TWI458793B - Excellent corrosion-resistant coating composition - Google Patents

Description

Coating composition excellent in corrosion resistance

The present invention relates to a non-chromium coating composition excellent in corrosion resistance and a coated metal sheet using the same, and more particularly to a corrosion resistance which is not only effective for improving the flat portion of the coated metal sheet, but also A coating composition that effectively enhances the corrosion resistance of the processed portion or the end portion (even if the coating film begins to deteriorate due to photolysis or hydrolysis in an outdoor environment) and a coated metal sheet using the same.

Conventionally, precoated metal sheets such as precoated steel sheets coated by coil coating treatment and the like are widely used as building materials for roofs, walls, sun visors, garages, and the like, various home electric appliances, and switchboards. Residential related products such as frozen display cases, steel furniture and kitchen appliances.

When such a house-related product is produced from the precoated metal sheet, the precoated steel sheet is usually cut and pressed and joined. However, most of these residential related products have a metal exposed portion of the cut surface or a cracked portion produced by press processing. The metal exposed portion or the cracked portion is likely to be deteriorated in corrosion resistance when compared with other portions. Generally, in order to improve corrosion resistance, it is necessary to carry a chromium-based anticorrosive pigment in the undercoat film of the precoated steel sheet. .

However, the chromium-based rust-preventive pigment is produced by containing hexavalent chromium having excellent rust resistance, and the hexavalent chromium has problems in terms of human health and environmental protection.

Up to now, most of the non-chromium-based rust-preventive pigments have been commercially available such as zinc phosphate, aluminum tripolyphosphate, zinc molybdate, etc., and various primers have been proposed for combining non-chromium pigment primers. For example, Patent Document 1 discloses that a combination of an anti-rust pigment, calcium citrate and vanadate, or a combination of calcium carbonate, calcium silicate and aluminum phosphate, is blended in a vehicle liquid component of an epoxy resin and a phenol resin. A coating of anti-rust pigments of vanadate phosphorus. Further, Patent Document 2 discloses a coating material in which a combination of a magnesium phosphite, a manganese oxide ^‧ a vanadium oxide fired product, or a burned material of calcium phosphate and vanadium oxide is blended as a rust preventive pigment in a polyester. However, the coating film formed from the coating materials described in Patent Documents 1 and 2 is inferior in corrosion resistance as compared with the coating material using the chromium-based pigment, and in particular, the corrosion resistance of the processed portion and the end surface portion is insufficient. Moreover, most of the corrosion resistance or acid resistance is not good. In addition, when a large amount of anti-rust pigment is used, most of the water resistance is not good, and the effect of replacing the chromium-based anti-rust pigment cannot be achieved when the pre-coated metal sheet is manufactured.

Further, Patent Document 3 describes a coating composition which contains an oil absorption of 30 to 200 ml/100 g and a pore volume in a vehicle component composed of an organic resin containing a hydroxyl group or an epoxy group and a curing agent. It is a coating of 0.05 to 1.2 ml/g of cerium oxide microparticles, and the glass transition temperature of the cured coating film formed by the coating is in the range of 40 to 125 °C. However, the coating film formed of the coating material described in Patent Document 3 has considerable corrosion resistance, but is also inferior in corrosion resistance and chemical resistance when compared with a coating using a chromium-based pigment. In particular, the corrosion resistance of the end face is insufficient.

Further, Patent Document 4 describes a coating composition excellent in corrosion resistance, which is a coating composition containing a coating film-forming resin containing a hydroxyl group, a crosslinking agent, and a mixture of rust-preventive pigments, wherein the rust-preventing pigment mixture It is composed of a specific vanadium compound, cerium oxide microparticles, and a phosphate metal salt (the metal salt is calcium, zinc, aluminum, magnesium salt, etc.), which exhibits excellent corrosion resistance, but is caused by exposure to the outside. The resistance of the corrosion reaction after the deterioration of the surface coating film, that is, the improvement of the corrosion resistance, is still sought to improve and improve the corrosion resistance.

[Patent Document 1] Japanese Patent Laid-Open No. Hei 11-61001

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2000-199078

[Patent Document 3] Japanese Patent Laid-Open Publication No. 2000-129163

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2008-222833

An object of the present invention is to provide a non-chromium-based paint composition which can form a coating film having excellent corrosion resistance not only in a general portion such as a metal plate but also a corrosion-resistant portion in a processed portion or an end portion thereof. An excellent coating film (even if the coating film starts to deteriorate due to photolysis or hydrolysis in an outdoor environment); and a coated metal plate using the same.

Therefore, the inventors of the present invention have made an effort to solve the above-mentioned problems, and have found that a resin containing a phosphate group and/or a phosphate group-containing resin are blended in a coating film-forming resin containing a hydroxyl group. The vanadium compound and the coating composition of the rust-preventive pigment of the ion-exchanged cerium oxide can form a coating film having excellent corrosion resistance not only in the flat portion in the outdoor environment, but also in a processing portion such as a coated metal plate. The end face may also have a coating film excellent in corrosion resistance, and the present invention has been completed.

That is, the present invention provides a coating composition excellent in corrosion resistance, which comprises: (A) a coating film-forming resin containing no hydroxyl group and having a hydroxyl group, (B) a crosslinking agent, and (C) a rust-preventing pigment mixture And (D) a phosphate group-containing resin and/or a phosphate group-containing resin [hereinafter sometimes simply referred to as "a phosphate (base)-containing resin (D)"), which is characterized in that the rust-preventive pigment mixture (C) Is composed of (1) a vanadium compound of at least one of vanadium pentoxide, calcium vanadate and ammonium methylvanadate, and (2) ion-exchanged ruthenium dioxide; relative to the resin (A) and the crosslinking 100 parts by mass of the total solid content of the agent (B), the amount of the vanadium compound (1) is 3 to 50 parts by mass, the amount of the ion-exchanged cerium oxide (2) is 3 to 50 parts by mass, and the phosphoric acid (salt) is contained. The total amount of the base resin (D) is 1 to 30 parts by mass, and the amount of the rust preventive pigment mixture (C) is 6 to 100 parts by mass.

Further, the present invention also provides a coated metal sheet obtained by forming a cured coating film on a metal sheet having a chemical conversion coating on its surface by the above coating composition.

In addition, the present invention also provides a coated metal sheet having a plurality of coating films formed on a metal sheet having a chemical conversion treatment on the surface thereof, wherein a hard coating film is formed by the coating composition, and formed on the hard coating film. There are surface coatings.

Further, the present invention also provides a coated metal sheet obtained by forming a cured coating film on the both surfaces of a metal sheet having a surface chemical treatment.

In addition, the present invention also provides a coated metal sheet having a plurality of coating films formed on the both sides of a metal sheet on which a surface can be subjected to a chemical treatment to form a hardened coating film on at least one side thereof. A surface coating film is formed on the hardened coating film.

The coating composition of the present invention is a coating composition which does not contain a chromium-based rust-preventive pigment and is advantageous for environmental hygiene. The coating composition of the present invention can exhibit excellent corrosion resistance in forming a flat portion, and up to At present, a non-chromium-based rust-proof paint is difficult to achieve, and a coating film having an effect of coating a metal plate or the like has excellent corrosion resistance. Further, the coating composition of the present invention has a phosphate (salt)-containing resin (D) and acts as a strong adhesion-imparting component in an acid gas atmosphere. Its excellent adhesion imparting property is believed to interact with the specific vanadium compound and ion-exchanged cerium oxide of the rust preventive pigment to help greatly improve the temporal corrosion resistance of the outdoor environment.

That is, the anti-rust pigment mixture (C) composed of the vanadium compound (1) and the ion-exchanged ceria (2) has an effect of effectively covering the exposed surface of the material, and contains phosphoric acid (salt). The base resin (D) component acts as a strong adhesion-imparting component in an acidic atmosphere, and thus has a function of suppressing corrosion and peeling off the coating film in a portion of the adjacent anode, and is capable of providing a coating composition and use according to the present invention. The coated metal plate can form a coating composition which can be degraded even if the coating film is photolyzed or hydrolyzed in an outdoor environment, but the coating film can not only effectively improve the corrosion resistance of the flat portion of the coated metal plate, but also Effectively improve the corrosion resistance of the processed part or the end face.

A coated metal sheet having a cured coating film formed by the coating composition of the present invention, which has excellent corrosion resistance at a flat portion, a processed portion or an end portion, and has a conventional chromium by using strontium chromate or the like The coating of the anti-rust pigment of the acid salt forms a corrosion resistance equal to or higher than that of the coated metal sheet having the cured coating film.

A coating metal sheet having a cured coating film formed on the cured coating film and having a surface coating film formed thereon is excellent in corrosion resistance at a flat portion, a processed portion or an end portion. When a galvanized steel sheet or an aluminum-zinc alloy plated steel sheet is used as the metal sheet of the object to be coated, excellent corrosion resistance can be obtained in the flat portion, the end surface portion, and the processed portion by applying the coating composition of the present invention.

