JPS6141262B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an anticorrosion coating method for forming a coating layer that has long-term weather resistance and anticorrosion properties and has excellent interlayer adhesion. Traditionally, to protect steel structures from corrosive environments,
It was common practice to apply a primer such as an oil-based anti-corrosion paint, a synthetic resin anti-rust paint, or a zinc-rich paint, and then coat it with various synthetic resin paints. However, resin coating (lining) has come to be used in locations with extremely severe corrosive environments or where longer-term corrosion protection is required. For example, it has come to be used mainly in various pollution prevention devices and chemical equipment, as well as tanks, oil tanks of ships, and the bottoms of ships. The resin used for these resin linings is unsaturated polyester resin due to its room-temperature curability, on-site workability, and cost.The lining method is FRP lining, in which organic filtration is added to the resin in advance before lining construction. It was common practice to mix oxides, apply a sheet-like base material made of glass fiber to the base material to be lined, impregnate the resin using a felt roll, etc., simultaneously defoam it, and harden it. . Recently, in addition to this method, there is a method (flake lining) in which a composition made by blending extremely thin glass flakes with resin instead of glass fiber is applied to the object to be coated with a trowel. It has been put into practical use. For example, the above-mentioned compositions include a protective and decorative coating composition containing fine glass flakes in an organic resin binder vehicle (Japanese Patent Publication No. 51-25368), or a coating composition containing fine glass flakes in a lining resin as a corrosion-resistant material. Lining material filled with glass flakes and glass fibers as reinforcing material
30855), and by treating the surface of flaky glass with an appropriate substance, it can be given hydrophobicity and leafing properties, and plastics, paints, insulating paper, etc. filled with this can be made. (Tokuko Showa 47
-16821) is also known. Considering the various performance aspects of the coating, all of the above compositions are applied to ultra-thick films of 2 mm or more, and the construction cost is also very high.Therefore, they are not widely applied to general steel structures, and the above Currently, it is used for very limited special purposes. If flake lining, which is currently used as a lining material, was used in a thin film of 2 mm or less in consideration of cost, it would not be possible to obtain the desired coating performance and would not be practical. In particular, when used as a thin film, rust was generated from pinholes in the film, which was a serious problem. In other words, rust that occurs in the pinhole area grows rapidly, and rust does not only occur in the pinhole area, but also progresses from that area between the coating and the base steel, and eventually leads to large defects such as blistering and peeling of the coating. It becomes. In addition, when used for bridges, offshore structures, etc., it is necessary to color the object to match the purpose of the object, so it is necessary to use the above-mentioned lining material mixed with colored pigments, or to use the above-mentioned After the lining material is applied, a top coat of urethane, acrylic, or chlorinated rubber paint is applied. However, films made from ordinary colored pigments change color or fade after long-term use, so they cannot be used as lining materials in applications where a durability of 20 to 30 years, and in some cases 50 to 60 years, is required. During that period, the surface had to be repainted several times. On the other hand, as steel structures such as bridges and tanks become larger, the cost and man-hours required for repainting tend to increase. The demand for long-lasting coating systems has become very strong. Generally, in the corrosion reaction of painted steel structures in a neutral environment such as in the atmosphere, the oxygen reduction reaction dominates the cathodic reaction during corrosion, so the amount of oxygen permeation through the paint film is considered to be a problem. It is considered. When considering the dominance of the cathode reaction in corrosion due to oxygen reduction reaction, the critical current density (Imax), which corresponds to the corrosion rate of steel under the coating film, is expressed by the following equation. Imax=Mmax・n・F=K・Co・nF/d [Mmax: Amount of diffused dissolved oxygen K: Oxygen diffusion coefficient d: Thickness of