JP2023046836A - Anticorrosive coating composition - Google Patents

Abstract

SOLUTION: An anticorrosive coating composition contains (A) epoxy resin, (B) amine curing agent, (C) reactive butadiene acrylonitrile and (D) magnesium oxide, the (D) magnesium oxide having a BET specific surface area of 3.0 m2/g or more, the solid content of the (D) magnesium oxide being 5-15 mass%.EFFECT: An anticorrosive coating composition can be directly applied to a rusted face and can form a coating layer having excellent anticorrosive and adhesive properties and also having excellent flexibility.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to an anticorrosion coating composition, and more particularly to an anticorrosion coating composition containing an epoxy resin and having excellent anticorrosion and adhesion properties.

Steel structures are used in various applications and environments. However, steel structures are corroded by various factors, and there is a risk of collapse due to a decrease in strength accompanied by rusting. Various methods such as painting, metal spraying, and lining are used as simple methods for suppressing these corrosions.

In anti-corrosion coating, it is possible to extend the service life of steel structures by repainting them periodically, and it is possible to maintain steel structures over the long term through regular maintenance. Become.

US Pat. No. 6,200,005 describes a coating containing MgO, amino acids, and a film-forming resin, which is said to be a corrosion resistant coating that does not contain toxic chromate pigments.

In Patent Document 2, a main agent component containing a liquid epoxy resin and a silane coupling agent and a curing agent component containing an amine-based curing agent are contained, and the main agent component and/or the curing agent component are liquid hydrocarbons. An epoxy resin composition containing a resin is described, and it is described that this epoxy resin composition is capable of forming a coating on the surface of a substrate having excellent adhesion to the substrate, water resistance, and anti-corrosion properties. .

Patent Document 3 discloses an epoxy resin composition containing a bifunctional or higher functional epoxy resin derived from a higher fatty acid or a derivative thereof, an epoxy resin other than the epoxy resin, a terminally reactive butadiene acrylonitrile copolymer, and polyamidoamine. It is described that this epoxy resin composition can follow cracks and can protect concrete structures on wet surfaces by simple methods such as roller coating and brush coating.

Patent Document 4 discloses an antirust coating composition containing a coating film-forming resin selected from epoxy resins and the like, a cross-linking agent, and magnesium oxide, wherein the magnesium oxide has a lattice constant of 0.4214 nm. and a BET specific surface area of 2.0 m ² /g or less. It is described that it can exhibit rust prevention properties and that it can form a coating film exhibiting excellent moisture resistance.

Japanese Patent Publication No. 2016-537481 JP-A-2005-15572 JP 2015-59195 A Japanese Patent No. 6690046

Usually, when rust and other abnormalities appear in steel structures due to various factors, it is necessary to completely remove the rust and the like by blasting, etc., but this work requires a great deal of time and labor. , there were some problems such as difficult processing due to the structure. Therefore, there has been a demand for a paint which can simplify the process of removing rust and which can exhibit good anti-corrosion properties and adhesion even when applied directly to rusted areas.

The compositions and the like described in Patent Literatures 1, 2 and 4 are not intended to be directly applied to rusted areas. In addition, although the composition described in Patent Document 3 describes adhesion to rusted surfaces, there has been a demand for even better adhesion to rusted surfaces.

An object of the present invention is to provide an anticorrosion coating composition that can be applied directly to rusted surfaces, has good corrosion resistance and adhesion, and can form a coating film with excellent flexibility. .

The present invention for achieving the above object is an anticorrosive coating composition containing (A) an epoxy resin, (B) an amine curing agent, (C) reactive butadiene acrylonitrile and (D) magnesium oxide, wherein the (D) Magnesium oxide has a BET specific surface area of 3.0 m ² /g or more, and the content of (D) magnesium oxide is 5 to 15% by mass based on the solid content.

The anticorrosive coating composition preferably further contains (E) a non-reactive diluent, and the (E) non-reactive diluent preferably contains a liquid hydrocarbon resin.

The (A) epoxy resin is preferably liquid at a temperature of 15 to 25°C.
In the anticorrosive coating composition, the (B) amine curing agent preferably contains (b1) phenalkamine and (b2) polyamidoamine.

The anticorrosive coating composition preferably further contains at least one selected from (F) a reactive diluent and (G) a silane coupling agent.

The (C) reactive butadiene acrylonitrile preferably contains a functional group that reacts with an epoxy group at its terminal.

The anticorrosive coating composition can be suitably used for rusted surfaces.

Another invention for achieving the above object is an anticorrosion coating film formed from the anticorrosion coating composition.

Another invention for achieving the above object is a substrate with an anticorrosive coating comprising the anticorrosive coating and a substrate.

As the base material with the anticorrosion coating film, it is preferable that the base material has a rusted surface, and the anticorrosion coating film is in direct contact with the rusted surface of the base material.

Another invention for achieving the above object is a method for producing a base material with an anticorrosive coating, comprising the following steps [1] and [2].
[1] A step of coating a substrate with the anticorrosive coating composition.
[2] A step of drying the coated anticorrosive coating composition to form a coating film.

The anticorrosive coating composition of the present invention can be applied directly to a rusted surface, and can form a coating film having good anticorrosive properties and adhesion and excellent flexibility.

