surface of the iron plate X is coated with this undercoat layer A, it is estimated from the results of a salt spray test that a rust preventive effect equivalent to about two years is obtained, and a strong adhesive force is exhibited.

The coating layer B is composed of a powder obtained by mixing a cement with a thickening agent, a fluidizing agent, a defoaming agent, fibers, a pigment, an aggregate and the like, and a synthetic polymer emulsion (PAE) polyacrylic ester. Is a layer formed by spraying the polymer cement-based composite material, which has a coating thickness of 1.2-
The coating thickness is 1.6 mm. This coating layer B takes advantage of the long-term strength and durability of cement, and imparts the drawbacks of cement such as bending strength, compactness, waterproofness, adhesiveness, salt-proofness, and rust-proofness with a synthetic polymer. It was done. In the examples, the two times of spraying is not limited to spraying and coating, but hydrated products, water vaporized products and the like always generate pinholes, which have a significant adverse effect on rust prevention, etc. It is sprayed twice to form two layers. When the first spray is applied to form the coating layer B after drying the undercoat layer A,
Usually pinholes occur. However, if two layers are formed by spraying twice, it is extremely unlikely that the pinholes will overlap directly above the pinholes, and the pinholes in the first layer will be filled up, so there is a risk of rusting due to the pinholes. Disappears.

The sealer layer C is formed by spraying or brushing using a synthetic polymer emulsion (PAE) polyacrylic acid ester. The coating layer B has pinholes, pores,
Since there are some capillaries, the sealer layer C is formed to form a dense coating film and improve the waterproof property and the rust preventive property. By taking the method to fill impregnated with such resins to the pin hole or the like, the O _z or chlorine ions or air in the water to form a sealed tissue structures impervious to iron surface.

The top layer D is formed by spraying, and as the material thereof, one of the following two materials is used. Acrylic synthetic polymer Emuljun (Clear) Silicon acrylic paint The top layer D fills the pinholes generated in the sealer layer C and improves the stain resistance. For coloring the protective layer according to the present invention,
Normally, only inorganic calcined pigments are used and no organic pigments are used. Therefore, it cannot be said that it is full of vivid aesthetics. Therefore, when aesthetics are required, a method of overcoating with a silicone-acrylic (organic / inorganic composite resin) paint (durability and stain resistance are comparable to those of fluororesin) is used. The total coating thickness of the protective layer formed on the surface of the iron plate X is 1.5 to 1.7 mm, and the coating thickness after drying is substantially 1.3 to.
Excellent durability and long-term rust prevention by using a synthetic polymer emulsion (PAE) polyacrylic acid ester to be used and a resin solid content of 5% or more in the polymer cement mortar. It became an inorganic surface protective layer which has a sexual effect and is resistant to external impacts and stimuli such as abrasion. As described above, the present invention uses the spraying method in order to make use of the material characteristics (advantages) of forming each layer by laminating a plurality of materials, to use a laminating recipe to make up for the defects, and to increase the work efficiency. Moreover, the feature is that it enables chasing and stacking work.

Next, materials used in the examples of the present invention and test results will be described. The test results are obtained by observing and investigating the change in the rusting condition with time due to salt spray when the construction process was changed from one-layer finish to four-layer finish. The raw materials constituting the primer A in the examples of the present invention and the blending examples thereof are shown in Table 1. In addition, these raw materials and compounding examples were prepared by selecting raw materials and studying appropriate compounding so that the adhesion to the iron plate and the rust preventive power could be maximized.

[Table 1] Table 2 shows the blending of the raw materials constituting the coating layer B and the mixing conditions thereof in the examples of the present invention. Note that these raw materials and compounding examples were prepared by selecting the raw materials that can best exhibit long-term strength, durability, bending strength, compactness, adhesiveness, and impact resistance, and investigating appropriate compounding. ..

[Table 2]

[Salt water spray test method] The test body is hung in a humidity box with a temperature of 40 ° C and a humidity of 100%, and a mixture of 3% saline solution and 1% sodium sulfate water is sprayed from a humidifier to check the rust condition over time. The change was observed. (Implementation for 3 months) The method for molding the specimen of this example is shown below.

[Outer 1] The test results of the examples of the present invention are shown in Table 3.

[Table 3] Rust generation was confirmed in all of the ones having the process shortened from one layer to three layers. No rusting was observed on the four-layered test body. NO. As with 4 samples, when 3 layers were stopped (3 layers finish), the sealer had tack, and the spray finish was slightly uneven, so dust and the like adhered to it, and it was contaminated considerably and construction failed. I got it. Also, 100 ° C
When steam was sprayed from the heating of No. 3, blisters were observed in the sealer part in the three-layer finish, but no generation was observed in the four-layer finish. Thus, the step of applying the top as the stain resistant sealer on the fourth layer is important. Also, coating layer B
An attempt was made to simplify the process by finishing with only the top layer D (acrylic, silicon acrylic) on the top, but it was also found that the anticorrosiveness was poor. In terms of formulation, cracking occurred when the amount of cement was large, and it became noticeable when it was applied thickly.
Also, if fibers are not mixed in, they will sag, and thick coating requires fibers. The aggregate was made to have a continuous grain size to reduce the space. Also, when the resin solid content of the synthetic polymer emulsion was 5% or less, 1% and 3%, there was rusting and no rustproofing ability was obtained, but it was confirmed that 5% contributes to rustproofing ability. Was done. Further, the spraying work was good up to about 5% to 7%, but was not sprayed between 7% and 10% because the synthetic polymer emulsion became extremely thick. In this way, by using multiple materials and stacking, by utilizing the material characteristics (advantages) of forming each layer, a stacking recipe that compensates for defects is used, and in order to improve work efficiency, chasing lamination is performed. Construction (interval of each process (1) After spraying primer, interval time: 30 minutes, (2) 1st spray of mixture, 2nd spray of chasing mixture in a dry condition, 2nd interval: 2 hours, (3) It was found that the interval time after blowing the sealer: 1 hour, (4) Top spraying) is possible. Next, the rusting state when the type of emulsion and the resin solid content are changed will be described. Table 4 shows the rusting situation over time due to salt spray when the type of emulsion, acrylic type, EVA type, vibeova vinegar type, and resin solid content were changed to 1, 3, 5 (%). The changes were observed and examined. For comparison, the case of a primer (without rust preventive, containing rust preventive) and a general commercially available three-layer paint is also shown. The powder mixture of the mixture, the kneading condition, the spraying method and the primer treatment method, the salt spray test method, the specimen forming method and the curing time are the same as those described above.

