JP2009256634A - Anticorrosive paint composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anticorrosive paint composition foaming a coating film excellent in corrosion resistance of not only a general part but also of a machined part and an end face part on a painted metal plate. <P>SOLUTION: The anticorrosive paint composition comprises (A) a bisphenol epoxy resin obtained by reacting 5-50 mass% of a soft organic component with 95-50 mass% of a bisphenol epoxy resin and modified with the soft organic component, (B) a curing agent, and (C) an anticorrosive pigment. The soft organic component in the resin (A) is at least one kind among a 4-36C aliphatic polybasic acid, an acrylic acid resin with a glass transition temperature of -20°C to 50°C, and a polyester resin with a glass transition temperature of -20°C to 50°C. Preferably, the anticorrosive pigment (C) is a vanadium compound, a silicon-containing compound such as a metal silicate, or a non-chromium anticorrosive pigment mixture containing a phosphoric acid metal salt. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coating composition having excellent corrosion resistance and a coated metal plate using the same, and more specifically, in the case of a non-chromium coating composition, not only the corrosion resistance of the flat portion of the coated metal plate but also the processed part. In particular, the present invention relates to a coating composition effective for improving the corrosion resistance of an end face and a coated metal plate using the same.

  Conventionally, pre-coated metal sheets such as pre-coated steel sheets painted by coil coating, etc., building materials such as roofs, walls, shutters, garages, various household appliances, switchboards, refrigerated showcases, steel furniture, kitchen appliances, etc. Widely used as a housing related product.

  In order to manufacture these housing-related products from a pre-coated metal plate, the pre-coated steel plate is usually cut, press-molded and joined. Therefore, these housing-related products often have a metal exposed portion that is a cut surface and a crack generating portion due to press working. The exposed metal part and cracking part are more likely to have a lower corrosion resistance than other parts, so it is common to include a chromium-based rust-preventive pigment in the precoat steel base coat to improve corrosion resistance. Has been done.

  However, chromium-based rust preventive pigments contain or produce hexavalent chromium having excellent rust prevention properties, and the use of this hexavalent chromium has been restricted from the viewpoint of human health and environmental protection. ing.

  To date, many non-chromium anticorrosive pigments such as zinc phosphate, aluminum tripolyphosphate, and zinc molybdate have been put on the market, and various primers have been proposed as a combination of non-chromium pigments. ing. For example, Patent Document 1 discloses a combination of epoxy resin and phenol resin vehicle components, a combination of calcium silicate and phosphorus vanadate, and a combination of calcium carbonate, calcium silicate, aluminum phosphate, and phosphorus vanadate as antirust pigments. A paint containing a rust preventive pigment is described. Patent Document 2 describes a paint in which polyester is combined with a combination of a second magnesium phosphate and a fired product of manganese oxide / vanadium oxide or a fired product of calcium phosphate and vanadium oxide as a rust preventive pigment. Yes. However, the coating film formed from the paint described in Patent Documents 1 and 2 is inferior in corrosion resistance as compared with a paint using a chromium pigment, and in particular, the corrosion resistance in the processed part and the end face part is insufficient. . In addition, chemical resistance such as alkali resistance and acid resistance is often inferior. Further, when a large amount of rust preventive pigment is used, the water resistance is often inferior, and it has not yet been replaced by chromium-based rust preventive pigments in the production of precoated metal sheets.

  Patent Document 3 discloses that a vehicle component composed of an organic resin containing a hydroxyl group or an epoxy group and a curing agent has an oil absorption of 30 to 200 ml / 100 g and a pore volume of 0.05 to 1.2 ml / g. A coating composition containing a silica fine particle and having a glass transition temperature of 40 to 125 ° C. of a cured coating film formed from the coating is described. However, although the coating film formed from the paint described in Patent Document 3 shows considerable corrosion resistance, it is still inferior in corrosion resistance and chemical resistance compared to a paint using a chromium-based pigment. Insufficient corrosion resistance.

Japanese Patent Laid-Open No. 11-61001 JP 2000-199078 A JP 2000-129163 A

  The object of the present invention is to prevent the formation of a coating film excellent in the corrosion resistance of the processed part and the end face part as well as the general part of the coated metal plate, even in the case of a non-chromium rust-proof coating composition. A rust coating composition and a coated metal plate using the same are provided.

  Therefore, as a result of intensive studies to solve the above-mentioned conventional problems, the present inventors contain a bisphenol type epoxy resin modified with an aliphatic polybasic acid and an acrylic resin, a curing agent, and an antirust pigment. The present invention has been completed by finding that the coating composition can form not only the corrosion resistance of the flat portion but also the coating portion excellent in the corrosion resistance of the processed portion and the end surface portion of the coated metal plate.

That is, the present invention provides “1. (A) 5 to 50% by mass of a soft organic component and 95 to 50% by mass of a bisphenol epoxy resin modified with a soft organic component, (B ) A coating composition containing a curing agent and (C) a rust preventive pigment, wherein the soft organic component in the resin (A) is an aliphatic polybasic acid having 4 to 36 carbon atoms and a glass transition temperature of -20 to 20. A rust-proof coating composition, which is at least one of a 50 ° C acrylic resin and a polyester resin having a glass transition temperature of -20 to 50 ° C,
2. The anticorrosive coating composition according to item 1, wherein the resin (A) is a bisphenol type epoxy resin modified with an aliphatic polybasic acid having 4 to 36 carbon atoms and an acrylic resin having a glass transition temperature of -20 to 50 ° C. ,
3. The anticorrosive coating composition according to Item 1 or 2, wherein the aliphatic polybasic acid having 4 to 36 carbon atoms is dimer acid,
4). The rust preventive paint according to any one of the above items 1 to 3, wherein the curing agent (B) is at least one crosslinking agent among an amino resin, a phenol resin and a polyisocyanate compound which may be blocked. Composition,
5. The rust preventive paint composition according to any one of Items 1 to 4, wherein the rust preventive pigment (C) is a non-chromium rust preventive pigment,
6). The anticorrosive pigment (C) contains (1) at least one vanadium compound of vanadium pentoxide, calcium vanadate and ammonium metavanadate, (2) at least one silicon of metal silicate and silica fine particles. 6. The anticorrosive coating composition as described in 5 above, which comprises a compound and (3) a phosphate metal salt.

7). Item 1-6 above, further comprising at least one of epoxy resin having secondary or tertiary amino group, acrylic resin having secondary or tertiary amino group, and resol type phenol resin. Anticorrosive paint composition according to any one of
8). A cured coating film based on the coating composition according to any one of the above items 1 to 7 is formed on one or both surfaces of a metal plate that may be subjected to chemical conversion treatment on the surface. Painted metal plate,
9. A cured coating film based on the coating composition according to any one of the above items 1 to 7 is formed on one or both surfaces of a metal plate, the surface of which may be subjected to chemical conversion treatment. A coated metal plate having a multilayer coating film formed by forming a top coating film on at least one surface. ".

As an embodiment of the present invention,
“A. The anticorrosive coating composition according to item 6, wherein the silicon-containing compound (2) is a metal silicate of a metal selected from calcium, magnesium, and zinc,
B. The anticorrosive pigment (C) contains (1) at least one vanadium compound of vanadium pentoxide, calcium vanadate and ammonium metavanadate, (2) at least one silicon of metal silicate and silica fine particles. Containing a compound and (3) a phosphoric acid metal salt, with respect to 100 parts by mass of the total solid content of the resin (A) and the crosslinking agent (B),
3 to 50 parts by mass of the vanadium compound (1),
The amount of the silicon-containing compound (2) is 3 to 50 parts by mass, and the amount of the phosphate metal salt (3) is 3 to 50 parts by mass, and the compound (1), the compound (2) and the salt The total amount of (3) is 10 to 150 parts by mass,
C. The coating composition according to item 1, further comprising at least one pigment component of titanium dioxide pigment and extender pigment,
D. Furthermore, the coating composition of said claim | item 1 containing at least 1 sort (s) of a ultraviolet absorber and a ultraviolet stabilizer. ".

  The coating composition of the present invention is not only excellent in the corrosion resistance of the flat portion even when it does not contain a chromium-based anticorrosive pigment, but also a painted metal plate that has been difficult to achieve with non-chromium anticorrosive paints, etc. The effect that the coating film excellent in the corrosion resistance of the processed part and the end face part can be formed.

  The coated metal plate on which the cured coating film based on the coating composition of the present invention is formed has excellent corrosion resistance at the flat portion, processed portion and end face portion, and even when it does not contain a chromium-based rust preventive pigment, strontium It has corrosion resistance equivalent to or better than a coated metal plate on which a cured coating film based on a paint using a conventional chromate rust preventive pigment such as chromate is formed.

  A coated metal plate in which a cured coating film based on the coating composition of the present invention is formed, and a top coating film is formed on the cured coating film, is excellent in the corrosion resistance of the flat portion, the processed portion, and the end surface portion. When using a zinc alloy-plated steel sheet such as a zinc-plated steel sheet or an aluminum-zinc alloy-plated steel sheet as a metal plate to be coated, by coating the coating composition of the present invention, not only the flat surface part but also the end surface part, Excellent corrosion resistance can be obtained even in the processed portion.

