JP5529372B2 - Metal surface treatment composition - Google Patents

Description

  The present invention is a pollution-free metal surface treatment composition that can obtain a coating having excellent corrosion resistance instead of conventional chromate treatment and phosphate treatment, and has excellent storage stability, and the metal surface treatment composition The present invention relates to a metal plate using an object.

  Conventionally, chromate treatment and phosphate treatment are generally performed to improve the corrosion resistance of metal surfaces. However, the surface treatment method using chromate is a problem of scattering of chromate fume in the treatment process, a large amount of cost for waste water treatment equipment, and a problem due to elution of chromic acid from the chemical conversion treatment film. and so on. In addition, hexavalent chromium compounds have been designated as carcinogenic substances for the human body by many public institutions including IARC (International Agency for Research on Cancer Review).

  Also, in phosphate treatment, zinc phosphate and iron phosphate surface treatments are usually performed, but in order to provide corrosion resistance, chrome treatment is usually performed after phosphating for rinsing with chromic acid. In addition to the above problems, there are problems such as a reaction accelerator in the phosphate treatment agent, wastewater treatment of metal ions, and sludge treatment by elution of metal ions from the metal to be treated.

  As a treatment method other than the chromate treatment and the zinc phosphate treatment, (1) a surface treatment method (see Patent Document 1) of heating at a temperature of 150 to 550 ° C. after treatment with an aqueous solution containing aluminum biphosphate. (2) A method of treating with an aqueous solution containing tannic acid (see Patent Document 2) has been proposed, and (3) A method of treating with sodium nitrite, sodium borate, imidazole, aromatic carboxylic acid, surfactant, etc. Or the processing method which combined these is performed.

  However, in the method (1), when a paint is applied thereon, the adhesion of the paint is not sufficient, the method (2) is inferior in corrosion resistance, and the methods (3) are both high temperatures. There is a problem that the corrosion resistance is inferior when exposed to a humid atmosphere.

  In addition, as a zinc-based steel sheet having a thin film with a film thickness of several μm or less, Patent Document 3, Patent Document 4, Patent Document 5 and the like use a zinc-based plated steel sheet as a base material, and form a chromate film on this. Further, a rust-proof steel sheet having an organic composite silicate film formed thereon as an uppermost layer is known, and this has excellent workability and corrosion resistance. However, since this rust-proof steel plate has a chromate film, there was a problem of health and safety due to chromate ions as described above. Moreover, the steel plate obtained by removing the chromate film from the rust-proof steel plate still has insufficient corrosion resistance.

  As a non-chromium surface treatment agent, Patent Document 6 discloses an invention relating to a surface treatment agent containing an anionic polyurethane resin, a silane coupling agent, and a water-soluble Zr compound. Patent Document 7 discloses an invention relating to a surface treatment agent for a precoat metal material containing a silane coupling agent, a cationic polyurethane resin, a Zr compound and / or a Ti compound, and a fluorine-containing inorganic compound. However, these surface treatment agents do not necessarily have sufficient corrosion resistance of the resulting film, and depending on the selected species of the rust preventive component, the mixing stability is poor and the storage stability of the surface treatment agent can be obtained. Absent.

Japanese Patent Publication No.53-28857 JP-A-51-71233 JP 58-224174 A JP 60-50179 A Japanese Patent Laid-Open No. 60-50180 JP 2004-204333 A JP 2006-328445 A

  An object of the present invention is a pollution-free surface treatment composition having corrosion resistance comparable to chromate treatment and phosphate treatment and having excellent storage stability, fingerprint resistance, solvent resistance, and top coat adhesion. Is to provide.

The present invention relates to (A) an epoxy prepolymer (I) having a secondary amino group obtained by reacting a polyepoxy compound (a) with an amine compound (b) containing a polyoxyalkyleneamine as at least a part of its components. And a compound (c) containing two or more hydroxyl groups in one molecule containing a polyol having a polyoxyalkylene chain serving as a side chain as at least a part of the component, and a polyisocyanate compound (d) and active in one molecule. A polyurethane resin obtained by a reaction with a urethane prepolymer (II) having an isocyanate group obtained by a reaction with a compound (e) containing two or more hydrogen groups and a tertiary amino group , both epoxy prepolymer (I) and the urethane prepolymer (II) having a polyoxyalkylene chain in a side chain An aqueous dispersion of a polyurethane resin, and (B) at least one selected from a phosphoric acid compound, a vanadium compound, a zirconium compound, a titanium compound, a cobalt compound, a nickel compound, a silane coupling agent, and silica particles, To a metal surface treatment composition.
Moreover, this invention relates to the metal plate formed by apply | coating the said metal surface treatment composition to a steel plate, and forming a film.

  According to the present invention, a polyurethane resin obtained by a reaction between a specific epoxy prepolymer and a urethane prepolymer, and using an aqueous dispersion of a polyurethane resin having a polyalkyleneoxy chain in the side chain of the polyurethane resin, Regardless of whether the rust inhibitor is acidic or basic, a metal surface treatment composition having excellent storage stability can be obtained, and further has corrosion resistance comparable to chromate treatment and phosphate treatment, and It is possible to form a film excellent in fingerprint resistance, solvent resistance, and top coat adhesion.

  The metal surface treatment composition of the present invention comprises an epoxy prepolymer (I) having a secondary amino group obtained by reaction of a polyepoxy compound (a) and an amine compound (b), and two hydroxyl groups in one molecule. A polyurethane resin obtained by a reaction with a urethane prepolymer (II) having an isocyanate group obtained by a reaction between the compound (c) and the polyisocyanate compound (d), comprising the epoxy prepolymer (I) and Both or one of the urethane prepolymers (II) contains an aqueous dispersion (A) of a polyurethane resin having a polyoxyalkylene chain in the side chain.

  In the present invention, the epoxy prepolymer (I) has a secondary amino group and is obtained by a reaction between the polyepoxy compound (a) and the amine compound (b).

  The polyepoxy compound (a) is a compound having two or more epoxy groups in one molecule, such as bisphenol A, bisphenol F, bisphenol S, hydrogenated bisphenol A, neopentyl glycol, 1,6-hexanediol, etc. Diglycidyl ethers of polyhydric alcohols; glycidyl ether type epoxy resins such as bisphenol A and bisphenol F, hydrogenated bisphenol A type epoxy resins, glycidyl ester type epoxy resins, alicyclic epoxy resins, polyglycol type epoxy resins; A modified epoxy resin obtained by modifying an epoxy resin with at least one modifier selected from alkylphenols and fatty acids; obtained by reacting an alkylphenol or an alkylphenol novolac resin with epichlorohydrin Epoxy group-introduced alkylphenol or alkylphenol novolak type resins; dibasic acid modified epoxy resins, and the like modified epoxy resin dibasic acid and a carboxyl group-containing phenol.

