JP7368938B2 - Water-based paint composition with excellent corrosion resistance - Google Patents

Description

The present invention relates to a water-based coating composition with excellent corrosion resistance and an anticorrosion coating method.

Steel materials are widely used in many fields such as marine structures, port facilities, ships, architecture, civil engineering structures, and automobiles, but there is a problem that they corrode when exposed to the natural environment. Anticorrosive coating is used as a method to prevent or suppress corrosion.

In recent years, steel structures such as iron bridges, plants, steel towers, and petroleum facilities have reached the age of deterioration and need to be renovated and painted.

In general, when repainting steel structures, it is important to prepare the surface before painting, and the accuracy of the preparation determines the lifespan of the paint film. Specific examples of surface treatment include removing rusted parts of steel structures, roughening the surface of old coatings, and removing coatings that have lost their antirust effect and become brittle. The degree of surface treatment is called "keren," and is classified by grade from type 1 to type 3, and surface treatment is performed using a treatment method depending on the grade. The classification of grades of keren is generally not clearly defined, but type 1 keren refers to full-scale surface treatment that completely removes rust and paint film and cleans the steel surface, while type 3 keren is a simple base treatment that leaves the active film and removes rust and deteriorated paint, and type 2 cleaning is in between.

In order to perform surface treatment to a Class 1 keren grade, which is considered ideal for repair painting of steel structures, there are blasting methods such as sandblasting and shotblasting, in which abrasive particles are sprayed with compressed air. The blasting method has problems such as mechanical noise, work noise, labor, and time required.

For example, if Type 1 grade is used for surface treatment, it is said that 60 to 70% of the cost required for the entire renovation painting work will be spent on blasting and industrial waste disposal costs, and if Grade 2 or Grade 3 is used, There has been a need for a corrosion-resistant repainting method that can provide long-term corrosion protection even with a simple surface treatment.

As such a measure, Patent Document 1 proposes a method for forming an anticorrosive film on a rust surface, in which a metal surface having a rust layer is coated with an epoxy resin paint containing a silane coupling agent. According to the description in Patent Document 1, the silane coupling agent contained in the epoxy resin paint can be fixed to the rust layer and the metal surface by the moisture in the rust layer, and even if rust remains on the metal surface, the silane coupling agent contained in the epoxy resin paint can be fixed. It is stated that an anticorrosive coating provided on a substrate can protect the substrate.

In addition, Patent Document 2 describes a technique for fixing a rust layer by using the moisture contained in the rust layer, which describes applying an epoxy resin paint using a ketimine compound as a hardening agent to a metal surface having a rust layer. A method of forming an anticorrosion coating on a rust surface has been proposed.

However, according to the methods of Patent Documents 1 and 2, rust remains on the base material, so sufficient quality in terms of corrosion resistance and adhesion is not yet obtained, and further improvements are required.

On the other hand, in recent years, water-based coatings have been increasingly used in the field of heavy duty anticorrosive coatings due to environmental considerations.

As a water-based heavy-duty anti-corrosion paint, for example, Patent Document 3 describes a two-component water-based anti-corrosion paint that includes a base agent containing an epoxy resin emulsion and an amine curing agent containing a cyclic polyamine having a specific active hydrogen equivalent. . Although the water-based anticorrosion paint can form a film with excellent corrosion resistance even if it is water-based, it may not have sufficient corrosion resistance when applied to a rusted surface or when exposed for a long time in harsh environments such as beaches. It was not possible to achieve the desired performance, and rust spots sometimes occurred on the surface of the paint film.

On the other hand, Patent Document 4 describes a water-based paint composition containing an amine-modified epoxy resin obtained by modifying an epoxy resin having a bisphenol skeleton with an amine compound and a water-insoluble compound with a boiling point of 200°C or higher as a plasticizer. has been done. According to Patent Document 4, it is stated that such a compound can be contained in an amine-modified epoxy resin to form a coating film, and that this can contribute to better corrosion resistance.

However, Patent Document 4 does not clearly state that it is a two-component composition. It is only stated that such a water-insoluble compound has a property of being compatible with the amine-modified epoxy resin, but there is no description of the manner in which the water-insoluble compound coexists with the crosslinking agent that is the reaction partner of the amine-modified epoxy resin. do not have.

Japanese Patent Application Publication No. 1-25877 Japanese Patent Publication No. 60-78672 Japanese Patent Application Publication No. 2009-149791 International publication WO2011-118790 pamphlet

An object of the present invention is to provide an aqueous coating composition and an anticorrosive coating method that can form a good anticorrosive coating even when applied to a substrate with residual rust.

As a result of intensive studies regarding the above-mentioned problems, the present inventors have found that by incorporating a specific amount of softener into the side containing the resin emulsion with a low weight average molecular weight of the two-component water-based coating composition. It was discovered that a coating film that exhibits excellent anticorrosion properties can be obtained even on substrate surfaces where rust remains.

That is, the present invention includes the following aspects.
Item 1.
A first component (I) containing a resin emulsion (A), and a second component (II) containing a resin emulsion (B) and a softener (C), the weight average of the resin of the resin emulsion (B) The molecular weight is lower than the weight average molecular weight of the resin of the resin emulsion (A),
A two-component water-based coating composition containing a softener (C) in the second component (II) in an amount of 1 to 30% by mass.
Item 2.
Item 2. The aqueous coating composition according to item 1, wherein the resin emulsion (A) is an amino group-containing resin emulsion, and the resin emulsion (B) is an epoxy group-containing resin emulsion.
Item 3.
Item 3. The aqueous coating composition according to Item 1 or 2, wherein the resin emulsion (B) is an emulsion of a novolak-type epoxy resin.
Item 4.
4. The aqueous coating composition according to any one of Items 1 to 3, wherein the softener (C) contained in the second component (II) has a functional group capable of reacting with the resin of the resin emulsion (A).
Item 5.
Item 4. The water-based paint according to any one of Items 1 to 4, wherein the resin emulsion (A) contained in the first component (I) is a modified resin emulsion using a reactive group-containing softener (a4) as a raw material. Composition.
Item 6.
The first component (I) and/or the second component (II) further contain a rust preventive pigment component (D), and the rust preventive pigment component (D) contains magnesium ions, aluminum as part of its components. Any one of Items 1 to 5, comprising the anticorrosive pigment (d) that can elute at least one ion selected from ion, calcium ion, zinc ion, silicate ion, phosphate ion, vanadate ion, and molybdate ion. The aqueous coating composition according to item 1.
Section 7.
Item 7. The aqueous coating composition according to any one of Items 1 to 6, wherein the first component (I) and/or the second component (II) further contains a fibrous inorganic compound (E).
Section 8.
Item 8. The aqueous coating composition according to any one of Items 1 to 7, wherein the first component and/or the second component (II) further contains a polycarbodiimide compound (F).
Item 9.
Item 8. The aqueous coating composition according to any one of Items 1 to 8, wherein the first component and the second component both have a pH of 5.0 to 9.0.
Item 10.
An aqueous coating composition obtained by mixing the first component (I) and the second component (II) according to any one of Items 1 to 9.
Item 11.
An anticorrosive coating method comprising coating an object to be coated with the water-based coating composition according to item 10.
Item 12.
12. The anticorrosive coating method according to item 11, wherein the object to be coated is a base material surface on which rust remains.
Item 13.
A coated article coated with the anticorrosive coating according to item 11 or 12.

According to the water-based paint composition of the present invention, both the storage stability of the paint state before painting is good, and by mixing the two and painting, a paint film with excellent corrosion resistance can be obtained even under conditions of room temperature drying. This makes it possible to maintain the beauty of the coated object for a long period of time even if it is exposed to harsh environments such as beaches for a long period of time.

Further, the water-based coating composition of the present invention can exhibit sufficient anticorrosion properties even when directly applied to a newly installed base material as well as a base material with residual rust. For this reason, it can be applied to repaint aging steel structures with residual rust, and in addition to being environmentally friendly as it is a water-based composition, it can significantly reduce the total labor required for painting. .

The two-component aqueous coating composition of the present invention comprises a first component (I) containing a resin emulsion (A) and a second component (II) containing a resin emulsion (B).

<Resin emulsion (A)>
In the present invention, the resin emulsion (A), which can serve as a coating film-forming component together with the resin emulsion (B) described below, is an aqueous dispersion obtained by dispersing a synthetic resin capable of forming a coating film in water. There are no particular restrictions on the synthetic resins used for resin emulsion (A) and resin emulsion (B), and those known in the paint field can be used, but preferably, resin emulsion (A) and resin emulsion (B) are It is preferable that each of them has functional groups that can react with each other.

