JP2003221686A - Surface-treated metal plate and surface-treatment agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a metal plate having an organic coating film which shows excellent corrosion resistance and wet adhesion and requires no special waste water treatment upon applying a surface treatment agent or using the obtained surface-treated metal plate, and a surface treatment agent suitable for forming the organic coating film. <P>SOLUTION: The surface-treated metal plate has an organic coating film formed from an epoxy resin, a glycoluryl resin and a metal compound on at least one side of a metal plate. The surface treatment agent for this contains an epoxy resin, a glycoluryl resin and a metal compound. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface-treated metal sheet, and more particularly to a surface-treated metal sheet having an organic coating excellent in corrosion resistance and wet adhesion, particularly surface-treated zinc-based plated steel sheet, and formation of the organic coating. The present invention relates to a surface treatment agent suitable for.

[0002]

2. Description of the Related Art Conventionally, galvanized steel sheets such as galvanized steel sheets and zinc-aluminum plated steel sheets have been widely used in the fields of home appliances, automobiles and construction. In order to improve the corrosion resistance of the steel sheet, these steel sheets are used after being subjected to a chromate coating treatment on the plating, or after being subjected to a chromate coating treatment and further provided with an organic film. The chromate film has a very thin film thickness of about 0.01 μm, but it has a so-called self-repairing function, and thus has excellent corrosion resistance, and since it is very thin, it has excellent electrical conductivity. Further, when an organic film is formed on the upper layer, the adhesion with the organic film is good.

However, although the chromate film is excellent in corrosion resistance, conductivity and coating adhesion, it contains hexavalent chromium, and therefore it is necessary to perform special wastewater treatment prescribed by the Water Pollution Control Law in the chromate coating process. However, there is a drawback that the cost is increased. Therefore, in order to prevent the occurrence of white rust on steel sheets, especially zinc-based plated steel sheets, a surface treatment technique that does not use chromium is required, and for example, many proposals have been made as described below.

(A) at least 4 fluorine atoms,
An anion component composed of at least one element such as Ti or Zr (for example, fluorotitanic acid represented by (TiF ₆ ² )), (b) a cation component such as Co or Mg,
A method for surface treatment of a metal comprising a chromium-free composition containing (c) a free acid for pH adjustment and (d) an organic resin (for example, Patent Document 1).

A metal surface treatment method comprising a chromium-free composition containing (a) a hydroxyl group-containing organic resin, (b) phosphoric acid, and (c) a phosphoric acid salt of a metal such as Cu or Co. 2).

(A) a resin having a polyhydroxy ether segment and a copolymer segment of an unsaturated monomer,
A metal surface treatment agent comprising a chromium-free composition containing (b) phosphoric acid and (c) a phosphoric acid compound of a metal such as Cu or Co (for example, Patent Document 3).

(A) Bivalent or higher valent metal ions such as Mn and Co, (b) acids such as fluoroacid and phosphoric acid, (c) silane coupling agent, and (d) water-soluble polymer unit of 2 to 50 A water-soluble surface treatment agent obtained by dissolving a polymer in an aqueous medium (for example, Patent Document 4).

(A) thiocarbonyl group-containing compound,
A method of coating a zinc-coated steel with an aqueous anticorrosive coating agent containing (b) phosphate ions and (c) water-dispersible silica (for example, Patent Document 5).

In the above methods (1) to (3), when the metal plate is coated with a sufficient amount of the surface treatment agent (coating agent, coating agent), that is, when a coating having a sufficient film thickness is applied, the corrosion resistance is reasonable. However, the corrosion resistance was extremely inadequate when, for example, a coating for exposing a part of the convex portion of the metal plate was applied or the film thickness was too thin. That is, if a coating film on a metal plate has a defect or a flaw, corrosion progresses from that portion, resulting in insufficient corrosion resistance.

Further, the sulfur-containing compound such as the thiocarbonyl group-containing compound in the above method is easily adsorbed on the surface of metal such as zinc, and the thiol ion is active at the time of coating due to the synergistic action with the phosphate ion. It is adsorbed on the zinc surface site and exhibits a rust preventive effect.
The zinc-based plated steel sheet obtained by this surface treatment method has high corrosion resistance when the surface is coated with a layer having a thiocarbonyl group-containing compound such as -NCS or -OCS group, but when the thickness of the coating film is reduced. A part not covered with the thiocarbonyl group-containing compound appears, which causes rusting. Further, if a coating film on a metal plate has a defect or a flaw, corrosion progresses from that portion, resulting in insufficient corrosion resistance.

Further, all of the above-mentioned prior arts are based on the idea of firmly adhering the metal surface and the film formed by the surface treatment agent at the interface. Microscopically, because the adhesion between the metal surface and the surface treatment agent is incomplete,
There was a limit to the adhesiveness (wet adhesiveness) in a wet environment.
That is, if there is a damaged portion in the film, there is a problem that rusting occurs in a corrosive environment, and corrosion progresses to the surroundings starting from this.

[0012]

[Patent Document 1] JP-A-5-195244

[Patent Document 2] Japanese Patent Laid-Open No. 9-241856

[Patent Document 3] JP-A-11-50010

[Patent Document 4] JP-A-11-106945

[Patent Document 5] Japanese Patent Laid-Open No. 11-29724

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is stipulated in the Water Pollution Control Act in the step of coating a surface treatment agent and in using the obtained surface-treated galvanized steel sheet. Various organic coatings, including zinc-based plated steel sheets, which have an organic coating with excellent corrosion resistance and wet adhesion, improving the drawbacks of conventional surface-treated zinc-based plated steel sheets without the need for special wastewater treatment. It is an object of the present invention to provide a metal plate having: and a surface treatment agent suitable for forming the organic film.

[0014]

Therefore, the first aspect of the present invention is to provide a surface-treated metal plate having an organic film formed of an epoxy resin, a glycoluril resin and a metal compound on at least one surface of the metal plate. Is.

