JP2003226986A - Surface-treated metal sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-treated metal sheet such as a galvanized steel sheet in which a specific waste water treatment is needless in the coating process of a surface treatment agent or in the use of the surface treated galvanized steel sheet and which has an organic coating film having excellent corrosion resistance, conductivity and a wet adhesion property. <P>SOLUTION: The surface-treated metal sheet has an intermediate layer containing a metal (except Cr) at least on one surface of a metal sheet and the organic coating film formed from an epoxy resin and a glycoluril resin on the intermediate layer. <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, conductivity and wet adhesion, and particularly to a surface-treated zinc-based plated steel sheet.

[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, which comprises (c) a free acid for pH adjustment, and (d) a chromium-free composition containing 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 treating 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) a divalent or higher valent metal ion such as Mn or Co; (b) an acid such as fluoroacid or phosphoric acid; (c) a silane coupling agent; and (d) a polymer unit of 2 to 50.
A water-soluble surface treatment agent obtained by dissolving the water-soluble polymer of 1. in a water-based medium (for example, Patent Document 4).

(A) thiocarbonyl group-containing compound,
A method of coating 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,
When the film thickness is reduced, a portion 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. If captured microscopically, 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] Japanese Patent Laid-Open No. 11-50010

[Patent Document 4] Japanese Patent Laid-Open No. 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. No special drainage treatment is required, and the drawbacks of conventional surface-treated zinc-based plated steel sheets are improved. In particular, zinc-based plated steel sheets with organic coatings with excellent corrosion resistance, conductivity and wet adhesion It is intended to provide various metal plates having a coating.

[0014]

SUMMARY OF THE INVENTION Therefore, the present invention provides
A surface treatment characterized by having an intermediate layer containing a metal (excluding chromium) on at least one surface of a metal plate, and having an organic film formed of an epoxy resin and a glycoluril resin on the intermediate layer. It is a metal plate.

In a preferred aspect of the present invention, the metal is Cu or C.
o, Fe, Mn, Sn, V, Mo, Mg, Ba, Al,
W, Ca, Sr, Zr, Nb, Y, Ti, Ni, Na,
The surface-treated metal plate is at least one metal selected from the group consisting of K and Zn.

The preferred present invention is the surface-treated metal plate, wherein the epoxy resin is at least one epoxy resin 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 is Mn,
The surface-treated metal plate is at least one selected from the group consisting of Mg, V, and Al.

In a preferred aspect of the present invention, the metal is Mn,
It is a surface-treated metal plate which is at least one selected from the group consisting of Mg, V, Al and Zn.

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

[0020]

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.

For the intermediate layer of the present invention, a metal plate is coated with a surface treating agent containing a metal compound or a resin, or an aqueous solution containing a metal compound is coated, and then a surface treating agent containing a resin is coated. It is a thin film which is present in the lower layer of the organic film formed by and is firmly adhered to the metal plate and has corrosion resistance. The intermediate layer contains metal as a main component and may contain an epoxy resin and a glycoluril resin as a resin.

The presence of the intermediate layer is obtained by applying a surface treatment agent containing a metal compound onto a zinc-based plated steel sheet and subjecting the sample having a film formed on the surface thereof to GDS (Glow Discharge Spectroscopy).
Was measured and confirmed by. RF-GDS manufactured by Rigaku Co., Ltd.
3860 (Anode diameter 4mmφ, power 20W, Ar gas flow rate 3
00 cc / min) was used. The measurement results are shown in FIG. 1 with the horizontal axis representing the sputtering time and the vertical axis representing the emission intensity (V). In FIG. 1, when the sputtering time is 0 second,
It indicates the outermost surface of the coating of the measurement sample, and the inside of the coating is displayed as the time elapses. From the distribution of various elements, C and N
The presence of three layers: a layer containing a large amount of metal and a small metal content, a layer containing a large amount of metal Zn and Mn in addition to P, and a layer containing a large amount of Zn and a small amount of C. Is recognized.
The three layers were named an organic film, an intermediate layer and a plating layer, respectively, from the side closer to the outermost surface of the zinc-based plated steel sheet.
From FIG. 1, the film thickness of the intermediate layer can be determined based on the iron-equivalent sputtering rate.

