JP2009137283A - Surface treated metallic plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treated steel plate having excellent corrosion resistance, deep drawing workability and coating property. <P>SOLUTION: The surface treated metallic plate has a resin coating film on the surface of the metallic plate, wherein the resin coating film is formed from a resin coating film forming composition containing 30-50 pts.mass acrylic urethane based resin, 50-70 pts.mass silica particles having 4-20 nm average particle diameter to become 100 pts.mass in total of both acrylic urethane based resin and the silica particles, and further containing 5-25 pts.mass silane coupling agent based on 100 pts.mass in total of the acrylic urethane based resin and the silica particles. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a surface-treated metal plate excellent in deep drawability, and more specifically, deep draw products used for automobiles, home appliances, building materials such as audio chassis, computer cases, motor cases, pulleys, and the like. It is related with the surface treatment metal plate suitable for.

  Materials used for household electrical appliance parts include galvanized steel sheets such as electrogalvanized steel sheets and hot dip galvanized steel sheets, and chromate treatment and phosphorous on the galvanized steel sheets for the purpose of further improving corrosion resistance and paintability. An inorganic film-treated steel sheet that has been subjected to chemical conversion treatment such as acid salt treatment is often used. In addition, for the purpose of further improving corrosion resistance and improving paintability and workability, resin-coated steel sheets in which an organic resin film is formed on a surface-treated steel sheet that has been subjected to chromate treatment have been proposed.

  However, when deep drawing is performed, such as motor cases in home appliances, severe sliding friction occurs between the resin-coated steel sheet and the mold during processing, so the resin film on the sliding surface peels off. As a result, a blackening phenomenon that turns black occurs, and the appearance of the product is remarkably impaired, and the generated black matter adheres to peripheral equipment and causes other problems.

  Various improved resin films have been proposed for the purpose of solving these problems. For example, a lubricating steel sheet having an inorganic polymer compound and a solid lubricant formed thereon, an inorganic polymer compound, and a solid lubricant can be used. In addition, a lubricated steel sheet in which a resin film having a water-soluble resin is formed has been proposed. However, the coated steel sheet based on inorganic polymers is resistant to scratching and the effect of improving the blackening of the film at the time of deep drawing, but the repelling that occurs when the solution is applied to the steel sheet. Due to coating defects and high water permeability of the film, black spot rust and white rust are easily generated, and the coating film has poor adhesion when coated.

  In recent years, the use of steel plates that do not use hexavalent chromium has been expanded in place of the chromate treatment that has been conventionally used for the purpose of improving the corrosion resistance of galvanized steel plates due to increasing awareness of environmental issues. For this reason, development of a film having better corrosion resistance is expected.

A surface-treated metal plate having a carboxyl group-containing polyurethane resin or a mixture of a carboxyl group-containing polyurethane resin and an ethylene-unsaturated carboxylic acid copolymer has been proposed as a resin film for further improving the corrosion resistance (patent) References 1, 2).
JP 2005-200777 A JP 2006-43913 A

  However, in recent years, the performance and miniaturization of electrical products have further progressed, and the processing conditions for steel sheets have become more severe as the required level for the dimensional accuracy of processed products has become stricter. In particular, when deep drawing is performed, in order to improve dimensional accuracy, a forming device having a clearance narrower than the thickness of the steel plate to be processed may be used. There has been a problem that intense sliding friction occurs between the mold and the product appearance of the sliding surface is deteriorated. Since such a problem also occurs in the above-described conventional coated steel sheet, there is an increasing demand for improvement in the appearance of the product after processing.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a surface-treated metal plate having further improved corrosion resistance, paintability and deep drawing workability.

  The surface-treated metal plate of the present invention that was able to solve the above-mentioned problem is a surface-treated metal plate having a resin film on the surface of the metal plate, and the resin film comprises 30 to 50 parts by mass of an acrylic urethane resin, 50 to 70 parts by mass of silica particles having an average particle diameter of 4 to 20 nm are contained so that the total of both becomes 100 parts by mass, and further, with respect to a total of 100 parts by mass of the acrylurethane resin and silica particles. And it has the characteristics in that it is formed from the resin composition for film formation which contains a silane coupling agent in the ratio of 5-25 mass parts.

  The acrylic urethane-based resin contains polyisocyanate, polyol and dihydroxyalkanoic acid as raw materials, and a polyurethane obtained from a urethane prepolymer synthesized from 3 to 80 parts by mass of these, and 10 to 97 parts by mass of ( The (meth) acrylic polymer obtained from a (meth) acrylic monomer is preferably included, and the acrylic urethane-based resin contains a carbonyl group and / or a polyurethane and / or (meth) acrylic polymer in the structure thereof. Or it is preferable to have a hydrazine group. In particular, it is preferable that the acrylic urethane resin has a softening point of 120 ° C. or higher and a pseudo rocker hardness of 25 or higher. More preferably, the resin film has an azomethine cross-linked structure.

  The silane coupling agent preferably has a structure represented by the following chemical formula (1).

(In the above chemical formula (1), R ¹ is a glycidoxy group or epoxycyclohexyl group, R ² and R ³ are lower alkoxy groups, R ⁴ is a lower alkoxy group or lower alkyl group, and X is a lower alkylene group.)

Moreover, it is desirable that the amount of the resin film adhered to the metal plate is 0.05 to 1 g / m ² .

  The surface-treated metal plate of the present invention is excellent in corrosion resistance, deep drawing workability and paintability.

  The surface-treated metal plate of the present invention is a surface-treated metal plate having a resin film on the surface of the metal plate, wherein the resin film is silica having an acrylic urethane type resin of 30 to 50 parts by mass and an average particle diameter of 4 to 20 nm. The composition for resin film formation which contains 50-70 mass parts of particle | grains, and also contains a silane coupling agent in the ratio of 5-25 mass parts with respect to a total of 100 mass parts of the said acrylic urethane type resin and a silica particle. It is formed from an object. Hereinafter, the present invention will be described in detail.

(1) Resin composition for film formation (1-1) Acrylic urethane type resin The acrylic urethane type resin used by this invention contains a (meth) acrylic-type polymer and a polyurethane. As described above, when the (meth) acrylic polymer and polyurethane are used in combination, if only the (meth) acrylic polymer is used as the resin component, a resin film having high hardness is obtained, so that the workability (blackening resistance) is Although it is ensured, since the flexibility is low, the resin film is cracked and the corrosion resistance is likely to be lowered. Therefore, a polyurethane that can give flexibility to the obtained resin film, has excellent chemical resistance and abrasion resistance, and can give toughness to the obtained resin film is used in combination with a (meth) acrylic polymer. In particular, the workability and flexibility of the resin film (surface-treated metal plate) were made compatible.

  The object of the present invention is to prevent appearance defects such as blackening even when severe processing conditions using a mold having a clearance narrower than the thickness of the steel plate to be processed are employed. The provision of surface-treated steel sheets. When the severe processing conditions as described above are employed, a large force is momentarily applied to the steel sheet. At this time, the resin film provided on the surface of the metal plate needs to have a hardness that can withstand an impact caused by contact with the forming apparatus and a flexibility that can follow the deformation of the steel plate. Therefore, in the present invention, in order to obtain a surface-treated steel sheet having both of these properties, the acrylic urethane-based resin having the above configuration is adopted.

  As the (meth) acrylic monomer component constituting the (meth) acrylic polymer, monomers having a carboxyl group such as (meth) acrylic acid, itaconic acid, crotonic acid, ethyl 2-hydroxy (meth) acrylate, 2 -Monomers having a hydroxyl group, such as propyl hydroxy (meth) acrylate and butyl 4-hydroxy (meth) acrylate, and (meth) acrylate esters.

  Examples of acrylic esters include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, isononyl acrylate, isobornyl acrylate, N, N-dimethylaminoethyl acrylate, isobutyl acrylate, Examples include 2-methoxyethyl acrylate, 3-methoxybutyl acrylate, lauryl acrylate, n-stearyl acrylate, tetrahydrofurfuryl acrylate, trimethylolpropane acrylate, and 1,9-nonanediol acrylate. Methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, alkyl methacrylate, tridecyl methacrylate, Stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, isobornyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate, 2-methoxyethyl methacrylate, 2-ethoxyethyl methacrylate, ethylene glycol dimethacrylate, Triethylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, polypropylene dimethacrylate Recall, trimethylolpropane trimethacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, trifluoroethyl methacrylate, and the like methacrylic acid heptadecafluorodecyl. These (meth) acrylic monomer components can be used by selecting one type or two or more types as necessary.

  Among the above (meth) acrylic monomer components, butyl acrylate and n-butyl methacrylate are particularly preferable.

  The polyurethane according to the present invention is preferably obtained by polymerizing a polyisocyanate, a polyol and a hydroxyalkanoic acid, and more preferably, a urethane prepolymer is synthesized from the polyisocyanate, the polyol and the hydroxyalkanoic acid. It was obtained by chain extension reaction.

  The polyisocyanate component constituting the urethane prepolymer is preferably one having two or more isocyanate groups in one molecule, specifically, 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4-toluene diisocyanate, 1,4-naphthalene diisocyanate, 1,5-naphthalene diisocyanate, 1,2-phenylene diisocyanate, Yellowed polyisocyanates such as 1,3-phenylene diisocyanate and 1,4-phenylene diisocyanate; o-xylylene diisocyanate, p-xylylene diisocyanate, m-xylylene diiso Non-yellowing polyisocyanate such as anate; 4,4′-dicyclomethane diisocyanate, 2,4′-dicyclomethane diisocyanate, 2,2′-dicyclomethane diisocyanate, hexamethylene diisocyanate, tetramethylxylylene diisocyanate, Non-yellowing polyisocyanates such as isophorone diisocyanate and lysine diisocyanate; and polymers such as crude toluene diisocyanate and polyphenylene polymethylene isocyanate. These polyisocyanates may be used alone or in admixture of two or more. Among the polyisocyanates, it is most preferable to use a non-yellowing type isocyanate from the viewpoint of maintaining a good appearance of the metal plate.