The preferred present invention is the surface-treated metal plate, wherein the epoxy resin is a bisphenol type epoxy resin.

Further, the present invention is preferably a surface-treated metal plate, wherein the epoxy resin is a phosphoric acid-modified epoxy resin.

Further, the present invention is preferably a surface-treated metal plate, wherein the epoxy resin is a modified epoxy resin having a primary hydroxyl group.

Further, the present invention is preferably a surface-treated metal plate, wherein the organic film is an organic film formed of a bisphenol type epoxy resin, a phosphoric acid modified epoxy resin, a glycoluril resin and a metal compound.

Further, the present invention is preferably a surface-treated metal plate, wherein the organic film is an organic film formed of a bisphenol type epoxy resin, a modified epoxy resin having a primary hydroxyl group, a glycoluril resin and a metal compound.

Further, the present invention is preferably a surface-treated metal plate, wherein the organic coating is an organic coating formed of a phosphoric acid-modified epoxy resin, a modified epoxy resin having a primary hydroxyl group, a glycoluril resin and a metal compound.

Further, the present invention is preferably a surface-treated metal plate, wherein the organic film is an organic film formed of a bisphenol type epoxy resin, a phosphoric acid modified epoxy resin, a modified epoxy resin having a primary hydroxyl group, a glycoluril resin and a metal compound. is there.

In a preferred aspect of the present invention, the metal compound contains at least one metal selected from the group consisting of Mg, Mn and Al, and the metal compound is phosphate.
It is a surface-treated metal plate which is at least one metal compound selected from the group consisting of carbonates, nitrates, acetates, hydroxides, fluorides, oxoacid salts and borate salts.

In a preferred aspect of the present invention, as the metal compound, Zn, Co, Ti, Sn, Ni, Fe,
Zr, Sr, Y, Cu, Ca, W, Mo, V, Ba, N
a, Nb, and K, containing at least one metal selected from the group consisting of a, Nb, and K, and containing phosphate, carbonate, nitrate, acetate, hydroxide, fluoride, oxoacid salt, borate salt, vanadic acid salt, and A surface-treated metal plate containing at least one metal compound selected from the group consisting of molybdates.

[0024] A further preferred aspect of the present invention is the surface-treated metal plate, wherein the organic coating further contains a water repellent.

The second aspect of the present invention is a surface treatment agent containing an epoxy resin, a glycoluril resin and a metal compound.

The preferred present invention is the surface treating agent, wherein the epoxy resin contains at least one selected from the group consisting of a bisphenol type epoxy resin, a phosphoric acid modified epoxy resin and a modified epoxy resin having a primary hydroxyl group.

In a preferred aspect of the present invention, the metal compound is at least one metal compound selected from the group consisting of Mg, Mn and Al, and the metal compound is phosphate, carbonate, nitrate, acetate or water. Oxides, fluorides,
The surface treatment agent is at least one metal compound selected from the group consisting of oxo acid salts and borate salts.

In a preferred aspect of the present invention, as the metal compound, Zn, Co, Ti, Sn, Ni, Fe,
Zr, Sr, Y, Cu, Ca, W, Mo, V, Ba, N
a, Nb, and K, containing at least one metal selected from the group consisting of a, Nb, and K, and containing phosphate, carbonate, nitrate, acetate, hydroxide, fluoride, oxoacid salt, borate salt, vanadic acid salt, and It is a surface treatment agent containing at least one metal compound selected from the group consisting of molybdates.

[0029] In a preferred aspect of the present invention, the surface treatment agent further contains a water repellent.

Further, the present invention is preferably the surface treatment agent as described above, which is for a metal plate.

[0031]

BEST MODE FOR CARRYING OUT THE INVENTION There is no particular limitation on the metal plate serving as the substrate of the surface-treated metal plate of the present invention, and examples thereof include electrogalvanized steel sheet, electrogalvanized-nickel plated steel sheet, hot-dip galvanized steel sheet, and zinc-aluminum. (Zn-5% Al) hot-dip galvanized steel sheet, zinc-aluminum (Zn-55% Al) hot-dip galvanized steel sheet, hot-rolled steel sheet, cold-rolled steel sheet, stainless steel sheet, copper-plated steel sheet, aluminum sheet, hot-dip Examples thereof include tin-zinc (Sn-10% Zn) plated steel sheet, hot-dip aluminized steel sheet, and turn (Pb-10% Sn) plated steel sheet. Zinc-based plated steel sheet is preferable, and electrogalvanized steel sheet is particularly preferable.

The organic film of the present invention is an organic film formed of an epoxy resin, a glycoluril resin and a metal compound. This organic film is a cured organic film formed of an epoxy resin, a glycoluril resin, and a metal compound, and firmly adheres to the metal plate that is the substrate. In the present invention, curing refers to complete curing, semi-curing or partial curing. The film thickness of the organic film is preferably 0.1 to 5 μm, more preferably 0.5 to 2.0 μm, and particularly preferably 0.7 to 1.5 μm. When the thickness exceeds 5 μm, although the corrosion resistance is improved, the organic film may be powdered during severe processing. On the other hand, when the thickness is less than 0.1 μm, the effect of improving the corrosion resistance tends to be small.

In the present invention, the glycoluril resin is a derivative in which methylol, butyrol, etc. are added to all or part of the 1-, 3-, 4-, 6-amino groups of glycoluril, methylation, methyl / ethyl. And alkylated derivatives such as butylated and the like, oligomers condensed through methylol and the like and alkyl derivatives thereof. Preferred are tetramethylolated glycoluril and its oligomers.

The organic film of the present invention has excellent wet adhesion and corrosion resistance as described above, but this is achieved by curing an epoxy resin with a glycoluril resin. That is, the flexible structure of the glycoluril resin imparts toughness to the hard and brittle structure of the formed cured film. In addition, the glycoluril structure of the cured film also increases the adhesion to the underlying metal plate. This allows
Corrosion resistance is improved because the inhibitory effect on the penetration of corrosion factors such as chlorine ions in the environment into the organic film is increased, and at the same time, the inhibitory effect on the penetration concentration of the corrosion factor due to the capillary phenomenon to the organic film / underlying interface is also increased. Furthermore, the presence of metal compounds increases the improvement in corrosion resistance.

