JPS58133870A - Corrosion preventive coating method - Google Patents

Abstract

PURPOSE:To form corrosion preventive coating having excellent corrosion resistance and weather resistance by forming a a binder coat layer and a sealer coat layer on an undercoating paint film and applying paint contg. a fluorocopolymer and polyvalent isocyanate thereon. CONSTITUTION:Rust preventive paint of oil or alkyd resins is coated as undercoating paint on a substrate and is dried at ordinary temp., whereby an undercoating paint film is formed. After a binder coat layer by phenol alkyd resin paint contg. flat pigments and a sealer coat layer by epoxy resin paint are formed thereon, the top coating paint contg. a fluorocopolymer consisting of 40-60mol% fluoroolefin, 5-f45% cyclohexyl vinyl ether, 5-45% alkyl vinyl ether, 3-15% hydroxy alkyl vinyl ether and 0-30% other comonomers and polyvalent isocyanate is coated thereon and is dried at ordinary temp., whereby a top coating paint film is formed and the corrosion preventive coating is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an anti-corrosion coating method capable of forming a tough coating film with extremely excellent anti-corrosion properties and weather resistance. Conventionally, nine undercoats have been applied to steel, cabinet structures, etc. that are installed outdoors, taking into account the ability to block moisture and corrosion-promoting substances, adhesion to metal surfaces, and corrosion inhibition with rust preventive additives. On top of that, an intermediate coat is applied as necessary for the purpose of improving adhesion between the undercoat and topcoat, mitigating the effects of differences in physical properties between the undercoat and topcoat, and adding film thickness. ,
It is common to apply a top coat that has weather resistance, mechanical strength, etc. However, as the undercoat paint, alkyd resin rust preventive paint is widely used instead of oil-based rust preventive paint because it has the advantage that it can be coated even if the surface of the object to be coated is relatively poorly conditioned, such as 21'I scuffing. ing. .

As for the above-mentioned topcoat paints, alkyd resin paints, chlorinated rubber paints, etc. are widely used. Depending on the type of stone, it had to be repainted every 5 to 6 years, or as early as 2 to 6 years.

On the other hand, as steel structures such as bridges and tanks become larger, the cost and man-hours required to replace the sheath 9 tend to increase. There has been a strong demand for paints for a long time.

In general, in the corrosion reaction of painted steel structures in a neutral environment F such as the atmosphere, the oxygen reduction reaction dominates the canonical reaction in corrosion, so the oxygen permeable paper in the coating film is It is considered to be.

Taking into account the dominance of the cathode reaction in corrosion due to the oxygen reduction reaction, the critical current density (Imax) corresponding to the one-bow corrosion rate of the steel under the coating film is expressed by the following equation.

Imax = Mmax * na F2KIICol
InF/d [Mmax: Diffusion dissolved oxygen.

In: oxygen diffusion coefficient.

d: Thickness of ameliorating layer and coating film thickness).

n: Number of reaction electrons.

F: Faraday constant number.

CO: Oxygen concentration, ] In order to reduce the corrosion rate of steel under the coating, the coating must be very thick, or if the coating thickness is 1' V! - It is necessary to reduce the diffusion of dissolved oxygen or the oxygen diffusion coefficient, ie, the oxygen permeability. It is also necessary to suppress the reduction in film thickness due to chalking or the like for a long period of time. If the oxygen permeability of 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 will be reduced by half.
This is a very important factor in the long-term corrosion resistance of fine materials.

However, the alkyd resins and chlorinated rubbers used as color vehicles in the above-mentioned topcoat paints have relatively high oxygen permeability, which promotes υ'-6 eclipse under the paint film, causing the coating to deteriorate. In addition to being prone to film defects, the resin and pigment of the top coating paint are likely to deteriorate due to ultraviolet rays, etc., resulting in loss of gloss and discoloration due to discoloration, chalking, cracking, etc. Therefore, long-term corrosion resistance and weather resistance could not be expected at all.

However, silicone resin has recently been developed as a resin with good weather resistance, and attempts are being made to apply it to top coats.

However, 7 Recon alkyd resin and silicone acrylic resin, which dry at room temperature, have relatively high oxygen permeability, so they must be overcoated! Even if the weather resistance of the coating film improves to some extent, the corrosion inhibition effect under the coating film cannot be improved, and the top coating film is soft.
It has the drawback of being easily stained and scratched, and at the same time becoming resin/whitening. However, even if the above-mentioned resin does not deteriorate over a long period of time and has luster, the pigment on the surface layer of the paint film fades and the color changes greatly from the initial color, so it cannot withstand use for the same amount. . The purpose of the present invention is to overcome all the drawbacks of the prior art as described above, and to provide a corrosion protection coating method using a coating system that has long-term corrosion resistance and 1lir1 resistance.
This is what we are trying to provide.