  The coating composition of the present invention is a coating composition containing a bisphenol type epoxy resin (A) modified with a bisphenol type epoxy resin modified with a soft organic component, a crosslinking agent (B), and a rust preventive pigment (C). is there.

Bisphenol type epoxy resin modified with soft organic components (A)
The bisphenol type epoxy resin (A) modified with a soft organic component in the coating composition of the present invention (hereinafter sometimes abbreviated as “modified resin (A)”) reacts a soft organic component with a bisphenol type epoxy resin. It is resin made to let.

  The soft organic component is an organic component that has a functional group that reacts with a bisphenol-type epoxy resin and can plasticize the bisphenol-type epoxy resin, and has an aliphatic polybasic acid having 4 to 36 carbon atoms and a glass transition temperature of −20. It is at least 1 sort (s) of the acrylic resin of -50 degreeC, and the polyester resin whose glass transition temperature is -20-50 degreeC.

  The polyester resin includes both oil-free polyester resins and oil-modified polyester resins, and may be modified polyester resins such as silicon-modified polyester resins and urethane-modified polyester resins.

  The aliphatic polybasic acid having 4 to 36 carbon atoms is a saturated or unsaturated aliphatic polybasic acid having 4 to 36 carbon atoms, preferably 8 to 36, including alicyclic polybasic acids, For example, hexahydroisophthalic acid, hexahydroterephthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, methylhexahydroterephthalic acid, Δ1-tetrahydrophthalic acid, Δ2-tetrahydrophthalic acid, Δ3-tetrahydrophthalic acid, Δ4-tetrahydrophthalic acid, Δ1-tetrahydroisophthalic acid, Δ2-tetrahydroisophthalic acid, Δ3-tetrahydroisophthalic acid, Δ4-tetrahydroisophthalic acid, Δ1-tetrahydroterephthalic acid, Δ2-tetrahydroterephthalic acid, methyl Tetrahydrophthalic acid, endomethylenetetrahydrophthalic acid, methyl endomethy Cycloaliphatic acid, hexachloroendomethylenetetrahydrophthalic acid and other alicyclic dicarboxylic acids and their anhydrides; succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, dodecanedicarboxylic acid, suberic acid, pimelin Aliphatic dicarboxylic acids such as acid, maleic acid, fumaric acid, itaconic acid, brassic acid, citraconic acid, chloromaleic acid and dimer acid and their anhydrides; trivalent or higher aliphatic polybasic acids such as hexahydrotrimellitic acid Lower alkyl esters such as methyl esters and ethyl esters of these acids;

  Examples of the acrylic resin that can be used as the soft organic component in the production of the modified resin (A) include an acrylic resin having a reactive group that reacts with the epoxy group of the bisphenol type epoxy resin. The acrylic resin includes a modified acrylic resin such as a urethane-modified acrylic resin. Examples of the reactive group include a carboxyl group, an amino group, a hydroxyl group, and the like. Among the acrylic resins, an acrylic resin having a carboxyl group is preferably used.

  The acrylic resin having a carboxyl group is obtained by copolymerizing a polymerizable unsaturated monomer having a carboxyl group and other polymerizable unsaturated monomers by a known method such as a solution polymerization method, a suspension polymerization method, or a bulk polymerization method. Among them, the solution polymerization method is preferable from the viewpoint of easy control of the polymerization. The other polymerizable unsaturated monomer contains a (meth) acrylic acid ester. It is preferable that the amount of (meth) acrylic ester used is in the range of 30 to 98% by mass based on the total amount of copolymerization monomer components constituting the modified resin (A).

  Examples of the polymerizable unsaturated monomer having a carboxyl group include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid.

  Examples of the other polymerizable unsaturated monomers include 2-hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, and ε-caprolactone modified. Tetrahydrofurfuryl (meth) acrylate, ε-caprolactone modified hydroxyethyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, 2- Hydroxyl group-containing polymerizable unsaturated monomers such as hydroxy-3-butoxypropyl (meth) acrylate and monohydroxyethyl (meth) acrylate phthalate; methyl (meth) acrylate , Ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate Alkyl (meth) acrylates such as tridecyl (meth) acrylate; cycloalkyl (meth) acrylates such as cyclohexyl (meth) acrylate; benzyl (meth) acrylate, phenyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl Di (alkyl) aminoalkyl (meth) acrylates such as (meth) acrylate; glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, allyl glycidyl ester Epoxy group-containing polymerizable unsaturated monomers such as ter; vinyl aromatic compounds such as styrene, α-methylstyrene, vinyltoluene; acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, acrylamide, methacrylamide, N-methylolacrylamide, N-methylol methacrylamide, diacetone acrylamide, acryloyl morroline, N-vinyl-2-pyrrolidone, γ-acryloxypropyltrimethoxylane, γ-methacryloxypropyltrimethoxylane, vinyl chloride, propylene, ethylene, C4 ~ Examples include C20 α-olefin. These can be used alone or in combination of two or more.

  In the present specification, “(meth) acrylate” means “acrylate or methacrylate”.

The number average molecular weight of the acrylic resin is preferably in the range of 2000 to 40000, particularly 3000 to 30000 when it is synthesized by solution polymerization from the viewpoint of compatibility with the bisphenol type epoxy resin and reactivity. .
In the present specification, the average molecular weight of the resin is a value calculated based on the molecular weight of standard polystyrene from the chromatogram measured by gel permeation chromatography. As the gel permeation chromatograph, “HLC8120GPC” (manufactured by Tosoh Corporation) was used. As the columns, four columns of “TSKgel G-4000HXL”, “TSKgel G-3000HXL”, “TSKgel G-2500HXL”, “TSKgel G-2000HXL” (both manufactured by Tosoh Corporation, trade name) were used, Mobile phase: Tetrahydrofuran, measurement temperature: 40 ° C., flow rate: 1 cc / min, detector: under the conditions of RI.
The acrylic resin preferably has an acid value of 3 to 50 mgKOH / g, particularly 5 to 40 mgKOH / g, from the viewpoints of reactivity and adhesion to the bisphenol type epoxy resin. The hydroxyl value of the acrylic resin is preferably 10 to 300 mgKOH / g, particularly preferably 30 to 250 mgKOH / g, from the viewpoint of the curability and water resistance of the coating film. Furthermore, the glass transition temperature (Tg) of the acrylic resin is preferably in the range of −20 ° C. to 50 ° C., preferably in the range of −20 ° C. to 40 ° C., from the viewpoint of the balance between processability and hardness of the obtained coating film. It is. In the present specification, the glass transition temperature (Tg) of the resin is determined by scanning differential thermal analysis (DSC).

  Examples of the polyester resin that can be used as the soft organic component in the production of the modified resin (A) include polyester resins having a reactive group that reacts with the epoxy group of the bisphenol-type epoxy resin. The polyester resin includes both oil-free polyester resins and oil-modified polyester resins, and may be modified polyester resins such as silicon-modified polyester resins and urethane-modified polyester resins. Examples of the reactive group include a carboxyl group, an amino group, a hydroxyl group, and the like. As the polyester resin, among them, a polyester resin having a carboxyl group is preferably used.

  Among the polyester resins, the oil-free polyester resin can be produced using a known method such as a direct esterification method, a transesterification method, or a ring-opening polymerization method. Specific examples of the direct esterification method include a method of polycondensation of a polybasic acid and a polyhydric alcohol. As the polybasic acid, one or more dibasic acids selected from phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, adipic acid, fumaric acid, maleic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, etc .; Tribasic acid or more polybasic acid such as trimellitic anhydride, methylcyclohexylic carboxylic acid, pyromellitic anhydride, etc. is used, and benzoic acid, crotonic acid, p-tertbutylbenzoic acid, etc. are used as the acid component as required. Monobasic acids can also be used. As the polyhydric alcohol, dihydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, butanediol, neopentyl glycol, hexanediol and 1,6-hexanediol are mainly used. A trihydric or higher polyhydric alcohol such as methylolethane, trimethylolpropane and pentaerythritol can also be used in combination.

  The production of the carboxyl group-containing polyester resin can be carried out by a known method in a compounding ratio in which the acid group is excessive with respect to the hydroxyl group of the polybasic acid and the polyhydric alcohol. It can also be carried out by post-adding a polybasic acid such as trimellitic anhydride or phthalic anhydride to the hydroxyl group.

  The oil-free polyester resin can also be produced by polycondensation by transesterification between a polybasic acid lower alkyl ester and a polyhydric alcohol. Furthermore, the oil-free polyester resin can also be produced by ring-opening polymerization of lactones such as δ-valerolactone and ε-caprolactone.

  Of the polyester resins, an oil-modified polyester resin is obtained by reacting an oil fatty acid with the oil-free polyester resin. Examples of the oil fatty acid include coconut oil fatty acid, soybean oil fatty acid, linseed oil fatty acid, safflower oil. Fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, tung oil fatty acid and the like can be mentioned, and the reaction between the polyester resin and the oil fatty acid can be carried out by a known method, and the oil length is usually preferably 30% or less.