  As a polyol component which comprises the said urethane prepolymer, what has a 2 or more hydroxyl group in 1 molecule is preferable, and any of a low molecular weight type and a high molecular weight type can be used. Low molecular weight types include ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, propylene glycol, butylene glycol, hexamethylene glycol, neopentyl glycol, 1,4-cyclohexanedimethanol, sorbitol, pentaerythritol, glycerin, trimethylol Examples thereof include propane and trimethylolethane. Among the low molecular weight type polyols, trimethylolpropane and 1,4-cyclohexanedimethanol are preferable. Moreover, as a high molecular weight type, polyether polyol, polyester polyol, epoxy polyol, silicon polyol and the like can be mentioned.

  Examples of the polyether polyol include products obtained by polymerization of cyclic oxides such as ethylene oxide, propylene oxide, and tetrahydrofuran, or one or more cyclic oxides, water, ethylene glycol, propylene glycol. , Diethylene glycol, cyclohexanedimethanol, glycerin, trimethylolpropane, pentaerythritol, or a product obtained by adding to bisphenol A.

  Examples of the polyester polyol include those obtained by polycondensation of a diol and a dibasic acid. Examples of the diol component include ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, Examples of the dibasic acid include 1,5-methylpentanediol, 1,4-cyclohexanedimethanol, and adipic acid, isophthalic acid, terephthalic acid, azelaic acid, sebacic acid, and other dimer acids. The “dimer acid” is usually produced by dimerizing an unsaturated long-chain aliphatic monocarboxylic acid having 13 to 22 carbon atoms or an ester thereof, specifically, having 18 and 18 carbon atoms. Examples include dimer acids having 36 or 44 carbon atoms derived from 22 unsaturated carboxylic acids, and dimer acids derived from unsaturated fatty acids having 18 carbon atoms including acids such as linoleic acid and linolenic acid. Among the polyester polyols, dimer acid-containing polyester polyols are preferable.

  Examples of the dihydroxyalkanoic acid constituting the urethane prepolymer include 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, dimethylolbutanoic acid, and the like. From the viewpoint of properties and the like, dimethylolpropionic acid and dimethylolbutanoic acid are preferably used.

  The resin film of the surface-treated metal plate of the present invention preferably has an azomethine cross-linked structure. The azomethine crosslinked structure is a structure represented by the following formula (2), and is formed by a reaction between an organic hydrazine compound and a ketone or aldehyde carbonyl compound.

  By forming the azomethine cross-linked structure in the resin film, the fastness to reciprocating friction by the ethanol-impregnated cloth is improved, and the Kenich hardness and 100% modulus (tensile stress at 100% elongation) of the resin film are increased. Therefore, various physical properties of the surface-treated metal plate can be improved. In addition, since the reaction between the organic hydrazine compound and the carbonyl compound proceeds by removal (volatilization) of water in the coating film and the alkali component used for neutralization of the resin, such a condition is established. For example, it proceeds regardless of temperature. Therefore, it is not necessary to perform a special operation for the crosslinking reaction. Further, since it is self-crosslinking, it is not necessary to add a crosslinking agent such as formaldehyde for the crosslinking reaction.

  As an aspect of the acrylic urethane-type resin which can form the said azomethine bridge | crosslinking, the following 1-3 forms are mentioned.

1: an aspect in which the acrylic urethane-based resin includes at least one polyurethane having a hydrazine group and at least one (meth) acrylic polymer having a carbonyl group,
2: The aspect in which the acrylic urethane-based resin includes a compound in which at least one polyurethane and at least one (meth) acrylic polymer each have a carbonyl group and have at least two hydrazine groups;
3: The aspect in which the acrylic urethane resin includes a compound in which at least one polyurethane and at least one (meth) acrylic polymer each have a hydrazine group and at least two carbonyl groups.

  Introducing a hydrazine group into polyurethane can be achieved by using a hydrazine compound having reactivity with an isocyanate group such as a hydroxyl group or a chain extender having a hydrazine group at the time of the synthesis of the urethane prepolymer or the chain extension reaction of the urethane prepolymer. Good. At this time, in order to prevent the hydrazine group from reacting, it is necessary to block the hydrazine group with a monoaldehyde or a monoketone. Examples of such hydrazine compounds include γ-hydroxybutyl hydrazide capped with a aldehyde or monoketone, carbazine aldehyde blocked with a ketone / aldehyde having a boiling point of 30 to 200 ° C., and reacted with ethanolamine. And methacrylate. The said hydrazine compound can be manufactured by making the reaction product of a diamine and 0.2-2 mol (meth) acrylic acid derivative (preferably ethyl acrylate) react with hydrazine. The monoaldehyde and monoketone used for blocking the hydrazine group were used for water dispersion of the resin composition when drying a resin coating film formed from a film forming resin composition containing a urethane acrylic resin. The alkali component is removed, and the inside of the coating system is acidified to be detached from the hydrazine group. As a result, a hydrazine group is generated and an azomethine crosslinking reaction occurs.

  Examples of the diamine include aliphatic diamines having 2 to 15 carbon atoms, alicyclic and aromatic diamines having 6 to 15 carbon atoms, and specific examples include ethylene diamine, 1,4-butane diamine, 1,6- Hexanediamine, 2-methyl-1,5-pentanediamine, 2,2,2-trimethyl-1,6-hexanediamine, 2,2,4- and 2,4,4-trimethyl-1,6-hexanediamine And bis (4-aminocyclohexyl) methane and di (aminomethyl) benzene.

  In addition, when using the polyurethane which has a hydrazine group, it is preferable that the quantity of the hydrazine group in 100 g of polyurethanes is 2-500 milliequivalents. More preferably, it is 20-200 milliequivalent, More preferably, it is 50-115 milliequivalent. Therefore, the amount of the hydrazine compound used is such that the functional group having reactivity with the isocyanate group in the hydrazine compound is 100 to 1000 milliequivalents with respect to 1 equivalent of the isocyanate group of the polyisocyanate constituting the polyurethane. It is preferable to make it, more preferably 300 to 800 milliequivalent, still more preferably 450 to 600 milliequivalent.

  The introduction of the carbonyl group into the polyurethane may be performed by using a carbonyl compound having one, preferably two or more functional groups having reactivity with an isocyanate group during the synthesis of the urethane prepolymer or the chain extension reaction of the urethane prepolymer. That's fine. Examples of such carbonyl compounds include dihydroxy ketones such as dihydroxyacetone, and products obtained by Michael addition reaction of diacetone acrylamide with diamine or alkanolamine. Moreover, as a carbonyl compound which can be used at the time of chain extension reaction, the Michael addition product of 2 mol diacetone acrylamide and 1 mol diamine is mentioned.

  In addition, when using the polyurethane which has a carbonyl group, it is preferable that the quantity of the carbonyl group in 100 g of polyurethanes is 2-230 milliequivalent. More preferably, it is 5-180 milliequivalent, More preferably, it is 10-55 milliequivalent. Therefore, the amount of the carbonyl compound used is such that the functional group having reactivity with the isocyanate group in the carbonyl compound is 8 to 880 milliequivalents with respect to 1 equivalent of the isocyanate group of the polyisocyanate constituting the polyurethane. More preferably, it is 19-690 milliequivalent, and still more preferably 38-211 milliequivalent.

  On the other hand, a (meth) acrylic polymer having a hydrazine group is obtained by polymerizing a monomer component having a functional group that reacts with hydrazine or hydrazine monohydrate to generate a hydrazine group. Specific monomer components include crotonic acid, α-chloroacrylic acid, (meth) acrylic acid, acid chloride or esters thereof, and (meth) acrylic esters of low molecular weight alcohols are particularly preferably used. Low molecular weight alcohol (meth) acrylic acid esters include: (meth) acrylic acid methyl ester, (meth) acrylic acid ethyl ester, (meth) acrylic acid propyl ester, (meth) acrylic acid isopropyl ester, (meth) acrylic acid Examples thereof include n-butyl ester. Further, as a copolymerization component, a vinyl halide such as vinyl chloride, vinyl fluoride or vinylidene chloride, a vinyl-aryl compound such as styrene or substituted styrene, a compound having a vinyl group such as butadiene or 2-chlorobutadiene may be used. Good. These monomer components can be used alone or in combination of two or more.

  A (meth) acrylic polymer having a hydrazine group is obtained by reacting a homo- or copolymer obtained by polymerizing the monomer component with hydrazine or hydrazine monohydrate. In addition, it is preferable that the functional group which can be converted into a hydrazine group exists in 5-300 milliequivalents in 100 g of (meth) acrylic-type polymers. More preferably, it is 10-200 milliequivalent, More preferably, it is 20-150 milliequivalent. Moreover, it is preferable that the usage-amount of the said hydrazine or hydrazine monohydrate shall be 5-300 milliequivalent with respect to 100 g of (meth) acrylic-type polymers, More preferably, it is 10-200 milliequivalent.

  In addition, when synthesizing a (meth) acrylic polymer to produce polyurethane (performing a chain extension reaction of a urethane prepolymer), the hydrazine group introduced into the (meth) acrylic polymer is replaced with a monoaldehyde or monoketone. It is preferable to block it.

  The introduction of the carbonyl group into the (meth) acrylic polymer may be performed using a carbonyl group-containing monomer as the (meth) acrylic monomer component. Examples of such carbonyl group-containing monomers include acrolein, methacrolein, diacetone acrylamide, acrylamide pivalaldehyde, methacrylamide pivalaldehyde, diacetone acrylate, and the like. In addition, when using the (meth) acrylic-type polymer which has a carbonyl group, it is preferable that the quantity of the carbonyl group in 100 g of (meth) acrylic-type polymers is 2-230 milliequivalent. More preferably, it is 5-180 milliequivalent, More preferably, it is 10-55 milliequivalent.

  Examples of the compound having two hydrazine groups used in the second embodiment include dicarboxylic acid dihydrazide, and specific examples include oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide and the like. Is mentioned. Examples of the compound having two carbonyl groups used in the third embodiment include di- or polyketones or poly-aldehydes such as glyoxal, 2,5-hexanedione, glutardialdehyde, and succinic dialdehyde.