  The amine compound (b) is a compound having a primary amino group, for example, an aliphatic amine such as propylamine, isopropylamine, butylamine, amylamine, hexylamine, octylamine, decylamine, undecylamine, dodecylamine; Aromatic amines such as aniline, o-toluidine, m-toluidine, and p-toluidine; cycloaliphatic amines such as cyclobutylamine, cyclopentylamine, and cyclohexylamine; and methylaminopropylamine and the like. Can do. Further, as the amine compound (b), an alkanolamine can be used when a highly reactive active hydrogen group is left in the polyurethane resin. Examples of the alkanolamine include monoethanolamine and monoisopropanolamine. N-methylethanolamine, N-ethylethanolamine, N-benzylethanolamine, diethanolamine, diisopropanolamine and the like can be used in combination with these as required. Furthermore, aminosilane can be used as the amine compound (b) from the viewpoint of improving the water resistance of the formed film. The aminosilane contains an amino group and an alkoxysilyl group in one molecule, and specific examples thereof include, for example, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-aminopropylmethyldisilane. Examples include ethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) aminopropyltrimethoxysilane, and N-β- (aminoethyl) aminopropyltriethoxysilane.

  In the present invention, when the polyoxyalkylene chain is added to the side chain of the epoxy prepolymer (I), a polyoxyalkyleneamine can be used as the amine compound (b). The polyoxyalkyleneamine is not particularly limited as long as it is a compound having a primary amino group and further having a polyoxyalkylene chain, and various compounds can be used. Examples of the polyoxyalkylene chain include a polyoxyethylene chain, a polyoxypropylene chain, a block chain of polyoxyethylene and polyoxypropylene, and the like. The polyoxyalkylene chain preferably has a molecular weight in the range of 100 to 10,000, particularly 200 to 8,000.

  Representative examples of the polyoxyalkyleneamine include, for example, the following general formula (1)

（式中、Ｒ¹は水酸基又は炭素数１〜４のアルコキシ基を表し、Ｒ²は水素原子又はメチル基を表し、ｍは２〜２２０、好ましくは５〜１８０の整数であり、ｎは２〜３の整数、好ましくは２である、ここでｍ個のオキシアルキレン単位（Ｃ_ｎＨ_2ｎＯ）は同じであっても又は互に異なっていてもよい。）で示される化合物を挙げることができる。アミン化合物（ｂ）成分の少なくとも一部としてポリオキシアルキレンアミンを用いることは、本発明の金属表面処理組成物の貯蔵安定性の点で好ましい。

(Wherein R ¹ represents a hydroxyl group or an alkoxy group having 1 to 4 carbon atoms, R ² represents a hydrogen atom or a methyl group, m is an integer of 2 to 220, preferably 5 to 180, and n is 2) An integer of ˜3, preferably 2, where m oxyalkylene units (C _n H _2n O) may be the same or different from each other). it can. The use of polyoxyalkyleneamine as at least a part of the amine compound (b) component is preferable from the viewpoint of storage stability of the metal surface treatment composition of the present invention.

  The proportion of polyoxyalkyleneamine used is not particularly limited. The proportion of use is preferably such that the content of polyoxyalkyleneamine in the polyurethane resin is 1 to 50% by weight, more preferably 5 to 30% by weight. These ranges are significant in terms of storage stability and water resistance.

  These amine compounds (b) can be used alone or in combination of two or more.

  The production of the epoxy prepolymer (I) is not particularly limited, and a conventionally known method can be adopted, and it is usually performed by heating at 50 to 250 ° C. for 1 to 24 hours. The proportions of the components (a) and (b) can be variously changed, but the equivalent ratio of the epoxy group in the component (a) and the amino group in the component (b) is generally 1: 0.5 to 1 : 2, preferably 1: 0.5 to 1: 0.9.

  In the present invention, the urethane prepolymer (II) is obtained by reacting a compound (c) having an isocyanate group and containing two or more hydroxyl groups in one molecule with the polyisocyanate compound (d).

  A compound (c) containing two or more hydroxyl groups in one molecule (hereinafter sometimes abbreviated as “compound (c)”) has two or more hydroxyl groups in one molecule. Examples include glycols, high molecular weight glycols, polyester polyols, and polycarbonate polyols. These may be used alone or in combination of two or more. For example, low molecular weight glycol can be used in combination with polyester polyol or high molecular weight glycol. .

  Examples of the low molecular weight glycols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, tetramethylene glycol, hexamethylene glycol, decamethylene glycol, octanediol, and tricyclodecanedi. There are methylol, cyclohexanedimethanol, hydrogenated bisphenol A and the like, and these can be used alone or in combination of two or more.

  Examples of the high molecular weight glycols include polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and polycarbonate glycol. Polyester polyols include those obtained by reacting a glycol component with a dicarboxylic acid component. It can manufacture easily by this, and it can manufacture not only by esterification but also by transesterification. Moreover, the polyester diol obtained by ring-opening reaction of cyclic ester compounds, such as (epsilon) -caprolactone, and these cocondensation polyesters can also be included.

  The compound (c) can contain a bisphenol skeleton-containing diol compound as at least a part of its components from the viewpoint of improving the corrosion resistance of the formed film.

  Examples of the bisphenol skeleton-containing diol compound include ethylene oxide and / or propylene oxide adducts of bisphenols. Examples of bisphenols include bisphenol A, bisphenol F, and bisphenol S.

  When the bisphenol skeleton-containing diol compound is used, the content in the compound (c) is 10 to 98% by weight, preferably 50 to 95% by weight.

  In the present invention, when the side chain of the urethane prepolymer (II) has a polyoxyalkylene chain, the compound (c) contains a polyol having a polyoxyalkylene chain as a side chain as at least a part of its components. Is preferred.

  The polyol having a polyoxyalkylene chain as a side chain is a compound having two or more hydroxyl groups in one molecule and further having a polyoxyalkylene chain, and the side chain when incorporated into a urethane prepolymer. Various compounds can be used without particular limitation as long as a polyoxyalkylene chain can be introduced into the portion. Examples of the polyoxyalkylene chain include a polyoxyethylene chain, a polyoxypropylene chain, a block chain of polyoxyethylene and polyoxypropylene, and the like. The polyoxyalkylene chain preferably has a molecular weight in the range of 100 to 10,000, particularly 200 to 8,000.

  Specific examples of the polyol having a polyoxyalkylene chain as a side chain include, for example, a reaction product of an acrylate having a polyoxyalkylene chain and a dialkanolamine, a reaction product of glycerol carbonate and a polyoxyalkyleneamine, and the like. Further, it may be a reaction product of glycidol and polyoxyalkyleneamine.