1 (1) The present invention is based on (1) (b) +1A coating of an oil-based anti-corrosion paint or an alkyd resin anti-corrosion paint as an undercoat paint, and drying at room temperature. (b) A step of applying a phenol alkyd resin paint containing a flat pigment onto the cooled film and drying it at room temperature to form a binder coat layer, (c) A step of forming a binder coat layer on the binder coat layer. , a step of applying an epoxy resin paint and drying it to form a sealer coat 1@; incidentally) (a) 40 to 60 mol% of fluoroolefin;
/ 5 to 45 mol% of chlorhexyl vinyl ether, 5 to 45 mol% of alkyl vinyl ether, 6 to 15 mol% of hydroxyalkyl vinyl ether, and other co'l
(b) A process of applying a top coat of isocyanate and drying at room temperature to form a top coat film. 12) (a) Applying an oil-based anti-rust paint or an alkyd resin anti-rust paint as an undercoat onto the object to be coated,
(b) A step of applying a phenol alkyd resin paint containing a flat pigment on the undercoat pattern and drying it at room temperature to form a binder coat layer; (c) A step of applying an epoxy resin paint containing a flat pigment on the binder coat layer and drying it at room temperature to form a sealer coat layer, and (a) fluoroolefin 40 to 60 mol%,
A fluorine-containing copolymer consisting of 5 to 45 mol% of cyclohexyl vinyl ether, 5 to 45 mol% of alkyl vinyl ether, 6 to 15 mol% of hydroxyalkyl vinyl ethyl, and 0 to 60 mol% of other co-central; b) Applying a top coat containing a polyvalent incyanate and drying at room temperature to form a top coat.

The oil-based anticorrosive paint as the undercoat 9 paint used in the anticorrosive coating method of the present invention is, for example, drying or semi-drying oil such as linseed oil, shakubu oil, tung oil, safflower oil, or boiled oil of these oils. as a color vehicle, red lead, lead zinc oxide, basic chromium-blown lead, lead, zinc powder, zinc chromate,
It is a paint that uses lead zinc chromate, calcium lead oxide, etc. as an anti-corrosion NI agent, and the alkyd tree used in the method of the present invention; By condensing polybasic acids such as acids, polyhydric alcohols such as pentaerythritol, sorbitol, trimethylolpropane, glycerin, and ethylene glycol, and oils or fatty acids such as linseed oil, soybean oil, tung oil, and safflower oil, [ Using alkyd resin as a color vehicle, red lead, lead oxide, basic lead chromate,
This is a paint that uses anti-corrosion pigments such as lead cyanamide, zinc powder, zinc chromate, and red lead zinc chromate. These oil-based anti-rust paints or alkyd resin anti-rust paints are specifically compliant with, for example, JIS K 5621. JIS K
5622. JISK 5625. JIS K56
24. JIS K 5625. JIS K562
6゜JIS K 5627. JIS K 5628
It is described in etc.

The above-mentioned oil-based rust-preventing paint or alkyd resin rust-preventing paint has the advantage that it can be coated even if the surface of the object to be coated has a relatively poor substrate condition, such as type 2 staining.

In addition, the binder coated phenol alkyd resin paint used in the method of the present invention and polybasic acids such as phthalic anhydride, isophthalic acid, terephthalic acid, and maleic anhydride, pentaerythritol, sorbitol, and trimethylolpropane , polyhydric alcohols such as glycerin and ethylene glycol, oils or fatty acids such as linseed oil, soybean oil, tung oil, and safflower oil, and phenol formaldehyde.The main color vehicle is a resin obtained by co-condensing, for example, scales. This is a paint whose main pigment is a flat pigment such as oxide powder, glass flakes, or aluminum powder.

The preferable solids weight ratio of the phenol alkyd resin vehicle and the flat material is 100 weight parts for the former and 40 weight parts for the latter.
The ratio is about 150 to 150 leaflets.