  When a polyurethane having a hydrazine group and a poly (meth) acrylic polymer having a carbonyl group are used (the above-described aspect 1), the blending amount thereof is carbonyl with respect to 1 equivalent of the hydrazine group present in the polyurethane. Preferably 0.02 to 1.6 equivalents of groups are present. More preferably, it is 0.05-0.9 equivalent.

  When the compound having the two hydrazine groups is used (that is, in the second aspect), the amount of the compound used is the carbonyl group derived from the polyurethane and / or the (meth) acrylic polymer in the acrylic urethane resin. It is preferable to be 0.02 to 1.6 equivalents relative to 1 equivalent, and more preferably 0.05 to 0.9 equivalents.

  On the other hand, when the compound having two carbonyl groups is used (the third aspect), the amount used is a hydrazine group derived from a polyurethane and / or (meth) acrylic polymer present in the acrylic urethane resin. It is preferable to be 0.02 to 1.6 equivalents relative to 1 equivalent, and more preferably 0.05 to 0.9 equivalents.

  The acrylic urethane resin may be a mixture of a separately synthesized (meth) acrylic polymer component and a polyurethane component. In the present invention, after synthesizing a polyurethane or urethane prepolymer, the polyurethane ( (Or urethane prepolymer) in the same system as the one synthesized, and (meth) acrylic monomers are preferably polymerized in the presence thereof. This is because, by synthesizing the polyurethane and the (meth) acrylic polymer in the same system, the mixed state of the polyurethane and the (meth) acrylic polymer in the acrylic urethane resin can be maintained more uniformly.

  Therefore, as a method for producing the acrylic urethane resin according to the present invention, a conventionally known method is used without particular limitation as long as the acrylic component is polymerized in the same system after the urethane component is synthesized. . As will be described later, since the acrylic urethane resin according to the present invention is used as an aqueous dispersion, it is preferably used as an aqueous dispersion in the production stage of the acrylic urethane resin. For example, following the production of the urethane prepolymer, a polymerization reaction of the (meth) acrylic monomer component is performed, and then the obtained acrylic urethane resin is dispersed in water; the urethane prepolymer is produced and dispersed in water. Thereafter, a method of polymerizing a (meth) acrylic monomer component may be mentioned. Moreover, a (meth) acrylic-type monomer can also be used as a solvent at the time of the synthesis | combination of a urethane prepolymer by adding a (meth) acrylic-type monomer in the synthesis | combination system of a urethane prepolymer with a polymerization inhibitor. In this case, after synthesizing the urethane prepolymer, a (meth) acrylic monomer may be polymerized by adding a radical polymerization initiator.

  The mixing ratio of the polyisocyanate and the polyol when synthesizing the urethane prepolymer is preferably 1.0 to 2.0 in terms of NCO / OH ratio, more preferably 1.2 to 1.9, Preferably it is 1.3-1.7.

  The amount of hydroxyalkanoic acid used relative to polyisocyanate and polyol is preferably such that the acid value of the urethane prepolymer is 20 to 80 mgKOH / g.

  Although the temperature at the time of a urethane prepolymer synthesis | combination is not specifically limited, It is preferable to set it as the temperature of 60-95 degreeC. Moreover, in the synthesis | combination of a urethane prepolymer, you may use a polymerization catalyst as needed. Examples of the polymerization catalyst include organic compounds such as tin (II) salts of carboxylic acids, strong bases such as tertiary amines, alkali metal hydroxides, alcoholates and phenolates. Specific examples include di-n-octyl mercaptide, dibutyltin maleate, dibutyltin diacetate, and dibutyltin dilaurate.

  The urethane prepolymer preferably has a weight average molecular weight (Mw) of 400 to 10,000. More preferably, it is 3000-9000, More preferably, it is 4000-8000. In addition, the said weight average molecular weight is a value measured by gel permeation chromatography (GPC) (polystyrene conversion value).

  The polyurethane component according to the present invention is preferably obtained by extending a urethane prepolymer with a chain extender. The chain extension reaction can be performed before water dispersion, after water dispersion, or simultaneously with water dispersion.

  Chain extenders include ethylenediamine, diethylenetriamine, triethylenetetramine, propylenediamine, butylenediamine, hexamethylenediamine, cyclohexylenediamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylylenediamine, tris (2 -Aminoethyl) amine, 3,3′-dinitrobenzine, 4,4′-diaminophenylmethane, menthanediamine, m-xylenediamine, isophoronediamine, isophoronediamine, hydrazine derivatives, or water. The hydrazine derivative is most preferable. Examples of the hydrazine derivative include hydrazine; hydrazine monohydrate; mono-substituted hydrazine such as methyl hydrazine and ethyl hydrazine; hydroxyalkyl-substituted hydrazine such as 2-hydroxyethyl hydrazine and 2-hydroxypropyl hydrazine; methylene dihydrazine, ethylenedi Alkylene hydrazines such as hydrazine and propylene dihydrazine; oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, aliphatic dicarboxylic acid hydrazide, unsaturated aliphatic dicarboxylic acid hydrazide, aromatic Dihydrazides such as dicarboxylic acid hydrazide, maleic acid dihydrazide, phthalic acid dihydrazide, isophthalic acid dihydrazide, carbodihydrazide It is. Of these, hydrazine monohydrate is preferably used.

  The chain extender is preferably used so that the functional group in the chain extender is 0.3 to 1.7 equivalents relative to 1 equivalent of the NCO group in the urethane prepolymer, more preferably 0.8. It is 5-1.5 equivalent, More preferably, it is 0.8-1.2 equivalent.

  The urethane prepolymer or polyurethane can be emulsified and dispersed in water by neutralization with a base. At this time, if a (meth) acrylic polymer containing a carboxyl group or a carboxyl group alkyl ester (described later in detail) is present in the system, the (meth) acrylic polymer is the same as the urethane prepolymer or polyurethane. The originating carboxyl group is also neutralized. Examples of neutralizing agents that can be used at this time include hydroxides of alkali metals and alkaline earth metals such as sodium hydroxide, potassium hydroxide, barium hydroxide, and lithium hydroxide; ammonia; triethylamine, N, N-dimethylbutylamine. , N, N-dimethylallylamine, N-methylpyrrolidine, tetramethyldiaminomethane, trimethylamine and other tertiary amines; N-methylethylamine, diisopropylamine, diethylamine and other secondary amines; propylamine, t-butylamine, sec-butylamine , Isobutylamine, 1,2-dibutylpropylamine, primary amines such as 3-pentylamine; morpholine compounds such as morpholine, N-methylmorpholine, N-ethylmorpholine; piperazine, hydroxyethylpiperazine, 2-methylpi Piperazine compounds such as azine and aminoethylpiperazine; N, N-diethylethanolamine, N, N-dibutylethanolamine, N- (β-aminoethyl) ethanolamine, N-methylethanolamine, N-methyldiethanolamine, N-ethylethanolamine, Nn-butylethanolamine, Nn-butyldiethanolamine, Nt-butylethanolamine, Nt-butyldiethanolamine, N- (β-aminoethyl) isopropanolamine, N, N -Amino alcohols such as diethyl isopropanolamine, 2-amino-2-methyl-1-propanol; ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, aminoethyl Diamines such as ethanolamine, 1,6-hexamethylenediamine, metaxylylenediamine, 1,2-diaminopropane, 1,4-diaminobutane; coconutamine, octylamine, laurylamine, stearylamine, oleylamine, etc. Examples thereof include aliphatic amines and EO adducts thereof. Among these, ammonia and triethylamine which are volatilized at the time of film formation and do not cause a remaining neutralizing agent are desirable, and triethylamine is more desirable.

  The above (meth) acrylic monomer and polymerization initiator are added to the system after the synthesis of the urethane prepolymer or after the chain extension reaction of the urethane prepolymer, and the (meth) acrylic monomer is added to the reaction solvent. When used as a polymerization initiator, a (meth) acrylic monomer is polymerized by adding a polymerization initiator into the system after the synthesis of the urethane prepolymer or after the chain extension reaction of the urethane prepolymer.

  The amount of the (meth) acrylic monomer used is preferably 10 to 97 parts by mass with respect to a total of 3 to 80 parts by mass of the polyisocyanate, polyol and hydroxyalkanoic acid that are constituents of the urethane prepolymer. In this case, the use ratio of the urethane prepolymer and the (meth) acrylic monomer depends on the glass transition temperature of the (meth) acrylic polymer to be produced, but the total of the urethane prepolymer and the (meth) acrylic monomer. Is 100 parts by mass, preferably 3 to 50 parts by mass of the urethane prepolymer component, and preferably 50 to 97 parts by mass of the (meth) acrylic monomer, and 3 to 40 parts by mass of the urethane prepolymer component. The (meth) acrylic monomer is more preferably 60 to 97 parts by mass. The glass transition temperature of the (meth) acrylic polymer derived from the Fox formula is preferably -30 to 90 ° C, more preferably -20 to 80 ° C. The acid value of the (meth) acrylic polymer according to the present invention is preferably 0 to 400 mgKOH / g.

  As polymerization initiators during polymerization of (meth) acrylic monomers, azo compounds such as azobisisobutyronitrile and its hydrochloride, 4,4′-azobis (4-cyanovaleric acid); benzoyl peroxide, dicumyl Peroxidation of organic peroxides such as peroxides, lauroyl peroxide, cumene hydroperoxide, and inorganic peroxides such as potassium persulfate, sodium persulfate, ammonium persulfate, perborate, persuccinate Things.

  The amount of the polymerization initiator used is preferably 0.05 to 3% by mass with respect to the total mass of the (meth) acrylic monomer. Although the temperature at the time of (meth) acrylic-type monomer polymerization is not specifically limited, Preferably it is 30-30 degreeC, More preferably, it is preferable to perform a polymerization reaction at 50-70 degreeC.

  The (meth) acrylic monomer may be emulsified prior to the polymerization reaction. For example, it can be carried out simultaneously with the emulsification of the urethane prepolymer or at the time of chain extension of the urethane prepolymer. It is preferable to carry out simultaneously with emulsification. If desired, an anionic surfactant may be used.