  As an acrylate having a polyoxyalkylene chain, for example, the following formula (2)

（式中、Ｒ^３は水素原子又は炭素数１〜４のアルキル基を表し、ｍは２〜２２０、好ましくは５〜１８０の整数であり、ｎは２〜３の整数、好ましくは２である、ここでｍ個のオキシアルキレン単位（Ｃ_ｎＨ_2ｎＯ）は同じであっても又は互に異なっていてもよい。）で示される化合物を挙げることができる。その具体例としては、例えば、メトキシポリエチレングリコールアクリレート、エトキシポリエチレングリコールアクリレートなどを挙げることができる。

(In the formula, R ³ represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, m is an integer of 2 to 220, preferably 5 to 180, and n is an integer of 2 to 3, preferably 2. And m oxyalkylene units (C _n H _2n O) may be the same or different from each other). Specific examples thereof include methoxy polyethylene glycol acrylate and ethoxy polyethylene glycol acrylate.

  Examples of dialkanolamines include diethanolamine and dipropanolamine.

  The acrylate having a polyoxyalkylene chain and the dialkanolamine have a molar ratio of acrylate to amino group of 1: 0.8 to 1: 1.2, preferably 1: 0.95 to 1: 1.05. It is desirable to make it react so that. This reaction is usually performed at a temperature of 25 to 250 ° C, preferably 50 to 160 ° C.

  As said polyoxyalkylene amine, the thing similar to the polyoxyalkylene amine demonstrated in the above-mentioned amine compound (b) can be selected suitably, and can be used. Glycerin carbonate and polyoxyalkyleneamine have a molar ratio of cyclic carbonate group in glycerin carbonate to amino group in polyoxyalkyleneamine of 1: 0.8 to 1: 1.2, preferably 1: 0.95. It is desirable to make it react so that it may become the range of -1: 1.05. This reaction is usually performed at a temperature of 25 to 250 ° C, preferably 50 to 160 ° C.

  The ratio of the polyol having a polyoxyalkylene chain as a side chain is not particularly limited. The proportion of use is preferably such that the content of the polyol having a polyoxyalkylene chain as a side chain in the polyurethane resin is 1 to 50% by weight, more preferably 5 to 30% by weight. These ranges are significant in terms of storage stability and water resistance.

  The polyisocyanate compound (d) (hereinafter sometimes abbreviated as “compound (d)”) contains two or more isocyanate groups in one molecule. Specific examples thereof include hexamethylene diisocyanate. Aliphatic polyisocyanates such as trimethylhexamethylene diisocyanate, dimer acid diisocyanate, lysine diisocyanate; burette-type adducts, isocyanurate cycloadducts of these polyisocyanates; isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate) Methylcyclohexane-2,4- (or-2,6-) diisocyanate, 1,3- (or 1,4-) di (isocyanatomethyl) cyclohexane, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane Cycloaliphatic diisocyanates such as lanthanum diisocyanate and 1,2-cyclohexane diisocyanate; bullet type adducts and isocyanurate cycloadducts of these diisocyanates; xylylene diisocyanate, metaxylylene diisocyanate, tetramethyl xylylene diisocyanate , Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-naphthalene diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether isocyanate, (m- Or p-) phenylene diisocyanate, 4,4′-biphenylene diisocyanate, 3,3′-dimethyl-4,4′-biphenylene diisocyanate, bis (4-isocyana) Aromatic diisocyanate compounds such as phenyl) sulfone and isopropylidenebis (4-phenylisocyanate); Burette type adducts, isocyanurate cycloadducts of these diisocyanate compounds; triphenylmethane-4,4 ′, 4 '' -Triisocyanate, 1,3,5-triisocyanatobenzene, 2,4,6-triisocyanatotoluene, 4,4′-dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate, etc. Polyisocyanates having three or more isocyanate groups in one molecule; burette type adducts, isocyanurate cycloadducts of these polyisocyanates; ethylene glycol, propylene glycol, 1,4-butylene glycol, dimethylolpropionic acid , Polyalkylene grease Urethane adducts obtained by reacting a polyisocyanate compound in an excess ratio of isocyanate groups to the hydroxyl groups of polyols such as coal, trimethylolpropane, hexanetriol; burette type adducts of these urethanized adducts And isocyanurate cycloadducts.

  In the present invention, the compound (d) also contains a polyisocyanate having a polyoxyalkylene chain as a side chain as at least a part of the component, so that the polyoxyalkylene chain is added to the side chain of the urethane prepolymer (II). It is possible to have it. The polyisocyanate having a polyoxyalkylene chain as a side chain is, for example, a compound having two or more isocyanate groups in one molecule and further having a polyoxyalkylene chain, which is incorporated into a urethane prepolymer. Any compound can be used without particular limitation as long as it can introduce a polyoxyalkylene chain into the side chain.

  In the present invention, when the urethane prepolymer (II) contains a tertiary amino group, a compound (e) containing two or more active hydrogen groups in one molecule and containing a tertiary amino group is produced. It can be used as a raw material.

  The compound (e) preferably contains two or more active hydrogen groups in one molecule and a tertiary amino group. For example, a diol compound, a triol compound, or a diamine compound having a tertiary amino group. And triamine compounds. These may be used alone or in combination of two or more. Examples of the diol compound having a tertiary amino group include N-methyldiethanolamine, N-ethyldiethanolamine, and N-isobutyldiethanolamine. Examples of the triol compound having a tertiary amino group include triethanolamine. . Examples of the triamine compound having a tertiary amino group include methyliminobispropylamine and butyliminobispropylamine.

  Production of the urethane prepolymer (II) is not particularly limited, and a conventionally known method can be employed. For example, the above-described components (c) and (d) (component (e) as required) are reacted at once. You may make it react, and you may make it react in multistage. The proportions of the above components (c) and (d) (component (e) as required) can be varied, but the equivalent ratio of isocyanate groups to active hydrogen groups in all components is generally 1: 0. It is desirable that the ratio is 9 to 1: 0.5, preferably 1: 0.9 to 1: 0.7. The reaction is usually carried out at a temperature of 40 to 180 ° C, preferably 60 to 130 ° C. In order to promote this reaction, amine catalysts such as triethylamine, N-ethylmorpholine, and triethylenediamine used in ordinary urethanization reactions and tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate are used as necessary. It may be used.

  The polyurethane resin of the present invention is obtained by a reaction between the epoxy prepolymer (I) and the urethane prepolymer (II).

  The reaction between the epoxy prepolymer (I) and the urethane prepolymer (II) is not particularly limited, and a conventionally known method can be adopted. Is called. The use ratio of the two can be variously changed, but the equivalent ratio of the secondary amino group in the epoxy prepolymer (I) and the isocyanate group in the urethane prepolymer (II) is 0.01: 1 to 0.9: It is desirable to select 1 and preferably 0.2: 1 to 0.8: 1.