The phenol alkyd resin paint includes base coat 9 paint and 7-
It is between the sealer coat and the sealer coat and can improve the adhesion of both coats and prevent the lifting of the undercoat film caused by the solvent imprinted in the sealer coat. In addition, (with the binder coat of l + J, chalking and paint film deterioration occur early, so a sealer coat must be applied at the latest within 1 to 2 months after the formation of the binder coat, but according to this 11th edition) Since the binder coat used in the J method does not have the above-mentioned drawbacks, the sealer coat application interval is greatly improved to 12 months or more.

The epoxy resin paint as a sealer coat used in the method of the present invention is an epoxy resin coloring agent having two or more 7 epoxy groups in the molecule, and coloring pigments and wood pigments commonly used therein. It is a paint consisting of a main ingredient made by kneading an anti-settling agent, a dispersant, and a diluent, and an amine-based curing agent.

Examples of the epoxy resin include, for example, bisphenol type epoxy resins such as Epicoat 828, 864, 836, manufactured by Shell Chemical Co., Ltd., which are generally commercially available.
1001, 1004, DX-255: Ciba Geigy (manufactured by 4e! Color product name: Araldite GY-260: Dow Chemical (product name: DER330, 331, 337 manufactured by Nippon Ink and Chemicals, 1) Product name: Epicron 8o os: DEN 431, DEN 438 manufactured by Dow Chemical Co., Ltd., which is generally commercially available as a phenol novolac type epoxy resin; Product name Araldye L-CT-508 = Dow Chemical, Tori product name DER-752, 736; As an ester-type epoxy resin, for example, Dai 11 Ink Chemical Industry Co., Ltd. (medium product name Ebicuron 200, same 4oo; s-shaped) 11
i-aliphatic epoxy tree 1111, for example, Japan backshore, →
Epoxidized polybutadiene, such as BF-1000 manufactured by Co., Ltd., can be used.

Furthermore, Evokin thread compounds, which can be easily inferred from these resins, and the conductors of the above-mentioned epoxy resins can also be used, and are included within the technical scope of the present invention.

For example, polyol type epoxy resin, alicyclic 1r xyta
41i? , halogen-containing epoxy resin, etc. are heated to 1'°C.

Further, as the curing agent for the epoxy resin, those commonly used for paints, such as Fmin adduct and polyamide resin, can be used.

Examples of the curing agent used in this explanation are Fuji Kasei Kogyo, which is generally commercially available as a polyamide resin → Development product name Tomide Y-25, Tomide 245, Tomide 2400, Tomide 25
00,: Condolences - General Rumored Item Name: Zenamide 2000,
Persamide 115, Persamide 125: Sanwa Chemical (1) Product name: Sanwa Chemical 320, Persamide 330, Persamide
; As amine adduct resin, Fuji Kasei Kogyo 4, product name Tomide 238, Fuji Cure-202 = Asahi Denka 4 product name, Adeka Hardener EH-531; As aliphatic polyamine, Sansho Kagaku +4, N 1i', 6 product name Sanmide T
-1t]0, D-100, P-100; Epomate B-002 manufactured by Ajinomoto 4 as a heterocyclic diamine derivative;
Examples include C-002 and S-005.

Addition of the curing agent to epoxy resin 1111 resistance 1-! :
07 to 1 for before and after use, that is, for 1 day use of epoxy resin
．． It is in the range of about 6 clear days.

Furthermore, polyinocyanate can also be used as the hardening material 011 for the front 6 piepoxy resin. 1 The polyisocyanate is a polyisocyanate having two L-) and L incyanate groups in one molecule, such as ethylene diisocyanate, propylene diino-7anate,
Tetramethylene diino-7anate, hexamethylene diisonanate, decamethylene diinocyanate, l11
-phenylene diisocyanate, p-phenylene diisocyanate, 2.4-) rylene diisocyanate, 2
．． 6-) lylene diisocyanate), 1.5-naphthylene diisocyanate, 4.4', 71#-) liphenylmethane triinocyanate 1. ! ,,! l'-diphenylmethane diisocyanate, 3,5'-dimethyl-4,4'-diphenylene diisocyanate, m-
Polyisocyanates such as xylylene diisocyanate, p-xylylene diisocyanate, inophorone diisocyanate, lysine isocyanate, and an excess of the above-mentioned in7anate compounds, such as ethylene glycol,
Propylene glycol, 1,3-phthylene glycol,
Neopentyl glycol, 2゜2, A-t+))fl1
, 3-bentanediol, hexamethylene glycol,
Cyclohexane dimetatool, trimethylolpropane, hexanetriol, glycerin, pentaerythritol)
Examples include polyisocyanates having two or more functionalities obtained by addition reaction with low-molecular polyols such as polyol, polyisocyanates having a biuret structure, polyisocyanates having allophanate bonds, and the like. The mixing ratio of the epoxy resin and polyisocyanate is (hydroxyl group in epoxy resin)/(isocyanate group in polyisocyanate): 1/1.3 to 170.5 (equivalent ratio)
A range of is preferred.