  The weight average molecular weight of the polyester resin is preferably in the range of 1000 to 30000, particularly 2000 to 20000, from the viewpoints of compatibility with the bisphenol type epoxy resin and reactivity. The acid value of the polyester resin is preferably from 3 to 100 mgKOH / g, particularly preferably from 5 to 70 mgKOH / g, from the viewpoints of reactivity and adhesion to the bisphenol-type epoxy resin. The glass transition temperature (Tg) of the polyester resin is preferably in the range of −20 ° C. to 50 ° C., preferably −20 ° C. to 40 ° C., from the viewpoint of the balance between the workability and hardness of the resulting coating film. It is.

  The bisphenol-type epoxy resin used in the production of the modified resin (A) is a bisphenol-type epoxy resin having one or more, preferably two or more epoxy groups in one molecule. For example, epichlorohydrin and bisphenol are added as necessary. A resin obtained by condensing to a high molecular weight in the presence of a catalyst such as an alkali catalyst, epichlorohydrin and bisphenol may be condensed in the presence of a catalyst such as an alkali catalyst as necessary to form a low molecular weight epoxy resin. Any of resins obtained by polyaddition reaction of a low molecular weight epoxy resin and bisphenol may be used.

  The bisphenol-type epoxy resin usually has a number average molecular weight of 350 to 5000, preferably 400 to 4000, and an epoxy group content of 0.5 to 15.4 mmol / g, preferably 0.8 to 10 mmol / g is preferred.

  Examples of the bisphenol include bis (4-hydroxyphenyl) methane [bisphenol F], 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) propane [bisphenol A], 2, 2-bis (4-hydroxyphenyl) butane [bisphenol B], bis (4-hydroxyphenyl) -1,1-isobutane, bis (4-hydroxy-tert-butyl-phenyl) -2,2-propane, bis ( 2-hydroxy-tert-butyl-phenyl) -2-hydroxy-1,3-oxy-propane, p- (4-hydroxyphenyl) phenol, oxybis (4-hydroxyphenyl), sulfonylbis (4-hydroxyphenyl), 4,4'-dihydroxybenzophenone, bis (2-hydroxynaphth Le), etc. can be mentioned methane, bisphenol A, bisphenol F are preferably used among others. The bisphenols can be used alone or as a mixture of two or more.

  As a commercial product of bisphenol type epoxy resin, for example, manufactured by Japan Epoxy Resin, jER828, 812, 815, 820, 834, 1001, 1004, 1007, 1009, 1010, 4004P, 4007P, 4210; Araldite AER6099 manufactured by Asahi Ciba; and Epomic R-309 manufactured by Mitsui Chemicals.

  The method for producing the modified resin (A) by reacting the soft organic component with the bisphenol type epoxy resin is not particularly limited. For example, when two types of soft organic components are used, a method in which two types of soft organic components and a bisphenol type epoxy resin are simultaneously reacted together, one type of soft organic component and a bisphenol type epoxy resin are reacted. Examples of the method include a method of reacting the remaining soft organic components after the reaction.

  The above reaction can be suitably performed by, for example, reacting at 100 to 150 ° C. for about 1 to 5 hours in a solvent capable of dissolving these components, if necessary, in the presence of a reaction catalyst. .

Examples of the reaction catalyst include quaternary salt catalysts such as tetraethylammonium bromide, tetrabutylammonium bromide, tetraethylammonium chloride, tetrabutylphosphonium bromide and triphenylbenzylphosphonium chloride; amines such as triethylamine and tributylamine Etc.
In the above reaction, when the reactive group of the soft organic component is a carboxyl group, the equivalent ratio of (epoxy group in the bisphenol-type epoxy resin) / (carboxyl group in the soft organic component) is 10/1 to 1 / 1, preferably within the range of 5/1 to 2/1. When the acrylic resin has a reactive group that reacts with an epoxy group other than a carboxyl group in the synthesis reaction of the modified resin (A), the ratio of each reactive group is represented by “carboxyl group in soft organic component” in the above formula. "Is preferably within the range of the formula in which" reactive group reacting with an epoxy group other than a carboxyl group "is substituted.

When the modified resin (A) is produced, the blending ratio of the soft organic component and the bisphenol type epoxy resin is within the following range based on the sum of both.
Soft organic component: 5 to 50% by mass, preferably 10 to 40% by mass,
Bisphenol type epoxy resin: 50 to 95% by mass, preferably 60 to 90% by mass.

Further, when the modified resin (A) is produced, when the aliphatic polybasic acid and the soft resin component (acrylic resin and / or polyester resin) are used in combination as the soft organic component, the modified resin (A) is produced. The blending ratio of the aliphatic polybasic acid, the soft resin component, and the bisphenol type epoxy resin is preferably within the following range on the basis of these totals.
Aliphatic polybasic acid: 1 to 30% by mass, preferably 3 to 20% by mass,
Soft resin component: 1 to 49% by mass, preferably 7 to 37% by mass,
Bisphenol type epoxy resin: 50 to 95% by mass, preferably 60 to 90% by mass.

  Further, the modified resin (A) is a sequestering agent such as benzoic acid, salicylic acid or a secondary amine compound in order to block the epoxy group when the epoxy group remains after reacting the soft organic component and the bisphenol type epoxy resin. May be reacted. Moreover, depending on the case, a blocking agent can also be made to react at the time of reaction of a soft organic component and a bisphenol type epoxy resin.

  The modified resin (A) has a soft component in the molecular structure, thereby contributing to the development of the stress relaxation ability of the crosslinked coating film, improving the workability and adhesion of the processed part, and the high rust prevention power of the resulting coating film. It is thought to contribute to the demonstration of

Curing agent (B)
The curing agent (B) reacts with the modified resin (A) to form a cured coating film, and is particularly limited as long as it can be cured by reacting with the modified resin (A) by heating or the like. Among them, amino resins, phenol resins and polyisocyanate compounds which may be blocked are suitable. These curing agents can be used alone or in combination of two or more.

  Examples of the amino resin include methylolated amino resins obtained by reacting an amino component such as melamine, urea, benzoguanamine, acetogranamamine, steroguanamine, spiroguanamine, and dicyandiamide with an aldehyde. Examples of the aldehyde used in the reaction include formaldehyde, paraformaldehyde, acetaldehyde, and benzaldehyde. Moreover, what etherified the said methylolated amino resin with suitable alcohol can also be used as an amino resin. Examples of alcohols used for etherification include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, 2-ethylbutanol, 2-ethylhexanol and the like.

  The phenol resin that can be used as the curing agent is a resin that undergoes a crosslinking reaction with the modified resin (A), and is obtained by heating a phenol component and formaldehyde in the presence of a reaction catalyst to cause a condensation reaction to introduce a methylol group. Examples thereof include a resol type phenolic resin obtained by alkyl etherifying a part or all of the methylol group of a methylolated phenolic resin with an alcohol.

  In the production of a resol-type phenol resin, a bifunctional phenol compound, a trifunctional phenol compound, a tetrafunctional or higher functional phenol compound, or the like can be used as the phenol component as a starting material.

  Examples of the phenol compound include, for example, bifunctional phenol compounds such as o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, and 2,5-xylenol. Examples of the trifunctional phenol compound include carboxylic acid, m-cresol, m-ethylphenol, 3,5-xylenol, and m-methoxyphenol. Examples of the tetrafunctional phenol compound include bisphenol A and bisphenol F. Can be mentioned. Among them, in order to improve scratch resistance, it is preferable to use a trifunctional or higher functional phenol compound, in particular, carboxylic acid and / or m-cresol. These phenol compounds may be used alone or in combination of two or more.

  Examples of formaldehydes used in the production of phenol resins include formaldehyde, paraformaldehyde, trioxane, and the like, which can be used alone or in combination of two or more.

  As the alcohol used for alkyl etherifying a part of the methylol group of the methylolated phenol resin, a monohydric alcohol having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms, can be suitably used. Suitable monohydric alcohols include methanol, ethanol, n-propanol, n-butanol, isobutanol and the like.

  A phenol resin having an average of 0.5 or more, preferably 0.6 to 3.0 alkoxymethyl groups per benzene nucleus is suitable from the viewpoint of reactivity with the modified resin (A). Yes.

  Examples of the unblocked polyisocyanate compound that can be used as the curing agent as the curing agent include aliphatic diisocyanates such as hexamethylene diisocyanate or trimethylhexamethylene diisocyanate; hydrogenated xylylene diisocyanate or Cycloaliphatic diisocyanates such as isophorone diisocyanate; organic diisocyanates themselves such as tolylene diisocyanate, xylylene diisocyanate or 4,4'-diphenylmethane diisocyanate, aromatic diisocyanates such as crude MDI, or each of these organic diisocyanates and polyvalent Adducts with alcohol, low molecular weight polyester resin or water, or as described above Cyclic polymerization of an organic diisocyanate comrades, further include isocyanate-biuret, or the like.

