JP2022003141A - Low-voc anticorrosive coating composition, anticorrosive coating film, base with coating film, and production method for base with coating film - Google Patents

Abstract

To provide a coating composition that can form a coating film having excellent oil resistance, solvent resistance, chemical resistance and anticorrosiveness, and provide a coating composition that can form a coating film that has, besides these performances, well-balanced top coating suitability, the coating composition having low VOC, dryability and excellent coatability.SOLUTION: A low-VOC anticorrosive coating composition comprises a bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, an amine-based hardener (B) having a cyclic structure, a silane coupling agent (C) having an epoxy group, and a flat pigment (D) and/or a pigment (E) other than the flat pigment (D). The content of the silane coupling agent (C) is 5-20 mass%. The low-VOC anticorrosive coating composition satisfies the following (I) or (II). (I) The mass ratio between the (A) and the (C) is 1.0:0.1-0.5. (II) Two or more of the (B) are contained.SELECTED DRAWING: None

Description

The present invention relates to a low VOC coating composition, an anticorrosion coating film, a base material with a coating film, and a method for producing a base material with a coating film.

Conventionally, for a paint composition that forms a coating film having excellent oil resistance, solvent resistance, chemical resistance, and corrosion resistance, which is applied to the inner surface of a product carrier tank or a land tank in which chemicals are similarly stored. , Solid bisphenol A type epoxy resin, solid novolak type epoxy resin, and epoxy modified products such as diethylenetriamine epoxy adduct are used (blended).

Such a coating composition contains a relatively high molecular weight resin in order to impart the above-mentioned effect to the obtained coating film. Therefore, the coating composition contains a large amount of volatile organic components (hereinafter, VOC: Volatile Organic Compounds) from the viewpoint of coating workability and the like. Therefore, a paint using a semi-solid epoxy resin capable of further reducing VOC has been developed, but the amount of VOC reduction is not yet sufficient.

For example, Patent Document 1 contains a main agent component containing a bisphenol type epoxy resin having an epoxy equivalent of 250 to 300, and a curing agent component containing a xylylenediamine epoxy adduct and a polyamide epoxy adduct. A solid type anticorrosion coating composition is disclosed.

Patent Document 2 describes a bisphenol type liquid epoxy resin having two or more epoxy groups in one molecule and an epoxy equivalent of less than 250, xylene diamine or isophorone diamine as an epoxy resin as a coating material layer for covering the surface layer of a steel material. Disclosed are layers containing modified amines and pigments modified with.

Patent Document 3 discloses an anticorrosion coating composition comprising a first agent containing a bisphenol A type epoxy resin, a specific amine-based curing agent, and a second agent containing a monoepoxiside compound.

In Patent Document 4, an epoxy resin having an epoxy equivalent of 400 to 2200 is used from the viewpoint of heat resistance and water adhesion, and 10 to 40 parts by weight of a silane coupling agent is used with respect to 100 parts by weight of the solid content of the epoxy resin. A heat-resistant water-resistant coating composition containing 250 to 500 parts by weight of flat talc having an oil absorption of 40 ml / 100 g or less and 0 to 50 parts by weight of a coloring pigment is disclosed.

Patent Document 5 describes an epoxy functional resin suitable for coating a metal or concrete surface of a chemical apparatus, an amine curing agent for the epoxy functional resin, and an organic selected from the group of organosilanes and organosiloxanes. A coating composition containing a silicon-containing compound, wherein the molar ratio of the silicon atom to the epoxy group of the organic silicon-containing compound in the coating composition is 0.25 to 0.75: 1.00, preferably 0. Coating compositions in the range of 25-0.75: 1.00 are disclosed.

Further, conventionally, (large) steel structures such as ships, bridges, tanks, plants, marine buoys, and underwater pipelines are coated with a coating film obtained from an epoxy resin-based anticorrosive coating composition in order to prevent corrosion. .. On such a coating film, various resin-based topcoat coating compositions are used to impart functions such as aesthetics, weather resistance, corrosion resistance, and stain resistance, depending on the use and purpose of the steel structure. The object is painted and a top coat is formed.

International Publication No. 2007/102587 Japanese Unexamined Patent Publication No. 3-275773 Japanese Patent No. 5913762 Japanese Unexamined Patent Publication No. 60-118756 Special Table 2017-508598 Gazette

However, the coating material layer described in Patent Document 2 is inferior in oil resistance, solvent resistance and chemical resistance, and in particular, a solvent such as dichloroethane (EDC), methyl ethyl ketone (MEK) and benzene and room temperature (15 to 25 ° C.) , The same shall apply hereinafter.) It was found that there is a problem with solvent resistance such as blistering.
Further, it was found that the coating film obtained from the anticorrosion coating composition described in Patent Document 3 has a low crosslink density and is inferior in solvent resistance and chemical resistance.

As described in Patent Document 1, paint compositions capable of forming a coating film having excellent oil resistance, solvent resistance, chemical resistance and corrosion resistance are known, but these coating compositions A solid or semi-solid epoxy resin is used for. Similarly, a solid epoxy resin is used in the heat-resistant water-resistant coating composition described in Patent Document 4.

Further, only the composition using the novolak type epoxy resin as the epoxy resin or the composition having a large content of the silane coupling agent is described in Patent Document 5. Photochemicals require a large amount of solvent or epoxy group-containing reactive diluent in order to prepare a coating composition using such a novolak type epoxy resin into a coating composition having appropriate coating workability. It has been found that it is difficult to obtain a coating composition having a low VOC content that causes smog and the like, having excellent coating workability, and having excellent various performances.
Furthermore, a composition having a high content of a silane coupling agent produces alcohol by a hydrolysis reaction during storage or when a coating film is formed, which imposes a heavy burden on the environment and painters, and cannot be put into practical use. ..

When a conventional coating composition as described in Patent Document 1 is used for painting the inner surface of a closed structure such as a product carrier tank or a land tank in which chemicals are similarly stored. There is a high risk of fire due to the filling of the tank with VOCs, and the painters are also exposed to high concentrations of VOCs, which causes great health damage to the painters. Further, in painting these structures, spray painting, particularly airless spraying, is desirable from the viewpoint of work efficiency, so that a paint composition having a low paint viscosity and good painting workability is required. ing.

On the other hand, the conventional undercoat coating film formed from the epoxy resin-based coating composition is inferior in weather resistance, and therefore has the interlayer adhesion with the topcoat coating film and the physical properties exhibited by the laminate with the topcoat coating film (eg, blister resistance). ), Etc., it was found that the compatibility with topcoat coating tends to decrease. In particular, it has been found that when the period from the undercoat coating to the topcoat coating of the epoxy resin-based coating composition is long, there arises a problem that the interlayer adhesion between the formed undercoat coating film and the topcoat coating film becomes insufficient.

One embodiment of the present invention is a coating composition capable of forming a coating film having excellent oil resistance, solvent resistance, chemical resistance and corrosion resistance, and a coating film having excellent balance of topcoat coating compatibility in addition to these performances. A coating composition capable of forming a coating composition having a low VOC (that is, a high content of non-volatile components and no or almost no volatile organic components), and excellent drying property and coating workability. I will provide a.

As a result of diligent studies on a method for solving the above-mentioned problems, the inventor has found that the above-mentioned problems can be solved by a coating composition having a specific composition, and has completed the present invention.
The configuration example of the present invention is as follows.

<1> The silane coupling agent containing a bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, an amine-based curing agent (B) having a cyclic structure, and a silane coupling agent (C) having an epoxy group. The content of the agent (C) is 5 to 20% by mass, and the mass ratio of the bisphenol type epoxy compound (A) to the silane coupling agent (C) is 1.0: 0.1 to 0.5. A low VOC paint composition.