Examples of the combinations of reactive functional groups contained in the resin emulsion (A) and the resin emulsion (B) include combinations of an acid group and an epoxy group, an amino group and an epoxy group, and a combination of a hydroxyl group and an isocyanate group. A combination of an epoxy group and an amino group is more preferable, and it is particularly preferable that the resin emulsion (A) is an amino group-containing resin emulsion and the resin emulsion (B) is an epoxy group-containing resin emulsion.

In the present invention, the resin emulsion (A) is suitably a resin made from an epoxy resin (a1) and a polyamine compound (a2) as raw materials, and the total amine value of the resin is in the range of 20 to 120 mgKOH/g. Inside is preferable.

《Epoxy resin (a1)》
The epoxy resin (a1) as a raw material for producing the resin emulsion (A) is a resin having at least one, preferably two or more, epoxy groups in the molecule, and has an epoxy group of at least 160, preferably within the range of 180 to 2,500. Suitable are those having an epoxy equivalent weight of .

Specifically, the epoxy resin (a1) includes bisphenol type epoxy resins such as bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol AD type epoxy resin; epoxy ester obtained by modifying the above bisphenol type epoxy resin with dibasic acid, etc. Resin: Novolac type epoxy resin such as cresol novolac type epoxy resin, phenol novolac type epoxy resin; Alicyclic epoxy resin; Polyglycol type epoxy resin; Hydrogenated bisphenol A type epoxy resin; Ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether , polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ether , aliphatic epoxy resins such as glycerin polyglycidyl ether, diglycerin polyglycidyl ether, and polyglycerin polyglycidyl ether, and epoxy group-containing acrylic resins whose constituent components are epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate. It will be done. As the epoxy resin, unmodified epoxy resin is preferable. These can be used alone or in combination of two or more.

Examples of commercially available epoxy resins (a1) include "jER827", "jER828", "jER828EL", "jER828XA", "jER834" (manufactured by Mitsubishi Chemical Corporation), "EPICLON840", and "EPICLON840-S". ”, “EPICLON850”, “EPICLON850-S”, “EPICLON850-CRP”, “EPICLON850-LC” (all manufactured by DIC), “Epototh YD-127”, “Epototh YD-128” (all manufactured by Toto Kasei Co., Ltd.) Bisphenol A type epoxy resins such as "Recaresin BPO-20E", "Recaresin BEO-60E" (manufactured by Shin Nippon Chemical Co., Ltd.); "jER806", "jER807" (manufactured by Mitsubishi Chemical Corporation), " Bisphenol F-type epoxy resins such as "EPICLON830", "EPICLON830-S", "EPICLON835" (manufactured by DIC Corporation), "Epotote YDF-170" (manufactured by Toto Kasei Corporation); "jER4250" (manufactured by Mitsubishi Chemical Corporation), etc. bisphenol A-type bisphenol F-type phenoxy resins, novolac type epoxy resins such as "jER152" (manufactured by Mitsubishi Chemical Corporation); water such as "Recaresin HBE-100" (manufactured by Shin Nihon Rika Co., Ltd.), "Denacol EX-252" (manufactured by Nagase ChemteX Co., Ltd.), "SR-HBA" (manufactured by Sakamoto Pharmaceutical Co., Ltd.), etc. Added bisphenol A type epoxy resin; "YED205", "YED216M", "YED216D" (manufactured by Mitsubishi Chemical Corporation), "Epototh YH-300", "Epototh YH-301", "Epototh YH-315", "Epototh YH-324'', ``Epototo YH-325'' (manufactured by Toto Kasei Co., Ltd.), ``Denacol EX-211'', ``Denacol EX-212'', ``Denacol EX-212L'', ``Denacol EX-214L'', ``Denacol EX-216L”, “Denacol EX-313”, “Denacol EX-314”, “Denacol EX-321”, “Denacol EX-321L”, “Denacol EX-411”, “Denacol EX-421”, “Denacol EX -512'', ``Denacol EX-521'', ``Denacol EX-611'', ``Denacol EX-612'', ``Denacol EX-614'', ``Denacol EX-614B'', ``Denacol EX-622'', ``Denacol EX- 810'', ``Denacol EX-811'', ``Denacol EX-850'', ``Denacol EX-850L'', ``Denacol EX-851'', ``Denacol EX-821'', ``Denacol EX-830'', ``Denacol EX-832'' ”, “Denacol EX-841”, “Denacol EX-861”, “Denacol EX-911”, “Denacol EX-941”, “Denacol EX-920”, “Denacol EX-931” (all manufactured by Nagase ChemteX) ), "SR-NPG", "SR-16H", "SR-16HL", "SR-TMP", "SR-PG", "SR-TPG", "SR-4PG", "SR-2EG", "SR-8EG", "SR-8EGS", "SR-GLG", "SR-DGE", "SR-DGE", "SR-4GL", "SR-4GLS", "SR-SEP" (the above, Examples include aliphatic epoxy resins such as those manufactured by Sakamoto Pharmaceutical Co., Ltd.).

The above-mentioned epoxy resin (a1) is produced by reacting the above-exemplified epoxy resin with difunctional polyester polyols, bifunctional polyether polyols, bisphenols, dibasic carboxylic acids, etc. so that an excess of epoxy groups is obtained. Also included are epoxy resins obtained by.

<<Polyamine compound (a2)>>
The polyamine compound (a2) is preferably a polyamine compound (a2-1) having primary amino groups at both ends of the molecule and at least one secondary amino group.

Examples of such polyamine compounds (a2-1) include dialkylene triamines such as dimethylene triamine, diethylene triamine, dipropylene triamine, dibutylene triamine, and bis(hexamethylene) triamine; triethylenetetramine, tripropylenetetramine, etc. Trialkylenetetramine; tetraalkylenepentamine such as tetraethylenepentamine and tetrapropylpentamine; pentaalkylenehexamine; hexaalkyleneheptamine, and the like. These can be used alone or in combination of two or more.

In particular, in the present invention, the polyamine compound (a2-1) is preferably dialkylene triamine from the viewpoint of production and storage stability of the first component (I) and corrosion resistance on rust surfaces, and has 2 to 2 carbon atoms. Particularly suitable are dialkylene triamines having 8, preferably 3 to 6 alkylene groups.

In addition, examples of polyamines that can be used other than the polyamine compound (a2-1) include monomethylamine, dimethylamine, monoethylamine, diethylamine, dipropylamine, dibutylamine, dihexylamine, dioctylamine, monoisopropylamine, and diisopropylamine. , mono- or di-alkylamines such as monobutylamine, monooctylamine, methylbutylamine, dibutylamine; monoethanolamine, N-methylethanolamine, N-ethylethanolamine, diethanolamine, mono(2-hydroxypropyl) Amine, di(2-hydroxypropyl)amine, N-butylethanolamine, dipropanolamine, monomethylaminoethanol, N-(2-hydroxypropyl)ethylenediamine, 3-methylamine-1,2-propanediol, 3-tert -Alkanolamines such as butylamino-1,2-propanediol, N-methylglucamine, N-octylglucamine; polymethylenediamine, polyetherdiamine, ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, trimethylhexamethylene alkylene polyamines such as diamine, dimethylaminopropylamine, diethylaminopropylamine, bis(4-aminobutyl)amine; Aromatic or alicyclic polyamines such as phenylene diamine, naphthylene diamine, and dimethylaminomethylbenzene; Polyamines having a heterocycle such as piperazine, 1-methylpiperazine, 3-pyrrolidinol, 3-piperidinol, and 4-pyrrolidinol; Epoxy-added polyamine obtained by adding an epoxy group-containing compound to 1 mole of polyamine; the above polyamine and aromatic acid anhydride, cyclic aliphatic acid anhydride, aliphatic acid anhydride, halogenated acid anhydride and/or Polyamide polyamine containing one or more primary or secondary amines in the molecule of polyamide resin produced by condensation with dimer acid; Reacting one or more primary or secondary amines in the above polyamine with a ketone compound and ketiminated amines. These can be used alone or in combination of two or more.

The ratio of the epoxy resin (a1) and the polyamine compound (a2) used is 0.2 to 3.0 mol, preferably 0.5 to 2.0 mol, of the polyamine compound (a2) per 1 mol of the epoxy resin (a1). Suitably, the proportion is 5 moles.

《Ketone compound (a3)》
Further, the resin emulsion (A) is preferably a resin whose production raw materials include a ketone compound (a3) in addition to an epoxy resin (a1) and a polyamine compound (a2).

Examples of the ketone compound (a3) include methyl isopropyl ketone, diisobutyl ketone, methyl isobutyl ketone, diethyl ketone, ethyl butyl ketone, ethylpropyl ketone, dipropyl ketone, and methyl ethyl ketone. These can be used alone or in combination of two or more. Among them, methyl isobutyl ketone is preferred.