The coating composition of the present invention contains the following components: a coating film-forming resin (A) containing a hydroxyl group, a crosslinking agent (B), a rust-preventive pigment mixture (C), and a resin containing a phosphate (salt) group (D) .

Hydroxyl-coated film-forming resin (A)

The coating film-forming resin containing a hydroxyl group in the coating composition of the present invention may be a hydroxyl group-containing resin having a coating film forming ability which can be generally used in the field of coating, and is not particularly limited, and is typically, for example, a hydroxyl group-containing polyester resin or a ring. One or more mixed resins of an oxygen resin, an acrylic resin, a fluorine resin, and a chlorinated vinyl resin. A film-forming resin, wherein at least one organic resin selected from the group consisting of a hydroxyl group-containing polyester resin and an epoxy resin can be suitably used.

The above hydroxyl group-containing polyester resin comprises an oil-free polyester resin, an oil-modified alkyd resin, and a modified product of the resins, which include, for example, a urethane-modified polyester resin, a urethane A modified alkyd resin, an epoxy-modified polyester resin, an acrylic modified polyester resin, or the like. The hydroxyl group-containing polyester resin has a number average molecular weight of 1,500 to 35,000, preferably 2,000 to 25,000, a glass transition temperature (Tg point) of 10 to 100 ° C, preferably 20 to 80 ° C, and a hydroxyl value of 2 It is preferably -100 mgKOH/g, preferably 5 to 80 mgKOH/g.

In the present invention, the "number average molecular weight" of the resin is determined by a gel permeation chromatography method ("HLC8120GPC", manufactured by Tosoh Corporation, "HLC8120GPC"), and the standard polystyrene is used. The molecular weight of ethylene is the value determined by the standard. For the column, four "TSKgel G-4000HXL", "TSKgel G-3000HXL", "TSKgel G-2500HXL", and "TSKgel G2000HXL" (both manufactured by Tosoh Corporation) are used. Tetrahydrofuran, measuring temperature: 40 ° C, flow rate: 1 cc / min, detector: RI conditions were carried out. Further, in the present specification, the glass transition temperature (Tg) of the resin is by means of differential thermal analysis (DSC).

The above oil-free polyester resin is an esterified product of a polybasic acid component and a polyol component. The polybasic acid component is mainly used in one or more selected from, for example, phthalic anhydride, isophthalic acid, p-nonanoic acid, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, succinic acid, fumaric acid, adipic acid, sebacic acid, maleic anhydride. The dibasic acid and the lower alkyl ester of the acid, depending on the desired one, may be used as a monobasic acid such as benzoic acid, crotonic acid or p-tert-butylbenzoic acid, trimellitic anhydride, methylcyclohexene A trivalent or higher polybasic acid such as a carboxylic acid or a pyromellitic anhydride. The polyol component is mainly used, for example, ethylene glycol, diethylene glycol, propylene glycol, 1,4-butanediol, neopentyl alcohol, 3-methylpentanediol, 1,4-hexanediol, 1,6-hexane A diol such as an alcohol may be a trivalent or higher polyhydric alcohol such as glycerin, trimethylolethane, trimethylolpropane or pentaerythritol as needed. These polyols may be used singly or in combination of two or more. The esterification or transesterification of the two components can be carried out by a method known per se. The acid component is preferably isodecanoic acid, p-citric acid, and a lower alkyl ester of such acids.

The alkyd resin may be an acid fatty acid such as coconut oil fatty acid, soybean oil fatty acid or castor oil fatty acid, in addition to the acid component and the alcohol component of the above oil-free polyester resin. , sunflower oil fatty acid, tall oil fatty acid, dehydrated castor oil fatty acid, tung oil fatty acid. The oil length of the alkyd resin is preferably 30% or less, particularly preferably about 5 to 20%.

a urethane-modified polyester resin, for example, the above-mentioned oil-free polyester resin or a low molecular weight oil-free polyester resin obtained by reacting an acid component and an alcohol component used in the production of the above oil-free polyester resin, and The polyisocyanate compound is reacted in a manner known per se. Further, the urethane-modified alkyd resin contains a low molecular weight alkyd resin obtained by reacting the above alkyd resin or each component used in the production of the above alkyd resin, and a polyisocyanate compound is known per se. The method of responding. a urethane-modified polyester resin and a polyisocyanate compound used in the manufacture of a urethane-modified alkyd resin, such as hexamethylene diisocyanate, isophorone diisocyanate, benzodimethyl di Isocyanate, tolyl diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-methylene bis(cyclohexyl isocyanate), 2,4,6-triisocyanate toluene, and the like. The above-mentioned urethane-modified resin is generally used in an amount of 30% by weight or less based on the amount of the polyisocyanate compound forming the urethane resin relative to the urethane-modified resin. The degree of modification is appropriate.

The epoxy group-modified polyester resin can be, for example, a polyester resin produced from the respective components used in the production of the above polyester resin, a reaction product of a carboxyl group of the resin and an epoxy group-containing resin, or a polyester. A reaction product in which a hydroxyl group in a resin and a hydroxyl group in an epoxy resin are bonded via a polyisocyanate compound, and a reaction of addition, condensation, grafting, or the like of a polyester resin and an epoxy resin. The degree of modification of the epoxy-modified polyester resin is generally 0.1 to 30% by weight based on the epoxy group-modified polyester resin.

The acrylic modified polyester resin can be, for example, a polyester resin produced by using each component used in the production of the above polyester resin, and the carboxyl group or the hydroxyl group of the resin contains a group reactive with such a group (for example, a carboxyl group). a reaction product of an acrylic resin of a hydroxyl group or an epoxy group, or a graft polymerization of a polyester resin with a (meth)acrylic acid or a (meth)acrylate or the like using a peroxide-based polymerization initiator. Reaction product. The degree of modification of the acrylic modified polyester resin is generally from 0.1 to 50% by weight based on the amount of the acrylic modified polyester resin.

Among the above-mentioned polyester resins, an oil-free polyester resin or an epoxy-modified polyester resin is preferable in terms of balance between workability and corrosion resistance.

A preferred epoxy resin for forming a resin containing the hydroxyl group-containing coating film, for example, a bisphenol type epoxy resin or a novolac type epoxy resin; and an epoxy group or a hydroxyl group in the epoxy resin reacts with various modifiers Modified epoxy resin. When the modified epoxy resin is produced, the modification period of the modifier is not particularly limited, and may be modified in the middle of the process of manufacturing the epoxy resin, or may be modified in the final stage of manufacturing the epoxy resin. Sex.

The bisphenol type epoxy resin is condensed to a resin having a high molecular weight in the presence of a catalyst such as an alkali catalyst, such as epichlorohydrin and bisphenol, to give epichlorohydrin and bisphenol. It is required to carry out condensation in the presence of a catalyst such as a base catalyst to form a low molecular weight epoxy resin, and to obtain a resin obtained by polyaddition reaction of the low molecular weight epoxy resin and bisphenol.

The above bisphenols, such as 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-third Butyl-phenyl)-2,2-propane, p-(4-hydroxyphenyl)phenol, oxobis(4-hydroxyphenyl), sulfonylbis(4-hydroxyphenyl), 4,4 '-Dihydroxybenzophenone, bis(2-hydroxynaphthyl)methane, etc., among which bisphenol A and bisphenol F are preferably used. One type or a mixture of two or more types may be used for the above bisphenols.

A commercially available product of a bisphenol type epoxy resin, for example, made by Japan Epoxy Resin Co., Ltd. 828, the same 812, the same 815, the same 820, the same 834, the same 1001, the same 1004, the same 1007, the same 1009, the same 1010; Asahi Chiba company's Yalaru Brighton AER6099; and Mitsui Chemicals (shares) system Bomi Valley (transliteration) R-309 and so on.

Further, the above-mentioned novolac type epoxy resin which is a preferred epoxy resin for forming a resin containing a hydroxyl group, such as a phenol novolak type epoxy resin or a cresol novolak type epoxy resin, has a majority of epoxy in the molecule. A variety of novolac type epoxy resins, such as phenol oxirane type epoxy resins.

The modified epoxy resin is an epoxy resin which reacts the bisphenol epoxy resin or the novolak epoxy resin with, for example, an inert oil fatty acid; and a polymerizable property containing acrylic acid or methacrylic acid. An epoxy acrylate resin which reacts with an unsaturated monomer component; a urethane-modified epoxy resin which reacts with an isocyanate compound; and the above bisphenol type epoxy resin, novolak type epoxy resin or the above various The epoxy group in the modified epoxy resin is reacted with an amine compound to introduce an amine group-modified epoxy resin or the like formed of an amine group or a grade 4 ammonium salt.

Crosslinking agent (B)

The crosslinking agent (B) is a resin (A) which reacts with the hydroxyl group-containing coating film forming resin (A) to form a cured coating film, and can be formed by forming a resin (A) with the hydroxyl group-containing coating film by heating or the like. The reaction is preferably cured, and is not particularly limited, and an amine-based resin, a phenol resin, and a polyisocyanate compound which can be blocked are preferably used. These crosslinking agents can be used alone or in combination of two or more.