diffusion layer (coating film thickness) n: Number of reaction electrons F: Faraday constant Co: [Oxygen concentration] Therefore, in order to reduce the corrosion rate of steel under a coating film, it is necessary to make the film very thick or, if the film thickness is constant, to reduce the amount of diffused dissolved oxygen or the oxygen diffusion coefficient, that is, the amount of oxygen permeation. It is necessary to reduce the It is also necessary to suppress the reduction in film thickness due to yoking or the like for a long period of time. If the amount of oxygen permeation through the paint film is halved, the corrosion rate of the steel under the paint film will also be halved, and therefore the oxygen permeability of the paint film is extremely important for the long-term corrosion protection of painted steel structures. It becomes a factor. However, the acrylic resin and chlorinated rubber used as color vehicles in the above-mentioned top coat paints are
Since the oxygen permeability is relatively high, corrosion of the steel under the paint film is accelerated and paint film defects are likely to occur.In addition, the resin and pigment of the top coat paint are easily deteriorated by ultraviolet rays, etc., resulting in discoloration, chalking, and cracking. This causes a decrease in gloss and fading of color. Therefore, long-term corrosion resistance and weather resistance could not be expected at all. Recently, silicone resin has been developed as a resin with good weather resistance, and attempts are being made to apply it to top coats. However, silicone alkyd resins and silicone acrylic resins that dry at room temperature have relatively high oxygen permeability, so even if the weather resistance of the top coat film improves somewhat,
The effect of suppressing the corrosion of steel under the coating film could not be expected, and the top coating film was soft and easily stained and scratched, while at the same time the resin whitened. Also,
Even though the above resin does not deteriorate over a long period of time and has luster,
The pigment on the surface layer of the coating fades and the color changes greatly from its initial color, so it cannot withstand long-term use. In addition, conventional top coat paints generally have poor adhesion to the lining film and have the disadvantage of peeling between layers in a short period of time. The present invention aims to eliminate all the drawbacks of the prior art as described above, and provides a corrosion-resistant coating method for obtaining a coating that has long-term corrosion resistance and weather resistance, as well as excellent interlayer adhesion. That is. That is, the present invention includes (a) a step of applying an anti-corrosion lining material on the object to be coated and drying it at room temperature; A top coat containing a fluorine-containing copolymer consisting of 5 to 45 mol% of vinyl ether, 3 to 15 mol% of hydroxyalkyl vinyl ether, and 0 to 30 mol% of other comonomers, and (b) a polyvalent isocyanate. This relates to an anti-corrosion coating method comprising the steps of applying and drying at room temperature to form a top coat. The anticorrosive lining material used in the anticorrosive coating method of the present invention is preferably a composition obtained by mixing an unsaturated polyester resin, epoxy resin, or the like with a flat pigment, a hardening agent, and the like. The unsaturated polyester resin is suitably a resin that is liquid at room temperature without being diluted with a volatile solvent, and that is cured by a curing agent or a catalyst, so that the cured coating film has excellent water resistance and chemical resistance. Examples of these resins include generally commercially available isophthalic acid-based unsaturated polyester resins, bisphenol-based unsaturated polyester resins, and epoxy acrylate resins. Examples of the unsaturated polyester resin include, for example, U-Pica 5523 and 4529, manufactured by Nippon U-Pica Co., Ltd., which are generally commercially available as isophthalic acid-based unsaturated polyester resins, and Rigorac 150HR, manufactured by Showa Kobunshi Co., Ltd. ：Product name: Atlas 382-05, manufactured by Kao Atlas Co., Ltd., which is generally commercially available as a bisphenol-based unsaturated polyester resin:
Product name Rigoratsuku LP-1 manufactured by Showa Kobunshi Co., Ltd.:
Nippon U-Pica Co., Ltd.'s product name: U-Pica 5834, etc.: Kao Atlas Co., Ltd.'s product name: ATLATSUKU G-, which is generally commercially available as an epoxy acrylate resin.
6575: Showa Kobunshi Co., Ltd. product name Lipoxy R-
800: Product name Neopol manufactured by Nippon U-Pica Co., Ltd.