<2> A bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, an amine-based curing agent (B) having a cyclic structure, and a silane coupling agent (C) having an epoxy group are contained, and the cyclic structure is formed. A low VOC coating composition containing two or more kinds of amine-based curing agents (B) having an epoxy-based curing agent (B) and having a content of the silane coupling agent (C) of 5 to 20% by mass.

<3> The coating composition according to <1> or <2>, which further contains a flat pigment (D).

<4> The coating composition according to any one of <1> to <3>, wherein the silane coupling agent (C) is a silane coupling agent having one epoxy group in one molecule.

<5> Any of <1> to <4>, wherein the amine-based curing agent (B) having a cyclic structure contains at least one selected from an alicyclic amine and a modified product of an alicyclic amine. The described paint composition.

<6> A flat pigment (D) and a pigment (E) other than the flat pigment (D) are contained.
The coating composition according to any one of <1> to <5>, wherein the volume concentration (PVC) of the flat pigment (D) and the pigment (E) in the coating composition is 10 to 70%.

<7> The coating composition according to any one of <1> to <6>, wherein the VOC content of the coating composition is 200 g / L or less.

<8> An anticorrosion coating film formed from the coating composition according to any one of <1> to <7>.
<9> A substrate with a coating film containing the anticorrosion coating film and the substrate according to <8>.
<10> A method for producing a substrate with a coating film, which comprises the following steps [1] and [2].
[1] A step of applying the coating composition according to any one of <1> to <7> on a substrate [2] A step of drying the coated coating composition to form a coating film.

According to one embodiment of the present invention, a coating composition capable of forming a coating film having excellent oil resistance, solvent resistance, chemical resistance and corrosion resistance, and in addition to these performances, excellent in a good balance of topcoat coating compatibility. A coating composition capable of forming a coating film, which has a low VOC and is excellent in drying property and coating workability, particularly spray coating workability, can be obtained.
Further, according to one embodiment of the present invention, it is possible to form a coating film having the above-mentioned excellent various performances on various base materials (for example, various tanks).

FIG. 1 is a schematic view of a test plate with a notch used in the anticorrosion test of Examples.

≪Low VOC paint composition≫
The low VOC coating composition (hereinafter, also referred to as “the present composition”) according to an embodiment of the present invention is a bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, and an amine-based curing agent (B) having a cyclic structure. ), And the silane coupling agent (C) having an epoxy group, the content of the silane coupling agent (C) is 5 to 20% by mass, and the following (I) or (II) is satisfied.
(I) Composition 1 having a mass ratio of the bisphenol type epoxy compound (A) to the silane coupling agent (C) of 1.0: 0.1 to 0.5, or
(II) Composition 2 containing two or more kinds of amine-based curing agents (B) having the cyclic structure.
Is.

The composition 1 contains the above (A) to (C), and in particular, contains a specific amount of (C) and contains (A) and (C) in a specific amount ratio, and thus the composition. 2 contains the above-mentioned (A) to (C), and in particular, contains two or more specific types of curing agents and contains a specific amount of (C), so that the above effect is exhibited.
The compositions 1 and 2 exert the above-mentioned effects, respectively, but the composition 1 is particularly excellent in oil resistance, chemical resistance and solvent resistance, and the composition 2 is particularly corrosion-proof (particularly electric corrosion-proof). Excellent in drying property, coating workability and topcoat coating compatibility.

Here, excellent in oil resistance, solvent resistance, and chemical resistance specifically means oils such as heavy oil, gasoline, naphtha, palm oil, methanol, ethanol, xylene, benzene, methyl isobutyl ketone, 1, 2-It means that it has excellent resistance to solvents such as dichloroethane and ethyl acetate, and chemicals such as sodium hydroxide and sulfuric acid.
Since these oils, solvents and chemicals have a large effect on the coating film, the coating film resistant to these oils, solvents and chemicals is also resistant to general oils, solvents and chemicals. It is thought that.

Since it is particularly important to prevent corrosion of the base material, a preferred example of this composition is "anticorrosive paint composition", but the composition is used only for imparting anticorrosive properties to the base material. The composition is not limited to, and is used to impart oil resistance, solvent resistance, chemical resistance, etc. to the base material, and the base material and the base material, or the base material and the top coat. An adhesive for adhering to and is also included in one aspect of the present composition.

In the present invention, the term "low VOC" refers to the present composition when the composition is adjusted to have a viscosity suitable for coating, with no or almost no VOC such as a solvent. It means that the VOC content in the medium is 200 g / L or less.
The VOC content in the present composition is preferably 170 g / L or less, more preferably 155 g / L or less.

The VOC content of this composition can be calculated from the following formula (1) using the values of the following paint specific gravity and mass NV.
VOC content (g / L) = paint specific density x 1000 x (100-mass NV) / 100 ... (1)

Paint specific density (g / cm ³ ): Under a temperature condition of 23 ° C., the present composition (eg, the composition immediately after mixing the main agent component and the curing agent component) is filled in a specific gravity cup having an internal volume of 100 ml. Value calculated by weighing the mass of the composition

Mass NV (% by mass): Weigh 1 g of this composition (eg, the composition immediately after mixing the main ingredient and the curing agent component) on a flat-bottomed dish, spread it evenly using a wire of known mass, and at 23 ° C. After leaving it for 24 hours, it is dried at 110 ° C. for 1 hour, and the value of the mass percentage calculated by weighing the heating residue (also referred to as “solid content” or “nonvolatile content”) and the wire (the present composition). Content of heating residue (mass NV) in the container)

The present composition may be a one-component type composition, but usually has two components consisting of a main component containing an epoxy compound (A) and a curing agent component containing an amine-based curing agent (B). The composition of the mold. Further, if necessary, the present composition may be a composition having three or more components.
These main agent components and curing agent components are usually stored, stored, transported, etc. in separate containers, and are mixed and used immediately before use.

<Bisphenol type epoxy compound (A)>
The bisphenol type epoxy compound (A) includes, for example, a polymer or oligomer having a bisphenol structure in the molecule and containing two or more epoxy groups, and a polymer or a polymer produced by a ring-opening reaction of the epoxy groups. Examples include oligomers.
By using such an epoxy compound (A) together with the specific (B) and (C), a composition having a low VOC and excellent coating workability can be obtained, and further, according to the composition, oil resistance. , A coating film having excellent solvent resistance, chemical resistance and corrosion resistance can be formed.
As the epoxy compound (A), one kind may be used, or two or more kinds may be used.

The epoxy equivalent of the epoxy compound (A) is 200 or less, preferably 100 to 200, more preferably 100 to 190, because a coating film having excellent oil resistance, solvent resistance, chemical resistance, corrosion resistance and the like can be formed. It is more preferably 100 to 180, and particularly preferably 100 to 175. The epoxy equivalent is calculated based on JIS K 7236.
Epoxy compounds having an epoxy equivalent of more than 200 have an excessively large molecular weight. Therefore, when such an epoxy compound is used, a solvent for adjusting the appropriate viscosity for coating is often required, which facilitates a low VOC coating composition. It tends to be impossible to obtain.

The epoxy compound (A) is preferably an epoxy resin that is liquid at room temperature, and examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, and bisphenol AD type epoxy resin.

As the epoxy compound (A), a commercially available product may be used, and the commercially available product includes, for example, "E-028" (manufactured by Akishin Otake Chemical Corporation, epoxy equivalent 180 to 190) which is a bisphenol A type epoxy resin. , 100% non-volatile content), "jER 807" (manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 160-175, 100% non-volatile content), which is a bisphenol F type epoxy resin.

