JPH0633514B2 - Composite plated metal material having excellent paint adhesion and corrosion resistance, and method for producing the same - Google Patents

Description

The present invention relates to a composite plated metal material having a novel electroplating film and a method for producing the same.

More specifically, paint adhesion, bare corrosion resistance, post-paint corrosion resistance,
The present invention relates to a composite plated metal material having a novel organic polymer composite electroplated film having excellent properties such as weldability and press workability and having excellent adhesiveness and corrosion resistance, and a method for producing the same.

[Conventional technology]

2. Description of the Related Art Conventionally, zinc or zinc alloy plating has been widely performed to impart aesthetics and corrosion resistance to a metal surface, particularly a steel sheet surface.
Among them, recently, the steel sheet for automobiles is in a severe environment in which automobiles are used due to the spraying of snow-melting salt, and therefore, the proportion of zinc-based plating applied is rapidly increasing in order to prevent rust. These plated metal materials are often used by being coated on the plating for the purpose of increasing corrosion resistance and imparting decorativeness.
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. As a typical example, chemical treatment (chemical conversion treatment) such as a phosphate treatment method or a chromate treatment method with a chromic acid solution, and sand blasting, grid blasting, etc. There is a physical process etc. for giving.
All of these methods are mainly expected to increase the effective adhesive surface area and 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. 3,434,942).
And No. 3461044), and this method is expected to increase the affinity of the coating with the paint 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 not only has a problem of chromium toxicity and wastewater treatment, but also has an 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.

Dispersion plating method of water-insoluble resin is a technology to be noticed, but it is difficult to uniformly disperse and stabilize 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, Paint adhesion is not always sufficient,
There are many problems in terms of physical properties such as poor press workability.

As mentioned above, the current technology is incomplete in plating performance and coating surface treatment technology, but as an industrial need, especially for anticorrosion steel sheets used for automobile bodies, high paint adhesion due to the recent increase in durability. There is a strong demand for rust-preventing steel sheets with excellent corrosion resistance and rust-preventing properties.

[Means for solving problems]

The present invention is a conventional electroplating film, especially a zinc-based plating film,
Furthermore, in view of the drawbacks of coating undercoating, it is intended to complete a multi-functional plating film with excellent paint adhesion, corrosion resistance, weldability, and press workability without applying coating undercoating. is there. That is, the present invention separates from conventional ideas such as conventional adjustment of alloying elements and improvement of coating pretreatment such as chemical conversion treatment and blast treatment, and ideal chemical properties and ideal surface morphology of the plated surface (surface irregularity, As a result of diligent examination of the crystal grain size and its shape,
The above object can be achieved very easily by controlling the crystal particle size and its morphology using a water-soluble organic polymer having a specific chemical structure, and by compounding these water-soluble organic polymers in the plating matrix. I found it and saw the completion here.

That is, the present invention has a weight average molecular weight of 10 in the plating film.
Characterized by having an electroplating film containing 0.05 to 30% by weight, based on the total weight of plating, of one or more water-soluble organic polymers consisting of 100,000 to 100,000 hydroxystyrene-based polymers or their derivatives on the metal surface The present invention relates to a composite plated metal material having excellent paint adhesion and corrosion resistance, and a method for producing the same.

The features are 1) Basic skeleton of water-soluble organic polymer (aromatic, hydroxyl group),
Type of polar group (such as sulfone group), molecular weight (1000-100
10,000) and the like, and the amount of addition to the plating bath and the plating conditions are selected to control the plating crystal particle size and morphology (miniaturization and unevenness) and increase the effective bonding area, which is suitable for the surface of the coating base. That it has a smooth surface.

2) A suitable amount of the specific organic polymer described in 1) and a metal are compounded at the molecular level (molecular coposit), and in addition to the effect of the morphology of the plating surface, the affinity between the plating surface and the coating material, It is the point that the reactivity (bondability) is enhanced and the rust prevention and weldability are enhanced by the action of the composite organic polymer.