  The polyurethane resin of the present invention preferably contains a cationic group. The inclusion of the cationic group is significant in terms of improving the dispersion stability of the aqueous dispersion (A) of the polyurethane resin of the present invention and further improving the storage stability of the metal surface treatment composition. The cationic group can be obtained, for example, by containing a tertiary amino group in a polyurethane resin and neutralizing part or all of the tertiary amino group with an acid or quaternizing with a quaternizing agent. it can. Neutralization with an acid may be performed by adding an acid to the aqueous medium when the polyurethane resin is dispersed in the aqueous medium, or may be performed before the polyurethane resin is dispersed in the aqueous medium.

  Examples of the acid used for the neutralization include formic acid, acetic acid, lactic acid, and phosphoric acid.

  Examples of the quaternizing agent include epoxy compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide and epichlorohydrin, sulfates such as dimethyl sulfate, diethyl sulfate and methyl paratoluenesulfonate, methyl chloride, and ethyl. Examples thereof include alkyl halides such as chloride, benzyl chloride, methyl bromide, and ethyl bromide.

  Examples of the method of allowing the polyurethane resin to contain a tertiary amino group include a method of containing a tertiary amino group in at least one of the epoxy prepolymer (I) and the urethane prepolymer (II). The epoxy prepolymer (I) is allowed to contain a tertiary amino group by appropriately selecting the use ratio of the polyepoxy compound (a) and the amine compound (b) in the production of the epoxy prepolymer (I). The method of producing | generating a secondary amino group is mentioned. Moreover, as a method of making a urethane prepolymer (II) contain a tertiary amino group, the method of using the said compound (e) as a manufacturing raw material in manufacture of the said urethane prepolymer (II) as mentioned above is mentioned.

  The aqueous dispersion (A) of the polyurethane resin of the present invention can be obtained by dispersing the polyurethane resin obtained as described above in an aqueous medium. Examples of the aqueous medium include water or a water-organic solvent mixed solution obtained by dissolving water or an organic solvent such as a water-soluble organic solvent. Dispersion in an aqueous medium can be carried out by a conventionally known method without any particular limitation.

  The aqueous dispersion (A) of the polyurethane resin of the present invention is an aqueous dispersion obtained by neutralizing part or all of the tertiary amino groups in the polyurethane resin with an acid or quaternizing with a quaternizing agent. It can be obtained by dispersing in a medium and at the same time with the dispersion by partially proceeding with a chain extension reaction with an aqueous medium, and further by subjecting it to a chain extension reaction with a chain extender to increase the molecular weight. Examples of the chain extender include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, polyoxyethylenediamine, polyoxypropylenediamine, amine-terminated polyoxyethylene-polyoxypropylene copolymer; diethylenetriamine, dipropylenetriamine, tri Polyamines such as ethylenetetramine and tetraethylenepentamine; hydroxyethylhydrazine, hydroxyethyldiethylenetriamine, 2-[(2-aminoethyl) amino] ethanol, 3-aminopropanedio Compounds having an amino group and a hydroxyl group, such as Le; hydrazines, acid hydrazides, and the like. These may be used singly or in combination.

  The polyurethane resin has an amine value of 5 to 100 mgKOH / g, preferably 8 to 90 mgKOH / g, from the viewpoint of the corrosion resistance of the formed film. Further, the polyurethane resin preferably has a hydroxyl value of 20 to 200 mgKOH / g, preferably 30 to 150 mgKOH / g, from the viewpoints of adhesion of the formed film, corrosion resistance, and the like.

  The metal surface treatment composition of the present invention comprises at least one selected from a phosphoric acid compound, a vanadium compound, a zirconium compound, a titanium compound, a cobalt compound, a nickel compound, a silane coupling agent, and silica particles (hereinafter referred to as “component ( B) "may be abbreviated.

  The compounding quantity of a component (B) is 0.1-900 weight part with respect to 100 weight part of solid content of the said polyurethane resin, Preferably it is 100-500 weight part. These ranges are significant in terms of corrosion resistance, top coat adhesion, and economy.

  A phosphoric acid compound has the effect | action which etches the zinc of a galvanized steel plate. Examples of the phosphoric acid compound include phosphoric acid, strong phosphoric acid, triphosphoric acid, hypophosphoric acid, hypophosphoric acid, trimetaphosphoric acid, diphosphoric acid, diphosphoric acid, pyrophosphoric acid, pyrophosphoric acid, metaモ ノ Monophosphoric acids such as phosphoric acid, metaphosphoric acid, phosphoric acid (orthophosphoric acid), and phosphoric acid derivatives and salts thereof, condensed phosphoric acid such as tripolyphosphoric acid, tetraphosphoric acid, hexaphosphoric acid, and condensed phosphoric acid derivatives, and salts thereof Etc. Moreover, as an alkali compound which forms above-mentioned salt, organic or inorganic alkali compounds, such as lithium, sodium, potassium, ammonium, are mentioned, for example. Further, it is preferable to use a phosphate compound that is soluble in water.

  Examples of phosphoric acid compounds include phosphoric acid, zinc phosphate, magnesium phosphate, aluminum phosphate, calcium phosphate, manganese phosphate, zinc phosphite, aluminum dihydrogen phosphate, zinc tripolyphosphate, and the like. It is preferable to use this because it exhibits an excellent effect on the corrosion resistance of the film.

  The compounding quantity of a phosphoric acid compound is not specifically limited. For example, the amount is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of storage stability.

  A vanadium compound has the effect of passivating the steel plate surface and improving the corrosion resistance. Examples of vanadium compounds include vanadium oxide, vanadic acid, lithium orthovanadate, sodium orthovanadate, lithium metavanadate, potassium metavanadate, sodium metavanadate, ammonium metavanadate, sodium pyrovanadate, vanadyl chloride, vanadyl sulfate, and the like. Can be mentioned.

  The compounding quantity of a vanadium compound is not specifically limited. For example, the amount is preferably 0.1 to 50 parts by weight, more preferably 0.5 to 20 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of corrosion resistance.

  Zirconium compounds have the effect of improving the water resistance and alkali resistance of the coating. Zirconium compounds include, for example, zirconium oxide, zirconium hydroxide, zirconium nitrate, zirconium acetate, zirconium carbonate ammonium, zirconium hydrofluoric acid, zirconium ammonium fluoride, zirconium sodium fluoride, zirconium potassium fluoride, zirconium lithium fluoride, Examples include zirconium fluoride. Of these, ammonium zirconium fluoride is preferable from the viewpoint of storage stability.

  The compounding quantity of a zirconium compound is not specifically limited. For example, the amount is preferably 0.1 to 50 parts by weight, more preferably 3 to 20 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of storage stability.