The viscosity (25 ° C.) measured by an E-type viscometer (FMD type manufactured by TOKIMEC) of the epoxy compound (A) has a lower limit of preferably 1500 mPa · s, more preferably 3000 mPa · s, and an upper limit of preferably 3000 mPa · s. Is 120,000 mPa · s, more preferably 30,000 mPa · s.
In the following, for example, a lower limit of preferably 10 means that the preferred range is 10 or more, and an upper limit of preferably 100 means that the preferred range is 100 or less.

The content of the epoxy compound (A) in the present composition is such that a coating film having excellent adhesion to a substrate, oil resistance, solvent resistance, chemical resistance, corrosion resistance and the like can be easily obtained. Therefore, the lower limit is preferably 10% by mass, more preferably 15% by mass, and the upper limit is preferably 50% by mass, more preferably 45% by mass with respect to 100% by mass of the non-volatile content of the present composition. ..

<Amine-based curing agent (B) having a cyclic structure>
The amine-based curing agent (B) having a cyclic structure is not particularly limited as long as it is an amine having a cyclic structure, but is preferably a low VOC type compound, and preferably a polyamine.
Examples of the curing agent (B) include polyamines such as alicyclic, aromatic, and heterocyclic polyamines, modified products of these polyamines, and Mannig compounds using aliphatic polyamines and phenolic compounds (eg, phenalkamine). ) And an adduct of an aliphatic polyamine and an epoxy compound having an aromatic ring structure (eg, a bisphenol A type epoxy compound).
The curing agent (B) used in the composition 2 may be two or more kinds, and the curing agent (B) used in the composition 1 may be one kind or two or more kinds.

Specific examples of the alicyclic polyamine include 1,4-cyclohexanediamine, diaminodicyclohexylmethane (particularly 4,4'-methylenebiscyclohexylamine), and 2,2'-dimethyl-4,4'. -Methylenebiscyclohexylamine, 4,4'-isopropylidenebiscyclohexylamine, norbornandiamine, bis (aminomethyl) cyclohexane, isophoronediamine, mensendiamine (MDA), 2,5-di (4-aminocyclohexylmethyl) cyclohexyl Amine, 4- (p-aminobenzyl) cyclohexylamine, 2,4'-bis (4''-aminocyclohexyl) -2', 4-methylenedianiline, 4-[(4-aminocyclohexyl) methyl] -N − [4-[(4-Aminocyclohexyl) methyl] cyclohexyl] −cyclohexylamine, 2,4-di (4-aminocyclohexylmethyl) aniline, 2,5-di (4-aminocyclohexylmethyl) aniline and the like.

Examples of the aromatic polyamine include bis (aminoalkyl) benzene, bis (aminoalkyl) naphthalene, and compounds having two or more primary amino groups bonded to a benzene ring.
Specific examples of this aromatic polyamine include o-xylylenediamine, m-xylylenediamine (MXDA), p-xylylenediamine, phenylenediamine, naphthalenediamine, diaminodiphenylmethane, and 2,2-bis (. 4-Aminophenyl) Propane, 4,4'-diaminodiphenyl ether, 4,4'-diaminobenzophenone, 4,4'-diaminodiphenylsulfone, 3,3'-dimethyl-4,4'-diaminodiphenylmethane, diaminodiethylphenyl Methane, 2,4'-diaminobiphenyl, 2,3'-dimethyl-4,4'-diaminobiphenyl, 3,3'-dimethoxy-4,4'-diaminobiphenyl, bis (aminomethyl) naphthalene, bis (amino) Ethyl) Naphthalene can be mentioned.

Specific examples of the heterocyclic polyamine include 1,4-bis (3-aminopropyl) piperazine, 1,4-diazacycloheptane, 1- (2'-aminoethylpiperazine), and 1-. [2'-(2''-aminoethylamino) ethyl] piperazine, 1,11-diazacycloeikosan, 1,15-diazacyclooctacosane can be mentioned.

Examples of the modified products of polyamines such as alicyclic, aromatic, and heterocyclic products include Mannig modified products, epoxy adducts, styrene modified products, and fatty acid modified products of the polyamines.

Examples of the aliphatic polyamine include alkylene polyamines, polyalkylene polyamines, and alkylaminoalkylamines.

Examples of the alkylene polyamine include _{compounds represented by the formula: "H 2} N-R ^1- NH ₂ " (R ¹ is a divalent hydrocarbon group having 1 to 12 carbon atoms). Specifically, for example, methylenediamine, ethylenediamine, 1,2-diaminopropane, 1,3-diaminopropane, 1,4-diaminobutane, 1,5-diaminopentane, 1,6-diaminohexane, 1,7. Examples thereof include −diaminoheptane, 1,8-diaminooctane, 1,9-diaminononane, 1,10-diaminodecane and trimethylhexamethylenediamine.

Examples of the polyalkylene polyamine include the formula: "H ₂ N- (C _m H _2m NH) _n H" (m is an integer of 1 to 10. n is 2 to 10, preferably 2 to 6). ), Specifically, for example, diethylenetriamine, dipropylenetriamine, triethylenetetramine, tripropylenetetramine, tetraethylenepentamine, tetrapropylenepentamine, pentaethylenehexamine, etc. Examples include nonaethylenedecamine and bis (hexamethylene) triamine.

Examples of aliphatic polyamines other than these include tetra (aminomethyl) methane, tetrakis (2-aminoethylaminomethyl) methane, 1,3-bis (2'-aminoethylamino) propane, and 2,2'-[. Ethylenebis (iminotrimethyleneimino)] bis (ethaneamine), tris (2-aminoethyl) amine, bis (cyanoethyl) diethylenetriamine, polyoxyalkylene polyamine (particularly, diethyleneglycolbis (3-aminopropyl) ether) can be mentioned.

Among these polyamines, alicyclic polyamines and modified products thereof are preferable, and polyamines having a cyclohexylamine ring are more preferable, because a coating film having excellent solvent resistance and chemical resistance can be easily obtained. More preferably, it contains 4,4'-methylenebiscyclohexylamine, 2,2'-dimethyl-4,4'-methylenebiscyclohexylamine, di (4-aminocyclohexylmethyl) aniline or a modification thereof. , 2'-dimethyl-4,4'-methylenebiscyclohexylamine, di (4-aminocyclohexylmethyl) aniline or variants thereof are more preferred, and di (4-aminocyclohexylmethyl) aniline or modifications thereof. It is particularly preferable to include a substance.

When the present composition contains two or more kinds of curing agents (B), particularly the composition 2 is excellent in corrosion resistance (particularly electrocorrosion resistance) and drying property, and the like can be easily obtained. , Preferably containing a curing agent (B1) selected from alicyclic polyamines and modified products thereof, containing two or more types of curing agents (B1), or a curing agent (B1) and m-xylylene diamine and It is more preferable to contain a curing agent (B2) selected from the modified product, and to contain an alicyclic polyamine (B1-1) and a modified product of an alicyclic polyamine (B1-2), or a curing agent. It is more preferable to contain (B1) and a curing agent (B2).
The curing agents (B1) and (B1-1) preferably contain di (4-aminocyclohexylmethyl) aniline.
Examples of the modified products in the curing agents (B1), (B2) and (B1-2) include Mannich modified products, epoxy adducts, styrene modified products or fatty acid modified products.

The content of the curing agents (B1) and (B2) in the curing agent (B) in the present composition is not particularly limited, but has oil resistance, solvent resistance, chemical resistance, corrosion resistance and topcoat coating compatibility. Considering the balance, the content of the curing agent (B1) is preferably 20% by mass or more, more preferably 30% by mass or more, based on 100% by mass of the curing agent (B). The content of the curing agent (B1-1) is preferably 30% by mass or more, more preferably 40% by mass or more, and particularly preferably 50% by mass or more with respect to 100% by mass of the curing agent (B1). ..