The present invention is particularly represented by the following general formula (A) (In the formula; m ≧ 0, n ≧ 3, any number until the weight average molecular weight of the organic polymer of the general formula (A) reaches 1,000,000, 0 ≦ k ≦ 2, 0 ≦ p ≦ 2 , Where k + p + m> 0, R ^{1 to} R ³ are H or an alkyl group having 1 to 5 carbon atoms, X is a polymerizable vinyl-based monomer, Y and Z are the same or different, and Be those selected from, wherein: M is H, an organic cation such as an alkali metal, alkaline earth metal or an amine,,; Y ^1, Y ⁴ is halogen; Y ^2- ~Y ^3- is Harogeion A counter ion such as an organic acid anion or an inorganic acid anion; W is S or 0; R ^{4 to} R ⁶ are the same or different and are alkyl group derivatives such as straight chain or branched chain alkyl groups or hydroxyalkyl groups or aromatics. The group or R ⁴ and R ⁵ may form a ring with the N group. Further, R ⁶ can be H.

R ^{7 to} R ¹³ are the same or different and are a linear or branched alkyl group, or an alkyl derivative group such as a hydroxyalkyl group, an aromatic group, or H; q, s, t, and u are 0 or 1 And r is 0, 1 or 2]), it has been found that a composite plated metal material having excellent paint adhesion and corrosion resistance can be obtained by using a water-soluble organic polymer represented by is there.

In the general formula (A), m, n, k, and p are not defined as integers, but are arbitrary numbers (real numbers) within a certain fixed range. If you think about the monomers that make up the polymer,
Naturally, k and p are integers, m is an integer when considering each block of the constitutional unit, and n is an integer when considering each numerator. However, the polymer is, by its very nature, a mixture, and it is more correct to regard the properties of the polymer as the properties of the mixture than to question its individual building blocks. Therefore, in the present invention,
Formula (A) is expressed as an average composition.

The hydroxystyrene-based organic polymer represented by the general formula (A) is a hydroxystyrene or isopropenylphenol which may or may not have a substituent represented by Y or Z in the general formula (A). (Hydroxy-α-methylstyrene) or hydroxy-α-ethylstyrene homopolymers, their copolymers or their hydroxystyrene-based monomers and other polymerizable vinyl-based monomers (X) Can be a copolymer of The polymerized unit such as hydroxystyrene or isopropenylphenol may be an ortho body, a meta body, a para body or a mixture thereof, but a para body or a meta body is preferable.

Examples of other vinyl monomers in the case of a copolymer include maleic anhydride, maleic acid, acrylic acid, methyl methacrylate, methacrylic acid, glycidyl methacrylate, hydroxyethyl methacrylate, itaconic acid, allyl sulfonic acid. , Styrene sulfonic acid, acryl gine ethyl phosphate, acrylamide, 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, maleimide, vinyl pyridine, acrylic acid ester, methacrylic acid ester, fumaric acid ester or vinyl ester of various organic acids. And so on. In this case, the ratio of the hydroxystyrene unit such as hydroxystyrene unit or isopropenylphenol unit to the other vinyl monomer is 1/10 in molar ratio.
Up to 20/1 is appropriate. Further, as the alkali metal or alkaline earth metal of M in the substituent —SO ₃ M or —CH ₂ —SO ₃ M of the hydroxystyrene unit, Li, Na,
K, Mg, Ca, Sr, Ba, etc. are suitable. The introduction of the sulfone group can be achieved by an ordinary sulfonation method using fuming sulfuric acid or sulfuric anhydride as a sulfonating agent. Substituent of hydroxystyrene unit R ^{4 to} R ⁶ are the same or different and have 1 carbon atom.
~ 36 linear or branched alkyl group, or a hydroxyalkyl group, an aminoalkyl group, a phosphoalkyl group,
An alkyl derivative group such as a mercaptoalkyl group, or a straight chain having 1 to 16 carbon atoms, which is selected from aromatic groups such as a benzyl group substituted with a branched chain alkyl group, wherein the compound (A) is It has a carbon chain until it is no longer water-soluble. R ⁴ and R ⁵ may form a ring. Therefore, preferably, a linear or branched alkyl group,
Examples thereof include a hydroxyalkyl group or an aromatic group substituted with a linear or branched alkyl group having 1 to 5 carbon atoms. The introduction of the tertiary amino group can be easily carried out by, for example, the Mannich reaction using a dialkylamine and formaldehyde. Is obtained.