  Titanium compounds have the effect of improving corrosion resistance and alkali resistance. Examples of the titanium compound include titanium hydrofluoric acid, titanium ammonium fluoride, titanium potassium oxalate, titanium sulfate, titanium chloride, titanium isopropoxide, isopropyl titanate, titanium ethoxide, titanium 2-ethyl-1-hexanolate, and titanium. Examples include tetraisopropyl acid, tetra-n-butyl titanate, potassium potassium fluoride, sodium titanium fluoride, and the like.

  The compounding quantity of a titanium compound is not specifically limited. For example, it is preferably 0.1 to 50 parts by weight, more preferably 5 to 25 parts by weight, based on 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of alkali resistance.

  A cobalt compound has the effect | action which reduces a steel plate. Examples of the cobalt compound include cobalt sulfate, cobalt nitrate, and cobalt carbonate.

  The compounding quantity of a cobalt compound is not specifically limited. For example, the amount is preferably 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of corrosion resistance.

  The nickel compound is effective in preventing oxidation of the steel sheet. Examples of the nickel compound include nickel nitrate, nickel carbonate, nickel chloride, nickel phosphate, nickel hydroxide, and the like.

  The compounding quantity of a nickel compound is not specifically limited. For example, it is preferably 0.01 to 1 part by weight, more preferably 0.05 to 0.5 part by weight, based on 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of preventing discoloration of the steel sheet.

  The silane coupling agent is effective in improving the adhesion of the film to the steel plate. Examples of the silane coupling agent include γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, N-β ( Aminoethyl) Amino group-containing silane coupling agent such as γ-aminopropylmethyldimethoxysilane; Glycidyl group-containing silane coupling agent such as γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldimethoxysilane; -Mercapto group-containing silane coupling agent such as mercaptopropyltrimethoxysilane; Vinyl group-containing silane coupling agent such as vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (methoxyethoxy) silane; γ- (meth) acryloyloxypropi Trimethoxysilane, .gamma. (meth) acryloyloxy propyl triethoxysilane, .gamma. (meth) acryloyloxy propyl, such as dimethoxymethyl silane (meth) acryloyl group-containing silane coupling agent.

  The compounding quantity of a silane coupling agent is not specifically limited. For example, the amount is preferably 1 to 70 parts by weight, more preferably 20 to 60 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. The lower limit of these ranges is significant in terms of adhesion. Moreover, the upper limit of these ranges is significant in terms of storage stability and economy.

  Silica particles are effective in improving corrosion resistance, and are further effective in increasing the hardness of the film. As the silica particles, both colloidal silica (water dispersion type) and fumed silica (vapor phase silica) can be used. Examples of commercially available colloidal silica include Snowtex C, Snowtex N, Snowtex O (all manufactured by Nissan Chemical Industries), Adelite AT-20A, and AT-20N (all manufactured by ADEKA). Examples of commercially available fumed silica include hydrophobic silica AEROSIL R-811 and hydrophilic silica AEROSIL 200V (both manufactured by Nippon Aerosil Co., Ltd.). These are used alone or in combination of two or more. can do. The average particle size (primary particle size) of the silica particles is 5 to 100 nm, preferably 10 to 50 nm from the viewpoint of the stability of the dispersion.

  The compounding quantity of a silica particle is not specifically limited. For example, the amount is preferably 1 to 60 parts by weight, more preferably 10 to 40 parts by weight with respect to 100 parts by weight of the solid content of the polyurethane resin. These ranges are significant in terms of corrosion resistance and storage stability.

  These components (B) can be used alone or in combination of two or more.

  Moreover, the metal surface treatment composition of this invention can contain a hardening | curing agent. By adding a curing agent, a dense barrier film can be formed and the corrosion resistance and hardness can be further improved.

  The curing agent is not particularly limited, and examples thereof include an epoxy group-containing compound, a blocked polyisocyanate compound, an amino resin, an oxazoline group-containing compound, a carbodiimide, a resol type phenol resin, and polyethyleneimine.

  The compounding quantity of a hardening | curing agent is not specifically limited. Preferably it is the range of 1-50 weight part with respect to 100 weight part of solid content of a polyurethane resin, More preferably, it is the range of 3-20 weight part. The lower limits of these ranges are significant in terms of adhesion and corrosion resistance. Further, the upper limit of these ranges is significant in terms of workability.

  The addition method of a hardening | curing agent is not specifically limited, It can add by a conventionally well-known method. For example, in the case of a water-soluble curing agent, it can be added directly to an aqueous medium. Further, in the case of a hardly water-soluble or water-insoluble curing agent, an addition method of mixing the polyurethane resin with the polyurethane resin before dispersing the polyurethane resin in the aqueous medium in the production of the aqueous dispersion (A) of the polyurethane resin can be taken. .

  The polyurethane resin of the present invention is sufficiently crosslinked by the addition of the curing agent as described above, but a known curing accelerating catalyst can be used in order to further increase the low temperature crosslinking property. Examples of the curing accelerating catalyst include N-ethylmorpholine, dibutyltin dilaurate, cobalt naphthenate, stannous chloride, zinc naphthenate, and bismuth nitrate.

  Moreover, the metal surface treatment composition of the present invention may contain a lubricating function-imparting agent. The lubrication function-imparting agent only needs to impart lubricity to the resulting film. Specifically, for example, fluororesin fine powder (for example, tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoroethylene- Fine particles of ethylene copolymer resin, ethylene trifluoride chloride resin, vinylidene fluoride resin, etc.), polyolefin wax (eg, polyethylene wax, polypropylene wax, etc.), polyolefin and fluororesin are mixed in one particle Lubricants, graphite, boron nitride, carbon fluoride and the like, which can be used alone or in combination of two or more.

  The average particle diameter of the lubricating function-imparting agent is preferably 0.3 to 5.0 μm, more preferably 0.5 to 3.0 μm. When the average particle size of the lubrication function-imparting agent becomes smaller, the effect of improving the lubricity tends to decrease, and when the average particle size becomes too large, the protruding portion from the film increases, and the lubrication function-imparting agent in continuous processing. Peels off, and the problem of being easily attached to the mold arises.

  For the metal surface treatment composition of the present invention, if necessary, for example, in addition to the above-described components, thickeners, repellency inhibitors, antifoaming agents, surfactants, oxidizing agents, antibacterial agents, and coloring pigments. , Extender pigments, rust preventive pigments, conductive pigments and the like.

  Moreover, you may add hydrophilic solvents, such as methanol, ethanol, isopropanol, an ethylene glycol type, a propylene glycol type, to the metal surface treatment composition of this invention as needed.

  The metal surface treatment composition of the present invention can omit the conventional chromate treatment step, and is applied directly to a plated steel sheet such as an untreated cold-rolled steel sheet or aluminum sheet, or an untreated zinc-based plated steel sheet or an aluminum-plated steel sheet. By drying, a metal plate having excellent corrosion resistance and the like can be obtained. In addition, even if the metal surface treatment composition of the present invention is applied to a chromate-treated steel plate, there is no problem in performance, and a metal plate with better corrosion resistance can be obtained, so that it can be used as necessary. it can.