The reason why the corrosion resistance is improved by the presence of the metal compound is not clear, but in the case of a galvanized steel sheet, it is estimated as follows. In general, the plating surface layer is oxidized and covered with an oxide with the passage of time, so that the wetting of the surface treatment agent and the adhesion of the organic film formed by baking the surface treatment agent become insufficient. By adding the metal compound to the surface treatment agent, the metal compound is strongly deposited and adhered on the plating surface layer, and the surface layer of the metal compound is covered with the organic coating before the metal compound deposited and adhered is oxidized. That is, it is presumed that the state is similar to a coating structure in which an inorganic layer that is not an oxide is further provided between the plating surface layer and the organic coating, and the wet adhesion is improved. Further, it is considered that the metal compound used in the present invention also has an effect of stabilizing or densifying a corrosion product of zinc in the plating layer, and it is presumed that this also enhances the corrosion resistance sustaining effect.

The epoxy resin used in the present invention is
It is preferably at least one selected from the group consisting of (a) bisphenol type epoxy resin, (b) phosphoric acid-modified epoxy resin, and (c) modified epoxy resin having a primary hydroxyl group.

(A) The bisphenol type epoxy resin is
A bisphenol type epoxy resin having an epoxy equivalent of 500 to 5000 is preferable, and 900 to 4000 is more preferable. When the epoxy equivalent is less than 500, the reaction rate with the glycoluril resin does not increase, a desired cured film cannot be obtained, and corrosion resistance may decrease. On the other hand, when the epoxy equivalent exceeds 5,000, the epoxy group becomes difficult to react, a desired cured film cannot be obtained, and corrosion resistance may deteriorate.

The (b) phosphoric acid-modified epoxy resin is preferably obtained by reacting a bisphenol type epoxy resin having an epoxy equivalent of 500 or less with a phosphoric acid compound. If the epoxy equivalent exceeds 500, the content of the P—OH group in the obtained (b) phosphoric acid-modified epoxy resin becomes small, so that a desired cured film may not be obtained.

The phosphoric acid compound is a phosphoric acid having two or more hydroxyl groups bonded to a phosphorus atom, and is a general term for acids obtained by hydrating diphosphorus pentoxide. In particular,
Examples thereof include metaphosphoric acid, pyrophosphoric acid, orthophosphoric acid, triphosphoric acid, and tetraphosphoric acid, with orthophosphoric acid being preferred. In addition, phosphoric acid monoesters such as monomethyl phosphoric acid, monooctyl phosphoric acid, and monophenyl phosphoric acid can also be used.

The (b) phosphoric acid-modified epoxy resin is
Its use is preferred because it is neutralized with an amine to produce a more stable aqueous resin composition. Examples of the amine include alkanolamines such as ammonia, dimethanolamine and triethanolamine, alkylamines such as diethylamine and triethylamine, and alkylalkanolamines such as dimethylethanolamine.

(B) The phosphoric acid-modified epoxy resin is P--O
H group equivalent is 150 to 1000, preferably 300 to 80
It is 0. When the P-OH group equivalent is less than 150, it becomes sticky when used as a surface treatment agent, which makes it difficult to use, and when it exceeds 1000, the adhesion with the metal plate may decrease. is there.

The modified epoxy resin having a primary hydroxyl group (c) is a bisphenol type epoxy resin having an epoxy equivalent of preferably 500 to 5000, more preferably 900 to 4000, and a primary amine, a secondary amine, or 2,2-dimethylol. Propionic acid, 2,2-dimethylolbutanoic acid,
Alternatively, it is preferably an epoxy polyol resin obtained by reacting with a carboxylic acid compound or the like. (C) The epoxy equivalent of the modified epoxy resin having a primary hydroxyl group is preferably 550 to 40,000, more preferably 600 to 2500.
It is 0. If the epoxy equivalent is less than 550, the reaction rate with the glycoluril resin does not increase, a desired cured film cannot be obtained, and corrosion resistance may decrease. Conversely, 4
If it exceeds 0000, the reaction of the epoxy group hardly occurs,
A desired cured film may not be obtained, and corrosion resistance may decrease.

The bisphenol type epoxy resin is a bisphenol F type epoxy resin, a bisphenol A type epoxy resin, or the like, and the secondary hydroxyl group thereof may be crosslinked with polyisocyanate or the like.

(C) Examples of the primary amine or secondary amine used in producing the modified epoxy resin having a primary hydroxyl group include monoethanolamine, methylethanolamine, butylethanolamine, diethanolamine, diisopropanolamine and dimethylamino. Alkanolamines such as propylethanolamine or dialkylamines such as dibutylamine, dioctylamine and the like can be mentioned. Above all, an epoxypolyol resin having a primary hydroxyl group obtained by using diethanolamine or the like is preferable because it can be cured even at a low temperature.

The equivalent ratio of the primary amine, secondary amine, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid or carboxylic acid compound to the bisphenol type epoxy resin is (c) the primary hydroxyl group produced. It is determined so that the epoxy equivalent of the modified epoxy resin having is preferably maintained at 600 to 25,000,
Usually, 0.1 to 0.9 equivalent to 1 equivalent of epoxy group,
It is preferably 0.2 to 0.8 equivalents.