The anticorrosive coating composition of the present invention contains (A) an epoxy resin, (B) an amine curing agent, (C) a reactive butadiene acrylonitrile and (D) magnesium oxide, and further contains (E) a non-reactive diluent. preferably.

<(A) Epoxy resin>
(A) Epoxy resin is preferably liquid at normal temperature (15 to 25° C.) and preferably has a viscosity in the range of 800 to 25,000 mPa·s. Such epoxy resins (A) include polymers or oligomers containing two or more epoxy groups in the molecule, and polymers or oligomers produced by ring-opening reaction of the epoxy groups. With such an epoxy resin (A), the effect of further improving the permeability into the interior of the rust can be obtained.

Examples of such liquid epoxy resins (A) include bisphenol-type epoxy resins, glycidyl ester-type epoxy resins, glycidylamine-type epoxy resins, phenol novolac-type epoxy resins, cresol-type epoxy resins, dimer acid-modified epoxy resins, and aliphatic epoxies. Epoxy resins such as resins, alicyclic epoxy resins, and epoxidized oil-based epoxy resins can be used. Among them, bisphenol type epoxy resins are preferred, bisphenol A type and F type epoxy resins are more preferred, and bisphenol A type epoxy resins are particularly preferred. By using a bisphenol type epoxy resin, it is possible to form a coating film having excellent adhesion to substrates and corrosion resistance.
Among such epoxy resins (A), so-called bisphenol A type epoxy resins (epoxy equivalent weight: 150 to 1000 (g/equiv)) are preferred.

Particularly preferably used bisphenol A type epoxy resins include, for example, bisphenol A diglycidyl ether, bisphenol A polypropylene oxide diglycidyl ether, bisphenol A ethylene oxide diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol A propylene oxide di Condensation products such as bisphenol A-type diglycidyl ether such as glycidyl ether can be mentioned.

In the present invention, (A) the epoxy resin can be used singly or in combination of two or more. When two or more epoxy resins (A) are used in combination as described above, the molecular weight and epoxy equivalent (g/equiv) of the epoxy resin (A) are both represented by their average values.

(A) The average molecular weight of the epoxy resin is not unconditionally determined depending on the coating curing conditions of the paint to be obtained (eg, normal dry coating, baking coating, etc.), but the molecular weight is usually 300 to 750, When the viscosity is 9,000 to 23,000 mPa·s and the epoxy equivalent is usually in the range of 150 to 300, a coating film having excellent coating workability, adhesion to substrates, water resistance, and corrosion resistance is formed. It is preferable because it can

A representative (A) epoxy resin is "Epikote 828 (trade name), general name: bisphenol A diglycidyl ether" (manufactured by Shell Co., Ltd., weight average molecular weight of about 360, epoxy equivalent of 180 to 190, viscosity of 12, 000 to 15,000 mPa · s / 25 ° C.), "Epotato YDF-170 (trade name), general name: bisphenol F diglycidyl ether" (manufactured by Tohto Kasei Co., Ltd., epoxy equivalent 160 to 180, viscosity 2,000 to 5,000 mPa·s/25°C), and "FLEP 60 (trade name)" (manufactured by Toray Thiocol Co., Ltd., epoxy equivalent: about 280, viscosity: about 17,000 mPa·s/25°C).

In the present invention, even an epoxy resin that is semi-solid at room temperature can be used as a liquid by diluting it appropriately.
As an epoxy resin that is semi-solid at room temperature, "Epikote 834 (trade name), general name: bisphenol A type epoxy resin" (manufactured by Japan Epoxy Resin Co., Ltd., epoxy equivalent 230 to 270, viscosity P by Gardner/Holtz method ~U/25°C).

In the anticorrosive coating composition of the present invention, the content of (A) the epoxy resin is usually 5 to 40% by mass, preferably 10 to 30% by mass, based on the solid content of the anticorrosive coating composition. By including (A) the epoxy resin in the above amount in the anticorrosive coating composition of the present invention, it is possible to form a coating film excellent in adhesion to substrates, water resistance and anticorrosion properties.

The solid content of the anticorrosive coating composition of the present invention is the mass percentage of the coating film (heated residue) after sufficiently reactively curing (heating) the anticorrosive coating composition, or the coating film (heated residue) itself. means. According to JIS K 5601-1-2, the solid content is obtained by weighing 1 ± 0.1 g of the anticorrosive coating composition (for example, the composition immediately after mixing the main component and the curing agent component) into a flat-bottomed dish and measuring a known mass. Spread it evenly with a wire, dry it at 23°C for 24 hours, and then heat it at a heating temperature of 110°C for 1 hour (under normal pressure). can be done. This solid content is equivalent to the total solid content (components other than the solvent) of the raw material components used in the anticorrosive coating composition of the present invention.

<(B) Amine Curing Agent>
The (B) amine curing agent is not particularly limited, but preferably includes (b1) phenalkamine, (b2) polyamidoamine, and polyetheramine, and (b1) phenalkamine and (b2) polyamidoamine It is particularly suitable. Since (b1) phenalkamine easily permeates into rust, the use of (b1) phenalkamine as a curing agent provides a paint exhibiting good adhesion even to rusted surfaces. However, since (b1) phenalkamine is a low-molecular-weight compound, its use alone may reduce the elongation of the coating film. Therefore, when (b1) phenalkamine is used, it is preferable to use (b2) polyamidoamine together. (b2) When polyamidoamine is contained, a tough coating film having flexibility is formed on the rust, and a coating film that suppresses cracking and peeling can be obtained even if the substrate is in a poor state. Polyetheramine also improves the penetration into the rust.