As the alicyclic polyamine, a commercially available product may be used, and examples of the commercially available product include "ankamine 2280", "ankamine 2049" and "ankamine 2143" (all manufactured by Air Products Co., Ltd.). In particular, "ankamine 2280" containing di (4-aminocyclohexylmethyl) aniline as a main component can be preferably used.

<Silane coupling agent (C) having an epoxy group>
The silane coupling agent (C) having an epoxy group has an epoxy group and an alkoxy group from the viewpoint that a coating film having excellent oil resistance, solvent resistance, chemical resistance, corrosion resistance and the like can be easily formed. A compound is preferable, an alkoxy group-containing silane coupling agent having one epoxy group in one molecule is more preferable, and a compound represented by the following formula is particularly preferable.
X-SiMe _n Y _3-n
[N is 0 or 1, and X is an epoxy group, a group in which a part of the hydrocarbon group is substituted with an epoxy group, or a part of a group in which a part of the hydrocarbon group is substituted with an ether bond or the like. A group substituted with an epoxy group is shown, Me is a methyl group, and Y is an alkoxy group such as a methoxy group or an ethoxy group. ]

The silane coupling agent (C) has a function of chemically binding a flat pigment (D) or a pigment (E), which will be described later, with a coating film-forming component such as the following epoxy component or the following amine component, and also has a function of chemically bonding. It has the effect of improving the adhesion of the formed coating film to the substrate.
Since the silane coupling agent (C) has an epoxy group, a coating film exhibiting the above effect can be obtained. On the other hand, when only a silane coupling agent having no epoxy group is used, the desired effect is not obtained.
As the silane coupling agent (C), one kind may be used, or two or more kinds may be used.

Specific examples of the silane coupling agent (C) include (3,4-epoxycyclohexyl) ethyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBM303”, etc.), γ-glycidoxypropyl. Trimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., "KBM403", etc.) is preferable, and in addition, γ-glycidoxypropylmethyldimethoxysilane (manufactured by Toray Dow Corning Co., Ltd., "AY43-026", etc.), γ-glycidoxypropylmethyldiethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., “KBE-402”, etc.) may be used.

The content of the silane coupling agent (C) in the composition 1 is the total amount of the composition 1 from the viewpoint that a coating film having excellent solvent resistance, chemical resistance and corrosion resistance can be easily obtained. The lower limit is preferably 5% by mass, more preferably 7% by mass, and the upper limit is preferably 20% by mass, more preferably 15% by mass with respect to 100% by mass.
The content of the silane coupling agent (C) in the composition 2 is such that a composition having excellent coating workability can be easily obtained, and solvent resistance, chemical resistance, corrosion resistance and topcoat coating compatibility. From the viewpoint that a coating film having better properties can be easily obtained, the content is 5 to 20% by mass, preferably 5 to 10% by mass, based on 100% by mass of the total amount of the composition 2.
When the content of the silane coupling agent (C) is less than 5% by mass or more than 20% by mass with respect to 100% by mass of the present composition, the corrosion resistance and the adhesion to the substrate are good. However, there is a tendency that a coating film having excellent solvent resistance and chemical resistance cannot be obtained.

The lower limit of the mass of the silane coupling agent (C) with respect to 1.0 part by mass of the epoxy compound (A) in the composition 1 is preferably 0.1 part by mass, more preferably 0.2 part by mass. The upper limit is preferably 0.5 parts by mass, more preferably 0.45 parts by mass.
In the composition 1, when the mass of the silane coupling agent (C) with respect to 1.0 part by mass of the epoxy compound (A) is less than 0.1 part by mass, a coating film having excellent solvent resistance and chemical resistance is obtained. If it exceeds 0.5 parts by mass, it tends not to be obtained, and if it exceeds 0.5 parts by mass, a composition having excellent drying property tends not to be obtained.
In particular, in the above composition 1, when the mass of the silane coupling agent (C) with respect to 1.0 part by mass of the epoxy compound (A) exceeds 0.5 parts by mass, the silane coupling agent (C) is alkoxy. In the case of a compound having a group, the alkoxy group in the silane coupling agent (C) undergoes a hydrolysis reaction to generate alcohol, so that the composition has a large load on the environment at the time of coating film formation and the coating operator. It tends to be a thing.
The mass of the silane coupling agent (C) with respect to 1.0 part by mass of the epoxy compound (A) in the composition 2 is the same as that of the composition 1 for the same reason as in the case of the composition 1. It is preferably in the range.

<Flat pigment (D)>
The present composition preferably contains a flat pigment (D) from the viewpoints of being able to easily obtain a coating film having excellent anticorrosion properties and excellent adhesion to a substrate due to internal stress relaxation.
As the flat pigment (D), one kind may be used, or two or more kinds may be used.

As the flat pigment (D), the median diameter (D50) is preferably 30 to 200 μm and the average aspect ratio (median diameter / average thickness) is preferably 30 to 200 μm from the viewpoint that a coating film having a more excellent effect can be formed. The pigment is preferably 10 or more, more preferably 20 or more, preferably 150 or less, and more preferably 100 or less.
The D50 can be measured using a laser scattering diffraction type particle size distribution measuring device, for example, "SALD 2200" (manufactured by Shimadzu Corporation).
The average thickness is observed from the horizontal direction with respect to the main surface of the flat pigment (D) using a scanning electron microscope (SEM), for example, "XL-30" (manufactured by Philips). It can be calculated as an average value of the thicknesses of individual pigment particles.

Examples of the flat pigment (D) include mica, glass flakes, aluminum flakes, scaly iron oxide, stainless steel flakes, and plastic flakes, which are inexpensive, easily available, and form a coating film having more excellent effects. Mica is preferable because it can be used.
Examples of the mica include "mica powder 100 mesh" (manufactured by Fukuoka Tarku Kogyo Co., Ltd., D50: 41 μm, average aspect ratio: 35) and the like.

When the present composition contains a flat pigment (D), the content of the flat pigment (D) in the present composition is such that an excellent coating film can be easily obtained due to the above-mentioned effect. The lower limit is preferably 1% by mass, more preferably 3% by mass, and the upper limit is preferably 40% by mass, more preferably 20% by mass with respect to 100% by mass of the non-volatile content of the product.

<Pigment (E)>
The present composition may contain a pigment (E) other than the flat pigment (D), and examples of the pigment (E) include extender pigments, coloring pigments, rust preventive pigments, etc., which are organic or inorganic. It may be any of the systems.
As the pigment (E), one kind may be used, or two or more kinds may be used.

As the extender pigment, for example, conventionally known talc, (precipitating) barium sulfate, (potassium) feldspar, kaolin, alumina white, clay, magnesium carbonate, barium carbonate, calcium carbonate, dolomite, and silica can be used. .. In particular, talc, silica, (precipitating) barium sulfate, and (potassium) feldspar are preferred.

When such an extender pigment is blended in the present composition, the blending amount thereof is preferably 10 to 70% by mass, more preferably 10 to 50% by mass, based on 100% by mass of the non-volatile content of the present composition. ..

As the coloring pigment, for example, conventionally known inorganic pigments such as carbon black, titanium dioxide (titanium white), iron oxide (valve handle), yellow iron oxide, and ultramarine, and organic pigments such as cyanine blue and cyanin green are used. be able to. In particular, titanium white, carbon black, and valve handle are preferable.