The above-mentioned amine-based resin is, for example, a hydroxyl group obtained by reacting an amine component such as melamine, urea, benzoguanamine, acetylguanamine, steroid decylamine, spiroamine or dicyanamide with an aldehyde. Alkylated amine based resin. The aldehyde used in the above reaction is, for example, formaldehyde, p-formaldehyde, acetaldehyde, benzaldehyde or the like. Further, the above-mentioned methylolated amine-based resin may be used as an amine-based resin by etherification with a suitable alcohol. The alcohol used in the etherification, for example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, 2-ethylbutanol, 2-ethylhexanol or the like.

The phenol resin which can be used as the crosslinking agent is a crosslinking reaction with the hydroxyl group-containing coating film-forming resin (A), and the phenol component and the formaldehyde are heated and condensed in the presence of a reaction catalyst. A novolac type phenol resin formed by introducing a methylol group, a partial or total hydroxyl group of the obtained methylolated phenol resin, and alkyl etherification with an alcohol.

When a novolac type phenol resin is produced, a bifunctional phenol compound, a trifunctional phenol compound, a tetrafunctional or higher phenol compound, or the like can be used as the starting phenol component.

The above phenol compound is, for example, 2-functionality such as o-cresol, p-cresol, p-tert-butylphenol, p-ethylphenol, 2,3-xylenol, 2,5-xylenol or the like. The phenol compound is a trifunctional phenol compound such as phenol carbonate, m-cresol, m-ethylphenol 3,5-xylenol or m-methoxyphenol, and bisphenol A, bisphenol F or the like is used as 4 Functional phenolic compound. Among them, in order to improve the scratch resistance, it is preferred to use a trifunctional or higher phenol compound, particularly, stone carbonate and/or m-cresol. These phenol compounds may be used singly or in combination of two or more kinds.

The formaldehyde to be used in the production of the phenol resin, for example, formaldehyde, paraformaldehyde or trioxane, may be used singly or in combination of two or more kinds.

The alcohol to be used for the alkylation of a part of the methylol group of the methylolated phenol resin is preferably a monohydric alcohol having 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. Preferred monohydric alcohols are, for example, methanol, ethanol, n-propanol, n-butanol, isobutanol and the like.

The phenol resin has an average of 0.5 or more alkoxymethyl groups per nucleus benzene nucleus, preferably 0.6 to 3.0, in terms of reactivity with the hydroxyl group-containing coating film-forming resin (A).

It is also possible to use a polyisocyanate compound which is not blocked in the block polyisocyanate compound as the above-mentioned crosslinking agent, for example, an aliphatic diisocyanate of hexamethylene diisocyanate or trimethylhexamethylene diisocyanate. a cyclic aliphatic diisocyanate such as hydrogenated dimethyl diisocyanate or isophorone diisocyanate; such as tolyl diisocyanate, benzodimethyl diisocyanate or 4,4'-diphenylmethane diisocyanate; The organic diisocyanate of the original MDI aromatic diisocyanate itself, or an adduct of each of the organic diisocyanate and the polyol, the low molecular weight polyester resin or water, or the ring of each of the above organic diisocyanates Polymer, and isocyanate ^‧ carbamide and the like.

The blocked polyisocyanate compound is obtained by blocking a free isocyanate group in the above polyisocyanate compound by a blocking agent. The above-mentioned blocking agent is, for example, a phenol type such as phenol, cresol or xylenol; ε-caprolactam; a decylamine such as δ-valeroguanamine or γ-butylide; methanol, ethanol, An alcohol system of n-, iso- or tert-butanol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, benzyl alcohol, etc.; methotrexate, acetamide Anthraquinones such as hydrazine, ethyl hydrazine, methyl ethyl ketone oxime, diethyl hydrazine monoterpenes, benzophenone oxime, cyclohexane oxime, etc.; dimethyl malonate, diethyl malonate, acetamidine A blocking agent such as an active methylene group such as ethyl acetate or acetaminoacetone is preferred. By mixing the above polyisocyanate compound and the above blocking agent, the free isocyanate group in the above polyisocyanate compound can be easily blocked.

The mixing ratio of the hydroxyl group-containing coating film-forming resin (A) and the crosslinking agent (B) is based on 100 parts by mass of the total solid content of the components (A) and (B), and a hydroxyl group-containing coating film is formed. The resin (A) is 5 to 95 parts by weight, preferably 60 to 95 parts by mass, and the crosslinking agent (B) is in the range of 5 to 45 parts by mass, preferably 5 to 40 parts by mass. Corrosive, boiling water resistance, workability, hardenability, and the like are preferred.

In order to improve the hardenability of the coating composition of the present invention, a hardening catalyst may be blended as needed. The crosslinking agent (B) is an amine-based resin, particularly a mixed etherified melamine resin containing a low molecular weight methyl etherification or methyl ether and dibutyl ether, and an amine neutralizing substance using a sulfonic acid compound or a sulfonic acid compound is used. Hardening catalyst is suitable. Typical examples of the sulfonic acid compound are p-toluenesulfonic acid, dodecylbenzenesulfonic acid, dinonylnaphthalenesulfonic acid, dinonylnaphthalene disulfonic acid and the like. The amine in the amine neutralizer of the sulfonic acid compound may be a primary amine, a secondary amine, or a tertiary amine. Among these, an amine neutralizing substance of p-toluenesulfonic acid and/or an amine neutralizing substance of dodecanebenzenesulfonic acid is used for the stability of the coating, the reaction promoting effect, and the physical properties of the obtained coating film. It is appropriate.

When the crosslinking agent (B) is a phenol resin, an amine neutralizer using the above sulfonic acid compound or sulfonic acid compound is used as a curing catalyst.

When the crosslinking agent (B) is a blocked polyisocyanate compound, it is preferred to use a curing catalyst which promotes dissociation of a blocking agent of a blocked polyisocyanate compound of a crosslinking agent, and a preferred curing catalyst such as tin octylate. Dibutyltin bis(tin-2-ethylhexanoate), dioctyl bis(tin-2-ethylhexanoate), tin dioctyl diacetate, dibutyltin dilaurate, dibutyltin oxide, dioctane An organic metal catalyst such as tin oxide or lead 2-ethylhexanoate.

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

Anti-rust pigment mixture (C)

In the coating composition of the present invention, the rust-preventive pigment mixture (C) is composed of the following (1) vanadium compound and (2) ion-exchanged cerium oxide.

Vanadium compound (1)

The vanadium compound (1) is a vanadium compound of at least one of vanadium pentoxide, calcium vanadate, and ammonium methylvanadate. Vanadium pentoxide, calcium vanadate and ammonium methylvanadate are pentavalent vanadium ions, which have excellent solubility in water, and the vanadium ions released by the vanadium compound (1) react with the raw material metal and come from The ions of the other rust-preventing pigment mixture are reacted, thereby effectively improving the corrosion resistance.

Ion exchange cerium oxide (2)

The ion-exchanged cerium oxide (2) is a fine porous cerium oxide carrier which is introduced into a cerium oxide fine particle having a cation such as a calcium ion by ion exchange. Examples of the ion-exchanged cerium oxide include calcium ion-exchanged cerium oxide, magnesium ion-exchanged cerium oxide, and cobalt ion-exchanged cerium oxide.

The ion-exchanged cerium oxide (2) can preferably be a fine cerium oxide powder having an average particle diameter of 0.5 to 15 μm, preferably 1 to 10 μm, and the oil absorption amount is 30 to 300 ml/100 g, preferably 30 to 150 ml/100 g. Within the scope of the.

It is preferred to ion-exchange cerium oxide (2) in which calcium ions are exchanged for cerium oxide. Commercial products of calcium ion-exchanged cerium oxide include SHIELDEX (registered trademark) C303, AC-3, and C-5 (all manufactured by W.R. Grace & Co.).

The cations such as calcium ions released by ion-exchanged cerium oxide are related to electrochemical action and the formation of various salts, and can effectively improve corrosion resistance. Further, the cerium oxide fixed in the coating film can effectively suppress peeling of the coating film under a corrosive atmosphere.

Resin containing phosphoric acid (salt) group (D)

Among the resins (D) containing a phosphoric acid (salt) group, the resin containing a phosphate group contains a phosphate group [-OPO(OH)(OR ¹ )] (wherein R ¹ is a hydrogen atom, a phenyl group or a carbon number of 1) In the case of the type of the resin, as long as the phase is dissolved in the film-forming resin (A) containing a hydroxyl group and the crosslinking agent (B), the alkyl group of -20 is particularly preferably a hydrogen atom or an alkyl group of 2 to 10). There is no particular limitation, and examples thereof include an acrylic resin containing a phosphoric acid group, an epoxy resin containing a phosphoric acid group, and a polyester resin containing a phosphoric acid group.

The phosphoric acid group-containing acrylic resin can be obtained, for example, by copolymerizing a phosphoric acid group-containing unsaturated monomer with another polymerizable unsaturated monomer.