Further, in order to improve the water solubility, an organic or inorganic acid that neutralizes the amine moiety is used. Acids useful for this purpose include acetic acid, citric acid, oxalic acid, ascorbic acid, phenylphosphonic acid, chloromethylphosphonic acid, mono-, di- and trichloroacetic acid, trifluoroacetic acid, sulfuric acid, phosphoric acid,
Examples thereof include hydrochloric acid, boric acid, nitric acid, hydrofluoric acid, hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid. You may use these individually or in mixture.

The introduction of the quaternary ammonium base can be easily carried out, for example, by the Menschutkin reaction of the above-mentioned tertiary amino compound with an alkyl halide. Is obtained.

Substituent of hydroxystyrene unit R ^{7 to} R ¹³ are the same or different and are H or a linear or branched alkyl group having 1 to 36 carbon atoms or an alkyl group derivative such as a hydroxyalkyl group, an aminoalkyl group, a mercaptoalkyl group or a phosphoalkyl group. Base,
Or a carbon chain until the compound (A) is no longer water-soluble, which is selected from aromatic groups such as a phenyl group substituted with a linear or branched alkyl group having 1 to 16 carbon atoms It has a length. Therefore, preferred is a linear or branched alkyl group having 1 to 8 carbon atoms, a hydroxyalkyl group, or an aromatic group substituted with a linear or branched alkyl group having 1 to 5 carbon atoms. The hydroxystyrene-based polymer represented by the formula (D) is disclosed in, for example, JP-A-53
-47489, the hydroxystyrene-based polymer is first halogenated or halomethylated,
It is obtained by reacting it with a trivalent phosphorus compound (Arbuzov reaction), and then subjecting it to thermal rearrangement.
The compound represented by the formula (C) is, for example, as disclosed in JP-A-53-71190, reacted with phosphoric acid or a phosphoric acid ester group-introduced product after methylation of a hydroxystyrene polymer. It is obtained by Also as a substituent For example, as shown in JP-A-61-34444, a hydroxystyrene-based polymer containing a phosphonium group represented by the formula: CH ₂ Cl conversion) is carried out, and then trivalent phosphite ester is allowed to act to easily obtain. Furthermore, the hydroxystyrene polymer used in the present invention may be produced by any method, and its history is not limited. For example, polyparahydroxystyrene, which is a parahydroxystyrene homopolymer, is easily prepared by cationic polymerization, radical polymerization, polymerization with an organic acid, or thermal polymerization of parahydroxystyrene. Polymerization with organic acids gives polymers with a weight average molecular weight of tens of thousands to hundreds of thousands, and thermal polymerization of thousands of
Tens of thousands of polymers can be obtained, and by radical polymerization of paraacetoxystyrene followed by hydrolysis, hundreds of thousands to 200
About 10,000 polyparahydroxystyrene can be obtained.

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 affects 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. On the other hand, when the molecular weight exceeds 1 million, the plating bath is used with an organic polymer. This is because the solubility in the solution becomes poor and the concentration added to the plating bath becomes limited, which becomes a problem and at the same time the effect of the present invention is difficult to be obtained. 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.

Polar groups such as sulfone groups and phosphoric acid groups (not containing hydroxyl groups and aromatic rings) are particularly important for the solubility of organic polymers in the plating bath, and for the miniaturization of plating crystal grain size and surface irregularities. The preferable range of the polar group density is between 0.1 and 5 on average per 500 units of molecular weight, and more preferably between 1 and 3. This is because if the polar group density is less than 0.1, the solubility in the plating bath will be poor, and if it exceeds 5, the corrosion resistance of the plating film obtained will deteriorate, causing a problem. The polar group is preferably a sulfone group, a phosphorus-containing group, or an amine group. This is because those having these polar groups show excellent water-resistant adhesiveness of the paint. The presence of hydroxyl groups and aromatic rings is particularly important, since it is an essential constituent component of the organic polymer for the electroplating bath of the present invention from the viewpoint of improving coating adhesion and corrosion resistance after coating, and it is preferable that it is bulky. The number present in one molecule is important. The greater the number of hydroxyl groups contained in a unit of molecular weight 500, the better, and the number of aromatic rings is 2.
More than one is preferable. It is preferable that the hydroxyl group is directly attached to the aromatic ring as a substituent because the effect is well exhibited. Factors such as the molecular weight of the water-soluble organic polymer, the constitutional unit, the type and density of the polar group, the type of the main chain, etc. are important factors that play an essential role in the composite plated metal material of the present invention.