  Examples of the galvanized steel sheet include an electrogalvanized steel sheet, a hot dip galvanized steel sheet, a nickel-zinc alloy plated steel sheet, and a zinc-aluminum alloy plated steel sheet. As the zinc-aluminum plated steel sheet, in the case of zinc base, 5% Al-Zn series, 8% Al-Zn series, 15% Al-Zn series, etc., and as the aluminum base, 55% Al-Zn series, 75, etc. % Al—Zn-based materials are known, but the metal surface treatment composition of the present invention is applicable not only to these materials but also to composite plated steel sheets whose plating layers are mainly composed of aluminum and zinc. For example, an Al—Zn alloy to which Mg, Mn, Si, Ti, Ni, Co, Pb, Sn, Cr, rare metals (La, Ce, Y, Nb, etc.), etc. are added is also applicable.

The metal surface treatment composition of the present invention is used by being applied to the steel sheet, and the coating amount is preferably in the range of 0.1 to 3.0 g / m ² in terms of dry film weight, 0.5 to 2.0 g. / M ² is more preferable. When the film is thinned, the corrosion resistance, black discoloration resistance and lubricity are lowered. When the film is thickened, the corrosion resistance is improved but the press workability is lowered, and the cost is increased.

Further, it if you want to grant a proper weld metal surface treatment composition of the present invention in the steel sheet coated to a dry coating weight of 1.2 g / ^{m 2} or less, particularly about 0.3 to 0.7 g / ^{m 2} Is desirable. When the coating amount is large, dust is likely to be generated during spot welding, and the welding strength is insufficient.

  In applying the metal surface treatment composition of the present invention to a steel sheet to form a film, the viscosity of the composition is appropriately adjusted to about 5 to 30 centipoise depending on the coating amount with a diluent such as water, and then roll coater coating, It is preferable that the steel sheet is dried for 3 to 60 seconds within a range of 50 to 180 ° C. within the maximum temperature (PMT) of the steel sheet after coating so as to have a predetermined film weight by a generally known method such as spray coating or dipping coating. Thus, the steel plate excellent in corrosion resistance etc. is manufactured by coating and drying a metal surface treatment composition.

  The use of the metal plate of the present invention can be used without particular limitation for uses such as building materials, home appliances, automobiles, cans, and pre-coated steel plates, with no particular restrictions. A top coat or the like is appropriately applied. The coating method may be appropriately selected depending on the application, the shape of the object to be coated, etc. For example, spray coating, brush coating, electrodeposition coating, roll coating, curtain flow coating, etc. are preferably used. A film can be laminated instead of painting.

  Hereinafter, the present invention will be described in more detail with reference to examples. “Part” and “%” indicate “part by weight” and “% by weight” unless otherwise specified.

Synthesis Example 1 (Synthesis of polyurethane resin aqueous dispersion A-1)
Preparation of epoxy prepolymer (I-1) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, in which a bisphenol A type epoxy resin (126 g) having an epoxy equivalent of 450 g / eq, Dissolved in propylene glycol monopropyl ether (54.91 g), “Jephamine M-2070” (trade name, manufactured by Huntsman, compound contained in the structure represented by the general formula (1), R ¹ is a methoxy group , Block chain of polyoxyethylene and polyoxypropylene, number average molecular weight of about 2000) (140 g) was added, reacted at 90 ° C. for 3 hours, monoethanolamine (8.55 g) was added, and 3 at 90 ° C. The reaction was continued for a period of time until the epoxy group and amino group content (Note 1) reached about 0.762 to 0.767 mmol / g. Thereafter, methyl ethyl ketone (219.6 g) was added to obtain an epoxy prepolymer (I-1) solution. The resulting epoxy prepolymer (I-1) solution had a solid concentration of 50%.

(Note 1) Epoxy group and amino group content: Followed by the following measurement method.
The sample (g) is weighed in an Erlenmeyer flask, and 40 ml of methyl ethyl ketone is added to dissolve it. If difficult to dissolve, heat to 50 ° C to dissolve. Next, 10 ml of CTAB (cetyltrimethylammonium bromide) solution is added with a total pipette to make it uniform. Subsequently, 0.2 ml of screen indicator is accurately added, titrated with an N / 10 perchloric acid-acetic acid solution, and the end point is reached when pink lasts for about 30 seconds with the last drop. Calculated from the following calculated values. The CTAB solution was dissolved by adding 200 ml of acetic acid to 20 g of CTAB, and further adjusted to a uniform solution by adding 200 ml of methyl ethyl ketone. The screen indicator was 1.5 g of thymol blue in a solution of 0.3 g of alphazulin in 100 ml of glacial acetic acid. Was prepared by mixing a solution prepared by dissolving the solution in 500 ml of methanol.
Calculation formula: E = (AB) × 0.1 × F / (S × 0.01 × W)
Where E: epoxy group and amino group content (mmol / g)
A: Amount of N / 10 perchloric acid-acetic acid solution used in this test (ml)
B: Amount of N / 10 perchloric acid-acetic acid solution used in the blank test (ml)
Factor of F: N / 10 perchloric acid-acetic acid solution
S: Sample heating residue (%)
W: Amount of sample (g)

Preparation of urethane prepolymer (II-1) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which "Bisol 3PN" (Note 2) (44.9), "Bisol 6PN "(Note 3) (64.7 g), methyldiethanolamine (20.9 g) was dissolved in N-methylpyrrolidone (45.1 g), and hexamethylene diisocyanate (50.5 g) was added dropwise over 30 minutes. The reaction was carried out at ° C for 1.5 hours. Thereafter, the temperature was raised to 80 ° C., and the reaction was carried out for 2 hours. Isophorone diisocyanate (44.4 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 34 to 41. Thereafter, methyl ethyl ketone (105.1 g) was added to obtain a urethane prepolymer (II-1) solution. The solid content concentration of the obtained urethane prepolymer (II-1) solution was 60.0%, and the amine value of the prepolymer was 43.6 mgKOH / g.

