JPH0633512B2 - Painted metal material with excellent paint adhesion, corrosion resistance, and workability, and method for producing the same - Google Patents

Description

The present invention relates to a novel coated metal material and a method for producing the same.

More specifically, the present invention relates to a novel coated metal material excellent in paint adhesion, corrosion resistance, press workability, coating film clarity, and productivity (step omitted), and a method for producing the same.

[Conventional technology]

Most of the things around us, such as automobiles, washing machines, refrigerators, and room coolers, that are made of metal are painted. Recently, as the rust resistance of these products has been improved and the service life thereof has been extended, a metal material, particularly a zinc-based plating material, has been widely used.

However, the surface of metal plating such as zinc and zinc alloy plating generally has poor paint adhesion, so that it is common to apply a coating pretreatment prior to coating. Various methods have been studied and put to practical use. Typical examples are chemical treatments (chemical conversion treatments) such as phosphate treatment and chromate treatment with a chromic acid solution, and surface irregularities such as sandblasting and grid blasting. There is a physical process etc. for giving.
All of these methods mainly expect an increase in the effective bonding surface area and an anchor effect, and are so-called surface morphology control techniques.

On the other hand, a plating film that does not require a coating base treatment is also being studied. For example, a dispersion plating method in which a water-insoluble resin is dispersed and co-deposited in a plating bath (US Pat. No. 343494).
No. 2 and No. 3461044), and this method is expected to increase the affinity of the coating with the coating material by the resin composite.

[Problems to be solved by the invention]

However, chemical conversion treatments such as phosphate treatment and chromate treatment have many problems in terms of process control and pollution prevention. That is, the phosphate treatment is most often used as a coating base treatment for a zinc-based plated metal material, but a large amount occurs not only in the length of the process (6 to 9 steps) and the bath management complexity. There are many restrictions and problems in terms of sludge and waste liquid treatment. On the other hand, the chromate treatment has not only the toxicity of chromium and problems in wastewater treatment but also the essential drawback that the paint adhesion is not always good.

Further, the inorganic oxide layer coated by such a chemical treatment has a drawback that it cannot withstand high-level pressing.

It is difficult for the physical treatment by sandblasting or the like to give fine and complicated unevenness over a wide range until the anchor effect is sufficiently exerted.

The water-insoluble resin dispersion plating method is a remarkable technique, but it is difficult to uniformly disperse and stabilize the resin particles, and it is extremely difficult to scale up, that is, it is difficult to perform uniform plating on a large-area steel strip. However, there are many problems in terms of physical properties, such as insufficient paint adhesion and poor press workability.

As mentioned above, the current technology is incomplete in plating performance and coating surface treatment technology, but as an industrial need, rust-preventive steel sheets used for automobile bodies in particular have been developed with advanced coating materials due to the recent increase in durability. There is a strong demand for rust-preventing steel plates with excellent adhesion and rust-preventing properties. Also, in the manufacturing of home appliances, from the viewpoint of labor saving, from the conventional processing / assembly → coating base treatment → coating manufacturing process (post-coated steel plate) to coating base treatment → coating → processing / assembly manufacturing process (pre-coated steel plate) The conversion is progressing to. However, the conventional chemical conversion treatment film cannot withstand severe bending and press working, and therefore thinning the chemical conversion treatment film causes a problem of adhesion of the coating material.

[Means for solving problems]

The present invention intends to complete an ideal coated metal material and a method for manufacturing the same by eliminating the above-mentioned problems relating to the production of the coated metal material by forming an ideal electroplating film. In other words, the coating pretreatment process is omitted by quantitatively measuring the essential functions such as paint adhesion and corrosion resistance of the coating metal material pretreatment layer, and imparting functions above these values to the plating film side. Then, various problems such as the pollution problem and the lack of processability that the conventional process had are solved at once. In line with the above idea, the present inventors depart from the conventional idea of improving conventional coating pretreatments such as chemical conversion treatment and blasting treatment, and the ideal chemical properties and ideal surface morphology (surface irregularities, As a result of diligently studying the crystal particle size and its shape), a water-soluble organic polymer having a certain specific chemical structure, that is, an aromatic ring having a hydroxyl group (-OH) as a directly bonded substituent, , If an organic polymer that dissolves in water and at the same time is substantially water-soluble in the plating bath is combined in the plating matrix, an electroplating film that can achieve the above objects can be obtained, and thus an ideal coated metal material can be obtained. The present invention has been found to be completed and the present invention has been completed here.

That is, the present invention has a weight average molecular weight of 10 in the plating film.
An organic polymer having a molecular weight of 100,000, and having one or more aromatic rings each having at least one hydroxyl group (-OH) as a substituent directly bonded to a molecular weight of 500, and having a molecular weight of
An average of 0.1 to 4 sulfone groups (-SO ₃ ) per 500 units, or polar groups of the following group (a) [group (a): phosphate group] (R is a hydrogen atom or a hydrocarbon group, the same applies below), phosphorous acid group Phosphonic acid group Phosphonous acid group Phosphinic acid group Phosphinous acid group Tertiary amino group Quaternary ammonium base (R ¹ and R ² are the same or different and are a linear or branched alkyl group, or a hydroxyalkyl group, or an aromatic group such as a phenyl group, R ³ is the same as R ¹ and R ² or H , X ⁻ is a counter ion, a carboxyl group (—COOH)], and one or more polar groups selected from the average of 0.1 to
The main chain connecting the aromatic rings has a CC bond, a C = C bond, an ether bond (CO-
One or more of anionic, cationic or amphoteric water-soluble organic polymers composed of any one or more of C),
Excellent coating adhesion, corrosion resistance, and workability, which is characterized by coating the surface of a metal material coated with organic polymer composite electroplating containing 0.1 to 30 wt% of the total plating weight. A coating metal material and an electroplating bath containing 10 to 600 g / one or more of metal ions are added to the electrolysis bath containing at least one of the above anionic, cationic or amphoteric water-soluble organic polymers as essential components, and the total amount thereof is A water-soluble organic polymer is obtained by electroplating with a conductive base material such as a steel plate as a cathode in a plating bath added to a range of 2 to 200 g / to co-deposit metal and water-soluble organic polymer on the surface. Of the organic polymer composite plating film is controlled so that the ratio of the above is within the range of 0.1 to 30 wt% with respect to the total eutectoid amount, and then electrodeposition coating method, electrostatic coating method, roll coating method, curtain flow coating method , Or spray coating method Various coating is to provide a method for manufacturing a coated metal material characterized by painting directly on the composite plating surface.

According to the present invention, there are the following advantages 1) to 4).

1) In order to eliminate the drawbacks of conventional electroplated coatings, especially zinc-based plated coatings, the basic skeleton of water-soluble organic polymers (aromatic rings, hydroxyl groups), the type of polar groups (such as sulfonic acid groups), and the molecular weight (1000-100 10,000) and the amount of addition to the plating bath (2-200 g /) and the plating conditions are selected to control the plating crystal particle size and morphology (miniaturization and unevenness) and increase the effective bonding area. The plating surface should be suitable for the surface of the metered coating.