(b1) Phenalkamine is an epoxy curing agent composed of cardanol, formaldehyde and an organic diamine. Cardanol is prepared from cashew nut shell liquid (CNSL). Phenalkamine can be prepared by Mannich reaction to prepare a low molecular weight polymer by condensing 1 mol of alkylphenol, 2 mol of formaldehyde and 2 mol of polyamine. The polyamine can be aromatic or aliphatic.

(b1) Commercially available products containing phenalkamine include Cardolite NC-540 (manufactured by Cardolite), Cardolite NC-541 (manufactured by Cardolite), Ultra Lite 2009 (manufactured by Air Products), and phenalkamine, which are single products of phenalkamine. Ancamine 2792 (manufactured by Air Products Co., Ltd.), which is a mixture of polyether amine, and the like.

(b2) Polyamidoamine includes those produced mainly by condensation of dimer acid and polyamine and having reactive primary and secondary amino groups in the molecule. The molecular weight, viscosity, amine value, etc. of polyamidoamine vary depending on the monomer acid/dimer acid/trimer acid ratio, the type of polymer, and the number of functional groups.

(b2) Examples of commercially available polyamidoamines include Ankamide (R) 2353 (modified alicyclic polyamidoamine, manufactured by Air Products) and Ankamide (R) 2396A (modified alicyclic polyamidoamine, manufactured by Air Products). Tomide (R) 210 (amine value 100, semi-solid), Tomide (R) 215X (amine value 220, viscosity: 500 to 700 poise / 40 ° C.), Tomide (R) 225X (amine value 300, 80 to 120 poise /40°C), Tomide (R) 2500 (amine value 330, 5 to 10 poise/25°C), Tomide (R) 213A (polyamide adduct, amine value 85, xylene/butanol 50% solution), Tomide (R) 238 (Polyamide adduct, amine value 230, xylene/butanol 75% solution) and other Tomide series (manufactured by Fuji Kasei Co., Ltd.); 240), Versamide (R) 125 (amine value 345, 75 to 100 poise/40°C), Versamide (R) 230 (polyamide adduct, amine value 125, xylene/butanol 60% solution), etc. , Henkel Hakusui); Zenamide series such as Zenamide (R) 250 (amine value 440, 5 to 10 poise/25°C), Zenamid (R) 2000 (amine value 600, 10 to 25 poise/25°C), etc. Above, manufactured by Henkel Japan); Laccamide (R) N-153 IM 65 (amine value 100, xylene/butanol 65% solution), Laccamide (R) TD966 (amine value 170, xylene/butanol 60% solution), Laccamide ( R) Laccamide series such as TD973 (polyamine adduct, amine value 170, xylene/butanol 60% solution) (manufactured by Dainippon Ink Co., Ltd.); Sunmide (R) 300 (amine value 90, semisolid), Sunmide (R ) 306 (amine value 210, 500 to 700 poise / 40 ° C.), Sunmide (R) 316 (amine value 310, 90 to 110 poise / 40 ° C.), Sunmide (R) X-2000 (amine value 400, 10 to 30 Poise/25°C), Sunmide (R) X-2282 (amine value: 150, 4 to 9 poise/25°C) and other Sunmide series (manufactured by Sanwa Kagaku Co., Ltd.); Polymide (R) L-10-3 (amine value 100, semi-solid), Polymide (R) L-55-3 (amine value 380, 9.5 to 25.5 poise/20°C), etc. (manufactured by Sanyo Kasei Co., Ltd.); is mentioned. Further, polyamidoamines obtained by modifying polyoxyalkylene polyamines with polycarboxylic acids include, for example, Ancamamide (R) 910 (manufactured by Air Products Co., Ltd.), which is polyamidoamines obtained by modifying diethylene glycol diaminopropyl ether with dimer acid. (R) in the above product name indicates a registered trademark or the like.

Copolyamides obtained by polycondensation using two or more of the above polyamide-forming amines or acids, and polyamideimides (reaction products of trimellitic anhydride and aromatic diamines) may also be used.

These polyamidoamines may be used singly or in combination of two or more.
These polyamidoamine curing agents are available from N.I. V. When it is adjusted to 50 to 100% and the viscosity measured with an E-type viscometer at that time is in the range of 100 to 100,000 cPs, preferably 500 to 10,000 cPs, the handleability and coatability are excellent.

Further, among such (b2) polyamidoamines, it is preferable to use a modified alicyclic polyamidoamine from the viewpoint of application adhesion to rusted surfaces. From the viewpoint of imparting flexibility to the coating film, it is more preferable to use a polyamidoamine obtained by modifying a polyoxyalkylenepolyamine with a polycarboxylic acid.

Examples of the modified alicyclic polyamidoamine include Ankamide (R) 2353 and Ankamide (R) 2396A. Examples of polyamidoamines obtained by modifying polyoxyalkylene polyamines with polycarboxylic acids include Ankamide (R) 910, which is polyamidoamines obtained by modifying the diethylene glycol diaminopropyl ether with dimer acid.