  The blocked polyisocyanate compound is obtained by blocking free isocyanate groups of the polyisocyanate compound with a blocking agent. Examples of the blocking agent include phenols such as phenol, cresol and xylenol; ε-caprolactam; lactones such as δ-valerolactam and γ-butyrolactam; methanol, ethanol, n-, i- or t-butyl alcohol, ethylene Alcohols such as glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and benzyl alcohol; oximes such as formamidoxime, acetaldoxime, acetoxime, methyl ethyl ketoxime, diacetyl monooxime, benzophenone oxime, cyclohexane oxime System: Active methylene such as dimethyl malonate, diethyl malonate, ethyl acetoacetate, acetylacetone It can be suitably used blocking agent, such as. By mixing the polyisocyanate compound and the blocking agent, free isocyanate groups of the polyisocyanate compound can be easily blocked.

  The blending ratio of the modified resin (A) and the curing agent (B) is 55 to 95 parts by mass of the modified resin (A) based on 100 parts by mass of the total solid content of the components (A) and (B). Furthermore, it is 60-95 mass parts, Comprising: Curing agent (B) is 5-45 mass parts, Furthermore, it is in the range of 5-40 mass parts, such as corrosion resistance, boiling-water resistance, workability, sclerosis | hardenability. From the point of view, it is preferable.

  In order to increase the curability of the coating composition of the present invention, a curing catalyst can be blended as necessary. When the curing agent (B) contains an amino resin, particularly a low molecular weight, methyl etherified or mixed etherified melamine resin of methyl ether and butyl ether, sulfonic acid compound or amine neutralization of sulfonic acid compound as a curing catalyst A thing is used suitably. Representative examples of the sulfonic acid compound include p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalenedisulfonic acid, and the like. The amine in the amine neutralized product of the sulfonic acid compound may be any of primary amine, secondary amine, and tertiary amine. Among these, the amine neutralized product of p-toluenesulfonic acid and / or the amine neutralized product of dodecylbenzenesulfonic acid is preferable from the viewpoints of the stability of the coating, the reaction promoting effect, and the physical properties of the obtained coating film. .

  When the curing agent (B) is a phenol resin, the sulfonic acid compound or an amine neutralized product of the sulfonic acid compound is preferably used as the curing catalyst.

  When the curing agent (B) is a blocked polyisocyanate compound, a curing catalyst that promotes dissociation of the blocking agent of the blocked polyisocyanate compound, which is a curing agent, is suitable. As a suitable curing catalyst, for example, octyl Tin oxide, dibutyltin di (2-ethylhexanoate), dioctyltin di (2-ethylhexanoate), dioctyltin diacetate, dibutyltin dilaurate, dibutyltin oxide, dioctyltin oxide, lead 2-ethylhexanoate And organometallic catalysts such as

  When the curing agent (B) is a combination of two or more curing agents, an effective curing catalyst can be used in combination with each curing agent.

Antirust pigment (C)
As the anti-corrosion pigment (C), any chromium-based pigment or non-chromium pigment can be used as long as it has anti-rust properties. However, it is non-chromium from the viewpoint of human health and environmental protection. It is preferable that the anticorrosive pigment is based.

  Examples of the chromium-based rust preventive pigment include strontium chromate, zinc chromate, zinc potassium chromate, barium chromate, chromium chromate, and chromium phosphate. Non-chromium rust preventive pigments include zinc phosphate, aluminum tripolyphosphate, calcium molybdate silicate, vanadium pentoxide, calcium vanadate, ammonium metavanadate, phosphorus vanadate, aluminum phosphate, calcium phosphate, dibasic magnesium phosphate, Examples thereof include calcined products of manganese oxide and vanadium oxide, calcined products of calcium phosphate and vanadium oxide, silica fine particles having an oil absorption of 30 to 200 ml / 100 g, and a pore volume of 0.05 to 1.2 ml / g. it can. These rust preventive pigments can be used alone or in combination of two or more.

  In the coating composition of the present invention, as the anticorrosive pigment (C), in particular, a combination of the following (1) vanadium compound, (2) silicon-containing compound and (3) phosphate metal salt can be suitably used.

Vanadium compound (1)
The vanadium compound (1) is at least one vanadium compound selected from vanadium pentoxide, calcium vanadate, and ammonium metavanadate. Vanadium pentoxide, calcium vanadate and ammonium metavanadate are excellent in elution of pentavalent vanadium ions into water, and the pentavalent vanadium ions released from the vanadium compound (1) react with the material metal, It works effectively to improve corrosion resistance by reacting with ions from other antirust pigment mixtures.

Silicon-containing compound (2)
The silicon-containing compound (2) is at least one of metal silicate and silica fine particles.

  The metal silicate is a salt made of silicon dioxide and a metal oxide, and may be any of orthosilicate, polysilicate, and the like. Examples of silicates include zinc silicate, aluminum silicate, aluminum orthosilicate, aluminum hydrated aluminum silicate, aluminum calcium silicate, sodium aluminum silicate, beryllium aluminum silicate, sodium silicate, calcium orthosilicate, calcium metasilicate, sodium calcium silicate, and silicic acid. Zirconium, magnesium orthosilicate, magnesium metasilicate, magnesium calcium silicate, manganese silicate, barium silicate, olivine, garnet, tortovite, cyllite, benitoite, neptunite, nymphite, turquoise, quartzite, barracite, tosen Stones, zonotorite, talc, gyoganite, aluminosilicate, borosilicate, beryllosilicate, cholite, fluorite and the like. Among them, calcium orthosilicate and calcium metasilicate are preferable as the metal silicate.

  The silica fine particles can be used without any limitation as long as they are silica fine particles. For example, silica fine powder whose surface is not treated, silica fine powder whose surface is treated with organic matter, calcium ion-exchanged silica fine particles, organic solvent-dispersible colloidal silica And so on.

  Examples of the silica fine particles whose surface is not treated or treated with an organic substance include silica fine powder having an average particle size of 0.5 to 15 μm, preferably 1 to 10 μm, and organic solvent-dispersible colloidal silica. As the fine silica powder, those having an oil absorption of 30 to 350 ml / 100 g, preferably 30 to 150 ml / 100 g can be suitably used, and as commercially available products, silicia 710, silicia 740, silicia 550, Examples include Aerosil R972 (all of which are manufactured by Fuji Silysia Chemical Co., Ltd.), Mizukacil P-73 (manufactured by Mizusawa Chemical Industry Co., Ltd.), Gasil 200DF (manufactured by Crossfield).

  Calcium ion exchanged silica is silica fine particles in which calcium ions are introduced into a fine porous silica carrier by ion exchange. Examples of commercially available calcium ion exchanged silica include SHIELDEX (Shielddex, registered trademark) C303, AC-3, AC-5 (all of which are manufactured by WR Grace & Co.). it can. Calcium ions released from calcium ion exchanged silica are involved in electrochemical action and various salt forming actions, and effectively work to improve corrosion resistance. Moreover, the silica fixed in the coating film effectively works to suppress peeling of the coating film in a corrosive atmosphere. The organic solvent-dispersible colloidal silica is also called an organosilica sol, in which silica fine particles having a particle size of about 5 to 120 nm are stably dispersed in an organic solvent such as alcohols, glycols, and ethers. Examples of commercially available products include OSCAL series (manufactured by JGC Catalysts & Chemicals Co., Ltd.) and organosol (manufactured by Nissan Chemical Co., Ltd.). Of these, calcium ion exchanged silica fine particles are preferred.

  Each metal silicate and each silica fine particle can be used as a silicon-containing compound (2) by 1 type or in combination of 2 or more types.

Phosphate metal salt (3)
The phosphoric acid metal salt (3) is at least one of a phosphoric acid metal salt, a hydrogen phosphate metal salt, and a tripolyphosphate metal salt. The metal of the phosphate metal salt is not particularly limited, and examples of suitable metals include Ca, Zn, Al, and Mg. Among these, Ca is particularly suitable.

Examples of the phosphate metal salt include calcium phosphate, calcium ammonium phosphate, calcium monohydrogen phosphate, calcium dihydrogen phosphate, calcium phosphate phosphate, zinc phosphate, aluminum phosphate, magnesium phosphate, hydrogen phosphate Examples thereof include zinc, aluminum phosphate, magnesium phosphate, aluminum hydrogen phosphate, magnesium hydrogen phosphate, magnesium ammonium phosphate, and aluminum dihydrogen triphosphate. Of these, calcium phosphate, calcium monohydrogen phosphate, and calcium dihydrogen phosphate are particularly preferred from the viewpoint of corrosion resistance. Phosphate ions released from the phosphate metal salt (3), metal ions such as Ca, Zn, Al, or Mg effectively work to improve corrosion resistance.
In the coating composition of the present invention, the amount of the anticorrosive pigment (C) is 10 to 150 parts by mass, preferably 15 to 90 parts per 100 parts by mass of the total solid content of the modified resin (A) and the curing agent (B). From the viewpoint of corrosion resistance, it is preferable that the content is part by mass, and the vanadium compound (1), the silicon-containing compound (2), and the phosphate metal salt (3) are particularly within the following ranges as the anticorrosive pigment (C). This is preferable from the viewpoint of improving the corrosion resistance.