2) An appropriate amount of the specific water-soluble organic polymer described in 1) and a metal are compounded at a molecular level (molecular composite), and the affinity and reaction between the plating surface and the paint are irrespective of the morphology of the plating surface. It has a chemical conversion treatment film by improving the corrosion resistance of conventional electroplating film by enhancing the adhesiveness (bonding property) and the action of the compounded organic polymer. 3) 1), 2) Succeeded in providing each function such as paint adhesion and corrosion resistance to the plating film side, and by omitting the chemical conversion treatment, the chemical conversion treatment step was completely omitted by directly coating the plating surface.

4) As a result of 3), the workability of precoated steel sheet was significantly improved by shortening the coating metal material process and significantly improving productivity and eliminating the fragile chemical conversion treatment.

The water-soluble organic polymer that can be used in the present invention is a polymer having a weight average molecular weight of 1,000 to 100,000 as group a, and at least one hydroxyl group (-OH) is directly bonded to 500 units of the molecular weight. Has at least one aromatic ring as a substituent and an average of 0.1 to 4 sulfone groups as essential components, and the main chain connecting the aromatic ring and the aromatic ring is C-
Examples of the water-soluble organic polymer include one or more of C bond, C = C bond, and ether bond (COC).

Here, poly-p-hydroxystyrene, sodium lignin sulfonate, nitrohumic acid, etc. are included in the concept of CC bond, C = C bond and ether bond (COC) of the main chain connecting aromatic rings. . Fused rings (eg It is not considered in the present invention that the above bond exists in the main chain.

The water-soluble organic polymer as used in the present invention means an organic polymer which is easily dissolved in water and is substantially water-soluble in the plating bath. When a plating bath containing such a water-soluble organic polymer is irradiated with, for example, a laser beam, no luminous flux is observed. On the other hand, in the case of a water-insoluble resin or an aqueous dispersion type (self-water dispersion type) organic polymer, when a plating bath containing them is irradiated with a laser beam, a luminous flux is observed.

In addition to the above-described functional groups, the side chains of the water-soluble organic polymers of group a include halogen groups such as Cl and Br, nitrile groups,
It may contain other functional groups such as a nitro group and an ester group.

That is, examples of the water-soluble organic polymer satisfying the above conditions include the following compounds A-1) to A-11).

A-1) Phenol formaldehyde resin (novolak resin, phenol-furfural resin, resorcin-formaldehyde resin, and sulfonates of these derivatives.

A-2) A sulfonate of an epoxy resin having a bisphenol A skeleton, an epoxy acrylate, and an epoxy resin derivative such as phenol (EO) ₅ glycidyl ether.

Bisphenol A Sodium Sulfonate, Bisphenol S
Formalin condensate of sodium sulfonate.

A-3) Polyhydroxyvinylpyridine sulfonate.

A-4) Salt of formalin condensate of creosote oil sulfate, m-cresol methylene sulfonic acid-formalin condensate, formalin condensate of m-cresol bakelite methylene sulfonic acid soda and shepheric acid, 2-
Salts of formalin condensates of alkylphenols and sulfonated derivatives of these derivatives, including formalin condensates of (2′-hydroxyphenyl) -2- (2′-hydroxy) -sulfomethylpropane salts, or phenols and phenols Salt of formalin condensate of sulfonated carboxylic acid. As phenols, phenol, o
-Cresol, m-cresol, p-cresol, 3,5
-Xylenol, carvacrol, thymol, catechol, resorcin, hydroquinone, pyrogallol, phloroglucin and the like.

Phenoliccarboxylic acids include salicylic acid, m-oxybenzoic acid, p-oxybenzoic acid, protocatechuic acid, gentisic acid, α-resorcinic acid, β-resorcylic acid, γ-.
Resorcylic acid, orseric acid, caffeic acid, umbellic acid, gallic acid, 3-oxyphthalic acid and the like can be mentioned.

A-5) A formalin condensate of a sulfonated product of mono- or polyhydroxynaphthalene and its derivative.

Examples of monohydroxynaphthalene include α-naphthol and β-naphthol. As polyhydroxynaphthalene, α-naphthohydroquinone (1,4-dioxynaphthalene), β-naphthohydroquinone (1,2-dionaphthalene), naphthopyrogallol (1,2,3-trioxynaphthalene), naphthoresilcin (1,2) 3-dioxynaphthalene) and the like.

A-6) Formalin condensate of phenylphenol sulfonate.

A-7) Formalin condensate of dihydroxydiphenyl sulfone, formalin condensate of bis (hydroxyphenyl) sulfone / naphthalene sulfonate, formalin condensate of bis (hydroxydiphenyl) sulfone monomethyl sulfonate, hydroxydiphenyl sulfone / monosulfonic acid Formalin condensate of salt.

A-8) Sulfonates of poly-hydroxystyrene derivatives such as poly-p-hydroxystyrene, poly-p-hydroxystyrene bromide, poly-p-hydroxymethoxystyrene and poly-p-hydroxydimethoxystyrene.

A-9) Lignin sulfonic acid or lignin sulfonate, which is a compound obtained by treating pulp waste liquid by-produced during pulp production by various methods, and the main component is lignin sulfonate or lignin sulfonic acid.

The chemical structure of lignin has a phenylpropane group as a basic skeleton, and this is a compound having a three-dimensional network structure.

A great number of products of lignin sulfonic acid and lignin sulfonate are manufactured and sold by pulp manufacturers. The molecular weight ranges from 180 to 100,000, and it has a wide variety of sulfonation degrees, various salts, chemically modified ones, and heavy metal ion adjusted ones. Not all of these various ligninsulfonic acids and salts thereof work effectively for the purpose of the present invention, but the effects vary greatly depending on the products. The achievement level of the object of the present invention is
It becomes maximum when using a specific lignin sulfonic acid and its salt. Therefore, there are restrictions on the preferred lignin sulfonic acid and its salts that can be used in the present invention.
That is, the present invention preferably satisfies all of the following conditions 1) to 3).

1) A low molecular weight component with a molecular weight of less than 1000 and a high molecular weight component with a molecular weight of 100,000 or more have been industrially removed, or a component with a molecular weight of less than 1000 and a component with a molecular weight of 100,000 or more is very small, and the peak of the molecular weight distribution is from 1000 to It has a duration of 100,000, and at least 50% or more of its components are present in this molecular weight range.

2) An average sulfo group density (degree of sulfonation) of 0.6 to less than 3 per 500 units of molecular weight.

3) Those that do not artificially increase the number of carboxyl groups by applying oxidation treatment (normal lignin sulfonate contains about 0.5 carboxyl groups per 500 units of molecular weight).

The type of lignin sulfonate salt that can be used in the present invention is not particularly limited, and any of Na salt, K salt, Ca salt, ammonium salt, Cr salt, Fe salt, Al salt, Mn salt, Mg salt and the like can be used. It can be used in the present invention, but those satisfying the above conditions 1) to 3) are preferable.

Further, lignin sulfonic acid and lignin sulfonate obtained by chelating heavy metal ions such as Fe, Cr, Mn, Mg, Zn and Al can also be used in the present invention, but those satisfying the above conditions 1) to 3) are preferable.

Further, ligninsulfonic acid and ligninsulfonic acid salt to which another organic compound such as naphthalene or phenol or an organic polymer is added can be used in the present invention, but those satisfying the above conditions 1) to 3) are preferable. By the way, the lignin sulfonic acid and its salt that can be used in the present invention may contain impurities during pulp production, but the smaller the amount, the more preferable.