As a base electroplating bath to which the additive of the present invention is added, a publicly known or new plating bath can be used, and an acidic bath can be used as a preferable bath. In particular, as the galvanizing bath, a known galvanizing bath containing 10 to 600 g / zinc ion, for example, (1) a sulfate bath using zinc sulfate, a chloride bath using zinc chloride, a borofluoride bath or a mixed bath thereof is used. Commonly known acidic bath including, (2) neutral bath prepared by neutralizing zinc chloride with ammonia, (3)
Zinc pyrophosphate bath using zinc pyrophosphate, zinc, zincate bath consisting of sodium hydroxide, (4) general publicly known galvanizing bath such as zinc cyanide plating bath, among which (1) is preferable .

Further, as a zinc alloy plating bath of the base containing the additive of the present invention, iron, nickel, chromium, cobalt manganese, copper, which is considered as an alloying element in the above zinc plating baths (1) to (4), One or more of the elements such as tin, lead, magnesium, aluminum, etc., each chloride, sulfate,
1 to 600g each selected from fluoride, cyanide, oxide, organic acid salt, phosphate or simple metal
/ Added zinc alloy plating bath can be used.
Of these, the bath constructed based on the bath (1) is preferable.

The amount of the organic polymer added to the plating bath may be in the range of 0.1 to 200 g /, preferably 1 to 100 g /, and most preferably 2 to 50 g /. The reason is 0.1 g /
If the addition amount is less than the above, the achievement of the plating crystal particle size and the unevenness of the plating surface are insufficient, and the chemical properties of the plating film (for example, the primary and secondary adhesion (bondability) to the coating) are also sufficiently improved. Not achieved. On the other hand, when the amount exceeds 200 g /, the plating film becomes brittle and causes problems during press working. Primary adhesion of paint, secondary (water resistance)
1 to 100 g / in order to achieve a well-balanced function including adhesion, corrosion resistance after painting, and workability
Is preferable, and most preferably in the range of 2 to 50 g /, and under these conditions, the above functions can be realized under a wide range of plating conditions.

The additive of the present invention can be prepared by adding one or more of the above-mentioned specific water-soluble organic polymers to the simplest plating bath containing necessary amounts of metal ions, pH buffers and pH adjusters as a plating bath. It has a great feature in that the purpose can be sufficiently achieved, and essentially does not require addition of another plating bath auxiliary agent. On the contrary, rust preventives, brighteners, pit preventives,
In the case of adding an auxiliary agent (organic compound) such as a mist preventive agent or an antifoaming agent, an auxiliary agent based on these many organic compounds or organic polymers, for example, α-naphthalenesulfonic acid, isooctyl polyoxyethylene ether, gelatin, Auxiliaries that have been conventionally used such as coumarin and propargyl alcohol have a risk of significantly deteriorating the essential function of the plating film used in the present invention. . However, in the present invention, other additives may be used in combination as long as they do not impair the essential functions such as paint adhesion and corrosion resistance.

Since the organic polymer is stably dissolved and dispersed in the plating bath used in the present invention after the bath adjustment, it is not necessary to stir the liquid for uniform 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 can be carried out at 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, it is desirable that the relative speed (between plate and plating bath) is about 90 to 120 m / min.

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

Further, the content of the water-soluble organic polymer in the plating film can be used in the range of 0.05 to 30 wt% with respect to the total weight of the plating film,
The range of 0.2 to 15 wt% is preferable. When the co-deposition amount of the organic polymer is small, it approaches the Zn unit plating, so that the paint adhesion effect and the rust preventive effect are hard to appear. On the other hand, when the amount is too large, the plating film becomes brittle and the press workability deteriorates, which becomes a problem.
Considering the balance of each function of paint adhesion, corrosion resistance, and press workability, the preferable range of the amount of organic polymer eutectoid is 0.2.
~ 15wt%, the most preferable organic polymer eutectoid amount is 0.
It exists in the range of 5 to 5 wt%.

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, during 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.