The thickness of the intermediate layer is 50 to 500 nm, preferably 100 to 200, though it varies depending on the coating conditions of the surface treating agent and the kind of metal contained in the surface treating agent.
nm. If it is less than 50 nm, the metal plate is not sufficiently covered, and the corrosion resistance deteriorates. If the thickness exceeds 500 nm, the intermediate layer becomes brittle, so cracking of the intermediate layer or peeling between the intermediate layer and the organic coating occurs due to bending, etc., the adhesion between the organic coating and the zinc plating layer deteriorates, and corrosion resistance deteriorates. To do.

In preference to the epoxy resin and glycoluril resin which are organic film components contained in the surface treatment agent, the dissociated metal ions forming the intermediate layer ionically bond with the metal ions of the metal plate to form a strong adhesion state. It is presumed that it contributes to the improvement of corrosion resistance. In the present invention, since the organic film can be made thinner due to the presence of the intermediate layer,
Not only can corrosion resistance be improved, but conductivity can also be increased.

The metal constituting the intermediate layer of the present invention is a metal derived from the above-mentioned metal compound, and Mg and M are preferable.
n, V or Al metals and mixtures thereof,
Further, it is a case where a metal other than Mg, Mn, V or Al is used in combination. Specifically, Cu, Co, Fe,
Mn, Sn, V, Mo, Mg, Ba, Al, W, Ca,
Sr, Zr, Nb, Y, Ti, Ni, Na, K and Z
It is at least one metal selected from the group consisting of n. Particularly preferred are Mg, Mn, V, Al metals and Z.
This is the case where n metals are used together.

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. Two
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 / 95-50 / is preferred
A ratio of 50, particularly preferably 10/90 to 20/80. When the metal compound is used in combination, the composition 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 /
It is 1 to 5/5/1.

The organic film of the present invention is an outermost surface layer formed on the intermediate layer and is formed of an epoxy resin and a glycoluril resin. That is, the organic film is a cured organic film formed of an epoxy resin and a glycoluril resin, and firmly adheres to the intermediate layer, and in some cases, to a metal plate which is a part of the substrate. In the present invention, curing refers to complete curing, semi-curing or partial curing.

The thickness of the organic coating is preferably 0.5 to 4.0 μm, more preferably 1.0 to 3.0 μm. When the thickness exceeds 4.0 μm, although the corrosion resistance is improved, the organic film may powder when subjected to severe processing. On the other hand, when the thickness is less than 0.5 μm, the effect of improving the corrosion resistance tends to be small.

The organic film of the present invention is excellent in wet adhesion and corrosion resistance as described above, but this is achieved by curing the epoxy resin with the 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 enhances the adhesion to the intermediate layer and, in some cases, the metal plate. As a result, the corrosion resistance is improved because the ability to suppress the penetration of corrosion factors such as chlorine ions in the environment into the organic coating is increased and the strength to inhibit the concentration of the corrosion factor due to the capillary phenomenon at the coating / metal plate interface is also increased. To be done.

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 epoxy resin of the present invention may be 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. preferable.

(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 phosphoric acid-modified epoxy resin (b) 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 generic 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) has an epoxy equivalent of preferably 500 to 5000,
More preferably, an epoxy obtained by reacting 900 to 4000 bisphenol type epoxy resin with a primary amine, a secondary amine, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, a carboxylic acid compound or the like. It is preferably a polyol resin. (C) The epoxy equivalent of the modified epoxy resin having a primary hydroxyl group is preferably 550 to 40,000, more preferably 600 to 2
It is 5000. When the epoxy equivalent is less than 550,
There is a possibility that the reaction rate with the glycoluril resin does not increase, the desired cured film cannot be obtained, and the corrosion resistance decreases. On the other hand, when it exceeds 40,000, the reaction of the epoxy group is difficult to occur, a desired cured film cannot be obtained, and the 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 may further have a secondary hydroxyl group thereof crosslinked with polyisocyanate or the like.