The amount of lignin sulfonic acid and its salt added to the plating bath may be in the range of 2 to 200 g / net as a net amount excluding impurities, but preferably in the range of 3 to 100 g /.
The most preferable range is 5 to 50 g /. Even if the amount added is less than 2 g / minute, the crystal can be made finer and the plating surface can be made uneven, but the chemical properties of the plating surface (adhesion (bondability) to the coating material) are not sufficiently improved. On the other hand, if it exceeds 200 g /, the plating film becomes brittle and the workability deteriorates, which is not preferable. 2-200g /
It is possible to achieve the same or higher level of primary and secondary adhesion of the coating that has been treated with phosphate, which is said to be the best in the coating base treatment, with the addition amount of 3 to 100 g / Both secondary and secondary (water-resistant) adhesion and corrosion resistance after coating can be achieved with properties that greatly exceed those treated with phosphate. With an addition amount of 5 to 50 g / mole, not only the coating primary and secondary adhesion but also the corrosion resistance after coating can be remarkably improved under a wide range of plating conditions.

The present invention is characterized in that a water-soluble organic polymer such as lignin sulfonic acid and a salt thereof can be added to and mixed with a plating bath alone to achieve a desired effect. For example, in addition to essentially not requiring a plurality of formulations such as a first brightener, a second brightener and a third brightener (quick brightneer) as found in a brightener composition, the conventional brightener is generally used as a brightener. If gelatin, saccharin, molasses, polyethylene glycol, polyethylene glycol nonylphenyl ether, benzoquinone, oleic acid, fluorotriacetic acid, etc. are added, the effect of the present invention may be significantly reduced.

The reason for setting the above restrictions 1) to 3) is that the factors in the conditions 1) to 3) above significantly affect paint adhesion, corrosion resistance, and finer crystal grains and unevenness of the plating surface. To give. That is, 1) although the crystal particles are made finer in the low molecular weight ligninsulfonic acid and its salt of less than 1000, the paint adhesion,
In particular, the improvement of secondary (water resistant) adhesion is insufficient, and high-molecular-weight ligninsulfonic acid of 100,000 or more and its salt have poor solubility in the plating bath and the adhesion of paint (1
This is because it is difficult to sufficiently obtain the following improvements.

2) The sulfonation degree is limited to less than 0.6 (molecular weight 500 units)
This is because the solubility in the plating bath is lowered and the amount added to the plating bath is limited, and it is difficult to achieve finer crystals or complicated surface irregularities.

3) The limitation of the carboxyl group is that the secondary (water resistant) adhesion of the coating tends to be deteriorated when the number of carboxyl groups in ligninsulfonic acid and its salt is increased.

However, in any case, since the ligninsulfonic acid-based organic polymer has a production lot deviation of its quality (with respect to the effect of the present invention), careful consideration is required for industrial implementation of the present invention. is there.

A-10) Sulfonated products of polytannic acid and its derivatives.

A-11) Sulfonates of humic acid or nitrated humic acid and their derivatives or their salts.

Further, examples of the water-soluble organic polymer that can be used in the present invention include the following group b.

Group b: an organic polymer having a weight average molecular weight of 1,000 to 100,000, and one or more hydroxyl groups per 500 molecular weight units
Having one or more aromatic rings with (-OH) as a directly bonded to a substituent, and the average in the unit 0.1-4 sulphonic group (-SO _3), or phosphate group (R is a hydrogen atom or a hydrocarbon group, the same applies below), phosphorous acid group Phosphonic acid group Phosphonous acid group Phosphinic acid group Phosphinous acid group Tertiary amino group Quaternary ammonium base (R ¹ and R ² are the same or different and are a linear or branched alkyl group, or a hydroxyalkyl group, or an aromatic group such as a phenyl group, R ³ is the same as R ¹ or R ² , or H , X ⁻ is Cl, Br, I or a counter ion such as an organic acid anion and an inorganic acid anion), and one or more polar groups selected from a carboxyl group (—COOH) as an essential component on average 0.1 to
The main chain having 5 ranges and connecting the aromatic ring and the aromatic ring is
An anionic, cationic and amphoteric water-soluble organic polymer composed of at least one of CC bond, C = C bond and ether bond (COC).

In addition to the above polar groups, the side chains of the water-soluble organic polymers of group b also contain other functional groups such as halogen groups such as Cl and Br, nitrile groups, nitro groups, ester groups, and amide groups. But it's okay.

That is, examples of the water-soluble organic polymer group b satisfying the conditions include the following polymers B-1) to B-4).

B-1) An anionic or amphoteric type in which one or more polar groups selected from the following group (I) are introduced into the matrix of the water-soluble organic polymer of A-1) to A-11) described above. Type water-soluble organic polymer.

Group (I) polar group: tertiary amino group, quaternary ammonium group, carboxyl group, phosphoric acid group, phosphorous acid group, phosphonic acid group, phosphonous acid group, phosphinic acid group,
A phosphinic acid group.

Or among the organic polymers of A-1, A-2, A-3, A-4, A-8, A-9, A-10, A-11, the organic polymer before sulfonation is An anion type or a cation type in which one or more polar groups selected from the above group (I) are introduced into the raw material,
Amphoteric water-soluble organic polymer.

Alternatively, one of the formalin condensates of A-4, A-5, A-6, and A-7, which has been modified to have no sulfone group as a raw material. That is, A-4 ': a formalin condensate of phenol, phenolcarboxylic acid, or alkylphenol and derivatives thereof.

A-5 ': Formalin condensate of mono- or polyhydroxynaphthalene and their derivatives.

A-6 ': Formalin condensate of phenylphenol.

A-7 ′: Formalin condensate of dihydroxyphenyl.

Using these A-4 'to A-7' polymers as raw materials, group (I)
Anionic, cationic, and amphoteric water-soluble organic polymers in which one or more polar groups selected from the above are introduced.

B-2) A copolymer of poly-p-vinylhydroxystyrene and maleic anhydride. This copolymer is further aminated or phosphorylated.

B-3) Sulfonates of formalin condensates of phenylphosphonic acid and its derivatives with phenol and its derivatives or resorcin or its derivatives, and salts thereof.

Examples of the derivative of phenylphosphonic acid include monooctylphenylphosphonate, diphenylphosphonic acid, o-methylhydrogenphenylthiophosphonic acid, and diphenylphosphinic acid.

As the derivative of resorcin, 2,6-dihydroxyacetophenone, 2,4-dihydroxyacetophenone, resorcinol monomethyl ether, resorcinol monohydroxyethyl ether, 2-methylresorcinol, 7
-Hydroxy-4-methylcoumarin, 2-ethylresorcinol and the like can be mentioned.

As the derivative of phenol, all of the phenols, phenolcarboxylic acids and alkylphenols described in A-4) can be mentioned.

B-4) Humic acid, nitrohumic acid and salts thereof, or amination products of the above humic acids, from each of the groups A and B above, or A,
It is also possible to select one kind or two or more kinds from both groups B and mix them. The type of salt of the organic polymer may be any of Na salt, Ca salt, NH ₄ salt and the like and is not restricted.