(b2) When a curing agent having a molecular weight larger than that of polyamine is used as the polyamidoamine, it is possible to obtain an anticorrosion coating composition excellent in low-temperature curability.
Examples of the polyetheramine include compounds represented by the following structural formula (1).

（式中、Ｒ¹は、水素原子、メチル基、エチル基、プロピル基、またはｔ－ブチル基であり、Ｒ²は独立に、エチレン基、１，２－プロピレン基、２，３－プロピレン基、１，３－プロピレン基であり、Ｒ³はメチレン基、エチレン基、１，２－プロピレン基、２，３－プロピレン基、１，３－プロピレン基であり、ｎは繰り返し単位の平均値を意味し、２～１００である。）

(In the formula, R ¹ is a hydrogen atom, methyl group, ethyl group, propyl group, or t-butyl group, R ² is independently an ethylene group, 1,2-propylene group, 2,3-propylene group , 1,3-propylene group, R ³ is methylene group, ethylene group, 1,2-propylene group, 2,3-propylene group, 1,3-propylene group, n is the average value of repeating units means 2 to 100.)

The weight-average molecular weight (Mw) of the polyetheramine is preferably 300 to 5,000, more preferably 400, from the viewpoint that a composition having excellent storage stability and anticorrosion properties can be easily obtained. ~1,500.

Commercially available products may be used as the polyetheramine, and examples of such commercial products include “Jeffamine D-230”, “Jeffamine D-400”, “Jeffamine M-600”, “Jeffamine M-1000" and "Jeffamine M-2005" (both manufactured by Huntsman).

In the anticorrosive coating composition of the present invention, the content of (B) the amine curing agent is usually 5 to 30% by mass, preferably 8 to 20% by mass, based on the solid content of the anticorrosive coating composition. By including (B) the amine curing agent in the above amount in the anticorrosion coating composition of the present invention, a coating having good adhesion can be obtained.

In addition to (b1) phenalkamine and (b2) polyamidoamine, conventionally known amine curing agents, for example, polyamine compounds generally used as epoxy resin curing agents, as long as they do not impair the effects of the present invention. For example, aliphatic polyamines, modified aliphatic polyamines, alicyclic polyamines, modified alicyclic polyamines, aromatic polyamines, modified aromatic polyamines, etc. may be used in combination.
Moreover, dicyandiamide etc. are mentioned as a thermal latent hardening agent.

<(C) Reactive butadiene acrylonitrile>
(C) Reactive butadiene acrylonitrile imparts flexibility and softness to the coating film and improves crack resistance of the coating film. Therefore, when the anticorrosive coating composition of the present invention is directly applied to a rusted surface, the coating film can be accurately adhered to the rusted surface, and a flexible and tough coating film is formed on the rust, resulting in poor quality. Cracking and peeling can be suppressed even in the bare state. In addition, since it is incorporated into the structural framework of the coating film during the reaction curing process, it is possible to reduce the drawback of impairing water resistance, which is a problem in coatings blended with non-reactive rubber components.

Examples of (C) reactive butadiene acrylonitrile include those having an acrylonitrile polybutadiene skeleton in the main chain and functional groups that react with epoxy groups such as amino groups, carboxyl groups, and hydroxyl groups at the terminals.

Examples of such (C) reactive butadiene acrylonitrile include Hypro (R) ATBN 1300X16 (manufactured by CVC THERMOSET SPECIALITIES) and "Hypro (R) ATBN 1300 x 42 (manufactured by CVC THERMOSET SPECIALITIES), which have an amino group at the end. ), and Hypro(R) CTBN 1300X8 (manufactured by CVC THERMOSET SPECIALITIES) and Hypro(R) CTBN1300X31 (manufactured by CVCTHERMOSET SPECIALITIES) having a carboxyl group at the end.

A preferred type of such (C) reactive butadiene acrylonitrile comprises structural units selected from formulas (Ia)-(Id) below and terminal groups selected from formulas (IIa)-(IId) below.

（式中、Ｒａ は水素原子またはメチル基を表し、Ｒｂ は－ＣＯＯＨ、－ＣＯＯＲｃ または－ＣＯＮＨ₂を表し、Ｒｃは脂肪族基、好ましくはメチル基を表す。）

(In the formula, Ra represents a hydrogen atom or a methyl group, Rb represents -COOH, -COORc or _-CONH2 , and Rc represents an aliphatic group, preferably a methyl group.)

（式中、Ｒはアルキレン基を表す。）

(Wherein, R represents an alkylene group.)

The proportion of structural units of formulas (Ia), (Ib) and (Ic) is preferably 5 to 50% by weight, and the proportion of structural units of formula (Id) is preferably 0 to 30% by weight. .

In the anticorrosive coating composition of the present invention, the content of (C) reactive butadiene acrylonitrile is usually 0.1 to 2.0% by mass, preferably 0.2 to 1.0, based on the solid content of the anticorrosive coating composition. % by mass. By including (C) reactive butadiene acrylonitrile in the above-mentioned amount in the anticorrosion coating composition of the present invention, coating workability is improved and flexibility is imparted to the coating film.