Examples of the above-mentioned unsaturated group containing a phosphoric acid group include (2-propenyloxyethyl) acid phosphate, (2-methylpropenyloxyethyl) acid phosphate, and (2-acryloxy) Acid phosphate, (2-methacryloxypropyl) acid phosphate, 10-propylene decyl decyl acid phosphate, 10-methyl propylene decyl hydroxy acid phosphate, etc. Acetyloxyalkyl (carbon number 2 to 20) acid phosphate; in the case of orthophosphoric acid or acid phosphate (carbon number 1 to 20), the molar addition of epoxy methacrylate, etc. Base unsaturated monomer; Kayamer PM-2, same as PM-21 (above, manufactured by Nippon Kayaku Co., Ltd., trade name). Examples of the acidic phosphate ester herein include methyl acid phosphate, butyl acid phosphate, 2-ethylhexyl acid phosphate, isodecyl acid phosphate, lauryl acid phosphate, and isotridecyl acid. Phosphate ester, oleyl acid phosphate, phenyl acid phosphate, and the like.

Examples of the other polymerizable unsaturated monomer which is copolymerized with the phosphoric acid group-containing unsaturated monomer to form the phosphoric acid group-containing acrylic resin include, for example, 2-hydroxyethyl (meth)acrylate and (meth)acrylic acid 2. a hydroxyl group-containing unsaturated monomer such as -hydroxypropyl ester, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl vinyl ether, 2-hydroxypropyl vinyl ether or 2-hydroxyethyl propylene ether; acrylic acid, Methacrylic acid; vinyl aromatic compound such as styrene, α-methylstyrene, vinyltoluene or α-styrene chloride; methyl (meth)acrylate, ethyl (meth)acrylate, (methyl) N-propyl acrylate, isopropyl (meth) acrylate, (meth)acrylic acid (n-, iso-, third) butyl ester, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (methyl) ) 2-ethylhexyl acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, lauryl (meth) acrylate, stearate (meth) acrylate, (meth) acrylate An alkyl or cycloalkyl ester having 1 to 24 carbon atoms of acrylic acid or methacrylic acid such as oxime ester; vinyl acetate, vinyl chloride, vinyl ether, acrylonitrile, methacrylonitrile, etc.In the present invention, "(meth) acrylate" means "acrylate or methacrylate".

Further, the phosphoric acid group-containing acrylic resin may be a phosphate compound by a copolymerized resin comprising an epoxy group-containing unsaturated monomer such as glycidyl methacrylate and the above other polymerizable unsaturated monomer. The method is obtained. The phosphoric acid compound to be added is preferably orthophosphoric acid or acid phosphate, and examples of the acidic phosphate esters include those exemplified above as the acidic phosphate ester.

The above-mentioned epoxy group-containing epoxy resin can be obtained by adding an epoxy resin to a phosphoric acid compound. Examples of the epoxy resin to which the phosphoric acid compound is added include a bisphenol epoxy resin and a novolac epoxy resin, and an epoxy group or a hydroxyl group in the epoxy resin is reacted with various modifiers. Epoxy resin, etc. The type of the phosphate compound to be added can be similarly used in the description of the above-mentioned phosphoric acid group-containing acrylic resin as a copolymerization resin composed of an epoxy group-containing unsaturated monomer and another polymerizable unsaturated monomer. The phosphate compounds are listed.

The phosphoric acid group-containing polyester resin can be obtained, for example, by reacting a hydroxyl group of a polyester resin with a phosphate compound. The type of the phosphate compound to be reacted can be similarly used as a phosphate compound in the description of the phosphoric acid group-containing acrylic resin.

Among the resin (D) containing a phosphoric acid (salt) group, the phosphate group-containing resin can be obtained by reacting a phosphate group in the above phosphoric acid group-containing resin with a metal compound as a phosphate. Examples of the metal compound which reacts with the above phosphoric acid group include calcium oxide, magnesium oxide, cobalt oxide, nickel oxide, zinc oxide, cerium oxide, cerium oxide and the like.

The phosphate group or the phosphate group of the phosphoric acid (salt)-based resin (D) can effectively enhance the adhesion imparting property or the corrosion resistance in an acidic atmosphere.

In the coating composition of the present invention, the vanadium compound (1) and the ion-exchanged cerium oxide of the rust preventive pigment mixture (C) are compared with 100 parts by mass of the total solid content of the resin (A) and the crosslinking agent (B). (2), and the amount of the resin (D) containing a phosphate (salt) group is in the following range, and the amount of the rust preventive pigment mixture (C) is preferably from 6 to 100 from the viewpoint of corrosion resistance. The mass part is more preferably 10 to 60 parts by mass.

Vanadium compound (1): 3 to 50 parts by mass, preferably 5 to 40 parts by mass, ion-exchanged cerium oxide (2): 3 to 50 parts by mass, preferably 3 to 30 parts by mass, containing phosphoric acid (salt) The base resin (D): 1 to 30 parts by mass, preferably 1 to 20 parts by mass.

The coating composition of the present invention can be obtained by using the vanadium compound (1) as the rust preventive pigment mixture (C) and the ion-exchanged cerium oxide (2), and the resin (D) containing the phosphoric acid (salt) group. It combines quantitatively and multiplies to improve corrosion resistance.

Further, from the viewpoints of the solubility of water and the reactivity between the dissolved solution of the vanadium compound (1) and the ion-exchanged cerium oxide (2) and the rust-preventing pigment and the metal plate, it is preferred to: relative to the above resin (A) and a total of 100 parts by mass of the solid content of the crosslinking agent (B), the mass fraction of each of the pigments of the vanadium compound (1) and the ion-exchanged cerium oxide (2) constituting the rust preventive pigment mixture (C) The mixture was stirred and added to 10000 parts by mass of a 5 mass% aqueous sodium chloride solution at 25 ° C for 6 hours, and then allowed to stand at 25 ° C for 48 hours, and then the pH of the filtrate obtained after filtering the supernatant liquid was 3 to 8, It is preferably 5 to 8, and it is preferable in this range to be in terms of corrosion resistance.

In other words, the filtrate subjected to the pH measurement described above is a filtrate obtained by dissolving a solution of the following: a 10000 mass part of a sodium chloride aqueous solution having a concentration of 5 mass% at 25 ° C, and a vanadium compound (1) at a mass of 3 to 50 Any amount within the range of the fraction, the ion-exchanged cerium oxide (2) is in any amount within the range of from 3 to 50 parts by mass.

The coating composition of the present invention comprises, in addition to the above-mentioned hydroxyl group-containing coating film-forming resin (A), crosslinking agent (B), rust-preventive pigment mixture (C), phosphoric acid (salt)-based resin (D), and optionally In addition to the hardening catalyst to be blended, it may be used in the paint field, such as colored pigments, extender pigments, ultraviolet absorbers, ultraviolet stabilizers, organic solvents, additives such as sedimentation inhibitors, defoamers, and coating conditioners.

Examples of the coloring pigment include organic coloring pigments such as cyanine blue, cyanine green, azo or quinacridyl organic red pigments; titanium white, titanium yellow, iron oxide, carbon black, and various calcined pigments. An inorganic colored pigment such as titanium white can be preferably used.

Examples of the above-mentioned extender pigments include talc, clay, mica, alumina, calcium carbonate, barium sulfate, and the like.

Examples of the above ultraviolet absorber include 2-(2-hydroxy-3,5-di-third-pentylphenyl)-2H-benzotriazole and isooctyl-3-(3-(2H-benzo). Triazol-2-yl)-5-tert-butyl-4-hydroxyphenylpropionate, 2-[2-hydroxy-3,5-di(1,1-dimethyl petroleum ether)phenyl] -2H-benzotriazole, 2-[2-hydroxy-3-dimethylbenzyl-5-(1,1,3,3-tetramethylbutyl)phenyl]-2H-benzotriene Benzene, condensate such as methyl-3-[3-t-butyl-5-(2H-benzotriazol-2-yl)-4-hydroxyphenyl]propionate/polyethylene glycol 300 And triazole derivative; 2-[4-(2-hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl-4,6-bis(2,4-dimethyl Phenyl)-1,3,5-three Wait three a derivative; ethanediamine-N-(2-ethoxyphenyl)-N'-(2-ethylphenyl)-(ethylenediamine), ethanediamine-N-( An oxalic acid aniline derivative such as 2-ethoxyphenyl)-N'-(4-isododecylphenyl)-(ethylenediamine).

Examples of the ultraviolet stabilizer include a hindered amine compound and a hindered phenol compound; CHIMASORB 944, TINUVIN 144, TINUVIN 292, TINUVIN 770, IRGANOX 1010, and IRGANOX 1098 (products of the above-mentioned trade names are all products of Ciba Specialty Chemicals Co., Ltd.).

By incorporating an ultraviolet absorber or an ultraviolet stabilizer in the coating, deterioration caused by light on the surface of the coating film can be suppressed, and even when the coating is used as a primer, it is possible to suppress the passage of the surface coating film to the primer coating film. The deterioration of the surface of the primer caused by the light of the surface prevents the interlayer peeling of the primer coating film and the surface coating film due to the deterioration of the surface of the primer coating film, and maintains excellent corrosion resistance.