Vanadium compound (1): 3 to 50 parts by mass, preferably 5 to 30 parts by mass,
Silicon-containing compound (2): 3 to 50 parts by mass, preferably 5 to 30 parts by mass,
Phosphate metal salt (3): 3 to 50 parts by mass, preferably 5 to 30 parts by mass.

  In the coating composition of the present invention, the corrosion resistance can be synergistically improved by combining a predetermined amount of these (1), (2) and (3) as an antirust pigment mixture.

  In the coating composition of the present invention, in addition to the modified resin (A), the curing agent (B), the rust preventive pigment (C), and a curing catalyst that is blended as necessary, it can be used in the adhesion imparting agent and coating fields. Pigments, extender pigments, UV absorbers, UV stabilizers, organic solvents; additives such as anti-settling agents, antifoaming agents, coating surface modifiers, and the like can be blended as necessary.

  Examples of the adhesion-imparting agent include epoxy resins having secondary or tertiary amino groups, and acrylic resins having secondary or tertiary amino groups. The resol type phenol resin described in the section of the curing agent (B) also has a function as an adhesion imparting agent.

  The epoxy resin having a secondary or tertiary amino group is a resin having an epoxy resin skeleton and a secondary or tertiary amino group. Examples of the epoxy resin skeleton include a bisphenol type epoxy resin skeleton and a novolac epoxy resin. Examples include skeletons.

The epoxy resin having a secondary or tertiary amino group is, for example, a secondary compound obtained by adding an amine compound to an epoxy group such as a glycidyl group in an epoxy resin such as a bisphenol type epoxy resin, a novolac epoxy resin or a urethane-modified epoxy resin. Alternatively, it can be obtained by introducing a tertiary amino group. As an epoxy resin, from the viewpoint of reactivity with an amine compound, it is usually preferable that the epoxy equivalent is about 200 to 1000, and among them, a bisphenol type epoxy resin and a novolac epoxy resin are preferable.

  When a bisphenol type epoxy resin is used, a secondary or tertiary amino group is usually present in the resin skeleton or at the end by reacting a bisphenol type epoxy resin having an epoxy equivalent of about 400 to 1000 with a primary or secondary amine compound. Can be obtained. When a novolac epoxy resin is used, a novolac epoxy resin having an epoxy equivalent of about 200 to 500 is usually used. However, when it reacts with a primary amine compound, it is easily gelled in production, and therefore a secondary or tertiary amine having a high amine concentration. When obtaining a novolak type epoxy resin having an amino group, it is usually preferable to react a secondary amine compound such as N-methylethanolamine or diethanolamine with a novolak epoxy resin.

  The acrylic resin having an amino group can be obtained, for example, by reacting an acrylic resin obtained by copolymerizing an acrylic monomer having an epoxy group such as glycidyl methacrylate with a primary or secondary amine compound. Moreover, the acrylic resin which copolymerized the acrylate or methacrylate monomer which has tertiary amino groups like N, N- dimethylamino ethyl (meth) acrylate and N, N- dimethylaminopropyl (meth) acrylate may be sufficient.

  Of the adhesion-imparting agent (D), an epoxy resin system is preferable from the viewpoint of the toughness of the coating film required for scratch resistance, and an acrylic resin system is preferable from the viewpoint of water resistance and chemical resistance. It is suitable, and two or more kinds of adhesion imparting resins can be used in combination as required.

  Examples of the colored pigment include organic colored pigments such as cyanine blue, cyanine green, organic red pigments such as azo and quinacridone; and inorganic colored pigments such as titanium white, titanium yellow, bengara, carbon black, and various fired pigments. Among them, titanium white can be preferably used.

  Examples of the extender pigment include talc, clay, mica, alumina, calcium carbonate, barium sulfate and the like.

  Examples of the ultraviolet absorber include 2- (2-hydroxy-3,5-di-t-amylphenyl) -2H-benzotriazole, isooctyl-3- (3- (2H-benzotriazol-2-yl)- 5-t-butyl-4-hydroxyphenylpropionate, 2- [2-hydroxy-3,5-di (1,1-dimethylbenzidine) phenyl] -2H-benzotriazole, 2- [2-hydroxy-3- Dimethylbenzyl-5- (1,1,3,3-tetramethylbutyl) phenyl] -2H-benzotriazole, methyl-3- [3-t-butyl-5- (2H-benzotriazol-2-yl)- Benzotriazole derivatives such as condensates with 4-hydroxyphenyl] propionate / polyethylene glycol 300; 2- [4- (2-hydroxy -3-dodecyloxypropyl) oxy] -2-triazine derivatives such as 2-hydroxyphenyl-4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine; ethanediamide-N- (2-ethoxy Succinic acid anilide such as phenyl) -N ′-(2-ethylphenyl)-(oxalic amide), ethanediamide-N- (2-ethoxyphenyl) -N ′-(4-isododecylphenyl)-(oxalic amide) System derivatives and the like.

  Examples of the UV stabilizer include hindered amine compounds, hindered phenol compounds; CHIMASORB 944, TINUVIN 144, TINUVIN 292, TINUVIN 770, IRGANOX 1010, IRGANOX 1098 (all of these products are products of Ciba Specialty Chemicals) Product)).

  By blending UV absorbers and UV stabilizers in the paint, it is possible to suppress the deterioration of the coating surface due to light. Even when this paint is used as a primer, it passes through the upper coating film and becomes a primer. Since the primer surface can be prevented from deteriorating due to light reaching the surface of the paint film, it can prevent delamination between the primer paint film and the upper paint film due to the deterioration of the primer paint film surface, providing excellent interlayer adhesion and corrosion resistance. Can be maintained.

  The organic solvent that can be blended in the coating composition of the present invention is blended as necessary for improving the paintability of the composition of the present invention and dissolves the modified resin (A) and the curing agent (B). Specifically, for example, hydrocarbon solvents such as toluene, xylene, high boiling petroleum hydrocarbons, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, isophorone, ethyl acetate, acetic acid Ester solvents such as butyl, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, alcohol solvents such as methanol, ethanol, isopropanol, butanol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol Etc. can be mentioned ether alcohol solvents such as mono-butyl ether, which may be used alone or in combination of two or more.

  In the coating composition of the present invention, the glass transition temperature of the cured coating film obtained from the composition of the present invention is 40 to 115 ° C, preferably 50 to 105 ° C, such as the corrosion resistance, acid resistance and workability of the coating film. To preferred. The glass transition temperature of the coating film is tan δ by temperature dispersion measurement at a frequency of 110 Hz using a DINAMIC VISCOELASTOMETER MODEL VIBRON (dynamic viscoelastometer model vibron) DDV-IIEA type (manufactured by Toyo Baldwin, automatic dynamic viscoelasticity measuring machine). It is the maximum temperature obtained from the change in.

  The coating film formed by coating the coating composition of the present invention on a metal plate exhibits excellent corrosion resistance. The reason for this is that the resin component in the coating composition of the present invention has a stress relaxation capability. This is considered to be due to the ability to form a coating film that is excellent and has an excellent balance between elastic modulus and elongation.

Painted metal plate The coating composition of the present invention can obtain a painted metal plate by coating and curing on a metal plate. As the metal plate to be coated, cold rolled steel plate, hot dip galvanized steel plate, electrogalvanized steel plate, iron-zinc alloy plated steel plate (galvanyl steel plate), aluminum-zinc alloy plated steel plate (containing about 55% aluminum in the alloy) Metal plate such as “galvanium steel plate”, “galfan” containing about 5% aluminum in the alloy), nickel-zinc alloy plated steel plate, stainless steel plate, aluminum plate, copper plate, copper plated steel plate, tin plated steel plate, etc. The surface of the metal plate may be subjected to chemical conversion treatment. Examples of the chemical conversion treatment include phosphate treatment such as zinc phosphate treatment and iron phosphate treatment, composite oxide film treatment, chromium phosphate treatment, and chromate treatment.

  The composition of the present invention can be coated on the metal plate by a known method such as a roll coating method, a curtain flow coating method, a spray method, a brush coating method, or a dipping method. Although the cured film thickness of the coating film obtained from this invention composition is not specifically limited, Usually, 2-10 micrometers, Preferably it is used in the range of 3-6 micrometers. Curing of the coating film may be appropriately set according to the type of resin used, etc., and when the material coated by the coil coating method is continuously baked, the material reached maximum temperature is usually 160 to 250 ° C. It is preferably baked for 15 to 60 seconds under the condition of 180 to 230 ° C. In the case of baking in a batch system, it can be carried out by baking at 80 to 200 ° C. for 10 to 30 minutes. In addition, in the case of a combination that does not particularly require heating for the crosslinking reaction in the coating film formation process, such as when a non-blocked polyisocyanate is used as the crosslinking agent (B), it is dried at room temperature according to a conventional method. It can also be cured.