One embodiment of the present invention includes a composition in which a flat pigment is added to the epoxy resin paint. As the flat pigment, the same type as used in the binder coat layer can be used without any problem. The flat pigment has a pigment ratio of 40 to 15 [J rl
j b: Ratio of about 1 part.

The present inventors have separately filed an application for a method of providing a phenol alkyd resin binder coat layer on an oil-based or alkyd resin rust-preparing paint film, and then applying an overcoat and coating. Therefore, the interval required to apply the top coat to the phenol alkyd resin binder coat layer l- (maximum coating interval) is 3 days or more because the binder coat is an oxidative polymerization type, and the top coat is A problem arose in that the undercoat was likely to dry incompletely (due to the strong solvent causing sluggishness).

The present invention uses epoxy 7i, l i on the binder coat layer.
By providing a sealer coat with J・C paint,
This shortens the shortest interval between painting stations 111 until the top coat is applied.

In addition, by providing a sealer coat containing a flat additive to the epoxy resin paint, the adhesion of the coating can be further improved, and the weather resistance of the lar coat can also be improved. It is also possible to lengthen the maximum interval between coats until the top coat is used.

Therefore, in the present invention, by using a sealer coat, it is possible to shorten the minimum painting interval until the top coat is applied, and conversely, if necessary, the maximum painting interval can be lengthened even if the sealer coat is left as it is after being applied. For,
This made it possible to greatly expand the range of painting operations.

The fluorine-containing copolymer used as the topcoat material used in the coating method of the present invention contains fluoroolefin, cyclohexyl vinyl ether, alkyl vinyl ether, and hydroxyalkyl vinyl ether as essential constituents of 40 to 60 mol % and 5 to 45 mol %, respectively. mol%, proportions of 5-45 mol% and 5-15 mol%, respectively 4
5-55 mol%, 10-30 mol%.

It is recommended that the content be 10 to 35 mol% and 5 to 16 mol%.3, fluoroolefin content with a high content is unfavorable from the viewpoint of weather resistance/it is often used before manufacturing. This causes inconvenience. Also, there are 4 it of products with too high fluoroolefin-containing IIj before production. On the other hand, those with a low content of 7 chlorohexyl vinyl ether are not preferred because the hardness when formed into a coating film are undesirable, and those with too low alkyl vinyl ether content are undesirable because the flexibility is decreased.

If the fluorine-containing copolymer used in the coating method of the present invention contains hydroxyalkyl vinyl ether in the proportion within the above range, it may impair various useful properties as a paint paste and may not cure at all. This is particularly important from the perspective of improving sexual performance. In other words, if the hydroxyalkyl vinyl ether content is too high, the copolymer's solubility 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. In addition, it reduces the flexibility of the cured coating film, reduces the gelation time (pot life) in the presence of curing and τ1, and does not significantly improve the workability of the coating. So I don't like it. In addition, if the sulfur content is too low, the effect of improving curability is lost, resulting in an increase in curing time, a decrease in solvent resistance, stain resistance, etc. of the cured coating film, and furthermore, it may cause poor adhesion with Sealer Coat IQ. This is not preferable because it causes disadvantages such as loss of quality.

In the above-mentioned fluorine-containing copolymer, fluoroolefins and barhaloolefins, particularly chlorotrifluoroethylene or tetrafluoroethylene, are preferably employed1, and as the alkyl vinyl ethers,
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. Incidentally, the fluoroolefins and alkyl vinyl ethers are not limited to being used alone, but may also be used in the form of a mixture of 24'riμ.

The fluorine-containing copolymer may contain units based on co-educational 1-isomers other than the above-mentioned four essential components within a range not exceeding 30 mol %.

Examples of such conjugate bodies include olefins such as ethylene, propylene, and isobutylene, haloolefins such as pinyl chloride and vinylidene chloride, unsaturated carboxylic acid esters such as methyl methacrylate, vinyl acetate, vinyl n-butyrate, etc. Examples include vinyl carboxylates.