The organic solvent which can be blended in the coating composition of the present invention can be blended in order to improve the coatability of the composition of the present invention, and a film-forming resin (A) and a crosslinking agent (B) which can contain a hydroxyl group can be used. Specific examples of the solvent which is dissolved and dispersed include a hydrocarbon solvent such as toluene, xylene, or a high-boiling petroleum hydrocarbon, and a ketone such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone or isophorone. An ester solvent such as a solvent, ethyl acetate, butyl acetate, ethylene glycol monoethyl ether acetate or diethylene glycol monoethyl ether acetate; an alcohol solvent such as methanol, ethanol, isopropanol or butanol; An ether alcohol-based solvent such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether or diethylene glycol monobutyl ether may be used alone or in combination of two or more.

In the coating composition of the present invention, in terms of corrosion resistance, acid resistance and processability of the coating film, it is preferred that the glass transition temperature of the cured coating film obtained from the composition of the present invention is 40 to 115 ° C, preferably. It is 50 to 105 °C. The glass transition temperature of the coating film was measured by the DINAMIC VISCOELASTOMETER MODEL VIBRON (Dynamic Viscoelasticity Type VIBRON) DDV-IIEA type (automatic dynamic viscoelasticity measuring machine manufactured by Toyo Baldwin Co., Ltd.), and the tan δ change measured by temperature dispersion at a frequency of 110 Hz. , to find the maximum temperature.

The coating film formed by coating the coating composition of the present invention on a metal plate exhibits excellent corrosion resistance. The reason for the present invention is as follows: The first reason is that metal ions generated by dissolution of a raw material metal due to chloride ions or the like in a corrosive environment and pentavalent vanadium ions (VO ₃ ^- or VO ₄ ^3- vanadate ions) are not a precipitating salt directly formed by a redox reaction, and a trivalent vanadium ion and a raw material metal ion formed by a redox reaction between a pentavalent vanadium ion and a raw material metal, and hydrolysis by ion exchange of ceria in a corrosive environment The released cation or citric acid ion effectively forms a precipitable salt or compound, and the exposed surface of the raw material is effectively coated.

In addition, the second reason is that the ion-exchanged cerium oxide not only has the effect of releasing cations in a corrosive atmosphere, but also effectively adjusts the pH of the adjacent wet atmosphere to the effect of the surface of the weakly acidic functional group. The weak acidity promotes the redox reaction between the pentavalent vanadium ion and the raw material metal. Furthermore, the ion-exchanged ceria is fixed to the coating film, so the pH adjustment ability can be maintained even if it is corroded for a long time. Even in a strong corrosive atmosphere, it will self-fertilize and hydrolyze, and continuously release citrate ions.

Furthermore, the third reason is that the surface coating film in the coated steel sheet is considered to be hydrophilized by deterioration, and the surface of the surface coating film is permeable to various corrosion promoting factors and contains a phosphate (base)-based resin (D). ) acts as a strong adhesion-imparting component in an acidic atmosphere, thereby suppressing corrosion by peeling off the coating film in a portion of the adjacent anode, and effectively neutralizing the hydroxyl group generated by the reduction reaction of oxygen in the cathode, while maintaining its pH Near neutral.

Further, the phosphoric acid group of the phosphoric acid (salt) group-containing resin (D) is considered to have an effect of keeping the pH of the atmosphere weakly acidic, and the vanadium ion or the phthalic acid ion can be appropriately reacted on the raw metal surface or Produce salt. It is believed that a very high degree of corrosion resistance is achieved by the combination of these various mechanisms.

Further, by using the above-mentioned vanadium compound (1) constituting the rust preventive pigment mixture (C), ion-exchanged cerium oxide (2), and a resin (D) containing a phosphoric acid (salt) group, the above-mentioned vanadium compound can be effectively offset ( 1) The ion-exchanged cerium oxide (2) and the phosphoric acid (salt)-based resin (D) have the disadvantages of acid resistance, alkali resistance and water resistance, respectively. According to the action of the rust preventive pigment mixture (C) and the resin (D) containing a phosphoric acid (salt) group, the synergistic effect can be greatly exhibited, and excellent corrosion resistance can be achieved.

That is, the anti-rust pigment mixture (C) composed of the vanadium compound (1) and the ion-exchanged ceria (2) has an effect of effectively covering the exposed surface of the raw material, and contains phosphoric acid (salt). The base resin (D) component acts as a strong adhesion-imparting component in an acidic atmosphere, and thus has a function of suppressing corrosion and peeling off the coating film in a portion of the adjacent anode, and is capable of providing a coating composition and use according to the present invention. The coated metal plate can not only effectively improve the corrosion resistance of the flat portion of the coated metal plate, but also effectively improve the corrosion resistance of the processed portion or the end portion, even if the coating film is in the outdoor environment due to photolysis Or hydrolyzed and began to deteriorate.

Painted metal plate

The coating composition of the present invention can be coated and cured by coating on a metal plate to obtain a coated metal sheet. The coated metal plates are, for example, cold-rolled steel sheets, hot-dip galvanized steel sheets, electric galvanized steel sheets, iron-zinc alloy plated steel sheets (galvanyl steel sheets), and aluminum-zinc alloy plated steel sheets (the alloy contains about 55% aluminum). "Gallium-plated galvanium steel plate", alloy containing approximately 5% aluminum "galvanium alloy coating (galfan)", etc.), nickel-zinc alloy plated steel plate, stainless steel plate, aluminum plate, steel plate, plated steel plate, tin plated Steel plates, etc., the surface of these metal plates can also be chemically processed. Examples of the chemical conversion treatment include phosphate treatment such as zinc phosphate treatment or iron phosphate treatment, composite oxide treatment, chromium phosphate treatment, and chromate treatment.

The composition of the present invention can be applied to the above-mentioned metal plate by a conventional method such as a roll coating method, a curtain flow coating method, a spray method, a brush coating method, or a dipping method. The thickness of the cured film of the coating film obtained from the composition of the present invention is not particularly limited, and is usually in the range of 2 to 10 μm, preferably 3 to 6 μm. The hardening treatment of the coating film is appropriately set depending on the type of the resin to be used, and when the coating is performed by a coil coating method or the like, the raw material reaches a maximum temperature of 160 to 250 ° C, preferably 180 to 230. The firing was carried out for 15 to 60 seconds under the conditions of °C. When baking is carried out in a batch type, it can also be baked at 80 to 200 ° C for 10 to 30 minutes. Further, when a polyisocyanate which is not blocked is used as the crosslinking agent (B), or if a bisphenol type epoxy resin is used as the resin (A), an amine compound is used as the crosslinking agent (B) In the case where the crosslinking reaction does not need to be specifically combined with heating in the formation of the coating film, it can be hardened under normal temperature drying in accordance with a usual method.

The coated metal sheet of the present invention is a coated metal sheet provided on the metal sheet which can be chemically treated by the coating composition of the present invention described above, and provided to the coating film formed by the coating composition of the present invention. In addition, a coating film may be provided on the coating film. The film thickness of the surface coating film is usually 8 to 30 μm, preferably 10 to 25 μm.

The surface coating material for forming the above-mentioned surface coating film may, for example, be a conventional polyester resin system, an alkyd resin system, an anthracene modified polyester resin system, a fluorene modified acrylic resin system or a fluorine resin resin which is used for a precoated steel sheet. Surface coating. When the workability is particularly emphasized, a coated steel sheet having particularly excellent workability can be obtained by using a polyester-based surface coating material for high processing. The coated metal sheet of the present invention can have coating film properties excellent in corrosion resistance.

When a galvanized steel sheet or an aluminum-zinc alloy plated steel sheet is used as the metal sheet of the object to be coated, the corrosion resistance of the flat portion can be greatly improved, and the corrosion resistance of the cut end portion and the processed portion after the molding process is hitherto. The properties are still insufficient, but by coating the coating composition of the present invention, excellent corrosion resistance can be obtained at the end surface portion and the processed portion.

Further, a coating film formed by the coating composition of the present invention may be provided on both sides of the object to be coated, and the above surface layer coating film may be further formed on the coating film formed by the coating composition of the present invention as needed. By forming the coating composition of the present invention on both sides, that is, also on the back surface, it is possible to obtain a coated metal sheet which does not contain a chromium-based rust-preventive pigment, is advantageous in terms of environmental hygiene, and is excellent in corrosion resistance.

Example

Hereinafter, the present invention will be more specifically described by way of Production Examples and Examples. However, the invention is not limited by the following examples. Moreover, in the following, "parts" and "%" are based on quality.

Production Example 1 Production of Soluble-Form Phenol Resin Crosslinking Solution

100 parts of bisphenol A, 178 parts of 37% aqueous formaldehyde solution and 1 part of sodium hydroxide were blended in a reaction vessel, and after reacting at 60 ° C for 3 hours, dehydration was carried out under reduced pressure at 50 ° C for 1 hour. Then, 100 parts of n-butanol and 3 parts of phosphoric acid were added, and the reaction was carried out at 110 to 120 ° C for 2 hours. After completion of the reaction, the resulting solution was filtered, and the resulting sodium phosphate was filtered to obtain a resol-type phenol resin crosslinking agent solution B1 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 one equivalent of the benzene nucleus of 0.4, and an average number of alkoxymethyl groups of 1.0.