The purpose 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 the miniaturization of crystal grains (it does not mean smoothing).
It is expected that the increase of the effective bonding surface area and the surface irregularity are promoted and the anchor effect is exhibited. Therefore,
There are two directions here: One is the direction of increasing the effective bonding surface area by making the crystal grain size finer. The other one is that the crystal may be coarse, so that it suppresses the crystal growth in a specific orientation plane to form, for example, a flaky crystal form.
This is a direction to form a surface morphology in which the anchor effect is likely to be expressed by forming a plating film that is entangled in a complicated manner. 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 of the present invention is preferably in the range of 10 μ to 50 Å. However, the crystal grain diameter 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 2μ or less, the paint adhesion effect begins to appear, and it becomes remarkable at 5000Å or less.
The best paint adhesion is obtained in the range of 1000 to 50Å.
It is considered that the effect of increasing the effective bonding surface area is remarkable when it is 5000 Å or less, particularly 1000 Å or less.

However, in any case, although the crystal grain size is made finer and the physical effect due to the complicated plating surface (anchor effect) is extremely effective for the primary adhesion of the paint, even the secondary (water resistant) adhesion is achieved. Is not always 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 a composite surface of a specific water-soluble organic polymer of the present invention can realize a plating surface having a low alkali solubility.

The composite plating film obtained by mixing the effects of both the crystal particle size / crystal shape and the composite of the water-soluble organic polymer of the present invention is paint adhesion, bare corrosion resistance, post-coating corrosion resistance, weldability,
Excellent press workability. In particular, the plating film in which the organic polymer of the present invention is composite has excellent affinity with paints.
For this reason, there is no need for chemical conversion treatment such as phosphate treatment or chromate treatment or coating base treatment such as blast treatment, which has been conventionally performed as an essential step at the time of coating. Has great features. Further, the plating film of the present invention,
It has higher paint adhesion and corrosion resistance after painting than the applied one.

In the present invention, the target metal material to be plated is not particularly limited. For example, a metal material such as steel plate, copper, brass, and aluminum can be used.

The composite plating bath used in the present invention has corrosion resistance of metal materials,
In order to further improve the aesthetics, we are thinking of directly applying the paint on the obtained plating film, so
The adhesion function to paint is an essential function required for organic polymer composite plating.

In the practice of the present invention, a multilayer having a plating film layer containing no organic polymer of the general formula (A) in the lower layer, and a composite plating film containing the organic polymer of the general formula (A) in the upper layer. It can also be a plated metal material.

Such a multilayer-plated metal material is in consideration of the hybridization with the electroplating and the hot dip coating, which are conventionally performed and practically contain no organic polymer. That is, the multi-layer plated metal material of the present invention has the conventional electroplating and hot dip coating as the lower layer, and the organic polymer composite plating excellent in paint adhesion is applied to the upper layer while keeping the characteristics of the conventional electroplating and hot dip coating. This is intended to cover the drawbacks (insufficient paint adhesion).

There is no particular limitation on the underlying unplated metal material, and for electroplating, zinc and zinc alloy plating, tin plating, nickel plating, chrome plating, lead and lead alloy plating,
Alternatively, a composite plated metal material in which inorganic particles or a water-insoluble resin is composited may be used. Examples of hot-dip galvanizing include zinc and zinc alloy plating, and aluminum-plated metal materials. The thickness of the upper organic polymer composite plating layer is
If the thickness is 0.1 μ, the characteristics are sufficiently exhibited, but the thickness may be thicker.

The multi-layer plated metal material and the manufacturing method thereof of the present invention can be easily produced by switching the final cell of the plating process to the organic polymer composite plating bath, and the subsequent coating base treatment line such as phosphate treatment or chromate treatment. Is unnecessary.

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 remover (complexing agent), an antifoaming agent, an insoluble suspension agent, an aggregating and precipitating agent for impurities, or a dispersant for eutectoid particles in the dispersion plating method. There is.
Therefore, in the above-mentioned cases, the water-soluble organic compound as the auxiliary agent is not often used to improve the coating adhesion and corrosion resistance as in the present invention, or conversely, it may be deteriorated. Heretofore, these surfactants have been recognized to deteriorate the physical properties of plating (fragility, corrosion resistance, etc.), so that the addition amount thereof has been kept as low as possible, and it has always been used at an extremely low concentration. Although there are few organic compounds or types of organic compounds that have been conventionally used, organic polymers such as gelatin, saccharin, and molasses have problems in their chemical structure. Even if it was taken in, no major advantage other than the gloss effect was obtained. The present invention is largely different from the conventional purpose of use, and its main purpose is to improve paint adhesion and corrosion resistance. Therefore, the method of use is also different. For example, a brightener is generally effective only when three components such as a first to a third brightener are blended, whereas in the present invention, the water-soluble organic polymer 1
The purpose can be sufficiently achieved with the components. 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.