The curing of the epoxy resin with the glycoluril resin is presumed to be due to the following mechanism. Epoxy group and hydroxyl group [(b) phosphorus each possessed by at least one epoxy resin selected from the group consisting of (a) bisphenol type epoxy resin, (b) phosphoric acid modified epoxy resin and (c) modified epoxy resin having primary hydroxyl group In the case of an acid-modified epoxy resin, the hydroxyl group bonded to the phosphorus atom] is added to each other to form a polymer, and the hydroxyl group present in the epoxy resin is
When baking the surface treatment agent at a temperature around 150 to 240 ° C., the hydroxyl group of the glycoluril resin (methylol group,
The epoxy resin is cured by dehydration (dealcoholization) condensation with an alkylmethylol group). It is presumed that the glycoluril structure and the hydroxyl group structure of the cured epoxy resin contribute to the strong wet adhesion to the base material of the metal plate and exhibit excellent corrosion resistance.

In the present invention, it is preferable to use (b) a phosphoric acid-modified epoxy resin. (B) The phosphoric acid-modified epoxy resin has a hydroxyl group bonded to a phosphorus atom, which reacts with the epoxy group to promote the polymerization of the epoxy resin, and the polymerized epoxy resin is cured by the glycoluril resin. This is because excellent corrosion resistance can be obtained. It is more preferable to use (b) phosphoric acid-modified epoxy resin and (a) bisphenol type epoxy resin, or (b) phosphoric acid-modified epoxy resin and (c) modified epoxy resin having a primary hydroxyl group.

When (c) the modified epoxy resin having a primary hydroxyl group is contained, (a) the bisphenol type epoxy resin and / or (b) the phosphoric acid modified epoxy resin is polymerized, and then the glycoluril resin is formed at a lower temperature. Dehydration (dealcoholization) condensation occurs. Therefore, when curing is performed by low temperature baking, it is advantageous to use the modified epoxy resin (c) having a primary hydroxyl group. Further, when the organic film of the present invention contains (c) an epoxy resin having a primary hydroxyl group, the denseness and air barrier properties of the organic film are improved, and the corrosion resistance is improved. It is more preferable to use the epoxy resin having.

The effect of the metal compound contained in the organic coating of the present invention on the corrosion resistance is not clear, but in the case of a galvanized steel sheet, it is presumed as follows. Zinc plating under the surface-treated film in a salt spray environment, especially from the damaged part of the film to the following anode reaction (1) and (2)
Zn ²⁺ and OH ⁻ are eluted by the cathode reaction of (3), and conductive ZnO is generated by the reaction of forming a corrosion product (3) and the dehydration reaction of (4) below. As a result, corrosion progresses. At this time, if a metal ion Me ^{n + is} present in the damaged portion (corroded portion) of the film, the reaction of (5) below causes Me
A stable corrosion product composed of Zn and Zn is formed and corrosion resistance is exhibited.

Zn → Zn ²⁺ + 2e ⁻¹ (1) H ₂ O + 1 / 2O ₂ + 2e ⁻ → 2OH ⁻ (2) Zn ²⁺ + 2OH ⁻ → Zn (OH) ₂ (3) Zn (OH ) ₂ → ZnO + H ₂ O (4) Me ^{n +} + Zn ²⁺ + xOH ⁻ → (Me, Zn) (OH) _x (5)

The metal compound constituting the organic film of the present invention is preferably at least one metal compound selected from the group consisting of Mg, Mn and Al, and further contains Zn, Co, Ti, Sn and Ni. , Fe, Z
r, Sr, Y, Cu, Ca, W, Mo, V, Ba, N
It is preferable to use together at least one metal compound selected from the group consisting of a, Nb and K. Particularly preferred is the case where a metal compound of Mg, Mn and Al is used in combination, and in addition to these, other metal compounds, especially Zn
This is the case when a compound is used in combination.

The metal compound of Mg, Mn and Al is at least one metal selected from the group consisting of phosphates, carbonates, nitrates, acetates, hydroxides, fluorides, oxoates and borates. It is preferably a compound. More preferred are phosphates, nitrates, acetates, oxoacids and borates. The other metal compound is
It is preferably at least one metal compound selected from the group consisting of phosphates, carbonates, nitrates, acetates, hydroxides, fluorides, oxoacids, borates, vanadates and molybdates. . More preferred are phosphates, nitrates, acetates, oxoacids and borates.

The metal compound is contained in a ratio of 2/98 to 40/60 in terms of mass with respect to the total solid content of the film. 2 /
If it is less than 98, the corrosion resistance may be poor, and if it exceeds 40/60, the corrosion resistance may be poor. 5/95 to 50/5 is preferred
0, particularly preferably 10/90 to 20/80.
When the metal compound is used in combination, the mass ratio of each compound is not particularly limited. For example, when the metal compound of Mg, Mn and Al is used in combination, Mg / Mn / Al = 1/1/1 to 5 /
It is 5/1.

The organic coating of the present invention may further contain a metal compound and is thus excellent in corrosion resistance. However, in order to further improve the corrosion resistance, a urethane resin capable of forming a tough coating is added. It is effective. That is, the inclusion of the urethane resin enhances the ability to suppress the penetration of the corrosion factor into the organic film and improves the corrosion resistance. Moreover, the adhesion of the organic film is improved. As the urethane resin, a self-emulsifying anionic urethane resin having an ether skeleton or an ether / ester skeleton is preferable. The urethane resin is preferably contained in an amount of 5 to 20% by mass based on the solid content of the surface treatment agent.

The organic film of the present invention preferably further contains a water repellent. Since the water repellent is hydrophobic, it tends to be concentrated on the surface layer of the organic film. Therefore, the invasion of the corrosion factor into the organic film is suppressed by the surface layer, and the corrosion resistance is improved. In addition, it improves wet adhesion. The water repellent is a fluororesin, polyethylene wax, a resin coated with polyethylene wax, or the like. The water repellent is preferably contained in an amount of 5 to 20% by mass based on the solid content of the surface treatment agent. The organic film of the present invention may further contain various additives which can be added to the organic film to impart and improve various properties. For example, a silane coupling agent or the like can be included.