Production Example 2 Manufacturing of coating for back surface

80 parts of jER1009 (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol A type epoxy resin, hydroxyl group-containing resin) were dissolved in 120 parts of a mixed solvent 1 [cyclohexanone / ethylene glycol monobutyl ether / Solvesso 150 ( 40 parts of epoxy resin solution of Esso Petroleum Co., Ltd., high boiling point aromatic hydrocarbon solvent) = 3/1/1 (mass ratio)], 40 parts of titanium white, 40 parts of cerium oxide and an appropriate amount of mixed solvent 2 [ Solvesso 150 (manufactured by Esso Petroleum Co., Ltd., high-boiling aromatic hydrocarbon solvent) / cyclohexanone = 1 / 1 (mass ratio) was mixed, and pigment dispersion was carried out until the particles (particle diameter of the pigment coarse particles) were 20 μm or less. Next, 26.7 parts (solid content: 20 parts) of Desmodur BL-3175 (Sumika Bayer Urethane Co., Ltd., a solution of HDI isocyanate type polyisocyanate compound blocked with methyl ethyl ketone oxime, and a solid content were added to the dispersion. 75%), two parts of TAKENATE TK-1 (manufactured by Takeda Pharmaceutical Co., Ltd., organotin blocker dissociation catalyst, about 10% solid content) are uniformly mixed, and then the above mixed solvent 2 is added to adjust the viscosity to about 80 seconds. (Ford Cup #4/25 ° C), the paint for the back is made.

Manufacture of a resin containing a phosphate (salt) group

Production Example 3 Production of Phosphate-Based Acrylic Resin 1

While 100 parts of butanol was prepared in the reaction vessel, the temperature in the reaction vessel was maintained at 110 ° C, and a mixture of the following composition such as a monomer raw material previously mixed was dropped for 3 hours.

Styrene 50 parts

2-ethylhexyl methacrylate 35 parts

Glycidyl methacrylate 15 parts

2,2'-azobisisobutyronitrile 2.0 parts

Thereafter, 0.5 part of 2,2'-azobisisobutyronitrile was further added, and the reaction was carried out at 110 ° C for 2 hours. Next, the temperature in the reaction vessel was set to 80 ° C, and 12.2 parts of orthophosphoric acid having a concentration of 85% and 10.4 parts of butanol were gradually added, and the reaction was carried out for 1 hour until the turbidity in the reaction vessel disappeared, thereby obtaining a solid content of 50%. Phosphate-based acrylic resin 1 solution. The solid content phosphate-containing acrylic resin 1 had a resin acid value of 54 (phosphate group concentration: 0.096 equivalent/100 g of resin).

Production Example 4 Production of Phosphate-Based Acrylic Resin 2 In the reaction vessel, 100 parts of butanol was prepared, and the temperature in the reaction vessel was maintained at 110 ° C, and the following composition of the pre-mixed monomer raw material or the like was dropped for 3 hours. mixture.

Styrene 53

2-ethylhexyl methacrylate 40

Glycidyl methacrylate 7

2,2'-azobisisobutyronitrile 2.0

Thereafter, 0.5 part of 2,2'-azobisisobutyronitrile was further added, and the reaction was carried out at 110 ° C for 2 hours. Next, the temperature in the reaction vessel was set to 80 ° C, and 5.7 parts of orthophosphoric acid having a concentration of 85% and 4.9 parts of butanol were gradually added, and the reaction was carried out for 1 hour until the turbidity in the reaction vessel disappeared, thereby obtaining a solid content of 50%. Phosphate-based acrylic resin 2 solution. The solid content phosphate group-containing acrylic resin 2 has a resin acid value of 26 (phosphate group concentration of 0.047 equivalent/100 g of resin).

Production Example 5 Production of Phosphate-Based Acrylic Resin 3

While 100 parts of butanol was prepared in the reaction vessel, the temperature in the reaction vessel was maintained at 110 ° C, and a mixture of the following composition such as a monomer raw material previously mixed was dropped for 3 hours.

Styrene 40 parts

2-ethylhexyl methacrylate 30 parts

Glycidyl methacrylate 30 parts

2,2'-azobisisobutyronitrile 2.0 parts

Thereafter, 0.5 part of 2,2'-azobisisobutyronitrile was further added, and the reaction was carried out at 110 ° C for 2 hours. Next, the temperature in the reaction vessel was set to 80 ° C, and 25 parts of orthophosphoric acid having a concentration of 85% and 17 parts of butanol were gradually added, and the reaction was carried out for 1 hour until the turbidity in the reaction vessel disappeared, thereby obtaining a solid content of 50%. Phosphate-based acrylic resin 3 solution. The solid content phosphate-containing acrylic resin 3 had a resin acid value of 98 (phosphate group concentration of 0.17 equivalent/100 g of resin).

Production Example 6 Production of Phosphate-Containing Epoxy Resin

100 parts of cyclohexanone and 100 parts of jER1007 (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol A type epoxy resin, hydroxyl group-containing resin) were prepared in a reaction vessel, and the mixture was stirred and heated to 70 ° C to dissolve the resin. Then, 5.76 parts of 85% orthophosphoric acid was added, and the reaction was carried out at 70 ° C for 2 hours, followed by the addition of 4 parts of cyclohexanone to obtain a 50% phosphoric acid group-containing epoxy resin solution. A solid content phosphate group-containing epoxy resin having a resin acid value of 28 (a phosphate group concentration of 0.05 equivalent/100 g of a resin).

Production Example 7 Production of Phosphate-Based Acrylic Resin

In a sturdy glass container, 100 parts (solid content: 50 parts), 50% of the solid content of the acrylic resin solution obtained in Preparation Example 3, and 5 parts of mashed calcium oxide, filled with glass beads, to Skandex (manufactured by Mitsuwa-Tech Ltd., trade name, stirrer) was dispersed until the resin solution became transparent. Next, it was allowed to stand at room temperature for 48 hours. Thereafter, the glass beads were removed to obtain a target phosphate-containing acrylic resin solution.

Manufacture of ion-exchanged cerium oxide

Production Example 8 Production of Mg ion exchange ruthenium dioxide

10 parts by mass of Sylysia, 710 (manufactured by Fuji Silysia Chemical Ltd., trade name, cerium oxide fine particles, oil absorption: about 105 ml/100 g) was stirred and mixed for 5 hours in 10,000 parts by mass of a magnesium carbonate aqueous solution having a concentration of 5 mass%. The solid component was taken out by filtration, and the solid component was carefully washed and dried to obtain Mg ion-exchanged cerium oxide.

Production Example 9 Production of Co ion-exchanged cerium oxide

10 parts by mass of Sylysia 710 (manufactured by Fuji Silysia Chemical Ltd., trade name, cerium oxide microparticles, oil absorption: about 105 ml/100 g) was stirred and mixed for 5 hours in 10,000 parts by mass of a cobalt chloride aqueous solution having a concentration of 5 mass%. The solid component was taken out by filtration, and the solid component was carefully washed and dried to obtain Co ion-exchanged cerium oxide.

Manufacture of anti-corrosive coating composition

Example 1

85 parts of jER1009 (manufactured by Japan Epoxy Resins Co., Ltd., bisphenol A type epoxy resin, hydroxyl group-containing resin) were dissolved in 135 parts of a mixed solvent 1 [cyclohexanone / ethylene glycol monobutyl ether / Solvesso 150 ( 5 parts of vanadium pentoxide, 3 parts of Shieldex AC-3 (WRGrace & 225 parts of epoxy resin solution made by Esso Petroleum Co., Ltd., high boiling point aromatic hydrocarbon solvent) = 3/1/1 (mass ratio) Co., Ltd., trade name, calcium ion exchange ruthenium dioxide), 20 parts of titanium dioxide, 20 parts of cerium oxide and an appropriate amount of mixed solvent 2 [Solvesso 150 (made by Esso Petroleum Co., Ltd., high boiling point aromatic hydrocarbon solvent) / cyclohexyl The ketone = 1/1 (mass ratio) was mixed, and the pigment was dispersed until the particles (particle diameter of the pigment coarse particles) were 20 μm or less. Next, 20 parts (solid content: 15 parts) of Desmodur BL-3175 (Sumika Bayer Urethane Co., Ltd., a solution of HDI isocyanate type polyisocyanate compound blocked with methyl ethyl ketone oxime, and a solid content were added to the dispersion. 75%), 4 parts (2 parts by weight) of the phosphoric acid group-containing acrylic resin 1 solution obtained in Production Example 3, and 2 parts of TAKENATE TK-1 (manufactured by Takeda Pharmaceutical Co., Ltd., organotin block release agent, The solid content was about 10%), and the mixed solvent 2 was added thereto, and the viscosity was adjusted to about 80 seconds (Ford Cup #4/25 ° C) to prepare a rust preventive paint composition.