<(D) Magnesium oxide>
(D) Magnesium oxide (MgO) suppresses corrosion at the lower part of the coating film and at the defective part of the coating film by continuously eluting the corrosion-inhibiting factor, and provides an anticorrosion coating composition with excellent rust prevention properties over a long period of time. to give Furthermore, it imparts excellent moisture resistance to the coating film. In addition, once a coating film is formed on an iron surface (steel material), when the anticorrosive coating composition of the present invention is directly coated on the surface where rust has occurred, (D) magnesium oxide is a trace amount of water remaining on the old coating film (MgO+H ₂ O→Mg(OH) ₂ ) and traps water, preventing rust from eroding the iron surface (steel material).

(D) Magnesium oxide has a BET specific surface area of 3.0 m ² /g or more, preferably 10 m ² /g or more, more preferably 30 m ² /g or more. Although the upper limit of the BET specific surface area is not particularly limited, it is, for example, 300 m ² /g. When the BET specific surface area is 3.0 m ² /g or more, the activity of magnesium oxide is high, the elongation of rust can be stopped rapidly, and even when the anticorrosive coating composition is directly applied to the rusted surface, excellent anticorrosion is obtained. demonstrate sexuality.

The BET specific surface area of magnesium oxide can be adjusted by the calcination temperature when producing magnesium oxide.
In this specification, the BET specific surface area can be measured using, for example, an automatic specific surface area measuring device Gemini VII23900 (manufactured by Shimadzu Corporation).

In the anticorrosion coating composition of the present invention, the content of (D) magnesium oxide is 5 to 15% by mass, preferably 6 to 14% by mass, more preferably 8 to 12%, based on the solid content of the anticorrosion coating composition. % by mass. (D) By containing magnesium oxide in the above amount in the anticorrosion paint composition of the present invention, excellent anticorrosion properties are obtained, and excellent anticorrosion properties are obtained even when the anticorrosion paint composition is directly applied to a rusted surface. Demonstrate.

<(E) Non-reactive diluent>
(E) A non-reactive diluent is a component that does not have reactivity in the anticorrosion coating composition and plays the role of a plasticizer. (E) The non-reactive diluent has the function of improving the flexibility of the coating film. Moreover, it has the function of suppressing the expansion of rust by improving the permeability of the anticorrosion coating composition into the rust and covering the surface of the rust. Since (E) the non-reactive diluent has a low viscosity, it is also possible to make the paint highly solid.

(E) As the non-reactive diluent, a liquid hydrocarbon resin that is liquid at room temperature (temperature of 15 to 25°C) and has a viscosity in the range of 500 to 400,000 mPa·s/25°C is suitable. Specifically, cardanol, its derivatives, and xylene resin can be preferably used.

In this case, the cardanol derivative (excluding the amine curing agent (B)) is added to the hydroxyl group, unsaturated aliphatic side chain or benzene ring in cardanol prepared from cashew nut shell liquid (CNSL), to the epoxy group or to the amino group. It refers to a compound formed by modifying a functional group that is non-reactive with

Commercial products of cardanol and its derivatives include LITE 2020 (manufactured by Cardolite) and NX-2024 (manufactured by Cardolite). , Nikanol L (manufactured by Fudo Co., Ltd.), Nikanol H (manufactured by Fudo Co., Ltd.), and the like.

In the anticorrosion coating composition of the present invention, the content of (E) non-reactive diluent is usually 0.1 to 10.0% by mass, preferably 0.5 to 5.0% by mass, based on the solid content of the anticorrosion coating composition. It is 0% by mass. By containing (E) the non-reactive diluent in the above amount in the anticorrosion coating composition of the present invention, it is possible to effectively suppress the spread of rust.

<Optional component>
The anticorrosive coating composition of the present invention may further contain (F) a reactive diluent, (G) a silane coupling agent, a tertiary amine, a pigment, a solvent, etc. as optional components.

(F) Reactive diluents include, for example, phenyl glycidyl ether, alkyl glycidyl ether (alkyl group having 1 to 15 carbon atoms, preferably 11 to 15 carbon atoms), versatic acid, glycidyl ester (R ₁ R ₂ R ₃ C—COO—Gly, R ₁ +R ₂ +R ₃ =C8-C10 alkyl group, Gly: glycidyl group), α-olefin epoxide (CH ₃ —(CH ₂ )n-Gly, n=11-13 , Gly: same as above), 1,6-hexanediol diglycidyl ether (Gly-O-(CH ₂ ) ₆ -O-Gly, Gly: same as above), neopentyl glycol diglycidyl ether (Gly-O-CH ₂ -C (CH ₃ ) ₂ —CH ₂ —O—Gly, Gly: same as above), trimethylolpropane triglycidyl ether (CH ₃ —CH ₂ —C(CH ₂ —O—Gly) ₃ , Gly: same as above), alkylphenylglycidyl Examples thereof include reactive diluents having an epoxy group such as ethers (alkyl group having 1 to 20 carbon atoms, preferably 1 to 5 carbon atoms, eg methylphenyl glycidyl ether, ethylphenyl glycidyl ether, propylphenyl glycidyl ether).

Among these (F) reactive diluents, monofunctional phenyl glycidyl ether, alkyl glycidyl ether, and alkyl phenyl glycidyl ether have low viscosity, so they are excellent in diluting effect (lowering the viscosity of paint) and high Can be solidified.