The fluorine-containing copolymer has an intrinsic viscosity of 0.05 measured at 30°C in tetrahydrofuran in an uncured state.
~2.0 dl/f especially 0.07~08II],
/ f can be advantageously adopted.

If the viscosity is too low, the mechanical strength will decrease, and if the blade is too high, when applied as a solution-type paint, the solution concentration will have to be lowered from the viewpoint of viscosity, resulting in poor workability. Both are undesirable because they cause damage.

The fluorine-containing copolymer as described above has a predetermined ratio of 11.
! A copolymerization reaction is carried out by applying a polymerization initiator such as a water-soluble initiator or an oil-soluble initiator or a polymerization initiation source such as ionizing radiation to the monomer mixture in the presence or absence of a copolymerizing medium. It can be manufactured by tightening.

When using the thus obtained fluorine-containing copolymer as a top coating, various solvents can be used.
In addition to aromatic hydrocarbons such as xylene and toluene, alcohols such as n-butanol, esters such as butyl acetate, ketones such as methyl isobutyl ketone, and glycol ethers such as ethyl cellosolve, various commercially available thinners are also used. It is possible.

The copolymer and the solvent are mixed using a ball mill, an intoshiker, a sand mill, a jet mill, a three-roll mill, a kneader, etc., by adding a coating agent, a leveling agent, an anti-gelling agent, an ultraviolet absorber, etc. You can also do that.

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 inocyanate groups in one molecule, such as ethylene diisocyanate, propylene diisocyanate, tetramethylene diisonoanate, hexamethylene diiso/anate, and decamethylene. Diinocyanate, l11-phenylene diiso7anate, p-phenylene diiso7anate, 2.1-) rylene-cyinoa'r
2.6-) rylene diisocyanate, 1,5
-Naphthylene-diisocyanate, 4.4', /l#
-triphenylmethanetriisocyanate-1.,4.4'
-diphenylmethane-diisocyanate, wax 3'-dimethyl-4,4'-diphenylene-diisocyanate,
m-xylylene di-inocyanate, p-xylylene-
Polyvalent isocyanate such as diisocyanate, inophorone diisocyanate, lysine isocyanate 7 and an excess of the isocyanate compound, such as ethylene glycol, propylene glycol, 1,5-phthylene gelicol, neopentyl glycol, 2°7.1-11J+
Bifunctional or higher polyvalent isocyanate obtained by addition reaction with low-molecular polyols such as 1,3-bentanediol, hexamethylene glycol, cyclohexane dimetatool, trimethylolpropane, hexanetriol, glycerin, pentaerythritol, etc. Examples include polyvalent isocyanate having a rett structure, polyvalent incyanate having an allophanate bond, and the like.

Among the polyvalent incyanates, non-yellowing diisocyanates such as hexamethylene diisocyanate and inphorone diisocyanate and adducts thereof are particularly useful.

The mixing ratio of the fluorine-containing copolymer and the polyvalent isocyanate is (hydroxyl group in the fluorine-containing copolymer)/(isocyanate group in the polyvalent isocyanate) -1/13 to 1/n,
A range of s (total ratio) is preferred.

However, 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.

The anti-corrosion coating method of this invention 1
Apply the oil-based anti-rust paint or the alkyd resin anti-corrosive paint onto the workpiece whose A Mb has been adjusted to +1H or more at a rate of 1.1:l1 so that the dry and broken film is approximately 50 to 100μ.
Apply one or more coats with a hair, spray paint machine, roller, etc. and dry at room temperature. General: :'+, 1 The undercoat film is formed by drying at room temperature to the same level as the shrine.

Next, the phenol alkyd resin paint is applied onto the undercoat film so that the dry film thickness is about 60 to 80 p.
Apply one or more coats with a brush, sprayer, roller, etc., and allow to dry at room temperature. A K-rebinder coat layer is usually formed after drying at room temperature for 6 to 7 days.

Then, on the binder coat layer, apply the epoxy/resin as a color vehicle/-Larcoat to a dry lq thickness of about 10 to 5.
Apply once or every time using a brush, spray coater, roller, etc. to a coating thickness of about 0μ, and dry at room temperature. A sealer coat layer is usually formed by drying at room temperature for 4 hours to 51 hours.

Finally, apply a top coat obtained by mixing the above fluorine-containing copolymer and polyvalent isocyanate on the sealer coat layer just before use, using a brush or spray paint to give a dry film thickness of about 15 to 70 μm. Apply one or more coats with a roller or the like and dry at room temperature. The top coat film is usually formed by drying at room temperature for 2 to 4 days.