  The coated metal plate of the present invention has a coating film formed of the above-described coating composition of the present invention on a metal plate which may be subjected to chemical conversion treatment, and the coated metal plate formed with the coating film of the present coating composition The coating itself can be used, but a top coating film can also be provided on this coating film. The film thickness of the top coat film is usually 8 to 30 μm, preferably 10 to 25 μm.

  Examples of the top coating material for forming the top coating film include various top coating materials such as polyester resin-based, alkyd resin-based, silicon-modified polyester resin-based, silicon-modified acrylic resin-based, and fluorine resin-based materials that are known for pre-coated steel sheets. be able to. When workability is particularly important, a coated steel sheet having particularly excellent workability can be obtained by using a polyester-based top coat for advanced processing. The coated metal plate of this invention can show the coating-film performance excellent in corrosion resistance.

  When using a galvanized steel plate or an aluminum-zinc alloy plated steel plate as the metal plate to be coated, the corrosion resistance of the flat surface has been considerably improved. Although the corrosion resistance was insufficient, by applying the coating composition of the present invention, excellent corrosion resistance can be obtained also in the end face part and the processed part.

  Moreover, the coating film by this invention coating composition may be provided in both surfaces of to-be-coated article, and the said top coating film is further formed on the coating film by this invention coating composition as needed. May be. By using a non-chromium rust preventive pigment that does not contain a chromium rust preventive pigment as the rust preventive pigment in the present paint composition, it is possible to obtain a coated metal plate that is advantageous in terms of environmental hygiene and excellent in corrosion resistance. it can.

  Hereinafter, the present invention will be described more specifically with reference to production examples and examples. The present invention is not limited to the following examples. Hereinafter, “parts” and “%” are based on mass.

Synthesis Example 1 Production of Soft Acrylic Resin AC1 Solution
65.0 parts of Swazol 1000 (manufactured by Maruzen Petrochemical Co., Ltd., high-boiling aromatic petroleum solvent) was added to a flask equipped with a stirrer, condenser, thermometer, nitrogen inlet tube and dropping device, and reacted while stirring. The temperature in the container was raised to 110 ° C., and a mixture of raw materials such as monomers shown below was added dropwise over 3 hours while maintaining the temperature at 110 ° C.
Styrene 18.4 parts Methyl methacrylate 31.2 parts n-butyl acrylate 37.5 parts 2-hydroxyethyl acrylate 11.0 parts acrylic acid 1.9 parts 2,2′-azobisisobutyronitrile 7 parts After the completion of dropping, 0.5 parts of 2,2′-azobisisobutyronitrile was further added, and the reaction was further continued for 2 hours at the same temperature. Then, 35.0 parts of cyclohexanone was added, and the solid content was 50%. A soft acrylic resin AC1 solution was obtained. The soft acrylic resin AC1 had an acid value of 15 mgKOH / g, a hydroxyl value of 53 mgKOH / g, a glass transition temperature of 5 ° C., and a number average molecular weight of about 10,000.

Synthesis Examples 2 to 10
The synthesis was carried out in the same manner as in Synthesis Example 1 except that the monomer composition was as shown in Table 1, and each soft acrylic resin AC2 to AC10 solution having a solid content of 50% was obtained. Synthesis Example 11 Synthesis of Soft Polyester Resin PE1 Solution Stirring The following raw material mixture was put into a reactor equipped with an apparatus, a heating apparatus, a thermometer, a separation apparatus, and a distillate storage tank, and heating was started.
Neopentyl glycol 105 parts 1,6-Hexanediol 354 parts Hexahydrophthalic anhydride 564 parts Adipic acid 123 parts After stirring, when stirring is possible, stirring is started and the temperature is raised to 240 ° C while draining condensed water The reaction was continued at the same temperature. When the outflow of water stopped after about 1.5 hours, 40 parts of xylene was added to promote the reaction, dehydration condensation was continued, and the reaction was continued until the acid value reached 52. Next, the mixture was cooled, and 417 parts of cyclohexanone was added for dilution to obtain a polyester resin PE1 solution having a solid content of 70%. The resulting resin had a number average molecular weight of 2100.

Synthesis Examples 12-15
The synthesis was carried out in the same manner as in Synthesis Example 11 except that the composition shown in Table 1 was obtained, and each soft polyester resin PE2 to PE5 solution having a solid content of 70% was obtained. The compounding amounts in Table 1 are displayed in parts by mass.

Production Example 1 Production of Modified Bisphenol Type Epoxy Resin ME1 Solution In a flask equipped with a stirrer, condenser and thermometer, 60 parts of cyclohexanone and 90 parts of jER1007 (Japan Epoxy Resin bisphenol A type epoxy resin, epoxy equivalent of about 1800) are blended. And heated to 130 ° C. to dissolve the epoxy resin. After confirming that the epoxy resin was completely dissolved, an epoxy resin solution having a solid content of 60% was obtained. To 150 parts of the obtained epoxy resin solution having a solid content of 60%, 20 parts of the 50% soft acrylic resin AC1 solution obtained in Synthesis Example 1 (10 parts by solid content) and 0.5 part of tetraethylammonium bromide are added, and the temperature is increased. It was kept at 130 ° C. and reacted for 3 to 4 hours. Confirm that the resin acid value is 1 or less, and add mixed solvent 1 [cyclohexanone / swazol 1000 (manufactured by Maruzen Petrochemical Co., Ltd., high boiling aromatic petroleum solvent) = 1/2 (mass ratio)] A resin solution ME1 having a solid content of 40% was obtained.

Production Examples 2 to 37 (Production Examples 29 to 37 are for comparative examples)
Except for the formulation shown in Table 2, the same operation as in Production Example 1 was performed to obtain a modified bisphenol-type epoxy resin ME2-37 solution having a solid content of 40%. The compounding amount in Table 2 is a display by solid content. In addition, also in the manufacture examples 2-37, melt | dissolution of an epoxy resin is performed like the manufacture example 1 except performing by the kind and quantity of the epoxy resin shown in Table 2, and the solid content of an epoxy resin solution will be 60%. Went so.

  Polyester resin PE6 used in Production Examples 34 and 37 means ER-8101 (polyester resin manufactured by Unitika Ltd., acid value of about 62, glass transition temperature of about 64 ° C., number average molecular weight of about 2000).

The notes in Table 2 have the following meanings:
(Note 1) jER1007: manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin, epoxy equivalent of about 1800.
(Note 2) jER4007P: Japan Epoxy Resin Co., Ltd., bisphenol F type epoxy resin, epoxy equivalent of about 2270.
(Note 3) jER1004: manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin, epoxy equivalent of about 925.
(Note 4) jER4004P: bisphenol F type epoxy resin manufactured by Japan Epoxy Resin Co., Ltd. Epoxy equivalent about 880
(Note 5) jER1001: manufactured by Japan Epoxy Resin, bisphenol A type epoxy resin, epoxy equivalent of about 475.

Production Example 38 Production of Resol Type Phenolic Resin D1 Solution In a reaction vessel, 100 parts of p-cresol, 178 parts of 37% aqueous formaldehyde solution and 1 part of sodium hydroxide were blended and reacted at 60 ° C. for 3 hours. Dehydrated at 50 ° C. for 1 hour. Then, 100 parts of n-butanol and 3 parts of phosphoric acid were added and reacted at 110 to 120 ° C. for 2 hours. After completion of the reaction, the resulting solution was filtered to remove sodium phosphate, which was obtained, thereby obtaining a resol type phenol resin D1 solution having a solid content of about 50%. The obtained resin had a number average molecular weight of 880, an average number of methylol groups per benzene nucleus of 0.4, and an average number of alkoxymethyl groups of 1.0.

Production Example 39 Production of resol type phenolic resin D2 solution In a reaction vessel, 100 parts of carboxylic acid, 178 parts of 37% aqueous formaldehyde solution and 1 part of sodium hydroxide were blended and reacted at 60 ° C. for 3 hours. And dehydrated for 1 hour. Then, 100 parts of n-butanol and 3 parts of phosphoric acid were added and reacted at 110 to 120 ° C. for 2 hours. After completion of the reaction, the resulting solution was filtered to remove sodium phosphate produced to obtain a resol type phenolic resin D2 solution having a solid content of about 50%. The obtained resin had a number average molecular weight of 880, an average number of methylol groups per benzene nucleus of 0.4, and an average number of alkoxymethyl groups of 1.0.

Production Example 40 Production of Amino Group-Containing Epoxy Resin D3 In a reaction vessel equipped with a stirrer and a heating / temperature controller, 65 parts by weight of methoxybutyl acetate solvent, jER1002 (bisphenol A type epoxy resin manufactured by Japan Epoxy Resin, epoxy equivalent of 650) ) 35 parts and 1.09 parts of 2-aminoethanol were charged, heated to 90 ° C. in a nitrogen atmosphere, and reacted for 2 hours with stirring. Next, 1.89 parts of diethanolamine was added, and the reaction was further performed at 90 ° C. for 1 hour, followed by dilution with a methoxybutyl acetate solvent to obtain an amino group-containing epoxy resin D3 solution having a solid content of 35%.