(F) Reactive diluents can be used singly or in combination of two or more. Examples of such reactive diluents include Epodil 759 (manufactured by Air Products Co., Ltd., alkyl (C12-C13) glycidyl ether, epoxy equivalent weight 285, non-volatile content 100%), Cardolite 2513HP (manufactured by Cardolite, alkylphenol glycidyl ether, epoxy equivalent of 400, non-volatile content of 100%) and the like.

(G) The silane coupling agent improves the penetration of the anticorrosion coating composition into rust. (G) The silane coupling agent usually has two functional groups in the same molecule and can contribute to improvement of adhesion to inorganic substrates and reduction of paint viscosity. ) is represented by ₃ . In the formula, X represents a functional group or an alkyl group capable of reacting with an organic substance. Examples of the functional group capable of reacting with the organic substance include an amino group, a vinyl group, an epoxy group, a mercapto group, a halogen group, and a hydrocarbon group containing these groups, or a hydrocarbon group with an ether bond interposed in the hydrocarbon group. and a group formed by addition to a group. OR represents a hydrolyzable group such as a methoxy group and an ethoxy group.

Specific examples of such (G) silane coupling agents include Silicone KBM-403 (γ-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.), Silane S-510 (Chisso Corporation ) made) and the like.
Such (G) silane coupling agent is desirably contained in the anticorrosive coating composition (solid content) in an amount of 0.5 to 5.0% by mass, and 1.0 to 3.0% by mass. It is more desirable to contain the amount of

If the anticorrosive coating composition of the present invention contains a tertiary amine, it is preferable in that curing is accelerated. Tertiary amines are specifically triethanolamine (N(C ₂ H ₅ OH) ₃ ), dialkylaminoethanol {[CH ₃ (CH ₂ ) _n ] ₂ NC ₂ H ₅ OH, n: number of repetitions }, triethylenediamine [1,4-diazacyclo(2,2,2)octane], 2,4,6-tri(dimethylaminomethyl)phenol {[CH ₂ N(CH ₃ ) ₂ ] ₃ —C ₆ H ₅ OH}, Versamin (R) EH30 (manufactured by Henkel Hakusui Co., Ltd.), and Ancamine (R) K-54 (manufactured by Air Products).

The tertiary amine is preferably contained in the anticorrosion paint composition (solid content) in an amount of 0.1 to 3.0% by mass, more preferably 0.2 to 1.0% by mass.
The pigment is not particularly limited, and known coloring pigments, extender pigments, antirust pigments, and the like can be used. Pigments are categorized into spherical, acicular, fibrous, etc., depending on their shape, and are generally classified according to the difference in aspect ratio, which is the ratio of the major axis to the minor axis of the particles.

Examples of coloring pigments include inorganic pigments such as carbon black, titanium dioxide, red iron oxide, iron oxide, iron hydroxide and ultramarine blue, and organic pigments such as cyanine blue and cyanine green. Color pigments can be used singly or in combination of two or more.

Extender pigments include, for example, calcium carbonate, potassium feldspar, kaolin, clay, talc, bentonite, magnesium carbonate, fine silica powder, barium arsenide sulfate, wollastonite, mica powder, glass flakes, and aluminum flakes. Among them, calcium calcium carbonate, talc, potassium feldspar, barium arsenide sulfate, and the like are preferable. Extender pigments can be used singly or in combination of two or more.

Examples of rust-preventive pigments include, but are not limited to, zinc powder, zinc alloy powder, zinc phosphate-based compound, calcium phosphate-based compound, aluminum phosphate-based compound, magnesium phosphate-based compound, zinc phosphite-based compound, and calcium phosphite-based compound. compound, aluminum phosphite-based compound, strontium phosphite-based compound, aluminum tripolyphosphate-based compound, molybdate-based compound, zinc cyanamide-based compound, borate compound, nitro compound, and composite oxide. It can be used alone or in combination of two or more.

Coloring pigments, extender pigments, and antirust pigments may be used in any combination. Such a pigment is desirably contained in the anticorrosion paint composition (solid content) in an amount of 25 to 80% by mass, more preferably 30 to 70% by mass.

In the anticorrosive coating composition of the present invention, if necessary, a pigment dispersant, a leveling agent, an anti-sagging agent, an antifoaming agent, and the like can be used to help disperse the pigment. They are not particularly limited, and conventionally known ones can be used.

The solvent is not particularly limited, and can be appropriately selected and used according to the coating workability of the anticorrosive coating composition according to the present invention. Solvents such as xylene, toluene, MIBK (methyl isobutyl ketone), 1-methoxy-2-propanol, MEK (methyl ethyl ketone), butyl acetate, n-butanol, iso-butanol, IPA (isopropyl alcohol), mineral spirits, solvent Naphtha (petroleum fraction), light aromatics, and the like can be mentioned, and these solvents are used alone or in combination of two or more.

≪Anticorrosion paint composition≫
The anticorrosive coating composition of the present invention can be prepared by mixing the above components.
The anticorrosive coating composition of the present invention contains (A) an epoxy resin, (B) an amine curing agent, (C) reactive butadiene acrylonitrile and (D) magnesium oxide, and the content of (D) magnesium oxide is solids 5 to 15% by mass of the medium, and preferably further containing (E) a non-reactive diluent, so that even a steel material part where rust occurs, it penetrates into the rust and further provides flexibility on the rust. It is possible to form a tough coating film with.
Therefore, the anticorrosive coating composition of the present invention can be suitably used for rusted surfaces.