The resin composition ratio of the organic film of the present invention is, in terms of mass, epoxy resin / glycoluril resin = 50/50.
˜95 / 5, preferably = 60/40 to 90/10. When the composition ratio is less than 50/50, the residual rate of the glycoluril resin becomes high and the corrosion resistance deteriorates. On the other hand, if the composition ratio exceeds 95/5, the glycoluril resin is deficient, a sufficient cured film cannot be obtained, and the corrosion resistance deteriorates.

When (a) bisphenol type epoxy resin and (b) phosphoric acid modified epoxy resin are used in combination,
(B) / (a) = 10/90 to 50/50, preferably 15/85 to 40/60. The composition ratio is 10/90
If it is less than 50%, the adhesion to the underlying metal plate may not be obtained, and if it exceeds 50/50, the performance such as corrosion resistance may be deteriorated.

When (a) bisphenol type epoxy resin and (c) modified epoxy resin having a primary hydroxyl group are used in combination, (a) / (c) = 5/95 to 30/70, preferably 10/90 to 20 /. 80. The composition ratio is 5/9
If it is less than 5, the amount of the curing and dehydration (dealcoholization) reaction of the epoxy resin with glycoluril resin becomes excessive,
Corrosion resistance may deteriorate. If it is more than 30/70, on the contrary, the curing of the epoxy resin with the glycoluril resin is insufficient, and the corrosion resistance may deteriorate.

When the phosphoric acid-modified epoxy resin (b) and the modified epoxy resin (c) having a primary hydroxyl group are used in combination,
(B) / (c) = 5 / 95-40 / 60, preferably 7
/ 93 to 20/80. When the composition ratio is less than 5/95, the polymerization of the epoxy resin is insufficient, the glycoluril resin involved in dehydration (dealcoholization) condensation is insufficient, and the corrosion resistance may deteriorate. If it is more than 40/60, similarly, the polymerization is insufficient, and the glycoluril resin involved in dehydration (dealcoholization) condensation is insufficient,
Corrosion resistance may deteriorate.

(A) Bisphenol type epoxy resin,
When using (b) a phosphoric acid-modified epoxy resin and (c) a modified epoxy resin having a primary hydroxyl group, (a) / (b) /
(C) = 10/10/80 to 10/40/50, preferably 10/20/70 to 10/30/60. If the composition ratio is deviated from the above, the polymerization of the epoxy resin is insufficient, the glycoluril resin involved in the dehydration condensation may be insufficient, and the corrosion resistance may be deteriorated.

The organic film of the present invention is formed by preparing a surface treatment agent containing various components contained in the organic film, applying it to a metal plate, and curing it. The surface treatment agent is an aqueous solution or an aqueous dispersion prepared by adding an epoxy resin, a glycoluril resin, a metal compound and a water repellent, and if necessary, a urethane resin or the like to an aqueous solvent and stirring and mixing them. . If necessary, it may be prepared by heating and making it aqueous using a nonionic emulsifier.
The concentration of the surface treatment agent may be in the solid content range where the stability of the organic resin is ensured, and the solid content concentration is about 5 to 35 mass%.

In the organic film of the present invention, a surface treatment agent is brought into contact with the surface of a metal plate by means such as roll coating, spray coating, brush coating, dip coating and curtain flow, and is pressed with a Ringer roll and dried, By baking, the aqueous solvent is volatilized, and the epoxy resin is formed by the progress of curing. The surface of the metal plate may be pretreated in advance or may be subjected to chemical conversion treatment such as phosphate treatment before the formation of the organic film. The coating amount / adhesion amount is adjusted so as to fall within the range of the film thickness of the organic film described above, but the film thickness of the entire film when a chemical conversion treatment layer or the like is provided is preferably 0.1 to 5 μm.

The baking is performed in the range of 200 to 2 when only (a) bisphenol type epoxy resin and / or (b) phosphoric acid modified epoxy resin is used as the epoxy resin.
It is carried out at a relatively high temperature of about 40 ° C. On the other hand, when (c) a modified epoxy resin having a primary hydroxyl group is used, or when it is used in combination with another epoxy resin, 150
It is carried out at a relatively low temperature of about 200 ° C. If the baking temperature is lower than the lower limit value, the curing may be slightly insufficient or the solvent may remain in the organic film, so that the corrosion resistance may be slightly deteriorated. When the baking temperature is higher than the upper limit, there is no particular problem, but yellowing due to partial decomposition of components in the organic film may be observed.

[0064]

EXAMPLES The present invention will be described in detail below based on examples. [Invention Examples 1 to 90, Comparative Examples 1 to 4] The following epoxy resins (a) to (c), glycoluril resins A to D, benzoguanamine resins E to F and melamine resins G to H (the above two resins are referred to as amino resins). , Urethane resins A to G, metal compounds, and water repellents A to D at a ratio (a ratio to 100 parts by mass of total solid content) described in Table 1 are added to water, and mixed by stirring at room temperature. A treating agent was prepared. The obtained surface treatment agent was roll-coated on the following metal plates A to N.
It heated so that the metal plate temperature might become 160 degreeC, 180 degreeC, and 220 degreeC in 20 seconds, the organic film with a film thickness of 0.3-5 micrometers was formed, and the test piece was produced. The characteristics of the organic film of the test piece are shown in Table 1.