8250: Dainippon Ink and Chemicals Co., Ltd., trade name Deitzkrite 3505: Dow Chemical Co., Ltd. trade names Delacane 510 and 411. These resins are commercially available, usually containing 10 to 50% by weight of a liquid α/β-monoethylenically unsaturated monomer such as styrene or methyl methacrylate. Therefore, in the present invention, the unsaturated polyester resin includes monomers thereof. The epoxy resin used in the present invention has two or more epoxy groups in its molecule, usually located at both ends of the molecule, and is one commonly used for paints. As the epoxy resin, for example, as a bisphenol type epoxy resin, Epicoat, a commercially available product manufactured by Ciel Chemical Co., Ltd., is a commercially available product.
828, 834, 836, 1001, 1004, DX-
255: Product name manufactured by Ciba Geigy Corporation Araldite GY-260: Product name manufactured by Dow Chemical Corporation
DER330, 331, 337: Trade name Epicron 800, manufactured by Dainippon Ink and Chemicals Co., Ltd.: Trade name DEN431, manufactured by Dow Chemical Co., Ltd., which is generally commercially available as a phenol novolak type epoxy resin.
438: As a polyglycol type epoxy resin,
Commercially available Araldite CT-508 manufactured by Ciba Geigy Co., Ltd.; DER-732 and DER-736 manufactured by Dow Chemical Co., Ltd.; commercially available ester-type epoxy resins such as those manufactured by Dainippon Ink and Chemicals Co., Ltd.; Trade names Epicron 200 and Epiclon 400; examples of linear aliphatic epoxy resins include epoxidized polybutadiene such as BF-1000 manufactured by Nippon Soda Co., Ltd. Furthermore, epoxy compounds that are easily analogous to these resins and derivatives of the above-mentioned epoxy resins can be similarly used and are included within the technical scope of the present invention. Examples include polyol type epoxy resins, alicyclic epoxy resins, halogen-containing epoxy resins, and the like. The flat pigments preferably used in the lining material are inorganic, extremely thin flat particles with a thickness of 0.5 to 10 microns and a size (maximum length) of 0.05 to 6 mm, and representative examples include flake glass and mica powder. etc. Particularly preferred is flake glass. When the mixture of the flat pigment and the resin is applied to a material, in the coating film that is formed, the flat pigment is laminated in many layers parallel to the material,
Permeation of corrosive materials such as steam, moisture, and salt from the outside;
Shows the effect of preventing penetration. Generally, the effect is greater as the thickness of the flat pigment is thinner and the diameter is larger.
On the other hand, the smaller the diameter, the better the workability in coating the surface. Therefore, in terms of both performance and workability, the size is
A flat pigment of about 0.1 to 3 mm is most preferred. In the present invention, the action of the flat pigment in the flake lining material and the low oxygen permeability of the top coat, which will be described later, combine to protect the coated object for a long period of time. Furthermore, the mixing ratio of the flat pigment to the resin component also affects the corrosion resistance, physical properties of the film, and workability. The mixing ratio of the flat pigment to the resin component is 10 to 150 parts by weight, preferably 15 to 100 parts by weight, per 100 parts by weight of the resin component. If the amount of the flat pigment mixed is less than the 10 parts by weight, the effect of inhibiting the permeation of corrosive materials such as moisture will drop sharply, and if it exceeds 150 parts by weight, the lining film tends to become brittle. When the lining material is used, a curing agent, a curing accelerator, etc. are used together with it in a conventional manner. As the curing agent for the unsaturated polyester resin, common peroxides and the like are used. The peroxide is preferably ketone peroxide, hydroperoxide, or peroxy ester. As the ketone peroxide, methyl ethyl ketone peroxide is suitable. Further, as the hydroperoxide, t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, paramenthane hydroperoxide,
Examples include 2,5-dimethyl-2,5-dihydroperoxyhexane, and use of cumene hydroperoxide and t-butyl hydroperoxide is particularly preferred. These may be used alone or as a mixture of two or more. Furthermore, as peroxy esters, t-butyl peroxy phthalate, t-butyl peroxybenzoate, t-
Examples include butyl peroxylaurate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy pivalate, t-butyl peroxy acetate, t-butyl peroxy isobutyrate, and especially t-butyl peroxy Preference is given to using peroxyphthalate and t-butyl peroxylaurate. These may be used alone or as a mixture of two or more. The peroxide is about 0.1 to 100 parts by weight of unsaturated polyester resin solid content (including styrene, etc.)