≪Anti-corrosion coating, base material with anti-corrosion coating≫
The anticorrosive coating film according to the present invention (hereinafter also referred to as “main coating film”) is formed using the anticorrosive coating composition, and the substrate with anticorrosive coating film according to the present invention (hereinafter “substrate with main coating film”) ”) is a laminate having the present coating film and a substrate.

The material of the base material is not particularly limited, and examples include iron and steel (iron, steel, ferroalloy, carbon steel, mild steel, alloy steel, etc.), non-ferrous metals (zinc, aluminum, copper, brass, zinc plating, zinc spraying etc.), and stainless steel (SUS304, SUS410, etc.).

In addition, for example, when mild steel (SS400, etc.) is used as the substrate, if necessary, the surface of the substrate is polished by grit blasting, etc. to adjust the substrate (eg, arithmetic mean roughness (Ra) is 30 to 75 μm It is desirable to adjust the

Further, the base material may be a base material which has undergone a pretreatment such as cleaning treatment or blasting treatment to remove rust, dirt, paint (old coating film), etc. adhering to the base material. In addition, the anticorrosion coating composition of the present invention does not need to completely remove rust after removing the old coating film adhering to the substrate, and can be directly coated on the surface of the substrate such as steel materials where rust remains. It is possible.

As described above, even when the old coating film remains on the substrate or rust is generated, the anticorrosive coating composition of the present invention comprises the above (A) epoxy resin, (B) amine By containing a curing agent, (C) reactive butadiene acrylonitrile and (D) magnesium oxide, for example, the coating film can be formed without peeling (removing) the old coating film or removing the rust. This coating film can also provide the effects described above.

The substrate is not particularly limited, and can be used without limitation for substrates that require anticorrosive properties. Examples include (steel) structures such as ships, offshore structures, plants, bridges, tanks, and containers.

Although the dry film thickness of the present coating film is not particularly limited, it is usually 10 to 150 μm, preferably 20 to 120 μm, more preferably 30 to 100 μm from the viewpoint of obtaining a coating film having sufficient anticorrosion properties.

The substrate with this coating film is a laminate containing this coating film and the substrate, and on this coating film, an intermediate coating film for the purpose of further improving corrosion resistance, weather resistance and aesthetics etc. An excellent topcoat film may be formed. Examples of the intermediate coating film include coating films formed from various intermediate coating compositions such as acrylic resin-based, epoxy resin-based, and urethane resin-based intermediate coating compositions. Examples of the topcoat film include coating films formed from various topcoat paint compositions such as acrylic resin-based, acrylic silicone resin-based, urethane resin-based, silicone resin-based, and fluororesin-based topcoat paint compositions.

≪Method for producing substrate with coating film≫
The method for producing a substrate with an anticorrosion coating film according to the present invention (hereinafter also referred to as "this method") includes the following steps [1] and [2].
Step [1]: Step of applying the anticorrosion coating composition to a substrate Step [2]: Step of drying the anticorrosion coating composition coated on the substrate to form an anticorrosion coating film

<Step [1]>
The coating method in step [1] is not particularly limited, and examples thereof include conventionally known methods such as spray coating such as airless spray coating and air spray coating, brush coating, and roller coating. Among these, spray coating is preferable from the viewpoint that it is possible to easily coat large-area substrates such as the structures described above.
At the time of such coating, it is preferable to coat so that the dry film thickness of the resulting coating film is within the above range.

The conditions of the spray coating may be appropriately adjusted according to the desired dry film thickness. For example, in the case of airless spray coating, primary (air) pressure: about 0.3 to 0.6 MPa, secondary (paint ) Pressure: preferably about 10 to 15 MPa, gun moving speed about 50 to 120 cm/sec.

When the anticorrosion coating composition is applied, the viscosity of the anticorrosion coating composition may be adjusted as desired.
In this case, it is preferable to use a diluent so that the paint viscosity is suitable for each coating method. to 30 parts by mass, more preferably 1 to 20 parts by mass.

The viscosity of the anticorrosive coating composition suitable for the spray coating (composition diluted if necessary) was measured at 23 ° C. using a B-type viscometer (manufactured by Rion Co., Ltd., model VT-06) as a measuring instrument. Viscosity under measurement conditions is preferably 1,000 to 10,000 mPa·s, more preferably 2,000 to 8,000 mPa·s.

<Step [2]>
The drying conditions in the step [2] are not particularly limited, and may be appropriately set according to the method of forming the coating film, the type of substrate, the application, the coating environment, etc. However, the drying temperature is normal temperature drying. , usually 5 to 40°C, more preferably 10 to 30°C.

The drying time may be about 1 to 7 days as with conventional paints, but the anticorrosive paint composition preferably dries in 3 to 16 hours, more preferably 5 to 12 hours. can be made

[Examples 1 to 15, Comparative Examples 1 to 8]
The raw materials shown in Table 1 were mixed and stirred with a disper in the amounts shown in Table 1 to obtain an anticorrosion coating composition. The numerical values shown in Table 1 represent parts by mass.
The obtained anticorrosive coating composition was subjected to the following tests. Table 2 shows the test results. In addition, Table 3 summarizes the raw materials used in Examples and Comparative Examples.