[Table 4] As shown in the test results, the acrylic solid emulsion for comparison, the EVA emulsion for comparison, the vibeoba vinegar emulsion for comparison, and the resin solid content of 1 in the formulation of the present invention were used.
%, 3%, no rust preventive agent, only a primer containing a rust preventive agent, and rust was confirmed in all of the commercially available three-layer paints. Further, when the resin solid content of the synthetic polymer emulsion was 5% or less, 1% and 3%, rust occurred and no rust preventive effect was obtained, but when it was 5%, it was confirmed that the rust preventive effect contributed. It was Further, the spraying work was good at about 5% to 7%, but was not sprayed at 7% to 10% because the synthetic polymer emulsion became extremely thick. Thus, by using (PAE) polyacrylic acid ester as the synthetic polymer emulsion and setting the resin solid content in the polymer cement mortar to be 5% or more, excellent durability and long-term rust preventive effect are exhibited. Proved to be the most suitable material for.

Next, the test results regarding the rusting condition and the adhesion strength after repeated immersion in warm water and outdoor exposure will be described. In this test, the coating thickness of the coating layer B of the present invention is 0.5 mm, 1.0 mm, 1.5 mm, 2.5 mm,
The rusting condition and adhesion strength after repeated immersion in warm water and outdoor exposure in the case of changing to 3.0 mm were examined, and the results are shown in Table 5. 2 in warm water (90 ° C)
After immersion in warm water for 4 hours, outdoor exposure for 24 hours was repeated for 6 months, and the rusting condition of the surface of the test body was observed. However,
The adhesion strength test and the drop test were conducted 5 months after the start of the test. Regarding the drop test conditions, the state of the coating film when the test body was dropped onto the concrete floor 20 times from a height of 1 m was confirmed. Table 6 shows the test results. The powder composition of the coating layer B, the kneading conditions, the construction method by spraying and the primer treatment method are the same as those described above. Thickness of normal iron plate of test plate (80 × 160 × 1mm) 1mm
It usually takes about 10 years for the steel plate to collapse due to rust if left outdoors. 5 to 6 years outdoors under high humidity (without NaCl)
It takes about a year. High humidity (95% or higher), NaCl during the day and night
It takes 6 months under spraying. Repeating the high temperature (100 ° C. or less) high humidity to normal temperature drying requires 6 months. High temperature (less than 100 ° C.), high humidity to normal temperature, and repetition in the presence of NaCl require 3 months.

[Table 5]

[Table 6] In the above test example, rusting was confirmed at the coating thicknesses of 0.5 mm and 1.0 mm after about 4 months and 5 months. Also, above that, no rust was seen on the surface of the coating film, and the iron surface on the back side broke,
It was confirmed that there was biting into the edges. As a result, the coating thickness was set to about 1.5 mm in view of economy, workability and physical properties. Even after the iron broke in 6 months, no rust was found on the surface of the coating film. It is estimated that the coating film has a rust preventive power of about 10 years. .. Table 7 shows a comparison of various characteristics between the above-mentioned embodiment of the present invention and the cement mortar (comparative example) having an ordinary Portland cement / Toyoura standard sand = 1/3 and a water-cement ratio of 85%.

[Table 7]

[0015]

EFFECT OF THE INVENTION The rust-preventive effect of commonly used paints varies depending on external conditions, but rust occurs every 3 to 5 years, and repainting is required. The rust preventive power by the laminated coating film method of the present invention has been for 10 years,
~ 3 times more rustproof effect is obtained. 1 to repaint cycle
You can omit it twice. As for the cost for repainting, about 15% of the total cost is material and construction cost, and 85% is scaffolding and keren cost, and it is actually more than the initial coating cost. The above costs are reduced. According to a survey by the Japan Anticorrosion Technology Association, about 5% of GNP is required for rust prevention.
% There is a statistics that 2.5 trillion yen is used for one year, and according to Professor Masuko, the University of Tokyo, it is calculated that 1 ton per minute, 500,000 ton of iron is rusted annually. There is. As a result, it is a great merit that the repainting cycle can be omitted once or twice. As described above, the surface protection method according to the present invention has a strong adhesion to the object to be protected, excellent durability and impact resistance, and has an effect of having a long-term rust preventive effect.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

[Explanation of symbols] X Iron plate A Undercoat layer B Coating layer C Sealer layer D Top layer

Claims (3)

[Claims] 1. A subbing layer A made of a binder resin containing an aggregate having a size of 0.3 mm or less on a surface to be protected, and a coating layer B made of cement mixed with a binder resin, a thickener and a fluidizing agent. , A sealer layer C and a top layer D are sequentially formed, which is a surface protection method. 2. The surface protection method according to claim 1, wherein the coating layer B has two layers. 3. The surface protection method according to claim 1, wherein polyacrylic acid ester is used as the binder resin.