It is added in a proportion of 3 parts by weight. Furthermore, as the curing agent for the epoxy resin, those commonly used for paints, such as amine adduct and polyamide resin, can be used. An example of the curing agent is Tomide Y-, a commercially available polyamide resin manufactured by Fuji Kasei Kogyo Co., Ltd.
25, 245, 2400, 2500: Daiichi General Co., Ltd. product names: Xenamide 2000, Versamide 115,
125: Sanwa Chemical Co., Ltd., product name Sanmide 320, same
330, X2000: Trade name Epicure 3255, 4255 manufactured by Ciel Chemical Co., Ltd.; Tomide 238, manufactured by Fuji Kasei Kogyo Co., Ltd. as amine adduct resin.
Fujikiure 202: Asahi Denka Co., Ltd.'s product name: Adeka Hardener EH-531; Sanwa Chemical Co., Ltd.'s product name: Sanmide T-100 and D as aliphatic polyamines
-100, P-100; Epomate B-002, manufactured by Ajinomoto Co., Inc. as a heterocyclic diamine derivative, C-
002 and S-005. The amount of the curing agent added to the epoxy resin is around the equivalent, that is, 0.7 to 1.3 per equivalent of the epoxy resin.
It is in the equivalent range. Furthermore, extender pigments, anti-settling agents, dispersants, diluents, solvents and other flat pigments can be added to the lining material, if necessary. Furthermore, the fluorine-containing copolymer as the top coating used in the coating method of the present invention contains fluoroolefin, cyclohexyl vinyl ether, alkyl vinyl ether, and hydroxyalkyl vinyl ether as essential constituents, respectively, in amounts of 40 to 60 mol% and 5 to 45 mol%, respectively. mol% and proportions from 3 to 15 mol%,
It is important that the content is preferably 45 to 55 mol%, 10 to 30 mol%, 10 to 35 mol%, and 5 to 13 mol%, respectively. Too low a fluoroolefin content is not only unfavorable from the viewpoint of weather resistance, but also causes problems in production. Also, those containing too high a fluorofrefine content are also difficult to manufacture. On the other hand, if the cyclohexyl vinyl ether content is too low, the hardness when formed into a coating film is undesirable, and if the alkyl vinyl ether content is too low, the flexibility is undesirable. The fluorine-containing copolymer used in the coating method of the present invention should contain hydroxyalkyl vinyl ether in a proportion within the above range, so that it can be cured without impairing various useful properties as a paint base. This is particularly important from the perspective of improving
In other words, if the hydroxyalkyl vinyl ether content is too high, the solubility of the copolymer will change and it will only dissolve in certain substances such as alcohols, which will only limit its applicability as a solution-type paint base. This is undesirable because it reduces the flexibility of the cured coating film and reduces the gelation time (pot life) in the presence of the curing agent, significantly impairing the workability of the coating material. In addition, if the content is too low, the effect of improving curability will be lost, resulting in an increase in curing time, a decrease in solvent resistance, stain resistance, etc. of the cured coating film, and furthermore, the adhesion with the lining material will be reduced. This is not preferable because it causes disadvantages such as damage. In the fluorine-containing copolymer, perhaloolefin, particularly chlorotrifluoroethylene or tetrafluoroethylene, is preferably employed as the fluoroolefin. Moreover, as the alkyl vinyl ether, those containing a linear or branched alkyl group having 2 to 8 carbon atoms, particularly those in which the alkyl group has 2 to 4 carbon atoms, are preferably employed. Note that the fluoroolefin and the alkyl vinyl ether are not limited to being used alone, but may also be used in the form of a mixture of two or more types. The fluorine-containing copolymer may contain units based