<Corrosion resistance test>
A cycle corrosion test was conducted in accordance with JIS K 5600-7-9 "Cycle Corrosion Test Method".

As the test plate, a corroded steel plate with a rust thickness of 40 to 50 μm, which was prepared by exposing an uncoated steel plate to the outdoors for one year, was used. After surface treatment of the construction surface with sandpaper (#180), the construction surface is washed with a waste cloth, and within 30 minutes after washing, the anticorrosive paint composition is applied with a brush so that the dry film thickness is 100 μm, A specimen was obtained by curing under standard conditions. In accordance with 7.5 a) of JISK 5600-7-9, a notch (cut) was made on the obtained test plate to obtain a test plate.
The test machine conditions were JIS K 5600-7-9 Cycle D, and the test time was 2000 hours.

Visually observe the presence and degree of rust, blistering, rust, blistering, and rust liquid in the cut portion of the test plate after the test, and determine the corrosion resistance according to the following evaluation criteria. rice field.

Evaluation of rust and blistering in general parts ◯: No abnormalities such as rust and blistering on the coating film.
Δ: Abnormalities such as partial rust and blistering are present in the coating film.
x: Abnormalities such as rust and blistering are present on the entire surface of the coating film.

Evaluation of bulging at the cut portion ◯: The bulging width at the cut portion is 4 mm or less.
Δ: The swollen width of the cut portion is greater than 4 mm and 8 mm or less.
x: The swollen width of the cut portion is greater than 8 mm.

Evaluation of rust at the cut portion ◯: The width of rust at the cut portion is 4 mm or less.
Δ: The rust width of the cut portion is greater than 4 mm and 8 mm or less.
x: The rust width of the cut portion is greater than 8 mm.

Evaluation of rust juice at the cut portion ⊚: Almost no rust juice was generated from the cut portion.
◯: A small amount of rust juice is generated only from the edge of the cut portion.
Δ: A small amount of rust juice is generated from the entire cut portion.
x: A large amount of rust juice is generated from the entire cut portion.

<Adhesion test>
An adhesion test was carried out according to JIS K 5600-5-6 “Adhesion (cross-cut method)” on the same test plate used in the cyclic corrosion test.

Adhesiveness was determined according to the following evaluation criteria.
A: The peeled area is 3% or less.
○: The peeled area is more than 3% and 5% or less.
Δ: The peeled area is more than 5% and 15% or less.
x: Peeling area is greater than 15%.

<Tensile test>
The tensile test was performed according to the 6 crack follow-up test method of the quality test method for concrete paint materials described in "Handbook for Steel Highway Bridges".

The anticorrosion coating composition was applied to a polypropylene resin plate using an air spray so that the dry film thickness was 100 μm, cured at 23° C. for 120 hours, heated at 80° C. for 60 minutes, and allowed to cool. Next, the molded coating film was peeled off from the polypropylene resin plate to obtain a free coating film. A test piece was prepared from this free coating film using a puncher, and a tensile test was performed at a gauge distance of 40 mm and a test temperature of 23° C. to determine the elongation rate.

Elongation was determined according to the following evaluation criteria.
Good: The elongation rate is 5% or more.
Δ: The elongation rate is 3% or more and less than 5%.
x: The elongation rate is less than 3%.

Claims (12)

An anticorrosive coating composition containing (A) an epoxy resin, (B) an amine curing agent, (C) reactive butadiene acrylonitrile and (D) magnesium oxide, wherein the (D) magnesium oxide has a BET specific surface area of 3.5. 0 m ² /g or more, and the content of (D) magnesium oxide is 5 to 15% by mass based on the solid content. 2. The anticorrosive coating composition according to claim 1, further comprising (E) a non-reactive diluent. 3. The anticorrosion coating composition according to claim 2, wherein (E) the non-reactive diluent contains a liquid hydrocarbon resin. The anticorrosion coating composition according to any one of claims 1 to 3, wherein (A) the epoxy resin is liquid at a temperature of 15 to 25°C. 5. The anticorrosive coating composition according to any one of claims 1 to 4, wherein the (B) amine curing agent contains (b1) phenalkamine and (b2) polyamidoamine. 6. The anticorrosive coating composition according to any one of claims 1 to 5, further comprising at least one selected from (F) a reactive diluent and (G) a silane coupling agent. 7. The anticorrosive coating composition according to any one of claims 1 to 6, wherein (C) the reactive butadiene acrylonitrile contains a terminal functional group that reacts with an epoxy group. The anticorrosive coating composition according to any one of claims 1 to 7, which is for rusted surfaces. An anticorrosion coating film formed from the anticorrosion coating composition according to any one of claims 1 to 8. A substrate with an anticorrosive coating comprising the anticorrosive coating according to claim 9 and a substrate. The substrate with an anticorrosion coating according to claim 10, wherein the substrate is a substrate having a rusted surface, and the anticorrosion coating is in direct contact with the rusted surface of the substrate. A method for producing a substrate with an anticorrosive coating, comprising the following steps [1] and [2].
[1] A step of applying the anticorrosive coating composition according to any one of claims 1 to 7 to a substrate.
[2] A step of drying the coated anticorrosion coating composition to form an anticorrosion coating film.