(Note 2) Bisol 3PN: trade name, manufactured by Toho Chemical Co., Ltd., propylene oxide modified bisphenol A (propylene oxide modified amount = 3 mol)
(Note 3) Bisol 6PN: trade name, manufactured by Toho Chemical Co., Ltd., propylene oxide modified bisphenol A (propylene oxide modified amount = 6 mol)
(Note 4) NCO value: The amount of isocyanate group contained in 1 g of urethane prepolymer was converted to the weight of isocyanate (mg), and was tracked by the following measuring method. Sample (g) is correctly weighed into an Erlenmeyer flask, 10 ml of dioxane is added, the dissolved sample is heated to 50 ° C., 10 ml of N / 5 dibutylamine-dioxane solution that has been correctly weighed is added, and the mixture is stirred for 2 minutes. React butylamine. Next, add 2-3 drops of bromophenol blue-ethyl alcohol solution and titrate with N / 10 hydrochloric acid solution, and the end point is when the color changes from blue to yellow-green. In addition, “C” in the following calculation formula is a correction term considering that the tertiary amino group contained in the sample affects the measurement.
Formula N = {0.1 × 42 × (AB) × f} / (0.01 × S × W) + C
Here, N: NCO value (mg of NCO contained in 1 g of sample)
A: Amount of N / 10 hydrochloric acid solution used to neutralize blank N / 5 dibutylamine-dioxane solution (ml)
B: Amount of N / 10 hydrochloric acid solution used for titration of sample (ml)
f: Factor of N / 10 hydrochloric acid solution
S: Sample heating residue (%)
W: Amount of sample (g)
42: Molecular weight of NCO
C: The amount of tertiary amino group contained in the sample (mol) converted to the weight of isocyanate (mg) and calculated by the following formula: C = (D / M × 42 × 1000) / E
Where D: weight of the tertiary amino group-containing monomer compounded during synthesis of the urethane prepolymer (g)
M: Molecular weight of the tertiary amino group-containing monomer compounded during urethane prepolymer synthesis
E: Weight of all blended monomers (g)

Preparation of aqueous polyurethane resin dispersion (A-1) Using a device similar to the above, a 60.0% urethane prepolymer (II-1) solution (375.5 g) was maintained at 50 ° C. in a stirred state. A 50% epoxy prepolymer (I-1) solution (392.2 g) was added thereto and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% aqueous phosphoric acid solution (8.3 g), deionized water (983.3 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (A-1) of polyurethane resin. The solid content concentration of this aqueous dispersion was 30.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 60.4 mgKOH / g.

Synthesis Example 2 (Synthesis of polyurethane resin aqueous dispersion A-2)
Preparation of urethane prepolymer (II-2) Thermometer, stirring device, four-necked flask equipped with a reflux condenser was replaced with nitrogen, Jeffamine M-2070 (200 g), glycerin carbonate (11.8 g) was added, Stir at 100 ° C. for 1 hour. After confirming that the amine value was 1 or less, polyetheramine-modified glycerin carbonate was obtained.
Using the same apparatus as above, among them, “Bisol 3PN” (Note 2) (36.2 g), “Bisol 6PN” (Note 3) (52.2 g), N-methyldiethanolamine (23.1 g), Polyetheramine-modified glycerin carbonate (53.0 g) was dissolved in N-methylpyrrolidone (51.8 g), hexamethylene diisocyanate (50.5 g) was added dropwise over 30 minutes, and the reaction was carried out at 60 ° C. for 1.5 hours. went. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (44.4 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 36 to 43. Thereafter, methyl ethyl ketone (121.0 g) was added to obtain a urethane prepolymer (II-2) solution. The solid content concentration of the obtained urethane prepolymer (II-2) solution was 60.0%, and the amine value of the prepolymer was 41.9 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (A-2) Using a device similar to the above, a 60.0% urethane prepolymer (II-2) solution (432.0 g) was kept at 50 ° C. in a stirred state. A 50% epoxy prepolymer (I-1) solution (392.2 g) was added thereto and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% phosphoric acid aqueous solution (8.9 g), dispersed by adding deionized water (1062.4 g), then heated to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (A-2) of a polyurethane resin. The solid content concentration of this aqueous dispersion was 30.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 55.9 mgKOH / g.

Synthesis Example 3 (Synthesis of aqueous polyurethane resin dispersion A-3)
Preparation of epoxy prepolymer (I-2) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, and an epoxy equivalent of 450 g / eq of bisphenol A type epoxy resin (126 g) was Dissolved in propylene glycol monopropyl ether (27.8 g), 2-aminoethanol (12.8 g) was added thereto, and the mixture was held at 85 ° C. for 3 hours. The epoxy group and amino group content (Note 1) was 1. The reaction was continued until it reached about 5 to 1.55 mmol / g. Thereafter, methyl ethyl ketone (111.1 g) was added to obtain an epoxy prepolymer (I-2) solution. The solid content concentration of the obtained epoxy prepolymer (I-2) solution was 50%.

Preparation of urethane prepolymer (II-3) A four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser was replaced with nitrogen, among which “Bisol 3PN” (Note 2) (44.9 g), “Bisol” 6PN "(Note 3) (64.6 g), methyldiethanolamine (17.9 g), and the polyetheramine-modified glycerin carbonate (53.0 g) prepared in Synthesis Example 2 were dissolved in N-methylpyrrolidone (55.0 g). Then, hexamethylene diisocyanate (50.5 g) was added dropwise over 30 minutes and reacted at 60 ° C. for 1.5 hours. Thereafter, the temperature was raised to 80 ° C. and the reaction was carried out for 2 hours, isophorone diisocyanate (44.4 g) was added, and the mixture was further reacted at 80 ° C. for 3 hours until the NCO value (Note 4) reached about 33-40. Thereafter, methyl ethyl ketone (128.4 g) was added to obtain a urethane prepolymer (II-3) solution. The solid content concentration of the obtained urethane prepolymer (II-3) solution was 60.0%, and the amine value of the prepolymer was 30.6 mgKOH / g.

Preparation of aqueous polyurethane resin dispersion (A-3) Using a device similar to the above, a 60.0% urethane prepolymer (II-3) solution (458.6 g) was maintained at 50 ° C. in a stirred state. A 50% epoxy prepolymer (I-2) solution (198.3 g) was added thereto and stirred for 1 hour. Next, the mixture was cooled to 40 ° C., neutralized with 89% phosphoric acid aqueous solution (7.4 g), deionized water (873.5 g) was added and dispersed, and then the temperature was raised to 70 ° C. and held for 1 hour. Thereafter, methyl ethyl ketone was distilled off under reduced pressure at 60 ° C. to obtain an aqueous dispersion (A-3) of polyurethane resin. The solid content concentration of this aqueous dispersion was 30.0%, the amine value of the polyurethane resin was 30.0 mgKOH / g, and the hydroxyl value was 75.5 mgKOH / g.

Examples 1-9, Comparative Examples 1-4
Production of Metal Surface Treatment Composition A metal surface treatment composition shown in Table 1 below was obtained using each polyurethane resin aqueous dispersion obtained above. In Table 1, the blending amount of the polyurethane resin aqueous dispersion is represented by solid content weight (g), the blending amount of Snowtex N is represented by the solid content weight (g) of silica particles, and the blending of other components. The amount is expressed in weight (g). Each metal surface treatment composition was diluted to 20% solid content with deionized water and subjected to the following test.