When using the ketone compound (a3), the usage ratio in that case is 0.2 to 3.0 mol, preferably 0.5 to 2.0 mol, per 1 mol of the primary amino group in the amine compound (a2). Suitably, the proportion is 5 moles.

<<Reactive group-containing softener (a4)>>
Further, the resin emulsion (A) is suitably a reactive group-containing softener (a4) modified resin emulsion that uses the reactive group-containing softener (a4) as a raw material. The second component (II) described below contains a softener (C) and the functional groups contained in the resin emulsion (A) are partially reacted with the reactive group-containing softener (a4), so that the composition of the present invention can be obtained. It is effective in improving the anti-corrosion properties of coatings formed by materials.

The reactive group-containing softener (a4) may be a compound having an alkyl group having 4 or more carbon atoms and a functional group capable of reacting with a functional group contained in the resin emulsion (A).

When the resin emulsion (A) is an amino group-containing resin emulsion, the reactive group-containing softener (a4) can be a compound having a functional group such as a carboxyl group and/or a glycidyl group. Specific examples include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. Ether, trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ester, glycerin polyglycidyl ether, diglycerin polyglycidyl ether, polyglycerin polyglycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl Alkyl glycidyl ether compounds such as ether, cresyl glycidyl ether, tert-butylphenyl glycidyl ether;
Glycidyl butyrate, glycidyl stearate, glycidyl neodecanoate, epoxidized soybean oil, epoxybutyl stearate, di2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate, epoxy triglyceride, epoxidized octyl oleate, Alkyl glycidyl ester compounds such as epoxidized decyl oleate;
Coconut oil fatty acids, cottonseed oil fatty acids, hempseed oil fatty acids, rice bran oil fatty acids, fish oil fatty acids, tall oil fatty acids, soybean oil fatty acids, linseed oil fatty acids, tung oil fatty acids, rapeseed oil fatty acids, castor oil fatty acids, dehydrated castor oil fatty acids, safflower oil fatty acids long chain alkyl fatty acids such as; and the like.

When such a reactive group-containing softener (a4) is used as a manufacturing raw material, the ratio of use in that case is 1 mole of primary amino groups contained in the polyamine compound (a2). It is suitable that the amount of the functional group capable of reacting with the amino group to be used is in the range of 0.1 to 0.8 mol, preferably 0.2 to 0.6 mol.

Since the reaction ratio of the reactive group-containing softener (a4) to the polyamine compound (a2) is within the above range, the coating film formed from the aqueous coating composition of the present invention has excellent film-forming properties and excellent corrosion resistance. can demonstrate.

In the present invention, the resin emulsion (A) can be manufactured using the above-mentioned components (a1) and (a2) and, if necessary, (a3) and/or (a4), as well as surfactants, etc. Other components can be used as manufacturing raw materials as needed. The manufacturing method is not particularly limited, and the primary amino group of the polyamine compound (a2) is reacted with the ketone compound (a3) to form a ketimine, and then the secondary amino group and the epoxy group of the epoxy resin (a1) are reacted. Then, there is a production method in which ketimine is returned to a primary amino group by hydrolysis during dilution with water.

According to the above manufacturing method, the resin emulsion (A) can have a primary amino group, which is a water-dispersible group, at the resin end in the presence of water, and forms an anticorrosive coating film with excellent anticorrosion properties on rusted surfaces. Helpful.

The surfactants used as necessary are not particularly limited, and include, for example, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, sorbitan alkyl esters, Polyoxyethylene sorbitan alkyl esters, glycerin esters and their derivatives, alkylbenzene sulfonates, alkyl ether sulfates, alkenyl ether sulfates, alkyl sulfates, alkenyl sulfates, α-olefin sulfonates, α-sulfo fatty acids or Ester salt, alkanesulfonate, saturated fatty acid salt, unsaturated fatty acid salt, alkyl ether carboxylate, alkenyl ether carboxylate, amino acid type surfactant, N-acyl amino acid type surfactant, alkyl phosphate ester or its Anionic surfactants such as salts, alkenyl phosphate esters or their salts; Cationic surfactants such as quaternary ammonium salts; Ampholytic surfactants such as carboxyl type amphoteric surfactants and sulfobetaine type amphoteric surfactants. etc.

When blending the above-mentioned surfactant, it may be carried out not only at the resin production stage but also at any stage of the paint production process. From the viewpoint of storage stability in the paint state and corrosion resistance of the formed coating film, the blending amount is 1 to 15 parts by mass, based on 100 parts by mass of the total nonvolatile content of the resin emulsion (A) and the resin emulsion (B). In particular, a range of 3 to 8 parts by mass is suitable.

In this specification, the term "nonvolatile matter" refers to a residue after removing volatile components, and the residue may be solid or liquid at room temperature. For example, it refers to the components remaining after volatile components are removed by treating a sample at 105° C. for 3 hours.

In addition, when compound (a4) is used as a production raw material, it can be used at any stage in the production of resin emulsion (A), but the primary amino group at the end of polyamine compound (a2) can be replaced with a ketone compound ( After reacting with a3) to form a ketimine, the secondary amino group and the epoxy group of the epoxy resin (a1) are reacted, and then, when diluting with water, the ketimine is returned to a primary amine by hydrolysis, and then compound (a4) is converted into a ketimine. A method of reacting is preferred.

The resin emulsion (A) is well dispersed in an aqueous medium due to the presence of an optionally neutralized amino group. In the case of an aqueous dispersion, the average particle size is generally in the range of 50 to 500 nm, particularly 100 to 300 nm, from the viewpoint of film forming properties and curability when dried at room temperature.

Examples of neutralizing agents used for neutralization include formic acid, acetic acid, oxalic acid, malonic acid, succinic acid, malic acid, citric acid, glutaric acid, adipic acid, maleic acid, lactic acid, propionic acid, and hydroxyethane diphosphonic acid. and organic acids such as methanesulfonic acid; inorganic acids such as hydrochloric acid, phosphoric acid, sulfuric acid, zircohydrofluoric acid, hydrofluorosilicic acid, and nitric acid;

It is suitable that the resin emulsion (A) has a total amine value of 20 to 120 mgKOH/g, preferably 40 to 100 mgKOH/g.

In addition, the weight average molecular weight of the resin in the resin emulsion (A) is preferably in the range of 1,000 to 20,000, preferably 2,000 to 8,000, from the viewpoint of coating film properties such as room temperature drying property, corrosion resistance, and moisture resistance. ing.

In this specification, the average particle diameter is the value of the volume average particle diameter measured by the Coulter counter method at a measurement temperature of 20°C. Measurement by the Coulter counter method can be performed using, for example, "COULTERN4" (manufactured by Beckman Coulter, trade name).

Further, the amine value is measured according to JIS K 7237-1995. All values are amine values per resin nonvolatile content (mgKOH/g).

The weight average molecular weight is calculated by converting the retention time (retention capacity) measured using gel permeation chromatography (GPC) into the molecular weight of polystyrene using the retention time (retention capacity) of standard polystyrene with a known molecular weight measured under the same conditions. This is the value obtained by The columns are "TSKgelG-4000H×L", "TSKgel G-3000H×L", "TSKgel G-2500H×L", "TSKgelG-2000H×L" (all manufactured by Tosoh Corporation, product names). The experiment was carried out using four tubes under the following conditions: mobile phase: tetrahydrofuran, measurement temperature: 40°C, flow rate: 1 ml/min, detector: RI.

<Resin emulsion (B)>
In the present invention, the resin emulsion (B) is an aqueous dispersion obtained by dispersing in water a resin whose weight average molecular weight is lower than that of the resin emulsion (A).

As described above, it is preferable that the resin emulsion (B) has a functional group that can react with the functional group contained in the resin emulsion (A), and that it is preferably an epoxy group-containing resin emulsion.

When the resin emulsion (B) is an epoxy group-containing resin emulsion, examples of raw materials for its production include the epoxy group-containing compounds listed in the description of the epoxy resin (a1) above.

Among them, the resin emulsion (B) contains novolak type epoxy as a part of its components, from the viewpoint of obtaining a coating film with excellent curability and having many epoxy groups that can react with the amino groups contained in the resin emulsion (A). Preferably, the material contains a resin.

Furthermore, the epoxy equivalent of the resin emulsion (B) should be lower than that of the epoxy resin (a1) in the resin emulsion (A) from the viewpoint of compatibility between the first component (I) and the second component (II). In particular, it is suitable that the number is at least 50, preferably in the range of 100 to 500.