  In synthesizing the acrylic urethane resin of the present invention (synthesis of the urethane prepolymer, chain extension reaction of the urethane prepolymer and polymerization reaction of the (meth) acrylic polymer), a known organic solvent can be used. Organic solvents include aromatic solvents such as toluene and xylene; ester solvents such as methyl acetate and ethyl acetate; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ethylene glycol monomethyl ether acetate, propylene glycol mono Examples include glycol ether ester solvents such as ethyl ether acetate; alcohol solvents such as methanol, ethanol, and isopropanol; solvents such as dimethylformamide, dimethylacetamide, and N-methylpyrrolidone. These organic solvents can be used alone or in combination of two or more. Moreover, you may use a (meth) acryl monomer component as a solvent in the case of superposition | polymerization of a urethane component. In this case, any known polymerization inhibitor can be used as long as it is a conventionally known polymerization inhibitor, and methoxyphenol is preferable.

  In the present invention, the acrylic urethane-based resin is desirably a self-dispersing type that is easily dispersed in water or an aqueous solvent containing water as a main component (50% by mass or more). However, when the acrylic urethane-based resin is difficult to disperse in water or an aqueous solvent, if this is mechanically dispersed, the particle size of the emulsion may increase and storage stability may be inferior. Therefore, in such a case, a surfactant may be used as necessary.

  As the surfactant, conventionally known surfactants such as nonionic, anionic, and cationic surfactants can be used. However, depending on the purpose, the type and amount used may be used so that the expression of the effect of the invention is not inhibited. It is desirable to select. Nonionic surfactants include polyoxyethylene octyl ether, polyoxyethylene decyl ether, polyoxyethylene dodecyl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene Oxyethylene isostearyl ether, polyoxyethylene behenyl ether, polyoxyethylene-2-ethyl-hexyl ether, polyoxyethylene alkyl ether, polyoxyethylene alkyl ether (synthetic system), narrow type polyoxyethylene alkyl ether, polyoxy Ethylene octyldodecyl (Gerbe type) ether, polyoxyethylene styrenated phenyl ether, polyoxyethylene β-naphthy Ethers, polyoxyethylene hydrogenated castor oil ether, polyethylene glycol monoalkyl fatty acid esters, polyethylene glycol dialkyl fatty acid esters, and polyoxyethylene sorbitan monolaurate and the like.

  In addition, since it may be difficult to obtain a stable aqueous dispersion only with a nonionic surfactant, it is desirable to use an anionic surfactant, a reactive surfactant or the like together. Examples of the anionic surfactant include semi-cured tallow fatty acid soap Na salt, stearic acid soap Na salt, oleic acid soap K salt, gum rosin disproportionated rosin sodium salt, alkenyl succinic acid dipotassium salt, dodecyl sulfate Na salt, polyoxy Examples thereof include ethylene alkyl (C12, C13) ether sulfate Na salt, polyoxyethylene dodecyl sulfate ammonium salt, dodecylbenzene sulfonate Na salt, higher alkyl monoamine salt and dialkylethylmethylethyl ammonium sulfate salt as cationic activators.

  Examples of the reactive surfactant include polyoxyethylene alkylphenyl ether and its sulfate ester salt, sulfosuccinic acid type, alkenyl polyoxyalkylene phosphate ester, polyoxyethylene alkyl ammonium phosphate glycidyl ether adduct, and the like. . Further, a protective colloid such as polyvinyl alcohol may be used in place of the surfactant.

  As a specific method for forming an aqueous dispersion, for example, a (meth) acrylic monomer-containing prepolymer is neutralized with an amine, and then a surfactant, a polymerization catalyst and water are added thereto to cause a polymerization reaction. A method of dispersing a polymer in an aqueous dispersion by adding a neutralized (meth) acrylic monomer-containing prepolymer with an amine and a polymerization catalyst to an aqueous solution comprising a surfactant and water, and carrying out a polymerization reaction. There is a method in which the polymer is dispersed in water. In any case, the amount of the surfactant used is preferably 0 to 30% by mass relative to the total mass of the (meth) acrylic monomer. In the above method, the (meth) acrylic monomer-containing prepolymer may be emulsified after the neutralizing agent (amine) is mixed with water.

(1-2) Blending amount of acrylic urethane-based resin The resin composition for forming a film used in the present invention is 30 to 50 parts by mass of the acrylic urethane-based resin described above and silica particles 50 to 4 having an average particle diameter of 4 to 20 nm. 70 mass parts is contained so that it may become a total of 100 mass parts, and the silane coupling agent is further contained in the ratio of 5-25 mass parts with respect to the said 100 mass parts in total. In addition, when using the aqueous dispersion of acrylic urethane type resin, it is preferable that the non-volatile resin component of an acrylic urethane type resin aqueous dispersion shall be 30-50 mass parts.

  When the said acrylic urethane type resin component decreases too much, there exists a tendency for corrosion resistance and paintability to deteriorate. On the other hand, when the amount of the acrylic urethane resin component is too large, the blackening resistance tends to decrease. From such a viewpoint, the acrylic urethane-based resin is preferably contained in an amount of 30 parts by mass or more, more preferably 35 parts by mass or more and 40 parts by mass or less. Here, the non-volatile resin component of the acrylic urethane-based resin aqueous dispersion is the above-described acrylic urethane-based resin, and the non-volatile resin component can be measured by a method known in the technical field of aqueous dispersions, For example, the evaporation residue when the aqueous dispersion is heated at 100 ° C. to 130 ° C. for 1 to 3 hours.

  For example, when the surface-treated metal plate is subjected to severe deep drawing as in the case of manufacturing a motor case, the above-mentioned blackening phenomenon is caused by mold sliding or frictional heat between the mold and the metal plate. It is thought that this occurs when the film on the surface of the metal plate is scraped off and peeled off or softened and adheres black to the sliding surface of the product. In addition, the peeled film (resin component) is partially mixed with zinc powder and press oil peeled from the galvanized layer, and as a result of kneading these, a blackened product is generated and adheres to the mold, and is applied to the product surface. Transcription is also possible.

  If the softening point of the acrylic urethane resin is 120 ° C or higher, the occurrence of the blackening phenomenon can be suppressed. Therefore, in the case of a surface-treated metal plate for particularly severe deep drawing applications, the acrylic urethane has a softening point of 120 ° C or higher. It is preferable to use a resin. The mold temperature during deep drawing is estimated to have risen to about 120 ° C due to friction, etc., and the blackening phenomenon cannot be sufficiently suppressed with acrylic urethane resins having a softening point of less than 120 ° C. Because.

  The softening point of the resin is measured by thermomechanical analysis (TMA). In the present invention, “TMA / SS120” (manufactured by Seiko Instruments Inc.) was used. The measurement temperature range was from room temperature (about 25 ° C.) to 250 ° C., and the penetration was performed in an air stream at a heating rate of 5 ° C./min, a measurement load of 5 gf, and an argon gas of 100 ml / min. In the case of obtaining a measurement sample from an aqueous resin dispersion, a sample obtained by placing the water dispersion in a polytetrafluoroethylene dish and drying it for 12 hours or more with a dryer at 40 ° C. was used.

  Further, in order to further reduce the occurrence of the blackening phenomenon, it is necessary to reduce the amount of film peeling at the time of press working and suppress the adhesion to the product. For this reason, it is preferable that the film on the metal plate has a higher hardness. In the present invention, the sword rocker hardness of the acrylic urethane resin film is preferably 25 or more. By hardening the acrylic urethane resin and increasing the hardness of the coating, damage to the coating during mold sliding is reduced, and even if the coating peels off, the peeled coating itself is hard, The effect that the transfer to the product is suppressed appears.

  From such a viewpoint, in the present invention, it is preferable to use an acrylic urethane resin having a softening point of 120 ° C. or higher and a pseudo rocker hardness of 25 or higher.

  Sword rocker hardness is a hardness specified in ASTM D2134-93, and is based on a Sword rocker hardness meter (manufactured and sold by numerous foreign companies in addition to Ueshima Seisakusho (currently discontinued) and Tester Sangyo). Measured. It was also specified in JIS K 5400-1959 (currently abolished). Briefly, a pendulum (sword rocker) is shaken on a sample on which a resin film or the like is formed, and the number of swings until the pendulum reaches a certain swing width is counted to obtain the hardness. In the case of a hard material, the vertical force (self-weight of the rocker) acting downward on the film and the repulsive force (upward) of the film against the rocker balance and do not disturb the left and right repetitive movements, so the number of times until the pendulum stops is increased. In a soft material, since the repulsive force is smaller than the normal force, the left and right repetitive motions are prevented, and the number of times until the pendulum stops is reduced.

  The pseudo rocker has a structure as shown in FIGS. 1 to 3 and is configured to be able to roll and reciprocate between two parallel wheels of the same shape and size. FIG. 4 shows a side view during measurement. A concave portion is formed in a rectangular parallelepiped shape at the center portion of the test plate of the test plate fixing device, and the test plate is placed on the bottom surface of the concave portion, and the sword rocker can be rolled thereon.