When such a coloring pigment is blended in the present composition, the blending amount thereof is preferably 1 to 30% by mass, more preferably 1 to 10% by mass, based on 100% by mass of the non-volatile content of the present composition. ..

When the present composition contains the flat pigment (D) and / or the pigment (E), the volume concentration (PVC) of all these pigments can easily obtain a composition having excellent coating workability. It is preferably 10 to 70%, more preferably 10 to 50%, and particularly preferably 10 to 40, from the viewpoints that a coating film having excellent adhesion to a substrate and water resistance by stress relaxation can be easily obtained. %.
If the PVC is below the above range, the corrosion resistance of the obtained coating film tends to be deteriorated and the effect of stress relaxation tends to be poor, and if it exceeds the above range, the water resistance of the obtained coating film is lowered and the painting work is performed. The sex tends to decrease.
The PVC refers to the total volume concentration of the pigment with respect to the volume of the non-volatile component in the present composition. Specifically, PVC can be obtained from the following formula.
PVC [%] = total volume of all pigments in this composition x 100 / volume of non-volatile content in this composition

The non-volatile content (solid content) of the present composition means the mass percentage of the coating film (heated residue) after the composition is sufficiently reactively cured (heated), or the coating film (heated residue) itself. do. For the non-volatile content, 1 ± 0.1 g of the present composition (for example, the composition immediately after mixing the main agent component and the curing agent component) is weighed on a flat bottom dish according to JIS K 5601-1-2, and a wire having a known mass is used. It can be calculated by measuring the heating residue and the mass of the wire when it is spread evenly using a wire, dried at 23 ° C for 24 hours, and then heated at a heating temperature of 110 ° C for 1 hour (under normal pressure). can. The non-volatile content is a value equivalent to the total amount of solid content (components other than the solvent) of the raw material components used in the present composition.

The volume of the non-volatile component in the present composition can be calculated from the mass and the true density of the non-volatile component of the present composition. The mass and true density of the non-volatile component may be measured values or values calculated from the raw materials used.
The volume of the pigment can be calculated from the mass and true density of the pigment used. The mass and true density of the pigment may be measured values or values calculated from the raw materials used. For example, it can be calculated by separating the pigment from other components from the non-volatile content of the present composition and measuring the mass and true density of the separated pigment.

<Other ingredients>
In the present composition, other components include an epoxy compound other than the epoxy compound (A), an amine-based curing agent other than the curing agent (B), and a silane coupling agent other than the silane coupling agent (C). Addition of various additives such as anti-sagging agent (precipitation inhibitor), fiber substance, surfactant (eg, surfactant described in JP-A-2-298563), dispersant, leveling agent, surface conditioner, organic solvent, etc. The agent can be appropriately blended.
One of these may be used, or two or more thereof may be used.
The other components may be added to the main agent component or may be added to the curing agent component.

The present composition may contain an epoxy compound other than the epoxy compound (A). Examples of such epoxy compounds include novolak type epoxy resin, hydrogenated bisphenol A type epoxy resin, hydrogenated bisphenol F type epoxy resin, hydrogenated novolak type epoxy resin, aliphatic type epoxy resin, and aromatic type epoxy resin. Epoxy group-containing reactive diluents can be mentioned.
Further, a bisphenol type epoxy compound having an epoxy equivalent of more than 200 may be used.

In particular, in terms of easily forming a coating film having excellent solvent resistance and chemical resistance, it is preferable to use a novolak type epoxy resin or a polyfunctional epoxy group-containing reactive diluent, which is more excellent in topcoat coating compatibility. It is preferable to use a monofunctional epoxy group-containing reactive diluent from the viewpoint that a coating film can be easily formed. In particular, the polyfunctional epoxy group-containing reactive diluent and the monofunctional epoxy group-containing reactive diluent are used from the viewpoint of easily forming a coating film having a good balance between chemical resistance and topcoat coating compatibility. It is preferable to use them together.
The monofunctional epoxy group-containing reactive diluent means a reactive diluent having one epoxy group, and the polyfunctional epoxy group-containing reactive diluent has two or more epoxy groups. A reactive diluent.

When a reactive diluent is used in combination, the mass of the monofunctional epoxy group-containing reactive diluent in the present composition with respect to 1 part by mass of the polyfunctional epoxy group-containing reactive diluent has a lower limit, preferably 0.1. It is by mass, more preferably 0.2 parts by mass, particularly preferably 0.3 parts by mass, and the upper limit is preferably 3 parts by mass, more preferably 2 parts by mass, and particularly preferably 1.5 parts by mass.

The epoxy group-containing reactive diluent is not particularly limited as long as it is an epoxy compound having a viscosity at 25 ° C. of 500 mPa · s or less.
Examples of the monofunctional epoxy group-containing reactive diluent include alkyl glycidyl ether (1 to 13 carbon atoms of the alkyl group), phenyl glycidyl ether, o-cresyl glycidyl ether, and alkylphenyl glycidyl ether (the number of carbon atoms of the alkyl group). 1-20, preferably 1-5, eg, methylphenyl glycidyl ether, ethylphenyl glycidyl ether, propylphenyl glycidyl ether, p-tert-butylphenyl glycidyl ether), phenol glycidyl ether, alkylphenol glycidyl ether, phenol (EO) _n Glycidyl ether (repetition number n = 3 to 20, EO: -C ₂ H ₄ O-) can be mentioned.
Examples of the polyfunctional epoxy group-containing reactive diluent include 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, and resorcinol. Diglycidyl ether, mono or polyalkylene glycol diglycidyl ether (alkylene group carbon number 1-5, eg ethylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether), trimethylolpropane triglycidyl ether Can be mentioned.
Among the epoxy group-containing reactive diluents, neopentyl glycol diglycidyl ether, phenol glycidyl ether, o-cresyl glycidyl ether, p. -Tert-Butylphenylglycidyl ether is preferred.

As the epoxy compound other than the epoxy compound (A), a commercially available product may be used, and the commercially available product is, for example, "DEN 425" (manufactured by The Dow Chemical Company), which is a novolak type epoxy resin. , Epoxy equivalent 169-175, 100% non-volatile content), "DEN 431" (manufactured by The Dow Chemical Company, epoxy equivalent 172-179, 100% non-volatile content) and "DEN 438". (The Dow Chemical Company, Epoxy Equivalent 176-181, Epoxy Equivalent 100%), Epoxy Group-Containing Reactive Diluting Agent "ERISYS GE-10" (o-cresylglycidyl ether, CVC Thermoset Specialties, Epoxy Equivalent) 170-195, 100% non-volatile content, viscosity 8 mPa · s / 25 ° C.), "ERISYS GE-20" (neopentyl glycol diglycidyl ether, manufactured by CVC Thermoset Specialties, epoxy equivalent 125-137, 100% non-volatile content, viscosity. 14 mPa · s / 25 ° C.), "Cardolite 2513HP" (manufactured by Cardolite, epoxy equivalent 413, non-volatile content 100%, viscosity 30 mPa · s / 25 ° C.).

When the epoxy compound (A) and an epoxy compound other than the epoxy compound (A) are used in combination, the content of the epoxy compound other than the epoxy compound (A) is preferably 100 parts by mass of the epoxy compound (A). Is 1 to 85 parts by mass.

The present composition may contain an amine-based curing agent other than the curing agent (B). Examples of such an amine-based curing agent include the aliphatic polyamines, preferably polyoxyalkylene polyamines, polyalkylene polyamines, and modified products thereof.
Examples of the modified product include Mannich modified product, epoxy adduct or fatty acid modified product.
As the amine-based curing agent other than the curing agent (B), a commercially available product may be used, and the commercially available product is, for example, "Jeffamine D-230" (Huntsman Japan Co., Ltd.) which is a polyoxypropylene diamine. (Manufactured by), "Ancamide 506" (manufactured by Air Products Co., Ltd.), which is a fatty acid modified product of tetraethylenepentamine.