Further, the weight average molecular weight of the resin in the resin emulsion (B) is lower than that in the resin emulsion (A). It is considered that this further improves the compatibility between the first component (I) and the second component (II) of the composition of the present invention. The weight average molecular weight of the resin of the resin emulsion (B) is not particularly limited, and specifically, it is suitably within the range of 300 to 10,000, preferably 500 to 5,000.

The resin emulsion (B) is dispersed with a dispersion stabilizer or surfactant having an anionic, nonionic or cationic hydrophilic group, or the resin (B) itself has these hydrophilic groups. Due to their presence, the resin emulsion (B) can be well dispersed in the aqueous medium.

An example of the anionic hydrophilic group is an acidic group. Examples of the acidic group include carboxyl group, sulfonic acid group, phosphoric acid group, and phenolic hydroxyl group.

Examples of the nonionic hydrophilic group include a polyoxyalkylene group, a polyglycerin group, and the like.

Examples of the cationic hydrophilic group include primary to tertiary amino groups, ammonium groups, pyridinium groups, sulfonium groups, and phosphonium groups.

The average particle diameter of the resin emulsion (B) can be in the range of 50 to 1,500 nm, preferably 200 to 1,000 nm. When the average particle diameter is within this range, there is an effect that the film forming property of the composition after mixing the first component (I) and the second component (II) is excellent. Particularly in the present invention, from the viewpoint of film-forming properties of the aqueous coating composition, it is suitable that the average particle size of the resin emulsion (B) is larger than the average particle size of the aqueous dispersion of the resin emulsion (A).

A commercially available product can also be used as the resin emulsion (B). Specific examples include Watersol series (manufactured by DIC, trade name), Modepics series (manufactured by Arakawa Chemical Co., Ltd., trade name), Adeka Resin (manufactured by ADEKA, trade name), "Yuka Resin KE-278", "Yuka Resin KE-002'' and ``Yukaresin KE-307-2'' (manufactured by Yoshimura Yukagaku Co., Ltd., trade name).

<Softener (C)>
In addition, in the present invention, a softener (C) is included from the viewpoints of impact resistance of the formed coating film, film-forming properties in a low-temperature environment, and the like. As the softener (C), a compound having good mixing stability with the resin emulsion (B) is preferably used.

In this specification, a state in which the resin emulsion (B) and the softener (C) have good mixing stability means that they are mixed in equal amounts, stirred until visually homogeneous, and left at 20°C for 24 hours. Sometimes it means that the two are not separated.

As such a softener (C), an organic compound that is liquid at room temperature and has a weight average molecular weight equal to or lower than that of the resin of the resin emulsion (B) is suitable. Specific examples include glycol ether compounds, alkyl ester compounds, and epoxy compounds.

Glycol ether compounds include diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, dipropylene glycol monopropyl ether, Examples include propylene glycol monobutyl ether, tripropylene glycol monobutyl ether, and 2-ethylhexyl glycol.

Examples of alkyl ester compounds include dibutyl adipate, DBE (dibasic acid ester), dibutyl phthalate, di-2-ethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, diheptyl phthalate, di-n-octyl phthalate, butylbenzyl phthalate, and ethyl phthalate. Ethyl glycolate, di-2-ethylhexyl adipate, dibutyl diglycol adipate, 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate thyrate, 2,2,4-trimethyl-1,3-pentanediol 2-ethylhexanoate isobutyrate, 2,2,4-trimethyl-1,3-pentanediol di2-ethylhexanoate, etc. can be mentioned.

Epoxy compounds include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether , trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ether, glycerin polyglycidyl ether, diglycerin polyglycidyl ether, polyglycerin polyglycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether , cresyl glycidyl ether, tert-butylphenyl glycidyl ether, and other alkyl glycidyl ether compounds; butyric acid glycidyl ester, stearic acid glycidyl ester, neodecanoic acid glycidyl ester, epoxidized soybean oil, epoxybutyl stearate, epoxyhexahydrophthalic acid di2 - Alkylglycidyl ester compounds such as ethylhexyl, diisodecyl epoxyhexahydrophthalate, epoxytriglyceride, epoxidized octyl oleate, and epoxidized decyl oleate. The above compounds can be used alone or in combination of two or more.

Among the above, compounds having a functional group that can react with the functional groups contained in the resin emulsion (A), especially when the resin emulsion (A) is an amino group-containing resin emulsion, are used as softeners (C) such as epoxy compounds. It is suitable for use from the viewpoint of anti-corrosion properties.

<Rust-preventive pigment component (D)>
In the aqueous coating composition of the present invention, the first component (I) and/or the second component (II), preferably the first component (I), preferably further contains a rust preventive pigment component (D).

In the present invention, the rust preventive pigment component (D) is at least one selected from magnesium ions, aluminum ions, calcium ions, zinc ions, silicate ions, phosphate ions, vanadate ions, and molybdate ions in a corrosive environment. It is preferable that the anticorrosive pigment (d) contains an anticorrosive pigment (d) that can elute ions. Since the rust-preventing pigment component (D) contains the above-mentioned specific rust-preventing pigment (d), when the coating film applied on the rusted surface or metal base material is damaged, the above-mentioned ions are eluted and the defects are removed. Corrosion prevention can be more effectively exerted by acting on .

In the present invention, the presence or absence of ion elution of the rust preventive pigment (d) can be investigated by, for example, eluating the rust preventive pigment (d) into an aqueous sodium chloride solution and measuring the elution amount by ICP emission spectrometry. . More specifically, a supernatant liquid obtained by adding 10% by mass of anticorrosive pigment (d) to a sodium chloride aqueous solution with a concentration of 5% by mass, stirring at 25°C for 6 hours, and removing the precipitate after standing for 24 hours. There is a method of detecting the presence or absence of the amount of dissolved elements measured by ICP emission spectrometry.

In the present invention, depending on the form in which the first component (I) contains the rust preventive pigment component (D) together with the resin emulsion (A), even if the first component (I) contains the rust preventive pigment component (D) in a sufficient amount, the first component ( The production and storage stability of I) is good, and the coating film formed from the aqueous coating composition of the present invention can exhibit stable anticorrosion properties.

Specific examples of the rust-preventing pigment (d) that can be included in the rust-preventing pigment component (D) include single compounds, composite compounds, and compositions containing multiple of these compounds, as long as they are components that can elute the ions. There is no restriction on the form, and specific examples include zinc phosphate, magnesium phosphate, magnesium phosphate/ammonium eutectoid, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate/calcium eutectoid, phosphorus. Magnesium acid/cobalt eutectoid, magnesium phosphate/nickel eutectoid, calcium phosphate, calcium ammonium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium fluoride phosphate, aluminum phosphate, aluminum hydrogen phosphate, etc. Phosphate-based metal compounds;
Phosphite-based metal compounds such as magnesium phosphite, calcium phosphite, magnesium/calcium phosphite eutectoid, basic zinc phosphite, barium phosphite, manganese phosphite, calcium hypophosphite;
Calcium silicate, zinc silicate, aluminum silicate, aluminum orthosilicate, hydrated aluminum silicate, aluminosilicate, borosilicate, berylosilicate, calcium aluminum silicate, sodium aluminum silicate, beryllium aluminum silicate, silicate Silicate metal salts such as sodium acid, calcium orthosilicate, calcium metasilicate, sodium calcium silicate, zirconium silicate, magnesium orthosilicate, magnesium metasilicate, calcium magnesium silicate, manganese silicate, barium silicate; magnesium ion exchange Metal ion exchange silica compounds such as silica, calcium ion exchange silica, vanadium ion exchange silica;
Condensed phosphate metal compounds such as aluminum dihydrogen tripolyphosphate, magnesium tripolyphosphate, aluminum tripolyphosphate, zinc dihydrogen tripolyphosphate;
Vanadium-based metal compounds such as vanadium pentoxide, calcium vanadate, magnesium vanadate and ammonium metavanadate, fired products of manganese oxide and vanadium oxide, fired products of calcium phosphate and vanadium oxide;
Molybdate metal compounds such as aluminum molybdate, calcium molybdate, aluminum phosphomolybdate;
Zinc-based compounds such as zinc and zinc oxide;
Silica-based compounds such as silica and colloidal silica;
Complex metal oxides such as complex oxides of iron oxide and magnesium oxide, complex oxides of iron oxide and calcium oxide, complex oxides of iron oxide and zinc oxide;
etc. can be mentioned. As described above, these may be used alone or in combination of two or more, or may be a composite of two or more. Further, products modified or treated with silica, silicate compounds such as calcium silicate, magnesium oxide, etc., of these exemplified compounds are also included in the antirust pigment (d).