  A specific measurement method based on JIS K 5400-1959 will be described. First, place the pseudo rocker on a horizontal surface and adjust with the weight for vertical stabilization so that the vertical axis is vertical. Set a standard glass plate on the test plate fixing device, fix it with the test plate fixing device, place a level on the plate surface, and adjust the height with the adjusting feet of the fixing device so that it is horizontal in the vertical and horizontal directions. Adjust. Place a rock rocker on the test plate, apply a rolling motion, cover with a windshield, and observe the state of the level from outside the windshield. The time when the hour of Sudoku rocker's level B is hidden behind B's oyster is not counted as 0 (start). Thereafter, the count is incremented by 1 for each reciprocation of the rolling motion, and is counted until the millet of the level C is hidden behind the oil and disappears for the first time, and this value is used as the pseudo rocker value. Since the standard glass plate has a pseudo rocker value of 50, the inclination of each of the spirit levels B and C is adjusted so that the pseudo rocker value becomes 50 ± 1 after five measurements. Also, the vertical position of the period adjusting weight is adjusted so that the time required for 50 ± 1 reciprocation is 60 ± 5 seconds. Next, the test plate is changed to a standard methacryl methyl plate (polymethyl methacrylate), and the inclination of each of the level levels B and C is adjusted so that the five rocker lock values are 20 ± 1. This is repeated, and when the measured values of both standard plates satisfy the above-mentioned standard, the spirit levels B and C are fixed. The ambient temperature is 20 to 23 ° C., and the humidity is 20 to 40% RH. The test plate is changed to a sample for which the pseudo rocker is to be measured, and the pseudo rocker value is measured in the same manner as described above. With n = 5, the pseudo rocker value is measured for each, and the average of three of the five pseudo rocker values is determined as the final value. The final value as it is is the Sword Rocker value of the sample, and the value obtained by doubling this is the Sword Rocker hardness. In this invention, it measured using the film | membrane which apply | coated the acrylic urethane type resin adjusted to solid content concentration 20 mass% with the # 20 bar coater on the glass plate, and was dried at 0-105 degreeC.

(1-3) Silica Particles The resin composition for forming a film used in the present invention is 50 parts by mass or more, preferably 60 parts by mass or more of silica particles with respect to 30 to 50 parts by mass of the acrylic urethane resin described above. And it is 70 mass parts or less, Preferably it contains 65 mass parts or less (however, the total amount of an acrylic urethane type resin component and a silica particle shall be 100 mass parts).

  The silica particles impart corrosion resistance and paintability to the resulting resin film, and increase the hardness of the film to improve deep drawing workability. When the content of silica particles is less than 50 parts by mass, the deep drawing processability tends to decrease. On the other hand, when the content of silica exceeds 70 parts by mass, the film forming property of the resin film is lowered, and the corrosion resistance tends to be lowered.

  In order to maximize the effect of the silica particles, the average particle size of the silica particles is preferably in the range of 4 to 20 nm. The smaller the average particle size of the silica particles, the better the corrosion resistance of the resin film. However, when the average particle size is less than about 4 nm, the effect of improving the corrosion resistance tends to be saturated, and the stability of the aqueous resin dispersion is improved. This is because it tends to decrease and gel easily. On the other hand, when the average particle diameter of the silica particles exceeds 20 nm, the film-forming property of the resin film is lowered, and the corrosion resistance and paintability tend to be lowered.

  In addition, as a measuring method of the average particle diameter of a silica particle, it is preferable to employ | adopt a Sears method (4-6 nm) or a BET method (4-20 nm).

  The silica particles that can be used in the film-forming resin composition according to the present invention are preferably those generally known as colloidal silica, such as “Snowtex (registered trademark)” series (colloidal manufactured by Nissan Chemical Industries, Ltd.). “XS”, “SS”, “40”, “N”, “UP” and the like of silica) are preferably used.

(1-4) Silane coupling agent The resin composition for film formation used by this invention contains a silane coupling agent. The silane coupling agent contributes to the improvement of the adhesion between the metal plate and the resin film formed on the metal plate, in addition to the improvement of the corrosion resistance, deep drawing workability, paintability and the like.

  The content of the silane coupling agent in the film-forming resin composition is 5 parts by mass or more, preferably 7 with respect to 100 parts by mass in total of the acrylic urethane resin (nonvolatile resin component) and the silica particles. It is not less than 25 parts by mass, preferably not more than 20 parts by mass. When there is too little content of a silane coupling agent, the reactivity of the acrylic urethane type resin mentioned above and silica particles etc. will fall, and corrosion resistance, paintability, deep drawing workability, etc. will fall. On the other hand, if the content of the silane coupling agent is too large, a gel-like product is produced and the stability of the aqueous resin dispersion described later decreases, or the amount of the silane coupling agent that does not contribute to the reaction increases. The adhesion of the resin film formed on the metal plate may be reduced.

  As said silane coupling agent, it is preferable to use the silane coupling agent of Chemical formula (1).

In the above chemical formula (1), R ¹ represents a glycidoxy group or an epoxycyclohexyl group, R ² and R ³ represent a lower alkoxy group, R ⁴ represents a lower alkoxy group or a lower alkyl group, and X represents a lower alkylene group. Here, “lower” means having 1 to 5 carbon atoms, more preferably 1 to 3 carbon atoms.

  By containing the silane coupling agent, the paintability of the aqueous resin dispersion and the corrosion resistance of the resulting surface-treated metal plate are enhanced. Examples of the silane coupling agent having a glycidoxy group or an epoxycyclohexyl group at the terminal represented by the chemical formula (1) include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, and vinyl. -Tris (β-methoxyethoxy) silane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and the like. A silane coupling agent having a glycidoxy group or an epoxycyclohexyl group is rich in cross-linking reactivity with acrylic urethane resins. Therefore, the resin film obtained by using such a silane coupling agent is strengthened, resulting in corrosion resistance and depth. Drawing workability is improved.

(1-5) Other additives In the present invention, in order to form a stronger film, polymer chains may be cross-linked by chemical bonding utilizing a reaction between functional groups. The crosslinking agent used for the crosslinking formation between the polymer chains is not particularly limited as long as it is a crosslinking agent having two or more functional groups capable of reacting with a carboxyl group in one molecule. For example, sorbitol polyglycidyl ether, ( Poly) glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, trimethylolpropane polyglycidyl ether, neopentyl glycol diglycidyl ether, polyglycidyl ethers such as (poly) ethylene glycol glycidyl ether, and glycidyl such as polyglycidyl amines Group-containing crosslinking agent; 4,4-bis (ethyleneiminecarbonylamino) diphenylmethane, N, N-hexamethylene-1,6-bis (1-aziridinecarboxamide), N, N-diphenylmethane-4,4-bis ( -Aziridinecarboxamide), bifunctional aziridine compounds such as toluenebisaziridinecarboxyamide; tri-1-aziridinylphosphine oxide, tris [1- (2-methyl) aziridinyl] phosphine oxide, trimethylolpropane tris (β- Aziridinylpropionate), tris-2,4,6- (1-aziridinyl) -1,3,5-triazine, tetramethylpropanetetraaziridinylpropionate, etc. Preferred examples include aziridinyl group-containing crosslinking agents such as derivatives thereof, and one or more of them can be used.

  The crosslinking agent is used in a ratio of 1 part by mass or more, more preferably 5 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, with respect to 100 parts by mass of the acrylic urethane resin. It is preferable. If the amount of the crosslinking agent used is too small, the effect of crosslinking by chemical bonding (corrosion resistance due to the formation of a strong film, the effect of improving deep drawing processability) cannot be obtained sufficiently. As a result, the stability of the aqueous resin dispersion may decrease.

  Further, the resin film-forming composition may contain a lubricant as long as the corrosion resistance, deep drawing processability and the like are not deteriorated. Examples of the lubricant include solid lubricants such as polyethylene wax, oxidized polyethylene wax, oxidized polypropylene wax, carnauba wax, paraffin wax, montan wax, rice wax, Teflon (registered trademark) wax, carbon disulfide, and graphite. One or more of these solid lubricants can be selected and used.

(2) Preparation of resin aqueous dispersion and method for forming resin film In the production of the surface-treated metal plate (resin film) of the present invention, the resin composition for film formation is dispersed in water or a solvent containing water as a main component. An aqueous resin dispersion is used. In the aqueous resin dispersion used in the present invention, in order to improve the formation of the resin coating film and the physical properties of the resulting film, the solvent, anti-skinning agent, and leveling agent are used within the range not impairing the object of the present invention. An antifoaming agent, a penetrating agent, an emulsifier, a film-forming aid, a color pigment, a thickener, a lubricant, and the like may be contained.

  The method for preparing the aqueous resin dispersion is not particularly limited, and silica particles, a silane coupling agent, and a crosslinking agent, a lubricant, and the like used as necessary in the aqueous dispersion of the acrylic urethane resin. It is obtained by blending a predetermined amount of the additive. Silica particles, silane coupling agents, lubricants, crosslinking agents, etc. may be added at any stage, but after the addition of silane coupling agents and crosslinking agents, the crosslinking reaction proceeds and gelation does not occur. Thus, it is desirable not to apply heat. For example, the aqueous resin dispersion is preferably stored at 25 ° C. or lower. Further, the viscosity of the aqueous resin dispersion is not particularly limited, and a preferable viscosity can be appropriately adopted depending on the forming method and the like.

  The method for forming the resin film on the metal plate is not particularly limited, and a conventionally known coating method can be employed.For example, the resin aqueous dispersion can be used using a roll coater method, a spray method, a curtain flow coater method, etc. What is necessary is just to apply | coat to the single side | surface or both surfaces of the metal plate surface, and to heat-dry. The heating and drying temperature is not particularly limited, but when a crosslinking agent is used, it is preferable to employ a temperature at which the crosslinking reaction of the crosslinking agent used proceeds. Further, when polyethylene wax is used as the lubricant, if the wax maintains a spherical shape, the workability in the subsequent processing step becomes good. Therefore, it is preferable to perform heat drying so that the temperature of the metal plate is in the range of 70 to 130 ° C. so that the spherical shape is not impaired. If the temperature of the metal plate during application of the aqueous resin dispersion is high, the components in the aqueous resin dispersion react with the metal plate until the coating film is dried, or moisture is evaporated before drying, resulting in uneven appearance. Therefore, the temperature of the metal plate at the time of applying the resin aqueous dispersion is preferably 50 ° C. or less.

  The azomethine cross-linked structure is formed by removing (volatilizing) alkali components used for neutralization of moisture and resin components if a functional group capable of forming azomethine cross-links is present in the film at the time of resin film formation. A cross-linking reaction proceeds to form. Therefore, under such conditions, azomethine crosslinks are generated regardless of temperature.