Metal plates A to N; Plate A; Electrogalvanized steel plate (plate thickness: 1.0 mm, Z
n: 20 g / m ² ) Plate B; Electric zinc-nickel plated steel plate (plate thickness: 1.0
mm, Zn + Ni: 20 g / m ² , Ni: 12% by mass) Plate C; Hot dip galvanized steel plate (plate thickness: 1.0 mm, Z
n: 60 g / m ² ) Plate D; Galvannealed steel sheet (plate thickness: 1.0 m
m, Zn: 60 g / m ² , Fe: 10% by mass) Plate E: 5% zinc aluminized steel plate (plate thickness: 1.
0 mm, 60 g / m ² , Al: 5 mass%) Plate F; Zinc 55% aluminum plated steel plate (plate thickness:
1.0 mm, 60 g / m ² , Al: 55 mass%)

Plate G: Hot-rolled steel plate (plate thickness: 1.2 mm) Plate H; Cold-rolled steel plate (plate thickness: 1.0 mm) Plate I: Stainless steel plate SUS430 (plate thickness: 1.0)
mm) Plate J; Copper-plated steel plate (plate thickness: 1.0 mm, Cu: 30)
g / m ² ) Plate K; Aluminum plate JIS 5052 (Al-M
g alloy type) (plate thickness: 1.0 mm) Plate L; hot-dip galvanized steel plate (plate thickness: 1.0 m
m, Sn: 60 g / m ² , Zn: 10% by mass) Plate M; Hot-dip galvanized steel plate (plate thickness: 1.0 mm, A
l: 50 g / m ² ) Plate N; Turn-plated steel plate (plate thickness: 1.0 mm, Pb:
40 g / m ² , Sn: 10 mass%)

Epoxy Resins (a) to (c) (a) Bisphenol type epoxy resin was produced by the following method. To 680 g of bisphenol A type epoxy resin (a) having an epoxy equivalent of 1950, 132 g of propylene glycol monomethyl ether was added, and then 84 g of a nonionic emulsifier (“Adecapluronic F68”) was added to make a uniform solution, and then 649 g of water was gradually added. Add
An epoxy resin emulsion having an epoxy equivalent of 4000 and a solid content concentration of 50% by mass was obtained using a triaxial mixer.

(B) The phosphoric acid-modified epoxy resin was produced by the following method. (B1) Amine-neutralized product of phosphoric acid-modified epoxy resin (anion type) 85 g of orthophosphoric acid and 140 g of propylene glycol monomethyl ether were charged, 425 g of bisphenol A type epoxy resin having an epoxy equivalent of 250 was gradually added, and the mixture was heated at 80 ° C for 2 hours. It was made to react. After the completion of the reaction, at 50 ° C. or lower, 150 g of an aqueous 29% by mass ammonia solution was gradually added, and further 1150 g of water was added to the amine neutralized product of a phosphoric acid-modified epoxy resin having an acid value of 35 and a solid content concentration of 25% by mass. Got

(B2) Nonionic emulsion of phosphoric acid-modified epoxy resin 95 g of orthophosphoric acid and 198 g of propylene glycol monomethyl ether were charged, 396 g of bisphenol A type epoxy resin having an epoxy equivalent of 250 was gradually added, and the mixture was reacted at 80 ° C. for 2 hours. It was After completion of the reaction, at 80 ° C. or lower, a nonionic emulsifier (“Adeka Pluronic F6
8 ″) 25 g was gradually added, and after becoming uniform, 264 g of water was further added to obtain an acid value of 65 and a solid content concentration of 50 mass%.
To obtain a phosphoric acid-modified epoxy resin.

(B3) Amine-neutralized product of phosphoric acid-modified epoxy resin (anion type) 85 g of orthophosphoric acid and 140 g of propylene glycol monomethyl ether were charged, and 807 g of bisphenol A type epoxy resin having an epoxy equivalent of 475 was gradually added, and the mixture was heated to 80 ° C. And reacted for 2 hours. After the completion of the reaction, at 50 ° C. or lower, 150 g of 29 mass% aqueous ammonia solution was gradually added, and further 2386 g of water was added to the amine neutralized product of a phosphoric acid-modified epoxy resin having an acid value of 21 and a solid content concentration of 25 mass%. (Anion type) was obtained.

The modified epoxy resin (c) having a primary hydroxyl group was produced by the following method. (C1) Epoxy equivalent 1
1950 g of 950 bisphenol type epoxy resin was dissolved in 876 g of propylene glycol monomethyl ether, and then 78.8 g of diethanolamine was added,
The reaction was carried out at 100 ° C. for 3 hours to obtain a modified epoxy resin emulsion having an epoxy equivalent of 11600. Then, 256 g of a nonionic emulsifier (“ADEKA Pluronic F68”) was added and homogenized, and then 2553 g of water was gradually added, and an epoxy equivalent of 22500, using a triaxial mixer,
A modified epoxy resin emulsion having a primary hydroxyl group with a solid content of 40% by weight was obtained.

(C2) 1950 g of a bisphenol type epoxy resin having an epoxy equivalent of 1950 was dissolved in 876 g of propylene glycol monomethyl ether, and then 2,2
After adding 100 g of dimethylolpropionic acid and homogenizing it, 1 g of dimethylbenzylamine as a catalyst was added and reacted at 130 ° C. for 3 hours to give an epoxy equivalent of 12
It was confirmed to be 000. Next, 513 g of a nonionic emulsifier (“ADEKA Pluronic F68”) was added and homogenized, and then 2296 g of water was gradually added to obtain a modified epoxy resin emulsion having an epoxy equivalent of 22300 and a solid concentration of 40% by mass having a primary hydroxyl group. Got

(C3) 950 g of a bisphenol type epoxy resin having an epoxy equivalent of 950 is dissolved in 380 g of propylene glycol monomethyl ether, 79 g of diethanolamine is added, and the mixture is reacted at 100 ° C. for 3 hours,
An epoxy polyol resin emulsion having an epoxy equivalent of 5640 was obtained. Next, 127 g of a nonionic emulsifier (“ADEKA Pluronic F68”) was added to make the mixture uniform, and 1354 g of water was gradually added to the mixture. Using a triaxial mixer, the epoxy equivalent was 11500 and the solid content concentration was 40% by mass.
A modified epoxy resin having primary hydroxyl groups was obtained.

Glycoluril resin; Resin A: "Cymel 1170" (completely butylated glycoluril resin, manufactured by Mitsui Cytec Co., Ltd.) Resin B: "Cymel 1171" (methyl / ethyl mixed alkylated glycoluril resin, Mitsui Cytec ( Resin C: "Cymel 1172" (tetramethylol glycoluril resin, manufactured by Mitsui Cytec Co., Ltd.) Resin D: "Cymel 1174" (completely methylated glycoluril resin, manufactured by Mitsui Cytec Co., Ltd.)