The composite plating film of the present invention can be directly coated on the plating surface without any coating base treatment such as phosphate treatment, chromate treatment or blasting treatment which is generally performed in the past, so that there is no pollution problem associated with the coating base treatment. You can free yourself from various problems such as complexity of process control, and easily achieve labor and energy savings.

As the coating method, known coating methods such as electrodeposition coating, electrostatic spray coating, spray coating and roll coating can be applied. As the coating material, any of electrodeposition coating material, powder coating material, thermosetting coating material, room temperature drying coating material, ultraviolet (UV) curing coating material and electron beam (EB) curing coating material can be used.

[Action]

The composite plating film of the present invention has the characteristic actions shown in 1) to 5) below.

1) The affinity and bondability (hydrogen bond, chelate bond, etc.) with the coating material can be increased by the action of the organic polymer that is micro-complexed in the plating film in the molecular order. As a result, extremely excellent paint adhesion and secondary (water resistant) adhesion functions are exhibited.

2) Corrosion resistance is increased by the insulating effect or rustproof property of the organic polymer co-deposited in the plating film, that is, in the plating crystal grains and grain boundaries.

3) In addition, finer crystals and unevenness of the plating surface increase the effective surface area and develop an anchor effect to improve paint adhesion, and finer crystals improve the corrosion resistance by forming a dense film. .

4) Due to the synergistic effect of 1) and 2), even better paint adhesion,
The plating film has excellent corrosion resistance.

5) The co-deposition amount of the water-soluble organic polymer in the plating matrix depends on the interaction between the molecular weight of the water-soluble organic polymer blended in the plating bath, the basic skeleton, the type of polar group and its density, the blending concentration and the electrolysis conditions. Is decided. 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.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

(1) Plating method Pretreatment: Cold rolled steel sheet was subjected to alkaline electrolytic degreasing, washed with water, and then plated under the following conditions.

Plating bath: The composition of the plating basic bath used is shown in Table 1, and the water-soluble organic polymer is shown in Tables 2-a and 2-b. Table 3 shows the composition of the organic polymer composite plating bath in which these are combined.

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 Å / dm ² . The plating film thickness was all 3 μm. An overcurrent type film thickness meter (Sanko Denshi KK, SL-2L-SM type) was used for film thickness measurement.

In addition, various types of hot dip plated steel sheets used in the production examples (Table 4) of the multilayer plated metal material were commercially available.

(2) Coating method Baking-type powder polyester paint (Nippon Paint
NPC300) was used. This was directly electrostatically spray coated on the plated surface and then baked at 230 ° C. for 5 minutes to give a film thickness of 40 μm.

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

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

Table 3 shows the primary, secondary (water resistant) adhesion and corrosion resistance of various water-soluble organic polymer composite plated metal materials (in the case of single layer plating) according to the present invention together with comparative products.

In the results of the evaluation of the primary adhesion of the coating film by the goggles test, there is a significant difference between the product of the present invention (No. 1 to 70) and the comparative product (No. 71 to 98) except for the comparative products No. 78 and 79. No difference is recognized.

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
As compared with the alloy plating film (No. 71 to 80), it can be seen that the coating film adhesion of the product of the present invention (No. 1 to 70) in which an organic polymer is composited is extremely excellent. Next, the case of the plating film obtained from the plating bath containing the water-soluble organic polymer which does not satisfy the conditions of the present invention is shown as comparative products No. 81 to 90.
The plating film obtained by these baths may improve the primary adhesion of the coating as compared with pure zinc or zinc alloy plating containing no organic polymer, but when compared with the product of the present invention. It can be seen that the function is significantly inferior. Further, even if the plating bath contains a water-soluble organic polymer satisfying the conditions of the present invention, the compounding amount thereof is small and the amount of eutectoid in the plating film is small (No. 9
It can be seen that the paint adhesion is not sufficiently improved in Nos. 1 and 92). Next, the galvanized steel sheet (No. 93-9
Comparing 8) with the product of the present invention, all of the products of the present invention have higher primary adhesion of the coating film than the comparative product except that the product of No. 1 having a small amount of polymer eutectoid is equivalent to the comparative product. You can see that.