The objects to be coated to which the method of the present invention is applied include iron, metallicon (#I4 plate with zinc or zinc, and thus the coating layer 1・τL1° obtained by the method of the present invention is one of the corrosion factors. Because the permeability of certain RW and base materials is extremely low, it maintains long-term corrosion resistance and prevents corrosion of the coated material, and also has excellent weatherability, making it difficult to use with conventional coating systems. The interval between repainting is unimaginably long, and therefore the cost and man-hours required for repainting can be significantly reduced.
1 roll has excellent recoatability, so 1 roll with repaint specifications
・(; [1 is also very advantageous. The details of the present invention will be explained below with reference to 10 and 1.

``Part'' or ``%'' means ``ton coagulation part'' or ``weight %.'' r indicates 1゜ noni ml + jl + (1) Creation of F cooling paint Linseed oil Boiled oil 10 parts large (), oil modified medium oil Type alkyd resin (solid content) 10 calcium carbonate 50 red iron
5 metal dryer 2
Anti-skinning agent 1 Anti-settling agent
1 mineral spirits
20 This mixture was kneaded in a bot mill for 24 hours to obtain a coating material.

(11) Preparation of binder coat Linseed oil Boil oil 5 parts Phenol alkyd resin (solid content) 15 Synthetic salmon flakes Iron oxide
40 Calcium carbonate 1
0 Metal dryer 1 Anti-skinning agent 1 Anti-settling agent
1 mineral spirits
20 This mixture was kneaded in a pot mill for 24 hours to obtain a binder coat (g).

(Main ingredient) Titanium oxide 20 talc
15 Precipitated barium sulfate
15 Anti-settling agent (organic bentonite) 2 Methyl isobutyl ketone 15 Kizilol
10 The above composition was kneaded with a roller to obtain a main ingredient.

(Curing agent) Inobutanol 40 Stir the above 14 components with a disper to obtain a hardened liquid. Immediately before use, a curing agent was mixed in a ratio of 20 parts to 80 parts of the base resin to obtain a sealer coat (T).

(+v)-Preparation of paint by coating Lorotrifluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether, and hydroxy-7-thyl vinyl ether at 51.2% each.
Mol%, 17.1 mol%.

Contains at a ratio of 225 mol% and 9.1 mol% j+'
+l Viscous 1! ″((50℃ in tetrahydrofuran)(
[η]) is 0.21 dl/f, glass transition temperature (DS
C10℃/m rise! i! F) ('rf) is 45°C.
The mixture was dissolved in a mixed solvent of 0 parts of methyl inopdyl ketone and 120 parts of methyl inopdil ketone, and then 42 parts of bleached titanium was added thereto and kneaded in a pot mill for 2 hours to obtain a main ingredient for a top coat.

Immediately before use, a curing agent consisting of 8 parts of hexamethylene diisocyanate and 15 x 10" parts of dibutyltin dilaurate was mixed with the base material to obtain a top coat.

() Preparation of test piece Sand-plast treated steel plate (JIS G 3111:
70x150x1.61+111), the undercoat paint was first applied with air paint twice at intervals of one day, and then allowed to dry for one week to obtain an undercoat film with a film thickness of 80μ.

Next, the binder coat (G) was air sprayed and dried at room temperature for 3 days to obtain a binder coat layer with a film thickness of 50μ, and then the sealer coat (G) was air sprayed and dried at room temperature for 24 hours. A sealer coat layer having a thickness of 20 μm was obtained.

Finally, the above-mentioned top coat V paint (G) was air-sprayed onto the sealer coat layer and dried at room temperature for 2 days to obtain a top coat film with a thickness of 30 μm.

The obtained test piece was subjected to a comparative test described later.Example 2 Linseed oil 17 parts Lead Red 76 Metal dryer 2 Anti-settling agent
2 Anti-skinning agent
2 Mineral spirits 2゜This mixture was kneaded in a pot mill for 24 hours to obtain a paint (g).

Soybean oil modified medium oil type alkyd resin (solid content) 15 parts Synthesis - Flaky iron oxide 4° Calcium carbonate 5 Metal dryer
5 Anti-skinning agent
1 Anti-settling agent 1 Mineral spirit 60 This mixture was kneaded in a pot mill for 24 hours to obtain a binder coat (B).