Amino resin Resin E: "Cymel 1123" (methyl / ethyl mixed alkylated benzoguanamine resin, manufactured by Mitsui Cytec Co., Ltd.) Resin F: "Cymel 106" (completely methylated benzoguanamine resin, manufactured by Mitsui Cytec Co., Ltd.) Resin G: "Cymel 303" (completely methylated melamine resin, manufactured by Mitsui Cytec Co., Ltd.) Resin H: "Cymel 370" (partially methylated melamine resin, manufactured by Mitsui Cytec Co., Ltd.)

Urethane resin: Urethane A: "Superflex 126" (ester / ether type, anionic, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) Urethane B: "Superflex 110" (ether type, anionic, Daiichi Kogyo) Pharmaceutical Co., Ltd. Urethane C: “Superflex 130” (ether type, anionic, manufactured by Dai-ichi Kogyo Co., Ltd.) Urethane D: “Superflex 150” (ester / ether type, anionic, Daiichi Kogyo) Pharmaceutical Co., Ltd.)

Urethane E: "Superflex 42
0 "(carbonate type, anionic, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) Urethane F:" Superflex 700 "(aromatic isocyanate type, anionic, Daiichi Kogyo Seiyaku Co., Ltd.)
Urethane G: "Superflex E4000" (ether type, nonionic, manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)

Metal compound: Metal compound Mg-P: magnesium phosphate Metal compound Mg-H: Magnesium hydroxide Metal compound Mg-N: magnesium nitrate Metal compound Mg-B: Magnesium borate Metal compound Mn-C: Manganese carbonate Metal compound Mn-P: manganese phosphate Metal compound Al-H: Aluminum hydroxide Metal compound Al-A: Aluminum acetate Metal compound Al-F: Aluminum fluoride

[0079] Metal compound Zn-N: Zinc nitrate Metal compound Zn-C: Zinc carbonate Metal compound Co-N: Cobalt nitrate Metal compound Ti-N: Titanium nitrate Metal compound Sn-N: tin nitrate Metal compound Ni-N: Nickel nitrate Metal compound Ni-H: Nickel hydroxide Metal compound Fe-N: iron nitrate Metal compound Zr-H: Zirconium hydroxide

[0080] Metal compound Sr-N: Strontium nitrate Metal compound Sr-C: Strontium carbonate Metal compound YN: Yttrium nitrate Metal compound Cu-N: Copper nitrate Metal compound Ca-N: calcium nitrate Metal compound VN: vanadium nitrate Metal compound Ba-N: barium nitrate Metal compound Na-V: sodium vanadate Metal compound Na-Mo: Sodium molybdate Metal compound KB: potassium borate

Water Repellent; Water Repellent A: "Aflon-XAD911" (Fluorine Resin Emulsion, Asahi Glass Fluoropolymers Co., Ltd.) Water Repellent B: "Aflon-QAD938" (Fluorine Resin Emulsion, Asahi Glass Fluoropolymers Co., Ltd.) ) Water repellent C: "Hydrocer 6099" (polyethylene shell-coated fluororesin emulsion, manufactured by Shamrock Co., Ltd.) Water repellent D: "HYTEC 9017" (polyethylene wax emulsion, manufactured by Toho Kagaku Co., Ltd.)

The following characteristics of each test piece (corrosion resistance of flat plate portion and adhesion of cross cut portion in SST environment, CCT
The corrosion resistance of the processed part in the environment, the conductivity after the corrosion resistance test, the adhesion of the top coating, and the fingerprint resistance) were evaluated according to the following test methods. (Corrosion resistance of flat plate part in SST environment) 70mm x 1
After shearing to a size of 50 mm, the end face portion was sealed, a salt spray test (JIS Z2371) was performed, and the time required until rust was generated in 5% of the surface area of each test piece was evaluated according to the following evaluation criteria. . The results are shown in Table 2. ◎; 120 hours or more ○; 96 hours or more and less than 120 hours △; 72 hours or more and less than 96 hours ×; Less than 72 hours

(Adhesion of cross-cut portion in SST environment;
Wet adhesion) Processed material: After shearing the test piece into a size of 50 mm × 150 mm, an Erichsen 9 mm overhang is performed so that the concave portion becomes the surface. The average cut width (one side) from the scratch of the organic film when a cross-cut scratch reaching the base metal is applied to the flat surface of the processed material with a cutter knife is evaluated. The results are shown in Table 2. ◎; 0 mm ○; more than 0 mm and less than 1 mm △; more than 1 mm and less than 2 mm ×; more than 2 mm

(Corrosion resistance of machined part in CCT environment) As a CCT condition, 8 cycles of SST-16 hours of rest are set as one cycle, and evaluation is made by the number of cycles until rust is generated in each part of the above-mentioned machined material. The results are shown in Table 2. ◎; 4 cycles or more ○; 3 cycles △; 2 cycles ×; 1 cycle or less

(Conductivity after Corrosion Resistance Test) CCT Test 2
The surface electric resistance at the flat surface portion after the cycle was measured with an ESP probe using a surface electric resistance meter ("Loresta GP" manufactured by Mitsubishi Chemical Co., Ltd.), and then evaluated according to the following criteria.
The results are shown in Table 2. ○; 1 mΩ or less △; more than 1 mΩ 10 mΩ or less ×; more than 10 mΩ

(Adhesion of Topcoat Coating) JIS K 540
0, melamine / alkyd resin ("Olga Select 120 White", Nippon Paint Co., Ltd.)
Bar coating to a film thickness of 20 μm, and
After baking at 5 ° C for 15 minutes, cuts that penetrate the organic film on each test piece and reach the metal plate base are made in a grid pattern with a cutter knife at 1 mm intervals, and "Cellotape (registered trademark)" is placed on the grid pattern. The adhered state of the coating film after "" was attached and peeled off was visually observed and evaluated according to the following evaluation criteria. The results are shown in Table 2. ◎: Film residual rate 100% ○: Film residual rate 95% or more and less than 100% △; Film residual rate 85% or more and less than 95% ×; Film residual rate 65% or more and less than 85% XX; Film residual rate less than 65%