Water-resistant adhesion evaluation results do not include organic polymers
When comparing No. 71-80 comparative products, No. 81-92 comparative products, and chemical conversion treated steel plate (No. 93-98) comparative products with the present invention products (No. 1-70), organic polymers Inventive product No. 1 having a relatively small amount of eutectoid is equivalent to Comparative product No. 94 (the chemical conversion treatment plate has a large variation in coating adhesion function) (Inventive product No. 94)
2 to 70) have been found to outperform all comparative products.

From the above results, it was found that coprecipitation of the water-soluble organic polymer according to the present invention with a small amount of zinc metal significantly improved the primary and secondary adhesion of the coating material on the surface of the zinc-based plating.

Regarding the corrosion resistance, the product No. 1 of the present invention is a comparative product (No. 94, 96, 9
The results of the product of the present invention (No. 2 to 70) are significantly higher than those of the comparative product (No. 71 to 98) except that it is equivalent to 8), and the composite plating film according to the present invention has improved corrosion resistance. It can be seen that also has a remarkable effect.

Table 4 shows the coating film primary, secondary adhesion and corrosion resistance of various water-soluble organic polymer composite multilayer plated metal materials according to the present invention together with comparative examples. It can be seen that the coating adhesion and the corrosion resistance are significantly improved by applying the organic polymer composite plating on the upper layer, as compared with the case where the chemical conversion treatment is applied on the pure zinc-based plating film. From this result, it is understood that the physical properties of the lower plating film can be utilized and the surface layer can be provided with the functions such as paint adhesion and corrosion resistance, which are the features of the present invention.

〔The invention's effect〕

The present invention has a great feature in using a water-soluble organic polymer having a specific chemical structure as described above. In the plated metal material of the present invention, since the compounding of the plated metal and the organic polymer occurs on the molecular order, it is possible to impart a high level of paint adhesion, corrosion resistance, etc. by the co-deposition of a relatively small amount of the organic polymer. is there. Therefore, 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 generally used in the past, so it is possible to omit complicated chemical conversion treatment that requires pollution measures. Is. This industrial merit is enormous. Furthermore, by using the plated metal material of the present invention, it is possible to realize the production of a coated metal material without intervening a brittle chemical conversion treatment film. Therefore, it is possible to obtain an ideal pre-coated steel sheet for home appliances or building materials excellent in press working after coating. It can be manufactured.

The plated metal material of the present invention is particularly excellent in paint adhesion and corrosion resistance after coating, and can have both press workability and weldability. Therefore, if it is applied to an anticorrosive steel sheet for automobiles, it has excellent corrosion resistance. It can be a rustproof steel plate.

Further, the plated metal material of the present invention can be used not only as a coating material but also as a surface of a laminated base material such as rubber, organic film or ceramics.

Further, the present invention can be used for manufacturing cans such as food cans, electronic materials such as copper foils, and ornaments.

Further, the plated metal material of the present invention can be easily produced by the conventional electroplating equipment, does not require expensive equipment and a lot of labor, and has a high industrial value.

Furthermore, the organic polymer composite effect of 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 a steel plate. In this case, the effect of the present invention can be maximized.

Further, in the present invention, by combining ceramic particles such as Al ₂ O ₃ and SiO ₂ or dispersion plating of a water-insoluble polymer with the water-soluble organic polymer of the present invention, functions of high paint adhesion and corrosion resistance after coating are obtained. Can be given.
This combination technique is extremely effective as a technique for improving the drawbacks of the conventional dispersion plating film, especially the adhesion of water resistant paint.

Claims (19)