The water-soluble organic polymer that can be used in the present invention has a weight average molecular weight in the range of 100 to 100,000, preferably 1,000.
To 500,000, most preferably 200,000 to 100,000. The reason for this is that the molecular weight of the organic polymer influences the effect of the present invention, and it is difficult to obtain a large paint adhesion effect with a low molecular weight substance having a molecular weight of less than 1000, but on the other hand, with an organic polymer having a molecular weight of more than 1 million, the plating bath is used. Has poor solubility,
This is because the concentration added to the plating bath is limited and becomes a problem, and at the same time, the effects of the present invention are difficult to obtain. Considering the easiness of exhibiting functions such as solubility in a plating bath and adhesion of a paint, the weight average molecular weight is most preferably in the range of 200,000 to 100,000.

The polar group (not including a hydroxyl group or an aromatic ring) of the group a such as a sulfonic group or a phosphoric acid group gives the solubility of the organic polymer in the plating bath, the crystal grain size of the plating is miniaturized, and the surface is roughened. Is particularly important, and the preferable range of the polar group density is such that the average sulfonic group per molecular weight of 500 is 0.1 to 4
The number of polar groups of group a is 0.1 to 5 on average, and more preferably 1 to 3. When the polar group density is less than 0.1, the solubility in the plating bath is poor, which causes a problem. When the number of sulfone groups exceeds 4 and the number of polar groups of group a exceeds 5, the corrosion resistance of the obtained plating film deteriorates. Because it will be. The polar group is most preferably a sulfone group or an amino group. The reason is that those having a sulfone group or an amino group exhibit the best paint adhesion. The presence of a hydroxyl group and an aromatic ring is an essential constituent component of the organic polymer for the bath of the present invention in terms of improving coating adhesion and improving corrosion resistance after coating.
And since bulky is preferable, the number present in one molecule is important. The greater the number of hydroxyl groups contained in a molecular weight of 500 units (up to 10), the better, and the number of aromatic rings is preferably 2 or more. Count one). It is preferable that the hydroxyl group is directly attached to the aromatic ring as a substituent because the effect is well exhibited.
The main chain connecting the aromatic rings does not contain a heteroatom C-
Most preferred are those composed of C, and C = C bonds,
COC binding is then preferred. Those containing an ester bond (O · CO) or an amide bond (CONH ₂ ) in the main chain are not preferred in the present invention. The reason is that the secondary (water resistant) adhesion of the coating cannot be sufficiently improved with a resin containing an ester bond or an amide bond in the main chain. It is considered that this is because there is a problem in the stability of the bond such as hydrolysis due to decomposition and deterioration at the time of electrolysis and baking of the paint, or hydrolysis due to pH increase (pH 12 or more) during corrosion under the coating film. The molecular weight of the above water-soluble organic polymer,
Factors such as structural units, types and densities of polar groups, types of main chains, etc. are important factors that play an essential role in the plating film of the present invention and the method for producing the same.

As the base plating bath that can be used in the present invention, generally known or new plating baths can be used, but an acidic bath can be used as a preferable bath. A zinc plating bath or a zinc alloy plating bath is particularly preferable. The galvanizing bath includes a known galvanizing bath containing 10 to 600 g / zinc ion, such as (1) a sulfate bath using zinc sulfate, a chloride bath using zinc chloride, a borofluoride bath, or a mixed bath thereof. Commonly known acidic bath, (2) neutral bath prepared by neutralizing zinc chloride with ammonia, (3) zinc pyrophosphate bath using zinc pyrophosphate, zinc, zincate bath made of sodium hydroxide, etc. Or, a general well-known zinc plating bath such as (4) zinc cyanide plating bath can be mentioned, and of these, (1) is preferable.

The base zinc alloy plating bath that can be used in the present invention includes iron, nickel, chromium, cobalt manganese, copper, tin and lead which are considered as alloying elements in the above zinc plating baths (1) to (4). 1 to 600 g of one or more elements selected from chlorides, sulfates, fluorides, cyanides, oxides, organic acid salts, phosphates or simple metals, etc. A general publicly known or new zinc alloy plating bath added with / can be used. Of these, the bath constructed based on the bath (1) is preferable.

The amount of water-soluble organic polymer added to the plating bath is 2-200 g /
, Preferably 3 to 100 g /, most preferably 5 to 50 g / added plating bath. The reason for this is that when the amount added is less than 2 g /, the crystal grain size of the plating and the unevenness of the plating surface can be achieved to some extent, but the chemical characteristics of the plating film (for example, the primary and secondary adhesion (bondability) to the coating) Improvement not fully achieved, while 200
If it exceeds g /, the plating film becomes brittle and causes problems during press working. To achieve a well-balanced function including the primary adhesion of the paint, the secondary (water resistant) adhesion, and the bare and corrosion resistance after painting, and processability
Addition amount of 0 g / is preferable, most preferably 5 to 50 g
In this range, the above-mentioned functions can be realized under a wide range of plating conditions.

The plating bath used in the present invention is the simplest plating bath containing necessary amounts of metal ions, a pH buffering agent, and a pH adjusting agent, and one of the above-mentioned specific water-soluble organic polymers (1
One or more) may be added alone and blended alone to achieve a sufficient purpose, and essentially no other plating bath auxiliary agent is required to be added. On the contrary, rust preventives, brighteners, pit preventives, mist preventers,
When an auxiliary agent (organic compound) such as a defoaming agent is added, many of these organic compounds or organic polymer auxiliary agents, for example, α-naphthalenesulfonic acid, isooctyl polyoxyethylene ether, gelatin, coumarin, Auxiliaries commonly used in the past, such as Propagil Alcoh,
Since there is a risk that the essential function of the plating film of the present invention is significantly deteriorated, it is necessary to pay close attention to the compounding amount and the like when using it.

Since the organic polymer is stably dissolved in the plating bath used in the present invention after the bath is adjusted, it is not necessary to stir the liquid for homogenizing the dispersion, and the scale-up can be easily performed.
Please note that the solubility of the water-soluble organic polymer used may deteriorate depending on the pH and metal ion concentration of the plating bath.

The plating conditions are preferably a current density of 1 to 800 A / dm ² and a bath temperature of 1 to 80 ° C. The pH of the plating bath can be used in the range of pH 1 to 12, but it is preferably on the acidic side. A direct current is preferable as the electrolysis current, but a pulse current or a special waveform current can also be used. Agitation of the plating bath is important when performing high-speed plating, and in the case of high-speed continuous plating of steel strip, agitation at a relative speed (between plate and plating bath) of about 90 to 120 m / min is desirable.

Since the method for producing an organic polymer composite plating film according to the present invention uses a water-soluble polymer, it has a great feature in that the complexation with the eutectoid metal occurs on the molecular order, and the macroscopic dispersion / This is a major difference between the present invention and the conventional dispersion plating for co-depositing water-insoluble particles, which can achieve only complex formation.