on comonomers other than the above four essential components in an amount not exceeding 30 mol %. Such comonomers include olefins such as ethylene, propylene, and isobutylene, haloolefins such as vinyl chloride and vinylidene chloride, unsaturated carboxylic acid esters such as methyl methacrylate, vinyl acetate, vinyl n-butyrate, etc. Examples include vinyl carboxylates. As the fluorine-containing copolymer, one having an intrinsic viscosity of about 0.05 to 2.0 dl/g, particularly about 0.07 to 0.8 dl/g, as measured in an uncured state in tetrahydrofuran at 30°C, can be preferably employed. . If the viscosity is too low, the mechanical strength will decrease, while if it is too high, when applied as a solution-type paint, the solution concentration will have to be lowered due to the viscosity, and the workability will be impaired. Both are undesirable. The above-mentioned fluorine-containing copolymers are prepared by adding a polymerization initiator such as a water-soluble initiator or an oil-soluble initiator or ionizing radiation to a monomer mixture in a predetermined proportion in the presence or absence of a polymerization medium. It can be produced by causing a copolymerization reaction by applying a polymerization initiation source. When using the thus obtained fluorine-containing copolymer as a top coating, various solvents can be used, including aromatic hydrocarbons such as xylene and toluene, alcohols such as n-butanol, In addition to esters such as butyl acetate, ketones such as methyl isobutyl ketone, glycol ethers such as ethyl cellosolve, etc.
Various commercially available thinners can also be used. Mixing of the copolymer and the solvent can be carried out using various equipment commonly used for forming paints, such as a ball mill, a paint shaker, a sand mill, a jet mill, a three-roll mill, a kneader, and the like. At this time, organic pigments, inorganic pigments (including fired pigments, extender pigments, metal pigments, etc.), dispersion stabilizers, viscosity modifiers, leveling agents, anti-gelling agents, ultraviolet absorbers, etc. can also be added. In the coating method of the present invention, a polyvalent isocyanate is mixed into the fluorine-containing copolymer solution obtained as described above or a dispersion in which a pigment, etc. is dispersed, and then applied. The polyvalent isocyanate is a polyvalent isocyanate having two or more isocyanate groups in one molecule, for example, ethylene diisocyanate,
Propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, decamethylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1.
5-Naphthylene diisocyanate, 4.4'.
4″-Triphenylmethane triisocyanate,
4,4'-diphenylmethane-diisocyanate,
Polyvalent isocyanates such as 3,3'-dimethyl-4,4'-diphenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, isophorone diisocyanate, lysine isocyanate, and an excess of the above-mentioned isocyanate compounds, for example, ethylene glycol, Propylene glycol, 1,3-butylene glycol, neopentyl glycol, 2,2,4-trimethyl-1,3-pentanediol, hexamethylene glycol, cyclohexanedimethanol,
trimethylolpropane, hexanetriol,
Examples include polyvalent isocyanates having two or more functionalities obtained by addition reaction with low-molecular-weight polyols such as glycerin and pentaerythritol, polyvalent isocyanates having a Biuret structure, and polyvalent isocyanates having an allophanate bond. Among the polyvalent isocyanates, non-yellowing diisocyanates such as hexamethylene diisocyanate and isophorone diisocyanate and adducts thereof are particularly useful. The mixing ratio of the fluorine-containing copolymer and the polyvalent isocyanate is (hydroxyl groups in the fluorine-containing copolymer)/
(Isocyanate group in polyvalent isocyanate)=