  The metal plate used in the present invention is not particularly limited, but is preferably a zinc-based plated steel plate, for example, a hot-dip galvanized steel plate, an alloyed hot-dip galvanized steel plate, a zinc-5% aluminum-plated steel plate, Zinc-55% aluminized steel sheet, electro-pure galvanized steel sheet, electro-zinc-nickel-plated steel sheet, aluminum plate, titanium plate and the like can be suitably used. In addition, before forming the resin film, the surface of the metal plate may be subjected to a treatment with Co or Ni, an inhibitor treatment, or various chromate-free and hexavalent chromate-free ground treatments.

Adhesion amount of the resin film to the metal plate (thickness), after drying, 0.05 g / m ² or more, more preferably be at 0.2 g / m ² or more, 1 g / m ² or less, more preferably 0 It is desirable that it is 0.7 g / m ² or less. When there is too little adhesion amount, corrosion resistance will deteriorate. On the other hand, when the adhesion amount is too large, the blackening resistance tends to deteriorate.

Usually, in FT-IR measurement, a peak derived from azomethine crosslinking is observed in the vicinity of 1660 cm ^−1, but the resin film according to the present invention includes a urethane bond in which the peak is confirmed in the same region. It is difficult to clearly distinguish these by -IR. However, for example, when a FT-IR measurement is performed on a sample prepared under the same conditions using a resin that includes a urethane bond but does not include an azomethine crosslink, the resin film according to the present invention has a 1660 cm thickness compared to the sample. A peak around ^-1 is amplified and confirmed.

  In addition, although it is difficult to quantify the abundance of azomethine crosslinks in the resin film as described above, for example, the abundance (theoretical value) of azomethine crosslinks calculated from the amount charged at the time of acrylic urethane resin production is The total amount of polyurethane and (meth) acrylic polymer is preferably 5 to 120 meq, more preferably 10 to 90 meq.

  In addition, the surface-treated metal plate of the present invention may be used as it is after obtaining a processing step according to the application, or used after being subjected to electrodeposition coating, powder coating, silk printing or the like under conventional conditions. May be.

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range. The evaluation methods employed in the examples are as follows.

(1) Corrosion resistance The obtained surface-treated metal sheet (resin-coated steel sheet) was subjected to a salt spray test on a flat plate with an edge seal according to JIS-Z2371 (11.1 neutral salt spray test). In addition, the time until the amount of white rust generated reached 5% of the area of the flat plate was evaluated.
(Evaluation criteria)
◎: White rust generation 240 hours or more ○: White rust generation 120 hours to less than 240 hours Δ: White rust generation 72 hours to less than 120 hours ×: White rust generation less than 72 hours

(2) Deep drawing workability About the obtained surface-treated metal plate (resin-coated steel plate), a press-molded product is produced with an 80-ton crank press device (manufactured by Aida Engineering Co., Ltd., 80TON crank press, see FIG. 5) and molded. The galling of the sliding surface of the product and the blackening phenomenon (blackening resistance) were visually observed and evaluated.

<Press molding conditions>
・ Wrinkle holding pressure = 9.8N
-Molding speed = 40 SPM
・ Bead height = 3mm
・ Mizo R (r4) = 2mm
・ Die R (r3) = 0.5mm
-Die diameter: 51.640 mm
-Punch diameter: 50.120 mm

(Evaluation criteria for mold galling)
A: The area of the galling portion is less than 40% of the whole.
○: The area of the portion where galling occurs is 40% or more and less than 60% of the whole.
Δ: The area of the galling portion is 60% or more and less than 80% of the whole.
X: The area of the galling part is 80% or more of the whole.

(Evaluation criteria for blackening phenomenon)
A: No blackening phenomenon was observed on the sliding surface of the press-formed product (very good).
○: Good (see FIG. 6A).
Δ: Bad.
X: Extremely bad (see FIG. 6B).

(3) Paintability To the obtained surface-treated metal plate (resin-coated steel plate), a melamine alkyd paint (“Amirac (registered trademark) # 1000” manufactured by Kansai Paint Co., Ltd.) is applied, and the coating thickness after drying is about 20 μm. After spray coating, baking was performed at 130 ° C. for 20 minutes for post-coating. Subsequently, after immersing this test material in boiling water for 1 hour, taking it out and leaving it to stand at room temperature (25 ° C.) for 1 hour, the surface of the test material was cut into 100 mm squares of 1 mm square with a cutter knife, A tape peeling test (JIS K5600, the tape used was “Cello Tape (registered trademark) No. 405” manufactured by Nichiban Co., Ltd.) was applied to this, and the coating film adhesion was evaluated according to the following four levels according to the number of remaining squares of the coating film. Evaluated by criteria.
(Evaluation criteria)
◎: Residual rate 95% or more ○: Residual rate 80% or more and less than 95% △: Residual rate 70% or more and less than 80% ×: Residual rate less than 70%

(4) Hardness Sword Locker Hardness An aqueous sample dispersion of each resin obtained in the following production examples was applied to a 200 mm long and 150 mm wide glass plate with a # 20 bar coater to prepare a sample for evaluation. By the above-described method, the pseudo rocker value of the resin film was measured to obtain the pseudo rocker hardness.

(5) Softening point of resin film The softening point of the resin film was measured by thermomechanical analysis (TMA: “TMA / SS120”: manufactured by Seiko Instruments Inc.). The sample was prepared by placing an appropriate amount of an aqueous dispersion of resin in a dish made of polytetrafluoroethylene and drying it with a dryer at 40 ° C. for 12 hours or more. The measurement temperature range was from room temperature to 250 ° C., and the penetration rate was 5 ° C./min, the measurement load was 5 gf, and the argon gas was 100 ml / min.

[Preparation of resin aqueous dispersion]
Production Example 1 Preparation of Acrylic Urethane Resin Aqueous Dispersion 1 (H-MDI Urethane Acrylic Resin)
Polyester polyol 24.3g ("TA22-" consisting of dimer acid, trimethylolpropane and diethylene glycol as polyol components was added to a pressurization-compatible synthesizer equipped with a stirrer, heater for heating, thermometer and temperature controller. 636 "(manufactured by Hitachi Chemical Co., Ltd.), 3.89 g of 1,4-cyclohexanedimethanol, 22.52 g of dimethylolpropionic acid, and 8.82 g of dihydroxyacetone (manufactured by Merck Ltd., Japan). The reaction system is uniformly dispersed by adding 96.01 g of a reaction solvent in which 370.01 g of butyl acid, 370.01 g of n-butyl methacrylate, 13.32 g of diacetone acrylamide, 13.32 g of methyl ethyl ketone and 1.51 g of methoquinone are added. Was stirred as such.

  Next, after adjusting the mixed solution of the polyol and the acrylic monomer to 20 ° C., 128.81 g of hexamethylene diisocyanate (H-MDI) is added as an isocyanate component, and then 0.12 g of dibutyltin dilaurate. Was added. After completion of the exotherm, the reaction solution was heated to 90-95 ° C. over 1 hour and reacted for 2.5 hours. Thereafter, the reaction solution was cooled to 50 ° C., 96.01 g of the reaction solvent containing the acrylic monomer was introduced into the synthesizer, and stirred at 50 ° C. for 1 hour to obtain an acrylic monomer-containing prepolymer. The isocyanate group (NCO) content (%) of the obtained prepolymer was 3.9% (theoretical value 3.96%; NCO / OH ratio 1.58).

  After heating 250 g of the acrylic monomer-containing prepolymer to 50 ° C., 11.18 g of triethylamine was added to neutralize the carboxyl group. To this neutralized acrylic monomer-containing prepolymer, 45.64 g of an anionic surfactant (“Arscope TH-330” (aqueous solution of 27% active ingredient): manufactured by Toho Chemical Co., Ltd.) and ion-exchanged water 358 .94 g mixed with 1.23 g of a water-soluble azo polymerization initiator (“VA-044”, manufactured by Wako Pure Chemical Industries, Ltd.) was introduced over 15 minutes, and after confirming that heat generation was completed, A chain extension reaction was performed by adding an aqueous hydrazine solution in which 7.25 g of 80% hydrazine monohydrate was diluted with 72.54 g of ion-exchanged water. After completion of the addition of the hydrazine aqueous solution, the mixture was stirred at 65 ° C. for 60 minutes. Thereafter, 0.1 g of “KS-530” (manufactured by Shin-Etsu Chemical Co., Ltd., foam suppressor) was added to obtain dispersion 1.

  After 300.00 g of the above dispersion 1 was heated to 50 ° C., 152.04 g of the reaction solvent in which the above acrylic monomer was mixed with this dispersion 1, and 274.02 g of ion-exchanged water, water-soluble azo polymerization was started. A polymerization initiator aqueous solution mixed with 1.49 g of an agent (“VA-044”, manufactured by Wako Pure Chemical Industries, Ltd.) was introduced over 45 minutes and stirred at 55 ° C. to 60 ° C. for 4 hours. Next, an aqueous solution in which 3.87 g of adipic acid dihydrazide was dissolved in 7.19 g of ion-exchanged water was added thereto, and the mixture was stirred at 55 ° C. to 60 ° C. for 3 hours. A resin aqueous dispersion 1 was obtained.

Production Example 2 Preparation of Acrylic Urethane Resin Water Dispersion 2 A dimer acid, trimethylolpropane as a polyol component was added to a 1.0 L pressurizing synthesizer equipped with a stirrer, a heater for heating, a thermometer, and a temperature controller. Polyester polyol 24.3 g ("TA22-636" manufactured by Hitachi Chemical Co., Ltd.), 1,4-cyclohexanedimethanol 3.89 g, dimethylolpropionic acid 22.52 g, dihydroxyacetone 8.82 g (Merck Ltd., JAPAN), and a reaction solvent 96 in which 370.01 g of butyl acrylate, 370.01 g of n-butyl methacrylate, 13.32 g of diacetone acrylamide, 13.32 g of methyl ethyl ketone, and 1.51 g of methoquinone were mixed. Add .01g In addition, stirring was performed so that the entire system was uniformly dispersed.