(Fingerprint resistance) The change in color tone (L value, a value, b value) before and after applying white petrolatum to each test piece was measured by a spectroscopic color difference meter ("SQ2000", manufactured by Nippon Denshoku Co., Ltd.). Was evaluated using ΔE represented by the following formula (1) according to the following evaluation criteria. The results are shown in Table 2. ◎: ΔE1 or less ○: ΔE1 over 2 or less △; ΔE2 over 3 or less ×: ΔE3 over

[0088]

[Equation 1]

[0089]

[Table 1]

[0090]

[Table 2]

[0091]

[Table 3]

[0092]

[Table 4]

[0093]

[Table 5]

[0094]

[Table 6]

[0095]

[Table 7]

[0096]

[Table 8]

[0097]

[Table 9]

[0098]

[Table 10]

[0099]

[Table 11]

[0100]

[Table 12]

[0101]

The surface-treated metal plate of the present invention is a so-called chromate-free metal plate containing no chromium,
In particular, since it has excellent corrosion resistance and wet adhesion, it can be used as a substitute for conventional chromate-treated steel sheets used in the fields of automobiles, home appliances, and building materials. Furthermore, since it does not contain chromium, it can be used for a wide range of applications from container-related items, tableware-related items, to interior building materials. Further, the surface treating agent of the present invention is extremely effective for producing the above chromate-free treated metal plate.

Continued front page    F-term (reference) 4F100 AA04B AA05B AA08B AA17B                       AB01A AB02B AB09B AB10B                       AB12B AB14B AB15B AB16B                       AB17B AB18B AB19B AB20B                       AB21B AK04 AK17 AK35                       AK51 AK53B AL05B AL07B                       BA02 CA30B GB07 GB32                       GB48 JB02 JB06B JL11                 4J038 DB061 DB121 DB161 DB401                       DJ002 GA03 GA14 HA186                       HA256 HA266 HA326 HA406                       NA03 NA04 NA12 PC02                 4K044 AA01 AB02 BA10 BA11 BA12                       BA17 BA18 BA21 BB03 BC02                       BC05 CA11 CA53 CA62

Claims (17)

[Claims] 1. A surface-treated metal plate having an organic film formed of an epoxy resin, a glycoluril resin, and a metal compound on at least one surface of the metal plate. 2. The surface-treated metal plate according to claim 1, wherein the epoxy resin is a bisphenol type epoxy resin. 3. The surface-treated metal plate according to claim 1, wherein the epoxy resin is a phosphoric acid-modified epoxy resin. 4. The surface-treated metal plate according to claim 1, wherein the epoxy resin is a modified epoxy resin having a primary hydroxyl group. 5. The surface-treated metal plate according to claim 1, wherein the organic film is an organic film formed of a bisphenol type epoxy resin, a phosphoric acid-modified epoxy resin, a glycoluril resin and a metal compound. 6. The surface-treated metal plate according to claim 1, wherein the organic film is an organic film formed of a bisphenol type epoxy resin, a modified epoxy resin having a primary hydroxyl group, a glycoluril resin and a metal compound. 7. The organic film is a phosphoric acid-modified epoxy resin,
The surface-treated metal plate according to claim 1, which is an organic film formed of a modified epoxy resin having a primary hydroxyl group, a glycoluril resin, and a metal compound. 8. The surface-treated metal according to claim 1, wherein the organic film is an organic film formed from a bisphenol type epoxy resin, a phosphoric acid modified epoxy resin, a modified epoxy resin having a primary hydroxyl group, a glycoluril resin and a metal compound. Board. 9. The metal compound contains at least one metal selected from the group consisting of Mg, Mn and Al, and the metal compound is a phosphate, carbonate, nitrate, acetate, hydroxide or fluoride. 9. The surface-treated metal plate according to claim 1, which is at least one metal compound selected from the group consisting of oxo acid salts and borate salts. 10. The metal compound further comprises Zn,
Co, Ti, Sn, Ni, Fe, Zr, Sr, Y, C
u, Ca, W, Mo, V, Ba, Na, Nb and K, containing at least one metal selected from the group consisting of phosphate, carbonate, nitrate, acetate, hydroxide, fluoride, The surface-treated metal plate according to claim 9, comprising at least one metal compound selected from the group consisting of oxo acid salts, borate salts, vanadate salts, and molybdate salts. 11. The surface-treated metal plate according to claim 1, wherein the organic film further contains a water repellent agent. 12. A surface treating agent comprising an epoxy resin, a glycoluril resin and a metal compound. 13. The surface treatment agent according to claim 12, wherein the epoxy resin contains at least one selected from the group consisting of a bisphenol type epoxy resin, a phosphoric acid-modified epoxy resin and a modified epoxy resin having a primary hydroxyl group. 14. The metal compound is Mg, Mn and Al.
Is at least one metal compound selected from the group consisting of, and the metal compound is selected from the group consisting of phosphates, carbonates, nitrates, acetates, hydroxides, fluorides, oxoacid salts and borate salts. The surface treatment agent according to claim 12 or 13, which is at least one metal compound. 15. The metal compound further comprises Zn,
Co, Ti, Sn, Ni, Fe, Zr, Sr, Y, C
u, Ca, W, Mo, V, Ba, Na, Nb and K, containing at least one metal selected from the group consisting of phosphate, carbonate, nitrate, acetate, hydroxide, fluoride, The surface treatment agent according to claim 14, which contains at least one metal compound selected from the group consisting of oxo acid salts, boric acid salts, vanadate salts, and molybdate salts. 16. The surface treatment agent according to claim 12, wherein the surface treatment agent further contains a water repellent agent. 17. The surface treating agent according to claim 12, which is for a metal plate.