In particular, in the present invention, the rust preventive pigment (d) is a component capable of eluting silicate ions and/or phosphate ions, and at least one metal ion selected from magnesium ions, aluminum ions, calcium ions, and zinc ions. This is suitable because it has excellent spot rust suppression properties and anticorrosion properties against rusted surfaces and exposed metal surfaces. That is, in the present invention, the rust-preventive pigment (d) is a component that can elute [1] silicate ions, and elutes at least one metal ion selected from magnesium ions, aluminum ions, calcium ions, and zinc ions. [2] A component that can elute phosphate ions and at least one metal ion selected from magnesium ions, aluminum ions, calcium ions, and zinc ions, or [3] A component that can elute silicate ions and phosphate ions, and a component that can elute at least one metal ion selected from magnesium ions, aluminum ions, calcium ions, and zinc ions. Are suitable.

Particularly suitable is an embodiment in which the rust-preventive pigment (d) is a component capable of eluting at least one metal ion selected from silicate ions, phosphate ions, and magnesium ions, aluminum ions, calcium ions, and zinc ions. There is. In other words, it is particularly preferable that the component is capable of eluting silicate ions and phosphate ions, and is also capable of eluting at least one metal ion selected from magnesium ions, aluminum ions, calcium ions, and zinc ions. Are suitable.

The rust preventive pigment (d) is not limited in its form as long as it can elute silicate ions and/or phosphate ions together with the above metal ions, and may be a single compound or a composite compound. Alternatively, the composition may be a combination of a plurality of the above compounds. For example, the combination of a magnesium oxide treated product of aluminum dihydrogen tripolyphosphate and magnesium ion-exchanged silica can be combined with silicate ions, phosphate ions, and at least one metal selected from magnesium ions, aluminum ions, calcium ions, and zinc ions. This is an example of a rust preventive pigment (d) that can elute ions.

Among the rust preventive pigments (d), the rust preventive pigment that can elute silicate ions may contain a silicate compound that can elute silicate ions in a corrosive environment. For example, silica, colloidal silica, compounds listed in the explanation of the rust preventive pigment (d) above may be modified with silicate compounds, metal ion exchange silica compounds such as magnesium ion exchange silica, calcium ion exchange silica, etc. can. These can be used alone or in combination of two or more.

The anticorrosive pigment that can elute phosphate ions only needs to contain a phosphoric acid compound that can elute phosphate ions in a corrosive environment. For example, magnesium phosphate, magnesium phosphate/ammonium eutectoid, magnesium monohydrogen phosphate, magnesium dihydrogen phosphate, magnesium phosphate/calcium phosphate eutectoid, magnesium phosphate/cobalt eutectoid, magnesium nickel phosphate. Examples include eutectoid, magnesium phosphite, magnesium/calcium phosphite eutectoid, magnesium tripolyphosphate, magnesium oxide treated aluminum dihydrogen tripolyphosphate, magnesium oxide treated zinc dihydrogen tripolyphosphate, vanadium phosphorus, etc. be able to. These can be used alone or in combination of two or more.

The anti-corrosion pigment that can elute magnesium ions only needs to contain a magnesium compound that can elute magnesium ions in a corrosive environment. Specifically, for example, a compound obtained by treating the compounds listed in the explanation of the rust preventive pigment (d) with magnesium oxide, magnesium phosphate, magnesium phosphate/ammonium eutectoid, magnesium monohydrogen phosphate, dihydrogen phosphate, etc. Magnesium hydrogen, magnesium phosphate and calcium eutectoid, magnesium phosphate and cobalt eutectoid, magnesium phosphate and nickel eutectoid, magnesium phosphite, magnesium phosphite and calcium eutectoid, magnesium ion exchange silica, Examples include magnesium tripolyphosphate, magnesium vanadate, magnesium metasilicate, magnesium calcium silicate, iron oxide and magnesium oxide composite oxide, and magnesium vanadate. These can be used alone or in combination of two or more.

The anticorrosive pigment that can elute aluminum ions only needs to contain an aluminum compound that can elute aluminum ions in a corrosive environment. For example, aluminum phosphate, aluminum hydrogen phosphate, aluminum dihydrogen tripolyphosphate, aluminum tripolyphosphate, aluminum molybdate, aluminum silicate, aluminum orthosilicate, hydrated aluminum silicate, aluminosilicate, calcium aluminum silicate, silicic acid Examples include sodium aluminum, beryllium aluminum silicate, aluminum phosphomolybdate, and aluminum vanadate. These can be used alone or in combination of two or more.

The anticorrosive pigment capable of eluting calcium ions only needs to contain a calcium compound capable of eluting calcium ions in a corrosive environment. For example, magnesium/calcium phosphate eutectoid, calcium phosphate, calcium ammonium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium fluoride phosphate, calcium phosphite, magnesium/calcium phosphite eutectoid, hypochlorite. Calcium phosphate, calcium ion exchange silica, calcium vanadate, calcined product of calcium phosphate and vanadium oxide, calcium molybdate, composite oxide of iron oxide and calcium oxide, calcium silicate, calcium aluminum silicate, calcium orthosilicate, calcium metasilicate, Examples include calcium sodium silicate, magnesium calcium silicate, and the like. These can be used alone or in combination of two or more.

The anticorrosive pigment that can elute zinc ions only needs to contain a zinc compound that can elute zinc ions in a corrosive environment. Examples include zinc, zinc oxide, zinc phosphate, basic zinc phosphite, zinc dihydrogen tripolyphosphate, zinc silicate, and composite metal oxides such as composite oxides of iron oxide and zinc oxide. . These can be used alone or in combination of two or more.

The rust-preventive pigment component (D) used in the present invention can contain other rust-preventive pigments other than the rust-preventive pigment (d), if necessary. Specific examples of such other antirust pigments include cobalt compounds such as cobalt hydroxide; boric acid compounds such as barium metaborate; iron phosphide, manganese phosphide, nickel phosphide, cobalt phosphide, and copper phosphide. Examples include phosphides such as.

When using other rust preventive pigments, the amount used in that case can be 30% by mass or less in the rust preventive pigment component (D).

As the antirust pigment component (D), commercially available products can be used alone or in combination. Such commercial products include, for example, "EXPERT NP-1000", "EXPERT NP-1020C", "EXPERT NP-1100", "EXPERT NP-1102" (trade names, manufactured by Toho Pigment Industries Co., Ltd.), and "LF Bousei CP-". Z”, “LF Vosei MZP-500”, “LF Vosei CRFC-1”, “LF Vosei M-PSN”, “LF Vosei MC-400WR”, “LF Vosei PM-300”, “LF Vosei PM-308” (The above are manufactured by Kikuchi Color Co., Ltd., product names), "K-WHITE140", "K-WHITE Ca650", "K-WHITE450H", "K-WHITEG-105", "K-WHITE #105", "K-WHITE" #82” (manufactured by Teika, product name), “SHIELDEX C303”, “SHIELDEX AC-3”, “SHIELDEXC-5” (all manufactured by W.R. Grace & Co.), “Silo Mask 52” ", "Silo Mask 52M," "Silo Mask 22MR-H," "Silo Mask Mg" (manufactured by Fuji Silicia), and "Novinox ACE-110" (manufactured by SNCZ, France).

The amount of the rust preventive pigment component (D) is 1 to 100 parts by weight, preferably 5 to 90 parts by weight, based on 100 parts by weight of the nonvolatile content of the resin contained in the aqueous coating composition, especially the resin emulsion (A). It is suitable that the amount is in the range of 10 to 80 parts by weight, more preferably 10 to 80 parts by weight.

<Fibrous inorganic compound (E)>
In the aqueous coating composition of the present invention, the first component (I) and/or the second component (II), preferably the first component (I), preferably further contains a fibrous inorganic compound (E).

Although the reason is not clear, the fibrous inorganic compound (E) is effective in improving adhesion to rusted surfaces and corrosion resistance.

The above-mentioned fibrous inorganic compound (E) is not particularly limited in its material, manufacturing method, production area, etc., and its specific examples include glass fiber, silicon carbide, silicon nitride, wollastonite, sepiolite, chrysotile, amosite, and tremolite. , zeolite, calcium metasilicate, zonolite, potassium titanate, rock wool, aluminum silicate, carbon fiber, aramid fiber, aluminum borate, acicular calcium carbonate, acicular basic magnesium sulfate, glass flakes, acicular zinc oxide, aragonite Examples include type light calcium carbonate, spindle type light calcium carbonate, and sachin white. These can be used alone or in combination of two or more.

In the present invention, it is preferable to use the fibrous inorganic compound (E) having an aspect ratio of 3.5 or more, preferably within the range of 4 to 25.