  Next, after adjusting the mixed solution of the polyol and the acrylic monomer to 20 ° C., 128.81 g of dicyclohexylmethane-4,4′-diisocyanate was added as an isocyanate component, and then dibutyltin dilaurate was added in an amount of 0.8. 12 g was added. After completion of the exotherm, the reaction solution was heated to 90-95 ° C. over 1 hour and reacted for 2.5 hours. Thereafter, the reaction solution was cooled to 50 ° C., 96.01 g of the reaction solvent containing the acrylic monomer was introduced into the synthesizer, and stirred at 50 ° C. for 1 hour to obtain an acrylic monomer-containing prepolymer. The isocyanate group (NCO) content (%) of the obtained prepolymer was 3.9% (theoretical value 3.96%; NCO / OH ratio 1.58).

  After heating 250 g of the acrylic monomer-containing prepolymer to 50 ° C., 11.18 g of triethylamine was added to neutralize the carboxyl group. To this neutralized acrylic monomer-containing prepolymer, 45.64 g of an anionic surfactant (“Arscope TH-330” (aqueous solution of 27% active ingredient): manufactured by Toho Chemical Co., Ltd.) and ion-exchanged water 358 .94 g mixed with 1.23 g of a water-soluble azo polymerization initiator (“VA-044”, manufactured by Wako Pure Chemical Industries, Ltd.) was introduced over 15 minutes, and after confirming that heat generation was completed, A chain extension reaction was performed by adding an aqueous hydrazine solution in which 7.25 g of 80% hydrazine monohydrate was diluted with 72.54 g of ion-exchanged water. After completion of the addition of the hydrazine aqueous solution, the mixture was stirred at 65 ° C. for 60 minutes. Thereafter, 0.1 g of “KS-530” (manufactured by Shin-Etsu Chemical Co., Ltd., foam suppressor) was added to obtain dispersion 2.

  After 300.00 g of the above dispersion 2 was heated to 50 ° C., 152.04 g of the reaction solvent in which the above acrylic monomer was mixed with this dispersion 2, and 274.02 g of ion-exchanged water, water-soluble azo polymerization was started. A polymerization initiator aqueous solution mixed with 1.49 g of an agent (“VA-044”, manufactured by Wako Pure Chemical Industries, Ltd.) was introduced over 45 minutes and stirred at 55 ° C. to 60 ° C. for 4 hours. Next, an aqueous solution in which 3.87 g of adipic acid dihydrazide was dissolved in 7.19 g of ion-exchanged water was added thereto, and the mixture was stirred at 55 ° C. to 60 ° C. for 3 hours. A resin aqueous dispersion 2 was obtained.

Production Example 3 Preparation of Aqueous Dispersion of Carboxyl Group-Containing Polyurethane Resin A polytetramethylene ether glycol 60 g (average molecular weight 1000) was added as a polyol component to a synthesis apparatus having an internal volume of 0.8 L equipped with a stirrer, a heater for heating, a thermometer, and a temperature controller , Produced by Hodogaya Chemical Co., Ltd.), 14 g of 1,4-cyclohexanedimethanol, and 20 g of dimethylolpropionic acid were added, and 30.0 g of N-methylpyrrolidone was added as a reaction solvent. Tolylene diisocyanate 104g was added here as an isocyanate component, and this mixed solution was heated up to 80-85 degreeC, and was made to react for 5 hours. The obtained prepolymer had an NCO content of 8.9%.

  16 g of triethylamine was further added to this prepolymer, emulsified at 50 ° C. for 4 hours, and chain extension reaction was performed to obtain a carboxyl group-containing polyurethane resin aqueous dispersion.

Production Example 4 Preparation of Ethylene-Unsaturated Carboxylic Acid Copolymer Aqueous Dispersion In an autoclave having an emulsification facility with an internal capacity of 0.8 L equipped with a stirrer, a heater for heating, a thermometer, and a temperature controller, 626 parts by mass of water, ethylene -Acrylic acid copolymer (acrylic acid 20 mass%, melt index (MI): 1300, mass average molecular weight (Mw): 20,000, acid value: 150, "Primacol (registered trademark) 5990I" manufactured by Dow Chemical Co., Ltd. ) In addition to 160 parts by mass, 0.6 equivalent of triethylamine and 0.15 equivalent of sodium hydroxide are added to the total carboxyl group of the ethylene-acrylic acid copolymer, and the atmosphere is 150 ° C. and 0.5 MPa. Under high speed stirring, the reaction solution was cooled to 40 ° C. to obtain an aqueous dispersion of an ethylene-acrylic acid copolymer.

  To the aqueous dispersion obtained above, 4,4-bis (ethyleneiminocarbonylamino) diphenylmethane ("Chemite (registered trademark) DZ-22E", manufactured by Nippon Shokubai Co., Ltd.) was used as the crosslinking agent. It added so that it might become a ratio of 5 mass parts with respect to 100 mass parts of non-volatile resin components of a copolymer, and the ethylene-unsaturated carboxylic acid copolymer aqueous dispersion was obtained.

Production Example 5 Preparation of Aqueous Dispersion Containing Mainly Ethylene-Acrylic Acid Copolymer Ethylene-acrylic in an autoclave having an internal capacity of 1.0 L equipped with a stirrer, a heater for heating, a thermometer, and a temperature controller 200 parts by weight of an acid copolymer (the above “Primacol (registered trademark) 5990I”), an aqueous polymaleic acid solution (“NOPOL (registered trademark) PMA-50W” manufactured by NOF Corporation), Mw: about 1100 (polystyrene conversion), solid content 50% by mass) 8.0 parts by mass, 33.5 parts by mass of triethylamine (0.63 equivalents based on the total carboxyl groups of the ethylene-acrylic acid copolymer), 48% aqueous sodium hydroxide solution 6.9 Parts by mass (0.15 equivalents based on the total carboxyl groups of the ethylene-acrylic acid copolymer), tall oil fatty acid (harimatized) "Hartol FA3" manufactured by the company) 3.5 parts by mass and 792.6 parts by mass of ion-exchanged water were added and sealed, and the reaction solution was stirred at 500 rpm for 3 hours at 150 ° C and 0.5 MPa (5 atm). Cooled to ° C. Next, 10.4 parts by mass of a silane coupling agent (Momentive Performance Materials (former name: GE Toshiba Silicone) “TSL8350”, γ-glycidoxypropyltrimethoxysilane), polycarbodiimide (Nisshinbo “Carbodilite”) (Registered trademark) SV-02 ", Mw: 2,700, solid content 40% by mass) 31.2 parts by mass and 72.8 parts by mass of ion-exchanged water were added and stirred for 10 minutes. An aqueous dispersion mainly composed of an ethylene-acrylic acid copolymer was obtained.

[Resin softening point and Sword rocker hardness]
(Experimental example 1)
Acrylic urethane resin aqueous dispersions 1 and 2 obtained in Production Examples 1 to 5, carboxyl group-containing polyurethane resin aqueous dispersions, ethylene-unsaturated carboxylic acid copolymer aqueous dispersions, and ethylene-acrylic acid copolymers The softening point and the Sword rocker hardness of the resin film were measured using an aqueous dispersion mainly composed of. The results are shown in Table 1.

[Preparation of aqueous film-forming resin dispersion and preparation of surface-treated metal sheet]
(Experimental example 2)
Acrylic urethane resin aqueous dispersions 1 and 2 obtained in each of the above production examples, a mixed solution of a carboxyl group-containing polyurethane resin aqueous dispersion, an ethylene-unsaturated carboxylic acid copolymer aqueous dispersion, and an ethylene-acrylic acid copolymer. Silica particles ("Snowtex (registered trademark) XS" manufactured by Nissan Chemical Co., Ltd., average particle diameter of 4 to 6 nm) are blended with each of the aqueous dispersions mainly composed of a polymer according to the blending composition shown in Table 2. A total of 100 parts by mass in terms of nonvolatile components was added, and 10 parts by mass of γ-glycidoxypropyltrimethoxysilane (“KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) was added as a silane coupling agent. An aqueous resin dispersion for film formation was prepared.

These film-forming resin aqueous dispersions are applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to obtain a resin film having an adhesion amount of 0.4 g / m ² . A surface-treated metal plate (resin-coated steel plate) was obtained. The resulting resin-coated steel sheet was evaluated for corrosion resistance and deep drawing workability. The results are also shown in Table 2. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

  In Table 2, AU1 is the nonvolatile resin component of the acrylic urethane resin aqueous dispersion 1, AU2 is the nonvolatile resin component of the acrylic urethane resin aqueous dispersion 2, and PU is the carboxyl group-containing polyurethane resin aqueous dispersion. Non-volatile resin component of the body, EC is the non-volatile resin component of the ethylene-unsaturated carboxylic acid copolymer aqueous dispersion, and EA is the non-volatile resin of the aqueous dispersion mainly comprising the ethylene-acrylic acid copolymer Each component is shown.

  Steel plate No. 1-No. 3 is the same as that of Production Example 1 in which the acrylic urethane-based resin aqueous dispersion 1 is a steel plate no. 4-No. 6 is a surface-treated metal plate having a resin film formed by using each of the acrylic urethane-based resin aqueous dispersion 2 of Production Example 2. From the results in Table 2, it can be seen that these steel sheets are excellent in corrosion resistance and deep drawing workability.

  On the other hand, the steel plate No. Nos. 7 to 9 are those using the carboxyl group-containing polyurethane resin aqueous dispersion of Production Example 3. Nos. 10 to 12 were prepared by mixing the carboxyl group-containing polyurethane resin aqueous dispersion of Production Example 3 and the ethylene-unsaturated carboxylic acid copolymer aqueous dispersion of Production Example 4. The steel plate No. Compared with 1-6, all of these steel plates were inferior in blackening resistance. This is considered because the acrylic resin was not contained in the resin film, and sufficient film hardness was not obtained.

  Steel plate No. Nos. 13 to 15 are ethylene-unsaturated carboxylic acid copolymer aqueous dispersions of Production Example 4, steel plate Nos. 16-18 respectively use the aqueous dispersion which has the ethylene-acrylic acid copolymer of the manufacture example 5 as a main component. The steel plate No. Compared with 1-6, all of these steel plates were inferior in blackening resistance. This is probably because the softening point of the resin is low.