[Claims] 1. The plating film has a weight average molecular weight of 1,000 to
Characterized by having an electroplating film on the surface of a metal material containing 0.05 to 30% by weight of one or more water-soluble organic polymers consisting of 1 million hydroxystyrene polymers or their derivatives, based on the total weight of plating. Composite plated metal material with excellent paint adhesion and corrosion resistance. 2. The structure of the water-soluble organic polymer is represented by the following general formula (A): (In the formula, m and n are m ≧ 0 and n ≧ 3, respectively, and the general formula (A) is used.
An arbitrary number until the weight average molecular weight of the organic polymer reaches 1,000,000; 0 ≦ k ≦ 2, 0 ≦ p ≦ 2, where k + p + m> 0, R ^{1 to} R ³ are H or carbon number 1 to 5 alkyl groups; X is a polymerizable vinyl monomer; Y and Z are the same or different, and Be those selected from, [wherein; M is H, an organic cation such as an alkali metal, alkaline earth metal or an amine,,; Y ^1, Y ⁴ is halogen; Y ^2- ~Y ^3- is Harogeion A counter ion such as an organic acid anion or an inorganic acid anion; W is S or 0; R ^{4 to} R ⁶ are the same or different and are alkyl group derivatives such as straight chain or branched chain alkyl groups or hydroxyalkyl groups or aromatics. The group or R ⁴ and R ⁵ may form a ring with the N group. Further, R ⁶ can be H. R ^{7 to} R ¹³ are the same or different and are a linear or branched alkyl group, or an alkyl derivative group such as a hydroxyalkyl group, an aromatic group, or H; q, s, t, and u are 0 or 1 ; R is 0, 1 or 2]) The composite plated metal material according to claim 1, which is an anionic, cationic or amphoteric hydroxystyrene-based water-soluble organic polymer. 3. The composite plated metal material according to claim 1 or 2, wherein the plating film (matrix) of the matrix phase which is composed of an organic polymer is zinc or a zinc alloy film. 4. The composite plated metal material according to claim 2, wherein the water-soluble organic polymer has a hydroxyl group (—OH) of the substituent of the general formula (A) in the para position. 5. A water-soluble organic polymer represented by the formula (A)
= 0, the hydroxyl group (-OH) of the substituent is in the para position, that is, the following general formula (B) (In the formula, R ^{1 to} R ³ , Y, Z, k, p and n are the same as above)
The composite plated metal material according to claim 2 or 4, which contains an organic polymer represented by. 6. The structure of a water-soluble organic polymer is (Y) _k = (SO
The composite plated metal material according to claim 5, wherein ₃ M) _k , (M is the same as above, 0 <k ≦ 2). 7. The structure of the water-soluble organic polymer is (Z) _p = (Br)
The composite plated metal material according to claim 5 or 6, wherein _p (0 <p ≦ 2). 8. The structure of the water-soluble organic polymer Claims (5) or (6) wherein (0 <p ≦ 2)
The composite plated metal material described in the item. 9. The structure of the water-soluble organic polymer Claims (5) or (6) wherein (0 <p ≦ 2)
The composite plated metal material described in the item. 10. The structure of a water-soluble organic polymer Claims (5) or (6) wherein (0 <p ≦ 2)
The composite plated metal material described in the item. 11. The composite plated metal material according to any one of claims 7 to 10, wherein the structure of the water-soluble organic polymer is k = 0. 12. The structure of a water-soluble organic polymer is R ¹ = R ² = R
³ = H, any one of claims 7 to 10
The composite plated metal material described in the item. 13. The composite plated metal material according to any one of claims 1 to 12, wherein the crystal grain size of plating is 50 Å or more and 1000 Å or less. 14. A multi-layer plated metal material having a composite plating film having a plating film layer containing no organic polymer of the general formula (A) as a lower layer.
The composite plated metal material described in the item. 15. One or more metal ions of 10 to 10 are contained.
Weight average molecular weight of 1000 in electroplating bath containing 600g /
~ 1 million hydroxystyrene polymer or one or more of water-soluble organic polymers consisting of these derivatives as an essential component are added so that the total amount is in the range of 0.1 ~ 200 g / A metal and a water-soluble organic polymer are co-deposited on the surface by electroplating a conductive metal material as a cathode, and the ratio of the water-soluble organic polymer is 0.
A method for producing an organic polymer composite plated metal material having excellent paint adhesion and corrosion resistance, which is controlled to be in the range of 05 to 30 wt%. 16. 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 composite plated metal material according to claim 15. 17. The method according to claim 15 or 16, wherein the amount of eutectoid water-soluble organic polymer is controlled in the range of 0.2 to 15 wt% with respect to the total amount of eutectoid. . 18. The method according to any one of claims 15 to 17, wherein the conductive base material used for the cathode is a metal material such as iron, steel plate, copper plate and lead plate. 19. A conductive substrate used for a cathode is provided on the surface,
The manufacturing method according to any one of claims 15 to 18, which is a plated steel sheet that has been electroplated and hot-dipped.