The aspect ratio is the value of the major axis diameter/minor axis diameter of an inorganic acicular pigment, and the minor axis diameter and major axis diameter here refer to each of the 100 primary particles present within a certain area as determined by electron microscopy. The short axis diameter and long axis diameter were measured, and the number average value of each was determined.

Further, the average fiber length of the fibrous inorganic compound (E) is preferably in the range of 5 to 300 μm, particularly 10 to 200 μm. In this specification, the average fiber length is the average value of the major axis diameters obtained in the measurement of aspect ratio.

In the present invention, the blending amount of the fibrous inorganic compound (E) is 0.1 to 30 parts by mass, preferably 0.1 to 30 parts by mass based on 100 parts by mass of the total nonvolatile content of the resin contained in the paint, especially the resin emulsion (A). Suitably, the amount is in the range of 5 to 25 parts by weight.

<Polycarbodiimide compound (F)>
Further, it is preferable that the first component (I) and/or the second component (II), preferably the second component (II), further contain a polycarbodiimide compound (F).

Inclusion of the polycarbodiimide compound (F) in the aqueous coating composition is effective in improving the moisture resistance of the formed coating film.

Such a polycarbodiimide compound (F) is a polymer having a -N=C=N- group in its molecule, and can be produced, for example, by a decarboxylation condensation reaction of diisocyanate in the presence of a carbodiimidation catalyst. Examples of the carbodiimidation catalyst include tin, magnesium oxide, potassium ion, 18-crown-6, 3-methyl-1-phenyl-2-phosphorene oxide, and combinations thereof. These can be used alone or in combination of two or more.

Examples of diisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, isophorone diisocyanate, methylcyclohexyl diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1, 3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, norbornene diisocyanate, 2,4,6-triisopropylphenyl diisocyanate, 1,12-diisocyanate Decarbonization condensation of one or more polyfunctional isocyanates such as dodecane, 2,4,-bis-(8-octyl isocyanate)-1,3-dioctylcyclobutane, and n-pentane-1,4-diisocyanate. By reacting, it is converted into carbodiimide, and the residual isocyanate group at the end is capped with a hydrophilic group in order to impart water dilubility.

Examples of the hydrophilic group to be capped include alkyl sulfonate residues, quaternary salts of dialkylamino alcohol residues, and polyoxyalkylene residues whose alkoxy group ends are capped.

Examples of the polycarbodiimide compound (F) include "Carbodilyte V-02", "Carbodilyte V-04", "Carbodilyte V-02-L2", "Carbodilyte E-02", "Carbodilyte E-03A", and "ElastostabH01". ” (all product names, manufactured by Nisshinbo Chemical Co., Ltd.) can be used.

The blending amount of the polycarbodiimide compound (F) is 0.1 to 10 parts by mass, preferably 0.5 parts by mass, based on 100 parts by mass of the nonvolatile content of the resin contained in the aqueous coating composition, especially the resin emulsion (A). A content in the range of 5 parts by mass is suitable from the viewpoint of water absorption and anticorrosion properties of the coating film. When the second component (II) contains a polycarbodiimide compound (F), the proportion of the polycarbodiimide compound (F) to the entire second component (II) is 1 to 20% by mass, particularly 3 to 15% by mass. % range is appropriate.

In the aqueous coating composition of the present invention, colored pigments, extender pigments, pigment dispersants, organic solvents, surface conditioners, antifoaming agents, thickeners, curing catalysts, surfactants, antisettling agents, plasticizers, reactive Conventional paint additives such as anti-freeze diluents, antifreeze agents, antiskinning agents, pH adjusters, preservatives, etc. can be incorporated into the first component (I) and/or the second component (II).

Among these, examples of color pigments include titanium oxide, carbon black, yellow lead, ocher, yellow iron oxide, Hansa yellow, pigment yellow, chrome orange, chrome vermilion, permanent orange, amber, permanent red, brilliant carmine, and fast violet. , methyl violet lake, ultramarine, navy blue, cobalt blue, phthalocyanine blue, pigment green, naphthol green, aluminum paste, etc. These can be used alone or in combination of two or more.

The amount of the coloring pigment to be blended is within the range of 5 to 90 parts by weight, preferably 10 to 50 parts by weight, based on 100 parts by weight of the nonvolatile content of the resin, especially the resin emulsion (A), contained in the aqueous coating composition. That is suitable.

Examples of extender pigments include talc, silica, calcium carbonate, mica, kaolin, barium sulfate, and zinc white (zinc oxide). These can be used alone or in combination of two or more.

From the viewpoint of water resistance, the amount of the extender pigment to be blended is 10 to 100 parts by mass, preferably 20 to 70 parts by mass, based on 100 parts by mass of the nonvolatile resin contained in the water-based coating composition. ing.

The pigment dispersant used to disperse the pigment is not particularly limited, but an acidic dispersant having an acid value of 50 mgKOH/g or less is suitable. Examples of such pigment dispersants include acrylic resins, styrene acrylic resins, maleic acid resins, styrene maleic acid resins, α-olefin maleic acid resins, urethane resins, ester resins, sulfonic acid resins, phosphoric acid resins, etc. These may be those into which polyalkylene glycol groups, such as polyethylene glycol and polypropylene glycol, have been introduced from the viewpoint of dispersion stability.

The blending amount of the pigment dispersant is based on 100 parts by mass of non-volatile matter of the resin emulsion (A), from the viewpoint of suppressing thickening during production of the component containing the rust-preventing pigment component (D) and storage stability. A range of 1 to 20 parts by weight, particularly 3 to 15 parts by weight is preferred.

The aqueous coating composition of the present invention comprises a resin emulsion (A) as a first component (I) and other components contained as necessary, a resin emulsion (B) as a second component (II), and a softener (C). ) and other components included as necessary are dissolved or dispersed in the aqueous medium. The aqueous medium has water as its main component, and may be water or a mixture of water and an organic solvent.

<Organic solvent>
In the present invention, conventionally known organic solvents can be used without limitation, but specific examples thereof include alcohol compounds such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; dioxane, tetrahydrofuran, etc. Ether compounds of; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol mono-tert-butyl ether, diethylene glycol Glycol ether compounds such as monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether;
Dipropylene glycol ether compounds such as dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol monoisopropyl ether;
Ester compounds such as ethyl acetate, butyl acetate, isobutyl acetate, 3-methoxybutyl acetate;
Examples include ketone compounds such as methyl isopropyl ketone, diisobutyl ketone, methyl isobutyl ketone, diethyl ketone, ethyl butyl ketone, ethylpropyl ketone, dipropyl ketone, methyl ethyl ketone, etc., and these can be used alone or in combination of two or more types. can. The organic solvent has a boiling point of less than 200°C, particularly 80 to 190°C, from the viewpoint of long-term corrosion protection and low-temperature film forming properties, and more preferably dissolves at least 10g, preferably 20g, in 100g of water at 20°C. Preference is given to using organic solvents.

The content of the organic solvent is within the range of 0.1 to 30 parts by mass, preferably 3 to 25 parts by mass, based on 100 parts by mass of the nonvolatile content of the resin contained in the aqueous coating composition, especially the resin emulsion (A). can be found in

<Water-based paint composition>
During storage, the aqueous coating composition of the present invention is stored in a two-component form consisting of a first component (I) and a second component (II). This is because the functional groups contained in the first component (I) and the functional groups contained in the second component (II) easily react at room temperature. At the time of use, the aqueous coating composition used for painting can be prepared by mixing the first component (I) and the second component (II) by a known method.

The aqueous coating composition of the present invention is a two-component coating composition in which a component containing a resin emulsion (A) is a first component (I), and a component containing a resin emulsion (B) is a second component (II). It is.

The present invention is characterized in that the second component (II) contains a softener (C).

In the present invention, since the softener (C) is present on the second component (II) side together with the resin emulsion (B), the anticorrosion properties of the coating film are further improved. The reason for this is not clear, but because the resin particles of the resin emulsion (B) and the softener (C) have good mixing stability, by mixing them in advance, the resin emulsion (A ) and the reactive functional groups possessed by the resin emulsion (B).

In the present invention, the proportion of the softener (C) in the entire second component (II) is 1 to 30% by mass, particularly preferably 5 to 20% by mass.

In the present invention, the appropriate pH range for the first component (I) is 5.0 to 9.0, particularly 7.0 to 8.5, and the appropriate pH range for the second component (II) is It is preferably within the range of 5.0 to 9.0, particularly 6.0 to 8.5.

When the pH is within this range, it is possible to prepare a coating composition in which both component (I) and component (II) have excellent production and storage stability and are excellent in mutual miscibility.

In this specification, pH is measured using a pH meter after adjusting the temperature of a sample in a sealed can state to 20°C.