(iii) Preparation of sealer coat Using the sealer coat (4) of Example 1, 50.8 mol% of each of the degrees based on 9-tetrafluoroethylene, cyclohexyl vinyl ether, ethyl vinyl ether, ethyl vinyl ether, and ethyl vinyl ether were added.16.
9 mol%, 22.8 mol% and 9.5 mol%, [η] is 0.23 dl/V, Tf is 2
The fluorine-containing quaternary copolymer at 7° C. was made into a paint using the same formulation as in Example 1 to obtain a top coat (9).

(V) Preparation of test piece A test piece was prepared by the same method as in (V) of Example 1, and then subjected to a comparative test.

Example 3 (1) Preparation of undercoating paint Soybean oil modified medium oil type alkyd resin (solid content) 25 parts Red iron 45 Metal dryer 3 Anti-settling agent
2 mineral spirits 10
Lead zinc oxide 20 This mixture was kneaded in a pot mill for 24 hours to obtain an undercoat paint (C).

The binder coat (g) of Example 1 was used.

The sealer coat (g) of Example 1 was used (+v
)-L-, Preparation of Coating Paint The top coating paint (B) of Example 2 was used.

() Preparation of test piece A test piece was prepared by the same method as in (V) of Example 1, and then subjected to a comparative test.

Example 4 (1) Preparation of undercoat 9 paint Soybean oil modified medium oil type alkyd resin (solid content) 30 parts red iron, 0 thick chromate 30 gold 10,000 parts dryer
6 Anti-settling agent
2 Mineral spirits 20 This mixture was kneaded in a pot mill for 24 hours to obtain an undercoat.

(1j) Preparation of binder coat The binder coat of Example 2) (B) t (used).

Using the sealer coat (g) of Example 1,
) Preparation of top coat paint 1, (V) using the top coat paint (G) of Example 1 above
Preparation of Test Piece A test piece was prepared in the same manner as in (V) of Example 1, and then subjected to a comparative test.

Example 5 (1) Preparation of undercoat paint The undercoat paint from Example 1 was used.

(11) Creation of binder coat The binder coat (G) of Example 1 was used for coating.

(iii) Creation of sealer coat (main r1li) Scaly iron oxide 65 talc
15 Sedimentation ■ Inhibitor (organic bentonite) 2 Methyl isobutyl ketone 16 Xylol
10 The above fourth product was kneaded with a roller to obtain a main ingredient.

(Curing agent) Inbutanol 40 The above formulation was stirred with a disper to prepare a curing agent. Immediately before use, add 20 parts of curing agent to 80 parts of the main agent. (Mixed to obtain sealer coat (B).

(1) Preparation of top coat paint) The top coat paint (B) of Example 2, F411f, was used.

A test piece was prepared by the same method as in Example 1 (V) and then subjected to a comparative test.

Examples 6 to 8 Using the coating system shown in Table 1, test pieces were prepared using scissors in the same manner as M in Example 111 and were subjected to comparative tests.

Table 1 Coating system of examples Comparative example 1 (1) Preparation of undercoat paint The undercoat paint (g) of Example 1 was used.

The binder coat (4) of Example 1 above was used.

(-) Preparation of top coat paint Soybean oil modified medium oil type alkyd resin (solid content) 25 parts Titanium oxide 25 Calcium carbonate 10 Metal dryer 5 Anti-settling agent 1 Anti-skinning agent 1 Mineral spirit 15 Knead the above mixture in a pot mill for 24 hours and topcoat paint (C
) obtained in 1.

(IV) Preparation of test piece A test piece was prepared by the same method as in (V) of Example 1 above, and then subjected to a comparative test.Comparative Example 2 (1) Preparation of undercoat paint Example 1 above. The undercoat paint body) was used.

(1) Creation of binder coat The binder coat (g) of Example 1 was used.

(Mountain) Preparation of top coat paint Chlorinated rubber 25 parts Chlorinated paraffin 40% 10 Titanium oxide
, 5 anti-settling agent
1 Kijiroru 64 The above mixture was kneaded in a dead mill for 24 hours to obtain a top coating.

(1) Preparation of test piece A test piece was prepared in the same manner as in (V) of Example 1, and then subjected to a comparative test.

Comparative Examples 5 to 5 Test pieces were prepared using the coating system shown in Table 2 in the same manner as M in Example 1, and then subjected to a comparative test. However, for coating systems that do not use binder coat,
A top coat was applied directly onto the base coat.