The content of the water-soluble organic polymer in the plating film is in the range of 0.1 to 30% by weight, preferably 0.2 to 15% by weight, based on the total weight of the plating film. If the amount of co-deposition of the organic polymer is small, it is close to metal simple plating, so that the paint adhesion effect and rust preventive effect are difficult to appear. On the other hand, if it is too large, the plating film becomes brittle and the pressless workability deteriorates, which is a problem. Considering the balance among the functions of paint adhesion, corrosion resistance, and press workability, the preferred range of co-deposition of organic polymer is 0.2-15wt%, and the most preferred co-deposition of organic polymer is 0.5-5wt. It exists in the range of%.

The co-deposition amount of the water-soluble organic polymer depends on the polymer concentration, current density,
It is mainly changed by stirring and the charge of the organic polymer. The amount of eutectoid increases with high concentration, high current density, and strong stirring. If the molecular skeletons are almost the same, the amount of eutectoid is in the order of cationic polymer> amphoteric polymer> anionic polymer. Therefore, at the time of plating, the eutectoid amount of the organic polymer in the plating film is controlled by selecting each of the above factors, but this control can be achieved quite easily.

A second object of the present invention is to control the plating crystal particle size and its morphology by the action of the water-soluble organic polymer to mainly improve the coating adhesion and the corrosion resistance. This is expected to increase the effective bonding surface area due to the refinement of crystal grains (not to mean smoothing) and to promote the unevenness of the surface to exhibit the anchor effect.
Therefore, there are the following two directions here. One is to make the crystal grain size finer (which does not mean smoothing) to increase the effective bonding surface area. The other one is that the crystal may be coarse, so that the crystal growth in a specific orientation plane is controlled, and for example, a scaly crystal shape is formed into a plating film in which it is three-dimensionally intertwined, and the anchor effect is This is the direction of forming a surface morphology that is easily expressed. Of course, there may be a combination of these two directions. Among these, those which have a complicated surface shape and are expected to have an anchoring effect even if the crystals are coarse are good in terms of the primary adhesion of the coating, but in terms of the secondary (water resistant) adhesion and corrosion resistance, the crystal grain size It is often worse than the miniaturized one. It is considered that this is because the plating film is not dense.

The crystal size of the plating film used in the present invention is 10μ to 50Å
The range of is good. However, the crystal grain size referred to here is the average value of the longer one of the x, y and z axis lengths of the grain. The relationship between the crystal grain size and the paint adhesion tends to show excellent paint adhesion unless the plating film having a crystal particle size of about 10 to 2 μ has a complicated surface morphology in which an anchor effect can be expected. Even if the plating surface shape is not three-dimensionally complicated, when the crystal particle size is 2 μm or less, the paint adhesion effect begins to be exhibited and becomes remarkable at 5000 Å or less, and the best paint adhesion is obtained in the range of 1000 to 50 Å. The effect of increasing the effective bonding surface area is less than 5000Å, especially 1000
It is thought that this is due to the remarkable effect below Å.

The primary adhesion of the paint depends on the paint used. There is a large variation in chemical conversion treatments. For example, when using an epoxy-based cationic electrodeposition coating, a phosphate-treated zinc-based plated steel sheet has an average order of 30 to 50kg / cm ² , chromate treatment. It is an average of 20-40kg / cm ² for the zinc-based plated steel sheet. The adhesion force is measured by adhering a cylindrical jig with Araldite on the surface of the coating film and using a weight tensile tester (Pulgarge 1000M manufactured by Moto Fuji Co., Ltd.). When powdered polyester coating is used, the average is 40-
60 kg / cm ^2, the order of the average 30 to 50 kg / cm ² at a zinc-plated steel sheet subjected to chromate treatment. When solvent-based polyester paint is used, the value is the same as or slightly lower than that of powder polyester paint. As described above, there is a difference depending on the type of paint, but in order to give the primary adhesion of paint that is comparable to the plated steel sheet that has been subjected to chemical conversion treatment such as phosphate treatment or chromate treatment, 50-60 kg / cm ² or more is required. It is understood that the coating film itself should have adhesion to the paint. In the present invention, a water-soluble organic polymer having a specific chemical structure that imparts a paint adhesion effect is blended in a plating bath to control the resulting plating surface morphology and crystal grain size, and to eutect the polymer on the plating matrix. By making a composite plating film that is highly bondable (reactive) with the paint, we succeeded in realizing a coated metal material that has a paint adhesion of 60 kg / cm ² or more without the conventional chemical conversion treatment. Is. In addition, if the adhesive strength of the paint is 100 kg / cm ² or more, it is possible to further reduce the quality of the paint or omit the primer paint for the undercoat depending on the adhesive strength. That is, it is possible to manufacture a coated metal material with a reduced coating cost, which further increases its industrial value. Further, in the paint metal material of the present invention, since the brittle inorganic oxide layer is not interposed between the coating film and the material to be coated, the strength is that the strong adhesive force formed between the plating surface and the paint can be maintained as it is. Therefore, this point brings an extremely great merit in practical use. For example, it becomes resistant to external forces such as shocks, and at the same time it can withstand severe press working after painting. Use of precoated steel sheet (pressable coated steel sheet), which has attracted attention in the home appliance industry, exerts this advantage to a great extent. be able to. Further, the paint adhesion of the coated metal material of the present invention is one of the major characteristics in that the dispersion due to the production lot and the dispersion due to each part of the test method are less than those obtained by the chemical conversion treatment.

As a result of examining the secondary (water resistant) adhesion of the paint, it was found that even if it was continuously immersed in ion-exchanged water with a specific resistance of 50 Ω / cm or more at 60 ° C, and it was 100 times even after 100 days even if it exceeded 100 days.
If you clear / 100 (no peeling), it will surpass the one with the best phosphate treatment as a conventional coating base,
It has been found that it can be a coated metal material having a secondary adhesion that can withstand even in an actual use environment. Further, if it is a composite plated material having a secondary adhesion of 100/100 (without peeling) even after exceeding 150 days, it is possible to reduce the quality of the coating material and omit the primer.

By the way, only increasing the physical effect due to the refinement of the crystal grain size and the complicated plating surface (anchor effect) is extremely effective for the primary adhesion of the coating, but not necessarily for the secondary (water resistant) adhesion. Not guaranteed. This is because in a wet environment, the alkali generated under the coating film dissolves the plating film and breaks the chemical bonds in the coating film. Therefore, in order to guarantee the functions up to the secondary adhesion and corrosion resistance, it is necessary to make the plating film alkali resistant or to improve the chemical characteristics of the plating film. It is important from this point as well to form a molecular composite of a water-soluble organic polymer in a plating matrix, and in the present invention, a composite surface of a specific water-soluble organic polymer can realize a plating surface with low alkali solubility.

The coated metal material of the present invention enhances the bondability (reactivity) with the coating material on the plating surface, the bond density and its strength by the effect of combining a specific water-soluble organic polymer in the plating film, and the plating surface Due to the alkali resistance, the water-resistant adhesion of the coating is 100/100 even after 100 days or 150 days of immersion.
It is an improvement of the goggles (without peeling) -cellophane tape peeling test until it can be cleared.