(C) The primary amine or secondary amine used in producing the modified epoxy resin having a primary hydroxyl group includes 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 respectively contained in 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 [(b)
In the case of a phosphoric acid-modified epoxy resin, a hydroxyl group formed when the phosphorus atom-bonded hydroxyl group] is added to each other to be polymerized, and a hydroxyl group that is present in the epoxy resin have a surface treatment agent of 150 to When baked at a temperature around 240 ° C., the epoxy resin is cured by dehydration (dealcoholization) condensation with the hydroxyl groups (methylol group, alkylmethylol group, etc.) of the glycoluril resin. 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) a modified epoxy resin having a primary hydroxyl group is contained, (a) a bisphenol type epoxy resin and / or (b) a phosphoric acid modified epoxy resin is polymerized, and then a 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 cathodic reaction of (3), and conductive ZnO is generated by the formation reaction of the corrosion product (Zn (OH) ₂ ) of (3) below and the dehydration reaction of (4) below. As a result, corrosion progresses. At this time, if the metal ion Me ^{n +} is present in the damaged portion (corroded portion) of the film, a stable corrosion product composed of Me and Zn is formed by the reaction of the following (5), 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 organic film of the present invention is formed on the metal-containing intermediate layer and has excellent corrosion resistance. However, in order to further improve the corrosion resistance, a urethane resin capable of forming a tough film is used. It is effective to include it. 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 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 curing and dehydration (dealcoholization) reaction of the epoxy resin with the glycoluril resin becomes excessive, and the 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 prepared by preparing a surface treatment agent containing an epoxy resin, a glycoluril resin, or further containing a metal compound or a water repellent, and applying the surface treatment agent to a metal plate and curing it. It is formed. The surface treatment agent is an aqueous solution or an aqueous dispersion prepared by further adding a urethane resin or the like to an aqueous solvent and mixing with stirring, if necessary. If necessary, it may be prepared by heating and making it aqueous using a nonionic emulsifier.

The concentration of the surface treatment agent containing the resin may be in the solid content range where the stability of the resin is ensured, and the solid content concentration is about 5 to 35% by mass. The metal compound is preferably 5 to 60 mass% of the solid content. When two or more kinds of metal compounds are used in combination, it is preferable that the amount of each compound is 1 to 50% by mass. If it is less than 5% by mass, the corrosion resistance tends to be poor, and if it exceeds 60% by mass, the weldability tends to be poor. The concentration of the surface treatment agent may be in the range where the metal compound is dissolved or in the solid content range where the stability of the resin is secured.

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, pressed by 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.

For baking, if only (a) a bisphenol type epoxy resin and / or (b) a phosphoric acid-modified epoxy resin are used as the epoxy resin, 200 to 2 is used.
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 and when it is used in combination with another epoxy resin, it is 150 to 200.
It is carried out at a relatively low temperature of about ℃. When 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.

[0057]

EXAMPLES The present invention will be described in detail below based on examples. [Invention Examples 1 to 75, Comparative Examples 1 to 6] 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.
Heat the metal plate to 180 ° C in 20 seconds,
A test piece was prepared by forming an organic film having a film thickness of 0.3 to 5 μm. 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, Zn:
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, Zn:
60 g / m ² ) Plate D; Hot-dip galvanized steel sheet (plate thickness: 1.0 mm,
Zn: 60 g / m ² , Fe: 10% by mass) Plate E; Zinc 5% aluminum-plated steel plate (plate thickness: 1.
0 mm, 60 g / m ² , Al: 5% by mass) Plate F; 55% zinc aluminized 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; molten tin-zinc plated 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, Al:
50 g / m ² ) Plate N; Turn-plated steel plate (plate thickness: 1.0 mm, Pb: 4
0 g / m ² , Sn: 10 mass%)

Epoxy resin (a) The 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 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) 1950 g of a bisphenol type epoxy resin having an epoxy equivalent of 1950 is dissolved in 876 g of propylene glycol monomethyl ether, and then 78.8 g of diethanolamine is added and reacted at 100 ° C. for 3 hours to obtain a modified epoxy resin emulsion having an epoxy equivalent of 11600. It was Next, 256 g of a nonionic emulsifier (“Adeka Pluronic F68”) was added and homogenized.
53 g was gradually added and a modified epoxy resin emulsion having an epoxy equivalent of 22,500 and a solid content of 40% by weight having a primary hydroxyl group was obtained using a triaxial mixer.