The range of 1/1.3 to 1/0.5 (equivalent ratio) is preferable. In addition, in order to promote the reaction between the fluorine-containing copolymer and the polyvalent isocyanate, it is also possible to add a known catalyst such as dibutyltin dilaurate. In the anticorrosion coating method of the present invention, first, the anticorrosion lining material is applied onto the object to be coated by a conventional method such as brushing, roller, spraying, etc. to a dry film thickness of 2 mm or less, preferably 300 microns or more. , dried at room temperature. Therefore, the objects to be coated that are the object of the present invention include iron, iron,
It is a metal such as zinc plating, and the metal may be coated with a rust-preventing primer such as an unsaturated polyester primer, a zinc-rich paint, or an epoxy primer, if necessary. Furthermore, after coating and drying the anticorrosive lining material, it is also possible to apply a binder coat using an epoxy resin, chlorinated rubber, vinyl resin, or allyl ether resin as a color vehicle. Then, apply the top coat with a brush, roller,
Apply by spraying to a dry film thickness of 10 to 100 microns and finish by drying at room temperature. Thus, the coating layer obtained by the method of the present invention has extremely low permeability to oxygen, which is one of the corrosion factors, so it maintains corrosion resistance for a very long period of time, prevents corrosion of the coated object, and has a long-term lifespan. Because it has excellent weather resistance and also has very good interlayer adhesion, the interval between repainting is longer than would be possible with conventional coating systems, and the cost and man-hours required for repainting can be significantly reduced. Hereinafter, the details of the present invention will be explained with reference to Examples.
"Part" or "%" indicates "part by weight" or "% by weight". First, prior to the Examples, anticorrosive lining materials, top coats, etc. were prepared in the following manner. Preparation of anti-corrosion lining material [Formulation 1] (Main ingredient) 50 parts of isophthalic acid-based unsaturated polyester resin Organic bentonite (anti-settling agent) 3.5 Silane coupling agent 0.1 Styrene 25.7 Cobalt naphthenate (contains 6% metallic cobalt)
0.7 Glass flakes 20 (hardening agent) Methyl ethyl ketone peroxide 0.7 The unsaturated polyester resin is Rigorac 150HR (trade name, manufactured by Showa Kobunshi Co., Ltd.), and the organic bentonite is Benton (trade name, manufactured by National Red Co., Ltd.).
#34 and the silane coupling agent are from Shin-Etsu Chemical Co., Ltd.
The glass flakes used were KBM #503 (gamma-methacryloxypropyltrimethoxysilane) manufactured by Nippon Glass Fiber Co., Ltd. under the trade name CF-150. The base agent and curing agent are mixed at the time of use. [Formulation 2] (Main ingredient) Bisphenolic unsaturated polyester resin
55 parts Organic bentonite (same as formulation 1) 3.5 Silane coupling agent 0.15 Styrene 17.55 Cobalt naphthenate (same as formulation 1) 0.8 Glass flakes 23 (hardening agent) Methyl ethyl ketone peroxide 0.6 The unsaturated polyester resin was manufactured by Showa Kobunshi Co., Ltd. ) product name: Rigoratsuku LP-1, and the silane coupling agent is product name: KBM#403 from Shin-Etsu Chemical Co., Ltd.
[γ-glycidoxypropylmethoxysilane]
The glass flakes were manufactured by Nippon Glass Fiber Co., Ltd. under the trade name CF325. The base agent and curing agent are mixed at the time of use. [Formulation 3] (Main ingredient) Epoxy acrylate resin 70 parts Asbestos powder 1.5 Silane coupling agent (same as Formulation 1) 1 Cobalt naphthenate (Same as Formulation 1) 0.4 Mica 30 (Curing agent) Methyl ethyl ketone peroxide 1.2 The above epoxy acrylate resin The asbestos powder is manufactured by Showa Kobunshi Co., Ltd. under the trade name Ripoxy R-800, and the asbestos powder is manufactured by Union Carbide under the trade name Asbestos.