The results of examining the corrosion resistance of electrogalvanized steel sheets that have been subjected to conventional chemical conversion treatment after coating are as follows. The test method is as follows: After coating with various paints, a test piece with crosscut scratches is continuously sprayed with a 5% sodium chloride aqueous solution for 2 weeks based on JIS 2371, and dried at room temperature. I went. As a result of using an epoxy-based cationic electrodeposition coating, the maximum peeling width (one-sided width) of the coating film was obtained when the material to be coated was a phosphate-treated electrogalvanized steel sheet.
Approximately 3.5 mm, when chromate treatment is applied, approximately 3.5 mm, when powdered polyester paint is used, the electrogalvanized steel sheet whose phosphate coating is applied is the maximum peeling width (single width) 2mm, about 3.5m with chromate treatment
It was m. The order was almost the same for the thermosetting solvent polyester paint and the epoxy resin paint. In order to have corrosion resistance after coating that is equal to or higher than that of the plated steel sheet that has undergone chemical conversion treatment such as phosphate treatment or chromate treatment, in the above corrosion resistance test method, the peeling width of the coating film should be within 2 mm on each side.
It is understood that it is preferable to keep the peeling width smaller.

Similar to the improvement of the secondary adhesion of the coating material, the coated metal material of the present invention has a bonding property with the coating material on the plating surface by incorporating a water-soluble organic polymer having a specific chemical structure in the plating film ( Reactivity), bond density and its strength are increased, and at the same time, the plating surface is made alkaline resistant to improve the corrosion resistance after coating. As a result, the maximum peel width is at least 11 in the above test method.
A coated metal material that can be kept within mm has been born. When the effects of the present invention are sufficiently brought out, a peeling width of 0.5 mm or less can be realized.

In the present invention, the target metal material to be coated is not particularly limited. For example, a steel plate, a copper plate, a brass plate, or the like on which organic polymer composite plating is applied can be used, but a steel plate is preferably used. In addition, a material obtained by processing and assembling a metal material plated with an organic polymer composite (before entering the phosphate treatment step), for example, an automobile body (white body) is also within the scope of the metal material to be coated of the present invention. included.

By the way, the use of water-soluble organic compounds for electroplating has been performed for a long time. This is because a relatively low molecular weight surfactant is used as a plating bath auxiliary agent in a very small amount (0.001 to 0.0
5%) Addition mainly improves decorativeness (brightener)
Is aimed at. For other purposes, it is used as an anti-mist agent, an impurity removing agent (complex forming agent), an antifoaming agent, an insoluble suspending agent, an aggregating and precipitating agent for impurities, or a dispersant for eutectoid particles in the dispersion plating method. ing.
Therefore, in the above case, it is often observed that the coating adhesion and the corrosion resistance as in the present invention are not improved or, on the contrary, deteriorated due to the water-soluble organic compound used as the auxiliary agent. In the past, since these surfactants often had poor plating properties (fragility, corrosion resistance, etc.), the amount added was kept as low as possible, and they were usually used at extremely low concentrations. Thus, although there are few organic compounds or types that have been used conventionally, gelatin, saccharin,
Since organic polymers such as molasses have a problem in their chemical structure, even if they were positively incorporated into the plating bath and incorporated into the plating film, no significant advantage other than the gloss effect was obtained. The present invention is largely different from the conventional purpose of use, and is mainly aimed at improving paint adhesion and corrosion resistance, and therefore the method of use is also different. For example, a brightener generally has an effect only when three components such as a first to a third brightener are blended, whereas in the present invention, one component of a water-soluble polymer can sufficiently achieve the purpose. In the present invention, the above-mentioned function is exhibited by positively co-depositing and complexing a plating metal and a water-soluble organic polymer having a specific chemical structure which has never been seen.

With the composite plating film of the present invention, since it is possible to directly coat the plating surface without any coating base treatment such as phosphate treatment, chromate treatment or blast treatment that is generally performed conventionally, there is no problem of pollution caused by coating base treatment. It is possible to free from various problems such as complexity of process control and easily achieve labor saving and energy saving.

As the coating method, known coating methods such as electrodeposition coating, electrostatic spray coating, spray coating and roll coating can be applied.

The coating material that can be used in the present invention is not particularly limited, but either a thermosetting coating material, a room temperature drying coating material, an ultraviolet ray (UV) curing type coating material, an electron beam (EB) curing type coating material, etc. But you can use it. For example, for electrodeposition paints, epoxy resin-based cationic electrodeposition paints, polybutadiene resin-based anion electrodeposition paints, etc., for powder coatings, polyester-based paints, acrylic resin-based paints, etc .; for solvent-based thermosetting paints, polyester Paint, epoxy resin paint,
Acrylic resin paint, melamine alkyd resin paint,
As the epoxy resin-based zinc rich paint and the like, as the room temperature dry type paint, generally available products such as acrylic resin-based paint and epoxy resin-based zinc rich paint can be used. A coating using a blocked isocyanate compound as a cross-linking agent of the coating is preferable, and examples thereof include an epoxy resin-based cationic electrodeposition coating, a powder polyester coating, and a solvent polyester coating. The effects of the present invention are best exhibited when these paints are used. It is considered that this is because the reaction proceeds between the active hydrogen (hydroxyl group) of the water-soluble organic polymer co-deposited during the composite plating and the isocyanate group in the coating material to facilitate the formation of a strong urethane bond.

In the present invention, when performing electrodeposition coating using the composite plated material of the present invention particularly when performing electrodeposition coating, compared with those subjected to chemical conversion treatment such as phosphate treatment or chromate treatment,
Current efficiency is about 30% better (30% thicker coating can be obtained with the same amount of electricity) and more dense and smooth electrodeposition coating with few pinholes can be obtained. This is because the chemical conversion treatment film is electrically insulating and has a porous surface, so the effective area through which the current flows is small, the effective electrodeposition current density is high, and gas generation is concentrated locally. )
It is thought that this is because the number of holes increases and the number of pinholes increases. Since the composite plating surface of the present invention is almost an electrically conductive surface, the above-mentioned problems do not occur because the effective current density is low and gas generation is dispersed.

[Action]

The coated metal material of the present invention has the following characteristic actions 1) to 4).

1) As the material to be coated is a metal material that has been subjected to composite plating of an organic polymer, the compatibility of the paint with the action of the water-soluble organic polymer compounded in the plating film in a molecular order micro
Increased connectivity (hydrogen bonds, chelate bonds, etc.) is obtained. As a result, extremely excellent paint adhesion and secondary (water resistant) adhesion functions are exhibited.

2) Corrosion resistance increases due to the insulating effect or rustproof property of the water-soluble organic polymer co-deposited in the composite plating film, that is, in the plating crystal grains and grain boundaries.

3) In addition, the finer crystals and unevenness of the plating surface increase the effective surface area and develop the anchor effect to improve paint adhesion, and the finer crystals result in a dense film and improved corrosion resistance. To do.

4) Due to the synergistic effect of 1) and 2), even better paint adhesion,
It becomes a plated metal material with excellent corrosion resistance.

Further, according to the method for producing a coated metal material according to the present invention, the plating matrix is formed by the interaction of the molecular weight of the water-soluble organic polymer compounded in the plating bath, the basic skeleton, the type of polar group and its density, the compounding concentration and the electrolytic conditions. The eutectoid amount of the water-soluble organic polymer in the inside is determined. Further, the above-mentioned interaction can control the plated crystal particle diameter and its shape, and in particular, the molecular weight, the kind of polar group and its density have a great influence on the crystal particle diameter and shape. By directly coating the surface of such composite plating, a more positive reaction (bonding) with the coating material occurs, resulting in a coated metal material having excellent coating adhesion and corrosion resistance after coating.