(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 ( stock)
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, Mitsui Cytec Co., Ltd.)
Resin F: "Cymel 106" (fully 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-A: magnesium acetate Metal compound Mg-S: magnesium sulfate Metal compound Mn-C: Manganese carbonate Metal compound Mn-P: manganese phosphate Metal compound Mn-A: Manganese acetate Metal compound Al-P: Aluminum phosphate Metal compound Al-A: Aluminum acetate

Metal Compound Zn-P: Zinc Phosphate Metal compound Zn-A: zinc acetate Metal compound Zn-C: Zinc carbonate Metal compound Sn-P: tin phosphate Metal compound Sn-S: tin sulfate Metal compound Fe-S: iron sulfate Metal compound VS: vanadium sulfate Metal compound Ba-P: barium phosphate Metal compound Ba-S: barium sulfate

Metal Compound Co-P: Cobalt Phosphate Metal compound Co-C: Cobalt carbonate Metal compound Co-A: Cobalt acetate Metal compound Na-V: sodium vanadate Metal compound Na-Mo: sodium molybdate Metal compound KB: potassium borate

Water-repellent agent: Water-repellent agent A: "Aflon-XAD911" (fluorine resin emulsion, manufactured by Asahi Glass Fluoropolymers Co., Ltd.) Water-repellent agent B: "Aflon-QAD938" (fluorine resin emulsion, manufactured by 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 CST 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 in SST environment) Test piece 70mm × 15
After shearing to a size of 0 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) Worked material: After shearing the test piece into a size of 50 mm x 150 mm, project 9 mm of Erichsen 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 ○; 0 mm or more and 1 mm or less △; 1 mm or more and 2 mm or less ×; 2 mm or more

(Corrosion resistance of machined part in CCT environment) As a CCT condition, 8 hours 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

(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 with a cutter knife at 1 mm intervals in a grid pattern, and "Cellotape (registered trademark)" is attached 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

[0081]

[Equation 1]

[0082]

[Table 1]

[0083]

[Table 2]

[0084]

[Table 3]

[0085]

[Table 4]

[0086]

[Table 5]

[0087]

[Table 6]

[0088]

[Table 7]

[0089]

[Table 8]

[0090]

[Table 9]

[0091]

[Table 10]

[0092]

[Table 11]

[0093]

[Table 12]

[0094]

The surface-treated metal plate of the present invention is a so-called chromate-free metal plate containing no chromium,
In particular, since it is excellent in corrosion resistance, conductivity 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.

[Brief description of drawings]

FIG. 1 is a graph showing the distribution of each layer component by GDS of the surface-treated galvanized steel sheet of the present invention.

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4F100 AB01A AB01B AB01H AB02B                       AB02H AB09B AB09H AB10B                       AB10H AB14B AB14H AB17B                       AB17H AB20B AB20H AB21B                       AB21H AK53C AK80C AL05C                       BA03 BA07 BA10A BA10C                       JB02 JG01 JL11B                 4K044 AA02 AA03 AA06 AA16 BA02                       BA04 BA06 BA10 BA21 BB03                       BB04 BC02 CA16 CA18 CA53                       CA62

Claims (3)

[Claims] 1. A metal plate having an intermediate layer containing a metal (excluding chromium) on at least one side, and having an organic film formed of an epoxy resin and a glycoluril resin on the intermediate layer. A characteristic surface-treated metal plate. 2. The metal is Cu, Co, Fe, Mn, S
n, V, Mo, Mg, Ba, Al, W, Ca, Sr, Z
2. At least one metal selected from the group consisting of r, Nb, Y, Ti, Ni, Na, K and Zn.
The surface-treated metal plate according to. 3. The surface-treated metal plate according to claim 1, wherein the epoxy resin is 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.