Production Example 41 Production of amino group-containing epoxy resin D4 In a reaction vessel equipped with a stirrer and a heating / temperature control device, 65 parts of methoxybutyl acetate solvent, Araldite ECN1299 (Cresol novolak epoxy resin, Asahi Kasei Chemicals, epoxy equivalent 225) 35 Part, 5.83 parts of N-methylethanolamine, heated to 80 ° C. in a nitrogen atmosphere, reacted for 2 hours with stirring, diluted with methoxybutyl acetate solvent, amino acid with a solid content of 35% A group-containing epoxy resin D4 solution was obtained.

Production Example 42 Production of amino group-containing acrylic resin D5 In a reaction vessel equipped with a stirrer and a heating / temperature control device, 40 parts of propylene glycol monomethyl ether was charged and heated to 90 ° C. in a nitrogen atmosphere. Then, a premixed mixed solution of 50 parts of styrene, 50 parts of glycidyl methacrylate, 1 part of 2,2′-azobisisobutyronitrile and 10 parts of propylene glycol monomethyl ether was kept in a reaction vessel maintained at 90 ° C. Over 3 hours. After completion of the dropping, 0.2 part of AIBN was further added and reacted at the same temperature for 30 minutes, and then 0.2 part of 2,2′-azobisisobutyronitrile was further added and reacted for 3 hours. . Thereafter, 50 parts by weight of propylene glycol monomethyl ether was added to obtain an acrylic resin solution having a solid content of 50%.
In a separate reaction vessel equipped with a stirrer and a heating / temperature control device, 200 parts of the acrylic resin solution having a solid content of 50% obtained above was charged and heated to 85 ° C. while stirring. Next, a mixed solution of 26.4 parts of N-methylethanolamine and 53.6 parts of propylene glycol monomethyl ether mixed in advance is dropped into the reaction vessel over 30 minutes, and further reacted at the same temperature for 5 hours. Then, 36 parts of propylene glycol monomethyl ether was added to obtain an amino group-containing acrylic resin D5 solution having a solid content of 40%.

Production Example 43 Production of amino group-containing acrylic resin D6 A reaction vessel equipped with a stirrer and a heating / temperature control device was charged with 40 parts of propylene glycol monomethyl ether and heated to 90 ° C. in a nitrogen atmosphere. Next, a premixed mixed solution of 50 parts of styrene, 30 parts of ethyl acrylate, 20 parts of N, N-dimethylaminoethyl acrylate, 1 part of 2,2′-azobisisobutyronitrile and 10 parts of propylene glycol monomethyl ether Was dropped into a reaction vessel maintained at 90 ° C. over 3 hours. After completion of the dropwise addition, 0.2 part of 2,2′-azobisisobutyronitrile was further added and reacted at the same temperature for 30 minutes. Then, 2,2′-azobisisobutyronitrile was further added to 0.2 parts. The reaction was carried out for 3 hours. After completion of the reaction, 100 parts of propylene glycol monomethyl ether was added to obtain an amino group-containing acrylic resin D6 solution having a solid content of 40%.

Production Example 44 Production of paint for back side
80 parts of jER1009F (Japan Epoxy Resin, bisphenol A type epoxy resin, epoxy equivalent of about 2000) is mixed solvent 2 [cyclohexanone / ethylene glycol monobutyl ether / swazol 1500 (manufactured by Maruzen Petrochemical Co., Ltd., high boiling aromatic hydrocarbon) System solvent) = 3/1/1 (mass ratio)] in 200 parts of epoxy resin solution dissolved in 120 parts, titanium white 40 parts, barita 40 parts and mixed solvent 3 [swazol 1500 / cyclohexanone = 1/1 (mass ratio) )] Was mixed in an appropriate amount, and the pigment was dispersed until the tube (particle diameter of the coarse pigment particles) became 20 microns or less. Next, 26.7 parts (20 parts by solid content) of Desmodur BL-3175 (manufactured by Sumika Bayer Urethane Co., Ltd., HDI isocyanurate type polyisocyanate compound solution blocked with methyl ethyl ketoxime, solid content of about 75%) was added to this dispersion. ), Takenate TK-1 (manufactured by Takeda Pharmaceutical Co., Ltd., organotin blocking agent dissociation catalyst, solid content of about 10%) is added and mixed uniformly. Further, the mixed solvent 3 is added and the viscosity is about 80 seconds (Ford Cup # 4/25 ° C.) to obtain a back coating material.

Example 1 Production of Rust-Preventing Paint Composition
To 200 parts of modified bisphenol-type epoxy resin ME1 solution modified with the soft organic component obtained in Production Example 1, 20 parts of vanadium pentoxide, 20 parts of calcium metasilicate, 20 parts of calcium phosphate, titanium white An appropriate amount of 20 parts, 20 parts of barita, and mixed solvent 3 [Swazole 1500 / cyclohexanone = 1/1 (mass ratio)] was mixed, and the pigment dispersion was performed until the tube (particle diameter of the coarse pigment particles) became 20 microns or less. went. Then, 26.7 parts (20 parts by solid content) of Desmodur BL-3175 (manufactured by Sumika Bayer Urethane Co., Ltd., HDI isocyanurate type polyisocyanate compound solution blocked with methyl ethyl ketoxime, about 75% solid content). ), Takenate TK-1 (manufactured by Takeda Pharmaceutical Co., Ltd., organotin blocking agent dissociation catalyst, solid content of about 10%), and uniformly mixed, and further mixed solvent 2 and viscosity of about 80 seconds (Ford Cup # 4/25 ° C.) to obtain a rust preventive coating composition.

Examples 2-56 and Comparative Examples 1-11
In Example 1, except that the modified bisphenol type epoxy resin, the curing agent, the adhesion-imparting agent, the rust preventive pigment, and other pigments to be used are as shown in Table 3 below, each rust preventive was performed in the same manner as in Example 1. A coating composition was obtained. The amounts of the modified bisphenol type epoxy resin, the curing agent, and the pigment component in Table 3 are all expressed by solid mass. However, in Examples 26 to 30, instead of 2 parts of Takenate TK-1, 1 part of Neicure 5225 (manufactured by King Industries Ltd., an amine neutralized solution of dodecylbenzenesulfonic acid) is blended. To do. In Table 3, when resol type phenol resin is blended, when other curing agent is blended, resol type phenol resin is described in the column of adhesion imparting agent, and when no other curing agent is blended, resole type phenol The resin is listed in the column of curing agent.

In Table 3 above, (Note) in the table has the following meanings.
(Note 6) Cymel 303: Nippon Cytec Industries Co., Ltd., trade name, methyl etherified melamine resin.
(Note 7) Ca ion exchange silica: R. Grace & Co. SHIELDEX (Shielddex, registered trademark) C303 manufactured by the company.
(Note 8) Uban 20SE60: manufactured by Mitsui Chemicals, Inc., trade name, butyl etherified melamine resin, non-volatile content 60%.

Preparation of test coating plate Each rust preventive coating composition and top coating obtained in Examples 1 to 56 and Comparative Examples 1 to 11 were used, and each material was coated and baked according to the following coating specifications. A painted plate was obtained.

Paint specifications:
Chemically treated galvalume steel sheet (thickness 0.35 mm, aluminum-zinc alloy plated steel sheet, containing about 55% aluminum in alloy, alloy plating basis weight 150 g / m ² , indicated as “GL steel sheet” in Table 2 The back coating obtained in Production Example 44 was applied with a bar coater to a dry film thickness of 8 μm, and baked for 30 seconds so that the maximum material temperature reached 180 ° C. Formed. On the steel plate surface opposite to the back surface coating film of the coated plate on which this back surface coating film was formed, each rust preventive coating composition obtained in each of the above examples was coated with a bar coater so as to have a dry film thickness of 5 μm. Each primer coating was formed by baking for 40 seconds so that the maximum temperature reached 220 ° C. After cooling, KP color 1580B40 (trade name, polyester-based top coating, blue, glass transition temperature of cured coating about 70 ° C.) is applied to these primer coatings with a bar coater. The coating was applied to a thickness of about 15 μm, and baked for 40 seconds so that the maximum material temperature reached 220 ° C., to obtain a test plate for each test.

Coating Film Performance Test A coating film performance test was performed on each of the test coating plates obtained in Examples 1 to 56 and Comparative Examples 1 to 11 according to the following test method. The test results are shown in Table 4 below.

Test method Workability: 4T bending process (surface side of the coated plate on the outer side) so that the length of the bent portion is 6 cm on each test coated plate cut to a size of 6 cm x 12 cm at room temperature of 20 ° C Then, four plates having the same thickness as the painted plate were sandwiched inside, and the painted plate was bent 180 degrees with a vise). The crack resistance of the coating film in the bent portion and the adhesion of the coating portion in the bent portion were comprehensively evaluated according to the following criteria. The adhesiveness of the coating film in the bent portion was evaluated by the degree of peeling of the coated film in the bent portion when a cellophane adhesive tape was applied to the bent portion and the tape was peeled off instantaneously.
A: Neither cracking of the coating film nor peeling of the coating film is observed in the processed part.
◯: Slight occurrence of both cracking and peeling of the coating film and peeling of the coating film are recognized in the processed part,
(Triangle | delta): Both the generation | occurrence | production of the crack of a coating film and peeling of a coating film are recognized considerably in a process part,
X: Remarkable occurrence of cracking of the coating film and / or peeling of the coating film in the processed part.