The blending ratio of the first component (I) and the second component (II) is 0.3 to 1 equivalent of the functional group contained in the second component to 1 equivalent of the functional group contained in the first component (I). .5 equivalents, preferably within the range of 0.5 to 1.2 equivalents.

Furthermore, when painting, it can be used after being diluted with deionized water if necessary. For example, in the case of spray painting, the viscosity at that time is determined by Ford cup viscometer No. 4 (at 20° C.), it is preferable to adjust the time to 20 to 60 seconds, and more preferably to adjust it to 30 to 50 seconds. In this case, the solid content is preferably about 35 to 65% by mass, more preferably about 40 to 60% by mass.

There is no particular restriction on the object to be coated to which the method of the present invention is applied. Usually steel is used, but it can also be applied to non-ferrous metals. Specifically, it can be applied to architectural structures such as houses and buildings; civil engineering structures such as towers, bridges, and tanks; and various large-scale plants such as electric power, oil, and gas facilities. Structures; outdoor equipment such as guard fences; industrial equipment such as railway vehicles and construction machinery; and painted objects that have been coated with primer or intermediate coats and top coats as necessary. It will be done.

In particular, the effect can be exhibited not only on newly installed objects but also on existing objects made of rusted base materials.

When applying the anticorrosive coating using the aqueous coating composition of the present invention to the surface of the base material where rust has occurred, the rust that has formed on the surface may be removed in advance.

There are no restrictions on the method for removing rust, and examples include hand tools such as blasting, scrapers, and wire brushes, and electric tools such as disk sanders, wire cups, and electric chisels. These can be carried out singly or in combination of two or more, and if necessary, washing with water may be carried out.

When removing rust using the method of the present invention, it is not necessary to completely remove rust and old paint from the surface of the substrate to be anti-corrosion coated, leaving metal exposed on the entire surface; The remaining rust portion and the active film (old paint film that does not peel off easily) may be mixed together in the part.

The degree of rust generation after surface treatment is not particularly limited; for example, the effect of the present invention can be exerted even if the rust generation area ratio is 3% or more, particularly 10% or more. Can be done.

The rust occurrence area ratio is the percentage of the area of the rust occurrence site to the area of the object to be coated. Photographs after surface treatment are taken at five random locations, the area of the rust occurrence site in each photograph is calculated, and the average is calculated. It can be obtained by

In the anticorrosive coating method of the present invention, the dry theoretical thickness of the anticorrosive coating formed from the aqueous coating composition can be in the range of 10 to 200 μm, preferably 30 to 150 μm.

In the present invention, the dry theoretical film thickness is calculated by the following formula.
A=(B×NV)/(C×100)
A: Theoretical dry film thickness (μm)
B: Application amount (g/m ² )
NV: Paint non-volatile content concentration (%)
C: Specific gravity of paint (g/cm ³ )
The specific gravity of the paint to determine the dry theoretical film thickness shall be measured according to the K 7232-1986 4.2 specific gravity cup method.

Conventionally known methods such as air spraying, airless spraying, brushing, and roller coating can be applied to the aqueous coating composition. As for the drying method, it is desirable to dry at room temperature for 1 to 48 hours, preferably for 2 to 16 hours, and it is also possible to perform forced drying or heat drying if necessary.

In the anticorrosive coating method of the present invention, a top coat different from the aqueous coating composition can be applied in a single layer or in multiple layers on the anticorrosive coating film formed using the aqueous coating composition.

The present invention will be further explained below with reference to Examples. Here, "parts" and "%" mean "parts by mass" and "% by mass", respectively.

<Production of resin emulsion (A)>
Manufacturing example 1
In a flask equipped with a stirrer, a thermometer, a nitrogen inlet tube, and a reflux condenser, add 3200 parts of bisphenol A resin (epoxy equivalent: 190, number average molecular weight: 375), manufactured by Mitsubishi Chemical Corporation (trade name: "jER828"), bisphenol A (molecular weight: 228), 900 parts of methyl isobutyl ketone (boiling point: 120°C), and 5.0 parts of benzyldimethylamine were charged, and the mixture was reacted at 120°C until the epoxy equivalent per nonvolatile content became 2,500 g/equivalent.

Next, 590 parts of a ketimine compound of 3,3'-diaminodipropylamine using methyl isobutyl ketone was added, and the mixture was reacted at 120°C for 1 hour. Thereafter, 54 parts of deionized water and 380 parts of neodecanoic acid glycidyl ester were charged, and the mixture was reacted at 100°C for 2 hours. After that, 90 parts of acetic acid and 70 parts of deionized water were added, and the internal solution was stirred and mixed. After adding 6500 parts of deionized water and dispersing in water, the methyl isobutyl ketone was removed under reduced pressure, and solidified with deionized water. The emulsion was adjusted to obtain an amino group-containing resin emulsion (A-1) having a primary amino group at the resin end and having a milky white color and a nonvolatile content of 45%.

In emulsion (A-1), the weight average molecular weight of the resin before neutralization was 7000, the average particle diameter was 250 nm, and the amine value per nonvolatile content was 60 mgKOH/g.

Production examples 2 to 5
Resin emulsions (A-2) to (A-5) were produced in the same manner except that the compositions were as shown in Table 1 below.

<Manufacture of water-based paint composition>
Example 1
In a container, 222 parts of amino group-containing resin emulsion (A-1) (100 parts of non-volatile content), 10 parts of rust preventive pigment (D-1), 10 parts of rust preventive pigment (D-2), and rust preventive pigment (D- 7) 20 parts, 10 parts of fibrous inorganic compound, 8 parts of pigment dispersant, 20 parts of ethylene glycol monobutyl ether (boiling point 171.2°C), 40 parts of titanium oxide, and 60 parts of talc were mixed and stirred to form the main agent. Got the ingredients. In a separate container, 35.2 parts of epoxy resin emulsion (B-1) (17.6 parts of nonvolatile content), 5 parts of propylene glycol diglycidyl ether, and 7.5 parts of polycarbodiimide emulsion (3 parts of nonvolatile content) were added. The mixture was stirred and mixed to obtain a curing agent component, and the mixture was mixed with the base component to obtain an aqueous coating composition (I-1).

Examples 2 to 31 and Comparative Examples 1 to 3
Water-based coating compositions (I-2) to (I-34) were obtained in the same manner as in Example 1, except that the compositions were as shown in Table 2 below. Evaluation tests were conducted on each of the obtained paints according to the following methods and criteria. The results are also shown in Table 2.
The blending amounts of resin emulsion (A), resin emulsion (B), and polycarbodiimide emulsion (F) in Table 2 are expressed as non-volatile content.

<Creation of a test plate painted on the surface with residual rust>
Shot-blasted mild steel plates measuring 70 mm wide x 150 mm long x 3 mm thick were subjected to an open exposure test on the Pacific coast of Chikura-cho, Chiba Prefecture (30 m off-shore distance) for 4 months at an angle of 30 degrees facing south. A rusted steel plate with a rusted area of 100% was prepared, and the surface of the rusted steel plate was scraped with a wire cup to obtain a simple surface adjustment plate. The rusted area of the simple substrate adjustment board was 85%.

Next, each water-based paint composition (I-1) to (I-34) was air-sprayed onto the entire surface of the substrate conditioning board so that the theoretical dry film thickness was 100 μm, and dried at 23° C. for 24 hours. Ta. Next, a weakly solvent-soluble epoxy resin intermediate coating paint "Ceratect Mild Intercoat (E)" (trade name, manufactured by Kansai Paint Co., Ltd., base agent/curing agent mass ratio 17/1) was applied to a dry film thickness of 30 μm. was spray coated and dried at 23°C for 24 hours. Next, a low-contamination, weakly solvent-soluble isocyanate-cured polyurethane resin topcoat paint "Ceratect U Mild Topcoat" (trade name, manufactured by Kansai Paint Co., Ltd., base agent/curing agent mass ratio 6/1) was applied to a dry film thickness of 25 μm. The sample was spray-painted and cured for 7 days in a constant temperature room at 23° C. and 50% humidity to obtain a test coated plate coated on the surface with residual rust.

<Creation of test plate painted on mild steel plate>
A mild steel plate of 70 mm width x 150 mm length x 3 mm thickness was shot-blasted and no rust remained on the base material surface, and each water-based paint composition (I-1) to (I -34) was air-sprayed to a theoretical dry film thickness of 100 μm and cured for 7 days in a constant temperature room at 23°C and 50% humidity to obtain a test coated plate coated on a mild steel plate surface.