Preparation of test plate and evaluation of coating performance Obtained in Table 1 on a 70 mm × 150 mm electrogalvanized steel sheet (trade name: gin coat, plate thickness 0.8 mm, plating adhesion 20 g / m ² ) washed with water after alkali degreasing Each of the obtained metal surface treatment compositions of Examples 1 to 9 and Comparative Examples 1 to 4 was coated using a bar coater so that the dry film weight was 1.2 g / m ^2, and the maximum reached temperature of the steel sheet was Drying was performed at 100 ° C. for 10 seconds. Each of the obtained test plates was subjected to the following various performance tests. The obtained results are shown in Table 1.

（注５）スーパーフレックス ６２０：商品名、第一工業製薬社製、カチオン性ウレタン樹脂水分散体（本発明のポリウレタン樹脂水性分散体（Ａ）とは異なる）、固形分３０％
（注６）スーパーフレックス １５０：商品名、第一工業製薬社製、アニオン性ウレタン樹脂水分散体（本発明のポリウレタン樹脂水性分散体（Ａ）とは異なる）、固形分３０％
（注７）スノーテックスＮ：商品名、日産化学工業社製、コロイダルシリカの水分散液、シリカ粒子の平均粒子径は約２０ｎｍ
（注８）エポクロスＷＳ−７００：商品名、日本触媒社製、オキサゾリン基含有化合物

(Note 5) Superflex 620: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., cationic urethane resin aqueous dispersion (different from aqueous polyurethane resin dispersion (A) of the present invention), solid content 30%
(Note 6) Superflex 150: trade name, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., an anionic urethane resin aqueous dispersion (different from the aqueous polyurethane resin dispersion (A) of the present invention), solid content 30%
(Note 7) Snowtex N: trade name, manufactured by Nissan Chemical Industries, colloidal silica aqueous dispersion, average particle diameter of silica particles is about 20 nm
(Note 8) Epocross WS-700: trade name, manufactured by Nippon Shokubai Co., Ltd., oxazoline group-containing compound

Test method Storage stability test: Each metal surface treatment composition having a solid content of 20% produced in the above Examples and Comparative Examples is allowed to stand in a constant temperature room at 40 ° C., and the state after 15 and 30 days is determined according to the following criteria. evaluated.
○: Neither sedimentation nor gelation ×: Sedimentation or gelation is observed

Fingerprint resistance test: Apply petrolatum to half of the painted surface of the test plate and leave it in a constant temperature room at 20 ° C for 24 hours. The color difference with respect to the surface was measured and evaluated according to the following criteria. The color difference measurement was performed using a Minolta color difference meter “CR-100”.
○: Color difference (ΔE) is less than 2 ×: Color difference (ΔE) is 2 or more

Corrosion resistance test (no degreasing): A salt spray test specified in JISZ2371 was performed for 120 hours on the test plate with the end and back surfaces sealed, and the degree of rust was evaluated according to the following criteria.
◎: Generation of white rust is less than 5% of the coating area ○: Generation of white rust is 5% or more and less than 10% of the coating area △: Generation of white rust is 10% or more of the coating area Less than 30% x: The degree of occurrence of white rust is 30% or more of the coating film area

Corrosion resistance test (after alkaline degreasing): The test plate was degreased at 60 ° C. for 2 minutes using an aqueous solution with a concentration of 2% in which the alkaline degreasing agent CL-N364S (trade name, manufactured by Nihon Parkerizing Co., Ltd.) was dissolved. went. Then, the end surface part and back surface part of the test plate were sealed, the salt spray test prescribed in JISZ2371 was conducted for 120 hours, and the degree of rust was evaluated according to the following criteria.
◎: Generation of white rust is less than 5% of the coating area ○: Generation of white rust is 5% or more and less than 10% of the coating area △: Generation of white rust is 10% or more of the coating area Less than 30% x: The degree of occurrence of white rust is 30% or more of the coating film area

Solvent resistance test: Using four layers of gauze impregnated with ethanol, the coating film surface of the test plate was rubbed 5 times, and the appearance was visually evaluated according to the following criteria.
○: Rub marks are not noticeable Δ: Rub marks are conspicuous ×: Film is dissolved

Topcoat film adhesion test: Magcron # 1000 (trade name, manufactured by Kansai Paint Co., Ltd., color white), which is a thermosetting acrylic paint, is applied on the test plate so that the film thickness is 25 μm. 150 A coated plate was prepared by baking at 20 ° C. for 20 minutes. Then, a grid pattern (10 × 10 grid pattern at 1 mm intervals) was cut into the coated plate, and adhesion and peeling with an adhesive tape were performed. The number of coating films remaining in the grid was evaluated according to the following criteria.
◎: 100 pieces ○: 80 to 99 pieces Δ: 50 to 79 pieces ×: 49 pieces or less

Claims (6)

(A) an epoxy prepolymer (I) having a secondary amino group obtained by a reaction between a polyepoxy compound (a) and an amine compound (b) containing a polyoxyalkyleneamine as at least a part of the component , and its component A compound (c) containing two or more hydroxyl groups in one molecule containing a polyol having a polyoxyalkylene chain serving as a side chain as at least a part of the polyisocyanate compound (d) and 2 active hydrogen groups in one molecule A polyurethane resin obtained by a reaction with a urethane prepolymer (II) having an isocyanate group, which is obtained by a reaction with a compound (e) containing at least two and containing a tertiary amino group , the epoxy prepolymer ( I) and the urethane prepolymer (II) both have a polyoxyalkylene chain in the side chain. And (B) at least one selected from phosphoric acid compounds, vanadium compounds, zirconium compounds, titanium compounds, cobalt compounds, nickel compounds, silane coupling agents, and silica particles. A metal surface treatment composition. Obtained by reacting the epoxy prepolymer (I) such that the equivalent ratio of the epoxy group in the polyepoxy compound (a) to the amino group in the amine compound (b) is 1: 0.5 to 1: 2. The metal surface treatment composition according to claim 1. The polyol having a polyoxyalkylene chain as a side chain is at least one selected from a reaction product of an acrylate having a polyoxyalkylene chain and a dialkanolamine, and a reaction product of glycerin carbonate and a polyoxyalkyleneamine. The metal surface treatment composition according to claim 1 . The metal surface treatment composition according to claim 1, wherein the urethane prepolymer (II) is obtained by reacting so that an equivalent ratio of isocyanate groups to hydroxyl groups in all components is 1: 0.5 to 1: 0.9. object. A polyurethane resin is obtained by reacting such that the equivalent ratio of the amino group in the epoxy prepolymer (I) and the isocyanate group in the urethane prepolymer (II) is 0.01: 1 to 0.9: 1. The metal surface treatment composition according to claim 1. The metal plate formed by apply | coating 0.1-3.0 g / m < ² > by dry film weight with the metal surface treatment composition of any one of Claims 1-5 on a steel plate.