  Boiling water resistance: After each test coating plate cut to a size of 5 cm × 10 cm is immersed in boiling water at about 100 ° C. for 5 hours, it is pulled up to evaluate the appearance of the coating film on the surface side, and a cross-cut tape adhesion test And evaluated. The cross-cut tape adhesion test is based on JIS K-5400 8.5.2 (1990) cross-cut tape method, the gap interval of the cuts is 1 mm, 100 cross-cuts are made, and cellophane adhesive tape is adhered to the surface. And the number of grids remaining on the coated surface after abrupt peeling was examined.

A: There is no abnormality such as blistering or whitening in the coating film, and there are 100 remaining grids,
○: There are no abnormalities such as blistering and whitening in the coating film, and a residual grid number of 91 to 99,
Δ: Slightly abnormalities such as blistering or whitening are observed in the coating film, and the residual grid number is 91 to 99, or there is no abnormality such as blistering or whitening in the coating film, but the residual grid number is 71 to 99. 90 pieces
X: Generation | occurrence | production of the swelling of a coating film is recognized fairly or remarkably, or the number of remaining grids is 70 or less.

  Alkali resistance: The back surface and the cut surface of each test paint plate cut to a size of 5 cm × 10 cm were sealed with a rust-proof paint, and a cross cut reaching the substrate was put in the center of the front side of the paint plate. This coated plate was immersed in a 5% aqueous sodium hydroxide solution at 30 ° C. for 48 hours, then taken out, washed, and evaluated for the appearance of the coating on the surface side of the coated plate dried at room temperature. Was peeled off, and the peel width (one side) from the cut portion in the coating film after peeling off was evaluated.

A: There is no occurrence of blisters, and the tape peeling width from the cut part is 1.5 mm or less.
○: There is no occurrence of blisters, and the tape peeling width from the cut part exceeds 1.5 mm, 3 mm or less,
Δ: Slight occurrence of swelling is observed, but tape peeling width from the cut portion is 3 mm or less, or occurrence of swelling is not recognized, but the tape peeling width from the cut portion exceeds 3 mm,
X: Generation | occurrence | production of a swelling is recognized and the tape peeling width from a cut part exceeds 3 mm.

  Scratch resistance: At a room temperature of 20 ° C., the edge of the 10-yen coin is pressed at an angle of about 45 degrees against the coating surface on the surface side of each test coating plate, and the 10-yen copper coin is 10 mm while being pressed with a load of 3 kg. The film was evaluated according to the following criteria from the degree of scratching when the coating surface was scratched by pulling about 30 mm at a rate of / sec and the difficulty of peeling off the coating film from the substrate.

A: No metal substrate is seen on the scratched part.
○: A slight metal base is seen on the scratched part.
△: A considerable amount of metal base is seen in the scratched part,
X: A coating film is hardly left on the scratched part, and the metal base is clearly seen.

  Combined cycle corrosion test (CCT test): according to JASO M609-91 (automobile material corrosion test 1991). For each test, cut to a size of 6 cm x 12 cm so that the burrs at the edge of the long side of each test coating plate face the front side on the right side toward the front side and the back side on the left side. Insert a cross cut with a narrow angle of 30 degrees and a line width of 0.5 mm into the center of the surface side of the paint board using the back of the cutter knife, and seal the top edge of the paint board with anticorrosive paint. Is provided with a 4T bending portion (processing to bend with the surface side of the coated plate facing outward, sandwiching four plates of the same thickness as the painted plate inside, and bending the painted plate 180 degrees in a vise) With respect to the coated plate, 150 cycles (with 5% saline spraying at 35 ° C. for 2 hours) — (drying at 60 ° C. for 4 hours relative humidity 95%) — (wetting at 50 ° C. for 2 hours relative humidity 95%) as one cycle. The test was conducted for a total of 1200 hours. The state of the 4T bending process part, crosscut part, and edge part of the coated board after this test was evaluated.

(4T process part) The total length of the rust part in a 4T process part was evaluated.
A: No occurrence of rust,
○: White rust is observed, but less than 20 mm,
Δ: White rust is 20 mm or more and less than 40 mm,
X: Generation | occurrence | production of white rust 40 mm or more or red rust is recognized.

(Cross cut part) Corrosion state of the cross cut part, by the average value of the white rust occurrence length ratio in the bare metal exposed part of 0.5mm cut width, and the left and right swelling width (sum of both sides) of the cut part, Evaluation was made according to the following criteria.
A: White rust generation length ratio in exposed metal portion is less than 50% and swelling width is less than 3 mm,
○: White rust generation length ratio in the bare metal exposed portion is 50% or more and less than 3 mm in width, or white rust occurrence length ratio in the bare metal exposed portion is less than 50% and in the bulge width is 3 mm or more and less than 5 mm,
Δ: White rust generation length ratio in exposed metal portion is 50% or more and swelling width is 5 mm or more and less than 10 mm,
X: The white rust generation length ratio in the bare metal exposed part is 50% or more and the swelling width is 10 mm or more.

(Edge part) The average value of the edge creep widths of the left and right long sides of the coated plate was determined and evaluated according to the following criteria.
A: Less than 5 mm
○: 5 mm or more and less than 10 mm,
Δ: 10 mm or more and less than 20 mm,
X: 20 mm or more.

  Weather-resistant salt spray test: Based on A method of accelerated weathering (xenon lamp method) test for long-term durability of coating film specified in JIS K 5600 7.7 on a test coating plate cut to a size of 5 cm × 10 cm, Irradiation was continued for 500 hours with a xenon weatherometer under repeated cycle conditions (wet 18 minutes-dry 102 minutes). Next, the back surface and the cut surface were sealed with a rust preventive paint, and a cross cut reaching the substrate was put in the center of the surface of the painted plate. About this coating board, after performing the salt spray test (JIS Z-2371) for 500 hours, the external appearance of the plane part was evaluated by the following reference | standard.

A: The swelling / rust progression width from the cut part is 3 mm or less on average across the cut, and no other abnormalities are observed.
○: The bulge / rust progression width from the cut part exceeds 3 mm and is 5 mm or less, and no abnormality is observed in the flat part and others, or slight blistering is observed in the flat part, but from the cut part The swelling / rust progression width is 3 mm or less.
Δ: The swelling / rust progression width from the cut part exceeds 3 mm and is 5 mm or less, and slight swelling is observed in the flat part.
X: The swelling / rust progression width from the cut portion exceeds 5 mm, or significant swelling is observed in the flat portion.

Claims (9)

(A) A bisphenol type epoxy resin modified with a soft organic component obtained by reacting 5 to 50% by mass of a soft organic component and 95 to 50% by mass of a bisphenol type epoxy resin, (B) a curing agent and (C) an anti-corrosion agent A coating composition containing a rust pigment, wherein the soft organic component in the resin (A) is an aliphatic polybasic acid having 4 to 36 carbon atoms, an acrylic resin having a glass transition temperature of -20 to 50 ° C, and a glass transition A rust preventive coating composition, which is at least one of polyester resins having a temperature of -20 to 50 ° C. The rust preventive coating composition according to claim 1, wherein the resin (A) is a bisphenol type epoxy resin modified with an aliphatic polybasic acid having 4 to 36 carbon atoms and an acrylic resin having a glass transition temperature of -20 to 50 ° C. . The rust preventive coating composition according to claim 1 or 2, wherein the aliphatic polybasic acid having 4 to 36 carbon atoms is dimer acid. The rust preventive paint according to any one of claims 1 to 3, wherein the curing agent (B) is at least one cross-linking agent among an amino resin, a phenol resin and a polyisocyanate compound which may be blocked. Composition. The rust preventive paint composition according to any one of claims 1 to 4, wherein the rust preventive pigment (C) is a non-chromium rust preventive pigment. The rust preventive pigment (C) contains (1) at least one vanadium compound of vanadium pentoxide, calcium vanadate and ammonium metavanadate, and (2) at least one silicon of metal silicate and silica fine particles. 6. The rust preventive coating composition according to claim 5, comprising a compound and (3) a phosphate metal salt. Furthermore, it contains at least one of epoxy resins having secondary or tertiary amino groups, acrylic resins having secondary or tertiary amino groups, and resol type phenol resins. The antirust coating composition as described in any one of these. A cured coating film based on the coating composition according to any one of claims 1 to 7 is formed on one surface or both surfaces of a metal plate that may be subjected to chemical conversion treatment on the surface. Painted metal plate. A cured coating film based on the coating composition according to any one of claims 1 to 7 is formed on one surface or both surfaces of a metal plate, the surface of which may be subjected to chemical conversion treatment. A coated metal sheet having a multilayer coating film in which a top coating film is formed on at least one surface.