〔Example〕

 Hereinafter, the present invention will be described in more detail with reference to examples.

Example 1 (1) Plating Method Pretreatment: The cold rolled steel sheet was subjected to alkaline electrolytic degreasing, water washing, and plating under the following conditions.

Plating bath: The composition of the plating basic bath used is shown in Table 1, and the type of water-soluble polymer is shown in Table 2. The composition of the organic polymer composite plating bath in which these are combined is shown in Tables 4 and 5.

Plating conditions: Plating was performed at a bath temperature of 30 to 60 ° C. using a direct current with a current density of 4 to 200 A / dmkg / cm ² . The plating film thickness was all 3 μm. An overcurrent type film thickness meter (Sanko Denshi Co., Ltd., SL-2L-SM type) was used for film thickness measurement.

(2) Coating method Table 3 shows the coating material, coating method and coating conditions used. The coating was performed directly on the plated surface except for the comparative product, which had been subjected to chemical conversion treatment.

For the phosphate treatment and the chromate treatment of the chemical conversion treatment of the comparative product, a zinc phosphate treatment of Bonderite 3004 manufactured by Nippon Parkerizing Co., Ltd. and a chromate treatment chemical manufactured by Nippon Paint Co., Ltd. ((Granosine 92)) were used.

(3) Evaluation of Corrosion Resistance Using a salt spray tester manufactured by Itabashi Rika Co., Ltd., 5% NaCl was continuously sprayed for 2 weeks based on JIS 2371.

(4) Press workability It was evaluated using an Erichsen extrusion tester, press working tester, roll form and bending tester.

(5) Results Table 4 shows the preparation conditions of various coated steel sheets of the present invention, the functions of the coating film primary adhesion, secondary (water resistant) adhesion, and post-coating corrosion resistance together with comparative products.

In the coating film adhesion evaluation result by the goggles test, no significant difference is found between the product of the present invention (No. 1 to 80) and the comparative product (No. 81 to 125).

However, it can be seen that there is a significant difference in the coating film adhesion evaluation results under severe conditions by the Erichsen extrusion test. That is, first, Zn containing no organic polymer
Compared with the case where the alloy plating film is used as the coating base (No. 81 to 90), the coating adhesion of the product using the organic polymer composite invention product as the coating base (No. 1 to 80) is higher. It turns out that it is extremely excellent. Next, comparative products Nos. 92 to 99, 101 to 106, and 109 to 113 show cases in which a plating film containing a water-soluble organic polymer that does not satisfy the conditions of the present invention is used as a coating base. When using these plating films as the base,
The primary adhesion of the paint may be improved as compared with the one using pure zinc or a pure zinc alloy plating film as a base, but it is found that it is significantly inferior in function when compared with the product of the present invention. . In addition, even when the plating bath contains a water-soluble organic polymer satisfying the conditions of the present invention, when using a composite plating film with a small amount thereof and a small amount of eutectoid to the plating film (No. 91) It is found that the improvement in paint adhesion is not sufficiently achieved. Furthermore, even if the plating bath contains a water-soluble organic polymer satisfying the conditions of the present invention, a plating bath (No. 100, 107, 108) in which an organic additive which does not satisfy the conditions of the present invention is simultaneously mixed is used. It can be understood that there are cases where the effects of the present invention are not sufficiently exhibited in the plating film thus obtained. Next, when the plated steel sheet (No. 117 to 125) subjected to chemical conversion treatment and the product of the present invention were compared, all of the products of the present invention exhibited a primary coating film adhesion superior to that of the comparative product.

According to the results of evaluation of water-resistant adhesion, the product of the present invention (No. 1 to 8)
0) is a comparative product of Nos. 81 to 90 containing no organic polymer and N
Comparative products, such as the case of using a water-soluble organic polymer which does not satisfy the conditions of the present invention of o.
It was found to outperform or equal the performance of any of the 125) comparative products. Also, using the type of paint that is originally used for 2 coats and 2 bake (primer + top coat),
No.39 (invention product) and No.121 (comparative product) when the primer layer is omitted and the topcoat is applied suddenly.
Shown in. It can be seen that the chemical conversion treated product of the comparative product cannot maintain the water-resistant adhesive strength for a long period of time, whereas the product of the present invention still exhibits excellent water-resistant adhesiveness even if the primer is omitted.

From the above results, it was found that a coated steel sheet excellent in paint adhesion can be prepared by using a zinc-based plated steel sheet composited with a water-soluble organic polymer as a coating film base.

Regarding corrosion resistance, the products of the present invention (No. 1 to 80) are comparative products (No.
81 to 125), and the coated metal material of the present invention has a remarkable effect in improving the corrosion resistance.

In Table 5, the coating adhesion of the product of the present invention is quantified, and the evaluation results including the workability and the corrosion resistance after processing are shown together with the comparative product. When the pure zinc or pure zinc alloy plating film was used as the coating base (No. 147 to 148), the comparative product contained the organic polymer satisfying the conditions of the present invention in the plating film even if it was contained in the plating bath. When a plating film with insufficient or excessive deposition is used as a base (No. 149, 150), when a plating film co-deposited with an organic polymer that does not satisfy the conditions of the present invention is used (No. 151, 153, 154), even when the plating bath contains a water-soluble organic polymer satisfying the conditions of the present invention, an organic additive which does not satisfy the conditions of the present invention is simultaneously mixed (No. 15).
2) When using a plating film that has been further subjected to chemical conversion treatment (N
15-158).

The paint adhesion (vertical tensile test) of the coated metal material of the present invention is ◎ (100 kg / cm ² or more) or ◯ (60-100 kg / cm ² ).
It was found that each of them had an adhesion force higher than that of the comparative product. In terms of the functions of water-resistant adhesion, workability in roll form test and press working test, and further, corrosion resistance after processing, corrosion resistance after painting, the product of the present invention sufficiently expresses the intended function, and all are compared. It turned out to exceed the product.

It can be seen from Tables 3, 4, and 5 that the various functions of the coated metal material of the present invention described above are somewhat different depending on the coating material used, but the essential effects are not dependent on the coating material and coating method.

As mentioned above, by applying a water-soluble organic polymer having a specific chemical structure to electroplating, it is possible to overcome the drawbacks of the conventional zinc-based plating film. By using as a paint adhesion and corrosion resistance without applying chemical conversion treatment technology,
It was found that a coated metal material excellent in press workability can be obtained.

Since the coated metal material of the present invention is particularly excellent in paint adhesion and corrosion resistance after coating, it can be an extremely excellent rust-preventing steel plate when applied to a rust-preventing steel plate for automobiles.

Further, the composite plating film of the present invention is not only a paint but also a rubber,
It can also be used as the surface of a laminate base for organic films, ceramics, etc.

Further, in the production of the water-soluble organic polymer composite plating film according to the present invention, it can be easily produced by the conventional electroplating equipment and coating equipment, does not require expensive equipment and much labor, and has a high industrial value.

The composite plated metal material that is the material to be coated of the present invention may be coated after chemical conversion treatment. In this case, the organic polymer slightly dissolved from the composite plating film is incorporated into the chemical conversion treatment film during chemical conversion treatment, so a coating with better paint adhesion and corrosion resistance than the chemical conversion treatment film formed on the pure zinc-based plating surface. An undercoat is formed.