Table 2 Comparative example coating system (Note 1) Nlicon alkyd resin solution [Toshiba Silicon ■
Product name YR5116: Non-volatile content 48.3%] 40 parts,
The mixture was kneaded for 24 hours in a titanium oxide mill and used as a top coat (g).

The test pieces obtained in Examples 1 to 8 and Comparative Examples 1 to 5 were subjected to a grain adhesion test, an impact resistance test, a salt spray resistance test, a salt water immersion test, and a sunshine weather test. All oxygen permeability measurements were carried out on isolated coatings of paint. The results are shown in Tables 5 and 4.

Table 4 Comparison of Oxygen Permeability of Top Coat Films Oxygen permeability was measured using a gas permeability measuring device (manufactured by Rikagaku Seiki Co., Ltd.) at Product Science Institute.

From the comparative test results table (Table 3), it is clear that the corrosion resistance (salt spray resistance test, salt water immersion test) of the test piece obtained by the coating method of the present invention is better than that of the test piece of the comparative example. It was extremely immersive.

Furthermore, it is clear from Table 3 that the coating layer obtained by the method of the present invention has good weather resistance (Sunshine Weather-Ometer).
It was extremely superior to conventional coatings.

The reason why the present invention provides a coating film with excellent corrosion resistance is not necessarily clear, but in the comparison of permeability to oxygen, which is a corrosion factor (Table 4), It is thought that this is due to the fact that the surface area is extremely small, about 115 to 1/1 of that of conventional coatings.

Claims (1)

[Scope of Claims] (1) (a) A step of applying an oil-based anti-rust paint or an alkyd resin anti-corrosive paint as an undercoat onto the object to be coated, and drying at room temperature to form a multi-coat undercoat film; (b) Applying a phenol alkyd resin paint containing flat pigments on the undercoat film and drying at room temperature to form a binder coat layer; (c) Applying an epoxy resin paint on the binder coat layer. and drying at room temperature to form a sealer coat layer; incidentally) (a) 40 to 60 mol% of fluoroolefin;
A fluorine-containing copolymer consisting of 5 to 45 mol% of cyclohexyl vinyl ether, 5 to 45 mol% of alkyl vinyl ether, 3 to 15 mol% of hydroxyalkyl vinyl needle, and 0 to 30 mol% of other comonosomes; b) An anticorrosive coating method comprising the steps of applying a top coat containing a polyvalent isocyanate and drying at room temperature to form a top coat. (2) Claim No. 1, wherein the flat pigment used in the binder coat layer is one or a mixture of two or more of scaly iron oxide, glass flakes, and aluminum powder.
Anticorrosion coating method described in section. f31 The anticorrosive coating method according to claim (1), wherein the fluoroolefin is chlorotrifluoroniylene 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) Claim No. 1 in which the hydroxyalkyl vinyl ether is hydroxybutyl vinyl ether
) The anticorrosion coating method described in section 2. (6) (a) Apply an oil-based anti-rust paint or an alkyd resin anti-rust paint to the coated object as an undercoat,
A step of drying at room temperature to form an undercoat film; (b) A step of applying a phenol alkyd resin paint containing a flat pigment under the coating film and drying at room temperature to form a binder coat layer. A step of applying an epoxy resin paint containing a flat pigment on the binder coat layer and drying it at room temperature to form a sealer coat layer, then G→(a) fluoroolefin 40 to 60 mol%,
/ A fluorine-containing copolymer consisting of 5 to 45 mol% of chlorhexyl vinyl ether, 5 to 45 mol% of alkyl vinyl ether, 3 to 15 mol% of hydroxyalkyl vinyl ether, and 0 to 30 mol% of the co-educational group; b) An anti-corrosion coating method comprising the steps of applying a top coat containing polyisocyanate and drying at room temperature to form a top coat. (7) The monolithic pigment used in the binder coat layer and the sealer coat layer is one or a mixture of two or more of the following: 1, flaky iron oxide, glass flakes, and aluminum powder. ), the anticorrosive coating method described in IQ. (8) The anticorrosive coating method according to claim 16, wherein the fluoroolefin is chlorotrifluoroethylene and/or tetrafluoroethylene. (9) The anticorrosive coating method according to claim 16, wherein the alkyl vinyl ether contains a straight (spout or branched) alkyl group having 2 to 8 carbon atoms. (Claim No. 6 in which the 101 hydroxyalkyl vinyl ether is hydroxybutyl vinyl ether)
Corrosion protection covering method described in section.