In the present composition, the epoxy compound (A) and an epoxy compound other than the epoxy compound (A) (hereinafter, these are also collectively referred to as “epoxy component”), and the curing agent (B) and the curing agent. The total content of amine-based curing agents other than (B) (hereinafter, collectively referred to as "amine components") has a high cross-linking density and is excellent in oil resistance, solvent resistance, chemical resistance, water resistance, etc. From the viewpoint that an excellent coating film can be easily obtained, the lower limit is preferably 20% by mass, more preferably 30% by mass, and the upper limit is preferably 30% by mass with respect to 100% by mass of the non-volatile content of the present composition. It is 70% by mass, more preferably 65% by mass.

As for the content of the amine component in the present composition, a composition having excellent drying properties can be obtained, and a coating film having excellent oil resistance, solvent resistance, chemical resistance, water resistance and adhesion to a substrate can be easily obtained. The reaction ratio calculated by the following formula (2) is preferably 0.5 or more, more preferably 0.6 or more, preferably 1.3 or less, and more preferably. Is an amount of 1.0 or less.
Reaction ratio = (Amine component compounding amount / Amine component active hydrogen equivalent + Epoxy component compounding amount / Functional group equivalent of the epoxy component reactive component) / (Epoxy component Amount of compounding / epoxy equivalent of epoxy component + compounding amount of component having reactivity with amine component / functional group equivalent of component having reactivity with amine component) ... (2)

Here, examples of the "component having reactivity with the amine component" in the formula (2) include the silane coupling agent (C) and the like, and "reactivity with the epoxy component". Examples of the "component having" include silane coupling agents other than the silane coupling agent (C). Further, the "functional group equivalent" of each of the above components means the mass (g) per 1 mol functional group obtained by dividing the mass of 1 mol of these components by the number of mols of the functional groups contained therein. ..

Examples of the anti-sagging agent (precipitation inhibitor) include organic clay-based waxes such as stearate salts of Al, Ca, and Zn, lecithin salts, and alkyl sulfonates, polyethylene wax, amido wax, hydrogenated castor oil wax, and hydrogenated wax. Conventionally known waxes such as a mixture of castor oil wax and amido wax, synthetic fine powder silica, and polyethylene oxide wax can be used, but among them, amide wax, synthetic fine powder silica, polyethylene oxide wax, and organic clay wax are preferable.

Examples of such anti-sauce agents (precipitation preventive agents) include "Disparon 305", "Disparon 4200-20" and "Disparon 6650" manufactured by Kusumoto Kasei Co., Ltd .; "ASAT-250F" manufactured by Itoh Oil Chemicals Co., Ltd. Examples include products such as "Fronon RCM-300" manufactured by Kyoeisha Chemical Co., Ltd .; "Benton SD-2" manufactured by Sedimentis Specialties and Inc.

When a sagging preventive agent (precipitation inhibitor) is added to the present composition, it may be added to the main ingredient in an amount of, for example, 0.1 to 10% by mass.

The organic solvent is not particularly limited, and examples thereof include aromatic hydrocarbon solvents such as toluene and xylene, ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as butyl acetate, isopropanol and benzyl alcohol. Examples thereof include alcoholic solvents, mineral spirits, n-hexane, n-octane, 2,2,2-trimethylpentane, isooctane, n-nonane, cyclohexane, methylcyclohexane and other aliphatic hydrocarbon solvents.

[Manufacturing of low VOC paint composition]
The present composition is preferably produced by mixing and kneading the main agent component and the curing agent component, which are individually prepared in advance, at the time of use.

The main ingredient can be prepared by blending each of the constituents thereof, stirring and kneading. In that case, for example, it is preferable to use an SG mill or a high-speed disper to disperse the compounding components as uniformly as possible while keeping the temperature of the mill base at 55 to 60 ° C. for about 30 minutes.
On the other hand, the curing agent component may be mixed with each component constituting the curing agent component and uniformly dispersed by a stirrer, although it depends on the component to be blended.

[Use of paint composition]
According to this composition, it is possible to form a coating film (layer) having various performances such as oil resistance, solvent resistance, chemical resistance, water resistance and corrosion resistance. The anticorrosion also includes galvanic corrosion, galvanic corrosion, stress corrosion and the like.
This composition can be used for various purposes because it can form a coating film with these excellent performances, but it is a cargo tank for transporting chemical substances by land transportation, sea transportation, etc. (eg, product carriers and chemicals). (Tanker), the inner surface of a land tank for storing chemical substances, the inner surface of pipelines in contact with chemical substances, WBT (Water Ballast Tank), COT (Crude Oil Tank), FWT (Fresh Water Tank), DWT It is preferable to use it on the inner surface of tanks such as (Drinking Water Tank) and the inner and outer surfaces of ships, etc. In addition to this application, seawater desalination equipment, places where maintenance of marine structures is difficult, dams and water gates It is suitable for use around gates, piping for plants that use seawater / river water or industrial water as cooling water, and pools for storing used nuclear fuel.
In particular, the composition 1 is preferably used on the inner surface of a tank (eg, a product carrier or a chemical tanker) used for transporting or storing a chemical substance or the like, a pipeline or the like, and the composition 2 is preferably used. , It is preferable to use it as a universal primer for ships and the like.

The composition can also be used to repair and coat the surface of a corroded base material with an anticorrosive coating. That is, as an adhesive for applying the present composition to a welded portion of a base material such as stainless steel or a place having a gap to prevent local corrosion of the base material and further adhering a stainless steel plate to the surface of the coating film. By also acting, local corrosion can be stably suppressed for a long period of time.
In this way, when repairing the base material, for example, the present composition is applied to the surface of the base material having welded portions (welded lines) or gaps, and another base material is adhered to the surface of the uncured coating film. The present composition may be further applied on the other substrate.

≪Manufacturing method of coating film, substrate with coating film, substrate with coating film≫
The coating film according to one embodiment of the present invention (hereinafter, also referred to as “the present coating film”) is formed by using the present composition, and the base material with a coating film according to one embodiment of the present composition is It is a laminate containing the present coating film and the object to be coated (base material).
The material of the base material is not particularly limited, and examples thereof include steel (iron, steel, alloy iron, carbon steel, mild steel, alloy steel, stainless steel, etc.), non-ferrous metals (zinc, aluminum, etc.), and the base material. The surface may be coated with a shop primer or the like.
Further, when mild steel (SS400 or the like) is used as the base material, the surface is adjusted by polishing the surface with grit blast or the like, if necessary (eg, arithmetic average roughness (Ra) is about 30 to 75 μm). It is desirable to make adjustments so that

The dry film thickness of the present coating film is not particularly limited, but the lower limit is usually 50 μm, preferably 200 μm, and the upper limit is usually 500 μm from the viewpoint of obtaining a coating film having sufficient corrosion resistance and the like. It is preferably 400 μm.
As a method for forming the present coating film, a desired film thickness may be formed by one coating (one coating), or a coating film having a desired film thickness may be formed by two or more coatings (two or more coatings). May be formed. From the viewpoint of film thickness control and the residual organic solvent in the coating film, it is preferable to form the coating film so as to have a desired dry film thickness by two or more coatings.

The method for producing a substrate with a coating film according to an embodiment of the present invention (hereinafter, also referred to as “the present method”) includes the following steps [1] and [2].
Step [1]: Step of coating the present composition on the substrate Step [2]: Step of drying the painted coating composition to form a coating film.