(*) Rust preventive pigment (D-1): "K-WHITE G-105" manufactured by Teika, trade name, magnesium oxide treated aluminum dihydrogen tripolyphosphate, magnesium oxide treated amount 15%, (*) Rust preventive Pigment (D-2): "LF Bousei MZP-500", trade name, manufactured by Kikuchi Color Co., Ltd., magnesium phosphate,
(*) Antirust pigment (D-3): "EXPERT NP-1000" manufactured by Toho Pigment Industries Co., Ltd., trade name, calcium phosphate,
(*) Rust preventive pigment (D-4): Zinc phosphate tetrahydrate, manufactured by Yoneyama Pharmaceutical Co., Ltd., reagent, zinc phosphate,
(*) Antirust pigment (D-5): "SHIELDEX C303" W. R. Grace & Co. company, product name, calcium ion exchange silica,
(*) Rust preventive pigment (D-6): "Silo Mask Mg" manufactured by Fuji Silysia Chemical Co., Ltd., trade name, magnesium ion exchange silica,
(*) Rust preventive pigment (D-7): "Silo Mask 22MR-H" manufactured by Fuji Silysia Chemical Co., Ltd., trade name, magnesium ion exchange silica,
(*) Fibrous inorganic compound: glass fiber, aspect ratio 20, average fiber length 80 μm,
(*) Pigment dispersant: polyethylene glycol-polypropylene glycol modified styrene maleic acid copolymer, acid value 10 mgKOH/g,
(*) Alkyl glycidyl ether: "Recaresin L200" trade name, manufactured by Shin Nihon Rikagaku Co., Ltd., glycidyl ether having an alkyl group having 12 and/or 14 carbon atoms,
(*) Epoxy resin emulsion (B-1): Nonionic phenol novolak type epoxy resin emulsion, non-volatile content 50%, epoxy equivalent per non-volatile content 200, weight average molecular weight 1200, average particle diameter 550 nm,
(*) Epoxy resin emulsion (B-2): Nonionic cresol novolak type epoxy resin emulsion, non-volatile content 45%, epoxy equivalent per non-volatile content 475, weight average molecular weight 1500, average particle diameter 500 nm,
(*) Epoxy resin emulsion (B-3): Nonionic bisphenol A type epoxy resin emulsion, non-volatile content 50%, epoxy equivalent per non-volatile content 200, weight average molecular weight 1200, average particle diameter 550 nm,
(*) Polypropylene glycol diglycidyl ether: epoxy equivalent 300,
(*) Dibasic acid ester: “No23 ester (DBE)” product name manufactured by Sankyo Chemical Co., Ltd.
(*) Polycarbodiimide emulsion: nonvolatile content 40%, carbodiimide equivalent weight 365.

<Evaluation test>
(*)Storage Stability The second component of each water-based paint obtained in the Examples and Comparative Examples was sealed and stored in a constant temperature room at 40°C, and the condition after storage for 60 days was evaluated according to the following criteria.
S: No change,
A: Very slight aggregation is observed, but when the sample is stirred by hand, it immediately returns to the state before storage, and there is no problem.
B: Aggregation is observed, and the sample does not return to its pre-storage state even if it is manually stirred.
C: Significant agglomerated lumps are observed.

(*) Film-forming property at 5°C: Apply each water-based paint composition to a glass plate using an applicator to a dry film thickness of 60 μm, and dry it at 5°C for 24 hours. The condition of the coated surface is based on the following criteria. evaluated.
S: Very good film-forming properties, with no cracks observed at all.
A: Good film-forming properties, with very slight cracks observed only at the edges of the film.
B: Although it has film-forming properties and adheres to the glass plate, cracks are observed throughout.
C: No film was formed, cracks occurred throughout the coating, and peeling was observed in the coating.

(*) Moisture resistance A test plate coated on a mild steel plate surface was left for 120 hours under conditions of 50° C. and 98 RH% with pure water, and then evaluated according to the following criteria.
S: The painted surface is in very good condition, with no blisters observed.
A: The painted surface is in good condition, with very few blisters of 1 mm or less observed.
B: The condition of the painted surface is somewhat poor, with blisters exceeding 1 mm observed.
C: The condition of the painted surface is poor, and blisters are observed on the entire painted surface.

(*) Corrosion resistance A combined cycle corrosion test using a 5% sodium chloride aqueous solution specified in JIS K 5621 was performed on each test coated plate with each water-based paint composition coated on the rust-remaining surface and the mild steel plate surface. This was carried out for 1200 hours, and the surface of the general part and cut part of the test coated plate was observed and evaluated according to the following criteria.
(General section)
S: No rust formation observed.
A: Rust with a diameter of less than 5 mm is observed at 1 to 5 points on the test specimen.
B: 1 to 5 rust spots are observed on the test specimen and the size exceeds 5 mm, or 6 to 15 rust spots are observed regardless of the size of the rust.
C: Rust formation is observed on the test piece at 15 or more points.
(cut part)
S: Rust progresses from the cut part, the maximum width of blisters is 10 mm or less across the cut,
A: The maximum value of rust and blistering that progresses from the cut is more than 10 mm and less than 20 mm across the cut,
B: The maximum value of rust and blistering that progresses from the cut is more than 20 mm and less than 30 mm across the cut,
C: The maximum value of rust and blistering that progresses from the cut portion exceeds 30 mm across the cut.

Claims (11)

A two-component type comprising a first component (I) containing a resin emulsion (A) and a rust preventive pigment component (D), and a second component (II) containing a resin emulsion (B) and a softener (C). A water-based paint composition, comprising:
The resin emulsion (A) is an amino group-containing resin emulsion having a primary amino group,
The resin emulsion (B) is an epoxy group-containing resin emulsion,
The weight average molecular weight of the resin in the resin emulsion (B) is lower than the weight average molecular weight of the resin in the resin emulsion (A), and the softener (C) is contained in the second component (II) in an amount of 1 to 30% by mass. Included within the range,
The softener (C) contained in the second component (II) has a functional group that can react with the resin of the resin emulsion (A),
The softener (C) is an organic compound containing a glycol ether compound, an alkyl ester compound, or an epoxy compound and having a weight average molecular weight equal to or lower than that of the resin of the resin emulsion (B),
The glycol ether compounds include diethylene glycol monobutyl ether, diethylene glycol dibutyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, propylene glycol monobutyl ether, propylene glycol monophenyl ether, dipropylene glycol monopropyl ether, Containing one or more selected from the group consisting of propylene glycol monobutyl ether, tripropylene glycol monobutyl ether, and 2-ethylhexyl glycol,
The epoxy compounds include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and 1,6-hexanediol diglycidyl ether. , glycidyl ether having an alkyl group having 12 and/or 14 carbon atoms, trimethylolpropane polyglycidyl ether, hexahydrophthalic acid diglycidyl ester, glycerin polyglycidyl ether, diglycerin polyglycidyl ether, polyglycerin polyglycidyl ether, butylglycidyl Ether, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, benzyl glycidyl ether, cresyl glycidyl ether, tert-butylphenyl glycidyl ether, butyric acid glycidyl ester, stearic acid glycidyl ester, neodecanoic acid glycidyl ester, epoxidized soybean oil, epoxy butyl stear ester, di-2-ethylhexyl epoxyhexahydrophthalate, diisodecyl epoxyhexahydrophthalate, epoxytriglyceride, epoxidized octyl oleate, and epoxidized decyl oleate. Two-component water-based paint composition. The aqueous coating composition according to claim 1, wherein the resin emulsion (B) is an emulsion of a novolac type epoxy resin. The resin emulsion (A) contained in the first component (I) is a modified resin emulsion using a reactive group-containing softener (a4) as a raw material,
The aqueous coating composition according to claim 1 or 2 , wherein the reactive group-containing softener (a4) is a compound having a functional group such as a carboxyl group and/or a glycidyl group. The antirust pigment component (D) contains at least one ion selected from magnesium ions, aluminum ions, calcium ions, zinc ions, silicate ions, phosphate ions, vanadate ions, and molybdate ions as part of its components. The aqueous coating composition according to any one of claims 1 to 3 , comprising a rust preventive pigment (d) that can elute. The aqueous coating composition according to any one of claims 1 to 4 , wherein the first component (I) and/or the second component (II) further contains a fibrous inorganic compound (E). The aqueous coating composition according to any one of claims 1 to 5 , wherein the first component and/or the second component (II) further contains a polycarbodiimide compound (F). The aqueous coating composition according to any one of claims 1 to 6 , wherein the first component and the second component both have a pH of 5.0 to 9.0. An aqueous coating composition obtained by mixing the first component (I) and the second component (II) according to any one of claims 1 to 7 . An anticorrosive coating method comprising coating an object to be coated with the aqueous coating composition according to claim 8 . The anticorrosive coating method according to claim 9 , wherein the object to be coated is a base material surface on which rust remains. A coated article coated with the anticorrosive coating according to claim 10 .