RG244 was used, and the mica was Suzolite Mica 60S manufactured by Kuraray Co., Ltd., respectively. The base agent and curing agent are mixed at the time of use. [Formulation 4] (Main ingredient) Bisphenol type epoxy resin 45 parts Glass flakes 30 Anti-settling agent (organic bentonite) 2 Methyl isobutyl ketone 10 Xylol 13 (Curing agent) Polyamide resin 75 parts Isobutanol 25 The above epoxy resin is manufactured by Ciel Chemical Co., Ltd. The product name is Epicoat 828 (epoxy equivalent: 184-194), and the glass flake is the product name CF- manufactured by Nippon Glass Fiber Co., Ltd.
48 and the polyamide resin Tomide #245 (active hydrogen equivalent: 90) manufactured by Fuji Kasei Kogyo Co., Ltd. were used. Mix the epoxy resin in the main ingredient and the anti-settling agent,
After kneading with a roller, other ingredients were added and stirred with a disper to create a base ingredient. At the time of use, 20 parts by weight of curing agent are mixed with 80 parts by weight of the base resin. Preparation of topcoat paint [Formulation 5] Contains units based on chlorotrifluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether, and hydroxybutyl vinyl ether in proportions of 51.2 mol%, 17.1 mol%, 22.5 mol%, and 9.1 mol%, respectively, and has an intrinsic viscosity of (at 30°C in tetrahydrofuran) ([η]) is 0.21 dl/g, glass transition temperature (DSC under 10°C/m heating) (Tg) is 45°C
100 parts of the fluorine-containing quaternary copolymer is mixed with 40 parts of xylene.
1 part, methyl isobutyl ketone in a mixed solvent of 120 parts, add 42 parts of titanium oxide, and boil in a pot mill.
The mixture was kneaded for 24 hours to obtain a main ingredient. Add to this 8 parts of hexamethylene diisocyanate as a curing agent, and 15 x 10 ^-7 dibutyltin dilaurate.
The components were mixed at the time of use to obtain a top coat [Formulation 5]. [Formulation 6] 50.8 mol%, 16.9 mol%, 22.8 mol% and 9.5 mol% of units based on tetrafluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether and hydroxybutyl vinyl ether, respectively
Contains in mol%, [η] is 0.23dl/g, Tg
Formulation 5 using a fluorine-containing quaternary copolymer whose temperature is 27℃
It was made into a paint using the same recipe as above to obtain a top coat [Formulation 6]. [Formulation 7] Acrylic resin [Dainippon Ink and Chemicals Co., Ltd.]
Manufactured by Akridik A-169, non-volatile content
50%] 40 parts Titanium oxide 20 Anti-settling agent 1 Xylol 39 A paint of formulation 7 was prepared by roller kneading. [Formulation 8] (Main ingredient) Polyester resin (trade name: Desmofene 1100 manufactured by Bayer) 14.1 parts Polyester resin (trade name: Desmofene 800 manufactured by Bayer) 14.1 Titanium oxide 10 Xylol 6 Ethyl acetate 6 Butyl acetate 6 Cellosolve acetate 4.8 (Curing) agent) Polyisocyanate [Product name Mitek GP101A manufactured by Mitsubishi Chemical Industries, Ltd.: Non-volatile content 75%]
Part 39 The main agent and curing agent are mixed at the time of painting. Preparation of zinc-rich paint [Formulation 9] (Main ingredient) Epoxy resin 6 parts Xylol 10 Methyl isobutyl ketone 9 Zinc dust 65 (Curing agent) Polyamide resin 4 parts Xylol 4 Isobutanol 2 The above epoxy resin is a product name manufactured by Ciel Chemical Co., Ltd. Epicote #1001 [epoxy equivalent 450-520],
As the polyamide resin, Tomide #210 (amine value: 95±5) manufactured by Fuji Kasei Co., Ltd. was used. Mix the base agent and curing agent before use. Creating a binder coat [Formulation 10] (Main ingredient) Allyl ether resin 70 parts Styrene 19 Cobalt naphthenate (contains 6% metallic cobalt)
1 Titanium oxide 10 (hardening agent) Methyl ethyl ketone peroxide 1 part Mix the main agent and hardening agent before use. Examples 1 to 6 Mild steel plate of 150 x 50 x 1.6 mm [JIS G
3141) Apply anti-corrosive lining material using a roller according to the coating system in Table 1 to a dry film thickness of 500±50 microns, and after drying at room temperature for 7 days,
Dry film thickness of top coat is 100± by air spraying.