[Effects of the Invention] As described above, the present invention has a great feature in using a plated metal material in which a water-soluble organic polymer having a specific chemical structure is used as a material to be coated. Since this composite plated metal material is a composite of the plated metal and an organic polymer on a molecular order, it has excellent reactivity (bondability) with the paint, and if the surface is directly painted, a high level of paint adhesion,
Corrosion resistance after painting, that is, it is possible to directly paint without applying any coating base treatment (chemical conversion treatment) such as phosphate treatment or chromate treatment that has been commonly used in the past. Can be omitted. This industrial merit is enormous. Furthermore, since it is possible to manufacture a coated metal material without a fragile chemical conversion coating, it is possible to manufacture an ideal precoated steel sheet for home appliances or building materials, which is excellent in press working after coating.

The combined effect of the organic polymer according to the present invention is effective for all electroplating, but is more effective particularly when a zinc or zinc alloy plating matrix is used, and the metal material to be plated is iron or steel plate. Works most effectively when.

Claims (12)

[Claims] 1. The weight average molecular weight of the plating film is from 10 to 10
An organic polymer of 0,000, having at least one aromatic ring as a substituent directly bonded to at least one hydroxyl group (-OH) per 500 units of molecular weight, and averaging per 500 units of molecular weight 0.1 to 4 sulfone groups (-SO ₃ ) or polar groups of the following group (a) [group (a): phosphoric acid group (R is a hydrogen atom or a hydrocarbon group, the same applies below), phosphorous acid group Phosphonic acid group Phosphonous acid group Phosphinic acid group Phosphinous acid group Tertiary amino group Quaternary ammonium base (R ¹ and R ² are the same or different and are a linear or branched alkyl group, or a hydroxyalkyl group, or an aromatic group such as a phenyl group, R ³ is the same as R ¹ and R ² or H , X ⁻ is a counter ion, a carboxyl group (—COOH)], and one or more polar groups selected from the average of 0.1 to
The main chain connecting the aromatic rings has a CC bond, a C = C bond, an ether bond (CO-
One or more of anionic, cationic or amphoteric water-soluble organic polymers composed of any one or more of C),
Excellent coating adhesion, corrosion resistance, and workability, which is characterized by coating the surface of a metal material coated with organic polymer composite electroplating containing 0.1 to 30 wt% of the total plating weight. Painted metal material. 2. The coated metal material according to claim 1, wherein the plating film (matrix) that composites the organic polymer is a zinc or zinc alloy film. 3. The water-soluble organic polymer contained in the plating film, wherein one of the sulfone groups or polar groups selected from the group (a) is a sulfone group. The coated metal material according to any one of claims 1 and 2. 4. A plated steel material, which is a material to be coated, is a steel plate plated with an organic polymer composite electrozinc system,
Alternatively, the plated steel sheet is a metal material that has been processed and assembled (before entering the phosphating process) and is in a state of an automobile body (white body). The coated metal material according to the item 1. 5. The coating is a commercially available epoxy resin-based cationic electrodeposition coating, or a commercially available thermosetting solvent-based epoxy coating and solvent-based polyester coating, or a commercially available powder polyester coating, each having a film thickness of 20 to 40 μm. The primary adhesion of the coating material after being applied in a thick condition and baked under standard conditions is 60 kg / cm ² or more in the vertical tensile test method, according to any one of claims 1 to 4. The painted metal material described in. 6. The coated metal material according to claim 5, wherein the primary adhesion of the paint after baking under standard conditions is 100 kg / cm ² or more in the vertical tensile test method. 7. A commercially available thermosetting epoxy resin-based cationic electrodeposition coating or a commercially available thermosetting solvent-based epoxy resin-based coating, solvent-based polyester coating, powder polyester coating, water-based melamine alkyd resin coating. , Or an always-dry acrylic resin paint, each of which has a coating thickness of 20 to 40 μm and is baked (standard conditions), the water-resistant adhesion of the paint is 1 mm after the continuous immersion in 60 ° C hot water for 100 days. The coated metal material according to any one of claims 1 to 6, which has a performance of 100/100 (no peeling) in a cellophane peeling test, that is, has excellent water-proof adhesion of the coating. 8. The water-resistant adhesion of the coating is 10 in a 1 mm cross stitch tape peeling test after continuous immersion in hot water at 60 ° C. for 150 days.
The coated metal material according to claim 7, which has a performance of 0/100 (no peeling), that is, is excellent in coating water-resistant adhesion. 9. After coating and baking under standard conditions, a cross knife is cut by a cutter knife until it reaches the base metal, and a corrosion resistance test (JIS 2371) with 5% salt water is continuously conducted for 2 weeks. The coated metal material according to any one of claims 1 to 8, which is excellent in corrosion resistance after coating and has a maximum peeling width of the coating film of 1 mm or less as a result of a cellophane peeling test on the cross-cut portion. . 10. A vertical tensile test method under the condition that the coating is an epoxy resin type cationic electrodeposition coating or a powder polyester coating, and the coating thickness after baking (standard conditions) is 20 and 40 μm, respectively. The maximum peeling width of the coating is one width
Claim 1 characterized in that it is within 0.5 mm
~ The coated metal material according to any one of 8 11. A metal ion comprising 10 to 10 kinds of one or more kinds.
Weight average molecular weight of 1000 in electroplating bath containing 600g /
~ 1 million organic polymers, having at least one aromatic ring having at least one hydroxyl group (-OH) as a substituent directly bonded to a molecular weight of 500 units, and having a molecular weight of 50
An average of 0.1 to 4 sulfone groups (-SO ₃ ) per 0 unit, or polar groups of the following group (a) [group (a): phosphoric acid group (R is a hydrogen atom or a hydrocarbon group, the same applies below), phosphorous acid group Phosphonic acid group Phosphonous acid group Phosphinic acid group Phosphinous acid group Tertiary amino group Quaternary ammonium base (R ¹ and R ² are the same or different and are a linear or branched alkyl group, or a hydroxyalkyl group, or an aromatic group such as a phenyl group, R ³ is the same as R ¹ and R ² or H , X ⁻ is a counter ion, a carboxyl group (—COOH)], and one or more polar groups selected from the average of 0.1 to
The main chain connecting the aromatic rings has a CC bond, a C = C bond, an ether bond (CO-
Plating in which one or more anionic, cationic or amphoteric water-soluble organic polymers composed of any one or more of C) are added as essential components so that the total amount is in the range of 2 to 200 g / Electrodeposit the metal and water-soluble organic polymer on the surface by electroplating the conductive substrate as a cathode in the bath, the ratio of water-soluble organic polymer is 0.1 ~ 30w relative to the total co-deposition amount
A method for producing a coated metal material, which comprises forming an organic polymer composite plating film controlled to be within a range of t%, and then directly coating various paints on the composite plating surface. 12. The metal ion contained in the plating bath is 10 to 60.
A single metal plating bath containing only 0 g / zinc ion, or a zinc alloy plating bath containing 1 to 600 g / each of one or more different metals other than zinc. A method for producing a coated metal material according to claim 11.