<Step [1]>
The coating method in the step [1] is not particularly limited, and for example, the surface of the base material may be coated according to a conventional method such as airless spray coating, air spray coating, brush coating, roller coating, etc. When painting a large structure, spray painting is preferable from the viewpoint that a large-area base material can be easily painted.
In the painting work, the composition may be appropriately diluted with thinner (organic solvent) or the like before use. However, even when diluted in this way, the VOC content in the present composition is preferably 200 g / L or less.

The conditions for spray coating may be appropriately adjusted according to the dry film thickness to be formed. For example, in the case of airless spray, the primary (air) pressure: about 0.4 to 0.8 MPa, the secondary (paint). The pressure is preferably about 15 to 36 MPa, and the gun moving speed is preferably about 50 to 120 cm / sec.
Further, the coating film may be coated so that the dry film thickness of the obtained coating film is within the above range.

The viscosity of this composition suitable for spray coating is preferably 1500 to 7000 mPa · s, more preferably 1500 to 7000 mPa · s, under the measurement conditions of 23 ° C. using an E-type viscometer (FMD type, manufactured by TOKIMEC). It is 1500-4000 mPa · s.

<Step [2]>
The drying conditions in the step [2] are not particularly limited and may be appropriately set according to the method for forming the coating film, the type of the base material, the application, the coating environment, etc., for example, at 5 to 35 ° C. , 12-250 hours. Further, if desired, it may be forcibly dried and cured by heating and blowing, but usually it is dried and cured under natural conditions.

In addition, in the case of forming a coating film by the above-mentioned two or more coatings, particularly two times coating, after performing steps [1] and [2], on the obtained coating film, the steps [1] and [2] are performed. A coating film is formed by repeating a series of steps. Further, when the coating film is formed by three coats, the coating film is formed by repeating a series of steps on the two coats.

Hereinafter, preferred embodiments of the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples.

[Example 1]
As shown in Table 1 below, 30 parts by mass of bisphenol F type epoxy resin "jER 807" (Note 1) and novolak type epoxy resin "DEN.431 Epoxy Novolac Resin" (Note 3) 9 are placed in a container. By mass, 2 parts by mass of benzyl alcohol, 26.5 parts by mass of potash epoxy "Unispar PG-K10" (Note 7), 5 parts by mass of talc "Talk FC-1" (Note 8), and titanium white "TITANE". 5 parts by mass of "R-5N" (Note 9), 5 parts by mass of barium sulfate "Varico # 300W" (Note 10), 5 parts by mass of mica "Mica Powder 100 Mesh" (Note 12), and silane coupling agent " Add 11 parts by mass of "KBM403" (Note 13) and 1.5 parts by mass of the anti-drip agent "DISPARLON 6650" (Note 14), and stir at room temperature (23 ° C) using a high-speed disper until uniform. After that, it was dispersed at 56 to 60 ° C. for about 30 minutes. Then, the main ingredient was prepared by cooling to 30 ° C. or lower.
Further, as a curing agent component, 25 parts by mass of an alicyclic amine "Ancamine 2280" (Note 16) was used.
A coating composition was prepared by mixing these main agent components and curing agent components before painting.

[Examples 2 to 19 and Comparative Examples 1 to 4]
Each coating composition was prepared in the same manner as in Example 1 except that the types and blending amounts of the main agent component and the component constituting the curing agent component of Example 1 were changed as shown in Tables 1 to 3 below.
When two or more kinds of components were used as the curing agent component, the curing agent component was prepared by mixing these components at normal temperature and pressure using a high speed disper.
A description of each component shown in Tables 1 to 3 is shown in Table 4. The numerical values of each component of the main agent and the curing agent in Tables 1 to 3 indicate parts by mass.

<Dryness test>
The drying property of the obtained coating composition was tested according to JIS K 5600-3-3 (curing drying property). The coating composition is a mixture of the main agent component and the curing agent component immediately before this test. The curing and drying time of each coating composition was evaluated according to the following criteria. The results are shown in Tables 5-7.
(Evaluation criteria)
4: Curing and drying time at 10 ° C. for less than 24 hours 3: Curing and drying time at 10 ° C. for 24 hours or more and less than 36 hours 2: Curing and drying time at 10 ° C. for 36 hours or more and less than 48 hours 1: Curing and drying time at 10 ° C. Over 48 hours

[Creation of test board]
An SS400 sandblasted steel sheet (arithmetic mean roughness (Ra): 30 to 75 μm) having dimensions of 150 mm × 70 mm × 2.3 mm (thickness) was prepared. The surface of this steel sheet was coated with each of the coating compositions prepared as described above using an airless spray so that the dry film thickness was 300 μm. Then, the steel sheet with a coating film (test plate) was prepared by drying at 23 ° C. for 10 days. Each of the obtained test plates was subjected to each of the tests described later. The results are shown in Tables 5-7.
The pencil hardness of the coating film on the obtained test plate was "H" or higher. In the present invention, the pencil hardness was measured based on JIS K 5600-5-4.

<Anti-corrosion test>
The corrosion resistance of the obtained coating film was tested according to JIS K 5600-6-1 (test method for liquid resistance).
A notch 2 reaching the steel sheet from the coating film side was made at the position shown in FIG. 1 of each of the obtained test plates. The test plate 1 having the notch 2 was immersed in 3% salt water at 40 ° C. for 90 days so that the notch 2 side was facing down (in the direction shown in FIG. 1). After immersion, 11 cuts 3 are placed upward in order from the left end of the cuts 2 so that the cuts 2 are equally divided at 5 mm intervals, and the steel plate and the coating film are placed in the 10 measuring sections 4 between the cuts 3. The peeling length (length from the notch 2) was measured. The average value of the measured peeling lengths at 10 points was evaluated according to the following criteria.
(Evaluation criteria)
4: Peeling length is less than 5 mm 3: Peeling length is 5 mm or more and less than 10 mm 2: Peeling length is 10 mm or more and less than 15 mm 1: Peeling length is 15 mm or more

<Oil resistance test>
The oil resistance of the obtained coating film was tested according to JIS K 5600-6-1 (test method for liquid resistance).
Each of the obtained test plates was immersed in naphtha at room temperature for 180 days. The test plate after immersion was evaluated according to the following criteria.
(Evaluation criteria)
5: No rust was generated on the steel sheet, no blisters were generated on the coating film, and the pencil hardness of the coating film was HB or higher.
4: No rust was generated on the steel sheet, no blisters were generated on the coating film, and the pencil hardness of the coating film was B to 4B.
3: No rust was generated on the steel sheet, no blisters were generated on the coating film, and the pencil hardness of the coating film was 5B or less.
2: Slight rust was generated on the steel sheet, and blisters were generated on the coating film.
1: Rust was generated on the steel sheet, and blisters were generated on the coating film.

<Solvent resistance test>
The solvent resistance of the obtained coating film was tested according to JIS K 5600-6-1 (test method for liquid resistance).
Each of the obtained test plates was immersed in benzene or ethanol at room temperature for 180 days. The test plate after immersion was evaluated according to the same criteria as in the oil resistance test.

<Chemical resistance test>
The chemical resistance of the obtained coating film was tested according to JIS K 5600-6-1 (test method for liquid resistance).
Each of the obtained test plates was immersed in 3% sulfuric acid at room temperature for 90 days. The test plate after immersion was evaluated according to the same criteria as in the oil resistance test.

<Topcoat coating compatibility test>
The compatibility of the topcoat coating is the interlayer adhesion between the undercoat coating film and the topcoat coating film formed on the substrate from this composition, and the laminated anticorrosion coating in which the undercoat coating film and the topcoat coating film are laminated on the substrate. It can be evaluated comprehensively by the blister resistance of the substrate with a film.