Examples 2 to 20, Comparative Examples 1 to 10, and Reference Examples 1 and 2

The same experiment as in Example 1 was carried out except that the hydroxyl group-containing resin, the crosslinking agent, the rust preventive pigment, and other pigments used in Example 1 were changed as shown in Table 1 below to obtain each rust preventive paint composition. . Reference Examples 1 and 2 are rust-preventive coating compositions containing a chromate-based rust-preventive pigment. The amounts of the hydroxyl group-containing resin, the crosslinking agent, the phosphoric acid (salt)-containing resin, and the pigment component in Table 1 are all expressed by the mass of the solid component. However, in Example 15, TAKENATE TK-1 was not mixed, and in Examples 16 to 19, in place of 2 parts of TAKENATE TK-1, 1 part of NACURE 5225 (manufactured by King Industries Inc., USA, 12) was mixed. Neutralization solution of the amine of alkylbenzenesulfonic acid).

The amount of each rust preventive pigment (C) blended with the resin component (the mass of the solid component of the hydroxyl group-containing resin and the crosslinking agent is 100 parts by mass) and the amount of strontium chromate are added to 10,000 parts by mass. The pH of the filtrate (the pH of the rust preventive pigment solution) which was stirred for 6 hours at 25 ° C in a sodium chloride aqueous solution at 25 ° C and allowed to stand at 25 ° C for 48 hours. Also shown in Table 1. For example, the pH value of the rust preventive pigment solution of Example 1 is added to 5 parts by mass of a sodium chloride aqueous solution having a concentration of 5% by mass and 25 ° C, and 5 parts by mass of vanadium pentoxide and 3 parts by mass of Shieldex AC-3 are added. The pH of the filtrate in which the supernatant liquid was filtered by the above conditions was dissolved under the above conditions.

In the above Table 1, the (note) in the table each has the following meaning.

(Note 1) Epokey 837: manufactured by Mitsui Chemicals Co., Ltd., trade name, urethane-modified epoxy resin, hydroxyl-containing resin, having a primary hydroxyl group value of about 35 and an acid value of about 0.

(Note 2) Vylon 296: manufactured by Toyobo Co., Ltd., trade name, epoxy-modified polyester resin, resin containing hydroxyl group, hydroxyl group price 7, acid value 6.

(Note 3) Sumidur N3300: manufactured by Sumika Bayer Urethane Co., Ltd., isocyanate type polyisocyanate compound, and has a solid content of 100%.

(Note 4) Cymel 303: manufactured by Nihon Cytec Industries Co., Ltd., trade name, methyl etherified melamine resin.

(Note 5) Shieldex C303: manufactured by W.R. Grace & Co., trade name, calcium ion exchange cerium oxide.

(Note 6) Aerosil 200: manufactured by Nippon Aerosil Co., Ltd., trade name, cerium oxide microparticles, oil absorption of about 280 ml/100 g.

(Note 7) sandvor 3058: manufactured by Clariant, trade name, hindered amine-based UV stabilizer.

Test coating plate

Using each of the rust-preventive paint compositions and the surface coating materials obtained in the above Examples 1 to 20, Comparative Examples 1 to 10, and Reference Examples 1 and 2, each of the raw materials was coated by the following coating treatment, and calcined to obtain each Test coated plates.

Painting treatment 1:

The galvanized steel sheet with a chemical conversion treatment (thickness of 0.35 mm, aluminum-zinc alloy plated steel, alloy containing about 55% aluminum, alloy plating unit weight of 150 g/m ² , and table 2 with "GL steel sheet" In the above, the back surface coating material obtained in the above Production Example 2 was coated with a bar coater at a dry film thickness of 8 μm, and the raw material was allowed to reach a maximum temperature of 180 ° C for 30 seconds to form a back surface coating film. . Each of the rust-preventive paint compositions obtained in the above respective examples was coated with a bar coater at a dry film thickness of 5 μm on the side of the steel sheet opposite to the back coating film of the coated plate on which the back coating film was formed. The coating was carried out, and the raw materials were brought to a maximum temperature of 220 ° C for 40 seconds to form a main coating film. After cooling, the KP color 1580B40 (manufactured by Kansai Paint Co., Ltd., trade name, polyester-based surface coating, blue, and cured glass film having a glass transition temperature of about 70 ° C) was applied to the main coating film. The bar coater and the dried film were coated at a thickness of about 15 μm, and the raw materials were brought to a maximum temperature of 220 ° C for 40 seconds to prepare test plates for each test.

Painting treatment 2:

The hot-dip galvanized steel sheet having a chemical conversion treatment (thickness: 0.35 mm, zinc electroplating unit weight: 250 g/m ² , and "GI steel plate" in Table 2) was used to obtain the coating material for back surface obtained in the above Production Example 2 The dried film was coated with a bar coater at a thickness of 8 μm, and the raw material was allowed to stand at a maximum temperature of 180 ° C for 30 seconds to form a back coat film. Each of the rust-preventive paint compositions obtained in the above respective examples was coated with a bar coater at a dry film thickness of 5 μm on the side of the steel sheet opposite to the back coating film of the coated plate on which the back coating film was formed. Each of the primer coating sheets was prepared by coating and baking the raw materials to a maximum temperature of 220 ° C for 40 seconds. After cooling, KP color 1580B40 (manufactured by Kansai Paint Co., Ltd., trade name, polyester-based surface coating, blue, hardened coating film, glass transition temperature of about 70 ° C) was made on the primer coating plate. The test coating plate was prepared by coating with a bar coater and a dry film thickness of about 15 μm, and baking the raw material to a maximum temperature of 220 ° C for 40 seconds.

Painting treatment 3:

The rust-preventive coating composition obtained in Example 3 was coated with a bar coater at a dry film thickness of 8 μm on the same aluminum-zinc-zinc steel plate as that used for the coating treatment 1, and the raw material was brought to the highest temperature. The firing was carried out at 180 ° C for 30 seconds to form a back coating film. Each of the rust-preventive paint compositions obtained in the above respective examples was coated with a bar coater at a dry film thickness of 5 μm on the side of the steel sheet opposite to the back coating film of the coated plate on which the back coating film was formed. Each of the primer coating films was prepared by coating and heating the raw materials to a maximum temperature of 220 ° C for 40 seconds. After cooling, KP color 1580B40 (manufactured by Kansai Paint Co., Ltd., trade name, polyester-based surface coating, blue, hardened coating film, glass transition temperature of about 70 ° C) was made on the primer coating film. The coating plate was coated with a bar coater and a dry film thickness of about 15 μm, and the raw material was baked at a maximum temperature of 220 ° C for 40 seconds to prepare a test coated plate.

Film performance test

With respect to each of the test coated sheets obtained in the above Examples 1 to 20 and Comparative Examples 1 to 10 and Reference Examples 1 and 2, the coating film performance test was carried out by the following test method. The test results are shown in Table 2 below.

experiment method

Boiling water resistance: Each of the test coated sheets cut into a size of 5 cm × 10 cm was immersed in boiling water of about 100 ° C for 5 hours, and the appearance of the coating film on the surface side was taken out, and the evaluation of the checkerboard tape adhesion test was performed. The checkerboard tape adhesion test was based on the JIS K-5400 8.5.2 (1990) checkerboard tape method, and the gap between the cuts was 1 mm. 100 checkerboards were made, and the adhesive tape was adhered to the surface to observe the severe peeling. The number of chessboards remaining in the painted surface.

◎: There is no abnormality such as debris or whitening on the coating film, and the number of remaining checkerboards is 100.

○: There is no abnormality such as debris or whitening on the coating film, and the number of remaining checkerboards is 91 to 99.

△: There is an abnormal situation in which a small amount of chips, whitening, etc. are generated on the coating film, and the number of remaining checkerboards is 91 or more, or there is no abnormality such as fragmentation or whitening on the coating film, but the number of remaining checkerboards is 71 to 90. One

×: A rather significant fragmentation occurred on the coating film, or the number of remaining checkerboards was 70 or less.

Alkali resistance: The back surface and the cut surface of each test coated sheet cut into a size of 5 cm × 10 cm were sealed with a rust preventive paint, and a cross shape reaching the texture was cut at the center portion of the surface side of the coated sheet. After the coated plate was immersed in a 5% sodium hydroxide aqueous solution at 40 ° C for 48 hours, it was taken out and washed, and the appearance of the coating film on the surface side of the coated plate dried at room temperature was evaluated, and the adhesive tape was applied to the cross-cut portion. The adhesion was measured to evaluate the peeling width (single side) of the coating film from the cut portion after the intense peeling.

◎: No chipping occurred, and the tape peeling width from the cutting portion was 1.5 mm or less.

○: There is no chipping, and the tape peeling width from the cutting portion is larger than 1.5 mm and 3 mm or less.

△: There is a slight fragmentation, the tape peeling width from the cutting portion is 3 mm or less, or no chipping occurs, but the tape peeling width from the cutting portion is larger than 3 mm.

×: A fragmentation occurred, and the tape peeling width from the cut portion was more than 3 mm.