It was coated to a thickness of 10 microns, dried at room temperature for 7 days, and then subjected to a comparative test. However, in Example 5, a coated object was used, in which a mild steel plate was spray-painted with the Ginrich paint of the above formulation 9 to a thickness of 30 microns, and dried at 20°C and 75% RH for 3 days. In No. 6, an anticorrosive lining material was applied, and after drying, a binder coat of formulation 10 was applied to a thickness of 50 microns, and after drying, a top coat was applied.

[Table] Comparative Examples 1 to 6 Test pieces were prepared according to the coating system in Table 2 in the same manner as in Example 1, and subjected to comparative tests.

[Table] The test pieces obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were subjected to a weather-o-meter test, a lining test, and an interlayer adhesion test after the lining test. The results are shown in Table 3. In addition, the oxygen permeability of each isolated top coat was measured, and the results are shown in Table 4.

【table】

[Table] [Oxygen permeability was measured using a product science research institute type gas permeation measuring device (manufactured by Rika Seiki). 〓
It is clear from the comparison test results table in Table 3 above that the coating layer obtained by the coating method of the present invention has a gloss retention rate in the weatherometer test (5000 hours) that is different from that of the comparative example (1000 hours). The results were incomparably superior, and the lining test results were also very good, and the interlayer adhesion of the coating films was significantly different. The reason why the present invention provides a coating film with excellent corrosion resistance is not necessarily clear, but in the comparison of oxygen permeability (Table 4), which is a corrosion factor, it was found that the oxygen permeability of the top coat film produced by the method of the present invention was higher than that of the conventional one. compared to the coating film of
The extremely small size of 1/3 to 1/6 is thought to be one of the reasons for this.

Claims (1)

[Scope of Claims] 1 (a) A step of applying an anticorrosion lining material on the object to be coated and drying it at room temperature, (b) (a) 40 to 60 mol% of fluoroolefin, 5 to 45 mol% of cyclohexyl vinyl ether, An overcoat containing a fluorine-containing copolymer consisting of 5 to 45 mol% of alkyl vinyl ether, 3 to 15 mol% of hydroxyalkyl vinyl ether, and 0 to 30 mol% of other comonomers, and (b) a polyvalent isocyanate. An anticorrosive coating method consisting of the steps of applying paint and drying it at room temperature to form a top coat. 2 The anticorrosive lining material contains 100 parts by weight of unsaturated polyester resin or epoxy resin, and 10 to 10 parts by weight of flat pigment.
The anticorrosive coating method according to claim 1, which is a composition comprising 150 parts by weight and the required amount of a hardening agent. 3. The anticorrosive coating method according to claim 1, wherein the fluoroolefin is chlorotrifluoroethylene and/or tetrafluoroethylene. 4. The anticorrosive coating method according to claim 1, wherein the alkyl vinyl ether contains a linear or branched alkyl group having 2 to 8 carbon atoms. 5. The anticorrosive coating method according to claim 1, wherein the hydroxyalkyl vinyl ether is hydroxybutyl vinyl ether. 6. The anticorrosive coating method according to claim 2, wherein the flat pigment is glass flakes and/or mica.