(Experimental example 3)
Acrylic urethane resin aqueous dispersion 1 obtained in Production Example 1 or acrylic urethane resin aqueous dispersion 2 obtained in Production Example 2 and silica particles ("Snowtex (registered trademark) XS" manufactured by Nissan Chemical Industries, average particle) In accordance with the composition shown in Table 3, so that the total of both in terms of non-volatile components is 100 parts by mass, where γ-glycidoxy is used as the silane coupling agent. 10 parts by mass of propyltrimethoxysilane (“KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) was added to prepare an aqueous resin film-forming dispersion.

This film-forming resin aqueous dispersion is applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to form a resin film having an adhesion amount of 0.4 g / m ^2. A surface-treated metal plate (resin-coated steel plate) was obtained. The resulting resin-coated steel sheet was evaluated for corrosion resistance and deep drawing workability. The results are shown in Table 3. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

  Steel plate No. 24-No. 28 is a steel plate No. 28 from the acrylic urethane resin aqueous dispersion 1 of Production Example 1. 37-No. 41 is a surface-treated metal plate provided with a resin film obtained from the acrylic urethane-based resin aqueous dispersion 2 of Production Example 2, and the film-forming resin aqueous dispersion is an acrylic urethane-based resin aqueous dispersion 30 to 30 50 parts by mass (in terms of nonvolatile resin component) and 50 to 70 parts by mass of silica particles are contained in a total of 100 parts by mass, and further 10 parts by mass of the silane coupling agent with respect to the total of 100 parts by mass. It is contained in the ratio. All of these steel plates were excellent in corrosion resistance and deep drawability.

  On the other hand, the steel plate No. 19-No. 23 and no. 32-No. No. 36 is an example in which the amount of the acrylic urethane resin contained in the aqueous film-forming resin dispersion is small. 24-28 and no. 37-No. It was inferior in corrosion resistance compared to 41 steel plates. Steel plate No. 29-No. 31 and no. 42-No. No. 44 is an example in which the amount of the nonvolatile resin component is too large. 24-28 and no. 37-No. The blackening resistance was inferior to that of the 41 steel plate.

(Experimental example 4)
The acrylic urethane resin aqueous dispersion 1 or 2 obtained above and silica particles (“Snowtex (registered trademark) XS” manufactured by Nissan Chemical Industries, Ltd., average particle diameter 4 to 6 nm) are dispersed in an acrylic urethane resin aqueous dispersion. The non-volatile resin component is 40 parts by mass and the silica particles are 60 parts by mass, and the silane coupling agent (γ-glycidoxypropyltrimethoxysilane, Shinetsu) is added to 100 parts by mass in total. Chemical industry “KBM403”) was added in an amount of 0 to 30 parts by mass to prepare a film-forming resin aqueous dispersion.

This film-forming resin aqueous dispersion is applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to form a resin film having an adhesion amount of 0.4 g / m ^2. The formed surface-treated metal plate (resin-coated steel plate) was obtained.

The obtained resin-coated steel sheets were evaluated for corrosion resistance, deep drawing workability and paintability. The results are shown in Table 4. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

  Steel plate No. 46-No. No. 51 is a steel plate No. 1 from acrylic urethane resin aqueous dispersion 1. 54-No. 59 is a surface-treated metal plate having a resin film obtained from the acrylic urethane-based resin aqueous dispersion 2, and the film-forming resin aqueous dispersion contains 40 parts by mass (nonvolatile resin) of the acrylic urethane-based resin aqueous dispersion. Component conversion), 60 mass parts of silica particles are contained, and the silane coupling agent is contained at a ratio of 5 to 25 mass parts with respect to 100 mass parts in total. From Table 4, it can be seen that all the steel plates are excellent in corrosion resistance, deep drawing workability, and paintability.

  On the other hand, steel plate No. 45 and no. 53 is an example which does not contain a silane coupling agent. 52 and no. No. 60 is an example in which the content of the silane coupling agent exceeds 25 parts by mass. 46-No. 51 and no. 54-No. Compared to 59 steel plates, all the steel plates were inferior in paintability.

(Experimental example 5)
40 parts by mass of the acrylic urethane resin aqueous dispersion 1 or 2 (in terms of non-volatile resin component) and 60 parts by mass of silica particles having an average particle diameter of 4 to 100 nm (“Snowtex (registered trademark)” XS manufactured by Nissan Chemical Industries) 10 parts by mass of a silane coupling agent (γ-glycidoxypropyltrimethoxysilane, “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by mass in total. An aqueous dispersion was prepared.

This film-forming resin aqueous dispersion is applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to form a resin film having an adhesion amount of 0.4 g / m ^2. The formed surface-treated metal plate (resin-coated steel plate) was obtained. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

  The obtained resin-coated steel sheets were evaluated for corrosion resistance, deep drawing workability, and paintability. The results are shown in Table 5.

  From the results of Table 5, it can be seen that by using silica particles having an average particle diameter of 4 to 20 nm, a surface-treated metal plate excellent in corrosion resistance, deep drawing workability, and paintability can be obtained.

(Experimental example 6)
40 parts by mass (in terms of non-volatile resin component) of the acrylic urethane resin aqueous dispersion 1 or 2 and silica particles (“Snowtex (registered trademark) XS” manufactured by Nissan Chemical Co., Ltd., average particle diameter of 4 to 6 nm) 60 10 parts by mass of various silane coupling agents shown in Table 6 were added to 100 parts by mass in total of both to prepare a film-forming resin aqueous dispersion.

This film-forming resin aqueous dispersion is applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to form a resin film having an adhesion amount of 0.4 g / m ^2. The formed surface-treated metal plate (resin-coated steel plate) was obtained. The obtained resin-coated steel sheets were evaluated for corrosion resistance, deep drawing workability, and paintability. The results are shown in Table 6. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

  From the results of Table 6, it can be seen that by using a silane coupling agent having a glycidoxy group or an epoxycyclohexyl group at the terminal as the silane coupling agent, the aqueous resin dispersion for film formation can be stably maintained (steel plate) No. 69-71 and No. 75-No. 77). In addition, these No. 69-71 and no. 75-No. The 77 steel plate was also excellent in corrosion resistance, deep drawing workability and paintability.

(Experimental example 7)
40 parts by mass (in terms of non-volatile resin component) of the acrylic urethane resin aqueous dispersion 1 or 2 and 60 parts by mass of silica particles (“Snowtex (registered trademark) XS, manufactured by Nissan Chemical Industries, average particle diameter: 4 to 6 nm)” 10 parts by mass of a silane coupling agent (γ-glycidoxypropyltrimethoxysilane, “KBM403” manufactured by Shin-Etsu Chemical Co., Ltd.) is added to 100 parts by mass in total of both, and a film forming resin is added. An aqueous dispersion was prepared.

This film-forming resin aqueous dispersion is applied to the surface of an electropure galvanized steel sheet with a drawing roll, and the coating film is heated and dried at a plate temperature of 90 ° C. to give an adhesion amount of 0.05 to 2.0 g / m ^2. A surface-treated metal plate (resin-coated steel plate) having a resin film was obtained.

The obtained resin-coated steel sheets were evaluated for corrosion resistance, deep drawing workability, and paintability. The results are shown in Table 7. In addition, as the said electropure galvanized steel plate, the electropure galvanized steel plate (Zinc adhesion amount: 20 g / m < ² >, plate | board thickness: 0.8 mm) which does not perform a chromate process was used.

From the results of Table 7, it can be seen that the corrosion resistance, deep drawing workability and paintability of the surface-treated metal plate can be improved by setting the amount of the resin film attached to the surface of the metal plate in the range of 0.05 to 1 g / m ^2. .

  Since the surface-treated metal sheet of the present invention is excellent in corrosion resistance, deep drawing workability and paintability, it is suitable for deep drawing products used in automobiles, home appliances, building materials, etc. such as audio chassis, computer cases, motor cases and pulleys. Preferably used.

It is a front view of a suedo locker. It is a rear view of a pseudo rocker. It is a side view of a pseudo rocker. It is a figure which shows the state which is measuring the pseudo rocker value. It is a figure which shows the processing apparatus used for deep drawing workability evaluation. It is a figure which shows the external appearance of the sliding part of the steel plate after deep drawing.

Claims (7)

A surface-treated metal plate having a resin film on the surface of the metal plate,
The resin film contains 30 to 50 parts by mass of an acrylic urethane resin and 50 to 70 parts by mass of silica particles having an average particle diameter of 4 to 20 nm so that the total of both becomes 100 parts by mass,
It is formed from a film-forming resin composition containing a silane coupling agent in a ratio of 5 to 25 parts by mass with respect to a total of 100 parts by mass of the acrylic urethane resin and silica particles. Surface treatment metal plate.   The acrylic urethane-based resin contains, as a raw material, a polyisocyanate, a polyol, and a dihydroxyalkanoic acid, and a polyurethane obtained from a urethane prepolymer synthesized from 3 to 80 parts by mass in total, and 10 to 97 parts by mass The surface-treated metal sheet according to claim 1, comprising a (meth) acrylic polymer obtained from the (meth) acrylic monomer.   The surface-treated metal sheet according to claim 1 or 2, wherein the acrylic urethane-based resin has a carbonyl group and / or a hydrazine group in the structure of polyurethane and / or (meth) acrylic polymer.   The surface-treated metal sheet according to any one of claims 1 to 3, wherein the acrylic urethane-based resin has a softening point of 120 ° C or higher and a pseudo rocker hardness of 25 or higher.   The surface-treated metal plate according to claim 1, wherein the resin film has an azomethine cross-linked structure. The surface-treated metal plate according to claim 1, wherein the silane coupling agent has a structure represented by the following chemical formula (1).
(In the above chemical formula (1), R ¹ is a glycidoxy group or epoxycyclohexyl group, R ² and R ³ are lower alkoxy groups, R ⁴ is a lower alkoxy group or lower alkyl group, and X is a lower alkylene group.) Surface-treated metal sheet according to any one of claims 1 to 6 adhered amount of the resin film is 0.05 to 1 g / m ^2.