Acid resistance: The back surface and the cut surface of each of the test coated sheets cut into a size of 5 cm × 10 cm were sealed with a rust preventive paint, and a cross shape reaching the texture was cut at the center portion of the surface side of the coated sheet. After the coated plate was immersed in a 5% sodium hydroxide aqueous solution at 40 ° C for 48 hours, it was taken out and washed, and the appearance of the coating film on the surface side of the coated plate dried at room temperature was evaluated, and the adhesive tape was applied to the cross-cut portion. The adhesion was measured to evaluate the peeling width (single side) of the coating film from the cut portion after the intense peeling.

◎: No chipping occurred, and the tape peeling width from the cutting portion was 1.5 mm or less.

○: There is no chipping, and the tape peeling width from the cutting portion is larger than 1.5 mm and 3 mm or less.

△: There is a slight fragmentation, the tape peeling width from the cutting portion is 3 mm or less, or no chipping occurs, but the tape peeling width from the cutting portion is larger than 3 mm.

×: A fragmentation occurred, and the tape peeling width from the cut portion was more than 3 mm.

Scratch resistance: At a room temperature of 20 ° C, a coil abrasion test (manufactured by Automated Technik Co., Ltd.) was used, and the edge of the 10-round copper coin was maintained at an angle of 45 degrees on the surface of the surface of each test coated plate. A load of 3 kg was applied to attach it, and 10 round copper coins were stretched by about 30 mm at a speed of 10 mm/sec, and the degree of scratching when the surface was scratched was evaluated on the basis of the following criteria.

◎: There is no metal raw material in the scratched part.

○: There is a slight metal material in the scratched part.

△: There is a significant metal raw material in the scratched part.

×: There is almost no coating film in the scratched portion, and it is completely a metal raw material.

Composite Corrosion Resistance Test: The test piece used for the composite corrosion resistance test was produced in the following manner. Each of the test coated sheets having a size of 7 cm × 15 cm was preliminarily cut, and after the weather resistance test was conducted for 500 hours using a xenon arc lamp type weathering resistance tester, respectively, shearing was performed from 5 mm at both side edges of the long sides. The machine is cut so that the burr faces the surface side of the film surface, the right side faces the surface side, and the left side faces the back side. The center portion of the front side of the test piece reaches a narrow angle of 30 degrees and a line width of 0.5 mm. The cross-cut portion of the test piece is cut by the back of the cutter so that the end edge portion of the coating plate is sealed with an anti-rust paint, and is disposed at the upper end portion. 3T bending processing portion (the surface side of the coating plate is bent outward, and three sheets of the same thickness as the coating plate are sandwiched on the inner side thereof, and the above-mentioned coated plate is subjected to a 180-degree bending process with a vise) to prepare a test. sheet. For each of the obtained test pieces, a composite cyclic corrosion test according to JIS K-5621 (1990) was carried out. The conditions of the composite cyclic corrosion test are: (0.5 hour spray at 5% solution of 30 ° C) - (tested for 1.5 hours in a humidity tester at RH 95% or higher at 30 ° C) - (drying at 50 ° C for 2 hours) - (drying at 30 ° C for 2 hours) was one cycle, and 200 cycles (total of 1200 hours) were carried out. The state of the 3T bending portion, the edge portion, the cross-cut portion, and the flat portion of the test piece after the test was evaluated.

(3T bending portion) The evaluation was made based on the following criteria based on the total length of the rust portion in the 3T bending portion and the presence or absence of occurrence of red rust.

◎: There is no white rust, or the white rust is less than 5mm.

○: The white rust generating portion is 5 mm or more and less than 20 mm.

△: The white rust generation portion is 20 mm or more and less than 40 mm.

×: The white rust is generated in a portion of 40 mm or more, or red rust is generated.

(Edge portion) The evaluation was based on the following criteria based on the average value of the effective edge widths of the long sides of the left and right sides of the test piece and the presence or absence of occurrence of red rust.

◎: There is no red rust, and the average edge width is less than 5mm.

○: There is no occurrence of red rust, and the average value of the effective edge width is 5 mm or more and less than 10 mm.

△: There is no occurrence of red rust, and the average value of the effective edge width is 10 mm or more and less than 20 mm.

×: The average value of the effective edge width is 20 mm or more, or there is a case where red rust is generated.

(Cross-cutting portion) The corrosion state of the cross-cut portion, the ratio of the white rust exposed by the gold plating of the cutting width of 0.5 mm, and the average width of the fragments (the sum of the two sides) of the cut portion, and the presence or absence of The situation of red rust is evaluated on the basis of the following criteria.

◎: The ratio of white rust on the exposed part of the gold plating is less than 50% and the fragment width is less than 3mm.

○: The ratio of white rust on the exposed portion of the gold plating is 50% or more and the width of the shard is less than 3 mm, or the ratio of white rust on the exposed portion of the gold plating is less than 50% and the width of the shard is 3 mm or more and less than 5 mm.

△: The ratio of white rust on the exposed portion of gold plating is 50% or more and the width of the shard is 5 mm or more and less than 10 mm.

×: The ratio of white rust on the gold-plated exposed portion is 50% or more and the fragment width is 10 mm or more, or there is no occurrence of red rust.

The (planar portion) is not a corroded portion of the continuous edge, and the discontinuous and sporadic fragments located at the plane portion are evaluated on the basis of the following criteria.

◎: No fragmentation occurred

○: The diameter of the fragments is less than 2mm, and the number is less than 10

△: the chip diameter is about 2 mm or more and the number is less than 10, or the chip diameter is less than 2 mm and the number is 10 or more.

×: The chip diameter is about 2 mm or more, and the number is 10 or more.

Claims (11)

A coating composition for coating on a surface of a metal sheet subjected to chemical conversion treatment, comprising: (A) a coating film-forming resin containing no hydroxyl group and containing a hydroxyl group, and (B) a crosslinking agent, (C) a rust preventive pigment mixture, (D) a phosphate-containing resin and an organic solvent belonging to a phosphate group-containing resin and/or a phosphate group-containing resin, characterized in that the rust preventive pigment mixture (C) is a composition comprising (1) a vanadium compound of at least one of vanadium pentoxide, calcium vanadate and ammonium methylvanadate, and (2) ion-exchanged ruthenium dioxide; relative to the resin (A) and the crosslinking agent ( B) a total of 100 parts by mass of the solid component, the amount of the vanadium compound (1) is 3 to 50 parts by mass, the amount of the ion-exchanged cerium oxide (2) is 3 to 50 parts by mass, and the phosphoric acid (salt) group is contained. The total amount of the phosphate group-containing resin and the phosphate group-containing resin in the resin (D) is 1 to 30 parts by mass, and the amount of the rust preventive pigment mixture (C) is 6 to 100 parts by mass, the resin (A) The amount is 55 to 95 parts by mass, and the amount of the crosslinking agent (B) is 5 to 45 parts by mass. The coating composition of the first aspect of the invention, wherein the coating film-forming resin (A) is at least one of a hydroxyl group-containing epoxy resin and a hydroxyl group-containing polyester resin. The coating composition of claim 1 or 2, wherein the crosslinking agent (B) is at least one crosslinking agent selected from the group consisting of an amine based resin, a phenol resin, and a blockable polyisocyanate compound. The coating composition of claim 1, wherein the ion-exchanged cerium oxide (2) is calcium ion-exchanged cerium oxide, and magnesium ion-exchanged cerium oxide. And at least one of cobalt ion exchanged cerium oxide. The coating composition of claim 1, further comprising a pigment component of at least one of a coloring pigment and an extender pigment. The coating composition of claim 1, further comprising at least one of an ultraviolet absorber and an ultraviolet stabilizer. The coating composition of the first aspect of the invention, wherein the vanadium compound constituting the rust preventive pigment mixture (C) is blended with respect to 100 parts by mass of the total solid content of the resin (A) and the crosslinking agent (B). And a mixture of the respective mass parts of each pigment in the ion-exchanged cerium oxide (2), which is added to 10000 parts by mass of a 5 mass% aqueous sodium chloride solution at 25 ° C for 6 hours, and then static at 25 ° C After 48 hours, the pH of the filtrate obtained after filtering the supernatant liquid was 3-8. A coated metal sheet is formed by forming a cured coating film on a metal sheet having a chemical conversion treatment on the surface thereof by a coating composition according to any one of claims 1 to 7. A coated metal sheet having a plurality of layers of a coating film formed on a metal sheet having a chemical conversion treatment on the surface thereof, wherein a hardened coating film is formed by a coating composition according to any one of claims 1 to 7 A surface coating film is formed on the cured coating film. A coated metal sheet is formed by a coating composition according to any one of claims 1 to 7 on both sides of a metal sheet having a chemical conversion treatment. A coated metal plate having a plurality of coating films is applied on both sides of a metal plate whose surface has been subjected to chemical conversion treatment, as claimed in claims 1 to 6 A coating composition according to any one of the preceding claims, wherein a cured coating film is formed, and a surface coating film is formed on at least one of the cured coating films.