The interlayer adhesion between the undercoat coating film and the topcoat coating film tends to be affected by the period from the formation of the undercoat coating film to the coating of the topcoat coating film and the resin type of the topcoat coating film. Specifically, when a cross-linking reaction type topcoat paint is applied over the undercoat coating film, the undercoat coating film peels off from the base material due to the curing shrinkage stress, and if the base material is a metal material, it causes rust. Become. Therefore, the tolerance for the period from the formation of the undercoat coating film to the coating of the topcoat coating and the tolerance for the coating film defects that may occur due to the type of resin are generally defined as the topcoat coating compatibility.

[Manufacturing method of topcoat paint]
As the topcoat paint, a topcoat paint prepared according to the following method was used.

[Epoxy resin topcoat paint]
30 parts by weight of epoxy resin "E-001-75X" (manufactured by Otake Akira Shinkagaku Co., Ltd., bisphenol A type epoxy resin xylene solution), epoxy resin "E834-85X (T)" (Otake Akira Shinkagaku) Made by Co., Ltd., Bisphenol A type epoxy resin (semi-solid at room temperature), epoxy equivalent 290-310 g / eq, non-volatile content 85%) 10 parts by weight, talc "F-2 talc" (manufactured by Fuji Talk Co., Ltd.) 20 parts by weight, heavy calcium carbonate "Calcium Carbonate Super SS" (manufactured by Maruo Calcium Co., Ltd.) 10 parts by weight, carbon black "MA-100" (manufactured by Mitsubishi Chemical Co., Ltd.) 3 parts by weight, anti-drip agent " 5 parts by weight of "Disparon A-630-20X" (manufactured by Kusumoto Kasei Co., Ltd., 20% non-volatile content), 6 parts by weight of propylene glycol monomethyl ether, 7 parts by weight of butyl cellosolve, and 9 parts by weight of methylisobutylketone are put therein. After adding the glass beads and mixing these compounding components with a paint shaker, the glass beads were removed to prepare the main component constituting the epoxy resin-based topcoat paint.

In addition, 80 parts by weight of the polyamide adduct-based curing agent "PA-23" (manufactured by Otake Meishin Kagaku Co., Ltd., active hydrogen equivalent 375 g / eq, non-volatile content 60%), tertiary amine "Ancamine K-54" (2, 4,6-Tri (dimethylaminomethyl) phenol, manufactured by Air Products Co., Ltd., 3 parts by weight, 14 parts by weight of xylene, and 3 parts by weight of n-butanol using a high-speed disper (at room temperature and under normal pressure). ) By mixing, a curing agent component constituting an epoxy resin-based topcoat was prepared.

An epoxy resin-based topcoat paint was prepared by mixing the obtained main agent component and curing agent component at a predetermined mixing ratio (main agent component: curing agent component = 9: 1) before coating.

[Acrylic resin-based topcoat paint]
20 parts by weight of acrylic resin "Paraloid B-66" (manufactured by Rohm and Hearth Japan Co., Ltd.), settling barium sulfate "precipitated barium sulfate FTB" (manufactured by Fukuoka Tarku Kogyo Co., Ltd.) 16 By weight, 20 parts by weight of titanium white "Titanium White R-930" (manufactured by Sakai Chemical Industry Co., Ltd.), 3 parts by weight of anti-sag agent "Disparon A-630-20X", 27 parts by weight of xylene, 2 parts by weight of butyl cellosolve, Add 9 parts by weight of aromatic hydrocarbon "Ipsol 100" (manufactured by Idemitsu Kosan Co., Ltd.) and 3 parts by weight of n-butanol, add glass beads to it, mix these ingredients with a paint shaker, and then mix them. An acrylic resin-based topcoat was prepared by removing the glass beads.

[Creation of test plate]
The coating composition of Examples 13 to 19 was applied to a sandblasted 70 mm × 150 mm × 1.6 mm (thickness) steel sheet using an air spray so that the dry film thickness was 200 μm, and then dried at room temperature all day and night. , Installed so that the painted surface is exposed on the outdoor exposure table (based on JIS K 5600-7-6) installed on the site of China Paint Co., Ltd. in Otake City, Hiroshima Prefecture. When an epoxy resin-based topcoat paint is applied as the topcoat paint composition, it is exposed outdoors for 1, 14, and 30 days after the paint composition is applied, and then a film applicator is applied to the painted surface of the paint composition. Each of the epoxy resin-based topcoat paints was applied so that the dry film thickness was 50 μm. When applying an acrylic resin-based topcoat paint, the paint composition is exposed outdoors for 1, 7, and 14 days after being painted, and then dried on the painted surface of the paint composition using a film applicator. Acrylic resin-based topcoat paints were applied so that the film thickness was 50 μm.

After the topcoat coating composition was applied, it was dried in an atmosphere of 23 ° C. and 50% RH for 7 days in accordance with JIS K 560-1-6 to prepare each test plate for topcoat coating compatibility evaluation.

Each test plate for evaluation of topcoat coating compatibility coated with the epoxy resin-based topcoat paint or acrylic resin-based topcoat paint is immersed in salt water (salt concentration 3%) at 40 ° C. for 30 days, and then adherent (JIS K). (Compliant with the cross-cut method specified in 5600-5-6) and blister of the coating film (according to the method A of ASTM D-714-56) were evaluated. The results obtained are shown in Table 8.

1: Test plate 2: Notch 3: Cut 4: Measuring unit

Claims (9)

A bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, an amine-based curing agent (B) having a cyclic structure, a silane coupling agent (C) having an epoxy group, and a flat pigment (D) and / or the same. Contains a pigment (E) other than the flat pigment (D),
The content of the silane coupling agent (C) is 5 to 20% by mass, and the content is 5 to 20% by mass.
The mass ratio of the bisphenol type epoxy compound (A) to the silane coupling agent (C) is 1.0: 0.1 to 0.5.
Low VOC anticorrosion paint composition. A bisphenol type epoxy compound (A) having an epoxy equivalent of 200 or less, an amine-based curing agent (B) having a cyclic structure, a silane coupling agent (C) having an epoxy group, and a flat pigment (D) and / or the same. Contains a pigment (E) other than the flat pigment (D),
It contains two or more kinds of amine-based curing agents (B) having a cyclic structure,
The content of the silane coupling agent (C) is 5 to 20% by mass.
Low VOC anticorrosion paint composition. The low VOC anticorrosion coating composition according to claim 1 or 2, wherein the silane coupling agent (C) is a silane coupling agent having one epoxy group in one molecule. The low according to any one of claims 1 to 3, wherein the amine-based curing agent (B) having a cyclic structure contains at least one selected from an alicyclic amine and a modified product of an alicyclic amine. VOC anticorrosion paint composition. The low VOC anticorrosion coating composition according to any one of claims 1 to 4, wherein the volume concentrations of the flat pigment (D) and the pigment (E) in the low VOC anticorrosion coating composition are 10 to 70%. thing. The low VOC anticorrosion coating composition according to any one of claims 1 to 5, wherein the VOC content of the low VOC anticorrosion coating composition is 200 g / L or less. An anticorrosion coating film formed from the low VOC anticorrosion coating composition according to any one of claims 1 to 6. A substrate with a coating film, which comprises the anticorrosion coating film according to claim 7 and the substrate. A method for producing a substrate with a coating film, which comprises the following steps [1] and [2].
[1] A step of applying the low VOC anticorrosion coating composition according to any one of claims 1 to 6 to a substrate [2] A step of drying the coated coating composition to form a coating film.

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